Mechanical evaluation of newly designed miniplates for orthodontic skeletal anchorage

Aluno: Rocío Altagracia Romero Valdez
Orientador(a): Dr. Roberto Hideo Shimizu
Área: Ortodontia
Ano: 2016

The purpose of this study was to conduct a mechanical evaluation on miniplates
newly designed to assure itsclinical applicability in orthodontics. The sample consisted of
six 6 of each miniplate design: straight, Y and T (n=18) of 23mm length manufactured in
pure titanium grade 2. A three (3) point bend test was performed to validate mechanical
yield strength. The test was executed at the NeoOrtho® laboratories (Curitiba, Brazil.). An
Instron® fatigue testing system, model 8872, delivered the bending forces. The miniplates
were placed flatwise in the testing machine at a support distance of 12.35mm and the test
rate was of 5mm/min. The test recorded the values obtained for: yield load, yield
displacement, stiffness and bending moments for each miniplate. Statistical analysis
included de application of test of normality by Kolomogorov-Smirnov, homogeneity test
by ANOVA, multiple comparison tests of Tukey HSD and Games-Howell for homogenous
and heterogeneous variances respectively. The Pearsons coefficient determined
correlations between the variables. The straight miniplate presented a statistically
significant difference of greater stiffness and lees displacement when it was compared to
the Y and T miniplates.There is a very strong positive correlation between yield load, yield
displacement and bending moment. On the other hand, there is a strong negative
correlation between stiffness and yield displacement. All miniplates designs tested
demonstrated adequate mechanical properties that withstand orthodontic and orthopedic