Accuracy of Composite Attachment Position with Four Different Indirect Bonding Techniques

Introduction: Our objective was to evaluate the attachment transfer accuracy of four indirect bonding technique variations based on tray sectioning. Materials and Methods: Twenty 3D printed dental models without attachments were bonded with composite resin attachments using 0.5mm thermoform plastic template trays fabricated from physical reference models. Four IDB technique variations were studied, n=5 for each technique: 1) whole arch (Whole), 2) whole arch, buccal segment only (Halves), 3) sextants (Thirds), and 4) sextants, buccal segment only (Sixths). Dimensional deviation of attachment position was evaluated in the buccal-lingual (B/L), mesial-distal (M/D), incisal-gingival (I/G) dimensions, and in tip through model digitization and 3D software superimpositions with the reference digital model. Clinical significance cutoffs were set at 0.25mm for linear measurements and 1° for angular measurements. ANOVA and multiple comparisons were performed. Statistical significance was set at 0.05. Results: Across all techniques, a total of 142 attachments were evaluated. B/L- Left side attachments had more mean discrepancy than right side attachments, and there was a lingual bias of all attachments. M/D- The Thirds group had less deviation than all other techniques (p < 0.05). Across all attachments, there was virtually zero bias towards the mesial or distal. I/G- The Wholes and Sixths groups had the least and greatest deviation, respectively, and the difference was significant (p < 0.05). There was an incisal bias across all attachments. Tip- There was approximately a 1° distal root tip bias across all attachments. Overall, no mean linear deviations reached the clinical significance threshold, but mean angular deviations did. Conclusions: In general, all IDB techniques studied achieved clinically acceptable and similar attachment positions in the B/L, M/D, I/G, dimensions, and marginally acceptable tip angulation.