Made available in DSpace on 2017-07-24T19:22:30Z (GMT). No. of bitstreams: 1 AndreaMaria.pdf: 1410970 bytes, checksum: d3cd44a617db57ae1d8d688b76d38f1e (MD5) Previous issue date: 2004-07-21 / The use of antimicrobial agents for dental biofilm formation chemical control is common after toothbrushing. Some authors have speculated a possible interaction between the clorhexidine molecule and laurel sulfate detergent present in dentifrices. The purpose of this cross-sectioned, double-blinded study was to evaluate the influence of the time interval between the usage of a dentifrice and the aministration of clorhexidine digluconate at 0.12% in vivo. The sample consisted of 20 individuals with no periodontal disease. All received during the three experimental phases the following treatment: G1 – mouthrinse with clorhexidine digluconate at 0.12% solution for 30 minutes after the removal of the dentifrice from the oral cavity; G2 - mouthrinse with clorhexidine digluconate at 0.12% solution immediately after the removal of the dentifrice from the oral cavity; G3 – mouthrinse with a placebo solution immediately after the removal of the dentifrice from the oral cavity. Scores were obtained for every subject by classifying the mechanical control of plaque formation using the Turesky Plaque Index (1970) and Gingival Inflammation Index of Mombelli (1987). Collected data was grouped and analyzed with the non-parametric Friedman test (p<0,05). Significant statistical difference between the three groups was found where group 1 presented the least overall scores followed by group 2 and 3. With the methodology used, it can be concluded that the time between the usage of dentifrice and mouthrinse with clorhexidine digluconate at 0.12% can influence the efficiency in the chemical control of the dental biofilm formation. / Na prática odontológica, os agentes antimicrobianos de controle químico do biofilme dental têm sido utilizados após procedimentos de escovação. Alguns autores têm apontado uma possível interação entre a molécula de clorexidina e o detergente lauril sulfato de sódio presente nos dentifrícios. O objetivo deste estudo cruzado e duplo-cego foi avaliar “in vivo” a influência do intervalo de tempo entre a utilização do dentifrício e a administração de digluconato de clorexidina a 0,12% sobre os índices de placa (TURESKY, 1970) e de sangramento gengival (MOMBELLI, 1987) em indivíduos sem doença periodontal, na ausência do controle mecânico da placa dental. Vinte voluntários receberam nas 3 fases experimentais os seguintes tratamentos: G1- bochecho com solução de digluconato de clorexidina a 0,12% trinta minutos após a remoção do dentifrício da cavidade bucal; G2- bochecho com solução de digluconato de clorexidina a 0,12% imediatamente após a remoção do dentifrício da cavidade bucal; G3- bochecho com solução placebo imediatamente após a remoção do dentifrício da cavidade bucal. Os dados coletados foram organizados e submetidos ao teste não paramétrico de Friedman (p<0,05). Os resultados mostraram diferenças estatisticamente significantes entre os 3 grupos experimentais, sendo os menores escores de placa para o grupos G1, seguido do G2 e G3. De acordo com a metodologia empregada, foi possível concluir que o intervalo de tempo entre a utilização do dentifrício e o bochecho com o digluconato de clorexidina a 0,12% pode influenciar a eficácia do controle químico do biofilme dental.

Herpes vírus humanos são patógenos amplamente distribuídos na população mundial e, recentemente, tem se estudado um possível envolvimento desses vírus na etiologia da doença periodontal. Indivíduos HIV positivos (HIV+) têm mostrado uma maior prevalência desses vírus e, a imunossupressão induzida pelo HIV é conhecida por facilitar a reativação desses microorganismos. Desse modo, o presente estudo teve como objetivo determinar a presença dos vírus Herpes simples tipo 1 (HSV-1), Citomegalovírus (HCMV) e Epstein-Barr vírus tipo 1 (EBV-1), relacionando-os com a presença de bactérias periodontopatogênicas como: Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis) e Tannerella forsythia (T. forsythia) em pacientes HIV+ com doença periodontal. Foram coletadas amostras de placa subgengival, saliva e sangue capilar de vinte e sete indivíduos HIV+ com periodontite crônica (HIV-p) e 23 indivíduos HIV+ com gengivite (HIV-g). A detecção das espécies bacterianas e dos herpes vírus foi realizada pela técnica de Reação em cadeia da polimerase (PCR) e Nested PCR, respectivamente. A análise estatística mostrou que para o grupo HIV-p, EBV-1 e T. forsythia apresentaram maior prevalência nas amostras de placa subgengival (70.4% e 51.8%, respectivamente) e saliva (81.5%, 40.7%, respectivamente) do que no sangue (22% e 0, respectivamente) (p<0.005 e p<0.0001, respectivamente). A bactéria P. gingivalis foi mais freqüente na placa subgengival (77.7%) em relação à saliva (25.9%) e sangue (25.9%) (p<0.0001). No grupo HIV-g, P. gingivalis e HCMV apresentaram maior freqüência na placa subgengival (95.6% e 91.3%, respectivamente) do que na saliva (21.8% e 65.2, respectivamente) e sangue (17.4% e 60.86%, respectivamente) (p<0.0001 e p=0.004, respectivamente). T.forsythia e EBV-1 foram detectados com maior freqüência na placa subgengival (47.8%, 78.3%, respectivamente) e saliva (52.2%, 52.2%, respectivamente) do que no sangue (8.7% e 13%, respectivamente) (p=0.004 e p<0.005, respectivamente). A.actinomycetemcomitans e HSV-1foram detectados com freqüências similares nas três amostras nos dois grupos. Não houve associação entre coinfecção de herpes vírus e patógenos periodontais e doença periodontal em pacientes HIV+ com doença periodontal. Na saliva de pacientes HIV+ houve associação entre EBV-1, e coinfecção viral por EBV-1 e HCMV com a doença periodontal. / Herpesviruses are human pathogens widely distributed in the population and, recently, it has been studied a possible involvement of these viruses in the etiology of periodontal disease. HIV positive individuals (HIV+) have shown a higher prevalence of these viruses and the HIV-induced immunosuppression is known to facilitate the reactivation of these microorganisms. Thus, this study aimed to determine the presence of Herpes simplex virus type 1 (HSV-1), Cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1), relating to the presence of the periodontopathogens: Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis) and Tannerella forsythia (T. forsythia) in HIV+ individuals with periodontal disease. Samples were collected from subgingival plaque, saliva and capillary blood from twenty-seven HIV+ subjects with chronic periodontitis (HIV-p) and 23 HIV+ patients with gingivitis (HIV-g). The detection of bacterial species and herpesviruses were identified by Polymerase chain reaction (PCR) and nested PCR respectively. Statistical analysis showed that for HIV-p group, EBV-1 and T. forsythia presented higher detection in subgingival plaque (70.4% and 51.8%, respectively) and saliva (81.5%, 40.7%, respectively) than in blood (22%, 0, respectively) (p<0.005 e p<0.0001, respectively). P. gingivalis was more frequent in subgingival plaque (77.7%) than saliva (25.9%) and blood (25.9%) (p<0.0001). In the HIV-g, P. gingivalis and HCMV presented higher frequency in the subgingival plaque (95.6% and 91.3%, respectively) than in saliva (21.8% e 65.2, respectively) and blood (17.4% e 60.86%, respectively) (p<0.0001 e p=0.004). T.forsythia and EBV-1 were detected more frequently in the subgingival plaque (47.8%, 78.3%, respectively) and saliva (52.2%, 52.2%, respectively) than in blood (p=0.004 and p<0.005, respectively). A.actinomycetemcomitans and HSV-1 were detected with similar frequencies among the three samples in the two groups. There was no association between coinfection of herpesviruses and periodontal pathogens and periodontal disease in HIV patients with periodontal disease. In saliva of HIV patients there was no association between EBV-1, and viral coinfection by EBV-1and HCMV, with periodontal disease.

Apesar dos conhecimentos já existentes sobre o xilitol, seu efeito no desenvolvimento da cárie dentária ainda requer maiores esclarecimentos. Assim, este estudo in situ randomizado, duplo-cego e cruzado teve como objetivo determinar o efeito de xilitol em pastilhas na composição do biofilme dental e nos processos de desmineralização e remineralização do esmalte, comparado a um controle com pastilhas contendo sorbitol. Em duas fases de 14 dias, 11 voluntários utilizaram dispositivos palatinos com seis blocos de esmalte humano (três hígidos para avaliação da desmineralização + três previamente desmineralizados para avaliação da remineralização) com dureza de superfície conhecida. Sacarose 20% foi gotejada oito vezes ao dia apenas sobre os blocos hígidos. Cinco minutos após cada gotejamento, os dispositivos eram recolocados na boca e os voluntários chupavam pastilha com xilitol 88,3% ou sorbitol 84,5%. A utilização das pastilhas iniciou-se uma semana antes de cada fase experimental. Foi usado dentifrício sem flúor. Ao final de cada fase, o biofilme formado sobre os blocos foi coletado e dividido para análises microbiológica e bioquímica, e os fragmentos de esmalte foram analisados quanto a variação de dureza de superfície antes e após o experimento. A porcentagem de perda de dureza de superfície dos blocos de esmalte do grupo do xilitol apresentou uma tendência a ser menor do que aquela observada no grupo do sorbitol, embora a diferença não tenha sido significante (p= 0,066; ANOVA). Também não houve diferença estatisticamente significante entre os grupos em relação à porcentagem de ganho de dureza de superfície e à maioria dos parâmetros bioquímicos do biofilme. As médias das concentrações de fósforo inorgânico e de polissacarídeo intracelular no biofilme no experimento de desmineralização foram significantemente menores (p< 0,001 e p= 0,007) no grupo do sorbitol. As porcentagens de estreptococos do grupo mutans (SM) em relação ao total de estreptococos (S) (p= 0,037) no experimento de desmineralização, assim como as contagens de SM (p= 0,035) e lactobacilos (p= 0,048), e as porcentagens de SM em relação ao total de microrganismos (p= 0,035) e em relação a S (p= 0,017) no experimento de remineralização foram significantemente menores no biofilme do grupo do xilitol. Os demais parâmetros microbiológicos não foram influenciados de maneira significante pelos tratamentos. O uso de pastilhas com xilitol por curtos períodos de tempo não apresentou vantagem nem em diminuir a desmineralização nem em favorecer a remineralização do esmalte em comparação ao uso de pastilhas com sorbitol, mas alterou a ecologia bacteriana do biofilme, reduzindo as contagens e as porcentagens de importantes grupos de microrganismos cariogênicos. / In spite of the existing knowledge about xylitol, its effect on the development of dental caries is still a subject that requires further clarifications. Thus, this randomized, double-blind, crossover in situ study aimed at assessing the effect of xylitol mints in the dental biofilm composition and in the processes of enamel demineralization and remineralization, in comparison to a control group using sorbitol mints. During the two phases of 14 days, 11 volunteers wore palatal appliances with six human enamel blocks (three intact ones for evaluation of demineralization and three demineralized ones for the evaluation of remineralization) of known superficial hardness. A solution of 20% sucrose was dripped only on the intact enamel blocks eight times per day. Five minutes after each dripping, the appliances were placed back inside the mouth and the volunteers took either an 88.3% xylitol mint or an 84.5% sorbitol mint. Both types of mints started being used by the volunteers one week before each experimental phase. Non-fluoridated toothpaste was used. At the end of each phase, the biofilm formed over the blocks was collected and divided for microbiological and biochemical analysis and the enamel fragments were evaluated in relation to surface hardness variation before and after the experiment. The percentage of surface hardness loss of the enamel blocks in the xylitol group tended to be lower than in those of the sorbitol group although this difference was not significant (p= 0.066; ANOVA). Moreover, there were no statistically significant differences between the study groups regarding the percentage of surface hardness gain or regarding the biochemical parameters of the biofilm. The average concentrations of inorganic phosphorus and of intracellular polysaccharides in the biofilm for the demineralization experiment were significantly lower (p< 0.001 and p= 0.007) in the sorbitol group. The following results were significantly lower in the xylitol group biofilm: percentages of mutans streptococci (SM) in relation to the total number of streptococci (S) (p= 0.037) in the demineralization experiment; SM (p= 0.035) and lactobacilli (p= 0.048) count; and the percentages of SM in relation to the total number of microorganisms (p= 0.035) and in relation to S (p= 0.017) in the remineralization experiment. Other microbiological parameters were not significantly influenced by the treatments. Taking xylitol mints during short periods of time did not show advantages regarding the decrease of enamel demineralization or the promotion of enamel remineralization when compared to taking sorbitol mints. However, it did expressively alter the bacterial ecology of the biofilm, reducing the percentage and count of important groups of cariogenic microorganisms.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-04-26T13:32:51Z No. of bitstreams: 1 PDF - Thaíse Pereira Dantas Sampaio.pdf: 1018120 bytes, checksum: 4c51160c4e258fb5a00a596dc9c74100 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-22T20:32:37Z (GMT) No. of bitstreams: 1 PDF - Thaíse Pereira Dantas Sampaio.pdf: 1018120 bytes, checksum: 4c51160c4e258fb5a00a596dc9c74100 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-22T20:32:48Z (GMT) No. of bitstreams: 1 PDF - Thaíse Pereira Dantas Sampaio.pdf: 1018120 bytes, checksum: 4c51160c4e258fb5a00a596dc9c74100 (MD5) / Made available in DSpace on 2016-07-22T20:32:48Z (GMT). No. of bitstreams: 1 PDF - Thaíse Pereira Dantas Sampaio.pdf: 1018120 bytes, checksum: 4c51160c4e258fb5a00a596dc9c74100 (MD5) Previous issue date: 2014-05-28 / Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq / This study aimed to evaluate the in vitro antimicrobial activity of plant extracts and chemical fractions from Sideroxylon obtusifolium T.D. Penn on Streptococcus mutans (ATCC 27175), Streptococcus oralis (ATCC 10557), Streptococcus salivarius (ATCC 7073), Streptococcus parasanguinis (ATCC 903) and Candida albicans (ATCC 10231), as well as to identify the bioactive chemical substances contained in the extracts with the best antimicrobial activity. Lyophilized extracts of leaf and bark (LL and LB) and ethanol extracts of leaf and bark (EL and EB) of S. obtusifolium T. D. Penn were tested for their antimicrobial potential by determining their Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC). Tests were performed in triplicate by the microdilution method in three independent experiments. Phytochemical characterization was performed by measuring the content of total polyphenols, total flavonoids and condensed tannins. The EB extract of S. obtusifolium T. D. Penn showed bacteriostatic and bactericidal activity against Streptococcus mutans (MIC = 1000 µg/ml, MBC = 1000 µg/ml); the other streptococci strains were found to be resistant to the extract concentrations tested; all extracts (ethanol and lyophilized, from leaf and bark) showed inhibitory activity on Candida albicans (MIC = 500 µg/ml); the dichloromethane and n-butanol fractions of LL extract showed higher antifungal potential than the crude LL extract (MIC = 250 µg/ml; CFM = 500 µg/ml). Phytochemical characterization revealed predominance of polyphenol compounds (EB = 29.23%, LB = 25.98%), followed by condensed tannins (LB = 38.84%, LB = 17.78%). According to the results, it is suggested that Sideroxylon obtusifolium T. D. Penn has antifungal activity on C. albicans and antibacterial activity on S. mutans, possibly due to the presence of total polyphenols and condensed tannins. / O objetivo deste estudo foi avaliar a atividade antimicrobiana in vitro de extratos vegetais e frações mutans químicas de Sideroxylon obtusifolium T.D. Penn sobre Streptococcus mutans (ATCC de 27175), Streptococcus oralis (ATCC 10557), Streptococcus salivarius (ATCC 7073), Streptococcus parasanguinis (ATCC 903) e Candida albicans (ATCC 10231), bem como, identificar as classes de substâncias químicas bioativas presentes nos extratos de melhor atividade. Extratos liofilizados da folha e casca (LF e LC) e extratos etanólicos da folha e casca (EF e EC) de S. obtusifolium T. D. Penn foram submetidos à avaliação do potencial antimicrobiano através da Concentração Inibitória Mínima (CIM), Concentração Bactericida Mínima (CBM) e Concentração Fungicida Mínima (CFM). Os ensaios foram realizados pelo método da microdiluição em triplicata, em três experimentos independentes. A caracterização fitoquímica foi realizada através da quantificação do teor de polifenóis totais, flavonoides totais e taninos condensados. O extrato EC de S. obtusifolium T. D. Penn apresentou atividade bacteriostática e bactericida sobre Streptococcus mutans (CIM= 1000 µg/mL; CBM= 1000 µg/mL); as demais cepas de estreptococos mostraram-se resistentes às concentrações dos extratos testados; todos os extratos, etanólicos e liofilizados, da folha e casca apresentaram atividade inibitória sobre o crescimento de Candida albicans (CIM= 500 µg/mL); as frações diclorometano e n- butanol do extrato LF apresentaram potencial antifúngico maior que o extrato bruto LF (CIM= 250 µg/mL; CFM= 500 µg/mL). A caracterização fitoquímica revelou predomínio dos compostos polifenóis totais (EC= 29,23%; LC= 25,98%), seguidos por taninos condensados (LC= 38,84%; LF= 17,78%). De acordo com os resultados sugere-se que Sideroxylon obtusifolium TD Penn apresenta potencial antifúngico sobre C. albicans e potencial antibacteriano sobre S. mutans, podendo sua ação estar relacionada com a presença de compostos fitoquímicos da classe dos polifenóis totais e taninos condensados.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / As Mucopolissacaridoses (MPS) constituem um grupo de doenÃas raras, caracterizadas por deficiÃncias enzimÃticas que resultam em bloqueio na degradaÃÃo dos glicosaminoglicanos. O objetivo deste estudo foi avaliar a situaÃÃo periodontal de todos os pacientes com Mucopolissacaridose, atendidos no Hospital Infantil Albert Sabin e no Hospital Geral CÃsar Cals, FortalezaâCE. Foram avaliados 18 pacientes, por um cirurgiÃo-dentista previamente calibrado, que registrou os Ãndice de Pernus, Ãndice de Placa Bacteriana VisÃvel, Ãndice de Sangramento Gengival, PSR e Ãndice CPO-D/ceo-d. Em relaÃÃo ao volume gengival, observou-se que 72,2% dos pacientes apresentaram Ãndice de Pernus nos escores 1, 2 ou 3, que corresponde à presenÃa de hiperplasia gengival. Quando se avaliaram os cuidados com relaÃÃo à higiene oral dos pacientes, observou-se que quanto ao Ãndice de Sangramento Gengival 77,8% dos pacientes apresentaram Ãndice maior que 10%, 66,6% dos pacientes apresentaram Ãndice de Placa Bacteriana VisÃvel maior que 40%. Com relaÃÃo ao PSR 94,4% dos pacientes apresentou escore 1, correspondendo a sangramento, e 5,6% escore 2, correspondendo à presenÃa de cÃlculo alÃm de sangramento, e quanto ao CPO-D/ceo-d 61,1% apresentou Ãndice maior que 5. De uma maneira geral, observou-se que a situaÃÃo periodontal dos pacientes portadores de mucopolissacaridose à uma situaÃÃo que inspira maior cuidado, mostrando caracterÃsticas prevalentes como o aumento gengival, alÃm de altos Ãndices de Sangramento Gengival, Placa Bacteriana VisÃvel e CPO-D/ceo-d. / The Mucopolysaccharidosis (MPS) are a group of rare diseases characterized by enzyme deficiency that results in nondegradation of the glicosaminoglicans (GAGs). The aim of this study was to evaluate the periodontal status of all the patiente with MPS that are treated at the Hospital Infantil Albert Sabin and at the Hospital Geral CÃsar Cals, in Fortaleza, CearÃ, Brazil. A number of 18 patients were evaluated by a dentist that was previously calibrated, which registered the Pernus Index (IP), Visible Bacterium Plaque Index (IPB-V), Gingival Bleeding Index (ISG), PSR and Index that shows number of teeth that showed cavities, tooth loss or restoration (CPO-D/ceo-d). In relation to the gingival volume it was observed that 72,2% of the patients showed that the gingival was not in itÂs regular size. On the evaluation of dental hygiene, it was observed that 77,8% of the patients showed ISG greater than 10% and 66,6% of the patients showed IPB-V greater than 40%. In relation to PSR, 94,4% of the patients showed scored 1 which means gingival bleeding and 5,6% showed score 2 which means calculus besides gingival bleeding. And in relation to CPO-D/ceo-d 61,1% of the patients showed score greater than 5. In a general way it was observed that the periodontal status of the patients is a situation that requires more care, showing characteristics like gingival hyperplasias besides high scores of ISG, IPB-V and CPO-D/ceo-d.

Made available in DSpace on 2016-04-28T20:18:29Z (GMT). No. of bitstreams: 1 2008 - Samira Lessa Abdalla.pdf: 954479 bytes, checksum: ab7b6aa4f805848f97b44982e9c65f19 (MD5) Previous issue date: 2008-03-26 / The Periodontal Disease is caused by dental plaque accumulation on teeth and adjacent structures. Indices have been formulated for its measurement considering the amount and intensity of Dental Plaque and Calculus in the oral cavity through subjective visual evaluation. This study aims to evaluate the computerized analysis method for measurement of Dental Plaque and Calculus areas on the teeth of dogs in an experimental antimicrobial products evaluation model, by comparison with the visual evaluation in the oral cavity and also by the analysis of Dental Plaque and in several teeth. Sixteen beagles with similar characteristics and kept under the same management and diet were used and divided into Negative Control group (no treatment) and Positive Control group (chlorhexidine 0.12% sprayed in the oral cavity daily). Evaluations of oral cavity occurred before the periodontal treatment (performed under general inhalation anesthesia) and after seven days for Dental Plaque, and 28 for Calculus. The computerized Calculus area evaluation showed statistically significant difference in relation to the visual evaluation before and after periodontal treatment in the Negative Control group, as well as sensitivity in the chlorhexidine performance analysis (Positive Control group). It was observed through computerized evaluation that greater amounts of Dental Plaque and Calculus accumulate on the maxillary teeth than on the mandibular ones; the fourth maxillary pre-molar teeth were more affected than the third, first and second pre-molar ones followed by canine and then lateral incisor and that the fourth mandibular pre-molar teeth are more affected than third and second pre-molar ones followed by the first molar and canine. The area affected by Dental Plaque and Calculus on the lateral maxillary incisor teeth and on the four canines was below the range of 25% and its exclusion influenced significantly in the calculation of these parameters. It was concluded that the computerized evaluation is beneficial when compared to the visual one, requiring only one evaluator, and provides greater precision in the area measurement; and that teeth less affected by Dental Plaque and Calculus can sub-represent others more involved in the composition of oral cavity indices. / A Doen?a Periodontal ? causada pelo ac?mulo de Placa Bacteriana sobre os dentes e estruturas adjacentes. Para mensura??o desta doen?a t?m sido formulados ?ndices que consideram a quantidade e intensidade de Placa Bacteriana e C?lculo Dent?rio existentes na cavidade oral, por meio de avalia??o visual subjetiva. O presente estudo objetivou utilizar o m?todo de an?lise computadorizada, para medi??o de ?rea de Placa Bacteriana e C?lculo Dent?rio nos dentes de c?es em modelo experimental de avalia??o de produtos com a??o antimicrobiana, por meio da compara??o com avalia??o visual e tamb?m da an?lise da forma??o de Placa Bacteriana e C?lculo Dent?rio nos diversos dentes. Foram utilizados 16 c?es beagles com similares caracter?sticas e mantidos sob o mesmo manejo e dieta alimentar, divididos em grupos Controles, Negativo (sem tratamento) e Positivo (tratados com borrifa??o de clorexidina a 0,12%, na cavidade oral, uma vez ao dia). As avalia??es da cavidade oral ocorreram antes do tratamento periodontal, para Placa Bacteriana e C?lculo Dent?rio, que foi realizada sob anestesia geral inalat?ria, e ap?s sete dias para Placa Bacteriana, e 28 dias para C?lculo Dent?rio. A avalia??o computadorizada da ?rea de C?lculo Dent?rio mostrou diferen?a estatisticamente significante em rela??o ? avalia??o visual, antes e ap?s o tratamento periodontal, no grupo Controle Negativo, bem como sensibilidade na an?lise da atua??o da clorexidina (grupo Controle Positivo). Observou-se, por meio da avalia??o computadorizada, maior quantidade de ac?mulo de Placa Bacteriana e C?lculo Dent?rio nos dentes maxilares do que nos mandibulares; que os dentes maxilares 4? pr?-molares foram mais acometidos do que os 3?, 1? e 2? pr?-molares, seguidos pelos caninos e depois incisivos laterais, e que os dentes mandibulares 4? pr?-molares foram mais acometidos do que os 3? e 2? pr?-molares, seguidos pelos primeiros molares e depois caninos. A ?rea acometida por Placa Bacteriana e C?lculo Dent?rio nos dentes incisivos laterais maxilares e nos quatro caninos encontrou-se abaixo da faixa de 25% e sua exclus?o influenciou significantemente no c?lculo destes par?metros. Concluiu-se que a avalia??o computadorizada ? vantajosa em rela??o ? visual, por necessitar de somente um avaliador e conferir maior precis?o na medida da ?rea; e que os dentes menos acometidos por Placa Bacteriana e C?lculo Dent?rio podem sub-representar outros mais acometidos utilizados na composi??o de ?ndices da cavidade oral.

Apesar dos conhecimentos já existentes sobre o xilitol, seu efeito no desenvolvimento da cárie dentária ainda requer maiores esclarecimentos. Assim, este estudo in situ randomizado, duplo-cego e cruzado teve como objetivo determinar o efeito de xilitol em pastilhas na composição do biofilme dental e nos processos de desmineralização e remineralização do esmalte, comparado a um controle com pastilhas contendo sorbitol. Em duas fases de 14 dias, 11 voluntários utilizaram dispositivos palatinos com seis blocos de esmalte humano (três hígidos para avaliação da desmineralização + três previamente desmineralizados para avaliação da remineralização) com dureza de superfície conhecida. Sacarose 20% foi gotejada oito vezes ao dia apenas sobre os blocos hígidos. Cinco minutos após cada gotejamento, os dispositivos eram recolocados na boca e os voluntários chupavam pastilha com xilitol 88,3% ou sorbitol 84,5%. A utilização das pastilhas iniciou-se uma semana antes de cada fase experimental. Foi usado dentifrício sem flúor. Ao final de cada fase, o biofilme formado sobre os blocos foi coletado e dividido para análises microbiológica e bioquímica, e os fragmentos de esmalte foram analisados quanto a variação de dureza de superfície antes e após o experimento. A porcentagem de perda de dureza de superfície dos blocos de esmalte do grupo do xilitol apresentou uma tendência a ser menor do que aquela observada no grupo do sorbitol, embora a diferença não tenha sido significante (p= 0,066; ANOVA). Também não houve diferença estatisticamente significante entre os grupos em relação à porcentagem de ganho de dureza de superfície e à maioria dos parâmetros bioquímicos do biofilme. As médias das concentrações de fósforo inorgânico e de polissacarídeo intracelular no biofilme no experimento de desmineralização foram significantemente menores (p< 0,001 e p= 0,007) no grupo do sorbitol. As porcentagens de estreptococos do grupo mutans (SM) em relação ao total de estreptococos (S) (p= 0,037) no experimento de desmineralização, assim como as contagens de SM (p= 0,035) e lactobacilos (p= 0,048), e as porcentagens de SM em relação ao total de microrganismos (p= 0,035) e em relação a S (p= 0,017) no experimento de remineralização foram significantemente menores no biofilme do grupo do xilitol. Os demais parâmetros microbiológicos não foram influenciados de maneira significante pelos tratamentos. O uso de pastilhas com xilitol por curtos períodos de tempo não apresentou vantagem nem em diminuir a desmineralização nem em favorecer a remineralização do esmalte em comparação ao uso de pastilhas com sorbitol, mas alterou a ecologia bacteriana do biofilme, reduzindo as contagens e as porcentagens de importantes grupos de microrganismos cariogênicos. / In spite of the existing knowledge about xylitol, its effect on the development of dental caries is still a subject that requires further clarifications. Thus, this randomized, double-blind, crossover in situ study aimed at assessing the effect of xylitol mints in the dental biofilm composition and in the processes of enamel demineralization and remineralization, in comparison to a control group using sorbitol mints. During the two phases of 14 days, 11 volunteers wore palatal appliances with six human enamel blocks (three intact ones for evaluation of demineralization and three demineralized ones for the evaluation of remineralization) of known superficial hardness. A solution of 20% sucrose was dripped only on the intact enamel blocks eight times per day. Five minutes after each dripping, the appliances were placed back inside the mouth and the volunteers took either an 88.3% xylitol mint or an 84.5% sorbitol mint. Both types of mints started being used by the volunteers one week before each experimental phase. Non-fluoridated toothpaste was used. At the end of each phase, the biofilm formed over the blocks was collected and divided for microbiological and biochemical analysis and the enamel fragments were evaluated in relation to surface hardness variation before and after the experiment. The percentage of surface hardness loss of the enamel blocks in the xylitol group tended to be lower than in those of the sorbitol group although this difference was not significant (p= 0.066; ANOVA). Moreover, there were no statistically significant differences between the study groups regarding the percentage of surface hardness gain or regarding the biochemical parameters of the biofilm. The average concentrations of inorganic phosphorus and of intracellular polysaccharides in the biofilm for the demineralization experiment were significantly lower (p< 0.001 and p= 0.007) in the sorbitol group. The following results were significantly lower in the xylitol group biofilm: percentages of mutans streptococci (SM) in relation to the total number of streptococci (S) (p= 0.037) in the demineralization experiment; SM (p= 0.035) and lactobacilli (p= 0.048) count; and the percentages of SM in relation to the total number of microorganisms (p= 0.035) and in relation to S (p= 0.017) in the remineralization experiment. Other microbiological parameters were not significantly influenced by the treatments. Taking xylitol mints during short periods of time did not show advantages regarding the decrease of enamel demineralization or the promotion of enamel remineralization when compared to taking sorbitol mints. However, it did expressively alter the bacterial ecology of the biofilm, reducing the percentage and count of important groups of cariogenic microorganisms.

Master of Science in Dentistry / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Includes bibliographical references (leaves 127-141)

Streptococcus gordonii is a primary coloniser of the tooth surface where it efficiently ferments carbohydrates at pH levels above 6.0. By not being able to maintain the pH of dental plaque to a level required for enamel dissolution, the dominance of S. gordonii in dental plaque is considered a sign of a healthy oral cavity. However, upon entering the bloodstream and encountering a rise in pH, S. gordonii may become pathogenic, being one of the major causative organisms associated with infective endocarditis. Proteome analyses of S. gordonii grown at steady state in a chemostat allowed the phenotypic changes associated with alterations in pH levels characteristic of these two environments to be determined. As an initial starting point to this study, a two-dimensional electrophoresis (2- DE) reference map of S. gordonii grown at pH 7.0 was produced. Although only 50% of the S gordonii genome was available in an annotated form during the course of this study, the closely related Streptococcus pneumoniae genome (with which S. gordonii shares 97.24% DNA sequence homology) had been completed in 2001. The use of both of these databases allowed many of the S. gordonii proteins to be identified by mass spectrometry. Four hundred and seventy six protein spots, corresponding to 250 different proteins, or 12.5% of the S. gordonii proteome, were identified, giving rise to the first comprehensive proteome reference map of this oral bacterium. Of the 250 different proteins, 196 were of cellular origin while 68 were identified from the extracellular milieu. Only 14 proteins were common to both compartments. Of particular interest among the 54 uniquely identified extracellular proteins was a homologue of a peptidoglycan hydrolase that has been associated with virulence in S. pneumoniae. Among the other proteins identified were ones involved in transport and binding, energy metabolism, translation, transformation, stress response and virulence. Twelve cell envelope proteins were identified as well as 25 others that were predicted to have a membrane association based on the presence of at least one transmembrane domain. The study also confirmed the existence of 38 proteins previously designated as �hypothetical� or with no known function. Mass spectral data for over 1000 protein spots were accumulated and archived for future analysis when sequencing of the S. gordonii genome is finally completed. Following the mapping of the proteome of S. gordonii, alterations in protein spots associated with growth of the bacterium at pH intervals of 0.5 units in the pH range 5.5 - 7.5 were determined. Only 16 protein spots were shown to be significantly altered in their level of expression despite the range of pH studied. Among the differentially expressed proteins was a manganese-dependent inorganic pyrophosphatase (PpaC), which regulates expression of adhesins required for coaggregation. The expression of PpaC was highest at pH 6.5 - 7.0, the pH of a healthy oral cavity, indicating that PpaC may play an important part in dental plaque formation. Another differentially expressed protein was the heat-inducible transcription repressor (HrcA). Alterations in HrcA were consistent with its role as a negative repressor in regulating heat-shock proteins at low pH, even though no changes in the level of heat-shock proteins were observed as the pH declined. This result gave rise to the hypothesis that the possible reason cariogenic bacteria, such as Streptococcus mutans, can out compete S. gordonii at low pH might simply be due to their ability to manipulate their proteome in a complex manner for survival and persistence at low pH, unlike S. gordonii. This may imply some prevailing level of genetic regulation that is missing in S. gordonii.