Saranya, A (2020) Comparative study of Shear Bond Strength and Surface Changes with Labial and Lingual Brackets: An In Vitro study. Masters thesis, Madha Dental College and Hospital, Chennai.
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Abstract
AIM OF THE STUDY: To evaluate and compare the shear bond strength of bonded labial and lingual stainless steel maxillary and mandibular brackets and to assess the surface changes in enamel using Profilometry. MATERIALS AND METHODS: 40 extracted premolar teeth were selected for this study. These teeth were divided into 4 groups as 10 in each group. Group A- Labial maxillary premolar brackets; Group B-Labial mandibular premolar brackets; Group C- Lingual maxillary premolar brackets; Group D- Lingual mandibular premolar brackets. Freshly extracted teeth were cleaned to remove blood or any tissue debris and stored in distilled water solution till the time of bonding procedure. Teeth were then mounted on self-cured, color-coded acrylic blocks of dimensions 35 x 7 x 7mm. The acrylic blocks are color-coded to differentiate between the groups. The enamel was etched with 37% phosphoric acid gel for 30 seconds, rinsed under running water for 20 seconds, and then dried with oil and moisture-free compressed air for 20 seconds. ORMCO primer was applied to the etched surface and the bracket base as well with the help of an applicator brush. ORMCO adhesive material was next applied to the bracket base directly from the syringe. The adhesive/bracket was cured using an LED (Light-emitting diode) curing unit. The above procedure was done for all samples in Group-I to Group-IV by the same individual under the same environment. Debonding was carried out with a universal testing machine (INSTRON, 8874). The samples were then stressed at a crosshead speed of 1mm per minute in a gingival incisal direction, and the maximum force at bond failure was recorded. Adhesive remnant index score was recorded using stereomicroscope. The samples were then loaded on to optical profilometry to assess the surface roughness. With this, a 3-dimensional image is captured to identify the surface roughness in terms of extent (Sa) and depth (Sz)of enamel wear. The following statistical analysis was done to evaluate the results using the software "statistical package for social sciences" SPSS (IBM SPSS Statistics for Windows, Version 25.0, Armonk, NY: IBM Corp. Released 2017). The Normality tests Kolmogorov-Smirnov and Shapiro-Wilks tests were done. RESULTS: The results reveal that there is statistical significance seen in the mean shear bond strength value of labial brackets is 1.55mpa(±1.146) and lingual brackets are 2.80mpa(±1.542). The p-value is 0.010. There is statistically significant difference between the labial and lingual groups with regard to adhesive remnant score - p value is 0.002. There is statistically significant difference between the upper and lower groups also - p value is 0.044. The result for surface changes shows the mean value of labial brackets is 39.12 (±14.204)and lingual brackets are 72.67(±55.631). There is a statistically significant difference in Sa value between Labial brackets and lingual brackets (p-value is 0.006). The result for surface changes shows the mean value of labial brackets is 190.02 (±95.060) and lingual brackets are 407.68(±311.157). The p-value is 0.001 which reveals that it is statistically significant. CONCLUSION: In conclusion, this study shows that the shear bond strength for lingual stainless steel brackets is higher than labial stainless steel brackets and between groups, the labial upper stainless steel brackets have more shear bond strength than labial lower stainless steel brackets. Lingual lower stainless steel brackets have more shear bond strength than lingual upper stainless steel brackets. The adhesive remnant index reported that the failure zone was between the bracket adhesive interface. The surface changes show that the lingual stainless steel brackets show more damage to the enamel. Labial upper stainless steel brackets have more damage to enamel than the labial lower stainless steel brackets and lingual lower stainless steel brackets show more damage to the enamel than the lingual upper stainless steel brackets.
| Item Type: | Thesis (Masters) |
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| Additional Information: | 241719552 |
| Uncontrolled Keywords: | Shear bond strength, Instron, Profilometry. |
| Subjects: | DENTAL > Orthodontics and Dentofacial Orthopedics |
| Depositing User: | Subramani R |
| Date Deposited: | 24 Feb 2021 11:54 |
| Last Modified: | 24 Feb 2021 15:39 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/14469 |
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