支台築造用合金が歯根の変色におよぼす影響
スポンサーリンク
概要
- 論文の詳細を見る
The root discoloration has often been observed in the teeth having post and core. This study was perfomed to identify the constituent elements of the post and core materials responsible for the discoloration through the analysis of the extracted teeth having been discolored in service as well as the in vitro root discoloration test in some corrosive solutions. Some cast dental alloy posts and commercially available prefabricated posts were employed in the in vitro discoloration test. The solutions used were 0.1% sodium sulfide and 1% lactic acid solution, Ringer's solution, artificial saliva, and saline solution. The results obtained were summarised as follows : 1. The root discoloration was observed in 32 extracted teeth out of 125, which had been restored with post and core. 2. It was found from the X-ray microanalysis that the post materials in the discolored teeth were Ag-Zn-Sn alloy, Cu-Zn alloy, Ni-Cr alloy and stainless steel. Especially the use of Ni-Cr alloy showed the most serious discoloration. 3. The root discoloration could generally be classified into two types : one showing light but wide discoloration along the dentin tubules, and the other dark discoloration along the cracks existing in the root. 4. The dissolution of the post and core materials in the corrosive solutions appeared in the order of Cu-Zn alloy>18-8 stainless steel>Ni-Cr alloy>Ag-Zn-Sn alloy>Au-Ag-Pd alloy>Au-Ag-Cu alloy>pure Ti and Ti-6Al-4V alloy. The more the amount of leaching elements, the more the frequency and degree of the root discoloration. 5. From the cast Au-Ag-Cu alloy and Au-Ag-Pd alloy posts, Zn, Cu, Ag and Au were found to leach out in the solution. The amount of Zn detected in the solution was the largest although the Zn content was very small in these alloys. The tooth root was discolored in part in black-brown when these alloy posts were applied. 6. The Ag-Zn-Sn alloy post showed larger leaching of Zn and more risk of root discoloration. The Cu-Zn alloy post showed marked dissolution and the tooth root was widely discolored in light green to black-brown by the formation of copper rust. 7. In the group of prefabricated post, the 18-8 stainless steel and Ni-Cr alloy caused black or black-brown discoloration of the tooth by the marked leaching of their major components, Fe and Ni, respectively. The pure Ti and Ti-6Al-4V alloy, on the other hand, showed little or no dissolution, resulting in no discoloration of the tooth. 8. By casting the Ag-Zn-Sn alloy core onto the prefabricated post, the dissolution of the post and/or core materials was markedly accelerated in a manner of galvanic corrosion except for the Ti and its alloy posts, causing much more discoloration of the tooth.
- 九州歯科学会の論文
- 1993-02-25