Bone reaction adjacent to microplasma-sprayed calcium phosphate-coated oral implants subjected to an occlusal load, an experimental study in the dog.

BACKGROUND

A new microplasma spraying equipment (MSE) to deposit calcium phosphate (CaP) ceramic coatings onto titanium substrates has been developed. With this system, it is possible to spray fine particles and to apply textured hydroxylapatite coatings onto titanium surfaces. Moreover, due to the low heat power of the microplasma jet, overheating of the powder particles as well as excessive local overheating of the substrate are diminished. Furthermore, because of the small laminar plasma jet, it is possible to achieve high spray efficiency in the case of spraying for dental implants. Also, the low level of noise (25-50 dB) and hardly any dust makes it possible to operate MSE under conditions of normal workrooms.

OBJECTIVE

The aim was to investigate, in a mandibular dog model, the effect of functional load on soft-tissue adaptation as well as crestal bone-level changes around titanium implants provided with newly developed microplasma-sprayed CaP coatings.

MATERIAL AND METHODS

For histomorphometrical evaluation, 56 screw-type titanium implants were inserted into the mandibles of seven adult Beagle dogs. The implants were either acid etched without an additional coating, coated with a conventionally plasma-sprayed CaP ceramic (PS), coated with a microplasma-sprayed CaP ceramic (MPS) or with a microplasma-sprayed coating at only the apical part (aMPS). To assess the effect of occlusal loading, a split-mouth design was used. Six weeks after implantation, the implants in one half of the mandible of each dog were functionally loaded whereas the contra lateral implants served as control. One year after loading, the animals were sacrificed. Soft-tissue dimension as well as marginal bone level were histologically assessed.

RESULTS

Histometric analysis of undecalcified histologic sections included the evaluation of the sulcus depth, the dimension of the junctional epithelium and the connective tissue as well as the first bone-to-implant contact. For MPS-surfaced implants, functional loading was associated with--compared with the non-loaded state--unchanged soft-tissue dimension. Furthermore, the soft-tissue dimension did not differ from the dimensions around non-coated, PS and aMPS implants. Moreover, the first bone-to-implant contact was not significantly altered by functional loading and comparable non-coated, PS and aMPS implants.

CONCLUSION

Within the limits of the experiment, we conclude that, in comparison, functional loading does not affect the marginal soft-tissue response to MPS CaP-coated implants. However, in comparison, functional loading might affect marginal bone response to MPS CaP-coated implants.