Journal of Dentistry, Shiraz University of Medical Sciences
Volume:15 Issue: 2, Jun 2014

Statement of Problem: Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease with indefinite etiology. In recent researches, free radicals have been deliberated as the possible etiology of inflammatory and autoimmune diseases. This study was aimed to evaluate the stress oxidative status with the nitric oxide (NO) index in a sample of Iranian population. In this descriptive-comparative study, serum NO level was assessed in 20 OLP patients as the case group and 20 healthy individuals as the control group. Collected data were analyzed by adopting two Sample t-test, using SPSS 16 software. The statistical significance level was set at p< 0.05. The mean serum NO levels in OLP patients and healthy controls were 17.1±3.4 ng/ml and 14.5±2.7 ng/ml respectively; which revealed a significant statistical difference (p= 0.009). The results of the current study with its limitation may support the premise that higher serum levels of NO in patients with OLP might activate the process of lymphocytes and cellular immunity system; hence, possibly endorsing the effect of serum NO in pathogenesis of lichen planus.

Statement of Problem: Lichen planus is a chronic inflammatory immunologic-based disease involving skin and mucosa. This disease is generally divided into two categories: erosive and non-erosive. Many etiologic factors are deliberated regarding the disease; however, the disorders of immune system and the role of cytotoxic T-lymphocytes and monocytes are more highlighted. Zinc is an imperative element for the growth of epithelium and its deficiency induces the cytotoxic activity of T-helper2 cells, which seems to be associated with lichen planus. This study was aimed to evaluate the levels of serum zinc in erosive and non-erosive oral lichen planus (OLP) and to compare it with the healthy control group to find out any feasible inference. A total of 22 patients with erosive oral lichen planus, 22 patients with non erosive OLP and 44 healthy individuals as the control group were recruited in this descriptive-comparative study. All the participants were selected from the referees to the department of oral medicine, school of dentistry, Tabriz University of Medical Sciences. Serum zinc level was examined for all the individuals with liquid-stat kit (Beckman Instruments Inc.; Carlsbad, CA). Data were analyzed by adopting the ANOVA and Tukey tests, using SPSS 16 statistical software. The mean age of patients with erosive and non-erosive LP was 41.7 and 41.3 years, respectively. The mean age of the healthy control group was 34.4 years. The mean serum zinc levels in the erosive and non erosive lichen planus groups and control groups were 8.3 (1.15), 11.15 (0.92) and 15.74 (1.75) μg/dl respectively. The difference was statistically significant (p< 0.05). The serum zinc levels were decreased in patients with erosive oral lichen planus. This finding may probably indicate the promising role of zinc in development of oral lichen planus.

Statement of the Problem: Nanosilver particles have the potential to serve as a bactericidal agent because of the inherent antimicrobial influences of silver ion. The literature confirmed that specific micro-organisms, especially streptococci, have an important role as an etiological factor for caries. The aim of this study was to evaluate the antimicrobial effect of conventional and nanosilver-containing varnishes on oral streptococci. Pure cultivations of Streptococcus mutans and Streptococcus salivarius were prepared on blood agar media. Thereafter, 0.5 McFarland standard of recently grown bacteria in normal saline was prepared and the bacteria were cultivated monotonously on the culture medium surface by applying a swab. Different concentrations of nanosilver varnishes were prepared in the Mueller- Hinton broth medium in the test tubes and equal amounts of 0.5 McFarland suspension of all the tested bacteria were added separately to all test tubes. A tube without varnish was included as the control sample. The tubes were kept at 37°C for 24 hours, then cultured to determine the numbers of bacteria in each tube by counting colonies. The numbers of bacteria in tubes with varnish were compared to the numbers of bacteria in the tube without varnish. In the instance of observing any reduction in the growth, the minimum inhibitory concentration for growth in the tube with varnish was determined. Nanosilver varnish had an antimicrobial effect on S. mutans and S. salivarius. S. salivarius was more susceptible than S. mutans to the nanosilver varnish. Based on the results of this study, nanosilver varnishes can be used under amalgam restorations to reduce microbial population and subsequently preventing the recurrent caries.

Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence (LF). However, there are contradictory results in the influence of sealants on LF measurements. The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements. In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software. The mean value of LF measurements increased significantly due to the application of clear sealant (p= 0.001) while the statistical changes in this measurement was negligible after applying opaque sealant (p= 0.311). Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore DIAGNOdent device is not reliable for detecting caries beneath the clear sealant.

Statement of problem: Early childhood caries can cause pain, discomfort and also inability to have a healthy nutrition. Malnutrition can be characterized when there is a weight, height, and body mass index (BMI) deficiency. The aim of this study was to evaluate the relationship between the severe early childhood caries (based on the dmft index) and BMI in pre-school children in Shiraz. A descriptive analytical cross-sectional study was enrolled on 202 healthy preschool children with the age range of 3-6 years recruited from the kindergartens of different socio- economical parts of Shiraz, Iran. The Anthropometric measurements, weight and height were evaluated. The Z-scores were calculated employing WHO Anthro software (www.who.int/childgrowth/software/en/ index.html) to elucidate the subject’s status on the age- and sex-specific growth chart. Every Child who has received two Z-scores under the normal value (< -2) was considered as abnormal. The relationship between dmft index and BMI was then investigated. The mean of dmft was 4.13. From children with severe early childhood caries, 12.5%were under weight, 5% had height deficiency and 19.5% had BMI deficiency, however, there was no significant relationship between increasing dmft and the height, weight and BMI deficiency. There was not a linear correlation between severe early childhood caries and BMI, height, and weight deficiency. An incidence of 55% was yielded for severe early childhood caries which was an additional finding of this study.

Statement of Problem: Resin composites are brittle materials and their major shortcomings are manifested in their sensitivity to flaws and defects. Although various mechanical properties of resin composites have been described, few studies are available on assessing the effect of bleaching agents on resin composites using the short rod design. To place various resin composites into distilled water at 37°C for 21 days and determine the effect of immersion time in distilled water, with and without exposure to 10% carbamide peroxide by employing short rod design fracture toughness test. Specimens were prepared from three resin composites; Rok (SDI), Esthet (Dentsply), and Estelite (Tokuyama). For each material, a total of 24 disc-shaped specimens were prepared using a custom-made mould. Specimens were randomly divided into 3 groups of 8 and conditioned in 37°C distilled water for either 24 hours, or 21 days. 21 day specimens were tested both with and without applying bleaching agent; Polanight (SDI). Study group specimens were bleached for 21 days, 2 hours a day. The specimens were loaded using a universal testing machine with a crosshead speed of 0.5 mm per minute. The maximum load at specimen failure was recorded and the KIc (MPa. M 0.5) was calculated. Statistical analysis using two-way ANOVA showed a significant relationship between material and time (p< 0.05).Tukey’s test showed that after 24 h of immersion in distilled water, Rok revealed the highest KIc followed by Esthet and Estelite. The bleaching agent significantly improved the fracture toughness values of Esthet while it decreased that of Estelite. The fracture toughness of the resin composites was affected by the bleaching agent and distilled water. In comparison with Rok and Estelite, fracture toughness of Esthet was increased due to aging and application of bleaching agent.

Statement of Problem: The increasing use of smokeless tobacco in the last 15 years has motivated researchers to evaluate its impact on its user’s health. The aim of this study was to determine the frequency of oral lesions related to smokeless tobacco and any possible correlation between the frequency of oral lesions and the amount of usage in patients referred to Zahedan Dental School. A total of 90 (77 male and 13 female) cases, all snuff consumers, were surveyed in this cross sectional study which was accomplished by employing questionnaires. The questionnaire included demographic information, type and amount of smokeless tobacco used and the location where it was placed in the mouth. The completion of the questionnaires was followed by oral clinical examinations of patients. The location of any lesion found in soft tissue, was recorded in questionnaire. The mean age for men and women was 47.7 and 55.61, respectively. A total of 38 cases (29 males, 9 females) were found to have oral lesions. 26 patients were using the snuff one pack per day. The common site of lesions was lower buccal sulcus. From 38 lesions, 32 lesions were found at the site of snuff placement. Most of the lesions were degree 1 and white in color. After taking biopsy from 32 lesions, 26 cases were detected as hyperkeratotic and 6 cases as epithelial dysplasia. This study showed that use of snuff is very common in Zahedan and usage of this material can produce oral lesions. There is not a significant correlation between the frequency of oral lesions and the amount of usage.

Intraosseous mucoepidermoid carcinoma is a rare tumor which affects women more than men and is more common in the mandible. The radiological examination reveals a well-defined unilocular or multilocular radiolucent lesion. This tumor may resemble a glandular odontogenic cyst, particularly in incisional biopsies. The accurate diagnosis of these lesions is imperative because the subsequent treatment of each lesion would be different. The purpose of this study is to report two cases of intraosseous mucoepidermoid carcinoma and explicate the differentiating criteria of this lesion from the glandular odontogenic cyst.