The technical quality of root fillings placed by undergraduate dental students was classified as 'acceptable' in 23% of cases. There was little difference between 4th- and 5th-year students in the overall quality of root fillings.

The attachment and morphology of human periodontal ligament fibroblasts to mineral trioxide aggregate (MTA) was evaluated using a scanning electron microscope. The material was placed at an apical cavity of 30 single-rooted slices of extracted human teeth. The specimens were divided into two groups of 15 root slices each (freshly mixed and set state). For each experimental group, five root slices were used per observation period (4, 8, and 24 h). A set of two glass slides was used per observation period for the control group. The experiments were performed in tissue-culture cluster 96-well plates in which 1 ml of human periodontal ligament fibroblast cell suspension was placed over the MTA filling and the control glass slides. For the positive-control group, 0.5 ml of methyl methacrylate 2% (vol/vol) was added to the cell suspensions before being dispensed into the wells. Results showed the normal cell morphology in the negative controls. Few round cells with less smooth surfaces and many rough blebs were seen in the positive control, and most of these cells did not show any attachment to the substratum. Similar observations were seen with the freshly prepared-MTA group. In the set-MTA group, cells were round and flattened, displayed smooth surfaces, and appeared to be tightly attached to MTA. It was concluded that the quality and quantity of cell attachment to the retrofilling material could be used as a criterion to evaluate material's toxicity. This research (FN#1077) is registered with the College of Dentistry research center, King Saud University, Riyadh, Saudi Arabia. The author thanks the administration of the King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, and in particular Dr. M. N. Al-Ahdal for providing the use of the Molecular Virology and Infectious Disease Laboratory, Mr. Yunus Siddiqui for his support, and Dr. Saad AL-Nazhan for his assistance in preparing the manuscript.

No abstract

This in vitro study evaluated the microbial leakage of Cavit, IRM, and Dyract when used as temporary filling materials after root canal treatment. The degree of coronal leakage was assessed by using a microbiological marker consisting of Streptococcus faecalis and Candida albicans. For each of the two organisms, a set of 15 maxillary premolars were prepared chemomechanically and obturated with thermoplasticized gutta-percha. A 3.5-mm thick layer of one of the three temporary filling materials was inserted in the access cavities of the teeth from each group (each group was compromised of five teeth). The control teeth (four positive and four negative) lacked any filling material over the gutta-percha, whereas the orifice and the apical foramen of the negative control were completely sealed with nail polish. Each tooth was placed in a well of a 24-well tissue culture plate and embedded in trypticase soy broth and 0.5% Bactoagar. An organism suspension was inoculated in the access cavity, and microbial penetration was detected as an increase in turbidity of the broth. At the end of 30 days, the results showed that all positive control teeth leaked within 1 week, whereas those that served as negative control remained uncontaminated throughout the test period. With both organisms, IRM started to leak after 10 days, whereas Cavit and Dyract leaked after 2 weeks.

Ethanol and hexane extracts of were found to exhibit maximum antimicrobial activity against, and at high concentrations.