published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / abstract / toc / Dentistry / Master / Master of Philosophy

Indiana University-Purdue University Indianapolis (IUPUI) / Molar Hypomineralization (MH) of the first permanent molars (FPMs) and the second primary molars (SPMs) is a common developmental defect of enamel, with global prevalence of 14% and 5% respectively. Children with MH represent a special pediatric population because their affected molars have extreme susceptibility to enamel breakdown, decay and tooth sensitivity. Although the problem of MH has been described almost twenty years ago mainly through reports from Europe, there is very little information about the problem from the USA. In this dissertation, MH was explored both from the perspectives of pediatric dentists’ (PDs) and at population level. The majority of the survey respondents perceived MH prevalence to be <10% in their clinical practice (62%). The most cited clinical challenge in managing MH teeth was “long-term success of restorations” (79%). When analyzed individually, responses differed significantly for different demographics and educational characteristics of the respondents (p<0.05). At population level, MH of the FPMs (Molar Incisor Hypomineralization (MIH) cohort: 337 schoolchildren, average age 9 years) and of the SPMs (Hypomineralized Second Primary Molar (HSPM) cohort: 423 schoolchildren, average age 7 years) had prevalence estimates of 13% and 6% respectively. In the MIH cohort, water fluoridation or non-Hispanic Black race/ethnicity was significantly associated with higher collective prevalence of enamel defect (EDs) (P<0.05), but not with the prevalence of MH of the FPMs. In the HSPM cohort, race/ethnicity was significantly associated with higher overall prevalence of EDs of SPMs, but not with the HSPM prevalence. Older age group (>10 years), living in central Indiana, and water fluoridation were significantly associated with higher overall prevalence of EDs (P<0.01), but not with the HSPM prevalence. Caries experience was significantly higher in children with MH of FPMs and/or SPMs than in the group without MH. We concluded that USA pediatric dentists’ respondents were well aware of the MH problem, but demonstrated discrepancies in different aspects of the MH problem. At population level, MIH and HSPM were common presentation with prevalence estimates similar to the global figures. Certain demographic characteristics were significantly associated with the overall prevalence of the enamel defects of the examined teeth.

Objetivo: Registrar a prevalência, a localização e as características dos defeitos no esmalte nos incisivos em ambas dentições de pacientes com fissura labiopalatina e avaliar sua possível recorrência. Modelo: Estudo Longitudinal. Local de Execução: Setor de Odontopediatria do Hospital de Reabilitação de Anomalias Craniofaciais - Universidade de São Paulo (HRAC-USP), Bauru - Brasil. Participantes: 48 pacientes, regularmente matriculados no HRAC-USP, com fissura transforame incisivo unilateral (FTIU) e bilateral (FTIB), de ambos os sexos, de 7 a 13 anos que participaram de uma avaliação prévia da dentição decídua em 2000/2002. Metodologia: A freqüência, a extensão e a localização das alterações do esmalte na face vestibular dos dentes em ambas dentições foram avaliadas clinicamente, segundo o índice DDE, após testes intra e inter examinador. Resultados: As alterações do esmalte foram encontradas em ambas dentições em 24 pacientes (50%). Em indivíduos com FTIU a recorrência foi de 53,8% com maior severidade em 50% dos dentes e 89,5% em pacientes com FTIB apresentando-se em 94% igual ou mais severa na dentição permanente. Conclusões: As alterações no esmalte apresentaram recorrência em ambos os tipos de fissuras, com maior ocorrência e gravidade nas bilaterais. Estes aspectos associados aos fatores secundários que envolvem as fissuras, como tensão cicatricial do lábio e maior acúmulo de placa, podem favorecer o aparecimento de doenças bucais, sendo o seu conhecimento essencial para que o cirurgião-dentista realize procedimentos mais adequados. / Objective: To record the prevalence, location and characteristics of enamel defects on incisors in both deciduous and permanent teeth of patients with cleft lip and palate, investigating their possible recurrence.Design: Longitudinal study.Setting: Pediatric Dentistry sector, HRAC-USP. Participants: 48 patients registered at HRAC/USP, with complete unilateral or bilateral cleft lip and palate, of both genders, aged 7 to 13 years; the patients had been previously submitted to evaluation of their deciduous teeth in 2000 to 2002. Methods: The frequency, extent and location of enamel alterations on the buccal aspect of deciduous and permanent teeth were evaluated by the DDE index, after evaluation of intra- and inter-examiner agreement. Results: Enamel alterations were observed in both deciduous and permanent teeth in 24 patients (50%). Recurrence was observed in 53.8% of individuals with complete unilateral cleft lip and palate, with greater severity in 50% of permanent teeth; and in 89.5% of patients with complete bilateral cleft lip and palate, with greater severity in the permanent dentition in 94% of cases. Conclusions: Recurrence of enamel alterations was observed in both types of clefts, with greater occurrence and severity in bilateral clefts. These aspects, associated to secondary factors related to cleft lip and palate, such as lip scar and greater plaque accumulation, may increase the appearance of oral diseases; knowledge on these disturbances is fundamental to allow the dental professional to adopt more adequate procedures.

Made available in DSpace on 2014-06-11T19:23:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-01Bitstream added on 2014-06-13T20:30:26Z : No. of bitstreams: 1 silva_cmc_me_arafo.pdf: 737324 bytes, checksum: 20d53f99fba0b62be56dfb55aa23f762 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho, dividido em tres estudos, foi avaliar: (1) a influencia da utilizacao de diferentes fontes de luz e metodos de fotoativacao sobre o grau de conversao e a contracao de polimerizacao de uma resina composta nanoparticulada; (2) a influencia da utilizacao dos diferentes metodos de fotoativacao, disponibilizados por aparelhos LED de 2a geracao, sobre a contração volumetrica das resinas compostas microhibrida e nanoparticulada e (3) as propriedades termicas e o grau de conversao das resinas compostas microhibrida e nanoparticulada, submetidas aos diferentes metodos de fotoativacao disponibilizados por aparelhos LED de 2a geracao. No primeiro estudo, o grau de conversao (GC) foi avaliado pelo metodo da espectroscopia infravermelha transformada de Fourier (FT-IR) e as forcas de contracao (C) mensuradas em maquina de ensaios universal (EMIC). Os dados obtidos para o GC e C foram analisados estatisticamente pelo teste da analise de variancia (ANOVA), sendo que para as forcas de contracao, a correcao de Welch e o teste Tamhane também foram empregados. No segundo estudo, a contracao volumetrica foi avaliada por um mecanismo de video e imagem (AcuvolR/Bisco) e os dados obtidos foram analisados estatisticamente pelos testes ANOVA e Tukey. No terceiro estudo, o metodo da calorimetria exploratoria diferencial foi empregado para avaliar a temperatura de transicao vitrea (Tg) e de degradacao dos materiais e o GC por FTIR. Os dados relativos ao GC foram analisados estatisticamente pelos testes ANOVA e Tukey. Os resultados demonstraram diferencas na contracao de polimerizacao de acordo com o metodo de fotoativacao empregado. No primeiro e segundo estudos, mesmo empregando diferentes metodologias, o metodo de fotoativacao continuo apresentou os maiores valores de contracao. Por outro lado,o GC nao foi influenciado pelo método... / The aim of this work, divided into three studies, was evaluate: (1) the influence of different light sources and photo-activation methods on degree of conversion and polymerization shrinkage of a nanocomposite resin; (2) the influence of different photo-activation methods, available by the 2nd generation LED light-curing units, on the volumetric shrinkage of microhybrid and nanocomposite resins and (3) thermal properties and degree of conversion of microhybrid and nanocomposite resins submitted to different photo-activation methods available by 2nd generation LED light-curing units. In the first study, degree of conversion (DC) was evaluated by Fourier transform infrared spectroscopy (FT-IR) and shrinkage forces (S) were measured in a universal testing machine (EMIC). The data obtained for DC and S were analyzed by Analysis of Variance test (ANOVA) and for S Welch’s correction and Tamhane’s tests were also employed. In the second study, volumetric shrinkage was evaluated by video-imaging device (AcuvolR/Bisco) and data were analyzed by ANOVA and Tukey’s test. In the third study, differential scanning calorimetry was used in order to observe glass transition temperature (Tg) and degradation peak of the materials and DC was evaluated for FT-IR. The DC data were analyzed by ANOVA and Tukey’s test. The results showed differences in the polymerization shrinkage according to photo-activation method employed. In the first and second studies, the continuous photo-activation methods presented the highest values for shrinkage even though different methodologies were used to assess. Moreover, DC was not influenced by the photo-activation method but was influenced by light sources. The lowest DC values were observed for halogen light-curing unit. In the second study beyond the influence of the photo-activation method on the volumetric shrinkage... (Complete abstract click electronic access below)

Orientador: Angela Cristina Cilense Zuanon / Banca: Rosana de Fátima Possobon / Banca: Lourdes Santos Pinto / Resumo: O objetivo deste trabalho, dividido em tres estudos, foi avaliar: (1) a influencia da utilizacao de diferentes fontes de luz e metodos de fotoativacao sobre o grau de conversao e a contracao de polimerizacao de uma resina composta nanoparticulada; (2) a influencia da utilizacao dos diferentes metodos de fotoativacao, disponibilizados por aparelhos LED de 2a geracao, sobre a contração volumetrica das resinas compostas microhibrida e nanoparticulada e (3) as propriedades termicas e o grau de conversao das resinas compostas microhibrida e nanoparticulada, submetidas aos diferentes metodos de fotoativacao disponibilizados por aparelhos LED de 2a geracao. No primeiro estudo, o grau de conversao (GC) foi avaliado pelo metodo da espectroscopia infravermelha transformada de Fourier (FT-IR) e as forcas de contracao (C) mensuradas em maquina de ensaios universal (EMIC). Os dados obtidos para o GC e C foram analisados estatisticamente pelo teste da analise de variancia (ANOVA), sendo que para as forcas de contracao, a correcao de Welch e o teste Tamhane também foram empregados. No segundo estudo, a contracao volumetrica foi avaliada por um mecanismo de video e imagem (AcuvolR/Bisco) e os dados obtidos foram analisados estatisticamente pelos testes ANOVA e Tukey. No terceiro estudo, o metodo da calorimetria exploratoria diferencial foi empregado para avaliar a temperatura de transicao vitrea (Tg) e de degradacao dos materiais e o GC por FTIR. Os dados relativos ao GC foram analisados estatisticamente pelos testes ANOVA e Tukey. Os resultados demonstraram diferencas na contracao de polimerizacao de acordo com o metodo de fotoativacao empregado. No primeiro e segundo estudos, mesmo empregando diferentes metodologias, o metodo de fotoativacao continuo apresentou os maiores valores de contracao. Por outro lado,o GC nao foi influenciado pelo método... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this work, divided into three studies, was evaluate: (1) the influence of different light sources and photo-activation methods on degree of conversion and polymerization shrinkage of a nanocomposite resin; (2) the influence of different photo-activation methods, available by the 2nd generation LED light-curing units, on the volumetric shrinkage of microhybrid and nanocomposite resins and (3) thermal properties and degree of conversion of microhybrid and nanocomposite resins submitted to different photo-activation methods available by 2nd generation LED light-curing units. In the first study, degree of conversion (DC) was evaluated by Fourier transform infrared spectroscopy (FT-IR) and shrinkage forces (S) were measured in a universal testing machine (EMIC). The data obtained for DC and S were analyzed by Analysis of Variance test (ANOVA) and for S Welch's correction and Tamhane's tests were also employed. In the second study, volumetric shrinkage was evaluated by video-imaging device (AcuvolR/Bisco) and data were analyzed by ANOVA and Tukey's test. In the third study, differential scanning calorimetry was used in order to observe glass transition temperature (Tg) and degradation peak of the materials and DC was evaluated for FT-IR. The DC data were analyzed by ANOVA and Tukey's test. The results showed differences in the polymerization shrinkage according to photo-activation method employed. In the first and second studies, the continuous photo-activation methods presented the highest values for shrinkage even though different methodologies were used to assess. Moreover, DC was not influenced by the photo-activation method but was influenced by light sources. The lowest DC values were observed for halogen light-curing unit. In the second study beyond the influence of the photo-activation method on the volumetric shrinkage... (Complete abstract click electronic access below) / Mestre

Objetivo: Registrar a prevalência, a localização e as características dos defeitos no esmalte nos incisivos em ambas dentições de pacientes com fissura labiopalatina e avaliar sua possível recorrência. Modelo: Estudo Longitudinal. Local de Execução: Setor de Odontopediatria do Hospital de Reabilitação de Anomalias Craniofaciais - Universidade de São Paulo (HRAC-USP), Bauru - Brasil. Participantes: 48 pacientes, regularmente matriculados no HRAC-USP, com fissura transforame incisivo unilateral (FTIU) e bilateral (FTIB), de ambos os sexos, de 7 a 13 anos que participaram de uma avaliação prévia da dentição decídua em 2000/2002. Metodologia: A freqüência, a extensão e a localização das alterações do esmalte na face vestibular dos dentes em ambas dentições foram avaliadas clinicamente, segundo o índice DDE, após testes intra e inter examinador. Resultados: As alterações do esmalte foram encontradas em ambas dentições em 24 pacientes (50%). Em indivíduos com FTIU a recorrência foi de 53,8% com maior severidade em 50% dos dentes e 89,5% em pacientes com FTIB apresentando-se em 94% igual ou mais severa na dentição permanente. Conclusões: As alterações no esmalte apresentaram recorrência em ambos os tipos de fissuras, com maior ocorrência e gravidade nas bilaterais. Estes aspectos associados aos fatores secundários que envolvem as fissuras, como tensão cicatricial do lábio e maior acúmulo de placa, podem favorecer o aparecimento de doenças bucais, sendo o seu conhecimento essencial para que o cirurgião-dentista realize procedimentos mais adequados. / Objective: To record the prevalence, location and characteristics of enamel defects on incisors in both deciduous and permanent teeth of patients with cleft lip and palate, investigating their possible recurrence.Design: Longitudinal study.Setting: Pediatric Dentistry sector, HRAC-USP. Participants: 48 patients registered at HRAC/USP, with complete unilateral or bilateral cleft lip and palate, of both genders, aged 7 to 13 years; the patients had been previously submitted to evaluation of their deciduous teeth in 2000 to 2002. Methods: The frequency, extent and location of enamel alterations on the buccal aspect of deciduous and permanent teeth were evaluated by the DDE index, after evaluation of intra- and inter-examiner agreement. Results: Enamel alterations were observed in both deciduous and permanent teeth in 24 patients (50%). Recurrence was observed in 53.8% of individuals with complete unilateral cleft lip and palate, with greater severity in 50% of permanent teeth; and in 89.5% of patients with complete bilateral cleft lip and palate, with greater severity in the permanent dentition in 94% of cases. Conclusions: Recurrence of enamel alterations was observed in both types of clefts, with greater occurrence and severity in bilateral clefts. These aspects, associated to secondary factors related to cleft lip and palate, such as lip scar and greater plaque accumulation, may increase the appearance of oral diseases; knowledge on these disturbances is fundamental to allow the dental professional to adopt more adequate procedures.

Identification of an appropriate material capable of enamel remineralization to fill a cavity after the removal of dental tissue is a new field of dental research. Elucidation of the associated factors involved in enamel defects remain in question including the mechanisms of enamel hypoplasia as well as improvement needed in our current treatment models. The purpose of this thesis is to evaluate the factors associated with enamel defects, to understand the mechanism by which they evolve, as well as look into a new method of treatment called, fluorapatite cement. This new treatment has shown promising affects to improve our current treatment to restore enamel defects, however, to find the best treatment we must understand the foundations of enamel and how defects arise. Enamel is the strongest tissue in the body because it must maintain resistance to factors such as bacterial adhesion, acidity, and temperature. Enamel defects can present as white spots, discoloration, or deep fissures in the enamel due to a disturbance that occurred during tooth oogenesis. Enamel hypoplasia provides favorable conditions for the early development of caries and the retention of plaque, which can progress and reach deep into the enamel and the dentin and cause sensitivity. Our current treatment is efficient and has been used for decades, however, requires the surrounding health enamel to be removed. This is a disadvantage and has encouraged scientists to continue researching for an effective way to remineralize enamel and avoid the loss of healthy enamel. Diseases such as coeliac disease have an influence on the formation of enamel that lead to defects. A recent study investigated if dentists can play a role in early diagnosis of diseases including coeliac disease by examining patients for enamel defects. The study discovered that there was not a significant difference in oral evaluations to determine upon early diagnosis, however, they did conclude that there was pattern in the types of defects that were found in coeliac patients. Specifically, grade I and II defects were found on the anterior teeth of coeliac patients, therefore, the study still recommends seeing the dentist for oral exams as well as supports further study. To understand the mechanism of how defects arise, scientists studied first permanent molars in children during their first three years of life with factors including, institutionalization, gender, medications, and diseases. Studies showed that females have a two-fold risk for enamel defects over males and institutionalized children have a three-to-four-fold risk of enamel defects. To improve our current treatment and avoid loss of healthy enamel and a costly procedure, scientists are looking into the use of hydroxyapatite (HA), a natural occurring mineral in our body, to create a possible new synthetic enamel called fluorapatite (FA) cement. Research analyzed fluorapatite cement compared to natural enamel and found that FA cement has a stronger resistance to acidity with a weight loss of 0.75% wt% compared to enamel with 1.2% and greater resistance to bacterial adhesion than natural enamel by three times. FA cement was also found to have more stability and higher cellular activity than hydroxyapatite. As for safety for dental application, FA cement and HA were placed in simulated body fluid to test for cytotoxicity levels, and none were present. Therefore, FA cement has a promising approach to restore enamel defects effectively and conveniently. Further research is recommended to understand the association of females and institutionalized children with enamel defects versus all children in a larger study group. The current reported results from fluorapatite cement are very promising. This cement can allow an inexpensive and more efficient method of treatment due to its abilities to remineralize enamel that even stronger than natural enamel. The recent hydroxyapatite and fluoride toothpaste products show the growing research that is being put into this idea of creating a synthetic enamel with our current mineral hydroxyapatite. This thesis supports the idea that FA cement has the potential as an alternative to current treatment for enamel defects and hopefully will be ready to undergo a clinical trial in the near future.

No / Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as Cuspal Enamel Hypoplasia.

no / This was to study an archaeological population of subadult teeth in 17th and 18th century skeletal material from a London (England) cemetery for enamel defects including molar-incisor-hypomineralisation (MIH).Methods: Dentitions of 45 sub-adults were examined using standard macroscopic methods and systematically recorded. A total of 557 teeth were examined with a *5 lens and photographed. Ages of the individuals were estimated from their dental crown and root development stages and not from charts that combine tooth eruption with development stages. The dental age of the individual and the approximate age of onset of enamel defects was then calculated on the basis of the chronological sequence of incremental deposition and calcification of the enamel matrix. Affected enamel was graded macroscopically as: - Mild: <30% of the tooth¿s enamel surface area visibly disrupted (this encompasses the entire range reported in most other studies), Moderate: 31-49% of the tooth's enamel surface area visibly disrupted and Severe: >50% of the tooth's enamel surface area visibly disrupted. Results: Of the total number of individuals 41 (93.2%) showed signs of enamel developmental dysplasia or MIH, 28 of them showing moderate or severe lesions of molars, primary or permanent (63.6% of the sample). Incisors and canines, though surviving much less often, showed episodes of linear hypoplasia. Conclusion:The extensive lesions seen on many of the molars displayed cuspal enamel hypoplasia (CEH). Many of these teeth also exhibited Molar Incisal Hypomineralisation (MIH).