リライニング時における義歯床の変形に関する基礎的研究

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In our clinic, dynamic impression technique is used for finished denture in order to record the physiologic mucous membrane, and relining technique is followed. The material used for relining is acrylic resin, so deformation may occur with this technique. In this report, a series of experiments was described with comparison of deformations as produced in the relining process of different procedures. The results were as follows. 1. When rectangular Acron test specimens (10×50×2mm) were relined with Acron, shrinkage of about 0.38% for relinig thickness of 2.0mm, about 0.24% for 1.0mm, and about 0.20% for 0.5mm occurred immediately after polymerizing. Convex deformation to the relinig side of 0.23×10^<-3>, 0.19×10^<-3>, and 0.15×10^<-3> also occurred respectively. 2. When Acron rectangular test specimens were relined with Repairsin, shrinkage of about 0.19% for relining thickness of 0.2mm, about 0.15% for 1.0mm, and about 0.12% for 0.5mm occurred immediately after polymerizing. Convex deformation to the base side of -0.18×10^<-3>, -0.34×10^<-3>, and -0.09×10^<-3> also occurred respectively. 3. When the relined test specimens were immersed in water at 25℃, those relined with Acron intensified the convex deformation to the relining side, whereas those relined with Repairsin reversed the curvature in two to five days. Repairsin is polymerized without heating and this causes convex deformation of the specimens to the base side (due to polymerization contraction). This deformation is considered to evert gradually along with releasing of the stress after removal of the specimens from the mould. 4. Adaptability of relining was examined with use of experimental notched specimens. In all pieces examined, resin and metal came in contact with each other on the incline and spacing on the plane occurred between them. This situation appears to reflect the conditions at the molars of the upper dentures and is suggestive of the possibility of collision of the denture with the maxillary tuberosity. 5. In both rectangular and notched specimens, the degree of deformation of self-curing resin was less than that of the materials (Acron, Quick Acron) which require heating for polymerization. In each kind of material, deformation was less in proportion to the thickness of relining. 6. The approximate water absorption volume percent was 1.52% for Acron, about 3.98% for Quick Acron, and 6.83% for Repairsin. The approximate specific volume was 0.837cm^3/g for Acron, 0.845cm^3/g for Quick Acron, and 0.849cm^3/g for Repairsin. The water absorption volume percent of Repairsin was two to four times that of the other materials. This means that Repairsin has a high risk of discoloration and deterioration because of its porosity. 7. Considering the anterior side of the denture as part of a circle, changes in curvature of the circle at Acron polymerization was examined with use of semicircular test specimens. The arc found to expand outward. This tendency further increased in the test pieces immersed in water. 8. When model mandibular dentures were polymerized with Acron, an terminal expansion of about 0.25% at the posterior end was observed immediately after polymerizing. When they were polymerized with a lateral expansion restrainer-bar attached, an expansion of about 0.08% immediately after removal of the bar occurred, and a maximum of about 0.21% in the specimens immersed in water after removal of the bar. 9. Acron mandibular dentures relined 0.5mm thick with Acron or Repairsin were compared with those relined with the same material and a bar attached. Deformation in those with a bar attached was limited to half.
九州歯科学会の論文
1981-09-25

リライニング時における義歯床の変形に関する基礎的研究

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