Quanto de desvio da linha média dentária superior ortodontistas e leigos conseguem perceber? How much upper midline deviation orthodontist and lay people can note?

OBJETIVOS: avaliar o grau de percepção do desvio de linha média superior e da angulação incisal do arco superior entre ortodontistas e leigos, assim como a influência da visualização clínica do filtro labial como referência morfológica para esse diagnóstico. MÉTODOS: foi utilizada a fotografia do sorriso de um indivíduo do gênero feminino, na qual foram produzidas alterações na linha média dentária, de 1 em 1 milímetro, até 4mm, e na angulação incisal, de 5 em 5 graus, até 15 graus, ambas para o lado esquerdo, com o auxílio de um programa de manipulação de imagens (Adobe Photoshop 7.0®).As imagens obtidas foram recortadas,formando um grupo com e outro sem a visualização do filtro labial e,em seguida,foram organizadas aleatoriamente e avaliadas por 24 ortodontistas e 24 indivíduos leigos com nível superior. RESULTADOS: os resultados obtidos revelaram que os ortodontistas foram capazes de detectar desvios da linha média a partir de 2mm (p < 0,05) e da angulação incisal a partir de 5 graus (p < 0,05), enquanto leigos só detectaram como inaceitáveis desvios a partir de 3 ou 4mm (dependendo da presença do filtro labial na imagem analisada) e 10 graus de alteração angular dos incisivos. A visualização do filtro labial na fotografia influenciou, embora suavemente, somente a avaliação dos examinadores leigos. CONCLUSÕES: conclui-se, portanto, que ortodontistas são mais críticos a pequenas variações da linha média superior e da angulação incisal do que indivíduos leigos,e que a visualização do filtro labial superior tem importância secundária como elemento de diagnóstico do desvio da linha média superior para leigos.<br>AIM: The present study evaluated the perception degree of the upper midline deviation and crown incisor angulation among orthodontists and lay people, as well as the influence of the labial philtrum visualization as a morphological reference of the facial midline during smile examination. METHODS: in a smile picture taken from a 23 year old female, 10 year after orthodontic retention, changes were made in the upper midline, from 1mm to 4mm, and in the crown incisor angulation, from 5º to 15º, both for left side, using a image manipulation software (Adobe Photoshop 7.0). The pictures were cut out forming a group with and another without the visualization of the labial philtrum. The images obtained were examined by 24 orthodontists and 24 graduated lay people. RESULTS: Results showed that orthodontists were less tolerant to discrepancies of midline than lay people, as well as to changes in the crown incisor angulation. The orthodontists were able to observe midline deviations of 2mm and crown incisor angulation deviations starting from 5º. The lay people examiners considered as unacceptable only midline deviations starting from 3 or 4mm, depending on the labial philtrum visualization, and angulation deviations of the incisor crown starting from 10º. Labial philtrum visualization had influenced only to lay people examiners. CONCLUSIONS: It can be concluded that orthodontists are more critic when examining midline deviations and crown angulation changes than lay people examiners. The visualization of the philtrum has no influence for the orthodontist group, but had slight influence on the lay people examiners

Influence of a proximal margin elevation technique on marginal adaptation of ceramic inlays

PURPOSE: Evaluating the effect of a proximal margin elevation technique on marginal adaptation of ceramic inlays. METHODS: Class II MOD-cavities were prepared in 40 human molars and randomly distributed to four groups (n = 10). In group EN (positive control) proximal margins were located in enamel, 1 mm above the cementoenamel junction, while 2 mm below in groups DE-1In, DE-2In and DE. The groups DE-1In, DE-2In and DE simulated subgingival location of the cervical margin. In group DE-1In one 3 mm and in group DE-2In two 1.5 mm composite layers (Tetric) were placed for margin elevation of the proximal cavities using Syntac classic as an adhesive. The proximal cavities of group DE remained untreated and served as a negative control. In all groups, ceramic inlays (Cerec 3D) were adhesively inserted. Replicas were taken before and after thermomechanical loading (1.200.000 cycles, 50/5°C, max. load 49 N). Marginal integrity (tooth-composite, composite-inlay) was evaluated with scanning electron microscopy (200×). Percentage of continuous margin (% of total proximal margin length) was compared between groups before and after cycling using ANOVA and Scheffé post-hoc test. RESULTS: After thermomechanical loading, no significant differences were observed between the different groups with respect to the interface composite-inlay and tooth-composite with margins in dentin. The interface tooth-composite in enamel of group EN was significantly better compared to group DE-2In, which was not different to the negative control group DE and DE-1In. CONCLUSION: Margin elevation technique by placement of a composite filling in the proximal box before insertion of a ceramic inlay results in marginal integrities not different from margins of ceramic inlays placed in dentin

Resistência de união entre dentes artificiais e resinas acrílicas para base protética Shear bond strength between artificial acrylic resin teeth and denture base resins

A resistência de união entre dente artificial e resina acrílica para base protética foi avaliada sob a influência de duas marcas comerciais de dentes artificiais (Biotone e Trilux) e de três resinas acrílicas, sendo duas polimerizadas convencionalmente em banho de água (QC-20 e Lucitone 550) e uma resina polimerizada por meio da energia de microondas (Acron-MC). As avaliações foram realizadas por meio de um ensaio mecânico de cisalhamento através da aplicação de uma carga perpendicular à interface dente-resina. Os resultados indicaram que, para a mesma resina, a resistência foi semelhante, independentemente do tipo de dente utilizado. Para os dois tipos de dente avaliados, as resinas Acron MC e Lucitone 550 apresentaram valores de resistência de união entre dente artificial e resina acrílica estatisticamente semelhantes e superiores em relação à resina QC-20.<br>Shear bond strength between artificial acrylic resin teeth and denture base resin was evaluated under the influence of two brands of artificial teeth (Biotone and Trilux) and three denture base resins. Two of these resins were conventionally polymerized in water bath (QC-20 and Lucitone 550), while the other was a microwave-polymerized resin (Acron-MC). The evaluations were done by means of a shear bond strength test with application of a perpendicular load to the interface tooth-resin. The results showed that, for the same denture resin, the strength was similar regardless of the tooth brand. Also, for the two evaluated brands of tooth, the resins Acron MC and Lucitone 550 presented similar shear bond strengths, which were statistically higher than for resin QC-20