The effects of premature exposure on the integration of implants in monkeys. Part 2. Clinical results 6 months after being brought into function

Aim of the study

To evaluate the effect on clinical indices of premature exposure of implants, 6 months after being brought into function. Premature exposure is defined here as occurring when the implant becomes visible within the first three weeks after insertion.

Materials and methods

Forty-eight implants were placed on two sides of the maxilla and mandible of six adult baboons ; 24 CPTi (titanium implants) and 24 Ti-13-13 (titanium, niobium, zirconium). After placement, the heights of the necks of the implants from the bone crest were measured and standardised radiographs taken. The mandibular implants were placed 3 months after those in the maxilla so that they could be brought into function simultaneously. When the implants were exposed, the measurements were retaken and then repeated after 6 months in function. Also, a reeva luation of their stability, using Periotest^®, was undertaken.

Results

After 6 months in function, no statistically significant difference in the level of bone could be found between the CPTi and Ti-13-13 implants. The same was the case for the heights of bone crests, whether the implants were exposed or not. The percentage of implants categorised as having « good results » (from - 7 to - 1 on the Periotest^®) was comparable for the exposed and non-exposed sites.

Conclusion

Equivalent results were obtained for premature exposure of CPTi and Ti-13-13 implants. The clinical parameters for non-exposed implants were better at the time of being brought into function but there was no difference 6 months later. After the implants had been brought into function, a single stage surgical approach gives similar clinical results to the two stage approach.

Commentary

This work adds to the publications concerning single stage surgery for implants. But must we forget the protocol described by the Swedish team ? The results presented do not show a statistically significant difference after 6 months of function. Let us wait for the results after a few more years.