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Background: Transforming growth factor-beta (TGF-beta) represents a family of growth-modulating proteins with fundamental roles in connective tissue and bone development. The objective of this study was to evaluate the potential for regeneration of alveolar bone and cementum following surgical implantation of recombinant human TGF-beta 1 (rhTGF-beta 1)., Method: Bilateral, critical size, supra-alveolar periodontal defects in 5 beagle dogs were surgically implanted with rhTGF-beta 1 in a calcium carbonate carrier (CaCO3) or with carrier alone. The animals were euthanized at 4 weeks postsurgery and block-biopsies of the defects were processed for histologic and histometric analysis., Results: Surgical implantation of rhTGF-beta 1 resulted in minimal, if any, stimulation of alveolar bone or cementum regeneration. Linear bone and cementum regeneration in rhTGF-beta 1-treated defects was 1.2+/-0.6 and 0.01+0.01 mm, respectively. Corresponding values for the controls were 1.0+/-0.6 and 0.01+/-0.03 mm., Conclusions: The results suggest that, under the conditions (dose, carrier, defect type) evaluated here, treatment of periodontal defects in beagle dogs with rhTGF-beta 1 may be of limited clinical benefit.

This study evaluated alveolar bone and cementum regeneration following surgical implantation of recombinant human transforming growth factor-beta1 (rhTGF-beta1) in conjunction with guided tissue regeneration (GTR). Supraalveolar, critical size, periodontal defects were surgically created around the 3rd and 4th mandibular premolar teeth in right and left jaw quadrants in 5 beagle dogs. Alternate jaw quadrants in consecutive animals received rhTGF-beta1, in a CaCO3/hydroxyethyl starch carrier with GTR, or carrier with GTR alone (control). 20 microg of rhTGF-beta1 in buffer solution was incorporated into approximately 0.8 ml of carrier for each defect scheduled to receive rhTGF-beta1. Animals were sacrificed at week 4 postsurgery and tissue blocks were harvested and processed for histometric analysis. Clinical healing was generally uneventful. Minor membrane exposures were observed. Defects with membrane exposure displayed an inflammatory infiltrate underneath the membrane. Bone regeneration of trabecular nature, apparent in all animals, was generally limited to the very apical aspect of the defects. Cementum regeneration was limited without obvious differences between experimental conditions. Comparing rhTGF-beta1, to control defects, statistically significant differences were found for area (1.8+/-0.4 and 1.3+/-0.6 mm2, respectively; p<0.05) and density (0.3+/-0.1 and 0.2+/-0.03, respectively; p<0.05) of alveolar bone regeneration. Observed differences are small and represent a clinically insignificant potential for enhanced regeneration in this preclinical model. Within the limitations of study, it may be concluded that rhTGF-beta1 has a restricted potential to enhance alveolar bone regeneration in conjunction with GTR.

Clinical healing following guided tissue regeneration (GTR) in deep intrabony pockets was compared to healing following gingival flap surgery alone (GFS). 15 patients received the GTR treatment including an expanded polytetrafluoroethylene membrane. 13 other patients received the control treatment GFS. A postsurgery protocol emphasizing wound stability and infection control was used. Treatment effects were evaluated 6 months postsurgery. Mean pre-surgery probing depth for the GTR and control treatments was 7.5 +/- 1.0 and 7.7 +/- 1.5 mm, respectively. Significant probing depth reduction (3.8 +/- 1.2 and 2.9 +/- 1.1 mm), attachment level improvement (2.4 +/- 2.1 and 2.2 +/- 1.2 mm) and bone fill (2.0 +/- 2.0 and 2.4 +/- 0.9 mm) followed the GTR and control protocols, respectively (p < 0.01). Significant differences between GTR and control treatments were observed in probing depth reduction (p < 0.01) and in gingival recession increase (1.7 +/- 1.5 and 0.7 +/- 0.9 mm, respectively; p < 0.05). The results suggest that GTR procedures compared to GFS have similar clinical potential in intrabony pockets, under the present protocol.

Effects of topical citric acid application on tissue maturation was studied in standardized periodontal defects in 6 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and recessed 0.5 mm into the dentin of maxillary canines. 1 defect in each dog was conditioned with a saturated solution of citric acid for 3 min and then rinsed with saline. Control defects in contralateral teeth were treated with saline only for the same length of time. The defects were covered with an expanded polytetrafluoroethylene membrane and the flaps repositioned and sutured. 14 days postsurgery, healing appeared more advanced along the defect walls and floor than in the center of the defect in all instances. Histometrically, citric acid-conditioned defects exhibited a higher density of collagen fibers along the defect walls and floor and adjacent to the barrier membrane as well as more advanced resolution of the residual blood clot than the surgical controls. Differences in fibroblast density within specimen pairs were non-significant. All control defects but none of the acid-conditioned defects showed an artifactual split between the dentin walls and the granulation tissue. This study failed to support the contention that topical application of citric acid to root surfaces may delay healing following periodontal surgery.

This study evaluated intra- and inter-examiner reproducibility for a conventional manual probe versus a computer-interfaced force-controlled periodontal probe. 2 examiners recorded probing depths (PD) and relative attachment levels (AL) at 1128 sites in 15 periodontal maintenance patients. Each site was evaluated 2x, 7 to 10 days apart by both examiners. Probing force for the electronic probe was 15 g. PD intra-examiner reproducibility (within +/- 1.0 mm) for shallow sites (PD < or = 3 mm) was 98.6% versus 91.5% for the conventional versus the electronic probe for examiner 1 and 98.5% versus 88.7% for examiner 2. Corresponding values for deeper sites (PD > 3 mm) were 96.4% versus 85.9% for examiner 1 and 95.1% versus 77.0% for examiner 2. Generally, AL intra-examiner reproducibility was 1 to 3% lower than for PD. PD inter-examiner reproducibility (within +/- 1.0 mm) was 99.2% versus 90.7% for the conventional versus the electronic probe, respectively, for shallow sites and 95.4% versus 76.9% for deeper sites. AL inter-examiner reproducibility (within +/- 1.0 mm) was 1 to 5% lower than for PD. Both intra- and inter-examiner reproducibility was higher for anterior than for posterior sites. Mean PD and AL were similar for both examiners. However, the electronic probe consistently recorded 0.1 to 0.2 mm higher values than the conventional probe. Standard deviations indicated a greater variability for electronic than for manual probing. The results suggest that intra- and inter-examiner reproducibility may not necessarily be higher with an electronic, force-controlled periodontal probe than with a conventional manual probe.