The purpose of this laboratory exercise was to describe the fabrication of an in vitro model, containing natural teeth, for teaching the principles of conventional endodontic procedures to preclinical dental students. Maxillary and mandibular models were made (from moulds using silicone duplicating material with U-shaped lingual/palatal groove) from acrylic mixed with saw dust. Apices of the selected teeth were covered with beading wax and placed in the corresponding sockets of the rubber mould before pouring the acrylic.

 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.

In the recent years, news interviews have attracted several researchers to study issues that are related to this expanding field. Many scholars have stated that both interviewers and interviewees should adhere to the turn-taking system of the news interviews. Interviewers therefore are expected to ask questions whilst interviewees should limit themselves to answer these questions. It has been observed however that many interviewees attempt to evade the answers by various ways.