PubMed Health⌕ Search

Biomedical subjects

J Yvon

Publications and source records attributed to J Yvon.

4 recordsLinked to original sources
PubMed1995

Dental abnormalities and early diagnosis of hyperphosphatasemia.

Dental hard tissue abnormalities have never been described as part of the symptoms associated with hyperphosphatasemia. Fourteen teeth obtained from a young man, who had a mild form of hyperphosphatasemia, were analyzed using scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD), and infrared (IR) spectroscopy. SEM revealed a thin enamel, presenting a prismatic structure with many pits, and atypical cementum and dentin showing numerous resorption areas. The X-ray diffractograms revealed poorly crystalline hydroxyapatite associated with alpha-tricalcium phosphate and magnesium hydroxide phases. SIMS data showed high Ca concentrations: 40.5 weight % ¿wt%; standard deviation (SD = 0.13) and 42.5 wt% (SD = 1.03) in enamel and dentin respectively, and high Ca/P weight ratios: 2.28 in the enamel, 2.65 in the dentin. The lack of crystallinity may be linked to the high content of proteins and magnesium adsorbed onto apatite. This study demonstrates the need for thorough radiographical and biological investigations for skeletal abnormalities, even in the absence of systemic symptoms, when generalized dental abnormalities of both enamel and dentin are observed.

Adult↗
PubMed1994

Shear bond strength of a light-cured resin composite vs. dentin characteristics.

OBJECTIVES: The aim of this work was to determine if any significant correlation can be found between dentin characteristics and the shear bond strength of a bonded resin composite. METHODS: The number of tubules, the diameter of tubules, the real dentin surface (RDS), the Vickers hardness (VHN), and the Ca and P concentrations ([Ca] and [P]) were measured. Two commercial bonding systems, the All-Bond 2 (Bisco) and Scotchbond 2 (3M Dental Products), were tested on 70 extracted human molars purposely abraded and polished. Experimental results were statistically analyzed. RESULTS: The average bond strength ranged from 9.1 +/- 5.3 MPa (All-Bond 2) to 3.2 +/- 1.9 MPa (Scotchbond 2). Only the Bisco adhesive gave rise to cohesive dentin fractures. The Vickers hardness depended on both the real dentin surface and the calcium concentration according to the empirical law: VHN = 0.753 RDS + 0.320 [Ca] - 16.330. The shear bond strength does not depend on the measured dentin characteristics. SIGNIFICANCE: Under these testing conditions, the nature of the surface composite determined the adhesion; the properties of the dentin substrate were of minor importance.

Adhesiveness↗