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 artificial intelligence technology in detecting number of root canal of human maxillary first molar : Diagnostic Accuracy Experimental Study /
Nofal, Sara Ragab,; Supervisor : Nihal Ezzat Sabet, Ahmed Hussein Abu El-Ezz. Includes Arabic Summary.
Restricted
Accuracy of artificial intelligence technology in detecting number of root canals in human mandibular first molars obturated and Indicated for retreatment : (Diagnostic accuracy experimental study) /
Alkady, Albaraa Samir,; Supervisor : Ahmed Abdelrahman Hashem, Ahmed Ghobashy, Ahmed Hussein. Includes Arabic Summary.
Statement of problem: Failure to disinfect and to locate all canals is a major reason for root canal primary and secondary failures, which may lead to periapical periodontitis. Cone beam computed tomography (CBCT) is considered the gold standard in canal detection although its use must be justified beforehand due to its high radiation dose. Using artificial intelligence (AI) software may enhance canal detection and avoid human error in interpreting CBCT images. Aim of the study: To evaluate the accuracy of new AI technology for detecting root canals in mandibular first molars retreatment cases in comparison to dentist clinical access cavity and CBCT imaging. Materials and methods: Thirty-five patients with obturated lower first molar(s) referred for retreatment was participated in this study. After a pre-treatment periapical x-ray to aid practitioner in access cavity formation a CBCT was performed for all cases. Stage 1: CBCT scans performed to all participants were randomly distributed and observed by the principle investigator and supervisors and the number of canals found was recorded. Stage 2: patients were randomly distributed on 6 post graduate students* students enrolled in the endodontic master’s program at MIU* students were then performed access cavity, the number of canals found will be recorded. Stage 3: CBCT images were uploaded to AI software, and the number of canals detected was be recorded. Data collected will be compared using 3 groups: Group 1: CBCT with co supervisor interpretation the control group Group 2: clinically after performing access cavity. Group 3: CBCT with the AI technology. All cases that failed to be detected by the AI software were then evaluated for more morphological features that may influence the accuracy of AI software.
Restricted
Accuracy of artificial intelligence technology in detecting number of root canals of obturated human maxillary second molars indicated for retreatment : diagnostic accuracy experimental study /
Hegab, Ayman Alaa Hussein,; Supervisor : Nihal Sabet, Ahmed Khalaf. Includes Arabic Summary.
Statement of the Problem: Endodontic treatment has always been a challenging procedure and failure to detect all canals and completely disinfecting the root canal system could lead to an endodontic failure. In retreatment cases, the endodontic procedure becomes more challenging and tricky requiring high knowledge and skills. Artificial intelligence software makes it easier in analysis of CBCT scans reducing dentist errors and improving treatment success rates. Aim of the study: The aim of the study is to evaluate the accuracy and reliability of an artificially intelligent software that would analyze, aid, support, and help the endodontist to detect the correct number of root canals of 35 obturated maxillary second molars indicated for retreatment in comparison to both Cone Beam Computed Tomography and Clinical observation. Materials and methods: This study included 35 Patients with Maxillary Second obturated molars indicated for re-treatment who underwent a pre-treatment CBCT, while only a pre-treatment periapical radiograph was taken to aid in access cavity preparation in the clinical stage. The study was levelled into three stages. CBCT Stage: Pre-operative CBCT scans of the patients were taken and randomly assigned to 2 co-supervisors who segmented, interpreted, and recorded the number of canals on a pre-formed information guide. Clinical Stage: A clinical stage where the enrolled patients were randomly distributed upon 6 researchers. Researchers then performed access cavities under DOM. The number of orifices found was recorded in a preformed information guide. AI stage: CBCT scans was uploaded to AI software by researcher and Number of canals found by the software were recorded. The results of the first two stages were then compared to the findings of the third stage to determine software accuracy. Cases with missed canals by the AI software underwent further evaluation of tooth morphological features, to determine the reason for the software’s detection failure. Results: There was a statistically significant difference between detected number of canals by the three methods (P-value = 0.018). AI showed higher percentage of two, three canals and lower percentage of four canals detection. The CBCT stage and the clinical stage showed complete agreement in their findings, however the CNN program inaccurately identified the proper number of canals in three cases. To evaluate the relationship between these cases and the potential impact of morphological variation on the AI software, the canal type was determined using Vertucci's classification. It was found that all three unsuccessful cases had a type II canal. There was an insignificant link between the canal morphology and the AI software's incapacity to detect canals. When the AI program was unable to accurately identify the proper number of canals, the average ratio of canal unity was around 60%. This means that around two-thirds of the canal length was considered as one canal, while only one-third of the length was considered as two separate canals.
Restricted
Accuracy of artificial intelligence technology in detecting root canal number and morphology in maxillary second molars : A diagnostic accuracy experimental study /
Sami, Hebah Mohamed Eltaher Monir Mohamed,; Supervisor : Hossam Tewfik, Alaa Diab, Ahmed Hassan Ibrahim. Includes Arabic Summary.
A comprehensive understanding of root canal space anatomy is essential for clinicians to be able to treat and prevent apical periodontitis, the main reason for endodontic therapy. Approximately 40% of failed endodontic therapy is due to missed canals, indicating lack of clinical thoroughness in treatment. Maxillary second molars present with varying internal morphologies in different individuals, which is affected by age, genetics, and gender. Inadequacy in detecting these variations during treatment is reflected by the upper molars showing the top rates of endodontic treatment failures. Although many techniques have previously been employed to facilitate canal detection, CBCT is currently considered the gold standard in clinical canal structure exploration, as it has the potential to change initial diagnoses and treatment plans in almost 50% of cases. However, due to problems such as interobserver differences in interpreting scans and the need for training clinicians to read CBCT scans, a special interest has emerged in artificial intelligence (AI) technology to help overcome these problems. In this study, the accuracy of AI software in detection of canal number was compared to the radiographic detection using CBCT and the clinical detection using a DOM in maxillary second molars. Thirty-five patients with maxillary second molars requiring primary RCT with signs and symptoms of irreversible pulpitis or necrotic teeth that are restorable were selected. The number of canals were first detected radiographically from the CBCT by experienced endodontists and recorded, then 6 postgraduate students performed an EAC under the DOM and ultrasonic troughing and recorded canal number detected. Finally, the CBCT was uploaded to the AI software to detect the canal number. AI software accuracy was determined by comparing its results to the results of the 2 other groups. Further analysis of the AI generated report was done to assess the cases that canal number was incorrectly detected to evaluate the possible morphological features that might have been the reason for the incorrect detection. Another six cases in which AI software successfully detected the number of canals were randomly selected as a comparative group. Four main features were additionally assessed thoroughly, namely, the inter orifice distance, length of the mesiobuccal root, level of canal division from the root apex, and canal anatomy based on Vertucci classification. The method of analysis of the CBCT for data extraction for this assessment was standardized for all cases and done at the level of the CEJ. Results showed that the CBCT showed the highest percentage accuracy (100%) in the interpretation of canal morphology and number, while the clinical detection followed closely (94.2%), and the AI software was the lowest percentage accuracy (82.8%) amongst the 3 modalities. Its level of confidence was generally high with 79% of the correct cases and 50% of the incorrect cases being in the highest confidence level respectively. The four additional features assessed showed that the average inter-orifice distance is lower in the incorrect group and the average percentage canal unity was much higher. This indicated that the software is less likely to detect the MB2 canal if it is unified with the MB1 for more than 50% of the entire canal length, and that the smaller the inter-orifice distance the less likely is the software in detecting the MB2 canal. The canals’ Vertucci type did not seem to influence the software’s ability to detect the canal number. In general, the results of the AI software were promising, even if it is currently less than the other 2 modalities used, since the nature of the AI software with deep learning strategies spontaneously improves with the greater amount of data input to it with time. Although many studies agreed with the results of this study regarding the percentage accuracy of AI software, however some studies showed differing results that demonstrated higher accuracy of the AI software. This could be attributed to the differences in the study design, the type of AI software used, and the sample size. However, all studies agree that the future of AI software use in endodontic canal detection is highly encouraging.
Restricted
Accuracy of artificial intelligence technology in detecting the number of canals in human maxillary first molars indicated for retreatment : Diagnostic accuracy experimental study /
Sholkamy, Mostafa Sherif,; Supervisor : Abeer Hashem Mahran, Ahmed Hussein Abu El-Ezz. Includes Arabic Summary.
Statement of Problem: Missed canals are one of the main causes of failure of primary root canal treatment. CBCT is considered the gold standard in morphology detection. Problems of using CBCT include high radiation dose and practitioner inability to interpret images. Artificial Intelligence (AI) technology may help overcome these problems. Aim: The aim of this study was to evaluate the accuracy of novel AI software in detecting the number of canals in 36 maxillary first molars indicated for retreatment, as well as, to compare it with accuracy of CBCT and clinical assessment. Materials and Methods: 36 Patients referred to MIU dental clinic for retreatment of upper first molars underwent pre-treatment CBCT, while only pretreatment periapical radiograph will be taken to aid in access cavity preparation in the clinical stage. The study included 3 stages: CBCT Stage: Pre-operative CBCT scans of the patients were taken and randomly assigned to 2 co-supervisors who upon scan segmentation recorded the number of canals on a pre-formed information guide. Clinical Stage: A clinical stage where the enrolled patients were randomly distributed upon 6 researchers. Practitioners then performed access cavities on the teeth under DOM. The number of orifices found was recorded on a preformed information guide. AI stage: CBCT images will be uploaded to AI software by primary investigator and Number of canals found by the software were recorded. Results of the first two stages were then compared to the findings of the third stage to determine software accuracy. Cases with missed canals by the AI software underwent further evaluation of tooth morphological features, to determine the reason for the software’s detection failure.
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
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
Accuracy of surgical guides fabricated using two different 3D printers for prosthetically driven implant surgery : An in-Vitro Study /
Semary, Amr Mohamed Abd Elfattah,; Supervisor : Hesham Katamish, Tarek Salah-Eldin Morsi, Mostafa Hussein.
Restricted
Accuracy of working Models and Marginal Fit of tooth Supported Provisional Dental Prosthesis Fabricated by Three Dimensional Printing Compared to CAD/CAM Milling System : (In Vitro Study) /
Sidhom, Marina Fayek Fathallah,; Supervisor : Ihab El-Sayed Mosleh, Hanaa Zaghloul.
Restricted
Antibacterial Effect of a Diode Laser in the Eradication of Enterococcus feacalis, and Smear Layer Removal in Root Canal of Infected Teeth : (An in Vitro Study)
Hussein, Dina Nashaat Hassan,; Supervisor : Salma El Ashry, Ahmed Mostafa Ghobashy.
The definitive goal of root canal treatment is to obtain a root canal system free of irritants, as any remaining microorganisms can cause persistent inflammation in the periradicular tissues. Success of endodontic therapy depends on complete elimination of pathogenic micro flora from the root canal system. Enterococcus faecalis is the most common bacteria associated with persistent endodontic infections. It is a facultative gram-positive anaerobic coccus that has the ability to exist in root canals without the support of other microorganisms. It has the ability to infect the whole length of dentinal tubules within a few days, and is considered difficult to eradicate. It can also survive harsh environmental factors, and form biofilms that are difficult to detach. Biofilm disruption and root canal disinfection are the most important steps during root canal treatment. Sodium hypochlorite is one of the most commonly used irrigating solutions in endodontics. The antibacterial efficiency of sodium hypochlorite solution against E. faecalis is well known to be affected by its concentration and contact time. Adjunctive techniques of root canal disinfection have been proposed, and the introduction of lasers in endodontics is one. Lasers have dramatically improved the effectiveness and success rate of root canal treatment. According to several studies, the use of laser systems for endodontic disinfection provides an opportunity to reduce the problems concerning the difficult access of instruments and irrigants to certain areas of root canals, mainly at the apical ramifications. It has been recognized that near-infrared lasers (810 nm to 1340 nm) have greater depth of penetration when compared to the penetration power of chemical disinfectants, which allows for better bactericidal effect in deeper dentin layers. The use of photosensitizing agents has been proposed in endodontics used with methods such as ‘photodynamic therapy’ (PDT) or “photoactivated disinfection” (PAD). Photosensitizing solutions have better wetting capabilities as they have lower surface tension than sodium hypochlorite. Photosensitizer concentration, light intensity and time of application have to be precise in order to achieve optimal results. Laser thermal effect can generate damage to the dentin walls. Several studies investigated the laser-induced morphological effects on root canal walls. When they are used on dry tissue, near-infrared lasers produce characteristic thermal effects. Morphological alterations of the dentinal wall occur, and the smear layer is only partially removed. Dentinal tubules are primarily closed as a result of melting of the inorganic dentinal structures. Employing the correct parameters and treatment protocol for laser use in root canal disinfection and bacterial elimination can help replace the conventional syringe irrigation methods of disinfection, reduce the morphological alteration of root canal dentin, and improve the treatment outcome.
Restricted
Assessment of fracture resistance of endodontically treated molars restored with endocrowns fabricated by two different materials : in-vitro study /
Bassyouni, Hanan Salah El Din,; Supervisor : Hussein Gomaa, Inas Mohsen El Zayat, Ahmed Mohamed Hoseny Fayed. Includes Arabic Summary.
This in vitro study was conducted to assess the fracture resistance of endodontically treated molars restored with endocrowns fabricated by pressed lithium disilicate and nanohybrid resin composite cemented by conventional etch and rinse resin cement. Forty mandibular second molars were collected according to the inclusion and exclusion criteria. Teeth were divided into four equal groups; Group (1): sound molars as a negative control (sound), Group (2): unrestored endodontically treated molars with occluso-mesial cavities as a positive control (unrestored), Group (3): endodontically treated molars with occluso-mesial cavities and lithium disilicate endocrowns (LDS) and Group (4): endodontically treated molars with occluso-mesial cavities and nanohybrid resin composite endocrowns (NRC). Teeth of unrestored, LDS and NRC were endodontically treated. All groups were embedded in self-cure acrylic resin blocks. Teeth of LDS, and NRC groups received a standardized occluso-mesial cavities. Each tooth of LDS and NRC groups were prepared for endocrown restorations and scanned using digital intraoral scanner. Casts were designed on a software and printed using 3D printer. For LDS group, restorations were designed using CAD/CAM software with same anatomy, 2 mm occlusal heights and 80 μm cement space. Wax patterns were milled, then sprued and invested to produce lithium disilicate endocrowns using heat pressed technique. For NRC group, four coats of 20 μm die spacer were coated on the 3D printed casts. Increments (2 mm) of nanohybrid composite were applied until building the entire shape and thickness using the silicon index. Nanohybrid resin composite endocrowns were removed after initial curing and subjected to additional dry heat curing. Lithium disilicate endocrowns were surface treated using 9.5% hydrofluoric acid followed by application of silane coupling agent. Nanohybrid resin composite endocrowns were sandblasted using 50 μm aluminum oxide particles followed by silanization. While teeth surfaces were etched using 37% phosphpric acid and total-etch adhesive. All endocrowns were cemented using conventional dual cure resin cement. Teeth of all groups were mounted to universal testing machine with a 6 mm diameter ball applying load perpendicularly to the long axis of the tooth to test the fracture resistance. Maximum force required for fracture were recorded in Newton. Fracture modes were also identified under stereomicroscope and divided into repairable fracture which extends above the CEJ and irreparable fractures which extends below the CEJ. Results of this study showed a statistically significant difference between groups (p< 0.001). Sound teeth presented the highest mean fracture resistance followed by NRC then LDS with statistically insignificant difference between the three groups. Unrestored teeth showed the least mean fracture resistance with a statistically significant difference to the other three groups. Mean percent recovery in fracture resistance of both test groups and fracture modes of all groups were also evaluated. Results showed that NRC has higher mean percent recovery than that of LDS, which emphasize the ability of NRC to restore 91.08% of the fracture strength lost after endodontic treatment and occluso-mesial cavity preparation. While LDS restored only 75.66%. On the other hand, Sound teeth showed the highest percentage of samples with repairable fractures (80%) followed by NRC (70%). While LDS showed unfavorable fractures of (80%).
Restricted
Bioactive Cement versus Resin Cement Regarding the Perceived Shade of E-Max Restorations : (An In Vitro Study) /
Nagy, Amira Gehad,; Supervisor : Omaima Elmahallawy, Lomaya Ghanem
Esthetics is becoming the main concern for patients and professionals. Demands for creating a natural appearing smile has increased as it reflects youth and acceptance. The goal of esthetic dentistry is to restore teeth to meet the natural form, biocompatibility and appearance. To create a dental restoration that gives a natural looking requires accurate replication of size, shape, surface texture, contouring, translucency and color of natural dentition. Shade is an essential parameter that attracts attention of patients, they judge and accept their dental restorations based on shade matching especially in the anterior esthetic zone. For dental restoration with acceptable shade, translucency and fluorescence it should match that of natural dentition to mimic the vitality. In the past decades, porcelain fused to metal fixed prosthesis was the material predominantly used to restore teeth. But, unfortunately the metal layering acts as a barrier for light transmission giving the restoration dark opaque appearance. The introduction of metal free restorations all-ceramic restorations, have proved to be an excellent alternative for porcelain fused to metal. These restorations utilize more conservative preparation because of the continuous improvements in their mechanical, physical properties and processing methods. Ceramic type, thickness, shade, firing temperature and bonding affects the final appearance of restoration. Lithium disilicate was launched in 1998 by Ivoclar Vivadent; it is one of the most famous glass- ceramics. It has adequate mechanical properties and offers attractive esthetic quality. One of the most important factors that affect the color of dental restorations is the cement used. Type, thickness, curing method and shade affects the perceived shade of the restoration and it’s stability over time. Resin cements are widely used for cementation of lithium disilicate as it bonds chemically to underlying glass- ceramic increasing strength and longevity of dental restoration. Furthermore, it has a clinically accepted color effect and stability. Newly introduced bioactive dental cement with ionic resin matrix is claimed to mimic the physical and chemical properties of natural teeth. In addition, it releases and recharge of calcium, phosphate and fluoride. It would be challenging to investigate the shade of lithium disilicate samples cemented with bioactive cement and comparing it with samples cemented with resin cement.
Restricted
Bioactive Cement versus Resin Cement Regarding the Perceived Shade of E-Max Restorations : (An In Vitro Study)
Nagy, Amira Gehad
Esthetics is becoming the main concern for patients and professionals. Demands for creating a natural appearing smile has increased as it reflects youth and acceptance. The goal of esthetic dentistry is to restore teeth to meet the natural form, biocompatibility and appearance. To create a dental restoration that gives a natural looking requires accurate replication of size, shape, surface texture, contouring, translucency and color of natural dentition. Shade is an essential parameter that attracts attention of patients, they judge and accept their dental restorations based on shade matching especially in the anterior esthetic zone. For dental restoration with acceptable shade, translucency and fluorescence it should match that of natural dentition to mimic the vitality. In the past decades, porcelain fused to metal fixed prosthesis was the material predominantly used to restore teeth. But, unfortunately the metal layering acts as a barrier for light transmission giving the restoration dark opaque appearance. The introduction of metal free restorations all-ceramic restorations, have proved to be an excellent alternative for porcelain fused to metal. These restorations utilize more conservative preparation because of the continuous improvements in their mechanical, physical properties and processing methods. Introduction Ceramic type, thickness, shade, firing temperature and bonding affects the final appearance of restoration. Lithium disilicate was launched in 1998 by Ivoclar Vivadent; it is one of the most famous glass- ceramics. It has adequate mechanical properties and offers attractive esthetic quality. One of the most important factors that affect the color of dental restorations is the cement used. Type, thickness, curing method and shade affects the perceived shade of the restoration and it’s stability over time. Resin cements are widely used for cementation of lithium disilicate as it bonds chemically to underlying glass- ceramic increasing strength and longevity of dental restoration. Furthermore, it has a clinically accepted color effect and stability. Newly introduced bioactive dental cement with ionic resin matrix is claimed to mimic the physical and chemical properties of natural teeth. In addition, it releases and recharge of calcium, phosphate and fluoride. It would be challenging to investigate the shade of lithium disilicate samples cemented with bioactive cement and comparing it with samples cemented with resin cement.
Restricted
Bond Strength and Adaptability of Bioceramics Root Canal Obturating System /
EL-Said, Nancy Magdy Mohamed,; Supervisor : Salma Hassan El-Ashry, Amira Galal Ismail.
Obturation of root canal complex is the most essential step in successful root canal therapy. It is described as "the three dimensional closure of the entire root canal system adapted to the cement-dentinal junction as close as possible". For an appropriate and acceptable root canal fluid tight seal; Small volume of sealers which are biologically compatible are used along with gutta percha core at apical, lateral and coronal sections of root canal system. New obturating material has been developed in Endodontics to enhance the sealing of the root canal system. Bio-ceramics were introduced; bioceramics are calcium silicate based material which exhibit excellent biocompatibility properties due to their similarity with biological hydroxyapatite, .bioceramics also have the ability to achieve excellent hermetic seal, form a chemical bond with the tooth structure and have good radio-opacity antibacterial properties as a result of precipitation in situ after setting. Total fill as one of the advances in bioceramics; it is bioceramic impregnated gutta percha with a premixed bioceramic sealer. It was claimed that the calcium phosphate-based system made for a more consistent and tighter adaptation to the dentinal walls as compared to gutta-percha. Total Fill BC sealer has higher qualities and handling abilities that prevents its shrinkage during setting and hardens in the presence of moisture. The wetting ability of the sealer is due to the small particle size, hydro-philicity and low contact angle; these properties enable the sealer to easily distribute in the dentinal tubules. It also shows a significant expansion of 0.20 percent. These characteristics create a gapless chemical bond between the sealer and dentinal walls. It is worth to study and evaluate the bond strength, the adaptation and effect of different volume of sealers on these properties.
Restricted
Bond strength and adaptation of Nano biodentine as a repair material for furcation perforations : (an in vitro study) /
Sedky, Khaled Mohamed,; Supervisor : Nihal E. Sabet, Mohamed A. Fakhr.
Restricted
Chemico-mechanical retrieval of two bioceramic based obturation techniques : (In vitro) /
Awad, Passant Gaber,; Supervisor : Kareem Mostafa Al batouty, Mohamed Mokhtar Nagy, Ahmed Hussein Abuelezz. Includes Arabic Summary.
Restricted
Clinical evaluation of self-adhesive bulk-fill composite versus conventional Nano-hybrid composite in cervical cavities : A randomized controlled clinical trial /
El-Shazly, Riham Kamal El-Desouky,; Supervisor : Mohamed Mahmoud AbdelMohsen, Inas Mohsen Gamil El-Zayat. Includes Arabic Summary.
Restricted
Color Change and Postoperative Hypersensitivity of Discolored Teeth Pretreated with Microabrasion before Bleaching using light versus chemically activated agents : Randomized Controlled Trial /
Shawky, Aya Khaled Mohamed,; Supervisor : Olfat ElSayed Hassanein, Asmaa Ali Mohamed Yassen, Inas Mohsen El-Zayat.
Dental aesthetics is considered an important concern that many patients seek for, aiming to reach an attractive smile. Tooth discoloration can be classified as the main etiological factor for esthetic problems in dental patients. It can be correctly evaluated and managed by detecting its type, location and intensity. There are two types of discoloration. Superficial extrinsic which is resulted from tea, coffee, smoking, wine and poor oral hygiene and it is considered the common type of dental staining. The second type is the intrinsic discoloration which is described as deep stains involving the inner dentin layer of the teeth and resulted from internal trauma , diseases , medications like tetracycline , over exposure to fluoride and aging .(1) Many techniques aid in improving tooth color such as whitening tooth pastes, professional cleaning and polishing by abrasive pastes, whitening strips and gels, enamel microabrasion by using abrasives and acids and bleaching techniques either internal or external. (2) Nowadays dental bleaching is one of the most dental procedures that can greatly overcome the problem of teeth discoloration. Generally, there are three different bleaching approaches including in office bleaching, at home bleaching and over the counter bleaching whitening products. Both in office and at home bleaching techniques are done under the dentist’s supervision in contrast to over the counter bleaching products. Each approach varies in concentrations of the bleaching agent and contact time of exposure. (3) Bleaching agents used in these bleaching approaches are hydrogen peroxide and carbamide peroxide which act as active ingredients. In office bleaching technique requires high concentration of hydrogen peroxide (25-35%) and short treatment time. On the other hand at home bleaching technique requires a low concentration of 10% carbamide peroxide which contains only 3% hydrogen peroxide and long treatment time. Despite, the great advancement in the field of dental bleaching, a lot of patients still suffer from heavy stained teeth that cannot be treated by applying the traditional high concentration bleaching agent even if it is combined with home bleaching. Hence, trials are being done to overcome this problem by enamel pretreatment using different acids or combined acids and abrasive particles as in the microabrasion technique. This technique aids to remove the porous surface enamel layer and any entrapped stains and increases the enamel surface energy that aids for more penetration of bleaching agents through these created micro pores. Enamel microabrasion can be done either by using acidic and abrasive agents such as (6% hydrocloric acid and silica or 37% phosphoric acid with pumice). It was claimed that this treatment is safe when combined with bleaching to achieve perfect smile appearance. Attaining and maintaining a lighter tooth color is the main goal of tooth bleaching, yet color regression usually happens after using hydrogen peroxide bleaching agent by time .(5) Thus, color change should be assessed immediately after bleaching and over an extended time period. Tooth color is a complex phenomenon that can’t be detected correctly by visual shade selection. Different color measuring devices are used for more accuracy such as spectrophotometer and colorimeter. Tooth is a biological unit in which other considerations rather than esthetics should be taken into consideration. Dental bleaching cannot be considered a successful technique when it leads to painful teeth. Sensitivity is one of the most common patients complain after vital tooth bleaching procedure. Hence, different desensitizing agents were added to some bleaching gels such as (fluoride and potassium nitrate) to overcome this problem. So that it was of value to evaluate the use of surface pretreatments as micro abrasion before bleaching on color change and teeth sensitivity.
Restricted
Color masking effect of ultra-opaque resin cement with different ceramic systems : (An in-vitro study) /
AL-Masry, Lydia Mahmoud,; Supervisor : Tamer Elhamy Shokry, Talaat Samhan. Includes Arabic Summary.
Cement criteria considered as one of the important factors that influence shade on dental restorations. The perceived shade of restoration by the naked eye affected by cement type, thickness, shade and curing method. Aim of study was to test the effectiveness of the Ultra-Opaque luting cement (Vita Adiva IA-Cem) compared to the conventional one (Breeze) on masking the metal Ni-Cr substrate covered with three ceramic materials and evaluating its color stability after thermocycling. A total of 60 disc-shaped specimens were machined out of three types of monolithic CAD/CAM ceramic blocks: IPS e.max CAD, Vita Suprinity, and Katana ultra-translucent zirconia; 20 samples for each material. Shade A2 MT was chosen for the three materials. A total of 60 Ni-Cr metal disc shaped specimens were manufactured using a customized teflon mold with dimension 10mm X 1mmto and lost wax technique be adhesively cemented to ceramic one. CAD/CAM ceramic blocks were milled into cylinders with dimensions 10 mm diameter and 14 mm long (for e.max and vita suprinity) and 11 mm diameter and 14 mm long (For Katana zirconia). The cylinders were then sliced into discs with 1 mm thickness by using diamond sawing machine. The IPS e.max and Vita suprinity samples were crystalized and glazed in one step inside a firing furnace, Katana samples were also sintered and glazed in one step inside a sintering oven as well. For IPS e.max CAD and Vita Suprinity specimens, surface treatment was done using 9% hydrofluoric acid& rinsed for 1 minute under water spray and then silane coupling agent was applied for 1 minute. For Katana specimens, zirconia primer was used to apply one drop on the zirconia specimens before cementation as well. The metal disc specimens were then placed inside another custom made split teflon mold machined with the dimensions of 10mm X 2.1 mm and then the cement was applied on it using mixing tip to be cemented to the ceramic one under standard weight of 1 Kg. A portable Spectrophotometer was used to measure the baseline color of the specimens before cementation, after cementation of ceramic specimens to metal one and after being subjected to thermocycling process. Color masking and color changes results (DE) were obtained using equation DE = [(D L*)2 + (D a*)2 +(D b*)2] ½.
Restricted
Color stability of three different types of monolithic CAD/CAM esthetic restorations after exposure to artificial accelerated aging : (An In-Vitro Study).
Abdelhalim, Ahmed Magdy Mohamed,; Supervisor : Tamer Elhamy Shokry, Talaat Samhan.