Evaluation of bending strength of five interdental fixation apparatuses applied to canine mandibles.

Strength in bending was determined for interdental fixation apparatuses applied to hemimandibles obtained from 24 canine cadavers. Hemimandibles were osteotomized perpendicular to the long axis between the third and fourth premolars, and segments were stabilized with 1 of 5 interdental fixation apparatuses: Erich arch bar (EAB, n = 6); Stout loop (SL, n = 6); acrylic (A, n = 6); Stout loop and acrylic (SLA, n = 24); and Erich arch bar and acrylic (EABA, n = 6). Ultimate strengths (mean +/- SEM) of EAB, SL, A, SLA, and EABA were 395 +/- 48; 523 +/- 57; 1,106 +/- 102; 1,306 +/- 156; and 2,707 +/- 504 N.m, respectively. Stiffness (mean +/- SEM) of EAB, SL, A, SLA, and EABA were 2,944 +/- 357; 6,322 +/- 2,201; 16,010 +/- 5,017; 15,777 +/- 1,026; and 27,079 +/- 5,576 N.m/radian, respectively. Yield strengths (mean +/- SEM) of EAB, SL, A, SLA, and EABA were 66 +/- 6; 264 +/- 19; 911 +/- 126; 1,114 +/- 159; and 1,855 +/- 401 N.m, respectively. There were no significant differences in acrylic weight, cross-sectional area of the acrylic, or area moment of inertia of acrylic at the osteotomy site among A, SLA, and EABA; and there were no significant differences in osteotomy surface area and area moment of inertia at the osteotomy site among all apparatuses (P > 0.05). The EABA apparatus had significantly higher mean ultimate strength, mean stiffness, and mean yield strength compared to other interdental fixation apparatuses. There were no significant differences in the mean ultimate strength, mean stiffness, or mean yield strength between EAB and SL (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)