Eugenio Velasco Ortega

Crestal bone loss related to immediate implants in crestal and subcrestal position: a pilot study in dogs

OBJECTIVESnThe aim of the present study was to compare crestal bone loss with different implant designs inserted immediately in crestal or subcrestal position in post-extraction sockets in a dog model.nnnMATERIALS AND METHODSnThe mandibular second, third, fourth premolars, and the first molars of six adult fox hound dogs were extracted bilaterally, and 48 implants were placed immediately in both hemi-arches of each dog. Randomly, eight implants (sky classic (®) and blue sky (®) ) were inserted, four crestally (control group) and four 2xa0mm subcrestally (test group). Both groups were treated with a minimal mucoperiosteal flap elevation approach. After a 12-week healing period, the animals were sacrificed, and samples were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out to compare buccal and lingual bone height loss.nnnRESULTSnAll implants were clinically and histologically osseointegrated. Healing patterns examined microscopically at eight and 12xa0weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. At 12xa0weeks, the distance from the top of the implant collar to the first BIC (ISBc) showed significant difference between implant positions (crestal or subcrestal) in the buccal aspect (Pxa0=xa00.1253), values for the crestal group being higher (1.79xa0±xa00.3xa0mm) in comparison with the subcrestal group (0.89xa0±xa00.5xa0mm). Better results were achieved by both implant designs when implants were placed in the deeper position. No significant differences were found in BIC values (Pxa0>xa00.05). The total BIC at 8xa0weeks was (46.22xa0±xa04.29%) for the crestal group and (49.72xa0±xa02.21%) for the subcrestal group; at 12xa0weeks, it was (41.54xa0±xa03.87%) for the crestal group and (56.87xa0±xa03.46%) for the subcrestal group.nnnCONCLUSIONSnWithin the limitations of this study, the findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri-implant tissue remodeling. However, less resorption of the lingual and buccal crest may be expected when implants are placed 2xa0mm subcrestally, but this is not related to implant design. Moreover, implants placed subcrestally produced better bone-to-implant contact measurements.

Graft Materials in Oral Surgery: Revision

Oral implantology is a common procedure in dentistry, especially for fully or partially edentulous patients. The implants must be placed in the best location from both the aesthetic and functional point of view. Because of this it is increasingly more frequent to resort to regeneration techniques that use substitutes of the bone itself, in order to be able to insert the implants in the most appropriate location. nMaterial and Methodology: A review was performed on the literature from the last ten years based on the following search limitations: “graft materials, allograft, xenograft, autologous graft” and dentistry”. nResults: 241 works were obtained that after reading their respective summaries, they were reduced to 38, and 9 previous works were included in order to summarize the concepts. nDiscussion: Autologous grafts are the gold standard of the bone regeneration. They have obvious advantages, but they also have drawbacks. This is why allogeneic and xenogeneic tissues are used. The former because of their clear similarity with the recipients tissue and the latter due to their wide availability. Given that these grafts also have drawbacks, the industry has developed synthetic materials that have properties similar to those of human bone tissue. However, as of today, the ideal material to substitute human bone has not yet been found. In recent years the tendency has been to combine these synthetic materials with the patients own bone, which is extracted during drilling in implant placement, with bone marrow aspiration, or with bone morphogenetic proteins. Thus the intention is to equip these substances with the osteogenic capacity. nConclusions: There is currently no ideal graft material, with the exception of those materials that come directly from the patient. We hope that in the coming years we will have products that will allow us to perform rehabilitations with better results and provide a better quality of life for our patients, especially those who have more complex situations to resolve, like the patients that are operated on for head and neck cancer.