title: Dimensional changes in soft tissues around dental implants following free gingival grafting: an experimental study in dogs.
abstract: OBJECTIVE
  To study the buccal dimensional tissue changes at oral implants following free gingival grafting, with or without including the keratin layer, performed at the time of implant installation into alveolar mucosa.
  
  
  METHODS
  The mandibular premolars and first molars were extracted bilaterally in six Beagle dogs. In the right side of the mandible (Test), flaps were first elevated, and the buccal as well as part of the lingual masticatory mucosa was removed. An incision of the periosteum at the buccal aspect was performed to allow the flap to be coronally repositioned. Primary wound closure was obtained. In the left side, the masticatory (keratinized) mucosa was left in situ, and no sutures were applied (Control). After 3 months of healing, absence of keratinized mucosa was confirmed at the test sites. Two recipient sites were prepared at each side of the mandible in the region of the third and fourth premolars. All implants were installed with the shoulder placed flush with the buccal alveolar bony crest, and abutments were connected to allow a non-submerged healing. Two free gingival mucosal grafts were harvested from the buccal region of the maxillary canines. One graft was left intact (gingival mucosal graft), while for the second, the epithelial layer was removed (gingival connective tissue graft). Subsequently, the grafts were fixed around the test implants in position of the third and fourth premolars, respectively. After 3 months, the animals were euthanized and ground sections obtained.
  
  
  RESULTS
  Similar bony crest resorption and coronal extension of osseointegration were found at test and control sites. Moreover, similar dimensions of the peri-implant soft tissues were obtained at test and control sites.
  
  
  CONCLUSIONS
  The increase in the alveolar mucosal thickness by means of a gingival graft affected the peri-implant marginal bone resorption and soft tissue recession around implants. This resulted in outcomes that were similar to those at implants surrounded by masticatory mucosa, indicating that gingival grafting in the absence of keratinized mucosa around implants may reduce the resorption of the marginal crest and soft tissue recession.
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba.
authors.forename: Franco
authors.initials: F
authors.lastname: Bengazi
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
authors.forename: Marino
authors.initials: M
authors.lastname: Caroprese
authors.forename: Joaquin
authors.initials: J
authors.lastname: Urbizo Velez
authors.forename: Vittorio
authors.initials: V
authors.lastname: Favero
authors.forename: Daniele
authors.initials: D
authors.lastname: Botticelli
mesh_terms: D016301:Alveolar Bone Loss; D000539:Alveolar Process; D000818:Animals; D001641:Bicuspid; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D004285:Dogs; D005881:Gingiva / Q000637:transplantation*; D008334:Mandible / Q000601:surgery; D008963:Molar; D009061:Mouth Mucosa / Q000637:transplantation*; D016348:Osseointegration; D013524:Surgical Flaps; D014081:Tooth Extraction; D016896:Treatment Outcome; D014945:Wound Healing
keywords: alveolar mucosa; animal study; connective tissue; dental implants; dimensional changes; free gingival graft; grafting; histology; implant dentistry; masticatory mucosa