Journal of Dental Medicine

The purpose of this survey was the determine of effectiveness of preventive precisures. 320 twelve years school student have chosen randomly. After determination of DMFT All of them divided to 4 groups. First group as control and the other groups were as oral hygiene education 6-fluoride therapy and sealant therapy group in a period of two years.Results of this study showed that fluoride therapy was more effective than the other procisures than oral hygiene instructions.

Background and Aim: The goal of endodontics is to seal the root canal system from the orifice to apical constriction completely and tridimensionally.Hence perforations during root canal therapy, because of caries or resorptions must be sealed and obturated with ideal materials. The aim of this study was to histologically compare two kinds of mineral trioxide aggregate Root MTA and Pro Root MTA for furcal perforation repair in developed teeth in dog.

Materials and Methods: In this experimental study, thirty teeth consisting of second, third and fourth mandibular premolars of five German shepherd dogs were selected. Twenty-four teeth were randomly divided into four experimental groups (6 teeth each). One pair of Root MTA and Pro Root MTA groups studied in one month and the other in three months intervals. Positive and negative control groups was each contained three teeth. In positive control group, perforations were not treated and negative control group contained intact teeth. In experimental groups perforations repaired after one week exposure to oral cavity with Root MTA or Pro Root MTA. After time intervals animals were subjected to vital perfusion and 6 m histologic sections were prepared. Inflammation and hard tissue formation were ranked by Cox criteria. Data were analysed using Mann-Whitney and Chi-Square statistical tests with P<0.05 as the limit of significance.

Results: There was statistically significant lower inflammation and higher hard tissue formation in three months Root MTA and Pro Root MTA groups compared to one month interval (P<0.05). There was no statistically significant difference in inflammation and hard tissue formation between Root MTA and Pro Root MTA in each intervals (P>0.05).

Conclusion: Mineral Trioxide Aggregate is an adequate material for furcal perforation repair in dog’s teeth. Root MTA could be a good substitute for Pro Root MTA considering the lower cost and similar characteristics.

Background and Aim: The final objective of root canal therapy is to create a hermetic seal along the length of the root canal system from the coronal opening to the apical termination and to accomplish the best adaptation of obturation material with canal walls. The purpose of this study was to compare the microleakage during lateral condensation of 0.04 and 0.02 tapered gutta-percha master cones.

Materials and Methods: In this experimental in vitro study, seventy two single canal teeth were selected and the crowns were removed. Canals were prepared using a step-back technique. Patency of the apical foramen was maintained and the teeth were divided into two experimental groups of 31 each Ten teeth were used as control group, out of which five served as negative and five as positive controls. The first and second groups were obturated with 0.02 and 0.04 tapered master cones respectively. All the teeth were obturated using lateral condensation technique. The teeth were placed in 100% humidity and 37^oc for three days. The roots were coated with two layers of nail varnish and one layer of stick wax except for the apical 2 mm. Teeth were placed in Pelikan ink for one week and sectioned vertically. The maximum depth of dye penetration for each tooth was recorded by two evaluators with stereomicroscope. The results were statistically analyzed using t-test with p<0.05 as the level of significance.

Results: The mean linear dye penetration for the first and second groups was 2.53 0.88mm and 4.89 1.20 mm respectively. The difference was statistically significant (P<0.001).

Conclusion: The results of this study showed that 0.02 tapered gutta-percha master cone, provided a significantly better apical seal than 0.04 tapered gutta-percha master cone.

Background and Aim: Root filling materials are usually in close contact with living tissues. So their biological properties like mutagenicity and cytotoxicity are important. These properties help us determine the potential damage to periapical tissues, or potential DNA mutations, and malignant transformation of the cells. The aim of this study was to evaluate the mutagenicity and cytotoxicity of four root canal sealers: AH Plus (Dentsply, DeTrey), Ketac-Endo Aplicap (3M ESPE), Sankin Apatite III (Sankin K.K), and Tubli-Seal EWT (Kerr).

Materials and Methods: In this experimental in vitro study fresh and set specimens from AH Plus, Ketac-Endo Aplicap, Sankin Apatite III, and Tubli-Seal EWT were immersed in culture medium for 1, 2 and 7 days. Cytotoxicity was assessed using tetrazolium bromide reduction assay (MTT) after 1, 2 and 7 days exposure of diluted extracts to L929 cells. Extracts of sealers in phosphate buffer saline (PBS) were used to examine the mutagenic effects by sos-umu test according to standard procedures. Data were analyzed using one way ANOVA, Kruskall Wallis, Mann Whitney and Post hoc tests with P<0.05 as the level of significance.

Results: Extracts of all freshly mixed sealers were cytotoxic. Ketac-Endo Aplicap and Sankin Apatite III showed the lowest toxicity respectively and Tubli-Seal EWT the highest. In contrast to other sealers, the cytotoxicity of Tubli-Seal showed no decrease with time. -galactosidase did not increase significantly thus none of the sealers showed mutagenic effects.

Conclusion: Based on the results of this study, Tubli-Seal EWT showed the highest cytotoxicity with time. Other sealers showed decreasing cytotoxicity with time. No mutagenicity effects was observed in none of  tested materials.

Background and Aim: Complete obturation of the prepared root canal is an essential step in endodontic treatment. Combination of gutta-percha and a sealer is widely used in clinical practice for root canal obturation, thus microleakage studies on sealing properties of these materials constitute an important part of endodontic researches. The aim of this study was to evaluate the microleakage of three root canal sealers: Apexit, AH26 and Dorifill by electrochemical method.

Materials and Methods: In this experimental study, 55 extracted human maxillary and mandibular cuspids were used. The coronal part of teeth were removed and the root canals were prepared using the step-back technique. The specimens were randomly divided into 3 groups of 17 samples each. Teeth in each group were filled with one of the sealers and gutta-percha by lateral condensation technique. 4 specimens served as positive and negative controls. An electrochemical method was used for evaluation of apical leakage with the electrical source potential of 10 V. Measurements of current flow through the test system were recorded every 72 hours. Data were analyzed by Kruskall Wallis and Mann Whitney tests. P<0.05 was considered as the level of significance.

Results: All specimens of the three groups showed low initial leakage that increased during the test period. The mean leakage in Apexit group was higher than AH26 and Dorifill groups. The lowest mean leakage was related to Dorifill group. Although no statistically significant difference was observed between this sealer and AH26.

Conclusion: The results of this study revealed that the best apical seal was obtained using Dorifill and AH26 sealers. The poorest result was observed in Apexit.

Background and Aim: Pit and fissure sealant therapy, is one of the most effective methods, in prevention of occlusal caries. Saliva contamination before curing the resin can increase the risk of failure in this method. The purpose of this study was to evaluate the effect of saliva contamination prior to curing on microleakage of pit and fissure sealants.

Materials and Methods: In this experimental in vitro study 21 sound human pre molars were selected and two standardized V-Shaped fissures were prepared on both buccal and lingual surfaces, then they were randomly divided into two equal groups. In the control group, the sealant was cured without any saliva contamination and in the case group, the sealed teeth were immersed in artificial saliva for ten seconds before curing. After thermocycling the samples were immersed in 2% fouchsin solution for 24 hours and then sectioned longitudinally in bucco - lingual direction. The specimens were then fixed and assessed under stereomicroscope to determine microleakage and dye penetration using paired student t. test. P<0.05 was considered as the level of significance.

Results: Analysis of data showed no significant differences in microleakage, between the two groups (p=0.178).

Conclusion: According to the results of this study saliva contamination of uncured sealant had no influence on microleakage.

Background and Aim: Since the clinical studies conducted to explore the effect of bonding agents on the success of fissure sealant are limited in number, the present study was conducted to compare the effects of two bonding agents on the success of fissure sealant of the saliva- contaminated teeth.

Materials and Methods: In this study, 63 teeth of 35 students aged 6-8 with healthy and newly-erupted upper jaw molar teeth, were selected and divided into two groups. In one group, single-bond and In the other, SE bond were used. As the teeth were newly erupted and the distopalatal area being in contact with the gingival sulcus and this fact that, this area was impossible to isolate, the distal sulcus of the contaminated teeth and the mesial area capable of adequate isolation were assumed isolated. For each group, after etching, the teeth on one side were treated with a sealant and the teeth on the other side were first bonded and then treated with the sealant. Hence, four groups were formed: bonded/isolated, bonded/contaminated, controlled/isolated and controlled/contaminated for any bonding agent. The results of the treatment were assessed in terms of the success and failure and then analyzed using Mc Nemar, and Chi-square tests and Cochran.

Results: The results of the study indicated that:1. Saliva contamination caused a significant increase in sealant failures(p<0.05).2. Use of the two bonding agents significantly increased the success of the sealant(p<0.05).3. Use of the two bonding agents significantly increased the success of the fissure sealant on the saliva-contaminated teeth, even more than when the teeth had been isolated and with only fissure sealant(p<0.05). 4. For the contaminated enamel, the results of SE bond were better than those of the single bond (p<0.05). However, in isolated condition the results of using single bond were better (p<0.05).

Conclusion: The results of the study supported the use of these two bonding agents in the treatment of fissure sealants under both isolated and contaminated conditions. Further, more SE bond seemed to be less sensitive to saliva contamination.

Background and Aims: Insolubility has been stated as one of the important characteristics of the materials which are used as sealers in the endodontic treatments. The aim of this study was to evaluate the solubility of four endodontic sealers (ZOE, Dorifill, AH26 and Tubliseal).

Materials and Methods: Five specimens from each sealer with similar size were prepared. After first weighing, the samples were stored individually in bottles containing 50 ml of distilled water at 37ºC. After 7 days, the specimens weighed and changes in the weight of each sample recorded with a digital scale. The data were analyzed by ANOVA and Post-hoc Tukey HSD tests.

Results: The results of this study indicated that Dorifill had the maximum solubility among all sealers with weight loss of 2.8%. Tubliseal and ZOE showed the weight loss of 1.4% and 2.3%, respectively. AH26 showed weight gain of 1.9% during 7 days. There were no significant differences in the mean weight changes between Dorifill, Tubliseal and ZOE groups (P>0.05). A significant difference was found between the mean weight changes of AH26 and that of the other groups (P=0.000).

Conclusion: From the results of this study, all tested sealers were in the standard limit of solubility, and thus, it could confirm this physical property of sealers for clinical applications.

Background and Aims: Moisture contamination of etched enamel during application of sealant is the most frequently cited reason for sealant failure. In previous studies, some hydrophilic bonding agents have been shown to bond to etched enamel after salivary contamination. The purpose of this study was to evaluate the enamelsealant interface following the use of primer on the saliva contaminated and/or moist etched enamel.

Materials and Methods: 40 extracted human incisors were selected. The enamel surfaces were etched for 20 seconds with an acid gel and rinsed for 30 seconds and dried until chalky surface was observed. Teeth were randomly divided into four treatment groups (n=10). Sealant (Deguseal mineral, Degussa) was applied on (1) etched enamel surface as a standard control group, (2) in conjunction with using primer material on moist etched enamel, (3) in conjunction with using primer material on salivary contaminated etched enamel, and (4) on wet contaminated etched enamel surface as a negative control group. Then, the specimens were observed with scanning electron microscopy (SEM) at ×1400 magnification. To evaluate the enamel resin interface, the number of resin tags was counted. Data were analyzed using one-way ANOVA.

Results: The results showed that primer used on moist enamel under sealant had no significantly difference in number and shape of tags in comparison with standard group (P>0.05). Application of primer on saliva contaminated enamel surface under sealant significantly reduced the number of tags and changed the shape and pattern of tags (P<0.001). Following application of sealant on contaminated and etched enamel alone, no resin tags formed.

Conclusion: Application of primer relatively reduced sensitivity to saliva contamination but the pattern was changed and number of tags reduced. Therefore, primer application might be useful whenever the isolation is not possible. However, it should be emphasized that restrict isolation in sealant therapy is recommended.

Background and Aims: Fissure sealant therapy is a national program in elementary schools in Iran. Therefore, evaluation of the parents' knowledge and attitude is necessary to improve the program.
Materials and Methods: In this cross-sectional and descriptive-analytic study, Iranian students were chosen in a randomized cluster manner. The questionnaires were filled-out by students' parents to evaluate their general information, knowledge, and attitude. Moreover, students were examined for having any fissure-sealed teeth. Data were collected and analyzed by multiple logistic regression tests.
Results: 414 boy students and their parents were participated in this study. 57.6% of parents knew that fissure sealant prevents the caries and 44.5% believed that fissure sealant is important to prevent caries. However, only 8.9% of children had fissure sealant. Parents' knowledge was significantly related to the source of oral health information and oral health education. Regular dental visits and high level education was effective in increasing the knowledge about sealant therapy. There was a significant relation between parents' attitude toward fissure sealant and level of education, oral health education and numbers and times of dental visit (P<0.001). There were a significant relation between tooth sealing and parents' oral health information.
Conclusion: Regular dental visits and oral health education have positive role in parent's knowledge and attitude and practice. So parents must be encouraged to have regular dental visit and dentists must be emphasized to give them necessary education. School is the best place for giving proper information to parents.

Background and Aims: Teaching of clinical skills is one of the most important aspects in training medical students. The aim of this study was to compare the effectiveness of videotaped and live demonstrations for applying fissure sealant on permanent molar teeth at Zahedan University of Medical Sciences (2010-2011).

Materials and Methods: Thirty 8th-semester dental students were randomly assigned in two groups (n = 15). In group 1, fissure sealant placement was taught using live demonstration while, in group 2, education was performed by videotaped demonstration. Then, each student applied fissure sealant on the patient's permanent molar tooth. The procedure of fissure sealant placement was assessed and scored by a pedodontist. The students were subsequently asked to rate how helpful the videotape or live demonstration had been. The data were analyzed using T-test and Chi-square test.

Results: The mean students' scores for videotaped and live demonstration were 16.5 and 16.53, respectively. There was no significant difference between the teaching methods according to students' scores (P>0.05). 33% of students rated videotaped demonstration as "good" for its helpfulness and 66% as "very good". However, live demonstration was rated as "good" and "very good" by 66% and 33% of students, respectively. There was no significant difference between two groups (P>0.05).

Conclusion: Both teaching methods were equally effective. Therefore, videotaped demonstration can be used in combination with live demonstration or as an alternative for it.

Background and Aims: A large number of investigations have revealed that physical and chemical alterations and weight loss could occur in composite materials exposed to acidic phosphate fluoride (APF) gel. The purpose of this study was to assess the microleakage of a fissure sealant and a flow composite exposed to acidulated phosphate fluoride (APF) gel.

Materials and Methods: In this in vitro study, 60 intact human extracted premolar teeth were used. After preparing the occlusal groove, the teeth were divided into two groups (n=30). Teeth were filled with either Helioseal fissure sealant (Vivadent, Germany) or Tetric flow composite (Vivadent, Germany). After that, each group was divided into two subgroups (n=15): 1.23% APF gel (Sultan, U.S.A) was applied in the case subgroups, while control subgroups were preserved in normal saline solution. All of teeth were covered with 2 layers of nail varnish except for the filling zone and 1mm around the border of filling. After submerging in 0.5% fushin solution, specimens were sectioned bucco-lingually. Then dye penetration through the filling and fissure sealant was assessed by means of a stereo-microscope. The depth of dye penetration was scored. The data were analyzed using One-way ANOVA and Levene test.

Results: The mean values of dye penetration were 1.26±1.09, 1.4±1.05, 1.2±1.37, and 1.4±1.35 for fissure sealant+gel, composite+gel, composite+normal saline, and normal saline groups, respectively. No significant difference was found in inter-groups (P=0.96).

Conclusion: Considering the result of the present research, APF gel had no significant effect on the microleakage of Tetric flow composite filling and Helioseal fissure sealant and thus, it can be applied for routine usage.

Background and Aims: When composite resin polymerizes, shrinkage stresses tend to produce gaps at the tooth/ restoration interfaces. Surface sealants may reduce or avoid problems related to the marginal interface. The aim of this study was to evaluate the effect of two different surface sealants (Fortify and Optiguard) on the microleakage of class V resin composite restorations.

Materials and Methods: Twenty three sound noncarious molars were collected. Totally, 45 Class V cavities with the occlusal margins in enamel and cervical margins in cementum were prepared in both buccal and lingual surfaces. The specimens were randomly assigned in three groups (15 cavities in each group) and then restored with a resin composite. After the finishing and polishing procedures, the restorations in each group were covered with a specific surface sealant, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled and then immersed in a 50% silver nitrate solution (tracer agent) for four hours, sectioned longitudinally and analyzed for leakage using a stereomicroscope in a blind manner. The marginal microleakage was evaluated at the occlusal and cervical interfaces and compared among the three groups using the Kruskall-Wallis and the Mann-Whitney U tests.

Results: Microleakage was found in all groups at both occlusal and cervical margins. Significantly greater leakage was observed at the cervical margins compared to the enamel margins of the material groups (P=0.005). There was no statistically significant difference among the groups at occlusal margins (P=0.66). In the cervical region, Fortify showed improved results and statistically presented the lowest degree of microleakage (P=0.003).

Conclusion: The used sealant materials presented different rates of effectiveness and Fortify decreased marginal microleakage significantly.

  Background and Aims: Since recurrent caries are one of the major causes of failure in resin restorations, the production of antibacterial resin composites was always under investigation. The aim of this study was to evaluate the efficacy of fissure sealants containing nanosilver particles against the Streptococcus mutans.

  Materials and Methods: In this experimental study, the antibacterial properties of two sealants (with fluoride (Clinpro 3M) and without fluoride (Concise 3M) was investigated with 0, 0.01, 0.02, 0.03, 0.04, 0.05% w/w after adding nano-silver using direct contact test. Sealants formed on the walls of 500ml micro tube and after curing, they left in contact with bacterial suspension. In periods of 3, 24, 48h, a 10 µl volume of liquid medium was placed in blood agar culture and after 24 h incubation at 37ºC, the number of S.mutans colony was counted by colony counter. Data were analyzed using ANOVA and
T-test.

  Results: Results reported sealants with fluoride comparing to non fluoride ones had significant effect on inhibition of S.mutans growth (P<0.001). The direct contact test demonstrated that by increasing the amount of nano particles, the bacterial growth was significantly diminished (P<0.001).

  Conclusion: While sealants with fluoride demonstrated antibacterial effect, sealants with incorporation of higher weight percentage of nanosilver particles, had stronger and more significant antibacterial effect in direct contact test.

  Background and Aims: Posterior palatal seal is one of the most important areas to support maxillary complete denture. The aims of this study was to evaluate the dimensional accuracy of both direct and indirect relining methods on the maxillary posterior palatal seal area.

  Materials and Methods: A maxillary edentulous model was selected. A 1.5 mm layer of wax was placed on the model to create a space for relining material and impression was done by the silicone material and 20 casts was prepared. By putting the wax on the casts and performed of flasking, 20 dentures were prepared. Direct reline method (as Chair side with GC reline) and indirect method (with Acrosoft-TC and firing with Acropars 100) were evaluated. The relined bases were put on the model and the spaces between them in five points (two points on the ridge , two points in the deepest part of palate and one point in the middle of palate) were calculated by the Stereo microscope and each calculations was repeated 5 times and the mean dimensional changes was measured. To compare the groups, data were analyzed using multivariate analysis.

  Results: The gap of P.P.S area was between 740.86 and 2356.49 . Direct method (1011.81±60.56) had a lesser gap in comparison with indirect (2056.8±13.13), and both method showed a significant statistic variance (P<0.0001).

  Conclusion: Direct method showed a lesser gap in comparison with indirect method. By direct method adaptation of the denture in the P.P.S area would be better.