Effects of tensile and compressive stress on bone resorption and formation parameters surrounding dental implants

This study investigates the effects of tensile and compressive stresses on peri-implant bone remodeling activity. Titanium implants were inserted into the extracted maxillary molar sites of four-week-old male mice and allowed to heal. A sustained load of 0.9 N, inclined at 30° from palatal to buccal, was applied for 30 min daily over 7 days. Non-loaded implants served as a controls. Non-demineralized sections parallel to the occlusal plane were prepared 150 μm below the alveolar crest, and bone morphometry parameters related to bone resorption and formation were measured within a 120 μm-wide peri-implant region, divided into distal, buccal, mesial, and palatal quarters. Stress distribution was calculated using an animal-specific three-dimensional (3D) finite element (FE) model based on microfocus CT data. In the buccal quarter, where compressive stress was statistically higher than in the other quarters, and the mesial quarter, where tensile stress was greater than that in the other quarters, bone remodeling parameters increased significantly upon loading (p < 0.05), aligning with previous in vivo findings that mechanical stress influences bone-related cell activity. However, no significant parameter changes were observed in the distal quarter, where both tensile and compressive stresses were higher than those in the other quarters. This suggested regional suppression of remodeling activity by a simultaneous concentration of tension and compression. These findings offer crucial insights into the preservation and maintenance of the peri-implant bone under mechanical stress from occlusal forces, highlighting the role of stress distribution in bone remodeling.