In vivo evaluation of CSTi dental implants in the presence of ligature-induced peri-implantitis.

The histology of a CSTi (cancellous-structured titanium) porous-coated cylindrical dental implant was compared with that of a solid control HA (hydroxylapatite)-coated dental implant with the same geometry. A particular concern with the use of porous-coated implants in dental applications is the possibility of infection due to direct exposure to the outside environment. Three implants of each type were placed in healed mandibular sites of 14 canines, and after eight weeks of healing, an abutment was placed on each implant. In one half of the implants, ligature-induced peri-implantitis was introduced. The implants were evaluated at four, eight, 16, and 26 weeks post-ligature placement. Bone ingrowth percentages were relatively high for both ligated and non-ligated CSTi specimens, with mean values ranging from 59% to 71%. There was no significant difference in bone ingrowth percentages between ligated and non-ligated specimens at any of the evaluation periods. For the HA-coated specimens, there was also no significant difference in bone contact percentages between ligated and non-ligated implants. There was not a significant decrease in bone contact of bone ingrowth with time for either the ligated or non-ligated implants. No loss of bone along the porous coating or coating-bone interface was observed due to the peri-implantitis, although HA failure was seen primarily in ligated specimens. When crestal bone loss was evaluated on histologic sections and radiographs, it was found that there was no significant difference in loss between CSTi- and HA-coated implants at all time periods for ligated and non-ligated specimens. Histological inspection of the CSTi implants did not reveal any migration of infection or inflammation through the porous coating resulting in bone ingrowth loss.