The influence of protective varnish on the integrity of orthodontic cements.

OBJECTIVE: The aim of the present study was to assess the influence of saliva contamination over the structural strength and integrity of conventional glass-ionomer cements used for cementing orthodontic bands in the absence and presence of a surface-protecting varnish. METHODS: 48 samples were prepared by inserting 3 types of glass-ionomer cements into standardized metallic matrixes with 10 mm of diameter and 2 mm of depth. The cements used were: Meron (VOCO), Ketac-Cem (3M ESPE) and Vidrion C (DFL), all of which comprised groups A, B and C, respectively. Subgroups A1, B1 and C1 comprised samples with no surface protection, whereas subgroups A2, B2 and C2 comprised samples of which surface was coated with Cavitine varnish (SS White), after cement manipulation and application, in order to protect the cement applied. All samples were stored in artificial saliva for 24 hours at 37°C. A Vickers diamond micro-durometer was used to produce indentations on the non-treated group (non-varnished) and the treated group (varnished). RESULTS: Varnished materials had significantly higher microhardness values in comparison to non-varnished materials. Ketac-Cem had the highest microhardness value among the varnished materials. CONCLUSIONS: Varnish application is necessary to preserve the cement and avoid enamel decalcification. Glass-ionomer cements should be protected in order to fully keep their properties, thus contributing to dental health during orthodontic treatment.

The influence of protective varnish on the integrity of orthodontic cements

OBJECTIVE: The aim of the present study was to assess the influence of saliva contamination over the structural strength and integrity of conventional glass-ionomer cements used for cementing orthodontic bands in the absence and presence of a surface-protecting varnish. METHOD: 48 samples were prepared by inserting 3 types of glass-ionomer cements into standardized metallic matrixes of 10 mm of diameter and 2 mm of depth. The cements used were: Meron (VOCO), Ketac-Cem (3M ESPE) and Vidrion C (DFL), all of which comprised groups A, B and C, respectively. Subgroups A1, B1 and C1 comprised samples with no surface protection, whereas subgroups A2, B2 and C2 comprised samples of which surface was coated with Cavitine varnish (SS White), after cement manipulation and application, in order to protect the cement applied. All samples were stored in artificial saliva for 24 hours at 37ºC. A Vickers diamond micro-durometer was used to produce indentations on the non-treated group (non-varnished) and the treated group (varnished). RESULTS: Varnished materials had significantly higher microhardness values in comparison to non-varnished materials. Ketac-Cem had the highest microhardness value among the varnished materials. CONCLUSION: Varnish application is necessary to preserve the cement and avoid enamel decalcification. Glass-ionomer cements should be protected in order to fully keep their properties, thus, contributing to dental health during orthodontic treatment.

OBJETIVO: avaliar a influência da contaminação salivar na resistência estrutural e integridade de cimentos de ionômero de vidro convencionais utilizados para cimentação de bandas ortodônticas na ausência e na presença de um verniz protetor de superfície. MÉTODOS: quarenta e oito corpos de prova foram confeccionados a partir de três cimentos ortodônticos, com auxílio de matrizes metálicas padronizadas com 10mm de diâmetro e 2mm de altura. Os cimentos utilizados foram: Meron (Voco), Ketac-Cem (3M ESPE) e Vidrion C (DFL), compondo os grupos A, B e C, respectivamente. Metade dessas amostras não recebeu nenhum tipo de proteção superficial, constituindo os subgrupos A1, B1 e C1, enquanto, os subgrupos A2, B2 e C2 tiveram suas superfícies isoladas com verniz Cavitine (SS White) após manipulação e aplicação do cimento, com intuito de proteger a superfície do cimento. As amostras foram armazenadas em saliva artificial por 24 horas a 37ºC. Foi realizado um ensaio de microdureza (Vickers) para avaliação da dureza de superfície do grupo não-tratado (sem isolamento) e do grupo tratado (agente protetor). RESULTADOS: os materiais previamente isolados com o verniz obtiveram valores de microdureza significativamente maiores que os não-isolados. O cimento Ketac-Cem apresentou, estatisticamente, a maior microdureza entre os materiais protegidos. CONCLUSÃO: o isolamento com verniz mostrou-se necessário para preservação do cimento e, consequentemente, de sua capacidade de evitar possíveis desmineralizações dentárias. Os cimentos de ionômero de vidro devem ser protegidos para manutenção de sua integridade, contribuindo para saúde dental durante o tratamento ortodôntico.

Ectopia and partial transposition of mandibular lateral incisors in a child patient.

Dental ectopia is a rare clinical finding characterized by a change in the normal tooth eruption pathway. In more severe cases, nontreated ectopia may develop into either partial or total transposition. The early diagnosis is of crucial importance for establishing a treatment planning correctly. Therefore, the present paper is aimed at reporting an unusual case of a 11-year-old boy with ectopic eruption and partial transposition of mandibular permanent lateral incisors as well as the diagnosis and therapeutic outcomes involving such an anomaly.

Orthodontic correction of a maxillary canine-first premolar transposition.

Transposition is a form of ectopia, in which 2 adjacent teeth change positions in the dental arch or 1 tooth develops in a position occupied by a nonadjacent tooth. Transposition can be partial or complete. Despite their low prevalence in the general population, transpositions are a challenge to orthodontists, especially if treatment aims to correct the order of the teeth. This article reports the diagnosis, planning, and treatment of a unilateral maxillary canine-first premolar transposition in a female patient treated orthodontically without premolar extraction and with correction of the transposition. Treatment options, advantages and disadvantages of each method, and the mechanics used during the treatment are also discussed.

Alterações superficiais provocadas em fios retangulares de aço inoxidável por alicates de diferentes pontas ativas: estudo em microscopia eletrônica / Surface alterations in stainless steel rectangular wires provoked by orthodontic pliers with different active tips: a SEM study

O presente estudo teve por objetivo avaliar, em microscopia eletrônica de varredura (MEV), os efeitos produzidos na superfície de fios de aço inoxidável retangulares de 0,019x0,026 polegadas por alicates ortodônticos número 442 com diferentes materiais componentes na ponta ativa, o aço martensítico e a vídia (carboneto de tungstênio). Para isso, foram simuladas nos fios dobras de primeira e terceira ordens, de modo que os alicates apreendessem o fio nas suas quatro faces. Os fios trabalhados mecanicamente foram analisados ao microscópio em aumentos de 50, 100, 150, 250 e 500 vezes. Observou-se que os alicates com ponta ativa em aço martensítico provocaram poucas mossas na superfície dos fios, enquanto os alicates com ponta ativa em vídia produziram alterações superficiais marcantes, havendo diferença estatisticamente significativa entre esses dois materiais. Com a metodologia aplicada, foi possível concluir que os alicates com ponta ativa de vídia tendem a produzir mossas na superfície dos fios de aço após trabalho mecânico simulando aplicações clínicas da Ortodontia, enquanto os alicates com ponta ativa de aço martensítico marcam menos a superfície dos fios metálicos.