Journal de parodontologie最新文献

A more or less important alveolar gap is often seen after the surgical treatment of clefts. The connective tissue autograft corrects the functional and aesthetic defect of the residual lesion and a fixed prosthetic restoration can be realized.

A patient with adult periodontitis was treated for a 2 and 3-walled intrabony lesion on tooth n degrees 27. After scaling and root planing, the defect was surgically exposed and filled with a micro-porous resin. Following healing, there was a reduction in pocket depth as a result of gingival recession and a gain in probing attachment levels. This was confirmed 13 months post-operatively by clinical observation on re-entry. A biopsy of the treated site was taken at that time and undecalcified sections were studied by light microscopy and microradiography. New bone formation was noted inside and on the surface of the resin granules and at a distance from the particles. From a clinical and histologic point of view, the material seemed to be well tolerated by the host.

The effect of various types of synthetic hydroxyapatites (HA), coated or not with collagen or human plasmatic fibrin, has been studied after 3 month implantation either in freshly extracted alveoli in miniature pigs or in experimentally induced periodontal lesions in beagle dogs. The best histological results were observed in HA without organic coating. The Bioapatite consisting in crystals with a mean size of 146 nm +/- 47 nm were well integrated in the alveolar bone. Similar results were obtained with micro-sized hydroxyapatite, with a mean crystal size of 38 nm +/- 16 nm. But at 3 months, this HA type was still actively integrated in bone with osteogenesis. When these 2 types of HA were coated with collagen or plasmatic fibrin, they were less well incorporated in alveolar bone and were even able to develop localized and moderate inflammatory reactions. The main purpose of synthetic HA is to promote alveolar bone formation in periodontal lesions. For an improved tissular regeneration, it is recommended to use simultaneously in the future synthetic HA together with resorbable biocompatible synthetic membranes.

Destructive periodontal diseases are characterized by tissue breakdown partly mediated by various enzymes originating from bacteria and/or tissue. Collagen and fibronectin are two of the main substrates available for enzyme activity. Since chlorhexidine is largely used during and after periodontal therapy, we have investigated the effects of chlorhexidine upon some bacterial proteases. Our data indicate that chlorhexidine inhibits, on a dose-dependent manner, both fibronectin and collagen hydrolysis mediated by either bacteroides (porphyromonas) gingivalis or bacteroides intermedius. Thus, it might be hypothesized that a side from its bactericidal activity, chlorhexidine helps to prevent periodontal tissue destruction directly by enzyme inhibition.

During the past ten years, biotechnical and scientific advancements in periodontics have improved our knowledge concerning healing (with the concept of guided tissue regeneration) and bone filling (with the new available materials). A combined therapy using both Gore-Tex membranes and Biocoral 450 seemed well indicated for the treatment of an advanced adult periodontitis case. Histological observation of healing tissue biopsy has provided interesting findings concerning coral and cell behavior during the early stages of healing. Besides the slow resorption of the coral, early intrafibrillar calcification processes seem to occur, thus enhancing the regenerative potential.

A resorbable mesh (Polyglactin 910) coated with collagen was employed to test its biocompatibility and its possible role in new attachment procedures.

Although there is no scientific data to support the concept, it is proposed that a band of attached gingiva around implants is clinically desirable. This can be accomplished by the use of gingival grafts either at the time of the second operation or at a later date. This seems preferable to mucogingival surgery performed before implants insertion.

The experience with dental implants has been so satisfactory so as to suggest their usage beyond the limits of their normal indications. Preoperative examinations have been improved by the use of the scanner. The employment of "Scanlam" models simplifies and enhances the interpretation of scanner negatives. By repositioning the surgical guide on the "Scanlam" model, both surgical and prosthetic teams are aided. It should be noted, however, that "Scanlam" models have limitations and are simply volumetric expressions of the scanner. The use of the drilling guide should be used to assist the surgeon, but not to replace his clinical judgement.

Failure of osseointegration and mechanical accidents are the most common complications of dental implants. The functional prognosis is preserved in any case. Most of these complications can be avoided by a careful patient selection, a strict surgical phase and restorative procedures realized by competent practitioners.