The purpose of this study was to conduct load-bearing tests on dual-structured CAD/CAM restoration with fiber-reinforced composite resin for posterior fixed partial dentures (FPDs), and to determine a suitable framework design for them.

 Three-unit FPDs were fabricated on the metal model which simulated loss of right mandibular second premolar. The model was scanned with a laboratory scanner, and the FPDs were designed on the scanned data. FPDs were designed with common external form, and three types of frameworks with different connector thickness were designed; T15: 1.5 mm, T25: 2.5 mm, and T35: 3.5 mm. As a control group, the monolithic FPDs were fabricated by milling HC disk (HC-FPD). Dual-structured FPDs (DS-FPDs) were fabricated by bonding a milled TRINIA framework and a HC veneer. Maximum load to failure and first cracking load were measured with a universal testing machine.

 In the DS-FPDs, the maximum load to failure and the first cracking load were higher than in the HC-FPDs. There were significant differences in the first cracking load between the HC-FPDs and the DS-FPDs (T25 and T35).

 From our results, it was suggested that the DS-FPDs with over 2.5 mm connector thickness were more suitable for posterior FPDs in comparison with the HC-FPDs.

 The purpose of this study was to assess the usefulness of reconstructed panoramic images using CBCT in mixed dentition. Panoramic images were reconstructed from CBCT images and compared with conventional panoramic radiograms of 91 patients who underwent CBCT study for orthodontics treatment.

 All images were evaluated by examining six teeth: the first molars and the right upper and lower middle incisors, and four tooth germs: the second premolars. Six teeth were evaluated for visibility of the crown, alveolar crest, root apex, pulp cavity, and periodontal ligament space. Four tooth germs were evaluated for visibility of the crown and root. All these were given a score on a 5-point scale.

 The Mann-Whitney U test was used to determine the significance of differences between the imaging modalities, with p-values of < 0.05 considered statistically significant.

 It was found that reconstructed CBCT panoramic images are a useful diagnostic tool in clinical situations.

 Regarding a newly developed KZR-CAD Zirconia Gradation (YAMAKIN), which is a multilayer type zirconia for dental milling, based on the concept of natural color tone change, we evaluated the color translucency parameter, contrast ratio and color changes between layers. We also evaluated the changes of the same characteristics when dyed by a dyeing solution. Although the color tone changed deeply from the incisal layer to the cervical layer, the translucency parameter and the contrast ratio were uniform. The degree of coloration of each layer by dyeing did not depend on the shade color or the thickness of the zirconia specimen, or the shade color of the dyeing solution, and the uniform characteristics of the translucency parameter and contrast ratio were maintained.