[Shear bond strength of zirconia post to root dentin with two different cements and comparison with fiber posts]

In the recent years, the demand for esthetic restoration led to development of tooth colored post. The establishment of reliable retention between post and root canal is an important factor. Current prefabricated tooth-colored posts are fiber and zirconia posts. Loss of fitness in these posts reduces the post retention; therefore, there is a need for fabricating a tooth colored post that may be fitted in the root canal. The aim of this study was to compare the bond strength of fiber posts and custom made zirconia posts with two cement types [resin cement and zinc phosphate] to root dentin. Thirty-two single root extracted teeth were prepared and endodontically treated. They were divided into two groups [fiber post, zirconia post]; in each group two cement subgroups [zincphosphate and panavia F2] were used for cementation. Bond strength was measured with the push-out method. Failure modes were observed under a stereomicroscope [20x]. Data were analyzed with the two way ANOVA test. In both post groups, bond strengths of panavia F2 were higher than zinc phosphate. The least bond strength was for fiber post/zinc phosphate group [4.60MPa] and the highest bond strength was for zirconia/Panavia F2[14.92 MPa]. Most of the failures were at the post-cement interface. Higher bond strength may be achieved with custom made zirconia post and resin cement than fiber posts. So, fitness is a critical factor in post retention and we should not rely only on the bonding ability of resin cement for post retention

[Effects of different surface treatments on bond strengths of a non-metallic post in root's canal]

The establishment of reliable bonds at root-post-core interfaces is critical for the clinical success of post retained restorations. Severe stress concentration at post-cement interface increases the probability of post depending from the root. The aim of this study was to investigate the effects of different surface treatments on bond strengths of a non-metallic post in the root. Fifty extracted human canines or premolars that had just one root canal were endodontically treated. D.T Light Posts [RTD/France] received surface treatments in five categories: 1] Application of silane. 2] Sandblast with Alumina particles. 3] Sandblast with Alumina particles+ application of silane. 4] Etching with hydrofluoric acid+ application of silane. The posts were cemented in roots using panavia F 2.0 resin cement. A push-out test was performed on three different sections of each root to measure bond strengths. Data were analyzed with ANOVA and Post hoc tests at P<0.05. Failure modes were observed under a stereomicroscope [10]. Surface treatments used in this study [silane application, sandblast, sandblast+ silane, HF etching+ silane] did not increase the push-out bond strengths of fiber post used in this study. [P>0.05]. The most failures in different groups of surface treatments occurred at the cement material-post interface. The use of silane, sandblast method and etching with HF did not increase the push-out bond strength of fiber post used in this study

Leprosy elimination campaign in Qazvin province, Islamic Republic of Iran [2006-07]

Multi-drug therapy [MDT] and Leprosy Elimination Campaigns [LEC] are the major strategies for eliminating leprosy. We report the results of a LEC conducted in 2006 in Qazvin. A total of 1987 individuals [1379 household contacts of 319 registered leprosy patients and 608 people from 3 endemic villages with a high prevalence of leprosy] were examined for detection of new cases of leprosy. All new cases were given MDT and were reviewed after a year. There were 256 suspected cases of leprosy, 13 of whom were confirmed as new cases [7 were classified as multibacillary leprosy]. None had visible deformity nor was < 20 years old. All patients completed the recommended MDT course. The few cases detected suggest that in low prevalence areas, a long-term approach of integrated leprosy services and disability management may be more appropriate than LEC as a leprosy elimination strategy

[In vitro evaluation of Fuji IX glass ionomer to microleakage after exposure to hydrogen peroxide 35% in class V restoration]

Fuji IX packable glass ionomer has anti-carious properties by adhesion to tooth structure. It seems to provide adequate seal between tooth structure and restoration due to the development of ionic crosslinks. Furthermore, bleaching may affect the marginal seal of restorations, subsequently increasing the leakage of oral fluids and bacteria into the restored structure. The aim was to evaluate the effect of packable glass ionomer [Fuji IX] on the microleakage of Class V restoration exposed with and without H2O2 35%. Forty sound human molars and premolars were selected and class V standard cavities were prepared on each tooth. The specimens were assigned in two case and control groups while cases were exposed to H2O2 35% for the subsequent 5 days [30 minutes each day thrice] and the controls were stored in serum physiology. The specimens were thermocycled, stained with fushin and sectioned longitudinally. The microleakage scores were determined and subjected to Mann-Whitney U and Friedman tests in both groups. The mean and median of leakage scores in four regions of control specimens were 1.588 and 1.625 while the ratios were 1.913 and 2.25 for the teeth exposed to H2O2. The teeth exposed to H2O2 35% leaked higher than control specimens in the mesial region [p<0.04], while no significant differences were observed between two groups in the other areas. The use of Fuji IX glass ionomer cements in the restoration of class V cavities is an acceptable treatment modality for the restoration of bleached teeth

Postoperative thermal sensitivity reduction after amalgam fillings; A clinical evaluation and presentation of a new method

Prepared cavities are usually treated with liners prior to amalgam placement. Light cured glass ionomer [RMGI] have been widely used for this purpose. The aim of this study was to compare the effect of RMGI on decreasing postoperative sensitivity with a new method of applying self etch bonding and glass ionomer simultaneously. In a blind randomized clinical trial study, A total of 36 patients with 2 deep caries in their posterior teeth [cavities with less than 2 mm distance from pulp in radiography] were included. Diagnostic tests [cold-heat, percussion, electric pulp test] were performed for each tooth prior to final restoration. After cavity preparation, one tooth was treated by light cured glass ionomer, the next one with SE bond and glass ionomer randomly, followed by amalgam restoration. Diagnostic tests were performed three days, thirty days and three months after amalgam restoration. The statistical analysis was performed using SPSS software version 11.5 as well as Friedman and Wilcoxon signed-rank tests. In second follow up, the sensitivity to cold was significantly less than the conventional method [P < 0.05] in our suggested compound method. However, there was no significant difference between the two groups when using the other vitality tests. Using SE bond and light cured glass ionomer simultaneously was an effective new method of decreasing the postoperative sensitivity in short term, [1 month] although, there was no difference between the two groups in the long term

[ investigation on the effects of surface extension on dental pulp due to the application of dentin bonding agents [In vivo study]]

Background and aim: The application of dentin bonding agents in operative dentistry, has led to numerous advantages such as micro leakage reduction. The goal of this study was to clarify the possible effects of dentin bonding agents on dental pulps, in contact with dentinal extended surfaces

Materials and Methods: in this experimental study, 72 restorations were made on the anterior teeth of' six adult dogs: Restorations were divided into four groups. Group 1: Small C1V cavities restored directly with composite and denin bonding agent. Group 2: Large cavities [prepared for full coverage crown] restored indirectly composite and dentin bonding agent. Group 3: Large cavities [prepared for full coverage crown] restored with composite and cemented polycarboxylate cement indirectly. Group 4: Large cavities restored with composite crowns and cemented with resin cement along with dentin bonding agent. After 7,25 and 60 days animals were killed and histopathological studies were made on their pulp tissues. Data were subjected to one-way ANOVA, Kruska-Walis, Mann-Whitney and U-Wilcoxon tests

Results: there were significant differences between groups 1 and 2, groups 2 and 4, groups 1 and 4 and groups 3 and 4 [p<0.05]. Generally, the most irritation was observed in group 4 and groups 2, 3 and 1, respectively. In-group 1, a slight inflammation was found after 7 days that decreased or totally eliminated in 25 and 60 days. In-group 2, all inflammatory markers were more then group 1 and some of then remained after 60 days. The inflammatory markers, in-group 3, were more than group 1 and considerably less than group 2 and decreased in 25 and 60 days. In-group 4, all markers in all periods, were more than other groups, with its peak after 60 days

Conclusion: it seams that dentin bonding agents put irrelative effects on dental pulp. If other factors such as previous irritations, or those associated with cavity preparation methods or extensive surface contacts were present, more or even irreversible changes could be made in dental pulps