Effects of 1% Hyaluronan Gel on Critical Size Defects-Radiographic Evaluation

Objective: Hyaluronan is an important component of extracellular matrix and plays a key role in wound healing. Besides its important role in wound healing it also possesses other functions such as homeostasis and bone healing. The objective of this study was to conduct a radiographic evaluation on the effects of 1% hyaluronan in bone healing using a critical size rat-calvaria defect model. Methods: Thirty adult male Wistar rats were used in this study. Two 6 mm critical-size defects were created in 24 animals and the treatments were randomly distributed, the other six animals were used as positive controls for radiographic analysis. Four treatments were evaluated: 1) 1% hyaluronan gel; 2) 1% hyaluronan soak-loaded onto an absorbable collagen sponge(ACS) carrier; 3) saline; and 4) ACS alone. The animals were sacrificed at 4 and 8 weeks when biopsies were collected and radiographs were obtained using a direct digital radiograph system (Sens-A-Ray 2000) and a standardized protocol. A blind examiner evaluated the radiographic density of the images twice and an intraclass correlation was performed (R2=0.99, p<0.001). Student t test was used for intragroup comparisons, and one-way ANOVA and Tukey's tests were used for intergroup comparisons, and a 5% significance level was established. Results: There were no noteworthy differences between 4 or 8 weeks within each treatment group (p>0.05). When treatments were compared no significant differences between groups were found (p>0.05), treatment 2, however, had the highest density of all groups (51.75±13.56 – 4 weeks, and 50.32±8.65 – 8 weeks). Conclusion: Within the limits of this study it can be concluded that 1% hyaluronan gel alone or its association with a carrier(ACS) do not improve bone healing.