Finite Element Study of Biomechanical Behavior of Short Dental Implants with Bone Loss Effects – Evaluation of Bone Turnover

Contemporary dental implantology is, in essence, the outcome of advanced biomechanical engineering, particularly in addressing the challenge of inadequate bone quality and quantity in the posterior maxilla through the use of short implants. Their effectiveness depends on various factors, including the design, the quality of the patient’s bone, and the level of marginal bone loss. These factors ultimately influence how the functional load is transferred to the surrounding bone. The primary objective of our study was to assess the impact of the design and diameter of short plateau implants on the strain magnitudes experienced by the adjacent bone in cases where bone loss is a clinical concern. This evaluation aimed to provide insights into the prognosis of these implants, in terms of whether they contribute to healthy or pathological bone turnover. The study was focused on the assessment of the first principal strains (FPSs) within the contacting bone tissue to gauge the bone turnover surrounding three Bicon SHORT® implants with diameters of 4.5, 5.0, and 6.0 mm, and a length of 5.0 mm. These implants were tested across a range of bone loss levels, from 0.2 to 1.0 mm. 3D models of these implants were placed crestally in corresponding models of the posterior maxilla with type III bone characteristics and 1.0 mm thick crestal and sinus cortical bone layers. These models were subjected to a mean oblique load of 120.92 N, applied to the center of a 7. The analysis was focused on the maximal FPSs observed in the bone tissue. To evaluate the physiological or pathological bone turnover in adjacent area, we correlated maximal FPSs with a minimum effective strain threshold of 3000 μstrain (MESp) according to Frost. In cases of completely osseointegrated implants, the maximal FPSs ranged from 2000 to 3170 μstrain, were located in vicinity of the cortical/cancellous bone boundary, specifically at the first fin edge. In cases where bone loss was present, these maximal FPSs still occurred at the same location and were significantly influenced by the level of bone loss ((2120…3620, 2300…4180, 2500…4810, 2700…5520 and 2990…6400 μstrain for 0.2, 0.4, 0.6, 0.8 and 1.0 mm bone loss). The implant diameter played a substantial role in determining the maximal FPSs. Increasing the implant diameter from 4.5 to 6.0 mm resulted in a reduction in FPS by 41%, 45%, 48%, 51%, and 53% for bone loss levels of 0.2, 0.4, 0.6, 0.8, and 1.0 mm, respectively, in comparison to completely osseointegrated implants. N implant exhibited a significant increase of FPS at all studied levels of bone loss (14…102)%, rendering them unsuitable for type III bone due to FPS exceeding the 3000 μstrain threshold even for completely osseointegrated implants. W implant demonstrated (6…39)% of FPS increase but totally positive bone turnover across the range of bone loss levels, while M implant with (15…109)% of FPS increase only demonstrated this effect for bone loss up to 0.2 mm. These findings have important implications for implant manufacturers seeking to design more effective implants. Clinicians should also consider these results as valuable guidelines when working with short plateau implants in clinical practice.