Aim: Bendable and angulated single-piece implants are used alternatively to screwable abutments in two-piecedental implant designs. Though used frequently, data on the stress distribution within such implants are not availableand the question whether the bending contributes to fracture resistance has not been addressed. Methods: We used the method of fi nite element to identify von Mises stresses and maximum stresses in bent andnon-bent but angulated implants. Implants with one (e.g. applicable to screw designs) or two (applicable to basalimplants) bending areas were the variables under investigation. Results: For bends up to 13 degrees we discovered that if there is only one bend, the maximum stress is in the bentarea. If two bends are made in two diff erent bending areas, the maximum stresses are distributed between the twoand, if either one of the bent areas is machined, there are no residual stresses within the implant body in this area.The maximum stresses are always located near the base-plates. The absolute value of the maximum stress is higherbecause no residual stresses are available to compensate stresses that stem from loading.Conclusion: Assuming that all other parameters are equal, bendable (basal) implants show a more even stress distributionalong the vertical implant region than identically shaped implants with a machine-angulated area. Bendablebasal implants therefore probably resist masticatory forces better than pre-angulated, machined implants, and unbentimplants which provide a thin region in the vertical implant area.

Czech Technical University Prague Laboratory of Biomechanics Department of Mechanics Biomechanics and Mechatronics Faculty of Mechanical Engineering Prague

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