Intra- and inter-examiner reproducibility in keratinized tissue width assessment with 3 methods for mucogingival junction determination.

BACKGROUND: Although the need for "adequate" amount of keratinized tissue (KT) for periodontal health is questionable, the mucogingival junction (MGJ) often serves as a measurement landmark in periodontal evaluations. Limited information is available on the reproducibility of KT width (KTW) assessment. The purpose of this study was to assess intra- and inter-examiner reproducibility in measuring KTW by using 3 different methods to identify MGJ location. METHODS: Fifteen patients provided 17 teeth which had undergone a gingival augmentation procedure (connective tissue graft; surgery group) and an equal number of contralateral, non-treated teeth (control group). At the midbuccal aspect of each tooth, KTW was assessed by 2 independent examiners after MGJ identification by the visual (VM), functional (FM), and visual with histochemical staining (HM) method. Data analysis was based on intra-class correlation coefficients (ICC) and 3-way analysis of variance (ANOVA) for differences between replicate measurements. RESULTS: KTW was significantly different between treated and control teeth. No significant differences in KTW were found in relation to method for MGJ determination and examiner. Intra- and inter-examiner reproducibility was high, regardless of treatment status or method for MGJ determination (ICC = 0.92 - 0.99). Standard deviations of the difference between replicate measurements ranged from 0.46 mm for VM to 0.21 mm for HM. CONCLUSIONS: Intra- and inter-examiner reproducibility has been shown to be substantially consistent when different methods for MGJ determination are used to measure the apico-coronal dimension of the gingiva. The level of reproducibility does not seem to be affected whether or not the mucogingival complex has been surgically altered by a gingival augmentation procedure.

HLA-B27 transgenic rats are susceptible to accelerated alveolar bone loss.

BACKGROUND: HLA-B27 transgenic rats exhibit generalized, severe inflammatory reactions and spontaneously develop arthritis and chronic gastrointestinal inflammation, as well as inflammatory lesions in other tissues. Our hypothesis was that HLA-B27 rats would also be susceptible to inflammatory periodontal disease, and therefore alveolar bone loss. The purpose of this investigation was to compare the naturally occurring alveolar bone loss in HLA-B27 and wild type rats. METHODS: Age- and sex-matched HLA-B27 transgenic (TG) and wild type Fischer 344 (WT) female retired breeders, and their age-matched male WT breeding mates, were examined for alveolar bone loss (ABL). Thirty-eight animals were used: twelve, 20, and 6 animals were 6, 8, and 12 months old, respectively. ABL was measured as the exposed root surface area (mm2) in the defleshed maxilla and mandible. RESULTS: The coefficient of variation for replicate ABL measurements was 4.4%. For the 6- and 8-month age groups, ABL was significantly greater in TG rats compared to WT rats. The observed difference in ABL between TG and WT animals did not reach statistical significance for the 12-month age group. Within each of the two animal groups (TG and WT), ABL was significantly different between age groups. The ABL rate of TG female rats was 42% to 250% greater than that of WT female rats, depending on the age range examined. CONCLUSIONS: HLA-B27 rats are susceptible to accelerated alveolar bone loss and could serve as an animal model of alveolar bone loss pathogenesis.

Periodontal repair in dogs: histologic observations of guided tissue regeneration with a prostaglandin E1 analog/methacrylate composite.

This report describes observations of healing following guided tissue regeneration (GTR) including surgical implantation of the prostaglandin E1 analog misoprostol with calcium-layered methacrylate particles. Critical size, supra-alveolar periodontal defects were surgically created around the 3rd and 4th mandibular premolar teeth in 4 beagle dogs. Wound management included soaking with a 24 microg/ml misoprostol solution and implantation of the misoprostol/methacrylate composite. One jaw quadrant per animal was prepared for GTR using expanded polytetrafluoroethylene membranes. The gingival flaps were coronally advanced and sutured to submerge the teeth. The tissues covering the surgical sites daily received topical misoprostol in an oral adhesive over the 4-week healing interval. Upon euthanasia, tissue blocks were prepared for histometric analysis of regeneration of alveolar bone and cementum, root resorption and ankylosis. The defect area underneath the membrane and the density of methacrylate particles were recorded for the GTR defects. The methacrylate particles appeared encapsulated in a dense connective tissue without signs of an inflammatory reaction, some in contact to newly formed bone. Alveolar bone regeneration height averaged (+/-SD) 1.2+/-1.0 and 1.0+/-0.6 mm for GTR and non-GTR defects, respectively. Corresponding values for bone regeneration area were 1.3+/-1.0 and 0.7+/-0.5 mm2. Cementum regeneration was confined to the apical aspect of the defects. Small areas of root resorption and ankylosis were observed for all teeth. Bone regeneration area correlated positively to the defect area and negatively to the density of methacrylate particles in the GTR defects. The histologic observations suggest that the methacrylate composite has marginal potential to promote bone and cementum regeneration under provisions for GTR.

Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment.

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of alveolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surgically produced and immediately implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier in 8, young adult, male, beagle dogs. 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/defect approximately 4.0 mL) in contralateral defects following an incomplete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.10 mg/mL) in contralateral defects (controls). The animals were euthanised at 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects receiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar regeneration comprising 86%, 96%, and 88% of the defect height, respectively. Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, respectively. Root resorption was observed for all rhBMP-2 concentrations. Ankylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and cementum regeneration, root resorption, or ankylosis. Within the selected rhBMP-2 concentration and observation interval, there appear to be no meaningful differences in regeneration of alveolar bone and cementum. There also appear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with rhBMP-2 concentration.