JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2012 | Volume:24 | Issue:2 (83)|Papers Count:12

Background and Aim: Microleakage is an important problem with direct restorations and familiarity with its contributing factors is of utmost importance. The aim of this study was scanning electron microscopic evaluation of marginal integrity in three types of class V tooth-colored restorations and the effect of load cycling on their microleakage.Materials and Methods: In this in vitro study, class V cavity preparations were made on the buccal and lingual surfaces of 30 bovine incisors (60 cavities). The specimens were divided into three groups (n=10 each or 20 cavities) and restored as follows: group 1: with Filtek Z350 (nanocomposite), group 2: Fuji IX/G Coat Plus (CGIC), and group 3: Fuji II LC (RMGI).All specimens were finished and polished immediately and were thermocycled (×2000, 5-50oC). In each group, half of the teeth were load cycled. Epoxy resin replicas of 12 specimens were evaluated under FE-SEM and interfacial gaps were measured. Finally the teeth were immersed in 0.5% basic fuchsine dye for 24 hours at room temperature, sectioned and observed under stereomicroscope. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests and a comparison between incisal and cervical microleakage was made with Wilcoxon test.Results: It was shown that the mechanical load cycling caused a statistically significant increase in cervical microleakage of Fuji IX and Fuji II LC and in incisal microleakage of Fuji II LC. Microleakage in Z350 with load-cycling and Fuji IX with and without load-cycling was significantly higher in cervical compared with incisal area. Both incisal and cervical microleakage were significantly different among these materials under load-cycling.) Fuji II LC<Fuji IX<Z350).Conclusion: It was concluded that the marginal sealing ability of Fuji IX under load-cycling was better than that of Fuji II LC. Z350 showed better marginal integrity while being load-cycled than both Fuji II LC and Fuji IX.Qazvin University of Medical Sciences. Qazvin, Iran.

Background and Aim: Adjustment of an accurate curve to the dental arch is an important part of orthodontic treatment. Our goal was comparing the fitting accuracy of two curves constructed by different numbers of clinical bracket points (CBP) to the dental arch form using 4th degree polynomial function.Materials and Methods: A mathematical formula associated with a polynomial function was used to reconstruct the dental arch forms of 18 adolescents (18 casts) with normal occlusion. CBPs were marked on every tooth present in each maxillary and mandibular model (second molar to second molar) using an orthodontic bracket positioning gauge. A coordinate measuring machine (CMM) was used to record the coordinates of each CBP (x, y). Then a curve fitting software was used to obtain the best 4th degree polynomial function and the associated curve fitted to all 14 CBPs. Another polynomial 4th degree function curve was obtained for the same models using CBPs only on central incisors, canines and second molars. Curves for each model were compared using statistical values including correlation coefficient, standard error, sum of residuals and RÙ2.Results: The mean root squares for curves fitted to 14 points in all samples were 0.8855 and it was 0.9629 when 6 points were compared with 14 points. The intraclass correlation coefficient (ICC) between curves fitted to 6 and 14 points was 0.946 in mandible, 0.983 in maxilla and 0.969 for both.Conclusion: Six CBPs were enough for proper fitting of 4th degree polynomial function to dental arch forms of both jaws.

Background and Aim: Reconstructive treatments in dentistry aimed at achieving complete regeneration of destroyed structures both in soft and hard tissues. To date, this goal has been tried to accomplish using various bone grafts, growth factors, and barrier membranes. Stem cells are the most fascinating area of biology today and have been used clinically in the field of medicine to treat many incurable diseases.Materials and Methods: The English literature indexed in in the MEDLINE/PubMed database was systematically searched and original papers were critically reviewed on this subject, until the second quarter of 2011. Additional papers were obtained by manual searching reference lists of previously published review papers.Results: More than fifty years ago, the first allogenic hematopoietic stem cell was transplanted in patients. However, the promise of other stem cell populations for tissue replacement and repair remains unachieved. When considering cell-based interventions for tissue regeneration, the factors influencing therapeutic success and safety are more complicated than for traditional treatments. So, it is important for dentists to have a brief understanding about the principles and clinical applications of stem cells in tissue engineering field.Conclusion: This article reviews the most recent published data to regenerate dental and periodontal tissues based on scientific principles and provides fundamental information to readers about the different aspects involved in tissue engineering. Ideal combination of cells, scaffolds, and growth factors for tissue engineering may be extended over future years. The findings collected in this literature review show that we are now at a stage in which engineering a complex tissue, such as the periodontium, is no longer an unachievable goal and the next decade will certainly be an exciting time for dental and periodontal research.

Background and Aim: Prefabricated posts are advantageous in restoring endodontically treated teeth because of their lower cost and operation time. Since selecting a suitable restoration is important in the survival of these teeth, in this study fracture resistance and the mode of failure of endodontically treated teeth restored with three different post and core systems were evaluated.Materials and Methods: In this in vitro study, 36 human premolars were divided into three groups; namely, group 1, non precious cast post and core; group 2, prefabricated metal post with amalgam core; group 3, FRC post and composite core. All groups received crowning. Specimens were thermocycled and loaded until definite failure. The fracture resistance and failure modes were analyzed with one way ANOVA and Fisher Exact tests.Results: The mean failure load for the three groups was 794, 647 and 724 N, respectively. Statistical analysis did not show any significant differences between the fracture resistance of the three experimental groups (P=0.0579). All failures in group 1, eight in group 2 and three in group 3, were unrestorable. Fisher’s Exact test showed significant difference between group 3 and the two other groups (P<0.05).Conclusion: If there is a 2-mm ferrule, the type of post and core does not have a significant effect on the fracture resistance, but it has a significant effect on the failure mode.

Background and Aim: Exercise is one of the activities to achieve fitness; therefore it should be performed in an appropriate way and its side effects should be minimized. It has been mentioned in the literature that in physiologic activities, there are important factors in the serum and saliva which have a significant role in dental and oral health, especially on dental caries. In this study, we decided to figure out how these oral health related factors are altered in endurance exercise.Materials and Methods: In this study, the samples included nineteen 18 to 25-year-old beginner male athletes. Two samples of saliva were taken, one before running for control and one after 1000 meters for test. Salivary pH was digitally measured immediately after collecting the samples. Cortisol and alpha amylase of the saliva in both control and test samples were evaluated by ELISA method. Data were analyzed with SPSS software and evaluated with descriptive statistical methods.Results: Endurance exercise in beginner athletes increased the mean alpha amylase level in their saliva from 59.57 to 107.52 IU/mL and the salivary cortisol from 2.73 to 3.60 Ng/mL. The mean salivary pH showed a 0.56 decrease (p<0.001).Conclusion: There was an increase in the salivary cortisol and alpha amylase level and a decrease in salivary pH after endurance exercise.

Background and Aim: Dental adhesives are widely used in modern dentistry to provide retention of composite resin restoration and to reduce associated marginal microleakage. We aimed to evaluate the effect of adding silica fillers to adhesive on microleakage of composite restorations in different times.Materials and Methods: Forty-eight premolars were collected in 0.5% chloramine T solution. The teeth were divided into two groups. CLV cavities were prepared. In the first group, SE bond and in the second group, experimental unfilled SE bond were applied. In subgroups 1 of both groups, the teeth were incubated for 3 months then evaluated. In subgroups 2 of both groups, evaluation was performed after 24 hours. Cavities were filled with Z250 composite resin. Before incubation, samples were thermocycled at 5 to 55oC in 1000 cycles, then immersed in silver nitrate solution and afterwards developer solution for microleakage evaluation. They were then mounted, sectioned and observed under steriomicroscope and scanning electron microscope for scoring. The data were analyzed with Kruskal-Wallis and Mann-Whitney tests.Results: There was significant difference in microleakage between groups in different times. There was no significant difference between occlusal microleakage regardless of time (p<0.001). The difference between cervical microleakage of two adhesive types was not significant (p=0.533). There was significant difference between 24 hours and 3 months storage (p<0.001). No significant difference was detected between filled and unfilled adhesives regardless of time (p<0.001).Conclusion: Although there was no significant difference between the two adhesives, unfilled adhesives performed slightly better than filled adhesives.

Background and Aim: Orofacial granulomatosis (OFG) comprises a group of diseases characterized by non-caseating granulomatous inflammation affecting the soft tissues of the oral and maxillofacial region.Wiesenfeld introduced the term orofacial granulomatosis in 1985 for the first time. The precise cause of OFG is unknown; however, some theories have been suggested including allergy, infection and genetic predisposition.The clinical presentation can be highly variable, making the diagnosis difficult to establish.The aim of this review was to define clinical features, differential diagnosis and treatment protocols of OFG.Materials and Methods: All English articles from 1950 to 2010 in Pubmed, InterScience, ScienceDirect, Google Scholar databases were searched using the keywords: orofacial granulomatosis, approach, and treatment. Persian articles were also selected from Iran Medex.Results and Conclusion: Because of the relatively nonspecific clinical findings associated with a variety of granulomatous diseases, the diagnosis of orofacial granulomatous often presents a dilemma for the clinician. The most common differential diagnosis includes Crohn’s disease, sarcoidosis, and infection. However, a variety of other conditions may be associated with granuloma formation. Often an extensive clinical, microscopic, and laboratory evaluation may be required to reach to definite diagnosis and proper treatment.

Background and Aim: Using different osteogenic growth factors, which is still under investigation, is a favorable method for bone regeneration. This systematic review is aimed at evaluating the effects of different growth factors and their carriers on osteogenesis.Materials and Methods: Electronic databases (Medline, EMBase and Cochrane) were searched by the authors for articles published from 1999 to April 2010. Clinical and animal studies evaluating bone formation by applying a specific growth factor and the related carrier were included in this investigation. Obtained data were organized in a table and evaluated through a qualitative analysis.Results: Sixty-three studies most of which evaluated the effects of BMP-2 osteogenesis in different models were included in this study. Totally, twenty-five carriers were applied with different growth factors in the experiments. Among these carriers, poly lactic-co glycolic acid (PLGA), hydroxy apatite/tricalcium phosphate/absorbable collagen sponge (HA/TCP/ACS) and BioOss were the most frequently used carriers with the growth factors in bone regeneration studies.Conclusion: The current evidence, although not strong enough, confirms that BMP-2 has more favorable results in osteogenesis compared with other factors. The carrier scaffold, methods of measurement (histologic or radiographic), type of animal, defect diameter and the length of follow-up are the variables that should be matched before reaching definite results for the effect of growth factors in bone regeneration.

Background and Aim: Temperature rise occurs during photoactivation of dental composites due to the exothermic polymerization reaction and different curing units. The aim of this study was evaluation of temperature rise in two kinds of composites with different curing units.Materials and Methods: In this experimental study, five samples of each composite resin (Filtek Z250, Filtek P90) were placed in two-millimeter deep Teflon molds which were 4mm in diameter. Curing was done from top surface with LED, high power LED and argon laser and temperature was recorded by a thermometer placed under the samples. After reaching room temperature, samples were cured and the temperature was recorded again. The time of maximum temperature was also recorded. The data were analyzed by two-way ANOVA and Tukey HSD.Results: Composites and curing units had statistically significant influence on the temperature rise (p<0.001) Silorane-based composites showed significantly higher temperature rise than methacrylate-based ones. A significantly lower rise in temperature occurred when illuminationwas performed by argon laser. There was no significant difference in temperature rise between the two types of LEDs. The type of composite had no effect on the time of maximum temperature and in all samples the maximum temperature was recorded at the beginning of irradiation.Conclusion: Silorane-based composites showed higher temperature rise than methacrylate-based ones. Argon laser revealed less heat than LEDs. The maximum temperature rise was recorded at the beginning of irradiation.

Background and Aim: The common method of caries status evaluation is the number of decayed, missed and filled teeth (DMFT) index. Recently the International Caries Diagnosis and Assessment System (ICDAS) has been introduced for a detailed evaluation of the dental caries. The aim of this study was to evaluate the caries status with this new system while comparing it with the DMF index as a common method.Materials and Methods: A total of 110 dental students were selected randomly and examined. Examination was done in the dental unit under good light circumstances. First, all surfaces of the teeth were cleaned with a brush, rubber cup and prophylaxis paste and then rinsed. Subsequently, examination was performed in each person by two calibrated examiners according to DMFT system and ICDAS (evaluation of teeth status in occlusal and smooth surfaces in dry and wet situations according to codes of this system) and the information forms were completed. Chi square statistical test was used for data analysis.Results: The mean DMFT was 7.16. According to ICDAS system nobody had 00 code meaning that at least one surface of 182 dental surfaces had a lesion. Only seven cases had codes 00-02. The results for codes 03 through 06 were as follow, respectively: 51, 49, 34, 2. Ninety nine cases had extracted or non-examinable teeth. The inter-examiner kappa coefficient was 0.916.Conclusion: The new system, ICDASl, provides more accurate information than DMF for the investigators and epidemiologists. The DMFT number does not show any details about the dental status of the cases.