Peri-implant tissue alteration around tissue-level and bone-level implants in fresh extraction sockets: a histomorphometric study in dogs

Abstract

Background: To compare tissue alteration in fresh extraction sockets between bone-level and tissue-level implants with different neck designs.Methods: Bilateral premolars of 6 adult Labrador dogs were extracted, and 24 bone-level and tissue level implants with two different neck designs were immediately placed. At the same time, buccal bony wall thickness in fresh extraction sockets was also recorded. The Straumann (R) Bone Level (BL) and Standard Plus (SP) implants were positioned at two insertion depths: 1mm below and flush with the alveolar crest. All animals were sacrificed 6 months after the implant placement. Undecalcified block sections were obtained for histological measurement. Vertical bone resorption and biological widths were documented. Statistical analysis consisted of two sample t-test and Wilcoxon sign-rank test.Results: All implants were histologically osseointegrated. There was no significant difference between BL implants and SP implants in vertical bone resorption regardless of the insertion depths (P 0.05). Meanwhile, significant difference was found in lingual biological width between BL (3.16 mm) and SP (2.43 mm) implants when placed 1mm below the alveolar crest (P<0.05). Conclusions: Within the limits, it seemed that different implant neck designs had little effect on bone remodeling in fresh extraction sockets. However, longer biological width was found in bone-level implants.