International Journal of Periodontics & Restorative Dentistry, 05/1999

Recent experimental and clinical case reports demonstrated vertical ridge regeneration in atrophic posterior mandibles and maxillae. Although the results from these clinical cases are quite encouraging there is a lack of human histologic data on the newly regenerated tissue around commercially available titanium implants. The aim of the present study was to perform a qualitative and quantitative histologic analysis of the bone response to previously exposed implant threads after treatment with guided bone regeneration in a series of patients. A total of 30 Nobel Biocare implants were consecutively placed in 6 patients with partially edentulous mandibles. Of these implants, 6 were planned for removal after 1 year, whereas the remaining 24 implants were inserted to function as support for a fixed partial denture. The 6 experimental implants were intentionally allowed to protrude occlusally 5 to 7 mm from the bone crest without countersinking. The exposed implant threads were completely covered by autogenous bone chips. After a 12-month healing period the 6 experimental implants were removed with trephine burs. Bone-to-metal contact and bone density in the implant threads were measured. Clinically, all implants were stable and there was complete tissue fill of the space underneath the membranes. Histologically, a substantial amount of new bone had formed underneath the membrane in all cases. Histomorphometrically, there was a lower bone-to-metal contact percentage in the exposed compared to the nonexposed region in every case. With respect to bone density, there was a mean of 43.2% in previously exposed regions compared to 60.3% in previously nonexposed regions.

Connective tissue grafts combined with pedicle grafts (subepithelial grafts) have been shown to be effective in obtaining root coverage. Unfortunately, little is known about the histology of the results in humans. This is a case report of a tooth with a recession defect that was treated with a subepithelial graft. Complete root coverage was obtained. However, at 5 months postoperative the tooth had to be extracted because of a vertical root fracture. With the patient's permission, a small collar of tissue was removed with the tooth. The sample was processed and evaluated histologically. The results revealed areas of regeneration, with new bone, cementum, and connective tissue attachment coronal to the original gingival margin. No bone grafts or guided tissue regeneration membranes were used. This case report confirms that regeneration is possible with subepithelial grafts.

While root coverage is predictable for Miller Class I and II recessions, the surgical regeneration or reconstruction of a lost interdental papilla is more difficult to obtain. To date only a few successful case reports have been reported, and there are no studies that report a predictable technique to obtain papilla reconstruction or root coverage on Class IV recessions. This case report, which is part of a preliminary study, outlines a surgical technique to obtain simultaneous root coverage and papilla reconstruction.

An IMZ titanium plasma-sprayed implant was placed at the time of removal of a fractured mandibular left first premolar. Porous hydroxyapatite (Interpore 200) was placed on one side of the residual defect around the implant, and the entire defect was covered with a Gore-Tex membrane. The implant, with surrounding newly reformed hard tissues, was removed in a block section 13 months postoperative. Histologic examination demonstrated regeneration of living bone tissues, the attainment of osseointegration, and incorporation of the Interpore 200 into surrounding bone.

As a possible alternative to conventional techniques for excavating caries chemomechanical methods have been developed. Caridex has so far been the dominating product. However, a new system, Carisolv, was recently introduced. The purpose of the present study was to evaluate the caries-dissolving efficacy of Carisolv in vitro. After excavation with Carisolv all dentin surfaces were caries free. However, 6 of the 10 cavities showed residual caries in the dentinoenamel junction. The dentin and enamel surfaces were covered by smear and debris. Since there may be a risk of leaving caries in the dentinoenamel junction proper case selection appears to be of importance to ensure a successful result.

A new surgical technique for the treatment of adjacent soft tissue marginal recession is presented. This technique combines the use of a tunnel procedure with double lateral pedicle flaps to cover a connective tissue graft. This approach combines the advantages of the tunnel technique with the increased blood supply and protection provided by pedicle flaps. Indications include adjacent Class I and II deep, wide recessions; however, the procedure may also be applied to mild Class III recessions. Two case reports are presented to illustrate this new technique.

The regeneration of periodontal structures lost to inflammatory disease is an elusive yet attainable goal of periodontal therapy. This article reports the successful treatment of a large periodontal defect using a combination of demineralized freeze-dried bone allograft (DFDBA) and guided tissue regeneration (GTR). The case presents endodontic and mucogingival complications in the combined GTR osseous graft technique. The combined techniques used in this 27-year-old patient achieved a reduction in probing depth, radiographic evidence of bone fill, and a reduction in clinical mobility.

The effect of PerioGlas (synthetic bone particulate) on wound healing of experimental palatal periodontal defects in monkeys was evaluated. Chronic periodontal defects were created on the palatal aspects of maxillary molars and premolars. Open-flap debridement was performed. Experimental sites received PerioGlas, while control sites received no further treatment. Histologic measurements were performed on new bone, new cementum, epithelial downgrowth, and recession. Results showed significantly more new cementum and less epithelial downgrowth in the sites that received PerioGlas (P 0.05). The present results indicate that PerioGlas may enhance periodontal wound healing outcomes.

The aim of the present study was to evaluate clinically and histologically the treatment of intrabony periodontal defects with a bioresorbable membrane barrier. Fifty-two intrabony periodontal defects were treated according to the principles of guided tissue regeneration (GTR) with a bioresorbable membrane. Results were evaluated by assessing probing pocket depth, recession of the gingival margin, and clinical attachment level at baseline and at 1 and 2 years after therapy. Bone level changes were evaluated radiographically. The postoperative phase was uneventful in all cases. There was a mean probing pocket depth reduction from 8.4 to 3.6 mm, a mean increase of gingival margin recession from 1.5 to 3.0 mm, and a mean clinical attachment level change from 9.9 to 6.5 mm. Mean attachment gain was 3.4 mm. Two teeth scheduled for extraction were also treated with the same bioresorbable membrane. The histologic analysis 6 months after treatment revealed the formation of new connective tissue attachment and new alveolar bone in both cases. Based on the histologic findings it can be concluded that the clinical improvements following GTR with this type of bioresorbable membrane may represent, at least in part, true periodontal regeneration.