engleski

Comparison of arbitrary orientation of casts using photogrammetry

Plaster casts properly oriented in articulators space have great diagnostic meaning. Upper cast should liave the same spatial orientation toward upper part of the articulator, as maxilla have toward referent plane used for face-bow transfer. It is still a matter of discussion, which method for spatial orientation of casts, offers better results. Purpose of this investigation was to: 1. To evaluate photogrammetncally, is there any differences between two mounting methods, 2 To determine any difference in the position of the occlusal planes in articulator space by comparing the two different arbitrary cast orientation methods, 3. To determine are the occlusal planes of the casts parallel regarding two mounting methods. The sample included 40 examenees. Impressions of both jaws were made, and the cast were then mounted in an ARTEX AV 519 articulator, first using Quick - Mount face-bow, and than accordingly to the Bonwill's triangle. Three points on each lower cast were marked, photographed in articulators space and processed photogrammetncaly. The photogrammetric determination of the coordinates of points marked on the castscorrelated with fixed articulator points, produced different position of the points depending on whether one or the other method was used. The results of this study revealed significant difference between the two arbitrary methods of casts orientation (mountings). Using the Bonwill's triangle method, the casts are only approximately oriented in articulators space. Face-bow onentation is much more precise, and the cast are properly orientated toward hinge - axis of the instrument The Face - bow method is recommended for everyday practice.

cast orientation; photogrammetry

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