Preparation and evaluation of (R)-(-)-carvone-doped polymeric resins as potential antibacterial dental materials.

OBJECTIVES: This study aimed to develop and evaluate resin-based antibacterial materials incorporating carvone for restorative dentistry. The objectives included assessing antimicrobial activity, conversion degree, mechanical properties, hydrolytic and hygroscopic behavior, cytotoxicity, among others. METHODOLOGY: Carvone was incorporated into resin-based materials following established protocols. Antimicrobial activity was evaluated against S. Aureus. Conversion degree, polimerization kinetics, mechanical properties, hydrolytic and hygroscopic behavior, cytotoxicity, and other properties were assessed using standardized tests and methodologies. RESULTS: Carvone-incorporated materials demonstrated significant antimicrobial activity, minimal changes in conversion degree, comparable mechanical properties, improved hydrolytic and hygroscopic behavior, and lack of cytotoxicity. Antimicrobial resins were obtained due to the hydrophobic nature of carvone and its ability to diffuse through the cell walls of microorganisms, causing membrane damage. The polymerization process yielded successful conversion, ensuring adequate material performance. SIGNIFICANCE: This study showcases that incorporating carvone into methacrylate-based resins can confer antimicrobial properties while preserving key material attributes. Antimicrobial activity against S. aureus is achieved without cytotoxicity in human fibroblasts. While flexural properties are affected only at carvone concentrations exceeding 9%, conversion degree and polymerization kinetics remain stable, except for a specific experimental formulation. These findings highlight the balanced integration of carvone. However, further work, including assessing antimicrobial performance against specific strains like S. Mutans and/or C. Albicans, and evaluating long-term effectiveness, is essential to establish the potential of these materials for dental restorations.

Photopolymerizable dental composite resins with lower shrinkage stress and improved hydrolytic and hygroscopic behavior with a urethane monomer used as an additive.

This work reports the synthesis of a monomer 2-((2-(3-(prop-1-en-2-yl)phenyl)propan-2-yl)carbamoyl)oxy)ethyl methacrylate (MVTPM) and the evaluation of its performance as an additive in the formulation of Bis-GMA/TEGDMA based composite resins. Experimental composite resins formulated with the MVTPM monomer were compared with a control reference. Double bond conversion, polymerization kinetics, shrinkage and associated stress, sorption, and aqueous solubility, cell viability, as well as mechanical properties were evaluated according to international measurements standards. The experimental composite resins show comparable mechanical properties with the control reference and improvements in other properties, such as better hydrolytic and hygroscopic behavior and lower shrinkage stress, are reported. This makes MVTPM monomer potentially useful in the formulation of dental composite resins.

Dental composite resins with low polymerization stress based on a new allyl carbonate monomer.

The objective of this study was to synthesize a diallyl carbonate monomer, allyl(2-(2-(((allyloxy)carbonyl)oxy)benzoyl)-5-methoxyphenyl) carbonate (BZ-AL), and to evaluate its effect as Bis-GMA diluent in the formulation of photopolymerizable dental composite resins. The chemical structure of BZ-AL monomer was determined by means of H1 NMR, C13 NMR and FTIR spectroscopies. An experimental composite comprising a mixture of Bis-GMA and BZ-AL monomers and silanized inorganic filler was formulated. Experimental material was compared with a control composite formulated with Bis-GMA/TEGDMA. Double bond conversion, polymerization kinetics, volumetric shrinkage, polymerization stress, and flexural properties were investigated. The data were analyzed through a Student t-test (α = 0.05). Flexural strength of the experimental materials with BZ-AL monomer showed a statistically significant increase (p < 0.001). The experimental composite has a lower polymerization rate than the control composite, on the other hand, the experimental composite resin has the highest degree of double bond conversion. There are no differences in the polymerization shrinkage of the composites, however, the polymerization stress of the experimental materials was 50% lower than the control resin. Finally, the cell viability test showed that the experimental resins formulated with the BZ-AL monomer was not cytotoxic. Due to its characteristics, BZ-AL monomer is potentially useful for the formulation of composite materials with applications in dentistry.

Preparation and evaluation of a BisGMA-free dental composite resin based on a novel trimethacrylate monomer.

OBJECTIVE: The use of the BisGMA as base monomer in dental composites has been questioned because of bisphenol A (BPA) is used as raw material in its synthesis, and BPA possess estrogenic potential associated to several health problems. This study describes the synthesis of the trimethacrylate tris(4-hydroxyphenyl)methane triglycidyl methacrylate (TTM) monomer and evaluate its effect when used as base monomer in the formulation of experimental photopolymerizable composite resins. METHODS: The TTM monomer was synthesized by a nucleophilic acyl substitution. Its chemical structure was confirmed via 1H and 13C NMR spectroscopy and FTIR spectroscopy. Experimental composite resins were formulated by mixing TTM, triethyleneglycol dimethacrylate (TEGDMA) and inorganic fillers. A BisGMA/TEGDMA based composite resin was prepared and used as control to compare several physicochemical properties. Cell viability assay was used for cytotoxicity evaluation. RESULTS: TTM was successfully synthesized with quantitative yields. The results showed that the TTM-based composite resin had similar values of flexural strength, elastic modulus, degree of conversion and polymerization shrinkage than the control (p > 0.05). Water sorption and solubility were statistically significantly higher than the control (p < 0.05), however they complied the requirements stablished by the ISO 4049. Finally, this study shows there were no statistically significant differences for the biocompatibility outcomes (p = 0.345). SIGNIFICANCE: TTM monomer could be potentially useful in the formulation of BisGMA free composite resins, which could mean to minimize the human exposure to BPA.

Evaluation of dental composites resins formulated with non-toxic monomers derived from catechol.

Two liquid monomers (CT-AL and CT-ACR) were synthesized from the acylation of tert-butyl catechol with different acid chlorides. The monomers were used to prepare photopolymerizable dental composite for completely replacing TEGDMA. Properties such as flexural strength, modulus of elasticity, degree of double bond conversion, polymerization shrinkage, as well as the polymerization stress were studied. Also, color alteration, translucency, and cytotoxicity were evaluated. The results show that the experimental materials formulated with CT-AL and CT-ACR have similar mechanical properties to a control material formulated with BisGMA/TEGDMA, similar polymerization shrinkage, and less polymerization stress. The composite formulated with the CT-AL monomer shows a similar degree of conversion (72%), while the composite formulated with the CT-ACR monomer has a degree of conversion lower (58%) than the control resin (71%). These results suggest that both monomers could have potential applications in the formulation of composites for dental restorations.