Volcanic activity, and the resultant deposits and structures at the Earth's surface, are the outcome of the inner workings of underground magmatic plumbing systems. These systems, essentially, consist of magma reservoirs which supply magma to the surface through volcanic conduits feeding volcanic eruptions. The mechanics and structure of plumbing systems remain largely unknown due to the obvious challenges involved in inferring volcanic processes occurring underground from observations at the surface. Nevertheless, volcanologists are beginning to gain a deeper understanding of the workings and architecture of magmatic plumbing systems from geophysical observations on active volcanoes, as well as from geological studies of the erosional remnants of ancient volcanic systems. In this work, I explore the relationship between the structure and mechanics of shallow plumbing systems and the volcanic eruptions these systems produce. I attempt to contribute to the understanding of this complex relationship by linking geological and geophysical observations of an eroded basaltic subvolcanic system, and the eruptive and tectonic activity of an active volcano, with mathematical models of magma ascent and stress transfer. The remarkable exposures of the Carmel outcrop intrusions, near the San Rafael swell, southeast Utah, U. S. A., allow detailed geological and geophysical observations of the roots of volcanic conduits that emerge from a subhorizontal magma feeder reservoir. These observations reveal a new mechanism for magma ascent and eruption triggering through gravitational instabilities created from an underlying feeding sill, and shed light on the mechanics of sill emplacement. Geophysical and geological observations of the 1999 and xii 1992 eruptions of the Cerro Negro volcano, Nicaragua, are used to explore the coupling between changes in the stress field and the triggering of volcanic eruptions, and magma ascent through the shallow crust. Modeling results of stress transfer and conduit flow highlight the importance of the surrounding stress field and geometry of the volcanic conduits that comprise shallow plumbing systems.

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Ce mémoire présente à la fois un état des lieux de la recherche scientifique sur le sujet, en réponse à une certaine demande sociale, une synthèse de notre propre activité, et un positionnement scientifique dans le champ de la géographie des risques. Il est alimenté par des réflexions théoriques et méthodologiques plus ou moins abouties, mais illustrées par des résultats concrets issus de nos recherches. Il laisse le champ à des questionnements scientifiques à portée opérationnelle et à des perspectives de recherche visant à mieux caractériser les systèmes de vulnérabilité aux catastrophes naturelles et faciliter ainsi les modes d'évaluation intégrée et spatialisée des risques naturels. Evaluation intégrée, car la vulnérabilité y est appréhendée selon des approches multi-critères propres à caractériser les multiples facettes et facteurs qui la déterminent. Evaluation spatialisée, car le risque est mis en carte, de différentes façons et à différentes échelles, toujours selon une démarche intégrée où se combinent, critères de vulnérabilité, enjeux et aléas.

Ruapehu is an active volcano located on the North Island of New Zealand, with the most recent major eruptions occurring in 1945, 1969, 1975, and 1995/96. Ruapehu is also home to the three major North Island ski areas, Whakapapa, Turoa, and Tukino. Because of the high frequency of eruptions, there is a significant volcanic hazard at the ski areas particularly from lahars which can form even after minor eruptions. Most recently, lahars have affected Whakapapa ski area in 1969, 1975, and 1995/96. The most significant risk at Turoa is from ballistic bombs due to the proximity of the top two T-Bars to the crater. Ash fall has also caused disruption at the ski areas, covering the snow and causing damage to structures. There is yet to be a death at the ski areas from a volcanic event; however the risk at the ski areas is too high to be completely ignored. The ski areas at Whakapapa and Turoa are currently operated by Ruapehu Alpine Lifts (RAL), who have been significantly improving their commitment to providing volcanic hazard training for their staff and preparing for handling a volcanic eruption. RAL is joined by the Institute of Geological Sciences (GNS) and the Department of Conservation (DoC) in trying to mitigate this risk through a range of initiatives, including an automated Eruption Detection System (EDS), linked to sirens and loudspeakers on Whakapapa ski areas, as well as by providing staff training and public education. The aim of this study was to provide RAL with recommendations to improve their staff training and warning system response. Staff induction week at both Turoa and Whakapapa ski areas was observed. Surveys were distributed and collected from staff at both ski areas, and interviews were conducted with staff at Whakapapa ski area. Data obtained from staff interviews and surveys provided the author with insight into staff's mental models regarding a volcanic event response. A simulation of the warning system was observed, as well as a blind test, to collect data on the effectiveness of training on staff response. Results indicated permanent and seasonal staff were knowledgeable of the volcanic hazards that may affect the ski areas, but had differing perspectives on the risk associated with those hazards. They were found to be confident in the initial response to a volcanic event (i.e. move to higher ground), but were unsure of what would happen after this initial response. RAL was also found to have greatly improved their volcanic hazard training in the past year, however further recommendations were suggested to increase training effectiveness. A training needs analysis was done for different departments at the ski areas by taking a new approach of anticipating demands staff may encounter during a volcanic event and complementing these demands with existing staff competencies. Additional recommendations were made to assist RAL in developing an effective plan to use when responding to volcanic events, as well as other changes that could be made to improve the likelihood of customer safety at the ski areas during an eruption.

Cette étude traite de la dynamique des éruptions volcaniques explosives, depuis les mécanismes de sub-surface jusqu’aux processus d’émission et de dispersion des pyroclastes. A cet effet un radar Doppler sol est utilisé (VOLDORAD), lequel renseigne sur la charge / vitesse des ejectas. Les données sont intégrées avec d’autres techniques géophysiques, et des modèles numériques sont développés afin de simuler les émissions pyroclastiques, générer des signaux radar synthétiques, pour finalement améliorer notre compréhension des processus qui leurs sont sous-jacents. L’Arenal (Costa Rica) est utilisé comme volcan cible, où de fréquentes éruptions de faible magnitude émettent des panaches de cendres et des projections balistiques jusqu’à quelques centaines de mètres au-dessus de l’évent. Dans un premier temps, nous combinons des données sismiques et radar afin d’explorer la relation entre les processus de conduit et les émissions pyroclastiques. Leurs interactions complexes sont interprétées via un modèle conceptuel, lequel décrit les fractures parsemant le bouchon de lave comme responsables du dégazage du système, et en retour des signaux sismiques et radar collectés (ces derniers dépendants de la charge en cendres des émissions de gaz). Par ailleurs, nous investiguons la dynamique des émissions pyroclastiques à travers l’étude de radargrammes Doppler. La distribution spatio-temporelle de la vitesse des ejectas indique l’existence de deux phénomènes aux dynamiques distinctes. Des modélisations numériques permettant la reconstruction de signaux synthétiques indiquent qu’il s’agit de l’émission simultanée de blocs balistiques et de panaches de cendres. Une procédure d’inversion de type Monte Carlo couplée d’un algorithme d’optimisation permet de retrouver les radargrammes synthétiques qui reproduisent au mieux ceux observés. Les résultats apportent des contraintes sur divers paramètres éruptifs, tels que les tailles, trajectoires, vitesses des ejectas et des gaz, ainsi que la vitesse / direction de dispersion des panaches de cendres par le vent. Enfin, nous discutons du potentiel des radars Doppler appliqués à la surveillance opérationnelle des émissions volcaniques. En particulier, la possibilité de quantifier les masses éjectées dans l’atmosphère ou retombant sur les flancs du volcan, fournit des paramètres éruptifs à la source pouvant alimenter les modèles de dispersion de panaches de cendres. / This study investigates the dynamics of explosive volcanic eruptions, from the sub-surface source mechanisms through to the emission dynamics and downwind dispersal of tephra. To this end, we use a ground-based Doppler radar (VOLDORAD) which informs on the loading / velocimetry of the expelled ejecta. Data are integrated with complementary geophysical techniques, and numerical models are developed to simulate pyroclastic emissions, generate synthetic radar data, and in turn enhance our understanding of the underlying dynamical processes. Arenal (Costa Rica) is used as a case study volcano, where frequent mildly-explosive eruptions commonly expel ash plumes and ballistic projections up to a few hundred meters above the vent. Firstly, we combine seismic and radar data to investigate the link between conduit processes and pyroclastic emissions. A conceptual model is proposed to account for their complex interplay, whereby fractures through a rigid lava cap control the system’s degassing, which in turn governs both the seismic and radar signals (the latter depending on the ash load carried by the gas). Secondly, we investigate the dynamics of pyroclastic emissions from the analysis of Doppler radargrams. Time-velocity distribution of the expelled tephra shows the signature of two distinct phenomena. Numerical modeling and computation of synthetic radargrams show that these are consistent with both ballistic projections and ash plume crossing the beam simultaneously, whose respective mass load can be derived. Inverse modeling using a nearneighborhood Monte Carlo procedure was used to find synthetic Doppler radargrams which best matched the observed ones. The results give constrains on eruptive parameters, such as the size, trajectory, exit velocities and source gas velocities of the ballistics, as well as the speed / direction of the ash cloud drifted by trade winds. Lastly, because Doppler radars are powerful tool for real-time allweather monitoring of volcanic activity, we address issues relative to the operational radar monitoring of ash plumes. In particular, the ability to remotely quantify the mass proportions of ejecta either falling on the slopes of the volcano or prone to be ejected into the atmosphere, gives source eruptive parameters which may feed volcanic ash dispersal models.

A erupção dentária depende de uma coordenada interação entre o germe dentário e o tecido ósseo da cripta que o envolve. Para que seja formada a via eruptiva, a reabsorção da porção oclusal da cripta óssea por osteoclastos é indispensável. Os bisfosfonatos são drogas com reconhecida capacidade de inibir a atividade clástica e foram empregados no presente estudo a fim de interferir no tecido ósseo da cripta alveolar durante a formação e erupção de molares de ratos. Doses diárias dos bisfosfonatos alendronato ou etidronato de 2,5 e 8 mg/kg, respectivamente, foram administradas a ratos recém nascidos. Os controles foram injetados com solução salina. Nos períodos de 4, 8, 14, 21 e 28 dias, as maxilas foram fixadas em 2,5% de formaldeído + 2% de glutaraldeído, 4% de formaldeído + 0,1% de glutaraldeído ou fixador Zamboni, descalcificadas em EDTA a 4,13% e processadas para análise em microscopias de luz, eletrônica de transmissão e confocal, histoquímica TRAP, imunocitoquímica para OPN, BSP, RANK, RANKL e OPG. Alguns espécimes não foram descalcificados para análise em microscopia eletrônica de varredura, ou congelados em nitrogênio líquido para extração e análise e da expressão de proteínas por Western Blotting. O etidronato ocasionou alterações no metabolismo ósseo da cripta que resultaram no atraso da erupção e da formação radicular em relação ao controle. O alendronato aumentou o número de osteoclastos no osso alveolar, porém a maioria apresentou estado latente, o que diminuiu a reabsorção óssea da cripta ao redor do germe dentário e impediu a erupção dos molares e a formação radicular. A expressão de RANKL, molécula ativadora dos osteoclastos, durante o início do processo eruptivo, diminuiu em comparação ao controle. Com a diminuição da remodelação óssea, o tecido apresentou distribuição de OPN e BSP típica de osso primário. Os resultados demonstram que a reabsorção óssea é importante em todos os pontos da cripta e não apenas em sua porção oclusal durante a formação da via eruptiva, para que a formação e erupção dentária ocorram adequadamente. / Tooth eruption depends on coordinated interactions between the tooth germ and the surrounding bony crypt. The formation of the eruptive pathway requires the resorption of the occlusal portion of the bony crypt by osteoclasts. The bisphosphonates are drugs with known capability to inhibit clastic activity, and were employed in the present study with the aim of interfering in the alveolar bony crypt during the formation and eruption of rat molars. Daily alendronate or etidronate 2.5 and 8 mg/kg doses, respectively, were administered to newborn rats. The controls were injected with saline solution. At 4, 8, 14, 21 and 28 days, the maxillae were fixed in 2.5% formaldehyde + 2% glutaraldehyde, 4% formaldehyde + 0,1% glutaraldehyde or Zambonis fixative, decalcified in 4.13% EDTA and processed for light, confocal and transmission electron microscopy analyzes, TRAP histochemistry, and immunocytochemistry for OPN, BSP, RANK, RANKL and OPG. Some specimens were left undecalcified for scanning electron microscopy analyzes, or frozen in liquid nitrogen for protein extraction and Western Blotting protein expression analyzes. Etidronate occasioned alterations in the alveolar bony crypt metabolism that resulted in the delay of tooth eruption. Alendronate increased osteoclast number in the alveolar bone; however, most of them were latent, which decreased the resorption of the bony crypt surrounding the tooth germ and impeded the eruption and root formation of the molars. The expression of RANKL, an osteoclast-activating molecule, was decreased. The inhibition of the bone remodeling resulted in typical primary bone OPN and BSP labeling pattern. These results demonstrate that bone resorption at the entire surface of the crypt, and not only during the eruptive pathway formation, is crucial for adequate tooth eruption and formation.

Ce travail de thèse a porté sur différents aspects de la prédiction des éruptions. La première partie, basée sur une approche statistique de l'information, nous a permis d'aborder la prédictabilité des éruptions de façon globale, et d'avoir une vision intégrée, à différentes échelles, de la dynamique éruptive. La dernière partie basée sur une approche déterministe du signal, nous a emmené de façon plus indirecte vers la prédiction des éruptions par le biais de l'analyse et la modélisation des comportements éruptifs d'un unique volcan à travers la sismicité. Ce travail de thèse nous a donc permis de traverser plusieurs échelles de temps et d'espace, en partant de la plus large, la Terre dans sa globalité, pour se concentrer ensuite sur le cas d'un volcan unique, le Piton de la Fournaise et finalement se focaliser sur une propriété spécifique de la sismicité du Piton de la Fournaise à travers la détermination des mécanismes source. Dans un premier temps, une analyse descriptive des propriétés statistiques de la dynamique éruptive à l'échelle mondiale et l'apparition de lois puissances à différentes échelles nous ont permis de relier la dynamique des éruptions à celle d'un système critique auto-organisé, justifiant de la difficulté rencontrée à prédire les éruptions de façon déterministe et de la nécessité de se tourner vers les méthodes statistiques. L'étude à l'échelle mondiale des lois d'Omori retrouvées pour la sismicité autour des éruptions, ainsi que l'analyse des propriétés de ces lois d'Omori en fonction de la taille des éruptions, suggèrent que l'énergie d'endommagement et de relaxation dans la croûte est distribuée en loi puissance autour des éruptions, mais avec des coefficients de chargement et de relaxation différents de la sismicité tectonique classique, et donc dépendant des processus qui génèrent l'endommagement. En zoomant sur trois observables du Piton de la Fournaise (sismicité, déformation et variations de vitesse sismique), nous avons montré que les comportement respectifs des observables imagent les différentes étapes du processus éruptif, pour différentes échelles de temps et d'espace. L'analyse des comportements pré-éruptifs et l'utilisation de méthodes de "pattern recognition" ont permis de mettre en évidence l'apport de la combinaison des informations des différents précurseurs dans l'amélioration des résultats de prédiction. Enfin, l'analyse plus spécifique et déterministe des mécanismes source au Piton de la Fournaise, à partir d'une méthode développée pour le contexte particulier d'une sismicité de magnitude très faible en milieu fortement hétérogène, a permis de mettre en évidence l'apparition de trois familles d'événements similaires. Deux de ces familles peuvent être interprétées comme l'ajustement du milieu au passage du dyke, la troisième famille correspondant à la signature de l'interaction entre les fluides et l'édifice volcanique au niveau du toit de la chambre magmatique. / This PhD work focused on several aspects of the eruptions prediction. It allowed us to consider different space scales from global scale to a single volcano, Piton de la Fournaise, through statistical approaches. We then focused more specifically on the volcano-seismicity associated to its eruptive processes, using deterministic methods. First, we analyzed the statistical properties of the eruptive dynamics at the global scale. The emergence of recurrent power laws allowed us to relate the eruptive dynamics to the SOC systems, thereby attesting for the difficulty to predict eruptions by means of deterministic methods. At the global scale, the study of the Omori-law found for eruptions foreshocks and aftershocks, along with the analysis of the parameters of those Omori laws given the size of eruptions, suggests that the damage and relaxation energy in the crust around eruption time and location is power-law distributed. However, the loading and relaxation coefficients are found different than for classical tectonic seismicity, thereby attesting their dependency to the damage processes. When zooming on three observables of Piton de la Fournaise volcano (seismicity, deformation and seismic velocity changes), me showed in a third part that the respective behaviors of the three observables respond to the different steps of the eruptive process, at different time and space scales. The analysis of the pre-eruptive behaviors of those forerunners under pattern recognition techniques enhanced the optimization of the prediction results by combining simultaneously their pre-eruptive information. Lastly, we performed a specific and deterministic study of the volcano-tectonic seismicity of Piton de la Fournaise through the assessment of the source mechanisms of the volcano-tectonic seismicity. Given the complexity of volcanic context, we developed a method to retrieve the source mechanisms of small and high-frequency seismic signals. Using this method three main families of events with different locations and times of occurrence emerge. Two of them may be interpreted as the readjustment of the crust during dyke opening whereas the third family is interpreted as the signature of fluids-rock interactions at the top of the magma Storage zone.

INTRODUÇÃO: As crianças pré-termo, principalmente aquelas de muito baixo peso (MBP) podem apresentar alterações no seu padrão craniofacial, no desenvolvimento da cavidade bucal e no padrão eruptivo dental. Este estudo teve como objetivos descrever as características faciais, palatinas e a erupção dentária em crianças pré-termo que receberam assistência respiratória; comparar os efeitos da ventilação mecânica invasiva (VMI) e do CPAP sobre as mesmas variáveis; observar o impacto do aleitamento, uso de chupeta e presença de displasia brocopulmonar em crianças pré-termo com idades entre 12 e 24 meses. MÉTODOS: Participaram deste estudo crianças pré-termo, procedentes do Ambulatório de Seguimento de Recém- Nascidos Pré-Termo do Hospital Universitário da Universidade de São Paulo e do Ambulatório de Seguimento dos Prematuros A5 RN 002 do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, com peso ao nascimento inferior a 2000g. Foram constituídos dois grupos a partir dos dados sociodemográficos coletados dos prontuários de internação neonatal das crianças participantes. O Grupo 1 (G1) constituise de 34 crianças pré-termo que receberam VMI por intubação orotraqueal (IOT) por um período igual ou maior que 7 dias, e o Grupo 2 (G2) é composto por 34 crianças pré-termo que receberam CPAP por um período de tempo igual ou maior que 72 horas. Foi realizada entrevista com a mãe ou responsável pela criança, com objetivo de obter as informações relativas à duração do aleitamento, uso da chupeta, presença/ausência de displasia broncopulmonar como sequela da prematuridade. As crianças foram submetidas a um exame de inspeção da cavidade bucal para detectar a presença de alterações no rebordo ou palato, para classificar o formato do palato (quadrado, estreito e ovoide) e para visualizar a erupção dos dentes decíduos, classificada em atrasada, normal ou adiantada para a idade. Foram realizadas medidas faciais, com emprego de um paquímetro, dos pontos antropométricos como: larguras facial e mandibular, terços superior, médio e inferior da face, altura facial e índice facial. Foi realizada análise descritiva e inferencial (teste t-Student, teste F da ANOVA, teste Mann- Whitney, Kruskal-Walis, teste exato de Fisher e o coeficiente de correlação de Pearson). Os cálculos foram realizados com auxílio do software R 3.1.1 (R Core Team, 2014). Utilizou-se nível de significância de 5% para o teste de hipóteses. RESULTADOS: Os grupos G1 e G2 foram homogêneos em relação ao gênero (p=1; feminino: n=17; masculino n=17 para ambos os grupos) e em relação à raça (p= 0,627; não caucasiano: n=14 CPAP; n=17 IOT). Porém, quando se analisou a duração da assistência respiratória, as crianças do G1 permaneceram um tempo médio de dias em IOT (25,3 ± 25,8) significantemente maior (p < 0,001) quando comparado ao CPAP. Em relação à erupção dentária, os grupos G1 e G2 foram homogêneos, p=1 (atrasada: 47,1%; normal: 38,2% e adiantada:14,7%), entretanto, o grupo G1 apresentou porcentagens significantemente maiores do formato do palato estreito (p=0,005) e valores significantemente maiores para a altura do terço inferior da face (p=0,019) quando comparadas às crianças do G2. As crianças com palato ovoide apresentaram um terço inferior da face significantemente menor (p = 0,038) quando comparado aos outros tipos de formato de palato, porém para as outras medidas da face e para os outros formatos de palato não houve diferença. Os grupos G1 e G2 não diferiram em relação às alteração de palato, medidas faciais e uso da chupeta. Da mesma maneira, o aleitamento materno não influenciou as medidas faciais da população estudada. Crianças submetidas à IOT, com sequela da DBP, apresentam altura do terço inferior da face significantemente maior (p= 0,019). CONCLUSÕES: As crianças pré-termo que receberam assistência respiratóra (CPAP ou IOT) não apresentam alterações em rebordo, palato, medidas faciais e na erupção dentária. Entretanto, quando estas foram submetidas à IOT, observou-se presença de palato de formato estreito e profundo, enquanto naquelas em CPAP o palato é de formato quadrado. As crianças pré-termo com hábitos nutritivos e não nutritivos não apresentam alteração no formato palatino nem nas medidas faciais. A presença da DBP em crianças submetidas à IOT acarreta maior altura no terço inferior da face / INTRODUCTION: Preterm children, especially those of very low birth weight, (VLBW), may show changes in the craniofacial pattern in the development of the oral cavity and tooth eruption pattern. This study aimed to describe the facial and palate characteristics as well as tooth eruption in preterm infants who have receiving mechanical ventilation; compare the effects of invasive mechanical ventilation (IMV) and CPAP on the same variables; observe the impact of breastfeeding, use of pacifier and presence of bronchopulmonary dysplasia in preterm children aged 12-24 months. METHODS: The study included preterm infants, coming from the Pre-Term Newborn Follow-up Clinic of the University Hospital at University of São Paulo and from the Preterm Follow-up Clinic A5 RN 002 of the Children\'s Institute of the Medical School of the University of São Paulo, weighting less than 2000g at birth. Based on the sociodemographic data collected from newborn hospital records of participating children, two groups were divided. Group 1 (G1) consisted of 34 preterm infants who received IMV by tracheal intubation (TI) for a period equal to or greater than 7 days and Group 2 (G2) consisted of 34 preterm infants who received CPAP for a period of time equal to or greater than 72 hours. An interview was conducted with the mother or the child\'s guardian in order to obtain information on breastfeeding duration, nursing nipple use, presence/absence of bronchopulmonary dysplasia as prematurity-related sequelae. The children underwent an oral cavity inspection to detect the presence of changes in alveolar ridge or palate, so as to sort palate shape (square, narrow, oval) and to view the eruption of primary teeth, classified as delayed, average or early for the age. Facial measures were taken with the use of a caliper on anthropometric points, such as facial and mandibular width, upper, middle and lower thirds of faces, facial height and facial index. A descriptive and inferential analysis was carried out (t-Student test, ANOVA F test, Kruskal-Wallis, Mann-Whitney test, Fisher\'s exact test and Pearson\'s correlation coefficient). Calculations were performed with the aid of the R 3.1.1 software (R Core Team, 2014). A 5% significance level was used to test the hypotheses. RESULTS: Groups G1 and G2 were homogeneous with respect to gender (p=1; female: n=17; male n=17 for both groups) and to race (p=0.627; non-Caucasian: n=14 CPAP; n=17 TI). However, when analyzing the duration of the mechanical ventilation, G1\'s children remained a significantly higher average of days in TI (25.3 ± 25.8) (p < 0.001) as compared to CPAP. Concerning tooth eruption, groups G1 and G2 were homogeneous, p=1, (delayed: 47.1%; average: 38.2% and early: 14.7%), however, G1 showed significantly higher percentages of narrow palate shape (p = 0.005) and significantly higher values for the height of the lower third of faces(p = 0.019) when compared to children of the G2. Children with oval palate have shown a significantly smaller lower third of the face (p = 0.038) when compared to other types of palate shapes, nevertheless, for other facial sizes and other palate shapes, no difference has been observed. The groups G1 and G2 did not differ with regard to palate change, facial sizes and use of pacifiers. Moreover, breastfeeding has also not affected the facial sizes of the study population. The height of the lower third of the face is significantly higher (p=0.019) in children with bronchopulmonary dysplasia sequelae who have received TI. CONCLUSIONS: Preterm infants who have received mechanical ventilation (CPAP or TI) have shown no changes on the ridge, palate, facial sizes and tooth eruption. However, when submitted to TI, the presence of narrow- and deep-shaped palate was noted, while infants who have undergone CPAP showed square-shaped palates. Preterm infants with nutritive and nonnutritive sucking habits have shown no changes in palatal shape or facial sizes. The presence of BPD in children who have undergone TI entails greater height in the lower third of the face

O objetivo geral desta pesquisa foi avaliar fatores associados à atividade de lesões de cárie não cavitadas, bem como, critérios para a sua avaliação em superfícies oclusais de molares permanentes. Para isso, dois estudos foram conduzidos. O primeiro estudo teve como objetivos: (1) avaliar a efetividade de um tratamento para pacientes com lesões de cárie em molares em diferentes estágios de erupção e (2) avaliar se o estágio de erupção e o acúmulo de biofilme estão associados à atividade de lesões de cárie em pacientes submetidos a um tratamento não invasivo. Já o segundo estudo teve como objetivo avaliar a associação entre dois critérios visuais para a determinação da atividade de lesões de cárie não cavitadas em molares permanentes. Para o primeiro estudo, foram selecionados 48 pacientes, com idades entre 5 e 13 anos, que apresentavam pelo menos um molar permanente com lesão não cavitada ativa na superfície oclusal. Os molares foram classificados quanto ao tipo, estágio de erupção, presença de biofilme e presença de lesão, bem como, sua condição de atividade. Os pacientes foram submetidos a um protocolo de tratamento não invasivo de 4 sessões com intervalos semanais baseado na educação para saúde bucal e fluorterapia. Após 3 semanas do término do tratamento, 39 pacientes foram re-examinados. Observou-se que os molares parcialmente erupcionados apresentaram maiores chances de permanecerem com lesão ativa após o protocolo de tratamento não invasivo quando comparados aos dentes totalmente em oclusão. Além disso, maior acúmulo de biofilme na superfície oclusal mostrou estar associado com maiores chances de uma lesão permanecer ativa após o tratamento quando comparada a ausência de biofilme visível. Para o segundo estudo, foram selecionados 39 pacientes, com pelo menos um molar permanente com lesão de cárie não cavitada em superfície oclusal, os quais foram classificados com relação à presença de lesões não cavitadas, bem como, sua condição de atividade segundo dois critérios: ICDAS-LAA e um critério padrão (características clínicas consenso na literatura). Os resultados mostraram fraca associação entre os dois critérios na determinação da atividade das lesões de cárie e baixa especificidade para o ICDAS-LAA. Com base nos resultados obtidos no primeiro estudo, pode-se concluir que: (1) o protocolo de tratamento não foi efetivo em inativar as lesões de cárie não cavitadas ativas de pacientes com molares parcialmente erupcionados e (2) foi encontrada uma forte associação entre molares permanentes parcialmente erupcionados, maior acúmulo de biofilme e a presença de lesões ativas mesmo após o tratamento instituído. A partir 7 dos resultados do segundo estudo, concluiu-se que o critério ICDAS-LAA não foi apropriado para a determinação da atividade de lesões de cárie não cavitadas em superfícies oclusais de molares permanentes, visto que parece superestimar a atividade das lesões. / The aim of this study was to evaluate associated factors to non-cavitated caries lesions activity as well as different criteria for its assessment on occlusal surfaces of permanent molars. Therefore, two studies were carried out. The aims of the first study were: (1) to evaluate the effectiveness of a treatment for patients with non-cavitated caries lesions on permanent molars in different eruption stages and (2) to evaluate if the eruption stage and biofilm accumulation are associated to caries lesions activity in patients that received a non-operative treatment. The second study aimed at evaluating the association between two visual criteria in assessing non-cavitated caries lesions activity on permanent molars. For the first study, 48 patients aged from 5 to 13 years old were selected. Those patients should have presented at least one permanent molar with an active non-cavitated caries lesion on its occlusal surface. Molars were classified according to type, eruption stage, biofilm accumulation and presence of lesion as well as their activity status. All patients received a weekly non-operative treatment during 4 weeks based on oral health instructions and fluoride application. After 3 weeks, 39 patients were re-assessed. After the treatment, partially erupted molars were more prone to show active caries lesions than molars in full occlusion. Likewise, high biofilm accumulation was more associated to the presence of active caries lesions when compared to the absence of visible biofilm. For the second study, 39 patients with at least on permanent molar with non-cavitated caries lesion on occlusal surface were selected. Molars were classified according to the presence of caries lesions as well as to their activity status following two criteria: ICDAS-LAA and a standard criterion (based on clinical characteristics which are consensus in the literature). The results showed a weak association between both criteria in assessing caries lesions activity and low specificity for ICDAS-LAA. Based on the results from the first study, it can be concluded that: (1) treatment was not effective in arrest active non-cavitated caries lesion in patients with partially erupted molars and (2) a strong association between partially erupted molars, high biofilm accumulation and presence of active lesions was observed even after the treatment. From the results of the second study, it can be concluded that ICDAS-LAA criterion was not appropriate for activity assessment of non-cavitated caries lesions on occlusal surfaces of permanent molars, since this criterion seems to overestimate caries lesions activity.

INTRODUÇÃO: As crianças pré-termo, principalmente aquelas de muito baixo peso (MBP) podem apresentar alterações no seu padrão craniofacial, no desenvolvimento da cavidade bucal e no padrão eruptivo dental. Este estudo teve como objetivos descrever as características faciais, palatinas e a erupção dentária em crianças pré-termo que receberam assistência respiratória; comparar os efeitos da ventilação mecânica invasiva (VMI) e do CPAP sobre as mesmas variáveis; observar o impacto do aleitamento, uso de chupeta e presença de displasia brocopulmonar em crianças pré-termo com idades entre 12 e 24 meses. MÉTODOS: Participaram deste estudo crianças pré-termo, procedentes do Ambulatório de Seguimento de Recém- Nascidos Pré-Termo do Hospital Universitário da Universidade de São Paulo e do Ambulatório de Seguimento dos Prematuros A5 RN 002 do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, com peso ao nascimento inferior a 2000g. Foram constituídos dois grupos a partir dos dados sociodemográficos coletados dos prontuários de internação neonatal das crianças participantes. O Grupo 1 (G1) constituise de 34 crianças pré-termo que receberam VMI por intubação orotraqueal (IOT) por um período igual ou maior que 7 dias, e o Grupo 2 (G2) é composto por 34 crianças pré-termo que receberam CPAP por um período de tempo igual ou maior que 72 horas. Foi realizada entrevista com a mãe ou responsável pela criança, com objetivo de obter as informações relativas à duração do aleitamento, uso da chupeta, presença/ausência de displasia broncopulmonar como sequela da prematuridade. As crianças foram submetidas a um exame de inspeção da cavidade bucal para detectar a presença de alterações no rebordo ou palato, para classificar o formato do palato (quadrado, estreito e ovoide) e para visualizar a erupção dos dentes decíduos, classificada em atrasada, normal ou adiantada para a idade. Foram realizadas medidas faciais, com emprego de um paquímetro, dos pontos antropométricos como: larguras facial e mandibular, terços superior, médio e inferior da face, altura facial e índice facial. Foi realizada análise descritiva e inferencial (teste t-Student, teste F da ANOVA, teste Mann- Whitney, Kruskal-Walis, teste exato de Fisher e o coeficiente de correlação de Pearson). Os cálculos foram realizados com auxílio do software R 3.1.1 (R Core Team, 2014). Utilizou-se nível de significância de 5% para o teste de hipóteses. RESULTADOS: Os grupos G1 e G2 foram homogêneos em relação ao gênero (p=1; feminino: n=17; masculino n=17 para ambos os grupos) e em relação à raça (p= 0,627; não caucasiano: n=14 CPAP; n=17 IOT). Porém, quando se analisou a duração da assistência respiratória, as crianças do G1 permaneceram um tempo médio de dias em IOT (25,3 ± 25,8) significantemente maior (p < 0,001) quando comparado ao CPAP. Em relação à erupção dentária, os grupos G1 e G2 foram homogêneos, p=1 (atrasada: 47,1%; normal: 38,2% e adiantada:14,7%), entretanto, o grupo G1 apresentou porcentagens significantemente maiores do formato do palato estreito (p=0,005) e valores significantemente maiores para a altura do terço inferior da face (p=0,019) quando comparadas às crianças do G2. As crianças com palato ovoide apresentaram um terço inferior da face significantemente menor (p = 0,038) quando comparado aos outros tipos de formato de palato, porém para as outras medidas da face e para os outros formatos de palato não houve diferença. Os grupos G1 e G2 não diferiram em relação às alteração de palato, medidas faciais e uso da chupeta. Da mesma maneira, o aleitamento materno não influenciou as medidas faciais da população estudada. Crianças submetidas à IOT, com sequela da DBP, apresentam altura do terço inferior da face significantemente maior (p= 0,019). CONCLUSÕES: As crianças pré-termo que receberam assistência respiratóra (CPAP ou IOT) não apresentam alterações em rebordo, palato, medidas faciais e na erupção dentária. Entretanto, quando estas foram submetidas à IOT, observou-se presença de palato de formato estreito e profundo, enquanto naquelas em CPAP o palato é de formato quadrado. As crianças pré-termo com hábitos nutritivos e não nutritivos não apresentam alteração no formato palatino nem nas medidas faciais. A presença da DBP em crianças submetidas à IOT acarreta maior altura no terço inferior da face / INTRODUCTION: Preterm children, especially those of very low birth weight, (VLBW), may show changes in the craniofacial pattern in the development of the oral cavity and tooth eruption pattern. This study aimed to describe the facial and palate characteristics as well as tooth eruption in preterm infants who have receiving mechanical ventilation; compare the effects of invasive mechanical ventilation (IMV) and CPAP on the same variables; observe the impact of breastfeeding, use of pacifier and presence of bronchopulmonary dysplasia in preterm children aged 12-24 months. METHODS: The study included preterm infants, coming from the Pre-Term Newborn Follow-up Clinic of the University Hospital at University of São Paulo and from the Preterm Follow-up Clinic A5 RN 002 of the Children\'s Institute of the Medical School of the University of São Paulo, weighting less than 2000g at birth. Based on the sociodemographic data collected from newborn hospital records of participating children, two groups were divided. Group 1 (G1) consisted of 34 preterm infants who received IMV by tracheal intubation (TI) for a period equal to or greater than 7 days and Group 2 (G2) consisted of 34 preterm infants who received CPAP for a period of time equal to or greater than 72 hours. An interview was conducted with the mother or the child\'s guardian in order to obtain information on breastfeeding duration, nursing nipple use, presence/absence of bronchopulmonary dysplasia as prematurity-related sequelae. The children underwent an oral cavity inspection to detect the presence of changes in alveolar ridge or palate, so as to sort palate shape (square, narrow, oval) and to view the eruption of primary teeth, classified as delayed, average or early for the age. Facial measures were taken with the use of a caliper on anthropometric points, such as facial and mandibular width, upper, middle and lower thirds of faces, facial height and facial index. A descriptive and inferential analysis was carried out (t-Student test, ANOVA F test, Kruskal-Wallis, Mann-Whitney test, Fisher\'s exact test and Pearson\'s correlation coefficient). Calculations were performed with the aid of the R 3.1.1 software (R Core Team, 2014). A 5% significance level was used to test the hypotheses. RESULTS: Groups G1 and G2 were homogeneous with respect to gender (p=1; female: n=17; male n=17 for both groups) and to race (p=0.627; non-Caucasian: n=14 CPAP; n=17 TI). However, when analyzing the duration of the mechanical ventilation, G1\'s children remained a significantly higher average of days in TI (25.3 ± 25.8) (p < 0.001) as compared to CPAP. Concerning tooth eruption, groups G1 and G2 were homogeneous, p=1, (delayed: 47.1%; average: 38.2% and early: 14.7%), however, G1 showed significantly higher percentages of narrow palate shape (p = 0.005) and significantly higher values for the height of the lower third of faces(p = 0.019) when compared to children of the G2. Children with oval palate have shown a significantly smaller lower third of the face (p = 0.038) when compared to other types of palate shapes, nevertheless, for other facial sizes and other palate shapes, no difference has been observed. The groups G1 and G2 did not differ with regard to palate change, facial sizes and use of pacifiers. Moreover, breastfeeding has also not affected the facial sizes of the study population. The height of the lower third of the face is significantly higher (p=0.019) in children with bronchopulmonary dysplasia sequelae who have received TI. CONCLUSIONS: Preterm infants who have received mechanical ventilation (CPAP or TI) have shown no changes on the ridge, palate, facial sizes and tooth eruption. However, when submitted to TI, the presence of narrow- and deep-shaped palate was noted, while infants who have undergone CPAP showed square-shaped palates. Preterm infants with nutritive and nonnutritive sucking habits have shown no changes in palatal shape or facial sizes. The presence of BPD in children who have undergone TI entails greater height in the lower third of the face