Evaluation of Color Stability of Composite Resin Used to Characterize Acrylic Teeth—An In Vitro Study

Round 1

Reviewer 1 Report

Dear Authors,

generally, the write-up of the paper is good. Here are some suggestions to improve the manuscript.

 

The authors shall use fewer paragraphs. The authors too often go to the next line. Please use a new paragraph only when the topic changes.

 

National Bureau of Standards (NBS) system of expressing color differences is not a standard in dental color change.

 

The authors shall consider clinical thresholds: 

Paravina RD, Pérez MM, Ghinea R. Acceptability and perceptibility thresholds in dentistry: A comprehensive review of clinical and research applications. J Esthet Restor Dent. 2019 Mar;31(2):103-112. doi: 10.1111/jerd.12465. Epub 2019 Mar 20. PMID: 30891913.

 

Clinical thresholds are important, and if a resin changes color but is within the acceptability threshold, it is not clinically relevant (it is not a problem). But if a resin is stained MORE than another (significant difference) but both their DeltaE is higher than the clinical thresholds, they BOTH have clinically unacceptable results.

 

The authors could draw on the Graphs the lines of perceptibility and acceptability thresholds (1.2 and 2.7 for example or the thresholds for CIELAB) so the reader can easily correlate the height of the histogram bars with the clinical thresholds.

 

Line 115: please report radiance of the light in mw/cm2

 

Line 140: please report type of toothpaste and level of abrasivity

 

Lines 380-2: 

The authors wrote: “Low pH media like cola (pH 2.7) have been proven to influence the surface integrity of materials like resins by softening the matrix and triggering a loss of structural ions from the glass phase, including calcium, aluminum, silicone, and other elements. “

Please support this sentence with a proper reference. The author could cite :Paolone G, Formiga S, De Palma F, Abbruzzese L, Chirico L, Scolavino S, Goracci C, Cantatore G, Vichi A. Color stability of resin-based composites: Staining procedures with liquids-A narrative review. J Esthet Restor Dent. 2022 Sep;34(6):865-887. doi: 10.1111/jerd.12912. Epub 2022 Apr 9. PMID: 35396818.

The mentioned article clearly speculates the staining dynamics of several liquid colorants, including Cola.

 

 

Conclusions:

The authors could give the Conclusions a bullet point format and reduce the length. Example:

SR Nexco paste (Den- 397 

tin, Incisal and Gingiva) on exposure to coffee underwent a statistically significant color change. SR 398 Nexco paste (Dentin, Incisal and Gingiva) on exposure to turmeric underwent statistically significant 399 color change.SR Nexco paste (Dentin, Incisal and Gingiva) on exposure to Coca Cola underwent 400 statistically significant color changes. 

 

Could be summarized in:

Statistically, significant color change was reported for SR Nexco paste (Dentin, Incisal and Gingiva) exposed to coffee, turmeric, and cola.

etc.

Author Response

Comments and Suggestions for Authors

Dear Authors,

generally, the write-up of the paper is good. Here are some suggestions to improve the manuscript.

 

The authors shall use fewer paragraphs. The authors too often go to the next line. Please use a new paragraph only when the topic changes.

 

National Bureau of Standards (NBS) system of expressing color differences is not a standard in dental color change.

 

The authors shall consider clinical thresholds: 

Paravina RD, Pérez MM, Ghinea R. Acceptability and perceptibility thresholds in dentistry: A comprehensive review of clinical and research applications. J Esthet Restor Dent. 2019 Mar;31(2):103-112. doi: 10.1111/jerd.12465. Epub 2019 Mar 20. PMID: 30891913.

 

Clinical thresholds are important, and if a resin changes color but is within the acceptability threshold, it is not clinically relevant (it is not a problem). But if a resin is stained MORE than another (significant difference) but both their DeltaE is higher than the clinical thresholds, they BOTH have clinically unacceptable results.

 

The authors could draw on the Graphs the lines of perceptibility and acceptability thresholds (1.2 and 2.7 for example or the thresholds for CIELAB) so the reader can easily correlate the height of the histogram bars with the clinical thresholds.

 

Reply: Thank you for your valuable comments and suggestion for updating us regarding clinical thresholds:

In our study we chose NBS system for expressing the color differences and the reason as follows:

 

Colors are determined and measured in dental settings using two broad approaches – instrumental and visual. Instrumental calorimetric determinations are more reliable means of preventing subjective errors arising during color assessments. In our study spectrophotometer (X- Rite i1 Eye- One Pro Rev D Spectrophotometer, Althardstrasse, Regensdorf, Switzerland) was used to quantify the color of each specimen using NBS units.

Although there are studies using different criterias for perception of color values, our study uses NBS system to determine the degree of color differences it offers absolute criteria by which color values can be converted to definitions with clinical significance thus relating the changes to clinical environment. NBS system plays an important role in quality control and color comparison functions. Our study revealed statistically significant color variations among the specimens in staining agents used.

Because visual color assessment is subjective, the color systems are quantitative systems with rectangular co-ordinates that allow an objective color measurement. Hence this system was used in our study as it adequately represents the visual perception of color differences with standardized values suggested by Koksal and Dikbas. This system is widely used for measurement of colour stability under esthetic zones.

 

 

Line 115: please report radiance of the light in mw/cm2

 

Reply : LED light curing (Guilin Woodpecker Medical Instrument Co. Ltd, Guilin, Guangxi, China) was used in this study. The light intensity of this LED light curing unit is 850mW/cm² – 1000mW/cm² (as per user manual)

 

 

Line 140: please report type of toothpaste and level of abrasivity

 

Reply : The Toothpaste used in this study was Colgate Total (Colgate Palmolive Ltd, India). According to ISO specification a toothpaste should not exceed RDA (Relative Dentin Abrasiveness) value of 250 which is considered as a safe limit for hard tissues. Hence the toothpaste used in the present study was Colgate Total whose RDA value was 70.

 

 

 

Lines 380-2: 

The authors wrote: “Low pH media like cola (pH 2.7) have been proven to influence the surface integrity of materials like resins by softening the matrix and triggering a loss of structural ions from the glass phase, including calcium, aluminum, silicone, and other elements. “

Please support this sentence with a proper reference. The author could cite :Paolone G, Formiga S, De Palma F, Abbruzzese L, Chirico L, Scolavino S, Goracci C, Cantatore G, Vichi A. Color stability of resin-based composites: Staining procedures with liquids-A narrative review. J Esthet Restor Dent. 2022 Sep;34(6):865-887. doi: 10.1111/jerd.12912. Epub 2022 Apr 9. PMID: 35396818.

The mentioned article clearly speculates the staining dynamics of several liquid colorants, including Cola.

 

Reply : Added under references and cited under line 382 as no 35 reference

 

 

Conclusions:

The authors could give the Conclusions a bullet point format and reduce the length. Example:

SR Nexco paste (Den- 397 

tin, Incisal and Gingiva) on exposure to coffee underwent a statistically significant color change. SR 398 Nexco paste (Dentin, Incisal and Gingiva) on exposure to turmeric underwent statistically significant 399 color change.SR Nexco paste (Dentin, Incisal and Gingiva) on exposure to Coca Cola underwent 400 statistically significant color changes. 

 

Could be summarized in:

Statistically, significant color change was reported for SR Nexco paste (Dentin, Incisal and Gingiva) exposed to coffee, turmeric, and cola.

etc.

 

Reply : conclusion modified with bullet point format

Author Response File: Author Response.docx

Reviewer 2 Report

1. What is the primary objective addressed by the research?

2. What is the novelty of your manuscript? Please explain in this manuscript.

3. What applications does this method have?

4. Please add a schematic in the introduction to define your work.

5. Please add a more discussion and conclusion section.

6. Please add the appropriate references to your manuscript.

Author Response

Comments and Suggestions for Authors

1. What is the primary objective addressed by the research?

 

Reply: added under introduction line 101 - 107

Primary objective of our study is to address the esthetic considerations and color accuracy and durability. One of the most important features of restorative dental materials is color stability and any changes under color stability indicate aging or damaged materials.

Methods for determining color stability- manual(visual) and instrumental (hardware) visual assessment is quite subjective and arises the need for quantitative analysis of the data which was done by color calibration using spectrophotometer

 

2. What is the novelty of your manuscript? Please explain in this manuscript.

 

Reply : added under discussion line 434

 

Evaluating long-term consequences of aging and staining are required with introduction of newer composite SR Nexco paste (Ivoclar). There was no evidence in literature about the color stability of layering materials ( Incisal, Dentine and Gingiva) of this newer composite. Knowing the color stability of SR Nexco paste indirect composite helps us to know the durability and acceptability of artificial teeth on which the composite is used to layer the acrylic teeth.

 

3. What applications does this method have?

                                    

Reply : added under discussion line 440

 

 The main application of this novel method helps the clinician to evaluate the color stability of different layering materials of laboratory processed composite resin which is used for characterizing acrylic denture teeth. This latter method using indirect composite material will produce more lifelike appearance of acrylic teeth over the denture base in edentulous patients.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4. Please add a schematic in the introduction to define your work.

 

 

                                  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5. Please add a more discussion and conclusion section.

 

Reply :

 

Discussion:

 

1. Alhotan A (2022) investigated on effect of different solutions on color stability of nano particle or fiber reinforced PMMA using NBS system showed significant different color changes between all tested groups ( ZrO₂ nanoparticles, E-glass fibres and TiO₂ nanoparticles) and across different time points. In this study, coffee appeared to have the extreme influence on the CF (coffee) change in comparison to the denture cleaner STD(Steradent)/CF. TiO2 reinforced PMMA in coffee showed lowest color stability, while the E-glass fiber reinforced PMMA in STD/CF showed highest color stability.

 

2. Alshehri A(2022) compared the color stability and surface roughness of conventional and self-blending resin composites before and after staining and aging. Composites used in the study were three conventional composites( Filtek Z350, IPS Empress Direct,and Estalite Palfique LX5) and one self-bending composites(Omnichroma). All groups showed significant decrease in all color parameters( L*,a*,and b*) and after polishing all groups showed enhancement in color, thus matching pre experiment baseline colors.

 

3. Kammath SK (2021) comparatively evaluated the effect of three different beverages ( Dasamoolaristam an ayurvedic medicine,tea,grape juice and distilled water) on color stability of two brands of acrylic denture teeth( Acryrock and Rolex) exposed to four immersion times . A1 shade maxillary right central incisors of two brands were used. The study showed maximum color change on exposure to Dasamoolaristam for rolex teeth set. Highest color mean difference was obtained in the Dasamoolaristam on day 30 of measurement of the rolex teeth set.

 

4. Altiparmak ET (2022) observed the color change of cold beverages consumed on resin containing restorative materials. There was no statistically significant difference in color changes of the resin containing dental materials at the end of 1^st day (p>0.05) but, at the end of 7^th and 30^th day, cold tea caused statistically higher color change (p<0.05). composite resins showed more color change than resin based CAD/CAM blocks.

 

5. Alfouzan AF (2021) evaluated and compared the color stability of 3D printed and conventional heat polymerized acrylic resins following aging, mechanical brushing and immersion in staining medium. The autonomous factors, namely material, staining medium and immersion time, and interaction among these factors significantly influenced ∆E (p<0.001). Irrespective of the materials, treatments and time, the highest and the lowest mean ∆Es were observed for PMMA( poly methyl methacrylate) in lemon juice and DB (3D printed DentaBASE) in artificial saliva.

 

Conclusion:

Physical appearances of denture teeth mainly rely on its glossy presence with color durability. The loss of surface gloss suggests increase in the color change value. Full or partial removable dentures with an impressive natural appreance can be produced by individual characterization of prefabricated prosthetic teeth. Characterization of complete is necessary to give the dentures a life like appearance, to make it look more natural.

6. Please add the appropriate references to your manuscript.

Reply : following references were included in the manuscript

1. Paolone G. Color stability of resin-based composites: Staining procedures with liquids-A narrative review. J Esthet Restor Dent 2022;34(6):865-887.

 

2. Alhotan A. Effect of different soluions on the colour stability of nanoparticles or fibre reinforced PMMA. Polymers 2022;14(1521):1-14.

 

3. Alshehri A. Effect of accelerated aging on color stability and surface roughness of a biomimetic composite: An In vitro Study. Biomimetics 2022;7(158):1-11.

 

4. Kammath SK. Comparative evaluation of effect of three beverages on color stability of two brands of acrylic denture teeth: An In vitro study. Dent Med Res 2021;9:107-15.

 

5. Altiparmak ET. The effect of cold drinks on the coloration of resin-containing restorative materials. Int Dent Res 2022;12(1):14-20.

 

6. Afnan Fouzan Alfouzan. Color stability of 3D- printed denture resins: effect of aging, mechanical brushing, and immersion in staining medium. J Adv Prosthodont 2021;13:160-71.

 

 

 

 

Author Response File: Author Response.docx

Reviewer 3 Report

The author should reorganise all data in proper research articles the present manuscript seems like a lab record book, please refer to some research articles that follows the way of presentation and don't put unnecessary images such as incubator and all.

 

Author Response

Comments and Suggestions for Authors

The author should reorganise all data in proper research articles the present manuscript seems like a lab record book, please refer to some research articles that follows the way of presentation and don't put unnecessary images such as incubator and all.

 Reply : Thank you and Noted your valuable suggestion 

Author Response File: Author Response.docx

Reviewer 4 Report

The authors clearly described specific examples of the influence of food products on the color of dental polyacrylates. The results are clearly described. The conclusions are of practical importance. In conclusion, it is worth noting that there is a large area of research in the field of modification of this type of dental materials from the point of view of reducing susceptibility to color change. This applies to both the composition of the material and its cross-linking. The latter process is also important from the point of view of the effect of monomer residues on the patient.

The change in color, apart from specific food additives, is also associated with a change in the condition of the polymer surface as a result of degradation. Specifically, oxidation processes. These can be tested with the DRS (Diffuse Reflectance Spectroscopy). In this case, the reflected radiation is cut off and the light scattered by the near-surface layers of the material is analyzed. Scattered light It carries information about degradation products.

file:///C:/Users/w.gluszewski/Downloads/Radiation%20effects%20in%20polypropylene%20(5).pdf

By the way, it would be useful to describe how the possible radiation cross-linking affects the color change of the dental material. In addition to changing the material properties, it is also possible to crosslink the residual monomer.

Author Response

Comments and Suggestions for Authors

The authors clearly described specific examples of the influence of food products on the color of dental polyacrylates. The results are clearly described. The conclusions are of practical importance. In conclusion, it is worth noting that there is a large area of research in the field of modification of this type of dental materials from the point of view of reducing susceptibility to color change. This applies to both the composition of the material and its cross-linking. The latter process is also important from the point of view of the effect of monomer residues on the patient.

The change in color, apart from specific food additives, is also associated with a change in the condition of the polymer surface as a result of degradation. Specifically, oxidation processes. These can be tested with the DRS (Diffuse Reflectance Spectroscopy). In this case, the reflected radiation is cut off and the light scattered by the near-surface layers of the material is analyzed. Scattered light It carries information about degradation products.

file:///C:/Users/w.gluszewski/Downloads/Radiation%20effects%20in%20polypropylene%20(5).pdf

By the way, it would be useful to describe how the possible radiation cross-linking affects the color change of the dental material. In addition to changing the material properties, it is also possible to crosslink the residual monomer.

Reply : Thank you for your valuable information and we shall note these points and bring the best in our future research topics following this methodology.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have amended all the requests

Author Response

The authors have amended all the requests

Thank you so much for your valuable time and consideration

 

Reviewer 3 Report

The Manuscript has not been compiled into a proper form research article 

the results and discussion have not been arranged properly author should arrange the manuscript in proper research articles formate.

Author Response

Dear Reviewer, Thank you for your valuable time and consideration.

Comments:

1. The Manuscript has not been compiled into a proper form research article 

       Reply – Thank you for insightful suggestions and comments. The revised             manuscript  compiled into a research article form.

2. the results and discussion have not been arranged properly author should arrange the manuscript in proper research articles format.

         Reply- results and discussion rearranged and properly written as per your             insightful suggestions and comments.

Best regards