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Get PDF9784905130062application/pdfEditor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.)boo
Chapter 5 : Deciduous Tooth Resorption after Overfilling of Root Canal Filler: Function and Nature of Multinucleated Giant Cells
Get PDF9784905130062application/pdfThere are numerous reports on physiological root resorption claiming that the root resorption process of primary teeth is regulated in a manner similar to bone remodeling [28]. However, complex histological changes occur under several pathological conditions. Abnormal tooth resorption could be found in primary teeth due to certain causes until the completion of the permanent dentition. In Japan and eastern Asia, calcium hydroxide paste with silicon oil added iodoform is widely used for endodontic treatment of deciduous teeth. This material is sometimes excessively filled within root canals, and pathological reactions have been already discussed in previous sections. In this part, the influences on deciduous tooth endodontic therapy will be described in detail. The most characteristic feature is abnormal tooth resorption via osteoclast-like multinucleated giant cells (MGCs) and foreign body giant cells (FBGCs). In the later part of this section, the characteristics of foreign body type giant cells will be discussed through in vivo experiments.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.)boo
Chapter 6 : Histopathological Studies of Pulpectomy in the Deciduous Teeth of Dogs
Get PDF9784905130062application/pdfA study was performed to examine the impact of resorbable root canal filling material, Vitapex, containing calcium hydroxide and iodoform, on the physiological resorption of its roots, succedaneous permanent tooth buds and periodontal tissues. A total of 14 puppies aged 2-5 months were used; teeth were anesthetized, pulps were extirpated and immediate root canal filling was performed. These procedures were carried out in 53 deciduous teeth with 81 root canals, and contralateral intact teeth were used as controls. The animals were bred for 5 to 60 days and were tracked with radiographical and histological examinations. Results obtained were the following: 1: The form of healing observed after the experimental procedures was divided into 2 groups: those healed either by remaining vital pulp tissue or by the periodontal ligament, with 17 and 29 cases, respectively. 2: The resorption of root canal filling material and the physiological root resorption were almost the same in the majority of cases. 3: The rate of physiological root resorption in the experimental group was slightly delayed compared to that of the control group. 4: The remaining pulp tissue lesions, either in short or long term cases, comprised 5 cases of congestion, 3 cases of hemorrhage, 5 cases of mild inflammation, 11 cases of purulent inflammation, and 1 case of atrophy. 5: Periapical lesions, either in short or long term cases, comprised 6 cases with congestion, 12 cases with mild inflammation, 17 cases with purulent inflammation and 7 cases with pathological alveolar bone resorption. 6: In most cases, the lesions did not significantly affect the permanent tooth buds, except for 6 of 81 cases. 7: Pathological grades obtained in this experiment, in a total of 81 cases, were good in 41 cases (50.6%), fair in 20 cases (24.7%) and a failure in 20 cases (24.7%). 8: The best pathological grades after the experimental procedure were obtained in cases in which the root canal filling material was limited within the canal itself (flush) and in those cases which were underfilled. Overextension of root canal filling should be avoided as much as possible. 9: The relationship between root status and pathological grades showed a slightly lower incidence and favorable results with physiological root resorption compared to those without physiological root resorption. 10: In this study, the use of Vitapex for immediate root canal filling after pulp extirpation in canine deciduous teeth produced good results. Vitality of the remaining pulp and periodontal tissue was restored with subsequent physiological root resorption and without adverse effect on succedaneous permanent tooth buds.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.)boo
食物咀嚼を想定したインプラント支持ブリッジの変形−肉厚・支台間距離の影響−
Get PDFapplication/pdfThe cantilever condition occurring in implant bodies during food−mastication was evaluatedusing JIS type 2 titanium plates of 0.8 (T08), 1.0 (T10), and 2.0 (T20) mm in thickness, according to a method similar to the three−point bending test. A tablet was set in the intermediate area of each titanium plate. The distance between abutment teeth was changed from 10 to 45 mm, load was applied to the tablet using a universal testing machine, and the deflection volume of each plate at the time of tablet fracture was measured. The relationship between the thickness of titanium plates and deflection volume and that between the distance between abutment teeth and deflection volume were compared and evaluated. As a result, during tablet mastication, plastic deformation of T08 occurred when the distance between abutment teeth was 15 mm, and that of T10 occurred when the distance between abutment teeth was 25 mm ; however, plastic deformation of T20 did not occur when the distance between abutment teeth was within 45 mm. Furthermore, when plastic deformation occurred, the deflection volume of the JIS type 2 titanium plate rapidly increased, exceeding the calculated value in the three−point bending test. These results revealed that, when JIS type 2 titanium bridges with a long distance between abutment teeth are set to implant bodies, it is necessary to set their thickness to more than 2 mm. Furthermore, to avoid the cantilever condition in implant bodies, the minimum requirement was considered to be that plastic deformation of the superstructures does not develop during food mastication.journal articl
上顎前歯部インプラント埋入後に歯肉退縮を起こした１症例
Get PDFapplication/pdfRecent reports documented a tissue engineering approach to simultaneously augment hard and soft tissues for implant site preparation in the esthetic zone. A 31−year−old woman presented with an oblique root fracture of the maxillary central incisor, which could not be saved. The treatment plan was to extract the tooth and replace it with an implant. At the time of tooth extraction, guided bone regeneration (GBR) with −TCP granules and a resorbable membrane and a subepithelial connective tissue graft were simultaneously planned for the buccal bone defect. Nine months after extraction, an implant was placed in
the central incisor position, but the bone at the buccal aspect of the implant was thin and v−shaped. Therefore, the buccal bone defect was simultaneously augmented with GBR. Gingival recession occurred at the buccal aspect of the implant, one month after the healing abutment and provisional restoration were placed. Periodontal plastic surgery was performed to correct the marginal mucosal recession at the implant site. A recall visit forty months after implant placement revealed that the implant was maintained well and the soft tissues were stable.journal articl
