UNIVERSIDADE DE SÃO PAULO FACULDADE DE ODONTOLOGIA DE RIBEIRÃO PRETO SÉRGIO ROCHA BERNARDES Avaliação mecânica da estabilidade de parafusos protéticos em diferentes sistemas de retenção pilar/implante. RIBEIRÃO PRETO 2008 1. implante dentário, 2. interface pilar/implante, 3. pré-carga, 4. torque, 5. parafuso. Ao Prof. Dr. Figueiredo (Fig) pela simpatia e importantes conselhos dados durante os "créditos-cafés" ministrados em Londres. Um grande representante brasileiro em terras estrangeiras. A empresa Neodent (Curitiba, Brasil) e seus funcionários pela confiança e ajuda material única, sem a qual o trabalho não seria realizado. A todos os funcionários e docentes do Instituto Latino Americano de Pesquisa e Ensino Odontológico/ILAPEO, por todo o apoio durante o período de ausência. À Eastman Dental Institute/University Collegue London, pelo aceite e disponibilidade para realização do estudo. Para a Faculdade de Odontologia de Ribeirão Preto/Universidade de São Paulo, funcionários e docentes pela disponibilidade oferecida durante o curso.Pelo apoio financeiro concedido pela Fapesp (06/60688-2) para aquisição de todo material utilizado na pesquisa e para a Capes, pelo apoio financeiro durante o estágio internacional. The preload screw variation for the first five minutes after each one of five torque/untorque sequences from different implant/abutment retention systems was evaluated. Strain gauges were attached over the cervical third of external hex, internal hex and Morse taper implants. A controlled torque/untorque procedure allowed the record from the preload and untorque values of the samples in each one of the sequences. Thirty implant/abutment samples, divided in eight groups were studied: external hex implants with Universal post and titanium screws (Neodent, Curitiba, Brazil) screwed to 32 N.cm (EH.Ti.32); external hex, Universal post, DLC covered screw, 32 N.cm (EH.dlc.32); Universal post trespassing screw, 10 N.cm (MT.TS.10); the same samples from the MT.TS.10 group were used for the seventh group, screwed to 10 N.cm, but the untorque was performed by the abutment (MT.TS.10.A); the same samples used with the MT.TS.10 and the MT.TS.10.A were used for the last group, but the screws were tightened to 15 N.cm and the untorque remained by the abutment (MT.TS.15.A). The mean and the stardad deviation (DP) found for the preloss in all the five sequences were of: EH.Ti.32 (27.75; SD 7.70); EH.dlc.For the retention systems studied, it could be concluded that: there are single relations between screw untorque and preload over the implant cervical third, these are directely influenced by the implant/abutment interface design, screw type and torque value; there were not found post screw preload loss, neither torque resistance at the anti-rotational direction from the screws after the first five minutes in five torque/untorque sequences.