IADR Abstract Archives
Accuracy and Reliability of EMA AG501 for Mandibular Movement Analysis
Objectives: The aim of this study is to assess the reliability of 3D Electromagnetic Articulograph (EMA) AG501 in order to validate its use for 3D mandibular movement analysis in dentistry.
Methods: Two tests were conducted, in which 16 sensors were attached to a rotating rigid structure placed inside the measurement area. Three additional tests were conducted to evaluate the performance of the AG501 in mandibular movement analysis, in which a mouth anatomical model with human-like articulatory behavior was employed. EMA raw data were normalized applying a function of the EMA system. All data registered with the EMA, raw and normalized, were processed using custom-developed Matlab scripts in order to obtain intelligible data representation and statistical results. A Bland Altman analysis of agreement between EMA and the millimeter ruler was implemented to evaluate reliability.
Results: Raw data spatial representation showed an unexpected shift at the upper section of the measurement area more intense for static tests than for dynamic tests. The system accuracy was higher at the center of the measurement area and decreased towards the edges. Position SD fluctuated between 0.001 mm and 0.185 mm. Dispersion was always greater for raw data than for normalized data. Bland Altman analysis of agreement between the AG501 and a millimeter ruler revealed limits of agreement between 0.5 mm and -0.9 mm. Distance-measurement SD for the sensors located on the mouth anatomical model fluctuated between 0.02 mm and 0.58 mm.
Conclusions: Results showed that 3D Electromagnetic Articulograph AG501 is an accurate and reliable tool to analyze mandibular movements. Nonetheless, systematic errors were observed in our study as in previous studies. Therefore, we suggest that each research group test their equipment to avoid measurements in conflictive areas.
Methods: Two tests were conducted, in which 16 sensors were attached to a rotating rigid structure placed inside the measurement area. Three additional tests were conducted to evaluate the performance of the AG501 in mandibular movement analysis, in which a mouth anatomical model with human-like articulatory behavior was employed. EMA raw data were normalized applying a function of the EMA system. All data registered with the EMA, raw and normalized, were processed using custom-developed Matlab scripts in order to obtain intelligible data representation and statistical results. A Bland Altman analysis of agreement between EMA and the millimeter ruler was implemented to evaluate reliability.
Results: Raw data spatial representation showed an unexpected shift at the upper section of the measurement area more intense for static tests than for dynamic tests. The system accuracy was higher at the center of the measurement area and decreased towards the edges. Position SD fluctuated between 0.001 mm and 0.185 mm. Dispersion was always greater for raw data than for normalized data. Bland Altman analysis of agreement between the AG501 and a millimeter ruler revealed limits of agreement between 0.5 mm and -0.9 mm. Distance-measurement SD for the sensors located on the mouth anatomical model fluctuated between 0.02 mm and 0.58 mm.
Conclusions: Results showed that 3D Electromagnetic Articulograph AG501 is an accurate and reliable tool to analyze mandibular movements. Nonetheless, systematic errors were observed in our study as in previous studies. Therefore, we suggest that each research group test their equipment to avoid measurements in conflictive areas.