|Year : 2021 | Volume
| Issue : 2 | Page : 57-61
An In vitro comparative evaluation of compressive strength, diametral tensile strength, and shear bond strength of type II glass ionomer cement, type IX glass ionomer cement, and Cention N on primary molars
Amit Kumar Pathak1, K Mallikarjuna2
1 Department of Pediatric and Preventive Dentistry, Clove Dental (Star Dental Pvt Ltd.), New Delhi, India
2 Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India
|Date of Submission||02-Feb-2021|
|Date of Acceptance||07-Aug-2021|
|Date of Web Publication||31-Aug-2021|
Dr. Amit Kumar Pathak
Department of Pediatric and Preventive Dentistry, Clove Dental (Star Dental Pvt Ltd.), New Delhi
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: With various restorative materials available and continuous evolution in the field of research for better restorative materials, it is very important to find a material with maximum desirable properties for restoring a primary tooth. Aim: The aim of the study is to compare the compressive strength, diametral tensile strength, and shear bond strength of glass ionomer cement type II (GIC II), GIC IX, and Cention N on primary tooth. Methods: Cylinder of each restorative material, GIC II (GC Corporation, Tokyo, Japan), GIC IX (GC Corporation, Tokyo, Japan), and Cention N (Ivoclar, Vivadent), of dimension 6 mm diameter × 12 mm height (according to ISO 7489:1986) was prepared to check for compressive strength, and disk of dimension 6 mm diameter × 4 mm height (according to ISO 4049 and ANSI/ADA 27) was prepared to check for diametral tensile strength. Furthermore, following the ISO guidelines 29022:2013, restorative materials from various groups were mixed and placed on the flat buccal/lingual enamel of deciduous teeth bonded to the dentin surface of the tooth were used to check for shear bond strength. All the mixing of the materials and samples making were performed by a single investigator. Universal Testing Machine was used to carry out the tests. The data obtained were subjected to ANOVA followed by post hoc Tukey's test. Intergroup comparison was done with Mann–Whitney test. Results: The compressive strength, diametral tensile strength, and shear bond strength of Cention N (Ivoclar) were significantly higher than GIC II and GIC IX (P = 0.00). Between GIC II and GIC IX, there was statistically significant difference (P = 0.00) in terms of diametral tensile strength and shear bond strength, but no significant difference was seen in terms of compressive strength (P = 0.08). Conclusion: Cention N (Ivoclar) presented with high mechanical strength and can be a good alternative to GIC II and GIC IX for restoration of deciduous teeth.
Keywords: Cention N (Ivoclar), compressive strength, diametral tensile strength, glass ionomer cement type II, glass ionomer cement type IX, shear bond strength
|How to cite this article:|
Pathak AK, Mallikarjuna K. An In vitro comparative evaluation of compressive strength, diametral tensile strength, and shear bond strength of type II glass ionomer cement, type IX glass ionomer cement, and Cention N on primary molars. J Interdiscip Dentistry 2021;11:57-61
|How to cite this URL:|
Pathak AK, Mallikarjuna K. An In vitro comparative evaluation of compressive strength, diametral tensile strength, and shear bond strength of type II glass ionomer cement, type IX glass ionomer cement, and Cention N on primary molars. J Interdiscip Dentistry [serial online] 2021 [cited 2021 Dec 5];11:57-61. Available from: https://www.jidonline.com/text.asp?2021/11/2/57/325106
| Clinical Relevance to Interdisciplinary Dentistry|| |
With the continuous evolution in the field of restorative materials, this article is going to help in the clinical scenario of other departments as well.
| Introduction|| |
Oral health is an integral part of general health which is concerned with maintaining the health of craniofacial complex, teeth, and gums, as well as the tissues of the face and head that surrounds the mouth. The human tooth has limited capacity for regeneration.
Dental caries is a chronic disease of the teeth which demineralizes the enamel and dentin as a result of organic acids produced from bacterial fermentation of carbohydrates. It is a multifactorial disease which is mostly determined by diet, plaque, and host factors such as tooth surface, saliva, and pellicle.
In spite of various preventive methods and because of lack of oral awareness, especially in pediatric patients, dental caries presents a challenge to clinicians., Restoring carious teeth is one of the major treatments need of young children. Restoration in the primary dentition is different from a restoration in the permanent dentition, due to limited lifespan of the teeth and also the lower biting forces of children.
Numerous direct filling materials are available for a modern dental practitioner for posterior load-bearing restorations from silver amalgam to modern-day bulk fill composites. Currently, the main concerns regarding the performance of these materials refer to their ability to bear stress, durability, integrity of marginal sealing, and esthetics. Glass ionomer cement (GIC) was introduced by Wilson and Kent, and since then is widely used in pediatric dentistry as is biocompatibility, has anticariogenic ability due to fluoride release and its use in atraumatic restorative technique., In addition, it binds chemically to the enamel and dentin which reduces the need for a retentive cavity preparation, thus making the material useful for minimally invasive and maximal preservation of the tooth structure., However, some disadvantages such as sensitivity to moisture during the initial setting period, short working time, long setting and maturation time, low fracture toughness, and lower wear resistance have limited their use to areas that are subjected to masticatory stress.
GIC IX, with high strength, wear resistance, chemical adhesion to tooth structure, fluoride release, radiopacity, and less technique sensitivity to saliva, was introduced to clinical practice in the late 1990s for geriatric and pediatric patients. However, again, its main disadvantages are moisture sensitivity and low mechanical strength during the early stages of setting.
Esthetically bonded composites have shown better results as restorative materials. However, the disadvantage of resin composite is polymerization shrinkage, resulting in marginal discrepancies causing microleakage which often leads to postoperative sensitivity, marginal discoloration, and secondary caries.,,,, Furthermore, a proper isolation is mandatory for composite restoration, failure to which can lead to failure of the restoration.
Cention N (Ivoclar) is a newly introduced, tooth-colored, basic filling material. It is an “alkasite” UDMA-based restorative material, such as compomer or ormocer, and is essentially a subgroup of the composite resin. It has self-curing powder/liquid with optional additional light-curing property and can therefore be used for bulk placement in retentive preparations with or without the application of an adhesive.,
As Cention N is a newly introduced material, so very less studies are available in the literature comparing all these three parameters of restorative materials. Hence, the aim of this in vitro study is to comparatively evaluate compressive strength, diametral tensile strength, and shear bond strength of conventional GIC II, GIC IX, and Cention N to primary molars.
| Materials and Methods|| |
This is an in vitro study of sample size 10 for each material (GIC II, GIC IX, and Cention N) formed the source of data for compressive strength and diametral tensile strength. Thirty extracted deciduous molars were used to check for shear bond strength by restoring the dentinal surface on the buccal/lingual surface, 10 samples for each material.
Following the principles of the Declaration of Helsinki, and after obtaining written consent from the parents, only deciduous molar teeth with intact crown structure, extracted for orthodontic reasons, kept in saline to prevent dehydration were used in the study. The ethical clearance was taken from Institutional Ethics Committee of College of Dental Sciences, Davangere, for the use of extracted primary teeth (Ref No. CODS/172/2018-19).
Expired materials (GIC II/GIC IX/Cention N), teeth other than deciduous molar teeth, long-standing extracted deciduous molar teeth that have been kept in dry environment and carious teeth were excluded from the study.
Compressive and diametral tensile strength assessment
For the compressive strength testing, 10 restorative cylinders of each restorative materials (GIC II, GIC IX, and Cention N) of dimension 6 mm diameter × 12 mm height (according to ISO 7489:1986) were prepared and stored at 37°C ± 1°C and 95% ±5% humidity for 24 h. For testing, each sample was placed with the flat ends up between the plates of the Instron Universal Testing Machine. A compressive load, at a crosshead speed of 1 mm/min, was applied until the restorative pellet fractured.
For the diametral tensile strength testing, 10 restorative disk-shaped samples of dimension 6 mm diameter × 4 mm height (according to ISO 4049 and ANSI/ADA 27) of each material were prepared and placed on the Instron Universal Testing Machine (Tinius Olsen, United States of America), with the diameter of the pellet coinciding with the direction of the force. The force at crosshead speed of 1 mm/min was applied until the pellets fractured.
Preparation of extracted deciduous molars for the assessment of shear bond strength
The buccal/lingual enamel of 30 deciduous teeth was reduced to a flat surface using a diamond disk and polished thereafter and stored in saline to prevent dehydration of the teeth. The dentin surface was conditioned using polyacrylic acid for 10 s followed by air–water spray for 10 s for GIC group. For the Cention N group, the buccal surface was etched using 37% phosphoric acid for 60 s. Then, the restorative materials from various groups were mixed as per the manufacturer's instructions and placed on the buccal surface of the tooth. Woodpecker LUX V Light Cure Unit with working voltage of 100–220 V and luminous intensity of >1200 mW/cm2 at 5 W with continuous light was used to cure the material. After that, the specimens were stored at 37°C ± 1°C and 95% ± 5% relative humidity for 24 h.
Shear bond strength assessment
The specimens to be tested were placed on the lower assembly of the Instron Universal Testing Machine one by one. A sharp knife-like mandrel was attached to the upper assembly and suspended downward toward the GIC and Cention N blocks. The force was applied at a crosshead speed of 0.5 mm/min with which the restoration block dislodges. This force was recorded and shear bond strength was calculated.
Calculation for compressive, diametral tensile, and shear bond strength
Strength = Force (in kN)/Cross-section (in mm2)
1 kN/mm2 = 1 MPa
The data obtained were subjected to statistical analysis using SPSS version 15.0 software (SPSS Inc., Chicago, USA). The data were statistically analyzed using ANOVA followed by post hoc Tukey's test. Intergroup comparison was done with Mann–Whitney test. A P ≤ 0.05 was considered for data to be statistically significant.
| Results|| |
[Graph 1], [Graph 2], [Graph 3] show the mean compressive strength, diametral tensile strength, and shear bond strength of the three groups. For GIC II, the mean compressive strength was 204.6 ± 8.82 MPa, the mean diametral tensile strength was 9.47 ± 0.17 MPa, and the mean shear bond strength was 4.90 ± 0.23 MPa. For GIC IX, the mean compressive strength was 210.90 ± 32.95 MPa, the mean diametral tensile strength was 11.25 ± 0.38 MPa, and the mean shear bond strength was 7.38 ± 0.15 MPa. For Cention N, the mean compressive strength was 373.54 ± 18.23 MPa, the mean diametral tensile strength was 33.62 ± 0.51 MPa, and the mean shear bond strength was 22.71 ± 0.39 MPa. It was found that Cention N showed the highest value for compressive strength, diametral tensile strength, and shear bond strength in comparison to GIC II and GIC IX .
[Table 1] shows the intergroup comparison of the three groups. The compressive strength, diametral tensile strength, and shear bond strength of Cention N were significantly higher than that of GIC II and GIC IX (P = 0.00). There was no significant difference seen between GIC II and GIC IX (P = 0.08) in terms of compressive strength. Statistically higher significant difference was seen between GIC II and GIC IX (P = 0.00) in terms of diametral tensile strength and shear bond strength.
|Table 1: Intergroup comparison of compressive strength, diametral tensile strength, and shear bond strength of various groups|
Click here to view
| Discussion|| |
GIC binds chemically to tooth by initial crosslinking of Ca++ ions with polyacrylic acid forming calcium polyacrylate chains with final setting involving crosslinking of trivalent aluminum ions with polyacrylic acid forming aluminum polyacrylate chains.
In the present study, compressive strength, diametral tensile strength, and shear bond strength of the restorative materials were tested as these play an important role in withstanding the forces of mastication. Compressive stress results when a body is subjected to two sets of forces in the same straight line toward each other. Tensile stress results when a body is subjected to two sets of forces that are directed away from each other in the same straight line. Shear bond strength is the maximum amount of force required to fracture the interface between a bonded restoration and the tooth surface with the failure occurring in or near the adhesive interface.
In the present study, GIC II and GIC IX were used, as being the most commonly used restorative materials for primary tooth. They adhere to moist tooth structure and base metals, have anticariogenic properties due to release of fluoride. They have thermal compatibility with tooth enamel because of low coefficient of thermal expansion similar to those of tooth structure, are biocompatible, and have low cytotoxicity. Cention N was used as it redefines the basic filling, combining bulk placement, ion release, and durability in a dual-curing, esthetic product-satisfying the demands of both dentists and patients. The basic component of Cention N include barium aluminum silicate which provided strength, ytterbium trifluoride which is responsible for radiopacity, Isofiller (tetric N-Ceram technology) which acts as shrinkage stress relief, calcium barium aluminum fluorosilicate for strength and fluoride release, and calcium fluorosilicate for fluoride, hydroxide, and calcium ions release.
Considering the importance of compressive strength, diametral tensile strength, and shear bond strength of restorative materials, the purpose of this study undertaken was to evaluate and compare the compressive strength, diametral tensile strength, and shear bond strength of GIC II, GIC IX, and Cention N on the primary teeth. To better understand the properties of materials, the study was done on the smooth surface.
The difference between Cention N (Ivoclar) and GIC could be because Cention N (Ivoclar) due to the sole use of crosslinking methacrylate monomers in combination with a stable and efficient selfcure initiator, exhibits a high polymer network density and high degree of polymerization over the complete depth of the restoration.
Compressive strength values for GIC were in agreement with previous studies done by Jaidka et al., Bresciani et al., and Bali et al. Diametral tensile strength values for GIC were in agreement with previous studies done by Jaidka et al. and Bresciani et al. Shear bond strength values for GIC were in agreement with previous studies done by Jaidka et al.,,
20% polyacrylic acid (GC Cavity Conditioner) was applied for 10 s before application of GIC II and GIC IX . It alters the surface energy, exposing highly mineralized tooth surface to diffusion of acid and ion exchange. This enhances adaptation of cement. A previous study found optimal results when using a short (10 s) etch with polyacrylic acid.
The difference in compressive strength, diametral tensile, and shear bond strength in the study could be attributed to the nanoparticle size of inorganic filling in Cention N.
Since this is an in vitro study, mechanical strength may be quite different when compared to the dynamic complex biological system in the oral cavity in vivo. In particular, we did not address the role of saliva, erosive and abrasive challenges, or resin expansion and contraction by thermal cycling. Thus, direct extrapolations to clinical conditions must be exercised with caution by means of in vivo studies.
| Conclusion|| |
Within the limitation of this study, it can be concluded that use of Cention N (Ivoclar) could be superior to GIC II and GIC IX, for restoration of carious lesion on primary teeth.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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