Comparison of the effect of the three disinfectants on dimensional changes of poly vinyl siloxane impression material

Abstract. Background and objective: dimensional changes of impression materials after using disinfectants are one of the mailn problems in dentistry which caused some changes in integrity restoration and as a result failure of treatment. Regarding the importance of microbial disease and possibility of infection transmission to dental personnel, finding out of an appropriate disinfectant, is required. The effect of disinfectants on dimensional stability of impressions has been considered in many studies. The main aim of this study is evaluation of the effect of three disinfectants perform-ID, deconex 53+ and 5.25% sodium hypochlorite solution on dimensional stability of poly vinyl siloxane impression materials. Materials and methods. This study is experimental in which 60 impressions were taken from a master model. These impressions were categorized in 4 groups: first one as control and 3 groups were immersed in 3 disinfectants (5.25% sodium hypochlorite solution, deconex 53+ and perform-ID).After disinfection the cats were made from them and after 24 hours they were measured with profile meter microscope and the results of research were reported after consideration of statistical founds. Results. According to data from ANOVA statistical studies, we found that dimensional changes of perform-ID were 0.0211 ‹ X ‹ 0,0132 in short span, 0,111 ‹ X ‹ 0,122 in long span and (-0,332) ‹ X ‹ (-0,294) in height which was the least dimensional changes in compare with the other two groups. Conclusion. From the results of the study it would inferred that effect of perform-ID on dimensional changes of poly vinyl siloxane impressions was the least against with deconex 53+ and 5.25% sodium hypochlorite solution. So we can use perform-ID for disinfection of poly vinyle siloxane impressions.

Introduction. Dimensional changes following the application of disinfectants, which in turn result in the integrity loss of the restoration and end up in treatment failure, is one of the major problems in fixed partial prosthesis [1]. Concerning the importance of microbial disease and the possibility of cross-contamination between patients and dental personnel, introduction of an appropriate disinfectant seems mandatory. This cross-contamination could happen through direct or indirect exposure to the patients' blood and saliva. Saliva is known as a major source of contamination due to the high bacterial count within (5.5 x 10⁴), so it could readily transfer the microbial contamination [2]. In the United States, 14% to 18% of general dental practitioners, 13% of dental assistants, and 17% of hygienists have shown evidences of HBV contamination [3]. Continuance of lack of necessary knowledge regarding the correct method to disinfect dental impression causes different infections in dental personnel and finally even death [4].

Keen et al., and David G et al., [5] claimed the amount of dimensional changes resulting from poly vinyle siloxane to be 0.4% and 0.3% respectively. According to the studies of Owen, the immersion of impressions in the disinfectant solution for 30 minutes is the most efficient disinfection approach and hydrophobic materials show the least dimensional changes [6]. Jagger et al., found that immersion of impressions in 5.25% sodium hypochlorite solution for 10 minutes is the most efficient way and causes transverse dimensional changes [7]. Through his study, Harrison concluded that the dimensional changes caused by 5.25% sodium hypochlorite solution on poly vinyle siloxane impression material is negligible [8]. According to the studies of luis adabo, it was concluded that perform-Id causes more dimensional changes in poly vinyle siloxane compared to the glutaraldehyde and double ionized water [9]. Yataka, however, reported that poly vinyle siloxane has a relative contration of 0.2% and others have relative dimensional stability [10]. In the studies of Leppe, it was concluded that these changes are about 0.43%, the most amount of dimensional changes compared to the other materials [11]. Credible organizations such as Pasteur institute of iran following several studies approves deconex 53+ as the efficient disinfectant. Yet there have not been any studies concerning the effects of the deconex 53+ on poly vinyle siloxane impression materials [12].

According to the uninvestigated influence of different disinfectants on dimensional changes of poly vinyle siloxane impression materials, the present study aimed to compare the dimensional changes of 3disinfectants, 5.25% sodium hypochlorite solution, deconex 53+, and perform-ID, on poly vinyle siloxane impression material in school of dentistry, azad university of Tehran during 2006-06

Materials and methods. This single/double blind, experimental in vitro study was based on observation and documentation of the obtained data. Experimental model included two, 11mm distant, 5 mm in diameter, 11 mm in height, stainless steel buttresses with the convergence angle of 3 mm.on each side of the terminal part of the metal structure, there was a guiding rod which shows the path of insertion. Superior part includes two holes serving as the metal tray. Metal model was first left in place for 30 minutes to adapt to the room temperature and meet the standard temperature of ISO which is 20 ± 2C [13]. Impergam impression material was mixed according to the instruction of manufacture and placed on the metal tray and the tray was then placed on the dyes. The whole metal structure system was pressed under the pressure of 10 Kg/cm, so that the borders of tray and metal structure became tangent [14]. Tray was dislodged from the dye after the complete setting of the impression material.

Sixty samples were prepared and divided into 4 groups of 15 samples each; 1: without being immersed in any disinfectants, left in placed for 15m as the control samples; 2: fifteen minutes of immersion in perform-ID solution; 3: fifteen minutes of immersion in deconex 53+; and 4: fifteen minutes of immersion in 5.25% sodium hypochlorite. All samples were poured after 5 minutes, casts were removed after 1 hour, and measurements accomplished 24 hours afterwards [9].

Forty eight grams of stone IV (velmix), was mixed with 12 milliliters of tap water. This mixture was stored in vacuum device for 30 minutes and mixed and poured during 3 minutes [14]. All samples were then measured using a profilometer microscope with a resolution of 0.01 mm, twice for each sample and averages considered.

Referenced landmarks:

1. AB, the shortest referenced diameter (short span).
2. AC, the distance between the extreme point on reference dye and the nearest point on the seconds.
3. AD, the distance between extreme points on either dyes (long span).
4. BC, the distance between next/adjacent points on either dyes.
5. DE, the height of reference dye.

Results. Average quantity, standard deviation, and p-value were measured and the normality (goodness of fit) of the data was assessed by Kolmogorov-Smirnov test. It was found that data have normal distribution. Therefore ANOVA test was applied. The amount of dimensional changes with perform-ID 0.86% to 1.06% in the short span, 0.96% to 1.04% in long span and 0.97% to 1.05% in height. These were measured to be respectively 0.76% to 1.24%, 0.95% to 1.05%, and 0.94% to 1.06% with deconex 53+. Dimensional changes with 5.25% sodium hypochlorite were 0.92% to 1.08% in short span, 0.95% to 1.06% in long span, and 0.79%to 1.22% in height. These changes were less than 1.5% and therefore negligible. perform-ID induces the least dimensional changes.

Table1. The amount dimensional changes in the impressions disinfected by the 5.25% sodium hypochlorite, deconex 53+, and perform-ID.

Discussion. In the study, no significant dimensional changes were seen following the disinfection of the impression in perform-ID. Dimensional changes were, however, significant in both long and short spans with the 5.25% sodium hypochlorite solution. Regarding deconex 53+, significant changes were detected in all distances except for height. perform-ID induced the least dimensional changes of all and did not result in any significant changes.

In 1999, Gelson claimed impergam and Coeflex respectively as the weakest and most adaptable disinfectant solutions through a comprehensive study on poly sulfide, poly vinyl siloxane, PVC, and other impression materials. Finally the amount of dimensional changes was measured to be about 39%. According to the recommendation of ADA, less than 50% is negligible. In our study, the amount of dimensional changes was measured not to be significant with perform-ID [9]. In 2004,Jagget et al., compared three impression materials, alginate, poly vinyle siloxane, and additive silicon, disinfected with 4 different solutions and concluded that poly vinyle siloxane experiences expansion-type longitudinal and shrinkage-type transverse changes mostly with the immersion in 5.25% sodium hypochlorite. In our study, we similarly concluded that dimensional changes in long span and short span are significant [7].

In 1995, Yataka et al., claimed a 0.0@ expansion with impergam immersed in perform-ID. In our study, however, changes were of expansion type. These changes were negligible. This may be due to the different immersion times [10]. In 2002, Lepe and Berg used poly vinyle siloxane and additive silicon as impression materials and perform-ID and 2% glutaraldehyde as disinfectant solution and concluded that dimensional change in impergam equals 0.43% which is of contraction type. In our study, we concluded that impergam experiences a negligible expansion while immersed in perform-ID.

This could be due to the different study methods since lepe added surfactant to the impression material before disinfection, which diminishes the hydrophilic characteristics of impression material [11]. Harrison in 2005 concluded through his studies that poly vinyle siloxane impression materials preserv their dimensional stability in 5.25% sodium hypochlorite. However it was revealed through our study that disinfection of poly vinyle siloxane impression materials by this solution results in transverse dimensional changes which could be due to the difference time and method of disinfection. Harrison extended the immersion time to 5 minutes due to the hydrophilic characteristic of poly vinyle siloxans [8].

Compared to the control group, significant dimensional changes occurred in some dimensions with deconex 53+ and 5.25% sodium hypochlorite. These changes may be attributed to the different methods and disinfection characteristics of these materials. Changes due to the immersion in 5.25% sodium hypochlorite may result from the oxygen release in the poly vinyle siloxane 

impression materials. In our study, immersion was preferred to the spraying method since it assures complete wetting of impression surfaces. Study conditions were standardized for all three disinfectants.

It should be noted that, apart from the potential of the disinfectant solutions in dimensional stability preservation, antibacterial effect of the disinfectants is also considered as an important aspect of their efficacy.

This study, however, solely concerned the dimensional stability and does not represent the bactericidal efficacy of disinfectants on studied impression materials.

Conclusion. Based on our findings, it could be concluded that perform-ID induces less dimensional changes compared to the 5.25% sodium hypochlorite and deconex 53+, and could be efficiently used in the disinfection of poly vinyle siloxane impression.

Refrences 

1. Yokota S., Nakata J. Evaluation of dimentional stability of elastometric impression materials during disinfection.Tokio dent.1995, vol 36, chap.9.
2. Zirrec F., Mercle O. Effect of disinfectant agents on dimentional stability of elastomeric impression. J.Prosthodont. 1999, vol. 81, num.13, chap.6.
3. Zuwir l., Gelson J. Wettability, imbibation mess change of disinfected low viscosity impression materials. J.Prosthodont, 2002, vol. 88 num. 26, chap.23.
4. Jeger A., Herison L. The effect of a range of disinfectant on dimentional stability accuracy of some impression materials. Euro J. Prosthodont. 2004, vol. 12, num.4 chap.56.
5. Mac N., Harrisen V. Effect of disinfections on irreversible hydrochloride. J. Prosthodont. 2004, vol. 96, chap. 56.
6. Iran institute pastor, kaivan labrotory. date 29/7/78.
7. Onil Mark. Infection control on dental envirement, mark onil 3th ed Chicago, mosby, 1998.
8. Fenrir G., Larren J. Dimentional stability detail production of irreversible hydro colloid elastometric impressions.Euro J. Prosthodont, 2005, vol.10, chap. 67.
9. M. Powers John, Sakaguchi Ronald. Restorative dental materials John M. Powers, Ronald Sakaguchi, twelfth ed United States of America, 2002.
10. Farro R.J. Accuracy of one step versus two step putty wash adition silicone imperession tech. J. Prosthodont,1999, vol.67.
11. Mishel Martin, Duntis Enriko. Infection control in dental environment. Firth ed Colombia, mac intash, 1991.
12. Farro R.J. Accuracy of one step versus two step putty wash adition silicone imperession tech. J. Prosthodont,1999, vol.67.
13. Mill Ward, Watteres H. Effect of disinfections on wettability of silicon impressions. J. Prosthodont. 2001,vol. 86, chap. 79.
14. Hervera S., Marchant V. Dimentional stability of dental imperession after immersion disinfection. J. Am. Dent.1992, vol.113, num.14, chap.39.

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