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Accuracy of bracket positions with a CAD/CAM indirect bonding system in posterior teeth with different cusp heights

https://doi.org/10.1016/j.ajodo.2017.06.017Get rights and content

Highlights

  • Accuracy of bracket placement in CAD/CAM indirect bonding system was studied.

  • Differences in cusp height of maxillary posterior teeth did not affect accuracy.

  • Bracket placement errors were more frequent in posterior teeth with larger cusp tips.

Introduction

Our objective was to evaluate the effect of cusp height of posterior teeth (first premolar, second premolar, first molar) on the accuracy of the computer-aided design and computer-aided manufacturing (CAD-CAM) indirect bonding system.

Material

Five kinds of maxillary arch models, without attrition, were divided into 2 groups: control group (with 0.5 mm of grinding) and experimental group (with the addition of 0.5 mm of wax to the cusp tip). Rapid prototype models were printed for both groups. Transfer jigs of the individual tooth brackets were designed using a digital model. 3-dimensional program to evaluate the differences between the intended digital bracket position and actual bracket position after indirect bonding. The differences were measured in the linear (mesiodistal, buccolingual, vertical) and angular (angulation, rotation, torque) dimensions. The Wilcoxon signed rank test was used for statistical analyses; significance was defined as P <0.05.

Results

Both groups had similar frequencies of errors between the intended and actual bracket positions. The frequencies of vertical errors over 0.5 mm were 3.3% and 6.7% in the control and experimental groups, respectively. The frequencies of angulation, rotation, and torque errors over 1° were 53.3%, 43.3%, and 60%, respectively, for the control group; and 60%, 60%, and 73.3%, respectively, for the experimental group.

Conclusions

A difference in cusp height of maxillary posterior teeth did not produce a statistically significant difference in the linear and angular dimensions of bracket placement with the CAD/CAM indirect bonding system. However, given the tendency for a higher frequency in bracket placement errors in posterior teeth with larger cusp tips, cusp height should be considered when using a CAD/CAM indirect bonding system.

Section snippets

Material and methods

Five maxillary plaster models were chosen; they had no evidence of attrition, lacked a distinctive cusp tip, and were characterized by mild crowding (<3 mm). The experimental plaster models also had no evidence of the following traits: tooth malformation, congenitally missing teeth, and sink depth and protrusion in the buccal surface. The chosen models were modified accordingly into the control models and the experimental models. The right and left posterior teeth (first premolars, second

Results

In the comparison of mean errors in bracket positions according to cusp height of posterior teeth, mean mesiodistal errors were 0.09 ± 0.09 mm in the control group and 0.05 ± 0.01 mm in the experimental group for first premolars, second premolars, and first molars. Buccolingual errors were measured at 0.08 ± 0.05 mm and 0.11 ± 0.07 mm, and vertical errors were 0.14 ± 0.14 mm and 0.19 ± 0.2 mm in the control and experimental groups, respectively. Mean angulation errors were 1.53° ± 1.57° and

Discussion

This experiment was planned to compare accuracy in bracket position with a CAD/CAM indirect bonding system by cusp height in maxillary posterior teeth. Posterior teeth with normal attrition were set as the control groups, and those with maximum cusp height were set as the experimental groups. Intended bracket position by CAD/CAM and actual bracket position after indirect bonding were compared.

Accurate bracket positioning is an important factor in treatment with straight wire appliances, and it

Conclusions

Mean errors in the control and experimental groups were not significantly different in the statistics. Error frequencies over the clinical limit in the experimental group were higher in general than those in the control group. Frequencies over 0.5 mm in vertical errors were 6.7% in the experimental group, although those of mesiodistal and buccolingual errors in both groups were not shown. Error frequencies of angulation, rotation, and torque over 1° in the experimental group were higher than in

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    All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.

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