The biomechanical effect of root amputation and degree of furcation involvement on intracoronally splinted upper molar teeth – An in vitro study

Fatigue Resistance of Dissected Lower First Molars Restored with Direct Fiber-Reinforced Bridges—An In Vitro Pilot Study

“…Our results suggest that the amount of periodontal support does not seem to influence the fracture patterns of these bridge units as none of the units in Group 2 (continuous fibers and periodontally compromised situation) fractured during the mechanical testing. This is contrary to our previous findings [ 34 ], when upper maxillary, root-amputated teeth were examined, which could account for the different outcomes.…”

“…Surprisingly, our results seem to suggest that the amount of periodontal support does not play a crucial role in the fatigue resistance when looking at each tested restorative technique, as the groups within a certain restorative technique with different levels of simulated periodontal support did not differ significantly (comparing Group 1 to 2, and Group 3 to 4). This is in agreement with our earlier findings, where we examined the mechanical behavior of root-amputated intracoronally splinted, periodontally compromised maxillary molars and the presence or absence of furcation involvement did not seem to influence the fatigue survival of the tested specimen [ 34 ]. At the same time, these findings contradict those of Soares et al, who found that the amount of bony support influenced the strain that developed in the splinted teeth [ 50 ].…”

“…The sectioned surfaces were smoothened to have a cleansable non-retentive surface. In the hemisected distal tooth halves, the pulp chambers were deroofed and endodontic treatment of the distal canal(s) was performed according to our previous protocol [ 34 ]. The root canals were instrumented with Pathfiles (1-2-3) and ProTaper (S1-S2-F1-F2-F3) (Dentsply Maillefer, Ballaigues, Switzerland) to the working length.…”

“…All units restored in the aforementioned way were embedded in a special methacrylate resin (Technovit 4004, Heraeus-Kulzer, Wertheim, Germany) in the following way: samples of Groups 1 and 3 were embedded in accordance with intact periodontal conditions 2 mm from the CEJ, while in Group 2 and 4, embedding was performed and the level of embedding was set at 6 mm apical to the CEJ, simulating furcation involvement [ 34 , 36 ]. The simulation of periodontal ligaments was achieved with a latex separating liquid (Rubber-Sep, Kerr, Orange, CA, USA), which was applied in one layer to the roots according to the level of the planned embedding, before embedding [ 34 , 37 ].…”