*4.8. Statistical Analysis*

The results were analyzed by the software SPSS 21 (SPSS, Inc., Chicago, IL, USA). Sample size estimation was performed considering a statistical power of 0.8 and alpha error of 0.05. Mean values of healing rates, thickness of the skin and collagen type I and III expression were compared between groups using Mann-Whitney's U test. Differences with *p*-value < 0.05 were considered statistically significant.
