ORIGINAL RESEARCH |
https://doi.org/10.5005/jp-journals-10015-2057 |
In Vitro Assessment of the Wettability of Three Commercially Available Saliva Substitutes on Denture Base Material: A Comparative Study
1Department of Prosthodontics, Vinayaka Mission’s Sankarachariyar Dental College, Vinayaka Mission’s Research Foundation (Deemed to be University), Salem, Tamil Nadu, India
2Department of Pediatric and Preventive Dentistry, JSS Dental College and Hospital, JSS Academy of Higher Education and Research (JSS AHER), Mysore, Karnataka, India
3Department of Oral and Maxillofacial Surgery, Kalinga Institute of Dental Sciences, KIIT (Deemed to be University), Bhubaneswar, Odisha, India
4Department of Oral and Maxillofacial Surgery, S Nijalingappa Institute of Dental Science & Research, Kalaburagi, Karnataka, India
5,6Department of Prosthodontics and Crown, Bridge and Implantology, Srinivas Institute of Dental Sciences, Mukka, Mangaluru, Karnataka, India
Corresponding Author: Aaquib Hashmi, Department of Oral and Maxillofacial Surgery, S Nijalingappa Institute of Dental Science & Research, Kalaburagi, Karnataka, India, Phone: +91 9035351386, e-mail: aaquibhashmi@yahoo.com
ABSTRACT
Aim: To evaluate the wettability of three commercially obtainable saliva substitutes on denture base materials.
Materials and methods: One hundred specimens of heat-cured acrylic resin were fabricated for the purpose of recording the contact angulations of the salivary substitute on its surface. A 100 specimens were randomly allocated into one of the following four groups comprising 25 specimens each: group A: Distilled water, group B: Aqwet, group C: Wet Mouth, group D: Moi-Stir. Using dental plaster the wax specimens were subjected to investment in dental flasks. The traditional method of acrylization was performed as per the recommendations of the manufacturer to procure 100 resin specimens. The specimens were subjected to drying and visualized under the SEM to evaluate the finish. The contact angulations that were advancing/receding were assessed with a goniometer employing the dynamic contact angle evaluation.
Results: The Aqwet group (72.89 ± 1.24 and 64.30 ± 3.02) displayed the lowest mean advancing/receding contact angles, in pursuit by Moi-Stir (79.12 ± 2.04 and 70.67 ± 2.41), Wet Mouth (82.28 ± 2.46 and 76.16 ± 2.70) as well as Distilled water groups (85.31 ± 3.02 and 80.24 ± 2.49). A statistical significant difference with p < 0.001 was noted amid the experimental groups.
Conclusion: Within the limitations of this research, a conclusion arrived at the Aqwet group having lower advancing and receding contact angle values compared to Moi-Stir, Wet Mouth as well as Distilled water groups upon heat-cured acrylic resin. On the basis of the measurements of contact angles, Aqwet salivary substitute exhibited superior wettability of the heat-cures acrylic resins.
Clinical significance: A key characteristic affecting oral ease is the wettability of the denture tissue surface by saliva coupled with complete denture retention, especially in patients affected by xerostomia. Therefore, saliva substitutes consisting of thickening agents provide longer relief, increased moistening, and lubrication of the oral surfaces, hence exhibiting good wetting of the tissue surface of the denture.
How to cite this article: Vellingiri SK, Shivakumar S, Lahiri B, et al. In Vitro Assessment of the Wettability of Three Commercially Available Saliva Substitutes on Denture Base Material: A Comparative Study. World J Dent 2022;13(4):389-393.
Source of support: Nil
Conflict of interest: None
Keywords: Contact angle, Denture base material, Saliva substitute, Wettability
INTRODUCTION
Physical, physiological, psychiatric, mechanical as well as surgical parameters influence the retentive ability of complete dentures. Adhesion, cohesion, atmospheric pressure plus interfacial surface tension constitute the key physical parameters. They function in the layer of fluid amid the denture base and mucosal tissue. Mucins in saliva exhibit rheological characteristics such as adhesion/elasticity that assist in denture retention.1
Saliva is important for normal functioning as well as protective action exhibited on the oral and adjoining gastrointestinal epithelium. The fluid portion of saliva contributes to several functions like cleaning/lubricating the tissues of the mouth, exhibiting solubility, and aiding in making a food bolus, helping in gestation, chewing/speech as well as retaining removable dentures.2
A dry oral cavity resulting from decreased salivation is prone to thinning of epithelium and subsequent irritation. Such a condition makes dental prostheses wear distress. Thus, salivary inadequacy leads to a nonhealthy as well as tender oral mucosa. Loosening of dentures eventually results from xerostomia and ensuing inappropriate retention of dentures, difficulty in mastication, and denture wear.3
Salivary replacements like water may be used though it cannot wet and lubricate the oral hard and soft tissues appropriately. Thus, salivary replacements with thickening substances that aid in enduring relief enhanced wetting, as well as lubrication of the oral tissues, have been formulated. These include formulations like solutions, sprays, and gels with numerous ingredients such as carboxymethylcellulose, electrolytes as well as flavoring agents. An ideal saliva replacement agent must possess properties like a pleasing taste/ smell, being non-toxic and nonaddiction causing, reasonable with appropriate wettability of denture base.4
Wetting of the denture tissue surface is among the key characteristics of denture retention as it offers an atmosphere in which saliva can evenly reach out all surfaces effortlessly. The highly sought factor that concerns the wetting capacity of denture relining substances is the contact angle. The contact angle characterizes the materials in the organization owing to the surface tension of the fluid as well as the surface energy of the solid. An angle that is small signifies superior wettability while a larger angle implies less wettability.5 Thus this research was performed to evaluate the wettability of Aqwet, Wet Mouth, and Moi-Stir saliva substitutes on denture base materials.
MATERIALS AND METHODS
Fabrication and Distribution of Specimens
This in vitro research was performed in the Department of Prosthodontics, Vinayaka Mission’s Sankarachariyar Dental College, India. One hundred specimens of heat-cured acrylic resin were fabricated. DPI (Dental Products of India) was employed in making these specimens for the purpose of recording the contact angulations of the salivary substitute on its surface. A 100 specimens were randomly allocated into one of the following four groups comprising 25 specimens each.
-
Group A: Distilled water
-
Group B: Aqwet (Cipla Ltd.)
-
Group C: Wet Mouth (ICPA Health Products Ltd.)
-
Group D: Moi-Stir (Pharmascience Inc.).
A 100 specimens made of modeling wax of 21 mm (length) by 16 mm (width) by 2 mm (thickness) were designed. Using dental plaster the wax specimens were subjected to investment in dental flasks. The traditional method of acrylization was performed as per the recommendations of the manufacturer to procure 100 resin specimens. Specimens were finished to obtain a uniform thickness of 2 millimeters with the use of burs/stones/sandpaper. The tissue surface in testing was not subjected to finishing in order of replicating the clinical practice setting. The opposite side was subjected to manual finishing with sandpaper to achieve an even flat surface. The specimens were cleansed under flowing water using soap/cotton, followed by cleaning with spirit and ultrasonic decontamination for 15 minutes. The specimens were then subjected to drying followed by examining them under SEM with 2000× magnification to validate their smooth and flat surface finish.
Preparation of the Specimens
Specimens were positioned in a petri dish made of glass after cleansing followed by placement in an oven. The specimens were then subjected to drying at 44°C in the oven for half an hour, followed by cooling to a temperature of 22°C. Air conditioning was employed in controlling the temperature of the room.
Measurements of Advancing and Receding Contact Angle
The contact angulations that were advancing/receding were assessed with a goniometer (DataPhysics, SCA 20) employing the dynamic contact angle evaluation. The liquid medium to be evaluated was placed on the sample using a syringe. The volume of each drop syringed on the flat surfaces was 8 μl. This technique permitted calibration of the quantity of fluid utilized on the surface of the specimen during measurement of the contact angles that were advancing/receding. The procedure also involved the use of a high-speed camera to document modifications of the drop contour that was subjected to dispensing on the specimen surface. The program in the system determined the advancing/receding angles of contact. The contact angle is defined as one between the baseline of the drop and a tangent at the 3-phase line (solid/liquid/vapor). The contact angle formed when a fluid drop forms at the time of dispensing on the dry specimen surface is known as the advancing contact angle. The receding contact angle on the other hand is one that forms following the recession of the fluid from the surface.
Prior to placing a different liquid on the specimen, caution was exercised to rinse the providing syringe meticulously with water, pursued by the liquid to be evaluated. All procedures were performed by two calibrated investigators. Advancing and receding contact angles of all the three fluids onto the 25 specimens in every group were evaluated and documented.
Statistical Analysis
Data analysis was done using the SPSS version 20.0. Calculation of the mean and standard deviation was performed. ANOVA test and Tukey’s post hoc test were used for statistical assessments. ANOVA was performed to evaluate the significance in the dissimilarity of advancing/receding contact angle measurements in the groups tested. Tukey’s post hoc test done for multiple comparison tests was performed to validate the significance of dissimilarity amid advancing/receding contact angle in a pair of groups. A statistical significance was set at a p-value <0.05.
RESULTS
Table 1 and Figures 1 and 2, depict the mean values of advancing/receding contact angles of the various investigational groups. The Aqwet group (72.89 ± 1.24 and 64.30 ± 3.02) displayed the lowest mean advancing/receding contact angles, in pursuit by Moi-Stir (79.12 ± 2.04 and 70.67 ± 2.41), Wet Mouth (82.28 ± 2.46 and 76.16 ± 2.70) as well as Distilled water groups (85.31 ± 3.02 and 80.24 ± 2.49).
| Contact angle | Groups | n | Mean | SD | Min-Max |
|---|---|---|---|---|---|
| Advancing angle | Distilled water | 25 | 85.31 | 3.02 | 68.00–102.20 |
| Aqwet | 25 | 72.89 | 1.24 | 64.30–101.00 | |
| Wet Mouth | 25 | 82.28 | 2.46 | 66.10–102.20 | |
| Moi-Stir | 25 | 79.12 | 2.04 | 64.80–101.40 | |
| Receding angle | Distilled water | 25 | 80.24 | 2.49 | 65.00–101.80 |
| Aqwet | 25 | 64.30 | 3.02 | 58.10–96.00 | |
| Wet Mouth | 25 | 76.16 | 2.70 | 62.20–101.10 | |
| Moi-Stir | 25 | 70.67 | 2.41 | 60.80–98.00 |
Fig. 1: Mean values of advancing contact angles of three experimental different groups
Fig. 2: Mean values of receding contact angles of three experimental different groups
The mean comparative assessment of advancing/receding contact angles of the various investigational groups as delineated in Table 2. The Aqwet group (72.89 ± 1.24 and 64.30 ± 3.02) exhibited the lowest mean values for advancing/receding contact angles in comparison to the remaining groups. A statistical significant difference with p < 0.001 was noted amid the experimental groups.
| Contact angle | Groups | n | Mean ± SD | F-value | p-value |
|---|---|---|---|---|---|
| Advancing angle | Distilled water | 25 | 85.31 ± 3.02 | 12.460 | 0.001 |
| Aqwet | 25 | 72.89 ± 1.24 | |||
| Wet Moutd | 25 | 82.28 ± 2.46 | |||
| Moi-Stir | 25 | 79.12 ± 2.04 | |||
| Receding angle | Distilled water | 25 | 80.24 ± 2.49 | 10.748 | 0.001 |
| Aqwet | 25 | 64.30 ± 3.02 | |||
| Wet Mouth | 25 | 76.16 ± 2.70 | |||
| Moi-Stir | 25 | 70.67 ± 2.41 |
Tukey’s post hoc test showed that the saliva replacements’ multiple comparative assessments of advancing angle amid groups with a significant difference were noted for all experimental groups with the exception of Distilled water as well as Wet Mouth (p > 0.001) as shown by Table 3. Multiple comparative assessments of the receding angles amid groups were noted to be statistically significant among the groups with p < 0.001 and are shown in Table 4.
| Groups | Compared with | Mean difference (I-J) | Sig. |
|---|---|---|---|
| Distilled water | Aqwet | 12.42 | 0.001 |
| Wet Mouth | 3.03 | 0.062 | |
| Moi-Stir | 6.19 | 0.001 | |
| Aqwet | Distilled water | −12.42 | 0.001 |
| Wet Mouth | −9.39 | 0.001 | |
| Moi-Stir | −6.23 | 0.001 | |
| Wet Mouth | Distilled water | −3.03 | 0.062 |
| Aqwet | 9.39 | 0.001 | |
| Moi-Stir | 3.16 | 0.04 | |
| Moi-Stir | Distilled water | −6.19 | 0.001 |
| Aqwet | 6.23 | 0.001 | |
| Wet Mouth | −3.16 | 0.04 |
| Groups | Compared with | Mean difference (I-J) | Sig. |
|---|---|---|---|
| Distilled water | Aqwet | 15.94 | 0.001 |
| Wet Mouth | 4.08 | 0.001 | |
| Moi-Stir | 9.57 | 0.001 | |
| Aqwet | Distilled water | −15.94 | 0.001 |
| Wet Mouth | −11.86 | 0.001 | |
| Moi-stir | −6.37 | 0.001 | |
| Wet Mouth | Distilled water | −4.08 | 0.001 |
| Aqwet | 11.86 | 0.001 | |
| Moi-Stir | 5.49 | 0.001 | |
| Moi-Stir | Distilled water | −9.57 | 0.001 |
| Aqwet | 6.37 | 0.001 | |
| Wet Mouth | −5.49 | 0.001 |
DISCUSSION
The forces needed to fully displace the dental prosthesis from its basal seat are directly associated with the retentive capacity of the denture. An essential prerequisite for denture retention is the wetness of the palatal surface and denture via individual forces of adhesion at both edges. The surface tension of saliva, width of the fluid layer, area of the contact surface, as well as denture-fluid contact angle, influence the forces of retention.6
A key role in complete denture retentive capacity and health of oral tissues is played by saliva. Denture wear can cause extreme discomfort in patients experiencing dryness of the mouth. Palliation of xerostomia can be brought about by artificial salivary substitutes which are highly helpful substances. These salivary replacements can be categorized into two groups: artificial as well as mucin-based replacements. Salivary replacements that have mucin are not in much use as they have porcine ingredients which render them offensive to the populace of India. Thus, this research employed artificial salivary replacements containing synthetic/natural agents that provided the required viscosity plus lubrication.7,8
This research shows that the use of Aqwet delineated superior wetting capability versus the remaining salivary substitutes. There were noteworthy differences, statistically amid mean values of advancing angles with the use of Aqwet versus the other experimental groups. This can be attributed to the lowest angle of contact by Aqwet vs the remaining three groups as the capacity of wetting enhances with decreasing contact angle. This is in accordance with the research of Sharma and Chitre9 and Mathrawala et al.10 who noted that the wetting capacity of Aqwet was superior to the remaining salivary replacement agents studied.
The receding contact angles were significantly lower than the advancing contact angles of the salivary replacements as well as distilled water. The retentive capacity of dentures is directly related to a phenomenon known as “contact-angle hysteresis,” which is the disparity amid the advancing fluid/solid contact angle as well as the receding angle. The contact angle formed when a fluid drop forms at the time of dispensing on a dry surface is known as the advancing contact angle. The receding contact angle on the other hand is one that forms following the recession of the fluid from a solid surface that was formerly wet.11
Measurements of advancing/receding contact angles to evaluate the wetting capacity of denture base agents were investigated by Monsenego et al.12 and Ramanna PK.13 From their in vitro research, they arrived at a conclusion that high-impact heat cure polymethyl methacrylate resins when employed as denture base agents, exhibit the greatest “contact-angle hysteresis” like a higher advancing contact angle plus lesser receding contact angle while showing the most superior wettability.
A study conducted by Bikash P et al.14 found similar comparative results between Aqwet, distilled water, and Wet Mouth. They recommend using Aqwet and Wet Mouth like salivary replacements which have thickening substances for long-lasting respite and enhanced wetting/lubricating ability of various oral areas in individuals with dry mouth. A comparative assessment of the angle of hysteresis was performed for the mean angle of hysteresis for all the investigational groups. The greatest angle of hysteresis was exhibited by Aqwet amid the salivary replacements that imply its higher wetting ability on heat-cured acrylics.
As per research on wettability and contact angles, wetting principally happens when solid and fluid come in touch. Greater wetting ability is exhibited by low contact angles of <90° while lesser wetting ability is noted when the contact angles are >90°. To be specific, contact angles <90° imply that surface wetting would be appropriate and that the liquid would spread over a greater surface area being more hydrophilic. On the contrary, contact angles >90° imply that surface wetting would be inappropriate and that the liquid would refrain from contacting the surface leading to the formation of a drop, being more hydrophobic. Total wetting happens if the angle of contact is 0° as the drop transforms to an even puddle.15,16
The limitations of this research are that the sample size was low and there was a lack of patient reaction for determination of the effectiveness of efficiency of the salivary substitutes which did not lead to correlating of the results to clinical use. Surface contagion of the area investigated may create a variation in the surface tension of water that induces a minor blunder in the measured contact angle values. It is also recommended that the effects of dissimilar surface treatments on the wetting ability of denture materials be assessed in further longer duration trials.
CONCLUSION
Within the limitations of this research, a conclusion arrived at the Aqwet group having lower advancing and receding contact angle values compared to Moi-Stir, Wet Mouth as well as Distilled water groups upon heat-cured acrylic resin. On the basis of the measurements of contact angles, Aqwet salivary substitute exhibited superior wettability of the heat-cures acrylic resins.
REFERENCES
1. Joel Napeñas J, Michael Brennan T, Philip Fox C. Diagnosis and treatment of xerostomia (dry mouth). Odontology 2009;97(2):76–83. DOI: 10.1007/s10266-008-0099-7
2. Mohsin AHB, Reddy V, Kumar P, et al. Evaluation of wetting ability of five new saliva substitutes on heat-polymerized acrylic resin for retention of complete dentures in dry mouth patients: a comparative study. Pan Afr Med J 2017;27:185. DOI: 10.11604/pamj.2017.27.185.9098
3. Mohsin AHB, Reddy SV, Kumar MP, et al. Aloe vera for dry mouth denture patients - palliative therapy. J Clin Diagn Res 2017;11(6):ZC20–ZC23. DOI: 10.7860/JCDR/2017/25084.10036
4. Mendoza AR, Tomlinson MJ. The split denture: a new technique for artificial saliva reservoirs in mandibular dentures. Aust Dent J 2003;48:190–194. DOI: 10.1111/j.1834-7819.2003.tb00031.x
5. Jin NY, Lee HR, Lee H, et al. Wettability of denture relining materials under water storage over time. J Adv Prosthodont 2009;1(1):1–5. DOI: 10.4047/jap.2009.1.1.1
6. Monsenego P, Proust J. Complete denture retention, part I: physical analysis of the mechanism: hysteresis of the solid-liquid contact angle. J Prosthet Dent 1989;62(2):189–196. DOI: 10.1016/0022-3913(89)90312-0
7. Dweck AC. Herbal medicine for the skin – their chemistry and effects on skin and mucous membranes. Pers Care Mag 2002;3:19–21.
8. Aydin AK, Terzioglu H, Ulubayram K, et al. Wetting properties of saliva substitutes on acrylic resin. Int J Prosthodont 1997;10(5):473–477.
9. Sharma N, Chitre V. An in-vitro comparative study of wettability of four commercially available saliva substitutes and distilled water on heat-polymerized acrylic resin. J Indian Prosthodont Soc 2008;8(1):30–35. DOI: 10.4103/0972-4052.43251
10. Mathrawala NR, Hegde RJ. Lacrimo-auriculo-dento-digital syndrome. J Indian Soc Pedod Prev Dent 2011;29(2):168–170. DOI: 10.4103/0970-4388.84693
11. Zissis A, Yanikikkis A, Jagger RG, et al. Wettability of denture materials. Quintessence Int 2001;31(6):457–462.
12. Monsénégo P, Baszkin A, Costa ML, et al. Complete denture retention. Part II: wettability studies on various acrylic resin denture base materials. J Prosthet Dent 1989;62(3):308–312. DOI: 10.1016/0022-3913(89)90338-7
13. Ramanna PK. Wettability of three denture base materials to human saliva, saliva substitute, and distilled water: a comparative in vitro study. J Indian Prosthodont Soc 2018;18(3):248–256. DOI: 10.4103/jips.jips_301_17
14. Bikash P, Seema P. Prosthetic rehabilitation of a xerostomia patient with a mandibular split salivary reservoir denture. Ann essences dent 2010;2(3):32–35 DOI: 10.5368/aedj.2010.2.3.32-35.pdf
15. Yuan Y, Lee TR. Contact angle and wetting properties. Surface science techniques 2013.
16. Eral HB, ’t Mannetje DJCM, Oh JM. Contact angle hysteresis: a review of fundamentals and applications. Colloid Polym Sci 2013;291(2):247–260. DOI: 10.1007/s00396-012-2796-6
________________________
© The Author(s). 2022 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.