Repair following treatment of circumferential periodontal defects in dogs with collagen and expanded polytetrafluoroethylene barrier membranes.

This study was designed to evaluate healing following treatment of periodontal defects using 2 collagen barrier membranes with different degrees of cross-linking, and to compare the results to those following use of an expanded polytetrafluoroethylene (ePTFE) membrane. Horizontal, circumferential defects were created in mandibular premolar teeth of 6 beagle dogs, followed by placement of membranes and wound closure. Postoperative healing was monitored clinically for 6 months, at which time the animals were sacrificed and specimens were taken for histological examination. Clinical observations indicated that the highly cross-linked, slow-resorbing collagen membrane did not integrate with the tissues the way the less crosslinked, rapid-resorbing collagen did. Membrane exposure was typical for the slow-resorbing membrane in contrast to the rapid-resorbing membrane which remained covered. The inferiority of the slow-resorbing membrane was evident by the extensive clinical recession and the attachment level measurements taken at 6 months, and it was decided to omit this membrane from histometric analysis. Histological examination of root surfaces treated with rapid-resorbing collagen or ePTFE membranes revealed substantial reparative healing. The connective tissue repair amounted to 84% of the treated root surface height for the rapid-resorbing collagen and 53% for the ePTFE membrane (difference not statistically significant). However, the connective tissue repair to the rapid-resorbing collagen group root surfaces was often associated with a layer of ankylosis (44%, versus 8% of the ePTFE group). It appeared that much of the ankylotic response was initiated from the furcation area and extended around to the buccal and lingual surfaces. In addition, this study provided histological evidence that granulation tissue forming under clinically exposed and plaque contaminated ePTFE membranes can still result in connective tissue repair. It was concluded that the rapid-resorbing collagen membranes and the ePTFE membranes seem capable of stimulating periodontal connective tissue repair, whereas the slow-resorbing collagen membranes were unsuccessful in this effort, as seen in this dog model.

The effect of hygiene instruments on dentin surfaces: scanning electron microscopic observations.

The present study consists of two separate parts. The first section is an in vitro evaluation of the relative abrasiveness of some hygiene instrumentations commonly used during maintenance therapy. In the second section, one of the instruments, a recently developed plastic tip for use on a sonic scaler, was examined for its ability to remove dental plaque from root surface specimens instead for 5 weeks in the oral cavities of dogs. The in vitro study was performed on recently obtained dentin specimens where a ridge had been machined parallel to the long axis of the tooth. The sonic scaler fitted with the plastic tip gave considerably less removal of dentin and a smoother dentin surface than the curet, the rubber cup with polishing paste, or the sonic scaler with an ordinary metal tip. These findings further demonstrated that the plastic tip was able to efficiently remove 5-week old dental plaque from experimental root surface areas within a time frame of 5 seconds. The new plastic tip may be valuable in maintenance therapy giving less risks for iatrogenic effects on the root surfaces than other debridement methods.

Coronally displaced flaps in reconstructive periodontal therapy.

This article reviews the approach taken by the Loma Linda University Group in treating molars with Class II and Class III furcation lesions. The surgical technique used is detailed for Class II furcations. The modification of the technique for lingual furcation of lower molars and the postsurgical behavior of a crown-attached flap are also discussed.

Treatment of periodontal furcation defects. Mandibular class III defects.

Twenty-seven mandibular class III furcation defects were treated in 27 subjects using a regenerative therapy that included citric acid root conditioning and coronally positioned flaps secured by crown-attached sutures. In addition to this therapy, 13 of the 27 defects received freeze-dried, decalcified allogenic bone grafts. The effect of these therapies was evaluated from soft tissue probing measurements, including furcation probings to determine soft tissue closure of the defects. At 6 months postsurgery, the mean vertical probing depth reduction and the mean probing attachment level gain in the furcation area were 2.6 mm and 2.2 mm for the non-grafted defects and 1.9 mm and 1.5 mm for the grafted defects. One of the 14 non-grafted defects and 3 of 13 grafted defects were judged to show soft tissue clinical closure by a panel of 3 independent examiners. No statistically significant differences were observed between defects treated with or without bone grafts.

[Regenerative therapy of interradicular lesions. Review of the literature]. / Thérapeutiques régénératrices des lesions interradiculaires. Revue de littérature.

The short and mid-term regenerative therapy in the furcation lesions seems to be promising. The aim of this review is to describe different technics used today. The limits of this therapy, the gain of bone level and/or gain of attachment level and the complementarity of their biological principles are discussed.