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Table of Contents
ORIGINAL ARTICLE
Year : 2019  |  Volume : 6  |  Issue : 1  |  Page : 1-3

Evaluation and comparison of the effect of different chemical surface treatments (monomethyl methacrylate monomer, dichloromethane, and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer solvent) on the shear bond strength of acrylic resin teeth to the heat cure denture base resin


1 Department of Prosthodontics, GDC &H, Mumbai, Maharashtra, India
2 Department of Prosthodontics, GDC &H, Aurangabad, Maharashtra, India

Date of Web Publication26-Jul-2019

Correspondence Address:
Dr. Rupali Pathak
1104, Imperia, Mahavir Millenium, Vasant Vihar, Pokharan Road No. 2, Thane West, Thane - 400 607, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/INPC.INPC_17_19

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  Abstract 


Background: Prefabricated acrylic resin teeth for dentures were started in use from 1940. About 26%–33% of denture repairs are the result of debonded teeth which cause distress and increased cost for patients. Taking into consideration the importance of properly bonded teeth to denture bases, this in-vitro study was designed to evaluate and compare the effects of three different chemicals on shear bond strength of cross-linked acrylic resin teeth with heat cure denture base resin.
Methodology: This study was carried out in Government Dental College and Hospital, Mumbai, in collaboration with the Indian Institute of Technology, Powai. For the purpose of the study, 100 maxillary right central incisors, made up of heat cure cross-linked acrylic resin (MAARC) were collected. The wax samples were randomly divided according to systematic random sampling and coded into four groups of 25 samples each. The four groups were the control group, the monomethyl methacrylate group, the dichlormethane group and trichloroethane+ monomethyl methacrylate group.
Results: The control group had lowest value for shear bond strength ranging from 117 N to 181 N with a mean of 147.8 N, whereas 1:1 mixture of v/v of 30% trichloromethane and monomethyl methacrylate had the highest value ranged from 145 N to 310 N with the mean value of 224.88 N. Among the chemical solvents used, monomethyl methacrylate had the lowest shear bond strength ranging from 120 N to 256 N with the mean value 187.32 N.
Conclusion: The study concluded that chemical surface treatment of cross-linked acrylic teeth with 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer gave the highest strength.

Keywords: Acrylic resin teeth, chemical surface treatments, heat cure denture base resin, prefabricated, shear bond strength


How to cite this article:
Pathak R, Kumar R, Mahajan S, Singh P, Tiwari D, Deval P. Evaluation and comparison of the effect of different chemical surface treatments (monomethyl methacrylate monomer, dichloromethane, and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer solvent) on the shear bond strength of acrylic resin teeth to the heat cure denture base resin. Int J Prev Clin Dent Res 2019;6:1-3

How to cite this URL:
Pathak R, Kumar R, Mahajan S, Singh P, Tiwari D, Deval P. Evaluation and comparison of the effect of different chemical surface treatments (monomethyl methacrylate monomer, dichloromethane, and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer solvent) on the shear bond strength of acrylic resin teeth to the heat cure denture base resin. Int J Prev Clin Dent Res [serial online] 2019 [cited 2019 Nov 17];6:1-3. Available from: http://www.ijpcdr.org/text.asp?2019/6/1/1/263456




  Introduction Top


Dental materials have been evolving with time. Similarly, materials used for fabrication of complete dentures have evolved a lot with time. Heat-polymerized polymethyl methacrylate resin is commonly used as a denture base material because of its excellent esthetics, low water sorption and solubility, relative lack of toxicity, repairability, and simple processing technique.[1] Prefabricated acrylic resin teeth for dentures were introduced in 1940. Since then, this material has become the most popular artificial material for denture teeth. Apart from economical advantage, it also bonds chemically to the denture base,[2] but still debonding of denture teeth from denture bases is a major problem in the prosthodontic practice.[3] Previous surveys reported that 26%–33% of denture repairs are the result of debonded teeth which cause distress and increased cost for patients.[4],[5],[6] This detachment may be attributed to the direction of stresses encountered during the function. The most probable reason for failure is the crack propagation from areas of high-stress concentration.[7] Several studies have been carried out to evaluate and study the compatibility of acrylic teeth to denture base resins. The surface modification on the ridge-lap surface of acrylic resin teeth by the application of various chemicals before packing has shown variable results on the bond.[8],[9] Recently, the application of nonpolymerizing solvents such as dichloromethane, trichloromethane, and adhesive bonding agent seems to enhance the bond strength between denture base resin and acrylic resin teeth.[10],[11],[12],[13],[14],[15] Taking into consideration the importance of properly bonded teeth to denture bases, this in-vitro study was designed to evaluate and compare the effects of three different chemicals on shear bond strength of cross-linked acrylic resin teeth with heat cure denture base resin and to visually examine the fractured area to determine the type of failure.


  Methodology Top


This study was carried out in Government Dental College and Hospital, Mumbai, in collaboration with the Indian Institute of Technology, Powai. Attempts were made to standardize the procedure throughout the study to minimize the effects of variable factors on the observations and final result. The Institutional Ethics Committee of Government Dental College and Hospital, Mumbai approved this study. For the purpose of the study, 100 maxillary right central incisors, made up of heat cure cross-linked acrylic resin (MAARC) were collected. The wax samples were randomly divided according to systematic random sampling and coded into four groups of 25 samples each. The four groups were:

  • Group “A” - The “Control” group. (n = 25) Ridge lap of each of the tooth was left untreated.
  • Group “B” - The “Monomethyl methacrylate” group. (n = 25) Ridge lap was painted with heat cure monomethyl methacrylate monomer using microbrush applicator once and left for 3 min before packing [10]
  • Group “C” - The “Dichloromethane” group. (n = 25) Ridge lap was painted with dichloromethane solvent once using microbrush applicator and left for 30 s before packing 25
  • Group “D” - The “1:1 v/v 30% Trichloromethane and heat cure monomethyl methacrylate monomer solvent 39 group (n = 25). Ridge lap was painted with 1:1 v/v 30% trichloromethane and heat cure monomethyl methacrylate monomer solvent” once using microbrush applicator and left for 1 min before packing.52 The sheared specimens were also examined visually to determine the type of fracture at the fracture site. Statistical tests used were: one-way ANOVA (Kruskal–Wallis test), nonparametric tests; Mann–Whitney test and Wilcoxon Signed-Ranks test, and data were analyzed using a significance level of 0.05 to determine the mean differences.



  Results Top


[Table 1] depicts the descriptive statistics of shear bond strength, which includes mean and standard deviation. The control group had lowest value for shear bond strength ranging from 117 N to 181 N with a mean of 147.8 N, whereas 1:1 mixture of v/v of 30% trichloromethane and monomethyl methacrylate had highest value ranged from 145 N to 310 N with the mean value of 224.88 N. Among the chemical solvents used, monomethyl methacrylate had the lowest shear bond strength ranging from 120 N to 256 N with the mean value of 187.32 N.
Table 1: Statistical analysis of shear bond strength of all groups

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[Table 2] reveals that the control group (Group A) showed predominantly adhesive type of failure, whereas the experimental groups (Group B, Group C, and Group D) showed predominantly cohesive type of failure.
Table 2: Comparison of the type of failure of all the groups

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  Discussion Top


All the samples were tested for bond strength between acrylic tooth and acrylic denture base resin. Mann–Whitney U-test revealed that samples in Group B, showed enhanced mean shear bond strength (187 N) when compared to Group A (mean shear bond strength 148 N). This was in accordance with Papazoglou and Vasilas [10] Adeyemi et al.[14] also concluded that priming the denture tooth surface with monomer liquid yielded significantly higher bond strength than other treatments. Papazoglou and Vasilas [10] studied further the reason for this increased strength and came up with the explanation that the application of monomer leads to swelling of the polymer and hence more penetration of monomer into the resin teeth, resulting in strengthening of joint between denture teeth and the denture base resin.[10] There was a significant improvement found in the mean bond strength of samples treated with dichloromethane in Group C (with mean shear bond strength 201 N) over control Group A (with mean shear bond strength 148 N) and over monomethyl methacrylate-treated samples in Group B (mean shear bond strength 148 N). There was a significant improvement found in the mean bond strength of samples treated with 1:1 v/v of 30% trichloromethane and heat cure monomethyl methacrylate solvent in Group D (with mean shear bond strength 225 N) over control Group A (mean shear bond strength 148 N) and over monomethyl methacrylate treated samples in Group B (mean shear bond strength 148 N). However, when it was compared with dichloromethane solvent in Group C (with mean shear bond strength 201 N), the results were not significant, even though the mean shear bond strength was higher. In the present study, for all specimens, interface where failure occurred were inspected. This study revealed that only 11% of cohesive failures occurred in control group, whereas in experimental groups, 93% cohesive failures were revealed. In Group B, C and D, it was distinctly noted that the fracture line always crossed some portion of the teeth as well as denture base, suggesting that application of an external solvent may lead to a better penetration of the free monomer, resulting in a better bond strength. The other finding observed under visual examination was that all the fractures at the interface of the sheared specimens of Group A appeared to be cohesive in nature. This was in accordance with Fletcher-Stark et al.,[15] when a bonding agent was used with light-and heat-polymerized denture base resins, mixed and cohesive failures were observed. Results of this study showed relevance in conjunction to the previous studies and literature.


  Conclusion Top


The study concluded that chemical surface treatment of cross-linked acrylic teeth with 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer gave the highest strength. Chemical surface treatment of cross-linked acrylic teeth with monomethyl methacrylate monomer gave better bond strength than control group, but less than dichloromethane and 1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer. Chemical surface treatment of cross-linked acrylic teeth with dichloromethane gave better bond strength than monomethyl methacrylate monomer, but <1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer. The control group which was left untreated gave the least bond strength. The order of shear bond strength of samples is: control < monomethyl methacrylate monomer < dichloromethane <1:1 v/v 30% trichloromethane and monomethyl methacrylate monomer.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Memon MS, Yunus N, Razak AA. Some mechanical properties of a highly cross-linked, microwave-polymerized, injection-molded denture base polymer. Int J Prosthodont 2001;14:214-8.  Back to cited text no. 1
    
2.
Thean HP, Chew CL, Goh KI. Shear bond strength of denture teeth to base: A comparative study. Quintessence Int 1996;27:425-8.  Back to cited text no. 2
    
3.
Bahrani F, Khaledi AA. Effect of surface treatments on shear bond strength of denture teeth to denture base resins. Dent Res J (Isfahan) 2014;11:114-8.  Back to cited text no. 3
    
4.
Vallittu PK, Lassila VP, Lappalainen R. Evaluation of damage to removable dentures in two cities in Finland. Acta Odontol Scand 1993;51:363-9.  Back to cited text no. 4
    
5.
Darbar UR, Huggett R, Harrison A. Denture fracture – A survey. Br Dent J 1994;176:342-5.  Back to cited text no. 5
    
6.
Saavedra G, Valandro LF, Leite FP, Amaral R, Ozcan M, Bottino MA, et al. Bond strength of acrylic teeth to denture base resin after various surface conditioning methods before and after thermocycling. Int J Prosthodont 2007;20:199-201.  Back to cited text no. 6
    
7.
Prombonas A, Vlissidis D. Effects of the position of artificial teeth and load levels on stress in the complete maxillary denture. J Prosthet Dent 2002;88:415-22.  Back to cited text no. 7
    
8.
Krishna VP, Premalatha A, Babu PJ, Raju DS, Kumar MP, Rao DB. Effect of various chemicals on the bond strength of acrylic tooth and denture base-an in vitro comparative study. J Int Oral Health 2014;6:100-5.  Back to cited text no. 8
    
9.
Cunningham JL. Bond strength of denture teeth to acrylic bases. J Dent 1993;21:274-80.  Back to cited text no. 9
    
10.
Papazoglou E, Vasilas AI. Shear bond strengths for composite and autopolymerized acrylic resins bonded to acrylic resin denture teeth. J Prosthet Dent 1999;82:573-8.  Back to cited text no. 10
    
11.
Spratley MH. An investigation of the adhesion of acrylic resin teeth to dentures. J Prosthet Dent 1987;58:389-92.  Back to cited text no. 11
    
12.
Anusavice KJ, Shen C, Rawls HR. Prosthetic polymers and resins. In: Phillips' Science of Dental Materials. 12th ed., Ch. 19. Missouri: Saunders an Imprint of Elsevier Inc.; 2013. p. 474-98.  Back to cited text no. 12
    
13.
Hargreaves AS. The prevalence of fractured dentures. A survey. Br Dent J 1969;126:451-5.  Back to cited text no. 13
    
14.
Adeyemi AA, Lyons MF, Cameron DA. The acrylic tooth-denture base bond: Effect of mechanical preparation and surface treatment. Eur J Prosthodont Restor Dent 2007;15:108-14.  Back to cited text no. 14
    
15.
Fletcher-Stark ML, Chung KH, Rubenstein JE, Raigrodski AJ, Mancl LA. Shear bond strength of denture teeth to heat-and light-polymerized denture base resin. J Prosthodont 2011;20:52-9.  Back to cited text no. 15
    



 
 
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