title: Biological width formation to immediate implants placed at different level in relation to the crestal bone: an experimental study in dogs.
abstract: OBJECTIVE
  Evaluate differences in bone remodeling, soft tissue reactions and biological width formation around immediate implants placed at different level in relation to the crestal bone in beagle dogs.
  
  
  METHODS
  The mandibular second, third and fourth premolars of six beagle dogs were extracted, and three implants were placed in the right side of each dog. Healing abutments were adjusted (n = 18). After 4 weeks, the procedure was repeated on the left side of the mandible (n = 18). Randomly, three implants were placed at crestal level (control group), and three implants were placed 2 mm subcrestally (test group) in relation to the crestal bone in each animal. The dogs were sacrificed after 8 weeks from the first surgical procedure, and biopsies were obtained. Samples were processed for ground sectioning. Histometric analysis was carried out to compare buccal and lingual bone resorption, soft tissue behavior and biological width formation in both groups.
  
  
  RESULTS
  Crestal bone resorption was higher in the test group when considering the difference of 2 mms (IS-B = 2.05 ± 0.36 mm, control; 1.75 (+2) ± 0.38 mm, test). However, the dimensions of the biological width were similar for both groups (PM-C = 3.34 ± 0.53 mm, control; 3.13 ± 0.55 mm, test).
  
  
  CONCLUSIONS
  The alterations that occurred in the peri-implant soft tissues may be related to the hard tissue remodeling, showing similar quantitative findings in the biological width formation in both groups. Even though the subcrestal placement might reduce the distance from the implant shoulder to the first bone-to-implant contact and reestablish the biological width dimension in a most coronal position, it might not have any effect on minimizing the marginal bone loss.
authors: Department of General Dentistry, Implants and Biomaterials, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
authors: Bruno
authors: B
authors: Negri
authors: Department of General Dentistry, Implants and Biomaterials, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
authors: Marta
authors: M
authors: López Marí
authors: Department of Restorative, Dentistry, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
authors: José Eduardo
authors: JE
authors: Maté Sánchez de Val
authors: Department of Biomaterials, Dental School, Chieti-Pescara University, Chieti, Italy.
authors: Giovanna
authors: G
authors: Iezzi
authors: Department of Orthodontics, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
authors: Luis Alberto
authors: LA
authors: Bravo González
authors: Department of General Dentistry, Implants and Biomaterials, Faculty of Medicine and Dentistry, University of Murcia, Murcia, Spain.
authors: José Luis
authors: JL
authors: Calvo Guirado
mesh_terms: D000539:Alveolar Process / Q000502:physiology* / Q000601:surgery; D000818:Animals; D001641:Bicuspid; D001706:Biopsy; D016723:Bone Remodeling / Q000502:physiology; D001862:Bone Resorption / Q000503:physiopathology; D015921:Dental Implants; D018772:Dental Marginal Adaptation; D004285:Dogs; D005881:Gingiva / Q000502:physiology*; D020007:Implants, Experimental; D008334:Mandible / Q000601:surgery*; D014945:Wound Healing / Q000502:physiology
chemical_list: D015921:Dental Implants
keywords: biological width; crestal bone; immediate implants; soft tissue