Effectiveness of Visual-Tactile Examination and DIAGNOdent Pen in Detecting Early Enamel Caries and Its Remineralisation: An In Vitro Study

Background. The caries preventive effect of Colgate Duraphat® and GC Tooth Mousse Plus® has been widely studied, but the remineralisation potential of initial occlusal caries using these two remineralisation materials remains unclear. Aim. This study is aimed at evaluating and comparing the remineralisation of early enamel caries on the occlusal surface of permanent posterior teeth using ICDAS II caries scoring system and DIAGNOdent Pen (DDPen) after remineralisation with Colgate Duraphat® and GC Tooth Mousse Plus®. Materials and Methods. Extracted posterior teeth ( N = 120 ) with incipient occlusal caries were included in this study. The occlusal surface of each tooth was scored using DDPen and ICDAS II scoring before remineralisation. Then, remineralisation of the teeth of the experimental group was carried out using either CPP-ACP-F or fluoride varnish. After the remineralisation procedures, the occlusal surface of each tooth was again scored using DDPen and ICDAS II scoring. The teeth were then fixed in dental stone blocks and sectioned longitudinally for histological examination using a stereomicroscope. Statistical analysis was performed to calculate the sensitivity and specificity of DDPen and ICDAS II to detect remineralisation and compare with the gold standard histological examination. Results. According to ICDAS-II scores, a significant difference was noted in GC Tooth Mousse Plus® and Duraphat® study samples, whereas the difference between the pre-and post-remineralisation of the control group was not significant. According to the DDPen score criteria, a statistically significant difference was noted among all study groups; however, a greater significance level was noted in the GC Tooth Mousse Plus® and Duraphat® study samples compared with the control group. The Spearman’s rank correlation of ICDAS-II and DDPen with Downer’s histological score (gold standard) revealed a higher association of DDPen score (.738) as compared to ICDAS-II scores (.430). Conclusion. The study concluded that both ICDAS II and DDPen could detect remineralisation of early enamel occlusal caries. DDPen was more sensitive than ICDAS-II to detect remineralisation compared with the Downers histological scores.

Biomechanical Evaluation of the Mandibular First Molar After Simulated Occlusal Wear Using 3D Finite Element Analysis

PURPOSE：This study aimed to investigate the biomechanical basis of vertical tooth fracture occurring in the mesial root of the mandibular first molar. METHODS：We used 3D finite elements to analyze the stress distribution and transient displacement of the mandibular first molar after occlusal surface wear and tooth tilt. Based on four degrees of wear within each of the surface wear and tooth tilt groups, eight models were established in addition to the control model. A simulated bite force of 200 N was loaded on the occlusal surface, and nonlinear finite element analysis was used to explore the biomechanical basis of vertical root fracture. RESULTS：When the distal tipping angle of the abrasion plane of the mandibular first molar increased from 5° to 15°, the angle between the instantaneous displacement contours and the long axis of the tooth decreased. Meanwhile, the mesial root was found to suffer the highest stress concentration, and the possibility of longitudinal root fracture was increased. CONCLUSION: By evaluating the biomechanical effect of tooth wear and occlusal loading, we are able to identify some clinical interventions that may prevent vertical tooth fracture.

A Computerized Simulation of the Occlusal Surface in Equine Cheek Teeth: A Simplified Model

Equine mastication, as well as dental wear patterns, is highly important for the development of treatments in equine dentistry. During the last decades, the stress and strain distributions of equine teeth have been successfully simulated using finite element analysis. Yet, to date, there is no simulation available for dental tooth wear in equines. In this study, we developed a simplified two-dimensional computer simulation of dental wear. It provides a first tentative explanation for the development of the marked physiological inclination of the occlusal surface and for pathological conditions such as sharp enamel points in equine cheek teeth. The mechanical properties of the dental structures as well as the movement of the mandible during the equine chewing cycle were simulated according to previously published data. The simulation setup was optimized in preliminary test runs. Further simulations were conducted varying the lateral excursion of the mandible and the presence or absence of incisor contact during the chewing cycle. The results of simulations showed clear analogies to tooth wear patterns in living equids, including the formation of wear abnormalities. Our analysis indicates that small variations in the pattern of movement during the masticatory cycle, as well as incisor contacts, are leading to marked changes in the occlusal tooth wear patterns. This opens new research avenues to better understand the development of dental wear abnormalities in equines and might have serious implications on captive animal health, welfare, and longevity.

Pit and fissure sealants — A review

Caries on the occlusal surface of dentition is a significant dental health problem. Among all of the teeth particularly molars and premolars have greater susceptibility to caries. Their susceptibility to caries is probably related to its occlusal morphology. Use of fissure sealant and fluoride have been shown to play an important role in reducing caries. This can be possible through converting the caries susceptible areas like pits and fissures into glazed surface which prevent bacterial colonization and makes the tooth easy to clean. Pit and fissure areas of enamel do not receive sufficient protection from topical or systemic fluorides, the reason for ineffectiveness of fluorides in the pit and fissure caries may be due to inaccessibility to these areas and due to the differences in enamel thickness. The most efficient way to prevent pit and fissure caries is by effectively sealing the fissures using resins called pit and fissure sealants.

Overtreatment in Restorative Dentistry: Decision Making by Last-Year Dental Students

To evaluate the tendency for overdiagnosis and overtreatment upon different clinical situations among last-year students from the degree in dentistry from Valencia University (Spain) during the 2018–2019 course. A questionnaire consisting of 10 case exemplifications examining the diagnosis, treatment, and clinician’s attitude towards different common clinical situations regarding restorative dentistry was designed. Fifty-two students were surveyed, from whom 42 completed the questionnaire (80.77%). Data were analyzed descriptively. A total of 58.8% of the students correctly identified an early carious lesion in the occlusal surface of a molar, while 63.2% would perform unnecessary complementary tests for its diagnosis. The treatment for carious lesions in different evolutive phases with a vital pulp was correct between 51.2 and 92.7% of the cases. The treatment for irreversible pulp pathology and the restoration of the tooth with root canal treatment were adequately selected in 56.1% and 78.3% of the cases, respectively. For the repair of a faulty restoration, an overtreatment was proposed by 87.8% of the students. A tendency to perform unnecessary complementary tests for caries diagnosis was observed. Treatment caries proposals were in accordance with available evidence in the majority of the cases. Students tended to overtreat defective restorations and would perform unnecessary treatments in medically compromised patients.

Fracture Resistance of Equine Cheek Teeth With and Without Occlusal Fissures: A Standardized ex vivo Model

Background:Ex vivo fracture models are frequently used in human dentistry to provide insights in the fracture mechanisms of teeth. Equine cheek teeth fractures are an important dental pathology, but there has been no research performed to examine the fracture resistance ex vivo.Objective: To evaluate the fracture resistance of equine cheek teeth and identify anatomical predictors that might influence fracture resistance in healthy teeth. It was further evaluated if the presence of a fissure caused a decrease in fracture resistance.Study design:Ex vivo experimental design.Methods: Individual cheek teeth were subjected to a compression load in a universal testing machine until fracture occurred. Testing was performed in two study groups. A first group of healthy cheek teeth was tested to examine anatomical predictors on fracture resistance. A second group comprised cheek teeth with occlusal fissures and an equal number of age- and size-matched fissure-free teeth as controls. The effect of possible predictors on fracture resistance was investigated by regression analysis.Results: In the first group, fracture resistance was significantly influenced by the location on the tooth where testing was performed in both maxillary (p < 0.001) and mandibular teeth (p < 0.001). Additional significantly associated factors were Triadan number in mandibular (p = 0.009) and the mesiodistal length of the occlusal surface of maxillary teeth (p = 0.01). Experimentally induced crown fractures that extended below the simulated bone level were more frequently associated with pulp horn exposure (p < 0.001). In the second group, significant lower fracture loads were recorded in teeth with fissures (mandibular p = 0.006; maxillary p < 0.001), compared to fissure-free teeth.Main limitations: This ex vivo model does not imitate the in vivo masticatory forces and lacks the shock-absorbing properties of the periodontal ligament.Conclusions: The methodology used in this study provides an ex vivo experimental set-up to test fracture resistance of equine cheek teeth enabling evidence-based research to examine the potentially weakening effects of tooth pathology and its treatments. Crown resistance to fracture differed along the occlusal surface of healthy equine cheek teeth, and the presence of fissures further decreased fracture resistance.

IMPLANT TREATMENT IN PATIENTS WITH SEVERE TOOTH WEAR ON THE OCCLUSAL SURFACE

Examination along with implant treatment was carried out in 21 patients with severe tooth wear on the occlusal surface. This disorder features a variety of clinical symptoms including changes in the facial features and the lower jaw movement amplitude, disturbed canine and incisor guidance, supercontacts, asynchronous operation of the masticatory muscles, etc. We have proposed a treatment algorithm aimed at eliminating these issues. The temporary non-removable dentures allowed creating occlusal marks (Stage 1) followed with their transfer onto permanent orthopedic structure (Stage 2) using implants. The complexity of the approach to treating this disease, as well as the effectiveness of our method has been confirmed by clinical data and the outcomes obtained through an instrumental study involving electromyography and electronic axiography. The extra additional research methods employed, such as electromyography and electronic axiography, allowed to assess the activity of masticatory muscles and the lower jaw articulation, thus to ensure occlusal-articulation interaction when restoring the lower facial height.