Fouad S Salama.
Microhardness and mineral contents of sound and carious human primary teeth.
J Pak Dent Assoc Jan ;13(2):72-5.

OBJECTIVE: The aim of this in vitro study was to determine and compare the surface microhardness as well as calcium (Ca) and phosphorus (P) mineral contents of sound and carious human enamel and dentin of primary teeth. MATERIALS AND METHOD: Sixteen specimens (8 sound and 8 carious) of primary molars were prepared for determination of microhardness at three points, which include the center of enamel, the dentin below the amelo-dentinal junction (superficial dentin) and deep dentin (above the pulp) using a hardness tester. The specimens were then prepared for Energy Dispersive X-ray microanalysis (EDX) by which enamel and dentin calcium (Ca) and phosphorus (P) contents were determined near all sites in which measurements of microhardness were performed. Statistical analysis was conducted using one-way nonparametric Analysis of Variance followed by Tukey type nonparametric post hoc test. RESULTS: The highest mean Vickers hardness numbers (VHN) was evident for sound enamel 274.247 + 10.927 (X ± SD). There was significant difference between Ca and P of sound enamel and all other groups (P<0.0001). CONCLUSION: It was concluded that the enamel and superficial dentin on the carious primary teeth was significantly softer than sound enamel and superficial dentin. The overall decrease of microhardness of enamel as well as superficial and deep dentin of primary teeth by caries was 24%, 22% and 15%, respectively. The Ca:P ratio of sound enamel had a higher content of Ca than superficial and deep dentin.

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