Three-Dimensional Accuracy of Guided Implant Placement: Indirect Assessment of Clinical Outcomes

Does curve of Spee affect the precision of 3D-printed curvature-adaptive splints?

OBJECTIVES

This study aimed to propose a standardized protocol for the fabrication of three-dimensionally (3D)-printed curvature-adaptive splints (CASs) and assess the precision of CASs on dentitions with different depths of the curve of Spee (COS).

METHODS

76 lower dental resin models, each exhibiting one of the four types of COS (0-, 2-, 4-, and 6-mm deep), were selected and digitally scanned. CASs were designed, 3D printed, and grouped into C0, C2, C4, and C6, corresponding to the four types of COS depths. To assess precision, the CASs occluded with the resin model were scanned as a whole and compared with the originally designed ones.

RESULTS

In terms of translational deviations observed in the CASs, the mean value of absolute sagittal deviation (0.136 mm) was significantly higher than those of vertical (0.091 mm) and transversal deviations (0.045 mm) (P < 0.01). Regarding rotational deviations of the CASs, the mean deviation in pitch (0.323°) was significantly higher than those in yaw (0.083°) and roll (0.110°) (P < 0.01). However, when comparing the accuracy of CASs across C0, C2, C4, and C6 groups, no statistically significant difference was found. Additionally, the translational deviations, rotational deviations, and RMSE of all groups were significantly lower than the clinically acceptable limits of 0.5 mm, 1°, and 0.25 mm, respectively (P < 0.01).

CONCLUSIONS

The depth of the COS has no significant impact on the precision of CASs, as evidenced by the absence of statistically significant differences in translational, rotational deviations, and RMSE among all groups (C0, C2, C4, and C6). Moreover, despite relatively high deviations in the sagittal dimension and pitch, all dimensional deviations and RMSE remained statistically significantly lower than the corresponding clinically acceptable limits (CALs) in all groups.

CLINICAL SIGNIFICANCE

This standardized protocol incorporating "curvature-adaptation" represents an optimized approach to fabricating diverse 3D-printed splints tailored to dentitions with different anatomical features in contemporary digital dentistry.

Comparison of Different Types of Static Computer-Guided Implant Surgery in Varying Bone Inclinations

This research aimed to compare the accuracy of dental implant placement among three types of surgical guide: metal sleeve with key handle (Nobel guide, Nobel Biocare, Göteborg, Sweden), metal sleeve without key handle, and non-sleeve without key handle (Dentium full guide kit, Dentium Co., Seoul, Korea) when placing the implant in different bone inclinations. A total of 72 polyurethane bone models were fabricated in different inclinations (0°, 45°, and 60°). The dental implants were placed in bone models following the company’s recommendations. After dental implants were installed, the digital scans were done by an extraoral scanner. The deviations of the dental implant position were evaluated by superimposition between post-implant placement and reference model by using GOM inspect software. The deviation measurement was shown in 5 parameters: angular deviation, 3D deviation at the crest, 3D deviation at the apex, lateral linear deviation, and vertical linear deviation. The data were analyzed using One-way ANOVA and post-hoc tests at a significance level of 0.05. The accuracy of the dental implant position was not significantly influenced by the difference in the surgical guide system (p > 0.05). There were significant differences between placed and planned implant positions in the different inclinations of the bone. A significant difference was found in all parameters of 0° and 60° bone inclinations (p < 0.05). At 0° and 45°, angulated bone showed significant differences except in 3D deviation at the apex. Between 45° and 60° were significant differences only in angular deviation. Within the limitations of this study, the accuracy of implant placement among three types of surgical guides (Non-sleeve without key handle, Metal sleeve without key handle, and Metal sleeve with key handle) from two companies (Dentium and Nobel Biocare) was similar. Hence, the operators can choose the surgical guide system according to their preference. The inclination of bone can influence the angulation of dental implants.

Virtual extensions improve perception-based instrument alignment using optical see-through devices

Instrument alignment is a common task in various surgical interventions using navigation. The goal of the task is to position and orient an instrument as it has been planned preoperatively. To this end, surgeons rely on patient-specific data visualized on screens alongside preplanned trajectories. The purpose of this manuscript is to investigate the effect of instrument visualization/non visualization on alignment tasks, and to compare it with virtual extensions approach which augments the realistic representation of the instrument with simple 3D objects. 18 volunteers performed six alignment tasks under each of the following conditions: no visualization on the instrument; realistic visualization of the instrument; realistic visualization extended with virtual elements (Virtual extensions). The first condition represents an egocentric-based alignment while the two other conditions additionally make use of exocentric depth estimation to perform the alignment. The device used was a see-through device (Microsoft HoloLens 2). The positions of the head and the instrument were acquired during the experiment. Additionally, the users were asked to fill NASA-TLX and SUS forms for each condition. The results show that instrument visualization is essential for a good alignment using see-through devices. Moreover, virtual extensions helped achieve the best performance compared to the other conditions with medians of 2 mm and 2° positional and angular error respectively. Furthermore, the virtual extensions decreased the average head velocity while similarly reducing the frustration levels. Therefore, making use of virtual extensions could facilitate alignment tasks in augmented and virtual reality (AR/VR) environments, specifically in AR navigated surgical procedures when using optical see-through devices.

The implant position accuracy between using only surgical drill guide and surgical drill guide with implant guide in fully digital workflow: a randomized clinical trial

BACKGROUND

To evaluate and compare accuracy in position and inclination of a single-tooth implant placement using tooth-supported surgical drill guide (SDG) and surgical drill guide with implant insertion guide (SDIG) in fully digital workflow.

MATERIALS AND METHODS

Thirty partially single edentulous patients were recruited. After randomization, participants were divided into 2 groups equally. The first group underwent implant placement through SDG only, while the second group was subjected to SDIG. All procedure proceeded under a fully digital workflow as the combination of digital scanning from an intraoral scanner, 3D radiographic images from cone-beam computed tomography (CBCT), implant planning software, and a 3D manufacturing machine. A post-operative CBCT was performed to compare the deviations (7 parameters) between planned and actual implant positions.

RESULTS

The mean global deviations at the shoulder and apex were 0.74 ± 0.36 and 1.29 ± 0.61 mm, respectively in the SDG group and 0.48 ± 0.22 mm and 0.71 ± 0.31 mm, respectively in the SDIG group. Likewise, the other parameters in the SDIG group showed fewer deviations than SDG for all measurements. Statistically significant differences were indicated by all parameters except for the horizontal deviation at the implant shoulder (p < .05).

CONCLUSION

In single-tooth implant placement with a tooth-supported guide using a computer-assisted (static) system with the SDIG could reduce deviations of actual implant position when compared with using SDG only. Besides, guided implant surgery by fully digital workflow is a practical procedure and provides precise implant position regarding the prosthetic-driven concept.

Multivariate analysis of causal factors influencing accuracy of guided implant surgery for partial edentulism: a retrospective clinical study

Abstract

Background

In dental implant treatment, the placement position of the implant body is important. The hypothesis is that there are factors that have a greater impact than the factors that have been studied so far.

Material and Methods

The deviation between planned and actually placed implants was measured three-dimensionally by modified treatment evaluation method in 110 patients who underwent implant placement with guided surgery for partial edentulism. Ten factors that seemed to affect errors in placement were selected: the type of tooth, type of edentulism, distance from the remaining teeth, the type of implant, implant length, number of implants, method of guidance, the number of teeth supporting the surgical guide, number of anchor pins, and presence or absence of a reinforcement structure. The effect of each factor that corrected each confounding was calculated using multivariate analysis.

Results

In this study, 188 implant bodies were set to target, and the errors measurement data of the implant position were as follows: average Angle, 2.5 ± 1.6° (95% CI 2.25–2.69); Base, 0.67 ± 0.37 mm (95% CI 0.62–0.72); and Apex, 0.92 ± 0.47 mm (95% CI 0.86–0.98). As the result of multivariate analysis, larger errors were present in the partially guided group than the fully guided group. The number of teeth supporting the surgical guide significantly influenced the error in placement position. The error caused by the number of anchor pins was significantly different for the Angle. Similarly, the presence of the reinforcement structure influenced the error significantly for the Angle.

Conclusions

It was suggested that the smaller errors could be present by performing guided surgery with full guidance and devising the design of the guide such as the number of teeth supporting the surgical guide, the setting of the anchor pin, and the reinforcement structure.

The accuracy of implant placement with computer-guided surgery in partially edentulous patients and possible influencing factors: A systematic review and meta-analysis

PURPOSE

To review the current clinical studies regarding the accuracy of implant computer-guided surgery in partially edentulous patients and investigate potential influencing factors.

STUDY SELECTION

Electronic searches on the PubMed and Cochrane Central Register of Controlled Trials databases, and subsequent manual searches were performed. Two reviewers selected the studies following our inclusion and exclusion criteria. Qualitative review and meta-analysis of the implant placement accuracy were performed to analyze potential influencing factors. Angular deviation, coronal deviation, apical deviation, and depth deviation were evaluated as the accuracy outcomes.

RESULTS

Eighteen studies were included in this systematic review, including six randomized controlled trials, nine prospective studies, and three retrospective clinical studies. A total of 1317 implants placed in 642 partially edentulous patients were reviewed. Eight studies were evaluated using meta-analysis. Fully guided surgery showed statistically higher accuracy in angular (P <0.001), coronal (P <0.001), and apical deviation (P <0.05) compared with pilot-drill guided surgery. A statistically significant difference (P <0.001) was also observed in coronal deviation between the bounded edentulous (BES) and distal extension spaces (DES). A significantly lower angular deviation (P <0.001) was found in implants placed using computer-aided design/computer-aided manufacturing (CAD/CAM) compared to the conventional surgical guides.

CONCLUSIONS

The edentulous space type, surgical guide manufacturing procedure, and guided surgery protocol can influence the accuracy of computer-guided surgery in partially edentulous patients. Higher accuracy was found when the implants were placed in BES, with CAD/CAM manufactured surgical guides, using a fully guided surgery protocol.

Validation of an Intra-Oral Scan Method Versus Cone Beam Computed Tomography Superimposition to Assess the Accuracy between Planned and Achieved Dental Implants: A Randomized In Vitro Study

Computer aided implantology is the safest way to perform dental implants. The research of high accuracy represents a daily effort. The validated method to assess the accuracy of placed dental implants is the superimposition of a pre-operative and a post-operative cone beam computed tomography (CBCT) with planned and placed implants. This procedure is accountable for a biologic cost for the patient. To investigate alternative procedure for accuracy assessment, fifteen resin casts were printed. For each model, six implants were digitally planned and then placed following three different approaches: (a) template guided free hand, (b) static computer aided implantology (SCAI), and (c) dynamic computer aided implantology (DCAI). The placement accuracy of each implant was performed via two methods: the CBCT comparison described above and a matching between implant positions recovered from the original surgical plan with those obtained with a post-operative intraoral scan (IOS). Statistically significant mean differences between guided groups (SCAI and DCAI) and the free hand group were found at all considered deviations, while no differences resulted between the SCAI and DCAI approaches. Moreover, no mean statistically significant differences were found between CBCT and IOS assessment, confirming the validity of this new method.

Expectation and reality of guided implant surgery protocol using computer-assisted static and dynamic navigation system at present scenario: Evidence-based literature review

In the field of modern dentistry, ideal three-dimensional positioning of dental implant with optimal prosthetic fit offers successful long-term outcomes. To achieve such accurate implant placement, presurgical evaluation of hard and soft tissue matters the most. Their efforts can be attained using various application programs such as digital imaging, implant planning software, laboratory- or computer-assisted surgical guides, and dynamic navigation approach. To overcome different opinions and choices regarding guided surgery, this article explains an evidence-based literature review to assess its various outcomes and allowing informed choices before using various guided surgical techniques based on its expectation and reality outcomes. This highlights a clinician's choice to guide his successful implant surgery without causing distress in the midway of treatment. An online search was done on PubMed/Medline database to bring in accuracy to the expertise. This review includes reference of publications from 2000 to 2019, which is related to promising outcomes using computer-assisted static or dynamic navigation system for the placement of implant. Out of these, 809 were related to the computer-guided implant placement. Relevant papers were chosen in accordance with the inclusion and exclusion criteria. This review article contemplates to reflect the fact that computer-guided approach is considered to offer more predictable, safer, and faster implant placement with the predetermined final prosthetic outfit. Thus, digital planning and placing of dental implants in the correct position keep escalating to a higher achievement levels than a classical freehand approach. Nevertheless, this guided surgical approach also holds some errors and risks, which must be identified and rectified.

Factors that Influence Direction Deviation in Freehand Implant Placement

PURPOSE

This retrospective study investigates the accuracy of freehand implant placement and whether the factors of presence of an adjacent tooth, implant quadrant, number of missing teeth, and location of the implant site influence direction and angulation deviations.

MATERIALS AND METHODS

According to specific inclusion and exclusion criteria, a total of 112 implants from 75 partially edentulous patients were recruited for this retrospective study. The implants were inserted using a freehand approach by one experienced clinician (right-handed). The full thickness flap was elevated to expose the alveolar bone in the implant surgery, and the implant crown consisted of an all-ceramic restoration retained by cement. The planned implant position was preoperatively determined using implant planning software. The postoperative implant position was determined by analyzing the alignment after optically scanning the dentition using a specifically designed registration model in Geomagic Studio software. The deviations between the planned and postoperative implant positions were then calculated. The outcomes included direction and angulation deviations between the planned and postoperative implant positions. All data were analyzed by ANOVA, Bonferroni correction, regression analysis, and one-sample t-tests conducted using SPSS.

RESULTS

The 3D deviations between planned and postoperative implant positions were 1.22 ± 0.63 mm at the entrance point, 1.91 ± 1.17 mm at the apical point, and 7.93 ± 5.56° in angulation. The presence of adjacent teeth influenced deviations in the mesiodistal (F = 4.338, p = 0.006) and buccolingual directions (F = 3.017, p = 0.033) at the entrance point and mesiodistal angulation (F = 7.979, p < 0.001). The quadrant influenced deviation in the buccolingual direction at the apical point (F = 6.093, p = 0.001) and buccolingual angulation (F = 6.457, p < 0.001). The number of missing teeth had no effect on deviations of direction and angulation of implants. The location of the implant site affected the deviation in the buccolingual direction at the entrance point (F = 3.096, p = 0.049) and the mesiodistal direction at the apical point (F = 3.724, p = 0.027).

CONCLUSION

The 3D accuracy of freehand-placed implants could be acceptable in clinical situations. The results showed that the presence of an adjacent tooth and the quadrant and the location of the implant site influenced the direction and angulation deviations of the implant position; however, the factor of number of missing teeth did not.

Methods Used to Assess the 3D Accuracy of Dental Implant Positions in Computer-Guided Implant Placement: A Review

The purpose of this review is to examine various assessment methods in order to compare the accuracy between the virtually planned and clinically achieved implant positions. In this review, comparison methods using pre- and post-operative computed topography (CT) data and digital impressions for definitive prosthesis will be described. The method for the displacement and strain for quantification of the error will also be explored. The difference between the planned and the actual implant placement position in guided implant surgery is expressed as an error. Assessing the accuracy of implant-guided surgery can play an important role as positive feedback in order to reduce errors. All of the assessment methods have their own inevitable errors and require careful interpretation in evaluation.

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.

Computerized implant-dentistry: Advances toward automation

Advancements in the field of implantology such as three-dimensional imaging, implant-planning software, computer-aided-design/computer-aided-manufacturing (CAD/CAM) technology, computer-guided, and navigated implant surgery have led to the computerization of implant-dentistry. This three-dimensional computer-generated implant-planning and surgery has not only enabled accurate preoperative evaluation of the anatomic limitations but has also facilitated preoperative planning of implant positions along with virtual implant placement and subsequently transferring the virtual treatment plans onto the surgical phase via static (guided) or dynamic (navigated) systems aided by CAD/CAM technology. Computerized-implant-dentistry being highly predictable and minimally invasive in nature has also allowed implant placement in patients with medical comorbidities (e.g. radiation therapy, blood dyscrasias), in patients with complex problems following a significant alteration of the bony anatomy as a result of benign or malignant pathology of the jaws or trauma and in patients with other physical and emotional problems. With significant achievements accomplished in the field of computerized implant-dentistry, attempts are now been made toward complete automation of implant-dentistry.

The diagnosis and conservative treatment of a complex type 3 dens invaginatus using cone beam computed tomography (CBCT) and 3D plastic models

AIM

To investigate the use of 3D plastic models, printed from cone beam computed tomography (CBCT) data, for accurate diagnosis and conservative treatment of a complex case of dens invaginatus.

SUMMARY

A chronic apical abscess with a draining sinus tract was diagnosed during the treatment planning stage of orthodontic therapy. Radiographic examination revealed a large radiolucent area associated with an invaginated right maxillary central incisor, which was found to contain a vital pulp. The affected tooth was strategic in the dental arch. Conventional periapical radiographs provided only partial information about the invagination and its relationship with the main root canal and with the periapical tissues. A limited-volume CBCT scan of the maxilla did not show evidence of communication between the infected invagination and the pulp in the main root canal, which could explain the pulp vitality. A novel method was adopted to allow for instrumentation, disinfection and filling of the invagination, without compromising the vitality of the pulp in the complex root canal system. The CBCT data were used to produce precise 3D plastic models of the tooth. These models facilitated the treatment planning process and the trial of treatment approaches. This approach allowed the vitality of the pulp to be maintained in the complex root canal space of the main root canal whilst enabling the healing of the periapical tissues.

KEY LEARNING POINTS

Even when extensive periapical pathosis is associated with a tooth with type III dens invaginatus, pulp sensibility tests should be performed. CBCT is a diagnostic tool that may allow for the management of such teeth with complex anatomy. 3D printed plastic models may be a valuable aid in the process of assessing and planning effective treatment modalities and practicing them ex vivo before actually performing the clinical procedure. Unconventional technological approaches may be required for detailed treatment planning of complex cases of dens invaginatus.