JOURNAL OF ISFAHAN DENTAL SCHOOL
Year:2009 | Volume:5 | Issue:2|Papers Count:15

Methods and materials: 45 premolar healthy teeth mounted in cold acryl were provided. The teeth were sectioned vertically below the enamel and were divided into 3 groups of 15 teeth. Group 1 were etched by Ultradent phosphoric acid for 15 seconds and then washed with pure water and air for 10 seconds. Group 2 were etched by Kimia phosphoric acid for 20 seconds and then washed with pure water and air for 15 seconds. Group 3 were etched by MTAD for 3 minutes and then washed with water for 30 seconds. All of the samples were bonded using single bond (3M-USA); and Z100 composite (3M-USA) were cured on the dentin. All samples were placed in thermo cycle, under 500 cycle period in temperature of 5-55°C and then placed in incubator apparatus for 24 hours, to reach mouth environment. The samples were examined by tensile bond strength test with Instrone apparatus and the data were analyzed by one way ANOVA and Duncan statistical test.Results: The difference between group 2 and groups 1 and 3 was meaningful but the difference between groups 1 and 3 was not. Discussion: The bond strength made by Kimia phosphoric acid is less than the one which was made by Ultradent phosphoric acid and MTAD. It seems that because of exciting citric acid which can remove the smear layer and external layer of calcium in dentin, MTAD can make higher bond strength in the same range as Ultradent phosphoric acid, as it can be deeply infiltrated in dentin and can wash easily after use.

Introduction: Orthodontic diagnosis and treatment plans always require radiographic investigation. The investigation mostly used is lateral cephalometry. Reliable measurement of individual gonial angle is very difficult, because of the superimposed images appearing on the lateral cephalogerams. This disadvantage is not encountered in panoramic radiography. The aim of this study was to evaluate the potential of panoramic radiograph to accurately measure gonial angle.Materials & Methods: In this cross- sectional study, standard panoramic and lateral cephalometry radiographs were taken for 281 patients by mean age of 9-10 years. Gonial angle from panoramic and lateral cephalometry radiographs was measured. The measurements were analyzed by paired student t- test.Results: Paired t- test was performed to check for similarity between the measurements. No significant differences were found between the gonial angle when comparing panoramic and lateral cephalometry radiographs (p value > 0.05); also no significant differences between right and left gonial angle of individuals were found (p value > 0.05).Conclusion: Measurement of gonial angle in right and left sections of panoramic radiograph didn't show any differences statistically. That was also the case in panoramic in comparison with lateral cephalometric radiograph. Panoramic radiograph is a useful tool for the measurement of gonial angle, which is an indicator of mandibular growth direction.

Introduction: The aim of this study was to determine the prevalence of enamel defects in primary dentition of the term and preterm infants.Method and materials: In this historical cohort study, enamel defects (enamel hypoplasia and opacities) were evaluated and determined in 137 children (90 term, 47 preterm). Indeed, some data about weight, systemic diseases and medicine consumption in mothers and children and problems during delivery were achieved. Data were analyzed by chi-square test using SPSS software.Results: The prevalence of enamel defects of any type among these children was 27.7 percent, only hypoplasia 14.9 percent, and only opacities 14.9 percent. Enamel hypoplasia was more frequent in upper central incisors (14.9%) and lower first molars (10.6%). The prevalence of hypoplasia and opacities were more frequent in preterm children but results of χ² test did not show any significant difference. Breech presentation, infantile respiratory distress syndrome and hypoxia during delivery were more frequent in preterm children (P = 0.0001).Conclusion: This study showed that there is no significant difference in prevalence of enamel defects in preterm infants in comparison to terms.

Introduction: The aim of this study was to determine the prevalence of enamel defects in primary dentition of the term and preterm infants.Method and materials: In this historical cohort study, enamel defects (enamel hypoplasia and opacities) were evaluated and determined in 137 children (90 term, 47 preterm). Indeed, some data about weight, systemic diseases and medicine consumption in mothers and children and problems during delivery were achieved. Data were analyzed by chi-square test using SPSS software.Results: The prevalence of enamel defects of any type among these children was 27.7 percent, only hypoplasia 14.9 percent, and only opacities 14.9 percent. Enamel hypoplasia was more frequent in upper central incisors (14.9%) and lower first molars (10.6%). The prevalence of hypoplasia and opacities were more frequent in preterm children but results of c² test did not show any significant difference. Breech presentation, infantile respiratory distress syndrome and hypoxia during delivery were more frequent in preterm children (P = 0.0001).Conclusion: This study showed that there is no significant difference in prevalence of enamel defects in preterm infants in comparison to terms.

Introduction: Use of Community Periodontal Index of Treatment Needs (CPITN) and Decayed, Missing and Filled Teeth (DMFT) Index provides a picture of oral health status, which is essential for national oral health policy- making and specific interventions. The aim of this study was to assess the oral health status and treatment needs of Kermanian adult population.Materials and Methods: A multi-stratified sample was used to survey 154 adults aged 35-44 years. Data were collected by a questionnaire and standardized oral health exam according to WHO methodology for caries criteria and periodontal status. The data were analyzed by SPSS software, using c2 and t- student tests.Results: The mean DMFT was 10.88 ± 6.47. 0.6% had healthy periodontium. 3.9% had removable prothesis. 66% brushed their teeth at least one time dily. 5.8% regularly used dental floss. Dental health behavior, gender, educational level, occupation were not significantly associated with DMFT index. There was significant correlation between dental health behavior and CPITN index. There was no significant correlation between dental health behavior and DMFT index.Conclusion: The present study indicates that there are high prevalence dental caries and periodontal diseases in this population, and is far away from the WHO goals for the year 2010.

Introduction: The aim of this study was to determine the effect of antioxidant application on sealing ability of composite resin restorations. Materials and Methods: In this in vitro and interventional study, seventy sound maxillary incisors were divided into seven groups (n = 10). After canal cleaning and Glass ionomer placement in the canal orifices, the teeth in the first to sixth groups were bleached with 10% carbamide peroxide for eight hours daily once a week. No treatment, application of 10% sodium ascorbate gel for 3 hours, application of 10% sodium ascorbate gel for 20 minutes, application of innovate gel for 3 hours, application of innovate gel for 20 minutes and at last, two weeks delay before restoration were done in first to sixth groups respectively. Access cavities in seventh group (control) were just restored, doing nothing else. In all groups, access cavities were restored with Single Bond and Z100 composite resin. After 1000 thermo- cycling, leakage was evaluated by electrochemical and dye penetration methods. Data were analyzed by ANOVA, Tukey multiple comparisons, Kruskal-Wallis, Mann- Whitney and Spearman's tests (a = 0.05). Results: The four and first groups respectively presented least and highest values of micro- leakage than other groups in two techniques. The correlation between the electrochemical and staining data was significant (p value < 0.05) for some groups of test specimens.  Conclusion: After non- vital bleaching, application of innovate gel is a new and effective way in microleakage reduction.

Introduction: The aim of the present study was to cephalometric evaluation of facial soft tissue facial profile for 16-21 years old students of Kerman with normal occlusion.Methods and Materials: In this cross-sectional study, we utilized 59 lateral cephalometric radiographs of 30 girls and 29 boys with mean age of 17.1 years and normal occlusion from Kerman department of orthodontics. Four angular and 10 linear measurements from Holdaway, Ricketts and Subtenly analyses were used to evaluate soft tissue profile. Mean values were utilized to compare girls and boys with each other and with similar studies by t-test using SPSS 12 (a = 0.05).Results: In comparison of girls with boys, soft tissue facial angle, no to H-line and upper lip to E-line were significantly increased in Kermanian girls compared with Kermanian boys; while in boys, upper lip thickness and inferior sulcus to H-line were larger (p<0.05).When comparing with Holdaway soft tissue norms,6 values in boys and 5 values in girls were significantly different. In addition, position of lips and facial convexity showed significant difference with Ricketts and Subtenly norms.Conclusion: Kermanian boys differ from Kermanian girls in an increased lip thickness and more retruded position of chin. In comparison with Holdaway norms, Kermanians have more convex face and thicker chin.