Iron level participates in the pathological damages of dental caries in infant rats by affecting enamel mineralization

Iron deficiency anemia (IDA) is a common nutritional disease associated with early childhood caries. This study aimed to explore the role of iron levels in pathological changes of dental caries in childhood. Rats were divided into four groups based on their iron content: IDA, positive control (PC), high iron (HI), and negative control (NC). Except for the rats in the NC group, rats in the other groups were inoculated with Streptococcus mutans and fed cariogenic high-sugar fodder to induce caries. Three months later, the caries status of the molars was evaluated at both the smooth and sulcal surfaces according to Keyes scores. Scanning electron microscopy (SEM) was performed to reveal microstructural changes in caries. Energy-dispersive spectroscopy (EDS) was used to determine the elemental composition of the enamel and dentin. In addition, the histopathology of the salivary gland was detected using hematoxylin and eosin (HE) staining.The results showed that rats in the PC group exhibited obvious carious lesions. The carious score was significantly higher in the IDA group than in the PC group but was lower in the HI group. SEM revealed complete destruction of the enamel and damage to the middle dentin in the IDA group. In contrast, the molars in the HI group exhibited some degree of enamel demineralization, but the underlying dentin was almost intact. In addition, the elemental compositions of the enamel and dentin were similar among the four groups, and iron was detected only in the HI group. No differences were observed in the morphological structures of the salivary glands of rats from the different groups. In conclusion, ID enhanced the pathological damage of caries, whereas HI weakened it. Iron may participate in the pathological damage caused by childhood caries by affecting enamel mineralization.

Caries; Children; Iron; Enamel demineralization; Salivary gland

[1] Pitts NB, Zero DT, Marsh PD, Ekstrand K, Weintraub JA, Ramos-Gomez F, et al. Dental caries. Nature Reviews. Disease Primers. 2017; 3: 17030.

[2] Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown Z, et al. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990–2015: a systematic analysis for the global burden of disease study 2015. The Lancet. 2016; 388: 1545–1602.

[3] Low M, Farrell A, Biggs B, Pasricha S. Effects of daily iron supplementation in primary-school-aged children: systematic review and meta-analysis of randomized controlled trials. Canadian Medical Association Journal. 2013; 185: E791–E802.

[4] Reddy V, Reddy V, Krishna Kumar RVS, Sudhir K, Srinivasulu G, Deepthi A. Dental caries experience in relation to body mass index and anthropometric measurements of rural children of Nellore district: a cross-sectional study. Journal of the Indian Society of Pedodontics and Preventive Dentistry. 2019; 37: 12–17.

[5] Clarke M, Locker D, Berall G, Pencharz P, Kenny DJ, Judd P. Malnourishment in a population of young children with severe early childhood caries. Pediatric Dentistry. 2006; 28: 254–259.

[6] Schroth RJ, Harrison RL, Moffatt MEK. Oral health of indigenous children and the influence of early childhood caries on childhood health and well-being. Pediatric Clinics of North America. 2009; 56: 1481–1499.

[7] Easwaran HN, Annadurai A, Muthu MS, Sharma A, Patil SS, Jayakumar P, et al. Early childhood caries and iron deficiency anaemia: a systematic review and meta-analysis. Caries Research. 2022; 56: 36–46.

[8] Hesse D, Bonifácio CC. Is there an association between early childhood caries and iron deficiency anaemia? Evidence-Based Dentistry. 2022; 23: 146–147.

[9] Ji S, Han R, Huang P, Wang S, Lin H, Ma L. Iron deficiency and early childhood caries: a systematic review and meta-analysis. Chinese Medical Journal. 2021; 134: 2832–2837.

[10] Hwang G, Marsh G, Gao L, Waugh R, Koo H. Binding force dynamics of streptococcus mutans-glucosyltransferase B to candida albicans. Journal of Dental Research. 2015; 94: 1310–1317.

[11] Bowen WH, Koo H. Biology of Streptococcus mutans-derived glucosyl-transferases: role in extracellular matrix formation of cariogenic biofilms. Caries Research. 2011; 45: 69–86.

[12] Leme AFP, Koo H, Bellato CM, Bedi G, Cury JA. The role of sucrose in cariogenic dental biofilm formation—new insight. Journal of Dental Research. 2006; 85: 878–887.

[13] Berlutti F, Ajello M, Bosso P, Morea C, Andrea P, Giovanni A, et al. Both lactoferrin and iron influence aggregation and biofilm formation in Streptococcus mutans. BioMetals. 2004; 17: 271–278.

[14] Pecharki GD, Cury JA, Paes Leme AF, Tabchoury CPM, Del Bel Cury AA, Rosalen PL, et al. Effect of sucrose containing iron (II) on dental biofilm and enamel demineralization in situ. Caries Research. 2005; 39: 123–129.

[15] Keyes PH. Dental caries in the molar teeth of rats I. Distribution of lesions induced by high-carbohydrate low-fat diets. Journal of Dental Research. 1958; 37: 1077–1087.

[16] Keyes PH. Dental caries in the molar teeth of rats II. A method for diagnosing and scoring several types of lesions simultaneously. Journal of Dental Research. 1958; 37: 1088–1099.

[17] Paradella TC, Koga-Ito CY, Jorge AO. Ability of different restorative materials to prevent in situ secondary caries: analysis by polarized light-microscopy and energy-dispersive X-ray. European Journal of Oral Sciences. 2008; 116: 375–380.

[18] Nam K, Dos Santos HT, Maslow F, Tump BG, Lei P, Andreadis ST, et al. Laminin-1 peptides conjugated to fibrin hydrogels promote salivary gland regeneration in irradiated mouse submandibular glands. Frontiers in Bioengineering and Biotechnology. 2021; 9: 729180.

[19] Lasisi TJ, Shittu ST, Oguntokun MM, Tiamiyu YA. Aging affects morphology but not stimulated secretion of saliva in rats. Annals of Ibadan Postgraduate Medicine. 2014; 12: 109–114.

[20] Kazeminia M, Abdi A, Shohaimi S, Jalali R, Vaisi-Raygani A, Salari N, et al. Dental caries in primary and permanent teeth in children’s worldwide, 1995 to 2019: a systematic review and meta-analysis. Head & Face Medicine. 2020; 16: 22.

[21] Sharifi R, Tabarzadi MF, Choubsaz P, Sadeghi M, Tadakamadla J, Brand S, et al. Evaluation of serum and salivary iron and ferritin levels in children with dental caries: a meta-analysis and trial sequential analysis. Children. 2021; 8: 1034.

[22] Al-Ani AH, Antoun JS, Thomson WM, Merriman TR, Farella M. Hypodontia: an update on its etiology, classification, and clinical management. BioMed Research International. 2017; 2017: 9378325.

[23] Lan Y, Jia S, Jiang R. Molecular patterning of the mammalian dentition. Seminars in Cell & Developmental Biology. 2014; 25–26: 61–70.

[24] Wagle M, D’Antonio F, Reierth E, Basnet P, Trovik TA, Orsini G, et al. Dental caries and preterm birth: a systematic review and meta-analysis. BMJ Open. 2018; 8: e018556.

[25] Wang F, Lv H, Zhao B, Zhou L, Wang S, Luo J, et al. Iron and leukemia: new insights for future treatments. Journal of Experimental & Clinical Cancer Research. 2019; 38: 406.

[26] Camaschella C. Iron-deficiency anemia. The New England Journal of Medicine. 2015; 373: 485–486.

[27] Li Q, Liang F, Liang W, Shi W, Han Y. Prevalence of anemia and its associated risk factors among 6-months-old infants in Beijing. Frontiers in Pediatrics. 2019; 7: 286.

[28] Costa EM, Azevedo JAP, Martins RFM, Alves CMC, Ribeiro CCC, Thomaz EBAF. Anemia and dental caries in pregnant women: a prospective cohort study. Biological Trace Element Research. 2017; 177: 241–250.

[29] Martinhon CCR, de Moraes Italiani F, de Magalhães Padilha P, Bijella MFTB, Delbem ACB, Buzalaf MAR. Effect of iron on bovine enamel and on the composition of the dental biofilm formed “in situ”. Archives of Oral Biology. 2006; 51: 471–475.

[30] Buzalaf MAR, de Moraes Italiani F, Kato MT, Martinhon CCR, Magalhães AC. Effect of iron on inhibition of acid demineralisation of bovine dental enamel in vitro. Archives of Oral Biology. 2006; 51: 844–848.

[31] Sadeghi M, Darakhshan R, Bagherian A. Is there an association between early childhood caries and serum iron and serum ferritin levels? Dental Research Journal. 2012; 9: 294–298.

[32] Prentice A. Calcium in pregnancy and lactation. Annual Review of Nutrition. 2000; 20: 249–272.

[33] Salvolini E, Giorgio R, Curatola A, Mazzanti L, Fratto G. Biochemical modifications of human whole saliva induced by pregnancy. British Journal of Obstetrics and Gynaecology. 1998; 105: 656–660.

[34] Conde-Agudelo A, Belizan JM. Risk factors for pre-eclampsia in a large cohort of Latin American and Caribbean women. BJOG. 2000; 107: 75–83.

[35] Eshghi A, Kowsari-Isfahan R, Rezaiefar M, Razavi M, Zeighami S. Effect of iron containing supplements on rats’ dental caries progression. Journal of Dentistry. 2012; 9: 14–19.

[36] Alves KMRP, Franco KS, Sassaki KT, Buzalaf MAR, Delbem ACB. Effect of iron on enamel demineralization and remineralization in vitro. Archives of Oral Biology. 2011; 56: 1192–1198.

[37] Kato MT, de Carvalho Sales-Peres SH, Buzalaf MAR. Effect of iron on acid demineralisation of bovine enamel blocks by a soft drink. Archives of Oral Biology. 2007; 52: 1109–1111.

[38] Kato MT, Maria AG, Sales-Peres SHDC, Buzalaf MAR. Effect of iron on the dissolution of bovine enamel powder in vitro by carbonated beverages. Archives of Oral Biology. 2007; 52: 614–617.

[39] Bueno M, Marsicano J, Sales-Peres S. Preventive effect of iron gel with or without fluoride on bovine enamel erosion in vitro. Australian Dental Journal. 2010; 55: 177–180.

[40] Emilson CG, Krasse B. The effect of iron salts on experimental dental caries in the hamster. Archives of Oral Biology. 1972; 17: 1439–1443.

[41] Miguel JC, Bowen WH, Pearson SK. Effects of iron salts in sucrose on dental caries and plaque in rats. Archives of Oral Biology. 1997; 42: 377–383.

[42] Rosalen PL, Pearson SK, Bowen WH. Effects of copper, iron and fluoride co-crystallized with sugar on caries development and acid formation in deslivated rats. Archives of Oral Biology. 1996; 41: 1003–1010.

[43] Velusamy SK, Markowitz K, Fine DH, Velliyagounder K. Human lactoferrin protects against Streptococcus mutans-induced caries in mice. Oral Diseases. 2016; 22: 148–154.

[44] Fine DH. Lactoferrin: a roadmap to the borderland between caries and periodontal disease. Journal of Dental Research. 2015; 94: 768–776.

[45] Agarwal S, Pandit IK, Srivastava N, Gugnani N. Genetic engineering and dental caries. Indian Journal of Dental Research. 2003; 14: 284–288.

[46] Tschoppe P, Wolgin M, Pischon N, Kielbassa AM. Etiologic factors of hyposalivation and consequences for oral health. Quintessence International. 2010; 41: 321–333.

[47] Wu Y, Wang Y, Chang JY, Cheng S, Chen H, Sun A. Oral manifestations and blood profile in patients with iron deficiency anemia. Journal of the Formosan Medical Association. 2014; 113: 83–87.

[48] Mahantesha T, Reddy KM, Kumar NH, Nara A, Ashwin D, Buddiga V. Comparative study of probiotic ice cream and probiotic drink on salivary streptococcus mutans levels in 6–12 years age group children. Journal of International Oral Health. 2015; 7: 47–50.

[49] Animireddy D, Reddy Bekkem V, Vallala P, Kotha S, Ankireddy S, Mohammad N. Evaluation of pH, buffering capacity, viscosity and flow rate levels of saliva in caries-free, minimal caries and nursing caries children: an in vivo study. Contemporary Clinical Dentistry. 2014; 5: 324–328.