In vivo performance of a modified CSTi dental implant coating.

Cylindrical dental implants coated with cancellous structured titanium (CSTi) were studied in a dog model. CSTi-2-coated and hydroxyapatite-coated (HA) implants were placed in 8 mongrel dogs. The porosity of the CSTi-2 coating was 9% less than that of the previously studied CSTi-1, resulting in greatly improved mechanical strength and cosmetic appearance. A slightly lower level of bone ingrowth was observed for CSTi-2 than for CSTi-1. However, the in vivo attachment strength of the CSTi-2 coating was comparable both to CSTi-1 and to an HA-coated control after 8 weeks. Measured porosity is technique dependent; digital analysis of in vitro samples yielded higher porosity values than in vivo histology cross sections.

Preliminary evaluation of titanium-coated PEEK dental implants.

A total of 40 titanium-coated and uncoated polyetheretherketone (PEEK) cylindrical implants was placed in unicortical sites in the femurs of four mongrel dogs. The implants were evaluated mechanically and histologically at periods of four and eight weeks. Interface attachment strength was determined for each specimen, as were measurements of bone contact, porosity, bone ingrowth, inflammatory response, and mode of failure. Statistical analysis revealed that the uncoated implants had a significantly higher interface shear strength at four weeks, but that there was no significant difference from the coated implants at eight weeks. At both four and eight weeks, the titanium-coated specimens had significantly higher percentages of bone contact. There was no significant increase in bone contact between four and eight weeks for either the coated or uncoated specimens.

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.

In vivo evaluation of a CSTi dental implant: a healing time course study.

The in vivo interface attachment strength and histology of CSTi (cancellous-structured titanium)-coated cylindrical dental implants were compared with those of solid HA-coated dental implants of the same dimensions and geometry. The implants were placed in healed extraction sites in the mandibles and prepared unicortical sites in the femurs of canines. The mandibular implants were evaluated at two, four, eight, and 12 weeks post-implantation, and the femoral implants were evaluated at two, four, eight, 12, 16, 24, and 34 weeks post-implantation. The interface attachment strength of the CSTi implants placed in the mandible at two, four, eight, and 12 weeks was not significantly different from that of the control HA-coated implants. In the femurs, the CSTi implants were significantly stronger than the HA-coated implants at all time periods except 12 weeks (two, four, eight, 16, 24, and 34 weeks). The CSTi implants were able to achieve high percentages of bone ingrowth in the mandible and femur of up to 92% at the later time periods, thus providing a sound interface bond.