Dental arch perimeter changes as a result from premature loss of primary anterior teeth due to trauma: A case series in infant and pre-school children.

BACKGROUND: The premature loss of primary anterior teeth in deciduous arches is a controversial topic in the literature, especially due to the lack of robust scientific evidence about the consequences in the arch perimeter space and magnitudes of the effects involved. AIM: Evaluate the association between premature loss of primary anterior teeth and dental arch perimeter changes, according to clinical variables as deciduous arch type, erupted primary canines, midline involvement and deleterious oral habits, on infants and pre-school children. DESIGN: Patients with avulsion or referral to extraction due to traumatic dental injuries (TDI) were evaluated. After the tooth loss, two trained operators measured the tooth/teeth space, both with a digital caliper and a dry tip compass. The clinical documentation included photographs and radiographs. Follow-up visits occurred from the baseline and every two months over a 12-month period. Chi-square test was used to evaluate the association between arch perimeter changes and clinical variables (α = 0.05). A descriptive statistic was performed to explore the magnitude of space changes, with 95% confidence intervals. RESULTS: Eighteen infants/children (mean, 2.78 ± 1.39 years) were included. Nine patients presented space loss (50.0%) (mean, -1.32 mm), six patients gained space (33.3%) (mean, +1.55 mm), and three patients presented space maintenance (16.7%). Clinical variables did not influence dental arch perimeter changes. CONCLUSIONS: Premature loss of primary anterior teeth, as well as deleterious oral habits, deciduous arch type, midline involvement and erupted primary canines, were not associated with dental arch perimeter changes.

Glossectomy as an adjunct to correct an open-bite malocclusion with shortened maxillary central incisor roots.

A young man, 19 years of age, with the chief complaint of an anterior open bite, came for orthodontic treatment with a skeletal Class I relationship, anterior open bite, shortened maxillary incisor roots, and relative macroglossia. The malocclusion was treated by extracting the maxillary first premolars and using a fixed edgewise appliance. A partial glossectomy was performed before the orthognathic surgery with a 3-piece segmental LeFort I mandibular setback, and advancement was achieved with a reduction genioplasty. A functional and esthetic occlusion with an improved facial profile was established, and the apex of the maxillary left central incisor became slightly rounded after prolonged and significant tooth movement. Four years after treatment, there was occlusal stability of the results, and no further root shortening was observed.

Liberação de flúor dos cimentos ortodônticos: Sumo e Permaband D: estudo in vitro / Fluoride release of orthodontic cements: Sumo e D Permaband: study in vitro

Objetivo: testar a hipótese de que existe diferença significante no desempenho de cimentos ortodônticos entre si quanto à liberação de flúor. Material e Métodos: os materiais foram divididos em três grupos: dois cimentos de ionômero de vidro (CIVs) utilizados para cimentação de bandas ortodônticas: Grupo S (Sumo, OrthoSource) e Grupo P (Permaband D, OrthoSource), e um compósito ortodôntico: Grupo C (Concise, 3M Unitek), como controle. A liberação de flúor foi medida, durante 28 dias (1h, 24h, um, três, sete, 14, 21 e 28 dias), através de eletrodo íon seletivo conectado a um analisador de íons. Os dados foram submetidos aos testes não paramétricos de Kruskal-Wallis e de Mann-Whitney, a um nível de significância de 5%. Resultados: os resultados evidenciaram que os materiais atingiram o pico máximo de liberação de flúor com 24h após presa inicial. Houve diferença estatística dos grupos S e P com o grupo C em todos os tempos avaliados (p < 0,05), e entre os grupos S e P nos tempos de 1h, 24h, um, três, sete, 14 e 21 dias (p < 0,05). Conclusão: a hipótese foi aceita. O CIV convencional Sumo apresentou um desempenho melhor comparado ao CIV reforçado com resina Permaband D. Entretanto, a liberação de flúor de ambos os cimentos foi significativa para o período avaliado.

Objective: to test the hypothesis that is difference in performance of orthodontic cements in terms of their fluoride release. Material and Methods: the materials were divided into three groups: two glass ionomer cements (GIC) used for cementation of orthodontic rings: Group S (Sumo, OrthoSource) and Group P (D Permaband, OrthoSource) and a composite orthodontic Group C (Concise, 3M Unitek) as the control. Fluoride release was measured for 28 days (1h, 24h, one, three, seven, 14 and 28 days), by ion selective electrode connected to an íon analyzer. The data were subjected to nonparametric tests of Kruskal-Wallis and Mann-Whitney, with a significance level of 5%. Results: the results showed that the materials reached the peak of fluoride release after 24 hours after initial set. Statistical difference between the groups S and P, with the group C at all times (p < 0.05), and between the groups S and P at 1h, 24h, one, three, seven and 14 days (p < 0.05), was demonstrated. Conclusion: the hypothesis was accepted. The conventional GIC showed a better performance when compared to Permaband D resin-reinforced cement, however, the fluoride release of both GICs were significant for the study period.

Optical coherence tomography for debonding evaluation: an in-vitro qualitative study.

INTRODUCTION: The purpose of this research was to demonstrate the potential of the optical coherence tomography technique on the evaluation of changes and damages in the enamel structure caused by debonding and cleanup procedures. METHODS: Twin metal and ceramic brackets were bonded to the labial enamel surfaces of 120 incisors; the brackets were debonded 24 hours later. The anterior surfaces of the teeth were scanned, and optical coherence tomography images were captured in 2-dimensional and 3-dimensional modes before and after debonding and cleanup. A commercial spectral domain optical coherence tomography system with a 5-µm axial spatial resolution was used. The system is based on the Michelson interferometer setup. It is connected to a preconfigured personal computer, and the images are captured with a scanner probe that controls the light beam position at the sample. A total of 960 images were evaluated. RESULTS: The analysis of the 2-dimensional and 3-dimensional images obtained with optical coherence tomography allows observation and evaluation of adhesive remnants, enamel damage, and superficial aspects of enamel from different methods of adhesive remnant removal. The 2-dimensional optical coherence tomography analysis allows in-depth observation of the adhesive remnant layer. CONCLUSIONS: Optical coherence tomography can be a powerful tool for academic and clinical applications for the evaluation of debonding procedures.

Avaliação in vitro da citotoxicidade de ligas metálicas utilizadas para a confecção de próteses dentárias / In vitro evaluation of the cytotoxicity of metal alloys used to manufacture dental prosthesis

Metais são amplamente utilizados em procedimentos de reabilitação oral. Esses materiais entram em contato com estruturas biológicas quando utilizados na cavidade bucal e podem desenvolver citotoxicidade. O objetivo deste estudo foi avaliar a citotoxicidade de diferentes ligas metálicas utilizadas para a confecção de próteses odontológicas. Quatro ligas metálicas foram avaliadas: níquel-cromo (grupo 1), cobre-alumínio (grupo 2), cobalto-cromo (grupo 3) e prata (grupo 4). Inicialmente, os corpos de prova foram preparados utilizando uma matriz padronizada e foram imersos em meio de cultura de células durante 24h para a possível liberação de toxinas, sendo então, colocados em contato com os fibroblastos L929 nos períodos de 24 e 48h. A viabilidade celular foi avaliada em espectrofotômetro. Três grupos adicionais foram avaliados: controle de células grupo C+ (controle positivo), corpos de prova em amálgama e C- (controle negativo), fios de aço em contato com as células. Os dados foram submetidos aos testes estatísticos ANOVA e Tukey. Os resultados mostraram citotoxicidade nos grupos 1 (níquel-cromo), 2 (cobre-alumínio) e 4 (prata) após 24h; estes grupos apresentaram diferença estatística significante entre CC (controle de células) e C- (controle negativo) (p<0.05). Após 48h, a citotoxicidade estava ausente no grupo 1. Todavia, os grupos 2 e 4 ainda apresentaram alta citotoxicidade (p<0.05). A liga de níquel- -cromo apresentou citotoxicidade às células fibroblásticas nas primeiras 24h, enquanto a liga de prata e de cobre alumínio apresentou nas 24 e 48h, sendo maior para cobre-alumínio. A liga de cobalto-cromo não apresentou citotoxicidade

Metals are still widely used in oral rehabilitation procedures. These materials are in contact with biological structures when used within the oral cavity and can develop cytotoxic effects. This study aimed to evaluate the cytotoxicity of different alloys used when fabricating dental prostheses. Four alloys were evaluated: nickel-chromium (group 1), copper-aluminum (group 2), cobalt-chromium (group 3), and silver (group 4). Initially, test bodies were prepared using a standardization matrix. Next, the test bodies were immersed in culture media for 24h to release possible toxins. The medium was then placed in contact with L929 cells for 24 and 48h. The cells were then stained and analyzed for viability in a spectrophotometer. Three additional groups were evaluated: control cell group C+ (positive control), consisting of an amalgam test body; and C- (negative control), stainless steel wire in contact with the cells. The data were analyzed by ANOVA and the Tukey test. Analysis of the results verified cytotoxicity in groups 1 (nickel-chromium), 2 (copper-aluminum) and 4 (silver alloy) at 24h. These groups presented statistically significant differences with the CC (control cell) and C- groups (negative control) (p<0.05). After 48h, cytotoxicity was absent in group 1. However, groups 2 and 4 still presented high cytotoxicity (p<0.05). Nickel-chromium alloy presented cytotoxicity for fibroblast cells in the first 24h, while silver and copper-aluminum alloys showed at 24 and 48h, which was greater for copper-aluminum alloy. Cobalt-chromium alloy presented no cytotoxicity

The anterior dental cross-bite: the paradigm of interception in orthodontics / A mordida cruzada anterior: o paradigma da interceptação em ortodontia

OBJECTIVES: To present specific clinical interception procedures instituted to reduce malocclusionseverity on developmental stage. Anterior tooth cross-bite, involving one or two permanent teeth, is acommon form of malocclusion diagnosed in children about 6 years of age. RESULTS ANDDISCUSSION: Various devices can be suggested for single tooth cases, like removable cantilevereddouble-helix apparatus with digital springs, which is one of the most efficient to intercept malocclusion.In the other hand, fixed appliance does not depend on patient’s cooperation and have greater actionpower and liberates more continuous forces. CONCLUSION: Dental anterior cross-bite, involvingone tooth, can be corrected by means of the multi-loop arch wire with a double-helix, even in caseswhere adequate space for alignment is lacking.

OBJETIVOS: Apresentar procedimento de interceptação clínica específica para reduzir aseveridade da má oclusão no estágio de desenvolvimento. O cruzamento anterior, comprometendoum ou dois dentes permanentes, é forma comum de má-oclusão, diagnosticada em crianças emtorno de seis anos de idade. RESULTADOS E DISCUSSÃO: Vários dispositivos podem ser utilizados para casos de cruzamento de um dente apenas, como os aparelhos de duplo hélice emextremo livre, com molas digitais, um dos mais eficientes para interceptar más-oclusões. Poroutro lado, os aparelhos fixos não dependem da colaboração do paciente, tendo maior poder deação e de liberação de forças contínuas. CONCLUSÃO: Os cruzamentos anteriorescomprometendo um dente podem ser corrigidos por meio de arco com dobras múltiplas, comhélice dupla, mesmo em casos onde há deficiência de espaço para o alinhamento.