Validity of laser induced breakdown spectroscopy (LIBS) in determining age and sex from tooth specimens.

Background: To determine age and sex from tooth specimens using Laser-Induced Breakdown Spectroscopy (LIBS). Materials and methods: A total of 170 human teeth samples between age of 15-86 years of both male and female sex were obtained for the study based on the inclusion and exclusion criteria. All the tooth samples were mounted and ground sections of about 1.5-2 mm thickness were prepared. Each tooth sample was subjected to LIBS along the cemento-enamel junction and spectrographs were acquired that denoted the elemental presence in each tooth sample. Results: The elemental concentration of Ca I, Ca II, P and Fe in all the teeth samples declined as the age progressed. The Peak intensity of Ca, P and Fe was observed in the second decade of life. The overall concentration of Fe exhibited highest intensity in both male and female samples when compared with other elements assessed. The general concentration of all the elements were relatively higher in the female samples when compared to those in males. Conclusion: The CEJ seems to be a better site for elemental analysis of tooth since multiple tooth sites are represented in this region and the other sites of teeth such as enamel or roots of teeth may tend to get fractured, and my not be available for the analysis. The signal intensities of trace elements seen to reduce with increase in age. However, certain external factors also seemed to have an influence on these outcomes.

The Morphological Variation of the Soft Palate in Hospital Visiting Patients.

BACKGROUND: The soft palate anatomy of individuals can have a range of morphologies. Cephalometric analysis is a low-cost approach to analyze the soft palate in patients with or without developmental abnormalities. METHODS: The lateral cephalogram of the patients visiting Tribhuvan University Teaching Hospital, Institute of Medicine for various dental treatment purposes was evaluated. The soft palate was delineated on the radiographs by sketching the soft palate's contour along its radiolucent outline using the curve lines and connectors of Microsoft PowerPoint. The soft palate was then categorized according to the study by You M et al. Results: The different types of soft palate morphology observed in the study were rat tail (42.4%), leaf-like (40.8%), butt-like shape (8.9%), straight-line (4.7%), s-shaped (1.9%), and crooked (0.9%). The males had rat-tail (44.4%), leaf-like (41.1%), butt-like shape (8.4%), straight-line (3.9%), s-shaped (1.3%), and crooked (0.6%), whereas the females had rat-tail like (40.6%), leaf-like (40.6%), butt-like shape (9.5%), straight-line (5.6%), s-shaped (2.5%), and crooked (1.2%) types of soft palate. CONCLUSIONS: The rat-tail form of the soft palate was the most prevalent, followed by the leaf-like in both sexes. The least common type was the crooked form. This study found no evidence of sexual dimorphism.

Evaluation of the relationship between dermatoglyphics and mandibular third molar impaction: A cross-sectional study.

Background: Dermatoglyphics can be utilised in clinical settings to identify those who are more likely to have impacted teeth. Additionally, dermatoglyphics looks to have potential as a non-invasive diagnostic method for predicting the presence or absence of an impacted tooth. The goal of this study was to look at the most common dermatoglyphic pattern in people who had or didn't have an impacted mandibular third molar teeth and see if there was a dermatoglyphic signature. Methods: A cross-sectional study with 180 participants was conducted (90 cases and 90 controls). The rolling impression technique was used to apply blue duplicating ink to participants' fingertips, which was then recorded. There was an increase in the frequency of the whorl-plain pattern in the right-hand ring finger (60%; p=0.028) and left-hand little finger (33.3%; p=0.009), as well as the loop-ulnar pattern in the right-hand middle finger (74.4%; p=0.024) in individuals with a predisposition to the presence of impacted teeth. Results: The left-hand little finger was found to be the most predictive for impaction in a forward stepwise binary logistic regression analysis. Conclusions: Dermatoglyphics could be used as a non-invasive sign to predict whether or not a tooth is affected. Its value comes in early detection, which helps to avoid the surgical problems that come with symptomatic extraction of an impacted tooth.

A time based objective evaluation of the erosive effects of various beverages on enamel and cementum of deciduous and permanent teeth.

BACKGROUND: Erosion of the teeth is a chronic irreversible process leading to loss of surface enamel and even the dentin, in turn causing sensitivity and pain. Increased consumption of carbonated beverages remains a major cause for dental erosion. However, many of the so called safe beverages that are consumed may also have sufficiently low pH to cause dental erosion. One of the parameters to measure the dental erosion is estimation of hardness and surface roughness. Thus, this study aims to evaluate the difference in hardness and surface roughness of enamel and cementum using three beverages namely (carbonated drink, lime soda, lime juice) in deciduous and permanent teeth. MATERIAL AND METHODS: Ten permanent and three deciduous teeth samples each were kept in lime juice, lime soda, carbonated beverage and tap water. The VHN using Vickers hardness tester and Ra value using surface profilometer were assessed at baseline, 1 day and 10 days. RESULTS: At the end of 10 days the decrease in hardness of enamel of permanent teeth was maximum for teeth immersed in carbonated beverage followed by lime soda and lime juice. However, in the deciduous teeth it was observed that the VHN drop was maximum at 1 day in relation to teeth immersed in carbonated beverage followed by lime juice and lime soda. The hardness of cementum decreased significantly at the end of ten days both in deciduous as well as permanent teeth. CONCLUSIONS: The present study shows that many of the most commonly used beverages like lime juice and lime soda have a sufficiently low pH to cause erosion of the enamel surface as well as that of cementum of both deciduous and permanent teeth. Though protective mechanisms do exist in the oral cavity to neutralize the acids present in these beverages, continuous usage of these beverages leads to irreversible damage to the tooth structure. Key words:Dental erosion, hardness, surface roughness, permanent teeth, deciduous teeth.

Pattern-Corrected Mitotic Activity Index (PMAI): A Novel Prognosticator of Oral Squamous Cell Carcinoma.

OBJECTIVE: The main aim was to assess the efficiency of the Mitotic Activity Index (MAI) and a novel index devised by us, the Pattern-Corrected Mitotic Activity Index (PMAI) in prognostication of Oral Squamous Cell Carcinoma in terms of lymph node involvement, margin, recurrence and survival status. MATERIAL AND METHOD: The study group consisted of 60 cases of histologically-proven Oral Squamous Cell Carcinoma with known status of prognostic indicators. Hematoxylin and eosin stained sections of the tumor proper were utilized for assessment of mitotic activity and pattern of invasion. The Mitotic Activity Index and Pattern-Corrected Mitotic Activity Index were then calculated and correlated with the prognosticators. RESULTS: Mitotic Activity Index was higher in patients who had better survival and low recurrence rates. Pattern-Corrected Mitotic Activity Index showed the greatest percentage increase in relation to lymph node involvement as compared to the other indices. Kaplan Meier survival analysis showed that a higher Pattern-Corrected Mitotic Activity Index ( > 1.45) was associated with poorer survival (37.19 months). CONCLUSION: Lack of significant association of the Mitotic Activity Index in relation to prognosticators could be attributed to a tumor having a migratory phenotype rather than a proliferative phenotype as seen in late-stage tumors. Late-stage tumors have more of a poorer pattern of invasion which is reflected best by Pattern-Corrected Mitotic Activity Index by correlating with poorer survival and lymph node involvement.

A Comparative Evaluation of Stress Distribution with Two Attachment Systems of Varying Heights in a Mandibular Implant-Supported Overdenture: A Three-Dimensional Finite Element Analysis.

PURPOSE: To analyze and compare the stress distribution in an implant-retained overdenture complex using ball and Locator attachments of three heights by means of a 3D finite element analysis (FEA). MATERIALS AND METHODS: Six finite element models comprising an edentulous mandible with two interforaminal bone-level implants and ball attachments of heights 1 mm (A1), 3 mm (A3), and 5 mm (A5), and Locator attachments of heights 1 mm (B1), 3 mm (B3), and 5 mm (B5), were designed using ANSYS Workbench Software. Unilateral vertical (100 N) and oblique loads (100 N at 30° to the longitudinal axis of the implant in buccolingual direction) were applied. Average von Mises stress values were evaluated quantitatively and qualitatively. RESULTS: Locator attachments showed lower stress values as compared to the ball attachments in all examined areas. The increase in the height of both resulted in increased stress values. Higher values were observed at the implant neck in all models, as compared to the body and the apex. The recorded stress was higher in the cortical bone as compared to the cancellous bone. CONCLUSIONS: Within the limitations of the study, Locator attachments demonstrated lesser and more homogenous stress distribution in the implant-overdenture complex in comparison to ball attachments. The stresses generated within the tissues increase with an increase in collar height of the attachment system and therefore, attachments should be as short as possible for more favorable stress transmission.

Nuclear Fractal Dimensions as a Tool for Prognostication of Oral Squamous Cell Carcinoma.

BACKGROUND: Carcinogenesis follows complex molecular alterations, which are triggered by subtle chromatin architectural changes that are imperceptible to the human eye. As the treatment decisions in Oral Squamous Cell Carcinoma (OSCC) are hindered by the imprecise clinical stage determination and inter-observer variability in histological grading, focus in recent years has shifted to discovering identifiers related to neoplastic cell morphology studied through computer-aided image analysis. One such approach is the assessment of fractal geometry, a technique first described by Mandelbrot, which aids in precise assessment of architecture of natural objects. Assessment and quantification of degree of complexity of these fractal objects (self-similarities in structural complexity at different magnifying scales) is described as fractal dimension (FD). AIM: To evaluate the nuclear fractal dimension (NFD) in OSCC using computer-aided image analysis. MATERIALS AND METHODS: Histological sections of 14 selected cases of Oral Squamous Cell Carcinoma (OSCC) and 6 samples of normal buccal mucosa (as control) were stained with Haematoxylin-Eosin and Feulgen stain for histopathological examination and evaluation of nuclear complexity respectively. Fifteen HPF at Invasive Tumour Front (ITF) and Tumour Proper (TP) of Feulgen-stained sections were selected and photographed in test and control samples. At ITF, TP and normal buccal mucosa 200 nuclei each were selected and analyzed using Image J software to quantify FD. The test and control groups were compared statistically using Independent sample t-test and One-way ANOVA. RESULTS: Nuclear FD increased progressively towards worst tumour staging as compared to normal buccal mucosa. CONCLUSION: Nuclear FD can be considered for quantification of nuclear architectural changes as a prognostic indicator in OSCC.

Polarizing and light microscopic analysis of mineralized components and stromal elements in fibrous ossifying lesions.

INTRODUCTION: Fibro-osseous lesions, along with few reactive lesions of the jaws exhibit an overlapping histo-morphologic spectrum with respect to the nature of calcifications and stromal components. This causes difficulty in assessing the origin, pathogenesis and diagnosis of these lesions. AIM: The present study analyses the mineralized components, cellularity, stromal density and stromal composition (nature of collagen, presence of elastic and oxytalan fibres) in cases of ossifying fibroma (OF), fibrous dysplasia (FD) and peripheral ossifying fibroma (POF). MATERIALS AND METHODS: The study included a histochemical evaluation of six cases each of FD, OF and POF. Five consecutive sections of each case were stained with hematoxylin and eosin, picrosirius red (to assess maturation of fibres in polarizing light), van Gieson (for area fraction and collagen density) and aldehyde fuchsin (for elastic and oxytalan fibres) respectively. RESULTS: Significantly higher amounts of mature bone were seen in FD while cementicles having microlamellar pattern were predominant in OF and POF (p < 0.001). Area fraction, collagen density and immature stromal fibre content was higher in POF followed by FD and OF (p= 0.039). Oxytalan and elastic fibres were absent in FD. CONCLUSION: Higher cellularity of the stroma in OF was indicative of its neoplastic behaviour. Higher composition of oxytalan and elastic fibres in OF and POF supports their periodontal ligament origin. FD was distinct with more mature fibres in a lamellated bone and absence of oxytalan fibres.