This study was performed to observe the influence of the root canal filling materials of the root resorption of deciduous teeth. The root canal filling materials used in this study were Calvital, Kri 1, Kurosu's formula TypeⅡ (zinc oxide-eugenol paste), and Obturation Gutta.

  1) Calvital showed the best histopathological result. The remaining materials in the order of good results were Kri 1, Kurosu's formula, and Obturation Gutta. Experimental roots evaluated as “poor” cases increased in number in the last stage of the root resorption.

  2) Calvital : The resorption of root tissues almost corresponded with that of root filling materials.

  3) Kri 1 : Most of the root filling materials were resorbed after the root tissues were resorbed, though the apices were scarcely resorbed.

  4) Kurosu's formula : The root filling materials were slightly resorbed after most of the root tissues were resorbed, though the root apices were scarcely resorbed.

  5) Obturation Gutta : The root tissues were slightly resorbed on the entire root surface, but the filling materials were scarcely resorbed. Broken pieces of root filling materials made by the eruption of the permanent successor were sometimes found around the opposite side.

  6) The speed of the root resorption in the experimental teeth was gradually delayed after the middle stage. This tendency was more marked in Kurosu's formula and Obturation Gutta than in Calvital and Kri 1.

  The purpose of this study was to evaluate the effect of following four obturation methods for root canals ; lateral condensation of gutta-percha point with CANALS, AH 26, and CHLOROPERCHA as a root canal sealer, and vertical condensation of sectional method using gutta-percha point with CANALS as a root canal sealer.

  1,286 teeth were filled with each techniques, and were examined clinically and radiographically from 1 to 3 years after root canal filling.

  The results were summarized as follows :

  1. According to the clinical and reontgenographic inspection, the success rate of the CANALS group was 81.7%, the AH 26 group was 88.5%, the CHLOROPERCHA group was 76.5%, and the VERTICAL group was 88.4%.

  2. In flush filling cases, the VERTICAL group and the CANALS group were significantly superior to the other group in pulpectomy cases, and the CHLOROPERCHA group was significantly inferior to the others in infected root canal treatment cases.

  3. In each group, flush filling cases were more successful than under and over filling cases.

  4. No significant difference in success rate was found among 1, 2, and 3 year prognosis in any techniques.

  5. Large root canals like maxillary front teeth tend to be overfilled in the CHLOROPERCHA group. Such cases were inferior to the others.

  We tested 95 single rooted teeth in vitro to evaluate the apical seal produced by 1) lateral condensation method with chloroform-softened primary cone and sealer, 2) 1)＋ultrasonic condensation, 3) Opian carrier method, 4) Opian carrier method with sealer, 5) 4)＋ultrasonic condensation, 6) Automated thermatic condensation technique (McSpadden compactor) without sealer, 7) Automated thermatic condensation technique (McSpadden compactor) with chloroform-softened primary cone and sealer.

  The obturated teeth were immersed in indian ink, decalcified and cleared.

  The results showed that :

  1) The lateral condensation method with chloroform-softened primary cone and sealer didn't produce satisfactory apical seals which we were able to obtain by ultrasonic condensation (P＜0.01).

  2) Opian carrier method without sealer had a low sealing property. On the other hand, using both Opian carrier method with sealer and Opian carrier method with sealer＋ultrasonic condensation, we were able to obtain highly satisfactory results (P＜0.005).

  3) Automated thermatic condensation technique (McSpadden compactor) with sealer gave better results (P＜0.005) than without sealer in periapical sealing.

  Finally, ultrasonic condensation was effective to obtain apical sealing with the lateral condensation method. An apical sealer was necessary to avoid apical leakage with Opian carrier method and the automated thermatic condensation technique (McSpadden compactor).

  We succeeded to observe the inner space of canal system by the use of endoscope with Selfoc lens which had been developed recently in Japan. The endoscope used commonly has a rather wide terminal, so it has been impossible in the past to use the endoscope for observation of canal system of dentition. Recently, however, the endoscope with finner terminal could be produced in our country. On the other hand, the canal preparation by the turbine burr has become a popular operation to remove perfectly the debris from the canal system in the dentosurgical work, and as the consequence of this operation, it makes readily to shape the canal system more straight and wide. It allowed to apply the endoscope in this field of dentistry.

  The endodontic therapy is dependent most on a sense and experiences of the dentists till now. It will confirm this therapy more safe and reliable that the inner of canal system can be visible by the use of endoscope.

  Because of the proximity of the maxillary molars and maxillary sinus, treatment of the maxillary molar can be considered successful only when the maxillary sinus is unaffected by treatment. Care must be taken to avoid affecting the maxillary sinus by the lesion. On the other hand, if the maxillary sinus is already affected, the interdiciplinary approach including oral surgery or otorhinolaryngology is recommended.

  A case of cystectomy treatment and simultaneous dental root amputation from the maxillary sinus of a patient (female, 36 yrs. old) with “post operative maxillary cyst” is reported. She was recuperating satisfactorily and advancement of calcification in the periapical region of the amputated root was observed. Further-more it is believed that both the tooth and its peripheral region were recovering to the normal healthy state.