Measure and compare the Degree of Root Canal Transportation and Canal-centering ability of Twisted, ProTaper, and Conventional Stainless Steel K Files using Spiral Computed Tomography: An in vitro Study.

AIM: The aim of this study was to compare canal transportation and centering ability of Twisted files (TF) and ProTaper (PT) files with conventional stainless steel (SS) K files. MATERIALS AND METHODS: Thirty mandibular premolar teeth with root curvature of 25 to 35° were selected. The samples were randomly divided into three groups of 10 each according to the type of files used for instrumentation. Group I was instrumented using TF, group II with PT files according to the manufacturer's recommendations, and group III with samples prepared with pre-curved SS K files using a step-back technique. After preparation, the samples were assessed using spiral computed tomography. Three sections were recorded at coronal, middle, and apical levels. Amount of transportation was assessed comparing with preinstrumentation images. Centering ability was calculated using Gambill's formula. The three groups were statistically compared using Student's t-test. RESULTS: Twisted files showed the least canal transportation and the best centering ability followed by PT file system. Stainless steel K files showed the highest transportation and least centering ability. CONCLUSION: Twisted files showed the least amount of transportation and better centering compared with the other file systems. CLINICAL SIGNIFICANCE: The study gives information of TF, a recently introduced rotary system (2008) with regard to its efficacy in preparing curved root canals. This study has shown that the centering ratio of rotary nickel titanium was better than that of SS files.

Independent Variables of Dental Erosion among Tertiary Care Hospital Patients of a Developing Country.

BACKGROUND AND AIM: Dental erosion is a multifactorial condition, which is mostly influenced by environmental factors. The aim of this study was to determine the prevalence of dental erosion, its associated risk factors, and their correlation with severity of the condition. MATERIALS AND METHODS: A total of 430 patients who attended the outpatient section of Government Dental College, Thiruvananthapuram, Kerala, India, were selected by systematic sampling method. Erosion was diagnosed by clinical examination and graded using Basic Erosive Wear Examination (BEWE) index. A pretested structured questionnaire on age, gender, medical history, medication history, and food habits was used. RESULTS AND CONCLUSION: Among the study population, 44% (95% confidence interval, 39.3%-48.7%) had dental erosion. Age above 45 years (79.7%, P = 0.000), male population (50%, P = 0.032), residents of rural area (49.1%, P = 0.000), patients with asthma (84.2%, P = 0.000), diabetes (90.9%, P = 0.000), gastroesophageal reflux disorder (91.7%, P = 0.001), and frequent consumption of orange (68.9%, P = 0.000) were identified as factors associated with erosion. The prevalence of dental erosion in the community was high. Results of the study established that better awareness of the condition, better facilities for its early diagnosis in the community, and development of proper preventive strategies are required to reduce the severity of dental erosion.

Evaluation and Comparison of the Biopathology of Collagen and Inflammation in the Extracellular Matrix of Oral Epithelial Dysplasias and Inflammatory Fibrous Hyperplasia Using Picrosirius Red Stain and Polarising Microscopy: A Preliminary Study.

BACKGROUND: The role of tumour inflammation and the dysplastic epithelial-stromal interactions on the nature of collagen fibres in the extracellular matrix of dysplastic epithelium is not fully understood. The present study was aimed to evaluate and compare the inflammation and pathological stromal collagen (loosely packed thin disorganized collagen) present in mild, moderate and severe epithelial dysplasias with that of inflammatory fibrous hyperplasias. The basement membrane intactness of epithelial dysplasias was also evaluated to determine if dysplastic epithelial mesenchymal interaction has any role in the integrity of stromal collagen in epithelial dysplasia. METHODS: Oral epithelial dysplasias, inflammatory fibrous hyperplasia and normal oral mucosal samples were used for the study. Packing, thickness and orientation of collagen fibres in mild, moderate and severe grades of oral epithelial dysplasias (n = 24), inflammatory fibrous hyperplasia (n = 8) and normal oral mucosal samples (n = 8) were analysed based on the polarisation of collagen fibres in picrosirius red polarising stain under polarising microscope. RESULTS: All the grades of epithelial dysplasias showed greenish yellow birefringence confirming the presence of loosely arranged pathological collagen in the presence of moderate inflammation. All the cases of inflammatory fibrous hyperplasia showed red polarisation hue and moderate inflammation. A statistically significant difference was found in the packing and orientation of collagen when epithelial dysplasias and inflammatory fibrous hyperplasia were compared (P < 0.01). When the intactness of basement membrane integrity was compared in all the groups of epithelial dysplasia, a statistically significant result was obtained (P < 0.05). CONCLUSIONS: Presence of significant amount of loosely packed thin disoriented collagen even in mild epithelial dysplasia suggests that tumourigenic factors are released to connective tissue stroma much earlier than expected. Hence we suggest considering the integrity of extracellular matrix collagen, intactness of basement membrane and inflammation associated with dysplasia along with the anaplasia of epithelial cells in the microscopic assessment of dysplastic epithelium.