ORIGINAL RESEARCH ARTICLE

An In Vitro Study of the Effects of Disinfectants and Wetting Agent on the Wettability of Addition Polymerized Silicone Impression Materials and Void Formation in Dies

Santhosh Kotian, Narendra.P.Patil, Lekha.K

Abstract  

Background and Objectives: Polyvinyl siloxane impression materials, besides their excellent physical properties, have known to be variably hydrophobic, which has resulted in poor wettability and in an increased number of voids in gypsum casts. Disinfection procedures and surfactants have been known to affect the wettability of these impression materials. Hence, this study was conducted to evaluate the effects of various disinfectants and wetting agent on the wettability of various addition polymerised silicone impression materials and its correlation with void formation in dies. Method: Putty and light body consistencies of three different hydrophilic addition silicone impression materials namely Aquasil, Affinis and Express were selected. Sixty discs and 60 impressions of each material were made. The respective groups of samples were subjected to Cadicide and Cadidine disinfectant solutions and Aurofilm topical surfactant. The contact angle measurements were made using a Rame-Hart goniometer. Casts were examined using their magnified images on a computer screen and voids in the cross-hatched surface of the casts were counted and noted. The values of contact angle and number of voids obtained were tabulated and statistically analyzed by using ANOVA and t-test. Results: The results showed that the mean contact angle values and number of voids in gypsum casts of Aquasil and 3M Express impression materials increased on disinfection, but decreased on application of topical surfactant, whereas that of Affinis impression material was found to be relatively unchanged on disinfection, but decreased considerably on application of topical surfactant. A change in wettability as well as reduction in number of voids was found to be statistically significant on use of disinfectants and surfactant. Interpretation and conclusion: The wettability of the addition silicone impression materials is affected by disinfection and the application of a wetting agent improves their wettability. There is a positive correlation between the contact angle values and resultant number of voids in gypsum casts.

Key words:  Polyvinyl siloxane, Wettability, Contact angle, Disinfection, Surfactants.

Santhosh Kotian, Narendra.P.Patil, Lekha.K. An In Vitro Study of the Effects of Disinfectants and Wetting Agent on the Wettability of Addition Polymerized Silicone Impression Materials and Void Formation in Dies. International Journal of Prosthetic Dentistry2011:2(2):7-15. © 2011 International Journal of Prosthetic Dentistry. Published by Publishing Division, Celesta Software Private Limited. All Rights Reserved.

Received on: 11/11/2010 Accepted on: 11/12/2010       

Introduction


Polyvinyl siloxane impression materials, also known as vinyl polysiloxane, or, addition reaction silicones, have become one of the most popular impression materials over the past decade. Although they are among the most expensive impression materials, they are now used in a wide variety of situations in fixed prosthodontics, operative dentistry, removable prosthodontics and implant dentistry owing to their excellent physical properties.(1) Their accuracy is unsurpassed and they can record fine details. They have the best elastic recovery of all available impression materials and allows the opportunity to make multiple pours (1)and no volatile by-products are produced, except for release of hydrogen gas in rare occasions due to other reactions.

One of the disadvantages of the addition silicone impression materials is its inherent hydrophobic nature.(2) The hydrophobic properties are related to the materials’ chemical structure, which contains hydrophobic, aliphatic hydrocarbon groups surrounding the siloxane bond. Hence they require an absolute dry field for an acceptable impression. Although these materials have been reported by certain manufacturers to be ‘hydrophilic’ by the addition of certain non ionic surfactants, they are at best slightly less hydrophobic than their predecessors.(1) Their hydrophobic nature has resulted in poor wettability, due to which the gypsum slurry fails to readily wet and flow over the impression surface, resulting in an increased number of voids in gypsum casts.(3) A study done by Pratten and Craig(4) showed that the poor surface wettability of addition silicone impression materials was responsible for the formation of voids during clinical impression making and the production of artificial stone casts and dies.

Possible transmission of pathogenic microorganisms by means of dental impressions and cast and die materials is of great concern to the office and laboratory personnel, which demands for the need of disinfecting the impressions before pouring the casts and dies. Several studies have shown that disinfection procedures can affect the impression material by increasing or decreasing its wettability.(5)

Surfactants applied to an impression have been shown to reduce the number of voids in stone dies poured from the impressions. Although hydrophilic polyvinyl siloxane containing a surfactant agent wet a surface adequately, a study done by Panichuttra et al(6) has shown them to be slightly less dimensionally accurate than hydrophobic polyvinyl siloxanes, and that topical surfactants were far more effective than intrinsic surfactants to maximize accuracy and reduce the risk of air voids in the casts.

The aim of this study was to evaluate the effects of various disinfectants and wetting agent on the wettability of various addition polymerised silicone impression materials and its correlation with void formation in dies.

The objectives of this study was to evaluate the effect of disinfection procedures and the use of a surface wetting agent on the wettability of addition polymerised silicone impression materials, to evaluate the effect of disinfection procedures and the use of a surface wetting agent on the void formation in dies and to study the relationship between the wettability of an elastomeric impression material and void formation in dies.


Materials and Methods

Addition silicone Impression Materials used in the study

Product Name

Manufacturer

Aquasil putty  [AQ]

Dentsply DeTrey, GmbH, 78467, Konstanz, Germany.

Aquasil LV light body [AQ]

Dentsply Caulk, Dentsply International Inc., Milford, DE 19963-0359.

Affinis putty [AF]

Coltene/Whaledent AG, Feldwiesenstrasse 20, 9450, Altstatten/Switzerland.

Affinis light body [AF]

Coltene/Whaledent AG, Feldwiesenstrasse 20, 9450, Altstatten/Switzerland.

Express STD putty [3M]

3M ESPE Dental products, St. Paul, MN 55144-1000.

Express light body [3M]

3M ESPE Dental products, St. Paul, MN 55144-1000.


 


Immersion disinfectants used in the study

Product name

Type

Manufacturer

Cadicide [CC]

2% glutaraldehyde

Casil Health Products LTD, 708, Sarkhej-Dholka road, Ahmedabad India.

Cadidine [CD]

Povidone iodine 0.5%

Jeps Pharmaceuticals, Rampur Ghat, Paonta Sahib, Dist. H.P.), India.

 


Surface wetting agent used in the study

Product name

Manufacturer

Aurofilm [A]

BEGO Bremer Goldschlagerei Wilh. Herbst GmbH & Co., Wilhelm-Herbst-Str.1, D-28359, Bremen.

 

ADA Type IV, high strength, improved dental stone used in the study

Product name

Manufacturer

KALROCK

Kalabhai Karson PVT Ltd, Regd. off. 256, Sardar V Patel road, Mumbai – 400 004, India.

 

Number of samples and test conditions for contact angle measurement

Test conditions

No. of samples

Dry (control)                 [AQ,AF,3M]

10

Cadicide + Aurofilm      [CCA]

10

Cadidine + Aurofilm      [CDA]

10

Aurofilm                        [A]

10

 

Number of samples and test conditions for cast void measurement

Test conditions

No. of samples

Dry(control)                 [AQ,AF,3M]

10

Cadicide                      [CC]

10

Cadidine                      [CD]

10

Aurofilm                       [A]

10

Cadicide + Aurofilm     [CCA]

10

Cadidine + Aurofilm     [CDA]

10

 


Methodology

This study was divided into 2 parts.

(1)    Investigation of the contact angle of the addition silicone impression materials with deionised water.

(2)    Examination of the number of voids in stone casts made from the addition silicone impression materials.

For the first part of the study, putty and light body consistencies of three different hydrophilic addition silicone impression materials namely, Aquasil (Dentsply), Affinis (Coltene/Whaledent) and Express (3M ESPE) were selected.

Each impression material was mixed according to manufacturer’s instructions with an automatic cartridge-mixing device. Specimens of 28 mm in diameter and 2 mm thickness were prepared by compressing the impression material between a custom made stainless steel mould (Fig.1) of the same dimensions and a glass slab.

Specimens were made of Putty light body wash technique considering it to be the most commonly used technique for impression making procedures. Forty specimens were made for each material (Fig. 2).

 

Figure 1             Figure 2

 

The disinfecting solutions used were Cadicide (Casil Health Products LTD) and Cadidine (Jeps Pharmaceuticals) and the surfactant used was Aurofilm (BEGO).

The test conditions were as follows:

1.     Dry (control)

2.     Cadicide + Aurofilm

3.     Cadidine + Aurofilm

4.     Aurofilm

Each test condition contained 10 samples of each impression material.The samples in the first test condition were left untreated and dry, and served as control. The samples in the second and third test conditions were immersed in the respective disinfectant solutions for 30 minutes, as recommended by the United States Centre for Disease Control (CDC). After the immersion period, the samples were rinsed with distilled water and air dried. The samples of the fourth test condition were sprayed with Aurofilm surfactant.

Wettability of the light body surface of each sample was determined by measuring the contact angle between the surface and a drop of deionized water. Contact angle measurement was made with a Rame-Hart goniometer (Rame-Hart Inc.) A single drop of 10 microlitres of deionised water was placed on six different surfaces of each sample, and two readings were taken for each drop, one minute after the drop was placed on the sample. The inverted image of the drop was observed through the eyepiece of the goniometer. The view through the eyepiece showed a horizontal axis which was adjusted to the surface of the sample, a vertical axis which was adjusted to form a tangent to the curved surface of the drop at the point of three-phase contact and a pointer which showed the resultant reading. (Fig.3).  Samples tested for contact angle following disinfection, were sprayed with Aurofilm surfactant and contact angle was again measured, following the same procedure as above.

The values were recorded and tabulated. For each material, the mean and standard deviations within the samples for each group were calculated. Significant differences between the groups for each impression material were determined using statistical analysis (ANOVA and Student’s t – test).

For the second part of the study, a stainless steel die with a circular cross-hatched surface of 28 mm diameter and 2 mm thickness (Fig. 4) was machined. Circular acrylic resin custom impression trays were fabricated corresponding to the die. The trays were coated with tray adhesive (Caulk tray adhesive, Dentsply Caulk). Impressions of the circular cross-hatched surface of the die were made using the same impression materials used in the first part of the study.

All impression materials were mixed according to manufacturer’s instructions with an automatic cartridge-mixing device and impressions of the circular cross-hatched surface of the die were made using putty light body wash impression technique. Before each impression procedure, the die was thoroughly cleaned with distilled water. Sixty impressions were made for each of the three different addition silicone impression materials.

 

Figure 3                 Figure 4

 

The same disinfectant solutions and surfactant used in the first part of the study were used.

The test conditions were as follows:

1.     Dry (control)

2.     Cadicide

3.     Cadidine

4.     Aurofilm

5.     Cadicide + Aurofilm

6.     Cadidine + Aurofilm

Each test condition contained ten impressions of each impression material.

The impression samples in the first test condition were left untreated and dry, and served as control. The impression samples in the second, third, fifth and sixth test conditions were immersed in the respective disinfectant solutions for 30 minutes as recommended by the United States Centre for Disease Control (CDC). After the immersion period, the samples were rinsed with distilled water and air dried. The impression samples of the fourth test condition were sprayed with Aurofilm surfactant. The impressions in the fifth and sixth test conditions were sprayed with Aurofilm surfactant, following disinfection, prior to pouring.

ADA Type IV, high strength, improved dental stone (Kalrock, Kalabhai Karson Pvt Ltd) was mixed according to manufacturer’s instructions with water/powder ratio of 23/100 under vacuum using a vacuum mixer (Multivac – 4, Degussa, Germany) and was poured into the impressions using a model vibrator (Multivac – 4, Degussa, Germany). The method of casting was uniform. The gypsum was poured into the impressions from one end to the other, so that the material flowed into all areas of the impressions. The casts were allowed to set for 40 minutes before removal from the impressions.

 

           Figure 5              Figure 6

 

Ten casts were made for each testing group for each impression material. Casts made for evaluation of number of voids for Affinis Control group is shown in (Fig. 5) Casts were examined using their magnified images (magnification of 130 %) on a computer screen and voids in the cross-hatched surface of the casts were counted and noted (Fig. 6).   For each material, the mean and standard deviations within the samples were calculated. Significant differences between the groups for each impression material were determined using statistical analysis (t test).

Results

Part I: Evaluation of the effect of disinfection procedures and the use of a surface wetting agent on the wettability of addition polymerised silicone impression materials

 

The mean and standard deviation of the contact angle values of deionised water on AQUASIL impression material in the groups AQ, AQCC, AQCD, AQA, AQCCA and AQCDA showed highest contact angle value for the Group AQCD (46.13±0.86), followed by Group AQCDA (40.37±0.69), Group AQCC (37.39±0.69), Group AQ (35.85±3.12), Group AQCCA (28.14±0.52) and the least contact angle value was that of Group AQA (18.09±0.54).

The mean and standard deviation of the contact angle values of deionised water on AFFINIS impression material in the groups AF, AFCC, AFCD, AFA, AFCCA and AFCDA showed highest contact angle value for the Group AF (93.40±0.47), followed by Group AFCD (93.39±1.29), Group AFCC (89.52±0.61), Group AFCCA (85.27±1.01), Group AFCDA (83.74±0.38) and the least contact angle value was that of Group AFA (45.97±0.41).

The mean and standard deviation of the contact angle values of deionised water on 3M EXPRESS impression material in the groups 3M, 3MCC, 3MCD, 3MA, 3MCCA and 3MCDA showed highest contact angle value for the Group 3MCC (96.46±1.26), followed by Group 3MCD (95.23±0.95), Group 3M (94.16±1.02), Group 3MCDA (56.32±0.49), Group 3MCCA (45.89±0.65) and the least contact angle value was that of Group 3MA (36.55±0.56).

The statistical analysis of the mean contact angle values of groups AQ, AQCC, AQCD, AQA, AQCCA and AQCDA of AQUASIL impression material using the ANOVA test showed statistically significant difference between the groups (F = 490.5007, p = 0.0000 at 1% level of significance).

The statistical analysis of mean contact angle values of groups AF, AFCC, AFCD, AFA, AFCCA and AFCDA of AFFINIS impression material using the ANOVA test showed statistically significant difference between the groups (F = 5442.9750, p = 0.0000 at 1% level of significance).

The statistical analysis of mean contact angle values of groups 3M, 3MCC, 3MCD, 3MA, 3MCCA and 3MCDA of 3M EXPRESS impression material using the ANOVA test showed statistically significant difference between the groups (F 10125.2566, p = 0.0000 at 1% level of significance).

            The statistical comparison of mean contact angle values by Student’s t-test among pairs of groups of Aquasil, Affinis and 3M EXPRESS impression materials showed significant difference  among the groups AQ-AF, AQ-3M, AQA-AFA, AQA-3MA, AFA-3MA, AQCC-AFCC, AQCC-3MCC, AFCC-3MCC, AQCCA-AFCCA, AQCCA-3MCCA, AFCCA-3MCCA, AQCD-AFCD, AQCD-3MCD, AFCD-3MCD, AQCDA-AFCDA, AQCDA-3MCDA and AFCDA-3MCDA at 1% level of significance. Highly significant difference was found between the groups AF-3M at 5 % level of significance.

 

Part II: Evaluation of the effect of disinfection procedures and the use of a surface wetting agent on the on the void formation in dies.

 

The mean and standard deviation of the number of voids produced in gypsum casts of AQUASIL impression material in the groups AQ, AQCC, AQCD, AQA, AQCCA and AQCDA showed highest number of voids for the Group AQCD (7.9±6.0), followed by Group AQCC (6.6±2.3), Group AQ (4.9±1.5), Group AQCDA (2.7±4.0), Group AQCCA (2.2±1.2) and the least number of voids was that of Group AQA (0.7±0.8).

The mean and standard deviation of the number of voids produced in gypsum casts of AFFINIS impression material in the groups AF, AFCC, AFCD, AFA, AFCCA and AFCDA showed highest number of voids for the Group AF (17.3±5.8), followed by Group AFCD (16.0±10.6), Group AFCC (7.8±4.5), Group AFCCA (3.7±5.2), Group AFCDA (0.8±1.1) and the least number of voids was that of Group AFA (0.4±0.7).

The mean and standard deviation of the number of voids produced in gypsum casts of 3M EXPRESS impression material in the groups 3M, 3MCC, 3MCD, 3MA, 3MCCA and 3MCDA showed highest number of voids for the Group 3MCC (34.4±8.2), followed by Group 3MCD (15.7±7.0), Group 3M (12.6±5.3), Group 3MCDA (2.2±1.8), Group 3MCCA (1.8±1.3) and the least number of voids was that of Group 3MA (0.7±1.1).

The statistical analysis of the number of voids of groups AQ, AQCC, AQCD, AQA, AQCCA and AQCDA of Aquasil impression material showed statistically significant difference between the groups (F = 7.3858, p = 0.0000 at 1% level of significance).

The statistical analysis of the number of voids of groups AF, AFCC, AFCD, AFA, AFCCA and AFCDA of Affinis impression material showed statistically significant difference between the groups (F = 17.038, p = 0.0000 at 1% level of significance).

The statistical analysis of the number of voids of groups 3M, 3MCC, 3MCD, 3MA, 3MCCA and 3MCDA of 3M Express impression material showed statistically significant difference between the groups (F = 66.9958,  p = 0.0000 at 1% level of significance).

      The statistical comparison of number of voids by student’s t-test among pairs of groups of Aquasil, Affinis and 3M Express impression materials showed that significant difference was found among the groups AQ-AF, AQ-3M, AQCC-3MCC and AFCC-3MCC.Highly significant difference was found between the groups AQCD-3MCD with between 1% and 5 % level of significance. Non-significant differences were found among the groups AF-3M, AQA-AFA, AQA-3MA, AFA-3MA, AQCC-AFCC, AQCCA-AFCCA, AQCCA-3MCCA, AFCCA-3MCCA, AQCD-AFCD, AFCD-3MCD, AQCDA-AFCDA, AQCDA-3MCDA and AFCDA-3MCDA.

Part III: Evaluation of the relationship of the wettability of addition silicone impression materials and void formation in dies.


 

Test condition

Contact Angle (degrees)

No. of Voids

Correlation co-efficient

Remark

Dry (control)

35.85

4.9

 

 

0.82

 

 

S

Cadicide

37.39

6.6

Cadidine

46.13

7.9

Aurofilm

18.09

0.7

Cadicide + Aurofilm

28.14

2.2

Cadidine + Aurofilm

40.37

2.7

Table 1: Correlation analysis of contact angle values of Aquasil impression material with number of voids produced in gypsum casts

S – Significant at 5% level of significance; Critical value of R = 0.8116

 


            Table 1 shows the correlation analysis of contact angle values of Aquasil impression material with number of voids in gypsum casts. A positive correlation was seen (R=0.82), which was found to be statistically significant, at 5 % level of significance.


 

Test condition

Contact Angle (degrees)

No. of Voids

Correlation coefficient

Remark

Dry (control)

93.40

17.3

 

 

0.66

 

 

NS

Cadicide

89.52

7.8

Cadidine

93.39

16.0

Aurofilm

45.97

0.4

Cadicide + Aurofilm

85.27

3.7

Cadidine + Aurofilm

83.74

0.8

Table 2: Correlation analysis of contact angle values of Affinis impression material with number of voids produced in gypsum casts

NS – Non Significant at 5% level of significance; Critical value of R = 0.8116

           


Table 2 shows the correlation analysis of contact angle values of Affinis impression material with number of voids in gypsum casts. A positive correlation was seen (R=0.66), which was found to be statistically non-significant.


 

Test condition

Contact Angle (degrees)

No. of Voids

Correlation co-efficient

Remark

Dry (control)

94.16

12.6

 

 

0.82

 

 

S

Cadicide

96.46

34.4

Cadidine

95.23

15.7

Aurofilm

36.55

0.7

Cadicide + Aurofilm

45.89

1.8

Cadidine + Aurofilm

56.32

2.2

Table 3:Correlation analysis of contact angle values of 3M Express impression material with number of voids produced in gypsum casts

S – Significant at 5% level of significance; Critical value of R = 0.8116

 


            Table 3 shows the correlation analysis of contact angle values of 3M Express impression material with number of voids in gypsum casts. A positive correlation was seen (R=0.82), which was found to be statistically significant, at 5 % level of significance.

 

Discussion

The fabrication of an acceptable fixed or removable prosthesis is dependent upon an accurate void-free cast or die. The interaction of the elastomeric impression material used and gypsum is important in the fabrication of a void-free die, which is determined by the hydrophobic nature of the elastomeric impression material.(3)

Polyvinyl siloxane impression materials have become the most commonly used elastomeric impression materials in fixed prosthodontics, operative dentistry, removable prosthodontics and implant dentistry, owing to a combination of excellent physical properties, handling characteristics and unlimited dimensional stability.1 But these materials have known to be variably hydrophobic, which has resulted in poor wettability and in an increased number of voids in gypsum casts.(3, 4)

Wetting of a surface is the degree of spread of a drop over the solid surface.(7) The wettability of a surface is usually determined by measuring the magnitude of the contact angle formed between a drop of liquid and the surface in question. The contact angle is the angle between the surface of the wetted solid and a line tangent to the curved surface of the drop at the point of three-phase contact.(4) The wettability of impression materials has been shown to be related to the number or volume of air bubbles generated during the pouring of the gypsum casts.(8) When water is the wetting liquid, solids with a contact angle of less than 90 degrees are described as hydrophilic, and solids with a contact angle greater than 90 degrees are described as hydrophobic.(4)

Possible transmission of pathogenic microorganisms by means of dental impressions among dental office and laboratory personnel has called for the need for disinfection of the addition silicone impressions. However, disinfectant solutions can alter the surface properties of polymerized impression material, rendering the material more wettable or less wettable by gypsum.(5)

Topical surfactants sprayed onto impression surfaces have been shown to reduce the number of voids in artificial stone dies poured from the impressions.(3) Some manufacturers have modified the contemporary polyvinyl siloxanes by incorporating certain nonionic surfactants in their formulations and termed them as ‘hydrophilic’. But these are, at best, known to be slightly less hydrophobic than their predecessors.(1)

With due consideration to the above mentioned facts, this study was conducted to evaluate the effects of various disinfectants and wetting agent on the wettability of various addition polymerised silicone impression materials and its correlation with void formation in dies.

For the contact angle measurement, the impression material samples needed to have flat smooth surfaces.(5) 120 specimens of 28mm diameter and 2mm thickness were made by placing the mixed elastomeric impression materials in a custom made stainless steel mould of the same dimensions, and compressing it against a glass slab.

For the examination of the number of voids in stone casts, 180 impressions were made of a circular cross-hatched surface of a stainless steel die 28 mm in diameter and 2 mm in thickness, according to a similar method used by Norling and Reisbick.(9) Casts were poured by a uniform casting method.

Immersion disinfection was used to disinfect the specimens since it was found to be more reliable than spray disinfection because it guarantees that all surfaces of the impression and tray come in contact with the disinfectant solution.(10, 11)

Storer and McCabe(12) concluded from their study on immersion disinfection of impression materials, that silicone rubber impressions could be disinfected in 2% glutaraldehyde solution. The United States Center for Disease Control (CDC) and the American Dental association have considered iodophor solutions acceptable for disinfection of contaminated surfaces. A 30-minute minimum exposure time to these disinfectants has been recommended by the CDC.(13) Also, Merchant et al(13), in his study, found no dimensional changes in vinyl polysiloxane after 30-minute immersion in various disinfectants. Hence, a 30-minute immersion period in Cadicide (2% glutaraldehyde) and Cadidine (0.5 % Povidone-iodine) disinfectant solutions was used in this study.

Although hydrophilic polyvinyl siloxanes containing an intrinsic surfactant agent wet a surface adequately, Panichutra et al7 have shown them to be slightly less dimensionally accurate than hydrophobic polyvinyl siloxanes. They reported that topical surfactants were far more effective than intrinsic surfactants. Therefore, to maximize accuracy, a topical surface wetting agent (Aurofilm) was used in this study.

The contact angle measurements were made using a Rame-Hart goniometer (Rame-Hart Inc.). Casts were examined using their magnified images (magnification of 130 %) on a computer screen and voids in the cross-hatched surface of the casts were counted and noted.

 

Limitations of the study:

1)     The study was done on bare impression surfaces and not with adsorbed salivary films.

2)     Wettability of non polymerised impression materials was not evaluated.

3)     Mode of action of disinfectants and surfactant was not investigated.

4)     Effect of disinfectants and surfactant on other surface characteristics was not investigated.

5)     Only one type of surfactant was used.

6)     Manual variations may change the quality of the impression and the cast.

Conclusion

Within the parameters of this study, following conclusions were drawn.

1)     Aquasil impression material was found to be more hydrophilic, and hence more suitable for clinical use, than Affinis and 3M Express impression materials.

2)     Wettability of Aquasil and 3M Express impression materials was found to be decreased on disinfection and increased on application of topical surfactant.

3)     Wettability of Affinis impression material was found to be relatively unchanged on disinfection, but increased considerably on application of topical surfactant.

4)     Cadicide was found to be a better disinfectant, causing lesser change in wettability, as compared to Cadidine.

5)     The application of Aurofilm topical surfactant was found to increase the wettability for all the three impression materials.

6)     Affinis and 3M Express impression materials, claimed to be ‘hydrophilic’ by their manufacturers, were found to be relatively hydrophobic.

7)     A positive correlation was seen between the contact angle values and resultant number of voids in gypsum casts.

These conclusions are based on the results obtained in accordance with materials and methods used in this study and can be subjected to change with variation in material and methods being employed. 

Authors Affiliation: 1. Dr.  Santhosh Kotian, M.D.S,Consultant Prosthodontist, Jayashree Dental Clinic, Chickmangalore, Karnataka, 2. Dr Narendra P  Patil, M.D.S, Professor & Head of Department, Department of Prosthodontics, Rajasthan Dental College & Hospital, Jaipur, Rajasthan, 3. Dr Lekha K, M.D.S, Professor, Department of Prosthodontics, SDM College of Dental Sciences, Dharwad, Karnataka, India.

Acknowledgement: Department of Prosthodontics, SDM College of Dental Sciences, Dharwad, India.

References

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4.   Pratten D, Craig R. Wettability of a hydrophilic addition silicone impression material. The Journal of Prosthetic Dentistry1989;61(2):197-202.

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7.   Matyas J, Dao N, Caputo A, Lucatorto F. Effects of disinfectants on dimensional accuracy of impression materials. The Journal of Prosthetic Dentistry1990;64(1):25-31.

8.   Robinson PB, Dunne SM, Millar BJ. An in vitro study of a surface wetting agent for addition reaction silicone impressions. The Journal of Prosthetic Dentistry1994;71(4):390-3.

9.   Lorren RA, Salter DJ, Fairhurst CW. The contact angles of die stone on impression materials. The Journal of Prosthetic Dentistry1976;36(2):176.

10.          Chong Y, Soh G, Setchell D, Wickens J. The relationship between contact angles of die stone on elastomeric impression materials and voids in stone casts. Dental Materials1990;6(3):162-6.

11.          Thouati A, Deveaux E, Iost A, Behin P. Dimensional stability of seven elastomeric impression materials immersed in disinfectants. The Journal of Prosthetic Dentistry1996;76(1):8-14.

12.          Storer R, McCabe J. An investigation of methods available for sterilising impressions. British dental journal1981;151(7):217.

13.          Norling BK, Reisbick MH. The effect of nonionic surfactants on bubble entrapment in elastomeric impression materials. The Journal of Prosthetic Dentistry1979;42(3):342-7.

 

 

Address for correspondence

Dr.  Santhosh Kotian,  M.D.S

Consultant Prosthodontist,

Jayashree dental clinic,

Chickmangalore, Karnataka, India

 


 

Source of Support: Nil, Conflict of interest: None Declared

 

 

 

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