IADR Abstract Archives
Determining The Accuracy Of CBCT For Measuring Enamel And Dentine.
Objectives:
To determine the accuracy and reliability of using Cone Beam Computed Tomography (CBCT) measuring software to make linear measurements of enamel and dentine by comparing its linear measurements of tooth sections with those measured with digital callipers. In this manner preoperative measurements of dentine could be determined to prevent over-preparation of teeth.
Methods: Sixteen extracted permanent teeth were sectioned, embedded in a typodont model and a CBCT image acquired. From 21 tooth sections, 14 aspects were measured. Measurements of enamel and dentine widths were made with digital callipers independently by two evaluators, and repeated with CBCT software. Intra-Class Correlations were used to determine the inter-rater correlations. The Bland-Altman test compared the two techniques to determine their limits of agreement and clinical relevance.
Results: Both methods were found to be reliable (r=0.999). CBCT measurements were slightly higher than calliper measurements in about 60 percent of all measurements. The Bland-Altman analysis determined the limits of agreement to range between -0.04mm and -0.140mm, with 95% of the values residing within this range.
Conclusions: The margin of error between the two types of measurements translates to between 4 and 140µm of tooth dentine or enamel thickness. As this is less than the 500 µm minimum width of residual dentine at which histological changes in the dentino-pulpal complex can be observed after preparation, the two methods can be used interchangeably to measure tooth dimensions of enamel and dentine.
To determine the accuracy and reliability of using Cone Beam Computed Tomography (CBCT) measuring software to make linear measurements of enamel and dentine by comparing its linear measurements of tooth sections with those measured with digital callipers. In this manner preoperative measurements of dentine could be determined to prevent over-preparation of teeth.
Methods: Sixteen extracted permanent teeth were sectioned, embedded in a typodont model and a CBCT image acquired. From 21 tooth sections, 14 aspects were measured. Measurements of enamel and dentine widths were made with digital callipers independently by two evaluators, and repeated with CBCT software. Intra-Class Correlations were used to determine the inter-rater correlations. The Bland-Altman test compared the two techniques to determine their limits of agreement and clinical relevance.
Results: Both methods were found to be reliable (r=0.999). CBCT measurements were slightly higher than calliper measurements in about 60 percent of all measurements. The Bland-Altman analysis determined the limits of agreement to range between -0.04mm and -0.140mm, with 95% of the values residing within this range.
Conclusions: The margin of error between the two types of measurements translates to between 4 and 140µm of tooth dentine or enamel thickness. As this is less than the 500 µm minimum width of residual dentine at which histological changes in the dentino-pulpal complex can be observed after preparation, the two methods can be used interchangeably to measure tooth dimensions of enamel and dentine.