Hayder Habeeb JASIM, Rasheed Musleh IBRAHEM
Cumhuriyet Dental Journal - 2026;29(2):344-349
Objectives: To evaluate the effect of over-preparation of implant osteotomies on marginal bone loss and radiographic bone-loss patterns around implants placed bilaterally in the posterior mandible. Materials and Methods: A prospective bilateral clinical study was conducted in 30 partially edentulous adults. Each patient received at least two implants placed bilaterally in the posterior mandible, selected due to its intermediate bone density where both standard and over-preparation approaches may be clinically indicated. A total of 62 bone-level implants were placed: 31 with the manufacturer's standard osteotomy and 31 with an over-prepared osteotomy. Allocation was performed pragmatically based on intraoperative clinical judgement (including bone density and drilling resistance), rather than randomization, with over-preparation more frequently applied in denser bone to reduce excessive compression; this approach may introduce selection bias. Insertion torque and implant stability quotient were recorded at placement. The same operator performed all radiographs and prosthetic treatment. Standardised periapical radiographs were taken at prosthesis delivery, six months and twelve months. Marginal bone loss was measured from implant shoulder to first bone implant contact. Bone-loss patterns were classified as horizontal, vertical crater-like, circumferential, or combined vertical-buccal defects. Paired and mixed-effects analyses were applied to this dataset. Results: Over-prepared sites showed lower primary stability (insertion torque approximately 21 +/- 6 newton centimetres; implant stability quotient 61 +/- 5) than in standard sites (38 +/- 7 newton centimetres; 72 +/- 4). Mean marginal bone loss at six and twelve months was greater at over-prepared osteotomy sites (about 1.28 and 1.70 millimetres) than at standard sites (about 0.72 and 0.95 millimetres). Over-prepared sites showed a higher frequency of vertical crater-like, circumferential, and buccal dehiscence related bone loss patterns, whereas standard osteotomy sites predominantly exhibited horizontal remodelling or minimal change. Conclusions: Within the limitations of this non-randomised bilateral study model, over-preparation of osteotomies appears associated with reduced primary stability and increased, more vertical marginal bone loss at six and twelve months. Over-preparation should be avoided when possible, and alternative strategies considered when primary stability is at risk.
