Journal of Isfahan Dental School
Year:2006 | Volume:2 | Issue:2|Papers Count:17

Introduction: The effect of apical patency on apical seal is very important in canal preparation. The effect of apical Patency on seal of this area was evaluated in this study.Methods and Materials: In this experimental in vitro study, 90 intact single rooted mature human teeth were cut at CEJ level and were divided in two test groups of 40 teeth and two control groups of 5 teeth. Canal preparation was done by step back technique; without Patency file in group 1 and with Patency file in group 2. Then the canals were obturated by lateral condensation. No instrumentation or obturation was done on control groups. The root surfaces of test groups and positive control group were covered with one layer of adhesive wax and two layers of nail varnish except for apical 2mm. Then they were placed in black ink at 37oc in an incubator for 5 days. Thereafter the roots were split into halves and leakage of dye was measured by a stereomicroscope. The data was analyzed by t-student test.Results: Mean dye penetration was 10.125 mm in group 1 and 6, 3 mm in group 2. This difference was statistic-cally significant.Conclusion: Apical seal could be increased with the maintenance of apical Patency during canal preparation.

Introduction: Some times inferior mandibular nerve block anesthesia causes postoperative lip and tongue biting trauma. However, an infiltration injection with a limited anesthetized area has less complication. The aim of present study is to compare the two techniques (block and infiltration) for class I restorative treatment in primary second molars.Methods and Materials: Fourty children between 5-8 years old having bilateral calss I caries lesions on mandibular primary second molars were selected. Bite-wing radiography was used to exclude proximal caries before operation. Operation was made by first using infiltration technique on one side and using block technique on the other side 72 hours later. Standard block injection technique was performed. Infiltration technique consisted of injecting half of a cartridge in the bottom of vestibule between roots of the tooth and injection of 2 drops of anesthetic in mesial and distal papillae after 5 minutes. Pain was assessed using SEM (Sound, Eyes, Motor) scale by an observer who did not know which technique was used. SEM scale is a reliable and easy to administer for assessment of pain.Results: Pain during operation for both techniques, scored by SEM, was compared and there was no significant difference between block and infiltration techniques.Conclusion: Results show, according to less density of bone in buccal plate and less need to a profound anesthesia for minor restorative treatment, infiltration rechnique can be used instead of block injection in mandibular primary molars in 5-8 years children.

Introduction: The Significant Caries (SiC) has been defined to determine dental caries for different societies by Word Health Organization. The goal of present study was to evaluate Sic in 12-year-old students in city of Isfahan and make a comparison with dental caries risk factors.Methods and Materials: This was a descriptive cross sectional study. Three hundred and fourty students, 12-year-old from Isfahan city were examined according to SiC Index by means of mirror and explorer. Risk factors and decay were evaluated and recorded in separate check lists. Findings were analyzed by Chi-square and SPSS software.Results: The mean DMFT for all students were 2.4 and SiC Index was 4.6, which were directly related to factors such as regular brushing, parents’ educational level, mothers’ occupation families' income, consumption of sweets, number of children in the family.Conclusion: SiC Index in 12-year-old students in Esfahan city was far from ideal SiC Index determined by World Health Organization which is 3. Therefore more attention to this group of student is recommended.

Introduction: Coronal microleakage is the major cause of failure of root canal treatments. The purpose of this study was to evaluate the sealing ability of white MTA, C&B Metabond and cavit against coronal microleakage of Enterococcus faecalis for four months.Methods and Materials: Ninety extracted single–rooted human teeth were selected. Root canal instrument-tation and abturation with gutta-percha was performed. The teeth were randomly divided into four groups of 20 teeth each, plus two control groups consisting of 5 teeth. Three millimeters of gutta-parcha was removed from the coronal aspect of the root canals in the groups I, II, III and replaced with C&B Metabond, cavit and white MTA, respectively. The teeth in group IV did not receive an intraorifice barrier. The external surface of each root, except the apical region, was covered with two layers of nail varnish. All teeth were inserted in the designed system for this experiment. The whole system was sterilized and then transferred in a BHI culture. A fresh solution of E. faecials was injected in to the system every 3 days. The samples were evaluated daily for 120 days and the time of culture contamination with E. faecalis was registered in each case. Statistical tests of Variance and Duncan were used to analyze the results.Results: All the samples in positive control group were infected after 24 hours. None of the negative control samples were infected after 120 days. Group I (C&B Metabond) and group II (cavit) had no significant difference with group III (White MTA). But groups I, II was significantly different from group IV (without barrier). Group III wasn’t significantly different with group IV.Conclusion: The obturated root canals that received a C&B Metabond or cavit orifice plug leaked significantly less than the obturated, unsealed group. Therefore, to prevent coronal microleakage this material can be recommended as a intraorifice barrier before restorative treatment is initiated.

Introduction: The purpose of this in vitro study was to investigate coronal microleakage in anterior weakend teeth after root canal therapy, reinforced with different tooth-coloured material and FRC post.Methods and Materials: A total 48 extracted intact central incisors were randomly divided into four experimental groups (n=12). All specimens were endodontically treated using lateral condensation and crowns were totally removed from 2mm of CEJ and were over flared to simulate weakened teeth . Control group (group I) was restored only with gutta percha .In other groups root canal walls were prepared (etching, washing and gentle drying, bonding) and the surface of the posts were cleaned with alcohol and after that covered with bonding agent and then light  polymerized for 40 seconds. Finally post cementation was done during reinforcing of weakened root canal walls with packable composite in group II, self-cure composite in group III and dual cure composite in group IV. All specimens were thermocycled for 500 cycles between 5oc and 55oc0 with a dowel time of 20 seconds before immersion in dye. Then all specimens were sealed with sticky wax and coated with two layer of nail polish & then they were placed in 0.5% fuschine for 24 hours at room temperature and were sectioned longitudinally from the center of post with tooth cutter. Dye penetration in both sections of each tooth were evaluated using a stereomicroscope equipped with digital camera at original magnification of 32× and microleakage recorded in mm. One-way analysis of variances (ANOVA) and least square difference were used for statistical analysis.Result: The control group showed the maximum microleakage and the minimum was related to the third group .There was a significant difference among the average microleakage of all groups.Conclusion: Combination of FRC post and tooth-coloured materials did reinforce structurally compromised root and decreased microleakage and also the microleakage of root/bonding material is more than post/tooth-colored material. Microleakge in selfcure Group because of its polymerization was the least.

Introduction: The diagnosis of the origin of the lesions is one of the basic problems in Endo-Perio lesions. In order to prevent unnecessary and harmful treatment, the accurate diagnosis must be developed. The aim of this study was to evaluate the effect of advanced periodontal diseases on pulp tissue.Methods and materials: In this experimental study, fourty two anterior teeth were extracted from 22 patients referred to dental clinic of Isfahan university with advanced periodontal disease and 5 intact teeth as control were sectioned immediately after extraction. Teeth were fixed in 10% formalin solution. They were decalcified with Nitric Acid 10% and finally two histopathologic sections were prepared and evaluated. The results were statistically analyzed by Fisher’s exact test.Results: From total of 42 teeth; 13 teeth had normal pulp (30.95%), and the other 29 teeth (69.05%) had pulpal problem. The control group showed 100% normal results. Statistical analysis of the results showed significant difference between two groups.Conclusion: Under the limitations of the present study it was concluded that periodontal disease can develop inflammatory lesions, atrophic and degenerative changes in pulp.

Introduction: Maxillofacial region is one of the most complex regions in the body and radiographic imag-ing of this region is difficult because of clinical situation and patient’s cooperation. Aim of this study was to evaluate efficiency of waters as a preliminary radiography for diagnosis of midface fractures.Methods and Materials: This was an experimental, cross-sectional and prospective study. In this investigation clinical examination performed and the number of midface fractures estimated in the patients visiting Al-Zahra medical center and also waters and CT Scan performed to determine the number of fractures. Fried-man test was used for comparison the mean of three dependent groups.Results: Among 20 evaluated patients the mean number of fractures were: CT Scan (5.95), Waters (4.6) and in clinical examination (2.45). Friedman statistical analysis showed significant differences between three groups.Conclusion: According to the results CT Scan showed the most and clinical examination the least number of fractures. Difference was much higher between clinical examination and CT Scan whereas difference between CT Scan and Waters was less. Waters view is useful for evaluation of midface fractures and is a convenient X-ray for patients who are being visited for the first time.

Introduction: Sexual determination is one of the important aspects of forensic medicine. The Iranian population is composed of populations from different regions mixed with each other that created a rich gene pool which is composed of genes from the Turkish, Caucasus, Arabs, Indians and Kurdish populations. The purpose of this study was to analyze dental dimensions and sexual variation in Iranians and develop forensic techniquesMethods and Materials: This descriptive study is composed of 100 stone casts of Islamic Azad University dental students from Iranian population of either sex ranging age from 18 to 24 years. Bucco-lingual breadths from 14 teeth (I1 through M2 of the maxilla and mandible) are taken from the left side and analyzed using the discriminant function statistics.Results: Results of the study revealed that males exceeded females significantly in dimensions Stepwise discriminant function statistics suggested that upper M2 and lower C are the most contributory teeth to the function. Overall accuracy of sex diagnosis ranged from 64 to 82 percent for women and 60 to 76 percent for men.Conclusion: While dental difference between the sexes in Iranian population has been found highly dimorphic, but because in Iranian, the accuracy of this classification remained low at about 74 percent this methods can be used as an alternative with other sex determination methods.