Biologic Width around one- and two-piece titanium implants - A histometricevaluation of unloaded nonsubmerged and submerged implants in the canine mandible

Gingival esthetics around natural teeth is based upon a constant vertical d imension of healthy periodontal soft tissues, the Biologic Width. When plac ing endosseous implants, however, several factors influence periimplant sof t and crestal hard tissue reactions, which are not well understood as of to day. Therefore, the purpose of this study was to histometrically examine pe riimplant soft tissue dimensions dependent on varying locations of a rough/ smooth implant border in one-piece implants or a microgap (interface) in tw o-piece implants in relation to the crest of the bone, with two-piece impla nts being placed according to either a submerged or a nonsubmerged techniqu e. Thus, 59 implants were placed in edentulous mandibular areas of five fox hounds in a side-by-side comparison. At the time of sacrifice, six months a fter implant placement, the Biologic Width dimension for one-piece implants , with the rough/smooth border located at the bone crest level, was signifi cantly smaller (P <0.05) compared to two-piece implants with a microgap (in terface) located at or below the crest of the bone. In addition, for one-pi ece implants, the tip of the gingival margin (GM) was located significantly more coronally (P <0.005) compared to two-piece implants. These findings, as evaluated by nondecalcified histology under unloaded conditions in the c anine mandible, suggest that the gingival margin (GM) is located more coron ally and Biologic Width (BW) dimensions are more similar to natural teeth a round one-piece nonsubmerged implants compared to either two-piece nonsubme rged or two-piece submerged implants.