Objetivo: Investigar o efeito da cirurgia ortognática sobre a atividade eletromiográfica integrada (EMGI) dos músculos mastigatórios e a força de mordida isométrica máxima (FMIM) e analisar se estes parâmetros alcançam níveis normais após a cirurgia. Modelo: Os pacientes foram avaliados antes da cirurgia ortognática (PRÉ) e 3 a 9 meses após (PÓS). Diferenças foram consideradas significantes ao nível de 5%. Ambiente/Local: Laboratório de Fisiologia, Hospital de Reabilitação de Anomalias Craniofaciais, Universidade de São Paulo, Bauru. Pacientes/Participantes: Dezesseis pacientes com mal-oclusão dentária e 11 indivíduos com oclusão dentária normal (controle). Intervenções: Os pacientes submeteram-se à osteotomia do tipo Le Fort I Variáveis: 1) Atividade EMGI dos músculos masseteres e temporais na contração voluntária isométrica máxima (CVIM) e na percussão voluntária e rítmica dos dentes (PVRD); 2) FMIM medida, bilateralmente, na região dos 1º e 2º premolares. Resultados: Comparativamente ao grupo controle, na CVIM e na PVRD, a atividade EMGI do músculo masseter nos pacientes foi menor no PRÉ e no PÓS, a atividade do músculo temporal foi menor no PÓS e a FMIM foi menor no PRÉ e no PÓS. Na CVIM e na PVRD, os valores no PÓS foram significantemente menores no músculo temporal, comparativamente ao PRÉ, não ocorrendo o mesmo com o músculo masseter. A FMIM no lado direito foi menor no PÓS, comparativamente ao PRÉ, não sendo observadas diferenças no lado esquerdo. Conclusões: A cirurgia ortognática modificou a atividade EMG do músculo temporal e a FMIM do lado direito, entretanto, a função muscular não normalizou após a cirurgia. / Objective: To investigate the effect of the orthognathic surgery on the integrated electromyographic (IEMG) activity of the masticatory muscles and on the maximum isometric bite force (MIBF) and to analyze if these parameters reach normal values following surgery. Design: IEMG activity and bite force were measured before orthognathic surgery (PRE) and 3 to 9 months after (POST). Differences were considerated significant at a level of 5%. Setting: Laboratory of Physiology, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru. Patients: Sixteen patients with malocclusion and 11 individuals with normal dental occlusion, used as controls. Interventions: Le Fort I osteotomy. Main outcome measures: 1) IEMG activity of the masseter and temporal muscles measured during maximum isometric voluntary clench (MIVC), and voluntary and rhythmic percussion of the teeth (VRPT), and 2) MIBF, measured bilaterally in the area of the 1st and 2nd premolars. Results: During MIVC and VRPT activities the masseter IEMG activity in the group of patients with malocclusion was smaller at PRE and POST, temporal IEMG activity was smaller only at PRE, when compared to the normal group. MIBF was smaller at PRE and POST. Median value observed at POST during MIVC and VRPT activities was significantly small from PRE for the temporal muscle. No significant difference was observed between PRE and POST values for the masseter muscle. MIBF on the right side at POST was smaller that at PRE; no differences were seen on the left side. Conclusions: The orthognathic surgery modified the temporal muscle IEMG activity and MIBF recorded on the right side of the dental arch, however, normal muscular function was not achieved after surgery.

Objetivo: Avaliar a força de mordida (FM) em crianças com fissura labiopalatina (FLP) reparada. Material e Métodos: Cento e cinquenta crianças, com idade entre 6-12 anos, com e sem FLP, foram divididos em 5 grupos: 1) grupo controle (CON) : 34 crianças sem FLP; 2) grupo com fissura pré-forame incisivo (FPré): 31 crianças com fissura envolvendo o pré-maxila; 3) grupo FLP transforame incisivo unilateral (FTU): 36 crianças com FLP transforame incisivo unilateral completa; 4) grupo FLP transforame incisivo bilateral (FTB): 32 crianças com FLP transforame incisivo bilateral completa; e 5) grupo fissura pós-forame incisivo (FPós): 17 crianças com fissura pós-forame incisivo completa. A FM, expressa em Kgf, foi avaliada por meio de gnatodinamômetro (IDDK, Kratos, Cotia, SP, Brasil). Foram feitas 3 medidas consecutivas, com um intervalo de 1 minuto entre elas, para evitar a fadiga do voluntário. A medida mais elevada foi considerada para análise. Para os grupos CON, FTB, FPré e FPós, a FM foi obtida na região anterior e posterior da maxila. Para o grupo FTU, FM foi avaliada nas regiões anterior e posterior de ambos os segmentos, a fim de se distinguir os valores de FM em regiões diferentemente afetadas pela presença da fissura. As diferenças entre os grupos foram avaliadas através do teste ANOVA de medidas repetidas. O teste de Tukey foi utilizado para aferir correlação entre as variáveis. Para a correlação entre FM e idade, foi utilizado o teste de Correlação de Pearson. Em todos os casos, foram considerados significativos valores de p<0.05. Resultados: Não foram encontradas diferenças significativas entre a FM posterior do grupo CON (30,7±9,2) e dos grupos FPré (35,3±11,6), FTU (lado fissurado: 26,5±10,7 e lado não-fissurado: 29,6±10,0), FTB (25,6±5,9) e FPós (29,1±12,0). Entretanto, valores de FM significantemente maiores foram observados no grupo FPré, quando comparado a FTU e FTB. Não foram observadas diferenças significantes entre o lado fissurado e não fissurado do grupo FTU. Finalmente, em todos os grupos, os valores de FM da região anterior da maxila foram menores, quando comparados à região posterior. Conclusão: Neste trabalho os valores de FM em crianças com FLP foram equivalentes àqueles encontrados em crianças sem essa anomalia. / Objective: To assess the bite force (BF) of children with repaired cleft lip and palate (CLP) Design: One hundred and fifty children, aged 6-12 years, with and without CLP, were divided into the following 5 groups: 1) control group (CON): 34 children without CLP; 2) cleft lip group (CL): 31 children with cleft lip involving the pre-maxilla; 3) unilateral CLP group (UCLP): 36 children with complete unilateral CLP; 4) bilateral CLP group (BCLP): 32 children with complete bilateral CLP; and 5) cleft palate group (CP): 17 children with complete cleft palate. BF, expressed in Kgf, was assessed with a gnathodynamometer (IDDK, Kratos, Cotia, SP, Brazil), before alveolar bone grafting. For CON, BCLP, CL and CP groups, BF was obtained in the anterior and posterior region of the maxilla. For the UCLP group, BF was assessed in the anterior and posterior regions of both segments. Differences among groups were evaluated by ANOVA test, and Tukeys test was used to assess any correlations among variables. Correlation between BF and age were assessed using Pearson Product-Moment Correlation. In all cases, values of p < 0.05 were considered for analysis. Results: Contrary to what was expected, no differences of posterior BF were observed among CON group (30.7 ± 9.2) and CL (35.3 ± 11.6), UCLP (cleft side: 26.5 ± 10, 7 and noncleft side: 29.6 ± 10.0), BCLP (25.6 ± 5.9) and CP (29.1 ± 12.0) groups. However, a stronger BF was observed in the CL group when compared to the UCLP and BCLP groups. Next, no differences were observed between the cleft side and the noncleft side in the UCLP group. Lastly, in all groups, BFs from the anterior region of the maxilla were less when compared to the posterior regions. Conclusion: The BF of children with CLP is no different from children without CLP.

A função mastigatória é uma das principais constituintes do sistema estomatognático e impreterivelmente antecede a absorção de nutrientes pelo organismo humano. A força de mordida é um componente dessa função e um indicador clínico do funcionamento desse sistema. Em sujeitos com deformidade dentofacial, a mastigação está prejudicada devido ao desequilíbrio das relações esqueléticas e musculares maxilomandibulares e da oclusão. A abordagem investigativa tridimensional é única que possui a vantagem de avaliar a morfologia facial nos três planos do espaço, tal como se configura a face humana e a deformidade dentofacial. Portanto, o objetivo deste trabalho foi analisar a variação da morfologia facial em diferentes medidas tridimensionais, assim como verificar possível assimetria na força de mordida e diferenças na distribuição de força e área dos contatos oclusais entre sujeitos com deformidades dentofaciais padrão dentoesquelético II, padrão dentoesquelético III e controles. O estudo foi realizado com 77 sujeitos que compuseram dois diferentes grupos, a saber: deformidade dentofacial (DDF) e controle (GC). O grupo com o diagnóstico de deformidade dentofacial (DDF) foi subdividido segundo a classificação da mesma. Assim, 20 sujeitos classe II (4 homens e 16 mulheres, com média de idade de 26 anos) integraram o subgrupo DDF II, 32 classe III (15 homens e 16 mulheres, com média de idade de 27 anos) formaram o DDF III e 25 voluntários saudáveis (9 homens e 16 mulheres, idade média de 24 anos) compreenderam o GC. Todos foram submetidos à avaliação tridimensional da morfologia facial, por meio de escaneamento facial a laser, medidas de força de mordida pelo gnatodinamômetro, análise da distribuição de força oclusal e área de contato dentário pelo sistema T-Scan. As comparações entre GC e DDF foram realizadas pela Análise de Variância (ANOVA) para amostras independentes. O teste de correlação de Spearman foi aplicado para avaliar as possíveis associações entre as medidas de força de mordida e as medidas antropométricas, além da análise de regressão linear múltipla para identificar as variáveis antropométricas associadas à força de mordida. Foi adotado nível de significância de 5%. Na investigação da morfologia, os sujeitos com DDF apresentaram características específicas e compatíveis com as classes II e III esqueléticas, com aumento da altura facial principalmente em retrognatas. A força de mordida foi menor para o grupo DDF, porém não se diferenciou entre os grupos e não houve assimetrias nesse quesito. A área de contato oclusal evidenciou-se mais deficitária para sujeitos com padrão dentoesquelético III, porém a distribuição de força oclusal não demonstrou diferenças entre os grupos. Pode-se concluir o método de análise tridimensional confirmou achados específicos relevantes no que diz respeito às deformidades dentofacias estudadas. E as proporções faciais foram consideradas fatores influenciadores da magnitude da força de mordida em sujeitos com a deformidade dentofacial. / The masticatory function is the one of the main constituents of stomatognathic system and necessarily precedes the absorption of nutrients by the human organism. Bite force is a component of this function and a clinical parameter of this system\'s health. In dentofacial deformity, chewing is impaired due the imbalance of skeletal and muscular maxillomandibular relationships and of the occlusion. Three-dimensioal investigative approach is unique and has the advantage about the evaluation of facial morphology in the three planes of space, such as the configuration of the human face and dentofacial deformity. Therefore, the objective of this study was to analyze the variation of facial morphology in different three-dimensional measurements, as well as to verify possible asymmetry in bite force and the difference in the distribution of force in dental arc and occlusal contact area between subjects with dentofacial deformities class II, class III and control. The study was performed with 77 subjects who composed two different groups: dentofacial deformity (DDF) and control (CG). The group of dentofacial deformity (DDF) was subdivided according to its classification. Thus, 20 class II subjects (4 men and 16 women, mean age of 26 years old) were included in the DDF II subgroup, 32 class III (15 men and 16 women, mean age of 27 years old) formed DDF III, and 25 healthy volunteers (9 men and 16 women, mean age of 24 years old) comprised the CG. All were submitted to the threedimensional assessment of the facial morphology by laser scanning, bite force measurements by gnatodynamometer, analysis of occlusal force distribution and occlusal contact area by the T-Scan system. Comparisons between CG and DDF groups were performed by Analyses of Variance (ANOVA) for independent samples. Spearman\'s correlation test was applied to evaluate the possible association between bite force and anthropometric measurements, as well as multiple linear regression analysis to identify the anthropometric variables associated to the bite force. A significance level of 5% was adopted. In the investigation of morphology the subjects with dentofacial deformities presented specific features and compatible with the skeletal class II and skeletal class III, with increase of facial height, mainly in retrognathic subjects. The bite force was lower for DDF, did not differentiate between the groups and there were no asymmetries about them. The occlusal contact area was found to be poorer for subjects with class III deformity, but the occlusal force distribution did not show differences between the groups. It can be concluded the three-dimensional analysis method confirmed specific and relevant findings to the studied dentofacial deformities. And the facial proportions were considered factors influencing the magnitude of the bite force in subjects with deformity.

Orientador: Fausto Bérzin / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-19T14:48:48Z (GMT). No. of bitstreams: 1 Dressano_Danilo_M.pdf: 1270747 bytes, checksum: 4699fc2bda742e1bb38aee6d188ed0a2 (MD5) Previous issue date: 2012 / Resumo: Eletromiografia de superfície é uma ferramenta que auxilia um estudo aprofundado sobre patologias em áreas que trabalham com o movimento muscular. Muitos estudos relatam que indivíduos com padrões craniométricos distintos podem apresentar diferenças no padrão do movimento mandibular. Foram analisados 31 sujeitos, divididos em três grupos (09 dolicocéfalos, 14 mesocéfalos e 08 braquicéfalos), gêneros masculino e feminino, entre 18 e 28 anos de idade, Classe I de Angle, saudáveis, não apresentando disfunção temporomandibular, bruxismo e/ou apertamento dental e sem agenesia. As dimensões cranianas foram tomadas com o compasso antropométrico de Willis. Para a investigação da atividade elétrica foi realizada eletromiografia de superfície no músculo masseter e um transdutor de mordida posicionado em todos os dentes a fim de captar o biofeedback das forças oclusais. Todos os voluntários foram orientados a aplicar e manter uma força oclusal de 20 Kgf por 5 segundos. Para análise da amplitude média do sinal eletromiográfico e da força muscular foi calculado o valor do Root Means Square (RMS). Para cada grupo foram relacionados os valores do RMS no movimento de contração voluntária e aplicação de força oclusal, e os valores no movimento de mastigação comparados. Com os dados obtidos foi possível concluir que existem diferenças significativas em indivíduos classe I de Angle e com distintos padrões craniométricos. Nesse estudo o grupo dolicocéfalo foi capaz de exercer e sustentar uma força oclusal maior que os outros dois grupos, porém com um valor de RMS mais elevado, sugerindo maior esforço muscular. O grupo braquicéfalo exerceu e manteve uma força oclusal pouco abaixo do estabelecido, porém com um valor de RMS médio próximo ao grupo mesocéfalo, que exerceu menor força. Isso pode sugerir um melhor aproveitamento da energia muscular e uma maior estabilidade da força muscular durante o movimento de contração voluntária submáxima no grupo braquicéfalo / Abstract: Surface electromyography is a hardware that supports a deeper study about pathologies in areas that works with the muscular movement. Several studies reports that subjects with distinct craniometrical patterns may exhibit different movement functions. Thirty one subjects were analysed, divided in three groups (09 dolichocephalics, 14 mesocephalics and 08 brachicephalics), genders masculine and feminine, between 18 and 28 years old, Angle's class I, healthy, no presence of temporomandibular disfunction, bruxism, clenching or dental agenesis. The cranial dimensions were taken with the anthropometrical Willis's compass. To the investigation was performed surface electromyography in the masseter muscle and a bite transducer positioned in all teeth to get the biofeedback of the oclusal forces. All volunteers were instructed to implement and maintain an oclusal force of 20 Kgf for 5 seconds. To analyze the mean amplitude of electromyographic signal and the muscular force was calculated the Root Mean Square (RMS) value. For each group were related the RMS value in the volunteer muscular contraction movement and implement of oclusal force and the values of the mastication movements were compared. With the data it was concluded that there is significant differences in individuals Angle's class I with different craniometrical patterns. In this study the dolichocephalic group was capable to prosecute and maintain a superior oclusal force than the two other groups, however the RMS value plus elevated, suggesting a higher muscular effort. The brachicephalic group prosecuted and maintained a little below oclusal force value than the instructed, however with the mean RMS value closer to the mesocephalic group, who exerted less force. It may suggest a better use of the muscular energy and higher muscular force stability during the submaximal voluntary contraction in the brachicephalic group / Mestrado / Anatomia / Mestre em Biologia Buco-Dental

Online learning is increasingly prevalent in education and one area which stands to benefit from this approach is work based learning. This area is characterised by time-poor students and a requirement for flexibility in time and location. Online learning could be considered a solution to these issues, providing greater flexibility than campus based offerings, but it is not a panacea. Online learning suffers from a range of issues, particularly in retention, generally seeing attrition rates between 10% and 20% higher than traditional education. This research investigates an emerging method for delivering online education to work based learners and how it compares to traditional methods with respect to engagement. The method is named bite sized learning, and the core principle is that lessons are delivered in very short, bite sized chunks. These chunks are delivered on a daily basis, comprised of content, guidance and practical tasks. Each chunk also includes a requirement for social interaction with a learning peer group. This work takes an action research approach, combined with grounded theory and mixed methods. The author proposes the use of a methodology "stack", utilising each of these approaches, which will be shown to enable rigorous evaluation and development of an emerging educational method. The mixed methods employed comprise learning analytics and qualitative course evaluation survey data. To begin the work, a series of identical bite sized courses are quantitatively analysed in order to propose a reliable measure of engagement for bite sized learning. This concludes that a measure of daily participants produces the most effective results. Using the methodology "stack," the body of this research takes a 3 stage practice-based approach. A set of live bite sized learning courses are studied, via the "stack", producing an evaluation, an experiment and a resulting theory for bite sized learning. The evaluation reveals current patterns of engagement within bite sized learning, and enables the development of an early theory. The results of this inform the development of an experiment, intended to test the effect of the daily format versus a simpler form of bite sized learning, delivering all content at the beginning. These experimental results, allied with further qualitative data, allow further development and refinement of a bite sized learning theory. It is discovered that bite sized learning does offer a number of unique advantages to work based learners when compared to traditional methods. It does also, however, come with difficulties. The advantages include increased participation, as well as an increase in discipline and priority around online learning. The difficulties centre around participation in social tasks and on daily participation. Both reduce flexibility, but hold the advantages of increased priority and increased learning for some. The research concludes with the presentation of a three path theoretical model of bite sized learning, each level suited to a particular context and course aim. The paths develop in sequence, and educators may choose the path which best suits their own teaching environment. The resulting paths force a choice between emphasising flexibility, involvement or learning, and advice is offered on how to choose the ideal model based on the learners involved.

Orientador: João Neudenir Arioli Filho / Resumo: O posicionamento e forma oclusal dos dentes posteriores, assim como a utilização de implantes dentários, podem contribuir com uma adequada função mastigatória de usuários de próteses totais. Neste contexto, os objetivos do estudo clínico randomizado cruzado foram: (1) avaliar a eficiência mastigatória (EM), força máxima de mordida (FM) de portadores de próteses totais duplas e portadores de prótese total no arco superior e overdenture retida por um implante no arco inferior, confeccionadas com oclusão balanceada bilateral e lingualizada e (2) avaliar a autopercepção da saúde bucal destes indivíduos. Vinte e seis pacientes receberam próteses totais duplas, com dentes intercambiáveis na prótese inferior, permitindo a troca dos padrões oclusais. Posteriormente, cada paciente recebeu um implante na região de sínfise mandibular e as próteses totais inferiores foram convertidas em overdentures implantorretidas. A EM foi realizada através da mastigação de cubos de silicone de condensação e mensurada pelo método das peneiras, enquanto que a FM foi mensurada pela utilização de um gnatodinamômetro. Para avaliação da autopercepção de saúde bucal foi utilizado o índice de determinação da saúde bucal geriátrica (GOHAI). Os resultados mostram que não houve diferença estatística para EM (p=0,813) e FM (p=0,074) em usuários de próteses totais convencionais quando comparados diferentes padrões oclusais. Para overdentures mandibulares, em relação aos padrões oclusais, também não foram obtidos ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The positioning and occlusal design of posterior teeth, as well as the use of dental implants, may contribute with an adequate masticatory function of removable complete denture wearers. In this context, the aims of this randomized crossover clinical trial were: (1) evaluate the masticatory efficiency (ME) and maximum bite force (BF) of wearers of maxillary and mandibular removable complete dentures and wearers of maxillary complete denture and single-implant mandibular overdenture, made with bilateral balanced occlusion and lingualized balanced occlusion, (2) evaluate the self-perception of these. Twenty six patients received maxillary and mandibular removable complete dentures, with interchangeable teeth in the mandibular prosthesis, allowing the exchange of occlusal patterns. Subsequently, each patient received an implant in the mandibular symphysis region and the mandibular complete dentures were converted into implant retained overdentures. ME was performed by the chewing of condensation silicone cubes and measured by sieve method, while the BF was measured with a gnathodynamometer. To evaluate the self-perception of oral health the General Oral Health Assessment Index (GOHAI) was used. The results show that there was no statistical difference for ME (p = 0.813) and BF (p=0.074) in wearers of removable complete dentures when different occlusal patterns were compared. For mandibular overdentures, in relation to occlusal patterns, no significant results were also obtained ... (Complete abstract click electronic access below) / Doutor

To investigate the bacterial composition of infected and non-infected dog bite wounds (DBW), a prospective study was performed on dogs with various grades of bite wounds presenting at the Onderstepoort Veterinary Academic Hospital, University of Pretoria, and a nearby animal shelter. Fifty dogs with bite wounds inflicted within the previous 72 hours were selected. This represented 104 wounds. Wounds were clinically graded according to severity. Swabs were collected from all wounds for bacterial culture and cytology. Infection was diagnosed if 2 of the following 3 criteria were met: macroscopic purulence, microscopic presence of phagocytosed bacteria, or pyrexia. Non-infected wounds were either classed as sterile (established by culture) or contaminated (culture positive but bacteria not phagocytosed on cytology). To determine the origin of the bacteria, swabs were collected from the skin near the wounds and gingiva of 15 bite victims. All swabs were cultured aerobically and anaerobically and all aerobic cultures were evaluated for antimicrobial susceptibility using the Kirby Bauer disk diffusion test. The victims were predominately male, uncastrated, small-breed dogs. Of the 104 wounds studied, 21 were judged to be infected and 83 non-infected. Infected wounds were significantly more likely to culture positive (Fisher's exact test: p = 0.02). Sixteen per cent of wounds did not culture bacteria, 67% grew aerobes only, 1% anaerobes only and 67% a mixture of aerobes and anaerobes. A total of 213 isolates were cultured representing a mean of 2 isolates per wound. Of the aerobe species cultured, 22%, 19% and 17% belonged to the genera of Pasteurella, Streptococcus and Staphylococcus respectively. The species of Pasteurella multocida (66%) and Staphylococcus intermedius (70%) were predominant. Pasteurella canis and pyogenic streptococci were common in infected wounds, whereas Bacillus spp., Actinomyces spp. and oral streptococci were usually found in contaminated wounds. Three anaerobic genera were cultured, namely, Prevotella, Clostridium and Peptostreptococcus, and were usually associated with wounds with dead space. This study also describes the first documented case of Capnocytophaga canimorsus in an infected dog bite wound. Notably clinical and cytological assessment was capable of establishing whether antimicrobials were required or not. Although no single antimicrobials was considered to be effective against all the bacteria, amoxycillin plus clavulanic acid, 1st and 3rd generation cephalosporins, ampicillin or amoxycillin and potentiated sulphonamides gave the best in vitro sensitivity results. / Dissertation (MMedVet(Surgery) Small Animal Surgery)--University of Pretoria, 2007. / Companion Animal Clinical Studies / unrestricted

The purpose of the current study was to gain a better understanding of speech adaptation by examining kinematic and acoustic adaptation to bite block perturbation over time. Fifteen native American English speakers (7 female, 8 male) with no history of speech, language, or hearing deficits participated in the study. Custom bite blocks were created for speakers which created a 10mm interincisal gap when inserted. Speakers produced five repetitions of the sentence, I say ahraw /ərɑ/ (as part of a larger set) prior to bite block insertion, immediately following bite block insertion, 2-mintues post insertion, 4-minutes post insertion, 6-minutes post insertion, and immediately following bite block removal. Participants’ speech was audio-recorded, and their lingual articulatory movements were measured with a Northern Digital Instruments Wave electromagnetic articulograph. The VC syllable /ɑɪs/ was analyzed kinematically from the midpoint of the /ɑɪ/ diphthong through production of /s/ using a custom Matlab application. Kinematic data were obtained via sensor coils placed in the tongue back, tongue mid, tongue front, jaw, lower lip and upper lip. Measures of displacement (mm), maximum velocity (mm/sec), and jaw contribution to the tongue and lower lip (mm) were taken during each recording. Spectral mean (Hz), standard deviation, skewness, and kurtosis were calculated for the central 50% of each /s/ production using acoustic analysis software. Kinematic analysis revealed no significant change in tongue measures upon bite block insertion or during the 6-minute adaptation period. In contrast, significant acoustic changes were observed upon bite block insertion and during the following 6 minutes, demonstrating adaptation over time. The changes observed in acoustic measures may have been a result of tongue shape changes and subsequent adaptations that were not detected via kinematic analysis. Future studies may provide further insight into the tongue’s ability to compensate for bite block perturbation by examining the relationship between mandibular positioning and tongue shape.

The research in this master's thesis examines the mechanics of primate and early hominid feeding within the context of hypotheses about australopithecine diets. Specifically, this work will be helpful in testing the hypothesis that derived craniodental features in australopithecines are adaptations for feeding on hard, brittle, seasonally available foods. These foods may have been “fallback” items that could be fed upon during periods of scarcity, and thus their consumption may have been ecologically important to survival of early humans. In order to test the fallback theory, accurate estimates of bite force to initiate a crack in a hard food source using different tooth shapes is essential. These estimates help test the theory in two ways. First, the estimation of bite force for different tooth profiles helps in explaining effect of tooth morphology on fracture of hard food sources. This will test the premise that some species have more efficient tooth shapes for fracturing hard food than other species. Second, the obtained bite force will be used as an input to full scale finite element skull model of different species. Stress and strain distributions in critical regions of the skull will be helpful in understanding feeding adaptations of the different species during evolution. In this work a fast and accurate finite element analysis method was developed to estimate bite force required to initiate crack in a hard food source like the macadamia nut with different tooth morphologies. The proposed research will help in understanding the effect of tooth shape on the bite force required to initiate a crack in a hard food source In first experiment we simulated nut biting behavior found in ancient hominid by indenting macadamia nuts with aluminum alloy replicas of primate teeth. Finite element analysis simulation of the biting behavior provided insight into stress profile in the nut at the time of fracture. The results were statistically inconclusive due to huge variation in thickness, diameter and material properties of macadamia nut. In order to study effect of teeth shape on bite force, another study was performed in this work where four different hominoid species namely A.afransis, A.africanus, A.boisei and A.robustus of similar age level, were considered. Cast iron replicas of these hominoid teeth were created. In order to eliminate variability in thickness, diameter and material properties, we used acrylic hemispheres as a macadamia nut substitute. Statistical significance testing and FEA revealed that flatter teeth produces significantly lower force required to fracture acrylic hemisphere as compared to pointed and sharp teeth with comparable fracture stress. Results suggest that pointed teeth produces higher stresses in the food resulting in lower force required to fracture but at the same time stresses in teeth is also high increasing the probability of enamel failure. During the evolution teeth might have evolved to obtain optimum shape which provides tread off between minimum force required to fracture hard food items and minimum stress in enamel to reduce probability of enamel fracture Past work in estimating bite force is limited to experimental testing. Physical testing of bite force is tedious and time consuming. The proposed combination of physical testing and supporting finite element analysis will be helpful in reducing lengthy physical testing. The main advantage of this method is the comparatively low computational cost and the ability to estimate full field stresses and strains, as opposed to measuring surface strain at specific points. As our modeling and experimental methods become more refined, we anticipate being able to assess the degree to which tooth morphology affects the force needed to fracture hard food items, thereby providing insights into the dietary adaptations of living and extinct primates, including fossil humans.

During recent years of schizophrenia research, many etiologies have been emphasized, some of them implicating infectious and autoimmune diseases. Many different infectious agents have been examined, but the root seems to stem from the secondary autoimmune deregulation, which can be caused by different infectious agents. Among the effects that autoimmune deregulation has on the body, one prominent effect is on the brain, resulting in either severe or mild encephalitis. The mild encephalitis that has been implicated as one of the causes of schizophrenia-spectrum disorders has been associated with different pathogens, many of which can be transmitted by the household cat. Thus in the present research we have used the schizotypy personality construct model as an analog for schizophrenia spectrum disorders, and the relationship between current schizotypy and childhood household cat interactions were examined. An online questionnaire was completed by 356 undergraduate students and assessed the current schizotypy using the Schizotypal Personality Questionnaire Brief Revised (SPQ-BR), as well as questions about cat ownership and cat bites (puncturing skin) prior to age 13. While no significant relationship was found between childhood cat ownership and current schizotypy, individuals endorsing a cat bite prior to age 13 (N = 66) reported a significantly higher level of current overall schizotypy, which was largely driven by the Disorganized factor of the SPQ-BR.. This relationship should be explored further by examining the antibodies and sera of individuals with the schizophrenia spectrum disorder.