Effects of granule size on the osteoconductivity of bovine and synthetic hydroxyapatite: a histologic and histometric study in dogs.

Two bovine hydroxyapatites (BHAs), one with granule size of 150 to 200 microm and one with granule size of 300 to 329 micro, and 2 synthetic hydroxyapatites (SHAs), with granule size of 150 and 300 microm, respectively, were compared for effectiveness in repairing circumferential bone defects in dogs. The hydroxyapatites (HAs) were characterized through powder x-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Three trephined bone defects (5.0 mm wide x 4 mm long) were created in the humeruses of 8 dogs. In a random manner, the defects on each side were treated with either BHA with small granules (BHA[s]), BHA with large granules (BHA[L]), SHA with small granules (SHA[s]), SHA with large granules (SHA[L]), or left to heal unaided (bilateral control). Four dogs were sacrificed after 6 and 12 postoperative weeks, respectively. Ground sections of each defect were submitted to histologic and histomorphometric analysis (percentage of area occupied by bone, bone marrow, and biomaterial). As a rule, the HA granules exhibited direct bone contact, regardless of the origin and the size of the granules. Control sites were related and had an increased amount of connective tissue infiltration. At 12 weeks, BHA(s) exhibited improved bone formation compared with SHA(s) and SHA(L). The SHA(s) delivered reduced amounts of bone compared with the remaining groups (control included). The area of bone measured in BHA(s) sites was significantly higher at 12 weeks than 6 weeks. The XRD revealed the tested HA samples to be highly crystalline, while BHA appeared with rougher surface at SEM analysis. The BHA(s) performed better than the SHA(s) and SHA(L), as assessed by the amount of bone measured in both implantation sites at 12 weeks. The BHA's material characteristic itself rather than granules size accounted for the distinctive biological behavior. The increased roughness of the BHAs' surface, as assessed through SEM, seemed to benefit the osteoconduction process.

A 6-month comparative clinical study of a conventional and a new surgical approach for root coverage with acellular dermal matrix.

BACKGROUND: The acellular dermal matrix graft (ADMG) has become widely used in periodontal surgeries as a substitute for the subepithelial connective tissue graft (SCTG). These grafts exhibit different healing processes due to their distinct cellular and vascular structures. Therefore the surgical technique primarily developed for the autograft may not be adequate for the allograft. This study compared the clinical results of two surgical techniques--the "conventional" and a modified procedure--for the treatment of localized gingival recessions with the ADMG. METHODS: A total of 32 bilateral Miller Class I or II gingival recessions were selected and randomly assigned to test and control groups. The control group received the SCTG and the test group the modified surgical technique. Probing depth (PD), relative clinical attachment level (RCAL), gingival recession (GR), and width of keratinized tissue (KT) were measured 2 weeks prior to surgery and 6 months post-surgery. RESULTS: Both procedures improved all the evaluated parameters after 6 months. Comparisons between the groups by Mann-Whitney rank sum test revealed no statistically significant differences in terms of CAL gain, PD reduction, and increase in KT from baseline to 6-month evaluation. However, there was a statistically significant greater reduction of GR favoring the modified technique (P = 0.002). The percentage of root coverage was 79% for the test group and 63.9% for the control group. CONCLUSION: We conclude that the modified technique is more suitable for root coverage procedures with the ADMG since it had statistically significant better clinical results compared to the traditional technique.

Effect of non-surgical periodontal therapy on glycemic control in patients with type 2 diabetes mellitus.

BACKGROUND: The literature suggests that an alteration in glucose metabolism occurs as a result of antibacterial periodontal therapy. The objective of this study was to monitor the effect of non-surgical periodontal therapy on glycemic control in patients with type 2 diabetes mellitus (DM). METHODS: Thirty type 2 DM subjects with periodontitis were randomly divided into two groups. Group 1 (G1), 15 subjects, received one-stage full-mouth scaling and root planing (FMSRP) plus amoxicillin/clavulanic acid 875 mg; group 2 (G2), 15 patients, received only FMSRP. At baseline and after 3 months, the glycated hemoglobin (HbA1c) values, fasting glucose, and clinical parameters (with computerized probing and individualized acrylic stents) were recorded. Following therapy, the subjects were enrolled in a 2-week interval maintenance program for 3 months. RESULTS: After treatment, both groups showed clinical improvements. A probing depth (PD) reduction of 0.8 +/- 0.6 mm (P < 0.05) occurred in G1 and 0.9 +/- 0.4 mm in G2 (P < 0.05), but there were no significant changes in attachment level. Treatment reduced the HbA1c values after the 3-month observation period in both groups; however, the reduction in HbA1c values for the G2 group was statistically significant, but not for the G1 group. The changes in fasting glucose levels were not significant for either group. CONCLUSIONS: Periodontal therapy improved glycemic control in patients with type 2 DM in both groups; however, the reduction in HbA1c values reached statistical significance only in the group receiving scaling and root planing alone [correction].