External versus internal abutment connection implants: a survey of opinions and decision making among experienced implant dentists in Japan.

Internal connection implants have been attracting attention in recent years leading to their being adopted for many implant systems and an increase in market share over other connections. However, internal connection implants have only been used clinically for a short period of time resulting in few clinical studies investigating outcomes and a lack of comparative clinical evidence to support their use over external hex systems at this time. Given the fact that clinical evidence is lacking regarding implant connection performance comparisons, it is important to understand what information clinicians use to choose between systems. The purpose of this study regarding implant decision-making was to ask clinicians to provide subjective evaluations of internal connection implants, in comparison with external connection implants. The survey was constructed to cover four aspects of interest; general responder information, surgical procedures and experience, prosthodontic treatments and outcomes, and implant complications. The dentists' responses indicated that internal connection implants are as user-friendly as external hex implants with respect to implant surgery, but they are favored for prosthodontic handling because impression coping and abutment placement are felt to be easier. In addition, it was revealed that dentists strongly feel that there is a lack of biological and prosthodontic evidence to support the use of internal connection implants. The findings reveal the responding clinicians recognize that they often make decisions without compelling evidence to favor one system over another. Decisions are often based on perceived ease of use or third party (colleague or manufacturer) input. For future investigations, we will seek to better understand the relative influence and validity of all forms of information used (especially third party input), as well as what barriers exist to clinicians' use of more evidence based data.