Sinus augmentation analysis revised: the gradient of graft consolidation.
OBJECTIVE
Graft consolidation follows a gradient that reflects the properties of bone substitutes at sites of sinus augmentation. Here we present an analytical method to investigate the process of graft consolidation taking the distance from the maxillary host bone into account.


METHODS
We therefore evaluated histological specimens, 6 and 12 weeks after the sinus of minipigs was augmented with Bio-Oss((R)), a deproteinized bovine bone mineral, and Ostim((R)), an aqueous paste of synthetic nanoparticular hydroxyapatite. A curve was drawn that represents the changes in histomorphometric parameters within a given distance from the maxillary host bone.


RESULTS
Based on this curve, three regions of interest were defined: R1 (0-1 mm) the bridging distance where new bone is laid onto the host bone, R2 (2-3 mm) a region of osteoconduction where new bone exclusively grows on the biomaterial, R3 (4-5 mm) and a region of osteoconduction where bone formation has reached its maximal extension. Qualitative and quantitative analysis of the three regions can reveal differences in graft consolidation, depending on the bone substitutes and the observation period [Bone volume (BV) per tissue volume after 6 weeks: R1: 19+/-8.4% for Bio-Oss((R)) and 42.9+/-13.2% for Ostim((R)) (P=0.03), R2: 3+/-2.4% for Bio-Oss((R)) and 14.7+/-9.5% for Ostim((R)) (P=0.03), R3: 5+/-4.1% for Bio-Oss((R)) and 5.3+/-5.3% for Ostim((R)) (P=0.86). BV per tissue volume after 12 weeks: R1: 38.0+/-13.3% for Bio-Oss((R)) and 53.3+/-6.6 for Ostim((R)) (P=0.04), R2: 14+/-12.2 for Bio-Oss((R)) and 26.4+/-11 for Ostim((R)) (P=0.18), R3: 6.6+/-7 for Bio-Oss((R)) and 10.7+/-5.8 for Ostim((R)) (P=0.32) after 12 weeks].


CONCLUSIONS
Based on the graft consolidation gradient, the impact of bone substitutes to modulate the process of bone formation and the kinetic of degradation within a distinct region of the augmented sinus can be investigated.
Busenlechner
Dieter
D
Department of Oral Surgery, Medical University of Vienna, Vienna, Austria.
Huber
Christian D
CD
Vasak
Christoph
C
Dobsak
Antonia
A
Gruber
Reinhard
R
Watzek
Georg
G
D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects* / Q000502:physiology; D016723:Bone Remodeling / Q000187:drug effects / Q000502:physiology; D018786:Bone Substitutes / Q000494:pharmacology*; D002417:Cattle; D006882:Hydroxyapatites / Q000494:pharmacology; D008137:Longitudinal Studies; D008437:Maxilla / Q000502:physiology / Q000601:surgery*; D008443:Maxillary Sinus / Q000601:surgery; D008903:Minerals / Q000494:pharmacology; D008954:Models, Biological; D053758:Nanoparticles; D016348:Osseointegration / Q000187:drug effects* / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D013552:Swine; D013556:Swine, Miniature
C077540:Bio-Oss; D018786:Bone Substitutes; D006882:Hydroxyapatites; D008903:Minerals