Automatic robot-world calibration in an optical-navigated surgical robot system and its application for oral implant placement

Current Status and Future Perspectives of Robot-Assisted Dental Implant Surgery

Dental implant surgery is now a well versed approach for tooth replacement, addressing various limitations of fixed bridges and removable dentures, thereby reinstating both the form and function of missing teeth. However, it is technically sensitive and highly dependent on the clinical experience and the expertise of the dentist. With breakthrough progress in robot-assisted surgery for a variety of systemic diseases, robot-assisted dental implant surgery has emerged as a new way to potentially enhance the efficacy of dental implant procedures. Widely researched by dental researchers, it is progressively revealing advantages in the treatment of dentition defects or edentulism. This article summarizes the current research status of robot-assisted dental implant surgery and provides a perspective grounded in the ongoing research landscape.

Accuracy and safety of implant placement with a novel semi-autonomous robotic-assisted surgical system: A translational research study

STATEMENT OF PROBLEM

Translational studies evaluating the feasibility, accuracy, and safety of semi-autonomous implant robots, from model test to animal experiment and clinical trial, are currently lacking.

PURPOSE

The purpose of this study was to evaluate the accuracy and safety of a novel semi-autonomous robotic-assisted surgical system (sa-RASS) in implant placement.

MATERIAL AND METHODS

A translational study was conducted to assess the application of the sa-RASS in a model test, an animal experiment, and a clinical controlled trial. The study included 45 resin models in the model test, 7 male beagle dogs in the animal experiment, and 60 participants who were recruited and randomly assigned to a freehand or a sa-RASS group in the clinical trial. The accuracy, surgical morbidity, complications, operator ratings of instrument safety, and satisfaction were recorded. Cone beam computed tomography data were used to evaluate deviations between planned and placed implants. The data on deviations were analyzed using the Mann-Whitney U test. A linear regression model was established to analyze the variations in the deviations (α=.05).

RESULTS

The mean ±standard deviation of the platform, apex, and angulation deviations were 0.98 ±0.53 mm, 1.10 ±0.52 mm, and 1.45 ±0.60 degrees in the model test and 0.58 ±0.19, 0.59 ±0.22 mm, and 1.88 ±0.71 degrees in the animal experiment. In the clinical controlled study, the platform, apex, and angular deviations of the sa-RASS group and freehand group were 0.93 ±0.50 mm versus 1.45 ±0.86 mm (P<.01), 1.07 ±0.63 mm versus 2.05 ±1.16 mm (P<.001), and 3.10 ±1.68 degrees versus 7.94 ±3.55 degrees (P<.001). No complications, such as early implant failure, intraoperative hemorrhage, injuries to adjacent structures, or implant displacement beyond the apical anatomic limit, were observed in the sa-RASS group. The results of the linear regression model showed that age, sex, bone density, implant position, implant diameter, and length did not significantly influence the accuracy of implantation at the apex or the angulation (P>.05).

CONCLUSIONS

The sa-RASS was found to be more accurate than freehand placement, with high operational safety and low surgical morbidity.

Accuracy of robotic computer-assisted implant surgery in clinical studies: a systematic review and meta-analysis

OBJECTIVES

To analyze the accuracy of the robotic system in clinical studies and assess potential factors that might affect the accuracy of robotic implant placement.

MATERIALS AND METHODS

PubMed, Embase, and Cochrane Central Register of Controlled Trials were used to search for studies published from August 2014 till October 2024. Studies on robotic computer-assisted implant surgery (R-CAIS) were identified. Furthermore, manual searches were performed for selected journals. Only clinical studies were included. Subgroup analysis was performed based on robot autonomy, different dentitions, and the working principle of the camera.

RESULTS

Sixteen studies met the inclusion criteria, evaluating 908 implants. The meta-analysis of accuracy showed that the average global platform deviation, global apex deviation, and angular deviation were 0.69 mm (95% CI: 0.61‒0.77, I2 = 94%), 0.72 mm (95% CI: 0.64‒0.79, I2 = 93%), and 1.62° (95% CI: 1.34°‒1.89°, I2 = 96%), respectively. In subgroup analysis, Meta-generic inverse variance analysis observed statistically significant differences in global platform deviation and apex deviation between robots using infrared and mechanical tracking (p < 0.01), as well as between those using visible light and mechanical tracking (p < 0.01). No significant differences were observed between autonomous and semi-active systems and different dentitions.

CONCLUSION

The R-CAIS technology demonstrated a high level of accuracy. However, further large-scale, multi-center, randomized, controlled clinical trials are necessary to compare robotic implant placement with other techniques, and the additional factors influencing robotic implant placement must be explored.

Accuracy of bi-coordinate and multi-coordinate handpiece calibration methods for robot-assisted implant placement

STATEMENT OF PROBLEM

To ensure accurate robot-assisted surgery, it is essential to identify the handpiece position at the end effector of the robotic arm. Clinically, the relationship between the optical tracking device and the handpiece has been typically confirmed by using a calibration plate at the end effector of the robotic arm. However, the accuracy of the handpiece calibration methods for robot-assisted implant placement remains unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the accuracy of bi-coordinate and multi-coordinate handpiece calibration methods, as well as the multi-coordinate handpiece plate under partial obstruction, in the context of robot-assisted implant placement.

MATERIAL AND METHODS

In total, 120 implants were divided into 6 groups based on the calibration plate used in the study: bi-coordinate handpiece calibration plate for the maxilla (Bmx), bi-coordinate handpiece calibration plate for the mandible (Bmn), multi-coordinate handpiece calibration plate for the maxilla (Mmx), multi-coordinate handpiece calibration plate for the mandible (Mmn), partially obscured multi-coordinate handpiece calibration plate for the mandible with the primary coordinate unblocked and the auxiliary coordinate covered (MmnPrim), and partially obscured multi-coordinate handpiece calibration plate for the mandible with the auxiliary coordinate unblocked and the primary coordinate covered (MmnAux). Calibration of the robotic arm was conducted separately for each group. Then the robot autonomously performed osteotomies and implant placements at the first and second premolars according to the preoperative plan. Following surgery, the robotic software program calculated the deviation values between the planned and actual implant positions. Differences between the test groups were analyzed using 1-way analysis of variance (ANOVA) and the Bonferroni post hoc test (α=.05).

RESULTS

The ranges of angular deviation and 3-dimensional deviations at the implant platform and apex across the 6 groups were 0.30 degrees to 0.48 degrees, 0.31 to 0.36 mm, and 0.31 to 0.38 mm, respectively. No statistically significant differences were found among the groups (P>.05).

CONCLUSIONS

Both the bi-coordinate and multi-coordinate handpiece calibration methods demonstrated acceptable accuracy for robot-assisted implant placement. The multi-coordinate calibration plate provides a feasible method for robot calibration in scenarios where the mandible is partially obstructed.

Accuracy of robot-assisted implant surgery versus freehand placement: a retrospective clinical study

PURPOSE

This study evaluated the accuracy of implant placement using a robotic system (Remebot) compared to freehand surgery and explored factors influencing accuracy.

METHODS

This retrospective study included 95 implants placed in 65 patients, divided into robot-assisted (50 implants) and freehand (45 implants) groups. Platform, apical, and angular deviations were measured by superimposing preoperative plans and the postoperative CBCT images. Mean deviations between groups were compared, and regression analysis assessed the impact of implant dimensions and positioning on accuracy.

RESULTS

The robot-assisted group exhibited significantly lower mean deviations in platform (0.44 ± 0.17 mm), apical (0.46 ± 0.17 mm), and angular deviations (0.85 ± 0.47°) compared to the freehand group (1.38 ± 0.77 mm, 1.77 ± 0.82 mm, and 6.63 ± 3.90°, respectively; p < 0.001). Regression analysis indicated no significant impact of implant location, jaw type, or implant dimensions on the robotic system's accuracy, unlike the freehand placement where these factors influenced deviations.

CONCLUSIONS

Robot-assisted implant surgery significantly enhances accuracy and clinical safety compared to freehand techniques. Despite limitations, robotic surgery presents a promising advancement in implant dentistry by reducing human error.

Clinical and in vitro application of robotic computer-assisted implant surgery: a scoping review

In recent years, the emergence and application of robotic computer-assisted implant surgery (r-CAIS) has resulted in a revolutionary shift in conventional implant diagnosis and treatment. This scoping review was performed to verify the null hypothesis that r-CAIS has a relatively high accuracy of within 1 mm, with relatively few complications and a short operative time. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). From the 3355 publications identified in the PubMed, Scopus, Web of Science, and Google Scholar databases, 28 were finally included after a comprehensive review and analysis. The null hypothesis is partly accepted, as r-CAIS has a relatively high accuracy (coronal and apical deviation within 1 mm), and no significant adverse events or complications have been reported to date, although additional confirmatory studies are needed. However, there is insufficient evidence for a shorter surgical time, and further clinical research on this topic is required.

Prediction of primary stability via the force feedback of an autonomous dental implant robot

STATEMENT OF PROBLEM

While the high osteotomy and implant placement accuracy via robotic implant surgery has been verified, whether the force feedback in the osteotomy process can be used to determine appropriate primary implant stability remains unknown.

PURPOSE

The purpose of this in vitro study was to explore the relationship between the force feedback and the primary stability of implants placed by using an autonomous dental implant robot.

MATERIAL AND METHODS

Five groups (n=7) of wooden and polyurethane foam blocks were used to execute an implant surgery by using an autonomous implant robot. Tapered bone-level titanium dental implant replicas were placed in the blocks. The Young modulus, the maximal vertical and lateral drilling resistances, the position accuracy, and the insertion torque of implants were recorded. Simple linear regression, principal component analysis, and multiple linear regression were used. The osteotomy strategy for the implant site was adjusted according to the maximal vertical resistance of the pilot drill to achieve appropriate insertion torque. The correlation, Gompertz growth curve fitting of the insertion torque, and Young modulus were determined. The effect of the drilling resistances on the insertion torque was analyzed using 2-way ANOVA, simple linear regression, and the principal component analysis.

RESULTS

The vertical resistance of the Ø2.2-mm pilot drill, the Ø3.5-mm twist drill, and the Ø4.1-mm profile drill had a strong simple linear correlation with the insertion torque of the implants, and the lateral resistance had a moderate linear correlation with the insertion torque. The contributions of these 6 variables to the implant torque, among which the vertical resistance of the twist drill and the pilot drill ranked first and second, were comparable. Adjustments to the strategy of site preparation according to the vertical resistance of the pilot drill achieved appropriate insertion torque (P<.001).

CONCLUSIONS

The force feedback of the autonomous dental implant robot was significantly correlated with the insertion torque of implants, which may fit an interpretable mathematical model, allowing dental implants to be placed with predictable primary stability.

Accuracy of robotic-assisted surgery for immediate implant placement in posterior teeth: a retrospective case series

BACKGROUND

Robotic computer-assisted implant surgery (r-CAIS) is a revolutionary innovation in oral implantation; however, the clinical feasibility of r-CAIS for immediate implant placement (IIP) in posterior teeth has not been verified. Thus, this study aimed to evaluate the accuracy of r-CAIS for IIP in posterior tooth regions.

METHODS

Patients with posterior teeth to be extracted and indicated to undergo r-CAIS were evaluated. The patients had positioning markers installed in the oral cavity and underwent cone-beam computed tomography (CBCT). Subsequently, minimally invasive tooth extractions were performed, and an individualised surgical plan was generated in the robotic software. After marker registration, implantation surgery was performed by the robotic arm under the supervision and assistance of the surgeons. Finally, the deviations between the planned and placed implants were evaluated based on preoperative and postoperative CBCT data.

RESULTS

A total of 12 patients were evaluated. No adverse events occurred during the surgery. The mean global coronal, global apical, and angular deviations were 0.46 ± 0.15 mm (95%CI:0.36 to 0.56 mm), 0.46 ± 0.14 mm (95%CI:0.37 to 0.54 mm), and 1.05 ± 0.55° (0.69 to 1.40°), respectively.

CONCLUSIONS

Under the limited conditions of this study, the r-CAIS exhibited high accuracy in posterior teeth IIP surgery. Further multicentre randomised controlled studies are required to confirm the feasibility of this technology.

Comparison of the positional accuracy of robotic guided dental implant placement with static guided and dynamic navigation systems: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The development of robotic computer assisted implant surgery (r-CAIS) offers advantages, but how the positional accuracy of r-CAIS compares with other forms of guided implant surgery remains unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the positional accuracy of r-CAIS and to compare the positional accuracy of r-CAIS with s-CAIS and d-CAIS.

MATERIAL AND METHODS

Five databases were systematically searched by 2 independent reviewers for articles published before May 2023. A manual search was also performed. Articles evaluating the positional accuracy of r-CAIS were included. The Cochrane risk of bias tool was used for the clinical studies, whereas the QUIN tool was used for the in vitro studies. A meta-analysis was performed to compare the positional accuracy of r-CAIS with d-CAIS.

RESULTS

Thirteen studies were included, with 9 in vitro studies, 4 clinical studies, and a total of 920 dental implants. A high risk of bias was noted in 6 studies and low to moderate in 7 studies. R-CAIS showed greater accuracy for the coronal, apical, and angular deviations compared with d-CAIS. (-0.17 [-0.24, 0.09], (P<.001); -0.21 [-0.36, -0.06] (P=.006), and -1.41 [-1.56, -1.26] (P<.001)) CONCLUSIONS: R-CAIS can provide improved positional accuracy compared with d-CAIS when considering coronal, apical, and angular deviations. However, evidence to compare the positional accuracy of r-CAIS with s-CAIS was insufficient. These results should be interpreted with caution because of the limited data and the bias noted in several studies.

Accuracy of an autonomous dental implant robotic system in placing tilted implants for edentulous arches

STATEMENT OF PROBLEM

Accurate placement of tilted implants is essential as they are typically close to important anatomic structures. Inaccurate implant position may damage those structures and affect outcomes.

PURPOSE

The purpose of this in vitro study was to compare the accuracy and efficiency of an autonomous dental implant robotic (ADIR) system and a static computer-assisted implant surgery (sCAIS) system in placing tilted implants in edentulous patients.

MATERIAL AND METHODS

Ten 3-dimensionally (3D) printed edentulous mandibular casts were assigned to 1 of 2 groups (ADIR and sCAIS). The coronal, apical, and angular deviations of the placement of tilted implants, preoperative preparation time, and surgical time were compared between the 2 groups. The paired samples t test and the independent samples t test were used to compare the groups (α=.05).

RESULTS

The mean ±standard deviation of coronal, apical, and angular deviation in the ADIR group and sCAIS group were 0.47 ±0.06 mm versus 1.09 ±0.11 mm, 0.47 ±0.05 mm versus 1.53 ±0.14 mm, and 0.91 ±0.82 degrees versus 2.83 ±0.55 degrees, respectively. The deviations of the tilted implant positions in the ADIR were relatively small and significantly different from those of sCAIS (P<.05). The preoperative preparation time of the ADIR group was significantly longer than that of the sCAIS group (P<.001), and the surgical time for the 2 groups was statistically similar (P=.259).

CONCLUSIONS

Compared with the sCAIS system, the deviation of tilted implants in the ADIR group was smaller, but the preoperative preparation time was longer. The results indicated that using the ADIR for tilted implantation can lead to more accurate implantation positions and reduce the occurrence of complications. However, it is time consuming, and the workflow should be simplified to improve efficiency.

Digital robot-assisted minimally invasive impacted tooth extraction: A case report

Objective

This study investigated the clinical effects and applicability of minimally invasive impacted teeth extraction using digital robots.

Methods

A marker was bonded to the non-surgical area before surgery. A Cone-Beam Computed Tomography (CBCT) scan was obtained and uploaded to the robot software to determine the drilling position of the ring drill. During the surgery, the robot arm automatically navigated to a predetermined position, and the ring drill removed part of the bone tissue and exposed and extracted the impacted teeth. Finally, the surgeon tightly sutured the wounds to the surgical area.

Results

Three minimally invasive extractions of impacted teeth with robotic assistance were performed without complications. The surgical area showed good healing during the one-month follow-up examination.

Conclusions

Digital robot-assisted minimally invasive extraction of impacted teeth is a highly feasible clinical procedure as it minimises trauma to the surgical area and protects the surrounding blood vessels and nerve bundles, making it a safe and valuable technique with significant potential for clinical application.

Development and validation of a collaborative robotic platform based on monocular vision for oral surgery: an in vitro study

PURPOSE

Surgical robots effectively improve the accuracy and safety of surgical procedures. Current optical-navigated oral surgical robots are typically developed based on binocular vision positioning systems, which are susceptible to factors including obscured visibility, limited workplace, and ambient light interference. Hence, the purpose of this study was to develop a lightweight robotic platform based on monocular vision for oral surgery that enhances the precision and efficiency of surgical procedures.

METHODS

A monocular optical positioning system (MOPS) was applied to oral surgical robots, and a semi-autonomous robotic platform was developed utilizing monocular vision. A series of vitro experiments were designed to simulate dental implant procedures to evaluate the performance of optical positioning systems and assess the robotic system accuracy. The singular configuration detection and avoidance test, the collision detection and processing test, and the drilling test under slight movement were conducted to validate the safety of the robotic system.

RESULTS

The position error and rotation error of MOPS were 0.0906 ± 0.0762 mm and 0.0158 ± 0.0069 degrees, respectively. The attitude angle of robotic arms calculated by the forward and inverse solutions was accurate. Additionally, the robot's surgical calibration point exhibited an average error of 0.42 mm, with a maximum error of 0.57 mm. Meanwhile, the robot system was capable of effectively avoiding singularities and demonstrating robust safety measures in the presence of minor patient movements and collisions during vitro experiment procedures.

CONCLUSION

The results of this in vitro study demonstrate that the accuracy of MOPS meets clinical requirements, making it a promising alternative in the field of oral surgical robots. Further studies will be planned to make the monocular vision oral robot suitable for clinical application.

Robot-assisted surgery for dental implant placement: A narrative review

OBJECTIVE

To determine the current status and accuracy of robotic computer-assisted implant surgery (CAIS) applications by examining the associated clinical and experimental outcomes.

DATA AND SOURCES

PubMed, Medline, and Cochrane Library databases were searched for relevant studies published between January 2000 and November 2023, and focusing on robotic CAIS in dental implant surgery. All search results were then manually reviewed to identify only the pertinent articles. Only in vitro and clinical studies were included in this narrative review, with implant placement accuracy considered the main outcome.

RESULT

Based on our inclusion and exclusion criteria, we included 21 studies (with 1085 implant sites); of them, 8 were clinical studies, 12 were in vitro studies, and 1 included both an in vitro study and a case series. The ranges of the mean implant shoulder, apical, and angular deviations were respectively 0.43-1.04 mm, 0.53-1.06 mm, and 0.77°-3.77° in the clinical studies and 0.23-1.04 mm, 0.24-2.13 mm, and 0.43°-3.78° in the in vitro studies, respectively.

CONCLUSION

The accuracy of robotic CAIS in dental implant procedures appears to be within the clinically acceptable ranges. However, further relevant clinical trials validating the existing evidence are needed.

CLINICAL SIGNIFICANCE

Robotic CAIS can achieve clinically acceptable implant placement accuracy. This innovative technology may improve the precision and success rates of dental implant procedures, with benefit for surgeons and patients.

A robotic system for transthoracic puncture of pulmonary nodules based on gated respiratory compensation

BACKGROUND AND OBJECTIVE

With the urgent demands for rapid and precise localization of pulmonary nodules in procedures such as transthoracic puncture biopsy and thoracoscopic surgery, many surgical navigation and robotic systems are applied in the clinical practice of thoracic operation. However, current available positioning methods have certain limitations, including high radiation exposure, large errors from respiratory, complicated and time-consuming procedures, etc. METHODS: To address these issues, a preoperative computed tomography (CT) image-guided robotic system for transthoracic puncture was proposed in this study. Firstly, an algorithm for puncture path planning based on constraints from clinical knowledge was developed. This algorithm enables the calculation of Pareto optimal solutions for multiple clinical targets concerning puncture angle, puncture length, and distance from hazardous areas. Secondly, to eradicate intraoperative radiation exposure, a fast registration method based on preoperative CT and gated respiration compensation was proposed. The registration process could be completed by the direct selection of points on the skin near the sternum using a hand-held probe. Gating detection and joint optimization algorithms are then performed on the collected point cloud data to compensate for errors from respiratory motion. Thirdly, to enhance accuracy and intraoperative safety, the puncture guide was utilized as an end effector to restrict the movement of the optically tracked needle, then risky actions with patient contact would be strictly limited.

RESULTS

The proposed system was evaluated through phantom experiments on our custom-designed simulation test platform for patient respiratory motion to assess its accuracy and feasibility. The results demonstrated an average target point error (TPE) of 2.46 ± 0.68 mm and an angle error (AE) of 1.49 ± 0.45° for the robotic system.

CONCLUSIONS

In conclusion, our proposed system ensures accuracy, surgical efficiency, and safety while also reducing needle insertions and radiation exposure in transthoracic puncture procedures, thus offering substantial potential for clinical application.

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

OBJECTIVES

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

DATA

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

SOURCES

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

RESULTS

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

CONCLUSIONS

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

CLINICAL SIGNIFICANCE

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

Ultraviolet disinfection (UV-D) robots: bridging the gaps in dentistry

Maintaining a microbe-free environment in healthcare facilities has become increasingly crucial for minimizing virus transmission, especially in the wake of recent epidemics like COVID-19. To meet the urgent need for ongoing sterilization, autonomous ultraviolet disinfection (UV-D) robots have emerged as vital tools. These robots are gaining popularity due to their automated nature, cost advantages, and ability to instantly disinfect rooms and workspaces without relying on human labor. Integrating disinfection robots into medical facilities reduces infection risk, lowers conventional cleaning costs, and instills greater confidence in patient safety. However, UV-D robots should complement rather than replace routine manual cleaning. To optimize the functionality of UV-D robots in medical settings, additional hospital and device design modifications are necessary to address visibility challenges. Achieving seamless integration requires more technical advancements and clinical investigations across various institutions. This mini-review presents an overview of advanced applications that demand disinfection, highlighting their limitations and challenges. Despite their potential, little comprehensive research has been conducted on the sterilizing impact of disinfection robots in the dental industry. By serving as a starting point for future research, this review aims to bridge the gaps in knowledge and identify unresolved issues. Our objective is to provide an extensive guide to UV-D robots, encompassing design requirements, technological breakthroughs, and in-depth use in healthcare and dentistry facilities. Understanding the capabilities and limitations of UV-D robots will aid in harnessing their potential to revolutionize infection control practices in the medical and dental fields.

Accuracy of a Novel Semi-Autonomous Robotic-Assisted Surgery System for Single Implant Placement: a Case Series

OBJECTIVE

This study aimed to evaluate the accuracy of dental implant placement at single-tooth sites using a novel semi-autonomous robotic-assisted surgery system (sa-RASS).

METHODS

Patients with single missing teeth were included. Cone-beam computed tomography (CBCT) was performed prior to surgery using a U-shaped silicone tube to develop a virtual implant placement and drilling plan. The sa-RASS was used for implant osteotomy and placement in conjunction with a surgeon. Cone-beam computed tomography data were utilised to evaluate deviations between planned and placed implants using a three-dimensional Slicer software. Data were analysed using the t-test and analysis of variance. Statistical significance was considered at P<0.05.

RESULTS

Nineteen implants were placed using the sa-RASS. No adverse events or complications were observed during the surgery. Mean ± standard deviations between planned and postoperative implant positions were 0.90 ± 0.41 mm at the platform, 1.04 ± 0.47 mm at the apex, and 3.37 ± 1.51° for angulation. In a lateral direction, deviations were 0.72 ± 0.38 mm and 0.88 ± 0.47 mm at the platform and apex, respectively. Deviations in depth were all <1mm at both the platform (0.46 ± 0.33 mm) and apex (0.45 ± 0.32 mm). The apex deviation was greater than that at the platform (p = 0.036 < 0.05), mainly in the lateral distance (p = 0.037 < 0.05).

CONCLUSIONS

The current study illustrate that this robotic implant system is sufficiently accurate for single-tooth implant placement.

CLINICAL SIGNIFICANCE

This study provides significant evidence to support the use of sa-RASS as a potential alternative to static guided surgery and dynamic navigation, in dental implant surgery.

Accuracy and efficiency of robotic dental implant surgery with different human-robot interactions: An in vitro study

OBJECTIVES

This study aims to compare the surgical efficiency (preparation and operation time) and accuracy of implant placement between robots with different human-robot interactions.

METHODS

The implant robots were divided into three groups: semi-active robot (SR), active robot (AR) and passive robot (PR). Each robot placed two implants (#31 and #36) on a phantom, practising 10 times. The surgical efficiency and accuracy of implant placement were then evaluated.

RESULTS

Sixty implants were placed in 30 phantoms. The mean preparation times for the AR, PR and SR groups were 3.85 ± 0.17 min, 2.14 ± 0.06 mins and 1.65 ± 0.19 mins, respectively. The mean operation time of the PR group (3.76 ± 0.59 min) was shorter that of than the AR (4.89 ± 0.70 mins) and SR (4.59 ± 0.56 min) groups (all P < 0.001). The operation time of the AR group in the anterior region (4.47 ± 0.31 min) was longer than that of the SR group (4.07 ± 0.10 min) (P = 0.007). The mean coronal, apical and axial deviations of the PR group (0.40 ± 0.12 mm, 0.49 ± 0.13 mm, 0.96 ± 0.22°) were higher than those of the AR (0.23 ± 0.11 mm, 0.24 ± 0.11 mm, 0.54 ± 0.20 °) (all P < 0.001) and SR (0.31 ± 0.10 mm, 0.36 ± 0.12 mm, 0.43 ± 0.14 °) groups (P = 0.044, P = 0.002, and P < 0.001, respectively).

CONCLUSIONS

Human-robot interactions affect the efficiency of implant surgery. Active and semi-active robots show comparable implant accuracy. However, the implants placed by the passive robot show higher deviations.

CLINICAL SIGNIFICANCE

This in vitro study preliminarily demonstrates that implant placement is accurate when using implant robots with different human-robot interactions. However, different human-robot interactions have variable surgical efficiencies.

A collaborative robotic platform for sensor-aware fibula osteotomies in mandibular reconstruction surgery

Precision and safety are crucial in performing fibula osteotomy during mandibular reconstruction with free fibula flap (FFF). However, current clinical methods, such as template-guided osteotomy, have the potential to cause damage to fibular vessels. To address the challenge, this paper introduces the development of the surgical robot for fibula osteotomies in mandibular reconstruction surgery and propose an algorithm for sensor-aware hybrid force-motion control for safe osteotomy, which includes three parts: osteotomy motion modeling from surgeons' demonstrations, Dynamic-system-based admittance control and osteotomy sawed-through detection. As a result, the average linear variation of the osteotomized segments was 1.08±0.41mm, and the average angular variation was 1.32±0.65∘. The threshold of osteotomy sawed-through detection is 0.5 at which the average offset is 0.5mm. In conclusion, with the assistance of surgical robot for mandibular reconstruction, surgeons can perform fibula osteotomy precisely and safely.

Design and implementation of a surgical planning system for robotic assisted mandible reconstruction with fibula free flap

PURPOSE

Free fibula flap is the gold standard for the treatment of mandibular defects. However, the existing preoperative planning protocol is cumbersome to execute, costly to learn, and poorly collaborative with the robot-assisted cutting of the fibular osteotomy plane.

METHODS

A surgical planning system for robotic assisted mandibular reconstruction with fibula free flap is proposed in this study. A fibular osteotomy planning algorithm is presented so that the virtual surgical planning of the fibular osteotomy segments can be obtained automatically with selected mandibular anatomical landmarks. The planned osteotomy planes are then converted into the motion path of the robotic arm, and the automatic fibula osteotomy is completed under optical navigation.

RESULTS

Surgical planning was performed on 35 patients to verify the feasibility of our system's virtual surgical planning module, with an average time of 13 min. Phantom experiments were performed to evaluate the reliability and stability of this system. The average distance and angular deviations of the osteotomy planes are 1.04 ± 0.68 mm and 1.56 ±1.10°, respectively.

CONCLUSIONS

Our system can achieve not only precise and convenient preoperative planning, but also safe and reliable osteotomy trajectory. The clinical applications of our system for mandibular reconstruction surgery are expected soon.

Dental Implant Navigation System Based on Trinocular Stereo Vision

Traditional dental implant navigation systems (DINS) based on binocular stereo vision (BSV) have limitations, for example, weak anti-occlusion abilities, as well as problems with feature point mismatching. These shortcomings limit the operators’ operation scope, and the instruments may even cause damage to the adjacent important blood vessels, nerves, and other anatomical structures. Trinocular stereo vision (TSV) is introduced to DINS to improve the accuracy and safety of dental implants in this study. High positioning accuracy is provided by adding cameras. When one of the cameras is blocked, spatial positioning can still be achieved, and doctors can adjust to system tips; thus, the continuity and safety of the surgery is significantly improved. Some key technologies of DINS have also been updated. A bipolar line constraint algorithm based on TSV is proposed to eliminate the feature point mismatching problem. A reference template with active optical markers attached to the jaw measures head movement. A T-type template with active optical markers is used to obtain the position and direction of surgery instruments. The calibration algorithms of endpoint, axis, and drill are proposed for 3D display of the surgical instrument in real time. With the preoperative path planning of implant navigation software, implant surgery can be carried out. Phantom experiments are carried out based on the system to assess the feasibility and accuracy. The results show that the mean entry deviation, exit deviation, and angle deviation are 0.55 mm, 0.88 mm, and 2.23 degrees, respectively.

Ultrasound image guided and mixed reality-based surgical system with real-time soft tissue deformation computing for robotic cervical pedicle screw placement

Cervical pedicle screw (CPS) placement surgery remains technically demanding due to the complicated anatomy with neurovascular structures. State-of-the-art surgical navigation or robotic systems still suffer from the problem of hand-eye coordination and soft tissue deformation. In this study, we aim at tracking the intraoperative soft tissue deformation and constructing a virtual physical fusion surgical scene, and integrating them into the robotic system for CPS placement surgery. Firstly, we propose a real-time deformation computation method based on the prior shape model and intraoperative partial information acquired from ultrasound images. According to the generated posterior shape, the structure representation of deformed target tissue gets updated continuously. Secondly, a hand tremble compensation method is proposed to improve the accuracy and robustness of the virtual-physical calibration procedure, and a mixed reality based surgical scene is further constructed for CPS placement surgery. Thirdly, we integrate the soft tissue deformation method and virtual-physical fusion method into our previously proposed surgical robotic system, and the surgical workflow for CPS placement surgery is introduced. We conducted phantom and animal experiments to evaluate the feasibility and accuracy of the proposed system. Our system yielded a mean surface distance error of 1.52 ± 0.43 mm for soft tissue deformation computing, and an average distance deviation of 1.04 ± 0.27 mm for CPS placement. Results demonstrated that our system involves tremendous clinical application potential. Our proposed system promotes the efficiency and safety of the CPS placement surgery.

An image-guided hybrid robot system for dental implant surgery

PURPOSE

Dental implant surgery is an effective method for remediating the loss of teeth. Robot is expected to increase the accuracy of dental implant surgery. However, most of them are industrial serial robot, with low stiffness and non-unique inverse kinematic solution, which may reduce the success rate and safety of robotic surgery. Compared to serial robot, parallel robot is more stiffness and has unique inverse kinematic. However, its workspace is small, which may not meet surgical requirements. Therefore, a novel hybrid robot dedicated to dental implant is proposed.

METHODS

The hybrid robot is composed of three translation joints, two revolute joints, and Stewart parallel manipulator. Stewart is used for performing surgical operation, while the joints are used for enlarging the workspace of Stewart. In order to ensure the safety of robot motion, physical human-robot interaction based on a variable admittance controller is applied in the robotic system. In addition, considering the small workspace of Stewart, an optimal model is proposed to minimize the joint movement of Stewart in adjusting the orientation of drill bit.

RESULTS

Phantom experiments were carried out based on the prototype robot. In the experiments, the optimal model could be solved after 20 iterations, finding an ideal joint configuration. The proposed variable admittance controller could enhance comfort level effectively. The accuracy of robot is evaluated by angle, entry and exit deviation, which are 0.74 ± 0.25°, 0.93 ± 0.28 mm, and 0.96 ± 0.23 mm, respectively.

CONCLUSION

The phantom experiments validate the functionality of the proposed hybrid robot. The satisfactory performance makes it more widely used in the practical dental implant surgery in the future.