A Comparative Evaluation of Fracture Toughness of Composite Resin vs Protemp 4 for Use in Strip Crowns: An In Vitro Study

AIM: The aim of this study was to compare the fracture toughness of pedo shade packable composite resin (Z100, 3M ESPE, St. Paul, USA) vs Protemp 4 (3M ESPE, Seefeld, Germany) when used inside a strip crown to restore primary incisors. MATERIALS AND METHODS: Thirty-six exfoliated noncarious human primary central and lateral incisors were randomly divided into two equal groups. The teeth were prepared to standardized dimensions to receive a strip crown. All the teeth were etched, rinsed, and dried following which bonding agent was applied and light cured. In group I, pedo shade packable composite resin (Z100, 3M ESPE, St. Paul, USA) was packed into strip crowns, placed on the prepared tooth, and light cured. In group II, the strip crowns were filled with Protemp 4 (3M ESPE, Seefeld, Germany), placed on the prepared tooth, and left to autopolymerize for 10 minutes. The strip crowns were removed, and the teeth were tested using the universal testing machine until fracture. Fracture toughness of the two groups was recorded and analyzed statistically using Student's “t” test. RESULTS: The mean force required to fracture strip crowns restored with Protemp 4 (416.89 ± 124.58 N) was higher when compared with pedo shade packable composite resin (338.27 ± 130.99 N). However, statistical analysis did not show a significant difference in the fracture toughness between the two groups (p = 0.074), based on Student's “t” test results. CONCLUSION: The fracture toughness of teeth restored with Protemp 4 was comparable with pedo shade packable composite resin when used inside a strip crown. CLINICAL SIGNIFICANCE: The use of Protemp 4 is a possible alternative to pedo shade packable composite resin in restoring the primary anterior teeth, when used inside the strip crowns. The data also showed that the fracture toughness of Protemp 4 was comparable with pedo shade packable composite resin. HOW TO CITE THIS ARTICLE: Vignesh KC, Kandaswamy E, Muthu MS. A Comparative Evaluation of Fracture Toughness of Composite Resin vs Protemp 4 for Use in Strip Crowns: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):57–60.