The Effects of Subcrestal Implant Placement on Crestal Bone Levels and Bone-to-Abutment Contact: A Microcomputed Tomographic and Histologic Study in Dogs

• Published in: The International journal of oral and maxillofacial implants Vol. 30; no. 5; p. 1068
• Main Authors: Fetner, Michael, Fetner, Alan, Koutouzis, Theofilos, Clozza, Emanuele, Tovar, Nick, Sarendranath, Alvin, Coelho, Paulo G, Neiva, Kathleen, Janal, Malvin N, Neiva, Rodrigo
• Format: Journal Article
• Language: English
• Published: United States 01.09.2015
• Subjects: Alveolar Bone Loss - diagnostic imaging; Alveolar Bone Loss - pathology; Alveolar Process - diagnostic imaging; Alveolar Process - pathology; Animals; Bone-Implant Interface - diagnostic imaging; Bone-Implant Interface - pathology; Dental Implant-Abutment Design; Dental Implantation, Endosseous - methods; Dental Implants; Dogs; Female; Image Processing, Computer-Assisted - methods; Imaging, Three-Dimensional - methods; Mandible - diagnostic imaging; Mandible - pathology; Mandible - surgery; Models, Animal; Osseointegration - physiology; Osteogenesis - physiology; Random Allocation; Time Factors; X-Ray Microtomography - methods
• ISSN: 1942-4434
• DOI: 10.11607/jomi.4043

Implant design and the implant-abutment interface have been regarded as key influences on crestal bone maintenance over time. The aim of the present study was to determine crestal bone changes around implants placed at different depths in a dog model. Thirty-six two-piece dental implants with a medialized implant-abutment interface and Morse taper connection (Ankylos, Dentsply) were placed in edentulous areas bilaterally in six mongrel dogs. On each side of the mandible, three implants were placed randomly at the bone crest, 1.5 mm subcrestally, or 3.0 mm subcrestally. After 3 months, the final abutments were torqued into place. At 6 months, the animals were sacrificed and samples taken for microcomputed tomographic (micro-CT) and histologic evaluations. Micro-CT analysis revealed similar crestal or marginal bone loss among groups. Both subcrestal implant groups lost significantly less crestal and marginal bone than the equicrestal implants. Bone loss was greatest on the buccal of the implants, regardless of implant placement depth. Histologically, implants placed subcrestally were found to have bone in contact with the final abutment and on the implant platform. Implants with a centralized implant-abutment interface and Morse taper connection can be placed subcrestally without significant loss of crestal or marginal bone. Subcrestal placement of this implant system appears to be advantageous in maintaining bone height coronal to the implant platform.