International Journal of Periodontics & Restorative Dentistry, 03/1994

This study compared, in a human model, the ability of (1) expanded polytetrafluorethylene (e-PTFE) membranes plus bone-chip autografts, (2) e-PTFE membranes plus demineralized freeze-dried bone, (3) e-PTFE membranes plus a new form of demineralized allograft bone tissue, and (4) e-PTFE membranes alone to enhance bone regeneration around dental implants placed into recent extraction sockets. The histologic results demonstrated that, in humans, guided tissue regeneration techniques are capable of producing new bone osseointegrated with titanium dental implants. Among the graft materials, autogenous bone provided the densest and the greatest amount of bone formation, but use of demineralized freeze-dried bone and a new form of de-mineralized allogenic bone matrix also improved bone regeneration compared to membranes alone after 6 months of healing.

Recent advances in graft procurement and suturing encourage a reassessment of the envelope technique in soft tissue grafting for root coverage. Use of the supraperiosteal envelope permits conservation of existing gingiva, minimal surgical trauma to the recipient area, and firm fixation of the connective tissue graft over single and multiple adjacent areas of recession. The intimate coaptation of the bilaminar soft tissue complex thus achieved may facilitate graft survival and postoperative blending of soft tissues.

There are several techniques that will predictably cover exposed root surfaces; however, most techniques are generally used to treat larger recession areas or sites with inadequate keratinized tissue. The purpose of this study is to evaluate the use of the coronally positioned pedicle graft with inlaid margins in the treatment of shallow recession areas. Utilizing the described technique, 20 isolated Class I defects were treated. Complete root coverage was obtained 95% of the time; the mean root coverage was 98.8%. The procedure resulted in a decrease in sensitivity, the final color and tissue contours of the grafts were excellent, and all patients were satisfied with the results. The coronally positioned pedicle graft with inlaid margins is a simple and predictable method to cover exposed root surfaces in shallow recession areas.

To evaluate the efficacy of guided tissue regeneration around exposed implant threads, 16 implants were placed into fresh extraction sockets in beagle dogs. Polytetrafluoroethylene (e-PTFE) membranes and titanium membranes were used to cover the defects around implants. A control group did not receive any membranes. Results were evaluated histologically. The average gain in bone height was 2.1 mm for e-PTFE sites, 0.8 mm for titanium membranes, and 2.9 mm for control sites. The greatest gain in bone levels was seen for two sites that received e-PTFE membranes and remained covered for the entire evaluation interval. Within the limits of this study, clinical and histologic evidence demonstrated that, when primary coverage is maintained, the use of e-PTFE membranes can significantly enhance bone regeneration around implants.

This paper evaluates the use of guided tissue regeneration for treating 19 pairs of molar grade II furcation defects. Presurgical measurements were taken for the determination of aveolar crestal resorption, vertical open probing attachment, and horizontal open probing attachment. The surgical procedure consisted of sulcular incision, full-thickness facial and lingual flaps, soft tissue debridement, and root planing. One defect from each pair of furcas was treated with an expanded polytetrafluoroethylene membrane, which was left in place for 4 to 6 weeks. Postsurgery soft tissue measurements showed a reduction in probing depth and a gain in vertical and horizontal open probing attachment.

Most studies on marginal adaptation have been performed in vitro; only a few studies have investigated in vivo marginal adaptation and microleakage of crowns. In this study, gold crowns were prepared and cemented on abutments, and their marginal discrepancies were analyzed by scanning electron microscopy according to the impression-replica and cross-section methods. Three observers measured the marginal discrepancies of each crown. Interobserver variance of accuracy was 10 microns by the impression-replica and 15 microns by the cross-section method. The mean values were 124.16 microns by the impression-replica and 129.79 microns by the cross-section method. The two methods tested showed similar results.