title: Collagen degradation in endodontically treated teeth after clinical function.
abstract: Endodontically treated teeth restored with posts are susceptible to coronal leakage after long-term function. We hypothesize that demineralized collagen matrices (DCMs) created in dentin by acidic zinc phosphate cement within the dowel spaces degrade with time. Forty-two post-restored teeth were extracted after three periods of clinical service and were examined, by means of scanning and transmission electron microscopy, for the status of the DCMs. SEM revealed a progressive degradation of the DCMs, becoming less dense after 3 to 5 years, losing structural integrity after 6 to 9 years, and partially disappearing after 10 to 12 years. TEM revealed evidence of collagenolytic activity within the DCMs, with loss of cross-banding and unraveling into microfibrils, and gelatinolytic activity that resulted in disintegration of the microfibrils. Bacterial colonization and the release of bacterial enzymes and of host-derived matrix metalloproteinases may contribute to the degradation of collagen fibrils in root dentin after clinical function.
authors.affiliation: Dental Materials and Restorative Dentistry Department, University of Siena, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Ferrari
authors.forename: P N
authors.initials: PN
authors.lastname: Mason
authors.forename: C
authors.initials: C
authors.lastname: Goracci
authors.forename: D H
authors.initials: DH
authors.lastname: Pashley
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D001419:Bacteria / Q000201:enzymology; D003094:Collagen / Q000378:metabolism* / Q000648:ultrastructure; D017364:Collagenases / Q000378:metabolism; D003804:Dentin / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D005500:Follow-Up Studies; D018093:Gelatinases / Q000378:metabolism; D006801:Humans; D020894:Microfibrils / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D012189:Retrospective Studies; D012390:Root Canal Therapy; D013997:Time Factors; D019553:Tooth, Nonvital / Q000378:metabolism* / Q000382:microbiology / Q000628:therapy; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D015036:Zinc Phosphate Cement; D003094:Collagen; D017364:Collagenases; D018093:Gelatinases