Reliability of Bolton analysis evaluation in tridimensional virtual models

Objective: The present study aimed at evaluating the reliability of Bolton analysis in tridimensional virtual models, comparing it with the manual method carried out with dental casts.Methods:The present investigation was performed using 56 pairs of dental casts produced from the dental arches of patients in perfect conditions and randomly selected from Universidade Federal da Bahia, School of Dentistry, Orthodontics Postgraduate Program. Manual measurements were obtained with the aid of a digital Cen-Tech 4"(r) caliper (Harpor Freight Tools, Calabasas, CA, USA). Subsequently, samples were digitized on 3Shape(r)R-700T scanner (Copenhagen, Denmark) and digital measures were obtained by Ortho Analyzer software.Results:Data were subject to statistical analysis and results revealed that there were no statistically significant differences between measurements with p-values equal to p = 0.173 and p= 0.239 for total and anterior proportions, respectively.Conclusion:Based on these findings, it is possible to deduce that Bolton analysis performed on tridimensional virtual models is as reliable as measurements obtained from dental casts with satisfactory agreement.

Objetivo: o presente estudo teve como objetivo avaliar a confiabilidade da análise de Bolton em modelos virtuais tridimensionais, comparando-a com a realizada em modelos de gesso.Métodos:foram utilizados 56 pares de modelos de gesso das arcadas dentárias de pacientes oriundos do Curso de Especialização em Ortodontia da Faculdade de Odontologia da Universidade Federal da Bahia, escolhidos aleatoriamente e em perfeito estado. Medidas manuais foram obtidas utilizando-se o paquímetro digital Cen-Tech(r) 4" (Harpor Freight Tools, Calabasas, CA, EUA). Em seguida, os mesmos foram digitalizados pelo scanner R-700TM(3Shape(r), Copenhagen, Dinamarca) e, por meio do programa Ortho AnalyzerTM, da mesma marca, foram obtidas as medidas digitais.Resultados:os dados foram submetidos a testes estatísticos e os resultados demonstraram que não houve diferença estatisticamente significativa nos dois tipos de medições com valores de p = 0,173 e p = 0,239, respectivamente, para as proporções total e anterior.Conclusão:com base nesses achados, pode-se inferir que a análise de Bolton realizada em modelos virtuais tridimensionais é tão confiável quanto a obtida em modelos de gesso, apresentando uma concordância satisfatória.

Periodontal and dental effects of surgically assisted rapid maxillary expansion, assessed by using digital study models

OBJECTIVE: The present study assessed the maxillary dental arch changes produced by surgically assisted rapid maxillary expansion (SARME). METHODS: Dental casts from 18 patients (mean age of 23.3 years) were obtained at treatment onset (T1), three months after SARME (T2) and 6 months after expansion (T3). The casts were scanned in a 3D scanner (D-250, 3Shape, Copenhagen, Denmark). Maxillary dental arch width, dental crown tipping and height were measured and assessed by ANOVA and Tukey's test. RESULTS: Increased transversal widths from T1 and T2 and the maintenance of these values from T2 and T3 were observed. Buccal teeth tipping also showed statistically significant differences, with an increase in all teeth from T1 to T2 and a decrease from T2 to T3. No statistically significant difference was found for dental crown height, except for left first and second molars, although clinically irrelevant. CONCLUSION: SARME proved to be an effective and stable procedure, with minimum periodontal hazards. .

OBJETIVOS: o presente estudo teve o objetivo de avaliar as alterações dentárias e periodontais decorrentes da Expansão Rápida da Maxila Assistida Cirurgicamente (ERMAC). MÉTODOS: foram obtidos os modelos de gesso de 18 pacientes (média de idade de 23,3 anos), ao início (T1), 3 meses após a ERMAC (T2) e 6 meses após a expansão (T3). Os modelos foram digitalizados (Scanner 3D 3Shape D-250) e mensuraram-se as distâncias transversais, bem como a inclinação e a altura da coroa clínica dos dentes posteriores. Para análise dos resultados, aplicou-se a análise de Variância e o teste de Tukey. RESULTADOS: nas distâncias transversais, observou-se um aumento de T1 para T2 e uma manutenção de T2 para T3. As inclinações dentárias demonstraram diferenças estatisticamente significativas em alguns dentes; porém, numericamente tenderam a um aumento de T1 para T2 e a uma diminuição de T2 para T3. Não se observou diferença estatisticamente significativa na altura da coroa clínica, exceto nos primeiros e segundos molares do lado esquerdo, porém, clinicamente irrelevante. CONCLUSÕES: a ERMAC demonstrou ser um procedimento efetivo e estável, com mínima repercussão periodontal. .

Comparative evaluation of the accuracy of pick up transfer impressions performed with two different types of trays

Introduction: The success of implant-supported prostheses is related to the passive union between the prostheses’ connections and the implants, so it is necessary to obtain an accurate working cast. Objective: To evaluate the accuracy of the transfer impressions of implants performed with individual acrylic resin trays and conventional trays using polyvinyl siloxane. Material and methods: To carry out the transfer impressions, a master cast with four external hexagon implants parallel to each other was used. Five impressions were made with individual acrylic resin trays and five other impressions with modified conventional trays, opened in the region of the implants. The linear measurements between the implants were made with a digital caliper with an accuracy of 0.01 mm and the results were statistically evaluated (alpha = %). Results: For the points AB and BC, the measurements obtained with the individual trays were statistically similar to the master cast. For the points CD and DA no statistical differences among the three groups were observed. Conclusion: Given the obtained results and the methodology used, it can be concluded that the impressions performed with individual trays presented higher accuracy compared to the ones obtained with conventional trays.

Comparison of space analysis performed on plaster vs. digital dental casts applying Tanaka and Johnston's equation

OBJECTIVE: The purpose of this study was to compare dental size measurements, their reproducibility and the application of Tanaka and Johnston regression equation in predicting the size of canines and premolars on plaster and digital dental casts. METHODS: Thirty plaster casts were scanned and digitized. Mesiodistal measurements of the teeth were then performed with a digital caliper on the plaster and digital casts using O3d software system (Widialabs©).The sum of the sizes of the lower incisors was used to obtain predictive values of the sizes of the premolars and canines using the regression equation, and these values were compared with the actual sizes of the teeth. The data were statistically analyzed by applying to the results Pearson's correlation test, Dahlberg's formula, paired t-test and analysis of variance (p<0.05). RESULTS: Excellent intraexaminer agreement was observed in the measurements performed on both dental casts. No random error was present in the measurements obtained with the caliper and systematic error (bias) was more frequent in the digital casts. Space prediction obtained by applying the regression equation was greater than the sum of the canines and premolars on the plaster and digital casts. CONCLUSIONS: Despite an adequate reproducibility of the measurements performed on both casts, most measurements on the digital casts were higher than those on the plaster casts. The predicted space was overestimated in both models and significantly higher in the digital casts.

OBJETIVO: comparar medidas de tamanhos dentários, suas reprodutibilidades e a aplicação da equação de regressão de Tanaka e Johnston na predição do tamanho dos caninos e pré-molares em modelos de gesso e digital. MÉTODOS: trinta modelos de gesso foram escaneados para obtenção dos modelos digitais. As medidas do comprimento mesiodistal dos dentes foram obtidas com paquímetro digital nos modelos de gesso e nos modelos digitais utilizando o software O3d (Widialabs). A somatória do tamanho dos incisivos inferiores foi utilizada para obter os valores de predição do tamanho dos pré-molares e caninos utilizando equação de regressão, e esses valores foram comparados ao tamanho real dos dentes. Os dados foram analisados estatisticamente, aplicando-se aos resultados o teste de correlação de Pearson, a fórmula de Dahlberg, o teste t pareado e a análise de variância (p < 0,05). RESULTADOS: excelente concordância intraexaminador foi observada nas medidas realizadas em ambos os modelos. O erro aleatório não esteve presente nas medidas obtidas com paquímetro, e o erro sistemático foi mais frequente no modelo digital. A previsão de espaço obtida pela aplicação da equação de regressão foi maior que a somatória dos pré-molares e caninos presentes nos modelos de gesso e nos modelos digitais. CONCLUSÃO: apesar da boa reprodutibilidade das medidas realizadas em ambos os modelos, a maioria das medidas dos modelos digitais foram superiores às do modelos de gesso. O espaço previsto foi superestimado em ambos os modelos e significativamente maior nos modelos digitais.

Maxillary constriction: are there differences between anterior and posterior regions? / Atresia maxilar: há diferenças entre as regiões anterior e posterior?

OBJECTIVE: To evaluate the transverse constriction of the maxilla in both anterior and posterior regions, using Korkhaus analysis and to check whether there were any statistically significant differences within its values. METHOD: The sample comprised 341 study models. The study models were randomly selected from previous cases, without gender, age and malocclusion restrictions. The models were submitted to Korkhaus analysis. Data from these models were subjected to statistical analyzes in order to evaluate differences in anterior and posterior regions. RESULTS: The transverse discrepancies were statistically significant (p<0.001) with a greater constriction in the anterior region (mean -2.84 mm). CONCLUSION: The results showed that the differential diagnosis is very important and the treatment plan may be adapted to specific therapy focusing in a greater expansion in the anterior region.

OBJETIVO: avaliar a atresia transversa da maxila em duas regiões anatômicas, anterior e posterior, através da análise de Korkhaus, e verificar se há diferença estatisticamente significativa em seus valores. MÉTODOS: a amostra foi constituída de 341 modelos de estudo iniciais, escolhidos aleatoriamente, sem restrições em relação ao sexo, à idade e à má oclusão. Os modelos foram submetidos à análise transversa de Korkhaus e os valores obtidos analisados estatisticamente, para avaliar se as atresias encontradas eram diferentes nas regiões anterior e posterior. RESULTADOS: as discrepâncias transversas são, em média, -2,84mm mais atrésicas na região anterior, sendo essa diferença estatisticamente significativa. CONCLUSÃO: os resultados mostraram que o diagnóstico diferencial é muito importante e devemos adequá-lo aos nossos planos de tratamento e, consequentemente, a uma terapia específica de expansão maior na região anterior.

Preparation and evaluation of orthodontic setup

INTRODUCTION: An orthodontic or diagnostic setup consists in cutting and realigning the teeth in plaster models, making it an important resource in orthodontic treatment planning. OBJECTIVE: The aim of this article is to provide a detailed description of a technique to build an orthodontic setup model and a method to evaluate it. CONCLUSIONS: Although laborious, orthodontic setup procedure and analysis can provide important information such as the need for dental extractions, interproximal stripping, anchorage system, among others.

Efficacy of various spray disinfectants on irreversible hydrocolloid impression materials: An in vitro study.

Background: Most of the materials (casts, impressions, etc.) that are sent to the dental laboratories show the presence of numerous pathogenic microorganisms. All the spray disinfectants are not equally effective against these microorganisms. Aims and Objectives: The aim was to compare the effectiveness of different spray disinfectants on irreversible hydrocolloid impressions and to find out the most effective dilution, contact time, and effect against each microorganism studied. Materials and Methods: The effects of four spray disinfectants, 5.25% sodium hypochlorite, 0.525% sodium hypochlorite, 1:213 (1 part in 213 parts of water) povidone iodine, and 2% glutaraldehyde along with control (distilled water) on irreversible hydrocolloid impressions contaminated with Staphylococcus aureus, Bacillus subtilis and Streptococcus viridans were studied. Results: Sodium hypochlorite, 5.25%, showed 1-min exposure time which was able to effect a 4log10 reduction in bacterial counts against S. aureus and S. viridans followed by 0.525% sodium hypochlorite and 2% glutaraldehyde for 10 min. None were able to effect a 4 log10 reduction against B. subtilis. Conclusion: Sodium hypochlorite with a concentration of 5.25% was the most effective disinfectant and required the shortest contact time (1 min). Not all ADA-approved concentrations of surface disinfectants work equally well on irreversible hydrocolloid impression materials.

Avaliação das alterações dentárias na maxila em pacientes submetidos à expansão rápida da maxila assistida cirurgicamente sem o envolvimento da sutura pterigomaxilar / Assessment of maxillary dental changes in patients submitted to surgically assisted rapid maxillary expansion with no involvement of pterygoid blade

OBJETIVO: avaliar as alterações nos arcos dentários superiores no sentido transversal e a quantidade de inclinações nos dentes de apoio do aparelho de expansão tipo Hyrax em pacientes submetidos à expansão rápida da maxila assistida cirurgicamente (ERMAC) e a efetividade dessa técnica cirúrgica utilizada. A amostra foi composta por 34 pares de modelos de gesso de 17 pacientes, sendo 6 do gênero masculino e 11 do gênero feminino. MÉTODOS: as medidas foram realizadas em modelos de gesso por meio de medição das alterações nos planos vertical e transversal. O procedimento cirúrgico adotado foi uma osteotomia nas paredes laterais da maxila sem o envolvimento da lâmina pterigoide, osteotomia da espinha nasal à linha média dentária (incisivos centrais anteriores), separação da sutura palatina mediana por meio de cinzel e separação do septo nasal. O início das ativações ocorreu no terceiro dia pós-operatório, sendo uma pela manhã e uma à noite. RESULTADOS: houve expansão significativa estatisticamente na região dos caninos, primeiros e segundos pré-molares, primeiros e segundos molares, respectivamente de 6,03mm, 9,82mm, 8,66mm, 9,72mm e 5,67mm. Avaliando o comportamento dos dentes de apoio do disjuntor quanto às inclinações das coroas dentárias, notou-se que ocorreu uma vestibularização assimétrica, pois para os primeiros molares os valores encontrados foram 6,89º (direito) e 9,56º (esquerdo), e para os primeiros pré-molares os valores obtidos foram 4,74º (esquerdo) e 3,26º (direito), sendo esse considerado estatisticamente não-significativo. CONCLUSÕES: a técnica cirúrgica empregada para esta pesquisa mostrou ser eficiente para se obter alteração transversal maxilar, ocorrendo inclinação dentoalveolar dos dentes de apoio do disjuntor.

AIM: To assess the changes to the superior dental arches, in the transversal direction, and the amount of inclinations in the support teeth of the Hyrax expansion appliance in patients who underwent surgically assisted rapid maxillary expansion (SARME), as well as the effectiveness of the surgical technique used. The sample was composed of 34 pairs of cast models, of 17 patients - 6 males and 11 females. METHODS: The measurements were performed on cast models, by measuring the changes on the vertical and transversal planes. The surgical procedure used was the lateral osteotomy on maxillary walls with no involvement of the pterygoid blade, osteotomy of nasal spine on dental midline (anterior central incisors), chisel separation of palatine suture, and separation of the nasal septum. The activation was initiated on the third postoperative day, consisting of two activations, one in the morning and another at night. RESULTS: There were statistically significant expansions in the regions of canines, first and second premolars, first molars, and second molars; respectively, 6.03 mm, 9.82 mm, 8.66 mm, 9.72 mm, and 5.67 mm. The evaluation of the behavior of the support teeth of the expansion appliance regarding the inclination of the dental crowns has shown that an asymmetric vestibularization had taken place, because the values found for the first molars were 6.89º (right) and 9.56º (left); the values for the first premolars were 4.74º (left) and 3.26º (right); this last value was not statistically significant. CONCLUSIONS: The surgical technique used in this research has been shown to be efficient to obtain maxillary transversal alterations, and there was dental-alveolar inclination of the support teeth of the expansion appliance.