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Extensão, gravidade e fatores associados à hipersensibilidade dentinária : estudo transversal / Extent, severity and factors associated with dentin hypersensitivity : a cross-sectional studySilveira, Carina Folgearini January 2016 (has links)
A hipersensibilidade dentinária (HD) é descrita na literatura como uma dor aguda, de curta duração, provocada por estímulos térmico, tátil, osmótico, químico ou evaporativo em região de exposição dentinária, não sendo atribuída à dor causada pela presença de defeito ou doença de origem dentária. Esse tipo de acometimento tem sido cada vez mais reportado pelos pacientes, em vista disso, o objetivo desse estudo foi avaliar a extensão e gravidade de HD, bem como sua associação com indicadores periodontais [índice de placa (IP), índice gengival (IG) e recessão gengival (RG)] em uma amostra composta por 132 indivíduos com HD diagnosticada por meio de estímulo térmico/evaporativo (jato de ar) associada à escala Schiff. Análises descritivas foram feitas e as porcentagens médias de IP e IG foram estimadas considerando 6 sítios por dente e também 3 sítios das faces vestibulares. Além disso, os dados foram analisados através de modelos uni e multivariados utilizando análises de regressão linear. A média de idade foi de 30.66±10.33, sendo o sexo feminino mais afetado pela HD (83.3%). Foi possível observar que a HD esteve associada à recessão gengival. A prevalência de dentes com recessão gengival foi de 17.17%, enquanto que a prevalência de recessão em dentes com HD foi de 77.1% e a média de recessão vestibular foi de 1.58±0.87. Quando considerada a média de dentes com 1 ou mais milímetros de recessão, observou-se que, em média, 4.48 dos dentes apresentaram esta condição. Um maior número médio de dentes com recessão e menores escores médios de IP nos sítios vestibulares apresentaram-se signicativamente associados ao número médio de dentes com HD. A gravidade da HD nos pacientes foi significativamente influenciada por maior média de recessão gengival e foi maior nos pacientes do sexo feminino. Dentes que possuíam maiores médias de recessão e maiores escores médios de IP e menores de IG nos sítios vestibulares apresentaram maiores valores na escala Schiff (p<0.05). Frente aos achados, é possível observar que portadores de HD têm um grande número de dentes afetados por esta condição e que estes apresentam recessão. Além disto, nos dentes que apresentam HD, a gravidade desta está associada a presença de mais placa e melhor condição gengival, além da extensão da recessão. / Dentin hypersensitivity (DH) is described in the literature as an acute short-term pain caused by thermal, tactile, osmotic, chemical or evaporative stimuli in the region of dentin exposure and not attributed to pain caused by the presence of defect or disease of dental origin. Therefore, the aim of this study was to evaluate the extent and severity of DH, as well as its correlation with periodontal indicators [plaque index (PI), gingival index (GI) and gingival recession (GR)] in 132 individuals with DH diagnosed by thermal/evaporative (air blast) stimulation associated with the Schiff scale. Descriptive analyzes were made and the mean percentages of PI and GI were estimated considering 6 sites per tooth and also 3 buccal sites. In addition, the data were analyzed using univariate and multivariate models using linear regression analysis. The mean age was 30.66 ± 10.33, female sex being more affected by DH (83.3%). It was possible to observe that DH was associated to gingival recession. The prevalence of teeth with gingival recession was 17.17%, while the prevalence of recession in teeth with DH was 77.1%. The mean of vestibular recession was 1.58 ± 0.87, and when considered the mean teeth with 1 or more millimeters recession, it was observed that, a mean of 4.48 teeth presented this condition. A higher mean number of teeth with recession and lower mean PI scores in the vestibular sites were associated (p<0.001) with the mean number of teeth with DH. The severity of DH in number of patients was significantly influenced by the higher mean of gingival recession and was higher in the female patients. Teeth that had higher recession mean and higher mean PI scores at the buccal sites, but lower GI scores at this sites, presented significantly higher values on the Schiff scale (p <0.05). In view of the findings, it is possible to observe that DH patients have a large number of teeth affected by this condition and that these present gingival recession. In addition, in the teeth that present DH, the severity is associated with the presence of more plaque and better gingival condition, in addition to the extent of the recession.
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Desenvolvimento e caracterização de uma resina adesiva experimental acrescida de hidroxietil acrilamida / Development and characterization of an experimental adhesive with the addition of hydroxyethil acrylamideRodrigues, Stefani Becker January 2013 (has links)
O objetivo do presente estudo foi desenvolver e caracterizar resinas adesivas contendo hidroxietil acrilamida (HEAA). Três grupos de resinas adesivas foram formulados, GHEAA33% (33,3% de HEAA + 66,6% de bisfenol A glicedil dimetacrilato - BisGMA), GHEAA50% (50% de HEAA + 50% de BisGMA) e GHEMA (33,3% de hidroxietil metacrilato - HEMA + 66,6% de BisGMA). Parâmetros como resistência à flexão (n= 12), grau de inchamento (n= 3), temperatura de transição vítrea (n= 3) e degradação em solvente (n= 5) foram avaliados de cada resina adesiva. Em adição foi avaliado com calorimetria exploratória diferencial (DSC), o processo de polimerização das resinas experimentais (n= 3), bem como dos homopolímeros componentes, BisGMA, HEMA, HEAA, HEMA* sem adição de etil 4- dimetilaminobenzoato (EDAB) e HEAA* sem adição de EDAB. Os resultados foram analisados estatisticamente com auxílio de ANOVA de uma via, teste de Tukey e teste t pareado. Todas as resinas adesivas e homopolímeros, exceto HEMA, HEAA* e HEMA*, apresentaram uma alta taxa de polimerização e um alto grau de conversão. Não houve diferença estatística entre as resinas adesivas para a temperatura de transição vítrea e a degradação em solvente (p>0,05). Entretanto, o grupo GHEAA33% apresentou a menor variação de grau de inchamento (p<0,05) e os menores valores de resistência à flexão (p<0,05) quando comparado com o grupo GHEMA. Considerando que a hidroxietil acrilamida foi capaz de promover o aumento do processo de polimerização de resinas adesivas experimentais e, tendo em vista sua potencial resistência à degradação hidrolítica e ainda, com base nos resultados dos demais ensaios, o grupo GHEAA33%, parece reunir as melhores condições de desenvolvimento de resinas adesivas inovadoras. / The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three groups of experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Parameters such as flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. In addition, the polymerization process of each adhesive resin group (n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB, were also evaluated using differential scanning calorimetry (DSC). The results were analyzed using one way ANOVA, Tukey’s test, and Student’s t-test. For all of the resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA* homopolymer, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the glass transition temperature and for softening in solvent for the adhesive resins assayed. In contrast, the GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. HEAA was also found to promote the polymerization process and was resistant to hydrolytic degradation. Thus, GHEAA33% appears to be a promising alternative for the production of innovative adhesive resins.
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Epidemiologia da hipersensibilidade dentinária / Epidemiology of dentin hypersensitivityCosta, Ricardo dos Santos Araujo January 2013 (has links)
Hipersensibilidade dentinária (HSD) é caracterizada como uma dor dentária curta e aguda, causada em resposta a estímulos térmicos, evaporativos, táteis ou osmóticos, e que não pode ser atribuída a qualquer outro tipo de patologia. A epidemiologia da HSD ainda é pouco estuda em nível populacional. O objetivo desta dissertação foi abordar a epidemiologia da HSD através da revisão crítica da literatura e da apresentação de um estudo de base populacional sobre prevalência, extensão e indicadores de risco para essa condição.Uma amostra representativa de 1023 habitantes adultos, com mais de 35 anos de idade, residentes em Porto Alegre foi obtida através de uma amostragem probabilística proporcional estratificada de múltiplo-estágio. Os participantes do estudo responderam a um questionário estruturado a respeito de dados sociodemográficos e comportamentais e receberam um exame clínico para diagnóstico de HSD térmico (jato de ar) e tátil (sonda) aplicados na superfície vestibular de todos os dentes presentes. Comandos analíticos que consideram a amostra complexa foram utilizados para gerar estimativas em modelos de risco multivariados. Aproximadamente um terço da população foi diagnosticada com HSD (jato de ar = 33,4% / sonda = 34,2%). Dentre os indivíduos que apresentaram HSD, em média 2 a 3 dentes apresentaram HSD. Os dentes mais afetados com HSD foram pré-molares superiores, molares superiores e pré-molares inferiores. Recessão gengival foi fator determinante para a ocorrência de HSD e foi modelada separadamente das demais variáveis. Mulheres, indivíduos mais jovens, fumantes, de melhor nível educacional e aqueles que relatam tratamento periodontal tiveram significativamente mais chance de HSD. Conclui-se que a prevalência e de HSD encontrada na população estudada é alta, porém com um número pequeno de dentes afetados. A ocorrência de HSD está associada a fatores comportamentais e sociodemográficos importantes, para os quais se podem estabelecer estratégias preventivas em nível individual e populacional. / Dentine hypersensitivity (DH) is characterized by an acute and short dental pain in response to thermal, evaporative, tactile and osmotic stimuli, which cannot be attributed to any other type of pathology. The epidemiology of DH is still little studied on the population level. The aim of this thesis was to assess the epidemiology of DH by conducting a critical appraisal of the literature and presenting the findings of a population-based study about the prevalence, extent and risk indicators of this condition. A representative sample of 1,023 adult 35 years and older inhabitants of Porto Alegre was obtained using a multistage, stratified, proportional to size, probability sampling strategy. Participants answered a structured questionnaire about sociodemographic and behavioral variables and were submitted to a clinical examination to diagnose DH using a blast of air and a manual probe on the buccal surfaceof all present teeth. Analytical commands that take into consideration the complex sampling design were used to generate estimates and multivariable risk models. Approximately one third of the population was diagnosed with DH (air blast= 33.4% and probe= 34.2%). Among individuals with DH, in average 2 to 3 teeth were affected by DH. The teeth most affected by DH were maxillary premolars and molars, followed by mandibular premolars. Gingival recession was a determinant factor for the occurrence of DH and was modeled separately from the other variables. Females, younger individuals, smokers, individuals of higher education and those reporting positive history of periodontal treatment had significantly higher chances of DH. It can be concluded that the prevalence of DH found in the studied population is high, although with few teeth affected. The occurrence of DH is associated with important sociodemographic and behavioral factors for which preventive strategies may be established on individual and population levels.
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Desenvolvimento e caracterização de uma resina adesiva experimental acrescida de hidroxietil acrilamida / Development and characterization of an experimental adhesive with the addition of hydroxyethil acrylamideRodrigues, Stefani Becker January 2013 (has links)
O objetivo do presente estudo foi desenvolver e caracterizar resinas adesivas contendo hidroxietil acrilamida (HEAA). Três grupos de resinas adesivas foram formulados, GHEAA33% (33,3% de HEAA + 66,6% de bisfenol A glicedil dimetacrilato - BisGMA), GHEAA50% (50% de HEAA + 50% de BisGMA) e GHEMA (33,3% de hidroxietil metacrilato - HEMA + 66,6% de BisGMA). Parâmetros como resistência à flexão (n= 12), grau de inchamento (n= 3), temperatura de transição vítrea (n= 3) e degradação em solvente (n= 5) foram avaliados de cada resina adesiva. Em adição foi avaliado com calorimetria exploratória diferencial (DSC), o processo de polimerização das resinas experimentais (n= 3), bem como dos homopolímeros componentes, BisGMA, HEMA, HEAA, HEMA* sem adição de etil 4- dimetilaminobenzoato (EDAB) e HEAA* sem adição de EDAB. Os resultados foram analisados estatisticamente com auxílio de ANOVA de uma via, teste de Tukey e teste t pareado. Todas as resinas adesivas e homopolímeros, exceto HEMA, HEAA* e HEMA*, apresentaram uma alta taxa de polimerização e um alto grau de conversão. Não houve diferença estatística entre as resinas adesivas para a temperatura de transição vítrea e a degradação em solvente (p>0,05). Entretanto, o grupo GHEAA33% apresentou a menor variação de grau de inchamento (p<0,05) e os menores valores de resistência à flexão (p<0,05) quando comparado com o grupo GHEMA. Considerando que a hidroxietil acrilamida foi capaz de promover o aumento do processo de polimerização de resinas adesivas experimentais e, tendo em vista sua potencial resistência à degradação hidrolítica e ainda, com base nos resultados dos demais ensaios, o grupo GHEAA33%, parece reunir as melhores condições de desenvolvimento de resinas adesivas inovadoras. / The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three groups of experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Parameters such as flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. In addition, the polymerization process of each adhesive resin group (n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB, were also evaluated using differential scanning calorimetry (DSC). The results were analyzed using one way ANOVA, Tukey’s test, and Student’s t-test. For all of the resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA* homopolymer, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the glass transition temperature and for softening in solvent for the adhesive resins assayed. In contrast, the GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. HEAA was also found to promote the polymerization process and was resistant to hydrolytic degradation. Thus, GHEAA33% appears to be a promising alternative for the production of innovative adhesive resins.
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Epidemiologia da hipersensibilidade dentinária / Epidemiology of dentin hypersensitivityCosta, Ricardo dos Santos Araujo January 2013 (has links)
Hipersensibilidade dentinária (HSD) é caracterizada como uma dor dentária curta e aguda, causada em resposta a estímulos térmicos, evaporativos, táteis ou osmóticos, e que não pode ser atribuída a qualquer outro tipo de patologia. A epidemiologia da HSD ainda é pouco estuda em nível populacional. O objetivo desta dissertação foi abordar a epidemiologia da HSD através da revisão crítica da literatura e da apresentação de um estudo de base populacional sobre prevalência, extensão e indicadores de risco para essa condição.Uma amostra representativa de 1023 habitantes adultos, com mais de 35 anos de idade, residentes em Porto Alegre foi obtida através de uma amostragem probabilística proporcional estratificada de múltiplo-estágio. Os participantes do estudo responderam a um questionário estruturado a respeito de dados sociodemográficos e comportamentais e receberam um exame clínico para diagnóstico de HSD térmico (jato de ar) e tátil (sonda) aplicados na superfície vestibular de todos os dentes presentes. Comandos analíticos que consideram a amostra complexa foram utilizados para gerar estimativas em modelos de risco multivariados. Aproximadamente um terço da população foi diagnosticada com HSD (jato de ar = 33,4% / sonda = 34,2%). Dentre os indivíduos que apresentaram HSD, em média 2 a 3 dentes apresentaram HSD. Os dentes mais afetados com HSD foram pré-molares superiores, molares superiores e pré-molares inferiores. Recessão gengival foi fator determinante para a ocorrência de HSD e foi modelada separadamente das demais variáveis. Mulheres, indivíduos mais jovens, fumantes, de melhor nível educacional e aqueles que relatam tratamento periodontal tiveram significativamente mais chance de HSD. Conclui-se que a prevalência e de HSD encontrada na população estudada é alta, porém com um número pequeno de dentes afetados. A ocorrência de HSD está associada a fatores comportamentais e sociodemográficos importantes, para os quais se podem estabelecer estratégias preventivas em nível individual e populacional. / Dentine hypersensitivity (DH) is characterized by an acute and short dental pain in response to thermal, evaporative, tactile and osmotic stimuli, which cannot be attributed to any other type of pathology. The epidemiology of DH is still little studied on the population level. The aim of this thesis was to assess the epidemiology of DH by conducting a critical appraisal of the literature and presenting the findings of a population-based study about the prevalence, extent and risk indicators of this condition. A representative sample of 1,023 adult 35 years and older inhabitants of Porto Alegre was obtained using a multistage, stratified, proportional to size, probability sampling strategy. Participants answered a structured questionnaire about sociodemographic and behavioral variables and were submitted to a clinical examination to diagnose DH using a blast of air and a manual probe on the buccal surfaceof all present teeth. Analytical commands that take into consideration the complex sampling design were used to generate estimates and multivariable risk models. Approximately one third of the population was diagnosed with DH (air blast= 33.4% and probe= 34.2%). Among individuals with DH, in average 2 to 3 teeth were affected by DH. The teeth most affected by DH were maxillary premolars and molars, followed by mandibular premolars. Gingival recession was a determinant factor for the occurrence of DH and was modeled separately from the other variables. Females, younger individuals, smokers, individuals of higher education and those reporting positive history of periodontal treatment had significantly higher chances of DH. It can be concluded that the prevalence of DH found in the studied population is high, although with few teeth affected. The occurrence of DH is associated with important sociodemographic and behavioral factors for which preventive strategies may be established on individual and population levels.
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Estabilidade da interface de uniÃo de sistemas adesivos convencionais aplicados à dentina saturada com alcoÃis / Stability of interface created by simplified etch-and-rinse adhesives to alcohol-saturated acid-etched dentinLÃvia de Oliveira Barros 17 February 2011 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Existe um consenso de que a instabilidade da interface de uniÃo resina-dentina està relacionada com a quantidade de monÃmeros hidrofÃlicos presentes no sistema adesivo. Dessa forma, interfaces adesivas mais duradouras seriam alcanÃadas com a utilizaÃÃo de sistemas adesivos mais hidrofÃbicos. Uma maneira de unir monÃmeros hidrÃfobos à dentina à atravÃs da saturaÃÃo da matriz dentinÃria desmineralizada por etanol ao invÃs de Ãgua (ethanol-wet bonding technique). O objetivo deste trabalho in vitro foi avaliar o efeito do protocolo de saturaÃÃo dentinÃria, utilizando alcoÃis, na estabilidade da interface de uniÃo produzida por sistemas adesivos convencionais de dois passos. Para isso, foram utilizados 20 terceiros molares humanos, que tiveram a dentina coronÃria exposta e foram distribuÃdos aleatoriamente em quatro grupos experimentais (n=5): Adper Single Bond 2 (SB) aplicado sobre dentina saturada com Ãgua ou etanol; e XP Bond (XP) aplicado sobre dentina saturada com Ãgua ou tert-butanol. O protocolo de saturaÃÃo da dentina foi realizado atravÃs da aplicaÃÃo de 2 μl de etanol 100% ou tert-butanol 99,5% diretamente sobre a dentina por um perÃodo de 60 s. Um platà de resina composta foi confeccionado sobre superfÃcie dentinÃria apÃs a aplicaÃÃo do sistema adesivo e os espÃcimes foram cortados pela tÃcnica non-trimming de obtenÃÃo de palitos para o teste de microtraÃÃo. Os palitos de cada dente foram igualmente divididos em dois subgrupos: imediatamente testado ou envelhecido em soluÃÃo de NaOCl a 10% por 1 hora. Os espÃcimes foram tracionados atà a ruptura da uniÃo a uma velocidade de 1 mm/min e sua forÃa de uniÃo mensurada. Os palitos fraturados foram analisados e classificados de acordo com o modo de fratura em mista, adesiva, coesiva em dentina e coesiva em compÃsito, e os valores expressos em porcentagem. Os valores de resistÃncia de uniÃo foram estatisticamente analisados usando os testes ANOVA a trÃs critÃrios e Tukey (α=0.05). Discos extras de dentina foram submetidos aos procedimentos adesivos de cada grupo testado e utilizados para investigar as caracterÃsticas morfolÃgicas da interface de uniÃo atravÃs de microscopia Ãptica apÃs imersÃo em soluÃÃo amonical de nitrato de prata. Os resultados do teste de microtraÃÃo mostraram que a imersÃo em soluÃÃo de NaOCl reduziu significativamente a forÃa de uniÃo em comparaÃÃo aos grupos controle (p<0.05) e aumentou a nanoinfiltraÃÃo das interfaces adesivas de todos os sistemas adesivos testados. A saturaÃÃo da dentina com etanol 100% reduziu os valores de resistÃncia adesiva para SB quando comparado ao grupo controle, e esta mesma tendÃncia foi observada na infiltraÃÃo de prata. O uso do tert-butanol 99,5% nÃo afetou os valores de resistÃncia adesiva para o XP, assim como a deposiÃÃo de nitrato de prata na interface adesiva.
ConclusÃo: Os protocolos simplificados de saturaÃÃo da dentina com alcoÃis utilizados no presente estudo nÃo foram capazes de melhorar a estabilidade da interface de uniÃo para sistemas adesivos convencionais de dois passos. / There is a consensus that the resin-dentin bond instability is correlated with increased hydrophilic resin monomer content in dentin adhesive. Thus, more durable bonds could be created when more hydrophobic resins were used. One way to bond hydrophobic monomers to acid-etched dentin is saturating the demineralized dentin with ethanol instead of water (ethanol-wet bonding technique). The objective of this in vitro study was to evaluate the effect of âalcohol wet bondingâ technique on the stability of adhesive interface produced by two-step etch-and-rinse adhesives systems. For this, it was used 20 human third molars that had superficial dentin exposed and were randomly divided into four experimental groups (n=5): Adper Single Bond 2 (SB) bonded to acid-etched dentin saturated with water or ethanol; and XP Bond (XP) bonded acid-etched dentin saturated with water or 99.5% tert-butanol. The simplified dentin dehydration protocol was performed using 2 μl 100% ethanol or 99.5% tert-butanol directly applied in dentin for 60 s. Composite build-ups were built on dentin surface and specimens were cut into non-trimming dentin-composite beams to microtensile testing. Beams from each tooth were divided equally in two subgroups: immediately tested and aged by immersion in 10% NaOCl solution for 1 h. Specimens were pulled until failure at crosshead speed of 1 mm/min and bond strength was calculated. Fractured sticks were analyzed and classified according to the failure mode as mixed, adhesive, cohesive in dentin and cohesive in composite; and expressed in percentage. Data from μTBS test were statistically analyzed using three-way ANOVA and Tukey tests (α=0.05). Additional dentin disks were bonded using the same groups tested and the morphological characteristics of adhesive interface were investigated by light microscopy after immersion in ammoniacal silver nitrate solution. μTBS results showed that NaOCl solution reduced significantly bond strength comparing with the control groups (p<0.05) and increased the silver nitrate interfacial deposit for all adhesives tested. SB used in ethanol saturated-dentin showed significant lower bond strength values in comparison with SB control group, and this same tendency was observed in the silver nitrate deposition. The use of tert-butanol did not influence XP bond strengths values and silver nitrate deposits.
Conclusion: The âalcohol wet bondingâ simplified technique used in the present study was not able to improve resin-dentin bond stability for simplified etch-and-rinse adhesive systems.
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Exploring the physiological variables of oxygen isotope composition in chondrychthyan teethOliveira, Carlos January 2019 (has links)
Since the discoveries of vertebrate bioapatite’s ability to record oxygen isotopecomposition of ambient seawater were made (Kolodny, 1983), oxygen isotopes have beenwidely used as a climatic and oceanographic proxy. The δ18OP aquatic vertebrate apatite isa function of the δ18Ow value of the ambient water, yet “vital effects” on the δ18OP compositionhave been reported previously (Venneman et al., 2013). I have analysed δ18O compositionin the teeth of six extant shark and ray (chondrichthyan) species from the tropical ocean tankof the Blackpool Sea Life Center, UK. The teeth were naturally shed and collected from thetank substrate.Preparation of samples was performed in the Laboratory of Isotope Geology at the NaturalHistory Museum of Stockholm (Sweden), and the δ18O was measured at the NordSIM facility,using secondary ionization mass spectrometry (SIMS) by a high precision and high spatialresolutionCAMECA IMS 1280 ion microprobe.Data treatment was followed by statistical analysis. Results show significant δ18O differencesat inter-tissue level. I could also illustrate the impact of organics-pretreatment on the finalδ18O values, with the outcome of one more favourable pretreatment for SIMS analysis. Intertaxonvariability was observed, without much statistical confidence, but I hypothesize that itmay be due to the difference in tissue crystallization and organic quantity between species.
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Breastfeeding, Weaning Practices, and Childhood Diet in Rural Roman Italy / A Stable Isotope Investigation of Early Life Diet from Rural Roman Italy Using Incremental DentineBorisov, Katarina January 2023 (has links)
This thesis examines breastfeeding, weaning, and the post-weaning diets of 18 adults (18y+) and two subadults (aged 10y – 14y) from the rural Imperial Roman (1st – 4th c. CE) site of Vagnari, located in southern Italy. The investigation used a new method to sample dentine sections that accounts for the oblique nature of dentine development and allowed for the assignment of age categories to diagenetically altered teeth without visible dentine lines. The results indicate Vagnari children were weaned by ~3.5y, and that some males appear to have been breastfed longer than females. Despite the similar ages-at-weaning across the sample, the individuals in this study demonstrated a variety of weaning rates (i.e., speeds or paces), post-weaning dietary trends, and changes in diet across the life course. Some individuals (n = 6) appear to have been weaned rapidly, marked by significant removal of breastmilk prior to 2.5y, with small amounts of breast milk remaining in the diet until ~3.5y. Other children (n = 9) were weaned gradually, with slow, consistent removal of breastmilk until as late as 5.0y. Throughout and after the weaning period, children were fed a diet based on C3 plants and terrestrial proteins such as wheat, goat/sheep, and their by-products. A comparison of early life dentine and adult bone collagen signals for 14 individuals revealed changes in diet with increasing age, in which most people had increased access to higher terrestrial food sources such as pork and/or small amounts of marine food later in life. However, there was notable variation in dietary trends and practices across the sample, suggesting diverse dietary patterns among people from Vagnari. / Thesis / Master of Arts (MA) / In this thesis, I used samples from tooth dentine to analyze longitudinal stable isotope data for breastfeeding, weaning, and post-weaning dietary signals in a sample of 20 individuals from the Roman Imperial estate of Vagnari (1st – 4th c. CE) located in southern Italy. On average, children were weaned by ~3.5 years of age. Despite the similar age-at-weaning across the sample, individuals exhibited different weaning patterns and diversity in early life dietary practices at Vagnari. During and after weaning, the isotope data indicate that children were fed with C3 plants (e.g., wheat) and terrestrial proteins such as sheep/goat and pig. I analyzed childhood and adult diet by comparing dentine stable isotope data to bone collagen results from a sub-sample of 14 individuals. There was variability between the childhood dentine data and the adult bone collagen data, where individuals appeared to eat more pork and small amounts of fish later in life. This is the first study to explore breastfeeding and weaning practices of rural Roman children in southern Italy using stable isotope analysis of tooth dentine.
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Reproductive life histories: can incremental dentine isotope analysis identify pubertal growth, pregnancy and lactation?Feuillâtre, C., Beaumont, Julia, Elamin, F. 16 May 2022 (has links)
Yes / There are few reliable osteological indicators to detect parity or infer puberty in skeletal remains. Nitrogen (δ15N) and stable carbon (δ13C) isotope ratios in human tissues can be affected by metabolically unbalanced states engendered by pregnancy or rapid growth, offering potential biomarkers.
This pilot study explores the potential of incremental dentine-collagen isotope ratio analysis to identify puberty and gestation.
Methodology: Incremental dentine δ15N and δ13C profiles were produced by analysing third molars extracted as part of dental treatment of 10 individuals living in Sudan. Demographic and anthropometric data at the time of tooth extraction was available. Medical histories were unknown.
Results: Isotopic signatures potentially related to pubertal growth, with an average δ15N reduction of 0.78±0.29‰, are indicated. Six isotopic signals suggestive of pregnancy, with an average δ15N decrease of 0.48±0.22‰, are also observed. The timing, speed and amplitude of post-partum δ15N patterns seemingly infer infant feeding practices and maternal nutritional status.
Conclusion: This pilot study highlights the potential of incremental dentine isotope analysis for the reconstruction of early reproductive histories in skeletal remains. However, controlled studies with larger human cohort are needed to validate these findings, establish isotopic signals linked to puberty and lactation, and improve chronology accuracy.
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Auditory ossicles: a potential biomarker for maternal and infant health in uteroLeskovar, T., Beaumont, Julia, Lisic, N., McGalliard, S. 23 August 2019 (has links)
Yes / Background: Carbon (δ13C) and nitrogen (δ15N) isotope ratios of collagen from teeth and bone are used to study human nutrition and health. As bones are constantly remodelling throughout life, isotopic values of bone collagen represent an average of several years. In contrast, human teeth do not remodel and their primary dentine contains only the isotopic data from the time of formation. In contrast to all other bones, human auditory ossicles also appear not to remodel. As they develop in utero and finish formation in the first 2 years of life, their collagen should also represent isotopic values of these two relatively short periods.
Aim: By comparing δ13C and δ15N data from ossicles and incremental dentine, this study aims to investigate how two developmental periods of the ossicles, in utero and the first 2 years of life, reflect in collagen obtained from the ossicles.
Subject and methods: Ossicle and tooth samples of 12 individuals aged 0.5 ± 0.4 years to 13 ± 1 years from the nineteenth century St. Peter’s burial ground in Blackburn were collected and processed to obtain bulk bone and incremental dentine collagen which was measured for δ13C and δ15N.
Results: Averaged δ13C and δ15N of ossicles are lower when compared to every age group except after 3 years of age. Average offset between ossicles and dentine of different groups ranges from 0.4–0.9‰ for δ13C and from 0.3–0.9‰ for δ15N, with highest counterbalance at birth and after the first 5 months after birth.
Conclusions: There appears to be a systematic offset between the dentine and ossicle data. It seems that the second phase of development does not influence the isotopic values of collagen significantly and the data we are obtaining from ossicles represents the in utero period. / Research grant from The Society for the Study of Human Biology.
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