If there is recession present, how do you calculate CAL?

In the context of periodontal assessment, when evaluating clinical attachment loss (CAL), it's essential to understand how recession and probing depths influence the overall measurement of attachment. If recession is present, CAL is calculated by adding the amount of recession to the probing depth.

The rationale for this calculation is that clinical attachment loss reflects the total loss of periodontal support around a tooth, which includes both the loss caused by recession (which occurs when the gum tissue pulls away from the tooth) and the probing depth (which measures how deep the periodontal pocket is). By adding these two values together, you get a comprehensive view of the attachment level, which helps assess the severity of periodontal disease and plan appropriate treatment strategies.

In this case, other methodologies for calculating CAL would not provide the complete picture. For instance, simply subtracting probing depth from recession does not account for the overall attachment loss, which could lead to an inaccurate assessment. Dividing probing depth by two or using only the probing depth fails to integrate the critical contribution of recession to the overall clinical attachment level. Therefore, the method of adding recession to probing depth gives the most accurate measure of CAL in the presence of recession.