|Year : 2015 | Volume
| Issue : 4 | Page : 331-336
Effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness: An in vitro study
Gaurao Vasant Mali, Arun Suresh Dodamani, Gundabaktha Nagappa Karibasappa, Prashanth Vishwakarma Kumar, Vardhaman Mulchand Jain
Department of Public Health Dentistry, ACPM Dental College, Dhule, Maharashtra, India
|Date of Web Publication||18-Sep-2015|
Dr. Gaurao Vasant Mali
ACPM Dental College, Opp. Jawahar Sootgirni, Sakri Road, Dhule - 424 001, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objectives: To assess and compare the effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness over a period of 14 days. Materials and Methods: An in vitro study was done on 40 noncarious deciduous teeth. 10 teeth in each group were dipped in 4 pediatric medicinal syrups (1 sugarfree and 3 conventional) for 1 min thrice daily for 14 days and the enamel surface micro hardness was checked at baseline, 7 th day and 14 th day by Vickers hardness testing machine. The pH, titratable acidity and buffering capacity of the syrups were assessed. Results: The pH of syrups were above critical pH for demineralization of the tooth but tiratable acidity and buffering capacity differed. ANOVA test indicated that the reduction in mean micro hardness was maximum in Group D (Conventional Analgesic syrup) and least in Group A (Sugarfree cough syrup) on 7 th and 14 th day. On intergroup comparison there was no difference (P > 0.05) in micro hardness between Group B (Conventional Cough syrup) and Group C (Conventional Antibiotic). However, highly significant (P < 0.01) difference between the either pair of Group B with Group D, and Group C with Group D on 14 th day. The percentage reduction in micro hardness on 14 th day was maximum for Group D (24.4 ± 2.2) and minimum for Group A (14.0 ± 1.3) which was statistically significant (P < 0.01). Conclusion: Sugar free pediatric medicines can be effective in reducing dental erosion and efforts should be made to incorporate sugar substitutes in formulation of pediatric medicines.
Keywords: Micro hardness, pediatric syrup, primary teeth, sorbitol
|How to cite this article:|
Mali GV, Dodamani AS, Karibasappa GN, Kumar PV, Jain VM. Effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness: An in vitro study. J Indian Soc Pedod Prev Dent 2015;33:331-6
|How to cite this URL:|
Mali GV, Dodamani AS, Karibasappa GN, Kumar PV, Jain VM. Effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness: An in vitro study. J Indian Soc Pedod Prev Dent [serial online] 2015 [cited 2019 Dec 6];33:331-6. Available from: http://www.jisppd.com/text.asp?2015/33/4/331/165707
| Introduction|| |
Children are future of our society and ensuring their overall good health is of utmost importance. Mouth is the mirror of our body, and oral health is essential for children's growth, development, and general health. Dental caries is the common oral disease and the most prevalent infectious disease in the oral cavity. Among the theories that explain caries onset, universally accepted is the action of acids produced by bacterial fermentation of carbohydrates (sugars) from the diet. However, some diseases or medications may increase the risk or severity of caries, and dental erosion is one of them. 
Dental erosion is defined as a progressive loss of dental hard tissues by chemical dissolution without bacterial involvement.  In modern society, the changing lifestyle has contributed to an increased incidence of dental erosion, especially in children and adolescents. , Erosive tooth wear is a multi-factorial irreversible process that may be caused by intrinsic, extrinsic, or idiopathic factors.  The intrinsic etiologic factors are related to the contact of tooth tissues with stomach acids (i.e., regurgitation and reflux disorders).  Increased acidic food and drink consumption has become the primary extrinsic source of dental erosive agents, although acidic medicines, and behavioral factors have also been identified as extrinsic etiologic factors in dental erosion. ,,,
Liquid oral medications are usually prescribed for children in order to avoid the difficulty encountered in taking medicines in other forms.  Furthermore, these medicines are acidic preparations as they are often necessary for drug dispersion, chemical stability maintenance, to ensure physiological compatibility, and to improve flavor. In addition to the acidic components, other factors such as prolonged and frequent ingestion (i.e., two or more times daily), bedtime and between meals consumption, high viscosity, and the collateral effect of reduced salivary flow, may contribute to increase the risk for medication-induced dental erosion. ,,
Few in vitro researches reported that medications can affect enamel hardness, and cause morphological alterations. Nevertheless, the results of these studies are limited to a small number of medicines, and the literature is scarce that investigate the effect of medications on permanent and deciduous tooth enamel. 
Several liquid medications can be part of the daily routine of children with chronic diseases.  Antibiotics and cough syrups are the most common sugar-containing medications regularly used for young children. 
Off late, various sugar substitutes have been introduced and are widely used in food products to avoid tooth decay from sugar and other fermentable carbohydrates. Many studies have shown sugar substitutes to be noncariogenic.  The use of sugar substitutes in preparation of pediatric medicines is still at very minimal level. However, there is an increased use of oral medicines by children for prolonged periods, especially those with chronic diseases, thus, the aim of the present study was to assess in vitro, with stating null hypothesis that there is no effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness. 
| Materials and Methods|| |
Ethical clearance for the study was obtained from Institutional Ethical Review Board of A.C.P.M. Dental College Dhule, Maharashtra. The present study was an in vitro study to assess and compare the effect of conventional and sugar-free pediatric drug formulations in syrup form on primary tooth enamel hardness. List of all the commonly prescribed pediatric syrup medications were collected from Indian Medical Association Branch Dhule, Maharashtra. 3 conventional and 1 sugar-free syrups were randomly selected and tested for initial pH, titratable acidity, and buffering capacity.
Preparation of specimens
Noncarious deciduous teeth (40 incisors and molars) were collected from the Department of Pedodontics, A.C.P.M Dental College Dhule. Prior to the study, the teeth were cleaned using pumice-water slurry and 0.3-µm alumina paste with a polishing brush at low-speed handpiece (5000 rpm) to remove any debris or calculus deposited on to the teeth.  Then, they were preserved in artificial saliva and transported to microhardness testing laboratory.
Each crown was fixed with plastic wax in the central orifice of an acrylic plate. The tooth was placed and stabilized with red wax with a buccal surface facing upwards using a parallelometer (ElQuip, São Carlos, SP, Brazil) to secure the flattest region of the buccal surface parallel to the plate. The specimens had their buccal enamel surfaces flattened with 600 and 1200-grit Al2O3 abrasive papers (Buehler Ltd.), polished with 0.3-μm alumina paste (Alpha and Gamma Micropolish; Buehler Ltd.,) and felt paper using a water-cooled low-speed polishing machine (Politriz DP-9U2; Struers A/S, Copenhagen, Denmark). The specimens were ultrasonically cleaned in deionized water for 10 min. The test sites were demarcated by attaching a piece of insulating tape with a 2-mm diameter central hole on each surface. The tooth/plate sets were rendered acid-proof by coating them with 2 layers of cosmetic nail polish. The previously delimited circular area on the flattest region of the buccal surface was left uncoated. Then, the specimens were stored at 37°C in a 100% relative humidity environment in artificial saliva. 
Assessment of the initial enamel surface microhardness was done using Vickers hardness testing machine (Digital display microhardness tester HVS-1000A) at microhardness testing laboratory at Metallurgical Services Ghatkopar, Mumbai. The force of 25 g was applied with the diamond indenter on to the enamel surface at three points 100 µm apart, and the average of the readings was obtained as Vickers hardness number. 
After the assessment of baseline microhardness, the teeth specimens were demounted and randomly 10 teeth in each group were allocated into four groups - Group A (sugarfree cough syrup - M solvin, contents - guaiphenesin, ambroxol hydrochloride, terbutaline, sorbitol, Ipca laboratories Ltd.), Group B (conventional cough syrup - trustyl M, contents - guaiphenesin, ambroxol hydrochloride, terbutaline, abbot laboratories Ltd.), Group C (conventional antibiotic - althrocin liquid, contents-erythromycin estolate, alembic pharmaceuticals Ltd.), Group D (conventional analgesic - zukamin cold syrup, contents - paracetamol, chlorpheniramine, alkem laboratories Ltd.,). 10 teeth in each group were immersed into the 10 ml undiluted syrup in test tube and agitated for 1 min thrice daily for 7 days.  The teeth were preserved in artificial saliva and transported to microhardness testing laboratory, there teeth were remounted, and their surface enamel microhardness was measured.
After measurement of microhardness, the teeth were demounted and further immersed into the 10 ml syrup for 1 min thrice daily for next 7 days and again transported and mounted for microhardness measurement. Intermittently, after immersion of the teeth for 1 min in the syrups they were washed with distilled water and preserved in artificial saliva with daily change of the solution.
Preparation of artificial saliva
Artificial saliva was prepared at the Department of Chemistry, S.S.V.P.S Arts, Commerce and Science College Dhule, Maharashtra.
Composition of artificial saliva
Methylhydroxybenzoate 2.0 g, carboxymethylcellulose 10.0 g, KCl 0.625 g, MgCl2.6H 2 O 0.059 g, CaCl2.2H2O 0.166 g, K2HPO4 0.804 g, and KH2PO4 0.326 g in 1000 ml of deionized water. 
pH measure and buffering capacity
The pH value of the syrups used for the immersion of the teeth and the amount of base required to raise the pH to 7.0 (titratable acidity) were measured with a pH meter (Reena Instruments Co. Pvt. Ltd., Delhi, Water and Soil Analysis kit). To measure titratable acidity, 20 g of each drink or solution was titrated with 0.5 M NaOH in 0.02 ml increments at 25°C. The buffering capacity (β) was calculated with the following equation: β = −ΔC/ΔpH in which ΔC is the amount of base used and ΔpH is the change in pH caused by the addition of the base.
All statistical procedures were performed using Statistical Package for Social Sciences (SPSS) 20.0 software (IBM, Armonk, NY, United States of America). The data exhibited a normal and homogeneous distribution; thus, microhardness was analyzed using mean VHN score employing ANOVA and Tukey's least significant difference multiple-comparison test with time and medication as study parameters.
| Results|| |
Before the start of the study the pH, titratable acidities and buffering capacities of the syrups were calculated and the readings were tabulated [Table 1].
Microhardness of the tooth specimens were assessed at baseline, 7 th and 14 th day. The mean hardness was least in Group D and maximum in Group A on 7 th and 14 th day [Table 2].
|Table 2: Surface hardness of tooth in four groups at baseline, 7 th and 14 th day|
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On 7 th day mean surface hardness of B, C, and D was lower than A difference was statistically significant (P < 0.05). There was no significant (P > 0.05) difference in mean hardness between B, C, and D group [Table 3]. However, on 14 th day surface hardness of group B, C, and D was lower than A (P < 0.01). There was no difference (P > 0.05) in between B and C group and highly significant difference (P < 0.01) between B and D, and between C and D group on 14 th day [Table 3]. There was a reduction in microhardness of the teeth on 7 th day and 14 th day, but on comparing percentage reduction in microhardness between 7 th and 14 th day maximum percentage reduction was in Group D (24.4 ± 2.2) and minimum for Group A (14.0 ± 1.3) and was statistically significant (P < 0.01) [Table 4].
|Table 3: Intergroup comparison of surface hardness of tooth in between four groups at baseline, 7 th and 14 th day|
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|Table 4: Percentage reduction of surface hardness of tooth in four groups at 7 th and 14 th day|
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| Discussion|| |
The present research provides evidence that the studied medicines could potentially erode deciduous tooth enamel after successive immersion cycles. The surface enamel microhardness of the teeth was decreased after 14 days in all the four groups of medicinal syrups, however, the teeth immersed in Group A (Sugar free cough syrup) showed the least reduction in microhardness as compared to other three groups.
Acids are added to drug formulations as buffering agents to maintain chemical stability, control tonicity, physiological compatibility, to enhance flavor, and thereby increasing the palatability to children.  Citric acid is the most commonly used primary acid in the oral medicines, despite being a weak acid, citric acid is a potent erosive agent. , These acids were present in the medicinal syrups used in this study and pH of all the syrups were above the critical pH of demineralization. Few authors have reported, as the pH decreases, the potential of enamel erosion increases. ,,
Nevertheless, the erosive potential of a substance is not exclusively dependent on pH value. The erosion potential is also strongly influenced by titratable acidity, buffering capacity, calcium chelation properties, mineral content, and adhesion to the dental surface. Hence, titratable acidities and buffering capacities were the physicochemical properties analyzed in this study. Titratable acidity represents the total content of acids and is considered as an indication of the strength of the erosive potential of the syrup and buffering capacity is the time taken by saliva to neutralize the acid in the syrup. ,, A previous study that was done revealed high titratable acidity in liquid medications confirming their erosive nature. 
In current study, the titratable acidities and buffering capacities of the syrups differed. Group C (conventional antibiotic) exhibited the largest titratable acidity (175 mmol/L), and Group D (conventional analgesic) exhibited the maximum buffering capacity (144.5 mmol/L) [Table 1]. The most probable reason attributed for this difference could be due to the compositions of the syrups, the alcohols added, the viscosity, the surface tension of syrups, the acids present in their formulations (citric, phosphoric, hydrochloric, tartaric, benzoic, etc.), and the buffering agents (citrate buffers) added in their preparations. The properties of the different constituents present in the syrup may have also caused a difference in the buffering capacities. 
There was microhardness reduction seen in all the four groups on the 7 th day and 14 th day as compared to baseline values, and sugar-free syrup showed the least reduction in microhardness and was statistically significant. Conventional syrup group comparison on 7 th day showed no statistical significant difference [Table 2] and [Table 3]. The reason for more reduction in microhardness on the 14 th day as compared to 7 th day could be due to longer duration of exposure to medicinal syrups [Table 3].
In the present study, there was a linear percentage reduction in microhardness of all groups from baseline to the 14 th day. Moreover the reduction was more pronounced in a conventional group than sugar-free group after 7 th day onward. This difference observed in different groups might be due to their different titratable acidity, buffering capacity, pH, the acids used, the buffers added, and the compositions of the medicinal syrups [Table 4].  Similar findings were seen by Scatena et al. 
Studies on deciduous tooth substrates are of scientific relevance because structural and morphological differences between deciduous and permanent substrates have been observed. Furthermore, differences in the chemical composition, rate of formation and ultrastructural appearance between the pellicle on primary and permanent teeth have been reported.  In vitro studies have observed the erosive potential of medicines and have reported alterations in enamel surface microhardness and tooth morphology. However, most of the studies were performed on a permanent tooth substrate.  There were very few studies that evaluated the enamel erosive effects of the medications on deciduous teeth. Hence, deciduous teeth were selected in this study to check for their microhardness.
Saliva has a role in forming the salivary protein-based pellicle on enamel tooth surfaces, which behaves as a diffusion barrier to prevent direct contact between acids and the tooth surface, thus preventing the demineralization process. , Hence an artificial saliva medium was used between the immersion cycles for preservation of the teeth because of its proven ability to exert similar remineralizing effect as that of fresh human saliva and care was taken to replace it daily. 
The erosive potential of an acidic challenge might also be related to the frequency and time of acid exposure as well as by the total volume of acid media ingested. In addition to the properties of the medications, the indiscriminate use of liquid formulations (syrups) by young children can increase the risk for dental erosion because the administration of liquid oral medications at bedtime which is not followed by proper oral hygiene after ingestion of the substance.  Therefore, the experimental period of 14 days was chosen for this study to assess the effect of medications for longer duration. The syrups used in this study were selected because they were most commonly prescribed and easily available.
In the current investigation, the protocol used was based on the following frequency of syrup ingestion: 10 ml taken 3 times a day, under agitation of the solution during the specimen immersion period and this agitation was done because according to some authors, when a substance is ingested, a certain agitation occurs, which favors the substance capacity to cause erosion. 
Nowadays various sugar substitutes have been widely used in food products and beverages to avoid tooth decay from sugar and other fermentable carbohydrates. However, other ingredients, such as citric or phosphoric acids in beverages, may cause dental erosion. Most commonly used sugar alcohols are xylitol, sorbitol, etc. Studies on xylitol, carried out in Russia, Hungary, and Estonia, have shown that xylitol is noncariogenic.  Along with xylitol, sorbitol has also been proved to be effective sugar substitute in reduction of dental caries but very few cough syrups are available for pediatric use which contain sorbitol in their composition and very few studies have been carried out on the same.  Hence in this study a sugar-free cough syrup containing sorbitol was used to check for its effect on the microhardness of teeth.
Thus, the present study emphasized to assess and compare the effect of conventional and sugar free pediatric medications on primary tooth enamel hardness and the importance of sorbitol-containing pediatric medications to minimize dental erosion. The parameters, titratable acidities, buffering capacities used in this study have an impact on the microhardness, but these parameters are not enough to validate the results of the study. Along with these parameters, the compositions of the syrups and the total dissolved sugars should also be assessed to see the exact impact on the microhardness.
Sorbitol-containing medications have proved to be helpful in reduction of microhardness, but they have to be cautiously used in pediatric patients in proper doses because of their proven side-effects. Further clinical trials are required to assess its safety and adverse effects on tooth enamel.
| Conclusion|| |
Sugar substitutes have been proved to be noncariogenic and tooth - friendly component. Though their use is minimal, efforts should be made to incorporate them in formulation of pediatric medicines by the pharmaceutical companies and health care professionals should start prescribing these sugar-free pediatric drug formulations keeping in mind their benefits and side-effects for pediatric use.
The authors would like to thank Dr. N.N. Pawar, Ph.D, H.O.D, Dept. of Organic Chemistry, S.S.V.P.S Arts, Commerce and Science College Dhule, Maharashtra for helping out with preparation of artificial saliva and measurement of pH, titratable acidities and buffering capacities of the medicinal syrups and Dr. Prashant Patil, Biostatistician, Hire Medical College, Dhule for helping them with statistical analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]