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Calcium hydroxide is mainly used for dental pulp capping and it is thought that it induces hard tissue formation far better than other materials. Experimentally verifying this fact, Nishikawa et al revealed that bone-like dentin corresponding to tertiary dentin is rapidly formed when calcium hydroxide is applied directly to the pulp. Utilizing the same experimental system, histochemical study of the newly formed hard tissue (reparative dentin) was carried out and the results thereof were reported. Thick and irregular reparative dentin was formed in the pulp cavity and partial narrowing of the root canal was observed in m-CT. Histopathologically, the irregular reparative dentin increased its thickness obliterating the root canal having a diff erent Azan staining of aniline blue compared to primary dentin. Numerous cellular inclusion bodies were also trapped inside the thick dentin. Furthermore, with Schmorl’s thionine picric acid staining,thick reparative dentin was noted around the pulp cavity and dentin. The dentin was densely stained with picric acid with diff erent staining ability from the surrounding dentin. In addition, it was clearly confi rmed that many cells were trapped in reparative dentin. The results of the experiment suggest that the characteristics of the newly formed reparative dentin is comparable to tertiary dentin.

In general, pulpotomy is evaluated by pathological examination of sacrificed animals at each observing stage. Not only lots of small animals have to devote itself to experimentation, but also the result of research is lacking about the serial observation of an individual experimental animal. The aim of this study was to compare the relative effectiveness of the calcium hydroxide, formocresol and CO 2 laser using the R_mCT ® . Twenty male Wistar rats, 8 weeks of age, were used and imaged in present study. They were serially observed using the R_mCT ® on days 0, 3, 10, 30, 50 after pulpotomy, followed pathohistological examination. The R_mCT ® images revealed that the pulp capping agents were partly absorbed and a hard tissue-like was observed immediately beneath it, especially in the CO 2 laser group. Pathohistological examination showed a hard tissue-like appearance and inflammatory cell infiltration. The R_mCT ® images agreed with pathohistological finding on the days 50 after pulpotomy. Our research suggested that the R_mCT ® has made it possible to scan serial imaging of small animals such as experimental rats under anesthesia. Since its higher resolution enables clear observation of the entire hand of the rat, it is possible not only to compare the effectiveness of each pulpotomy method, but also to serially observe a single experimental animal during the process post-pulpotomy healing, growth, and aging. This study answered well for the animal protective law that to use the least of animal to got the best result.

A massive hemothorax from a ruptured bronchial artery aneurysm (BAA) is very rare. Only 12 cases of ruptured mediastinal BAA have been reported. This case study describes a 77-year-old female with bronchiectasis who presented with anemia, hypertension, hemothorax, and a mediastinal mass. A chest tube was inserted through which 2 liters of unclotted blood was drained from the left pleural cavity. An enhanced computed tomography scan revealed a ruptured 3-cm diameter mediastinal aneurysm of a bronchial artery supplying the left lower lobe. Transcatheter artery embolization (TAE) with multiple microcoils was performed successfully. Although the patient needed a transfusion, the subsequent course was uneventful. In the absence of trauma or other causes for hemothorax and mediastinal hemorrhage, the possibility of a BAA should be considered. TAE is the treatment method of choice as a minimally invasive strategy in patients with ruptured BAA.