Erosive effect of industrialized fruit juices exposure in enamel and dentine substrates: An in vitro study.

BACKGROUND: Erosive tooth wear has been a highly prevalent and emerging phenomenon related to eating habits of the population. Aim: This study sought to investigate industrialized fruit juices exposure in enamel and dentine substrates in terms of erosive effect. MATERIAL AND METHODS: Human enamel and dentine specimens were randomized into 8 groups (n=8): Grape juice - Ades®, Grape juice - Del Valle Kapo®, Grape juice - Aurora®, Orange juice - Del Valle Kapo®, Orange juice - Ades®, Strawberry juice - Mais Vita®, Strawberry juice - Ades®, Citrus fruit juice - Tampico®. Specimens were submitted to an in vitro erosive challenge and to a microhardness test to evaluate the percentage of surface microhardness loss. The pH, titratable acidity, buffering capacity, degree of saturation and critical pH concerning hydroxyapatite and fluorapatite of the juices were measured as well as their composition of calcium, phosphate, fluoride, and total protein. Data were submitted to the analysis of variance and multivariate linear regression (α=0.05). RESULTS: All test agents were undersaturated concerning hydroxyapatite and fluorapatite. A significant interaction between the type of juice and substrate was found (α=0.000, ß=0.99). However, Orange juice - Del Valle Kapo®, Orange juice - Ades®, and Strawberry juice - Mais Vitta® demonstrated no difference between substrates. Grape juice - Ades® promoted less mineral than other juices in enamel and dentine. The calcium concentration in juices was a protective variable for microhardness loss in both substrates. CONCLUSIONS: The erosive effect of industrialized fruit juices affects enamel differently from dentine, and this effect differed between some, but not all, tested juices. Key words:Tooth erosion, dental enamel, dentine. beverages, food habits.

A novel combination of biallelic ALPL mutations associated with adult hypophosphatasia: A phenotype-genotype association and computational analysis study.

Hypophosphatasia (HPP) is an inherited metabolic disorder that causes defective skeletal and dental mineralization. HPP exhibits a markedly heterogeneous range of clinical manifestations caused by dysfunction of the tissue-nonspecific isozyme of alkaline phosphatase (TNSALP), resulting from loss-of-function mutations in the ALPL gene. HPP has been associated with predominantly missense mutations in ALPL, and a number of compound heterozygous genotypes have been identified. Here, we describe a case of a subject with adult-onset HPP caused by a novel combination of missense mutations p.Gly473Ser and p.Ala487Val, resulting in chronic musculoskeletal pain, myopathy, persistent fatigue, vomiting, and an uncommon dental phenotype of short-rooted permanent teeth. Pedigree and biochemical analysis indicated that severity of symptoms was correlated with levels of residual ALP activity, and co-segregated with the p.Gly473Ser missense mutation. Bioinformatic analysis to predict the structural and functional impact of each of the point mutations in the TNSALP molecule, and its potential contribution to the clinical symptoms, revealed that the affected Gly473 residue is localized in the homodimer interface and predicted to have a dominant negative effect. The affected Ala487 residue was predicted to bind to Tyr479, which is closely located the N-terminal α-helix of TNSALP monomer 2, suggesting that both changes may impair dimer stability and catalytic functions. In conclusion, these findings assist in defining genotype-phenotype associations for HPP, and further define specific sites within the TNSALP molecule potentially related to neuromuscular manifestations in adult HPP, allowing for a better understanding of HPP pathophysiology.