Accuracy and complications using computer-designed stereolithographic surgical guides for oral rehabilitation by means of dental implants: a review of the literature

Accuracy of Full-Guided and Half-Guided Surgical Templates in Anterior Immediate and Delayed Implantation: A Retrospective Study

Computer-aided implantology has developed rapidly in recent years, this study aimed to compare the accuracy of guided-surgery between anterior immediate and delayed implantation, and simultaneously assess the effect of full-guided and half-guided templates on accuracy values. Seventy-six implants were inserted in 63 patients using full-guided or half-guided template in the anterior zone. Postoperative cone beam computed tomography (CBCT) was matched with preoperative planning to evaluate the deviation between actual and planned implants. No statistical difference was found in any deviation between immediate and delayed implantation (p > 0.05). In anterior immediate implantation, the global coronal, apical, depth and angular deviations of full-guided templates were all significantly lower than those of half-guided templates (0.66 ± 0.26 vs. 1.10 ± 0.76 mm, 0.96 ± 0.41 vs. 1.43 ± 0.70 mm, 0.46 ± 0.24 mm vs. 0.93 ± 0.79 mm and 1.69° ± 0.94° vs. 2.57° ± 1.57°). While in delayed implantation, full-guided templates only perform better with statistical significance on global apical and depth deviation (1.01 ± 0.42 vs. 1.51 ± 0.55 mm and 0.32 ± 0.26 vs. 0.71 ± 0.47 mm). After excluding the influence of depth deviation, the coronal and apical deviations between the two systems in immediate implantation and the apical deviations in delayed implantation had no statistical difference. Within the limit of this study, the results suggested the accuracy of guided-surgeries for anterior immediate and delayed implantations was comparable, and full-guided template was more accurate for immediate and delayed implantation.

Accuracy of 3D printed polymers intended for models and surgical guides printed with two different 3D printers

The purpose of the study was to evaluate the accuracy: trueness and precision of photopolymers used for dental models and surgical guides printed with two different digital light processing (DLP) printers. Forty specimens of four materials; E-dentstone^®, E-shell^®, NextDent™ Model, NextDent™ SG, and two designs; models A and B (n=5), were manufactured (DDDP, EvoDent). Trueness was evaluated by comparing values for 26 parameters with the CAD models' reference values and precision through standard deviation. The trueness and precision were higher for linear than for angle parameters. X- and Y-axes showed higher trueness than Z-axis and model B higher trueness than model A. The conclusions are; the accuracy is dependent on the design of the object. The linear precision appears to be high. The highest trueness was observed for a surgical guide polymer (NextDent™ SG). The definition of clinically relevant accuracy and acceptable production tolerance should be evaluated in future studies.

Targeted Endodontic Microsurgery: Implications of the Greater Palatine Artery

INTRODUCTION

Targeted Endodontic Microsurgery (TEMS) combines trephine burs and 3D-printed guides to make flapless maxillary palatal root-end surgery possible. This study assessed the location of the greater palatine artery (GPA), the relationship of the GPA to maxillary molar root ends, and the feasibility of flapless palatal-approach TEMS.

METHODS

Three endodontists analyzed 250 cone-beam computed tomographic images of maxillary molars for (1) transition morphology between the hard palate and the alveolar process adjacent to first and second molars as an indication of the most likely location of the GPA, (2) the superior-inferior relationship between the GPA and root ends, and (3) the feasibility of palatal-approach TEMS.

RESULTS

Palatal transition morphology included 20% Spine, 72% Bridge, and 8% Smooth. GPA position as related to palatal root ends was classified as 34% superior, 40% adjacent, and 21% inferior. Five percent of classifications were undefined. TEMS was deemed feasible for 47% of maxillary first molars and 52% of second molars, and was significantly more feasible with GPAs superior to palatal root ends. Reasons for infeasibility included GPA proximity and unfavorable resection angle or level. Maxillary first molar palatal roots were 11.13 ± 2.68 mm from the greater palatine foramen (GPF) and 2.37 ± 1.46 mm from the GPA. Second molar palatal roots were 4.94 ± 2.55 mm from the GPF and 2.53 ± 1.77 mm from the GPA.

CONCLUSIONS

Palatal transition morphology and GPA position adjacent to maxillary molars, as manifested in cone-beam computed tomographic coronal views, suggested maxillary palatal root TEMS could be accomplished with a 2-mm safety margin in 47% of first molars and 52% of second molars. Historical paradigms that do not consider flapless palatal surgical approaches may need to be revised.

Static computer-aided, partially guided, and free-handed implant placement: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To analyze the outcomes of static computer-aided implant placement (sCAIP) compared to partially guided (PGIP) and free-handed (FHIP) implant placement.

MATERIAL AND METHODS

This study was registered in PROSPERO (CRD42019131397). A comprehensive literature search was performed by two independent examiners. Only randomized controlled trials (RCTs) were selected. Treatment modalities included sCAIP, PGIP, and FHIP. Data pertaining to the outcomes of interest were extracted. Random-effects meta-analyses were feasible for a subset of outcomes.

RESULTS

From an initial list of 2,870 records, fourteen articles for a total of ten RCTs were selected. Data from 7 of these studies allowed for the conduction of three meta-analyses comparing accuracy of implant placement across modalities. Survival rate up to 12 months post-loading was high (>98%) and comparable between treatments (low-quality evidence). No tangible differences in terms of patient perception of intra- or postoperative discomfort were observed (low-quality evidence). Quantitative analyses revealed significantly lower angular (MD = 4.41°, 95% CI 3.99-4.83, p < .00001), coronal (MD = 0.65 mm, 95% CI 0.50-0.79, p < .00001), and apical (MD = 1.13 mm, 95% CI 0.92-1.34, p < .00001) deviation values for sCAIP as compared to FHIP (8 studies, 383 patients, 878 implants, high-quality evidence). A similar discrepancy, in favor of sCAIP, was observed for angular deviation only as compared to PGIP (MD = 2.11°, 95% CI 1.06-3.16, p < .00001).

CONCLUSIONS

sCAIP is associated with superior accuracy compared to PGIP and FHIP.

Accuracy of fully guided orthodontic mini-implant placement evaluated by cone-beam computed tomography: a study involving human cadaver heads

OBJECTIVES

The aim of this study was to evaluate the accuracy of fully guided orthodontic mini-implant (OMI) placements supported by tooth- (TBGs) or gingiva-borne silicone guides (GBGs) based on virtually superimposed lateral cephalograms on virtual plaster models.

MATERIALS AND METHODS

Lateral cephalograms and corresponding plaster models were virtually superimposed for the planning of OMI positions; fully guided TBGs and GBGs were fabricated (each, n = 10). A total of 40 OMIs were inserted in a paramedian position into the palate of 20 human cadavers. Postoperative cone-beam computer tomographies (CBCTs) were carried out, and an accuracy evaluation was performed by comparing preoperative planning models and postoperative CBCTs. Deviations of the axis, tip, centre of the shoulder and vertical position of each of the implants were evaluated. Furthermore, the transfer accuracy measured by postoperative CBCT scans were compared with the accuracy determined using an intraoral scanner.

RESULTS

A significant deviation between TBGs (2.81° SD 2.69) and GBGs (6.22° SD 4.26) regarding implant angulation was evaluated (p = 0.005). Implant tip and implant shoulder deviations revealed no statistical differences between the guides. Accuracy values of oral scans regarding vertical deviations were significantly more inaccurate when compared with CBCTs (p < 0.001).

CONCLUSIONS

The accuracy of an OMI position can be significantly increased by using a guide extension over the teeth. Vertical implant positions presented the lowest deviations. Postoperative oral scans and CBCTs represent diverging accuracy measurements when compared with virtual planning.

CLINICAL RELEVANCE

Users must keep in mind that despite virtual planning deviations, inaccuracies of a few millimetres may occur.

Narrative review regarding the applicability, accuracy, and clinical outcome of flapless implant surgery with or without computer guidance

Background

The advent of computer‐guided surgery removed the need for complex surgical interventions such as extensive flap elevations, second stage implant exposure, and complications usually associated with conventional protocols.

Purpose

(a) Analyze available literature reporting on applicability, accuracy, clinical outcome of flapless surgery with or without computer guidance. (b) Evaluate quality of studies, in terms of scientific level of evidence and ethical committee approval.

Materials and methods

A PUBMED search was performed in July 2018. A first search was based on a general search string limited to “Dental Implants” and “flapless surgery.” A second search focused on accuracy of computer‐guided surgery using search string “Surgery, Computer‐Assisted” or “guided surgery,” and “Dental implants.” The following inclusion criteria were applied: (a) studies in English; (b) human studies (excluding cadaver); (c) systematic reviews; (d) systematic reviews with meta‐analysis. Reviews not mentioning accuracy were excluded in search 2.

Results

Nine reviews included in total. Implant survival ranged between 89% and 100%. Early surgical and prosthetic complications reported in 9.1% to 36.4% of reviewed papers. Tooth‐supported guides show more accuracy than bone or mucosa‐supported guides. Fully guided surgery yields higher accuracy, with lower values for horizontal coronal, horizontal apical and angular deviation (1.00, 1.23, and 3.13°mm, respectively) than those placed with half guided surgery (1.44, 1.91, and 4.30 mm, respectively). Thirty‐four of 71 human studies included in nine reviews, mentioned ethical committee approval or compliance with Declaration of Helsinki.

Conclusions

Guided flapless surgery is comparable to free‐hand surgery in terms of implant survival, marginal bone remodeling, and peri‐implant variables. Clinicians advised to take care in all steps of the protocol, and include safety margins around virtually planned implants. Regarding compliance with research ethics, we should question whether scientific reports of clinical trials performed without an ethical umbrella are trustworthy. Compliance of ethics standards is imperative for submitted research papers.

The Effects of Distribution of Image Matched Fiducial Markers on Accuracy of Computer-Guided Implant Surgery

PURPOSE

Image registration of the optical intraoral scan to computed tomography image is essential for computer-guided implant surgery. The remaining teeth, which are considered to be congruent structures observed in the scan and radiographic images, are used to perform the image registration. The purpose of this study was to evaluate the effects of the distribution of matching fiducial points on the accuracy of the image registration.

MATERIALS AND METHODS

A partially edentulous model with three anterior remaining teeth was prepared. Two mini dental implants were inserted in the posterior edentulous areas on both sides, and computed tomography and surface scan data were obtained. Three groups were set according to the distribution of the image matching points used: localized distribution, unilateral distribution, and bilateral distribution. Fifteen graduate students performed the registration process in each group using the same image matching method. The accuracy of image registration was evaluated by measuring the geometric discrepancies between the radiographic and registered scan images in the anterior, middle, and posterior regions. One-way and two-way analysis of variance with the Tukey HSD post hoc test were used for statistical analysis (α = 0.05) RESULTS: In general, the registration discrepancy was lowest in the bilateral distribution group, followed by the unilateral distribution and localized distribution groups (p< 0.001). In the regional analysis, the registration error tended to increase as the measurement region moved farther from the matching points. The distribution of the matching points and measurement regions had a statistical interaction in the accuracy of image registration.

CONCLUSION

The accuracy of image registration of the surface scan to the computed tomography is affected by the matching point distribution that can be improved by placing artificial markers in the edentulous areas.

Stereolithographic Surgical Guide with a Combination of Tooth and Bone Support: Accuracy of Guided Implant Surgery in Distal Extension Situation

A distal free-end situation could result in insufficient stability of the surgical guide, and could reduce accuracy of the static guided implant surgery (sGIS). The purpose of this study was to investigate the accuracy of sGIS using a combination tooth-and-bone supported stereolithographic (SLA) surgical guide in distal extension situation. Thirty dentists, each placed three implants at the Federal Dentaire Internationale (FDI) teeth positions #46, #47 (a distal extension situation), and #36 (a single tooth gap) via the surgical guide on a model fixed to a manikin. Pre- and post-operative computed tomography (CT) images of the models were superimposed, and the positional and angular deviations of the implants were measured with metrology software. An analysis of variance (ANOVA) test was performed to evaluate the intergroup differences. No significant differences were found for all the positional and angular deviations among the three implant sites, except the bucco-lingual deviation at the implant platform in the #47 position (0.43 ± 0.19 mm) that was significantly larger than the #46 (0.21 ± 0.14 mm) and #36 (0.24 ± 0.25 mm) positions (p < 0.0001). Within the limits of this study, we conclude that, in distal extension situation of missing mandibular molars, adding a bone-supported strut in the distal part of the surgical guide can be beneficial to the accuracy of the sGIS.

2D/3D accuracies of implant position after guided surgery using different surgical protocols: A retrospective study

PURPOSE

To compare the 2D and 3D positional accuracy of four guided surgical protocols using an analysis of linear and angular deviations.

METHODS

DICOM and .STLs files obtained from a CBCT and a digital impression were superimposed with software to plan implant position. Fifty-six patients were subdivided into 4 groups: FGA group (template support [Ts]: teeth [T]; bed preparation [Bp]: fully guided [FG]; implant insertion [Ii]: 3D template [3Dt]; device [D]: manual adapter [MA], FGM group (Ts: T; Bp: FG; Ii: 3Dt; D: fully guided mounter [FGM]), PG group (Ts: T; Bp: FG; Ii: manual; D: none) and MS group (Ts: mucosa; Bp: FG; Ii: 3Dt; D: FGM). The position of 120 implants was assessed by superimposing the planned and final position recorded with a digital impression.

RESULTS

In FGA group, 3D deviations were 0.92 ± 0.52 mm at the implant head and 1.14 ± 0.54 mm at the apex, and the angular deviation (ang. dev.) was 2.45 ± 1.24°. In FGM group, were 0.911 ± 0.44 mm (head) and 1.11 ± 0.54 mm (apex), and the ang. dev. was 2.73 ± 1.96°. In PG group, were 0.95 ± 0.47 mm (head) and 1.17 ± 0.488 mm (apex), and the ang. dev. was 3.71 ± 1.67°. In MS group, were 1.15 ± 0.45 mm (head) and 1.42 ± 0.45 mm (apex), and the ang. dev. was 4.19 ± 2.62°. Ang. dev. of MS group was different from the other groups (P < 0.05).

CONCLUSIONS

Guided surgery showed a sufficient accuracy.

[Research advances in the use of digital surgical guides in implantology]

Dental implants have become the main choice for patients to fill in their missing teeth. A precise placement is the basis for a functional and aesthetic restoration. A digital surgical guide is a carrier that transfers the preoperative plan of dental implants to the actual surgery. This paper provides some references that can help clinicians improve the accuracy of implant surgery by stating the development, classification, advantages and disadvantages, and factors that affect the accuracy of digital guides.

Effects of disinfection and sterilization on the dimensional changes and mechanical properties of 3D printed surgical guides for implant therapy - pilot study

Background

The purpose of this research was to investigate the effects of disinfection and three different sterilization methods on the dimensional changes and mechanical properties of three-dimensional (3D) printed surgical guide for implant therapy. The objective was to assess the effects of sterilization procedures in 3D printed drill guide templates with destructive and non-destructive material testing.

Methods

Fifteen identical drill guide templates were produced using a 3D printer. The surgical guides were classified into five groups: three controls, three disinfected (4% Gigasept®, 60 min), three plasma sterilized, three autoclave sterilized (+ 1 bar, 121 °C, 20 min), and three autoclave sterilized (+ 2 bar, 134 °C, 10 min).

The templates were digitalized with a Steinbichler SCAN ST 3D scanner. Length was measured under an SZX16 stereomicroscope. A scanning electron microscope was used to study the surface morphology of the drill templates. The hardness, and flexural and compressive strength were measured to assess any changes in the physical characteristics of the material caused by sterilization. The drill guide templates were also examined with a Dage XiDAT 6600 X-ray. During the X-ray examinations, the following parameters were used: 100 kV voltage, 128 AVG averaging, 0.8 W power. One-way analysis of variance (ANOVA) was used to detect the difference between groups.

Results

Evaluation of the hardness measurements of the various specimens shows that the hardness of the material was not changed by the plasma sterilization (p = 0.0680), steam sterilization on 121 °C (p = 0.6033) or disinfection process (p = 0.1399). The statistical analysis revealed significant difference in hardness strength of the autoclave sterilized (134 °C) specimens (p = 0.0002). There was no significant difference between the goups regarding the scanning electron microscopic and stereomicroscopic examinations. There was no significant difference regarding the X-ray visibility of the templates to the effect of the disinfection (p = 0.7844), plasma sterilization (p = 0.4091) and steam sterilization on 121 °C (p = 0.9277) and steam sterilization on 131 °C (p = 0.093). The effect of the sterilization was the same in case of both flexural and compressive strength of the material.

Conclusions

Our findings indicate that plasma sterilization and steam sterilization at 121 °C were both suitable for sterilizing the tested 3D printed surgical guides.

Guided implant surgery risks and their prevention

Ideal implant placement may reduce surgical complications, such as nerve injury and lingual cortical plate perforation, and minimize the likelihood of functional and prosthetic compromises. Guided implant surgery (GIS) has been used as the means to achieve ideal implant placement. GIS refers to the process of digital planning, custom-guide fabrication, and implant placement using the custom guide and an implant system-specific guided surgery kit. GIS includes numerous additional steps beyond the initial prosthetic diagnosis, treatment planning, and fabrication of surgical guide. Substantial errors can occur at each of these individual steps and can accumulate, significantly impacting the final accuracy of the process with potentially disastrous deviations from proper implant placement. Pertinent overall strategies to reduce or eliminate these risks can be summarized as follows: complete understanding of the possible risks is fundamental; knowledge of the systems and tools used is essential; consistent verification of both diagnostic and surgical procedures after each step is crucial; proper training and surgical experience are critical. This review article summarizes information on the accuracy and efficacy of GIS, provides insight on the potential risks and problems associated with each procedural step, and offers clinically relevant recommendations to minimize or eliminate these risks.

Accuracy of guided implant surgery: an experimental set-up

BACKGROUND

The aim of the study was to evaluate the opportunities of guided implant surgery compared to conventional implant surgery.

METHODS

For this purpose 7 mandibles were prepared, which were sectioned in order to have an edentulous area. Seven half-mandibles were assigned to guided implant surgery group (test) and an equal number to conventional surgery group (control).

RESULTS

The results of the test group were as follows: mean vertical implant level discrepancy 0.44±0.29 mm, buccolingual implant position discrepancy 1.31±0.65 mm, mesio-distal implant position discrepancy 0.68±0.42 mm, implant apex discrepancy 1.92±0.92 mm, mean distance between the two fixtures 0.26±0.19 mm. The results of the control group are as follows: mean vertical implant level discrepancy 1.1±0.4 mm, mean bucco-lingual implant position discrepancy 2.14±0.89 mm, mean mesio-distal implant position discrepancy 1.7±0.79 mm, mean implant apex discrepancy 2.91±0.50 mm, mean distance between the two fixtures 0.78±0.63 mm.

CONCLUSIONS

Within the limitations of an experimental set up, the results may demonstrate how the use of guided implant surgery may be a valid help for the clinician for a more accurate and safe implant placement.

Distribution of Trabecular Bone Density in the Maxilla and Mandible

INTRODUCTION

Implant osseointegration is strongly influenced by the bone quality at the implant insertion site. The present work aims to create distribution diagrams showing the average bone density at each position within the jaws.

MATERIALS AND METHODS

Data were retrospectively collected from 4 oral surgeons who sought bone-density measurements during implant placement using a torque-measuring implant micromotor. Statistical analyses were performed to investigate whether bone density correlated with the patients' sex and age and whether the bone-density values at different positions within each arch correlated to each other.

RESULTS

Records of 2408 patients and 6060 bone-density readings were retrieved, and density distribution diagrams were created. Density values showed a significant variation within subjects. Within the same jaw, density between adjacent positions showed significant differences. Density at a given position correlated significantly with that at the other positions in most cases. Bone density was significantly lower in women than in men; no significant correlation was found between bone density and the patient age.

CONCLUSIONS

Bone density of patients displays significant interindividual variation, thus meaningful assessment must be conducted on a patient-by-patient basis.

Minimal invasive microscopic tooth preparation in esthetic restoration: a specialist consensus

By removing a part of the structure, the tooth preparation provides restorative space, bonding surface, and finish line for various restorations on abutment. Preparation technique plays critical role in achieving the optimal result of tooth preparation. With successful application of microscope in endodontics for >30 years, there is a full expectation of microscopic dentistry. However, as relatively little progress has been made in the application of microscopic dentistry in prosthodontics, the following assumptions have been proposed: Is it suitable to choose the tooth preparation technique under the naked eye in the microscopic vision? Is there a more accurate preparation technology intended for the microscope? To obtain long-term stable therapeutic effects, is it much easier to achieve maximum tooth preservation and retinal protection and maintain periodontal tissue and oral function health under microscopic vision? Whether the microscopic prosthodontics is a gimmick or a breakthrough in obtaining an ideal tooth preparation should be resolved in microscopic tooth preparation. This article attempts to illustrate the concept, core elements, and indications of microscopic minimally invasive tooth preparation, physiological basis of dental pulp, periodontium and functions involved in tool preparation, position ergonomics and visual basis for dentists, comparison of tooth preparation by naked eyes and a microscope, and comparison of different designs of microscopic minimally invasive tooth preparation techniques. Furthermore, a clinical protocol for microscopic minimally invasive tooth preparation based on target restorative space guide plate has been put forward and new insights on the quantity and shape of microscopic minimally invasive tooth preparation has been provided.

Accuracy of Computer-Guided Template-Based Implant Surgery: A Computed Tomography-Based Clinical Follow-Up Study

OBJECTIVE

The aim of this clinical study was to analyze the accuracy of computer-guided implant surgery.

MATERIALS AND METHODS

Assisted by computed tomography (CT)-based planning software and navigational templates, 16 patients successfully received 26 dental implants. Each implant parameter (a-d) was calculated based on superimposed preoperative and postoperative cone beam CT scans: (a) deviation at entry point; (b) deviation at apex; (c) angular deviation; and (d) depth deviation.

RESULTS

Mean central deviation at implant entry point and apex was 0.91 mm (standard error [SE] = 0.11 mm; 95% confidence interval [CI]: 0.69-1.13) and 1.22 mm (SE = 0.11 mm; 95% CI: 0.99-1.45), respectively. Mean angulation deviation was 4.11 degrees (SE = 0.52 degrees; 95% CI: 3.04-5.17) and the average depth deviation was 0.65 mm (SE = 0.11 mm; 95% CI: 0.42-0.87). For the total number of implants placed, the maximum error was 2.34 mm at entry point, 2.71 mm at apex, 9.44 degrees in angular deviation, and 2.00 mm in depth deviation.

CONCLUSION

Great accuracy was reached even in advanced cases with prior bone augmentation and complex traumas. This leads to the conclusion that particularly in advanced cases, computer-guided implantation can be beneficial.

Influence of surgical guide support and implant site location on accuracy of static Computer-Assisted Implant Surgery

OBJECTIVE

To investigate the effect of surgical guide support and implant site location on the accuracy of static Computer-Assisted Implant Surgery (sCAIS) in partially edentulous patients.

MATERIALS AND METHODS

375 replica implants were inserted in 85 study models. Surgical implant placement was done using static 3D printed surgical guides, which were designed to be supported either by all the teeth present in the model (full arch), or by 4-teeth), 3-teeth or 2-teeth. Each study model included three single-tooth gap (STG) situations; one extraction socket site and two implants placed in a distal extension situation. Preplanned and postoperative implant positions were compared using the treatment-evaluation tool in digital software. 3-dimensional and angular deviations were measured. Statistical analysis was done using ANOVA, and pairwise t tests and Bonferroni-Holm's adjustment were applied as a post hoc test.

RESULTS

Accuracy of surgical guides used in sCAIS was significantly affected by the number and type of teeth used for its support. Guides supported by 4 teeth were not significantly different from accuracy of full-arch-supported guides (p > .05). Guide support by posterior teeth was associated with an increased level of accuracy, when compared to anterior teeth guide support. Implants placed in extraction sockets were associated with significantly higher 3D and angular deviation values (p < .05), and surgical guides with a distal extension situation resulted in significantly higher deviation values (p < .05).

CONCLUSION

The number and location of teeth supporting the surgical guide can significantly influence the accuracy of sCAIS, with 4 teeth providing equal accuracy to full-arch guides in (STG) situations.

Augmented reality for dental implantology: a pilot clinical report of two cases

BACKGROUND

Despite the limited number of articles dedicated to its use, augmented reality (AR) is an emerging technology that has shown to have increasing applications in multiple different medical sectors. These include, but are not limited to, the Maxillo-facial and Dentistry disciplines of medicine. In these medical specialties, the focus of AR technology is to achieve a more visible surgical field during an operation. Currently, this goal is brought about by an accurate display of either static or dynamic diagnostic images via the use of a visor or specific glasses. The objective of this study is to evaluate the feasibility of using a virtual display for dynamic navigation via AR. The secondary outcome is to evaluate if the use of this technology could affect the accuracy of dynamic navigation.

CASE PRESENTATION

Two patients, both needing implant rehabilitation in the upper premolar area, were treated with flapless surgery. Prior to the procedure itself, the position of the implant was virtually planned and placed for each of the patients using their previous scans. This placement preparation contributed to a dynamic navigation system that was displayed on AR glasses. This, in turn, allowed for the use of a computer-aided/image-guided procedure to occur. Dedicated software for surface superimposition was then used to match the planned position of the implant and the real one obtained from the postoperative scan. Accuracies, using this procedure were evaluated by way of measuring the deviation between real and planned positions of the implants. For both surgeries it was possible to proceed using the AR technology as planned. The deviations for the first implant were 0.53 mm at the entry point and 0.50 mm at the apical point and for the second implant were 0.46 mm at the entry point and 0.48 mm at the apical point. The angular deviations were respectively 3.05° and 2.19°.

CONCLUSIONS

From the results of this pilot study, it seems that AR can be useful in dental implantology for displaying dynamic navigation systems. While this technology did not seem to noticeably affect the accuracy of the procedure, specific software applications should further optimize the results.

Computer-Guided Dental Implant Treatment of Complete Arch Restoration of Edentulous and Terminal Dentition Patients

The treatment of completely edentulous or soon-to-be completely edentulous dental arches with complete-arch fixed denture restorations, supported by dental implants, are some of the more complicated patient cases in oral and maxillofacial surgery and prosthodontics. This article discusses the use of digital technologies, computerized tomographic (CT) guided planning software applications, and surgical guides in treating these complex dental implant patient cases. A discussion of the nuances and workflows of different types of treatments are provided. The importance of experience and a multi-disciplinary team approach is emphasized.

Comparison of postoperative intraoral scan versus cone beam computerised tomography to measure accuracy of guided implant placement-A prospective clinical study

OBJECTIVE

To evaluate the accuracy of implant placement with a digitally planned guided implant procedure. Two methods for identifying the actual postoperative positioning of the implants were compared: CBCT and IO scanning.

MATERIAL AND METHODS

Twenty-eight implants with a sandblasted and acid-etched surface were placed in thirteen patients using tooth-supported surgical guides following a digital planning procedure. The implants were submerged for 12-15 weeks. New CBCT images were taken for identification of the implant position. After second stage surgery, scan bodies were mounted on the implants and scanned with an IO digital scanner. The recordings from the CBCT images and the IO scans were compared with respect to the identified positions of the implants.

RESULTS

The study did not resolve any significant differences of the identified positioning of the implants as measured by CBCT or IO, except for the apical deviations at the coronal and apical points. The angular difference between CBCT and IO scanning at the coronal point was -0.011 (±0.6) degrees, whereas the 3D deviation was 0.03(±0.17) mm. The distal deviation between CBCT and IO scanning was 0.01(± 0.16) mm, and the vestibular deviation 0.033(± 0.16) mm and the apical deviation difference was 0.09(± 0.16) mm. The 3D deviation at the apical point was 0.04(± 0.22) mm. The distal deviation between CBCT and IO scanning was 0.06(± 0.19) mm, and the vestibular deviation 0.032(± 0.23) mm and the apical deviation difference was 0.09(± 0. 16) mm.

CONCLUSION

The study demonstrated that accuracy measurements using IO scanning yields comparable results to those obtained by CBCT.

Is Digital Guided Implant Surgery Accurate and Reliable?

The digital workflow for computer-aided implant surgery includes a range of steps leading to generation of a prosthetically driven, 3-dimensional virtual plan, which is transitioned into the patient's mouth by the surgical guide and protocol. Guided implant surgery is believed to be accurate and reliable compared with free-handed implant surgery. However, deviation between implant virtual plan and implant real position may occur as a result of accumulated errors throughout the digital workflow. This article reviews the digital workflow of static computer-aided implant surgery. Factors that may affect the accuracy and clinical outcome of the guided surgery are also reviewed.

The Accuracy of Computer-Assisted Implant Surgery Performed Using Fully Guided Templates versus Pilot-Drill Guided Templates

Purpose. Computer-assisted stereolithographically guided surgery allows an ideal implant placement for prosthetic restoration. Two types of stereolithographic templates are currently available: a fully guided template and a pilot-drill guided template. The purpose of this study was (i) to evaluate the accuracy of implant insertion using these types of surgical templates and (ii) to define parameters influencing accuracy. Materials and Methods. 20 patients were enrolled and divided into 2 study groups: in group A, implants were placed using CAD-CAM templates with fully guided sleeves; in group B, implants were placed with a template with only pilot-drill guided sleeves. Pre- and postoperative computed tomographies were used to measure differences between final positions of implants and virtually planned positions. Three linear discrepancies (coronal, apical, and depth) and two angular ones (buccolingual and mesiodistal) were measured. Correlations between accuracy and jaws of interest, implant length and diameters, and type of edentulism were also analysed. Results. A total of 50 implants were inserted in 15 patients using CAD-CAM templates: 23 implants in group A and 27 in group B. The mean coronal deviations were 1.16 and 1.11 mm (P = 0.35), respectively; the mean apical deviations were 1.65 and 1.71 mm (P = 0.22); the mean depth deviations were 0.95 and −0.68 mm (P = 0.032); the mean buccolingual angular deviations were 4.16° and 6.72° (P = 0.042); and the mean mesiodistal ones were 2.81° and 5.61° (P = 0.029). In addition, the accuracy was statistically influenced only by implant diameter for coronal discrepancy (P = 0.035) and by jaw of interest for mesiodistal angulation (P = 0.045). Conclusion. Fully guided implant surgery was more accurate than pilot-drill guided surgery for different parameters. For both types of surgery, a safety margin of at least 2mm should be preserved during implant planning to prevent damage to nearby anatomical structures.

Reliability and accuracy of skin-supported surgical templates for computer-planned craniofacial implant placement, a comparison between surgical templates: With and without bony fixation

INTRODUCTION

The purpose is to determine the accuracy of guided implant placement in the orbital, nasal, and auricular region using computer-aided designed stereolithographic skin-supported surgical templates with and without bone fixation pins.

MATERIALS AND METHODS

Preoperatively, cone-beam CT (CBCT) and multiple detector computed tomography (MDCT) scans were acquired from 10 cadaver heads, followed by virtual planning of implants in the orbital margin, auricular region and nasal floor. Surgical skin-supported templates were digitally designed to allow flapless implant placement. Fixation pins were used for stabilization comprising half of all templates in predetermined bone areas. The accuracy of the surgical templates was validated by comparing the achieved implant location to its virtual planned implant position by calculating the linear and angular deviations.

RESULTS

Surgical templates with the use of bone fixation pins produced statistically significant greater implant deviations as compared to the non-fixated surgical templates.

CONCLUSION

The results of this study indicate that significant deviation has to be taken into account when placing cranio-maxillofacial implants using skin-supported surgical templates. Surprisingly, the use of bone-fixated pins worsened the accuracy.

Consideration for Contemporary Implant Surgery

The advancement of technology often provides clinicians and patients better clinical alternatives to achieve optimal treatment outcomes. Computer-guided options allow clinicians to realize the virtual prosthodontically driven surgical plan, facilitating more predictable implant placement. Although the use of technology does not mean the clinicians can forgo the fundamental treatment principles when treating a patient, proper assessment and diagnostic approach from prosthodontic, surgical, and radiographic perspectives are still essential for a successful clinical outcome. The purpose of this article is to review the fundamental concepts for the use of computer-guided surgery to facilitate prosthodontic treatment.

Accuracy of computer-guided implant placement in anterior regions

STATEMENT OF PROBLEM

Implant placement in the anterior regions is often challenging because of limited space and bone volume availability.

PURPOSE

The purpose of this clinical study was to investigate the accuracy of computer-guided surgery with a long drill key to place implants in the anterior regions.

MATERIAL AND METHODS

Computer-guided implant surgery was performed for 32 participants requiring implants in anterior regions. The procedure involved using a 12-mm-long drill key to guide the 2.0-mm-diameter drill. Deviations between the planned and actual implant positions were evaluated by using cone beam computed tomography (CBCT) scans obtained before and after surgery. A t test was used for comparisons between the planned and placed implants and to determine the influence of the arch (maxilla/mandible) and time (immediate/delayed) on accuracy.

RESULTS

A total of 40 implants (20 implants in the maxilla and 20 implants in the mandible) were placed. The mean linear deviation was 0.46 mm (range, 0 to 1.15 mm) for the implant shoulder and 0.67 mm (range, 0.14 to 1.19 mm) for the implant apex. The mean angular deviation was 1.40 degrees (range, 0.30 to 2.57 degrees). The mean depth deviation was 0.15 mm (range, 0.10 to 0.82 mm).

CONCLUSIONS

This clinical study showed that the accuracy of computer-guided implant placement may be enhanced by using a long drill key and may thus enable more accurate implant placement in anterior regions.

Long-term clinical outcome of single implants inserted flaplessly or conventionally

BACKGROUND

Flapless implant surgery is mostly performed using guided surgical protocols, however, long-term studies on free-handed flapless surgery for single implants are lacking.

PURPOSE

This prospective study evaluates bone level changes, peri-implant health, and complications of solitary implants placed using a conventional flap (F) or flaplessly (FL) after 6-9 years.

MATERIALS AND METHODS

Fifty-three single TiUnite Brånemark implants were originally inserted in 49 patients using an one-stage delayed loading protocol with flap (n = 27, F) or flaplessly (n = 26, FL) based on available bone volume and surgeon's decision-making. Thirty-six patients with 37 implants participated in the prospective follow-up investigation 6-9 years later whereby survival, bone level changes, peri-implant health, and complications were assessed.

RESULTS

After 88 months (range 76-107), all implants were survived. For F and FL combined, the overall average radiographic bone level was above the first implant thread, 1.26 mm apical of the implant-abutment junction (SD 1.08; 0-4.9) and statistically comparable. Bone loss from time of loading was 0.49 mm (SD 1.1; -1.3 to 2.8) for F and -0.89 mm (SD 1.0; -2.8 to 0.7) for FL (P < .01), suggesting regrowth of bone in FL due to initial countersinking. One implant (2.7%) had a probing depth above 5 mm.

CONCLUSION

Free-handed flapless implant surgery for single implants with neighboring teeth is a predictable long-term treatment provided when there is sufficient bone volume.

Real Versus Virtual Position of Single Implants Installed in Premaxilla via Guided Surgery: A Proof of Concept Analyzing Positional Deviations

The aim of this research letter was to report the results of a pilot study designed to compare the real and virtual position of implants placed using computer-guided flapless implant surgery for single restorations in the premaxilla. A total of 8 patients (2 men and 6 women) with a mean age of 40 years old (range: 32-73 years) had a total of 11 implants inserted using a tooth-supported stereolithographic guide. After implant placement, the positions (coronal, central, and apical) and angulation of the implants installed in relation to those planned were determined via the superposition of pre- and postoperative 3-dimensional models using Dental Slice software (Bioparts, Brasília, Brazil). The mean angular deviation was 2.54° ± 0.71°. The deviations found for the coronal, central, and apical positions were 1.3 ± 0.77 mm, 1.49 ± 0.58 mm, and 2.13 ± 1.32 mm, respectively.

Novel electrical conductivity device for osteotomy preparation for dental implants placement: A cadaver study

OBJECTIVES

To evaluate the accuracy, safety, and anticipation effect of a novel electrical conductivity device (SG) in maxillary osteotomy preparation for placement of dental implants.

MATERIALS AND METHODS

Thirty-seven osteotomies were prepared by three operators with different levels of expertise, using the SG protocol in the maxilla of six fresh frozen cadavers. A pre-op CT measurement of the length of bone in the desired implant location was taken and compared with the final length of the osteotomy created using SG during surgery. A comparison was made between the results of the different operators.

RESULTS

The pre-op CT bone length measurements and the final depth assessment of the osteotomy with SG had a very high correlation level (0.977) with a significant mean difference of 0.639 mm (P < .0001), with the pre-op CT measurements being longer. The least experienced operator had placed the implants 0.924 mm less deep than the pre-op CT length measurements while the most experienced operator had placed the implants 0.244 mm less deep than the pre op CT length measurements. All implants were placed in the correct position and no breach of the sinus/nasal floor or buccal/palatine bone plates was detected.

CONCLUSIONS

The SG electrical conductivity device offers the operator real-time monitoring during the surgical procedure. It provides a simple, safe, and sensitive method of detecting breaches, making it simple and safe for oral surgeons with different levels of expertise to use, with promising results.

Flapless dental implant surgery and use of cone beam computer tomography guided surgery

Flapless implant surgery is increasing in popularity, particularly due to advances and increased usage of cone beam computed tomography (CBCT) and dental implant treatment planning software allowing three-dimensional assessment of the implant site. It is the aim of the article to provide an overview of flapless implant surgery and CBCT guided flapless implant surgery and summarise the literature with regard to the effectiveness of this surgical technique.

Bimaxillary simultaneous immediate loading of full-arch restorations: A case series

Aim

To describe a bimaxillary simultaneous immediate loading protocol with full-arch implant-supported fixed prostheses.

Material and Methods

A prospective case series of 8 patients who required full-arch rehabilitation was conducted. The main inclusion criteria were patients with teeth that required extraction. At least 1 molar per arch was temporarily employed to stabilize the surgical template and the provisional prosthesis during intraoral relining.

Results

Two upper implants failed in 1 patient. Structural fracture was registered in 3 patients, around 3 months after loading. All of them had bruxism. Three esthetic complications were registered: midline deviation, canting of the oclusal plane and color mismatch.

Conclusions

Although this protocol achieves optimal results, some mechanical complications were encountered. The fracture of the provisional prosthesis is a relatively common mechanical complication but does not seem to jeopardize the final treatment result.

Key words:Implant-supported full-arch, provisional prosthesis fracture, bimaxillary simultaneous rehabilitation, conical abutments.

Three-dimensional computer-guided implant placement in oligodontia

Background

The aim of computer-designed surgical templates is to attain higher precision and accuracy of implant placement, particularly for compromised cases.

Purpose

The purpose of this study is to show the benefit of a full three-dimensional virtual workflow to guide implant placement in oligodontia cases where treatment is challenging due compromised bone quantity and limited interdental spaces.

Patient and methods

A full, digitalized workflow was performed for implant placement in two oligodontia patients. Accuracy was assessed by calculating the coordinates of the entry point (shoulder) and apex (tip) as well as the angular deviation of the planned and actual implants.

Results

Implant placement could be well performed with the developed computer-designed templates in oligodontia. Mean shoulder deviation was 1.41 mm (SD 0.55), mean apical deviation was 1.20 mm (SD 0.54) and mean angular deviation was 5.27° (SD 2.51).

Conclusion

Application of computer-designed surgical templates, as described in this technical advanced article, aid in predictable implant placement in oligodontia where bone quantity is scarce and interdental spaces are limited.

Current and emerging applications of 3D printing in medicine

Three-dimensional (3D) printing enables the production of anatomically matched and patient-specific devices and constructs with high tunability and complexity. It also allows on-demand fabrication with high productivity in a cost-effective manner. As a result, 3D printing has become a leading manufacturing technique in healthcare and medicine for a wide range of applications including dentistry, tissue engineering and regenerative medicine, engineered tissue models, medical devices, anatomical models and drug formulation. Today, 3D printing is widely adopted by the healthcare industry and academia. It provides commercially available medical products and a platform for emerging research areas including tissue and organ printing. In this review, our goal is to discuss the current and emerging applications of 3D printing in medicine. A brief summary on additive manufacturing technologies and available printable materials is also given. The technological and regulatory barriers that are slowing down the full implementation of 3D printing in the medical field are also discussed.