Measurement and comparison of bracket transfer accuracy of five indirect bonding techniques

Abstract

Objective: To measure and compare bracket transfer accuracy of five indirect bonding (IDB) techniques.

Materials and methods: Five IDB techniques were studied: double polyvinyl siloxane (double-PVS), double vacuum-form (double-VF), polyvinyl siloxane vacuum-form (PVS-VF), polyvinyl siloxane putty (PVS-putty), and single vacuum-form (single-VF). Brackets were bonded on 25 identical stone working models. IDB trays were fabricated over working models (n = 5 per technique) to transfer brackets to another 25 identical stone patient models. The mesiodistal (M-D), occlusogingival (O-G), and faciolingual (F-L) positions of each bracket were measured on the working and patient models using digital photography (M-D, O-G) and calipers (F-L). Paired t-tests were used to compare bracket positions between working and patient models, and analysis of variance was used to compare bracket transfer accuracy among the five techniques.

Results: Between the working and patient models, double-VF had the most teeth with significant differences (n = 6) and PVS-VF the fewest (n = 1; P < .05). With one exception, all significant differences were ≤0.26 mm and most (65%) were ≤0.13 mm. When the techniques were compared, bracket transfer accuracy was similar for double-PVS, PVS-putty, and PVS-VF, whereas double-VF and single-VF showed significantly less accuracy in the O-G direction.

Conclusions: Although overall differences in bracket position were relatively small, silicone-based trays had consistently high accuracy in transferring brackets, whereas methods that exclusively used vacuum-formed trays were less consistent.

Keywords: Bracket bonding accuracy; Indirect bonding.

Figures

Figure 1.

Maxillary typodont with reference notches on facial and lingual surfaces.

Figure 2.

A jig with fixed positioning blocks was used to establish repeatable locations of the camera, ruler, and models.

Figure 3.

Measurement points for molars and nonmolars, with constructed origin and grid. Points A and B were used for photography, and points C and D were used for caliper measurements.

Figure 4.

Digital caliper measuring F-L bracket position, with nonmobile end of caliper placed at the depth of the lingual reference notch and mobile end on points C and D (see Figure 3).

Figure 5.

Comparison of mean differences in bracket position among the five techniques for all teeth grouped. * P

Figure 6.

Comparison of mean differences in bracket position among the five techniques for anterior teeth. * P

Figure 7.

Comparison of mean differences in bracket position among the five techniques for posterior teeth. * P

Figure 8.

Comparison of mean differences in bracket position among the five techniques for left and right sides of the arch. * P