Microvascular adaptation to transmucosal implants. A scanning electron microscopic study in the rat.

The profuse gingival microvasculature surrounding natural teeth has a unique architecture that contributes to the biologic seal and the anti‐infective defense in the sulcular region. This study tested the hypothesis that this characteristic vascular arrangement is not replicated when gingival tissues adapt to a transmucosal implant. In 20 4‐week‐old Wistar rats, the upper first molar was extracted bilaterally and the gingiva at this site excised. Four weeks later, a 5‐mm‐long titanium screw was implanted at the extraction site on one side. After another 4 weeks, the rats were injected with liquid plastic resin through the carotid arteries and vascular casts prepared for scanning electron microscopy. The results showed that, within 4 weeks after implant insertion, the microvasculature of the regenerated soft tissues immediately surrounding the implant had formed a characteristic arrangement that consisted of a dense subepithelial network as well as an orderly array of vertically oriented capillary loops. The density and diameter of the capillaries varied within a wide range, possibly related to the extent of healing and/or inflammatory conditions. On the contralateral, edentulous side, the capillaries formed a flattened meshwork showing a conspicuous absence of capillary loops. This study indicates that, when a transmucosal implant is inserted in an edentulous area, the mucosal microvasculature adapts and forms an arrangement very similar to that surrounding natural teeth.