The Journal of Korean Academy of Prosthodontics (대한치과보철학회지)

The Korean Academy of Prosthodonitics (대한치과보철학회)
권호 표지

COMPARISON OF RIGIDITY AND CASTABILITY IN DIFFERENT DESIGNS OF MAXILLARY MAJOR TITANIUM FRAMEWORK

타이타늄 상악 주연결장치에 디자인에 따른 주조성 및 견고성 비교

  • Lee, Young-Jae (Department of Dental Science, Graduate School, Chonnam National University) ;
  • Vang, Mong-Sook (Department of Dental Science, Graduate School, Chonnam National University) ;
  • Yang, Hong-So (Department of Dental Science, Graduate School, Chonnam National University) ;
  • Park, Sang-Won (Department of Dental Science, Graduate School, Chonnam National University) ;
  • Park, Ha-Ok (Department of Dental Science, Graduate School, Chonnam National University) ;
  • Lim, Hyun-Pil (Department of Dental Science, Graduate School, Chonnam National University)
  • 이영재 (전남대학교 치의학전문대학원 치과보철학교실) ;
  • 방몽숙 (전남대학교 치의학전문대학원 치과보철학교실) ;
  • 양홍서 (전남대학교 치의학전문대학원 치과보철학교실) ;
  • 박상원 (전남대학교 치의학전문대학원 치과보철학교실) ;
  • 박하옥 (전남대학교 치의학전문대학원 치과보철학교실) ;
  • 임현필 (전남대학교 치의학전문대학원 치과보철학교실)
  • Published : 2007.08.31
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Abstract

Statement of problem: Injuries along with discomfort may result on the oral mucosa when non-rigid material is used as the major connector in construction of RPD, since nonrigid major connectors transmit unstable forces throughout the appliance. Titanium which recently draws attention as a substitute of Co-Cr had a difficulty in fabricating due to high melting temperature but the development of casting technique makes it possible to apply to the clinical case. Purpose: The purpose of this study was to investigate the rigidity and the castability of titanium upper major connector by design and make a comparison with Co-Cr major connectors which are widely used in clinical cases now. Material and methods: Casting was done using CP-Ti(Grage 2) (Kobe still Co., Japan) for the experimental groups, and 4 various designs namely palatal strap, U-shaped bar, A-P strap, and complete palatal plate were casted and 5 of each designs were included in each group. For the experimental group, Universal testing machine (Model 4502; Instron, Canton, Mass) was used to apply vertical torsional force vertically to the horizontal plane of major connector. In the second experiment, Vertical compressive force was applied to the horizontal plane of major connector. As a comparative group, Co-Cr major connector was equally manufactured and underwent the same experimental procedures Strain rate was measured after constant loading for one minute duration, and statistical analysis was done with SPSS ver.10.0 for WIN(SPSS. Inc. USA). From the one-way ANOVA and variance analysis (P=0.05), Scheffe's multiple comparison test implemented. Results: 1. Least amount of strain was observed with complete palatal plate followed by A-P bar, palatal bar, and the U-shaped bar having most amount of strain. 2. In all designs of titanium major connector, less strain rate was observed under compressive loading than under torsional loading showing more resistance to lateral force. 3. For titanium major connector, less strain rate was observed when the force is applied to the first premolar area rather than to the second molar area indicating more strength with shorter length of lever. 4. In Comparison of Co-Cr major connector with titanium major connector, palatal strap and U-shaped bar designs showed higher strength under torsional force that is statically significant, and under compressive force, no significant difference was observed expert for U-shaped bar. 5. In titanium major connector, complete palatal plate showed lowest success rate in casting when compared with the Co-Cr major connector. Conclusion: Above results prove that when using titanium for major connector, only with designs capable of generating rigidity can the major connector have almost equal amount of rigidity as Co-Cr major connector and show lower success rate in casting when compared with the Co-Cr major connector.

Keywords

References

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