title: Buffering of protons released by mineral formation during amelogenesis in mice.
abstract: Regulation of pH by ameloblasts during amelogenesis is critical for enamel mineralization. We examined the effects of reduced bicarbonate secretion and the presence or absence of amelogenins on ameloblast modulation and enamel mineralization. To that end, the composition of fluorotic and non-fluorotic enamel of several different mouse mutants, including enamel of cystic fibrosis transmembrane conductance regulator-deficient (Cftr null), anion exchanger-2-deficient (Ae2a,b null), and amelogenin-deficient (Amelx null) mice, was determined by quantitative X-ray microanalysis. Correlation analysis was carried out to compare the effects of changes in the levels of sulfated-matrix (S) and chlorine (Cl; for bicarbonate secretion) on mineralization and modulation. The chloride (Cl-) levels in forming enamel determined the ability of ameloblasts to modulate, remove matrix, and mineralize enamel. In general, the lower the Cl-content, the stronger the negative effects. In Amelx-null mice, modulation was essentially normal and the calcium content was reduced least. Retention of amelogenins in enamel of kallikrein-4-deficient (Klk4-null) mice resulted in decreased mineralization and reduced the length of the first acid modulation band without changing the total length of all acidic bands. These data suggest that buffering by bicarbonates is critical for modulation, matrix removal and enamel mineralization. Amelogenins also act as a buffer but are not critical for modulation.
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands. a.bronckers@acta.nl.|VU University Amsterdam, MOVE Research Institute, Amsterdam, the Netherlands. a.bronckers@acta.nl.
authors.forename: Antonius L J J
authors.initials: AL
authors.lastname: Bronckers
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Don M
authors.initials: DM
authors.lastname: Lyaruu
authors.affiliation: Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Rozita
authors.initials: R
authors.lastname: Jalali
authors.affiliation: Department of Oral Sciences, University of California in San Francisco, CA, USA.
authors.forename: Pamela K
authors.initials: PK
authors.lastname: DenBesten
mesh_terms: D000565:Ameloblasts; D000566:Amelogenesis / Q000502:physiology*; D053523:Amelogenin; D000818:Animals; D003743:Dental Enamel / Q000378:metabolism; D003746:Dental Enamel Proteins; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008903:Minerals; D011522:Protons
chemical_list: D053523:Amelogenin; D003746:Dental Enamel Proteins; D008903:Minerals; D011522:Protons
keywords: amelogenin; cystic fibrosis transmembrane conductance regulator; dental fluorosis; kallikrein 4; pH regulation