151 Effects of acid-etching on endogenous MMP activity of EDTA-demineralized dentin

Thursday, March 22, 2012: 10:45 a.m. - 12:15 p.m.
Presentation Type: Oral Session
A. TEZVERGIL-MUTLUAY1, M. MUTLUAY1, R. SESEOGULLARI-DIRIHAN1, K. AGEE2, L. BRESCHI3, A. MAZZONI4, L. TJADERHANE5, Y. NISHITANI6, F. TAY2, and D. PASHLEY2, 1University of Turku, Turku, Finland, 2College of Dental Medicine, Georgia Health Sciences University, Augusta, GA, 3Department of Biomedicine, University of Trieste, Trieste, Italy, 4University of Bologna, Bologna, Italy, 5Institute of Dentistry, University of Oulu, Oulu, Finland, 6Okayama University, Kurashiki-shi, Japan

Objectives:   Previous studies suggest that acid-etching dentin with 37% phosphoric acid (PA) inactivates MMPs by denaturing them.  Some think that the MMPs are temporarily covered by CaHPO4-reaction products that mask the MMPs.  The purpose of this work was to completely demineralize dentin beams with 0.5 M EDTA pH 7.4, and then “acid-etch” the matrix with increasing concentrations of PA to see if they can decrease dentin MMP activity.  Methods:   Control beams (n=10) were incubated in a simulated body fluid (SBF, 1 mL); experimental beams were incubated in 2 mM APMA 1 hr; PA experimental beams were dipped in 1, 10 or 37% PA for 15 min or 37% PA for 15 sec, rinsed and then incubated in 1 mL of SBF for 1 day or 1 week.  Aliquots of the SBF were analyzed for C-terminal telopeptides (ICTP) using an ELISA kit.  Results:   in ng/mg dentin are:



Phosphoric acid 15 min

PA 15 sec


Control SBF






1 day







1 wk







Conclusions:   These results clearly show that 1, 10 and 37 mass % PA do not lower endogenous MMP activity in dentin matrices that are free of buffer.  Instead, 10-37% PA increases endogenous MMP activity of dentin matrices demineralized in EDTA above that produced by APMA at 1 day, suggesting that acids activate these MMPs better than the traditional APMA activator.  Supported, in part, by R01DE015306 from the NIH/NIDCR to DHP (PI) and by grant #8126472 from the Academy of Finland to AT-M (PI).

This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR R01DE015306

Keywords: Acid etch, Collagen, Dentin, Dentin bonding agents and MMPs
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