Dynamic navigation for zygomatic implant placement: A randomized clinical study comparing the flapless versus the conventional approach

Fully guided, flapless zygomatic implants for oncological rehabilitation-a technical note

Midface defects following head and neck cancer surgery present significant functional and aesthetic challenges. While free-tissue transfer is a favoured reconstructive approach, it may be contraindicated in the medically comorbid and failure may be catastrophic, resulting in significant morbidity. In such cases, zygomatic implant-retained prosthetic obturators provide an effective alternative. However, traditional zygomatic implant placement often requires the elevation of large full-thickness mucoperiosteal flaps, risking osteoradionecrosis in irradiated bone following postoperative radiotherapy. This technical note describes a novel method for fully guided, flapless zygomatic implant placement that was applied in a 74-year-old with a Brown Class IId maxillary defect following hemi-maxillectomy of a pT4aN0M0 right maxillary squamous cell carcinoma. Using virtual surgical planning, two zygomatic implants were placed utilizing 3D-printed tissue-borne drill guides based on the patient's obturator. These guides were designed with low tolerance flutes to minimize angular deviation and utilized hard and soft tissue undercuts to ensure stability. By using a flapless technique, trauma to the irradiated tissues was minimized, whilst achieving accurate zygomatic implant placement. This case highlights the importance of a multidisciplinary approach between the surgical, prosthetic, and engineering teams. Further studies are needed to validate the accuracy and predictability of this innovative approach.

The DN-PUBLIC framework for enhanced oral healthcare precision: a public health strategy for dynamic navigation integration-a narrative review

Oral health disparities remain a pressing global concern, especially in communities with limited access to specialized dental care. Implant dentistry, while transformative for tooth replacement, often relies on techniques that can be imprecise, operator-dependent, and prone to complications. Dynamic Navigation (DN), a real-time computer-assisted technology, offers a promising solution by enhancing accuracy, reducing errors, and supporting minimally invasive procedures. This narrative review explores how DN can improve clinical precision, reduce surgical complications, and make implantology more accessible and cost-effective. It introduces the DN-PUBLIC framework-a strategic, public health-focused approach for integrating DN into broader healthcare systems, with a strong alignment to the United Nations Sustainable Development Goals (SDGs).A comprehensive review of current literature was conducted, assessing DN's impact on surgical safety, recovery outcomes, cost-efficiency, and its growing role in dental education. The findings highlight that DN significantly improves implant placement accuracy and reduces risks such as nerve injury or misalignment. By allowing for flapless procedures and better soft tissue preservation, DN leads to quicker recovery and greater patient comfort. Beyond clinical outcomes, DN enables general practitioners to perform complex procedures more confidently, expanding access to quality care in underserved regions. Economic analyses also suggest reduced operative time, fewer complications, and lower healthcare costs. In conclusion, DN has the potential to transform public oral health by improving outcomes, training, and access. The DN-PUBLIC framework offers a clear roadmap to guide ethical, inclusive, and sustainable integration of DN technology in dental practice worldwide.

Autonomous dental robotic surgery for zygomatic implants: A two-stage technique

Zygomatic implants (ZIs) can be a treatment option for patients with severe atrophy in the maxilla, but deviation during ZI placement could lead to serious complications. Surgical guides and dynamic navigation have been used to improve the accuracy of ZI placement, but both techniques are subject to human error. A 2-stage technique is described that enabled an autonomous dental robot to overcome mouth-opening restrictions for ZI placement. The technique enables the complete digitalization of ZI placement, further improving the accuracy of the drilling process.

Influence of deviation tolerances on the positioning accuracy using computer aided dynamic navigation in endodontic surgery: a proof-of-concept

BACKGROUND

The operation accuracy of dynamic navigation is affected by deviation tolerance settings. This in vitro study was aimed to assess the influence of distance and angle deviation tolerances (DDT and ADT) on positioning accuracy in endodontic surgery using dynamic navigation.

MATERIALS AND METHODS

Standardized models were designed and three-dimensional (3D) printed. The drilling depth was 15 mm, where hemispherical cavities were reserved. According to the DDTs and ADTs, they were divided into five groups (n = 10), and the tolerances of distance/angle deviation were set at 0.3 mm/5°, 0.6 mm/3°, 0.6 mm/5°, 0.6 mm/7°, and 0.9 mm/5°. During navigation guidance, the operation was completed from the model surface to the cavity, the trajectory of the approach was fitted and compared with the design path, and the operational accuracy was calculated and analyzed using one-way ANOVA.

RESULTS

When the ADT was 5°, the positioning two-dimensional (2D) distance deviation of the DDT 0.3 mm group and the 0.6 mm group were 0.52 ± 0.14 mm and 0.50 ± 0.07 mm, respectively, smaller than 0.73 ± 0.17 mm of the 0.9 mm group (P <.01). The positioning 3D distance deviation of the 0.3 mm group and the 0.6 mm group were 0.55 ± 0.15 mm and 0.53 ± 0.07 mm, respectively, smaller than 0.74 ± 0.17 mm of the 0.9 mm group (P <.01). When the DDT was set as 0.6 mm, the positioning angle deviation of the ADT 3° group and the 5° group were 2.21 ± 0.42° and 2.60 ± 0.59°, respectively, smaller than 4.72 ± 0.64° of the 7° group (P <.01).

CONCLUSION

A 0.6 mm DDT and 5° ADT can reduce the positioning deviation of dynamic navigation and obtain better operability. The deviation tolerance of 0.6 mm/5° is suggested for application of dynamic navigation in endodontic surgery. It might improve the operation efficiency and ensure positioning accuracy.

Accuracy of freehand versus dynamic computer-assisted zygomatic implant placement: An in-vitro study

OBJECTIVE

To compare the accuracy of zygomatic implant placement using a dynamic computer-assisted implant surgery system (D-CAIS) versus the traditional freehand approach.

METHODS

An experimental in vitro study was conducted using 10 stereolithographic models randomized to two groups: D-CAIS (test group) and freehand placement (control group). A single zygomatic implant was placed on each side of the models. The accuracy of implant placement was assessed by superimposing the actual postoperative implant position, obtained via cone-beam computed tomography (CBCT), with the virtual preoperative surgical plan from the preoperative CBCT. Additionally, the operated side and surgery duration were recorded. Descriptive statistics and bivariate analyses were performed to evaluate the data.

RESULTS

The D-CAIS group demonstrated significantly greater accuracy across most outcome variables. Reductions in angular (MD = -5.33°; 95 %CI: -7.37 to -3.29; p < 0.001), coronal global (MD = -2.26 mm; 95 %CI: -2.97 to -1.55; p < 0.001), coronal horizontal 2D (MD = -1.96 mm; 95 %CI: -2.60 to -1.32; p < 0.001) and apical global deviations (MD = -3.37 mm; 95 %CI: -4.36 to -2.38; p < 0.001) were observed. Accuracy in the freehand group varied significantly between operated sides. However, the surgical procedures in the D-CAIS group were significantly longer (MD = 11.90 mins; 95 %CI: 9.37 to 14.44; p < 0.001).

CONCLUSIONS

D-CAIS navigation systems offer significantly greater accuracy in zygomatic implant placement compared to the traditional freehand technique. Additionally, D-CAIS systems may minimize discrepancies in accuracy between operated sides, though their use is associated with an increase in the duration of surgery.

CLINICAL SIGNIFICANCE

D-CAIS navigation systems improve the accuracy of zygomatic implant placement. However, an increase in the duration of surgery is to be expected.

Accuracy of freehand surgery, static and dynamic computer assisted surgery on zygomatic implant placement: A systematic review and meta-analyses

Real-time surgical navigation systems (dynamic computer-aided surgery, d-CAIS) and static guided surgery (static computer-aided surgery, s-CAIS) have been shown to enhance the accuracy of zygomatic implant (ZI) placement. The objective of this systematic review was to evaluate and compare the accuracy and risk of complications associated with d-CAIS and s-CAIS in ZI placement. A systematic review of published studies involving more than 4 patients was conducted to assess and compare the accuracy of d-CAIS and s-CAIS in zygomatic implant placement. Only one study included freehand ZI placement as a control. The primary outcomes measured were the accuracy of implant placement relative to preoperative planning, with a secondary focus on evaluating any potential complications. Out of 903 screened studies, 14 met the inclusion criteria. Freehand zygomatic implant placement was used as a control in only 1 study. The results revealed a mean apex deviation of 2.07 mm (95% CI: 2.01 to 2.13; I2 = 83.14%) for d-CAIS, 1.29 mm (95% CI: 1.15 to 1.43; I2 = 94.5%) for s-CAIS, and 4.98 mm (95% CI: 3.59 to 6.37; I2 = not assessable) for freehand placement. Reported complications included mucositis, reversible bilateral sinusitis, oroantral fistula, unspecified reversible postoperative complications, and fracture of the anterior wall of the zygoma. Both CAIS systems demonstrated high accuracy and safety in ZI placement, with a nearly 99% success rate at 6 months of follow-up. These findings suggest that both d-CAIS and s-CAIS are reliable methods for improving the precision and reducing the risks associated with ZI procedures.

ZygoPlanner: A three-stage graphics-based framework for optimal preoperative planning of zygomatic implant placement

Zygomatic implant surgery is an essential treatment option of oral rehabilitation for patients with severe maxillary defect, and preoperative planning is an important approach to enhance the surgical outcomes. However, the current planning still heavily relies on manual interventions, which is labor-intensive, experience-dependent, and poorly reproducible. Therefore, we propose ZygoPlanner, a pioneering efficient preoperative planning framework for zygomatic implantation, which may be the first solution that seamlessly involves the positioning of zygomatic bones, the generation of alternative paths, and the computation of optimal implantation paths. To efficiently achieve robust planning, we developed a graphics-based interpretable method for zygomatic bone positioning leveraging the shape prior knowledge. Meanwhile, a surface-faithful point cloud filling algorithm that works for concave geometries was proposed to populate dense points within the zygomatic bones, facilitating generation of alternative paths. Finally, we innovatively realized a graphical representation of the medical bone-to-implant contact to obtain the optimal results under multiple constraints. Clinical experiments confirmed the superiority of our framework across different scenarios. The source code is available at https://github.com/Haitao-Lee/auto_zygomatic_implantation.

Application of a semi-active robotic system for implant placement in atrophic posterior maxilla: A retrospective case series

OBJECTIVE

The study aimed to evaluate the accuracy and safety of a semi-active robotic system for implant placement in atrophic posterior maxilla.

METHODS

Patients underwent robot-assisted implant placement in atrophic posterior maxilla were identified and included. Cone-beam computed tomography (CBCT) was performed before surgery. The virtual implant position and drilling sequences were planned in the robotic planning system. Patients with positioning marker took an intraoral scan. The preoperative CBCT and the intraoral scan were superimposed in the robotic software. After registration, the implant bed was prepared utilizing the robotic arm with 1 mm safety margin below the maxillary sinus floor. The transcrestal sinus floor elevation (TSFE) was performed by the dentist, followed by the implant placement with the robotic arm. A postoperative CBCT was taken and superimposed with the preoperative one to calculate the accuracy of implant placement. Complications and adverse events were recorded. Deviations between the implant platform and apex levels were analyzed using the paired t-test. P < 0.05 was considered statistically significant.

RESULTS

Twenty-seven implants of 20 patients were included. No intraoperative and postoperative complications were reported. The global, lateral and vertical platform deviations were 0.73 ± 0.27 mm, 0.35 ± 0.23 mm and 0.35 ± 0.57 mm, respectively. The global, lateral and vertical apex deviations were 0.77 ± 0.23 mm, 0.41 ± 0.20 mm and 0.34 ± 0.57 mm, respectively. There were significant differences between the global, lateral and vertical deviations between the implant platform and apex levels (P < 0.05, respectively). The angular deviation was 1.58 ± 0.76°.

CONCLUSIONS

High accuracy and safety for implant placement in atrophic posterior maxilla could be achieved using a semi-active robotic system, with the TSFE procedure performed by the dentist.

CLINICAL SIGNIFICANCE

This study provides significant evidence to support the application of semi-active robotic systems for implant placement in atrophic posterior maxilla.

Accuracy of Zygomatic Implant Placement Using Task-Autonomous Robotic System or Dynamic Navigation: An In Vitro Study

OBJECTIVES

To evaluate and compare the accuracy of task-autonomous robot-assisted implant surgery (RAIS) and dynamic computer-assisted implant surgery (dCAIS) for zygomatic implant placement.

MATERIALS AND METHODS

Ten atrophic edentulous maxilla models requiring zygomatic implant (ZI) placement were randomly divided into the RAIS and dCAIS groups. Osteotomies and implant placement were performed under the guidance of a task-autonomous robotic system or dynamic navigation system. A total of 20 ZIs were analyzed. The angular, coronal, lateral coronal, coronal depth, apical, lateral apical, and apical depth deviations were measured and analyzed between the two groups. The primary outcome parameters were the angular deviations between the planned and the placed ZIs. Data was subjected to descriptive and comparative statistical analysis. The significance of inter-group differences for continuous variables was assessed with Student's two-sample t-tests, Welch two-sample t-tests, and Mann-Whitney U tests according to the distribution normality and variance homogeneity.

RESULTS

ZI placement deviations were compared between the RAIS and dCAIS groups, showing a mean angular deviation of 0.92 ± 0.40° versus 2.03 ± 0.53° (p < 0.001), a mean (±SD) coronal deviation of 0.48 ± 0.25 mm versus 1.29 ± 0.46 mm (p < 0.001), and a mean apical deviation of 0.88 ± 0.28 mm versus 1.96 ± 0.46 mm (p < 0.001).

CONCLUSIONS

For computer-guided ZI placement, task-autonomous RAIS was superior to dCAIS in terms of accuracy.

Dynamic navigation-guided robotic placement of zygomatic implants

OBJECTIVES

To assess the feasibility and accuracy of a new prototype robotic implant system for the placement of zygomatic implants in edentulous maxillary models.

METHODS

The study was carried out on eight plastic models. Cone beam computed tomographs were captured for each model to plan the positions of zygomatic implants. The hand-eye calibration technique was used to register the dynamic navigation system to the robotic spaces. A total of 16 zygomatic implants were placed, equally distributed between the anterior and the posterior parts of the zygoma. The placement of the implants (ZYGAN®, Southern Implants) was carried out using an active six-jointed robotic arm (UR3e, Universal Robots) guided by the dynamic navigation coordinate transformation matrix. The accuracy of the implant placement was assessed using EvaluNav and GeoMagicDesignX® software based on pre- and post-operative CBCT superimposition. Descriptive statistics for the implant deviations and Pearson's correlation analysis of these deviations to force feedback recorded by the robotic arm were conducted.

RESULTS

The 3D deviations at the entry and exit points were 1.80 ± 0.96 mm and 2.80 ± 0.95 mm, respectively. The angular deviation was 1.74 ± 0.92°. The overall registration time was 23.8 ± 7.0 min for each side of the model. Operative time excluding registration was 66.8 ± 8.8 min for each trajectory. The exit point and angular deviations of the implants were positively correlated with the drilling force perpendicular to the long axis of the handpiece and negatively correlated with the drilling force parallel to the long axis of the handpiece.

CONCLUSION

The errors of the dynamic navigation-guided robotic placement of zygomatic implants were within the clinically acceptable limits. Further refinements are required to facilitate the clinical application of the tested integrated robotic-dynamic navigation system.

CLINICAL SIGNIFICANCE

Robotic placement of zygomatic implants has the potential to produce a highly predictable outcome irrespective of the operator's surgical experience or fatigue. The presented study paves the way for clinical applications.

Feasibility, trueness and precision of intraoral scanners in digitizing maxillectomy defects with exposed zygomatic implants in situ: An in vitro 3D comparative study

OBJECTIVES

To in-vitro evaluate the feasibility and accuracy (trueness and precision) of various intraoral scanners (IOS) to digitize maxillectomy defect models with exposed zygomatic implants in situ.

MATERIAL AND METHODS

Six partially edentulous and edentulous maxillectomy defect models with 2 zygomatic implants each were obtained. References scans were obatined by using a laboratory scanner (inEos X5; Dentsply Sirona). Three IOS, Trios 3, Trios 4 (3Shape A/S), and Primescan (Dentsply Sirona) were used first to digitize the entire model including implants and then to only scan the exposed part of zygomatic implants. The feasibility was assessed by evaluating the intraoral scanner's ability to accurately capture the maxillectomy defects and zygomatic implants, compared to a reference standard. Trueness and precision were evaluated using software's global best-fit alignment (GOM Inspect, GOM GmbH). Multifactorial analysis of variance (ANOVA) was used to compare the mean 3D deviation according to different scanners, groups, and model types. The significance level used in the analyses was 5 % (α=0.05).

RESULTS

All scanners showed adequate feasibility to scan the entire maxillectomy defects and exposed implants regardless of the structural complexity. The results of trueness showed that Primescan has the smallest 3D deviations (0.0252 mm) followed by Trios 4 (0,0275 mm), and then Trios 3 (0.0318 mm) (p < 0.001). The results of precision showed that Primescan had the smallest 3D deviations (0.0026 mm) followed by Trios 3 (0,0080 mm), and then Trios 4 (0,0097 mm) (p < 0.001).

CONCLUSION

Intraoral scanners differ in feasibility, trueness and accuracy of all scans, with Primescan providing the best combination of feasibility, trueness and accuracy, followed by Trios 4 and Trios 3.

CLINICAL SIGNIFICANCE

Scanning maxillectomy defects with various exposed zygomatic implants can be feasible and accurate using intraoral scanners (Trios 3, Trios 4, and Primescan). The use of intraoral scanners for implant-prosthetic rehabilitation of maxillectomy defect can be a feasible alternative that can improve and simplify the workflow.

Combined static and dynamic computer-guided surgery for prosthetically driven zygomatic implant placement

OBJECTIVES

To propose and validate a minimally invasive combined static and dynamic computer assisted implant surgery (CAIS) workflow for zygomatic implant (ZI) placement.

METHODS

A combined approach leveraging static CAIS for initial positioning, complemented by dynamic CAIS for real-time control of the angle, depth and width was proposed. Fourteen consecutive patients (age: 60.3±9.8 years; 8 females) seeking ZI-supported restoration were enrolled. A single anatomically and prosthetically driven ZI on either the unilateral zygoma or bilateral zygomata was planned and placed using the proposed approach. The zygomatic anatomy-guided approach (ZAGA) type and the ZI length were recorded. The angular, coronal global, and apical global deviation between the planned and placed positions were measured by overlapping post- and pre-operative cone beam computer tomography. Comparisons were made between the left and right sides across the ZAGA type and ZI length. Statistical significance was set at P<0.05.

RESULTS

22 ZIs were placed using the combined approach and 13 immediate loading prostheses were delivered, with one patient restored 6 months after surgery. The angular deviations and coronal global deviations were 1.99±0.17° and 1.21±0.45 mm, respectively. The median apical global deviation was 1.67 mm (interquartile range [IQR]: 1.11-1.93 mm). No significant differences were found between the left and right sides across the ZAGA type or ZI length. All ZIs remained stable over a median follow-up of 14.5 months (IQR: 7-20 months).

CONCLUSIONS

The proposed combination of static and dynamic CAIS is safe, reliable, accurate, and robust for ZI placement.

CLINICAL SIGNIFICANCE

This pilot study proposed a minimally invasive ZI placement method that combined static and dynamic computer-guided surgery. The implant positioning accuracy achieved using this approach validated its safety, reliability, accuracy, and robustness. The combined approach may reduce the technique sensitivity of ZI placement, facilitating future rehabilitation of severely atrophic or defective maxillae.

Application of dynamic navigation technology in oral and maxillofacial surgery

OBJECTIVES

Dynamic navigation (DN) technology has ushered in a paradigm shift in dentistry, revolutionizing the precision of diverse procedures in oral and craniofacial surgery. This comprehensive review aims to review the manifold applications of DN, including implantology, endodontics, oral and dental surgeries, and other dental disciplines.

MATERIALS AND METHODS

A thorough search of the online databases PubMed and Google Scholar was conducted up to March 2024. Publications associated with DN in the field of oral and maxillofacial surgery were sourced.

RESULTS

Narrative literature review.

CONCLUSIONS

DN harnesses cone beam computerized tomography imaging, virtual design software, and motion tracking technology to construct a virtual model of the patient's oral cavity, affording real-time instrument tracking during procedures. Notably, in implantology, DN facilitates implant placement, enhances safety measures, and augments procedural efficiency. The application of DN in sinus lift procedures contributes to improved surgical outcomes and reduced complications. Within endodontics, DN guides root canal treatment (RCT), retreatment of failed RCT, and endodontic microsurgery, ensuring conservative access cavities and precise canal location. Beyond these, the versatility of DN extends to encompass maxillomandibular and orthognathic surgeries, tooth extraction, removal of foreign bodies, and facial reconstruction. However, it is crucial to acknowledge potential disadvantages and error-prone scenarios as DN technologies advance.

CLINICAL SIGNIFICANCE

DN technology empowers dentists with high accuracy, heightened safety protocols, and increased procedural efficiency, culminating in enhanced patient outcomes across various dental procedures. As DN technology further expands, its pivotal role will advance in the future of oral and maxillofacial surgery.

Comparison of robotic system and dynamic navigation for zygomatic implant placement: An in vitro study

OBJECTIVES

To compare the accuracy of robotic and dynamic navigation systems in assisting zygomatic implant (ZI) using an in vitro model experiment.

METHODS

Preoperative cone-beam computed tomography (CBCT) images of patients who underwent ZI treatment between 2011 and 2023 were collected from local databases. Corresponding three-dimensional resin models were printed and assigned to two groups: the robotic and dynamic navigation system groups. Following preoperative plans, ZIs were placed in the models with the assistance of either a robotic or dynamic navigation system. Deviations in the in vitro navigation surgery were measured and compared between the groups.

RESULTS

A total of 110 ZIs were placed in 56 models, with 55 ZIs in each group. No significant differences were observed in entry and angle deviations between the groups (p>0.05). However, the exit deviation in the robotic system group (2.39±1.24 mm) was larger than that in the dynamic navigation group (1.83±1.25 mm) (p<0.05). On the exit side, the Z-axis deviation in the robotic group (left: -0.28±1.43 mm, right: -0.21±1.30 mm) was smaller than that in the dynamic navigation group (left: 0.76±1.11 mm, right: 0.85±1.52 mm) (p<0.05), while no significant differences were found in X- and Y-axis deviations (p>0.05).

CONCLUSIONS

Compared with the dynamic navigation system, the robotic system can effectively prevent ZI overextension. However, its accuracy on the exit side is slightly lower than that of the dynamic navigation system.

CLINICAL SIGNIFICANCE

This preliminary in vitro study showed that the accuracy of the robotic system was slightly inferior to that of the dynamic navigation system in terms of exit deviation when used in ZI placement. Further clinical studies are required to confirm these findings.

Accuracy of dynamic computer-assisted implant surgery in fully edentulous patients: An in vitro study

OBJECTIVES

To compare miniscrew versus bone tracing registration methods on dental implant placement accuracy and time efficiency in edentulous jaws using a dynamic computer-assisted implant surgery (d-CAIS) system.

METHODS

Twelve fully edentulous maxillary models were allocated into two groups: miniscrew tracing (MST) group, where registration was performed by tracing four miniscrews; and bone tracing (BT) group, where registration was conducted by tracing maxillary bone fiducial landmarks. Six implants were placed on each model using the X-Guide® d-CAIS system. Pre- and postoperative cone-beam computed tomography (CBCT) scans were superimposed to evaluate implant placement accuracy. The time required for registration and the overall surgery time were also recorded.

RESULTS

Thirty-six implants were placed in each group. The MST group showed significantly lower mean angulation deviations (mean difference (MD): -3.33°; 95 % confidence interval (CI): -6.56 to -0.09); p = 0.044), 3D platform deviations (MD: -1.01 mm; 95 % CI: -1.74 to -0.29; p = 0.006), 2D platform deviations (MD: -0.97 mm; 95 % CI: -1.71 to -0.23; p = 0.010), and 3D apex deviations (MD: -1.18 mm; 95 % CI: -1.92 to -0.44; p = 0.002) versus the BT group. The overall surgery time was similar for both groups (MD: 6.10 min.; 95 % CI: -0.31 to 12.51; p = 0.06), though bone tracing required significantly more time compared with miniscrew registration (MD: 4.79 min.; 95 % CI: 2.96 to 6.62; p < 0.05).

CONCLUSIONS

Registration with MST increases the accuracy of implant placement with a d-CAIS system in edentulous jaws compared with the BT method, and slightly reduces the overall surgery time.

CLINICAL SIGNIFICANCE

Miniscrew tracing registration improves implant placement accuracy in comparison with bone tracing registration.

A fully digital planning protocol for dynamic computer-assisted zygomatic implant surgery based on virtual surgery simulation: A dental technique

Dynamic navigation-guided zygomatic implant (ZI) surgery has been a preferred option for achieving optimal prosthetic-driven implant placement. However, during the actual surgical procedure, surgical execution may still be hindered by environmental factors such as mouth opening. A fully digital planning protocol is described that integrated the patient's maxillofacial soft tissue information and virtual surgical handpiece with the drills on the implant planning path to ensure the precise, time-saving, and smooth implementation of dynamic navigation-guided ZI surgery.

Accuracy of dental implant placement using different dynamic navigation and robotic systems: an in vitro study

Computer-aided implant surgery has undergone continuous development in recent years. In this study, active and passive systems of dynamic navigation were divided into active dynamic navigation system group and passive dynamic navigation system group (ADG and PDG), respectively. Active, passive and semi-active implant robots were divided into active robot group, passive robot group and semi-active robot group (ARG, PRG and SRG), respectively. Each group placed two implants (FDI tooth positions 31 and 36) in a model 12 times. The accuracy of 216 implants in 108 models were analysed. The coronal deviations of ADG, PDG, ARG, PRG and SRG were 0.85 ± 0.17 mm, 1.05 ± 0.42 mm, 0.29 ± 0.15 mm, 0.40 ± 0.16 mm and 0.33 ± 0.14 mm, respectively. The apical deviations of the five groups were 1.11 ± 0.23 mm, 1.07 ± 0.38 mm, 0.29 ± 0.15 mm, 0.50 ± 0.19 mm and 0.36 ± 0.16 mm, respectively. The axial deviations of the five groups were 1.78 ± 0.73°, 1.99 ± 1.20°, 0.61 ± 0.25°, 1.04 ± 0.37° and 0.42 ± 0.18°, respectively. The coronal, apical and axial deviations of ADG were higher than those of ARG, PRG and SRG (all P < 0.001). Similarly, the coronal, apical and axial deviations of PDG were higher than those of ARG, PRG, and SRG (all P < 0.001). Dynamic and robotic computer-aided implant surgery may show good implant accuracy in vitro. However, the accuracy and stability of implant robots are higher than those of dynamic navigation systems.

The precision of drill calibration for dynamic navigation

OBJECTIVES

To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy.

METHODS

A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants' entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investigated. The outcome measures for reproducibility were expressed in terms of variability range, average and maximum deviations from the mean distance.

RESULTS

A satisfactory inter-rater reproducibility was noted. The precision of the calibration of the tip position in terms of variability range was between 0.3 and 3.7 mm. We noted a tendency towards a higher precision of the calibration process with longer drills. More calibration errors were observed when calibrating long zygomatic implants with non-locking adapters than with pointed drills. Flexible long-pointed drills had low calibration precision that was comparable to the non-flexible short-pointed drills.

CONCLUSION

The clinicians should be aware of the calibration error associated with the dynamic navigation placement of dental and zygomatic implants. This should be taken in consideration especially for long implants, short drills, and long drills that have some degree of flexibility.

CLINICAL SIGNIFICANCE

Dynamic navigation procedures are associated with an inherent drill calibration error. The manual stability during the calibration process is crucial in minimising this error. In addition, the clinician must never ignore the prescribed accuracy checking procedures after each calibration process.

Evaluation of the Long-Term Success and Patient-Related Outcomes of Zygomatic Implants in Atrophic Maxillary Ridges

Introduction Zygomatic implants (ZIs) have emerged as a promising option for rehabilitating completely edentulous patients with severe maxillary atrophy. These implants anchor into the zygomatic bone, bypassing the need for extensive grafting procedures. Success rates in dental and craniofacial implant surgeries can be influenced by several surgical factors, including suture techniques, flap design, and treatment planning. The research aimed to present the clinical outcomes and complications in individuals with severely resorbed maxillae who underwent prosthodontic rehabilitation using the Quad Zygoma Protocol (QZP) and the Anatomy-Guided Approach (AGA), focusing on long-term assessment. Material and methods Data for this retrospective study were extracted from the institution's patient database, involving a meticulous review of patient records. This comprehensive examination encompassed demographic data, preoperative assessments, details of surgical procedures, postoperative complications, and subsequent follow-up evaluations. Patients with severe maxillary bone deficiencies resulting in complete edentulism, due to inadequate bone quality and quantity in both anterior and posterior regions, were selected for inclusion. Exclusion criteria were applied to individuals with incomplete records or insufficient follow-up data, as well as those who underwent alternative treatment modalities or presented with comorbidities potentially impacting implant outcomes. The selected patients underwent treatment utilizing the QZP, with each participant subjected to a minimum three-year follow-up period. The implant survival rate, prosthetic success, complications, and Oral Health-Related Quality of Life using the OHIP-14 questionnaire were assessed. Results At the end of the follow-up period involving 12 patients (eight men, four women) with 43 ZIs - 37 from Neodent, four from Nobel Biocare, and two from Norris - with a mean duration of 4.3 years (range: 1.2-5.4), the overall success rate stood at 99.08%, with only 1 out of 42 implants failing. All patients received immediate loading with an acrylic prosthesis, proving effective in 98.2% of cases. The most common issues observed were localized soft tissue inflammation (35.7%) and sinus inflammation (12.5%), occurring after mean follow-up periods of 1.2 and 3.5 years, respectively. In 12 patients, the mean score of the OHIP-14 questionnaire was 1.6 ± 2.6, with a follow-up period of 5 ± 0.6 years. Conclusion The QZP has consistently demonstrated excellent long-term success in restoring severely reduced maxillary structures. An immediate loading approach could aid in stabilizing ZIs through cross-arch support.

Accuracy of implant placement using a mixed reality-based dynamic navigation system versus static computer-assisted and freehand surgery: An in Vitro study

PURPOSE

This in vitro study aimed to compare the accuracy of dental implant placement in partially edentulous maxillary models using a mixed reality-based dynamic navigation (MR-DN) system to conventional static computer-assisted implant surgery (s-CAIS) and a freehand (FH) method.

METHODS

Forty-five partially edentulous models (with teeth missing in positions #15, #16 and #25) were assigned to three groups (15 per group). The same experienced operator performed the model surgeries using an MR-DN system (group 1), s-CAIS (group 2) and FH (group 3). In total, 135 dental implants were placed (45 per group). The primary outcomes were the linear coronal deviation (entry error; En), apical deviation (apex error; Ap), XY and Z deviations, and angular deviation (An) between the planned and actual (post-surgery) position of the implants in the models. These deviations were computed as the distances between the stereolithographic (STL) files for the planned implants and placed implants captured with an intraoral scanner.

RESULTS

Across the three implant sites, the MR-DN system was significantly more accurate than the FH method (in XY, Z, En, Ap and An) and s-CAIS (in Z, Ap and An), respectively. However, S-CAIS was more accurate than MR-DN in XY, and no difference was found between MR-DN and s-CAIS in En.

CONCLUSIONS

Within the limits of this study (in vitro design, only partially edentulous models), implant placement accuracy with MR-DN was superior to that of FH and similar to that of s-CAIS.

STATEMENT OF CLINICAL RELEVANCE

In vitro, MR-DN showed greater accuracy in implant positioning than FH, and similar accuracy to s-CAIS: it could, therefore, represent a new option for the surgeon. However, clinical studies are needed to determine the feasibility of MR-DN.

Long-term survival and complications of Quad Zygoma Protocol with Anatomy-Guided Approach in severely atrophic maxilla: A retrospective follow-up analysis of up to 17 years

INTRODUCTION

The objective of the study was to provide long-term clinical outcomes and complications in the severely atrophic edentulous maxillae treated by means of the quad zygoma protocol (QZP) using the Anatomy-Guided Approach (AGA).

METHODS

This was a retrospective cohort study of all consecutive patients with severely atrophic edentulous maxilla and insufficient bone height and width in the anterior and posterior regions bilaterally, who underwent rehabilitation with the QZP between May 2006 and December 2021. All patients were followed for at least 1 year. All zygomatic implants (ZIs) were placed by the same surgeon. The primary endpoint of the study was the implant survival rate. Secondary endpoints were implant success rate, prosthesis success rate, complications, and Oral Health-Related Quality of Life using the OHIP-14 questionnaire.

RESULTS

A total of 56 patients (men 16, women 40) with 224 ZIs (Nobel Biocare, n = 204; Straumann, n = 16; Southern Implant, n = 4) placement were included with a mean follow-up period 8.8 ± 3.9 years (range, 1.2-17.0). The survival (success) rate was 97.7%. Five ZIs in four patients failed. The mean time between implant placement and failure was 8.6 years (range, 0.5-13.3). All patients received immediate loading with acrylic prosthesis. The successful rates for the definitive prosthesis were 98.2%. Forty-two patients received posterior cantilever for rehabilitation of fixed definitive prosthesis. Local orofacial inflammation (35.7%) and Sinusitis (12.5%) were the most common complications, occurring at a mean follow-up of 10.0 (range, 4.2-14.9) and 10.3 (range, 4.3-16.2) years, respectively. In 48 patients, the mean score of the OHIP-14 questionnaire was 1.7 ± 2.6 with the follow-up period of 9.0 ± 4.1 years.

CONCLUSIONS

The rehabilitation of severely atrophic edentulous maxilla using the QZP has shown a predictable and high survival rate in the long term. The implementation of an immediate loading protocol offers potential benefits in stabilizing ZIs with cross-arch stabilization. Moreover, the use of a posterior cantilever in reconstruction can effectively establish functional occlusion through well-distributed ZIs, eliminating the need for additional implant placement.

Feasibility and accuracy of a task-autonomous robot for zygomatic implant placement

STATEMENT OF PROBLEM

Zygomatic implants (ZIs) should be placed accurately as planned preoperatively to minimize complications and maximize the use of the remaining bone. Current digital techniques such as static guides and dynamic navigation are affected by human error; therefore, new techniques are required to improve the accuracy of ZI placement.

PURPOSE

The purpose of this clinical study was to assess the feasibility and accuracy of a task-autonomous robot for ZI placement.

MATERIAL AND METHODS

Patients indicated for ZI placement were enrolled, and an appropriate surgical positioning piece was selected based on the presence of natural teeth in the maxilla. Preoperative cone beam computed tomography (CBCT) scanning was performed with the surgical positioning piece, and virtual implant design and socket preparation procedures were initiated. Implant socket preparation and placement were automatically performed by the robot according to the preoperative plan under the supervision of the surgeon. Postoperative CBCT scanning was performed to evaluate deviations between the virtual and actual implants. All quantitative data were expressed as standardized descriptive statistics (mean, standard deviation, minimum, maximum, and 95% confidence interval [CI]). The Shapiro-Wilk test was used to assess the normal distribution of all variables (α=.05).

RESULTS

Six participants were enrolled, and 8 ZIs were inserted. No intraoperative or postoperative complications were observed. Robotic ZI placement showed a global coronal deviation of 0.97 mm (95% CI: 0.55 to 1.39 mm), a global apical deviation of 1.27 mm (95% CI: 0.71 to 1.83 mm), and an angular deviation of 1.48 degrees (95% CI: 0.97 to 2.00 degrees).

CONCLUSIONS

Task-autonomous robots can be used for ZI placement with satisfactory accuracy. Robotic ZI surgery can be an alternative to static guidance and dynamic navigation to improve the accuracy of implant placement.

Clinical efficacy of computer-assisted zygomatic implant surgery: A systematic scoping review

STATEMENT OF PROBLEM

Digital technology can improve the success of zygomatic implant (ZI) surgery. However, the reliability and efficacy of computer-assisted zygomatic implant surgery (CAZIS) need further analysis.

PURPOSE

The purpose of this scoping review was to provide an overview of the placement accuracy, implant survival, and complications of CAZIS.

MATERIAL AND METHODS

A systematic search of English and Mandarin Chinese publications up to May 2023 was conducted in PubMed, Web of Science, Embase, and Wanfang database. The nonpeer-reviewed literature was searched in the trial register (clinicaltrials.gov). Clinical studies and cadaver studies on CAZIS were included. After data extraction and collection, the findings were critically reviewed, analyzed, interpreted, and discussed.

RESULTS

Forty-one studies met the inclusion criteria. After excluding publications with duplicate data, retaining the most recent, 28 articles were included in this scoping review. Of these, 18 were on static computer-assisted zygomatic implant surgery (sCAZIS), 8 on dynamic computer-assisted zygomatic implant surgery (dCAZIS), and 2 on robot-assisted zygomatic implant surgery (rAZIS). Excluding the outliers, the mean deviations of ZIs in the sCAZIS group (with 8 articles reporting implant placement accuracy, 183 ZIs involved) were: 1.15 ±1.37 mm (coronal deviation), 2.29 ±1.95 mm (apical deviation), and 3.32 ±3.36 degrees (angular deviation). The mean deviations of dCAZIS (3 articles, 251 ZIs) were: 1.60 ±0.74 mm (coronal), 2.27 ±1.05 mm (apical), and 2.89 ±1.69 degrees (angular). The mean deviations of rAZIS (2 articles, 5 ZIs) were: 0.82 ±0.21 mm (coronal), 1.25 ±0.52 mm (apical), and 1.46 ±0.35 degrees (angular). Among the CAZIS reported in the literature, the implant survival rate was high (96.3% for sCAZIS, 98.2% for dCAZIS, and 100% for rAZIS, specified in 14 of 21 clinical studies). The incidence of complications was low, but, because of the few relevant studies (4/21 specified), valid conclusions regarding complications could not be drawn.

CONCLUSIONS

CAZIS has demonstrated clinical efficacy with high implant survival rates and placement accuracy. Of the 3 guided approaches, rAZIS showed the smallest 3-dimensional deviation.

The Accuracy of Zygomatic Implant Placement Assisted by Dynamic Computer-Aided Surgery: A Systematic Review and Meta-Analysis

PURPOSE

The present systematic review aimed to investigate the accuracy of zygomatic implant (ZI) placement using dynamic computer-aided surgery (d-CAIS), static computer-aided surgery (s-CAIS), and a free-hand approach in patients with severe atrophic edentulous maxilla and/or deficient maxilla.

METHODS

Electronic and manual literature searches until May 2023 were performed in the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases. Clinical trials and cadaver studies were selected. The primary outcome was planned/placed deviation. Secondary outcomes were to evaluate the survival of ZI and surgical complications. Random-effects meta-analyses were conducted and meta-regression was utilized to compare fiducial registration amounts for d-CAIS and the different designs of s-CAIS.

RESULTS

A total of 14 studies with 511 ZIs were included (Nobel Biocare: 274, Southern Implant: 42, SIN Implant: 16, non-mentioned: 179). The pooled mean ZI deviations from the d-CAIS group were 1.81 mm (95% CI: 1.34-2.29) at the entry point and 2.95 mm (95% CI: 1.66-4.24) at the apex point, and angular deviations were 3.49 degrees (95% CI: 2.04-4.93). The pooled mean ZI deviations from the s-CAIS group were 1.19 mm (95% CI: 0.83-1.54) at the entry point and 1.80 mm (95% CI: 1.10-2.50) at the apex point, and angular deviations were 2.15 degrees (95% CI: 1.43-2.88). The pooled mean ZI deviations from the free-hand group were 2.04 mm (95% CI: 1.69-2.39) at the entry point and 3.23 mm (95% CI: 2.34-4.12) at the apex point, and angular deviations were 4.92 degrees (95% CI: 3.86-5.98). There was strong evidence of differences in the average entry, apex, and angular deviation between the navigation, surgical guide, and free-hand groups (p < 0.01). A significant inverse correlation was observed between the number of fiducial screws and the planned/placed deviation regarding entry, apex, and angular measurements.

CONCLUSION

Using d-CAIS and modified s-CAIS for ZI surgery has shown clinically acceptable outcomes regarding average entry, apex, and angular deviations. The maximal deviation values were predominantly observed in the conventional s-CAIS. Surgeons should be mindful of potential deviations and complications regardless of the decision making in different guide approaches.

Cost-effectiveness of the Flapless Insertion of Zygomatic Implants Using Dynamic Navigation - A Retrospective Study

Introduction

Zygomatic implants are an effective solution for rehabilitation of edentulous atrophic maxillae. However, the conventional technique of zygomatic implant placement is invasive, requires a longer healing period and is economically cumbersome. Therefore, the flapless technique of insertion of zygomatic implants using dynamic navigation system has been introduced. This study aims to compare the cost-effectiveness of flapless insertion of zygomatic implants using dynamic navigation to the conventional flap technique.

Materials and Methods

The study participants were divided into two groups: Group A (n = 20) included patients treated by flapless insertion of zygomatic implants using dynamic navigation and Group B (n = 20) included patients treated with zygomatic implants using the flap technique. An analysis of the effectiveness of the implants was done using the concept of quality-adjusted prosthesis years, and an analysis of the costs was done by evaluating the treatment costs at each step. The data were collected, and analysis was done using IBM SPSS software. The Kruskal-Wallis rank-sum test was employed to analyse variations in costs and effects between the two groups.

Results

The study showed that the distribution of costs varies across both the categories of the procedure. Group B shows lesser cost-effectiveness as compared to Group A.

Conclusion

The technique of flapless insertion of zygomatic implants is cost-effective. However, further studies considering factors such as time and cost of productivity evaluating the cost-effectiveness should be conducted.

Accuracy of computer-aided static and dynamic navigation systems in the placement of zygomatic dental implants

BACKGROUND

Zygomatic implants are widely used in the rehabilitation of severely atrophic maxillae, but implant placement is not without risks, and it can potentially cause damage to related anatomical structures. The aim of this study was to perform a comparative analysis of the accuracy of static navigation systems in placing zygomatic dental implants in comparison to dynamic navigation systems.

METHODS

Sixty zygomatic dental implants were randomly allocated to one of three study groups, categorized by which implant placement strategy was used: A: computer-aided static navigation system (n = 20) (GI); B: computer-aided dynamic navigation system (n = 20) (NI); or C: free-hand technique (n = 20) (FHI). For the computer-aided study groups, a preoperative cone-beam computed tomography (CBCT) scan of the existing situation was performed in order to plan the approach to be used during surgery. Four zygomatic dental implants were inserted in each of fifteen polyurethane stereolithographic models (n = 15), with a postoperative CBCT scan taken after the intervention. The pre- and postoperative CBCT scans were then uploaded to a software program used in dental implantology to analyze the angular deviations, apical end point, and coronal entry point. Student's t-test was used to analyze the results.

RESULTS

The results found statistically significant differences in apical end-point deviations between the FHI and NI (p = 0.0053) and FHI and GI (p = 0.0004) groups. There were also statistically significant differences between the angular deviations of the FHI and GI groups (p = 0.0043).

CONCLUSIONS

The manual free-hand technique may enable more accurate placement of zygomatic dental implants than computer-assisted surgical techniques due to the different learning curves required for each zygomatic dental implant placement techniques.