Evaluation of effects of commonly used carbonated beverages and commercially available tooth pastes on enamel: An in vitro study

Tooth wear or the loss of the tooth surface is considered to be the next most significant threat to the human dentition, after trauma, dental caries and periodontal diseases. High risk of enamel erosion is noted in various parts of India due to consumption of carbonated beverages amongst various age groups. Loss of enamel due to usage of dental abrasives present in the commercially has been a major of concern over the past decade. Although REA and RDA levels are tested before the public usage, some amount of enamel loss occurs over the long run. This study investigates the possible loss of enamel due to consumption of popular carbonated beverages and commercially available toothpastes and their synergistic effects. Introduction Tooth wear is the term used to describe the progressive loss of a tooth’ s surface due to actions other than those which cause tooth decay or dental trauma. It is considered to be the next most significant threat to the function and longevity of human dentition, after trauma, dental caries and periodontal diseases. Tooth wear may occur due toerosion, abrasion, attrition or abfraction. Dental erosion is defined as tooth wear due to dissolution of dental hard tissues by acids without the involvement of bacteria. 1 With over half of 15-18 year olds exhibiting incisal erosion, it is being seen more commonly and frequently in adults and children. 2 Recent studies show that there is a high risk of enamel erosion due to carbonated beverages among the teenagers in parts of India. 3 Several factors such as, chemical properties of the erosive medium and the frequency and the method of contact between acid and tooth lead to erosion. Also, factors such as effectiveness of the protective mechanisms in the oral cavity, which includes salivary composition, flow rate, buffering capacity, pellicle formation, clearance rates and individual dental anatomy results in erosion of teeth. 4 Consumption of carbonated beverages leading to dental erosion is a growing problem. Irreversible loss of enamel from tooth surface is resulted with exposure to an erosive medium and a layer of softened enamel 0.5-5 μm thick may be worn out. 5,6 EFFECTS OF COMMONLY USED CARBONATED BEVERAGES AND TOOTH PASTES ON ENAMEL 3(3);2017 31 Journal Of Applied Dental and Medical Sciences 3(3);2017 Dental abrasion is the wearing away of the hard tissues of oral cavity through physical means other than teeth. Tooth pastes, which typically contain abrasives and detergents, are used as cleansing and discolouration removal agent. 7,8 It is widely accepted that tooth pastes require some amount of abrasivity to remove or reduce stains. Since, softened surface is more susceptible to abrasion, brushing the teeth immediately after consumption of carbonated beverages accelerates enamel loss. 9,10 The softened tooth enamel is worn out if the time for remineralisation of enamel is insufficient and abrasion occurs immediately after erosion. 9,10 Attrition is loss of tooth substance caused by physical tooth-to-tooth contact, such as may occur in bruxism. A degree of attrition is normal, especially in elderly individuals. 17 While, abfraction is loss of cervical tooth substance purportedly caused by flexure of teeth under occlusal loading. 18 Tooth wear is common from early age, suggests epidemiological data. 11,12 Though erosion may be a dominant factor in a majority of surveys considering tooth wear, multi-factorial etiology of the condition would suggest that wear scores are a result of interaction between various physical and chemical agents. 13 Thus, hard tissue loss from the surface of the teeth are a synergistic effect of surface attrition, abfraction, erosion and abrasion. 14 Soft drink or non-alcoholic beverages are one of the major reasons causing erosion. 13 While, for abrasion, the focus is on toothpastes, since certain degree of abrasivity is needed for efficient cleaning and stain removal. 15 It has been noted enamel, though is resistant to significant abrasion by most toothpastes, and is highly sensitive to erosion by acid substances. Radiotracer methods are used to put limit on degree of abrasivity by international and national standards on the toothpastes. Relative Dentine Abrasivity (RDA) and Relative Enamel Abrasivity (REA) levels are tested before releasing a toothpaste for public usage. 16 However, it is interesting to know the synergistic effect of abrasion by toothpastes after erosion by beverages on the total amount of tooth wear. This study aims to evaluate the erosive effects of some of the commonly used carbonated beverages, the abrasive effects commercially available toothpastes and their additive effect. It will be interesting to see the amount of tooth wear caused by the beverages and toothpastes present in the present day Indian markets. Profilometer is ideal to measure the surface roughness of the tooth. Unlike hardness testers, these systems do not damage the surface of the tooth while measuring and also account for good precision and accuracy. The abrasion effects of various toothpastes must be evaluated under similar conditions to produce effective and accurate comparison. Hence, a machine with a definite load and frequency is necessary to abrade the all the selected samples. Such a study is the need of the hour keeping in mind the increasing consumption of beverages and the number of toothpaste brands available in the society. A better knowledge of their effects will help in preventing the adverse effects of tooth wear like dental sensitivity, caries, gross destruction of tooth and also, poor aesthetics. MATERIAL AND METHODOLOGY Beverages and toothpaste: Four commercially available beverages (B1, B2, B3 and B4) were selected based on their sales and popularity and their pH was determined using a pH meter, samples with least pH were selected for the EFFECTS OF COMMONLY USED CARBONATED BEVERAGES AND TOOTH PASTES ON ENAMEL 3(3);2017 32 Journal Of Applied Dental and Medical Sciences 3(3);2017 study. Four toothpastes (T1, T2, T3 and T4) were chosen of which two were multinational brands while the other two were Indian herbal toothpastes. Figure 1: Extracted teeth embedded in acrylic blocks Figure 2: Acrylic block This study was a single blind study and the operator was not aware of the identity of the brands. Sample Preparation: One hundred and fifty previously extracted teeth samples were first collected and then cut from the sides with the help of water cooled diamond saw. These samples were then placed in polyurethane moulds and embedded into epoxy resin for a day. Samples were then ground and polished using a polishing unit. A baseline measurement of each sample would be taken using Profilometer. The samples were randomly allocated to four sub groups of fifteen samples each for each of group A and B. A separate group with fifteen samples would be used as control. Profilometric analysis: A profilometer is a device used to measure the surface roughness of the given sample. The profilometer gives a tracing of the sample using digital and analog Figure 3: pH strips indicating the pH of sample beverages Figure 4: Profilometer Figure 5: Customized Brushing Machine hardware and software. It calculates the average surface roughness (RA) value for the resultant EFFECTS OF COMMONLY USED CARBONATED BEVERAGES AND TOOTH PASTES ON ENAMEL 3(3);2017 33 Journal Of Applied Dental and Medical Sciences 3(3);2017 tracing. 25 The surface roughness was measured using the profilometer (Taylor Hobson Precision SURTRONIC 3+) for each specimen and values were recorded before and after the experimentation. Group A: Erosion Subgroups ( B1, B2, B3, B4 and B5) Fifteen teeth samples in each subgroup were simultaneously exposed to 500ml of selected beverage with continuous stirring for uniform contact of all surfaces. The samples were then removed after 20 minutes and rinsed with distilled water. These specimens were exposed to air for drying. This process was repeated with beverage B1, B2, B3 and B4 for 15 days. A separate group of fifteen samples was used as control in sub group B5 and was immersed in synthetic saliva (Potassium: 20 meq/lit, Chloride: 27.4 meq/lit, Sodium: 0.22 mg, Magnesium: 1.5 mg, Calcium: 0.6 mg, Fluoride: 0.5 mg, Phosphorous: 0.21 mg, Hydroxy propyl methyl cellulose 3%). Group B: Abrasion Subgroups (T1, T2, T3, T4 and