IADR Abstract Archives
Third Molar Maturity Index to Determine 18-Year-old for Thai Population
Objectives: The aim of this study was to determine the specific cut-off point in a Thai population to indicate that an individual was 18-years-old using the third molar maturity index previously reported.
Methods: 1000 digital panoramic radiographs were retrospectively evaluated from the hospital database at the Radiology clinic, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. The samples were Thai, age 15-24 years old. The samples were categorized into 10 age groups. The width of the root apices and tooth length of the mandibular third molars were measured and the third molar maturity index (I3M) was calculated based on previously published method. The evaluations were performed by two observers. Twenty percent of the samples were randomly selected for repeated measurements after 4 weeks. Statistical analysis was performed.
Results: The new specific cut-off value of (I3M) in this Thai population was 0.1255. The sensitivity and specificity was 84.3% and 78.3%, respectively. The Youden index was 0.626, which was closer to 1 than the cut-off value previously reported (0.595) when applied to this Thai population. The probabilities of correctly classifying individuals were 89.7% in males and 87.0% females. Intraclass correlation coefficients showed excellent intra-observer (0.993) and inter-observer reliability (0.991).
Conclusions: This study found a new cut-off point of I3M specific for a Thai population. If the calculated I3M of an individual is <0.1255, there is a high probability that the person is 18 years old or older. The application of this new finding will be useful for identifying minors among illegal laborers and migrants in Thailand.
Methods: 1000 digital panoramic radiographs were retrospectively evaluated from the hospital database at the Radiology clinic, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand. The samples were Thai, age 15-24 years old. The samples were categorized into 10 age groups. The width of the root apices and tooth length of the mandibular third molars were measured and the third molar maturity index (I3M) was calculated based on previously published method. The evaluations were performed by two observers. Twenty percent of the samples were randomly selected for repeated measurements after 4 weeks. Statistical analysis was performed.
Results: The new specific cut-off value of (I3M) in this Thai population was 0.1255. The sensitivity and specificity was 84.3% and 78.3%, respectively. The Youden index was 0.626, which was closer to 1 than the cut-off value previously reported (0.595) when applied to this Thai population. The probabilities of correctly classifying individuals were 89.7% in males and 87.0% females. Intraclass correlation coefficients showed excellent intra-observer (0.993) and inter-observer reliability (0.991).
Conclusions: This study found a new cut-off point of I3M specific for a Thai population. If the calculated I3M of an individual is <0.1255, there is a high probability that the person is 18 years old or older. The application of this new finding will be useful for identifying minors among illegal laborers and migrants in Thailand.