Histologic and histomorphometric evaluation of minicono abutment on implant surrounding tissue healing and bone resorption on implants placed in healed bone. An experimental study in dogs

Abstract

<abstract> <p>The objective of this evaluation was to measure the width and length of connective tissue (CT) and crestal bone resorption (CBR) related to minicono® abutment inserted in conical connection dental implants, which were placed crestal and subcrestally in a dog's mandible.</p> <sec> <title>Materials and Methods</title> <p>Forty-eight Top DM implants with the same coronal diameter were placed at the crestal level, 1 mm (test 1 group) and 2 mm (test 2 group) positions underneath buccal-lingual bone crests. Dental implants used in the study were separated into three groups of 16 implants each. The implants were randomly inserted into healed bone after two months post-extraction sockets of three lower premolars, and first molar, bilaterally in six male fox hound dogs. One 3 mm minicono height abutment was connected to conical connection implants placed at the crestal level (control), 1 mm (test 1) and 2 mm (test 2) positions under buccal-lingual crests.</p> </sec><sec> <title>Results</title> <p>All abutments and implants used were clinically and histologically integrated into the bone-soft tissue. Soft tissue behavior was observed at eight and 12 weeks in all test groups, displaying similar quantitative findings with significant differences (p > 0.05). However, crestal bone loss was significantly greater at the buccal side around that control group compared to the test 1 and 2 groups. The difference values between groups at the implant shoulder to the top of the lingual bone crest (IS-LBC) and the implant shoulder to the top of the buccal bone crest (IS-BBC) were significantly greater for the test 2 group in comparison with the other two groups (p < 0.05) at eight weeks. In addition, crestal bone resorption (CBR) increased in the crestal group at twelve weeks, but it was reduced for the test 1 and test 2 groups in implants placed sub-crestally (p < 0.05).</p> </sec><sec> <title>Conclusions</title> <p>Crestal bone loss could be reduced using a 3 mm high abutment on implants submerged below the bone crest from 1 to 2 mm positions.</p> </sec></abstract>