This study determined the influence of surface treatment and protracted ageing on the shear bond strength (SBS) of orthodontic brackets bonded to CADCAM (milled) and 3D-printed polymethylmethacrylate (PMMA) provisional crowns (PCs). Eighty disc-shaped specimens [forty milled (CopraTemp WhitePeaks) [group (Gp) M] and forty printed (Asiga DentaTooth) (Gp P)] were divided into eight subgroups (Gp) based on surface treatment [no treatment (control) (Gp MC and Gp PC), coarse diamond (Gp MCD and Gp PCD), fine diamond (Gp MFD, and GP PFD) and sandblast (Gp MSB and Gp PSB)]. Orthodontic brackets were bonded (Assure Plus, Transbond XT), thermocycled (2200 cycles), and tested for SBS and failure (Adhesive Remnant Index) (ARI). Statistical tests included analysis of variance (ANOVA); Kruskal–Wallis (ARI ranks); and post hoc (Tukey, Dunn, and Bonferroni) for determining group differences at predetermined probability p-values less than 0.05. SBS was significantly increased in Gp MSB (15.51 Mpa) and Gp PSB (14.11 Mpa), while the coarse diamond subgroups yielded the lowest mean SBS values [Gp MCD (11.28 Mpa) and Gp PCD (11.62 Mpa)]. The SBS of subgroups MFD, MSB, PCD, and PSB showed significant differences from those of their respective controls (Gp MC and Gp PC). Low ARI scores were observed in Gp MC (0.40) and Gp MSB (0.80), while higher scores were observed in Gp PCD (2.10). Both milled and printed PCs fulfil the clinical criteria of the minimum SBS for orthodontic brackets for long-term use. However, milled PC has better SBS and low ARI scores, which make it more clinically feasible for orthodontic treatments.

BACKGROUND Fear of discomfort can affect children's behavior. This study aimed to compare pain and anxiety levels of children undergoing dental restoration using a conventional technique and INJEX. MATERIAL AND METHODS A split-mouth, randomized controlled study was conducted on 25 children aged between 7 to 10 years. Children who required restoration were randomly allocated to one of the 2 groups: Group I (traditional system) and Group II (INJEX) [25 teeth in each group]. Following standard behavior guidance, a single operator delivered anesthesia. After 3 minutes, the restoration was performed. Pain intensity was assessed using Face, Legs, Activity, Cry, and Consolability (FLACC) and Wong-Baker Faces Rating Pain scale (WBS), while child behavior was assessed using the Frankl Behavior Rating scale (FBRS). RESULTS Significant differences (P value <0.001) were observed between the 2 groups when the FLACC scores were analyzed during the administration of local anesthesia. There was a notable difference (P value <0.001) found in the WBS scores before and after injection, among which higher scores [4(2,6)] were observed in the traditional system group. CONCLUSIONS INJEX technique manifested benefits in the form of reduction in pain intensity levels felt by children, and their attitudes remained positive throughout the restorative procedure, which improve the experiences of both the child and the dental practitioner. The INJEX system could be a versatile alternative to the conventional technique. INJEX can be used to reduce preoperative fear and postoperative pain and the amount of anesthesia delivered.