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Purpose: The aim of this retrospective study was to assess the short- to mid-term restorative and periodontal outcome of deep margin elevation (DME) performed using resin composite. Materials and Methods: Twenty-eight teeth treated with DME and indirect adhesive restorations were followed-up for a mean of 25.4 months (minimum: 12 months). Clinical and radiographic examination assessed the adaptation of the DME material and indirect restorations, presence of recurrent caries or discoloration, periodontal health at DME and non-DME sites, and periapical health. Results: The overall success rate was 96.6%. One tooth showed signs and symptoms of apical pathology after 34 months following DME. No caries, discoloration, or periodontal pockets were detected in any of the treated teeth. DME had no detrimental effect on the gingival/periodontal health or plaque accumulation. There was no correlation between the distance from the DME material to the marginal bone level and pocket depth, gingival inflammation, and plaque accumulation (p > 0.05). Conclusion: Deep margin elevation might be considered a safe procedure for teeth with deep subgingival proximal caries in the short- and mid-term. [ABSTRACT FROM AUTHOR]

Detection and teeth segmentation from X-rays, aiding healthcare professionals in accurately determining the shape and growth trends of teeth. However, small dataset sizes due to patient privacy, high noise, and blurred boundaries between periodontal tissue and teeth pose challenges to the models' transportability and generalizability, making them prone to overfitting. To address these issues, we propose a novel model, named Grouped Attention and Cross-Layer Fusion Network (GCNet). GCNet effectively handles numerous noise points and significant individual differences in the data, achieving stable and precise segmentation on small-scale datasets. The model comprises two core modules: Grouped Global Attention (GGA) modules and Cross-Layer Fusion (CLF) modules. The GGA modules capture and group texture and contour features, while the CLF modules combine these features with deep semantic information to improve prediction. Experimental results on the Children's Dental Panoramic Radiographs dataset show that our model outperformed existing models such as GT-U-Net and Teeth U-Net, with a Dice coefficient of 0.9338, sensitivity of 0.9426, and specificity of 0.9821. The GCNet model also demonstrates clearer segmentation boundaries compared to other models. [ABSTRACT FROM AUTHOR]

Different types of scanners are gradually used to produce digital dental casts in the current dental practice. This study tested the accuracy of the three desktop scanners and two intraoral scanners and evaluated whether the desktop scanners had higher precision than the intraoral scanners. This study used the three desktop and two intraoral scanners to scan a standard dental cast 5 times. The 5 digital casts produced by the same scanner were compared each other to study the precision errors of each scanner. Moreover, 5 sets of the 5 digital casts produced by the 5 different scanners were compared each other to investigate the trueness errors among these 5 different scanners. This study showed a significant difference in the precision error of produced digital casts made by the 5 different scanners (P < 0.0001). The two intraoral scanners had significantly higher precision errors of produced digital casts than the three desktop scanners. However, there were no significant differences in the precision errors among the three desktop scanners and between the two intraoral scanners. The results of the whole cast or particular tooth surface trueness analyses demonstrated that the trueness errors were concentrated at the molar regions of produced digital casts when comparisons were performed between the intraoral and desktop scanners. We conclude that the desktop scanners can achieve a better precision than the intraoral scanners. When the intraoral scanner is used, the dentist should notice the possible model errors at the molar regions. [ABSTRACT FROM AUTHOR]

Orthodontic movement is often necessary for periodontally compromised patients to enhance esthetics, function, and long-term occlusal stability. However, the impact of orthodontic treatment immediately following the regeneration of intrabony defects on periodontal healing remains a topic of debate. The objective of this long-term case series study was to test the hypothesis that orthodontic treatment performed immediately after regenerative procedures for periodontal intrabony defects did not adversely affect periodontal healing. This case series study involved nine periodontally compromised subjects with a total of 17 intra-bony defects. Orthodontic brackets were applied immediately before surgery. Flaps were raised, and diseased roots were debrided. All intra-bony defects were filled with alloplastic bone grafts and covered with resorbable membranes, except for one defect treated with Emdogain. All patients initiated orthodontic treatment immediately after periodontal regenerative surgery. Clinical parameters, including probing depth, attachment level, and bone fill, were assessed at baseline and during final maintenance therapy. The mean follow-up duration was 12.8 years. None of the 17 surgically regenerated teeth were lost. The mean reduction in probing depth was 3.94 mm (95% confidence level, 3.19–4.68; P < 0.001), with a mean clinical attachment gain of 3.47 mm (95% confidence level, 2.90–4.03; P < 0.001). The mean radiographic bone fill was 4.89 mm (P < 0.001). Based on the findings of this long-term case study, it can be concluded that immediate orthodontic treatment does not adversely affect the maturation process of periodontal regeneration outcomes and can be maintained for more than ten years. [ABSTRACT FROM AUTHOR]

Prosthetic rehabilitation in multifaceted dental abnormality needs sequential planning to ensure adaptation of oral and associated musculature. Reduction of tooth structure before adaptation of oral and associated components may complicate the treatment modality if compliance of the musculature is poor. Hence, the fabrication of over-provisional in esthetic rehabilitation enables to assess of the success of the treatment plan preoperatively before invasive trials. A 55-year-old male with a diagnosis of Category I loss of vertical dimension, according to Turner and Missirlian classification, required full mouth rehabilitation. The case report depicts the preoperative management of full mouth rehabilitation with direct chair-side technique using over-provisional to analyze the esthetic and functional changes. Restoration of esthetics is a complex task that needs patient satisfaction to achieve success. Over-provisional is a simplified method of establishing esthetics and functional rehabilitation. Esthetic and functional rehabilitation of an individual can be an easy transition when preoperative evaluation of the final prosthesis design is visually created intraorally. [ABSTRACT FROM AUTHOR]

The remarkable evolution of teeth morphological complexity represents a giant leap for vertebrate. Despite its importance in life history, the understanding of spatiotemporal organization of teeth remains rudimentary. Herein, a high‐resolution genome‐wide molecular patterning of lineage allocation and cellular organization in tooth morphogenesis is described, constructed by integrating spatial transcriptome and single‐cell RNA sequencing. Twelve spatial compartments and seventeen heterogeneous cell clusters linked to tooth morphogenic milestones are identified. Eighty‐eight percent of total lineage species has already appeared in the initial tooth bud rather than the generally considered sequential emergence. A previously unrecognized sprouting‐like patterning mode of the dental papilla is discovered, that the inner compartment can break through the outer shell compartment to build up the final papilla cusp. Meanwhile, the continuum differentiation hierarchies of enamel knots in time and space are revealed. Furthermore, the regulatory network directing tooth morphogenesis is established, whereby a series of mechanotransduction signals are spatiotemporally involved beyond the well‐established classical odontogenesis signals. Finally, genes underlying tooth dysplasia are successfully tracked to highly specific time points and cell types. The results raise the idea that tooth morphogenesis is orchestrated by mechanical niches combined with biochemical signaling. [ABSTRACT FROM AUTHOR]

Background: This study aimed to evaluate the accuracy of laser fluorescence (LF) readings in detection of caries removal by various techniques (CRTs). Methods: A hundred and eighty extracted human molar teeth included in the study which were scored 3, 4, and 5 according to ICDAS. Each score group was randomly assigned to 4 subgroups according to CRT including ceramic bur (Group A), carbide bur (Group B), carbide bur with alumina abrasion (Group C), and carbide bur with bioactive glass (BAG) abrasion (Group D) (n = 15 for each group). A LF device (DIAGNOdent Pen, Kavo) was used to determine remaining caries. Histological sections of the teeth were examined under a dental operating microscope for validation. The data were analyzed using Fisher Freeman Halton, Fisher's Exact, Pearson Chi-Square, Bonferroni Adjusted Z tests, ROC analysis, Kappa statistic and Binary Logistic Regression(p < 0.05). Results: Histological examination revealed no significant differences among the CRTs and ICDAS scores (p > 0.05 for each). However, a significant difference was found between histological assessment and LF in ICDAS 5 score, specifically between Group B and Group D (p = 0.022), regarding caries presence. LF readings demonstrated over 0.9 area under curve (AUC) value regardless of CRT, except for ICDAS-4 score, and Group D in ICDAS-5 score. Overall, the AUC of LF was found to be 0.880 for the 38 cut-off point (p < 0.001), indicating a high level of accuracy. The univariate and multiple models showed the tested CRTs had no effect on the caries presence (p > 0.050). Conclusions: The CRTs examined in this study demonstrated similar efficacy in terms of caries removal. However, the application of bioactive glass on caries-affected dentin may lead to overestimations in the LF readings. Additionally, LF on the cavity floor may not be clinically suitable for teeth with ICDAS 4 scores. Clinical relevance: The clinical determination of caries removal endpoint is based on a multifactorial decision. However, when selective removal of soft dentin is performed, especially with bioactive glass abrasion in deep caries lesions, higher cut-off points might be determined in laser fluorescence readings to decide further operative intervention. [ABSTRACT FROM AUTHOR]

Background: Clear aligner treatment (CAT) has emerged as an effective alternative to conventional multibracket systems in orthodontics. The trimline design and extension of aligners may significantly influence their biomechanical performance and tooth movement efficacy. Aim: To systematically review the biomechanical effects of different aligner trimline designs and extensions on orthodontic tooth movement. Methods: A systematic search was conducted across PubMed, Scopus, Embase, ProQuest Dissertations & Theses Global, and Google Scholar for studies published between January 2000 and August 2024. The review included any types of empirical research focusing on the influence of trimline of orthodontic aligners on tooth movement efficacy conducted between January 2000 and August 2024. The Risk of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool was used for quality assessment. Results: Twelve studies met the inclusion criteria, all assessed as having low to moderate risk of bias. Aligner trimline design significantly influenced orthodontic tooth movement efficacy through two primary mechanisms: enhanced force delivery and increased aligner retention. Aligners with straight and extended margins generally exerted higher forces and moments compared to scalloped or shorter designs. This resulted in greater tooth displacement for certain movements, particularly intrusion, translation, tipping, and root torquing. Extended trimlines also demonstrated superior retention. However, the effects varied depending on the type of tooth movement. Conclusion: Aligner trimline designs and extensions can significantly influence biomechanical performance and tooth movement efficacy in CAT. Straight extended trimlines generally demonstrate superior force delivery and retention, leading to more predictable clinical outcomes. This could reduce the need for revisions, thereby decreasing overall treatment time and increasing patient satisfaction. However, further research is needed to investigate the interactions between aligner trimline designs and other factors to develop evidence-based guidelines for their optimal combination in various clinical scenarios. [ABSTRACT FROM AUTHOR]

Background: Achieving ideal anchorage is crucial in orthodontics for controlled tooth movement. Miniscrews (MSs) have improved skeletal anchorage, but freehand placement poses risks like root damage and limited precision. Guided techniques, including radiographic guides and computer-assisted methods (static [sCAS] and dynamic [dCAS]), were developed to enhance accuracy and safety. Objective: This systematic review and meta-analysis aimed to evaluate the safety and accuracy of MS placement using different guidance approaches. Materials: A systematic search up to March 2024 identified studies on guided MS insertion, assessing safety (root contact/damage) and accuracy (angular, coronal, and apical deviations) of guided vs. freehand placement. Two reviewers assessed the risk of bias and study quality using RoB 2 for RCTs, NOS for cohort studies, and an adapted tool for pre-clinical studies. Random-effects meta-analysis was performed for studies with common parameters, and safety outcomes were pooled using logit-transformed proportions. Heterogeneity was evaluated with I² and χ² tests. Results: Eleven studies (652 MSs) were included, though no dCAS studies were analyzed. The only RCT had "some concerns" regarding risk of bias, cohort studies ranged from medium to low quality, and most pre-clinical studies had high bias risk. sCAS significantly reduced root damage compared to freehand methods (OR = 0.11; 95% CI: 0.04–0.36; p < 0.001; I² = 1%) and reduced angular and linear deviations. Due to heterogeneity, no quantitative synthesis of accuracy outcomes was performed. Conclusions: sCAS improves the safety and accuracy of MS insertion compared to freehand and radiographic guide methods. These results highlight the clinical benefits of sCAS in orthodontics. Future studies should refine protocols and explore dCAS for further accuracy improvements. [ABSTRACT FROM AUTHOR]

Background/Objectives: Impacted teeth are a common phenomenon, in both young and adult populations, as extensively documented in the literature. This study aims to systematically assess the global prevalence of impacted third molars and to analyze their demographic predictors. Methods: The present review adheres to PRISMA guidelines and includes studies published until December 2023. Three databases (MEDLINE, LILACS, Cochrane) were searched, and studies reporting prevalence rates and demographic predictors of impacted third molars were selected for analysis. A meta-analysis was conducted using a random-effects model to calculate pooled prevalence and assess demographic variations. Results: This review yielded 98 studies involving 183,828 subjects. The pooled prevalence of impacted third molars was 36.9% [95% CI: 33.1–40.7%] per subject and 46.4% [95% CI: 36.7–56.1%] per tooth, with the highest rates in Asia (43.1% [95% CI: 34.6–51.7%]) and the lowest in Europe (24.5% [95% CI: 16.1–33.9%]). An odds ratio of 1.173 [95% CI: 1.021–1.347%] indicated a slightly higher likelihood of third molar impaction among women compared to men, and mandibular third molar impaction was more frequent than maxillary impaction. The meta-regression indicated insufficient consistency for the geographic area to be considered a source of heterogeneity in the prevalence of impacted third molars. Conclusions: The present meta-analysis highlights the substantial prevalence of impacted third molars worldwide and underscores the influence of demographic predictors. These findings may inform region-specific clinical guidelines and preventive approaches for managing impacted third molars. [ABSTRACT FROM AUTHOR]

This paper investigates tool deflection and its compensation in Drill Thread Milling (DTM), a novel method for internal thread fabrication. The study proposes a heuristic model that integrates lateral force estimation and soft collision techniques to counteract tool deflection. The model's effectiveness was validated through extensive experiments across various cutting conditions, workpiece materials, and thread sizes. Results indicate that feed per tooth significantly affects tool deflection more than cutting speed, and low machinability materials exhibit greater deflection. Larger thread sizes also lead to increased deflection due to higher cutting forces. The proposed compensation method effectively reduces deflection, ensuring the resulting threads meet specified standards. This study provides valuable insights for optimizing DTM processes, improving precision, and enhancing manufacturing efficiency. [ABSTRACT FROM AUTHOR]

This study utilised a prototype system which consisted of a person-specific 3D printed jaw tracking harness interfacing with the maxillary and mandibular teeth and custom jaw tracking software implemented on a smartphone. The prototype achieved acceptable results. The prototype demonstrated a static position accuracy of less than 1 mm and 5°. It successfully tracked 30 cycles of a protrusive excursion, left lateral excursion, and 40 mm of jaw opening on a semi-adjustable articulator. The standard error of the tracking accuracy was reported as 0.1377 mm, 0.0449 mm, and 0.9196 mm, with corresponding ${r^2}$ r 2 values of 0.98, 1.00, and 1.00, respectively. Finally, occlusal contacts of left, right, and protrusive excursions were tracked with the prototype system and their trajectories were used to demonstrate kinematic modelling (no occlusal forces) with a biomechanical simulation tool. [ABSTRACT FROM AUTHOR]

The capacity to produce multiple generations of teeth allows for changes in dentition morphology throughout an animal's life. This adaptation can accommodate different dietary strategies at different life stages, most notably between juvenile and adult stages. Common changes between tooth generations include variations in tooth number and morphological parameters. In this study, we compare the dentition morphology of juvenile and adult specimens from four species of Cuban false chameleons in the genus Anolis (Chamaeleolis group) within the Iguania clade of squamate reptiles. Unlike most anole lizards, which are primarily insectivorous or saurivorous, these species are specialised feeders on shelled snails and possess distinctive broad molariform teeth at the back of their jaws. The exact dietary preferences of these species remain unclear. Our findings reveal that juveniles differ from adults by the presence of tricuspid teeth at the back of the jaw and that the examined species exhibit differences in dentition, such as tooth number, shape, arrangement of cusps and crests, presence of molariform teeth, and internal tooth structure. Based on these observations, we discuss how interspecific and age-related changes in dentition may reflect differences in diet. [ABSTRACT FROM AUTHOR]

Understanding the growth patterns and developmental trajectories of teeth during early life stages provides valuable insights into the ontogeny of individuals, particularly in archaeological populations where such information is scarce. This study focuses on first deciduous molars, specifically investigating crown formation times and daily secretion rates, through histological analysis. A total of 34 teeth from the Early Medieval necropolises of Casalmoro and Guidizzolo (Mantua, Lombardy, northern Italy) were analysed assessing growth parameters and identifying possible differences between sites and between sexes, which are determined through proteomic analysis. Furthermore, a robust linear regression model relating prism length and secretion time was built to estimate growth rates also in teeth in which the finest incremental markings are not visible. The daily secretion rates (DSR) in inner enamel showed a high homogeneity between dental arches, sexes and the two sites. Values fall within the known range reported in the literature for the same tooth class in archaeological populations. However, a difference in DSR was observed when compared with modern sample published values. Crown formation times and age at crown completion differ between dental arches, with maxillary first molars initiating their matrix apposition earlier than mandibular molars as formerly reported. However, no significant differences were highlighted in association with sex. This study expands our understanding of the growth and development of the first deciduous molars in a medieval population, providing valuable insights into growth trajectories specific to the dental arch. These findings highlight the need for extensive investigations using similar methodologies to attain more accurate and comprehensive information about the developmental patterns of first deciduous molars. Additionally, proteomic analysis improves the capability to conduct sex-specific histological assessments of immature individuals, thanks to this method's application in determining their sex. [ABSTRACT FROM AUTHOR]

ABSTRACT: This case report discusses a case of a maxillary central incisor with pulp canal obliteration (PCO), managed by guided endodontic access. A preoperative periapical (PA) radiograph and cone beam computed tomography (CBCT) displayed an incidental finding of a periapical radiolucency (PARL), indicating a PA lesion of endodontic origin on tooth #11. An intraoral three-dimensional (3D) scan was obtained, and its data and CBCT images were processed using planning software. A digital model of the guide was designed and 3D printed. The guide was placed on the tooth surface, and the tooth was accessed until the desired length was reached and the canal was located. Non-surgical root canal treatment was conducted, and the canal was obturated with gutta-percha and bioceramic sealer. A final restoration was placed with flowable composite along with the placement of a full ceramic crown. A 1-year recall showed complete healing of the apical area. [ABSTRACT FROM AUTHOR]

ABSTRACT: Aim: This study aimed to explore the relationships between bizygomatic width, inter-orbital distance, and the central incisor width (CIW). Materials and Methods: A total of 80 cone beam computed tomography (CBCT) scans were analyzed. The measurements taken included bizygomatic width and inter-orbital distance. A bivariate correlation was performed to evaluate the relationships between CIW and craniofacial measurements. Independent samples t -tests were used to compare these measurements between genders. Results: Mean values for CIW and bizygomatic width were significantly higher in males than females (P < 0.05). The bivariate analysis revealed significant, positive, moderate correlations between CIW and bizygomatic width (r = 0.401, P < 0.01), but not inter-orbital distance (P > 0.05). Conclusion: This study found that while bizygomatic width is moderately correlated with CIW, inter-orbital distance is not. Additionally, significant gender differences exist regarding bizygomatic width and CIW, with males exhibiting larger dimensions. [ABSTRACT FROM AUTHOR]

ABSTRACT: Introduction: Discoloration of teeth is one of the undesirable consequences of silver diamine fluoride (SDF). Aims and Objectives: This study aimed to evaluate the scientific evidence regarding the effect of SDF on tooth discoloration filled with composite resin restoration in different periods. Materials and Methods: Forty-five extracted human premolar permanent teeth are obtained from periodontal therapy or orthodontic therapy. The teeth are divided into groups A, B, and C (n = 15) in which group A served as the control group and only received composite restoration. The other two groups received composite applications on one of two schedules (immediately after the SDF application vs. delayed by 4 weeks after the SDF application). Results: There was no statistical difference in color changes either with immediate or delayed composite application to treated teeth with SDF. Conclusion: Under laboratory conditions, delayed application of composite after SDF shows less discoloration than the immediate composite application. [ABSTRACT FROM AUTHOR]

ABSTRACT: Aim: In this in vitro study, the microleakage evaluation of repaired pit and fissure sealants with various surface treatments was compared. Study Design: The study included 120 extracted human third molars. The teeth were divided into two groups of 60 each. Group 1 was sealed with Clinpro™ unfilled sealant, while group 2 was sealed with Grandioseal nanofilled sealants. After curing, half of the polymerized sealant were removed. Both groups were divided further into two subgroups of 30 teeth each, with repair techniques using either Adper Easy One or Futura Bond. Three sections were obtained from each tooth resulting 6 surfaces per tooth to be examined and the sections of all four groups were scored for microleakage. Results: Conventional acid etching was found to be superior to self-etch adhesive technique. Conclusion: Microleakage was found to be greater with Grandio seal compared to Clinpro. [ABSTRACT FROM AUTHOR]

Background: Oral health is recognized as integral to general health and impaired dentition status may affect physical performance among older adults. This study evaluated the longitudinal association between clinical and self-reported oral health measures and physical performance (outcome) in Brazilian older adults. Methods: This was a longitudinal study that used data from the second (year 2006), third (year 2010) and fourth (year 2015) waves of the Health Well-being and Aging Study conducted in Brazil. Physical performance, evaluated using the Short Physical Performance Battery (SPPB), was the dependent variable. Independent variables of interest were the number of teeth, presence of periodontal pocket, use of dental prostheses, and poor perceived oral health. The association between oral health measures and physical function was analyzed using generalized estimating equations with an ordinal regression model. Results: In the total sample, every additional tooth was associated with a greater chance of achieving a higher score on the SPPB test. Individuals wearing dental prostheses had higher chances of having higher scores than those not wearing them. In the analyses for the dentate sample, the presence of a periodontal pocket was not associated with SPPB and the increase in the number of teeth increased the chance of achieving a higher score. Conclusion: A greater number of teeth, and using dentures, were associated with higher physical performance. Periodontal disease was not associated with the outcome. [ABSTRACT FROM AUTHOR]

Universal shade flowable composites have been introduced to mimic tooth structure with reduced color mismatch and reduced chair time and cost. However, the polymerization shrinkage of resin material may lead to sensitivity and restoration failure. The purpose of this study was to compare the polymerization shrinkage of recently introduced universal shade flowable resin-based composites using both wet and dry density methods. Using two measurement methods, ISO 17304 (wet method) and a gas displacement pycnometry system (dry method), the density of the unpolymerized and the polymerized RBCs were measured, and the polymerization shrinkage was calculated from the density difference. Scanning electron microscopy was used to visualize filler particles. The polymerization shrinkage showed significant differences between many materials. In particular, Bulk Base HARD II Medium Flow showed significantly lower polymerization shrinkage than all the other materials. Shrinkages measured by different methods were significantly different in all cases. The wet method measured a smaller shrinkage than the dry method in most cases, but the shrinkage measured for Gracefil LoFlow was larger with the wet method. Shrinkage between universal shade flowable resin-based composites significantly varied based on both material and measurement method. The polymerization shrinkage of resin-based composites is an important factor in biomimetic clinical dentistry, and work must be conducted to measure it accurately and with more standardization. [ABSTRACT FROM AUTHOR]

This is the first record of the biggest Metriorhynchidae, aff. Plesiosuchus sp. in France. The remains consist of a partial vertebral column consisting of 11 vertebrae and an ischium fragment. A new method is proposed to evaluate the individual's size, which is estimated at 6.5 m. This method, unlike previous approaches, is based only on vertebrae and yields results that are congruent with those based on cranial remains. The state of preservation has allowed us to test the animal's 'profile of locomotion' to better interpret how it moved. Concerning other metriorhynchids, the record of Dakosaurus in France based only on teeth must be reassessed, and the genus Torvoneustes, if valid, has to be distinguished from Plesiosuchus. [ABSTRACT FROM AUTHOR]

Dental panoramic X-ray imaging, due to its high cost-effectiveness and low radiation dose, has become a widely used diagnostic tool in dentistry. Accurate tooth segmentation is crucial for lesion analysis and treatment planning, helping dentists to quickly and precisely assess the condition of teeth. However, dental X-ray images often suffer from noise, low contrast, and overlapping anatomical structures, coupled with limited available datasets, leading traditional deep learning models to experience overfitting, which affects generalization ability. In addition, high-precision deep models typically require significant computational resources for inference, making deployment in real-world applications challenging. To address these challenges, this paper proposes a tooth segmentation method based on the pre-trained SAM2 model. We employ adapter modules to fine-tune the SAM2 model and introduce ScConv modules and gated attention mechanisms to enhance the model's semantic understanding and multi-scale feature extraction capabilities for medical images. In terms of efficiency, we utilize knowledge distillation, using the fine-tuned SAM2 model as the teacher model for distilling knowledge to a smaller model named LightUNet. Experimental results on the UFBA-UESC dataset show that, in terms of performance, our model significantly outperforms the traditional UNet model in multiple metrics such as IoU, effectively improving segmentation accuracy and model robustness, particularly with limited sample datasets. In terms of efficiency, LightUNet achieves comparable performance to UNet, but with only 1.6% of its parameters and 24.0% of the inference time, demonstrating its feasibility for deployment on edge devices. [ABSTRACT FROM AUTHOR]

Background: The growing body of knowledge on the human genome and its variants points towards the significance of genetic factors in oral health and disease. Since the dental curricula have historically prioritized clinically oriented subjects, this focus has resulted in insufficient coverage of genetics. To leverage this knowledge in patient care, dental education must equip students with an understanding of the principles of genetics. Method: We have established "Genetic Educators Network in Dentistry" (GEN-Dent) to identify common concerns regarding genetics in dental education and work for a greater emphasis on genetics in future dental programs to make sure that professionals in dentistry are well-prepared to navigate the complexities of the evolving "human genome era". Results: Here, GEN-Dent proposes specific learning goals for medical genetics in dentistry and provides supporting teaching material addressing each learning goal. The five life-like case studies exemplify different dental conditions and introduce important concepts of genetics, inspiring other educators. Conclusions: Opportunities in Scandinavian countries can be an advantage in increasing global awareness of the importance of genetics in dentistry. The integration of genetics into dental education not only aims to improve patient care but also seeks to inspire a new generation of basic scientists with clinical backgrounds in dentistry. We expect that using life-like patient cases will significantly motivate dental students when learning medical genetics. [ABSTRACT FROM AUTHOR]

The orthodontic management of patients with Class III malocclusion poses numerous treatment challenges. Various removable, fixed, orthopedic, and myofunctional appliances have been recommended for its correction. The Reverse Twin Block is a removable appliance which has been used for the early management of such cases. A 10‐year‐old female with no significant medical and family history presented with the chief complaint of forward placement of lower front teeth on biting. Extraoral examination revealed a mesoprosopic face, a prominent lower lip, and a shallow mentolabial sulcus. Facial profile was straight at rest and concave at maximum intercuspation. Intraoral examination revealed a Class III incisor relationship with premature contact between 21 and 31, causing a forward path of closure of the mandible. The patient had a reverse overjet of 2 mm, an overbite of 5 mm, and a bilateral Super‐class I molar relationship at maximum intercuspation. Lateral cephalogram analysis revealed a mild skeletal class III denture base (ANB = 0°, Wits = −4 mm) due to a prognathic mandible (SNB = 82°). The treatment objectives included elimination of the premature contact, establishment of a positive overjet, and improvement of the facial profile. A Reverse Twin Block appliance was planned and prescribed for full‐time wear for 8 months. At the end of treatment, the patient had a Class I incisor relationship, straight facial profile, Class I molar relationship on the left side, and Super‐class I molar relationship on the right side. The Reverse Twin Block is a simple and well‐tolerated appliance that can effectively correct developing Class III malocclusion in carefully selected cases. [ABSTRACT FROM AUTHOR]

Intentional replantation has been shown to be a viable treatment option for failed endodontic cases with long‐term success rates. [ABSTRACT FROM AUTHOR]

The study aimed to radiographically assess the characteristics of pulp stones (PS) and pulp canal obliteration (PCO) in teeth and examined their associations with various dental parameters such as caries, restorations, periodontal status, and age. This cross-sectional observational study was conducted at the Faculty of Dentistry, King Abdulaziz University between September 2022, and May 2023, involved 101 patients exhibiting 402 teeth with PS or PCO. Data were collected from periapical and bitewing radiographs, and analyzed by two calibrated dentists. Multiple dental parameters were assessed, including caries level, presence and level of restorations, periodontal condition, and age of the patient. The study population consisted of 62 females and 39 males, with an age range of 18–65 years. Inter- and intra-examiner reliability were high (Kappa = 0.88 and 0.98 respectively). PS were more commonly found in molars (81.2%), while PCO were presented in only 115 teeth (23%). Age significantly affected the type of calcification (p < 0.001), with PS more common in the 20–30 age group and PCO more common in individuals over 40. Presence of caries was significantly associated with the type of calcification (p = 0.013), but restoration was not. The majority of teeth with PS (76%) or PCO (93%) had healthy periodontium. Around 40% of teeth with PCO showed signs of periapical changes, a finding significantly different from those with PS (p < 0.001). Pulp calcifications were significantly associated with various dental parameters, including caries presence, age, and periodontal status. The findings provide crucial insights into the epidemiology and aetiology of pulp calcifications. [ABSTRACT FROM AUTHOR]

Aim: To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR. Methods: Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing). Results: The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy. Conclusions: There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases. [ABSTRACT FROM AUTHOR]

Low-angle straight tooth face gear transmission has significant advantages such as compact structure, small axial force, good shunt effect, and insensitivity to installation errors, demonstrating great superiority in the main reduction and torque distribution structure of helicopters. In this paper, the calculation of cutting force in the process of gear turning is studied, and the mathematical model of low-angle straight tooth face gear is established, and the numerical calculation and simulation analysis of cutting force are completed. On this basis, the gear machining test was completed on the gear machine, and the actual cutting force was collected, which verified the correctness of the cutting force calculation method and the feasibility of the cutting force optimization scheme, and provided a new solution for the cutting force calculation of the low-angle straight tooth face gear machining in industrial production. [ABSTRACT FROM AUTHOR]

In micro-milling process, the prediction of cutting forces is important for investigating the mechanism of material removal, optimizing the process parameters, and monitoring the machining process. To improve the modelling accuracy, this paper proposes a novel instantaneous uncut chip thickness (IUCT) model that considers the elastic recovery accumulation (ERA) in the micro-milling process. It thus includes the phenomenon of varying IUCT at the current tool tip due to the elastic recovery of the previous tool tip during tool rotation. When the IUCT is less than the minimum uncut thickness (MUCT), the height of the elastic recovery can be increased due to the effect of ERA, while the height keeps constant after IUCT reaches above MUCT. Three cases of ERA are presented by comparing the feed per tooth with both tool runout and MUCT. Finally, micro-milling experiments have been conducted to verify the proposed cutting force model. In comparing with the measured cutting forces, it is shown that the predicted cutting forces with the ERA considered exhibit a much better accuracy than that without the ERA considered. When the feed per tooth is at a small amplitude, the improvement of the cutting force prediction accuracy becomes even more significant. [ABSTRACT FROM AUTHOR]

Reducing the flow rate (q) of the emitter can increase the dripline laying length and reduce the engineering investment of the drip irrigation system; however, reducing q increases the risk of emitter clogging. In this study, based on the OPFN method (Optimal Latin Hypercube Experimental Design–Parametric Modeling of Emitter–Fluid Dynamics Simulation–NSGA-II Genetic Algorithm Optimization), we selected the structural parameters of channel tooth height (E), angle (A), pitch of teeth (B), and flow channel depth (D) to construct 128 emitters. Through simulation, we obtained q, the flow index (x), and the structural resistance coefficient (Cs) under the pressure (H) ranging from 0.02 to 0.15 MPa. The results showed that the rated flow rate (q0.1) and x values of 128 emitters range from 0.50 to 0.85 L/h and 0.461 to 0.480, respectively. Since Cs is negatively correlated with x, to obtain the combination of the flow channel structural parameters with the optimal hydraulic performance (x = min f(E, A, B, D)) and the optimal anti-clogging performance (Cs = min g(E, A, B, D)), the flow channel structural parameters are optimized by using the NSGA-II genetic algorithm to obtain the Pareto frontier solution. The optimal combinations of channel structural parameters corresponding to the q0.1 values of 0.62, 0.71, and 0.82 L/h with x of 0.470, 0.466, and 0.463 are obtained using the weighting method. Cs values are 0.131, 0.446, and 0.619, respectively. The limit laying length of the configured emitter is 150–180 m. According to the flow field cloud diagram before and after optimization, it can be found that increasing the high-velocity area and high-turbulent-kinetic-energy area in the main stream and decreasing the low-velocity area and low-turbulent-kinetic-energy area in the tooth base and downstream face can help reduce x and Cs, and thus improve the hydraulic performance and anti-clogging performance of the small flow rate emitter. [ABSTRACT FROM AUTHOR]

The involute profile is used almost exclusively in the manufacturing of spur gears. Nevertheless, in machinery design, the evaluation of environmental factors, such as energy efficiency, has become increasingly important when choosing between feasible solutions. As a result, the study of alternative profiles is gaining interest. The key novelty of this study is the comparative analysis of involute and cycloidal gear profiles with respect to frictional power losses in the tooth contact, as well as their impact on energy efficiency in spur gear transmissions. The coefficient of friction is approximated using two widely applied analytical lubrication models: the elastohydrodynamic and mixed elastohydrodynamic, both of which provide enough accurate values with a reasonable amount of computation burden in comparison with numerical methods. An additional contribution of this study is a sensitivity assessment of the energy efficiency of the cycloidal profile with regard to the auxiliary centrode diameters. This allows for an understanding of the geometrical constraints of this profile, specifically the maximum pressure angle—which is related to the radial loads applied to the shaft—and the tooth height—which is related to the bending moment at the tooth root—and hence, setting the appropriate ones to be equivalent to the involute profile. For the comparative analysis, equivalent profiles are selected based on similar tooth bending moments and radial loads supported by the shaft. After determining the centrode diameters of the cycloidal profile, the efficiency of both gear profiles and their sensitivity to gear size and gear ratio are compared. This study concludes that, for both profiles and friction analytical models, efficiency improves with increasing gear sizes and gear ratios, eventually converging to a constant value. Furthermore, both cycloidal and involute profiles exhibit comparable performance in terms of energy efficiency across both lubrication analytical models. [ABSTRACT FROM AUTHOR]

The China Bearing Reducer (CBR) is a single-stage cycloid reducer with a compact structure, primarily used in high-precision fields such as robotic joints and Computer Numerical Control (CNC) machine tool turntables, where strict requirements for transmission accuracy are necessary. Tooth modification and manufacturing errors in the cycloid gear are two important factors affecting the transmission accuracy of CBRs. In this paper, the transmission performance of the CBR is studied using a new tooth modification method that considers manufacturing errors. Firstly, the structure of the CBR is introduced, and a new method known as Variable Isometric Sectional Profile Modification (VISPM) is proposed. Secondly, the Tooth Contact Analysis (TCA) model is constructed using the VISPM method, and a method for reconstructing the tooth profile with cycloid tooth profile error based on B-spline curve fitting is proposed. The TCA is carried out with both VISPM and tooth profile error. The influence of the modification parameters on meshing characteristics, such as contact force, contact stress, contact deformation, and transmission error, is analyzed. Thirdly, the optimization of the modification parameters is conducted using Particle Swarm Optimization (PSO) to determine the optimal VISPM and isometric and offset modification (IOM) parameter values. The results indicate that the VSIPM method is superior to the IOM method in enhancing meshing characteristics. A physical prototype of the CBR25 is manufactured using the optimized VISPM and IOM, and the transmission error is tested on an experimental platform. The test results demonstrate that the ETCA method is corrected for cycloid drive analysis. [ABSTRACT FROM AUTHOR]

Objectives: Mandibular molar distalization is a complex orthodontic movement due to anatomic and biomechanical limitations. The opportunity to use a custom-made appliance with skeletal anchorage should be an advantageous alternative to traditional solutions: multiple extractions, interproximal reductions, vestibular inclination of incisal group. Methods: A 14-year-old female patient with Class II malocclusion and ectopic upper and lower canines was treated in the lower arch with a custom-made appliance anchored on a mini-screw in the right buccal-shelf where the ectopy and crowding was severe. The miniscrew was connected to a rigid arm with a rail equipped with a coil that activated promoted the distalization of first and second molars bonded with metallic bands. Results: After 8 months of treatment with activations repeated every 4 weeks, an effective distalization has been reached. Conclusions: Mandibular molars' distalization is a challenging orthodontic result to achieve. When the need to obtain space cannot be beneficially obtained with conventional approaches, and distalization of the lower molars could be desirable, a custom distalization device with skeletal anchorage and biomechanics based on a pressed coil sliding on a rigid arm is an efficient solution. [ABSTRACT FROM AUTHOR]

Background/Objectives: The aim was to evaluate the agreement between plaque detection with an intraoral scanner system (IOS) and a conventional clinical method and to evaluate the inter-rater reliability for scoring 3D models with and without a disclosing agent. Methods: A total of 14 participants were recruited from the Department of Operative Dentistry, School of Dentistry, National and Kapodistrian University of Athens. Participants eligible for inclusion were adults with good general health and a minimum of 20 teeth. Participants were clinically examined with plaque assessment according to the modified Quigley–Hein plaque index before and after using a disclosing agent (GC-Tri Plaque ID-Gel, GC, Europe N.V). Before and after the application of the disclosing agent, all study participants were scanned using the IOS (TRIOS5, 3Shape TRIOS A/S). The clinical examiner and three additional examiners blinded to the clinical examination assessed plaque status on the acquired 3D models with and without disclosing agent using the same index to evaluate the inter-rater agreement. Intraclass coefficient correlation, one sample t-test, and Cronbach's α for inter-rater reliability were calculated. Results: All methods showed moderate to strong correlations (Spearman's rho ranging from 0.527 to 0.618), and Cronbach's α ranged from 0.551 to 0.766. Conclusions: The level of agreement between conventional clinical registration and registration from 3D models was acceptable overall. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this in vitro study was to evaluate and compare the fracture resistance of endodontically treated teeth using three different intra-orifice barriers. Settings and Design: This study was conducted at the department of conservative dentistry and endodontics, an in vitro study. Subjects and Methods: Forty freshly extracted single-rooted mandibular bicuspids (n = 40) were decoronated to obtain a 14-mm standard root length and all the canals were enlarged with ProTaper up to size F3 and they were obturated with gutta-percha using AH Plus sealer and randomly divided into 4 groups (n = 10). Group I: Control group obturated with gutta-percha only. Groups II, III, and IV had placement of intra-orifice barriers after the removal of 3-mm coronal gutta-percha such that Group II: Ever X posterior; Group III: Beautifil II; and Group IV: Tetric N-Ceram. Mounting of specimens was done in acrylic resin to expose coronal 3 mm and tested using the universal testing machine. Statistical Analysis Used: Data were analyzed for significance by ANOVA and Tukey's post hoc test. Results: Ever X posterior group showed better fracture resistance and the control group is the least among the groups. Conclusions: Placement of intra-orifice barriers significantly improves the fracture resistance compared with the control group. [ABSTRACT FROM AUTHOR]

Aim: The aim of the study was to evaluate and compare two techniques of shade matching using VITA shade guide under color-corrected light and mobile application DentHue with VITA shade guide under natural light. Materials and Methods: 100 subjects were selected for the study. The visual assessment was based on a comparison between a shade guide and the target tooth. The shade of the tooth was assessed using VITA classical shade guide in natural daylight, using VITA shade guide with a color-corrected light (true light) and a mobile application DentHue. The shade matching using color-corrected light and with the application was compared with that done by VITA shade guide. Results: It was found that there were 69 (69%) correct identifications of the shade when matched under color-corrected light while 31 (31%) were incorrectly identified. It was also found that there were 38 (38%) correct identifications performed by DentHue while there were 62 (62%) incorrect identifications of the shade. This difference was statistically significant (P < 0.05). Conclusion: The use of color-corrected light demonstrated superior accuracy in shade matching using the VITA shade guide as compared to DentHue. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to compare the biomechanical performance of endocrown-retained and post-and-core-retained fixed partial dentures (FPDs), focusing on stress distribution, tensile, and shear stress. Materials and Methods: Finite element analysis was used to simulate occlusal loading on two FPD designs: endocrown-retained zirconia and post-and-core-retained zirconia which were subjected to a simulated occlusal load of 150 N. Stress distribution was analyzed using von Mises stress, tensile stress, and shear stress. Material properties for zirconia, resin cement, enamel, dentin, bone, Periodontal ligament (PDL), and fiber post were incorporated. Results: The endocrown design showed lower von Mises stress (176.35 MPa) than the post-and-core design (298.29 MPa). It also had lower shear stress at the cement interface and reduced stress on abutment teeth. Conclusion: Endocrown-retained FPDs provide better stress distribution and structural integrity, offering a reliable, minimally invasive option for restoring endodontically treated molars. Clinical Significance: Endocrown retained 3-unit fixed partial denture can be a promising alternative to the fiber-post retained FPD for restoring molars with extensive tooth loss. [ABSTRACT FROM AUTHOR]

Rhyssoplax olivacea is the most common Mediterranean polyplacophoran species; however, no information exists regarding the functionality of its skeleton. The present study describes allometric trends related to its valves and radula and examines their chemical composition using specimens from the Aegean Sea, eastern Mediterranean Sea. Differences in valve width and thickness were found among all three valves; in particular, the intermediate valve had a significantly shorter length compared to the two terminal ones. The intermediate valve exhibited different trends for valve length to valve width and valve length to valve thickness compared to the terminal valves. However, all valve morphometrics to body length appeared to adhere to a shared trend. The radula to body length exhibited positive allometry. Regarding the elemental composition, all three valves appeared to have similar elemental compositions; however, the element concentrations in the radula differed with the tooth type. Iron was always the dominant element, with the highest values reported for the major lateral tooth (83% wt%). This study provides valuable insights into the different aspects of the skeleton of R. olivacea, enabling future research to focus on the skeletal functionality from evolutionary and ecological perspectives. [ABSTRACT FROM AUTHOR]

This review synthesizes the findings from 252 studies to explore the relationship between the oral pathogens associated with periodontitis, dental caries, and systemic diseases. Individuals with oral diseases, such as periodontitis, are between 1.7 and 7.5 times (average 3.3 times) more likely to develop systemic diseases or suffer adverse pregnancy outcomes, underscoring the critical connection between dental and overall health. Oral conditions such as periodontitis and dental caries represent a significant health burden, affecting 26–47% of Americans. The most important oral pathogens, ranked by publication frequency, include the herpes virus, C. albicans, S. mutans, P. gingivalis, F. nucleatum, A. actinomycetemcomitans, P. intermedia, T. denticola, and T. forsythia. The systemic diseases and disorders linked to oral infections, ranked similarly, include cancer, respiratory, liver, bowel, fever, kidney, complications in pregnancy, cardiovascular bacteremia, diabetes, arthritis, autoimmune, bladder, dementia, lupus, and Alzheimer's diseases. Evidence supports the efficacy of dental and periodontal treatments in eliminating oral infections and reducing the severity of systemic diseases. The substantial burden that oral pathogens have on cancer, cardiovascular diseases, Alzheimer's, diabetes, and other systemic diseases poses a significant public health crisis. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the scanning time and marginal fit of CAD/CAM crowns fabricated using different intraoral scanning systems (IOS) (O1—Omnicam 1.0, O2—Omnicam 2.0, PS—Primescan). A standardized, 3D-printed composite resin die with a full-crown tooth preparation was scanned ten times with each IOS, and the scanning time was recorded. Subsequently, lithium disilicate ceramic crowns were designed and milled. The crowns were seated in the die and scanned using micro-computed tomography to assess the marginal fit. Fifty-two measurements were performed for each crown. Data were assessed for homogeneity, and one-way analysis of variance and the Tukey HSD test were performed (α = 0.05). For the analysis of vertical fit categories, the chi-square (Fisher's exact) test (α = 0.05) was used. The mean vertical fit values were: O1—46.7 ± 16.4 μm, O2—33.8 ± 21.4 μm (p = 0.041), and PS—12.3 ± 6.6 μm (p < 0.001). The vertical fit values were further categorized by percentage and representative specimens were scanned with electron microscopy to evaluate adaptation. The mean scanning times were: O1—37.4 ± 3.1 s; O2—34.8 ± 2.7 s; and PS—27.8 ± 1.9 s. Significant differences were observed in the scanning times and marginal fit values of the CAD/CAM ceramic crowns across the different IOS systems, with PS demonstrating the best results. Improvements in IOS hardware and software significantly influence these outcomes. [ABSTRACT FROM AUTHOR]

Although traditional dental-implant approaches have served as primary solutions, they are limited by infection risks, complications, and prolonged failures. Hybrid electrospun nanofiber matrices based on biomaterials have emerged as compelling alternatives for dental-tissue regeneration, offering direct cell-matrix contact and facile modification to incorporate anti-inflammatory, angiogenic, antimicrobial, and osteogenic properties. In this review, we discuss the advancements in hybrid nanofiber matrix-based approaches in dental-tissue engineering over the past five years (2019–2023). Beginning with an exploration of dental tissues and tooth structures, we discuss the innovative strategies in each study, including fabrication methods, physicochemical and biological properties, and osteogenic potential. We anticipate that ongoing research will enable the widespread application of innovative biomaterials and nanofiber matrices in future dental therapies. [ABSTRACT FROM AUTHOR]

Traditional orthodontic treatment relies on subjective estimations of orthodontists and iterative communication with technicians to achieve desired tooth alignments. This process is time-consuming, complex, and highly dependent on the orthodontist's experience. With the development of artificial intelligence, there's a growing interest in leveraging deep learning methods to achieve tooth alignment automatically. However, the absence of publicly available datasets containing pre/post-orthodontic 3D dental models has impeded the advancement of intelligent orthodontic solutions. To address this limitation, this paper proposes the first public 3D orthodontic dental dataset, comprising 1,060 pairs of pre/post-treatment dental models sourced from 435 patients. The proposed dataset encompasses 3D dental models with diverse malocclusion, e.g., tooth crowding, deep overbite, and deep overjet; and comprehensive professional annotations, including tooth segmentation labels, tooth position information, and crown landmarks. We also present technical validations for tooth alignment and orthodontic effect evaluation. The proposed dataset is expected to contribute to improving the efficiency and quality of target tooth position design in clinical orthodontic treatment utilizing deep learning methods. [ABSTRACT FROM AUTHOR]

Dental restorative resin composites are widely used to repair tooth decay owing to attractive esthetics, adequate mechanical properties and minimally invasive tooth structure preparations. Nevertheless, dental restorative resin composites still face challenges because of their relatively high failure rate and short lifespan caused by secondary caries and bulk fracture. Thus, attempts have been carried out to explore a new generation of dental restorative resin composites with antibacterial, remineralizing, and self-healing capabilities to inhibit bacteria and lengthen the lifetime of the restorations. Such novel restorative composites can inhibit bacterial activity, reduce acid production, promote mineral regeneration and present a renewable advantage to achieve a higher performance, which are inspiring and provide support for further basic and clinical research. In this review, antibacterial dental restorative resin composites are first introduced, followed by remineralizing, self-healing, and multifunctional dental resin composites with two or more of the functions mentioned above. Meanwhile, we explain the mechanism of the corresponding dental restorative resin composites and describe their characteristics. Finally, we conclude and put forward prospects. This review will attract both researchers and clinicians in this field and help to provide innovative ideas to design new restorative resin composites for biomedical applications. [ABSTRACT FROM AUTHOR]

Introduction: Although with increasing popularity due to aesthetic appeal and comfort, clear aligners (CAs) are facing challenges in efficacy and predictability. Advancement in the underlying biomechanical field is crucial to addressing these challenges. This paper endeavors to provide a comprehensive framework for understanding the biomechanics of CA and enlightening biomechanics-based improvements on treatment strategies. Methods: A thorough review of the English-language literature accessible through PubMed and Google Scholar, without any publication year restrictions, was undertaken to unravel the biomechanical aspects of CA. Results: This review presented an up-to-date understanding of aligner biomechanics arranged by the framework of the material-dependent mechanical characteristics of CA, the geometric characteristics-dependent force transmission of the CA system, methods for studying the biomechanics of CA, and the biomechanical analyses for different types of tooth movement. Conclusions: Biomechanics should be the fundamental concern for concepts, methods and adjuncts attempting to enhance the accuracy and predictability of tooth movement induced by CA. Improvement on material properties and alteration of geometric design of CA are two main approaches to develop biomechanically optimized force system. Exploration of real-world force sensing and monitoring system would make substantial progresses in aligner biomechanics. [ABSTRACT FROM AUTHOR]

As the core component of the all-metal micro resonant gyroscope, the structural parameters and form and position errors of the resonator significantly influence its vibration characteristics, and consequently, the accuracy of the gyroscope. By establishing the finite element model of an ideal hemispherical resonator and optimizing the meshing method, we refined the frequency difference to 0.1 Hz, enhancing the accuracy of the simulation model. Through finite element simulation, we examined the impact of various structural parameters and processing errors on the natural frequencies of each mode. We analyzed how form and position errors, including shell thickness error, central axis error, equatorial plane error, and edge rectangular tooth position error, affect the frequency splitting of the resonator. We provided optimization suggestions for the structural parameters, ensuring frequency splitting variations of less than 1 Hz. Theoretical modeling and simulation analysis indicated that the primary factors influencing the vibration modes and frequency splitting are the rectangular tooth structure and shell thickness. Following the optimized parameters, the frequency splitting of the All-Metal Micro Resonant Hemisphere was reduced by an order of magnitude to 14 Hz, demonstrating that these optimized conditions can significantly enhance the resonator's performance. [ABSTRACT FROM AUTHOR]

To study the multilevel coupled vibration of a naval gun under the foundation motion excitation of the ship, a mechanical-electrical-hydraulic coupled dynamic model of the naval gun including the follow-up systems' influence was established. The subprogram for calculating the ship foundation motion was written by the harmonic superposition method, and the motion in the 3 and 5-scale sea waves was reconstructed, respectively. Based on the multidisciplinary simulation, the transmission characteristics of the ship's foundation motion excitation along the naval gun and the influence of the tooth arc arrangement on the stabilization accuracy of the naval gun are analyzed. The results show that: the foundation motion excitation of the ship will aggravate the imbalance of the contact forces at the left and right trunnions of the cradle. A bilateral symmetrical arrangement scheme of the tooth arcs can reduce the contact forces' imbalance at the trunnions and reduce the adverse influence on the stabilization accuracy of the naval gun. The relevant research provides theoretical support and technical guidance for the structural design or verification of the naval gun. [ABSTRACT FROM AUTHOR]

Traditional dental prosthetics require a significant amount of work, labor, and time. To simplify the process, a method to convert teeth scan images, scanned using an intraoral scanner, into 3D images for design was developed. Furthermore, several studies have used deep learning to automate dental prosthetic processes. Tooth images are required to train deep learning models, but they are difficult to use in research because they contain personal patient information. Therefore, we propose a method for generating virtual tooth images using image-to-image translation (pix2pix) and contextual reconstruction fill (CR-Fill). Various virtual images can be generated using pix2pix, and the images are used as training images for CR-Fill to compare the real image with the virtual image to ensure that the teeth are well-shaped and meaningful. The experimental results demonstrate that the images generated by the proposed method are similar to actual images. In addition, only using virtual images as training data did not perform well; however, using both real and virtual images as training data yielded nearly identical results to using only real images as training data. [ABSTRACT FROM AUTHOR]

One of the most frequent post-extraction complications of posterior maxillary teeth is oroantral communication, which consists of direct communication between the maxillary sinus and the oral cavity. The recommendation is to make an immediate closure within the first 48 hours to avoid possible complications that may include an oroantral fistula or chronic sinus disease. Currently, different techniques have been described for closing communication, including various types of materials. Some of the techniques are exclusively oriented toward closure, while others seek to achieve bone regeneration by using bone substitutes for the subsequent placement of dental implants. The aim of this study is to describe a simple surgical technique for managing oroantral communication using a collagen sponge with hydroxyapatite and ribose and covering it with overlapping double layers of ribose cross-linked collagen membrane without fixation. [ABSTRACT FROM AUTHOR]

Laser interferometry is an effective method to measure the tooth flank topography errors, and the information of tooth flank topography can be obtained accurately by using interferometric image processing technology. However, in practical experiments, speckle noise and tooth flank stray light often lead to the reduction of segmentation accuracy, thus affecting the accuracy of measurement. At the same time, the traditional time-domain segmentation method has the problems such as fitting error and being difficult to determine the appropriate segmentation threshold, which will also affect the segmentation accuracy. Therefore, tooth region segmentation plays an important role in interference image processing, which can effectively improve the measurement accuracy. To solve this problem, this paper presents a tooth flank region segmentation method based on improved U-net neural network. Firstly, the SE attention mechanism was introduced into the traditional U-net architecture to improve the recognition accuracy of the tooth flank region, Secondly, the mapping relationship between the input and output of the network was established to enhance the generalization ability of the network by collecting the tooth flank object images and interference images under different lighting environments and incident angles as the training data set. Finally an experimental comparison was conducted between the methods presented in the article and traditional segmentation methods. The results show that the proposed method can effectively reduce the segmentation error introduced by the traditional method, the phase jump correction rate is about 75.6%, and the accuracy of the model is 96%, which improves the segmentation accuracy and measurement accuracy. This research has wide application potential in the fields of interference image, medical and remote sensing image processing. [ABSTRACT FROM AUTHOR]

The masticatory function comprises a highly organized and complex action, involving several elements, with the teeth being the main one. An adequate functional dentition, defined as a condition that guarantees masticatory function even when the dental arch is not complete, is vital for a good quality of life and general health, influencing nutrition and reducing the risk of chronic diseases. The OMS refers to functional dentition as the preservation of at least 20 natural teeth throughout life without the need for dental prostheses. However, this definition is a quantitative concept. Studies show that tooth loss, malocclusion, and periodontal disease or caries negatively affect masticatory ability, which can lead to broader health problems, including malnutrition and systemic diseases. Therefore, tooth distribution, occlusal contacts, and oral health are fundamental for effective mastication. Research indicates that to provide a dentition that facilitates adequate mastication and meets functional requirements, the presence of at least 10 teeth in each arch, six anterior contacts (i.e., an intact anterior dentition), and at least four posterior occlusal contacts is recommended. In conclusion, a functional dentition is not defined solely by the number of teeth present, but also by their distribution, occlusal contacts, and oral health. [ABSTRACT FROM AUTHOR]