Objective: Comparative evaluation of antibacterial and anti-adherent properties of surface-modified stainless steel (SS) orthodontic brackets against Streptococcus mutans ( S. mutans). Materials and Methods: The study was conducted on 120 SS orthodontic McLaughlin, Bennett, Trevisi (MBT) 0.022″ slot by Leone, Italy. Orthodontic brackets that constituted the sample size were divided into 6 groups, consisting of 20 samples each in two control (non-surface coated) and four experimental groups. The experimental group’s surface coatings were photocatalytic zinc oxide (ZnO) and photocatalytic titanium oxide (TiO2), which were carried out by radiofrequency (RF) magnetron sputtering method for surface modification. Brackets were subjected to microbiological tests against S. mutans. For anti-adherence, weight change, pre- and postexposure, was evaluated to gauge the adherence of bacteria and colony-forming units/milliliter (CFU/mL) count measuring the survival rate of bacterial cells for antibacterial activity. Results: The TiO2-coated group showed statistically significant anti-adherence ( P-value < .05) against S. mutans than control and ZnO groups. The CFU count of TiO2 group was lower than control as well as ZnO group. Conclusion: TiO2 is superior to ZnO and should be continued to be considered for surface modification of orthodontic brackets against White Spot Lesions (WSLs) and gingivitis.

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Introduction: Single crowns or fixed partial dentures retainers usually get dislodged due to inadequate resistance form. Hence, it is prudent to evaluate features of a tooth preparation, which can prevent these failures. Aim: To evaluate the effect of auxiliary features, occlusal surface modifications, and total occlusal convergence (TOC) on the resistance of a full veneer crown. Materials and Methods: An ivorine mandibular molar tooth was prepared with features of inadequate resistance form, i.e., 2.5 mm axial wall height and TOC of 20°. Seven auxiliary preparation features were subsequently added one by one to it. They were mesiodistal grooves, buccolingual and mesiodistal grooves, buccolingual grooves, mesiodistal boxes, occlusal inclined planes, 8° reduced TOC in the cervical aspect, and mesiodistal grooves added to 8° reduced TOC in the cervical aspect. Ten dies with their respective crowns were prepared for each group. Resistance testing of all the samples was performed on the INSTRON testing machine. Results: Modification of the overtapered die preparation by reducing the TOC to 8° in the cervical 1.5 mm of the axial wall and then subsequently adding mesiodistal grooves to the reduced TOC cervically offered the greatest resistance to dislodgment statistically. Conclusion: For an overtapered preparation, reducing the TOC to 8° in the cervical aspect and subsequently adding proximal grooves can provide maximum resistance form.