title: Self-etching adhesives increase collagenolytic activity in radicular dentin.
abstract: Endogenous matrix metalloproteinases (MMPs) release from crown dentin and their activation results in degradation of hybrid layers created by dentin adhesives. This study tested the hypothesis that instrumented intraradicular dentin possesses latent collagenolytic activity that is activated by mild self-etching adhesives. Root dentin shavings were produced from 50 cleaned and shaped, saline-irrigated root canals using Gates Glidden drills and rinsed with sodium azide to prevent bacterial growth. Dried dentin powder aliquots were treated with two clinically-relevant MMP inhibitors, 2% chlorhexidine for 10 minutes and 17% EDTA for 1 minute. Additional dentin powder was mixed with Clearfil Liner Bond 2V or Clearfil Tri-S Bond for 1 minute followed by extracting the adhesives with acetone. Dentin powder was also treated with 2% chlorhexidine for 10 minutes before or after adhesive application. Collagenolytic activities of the nine groups were assayed with a fluorometer in 96-well plates, by recording the changes in fluorescence before and after addition of fluorescein-labeled type I collagen. Epoxy resin-embedded powders were examined with TEM for the extent of demineralization. Instrumented, mineralized intraradicular dentin possessed low but detectable collagenolytic activity that was inhibited by chlorhexidine (p < 0.001) and EDTA (p < 0.001). Both adhesives partially demineralized the dentin powder and activated latent MMPs, with 14- to 15-fold increases in collagenolytic activities (p < 0.001) that were significantly (p < 0.001) but incompletely inactivated after 10 min application of chlorhexidine. Mild self-etching adhesives activate latent MMPs without denaturing these enzymes, and may adversely affect the longevity of bonded root canal fillings and posts.
authors.affiliation: Department of Oral Biology and Maxillofacial Pathology, Medical College of Georgia, Augusta, GA 30912-1129, USA.
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Loushine
authors.forename: R Norman
authors.initials: RN
authors.lastname: Weller
authors.forename: Francesca
authors.initials: F
authors.lastname: Monticelli
authors.forename: Raquel
authors.initials: R
authors.lastname: Osorio
mesh_terms: D000134:Acid Etching, Dental / Q000009:adverse effects / Q000379:methods; D000269:Adhesives / Q000633:toxicity*; D000704:Analysis of Variance; D002710:Chlorhexidine / Q000494:pharmacology; D024042:Collagen Type I / Q000187:drug effects* / Q000378:metabolism; D001840:Dental Bonding; D003804:Dentin / Q000187:drug effects* / Q000201:enzymology; D017220:Dentin-Bonding Agents / Q000633:toxicity*; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008689:Methacrylates / Q000633:toxicity; D046529:Microscopy, Electron, Transmission; D011480:Protease Inhibitors / Q000494:pharmacology; D019279:Resin Cements / Q000633:toxicity; D012388:Root Canal Irrigants / Q000494:pharmacology; D018709:Statistics, Nonparametric
chemical_list: D000269:Adhesives; C112274:Clearfil Liner Bond 2; C515604:Clearfil Tri-S Bond; D024042:Collagen Type I; D017220:Dentin-Bonding Agents; D061965:Matrix Metalloproteinase Inhibitors; D008689:Methacrylates; D011480:Protease Inhibitors; D019279:Resin Cements; D012388:Root Canal Irrigants; D004492:Edetic Acid; D020782:Matrix Metalloproteinases; D002710:Chlorhexidine