Journal of International Oral Health

: 2020  |  Volume : 12  |  Issue : 3  |  Page : 203--212

Clinical evaluation of glass ionomer with glass hybrid technology versus conventional high viscosity glass ionomer in class I cavities in patients with high caries risk: Randomized controlled trial

Mohamed Refaat El-Bialy, Omar Osama Shaalan, Ahmad Abdelfatah El-Zohairy, Amira Farid El-Zoghby 
 Department of Conservative Dentistry, Faculty of Dentistry, Cairo University, Cairo, Egypt

Correspondence Address:
Dr. Omar Osama Shaalan
35 Mohamad Farid Street El Hay El Motamayz, Sixth of October City, Giza.


Aim: Glass ionomer is a well-known name in caries management and control. Meanwhile, the dark side in its history is being limited as an interim restoration inside patient mouth. The recently introduced glass ionomer with glass hybrid technology could be a new breakthrough in its future. The aim of this study was to evaluate the clinical performance of glass hybrid glass ionomer compared to conventional high-viscosity glass ionomer in class I cavities in patients with high caries risk. Materials and Methods: In a split-mouth design, 31 high caries risk patients with class I cavities received randomly two pairs of restorations, either EQUIA Forte (glass ionomer with glass hybrid technology) or EQUIA Fil (conventional high-viscosity glass ionomer); both materials were applied according to manufacturer’s instructions. Restorations were evaluated at baseline (1 week) and after 1 year by two blinded assessors using Federation Dentaire Internationale criteria for assessment of dental restoration measuring (functional properties and biological properties). Results: Chi-square test was used to compare the difference between glass-ionomer restorative materials at the base line and after 1 year. A value of P ≤ 0.05 was considered statistically significant. There was no statistically significant difference between both materials for all tested outcomes with 100% success rate (score 1 or 2). Conclusion: Glass hybrid glass-ionomer restoration has shown clinical performance similar to conventional high-viscosity glass-ionomer restoration in class I cavities in patients with high caries risk after 1 year of clinical service.

How to cite this article:
El-Bialy MR, Shaalan OO, El-Zohairy AA, El-Zoghby AF. Clinical evaluation of glass ionomer with glass hybrid technology versus conventional high viscosity glass ionomer in class I cavities in patients with high caries risk: Randomized controlled trial.J Int Oral Health 2020;12:203-212

How to cite this URL:
El-Bialy MR, Shaalan OO, El-Zohairy AA, El-Zoghby AF. Clinical evaluation of glass ionomer with glass hybrid technology versus conventional high viscosity glass ionomer in class I cavities in patients with high caries risk: Randomized controlled trial. J Int Oral Health [serial online] 2020 [cited 2020 Aug 4 ];12:203-212
Available from:

Full Text


Restorative treatment of dental caries in posterior teeth dictates meeting the function needed without sacrificing biology while providing satisfactory esthetics. For treatment of cavities in stress-bearing areas resulting from occlusal pits and fissure caries, resin composite could be considered the gold standard material for treatment in general.[1] However, in vivo plaque studies assessing the level of cariogenic bacteria invariably showed significant lower levels of caries-associated microorganisms adjacent to glass ionomer compared to either resin composite or even amalgam restorations.[2],[3]

Glass ionomer could be the restoration of choice in patients with high caries risk as it inhibits cariogenic bacteria that cause demineralization at tooth-restoration interface.[4] It also provides good sealing to cavity walls as it can chemically bond to dentin through ionic bond with hydroxyapatite in addition to the fluoride release and rechargability, which plays an important role in caries prevention.[5]

Early generations of glass-ionomer cements had relatively poor mechanical properties and wear resistance in addition to high initial solubility, whereas the newer generations of high-viscosity glass-ionomer (HVGI) cements have improved mechanical properties and provide higher levels of fluoride release as compared with traditional glass-ionomer cements.[6]

A new material was introduced to the market, known as glass ionomer, with an innovative glass hybrid technology (GHGI), which builds up a much stronger matrix structure with great physical properties, wear resistance, and fluoride release, which allow extended indications of use even in stress-bearing areas as compared to its predecessor.

With the limited evidence-based information in literature about glass-ionomer restorations with glass hybrid technology, it was found beneficial to evaluate the clinical performance of this newly introduced restorative material using a randomized controlled clinical trial to test the null hypothesis that GHGI will have the same clinical performance as conventional HVGI in class I cavities of patients with high caries risk.

 Materials and Methods

All procedures performed in this study were in accordance with the ethical standards of Research Ethics Committee of Faculty of Dentistry, Cairo University, Cairo, Egypt (Ref. no. 16/09/02). Informed consent was obtained from all participants. A protocol was registered in results database “NCT02856932.”

The sample size was calculated using PS (Power and Sample Size Calculation) software, version 3.1.2 for Windows, William D. Dupont and Walton D. Plummer, Nashville, TN, USA based on the previous study,[7] which indicated that the success rate among controls was 0.32. If the true success rate for experimental subjects was 0.67, it was needed to study 31 case patients in each group to be able to reject the null hypothesis that the failure rates for experimental and control subjects are equal with probability (power) 0.8. The probability of Type I error associated with this test of this null hypothesis was 0.05. An uncorrected chi-square statistic was used to evaluate this null hypothesis.

Eligibility criteria of participants

Inclusion criteria of participants were patients with bilateral occlusal class I carious lesions, aged 19–50 years; those with high caries risk; and those who were willing to participate in the study. Exclusion criteria of participants were systemic disease or severe medical complications; pregnancy; disabilities; heavy smoking; lack of compliance; and evidence of severe bruxism, clenching, or temporomandibular joint disorders.

Eligibility criteria of teeth

Inclusion criteria of teeth were class I carious lesion in occlusal pits and fissures; cavity preparation should not exceed 1/3 intercuspal distance, functioning with the presence of an opposing and healthy periodontium. Exclusion criteria of the teeth were deep carious defects indicated for partial caries removal; periapical or pulpal pathology; tooth hypersensitivity; nonfunctioning teeth with no opposing dentition; heavy occlusion or signs of severe attrition; endodontically treated teeth; and severe periodontal affection.

Recruitment of participants

Patients were enrolled 1 month before the intervention from Faculty of Dentistry, Cairo University. Eligible participants were recruited to fulfill the eligibility criteria [Figure 1]. Patients who agreed to participate in this study signed an informed consent form.{Figure 1}

Allocation of participants

Simple randomization was done using coin toss (head or tail), assigning materials either to the right or left sides randomly in a split-mouth design with allocation ratio 1:1. The operator chose from an opaque sealed envelope to reveal the material assignment, which was arranged by the assistant, who was not involved in any of the phases of the clinical trial. The operator was not blinded to the material assignment because of the difference in the application protocol of the restorative materials; however, the assessors and participants were blinded to the material assignment.

Caries risk assessment

Participants who had two or more cavitated carious lesions with at least one risk factor from the risk factors declared by CAMBRA (Caries Management By Risk Assessment) were considered patients with high caries risk.[8],[9]

Cavity preparation

Patients were given local anesthesia as required; assessment of centric occlusal stops was performed with articulating paper prior to cavity preparation. No. #245 (MANI, Tochigi, Japan) bur (0.8 mm in diameter and 3 mm in length) in a high-speed handpiece with copious air and water coolant was used to prepare class I cavity preparations, with buccolingual width not exceeding 1/3 intercuspal distance. Sharp excavators of suitable size were used to excavate soft carious lesions in dentin.

Material’s application

The cavity to be restored was isolated with cotton rolls in addition to saliva ejector to absorb saliva. They were changed regularly once it became saturated with saliva. Restorative procedure was done with the patients placed in a semi-supine position to allow maximal control of salivary flow. After tooth preparation, Dentin Conditioner (GC Corporation, Tokyo, Japan) was applied for 20s using micro-applicator and then cavity was rinsed thoroughly with water. Dryness of the cavity was done by blotting away excess water by gently blowing with an air syringe without desiccation (chalky white appearance) and the prepared surfaces appeared moist (glistening). After cavity conditioning, coin toss was performed to randomly assign interventions to right or left sides. All materials were applied according to manufacturer’s instructions [Table 1].{Table 1}

All restorations were finished with superfine yellow ringed finishing diamond stones under copious water coolant. Checking of any occlusal prematurities in both centric and eccentric occlusion was performed through both patients’ sensibility and marking by articulating paper. After finishing, immediate application of the coat assigned to each material was performed using the disposable micro-tip applicator and light cured with light-emitting diode light-curing unit (1000 mW/cm²) for 20s. Federation Dentaire Internationale (FDI) criteria (functional and biological) were used to evaluate dental restoration by two blinded assessors at baseline and after 1 year [Table 2] and [Table 3].{Table 2}, {Table 3}

Statistical analysis

Data were analyzed using the Statistical Package for the Social Sciences software, version 19.0 (IBM, Armonk, New York). Chi-square test was used for comparison of all qualitative outcome data. A value of P ≤ 0.05 was considered statistically significant.


The results of this study have revealed no statistically significant difference between both materials for all tested outcomes at baseline and after 1 year. [Table 4] shows frequency (n) and percentage of outcomes assessed according to FDI criteria for assessment of dental restorations. After 1 year, all restorations were evaluated with no dropouts. The success rate regarding functional and biological properties was 100% [Figure 2]. GHGI has shown clinical performance similar to conventional HVGI after 1 year of clinical service; therefore, the null hypothesis was accepted.{Table 4}, {Figure 2}


In vitro studies showed that both auto-cure and resin-modified glass-ionomer cements protect the margins of restorations from caries up to depths of 0.25 mm, whereas composite resins do not.[3],[10] Moreover, the glass-ionomer material is the only restorative material able to bond to all parts of the tooth and carious tooth structure[11] with a high degree of reliability and low-technique sensitivity.[12]

Injectable restorative materials such as glass-ionomer cements and flowable composites provide excellent handling characteristics using an injection delivery system, which overcomes some of the obstacles encountered during the placement of restorative materials, especially in inaccessible areas. Nevertheless, their clinical applications have been restricted to some degree by their mechanical shortcomings found in early generations. Recently, their mechanical properties had been enhanced after new innovations in such materials, allowing them to attain or overcome some conventional restorative materials. Moreover, their fluidity provides better adaptation to the inner walls and cervical region, besides an easier clinical placement so they may become materials of universal indication.[13],[14]

In March 2015, GHGI was launched and termed in the literature as glass hybrid GIC. It is considered the first glass-ionomer restorative material recommended by the manufacturer to be used in stress-bearing occlusal cavities even in cavities with proximal surface involvement. Also, it is known as thermo-setting GICs as GHGI uses a radiant heat derived from curing light to accelerate the set.[15]

GHGI is the product combining a self-adhesive, chemically cured, highly filled glass-ionomer cement with a self-adhesive, light-cured, filled resin surface coating. The manufacturers of this system claimed increased fracture toughness, flexural strength, and flexural fatigue resistance as compared to conventional glass-ionomer materials.[16] GHGI is a complete glass-ionomer-based, bulk-fill, rapid restorative system, which is easy to use and allows a quick placement. Also, it is a reinforced GIC, with a second, smaller, and more reactive silicate particle and higher-molecular-weight acrylic acid molecules, which supposedly increase matrix cross-linking. The material could be applied without conditioner or adhesive.[15] Although there is no enough evidence regarding its clinical performance and biocompatibility,[17] GHGI provides a significant additional mineral gain in residual carious lesions as compared to pulpal mineral provision only.[18]

In this study, after 1 year all restorations were evaluated with no dropouts, the success rate regarding functional and biological properties was 100%. In this study, GHGI has shown clinical performance similar to conventional HVGI after 1 year of clinical service; therefore, the null hypothesis was accepted.

The randomized controlled trials (RCTs) are considered to be the highest level of evidence that could be applied.[19] Hierarchy of evidence is arranged in an evidence pyramid with an increasing order of internal validity, or a freedom from bias, from bottom to top. In vitro and animal studies are placed at the lowest level, followed by opinions, case reports, and observational studies. RCTs, systematic reviews, and meta-analyses are placed at the top of the pyramid, representing the highest level of available evidence.[13],[20]

Patients with high caries risk were selected in this study in order to test material in challenges such as pH fluctuation, high sugar intake, increased bacterial load, or lower salivary secretion in such cases. Besides being recommended to use conventionally setting glass ionomers in such patients, it showed higher protection against secondary caries than resin composite or resin modified glass ionomer, even after loss of the filling material.[7],[21] Moreover, it was found that caries risk does not influence survival of glass-ionomer sealants, which proved to be beneficial for long-term caries protection.[22]

FDI criteria[23] for evaluation of dental restorations had been developed, which is a more sensitive and discriminative scale than the modified United States Public Health Services (USPHS) criteria based on three criteria categories: aesthetic, functional, and biological. Each category was divided into subcategories to allow for more detailed description and analysis. Each subcategory was scored according to a 5-step grading of the restoration: score 1––the restoration is excellent and fulfills all quality criteria; score 2––the restoration is still highly acceptable, though one or more criteria deviate from the ideal with no risk of damage; score 3––the restoration is sufficiently acceptable but with minor shortcomings and does not need any intervention; score 4––the restoration is unacceptable but repairable; and score 5––the restoration has to be replaced.[24]

In this study, the functional and biological properties were the only selected criteria for assessment, as the materials used in non-visible areas such as molars, the esthetic properties can be dropped, as esthetics issues are of low interest compared with anterior restorations.[25]

Assessment of the restorations was selected to be after 1 week as a baseline assessment and after 1-year follow-up.[23] Baseline evaluation after 1 week provided enough time for maturation of glass-ionomer material and resolution of any sensitivity or discomfort due to restorative procedural technique. The recalls could be either taken place after 6 months or preferably can be yearly recalls. An annual survival rate is recommended as it is more easily calculated from other options.[23] In a previous study, annual failure rates of glass ionomer as a posterior restorations were 20% higher than that estimated from retrospective clinical trials.[26] One year could provide some information about the clinical performance of glass ionomer, and this period was enough for primary evaluation of success or failure regarding the functional and biological properties assessed in this study.[23]

Regarding the functional scores, four items were analyzed: fracture and retention; marginal adaptation; occlusal contour; and wear plus patient’s view. Regarding the biological scores, four items were also analyzed: postoperative hypersensitivity; recurrence of caries; tooth integrity; and oral and general health. Overall scores, either overall functional properties or overall biological score, were determined by the subcategory scores, with the final score in each group being dictated by the most severe score among all the subscores.[25] The least score detected among all groups in both restorative materials after both follow-up periods was 2 (clinically good), making all restorations clinically successful with at least clinically good grading.

Regarding the fracture and retention results, small hairline crack was detected in only two restorations in control group after 1 year with no statistically significant difference, which could be a result of excessive occlusal loads, which varies from individual to another and even in the same individual or a procedural error in cavities preparation.[27]

For marginal adaptation, only one restoration in the control group showed score 2 in both time intervals, whereas three restorations in GHGI material showed score 2 after 1 year only, with no statistically significant difference between all groups. This could be as a result of the increased viscosity of the new material, which could affect adaptation of the material to cavity walls and margins, which dictates further investigations.[28]

Regarding the occlusal contour and wear, four restorations of GHGI showed score 2, where two of them showed the same score at the start of the study. Likewise, two restorations of the control group scored 2, where one of them scored the same at the start of the study with no statistical significance in all comparisons. As a result of difficulty in manipulating glass ionomers due to its stickiness, different techniques were introduced in order to adapt glass ionomers to cavity margins and narrow fissure sealant preparations. However, a difficulty was still found in its contouring, especially in fast set types as compared to resin composite, which offers a command set and less sticky nature.[29]

Regarding the patient’s view, all restorations showed score 1, which was due to the acceptance of shade gained by glass ionomer for the patients, especially in non-obviously visible posterior teeth. Moreover, the simplicity of the procedure noticed for performing glass-ionomer restorations could be not only satisfying for the patients but also could be considered the secret of the spread of encapsulated glass ionomer among dental practitioners.[12]

Regarding the biological properties, the results of tooth integrity showed 100% success rate with score 1 for both restorative materials after 1 year. This could be due to selection of the cavities and cavity design, with no weak cusps or undermined enamel and this matches the results of Ruengrungsom et al.,[30] in addition to the nature of chemical bonding obtained in the tooth–glass ionomer interface that shows a reliable support for tooth structure, which is in agreement with that reported by Sidhu and Nicholson.[31]

Moreover, postoperative sensitivity, recurrence of decay, and oral and general health showed 100% success rate with score 1 for both restorative materials after 1 year. This could be explained due to the biocompatibility of glass ionomer and its anticariogenic potential.[12] Only one restoration in both materials showed mild postoperative sensitivity scoring 2 at baseline, which diminished with time and totally disappeared after 1 year. This could be explained due to the initial acidity of glass ionomer, especially in the case of conditioning cavities prior to restorative procedures.[32]

The overall functional properties results showed 100% success rate. This could be attributed to the advancement of the glass ionomer obtained throughout the years. One of the key factors is the high molecular mass of acid polymers, which produced strong cements, in addition to quicker setting than cements made from low molecular mass of acid polymers.[12] Moreover, recent studies showed that, when the particle size of the glass is reduced, the reactivity of the particles is greatly increased with the same glass composition. This also tends to decrease the setting time when nano-granular particles replace the macro-granular particles.[33]

Resin coating of the restorations was done according to manufacturer’s instructions in order to improve the mechanical properties of the restorations. The application of the coating increases the strength of the glass ionomer and increases its abrasion resistance. It is believed that resin is able to infiltrate the glass-ionomer surface, thus filling cracks and porosities.[34] Resin coating protects the glass-ionomer materials from excessive wear making HVGIs to abrade in a similar manner as resin composite. It was also recommended that resin coating protects and makes the HVGI materials as wear resistant as resin composites in clinical situations for a long time.[35]

Moreover, another beneficial effect might be attained from curing of the resin coat, as external heat derived from light curing of resin coat during the setting of glass ionomer could improve the mechanical properties of the material without leading to harmful overheating of the pulp tissue, which might cause pathological conditions. The application of external heat or thermo-curing could be considered as a command set method and a technique for improving mechanical properties and adhesion of glass-ionomer materials, which was advised to be part of regular clinical practice.[36]

There were a very limited data available in the literature for the clinical performance of GHGI. The results of this study were in agreement with those reported by Grossi et al.,[37] which showed a success rate of 98.3% after 6 and 12 months with only one restoration failure. The reason submitted for the failure was involving more than three surfaces and presented as breakdown of all cusps.

The current results were in agreement with those reported by previous studies,[38],[39],[40],[41],[42] which indicated that no restorations had failed after 1 year in posterior permanent molars. In addition, Kharma et al.[43] recommended that HVGI could be a viable alternative to resin composite in restoring class I cavities in permanent teeth

On the contrary, the current results were in disagreement with those reported by Hickel and Manhart,[44] who observed a failure rate of 1.4% after 1 year. This disagreement could be due to the difference in material composition in that time and resin coat application.

Previously, glass ionomer was considered an interim restoration and limited to caries control protocols and considered unreliable for clinical application as a permanent posterior restoration. However, with recent innovations and continued upgrading and developments, glass ionomer might occupy a high rank in the near future opening a new horizon for expanded uses with a reliable performance in different situations.


Under the limitations of this study, the following conclusions could be derived:

Glass-ionomer restorations either with glass hybrid technology or conventional high viscosity have shown excellent clinical performance in simple class I cavities in patients with high caries risk.

GHGI is a successful alternative for other restorative materials indicated for stress-bearing areas in class I cavities especially in patients with high caries risk.

Clinical recommendations

Clinical studies are the last and the most important step to evaluate new materials and techniques; further, long-term clinical studies are required to confirm the current results.

Clinical trials’ testing performance of glass hybrid glass ionomer in other clinical indications is encouraged to recommend using the new material in various clinical applications, especially in stress-bearing areas.

Data availability statement

The data that support the findings of this study are available from the corresponding author, on reasonable request.

Financial support and sponsorship


Conflict of interest

There are no conflicts of interest.


1Ferracane JL. Resin composite––State of the art. Dent Mater 2011;27:29-38.
2Svanberg M, Mjör IA, Orstavik D. Mutans streptococci in plaque from margins of amalgam, composite, and glass-ionomer restorations. J Dent Res 1990;69:861-4.
3Tantbirojn D, Rusin RP, Bui HT, Mitra SB. Inhibition of dentin demineralization adjacent to a glass-ionomer/composite sandwich restoration. Quintessence Int 2009;40:287-94.
4Nassar HM, Platt JA. Effect of brushing with two different abrasives on fluoride release by high-viscosity glass ionomer cement. J Oral Sci 2015;57:379-84.
5Dauvillier BS, Feilzer AJ, De Gee AJ, Davidson CL. Visco-elastic parameters of dental restorative materials during setting. J Dent Res 2000;79:818-23.
6Kunzelmann KH, Bürkle V, Bauer C. Two-body and three-body wear of glass ionomer cements. Int J Paediatr Dent 2003;13:434-40.
7De Moor RJ, Stassen IG, van ‘t Veldt Y, Torbeyns D, Hommez GM. Two-year clinical performance of glass ionomer and resin composite restorations in xerostomic head- and neck-irradiated cancer patients. Clin Oral Investig 2011;15:31-8.
8Cambra HM. Best practices in dental caries management. RDH magazine [Internet]. 2011. Available at: [Last accessed on 2012 Aug 20].
9Jenson L, Budenz AW, Featherstone JD, Ramos-Gomez FJ, Spolsky VW, Young DA. Clinical protocols for Caries Management By Risk Assessment. J Calif Dent Assoc 2007;35:714-23.
10Knight GM, McIntyre JM, Craig GG, Mulyani, Zilm PS, Gully NJ. An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations. Aust Dent J 2007;52:187-92.
11Lenzi TL, Bonifácio CC, Bönecker M, Amerongen WE, Nogueira FN, Raggio DP. Flowable glass ionomer cement layer bonding to sound and carious primary dentin. J Dent Child (Chic) 2013;80:20-4.
12Sidhu SK. Glass-ionomers in Dentistry. Switzerland: Springer International Publishing; 2015.
13Shaalan OO, Abou-Auf E, El Zoghby AF. Clinical evaluation of flowable resin composite versus conventional resin composite in carious and noncarious lesions: Systematic review and meta-analysis. J Conserv Dent 2017;20:380-5.
14Shaalan OO, Abou-Auf E, El Zoghby AF. Clinical evaluation of self-adhering flowable composite versus conventional flowable composite in conservative class I cavities: Randomized controlled trial. J Conserv Dent 2018;21:485-90.
15Schwendicke F, Kniess J, Paris S, Blunck U. Margin integrity and secondary caries of lined or non-lined composite and glass hybrid restorations after selective excavation in vitro. Oper Dent 2017;42:155-64.
16Yasa E, Atalayin C, Karacolak G, Sari T, Turkun LS. Intrapulpal temperature changes during curing of different bulk-fill restorative materials. Dent Mater J 2017;36:566-72.
17Collado-González M, Pecci-Lloret MR, Tomás-Catalá CJ, García-Bernal D, Oñate-Sánchez RE, Llena C, et al. Thermo-setting glass ionomer cements promote variable biological responses of human dental pulp stem cells. Dent Mater 2018;34:932-43.
18Al-Abdi A, Paris S, Schwendicke F. Glass hybrid, but not calcium hydroxide, remineralized artificial residual caries lesions in vitro. Clin Oral Investig 2017;21:389-96.
19Pandis N. The evidence pyramid and introduction to randomized controlled trials. Am J Orthod Dentofacial Orthop 2011;140:446-7.
20Mulimani PS. Evidence-based practice and the evidence pyramid: A 21st century orthodontic odyssey. Am J Orthod Dentofacial Orthop 2017;152:1-8.
21McComb D, Erickson RL, Maxymiw WG, Wood RE. A clinical comparison of glass ionomer, resin-modified glass ionomer and resin composite restorations in the treatment of cervical caries in xerostomic head and neck radiation patients. Oper Dent 2002;27:430-7.
22Markovic D, Peric T, Petrovic B. Glass-ionomer fissure sealants: Clinical observations up to 13 years. J Dent 2018;79:85-9.
23Hickel R, Roulet JF, Bayne S, Heintze SD, Mjör IA, Peters M, et al. Recommendations for conducting controlled clinical studies of dental restorative materials. Science committee project 2/98––FDI world dental federation study design (part I) and criteria for evaluation (part II) of direct and indirect restorations including onlays and partial crowns. J Adhes Dent 2007;9:121-47.
24Marquillier T, Doméjean S, Le Clerc J, Chemla F, Gritsch K, Maurin JC, et al. The use of FDI criteria in clinical trials on direct dental restorations: A scoping review. J Dent 2018;68:1-9.
25Hickel R, Peschke A, Tyas M, Mjör I, Bayne S, Peters M, et al. FDI world dental federation––Clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples. J Adhes Dent 2010;12:259-72.
26Frankenberger R, Garcia-Godoy F, Krämer N. Clinical performance of viscous glass ionomer cement in posterior cavities over two years. Int J Dent 2009;2009:781462.
27Hayashi M, Sugeta A, Takahashi Y, Imazato S, Ebisu S. Static and fatigue fracture resistances of pulpless teeth restored with post-cores. Dent Mater 2008;24:1178-86.
28Agarwal RS, Hiremath H, Agarwal J, Garg A. Evaluation of cervical marginal and internal adaptation using newer bulk fill composites: An in vitro study. J Conserv Dent 2015;18:56-61.
29Knight GM, Sidhu SK. The benefits and limitations of glass-ionomer cements and their use in contemporary dentistry. In: Glass-Ionomers in Dentistry.Switzerland: Springer International Publishing;2016. p. 57-79.
30Ruengrungsom C, Palamara JEA, Burrow MF. Comparison of ART and conventional techniques on clinical performance of glass-ionomer cement restorations in load bearing areas of permanent and primary dentitions: A systematic review. J Dent 2018;78:1-21.
31Sidhu SK, Nicholson JW. A review of glass-ionomer cements for clinical dentistry. J Funct Biomater 2016;7:16.
32Akpata ES, Sadiq W. Post-operative sensitivity in glass-ionomer versus adhesive resin-lined posterior composites. Am J Dent 2001;14:34-8.
33De Caluwé T, Vercruysse CW, Fraeyman S, Verbeeck RM. The influence of particle size and fluorine content of aluminosilicate glass on the glass ionomer cement properties. Dent Mater 2014;30:1029-38.
34Lohbauer U, Krämer N, Siedschlag G, Schubert EW, Lauerer B, Müller FA, et al. Strength and wear resistance of a dental glass-ionomer cement with a novel nanofilled resin coating. Am J Dent 2011;24:124-8.
35Kanik Ö, Turkun LS, Dasch W. In vitro abrasion of resin-coated highly viscous glass ionomer cements: A confocal laser scanning microscopy study. Clin Oral Investig 2017;21:821-9.
36van Duinen RN, Shahid S, Hill R, Glavina D. In-vitro study on temperature changes in the pulp chamber due to thermo-cure glass ionomer cements. Acta Stomatol Croat 2016;50:287-91.
37Grossi JA, Cabral RN, Ribeiro APD, Leal SC. Glass hybrid restorations as an alternative for restoring hypomineralized molars in the ART model. BMC Oral Health 2018;18:65.
38Gurgan S, Kutuk ZB, Ergin E, Oztas SS, Cakir FY. Four-year randomized clinical trial to evaluate the clinical performance of a glass ionomer restorative system. Oper Dent 2015;40: 134-43.
39Vaid DS, Shah NC, Bilgi PS. One year comparative clinical evaluation of EQUIA with resin-modified glass ionomer and a nanohybrid composite in noncarious cervical lesions. J Conserv Dent 2015;18:449-52.
40Klinke T, Daboul A, Turek A, Frankenberger R, Hickel R, Biffar R. Clinical performance during 48 months of two current glass ionomer restorative systems with coatings: A randomized clinical trial in the field. Trials 2016;17:239.
41Yip KH, Smales RJ, Gao W, Peng D. The effects of two cavity preparation methods on the longevity of glass ionomer cement restorations: An evaluation after 12 months. J Am Dent Assoc 2002;133:744-51; quiz 769.
42Gurgan S, Kutuk ZB, Ergin E, Oztas SS, Cakir FY. Clinical performance of a glass ionomer restorative system: A 6-year evaluation. Clin Oral Investig 2017;21:2335-43.
43Kharma K, Zogheib T, Bhandi S, Mehanna C. Clinical evaluation of microhybrid composite and glass ionomer restorative material in permanent teeth. J Contemp Dent Pract 2018;19:226-32.
44Hickel R, Manhart J. Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent 2001;3:45-64.