트레이 접착제의 도포두께에 따른 트레이와 고무인상재의 인장 결합강도

Abstract

[한글]정확한 인상채득을 위해 고무인상재가 많이 사용되고 있지만 트레이접착제의 도포두께가 트레이와 고무인상재의 결합강도에 미치는 영향에 대하여 아직까지 깊이 연구된 바가 없다. 본 연구에서는 트레이접착제의 두께에 따른 인장 결합강도의 관계를 파악하고 보다 높은 인장 결합강도를 얻기 위한 트레이접착제의 도포두께를 제시하기 위하여 세 가지 고무인상재의 접착제 두께 변화에 따른 인장 결합강도를 실험하였다.인상재는 Permlastic？ Regular Set(Kerr Corp., Romulus, Michigan, U.S.A.), ImpregumTM PentaTM(3M ESPE, Seefeld, Germany), 그리고 Aquasil Ultra Monophase Regular Set Smart Wetting？(Dentsply Caulk, Milford, Delaware, U.S.A.)의 세 종류를 선택하였고 각각의 제조사에서 제공되는 트레이접착제인 Impression Adhesives, Polyether Adhesive, Silfix를 사용하였다.자가 중합 트레이 레진(Instant Tray Mix, Lang, Wheeling, Illinois, U.S.A.)으로 24X24X12mm의 시편을 제작하고 내경 16mm, 12.5mm의 PVC pipe를 인상재의 housing으로 사용하였다. 인상재마다 group A에서 9개의 시편을 가지는 5개의 군으로 총 45개, group B에서 20개의 시편을 제작하여 합계 195개의 시편을 제작하였다. Group A에서는 20분 간격을 두면서 트레이접착제를 균일하게 1회에서 5회까지 도포하고 건조시킨 후 spectrophotometer(CM-3500d, Konica Minolta, Sakai, Osaka, Japan)에서 접착면의 명도(L*)를 측정한 후에 인상재를 적용하고 충분한 중합 후에 만능시험기(Instron, model 3366, Instron Corp, Nowood, Massachusetts, U.S.A.)에서 인장 결합강도 시험을 실시하였다. Group B에서는 수회 도포량 두께의 트레이접착제를 한번에 도포하고 15분 후에 인상재를 적용하고 15분 중합 후에 인장 결합강도 시험을 실시하였으며 24시간 후에 인상재와 접촉되지 않은 도포면에서 명도를 측정하였다. 도포횟수와 도표면의 명도 간의 추정 관계식을 group A에서 산출하여 이를 group B에 적용하여 group B의 명도값에 해당하는 도포횟수 추정치를 계산하였다.실험 결과로 다음과 같은 결과를 얻었다.1. Group A의 세 종류의 인상재 모두에서 도포횟수의 증가에 따른 유의성있는 표면 명도값의 감소가 나타났으며 도포횟수를 도포두께의 기준 단위로 사용하는 것이 유효한 것으로 판단되었다.2. Group A에서 Permlastic의 경우 접착제 1회도포시보다 2회도포시에 인장 결합강도의 통계적으로 유의성있는 증가를 보였고 2회도포, 3회도포, 4회도포 간에는 통계적 유의차가 없었으며 5회도포시에 통계적으로 유의성있는 증가를 보였다. Impregum에서는 접착제 3회 도포시까지 인장 결합강도의 통계적으로 유의성있는 증가를 보였으며 3회 이후부터는 통계적 유의차가 없었다. Aquasil에서는 4회 도포시까지 인장 결합강도의 통계적으로 유의성있는 증가를 보였으며 4회와 5회 도포 사이에서는 통계적 유의차가 없었다.3. Group B에서 Permlastic의 경우 도포두께가 증가할수록 인장 결합강도의 감소 양상을 보였고 Impregum에서는 도포두께가 증가할수록 인장 결합강도의 증가 양상을, Aquasil에서는 도포횟수추정치 약 2.5회까지 인장 결합강도가 증가하다가 약 4.5회 이후 급감하는 양상을 보였다.접착제의 두께가 두꺼워질수록 인장 결합강도가 증가하는 경우도 있으므로, 트레이 접착제를 얇게 한겹 도포하는 것이 우수하다는 통념의 수정이 필요하며, 일부 제품 제조사의 지시사항도 재검토되어야 할 필요가 있다.

[영문]Elastomeric impression materials have been widely used to get accurate impression. However, there were not enough studies on the influence of thickness of the tray adhesive to bond strength between tray and elastomeric impression material. In order to understand the relation between the thickness of the tray adhesive and the tensile bond strength and suggest the thickness at which the bond strength is higher levels, tensile bond strength related with the thickness of adhesive of three different elastomeric impression materials was tested.Three impression materials, Permlastic？ Regular Set(Kerr Corp., Romulus, Michigan, U.S.A.), ImpregumTM PentaTM(3M ESPE, Seefeld, Germany), and Aquasil Ultra Monophase Regular Set Smart Wetting？(Dentsply Caulk, Milford, Delaware, U.S.A.), were used in this test, and tray adhesives which were made by the same manufacturer of impression material were used, which were Impression Adhesives, Polyether Adhesive, and Silfix, respectively.The tray specimens with the size of 24X24X12mm were prepared by autopolymerizing tray material(Instant Tray Mix, Lang, Wheeling, Illinois, U.S.A.), and PVC pipe with internal diameter of 16mm, 12.5mm was used to house the impression material. Group A consisted of 5 subgroups which had 9 specimens each, total 45 specimens, and group B consisted of 20 specimens. Therefore, the total number of specimens was 195. In group A, tray adhesive was applied in a multiple thin layers from one to five according to the subgroups, and it was dried for 20 minutes between each application. Additional drying time was given after completion of application of the adhesive. Lightness(L*) of the adhesion surface was measured by spectrophotometer(CM-3500d, Konica Minolta, Sakai, Osaka, Japan). Impression material was applied, and enough time was allowed for polymerization, and tensile bond strength was measured with universal materials testing machines(Instron, Model 3366, Instron Corp, Nowood, Massachusetts, U.S.A.). In group B, adhesive was applied once, in a thickness as same as the thickness of several applications, and each impression material was applied after 15 minutes of drying, and tensile bond strength was measured after 15 minutes of impression material polymerization. After 24 hours, lightness was measured at the surrounding area of the debonded surface. A formula between the numbers of application layers of adhesive and the lightness of adhesion surface was deduced in group A, and the number of application layers of adhesive in group B was estimated by applying the lightness(L*) in the formula.On the test, the following results were drawn.1. Lightness(L*) showed significant decrease according to the increase of application layers of adhesive. Therefore, it was concluded that the numbers of application layers of adhesive could be used as a standard of thickness of adhesive layer.2. In group A, statistically significant increase of tensile bond strength appeared while the number of application layers was increased from 1 to 2 and from 4 to 5, and no significant difference appeared between application layers of 2, 3, and 4 in Permlastic. In Impregum, tensile bond strength was significantly increased when the number of application layers increased from 1 to 3, and no significant difference appeared after 3. In Aquasil, tensile bond strength was significantly increased when the number of application layers increased until 4 and no significant difference appeared between 4 and 5.3. In group B, tensile bond strength was decreased when the thickness of adhesive was increased in Permlastic. Impregum showed increased tensile bond strength when the thickness of adhesive was increased. In Aquasil, tensile bond strength was increased when the number of adhesive application layers was increased until approximately 2.5 and it was sharply decreased after approximately 4.5.By the study, the common idea that it is better to apply a thin single coat of tray adhesive needs correction in more detailed ways, and instructions of some tray adhesive should be reexamined, since there were several cases in which tensile bond strength increased according to the increase of the thickness of adhesive.