|Year : 2016 | Volume
| Issue : 2 | Page : 60-63
Comparative evaluation of effect of different beverages on surface hardness of nanohybrid resin composite: An in vitro study
Chandani M Bhatia1, Manoj Chandak1, Adwani Rahul2, Shweta Sedani1, Rakhi Chandak3, Nitin Adwani4, Abhilasha Dass1, Poonam Bhatiya (Harjani)5
1 Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College and Hospital, Nagpur, India
2 Department of Prosthodontics, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Nagpur, India
3 Department of Oral Diagnosis and Medicine, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Nagpur, India
4 Department of Oral and Maxillofacial Surgery, VYWS Dental College and Hospital, Amravati, India
5 Department of Pedodontics and Preventive Dentistry, Sharad Pawar Dental College and Hospital, Nagpur, Maharashtra, India
|Date of Web Publication||5-Jan-2017|
Chandani M Bhatia
Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College and Hospital, Nagpur
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aims: Aim of the present study is to compare and evaluate the effect of different beverages on surface hardness of nanohybrid resin composite in an invitro model. Materials and Methods: Eighty specimens of nanohybrid resin composite were prepared and divided into four group, i.e., twenty each. They were then immersed in beverages and then subjected for microhardness testing. The machine used for testing is Vicker's microhardness. Results: Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05) and much difference was found within first 7 days. Conclusion: The effect of beverages on the surface of restorative material depends on the exposure time and chemical composition of beverages.
Clinical Relevance To Interdisciplinary Dentistry
Consumption of acidic food, fruit juices, soft drinks, coffee, tea, or wine can result in surface damage and decrease hardness and esthetic qualities of a restorative material.
Keywords: Beverage, microhardness, resin composite
|How to cite this article:|
Bhatia CM, Chandak M, Rahul A, Sedani S, Chandak R, Adwani N, Dass A, Bhatiya (Harjani) P. Comparative evaluation of effect of different beverages on surface hardness of nanohybrid resin composite: An in vitro study. J Interdiscip Dentistry 2016;6:60-3
|How to cite this URL:|
Bhatia CM, Chandak M, Rahul A, Sedani S, Chandak R, Adwani N, Dass A, Bhatiya (Harjani) P. Comparative evaluation of effect of different beverages on surface hardness of nanohybrid resin composite: An in vitro study. J Interdiscip Dentistry [serial online] 2016 [cited 2019 Dec 5];6:60-3. Available from: http://www.jidonline.com/text.asp?2016/6/2/60/197663
| Introduction|| |
Increased demand by patients and clinicians for esthetic restorations coupled with the public's concern which has resulted in an escalating use of resin composite materials worldwide in dentistry.  Nanohybrid, the newer resin composite restorative material, is becoming popular as it combines physical, mechanical, and excellent esthetic properties. The average particle size of nanohybrid is less than that of microfilled composites resins. It has tooth-like translucency and is highly polishable, has good color stability, stain resistance, high wear strength, and can be used for anterior and posterior restorations.
Nowadays, people are concerned about health and are interested in healthy drinks and fruit juices. Consumption of acidic food, fruit juices, soft drinks, coffee, tea, or wine can result in surface damage and decrease hardness and esthetic qualities of a restorative material. 
There are a number of studies reporting the different surface hardness effects of beverages on resin composite, but only a few of the studies reported effects of orange juice, aerated drinks, tea, and beer on surface hardness of nanohybrid resin composite. Five second time was selected for immersion because during beverages consumption, drink contacts only for short period of time with the tooth surfaces before it is washed away by saliva. Therefore, this study was thus designed to simulate the washing effect of saliva of an individual drinking by cyclic specimen immersion. 
Therefore, the objectives of this study were to compare the effects of different beverages (orange juice, aerated drinks, tea, and beer) on surface hardness of nanohybrid resin composite.
| Materials And Methods|| |
The customized rectangular Teflon mold was prepared. The Teflon mold consist of five customized indentations, and the dimensions of indentations, i.e., height and diameter of mold was 5 mm × 5 mm, respectively.
Eighty specimens of nanohybrid resin composite were prepared in a Teflon mold for surface microhardness profile measurement. A glass slide and Mylar strip were then placed over the filled mold to provide a smooth and flat surface, after which light pressure (20 N) was applied and were polymerized for 40 s. Mechanical preparation of specimens was not performed.
The pH and titratable acidity measurements
Four beverages used in this study were orange juice, aerated drink, tea, and beer. A pH meter (Elico LI 127 pH meter) was used to determine pH of all beverages. Ten pH readings of freshly prepared drinks were obtained to give a mean pH measurement for each beverage. To determine titratable acidity or buffering capacity, 20 mL of each beverage was added by 0.5 mL increments of 1 mol/L sodium hydroxide (NaOH). The amount of NaOH required to reach pH levels of 5.5, 7, and 10 was recorded. The titrations for each beverage were also repeated 10 times to obtain a mean value. Mean pH of beverages found was tea: 7, aerated drink: 3, orange juice: 4, and beer: 5. To maintain the original pH level of the beverages, they were refreshed daily throughout the experiment. The specimens' immersion protocol simulated an individual eating acidic food, sour fruits, and drinks. The pH values present only a measure of the free hydrogen ion concentration. It does not present the hydrogen ion remaining in the undissociated form. Thus, the potential degradation of acidic agents should be considered for both the pH value and titratable acidity.
Eighty specimens were divided into four groups of twenty specimens. The specimens were alternately immersed in 25 mL of a beverage for 5 s and in 25 mL of artificial saliva for 5 s for ten cycles. The same protocol was done for 28 days consecutively. The beverages were refreshed daily to maintain the pH level. The specimen immersion protocol simulated an individual eating acidic food, sour fruits, and drinks. After the immersion sequence was completed, the specimens were rinsed with deionized water, blotted dry, and subjected to surface microhardness testing.
To obtain a baseline value, each group was subjected to surface microhardness measurement. The hardness value (kg/mm 2 ) of each specimen was determined using a microhardness tester (DVH 3000 operation manual, chroma system) with a diamond Vickers indenter. The surface hardness test was carried out at the following intervals, before immersion, and then subsequently at 7, 14, 21, and 28 days. Gradual changes in surface microhardness were recorded at each time interval.
One-way ANOVA and multiple comparison post hoc Bonferroni-Holm test. Mean microhardness and standard deviations of materials tested immersed in different beverages at different times (kg/mm).
| Results|| |
[Figure 1] shows the maximum decrease in microhardness was found with aerated drink followed by orange juice, tea, and beer.
|Figure 1: The maximum decrease in microhardness was found with aerated drink followed by orange juice, tea, and beeruntil the end of the 28 days period, and the greatest change in hardness occurred within the first 7 days |
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[Figure 2] shows microhardness values of all groups decreased from the initial week of immersion until the end of the 28 days period, and the greatest change in hardness occurred within the first 7 days.
|Figure 2: Microhardness values of all groups decreased from the initial week of immersion until the end of the 28 days period, and the greatest change in hardness occurred within the first 7 days|
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| Discussion|| |
All groups showed decreased microhardness values from the initial week of immersion until the end of the 28 days period, and the greatest change in hardness shown occurred within the first 7 days. The specimens were not exposed to any mechanical forces so any observed change in hardness would be a chemical reaction or dissolution.  In the oral cavity, restorative materials are exposed to varying environments. Such variables are changes in temperature and acidic-base conditions from food and drinks. Therefore, the restorative materials used in the mouth should resist or show minimal change in these situations.  Not only the pH of acid drink is responsible for erosive potential but erosion is also strongly influenced by its titration. It is generally accepted that titrable acidity is the better indicator of erosive potential. The reason being the pH values measure the free hydrogen ion concentration and does not present the hydrogen ion present in undissociated form. ,
Aerated drink has the lowest titratable acidity, and it is a carbonated beverage containing carbonic acid and phosphoric acid which promotes dissolution and it easily erodes the materials. 
Degradation of the resin-filler interface and inorganic fillers also decrease the surface hardness.  This explains why nanohybrid resin composite shows decrease hardness when exposed to beverages. The types of resin are influenced by water absorption of polymer-based materials. Hydroxyethylmethacrylate (hydrophobic resin) absorbs more water than one like bis-GMA. The water absorption of materials is affected by filler loading and with higher filler loading material expecting to show a lower uptake. The presence of voids during the mixing or producing these materials is the factor which influences water absorption of polymer-based tooth-colored filling materials. 
Orange juice is composed of citric acid. Phosphoric acid softens materials more than citric acid and carbonic acid thus indicating that aerated drinks cause more reduction in microhardness as compared to natural fruit juices. However, citric acid has been shown to be aggressive for dental hard tissues and resin-based restorative materials.  The present study showed a decrease in the microhardness more with aerated drinks than orange juice.
In the present study, microhardness decreased from the 1 st week until the end of the 28 days period of immersion in tea. Since the pH of tea is nearly 7, the water in the tea can degrade polymer materials. , The polymer materials absorb water, and there is a loss of chemical bond between filler particles and the resin matrix. Decrease in hardness occurs due to dislodgment of filler particles from the outer surface of the material.
Alcohol in beverages softens polymer matrices and dislodges filler particles. This results in a rapid decrement in microhardness.  The result of the present study also showed the decrease in microhardness from the 1 st week until the end of 28 th day period of immersion in beer. These findings correlate with those of McKinney and Wu, and also Tanthanuch et al. in their studies.
It should be noted that there were some limitations to this study, like it does not examine the in vivo effects of beverages, further studies are required to examine the effects of beverages in vivo.
| Conclusion|| |
Within the limitation of this study, the following conclusions were drawn, all the beverages used significantly reduced the microhardness, immersion in aerated drink caused more surface hardness reduction over time than other beverages. The effect of these beverages depends on the exposure time and chemical composition of the restorative material and beverages.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]