Journal of Dentistry, Shiraz University of Medical Sciences
Volume:11 Issue: 4, 2011

Statement of Problem: Verrucous carcinoma (VC) is a rare type of squamous cell carcinoma (SCC). These two lesions have many biological and clinical differences and proper diagnosis of these tumors have has a great influence on the patient's treatment. The purpose of this study was to compare the expression of p53 and Bcl-2 in VC, SCC and pseudoepitheliamatos hyperplasia (PEH).Methods and Material In this study, expressions of p53 and Bcl-2 markers in 20 samples of paraffin blocks of VC, 23 samples of SCC, and 22 samples of PEH were examined by immunohistochemistry method. Immunoreactiv-ity was diagnosed for p53 in the nucleus and for Bcl-2 in the cytoplasm of cells and. Then, the mean of percentage of the expression of p53 and Bcl-2 was compared. The collected data were analyzed, using SPSS Ver. 7.5. For statistical analysis, ANOVA and Tukey tests were used for Bcl-2, and Kruskal-Wallis was used for comparison between of the markers. There was a significant difference in the Average mean of Bcl-2 expression between the lesions which the VC was significantly lower than the others.There was also a significant difference in the average mean of p53 expression between the lesions. T p53 and Bcl-2 are two immunohistochemical markers which can be helpful markers in differential diagnosis of VC and SCC.

Statement of Problems: Amoxicillin–Metronidazole in conjunction with mechanical therapy such as scaling and root planning (SRP) is an effective adjunctive method for treatment of chronic periodontitis. The use of Co–Amoxiclave as a single medical therapy has been of interest because of its similar therapeutic effects as compared with the compounds mentioned above. The aim of this study was to compare the effects of Amoxicillin-Metronidazole and Farmentin (a new compound of Co- Amoxiclave) in treatment of Moderate Chronic Periodontitis. Methods and Material: In this experimental single blind study, 60 patients (30 females and 30 males) with choronic moderate perdontitis and with an average age of 30-50 years old were evaluated. Scalling and root planning (SRP) and oral health instruction (OHI) were done for all the patients. They were divided into three groups. Group one received Farmentin and group two received Amoxicillin–Metronidazole for one week. Group three didnt receive any antibiotic.Periodontical Disease Index (PDI), Gingival Index (GI), Modified Papillary Bleeding Index (MPBI), Plaque index (PLI), and probing packet Depth (PPD) were measured in their first visits, one week after scaling and before taking medicine, 1,3,6 weeks after taking medicine and 2, 3 months later. Finally, all the data were statistically analyzed by Anova and Tukey test. None of the parameters under the study showed a statistically significant difference between groups 1 and 2 (P 0.05). During the treatment GI showed a significant difference between the test and control groups (p <0.05). MPBI in the test and control groups was significantly different one week after scaling and follow ups. There were significant differences between the two test groups and control in PLI, one week after taking medicine. Also, there were significant differences between groups 1 and 3 (p=0.049, p=0.007) and groups 2 and 3 (p =0.044, p =0.028) in the 4 latest follow up for PPD and PDI. Both Farmentin and Amoxicillin-Metronidazole in conjunction with mechanical therapy (SRP) have similar effects in treatment of chronic moderate periodontitis; however, they are more effective than SRP alone.

Statement of Problem: One of the major problems in old composite filling reconstruction is creating powerful bond strength between the existing composite and the new composite filling. Furthermore, complete exchange of the old composite filling may jeopardize the tooth structure. In this situation, repairing the previous composite filling is more practical and the risk of pulp involvement may be decreased. No study has been done on the comparison of G-Bond and other bodings effects with or without silane usage except the manufacturer's claims. The aim of this study was to evaluate the effect of two different bonding agents on the shear bond strength of the existing composite and the new composite filling with or without silane usage.Methods and Material: In this experimental and in vitro study, 50 cylindrical composite blocks were prepared. Ten samples were used as control group in the size of 5×6 mm (one piece composite). The remaining 40 samples as the case groups were made in the size of 5×3 mm. The samples were stored in distilled water at 37oc for 2 weeks. The surface of all the samples were roughened, etched and cleaned. These 40 samples were divided into 4 equal groups based on the bonding procedure and silane usage. The groups were Clearfil S3 bond and silane (group A), Clearfill S3 Bond only (group B), G Bond and silane (group C), and G Bond only (group D). Then, the samples were stored in distilled water for another 2 weeks. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Shear bond strengths were analyzed with one way analysis of ANOVA. Shear bond strength was significantly different in the 5 groups. Shear bond strength in the control group was 34.24 Mega pascal, being significantly higher than that in the other 4 groups. The averages of the shear bond strength, were 25.88, 23.14, 21.19 and 17.20 for group A, B, C and D respectively. The results showed a statistically significant difference between the 4 groups and the control group. The results of this study indicate that composite cohesive strength (control group) had the highest strength, whereas there was no statistical difference among the other groups.

Statement of Problem: Preservation and maintenance of pulpal vitality is the main objective in endodontics. A recently developed material, mineral trioxide aggregate (MTA), is recommended for vital pulp therapy because of its physical characteristics and bioactive properties. Although the majority of these studies have been performed on the teeth with open apices, further evaluation of the teeth with closed apices seems to be necessary. The purpose of this study was to evaluate the pulpal reaction to MTA after pulpotomy in permanent molar teeth with caries.. Methods and Material: In this clinical case series study, 17 permanent molar teeth of 16 patients with a carious exposure were treated, using a partial pulpotomy technique. The age of the patients ranged from 20 to 30 years with an average of 25.2 years. Clinical and radiographic examination revealed a pulpal response within normal limits and normal appearance of the periradicular area respectively. After isolation, caries removal and pulpal exposure, access cavity was prepared using a sterile diamond bur with cooling system. After hemostasis, 2 to 4 mm of MTA (Angelus) paste was placed on the fresh wound. The teeth were restored 5-7 days later with amalgam or composite. The patients were scheduled for follow-up at an interval of 2, 6 and 12 months, and clinical and radiographic findings were established. An overview of the data with respect to the clinical and radiographic findings at 2, 6 and 12 months of follow-up showed 100% success rate. Pulpotomy therapy, if the teeth are appropriately selected and MTA is used in suitable conditions especially when conventional treatment is not possible, gives a chance to the pulp to recover and could be the treatment of choice..In case the treatment fails, retreatment thereafter is possible. Nevertheless, further investigations with more samples are recommended for final judgment.

Statement of Problem: One of the major problems of the all ceramic restorations is their probable fracture against the occlusal force. However, there is not enough information about fracture resistance of all the ceramic crowns in different finishing lines. The aim of present in-vitro study was to compare the effect of two marginal designs (shoulder and chamfer) on the fracture resistance of all ceramic restorations, Inceram.Methods and Material: On an extracted caries–free first maxillary premolar a 50-degree chamfer margin (0.7 mm) was prepared. Ten impressions were taken using a polyvinylsiloxane. The impressions were poured with epoxy resin to fabricate the dies. The same tooth was retrieved and the 50-degree chamfer was converted into a 90-degree shoulder margin (1mm). Ten impressions were prepared and 10 more epoxy resin dies were fabricated. The impressions of each epoxy resin die were taken using polyvinylsiloxane impression material and poured with die stone. Alumina cores with a thicknes of 0.5mm were fabricated on the stone dies in a dental laboratory. The alumina cores were then cemented with panavia on the epoxy resin dies and underwent a fracture test with a universal testing machine. The samples were then investigated regarding the origin of the failue. The statistical analysis was done using T-test. The mean value of the fracture resistance for the chamfer samples was 610.18±58.79 N and that of the shoulder samples was 502.72±105.83 N. The student's T-test revealed a statistically significant difference between the groups (p <0.05). The results of this study indicate a relationship between the marginal design and fracture resistance. A chamfer margin could improve the biomechanical performance of the posterior single crown alumina restorations. This might be due to the strong unity in the chamfer margin.

Statement of Problem: Free surface energy of substrate is an important factor for adhesion. High free surface energy results in increased wetness and better adhesion.

The aim of the present study was to evaluate the effect of different rinsing times after cutting with a suggested coolant on the free surface energy of the dentin.Methods and Material: In this in-vitro experimental study, 75 intact human premolar were randomly assigned into 5 groups: 1) Cut with water coolant, 5 seconds of rinse with water. 2) Cut with water coolant, 5 seconds of rinse with water, etch, rinse. 3) Cut with a suggested coolant (0.5 surfactant/HLB=7), 5 seconds of rinse with water. 4) Cut with a suggested coolant, 10 seconds of rinse with water, and 5) Cut with suggested coolant, 15 seconds of rinse with water. Free surface energy was measured by estimating the contact angle. The statistical analyses were performed using one-way ANOVA and Tukey tests.

The surface energy means (dynes/cm) of groups 1 to 5 were 75.87, 46.00, 74.86, 72.64 and 70.05, respectively. The results of one-way ANOVA showed a significant difference among the five groups (p =0.000). The Tukey test showed that except groups 1 and 3 (p =0.678), there was a significant difference in all the other groups (p <0.05).

Etching reduces the dentin surface energy. The surface free energy of the cut dentin with a surfactant as a coolant and then rinsing with water for 5 seconds is equal to dentin which is not etched. Rinsing for more than 5 seconds (10 or 15 seconds) reduces the dentin surface energy.

Statement of Problem: One of the complications in reconstruction of the primary teeth with stainless steel crowns (SSC) is microleakage at the crown's margins. Luting cement that can seal the margins can reduce the microleakage. This research was performed to compare the ability of four adhesive cements for reducing microleakage at the SSC margins.Methods and Material: In this experimental study, standard preparation was performed on 60 primary molar teeth for SSC restorations. After adjusting SSC, the samples were randomly divided into 5 groups, each containing 12 teeth. Then, the SSCs were cemented in each group with different cements. These groups contained Zincphosphate (Elite, ZP), Polycarboxylate (Durelon, PC), Glass ionomer (Ketac cem, GI), Resin-modified glass ionomer (Rely X luting 2,RMGI), and Resin-modified glass ionomer with bonding agent ((Single Bond,SB). After thermocycling and using dye penetration (methylen blue 1%), the samples were evaluated under a digital microscope. For comparison of the microleakages among the groups, t-test, ANOVA and LSD tests were used. Microleakage in the adhesive cement groups (GIC, RMGIC, RMGIC+BA) was significantly lower than that in the non-adhesive (ZP, PC) groups (p <0.05). Comparison of the cements revealed a statistically significant difference among all the groups (p <0.001). RMGI+SB had the lowest microleakage followed by RMGI, GI, ZP. PC cement showed the greatest microleakage. Adhesive cements were more effective in reducing the microleakage in cementation of SSC than non-adhesive cements. The use of bonding agents with RMGI cement showed more acceptable results in comparison with RMGI cement.

Statement of Problem: Ankylosis of the primary teeth in the mixed dentition leads to dental arch circumference reduction and postpones the eruption of the successor teeth. To the best of our knowledge, there has not been a comprehensive research about tooth ankylosis and its related factors in the city of Mashhad, Iran. The purpose of this study was to determine the prevalence of tooth ankylosis and evaluate its effects among school children in Mashhad.Methods and Material: The experimental sample of this cross-sectional study consists of 1000 six to eleven year old students in seven areas of Mashhad. Stratified cluster sampling was used for the selection. Data were gathered using both clinical and radiography examination, examination of the siblings affected with ankylosis and interviews with parents. The examination methods were inspection, palpation, and auscultation. The data were analyzed by Chi-square, and Kruskal-Wallis tests using SPSS software (V.16). The prevalence of tooth ankylosis in clinical examinations was 8% for the total sample with no significant difference between the two genders. The most frequent ankylosed tooth was the lower first molar (56.7%) (p < 0.001). As to the severity of ankylosis, the moderate form was the most frequent type (55.3%) (p =0.012). In the cases with unilateral ankylosed teeth, the frequency of midline deviation was significantly higher than bilateral cases (p = 0.023). The prevalence of ankylosis was noticeable in children, indicating the importance of careful periodic examination of children by dentists.

Statement of Problem: Because dental restorations are time consuming, dental material manufacturers make an attempt to discover new methods for rapidity and increasing the quality of restorations. With this objective in mind, plasma arc curing devices have been manufactured. This study was done to compare the effect of plasma arc and halogen light curing on the microleakage of class V resin composite. Methods and Material: In this experimental study, on 80 extracted maxillary central teeth, standard class V cavities were prepared with incisal and gingival margins in the enamel and dentin. After etching and bonding, the teeth were randomly divided into two subgroups of 40 and restored with Amelogen composite. In the first group, halogen light curing for 40 seconds was used and in the second one plasma arc curing was used for four seconds. After thermocycling and sealing, the samples were immersed into the 0.5% fuchsine solution for 24 hours and then washed with water and cut. The microleakage was scored by stereomicroscope with 40X magnification. The data were analyzed using Mann-Whitney and Wilcoxon tests. The mean of incisal wall microleakage in the plasma arc group was 1.42±0.98 and in the halogen group it was 0.67±0.02. The gingival margin in the plasma are group showed a mean of 1.75±1.48 and in the halogen group it was found to be 1.67±1.54. There were significant differences in the incisal wall (p =0.0001), but not in the gingival wall (p =0.744). The average rate of microleakage in the gingival and incisal walls in the plasma arc group was 3.17±1.79 and in the halogen group it was 2.76±1.92; there were not any significant differences between the groups (p =0.32). In the restorations with enamel margins halogen light curing and in all composite restorations plasma arc curing are preferred due to the short time of curing.

Statement of Problem: Disease causing factors transferred by the blood are the main job related problems to which the health workers are confronted in medical centers. This is an urgent medical problem which requires appropriate measures to be taken to decrease the transmission as far as possible.. The aim of this study was to investigate the level of dentist's knowledge and practice in Kerman city about the post-exposure prophylaxis of HIV.Methods and Material: This was an analytical, cross-sectional study conducted through questionnaires. The case study consisted of all the dentists in Kerman (140), recruited through convenient sampling method. Data were analyzed using Mann-Whitney u, X2, Kruskal Wallis and Spearman tests in SPSS, version 13.5. In the present study, 103 dentists were enrolled. Their information and knowledge mean score was 2.32±1.2 out of 6. Also, the lowest and highest scores of the participants were 1 and 5, respectively (with the mean value equal to 3). It was found that the dentist's level of knowledge has no significant relationship with age, sex, education, work history and experience of needle stick injuries. Ninty three dentists (90.2%) had educated their staff about the prevention of HIV and 58% of the dentists agreed to treat the patients with positive HIV. The results of the present study showed that the dentist's level of knowledge about post-exposure prophylaxis and HIV is low. Therefore, it seems that it is necessary for dentists to improve their knowledge and performance regarding this issue.

Adenomatoid hyperplasia is a rare lesion of the minor salivary glands characterized by localized swelling that mimics a neoplasm. The pathogenesis of adenomatoid hyperplasia is uncertain. Microscopic examination demonstrates lobules of hyperplastic mucous glands that are close to the mucosal surface.In this article, a case of Adenomatoid hyperplasia in a 57 year old man is reported followed by a discussion on its clinical and histopathological characteristics.

Histiocytosis of the langerhans cell is a rare disorder with unknown etiology and a spectrum of disorders characterized by proliferation of the histiocyte-like cells. It presents as Eosinophilic granuloma, Hand-schuller Christian disease, and Letter-siwe disease. The incidence rate is 2.1 in 200.000 child per year.Case Report: The patient was a 3.5 year old male child reffered with swelling of the gingival and hypermobility of the deciduous molar teeth.The diagnostic procedures until the final diagnosis of langerhance cell histiocytosis and treatment of this case are reported. Oral lesions could be the first manifestion of histiocytosis of the langerhans cell, of which the dentists should be aware. The early diagnosis is so important in treatment and survival of the patient.