Oral and Dental Medicine

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The Effect of Diode Laser 940 nm and 445 nm on the Rise in Temperature of a Pulp Simulating Material : In Vitro Study /
ElAasaly, Basant Bahaa ElDin Ibrahim,; Supervisor : Amira Farid El-Zoghaby, Ola Mohamed Ibrahim Fahmy.
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Effect of Er: Cr: YSGG laser on the remineralizing potentialof self-Assembly peptides in incipient carious lesions : (In vitro study).
(2022) Abdelhamid, Aghareed Alaa El-Din El-Sayed,; Supervisor : Adel Ezzat Khairy, Dina Wafik Elkassas.
The purpose of this in-vitro study was to compare the remineralizing capacity of self-assembling peptide applied after enamel surface pre-treatment with Er:Cr:YSGG laser, versus the use of laser and self-assembling peptide on their own for the treatment of incipient enamel carious lesion. A total of 32 enamel specimens from human molars were collected and decoronated 2mm below the CEJ. Crowns were embedded in self-cure acrylic resin mold facing upwards. Teeth surfaces were scaled and polished flat to facilitate the micro-hardness test. A 4*4 mm window of exposed enamel was prepared, and the rest was covered with acid-resistant nail varnish. White spot lesions were artificially induced on all enamel samples via immersing the samples individually in a demineralizing solution for 4 days that was daily renewed. After white lesion formation, all samples were rinsed under running water. Enamel samples were then divided into 4 main groups according to the remineralizing regimen; Group I (Artificial saliva) as negative control, Group II (Self-assembly peptide Curodont Repair), Group III (Er:Cr:YSGG laser: pulse duration of 60 microseconds, average power 4W energy, 60% water 40% air, repetition 50 Hz, energy density 15.9 J/cm2, tip in non-contact mode at a distance of 2 mm) and Group IV (Er:Cr:YSGG laser + Self-assembly peptide Curodont Repair) All enamel samples were pH cycled for 14 days, 2 hours in demineralizing solution and 22 hours in remineralizing solution and fresh solution were applied after 4 days. Surface microhardness test was carried out using Vickers testing machine with a 100 g load indenter held for 15 seconds; at baseline, after demineralization and after treatment with pH cycling. Three indentations were made for each reading and their average was taken to represent the specimen’s hardness value. The final results of the study showed that all three treatment modalities promoted remineralization of the demineralized enamel surface lesion. Similar outcomes for groups II and III were obtained, while group IV showed the highest statistical significance.
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Effect of glass ionomer surface hardness by using LED, calcium chloride and plasma Arc : (In-vitro Study) /
Soliman, Mirna Ashraf Soliman,
To measure and compare the effect of LED, Calcium chloride solution, Calcium chloride gel and Plasma Arc on the surface hardness of conventional Fuji IX GIC twice, at baseline and after pH cycling. A total of 50 encapsulated conventional Fuji IX GP FAST GIC were mixed to form disc-shaped specimens using a split-teflon mold. They were divided into 5 groups of 10 specimens each. Group 1 (control): specimens were left to set conventionally without any treatment. Group 2 (LED): the top surface of the specimens was irradiated for 40s by LED during setting. Groups 3 (CaCl2-Sol.): the top surface of the specimens was treated with CaCl2 solution for 2 minutes during setting. Group 4 (CaCl2- Gel): the top surface of specimens was treated with CaCl2 gel for 2 minutes during setting. Group 5 (Plasma Arc): the top surface of the specimens was irradiated with Plasma Arc curing device for 10s during setting. Next, baseline surface hardness was measured by using Vickers Micro-Hardness Tester. Finally, all groups were exposed to a pH cycling protocol using 5% acetic acid, pH=3, for 14 days. Finally, surface hardness was re-measured after pH cycling. The results showed significantly higher values for the surface hardness of Fuji IX GIC specimens treated by: LED, Calcium Chloride and Plasma Arc in comparison to the control untreated specimens. Plasma Arc showed the highest significant hardness values, compared to the other tested groups. However, LED, CaCl2 solution and CaCl2 gel showed comparable results. CaCl2 solution group showed significantly lower values compared to LED irradiated group. Finally, pH cycling had significant adverse effects on the overall hardness of all tested groups, showing a decrease in surface hardness except for the Plasma Arc irradiated group.
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Impact of Using Nano-Hydroxyapatite on Color Stability and Postoperative Hypersensitivity of Two Bleaching Techniques : Randomized controlled Clinical Trial /
Ahmed, Hebat-Allah Mostafa Mohamed,; Supervisor : Olfat Sayed Hassanein, Dina Wafik Elkassas, Ahmed Mohamed Hoseny Fayed
The search for a more esthetic smile has grown exponentially during the last few decades. Consequently, tooth color is currently believed to be one of the biggest today’s patients concerns.(1, 2) Tooth bleaching has been recognized as simple, effective and well-accepted method for solving the problem of teeth discoloration. There are three major approaches to bleaching of vital teeth. In office bleaching, which is clinician supervised, “night guard” bleaching which is administrated by the clinician for home use by the patient, and commercial bleaching products which are applied by the patient.(3) In comparison between the three techniques, in –office bleaching has shown many advantages over the other techniques. It included the professional control throughout the whole procedure, quick initial results, reduced treatment time in addition to avoiding any accidental material ingestion and discomfort in wearing bleaching trays. This made the in-office bleaching a pioneer in bleaching treatment.(4) In office whitening technique, which was named power bleaching by many authors,(5, 6, 7, 8) is achieved via the use of high concentrations of hydrogen peroxides. This technique can be classified according to the mode of activation of the bleaching gel into photo catalyzed and chemo catalyzed in-office bleaching systems.(2, 9) Conflicting results regarding the whitening outcomes were evident in literature between chemo and photo catalyzed bleaching techniques. Some studies found that the photo catalyzed bleaching systems gave better whitening results,(7, 9, 10, 11) while others found no difference between the whitening efficacy of both techniques.(4, 12) These conflicting results made the choice between both techniques confusing. Furthermore, concerns have been expressed about limitations to efficacy of both power bleaching techniques in term of color stability and post-bleaching hypersensitivity.(3) Regression of tooth whitening is an Introduction 2 evident drawback that may follow the in-office bleaching techniques.(16, 17) Studies related this to the surface alterations induced by the bleaching gel.(18, 19, 20, 21) In addition, post bleaching hypersensitivity is one of the most prevalent drawbacks of in-office bleaching technique.(6, 13, 14) Although being the most prevalent drawback, its etiology is not yet fully understood.(3, 15) Currently, in the dental market, many desensitizing agents are available. Recently, Nano technology has paved the way for introduction of materials at Nano scale level having the same chemical composition of either organic or inorganic analogue of the hard tooth structure making them biomimetic.(22, 23, 24) Consequently appeared the revolutionary role of using the Nano hydroxyapatite. Gopinath (23) and Jena,(13) reported the desensitizing effect of Nano hydroxyapatite paste, however their clinical trials were carried out on virgin dentin. Jin et al(22) and Pepla et al(25) reported the lightening effect of the Nano hydroxyapatite paste, however their studies were carried out on demineralized enamel specimens. They attributed this to its role to act as filler to fill and repair the small holes and pores in enamel. Based on these findings, it could be assumed that Nano particles of hydroxyapatite might block the pores induced by the bleaching gel, thus maintain color stability and also reducing the post bleaching hypersensitivity. However, the impact of using Nano hydroxyapatite paste on the color stability and post-bleaching hypersensitivity was not tackled enough in the literature. Thus this clinical trial was carried out to elaborate; first: the difference between photo and chemo catalyzed inoffice bleaching techniques on color stability and post bleaching hypersensitivity, second: to monitor the impact of Nano hydroxyapatite paste on color stability and post- bleaching hypersensitivity of the two tested in-office bleaching techniques.

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Browsing Oral and Dental Medicine by Subject "Operative Dentistry"