Objectives: This clinical study was conducted to evaluate the efficiency of nanohydroxyapatite (n-HAp) in reducing dentin hypersensitivity individually or combined with fluoride. Materials and methods: Forty hypersensitive teeth from 10 patients with hypersensitive symptoms were treated using hydroxyapatite nanoparticles (nHAp) gel at different concentrations/ sodium fluoride (NaF) containing according to four treatment groups: Group 1; 15% nHAp + 1% NaF, Group 2; 15% nHAp, Group 3; 25% nHAp+ 1% NaF, Group 4; 25% nHAp. The initial sensitivity levels were recorded using a verbal rating scale (VRS) and visual analogue scale (VAS) at the baseline visit. The responses were evaluated at 0, 1 day, 1, 2 and 4 weeks respectively for all groups. Results: There was a high statistical significant differences between pain scores before and after treatment for all treated groups. There was statistically significantly high difference between 25% nHAp and the other groups, as they need 4 applications for complete relief while 25% nHAp needs only 3 applications. Conclusion: Nanohydroxyapatite with 25% concentration was the most effective in alleviating the hypersensitivity symptoms.

The purpose of this study was to evaluate the effect of 0.05% sodium fluoride and 0.12% chlorhexidine mouthwashes on the micro-hardness of tooth enamel and cementum that was exposed to therapeutic doses of gamma radiation. Sixty extracted human teeth were divided into two groups, one was irradiated, the other was not irradiated. The two groups were further subdivided into three subgroups, which were each treated either with 0.05% sodium fluoride or with 0.12% chlorhexidine; the third subgroup served as a control. After demineralization-remineralization cycling, teeth from the irradiated groups showed a significantly lower micro-hardness when compared to those from the non-irradiated groups. Both in the irradiated and non-irradiated groups, teeth from the control subgroups showed a significantly lower micro-hardness, as compared to teeth treated with sodium fluoride and chlorhexidine. For non-irradiated enamel samples, those treated with chlorhexidine showed a significantly less micro-hardness compared to those treated with sodium fluoride. In contrast, irradiated enamel showed no significant difference in micro-hardness, whatever treatment (chlorhexidine or sodium fluoride) was applied. For cementum, treatment with chlorhexidine resulted in a significantly lower micro-hardness compared to sodium fluoride, both for the irradiated and non-irradiated groups. It is concluded that gamma irradiation with therapeutic doses typically used for head and neck carcinoma treatment has a direct effect in reducing micro-hardness of tooth enamel and cementum. Mouthwash protocols including, for example, application of 0.05% sodium fluoride or 0.12% chlorhexidine three times per day for 6 weeks, can protect enamel and cementum against the reduction in hardness and demineralization caused by gamma irradiation. Sodium fluoride offers more protection compared to chlorhexidine.

Purpose: to evaluate the biological response of the dog teeth to Platelets Rich plasma (PRP), Platelets Rich fibrin (PRF) and mineral trioxide aggregate (MTA) as pulp capping materials. Material and Methods: A total of 90 teeth of dogs were included. Class V cavities were prepared. Pulp exposure was performed in the middle of cavity floor. The teeth were divided into three groups of 30 teeth according to the material used; A1: PRP, A2: PRF and A3: MTA. Glass ionomer restoration was applied as restoration for the cavities. The tissue response to the materials was assessed at three different post-operative periods of 7, 30, 60 days. The animal was sacrificed. Histomorphometric analysis was performed. Result: the results showed high inflammatory cells count at 7 days for all treated groups; PRP treated teeth showed the highest at 7 days, while PRF showed the least. At 1 and 2 months postoperatively no significant difference was found between all the treated groups. For dentin bridge scores; there was no significant difference between all the materials at 7 days and 1 month. At 2 months; the MTA treated teeth recorded the greatest dentin bridge score as compared to all treated teeth.As for integrity of odontoblast score; results showed no significant difference between different materials at 7 days and 1 month. The MTA treated teeth showed the highest score as compared to PRP and PRF at 2 months. Conclusion: Among the three different materials, PRP and PRF appeared to be promising pulp capping agents.

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Purpose: This study aimed to evaluate and compare the remineralizing and antimicrobial effect of chitosan-based agent and Flavonoid. Materials and methods: This study was carried out in two phases; remineralization phase and antimicrobial phase. Ninety (90) bovine mandibular incisors were used in the study with forty-five (45) teeth in each phase. Teeth were prepared and randomized into three groups according to treatment material (n=15 samples) as follows; group I; control group (being immersed in artificial saliva), group II; treated with flavonoid and finally group III; treated with chitosanbased agent. Each agent was applied for 10 minutes six times/day. In phase (1) remineralizing effect was measured through recording radiodenisty (by using digital radiography) at baseline, after creation of lesion and after treatment. In phase (2) antimicrobial effect was measured (by using colony forming unit test and lactic acid production test) at baseline and after treatment. Data were obtained and the differences between groups were estimated by ANOVA test followed by Tukey's post hoc test. Results: Statistical analysis by ANOVA test revealed that there was high statistically significant difference between the study groups. Dentin blocks treated by chitosan-based agent showed greater remineralizing effect than flavonoid. Dentin blocks with 1,4 and 7 days biofilms treated with Flavonoids showed greater inhibition of Lactic acid production and Colony forming unit. Conclusion:-Chitosan-based agent can be used as remineralizing agent while flavonoid can be used as antimicrobial agent against S.mutans by inhibiting colony forming unit and lactic acid production..