Influence of single post, oval, and multi-post restorative techniques and amount of residual tooth substance on fracture strength of endodontically treated maxillary premolars. Spiccarielli V., Marruganti, C., Di Matteo C., Martignnoni M., Ounsi H., Doldo, T., Ferrari, M., Grandini, S. J Oral Sci 2021;63.

Purpose: The aim of this study was to compare the influence of the number of coronal walls and post-endodontic restorations on the mechanical strength of 165 recently extracted endodontically treated maxillary premolars.

Methods: The teeth were divided into 3 control (no post) and 3 test groups according to the number of residual walls. Each test group was divided into subgroups according to the type of post-endodontic restoration (single, oval, and multi-post techniques). Samples were prepared conforming to the assigned subgroup. A universal loading machine applied a load parallel to the longitudinal axis of the teeth, thus simulating physiological occlusion. ANOVA and the Kruskal Wallis test were used for comparisons (P ≤ 0.05), and Tukey’s test for multiple comparisons.

Results: For intact teeth, significant differences were found among all 3 subgroups, with single post showing the highest values. For 3 residual walls, oval post resulted in significantly lower values than single and multi-post systems. For 2 residual walls, the multi-post technique showed almost twice the resistance of oval post restorations.

Conclusion: In oval canals the use of a single or multi-post technique increased post-and-core resistance even in intact teeth, whereas oval fiber posts showed no improvements. Multi-post design improved fracture resistance mostly in maxillary premolars lacking both marginal ridges.

Prof. Hani Ounsi graduated from the School of Dental Surgery, University of Montpellier, France. He holds a post-graduate degree in Endodontics, a Master in Medical and Biological Sciences, a Research Masters degree in oral biology from Saint-Joseph University in Beirut where he taught Endodontics. He received his Ph.D. in Dental Materials from the University of Siena. Prof. Ounsi is Assistant-Professor at the Department of Endodontics of the Lebanese University and visiting professor at the Department of Endodontics and Restorative dentistry of Siena University. He is fellow of the International College of Dentists and member of the European Society of Endodontology and the American Association of Endodontists. He authored and co-authored more than 40 publications, and presented and conducted more than 150 lectures, conferences, and courses in 5 continents.