Discussion
Loss of retention, fracture, bond failure, tooth
ADHESION
In this study, two different classes of resin composites were utilised for the restoration of occlusal surfaces of the first permanent molars in paediatric dental patients. The clinical effectiveness of a nanofill (Filtek™ Z350XT) resin composite was compared with an alkasite (Cention NDespite both groups demonstrating clinically acceptable outcomes, some results were noteworthy in both groups. In Group 1 (nanocomposite), Bravo scores were obtained in three restorations for marginal discolouration and one restoration for surface texture at the end of the evaluation. In Group 2 (alkasite), three restorations scored Bravo for anatomic form, surface roughness and marginal discolouration each, while one restoration each had a Bravo score for marginal adaptation and fracture at the end of the evaluation.A fracture is a complete or incomplete break in the restorative material, during the application of force and has been the primary cause of failure of resin composite restorations (Jayashankara et al. Both materials showed clinically acceptable levels of marginal discolouration and marginal integrity in all restorations, which is explained by their low polymerisation shrinkage properties. Marginal adaptation of the material depends on forces produced due to polymerisation shrinkage that causes debonding of the material at the tooth interface, often leading to discolouration at the margins (Yazici et al. Similar results for nanofilled composite have been reported in a study, where most of the nanocomposite restorations received Alpha and Bravo scores for marginal adaptation after a 30-month follow-up (de Andrade et al. Loss of marginal adaptation can also occur due to localised bond failure. While etching with phosphoric acid increases the bond strength to enamel, it decreases the bond strength to dentin leading to adhesion failures. Hence, it is recommended that only enamel should be selectively etched (van Landuyt et al. Loss of retention was not reported in both groups, which is explained by the bond strength of both the restorative materials and their mechanical properties such as wear resistance, modulus of elasticity and flexural strength reported in earlier studies on nanocomposite and alkasite (Alzraikat et al. Filtek™ Z350 nanocomposite has higher filler loading and smaller-sized filler particles, enabling a reduction in the interstitial spaces. This preserves the soft resin matrix and lowers filler particle loss on the surfaces, improving wear resistance and maintaining the smooth surface texture of the restoration (de Paula et al. The results of our research showed that the clinical effectiveness of Cention NBased on the literature search done for this study, this randomised controlled trial with nanocomposite as the positive control group is the first of its kind conducted among paediatric dental patients. Composite resin restoration on a permanent first molar in children has more limitations than in adult patients, due to its proximity to the gingiva and lack of patient compliance, both of which affect isolation (Donly and Garcia-Godoy The limitations of the study include a short follow-up period and an assessment of post-operative sensitivity subjectively based on the participant’s response. The study used a parallel design that results in inter-participant variability, thus introducing selection bias (Lesaffre et al. 