JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2007 | Volume:19 | Issue:2 (63)|Papers Count:18

Background and Aim: Although rotary instruments have been used for cleaning and shaping procedures during root canal preparation; nevertheless, the most effective technique regarding the use of these instruments has not been determined yet. Therefore, this study was carried out to evaluate the distortion and fracture of Flexmaster and Profile files during root canal preparation. This process was carried out by Endo IT Control instruments on human molar teeth.Materials and Methods: A total of 60 human molar teeth with 10°-30° curved roots were randomly divided in two groups. Flexmaster and Profile files were used in the first and second groups using crown-down technique. The instrumentation speed, time and torque were controlled using Endo IT Control according to manufacturer's instructions. The fracture and distortion of files were evaluated in both groups.Results: There was not any instrument fracture in the study, but 3 distortion cases were observed (2 in Profile group and 1 in Flexmaster one). The difference between distortions in two groups was not statistically significant. Likewise, no relationship was found between distortion and repeated use of instruments in the sample. Conclusion: There was not any difference regarding fracture between the two groups. However, distortion of files in Profile group was more than Flexmaster group when Endo IT Control instrument was used.

Background and Aim: Composite resin restorations are widely used in dentistry, Therefore, it is important to identify possible causes of failures in this regard, The purpose of this study was to investigate the microleakage of two microfiled and hybrid resin composites following the use of 10% carbamide peroxide.Materials and Methods: In this experimental study, Class V cavities were prepared on the buccal surfaces of 150 human anterior teeth, These teeth were randomly divided into six groups and filled with two microfilled (D-E) and hybrid resin composites (B-C), The groups B and D were kept in contact with 10% carbamide peroxide for three weeks, Likewise, groups C and E were kept in contact with the same solution for four weeks, The specimens were rinsed and sectioned after being emmersed in 0.5% buffered fushin, and the microleakage was evaluated under stereomicroscope, Kruskal-Wallis and Mann-Whitney tests as well as Hotteling trace were used to determine the significant differences between the groups.Results: In comparison with the control group, composite microleakage was observed in all groups after emerging the samples in 10% carbamide peroxide, Microleakage was lower in the three-week group, when compared with the four-week one, However, the difference was statistically significant in the microfilled group, Conclusion: The microfilled composite restorations should be changed after using carbamide peroxide.

Background and Aim: The purpose of this study was to evaluate the epical sealing quality by using a dentin bonding agent as a root canal sealer with the single cone gutta-percha obturation technique.Materials and Methods: 36 single rooted human mandibular premolars with straight canals were collected. Ten canals in group 1 were prepared with standard technique and were obturated with Tubliseal EWT and a single cone of gutta-percha. Ten canals in group 2 were prepared and obturated with the same techniques. Ten canals in group 3 were prepared with step back technique and were obturated with Tubliseal EWT and lateral condensation technique. The remaining six teeth were selected as negative and positive controls. All the specimens were allowed to set for 48 hours in 100% humidity at 37°C. Dye penetration technique was used to evaluate the apical seal quality. The groups were compared for differences in the amount of dye leakage.Results: The mean and standard deviation of dye penetration were 5.01±2.101, 3.04±0.789, 2.49±1.379 mm in groups 1, 2 and 3 respectively. It was shown that average dye penetration in group 1 was significantly more than groups 2 and 3.Conclusion: The lateral condensation technique as well as single cone technique with a dentin bonding agent as a sealer yielded almost similar sealing abilities without any significant differences in the amount of dye leakage.

Background and Aim: The inflammatory changes in gingiva as well as periodontal diseases are the most common oral conditions found in diabetic patients. The objective of the present investigation was to compare the oral health and periodontal disease status in diabetic and non diabetic children and adolescents.Materials and Methods: Cases were composed of 68 registered diabetic individuals aged 5-18 years old. The control group was composed of 68 non-diabetic sex and age-matched persons, who were among the out-patient visitors of Mashhad School of Dentistry. A questionnaire was used to collect information from medical records and clinical examinations. The statistical analysis was conducted in order to assess OHI-S, PI and GI indices in each patient. Results: The mean OHI-S was 1.56±0.59 and 1.63±0.51 in diabetic and non-diabetic children respectively. The mean PI was 1.42±0.85 in diabetic and 0.71±0.54 in non-diabetic children. The mean GI was 1.20±0.45 and 0.77±0.50 in diabetic and non-diabetic children respectively. Conclusion: Although there was no significant difference between the two groups regarding their oral hygiene status, diabetic children had higher frequencies of periodontal diseases and gingivitis compared to sex and age-matched non-diabetic controls. Therefore, it is necessary to design and promote periodontal disease prevention programs for young diabetic patients.

Background and Aim: "Micro 10" and "Deconex 53 plus" are current samples of new QAC generation. Although these compounds have been widely evaluated, there are still some doubts about their disinfecting power. The purpose of this investigation was to evaluate the clinical efficiency of Micro 10 and Deconex 53 plus. Materials and Methods: In this single blinded study, the microorganisms' suspension was prepared according to AOAC guidelines (containing standard and resistant pseudomonas aeruginosa, staphylococcus aureous, salmonella typhi muriom, bacillus subtillis, mycobacterium bovis, trichophyton menta grophit). The instruments (syringes) were contaminated using a sampler and the above mentioned suspension. After cleaning and disinfecting the instruments according to manufacture's instructions, samples were collected for cultivation and incubation. The colony formation units were observed and data was analyzed using fisher's exact, chi square and Mann Whitney tests in order to identify the group differences and significance levels.Results: Micro 10 5% and Deconex 53 plus 2% had similar bactericidal effect on pseudomonas aerugmosa, staphylococcus aureous, salmonella typhimuriom and fungicidal effect on trichopyton menta grophit with no significant difference compared to autoclave. However, in comparison with Deconex 53 plus 2% and autoclave, the Micro 105% showed significant effect against bacillus subtilis and mycobacterium bovis (P<0.001). Conclusion: Deconex 53 plus can be classified as an intermediate level disinfectant.

Background and Aim: The aim of this study was to compare the efficacy of air-polishing devices (APDs) with hand instruments and ultrasonic scalers when used for interdental subgingival plaque removal. Likewise, the effectiveness of APD with and without abrasive powder was evaluated.Materials and Methods: A total of sixty single-rooted teeth were treated in fifteen periodontal patients with 4-6mm mesial probing depth (PD). The selected procedures were hand instruments (Gracey curettes), ultra sonic scalar, APD without powder and APD with powder. Before and immediately after the treatment procedures, subgingival plaque samples were collected from the mesial aspects of these teeth. The anaerobe cultivation method was utilized to assess the mean reduction of total colony forming units (CFU) immediately after treatment.Results: Subgingival microorganisms were significantly reduced in all methods. The mean CFU differences between before and after treatments were significant (P<0.001) for all procedures. However, no significant difference was observed in the effectiveness of various methods. On average, all methods were able to reduce subgingival microorganisms by 92%. There was also a positive correlation between the colony counts before and after treatments (r= 0.52).Conclusion: Using APD is as effective as hand instruments and ultrasonic scalers for interdental subgingival plaque removal in cases with up to 6mm probing depth. The use of abrasive powder does not enhance the effectiveness of APD in subgingival plaque removal.

Background and Aim: This study was conducted to evaluate the compressive strength of 3 brands of Zinc Phosphate Cements determining the influences of eye estimated (rough measurement) of powder/liquid ratios on the compressive strengths of these cements.Materials and Methods: The three tested Zinc phosphate cements were Hoffmann's [Harvard Dental GmbH], DeTrey Zinc [Densply] and Ariadent [Asia Cherri Teb]. The specimens were divided into 6 groups, each one containing 10 samples. These samples were prepared according to ISO 9917 (2003) and stored in distilled water at the temperature of 37°C for 24 hours. The compressive strengths of samples were measured with the Zwick testing machine. The ANOVA and Tukey statistical tests were used to identify the significant differences between these groups.Results: There were significant differences between compressive strengths of cements prepared with manufacturer suggested mixing ratios and clinically used (eye estimated) ratios. The least compressive strength was recorded for Ariadent samples with clinical mixing ratio and the highest was recorded for Hoffmann's samples with manufacturer's suggested ratio.Conclusion: In clinically used ratios, Hoffmann's cement had the highest compressive strength. The differences between the strengths of manufacturer suggested mixing ratios and clinically used ones were the most in DeTrey Zinc cement.

Background and Aim: The aim of this study was to evaluate the shear bond strength (SBS) of composite/amalgam restorations when adhesive resin cement was used.Materials and Methods: 60 Acrylic cylinders were prepared using special Teflon molds. A square-shaped cavity was made at the center of each cylinder. The samples were divided into four groups (n=15). After amalgam condensation and burnishing in the first group, a two parts Teflon die with a cylindrical hole at the center was placed on the amalgam surface. These holes were filled with composite-resin. Single bond and Rely X-ARC were applied on amalgam surfaces respectively, prior to curing the composite-resins in the second group. In groups 3 and 4, the prepared amalgam samples were kept in 30C for 24 hours. Then they were identically roughened using burs. In group 3, composite was bonded immediately and in group 4, first single bond, and then Rely-X ARC were applied before curing the composite. The SBS was determined by DARTEC testing machine.Results: The mean SBS for the study groups were 9±2.77, 8.74±6.42, 6.13±2.35 and 8.25±1.43 respectively. The maximum value was related to group I and the minimum value belonged to group 3. However, there were no significant differences between the study groups.Conclusion: Application of Rely X-ARC in amalgam/composite interface did not cause any significant difference.

Background and Aim: The aim of this study was to evaluate the quality and effectiveness of Nisastan screw type implants over a two year follow-up period.Materials and Methods: 21 patients including 10 male and 11 female with the age range of 21-62 years old with anadontia in the posterior regions of their mandibles were selected to participate in this study. Total of 58 Nisastan implants were used in the lower jaws. After elapse of the osteointegration period, 64 units of fixed partial prosthesis were placed on these implants. Patients were evaluated clinically and radiographically at the loading time, one year and two years later. The survival rate and success indices like pocket depth, plaque index, bleeding index and crestal bone resorption were recorded.Results: The success rates of implants were 94.4% and stability of the abutments and prosthesis were 96.1% after two years. The mean crestal bone loss was 1.08-1.43 mm. The plaque index in 56.5% of areas was zero at the loading time while 64.5% of areas were zero at the end of study. The bleeding index in the 49.5% and 65.65% of areas was zero at those times respectively.Conclusion: The Nisastan Implants showed acceptable performance during the two year period of study.

Background and Aim: The purpose of this study was to compare the shear bond strength of three bonding agents known as Excite, Prime & bond NT and Clearjil SE Bond.Materials and Methods: Sixty premolar teeth were randomly divided into two groups. The buccal surfaces of 30 teeth in group 1 were cut by trimmer to expose the dentin in the coronal portion and those of the teeth in group 2 were cut to expose the dentin in the root portion. Mounted samples in acryl resin were randomly divided into three groups. The Excite bonding agent was used in groups (1-1) and (2-1); Prime & bond NT in groups (1-2) and (2-2) and finally the Clearfil SE Bond in groups (1-3) and (2-3). Then, composite Z100 was used to restore all cavities.Results: In coronal sections and in comparison between groups (1-1) & (1-2) there was no significant statistical difference. In radicular sections there was significant difference between (2-1) & (2-2) groups, (2-1) & (2-3) groups and (2-3) & (2-2) groups.Conclusion: Attachment to dentin either in coronal or in radicular sections had more bond strength when we use self etch bonding agent compared to total etch bonding agent. Also the type of bonding agent affects the bond strength in the root, but has little effect in the crown. Bonding agent with ethanol solvent has a greater effect than bonding agent with acetone agent.

Background and Aim: Enamel contaminations with salivary proteins or blood are the major reasons for debonding of brackets. The purpose of this study was to evaluate shear bond strengths of bonded brackets with enamel surfaces under different conditions.Materials and Methods: The Concise composite (3M, Unitek) was used for adhesion of 0.018 inch standard brackets (3M, Unitek). Fresh human saliva was used for contamination of enamel surfaces. 90 teeth were divided into 6 groups: 1- No surface contamination, 2- Contaminated after etching, 3- Contamination after application of bonding resin, 4- Contamination after etching, then re-etching, 5- Contamination after resin bond application, then re-etching and 6- Contamination after resin bond, then application of resin bond again. Surface contaminations were dried in all groups. After bracket bonding, the samples were held in distilled water in 37°C for 24 hours. Specimens were then thermo-cycled for 650 times at 5°-55° Centigrade. Shear bond strengths were measured by DARTEC machine. Data were evaluated by Duncan and variance analysis.Results: Statistical analysis of data reveals significant differences only in groups one and four (P<0.05). The maximum shear bond strength was observed in the fifth group (21.61±2.6MP) and the minimum in the third one. Conclusion: After salivary contamination of enamel, adequate clinical shear bond strength can be gained with drying of contaminated area and re-etching for 10 seconds. No washing is required in this case.

Background and Aim: The polishing and finishing procedures may cause topographical changes and introduce subsurface micro-cracks in dental composite restorations. The effect of Occlusal Index on the amount of wear in the posterior composite restorations was evaluated. Likewise, a comparison was made between the wear rates of Tetric Ceram and Ideal Makoo composite resin products.Materials and Methods: A total of 40 premolars were collected and randomly divided into four groups. Occlusal Indices were prepared with a transparent acrylic resin (Duralay). Class I cavities were prepared in all specimens. In two groups, teeth were restored with Occlusal Index. However, the restorations were completed without any Occlusal Index in the other two groups. Wear on the surfaces of these restorations were made by an oral cavity simulator and a tooth-brush machine. The vertical sections of the "pre-wear "and "post-wear "replicas were compared with a Projector Profilometer and the differences between the two sections were analyzed using two way ANOVA test at a=0.5.Results: The results showed that the mean-wear in index groups was higher. The findings did not show any significant difference between the wear rates of the two materials used in this experimental evaluation. Conclusion: The uses of occlusal index dose not decrease the wear of posterior composite restorations.

Background and Aim: A dowel in an endodontically treated tooth could transfer occlusal forces intraradicularly which may increase the vertical root fracture susceptibility. Ferrule is one of the methods by which tooth structure can be reinforced.Materials and Methods: Thirty freshly extracted central incisors were endodontically treated. The teeth were randomly divided into two groups. Those in the control group were treated using prefabricated post and composite core (with no ferrule), and the teeth in test group were treated with similar prefabricated posts and cores while having two mm ferrule height. All teeth were restored with full metal crowns. The specimens were mounted on a universal testing machine and a compressive load was applied to the long axis of the teeth until fracture occurred. Results: There was a significant difference between the ferrule and non-ferrule groups (P<0.000). The mean for ferrule group was 584N, while this value was 194N in non-ferrule group.Conclusion: The ferrule effect increases the fracture resistance of endodontically treated teeth that are restored with bonded post and cores.

Background and Aim: The study aim was to evaluate antifungal effects of Artemisia absinthium, Eucalyptus spp, Allium cepa, Cinnamomum zelanicum, Curcuma longa, Salvia officinalis, Mentha Piperita, and Calendula officinalis mouthwashes.Materials and Methods: Standard species of Candida albicans by the PTCC number 5027 was prepared from Pathogenic and Industrial bacteria and fungi collection center of Iran. Ten wild species were also prepared from the palatal mucus or buccal mucus of patients submitted to one of the clinics in Kerman. Extracts from the plants were made using percolation method with hydro alcoholic solvent followed by evaporation of the organic solvent under vacuum and then drying in a 50°C oven. Then 0.5 McFarland suspensions from all fungi species were prepared.These suspensions were used by both small well and tube methods. Results: All the extracts had antifungal activity against Candida albicans. However, this property in the first four plant-extracts was more powerful than the others.Conclusion: According to the results of this study, the extracts of Curcuma longa, Eucalyptus spp, Artemisia absinthium, Cinnamomum zelanicum had considerable antifungal effects.

Background and Aim: Among different treatment options for patients with Class III malocclusion, orthopedic protraction of maxilla can be a beneficial treatment procedure during the mixed dentition period. The aim of this study was to evaluate the cephalometric changes of Class III patients in the mixed dentition period following face mask therapy without any maxillary expansion.Materials and Methods: This study was conducted to compare the pre and post treatment conditions of 10 children in mixed dentition period that had class III malocclusion and maxillary deficiency according to the Steiner and Mc Namara's analyses. These patients were treated with protraction face mask without any maxillary expansion. The cephalometric changes of maxilla, mandible, soft tissue and dental relationships during treatment were recorded and analyzed using Paired sample T test.Results: Significant changes were found in several variables (P<0.05).The mean improvement in overjet was 2.3 mm, the N.Sn.Pog angle decreased 3.5 degrees and the soft tissue profile was improved greatly. A Class I molar relationship was also achieved. The IS.A and 1 to NA distances increased 2.8 and 2.3 mm respectively, resulting from anterior movement of maxillary incisors.Conclusion: Face mask therapy without maxillary expansion is able to improve the horizontal position of maxilla in Class III malocclusion during the mixed dentition period.