Among the most prevalent and devastating types of human birth defects are those affecting the mouth and face, such as orofacial clefts. Children with malformed orofacial structures undergo multiple surgeries throughout their lifetime and struggle with facial disfigurements, speech, hearing, and eating problems. Therefore, facilitating new research in cranio- and orofacial development is paramount to prevention and treatment of these types of birth defects in humans. Xenopus laevis has emerged as a new tool for dissecting the mechanisms governing facial development. Thus, molecular analyses accompanied by quantitative assessment of morphological changes during orofacial development of this species could be very powerful for understanding how these defects arise. In this dissertation, I present such a study. I first establish a quantitative protocol to describe size and shape changes in facial morphology of wild-type Xenopus embryos. I then utilize this method on embryos in which retinoic acid signaling or folate metabolism have been disrupted to correlate morphological changes with their underlying mechanisms. Finally, I demonstrate the utility of Xenopus as a system for chemical genomics to uncover other regulators of orofacial development.

<p>The mouth, throat, and face contain numerous muscles that participate in a large variety of orofacial behaviors. The jaw and tongue can move independently, and thus require a high degree of coordination among the muscles that move them to prevent self-injury. However, different orofacial behaviors require distinct patterns of coordination between these muscles. The method through which motor control circuitry might coordinate this activity has yet to be determined. Electrophysiological, immunohistochemical, and retrograde tracing studies have attempted to identify populations of premotor neurons which directly send information to orofacial motoneurons in an effort to identify sources of coordination. Yet these studies have not provided a complete picture of the population of neurons which monosynaptically connect to jaw and tongue motoneurons. Additionally, while many of these studies have suggested that premotor neurons projecting to multiple motor pools may play a role in coordination of orofacial muscles, no clear functional roles for these neurons in the coordination of natural orofacial movements has been identified.</p><p>In this dissertation, I took advantage of the recently developed monosynaptic rabies virus to trace the premotor circuits for the jaw-closing masseter muscle and tongue-protruding genioglossus muscle in the neonatal mouse, uncovering novel premotor inputs in the brainstem. Furthermore, these studies identified a set of neurons which form boutons onto motor neurons in multiple motor pools, providing a premotor substrate for orofacial coordination. I then combined a retrogradely traveling lentivirus with a split-intein mediated split-Cre recombinase system to isolate and manipulate a population of neurons which project to both left and right jaw-closing motor nuclei. I found that these bilaterally projecting neurons also innervate multiple other orofacial motor nuclei, premotor regions, and midbrain regions implicated in motor control. I anatomically and physiologically characterized these neurons and used optogenetic and chemicogenetic approaches to assess their role in natural jaw-closing behavior, specifically with reference to bilateral masseter muscle electromyogram (EMG) activity. These studies identified a population of bilaterally projecting neurons in the supratrigeminal nucleus as essential for maintenance of an appropriate level of masseter activation during natural chewing behavior in the freely moving mouse. Moreover, these studies uncovered two distinct roles of supratrigeminal bilaterally projecting neurons in bilaterally synchronized activation of masseter muscles, and active balancing of bilateral masseter muscle tone against an excitatory input. Together, these studies identify neurons which project to multiple motor nuclei as a mechanism by which the brain coordinates orofacial muscles during natural behavior.</p> / Dissertation

As fissuras orofaciais não-sindrômicas (FO-NS) correspondem a 70% de todos os casos de FO, possuem etiologia complexa e pouco compreendida, sendo consideradas de herança multifatorial com forte influência de fatores genéticos e ambientais. Apesar de estudos de análise de ligação e associação apontarem vários loci de susceptibilidade às FO-NS, o componente genético ainda não está totalmente explicado. Fatores ambientais também possuem um importante papel na etiologia das FO, e alguns já foram replicados em várias populações. Fatores como exposição materna ao álcool, drogas, tabaco, medicamentos, desnutrição e baixo nível socioeconômico são alguns dos fatores já associados a esta condição. As infecções periodontais são comuns em mulheres grávidas e estão associadas a parto prematuro, baixo peso fetal e, mais recentemente, foram reportadas como fator de risco aumentado para FO-NS nos fetos. Adicionalmente, o avanço das tecnologias de sequenciamento do DNA melhorou exponencialmente a compreensão do microbioma humano e sua influência no estado de saúde e doença, e, mais especificamente, o conhecimento sobre o impacto do microbioma na gravidez. O objetivo deste projeto foi identificar novos fatores etiológicos genéticos e ambientais das FO-NS. Para isso, primeiramente, sequenciamos 68 genes candidatos a FO por sequenciamento de nova geração em 193 indivíduos com FO-NS familial. Nós encontramos enriquecimento significativo de variantes raras e patogênicas de perda de função nos indivíduos com FO-NS e observamos que essas variantes estão em genes intolerantes a esse tipo de mutação. Também reportamos novas variantes raras do tipo perda de função no gene ARHGAP29 e sua importância na susceptibilidade as FO-NS familiais. Além disso, sugerimos o uso de um ponto de corte baseado no escore pLI do banco de dados ExAC como parâmetro para priorizar variantes em estudos de FO-NS familiares, assumindo modelo de herança mono ou oligogênico. Adicionalmente, estudamos o microbioma oral de mães de crianças com FO-NS e mães de crianças sem malformações, utilizando o sequenciamento da subunidade 16S do rRNA das bactérias com o objetivo de verificar diferenças consistentes na composição do microbioma oral de mães de crianças com FO-NS, levando em consideração a presença ou não de doenças infecciosas periodontais maternas. A casuística foi composta de 6 mães de recém-nascidos de até 1 mês que apresentaram FO-NS ao nascimento e mães de crianças sem qualquer malformação congênita. As análises de alfa e beta diversidades não demonstraram diferença significativa na composição do microbioma oral de mães de crianças com FO-NS e mães de crianças controle, contudo observamos que o grupo com infecções periodontais possui a diversidade taxonômica mais abundante do que o grupo hígido. Em resumo, nesse estudo piloto não foi possível identificar alterações no microbioma oral como um fator etiológico das FO-NS. Novas análises em uma casuística maior são necessárias para a confirmação desse achado / The non-syndromic orofacial clefts (nsOFC) correspond to 70% of all OFC cases, have complex etiology and are poorly understood, being considered multifactorial inheritance with a strong influence of genetic and environmental factors. Although linkage and association analysis studies point to several nsOFC susceptibility loci, the genetic component is not yet fully explained. Environmental factors also play an important role in OFC etiology, and some have been replicated in several populations. Factors such as maternal exposure to alcohol, drugs, tobacco, drugs, malnutrition and low socioeconomic status are some of the factors already associated with this condition. Periodontal infections are common in pregnant women and are associated with preterm birth, low birth weight and, more recently, have been reported as an increased risk factor for nsOFC in fetuses. Additionally, the advancement of DNA sequencing technologies has exponentially improved the understanding of the human microbiome and its influence on health and disease status, and, more specifically, knowledge about the impact of the microbiome on pregnancy. The objective of this project was to identify new genetic and environmental etiological factors of nsOFC. For this, we first sequenced 68 candidate genes by next generation sequencing in 193 individuals with familial nsOFC. We found significant enrichment of rare and pathogenic loss of function variants in individuals with nsOFC and we observed that these variants were in genes intolerant to this type of mutation. We also reported new rare loss-of-function variants in the ARHGAP29 gene and its importance in the liability of familial nsOFC. In addition, we suggested the use of a cutoff point based on the ExAC database pLI score as a parameter to prioritize variants in familial nsOFC studies, assuming a mono or oligogenic inheritance model. In addition, we studied the oral microbiome of 6 mothers of newborns up to 1-month-old with nsOFC and 6 mothers of newborns without congenital malformations using the 16S rRNA sequencing in order to verify consistent differences in the composition of the oral microbiome of mothers of children with nsOFC, taking into account the presence or absence of maternal periodontal infectious diseases. The analysis of alpha and beta diversities did not show a significant difference in the composition of the oral microbiome of mothers of nsOFC children and mothers of control children, however, we observed that the group with periodontal infectious diseases has more abundant taxonomic diversity than the healthy group. In summary, in this pilot study, it was not possible to identify alterations in the oral microbiome as an etiological factor of FO-NS. New analyzes in a larger cohort are necessary to confirm this finding

A tese divide-se em duas partes: 1) Relações entre leitura orofacial e leitura alfabética, vocabulário auditivo, consciência fonológica, memória de reconhecimento visual de figuras e de pseudofiguras, e compreensão de leitura de sentenças; 2) Escrita sob ditado e relações com leitura orofacial. Na Parte 1, 157 crianças de 6, 7 e 8 anos de idade de NSE muito elevado, foram avaliadas em leituras orofacial e alfabética, vocabulário auditivo, consciência fonológica, memória de reconhecimento visual, e compreensão de leitura de sentenças. Foram empregados: Prova de Leitura Orofacial, Teste de Vocabulário por Leitura Orofacial versão 1A computadorizada, Teste de Competência de Leitura de Palavras e Pseudopalavras, Teste de Vocabulário Auditivo Usp, Prova de Consciência Fonológica por Escolha de Figuras (PCFF-o), Teste Computadorizado de Memória de Reconhecimento de Figuras, e Teste de Compreensão de Leitura de Sentenças. Resultados revelaram que: 1) O léxico ortográfico aumenta sistematicamente de modo de modo monotônico desde o acaso aos 6 anos para 7 anos e daí para 8 anos; 2) A competência mais fortemente associada à leitura orofacial é a leitura de itens escritos; 3) O desenvolvimento das competências de leitura fonológica e lexical é diretamente proporcional ao desenvolvimento das habilidades metafonológicas no nível fonêmico; 4) Os subtestes de leitura fonológicos (decodificação) são mais fortemente associados com leitura orofacial. Assim, quanto maior a habilidade de converter grafemas em fonemas (rota fonológica de leitura por decodificação), maior a habilidade de converter optolalemas em fonemas para compreeder fala por leitura orofacial; 5) O desenvolvimento da leitura orofacial correlaciona-se mais fortemente com habilidades metafonológica de Transposição e Adição Fonêmicas. Logo, consciência fonêmica é precursora da leitura orofacial. Transposição Fonêmica correlaciona-se mais fortemente com rotas de leitura fonológica e lexical. De fato, a correlação com os subtestes logográficos foi não significativa, ou foi menos significativa que com subtestes fonêmicos (Transposição e Subtração Fonêmicas, e Trocadilho). Assim, o desenvolvimento de habilidades metalinguísticas no nível fonêmico (Transposição e Subtração Fonêmica e Trocadilhos) associa-se ao desenvolvimento de mais eficientes habilidades de leitura (inicialmente pela rota fonológica de decodificação grafema-fonema, convertendo grafemas em fonemas para compreender a escrita, e subsequentemente, pela rota lexical de reconhecimento visual direto das formas ortográficas, que, por sua vez, está associado com o desenvolvimento de mais eficientes habilidades de leitura orofacial (converter optolalemas em fonemas para compreender a fala lida nos lábios). Subtestes logográficos (de pré-leitura) não predizem confiavelmente nem bom nível de habilidade metafonológica nem bom nível de leitura orofacial (conversão de optolalemas em fonemas). Dados apoiam a interpretação de que a leitura orofacial (conversão de optolalemas em fonemas) depende de leitura alfabética que, por sua vez, depende de habilidades metafonológicas. Foram normatizados oito testes, e cinco subtestes de leitura, e nove subtestes de consciência fonológica. Na Parte 2, 154 alunos (61 do Ensino Superior e 93 do Ensino Fundamental) foram submetidos a uma prova de escrita sob ditado de 560 palavras de baixa frequência de ocorrência. Anovas revelaram que a precisão da cifragem das palavras ouvidas foi função positiva da média aritmética dos índices de cifrabilidade das relações fonografêmicas componentes dessas palavras, conforme modelo de Capovilla. Análise de erros de escrita (paragrafias) indicam efeito de leitura orofacial visual, pois os grafemas produzidos nas paragrafias mapearam mais concentradamente os fonemas dos mesmos pontos de articulação daqueles componentes das palavras ouvidas / The dissertation is divided into two parts. Part 1 assessed the relationships holding among alphabetical reading, speech reading, auditory vocabulary, phonological awareness, recognition memory, and sentence reading comprehension in a sample of 157 children aged 6- 8 years. Part 2 assessed writing under dictation: error analyses based on cyphering precision measures and phonetics underlying speech reading (articulation points of the phonemes corresponding to the writing errors) in 154 college and elementary school students.Part 1 used the following tests: Speech Reading Skill Test (SRST), Computerized Speech Reading Vocabulary Test (CSRVT), Alphabetic Reading Skill (Word Decoding-Recognition) Test (ARST); Auditory Vocabulary (AVT), Phonological Awareness Test (PAT), Computerized Picture Recognition Memory Test (CPRMT-112), Computerized Image Recognition Memory Test (CIRMT-180), Reading Comprehension Skill Test, Alphabetic Reading Skill (Word Decoding-Recognition) Test (ARST). Results showed that: 1) The orthographic lexicon (subtest of rejecting Homophone Pseudo-words) increased systematically in a monotonic way from kindergarten to 1st grade to 2nd grade; 2) Speech-reading skill is most strongly associated with the alphabetic reading skill; 3) Reading subtests that demand phonological reading strategy and lexical reading strategy were directly proportional to meta-phonological skills subtests, specially those at the phonemic level; 4) Subtests that demand phonological reading strategy were strongly associated with speech-reading tests. The greater the skill of converting graphemes into phonemes, the greater the skill of converting optolalemes into phonemes in order to comprehend speech via lip-reading. 5) Speech-reading skill was most strongly correlated with the meta-phonological skills of Phonemic Transposition and Addition. Thus, meta-phonological skills at the phonemic level seemed to foster speech-reading skill. Phonemic Transposition skill was most strongly correlated with phonological and lexical reading strategies. Alphabetic Reading Test subtests that demanded just basic logographic strategy were not correlated or were only very weakly correlated with Phonological Awareness Test subtests that demand high phonemic processing. There was a positive correlation between phonemic skills on one hand and, on the other hand, phonological reading skills and lexical reading skills. Also, there was a positive correlation between phonological and lexical reading skills on one hand and speech-reading skills on the other hand. Alphabetic Reading Skill Test subtests that require only a basic logographic reading strategydo not predict reliably neither meta-phonological skills, nor speech-reading skills. Such data give support to the interpretation that the speech-reading skill of converting optolalemes into phonemes relies on the alphabetic reading skills. In turn, such alphabetic reading skills rely on meta-phonological skills. In Part 2, 154 participants (61 college students and 93 elementary school students) were assessed in a spelling under auditory dictation test of 560 extremely rare words. ANOVAS revealed that the encoding precision of the spoken words to be spelled under dictation was a positive function of the encoding index mean of the phoneme-grapheme relationships that make up those words, according to Capovillas model. Spelling error (paragraphia) analyses suggest visual speech reading effects in spelling under auditory dictation: The unconventional spelling units produced in the paragraphias matched the articulation points of the phonemes to be mapped

Introdução: A atividade muscular mastigatória rítmica (AMMR) é classificada como distúrbio de movimento estereotipado, caracterizada pelo ranger ou o apertar dos dentes durante o sono, também denominada bruxismo do sono (BS). A prática clínica sugere que o bruxismo seja um fator de risco para a dor orofacial e o cansaço muscular. Não existe tratamento definitivo para ele, mas sim medidas preventivas para evitar suas complicações, (dor orofacial, desgaste dental, zumbido, entre outras). Dispositivos intraorais são comumente utilizados no controle do bruxismo. Objetivos: O objetivo deste estudo foi avaliar a modulação do bruxismo do sono e da dor muscular mastigatória após 45 dias de uso de placas intraorais. Pacientes: 21 pacientes que relatavam sons de ranger de dentes durante o sono e também apresentavam dor muscular mastigatória; foram tratados com dispositivos intraorais (placa oclusal e não-oclusal) e divididos em 3 grupos: Grupo 1 (n=7) placa oclusal, Grupo 2 (n=7) placa não-oclusal e Grupo 3 (n=7) pacientes aguardando tratamento (grupo controle). Materiais e métodos: todos os pacientes foram submetidos à avaliação sistemática que constou de: 1-protocolo EDOF-HC; 2-Escala Visual Analógica; 3-RDC/TMD; 4-questionário específico do bruxismo do sono e 5- ortopantografia) e quatro noites de polissonografia (PSG), (noite de habituação, noite de diagnóstico, após 7dias e após 45 dias da utilização de dispositivos orais). ANOVA e o Teste Exato de Fischer foram usados para análise estatística. Resultados: Após 45 dias de avaliação houve redução da dor dos pacientes que utilizaram placa oclusal e não oclusal (Grupo 1 p=0,001, Grupo 2 p=0,001) quando comparada à noite inicial, entretanto, todos os pacientes do Grupo 3 continuaram com dor orofacial e cansaço muscular. Com exceção do tempo de estágio do sono REM, não houve diferenças estatísticas significantes nas variáveis do sono obtidas pela avaliação das PSG de todos os pacientes. O número de AMMR aumentou no Grupo1 (p=0,002), comparado ao Grupo 3 (p=0,900), entre a avaliação inicial e após 45 dias. Conclusão: A dor muscular mastigtatória foi reduzida nos grupos que utilizaram as placa oclusal e nãooclusal quando comparados àqueles que não a utilizaram, após 45 dias. Foi observado um aumento estatisticamente significante no número de atividade muscular mastigatória rítmica nas polissonografias dos pacientes que utilizaram placa oclusal. O mecanismo que sugere esse aumento é a redução da dor muscular mastigatória / Introduction: The rhythmic masticatory miofascial activity (RMMA) is classified as a mandibular movement disorder characterized by jaw clenching and tooth grinding during sleep so called sleep bruxism. Clinical practice sugests that bruxism is a risk factor of pain and muscular fatigue. There is no definitive treatment but certain preventive measures to avoid complications (orofacial pain, ringing in ears, tooth wear, and others). Intraoral devices are commonly used for bruxism and pain control. Objectives: The purpose of the present study was to evaluate the modulation of rhythmic masticatory mandibular activity (RMMA) and temporomandibular disorder pain (TMDP) of patients after 45 consecutive days of use of an intraoral device. Patients: 21 patients with TMDP and reported tooth grinding sounds during sleep and pain were randomized and divided into the following 3 groups: Group 1 (n=7) intraoral splint, Group 2 (n=7) palatal splint, and Group 3 (n=7) patients awaiting treatment. Methods: All patients were submitted to an interview, a systematic evaluation (EDOF-HC protocol, Visual Analogic Scale, RDC/TMD, orthopanthomography) and three PSG (baseline, 7days, and 45 days after treatment onset). ANOVA and Chi- Square tests were used for statistical analyses. Results: At 45th -day evaluation, TMDP reduced (Group A, p=0.001; Group B, p=0.001) when compared to baseline; Group 1 and Group 2 were free from pain after 45 days. On the other hand, all patients in Group 3 continued with TMDP and muscle fatigue. There were differences between groups in REM sleep data obtained by PSG evaluations, and the number of RMMA increased in Group 1 (p=0.002) compared to Group 3 (p=0.900) between baseline and 45th -day evaluation. Conclusions: TMDP was reduced in the groups that used intraoral and palatal splints when compared to non-users after 45 days; there were no changes in sleep parameters, and therefore there was an increase in the number of RMMA as shown by PSG studies among the patients that used intraoral splints. The suggested mechanism for that increase is the reduction of TMDP

Non-syndromic orofacial clefting (nsOFC) is among the most common congenital birth defects occurring up to 1 in 800 live births, with genetic and environmental causes. Genome wide association studies (GWAS) have identified several genetic loci that confer risk for nsOFC. However, more than half the heritable risk for nsOFC remains unknown and is considered ‘missing’. Moreover, continued sequencing of nsOFC patient DNA by whole exome sequencing and whole exome sequencing identify hundreds of single nucleotide polymorphism (SNPs). The identification of causal SNPs, however, continues to be a challenge in the OFC community. This is fueled partly by a lack of understanding of: (i) molecular mechanism and, (i) the gene regulatory network (GRN) governing differentiation of the relevant tissue, the embryonic superficial epithelia, also known as the periderm. Research has demonstrated that aberrant differentiation of the periderm, particularly the oral periderm results in pathological adhesions of surfaces within the developing oral cavity resulting in OFC. Further these adhesions can extend to the limbs which is a hallmarks feature in some forms of syndromic OFC (sOFC). In zebrafish, our model system of choice, knock-out of interferon regulatory factor 6 (irf6) ablated periderm marker expression and subsequently induces early embryonic lethality. The ortholog of IRF6 is a major genetic locus of Van der Woude syndrome (VWS) the most common form of sOFC and variants of IRF6 elevate risk for nsOFC. Therefore, we hypothesize that GRN of zebrafish periderm differentiation under the control of irf6 is a tool that can be used to identify novel OFC loci. Supporting this view, we have recently demonstrated that knock-down of an irf6 dependent gene encoding transcription factor Grainy-head like 3 (Grhl3) results in aberrant zebrafish periderm differentiation and GRHL3 was recently discovered as a novel VWS genetic locus. Hence it is likely that orthologs of genes encoding additional members of the periderm GRN harbor mutations in OFC patients. To identify cis–regulatory and transcriptional components in the periderm GRN, we performed: (i) a screen for periderm enhancers through in vivo green fluorescent protein (GFP) reporter assays, and, (ii) irf6 RNA-seq, followed by irf6 ChIP-seq to identify direct targets. From our screen for cis-regulatory elements we have identified a candidate human ZNF750 enhancer that directs GFP reporter expression in the zebrafish periderm. From our screen for irf6 direct targets we have identified several transcription factors including klf17, tfap2a and grhl3, all of which have variants in the human orthologs found in OFC patients. We further resolve the structure of the periderm differentiation GRN in zebrafish by assessing loss of function profiles for klf17, tfap2a and grhl3. Additionally, among the irf6 direct targets is a gene encoding another transcription factor, Zinc finger protein 750 (Znf750). We provide evidence to show that znf750 is expressed weakly in the zebrafish periderm. Further, we sequenced DNA in 500 nsOFC patient samples and identify a novel missense Ser160Pro ZNF750 variant which phenocopies the early embryonic lethality observed in irf6 mutants. Therefore, investigation of the zebrafish periderm GRN structure has facilitated the identification of OFC-associated risk loci.

<p>Orofaciala funktioner såsom mimik, tal, tuggning och sväljning är viktiga för livskvaliteten. Det råder generell brist på normerade test som bedömer dessa funktioner och därför har Nordiskt Orofacialt Test – Screening (NOT-S) utvecklats. Syftet med föreliggande studie var att normera NOT-S för barn med typisk utveckling i åldrarna 3:0-6:0 år. Testet består av en strukturerad intervjudel och en undersökningsdel med sex avsnitt vardera. Kalibrering utfördes innan testningen inleddes och visade på hög inter- och intrabedömaröverensstämmelse (94% respektive 96-99%). Det var 132 barn, 62 pojkar och 70 flickor, som deltog i testningen vilken utfördes på barnens förskolor. Resultatet visade att barn med typisk utveckling i åldersgruppen 3:0-3:11 år kan förväntas få en totalpoäng på 1,41 ± 0,96, barn i åldersgruppen 4:0-4:11 år en totalpoäng på 1,31 ± 1,04 samt barn i åldersgruppen 5:0-6:0 år en totalpoäng på 1,41 ± 0,94. Det fanns inga generella signifikanta ålders- eller könsskillnader. Signifikanta skillnader återfanns på enstaka frågor och uppgifter inom avsnitten Dregling (V), Näsandning (2) och Oral motorik (5). Sammanfattningsvis kan konstateras att NOT-S är ett lättadministrerat orofacialt test som med tillägg av denna normering har potential att bli ett välanvänt screeningmaterial för yrkesgrupper involverade vid bedömning av barns orofaciala funktion.</p> / <p>Orofacial functions, such as nutrition, speech and facial expression, are essential for the quality of life. Due to the lack of standardized tests regarding these functions the Nordic Orofacial Test – Screening (NOT-S) was developed. The aim of this study was to collect norm data for NOT-S for children with typical development aged 3:0-6:0 years. The test consists of a structured interview and a clinical examination with six domains each. Calibration performed before testing, showed high inter- and intraexaminer agreement (94% and 96-99% respectively). Totally 132 children, 62 boys and 70 girls, were tested at their preschools. Findings showed that children aged 3:0-3:11 years can be expected a mean score of 1,41 ± 0,96; children aged 4:0-4:11 years a mean score of 1,31 ± 1,04 and children aged 5:0-6:0 a mean score of 1,41 ± 0,94. There were no general statistically significant differences regarding age or gender. Statistically significant differences were found regarding a few questions and tasks within the domains Drooling (V), Nose breathing (2) and Oral motor function (5). In conclusion, NOT-S is an easy administered orofacial test that has, with the addition of this norm data for children, the potential of becoming a widely used test.</p>

L'évaluation, le diagnostic et le traitement des douleurs et des dysfonctionnements de l'appareil stomatognathique, encore appelés « Syndrome algo-dysfonctionnel de l'appareil manducateur », ont évolué dans leur approche clinique. En fonction du choix des organes observés, de l'appréciation du rôle respectif des différents facteurs déclenchant ou entretenant la pathologie et en considérant l'étiopathogénie de ces désordres, de nombreuses propositions de dénomination se sont succédées au fil des années. Il s'agit maintenant de dysfonctions cranio mandibulaires ou de désordres temporo mandibulaires (DTM) qui prennent plus en considération les causes extérieures à la sphère oro faciale. Les désordres temporo-mandibulaires sont reconnus comme une cause majeure de douleurs oro-faciales non dentaire et représentent une classe de désordres musculo-squelettiques. La recherche conduit à considérer les DTM comme un ensemble corrélé de symptômes affectant l'appareil manducateur. De toute évidence, les signes et symptômes rencontrés lors de l'analyse des patients présentant des algies ou des dysfonctionnements de l'appareil manducateur, même s'ils intéressent un territoire bien délimité, ne peuvent pas être placés dans une urne commune. Ainsi, conformément à la conception moderne d'une étiologie multifactorielle, les désordres temporo-mandibulaires revêtent, par leurs manifestations cliniques, une sémiologie très polymorphe. Les patients consultent pour des douleurs exquises ou diffuses de la mâchoire rebelles à toute thérapeutique médicale, pour des bruits au niveau de l'articulation temporo mandibulaire, pour une gêne lors des mouvements mandibulaires mais également pour des céphalées, des otalgies et des algies cranio-cervico-faciales. De plus, la multiplicité des signes objectifs et subjectifs peut constituer un véritable dédale dans lequel un diagnostic précis s'avère délicat. Les neurophysiologistes reconnaissent que plus un appareil ou un système est important, plus son complexe sensitif apparaît hautement différencié. Ainsi, l'appareil manducateur, par le biais des nerfs trijumeaux, bénéficie d'une innervation sensitive particulièrement riche. En effet, l'arcade dentaire mandibulaire entre en contact avec son arcade dentaire antagoniste dans un très grand nombre de positions dont certaines sont très particulières. L'incision, la mastication, la déglutition, la respiration, la phonation et la mimique font largement appel à la mobilisation de la mandibule. Cette polyvalence fonctionnelle repose sur plusieurs mécanismes neurophysiologiques. Le sens de la proprioception, alimenté par les capteurs musculaires, articulaires, tendineux, parodontaux, muqueux, informe sur la position mandibulaire et sur les forces musculaires exercées. Il permet d'ajuster les mouvements, de les coordonner pour remplir au mieux ces fonctions. Enfin, la capsule de l'articulation temporo-mandibulaire (ATM) est particulièrement riche en récepteurs proprioceptifs pour améliorer la discrimination des situations et des postures. Une régulation harmonieuse de cet appareil requiert des informations périphériques et centrales correctes ; en l'absence de celles-ci, des troubles et des douleurs peuvent apparaître. Vu la complexité des connexions du nerf trijumeau, il est tout à fait justifié de penser que des perturbations dans le système afférent, en provenance des muscles, des tendons, des articulations et des dents, peuvent entraîner des dysfonctions des circuits neuronaux. De plus, on sait que toute fonction physiologique requiert l'étude exhaustive de deux aspects, l'un sensitif, l'autre moteur. Les patients atteints de DTM présentent une altération du système neuromusculaire. Cette conception est admise par Nielsen dans une étude soulignant l'intérêt de l'Electromyographie (EMG) dans les troubles oro-faciaux. Certains auteurs se sont attachés à étudier d'autres techniques d'exploration neurophysiologique que l'EMG tels que les potentiels évoqués moteurs et somesthésiques, le réflexe de clignement ou encore la suppression extéroceptive du muscle temporal (EST). Nous avons étudié une de ces explorations neurophysiologiques dans le cadre de quelques pathologies oro-faciales et principalement les désordres temporo-mandibulaires : l'examen de la suppression extéroceptive du muscle temporal (EST). Dans notre recherche, nous avons pour objectif d'effectuer dans un premier temps une synthèse et une évaluation de la littérature sur l'EST. Dans un second temps, nous avons évalué la technique de la suppression extéroceptive en mettant en place une méthodologie originale d'enregistrement. Nous avons examiné la reproductibilité de cette méthodologie au sein d'une population de sujets sains. Dans un troisième temps, nous avons évalué la technique de la suppression extéroceptive, dans une étude prospective randomisée en double aveugle, sur une population de sujets présentant des désordres temporo-mandibulaires. Enfin, nous avons évalué la technique de la suppression extéroceptive, dans une étude rétrospective sur des sujets présentant des désordres temporo-mandibulaires et différents troubles oro-faciaux. / The Aim of this study is the development of an exteroceptive suppression evaluation program (ESEP), wich uses the exteroceptive suppression of temporalis (EST) as complementary examination to diagnose temporomandibular disorders (TMD). The subjects, responding to different inclusion and exclusion criteria, undergo 6 tests EST where various procedures are carried out: reversible modification of the dental occlusion, ultrasounds application on the neck and structured cervical mobilizations. The measured parameters are the latencies and durations of ES1 and ES2 in various degrees of suppression. The EST of healthy group is different from pathological group. The parameters are reproducible in the two groups. The reversible modification of dental occlusion and the structured cervical mobilization change in a highly significant way the parameters of ES2 in marked degrees of suppression. EST remains perfectly reproducible. The installation of ESEP, makes it possible to qualify and quantify the results.

Orofaciala funktioner såsom mimik, tal, tuggning och sväljning är viktiga för livskvaliteten. Det råder generell brist på normerade test som bedömer dessa funktioner och därför har Nordiskt Orofacialt Test – Screening (NOT-S) utvecklats. Syftet med föreliggande studie var att normera NOT-S för barn med typisk utveckling i åldrarna 3:0-6:0 år. Testet består av en strukturerad intervjudel och en undersökningsdel med sex avsnitt vardera. Kalibrering utfördes innan testningen inleddes och visade på hög inter- och intrabedömaröverensstämmelse (94% respektive 96-99%). Det var 132 barn, 62 pojkar och 70 flickor, som deltog i testningen vilken utfördes på barnens förskolor. Resultatet visade att barn med typisk utveckling i åldersgruppen 3:0-3:11 år kan förväntas få en totalpoäng på 1,41 ± 0,96, barn i åldersgruppen 4:0-4:11 år en totalpoäng på 1,31 ± 1,04 samt barn i åldersgruppen 5:0-6:0 år en totalpoäng på 1,41 ± 0,94. Det fanns inga generella signifikanta ålders- eller könsskillnader. Signifikanta skillnader återfanns på enstaka frågor och uppgifter inom avsnitten Dregling (V), Näsandning (2) och Oral motorik (5). Sammanfattningsvis kan konstateras att NOT-S är ett lättadministrerat orofacialt test som med tillägg av denna normering har potential att bli ett välanvänt screeningmaterial för yrkesgrupper involverade vid bedömning av barns orofaciala funktion. / Orofacial functions, such as nutrition, speech and facial expression, are essential for the quality of life. Due to the lack of standardized tests regarding these functions the Nordic Orofacial Test – Screening (NOT-S) was developed. The aim of this study was to collect norm data for NOT-S for children with typical development aged 3:0-6:0 years. The test consists of a structured interview and a clinical examination with six domains each. Calibration performed before testing, showed high inter- and intraexaminer agreement (94% and 96-99% respectively). Totally 132 children, 62 boys and 70 girls, were tested at their preschools. Findings showed that children aged 3:0-3:11 years can be expected a mean score of 1,41 ± 0,96; children aged 4:0-4:11 years a mean score of 1,31 ± 1,04 and children aged 5:0-6:0 a mean score of 1,41 ± 0,94. There were no general statistically significant differences regarding age or gender. Statistically significant differences were found regarding a few questions and tasks within the domains Drooling (V), Nose breathing (2) and Oral motor function (5). In conclusion, NOT-S is an easy administered orofacial test that has, with the addition of this norm data for children, the potential of becoming a widely used test.

The general aim of this thesis was to broaden our knowledge of the signs and symptoms, genetics, and outcomes of dental implant treatment in individuals with oligodontia or ectodermal dysplasia. Article I is a population-based study in three Swedish counties of 162 individuals with oligodontia, which was a prevalence of 0.09%. The intent was to explore ways for dentists to assess symptoms from other ectodermal structures than teeth through a clinical interview and chair-side analyses. Thirty per cent had low salivary secretion rates while only 11% with no known syndrome reported symptoms from hair, nails, or sweat glands. These are, together with teeth, the ectodermal structures on which it is proposed that a clinical diagnosis of ectodermal dysplasia (ED) be based. Article II screened 93 probands with oligodontia for mutations in six genes known to cause oligodontia and hypohidrotic ED. Sequence alterations predicted to be damaging or potentially damaging were revealed in the AXIN2, MSX1, PAX9, and EDARADD genes in 14 (15%) of the probands. All mutations but one were novel. For the first time, EDARADD mutations were shown to cause isolated oligodontia. No individual who had reported ectodermal symptoms from hair, nails, or sweat glands had a mutation. Article III assessed orofacial function in individuals with different types of EDs using the Nordic Orofacial Test-Screening (NOT-S) protocol. Individuals with ED scored significantly higher in orofacial dysfunction than a healthy reference sample, especially in the Chewing and swallowing, Dryness of the mouth, and Speech domains. Article IV surveyed treatment outcome of dental implants in Swedish children up to age 16 years. In a 20-year period, only 26 patients were treated, 5 of whom had hypohidrotic ED and anodontia of the mandible. Individuals with ED had 64% failed implants compared to 6% among subjects with teeth missing due to trauma or agenesis. The main conclusions of this thesis were that (i) a check of whether one or more permanent incisors are missing will identify 65% of individuals with oligodontia and 84% of individuals missing nine teeth or more, (ii) evaluation of salivary secretion is indicated in children with oligodontia, (iii) a majority of individuals with oligodontia did not report other abnormal ectodermal organ function besides teeth, (iv) no clinical indicator discriminated between individuals with and without mutations in the tested genes, and more unidentified genes are involved in tooth morphogenesis, (v) EDARADD mutations are associated with isolated oligodontia, (vi) evaluation of orofacial function is indicated in individuals with ED, and many individuals with ED would benefit from orofacial skills training, (vii) dental implant placement is a rare treatment modality in children, (viii) individuals with hypohidrotic ED seem to present special challenges due to structural as well as direct effects of the mutations on bone, which seem to compromise osseointegration, (ix) central registers on signs and symptoms in individuals with rare disorders would help establish prevalences of various diagnoses and define treatment needs, and (x) quality registers for monitoring treatment outcomes of dental implants would promote early detection of risks and side-effects in individuals with rare disorders.