الفهرس 
Introduction and Review of LiteratureOnly 14 pages are availabe for public view
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Abstract
DH is a significant global clinical oral health problem in the adult population. DH is defined as “short, sharp pain arising from exposed dentin in response to stimuli typically thermal, evaporative, tactile, osmotic or chemical, which cannot be ascribed to any other dental defect or pathology”. It can affect people of any age, although those aged 20–50 years are more likely to be affected. Females are slightly more likely to develop dentin hypersensitivity compared to males. The condition is most commonly associated with the maxillary and mandibular canine and bicuspid teeth on the facial aspect, especially in areas of periodontal attachment loss.
In order to tackle this problem, desensitizing agents were used. from which, fluoride varnish is one of the most commonly used desensitizing agents. Treatment of the exposed root surfaces with sodium fluoride toothpaste and concentrated fluoride solutions is very efficient in managing DH, since its mode of action depends on precipitation of calcium fluoride crystals on dentin surface and induction of a high mineral content which creates a calcific barrier blocking the tubular openings on the dentin surface.
In terms of cost-effectiveness, the health industry has always used natural products as an alternative, to the conventional allopathic formulations available for the treatment of DH. For instance, propolis; a natural antibiotic which is a resinous yellow brown to dark brown substance that honey bees collect from tree buds was recommended. The main chemical classes present in propolis are flavonoids, phenolics and other various aromatic compounds. Flavonoids are well known plant compounds that have antibacterial, antifungal, antiviral, antioxidant and anti-inflammatory properties. Propolis works by deposition of the resinous material on dentin surface and interlocking with tubule orifices.
Therefore, this study was carried out to evaluate and compare the effect of propolis and sodium fluoride on exposed dentinal tubules viewed by scanning electron microscope. This was accomplished by:
1. Examination of transverse and longitudinal sections of dentinal tubules.
2. Histomorphometric study using image analyzer to examine:
-Number of open dentinal tubules.
-Surface area percentage of dentinal tubules.
Twenty-one caries-free human premolars were collected. Dentin discs were prepared and treated with acid etch to remove smear layer and expose dentinal tubules. Samples were randomly divided into three groups, seven dentin discs each, according to the treatment solution used as follows:
group I - Control group: specimens treated with acid etch with no additional treatment.
group II - Fluoride group: specimens treated with sodium fluoride containing agent. (bifluorid®).
group III.- Propolis group: specimens treated with ethanolic extract of propolis (EEP).All samples were examined under SEM to evaluate the effect of tested agents on occlusion of dentinal tubules and were analyzed using ImageJ Digital Analyzer. The statistical analysis was performed using the arithmetic mean, standard deviation (S.D.), unpaired t test and analysis of variance (ANOVA).
The SEM examination of group II and group III transverse sections revealed that predominantly higher number of dentinal tubules showed complete and partial tubular occlusion in comparison to group I. While upon examination of longitudinal sections, group II showed a layer of crystals covering the tubules and group III showed a homogenous layer of propolis covering the tubules with interlocking of the material into the tubules orifices. The statistical analysis of our results were observed regarding both parameters measured: the number of dentinal tubules and the area percentage of open tubules occupied in the total area. Results presented that there was highly significant difference between group I and group II and between group I and group III. But there was no significant difference between group II and group III. Both group II and group III showed significant decrease in number of opened tubules and mean area percentage of opened tubules.