Effect of Different Chemical Solvents on Bond Strength of Orthodontic Brackets: An In Vitro Study.

AIM: The purpose of the present study was to evaluate the impact of various chemical solvents on bond strength of orthodontic brackets. MATERIALS AND METHODS: One hundred healthy human premolars with undamaged buccal surfaces that were extracted for orthodontic purposes were gathered. Using 37% orthophosphoric acid, primer, and Transbond XT adhesive, ceramic 0.018" × 0.022" slot orthodontic brackets were adhered to the tooth surface. Following thermocycling, all samples were divided into four groups, with 25 samples in each group: group I: control; group II: application of ethanol; group III: application of acetone; and group IV: application of dimethyl sulfoxide (DMSO). Following the debonding tests, a double-ocular stereomicroscope was used to inspect the tooth surfaces. Additionally, adhesive remnant index (ARI) values were evaluated at 40× magnification. Data were recorded and statistically analyzed. RESULTS: The bond strength was lesser in acetone applied group (16.18 ± 3.64) followed by DMSO applied group (22.08 ± 2.86), ethanol applied group (24.36 ± 4.02), and control group (27.14 ± 3.68). There was a highly significant difference found between the chemical solvents group. The ARI score 3 was present in control (12%), ethanol (8%), and DMSO (4%), and it was absent in acetone applied group. The ARI score 0 was more in acetone applied group (24%). CONCLUSION: The present study concluded that the reduced debonding force was found with the application of acetone solvent followed by DMSO, ethanol, and control groups. Applying acetone can be a substitute technique to help with ceramic bracket debonding. CLINICAL SIGNIFICANCE: Orthodontic bracket debonding cannot occur without shear bond strength (SBS). The need for an ideal debonding technique for ceramic brackets without negative consequences arises from the risk of enamel damage that frequently follows the process. Acetone treatment prior to ceramic bracket debonding could be an alternate clinical technique to preventing enamel damage and facilitating debonding. How to cite this article: Bhushan R, Singh S, Sam G, et al. Effect of Different Chemical Solvents on Bond Strength of Orthodontic Brackets: An In Vitro Study. J Contemp Dent Pract 2023;24(12):940-943.

Botulinum Toxin Type-A for the Treatment of Excessive Gingival Display on Smiling.

AIM AND OBJECTIVE: To determine the effect of botulinum toxin type-A (BTX-A) in reducing gummy smile. MATERIALS AND METHODS: This was an interventional case series conducted at a tertiary care setting in Mangaluru, Karnataka, India. Twenty patients with the gingival display of >3 mm were selected through convenience sampling technique. 2.5 units of BTX-A were injected under sterile conditions on either side of the face. The effect of the injection on gingival display was measured at the interval of 2, 4, 12, and 24 weeks. At the end of the treatment, the patient was asked to smile and was photographed and was compared to pretreatment photo. Repeated measures analysis of variance (ANOVA) was used to detect the change at each interval and intergroup comparisons were performed using post hoc Bonferroni test. RESULTS: The mean gingival exposure reduction from 4.93 to 3.705 mm at week 2. At the end of 24 weeks, the evaluation showed the mean gingival display of 4.755 mm on administration of 2.5 units on either side. The photographs also showed the change in smile at the end of the treatment. CONCLUSION: From the study, it was inferred that botulinum toxin was effective in eliminating gummy smile along with noticeable decrease in the nasolabial fold despite for the effect lasting only about 24 weeks. CLINICAL SIGNIFICANCE: A nonsurgical method of correction of gummy smiles when compared to surgical intervention is readily accepted by patients. Botulinum toxin type-A for gummy smiles is an effective, conservative, and satisfactory technique.

Evaluation of Micro-organism in Ligated Metal and Self-ligating Brackets using Scanning Electron Microscopy: An In Vivo Study.

BACKGROUND: The objective of the study was to determine the sites of plaque accumulation and to compare the plaque accumulated with metal and self-ligating orthodontic brackets in order to know which bracket type had a higher plaque retaining capacity. MATERIALS AND METHODS: The study was done on 20 subjects who were scheduled for orthodontic treatment including extraction of four premolars and fixed orthodontic appliances. Mesh-backed edgewise metal brackets ligated with steel ligatures and self-ligating brackets were bonded to the premolars to be extracted using composite (Transbond XT, 3M). The subjects were told to continue their normal oral hygiene regimen. Teeth were extracted at 1, 2, and 3 weeks after bracket bonding. Plaque attached to the buccal surfaces was stained using plaque disclosing agent. The teeth were then immersed in fixative containing 4% formaldehyde and 1% glutaraldehyde in phosphate buffer for 24 h, followed by 0.1 M phosphate buffer for 12 h. The specimens were then mounted on aluminum stubs, and sputter coated with gold prior to Scanning electron microscopy examination. RESULTS: The results showed that increased retention of plaque in metal brackets ligated with steel ligatures and comparatively less in self-ligating brackets at the base of the brackets. CONCLUSIONS: This study highlights that higher retention of plaque in metal brackets ligated with steel ligatures and comparatively less plaque retention in self-ligating brackets. Excess composite around the bracket base is the critical site of plaque accumulation associated with fixed appliances due to its rough surface texture.