Correlation of M-L, Leinfelder, and USPHS clinical evaluation techniques for wear

Most recent clinical research studies on wear of posterior composite restorations have used the USPHS and Leinfelder measuring techniques. New studies are adopting the Moffa-Lugassy (M-L) technique. However, to date there has been no means of comparing results of the different techniques. The objective of this study was to correlate the M-L scale wear values to Leinfelder scale wear values and to USPHS scale alfa-bravo transitions, so that data can be pooled across studies for comparisons. M-L evaluations were made for 221 restorations previously evaluated by the USPHS and Leinfelder methods. The M-L wear values were determined as the mean of three independent evaluators' values. At the USPHS alfa-bravo transition, the mean Leinfelder wear value was 192 microns, and the mean M-L value was 97 microns. The correlation coefficient for the linear regression of M-L values vs. Leinfelder values was 0.87. The scales were linearly related, with a slope of 0.52. The average values for M-L readings of wear were statistically different and approximately half the Leinfelder values.