Introduction and Objective: To analyze if axial loads of 50 N and 100 N, applied on an implant of 3.75 X 10 mm (Conexão-Jaú, SP, Brazil) fixed on the central portion of a prototype of the mandible with and without support base, generate isochromatic fringes of different intensity and ways. Material and methods: The sample was a segment of the mandible with 115 mm in length, 30 mm height,and 12 mm in thickness, from a block of #7 rose wax. This matrix was adapted to a modified articulator in such way that its base could or not keep contact with the lower arm of the articulator, simply by modifying the support axis. An implant was put perpendicular to the segment of the mandible’s body and then the photoelastic model obtained. The healing abutment was screwed to the implant to receive loads from 50 N to 100 N, with the model with or withoutcontact of its base with the inferior arm of the articulator. Results: Alterations in the reflections of the colors was observed when the implants had been submitted to loads of 50 N and 100 N with or without supported base. Conclusion: Based on the results, it can be concluded that during the photoelasticity analyses alterations in the color standards occurred depending on the support of the sample and the applied load.

ResumoO objetivo deste trabalho foi analisar através de método fotográfico, as alterações dimensionais lineares de três marcas de alginato, dois com tempo de presa estendido (Cavex Color Change e Hidrogum 5) e um convencional (Jeltrate dustless), em quatro períodos de tempo (0, 8, 32 e 80 horas). Material e Método: Com base em um modelo superior de uma boca dentada foi obtido um modelo em resina acrílica, que serviu como padrão para a obtenção dos moldes estudados. Sobre os dentes 14, 17, 24 e 27 foram inseridas marcas que serviram como referência de mensuração. Com uma moldeira em resina acrílica confeccionada sobre este modelo, produziram-se cinco moldes para cada marca de alginato, um de cada vez, sendo os mesmos fotografados em estativa e máquina fotográfica Nikon D50, com distância preestabelecida para todas as fotos. As imagens foram mensuradas no programa Corel Draw. Com base nos valores obtidos dos moldes, e do modelo padrão foi possível estabelecer as alterações dimensionais lineares que ocorreram nas três marcas de alginato, nos tempos estabelecidos. Resultados: Não houve diferença estatística significante entre as três marcas de alginato estudadas. Conclusão: Concluiu-se que a estabilidade dimensional linear dos moldes dos três alginatos estudados estão inseridos num nível aceitável para produzir modelos adequados e que não houve diferença estatística significante entre eles. Descritores: Alginatos; Materiais para Moldagem Odontológica; Precisão da Medição Dimensional. AbstractThe objective of this study was to analyze linear dimensional changes of three brands of alginate, two with extended setting time (Cavex Color Change and Hidrogum 5) and a conventional (Jeltrate dustless) in four periods (0, 8, 32 and 80 hours) through photographic method. Material and methods: A model in acrylic resin, which served as the standard for obtaining the molds studied was obtained from a superior dentate mouth . Tags were entered on teeth 14, 17, 24 and 27 and it served as a measurement reference. A acrylic resin tray was used to produce five molds for each alginate, one at a time, photographed in the stand and Nikon D50 camera with predetermined distance for all pictures. The images were measured in Corel Draw program. Based on the values obtained from the molds, and the standard model was possible to establish the linear dimensional changes that have occurred in the three brands of alginate, at the appointed times. Results: There was no significant statistical difference between the three alginate brands studied. Conclusion: It was concluded that the linear dimensional stability of the molds of the three studied alginates are inserted at an acceptable level to produce appropriate models and that there was no statistically significant difference between them. Descriptors: Alginates; Dental Impression Materials; Dimensional Measurement Accuracy. ResumenEl objetivo de este estudio fue analizar a través del método fotográfico, lãs alteraciones dimensionales lineales de tres marcas de alginato, dos con tiempo de fraguad...

<p><strong>Introduction:</strong> The dimensional alterations of denture base jeopardize adaptation and retention associated to altered occlusion, which are considered relevant factors for fabrication of complete dentures. <strong>Objective</strong>: The aim of this study was to evaluate linear tooth displacement during processing of maxillary complete dentures submitted to two inclusion methods and conventional polymerization. <strong>Material and method</strong>: Twenty maxillary complete dentures were fabricated: G1 – inclusion with silicone barrier, and G2 – inclusion with dental stone type IV barrier. Points were marked on incisal surface of right central incisor and cusp of second molars to allow linear measurement of the replicas through the software AutoCAD. The evaluation of artificial teeth displacement for both groups was carried out in different moments: a) waxed denture; b) waxed denture partially invested with stone or silicone barrier; c) after complete flasking; d) denture into flask after polymerization; e) denture attached to the cast after deflasking; f) denture separated from the cast; g) denture after finishing and polishing; h) denture after storage in water at 36° during 7 days. <strong>Result</strong>: Linear alterations occurred on artificial teeth positioning for both groups and in all periods of inclusion, with higher alterations for group G2. The data from phases c and d were significant different from other phases when compared intra groups, for both inclusion methods evaluated. <strong>Conclusion</strong>: Group G2 exhibited the greatest alterations. After polymerization, group G1(Inclusion with silicone barrier complemented with dental stone type III) demonstrated higher distance between the points (expansion) while group G2 revealed reduced distance (contraction). </p>

To analyze if axial loads of 50 N and 100 N, applied on an implant of 3.75 X 10 mm (Conexão-Jaú, SP, Brazil) fixed on the central portion of a prototype of the mandible with and without support base, generate isochromatic fringes of different intensity and ways. Material and methods: The sample was a segment of the mandible with 115 mm in length, 30 mm height, and 12 mm in thickness, from a block of #7 rose wax. This matrix was adapted to a modified articulator in such way that its base could or not keep contact with the lower arm of the articulator, simply by modifying the support axis. An implant was put perpendicular to the segment of the mandible’s body and then the photoelastic model obtained. The healing abutment was screwed to the implant to receive loads from 50 N to 100 N, with the model with or without contact of its base with the inferior arm of the articulator. Results: Alterations in the reflections of the colors was observed when the implants had been submitted to loads of 50 N and 100 N with or without supported base. Conclusion: Based on the results, it can be concluded that during the photoelasticity analyses alterations in the color standards occurred depending on the support of the sample and the applied load.