Fracture Resistance of Internal Conical and External Hexagon: Regular and Narrow Implant-Abutment Assemblies.
OBJECTIVE
The aim of this study was to compare the maximum load on the elastic limit of internal conical (IC) implants with regular external hexagon (REH) and narrow external hexagon (NEH) implants.


METHODS
Thirty cylindrical implants were divided in 3 groups (n = 10): REH (3.75 mm); NEH (3.3 mm); IC (3.5 mm). The implants were evaluated by means of cantilever bending loads using a mechanical testing machine. A strain qualitative analysis and the corresponding angles were analyzed. Using single factor analysis of variance with Tukey Test and Friedman Test (P < 0.05) the statistical analysis for data were performed.


RESULTS
REH (294.37 N) and IC (294.37 N) groups presented statistically greater Fle than NEH (189.16 N). Regarding to the strain, there were no significant differences among groups. However, there were a greater number of fissures and more fractures present on NEH group.


CONCLUSIONS
The IC implant with smaller diameter did not result in reduction of elastic limit when compared with the REH implants. Nevertheless, the reduction of 0.45 mm of the hexagonal connection implant's diameter has significantly diminished the elastic limit.
*PhD Student, Department of Occlusion, Fixed Prostheses, and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil. †Professor, Department of Prosthodontics, School of Dentistry, Patos de Minas, Brazil. ‡Professor, Department of Prosthodontics, School of Dentistry, Federal University of Rio Grande do Norte, Natal, Brazil. §Adjunct Professor, Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil. ¶Adjunct Professor, Department of Mechanical Projects, School of Mechanical Engineering, Federal University of Uberlândia, Uberlândia, Brazil. ‖Associate Professor, Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil.
Thiago de Almeida Prado Naves
Tde A
Carneiro
Lia
L
Dietrich
Marcel Santana
MS
Prudente
João Paulo
JP
da Silva Neto
Célio Jesus
CJ
do Prado
Cleudmar Amaral
CA
De Araújo
Flávio Domingues
FD
das Neves
D000044:Dental Abutments / Q000009:adverse effects; D059605:Dental Implant-Abutment Design / Q000009:adverse effects*; D003758:Dental Implantation, Endosseous / Q000009:adverse effects* / Q000379:methods; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods; D004548:Elasticity; D006801:Humans; D016474:Weight-Bearing