Mechanical Stress Analysis of Different Configurations of the All-on-4 Concept in Atrophic Mandible: A 3D Finite Element Study (original) (raw)

The International Journal of Oral & Maxillofacial Implants

T ooth loss is a common problem, not strictly, but highly prevalent, in the elderly population. 1,2 In general, long-term edentulous patients exhibit excessive alveolar bone resorption, which sometimes restricts the placement of dental implants, especially in the posterior area of the mandible. 3 It is noteworthy that such restrictions affect the definitive prosthesis design 4 and may result in long prosthetic cantilevers, 5 which are associated with higher amounts of stress transmitted to the prosthetic bar, prosthetic screws, abutments, and peri-implant bone. 6 The All-on-4 treatment concept (Nobel Biocare) introduced by Maló et al 7 enables the rehabilitation of severely resorbed arches with a complete fixed prosthesis connected to four dental implants. The rationale behind this concept is that by distally tilting the posterior implants at 30 or 45 degrees, bone-to-implant contact can be improved, reductions in the cantilever length can be achieved, and the oral rehabilitation can be performed with a minimum risk of causing injury in the inferior alveolar nerve. 8 Nevertheless, the presence of a minimum bone volume is of utmost importance to perform the All-on-4 treatment with dental implants of "sufficient" length (at least 10.0 mm). 7,8 Otherwise, complementary surgical procedures for vertical bone augmentation are priorly indicated. 9,10