A method for adjusting caries increments for reversals due to examiner misclassification

Area of Science:

• Dental research
• Epidemiology
• Biostatistics

Background:

• Longitudinal caries studies traditionally use Net Caries Increment (NCI) by subtracting examiner reversals from Crude Caries Increment (CCI).
• NCI assumes equal false positive and false negative errors, which may not hold true, especially at lower diagnostic thresholds.
• This assumption can lead to an underestimation of true caries incidence.

Purpose of the Study:

• To develop and validate a novel formula for calculating caries increment that accounts for examiner misclassification errors.
• To compare the performance of the Adjusted Caries Increment (ADJCI) with Crude Caries Increment (CCI) and Net Caries Increment (NCI).
• To assess the impact of different increment calculation methods on detecting intergroup differences in caries progression.

Main Methods:

• A new formula, ADJCI = y2(1-(y3/(y3 + y4))), was created to adjust for reversals based on prevalence.
• Data from 452 older Black and White adults followed over a 3-year period were used for illustration.
• The formula defines y2 as 'sound to decayed/filled', y3 as 'decayed/filled to sound', and y4 as 'decayed to decayed/filled or filled to filled'.

Main Results:

• The ADJCI method resulted in higher caries increments compared to the NCI.
• Significant Black-White differences in caries progression were observed with CCI and ADJCI, but not with NCI.
• For example, 3-year coronal DS increment was 0.62 (CCI), 0.26 (NCI), and 0.56 (ADJCI) for whites.

Conclusions:

• The NCI may be too conservative an adjustment for reversals in certain populations.
• The ADJCI offers a more sensitive approach for detecting caries increment and intergroup differences in clinical trials.
• Adjusting for examiner reversals using a prevalence-based method like ADJCI is crucial for accurate caries assessment.