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Background: Bisphosphonates (BPs) and low-dose doxycycline (LDD) have been shown to inhibit bone resorption and to improve the levels of proinflammatory mediators and destructive enzymes in gingival tissues, respectively. The purpose of this study is to evaluate the effect of mono and combined BP clodronate and LDD therapies in reducing gingival levels of matrix metalloproteinase-9 (MMP-9), interleukin-1β (IL-1β), and alveolar bone loss in rats with diabetes.Methods: Fifty adult Wistar rats were divided into five study groups as follows: 1) group 1 = diabetes control; 2) group 2 = diabetes + periodontitis; 3) group 3 = diabetes + periodontitis + LDD; 4) group 4 = diabetes + periodontitis + clodronate; and 5) group 5 = diabetes + periodontitis + LDD + clodronate. LDD and clodronate were given as a single agent or as combination therapy during the 7 days of the post-experimental periodontitis period. On day 7, the rats were sacrificed, the mobility of the tooth was recorded, and block biopsies were removed. The gingival tissues were analyzed histologically and immunohistochemically for expression of MMP-9 and IL-1β. Alveolar bone loss was evaluated morphometrically under a light microscope. Data analysis was performed statistically by Kruskal-Wallis and post hoc Tukey and Spearman correlation tests.Results: Alveolar bone loss was significantly greater in groups 2 through 5 than group 1 (P <0.05) but was not significantly different among groups 2 through 5 (P >0.05). Animals with periodontitis (group 2) expressed significantly higher levels of MMP-9 and IL-1β compared with those without periodontitis (group 1) (P <0.05). MMP-9 expression was significantly lower in group 3 than groups 1, 2, and 5 (P <0.05). IL-1β expression was significantly lower in the groups 1, 3, 4, and 5 than 2 (P <0.01) but was not significantly different among groups 1, 3, 4, and 5. Positive correlations were found between alveolar bone loss and density of inflammation (ρ = 0.319, P = 0.021) and between MMP-9 and IL-1β (ρ = 0.418, P = 0.002), respectively.Conclusion: Our findings suggest that ligature-induced periodontitis in animals with diabetes results in significantly higher levels of MMP-9 and IL-1β expression in gingiva. The use of mono and combined clodronate and LDD administrations may significantly reduce levels of MMP-9 and IL-1β expression. However, drug administration did not affect alveolar bone levels during the study period. [ABSTRACT FROM AUTHOR]

Background: The essential amino acid taurine has important physiologic and pathologic roles, and has been shown to have osmoregulatory, antioxidative, antiapoptotic, anti-inflammatory, and antilipid activities. However, the response of oral gingival epithelium to taurine during wound healing remains unclear. The goal of this study is to evaluate the expression of laminin 5 and Type IV collagen histologically in regenerating gingival epithelium after direct application of taurine on incised human gingival samples. Methods: The study was conducted on 16 gingival samples obtained from gingivectomy specimens of eight adult patients with generalized gingival overgrowth. The samples were divided into two groups: gingival with 1% taurine-hydrated collagen membrane (n = 8) and saline-hydrated collagen membrane (n = 8) applied specimens. The length of the newly formed epithelium on the wound surface and inflammation was assessed on hematoxylin and eosin-stained sections. Basement membrane formation was evaluated by detection of laminin 5 and Type IV collagen expressions on immunohistochemically stained samples. Results: Complete new epithelial formation was observed in 1% taurine-treated gingivectomy specimens, whereas incomplete regeneration of the epithelium was observed in control gin- givectomy specimens (P<0.05). The length of the newly formed epithelium showed a negative correlation with inflammation in the taurine group (P=-0.712; P<0.05). lmmunoreactivity for both laminin 5 and Type IV collagen did not show any significant difference between groups. Conclusion: The local application of taurine-hydrated collagen membrane on human gingival wounds demonstrated the histologic evidence of rapid reepithelization with taurine. [ABSTRACT FROM AUTHOR]

Background: Smoking causes an increase in the thickness of gingival epithelium, which is the outcome of increased keratinocyte proliferation or loss. Smoking related changes in the proliferative activity of the gingival epithelium are largely uncharacterized for periodontal diseases. The aim of the present study was to determine the effects of smoking on the proliferation of the epithelium in periodontally diseased marginal gingiva by comparing the expression patterns of two different proliferation markers. Methods: Gingival biopsies (N = 60) were obtained from smokers who had clinically healthy gingiva (n = 10), smokers with gingivitis (n = 10), smokers with periodontitis (n = 10), non-smokers with clinically healthy gingiva (n = 10), nonsmokers with gingivitis (n = 10), and non-smokers with periodontitis (n = 10). The quantitative measurement of maximum epithelial thickness was performed on hematoxylin and eosinstained sections. The expression patterns for proliferating cell nuclear antigen (PCNA) and Ki67 were evaluated immunohistochemically. Results: The percentage of PCNA-positive cells was higher than the percentage of Ki67-positive cells in all groups (P <0.001). When the mean values of PCNA and Ki67 were compared in each group, a statistically significant difference was observed only in the healthy smoker group (P = 0.003). Significant differences in PCNA proliferation indices were only found between the smoker group and the non-smoker healthy group (P = 0.015). Conclusions: Smoking had an affect on the proliferation of cells in the oral gingival epithelium, regardless of periodontal status. The increase in thickness of the epithelium was not associated with smoking; periodontal status and inflammation seemed to be more important factors. Smoking induced the replication activity of gingival epithelium and induced DNA repair. [ABSTRACT FROM AUTHOR]

Fractures of the maxillofacial region are common in the elderly people. Titanium and LactoSorb screws are the widely accepted materials for use in the maxillofacial fractures. This study was undertaken to evaluate the early tissue response following the insertion of both titanium and LactoSorb screws composed of 82% PLLA and 18% PGA in an elderly animal model. In this study, 22 titanium and 22 LactoSorb screws were applied to calvaria of 44 guinea pigs that were 10-11 months old. Animals were sacrificed on postoperative days 3, 7, 14, 30 and 60. Screws were retrieved with surrounding bone tissue and the specimens were prepared for routine histologic examination. All the specimens were evaluated by light microscopy. Histometric analysis revealed that there was no significant difference between LactoSorb and titanium screws for the new bone formation. The biodegradation of LactoSorb screws was not complete by the end of day 60. In conclusion, both materials were well tolerated and induced bone formation without causing adverse tissue response in an elderly animal model. Our results suggest that both LactoSorb and titanium miniplates and screws can be used safely, regardless of the increasing age. However, LactoSorb may be the first choice as it does not require a second operation for removal and has late biodegradation in elderly that keeps its support for a relatively longer time during fracture healing. [ABSTRACT FROM AUTHOR]