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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 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 5 6) and PVS-VF the fewest (n 5 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. (Angle Orthod. 2014;84:607-614.)

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The BAG-Bonds showed the capacity for buffering acidic oral environments and significant release of calcium ions into their surrounding environment, and they hold the potential to be biomimetic bonding agents that may reduce white spot lesion formation.

Structured Abstract Objectives To investigate the accuracy and reliability of cone beam computed tomography (CBCT) measurements of buccal alveolar bone height (BBH) and thickness (BBT) using custom acquisition settings. Settings and Sample Population School of Dentistry, Oregon Health & Science University. Twelve embalmed cadavers. Materials and Methods Cadaver heads were imaged by CBCT (i‐CAT® 17–19, Imaging Sciences International, Hatfield, PA) using a ‘long scan’ (LS) setting with 619 projection images, 360° revolution, 26.9 s duration, and 0.2 mm voxel size, and using a ‘short scan’ (SS) setting with 169 projection images, 180° rotation, 4.8 s duration, and 0.3 mm voxel size. BBH and BBT were measured with 65 teeth, indirectly from CBCT images and directly through dissection. Comparisons were assessed using paired t‐tests (p ≤ 0.05). Level of agreement was assessed by concordance correlation coefficients, Pearson's correlation coefficients, and Bland–Altman plots. Results Mean differences in measurements compared to direct measurements were as follows, LS 0.17 ± 0.12 (BBH) and 0.10 ± 0.07 mm (BBT), and SS 0.41 ± 0.32 (BBH) and 0.12 ± 0.11 mm (BBT). No statistical differences were found with any of BBH or BBT measurements. Correlation coefficients and Bland–Altman plots showed agreement was high between direct and indirect measurement methods, although agreement was stronger for measurements of BBH than BBT. Conclusions Compared to the LS, the similarity in results with the reduced scan times and hence reduced effective radiation dose, favors use of shorter scans, unless other purposes for higher resolution imaging can be defined.

Objective: To compare changes in enamel microhardness adjacent to orthodontic brackets after using bonding agents containing various compositions of bioactive glass compared to a traditional resin adhesive following a simulated caries challenge. Materials and Methods: Extracted human third molars (n 5 10 per group) had orthodontic brackets bonded using one of four novel bioactive glass (BAG)-containing orthodontic bonding agents (BAG-Bonds) or commercially available Transbond-XT. The four new adhesives contained BAG in varying percentages incorporated into a traditional resin monomer mixture. Teeth were cycled through low-pH demineralizing and physiologic-pH remineralizing solutions once each day over 14 days. Microhardness was measured on longitudinal sections of the teeth 100, 200, and 300 mm from the bracket edge and beneath the brackets, at depths of 25 to 200 mm from the enamel surface. Normalized hardness values were compared using three-way analysis of variance. Results: Significantly less reduction in enamel microhardness was found with the experimental adhesives at depths of 25 and 50 mm at all distances from the bracket edge. In all groups, there were no significant changes in enamel microhardness past 125-mm depth. Results varied with the different BAG-Bonds, with 81BAG-Bond showing the smallest decrease in enamel microhardness. Conclusions: The BAG-Bonds tested in this study showed a reduction in the amount of superficial enamel softening surrounding orthodontic brackets compared to a traditional bonding agent. The results indicate that clinically, BAG-Bonds may aid in maintaining enamel surface hardness, therefore helping prevent white spot lesions adjacent to orthodontic brackets. (Angle Orthod. 2013;83:97-103.)