Читать книгу Periodontics - Fernando Suarez - Страница 22

The replacement and restoration of the missing dentition by means of dental implants has become a routine procedure in daily practice. As such, a plethora of systems with different macro- and microstructures are available on the market. However, independently of the design, the proper functioning of dental implants is primarily based on the process of osseointegration. This phenomenon is defined as the direct contact between the surface of a loaded implant and vital bone.

Considerable differences exist between the structures giving support to dental implants and natural dentition, the most important being the lack of PDL for osseointegrated implants. However, at the most coronal portion, some similarities can be found. Similar to the supracrestal attached tissues in the natural dentition, implants also present in their most coronal portion with a sulcus epithelium, junctional epithelium, and connective tissue.³⁵ In 1991 in an animal model, Berglundh et al³⁵ described the differences in the arrangement of collagenous fibers in the connective tissue between teeth and implants. Essentially, while the collagenous fibers run perpendicular to the axis of the tooth, they run parallel to the surface of an implant. The composition of the connective tissue also seems to differ between implants and teeth. As such, more collagen and fewer cells have been found around dental implants in comparison with teeth.³⁵ Moon et al³⁶ also described that although generally a reduced number of cells have been found in the periimplant tissue, a cell-rich zone is present in the connective tissue adjacent to the implant-abutment surface with high concentration of fibroblasts.

The absence of PDL space around dental implants also determines the lack of vascularization from this structure. Consequently, the blood vessels that irrigate the periimplant mucosa are terminal branches from the periosteum. On the other hand, both natural dentition and dental implants present with a vascular plexus adjacent to the junctional epithelium.³⁷