Comparison of shear bond strengths of orthodontic brackets bonded with flowable composites.

This study evaluated the shear bond strengths of orthodontic brackets bonded to human premolars using five different combinations of flowable composites and one-step self-etching adhesives (n=12): (1) Adper Easy Bond+Filtek Supreme XT Flow; (2) Futurabond NR+Grandio Flow; (3) Clearfil S3 Bond+Clearfil Majesty Flow; (4) AdheSE One+Tetric EvoFlow; and (5) Transbond Plus Self Etching Primer+Transbond XT Light Cure Adhesive. After shear bond strength testing, adhesive remnant index (ARI) scores were given according to the amount of adhesive and resin remaining on the brackets. On shear bond strength, there were no statistically significant differences between Groups 2 and 4 and between Groups 3 and 5 (p>0.05). On ARI scores, the predominant ARI scores in Groups 1, 2, 3, and 5 were 4, 2, 5, and 4 respectively; in Group 4, they were 0 and 4. Results showed that some combinations of flowable composites and self-etching adhesives might not be suitable for orthodontic use due to their low shear bond strengths and high ARI scores -with the latter signaling the risk of damaging the enamel surface during debonding.

Differences in cephalometric measurements: a comparison of digital versus hand-tracing methods.

The aim of this study was to evaluate the accuracy of cephalometric measurements using computerized tracing of direct digital radiographs in comparison with hand tracing of digital radiographic printouts. Comparisons were made between methods in terms of accuracy of individual measurements as well as evaluation of treatment outcomes. Pre- (T1) and post- (T2) treatment cephalometric digital radiographs of 30 patients were traced using the Vistadent OC 1.1 computer software program (group 1) and manually (group 2) by the same investigator. A total of 26 anatomical landmarks were located and measured. Measurement reproducibility was evaluated by calculating intraclass correlation coefficients, and paired t-tests were used to compare differences in individual measurements and treatment outcomes between methods. Differences greater than 0.05 were considered to be statistically significant. Significant differences were found between the two methods for SNB, Wits appraisal, Cd-A, Cd-Gn, FMA, SN-PP, U1-NA (mm), U1-FH, L1-NB (mm), and Li-E plane. No significant differences were found between the two methods in the measurement of treatment changes. Cephalometric measurements of most parameters were reproducible for both methods. Despite some discrepancies in measured values between hand-tracing and the computerized method, any differences were minimal and clinically acceptable.

Soft tissue profile after distal molar movement with a pendulum K-loop appliance versus cervical headgear.

OBJECTIVE: To evaluate the soft tissue changes associated with the pendulum appliance that was supported with a K-loop buccally and to compare these treatment changes with a cervical headgear group. MATERIALS AND METHODS: The records of 30 patients having skeletal Class I, dental Class II malocclusions were divided to two groups. Group 1 consisted of 7 girls, 8 boys (mean age, 15.0 +/- 3.4 years), and Group 2 consisted of 10 girls, 5 boys (mean age 14.2 +/- 2.9 years). The first group was treated with a pendulum appliance that was supported with a K-loop buccally, and the second group was treated with cervical headgear. Lateral cephalograms were taken at the beginning of treatment and at the end of distal molar movement. Treatment changes within the groups were analyzed using the paired t-test, and between group changes were analyzed with the independent t-test. RESULTS: The results showed that the pendulum/K-loop appliance had no significant effect on skeletal and dental variables and soft tissue A point, upper lip thickness, and sagittal upper lip position relative to the E plane. A significant difference for the change in Vp-Ls distance was found in patients in the pendulum/K-loop group (P < .05). Patients in the cervical headgear group showed significant retrusion in skeletal, dental, and soft tissue measurements (P < .05). CONCLUSIONS: The pendulum/K-loop appliance produces distal molar movement without causing any significant changes in the sagittal or vertical positions of either the jaw or the soft tissue profile.

A comparison of white spot lesion formation between a self-ligating bracket and a conventional preadjusted straight wire bracket.

AIM: Demineralization following removal of orthodontic appliances is a common problem. Presence of archwires, especially those with loops and different types of ligatures, complicate cleaning around bands and brackets during orthodontic treatment. These factors led clinicians to develop self-ligating brackets. The purpose of this study was to compare the incidence of white spot lesion formation with the use of a self-ligating bracket with conventional preadjusted straight wire brackets. METHODS: Twenty patients were randomly divided into 2 groups. In the first group (aged 13.4 ± 2.5 years), the teeth were bonded with In-ovation brackets; the second group's (aged 14 ± 3.34 years) teeth were bonded with conventional preadjusted straight wire brackets. The patients were followed throughout treatment, and the number of white spot lesions was noted at debonding. RESULTS: The results revealed no statistically significant differences in white spot lesion development between conventional straight wire and self-ligating brackets. CONCLUSION: No differences in terms of white spot lesion formation were found between conventional straight wire and self-ligating brackets, and white spot lesion formation does depend largely on patients' oral hygiene status, not the type of bracket or ligation used.

The influence of Er:YAG laser conditioning versus self-etching adhesives with acid etching on the shear bond strength of orthodontic brackets.

OBJECTIVE: The aim of this study was to compare the shear bond strength (SBS) of orthodontic brackets after acid etching, laser ablation, self-etching primer application, and combined treatments. METHODS: One hundred defect-free premolars were randomly assigned to five groups. The teeth received the following treatments: group 1: phosphoric acid + Transbond XT primer; group 2: Transbond Plus Self-Etching Primer (TPSEP); group 3: Er:YAG laser ablation + Transbond XT primer; group 4: Er:YAG laser ablation + phosphoric acid + Transbond XT primer; and group 5: Er:YAG laser ablation + TPSEP. Transbond XT Adhesive Paste was used in all groups for bracket bonding. Samples were stored in deionized water at 37 degrees C for 24 h. The shear debonding test was performed at a crosshead speed of 5 mm/min. Failed brackets were examined by a stereomicroscope at 16 x magnification to determine the bond failure interface using a modified adhesive remnant index (ARI). SBS values were compared using one-way analysis of variance (ANOVA). The Kruskal-Wallis test was used for ARI scores and pairwise comparisons were done using the Mann-Whitney U test with Bonferroni correction. RESULTS: Mean SBS values (MPa) and standard deviations for the groups were: group 1, 13.18 +/- 3.45; group 2, 13.52 +/- 4.38; group 3, 10.33 +/- 4.74; group 4, 13.00 +/- 3.47; and group 5, 12.46 +/- 6.31. No significant differences were observed in the SBS of all the groups evaluated, but there was a significant difference in ARI scores, with group 3 showing higher ARI scores than groups 1 and 4. CONCLUSIONS: Er:YAG laser ablation and self-etching primer application showed similar SBS values as conventional acidetching for bonding brackets.