title: Implant treatment in atrophic posterior mandibles: vertical regeneration with block bone grafts versus implants with 5.5-mm intrabony length.
abstract: OBJECTIVE
  To retrospectively compare the outcomes of implants placed in posterior mandibles vertically regenerated with onlay autogenous block bone grafts and short dental implants.
  
  
  METHODS
  Consecutive patients with vertical bone atrophy in edentulous mandibular posterior regions (7 to 8 mm of bone above the inferior alveolar nerve) were treated with either implants placed in regenerated bone using autologous block bone grafts (group 1) or short implants (with 5.5-mm intrabony length) in native bone (group 2) between 2005 and 2010 and followed for 12 months after loading. The procedure used was the established treatment protocol for this type of patient at the Oral Surgery Unit (University of Valencia, Spain) at the time of surgery. All grafts were obtained using piezosurgery. The outcomes assessed were: complications related to the procedure, implant survival, implant success, and peri-implant marginal bone loss. Statistical analysis was done using the Fisher exact test and the Mann-Whitney test.
  
  
  RESULTS
  Thirty-seven patients were included, 20 (45 implants) in group 1 and 17 (35 implants) in group 2. In group 1, 13 implants were less than 10 mm long (2 were 7 mm and 11 were 8.5 mm), and 32 were 10 mm or longer; the diameter was 3.6 mm in 6 implants, 4.2 mm in 31, and 5.5 mm in 8. In group 2 all implants were 7 mm long; the diameter measured 4.2 mm in 14 implants and 5.5 mm in 21 implants. Complications related to the block bone grafting procedure were temporary hypoesthesia in one patient, wound dehiscence with graft exposure in three patients, and exposure of the osteosynthesis screw without bone graft exposure in one patient. After 12 months, implant survival rates were 95.6% in group 1 and 97.1 % in group 2; success rates were 91.1% and 97.1%, respectively. The average marginal bone loss was 0.7 ± 1.1 mm in group 1 and 0.6 ± 0.3 mm in group 2.
  
  
  CONCLUSIONS
  When residual bone height over the mandibular canal is between 7 and 8 mm, short implants (with 5.5-mm intrabony length) might be a preferable treatment option over vertical augmentation, reducing chair time, expense, and morbidity.
authors.forename: David
authors.initials: D
authors.lastname: Peñarrocha-Oltra
authors.forename: Amparo
authors.initials: A
authors.lastname: Aloy-Prósper
authors.forename: Juan
authors.initials: J
authors.lastname: Cervera-Ballester
authors.forename: Maria
authors.initials: M
authors.lastname: Peñarrocha-Diago
authors.forename: Luigi
authors.initials: L
authors.lastname: Canullo
authors.forename: Miguel
authors.initials: M
authors.lastname: Peñarrocha-Diago
mesh_terms: D000328:Adult; D016301:Alveolar Bone Loss / Q000534:rehabilitation* / Q000601:surgery; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D018786:Bone Substitutes / Q000627:therapeutic use; D016025:Bone Transplantation / Q000379:methods*; D003758:Dental Implantation, Endosseous / Q000379:methods* / Q000706:statistics & numerical data; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation* / Q000601:surgery; D008297:Male; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008336:Mandibular Diseases / Q000534:rehabilitation* / Q000601:surgery; D008875:Middle Aged; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
chemical_list: D018786:Bone Substitutes