RESULTS	MTBS values for groups BP ( 21.3 MPa ) , SBP ( 31MPa ) , MDPP ( 30.1 MPa ) and SBMDPP ( 32.3 MPa ) were significantly higher in specimens treated with NTP than their untreated counterparts B ( 9.1 MPa ) , SB ( 14.4 MPa ) , MDP ( 17.8 MPa ) and SBMDP ( 24.1 MPa ) .\