Fig. 1

Superimposition and measurement of the models. A The target tooth without attachments was segmented from the whole dentition model (T0). B The target tooth with attachments was segmented from the whole dentition model (T1/T2/T3/T4/T5). C Tooth surfaces without resin were selected (T1/T2/T3/T4/T5). D A Boolean calculation was performed after the T0 (gray) and the T1/T2/T3/T4/T5 (blue) segmented models were superimposed based on the tooth surface without resin using the best-fit algorithm. The attachment area was selected to obtain the attachment volume at different follow-up times. E A 3D deviation analysis was performed after the T1 and T2/T3/T4/T5 segmented models were superimposed according to the above method. The segmented T1 model was set as a reference. The attachment area was selected to determine the average wear depth and wear area. The color map shows the morphological differences. The green color represents no differences. The yellow color represents the surface of the reference model (T1) on the inner side, which probably indicates the existence of plaque. The blue color represents the surface of the reference model (T1) on the outer side, which indicates that wear has occurred. The extent of wear is proportional to the darkness of the blue