kiyomars sadri; Arman Mohammadi Shayan; Ahmad Behroozian; Parya Fathi
Abstract
Background: Debonding of orthodontic metal bracket is a routine part of fixed orthodontic treatment. The purpose of this in vitro study was to evaluate the direction of enamel cracks before and after debonding the metal orthodontic brackets in five different techniques.Methods: Two hundred extracted ...
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Background: Debonding of orthodontic metal bracket is a routine part of fixed orthodontic treatment. The purpose of this in vitro study was to evaluate the direction of enamel cracks before and after debonding the metal orthodontic brackets in five different techniques.Methods: Two hundred extracted human premolars were randomly divided into five groups in this in vitro study. Metal brackets were bonded with Transbond XT (3 M Unitek, Monrovia, CA, USA) light-cured adhesive. Then the brackets were removed with one of these methods: ultrasonic scaler, ligature cutter plier, bracket removal plier, how plier, crown remover. Direction of the enamel cracks were examined by stereomicroscope and compared. Statistical analysis was done with Paired t-test and Chi-squared test. P < 0.05 was considered as significant.Results: After debonding, mixed type had the highest frequency (80.9 %) and no specimens were observed with horizontal crack. There was no significant change in the pattern of directions in before-after comparison (p=0.007. Mixed pattern was less common in ultrasonic group compared to crown remover and ligature cutter groups (p=0.007 and 0.035 respectively).Conclusion: All of the five debonding methods in the current study had no significant change on the microcrack patterns and there were no horizontal cracks after debonding. Ultrasonic device had the least number of mixed cracks after debonding.
Mohammad Karim Soltani; Sadegh Barkhori; Yoones Alizadeh; Farzaneh Golfeshan
Abstract
Background: Brackets’ debonding without any damage to the teeth is very important.
Objectives: The aim of this study was to compare the debonding characteristics of the metal conventional and self-ligating brackets.
Patients and Methods: 69 maxillary premolars were randomly assigned in 3 groups. ...
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Background: Brackets’ debonding without any damage to the teeth is very important.
Objectives: The aim of this study was to compare the debonding characteristics of the metal conventional and self-ligating brackets.
Patients and Methods: 69 maxillary premolars were randomly assigned in 3 groups. Metal brackets of Damon, In Ovation and conventional systems were bonded to the teeth. The brackets were debonded with debonding pliers. Debonding strengths, adhesive remnant index, and enamel damage were evaluated. A Zwick model universal testing machine was used to measure debonding strengths. The debonding strength values were statistically analyzed by one sided analysis of variance while the increase in the enamel crack numbers and length and the remained adhesive index were analyzed by chi-square test.
Results: The means of the debonding strength in the brackets of in ovation, damon and conventional systems were 15.22, 11.4 and 8.67 MPa respectively. Significant differences were observed regarding debonding strength between three types of brackets (all: P < 0.001). After debonding of in ovation, damon and stainless steel brackets; the increased numbers of the enamel cracks were noted in 26.06%, 21.74% and 17.39% cases respectively. Also, the increased cracks lengths were demonstrated in 47.83%, 39.13%, and 30.43% cases. No significant differences were observed regarding the increase of the enamel cracks number and length and the amounts of residual adhesive on the teeth.
Conclusions: The debonding characteristics of the metal self-ligating were comparable to the conventional brackets.
