Journal of Dental Medicine

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Statement of Problem: Candidal colonies make up a part of natural oral flora and are considered as predisposing factors for opportunistic infections. Since hemodialysis leads to body Immune suppression and make patients susceptible to opportunistic infections, it is useful to investigate the relationship between hemodialysis and such infections.
Purpose: The aim of the present research was to study the relationship between oral candidal colony count and duration of hemodialysis and also to investigate the probable necessity for prophylaxis against oral candidiasis. Factors such as oral temperature, age, sex, denture, smoking, drugs, candidal microscopic view and clinical signs of oral infections, were also studied in relation to candidal colonies.
Material and Methods: The smear of posterior part of tongue and oral fluids from 114 hemodialysis patients in Khorshid hospital, Isfahan University of medical Sciences were cultured. The number of oral candidal colonies and their microscopic view were studied in relation to the duration of hemodialysis and other factors. To analyze the data, Pearson and Spearman statistical tests were used.
Results: No statistical significant relationship was observed between oral candidal colony count and the duration of hemodialysis.
Conclusion: Due to the abundant predisposing factors for oral candidal infection, the probability of oral candidiasis cannot be predicted based on a single factor, namely duration of hemodialysis. As a result,according to this study, the prophylactic prescription of antifungal drugs are not suggested in hemodialysis patients. However, the results of the present study should not be over generalized and more studies are required.

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Background and Aims: In this in-vitro study, the effect of multiple adhesive coating on the microshear bond strength of composite to dentin and surface microhardness of dentin after treatment with four adhesives (One Step Plus, One Step, Single Bond, Single Bond 2) were evaluated.

Materials and Methods: One hundred intact human molars were cut to obtain disks of dentin having 2 mm thickness. For the microshear bond test, sixty disks were randomly divided into four groups. In each group one type of adhesive was used. In one half of a disk two layers and in another half six layers of adhesive were applied. Cylinders with 1mm height was filled with a composite and light cured. The cross-head speed was 0.5 mm/min. Vickers microhardness was tested on forty dentin disks which divided into four groups and prepared in the same manner used for microshear bond test. Data were analyzed by Two-way ANOVA and Tukey tests.

Results: The highest and lowest bond strength were recorded as 29.49 ± 5.74 MPa (One Step Plus 6 layers), and 21.23 ± 4.83 MPa (One Step Plus 2 layers), respectively. The results indicated that One Step Plus bond strength in 6 Layers was significantly higher than 2 layers. The highest and lowest dentin hardness values were
39.08 ± 8.34VHN (Single Bond 2 layers) and 28.53 ± 5.98 VHN (One Step Plus 6 layers). None of the adhesives exhibited significant difference in hardness with regards to the layers applied (P>0.05). Presence of filler in adhesives had no significant effect on bond strength (P=0.05) whereas caused significant decrease in the dentin microhardness (P<0.05). In addition, type of solvent had significant effect on the bond strength and bond strength was significantly higher in acetone-base adhesives (P<0.05). However, dentin microhardness was significantly higher in the ethanol-base adhesives (P<0.05).

Conclusion: Multiple adhesive coating had no influence on the microshear bond strength of composite to dentin and dentin surface microhardness. It was dependent on the type of adhesive used.

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Background and Aims: Root canal obturation is of great importance in root canal treatment. Its purpose is to eliminate microleakage, re-entry and growth of micro-organisms in the root canal system. The aim of this study was to compare coronal salivary microleakage in obturated root canals using lateral compaction, single cone gutta-percha and System B vertical compaction methods.

Materials and Methods: In this in-vitro study, 80 single rooted, human extracted teeth were randomly divided into 3 experimental groups (n=20) and 2 positive and negative control groups (n=10). The specimens in each experimental group were obturated by using cold lateral compaction, single cone obturation, or continuous wave of condensation (system B). After that, coronal saliva leakage was evaluated. Data were analyzed using Survival analysis and Log-rank test.

Results: The results showed that all the specimens in the positive control group showed evidences of leakage during the first 7 days of study. None of the specimens in negative control group showed leakage during the 30-days period of the experiment. Survival test and log-rank test showed that at the end of the 30 days, there was significantly less resistance to coronal salivary leakage in single cone method compared with lateral compaction (P=0.039) and continuous wave of condensation (P=0.019) groups. No significant difference was observed between lateral compaction and System B vertical continuous method (P=0.564).

Conclusion: Based on the results of this study, lateral compaction and system B groups showed higher resistance against the coronal leakage compared with single cone group.