|Year : 2016 | Volume
| Issue : 3 | Page : 280-284
A comparative evaluation of microleakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x: An in vitro study
Rashmeet Walia, Purshottam Jasuja, Kanika Gupta Verma, Suruchi Juneja, Aditi Mathur, Lovejeet Ahuja
Department of Paediatric and Preventive Dentistry, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India
|Date of Web Publication||25-Jul-2016|
25 Beauty Avenue, Phase V, Circular Road, Amritsar, Punjab
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Microleakage around dental restorative material and strength to withstand the masticatory forces is major problem in dentistry. Instead, many new materials available, very few actually bond to tooth surface and bear masticatory load. Aim: The aim of this study is to evaluate and compare the microleakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x. Materials and Methods: For the evaluation of microleakage, Class V cavities were prepared on sixty human premolar teeth and divided into four study groups (n = 15): Group I (Ketac Molar), Group II (Giomer), Group III (Zirconomer), and Group IV (Ceram-x). The samples were thermocycled and subjected to dye penetration test. The sections were made and evaluated under stereomicroscope at × 40 magnification. For the compressive strength evaluation, sixty cylindrical specimens were fabricated measuring 5 mm × 6 mm and grouped into four study groups (n = 15): Group I (Ketac Molar), Group II (Giomer), Group III (Zirconomer), and Group IV (Ceram-x). All were then subjected to the Universal Testing Machine at crosshead speed of 1 mm/s. Statistical Analysis Used: The data were analyzed using paired t-test and ANOVA. Results: The microleakage was found insignificant (P > 0.05) for all study groups, with Giomer showing maximum followed by Zirconomer, Ceram-x, and Ketac Molar. The compressive strength was found to be highly significant (P < 0.01) with the maximum score for Giomer followed by Ceram-x, Zirconomer, and Ketac Molar. Conclusion: The sealing ability was maximum in Ketac Molar, Zirconomer, Ceram-x, and Giomer whereas the compressive strength was maximum for Giomer followed by Ceram-x, Zirconomer, and Ketac Molar.
Keywords: Ceram-x, compressive strength, Giomer, Ketac Molar, microleakage, Zirconomer
|How to cite this article:|
Walia R, Jasuja P, Verma KG, Juneja S, Mathur A, Ahuja L. A comparative evaluation of microleakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x: An in vitro study. J Indian Soc Pedod Prev Dent 2016;34:280-4
|How to cite this URL:|
Walia R, Jasuja P, Verma KG, Juneja S, Mathur A, Ahuja L. A comparative evaluation of microleakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x: An in vitro study. J Indian Soc Pedod Prev Dent [serial online] 2016 [cited 2021 Mar 9];34:280-4. Available from: https://www.jisppd.com/text.asp?2016/34/3/280/186746
| Introduction|| |
The basic purpose of the restorative materials is to substitute the biological, functional, and esthetic properties of healthy tooth structure. One of the most important requirements for the success of restoration is to prevent the microleakage, which is achieved with the proper adherence of restorative material to the cavity walls. The inadequacy of the restorative materials to attain the complete marginal seal leads to occurrence of microfissures, in which the seepage of ions, fluids, and bacteria occurs, which causes secondary decay, sensitivity, and pulpal infections. Thus, the continuing quest for better restorative material, the newer materials were introduced with better biomechanical properties such as better marginal seal, good esthetics, easy polishability, biocompatibility, and compressive strength in evolution.
The compressive strength of a material is defined as the amount of stress required to distort the material in an arbitrary amount. It is calculated by dividing the maximum load by the original cross-sectional area of a specimen. The necessity of good compressive strength, with minimum microleakage, has led to the development of various posterior esthetic restorative materials with promising results such as glass ionomer cements, composites, compomers, Giomers, and Zirconomer.
Since glass ionomer cements fail to achieve sufficient hardness, resistance to fracture and have a low abrasion resistance, a newer conventional glass ionomer cement, Ketac Molar, was evolved with improved mechanical properties.
A new hybrid esthetic restorative material, Giomer, was introduced with physical properties and biocompatibility of composite resin and added benefits of high radiopacity, fluoride release, and antiplaque effect of glass ionomer cement. Beautifil II, a type of Giomer, is based on prereacted filler technology, where prereacted glass particles are incorporated in the resin matrix to enhance its strength.
A new class of restorative glass ionomer that comprises the strength and durability of amalgam is evolved as a recent posterior restorative material called Zirconomer. The inclusion of Zirconia fillers in glass component of Zirconomer reinforces the structural integrity of restoration and imparts superior mechanical properties in posterior load-bearing areas.
The new era is the era of nanotechnology, which is being used extensively to produce restorative materials with improved esthetics, adhesion, and mechanical properties. One of the recent advancements is the Ceram-x, the nanocomposite which is radiopaque, light curable restorative material being used for restoration of both permanent and primary teeth.
Thus, the present in vitro study was undertaken to compare the marginal leakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x in Class V restorations of premolars to evaluate the best restorative material for posterior teeth.
| Materials and Methods|| |
For the evaluation of microleakage, sixty caries-free freshly extracted maxillary and mandibular premolars were collected and used. All the study samples were cleaned and kept in solution with thymol crystals until further use.
Standardized Class V cavities of 2 × 2 × 3 dimensions were prepared with a straight fissure bur (ISO size no. 109/013) and inverted cone bur (ISO size no. 010/013) on the buccal surfaces of each tooth. Sixty study samples were randomly divided into four equal groups, Group I–IV, consisting of 15 samples of each group, Group I (Ketac Molar), Group II (Giomer), Group III (Zirconomer), and Group IV (Ceram-x) and were filled according to the manufacturer's instructions.
All the samples were stored in distilled water, and then subjected to finishing and polishing. The samples were then subjected to thermocycling for 1500 cycles between the temperature range of 12° C ± 2 and 60° C ± 2 with an interval of 30 s in each bath.
After the retrieval of samples from the thermocycling machine, two coats of nail varnish were applied on all the tooth surfaces, except 1 mm around the restoration and root apices were sealed with yellow sticky wax. The teeth were then soaked in 2% methylene blue dye in a water bath for 24 h, cleaned under tap water, and nail varnish was removed with scalpel.
The samples were sectioned from the midpoint mesiodistally into two halves in buccolingual direction along their long axis and examined under stereomicroscope at ×40 magnification. The degree of marginal leakage was determined by scoring criteria given by Prabhakar et al.
- 0 = No dye penetration
- 1 = Dye penetration between the restoration and tooth into enamel only
- 2 = Dye penetration between the restoration and tooth into enamel and dentin
- 3 = Dye penetration between the restoration and tooth into the pulp chamber.
For the evaluation of compressive strength, sixty cylindrical specimens were prepared in customized split cylindrical molds, measuring 5 mm × 6 mm. A total number of sixty samples were prepared according to four experimental groups (n = 15): Group I (Ketac Molar), Group II (Giomer), Group III (Zirconomer), and Group IV (Ceram-x). After curing and setting of all materials, they were removed from the split cylindrical mold and stored in distilled water for 24 h.
All specimens were then transferred to the Universal Testing Machine individually and subjected to load cell of 20 kN, at a crosshead speed of 1 mm/s at an angle of 90° to restoration until visible or audible evidence of failure was observed. For all the study samples, the compressive strength was calculated in megapascals using the formula:
CS = Load/πr2
where CS = compressive strength; load is expressed in Newton (N); π = 3.14; r = half the diameter of mold.
| Results|| |
The data for microleakage and compressive strength analysis were obtained and then subjected to statistical analysis using SPSS software (version 20, SPSS Inc., Chicago, IL, USA).
For the microleakage, the intraclass correlation statistical analysis was done to check the interobserver reliability for the triplicate study of all the four study groups and the results were found to be insignificant (P > 0.05). The statistical correlation was done with the mean value scores of all the four study groups using analysis of variance and it was found to be statistically significant (P < 0.05) [Table 1]. The intergroup comparison of all the four groups was done using paired t-test that showed a highly significant difference between Groups I and II (P < 0.01) whereas insignificant difference was found between Groups I and III, I and IV, and III and IV (P > 0.05). The statistically significant difference was found in microleakage scores between Groups II and IV (P < 0.05) [Table 2].
|Table 1: Mean values and statistical analysis of variance for microleakage according to dye penetration test of four study groups|
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|Table 2: Paired t-test, statistical analysis used for intergroup comparison of all the four groups with each other|
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For the results of compressive strength, the mean value scores of all the four study groups were obtained and statistically analyzed using analysis of variance and highly significant correlation was observed (P < 0.01) [Table 3]. The intergroup comparison was done using paired t-test, for all the four study groups, and the results showed a highly significant correlation between the Groups I and II, I and III, I and IV, III and IV, and II and III (P < 0.01), whereas an insignificant difference was found between Groups II and IV (P > 0.05) [Table 4].
|Table 3: Mean values and statistical analysis of variance for compressive strength of all the four study groups|
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|Table 4: Paired t-test, statistical analysis used for intergroup comparison of all the four groups with each other|
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Thus, the results obtained from the study showed that the maximum microleakage was present in Giomer followed by Zirconomer, Ceram-x and the least was in Ketac Molar [Figure 1] whereas the maximum mean value score of compressive strength was found for the Giomer followed by Ceram-x, Zirconomer and the least for the Ketac Molar.
|Figure 1: Dye penetration of study samples: (a) Giomer, (b) Zirconomer, (c) Ceram-x, and (d) Ketac Molar|
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| Discussion|| |
There is a continual scrutiny for the restorative materials that ensure adhesion to the tooth structure to curtail the leakage potential and the materials which can withstand the masticatory forces. The microleakage and compressive strength test are used as a measure by which clinicians and researchers can predict the performance of a restorative material. The need for restorative material, with better bond characteristics and strength to withstand the stress of masticatory forces, leads to the recent advances in the restorative dentistry.
For evaluating the microleakage, the study samples were stored in distilled water with few thymol crystals, to maintain aseptic conditions before cavity preparation. After retrieving from distilled water, Class V cavities were prepared in each tooth. In the present study, Class V cavities were selected because of its configuration or “C” factor. The “C” factor of Class V restoration is 5 which corresponds to the ratio between the number of bonded to unbonded surfaces which is responsible for the internal bond disruption as well as marginal gaps around the restorations.
The study samples were divided into four equal groups and were filled according to the manufacturer's instructions. The fifth-generation bonding agent was used in this study. It is an acetone-based adhesive system, with hydrophilic components, which can dislodge moisture from the conditioned dentin and attain an intimate interaction at the demineralized intertubular and peritubular dentin, creating the hybrid layer, which is essential for an ideal bond to dentin. The studies conducted by Kallenos et al. and Gupta et al. showed that fifth-generation bonding agents exhibited less microleakage as compared to sixth- and seventh-generation adhesive systems; hence, fifth-generation adhesive was preferred to evaluate the microleakage of restorative materials in our study.
After completing the restorations, all the study samples were subjected to thermocycling. The process of thermocycling was done to mimic the intraoral temperature variations. The yellow sticky wax has been used to occlude the apices of the roots. Two coats of nail varnish were applied, leaving 1 mm wide margin around the restoration to avoid any dye penetration from invisible cracks, areas devoid of enamel or cementum, etc. Then, samples were immersed in 2% methylene blue dye for 24 h. The methylene blue dye was chosen because of its low molecular weight, which can easily facilitate its diffusion because of its small particle size as suggested by Pasricha.
The study concluded that microleakage score was found maximum in Group II (Giomer) followed by Group III (Zirconomer) and Group IV (Ceram-x) and the least was in Group I (Ketac Molar).
The mean microleakage for Group I (Ketac Molar) was least that proves that it is more effective in preventing microleakage. The study was in accordance with a study conducted by Fracasso et al. The probable reason for decreased microleakage in this group is due to the formation of strong chelation reaction with calcium on the tooth surface. There are chemical interactions of polyalkenoic acids and hydroxyapatite which produce adequate marginal sealing as studied by Eronat et al.
Ceram-x showed less microleakage as compared to Giomer and Zirconomer but more than Ketac Molar, which was in accordance with the studies conducted by Al-Dahan et al. and Hegde et al. The probable reason for lesser microleakage may be due to its structure which comprises biocompatible polysiloxane net with low shrinkage even before light curing, and due to its high molecular weight, they undergo less shrinkage than composites as studied by Yadav et al.
The microleakage score of Group III (Zirconomer) indicated that it has lesser microleakage score than Giomer, but more than Ceram-x and Ketac Molar, which was in accordance with the results obtained by Patel et al. As Zirconomer is a new material and not much of studies have been done on it, more research work is needed to be done to have a better vision about this new material.
The microleakage score of Group II (Giomer) showed maximum microleakage, which was in accordance with the Deliperi et al. and Yadav et al. The reason for maximum microleakage is the high filler content, without bonding of the resin with S-PRG filler, as studied by Karim et al.
The maximum mean value score of compressive strength was found for the Group II (Giomer) followed by Group IV (Ceram-x) and III (Zirconomer) and the least mean value score was found for the Group I (Ketac Molar).
Giomer had the highest value for compressive strength which was in accordance with the study conducted by Quader et al. which showed the resin-based PRG fillers and cross-linked polymer matrices that result in the higher compressive strength than the acid-base reaction in glass ionomers.
Ceram-x showed less value of compressive strength than Giomer but more than Zirconomer and Ketac Molar, which was in accordance with the results of the study conducted by Hegde et al. The mechanical properties depend on the particle size of the inorganic filler, which is 10 nm for Ceram-x. Thus, the lesser dimension of the particles and an increased filler load can be attained in Ceram-x, which without increasing their viscosity, increases the mechanical properties such as compressive strength.
Zirconomer showed lesser value of compressive strength as compared to Giomer and Ceram-x but more than Ketac Molar. The addition of zirconia as filler particle in the glass component of Zirconomer improves the mechanical properties of the restoration by reinforcing structural integrity of the restoration in load-bearing areas.
Ketac Molar had the lowest value for compressive strength as compared to the other study groups. The reason for the low score of compressive strength for Ketac Molar is due to the poor mechanical properties, such as low fracture strength, toughness, and higher occlusal wear rate as studied by Lohbauer.
The present study was an in vitro study and the results obtained from this may not be correlated with the clinical situations, thus to provide relevant information regarding these restorative materials, the study should be conducted with large sample size and in vivo conditions, to correlate the present results.
| Conclusion|| |
The following conclusions were drawn from the present study.
- The maximum microleakage was obtained in Group II (Giomer) followed by Group III (Zirconomer) and Group IV (Ceram-x) and the least was in Group I (Ketac Molar)
- The maximum mean value score of compressive strength was found for Group II (Giomer) followed by Group IV (Ceram-x) and Group III (Zirconomer) and the least for the Group I (Ketac Molar).
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]