Histomorphological alterations in human bone tissue following in vivo osteotomy: a comparative study of conventional drilling, piezosurgery, and er: YAG laser ablation.

objectivesThis study aimed to evaluate, compare, and map the specific zones of histomorphological and tissue alterations in human bone following in vivo osteotomy performed by conventional drilling, piezosurgery, and Er: YAG laser ablation, proposing a universal zonal model of bone tissue response. MATERIALS AND

methodsA total of 80 human mandibular bone samples obtained during in vivo third molar extractions requiring bone removal were evaluated. The specimens were divided into three experimental groups based on the active osteotome used: conventional drilling (n = 20), piezosurgery (n = 30), and Er: YAG laser ablation (n = 30). Histological and histomorphometric screenings (Toluidine blue staining, magnifications х 10, х 20, and х 40), and scanning electron microscopy (magnification х 2500) were performed to identify, measure, and compare the zones of structural, mechanical, and collateral thermal alterations adjacent to the cutting edges.

resultsDistinct microstructural tissue modification patterns were identified, with significant dependence on the physical cutting mechanism (p < 0.05). Conventional drilling produced an irregular configuration with an attached "smear-like" debris layer (142.0 ± 45.31 μm) and the most extensive collateral thermal necrosis zone (168.05 ± 56.42 μm). Piezosurgery produced a heavily fragmented, irregular cutting line accompanied by a loose peripheral "satellite halo" of micronized fragments (206.73 ± 107.42 μm) but yielded the narrowest thermal damage zone (49.03 ± 39.91 μm). Conversely, Er: YAG ablation produced 100% sharp, regular, and clean borders without debris or micro-fragment layers, demonstrating a well-demarcated photothermal modification zone (99.50 ± 67.63 μm). Cross-modality evaluation showed that the choice of device significantly determined both surface debris architecture (F = 68.361, p = 0.001) and thermal alteration depth (F = 27.374, p = 0.001).

conclusionsDifferent bone-cutting instruments induce distinct, predictable zones of structural and morphological alterations in vital human bone, validating a three-layered universal zonal model (Surface Interface, Transitional Reactive, and Unaltered Native Matrix). Both Er: YAG laser and piezosurgery exhibit superior atraumatic characteristics and advanced tissue-preservation capabilities in humans compared to conventional drilling, providing a powerful biological rationale for their expanded clinical implementation in bone surgery.