Osseointegration in periodontitis susceptible individuals

OBJECTIVES: The aim of the present study was to examine tissue integration of implants placed (i) in subjects who had lost teeth because of advanced periodontal disease or for other reasons, (ii) in the posterior maxilla exhibiting varying amounts of mineralized bone. MATERIAL AND METHODS: Thirty-six subjects were enrolled; 19 had lost teeth because of advanced periodontitis (group P) while the remaining 17 subjects had suffered tooth loss from other reasons (group NP). As part of site preparation for implant placement, a 3 mm trephine drill was used to remove one or more 2 mm wide and 5-6 mm long block of hard tissue [biopsy site; Lindhe et al. (2011). Clinical of Oral Implants Research, DOI: 10.1111/j.1600-0501.2011.02205.x]. Lateral to the biopsy site a twist drill (diameter 2 mm) was used to prepare the hard tissue in the posterior maxilla for the placement of a screw-shaped, self-tapping micro-implant (implant site). The implants used were 5 mm long, had a diameter of 2.2 mm. After 3 months of healing, the micro-implants with surrounding hard tissue cores were retrieved using a trephine drill. The tissue was processed for ground sectioning. The blocks were cut parallel to the long axis of the implant and reduced to a thickness of about 20 μm and stained in toluidine blue. The percentage of (i) implant surface that was in contact with mineralized bone as well as (ii) the amount of bone present within the threads of the micro-implants (percentage bone area) was determined. RESULTS: Healing including hard tissue formation around implants placed in the posterior maxilla was similar in periodontitis susceptible and non-susceptible subjects. Thus, the degree of bone-to-implant contact (about 59%) as well as the amount of mineralized bone within threads of the micro-implant (about 45-50%) was similar in the two groups of subjects. Pearson's coefficient disclosed that there was a weak negative correlation (-0.49; P < 0.05) between volume of fibrous tissue (biopsy sites) and the length of bone to implant contact (BIC) while there was a weak positive correlation (0.51; P < 0.05) between the volume of bone marrow and BIC.