مجله تحقیق در علوم دندانپزشکی
سال نهم شماره 1 (پیاپی 31، بهار 1391)

The aim of this study was to clinically evaluate the use of Enamel matrix protein derivative(EMD) combined with the coronally positioned flap (CPF) to treat gingival recession compared to the subepithelial connective tissue graft (CTG). In this clinical trial study, thirteen patients each with two or more similar bilateral Miller clI or II) gingival recession(40 recessions) were randomly assigned to the test (EMD+CPF) or control group(CTG). Recession depth(RD), Recession width(RW), probing depth(PD), keratinized gingiva(KG), plaque index(PLI) were recorded at baseline and at 1,3,6 months after treatment. Results were analyzed by Kolmogrov-Smirnov, Wilcoxon,Friedman, Paired-samples T Test. The average percentages of root coverage for control and test groups were 63.3% and 55% respectively. Both groups showed significant (KG) increase (p<0.05). RD decreased significantly in both groups. The results of Friedman test were significant for clinical indices (p<0.05), except for PD in conrol group (p=0.166). EMD showed the same results as CTG with relatively easy procedure to perform and low patient morbidity.

The aim of this study was to evaluate the durability of antibacterial effect of tetracycline in different conditions in microbial culture. In this experimental study, samples were the roots of extracted teeth of patients with periodontal disease, after removal of calculus and necrotic cementum on the teeth and exposure of dentinal tubules, the roots were shaped with a double-end diamond cutter disc and were kept in autoclave. Then samples were transferred into tetracycline solution with various concentrations and kept there for various periods of time. Each group was then washed in a 20 ml normal saline solution for 10 minutes, 1 week and 2 weeks and was transferred into a bacterial culture to evaluate the diameter of halo which demonstrates inhibitory effect of antibiotic on bacterial growth. The data obtained were analyzed using ANOVA test under spss software. The Maximum average of the diameter of the halo that was statistically significant (P value<0.05) in various situations of experiment was 17.5 mm. This which was seen in the teeth that were kept 60(s) in tetracycline solution of 100 mg/ml and also in the groups that were 240(s) in different concentrations of tetracycline and washed 10 minutes by normal saline. Adequate anti-bacterial effect was obtained in the group that was placed in tetracycline concentration of 50 mg/ml for 120 (s) and washed for 10 minutes by normal saline.

Color stability is an important property of denture base acrylic resin. Color changes indicate aging or damaged dental materials. The purpose of this study was to determine the influence of 3 different types of denture cleansers on the color stability of acrylic resin. This experimental study was performed on 40 samples fo 10×55 mm acrylic resins including 10 samples in the control group (BAYER) and 30 samples in the case group. Each group was then divided into 2 categories of smooth and coarse samples. Three cleanser solutions were then prepared as follows: 1. A 200 ml plate of 5.25% sodium hypochloride, 2. A 200 ml plate of varda + vinegar and 3. A 200 ml plate of water with a cleaner tablet named Corega. A spectrophotometer was used to record the initial and final color of each sample before and after placement in the cleaner solutions. Statistical data analysis was done using non parametric Kruskal- Wasliss AND Mann-Whitney Test. The difference between 5.25% sodium Hypochloride and other cleansers in terms of color changes was statistically significant (p<0.001). The Corega tablet solution demonstrated a greater effect on color changes of coarse surfaced acrylic resins compared to smooth surfaced resins. Use of 5.25% sodium hypoclorite cleaner will lead to a higher degree of color change in acrylic resins. In addition, the cleaners demonstrate a greater effect on coarse surfaces compared to smooth ones.

One of the problems encountered during a root canal preparations is preserving the minimum thickness of the canal walls. This study is aimed to evaluate the effect of final apical file size on residual dentin thickness of apical third of canal. In this experimental study, the initial images of the mesiobuccal canal of 40 extracted mandibular first molars were provided and measured at the levels of 1, 2.5, 4mm from the apex by CT cone beam. The specimens were divided in to 4 groups and canal preparations were done by RaCe rotary system. Master apical file size was selected based on #25, #30, #35 or #40(taper 0.04) in each group. Then, post preparation images were obtained at the previously mentioned positions. The initial and residual dentin thickness, also the amount of dentin removal were evaluated and analyzed statistically by ANOVA and TUKEY’S post hoc test. In intergroup and intragroup evaluation there were no significant differences in the amount of initial and residual dentin thicknesses also in dentin removal at any levels. There was a significant statistical difference in the amount of dentin removal at 1mm level for mesial surface (p=0,026). The least residual dentin thickness were found in mesial surface which at 1,2.5 and 4 mm levels from the apex were 0.43±0.17, 0.52±0.16, 0.57±0.16 mm respectively. Based on this study the file size #35 and #40(taper 0.04) with no significant canal transportation can be used as a master apical file in canals with 20-35 degree curvature.

Fluoride release in oral cavity is effective in prevention of caries in the walls of cavities and remineralization of initianal lesions. There is considerable variation in the amount of fluoride release from restorative materials. The aim of this study was to determine the amounts of fluoride release from three self-cured glassionomers, GC, SDI, SDS in distilled water and artificial saliva. Through an in Vitro study 6 specimens of each three glassionomers were prepared. One specimens of each materials was placed in distilled water and the other three disc inserted into non-fluoridated artificial saliva. Fluoride release was determined at 1,7, 14,28,56,70,84 days by using a fluoride ion-specific electrode. Data was analyzed using repeated measurement ANOVA and LSD test. Pattern of fluoride release from three glassionomers were similar. The highest amounts of fluoride was released from SDS into water and artificial saliva(p<0/001). GC and SDI released similar amount of fluoride in water. Apart from the type of glassionomers, fluoride release into the water was higher than artificial saliva. The highest amount of fluoride was released from SDS into both water and artificial saliva(p<0/001).

Adequate disinfection of surfaces has always been a controversial issue in the dental industry. Several claims have been made by the manufactures as to the efficacy of the different products introduced for disinfection of surfaces. The aim of this study was to assess the antibacterial efficacy of three surface disinfectants on dental operatory surfaces. This experimental study was conducted on 60 samples of dental units using three disinfectants: Alprocid, Microzed and deconex. Sampling was done before the disinfection from various parts of the dental units including head rest, light handle, air-water spray and the tray. Sampled surfaces were then disinfected with one of the disinfectants according to the manufacruer's guidelines. Post disinfection samples were obtained from the surfaces using a sterile swab. They were then cultured on blood agar and macconkey plates and incubated at 37 c for 24 hrs. The colonies were counted and isolates were identified using specific tests. Data was analyzed using Wilcoxon signed- rank test and kruskal-wallis test. Bacillus subtilis had the highest incidence and E.coli was reported to have the lowest incidence prior to disinfection. There was statistically significant difference in bacterial count (cfu/ml) before and after the disinfection (p<0.001), however, no significant difference was found within the three disinfectants in terms of antibacterial efficacy (p>0.05). Only decconex solution was found to remove all bacteria over the manufacture's recommended time. All imported disinfectant products should be re- evaluated to assess their antimicrobial efficacy on specific bacterial strains in Iran.

The aim of this study was to compare the number of mast cells in OLP and OLR to facilitate diagnosis of these lesions. This descriptive-analytic study was done on 34 paraffin blocks of Oral Lichen Planus(23 women and 11 men with mean age 47/35 ± 13/01) and 26 paraffin blocks of Oral Lichenoid Reaction (14 women and 12 men with mean age of 40/46 ± 12/91). Samples were from archives of pathology department of Babol dental school and Shahid Beheshti Hospital. 5 micron slices from blocks were prepared and stained with Toluidine Blue using standard methods. Then they were evaluated with light microscope. Total number of mast cells, number of degranulated mast cells and their ratio were assessed and the data was analysed with T test and Mann-U-Whitney test. The total number of mast cells and number of degranulated mast cells in OLP group were significantly higher than OLR group(p<0/05), but the ratio of degranulated mast cells to total number of mast cells had no significant difference (p>0/05). The results show a higher total number of mast cells and degranulated mast cells in OLP compared with OLR. These results may serve to be a diagnostic criteriia in differentiation of OLP from OLR and various treatment plans.

Backround: Basal cell nevus syndrome (BCNS) is an autosomal dominant inherited condition. The syndrome presents with multiple jaw cysts (more often,OKC), skeletal abnormalities, ectopic intracranial calcification, multiple basal cell carcinomas of the skin. The prevalence of Gorlin syndrome is estimated to be about 1/60000 to 1/120000. This syndrome if often distinguished in third decade of life.In this article a rare case of Basal cell nevus syndrome is reported. The case was a 23 year- old male patient with the chief complaint of exiting pus from the left side of his mandible (Buccal of first molar) who was referred to Islamic Azad University (Dental Branch) Radiology Dept. In radiographic assessment (panoramic radiography) multiple cystic lesions and thus impacted teeth in maxilla were seen. In histopathological view, epithelium of odontogenic cyst, keratin debries and Palisaded basal cells were seen in both jaws. The definitive diagnosis was multiple odontogenic keratocysts. Treatment was done first by marsupialization, enuclation and curettage. In three months follow up, recurrance wasnot seen.