Accuracy of an autonomous dental implant robotic system in partial edentulism: A pilot clinical study.

OBJECTIVES: Robots are increasingly being used for surgical procedures in various specialties. However, information about the accuracy of robot-assisted dental implant surgery is lacking. This pilot clinical study aimed to investigate the accuracy of an autonomous dental implant robotic (ADIR) system in partially edentulous cases. MATERIAL AND METHODS: The ADIR system was used to place a total of 20 implants in 13 participants. Implant deviation from the planned positions was assessed to determine accuracy. The entry, apex, and angular deviations were described as means ± standard deviation. A two-sample t test was used to compare implant deviation between the flap and flapless groups and between maxillary and mandibular implants (α = .05). RESULTS: The entry, apex, and angular deviations were 0.65 ± 0.32 mm, 0.66 ± 0.34 mm, and 1.52 ± 1.01°, respectively, with no statistically significant difference between the flap and flapless approaches (P > .05). No adverse events were encountered in any of the participants. CONCLUSIONS: DIR accuracy in this clinical series was comparable to that reported for static and dynamic computer-assisted implant surgery. Robotic computer-assisted implant surgery may be useful for dental implant placement, potentially improving the quality and safety of the procedure. CLINICAL RELEVANCE: The findings of this study showed that the ADIR system could be useful for dental implant surgery.

Accuracy of different registration areas using active and passive dynamic navigation systems in dental implant surgery: An in vitro study.

OBJECTIVES: To gauge the relative accuracy of the use of passive and active dynamic navigation systems when placing dental implants, and to determine how registration areas affect the performance of these systems. MATERIALS AND METHODS: Eighty implants were assigned to be placed into 40 total resin mandible models missing either the left or right first molars using either passive or active dynamic navigation system approaches. U-shaped tube registration devices were fixed in the edentulous site for 20 models each on the left or right side. Planned and actual implant positions were superimposed to assess procedural accuracy, and parameters including 3D entry deviation, angular deviation, and 3D apex deviation were evaluated with Mann-Whitney U tests and Wilcoxon signed-rank tests. RESULTS: Respective angular, entry, and apex deviation values of 1.563 ± 0.977°, 0.725 ± 0.268 mm, and 0.808 ± 0.284 mm were calculated for all included implants, with corresponding values of 1.388 ± 1.090°, 0.789 ± 0.285 mm, and 0.846 ± 0.301 mm in the active group and 1.739 ± 0.826°, 0.661 ± 0.236 mm, and 0.769 ± 0.264 mm in the passive group. Only angular deviation differed significantly among groups, and the registration area was not associated with any significant differences among groups. CONCLUSIONS: Passive and active dynamic navigation approaches can achieve comparable in vitro accuracy. Registration on one side of the missing single posterior tooth area in the mandible can complete single-tooth implantation on both sides of the posterior teeth, highlighting the promise of further clinical research focused on this topic.

Accuracy of 3 calibration methods of computer-assisted dynamic navigation for implant placement: An in vitro study.

STATEMENT OF PROBLEM: Dynamic navigation for implant placement has been reported to be more accurate than freehand surgery. However, the accuracy of the calibration methods used for navigation in partially edentulous individuals with distal extensions remains unknown. PURPOSE: The purpose of this in vitro study on dental models was to evaluate the accuracy of 3 calibration methods of dynamic navigation for implant placement in the distal extension of partially edentulous arches. MATERIAL AND METHODS: Eleven standardized polyurethane mandibular models with distal extensions were prepared. The left first molar, second molar, and second premolar from each model (33 tooth sites) were randomly assigned to 1 of the 3 calibration methods: U-shaped tube embedded with radiopaque markers, anatomic tooth cusps, and bone markers with the random number table method. Preoperative and postoperative cone beam computed tomography images were obtained for deviation analyses. The primary outcomes were 3-dimensional (3D) deviation at the implant platform and apex and angular deviation. Differences among the test groups were analyzed by using a 1-way analysis of variance (ANOVA) and the least significant difference (LSD) post hoc test (α=.05). RESULTS: The mean ±standard deviation 3D deviations were 0.78 ±0.34, 1.86 ±0.91, and 1.44 ±0.57 mm at the implant platform and 0.79 ±0.35, 2.19 ±1.01, and 1.49 ±0.50 mm at the apex in the U-shaped tube, tooth cusp, and bone marker groups, respectively. The 3D deviations at the implant platform and apex were significantly different among the groups (P<.01). The angular deviation was 1.36 ±0.54, 2.95 ±2.07, and 2.92 ±2.45 degrees, with no significant differences among the groups (P=.092). CONCLUSIONS: In the dynamic navigation of implant placement in the distal extension of partially edentulous arches, the U-shaped tube calibration with radiopaque markers was more accurate than the anatomic tooth cusp or bone marker calibration.

Artificially designed hepatitis B virus core particles composed of multiple epitopes of type A and O foot-and-mouth disease virus as a bivalent vaccine candidate.

Recently, many countries, including China, have experienced a series of type A and O foot-and-mouth disease virus (FMDV) epidemics, causing serious economic losses. Although concerns about the safety of inactivated FMD vaccines have been raised, the development of a safe and effective subunit vaccine is necessary. We constructed two chimeric virus-like particles (VLPs; rHBc/AO and rHBc/AOT VLPs) displaying tandem repeats of B cell epitopes (VP1 residue 134-161 and 200-213) derived from type A and O FMDV and one T cell epitope (3 A residue 21-35) using the truncated hepatitis B virus core (HBc) carrier. Our results indicate that the chimeric HBc can self-assemble into VLPs with these FMDV epitopes displayed on the surface. Immunization with the chimeric VLPs induced specific IgG and neutralization antibodies against type A and O FMDV in mice. Compared with the commercial type A/O FMDV bivalent inactivated vaccine, rHBc/AO and rHBc/AOT VLPs significantly stimulated the production of Th1 type cytokines (IFN-γ and IL-2), whereas Th2 cytokine production (IL-4 and IL-10) was decreased. Compared with rHBc/AO, rHBc/AOT induced increased Th2 cytokine and specific IgG production. These results demonstrate that the VLPs constructed in the current study induced both humoral and cellular immune responses and may represent potential bivalent VLP vaccines targeting both FMDV type A and O strains.

Effects of mesenchymal stem cells and their exosomes on the healing of large and refractory macular holes.

PURPOSE: To assess the efficacy of mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-Exos) to promote the healing of large and refractory macular holes (MHs). METHODS: Seven patients (age 51-75 years old) with large and long-standing idiopathic MHs underwent vitrectomy, internal limiting membrane peeling, MSC (two patients) or MSC-Exo (five patients) intravitreal injection, and heavy silicon oil, air, 20% SF6, or 14% C3F8 tamponade. The MSCs were isolated from human umbilical cord tissue, and MSC-Exos were isolated from the supernatants of cultured MSCs using sequential ultracentrifugation. RESULTS: Five eyes underwent pars plana vitrectomy (PPV) only, while two underwent PPV combined with cataract surgery. Six MHs were closed, while one remained in a flat-open state. The best-corrected visual acuity (BCVA) was improved in five patients with MH closure and remained unchanged in one patient with MH closure who had a 4-year history of MH. A fibrotic membrane was observed on the surface of the retina in one patient who underwent MSC therapy. One patient who received a higher dose of MSC-Exos exhibited an inflammatory reaction. CONCLUSIONS: MSC and MSC-Exo therapy may promote functional and anatomic recovery from MH. MSC-Exo therapy may be a useful and safe method for improving the visual outcomes after surgery for refractory MHs.

Assessment of the Accuracy of Two Different Dynamic Navigation System Registration Methods for Dental Implant Placement in the Posterior Area: An In Vitro Study.

Purpose: To compare the U-tube and cusp dynamic navigation system registration methods in the use of dental implant placement, and to assess the influence of the location of missing teeth on these registrations. Methods: 32 resin mandible models and 64 implants were utilized, with implants being placed using one of the two registration methods selected at random. Accuracy was measured through the superimposition of the final and planned implant positions. Angular deviation, 3D entry deviation, and 3D apex deviation were analyzed. Results: The overall mean 3D deviation was 1.089 ± 0.515 mm at the entry point and 1.174 ± 0.531 mm at the apex point, and mean angular deviation was 1.970 ± 1.042 degrees. No significant difference (p > 0.05) was observed when comparing these two registration methods. However, the U-tube method showed significant difference when assessing the location of missing teeth (without distal-extension absence and distal-extension absence), whereas cusp registration was unaffected. Conclusions: Both the U-tube and cusp dynamic navigation system registration methods are accurate when implemented in vitro. Besides, the cusp registration technique can also overcome several of the limitations of the U-tube approach and the accuracy of it was not influenced by the location of the missing teeth, highlighting it as a method worthy of further clinical research.

Analysis of the accuracy of a dynamic navigation system when performing dental implant surgery with transcrestal sinus floor elevation: A pilot study.

Background/purpose: The success of transcrestal sinus floor elevation (TSFE) is primarily reliant upon the experience of the surgeon owing to the limited operative visibility. To evaluate the accuracy associated with the use of a dynamic navigation system when conducting posterior maxilla implant surgery with TSFE. Materials and methods: Twenty-eight implants were placed in 28 patients requiring implantation in the posterior maxilla via a TSFE approach. The drills were used to access the planned position (within 1 mm of the bottom of the maxillary sinus floor) under dynamic navigation system. TSFE was then accomplished using osteotomes and a piezoelectric device. Lastly, the implant was inserted under the dynamic navigation. Three effective deviations between planned and actual implant placement were then measured including angular deviation (AD, degrees), entry point horizontal deviation (EPHD, mm), and apical point horizontal deviation (APHD, mm). Results: The AD, EPHD, and APHD between the planned and actual implant placement were 3.656 ± 1.665°, 1.073 ± 0.686 mm, and 1.086 ± 0.667 mm, respectively. Premolar site AD values were less than those for molar sites (P = 0.004). No significant differences in these outcomes were observed in different surgeons. Obvious sinus perforation was not detected by immediate postoperative cone beam computed tomography imaging. Conclusion: The accuracy associated with using a dynamic navigation system when conducting posterior maxilla implant surgery via a TSFE approach using piezoelectric devices was comparable. This technique thus achieved appropriate interventional precision and safety while decreasing the morbidity associated with the TSFE approach.

Proposal and Validation of a New Nonradiological Method for Postoperative Three-Dimensional Implant Position Analysis Based on the Dynamic Navigation System: An In Vitro Study.

PURPOSE: To propose a novel, radiation-free method for postoperative three-dimensional (3D) position analysis of dental implants based on the dynamic navigation system (DNS) and evaluate its accuracy in vitro. METHODS: A total of 60 implants were digitally planned and then placed in the standardized plastic models with a single-tooth gap and a free-end gap under the guidance of the DNS. Postoperative 3D positions of the inserted implants were evaluated using specially designed navigation-based software, and its datasets were superimposed onto those of cone beam computed tomography (CBCT) for accuracy analyses. Deviations at the coronal, apical, and angular levels were measured and statistically analyzed. RESULTS: The mean 3D deviation was 0.88 ± 0.37 mm at the entry point and 1.02 ± 0.35 mm at the apex point. The mean angular deviation was 1.83 ± 0.79 degrees. No significant differences were noted in the deviations between implants placed in the single-tooth gap and the free-end situation (p > 0.05) or between different tooth positions at distal extensions (p > 0.05). CONCLUSIONS: This non-radiographic method provides facile, efficient, and reliable postoperative implant position evaluation and may be a potential substitute for CBCT, particularly for implants placed under the guidance of dynamic navigation.

Comparison of the accuracy of two different dynamic navigation system registration methods for dental implant placement: A retrospective study.

BACKGROUND: Dynamic navigation approaches are widely employed in the context of implant placement surgery, with registration being integral to the accuracy of such navigation. Relatively few studies to date, however, have compared different registration approaches, and such a comparison has the potential to guide the development of more accurate and reliable clinical registration methodology. PURPOSE: This study was developed to compare the accuracy of dynamic navigation-based dental implant placement conducted using either U-tube or cusp registration methods. MATERIALS AND METHODS: Medical records from all patients that had undergone implant surgery between August 2019 and October 2020 in the First Clinical Division of the Peking University Hospital of Stomatology were retrospectively reviewed, with 64 patients and 99 implants ultimately meeting with study inclusion criteria. Implant placement accuracy was gauged via the superimposition of the planned implant position in preoperative cone-beam computed tomography (CBCT) images with the true postoperative implant position in postoperative CBCT images. Accuracy was measured based upon the angular deviation, entry deviation (3-dimensional [3D] deviation in the coronal aspect of the alveolar ridge), and apex deviation (3D deviation in the apical area of the implant) when comparing these two positions. RESULTS: The angular deviation, entry deviation, and apex deviation of all analyzed implants were 3.29 ± 0.17°, 1.29 ± 0.07 mm, and 1.43 ± 0.08 mm, respectively, while in the cusp registration group these respective values were 3.25 ± 1.58°, 1.28 ± 0.60 mm, and 1.34 ± 0.63 mm as compared to 3.35 ± 1.78°, 1.30 ± 0.78 mm, 1.55 ± 0.9 mm in the U-tube group, respectively. No significant differences in accuracy were observed when comparing these two registration techniques. CONCLUSION: Dynamic computer-assisted surgical systems can facilitate accurate implantation, and both the U-tube and cusp registration methods exhibit similar levels of accuracy. As the cusp registration technique can overcome some of the limitations of the U-tube strategy without the need for an additional registration device, it may be more convenient for clinical use and warrants further research.

The impact of autologous concentrated growth factors on the alveolar ridge preservation after posterior tooth extraction: A prospective, randomized controlled clinical trial.

BACKGROUND: Alveolar ridge preservation can effectively decrease alveolar ridge resorption following tooth extraction, but it can be limited by reducing new bone formation and residual bone graft material. Efforts to develop more efficacious approaches are thus an area of active research. PURPOSE: To assess the impact of autologous concentrated growth factors (CGF) on alveolar ridge absorption and osteogenesis following posterior tooth extraction. MATERIALS AND METHODS: Fifty patients were randomly assigned to have extraction sockets treated with CGF or no treatment. At 10 days, 1 month, and 3 months postextraction, soft tissue color and texture were examined and evaluated with healing score. Cone-beam computed tomography (CBCT) scans were performed before and 3 months after extraction, while radiographic analyses were used to assess vertical and horizontal bone changes. Bone samples were collected from the extraction sockets during implant placement, and micro-computed tomography (micro-CT) scans and histological analysis were performed to evaluate new bone formation. t-Test or Mann-Whitney U test was used to compare data and the level of statistical significance was set at 0.05 for all analyses. RESULTS: Forty-six patients completed the trial. Sockets in the experimental group exhibited significantly better healing score on Day 10 postextraction relative to the control group, whereas comparable healing was observed in both groups at 1 and 3 months postextraction. Experimental group exhibited reduced vertical bone changes relative to the control (p < 0.05). Significant reductions were observed in ridge width changes at 1 and 2 mm apical to the crest (p < 0.05), although differences at 3 and 5 mm apical to the crest were not significant. Significant differences of bone mineral density (BMD) and microarchitecture of trabecular bone were observed via micro-CT analyses, and the experimental group had better results. CONCLUSION: CGF application following posterior tooth extraction may reduce vertical and horizontal bone resorption and promote new bone formation.

Enhanced efficacy of a multi-epitope vaccine for type A and O foot­and-mouth disease virus by fusing multiple epitopes with Mycobacterium tuberculosis heparin-binding hemagglutinin (HBHA), a novel TLR4 agonist.

Foot-and-mouth disease (FMD) is an acute, severe, and highly contagious disease that affects cloven-hoofed animals and can lead to serious economic losses and social effects. Therefore, a safe and effective subunit vaccine is required to prevent and control FMD. Dendritic cells (DCs) are a type of professional antigen presenting cell (APC). Immature DCs are typically stimulated by various adjuvants via immune receptors (e.g., toll-like receptor 4 [TLR4]), which activate DCs to induce their maturation. TLR4 has been well-established to induce both innate and adaptive immune responses to various external microbial or internal damage-related molecular patterns. In this study, the multi-epitope immunogen, HAO, of foot-and-mouth disease virus (FMDV) serotypes A and O was fused with the recombinant protein, heparin-binding hemagglutinin (HBHA), a novel TLR4 agonist, to obtain a new recombinant fusion protein, termed HAO-HBHA. HAO-HBHA was found to be highly efficient at activating murine DCs by the TLR4 pathway, both in vitro and in vivo. HAO-HBHA elicited strong specific humoral immune responses detected with an ELISA and virus neutralizing antibody test (VNT). HAO-HBHA also elevated the cellular immune responses, as indicated by intracellular cytokine (e.g., IFN-γ, TNF-α, IL-4, IL-6, IL-10, and IL-12p70) expression in Th1 and Th2 cells. As a TLR4 agonist, HBHA has significant advantages for enhancing the immune efficacy of a FMDV serotype A and O bivalent multi-epitope vaccine. These findings provide a novel strategy for the development of a safe and effective multi-epitope vaccine candidate against FMDV and further extends the application of TLR agonist-based vaccine platforms.

[Normal occlusion study: using T-Scan III occlusal analysis system].

OBJECTIVE: To investigate the normal occlusal force distribution and the characteristics of the occlusion time at different occlusion position using T-Scan III occlusal analysis system. METHODS: Fifty-three volunteers with normal occlusion, including 29 males and 24 females, were included in this study. The average age was (25.9 ± 2.1) years old. T-Scan III occlusal analysis system was used to measure the occlusal force distribution and the time character of normal occlusion at intercuspal position, protrusive position, and lateral excursive position. RESULTS: At intercuspal position the left and right side molar teeth took the most part of force percentage, followed by (13.3 ± 4.3)%, (13.6 ± 5.4)%, (15.7 ± 7.1)%, (18.7 ± 7.5)% (6, 6, 7, 7); and 7654, 4567 took (61.3 ± 12.4)% force percentage; and the left and right sides took the respective percentages of (46.4 ± 7.0)%, (53.6 ± 7.0)%, the left side was significantly less than the right side(P < 0.05). At the protrusion position the region ( 21, 12) commitment to take the percentage of (85.1 ± 25.5)%. At left and right lateral position, 28% (13/46) and 30%(14/46) were cuspid-protected occlusion, and 33%(15/46) and 44%(20/46) were group functional occlusion, and 39%(18/46) and 26%(12/46) were multiple-protected occlusion. The average occlusion time was (0.34 ± 0.11) s, and disclusion time was (1.00 ± 0.39) s. CONCLUSIONS: At intercuspal position the region from first premolar to second molar teeth were the occlusal force centers, and the second molar is the most;.the force concentrated in the area ( 21, 12) at the protrusion position. The lateral occlusal pattern is multiformity.