Dynamic modeling and analysis of a split-torque transmission with a tooth crack fault

Cracked tooth syndrome (CTS) is challenging to diagnose and manage due to its variable clinical presentation, resulting in inconsistent conclusions across existing reviews. Although several systematic reviews have investigated interventions independently, the evidence remains disparate, highlighting the need for an umbrella review to consolidate the different pieces of evidence and address any inconsistencies, thereby informing clinical recommendations. This umbrella review will include published systematic reviews and meta-analyses focusing on treatment for CTS. Various databases like PubMed, Cochrane Library, Scopus, Embase, and Web of Science will be searched till June 01, 2025. Two reviewers will independently perform the article screening, study identification, data extraction, and risk of bias assessment using the AMSTAR-2 tool. Overlap between relevant primary sources will be evaluated with the Corrected Covered Area (CCA) method. Certainty of evidence will be determined using the GRADE approach. The results will be reported as a narrative synthesis accompanied by summary tables. There will be an inclusion of only English-language publications, and the possibility of language bias will be recognized. This umbrella review will offer a broad and detailed summary of the available evidence pertaining to the management of CTS to facilitate the implementation of more uniform, evidence-based clinical decisions. The review, through assessing the quality of the methods used, locating the points of agreement or dispute, and indicating the gaps in the research, will be a guide for both the present practice and the next research directions. PROSPERO CRD420250648720.

Cracked tooth syndrome (CTS) has become a therapeutic dilemma due to a lack of consolidated evidence guiding its management. This umbrella review synthesized evidence from published systematic reviews of therapeutic interventions in CTS. The protocol was registered in PROSPERO (CRD420250648720), and it was conducted according to PRISMA 2020 guidelines. The searches were conducted up to June 15, 2025, in PubMed, Cochrane Library, Scopus, and EMBASE. Two reviewers screened and extracted data independently. A Measurement Tool to Assess Systematic Reviews 2 was used to measure methodological quality, and a citation matrix and Corrected Covered Area (CCA) to measure overlap of primary studies. Ten systematic reviews were identified, and four of them satisfied the inclusion criteria; they included 30 separate primary studies (45 study entries). The CCA was 17%, indicating high overlap. Endodontic therapy followed by full cuspal coverage demonstrated the highest prognosis with 84%-96% survival, 82%-84% success rate, and a lower chance of extraction by 11.3 times. On the other hand, there was an association of noncrowned teeth with pulpal problems, failure of restoration, and recurring symptoms, particularly in the presence of deep periodontal pockets. Endodontic therapy followed by full cuspal coverage provides the most predictable outcome in CTS. More evidence ought to be augmented using standardized measures, patient-reported outcomes, and cost-effectiveness calculations.

Prediction of Pulpal Sequelae in Cracked Teeth with Reversible Pulpitis using Machine Learning Models.

This report evaluates the morphology-driven preparation technique (MDPT) for biomimetic restoration of a cracked maxillary first molar, focusing on its tooth-preserving benefits and clinical outcomes. A 36-year-old male presented with 2 months of masticatory pain and recent spontaneous pain in the upper right posterior region (Tooth 16). Examination revealed occlusal cracks, confirmed as cracked tooth syndrome radiographically. Treatment included microscopic root canal therapy (biomechanical preparation, irrigation, and hybrid obturation) followed by MDPT-based restoration. The minimally invasive approach preserved natural morphology using digital impressions (3Shape TRIOS 5) and placed a lithium disilicate veneer with dual-cure resin cement under optimized bonding protocols. MDPT achieved a complete pain resolution and functional restoration while preserving maximum dentin structure. Minimal preparation and immediate dentin sealing enhanced stability and reduced microleakage risk, with excellent esthetic integration. MDPT represents an effective biomimetic solution for cracked teeth, combining minimal invasiveness with optimal clinical outcomes. The technique demonstrates significant advantages in tooth structure preservation and restoration longevity. Comparative studies are needed to further validate its clinical benefits.

Purpose: This study evaluated the pathological effects of single posterior implant-supported fixed prostheses on adjacent and antagonistic teeth and investigated the influence of systemic diseases, occlusal conditions, implant site, and patient sex.Materials and Methods: A retrospective observational study was conducted on 100 patients who had received a single posterior implant and were followed for at least one year at Gangneung-Wonju National University Dental Hospital. Clinical and radiographic assessments compared adjacent and antagonistic teeth at the implant site (ex-perimental group) with the corresponding contralateral teeth (control group). Parameters included tooth cracks, cusp fractures, alveolar bone status, treatment history, and occlusal contact assessed using the Shimstock test. Associations with systemic diseases, occlusal contact, sex, and implant position were also analyzed. Statistical analysis was performed using the chi-square test with a significance level of 0.05.Results: The distal adjacent tooth at the implant site showed significantly higher mobility than the control group (p<0.05). In patients without unilateral mastication, periapical lesions in antagonistic teeth (p<0.05) and cracks in adjacent teeth (p<0.05) were more frequent. Diabetic patients demonstrated a significantly higher prevalence of alveolar bone loss and treatment history in both adjacent and antagonistic teeth (p<0.05). When no occlusal contact was present on the implant-antagonistic tooth, less alveolar bone loss was observed (p<0.05), whereas cusp fractures in adjacent teeth were more common. Male patients showed a higher frequency of cusp fractures and cracks in adjacent teeth (p<0.05).Conclusion: Single posterior implant-supported fixed prostheses can induce pathological changes in adjacent and antagonistic teeth. Implant treatment planning should consider systemic health, occlusal dynamics, sex-related differences, and long-term maintenance.

Morphological Characterizations and Mineralized Repair of Natural Tooth Cracks Via Self-Assembling Peptide Hydrogels

Preventive Endodontics: Mitigating Crack Development and Tooth Loss.

Survival of Endodontically Treated Cracked Teeth: A 10- to 15-Year Retrospective Study.

Background: Cracked tooth syndrome (CTS) is a prevalent, diagnostically challenging condition with heterogeneous symptoms and variable progression that can compromise pulpal and periodontal health. Aim: To synthesize contemporary clinical guidance on CTS encompassing diagnosis, nursing care, and laboratory considerations to inform patient-centered, team-based management. Methods: Narrative integration of clinical history/physical examination features, adjunctive diagnostic tools (magnification, fibreoptic transillumination, bite tests, vitality testing, radiography/CBCT), etiologic and epidemiologic determinants, treatment pathways from conservative stabilization to endodontic therapy or extraction, and interprofessional roles. Results: Early, structured evaluation improves localization and staging of cracks and enables timely stabilization. Direct bonded restorations and provisional external splinting relieve symptoms and reduce flexure; definitive cuspal coverage redistributes occlusal forces. Pulpal involvement or root extension worsens prognosis and may necessitate endodontic treatment with guarded long-term survival or extraction. Nurses augment outcomes through triage, education, and adherence support; laboratories optimize material selection, digital design, and splinting biomechanics. Conclusion: CTS outcomes improve when clinicians pair rigorous diagnostics with staged biomechanical control and clear expectation-setting, supported by coordinated nursing and laboratory contributions. Early detection remains the pivotal determinant of tooth preservation.

Background: Cracked tooth syndrome (CTS) is a prevalent, diagnostically challenging condition with heterogeneous symptoms and variable progression that can compromise pulpal and periodontal health. Aim: To synthesize contemporary clinical guidance on CTS encompassing diagnosis, nursing care, and laboratory considerations to inform patient-centered, team-based management. Methods: Narrative integration of clinical history/physical examination features, adjunctive diagnostic tools (magnification, fibreoptic transillumination, bite tests, vitality testing, radiography/CBCT), etiologic and epidemiologic determinants, treatment pathways from conservative stabilization to endodontic therapy or extraction, and interprofessional roles. Results: Early, structured evaluation improves localization and staging of cracks and enables timely stabilization. Direct bonded restorations and provisional external splinting relieve symptoms and reduce flexure; definitive cuspal coverage redistributes occlusal forces. Pulpal involvement or root extension worsens prognosis and may necessitate endodontic treatment with guarded long-term survival or extraction. Nurses augment outcomes through triage, education, and adherence support; laboratories optimize material selection, digital design, and splinting biomechanics. Conclusion: CTS outcomes improve when clinicians pair rigorous diagnostics with staged biomechanical control and clear expectation-setting, supported by coordinated nursing and laboratory contributions. Early detection remains the pivotal determinant of tooth preservation.

Symptomatic cracked teeth: Associations with patient-level and tooth-level factors-A case-control study.

ABSTRACTObjectivesThe Covid‐19 pandemic increased stress, which may have led to more bruxism, TMDs, and thus tooth fractures. While previous studies, primarily from specialized clinics, reported an increase in cracked teeth during the pandemic, this retrospective study aimed to assess whether similar trends were observed in a general dental practice in Bavaria, Germany, which remained fully operational throughout the pandemic.Material and MethodsPatient records from 2018 to 2023 (n = 4709 patients, 10,018 visits) were analyzed for symptomatic tooth fractures, categorized as wall/cusp fractures, incomplete cracks, or complete fractures.ResultsStatistical analysis using the Mann–Whitney U test revealed no significant differences in fracture incidence between pre‐pandemic (2018–2019), pandemic (2020–2021), and post‐pandemic (2022–2023) periods. Mandibular molars were the most frequently affected teeth (7.94%–12.43%), and composite restorations were most associated with fractures (51.85%).ConclusionsContrary to previous findings from endodontic practices, this study found no pandemic‐related surge in tooth fractures, suggesting that referral bias or patient selection in specialized settings may influence reported trends.

Vibration characteristic analysis of a two-stage spur gear transmission system with tooth crack and profile shifted

Time-Varying Mesh Stiffness Calculation and Dynamic Modeling of Planetary Gearboxes for Tooth Crack Detection

Objective: The aim of this study was to evaluate and compare the clinical behavior of indirect onlays/overlays made of lithium disilicate and composite resin and to investigate risk factors associated with restoration failures. Methods: 112 indirect partial coverage posterior restorations (onlays and overlays) placed in 51 adult patients between January 2014 and December 2020 were examined. The restorations were evaluated using selected FDI criteria (color match, surface gloss, anatomic form, fracture of restorative material, tooth cracks and fractures, marginal discoloration, marginal integrity and recurrence of initial pathology). The survival of the restorations was analyzed using Kaplan–Meier method. Risk factors (type of restoration, type of tooth, tooth vitality, smoking) were investigated using Cox regression analysis. Risk estimation was conducted for each evaluated criterion (p < 0.05). Results: For composite restorations, the estimated survival rate was 94.2% after 5 years, dropping to 74.3% in 7.9 years and continued falling to less than 60% after 8.2 years. On the contrary, for lithium disilicate restorations the estimated survival rate was 90.9% after 5 years, dropped to 85.2% after 5.5 years remaining stable thereafter. Lithium disilicate onlays demonstrated significantly better performance than lithium disilicate overlays. Cox regression analysis did not reveal any significant association between the survival of the indirect partial restorations and restoration material, tooth type, restoration type and history of endodontic treatment. However, smoking was found to be a statistically significant risk factor (p < 0.05). Conclusions: Lithium disilicate and composite indirect restorations exhibited comparable survival rates at the early observation period. However, lithium disilicate partial coverage restorations demonstrated more favorable clinical behavior compared to composite in the long term, with statistical significance observed in ceramic vs. composite onlays.

Background/Objectives: The expansion of National Health Insurance (NHI) coverage for dental implants in South Korea has substantially increased implant placements among older adults. While implants offer functional and esthetic benefits, their lack of periodontal ligaments alters occlusal force distribution, potentially increasing biomechanical stress on adjacent or opposing teeth. This study aimed to investigate the association between the increased number of dental implants and the incidence of cracked teeth following the introduction of implant insurance. Methods: A retrospective analysis was conducted using the Clinical Data Warehouse of Seoul St. Mary's Dental Hospital. Patients who underwent molar crown restorations between 2014 and 2022 were included. The incidence and clinical features of cracked teeth were compared before (2014-2015) and after (2016-2022) the introduction of implant insurance. Statistical analyses assessed differences in symptom presentation, pulp status, and treatment outcomes. Results: Among 5044 molars restored with crowns, 1692 were diagnosed with cracks. The incidence of cracked teeth significantly increased after NHI coverage for implants (25.5% vs. 32.6%, p < 0.001). Cases after insurance implementation showed fewer signs and symptoms at initial presentation (67.4% vs. 50.0%, p < 0.001), reduced irreversible pulpitis (37.2% vs. 25.8%, p < 0.001), and increased preservation of pulp vitality (46.9% vs. 57.8%, p < 0.001). These shifts may reflect changes in occlusal adjustment practices and earlier clinical intervention. Conclusions: The findings suggest a temporal link between increased implant placement and the rising incidence of cracked teeth. Implant-induced occlusal changes may contribute to this trend. Careful occlusal evaluation and follow-up are essential after implant placement, and further prospective studies are warranted to confirm causality and refine prevention strategies.

Nonlinear characteristics analysis of encased differential gear train containing tooth crack fault

The aim of this systematic review is to critically evaluate the current evidence regarding diagnostic value of contrast-enhanced cone-beam computed tomography (CBCT) in increasing the detectability of cracks and fractures in teeth. Literature was reviewed from PubMed, Science Direct, Web of Science, and Saudi Digital Library in January 2025. The searched keywords included "Cone-beam computed tomography", "CBCT", "Contrast agents", "Tooth cracks", and "Tooth fractures". Only articles in the English language were included. The final analysis included four publications that satisfied the eligibility requirements. The evidence indicates that CBCT imaging with contrast improves the sensitivity, specificity, and accuracy of diagnosis. Enhanced sensitivity and specificity were over 80%. Contrast-enhanced CBCT successfully reduced artifacts and detected subsurface cracks, with accuracy gains ranging from 4.4 to 72.1%. Imaging protocols affected the performance, while using sodium iodide, dimethyl sulfoxide, ethyl alcohol, and ethyl acetate produced the best accuracy (100%, p < 0.01). In contemporary dentistry, contrast-enhanced CBCT is a promising development. The use of contrast-enhanced CBCT imaging could significantly improve the diagnostic precision of teeth cracks and fractures identification, which could lead to earlier detection and advanced treatment planning with better patient outcomes. How to cite this article: Sabban H, Abdel-Wahed N. Effectiveness of Contrast Agents in Cone-beam Computed Tomography for Diagnosing Tooth Cracks and Fractures: A Systematic Review and Meta-analysis. J Contemp Dent Pract 2025;26(5):519-525.

This study presents the development of a vibration-based health monitoring system for internal combustion engine timing belts using advanced signal processing, statistical feature extraction, and artificial neural network (ANN) classification. Vibration signals were captured under six belt conditions one healthy and five faulty (Tooth Crack, Back Crack, Wear, Separated Tooth, and Oil Pollution)—and analyzed in the time, frequency, and time–frequency domains. Six statistical features (standard deviation, kurtosis, FM4, impulse factor, crest factor, and skewness) were extracted from each signal to characterize fault behaviour. The classification task was modelled as a multi-class problem, and results were fused using Dempster–Shafer Theory (DST) to improve diagnostic reliability. Analysis revealed that Separated Tooth and Oil Pollution were the most severe faults, exhibiting the highest deviations across all domains, while Wear showed signs of progressive degradation. Tooth Crack and Back Crack displayed moderate but detectable anomalies, and the healthy belt provided a stable baseline across all features. The DST-based classifier achieved high accuracy ranging from 96.90% to 99.34%, confirming the effectiveness of the proposed method. This research demonstrates that vibration signal analysis combined with soft computing techniques offers a robust solution for early fault detection and predictive maintenance of timing belts, potentially preventing catastrophic engine failure.