Luting indirect restorations with resin cements versus composite resins: Effects of preheating and ultrasound energy on film thickness

Objective This study aims to evaluate and compare the film thickness obtained with a resin cement and two composite resins, preheated and/or ultrasonically vibrated, as luting agents. Materials and methods One hundred and twenty‐six (126) pairs of resin discs were randomly assigned to six experimental groups (n = 21) according to luting agent (Variolink Esthetic LC, IPS Empress Direct or Estelite Omega) and cementation technique (preheating at 68°C and/or ultrasonic vibration). Specimens were luted by applying a controlled force. Following sectioning and film thickness measurement through field emission gun scanning electron microscopy, statistical analysis was carried out considering a 5% significance level. Results Statistically significant lower film thickness was observed in Variolink Esthetic LC group when compared to all composite resin groups (p