Journal of Interdisciplinary Dentistry

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 8  |  Issue : 3  |  Page : 92--95

Comparison of dimensional stability of die stone and die silicone: An In Vitro comparative study


K Prabhu, BC Subashini, B Venkatakrishnan, AS Ramesh 
 Department of Prosthodontics, Adhiparasakthi Dental College and Hospital, Melmaruvathur, Tamil Nadu, India

Correspondence Address:
K Prabhu
Flat No. A-4, Lakshmi Apartments, Meenambal Street, Melmaruvathur - 603 319, Tamil Nadu
India

Abstract

Background: Die silicone is used for making dies for chair side fabrication of inlays and onlays. Die silicone material is user friendly and fast setting but undergoes shrinkage. Aim: To compare the dimensional stability between Die stone and Die Silicone. Methods: A metal die with known dimensions is made. Impressions of the metal die are made with Polyether impression material. Dies are made out of Die Stone and Die Silicone. The Dimensions of the reproduced details are measured and compared. Results: Both Die Stone and Die Silicone produce comparable results. Conclusion: As Die Silicone is made of Polymer, its dimensional stability is a query. But in the study it was found that, they had similar results. With the advantages of fast setting, chipping and abrasion resistance, it would make Die Silicone a more user friendly material of choice for die making.



How to cite this article:
Prabhu K, Subashini B C, Venkatakrishnan B, Ramesh A S. Comparison of dimensional stability of die stone and die silicone: An In Vitro comparative study.J Interdiscip Dentistry 2018;8:92-95


How to cite this URL:
Prabhu K, Subashini B C, Venkatakrishnan B, Ramesh A S. Comparison of dimensional stability of die stone and die silicone: An In Vitro comparative study. J Interdiscip Dentistry [serial online] 2018 [cited 2018 Dec 11 ];8:92-95
Available from: http://www.jidonline.com/text.asp?2018/8/3/92/245894


Full Text



 Clinical Relevance to Interdisciplinary Dentistry



Die silicones are dimensionally accurate, easy to use and cast of prepared tooth can be obtained in a short period of time for any chair side procedures in prosthodontics and aesthetic dentistry.

 Introduction



Die stone has been the most popular material in dentistry for producing dies. To overcome the disadvantages of this material, die silicone materials have been introduced and are reported by the manufacturers to be dimensionally accurate, more abrasion resistant, and stronger than the improved stones.[1]

Provisional crowns and indirect composite acrylic resin inlays are made with flexible die materials. The use of indirect techniques for the fabrication of prosthodontic restorations has become almost universal. The flexible die technique uses an impression of a prepared tooth made with standard impression materials. After applying a separator where indicated, the die is made by pouring the impression with a flexible die material. When set, the die is removed from the impression, and the restoration is then fabricated and finished on the flexible die.[1],[2]

This technique allows an indirect provisional or a definitive restoration to be made without specialized equipment in a single appointment. Although die silicones have been used for the fabrication of provisional restorations, they have not been used for the construction of metal or metal-ceramic restorations due to concerns on dimensional accuracy. The aim of this study is to compare the dimensional stability of die silicone as a duplicating material with die stone.

 Materials and Methods



The method that was followed is as follows:

A master die is made of known standard value [Figure 1]aMaking of special tray [Figure 1]bAn impression is made [Figure 1]cDie is made with both die stone and die silicone [Figure 1]d and [Figure 1]eThe dies are set aside for a stipulated amount of timeAt the mentioned time, the dies are taken and the measurements are made.{Figure 1}

Master die

The master die was prepared as per the dimensions which are as follows:

Height from shoulder margin 12 mmShoulder width 2 mmHeight of the shoulder 2 mmBase diameter 15 mmTaper 7°.

Two mutually perpendicular lines intersecting at the center of the occlusal surface and terminating at their intersections with the occluso axial line angle were scribed into the occlusal surface. Two lines, each in a plane perpendicular to the long axis of the die, were scribed circumferentially into the surface of the axial wall of the die, one line located 1-mm gingival from the occluso axial line angle and the other 1 mm occlusally from the axiogingival line angle. A line was scribed along the vertical axis of the die. This line intersected one of the perpendicular lines crossing the occlusal surface and the two circumferential lines previously scribed into the axial wall.[3],[4]

Making of special tray

The special tray was fabricated using self-cured acrylic resin (DPI– SELF CURE RESIN). Relief holes were given for better flow and adaptability of the material during impression making.[5]

Impression making

The impression of the die is made with the help of alginate impression material – (ZHERMACK TROPICALGIN).

Making the die using die stone

Ten impressions were poured using die stone. Die stone (ULTRAROCK–KALABHAI) is measured with a water powder ratio of 0.18 ml/100 g of die stone. It is mixed under vacuum pressure and poured immediately into respective impressions.

Making the die using die silicone

The remaining 10 impressions were poured using die silicone. Die silicone (DIE SILICONE-VOCO) is supplied in syringe material and injected using gun. Each duplicating material was separated from the metal die after it has set.

Making the measurements

Measurements were taken immediately, after 24 hrs and 48 hrs using a travelling microscope. They were measured from A–B and then from C–D.

Statistics

Descriptive statistics were done to find the mean and standard deviation. The various dimensions of the die silicone and die stone taken over the period were compared to the metal die. Student t-test was performed to compare the values of dimensional stability of the metal to that of die stone.

 Results



When the dimensions of the metal die (AB--6.1520and CD--10.1690) was compared to that of the die stone over a stipulated interval of time, it was found that on AB dimension the stone die changed from 6.2630 to 6.3160 to 6.3290 from immediate pour to 24 h to 48 h, respectively. On comparison, silicone die changed from 5.9110 to 6.4530 to 6.1950 from immediate pour to 24 h to 48 h, respectively.

Similarly, on the CD dimension, the stone die changed from 9.4310 to 9.5800 to 9.5930 from immediate pour to 24 h to 48 h, respectively. On comparison, silicone die changed from 9.0880 to 9.7450 to 9.5690 from immediate pour to 24 h to 48 h, respectively [Table 1] and [Table 2].{Table 1}{Table 2}

On statistically analyzing the data using paired sample t-test, the difference between the stone die and silicone die over a period was not statistically significant [Graph 1].[INLINE:1]

 Discussion



The results of this study revealed that differences in the changes in the dimensions of the die were not statistically significant.

The difference for standard deviation dimension A and for dimension B was 0.05–0.1. These differences should not create large inaccuracies in interabutment distances for fixed partial dentures within a quadrant or major occlusal errors when the complete arch models are mounted on an articulator.[6] The magnitude of the differences in the relative change in dimensions between the die silicone and die stone studied would not be clinically significant when used for the construction of die in master model. Therefore, the results of this study indicated that both gypsum and die silicone materials evaluated will provide a similar degree of dimensional accuracy.[7],[8],[9]

It is difficult to determine the source of these differences. The controlled placement of the impression tray on the master model was standardized, but the effect of the alginate impression material property and its thickness on the study cannot be determined. The alginate impression material was used in the study since thee manufacturer has recommended the use of alginate impression material for die silicone.

Gerrow and Price reported that polyvinyl siloxane die systems were incompatible with polyvinyl siloxane impression materials because the dies failed to separate from the impression. The use of a separating media improved separation, but detail reproduction was compromised.

 Conclusion



Modern materials are produced with better properties to replace older ones. However, a thorough check on the various parameters of daily use is essential. On comparing die silicone with sie stone, it was found that they were both comparable with dimensional stability, that is, the dies may be stored for an extended period without the material losing its dimensional standards. Furthermore, due to its ease of chair-side manipulation and some of its merits such as superior abrasion resistance, die silicone is a bit advantageous than die stone.

Financial support and sponsorship

This study was financially supported by Cinderella Lakshmi Bangaru trust.

Conflicts of interest

There are no conflicts of interest.

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