Journal of Dental Medicine

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: Angiogenesis plays a central role for development and progression of malignant tumors.It is considered as an important factor for predicting of malignant tumor's behavior such as metastasis to lymph nodes and other clinicopathologic factors. However , it is still a controversial factor especially in oral squamous cell carcinoma.The aim of this study was to evaluate the correlation between angiogenesis and clinicopathologic parameters such as presence of metastatic cervical lymph node in the tongue squamous cell carcinoma.

Materials and Methods: In this cross-sectional study, 40 cases of squamous cell carcinoma of the tongue were selected from the archive of cancer institute of Tehran University of Medical Science. Sections were prepared from paraffin blocks and immunohistochemically stained with antibody against CD34. Stained vessels were counted in 4 fields ,the most vascular areas at low magnification, in each areas of intratumoral ,peritumoral and nontumoral adjacent tissue in two groups with metastatic lymphnodes (N+) and without (N-). The average counts from the four most vascular areas were recorded as the mean microvascular density (MVD). Data were analyzed by 3wayANOVA and Independent T- test with p<0.05 as the level of significance.

Results: High mean MVD-CD34 was significantly correlate with positive cervical lymph node metastasis in intra tumoral and peritumoral areas but there was no significant correlation between mean MVD-CD34 and age, gender, and differentiation of tumor.

Conclusion: Based on the results of this study, CD34 can help us to determine the presence of cervical lymph node metastasis and may also determine the outcome of a primary squamous cell carcinoma of the tongue.

Background and Aim: A considerable percentage of failure in Endodontic treatments in maxillary molars is attributed to undiscovered second mesiobuccal canal (MB₂).There are different methods for discovering and accessing to this canal. The purpose of this ex vivo study was to compare the detection ability of three methods (direct look, fiberoptic loup and surgical microscope) to find MB₂ after troughing with ultrasonic.

Materials and Methods: In this experimental study, we selected 90 extracted maxillary molars (45 first and 45 second molars) in which after access cavity preparation MB₂ canal was not discovered by direct vision and endodontic explorer. They were divided into 3 groups (n=30). The dentinal shelf between mesiobuccal and palatal canals was eliminated by an endodontic ultrasonic tip (troughing). After that, first group was searched by direct vision, second group by a loup and fiberoptic light and third group by dental operating microscope. Data were analyzed, specificity and sensitivity were calculated.

Results: The results showed that 21%, 61%, and 92% of MB₂ canals after troughing was found by direct vision, fiberoptic loup, and surgical microscope, respectively.

Conclusion: Based on the results of this study, surgical microscope and loup with fiberoptic are preferred methods for discovering MB₂ canal. Troughing with ultrasonic can help find MB₂ canal in all methods.

Background and Aims: Considering advantages and disadvantages of mineral trioxide aggregate (MTA), Calcium Enriched Mixture (CEM) cement has been developed recently. The purpose of this study was to compare the apical microleakage of the root-end cavities prepared by ultrasonic or Er,Cr:YSGG laser and filled with MTA or CEM cement.

Materials and Methods: Eighty single-rooted, extracted human teeth were instrumented and obturated. Root-end resection was made by removing 3 mm of the apex. The teeth were randomly divided into two experimental (n=30) and two positive and negative control (n=10) groups. After that, the retrograde cavities were prepared using ultrasonic or Er,Cr: YSGG Laser. According to the root-end filling materials (MTA or CEM cement), each group was then divided into two subgroups. Finally, specimens were cleared for assessing the amount of apical dye (Indian ink) penetration. The data were analyzed using Kruskall-Wallis and Dunn tests.

Results: Laser/CEM cement group showed significantly the lowest mean apical dye penetration. There were no statistically significant differences between Laser/MTA, ultrasonic/MTA and ultrasonic/CEM cement groups.

Conclusion: Based on the findings of this study, CEM cement demonstrated lower rate of apical leakage compared with MTA, when the root-end cavities prepared with Er,Cr:YSGG Laser. The sealing ability of MTA was not different following root-end preparation by ultrasonic or Er,Cr:YSGG Laser.