title: Radiographic alveolar bone changes following ridge preservation with two different biomaterials.
abstract: OBJECTIVE
  The aim of this randomized controlled trial was to evaluate radiographical bone changes following alveolar ridge preservation with a synthetic bone substitute or a bovine xenograft.
  
  
  METHODS
  Alveolar ridge preservation was performed in 27 patients randomized in two groups. In the test group (n=14), the extraction socket was treated with Straumann bone ceramic(®) (SBC) and a collagen barrier membrane (Bio-Gide(®)), whereas in the control group (n=13) with deproteinized bovine bone mineral and the same barrier. Standardized periapical X-rays were taken at 4 time points, BL: after tooth extraction, GR: immediately after socket grafting, 4M: 16 weeks, 8M: 32 weeks post-operatively. The levels of the alveolar bone crest at the mesial (Mh), and distal (Dh) and central aspects of the socket were measured at all time points. All the radiographs obtained were subtracted from the follow-up images. The gain, loss and unchanged areas in terms of grey values were tested for significant difference between the two groups.
  
  
  RESULTS
  In the test group, the Mh and Dh showed a mean difference (± standard deviation) of 0.9 ± 1.2 and 0.7 ± 1.8 mm, respectively, among BL-8M. In the control group, the Mh and Dh showed a mean difference of 0.4 ± 1.3 and 0.7 ± 1.3 mm, respectively (P>0.05). Both treatments presented similar gain in grey values between BL-GR, BL-4M and BL-8M. The SBC presented less loss in grey values between BL-4M and BL-8M (P<0.05). Radiographic assessment underestimated the intrasurgical measurements (mesial and distal) of an average 0.3 mm (95% CI, 0.02-0.6).
  
  
  CONCLUSIONS
  Both types of bone grafts presented similar radiographic alveolar bone changes when used for alveolar ridge preservation.
authors.affiliation: Periodontology Unit, Eastman Dental Institute, University College London, London, UK. n.mardas@eastman.ucl.ac.uk
authors.forename: Nikos
authors.initials: N
authors.lastname: Mardas
authors.forename: Francesco
authors.initials: F
authors.lastname: D'Aiuto
authors.forename: Luis
authors.initials: L
authors.lastname: Mezzomo
authors.forename: Marina
authors.initials: M
authors.lastname: Arzoumanidi
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Donos
mesh_terms: D020341:Absorbable Implants; D016301:Alveolar Bone Loss / Q000209:etiology / Q000517:prevention & control*; D000539:Alveolar Process / Q000000981:diagnostic imaging*; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D018786:Bone Substitutes; D016025:Bone Transplantation; D003094:Collagen; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D016014:Linear Models; D008567:Membranes, Artificial; D019252:Radiography, Dental, Digital / Q000379:methods; D015203:Reproducibility of Results; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D013382:Subtraction Technique; D014081:Tooth Extraction / Q000009:adverse effects; D020390:Tooth Socket / Q000000981:diagnostic imaging / Q000601:surgery
chemical_list: C106416:Bio-Gide; D018786:Bone Substitutes; D008567:Membranes, Artificial; D003094:Collagen