Correlation Between Face Form and Maxillary Central Incisor Tooth Form in Dentate Patients Visiting Rehman College of Dentistry Peshawar

Aim: To determine the correlation between face form and maxillary central incisor tooth form in dentate patients visiting Rehman College of dentistry Peshawar. Methods: 152 patients fulfilling the inclusion criteria were included in the study through consecutive non probability sampling. Photographs of their face and maxillary central incisor were taken, printed, traced and subjected to classification by William’s method by 4 Prosthodontists. Results: As per descriptive statistics, mean and SD’s for age was 31+5.78, mean and SD’s for face form measurements was recorded as 78+1.67, whereas mean and SD’s for central incisor tooth form measurements was recorded as 25+0.69 Conclusion: It has been concluded that there is no highly defined correlation between the face form and maxillary central incisor tooth form in males and females. These results indicate that the maxillary central incisor tooth shows considerable asymmetry, whereas the face is basically symmetric. Instead, the opinions and desires of the patient should be considered, to ensure optimal dental esthetics for each individual. Keywords: Face form, Tooth form, Central Incisor, Correlation

Reconstructing dietary ecology of extinct strepsirrhines (Primates, Mammalia) with new approaches for characterizing and analyzing tooth shape

The morphological and ecological diversity of lemurs and lorisiformes once rivaled that of the rest of the primate order. Here, we assemble a dataset of 3D models representing the second mandibular molars of a wide range of extant and fossil strepsirrhines encompassing this diversity. We use these models to distill quantitative descriptors of tooth form and then analyze these data using new analytical methods. We employ a recently developed dental topography metric (ariaDNE), which is less sensitive to details of random error in 3D model quality than previously used metrics (e.g., DNE); Bayesian multinomial modeling with metrics designed to measure overfitting risk; and a tooth segmentation algorithm that allows the shapes of disaggregated tooth surface features to be quantified using dental topography metrics. This approach is successful at reclassifying extant strepsirrhine primates to known dietary ecology and indicates that the averaging of morphological information across the tooth surface does not interfere with the ability of dental topography metrics to predict dietary adaptation. When the most informative combination of dental topography metrics is applied to extinct species, many subfossil lemurs and the most basal fossil strepsirrhines are predicted to have been primarily frugivorous or gummivorous. This supports an ecological contraction among the extant lemurs and the importance of frugivory in the origins of crown Strepsirrhini, potentially to avoid competition with more insectivorous and folivorous members of Paleogene Afro-Arabian primate faunas.

Numerical Prediction of the Bending Fatigue Crack Propagation Behaviour in Asymmetric Spur Gears

The damage tolerance of a component is crucial for achieving a reliable and smooth operation. The crack propagation in a spur gear critically affects the performance of the transmission system. Asymmetric gears are used for enhancing the load-carrying capacity by increasing the pressure angle of a flank beyond the conventional limits. In this study, the effect of initial crack inclination angle and length in the tooth fillet region on the Stress Intensity Factor (SIF) and the crack path of an asymmetric gear (34°/20°) were studied using numerical simulations. Quasi-static analyses were performed in FRANC2D. The crack propagation life was calculated using Paris law. Results revealed that tooth asymmetry has no effect on the crack path. However, asymmetric tooth form caused a reduction in the SIF value and increased the critical crack length, leading to an increased crack propagation life and damage tolerance.

Paediatric dentistry

This chapter introduces the principal aims of treatment in paediatric patients, detailing examination, treatment planning, and prevention. Various approaches to behaviour management are discussed including tell, show, do; behaviour shaping; reinforcement; and desensitization. The emergency management of children with toothache is also discussed alongside developmental abnormalities (including abnormalities of tooth eruption and exfoliation, tooth number, tooth structure, tooth form, and tooth colour) local anaesthesia, and restorative techniques. Injuries to primary teeth and to permanent teeth are discussed. The chapter also provides advice on the management of dental trauma, with information on safeguarding children.

Testing the utility of dental morphological trait combinations for inferring human neutral genetic variation

Researchers commonly rely on human dental morphological features in order to reconstruct genetic affinities among past individuals and populations, particularly since teeth are often the best preserved part of a human skeleton. Tooth form is considered to be highly heritable and selectively neutral and, therefore, to be an excellent proxy for DNA when none is available. However, until today, it remains poorly understood whether certain dental traits or trait combinations preserve neutral genomic signatures to a greater degree than others. Here, we address this long-standing research gap by systematically testing the utility of 27 common dental traits and >134 million possible trait combinations in reflecting neutral genomic variation in a worldwide sample of modern human populations. Our analyses reveal that not all traits are equally well-suited for reconstructing population affinities. Whereas some traits largely reflect neutral variation and therefore evolved primarily as a result of genetic drift, others can be linked to nonstochastic processes such as natural selection or hominin admixture. We also demonstrate that reconstructions of population affinity based on many traits are not necessarily more reliable than those based on only a few traits. Importantly, we find a set of highly diagnostic trait combinations that preserve neutral genetic signals best (up to x∼r = 0.580; 95% r range = 0.293 to 0.758; P = 0.001). We propose that these trait combinations should be prioritized in future research, as they allow for more accurate inferences about past human population dynamics when using dental morphology as a proxy for DNA.

The Method of Estimating the Durability of Structural Materials from the Effects of Cyclic Loads

The article deals with the technique of predicting the durability of structural materials under the influence of low-cycle loads at different loading trajectories in a two-dimensional stress space at a flat stress-strain state. The use of this technique significantly reduces the number of time-consuming and expensive experiments while maintaining the quality of the results. The technique is based on the method of processing acoustic emission signals when the acoustic signals are allocated with a fractal dimension of the attractor 1≤ D2att ≤6 on a steady-state cyclic creep that reflects the accumulation of hazardous defects in the structural material. To predict the durability at a certain type of stress-strain state, but at any form of a cycle of low-cycle loading by the proposed method, it is enough to have the results of experiments at the maximum intensity of stresses, the minimum intensity of stresses and the saw-tooth form of the cycle of stress intensity change.

COMPOSITE BUILD-UP-CONSERVATIVE RESTORATION FOR A PERFECT SMILE.

BRIEF BACKGROUND The personality of a person is greatly influenced by their smile. Imperfections in the appearance of anterior teeth can reduce a person’s confidence and aesthetics. This case report represents the rehabilitation of a patient with severe tooth deformation in the upper and lower anterior teeth region. The tooth structure was not enough to support porcelain crowns, so Resin Composite was used to build up the tooth and it was supported using a periodontal splint. MATERIALS AND METHODS Clinical examination and radiographic evaluation showed a tooth form-size discrepancy. Due to the lack of tooth structure available for crown preparation, Resin Composite material was used to build up the tooth structure. everStick by GC was used as a periodontal splint to support the structure. DISCUSSION Resin Composite is one of the most conservative and aesthetic techniques available for restoring tooth structure. The different hues and shades available help it to provide a seemingly natural looking restoration. This helps in rehabilitation of a decrepit smile. Long term studies showed high success rates. Failure was seen in patients with paranormal muscle activity like bruxism and in bonding on pre-existing composite restorations. Marginal discolouration was seen in patients with tobacco habits (smoking and smokeless forms). SUMMARY AND CONCLUSION Composite build-up of teeth is a viable option for restoring tooth structure when the case demands aesthetic needs in both young and adult patients. The amount of tooth structure conserved is also much greater than with porcelain crowns. Cost of treatment is also significantly lower. KEY WORDS Composite, Aesthetics, Smile, Conservative treatment, everStick by GC.