Histomorphometric and Microchemical Characterization of Maturing Dental Enamel in Rats Fed a Boron-Deficient Diet

Abstract

Few reports are available in the literature on enamel formation under nutritional deficiencies. Thus, we performed a study to determine the effects of boron (B) deficiency on the maturing dental enamel, employing the rat continuously erupting incisor as the experimental model. Male Wistar rats, 21 days old, were used throughout. They were divided into two groups, each containing ten animals: +B (adequate; 3-mg B/kg diet) and -B (boron deficient; 0.07-mg B/kg diet). The animals were maintained on their respective diets for 14 days and then euthanized. The mandibles were resected, fixed, and processed for embedding in paraffin and/or methyl methacrylate. Oriented histological sections of the continuously erupting incisor were obtained at the level of the mesial root of the first molar, allowing access to the maturation zone of the developing enamel. Dietary treatment did not affect food intake and body weight. Histomorphometric evaluation using undecalcified sections showed a reduction in enamel thickness (hypoplasia), whereas microchemical characterization by energy-dispersive X-ray spectrometry did not reveal alterations in enamel mineralization.

Does age estimated from teeth forming in different early life periods show differential discrepancy with known age?

“…For instance, animal and in vitro human studies have demonstrated the role that calcium has in ameloblast differentiation, organization, and activity, with enamel forming under hypocalcemic conditions being reduced and improperly mineralized (Bonucci, Lozupone, Silvestrini, Favia, & Mocetti, 1994; Chen, Zhang, Mendoza, & Den Besten, 2009; Nanci et al, 2000). Similar results were also found in animal studies on vitamin C (Shrestha, More, Keshwar, Shrestha, & Raut, 2019), boron (Haro Durand, Mesones, Nielsen, & Gorustovich, 2010), and vitamin D (Limeback et al, 1992), highlighting the various potential consequences a poor nutritional environment can have on tooth formation. Based on these findings, it is possible that the children within the Certosa sample experienced higher levels of malnourishment relative to those within the Lisbon and Spitalfields samples, as indicated by their delayed tooth growth.…”

Epigenetics in developmental defects of enamel: A scoping review

“…However, the current researches are mainly based on in vitro studies or animal models, lacking of direct evidence. A study in rats shows boron deficiency caused a reduction in enamel thickness while the mineralization was not affected (Haro et al, 2010). Perinatal and postnatal factors significantly connected with the etiology of MIH (Garot et al, 2022).…”

Growing Evidence for Human Health Benefits of Boron

“…In addition to adversely affecting bone, boron deprivation reduced enamel thickness (hypoplasia) in maturing dental enamel of rats. 35 The changes in bone structure and formation induced by boron deprivation apparently affect bone strength and could increase the risk of osteoporosis. Boron deprivation decreased bone strength variables determined by a 3-point bending test of femurs from pigs 36,37 and rats.…”

“…In addition to adversely affecting bone, boron deprivation reduced enamel thickness (hypoplasia) in maturing dental enamel of rats. 35…”