title: Histologic evaluation of guided vertical ridge augmentation around implants in humans.
abstract: Recent experimental and clinical case reports demonstrated vertical ridge regeneration in atrophic posterior mandibles and maxillae. Although the results from these clinical cases are quite encouraging there is a lack of human histologic data on the newly regenerated tissue around commercially available titanium implants. The aim of the present study was to perform a qualitative and quantitative histologic analysis of the bone response to previously exposed implant threads after treatment with guided bone regeneration in a series of patients. A total of 30 Nobel Biocare implants were consecutively placed in 6 patients with partially edentulous mandibles. Of these implants, 6 were planned for removal after 1 year, whereas the remaining 24 implants were inserted to function as support for a fixed partial denture. The 6 experimental implants were intentionally allowed to protrude occlusally 5 to 7 mm from the bone crest without counter-sinking. The exposed implant threads were completely covered by autogenous bone chips. After a 12-month healing period the 6 experimental implants were removed with trephine burs. Bone-to-metal contact and bone density in the implant threads were measured. Clinically, all implants were stable and there was complete tissue fill of the space underneath the membranes. Histologically, a substantial amount of new bone had formed underneath the membrane in all cases. Histomorphometrically, there was a lower bone-to-metal contact percentage in the exposed compared to the nonexposed region in every case. With respect to bone density, there was a mean of 43.2% in previously exposed regions compared to 60.3% in previously nonexposed regions.
authors.affiliation: Department of Periodontology, University of Ferrara Dental School, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Parma-Benfenati
authors.forename: C
authors.initials: C
authors.lastname: Tinti
authors.forename: T
authors.initials: T
authors.lastname: Albrektsson
authors.forename: C
authors.initials: C
authors.lastname: Johansson
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000601:surgery; D000539:Alveolar Process / Q000033:anatomy & histology*; D000540:Alveolar Ridge Augmentation; D001861:Bone Regeneration; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D005260:Female; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D016348:Osseointegration
chemical_list: D015921:Dental Implants; D008567:Membranes, Artificial