ORIGINAL RESEARCH |
https://doi.org/10.5005/jp-journals-10015-2561 |
Assessment of Salivary Vitamin D Levels and Its Correlation with Dental Caries and Eruption Status of the Teeth
1Department of Pediatric and Preventive Dentistry, Farooqia Dental College and Hospital, Mysore, Karnataka, India
2–6Department of Pediatric and Preventive Dentistry, D A Pandu Memorial RV Dental College, Bengaluru, Karnataka, India
Corresponding Author: Rohini V, Department of Pediatric and Preventive Dentistry, Farooqia Dental College and Hospital, Mysore, Karnataka, India, Phone: +91 9986978589, e-mail: vrohini123a@gmail.com
Received: 12 December 2024; Accepted: 27 January 2025; Published on: 13 March 2025
ABSTRACT
Aim: To assess the correlation of salivary vitamin D with the severity of dental caries and the eruption status of the teeth.
Materials and methods: Eighty children who fulfilled the inclusion criteria were recruited. The permanent decayed, missing, and filled teeth/primary decayed, missing, and filled teeth (DMFT/dmft) index was recorded using oral health diagnostic criteria defined by the World Health Organization (WHO). Subjects were divided into four groups: group I: no dental caries (dmft/DMFT = 0); group II: mild dental caries (1 ≤ dmft/DMFT ≤ 2); group III: moderate dental caries (3 ≤ dmft/DMFT ≤ 4); group IV: severe dental caries (dmft/DMFT ≥ 5). The clinical eruption status was recorded using the FDI system. Vitamin D levels were measured from the salivary samples collected from subjects using enzyme-linked immunosorbent assay (ELISA).
Results: Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 22. Data from this cross-sectional study showed that dental caries and salivary vitamin D levels were inversely related, with a statistically insignificant correlation between the clinical eruption status of the teeth and salivary vitamin D levels.
Conclusion: The observations demonstrate that vitamin D may help prevent dental caries in children and provide credence to the necessity of public health campaigns that promote good oral health through sensible eating practices and exposure to sunlight.
Clinical significance: The study’s clinical value stems from its ability to determine preventive measures and improve pediatric oral health outcomes. The association between salivary vitamin D levels and dental caries allows healthcare providers to adopt preventive measures that foster good oral health.
Keywords: 25(OH)D (25 hydroxy vitamin D), Decayed, missing, filled teeth, Dental caries, Saliva, Teeth eruption, Vitamin D
How to cite this article: V R, Shankarappa PR, Anantharaj A, et al. Assessment of Salivary Vitamin D Levels and Its Correlation with Dental Caries and Eruption Status of the Teeth. World J Dent 2025;16(1):51–55.
Source of support: Nil
Conflict of interest: None
INTRODUCTION
Vitamin D is a fat-soluble vitamin. Endogenous synthesis occurs when ultraviolet (UV) photons from sunshine strike the skin and initiate vitamin D synthesis. It is also obtained through other exogenous sources.1 It is associated with a broad spectrum of biological functions, including the regulation of calcium and phosphate metabolism, development of innate immunity, and cognitive functions. The major functions of vitamin D required for oral health preservation are the mineralization of teeth and the maintenance of the structural integrity of tissues.2
The circulatory metabolite of vitamin D, 25-hydroxyvitamin D₃ (25(OH)D₃), binds to the vitamin D receptor. The receptors for vitamin D are found in the cells forming enamel and dentin, which bind to vitamin D and enhance the production of antimicrobial proteins that help fight bacteria causing dental caries.3,4 Vitamin D is essential for bone and tooth mineralization; however, if concentrations are significantly imbalanced, it may result in a rachitic tooth, a poorly formed hypomineralized structure prone to fractures and decay, thus increasing the colonization of Streptococcus mutans.5 Ultimately, the loss of vitamin D signaling pathways in tooth cells, along with low concentrations of calcium and phosphate ions, inhibits proper mineralization of teeth, leading to mineralization defects. Vitamin D deficiency also causes unclear lamina dura in primary and permanent teeth, incomplete calcification of dentin, delayed tooth eruption, and spontaneous periapical abscesses without causative factors such as dental caries, abrasion, tooth fracture, or trauma.5
A randomized trial published in the Lancet concluded that serum vitamin D deficiency during pregnancy was associated with enamel hypoplasia in offspring. Enamel hypoplasia is one of the developmental defects regarded as a major contributor to dental caries in pediatric dentistry. Long-term vitamin D insufficiency lowers systemic calcium levels and raises parathyroid hormone, which inhibits collagen matrix mineralization. If the mineralization of enamel and dentin is reduced, the likelihood of developing dental caries increases.
One possible mechanism is that vitamin D controls the generation of inflammatory cytokines, inhibits the maturation of antigen-presenting dendritic cells, and reduces the activation and proliferation of antigen-specific T cells.6 By regulating B cell proliferation and immunoglobulin synthesis, vitamin D protects against infection.6S. mutans is one of the primary causative organisms involved in the initiation of dental caries. Vitamin D-like substances have antibacterial action against both gram-positive and gram-negative bacteria.5 A study concluded that the addition of the vitamin D derivative doxercalciferol to cultures of S. mutans caused time-dependent lytic activity through a bacitracin resistance-dependent mechanism. Bacitracin inhibits dephosphorylation of C₅₅-isoprenyl pyrophosphate, thereby interfering with peptidoglycan synthesis.5 Cholecalciferol (vitamin D₃) attachment to the bacterial cell wall disrupts the wall and membrane, causing contraction, roughening, and increased internal pressure, which results in bleb-like formations and ultimately leads to cell membrane rupture and bacterial destruction.
Saliva is also known as the “mirror of the body.” It serves as a novel investigative aid for monitoring overall health and detecting the onset of certain disorders. Saliva is an intricate combination of inorganic and organic elements such as proteins, mucinous compounds, and antimicrobial elements. It plays a crucial role in maintaining pH balance, lubrication, antibacterial activity, and immunological function. As it flows across the teeth and oral mucosa, saliva reflects and controls the physiological equilibrium of minerals and nutrients in the oral cavity. Because it is readily accessible and contains a wide range of secretory substances, saliva has been utilized for immune-mediated and metabolic testing.6
Dental development is also associated with the rate of general maturation, which exhibits significant variation within the community. Dental age has been assessed based on the eruption and formation of dental tissues.7 The gradual transition of a tooth within the alveolus toward functional occlusion is represented by eruption, whereas mineralization depicts the process of tooth formation from the initial development of a cusp to the apical completion of the root. Therefore, chronological age is not a precise method for assessing tooth calcification stages. Vitamin D deficiency is one of the risk factors that can lead to delayed tooth development and maturation.7 Studies have shown a correlation between serum vitamin D levels, dental caries, and salivary vitamin D.8 However, there is a paucity of studies assessing the correlation of salivary vitamin D with dental caries and the eruption status of teeth. Thus, this study aims to correlate salivary vitamin D levels with dental caries and the eruption status of teeth in mixed dentition.
MATERIALS AND METHODS
Study Design
The present cross-sectional study was carried out from November 2022 to December 2023 in Bengaluru, Karnataka, India. The study was approved by the Research Sustenance and Institutional Review Board Committee of D A Pandu Memorial RV Dental College, Karnataka (IRB-388/vol-2/2021). The power of the study was calculated to be 80%, and a total of 60 subjects were selected from the Department of Pediatric and Preventive Dentistry, D A Pandu Memorial RV Dental College, Bengaluru. The study procedure was explained in detail, and written informed consent was obtained from all participants. The research was conducted in accordance with the 1975 Helsinki Declaration, as revised in 2013. The study population was divided into four groups based on the permanent decayed, missing, and filled teeth/primary decayed, missing, and filled teeth (DMFT/dmft) score of subjects:
Group I: Children without dental caries (dmft/DMFT = 0; n = 20).
Group II: Children with mild dental caries (1 ≤ dmft/DMFT ≤ 2; n = 20).
Group III: Children with moderate dental caries (3 ≤ dmft/DMFT ≤ 4; n = 20).
Group IV: Children with severe dental caries (dmft/DMFT ≥ 5; n = 20).
The inclusion criteria for the study population were:
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Children without any systemic illness.
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Children within the age-group of 9–12 years.
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Children with parental consent.
The exclusion criteria for all four groups were:
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Children with systemic diseases or chronic illness.
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Children on vitamin D and calcium supplementation.
Parameters Assessed
Demographic variables such as age and sex were noted. On intraoral examination, DMFT/dmft scores of the subjects were recorded using diagnostic instruments according to World Health Organization (WHO) criteria (2013) for dental caries. Teeth present in the oral cavity were recorded using the FDI system.
Saliva Sample Collection
Two milliliters of unstimulated whole saliva samples were collected using the spitting method. Participants refrained from eating or drinking for an hour before sample collection. The samples were collected between 9:00 AM and 11:00 AM to minimize the effects of diurnal variation. The collected samples were stored at a temperature of 4°C in Eppendorf tubes and transferred to the laboratory. The samples were then centrifuged for 10 minutes at 4°C to eliminate debris and squamous cells, after which the levels of 25(OH)D were assayed.
Estimation of Salivary Vitamin D Using Enzyme-linked Immunosorbent Assay
The determination of salivary vitamin D levels was performed using a sandwich enzyme-linked immunosorbent assay kit (Kinesis Dx) according to the manufacturer’s instructions (Krishgen Biosystems, Mumbai, India). Optical density (OD) was measured for each well using a microplate reader set to 450 nm.
Statistical Analysis
Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software (IBM SPSS Statistics for Windows, Version 22.0, Armonk, NY: IBM Corp., 2013). To compare the mean salivary vitamin D values between various levels of caries activity groups and the clinical eruption status of the teeth, the Kruskal–Wallis test was applied, followed by Dunn’s post hoc test for multiple groupwise comparisons.
RESULTS
Mean salivary vitamin D levels in group I were 46.143 ± 11.903, in group II were 35.850 ± 10.382, in group III were 24.650 ± 9.089, and in group IV were 12.710 ± 7.644. On intergroup comparison, the mean salivary vitamin D levels between the different groups were statistically significant at p < 0.001 (Fig. 1). Multiple comparisons of mean differences between groups demonstrated that group IV had significantly lower mean salivary vitamin D levels compared to group III, group II, and group I at p = 0.002 and p < 0.001, respectively. Group III showed lower mean salivary vitamin D levels compared to group I and group II at p < 0.001 and p = 0.003, which was statistically significant (Table 1). Finally, mean salivary vitamin D levels in group II were significantly lower compared to group I at p = 0.008. Mean salivary vitamin D levels in group I, compared to groups III and IV, were statistically significant at p < 0.001. Mean salivary vitamin D levels in group II, compared to group IV, were statistically significant at p < 0.001. This indicates that the mean salivary vitamin D levels were highest in group I, followed by groups II and III, and lowest in group IV.
| (I) Groups | (J) Groups | Mean diff. (I–J) | 95% CI for the diff. | p-value | |
|---|---|---|---|---|---|
| Lower | Upper | ||||
| Group I | Group II | 10.293 | 2.085 | 18.500 | 0.008* |
| Group III | 21.493 | 13.285 | 29.700 | <0.001* | |
| Group IV | 33.433 | 25.225 | 41.640 | <0.001* | |
| Group II | Group III | 11.200 | 2.992 | 19.408 | 0.003* |
| Group IV | 23.140 | 14.932 | 31.348 | <0.001* | |
| Group III | Group IV | 11.940 | 3.732 | 20.148 | 0.002* |
*Critical value of p is considered to be < 0.05
Fig. 1: Mean salivary vitamin D levels (ng/mL) among the four study groups
The mean salivary vitamin D levels in group I (Fig. 2) for the tooth 15 unerupted group were 45.390 ± 11.175, for the partially erupted group were 22.067 ± 6.154, and for the completely erupted group were 54.983 ± 3.785. The difference in mean salivary vitamin D levels based on the clinical eruption status of tooth 25 in group I was statistically significant at p = 0.04. Multiple comparisons of mean differences between groups using Dunn’s post hoc test demonstrated that the partially erupted group had significantly lower mean salivary vitamin D levels compared to the unerupted and completely erupted groups at p = 0.04. However, no significant differences were observed in mean salivary vitamin D levels based on the clinical eruption pattern (Fig. 3) of other teeth in group I or in other study groups.
Fig. 2: Mean salivary vitamin D levels based on the clinical eruption status of different teeth in the upper right quadrant in groups I and II
Fig. 3: Mean salivary vitamin D levels based on the clinical eruption status of different teeth in the upper right quadrant in groups III and IV
Within the limitations of this study, it can be inferred that salivary vitamin D could influence dental caries activity but not the clinical eruption pattern of the teeth. Thus, optimum levels of salivary vitamin D decrease the risk of dental caries in children.
DISCUSSION
Vitamin D plays a crucial role in odontogenesis. Understanding the relationship between vitamin D and tooth decay is vital to determining the prevalence of dental caries in children. This information is crucial for implementing preventive strategies and promoting optimal oral health. By emphasizing the importance of vitamins in maintaining healthy teeth, healthcare providers may help reduce dental caries activity and improve children’s overall health globally. This study aimed to compare salivary vitamin D levels with dental caries and the clinical eruption status of the teeth.
Saliva was chosen as the biological fluid to assess vitamin D levels because it is simple to collect without the need for specialized professional training. Additionally, passive diffusion or active transport of salivary components such as vitamins and cytokines, which are derivatives of blood and salivary glands, occurs without being significantly affected by changes in the salivary glands.3,6 Therefore, saliva can reflect blood levels of vitamins and serve as a biomarker for assessing vitamin D levels.
In this study, dental caries assessment was conducted using a mouth mirror according to World Health Organization (WHO) criteria, and caries experience was recorded using the decayed, missing, and filled teeth index (dmft). The decayed, missing, and filled teeth (DMFT) index has been the standard and most widely used measure globally for assessing the prevalence of decayed, missing, and filled teeth for >50 years. Unerupted teeth, congenitally missing teeth, supernumerary teeth, and teeth extracted for conditions other than dental caries were not considered in DMFT index recording. The missing teeth (M) component was not included in this study, as the teeth may have been extracted due to preshedding mobility.
According to this study, mean salivary vitamin D levels in group I were 46.143 ± 11.903, in group II were 35.850 ± 10.382, in group III were 24.650 ± 9.089, and in group IV were 12.710 ± 7.644. This difference in mean salivary vitamin D levels between the four groups was statistically significant at p < 0.001. Higher levels of vitamin D in saliva occur due to the release of larger amounts of vitamin D₃ binding proteins in saliva.9 Caries-free children are likely to have an optimal serum vitamin D concentration of 75–100 nmol/L.10,11 Studies comparing the association between serum vitamin D levels and dental caries have found a significant inverse correlation, which aligns with the results of this study.12,14
In this study, in group I, the clinical eruption status of Tooth 25 was statistically significant at p = 0.04 with salivary vitamin D. This might be due to the fact that tooth development is a continuous process, whereas the patients’ vitamin D levels were assessed only at a specific point in time. Several studies reveal that tooth development varies across communities, and these discrepancies occur not only across different cultures worldwide but also within localities in the same nation.15 External factors such as infection, extraction, crowding, and ankylosis affect tooth eruption. Alterations in dental maturation have been attributed to genetic effects, socioeconomic background, nutritional status, dietary patterns across various communities, ethnographic groups, and subgroups within a given community.16
Vitamin D receptor polymorphisms are independent of variations in dental age, which is assessed based on panoramic radiographs and intraoral examinations.17 Since dental development is a continuous process, but vitamin D was measured only at a specific point in time in this study, this might be a limitation. Factors such as sun exposure, outdoor activity, and other environmental influences were not considered, which are additional limitations of this study. However, further large-scale longitudinal studies with a larger sample size and multicentric sampling are needed to substantiate the molecular mechanisms of vitamin D’s effects on tooth eruption. This study provides insight into the potential role of salivary vitamin D in the progression of dental caries in children.
CONCLUSION
Mean salivary vitamin D levels in children without dental caries were significantly higher than in children with caries. Therefore, there is a negative correlation between salivary vitamin D levels and dental caries status. However, there was no statistically significant correlation between salivary vitamin D levels and the eruption status of the teeth. A few teeth showed a positive correlation between salivary vitamin D levels and eruption status. Thus, it can be stated that the eruption of teeth is not directly influenced by vitamin D levels in saliva.
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