The effect of hyaluronan on bone and soft tissue and immune response in wound healing

Background: The aims of this study were to investigate the anti-inflammator y effect and the effect on bone regeneration of hyaluronan in surgical and non-surgical groups. Methods: In each of 15 individuals, 2 teeth with defects of similar charact er and magnitude in the upper or lower jaw were chosen. There were at least 2 teeth between the test and the control sites. In the surgical group, a b ioabsorbable membrane was used for both test and control sites, and hyaluro nan was placed in the intrabony pocket of the test site. In the non-surgica l group, the periodontal pockets were scaled and hyaluronan was administere d 3 times with an interval of 1 week in the test pockets. Alveolar bone hei ght and bone healing patterns were analyzed using digital intraoral radiogr aphs. Measurements of bone height were performed in the original digital bl ack-and-white radiographs to obtain quantitative data on bone gain or loss. Bone healing patterns were studied with color-coded radiographs, using spe cially designed software in a personal computer with subsequent combination s of radiographs. Gingival crevicular fluid immunoglobulin (1g)G, C3, and p rostaglandin E-2 (PGE(2)) responses; periodontal probing depth; bleeding on probing; and the presence of plaque were studied to evaluate the anti-infl ammatory effect. Data were obtained at baseline before treatment, and at 2 weeks, and 1, 3, 6, and 12 months after treatment. Results: For the surgical treatments, bone height was increased in the test group treated with hyaluronan (mean value 2.2%, corresponding to an averag e increase of approximately 0.5 mm) and reduced in the control group (mean value -1.8%, corresponding to an average decrease of approximately -0.4 mm) (P <0.05) after 12 months. For the non-surgical treatments, bone height wa s reduced by a mean value of -1.1% (corresponding to an average decrease of approximately -0.25 mm) in the test group treated with hyaluronan and -3.3 % (corresponding to an average decrease of approximately -0.75 mm) in the c ontrol group after 12 months (ICS.). According to the digital color-coded r adiographs, the test sites in the surgical and non-surgical groups showed a pposition of bone minerals. Immune responses showed no differences during t he 12 months studied for the surgical and non-surgical sites. Mean periodon tal probing depths were reduced between 2.5 mm and 4.1 mm in the surgical a nd non-surgical groups. Conclusions: The observed difference in bone height between test and contro l sites in the surgical group after 12 months was less than 1 mm, which was only detectable on radiographs. No statistical difference was found on rad iographs in the non-surgical group, where a decrease in bone height was fou nd for both groups after scaling. Probing depth reduction after the surgica l treatment, as well as after scaling and root planing, was as expected. Hy aluronan in contact with bone and soft tissues had no influence on the immu ne system in this study. Further studies are needed to determine the extent to which hyaluronan can lead to clinically significant healing of periodon tal lesions.