Often times, dental implant placement is complicated by inadequacy of bone volume due to tooth loss, periodontal disease, pathology, or trauma. However, more challenging implant cases are being performed due to the advancement in bone augmentation procedures and materials to augment deficient alveolar bone.1
Autogenous bone is considered to be the “gold standard”, for alveolar ridge regeneration, due to its osteogenicity.1,2 However, autogenous bone grafts are associated with rapid rate of resorbtion3 and donor site morbidity1. This has led scientists to investigate allogenic and xenogenic bone grafts, as well as alloplastic materials, such as Hydroxyapatite and Calcium Phosphate Compounds.4
An alternative to autogenous bone is xenograft. Although xenografts have provided acceptable results, they are considered to be inferior in bone generation potential when compared to autografts. However, the supply of xenograft is unlimited. Xenografts are usually derived from bovine origin.5
Bio-Oss® (Geistlich Pharmaceutical, Walhusen, Switzerland) is a natural bovine bone derivative that lacks the organic component.6 Bio-Oss® and mineralized human bone are similar in their chemical and morphological structures.2 Bio-Oss® granules are 0.25 to 1.00 mm in diameter.6 Due to its porous structure, Bio-Oss® occupies 25-30% of the defect space initially.7 This facilitates angiogenesis (penetration of the bone augmentation material by blood vessels) and osteoblast migration.8
Along with all of its potential properties, the osteoconductive nature of Bio-Oss® when used as an onlay graft is not well established. The Osteoconductivity of Bio-Oss® has been a topic of debate in the literature.
It is well known that an onlay bone graft is more challenging to maintain clinically than an inlay bone graft. Rosenthal el al demonstrated that onlay bone grafts showed resorption with time, while inlay bone grafts showed increased volumes overtime.9 Increased bone to bone contact between the inlay bone graft and the native bone is one explanation to this difference. Another explanation is the fact that inlay bone grafts are surrounded by biological boundaries. This shields them from recoil forces of the surrounding soft tissue. In addition, inlay bone grafts receive identical physical stresses to those received by the surrounding bone.9
Some studies described Bio-Oss® as having osteoconductive properties. In an experiment involving the skull of the rabbit, using histomorphometric analysis, Slotte et al examined the bone formation in titanium cylinders filled with either autogenous bone or Bio-Oss® as compared to empty titanium cylinders as controls. Significantly more bone tissue was found in the two test groups than the control group.10
Other studies claimed that Bio-Oss® is not osteoconductive when used as an onlay. In an experiment involving the skull of the rat, Slotte and Lundgren studied, histomorphometrically, the bone generation potential of silicone domes grafted with Bio-Oss® compared to empty ones.11 The study demonstrated that Bio-Oss® arrested bone formation.
In two different studies using the mandible of the rat, Stavropoulos et al studied the amount of bone generation in Teflon capsules grafted with Bio-Oss® as compared to empty (control) capsules. The capsules were fixed to the mandible using suture material. In both experiments, it was shown that Bio-Oss® had an inhibitory effect on bone formation.12,13
Such results and the results of other studies have lead some authors to suggest that dental implant survival in grafted sites may be owed mainly to the function of the native bone rather than the bone graft itself.14
Araújo et al found that Bio-Oss resulted in less bone generation than autogenous bone when used as an onlay in dogs’ mandibles.15 However, they found that Bio-Oss maintained more volume than autogenous bone did. Due to this fact, some authors suggested the use of Bio-Oss mainly to preserve the architecture of the soft tissue.16
From the discussion above, in my opinion, the use of Bio-Oss an onlay bone substitute may not have a significant value in bone generation potential, but it may add some value to the way it supports the soft tissue profile. This feature may give the implant a better esthetic outcome.
1- Norton M, Odell EW, Thompson ID, Cook RJ. Efficacy of bovine bone mineral for alveolar augmentation: a human histologic study. Clinical Oral Implant Research. 2003; 14: 775-783
2- Ewers R, Goriwoda W, Schopper C, Moser D, Spassova E. Histologic findings at augmented bone areas supplied with different bone substitute materials combined with sinus floor lifting. Report of one case. Clinical Implant Research. 2004; 15: 96-100.
3- Johansson, B., Grepe, A., Wannfors, K. & Hirsch, J-M. (2001) A clinical study of changes in the volume of bone grafts in the atrophic maxilla. Dentomaxillofacial Radiology 30: 157-161.
4- Hämmerle, C.H., Chiantella, G.C., Karring, T. & Lang, N.P. (1998) The effect of a deproteinized bovine bone mineral on bone regeneration around titanium dental implants. Clinical Oral Implants Research 3: 151-162.
5- Tuominen, T., Jäsmä, T., Tuukkanen, J., Marttinen, A., Lindholm, T.S. & Jalovaara, P. (2001) Bovine bone implant with bovine bone morphogenetic protein in healing a canine ulnar defect. International Orthopaedics 25(1): 5-8.
6- Hising, P., Bolin, A. & Branting, C. (2001) Reconstruction of severely resorbed alveolar ridge crests with dental implants using a bovine bone mineral for augmentation. The International Journal of Oral & Maxillofacial Implants 16(1): 90-97.
7- Peetz, M (1997) Characterization of xenogenic bone material. In: Boyne, P.J., ed. Osseous reconstruction of the maxilla and the mandible – surgical techniques using titanium mesh and bone mineral, 87-100. Chicago, Berlin: Quintessence.
8- Yildirim M, Spiekermann H, Biesterfeld S, Edelhoff D. Maxillary sinus augmentation using xenogenic bone substitute material Bio-Oss® in combination with venous blood. A histologic and histomorphometric study in humans. Clinical Oral Implant Research 2000: 11:217-229
9- Rosenthal, A.H. and S.R. Buchman, Volume maintenance of inlay bone grafts in the craniofacial skeleton. Plastic and reconstructiove surgey, 2003. 112(3) p.802811.
10- Slotte C, Lundgren D, Burgos PM. Placement of autogenic bone chips or bovine bone mineral in guided bone augmentation: A rabbit skull study. The International Journal of Oral & Maxillofacial implants, 2003; 18: 795-806
11- Slotte C, Lundgren D. Augmentation of calvarial tissue using non-permeable silicone domes and bovine bone mineral. An experimental study in the rat. Clinical Oral Implant Research 1999: 10: 468-476
12- Stavropoulos A, Kostopoulos L, Mardas N, Nyengaard JR, Karring T. Deproteinized bovine bone used as an adjunct to guided bone augmentation (GBA) An experimental study in the rat. Clinical Implant Dentistry and Related Research, 2001a; 3: 156-165
13- Stavropoulos A, Kostopoulos L, Nyengaard J R, Karring T. Deproteinized bovine bone (Bio-Oss®) and bioactive glass (Biogran®) arrest bone formation when used as an adjunct to guided tissue regeneration (GTR). An experimental study in the rat. Journal of Clinical Periodontology 2003; 30: 636-643
14- Aghaloo TL, Moy PK, Which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement? Int J Oral Maxillofac Implants. 2007; 22 Suppl:49-70.
15- Araújo MG, Sonohara M, Hayacibara R, Cardaropoli G, Lindhe J, Lateral ridge augmentation by the use of grafts comprised of autologous bone or a biomaterial. An experiment in the dog. J Clin Periodontol. 2002 Dec; 29(12):1122-31.
16- Schlee M, Esposito M, Aesthetic and patient preference using a bone substitute to preserve extraction sockets under pontics. A cross-sectional survey. Eur J Oral Implantol. 2009 Autumn; 2(3):209-17.
by Dr. Abdullah Al-Harkan