title: Resorbable collagen membranes: histopathologic features.
abstract: OBJECTIVE
  Resorbable collagen membranes (RCMs) are commonly used by oral surgeons, periodontists, and endodontists for multiple purposes. We report 6 cases of RCMs that did not resorb as expected and describe the histopathologic features.
  
  
  METHODS
  Cases of an unusual fibrillar foreign material were noted in biopsy specimens curetted from bone. Hematoxylin-eosin and Masson trichrome stains were performed. Clinicians were contacted for detailed clinical information.
  
  
  RESULTS
  There were 3 men and 3 women. RCMs presented as hyalinized, paucicellular, delicate eosinophilic fibrils or a meshwork without a foreign body reaction. They were refractile and stained for Masson trichrome as expected. These RCMs persisted longer than expected (2-6 weeks) in 3 cases and may have retarded healing in 5 cases.
  
  
  CONCLUSIONS
  Although RCM is supposed to be fairly rapidly resorbable, this material sometimes persists within wound sites without any obvious foreign body reaction and may retard healing.
authors.affiliation: Graduate student, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA. Electronic address: soulafa_almazrooa@hsdm.harvard.edu.
authors.forename: Soulafa A
authors.initials: SA
authors.lastname: Almazrooa
authors.affiliation: Associate Professor, Boston University Henry Goldman School of Dental Medicine, Boston, MA, USA; Associate Pathologist, StrataDx Inc, Cambridge, MA, USA.
authors.forename: Vikki
authors.initials: V
authors.lastname: Noonan
authors.affiliation: Associate Professor, Department of Oral Medicine and Oral Pathology, Harvard School of Dental Medicine, Boston, MA, USA; Associate Surgeon, Division of Oral Medicine and Dentistry, Brigham and Women's Hospital, Boston, MA, USA; Co-director, Oral Pathology Center, StrataDx Inc, Cambridge, MA, USA.
authors.forename: Sook-Bin
authors.initials: SB
authors.lastname: Woo
mesh_terms: D020341:Absorbable Implants; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003094:Collagen; D005260:Female; D005549:Foreign-Body Reaction / Q000473:pathology*; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D009059:Mouth Diseases / Q000601:surgery*
chemical_list: D008567:Membranes, Artificial; D003094:Collagen