JOURNAL OF ISFAHAN DENTAL SCHOOL
Year:2008 | Volume:3 | Issue:4|Papers Count:10

Introduction: Cross infection control is of a great concern and great attention should be paid to it. Dentistry offices and laboratories are predisposed to make and transmit contamination; therefore both dentists and laboratory director shall regard cross infection control policies in order to prevent dental cross contamination between patients and personnel. The aim of this research was to asses the quality of bacterial contamination in fixed restoration in different stage of preparation.Methods and materials: In this descriptive analytical study, samples were obtained from 75 crown and bridges in metal frame work. Bisque and glaze stage and microbial cultures were taken. Information's were statistically analyzed by MC Namara Analysis.Results: From 75 samples, 37 (%49.32) were contaminated. Prevalence of pathogenic and non pathogenic bacteria was as follows: Staphylococcus in 27 cases (%72.97), Bacteriallus 7 in cases  (%18.91), Klebsilla in 2 cases (%15.40), and E-coli in 1 case (%2.72). The difference between this stages was not statistically significant (p value = 0.754).Discussion: Staphylococcus is the most commonly found bacteria in fixed restorations. It may be due to handling restorations without gloves.

Introduction: Incidence of preterm labor (PTL) is 5-10 percent. Odontogenesis is initiated in 6th- 7th week of embryonic life by budding stage and continues until juvenile period. This complex and long standing developmental process is affected by metabolic events, physiologic and pathologic processes, and local, systemic and environmental hazardous factors. This study was aimed to determine association and relationship of preterm labor and developmental defects of enamel and dental caries.Method and Materials: Based on archives of obstetrics and gynecology wards of seven major Isfahan hospitals, 200 children with preterm and term labor were selected. Study groups were considered in equal ratios of gender. Based on WHO criteria, oral and dental health of the children was assessed. The number of decayed, filled and missed teeth and prevalence of developmental defect enamel were recorded. Findings were analyzed statistically by SPSS software using chisquare and t-test and the results were reported by descriptive statistics in figures and tables.Results: The prevalence of developmental defect enamel in preterm and term labor was 72% and 57%, respectively. The difference of prevalence of developmental defect enamel was significant in two groups (p value = 0.026). The mean of caries rate in preterm and term labor were 4.96 ± 3.33 and 5.72 ± 3.68, respectively. The difference of dental caries was not significant.Conclusion: Preterm labor is associated with more prevalence of developmental defect enamel. The difference mean of dental caries is not related to pregnancy length.

Introduction: Centric Relation (CR) is the most important recording procedure of maxillamandibular relation in prosthodontic. We investigated the influence of patient's body position in CR recording by extra-oral tracing method.Materials and Methods: In this analytic cross-sectional study, 18 dentulous subjects were selected randomly. After patient education, the extra-oral tracing device attached to acrylic stents; then the Gothic arch tracing was accomplished in supine, semi supine and upright positions. The CR achieved by bimanual manipulation method was also recorded. Four points were recorded in four transparent sheets; also, the vertical (Y) and horizontal (X) axis were measured for each point. Then the horizontal, anterior- posterior and straight distances of each point to point that achieved by bimanual manipulation were calculated. Data were analyzed using the one-way ANOVA and ttest with the significant level of I = 0.05.Results: There was no significant difference between horizontal distances of points registered in various body positions and of point registered in Dawson method, but with a view to ant-post and direct distance, the point registered in supine and semi supine positions were significantly nearer to Dawson manner, rather than the points registered in upright position. No correlation to sex and age was obtained between distances of registered points in various body positions and registered point in Dawson method.Conclusion: In dentulous subjects, in comparison to upright position, the obtained CR in supine and semi-supine positions by extra oral tracing method had significant similarity to bimanual manipulation.

Introduction: In some studies, ultrasonic scalers could increase the microleakage in teeth restored with tooth colored restorations; in a few others, air polish system caused surface roughness on the tooth colored restoration surfaces. The aim of this research was to compare the effect of air polishing system on microleakage of Z250 Filtek composite and Vitremer glass inomer in cervical restorations.Methods: Seventy two extracted premolar teeth were collected and randomly divided into two equal groups. In all the teeth, standard class V cavities were prepared in cervical regions on the buccal side. Half of the teeth were filled with Z250 Filtek composite and the other half with Vitremer glass inomer. The specimens were thermo cycled. Half of the specimens on each group were subjected to air polish system from 3 mm distance Microscope with 32 magnifications was used for microleakage measurements.Results: Air polish system caused increased microleakage in both groups (p value < 0.01) and Vitremer glass inomer had significantly more leakage than composite 250 Filtek (p value < 0.001). Leakage at the enamel margins was significantly less than at the dentin margin in both two groups, but the difference was only statistically significant for Vitremer glass inomer (p value < 0.05). Discussion: As air polish system application causes increased microleakage of composite 250 Filtek and Vitremer glass inomer, we advise to use it with caution in teeth filled with composites. It is not advised to use air polish system in teeth filled with glass inomer.

Introduction: The aim of this in vitro study was to evaluate the effect of light - activated bleaching on new and aged class V composite - resin restorations.Methods and Materials: 72 freshly extracted premolars were prepared with class V cavities (4 × 2.5 × 1.5 mm) with extension to 1 mm apical to CEJ. Cavities were restored using Single bond and Z100 composite resin. The specimens randomly divided into 6 groups. The samples in groups 2-5 were bleached using in-office bleaching gel and plasma-arc bleaching unit immediately, 7, 30 and 90 days after restoration respectively. Groups 1 and 6 were control groups and did not received bleaching treatment, stored for 1 and 90 days in waters, then evaluated. At the end of each storage period, the samples sealed with nail varnish and immersed in 2% basic fushin, and microleakage was evaluated using 0-3 score scale. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests at 0.95 level of significant.Results: No statistically significant differences between study groups were observed in enamel margins (p value = 0.244). Microleakage was increased significantly in dentinal margin of group 2 (p value = 0.034).Conclusion: Performing plasma-arc bleaching immediately after restoration could increase microleakage of composite- resin restorations in dentinal margins. Immediate light-activated bleaching of the composite-resin restorations might jeopardize marginal integrity of dentinal margins.

Introduction: Different factors can affect the retention of full veneer crowns such as clinical length of crown, diameter of tooth, angle of convergence, type of restoration and the cement. The aim of this study was assessment of the convergence angles of tooth preparations for full coverage crown among dentistry students.Methods and materials: In this observational- cross sectional study, 210 dies from prepared anterior and posterior teeth by under graduate and postgraduate students were randomly selected. In the two groups, the mesiodistal and buccolingual angles of the dies were measured with stereomicroscope and moticam camera and compared with each other. The results were analyzed by t-test via SPSS- 11.5 software.Results: The total average convergence angle was 23.8 ± 8.6 degrees for the preparations performed by undergraduate students and 22.4 ± 9.0 for postgraduate group. The average convergence angle for anterior preparations was 24.4 ± 8.1 degrees in undergraduate group and 20.2 ± 7.7 degrees in postgraduate group and for posterior preparations it was 23.6 ± 8.8 degrees in under graduate group and 24.1 ± 9.6 degrees in other group. Differences in convergence angles of anterior preparations between two groups were significant (p value = 0.02), but for posterior preparations and other preparation were not statistically significant.Conclusion: The total average convergence angle of all preparations and posterior preparations in two groups were the same, But it was significantly greater in anterior preparations prepared by undergraduate students. In any case, the findings were similar to some of previous studies.

Introduction: Dental procedures are usually painful and fearful. Anxiety in the anteroom causes difficulty in dental treatment. Oral medication is one of the best methods for decreasing preoperative anxiety. This study performed for comparison of the effect of oral oxazpam and combination of oxazpam- tramadol on anteroom anxiety in dental ward.Method and Material: In this study, 84 healthy adult patients from surgery ward of Isfahan dental faculty of Isfahan University of Medical Sciences were chosen with random sampling. The patients randomly divided in three groups: oxazpam, oxazpam- tramadol and placebo. Anxiety of patients was measured using 20 score questionnaire DAS-R. Data was analyzed with SPSS software and descriptive statistical analyses.Results: There was no difference in sex and age between patients in the three groups. Anxiety score in oxazpam group was 10.82 ± 3.25, in oxazpam- tramadol group was 11.61 ± 3.29 and in placebo group was 13.29 ± 2.28. Kruskal- Wallis test didn't show any difference in anxiety score between oxazpam and oxazpam- tramadol groups, but anxiety score in placebo group was higher than other two groups.Discussion: In our study, mean anxiety score in oxazpam and oxazpam- tramadol group was 10.82 and 11.61 respectively. Mean of anxiety score in placebo group was 13.29, higher than study groups. This study showed that oxazpam and combination of oxazpam- tramadol can decrease preoperative anxiety in anteroom more effective than placebo.

Regarding the importance of surface roughness of tooth structure and restorative materials on plaque retention, this study was done to evaluate the effect of home and office bleaching agents on surface roughness of microhybrid and nanofilled composite resins.Materials and Methods: Point 4 (kerr, USA) microhybride composite, Premise (Kerr, USA) and Filtek supreme (3M ESPE, USA) nanofilled composites, Opalescence PF (Ultradent, USA) as the home bleaching agent and Opalescence Quisk (Ultradent, USA) as the office bleaching agent were selected. One hundred and fifty samples were divided into 15 groups (n = 10). For each composite, five groups were defined as: control, two weeks home bleaching, 4 weeks home bleaching, one time office bleaching and two times office bleaching with 2 weeks interval. The composites light cured under clear matrix strip and polished with soflex TM (3M ESPE, USA) polishing disks systems. After bleaching with specific protocol, surface roughness of samples was measured with profilometer (SM7 Profile Test, Italy). The data were analyzed with two-way ANOVA statistical test. Surface morphology of samples were analyzed with scanning electron microscopy; SEM (XL30, Philips, Netherlands).Results: There was no significant difference in surface roughness among all groups (p value > 0.05). There were no difference between the surface morphology of control and experimental groups of each composite.Conclusion: The bleaching agents used in this study had no effects on surface roughness of two types of nanofilled composites and one type of microhybrid composite.