The purpose of this cross-sectional study was to determine whether patients exhibiting third molar agenesis also exhibit delayed development and/or eruption of the adjacent second molar. The initial panoramic radiographs of 739 patients, 13-17 years of age, from the University of Iowa's Department of Orthodontics were examined. The developmental stage of each second molar according to Demirjian's 8-stage classification system, the eruption stage of each second molar, along with the presence or absence of each third molar were recorded, and Pearson chi-squared tests were used to determine differences in developmental and eruptive timing between those missing third molars and those with third molars present. We conclude that patients missing their maxillary third molars exhibit delayed development of the adjacent maxillary second molars. In addition, patients missing any of their four third molars exhibit delayed eruption of their adjacent second molars. The findings also suggest that mandibular second molars develop later than, but erupt earlier than, maxillary second molars.

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.

Made available in DSpace on 2015-05-14T12:56:08Z (GMT). No. of bitstreams: 1 parte1.pdf: 1574807 bytes, checksum: 13d40098a55f04ebaed60e9412af63c9 (MD5) Previous issue date: 2010-01-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to ascertain the influence of dental agenesis in cephalometric pattern in patients residing in the city of João Pessoa / PB, in the year 2009. The sample consisted of 52 patients with congenital absence of one or more teeth (excluding third molars) of both sexes in mixed dentition (group 1, n = 29 patients, aged 8 to 12 years, mean 9.93 ± 1.43 years) and permanent dentition (group 2, n = 23 patients, aged 13 to 18 years, mean 14.63 ± 1.82 years). The data collection covered the diagnosis of tooth agenesis by observing panoramic radiographs and clinical records, and getting in cephalometric lateral radiographs. Were taken twenty cephalometric skeletal and dental nine from cephalograms obtained Cef X ® software (version 2.4). A cross-sectional analysis enabled comparison of the cephalometric pattern of patients with dental agenesis (Groups 1 and 2) the pattern of Brazil, proposed by Martin et al. (1998) - (control group 1 and 2), respectively. Patients with tooth abnormalities were divided into subgroups according to the region of impact (front and back) and hit by absences arch (maxilla and mandible). Data were analyzed using SPSS version 13.0 (Statistical Package for Social Sciences), performing frequency distributions, descriptive measures of achievement for all variables, and statistical tests of comparisons between groups (t test Student's unpaired). The missing teeth more frequently observed in patients in group 1 (mixed dentition), involving the upper lateral incisors (46.3%) and second mandibular premolars (18.5%) patients in group 2 (permanent dentition) the second pre-molars (54.5%) and lateral incisors (18.2%) were most frequently involved. Compared to standard cephalometric Brazilians, patients with dental agenesis in both groups showed significant changes in vertical and horizontal dimension, demonstrated by the reduced length of the jaws, the anterior cranial base and anterior inferior facial height, whereas only in group 2 was observed, mandibular retrusion and significant dental changes associated with tooth agenesis involving the lower arch, were presented. Although it was observed that the tooth abnormalities did not influence the pattern of facial growth in patients in this study, in designing the treatment plan, the orthodontist should consider that the craniofacial dimensions and the relationship interarch, these patients may be changed, in addition to the variations associated with age. / Este estudo teve como objetivo verificar a influência das agenesias dentárias no padrão cefalométrico em pacientes residentes na cidade de João Pessoa/PB, no ano de 2009. A amostra constou de 52 pacientes com ausências congênitas de um ou mais dentes (excluindo terceiros molares), de ambos os gêneros, em fase de dentadura mista (grupo 1, n=29 pacientes, na faixa etária de 8 a 12 anos, média de 9,93 ± 1,43 anos) e dentição permanente (grupo 2, n=23 pacientes, na faixa etária de 13 a 18 anos, média de 14,63 ± 1,82 anos). A coleta de dados abrangeu o diagnóstico da agenesia dentária por meio da observação de radiografias panorâmicas e fichas clínicas, e a obtenção do padrão cefalométrico em telerradiografias em norma lateral. Foram tomadas 20 grandezas cefalométricas esqueléticas e 9 dentárias a partir de cefalogramas obtidos no software Cef X® (versão 2.4). A análise transversal permitiu a comparação do padrão cefalométrico dos pacientes com agenesias dentárias (Grupos 1 e 2) ao padrão de brasileiros, proposto por Martins et al., (1998) (Grupos-controles 1 e 2), respectivamente. Os pacientes com agenesias dentárias foram divididos em subgrupos de acordo com a região de incidência (anterior e posterior) e arco dentário atingido pelas ausências (maxila e mandíbula). Os dados foram analisados através do programa estatístico SPSS versão 13.0 (Statistical Package for the Social Sciences), realizando-se distribuições de freqüências, obtenção das medidas descritivas para todas as variáveis, assim como testes estatísticos de comparações entre os grupos (teste t de Student, não pareado). As ausências dentárias mais freqüentes observados nos pacientes do grupo 1 (dentadura mista), envolveram os incisivos laterais superiores (46,3%) e segundos pré-molares inferiores (18,5%), nos pacientes do grupo 2 (dentição permanente), os segundos pré-molares inferiores (54,5%) e incisivos laterais superiores (18,2%), foram os mais envolvidos. Comparado ao padrão cefalométrico de brasileiros, os pacientes com agenesias dentárias, em ambos os grupos apresentaram alterações significativas na dimensão vertical e horizontal, demonstrado pelo reduzido comprimento dos maxilares, da base craniana anterior e da altura facial ântero-inferior, enquanto que apenas no grupo 2 observou-se, retrusão mandibular e alterações dentárias significativas, associadas à agenesias dentárias envolvendo o arco dentário inferior, foram apresentadas. Embora se tenha observado que as agenesias dentárias não influenciaram o padrão de crescimento facial nos pacientes do presente estudo, ao conceber o plano de tratamento, o ortodontista deve considerar que as dimensões craniofaciais e o relacionamento interarcos, nestes pacientes podem estar alterados, para além das variações associadas à idade.

A agenesia dentária é a falha do desenvolvimento do germe dentário causando a ausência definitiva do dente. Constitui–se na anomalia dentária mais comum, afetando até um quarto da população em geral. A principal causa está relacionada com a função anormal de genes específicos que desempenham um papel chave durante a odontogênese, especialmente o MSX1 e o PAX9. Apesar da alta frequência dessa anomalia, apenas algumas mutações no MSX1 e no PAX9 foram associadas com a agenesia não–sindrômica até o momento. Uma vez que um número maior de indivíduos afetados é esperado nos próximos anos, uma análise mais profunda dos defeitos genéticos que levam à agenesia torna–se fundamental. O objetivo desta pesquisa foi estudar seis famílias segregando oligodontia/hipodontia não–sindrômica, além de investigar a presença de mutações nos genes MSX1 e PAX9 com a finalidade de associar fenótipo e genótipo. As famílias, que apresentam mais de um integrante com agenesia, foram selecionadas a partir de uma clínica particular. Amostras de células epiteliais bucais foram coletadas de todos os indivíduos por meio de escovas citológicas. O DNA foi isolado, amplificado e sequenciado. Todas as sequências foram comparadas com as existentes no GenBank. A homologia das sequências mutantes também foi comparada utilizando–se o software online BLAST. Os genes MSX1 e PAX9 de dez indivíduos controle não afetados e sem grau de parentesco também foram sequenciados. Foi identificada uma nova mutação missense no exon 2 próximo ao final do domínio pareado do PAX9 em três famílias. A mutação heterozigótica C503G resulta em uma troca de aminoácido de alanina para glicina no resíduo 168 (Ala168Gly), o qual é invariavelmente conservado entre várias espécies. A mudança alanina–glicina pode determinar uma alteração da estrutura proteica devido às propriedades únicas de flexibilidade da glicina, levando à agenesia dentária. Tal mutação não encontra–se registrada em nenhum banco de dados conhecido ou na literatura sendo, portanto, inédita. As mutações intrônicas IVS2–109G>C, IVS2–54A>G e IVS2–41A>G também foram identificadas no PAX9. Essas variantes polimórficas podem estar envolvidas no fenótipo uma vez que um probando, o qual apresentou todas as três mutações intrônicas em homozigose, foi afetado com a mais severa forma de oligodontia dentro da amostra. A transição * 6C>T foi identificada no exon 2 do MSX1, em apenas uma família. Devido ao fato de estar localizada seis bases após o stop codon, essa mutação homozigótica pode dificultar/alterar o término da tradução contribuindo, assim, para o fenótipo. Novos estudos acerca da expressão gênica em um número maior de famílias afetadas irá aumentar o conhecimento sobre agenesia dentária. Tal entendimento permitirá alcançar melhores opções de tratamento e, talvez, uma ferramenta de diagnóstico precoce que, possivelmente, envolverá o exame de DNA baseado em variantes polimórficas. Todos esses dados podem auxiliar a clínica odontológica em um futuro próximo. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-17T14:28:55Z No. of bitstreams: 1 Tese Breno Ramos Boeira Junior.pdf: 3106508 bytes, checksum: d974027dc18150cfe6e3bc0b2ba8edb1 (MD5) / Made available in DSpace on 2014-06-17T14:28:55Z (GMT). No. of bitstreams: 1 Tese Breno Ramos Boeira Junior.pdf: 3106508 bytes, checksum: d974027dc18150cfe6e3bc0b2ba8edb1 (MD5) / Universidade de Caxias do Sul / Tooth agenesis, the failure of development of tooth bud causing definitive absence of the tooth, is the most common dental anomaly affecting up to one quarter of the general population. The main cause is related to abnormal function of specific genes which play key roles during odontogenesis, particularly MSX1 and PAX9. Despite the high frequency of this anomaly, there are only a restricted number of mutations in MSX1 and PAX9 that have been associated with non–syndromic tooth agenesis so far. Since a greater number of affected subjects is expected over the coming years, a deeper analysis of the gene networks underlying tooth agenesis is critical. The aim of this research was to investigate six families segregating non–syndromic oligodontia/hypodontia as well as to screen for mutations in their MSX1 and PAX9 genes, attempting to associate phenotype and genotype. Families were selected from a private office. They should present more than one relative affected with agenesis. All subjects had a sample of buccal epithelial cells collected with cytology brushes. DNA was isolated, amplificated and sequenced. All sequences were compared to those in GenBank. Homology of the mutant sequences was also compared using BLAST online software. MSX1 and PAX9 genes from ten unrelated unaffected control subjects were also sequenced. A novel missense mutation lying in the exon 2 close to the end of the paired domain of PAX9 was identified in three families. Heterozygous mutation C503G is expected to result in an alanine–to–glycine amino acid change in residue 168 (Ala168Gly), which is invariably conserved among several species. The alanine–glycine change might lead to protein structural alteration due to the unique flexibility properties of glycine, leading to tooth agenesis. This is a novel mutation since it is not registered neither in any known database nor in literature. Intronic mutations IVS2–109G>C, IVS2–54A>G and IVS2–41A>G were also identified in PAX9. These polymorphic variants may be involved in the phenotype as one proband, showing all three intronic mutations in homozygosis, was affected with the most severe oligodontia within the sample. Transition *6C>T lying in the exon 2 six base pairs after the stop codon was detected in MSX1 gene in one family. Due to its proximity to the stop codon, this homozygous mutation can hinder a regular translation termination thus contributing to the phenotype. Further studies with gene expression in larger affected families will increase knowledge of tooth agenesis. Such understanding will allow to achieve better treatment options and, perhaps, an early diagnosis tool which would possibly lie on the DNA examination based on polymorphic variants. All this data may assist dental practice in a near future.

A agenesia dentária é a falha do desenvolvimento do germe dentário causando a ausência definitiva do dente. Constitui–se na anomalia dentária mais comum, afetando até um quarto da população em geral. A principal causa está relacionada com a função anormal de genes específicos que desempenham um papel chave durante a odontogênese, especialmente o MSX1 e o PAX9. Apesar da alta frequência dessa anomalia, apenas algumas mutações no MSX1 e no PAX9 foram associadas com a agenesia não–sindrômica até o momento. Uma vez que um número maior de indivíduos afetados é esperado nos próximos anos, uma análise mais profunda dos defeitos genéticos que levam à agenesia torna–se fundamental. O objetivo desta pesquisa foi estudar seis famílias segregando oligodontia/hipodontia não–sindrômica, além de investigar a presença de mutações nos genes MSX1 e PAX9 com a finalidade de associar fenótipo e genótipo. As famílias, que apresentam mais de um integrante com agenesia, foram selecionadas a partir de uma clínica particular. Amostras de células epiteliais bucais foram coletadas de todos os indivíduos por meio de escovas citológicas. O DNA foi isolado, amplificado e sequenciado. Todas as sequências foram comparadas com as existentes no GenBank. A homologia das sequências mutantes também foi comparada utilizando–se o software online BLAST. Os genes MSX1 e PAX9 de dez indivíduos controle não afetados e sem grau de parentesco também foram sequenciados. Foi identificada uma nova mutação missense no exon 2 próximo ao final do domínio pareado do PAX9 em três famílias. A mutação heterozigótica C503G resulta em uma troca de aminoácido de alanina para glicina no resíduo 168 (Ala168Gly), o qual é invariavelmente conservado entre várias espécies. A mudança alanina–glicina pode determinar uma alteração da estrutura proteica devido às propriedades únicas de flexibilidade da glicina, levando à agenesia dentária. Tal mutação não encontra–se registrada em nenhum banco de dados conhecido ou na literatura sendo, portanto, inédita. As mutações intrônicas IVS2–109G>C, IVS2–54A>G e IVS2–41A>G também foram identificadas no PAX9. Essas variantes polimórficas podem estar envolvidas no fenótipo uma vez que um probando, o qual apresentou todas as três mutações intrônicas em homozigose, foi afetado com a mais severa forma de oligodontia dentro da amostra. A transição * 6C>T foi identificada no exon 2 do MSX1, em apenas uma família. Devido ao fato de estar localizada seis bases após o stop codon, essa mutação homozigótica pode dificultar/alterar o término da tradução contribuindo, assim, para o fenótipo. Novos estudos acerca da expressão gênica em um número maior de famílias afetadas irá aumentar o conhecimento sobre agenesia dentária. Tal entendimento permitirá alcançar melhores opções de tratamento e, talvez, uma ferramenta de diagnóstico precoce que, possivelmente, envolverá o exame de DNA baseado em variantes polimórficas. Todos esses dados podem auxiliar a clínica odontológica em um futuro próximo. / Universidade de Caxias do Sul / Tooth agenesis, the failure of development of tooth bud causing definitive absence of the tooth, is the most common dental anomaly affecting up to one quarter of the general population. The main cause is related to abnormal function of specific genes which play key roles during odontogenesis, particularly MSX1 and PAX9. Despite the high frequency of this anomaly, there are only a restricted number of mutations in MSX1 and PAX9 that have been associated with non–syndromic tooth agenesis so far. Since a greater number of affected subjects is expected over the coming years, a deeper analysis of the gene networks underlying tooth agenesis is critical. The aim of this research was to investigate six families segregating non–syndromic oligodontia/hypodontia as well as to screen for mutations in their MSX1 and PAX9 genes, attempting to associate phenotype and genotype. Families were selected from a private office. They should present more than one relative affected with agenesis. All subjects had a sample of buccal epithelial cells collected with cytology brushes. DNA was isolated, amplificated and sequenced. All sequences were compared to those in GenBank. Homology of the mutant sequences was also compared using BLAST online software. MSX1 and PAX9 genes from ten unrelated unaffected control subjects were also sequenced. A novel missense mutation lying in the exon 2 close to the end of the paired domain of PAX9 was identified in three families. Heterozygous mutation C503G is expected to result in an alanine–to–glycine amino acid change in residue 168 (Ala168Gly), which is invariably conserved among several species. The alanine–glycine change might lead to protein structural alteration due to the unique flexibility properties of glycine, leading to tooth agenesis. This is a novel mutation since it is not registered neither in any known database nor in literature. Intronic mutations IVS2–109G>C, IVS2–54A>G and IVS2–41A>G were also identified in PAX9. These polymorphic variants may be involved in the phenotype as one proband, showing all three intronic mutations in homozygosis, was affected with the most severe oligodontia within the sample. Transition *6C>T lying in the exon 2 six base pairs after the stop codon was detected in MSX1 gene in one family. Due to its proximity to the stop codon, this homozygous mutation can hinder a regular translation termination thus contributing to the phenotype. Further studies with gene expression in larger affected families will increase knowledge of tooth agenesis. Such understanding will allow to achieve better treatment options and, perhaps, an early diagnosis tool which would possibly lie on the DNA examination based on polymorphic variants. All this data may assist dental practice in a near future.

Plusieurs fonctions cognitives sont latéralisées dans le cerveau humain adulte. Nous avons étudié l’origine des asymétries fonctionnelles chez les nourrissons, en évaluant les substrats neuronaux de reconnaissance des visages et des traitements du langage imbriqués dans les réseaux visuels et auditifs, grâce à la neuroimagerie non invasive (EEG et l’IRM de diffusion). Pour cela, nous avons étudié le développement fonctionnel et structurel de ces deux systèmes cérébraux au cours des six premiers mois postnataux. Nous avons observé que la vitesse des réponses visuelles était liée à la maturation des faisceaux de fibres de la matière blanche conduisant ces réponses, plus que l’âge des bébés, alors que la vitesse des réponses auditives doit dépendre d’un réseau de faisceaux de fibres et de régions corticales plus vaste. Parallèlement, nous avons étudié la latéralisation de la reconnaissance des visages grâce à un paradigme de discrimination des visages présentés dans chaque hémichamp. Nous avons observé que seul l'hémisphère droit pouvait discriminer les visages et que les informations pertinentes étaient transférées entre les deux hémisphères. Pour cibler la latéralisation du traitement du langage, nous avons étudié les réponses à des stimuli de la parole présentés de manière monaurale. Une comparaison entre un groupe de nourrissons avec une agénésie du corps calleux et un groupe contrôle a montré que les réponses à ces stimuli étaient transférées de façon asymétrique via le corps calleux. Cette asymétrie, facilitée vers l’hémisphère gauche, intervient probablement dans la latéralisation précoce du réseau du langage. L’ensemble de ces études mettent bien en évidence le potentiel de la neuroimagerie pour étudier le développement du cerveau et ces asymétries précoces. / Several cognitive functions such as face and speech processing are lateralized in the adult human brain. The ontogeny of these functional asymmetries is yet poorly understood. We aimed to evaluate the neural substrates of face and speech processing, nested in the visual and auditory networks using non-invasive neuroimaging techniques in infants. First, we studied how the functional and structural characteristics of these two brain systems change over the first postnatal semester. With EEG, we showed age-related decreases in the latency of brain responses and demonstrated that the speed of early visual responses is related to the maturation of underlying white matter tracts conducting them, as assessed with diffusion MRI. For the auditory system, our results suggested that the speed of responses may rely on maturation of more pathways and cortical regions. In parallel, we studied face processing lateralization using a discrimination paradigm of faces presented in each hemifield and observed that only the right hemisphere was able to discriminate between faces. Further evidence also suggested a transfer of face-relevant information across hemispheres. To study speech processing lateralization, we used a paradigm with monaural presentation of speech stimuli. A comparison between typical infants and infants with callosal agenesis, suggested an asymmetric transfer of auditory information across hemispheres, facilitated toward the left hemisphere, that might contribute to the lateralization of language early on. This thesis highlights the potential of neuroimaging techniques for the study of brain’s structural and functional development and of hemispheric asymmetries early on.

No description available.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Made available in DSpace on 2016-08-03T16:30:59Z (GMT). No. of bitstreams: 1 SABRINA ROCHA RIBEIRO.pdf: 1398760 bytes, checksum: a6be3e289c3ef7a5a5b2cfa76b4e0008 (MD5) Previous issue date: 2011-12-07 / The objective of this retrospective study was evaluate the prevalence of anomalies in tooth position (palatal ectopic eruption of the maxillary canine, dental transposition, distal angulation of mandibular second premolars, mesial angulation of mandibular permanent second molar and infra-occlusion of deciduous molars), number (supernumerary teeth) and size (microdontia) in patients with permanent tooth agenesis, by comparing them with the rates expected for the general population; in addition, the hypothesis was tested that patients with agenesis of permanent teeth have increased prevalence of enamel hypoplasia. To that end, the sample of this study consisted of 351 patients with agenesis of at least one permanent tooth, ranging between 8 and 30 years of age and with full clinical records. The sample was collected by examining orthodontic records belonging to the archives of a professional institution of specialization in Orthodontics, a dental radiology clinic and private orthodontic practices. Study materials included panoramic and periapical view radiographs, plaster cast models, intra- and extraoral photographs and filled-out medical records. First, the reproducibility of evaluations was analyzed through the rate of concordance using the Kappa test, at a 95% confidence interval. The Chi-square test was used to compare the prevalence of agenesis and anomalies in the sample to the expected rates according to scientific literature, considering a 5% level of significance. The study also analyzed the degree of the associations using the odds ratio and the respective 95% confidence interval. The prevalence of dental agenesis in the sample, excluding third molars, was 88.6%. Of the 351 patients, 128 (36.4%) had agenesis in the maxillary arch, 108 (30.8%) in the mandibular arch, and 115 (32.8%) in both arches. A total of 52.4% had agenesis in the maxillary left hemiarch, 55.0% in the maxillary right hemiarch, 48.7% in the mandibular left hemiarch and 47.3% in the mandibular right hemiarch. With regard to the associated anomalies evaluated, 28.5% microdontia, 28.2% had enamel hipoplasia, 7.4% had palatal ectopic eruption of the canine, 6.6% had distal angulation, 4.3% infra-occlusion, 3,9% transposition of canine/premolar, 3.7% supernumerary teeth, 3.7% medial angulation, 0,6% transposition of incisive/canine, and, when compared to the general population, they were 96.1 times more likely to feature mesial angulation of the mandibular second molar; 34.6 times more likely to have distal angulation; 15,9 times more likely to show transposition of canine/premolar; 14,3 times more likely to show transposition of incisive/canine; 9 times more likely to show hipoplasia; 8,1 times more likely to show microdontia of the lateral incisor; 5,2 times more likely to have palatal ectopic eruption of the canine; and with regard to infra-occlusion, there was a lower likelihood than the general population. From the obtained results, a strong association was observed between agenesis of permanent teeth with significant dental anomalies. It was detected that permanent tooth agenesis showed an increased prevalence of enamel hypoplasia, and that agenesis and other associated anomalies are genetically interlinked. / O objetivo deste estudo retrospectivo foi avaliar a prevalência de anomalias de posição (irrupção ectópica de canino superior para palatino, transposição dental, distoangulação de segundos pré-molares inferiores, mesioangulação de segundo molar inferior permanente e infraoclusão de molares decíduos), de número (supranumerários) e de tamanho (microdontias) em pacientes com agenesias de dentes permanentes, comparando-as com as prevalências esperadas para a população em geral, além de testar a hipótese de que pacientes com agenesia de dentes permanentes apresentem uma prevalência aumentada de hipoplasia de esmalte. Para tanto, a amostra deste estudo foi composta por 351 pacientes, com a presença de agenesia de no mínimo um dente permanente, na faixa etária entre 8 e 30 anos e com prontuários clínicos preenchidos. A amostra foi coletada a partir do exame das documentações ortodônticas pertencentes aos arquivos de uma escola de aperfeiçoamento profissional em Ortodontia, de uma clínica radiológica odontológica e de consultórios particulares de ortodontistas. O material de estudo englobou radiografias panorâmicas e periapicais, modelos de gesso, fotografias intra e extraorais e prontuários clínicos devidamente preenchidos. Inicialmente foi analisada a reprodutibilidade das avaliações pela porcentagem de concordância utilizando Kappa, com intervalo de confiança de 95%. O teste de qui-quadrado foi utilizado para comparar as prevalências de agenesias e anomalias na amostra com as prevalências esperadas segundo a literatura científica, considerando o nível de significância de 5%. Analisou-se, ainda, o grau das associações pela razão de chances ( odds ratio ) e o respectivo intervalo de confiança de 95%. A prevalência de agenesias dentais na amostra, excluindo os terceiros molares, foi de 88,6%. Dos 351 pacientes, 128 (36,4%) apresentavam agenesia no arco maxilar, 108 (30,8%) no mandibular e 115 (32,8%) nos dois arcos. Em relação ao hemiarco maxilar esquerdo, 52,4% apresentavam agenesia, no direito 55,0%, no mandibular esquerdo 48,7% e no direito 47,3%. Das anomalias associadas avaliadas, 28,5% microdontia, 28,2% hipoplasia de esmalte, 7,4% apresentavam irrupção ectópica de canino superior por palatino, 6,6% distoangulação, 3,9% transposição de canino/pré-molar superior, 4,3% infraoclusão, 3,7 supranumerário, 3,7% mesioangulação, 0,6% transposição de incisivo/canino inferior, e, quando comparadas com a população em geral, observou que 96,1 vezes mais chance de apresentar mesioangulação do segundo molar inferior; 34,6 vezes mais chance de apresentar distoangulação; 15,9 vezes mais chance de apresentar transposição canino/pré-molar superior; 14,3 vezes mais chance de apresentar transposição de incisivo/canino inferior; 9 vezes mais chance de hipoplasia; a microdontia do incisivo lateral apresentou 8,1 vezes mais chance; 5,2 vezes mais chance de apresentar irrupção ectópica do canino superior por palatino, e, em relação à infraoclusão, apresentando uma menor chance do que a população geral. A partir dos resultados obtidos, verificou-se uma forte associação entre a agenesia de dentes permanentes, correlacionando com outras anomalias dentais importantes. Foi constatado de que pacientes com agenesia de dentes permanentes apresentam uma prevalência aumentada de hipoplasia de esmalte e de que agenesias e outras anomalias associadas apresentam-se interligadas geneticamente entre si.