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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pop-colas and dental corrosion

Borjian, Amirfirooz January 2011 (has links)
Introduction: Manufactured Colas are consumed universally as soft drinks. Evidence about the acid contents of Cola-beverages and its effects on teeth is rare. Aim: To assess: (i) cola acidity and buffering capacity in vitro, (ii) tooth erosion after swishing with colas in vivo (iii) scanning electron microscopic effects on teeth of colas, and tooth-brush abrasion, and (iv) report a clinical case of erosion from cola consumption. Materials and Methods: (i) We measured six commercially available pop ‘Cola-beverages', pH and buffering capacities using a pH-Mettler Automatic Titrator, with weak solution of Sodium Hydroxide. (ii) Two cohorts, one with teeth, the second without teeth rinsed with aliquots of Cola for 60 seconds. Swished cola samples tested for calcium and phosphorus contents using standardized chemical analytical methods. (iii) Enamel, dentine and the enamel-cemental junction from unerupted extracted wisdom teeth were examined with a scanning electron microscope after exposure to colas, and tested for tooth-brush abrasion and (iv) a clinical case of pop-cola erosion presentation, are all described. Results: Comparisons among pop-colas tested in vitro reveal high acidity with very low pH. Buffering capacities in milliliters of 0.5M NaOH needed to increase one pH unit, to pH 5.5 and pH 7 are reported. Rinsing in vivo with pop-cola causes leaching of calcium from teeth; SEM shows dental erosion, and pop-cola consumption induces advanced dental erosion and facilitates abrasion. Conclusions: (i) Pop-Cola acid activity is below the critical pH 5.5 for tooth dissolution, with high buffering capacities countering neutralization effects of saliva; (ii) calcium is leached out of teeth after rinsing with pop-colas; (iii) SEM evidence explains why chronic exposure to acid pop-colas causes dental damages; and (iv) a clinical case of pop-cola erosion confirms this. Key Words: Acid, Attrition, Abrasion, Beverages, Buffering, Calcium, Cola, Coca-Cola, Diet-Coke, Diet-Pepsi, Diet-Selection, Erosion, Frangibles, Pepsi, Selection-Cola, Teeth. / Introduction : Il se consomme des boissons gazeuses de type cola partout dans le monde. Les éléments de preuve concernant la teneur en acide des boissons de type cola et ses effets sur les dents sont rares. Objectif : (i) Mesurer l'acidité et le pouvoir tampon du cola in vitro, (ii) mesurer l'érosion dentaire à la suite d'un rinçage in vivo avec des colas, (iii) mesurer les effets du cola sur les dents au moyen d'un microscope électronique à balayage, ainsi que l'abrasion découlant du brossage, et (iv) présenter un cas clinique d'érosion issue de la consommation de cola. Matériel et méthodes : (i) Nous avons mesuré le pH et les pouvoirs tampons de six boissons gazeuses commerciales de type cola au moyen d'un pH-mètre et d'un titrimètre automatique de Mettler, avec une solution faible d'hydroxyde de sodium. (ii) Deux groupes, l'un dont les membres avaient des dents et l'autre non, se sont soumis à un rinçage de 60 secondes avec une aliquote de cola. La teneur en calcium et en phosphore des échantillons se rapportant au rinçage avec du cola a été mesurée au moyen de méthodes normalisées de chimie analytique. (iii) L'émail, la dentine et la jonction émail-cément des troisièmes molaires extraites n'ayant pas fait leur éruption ont été examinés au microscope électronique à balayage après l'exposition au cola, et ont été soumis à un test d'abrasion par brosse à dents, et (iv) un cas clinique d'érosion attribuable au cola est présenté. Résultats : Les comparaisons entre les colas testés in vitro révèlent une acidité élevée avec un pH très bas. Les pouvoirs tampons en millilitres de NaOH 0.5 M devaient augmenter d'une unité de pH, et les mesures de pH 5.5 et pH 7 sont rapportées. Le rinçage in vivo avec du cola entraîne la décalcification des dents. En effet, les examens réalisés au microscope électronique à balayage montrent une érosion dentaire. Par conséquent, la consommation de colas provoque une érosion dentaire avancée et contribue à l'abrasion. Conclusions : (i) L'activité acidifiante du cola se situe sous le seuil critique de pH 5.5 pour la dissolution dentaire, et présente un pouvoir tampon élevé qui annule les effets neutralisants de la salive; (ii) le calcium est éliminé des dents après le rinçage avec les colas; (iii) les analyses réalisées au microscope électronique à balayage expliquent pourquoi l'exposition chronique à l'acidité des colas entraîne une fragilité dentaire ; et (iv) un cas clinique d'érosion due au cola vient confirmer les résultats obtenus. Mots clés : Acide, Attrition, Abrasion, Boissons, Tamponnage, Calcium, Cola, Coca-Cola, Coke diète, Pepsi diète, Sélection diète, Érosion, Fragile, Pepsi, Sélection cola, Dents.
2

Access to dental services for people using a wheelchair

Rashid-Kandvani, Farnaz January 2013 (has links)
Studies show that people with disabilities, including people using a wheelchair, have more untreated dental problems and tend to use dental services less than the rest of the population. Despite this discrepancy, the nature of these difficulties and the shape of their dental care pathways have not been studied. Consequently, this study was undertaken to address this gap, with the goal of better understanding the difficulties that people using a wheelchair experience in accessing dental services and to identify solutions to facilitate their access to quality dental services. This research was structured to effectively study and advocate for possible solutions to this problem. It is based on a participative approach, culminating from the many partnerships we developed with people with physical disabilities, dental professionals, and dental educators. These partners formed an advisory committee that provided advice and direction during various stages of the project. Furthermore, we adopted a qualitative descriptive research design: a particularly appropriate way of exploring phenomena about which very little is known. Through a purposeful sampling strategy, we recruited 13 adults living in Montreal. All of the participants used a wheelchair because of various mobility impairments. We conducted a semi-structured individual interview with each of them and analyzed transcripts using an inductive thematic method. The resulting interviews illustrate that people with physical disabilities face a wide range of barriers in accessing dental services. These difficulties were classified into 11 challenges faced throughout the dental care pathway. These challenges begin with the tasks of finding an accessible dentist, being accepted by the dentist as a patient, and organizing the appointment and its related transportation. After overcoming these challenges, people using a wheelchair can experience further difficulties entering the building, moving inside the clinic, and interacting with the staff. Moreover, additional difficulties occur during treatment sessions: transferring into the dental chair may be difficult or sometimes impossible; once in the dental chair, people may experience physical pain, muscular spasms or other uncomfortable sensations. Time may also be an issue as sessions may last longer than expected. Finally, financial barriers related to the cost of dental treatment proved to be a recurrent concern. Overall, our study conclusively shows that people using a wheelchair face discrimination in accessing dental services. The challenges we identified culminate in the creation of oral health inequalities as some people with physical disabilities eventually give up using these ill-adapted services. We firmly believe that it is the responsibility of any given society to remove the existing barriers that are faced by people using a wheelchair. Accordingly, this study provides a series of recommendations that will initiate and maintain this change. These recommendations are targeted at multiple sectors of society, including the government, the dental profession, dental faculties, and organizations that represent people with physical disabilities. / Les études montrent que les personnes à mobilité réduite ont plus souvent des problèmes dentaires non traités que le reste de la population; en outre, elles ont tendance à moins utiliser les services dentaires. Malgré cette situation problématique, on connait très mal le parcours thérapeutique des personnes à mobilité réduite et les difficultés que ces dernières rencontrent dans l'accès aux services. La présente étude a été entreprise pour remédier à cette lacune. Notre but était de mieux comprendre les difficultés que les personnes utilisant un fauteuil roulant rencontrent dans l'accès aux services de soins dentaires, et d'identifier des solutions pour remédier à leurs problèmes. Cette recherche est basée sur une approche participative, et sur des partenariats avec des personnes à mobilité réduite, des professionnels dentaires et des éducateurs dentaires. Ces partenaires ont formé un comité consultatif qui nous a conseillé lors des différentes étapes du projet. En outre, nous avons adopté une méthodologie de recherche qualitative descriptive, approche qui est particulièrement appropriée pour explorer les phénomènes dont on sait très peu. Grâce à une stratégie d'échantillonnage ciblé, nous avons recruté 13 adultes vivant à Montréal. Tous les participants utilisaient un fauteuil roulant en raison de divers problèmes de mobilité. Nous avons effectué une entrevue individuelle semi-structurée avec chacun d'eux et analysé les transcriptions en utilisant une méthode thématique inductive. Les entrevues révèlent que les personnes à mobilité réduite rencontrent de multiples barrières dans l'accès aux services dentaires. Celles-ci ont été classées en 11 difficultés rencontrées dans leur parcours de soins dentaires. Elles débutent avec le défi de trouver un dentiste accessible, d'être accepté par le dentiste, d'organiser le rendez-vous et le transport. Après avoir surmonté ces défis, les personnes utilisant un fauteuil roulant peuvent éprouver des difficultés supplémentaires pour entrer dans le bâtiment, se déplacer à l'intérieur de la clinique, et interagir avec le personnel. En outre, des difficultés se produisent pendant les séances de traitement: être transféré dans le fauteuil dentaire peut être difficile ou parfois impossible; une fois dans le fauteuil dentaire, les gens peuvent éprouver des douleurs physiques, des spasmes musculaires ou d'autres sensations désagréables; le temps peut également être un problème car les sessions durent souvent plus longtemps que pour les autres personnes. Enfin, les obstacles financiers liés au coût des traitements dentaires s'avèrent des préoccupations récurrentes. Globalement, notre étude montre que les personnes utilisant un fauteuil roulant sont victimes de discrimination dans l'accès aux services dentaires. Les défis que nous avons identifiés peuvent générer des inégalités de santé buccodentaire si les personnes avec un handicap physique renoncent aux services des professionnels dentaires. Nous croyons fermement qu'il est de la responsabilité de la société de supprimer les multiples obstacles auxquels font face les personnes utilisant un fauteuil roulant. Par conséquent, la présente étude propose une série de recommandations qui s'adressent à plusieurs secteurs de la société: le gouvernement, la profession dentaire, les facultés dentaires et les organisations qui représentent les personnes à mobilité réduite.
3

Regenerative Dental Enamel

Fletcher, Jane January 2010 (has links)
No description available.
4

Benign design for dental restorations

Richardson, Charlotte Jane January 1999 (has links)
No description available.
5

Digital analysis of staining properties of clear aesthetic brackets

Rykiss, Jared 14 September 2011 (has links)
AIM: To analyze staining properties of aesthetic brackets. MATERIAL & METHODS: A total of 400 tooth-coloured brackets from 10 brands 5 ceramic and 5 plastic) were investigated. Cumulative effects of staining agents were analyzed at simulated light and heavy consumption levels. Study groups were immersed in the staining agents consecutively at 37°C. The control group was exposed to artificial saliva. Samples were analyzed digitally to obtain the L*, a*, and b* (lightness, red-green, and yellow-blue) colour readings. Using these values total colour change (ΔE*) was also calculated. A general linear model (ANOVA) test was used for statistical comparisons. RESULTS: Significant differences were observed in L*, and b* values of ceramic brackets at all consumption levels (p≤.0001). All values had significant differences amongst the plastic brackets (p≤.0001), except for L* with heavy exposure. Total ΔE* values for ceramic and plastic brackets were 11 and 26, respectively. CONCLUSIONS: Both plastic and ceramic brackets showed changes in colour when exposed to staining agents, with plastic brackets being the most affected.
6

Digital analysis of staining properties of clear aesthetic brackets

Rykiss, Jared 14 September 2011 (has links)
AIM: To analyze staining properties of aesthetic brackets. MATERIAL & METHODS: A total of 400 tooth-coloured brackets from 10 brands 5 ceramic and 5 plastic) were investigated. Cumulative effects of staining agents were analyzed at simulated light and heavy consumption levels. Study groups were immersed in the staining agents consecutively at 37°C. The control group was exposed to artificial saliva. Samples were analyzed digitally to obtain the L*, a*, and b* (lightness, red-green, and yellow-blue) colour readings. Using these values total colour change (ΔE*) was also calculated. A general linear model (ANOVA) test was used for statistical comparisons. RESULTS: Significant differences were observed in L*, and b* values of ceramic brackets at all consumption levels (p≤.0001). All values had significant differences amongst the plastic brackets (p≤.0001), except for L* with heavy exposure. Total ΔE* values for ceramic and plastic brackets were 11 and 26, respectively. CONCLUSIONS: Both plastic and ceramic brackets showed changes in colour when exposed to staining agents, with plastic brackets being the most affected.
7

The change in oral health related-quality of life among adolescents and their families after orthodontic treatment

Sawan, Huda 09 August 2012 (has links)
Objective: Assess the changes in oral health-related quality of life (OHRQoL) of adolescents and their parents after overjet reduction. Materials and Methods: 53 patients between the ages of 11-18 years with increased dental overjet (≥ 6mm) and their parents were selected, of which 28 were pre- and 25 were post-treatment with dental overjet reduced to within normal limits. The data collection instrument was the Child Oral Health Quality of Life (COHQoL) Questionnaire. Results: Adolescents and their parents reported poorer quality of life before orthodontic treatment than after. The improvement in oral health-related quality of life was statistically significant for all health domains except for the social well-being domain. Parental reports on (OHRQoL) were in agreement with their children’s. No statistically significant differences were evident in (OHRQoL) between pre- and post-treatment groups. Conclusions: Adolescents with increased dental overjet ≥6mm experienced substantial psycho-social impacts. Adolescents with increased overjet can accurately recall the initial negative effects of the original malocclusion on their lives, even after a time lapse of five years. Orthodontic treatment significantly improves the perceived quality of life of orthodontic patients and their parents
8

The change in oral health related-quality of life among adolescents and their families after orthodontic treatment

Sawan, Huda 09 August 2012 (has links)
Objective: Assess the changes in oral health-related quality of life (OHRQoL) of adolescents and their parents after overjet reduction. Materials and Methods: 53 patients between the ages of 11-18 years with increased dental overjet (≥ 6mm) and their parents were selected, of which 28 were pre- and 25 were post-treatment with dental overjet reduced to within normal limits. The data collection instrument was the Child Oral Health Quality of Life (COHQoL) Questionnaire. Results: Adolescents and their parents reported poorer quality of life before orthodontic treatment than after. The improvement in oral health-related quality of life was statistically significant for all health domains except for the social well-being domain. Parental reports on (OHRQoL) were in agreement with their children’s. No statistically significant differences were evident in (OHRQoL) between pre- and post-treatment groups. Conclusions: Adolescents with increased dental overjet ≥6mm experienced substantial psycho-social impacts. Adolescents with increased overjet can accurately recall the initial negative effects of the original malocclusion on their lives, even after a time lapse of five years. Orthodontic treatment significantly improves the perceived quality of life of orthodontic patients and their parents
9

Determination of the accuracy of semi-automatic and fully automatic 2d lateral cephalometric analysis programs

Playfair, Nicholas Grant 19 August 2013 (has links)
AIM: To evaluate the accuracy of current semi-automatic and fully automatic 2D lateral cephalometric analysis programs. MATERIALS AND METHODS: 60 lateral cephalometric radiographs were randomly selected and grouped based their skeletal malocclusions to form 3 equal groups of 20 Class I, 20 Class II and 20 Class III. These radiographs were then analyzed via traditional hand-based analysis. The values obtained from this method of analysis were compared to 4 subsequent methods of analysis. These consisted of semi-automatic analysis using Dolphin Imaging software, semi-automatic analysis using Kodak Orthodontic Imaging software, fully automatic analysis using Kodak Orthodontic Imaging software and fully automatic analysis combined with limited landmark changes using Kodak Orthodontic Imaging software. RESULTS: ICC tests were completed to compare the gold standard hand-based analysis to the 4 subsequent methods. The values obtained from semi-automatic Dolphin and Kodak Orthodontic Imaging software were found to be comparable to hand-based analysis. Whereas, the values obtained from the fully automatic mode of Kodak Orthodontic Imaging software were not found to be comparable to hand-based analysis. CONCLUSIONS: Digital cephalometric programs can be used as an accurate method when performing lateral cephalometric analyses. The fully automatic mode of these programs should only be used as a support to diagnosis and not as a diagnostic tool.
10

Cephalometric evaluation of dental class II correction using the Xbow® appliance in different facial patterns

Chana, Randeep S. 31 July 2013 (has links)
Objective: To determine the magnitude of the skeletal and dental movements in subjects with different facial patterns following Class II correction using the XbowTM appliance. Materials and Methods: A retrospective sample of 134 subjects exhibiting Class II malocclusions was used. Subjects were categorized into three growth types according to pre-treatment cephalometric variables (MPA and Y-axis), which yielded 27 brachycephalic, 70 mesocephalic, and 37 dolichocephalic subjects. A ANOVA test statistic was used to investigate the differences between the three facial groups at pre and post-treatment time points. Results: Dental changes induced by the XbowTM appliance included: proclination of the lower incisors (L1-MP 7.3-12.3o±1.0o), protrusion of the lower incisors (L1-APo 2.1-3.8mm±0.3mm), mesial movement of the mandibular first molar (5.5-6.9mm±0.7mm) and retrusion of the maxillary incisor (2.4-3.1mm±0.4mm). Retroclination of the maxillary incisor (U1-PP 0.2-0.8o±0.7o) and distal movement of the maxillary molar (0.4-0.7mm±0.3mm) were not significantly influenced by XbowTM treatment. Reduction of the skeletal Class II relationship was represented by a significant decrease of the Wits value (2.4-4.5mm±0.5mm) in all three groups. The p value was considered significant at <0.05. Conclusions: Class II correction with the XbowTM appliance is the result of mesial movement of the mandibular molar, proclination/protrusion of the lower incisor and retrusion of the upper incisor. Skeletal correction must be validated by more than one cephalometric variable. Facial growth pattern appears to be unrelated to the amount of dental movement and there is a trend for pronounced dental movements of the lower incisor in brachycephalic patients.

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