Objetivo: Evaluar el espesor del esmalte en dientes humanos permanentes, en las porciones vestíbulo/palatino-linguales, según los tercios coronales cervical, medio e incisal. Materiales y métodos: Una muestra de 75 dientes sanos, divididos en primeras premolares superiores (n=25), primeras molares superiores (n=25) y primeras molares inferiores (n=25). Fueron cortadas en láminas de 1 mm de espesor en una máquina de corte digital. Las mediciones se realizaron según los tercios coronales, cervical, medio e incisal, utilizando un calibrador digital para realizar la medición en (mm). Se realizó una estadística descriptiva (media y desviación estándar) de las variables de estudio. Resultados: El mayor espesor del esmalte en el sentido vestibular se encuentra en el tercio incisal, con una media de 1.53 mm + 0.20 perteneciente a las molares inferiores y el menor valor se encuentra en el tercio cervical con el promedio de 0.64 mm + 0.08 correspondiente a las primeras molares superiores. Mientras que, en el sentido palatino/lingual, el mayor valor encontrado es en el tercio incisal con el promedio de 1.50 mm + 0.19, perteneciente a las primeras molares inferiores, y el menor valor es en el tercio cervical con una media de 0.65 mm + 0.09 perteneciente a las primeras molares superiores. Conclusiones: El espesor del esmalte en el sentido vestibular como palatino/lingual es mayor en el tercio incisal y menor en el tercio cervical para los tres grupos de piezas dentarias. Este conocimiento permitirá realizar desgaste al diente de una manera más conservadora realizando tratamientos altamente funcionales y estéticos / Objective: to assess the thickness of the permanent human tooth enamel, in portions vestibular/palatal-lingual, according to the thirds coronal cervical, middle and incisal. Materials and Methods: A sample of 75 healthy teeth, divided into first premolars (n=25), first molars (n=25) and first molars (n=25). Were cut in strips of 1 mm thick in a digital cutting machine. The measurements were made according to the thirds coronal, cervical, middle and incisal, using a digital gauge to perform the measurement in (mm). A descriptive statistics (mean and standard deviation) of the study variables. Results: The increased thickness of the enamel on the vestibular sense is in the incisal third, with an average of 1.53 mm 0.20 belonging to the molars and the lower value is found in the cervical third with an average of 0.64 mm 0.08 corresponding to the first molars. While, in the palatal/lingual sense, the highest value found is in the incisal third with an average of 1.50 mm 0.19, belonging to the first molars, and the lowest value is in the cervical third with an average of 0.65 mm 0.09 belonging to the first molars. Conclusions: The thickness of the enamel on the vestibular sense as palatal/lingual is greater in the incisal third and lower in the cervical third for the three groups of dental pieces. This knowledge will allow for wear to the tooth in a more conservative doing treatments highly functional and aesthetic.

The study objective was to determine cementum-dentin wall thickness along the furcation groove in maxillary bifurcated first premolars after preparation with three successively larger, 0.04 tapered, nickel titanium rotary files. Pre-instrumentation and post-instrumentation imaging was accomplished utilizing Cone Beam Computed Tomography. All data was analyzed using an ANOVA. Instrumentation resulted in a significant reduction in dentin-cementum wall thickness (p < .001). At mid-groove, predicted dentin-cementum wall thickness (95% CI) was equal to or less than the proposed standard (0.50 mm) for apical file sizes 30, 35, and 40 respectively. Instrumentation of the mid-groove in maxillary first premolars reduces dentin-cementum wall thickness to levels that may be insufficient to ensure tooth integrity.

Ante el fracaso de un tratamiento y retratamiento endodóntico el protocolo adecuado que figura antes de llegar a una exodoncia es la cirugía apical. En la actualidad con una buena preparación científica, clínica y con la ayuda de la tecnología con los diversos equipos y puntas ultrasónicas en la especialidad de endodoncia; se pretende alcanzar una cirugía apical exitosa con una confección de una caja para obturación retrógrada óptima y con una mínima formación de micro fisuras destinarias a nivel del tercio apical de la raíz; para ello se utilizaron las puntas ultrasónicas diamantadas de retro preparación apical Woodpecker y Helse en el equipo ultrasónico Woodpecker UDSE; para determinar la formación de micro fisuras (MF); posterior a la retro preparación apical en premolares. El objetivo planteado de esta investigación fue evaluar la aparición de micro fisuras en la superficie apical posterior a la retro preparación; utilizando las puntas ultrasónicas diamantadas Woodpecker y Helse. La metodología que se empleó fue evaluativa – experimental in vitro; con una muestra no probabilística de treinta premolares, durante los meses de setiembre a octubre del 2017. La superficie radicular de las cavidades de la obturación retrógrada se analizaron visualmente con microscopía electrónica de barrido (SEM) y así poder detectar las micro fisuras dentinarias que se pudieron encontrar. Los resultados evidenciaron que hubo una mayor cantidad de micro fisuras por grupo después de la retro preparación apical y posterior al proceso de metalizado cuando se utilizó puntas diamantadas Helse y una menor cantidad de micro fisuras después de la retro preparación apical y posterior al proceso de metalizado cuando se utilizó puntas diamantadas Woodpecker. / Tesis

Magister Scientiae Dentium - MSc(Dent) / Aim: The aim of this study was to assess the effect of retraction of anterior teeth on pharyngeal airway dimensions, after orthodontic treatment of bimaxillary protrusion cases by means of the extraction of four premolars. Method: A total of 88 lateral cephalometric radiograph pairs, consisting of a pre-treatment and post-treatment radiograph taken for orthodontic treatment of bimaxillary protrusion by means of extraction of four premolars, was used. The pharyngeal airway space, measured across three different levels, as well as the length of the maxilla and mandible were assessed for changes from pre-treatment to post-treatment. Pearson’s correlation coefficient was used to determine the degree to which the change in pharyngeal airway space was associated with the change in maxilla or mandible length. Results: The pre-treatment average pharyngeal airway space measurements were recorded as 15.23mm for the Superior Pharyngeal Airway Space, 11.63mm for the Middle Pharyngeal Airway Space and 13.56mm for the Inferior Pharyngeal Airway Space. The average reduction in the pharyngeal airway space was noted as 1.21mm, 1.64mm and 2.23mm respectively. All with statistically significant P values of <0.001.

Made available in DSpace on 2017-07-24T19:21:57Z (GMT). No. of bitstreams: 1 Patricio Runnacles.pdf: 1899405 bytes, checksum: f12074a5a86f43aa25ef7c17d1ba8e87 (MD5) Previous issue date: 2014-12-17 / Objective: This in vivo study evaluated the baseline pulp temperature in human intact upper premolars and the pulp temperature rise induced by light emitted by a high power polywave Light Emitting Diode (LED) light curing unit (LCU); also, the possible correlation between the change in temperature (ΔT) and the volume of the crown and the pulp chamber ex vivo. Material and methods: after approval of the local Ethics Committee was obtained (protocol #255,945), upper right and left first premolars requiring extraction for orthodontic reasons from 8 volunteers (n=15) received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A small, occlusal preparation was made using high-speed hand piece, under constant air-water spray, until a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system (Temperature Data Acquisition - Thermes WFI, Physitemp) was inserted directly into the coronal pulp. Once the baseline pulp temperature was stable, the buccal surface was exposed to polywave light from a LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs: 10-s either in low (10-s/L) or High (10-s/H); 5-s-Turbo (5-s/T); and 60-s-High (60-s/H) intensities, allowing a 7-min span between each exposure. Peak PT values and PT increases from baseline (ΔT) after exposure were subjected to 1-Way, repeated measures ANOVAs, and Bonferroni's post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. the teeth were extracted according to treatment plan. The crown and pulp volumes were measured using micro-tomography scanner, and pulp chamber / crown volume ratio was determined. Afterwards, premolar buccal-lingual, cervico-occlusal, mesio-distal dimensions as well as between cusp distances were measured using a digital caliper. Results: consistent temperature below body temperature, resulting in an average core temperature of 35 ° C (+ 0.7 ° C) was found. All modes of activation of the LED promoted significant temperature rise in the pulp chamber. A positive correlation between energy density and thermal variation was observed. No correlation was observed between coronal volume, the pulp chamber with temperature changes. A significant negative correlation was noted between pulp temperature changes when 10-s/L was used and VL. / Objetivo: Este estudo in vivo avaliou a temperatura basal da polpa em pré-molares hígidos superiores em humanos e o aumento da temperatura induzida pela luz emitida por um fotopolimerizador à base de Diodo Emissor de Luz (LED) polywave de alta potência; além disso, a possível correlação entre a variação de temperatura (ΔT) e o volume da coroa e da câmara pulpar ex vivo. Material e métodos: após aprovação da Comissão de Ética da Universidade Estadual de Ponta Grossa (UEPG) (protocolo #255,945), pré-molares direito e esquerdo de 8 pacientes voluntários (n=15), que necessitavam de extrações por motivos ortodônticos, receberam anestesia infiltrativa e intraligamentar e isolamento absoluto. Um pequeno acesso oclusal com exposição pulpar foi realizado usando alta-rotação, sob spray de ar e água constante, até atingir uma mínima exposição da polpa. Inseriu-se uma sonda estéril de um termopar wireless (Temperature Data Acquisition - Thermes WFI, Physitemp) diretamente no interior da câmara pulpar. Após a estabilização da temperatura basal da polpa, a face vestibular foi exposta à luz de um fotopolimerizador LED polywave (Bluephase 20i, Ivoclar Vivadent), usando modos de exposição selecionados: 10s em baixa potência (10s/L), 10s em alta potência (10s/H), 5s em potência turbo (5s/T) e 60s em alta potência (60s/H), respeitando um intervalo de 7 min entre cada exposição. A temperatura pulpar foi registrada a cada 0,2 s. Os valores absolutos e a variação da temperatura pulpar após exposição foram submetidos a análise estatística fator único (ANOVA) com medidas repetidas seguida pelo teste de Bonferroni (α=0,05). A correlação entre as densidades de energia aplicadas e os valores das variações de aumento de temperatura foi estabelecida por uma análise de regressão linear. Após as exodontias realizadas de acordo com os planos de tratamento, os elementos dentários (n=11) foram armazenados em Timol 0,1% e as dimensões mésio-distal da face oclusal (MD), cérvico-oclusal (CO), e vestíbulo-lingual (VL) da coroa dos dentes foram medidas com um paquímetro digital. Os volumes coronário e da câmara pulpar foram determinados por meio de microtomografia computadorizada (μCT) dos espécimes. Resultados: foi encontrada uma temperatura basal média consistente abaixo da temperatura corporal, de 35°C (+ 0,7°C). Todos os modos de ativação do LED promoveram aumento significativo de temperatura na câmara pulpar. Foi observada uma correlação positiva entre densidade de energia e variação térmica. Não houve correlação dos volumes coronal e da câmara pulpar com as variações térmicas, mas foi encontrada uma correlação negativa entre a medida VL das coroas e o ΔT no modo de exposição 10s/L.

Magister Scientiae Dentium - MSc(Dent) (Orthodontics) / Orthodontic treatment has the ability to improve the aesthetics and the function of patients. In order to create space, orthodontic treatment often requires removal of teeth. The most common teeth removed for orthodontic treatment are the premolars. It has become popular to remove second premolars in certain cases where the soft tissue profile should not be altered. The Damon self-ligating orthodontic system is renowned for not requiring dental extractions in the majority of cases. The effect of extractions on the soft tissue profile of patients, in conjunction with using the Damon system, has therefore not been researched. It is important to understand the effect that orthodontic treatment and extractions can have on the soft tissue profile of patients. This effect can accurately be determined by making use of the soft tissue cephalometric analysis, developed by Dr Reed A. Holdaway in 1983.

The purpose of this study was to compare the thickness of dentin removed from the buccal root of bifurcated maxillary first premolars (BMFP) in the area of furcation groove after instrumentation with WaveOne and LightSpeed LSX files utilizing limited field cone beam computerized tomography. All data was analyzed using repeated-measured mixed-model ANOVA and differences were described using Tukey’s multiple comparison procedure. The thickness of dentin removed with LightSpeed LSX files (0.1 mm) was significantly less than the thickness of dentin removed with WaveOne files (0.2 mm). To conclude, LSX files remove a more predictable and consistent thickness of dentin from the buccal root of BMFP, irrespective of the pre-instrumentation thickness of dentin and the file size when compared to WO files that remove a more variable thickness of dentin.

The purpose of this study was to use existing Cone Beam Computer Tomography images to determine the vertical and horizontal location of the mental foramen in relation to the mandibular first and second premolars, as well as the distance in millimeters from the apex of each. The distance from the inferior border of the foramen to the inferior border of the mandible was also recorded. The average distance from the apices of the mandibular first and second premolars to the mental foramen was 7.43mm (SD= 1.97) and 5.30mm (SD=1.65) respectively. The foramen was located 11.44mm (SD=1.49) from the inferior border of the mandible. The foramen was in line with the apex of the mandibular second premolar 41% of the time. The mental foramen was further away from the inferior border of the mandible in males and older patients. Mental foramina seemed to be positioned more apically and distally in older patients.

Introduction: This study aimed to compare the third molars angulation and eruption status in Class I and II malocclusions in orthodontic treatment with and without first premolar extractions. Methods: The sample was comprised by 96 patients divided into four groups: Group 1 Class I malocclusion treated with first premolars extraction; Class I malocclusion treated without extractions; Group 3 Class II malocclusion treated with first premolars extraction; Group 4 Class II malocclusion treated without extractions. Panoramic radiographs were used to evaluate third molars mesiodistal angulations at T1, T2 and at T3. Third molar eruption status was assessed in dental casts. Intergroup angulations and eruption status comparisons were performed using ANCOVA followed by Tukey tests and Kruskal-wallis test, respectively. Results: Significantly greater mesial angulation and percentage of erupted right maxillary third molars were found in Class I extraction group. Significantly greater distal angulation and percentage of erupted right mandibular third molars were found in Class II extraction group. Conclusion: Class I and II extraction treatment exhibited more favorable angulations and greater number of erupted third molars than nonextraction treatment. Regardless the treatment performed third molars showed a more uprighted position in each malocclusion type. / Introdução: Este estudo comparou as angulações mesiodistais e o grau de irrompimento dos terceiros molares nas más oclusões de Classe I e II no tratamento ortodôntico com e sem extrações dos primeiros pré-molares. Métodos: Foram avaliados 96 pacientes divididos em quatro grupos. Grupo 1, indivíduos com má oclusão de Classe I tratada com extrações dos primeiros pré-molares. Grupo 2, má oclusão de Classe I tratada sem extrações. Grupo 3 indivíduos com má oclusão de Classe II tratada com extração dos primeiros pré-molares. Grupo 4 má oclusão de Classe II tratada sem extrações. As angulações mesiodistais dos terceiros molares foram avaliadas em radiografias panorâmicas e o grau de irrompimento em modelos de estudo. Para comparar as angulações e o grau de irrompimento entre os grupos, utilizou-se o teste ANCOVA seguido do teste Tukey e o teste de Kruskal-wallis, respectivamente. Resultados: O grupo 1 apresentou significativamente maior angulação mesial do terceiro molar superior direito assim como uma porcentagem maior de molares irrompidos. O grupo 2 apresentou significativamente maior angulação distal do terceiro molar inferior direito e uma porcentagem maior de molares irrompidos. Conclusão: Os tratamentos de Classe I e II com extrações apresentaram angulações mais favoráveis e uma porcentagem maior de terceiros molares irrompidos do que os tratamentos sem extrações. Independentemente do tratamento realizado, os terceiros molares apresentaram uma posição mais vertical.

abstract: The pattern and strength of genetic covariation is shaped by selection so that it is strong among functionally related characters and weak among functionally unrelated characters. Genetic covariation is expressed as phenotypic covariation within species and acts as a constraint on evolution by limiting the ability of linked characters to evolve independently of one another. Such linked characters are "constrained" and are expected to express covariation both within and among species. In this study, the pattern and magnitude of covariation among aspects of dental size and shape are investigated in anthropoid primates. Pleiotropy has been hypothesized to play a significant role in derivation of derived hominin morphologies. This study tests a series of hypotheses; including 1) that negative within- and among-species covariation exists between the anterior (incisors and canines) and postcanine teeth, 2) that covariation is strong and positive between the canines and incisors, 3) that there is a dimorphic pattern of within-species covariation and coevolution for characters of the canine honing complex, 4) that patterns of covariation are stable among anthropoids, and 5) that genetic constraints have been a strong bias on the diversification of anthropoid dental morphology. The study finds that patterns of variance-covariance are conserved among species. Despite these shared patterns of variance-covariance, dental diversification has frequently occurred along dimensions not aligned with the vector of genetic constraint. As regards the canine honing complex, there is no evidence for a difference in the pleiotropic organization or the coevolution of characters of the complex in males and females, which undermines arguments that the complex is selectively important only in males. Finally, there is no evidence for strong or negative pleiotropy between any dental characters, which falsifies hypotheses that predict such relationships between incisors and postcanine teeth or between the canines and the postcanine teeth. / Dissertation/Thesis / Ph.D. Anthropology 2011