Journal of Dental Medicine
Year:2008 | Volume:21 | Issue:1 (54)|Papers Count:13

Back ground and Aim: Several materials have been introduced for retrograde fillings, pulp capping and sealing root perforations, but their biological effect on vital tissues and cells is not clear. The purpose of this study was to evaluate the reaction of human periodontal ligament fibroblasts to four root canal filling materials: Pro Root MTA, Root MTA, Portland cement and amalgam.Materials and Methods: In this experimental study, impacted or semi impacted third molar teeth were extracted in aseptic conditions and tissues around the roots were used to obtain fibroblast cell line. After proliferation, cells were cultured in chamber slides and extracts of materials were added to wells. Fibronectin, type I collagen and TGF-b expression were measured by immunocytochemistry method. Data were analyzed by SPSS 11.0 using one way ANOVA and Tukey test. P<0.05 was considered as the limit of significance.Results: Collagen I expression was higher in Pro Root MTA group after 24 hours (p<0.05) and in Portland cement group and positive controls after 48 hours. Portland cement group showed the highest expression of collagen after 1 week. There was no significant difference in fibronectin expression after 24 hours. After 1 week the highest expression of fibronectin was seen in Portland cement, Root MTA and Pro Root MTA groups. TGF-b expression was higher in amalgam, Root MTA and Pro Root MTA specimens after 24 hours and was the highest in Pro Root MTA group after 48 hours.Conclusion: Based on the results of this study, Portland cement and Root MTA are comparable with Pro Root MTA and better than amalgam regarding their effects on human periodontal ligament fibroblasts.

Background and Aim: Application of varnish and dentin bonding agents can effectively reduce microleakage under amalgam restorations. Also rebonding may show some effects on microleakage and its complications. The aim of this study was to evaluate the effect of liner/ adhesives on microleakage of Class V amalgam restoration with or without rebonding.Materials and Methods: In this in vitro study Class V cavities were prepared on sixty sound human maxillary premolars with the gingival floor 1mm below the CEJ. Cases were divided into six groups of ten teeth each. Specimens in group 1 and 2 were lined with Copalite and Scotchbond Multi-Purpose (SBMP) respectively. In the third group (control) no liner was applied. The teeth were then restored with spherical amalgam. Specimens in group 4 to 6 received the same treatments but after filling, the interfaces of restorations and teeth were etched with 37% phosphoric acid gel, rinsed and dried. Adhesive resin of SBMP was applied over amalgam and tooth margins and polymerized (rebonding). Specimens were thermocycled, exposed to dye and sectioned. Microleakage was graded (0-3) using a stereomicroscope at X40 magnification. Data were analyzed with Kruskal-Wallis, Mann-Whitney and Wilcoxon pair wise statistical tests. P<0.05 was considered as the limit of significance.Results: The groups lined with SBMP showed the lowest and the groups without liner the highest microleakage (p= 0.001). Significant difference was observed in microleakage mean rank of enamel and dentin margins (p=0.048). Rebonding with resin did not improve the seal (p> 0.05).Conclusion: Based on the results of this study, total etch adhesive system had significant effect on microleakage of Class V amalgam restorations especially in cervical margin. Rebonding did not show a significant effect on microleakage.

Background and Aim: The use of proper temporary restorative materials between appointments is critical in successful root canal treatment. The purpose of this study was to compare the coronal microleakage of four temporary restorative materials including Zonalin, Zamherir, Coltosol and IRM.Materials and Methods: In this in vitro study, standard access cavities were prepared in 120 intact extracted maxillary and mandibular human first molars. Canal preparation was carried out by the step-back technique, and obturation was performed with gutta-percha and AH26 sealer using the lateral condensation technique. Teeth were randomly divided into 4 experimental groups of 25 teeth each and two positive and negative control groups, each containing 10 teeth. In each experimental group the access cavity was restored with one of the tested materials (Zamherir, Zonalin, IRM and Coltosol). In the negative control group the access cavity was filled entirely with sticky wax and in the positive control group no restorative material was applied. Dye penetration technique was used to evaluate microleakage which was measured under a stereomicroscope. Data were analyzed with one way ANOVA and post hoc Tukey tests. P<0.05 was considered as the limit of significance.Results: Dye penetration was observed in all groups. Zonalin and Coltosol had the highest and the lowest dye penetration respectively, with a statistically significant difference (p<0.001). There was no significant difference in dye penetration between IRM, and either Coltosol or Zamherir (p>0.05). Conclusion: The results of this study showed that using Coltosol as a temporary restorative material can provide a better coronal seal in endodontic treatments.

Background and Aim: Accurate bone measurements are essential to determine the optimal size and length of dental implants. The magnification factor of radiographic images may vary with the imaging technique used. The purpose of this study was to compare the accuracy of linear tomography and panoramic radiography in vertical measurements, as well as the accuracy of linear tomography in mandibular width estimation.Materials and Methods: In this test evaluation study, the vertical distances between the crest and the superior border of the inferior alveolar canal, marked with a metal ball, was measured by linear tomography and panoramic radiography in 23 sites of four dry mandible bones. Also the mandibular width was measured at the same sites. Then, the bones were sectioned through the marked spots and the radiographic measurements were compared with actual values.Results: The vertical magnification factor in tomograms and panoramic radiographs was 1.79 (SD=0.17) and 1.69 (SD=0.23), respectively. The horizontal magnification of tomograms was 1.47 (SD=0.17). A significant correlation was found between the linear tomographic and actual values, regarding vertical dimensions (p<0.001, r=0.968) and width (p<0.001, r=0.813). The correlation was significant but lower in panoramic radiographs (p<0.001, r=0.795). Applying the magnification values suggested by the manufacturer, the mean difference of vertical measurements between the tomographic sections was 2.5 mm (SD=3.4) but 3.8 mm (SD=1.65) in panoramic radiographs. The mean of absolute difference in mandibular width between the tomographic sections and reality was 0.3mm (SD=1.13). In the linear tomograms, 4.3% of vertical and 56.5% of the width measurements were in the ±1mm error limit. Only 4.3% of the vertical measurements were within this range in the panthomographs. The linear regression equation between the actual values and those obtained by radiography in vertical dimensions showed that 87.5% of tomograms and 51.8% of panoramic were located in the ±1 mm error limit.Conclusion: Based on the results of this study, the linear tomography is more accurate than panoramic radiography in mandibular height estimation. The accuracy of linear tomography in width estimation is within acceptable limits.

Background and Aim: Oral health is a sign of overall health. Sometimes fear of dental office deprives patients from receiving proper care. This problem decreases the self-esteem of dentists and can also reduce health indices. Understanding anxiety factors may help solve this problem. The purpose of this study was to assess anxiety in patients undergoing treatment in dental offices in the city of Hamedan.Materials and Methods: In this analytic cross sectional study patients above 9 years old and referred to general dental offices in Hamedan were randomly selected and surveyed with questionnaires in two stages. The first questionnaire included 17 standard items based on Dental Anxiety Scale (DAS) and screened anxious patients. Then 400 anxious patients were evaluated with a questionnaire of 64 items based on Corah scale. Data were analyzed by SPSS 13 with multivariate analysis of variance. P<0.05 was considered as the level of significance.Results: Factors related to dental office environment with 31.1%, those related to personal imaginations with 19.4% and factor concerning office management and dental treatment each with 19.1% frequency showed to be most related to anxiety in patients. Improper rest-rooms (46.3%), blood stains in the environment (44.5%) and dirty dentist's gowns (43.8%) were reported to be the most prominent environmental factors. Among the factors originated from personal imaginations, the risk of disease transmission was accounted for the most justifiable source of anxiety (67.3%). Regarding factors concerning office management, dentist’s nervous behavior (47.8%) and his carelessness to the patient (46.8%) were considered as the most significant anxiety sources. Extraction, injection and root canal therapy (48.3%, 44.5%, 44.3%) were the treatment related factors of higher importance respectively. Previous painful treatment experience (47.3%) and poor oral hygiene of the dentist (34.5%) were reported to be among the other justifiable anxiety sources. In all mentioned situations, variations in anxiety factors were significantly higher in women.Conclusion: This study showed that the main cause of anxiety in patients undergoing treatment in dental offices in Hamedan is their personal imagination which is by far more obvious in women than men.

Background and Aim: Diagnosis of occlusal caries in early stages is more difficult than other types, and needs practical proficiency and accuracy as well as application of advanced and modern equipments. The aim of this study was to evaluate the variations among dentists in diagnosis of occlusal caries.Materials and Methods: In this descriptive cross-sectional study, 6 permanent first molar teeth of 8-10 years old children with occlusal caries of 1, 2 and 3 degrees were selected (Espelid method). Color photographs and bitewing radiographs of teeth were displayed on computer monitor and 157 general dentists were asked to determine the existence and depth of caries. Data were analyzed using SPSS software and chi-square test. P<0.05 was considered as the level of significance.Results: 94% of dentists did not diagnose any lesion in grade I caries.3.8% reported enamel caries (correct diagnosis) and 1.9% reported dentin caries. In grade II caries, 15.7% of dentists could not diagnose any caries, 60.7% recognized the caries at the level of enamel (correct diagnosis), and 22.31% reported the dentin level, and 1.3% reported pulp exposures.7% of dentists could not diagnose any caries in grade III, while 27.2% recognized lesions at enamel and 58.9% at dentin level (correct diagnosis), 6.1% of dentists reported pulp exposures and 0.3% did not respond. Female dentists showed significantly higher correct diagnosis compared to males (p=0.013).Conclusion: Based on the results of this study, despite considerable variations among general dentists in diagnosis of occlusal caries, the total accuracy was acceptable.

Background and Aim: Because of polymerization shrinkage and high viscosity of posterior composites, there are some difficulties in using them in posterior restorations. Several methods have been represented to reduce the effect of shrinkage. The aim of this study was to investigate the effect of curing flowable composites under condensable ones in adaptation and microleakage reduction of posterior composite restorations.Materials and Methods: In this experimental in vitro study, forty class II MO cavities were prepared on extracted intact molar and premolar human teeth. Gingival margins were placed 1 mm apical to CEJ. The teeth were divided into two groups. In group 1, flowable composite (Filek Flow, 3M, ESPE, USA) with 0.5-1 mm thickness was applied and cured following application of bonding agent (Single Bond, 3M, ESPE, USA). The rest of the cavity was filled by condensable composite (p60, 3M, ESPE, USA). In group 2 the flowable composite was not cured, and the condensable composite was applied in two increments. After light curing of composites, all the specimens were thermocycled and then immersed in 0.3% basic fuschin. Specimens were sectioned and evaluated for degree of dye penetration under a stereomicroscope. Data were analyzed by Mann-Whitney test with p<0.05 as the level of significance.Results:. There was no significant difference between the two studied groups regarding microleakage. Conclusion: Based on the results of this study, neither cured nor uncured flowable composite under condensable composite can omit microleakage in posterior composite restorations.

Background and Aim: Furcation defects are one of the most challenging problems in periodontal therapy. Regenerative treatment significantly improves the prognosis of the involved teeth. The aim of this study was to compare Bio-Oss plus 10% collagen in combination with either a bioabsorbable collagen barrier (BO/GTR), or coronally advanced flap (BO/CF), in treating human mandibular class II furcation defects.Materials and Methods: This clinical trial included 10 patients with 10 pairs of similar periodontal defects. Each defect was randomly assigned to treatment with BO/CF or BO/GTR. Following basic therapy, baseline measurements were recorded including probing pocket depth (PPD),closed horizontal probing depth (CHPD), clinical attachment level (CAL), and gingival margin position (CEJ-GM), together with plaque and gingival indices. Hard tissue measurements were performed during surgery to determine alveolar crestal height (CEJAC), and vertical and horizontal open probing depth (OVPD, OHPD).After 6 months, all sites were re-entered and soft and hard tissue measurements were recorded.Results: Both surgical procedures significantly reduced probing depth and improved clinical attachment levels, with no significant difference between groups. Gingival margin position (CEJ-GM), was improved in the BO/CF group (0.66±0.51 mm, p<0.05), but not statistically different from BO/GTR group in which remained relatively constant (0.00±0.81 mm). Vertical defect resolution was significant in each groups (BO/CF:3.17±1.47 mm, BO/GTR:3.33±0.51mm). Horizontal defect resolution was also significant with either procedure (BO/CF:3.67±1.31 mm, BO/GTR:3.80±1.83 mm), with no statistically significant difference between groups. Data were analyzed with wilcoxon and Mann-Whitney tests with p<0.05 as the level of significance.Conclusion: Based on the results of this study, treatment of mandibular class II furcation defects with both procedures resulted in statistically significant improvement in open and closed probing measurements, with no significant difference between treatment groups. In BO/CF group there was an additional improvement in gingival recession (CEJ-GM) measurement, which could be attributed to applying crown-attached sutures by the use of orthodontic brackets.

Background and Aim: A single nucleotide polymorphism at codon 72 of the p53 gene alters the p53 protein structure and affects its activity. This polymorphism depends on geographic regions and race. Also its association with some cancers has been reported. The aim of this study was to investigate this polymorphism in well differentiated oral SCC and normal population in the city of Isfahan.Materials and Methods: In this case-control study, 20 paraffin blocks of non metastatic and well differentiated oral SCC were selected from the archive of oral pathology department of dental school between 2001 and 2005. 20 whole blood samples from normal people were considered as control group. After DNA extraction, p53 codon 72 polymorphism was determined by polymerase chain reaction (PCR) technique using specific primers of Arg and Pro and agarose gel electrophoresis. Data were analyzed by Fisher's exact test with p<0.05 as the level of significance.Results: The prevalence of Arg/Arg , Arg/Pro and Pro/Pro genotypes in case group were 45%,45% and 10% respectively compared to 45%,50% and 5% in controls. There was no statistical significant difference in p53 codon 72 genotypes distribution between case and control groups.Conclusion: Based on the results of this study, p53 polymorphism could not be considered as a genetic predisposing factor for oral SCC development in Isfahan.

Background and Aim: According to infection possibility in high risk patients, assessment of microbial contamination in water sources utilized at medico-dental units has become a recent concern. The purpose of this study was to evaluate the microbial contamination in dental units waterlines at the department of operative dentistry, Tehran university of medical sciences in the year 2006.Materials and Methods: In this cross-sectional study, six dental units in the department of operative dentistry were selected to assess microbial contamination in water sources. Samples were taken on Saturdays (the first working day in a week) and in the midweek, 64 and 16 hours respectively after turning the units off. Moreover, for investigating the effect of flushing, sampling was done at 30, 60, 90 and 120 seconds after flushing and were taken from three parts of each unit including air/water syringe, turbine handpiece and also cup filler water. Samples were transported in closed sterile containers to microbiology laboratory of the school pharmacy. Data were analyzed by Kruskal-Wallis and Dunn tests with p<0.05 as the level of significance. Results: E.coli was isolated from contaminated samples. Contamination decreased by flushing. In midweek after 90 seconds flushing, water contamination disappeared. On Saturdays 2 minutes flushing decreased contamination to lower that 200 cfu/ml (the rate recommended by ADA). Samples taken from turbine handpieces showed significantly higher contamination rate compared to air/water syringe and cup filler water (p<0.001).Conclusion: According to the results of this study, dental units waterlines showed bacterial contamination which was eliminated after 120 seconds of flushing.