Frameworks and veneering materials in posterior dental arches rehabilitation, a bio-faithful mechanical simulation: a post-testing analysis

OBJECTIVES: to evaluate differences in the ultimate fracture resistences of three different materials ( peek .composite/ zirconium-ceramic/ laser sintering-ceramic) in fixed partial dentures, realized upon two fixtures embedded in glass-fibers, reinforced resin mandible simulator in order to recreate a bio-faithful system. MATERIAL AND METHODS: Twenty titanium fixtures ( Sweden & Martina® ) were embedded in 20 resin mandible section simulators to mimic osseointegrated implants in the first premolar area and molar area. The embedded implants were then divided into three groups: Group A: five Fixed Partial Dentures (FPD’s) in peek –composite connected to titanium abutments, Group B: five FPD’s in laser sintering ceramic connected to titanium abutments, Group C: five FPD’s in zirconium-ceramic connected to titanium abutments. Groups were loaded in a dynamometric testing machine (Instron 5566 , UK) adopting the three point bending mechanical tests configuration. The cyclic load applied to the structures ranges from a minimum of 0 N to a maximum of 860N. A vertical load of 860 N was applied on each sample with a sinusoidal fashion. A strain gauge (C-980204, Micro-oup Inc., Raleigh, NC, USA: Omicron-T, Battipaglia, ITALY) was applied on the buccal and lingual surface of all tested in order to evaluate structural deformation of three materials. Samples showing macroscopic failure were analyzed by scanning electron microscopy (SEM) and micro-tac afterby the mechainical loading. ESSENTIAL RESULTS: Laser sintering samples didn’t incur in any failure during testing phase , peek composite samples in only one failure, while four zirconium ceramic samples incur in chipping and one in total fracture. Chippings are concentrated near the inner margin of abutments. From SEM analysis of the specimens’ fragments zirconium-ceramic analyzed after test equipment, it is difficult to highlight a clear margin and no-adhesion zones between the two materials . Analysing zirconium we are in the presence of a cohesive failure. Bubbles inside composite structure are the only significat structural defects revealed to Micro TC. CONCLUSION: Is advisable to adopt laser sintering framework with feldispatic ( rich in leucite)veneering and peek framework with composite veneering for rehabilitation of the lateral-posterior region of mandibular arch.