Results: SRP+HBOT resulted in greater probing reduction and attachment gain than SRP alone 3 months after treatment (p<0.001). The BANA test was negative after 1 week only for sites in the SRP+HBOT group (p<0.05). However SRP+HBOT failed to show a significant difference from SRP group after 3 months were all BANA sites became negative (p>0.05).