Comparison of the asymmetry index determined on digital panoramic radiographic images and on posteroanterior cephalometric images: a retrospective cross-sectional study.

OBJECTIVE: The purpose of this study was to compare the asymmetry index determined on digital panoramic radiographic (PR) images and posteroanterior cephalometric (PACR) images. METHODS: This study included 100 patients whose PR and PACR images were registered in a database. Condylar height, ramus height, and condylar height plus ramus height measurements were measured bilaterally. Condylar asymmetry, ramus asymmetry, and total asymmetry were evaluated. RESULTS: There was a statistically significant difference between the right and left side for all measurements when evaluated on the PR and also on the PACR images (p < 0.01). When calculating the asymmetry index, the resulting condylar asymmetry and ramus asymmetry values did not show significant differences between PR and PACR images. On the other hand, only the presence of total asymmetry showed a statistically significant difference between techniques (p = 0.013). CONCLUSION: Asymmetry indices can be reliably obtained from both PR and PACR images.

Evaluation of the effect of storage time and disinfectant solutions on the dimensional accuracy of impression materials with digital radiography.

BACKGROUND: The dimensional accuracy of impression materials has been evaluated for a long time, but thus far, digital radiography has not been used for this purpose. The dimensional accuracy of impression materials is very important for the final adaptation of dental prostheses. OBJECTIVES: The objective of this study was to evaluate the effects of different disinfectant solutions and storage times on the dimensional stability of different impression materials by means of digital radiography. MATERIAL AND METHODS: Polyether (PE), hydrocolloid (IH), condensation silicone (CS), and addition silicone (AS) materials were used for preparing impressions, taken from an acrylic master model with 2 vertical and 2 horizontal reference points. Water (W), sodium hypochlorite (SH) and a disinfectant solution without aldehyde (Z) were applied on the impressions. Half of the impressions were poured over immediately and half of them - 1 day after. Digital radiography was used to determine the dimensional accuracy of the impression materials. The data was analyzed with a variance analysis and Tukey's multiple comparison test. RESULTS: While PE showed the smallest dimensional changes, IH showed the greatest in all lines. Applying SH and pouring 1 day after caused the greatest dimensional changes in all impression materials. CONCLUSIONS: Different disinfectant solutions and storage times had a different effect on the impressions, but the dimensional changes were clinically acceptable.