Dental Research Journal
Volume:7 Issue: 2, Mar 2010

Considering the role of T cells in the pathogenesis of periodontitis, the purpose of this study was to compare the amount of IFNγ, IL4 and IL17 in advanced periodontal lesions with healthy gum areas to determine each TH1, TH2 and TH17 cells activity in comparison with each other and finally, to compare the value and the role of humoral, cell mediate and autoimmune responses. In this descriptive analytical study, those with moderate to advanced periodontitis, having pocket with 4 to 7 mm in depth, were randomly selected. After preparing the healthy and affected sample tissues, the amount of the specific antibody in I IFNγ, IL4 and IL17 cytokines were measured using ELISA method and were compared between the two groups. The findings were analyzed using the software and descriptive statistical methods and Pearson correlation statistical analysis (α= 0.05). This study was performed on 37 patients with moderate to severe periodontitis and 22 healthy individuals without any periodontal disease. IL4 and IFNγ levels in the patients with chronic periodontitis compared to those of healthy gingival samples showed a significant reduction (P > 0.05) whereas the amount of IL17 in tissue samples of chronic periodontitis compared to healthy gums had a significant increase (P < 0.05). It appears that in the periodontitis pathogenesis, as well as TH1 and TH2 responses, IL17 causes the host immunological response to the periodontal pathogenesis.

Given the fact that bruxism is a prevalent oral habit among children and a potential destructor of oral tissues, the present study aimed to investigate the relationship between intestinal parasitic infections and bruxism among kindergarten children. Questionnaires were administered among parents of kindergarten children in Isfahan to select 50 children identified by their parents to have the habit of bruxism and 50 without the habit as control group. Informed consent was obtained prior to the investigation. Parents were delivered sampling instruments with proper instructions to collect stool samples from both groups for parasitological tests. The diagnostic parasitological tests involved the direct stool smear, formol-ether concentration, and Scotch tape tests. Comparison for the frequency distribution of intestinal parasitic infections between the two groups was performed using the chi-square test (α = 0.05). Parasitic infections were observed in 19 (11/50 cases and 8/50 controls) children. A statistically significant relationship was observed between infection with pathogenic parasites and bruxism (P < 0.05). Our findings suggest that pathogenic parasites may serve as the cause of initiation of bruxism habits among children.

Dental students constitute a stakeholder group that is able to provide unique information concerning the effectiveness of the dental curriculum. The purpose of this study was to determine students’ perceptions of the learning environment, intellectual climate and teacher student relationships in dental school. This study was conducted among 341 dental students of two dental college of Udaipur, Rajasthan, India. Response rate was 85%. In this study, the dental version of Medical Student Learning Environment Survey has been used. The questionnaires were divided in to 7 subscales like flexibility, student to student interaction, emotional climate, meaningful experience, organization, supportiveness, and breadth of interest. The students were divided in to two groups of preclinical and clinical for the purpose of comparison. The data were analyzed using ANOVA and t-test. The results were statistically analyzed and differentiated in to preclinical and clinical phases. The preclinical and clinical students rated the student to student interaction as the most favorable whereas the lowest score was given to flexibility by both preclinical and clinical students. Preclinical students rated emotional climate as the lowest after flexibility whereas clinical students rated breadth of interest and meaningful experience as the lowest score after flexibility. This study emphasized the areas of improvement in dental school learning environment based on students’ perspective by making these required and much needed changes in the curriculum. Students’ satisfaction with their dental education can be increased.

Chewing-gum may serve as an effective oral hygiene device when brushing may not be possible. The aim of the present study was to evaluate the effect of chewing sugar-free gum twice a day after meals in addition to tooth brushing on dental plaque and interdental debris. Twenty four (12 males and 12 females aged 20-21 years) healthy third-year dental students participated in the study. It was a prospective single blind and non-randomized before and after study. The control group followed tooth brushing habit twice a day plus water rinsing after meals at noon and night for 10 days. The study group followed tooth brushing habit twice a day plus chewing one pellet of sugar-free gum after meals at noon and night for 30 minutes for 3 weeks. Personal hygiene performance index (PHP-M) was used to assess the dental plaque and self-designed interdental debris index for interdental debris. ANOVA, Tukey and ‘t‘ tests were used for data analysis. The level of significance was fixed at α = 0.05. The baseline percentages of cumulative plaque and interdental debris were 63.12% and 76.44%, respectively. There was no significant difference in the plaque scores following either water rinsing (61.73%) or gum chewing (59.44%) after meals, but a statistically significant reduction of 14.18% in interdental debris was observed among those who chewed the gum (p < 0.05). After meal, gum chewing in addition to daily tooth brushing reduced interdental debris, but had no effect on established buccal and lingual dental plaques.

As various implant geometries present different biomechanical behaviors, the purpose of this work was to study stress distribution around tapered and cylindrical threaded implant geometries using three-dimensional finite element stress analysis. Seven implant models were constructed using the CAD system. After digitized models of mandibular section, the crowns were created. They were combined with implant models, which were previously imported into CATIA. The combined solid model was transferred to ABAQOUS to create a finite element meshed model which was later analyzed regarding the highest maximum and minimum principal stresses of bone. For all models, the highest stresses of cortical bone were located at the crystal cortical bone around the implant. Threaded implants, triangular thread form and taper body form showed a higher peak of tensile and compressive stress than non-threaded implants, square thread form and straight body form, respectively. A taper implant with triangular threads, which is doubled in the cervical portion of the body, had a significantly lower peak of tensile and compressive stress in the cortical bone than straight/taper triangular or square threaded implant forms. For the investigation of bone implant interfacial stress, the non-bonded state should be studied too. Confirmative clinical and biological studies are required in order to benefit from the results of this study.

Radiographic examination of TMJ is indicated when there are clinical signs of pathological conditions, mainly bone changes that may influence the diagnosis and treatment planning. The purpose of this study was to evaluate and to compare the validity and diagnostic accuracy of uncorrected and corrected sagittal tomographic images in the detection of simulated mandibular condyle erosions. Simulated lesions were created in 10 dry mandibles using a dental round bur. Using uncorrected and corrected sagittal tomography techniques, mandibular condyles were imaged by a Cranex Tome X-ray unit before and after creating the lesions. The uncorrected and corrected tomography images were examined by two independent observers for absence or presence of a lesion. The accuracy for detecting mandibular condyle lesions was expressed as sensitivity, specificity, and validity values. Differences between the two radiographic modalities were tested by Wilcoxon for paired data tests. Inter-observer agreement was determined by Cohen's Kappa. The sensitivity, specificity and validity were 45%, 85% and 30% in uncorrected sagittal tomographic images, respectively, and 70%, 92.5% and 60% in corrected sagittal tomographic images, respectively. There was a significant statistical difference between the accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions (p=0.016). The inter-observer agreement was slight for uncorrected sagittal tomography and moderate for corrected sagittal tomography. The accuracy of corrected sagittal tomography is significantly higher than that of uncorrected sagittal tomography. Therefore, corrected sagittal tomography seems to be a better modality in detection of mandibular condyle erosions.

Methyl methacrylate (MMA), a widely used monomer in dentistry and medicine has been reported to cause abnormalities or lesions in several organs. Experimental and clinical studies have documented that monomers may cause a wide range of adverse health effects such as irritation to skin, eyes, and mucous membranes, allergic dermatitis, stomatitis, asthma, neuropathy, disturbances of the central nervous system, liver toxicity, and fertility disturbances.

Excessive alveolar bone resorption is commonly found when teeth are extracted. This is a problem in anterior part of mouth because it will result in an unaesthetic pontic on a narrow hollowed out alveolar ridge. Yet, another problem is gingival recession and root exposure in adjacent teeth which represent a therapeutic problem to the clinician.Use of acellular dermal matrix graft is an appropriate solution to obtain root coverage in areas with localized or generalized soft tissue recessions, particularly if the recessions create aesthetic concern or root sensitivity or shallow root caries lesions. This case report describes a surgical technique using acellular dermal matrix graft on a class III ridge defect and Millers grade II gingival recessions.There was a gain in both bucco-lingual and apico-coronal dimensions of the ridge, in both height and width directions, when compared to baseline and after 3 months. Recession was also covered compared to the baseline condition.