International Journal of Dentistry最新文献

Background: Robot-assisted surgery is widely used in implant dentistry; however, the specific effects of implant site and bone quality on its accuracy require further elucidation.

Objective: This study aimed to evaluate the impact of implant site and bone quality on the accuracy of a single robotic-assisted implant placement method.

Methods: This retrospective analysis included 83 patients who received 173 implants via a robot-assisted system. Implants were categorized by site into upper-anterior (UA), upper-posterior (UP), lower-anterior (LA), and lower-posterior (LP) regions and by bone quality into Type I-II and Type III-IV. Postoperative accuracy was assessed by comparing the planned versus actual implant positions, measuring lateral coronal deviation (LCD), vertical coronal deviation (VCD), and global coronal deviation (GCD); lateral apical deviation (LAD), vertical apical deviation (VAD), and global apical deviation (GAD); and angular deviation (AD).

Results: When analyzed by implant site, the UA region demonstrated significantly larger vertical deviations (VCD and VAD) compared to the LP region (VCD: 0.99 ± 0.46 mm vs. 0.25 ± 0.53 mm, p  < 0.05; VAD: 0.95 ± 0.46 mm vs. 0.24 ± 0.53 mm, p  < 0.05). AD did not differ significantly among the various implant sites. Regarding bone quality, however, implants in Type III-IV bone exhibited significantly greater vertical deviations than those in Type I-II bone (VCD and VAD: 0.67 ± 0.56 mm vs. 0.27 ± 0.49 mm, p  < 0.05). Moreover, a trend toward a larger AD was also noted in Type III-IV bone (1.53 ± 1.09° vs. 1.18 ± 0.80°).

Conclusions: Both implant site and bone quality were found to influence the accuracy of the single robotic-assisted system.

Purpose: Analysis of facial morphology is a critical component in craniomaxillofacial prosthetics and surgery, serving purposes such as preoperative diagnosis, postoperative evaluation, and symmetry analysis. This study evaluated the accuracy of a structured-light 3D facial scanner for measuring facial soft tissues.

Methods: Twenty-one adult participants were included in this study. A conventional alginate facial impression was obtained from each participant. 3D facial images were also captured using a digital face scanner. Six facial landmarks were identified and recorded on each 3D facial image. The 3D facial scanner and linear caliper measurements on facial casts were employed to measure the distances between landmarks. The accuracy of the 3D facial scanner was evaluated through reliability analysis and paired t-tests.

Results: The mean absolute error of the scanner ranged from 0.18 to 0.44 mm, and the mean relative error ranged from 0.00 to 0.02. Of all the measurements, 69.3% were reproduced within 0.3 mm, and 86.1% within 0.5 mm. The intraclass correlation coefficient (ICC) for all distances was greater than 0.9, demonstrating high consistency. Paired t-test analysis indicated no systematic differences in mean measurements between the scanned images and the facial casts (p  > 0.05), except for one distance.

Conclusion: The findings suggest that the face scanner is a precise and reliable alternative for performing maxillofacial measurements.

Background: The current study aimed to evaluate the effectiveness of a camouflaged dental syringe in reducing dental anxiety and pain during maxillary infiltration anesthesia in children aged 6-9 years, compared to a conventional syringe.

Materials and methods: This randomized controlled clinical trial included healthy children aged 6-9 years who attended the Department of Paediatric Dentistry at Damascus University between December 2023 and May 2024. All participants required dental treatment in the maxilla involving buccal and palatal infiltration on one side. Participants were randomly assigned to two groups: Group A received local anesthesia with a conventional syringe using the tell-show-do (TSD) technique, and Group B received anesthesia with a camouflaged syringe using the same TSD approach. Dental anxiety was assessed using the facial image (FI) scale. Dental pain was assessed using the face, legs, activity, cry, consolability (FLACC) behavioral pain scale and changes in pulse rate as a physiological indicator for both pain and anxiety. Primary outcome measures were recorded at baseline (t ₀), after the TSD technique (t ₁), and after anesthesia procedure (t ₂).

Results: A total of 70 children (mean age = 7.34 years) were enrolled. The FI scale scores and pulse rates increased significantly overtime in both groups (p < 0.05), indicating heightened anxiety during the procedure. However, the camouflaged syringe group showed significantly lower FI scores at t ₁ (p = 0.001) and t ₂ (p = 0.005), indicating reduced anxiety levels compared to the control group. Similarly, the camouflaged syringe group reported a significantly lower FLACC score at t ₂ (p = 0.021), highlighting less reported pain. However, no significant differences were found in pulse rate across time points.

Conclusions: The use of a camouflaged syringe appears to be an effective strategy for reducing dental anxiety and pain in children undergoing local anesthetic injections in the maxillary arch. Trial Registration: ClinicalTrials.gov identifier: ISRCTN51025476.

Background: This study aimed to define the relation between posture and dimension of the tongue and different skeletal patterns in sagittal and vertical dimensions through cone beam computed tomography (CBCT).

Method: CBCT images of 225 patients (149 females and 76 males) with a mean age of 33 years were included in this retrospective study. The sample was divided into three groups: class I (100 patients), class II (100 patients), and class III (25 patients). For each sample, tongue length (TGL) and tongue height (TGH) along with its position were evaluated. For statistical analysis, one-way ANOVA, Tukey HSD, Welch's t-test, and Games-Howell test were performed. Also, to define the correlation between variables, Pearson and Spearman correlation coefficients were used.

Results: The mean TGH was significantly greater in the class III group compared to class I (p-value = 0.017) and class II groups (p-value = 0.002). The mean TGL was significantly greater in the class II group compared to the class I group (p-value = 0.008), without significant differences between other groups. There was no significant difference between vertical pattern groups in any of the tongue variables including TGL, TGH, mandibular length, and tongue position (p-value > 0.05).

Conclusion: The TGL was greater in class II patients, and the TGH was greater in class III patients. Also, class II patients had higher tongue posture compared to class I and III groups. Furthermore, vertical pattern had no significant influence on tongue position and dimension.

Introduction: Edentulism impairs mastication and dietary choices in older adults, often leading to malnutrition and associated health risks. Despite being a routine practice, the impact of prosthodontic rehabilitation on systemic and nutritional health outcomes is yet unknown.

Objective: To systematically review the effects of prosthodontic rehabilitation on nutritional and general health outcomes in elderly edentulous individuals and compare outcomes across prosthetic modalities.

Methods: A systematic review was conducted per PRISMA 2020 and PROSPERO registration (CRD420251147518) across PubMed, MEDLINE, Cochrane CENTRAL, and Scopus. Eligible studies included randomized clinical trials (RCTs) and clinical and observational studies assessing prosthodontic rehabilitation in adults ≥ 60 years of age that reported nutritional and general health outcomes. The risk of bias was assessed via the risk of bias 2 (RoB 2) for RCTs and the Newcastle-Ottawa Scale (NOS) for observational studies. Narrative synthesis was undertaken as the included studies differed substantially in their designs, interventions, and outcome measures.

Results: Fifteen studies (six RCTs and nine observational) were included. Masticatory function and quality of life related to oral health were consistently enhanced by prosthodontic rehabilitation. When denture provision was coupled with dietary advice, nutritional status improved. Bite power, mastication, and meal variety were all enhanced by implant-supported and single-implant overdentures; however, biochemical marker alterations were not consistent. Data pertaining to systemic outcomes are scarce (frailty, morbidity, and mortality).

Conclusion: Prosthodontic rehabilitation in elderly individuals improves chewing and quality of life, with modest but consistent benefits for nutritional outcomes. Stronger effects occur when combined with dietary counseling. Evidence for systemic outcomes remains limited. Future multicenter RCTs with longer follow-up periods and standardized nutritional endpoints are warranted.

Objectives: To develop a deep learning model to automatically identify palatal landmarks on three-dimensional (3D) digital maxillary dental casts, and to evaluate model performance.

Materials and methods: Twelve palatal landmarks were manually annotated on each 3D digital maxillary dental cast from 377 individuals in the permanent dentition stage. Manually annotated landmarks were used as ground truth to develop and to evaluate a deep learning model for automatic landmark detection. A two-stage PointNet++ architecture was employed, where coarse landmark predictions were first generated, followed by localized refinement for improved precision. The model accuracy was evaluated by measuring the linear discrepancy between the final predicted and the ground-truth landmark positions.

Results: A PointNet++-based hierarchical deep learning model, designed to extract both local and global features from point clouds, was developed. The model demonstrated a mean landmark detection error of 0.55 mm (SD ± 0.49) between predicted and ground-truth positions across 12 landmarks. The model also exhibited high predictive performance, correctly predicting 90% of landmarks within 1 mm and 98% within 2 mm of the ground truth.

Conclusions: A deep learning model was developed for automated identification of 12 palatal landmarks on 3D maxillary dental casts, which demonstrated high performance. Our model will enable more efficient morphological assessment of the palate by substantially reducing the time for manual annotation in clinical and research settings.

Objective: To evaluate the effect of hyaluronic acid (HA) lip augmentation on anterior tooth exposure and smile-line characteristics using three-dimensional (3D) facial scanning technology.

Materials and methods: Twenty-five female participants were enrolled. All injections were performed by a single experienced clinician following a standardized protocol, with a total of 1.0 mL of HA filler administered to the lips. 3D facial scans were obtained before treatment, immediately after injection, and at a 4-week follow-up. Maxillary left central incisor and canine exposure during smiling, as well as upper lip volume, were measured at each timepoint using dedicated software.

Results: The mean participant age was 26.2 years, and the mean follow-up period was 28.8 days. At follow-up, maxillary central incisor and canine exposure decreased by 0.1 mm compared to pre-treatment values (p  < 0.001). Upper lip volume increased by 0.79 mm³ at follow-up (p  < 0.001). An inverse correlation was observed between lip volume and central incisor exposure, indicating reduced tooth display with increased lip volume. No significant correlation was found between lip volume and canine exposure or between central incisor and canine exposure.

Conclusion: HA lip augmentation was associated with small but statistically significant changes in anterior tooth exposure during smiling. These findings highlight the influence of perioral soft tissue on smile-related dental parameters and underscore the importance of considering lip volume when planning esthetic dental and restorative treatments.

Statement of problem: The use of endocrowns as retainers for fixed partial dentures (FPD) may be considered questionable.

Purpose: This study aimed to compare stress distribution in FPD with an endocrown abutment made of two ceramic materials and different residual tooth structures.

Materials and methods: Models with a missing mandibular right first premolar and an endodontically treated second premolar with two different residual tooth wall height (RWH) of 4.5 and 3 mm were designed in CAD software. These models received two types of FPD made of lithium disilicate and zirconia ceramics and were subjected to occlusal and buccal force conditions. Finally, the von Mises stress distribution was assessed using ANSYS software.

Results: Comparison of stress distribution revealed that the model with 4.5 mm of RWH experienced a lower maximum von Mises stress than the model with 3 mm of RWH. Irrespective of load points, under both occlusal and buccal forces, the connector region is the area of greatest stress concentration. The results indicated that in all scenarios, the maximum von Mises stress in zirconia FPD was more than in lithium disilicate FPDs.

Conclusion: Increasing the extent of tooth preparation and structural damage will lead to higher von Mises stress. The highest maximum von Mises stresses were generated in the zirconia models and buccal load conditions. Both materials and designs were acceptable and could be used as FPDs with an endocrown as a retainer.

Clinical implications: The use of endocrowns as retainers for FPD can be considered as an alternative in certain cases, offering a balance between conservation of tooth structure and mechanical stability.

Purpose of the study: To compare the shear bond strengths (SBSs) of different provisional crown materials with various surface treatments when relined with autopolymerizing polymethyl methacrylate (PMMA).

Materials and methods: Part 1: Seventy-five specimens were divided into five groups: PMAC (autopolymerizing PMMA), PMAM (CAD/CAM system PMMA), PMAD (3D-printed PMMA), PLAI (injectable polylactic acid [PLA]), and PLAD (3D-printed PLA). All specimens were surface-treated by sandblasting followed by 180 s of MMA application, then relined with autopolymerizing PMMA. Part 2: Forty-five PLAD specimens were divided into three groups: PLAD (control), PLAD MC (methylene chloride treatment), and PLAD AT (acetone treatment), then relined with autopolymerizing PMMA. All samples underwent thermocycling before being evaluated for SBS with a universal testing machine (Shimadzu, Japan). Statistical analysis was performed using one-way ANOVA and Tukey's HSD at a significance level of p ≤ 0.05. Failure modes were examined using a stereomicroscope, and surface morphology was evaluated by scanning electron microscopy (SEM).

Result: In Part 1, the mean SBS values in MPa were: PMAC (26.85 ± 1.31), PMAM (22.92 ± 1.20), PMAD (13.98 ± 1.20), PLAI (10.19 ± 1.59), and PLAD (8.44 ± 1.14). Significant differences were found between all groups (p ≤ 0.05). In Part 2, the mean SBS values in MPa were: PLAD (8.44 ± 1.14), PLAD MC (8.35 ± 0.84), and PLAD AT (7.83 ± 1.13). No significant differences were found between the three groups (p  > 0.05). PMAC, PMAM, and PMAD exhibited mixed failure modes in 87.5%, 80%, and 73.3% at the fractured surfaces of the specimens, respectively. In contrast, PLAD and PLAI displayed 100% adhesive failure. PLAD, PLAD MC, and PLAD AT also showed 100% adhesive failure at fractured surfaces.

Conclusion: The PMAC group achieved the highest SBS among all tested materials. Surface treatment of PLAD with methylene chloride or acetone did not significantly improve SBS compared to the untreated control.

This study aimed to evaluate the fracture resistance of teeth with simulated internal root resorption cavities filled with calcium silicate-based cements (CSCs). Seventy-two extracted central incisor teeth had their crowns removed to standardize the root length to 14 mm. The teeth were randomized into six groups (n = 12 each), including a positive control (with no simulated resorption cavities) and negative control (with no filling) group. To simulate internal root resorption cavities, cavities were made along the 6 mm section using a number 10 round bur on groups. In four groups, artificially created resorption areas were filled with ProRoot MTA, Biodentine, NeoMTA 2, and BioMTA+. The specimens were subjected to fracture resistance testing using a universal testing machine (UTC). Compressive 135° angle loading was applied to the roots at a rate of 1 mm/min. The fracture resistance was recorded in Newtons and statistically analyzed using a one-way analysis of variance (Welch's test) and Tamhane's T2 test. The fracture resistance was significantly higher in the Biodentine group than in the negative control group. Therefore, the use of Biodentine in internal root resorption cavities may, to some extent, contribute to preserving or supporting the tooth structure.