International Journal of Oral Health Sciences

ORIGINAL ARTICLE
Year
: 2015  |  Volume : 5  |  Issue : 2  |  Page : 74--79

Assessment of the clinical performance of zirconia infused glass ionomer cement: An in vivo study


AR Prabhakar, Priyanka L Kalimireddy, Chandrashekar Yavagal, S Sugandhan 
 Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere, Karnataka, India

Correspondence Address:
Dr. Priyanka L Kalimireddy
Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere - 577 004, Karnataka
India

Abstract

Aim: To assess the clinical performance of zirconia (ZrO2) infused glass ionomer cement (GIC) compared to conventional GIC. Study Design: Experimental, in vivo, intergroup split-mouth study. Methods: Cavities were prepared on bilateral teeth and restored with Conventional GIC on one side and ZrO2infused glass ionomer on the other. The two sides were compared with regards to their clinical performance and color stability. Results: Statistically significant differences were found with respect to surface texture and color match between ZrO2infused GIC and conventional GIC. Statistics: Results were analyzed using Friedman test and Wilcoxon test. Conclusions: ZrO2infused GIC showed better color stability but conventional GIC was much better as far as color match, surface texture, and marginal adaptation were concerned.



How to cite this article:
Prabhakar A R, Kalimireddy PL, Yavagal C, Sugandhan S. Assessment of the clinical performance of zirconia infused glass ionomer cement: An in vivo study.Int J Oral Health Sci 2015;5:74-79


How to cite this URL:
Prabhakar A R, Kalimireddy PL, Yavagal C, Sugandhan S. Assessment of the clinical performance of zirconia infused glass ionomer cement: An in vivo study. Int J Oral Health Sci [serial online] 2015 [cited 2021 Jan 23 ];5:74-79
Available from: https://www.ijohsjournal.org/text.asp?2015/5/2/74/178501


Full Text

 Introduction



Restorative dentistry is a blend of science and art. The triumph of restorative dentistry is based on the functional and esthetic results of a given intervention. The foundation for aesthetics in the sequence is laid by position, contour, texture, and color.[1] Glass ionomer cement (GIC) was the one of the first aesthetic restorative materials introduced in the dental arena by Wilson and Kent way back in 1972.[2]

The added advantages of active fluoride release and chemical adhesion further justified the extensive usage of GIC in young children. Therefore, they were intensively investigated as restorative materials of choice for deciduous teeth. However, most of these trials have been conducted on the quintessential glass ionomer and not so much on its modifications per se.[3]

The bygone decade has seen several innovative additions to enhance the properties of GIC whilst simplifying its usage. Unlike the early glass ionomers, these newer systems are easy and more practical to use as a dental restorative and luting material for preschoolers, children and teenagers alike.[4] These newer glass ionomers also claim to address the poor physical properties such as surface crazing and low fracture resistance which had negatively affected its' clinical usage for long.[5],[6]

Zirconia (ZrO2) infused GIC (ZIRCONOMER) is one such recent addition to the GIC family which has been introduced to address all the issues that have plagued the conventional ionomer thus far. However, this newer cement Zirconomer has not been challenged clinically and there is only laboratory-based evidence of it having better mechanical properties and superior esthetics.[7]

It has also been claimed to have a shear bond strength equivalent to amalgam and a fluoride releasing capacity similar to conventional GIC. Hence, we ventured with an objective to compare the clinical performance and color stability of ZrO2 infused GIC with conventional GIC so as to put these claims to test.

 Methods



Ethical clearance for this study was obtained from the Institutional review board of Bapuji Dental College and Hospital, Davangere.

This was an experimental, in vivo, inter group split-mouth study. 20 healthy children of age group 5–10 years with at least 2 occlusally cavitated dentinal lesions on the same bilateral primary molar, were selected from the outpatient clinics of Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere. Children with deep dentinal lesions involving the pulp, periapical abscess, pain or swelling were excluded, so were children with developmental disorders and systemic illnesses.

Thus, the study had two groups: Group I, being the control comprised conventional GIC and Group II being the interventional group comprised ZrO2 infused GIC [Table 1].{Table 1}

An informed consent was taken from the accompanying parent/guardian for conducting the procedure. Cavity preparation was then done and restored with conventional GIC on the right tooth and ZrO2 infused GIC on the left tooth [Figure 1],[Figure 2],[Figure 3]. These teeth were then subjected to clinical stability and clinical performance analysis.{Figure 1}{Figure 2}{Figure 3}

Evaluation of color stability

Color stability was assessed by obtaining photographs of each restoration using Nikon D5100 camera and an intra-oral mirror at baseline, 1 month recall and 3 months recall. Images were then transferred to the computer and opened to its natural size with Corel PaintShop Pro X5 [Figure 4]. The identity of the colors (initially and after 1 month and 3 months recall) was retrieved by PaintShop's HSL color system and compared [Figure 5]. These indicators determine a single color.[8]{Figure 4}{Figure 5}

Evaluation of clinical performance

Clinical performance was evaluated by two calibrated examiners trained in the technique but not involved in the treatment procedure. Each restoration was evaluated by using Ryge's/United State Public Health Service criteria at baseline, after 1 month and 3 months recall [Table 2]. If any differences were found between both the examiners a third examiner was called on to make the final decision.[9],[10]{Table 2}

 Results



Results were subjected to Friedman and Wilcoxon tests. ZrO2 infused GIC was found to have better color stability when compared to conventional GIC [Figure 6]a,[Figure 6]b,[Figure 6]c. However, in all the 20 patients the shade of ZrO2 infused GIC did not match with the shade of the tooth [Figure 7]a and [Figure 7]b. 16 out of 20 patients showed poor surface texture with respect to ZrO2 infused GIC [Figure 8]a and [Figure 8]b. No statistically significant differences were found with respect to cavosurface margin discoloration, marginal adaptation, secondary caries, and anatomic form in both the restorations.{Figure 6}{Figure 7}{Figure 8}

 Discussion



In the last 15 years, manufacturers always worked diligently to produce GIC systems that overcome the 3 chief disadvantages of this class of materials: (1) Difficult handling properties, (2) poor resistance to surface wear, and (3) poor resistance to fracture. They have produced products that are improved to the point that these major disadvantages have either been eliminated or reduced to acceptable levels.[3]

The fascination for research on metal free restorations has risen considerably in the past 20 years.[11] The introduction of ZrO2 as a metal free, “ALL” ceramic option opened a new horizon for restorative dentistry with unlimited possibilities and virtually no limitations.[12] ZrO2 is alluring due to its good mechanical properties, aesthetics and low plaque accumulation. It was introduced by Martin Heinrich Klaproth in 1789. This material is a noncytotoxic metal oxide, is insoluble in water and has no potential for bacterial adhesion. In addition, it has radiopaque properties and exhibits low corrosion.[11] These elements of ZrO2 led to the formulation of ZrO2 infused GIC to enhance the strength and aesthetics of GICs. “Zirconomer,” is a GIC infused with esthetic ZrO2 which has the potential to enhance its mechanical properties as well. The improvement can only be assessed by comparing it with the gold standard “conventional GIC.”

Aesthetic dentistry imposes several demands on the artistic abilities of the dentist and knowledge on the underlying scientific principles of color is essential. Color combination not only improves esthetics but also makes the restoration appear natural and attractive.[1]

It is known that color selection by the human eye is subjected to bias. This is due to specific elements, such as the observer's clinical perception and illumination of the environment and of the object.[8] The rationale behind selecting digital method for color analysis is that it is more precise and consistent than human vision because it can analyze color without human influence bias.[13],[14]

In the current study, ZrO2 infused GIC surpassed the conventional GIC in terms of color stability, but conventional GIC has vanquished the former with respect to color match and surface texture. We did come across few drawbacks with respect to Zirconomer restorative material, which are, poor working consistency, longer setting time than conventional GIC, rough surface texture and nonblending with the tooth color.

In a study conducted by Gu et al., where amalgam alloy in miracle mix was replaced by yttria stabilized ZrO2 particles, mechanical properties of ZrO2 infused miracle mix were found to improve with increased soaking time and tensile strength was found to be greater than the amalgamated miracle mix.[7]

In another study by Gu et al. on the effect of incorporation hydroxyapatite (HA)/ZrO2 particles, there was a uniform distribution of these particles in the GIC matrix and mechanical properties were found to be better than HA GICs. They also observed the deterioration of mechanical properties with an increase in HA/ZrO2 content in the GIC above 12 vol%.[15]

The higher opacity in ZrO2 infused restorations in our study could be attributed to increased ZrO2 by vol% in the GIC leading to the debacle of ZrO2 infused GIC, though the increase in poor surface texture over a period of 3 months is unknown.

 Conclusions



Within the limitations of this study, it can be concluded that conventional GIC is better than ZrO2 infused GIC in terms of color match and surface texture. However, further research is needed to opine fully on ZrO2 infused GIC.

 Acknowledgments



We would like to thank Dr. Basappa. N and Dr. Saraswathi Naik for evaluating the restorations in this clinical study and Mr. Vinayak for formulating the statistics for this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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