Comparison of the Accuracy of Implant Position Using Surgical Guides Fabricated by Additive and Subtractive Techniques

Current knowledge about stackable guides: a scoping review

PURPOSE

The rise of stereolithographic surgical guides and digital workflow, combined with a better knowledge of materials and loading principle, has enabled the placement of the temporary prosthesis at the time of implant placement. This scoping review aimed to assess the current knowledge available on stackable guides.

METHODS

The review focused on fully edentulous or requiring total edentulism patients. The procedure studied was the use of stackable guides for edentulous patients in order to place immediate temporary prostheses. The clinical endpoint was immediate placement of the provisional prosthesis after surgery combined with a prior bone reduction using a stackable guide.

RESULTS

12 case reports or case series articles met inclusion criteria, which did not allow an analysis by a systematic review. The included studies were case reports or case series. Most of the articles showed a base stabilized by 3 or 4 bone-pins, anchored in buccal or lingual part. Regarding the accuracy of bone reduction (ranged from 0.0248 mm to 1.98 mm) and implant placement when compared to planned, only 4 articles reported quantitative data. 11 articles showed an immediate loading with the transitional prosthesis after implant placement.

CONCLUSIONS

There are as yet no prospective or comparative studies on the efficiency of this technique. In a reliable way, stackable guides seem to be able to guide the practitioner from the flap elevation to the placement of the temporary screw-retained implant supported prosthesis. Given the lack of studies in this specific field of guided surgery, further studies are needed to confirm the clinical relevance of this technique.

A systematic review of factors impacting intraoral scanning accuracy in implant dentistry with emphasis on scan bodies

PURPOSE

The purpose of this systematic review was to explore and identify the factors that influence the accuracy of intraoral scanning in implant dentistry, with a specific focus on scan bodies (ISBs).

METHODS

Following the PRISMA 2020 guidelines, this study conducted a thorough electronic search across MedLine, PubMed, and Scopus to identify relevant studies. Articles were screened based on titles, abstracts, and full texts for relevance. The Robins I tool assessed the risk of bias in various study types. Data extraction occurred based on predetermined parameters for studying specimens and assessing outcomes.

RESULTS

16 studies met the specified criteria and were consequently included in the systematic review. Due to variations in variables and methods across the selected studies, statistical comparison of results was not feasible. Therefore, a descriptive review approach was chosen, acknowledging the substantial heterogeneity in the reviewed literature.

CONCLUSIONS

The precision of virtual scan results is contingent upon diverse characteristics of ISBs and implants. These factors encompass their placement within the dental arch, structural design, shape, material composition, color, and the manufacturing system, all of which contribute to scan accuracy. Additionally, considerations such as the intraoral scanner (IOS) type, scanning technique, use of scan aids, inter-implant distance, scan span, and the number of implants warrant evaluation. In the context of capturing implant positions, intraoral scanning with ISBs demonstrates comparable accuracy to traditional impression methods, particularly in single and short-span scenarios. However, the existing data lacks sufficient information on in vivo applications to formulate clinical recommendations.

Comparative evaluation on wear resistance of metal sleeve, sleeve-free resin, and reinforced sleeve-free resin implant guide: An in vitro study

BACKGROUND

In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application.

AIM

The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill.

MATERIALS AND METHODS

A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated.

RESULTS

The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05).

CONCLUSION

The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

Accuracy of Dental Implant Placement with Dynamic Navigation-Investigation of the Influence of Two Different Optical Reference Systems: A Randomized Clinical Trial

This randomized prospective clinical study aims to analyze the differences between the computer-assisted planned implant position and the clinically realized implant position using dynamic navigation. In the randomized prospective clinical study, 30 patients were recruited, of whom 27 could receive an implant (BLT, Straumann Institut AG, Basel, Switzerland) using a dynamic computer-assisted approach. Patients with at least six teeth in their jaws to be implanted were included in the study. Digital planning was performed using cone beam tomography imaging, and the visualization of the actual situation was carried out using an intraoral scan. Two different workflows with differently prepared reference markers were performed with 15 patients per group. The actual clinically achieved implant position was recorded with scan bodies fixed to the implants and an intraoral scan. The deviations between the planned and realized implant positions were recorded using evaluation software. The clinical examinations revealed no significant differences between procedures A and B in the mesiodistal, buccolingual and apicocoronal directions. For the mean angular deviation, group B showed a significantly more accurate value of 2.7° (95% CI 1.6-3.9°) than group A, with a value of 6.3° (95% CI 4.0-8.7°). The mean 3D deviation at the implant shoulder was 2.35 mm for workflow A (95% CI 1.92-2.78 mm) and 1.62 mm for workflow B (95% CI 1.2-2.05 mm). Workflow B also showed significantly higher accuracy in this respect. Similar values were determined at the implant apex. The clinical examination shows that sufficiently accurate implant placement is possible with the dynamic navigation system used here. The use of different workflows sometimes resulted in significantly different accuracy results. The data of the present study are comparable with the published findings of other static and dynamic navigation procedures.

Influence of the macrodesign of an implant and the sleeve system on the accuracy of template-guided implant placement: A prospective clinical study

STATEMENT OF PROBLEM

Three-dimensional (3D) implant planning facilitates determining the optimal position and number of implants, in terms of function and esthetics, by taking into account adjacent structures. Template-guided implant placement is an established procedure for implementing this planning, although the accuracy between the planned and the actual implant position is subject to many influences. The influences of the macrodesign of the implants and the sleeve materials used have rarely been investigated clinically.

PURPOSE

The purpose of this prospective clinical study was to investigate the accuracy of template-guided implant placement according to the macrodesign of different implants and the design of the drill sleeve.

MATERIAL AND METHODS

Implants were placed in 60 participants within 3 groups (n=20): tapered implant with a metal sleeve (T-MS), tapered implant with a polymeric sleeve (T-PS), and progressive tapered implant with a polymeric sleeve (XT-PS). After overlaying the 3D implant planning image with the postoperative intraoral scan, deviations were 2-dimensionally related to the implant shoulder (S) and the apex (A) in terms of height (2DHS/2DHA), mesiodistal (2DSmd/2DAmd) and buccolingual (2DSbo/2DAbo), as well as 3-dimensionally on the implant shoulder (3DS), on the apex (3DA), and on the axis deviation (Axis). The groups were compared by using the analysis of variance. The Tukey post hoc test was performed for normally distributed data to identify significant differences among groups (α=.05).

RESULTS

The errors for 2DSmd and 2DSbo were 0.26 to 0.40 mm across all groups. The 3DS group varied between 0.67 and 0.87 mm. No significant differences were found in terms of the material of the sleeves or the macrodesign of the implants (P>.05). Significant differences were found for 2DHS (P=.029) and 2DHA (P=.016) between the groups with the different sleeves. Group T-PS showed the least height deviation.

CONCLUSIONS

In terms of height deviation, significant differences were found among the groups, with deviations depending on the implant type and the sleeve type. Overall, the method showed a high level of accuracy, providing good predictability of the prosthetic rehabilitation.

Influence of implant length and insertion depth on primary stability of short dental implants: An in vitro study of a novel mandibular artificial bone model

Background/purpose

Dental implants are a mainstream solution for missing teeth. For the improvement of dental implant surface treatment and design, short dental implants have become an alternative to various complex bone augmentation procedures, especially those performed at the posterior region of both the maxilla and mandible. The objective of this study was to evaluate the effect of various insertion methods on the primary stability of short dental implants.

Materials and methods

Commercial dental implants were inserted into artificial mandibular bone specimens using various insertion methods (equicrestal position, subcrestal position 1.5 mm, and lateral cortical anchorage) in accordance with an implant surgical guide. Insertion torque value (ITV) curves were recorded while implant procedures were performed. Both maximum ITVs (MITVs) and final ITVs (FITVs) were evaluated. Subsequently, Periotest values (PTVs) and implant stability quotients (ISQs) were measured for all specimens. A Kruskal-Wallis test was conducted to analyze the results for four primary stability parameters, and the Dunn test was used for a post hoc pairwise comparison when a difference was identified.

Results

For all groups, their mean MITVs ranged from 33.6 to 59.4 N cm, whereas their mean FITVs ranged from 17.5 to 43.5 N cm. Insertion torque value, ISQ, and PTV decreased significantly when implants were inserted into subcrestal positions. When implants were inserted in the lateral bicortical position, the four aforementioned parameters yielded greater values.

Conclusion

When 6-mm short implants were inserted in a lateral cortical anchorage position, high primary stability was yielded.

Accuracy in static guided implant surgery: Results from a multicenter retrospective clinical study on 21 patients treated in three private practices

PURPOSE

To evaluate the accuracy of a static computer-assisted implant surgery (s-CAIS) system across different private practices.

METHODS

This retrospective clinical study was based on data retrieved from 21 patients who received 61 implants between 2018 and 2020 in 3 private practices run by surgeons with extensive experience with s-CAIS. All patients were treated using the same s-CAIS system, planning software, template manufacturing process, and surgical guides. The standard tessellation language (STL) file of the intraoral scan of the fixture taken immediately after implant placement was matched with that of the preoperative plan for comparisons of preoperative and planned implant positions with postoperative and actual implant positions. The study outcomes were linear and angular deviations between the planned and actual implant positions.

RESULTS

No surgical or postsurgical complications occurred. The overlap of the two STL files resulted in a mean angular deviation of 2.94° The mean linear deviation at the implant shoulder was 0.73 mm, and that at the apex was 1.06 mm. The mean vertical deviations at the implant shoulder and the apex were 0.29 mm and 0.01 mm, respectively.

CONCLUSION

All cases showed satisfactory accuracy within the limits of this study (small number of patients and retrospective design). These results might be related to the use of a standardized digital workflow by experienced operators.

STATEMENT OF CLINICAL RELEVANCE

The study shows that careful control of each step, from data acquisition to final execution, is key for the accuracy of stent-guided systems.

Advancing accuracy in guided implant placement: A comprehensive meta-analysis: Meta-Analysis evaluation of the accuracy of available implant placement Methods

OBJECTIVES

This meta-analysis aimed to determine the accuracy of currently available computer-assisted implant surgery (CAIS) modalities under in vitro conditions and investigate whether these novel techniques can achieve clinically acceptable accuracy.

DATA

In vitro studies comparing the postoperative implant position with the preoperative plan were included. Risk of bias was assessed using the Quality Assessment Tool For In Vitro Studies (QUIN Tool) and a sensitivity analysis was conducted using funnel plots.

SOURCES

A systematic search was performed on April 18, 2023, using the following three databases: MEDLINE (via PubMed), EMBASE, and Cochrane Central Register of Controlled Trials. No filters or restrictions were applied during the search.

RESULTS

A total of 5,894 studies were included following study selection. Robotic- and static CAIS (sCAIS) had the most accurate and clinically acceptable outcomes. sCAIS was further divided according to the guidance level. Among the sCAIS groups, fully guided implant placement had the greatest accuracy. Augmented reality-based CAIS (AR-based CAIS) had clinically acceptable results for all the outcomes except for apical global deviation. Dynamic CAIS (dCAIS) demonstrated clinically safe results, except for horizontal apical deviation. Freehand implant placement was associated with the greatest number of errors.

CONCLUSIONS

Fully guided sCAIS demonstrated the most predictable outcomes, whereas freehand sCAIS demonstrated the lowest accuracy. AR-based and robotic CAIS may be promising alternatives.

CLINICAL SIGNIFICANCE

To our knowledge, this is the first meta-analysis to evaluate the accuracy of robotic CAIS and investigate the accuracy of various CAIS modalities.

Positional accuracy during the sequence of static computer-assisted implant surgery in three alveolar ridge morphologies: An in vitro study

PURPOSE

This in vitro study aimed to assess the positional accuracy during the sequence of static computer-assisted implant surgery (sCAIS) according to the anatomical characteristics of the alveolar ridge.

MATERIAL AND METHODS

Maxillary bone models with six single tooth gaps including clinical scenarios of healed alveolar ridge (HR), single-rooted (SRS), and three-rooted socket (TRS) morphologies were used in this study. Positional deviations during implant placement procedures were evaluated after the pilot osteotomy (PD), final osteotomy (FD), and implant placement with respect to the pre-planned implant position by using a software package. ANOVA and post hoc analyses were performed.

RESULTS

A total of 90 implants were included in this study. Higher mean angular, crestal, and apical deviations were found after the PD and FD (3.5 ± 2.4°, 0.7 ± 0.3 mm, and 1.4 ± 0.8 mm versus 3.6 ±2.2°, 0.6 ± 0.3 mm, and 1.2 ± 0.6 mm) compared to IP (2.8 ± 1.6°, 0.7 ± 0.3 mm, and 1.2 ± 0.5 mm, p ≤ 0.004). Implants placed in TRS demonstrated higher mean angular, crestal, and apical deviations (4.0 ± 1.7°, 0.8 ± 0.3 mm, and 1.6 ± 0.5 mm) compared to implants placed in SRS (2.5 ± 1.2°, 0.7 ± 0.3 mm, and 1.1 ± 0.4 mm) or HR (2.0 ± 0.9°, 0.5 ± 0.3 mm, and 0.8 ± 0.4 mm, p < 0.001).

CONCLUSIONS

Positional deviations during sCAIS procedures are initiated with the first implant osteotomy and persist throughout the drilling sequence. However, deviations slightly decreased after implant placement. The alveolar ridge morphology is strongly associated with positional deviations. Higher deviations were observed in three-rooted and single-rooted sockets simulating an immediate approach compared to healed sites simulating a delayed protocol.

A systematic review of the accuracy of digital surgical guides for dental implantation

PURPOSE

This review aimed to reveal the influence of implant guides on surgical accuracy with regard to supporting types, manufacturing methods and design (including fixation screws and sleeves).

METHODS

A literature search related to accuracy of surgical guides for dental implantation was performed in Web of Science and PubMed. Studies with in vivo or in vitro deviation data published in recent 5 years (2018-2022) were included and assessed by Newcastle-Ottawa Scale with regard to risk of bias and reliability degree of clinical studies. Accuracy-related deviation data were summarized as forest plots and normal distributions.

RESULTS

Forty-one articles were included with high degree of credibility. Data showed that implant surgery accuracy can be achieved with mean distance deviation < 2 mm (most < 1 mm) and angular deviation < 8° (most < 5°).

CONCLUSIONS

Bilateral tooth-supported guides exhibited highest in vitro accuracy and similar in vivo accuracy to unilateral tooth-supported guides; mucosa-supported guides exhibit lowest in vivo accuracy, while its in vitro data showed low credibility due to mechanical complexity of living mucosa tissue. Milling exhibited higher in vivo accuracy of guides than 3d-printing, though further data support was needed. Design of fixation screws and sleeves of implant guides affected the surgical accuracy and might remain a research focus in near future. However, lack of universal evaluation standards for implantation accuracy remained a major problem in this field. The influence of implant guides on surgical accuracy revealed in this review might shed light on future development of dental implantology.

An additively manufactured, magnetically retained, and stackable implant surgical guide: A dental technique

The digital workflow for designing and fabricating a magnetically retained and stackable additively manufactured implant surgical guide is described. The technique should improve the stability of the stackable surgical guide and the accuracy of implant placement.

Effect of print orientation, storage conditions, and storage time on intaglio surface accuracy of implant surgical guides fabricated by using a stereolithography technology

STATEMENT OF PROBLEM

The accuracy of printed implant surgical guides can be affected by different factors that negatively impact the planned implant position. How print orientation, storage time, and conditions influence manufacturing accuracy remains uncertain.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of print orientation, storage conditions, and storage time on the intaglio surface accuracy of implant surgical guides manufactured by using a stereolithography (SLA) printer.

MATERIAL AND METHODS

A tooth-supported maxillary implant surgical guide design (control file) was used to fabricate the specimens (N=40, n=10). Four groups were created based on the print orientation used: 0 (Group 0), 45 (Group 45), 70 (Group 70), and 90 degrees (Group 90). The specimens were fabricated using an SLA printer (Form 3B+) and a biocompatible dental resin (Surgical Guide Resin V1) following the manufacturer's recommended protocol. Each group was divided into 2 subgroups based on the storage conditions: light (L subgroup) and dark (D subgroup) settings. Each specimen was digitized by using a desktop scanner (Medit T710) at days 0, 1, 7, and 14. The control file and each digitized specimen were superimposed by using the best-fit technique with a metrology program (Geomagic Control X). The root mean square (RMS) error was used to calculate the discrepancies between the control files and specimen files. Three-way ANOVA and pairwise comparison Tukey tests were used to analyze trueness. The Levene test was used to assess precision (α=.05).

RESULTS

Significant trueness discrepancies were found among the groups tested (P<.001), but no significant differences were found among the subgroups (P=.100) and the storage times analyzed (P=.609). Additionally, the Tukey test showed significant RMS error mean value discrepancies between Group 0 and Group 45 (P<.001), Group 0 and Group 90 (P<.001), Group 45 and Group 70 (P<.001), and Group 70 and Group 90 (P<.001). The Levene test revealed significant SD discrepancies among the groups tested (P<.05).

CONCLUSIONS

The trueness and precision of the intaglio surface of the implant surgical guides manufactured by using the printer and material tested were affected by the print orientation. However, storage conditions over a 14-day period did not impact the intaglio accuracy of the specimens.

Autoclaving-induced dimensional changes of three-dimensional printed surgical guides: An in vitro study

OBJECTIVES

Surgical guides are frequently used for dental implant placement. The aim of this study was to evaluate the impact of the 3D printing process itself and subsequent steam autoclaving on the dimensional stability of five different resin/printer combinations (RPCs).

MATERIALS AND METHODS

Fifty identical surgical guides (10 per group) were produced consisting of five RPCs. Half of the guides (5 per group) were steam autoclaved with cycle 1 (121°C, 1 bar, 20.5 min) and the other half with cycle 2 (134°C, 2 bar, 5.5 min). All guides were scanned with a structured-light (SL) 3D scanner before (T0) and after (T1) autoclaving. Linear measurements along the x-, y-, and z-axes were performed at landmarks on the original STL file and on SL scans at T0 and T1, respectively. Wilcoxon signed-rank test, Kruskal-Wallis test, and linear mixed-effects models were performed, depending on the analysis.

RESULTS

Three-dimensional printing was associated with significant dimensional alterations for all RPCs. Steam autoclaving using cycle 1 was associated with significant shrinkage in x- (1 RPC), y- (2 RPCs), and z-direction (2 RPCs), while cycle 2 was also associated with shrinkage in x- (2 RPCs), y- (1 RPC), and z-direction (1 RPC). One resin did not present any dimensional changes independently of the cycle.

CONCLUSIONS

The majority of the guides presented minor but significant shrinkage due to 3D printing itself and both steam autoclaving cycles, the extent varied between different RPCs. Whether these changes compromise implant placement accuracy remains to be investigated.

Investigating the implant position reproducibility of optical impressions obtained using an intraoral scanner and 3D-printed models fabricated using an intraoral scanner

PURPOSE

This study aims to examine the effect of the size of the intraoral scanning area on implant position reproducibility and compare the implant position reproducibility of plaster models fabricated using the silicone impression technique, the digital model of an intraoral scanner, and three-dimensional (3D)-printed models fabricated using an intraoral scanner.

METHODS

Scanbodies were attached to an edentulous model with six implants (master model) and were scanned using a dental laboratory scanner to obtain basic data. The plaster model was fabricated using the open-tray method (IMPM; n = 5). The master model was then scanned in various implant areas using an intraoral scanner to obtain data (IOSM; n = 5); the scanning data of six scanbodies were used to fabricate the 3D-printed models (3DPM; n = 5) using a 3D printer. Scanbodies were attached to the implant analogs of the IMPM and 3DPM models and data were obtained using a dental laboratory scanner. The basic data and IMPM, IOSM, and 3DPM data were superimposed to calculate the concordance rate of the scanbodies.

RESULTS

The concordance rate of intraoral scanning decreased as the number of scanbodies increased. Significant differences were observed between the IMPM and IOSM data, and between the IOSM and 3DPM data; however, the IMPM and 3DPM data did not differ significantly.

CONCLUSIONS

The implant position reproducibility of the intraoral scanner decreased with an increase in the scanning area. However, ISOM and 3DPM may provide higher implant position reproducibility than plaster models fabricated using IMPM.

Full-Arch Guided Restoration and Bone Regeneration: A Complete Digital Workflow Case Report

OBJECTIVE

complex rehabilitations present multiple difficulties, regarding both the planification of the surgery and the design of the prothesis. A digital approach can support the workflow, as well as the degree of intraoperative precision, and improve the long-term prognosis.

METHODS

A surgical guide was designed for implant placement. An extensive regeneration of the upper jaw was performed with contextual implant insertion, and a delayed load rehabilitation was chosen. After four months, a second surgery and a simultaneous soft tissue augmentation was performed, and a 3D-printed temporary restoration was placed. After another two months, new dental and facial scans, smile design, and facial bite registrations were obtained. Upper and lower dentures were built using an exclusively digital workflow. Both metal substructures were passivated and cemented in one session; in the following appointment, the aesthetic and occlusal checks were carried out. During the third visit, both prostheses were delivered.

RESULTS

Careful case planning and the surgical guide made it possible to achieve primary stability and acceptable emergence profiles in an extremely reabsorbed upper jaw. Leukocyte-Platelet Rich Fibrin (L-PRF) made the extensive bone regeneration more approachable and lowered the post-operative pain and swelling, while speeding up the soft tissue healing process. During the re-entry surgery, the volumes of soft tissues were increased to improve aesthetics, and the amount of keratinized gingiva around the six implants was also increased. Smile design and facial scans have provided the means to create acceptable aesthetics and function in a few sessions with minimal patient discomfort.

CONCLUSIONS

Computer-assisted implantology is a safe and precise method of performing dental implant surgery. Preliminary studies have a high degree of accuracy, but further studies are needed to arrive at a fully digital clinical protocol at all stages.

Comparative Analysis of Three Facial Scanners for Creating Digital Twins by Focusing on the Difference in Scanning Method

BACKGROUND

Multi-dimensional facial imaging is increasingly used in hospital clinics. A digital twin of the face can be created by reconstructing three-dimensional (3D) facial images using facial scanners. Therefore, the reliability, strengths, and weaknesses of scanners should be investigated and approved; Methods: Images obtained from three facial scanners (RayFace, MegaGen, and Artec Eva) were compared with cone-beam computed tomography images as the standard. Surface discrepancies were measured and analyzed at 14 specific reference points; Results: All scanners used in this study achieved acceptable results, although only scanner 3 obtained preferable results. Each scanner exhibited weak and strong points because of differences in the scanning methods. Scanner 2 exhibited the best result on the left endocanthion; scanner 1 achieved the best result on the left exocanthion and left alare; and scanner 3 achieved the best result on the left exocanthion (both cheeks); Conclusions: These comparative analysis data can be used when creating digital twins through segmentation, selecting and merging data, or developing a new scanner to overcome all shortcomings.

Guided Autotransplantation of Impacted Canines Using a CAD/CAM Surgical Template

Autotransplantation is a potential treatment alternative when orthodontic traction of an impacted tooth is difficult. In this article, we describe two cases of guided autotransplantation of an impacted canine using a computer-aided designed and manufactured surgical template. The impacted canine was segmented on preoperative cone-beam computed tomography images to ensure a sufficient periodontal ligament space and placement of the donor tooth with the least pressure on it. The canine was virtually transposed using a simulation program considering the adjacent teeth. The surgical template, which was connected to the occlusal stop on adjacent teeth, was designed and 3D-printed with polymer resin. The recipient site was prepared using the surgical template, followed by immediate transplantation of the surgically extracted canine into the socket. The transplanted donor tooth was positioned in planned infra-occlusion to prevent occlusal interference. It was then splinted with the adjacent teeth for initial stabilization. During follow-up, one transplanted tooth showed pulp canal obliteration and the other had suspected pulp necrosis; endodontic treatment was performed. One year after the procedure, the periradicular condition of both teeth was favorable.

Accuracy of dental implant placement using static versus dynamic computer-assisted implant surgery: An in vitro study: Accuracy of static vs. dynamic CAIS

OBJECTIVES

This in-vitro study compared the accuracy of implant placement using static versus dynamic computer-assisted implant surgery (CAIS) at two implant sites.

METHODS

Partially edentulous maxillary models were 3D-printed, and two implants (Straumann TL RN4.1 × 10mm) were inserted in FDI positions 15 and 16 per model using two CAIS approaches (10 models per approach). A three-dimensional (3D) reconstruction tool was used for implant planning, surgical guide design, and measuring implant positioning accuracy. In static CAIS, the implants were placed with 3D-printed surgical guides (n=20); in dynamic CAIS, real-time navigation was performed (n=20). Primary outcomes were defined as coronal and apical global deviation as well as angular deviations and deviation comparison between implants placed at positions 15 and 16; the secondary outcome was the bi-directional deviation in mesial-distal, buccal-palatal, and apical-coronal direction.

RESULTS

The mean±SD 3D-deviation at implant platform and apex levels for static CAIS in position 15 was 0.81±0.31mm, 1.41±0.37mm, and in position 16 was 0.67±0.31mm, 1.07±0.32mm.

PRIMARY OUTCOMES

buccal-palatal deviation is higher using static CAIS, and mesial-distal deviation is higher in dynamic CAIS. In position 15, mesial-distal deviation at the apex and the platform were lower in static approaches than in dynamic ones. In implant position 16, buccal-palatal deviation at the apex was lower in the dynamic group than with static ones.

SECONDARY OUTCOMES

for bi-directional analysis, buccal-palatal deviation at the platform (P=0.0028) and mesial-distal deviation at the apex (P=0.0056) were significantly lower in molar sites using static CAIS. Mesial-distal deviation at the apex (P=0.0246) revealed significantly lower values in position 16 following dynamic CAIS.

CONCLUSIONS

Both static and dynamic CAIS resulted in accurate implant placement. However, dynamic CAIS exhibited higher deviation in the mesial direction in an in-vitro setting. In addition, the implant site affects the accuracy of both CAIS approaches.

CLINICAL SIGNIFICANCE

Static CAIS demonstrates the highest accuracy for guided implant placement today.

Influence of alveolar ridge morphology and guide-hole design on the accuracy of static Computer-Assisted Implant Surgery with two implant macro-designs: An in vitro study

OBJECTIVES

The primary aim of this in vitro study was to evaluate the influence of alveolar ridge morphologies on the accuracy of static Computer-Assisted Implant Surgery (sCAIS). The secondary aims were to evaluate the influence of guide-hole design and implant macro-design on the accuracy of the final implant position.

METHODS

Eighteen standardized partially edentulous maxillary models with two different types of alveolar ridge morphologies were used. Each model was scanned via cone beam computer tomography prior to implant placement and scanned with a laboratory scanner prior to and following implant placement using sCAIS. The postsurgical scans were superimposed on the initial treatment planning position to measure the deviations between planned and postsurgical implant positions.

RESULTS

Seventy-two implants were equally distributed to the study groups. Implants placed in healed alveolar ridges showed significantly lower mean deviations at the crest (0.36 ± 0.17 mm), apex (0.69 ± 0.36 mm), and angular deviation (1.86 ± 0.99°), compared to implants placed in fresh extraction sites (0.80 ± 0.29 mm, 1.61 ± 0.59 mm, and 4.33 ± 1.87°; all p<0.0001). Implants placed with a sleeveless guide-hole design demonstrated significantly lower apical (1.02 ± 0.66 mm) and angular (2.72 ± 1.93°) deviations compared to those placed with manufacturer's sleeves (1.27 ± 0.67 mm; p = 0.01, and 3.46 ± 1.9°; p = 0.02). Deep-threaded tapered bone level implants exhibited significantly lower deviations at the crest (0.49 ± 0.28 mm), apex (0.97 ± 0.63 mm), and angular deviations (2.63 ± 1.85°) compared to shallow-threaded parallel-walled bone level implants (0.67 ± 0.34 mm; p = 0.0005, 1.32 ± 0.67 mm; p = 0.003, and 3.56 ± 1.93°; p = 0.01).

CONCLUSIONS

The accuracy of the final implant position with sCAIS is determined by the morphology of the alveolar ridge, the design of the guide holes, and the macrodesign of the implant.

CLINICAL SIGNIFICANCE

Higher accuracy in the final implant position was observed with implants placed in healed alveolar ridge morphologies, in implants with deep-threaded tapered macro-design, and when sleeveless surgical guide holes were used.

The Accuracy of Post and Core Fabricated with Digital Technology

PURPOSE

To compare the accuracy of post and cores created with three different fabricating techniques: direct conventional, machine milling, and three-dimensional (3D) printing.

MATERIALS AND METHODS

Thirteen extracted single root central incisors were selected. Root canal treatment and tooth preparation for crown were performed on all teeth. Post space preparation of 11 mm was created using prefabricated fiber post drill to standardize post space width and length. Root canal impressions were performed on all teeth using polyvinyl siloxane impression material. Each impression was then three dimensionally scanned using an extraoral lab scanner. The scanned impressions were used to design digital files of post and cores with 3Shape CAD software. The digitally designed post and cores were used to fabricate 3D printed and milled post and core resin patterns. The same teeth were used to fabricate post and core with conventional technique (direct duplication of root canal with resin pattern). All posts were then scanned before being invested and then cast using base metal educational alloy. The metal post and cores were tried in with sample teeth and manually adjusted until found to be clinically acceptable. The post and cores were scanned in different stages to perform digital volume measurement using Geomagic Control software to determine accuracy. Pairwise comparisons were accomplished using exact version of the sign test (α = 0.05).

RESULTS

These three techniques of post and core fabrication showed different results in the various stages of fabrication. The accuracy of 3D printed resin pattern (26.89 ±11.09 mm³ ) was found to be inferior compare to milled resin pattern (28.20 ±11.41 mm³ , p = 0.0002). However, dimensional stability of the 3D printed resin pattern before and after casting (0.56 ±0.95 mm³ ) was found to be superior to milled resin pattern (0.79 ±0.89 mm³ ) and direct resin pattern (2.51 ±1.38 mm³ , p = 0.00002). All three techniques showed significant volume reduction after adjustment (p = 0.0002). In the final stage, the adjusted metal post and core fabricated with three different techniques showed no statistical different in accuracy (p = 0.15).

CONCLUSION

Digitally fabricated post and cores have the same degree of accuracy as those fabricated using the gold standard direct conventional post and core technique.

How to Avoid Errors When Using Navigation to Place Implants - A Narrative Review

PURPOSE

Surgeons placing implants use navigation for implant placement accuracy. The importance of this review is to document the sources of error that are involved with navigation so surgeons can recognize factors to decrease error. The objective is to provide surgeons with a reference to optimize navigation.

METHODS

Pubmed.gov was the information source. Years reviewed included 2010 to 2022. The inclusion criteria included only articles in peer-reviewed journals. In vitro results were included only if they involved testing of variables microgap, cone beam computerized tomography (CBCT) accuracy evaluation, or accuracy of printed models. Variables were searched and evaluated. Data collected included the objectives and outcomes of the study including statistical significance. The conclusions made by the authors were confirmed by evaluating the data analysis, and then these conclusions were listed in each error-related topic.

RESULTS

The search used terms which included guided implant surgery complications (n = 4,029), accuracy of CBCT scanners (n = 319), accuracy of implant navigation (n = 983), and the error between drills and static guides (n = 3). From this search, 70 articles were collated that satisfied the inclusion criteria. There are multiple sources of error that are less than 1 mm, including but not limited to errors associated with the scanner and method for scanning, errors associated with merging scanned files with the CBCT scan, errors using different guide stent fabrication methods, errors associated with intraoperative techniques, the learning curve, and planning error. If small errors are not taken into consideration, implant placement errors can exceed 1-2 mm of platform location and angulation errors in excess of 8°.

CONCLUSION

The surgeon needs to take into consideration controllable factors that will result in the avoidance of implant malposition and thus be able to effectively utilize navigation for accurate implant placement.

Accuracy of keyless vs drill-key implant systems for static computer-assisted implant surgery using two guide-hole designs compared to freehand implant placement: an in vitro study

PURPOSE

This in vitro study aimed at comparing the accuracy of freehand implant placement with static computer-assisted implant surgery (sCAIS), utilizing a keyless and a drill-key implant system and two guide-hole designs.

METHODS

A total of 108 implants were placed in 18 partially edentulous maxillary models simulating two different alveolar ridge morphologies. 3D digital deviations between pre-planned and post-operative implant positions were obtained. Guide material reduction was assessed in the keyless implant system for the manufacturer's sleeve and sleeveless guide-hole designs.

RESULTS

sCAIS using a sleeveless guide-hole design demonstrated smaller mean angular, crestal and apical deviations compared to sCAIS utilizing a manufacturer's sleeve and the freehand group (2.6 ± 1.6°, vs 3.3 ± 1.9°, vs 4.0 ± 1.9°; 0.5 ± 0.3 mm, vs 0.6 ± 0.3 mm, vs 0.8 ± 0.3 mm; and 1.0 ± 0.5 mm, vs 1.2 ± 0.7 mm, vs 1.5 ± 0.6 mm). Smaller angular and apical mean deviations were observed in the keyless implant system as compared with the drill-key implant system (3.1 ± 1.7°, vs 3.5 ± 1.9°, p = 0.03; and 1.2 ± 0.6 mm, vs 1.4 ± 0.7 mm, p = 0.045). Overall, smaller angular, crestal, and apical deviations (p < 0.0001) were observed in healed alveolar ridges (2.4 ± 1.7°, 0.5 ± 0.3 mm, and 0.9 ± 0.5 mm) than in extraction sockets (4.2 ± 1.6°, 0.8 ± 0.3 mm, and 1.6 ± 0.5 mm). Higher mean volumetric material reduction was observed in sleeveless than in manufacturer's sleeve guide-holes (- 0.10 ± 0.15 mm³, vs - 0.03 ± 0.03 mm³, p = 0.006).

CONCLUSIONS

Higher final implant positional accuracy was observed in sCAIS for the keyless implant system, with a sleeveless guide-hole design, and in healed ridges. Sleeveless guide holes resulted in higher volumetric material reduction compared with the manufacturer's sleeve.

Fixation Pins Increase the Accuracy of Implant Surgery in Free-End Models: An In Vitro Study

PURPOSE

Implant surgical guides, in combination with implant planning software, have been designed for accurate surgery, especially in partial edentulism. The purpose of this study was to examine the effect of fixation pins of surgical guides on the accuracy of static computer-assisted implant surgeries in a maxillary free-end situation.

MATERIALS AND METHODS

This in vitro study was conducted to compare surgical guides using various fixation pin protocols in implant surgery. A patient dental model with missing teeth from maxillary right first premolar to third molar was used as the study model… Implant placement was planned at maxillary right first premolar, right first molar, and right second molar; Straumann full guide templates were designed and fabricated using the coDiagnostiX software. The experiment involved surgical guides with no fixation pins (NF), buccal unilateral fixation pin (BF), palatal unilateral fixation pin (PF), and bilateral fixation pins on the buccal and palatal sides (BPF), based on the position and number of fixation pins. The deviation between the actual and planned positions was used to evaluate implant accuracy. The fixation pin protocols were the primary predictive variables. Angular, 3D platform, and 3D apex deviations were the primary outcome variables. Statistical analysis was performed using the one-way analysis of variance and Tukey's test (α = 0.05).

RESULTS

NF generated the maximum angular deviation (3.65 ± 1.39°), 3D platform deviation (1.58 ± 0.55 mm), and 3D apex deviation (2.18 ± 0.79 mm), whereas BPF produced the minimum angular deviation (1.88 ± 0.86°), 3D platform deviation (1.09 ± 0.51 mm), and 3D apex deviation (1.53 ± 0.45 mm). A statistically significant difference between NF and BPF in the angular deviation, 3D platform, and apex deviation (P < .0001, P = .009, and P = .002, respectively) was identified. The unilateral fixation pin exerted a significant effect only on the angular accuracy (BF, P = .0018; PF, P = .0001).

CONCLUSION

In a maxillary free-end situation, templates with a fixation pin generate better implant accuracy than those without it. A bilateral fixation pin protocol may produce less deviation than those without fixation pins. The implant accuracy does not appear to be affected by the position of the unilateral fixation pin.

Prevention of peri-implant disease in edentulous patients with fixed implant rehabilitations

OBJECTIVES

To provide an overview about the current approaches to prevent peri-implant diseases in edentulous patients with complete-arch implant-supported prostheses, and to review the clinical applications of the latest digital technologies for implant prosthodontics.

METHODS

A review of the guidelines to prevent peri-implant diseases in patient's receiving complete-arch implant-supported prostheses including facially driven treatment planning procedures using either conventional or digital methods, computer-aided implant planning procedures, and prosthodontic design variables including the optimal number and distribution of dental implants, implant to abutment connection type, implant or abutment level design, screw- or cement-retained alternatives, prostheses contours, and material selection is provided. Furthermore, an outline of the current therapeutic management approaches to address peri-implant diseases is reviewed.

CONCLUSIONS

Clinicians should understand and know different planning and design-related variables that can affect biological and mechanical complication rates of complete-arch implant-supported prostheses. Maintenance protocols are fundamental for minimizing biological and mechanical complications.

Investigation on the application of digital guide templates guided dental implantation in China

BACKGROUND

The aim of this survey is to investigate the application of digital guide templates (DGTs) across China, and the views and attitudes of oral health professionals toward them.

METHODS

This survey was prepared, distributed, and collected by WJX. Chinese oral health professionals were invited to participate in it. The basic information of respondents, the application of DGTs, and the views and attitudes toward their status quo and development were statistically described. Chi-square test was used to evaluate the correlation between the basic information of respondents and the application of DGTs as well as the views and attitudes toward them.

RESULTS

A total of 276 questionnaires were collected, of which 273 were identified as valid. 269 (98.5%) respondents were dental clinical workers, 204 (74.7%) were dental clinical implant workers, and 152 (55.7%) had been engaged in the implant industry for more than five years. The chi-square test showed that working years were significantly correlated with the half-guided, tooth-supported, and mucosa-supported DGTs (P < 0.05); and professional backgrounds and working years presented significant differences in the views and attitudes toward the status quo and development of DGTs (P < 0.05). The questionnaires also made a preliminary investigation and evaluation on the factors influencing accuracy, indications, doctors' recommendations and relevant training.

CONCLUSION

Most respondents held a positive attitude toward the accuracy and development of DGTs. This survey can point out the direction for the improvement of DGTs, and provide a reference for the study of factors affecting implant accuracy, the establishment of a training system, and the understanding of clinicians' current views on DGTs. Trial registration This survey was approved by the Ethics Review Committee of Chenghuaxinguanghua Dental Clinic (Approval NO. CDCIRB-D-2021-201).

Additive manufacturing technologies in the oral implant clinic: A review of current applications and progress

Additive manufacturing (AM) technologies can enable the direct fabrication of customized physical objects with complex shapes, based on computer-aided design models. This technology is changing the digital manufacturing industry and has become a subject of considerable interest in digital implant dentistry. Personalized dentistry implant treatments for individual patients can be achieved through Additive manufacturing. Herein, we review the applications of Additive manufacturing technologies in oral implantology, including implant surgery, and implant and restoration products, such as surgical guides for implantation, custom titanium meshes for bone augmentation, personalized or non-personalized dental implants, custom trays, implant casts, and implant-support frameworks, among others. In addition, this review also focuses on Additive manufacturing technologies commonly used in oral implantology. Stereolithography, digital light processing, and fused deposition modeling are often used to construct surgical guides and implant casts, whereas direct metal laser sintering, selective laser melting, and electron beam melting can be applied to fabricate dental implants, personalized titanium meshes, and denture frameworks. Moreover, it is sometimes required to combine Additive manufacturing technology with milling and other cutting and finishing techniques to ensure that the product is suitable for its final application.

Digital Planning for Immediate Implants in Anterior Esthetic Area: Immediate Result and Follow-Up after 3 Years of Clinical Outcome-Case Report

In this case report, we demonstrate how the correct positioning of implants, associated with optimal gingival conditioning, and the correct choice of biomaterial can yield very predictable and fantastic aesthetic results.

OBJECTIVE

We aimed to use dental implants to rehabilitate the area of elements #11 and #21 in a satisfactory surgical and prosthetic manner, using guided surgery, connective tissue, nano-biomaterials, and a porcelain prosthesis.

CASE REPORT

A 32-year-old male patient presented with bone loss of elements #11 and #21, which was proven radiographically and clinically. Thus, oral rehabilitation with the use of dental implants was required. It was decided to proceed via digital planning with the DSD program (Digital smile design) and with the software Exoplan, (Smart Dent-Germany) whenever it was possible to plan immediate provisional and accurate dental implant positioning through reverse diagnostics (Software Exoplan, Smart Dent-German). The dental elements were extracted atraumatically; then, a guide was established, the implants were positioned, the prosthetic components were placed, the conjunctive tissue was removed from the palate and redirected to the vestibular wall of the implants, the nano-graft (Blue Bone^®) was conditioned in the gaps between the vestibular wall and the implants, and, finally, the cemented provision was installed.

RESULTS

After a 5-month accompaniment, an excellent remodeling of the tissues had been achieved by the implants; consequently, the final prosthetic stage could begin, which also achieved a remarkable aesthetic result.

CONCLUSIONS

This report demonstrates that the correct planning of dental implants, which is associated with appropriate soft tissue and bone manipulation, allows for the achievement of admirable clinical results.

An In Vitro Evaluation of the Effect of 3D Printing Orientation on the Accuracy of Implant Surgical Templates Fabricated By Desktop Printer

PURPOSE

To evaluate the effect of different 3D printing orientations on internal and seating accuracy of implant surgical templates fabricated by a digital light processing (DLP) printer.

MATERIALS AND METHODS

A single maxillary model with a missing central incisor was used to design a surgical template for single implant placement. According to the printing orientation, three surgical template groups were included in the study: horizontal (H), angled (A) and vertical (V) (n = 10). For the H group, the templates were produced parallel to the printing platform, while for the V group, the templates were perpendicular to the platform. The A group templates had a 45° angle orientation to the platform. Each template was scanned at the fitting surface and after seating on the master model. The internal accuracy involved measuring the trueness and precision of the internal surface, while for the seating accuracy, the vertical discrepancy after seating the template was measured. To determine the difference among the groups, ANOVA test was applied followed by Tukey post hoc tests (α = 0.05).

RESULTS

The H group had the lowest internal surface inaccuracy (trueness = 100.7 μm; precision = 69.1 μm) followed by A (trueness = 114.0 μm; precision = 77.3 μm) and V (trueness = 120.3 μm; precision = 82.4 μm) groups, respectively (p < 0.001). Similarly, the H group had the most superior seating accuracy (543.8 μm) followed by A group (1006.0 μm) and V group (1278.0 μm), respectively (p < 0.001).

CONCLUSIONS

The orientation of 3D printing of implant surgical templates fabricated by the DLP desktop printer influenced the accuracy of the templates. The horizontally printed templates consistently exhibited superior accuracy. To reduce deviation of implant placement, it is recommended to print the surgical templates with their largest dimension parallel to the printing platform.

Accuracy of guided dental implant surgery using a fully digital workflow: A case series

STATEMENT OF PROBLEM

Computer-guided implant surgery facilitated by intraoral scanning may enhance the efficiency of the digital workflow. However, it is necessary to assess technique accuracy to evaluate the accuracy of implant placement.

PURPOSE

The purpose of this clinical study was to evaluate the accuracy of a virtual computer-aided design and computer-aided manufacturing (CAD-CAM) static guided surgery technique associated with intraoral scanning in partially edentulous participants by analyzing the overlap among preoperative and postoperative cone beam computed tomography (CBCT) scans, virtual planning, and the guided surgery performed.

MATERIAL AND METHODS

Eleven partially edentulous participants underwent CBCT and intraoral scanning (TRIOS3). Data were integrated into a software program (ImplantViewer 3.5) for the virtual planning of implants and 3-dimensional (3D) printing of the prototype CAD-CAM surgical guide. A total of 18 implants were placed using the CAD-CAM static computer-aided implant surgery technique (Strong SW). After 15 days, postoperative CBCT scans were made and 4 variables (angular, coronal, apical, and vertical deviation) were measured to compare the virtually planned implants and the implants placed by analyzing the overlap between preoperative and postoperative of the virtual planning and guided surgery performed using the ImplantViewer 3.5 and Rhino 6 software programs.

RESULTS

Deviations were found in all parameters analyzed. The mean angular deviation was 2.68 ±1.62 degrees; mean coronal deviation, 0.82 ±0.44 mm; mean apical deviation, 1.14 ±0.44 mm; and mean vertical deviation, 0.62 ±0.44 mm.

CONCLUSIONS

The implants placed using the CAD-CAM static guided surgery technique associated with intraoral scanning in partially edentulous participants exhibited angular and linear deviations when compared with virtual planning implants. However, these deviations were not clinically significant.

A Novel Approach to Guided Implant Surgery: A Technical Note

Computer-guided software and kits have significantly improved the clinical applications of implant surgery. Nonetheless, some technical problems are still in evidence during clinical procedures because of cumbersome surgical tools that can limit access to implant sites, mainly in posterior areas of the mouth in the presence of bulky anatomical structures and in patients with reduced mouth-opening capacity. The present paper aimed to present a novel approach to guided implant surgery, describing the technical characteristics of an innovative guided surgical kit made up of modified sleeves and modular surgical drills. The proposed guided surgical kit is based on a novel patented system of sleeves and modular burs, with an increased length of the metal sleeves and a reduced height of the drills. The innovative design of the proposed system would allow the clinician to position guided fixtures in all clinical situations; the reduced encumbrance would be particularly helpful to gain access to the posterior areas of both maxilla and mandible, which have limited inter-arch space, with an easy and user-friendly approach. The modular system could overcome anatomical limitations, such as reduced mouth-opening capacity, and permit clinicians to maintain the stability and integrity of the surgical templates, even in cases where there is very limited intermaxillary space.

The accuracy comparison of 3D-printed post and core using castable resin and castable wax resin

PURPOSE

The purpose of this research was to compare the accuracy of three dimensionally (3D) printed post and core fabricated with two different materials: reinforced wax and castable resin.

METHODS AND METHODS

Fifteen extracted single root central incisors were selected. Root canal treatment and tooth preparation for crown were performed on all teeth. Eleven millimeters post space was created with standardized prefabricated fiber post drill. Polyvinylsiloxane impression material was used for root canal impressions. Each impression was then 3D scanned using an extraoral scanner and cast posts and cores were designed using 3Shape software. The digitally designed post and cores were 3D printed with two different materials: castable wax resin and resin. The castable resin patterns were scanned before and after complete polymerization. The wax patterns were also scanned. Digital volumetric measurement using Geomagic® Control X࣪ software was performed to determine accuracy.

RESULTS

The printed post and core had reduced volume (16.09 ±3.839 mm³ ) compared to the digital design (17.828 ±3.904, p<0.05). Before complete polymerization, the accuracy of 3D printed resin pattern (16.464 ±3.017) was found to be superior to post and core printed with wax (16.193 ±3.018, p<0.05). However, no volume difference was found between completely polymerized resin (16.09 ±3.839) and wax (16.044±3.834, p = 1).

CONCLUSION

3D printed post and core showed significant volume shrinkage from the digital files used to create them. However, different materials have no effect on the accuracy of 3D printed post and core. This article is protected by copyright. All rights reserved.

Dynamic navigation for dental implant placement in single-tooth gaps: A preclinical pilot investigation

OBJECTIVES

To compare the planned (PIP) and transferred implant position (TIP) after dental implant placement in single-tooth gaps utilizing dynamic computer-assisted implant surgery (dCAIS).

METHODS

Five pairs of artificial jaws (n = 5) with four single tooth gaps in FDI (Fédération Dentaire Internationale) regions 16, 25, 36 and 44 were manufactured via injection molding technique. Cone beam computed tomographies (CBCTs) were made and digital implant planning of twenty implants (n = 20) was performed with a dynamic navigation system (DNS, Navident, ClaroNav, Toronto, Canada). After guided drilling and manual implant placement, post-operative CBCTs were made. Global deviations at entry point (two-dimensional, 2D), apex (three-dimensional, 3D), apex (vertical, V) and angulation (in degrees, °) were calculated by DNS software. For statistical analysis, level of significance was set to p < 0.05.

RESULTS

Mean deviation at the implants entry point (2D) was 0.78 ± 0.45 mm (range: 0.10-1.63 mm). For the implants apex (3D) and the implants apex (V) deviations were 1.08 ± 0.50 mm (range: 0.33-2.10 mm) and 0.32 ± 0.22 mm (range: 0.02-0.90 mm), respectively. The median angular deviation (°) was 2.81 ± 2.29° (range: 0.56-9.58°). Statistically significant differences (p < 0.05) were found regarding apex (3D), apex (V), and angulation (°) comparing I.-IV. quadrants.

CONCLUSIONS

Using the investigated dCAIS seems to provide satisfactory results regarding TIP in single-tooth gaps in vitro. Due to documented deviations, a safety distance of more than 2 mm should be respected while implant planning in DNS software.

CLINICAL SIGNIFICANCE

The investigated DNS seems to be reliant in transferring PIP with acceptable deviations in vitro.

An In Vitro Study of the Reproducibility of the Drilling Access of Digitalized Surgical Guides Generated via Three Different Implant Planning Software Programs

Several implant planning software programs are widely use in implant treatments, but there has been no evidence of how different software programs affect the accuracy of static surgical guides used for implant placement. Thus, in this in vitro study, we aimed to compare the accuracy of static surgical guides that were prefabricated from three different software programs, including Implant Studio (Program A) (3Shape®, Copenhagen, Denmark), coDiagnostiX® (Program B) (Straumann®, Basal, Switzerland), and Blue Sky Plan (Program C) (Blue Sky Bio®, LLC, Libertyville, IL, USA). A total of 90 drillable polyurethane models were used as samples in this in vitro study; 30 study models were used to plan the same implant positions and design the surgical guides by each software program (n = 30) and then 90 implants were placed in the models using the surgical guides. The outcomes of the surgical guide accuracy were autonomically measured by the evaluation tool in the coDiagnostiX® (Straumann®, Basal, Switzerland) software program. The deviations between the planned and placed implants were automatically evaluated as three-dimensional and angular deviations. The mean three-dimensional implant position deviations from the implant platform of Program A, Program B, and Program C were 0.55 ± 0.25 mm, 0.52 ± 0.31 mm, and 0.56 ± 0.22 mm, respectively. The mean three-dimensional implant position deviations from the implant apex of Program A, Program B, and Program C were 0.72 ± 0.37 mm, 0.73 ± 0.4 mm, and 0.9 ± 0.46 mm, respectively. The mean depth deviations of Program A, Program B, and Program C were 0.19 ± 0.13 mm, 0.31 ± 0.32 mm, and 0.31 ± 0.22 mm, respectively. The mean angulation deviations of Program A, Program B, and Program C were 1.72 ± 0.88 degrees, 2.05 ± 1.24 degrees, and 2.74 ± 1.81 degrees, respectively. The results indicated that there were no significant differences among the three-dimensional positions at the implant platform, the three-dimensional positions at the implant apex, and the depth deviations between all three groups. However, it was found that there was a significant difference in the angular deviation of the implant position between the three groups (p = 0.02). The mean angular deviation of Program C was significantly greater than the Program A group (p = 0.001). In terms of the deviation directions of the implant platform and implant apex for the three groups, most of the deviations of a larger magnitude were toward the mesio-buccal direction. No matter which program was used to plan the implant position, deviations between the placed implant position and the planned position still occurred. Therefore, when planning implant positions with any implant planning software program, one must take into account an implant position deviation.

Evaluation of different registration methods and dental restorations on the registration duration and accuracy of cone beam computed tomography data and intraoral scans: a retrospective clinical study

OBJECTIVES

To evaluate whether the accuracy and duration of registration for cone beam computed tomography (CBCT) and intraoral scans differ according to the method of registration and ratio of dental restorations to natural teeth.

MATERIALS AND METHODS

CBCT data and intraoral scans of eligible patients were grouped as follows according to the ratio of the number of dental restorations to the number of natural teeth (N): group 1, N = 0%; group 2, 0% < N < 50%; group 3, 50% ≤ N < 100%; and group 4, 100% ≤ N. Marker-free registration was performed with a deep learning-based platform and four implant planning software with different registration methods (two point-based, one surface-based, and one manual registration software) by a single operator, and the time consumption was recorded. Registration accuracy was evaluated by measuring the distances between the three-dimensional models of CBCT data and intraoral scans.

RESULTS

A total of 36 patients, one jaw per patient, were enrolled. Although registration accuracy was similar, the time consumed for registration significantly differed for the different methods. The deep learning-based registration method consumed the least time. Greater proportions of dental restorations significantly reduced the registration accuracy for semi-automatic and deep learning-based methods and reduced the time consumed for semi-automatic registration.

CONCLUSIONS

No superiority in registration accuracy was found. The proportion of dental restorations significantly affects the accuracy and duration of registration for CBCT data and intraoral scans.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: KCT0006710 CLINICAL RELEVANCE: Registration accuracy for virtual implant planning decreases when the proportion of dental restorations increases regardless of registration methods.

Cytotoxicity of polymers intended for the extrusion-based additive manufacturing of surgical guides

Extrusion-based printing enables simplified and economic manufacturing of surgical guides for oral implant placement. Therefore, the cytotoxicity of a biocopolyester (BE) and a polypropylene (PP), intended for the fused filament fabrication of surgical guides was evaluated. For comparison, a medically certified resin based on methacrylic esters (ME) was printed by stereolithography (n = 18 each group). Human gingival keratinocytes (HGK) were exposed to eluates of the tested materials and an impedance measurement and a tetrazolium assay (MTT) were performed. Modulations in gene expression were analyzed by quantitative PCR. One-way ANOVA with post-hoc Tukey tests were applied. None of the materials exceeded the threshold for cytotoxicity (< 70% viability in MTT) according to ISO 10993-5:2009. The impedance-based cell indices for PP and BE, reflecting cell proliferation, showed little deviations from the control, while ME caused a reduction of up to 45% after 72 h. PCR analysis after 72 h revealed only marginal modulations caused by BE while PP induced a down-regulation of genes encoding for inflammation and apoptosis (p < 0.05). In contrast, the 72 h ME eluate caused an up-regulation of these genes (p < 0.01). All evaluated materials can be considered biocompatible in vitro for short-term application. However, long-term contact to ME might induce (pro-)apoptotic/(pro-)inflammatory responses in HGK.

Alveolar ridge preservation reduces the need for ancillary bone augmentation in the context of implant therapy

Background

There is limited information on the need for bone augmentation in the context of delayed implant placement whether alveolar ridge preservation (ARP) is previously performed or not. The primary aim of this retrospective cohort study was to evaluate the efficacy of ARP therapy after tooth extraction compared with unassisted socket healing (USH) in reducing the need for ancillary bone augmentation before or at the time of implant placement.

Methods

Adult subjects that underwent non‐molar single tooth extraction with or without simultaneous ARP therapy were included in this study. Cone beam computed tomography scans obtained before tooth extraction and after a variable healing period were used to record the baseline facial bone thickness and to virtually plan implant placement according to a standard method. A logistic regression model was used to evaluate the effect of facial alveolar bone thickness upon tooth extraction and baseline therapy (USH or ARP) on the need for additional bone augmentation, adjusting for several covariates (i.e., age, sex, baseline KMW, and tooth type).

Results

One hundred and forty subjects that were equally distributed between both baseline therapy groups constituted the study population. Implant placement was deemed virtually feasible in all study sites. Simultaneous bone augmentation was considered necessary in 60% and 11.4% of the sites in the USH and ARP group, respectively. Most of these sites (64.2% in the USH group and 87.5% in the ARP group) exhibited a thin facial bone phenotype (<1 mm) at baseline. Logistic regression revealed that the odds of not needing ancillary bone augmentation were 17.8 times higher in sites that received ARP therapy. Furthermore, the need for additional bone augmentation was reduced 7.7 times for every 1 mm increase in facial bone thickness, regardless of baseline therapy.

Conclusions

Based on a digital analysis, ARP therapy, compared with USH, and thick facial alveolar bone largely reduce the need for ancillary bone augmentation at the time of implant placement in non‐molar sites.

Free-Hand versus Surgical Guide Implant Placement

One of the most key areas of dentistry is dental implant surgery. The use of digital equipment and software in dentistry has developed considerably in recent years compared to other fields of medicine. Since examining the advantages and disadvantages of each approach, along with case studies, can help physicians make informed decisions, this review study aims to raise the awareness of dentists to make easier decisions about using guided or free-hand surgery. When planning for a dental implant, one of the most challenging questions that doctors face is which method to use (guided surgery or free-hand). Choosing the right method, such as other clinical considerations, will depend on the individual circumstances of each patient and the preference of the treating physician. Free-hand surgery is a cost-effective method in which the flap is reflected, and, according to the doctor's diagnostic information, an implant is placed, which in many cases is a useful method. Guided surgery has the highest level of accuracy and control, in which osteotomy is designed and printed through a digital surgery guide, and depending on the complexity of the case and the patient's anatomy, it has a higher level of value than free surgery. The surgical guide helps the surgeon make the implant surgery more accurate, safer, simpler, at a lower cost, and in less time. In fact, there are patterns that convey information about the position of the tooth to the dentist before the implant is placed.

The influence of crown coverage on the accuracy of static guided implant surgery in partially edentulous models: An in vitro study

OBJECTIVE

To evaluate the influence of crown coverage of surgical guides on the accuracy of static computer-assisted implant surgeries (sCAISs) in different partially edentulous situations.

METHODS

Acrylic models with five types of partially edentulous situations were fabricated in this study. In coDiagnostiX software (Dental Wings, Montreal, Canada), surgical templates were designed and fabricated with reduced crown coverage (RCC), standard crown coverage (SCC) and extended crown coverage (ECC). Then, fully guided implant placement into the acrylic models was performed by dental surgeons with more than 10 years of experience. In total, 120 models and 120 guides were manufactured, and 168 bone-level Straumann replica implants (4.1 × 10 mm, Institut Straumann AG, Basel, Switzerland) were inserted. Postoperative implant positions were scanned (Trios 3, 3 shape, Copenhagen, Denmark) and compared with the preplanned virtual positions via coDiagnostiX (Dental Wings, Montreal, Canada). The angular, coronal and apical deviations were measured and analyzed to evaluate the accuracy of implant insertion. Statistical analysis was performed using one-way ANOVA and Tukey's test.

RESULTS

For single tooth missing situations, the RCC group was similar to the SCC group and ECC group in anterior sites. In premolar or molar sites, the SCC and ECC groups had no statistically significant difference (p > .05), while the RCC group had more coronal and apical deviation (p < .05). For multiple teeth missing situations, there was no difference among the RCC, SCC and ECC groups (p > .05). No difference was found among the five edentulous situations with different CCs (p > .05).

CONCLUSION

The CC of templates can significantly affect the accuracy of guided surgeries when implants are inserted in a single gap at posterior sites. Templates with CC extended to the undercut line may be an optimal choice for static guided surgeries.

CLINICAL SIGNIFICANCE

The accuracy of static guided implant surgery can be influenced by the CC of templates, and proper CC with the guide covering extending to the undercut line may contribute to improved accuracy. CC should be taken into consideration when designing surgical templates.

Accuracy Evaluation of Additively and Subtractively Fabricated Palatal Plate Orthodontic Appliances for Newborns and Infants-An In Vitro Study

Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100 µm layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.

Computer-assisted surgery in medical and dental applications

INTRODUCTION

Computer-assisted surgery (CAS) is a broad surgical methodology that utilizes computer technology to both plan and execute surgical intervention. CAS is widespread in both medicine and dentistry as it allows for minimally invasive and precise surgical procedures. Key innovations in volumetric imaging, virtual surgical planning software, instrument tracking, and robotics have assisted in facilitating the transfer of surgical plans to precise execution of surgical procedures. CAS has long been used in certain medical specialties including neurosurgery, cardiology, orthopedic surgery, otolaryngology, and interventional radiology, and has since expanded to oral and maxillofacial application, particularly for computer-assisted implant surgery.

AREAS COVERED

This review provides an updated overview of the most current research for CAS in medicine and dentistry, with a focus on neurosurgery and dental implant surgery. The MEDLINE electronic database was searched and relevant original and review articles from 2005 to 2020 were included.

EXPERT OPINION

Recent literature suggests that CAS performs favorably in both neurosurgical and dental implant applications. Computer-guided surgical navigation is well entrenched as standard of care in neurosurgery. Whereas static computer-assisted implant surgery has become established in dentistry, dynamic computer-assisted navigation is newly poised to trend upward in dental implant surgery.

The Impact of Surgical Guide Fixation and Implant Location on Accuracy of Static Computer-Assisted Implant Surgery

PURPOSE

To evaluate the accuracy of static computer-assisted implant surgery (sCAIS) for tooth-supported free-end dental implantation with the aid/and without the aid of fixation pins to secure the surgical template through comparison between planned, 3D printed guide position and placement implant position.

MATERIALS AND METHODS

Thirty-two duplicated maxillary resin models were used in the present in vitro study. Digital planning was performed and fabrication of a surgical template that allowed implant placement on the distal extension edentulous site of the model (maxillary left side). A first optical scan was performed after fitting the surgical template on the model to assess the deviation at the surgical guide level. After placing implants in the model using the surgical guide, scan bodies were attached to the implants, and a second scan was performed to record the position of placed implants. The digital representations were later superimposed to the pre-operative scan and measurements of implant deviations were performed. Global (coronal and apical), horizontal (coronal and apical), depth and angular deviations were recorded between planned implant position, guide position, and placement implant position. Three-way ANOVA was used to compare implant location (#13, 14, and 15), fixation pin (with or without pin), and guide comparison (planned, guided, and placement).

RESULTS

Final implant placement based on the digital plan and based on the 3D printed guide were very similar except for depth deviation. Use of fixation pin had a statistically significant effect on the depth and angular deviation. Overall, without fixation pins and based on guide versus placement, mean global coronal (0.88 ± 0.36 mm), horizontal coronal (0.55 ± 0.32 mm), and apical (1.44 ± 0.75 mm), and angular deviations (4.28 ± 2.01°) were similar to deviations with fixation pins: mean global coronal (0.88 ± 0.36 mm); horizontal coronal (0.67 ± 0.22 mm) and apical (1.60 ± 0.69 mm); and angular deviations (4.53 ± 2.04°). Horizontal apical without pins (1.63 ± 0.69 mm) and with fixation pins (1.72 ± 0.70 mm) was statistically significant (p = 0.044). Depth deviation without pins (-0.5 ± 0.5 mm) and with fixation pins (-0.16 ± 0.62 mm) was also statistically significant (p = 0.005). Further analysis demonstrated that the final sleeve position on the 3D printed guide was on average 0.5 mm more coronal than the digital plan.

CONCLUSIONS

The use of surgical guides with or without fixation pins can provide clinically acceptable outcomes in terms of accuracy in implant position. There was a statistically significant difference in the accuracy of implant position when utilizing fixation pins only for horizontal apical and depth deviation. Additionally, a statistically significant difference between the planned and the 3D printed surgical guide when considering the sleeve position was detected.

Does the macro design of an implant affect the accuracy of template-guided implantation? A prospective clinical study

Background

An implant prosthesis aims to ensure the best possible rehabilitation of function and esthetics following tooth loss. Template-guided insertion is used to achieve an optimal position of the implant with regard to prosthetic restorability, bone availability, and condition of the surrounding soft tissues. The accuracy of template-guided implant placement is subject to various influencing factors.

The clinically achievable accuracy depending on the macro design of the implant body was investigated in this prospective clinical study.

Material and methods

In this prospective clinical study, 20 implants were placed in 20 patients. The implant had a pronounced conical outer geometry (Conelog ProgressiveLine, Camlog Wimsheim, Germany). Data from a study using an implant with a distinct cylindrical outer geometry were used as a comparison group (Conelog ScrewLine, Camlog, Wimsheim, Germany). The clinically achieved implant position was compared with the planned position.

Results

The evaluation of the two-dimensional deviations in direction resulted in the following mean values (standard deviation) at the shoulder: 0.42 mm (0.33) in the buccolingual direction, 0.27 mm (0.25) in the mesiodistal direction, and 0.68 mm (0.55) in the apicocoronal direction. The mean angular deviation was 4.1° (2.3). The three-dimensional (3D) deviation was 0.94 mm (0.53) at the shoulder and 1.36 mm (0.62) at the apex of the implant.

Significant differences between implants with different macro designs were found in the apicocoronal direction. In connection to this, a significant 3D deviation was found at the implant shoulder.

Conclusions

Significant differences in height were found between the groups. The study had shown that the macro design of an implant has no influence on accuracy in all other directions. Overall, the implants showed a high level of accuracy and a low variation in values. The values were in the range determined by the template-guided insertion system in numerous other investigations. This provides good predictability of prosthetic rehabilitation.

Trial registration

German Register for Clinical Studies (DRKS-ID: DRKS000018939). Date of registration: November 11, 2019.

Accuracy of Computer-Assisted Dynamic Navigation in Implant Placement with a Fully Digital Approach: A Prospective Clinical Trial

Background: This prospective clinical study aimed to investigate a possible deviation between the digitally planned implant position and the position achieved using dynamic navigation. The aim of the study was to establish clinical effectiveness and precision of implantation using dynamic navigation. Methods: Twenty consecutive patients received an implant (iSy-Implantat, Camlog, Wimsheim, Germany). One screw implant was placed in one jaw with remaining dentition of at least six teeth. The workflow was fully digital. Digital implant planning was conducted using cone-beam computed tomography (CBCT) and an intraoral scan of the actual condition. Twenty implants were subsequently placed using a dynamic computer-assisted procedure. The clinical situation of the implant position was recorded using an intraoral scan. Using these data, models were produced via 3D printing, and CBCTs of these models were made using laboratory analogs. Deviations of the achieved implant position from the planned position were determined using evaluation software. Results: The evaluation of 20 implants resulted in a mean angle deviation of 2.7° (95% CI 2.2–3.3°). The 3D deviation at the implant shoulder was 1.83 mm (95% CI 1.34–2.33 mm). No significant differences were found for any of the parameters between the implantation in the upper or lower jaw and an open or flapless procedure (p-value < 0.05). Conclusion: The clinical trial showed that sufficiently precise implantation was possible with the dynamic navigation system used here. Dynamic navigation can improve the quality of implant positioning. In particular, the procedure allows safe positioning of the implants in minimally invasive procedures, which usually cannot be performed freehand in this form. A clinical benefit and effectiveness can be determined from the results.

Accuracy of Computer-Assisted Dynamic Navigation as a Function of Different Intraoral Reference Systems: An In Vitro Study

The aim of this in vitro study was to determine whether the process chain influences the accuracy of a computer-assisted dynamic navigation procedure. Four different data integration workflows using cone-beam computed tomography (CBCT), conventional impressions, and intraoral digitization with and without reference markers were analyzed. Digital implant planning was conducted using data from the CBCT scans and 3D data of the oral models. The restoration of the free end of the lower jaw was simulated. Fifteen models were each implanted with two new teeth for each process chain. The models were then scanned with scan bodies screwed onto the implants. The deviations between the planned and achieved implant positions were determined. The evaluation of all 120 implants resulted in a mean angular deviation of 2.88 ± 2.03°. The mean 3D deviation at the implant shoulder was 1.53 ± 0.70 mm. No significant differences were found between the implant regions. In contrast, the workflow showed significant differences in various parameters. The position of the reference marker affected the accuracy of the implant position. The in vitro examination showed that precise implantation is possible with the dynamic navigation system used in this study. The results are of the same order of magnitude that can be achieved using static navigation methods. Clinical studies are yet to confirm the results of this study.

Bone Temperature Variation Using a 3D-Printed Surgical Guide with Internal Irrigation

Bone overheating is a possible cause of implants early failure. When a surgical guide is used, the risk of heat injury is greater due to the reduced efficacy of the irrigation. The aim of this ex vivo study was to evaluate the effect of an additional built-in irrigation on bone temperature variation during implant osteotomy. Twelve bovine ribs were used. Cone beam computerized tomography (CBCT) was performed and a 3D-printed surgical guide with additional built-in irrigation tubes was produced for each rib. A total of 48 osteotomies were prepared, to compare the supplementary internal irrigation system (Group A) with external irrigation alone (Group B), no irrigation (Group C) and with free-hand surgery with external irrigation (Group D). Temperature was measured by three thermocouples placed at depths of 1.5, 7, and 12 mm. The largest temperature variation at each thermocouple showed median values of 3.0 °C, 1.9 °C, and 2.3 °C in Group 1; 2.3 °C, 1.7 °C, and 0.9 °C in Group 2; 3.2 °C, 1.6 °C, and 2.0 °C in Group 3; 2.0 °C, 2.0 °C, and 1.3 °C in Group 4, respectively. No differences were found among the four groups. In general, the highest temperature increase was observed with the use of the first drill (cortical perforator). Post-experimental CBCT revealed the presence of radiopaque material clogging the aperture of the internal irrigation channels. Additional internal irrigation was not found to significantly contribute to decrease bone temperature in this ex vivo setting.

Fabricating a dual-material, vat-polymerized, additively manufactured static implant surgical guide: A dental technique

Protocols with static computer-aided implant placement provide more tangible clinical advantages than conventional implant placement methods. A technique to manufacture a dual-material implant surgical guide by using a vat-polymerization printer is described. The implant surgical guide combined a resilient intaglio and hard exterior surface. The technique should minimize the clinical adjustments needed to ensure fit and improve patient comfort.

An evaluation of virtually planned and 3D-printed stereolithographic surgical guides from CBCT and digital scans: An in vitro study

STATEMENT OF PROBLEM

The process of manufacturing stereolithographic surgical guides for static computer-guided implant placement involves a series of steps. Errors can be incorporated in various forms and at various stages of manufacturing these guides. Errors introduced during this process have not been fully investigated.

PURPOSE

The purpose of this in vitro study was to assess the errors introduced during the manufacture of stereolithographic surgical guides generated from cone beam computed tomography (CBCT) and digital scans by using a virtual implant planning software.

MATERIAL AND METHODS

Ten stereolithographic surgical guides with the associated standard tessellation language (STL) files of their virtual design were used in this study. The STL files of the virtual design and the scans of the stereolithographic surgical guides were superimposed. Linear deviation at the center of the sleeve top and sleeve base and the angular deviation at the center of the sleeve were measured.

RESULTS

The minimum and maximum linear deviation at the center of the sleeve top and the sleeve base was found to be 0 and 40 μm, with less linear deviation observed at the center of the sleeve top (mean ±standard deviation 18 ±7 μm) than at the center of the sleeve base (20 ±7 μm). The minimum and maximum angular deviation at the center of the sleeve was found to be 0 degrees and 5.9 degrees respectively, with a mean ± standard deviation of 1.36 ±0.74 degrees.

CONCLUSIONS

Errors were found in the sleeve position between the virtual design and the stereolithographically manufactured surgical guide. This error may introduce errors in the final implant position.

Sleeve insert scan body to predict implant placement position by using implant surgical guides: A dental technique

In studies that assessed the accuracy of implant surgical guides, evaluations were based on the placement position of the implant by using a manufactured surgical guide. However, such assessments could involve errors that may occur during implant placement. Therefore, evaluating the 3-dimensional accuracy of the fabrication of the implant surgical guide itself is not enough. In the evaluation method described in this article, location-related information is obtained by connecting a scan body to the sleeve of the surgical guide instead of directly placing the implant. This helps to evaluate the accuracy of the surgical guide without errors in the placement of an implant.

In Vitro Comparison between Metal Sleeve-Free and Metal Sleeve-Incorporated 3D-Printed Computer-Assisted Implant Surgical Guides

The present study aims to compare the accuracy of metal sleeve-free 3D-printed computer-assisted implant surgical guides (MSF group) (n = 10) with metal sleeve-incorporated 3D-printed computer-assisted implant surgical guides (MSI group) (n = 10). Implants of diameter 4.0 mm and 5.0 mm were placed in the left second premolars and bilateral first molars, respectively, using a fully guided system. Closed-form sleeves were used in teeth on the left and open-form sleeves on the right. The weight differences of the surgical guides before and after implant placement, and angular deviations before and after implant placement were measured. Weight differences were compared with Student's t-tests and angular deviations with Mann-Whitney tests. Cross-sectional views of the insert parts were observed with a scanning electron microscope. Preoperative and postoperative weight differences between the two groups were not statistically significant (p = 0.821). In terms of angular deviations, those along the mesiodistal direction for the left second premolars were significantly lower in the MSF group (p = 0.006). However, those along the mesiodistal direction for the bilateral molars and those along the buccolingual direction for all teeth were not significantly different (p > 0.05). 3D-printed implant surgical guides without metal sleeve inserts enable accurate implant placement without exhausting the guide holes, rendering them feasible for fully guided implant placement.

Accuracy of Guided Implant Surgery in the Edentulous Jaw Using Desktop 3D-Printed Mucosal Supported Guides

Purpose: The aim of this in vitro study is to evaluate the accuracy of implant position using mucosal supported surgical guides, produced by a desktop 3D printer. Methods: Ninety implants (Bone Level Roxolid, 4.1 mm × 10 mm, Straumann, Villerat, Switzerland) were placed in fifteen mandibular casts (Bonemodels, Castellón de la Plana, Spain). A mucosa-supported guide was designed and printed for each of the fifteen casts. After placement of the implants, the location was assessed by scanning the cast and scan bodies with an intra-oral scanner (Primescan^®, Dentsply Sirona, York, PA, USA). Two comparisons were performed: one with the mucosa as a reference, and one where only the implants were aligned. Angular, coronal and apical deviations were measured. Results: The mean implant angular deviation for tissue and implant alignment were 3.25° (SD 1.69°) and 2.39° (SD 1.42°) respectively, the coronal deviation 0.82 mm (SD 0.43 mm) and 0.45 mm (SD 0.31 mm) and the apical deviation 0.99 mm (SD 0.45 mm) and 0.71 mm (SD 0.43 mm). All three variables were significantly different between the tissue and implant alignment (p < 0.001). Conclusion: Based on the results of this study, we conclude that guided implant surgery using desktop 3D printed mucosa-supported guides has a clinically acceptable level of accuracy. The resilience of the mucosa has a negative effect on the guide stability and increases the deviation in implant position.