Composite resin is dental fillings widely used currently because they have a better aesthetic compared to other fillings.听Composite resins bind to the tooth structure through adhesive material, called dentin bonding.听Various dentin bonding materials mostly still use the basic ingredient2-hydroxyethyl methacrylate(HEMA).听HEMA is widely used because it has excellent physical-chemical properties, that is stable, both as a basic material for bonding and when mixed with other ingredients.听However, HEMA also has a weakness from its toxicity.听Besides HEMA, additional composition of dentin bonding is the addition of a solvent in the form of ethanol or water which functions as a monomer conduit to minimize the toxic effects of the monomer, HEMA.
Cytotoxic activity of chemical compounds can be observed from the ability of these chemical compounds to stimulate cell death (apoptosis).听Apoptosis is programmed cell death, it is active, and it requires energy and is not accompanied by inflammation.听HEMA monomers are toxic to cells because they contain hydroxyl groups (-OH), as a result of monomers that are not fully polymerized to produce residual monomers.听The hydroxyl group is a free radical molecule.听The hydroxyl group can induce the production ofReactive Oxygen Species(ROS) in fibroblast cells which causes DNA fragmentation and imbalance in cell homeostasis, resulting in inflammation and delays in the cell cycle, which then result in cell death.
Pulp fibroblast cells are the most significant component of dental pulp, periodontal ligament, and gingiva.听Based on the research result on the culture of fibroblast cells isolated from human M3 dental pulp had been extracted using a trypsinization method.听Cells were divided into four groups, untreated fibroblast cell culture, fibroblast cell culture with the addition ofchitosan scaffold, fibroblast cell culture withchitosan scaffoldwhich was given dentin bonding with ethanol solvent, and fibroblast cell culture withchitosan scaffold which was given dentin bonding with water solvent, each polymerized using a light-curing unit.听Then placed in fibroblast cell culture, and followed by apoptosis test with immunocytochemical methods using staining Ethidium Bromide Acridine Orange and examined using a 40x magnification fluorescent microscope.
Based on observations using a fluorescent microscope, a picture of the culture of pulp fibroblasts in each treatment group was acquired and it was found that thechitosan scaffoldcontrol groupshowed that the pulp fibroblast cells had apoptosis by 0.9%, the pulp fibroblast cell culture group with HEMA dentin bonding and addition of ethanol-solvent had an apoptosis rate of 67%, and pulp fibroblast cell culture with the addition of water-solvent for dentin bonding HEMA had an apoptosis rate of 44%.
The average value of apoptosis of pulp fibroblast cells with HEMA dentin bonding and ethanol solvent was higher than apoptosis of pulp fibroblast cell apoptosis by the administration of water-solvent dentin bonding HEMA.听It happens because the ethanol solvent has physical properties ofH-bondingcapacityof 19.4 J / cm3smaller than the size ofH-bondingwater solvents, which is equal to 42.3 J / cm3.听It affects the binding of free radicals byH-bonding so that they can bind more free radicals.
Other physical properties possessed by ethanol solvents are surface tension of 22.27 dyn / cm, water solvent of 72.8 dyn / cm.听The lower the surface tension of the solvent, the easier it is to penetrate a cell surface layer so that monomers can diffuse into more cells and can induce oxidative stress and cytotoxicity in pulp cells.听HEMA can induce apoptosisin vitroafter 24 hours.听Apoptosis induced by monomers is the response of active cells to levels of ROS (Reactive Oxygen Species) that exceed the ability of cells to maintain cell homeostasis.
Whereas to determine the degree of apoptosis from pulp fibroblast cells after exposure to ethanol and water-solvent HEMA, a pairwise comparison statistical test was used.听The results showed that cell culture undergoing apoptosis between ethanol-solvent dentin bonding and water did not differ significantly which meant that there was no difference in apoptosis between pulp fibroblast cells and administration HEMA dentin bonding with ethanol and water as a solution.
Based on the results of the study it was concluded that the function of water and ethanol solvents could reduce the toxicity of HEMA bonding ingredients well so that it can be considered by dentists to choose bonding materials in treating dental fillings with composite resins.
Author: Ira Widjiastuti
Details of this research can be viewed in our work at:
Ira Widjiastuti, Ratih ElisaNandarani dan LatiefMooduto. Pulp Fibroblast Cell Apoptosis After Application of Hema Dentine Bonding Material with Ethanol and Water Solvent. Brazilian Dental Journal, 30(3):208:212; http://dx.doi.org/10.1590/0103-6440201902524
