Das Plattenepithelkarzinom stellt mit über 90% die häufigste maligne Neubildung innerhalb der Mundhöhle mit gravierenden funktionellen Einschränkungen für die betroffenen Patienten und hoher Mortalität dar. In den meisten Fällen bestehen bereits vor der malignen Transformation visuell erkennbare Veränderungen mit höherem Entartungspotential, sogenannte potenziell maligne Veränderungen. Die vorliegende Arbeit beschäftigt sich mit einem experimentellen Verfahren zur oralen Tumorfrüherkennung und Dignitätsabklärung von potenziell malignen Veränderungen der Mundschleimhaut. Grundlage bildet das Verfahren des „intact cell peptidome profiling“ (ICPP) mittels MALDI-TOF MS anhand von Präparaten oraler Bürstenbiopsien. Untersucht wurden 16 Proben oraler Plattenepithelkarzinome, 69 Fälle von oralem Lichen planus, 26 orale Leukoplakien, 21 andere orale Veränderungen sowie 56 Mundschleimhautläsionen an Fanconi-Anämie erkrankter Patienten. Die Methode eignet sich zur Unterscheidung zwischen gesunder Mundschleimhaut und maligne verändertem Gewebe, wie mit einer Sensitivität von 86 % und einer Spezifität von 100 % belegt wurde. Eine Differenzierung zwischen den einzelnen Mundschleimhautveränderungen und gesundem Gewebe konnte nicht erreicht werden. Die Untersuchungsreihe ist als vielversprechend einzuschätzen, um ein weiterführendes diagnostisches Verfahren zu entwickeln, dass den Untersucher durch eine objektive Messmethode unterstützen und Sensitivität und Spezifität der Bürstenbiopsie steigern könnte.

La morbi-mortalité élevée des carcinomes épidermoïdes de la cavité orale (CECO), qui peuvent se développer à partir de lésions orales à potentiel malin (LOPM), rend indispensable le développement de nouvelles stratégies thérapeutiques. Le décryptage de l’hétérogénéité moléculaire aux différentes étapes de la carcinogénèse orale pourrait permettre de personnaliser les stratégies thérapeutiques de prévention et de traitement de ces cancers. Notre objectif était de caractériser l’hétérogénéité transcriptomique des LOPM et des CECO.Nous avons d’abord défini des signatures transcriptomiques associées aux changements histologiques de la carcinogénèse orale observés dans le modèle murin induit par le 4-NQO, montrant la pertinence de l’analyse de la dynamique temporelle du transcriptome pour améliorer la prévention des CECO. Cependant, ce modèle ne représentant qu’un sous-groupe particulier des CECO, nous avons ensuite étudié l’hétérogénéité inter-lésionnelle des LOPM en identifiant deux sous-types transcriptomiques principaux nommés « classical » et « immunological », qui sont caractérisés par différents biomarqueurs de risque de CECO.Au stade invasif, nous avons également étudié l’hétérogénéité transcriptomique des CECO HPV-négatifs entre les patients non-fumeurs non-buveurs (NFNB) et les patients fumeurs buveurs (FB). Le microenvironnement immunitaire était la principale différence biologique entre NFNB et FB, suggérant un bénéfice accru des immunothérapies chez les NFNB. Le profil transcriptomique de réponse antivirale observé dans les CECO des NFNB pourrait être en faveur de leur origine virale. En conclusion, l’hétérogénéité transcriptomique des LOPM et CECO suggère de personnaliser les stratégies thérapeutiques des patients porteurs de ces lésions / Oral squamous cell carcinomas (OSCC), which may develop from oral premalignant lesions (OPL), are associated with a substantial morbidity and mortality. A better understanding of the molecular heterogeneity at different steps of oral carcinogenesis may help to refine prevention and treatment strategies of patients suffering from OPL and OSCC. Our goal was to decipher transcriptomic hetereogeneity of OPL as well as OSCC. Using the 4-NQO murine model of oral carcinogenesis, we first identified transcriptomic signatures that characterized the dynamics of gene expression changes through different stages of disease progression, and that could be relevant for refining prevention strategies. Because this model represents only a subgroup of patients suffering from OSCC, we then investigated inter-OPL molecular heterogeneity. We identified two distinct gene expression subtypes, which were named classical and immunological and were characterized by different biomarkers of cancer risk. At invasive steps, we investigated transcriptomic heterogeneity between HPV-negative OSCC from never-smoker never-drinker (NSND) and smoker drinker (SD) patients. The immune microenvironment was the main biological difference between OSCC from NSND and SD, suggesting higher clinical benefit of immunotherapies in OSCC from NSND. The antiviral gene expression profile of OSCC from NSND could suggest a viral origin.In conclusion, we investigated transcriptomic heterogeneity of OPL as well as OSCC, that could help to refine their prevention and treatment strategies

Leucoplasia oral (LO) é uma lesão potencialmente maligna, definida como uma placa branca que não pode ser caracterizada como outra doença da mucosa oral. Dentro de certo consenso, as LOs devem ser tratadas, mas nenhum tratamento disponível tem a capacidade de prevenir a transformação maligna. Este trabalho teve como objetivo avaliar a eficácia do tratamento cirúrgico das LOs por lasers de CO2 e diodo e verificar a ocorrência de desfechos clínicos de recidivas, desenvolvimento de novas lesões ou transformação maligna após o tratamento. Adicionalmente foi realizado estudo imunohistoquímico em material biopsiado das lesões e em tecido normal gengival (grupo controle). Fatores reconhecidamente de risco como hábitos nocivos (álcool e tabagismo), características clínicas das lesões, grau de displasia, bem como a expressão dos anticorpos investigados, foram analisados e relacionados com a ocorrência de desfechos clínicos em 40 pacientes atendidos no ambulatório de Estomatologia Clínica. Os cortes histológicos das lesões foram classificados de acordo com o grau de displasia e com um sistema binário, e subsequentemente foram testados para os anticorpos anti-p53, anti-COX-2 e anti- EGFR através de reação imuno-histoquímica. Análise de Kaplan-Meier, seguida do teste de log-rank e análise de regressão de Cox avaliaram a ocorrência de recorrência, desenvolvimento de novas lesões e transformação maligna e possíveis fatores relacionados com esses desfechos clínicos. Teste de odds ratio e de x2 avaliaram a expressão dos anticorpos investigados em LOs e grupo controle. Pacientes com LO apresentaram idade média de 60,5 anos e a relação homem/mulher foi de 1,35:1. Hábitos de tabagismo e etilismo foram prevalentes em homens. A maior parte das lesões era < 2 cm (57,1%), tinha aspecto homogêneo (67,3%) e displasia epitelial (61,2%); apenas 7 lesões eram de alto risco (sistema binário). Desfechos clínicos de recorrência, desenvolvimento de novas lesões ou transformação maligna foram observados em 37,5% dos pacientes; 2 pacientes desenvolveram malignidade em sítios distintos da LO inicial. Análise estatística mostrou associação entre desfecho de recorrência e lesões de alto risco, e entre desfecho de desenvolvimento de novas lesões e mulheres acima de 60 anos. Os anticorpos p53 e COX-2 foram mais expressos em LOs que no grupo controle, mas a expressão de nenhum anticorpo foi relacionada com os desfechos clínicos avaliados. O tratamento por lasers de alta potência (CO2 e diodo) mostrou-se eficiente na remoção das lesões, embora não tenha evitado desfechos clínicos de recorrência, desenvolvimento de novas lesões e transformação maligna. Lesões de alto risco e mulheres acima de 60 anos constituíram fatores de risco aos desfechos clínicos, enquanto os anticorpos analisados não foram eficientes para prognosticar a evolução das LOs. / Oral leukoplakia (OL) is a potentially malignant lesion, defined as a white patch that cannot be characterized as any other disease of the oral mucosa. In general, OL should be treated; however no treatment available has been able to prevent malignant transformation. The aim of this study was to evaluate the efficacy of surgical treatment with CO2 and diode lasers in 40 patients with OL and the occurrence of clinical outcomes of recurrence, development of new lesions or malignant transformation, after treatment. Additionally, an immunohistochemistry study was performed in OL biopsy-specimen and in gingival normal tissue (control group). Recognized risk factors such as habits (alcohol and tobacco), clinical characteristics of lesions, grade of dysplasia, as well as the expression of immunohistochemistry reaction were analyzed. Histological slides of lesions were classified according to the grade of dysplasia and a binary system, and subsequently tested for the anti-p53, anti-COX-2 and anti-EGFR antibodies by immunohistochemistry assay. Kaplan-Meier analysis along with log-rank test and Cox regression analysis were used to assess the occurrence of clinical outcomes and the association with risk factors. Odds ratio and x2 tests evaluated the expression of the investigated antibodies in OLs and in the control group. Patients with OL had a mean age of 60.5 years and the men/women ratio was of 1.35:1. Smoking and alcohol habits were more prevalent among men than in women. Lesions were clinically characterized as measuring less than 2 cm (57.1%), with a homogenous aspect (67.3%) and histologically with epithelial dysplasia (61.2%); only 7 lesions were classified as of high-risk (binary system). Clinical outcomes (recurrence, development of new lesions and malignant transformation) were observed in 37.5% patients; 2 patients developed malignancy in areas distant from the initial OL site. Statistical analysis showed association between recurrence and high-risk lesions, and between development of new lesions and women over 60 years old. Anti-P53 and anti-COX-2 antibodies were more expressed among OL than in the control group, but no antibody expression was related to the clinical outcomes analyzed. Surgical treatment with high-power lasers (CO2 and diode) showed to be efficient in the removal of OL lesions, but it did not avoid clinical outcomes of recurrence, development of new lesions and malignant transformation. High-risk lesions and women over 60 years old constituted risk factors for the clinical outcomes, while the analized antibodies were not usefull markers to characterize OL lesions with higher risk of malignancy.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A proteína óxido nítrico sintase induzível (iNOS) é a mais importante proteína da família das óxido nítrico sintases, a qual é capaz de produzir grandes quantidades de óxido nítrico. A indução permanente de iNOS foi levantada como potencialmente mutagênica, apresentando um papel central na biologia tumoral. O objetivo deste estudo é investigar o papel da iNOS no desenvolvimento de carcinomas de células escamosas bucais (CCEB), usando um modelo experimental de carcinogênese lingual em camundongos knockouts para NOS2 e amostras humanas derivadas da mucosa normal, leucoplasia bucal e CCEB. Camundongos selvagens (iNOS+/+) e knockout (iNOS-/-) para iNOS foram desafiados com 4-nitroquinolina-1-óxido (4NQO) diluída em água potável por 16 semanas e sacrificados após 0, 8 e 16 semanas de acompanhamento. As línguas foram removidas e o número de displasias e carcinomas foram contados. Sangue periférico destes camundongos foram analisados, por citometria de fluxo, em busca de células tumorais circulantes. Amostras humanas derivadas da mucosa normal, leucoplasia e CCEB, foram utilizadas para quantificar o RNA mensageiro (mRNA) de NOS2. As amostras humanas também foram imuno-coradas com anticorpos anti-iNOS e anti-nitrotirosina. Em ambos os grupos, foram observadas uma redução no número de displasias e um aumento de carcinomas da 16 semana até a 32 semanas. Camundongos iNOS-/- demonstraram menor número de lesões displásicas e neoplásicas em todos os períodos de avaliação, sendo menores e menos invasivas, quando comparados aos animais selvagens. Aparentemente, há uma tendência em ascensão nos níveis do mRNA e da proteína iNOS durante a carcinogênese bucal humana. Dados similares foram obtidos com a imuno-detecção de nitrotirosina. Além disso, as imuno-marcações de iNOS e nitrotirosina foram associadas a várias características clínicopatológicas dos CCEB (tamanho, presença de metástase, estadiamento e recidiva). Nossos resultados demonstraram que iNOS afeta o processo de carcinogênese bucal experimental e humana, estando associada com a gênese e progressão dos CCEB. Mais estudos devem ser feitos, para nos fornecer, uma compreensão profunda das funções de iNOS no desenvolvimento de câncer bucal. / Inducible nitric oxide synthase (iNOS) is most important protein of nitric oxide synthases family, which is capable to produce huge amounts of nitric oxide. Permanent induction of iNOS has been raised as potentially mutagenic; presenting pivotal roles in tumor biology. The aim of this study is to investigate the role of iNOS in the development of oral squamous cells carcinomas (OSCC), using a mouse model of oral carcinogenesis in NOS2 knockout animals and human samples derived from normal mucosa, leukoplakia and OSCC. Wild-type (iNOS+/+) and NOS2-knockout (iNOS-/-) mices, were challenged with 4- nitroquinoline- 1-oxide (4NQO) in drinking water for 16 weeks and killed after 0, 8 and 16 weeks of after treatment. Tongues were removed and the number of dysplasias and carcinomas was counted. Mice’s peripheral blood were analyzed by flux cytometry in search of circulating tumor cells. Human samples derived from normal mucosa, leukoplakia and OSCC, were utilized to relative quantify the amount of NOS2-mRNA. The human samples were also immune-stained with anti-iNOS and anti- Nitrotyrosine antibodies. In both groups, a reduction of dysplasias and an increase of carcinomas from week 16 to week 32 were observed. iNOS-/- mices had shown a small number of dysplastic and neoplastic lesion in all evaluated periods, moreover these lesions were usually smaller and less invasive when compared to wild type animals. Apparently, there is a rising tendency in the iNOS mRNA and protein levels during human oral carcinogenesis. Similar findings were obtained in the nitrotyrosine staining. Furthermore, iNOS and nitrotyrosine imuno-stained is associated with several clinic-pathological features of OSCC (site, presence of metastasis, staging and recidive). Our results shows that, iNOS affects the process of experimental and human oral carcinogenesis, being associated with OSCC genesis and progression. More studies should be done to provide us a deep understanding of the iNOS functions in oral cancer development. / Tese (Doutorado)

Leucoplasia oral (LO) é uma lesão potencialmente maligna, definida como uma placa branca que não pode ser caracterizada como outra doença da mucosa oral. Dentro de certo consenso, as LOs devem ser tratadas, mas nenhum tratamento disponível tem a capacidade de prevenir a transformação maligna. Este trabalho teve como objetivo avaliar a eficácia do tratamento cirúrgico das LOs por lasers de CO2 e diodo e verificar a ocorrência de desfechos clínicos de recidivas, desenvolvimento de novas lesões ou transformação maligna após o tratamento. Adicionalmente foi realizado estudo imunohistoquímico em material biopsiado das lesões e em tecido normal gengival (grupo controle). Fatores reconhecidamente de risco como hábitos nocivos (álcool e tabagismo), características clínicas das lesões, grau de displasia, bem como a expressão dos anticorpos investigados, foram analisados e relacionados com a ocorrência de desfechos clínicos em 40 pacientes atendidos no ambulatório de Estomatologia Clínica. Os cortes histológicos das lesões foram classificados de acordo com o grau de displasia e com um sistema binário, e subsequentemente foram testados para os anticorpos anti-p53, anti-COX-2 e anti- EGFR através de reação imuno-histoquímica. Análise de Kaplan-Meier, seguida do teste de log-rank e análise de regressão de Cox avaliaram a ocorrência de recorrência, desenvolvimento de novas lesões e transformação maligna e possíveis fatores relacionados com esses desfechos clínicos. Teste de odds ratio e de x2 avaliaram a expressão dos anticorpos investigados em LOs e grupo controle. Pacientes com LO apresentaram idade média de 60,5 anos e a relação homem/mulher foi de 1,35:1. Hábitos de tabagismo e etilismo foram prevalentes em homens. A maior parte das lesões era < 2 cm (57,1%), tinha aspecto homogêneo (67,3%) e displasia epitelial (61,2%); apenas 7 lesões eram de alto risco (sistema binário). Desfechos clínicos de recorrência, desenvolvimento de novas lesões ou transformação maligna foram observados em 37,5% dos pacientes; 2 pacientes desenvolveram malignidade em sítios distintos da LO inicial. Análise estatística mostrou associação entre desfecho de recorrência e lesões de alto risco, e entre desfecho de desenvolvimento de novas lesões e mulheres acima de 60 anos. Os anticorpos p53 e COX-2 foram mais expressos em LOs que no grupo controle, mas a expressão de nenhum anticorpo foi relacionada com os desfechos clínicos avaliados. O tratamento por lasers de alta potência (CO2 e diodo) mostrou-se eficiente na remoção das lesões, embora não tenha evitado desfechos clínicos de recorrência, desenvolvimento de novas lesões e transformação maligna. Lesões de alto risco e mulheres acima de 60 anos constituíram fatores de risco aos desfechos clínicos, enquanto os anticorpos analisados não foram eficientes para prognosticar a evolução das LOs. / Oral leukoplakia (OL) is a potentially malignant lesion, defined as a white patch that cannot be characterized as any other disease of the oral mucosa. In general, OL should be treated; however no treatment available has been able to prevent malignant transformation. The aim of this study was to evaluate the efficacy of surgical treatment with CO2 and diode lasers in 40 patients with OL and the occurrence of clinical outcomes of recurrence, development of new lesions or malignant transformation, after treatment. Additionally, an immunohistochemistry study was performed in OL biopsy-specimen and in gingival normal tissue (control group). Recognized risk factors such as habits (alcohol and tobacco), clinical characteristics of lesions, grade of dysplasia, as well as the expression of immunohistochemistry reaction were analyzed. Histological slides of lesions were classified according to the grade of dysplasia and a binary system, and subsequently tested for the anti-p53, anti-COX-2 and anti-EGFR antibodies by immunohistochemistry assay. Kaplan-Meier analysis along with log-rank test and Cox regression analysis were used to assess the occurrence of clinical outcomes and the association with risk factors. Odds ratio and x2 tests evaluated the expression of the investigated antibodies in OLs and in the control group. Patients with OL had a mean age of 60.5 years and the men/women ratio was of 1.35:1. Smoking and alcohol habits were more prevalent among men than in women. Lesions were clinically characterized as measuring less than 2 cm (57.1%), with a homogenous aspect (67.3%) and histologically with epithelial dysplasia (61.2%); only 7 lesions were classified as of high-risk (binary system). Clinical outcomes (recurrence, development of new lesions and malignant transformation) were observed in 37.5% patients; 2 patients developed malignancy in areas distant from the initial OL site. Statistical analysis showed association between recurrence and high-risk lesions, and between development of new lesions and women over 60 years old. Anti-P53 and anti-COX-2 antibodies were more expressed among OL than in the control group, but no antibody expression was related to the clinical outcomes analyzed. Surgical treatment with high-power lasers (CO2 and diode) showed to be efficient in the removal of OL lesions, but it did not avoid clinical outcomes of recurrence, development of new lesions and malignant transformation. High-risk lesions and women over 60 years old constituted risk factors for the clinical outcomes, while the analized antibodies were not usefull markers to characterize OL lesions with higher risk of malignancy.

Made available in DSpace on 2014-08-20T14:30:13Z (GMT). No. of bitstreams: 1 Dissertacaoo_Deise_de_ Avila_Silva.pdf: 596277 bytes, checksum: bb38f7b6e8b73ab071ecabe2d943800c (MD5) Previous issue date: 2012-09-14 / This study aims to evaluate the immunohistochemical expression of antibodie MAGE-(Y18) in potentially malignant oral lesions and malignant lesions in patients with or without factor risk, and also to check the interexaminers variability on histological classification of oral epithelial dysplasia. Paraffin-embedded samples of 20 cases of severe dysplasia/carcinoma in situ and 20 cases of intraoral squamous cell carcinoma (SCC) were used in the study, and in both groups the samples had been distributed between patients with and without other risk factors associated with the occurrence of injury (tobacco and alcohol). The positive immunohistochemical expression of MAGE(Y-18) was defined by a cytoplasmic staining pattern, and it was used a scoring system considering the homogeneity of the reaction. In order to verify the interexaminer variability when performing a histological classification of oral epithelial dysplasia, 75 cases of potentially malignant oral lesions were selected from a referral service in oral disease. Slides were read independently and blindly by three pathologists in two stages. In the first stage it was made available to examiners the slides stained with H & E along with the clinical information of each case, and pathologists had to classify the lesions: no dysplasia, mild dysplasia, moderate dysplasia, severe dysplasia or carcinoma in situ.In the second stage, it was not given access to clinical information to the examiners, and they had to classify slides into two categories: low risk (non-dysplastic lesions / mild dysplasia) and high risk (moderate or severe dysplasia / carcinoma in situ). . The results were positive in 4/20 PML and 17/20 SCC. Through the Kruskal-Wallis test, it was observed a statistically significant difference (p<0.05) between groups of CPB and the group of potentially malignant lesions (PML) without the risk factor. The Mann-Whitney test found a statistically significant difference between carcinomas and potentially malignant lesions (p<0.001). The Fisher Exact test showed no statistically significant difference between the lesions that had the same histological diagnosis when compared in subgroups of associated risk factor (p=1). Detection of MAGE antigen may be useful in identifying LPM that has a higher risk of progression to invasive SCC, but it seems to be unrelated to exposure to popular risk factors The agreement between the examiners and the gold standard ranged from low to moderate, regardless of the classification system that was used. In the first stage, the intraclass correlation coefficient showed a moderate agreement between examiners 1 and 3 (r = 0.479 and r = 0.544) and, a low agreement of the examiner 2 (r = 0.384). In the second phase, it was observed a moderate agreement between examiners 2 and 3 and the gold standard (k = 0.433 k = 0.422) and, a low concordance between the examiner 1 and the gold standard (k = 0.186).Taking into account that grading dysplasia is a subjective process and still there is no test that outperforms the histological observation on diagnosis of oral epithelial dysplasia, it is understood that the process of grading made by two or more examiners should be encouraged, in order to assist in defining more precisely the diagnostics / O objetivo deste trabalho foi avaliar a expressão imuno-histoquímica do MAGE (Y-18) em LPM e malignas de pacientes com e sem fator de risco associado, bem como verificar a variabilidade interexaminadores na classificação histológica das displasias epiteliais orais. Foram utilizadas amostras incluídas em parafina de 20 casos de displasia severa/carcinoma in situ e 20 casos de CEC intraoral, sendo que em cada grupo as amostras estavam distribuídas entre pacientes com e sem fator de risco associado à ocorrência da lesão (tabaco e álcool). A expressão imuno-histoquímica positiva de MAGE (Y-18) foi definida por um padrão de coloração citoplasmático, sendo utilizado um sistema de pontuação considerando a homogeneidade da reação. Para classificar as displasias epiteliais orais, 75 casos de lesões orais potencialmente malignas foram selecionados de um serviço de referência em patologia bucal. Três patologistas analisaram as lâminas de forma independente e cega em dois momentos.Na primeira etapa foram disponibilizadas aos examinadores as lâminas coradas em H&E juntamente com as informações clínicas de cada caso e os patologistas classificaram as lesões em sem displasia, displasia leve, moderada, severa ou carcinoma in situ. Na segunda etapa, os avaliadores não tiveram acesso às informações clínicas e classificaram as lâminas em duas categorias: baixo risco (lesão não displásica/displasia leve) e alto risco (displasia moderada/severa/carcinoma in situ). A análise das reações imuno-histoquímicas demonstrou positividade em 4/20 LPM e 17/20 CEC. Pelo teste de Kruskall-Wallis observou-se diferença estatisticamente significativa (p<0,05) entre os grupos de CEC e o grupo das lesões potencialmente malignas sem fator de risco. O teste de Mann-Whitney verificou diferença estatisticamente significativa entre os carcinomas e as lesões potencialmente malignas (p<0.001). O teste Exato de Fischer não demonstrou diferença estatisticamente significativa entre as lesões de mesmo diagnóstico histológico quando comparadas nos subgrupos de fator de risco associado (p=1). Nossos resultados sugerem que a detecção do antígeno MAGE pode ser útil na identificação de LPM com maior risco de progressão para o CEC invasivo, mas parece não ter relação com a exposição aos fatores de risco mais conhecidos. Quando na classificação das displasias, independente do sistema de classificação utilizado, a concordância entre os avaliadores e o padrão ouro variou de fraca a moderada.Na primeira etapa, o Coeficiente de Correlação Intraclasse demonstrou uma concordância moderada entre os avaliadores 1 e 3 (r=0,479 e r=0,544) e uma concordância baixa do avaliador 2 (r=0,384). No segundo momento observou-se uma concordância moderada entre os examinadores 2 e 3 e o padrão ouro (k=0,433 e k=0,422) e uma baixa concordância entre o avaliador 1 e o padrão ouro (k=0,186). Tendo em vista que a graduação da displasia é um processo subjetivo, e que ainda não dispomos de nenhum exame que supere a observação histológica no diagnóstico das displasias epiteliais orais, entendemos que o processo de graduação entre dois ou mais observadores deve ser incentivado, a fim de auxiliar na definição mais precisa do diagnóstico

Magister Chirurgiae Dentium - MChD / Purpose: To assess the oral health status of 4-15-year-old schoolchildren in the Western Region of the Eastern Cape Province, by determining the prevalence of dental caries, periodontal disease, dental fluorosis, malocclusion and oral mucosal lesions and to create baseline data for planning oral health services in this region. Materials and Methods: The prevalent analytic survey was undertaken on 822 schoolchildren between the ages of 4-15 years in 27 different schools. The sample size selected for this region by the Department of Statistics, University of Pretoria, for the National Oral Health Survey of 1999/2000 was used. The data on 209, 210, 209 and 194 scholars in the 4-5, 6, 12 and 15-year-old age groups respectively were collected. The World Health Organization's (1997) criteria were used to determine the prevalence of caries, periodontal treatment needs, the dental fluorosis, malocclusion and prevalence of oral mucosal lesions. Six calibrated and trained examiners recorded the data on a survey form. The WHO survey forms were used for data collection. The data were analysed and processed by the author on Microsoft Excel 2000. Results: The sample size consisted of 1.35 % Asian, 51.89 % Black, 26.07 % Coloured and 20.06 % White scholars. Nearly equal amounts of males (48.3 %) and females (51.7%) were examined. The dental caries prevalence in the primary dentition of 4-5-year-olds with an average age of 4.43 years was 40.67%, with a mean dmft of 3,56. The dental caries prevalence in the permanent dentition of6-, 12- and 15-year-oldage groups was 67.62%, 46.05% and 67.92% respectively. The mean DMFT for 6-, 12- and 15 year olds were 0.05, 1.19 and 2.02 respectively. Gender differences and differences in prevalence of dental caries between the populations groups were recorded. The Coloured children experienced the highest dental caries prevalence. In the 4-5- and 15-year-old groups the males were affected more than the females by dental caries. Prevalent differences were recorded between rural and urban areas in the same population group. The prevalence of periodontal disease in 373, 12-15-year-olds was 79.09%. Only 4.02 % were in need of dental hygiene instructions and polishing. Dental education, dental hygiene instructions, dental scaling and polishing were needed by 75.07% of the children. Dental fluorosis prevalence in 450, 6-15-year-olds was 13.03%. Dental fluorosis did not affect 86.97% of the scholars; 10.63% had mild fluorosis and 2.05% was severely affected. The mean fluoride concentration in the drinking water in this region were 1.07 mgIL, ranging between 0.3-3 mgIL. Definite malocclusion was recorded in only 0.48% of the 12-year-old group, whom needed elective treatment. In the 12-year-olds, 99.52% needed no or slight treatment for no or minor malocclusions. The majority of children had no oral mucosal lesions (91.55%). The prevalence of oral mucosal lesions was 8.5% in this survey. The most frequent conditions were traumatic lesions (1.96%), dento-alveolar abscess (1.22%) and herpes labialis (1.22%). The intra-examiner reliability for caries, dental fluorosis, periodontal treatment needs and prevalence of malocclusions was 97.66%, 100%, 88.89% and 86.67% respectively. The inter-examiner reliability was 98.75%, 98.34%, 100%, 100% and 100% respectively for the five examiners. Conclusion: This survey indicated a higher prevalence of dental caries in the primary dentition (63.48%), than the permanent dentition (41.3%). The mean dmft was 3.65 and the DMFT 1.2, which indicated a low mean caries experience for these children. The WHO goal for the year 2000 for the 6-year-olds of 50% being caries free has not reached for only 32.56% were caries free. The mean DMFT of 1.2 for 12-year-olds in this survey is below the WHO goal of a mean DMFT of 1.5 or less. The lack of available preventative service provision, were ) indicated by the low percentage of fissure sealants (2.8%). The need for dental treatment was highlighted by the need mostly for one-surface restorations. Preventative treatment, two-surface fillings and extractions were also needed. Periodontal disease was a major public oral health concern for this region for a prevalence of 79.09% was recorded for the 12-15-year-olds. The majority of the children affected by periodontal disease (75.07%) were in need of professional cleaning and calculus removal. The prevalence of dental fluorosis was 8.2%, 19.87% and 13.05% for 6-, 12- and IS-year age groups respectively. The prevalence of malocclusion was 0.48% for the 12-year-old group. The prevalence of oral mucosa lesions was 8.5% for 4-15-year-old schoolchildren. Therefore, the conclusion can be made that dental fluorosis; malocclusions and oral mucosal lesions were no public concern in this region. The major public oral health concerns were dental caries in the primary dentition and periodontal disease in all age groups. Recommendations: Dental services in this region should be directed towards prevention of dental caries in the primary dentition and periodontal disease in all age groups. The focus of dental services should be primarily on preventative programs and treatments. The public dental treatments needs indicated in this survey, namely scaling and polishing, restorations and extractions, consists of the primary health care package delivery. Currently, no evaluation tool exists to monitor the efficiency of oral health programs, no baseline data for the Province exists. Therefore, the urgent need for dental research and oral health service planning and delivery are recommended.