Author : Rajat R Khajuria 1
Date of Publication :24th January 2018
Abstract: Introduction: Margin placement is an essential requirement in any fixed restoration as it limits the boundary of the restoration and seals the implant abutment junction for entry of any debris or saliva, thus failing the restoration.2 The marginal fit of the cast restorations is essential for proper functioning, esthetics and success in the oral cavity. The aim of the study is to compare the effect of pattern materials on the marginal gap of cast copings fabricated on titanium implant abutment. Null hypothesis state no difference in pattern materials when tested for marginal fit over implant abutment. Materials& method: Two pattern materials: Inlay wax and Margin wax were used in the present study. And patterns were prepared on titanium Implant model with implants placed at premolar region and at a molar position. Two grooves one at 900 and other at 1800 were made and 20 samples of inlay wax patterns and 20 samples of margin wax patterns were made which were further divided into two subgroups of 10 each of premolar region and molar region respectively Two stage burnout was carried out and casting was done using nickel-chromium alloy. Two points marked at 900 and 1800 were checked at margin level with the help of stereomicroscope and the vertical marginal gap was evaluated. The marginal gap was calculated at 2 points i.e. 900 and 1800. The distance of the line from groove to the outermost margin was calculated at the master die and on all the samples and their differences were recorded. Results: The data collected from all the samples were analyzed using ANOVA and post hoc tests. In intergroup comparison between both the groups, Group 1 recorded more marginal gap (25.40 ± 0.52 μm) than group 2 (19.99 ± 0.39 μm). In intragroup, comparisons between the subgroups, group B (24.13 ± 0.17 μm) recorded more marginal gaps than group A (21.26 ± 0.41 μm). The f value for all the subgroups was calculated as 87.2899 which was significant at p<0.05. Conclusion: Among the materials tested, patterns made of Margin wax proved to have more marginal fit than Patterns made of inlay wax.
- Schwartz IS. A review of methods and techniques to improve the fit of cast restorations. J Prosthet Dent 1986;56(3):279-8.
- Marker VA, Millcr AW, Miller BH, Swepton JH. Factors affecting the retention and fit of gold castings. J Prosthet Dent 1987;57(4):425-30.
- Morey EF. Dimensional accuracy of small gold alloy castings: A brief history and behavior of inlay waxes. Aus Dent J 1991;31(4):302-9.
- Keith SE, Miller BH, Woody RD, Higginbottom FL. Marginal discrepancy of screw-retained and cemented metalceramic crowns on implants abutments. International Journal of Oral and
- Maxillofacial Implants. 1999; 14: 369-378.
- Pelekanos S, Koumanou M, Koutayas SO, Zinelis S, Eliades G. Micro-CT evaluation of the marginal fit of different In-Ceram alumina copings. European Journal of Esthetic Dentistry. 2009; 4:278-292.
- Koupis NS,Vercruysse CWJ, Marks LAM, Martens LC, Verbeeck RMH. Curing depth of (polyacid-modified) composite resins determined by scraping and a penetrometer. Dent Mater 2004;20:908-914.
- Ushiwata O, de Moraes JV. Method for marginal measurements of restorations: accessory device for toolmakers microscope. Journal of Prosthestic Dentistry. 2000;83: 362-366.
- Cahi E, Rosen M, Becker PJ. A comparison of the dimensional stability of three inlay pattern materials. Journal of the Dental Association of South Africa. 1996; 51: 337- 342.
- Christensen GJ. Marginal fit of gold inlay castings. Journal of Prosthestic Dentistry. 1966; 16: 297-305.
- McLean JW, von Fraunhofer JA. The estimation of cement film thickness by an in vivo technique. British Dental Journal. 1971;131: 107-111.
- Glesias A, Powers JM, Pierpont HP. Accuracy of wax, auto polymerized, and light-polymerized resin pattern materials. Journal of Prosthodontics. 1996; 5: 201-205.