|Year : 2015 | Volume
| Issue : 4 | Page : 291-295
Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis
Saranya Mony1, Arathi Rao1, Ramya Shenoy2, Baranya Srikrishna Suprabha1
1 Department of Paedodontics and Preventive Dentistry, Manipal College of Dental Sciences, Manipal University, Mangalore, Karnataka, India
2 Department of Public Health Dentistry, Manipal College of Dental Sciences, Manipal University, Mangalore, Karnataka, India
|Date of Web Publication||18-Sep-2015|
Dr. Arathi Rao
Department of Paedodontics and Preventive Dentistry, Manipal College of Dental Sciences, Manipal University, Light House Hill Road, Mangalore - 575 001, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Calcium sodium phosphosilicate (NovaMin) is an agent that is claimed to release calcium and phosphate ions intraorally to help the self-repair process of enamel. It is used extensively as a desensitizing agent, but the chemical reactions that occur may promote apatite formation enhancing remineralization. The present study was undertaken to evaluate the ability of NovaMin to remineralize an experimentally induced demineralized lesion. The evaluation was done based on the quantitative and qualitative analysis of enamel over the period of 15 and 30 days. Materials and Methods: A sample of 120 noncarious premolar teeth extracted for orthodontic reasons were used for the study. Baseline data for hardness, Ca/PO 4 , and surface characteristics before and after demineralization process was obtained. All the teeth were brushed twice daily at 12 h interval with the test agents using a powered toothbrush for 2 min. The samples were tested on the 15 th and 30 th day. Results: Calcium phosphate ratio and hardness in both the groups improved during the study period. Fluoride group showed higher values for Ca/PO 4 and hardness but was not statistically significant with the P > 0.05. Scanning electron microscope pictures showed that the deposition of the material over the decalcified enamel is more smoother and uniform with NovaMin and more irregular with fluoride. Relevance: NovaMin is found to be as effective in improving the Ca/PO 4 ratio and hardness in a demineralized enamel as fluoride. Hence, it can be a new alternate material for remineralization of enamel with less toxic effects compared to fluorides.
Keywords: Fluoride, NovaMin, remineralization
|How to cite this article:|
Mony S, Rao A, Shenoy R, Suprabha BS. Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis. J Indian Soc Pedod Prev Dent 2015;33:291-5
|How to cite this URL:|
Mony S, Rao A, Shenoy R, Suprabha BS. Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis. J Indian Soc Pedod Prev Dent [serial online] 2015 [cited 2018 Dec 10];33:291-5. Available from: http://www.jisppd.com/text.asp?2015/33/4/291/165667
| Introduction|| |
Dental caries is considered as a dynamic process intervened by cycles of demineralization and remineralization several decades ago, it was noted that clinically detectable white-spot lesions could be hardened or involuted. , Various scientific methods have been advocated for arrest and the reversal of incipient caries lesion by either decreasing the solubility of the mineral present or by increasing the mineral content of the previously demineralized tooth.  Fluoride is one of the historic agents that is used for remineralization of incipient caries or prevention of new carious lesion.  It strengthens teeth against decay by promoting the uptake of calcium and phosphate from saliva and other sources into the enamel (remineralization) forming a new substance, fluorapatite (FAP), on the tooth surface which is more resistant to plaque acids than the enamel's original hydroxyapatite. 
Calcium sodium phosphosilicate (NovaMin) is a new agent that is claimed to release calcium and phosphate ions intraorally to help the self-repair process of enamel.  A silica-rich surface layer forms through polycondensation of hydrated silica groups on which precipitation of ions happens which crystallizes over time to form a hydroxyl-carbonate apatite. Although it is used extensively as a desensitizing agent reports also claim that the chemical reactions that promote apatite formation may enhance the remineralization. 
In view of the remineralization potential of NovaMin, the present study was undertaken to assess whether NovaMin can be used as an effective remineralizing agent compared to the traditionally used fluoride, in an experimentally induced caries like lesion. The null hypothesis was assumed that there is no difference between the two groups. The evaluation was done based on the hardness, mineral content (CaPO 4 ratio), and scanning electron microscope (SEM) appearance.
| Materials and Methods|| |
This study was conducted after obtaining consent from the Institutional Ethics Committee.
NovaMin toothpaste (Dr. Collins Restore™ Toothpaste, USA) and Fluoride toothpaste (Colgate-Palmolive, India containing sodium monofluorophosphate) were used for the study. A sample of 120 noncarious premolar teeth extracted for orthodontic reasons was used for the study. Teeth with visible cracks, erosion, developmental anomalies or restoration were excluded.
The crown portion of the tooth were subjected to prophylaxis with pumice slurry using a rubber polishing cup for a minute and washed thoroughly with distilled water. The samples were grouped into two (60 each) for testing the mineral content (CaPO 4 ratio) and hardness, respectively. Each of the groups was further divided into three subgroups (Baseline, NovaMin, and Fluoride groups) of 20 samples each. Twenty samples in the baseline subgroup were used to check the hardness and mineral content of sound enamel before demineralization. The remaining teeth were then subjected to demineralization by immersing in the modified Ten Cate's demineralizing solution  (calcium 2.2 mmol, phosphate 2.2 mmol, fluoride 5 mmol, with a pH of 3.75) for a time period of 2 days. The demineralization was confirmed visually and under a magnifying glass. Teeth were brushed with powered toothbrush and their respective pastes for 2 min twice daily at 12 h interval. Each time after brushing, the samples were immersed in artificial saliva at room temperature, which was replenished every 24 h.
The pH cycling was done once daily for all samples. Each cycle involved 1.5 h of demineralization by immersing them in a demineralizing bath followed by remineralization for 1 h with an agent composed of sodium carbonate 20 mmol, phosphate 3.3 mmol, calcium 1 mmol with pH 7. The samples were placed in Fusayama Meyer's artificial saliva  (KCl 0.4 g/l, NaCl 0.4 g/l, CaCl 2·2H 2 O 0.906 g/l, NaH 2 PO 4·2H 2 O 0.690 g/l, Na 2 S·9H 2 O 0.005 g/l, urea 1 g/l; pH 6.5) in between the pH cycling periods.
Samples were then embedded in an acrylic block for easy handling during testing.
Vicker's hardness testing (VHN) (microhardness) was done on the samples embedded in the acrylic block. The testing was done with a Matsuzava digital microhardness tester, Japan. The software used for measurement was Clemex software designed by Matsuzava. The sample was placed on a stage after leveling the acrylic block so that a plane is achieved. The diamond tip that was used to create a nanoindent had a hardness value of 8000 VHN. Under a ×400 using the digital optical microscope, the sample positioning was done so that the indent falls on the enamel portion of the section. A load of 50 gf for 10 s was applied, and the rhomboid indent is measured for length, and depth digitally and the hardness value were calculated.
Mineral content analysis by scanning electron microscope-energy dispersive X-ray
The samples were dried in a hot air oven (Heatron industrial heaters, India) at 110°C for 15 min. The samples were ensured to be moisture free, and care was taken to avoid any direct contact with air or moisture. These samples were covered in a carbon paper and placed on the metal mounting block, then sputtered with gold in a vacuum closed container (JFC 1600 Auto Fine Coater, Tokyo, Japan) at high temperature. These samples were then analyzed using an SEM and energy dispersive X-ray Analysis at ×27 and energy 20 KeV for mineral content and surface changes. The images were obtained with a ×2000 for comparison.
Statistical analysis was done using the software SPSS (version 11.5). The mineral content and hardness values enamel after treating with NovaMin and fluoride groups were entered in the SPSS (SPSS South Asia Pvt.Ltd.) software for statistical analysis, and the descriptive statistics were calculated. The repeated measures of ANOVA were applied to assess the statistical significance, which was established at P < 0.05.
| Results|| |
The present in vitro study was conducted to evaluate the remineralizing efficacy of Novamin toothpaste, a novel calciumphosphosilicate formulation. The objective of the study was to evaluate the remineralizing efficacy on an artificially induced white-spot lesion in comparison with fluoride for the same. The parameters, which were considered includes microhardness of tooth enamel, calcium and phosphate content of the tooth sample and surface smoothness of the enamel.
The descriptive statistics of NovaMin and fluoride group have been tabulated in [Table 1]. The calcium phosphate ratio in both the groups improved during the study period. However, the ratio did not reach the sound enamel level, except in the 30 days fluoride group the Ca/PO 4 reached the sound enamel level.
|Table 1: Descriptive statistics showing mineral content and hardness value after demineralization, after 15 days and after 30 days in NovaMin and Fluoride groups|
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Following demineralization there was a considerable fall in the hardness level of the enamel by about 105.2-108.58. In both the groups, the hardness improved considerably but did not reach the level of the sound enamel.
When the analysis was carried out separately for the groups, both NovaMin and fluoride groups showed a statistical significant difference in Ca/PO 4 ratio and hardness values [Table 2]. Hence, we can conclude Ca/PO 4 and hardness values of the demineralized tooth have been increased after application of NovaMin and fluoride. Even though fluoride group showed higher values for Ca/PO 4 and hardness, the comparison of Ca/PO 4 and hardness values between NovaMin and Flouride group did not show any statistical significance with the P > 0.05. Details of the tests were tabulated in [Table 3]. As there was no statistical significance to increase Ca/PO 4 and hardness values of the demineralized tooth after treating with NovaMin and fluoride, we can say that NovaMin is as effective in improving the Ca/PO4 ratio and hardness in a demineralized enamel as fluoride.
|Table 2: Comparison of mineral content and hardness in NovaMin and Fluoride as a individual groups, after demineralization, after 15 days and after 30 days as in repeated measures of ANOVA|
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|Table 3: Comparison of mineral content between NovaMin and Fluoride groups after demineralization, after 15 days and after 30 days|
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Scanning electron microscope images interpretation
Normal enamel structure has a fish scale appearance in longitudinal section. Following demineralization, rods collapse due to lack of proper orientation of the hydroxylapatite crystals and the fish scale appearance disappears [Figure 1]a and b.
|Figure 1: (a) Scanning electron microscope structure of sound enamel surface. (b) Scanning electron microscope structure enamel surface after demineralization|
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[Figure 2] shows the surface changes in the enamel after remineralization with NovaMin. The deposition of the material over the decalcified enamel is more smoother and uniform. The increase in thickness being reconfirmed by areas in enamel seen as dark areas which suggest depth is a dimension.
|Figure 2: Scanning electron microscope structure of surface changes following remineralization with NovaMin|
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The images of enamel surface treated with fluoride shows filling up of the rods and interrod regions with FAP layer, which are seen as globular regions [Figure 3]. FAP crystals appear more irregular, and the defects are not uniformly covered.
|Figure 3: Scanning electron microscope structure of surface changes following remineralization with Fluoride|
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| Discussion|| |
The present study investigated the in vitro effect of two commercially available toothpaste formulations containing NovaMin and fluoride, on surface microhardness, Ca/PO 4 , and structural changes in an intentionally created early enamel caries lesions.
Clinical evidence suggests that fluoride is effective in preventing caries onset and arresting or possibly reversing the process of demineralization. Although the remineralizing efficacy of fluoride is substantially justified, the material is not able to surpass the high caries challenge posed in few individuals, and this highlights the need to find newer methods to enhance remineralization process. The availability of calcium in the oral environment is a key requisite in the remineralization of enamel and dentin. This has led to the development of various calcium based systems that enhance the availability of calcium and phosphate. 
The NovaMin technology was developed by Dr. Len Litkowski and Dr. Gary Hack. Originally it was used to treat hypersensitivity of dentin. Recently, it is also tried as a remineralizing agent. 
It is calcium sodium phosphosilicate bioactive glass, which is chemically reactive in extracellular body fluids, releasing sodium, calcium, phosphate, and soluble silica from its network structure.  This unique material has numerous novel features, most important of which is its ability to act as a biomimetic mineralizer matching body's own mineralizing traits, which also affects cell signals in a way that benefits the restoration of tissue structure and function. It is considered as a breakthrough in remineralization because current systems are dependent on adequate saliva as a source of calcium and phosphate, but bioactive glasses are enriched with these ions. 
Vickers method was chosen in the present study because the square shaped indent obtained was more easy and accurate to measure and detect visually and digitally.  The average hardness Value of enamel is in the range of 250-360 VHN.  In the present study, the value obtained had a mean of 326.32 ± 25.30 standard deviation (SD), which was within the above-mentioned range. The hardness value fell significantly following demineralization (193.2 + 33.83 SD).
In both the groups increase in microhardness was noticed following remineralization and the recovery of microhardness in both the groups at the end of 30 days of remineralization. Fluoride achieved better hardness compared to NovaMin. However, Vahid Golpayegani et al.  found superior surface hardness with NovaMin compared to fluoride. However, the outcome was not statistically significant in both the studies.
The calcium and phosphate levels in both the groups increased following remineralization and reaching the baseline level with fluoride. The mineral quantification studies by Lippert  showed that the calcium and phosphorous exhibited fluctuation in levels after demineralization and remineralization. The differences in microhardness recovery and mineral content variation of the two dentrifices were attributed to their variation in mode of action.  When introduced into the oral environment, NovaMin releases sodium, calcium, and phosphate ions, which then interact with oral fluids and result in the formation of a crystalline hydroxycarbonate apatite (HCA) layer that is structurally and chemically similar to natural tooth mineral. 
Fluoride-promoted remineralization of a white-spot lesion is based on the formation of fluoride-rich apatite due to increased F - Intake due to the porous surface of the demineralized enamel when fluoride is present, demineralized crystals serve as nuclei for the accumulation of new mineral and the result is a fluoride-rich, carbonate-poor, acid-resistant surface mineral layer, the fluorhydroxyapatite and FAP. 
The surface topographic changes analyzed by SEM show that the enamel surface treated by NovaMin showed a much smoother and uniform surface compared to that of fluoride. Madan et al.  had described that bioactive glasses form a surface carbonated hydroxyapatite layer 100-150 micron thick in 12-24 h. NovaMin is said to replace the mineral content of the white-spot lesions in the form of HCA, which has a chemical structure similar to that of the enamel crystals, thereby almost reproducing the layer of enamel that was lost. The crystals are indistinguishable from normal enamel when formed on the surface as it is unstained and very white. It has been microscopically seen as small, disorganized crystallites. Scientific evidence in the literature regarding the remineralization efficacy of NovaMin on incipient lesions is very few. 
The most important property of calcium phosphate or calcium fluoride materials is their solubility behavior. The majority of the calcium systems are insoluble. Differences in the calcium concentration have important implications for the possibility of remineralization because under low calcium concentrations remineralization will not occur. Novamin system provides low levels of bioavailable calcium and phosphate ions, which will supersaturate saliva and helps in precipitation of these ions on the tooth surface. 
Novamin thus appears as an effective remineralizing agent as fluoride for white-spot remineralization. ,,
| Conclusion|| |
The following conclusions were drawn from the study:
- Novamin effectively enhances the process of remineralization as shown by the increase in hardness value and Ca/PO 4 .
- Surface changes following remineralization by NovaMin exhibits uniform surface characteristics as shown in SEM images.
- NovaMin is as effective as fluoride in producing remineralization of early carious lesions when used in the form of a paste as fluoride.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]