title: Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste.
abstract: OBJECTIVE
  The aim of the study was to clinically and histologically evaluate the healing of human intrabony defects treated with open flap surgery (OFD) and application of a new, resorbable, fully synthetic, unsintered, nanocrystalline, phase-pure hydroxyapatite (nano-HA).
  
  
  METHODS
  Six patients, each of them displaying very advanced intrabony defects around teeth scheduled for extraction due to advanced chronic periodontitis and further prosthodontic considerations, were included in the study. Following local anaesthesia, mucoperiosteal flaps were reflected; the granulation tissue was removed, and the roots were meticulously debrided by hand and ultrasonic instruments. A notch was placed at the most apical extent of the calculus present on the root surface or at the most apical part of the defect (if no calculus was present) in order to serve as a reference for the histological evaluation. Following defect fill with nano-HA, the flaps were sutured by means of mattress sutures to allow primary intention healing. At 7 months after regenerative surgery, the teeth were extracted together with some of their surrounding soft and hard tissues and processed for histological analysis.
  
  
  RESULTS
  The postoperative healing was uneventful in all cases. At 7 months following surgery, mean PPD reduction and mean CAL gain measured 4.0 ± 0.8 and 2.5 ± 0.8 mm, respectively. The histological analysis revealed a healing predominantly characterized by epithelial downgrowth. Limited formation of new cementum with inserting connective tissue fibers and bone regeneration occurred in three out of the six biopsies (i.e. 0-0.86 and 0-1.33 mm, respectively). Complete resorption of the nano-HA was found in four out of the six biopsies. A few remnants of the graft particles (either surrounded by newly formed mineralized tissue or encapsulated in connective tissue) were found in two out of the six biopsies.
  
  
  CONCLUSIONS
  Within their limits, the present results indicate that nano-HA has limited potential to promote periodontal regeneration in human intrabony defects.
  
  
  CONCLUSIONS
  The clinical outcomes obtained following surgery with OFD + nano-HA may not reflect true periodontal regeneration.
authors.affiliation: Department of Periodontology, Semmelweis University, Budapest, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Horváth
authors.forename: Andreas
authors.initials: A
authors.lastname: Stavropoulos
authors.forename: Péter
authors.initials: P
authors.lastname: Windisch
authors.forename: László
authors.initials: L
authors.lastname: Lukács
authors.forename: István
authors.initials: I
authors.lastname: Gera
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000473:pathology / Q000601:surgery*; D000539:Alveolar Process / Q000473:pathology*; D001861:Bone Regeneration / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use*; D002113:Calcification, Physiologic / Q000502:physiology; D025021:Cementogenesis / Q000502:physiology; D055113:Chronic Periodontitis / Q000601:surgery; D003238:Connective Tissue / Q000473:pathology; D017886:Durapatite / Q000627:therapeutic use*; D004848:Epithelium / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053758:Nanoparticles / Q000627:therapeutic use*; D010012:Osteogenesis / Q000502:physiology; D017622:Periodontal Attachment Loss / Q000473:pathology / Q000601:surgery; D010514:Periodontal Pocket / Q000473:pathology / Q000601:surgery; D013357:Subgingival Curettage / Q000379:methods; D013524:Surgical Flaps / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018786:Bone Substitutes; D017886:Durapatite