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ObjectivesThe aim of this study was to evaluate the use of a convolutional neural network (CNN) system for detecting vertical root fracture (VRF) on panoramic radiography.MethodsThree hundred panoramic images containing a total of 330 VRF teeth with clearly visible fracture lines were selected from our hospital imaging database. Confirmation of VRF lines was performed by two radiologists and one endodontist. Eighty percent (240 images) of the 300 images were assigned to a training set and 20% (60 images) to a test set. A CNN-based deep learning model for the detection of VRFs was built using DetectNet with DIGITS version 5.0. To defend test data selection bias and increase reliability, fivefold cross-validation was performed. Diagnostic performance was evaluated using recall, precision, and F measure.ResultsOf the 330 VRFs, 267 were detected. Twenty teeth without fractures were falsely detected. Recall was 0.75, precision 0.93, and F measure 0.83.ConclusionsThe CNN learning model has shown promise as a tool to detect VRFs on panoramic images and to function as a CAD tool.

Background This study aimed to evaluate the role of periodontal endoscopy in clinical decision-making for teeth with suspected vertical root fracture (S-VRF) and to assess the diagnostic accuracy of this procedure with respect to vertical root fracture (VRF). Methods A prospective cohort of 115 S-VRFs meeting the inclusion criteria was analysed. The teeth were independently evaluated by two endodontists and subsequently categorized into three groups based on the type of pre-endoscopic treatment: flap surgery (S group, n  = 56), endodontic treatment (R group, n  = 48), and extraction (E group, n  = 11). Periodontal endoscopic examination was performed for all the teeth, and treatment plans were reassigned based on findings. The diagnosis of VRF was confirmed by intraoperative crack identification or clinical failure within a 1-year follow-up period. Three cases were excluded because they were lost to follow-up. Results Compared with cone-beam computed tomography(CBCT), periodontal endoscopy was associated with a reduction in unnecessary nonsurgical treatment by 39.58% (19/48), reduced the incidence of unnecessary surgical treatment by 64.28% (36/56), and an increase in diagnostic accuracy by 49.1%.The sensitivity of periodontal endoscopy for VRF detection was 84.3%. Conclusions Periodontal endoscopy may enhanced clinical decision-making and was associated with a reduced incidence of unnecessary nonsurgical and surgical interventions in patients with S-VRFs.

This study aimed to evaluate the fracture resistance of immediate and delayed restorations after root canal treatment (RCT). Sixty human intact premolar teeth were used. Teeth were prepared disto-occlusally. After RCT, teeth were randomly divided into two groups according to restoration times (immediate or 3 months delayed). The three month delay was imitated by thermomechanical aging. Then, samples were divided into six subgroups ( = 10). While I (Composite resin), II (Flowable bulk-fill) and III (Ribbond+Flowable bulk-fill) were restored immediately, Groups IV, V and VI were restored with temporary filling material and stored in distilled. After subjected to thermo-cycling (2,500 cycles, 5-55 °C) and exposed to 60,000 cycles in a chewing simulator, Group IV (Composite resin), V (Flowable bulk-fill) and VI (Ribbond+Flowable bulk-fill) were restored. All of the teeth were fractured on the universal testing machine. Failure modes were analyzed using scanning electron microscope. Data were analyzed using the Shapiro-Wilk and two-way ANOVA tests . The highest fracture resistance was recorded in Group III while the lowest in Group VI. No statistically significant difference was observed among groups ( > 0.05). Most of the repairable fractures were seen in Groups I and II. Delaying the permanent restorations of teeth for 3 months did not affect fracture resistance. However, it was suggested to avoid delaying restorations for obtaining repairable surfaces.

Traumatic dental injuries are prevalent among children and adolescents, especially those between 6 and 12 years of age with varying degrees of severity. The complexities of their diagnosis, management and overall prognosis are compounded by their occurrence in combination. International Association of Dental Traumatology guidelines provide a systematic roadmap for the management of isolated dental trauma but the management of a combination of injuries is still left to clinicians’ discretion. This case report illustrates the uncommon occurrence of multiple luxation injuries, including avulsion, in an early adolescent female child, concurrently with complicated tooth fractures of maxillary anterior teeth and its 5 year sequelae. The multidisciplinary management of the traumatised teeth involved endodontic therapy and mesialisation of teeth, resulting in a successful aesthetic reconstruction. This report highlights the promising approach of orthodontic treatment combined with prosthetic and/or endodontic therapy to manage combination injuries.

Objectives The objectives of this retrospective clinical study were to describe characteristics of crown fractures in permanent teeth and to investigate the survival of pulp vitality and restorations in uncomplicated and complicated crown fractures. Materials and methods This retrospective study collected information from patients suffering from dental trauma who were treated between January 2004 and June 2017. The study population consisted of 434 patients (253 males/181 females; mean age 20.7 years) with 489 uncomplicated and 127 complicated crown fractures. The Kaplan-Meier survival curves and Cox proportional hazard regression analyses were performed to explore the data statistically. Results The mean observation time was 522 days. Uncomplicated crown fractures without luxation showed a higher success rate of 82.3% (345/419) than complicated crown fractures without luxation (72.3%, 73/101). An additional luxation in uncomplicated crown fractures resulted in significantly reduced success rates in terms of survival of the pulp and restoration. Direct restorations survived significantly better independent of the fracture mode than did adhesively reattached crown fragments. No superiority of mineral trioxide aggregate or calcium hydroxide as pulp capping agent in complicated crown fractures was documented. Approximately 85.5% of all complications occurred within 2 years after the accident. Conclusion The treatment of crown fractures resulted mostly in successful outcomes and only a moderate number of complications were observed. Clinical relevance Primary dental management of crown fractures should follow recently published clinical guidelines, and close monitoring over at least 2 years seems to be justified.

Exceptionally high rates of tooth fracture in large Pleistocene carnivorans imply intensified interspecific competition, given that tooth fracture rises with increased bone consumption, a behavior that likely occurs when prey are difficult to acquire. To assess the link between prey availability and dental attrition, we documented dental fracture rates over decades among three well-studied populations of extant gray wolves that differed in prey:predator ratio and levels of carcass utilization. When prey:predator ratios declined, kills were more fully consumed, and rates of tooth fracture more than doubled. This supports tooth fracture frequency as a relative measure of the difficulty of acquiring prey, and reveals a rapid response to diminished food levels in large carnivores despite risks of infection and reduced fitness due to dental injuries. More broadly, large carnivore tooth fracture frequency likely reflects energetic stress, an aspect of predator success that is challenging to quantify in wild populations. Gray wolves roam many European and American landscapes, where they prey on large animals such as elk and moose. A healthy dentition is essential for these predators to kill, eat and defend themselves. As a result, they tend to avoid biting down on tough body parts, such as bones, so that their teeth do not break. If food becomes scarce however, the wolves may resort to consuming these hard elements, eating more of the carcasses and leading to more damaged teeth. It could therefore be possible to assess the food levels available to existing (or even extinct) wolf populations based on how many broken teeth the animals have. However, older individuals are also more likely to have more damaged teeth, so age would need to be taken into consideration. Van Valkenburgh et al. decided to evaluate whether it was indeed possible to deduce how much food was available to groups of wolves based on teeth damage. Tooth wear and fracture were quantified in three current populations of gray wolves whose skulls had been collected and preserved in natural history collections. For each group, there were data available about the variations of number of moose per wolf over time, and how much of the carcasses the wolves were consuming. The analyses showed that indeed, when prey became less abundant, the wolves ate more of the remains – including the bones – and therefore broke more teeth. These conclusions can be applied to other large predators and even to extinct species such as dire wolves or sabertooth cats. Tapping into the potential of museum specimens could help to retrace environmental conditions and the history of animals now long gone.

ObjectivesTo make an in vitro assessment of fracture resistance of weakened and non-weakened teeth receiving intraradicular reinforcement using Rebilda bundled glass fiber–reinforced composite posts (GT), Rebilda conventional glass fiber posts (RP), or both systems combined (GT + RP).Materials and methodsEighty sound bovine incisors were prepared and divided randomly into eight groups as follows: (a) nWnR: without simulating weakness, and without intraradicular reinforcement; (b) WnR: simulating weakness, but without intraradicular reinforcement; (c) nWGT: without simulating weakness, but with GT; (d) WGT: simulating weakness, and with GT; (e) nWRP: without simulating weakness, but with RP; (f) WRP: simulating weakness, and with RP; (g) nWGTRP: without simulating weakness, but with GT + RP; (h) WGTRP: simulating weakness, and with GT + RP. The specimens were subjected to the load-to-fracture test using the DL-2000MF universal testing machine. The finite element method assessed the mechanical behavior and stress distribution in endodontically treated teeth.ResultsThe groups nWGTRP and WGTRP presented the best results in the load-to-fracture test, with the former being better than the latter, but with no statistically significant difference (P > 0.05). However, there was a significant difference between these and the other groups (P < 0.05), except for nWRP. Stress distribution inside the canal wall was different among the groups, with promising mechanical behavior for nWGTRP and nWRP.ConclusionsThe Rebilda conventional fiber post (RP), combined with the Rebilda bundled glass fiber–reinforced composite post (GT) improves the resistance and stress distribution of immature teeth.Clinical relevanceLongitudinal fracture is less frequent in teeth restored with GT and RP posts.

Background This study validated a patient-specific three-dimensional (3D) finite element (FE) model utilizing cone-beam computed tomography (CBCT) scans and occlusal records from a bruxism patient exhibiting a fractured right maxillary first molar. The model analyzed lateral mandibular movements linked to fracture initiation and evaluated its clinical utility in optimizing implant-supported prosthetic designs through biomechanical stress profiling. Method Lateral mandibular movements were simulated by the FE model from patient with bruxism to pinpoint the displacements that cause fracture-related stress concentrations. Three zirconia/resin implant crowns with cusp inclinations were modeled on the fracture geometry. Simulated biomechanical stress distribution was analyzed to assess effects on peri-implant bone, fixtures, and prosthetics. Results The pre-fracture model revealed stress concentrations coinciding with clinical root fracture sites during lateral mandibular movements defined by displacement parameters (x=-0.5 mm, y=-0.2 mm, z = 0 mm). In implant-supported prostheses, increased cusp inclination elevated stress in both implants and peri-implant bone, with zirconia crowns exhibiting higher stress than resin counterparts. The prosthetic abutment showed maximal stress concentration, approaching titanium’s yield strength at 30° inclination. Conclusions Three-dimensional finite element analysis (3D-FEA) effectively simulates abnormal occlusal stress directions in root-fractured teeth, proposing a novel clinical method to determine occlusal stress vectors. Additionally, for bruxism patients, implant prostheses should prioritize low cusp inclinations and use materials with low elastic modulus to mitigate stress concentration and mechanical complication risks.

This study aims to evaluate which splinting method offers the most favorable prognosis in cases of dental trauma involving horizontal intra-alveolar root fractures. Search strategies were adapted for seven electronic databases and gray literature to identify studies evaluating the prognosis of horizontal intra-alveolar root fractures based on the type of splint used. The risk of bias in the included studies was assessed using the Joanna Briggs Institute Critical Appraisal tools. A Bayesian network meta-analysis was conducted. A total of 3,174 references were retrieved, of which six studies met the inclusion criteria. No significant differences were found between the types of splints used and the healing outcomes of horizontally fractured intra-alveolar roots, including comparisons to cases without fixation. Across all studies, the degree of fragment displacement was a key factor influencing healing: the less displacement, the better the prognosis. Other treatment-related variables analyzed by the authors also played a role in determining tooth prognosis. There may be no difference regarding the type of splint used when considering the healing of horizontal intra-alveolar root fractures; however, other factors may have influenced this outcome. Understanding the fracture characteristics and the type of splinting intervention employed is essential for ensuring appropriate treatment in such cases.

Objectives This study evaluated factors associated with vertical root fracture in endodontically treated teeth, using a cone-beam computed tomography (CBCT) image database. Materials and methods The sample for this case-control study consisted of 81 CBCT scans of teeth with vertical root fracture (VRF) and 81 CBCT scans of non-fractured teeth, matched by age, sex, and tooth position. The analyzed variables included dentin thickness, an intraradicular post, an adjacent implant, and a missing adjacent tooth. Student’s t test test was used to compare the quantitative variables. The chi-square test was used to compare the categorical variables. Logistic regression was performed to evaluate the association between the presence of VRF and the independent factors assessed. Results The mean dentin thickness of fractured teeth was 1.3 mm, whereas that of non-fractured ones was 1.5 mm ( p  < 0.001). There was no difference between the fractured and non-fractured groups, regarding implant frequency or missing adjacent tooth ( p  > 0.05). There were a significantly larger number of teeth with posts in the fractured versus non-fractured group ( p  = 0.007). However, dentin thickness ≤ 1.3 mm was the only factor associated with VRF in the multiple regression model (OR = 3.60, 95%CI = 1.76–7.37). Conclusions Dentin thickness may influence the development of VRF. Dentin thickness ≤ 1.3 mm is associated with a greater likelihood of fracture than ≥ 1.4 mm. Clinical relevance This study suggests there may be a minimum amount of safe dentin thickness that should be preserved after endodontic instrumentation.