J.W.E. van Dijk

Biological calcium phosphates and their role in the physiology of bone and dental tissues I. Composition and solubility of calcium phosphates

SummaryVariations in the composition of bone and tooth mineral are consistent with the model that the constituents are a mixed microcrystalline apatite (AP)-octocalcium phosphate (OCP) like phase and an amorphous or submicrocrystalline calcium phosphate (ACP) like phase whereby these phases can occur in different proportions. An appropriate model for a description of the variable composition and the solubility behavior of the apatite phase is given by the formula

Caries Experience in the Deciduous Dentition as Predictor for Caries in the Permanent Dentition

\begin{array}{*{20}c} {\begin{array}{*{20}c} {Ca_{5 - x - y - u} Na_{\frac{2}{3} y} } \\ {\{ (PO_4 )_{3 - x - y } (CO)_{x + y} \} (H_2 O)_{y + z} OH_{1 - x - \frac{1}{3} y - 2u} } \\\end{array}} \\\end{array}

Effect of Time and Degree of Saturation of Buffer Solutions on Artificial Carious Lesion Formation in Human Tooth Enamel

in which the compositional parameters x, y, z, and u each account for one type of defect mechanism. Other point defects are formed as well by incorporation of minority amounts of ions such as Cl−, K+, and F−; a number of trace elements can substitute for Ca2+ ions under in vivo conditions. It is suggested that the incorporation of ions in or loss from the crystals in contact with aqueous solutions is reversible. Literature data are used to show the direction in which the solubility product of the apatite phase shifts by incorporation of the different physiologically relevant ions. A quantitative evaluation of the available literature data revealed that Na+ and CO3= incorporation is the main cause for shifts in the solubility product of biological apatites.

Solubility behaviour of whole human enamel.

In this study a mathematical model for the caries process is presented. It includes diffusion of ions, dissolution of mineral and complexation of ions. The conclusions from experiments with the model

Effect of the pH of buffer solutions on artificial carious lesion formation in human tooth enamel.

The present study aims at determining a reliable screening test for the prediction of caries. In order to identify children at risk of caries, individual classifications were recorded for 268 children at the age of 7 years, according to different screening criteria of the caries experience in the deciduous dentition and according to caries increment as validation criterion. In order to determine the best screening criterion, ratios of sensitivity, specificity and false-positive and false-negative ratios were computed and plotted in receiver operating characteristic curves. The best screening criterion at ≤ 4 dmft resulted in a sensitivity ratio of 0.69, specificity of 0.72 and diagnostic power of 0.78 for caries increment in the permanent dentition at the age of 7–11 years. The potential of the screening is elucidated with an example, showing that 48% of the expenses needed for a preventive treatment for all children could be saved by selecting children at risk with the aid of a screening test. The disadvantage of this decision making is that 19% of the children who develop caries would not benefit from the preventive treatment.

Relationships between Birefringence and Mineral Content in Artificial Caries Lesions of Enamel

In this study evidence is provided for the existence of a gradient in solubility and rate of dissolution of human tooth enamel. These gradients were obtained quantitatively by applying calcium and pho

The Surface Layer during Artificial Carious Lesion Formation

The chemical systems to produce carious lesions described in the literature can be divided into three types: (a) gel systems, (b) systems containing a substance which decreases the dissolution rate of

Influence of Fluoride and Carbonate on in vitro Remineralization of Bovine Enamel

The rate of dissolution of whole human enamel was studied by carrying out artificial caries experiments in buffers of known pH and known degree of undersaturation with respect to hydroxyapatite and by