Magister Scientiae Dentium - MSc(Dent) / Background: Plaster study models are routinely used in an Orthodontic practice. With the recent introduction of digital models, an alternative is now available, whereby three dimensional images of models can be analyzed on a computer. Aims and objectives: The aim of this study was to compare the measurements taken on digital models created from scanning the impression, digital models created from scanning the plaster model, and measurements done on the plaster models. The objectives were: Measurement differences between those taken directly on plaster models compared with measurements on digital models created from scanned impressions and digital models created from scanned plaster models. Methods: The study sample was selected from the patient records of one Orthodontist. They consisted of 26 pre-treatment records of patients that were coming for orthodontic treatment. Alginate impressions were taken of the maxillary and the mandibular arches. Each impression was scanned using a 3Shape R700™ scanner. Ortho Analyzer software from 3Shape was used to take the measurements on the digital study models. Within 24 hours plaster study models were cast from the impressions, and were scanned using a 3Shape R700™ scanner. On the plaster models the measurements were done with a MAX-CAL electronic digital calliper. The mesiodistal width as well as intermolar and intercanine width for both the maxillary and mandibular models were recorded.Results and discussion: Box plots used to compare the variability in each of the three measurement methods, suggest that measurements are less variable for Plaster. Plaster measurements for tooth widths were significantly higher (mean 7.79) compared to a mean of 7.74 for Digital Plaster and 7.69 for Digital impression. A mixed model analysis showed no significant difference among methods for arch width. Conclusions: Digital models offer a highly accurate alternative to the plaster models with a high degree of accuracy. The differences between the measurements recorded from the plaster and digital models are likely to be clinically acceptable.

Magister Scientiae Dentium - MSc(Dent) / The aim of this present study was to compare the accuracy of digital and printed study models with plaster study models, that are considered the gold standard. The objectives were to compare the accuracy of measurements obtained from digital and printed study models with those of plaster study models, to establish which type of study model yielded the most accurate measurements in comparison to plaster study models and to identify possible disadvantages and errors that can be made using any of the three types of study models.

Introdução: Sabe-se que as cirurgias primárias de lábio e palato em indivíduos com fissura transforame incisivo unilateral (FTIU) provoca inibição do crescente deslocamento da base maxilar, bem como da região dentoalveolar. No entanto, a maxila dividida em dois segmentos diferentes, com as condições anatomicas variadas, assim como as alterações transversais e ântero-posterior, pode ser um dos fatores etiológicos para proporcionar deficiência maxilar e dentoalveolar. Proposição: Este estudo teve como objetivo avaliar, por modelos de gesso obtidos antes de cirurgias primárias de indivíduos com FTIU, a influência da relação espacial anteroposterior e transversal dos segmentos maxilares e da amplitude da fissura no crescimento maxilar e relação oclusal avaliado pelo índice de cinco anos de idade. Métodos: Um total de 357 modelos de gesso do arco maxilar, da fase prévia as cirurgias primárias de lábio e palato, foram digitalizados e avaliados quanto à amplitude da fissura e relação espacial anteroposterior e transversal dos segmentos maxilares. Os grupos para classificação foram: Grupo 1: segmentos maxilares em contato na região anterior; Grupo 2: segmentos maxilares com espaçamento entre os segmentos maxilares e diferentes graus de discrepância ântero-posterior (a = leve, b = moderada e c = grave), e Grupo 3: segmentos maxilares em colapso, com o segmento menor apresentando flexão para a região mediana. A amplitude da fissura foi classificada em estreita (E), regular (R), ampla (A) e muito ampla (AA), pelo método visual subjetivo na região anterior, média e posterior. Fotografias intra-orais aos seis anos de idade foram utilizadas para a classificação do relacionamento intra e inter arcos dentro de escores de 1 a 5, seguindo as características oclusais do índice dos cinco anos e depois relacionada com a relação espacial anteroposterior e transversal dos segmentos maxilares e com a amplitude da fissura. Resultados e discussão: Um único examinador realizou as avaliações e o teste kappa demonstrou que a concordância intra-examinador foi quase perfeita. Para a avaliação estatística entre o índice de oclusal, a relação espacial e a amplitude da fissura foi realizada o coeficiente de correlação de Spearman. Foi definida a relação espacial anteroposterior dos segmentos maxilares, demonstrando uma prevalência de 56,82% de Grupo 2b e, menos prevalente obteve-se o Grupo 3. Na análise dos índices oclusais deste trabalho observou-se a maior prevalência do índice 3, com 36,33%, cujo prognóstico para o tratamento ortodôntico é regular. Não houve significância estatística na correlação entre o índice oclusal e discrepância anteroposterior entre os segmentos maxilares. No entanto, isso não foi observado para a amplitude da fissura que estatisticamente influenciou os resultados das relações interarcos, com tendências de índices oclusais maiores em maiores amplitudes de fissura, demonstrando prognosticos de crescimento maxilar mais pobre. Conclusões: Os diferentes graus de discrepância ânteroposterior entre os segmentos maior e menor não influenciou a relação interarcos. A amplitude da fissura entre os segmentos prévio às cirurgias primárias influenciou estatisticamente na relação interarcos, com crescimento maxilar mais pobre em indivíduos que apresentaram maiores amplitudes de fissura. / Background and Purpose: It is known that primary lip and palate repair in complete unilateral cleft lip and palate (CUCLP) causes inhibition of increasing displacement of the maxillary base, as well as of the dentoalveolar region. However, the maxilla divided in two different segments with varied anatomical conditions, as well as the transverse and anteroposterior changes, may be among the etiologic factors to yield deficient maxillary and dentoalveolar growth. This study aimed to evaluate, by dental casts obtained before primary surgeries of patients with CUCLP, the influence of the anteroposterior and transverse spatial relationship of maxillary segments and the cleft width on the maxillary growth and occlusal relationship scored by the Five years old Index. Methods: A total of 357 dental casts of the maxillary arch before lip and palate closure were scanned and evaluated as to the cleft width and anteroposterior and transverse spatial relationship of maxillary segments. Group 1 had maxillary segments contacting in the anterior region; Group 2 presented maxillary segments with spacing between them and different degrees of anteroposterior discrepancy (a=mild; b=moderate and c=severe), and Group 3 exhibited collapse between the two segments, being that the lesser segment presented flexure to the median region. The cleft width was scored as narrow (N), regular (R), wide (W) and very wide (WW) by the visual method in anterior, medium and posterior regions. The intraoral photographs at six years of age were used for the rating dental relationship from 1 to 5 scores, following characteristics of Five years old Index.and then relating to the spatial relationship of the anteroposterior and lateral segments jaws. Results: A single investigator performed the assessments and the kappa test showed that the intraexaminer agreement was almost perfect. The statistical evaluation between the occlusal index and the spatial relationship and cleft width was performed using the Spearman correlation coefficient. It was defined spatial relation, showing a prevalence of 56.82% 2b Group and the less prevalent obtained in Group 3. In the occlusal analysis of this work observed a higher prevalence of index 3, with 36.33%, whose prognosis for orthodontic treatment is regular. There was no statistically significant in the correlation between the occlusal and anteroposterior discrepancy between the maxillary segments. However, this was not observed for the cleft width before primary surgery, which statistically influenced the outcomes of the occlusal index. Conclusions: The different degrees of anteroposterior discrepancy of greater and lesser segments did not influence the interarch relationship. The cleft width between the maxillary segments influenced the interarch relationship, with poor maxillary growth in greater cleft widths.

Thesis--University of Oklahoma. / Includes bibliographical references (leaves 52-53).

This study investigated arch dimension changes associated with growth and tooth wear in Australian Aboriginals aged from age 8 to 15 years using 2D and 3D digital imaging systems. Serial dental casts of Australian Aboriginals from Yuendumu were used in the study. The sample comprised 25 females and 24 males for whom casts were available at ages of 8, 12 and 15 years ( a total of 294 dental study casts). The primary method of data acquisition involved obtaining digital photographs and digitizing the images using an Apple IIGS computer and customised software program. A subset of 40 dental stone models (5 individuals at ages 8, 12, 15 and 18 years) were duplicated and scanned using the Minolta Vivid 900 laser surface scanner at the DSIRO Laboratories, National University Singapore. The 3-D images were digitised using the Rapidform software package (Inus, technology, Seoul, Korea). Study variables included mesiodistal crown diameters, arch widths, arch depths and arch lengths. Mesiodistal crown dimensions in males tended to be larger than those in females. All arch dimensions were significantly larger in males than females. Upper and lower Intercanine width increased from age 8 to age 12 years but did not change thereafter. Upper and lower intermolar widths increased with age from 8 years to 15 years while arch depth decreased. No significant reduction in arch lengths was found from age 12 to 15 years. The two imaging systems were comparable in their measurement reliability, although the 2D method provided consistently larger crown diameters than the 3D method. Changes in arch dimensions with age in the Aboriginal sample were similar to those reported for other populations. However, no measurable change was detected in arch length over time, even though the Aboriginals had abrasive diets that would be expected to contribute to interproximal wear. It was concluded that the 2D and 3D imaging methods were suitable for clinical use but would require further refinement for research projects aimed at assessing minor changes in arch lengths associated with interproximal wear. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1347947 / Thesis (D.Clin.Dent.) -- University of Adelaide, School of Dentistry, 2008

Introdução: Sabe-se que as cirurgias primárias de lábio e palato em indivíduos com fissura transforame incisivo unilateral (FTIU) provoca inibição do crescente deslocamento da base maxilar, bem como da região dentoalveolar. No entanto, a maxila dividida em dois segmentos diferentes, com as condições anatomicas variadas, assim como as alterações transversais e ântero-posterior, pode ser um dos fatores etiológicos para proporcionar deficiência maxilar e dentoalveolar. Proposição: Este estudo teve como objetivo avaliar, por modelos de gesso obtidos antes de cirurgias primárias de indivíduos com FTIU, a influência da relação espacial anteroposterior e transversal dos segmentos maxilares e da amplitude da fissura no crescimento maxilar e relação oclusal avaliado pelo índice de cinco anos de idade. Métodos: Um total de 357 modelos de gesso do arco maxilar, da fase prévia as cirurgias primárias de lábio e palato, foram digitalizados e avaliados quanto à amplitude da fissura e relação espacial anteroposterior e transversal dos segmentos maxilares. Os grupos para classificação foram: Grupo 1: segmentos maxilares em contato na região anterior; Grupo 2: segmentos maxilares com espaçamento entre os segmentos maxilares e diferentes graus de discrepância ântero-posterior (a = leve, b = moderada e c = grave), e Grupo 3: segmentos maxilares em colapso, com o segmento menor apresentando flexão para a região mediana. A amplitude da fissura foi classificada em estreita (E), regular (R), ampla (A) e muito ampla (AA), pelo método visual subjetivo na região anterior, média e posterior. Fotografias intra-orais aos seis anos de idade foram utilizadas para a classificação do relacionamento intra e inter arcos dentro de escores de 1 a 5, seguindo as características oclusais do índice dos cinco anos e depois relacionada com a relação espacial anteroposterior e transversal dos segmentos maxilares e com a amplitude da fissura. Resultados e discussão: Um único examinador realizou as avaliações e o teste kappa demonstrou que a concordância intra-examinador foi quase perfeita. Para a avaliação estatística entre o índice de oclusal, a relação espacial e a amplitude da fissura foi realizada o coeficiente de correlação de Spearman. Foi definida a relação espacial anteroposterior dos segmentos maxilares, demonstrando uma prevalência de 56,82% de Grupo 2b e, menos prevalente obteve-se o Grupo 3. Na análise dos índices oclusais deste trabalho observou-se a maior prevalência do índice 3, com 36,33%, cujo prognóstico para o tratamento ortodôntico é regular. Não houve significância estatística na correlação entre o índice oclusal e discrepância anteroposterior entre os segmentos maxilares. No entanto, isso não foi observado para a amplitude da fissura que estatisticamente influenciou os resultados das relações interarcos, com tendências de índices oclusais maiores em maiores amplitudes de fissura, demonstrando prognosticos de crescimento maxilar mais pobre. Conclusões: Os diferentes graus de discrepância ânteroposterior entre os segmentos maior e menor não influenciou a relação interarcos. A amplitude da fissura entre os segmentos prévio às cirurgias primárias influenciou estatisticamente na relação interarcos, com crescimento maxilar mais pobre em indivíduos que apresentaram maiores amplitudes de fissura. / Background and Purpose: It is known that primary lip and palate repair in complete unilateral cleft lip and palate (CUCLP) causes inhibition of increasing displacement of the maxillary base, as well as of the dentoalveolar region. However, the maxilla divided in two different segments with varied anatomical conditions, as well as the transverse and anteroposterior changes, may be among the etiologic factors to yield deficient maxillary and dentoalveolar growth. This study aimed to evaluate, by dental casts obtained before primary surgeries of patients with CUCLP, the influence of the anteroposterior and transverse spatial relationship of maxillary segments and the cleft width on the maxillary growth and occlusal relationship scored by the Five years old Index. Methods: A total of 357 dental casts of the maxillary arch before lip and palate closure were scanned and evaluated as to the cleft width and anteroposterior and transverse spatial relationship of maxillary segments. Group 1 had maxillary segments contacting in the anterior region; Group 2 presented maxillary segments with spacing between them and different degrees of anteroposterior discrepancy (a=mild; b=moderate and c=severe), and Group 3 exhibited collapse between the two segments, being that the lesser segment presented flexure to the median region. The cleft width was scored as narrow (N), regular (R), wide (W) and very wide (WW) by the visual method in anterior, medium and posterior regions. The intraoral photographs at six years of age were used for the rating dental relationship from 1 to 5 scores, following characteristics of Five years old Index.and then relating to the spatial relationship of the anteroposterior and lateral segments jaws. Results: A single investigator performed the assessments and the kappa test showed that the intraexaminer agreement was almost perfect. The statistical evaluation between the occlusal index and the spatial relationship and cleft width was performed using the Spearman correlation coefficient. It was defined spatial relation, showing a prevalence of 56.82% 2b Group and the less prevalent obtained in Group 3. In the occlusal analysis of this work observed a higher prevalence of index 3, with 36.33%, whose prognosis for orthodontic treatment is regular. There was no statistically significant in the correlation between the occlusal and anteroposterior discrepancy between the maxillary segments. However, this was not observed for the cleft width before primary surgery, which statistically influenced the outcomes of the occlusal index. Conclusions: The different degrees of anteroposterior discrepancy of greater and lesser segments did not influence the interarch relationship. The cleft width between the maxillary segments influenced the interarch relationship, with poor maxillary growth in greater cleft widths.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Made available in DSpace on 2016-08-03T16:31:09Z (GMT). No. of bitstreams: 1 Abstract - final.pdf: 11947 bytes, checksum: 435d59eefe9021e83e2a9ae702c1de13 (MD5) Previous issue date: 2005-03-01 / The objective of this study was to evaluate the dental arch asymmetry s degree in individuals with normal occlusion and Class II malocclusion and to investigate the sexual dimorphism presence s in these individuals. 180 pars of study models were measured with a new appliance designed for analysis of dental arch asymmetries. These models were divided in three groups: Group 1: individuals with normal occlusion; Group 2: individuals with malocclusion Class II division 1; and Group 3: individuals with malocclusion Class II division 2. These individuals had age between 12 to 21 years old. Verified that everybody had dental arch asymmetry; the Group 1 had the smallest dental arch asymmetry s degree; the groups 2 and 3 had similar dental arch asymmetry s degree; the mandibular dental arches had a bigger dental arch asymmetry s degree than the maxillary dental arches; the midline had a opposite direction of the side of molars that had a mesial position, except for the maxillary dental arch in the Group 2 (Class II division 1); and, clinically, there wasn t sexual dimorphism for the dental arch asymmetry s evaluation. / A assimetria das arcadas dentárias constitui um assunto de grande importância estudado por profissionais de Ortodontia na elaboração de um diagnóstico correto, planejamento e execução de um tratamento ortodôntico bem sucedido. O objetivo deste estudo foi avaliar o grau de assimetria das arcadas dentárias em indivíduos com oclusão normal e má oclusão de Classe II, divisão 1 e 2, bem como o dimorfismo sexual existente. Foram avaliados 180 pares de modelos de estudo de indivíduos do sexo masculino e feminino, na faixa etária de 12 a 21 anos, divididos em 3 grupos de 60 pares de modelos, de acordo com a má oclusão. Os grupos foram classificados em: Grupo 1 - indivíduos com oclusão normal, Grupo 2 - indivíduos com má oclusão de Classe II divisão 1 (Cl II 1), e Grupo 3 - indivíduos com má oclusão de Classe II divisão 2 (Cl II 2). Os modelos foram medidos utilizando-se um aparelho inédito, idealizado e fabricado exclusivamente para a análise de assimetria das arcadas dentárias. Para a análise de assimetria foram realizadas 2 medições angulares desvio de linha média (DLM), posicionamento dos caninos (PC) e 3 lineares distância dos caninos à rafe palatina (DC), distância inter-caninos (DIC), posicionamento dos primeiros molares no sentido ântero-posterior (PM). Concluiu-se que a ocorrência de assimetria nas arcadas dentárias independe da má oclusão. O Grupo 1 apresentou um menor grau de assimetria nas arcadas dentárias em relação aos grupos 2 e 3, os quais apresentaram um grau de assimetria semelhante. O grau de assimetria nas arcadas dentárias inferiores, nos 3 grupos, foi maior do que nas arcadas dentárias superiores. A direção do desvio da linha média apresentou uma correlação inversamente proporcional do lado em que o molar se apresentava mesializado, nas arcadas superior e inferior dos três grupos, com exceção da arcada superior no Grupo 2 (Classe II divisão 1). Houve dimorfismo sexual estatisticamente significante para algumas medidas, porém é importante considerar os baixos valores e a disposição, destas diferenças, entre as medidas realizadas, a qual revela ter se tratado de dados obtidos ao acaso.