Performance of Dental Students in Understanding and Retention of Oral Pathology Concepts: A Comparative Analysis of Traditional versus Live-Field Teaching Methods.

Background: Understanding oral aspects of pathology by traditional techniques has always been a paradigm in the field of dental education. Traditional methods of teaching include interaction using black board, projectors, and alternate methods of teaching such as a student-centered approach where live-field demonstrations, audio visual aids, and student interaction are also gaining importance, ultimately promoting active education. The aim of the study was to compare live-field and static-field teaching methods in understanding and retention of the histopathological features in dental students. Methods: This was a cross-sectional analytical study, wherein a uniform cohort of III-year dental students was obtained by randomizing the study subjects. Practical classes were conducted using traditional black board/static pictures and dynamic live-field teaching comprising of microscope connected to an HD screen and projector demonstrating the preferred microscopic field. Alternately, the level of retention of knowledge was measured using customized topic-based tests. The comparison of average scores was done between live-field and static-field teaching groups using the paired t-test. Results: The test scores using the paired t-test were marginally elevated in the conventional mode of teaching; however, it varied with respect to precise topics taken using both the genres of teaching. Conclusion: A balance of both conventional and virtual teaching needs to be achieved to enhance the comprehension in student learning. Nevertheless, in the impending years, advanced research is entailed to see if the virtual mode of teaching could replace the conventional method for the advancement in the study prospects.

Estimation of Age by Evaluating the Occlusal Tooth Wear in Molars: A Study on Dakshina Kannada Population.

PURPOSE: Assessment of teeth to estimate age in the living as well as the dead is well documented in the literature. Though applied in conjunction with other parameters in Gustafson's technique, attrition of teeth solely is an underexplored indicator for age estimation mainly in India. Most of the studies using attrition of teeth have been conducted in bioarchaeology, and in populations where studies are being conducted in forensic contexts, the results are debatable. Thus, the present study aimed to evaluate the accuracy of age estimation using the Average Stage of Attrition (ASA) method by Li and Ji in adults of the Dakshina Kannada region. MATERIALS AND METHODS: This cross-sectional study assessed the degree of attrition in both maxillary and mandibular first and second molars of 136 adults of Dakshina Kannada origin (age range: 20-70 years) according to the 10 stages given by Li and Ji to derive population-specific linear regression equations. RESULTS: Univariate analysis of prediction of age with attrition showed a significant association of attrition score with age, stratified by sex, arch as well as in total (p-value <0.001) with a standard error of estimate of 9.231 years. The estimated age was within ±5 years of the actual age in 44.2% of the females and 50.0% of the males. A comparative review of 23 studies done to estimate age from attrition score clinically is documented in the manuscript. CONCLUSION: The findings of this study suggest that evaluation of tooth wear by the Average Stage of Attrition (ASA) method can be used as a non-invasive means to aid in the determination of age in adults of Dakshina Kannada origin. Although the error increases with age, this method provides a measurable means of seriation into older and younger categories.

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 correlation of immunohistochemical expression of TP53 and CDKN1A in oral epithelial dysplasia and oral squamous cell carcinoma.

PURPOSE: Oral epithelial dysplasia (OED) occurs on exposure of epithelial cells to carcinogens and genetic alteration. Once the reversible cell damage is surpassed, cells either undergo apoptosis or transform into malignancy, chiefly oral squamous cell carcinoma (OSCC). Progressive accumulation of genetic errors (including mutations in TP53 and CDKN1A) is associated with the initiation and progression of potentially malignant oral lesions toward frank malignancy. The present study attempted to correlate the immunohistochemical expression of CDKN1A and TP53 with increasing severity of OED along with increased aggressiveness of OSCC as reflected in the clinicopathologic variables. MATERIALS AND METHODS: Tissue sections from forty biopsy-proven cases of OED and OSCC were stained with anti-TP53 and anti-CDKN1A mouse monoclonal antibodies. One hundred cells in each case were counted under high power magnification. RESULTS: Poorly differentiated OSCC showed the highest TP53 expression (mean = 70.285), with least expression seen in mild dysplasia (mean = 22.125) (P < 0.001). Higher TP53 count was seen in cases with margin involvement, without recurrence and lymph node involvement and in cases which died of disease. CDKN1A expression was seen only in five cases and that too focally in the cytoplasm, thereby warranting removal of analysis of CDKN1A positivity from the study. CONCLUSION: The expression of TP53 in OED highlights its role in initial carcinogenesis. Although the role of CDKN1A in the cell cycle has been documented, its relationship to various clinical and pathological variables of OSCC and its different treatment modalities could not be adequately assessed.

Computer-based method of bite mark analysis: A benchmark in forensic dentistry?

AIM: The study aimed to determine the technique with maximum accuracy in production of bite mark overlay. MATERIALS AND METHODS: Thirty subjects (10 males and 20 females; all aged 20-30 years) with complete set of natural upper and lower anterior teeth were selected for this study after obtaining approval from the Institutional Ethical Committee. The upper and lower alginate impressions were taken and die stone models were obtained from each impression; overlays were produced from the biting surfaces of six upper and six lower anterior teeth by hand tracing from study casts, hand tracing from wax impressions of the bite surface, radiopaque wax impression method, and xerographic method. These were compared with the original overlay produced digitally. RESULTS: Xerographic method was the most accurate of the four techniques, with the highest reproducibility for bite mark analysis. The methods of wax impression were better for producing overlay of tooth away from the occlusal plane. CONCLUSIONS: Various techniques are used in bite mark analysis and the choice of technique depends largely on personal preference. No single technique has been shown to be better than the others and very little research has been carried out to compare different methods. This study evaluated the accuracy of direct comparisons between suspect's models and bite marks with indirect comparisons in the form of conventional traced overlays of suspects and found the xerographic technique to be the best.

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.

Demirjian's method in the estimation of age: A study on human third molars.

AIM: The primary aim of the following study is to estimate the chronological age based on the stages of third molar development following the eight stages (A to H) method of Demirjian et al. (along with two modifications-Orhan) and secondary aim is to compare third molar development with sex and age. MATERIALS AND METHODS: The sample consisted of 115 orthopantomograms from South Indian subjects with known chronological age and gender. Multiple regression analysis was performed with chronological age as the dependable variable and third molar root development as independent variable. All the statistical analysis was performed using the SPSS 11.0 package (IBM ® Corporation). RESULTS: Statistically no significant differences were found in third molar development between males and females. Depending on the available number of wisdom teeth in an individual, R (2) varied for males from 0.21 to 0.48 and for females from 0.16 to 0.38. New equations were derived for estimating the chronological age. CONCLUSION: The chronological age of a South Indian individual between 14 and 22 years may be estimated based on the regression formulae. However, additional studies with a larger study population must be conducted to meet the need for population-based information on third molar development.

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.