The Effect of Prevident and Pronamel in the Prevention of Chemical Erosion: A Comparative Study

Headnote

Abstract

Aim: This study aimed to evaluate the efficacy of Prevident and Pronamel in preventing chemical erosion

Materials and methods: Samples were prepared from unerupted third molars which were then checked by a surface profilo-meter for surface roughness. Samples with a surface roughness of 0.3 urn were included in the study which were then treated by prevident and pronamel followed by exposure to an erosive challenge by orange juice. Post-treatment the surface roughness was measured again and the results statistically analysed.

Results: Statistically significant mean values were obtained for different groups pre-treated by Group I (Prevident), Group II (Pronamel) and Group III (control).

Conclusion: The results showed that Prevident prevented chemical erosion more than Pronamel and thus is a better reminera- lising paste.

Keywords: Prevident, Pronamel, orange juice, profilometry, erosion.

Introduction

Dental erosion is a relatively new risk factor for dental health, introduced by today's lifestyle. This dental lesion is defined as loss of tooth substance by chemical processes not involving bacteria.1 There are 4 main factors that cause tooth erosion: quality of the tooth structure, buffer capacity of the oral environment, intrinsic factors of the patients and extrinsic factors. Gastrointestinal disease is an example of the intrinsic factors that result in regurgitation of acid into the mouth, and acidic food and drinks are examples of extrinsic factors.2 Softdrinks and juices are an important factor in tooth erosion, because they contain acids such as citric acid, maleic acid and phosphoric acid, which decrease the pH of the oral environment. In addition, softdrinks also contain sugar that plaque micro-organisms require for the fermentation process and later produce acid that causes dissolution of the tooth enamel. The degree of tooth erosion can be decreased by removing its cause or reducing factors that enhance it.3

It is not always possible to eliminate the causes of tooth wear in individuals, so it is desirable to develop other effective preventive strategies to manage tooth wear which include enhancement of acid resistance to tooth structure and the remineralization process, which requires calcium. phosphate and fluoride, all of which are components of saliva.4 The 2 recently introduced fluoridated pastes are Prevident (Colgate-Palmolive, NewYork) and Sensodyne Pronamel GlaxoSmithKline, Middlesex, UK). Both these pastes contain high level bioavailable fluoride for use as a dental caries preventive agent in adults and paedia- trie patients.

The aim of this in-vitro study was to examine whether a single topical application of these 2 products, Prevident and Pronamel would reduce enamel erosion caused by orange juice.

Materials and Methods

Preparation of samples: 35 unerupted third molars were collected from donors who were resident in areas where the water supplies contained low concentration of fluoride (Jalander, India). These teeth were stored in saturated aqueous solution at 4°C to reduce deterioration in storage. All the selected teeth were used within 3 months of extraction, as per recommendations of Occupational Safety And Health Administration (OSHA).5 Crowns were sectioned from the roots horizontally and then vertically in a bucco-lingual direction to produce 2 enamel samples from each crown. Hence, 70 samples were produced for the study. The samples were mounted on self cure acrylic resin block cured in previously cut PVC cylinder (0.95mm diameter, 5cm height) with the dentinal portion of the tooth being embedded in the acrylic block leaving 1cm of the enamel surface of the tooth as being measured by a vernier calliper exposed above the acrylic resin. The outer surface of the enamel was ground under water coolant using 400 grit, 1000 grit and 1500 grit silicon carbide paper to produce a flat and smooth surface. In order to standardize this procedure 20 strokes with each subsequent number of silicon carbide paper were given on each sample and by the same individual taking a break of 5 minutes after each 5 samples to avoid fatigue. This was done to ensure that the amount of grounding of the enamel produced and the amount offeree applied to produce it is almost the same for each sample. The same procedure was followed for the remaining samples.

Profdometry: Surface roughness of the samples was measured with the help of a stylus surface profilometer so that only samples with a stylus deflection of less than or equal to an average of ±0.3 urn were used in the study. The diamond stylus had a tip radius of 20um with a head velocity of 1 Omm/min. The force of the stylus varied linearly with deflection at a rate of 8mg/um up to maximum of lg at lOOum. 3 baseline readings were recorded for each enamel sample and the mean values were derived to represent the surface profile. Out of the 70 samples 60 had a stylus deflection of ±0.3 urn and were thus included in the study. The remaining 10 samples were discarded.

Treatment with remineralizing pastes: 20 enamel samples were randomly allocated to each of the 3 treatment groups: Group I (Prevident), Group II (Pronamel) and Group III (distilled water). In Group I (Prevident) and Group II (Pronamel) the enamel surface was covered with the help of a paint brush with an even layer of paste approximately 1mm thick which was measured with the help of a vernier calliper and then placed in a water bath containing distilled water at 37°C for 15 minutes. The paste was then removed by gentle brushing for 1 minute with a softtoothbrush. For Group III (control) the enamel specimens were placed in a water bath containing distilled water at 37°C for 15 minutes without putting any remineralising paste followed by brushing of the sample surface for 1 minute in order to standardize the procedure.

The enamel samples were then air dried for 30 seconds and taped to expose a2x2mm width of enamel. The edges of the tapes adjacent to the enamel were marked with a fine indelible marker pen so that follow up measurement of the surface roughness of the samples after the erosive challenge can be done at the same area.

Exposure to erosive challenge: 10 samples each from Group I (Prevident) were exposed to an erosive challenge of 250ml of orange juice (Group A) and water control (Group B) respectively that were stirred at a constant speed in a thermostatically controlled water bath at 37°C for 1 hour. Following this exposure, the enamel specimens were rinsed in water for 10 seconds and then air dried for 3 0 seconds. The tapes were then removed. Surface enamel loss was measured on the profilometer in triplicates, with theamountofenamelloss recorded in micrometers. Means were calculated from triplicate measurements. The same procedure was followed for Group II (Pronamel) and Group III (control). Values obtained were statistically analysed.

Results

Statistically significant mean values were obtained for different groups pretreated by Group I (Prevident), Group II (Pronamel) and Group III (control) by applying 1-way ANNOVAtest.

In erosive challenge by Group A (orange juice) and Group B (distilled water) the mean erosion caused in samples pretreated by Prevident (Group I) was lum and 0.29um, by Pronamel (Group II) was 1 59nm, 0.29,im and by control (Group III was 2>, 0.29 ,imrespectively (Table 1).

The mean erosion was maximum in samples pretreated by Group III (2um, 0.29um)fhen in Group II (1.59um, 0.29 Urn) followed by Group I (µm, 0.29µm) showing that maximum remineralization and thus prevention of dental erosion was provided by Prevident (Group I) followed by Pronamel (Group II).

A statistically significant mean difference in the reminer-alization potential of Group I (Prevident), Group II (Pronamel) in comparison to Group III (control) was seen by applying Tukey's post hoc test (Table 2). In Group A on intercomparing Group I and Group II a mean difference of -0.59um with a standard error of 0.06, Group I and Group III a mean difference of-1.01µm with a standard error of 0.06 and Group II and Group III a mean difference of -0.42(xm with a standard error of 0.06 was seen which showed that samples pre-treated by Prevident (Group I) showed lesser erosion than those pre-treated by Pronamel (Group II) on exposure to an erosive challenge by orange juice (Group A).

In Group B on intercomparing Group I and Group II a mean difference of O.OOum with a standard error of 0.003, intercomparing Group I and Group III a mean difference of O.OOfxm with a standard error of 0.003 and Group II and Group III a mean difference of O.OOfxm with a standard error of 0.003 was seen which showed that samples pre-treated by Prevident (Group I) and Pronamel (Group II) showed no difference in surface roughness on exposure to control (Group B).

Discussion

Dental erosion can be defined as dissolution of tooth by acids when the surrounding aqueous phase is under saturated with respect to tooth mineral.6 The acids may be intrinsic (regurgitated gastric acid) or extrinsic (acidic industrial vapours or dietary components such as softdrinks, pickles, acidic fruits). When the acidic challenge is acting for long enough, a clinically visible defect occurs which is mostly located coronal to the cemento-enamel junction. Continuing acid exposure may result in change in the physical properties of the remaining tooth surface resulting in a significant reduction in microhardness and thus making the softened surface more prone to mechanical impacts like tooth brushing and use of dental floss etc." Erosion makes the tooth more susceptible to dental caries also.10

In paediatric patients dental erosion causes more loss of tooth structure as compared to permanent teeth due to morphological differences like less mineralization etc. Also because of frequent consumption of acidic food and drinks by children for eg., marketed softdrinks, pure fruit juices etc., (pH< 4) erosion is becoming a frequent feature of deciduous dentition." Amaechi et al., examined the substance loss of deciduous and permanent teeth after immersion in orange juice. They found a 1.5 times greater progression of erosive lesions into the enamel of the primary dentition compared to that of the permanent dentition.12 Harding et al., found a link between frequent consump-tion offruitsquashandcarbonateddrinksandtheoccurrenceof dental erosion. In this study, 47% of 202, 5-year-old children showed dental erosion, with 21% of lesions in an advanced state (erosion affecting the dentine orpulp).13

Erosive damage to the permanent teeth occurring in child-hood may compromise the growing child's dentition for entire lifetime as these teeth are more prone to fracture at the cementoenamel junction and may require repeated and expensive restorations. As known no restoration can simulate natural tooth structure, thus there is an increased importance of universally applied preventive measures to prevent erosion like dietary advice, stimulation of salivary flowrate,useofbufferingmedicaments,particularmotiva-tion for non-destructive toothbrushing habits with a low abrasive toothpaste, use of various fluoride regimes like fluoridated mouthrinses, varnish, lozenges, pastes etc. The prognosis of all these preventive measures depends on patient compliance, thus the use of a fluoridated toothpaste instead of a regular toothpaste is abetter mode to prevent dental erosion as it exposes the patient to an adequate amount of fluoride twice a day.

Prevident and Pronamel are two recently introduced fluoridated toothpastes. Prevident contains 1.1% sodium fluoride. It is a prescription strength tooth paste and deli-vers 5000ppm fluoride. The fluoride content makes the tooth resistant to acid dissolution and also prevents dental caries. The increased fluoride content enables penetration of fluoride ions in to the enamel and promotes reminera-lisation.

Pronamel toothpaste has been specifically developed as a product for oral hygiene that protects teeth from the effects of acid wear. It's optimised fluoride formula rehardens acid softened tooth enamel to protect against acid wear. It contains fluoride (1450ppm sodium fluoride) to protect teeth against tooth decay and has a neutral pH. The low abrasive formula is suitable for daily use. Hence this study has been undertaken to examine whether a single topical application of Prevident and Pronamel would reduce enamel erosion causedby orange juice.

The various acidic drinks are juices like lemon juice, orange juice, softdrinks like Coke, Fanta, Thumbsup etc. As out of these orange juice is one of the most frequently consumed drink by children, therefore has been taken up in thisstudyforerosivechallenge.

It was shown by our results that both the pastes Prevident and Pronamel markedly increased enamel resistance to erosion by orange juice. Intercomparison of the two pastes showed that samples pre-treated by Prevident encompassed less erosion than those pre-treated by Pronamel. As Prevident contains more fluoride (5000ppm) than Pronamel (1450ppm) hence it caused more remineralisa-tion thus increasing the resistance to enamel erosion.

Lussi A et al., did a study to test the impact of Zendium, Pronamel, Prodent Rocket Power, Meridol and Signal activetoothpastesonthepreventionof erosion. They came to the conclusion that incubation in toothpaste slurries before the acid challenge seems to be favourable to prevent erosion. None of the tested toothpastes showed statistically significant better protection than another against an erosive attack.14

In another study Poggio C et al., evaluated the efficacy of 2 toothpastes, Sensodyne Pronamel and Biorepair Plus on repairing enamel erosion produced by Coca Cola, using AtomicForceMicroscopy.Theyfoundastatisticallysigni-ficant difference (P<0.01) in root mean square and maximum depth values showing that the toothpastes reduced enamel demineralization. No statistical differences in root mean square values were registered between the two toothpastes. They thus concluded that Pronamel and Bio-Repair Plus offer a degree of protection from erosive drinks.15

Similar results were seen in a study done by Jeremy Rees et al., in which they used Pronamel and tooth mousse as the remineralising pastes and found that both the pastes were able to prevent erosion from permanent teeth exposed to an erosive challenge of 0.2% citric acid. Compared to the water control the amount of surface enamel erosion was reduced by 48% in the Pronamel group and by 35% in the toothmousse group.16

Well within limitations of the study it can be concluded that Prevident has a greater remineralising potential than Pronamel and thus can prevent dental erosion more. We recommend that further studies should be conducted to test these products in aprospective randomised clinical trial.

References

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