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Background:The purpose of this study was to evaluate if the healing of full‐thickness skin wounds was accelerated by platelet‐rich plasma (PRP). Methods:Four 2.5 × 2.5‐cm full‐thickness skin wounds were created on the backs of 15 New Zealand white rabbits. One wound on each animal received 0.3, 0.6, or 0.9 ml PRP, and the fourth wound served as a control. Seven and eight animals were sacrificed after 1 or 2 weeks, respectively, to determine histomorphometrically the epithelialization rate, contraction rate, healing rate, tissue fill, and volume fractions of fibroblasts, neutrophils, macrophages, and blood vessels. Results:Only the 0.6‐ and 0.9‐ml groups had significantly lower contraction rates than the controls after 2 weeks (P<0.05). Although no statistically significant differences were found in other parameters between the PRP‐treated wounds and the controls, the PRP treatment led to increases in average epithelialization rates and volume fraction of blood vessels at both time periods. The PRP also seemed to have the most positive effect on healing rate, tissue fill, and volume fraction of fibroblasts during week 1 compared to week 2. Conclusions:The PRP treatment enhanced healing in full‐thickness wounds by reducing the contraction rate with a trend toward acceleration of the epithelial migration and the angiogenic response. Further studies with larger sample sizes should be conducted to improve statistical sensitivity. Longer time intervals and modifications of PRP volume should also be explored to evaluate the long‐term efficacy of PRP on wound healing.

Background:Periodontal regeneration success may be limited by placing bone grafts and membranes in infected sites. The objective of this study was to test the hypothesis that adjunctive subgingival administration of chlorhexidine gelatin bioresorbable chips enhances bone gain when used in conjunction with guided tissue regeneration. Methods:This was a single center, blinded, 2‐arm parallel design study of 44 subjects with one or more sites with probing depth and clinical attachment loss ≥5 mm following initial therapy and radiographic evidence of bone loss. The patients were randomly assigned to receive either chlorhexidine (CHX) chip or sham chip placement one week prior to regenerative therapy that included graft placement and site coverage with guided tissue membranes. Patients also received CHX or sham chip placement, per their randomization, adjunctively to scaling and root planing or maintenance procedures. Periodontal examinations were completed at baseline (8 weeks prior to surgery); 1 week prior to surgery; and at 3, 6, and 9 months postsurgery. The major outcomes for the study were changes in bone height and bone mass as measured from standardized radiographs used for quantitative digital subtraction radiography over the 11‐month study period. Results:Subjects receiving sham chip placement gained a mean bone height of 1.49 ± 0.22 mm, while patients receiving the CHX chips gained significantly more bone height (3.54 ± 0.45 mm; P<0.001). Similarly, subjects receiving CHX chips as an adjunct gained significantly more bone mass (5.57 ± 0.69 mg; P <0.001) than the standard therapy (2.59 ± 0.34 mg). Conclusions:These pilot results indicate that locally delivered, controlled‐release antimicrobial treatment may improve the amount of bone gain during guided tissue regeneration procedures. These data support the evidence that infection control is an important variable in successful regeneration. J Periodontol 2003;74:411‐419.

Background:Previous multi‐center trials demonstrated the efficacy of a biodegradable chlorhexidine‐gelatin chip (CHX) in reducing probing depth in patients with periodontitis. The present study utilized a subset of subjects from the parent study to determine if the CHX chip was effective in maintaining alveolar bone over a 9‐month period. Methods:Forty‐five subjects with at least four 5 to 8 mm pockets, stratified by smoking status, were enrolled in this double‐blind controlled, placebo‐controlled trial. Control groups received either placebo chip plus scaling and root planing (SRP) or SRP alone. Test group subjects received active CHX chip or SRP alone (to maintain the blind). Standardized radiographs were taken for quantitative digital subtraction radiography at baseline and 9 months. Results:At 9 months, 15% of SRP treated subjects experienced loss of bone in 1 or more sites, no subject treated with active chip plus SRP lost bone (P<0.01). At 9 months, significant differences in the change in probing depth and clinical attachment levels favoring the active chip over SRP alone or SRP plus CHX chip were also observed (P<0.05). Conclusions:These data indicate that the CHX chip, when used as an adjunct to scaling and root planing, significantly reduces loss of alveolar bone. J Periodontol 2000;71:256‐262.

A nineteen year old white femalewas referred for an evaluation of severe, rapidly progressive periodontitis. Although the patient was physically healthy and did not demonstrate any remarkable abnormalities in routine laboratory tests or upon physical examination, a detailed immune profile elucidated abnormal findings. Additionally, the patient demonstrated a poor healing response after tooth removal and a continued loss of bone following insertion of dentures.

The present studies evaluatedthe efficacy of a controlled‐release biodegradable Chlorhexidine (CHX) (2.5 mg) chip when used as an adjunct to scaling and root planing on reducing probing depth (PD) and improving clinical attachment level (CAL) in adult periodontitis. Two double‐blind, randomized, placebo‐controlled multicenter clinical trials (5 centers each) were conducted; pooled data are reported from all 10 centers (447 patients). At baseline, following 1 hour of scaling and root planing (SRP) in patients free of supragingival calculus, the chip was placed in target sites with PD 5 to 8 mm which bled on probing. Chip placement was repeated at 3 and/or 6 months if PD remained ≥ 5 mm. Study sites in active chip subjects received either CHX chip plus SRP or SRP alone (to maintain study blind). Sites in placebo chip subjects received either placebo chip plus SRP or SRP alone. Examinations were performed at baseline; 7 days; 6 weeks; and 3, 6, and 9 months. At 9 months significant reductions from baseline favoring the Chlorhexidine chip compared with both control treatments were observed with respect to PD (Chlorhexidine chip plus SRP, 0.95 ± 0.05 mm; SRP alone, 0.65 ± 0.05 mm, P< 0.001; placebo chip plus SRP, 0.69 ± 0.05 mm, P< 0.001) and CAL (Chlorhexidine chip plus SRP, 0.75 ± 0.06 mm; SRP alone, 0.58 ± 0.06 mm, P< 0.05; placebo chip plus SRP, 0.55 ± 0.06 mm, P< 0.05). The proportion of patients who evidenced a PD reduction from baseline of 2 mm or more at 9 months was significantly greater in the Chlorhexidine chip group (19%) compared with SRP controls (8%) (P< 0.05). Adverse effects were minor and transient toothache, including pain, tenderness, aching, throbbing, soreness, discomfort, or sensitivity was the only adverse effect that was higher in the Chlorhexidine group as compared to placebo (P= 0.042). These data demonstrate that the adjunctive use of the Chlorhexidine chip results in a significant reduction of PD when compared with both SRP alone or the adjunctive use of a placebo chip. These multi‐center randomized control trials suggest that the Chlorhexidine chip is a safe and effective adjunctive chemotherapy for the treatment of adult periodontitis. J Periodontol 1998;69:989–997.

This study sought to evaluatethe ability of gingival crevicular fluid (GCF) elastase to predict attachment and bone loss in human Periodontitis. Thirty subjects who were medically healthy and had a history of progressive Periodontitis were studied with an automated probe. Five sites in each patient were monitored bi‐monthly for a 6‐month period for attachment loss. Subtraction radiography was utilized at the beginning and end of the study to monitor bone loss. GCF elastase was measured at 0 month and then bi‐monthly by collecting GCF on paper strips impregnated with PMN leukocyte elastase substrate inserted into the gingival crevice for 15 seconds. After 8 minutes of reaction time, the strips were scored relative to fluorescent standards in an ultraviolet view box. Strips were then eluted in methanol and total elastase measured by spectrofluorometry. Total elastase was significantly higher in sites demonstrating progressive attachment loss than in inactive sites (2.81 ±.29 verus 2.03 ±.07, P < 0.0005) and sites demonstrating bone loss (2.32 ±.17 versus 2.01 ±.08 P < 0.05). When considering the joint presence of bone loss and attachment loss of 1.0 mm or greater in the 6‐month period following a visual elastase kit score of 2 or greater, the test kit shows a sensitivity and specificity of 82% and 66%, respectively. This study demonstrated that GCF elastase levels are significantly higher in sites demonstrating progressive periodontal attachment and bone loss assessed 6 months later and may serve as a predictor of future bone and attachment loss. J. Periodontol 1992; 63:237–242.