TAREQ HAJAJ, SERBAN TALPOS, CAIUS STOIAN, MEDA LAVINIA NEGRUTIU, CAMELIA SZUHANEK, MALINA POPA,ADRIAN TUDOR STAN, CRISTIAN ZAHARIA, KARIN ROXANA HAJAJ, MONICA LICKER, DELIA MUNTEAN, EMILIA IANES, COSMIN SINESCU DETERMINING THE BIOLOGICAL SEALING QUALITY OF THE IMPLANT-ABUTMENT INTERFACE USING STREPTOCOCCUS MUTANS IN BOTH, CONICAL AND INTERNAL HEX CONNECTIONS A COMPARATIVE STUDY Implants have been around for many years already, having a lot of advantages and high success rates, by some authors even higher than 90%. Nevertheless, throughout the years, problems and failures have occurred in practice which led to bone loss around the implants and even, in some cases, to losing the implant itself. The phenomenon behind this pathological process -peri-implantitis - is believed to be the microleakage which occurs at the implant-abutment interface.This happens due to the existence of a gap present between the implant and the prosthetic abutment. Moreover, the microleakage is amplified because of the, so called, pumo effect. The pump effect occurs when the crown-abutment complex is subjected to occlusal, vertical and oblique, forces. During these micro-movements of the abutment, the microleakage intensifies and the bacteria can easily enter inside the implant, where is impossible to reach and remove through oral hygiene, thus, creating the perfect conditions for peri-implantitis. There are two major types of implant-abutment connections widely used nowadays -internal hex and conical -which are believed to influence the phenomenon and, so, the outcome. In the present study, both types of connections are tested, using Streptococcus Mutans, a common bacteria found in the oral cavity.