Oral and Dental Medicine

Permanent URI for this communityhttps://iorep.miuegypt.edu.eg/handle/20.500.13071/5

Browse

Now showing 1 - 20 of 124

Restricted
Accuracy of conventional and digital impressions at different span lengths of missing teeth : (In-Vitro study).
(2022) El-Sheikh, Nada Ali Mohamed,; Supervised : Rana Sherif, Mostafa Hussein .
Impression taking is a crucial step in prosthodontics, as the quality of the final prosthesis and its long term survival depends on the accuracy of this process. Conventional impressions are the most common in the clinical practice; conventional workflows and CAD/CAM technologies can be combined through indirect digitization. However, new digital techniques allow the full digitization of the workflow, by the use of IOSs. The main feature to be evaluated in an intraoral scanner is accuracy. According to ISO 12836, the accuracy of an impression technique is defined in terms of trueness and precision. Trueness is defined as the difference in measurement between the reference model and the scan model and precision is the difference in measurement between digital models created using the same impression technique. This in-vitro study was designed to evaluate the accuracy of three different impression techniques at three different span length bridges. For full arch prostheses and FPDs with more than 5-units, digital impressions do not seem as accurate as conventional impressions. Therefore, the aim of this study was to assess the accuracy in terms of trueness and precision of conventional and digital scanning (direct and indirect) techniques on different span length bridges. The bridge preparations were done on acrylic typodont models (Nissin, Kyoto, Japan) with the aid of a dental surveyor. Three different impression techniques were used, a conventional PVS impression material (Elite HD+ putty soft and light body consistencies), an intraoral scanner (CEREC Primescan) and an extraoral scanner (Medit Identica t300). The three groups (3,4 and 6-unit bridges) were divided into 3 subgroups according to the impression technique received (PVS, Primescan and Medit t300). For the trueness measurement, the three different bridge types were scanned using a desktop scanner (inEos X5) which was used as the reference scanner to obtain the reference datasets (REF STL files). The different impression techniques were used to record five different impressions (n=5) for each bridge span type and with the help of a reverse engineering 3D analysis software (Geomagic Control X), the digitized measurement models were superimposed on the reference to calculate the amount of deviation or RMS value of error. For the precision measurement, the calculations were done within each subgroup. Each scan was considered as the reference superimposing the remaining 4 scans in pairs to calculate the amount of deviation or RMS value of error. Color difference maps and reports were generated for all of the test groups. Data was recorded, tabulated and analyzed. Statistical work was done using the two-way ANOVA test. Results Regarding the different span length bridges, the best trueness and precision values were recorded for the 3-unit posterior followed in descending order by the 4-unit posterior and 6-unit anterior bridges for all three impression techniques. Regarding the impression technique, the best trueness values were recorded by Primescan followed by PVS and Medit t300. The best precision values were recorded by Medit t300 followed by Primescan and then PVS, all of which showed statistically significant difference.
Restricted
Effect of Nano forms of propolis and antibiotic pastes as canal medicaments on radicular dentin micro-hardness and chemical structure : (In vitro study).
(2022) Abdel-Elnasser, Aya Gamal,; Supervisor : Abeer Abdel Hakim El-Gendy, Amr Bayoumi.
The aim of this study was to evaluate the effect of Propolis and Antibiotic Pastes (Double and Triple) in both Micro and Nano-forms on radicular dentin micro-hardness and chemical structure. Forty-two extracted human single rooted mandibular premolars were collected with mature apices and one root canal. Those teeth were deidentified and checked radiographically. The forty-two teeth were classified into three different experimental groups equally (14 each) according to the type of testing materials; group A (Propolis-PRP), group B (Double antibiotic paste- DAP) and group C (Triple antibiotic paste-TAP). Each group will be subdivided into two subgroups (7 each) according to the particle size used to prepare the medicament either Micro or Nano-sized. Subgroup A1 (Micro-PRP), subgroup A2 (Nano-PRP), subgroup B1 (Micro-DAP), subgroup B2 (Nano-DAP), subgroup C1 (Micro- TAP) and subgroup C2 (Nano-TAP). Teeth were decoronated to a standard 16 mm, an apical patency was checked using K-file #10 then 1mm was subtracted in order to establish an accurate working length. Mechanical preparation was done using Mpro three files rotary system with 3ml of 2.6% sodium hypochlorite irrigation with manual dynamic agitation subsequent to each filing step. Canals were rinsed with saline as a final flush and dried with paper point. The prepared samples were subjected to longitudinal sectioning resulting in buccal and lingual halves by an isomet. All buccal halves considered as the experimental half while lingual halves considered as the coronal half. Each half was mounted in acrylic resin for easy material application and machine testing. Each lumen was encircled by pink wax to preserve medicament in place. Each experimental group received precisely 1 ml of the assigned medicament for each subgroup. Then samples left untouched and stored for two weeks in 37C° and 100% humidity in incubator. After 14 days, 2.5% NaOCL irrigation using ultrasonic file # 15 for one minute with power 9 was used in order to remove and wash away the applied medicaments. Following that, the lumens were flushed thoroughly with 5ml distilled water. Samples were subjected to the Vickers micro-hardness and an Energy Dispersive Xray- Scanning Electron Microscope (EDX-SEM) test to check both the control and experimental group’s micro-hardness and chemical structure. Moreover, both control and experimental samples were fixed in the Vickers machine in a manner allowing the sample’s half to face upward toward the machine indenter. Three indentations have been done at coronal, middle and apical levels. The indenter was placed smoothly at 1 μm form the lumen, creating indentations at the edge towards the dentin outer border using 50 g load for 10 seconds. The indenters were measured using an optical microscope connected to a digital camera with image analysis software. After the load is removed, the indentation is focused with the magnifying eye piece and the two impression diagonals were measured, usually to the nearest 0.1- μm with a micrometer, and averaged. The final hardness values were obtained as the mean of each three indentation readings. Furthermore, the same specimens both control and experimental were subjected to a specific type of x-ray that would be detected by an EDX detector at the root parts that are devoid of previous indentations. The detector was placed in a very close angle to the sample’s half, detecting the generated photons of the x-ray; to predict the integrity of this sample. Afterwards; the halves were introduced into the scanning electron microscope that is already attached to EDX. Evaluation, analyzation and detection of any morphological and structural changes within the samples were made, at accelerating voltage 30 K.V magnification14x up to 1000000 and resolution for Gun.1nm. Upon comparing the outcomes, the results showed that the material and root canal level had a statistically significant effect on the median percentage change on root dentin micro-hardness. DAP as an intracanal medicament had the greatest effect regarding percentage reduction on dentin micro-hardness, followed by Nano-TAP. Also, with respect to root levels, there was no significant difference found at the coronal root level. However, DAP and Propolis had the highest statistically significant median percentage decrease in micro-hardness at the middle root level, while Nano-TAP had the highest statistically significant median % reduction in micro-hardness at apical root levels. Upon comparing chemical structure outcomes, the results showed that there was a statistically significant mean calcium weight % difference found between canal medicaments at different root levels. Control group had the highest statistically significant mean calcium weight %, whereas Propolis had the lowest statistically significant mean calcium weight % among the groups at different root levels. Additionally, the coronal root level had the highest statistically significant mean calcium weight % among middle and apical root levels. In addition, the results showed that there was a statistically significant mean phosphorus weight % difference found between canal medicaments at different root levels. Propolis group had the highest statistically significant mean phosphorus weight %, whereas control had the lowest statistically significant mean phosphorus weight % among the groups at different root levels. furthermore, no statistically significant difference was found between the middle and apical root levels; both had the highest statistically significant mean phosphorus weight % than coronal root level. Besides, the results showed that there was a statistically significant mean Ca:P ratio difference found between canal medicaments at different root levels. The control group had the highest statistically significant mean Ca:P ratio, whereas the Propolis group had the lowest statistically significant mean Ca:P ratio among the groups at different root levels. Also, the coronal root level had the highest statistically significant mean Ca:P ratio among middle and apical root levels. Finally, there was no statistically significant correlation between Ca, P weight %, Ca:P ratio and percentage decrease in microhardness.
Restricted
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.
Restricted
Push-out and Adaptability of a Novel Calcium Silicate Based Root Canal Sealer in Comparison with MTA Based Sealer : (in vitro study) /
Mostafa, Osama Magdy Monir,; Supervisor : Nihal Ezzat Sabet, Amira Galal Ismail.
Successful endodontic treatment depends on the complete chemomechanical debridement, and 3D obturation of the canal space to prevent the bacterial ingress from the oral environment and its outspread to the periradicular tissues. The most crucial objective of this treatment is to eliminate the microbial entity and any possible future re-infection. Achieving this is by providing proper seal to diminish any chance of proliferation of microorganisms and occurrence of any pathology. Sealer combined with a solid obturating material acts in harmony to create this hermetic seal. Along time, endodontics has been going through enormous evolution where plenty of materials have been innovated. This reflects in the production of various types of root canal sealers; based on their composition, root canal sealers can be classified according to their composition as zinc oxide based sealers, sealers containing calcium hydroxide, glass ionomer based sealers, resin sealers, silicone based sealers, urethane methacrylate sealers, solvent based sealers, epoxy resin, methacrylate resin based sealers, and recently calcium silicate based sealers. The properties of ideal root canal sealers include being tacky when mixed to create good adhesion between it and the canal wall when set, to provide a tight seal. It should also be radiopaque so it can be radio-graphically visible. Moreover, its powder particles ought to be very fine to easily mix with the liquid, it must not shrink upon setting, nor must it stain the tooth structure, and it should not encourage bacterial growth. In addition to that, it should set slowly, be biocompatible, insoluble in tissue fluids, that is, and it should dissolve in a 1 Introduction common solvent to be able to remove it when needed. Another important property is that it should not provoke an immune response in periradicular tissues, and it should not be carcinogenic. The quality of the seal obtained with gutta-percha when used with conventional zinc oxide eugenol sealers was not very promising; it does not adhere to dentin, unable to control micro leakage, and the solubility of sealer makes prognosis very poor. However, new materials have been developed as alternatives that show better seal and mechanically strengthen compromised roots by achieving monoblocks, which has been claimed to decrease the ingress of bacterial pathways and reinforce the root to some extent. Among them are silicon-based sealers which are biocompatible, have low water sorption, and capable of forming monoblock, which reinforces the root canal. Epoxy resin–based sealers also have good of adhesion to the dentinal wall and with lower water solubility, and the breakthrough of mineral trioxide aggregate (MTA) -based sealers which have the tendency toward mineralization, along with all the viable properties of standard sealers. However, resin-based and silicon-based materials have shown to be also soluble, which may endanger a proper seal. Recently, bioceramics have been involved in the production of root canal sealers allowing, for the first time, to benefit from all its advantages and not limiting its use to merely roots repairs and apical retrofills. This is achieved due to the recent innovations in nanotechnology; the particle size of bioceramic sealer is so fine (less than two microns), it can be carried within a 0.012 capillary tip. This material has been introduced and considered as non-toxic calcium silicate cement that can be used as a root canal sealer in endodontics. Introduction The popularity of the use of bioceramics in the dental field, specifically endodontics is that bioceramics are very biocompatible, are not toxic, with no shrinkage –on the contrary it expands- upon setting, and are chemically stable within the biological environment. Also bioceramics will induce minimal, if any inflammatory response when overfilling occurs during obturation or in a root repair. Moreover, the material is able to form hydroxyapatite upon setting, and provide a strong bond between dentin and the filling material. The hydrophilic nature of the materials improves its adaptation to the canal wall. In essence, it is a bonded restoration, where the bond results from a hydration reaction that occur during the setting of this material; the calcium silicates in the powder hydrate to produce a calcium silicate hydrate gel and calcium hydroxide. The calcium hydroxide reacts with the phosphate ions to precipitate hydroxyapatite and water. The water continues to react with the calcium silicates to precipitate additional gel-like calcium silicate hydrate. The water supplied through this reaction is an important factor in controlling the hydration rate and the setting time. The mentioned reaction creates a bond between the sealer and the tooth structure, and forms adaption of this sealer on the dentin wall. Hence, these properties evoked the need to evaluate these sealers in this study.
Restricted
The effect of nano-silica coating on micro-shear bond strength of CAD/CAM PEEK to resin cement : (An in-vitro study).
Tawfik, Nourhan Hussein,; Supervisor : Hanaa Zaghloul, Tamer Elhamy Shokry.
Restricted
Effect of Diode Laser Irradiation of Bonding Agents Before Curing Versus Standard Bonding Protocol on the Shear Bond Strength Between Resin Cement and Dentin /
El-Hakim, Nada Maged Mohammed Mahmoud,; Supervisor : Ashraf Hassan Mokhtar, Tamer A. Hamza.
It has been more than half a decade since Buonocore and later Nakabayashi developed the concepts behind the most popular branch in restorative dentistry, dental adhesion. Owing to its ability to create intimate contact between the tooth and the restoration, adhesion theoretically eliminates marginal gaps, reduces micro-leakage, and prevents secondary caries. With the spread of the adhesive concept, came the development of resin cements, enabling bonding of indirect tooth-colored restorations through micro-mechanical interlocking instead of the conventional luting method employed by acid-based cements. Adhesive bonding, through appropriate surface treatment protocols, not only provides superior bond quality, but also increases the flexural properties of ceramic restorations. Flexural properties such as modulus of elasticity and strength prevent de-bonding of cemented restorations during function. However, due to the nature of adhesive bonding, it has been proven that the quality of adhesion is proportional to the performance of the bonding agent. Unfortunately, the performance of contemporary bonding agents is still flawed when it comes to dentin. Unlike enamel, which has about 96%wt inorganic material, dentin has a more complex heterogeneous structure, composed of about 70%wt inorganic material and up to 30%wt organic content and water. The dentinal structure is further complicated by its structural variability according to location, as it changes not only with differences in depth, but also from region to region within the same tooth. Moreover, the dentinal composition and structure constantly changes throughout life according to local factors such as age, trauma, and caries. This complex structure renders it challenging to achieve a reliable bond to dentin, and due to its hydrophilic nature, nano-leakage occurs at some point within the hybrid layer, resulting in eventual bond deterioration and failure. According to the recent literature, self-etch adhesive systems (6th, 7th, and 8th generation adhesives), also called simplified bonding systems, seems to outperform the etch and rinse adhesive systems in dentinal bonding. However, numerous studies still reported water-related bond deterioration after aging. The presence of HEMA, water, and ethanol, as well as the differences in molecular weights between acidic and cross-linking monomers have been blamed for the breakdown of adhesive interfaces created by simplified bonding systems. In light of these problems, improvements in bond formulations are constantly being attempted through diverse laboratory studies and clinical trials. But till now, manufacturers have yet to produce an adhesive system or technique that prevents dentin bond deterioration by time. Dental lasers have recently been gaining popularity, and their use have been incorporated into multiple restorative procedures, including dental adhesion. SE Gonçalves et al (1999) suggested an adhesive protocol in which a soft tissue laser irradiated on an uncured adhesive before polymerization resulted in a statistically significant increase in shear bond strength to dentin. The use of laser energy on the bonding agent before its curing has since been evaluated in further studies and has been further hypothesized to increase bond penetration, help evaporate the solvent, increase its degree of conversion (DC), and increase the modulus of elasticity of the hybrid layer. Some authors, however, obtained negative results, finding the laser to have no effect whatsoever on the bond strength. Others found an increase in immediate bond strength that dropped dramatically after aging. Nevertheless, achieving sustainable high dentin bond strengths is the ultimate goal of adhesive dentistry. The idea of incorporating laser energy to reach this goal is interesting as it is debatable. Therefore, in an attempt to further asses the validity of laser use in dentinal bonding, the aim of this study is to evaluate the effect of a soft tissue laser irradiated on uncured bonding agents on the dentin bond strength.
Restricted
Effect of Er, Cr : YSGG Laser Versus Acid Etching Surface Treatment on the Surface Roughness and Optical Properties of Two Pressable Lithium Disilicate Ceramics with Different Thicknesses : In-Vitro Study /
Morsi, Mohamed Tarek Anwar,; Supervisor : Ihab Mosleh Mostafa, Hanaa Hassan Zaghloul.
The increased demand for high esthetics initiated the development of tooth colored restorative materials having superior esthetic and mechanical properties to withstand the occlusal forces. Dental ceramic restorations provide high esthetics that mimic the dental appearance of natural dentition producing satisfactory results to the patients and clinicians. Dental ceramics have variable compositions with different crystalline content such as feldspathic glass porcelain, zirconia, lithium disilicate, fluroapatite or leucite-reinforced ceramics. Glass ceramics consist of glassy matrix with imbedded crystalline structures. As the glassy matrix increases, the ceramics become more translucent. The crystalline content provides strength on the expense of its esthetic appearance. IPS e.max Press (first introduced into the market in 2005) consists of lithium disilicate crystalline structures (70% by volume) embedded into a glassy matrix7,8. The crystals have plate-like shape that are randomly distributed in the glassy matrix. The random distribution and the needle-like structure of the crystals would deflect cracks and prevent their propagation. GC InitialTM LiSi Press is a newly introduced lithium disilicate pressable ceramic, which is empowered by HDM technology (high density micronization) to provide improved physical properties (unsurpassed flexural strength of more than 450 MPa) while obtaining superior esthetics. With the advent of adhesive dentistry, ceramic veneers can be produced with high optical and mechanical properties in a minimum thickness up to 0.3 mm13–16. Aside from the layering fabrication technique, ceramic veneers can be constructed from ingots or blocks by heat pressing technique and computer assisted design/ computer assisted manufacturing (CAD/CAM) technique. The ceramic’s thickness has a noticeable effect on the optical properties of the ceramic restoration. Increased thickness affects color and translucency, making the ceramic darker more reddish/yellowish and increases the ceramic’s opacity. The bonding between the restoration and the dental structure is enhanced by the surface treatment of the ceramic surface. However, the modification of the internal surface of the ceramic by creating microporosities that would increase the surface area for bonding. The different surface treatments of ceramics affect the surface roughness which influences the optical properties of the ceramics. The roughness on the ceramic’s surface makes the light that goes through the ceramic pass with the different incidence and direction. Using Hydrofluoric acid etchant as a surface treatment is considered a standard classic method. Hydrofluoric acid removes the glassy matrix of ceramic material. Once the glassy matrix has been removed, the crystalline content is exposed creating micro-roughness on the surface of the ceramic. However, Hydrofluoric acid etchant as a surface treatment is considered hazardous to the dentist and the patient31. Er,Cr:YSGG Laser irradiation is a new technology that has been introduced lately to different fields of dentistry. Er,Cr:YSGG laser can make surface roughness on the glass ceramics as a surface treatment prior to bonding similar to that made by hydrofluoric acid etching. Reviewing the dental literature, there is a considerable debate regarding the effect of Er,Cr:YSGG Laser as a surface treatment protocol for producing surface roughness on the ceramic’s surface and its effect on the optical properties of the ceramic. In view of the unreported health hazards of laser irradiation in dentistry, it is worth to assess its effect as a surface treatment protocol on the surface roughness, color and translucency parameters of two pressable lithium disilicate ceramic materials with different thicknesses before and after aging.
Restricted
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.
Restricted
Impact of conservative access, truss access and remaining tooth structure on fracture resistance of maxillary first premolars : (In vitro comparative study) /
Shafik, Marian Safwat,; Supervisor : Abeer Hashem Mahran, Mohamed Alaa Fakhr. Includes Arabic Summary.
Tooth fracture is one of the undesirable phenomena of endodontically treated teeth and usually leads to extraction which is a major problem especially for teeth in the aesthetic zone. Endodontically treated teeth are generally weaker than sound teeth as a result of loss of sound tooth structure due to caries, access cavity and root canal instrumentation. Aim of the study: The aim of this study was to evaluate and compare the influence of different access cavity designs :(Conservative access cavity (CEC), Truss access cavity (TREC) and traditional access cavity (TEC)) and the remaining tooth structure on the fracture resistance of endodontically treated teeth. Methodology: 42 mature double rooted maxillary first premolars were randomly divided into a control group and three equal test groups according to the access cavity design prepared: CEC, TREC and TEC which were further subdivided according to the number of remaining walls either three or two remaining walls. CBCT was used to locate the root canal orifices for the preparation of the conservative access cavity designs. 24 sound upper first premolars were imaged with CBCT which were assigned to CEC and TREC. After CBCT scanning different access cavity designs were prepared, while teeth in the control group remained intact and were only evaluated for the fracture strength. After access cavity prepartion, a standeridized MO and MOD cavities were made using flat ended diamond fissure bur with rounded angles for the occlusal cavity. Then all teeth (control and test groups) were embedded in self-cure acrylic resin to form acrylic blocks to undergo the fracture resistance test, all teeth were loaded in a universal testing machine with a static loading perpendicular to the long axes of the teeth till fracture then the forces for failure were recorded (Newton), tabulated and statically analyzed.
Restricted
Impact of rotation VS reciprocation motion on the configuration of curved root canals during retrieval of gutta percha filling : (In vitro comparative study) /
Mohammed, Ismail Mohammed Ismail,; Supervisor : Abeer Hashem Mahran, Mohammed Alaa Fakhr. Includes Arabic Summary.
Restricted
The effect of the ultraconservative access cavity on the homogeneity of root canal obturation : “An in vitro study” /
Imam, Abdelaziz Mohamed,; Supervisor : Abeer Abdel Hakeem El Gendy, Mohamed Fakhr. Includes Arabic Summary.Supervisor
Restricted
Impact of access cavity design and root canal taper on fracture strength of endodontically treated mandibular premolars : (an in-vitro study) /
Naguib, Mariam Awny Boshra,; Supervisor : Nihal Sabet, Amr Bayomi, Islam Shawky.
Restricted
The Effect of two body wear on CAD/CAM PEEK against monolithic zirconia, lithium disilicate and tooth enamel : "An in vitro study''
Bekhiet, Ahmed Khaled Gamil,; Supervisor : Hesham Katamish, Tarek Salah Morsi, Talaat Samhan.
Restricted
Effect of LED, Plasma Arc and CaCl2 on the solubility and water sorption of conventional GIC : (An in-Vitro Study) /
Amer, Nahla Ali Sayed,; Supervisor : Mohamed Mahmoud Abdelmohsen, Dina Wafik Elkassas, Kosmas Tolidis. Includes Arabic Summary.
Restricted
Effect of cyclic loading on fracture resistance of 3Y-TZP and gradient 3Y-TZP/5Y-TZP veneered zirconia based fixed partial denture : (in-vitro study) /
Negm, Rana Mahmoud,; Supervisor : Tamer Elhamy Shokry, Lomaya Ghanem.
Restricted
Accuracy of artificial intelligence technology in detecting the number of root canals in human mandibular first molars : A diagnostic accuracy experimental study /
Abd-Elsamie, Salma Khaled Kamel,; Supervisor : Hossam Tewfik, Alaa Diab, Mohamed Alaa Fakhr. Includes Arabic Summary.
Artificial intelligence (AI) is revolutionizing various fields of medicine, including dentistry. In endodontics, AI has the potential to improve diagnostic accuracy, treatment planning, and overall patient care. There is minimal scientific evidence concerning the accuracy of the detection of the number of canals using Artificial Intelligence. The aim of this study is to define the accuracy of an Artificial Intelligence (AI) Software to detect the number of root canals in the mandibular first molars compared to the standard clinical method under magnification and to the gold standard using a Cone Beam Computed Tomography (CBCT). In addition, this study aims to determine the morphological variations in cases where the AI failed to detect all the canals. Thirty-Five patients presented to MIU dental clinics with mandibular first permanent molars requiring root canal treatment were selected according to the eligibility criteria. Teeth that met the criteria had pre-operative periapical x-rays taken. Adequate case and medical history were taken. Detection of the number of root canals was achieved by 3 methods: Radiographically using the CBCT as the gold standard, clinically using the DOM and using an AI software. After signing the informed consent, the patients underwent CBCT imaging using Endo mode to minimize the radiation exposure before treatment initiation. CBCT was coded based on the patients file numbers instead of names. The number of canals identified was recorded in a pre formed information guide. Using randomization software, the 35 patients were divided up amongst 6 post graduate students at random. A dental operating microscope was used to prepare the access cavity for each patient. In order to minimize the radiation dose to the patient, the CBCT was given to the postgraduate student after the number of canals was recorded. This helped to prevent inter-treatment periapical radiographs as working length X-rays. After that, the principal researcher, who was blind to the outcomes of the CBCT stage, carried out the AI stage individually. The Diagnocat AI Software was used to upload the CBCT images, and CBCT segmentation and deep learning techniques were employed. Next, the software's total number of canal identifications was recorded. The gathered data was divided into three groups based on the canal detection method into: CBCT Findings, Clinical Findings and AI Findings. Cases containing canals that were missed by the AI software had additional examination of the morphological features of each tooth from the CBCT. The six cases in which the AI software successfully detected the number of canals were randomly selected as a comparative group. For both groups the following features were included: the inter-orifice distance was measured in order to accomplish this, the length of the root, Vertucci classification type and the length of the Canal division measured from the apex and CEJ. In addition, from the axial cut of the CBCT, the inter-orifice distance was measured in the same manner between the canals that were not detected by the AI. Afterward, the mean inter-orifice distance was calculated for both the failed and successful cases. Those measurements were utilized to calculate the percentage of canal unity within the entire root length associated to the missed canals. The degree of accuracy was 100% for the DOM, 100% for the CBCT and 82.86% for the AI. It was clear that application of AI software didn’t detect the exact number of canals in all cases. The AI software detected the correct number of canals in only 29 cases. The use of DOM and CBCT detected all canals in all the 35 cases. Another analysis was done to relate the inaccuracies of the software to the morphology of the wrong cases detected. It was evident that the inter-orifice distance for the incorrectly detected cases was less than that of the cases correctly detected. Added to that, the percentage of canal unity was analyzed for the distal canals, which is the measure of the unity of both distal canals along the entire length of the root. The greater the union between both distal canals, the less likely the AI software will distinguish them as separate canals. The average percentage of canal unity of the incorrectly detected cases was greater than 50% and the percentage of canal unity for the correctly detected cases was a maximum of 20% which allowed the software to detect two distal canals.
Restricted
Computed Tomographic assessment of a noval NiTi system in Retreatment procedure : (an in Vitro study) /
Abd El Wahab, Maram Hossam El-Din,; Supervisor : Nihal Sabet, Mohamed Mokhtar Nagi.
Patients typically need a root canal treatment when there is inflammation or infection in the root canals. Root canal treatment is an oftenstraightforward procedure to relieve pulpal pain and render the tooth function and asymptomatic. During root canal treatment, an endodontist carefully removes the pulp inside the tooth, cleans, disinfects and shapes the root canals, and obturate to seal the space. A three-dimensional obturation of the system of the root canal through the whole length of the canal is one important goal under which successful root canal therapy can be achieved. Many obturation techniques have been introduced to obtain a threedimensional filling of the root canal system and increase the quality of the apical seal, although root canal treatment has high success rate when conducted appropriately, failures could happen that are usually accompanied by badly treated canals. Unfortunately, failure of endodontic treatment is mainly caused by intraradicular infection. This endodontic infection should be treated by removal of the filling material and retreatment procedure There are many techniques that have been proved to be effective in the removal of the materials that fill the root canal from root canal system, such as the usage of endodontic hand files, Gates Glidden burs,Nickel Titanium rotary devices, laser, ultrasonic devices ,heated device, as well as the usage of assistant solvents. Traditionally, the usage of hand files in the elimination of gutta percha in the presence or absence of solvent can be a boring, time consuming procedure particularly if the root filling material is perfectly compressed Recently, a novel rotary nickel titanium system which were tailored for retreatment processes have been included to endodontics field. The 1 Introduction protaper universal retreatment (PTUR) system is one of these systems, Protaper Universal retreatment files which was designed to be used in sequence to remove filling material with Rotation motion. None of the retreatment instruments examined the reciprocation motion on retreatment procedure, hence in this study Wave one and wave one gold were used as a retreatment instrument. Recently, using of Cone-beam computed tomography (CBCT) in endodontics became a common technique .It showed a great competence in comparison with other traditional radiographic techniques in many cases such as the assessment of the root canal system and resorptive lesions. In addition it helps in the diagnosis of apical periodontitis, and in designing a plan for treatment of endodontic surgery. Although a great deal of useful information can be obtained from Cone Beam Computed Tomography, we must also consider that Cone Beam Computed Tomography is a radiographic technique with an exposure dose that is significantly greater than intraoral radiography. To avoid overuse or abuse of Cone Beam Computed Tomography, several guidelines have been published Therefore, this work was accomplished to examine the efficacy of Wave One and Wave One Gold in retreatment procedure
Restricted
Micro-shear strength of hybrid ceramics : the effect of different surface treatments and universal adhesives in vitro study /
Yacoub, Tarek Anwar Ibrahim,; Supervisor : Ashraf Hassan Mokhtar, Hanaa Hassan Zaghloul.
Restricted
Root canal cleanliness following mechanical retrieval of different bioceramic based obturating techniques : (An in-vitro study) /
Nour, Sara Wael Ahmed Hassan,; Supervisor : Abeer Abdelhakim Elgendy, Amr Bayoumi. Includes Arabic Summary.
Restricted
The effect of silver nano-irrigant and erbium chromium: YSGG laser on the smear layer removal and microhardness of root canal dentine : in-vitro study /
Aboudoura, Moustafa Mohamed Samy Moustafa,; Supervisor : Reem Ahmed Lutfy Abdel Rahman, Ahmed Hussein Abu El-Ezz. Includes Arabic Summary.