Clinical evaluation of bioactive composite resin in class V lesions in high-risk caries patients: A randomized split-mouth trial

Abstract

Background:

Recurrent caries at tooth–restoration interfaces remains a primary reason for restoration replacement. The challenge is developing biomaterials that prevent demineralization or promote remineralization. The study aimed to clinically evaluate and compare bioactive composite resin (CR), Predicta Bioactive Bulk, and nonbioactive CR in class V lesions of high-risk caries patients using the FDI criteria.

Subjects and Methods:

Twenty high caries risk adult patients with bilaterally symmetrical posterior buccal caries were selected. Restorations with either Predicta Bioactive composite or nonbioactive composite were undertaken and recalled for clinical evaluation at baseline (1 month), 3, 6, and 12 months using the FDI criteria. The data were analyzed using the SPSS software (Windows Version 22.0, Released 2013). Mean, standard deviation, frequency, proportions, Chi-square test, Cochran’s Q test, and McNemar’s post hoc test were assessed at P < 0.05 significance.

Results:

There were no statistically significant differences in the clinical performance of bioactive and nonbioactive composites in terms of marginal staining, fracture and retention, marginal adaptation, and recurrence of initial pathology.

Conclusion:

Predicta Bioactive Bulk and 3M™ Filtek™ Bulk Fill Posterior Restorative demonstrated equivalent effectiveness in the restoration of class V caries in high-risk caries patients.

INTRODUCTION

Dental caries, a multifactorial ailment, impacts a substantial portion of the global population, recognized as the most prevalent chronic condition. There is not a singular solution for curing dental caries but a delicate balance between pathological and preventive factors.

Previous studies show that dental caries distribution is higher on occlusal surfaces than class V areas.[1] Unlike intricate fissures and grooves present on occlusal surfaces, smooth tooth surfaces lack a conducive anatomical environment for the formation of complex, organized microorganism communities. Caries-prone areas on free smooth surfaces are mainly below the equatorial line, specifically the cervical third near the gum line. Restoring cervical defects is a routine procedure in restorative dentistry.

Composite resins (CRs) are favored for cervical restoration due to appealing esthetic qualities and mechanical characteristics. However, they do possess certain drawbacks, notably polymerization shrinkage and a high modulus of elasticity, which can lead to stress under occlusal forces.[2] As researchers seek alternatives to CR, studies indicate a growing preference for glass ionomer cement (GIC). This is attributed to their similarity in modulus of elasticity to dentin and their fluoride-releasing properties. Nevertheless, certain past studies have expressed doubts regarding the efficacy of GIC and RMGIC in preventing demineralization and fostering enamel remineralization within clinical contexts. However, they exhibit inferior esthetic qualities due to translucency and limited color choices.[3]

Therefore, there is a necessity for materials that combine the advantages of composites and GIC. A new bioactive material called Predicta Bioactive (Parkell, NY, USA), a bulk-fill dual-cure resin composite, has been developed with high compressive, tensile, and flexural strengths for both direct and indirect restorations forming a robust bond with tooth by sealing interfacial microgaps and safeguarding against microleakage.[4]

The functional, esthetic, and biological performance of these materials needs evaluation. It is imperative to conduct controlled randomized clinical trials using widely accepted evaluation systems to establish robust evidence-based dental knowledge and inform restorative practices effectively.

To our knowledge, no prior studies have investigated the clinical performance of bioactive composites, namely Predicta in class V lesions of high-risk caries patients.

This study aimed to clinically evaluate and compare bioactive CR, Predicta Bioactive Bulk (Predicta, Parkell™), and nonbioactive CR, 3M™ Filtek™ Bulk Fill Posterior Restorative (3M, ESPE™) in class V lesions of high-risk caries patients using the fédération dentaire internationale (FDI) criteria.

SUBJECTS AND METHODS

The protocol of this study was approved by the Ethics Committee of Kempegowda Institute of Medical Sciences (KIMS/IEC/D020/D/2022) and, with the Helsinki Declaration of 1975, revised in 2008, with Clinical Trials Registry – India ID No. CTRI/2023/03/051088. Strict adherence to Consolidated Standards of Reporting Trials (CONSORT) was maintained.

Twenty adult patients aged 18–60 years participated in this randomized double-blind split-mouth clinical trial after informed consent was chosen from the pool of patients referred to the department of conservative dentistry and endodontics. The flowchart is depicted in Figure 1.

Figure 1.

Flow diagram of recruitment, allocation and number of restorations available for analysis

The study included patients aged 18–60 years who had at least two nonsymptomatic posterior teeth with buccal Class V carious lesions showing distinct cavitation and visible dentin. These patients were classified as high caries risk based on the American Dental Association’s Caries Risk Assessment (CRA) guidelines (age >6), which consider individuals with three or more carious lesions or restorations (either cavitated or noncavitated/incipient, detected visually or radiographically) in the past 36 months. Teeth with noncarious cervical lesions, discoloration, developmental defects, or pathological mobility and patients with parafunctional habits were excluded from the study.

The teeth selected were randomly allocated using a digital randomizer software into two groups based on the nature of composite used for restoration which are:

• Group 1 – Bioactive CR, Predicta Bioactive Bulk (Predicta, Parkell™)

• Group 2 – Nonbioactive CR, 3M™ Filtek™ Bulk Fill Posterior Restorative (3M, ESPE™).

Isolation was achieved using a rubber dam and No. B5 retainer. Initial tooth preparation involved a round carbide bur #3 (SS White) to eliminate lesions. Enamel margin was beveled using a flame-shaped diamond bur #22F (Mani) at a 45° angle and a width of 0.5 mm to the external tooth surface at the occlusal margin.

Selective etching of enamel margins was carried out with 35% phosphoric acid etching gel (3M Espe Scotchbond Universal Etchant Syringe) for 15 s followed by a 20 s air/water spray and drying, leaving the dentin moist. Single Bond™ Universal (Single Bond™ 3M Deutschland GmbH, Neuss, Germany) was applied according to the manufacturer’s instructions and light-cured for 20 seconds using an Ultradent Valo LED curing light at an intensity of 1200 mW/cm².

In G1 teeth, Predicta® Bioactive Bulk-Fill was applied according to the manufacturer’s instructions. In G2 teeth, after following the same bonding protocol as G1, restoration with 3M™ Filtek™ Bulk Fill Posterior Restorative was done using an incremental layering technique of increment of 2.5 mm will be cured for 20 s. Flat No. 2 sable brush is used for removing excess material from the cervical margin and obtaining the final contour. Finishing and polishing were done using polishing discs (Super-Snap Mini Kit, Shofu).

Patients were recalled for assessment and evaluation at baseline (1 month), 3, 6, and 12 months using the FDI criteria by two blinded investigators. Evaluations were conducted under magnification (Admetec Ergo loupes, ×5, Admetec, Israel) with an exploratory probe. Out of the total of 16 criteria, 4 were evaluated using the FDI criteria:[5] marginal staining, fracture and retention, marginal adaptation, and recurrence of initial pathology and scored accordingly. Results were tabulated in Excel and analyzed.

Data were analyzed using the Statistical Package for the Social Sciences (SPSS) for Windows Version 22.0, Released 2013, Armonk, NY, USA: IBM Corp., and the level of significance was set at P < 0.05. Descriptive analysis of all explanatory and outcome parameters was done using mean and standard deviation for quantitative variables and frequency and proportions for categorical variables. The interobserver agreement was assessed via Cohen’s kappa. Inferential statistics included the use of the Chi-square test to compare study parameters between the two groups at different time intervals and Cochran’s Q test followed by McNemar’s post hoc test to compare study parameters between different follow-up time intervals.

RESULTS

The FDI scores at baseline, 3, 6, and 12 months were recorded. Table 1 shows that two observers independently reviewed the results, and interobserver agreement assessed using Cohen’s kappa statistic demonstrated substantial agreement (κ = 0.78, P < 0.001). Table 2 compares the FDI criteria evaluations. The results showed no marginal staining in both the groups from baseline to 12 months. Fracture and retention: restorations remained intact without deficiencies, cracks, chipping, or bulk fractures in both the groups from baseline to 12 months. Marginal adaptation: ideal marginal adaptation with no detectable gaps in both the groups from baseline to 12 months. Recurrence of initial pathology: no caries or demineralization at the restoration margins in both the groups from baseline to 12 months. No significant differences were observed between the groups for all criteria assessed.

Table 1.

Overall interobserver agreement among two observers assessed using Cohen’s kappa method, showing agreement percentage, Cohen’s Kappa (κ)

Overall interobserver agreement
Number of observers	Method used	Agreement (%)	Cohen’s Kappa (κ)	P
2	Cohen’s kappa	91	0.78	<0.001

Table 2.

Comparison of the FDI criteria for evaluation of restorations between two groups at different time intervals

Comparison of the FDI criteria for evaluation of restorations between two groups at different time intervals
Time	FDI scores	Baseline			3 months			6 months			9 months
		Group 1, n (%)	Group 2, n (%)	P	Group 1, n (%)	Group 2, n (%)	P	Group 1, n (%)	Group 2, n (%)	P	Group 1, n (%)	Group 2, n (%)	P
Marginal staining	Excellent	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)
	Good	0	0		0	0		0	0		0	0
	Sufficient	0	0		0	0		0	0		0	0
	Unsatisfactory	0	0		0	0		0	0		0	0
	Poor	0	0		0	0		0	0		0	0
Marginal adaptation	Excellent	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)
	Good	0	0		0			0	0		0	0
	Sufficient	0	0		0			0	0		0	0
	Unsatisfactory	0	0		0			0	0		0	0
	Poor	0	0		0			0	0		0	0
Marginal gaps	Excellent	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)
	Good	0	0		0	0		0	0		0	0
	Sufficient	0	0		0	0		0	0		0	0
	Unsatisfactory	0	0		0	0		0	0		0	0
	Poor	0	0		0	0		0	0		0	0
Recurrence of initial pathology	Excellent	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)	20 (100)	20 (100)	1.00 (NS)
	Good	0	0		0	0		0	0		0	0
	Sufficient	0	0		0	0		0	0		0	0
	Unsatisfactory	0	0		0	0		0	0		0	0
	Poor	0	0		0	0		0	0		0	0

NS: Not significant, FDI: Fédération dentaire internationale

DISCUSSION

Dental caries is one of the oldest and most widespread conditions affecting humans, a current, habitual, contagious condition caused by cariogenic bacteria that cleave to teeth, metabolizing sugars to produce acid, leading to demineralization. The prevalence rate of cervical caries in adults (43%–63%) and the incidence has increased due to several possibilities of risk indicators for caries. These are the result of chronic plaque accumulation at the cervical third of the tooth in conjunction with significant intake of fermentable carbohydrates. In addition, reduction in salivary flow and changes in salivary quality due to xerostomia contribute to a high risk of caries.[6]

An integrated disease management approach has been recommended. Bioactive restorative materials offer therapeutic effects combining the benefits of glass ionomers and composites. These include resin-modified GICs (RMGIs), compomers (polyacid-modified composites), giomers, and, more recently, bioactive resin composites.[7] One such bioactive composite is universal, dual-cure composite, Predicta® Bioactive Bulk which releases phosphate and calcium with release and recharge of fluoride ions to stimulate mineral apatite formation and remineralization at the material–tooth interface.

Clinical trials serve as the definitive evaluation for determining the effectiveness of restorative materials. During the study, no ethical issues were encountered. Patient consent was obtained, and all measures were taken to ensure that ethical standards were upheld. The following study is of the split-mouth design, minimizing interindividual variability. Randomization was used with a digital randomizer software. Double-blinding reduced bias per the CONSORT guidelines.

The study has shown that the CRA tool is more effective at identifying low-risk patients than high-risk ones, making it challenging to target preventive measures accurately. Recent evidence has revealed that the “risk level of caries” plays a pivotal role in the survival of posterior composite restorations.[8] The distribution of cervical lesions, most commonly observed in the posterior region in conjunction with increased failure of cervical adhesive restorations, is frequently linked to insufficient moisture control, adhesion to diverse substrates (enamel and dentin), variations in dentin composition, and the movement of cusps during occlusion.[9] Both the diagnosis using CRA tool and the inclusion of class 5 carious lesions in posterior teeth in high-risk individuals with the exclusion of patients with parafunctional habits are justified in the current study.

Studies have shown that pretreating selective enamel before applying self-etch adhesive systems in cervical areas may enhance the clinical effectiveness of resin-composite cervical restorations.[10] In terms of retention, the seventh-generation adhesives outperformed adhesives from other generations[11] which substantiates the adhesive protocols of the current trial.

The restorations were evaluated at baseline, 3, and 6 months, and after 1 year using the revised FDI criteria, this criterion was considered to have moderate to substantial overall reliability with higher sensitivity in assessing marginal staining and marginal adaptation, but it appears to be less conservative, indicating a higher level of restorations replacement.[4] These criteria were used by evaluation with the exclusion of certain categories as followed in a previous study.[12] While long-term follow-up is crucial for assessing the clinical performance of restorative materials, short-term clinical data can also provide valuable insights.

The materials, bioactive composite, Predicta, and nonbioactive composite, 3M Filtek Bulk Fill Posterior, have shown that Predicta bulk bioactive material demonstrated superior interfacial adaptation with minimal microgap formation. Its dual-cure capability allows Predicta restorative to achieve high compressive, tensile, and flexural strengths when placed in bulk. In addition, it releases calcium, phosphate, and fluoride ions, promoting apatite mineral formation and potentially blocking microgaps. They exhibit minimal shrinkage during polymerization, enhancing the interfacial adaptation. With its remineralizing properties, Predicta can reduce postoperative sensitivity, prevent secondary caries, seal restoration margins against microleakage, and improve the durability of the restoration.[13]

The clinical success of restorations depends on caries risk, the quality of the restorative material, size and location of restoration, parafunctional habits, and skills of the operator.[14] Both bioactive and nonbioactive composites showed similar successful clinical performance when used to restore buccal caries in posterior permanent teeth of high caries risk patients, with a 100% survival rate after 1 year. Similar findings were observed in comparative evaluation studies with other bioactive composites.[15,16] The success was attributed to Predicta’s ionic resin component, containing phosphate acid groups with antimicrobial properties which enhance the interaction between resin and reactive glass fillers, improving bond with tooth structure. In the presence of water, hydrogen ions separate from phosphate groups through ionization and are replaced by calcium from the tooth. This ionic interaction bonds restoration to tooth, fills microgaps, reduces sensitivity, and protects against secondary caries by forming a strong resin-apatite complex. The findings of this study are similar to those reported for Class II restorations. While survival rates varied widely between 23% and 97.7%, success rates ranged from 43.4% to 98.7%.[17] The differences in results may be attributed to the relatively short follow-up period.

From baseline to the 12-month follow-up period, both Group 1 and Group 2 showed no significant differences in terms of marginal staining and adaptation. In vitro studies corroborate these findings with Predicta showing the least interfacial gap percentages owing to the theory that bioactive composites facilitate ion diffusion through the bonded interface, thereby increasing matrix-to-mineral ratio and minimizing nanoleakage.[18] Contrastingly, some studies have reported increased microleakage and marginal gap formation upon immediate observation. However, when sample teeth were placed in favorable ionic conditions, excellent results were observed. This highlights that the performance of bioactive composites and marginal characteristics are influenced not only by the intrinsic properties of the composite but also by the environment in which the restoration is placed, namely saliva.[19] The positive results seen in the control group can be attributed to the bulk-fill capability of the material. Volume analysis and shrinkage stress measurements showed a significant reduction in polymerization shrinkage stress, which in turn led to a diminished interfacial gap.

For fracture of material and retention to be provisionally accepted as a restorative material, ADA requires that the cumulative incidence of failure must be <5% at 6-month recall and <10% at 18-month recall.[20] There was no significant difference between the two groups on the basis of fracture of material and retention which depend on both mechanical properties and polymerization stress. Heymann et al. found that materials with a lower elastic modulus were better retained in cervical lesions than those with a higher elastic modulus. Materials with higher elastic modulus cannot deform with the tooth during occlusal stress, resulting in a higher rate of restoration displacement.[21] This could be the reason for future follow-up since the elastic modulus of Predicta ranged at 4.32 ± 0.40 Gpa[22] when contrasted to 17.2 Gpa[23] of Filtek™ Bulk Fill Posterior Restorative.

After 1 year, both restorative materials achieved a 100% success rate in terms of biological properties and the absence of decay recurrence. This success could be attributed to the cavity design, which avoided undermined enamel, biocompatibility of the materials, and superior sealing properties of Predicta. Contradicting reports suggest Predicta’s weak fluoride ion release properties which were comparable to other nanohybrid restorative material indicating its ineffectiveness in preventing caries.[24] However, on assessment of the same in terms of percentage of surface microhardness and mineral deposition in primary molars shows superior results when compared to Filtek Z350, thus concluding Predicta as an alternative restorative material to remineralize adjacent initial interproximal enamel carious lesions in primary molars, especially in high-risk caries patients.[25]

As per the American Dental Association guidelines, a restorative material intended for posterior teeth must maintain a retention rate of at least 90% after 18 months of clinical service to be considered a definitive restorative material. In this study, which spanned 12 months, both the groups achieved a retention rate of 100%.

This study is a clinical split-mouth study garnering its validity ahead of in vitro studies. The design may result in biased estimates of treatment efficacy due to carryover effects which have been combated since the patient had the opportunity of only a single restorative procedure in each cavitated area. The use of appropriate assessment criteria in individuals of high caries risk adds on to the strengths of the study.

Limitation of the study was its short-term nature; nonetheless, ongoing evaluations of patients will be conducted in the future. Future research with a larger sample size and longer follow-up period is recommended along with comparative evaluation of bioactive composites in other clinically relevant carious areas.

Under the limitations of the study, there was no statistically significant difference seen in the clinical performance of bioactive CR Predicta Bioactive Bulk (PREDICTA, Parkell™) and nonbioactive CR 3M™ Filtek™ Bulk Fill Posterior Restorative (3M, ESPE™) in class V lesions of high-risk caries patients.

CONCLUSION

Predicta Bioactive Bulk and 3M™ Filtek™ Bulk Fill Posterior Restorative demonstrated equivalent effectiveness in the restoration of Class V caries in high-risk caries patients.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.