Mini Review - Advanced Materials Science Research (2022) Volume 5, Issue 4

Raman Spectroscopy as Spectral Tool for Assessing the Degree of Conversion after Curing of Two Resin-Based Materials Used in Restorative Dentistry

Dr. Satchidananda Rath*

Department of Material Science and Nano Material, India

*Corresponding Author:
Dr. Satchidananda Rath Department of Material Science and Nano Material, India E-mail:

Received: 01-Aug-2022, Manuscript No. aaamsr-22-72467; Editor assigned: 05-Aug-2022, Pre-QC No. aaamsr-22-72467 (PQ); Reviewed: 20-Aug-2022, QC No. aaamsr-22-72467; Revised: 24-Aug-2022, Manuscript No. aaamsr-22-72467 (R); Published: 30- Aug -2022;  DOI: 10.37532/ aaasmr.2022.5(3).66-69


The remedy of dental cavities and recuperation of teeth form calls for specialised substances with particular medical residences, which includes being smooth to model, light-cured, having a herbal colour, decreased shrinkage, a hardness much like hydroxyapatite, and no leakage. The dimensional balance of resin composite substances is stricken by polymerization shrinkage, diploma of conversion (quantity of π carbon bonds transformed into σ ones), thermal contraction and expansion, and interactions with an aqueous environment. The substances utilized in our research had been composite resins with comparable polymer matrices, however distinctive filler (micro/Nano filler). To compare the residences of samples, we hired the pycnometer technique (pycnometer from Paul Marienfeld Gmbh, Lauda-Königshofen, Germany), RAMAN spectroscopy technique, SEM and EDX The length of the filler performs an critical function with inside the polymerization: for the pycnometric results, the bigger particle filler appears to go through a speedy polymerization at some stage in the forty five s curing, whilst the nanoparticle filer desires extra curing time to completely polymerize. This is associated with a miles large porosity, as proved through SEM images. The decrease diploma of conversion, as received through Raman spectroscopy, with inside the equal geometry way that the equal quantity is probed for each samples because of this that much less quantity of polymer is probed for Sample.


Raman Spectrometry • Conversion Rate Resin-Based Composite • Dentistry Restoration


The remedy of dental cavities and healing of enamel form calls for specialised substances with precise medical residences, such as being clean to model, mild-cured, having a herbal colour, decreased shrinkage, a hardness much like hydroxyapatite, and no leakage. A unmarried particular fabric does now no longer own most of these residences however via way of means of combining an inorganic filler with a polymer matrix, one obtains a resin-primarily based totally fabric that has all of them. Thus, considering 1958, resin-primarily based totally composites had been an increasing number of used as dental restorative substances or dental cements, due to their suitable aesthetic and mechanical residences [1]. The first era of composites added with inside the medical exercise turned into with inside the Nineteen Eighties with Bis-GMA as a major component, observed with inside the Nineteen Nineties with the second one era of resin composites primarily based totally on polygalas substances. First-era composite resin substances are confined via way of means of 3 drawbacks: (1) unreacted monomer left after polymerization; (2) much less than top-quality hardness which limits the application, e.g., the fabric can't be used for all teeth, best for those that showcase decrease masticatory masses at some point of chewing; and (3) fatigue and cracking of the polymer because of shrinkage after polymerization. Among all, the maximum critical aspect is polymerization shrinkage that reasons marginal gaps among the tooth and resin and might cause untimely failure of the healing. Debonding can also additionally create plastic deformation, marginal leakage and staining, postoperative sensitivity, and boom the danger of secondary caries formation and pulpal inflammation. Polymerization shrinkage will affect the adhesion of the polymer–enamel interface, which is an inevitable impact of the curing technique as monomer molecules[2], transformed right into a cross linked polymer network, alternate van der Waals bonds for shorter covalent bonds. This volumetric shrinkage reasons pressure in restrained environments inclusive of enamel cavities.

Incorporation of filler into resin matrix substantially impacts and improves fabric residences, furnished that filler debris are bonded to polymer matrix or in any other case it can really weaken the resin. Thus, filler–polymer matrix coupling determines, to a massive extent, the mechanical power and medical toughness of dental composites. Several forms of filler are normally utilized in medical exercise, such as glass, pyrogenic silica, zirconia, natural filler metal/alloy and, lately, bioactive glass [3]. Despite the sort of formulations, the polymerization shrinkage following curing of the resin affords a prime problem. The toughness of the composite resin fabric is decided via way of means of the diploma of conversion. By reading the diploma of conversion, one should set up an immediate correlation among the first-class of polymerization and the hardness of the composite. Spectrometry is the primary approach to decide the residual monomers because of its sensitivity closer to conjugated structures [4].

Materials and Methods

The substances utilized in our research have been composite resins (RBC) with the identical polymer matrix (BIS-GMA, TEGDMA, BIS-EMA), however exclusive filler (micro/Nano filler) commercially to be had available in the marketplace in Romania. ValuxTMPlus Restorative 3M ESPE, a primary-era composite resin fabric which includes Bis-GMA and TEGDMA resins and 66% vol. zirconia/silica inorganic filler with a particle length variety of 3five to 0.01 micron. BrilliantTMNG Coltene, a second-era composite resin fabric that is a Nano composite with pre-polymerized particle filling with excessive Nano metric particle content. Sample 1 is available in five sun sunglasses to be had in four g syringes, even has a duo colouration device withinside the identical syringe simplifying the choice of colour and stock of syringes Both samples have warning signs for anterior and posterior restorations such as inlays, onlays, and veneers[5].

Small discs with a diameter of five mm and a thickness of one mm have been organized so as to research the density of the fabric. Curing turned into finished with an LED lamp (mild emitting diodes, λ = 420 ÷ 480 nm, Kerr Corp., Orange, CA, USA), with exclusive curing programs (variable mild depth, exclusive time costs and mixed). [6] As a primary step of the research, the variant withinside the density of the samples turned into tested earlier than and after curing (curing time forty five s) the usage of the Archimedes’ principle (pycnometer from Paul Marienfeld Gmbh, Lauda-Königshofen, Germany). Density correction for water turned into implemented to the consequences [7].

For the composite healing, the standardized mesio-occluso-distal (MOD) hollow space education turned into finished in an extracted top human premolar, the usage of a medium-grained diamond bur. The molar extraction turned into finished at some point of the complicated remedy of the top jaw, for a sinus raise augmentation of a affected person as reported. The identical bioethical approval turned into implemented. Sample 1 (ValuxTMPlus Restorative 3M ESPE) turned into incrementally implemented and mild-cured for 20 s from the LED mild-curing device, transferring output depth from 1.a hundred mW/cm2 to a top of one.330 mW/cm2 a couple of instances in the course of the curing cycle[8].

Raman spectroscopy assessment turned into finished with a BTR111—785 RAMAN spectrometer device (λ = 785 nm, output energy p = three hundred mW, and spectral decision four cm−1) withinside the Raman shift variety a hundred–2200 cm−1. The spectrometer is prepared with BAC101 immersion Raman probe, with the minimal spot length for excitation of a hundred µm at 0.five mm. The 785 nm laser energy used for all measurements turned into 30 mW (10% from three hundred mW to be had) which offers an irradiance of approximately 382 W/cm2. The laser spot and irradiance tiers have been saved regular at some point of Raman spectra acquisition. Energy Dispersive X-Ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM) have been finished in a Zeiss Evo 50 XVP microscope, at room temperature (RT), prepared with a secondary electron detector in low vacuum and a stable nation BSE detector, plus an auxiliary micro analytic SDD radiation detector[9] .

Raman Spectroscopy

Raman consequences display a comparable conduct for each samples 1 and 2, due to the fact each samples include comparable polymers. The essential variations seem because of the filler: for the micro composite (Figure 3a), bending of the ZrO bond seems at one thousand cm−1 and at 806 cm−1 for the bending of the Si2O; withinside the case of the Nano composite, there are low depth peaks at 806 cm−1 and 1200 cm−1 (related to the stretching of the SiO). Common peaks are related to exclusive vibrations of the carboxyl groups: at 1300 cm−1 (stretching of the C=O bond) [10], 1404 cm−1 (stretching of the C=CH2), 1446 cm−1 (stretching of the fragrant ring), 1609 cm−1 (skeletal vibration of the fragrant ring), 1640 cm−1 (stretching of the C=C bond in methacrylate), and 1714 cm−1 (stretching of the C=O bond). Comparing the spectra from uncured to forty five s curing, we will study versions concerning top intensities, which endorse the presence of unreacted monomer in each sample. Furthermore, thinking about that the spectra have been received from more or less the identical spot, the spectra do now no longer comply with a run of the mill fashion due to the fact a speedy saturation is predicted at the floor of the sample. Additionally, the variant of historical past is negligible evaluating to the outstanding Raman peaks [11].

Results and discussion

Following density measurements, an imaging research turned into finished the usage of SEM. The samples have been sectioned extensive and imaging turned into finished withinside the center of the section, however additionally at the aspect dealing with the curing lamp and the other aspect. The SEM micrographs display that the micro composite has a porous structure this porosity being maintained on each the aspect dealing with the curing lamp and the other aspect The Nano composite indicates an extra compact floor, with uncommon and high-quality pores 1d). However, there are massive holes at the aspect dealing with the curing lamp even as the compactness of the returned aspect floor is evident [12-14].


Two forms of composites have been studied and the diploma of curing turned into assessed. The consequences from the pycnometric records appear to finish that Sample 1 (microcomposite) has a diploma of conversion better than Sample 2 (nanocomposite). The SEM and EDX micrographs confirmed that Sample 1 has a porous floor even as Sample 2 affords with an extra compact floor, even though now no longer absolutely without holes. The elemental dispersion for the enamel healing confirmed that an awesome bonding is received on the tooth–resin interface due to its essential inorganic structure; even as a brand new form of bonding is needed for the dentin–resin interface (the polymer is inclined on the dentin–composite interface). Both samples have the identical variant in density at some point of polymerization (~21%). The density distinction comes from fillers, as Sample 1 carries ZrO2/SiO2 as opposed to SiO2 best for (ZrO2 density is five. Sixty eight g/cm3 even as SiO2 density is 2[15,16]. After calculating Vinitial–Final, we received a distinction of five.375 mm3 for Sample 1 and four.375 mm3 for. The large boom of the extent for Sample 1 is associated with a miles large porosity as proved via way of means of SEM images. This reasoning additionally explains the decrease diploma of conversion as received via way of means of Raman spectroscopy withinside the identical geometry. This method that the identical extent is probed for each sample however is extra porous, because of this that much less quantity of polymer is probed. Further investigations are vital to evaluate the have an impact on of water and nitrogen upon shrinkage and conversion rate.


  1. Dworak S,  Rechberger  H,  Fellner  J. How will tramp elements affect future steel recycling in Europe? A dynamic material flow model for steel in the EU-28 for the period 1910 to 2050.Resour Conserv Recycl. 179, 106072 (2021).
  2. Google Scholar, Crossref

  3. Dworak S, Fellner J. Steel scrap generation in the EU-28 since 1946—Sources and composition.Resour Conserv Recycl.2021,173, 105692 (2021).
  4. Google Scholar, Crossref

  5. Eder W. Environment-Climate-Energy: Quo Vadis, Industry?BHM Berg-Hüttenmännische Mon.162, 494–497 (2017).

    Google Scholar, Crossref

  6. Griesser A,  Buergler T. Use of HBI in Blast Furnace.BHM Berg-Hüttenmännische Mon.164, 267–273 (2019).
  7. Google Scholar, Crossref

  8. Spreitzer D,  Schenk J. Reduction of Iron Oxides with Hydrogen—A Review.Steel Res Int.90, 1900108 (2019).
  9. Google Scholar, Crossref

  10. Jiang X, Wang L, Shen FM. Shaft Furnace Direct Reduction Technology—Midrex and Energiron.AMR805–806, 654–659 (2013).
  11. Google Scholar, Crossref

  12. Sarkar S, Bhattacharya R, Roy GG et al. Modeling MIDREX Based Process Configurations for Energy and Emission Analysis.Steel Res Int. 89, 1700248 (2018).
  13. Google Scholar, Crossref

  14. Shams A, Moazeni F. Modeling and Simulation of the MIDREX Shaft Furnace: Reduction, Transition and Cooling Zones.JOM67, 2681–2689 (2015).
  15. Google Scholar, Crossref

  16. Elmquist  SA, Weber P, Eichberger  H. Operational results of the Circored fine ore direct reduction plant in Trinidad.Stahl Eisen.122, 59–64 (2002).
  17. Google Scholar

  18. Linklater J. Adapting to Raw Materials Challenges—Part 2: Operating MIDREX Plants with Lower Grade Pellets & Lump Ores.Direct Midrex4/2021, 3–8 (2021).
  19. Google Scholar

  20. Linklater J. Adapting to Raw Materials Challenges—Part 1: Operating Midrex Plants with lower grade Pellets and Lump Ores.Direct Midrex1/2021, 3–7 (2021).
  21. Google Scholar

  22. Cardenas  JGG, Conejo  AN,  Gnechi GG. Optimization of energy consumption in electric arc furnaces operated with 100% DRI.Metal2007, 1–7 (2007).
  23. Google Scholar

  24. Kirschen M,  Badr  K,  Pfeifer H. Influence of direct reduced iron on the energy balance of the electric arc furnace in steel industry.Energy.36, 6146–6155 (2011).
  25. Google Scholar, Crossref

  26. Lule R, Lopez F, Espinoza J et al. The Experience of ArcelorMittal Lázaro Cardenas Flat Carbon.Direct Midrex.3-4/2009, 3–8 (2009).
  27. Google Scholar

  28. Al Dhaeri A, Razza P, Patrizio D. Excelent operating results of the integrated minimill #1 at Emirates Steel Industries: Danieli.Metall Plant Technol Int.33, 34 (2010).
  29. Google Scholar