Monocortical versus bicortical hard palate anchorage with the same total available cortical thickness: a finite element study.

Objective: We aimed to compare the bicortical fixation of a palatal miniscrew in comparison to monocortical anchorage when total anchored cortical layer thicknesses are the same.

Materials And Methods: Six models were designed: I, monocortical, 1.1 mm palatal cortical thickness, 8.5 mm bone height; II, bicortical, 0.4 mm palatal, 0.7 mm nasal cortical thickness, 8 mm bone height; III, bicortical, 0.7 mm palatal and 0.4 mm nasal cortical thickness, 8 mm bone height; IV, monocortical, 1.1 mm palatal cortical thickness, 7 mm bone height; V, bicortical, 0.4 mm palatal, 0.7 mm nasal cortical thickness, 7 mm bone height; VI, bicortical, 0.7 mm palatal and 0.4 mm nasal cortical thickness, 8.5 mm bone height. An 8 mm miniscrew was fully engaged in the bone and was subjected to vertical pull out until displaced 0.01 mm and 0.05 mm or horizontal traction load of 2 N.

Results: Monocortical fixation provides higher retention in comparison to bicortical fixations with the same total cortical thicknesses in terms of vertical pull-out test. Models with bicortical fixation and thicker nasal cortex sustained lower strain energy when subjected to horizontal traction load.

Conclusion: Bicortical fixation of hard palate exhibit different reactions to vertical and horizontal tractions.