Texila International Journal of Public Health ISSN: 2520-3134 DOI: 10.21522/TIJPH.2013.12.02.Art034 Received: 10.06.2024 Accepted: 17.06.2024 Published on: 28.06.2024 *Corresponding Author: aravindkumar@saveetha.com An In-Vitro Comparative Evaluation of Microleakage Beneath Metal Orthodontic Brackets when Bonded using Conventional and Titanium Dioxide Nanoparticle Infiltrated Orthodontic Adhesive Resin Harsha L, Aravind Kumar Subramanian* Department of Orthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai–600077, India Abstract The objective of this present study was to evaluate and compare the microleakage underneath metal orthodontic brackets when bonded with conventional and Titanium dioxide nanoparticle-infiltrated orthodontic adhesive. Ten human caries-free premolars were extracted atraumatically for orthodontics purposes and were randomly allotted into two groups, Group 1: Conventional orthodontic adhesive resin- An acid-etching adhesive system: Enlight composite (ORMCO) and Group 2: An Experimental acid-etching orthodontic adhesive system that was infiltered with Titanium dioxide. An orthodontic adhesive containing 1% nanoparticle was prepared. The metal brackets were bonded to the teeth using the adhesive group to which they belonged. All specimens underwent thermocycling in deionized water for 1000 cycles with a dwell time of 30 seconds and a transfer time of 0 seconds after being stored at 37°C for four weeks in distilled water. The next step involved 24 hours of submersion in a 0.5% basic fuchsin solution. With a low-speed diamond saw, four parallel bucco-lingual longitudinal sections were cut through the occlusal surface. Two calibrated researchers who were blindfolded were examined with a stereomicroscope at a magnification of 16x. Every section's incisal and gingival margins were measured between the bracket-adhesive and adhesive-enamel interfaces. The collected data were tabulated, and the Shapiro-Wilk test for normality was done. At the enamel adhesive interface and the bracket adhesive interface, brackets bonded with the experimental TiO2 infiltrated orthodontic adhesive resin had higher mean microleakage scores than brackets bonded with conventional composite. However, this difference was only statistically significant at the enamel adhesive interface (p > 0.05). Keywords: Adhesives, Nanoparticles, Orthodontic Brackets, Titanium Oxide. Introduction Fixed orthodontic treatment involves the provisional attachment of appliances like orthodontic brackets via adhesive resin cement onto the tooth surface to aid in orthodontic movement of the teeth. Though this is common practice, this increases the risk of plaque accumulation and carious lesions on bonded teeth. It was found that enamel decalcification following orthodontic therapy can be seen in 2- 96% of the patients. Over time white spot lesions (WSLs) can also be noted due to an increase in the porosity of the surface. Also impedes oral hygiene maintenance by the patient [1, 2]. Most adhesive cement used has a matrix of bis-GMA (bis-phenol A glycidyl methacrylate). These are often associated with certain water sorption, solubility, lower DC (degree of conversion) and polymerization shrinkage [3, 4]. The precursors for bis-GMA are GMA (glycidyl methacrylate) and BPA (bis-phenol- A), BPA has been reported as carcinogenic which stimulates certain cytotoxic responses as skin hypersensitivity reactions, hemolytic 1