Objectives: To investigate the effects of different storage periods of alginate impressions on digital model accuracy. Materials and Methods: A total of 105 impressions were taken from a master model with three different brands of alginates and were poured into stone models in five different storage periods. In all, 21 stone models were poured and immediately were scanned, and 21 digital models were prepared. The remaining 84 impressions were poured after 1, 2, 3, and 4 days, respectively. Five linear measurements were made by three researchers on the master model, the stone models, and the digital models. Time-dependent deformation of alginate impressions at different storage periods and the accuracy of traditional stone models and digital models were evaluated separately. Results: Both the stone models and the digital models were highly correlated with the master model. Significant deformities in the alginate impressions were noted at different storage periods of 1 to 4 days. Alginate impressions of different brands also showed significant differences between each other on the first, third, and fourth days. Conclusions: Digital orthodontic models are as reliable as traditional stone models and probably will become the standard for orthodontic clinical use. Storing alginate impressions in sealed plastic bags for up to 4 days caused statistically significant deformation of alginate impressions, but the magnitude of these deformations did not appear to be clinically relevant and had no adverse effect on digital modeling. (Angle Orthod. 2009;79:30-36.)

Measurements performed on the crib confirm the tongue adaptation to environmental changes. Resting tongue pressures at the 12th month remained lower than the initial values. These findings indicate adaptive behavior of the tongue to open bite closure and the new position of the incisors.

No abstract

An adult male patient who presented with an anterior open bite and a narrow maxilla was treated using a transpalatal distractor (TPD). Transpalatal distraction is a technique for orthopedic maxillary expansion, in which distraction osteogenesis is used. In this technique, the angulation and location of the TPD are critical because they may affect the ratio of skeletal/dental expansion. Any incorrect placement of a TPD may also damage the surrounding blood vessels and premolar roots. This case report introduces a new and easy method for the accurate placement of a TPD using the TPD transporter in an adult patient.