Debonding forces of different pads in a lingual bracket system

ABSTRACT Objective: To evaluate the shear bond strength of lingual orthodontic brackets with resin or metal pads, the location of bond failure and the adhesive remnant index (ARI). Methods: A total of 40 extracted upper premolars were randomly divided into two groups of 20 each: bonding with brackets having (1) pads with extended resin directly on the lingual surface of teeth, and (2) pads with metal custom base on the lingual surface of teeth. The debonding force was measured with an Instron universal testing machine. A Student’s t-test was used to assess the difference between groups (α = 0.05). Results: The results showed a significant difference between the groups (p < 0.001). The shear bond strength of metal pads was significantly higher than resin pads. Conclusions: Within the limitations of this in vitro study, it was concluded that the bond strength of lingual brackets with metal pads was higher than that of brackets with composite resin pads, due to the metal part being a single unit and welded. The failure location in the region between the bracket and the resin pad affected a higher percentage of the resin pads than the metal pads

Evaluation of miniscrew angulation in the posterior maxilla using cone-beam computed tomographic image

ABSTRACT Objective: This study aimed at evaluating whether changes in the insertion angle is a determining factor in the positioning of the miniscrews body in a region with larger interradicular space in the posterior maxilla. Methods: Analysis of 60 posterior maxillary quadrants were made using images obtained by means of cone-beam computed tomographic image (CBCT), with 0.076-mm voxel, which presented a real miniscrew inserted in the mesial region of the maxillary first molars, serving as reference point for the placement of the virtual miniscrews. Measurements of the distances between roots were made in three points on the body of the virtual miniscrews (A, B and C), at four different angulations, 70o, 60o, 50o and 40o (T1 to T4), in relation to the long axis of the second premolar. This evaluation was made in four groups, selected in accordance with the disposition of the roots of the second premolars and first molars: Group 1 (all types of roots), Group 2 (convergent roots), Group 3 (divergent roots) and Group 4 (parallel roots). Results: There were no statistically significant differences in the measurements of points A, B and C, at the different angles (70o, 60o, 50o and 40o) and in the different groups (p > 0.05). Conclusions: Changes in the insertion angle is not a determinant factor in the positioning of miniscrews body in regions with larger interradicular space in posterior maxilla

Transient global amnesia after prolonged and abnormal head posture.

[No abstract available

Exploring the perception of orthodontic treatment need using the dental aesthetic index and index of orthodontic treatment need

Introduction: This study aimed to explore the perception of orthodontic treatment need by using the Dental Aesthetic Index (DAI) and the Index of Orthodontic Treatment Need (IOTN). Methods: A cross-sectional study was conducted on a representative random sample (N = 248) of adolescents aged 12 years. The DAI and both components of IOTN were used to evaluate malocclusion. The association between the Dental Health Component of the IOTN with gender and ethnic group were analyzed by chi-square test. The concordances between the indexes were analyzed by the kappa statistic, with 95% confidence intervals (Cis). Results: The prevalence of adolescents with high severity and orthodontic treatment need was 10.5% (95% CI, 6.7-14.3), 36.5% (95% CI, 32.3-44.3), and 73.4% (95% CI, 67.9-78.9) for the Aesthetic Component of the IOTN, Dental Health Component of the IOTN, and DAI, respectively. The indexes showed high agreement for the cases with low treatment need, whereas low concordance was observed for the cases with high treatment need. Conclusion: The perception of orthodontic treatment need was assessed differently using DAI and IOTN156681882

Evaluation of miniscrew angulation in the posterior maxilla using cone-beam computed tomographic image

<div><p>ABSTRACT Objective: This study aimed at evaluating whether changes in the insertion angle is a determining factor in the positioning of the miniscrews body in a region with larger interradicular space in the posterior maxilla. Methods: Analysis of 60 posterior maxillary quadrants were made using images obtained by means of cone-beam computed tomographic image (CBCT), with 0.076-mm voxel, which presented a real miniscrew inserted in the mesial region of the maxillary first molars, serving as reference point for the placement of the virtual miniscrews. Measurements of the distances between roots were made in three points on the body of the virtual miniscrews (A, B and C), at four different angulations, 70o, 60o, 50o and 40o (T1 to T4), in relation to the long axis of the second premolar. This evaluation was made in four groups, selected in accordance with the disposition of the roots of the second premolars and first molars: Group 1 (all types of roots), Group 2 (convergent roots), Group 3 (divergent roots) and Group 4 (parallel roots). Results: There were no statistically significant differences in the measurements of points A, B and C, at the different angles (70o, 60o, 50o and 40o) and in the different groups (p > 0.05). Conclusions: Changes in the insertion angle is not a determinant factor in the positioning of miniscrews body in regions with larger interradicular space in posterior maxilla.</p></div

Debonding forces of different pads in a lingual bracket system

<div><p>ABSTRACT Objective: To evaluate the shear bond strength of lingual orthodontic brackets with resin or metal pads, the location of bond failure and the adhesive remnant index (ARI). Methods: A total of 40 extracted upper premolars were randomly divided into two groups of 20 each: bonding with brackets having (1) pads with extended resin directly on the lingual surface of teeth, and (2) pads with metal custom base on the lingual surface of teeth. The debonding force was measured with an Instron universal testing machine. A Student’s t-test was used to assess the difference between groups (α = 0.05). Results: The results showed a significant difference between the groups (p < 0.001). The shear bond strength of metal pads was significantly higher than resin pads. Conclusions: Within the limitations of this in vitro study, it was concluded that the bond strength of lingual brackets with metal pads was higher than that of brackets with composite resin pads, due to the metal part being a single unit and welded. The failure location in the region between the bracket and the resin pad affected a higher percentage of the resin pads than the metal pads.</p></div