Application of Bio-Oss in tissue regenerative treatment prior to implant installation: literature review

Alessandra de Carvalho MOREIRA1, Jhenifer Rodrigues SILVA1, Renata de Paula SAMICO2, Gabriela Nogueira de Melo NISHIOKA2, Renato Sussumu NISHIOKA2 1 – São Paulo State University (Unesp) – Institute of Science and Technology São José dos Campos – SP Brazil. 2 – São Paulo State University (Unesp) – Institute of Science and Technology, São José dos Campos – São José dos Campos – Department of Dental Materials and Prosthodontics – SP – Brazil. doi: 10.14295/bds.2019.v22i2.1691 UNIVERSIDADE ESTADUAL PAULISTA “JÚLIO DE MESQUITA FILHO”


INTRoDuCTIoN
O ne of the dentist's challenges in surgical clinical practice, is to deal with bone reconstruction that comes after trauma, infection, neoplasies or periodontal disease [1]. The use of bone grafts aims to improve bone regeneration after surgical procedures and works as a support to blood clot, reducing the risk of soft tissue breakdown in the bone defects [2].
Bone grafts can be classified as autogenous, harvested from donor site of the patient itself; homologous, when collected in the same species, but different individuals; xenogene, when collected in different species; alloplastic, when formed by a laboratory developed synthetic material [3,4].
The characteristics of an ideal bone graft material are: can be gradually replaced by newly formed bone, have osteoconductive or osteoinductive properties [5], be biocompatible and easy to manage during surgical procedures [6].
Autogenous grafts are considered "gold standard" due to its osteogenic, osteoconductive and osteoinductive properties [7]. Its predictability is the main choosing fator, concerning that is the only one that offers to the receiver site, cells with growth factors and with bone neoformation properties [8]. Their disadvantages are associated to a higher post operative morbidity, donor site availability, unforseen graft resorption, and many times, the need of extraoral harvesting sites. [9,10].
With the focus on overcome such limitations and in association with high scientific and technological development, the biomaterials have arised as an altertative to the use of autogenous grafts [11].
Bovine biomaterials are used as a bone replacement material and have been studied since the 60's. Bio-Oss (Geistlich) is a xenogene bone graft, which all the organic compounds are removed, maintaining its natural mineral architecture. Its structure is physically and chemically comparable to the mineralized matrix of human bone [12]. Besides, presentes the advantage towards the autogenous bone graft the fact of being slowly reabsorbed, acting as a scaffold to new bone formation during all the regenerative process [10,13,14].
Concerning the researches that have been developed, it was examined that there are previous studies about this theme, being one of the most studied materials owing to its proven osteoconductive properties [13][14][15][16][17]. However, few recent studies were found, being required a new literature review that approaches the advantages of using Bio-Oss (Geistlich) and the case report that assures its efficacy in clinical practice. Therefore, the aim of this study was to evaluate through a litetature review the benefits of Bio-Oss to regenerative tissue treatment previously to implants placement.

mATeRIAl AND meThoDS
A search into PubMed (MEDLINE) was made in order to identify scientific articles in english, published between January 1st, 2000 to 31st of june 2018, where the use of Bio-Oss used previouly to implant placement was performed. The search was made using the key-words: Bio-Oss, dental implants, bone grafts, implant, human, bone transplantation.
The initial search resulted in 262 articles. Therefore, after title and abstract critical reading, some studies were excluded because they found to be incompatible to the objective of this study, and 40 articles were selected to a detailed analysis. From this analysis, 18 articles were finally selected to be included in this review, and only randomized controlled trials.

ReSulTS
The results of the bibliographic research were presented through the Table 1 bellow that demonstrated the main features of the articles selected in this study.

Autor
Objective Follow-up period Benefits of Bio-Oss usage Investigate, through an imune-histochemical method, patterns of deproteinized bovine bone remodelling in humans.
Five months.
• Osteointegration process • Newly formed bone tissue between graft particles.
• Keeps the activity in bone remodelling process.
• Confirms the bioconductive properties of Bio-Oss Investigate the histological patterns and implant survival rates 5 years after maxillary sinus grafting with bovine inorganic bone graft (Bio-Oss) and Bio-Oss with autogenous bone with 1/1 proportion.
Five years and two months.
• The isolated use of Bio-Oss avoids donor site mobidity.
• Suitable for bone preservation and long term sucess.
Meloni SM et al.(2015) [20] Test the hypothesis that the placed implants in maxillary sinus grafted with bovine inorganic bone graft (Bio-Oss) presented comparable results to those that were grafted with bovine and autologous graft.
Twelve months.
• Investigate histologically and histomorphometrically human biopsies when Bio-Oss was used alone in surgical practice enviroment to maxillary sinus lifting procedures.
Twenty months.
• Confirms its osteoconductives properties and it is suitable for bone defects treatments and maxillary sinus grafting • Bio-Oss used alone showed a implant sucess rate of 100% after 12 months of loading. • Behaved as a scaffold through which newbone was formed. • Intimate contact between Bio-Oss particles and newly formed bone without gaps in the interface. • Confirms its good biocompatibility • There were no negative effects presented with the use of Bio-Oss. Evaluate the long-term survival rate of wide platform implants placed in maxillarysinus grafted with deproteinized bovine bone graft (Bio-Oss; Geistlich Pharma AG, Wolhusen, Switzerland ).
Nine years.
• Confirms that Bio-Oss is biocompatible and osteoconductive.
• Particles of Bio-Oss remans many years after bone graft placement. • The long term maintainance of Bio-Oss, as long as provides suport and density, doesn't interfere in osteointegration process. • Better survival rates of the implant when Bio-Oss was used as the only bone graft material • High long-term survival rates of implants, placed in areas where Bio-Oss was used. Evaluate the sucess rate1 year after loading of early loaded implants, placed in vertically increased bone , using deproteinized bovine bone graft (Bio-Oss) and a titaniumreinforced membrane (Gore-Tex) Two years.
• Its slow resorption may be pointed as a positive finding, suggesting long term stability of regenerated tissue. • The Bio-Oss particles remained very close to alveolar bone. • Excelente sucess rate with acceptable peri-implant bone loss after a year of function Mardas N, Chadha V, Donos N. (2010) [31] Compare the potential of a synthetic bone substitute or a bovine xenograft combined with a collagen membrane to preserve alveolar ridge dimensions after teeth extraction.
Eight months.
• Confirmed its osteoconductivity and new bone formation.
• Approved to treat peri-implant defects of deiscency.
• Partially preserved bone width and height of alveolar crest, allowing implant placement.
Pietro F. et al.
(2008) [32] Compare efficacy, complications and patients preference over two different techniques of bone height increasement in posterior mandibular region :bone blocks harvested from illiac crest versus inorganic bovine bone blocks (Bio-Oss) used as inlays.
Five years and eight months.
• Using Bio-Oss is preferable than harvesting bone fro illiac crest.
• The sides that undergone vertical height increasement with a bone substitute recovered sensitiveness faster than the sides treated with autogenous bone.
• Demonstrated that resorption occured very slowly.
• Avoid surgical procedures of autogenous bone harvesting.
• Showed intimate contact between xenograft and newly formed bone Steigmann M.(2008) [34] Report the use of a mineral block of bovine bone combined with a resorbable collagen membrane to increase a vertically and horizontally .
Three years and six months.
• Due to its slow remodelling process it mantains its volume during a long period of time. • Garantees interproximal bone height stability untill implants can be functionally loaded. • Suitable for severe deficiencies enhancement. Valentini P, Abensur D, Wenz B, Peetz M, Schenfe R.(2000) [35] Evaluate efficacy of Bio-Oss in the contexto of a clinical and histomorphometric study.
Two years.
• Confirms to be a good osteoconductive materialthat leadsto effective osteointegration of dental implants • Indicates high level of calcification suggesting an intimate contact between itself and newly formed bone. • Indicates a very slow resorption of grafting material. • Can be sucessfully used in maxillary sinus grafting.

DISCuSSIoN
The reconstruction of bone deformities, by trauma, infection, neoplasies or periodontal disease is one of challenges for the dentist [1]. On the other hand of this statement, the use of bone grafts allows to guide bone regeneration after a surgical procedure.
Bio-Oss is a bone substitute of bovine origin (xenograft), in which all the organic components are extracted, supporting the natural bone architecture. Due to its structure, Bio-Oss is phisically and chemically comparable to mineralized matrix of human boné [12].This material is highly referredin literature owing to its osteoconductive qualities, high biocompatibility, and proficiency related to autogenous bone graft in undergoing slower resorption , serving as a scaffold to bone neoformation during regenerative process [13,14,10].
The histological findings demonstrate that the Bio-Oss particles are connected between each other through bone bridges and covered by newly formed bone tissue [25][26][27]31] [27,26].
Was compared the potential of a synthetic bone substitute related to the bovine origin xenograft on preserving bone dimensions. As a result, both grafts preserved all clinical dimensions of the site, giving support to new bone formation, and allowing the placement of dental implants [31].
In respect of Bio-Oss employment, researches report higher survival rates of the implant, when the graft was used isolatedly [22,36],showing predictable long-term clinical results [21].
The slow resorption oh the bovine xenograft, is considered a positive characteristic, suggesting long term stablity of regenerated tissue [30,35].
The slow remodelling process, maintains the volume during a longer period of time, corroborating to the persistance of interproximal bone height in the grafted site untill implants are functionally loaded and natural bone remodelling occurs [34].
Due to its limited biodegradation, the hyphotesis is that Bio-Oss is a prerrogative to bone preservation and long-term implant sucess [19] .
Bio-Oss is widely used in maxillary sinus grafting . Accordingly to several studies, patients treated with implants after procedures of maxillary sinus grafting with xenograft, presented a great clinical response, ratifying the assertivity of material usage for grafting procedures in those sites [19,20,25,26,35].
Cordoraro et al. [33] confirmed the advantage of using xenograft (Bio-Oss) because it provides confort to patient and surgeon, in spite of surgery is restrained to the host site, avoiding bone harvesting procedures that are necessary to use autogenous graft.
Accordingly to Schmitt et al. [19], the addition of autogenous bone together with Bio-Oss has no beneficial effect when compared to isolated use of Bio-Oss in the maxillary sinus grafting. Therefore, these authors preach the isolated use of Bio-Oss, because the same avoids the harvesting of autogenous bone, decreasing the possible patient morbidity.
In spite of the numerous benefits of Bio-Oss already mentioned, it has some disadvantages, such as the time between grafting and its integration into the recipient bed, which can vary from 6 to 10 months, which may stimulate the search for its association with other substances that accelerate the local bone neoformation [37].
Hallman et al. shows in his study that a longer healing period is required for the maxillary sinus grafted only with Bio-Oss because the new bone proliferation occurs only from the peripheral walls of the bone, so the addition of autogenous bone along with Bio-Oss facilitates the proliferation of vessels and tissues; thus, new bone formation and incorporation of the grafts takes less time to heal.

CoNCluSIoN
It is concluded that the use of bio-oss as a bone substitute is a viable alternative in the placement before dental implants, being used in clinical practice and with proved efficacy in several studies, due to its similarity with the bone and its high level of osteoconductivity.