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Objective: To investigate if there are any significant differences in the final inclination of the upper and lower anterior teeth of patients treated with a Roth or an MBT bracket prescription. Materials and Methods: Forty sets of posttreatment study models from patients treated using a preadjusted edgewise appliance (20 Roth and 20 MBT) were selected using predetermined inclusion and exclusion criteria. The models were masked and laser-scanned, and the final crown inclinations of UL1, UR3, and LR1 were assessed from the digital images. A two-way analysis of variance was undertaken with the dependent variable of final crown inclination and independent variables of bracket prescription (Roth or MBT) and tooth type. Results: There were no statistically significant differences in terms of the final inclination of the anterior teeth between the two bracket prescriptions (P = .132). Statistically significant differences were found between the final inclinations of different tooth types investigated (P<.001). Conclusion: In this group of selected patient records, the differences in torque values between the two bracket prescriptions did not lead to any real clinically detectable differences in the final inclination of teeth. [ABSTRACT FROM AUTHOR]

Objective: To investigate the change in the physical properties of conventional and Super Slick elastomeric ligatures after they have been in the mouth. Materials and Methods: Nine healthy volunteers took part. One orthodontic bracket was bonded to a premolar tooth in each of the four quadrants of the mouth. Two conventional and two Super Slick elastomeric ligatures were placed at random locations on either side of the mouth. The ligatures were collected after various time intervals and tested using an Instron Universal testing machine. The two outcome measures were failure load and the static frictional resistance. Results: The failure load for conventional ligatures was reduced to 67% of the original value after 6 weeks in situ. Super Slick elastomeric ligatures showed a comparable reduction after 6 weeks in situ (63% of original value). There were no statistical differences in the static friction between conventional and Super Slick elastomerics that had been in situ for either 24 hours (P = .686) or 6 weeks (P = .416). There was a good correlation between failure load and static friction (r = .49). Conclusions: There were statistically significant differences in the failure loads of elastomerics that had not be placed in the mouth and those that had been in the mouth for 6 weeks. There were no differences in the static frictional forces produced by conventional and Super Slick ligatures either before or after they had been placed in the mouth. There appears to be a direct proportional relationship between failure load and static friction of elastomeric ligatures. [ABSTRACT FROM AUTHOR]

Objective: To compare the assessment of demineralized white lesions surrounding orthodontic brackets using images produced with and without polarizing filters to reduce incidental flash reflection. Materials and Methods: Thirty teeth with orthodontic brackets and a systematic arrangement of artificially induced demineralization were used. Standardized digital images of the teeth were taken with and without a cross-polarizing filter. These were repeated after 1 week. All the images were randomly numbered and assessed by an investigator, unaware as to the nature of the study. The presence or absence of demineralization was recorded and compared with the actual demineralization pattern. The lesion area and degree of whiteness (LI%) were measured using computerized image analysis. Twenty images from each group were randomly chosen and duplicated for an assessment of measurement error. Results: The positive and negative predictive values were better from the polarized images (0.97 and 0.84, respectively) than from the nonpolarized images (0.90 and 0.74, respectively). The percentage agreements for the repeat assessments of the same slide were better for the polarized images (96%) than for the nonpolarized images (89%). The limits of agreement and intraclass correlation coefficients between measurements of repeated images were lower for lesion area from cross-polarized images, suggesting better reproducibility, but not for LI%. Conclusion: A cross-polarization filter enhances the subjective assessment of demineralized lesions surrounding an orthodontic bracket and improves the reproducibility of measuring the lesion area. The filter did not improve the assessment of changes in enamel gray levels with demineralization. [ABSTRACT FROM AUTHOR]

Digital images provide an efficient means of processing and storing clinical images and are increasingly being used in orthodontic practice. However, for research purposes it must be shown that measurements from digital images are as reliable as those from captured slides, particularly in the area of postorthodontic demineralization. The aim of this in vitro study was to compare the assessment of demineralized white lesions surrounding orthodontic brackets using images produced from captured slides with those from a digital camera. Thirty teeth with orthodontic brackets and a systematic arrangement of artificially induced demineralization were used. Standardized images of the teeth were taken in 35-mm slide format and using a digital camera. The slides were scanned and saved as digital images. All the images were numbered, recoded in a random order, and assessed by a second investigator. The image was examined for the presence or absence of demineralization. This was compared with the actual demineralization pattern, and the positive and negative predictive values were calculated. Twenty images from each group were randomly chosen and duplicated for an assessment of measurement error. The positive and negative predictive values were better from the digital images (0.92 and 0.81) than from the captured slides (0.88 and 0.74). The percentage agreements for the repeat assessments of the same slide were similar (96% for the captured slides and 93% for the digital images). Measurements of enamel demineralization using images from a digital camera are as accurate and reproducible as images captured from a photographic slide. [ABSTRACT FROM AUTHOR]

Several letters to the editor are presented in response to the article "Validation of a modified McGill Pain Questionnaire for orthodontic patients," by L. R. Iwasaki and colleagues in the 2013 issue.

Objective: To investigate the change in the physical properties of conventional and Super Slick elastomeric ligatures after they have been in the mouth., Materials and Methods: Nine healthy volunteers took part. One orthodontic bracket was bonded to a premolar tooth in each of the four quadrants of the mouth. Two conventional and two Super Slick elastomeric ligatures were placed at random locations on either side of the mouth. The ligatures were collected after various time intervals and tested using an Instron Universal testing machine. The two outcome measures were failure load and the static frictional resistance., Results: The failure load for conventional ligatures was reduced to 67% of the original value after 6 weeks in situ. Super Slick elastomeric ligatures showed a comparable reduction after 6 weeks in situ (63% of original value). There were no statistical differences in the static friction between conventional and Super Slick elastomerics that had been in situ for either 24 hours (P = .686) or 6 weeks (P = .416). There was a good correlation between failure load and static friction (r = .49)., Conclusions: There were statistically significant differences in the failure loads of elastomerics that had not be placed in the mouth and those that had been in the mouth for 6 weeks. There were no differences in the static frictional forces produced by conventional and Super Slick ligatures either before or after they had been placed in the mouth. There appears to be a direct proportional relationship between failure load and static friction of elastomeric ligatures.