Management of Localized Anterior Tooth Wear Using a Modified Sandwich Technique and the Dahl Concept: A Case Report

SUMMARY This case report illustrates a minimally invasive segmental rehabilitation of localized anterior tooth wear using a modification of the sandwich technique, a combination of indirect palatal composite veneers and direct labial composite restorations, at an increased occlusal vertical dimension (the Dahl concept).

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.

Sensor-integrating gears: wear detection by in-situ MEMS acceleration sensors

Gear tooth wear is a common phenomenon leading to malfunctions in machines. To detect wear and faults, gear condition monitoring by vibration is established. The problem is that the measurement data quality for detection of wear by vibration is not good enough with currently established measurement methods, caused by long signal paths of the commonly used housing mounted sensors. In-situ sensors directly at the gear achieve better data quality, but are not yet proved in wear detection. Further it is unknown what analysis methods are suited for in-situ sensor data. Existing gear condition metrics are mainly focused on localized gear tooth faults, and do not estimate wear related values. This contribution aims to improve wear detection by investigating in-situ sensors and advance gear condition metrics. Using a gear test rig to conduct an end of life test, the wear detection ability of an in-situ sensor system and reference sensors on the bearing block are compared through standard gear condition metrics. Furthermore, a machine-learned regression model is developed that maps multiple features related to gear dynamics to the gear mass loss. The standard gear metrics used on the in-situ sensor data are able to detect wear, but not significantly better compared to the other sensors. The regression model is able to estimate the actual wear with a high accuracy. Providing a wear related output improves the wear detection by better interpretability.

Evaluation of Tooth Wear and its Causative Risk Factors Amongst Patients Attending Dental Hospital of Karachi

OBJECTIVE: Tooth wear is a term defined as the loss of dental hard tissue in a damaged tooth if there is no existing dental caries or trauma. Tooth wear rarely exists alone and is observed clinically and experimentally in combination. Excessive tooth wear leads to hypersensitivity and exposed dentin. Tooth wear can be classified as attrition, erosion, abrasion. The frequency of normal tooth preservation is greater than ever, thus a better prevalence of tooth wear is experiential in the population. Therefore, the objective of the present cross-sectional study was to evaluate tooth wear and its causative risk factors amongst patients attending the Dental Hospital of Karachi. METHODOLOGY: The current study was a cross-sectional study conducted on adult patients recruited from the Out-Patient Department of Oral Diagnosis from May 2018 - December 2018. A consecutive sampling method was used and 250 adult patients aged 18-45 years were included. Tooth wear was assessed by using Smith and Knight Tooth Wear Index (TWI index).Data was entered and analyzed by using SPSS, frequency, percentages were calculated, and a chi-square test was performed to find the association between gender and risk factors. RESULTS: The subject populations of 250 were assessed. Out of which 178 were male (71.2%) and 72 (28.8%) were female with age ranging between 18 to 48 years old. In this study, 92.4% of them were suffering from tooth wear and only 31.2% have extended to the severe stage of the tooth surface loss. CONCLUSION: The present study concluded that there is an association between tooth wear and its risk factors. KEYWORDS: Tooth Wear; Dental Wear; Tooth Wear Indices; Sensitivity and Specificity; Risk Factors.

Dental Macrowear Reveals Ecological Diversity of Gorilla Spp.

Size and shape variation of molar crowns in primates plays an important role in understanding how species adapted to their environment. Gorillas are commonly considered to be folivorous primates because they possess sharp cusped molars which are adapted to process fibrous leafy foods. However, the proportion of fruit in their diet can vary significantly depending on their habitats. While tooth morphology can tell us what a tooth is capable of processing, tooth wear can help us to understand how teeth have been used during mastication. The objective of this study is to explore if differences in diet at the subspecies level can be detected by the analysis of molar macrowear. We analysed a large sample of second lower molars of Grauer’s, mountain and western lowland gorilla by combining the Occlusal Fingerprint Analysis method with other dental measurements. We found that Grauer’s and western lowland gorillas are characterised by a macrowear pattern indicating a larger intake of fruit in their diet, while mountain gorilla’s macrowear is associated with the consumption of more folivorous foods. We also found that the consumption of herbaceous foods is generally associated with an increase in dentine and enamel wear, confirming the results of previous studies.

Frequency of Tooth Wear amongst Adult Population Suffering from Diabetes Mellitus visiting Dental T. Hospital in Mardan

Objective: To conclude the frequency of tooth wear in permanent dentition of adults suffering from diabetes mellitus. Study Design: Cross-Sectional study Place and Duration of Study: Dental OPD of Bacha Khan College of Dentistry from 1st January 2021 to 30th June 2021. Methodology: Three hundred known diabetic patients who gave positive history of diabetes mellitus were randomly selected. Knowledgeable consent was attained from all subjects. Patients were clinically examined for tooth wear: erosion, attrition, abfraction and abrasion. Results: There were 166 (55%) males and 134 (45%) female patients respectively. The prevalence of tooth wear among diabetic individuals was as high as 62%. Conclusion: Diabetes mellitus is common disease in adult population and it cruelly impacts the oral health of an individual. Tooth wear is common finding in diabetic patients due to xerostomia. When patient is diagnosed as diabetic, the dentist should instruct the patient about the importance of hygiene care and risk of tooth wear and should carry out screening for tooth surface loss as a part of their routine dental examination in diabetic patients. Key Words: Tooth wear, Diabetes mellitus, Xerostomia, Attrition, Abrasion, Abfraction, Erosion

Pink Resin as an Alternative for Restoration of Cervical Lesions Associated with Gingival Recession: a Case Report

Gingival recession occurs when the gingival margin is located apically to the cementoenamel junction, causing root exposure. This work aims to report a clinical case of restorative treatment of multiple non-carious cervical lesions (NCCL´s) with gingival-colored resin, as an alternative approach of restorative procedure in cervical defects associated with gingival recession in the aesthetic area. A patient attended a Clinical-School complaining several NCCL´s in addition to Miller's class I gingival vestibular recession in the elements: 13, 21, 22 and 23. Dentin hypersensitivity was absent, however, aesthetic appearance bothered the patient. Presence of occlusal interferences, acid feeding and inadequate brushing habits were observed as important etiological factors for NCCL´s and gingival recessions. Periodontal surgery would be the treatment of choice, however, the patient needed orthodontic intervention first to promote dental alignment and correct distribution of the occlusal load. In order to decrease the progression of the lesions during the orthodontic treatment the NCCL´s associated with gingival recession were restored with gingival-colored resin. Two colors of pink composite resin (color G3 and G5) were incrementally inserted, promoting a correct emergence profile, taking the resin to the lower cavity limit avoiding aggression to the periodontal tissue. Clinical follow-up of 22 months was favorable due to the appearance of restorations and satisfactory periodontal health. Gingival resin can be assigned to improve the aesthetic effect of the restoration at a low cost and time-saving. Keywords: Gingival Recession. Tooth Wear. Composite Resins. ResumoA recessão gengival ocorre quando a margem gengival está localizada apicalmente à junção cemento-esmalte, causando exposição radicular. Este trabalho tem como objetivo relatar um caso clínico de tratamento restaurador de múltiplas lesões cervicais não cariosas (LCNC´s) com resina de cor gengival, como uma forma alternativa de procedimento restaurador em defeitos cervicais associados a recessão gengival em área estética. Uma paciente buscou atendimento odontológico em um centro especializado por apresentar várias lesões do tipo LCNC, além de recessão gengival vestibular classe I de Miller nos elementos: 13, 21, 22 e 23 que não apresentavam sensibilidade, porém eram lesões que a incomodava quanto ao fator estético. Foram observados importantes fatores etiológicos para as LCNC’s e recessões gengivais, como a oclusão desarmônica, alimentação ácida e hábitos de escovação inadequados. A cirurgia periodontal seria o tratamento de primeira escolha, contudo havia a necessidade de intervenção ortodôntica primeiramente para promover alinhamento dentário e correta distribuição das forças oclusais. Com o intuito de diminuir a progressão das lesões durante o tratamento ortodôntico optou-se por restaurar as LCNC´s associadas à recessão gengival com resina composta caracterizada para gengiva. Foram utilizadas 2 cores de resina rosa (G3 e G5) de forma incremental, até o limite inferior da cavidade, promovendo um correto perfil de emergência e evitando agressão aos tecidos periodontais. Acompanhamento clínico de 22 meses mostrou um aspecto favorável das restaurações assim como boa saúde periodontal. Dessa forma, a resina do tipo gengival pode ser indicada para melhorar o efeito estético da restauração a um baixo custo e rapidez no procedimento. Palavras-chave: Retração Gengival. Desgaste dos Dentes. Resinas Compostas.

The performance evaluation of heavy loaded tribosystems with vacuum ion-plasma PVD and DLC coatings

The results of studies of the physical, mechanical and tribological characteristics of PVD and DLC coatings are presented. The complex of basic mechanical properties (hardness H and elastic modulus E), as well as derivatives of mechanical characteristics H/E and Н3/Е2 , were investigated by the method of continuous indentation at various loads. The friction coefficient, the wear rate of the sample and the counterbody were determined as tribological indicators. The applied purpose of the work was to determine the friction unit for applying the developed coatings, materials and modes of applying PVD and DLC coatings. To solve this problem, a test bench was designed and built that simulates the operation of the selected friction unit. As a result of the research carried out, the results of laboratory and bench tests were compared. The performance of the coatings was determined by the volume of the tooth wear of the sleeve and the tip with the help of the method of micrometric measurements. As a result of the study of the surface morphology, the volumes of wear of rubbing conjugations and the intensity of their wear were determined. It has been established that the results of bench tests confirm laboratory studies and suggest that such an installation can be used for researching other heavily loaded spline conjugations.