The association of early marginal bone loss relative to the implant restorative platform and pre-operative site-specific factors: retrospective cohort

AIM: To evaluate marginal bone loss (MBL) around dental implants measured at the 2nd stage surgery when placing the healing abutment and retrospectively to evaluate the association of several pre-surgical variables. MATERIAL AND METHODS: Eighty-seven patients with a total of 118 implants, were evaluated in this retrospective cohort. Age of patients varied between 23 to 80 years. Two implant systems were included: Nobel Biocare and Straumann Bone Level . Clinical measurements were recorded at four surfaces (mesial, distal, buccal, and lingual) vertically from the restorative platform to the adjacent crestal bone level immediately after the implant placement and again three months later at the 2nd stage abutment surgery. The change in marginal bone level (MBL) was recoded as the difference between these two measurements. Given the consensus view that it is “normal” to observe 1.0mm bone loss around the implant after placement, the measurements of bone change were divided into two categories: test and control. Test sites were defined as having MBL >1.0mm and the control sites were defined as having MBL <=1mm. Pre-surgical variables (age, sex, race, history of abscess, traumatic vs surgical extraction, socket preservation, site augmentation, healing times of grafts, and the healing time after implant placement) were identified from patients’ charts and evaluated using Chi-square test and t-test. RESULTS: For this cohort of 118 implant sites, mean MBL was 0.72 +/- 1.15 mm on the mesial, 0.58 +/- 1.0 mm on the distal, 0.66+/-1.49 mm on the buccal, and 0.57 +/- 0.98 on the lingual. The buccal MBL had a higher median of 1.00 mm, while the other locations had 0.5 mm. The comparisons showed statistically significant difference between test and control subjects for: 1.Buccal side on implants placed in areas that had a history of abscess compared to areas that never had infection before. 2.The buccal side on implants placed in areas with socket preservation compared to areas without socket preservation. 3.The mesial and distal sides on implants placed in areas that had longer healing intervals between graft placement and implant placement. CONCLUSION: This cohort of a retrospective study suggested that buccal sites of implants have more bone resorption at the second stage abutment surgery if implant sites have a history of abscess or if socket grafting was not done. Mesial and distal sites had less bone resorption if longer healing time was allowed between implant placement surgery and abutment surgery. Without a socket graft to provide physical scaffolding and maintain ridge volume, the naturally thin and poorly vascularized buccal wall is more vulnerable to post-extraction resorption. Reflecting a flap for treatment of an abscess adds further insult.

Author dc:creator

• Khodadah, Abdulwahab

Advisors dc:contributor.advisor

• Price, Albert M.
• Dibart, Serge

• Dentistry

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/2144/53239

OAI identifier oai:identifier

oai:open.bu.edu:2144/53239