Vertical ridge augmentation using xenogenous bone blocks: a histomorphometric study in dogs.
OBJECTIVE
Because vertical ridge augmentation with autogenous bone blocks carries with it a risk of graft resorption and donor site morbidity, the aim of the present study was to compare histologically the healing following vertical ridge augmentation using screwable, xenogenous deproteinized blocks or autologous bone blocks in dogs.


METHODS
Standardized vertical mandibular defects were surgically created in edentulous ridges of six foxhounds. Two bone blocks (6 x 10 x 15 mm) were inserted on each mandibular side and fixed with both a titanium implant and an osteosynthetic screw. Three different therapies were tested: (1) xenogenous block alone; (2) xenogenous block, covered with a chemically cross-linked collagen membrane; and (3) autologous blocks, harvested during defect preparation. After 3 months of submerged healing, the miniscrews were removed and replaced by dental implants. Following an additional healing period of 3 months, the animals were sacrificed, and dissected blocks were prepared for histomorphometric analysis.


RESULTS
During the primary healing period, three of 12 hemimandibles (six blocks) had to be removed because of severe inflammatory reactions (two xenogenous block sites with collagen membrane, one autologous block site). In general, histologic analysis revealed that xenogenous blocks, used alone or combined with a collagen membrane, exhibited osteoconductive properties on a level equivalent to that of autologous blocks, resulting in means of 50% to 60% of ossification of the blocks. Some parts of the xenograft were encased in soft tissue, partly surrounded by multinuclear giant cells. However, all groups showed obvious signs of bone/graft resorption.


CONCLUSIONS
Within the limits of the present study, it was concluded that the examined screwable xenogenous bone block might be a useful scaffold for ridge augmentation procedures. However, the combination of xenogenous blocks with a cross-linked collagen membrane did not appear to improve outcomes.
Rothamel
Daniel
D
Department of Oral Surgery, Heinrich Heine University, Düsseldorf, Germany. daniel.rothamel@uk-koeln.de
Schwarz
Frank
F
Herten
Monika
M
Ferrari
Daniel
D
Mischkowski
Robert A
RA
Sager
Martin
M
Becker
Jürgen
J
D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use*; D016025:Bone Transplantation / Q000379:methods*; D003758:Dental Implantation, Endosseous / Q000379:methods; D004195:Disease Models, Animal; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods; D006882:Hydroxyapatites / Q000627:therapeutic use; D007575:Jaw, Edentulous / Q000601:surgery; D008334:Mandible / Q000601:surgery*; D008567:Membranes, Artificial; D008903:Minerals / Q000627:therapeutic use*; D013516:Oral Surgical Procedures, Preprosthetic / Q000379:methods*; D016348:Osseointegration / Q000187:drug effects / Q000502:physiology; D011897:Random Allocation; D014716:Vertical Dimension
C077540:Bio-Oss; D018786:Bone Substitutes; D006882:Hydroxyapatites; D008567:Membranes, Artificial; D008903:Minerals