Ultrastructure of the peri-implant junctional epithelium on single-crystal sapphire endosseous dental implant loaded with functional stress.

To elucidate the ultrastructure of peri-implant junctional epithelium (IJE) on single-crystal sapphire dental implants connected to the adjacent teeth by a metal superstructure, the peri-implant gingivae of ten monkeys were examined using a transmission electron microscope (TEM) at 3, 6 and 12 months after implant insertion. At the time of examination, the ultrastructural features of the IJE were almost identical to those of junctional epithelium (JE) attached to natural teeth, i.e. developed Golgi complexes, rough-surfaced endoplasmic reticulum, numerous free ribosomes and mitochondria. The innermost cells of IJE were attached to the implant surface by means of basal lamina-like structures (500-1000 A in thickness) and hemidesmosomes, but lacked a dental cuticle as seen on teeth. Such epithelial attachment of the IJE was often indistinct or absent at the apical portion of the IJE which terminated at the level of alveolar crest. A continuous basal lamina-like structure was also present along basal cells at the interface between the IJE and gingival connective tissue except at its apical portion.