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Straight and Angulated Abutments in Platform Switching: Influence of Loading on Bone Stress by Three-Dimensional Finite Element Analysis

Martini, Ana Paula DDS; MS*; Freitas, Amílcar Chagas Jr DDS; PhD; Rocha, Eduardo Passos DDS, PhD*; de Almeida, Erika Oliveira DDS, PhD§; Anchieta, Rodolfo Bruniera DDS, MS*; Kina, Sidney DDS, PhD; Fasolo, Guilherme Bortolon DDS, MS

Journal of Craniofacial Surgery: March 2012 - Volume 23 - Issue 2 - p 415–418
doi: 10.1097/SCS.0b013e31824b9c17
Original Articles

Purpose In view of reports in the literature on the benefits achieved with the use of platform switching, described as the use of an implant with a larger diameter than the abutment diameter, the goal being to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability and the need for implant inclination due to bone anatomy in some cases, the aim of this study was to evaluate bone stress distribution on peri-implant bone, by using three-dimensional finite element analysis to simulate the influence of implants with different abutment angulations (0 and 15 degrees) in platform switching.

Methods Four mathematical models of an implant-supported central incisor were created with varying abutment angulations: straight abutment (S1 and S2) and angulated abutment at 15 degrees (A1 and A2), submitted to 2 loading conditions (100 N): S1 and A1—oblique loading (45 degrees) and S2 and A2—axial loading, parallel to the long axis of the implant. Maximum (σmax) and minimum (σmin) principal stress values were obtained for cortical and trabecular bone.

Results Models S1 and A1 showed higher σmax in cortical and trabecular bone when compared with S2 and A2. The highest σmax values (in MPa) in the cortical bone were found in S1 (28.5), followed by A1 (25.7), S2 (11.6), and A2 (5.15). For the trabecular bone, the highest σmax values were found in S1 (7.53), followed by A1 (2.87), S2 (2.85), and A2 (1.47).

Conclusions Implants with straight abutments generated the highest stress values in bone. In addition, this effect was potentiated when the load was applied obliquely.

From the *Department of Dental Materials and Prosthodontics, Araçatuba School of Dentistry, †Department of Post-Graduation, School of Health Sciences, UnP; §Department of Dentistry, UFRN; and ‡Post-Graduate Center, São Leopoldo Mandic School, Campinas, SP, Brazil.

Received October 7, 2010.

Accepted for publication April 2, 2011.

Address correspondence and reprint requests to Eduardo Passos Rocha, DDS, PhD, Departamento de Materiais Odontológicos e Prótese, R. José Bonifácio, 1193, Araçatuba, São Paulo, Brazil, CEP: 16015-050; E-mail:

This study was supported by the São Paulo Research Foundation (FAPESP–Brazil, no. 2008/00209-9).

The authors report no conflicts of interest.

© 2012 Mutaz B. Habal, MD