الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 97 |  |  |
| | | from | 97 | | |
Abstract
Dental caries remains the most common preventable chronic oral disease. The protective and tooth resisting modalities against dental caries include fluoride ions incorporation into the developing hydroxyappatite crystals and the incipient caries. Fluoride incorporation into the crystalline lattice of the dental hard tissues makes it less soluble in acidic environment. This can be achieved through daily tooth brushing with fluoride tooth pastes. The fluoride bioavailability has a very important effect in caries prevention, it depends on the solubility of fluoride containing compounds, which leads to the adhesion of the fluoride compound to the tooth surface. Fluoride reactivity is characterized by fluoride uptake, surface micro-hardness and lesion mineral content. Accordingly, pH cycling models were developed to evaluate carious lesions and mineral changes in dental hard tissues.
The objective of this study is to evaluate enamel surface microhardness and fluoride uptake in primary teeth after subjecting them to pH cycling and their treatment by different fluoride dentifrices in vitro.
The materials used in this study were NaMFP dentifrice (F 500 ppm), and NaF tooth paste (F 500 ppm).
The sample consisted of 75 freshly extracted caries-free primary teeth, which were divided into two groups:
- group I: it was evaluated for microhardness and consisted of 45 blocks that were divided, according to the materials used, into 3 subgroups:
• Subgroup (Ia): treated with NaMFP dentifrice (F 500 ppm).
• Subgroup (Ib): treated with NaF tooth paste (F 500 ppm).
• Subgroup (Ic): control (remained in distilled water).
- group II: it was evaluated for fluoride uptake and consisted of 30 teeth, each tooth was divided in to two halves, where one acted as control and the other as experiment. Experimental halves were treated with one of the following materials and were divided into:
• Subgroup (IIa): treated with NaMFP dentifrice (F 500 ppm).
• Subgroup (IIb): treated with NaF dentifrice (F 500 ppm).
Laboratory data was collected, tabulated and analyzed using suitable statistical tests to achieve the aim of the study.
There was microhardness recovery for the 3 subgroups. There was no significant difference between Ia: NaMFP subgroup and Ib: NaF subgroup, while subgroup Ic: control subgroup was significantly less than both subgroups. Ib: NaF subgroup, scored the highest (Mean±SD) value followed by Ia: NaMFP subgroup then Ic: control subgroup.
Fluoride uptake in IIb: NaF subgroup showed a significantly higher (mean±SD) value than IIa: NaMFP subgroup.