Comparison of the fracture resistance of endodontically treated teeth restored with prefabricated posts and composite resin cores with different post lenghts

OBJECTIVE: This study evaluated the fracture strengths of endodontically treated teeth restored with prefabricated posts with different post lengths. MATERIAL AND METHODS: Thirty freshly extracted canines were endodontically treated. They were randomly divided into groups of 10 teeth and prepared according to 3 experimental protocols, as follows; Group 1/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with post length of 5.0mm; Group 1/2 PP and Group 2/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with different combinations of post length of 7.5mm and 10mm, respectively. All teeth were restored with full metal crowns. The fracture resistance (N) was measured in a universal testing machine (crosshead speed 0.5mm/min) at 45 degrees to the tooth long axis until failure. Data were analyzed by one-way analysis of variance (alpha=.05). RESULTS: The one-way analysis of variance demonstrated no significant difference among the different post lengths (P>;.05) (Groups 1/3 PP = 405.4 N, 1/2 PP = 395.6 N, 2/3 PP = 393.8 N). Failures occurred mainly due to core fracture. CONCLUSIONS: The results of this study showed that an increased post length in teeth restored with prefabricated posts did not significantly increase the fracture resistance of endodontically treated teeth

Comparison of orange oil and chloroform as gutta- percha solvents in endodontic retreatment

Objective: To compare the efficacy of gutta-percha removal achieved with simple mechanical technique using two different solvents.MATERIALS AND Methods: It was an in vitro experimental study conducted at the Aga Khan University Hospital, Karachi, Pakistan on 27 extracted human molars divided into two groups by alternate sampling technique. The teeth were prepared by manual filing and obturated with gutta-percha and calcium hydroxide sealer. Two drops of the assigned solvent were placed on the orifice of the obturated canal and Gates Glidden drills #1, 2 and 3 were used for removal of coronal gutta-percha. Manual filing was done for removal of remaining gutta-percha and the solvent was used in drops until needed. Postoperative periapical radiographs were taken to visualize the remaining gutta-percha left in the canals. Descriptive statistics (mean and SD) of the variables such as tooth type, obturation length and canal curvatures were determined. Chi-square and independent sample t-tests were applied and level of significance was set at 0.05.Results: There was 5.19 (3.8) mm of remaining gutta-percha in the orange oil group and 5.37 (4.2) mm in the chloroform group (p=0.90).CONCLUSION: There is no statistically significant difference between the orange oil and chloroform when used as solvent for removing gutta-percha