Alveolar Bone Morphotype in Orthodontic Patients

Orthodontic treatments have been described as a risk factor for the development of gingival recessions. This descriptive and cross-sectional study was performed to evaluate the alveolar bone morphotype of the upper and lower anterior of 33 orthodontic treatment of candidate patients. The images were obtained from a high-resolution cone beam computerised tomography. Then, the thickness of the alveolar bone plate of teeth was measured in six levels, recording the presence of dehiscences and fenestrations. A total of 2,334 sites were evaluated. The average thickness of the maxillary alveolar bone at the buccal surface was 0.70, 0.62 and 1.43 mm at the cervical, middle and apical levels, respectively, while in the mandibular teeth it was 0.53, 0.50 and 2.96 mm. At the palatal and lingual surfaces, the bone was thicker than the buccal except at the apical level of the mandible. Most of the examined sites were measured less than 1 mm (n = 1,235, 52.9%), associated with high prevalence of bone dehiscences (57.6%) and fenestrations (33.3%), particularly in skeletal Class III patients. The observed bone morphotype involved a high vulnerability to bone resorption, and the subsequent gingival recession occurrence, face to orthodontic movements.

Deep semi-supervised learning for automatic segmentation of inferior alveolar nerve using a convolutional neural network

Background The inferior alveolar nerve (IAN) innervates and regulates the sensation of the mandibular teeth and lower lip. The position of the IAN should be monitored prior to surgery. Therefore, a study using artificial intelligence (AI) was planned to image and track the position of the IAN automatically for a quicker and safer surgery. Methods A total of 138 cone-beam computed tomography datasets (Internal: 98, External: 40) collected from multiple centers (three hospitals) were used in the study. A customized 3D nnU-Net was used for image segmentation. Active learning, which consists of three steps, was carried out in iterations for 83 datasets with cumulative additions after each step. Subsequently, the accuracy of the model for IAN segmentation was evaluated using the 50 datasets. The accuracy by deriving the dice similarity coefficient (DSC) value and the segmentation time for each learning step were compared. In addition, visual scoring was considered to comparatively evaluate the manual and automatic segmentation. Results After learning, the DSC gradually increased to 0.48 ± 0.11 to 0.50 ± 0.11, and 0.58 ± 0.08. The DSC for the external dataset was 0.49 ± 0.12. The times required for segmentation were 124.8, 143.4, and 86.4 s, showing a large decrease at the final stage. In visual scoring, the accuracy of manual segmentation was found to be higher than that of automatic segmentation. Conclusions The deep active learning framework can serve as a fast, accurate, and robust clinical tool for demarcating IAN location.

Univariate and multivariate sex dimorphism in the diverse age group of the South Indian dentition using the polyvinyl siloxane elastomeric impression material

Background In the South Indian population, an odontometric analysis was performed with the older age group (18 to 60 years) and using the dimensionally stable polyvinyl siloxane elastomeric impression material (PVS) that can create minute detail replicas of tooth structure. Both measurements of buccolingual and mesiodistal dimensions of all permanent teeth (except third molars) were taken with a digital vernier calliper on 400 dental models as a reference sample and 80 dental models as a test sample, with the data from the reference samples subjected to an independent samples t test and stepwise logistic regression analysis. Results Independent samples t test divulged that canines were the most sexually dimorphic teeth followed by buccolingual dimensions of central and lateral incisors. All tooth variables were found greater in males, i.e. 56/56 (100%), whereas stepwise logistic regression analysis formula disclosed that the prediction accuracy in the age group of 18 to 39 years was 91%, 85% and 73% using the teeth from both the jaws, maxillary teeth and mandibular teeth respectively; similarly, in the age group of 40 to 60 years, it was 85%, 84% and 83% using teeth from both jaws, maxillary teeth and mandibular teeth respectively; finally, in the overall age group of 18 to 60 years, it was 83% and 75% using teeth from both jaws, maxillary teeth and mandibular teeth respectively. The mean percentage of sex dimorphism was found high in South Indian dentition compared with other populations. Conclusions Nonetheless, the accuracy of the results obtained can be considered moderate to high, and sexing can be achieved using regression formulas for each age group, which reflects demographic diversity.

Ultrastructural Variations of Antennae and Labia Are Associated with Feeding Habit Shifts in Stink Bugs (Heteroptera: Pentatomidae)

The family Pentatomidae (stink bugs) is one of the largest groups in Heteroptera, containing many important pests and natural enemies. They exhibit highly diversified feeding habits and related structural modifications, but the key morphological characteristics associated with feeding habit radiation remain unclear. In the current study, we address this question by analyzing morphological variations of feeding related organs. We compare the ultrastructures of antennae and mouthparts across the chosen 17 species in Pentatomidae, representing both plant feeders and predators from four subfamilies. A strong association between ultrastructural adaptation and feeding habit transition has been revealed. The long, sharp, and hook-like mandibular teeth and maxillary barbs are exclusively present in predatory Pentatomidae, suggesting their tight association with the shift of feeding habit from phytophagy to predation. Significant differences between phytophagous and predatory species are also found in antennal and labial sensilla types and arrangements, implying their important function in food selection. Our data identify a series of key morphological structures associated with feeding habit variations among stink bugs, which will facilitate future studies on adaptive evolution of feeding habits, utilization, and population control of economic species in Pentatomidae as well as in other heteropteran lineages.

The Impact of Orthodontic Treatment on Pre-Existing Gingival Recessions: A Retrospective Study

(1) Background: This retrospective study aimed to examine the change of gingival recessions (GR) before and after orthodontic treatment (OT). (2) Methods: Patients who had at least one GR on the vestibular surface of maxillary/mandibular teeth mesial to first molars were included. GR was measured on good quality plaster models before and after OT. (3) Results: Significant improvement of mean GR at patient level was found between T0 and T1 (0.45 mm, 95% CI: 0.28, 0.62) (p < 0.001). In 51.4% of patients GRs became better, in 37.8% GRs did not change. and in 10.8% GRs became worse. At tooth level the mean GR improvement was 0.54 mm (CI: 0.42, 0.65; median 0.55 mm Q1; Q3: 0.12, 0.96) (p < 0.001). GR improved in 67 teeth (58.7%), did not change in 41 (36.0%), and worsened in 6 (5.3%). Full healing was observed in 15 teeth. A reduced GR improvement was found in cases with pre-treatment open bite (OR 3.89; CI: 1.35, 11.16; p = 0.008) and dental Class III patients (OR 2.6; CI: 1.11, 6.0; p = 0.026). (4) Conclusion: There was an improvement of GR after OT in more than half of the patients. Class III malocclusion and reduced pre-treatment overbite had a negative impact on GR improvement.

Efficacy of 4% articaine vs 2% lidocaine in mandibular and maxillary block and infiltration anaesthesia in patients with irreversible pulpitis: a systematic review and meta-analysis

Objective The goal of this systematic review and meta-analysis is to determine the performance of 4% Articaine vs. 2% Lidocaine for mandibular and maxillary block and infiltration anaesthesia in patients with irreversible pulpitis (IP). Methods PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, Google Scholar, and Open Gray were used to conduct a thorough literature search. A manual search of the reference lists of the publications found was also carried out. Two reviewers critically evaluated the papers for inclusion and exclusion criteria, and data extraction was done on the selected publications. The Cochrane Collaboration Tool and the Minors checklist were used to assess the quality of the selected studies for randomised controlled trials (RCTs) and non-randomised studies, respectively. The RevMan software was used to perform a meta-analysis of the pooled data and subgroups according to the technique of anaesthetic solution delivery, as well as a sensitivity analysis (P < 0.05). Results A total of twenty-six papers were included in the qualitative synthesis, with twenty-two of them being included in the meta-analysis. There were fifteen studies with a low potential for bias, three with a moderate potential for bias, and seven with a high potential for bias. The combined results of the 19 trials in the tooth level unit revealed that 4% articaine had a success rate 1.37 times greater than 2% lidocaine for mandibular teeth (RR, 1.37; 95% CI [1.17–1.62]; P = 0.0002). For the maxillary buccal infiltration method, the combined results from the three trials revealed that 4% articaine resulted in a success rate 1.06 times greater than 2% lidocaine (RR, 1.06; 95% CI [0.95–1.2]; P = 0.3). Excluding subgroups with a single study in sensitivity analysis for mandibular teeth revealed a substantial improvement in the success rate of the articaine group in treating IP when compared to the lidocaine group. Conclusion The findings of this meta-analysis back up the claim that articaine is more effective than lidocaine in providing anaesthesia in patients with IP. PROSPERO Registration No.: CRD42020204606 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020204606).

An assessment of root stage of canine and premolar teeth at alveolar eruption

Objective: The primary aim was to evaluate the degree of root development of permanent canines at the time of alveolar eruption. We also aimed to assess whether differences in the degree of root development at alveolar eruption exist between permanent canines and premolars and between maxilla and mandible. Design: A cross-sectional study. Setting: Barts and The London School of Medicine and Dentistry, Queen Mary University of London. Participants: Two hundred dental panoramic radiographs taken as part of routine dental care. Methods: Radiographs were assessed for canine and premolar root development stage and eruption level with calibration and repeat measurements undertaken. Results: Two hundred and sixty teeth were identified as being at the level of alveolar eruption. The majority of maxillary canines reached alveolar eruption when root formation was complete. Most premolars and mandibular canines reached alveolar eruption when roots were three-quarters developed. At alveolar eruption, canines were statistically more mature than premolars (p<0.001) and maxillary teeth were more mature than mandibular teeth (p<0.05). Conclusions: Root development appears to be particularly advanced for maxillary permanent canines, being essentially root-complete at alveolar eruption, while premolars and mandibular permanent canines appear to have three-quarters root development at this stage. This information may be used to inform whether and when to extract primary teeth for orthodontic reasons.