Comparative evaluation of the degree of conversion of four different composites polymerized using ultrafast photopolymerization technique: An in vitro study

Abstract

Context: Lower degree of conversion (DC%) of monomer to polymer in a resin composite restoration could be a health hazard for the patient as well as it could affect the longevity of the restoration. Aims: This study is aimed to compare and evaluate the DC% of four different composites polymerized using ultrafast photopolymerization. Settings and Design: In-vitro study. Materials and Methods: A total of 40 disc-shaped composite samples were used in the study. Twenty samples were prepared for each group using 2 mm height and 6 mm diameter Tygon tube as a matrix. All of the composites were cured using the Woodpecker i Led light-curing unit with an intensity of 2300–2500 mW/cm 2 (TURBO mode). Samples in Group 1 were cured for 1 s and samples in Group 2 were cured for 3 s. Each group had 4 subgroups of five samples of the 4 resin composites tested. After photo-activation, the specimens were stored under dark dry conditions at room temperature for 24 h before testing. The DC% was measured using Fourier-transform infrared spectroscopy. Statistical Analysis Used: The DC% were analyzed using ANOVA, and Tukey HSD post hoc test using IBM SPSS 21 software. Results: Among the experimental groups, Group 2 showed a higher DC% which ranges from 93.7% to 95.4% than Group 1 which ranges from 58.5% to 65.5%. There was a statistically significant difference in the DC% among the materials tested ( P < 0.05). Conclusions: Within the limitations of the study, it was concluded that composites cured for 3 s showed a higher DC% which ranges from 93.7% to 95.4% than those cured for 1 s. The DC% also varied among the four different composites tested.

Monomer Elution from Three Resin Composites at Two Different Time Interval Using High Performance Liquid Chromatography—An In-Vitro Study

“…During polymerization, conversion of monomer to polymer is termed as degree of conversion [6]. In other words, degree of conversion means the percentage of reacted C=C bond from the monomers present in polymeric matrices.…”

effect of light-curing distance on the degree of convergence of the top and bottom sides of flowable bulk-fill composite materials

“…An incomplete or low degree of convergence can affect the restoration performance as uncured monomers are potentially leachable and can act as plasticizers, reducing the mechanical properties of the resin. When these uncured monomers are in a low amount within the composite resin, more biocompatible and extended restoration longevity is expected (Balagopal et al, 2021).…”

“…When DC levels are insufficient, mechanical qualities such as tensile strength, flexural modulus, and temperature resistance are affected, and color stability may deteriorate. Insufficient DC % may increase cytotoxicity, wear, marginal degradation, and microleakage (Balagopal et al, 2021). Human gingival fibroblasts were discovered to be poisoned by monomers produced by inadequate DC % resin composites.…”

“…Since they are secreted into saliva and diffuse into the tooth pulp, gingiva mucosa, and salivary glands, they may contribute to cancer by immortalizing human keratinocytes (Kleinsasser et al,2006). When high DC % is reached, the amount of such harmful leachable chemicals is minimized (Balagopal et al, 2021). In bulk-fill composites, the high translucency and equivalent refractive indices of the organic matrix and filler particles allowed sufficient light to flow through and polymerize the deeper layers.…”

Microhardness Evaluation of Microhybrid Versus Nanofilled Resin Composite After Exposure to Acidic Drinks

“…[ 7 8 ] Hybrid and microhybrid resin composites have a broad range of particle sizes, macrofillers of an average size of 0.1 6.0 μm and microfillers with a particle size of 0.01-0.05 μm. [ 9 ] Thus allow high filler loading leading to higher strength. [ 10 ]…”