title: Surgical regenerative treatment of peri-implantitis lesions using a nanocrystalline hydroxyapatite or a natural bone mineral in combination with a collagen membrane: a four-year clinical follow-up report.
abstract: OBJECTIVE
  The present case series aimed at investigating the 4-year clinical outcomes following surgical regenerative therapy of peri-implantitis lesions using either a nanocrystalline hydroxyapatite (NHA) or a natural bone mineral in combination with a collagen membrane (NBM+CM).
  
  
  METHODS
  Twenty patients suffering from moderate peri-implantitis (n=20 intrabony defects) were randomly treated with (1) access flap surgery (AFS) and the application of NHA (n=9), or with AFS and the application of NBM+CM (n=11). Clinical and radiographic (R) parameters were recorded at baseline (R) and after 36 and 48 (R) months of non-submerged healing.
  
  
  RESULTS
  One patient from the NBM+CM group was discontinued from the study due to severe pus formation at 36 months. Compared with NHA, the application of NBM+CM resulted in higher mean PD reductions (NBM+CM: 2.5 +/- 0.9 mm versus NHA: 1.1 +/- 0.3 mm) and clinical attachment-level gains (NBM+CM: 2.0 +/- 1.0 mm versus NHA: 0.6 +/- 0.5 mm) at 48 months. A radiographic bone fill was observed for five sites in the NHA group, and eight sites in the NBM+CM group.
  
  
  CONCLUSIONS
  While the application of NBM+CM resulted in clinical improvements over a period of 4 years, the long-term outcome obtained with NHA without barrier membrane must be considered as poor.
authors.affiliation: Department of Oral Surgery, Westdeutsche Kieferklinik Heinrich Heine University, Düsseldorf, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Schwarz
authors.forename: Narja
authors.initials: N
authors.lastname: Sahm
authors.forename: Katrin
authors.initials: K
authors.lastname: Bieling
authors.forename: Jürgen
authors.initials: J
authors.lastname: Becker
mesh_terms: D020341:Absorbable Implants; D016301:Alveolar Bone Loss / Q000209:etiology / Q000601:surgery*; D001861:Bone Regeneration; D018786:Bone Substitutes; D003094:Collagen; D015921:Dental Implants / Q000009:adverse effects*; D017886:Durapatite; D005260:Female; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D008903:Minerals; D053758:Nanoparticles; D010518:Periodontitis / Q000209:etiology*; D016037:Single-Blind Method; D016896:Treatment Outcome
chemical_list: C106416:Bio-Gide; C077540:Bio-Oss; D018786:Bone Substitutes; D015921:Dental Implants; D008567:Membranes, Artificial; D008903:Minerals; D003094:Collagen; D017886:Durapatite