[version 1; peer review: 1 approved with reservations]
No competing interests were disclosed.
The aim was the evaluation and comparison the bonding of the total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride using the universal testing machine and scanning electron microscope.
30 extracted teeth samples had been randomly distributed into 2 groups (n=15). The test group received the intervention of 38% SDF whereas the control group did not. Samples in both groups were restored with resin composite. Assessment The primary outcome will be determined by microtensile bond strength whereas the secondary outcome will be determined by fracture modes, i.e., cohesive, adhesive, or mixed fracture. Descriptive statistics will be used for the results of each group. Intergroup comparison will be done on the basis of independent sample t-test to detect the mean difference between the two groups. Independent t-test will be run to analyse the type of failure. In all tests, p-values below 0.05 will be considered statistically significant.
The study may provide us with a new restorative technique that will not only be less invasive by preserving the remaining tooth structure but will also prevent the risk of caries progression beneath the restoration. Thus, this will contribute to the longevity of the tooth life by the maintenance of its pulpal health which will contribute to the durability and long-term successful outcome of the direct restoration procedure.
The conventional treatment of a carious tooth is the complete removal of carious dentin followed by its restoration. However, authors like Yoshiyama
With total-etch adhesives, there may be a possibility of bonding and sealing of vital carious dentin. This isolates the remaining bacteria from any refined carbohydrates that exist in the saliva.
But there is a possibility that the residual active bacteria may provide antigens to the pulpal chamber and cause induction of cytokine reactions, which may lead to chronic pulp inflammation. So, there is a need to search for a material that can be used underneath the final restorative material which would make these viable bacteria dormant for arresting the caries progression.
38% Silver Diamine Fluoride (SDF) is one such material that has an antibacterial effect on carious dentin. It inhibits the bacterial enzyme collagenase and trypsin, thus making the remaining bacteria ineffective in carious dentin, which in turn inhibits caries progression.
However, to date, no research is available which has evaluated the effect of 38% SDF on carious dentin when used beneath total-etch adhesive followed by restoration with resin composite. In order to validate its use, it is most important to first establish the effect it may have on the bonding of the total-etch adhesive to carious dentin.
To understand this effect, we must first evaluate the microtensile bond strength (μTBS) of the total-etch adhesive to carious dentin when treated with 38% SDF. So, the research question here is that does total etch adhesive show similar microtensile bond strength to carious dentin in molars when treated with and without 38% silver diamine fluoride.
The null hypothesis is that total etch adhesive does not show similar microtensile bond strength to carious dentin in molars when treated with and without 38% silver diamine fluoride.
The alternate hypothesis is that the Total etch adhesive shows similar μTBS to carious dentin in molars when treated with and without 38% silver diamine fluoride.
To evaluate and compare the bonding of total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride using the universal testing machine (UTM) and scanning electron microscope (SEM).
To evaluat
To evaluate the μTBS of total-etch adhesive to carious dentin in molars treated
To compare the μTBS of total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride using the UTM.
To observe the type of fracture (adhesive/cohesive/mixed) at the bonding site of total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride using the scanning electron microscope.
This is an experimental in-vitro study which will have a test group (Group 1) and a control group (Group 2). The test group will receive the intervention of 38% SDF whereas the control group will not receive any such intervention. The allocation ratio will be 1:1. The allocation of the tooth samples to the two groups will be done by computer generated randomization.
The experimental study will be performed in the freshly extracted teeth samples in the Department of Conservative Dentistry and Endodontics, SPDC, DMIHER, Sawangi (M), Wardha over the period of 4 months. The study received its approval from the Institutional Ethics Committee of Datta Meghe Institute of Higher Education and Research (DU) [Ref No.- DMIHER (DU)/IEC/2023/649]. The study will be carried out on those tooth samples only which will be indicated for extraction and will be extracted after receiving written informed consent from those patients. Since the study will be undertaken in extracted molars of humans, it will not involve any major risk to human life.
Based on previous study,
The estimated sample size is 30, i.e., 15 in each group.
Extracted human permanent molars with fully developed root apices. Carious teeth with ICDAS (International Caries Detection and Assessment System) score of 4, 5, or 6.
Deciduous molars Molars without visible carious involvement in dentin (ICDAS score of 1,2,3). Teeth with fluorosis, restoration or fracture.
Extracted permanent molars will be collected and stored in 0.9% Saline (Abaris, India). Scaling of the teeth will be undertaken before the intervention using ultrasonic scaler tips (Woodpecker Scaler Tips, China). All the samples will be mounted in self-curing acrylic resin (DPI, India) by embedding their radicular portion in it whereas the coronal portion will remain exposed. The entire procedure will be carried out under the Dental Operating Microscope (DOM) (ZEISS OPMI pico, Germany). Superficial dentin will be removed using air-rotor (NSK, Japan) and round bur-BR-41 (Mani Inc, Japan). The samples will be examined under the DOM at 8.5× magnification to remove any defective, hypoplastic or cracked specimen. 1-2 drops of 38% silver diamine fluoride (SDF) solution will be dispensed in a mixing well. In
The final restoration in both the groups will be carried out at 5.1X magnification. Here, the surface etching is done with 37% phosphoric acid (Prime Dental Etching Gel Etchant, India) for 15 s and then will be washed with distilled water for the next 10 s. A total-etch adhesive bonding agent (3M ESPE Adper Single Bond 2 Refill Bonding Agent, United States) will be applied for 20 s and be lightly blown with compressed air for 5 s to create a thin uniform layer of material. This will then be cured for the next 20 s.
Each tooth sample will be vertically sectioned through the resin composite and dentin into 1 mm × 1mm-thick serial slabs using diamond disk (0.2 mm thickness and 20 mm diameter).
The sections will be examined under a stereomicroscope (ZEISS Stemi DV4, Germany) for the presence of fracture or failure of bond at resin-tooth interface, and hence will be discarded.
Those specimens having intact bonded interface will be subjected to microtensile bond strength (μTBS) evaluation. The section will be secured to the tester jaw using Cyanoacrylate (Zapit, CA, USA). Specimens will be then stressed to failure under tension by means of a UTM (ACME Engineers, India. Model No. UNITEST-10) at a crosshead speed of 1 mm per min.
The fractured interface of the samples will then be visualized under the stereomicroscope (ZEISS Stemi DV4, Germany) for identifying the type of fracture at 32× magnification. Fracture modes of each specimen will be put into one of the three categories:
Two specimens from each of the categories will be randomly selected for SEM analysis by computer-generated randomization. The sticks will then be processed for SEM observation. The specimen surface will be gently decalcified using 36% phosphoric acid for 10 s followed by a rinsing with water for the next 10 s. Deproteinization of the interfacial surface of resin and dentin will be done with 2% sodium hypochlorite solution for 60 s and then washed under running water for 30 s. Serial dehydration of the samples will be undertaken in different concentrations of acetone in ascending order (30, 50, 70, 90, and 100%) for 10 s each. They will then be dried with a Critical Point Dryer (Hitachi HCP-2, Japan). Finally, each sample will be mounted on an aluminum stub with silver paint and sputter-coated with gold by means of the Sputter Coater (Leica EM ACE600 High Vacuum Sputter Coater, Germany). Then, the fracture pattern and de-bonded interface will be assessed under a field emission scanning electron microscope (FE-SEM – ZEISS Sigma 300 VP, Germany) at 5 kV of accelerating voltage.
The primary outcome will be determined by microtensile bond strength whereas the secondary outcome will be determined by fracture modes, i.e., cohesive, adhesive or mixed fracture.
Descriptive statistics will be used for the results of each group using the software (Statistics Version 20; IBM, Armonk, NY). Intergroup comparison will be done on the basis of independent sample t-test to detect the mean difference between the two groups. Independent t-test will be run to analyze the type of failure. In all tests, p values below 0.05 will be considered statistically significant.
Total etch adhesive may show increased microtensile bond strength to carious dentin in molars when treated with 38% silver diamine fluoride as compared to those carious molars which did not receive the intervention of 38% SDF.
The study may provide us with a new restorative technique that will not only be less invasive by preserving the remaining tooth structure but will also prevent the risk of caries progression beneath the restoration. Thus, this will contribute to the longevity of the tooth life by the maintenance of its pulpal health which will contribute to the durability and long-term successful outcome of the direct restoration procedure.
No data are associated with this article.
Although the study concept is good, the methodology requires certain modifications for standardization purpose. Since microtensile bond strength to carious dentine is a study parameter, there is no mention of infected or soft dentine and affected or hard dentine in the manuscript or methodology.
Both the study groups must include removal of soft dentine completely, as the thickness of this layer has a direct impact on microtensile bond strength and otherwise may not give accurate results if the thickness of this layer varies amongst study specimens. The inclusion criteria mentioned deals with only the extent of caries.
Recent documented literature must be included. Some suggestions-
1. Galui S, et al. (2018) [Ref-1]
2. Surendranath P, et al., (2022) [Ref-2]
Is the study design appropriate for the research question?
Partly
Is the rationale for, and objectives of, the study clearly described?
Yes
Are sufficient details of the methods provided to allow replication by others?
Yes
Are the datasets clearly presented in a useable and accessible format?
Not applicable
Reviewer Expertise:
Restorative Dentistry, Endodontics and Cariology
I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
Thank you for your response. I appreciate the raised query regarding the mention of infected and affected dentin.
As per the current protocol, the carious dentin is supposed to be left as it is without engaging in their excavation. The restoration of the tooth will be done keeping the caries intact. As per the inclusion criteria, carious teeth samples with ICDAS scores 4,5 and 6 will be used for the study, which indicates the presence of both infected and affected dentin.