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The relationship between radiographic crestal alveolar bone mass and changes in clinical periodontal attachment level following guided tissue regeneration (GTR) was evaluated in this retrospective study. A total of 12 intrabony two- or three-walled defects and 12 adjacent nondiseased proximal sites in 10 nonsmoking adult subjects received subgingival debridement and GTR using resorbable (Resolut; five sites) or nonresorbable (Gore-Tex; seven sites) barrier membranes. At a mean of 48.8 months posttreatment, clinical periodontal attachment level alterations were measured, and crestal alveolar bone mass changes on digital subtraction radiographic images derived from serial periapical radiographs were analyzed to correct for between-film geometric and contrast density differences. Intrabony defects exhibited a mean clinical periodontal attachment level gain of 2.3 +/- 0.4 mm, in contrast to a mean loss of 0.5 +/- 0.2 mm in adjacent nondiseased interproximal sites. Digital subtraction radiography revealed an increase in crestal alveolar bone mass at all intrabony sites treated with GTR and a decrease in three of the adjacent nondiseased sites. Site-based analysis yielded an odds ratio of 36 (P < .001) for the association between radiographic increases in crestal alveolar bone mass and clinical periodontal attachment level gains of > or = 2 mm. These results suggest a strong concordance between digital subtraction radiographic assessments of crestal alveolar bone mass and clinical periodontal attachment level in evaluating the long-term effects of GTR at human interproximal intrabony defects.

The last decade has seen an increasing number of clinical reports on guided tissue regeneration (GTR) for reconstruction of gingival recession defects. This article reviews the value of GTR in the management of gingival recession defects based on records from such reports. Studies and case-series using nonresorbable and bioresorbable membranes, studies comparing GTR to the subepithelial connective tissue graft (CTG) procedure, and histologic reports of healing following GTR, published in the English language from 1985 to 2000, were identified using a Medline search and were included in the data-base for this review. The Following pre- and post-treatment data were collated and evaluated for each of the reports: gingival recession depth, probing depth, clinical attachment level, and width of the keratinized gingiva. In perspective of the limitations of the studies reviewed, it has been shown that GTR may be used for reconstruction of gingival recession detects. Importantly it has not been shown that GTR provides an added clinical benefit for the patient treatment planned for reconstruction of gingival recession defects. i.e. GTR does not appear to offer a significant advantage over mucogingival procedures such as the connective tissue graft or the advanced flap procedure. It is imperative to recognize inherent technical difficulties associated with GTR including primary would closure and secondary membrane exposure: membrane exposures being negatively correlated to desired clinical outcomes. Also, membrane exposures appear consistently more common in smokers than in non-smokers. It is also imperative to recognize shortcomings and adverse effects including space maintenance and unacceptable foreign body reactions associated with some bioresorbable GTR technologies.

Combining platelet-rich plasma (PRP) with autogenous bone graft materials has recently been advocated as a means of enhancing rate and quality of new bone formation in regenerative procedures. The aim of this case series was to evaluate the potential of PRP in combination with bone allograft to enhance bone regeneration in alveolar ridge defects exhibiting both vertical and horizontal loss prior to the placement of dental implants. Augmentation resulted in clinical and radiographic gains in both vertical and horizontal components of the osseous defects, thereby facilitating subsequent placement of dental implants. Histologic evaluation of the cases revealed the presence of residual allograft particles surrounded by connective tissue as well as newly formed bone within the grafted areas. However, the addition of PRP did not appear to enhance the quality or quantity of new bone formation over that reported in comparable guided bone regeneration (GBR) studies without PRP.

The results of these studies show that rhBMP-2 clearly enhances regeneration in periodontal defects (Figures 2&3). The extent of regeneration appears to be significantly influenced by the nature of the carrier material used to deliver the rhBMP-2 to the periodontal wound. While the positive effects of rhBMP-2 on osteogenesis are well established, less is known about the way in which rhBMP-2 effects cementogenesis, or its role in the formation of a new periodontal ligament. From the studies reviewed, it would appear that rhBMP-2 facilitate in the formation of cellular cementum on previously denuded root surfaces. This newly formed cementum has also been shown to support an organised periodontal ligament attachment. Mechanisms related to the possible role of rhBMP-2 in ankylosis are presently unclear and will require further investigation as such sequelle may complicate the clinical utility of rhBMP-2 in periodontal regeneration. Root resorption has also been reported in the above mentioned studies and appears to be related to the concentration of rhBMP-2. Further research directed at understanding how different carriers influence the way in which the rhBMP-2 is released during wound healing should assist researchers with how to best apply these bioengineered proteins to ultimately achieve a more predictable regeneration of the periodontal attachment apparatus. Moreover, additional research into the differing biologic effects of other members of the BMP family of proteins may also hold further promise in the application of this technology to periodontal regeneration.

Diagnosis of combined periodontal-endodontic lesions can prove difficult and frustrating. They are often characterised by extensive loss of periodontal attachment and alveolar bone, and their successful management depends on careful clinical evaluation, accurate diagnosis, and a structured approach to treatment planning for both the periodontic and endodontic components. Recent advances in regenerative periodontics have led to improved management of periodontal-endodontic lesions. This paper reviews the management of such lesions in light of these recent advances and illustrates this through reports of two patients who had severe periodontal involvement.

The purpose of this study was to evaluate the sheep as a suitable animal model in which to compare periodontal wound healing after surgically induced Class II furcation defects were treated with different guided tissue regeneration (GTR) membranes. 22 mandibular second premolar sites in 11 sheep were used. The experimental design included untreated control teeth, sites treated by surgery alone, and others where surgery included placement of either Gore-Tex Periodontal Material (GTPM) or Gore-Tex Soft Tissue Patch (GTSTP). Sheep were killed 7 wk after surgery. Mesiodistal sections through decalcified second mandibular premolars were evaluated histologically. Histomorphometric analysis of digitized images allowed both area and linear measurements of newly regenerated furcal tissues. Percentage areas of cementum, bone, epithelium and connective tissue filling the furcation region were calculated. Coronal regeneration of alveolar bone and cementum were expressed as a percentage of the original height of the defect. Mean values for each group were subsequently analysed by 1-way ANOVA. Significantly greater regeneration was achieved with both of the GTR membranes, by comparison with the non-GTR surgical control group, with respect to percentage areas of cementum, bone and connective tissue, and the linear measurement of cementum (p < or = 0.05). This study demonstrates successfully the use of the sheep animal model for GTR research, and shows that few differences exist between GTR healing when either GTPM or GTSTP is used in the treatment of class II furcation defects.

In the first part of this article the biological rationale and the use of different implants was considered. In this second part, guided bone regeneration (GTR) around implants, immediate placement of implants, peri-implantitis, and failing implants will be discussed.