Modulation of dental caries-associated oxidative stress by different restorative materials: A salivary malondialdehyde-based in vivo study

Abstract

Background:

Dental caries induces a chronic inflammatory response leading to systemic oxidative stress through excessive reactive oxygen species generation. Restorative treatment may modulate this imbalance, with salivary malondialdehyde (MDA) serving as a reliable biomarker of oxidative stress reduction.

Aim:

The aim is to evaluate the effect of Cention N and nano composite restorative materials on caries-induced systemic oxidative stress, assessed through reactive oxygen species (ROS) modulation using salivary MDA as a biomarker.

Subjects and Methods:

Sixty patients with dental caries in a single tooth not involving the pulp were selected for the study. Informed consent and institutional ethical approval were obtained for the same. The individuals were divided into two groups based on the type of restorative material planned for them, i.e., Cention N and Nano composite. Five milliliter saliva samples were collected before as well as 24 h, 7 days, and 14 days postrestoration. The salivary oxidative stress (OS) was assessed at all-time points using salivary MDA as a biomarker, and the findings were statistically analyzed.

Statistical Analysis:

Data were analyzed using SPSS 30.0 version software using Kolmogorov–Smirnov test, followed by Mann–Whitney U test and the Friedman test.

Results:

At all three postrestoration time points, Cention N produced a more pronounced reduction in oxidative stress marker levels when compared to the nanohybrid composite, indicating superior antioxidative potential.

Conclusion:

It may, therefore, be concluded that Cention N restorative material results in rapid and superior reduction of caries-induced inflammatory stress in the body as compared to nano-composite restorative material.

INTRODUCTION

Dental caries, recognized as a localized infectious disease, has increasingly been associated with systemic biological responses, particularly oxidative stress. The cariogenic process involves chronic inflammation induced by the formation of biofilm and the activity of acidogenic bacteria such as Streptococcus mutans. These bacteria not only demineralize enamel through acid production but also trigger inflammatory responses in the host.[1]

Dental caries-induced oxidative stress, denoted by elevated reactive oxygen species, may be modulated by reliable treatment modalities, with salivary malondialdehyde (MDA) levels serving as one of the biomarkers for estimating the stress response.[2] Biomarkers are measurable indicators of biological processes, pathogenic conditions, or pharmacological responses to therapeutic interventions, which can be detected in various biological samples such as blood, saliva, urine, or tissue. These are widely used in clinical and research settings for diagnosis, prognosis, and monitoring of disease progression or treatment efficacy. They provide critical insights into underlying biochemical and molecular changes, often before clinical symptoms become apparent, thereby reflecting the inflammatory status, oxidative stress, tissue destruction, or microbial activity.[3]

The inflammation and bacterial activity with carious lesions associated with amplified reactive oxygen species generation can compromise the healing environment, thereby impairing the bonding efficacy of restorative materials.[4]

In contemporary practice, carious teeth are restored using tooth-colored restorative materials, which have gained widespread popularity and acceptance owing to the evolution in properties such as improved strength, biocompatibility, sealing ability, and esthetics.

A nano composite restorative material is designed for versatile dental restorations, which utilizes true nanotechnology, offering excellent polish retention, strength, and esthetics.[5]

Cention N, on the other hand, was introduced by Ivoclar Vivadent (Schaan, Liechtenstein) in 2016. As an esthetic biomimetic restorative material with high flexural strength. It is a member of the alkasite group and has alkaline fillers, capable of releasing acid-neutralizing ions.[5]

There exists a significant lacuna in the current body of knowledge relating to the comparative modulatory impact of contemporary esthetic restorative materials, Cention N, and nano composite, on systemic oxidative stress induced by dental caries. This study aims to address this knowledge gap by comparing the ameliorating effects of these modern restorative materials on systemic oxidative stress, thereby providing an improved understanding of their biocompatibility, safety, and therapeutic potential.

SUBJECTS AND METHODS

Ethical approval and clearance for this in vivo study were obtained from the Institutional Ethical Committee, [Ref no: IIDS/IEC/2025/Endo/117(xviii)], following the guidelines proposed by the World Medical Declaration of Helsinki. A detailed case history and informed written consent were obtained from all patients prior to inclusion. A total of 60 patients, aged between 15 and 40 years, free from any systemic diseases, who reported to the Department of Conservative Dentistry and Endodontics were examined and included in the study. The sample size was determined using G Power software 3.1. Patients with multiple carious tooth surfaces and restorations, those currently undergoing antibiotic or analgesic therapy within the past 2 weeks, and individuals with any systemic conditions or habits were excluded from the study.

Clinical examination was conducted on all the surfaces of the carious tooth using the visual method under magnification (Labomed) (×3.5) and the tactile method by light probing using No. 23 explorer. To evaluate the lesion activity, two parameters were checked: lesion color and tactile properties. An active lesion was identified as yellowish or light brownish in color with a dull appearance, smooth and leathery consistency with ill-defined margins. Inactive lesions were designated as those which yellowish, brownish, or black in color with a shiny appearance, hard on light probing, with smooth margins. Caries excavation and cavity preparation were followed by restoration with the designated 3M ESPE Filtek supreme Flowable restorative. Where 30 cavities in 30 patients were restored with Ivoclar vivadent [Group 1], and the other 30 cavities in 30 other patients were restored using flowable nano composite [Group 2].

About 5 ml of saliva was collected and stored from each participant at four different time points, i.e., before restoration and 24 h, 7 days, and 14 days post restoration. The saliva was centrifuged at 3000 rpm for 15 min in a centrifuge machine (REMI), the clear supernatant was separated from it and stored frozen at − 20°C until assayed.

Using the Thiobarbituric Acid Reactive Substances Assay, 0.5 ml each of the saliva sample, 2.5 ml of 20% trichloroacetic acid, and 1 ml of thiobarbituric acid were added and mixed well. The mixture was then boiled in a hot water bath for 30 min. After cooling in cold water, the resultant chromogen was extracted with 4 ml of n-butyl alcohol, and the organic phase was separated, which was centrifuged at 3000 rpm for 10 min. Absorbance of the butyl alcohol extracts of standards, as well as test samples were measured at 530 nm against distilled water as a blank. The standard curve was plotted, and the concentration of total MDA in samples was calculated and expressed as MDA in nmol/ml from the curve.

Statistical analysis

Data were entered into the Excel sheet and analysed using SPSS (Statistical Package for Social Sciences) 30.0 version. Data were analyzed for probability distribution using the Kolmogorov–Smirnov test and were not found to have normal distribution. Thus, nonparametric tests of significance were applied. Inter-group comparison was made using the Mann–Whitney U test, and intra-group comparison was made using the Friedman test. P <0.001 was considered statistically significant.

RESULTS

Both groups demonstrated compared values of MDA at baseline, i.e., T0, within 24 h of treatment, and both materials presented significantly lowered MDA levels with, Cention-N presenting a statistically significant reduction compared to Nano Composite. This trend continued at 7- and 14-day posttreatment with the most substantial and sustained reduction of reactive oxygen species observed within the first 7 days of restoration in the Cention-N, as shown in Table 1.

Table 1.

Intergroup comparison of malondialdehyde concentration between Group 1 and Group 2

Group	T0		T1		T2		T3
	Median (IQR)	Mean rank	Median (IQR)	Mean rank	Median (IQR)	Mean rank	Median (IQR)	Mean rank
Group 1	4.64 (4.62–4.65)	33.18	3.85 (3.85–3.95)	15.50	3.22 (3.12–3.22)	15.50	2.41 (2.31–2.51)	15.50
Group 2	4.63 (4.620–4.640)	22.82	4.18 (4.16–4.22)	45.50	3.375 (3.36–3.38)	45.50	2.665 (2.6575–2.6800)	45.50
Z	−1.296		−6.773		−6.805		−6.756
P	0.195		<0.001*		<0.001*		<0.001*

*Statistically significant. Mann–Whitney U-test. IQR: Interquartile range

At baseline (T0), the median values were comparable between Group 1 and Group 2. The mean ranks (33.18 for Group 1 and 22.82 for Group 2) and the Z-value indicated no statistically significant difference between the groups at T0.

Overall, while both groups showed a progressive reduction in median values from T0 to T3, Group 2 consistently exhibited significantly higher values than Group 1 at all postbaseline time points (T1–T3). This indicates a statistically significant intergroup difference favoring Group 1 during the follow-up period.

Overall, both groups exhibited a statistically significant and consistent decline in median values from baseline to T3, demonstrating that the measured parameter changed significantly over time within each group.

In Group 1, the median score showed a progressive decrease from T1 to T3. Similarly, Group 2 demonstrated a consistent reduction in median scores from T1 to T3, with mean ranks decreasing from 4.00 at T1 to 1.00 at T3, as shown in Table 2.

Table 2.

Intra-group comparison of malondialdehyde concentration between Group 1 and Group 2

Group	T0		T1		T2		T3		χ2	P-rf
	Median (IQR)	Mean rank	Median (IQR)	Mean rank	Median (IQR)	Mean rank	Median (IQR)	Mean rank
Group 1	4.64 (4.62–4.65)	4.00	3.85 (3.85–3.95)	3.00	3.22 (3.12–3.22)	2.00	2.41 (2.31–2.51)	1.00	90.000	<0.001*
Group 2	4.63 (4.620–4.640)	4.00	4.18 (4.16–4.22)	3.00	3.375 (3.36–3.38)	2.00	2.665 (2.6575–2.6800)	1.00	90.000	<0.001*

*Statistically significant. Friedman test. IQR: Interquartile range

The analysis demonstrated that both restorative materials produced a significant, time-dependent reduction in salivary MDA levels following treatment. However, Group-1 (Cention-N) showed a more pronounced and consistent decrease in oxidative stress when compared with Group-2 (Nano composite). This sustained reduction suggests a superior bioactive potential of Cention-N, with a greater capacity to modulate the inflammatory response and restore oxidative balance in the oral environment, as shown in box plots in Figures 1 and 2.

Figure 1.

Box plot showing malondialdehyde concentration in Cention N (Group 1)

Figure 2.

Box plot showing malondialdehyde concentration in nano composite (Group 2)

DISCUSSION

Dental caries involves an inflammatory cascade, where immune cells generate reactive oxygen species (ROS) to combat microbial invasion. Excessive ROS generation can surpass the antioxidant defence capacity, leading to oxidative stress, which contributes to damage of carbohydrates, lipids, proteins, nucleotides, and DNA both locally (in oral tissues) and systemically.[6]

Reactive free radicals are able to damage cells by initiating lipid peroxidation, causing major changes in the structural integrity and function of cell membranes. When these free radicals react with lipids, the reaction is termed lipid peroxidation, producing MDA as a by-product.[7] Elevated salivary MDA levels have been reported in patients with untreated dental caries, suggesting that dental infections may contribute to systemic oxidative imbalance, as stated by Subramanyam et al.[8] Skutnik-Radziszewska et al. demonstrated that children with active caries exhibit significantly higher salivary MDA levels when compared to caries-free controls, indicating MDA’s sensitivity as a biomarker for caries-related oxidative stress.[9]

Literature reveals that the effective restorative treatment has the potential to reduce the inflammatory burden and associated oxidative stress, which is reflected in a measurable decrease in salivary MDA levels.

The present study provides compelling evidence that restorative treatment of dental caries using contemporary restorative materials – bioactive Cention-N and nanocomposite – significantly reduces systemic oxidative stress, as demonstrated by the progressive decline in salivary MDA levels following therapeutic intervention. The observed reduction in MDA levels across both treatment groups supports the hypothesis that caries removal and subsequent restoration alleviate the chronic oxidative burden caused by carious lesions. This phenomenon likely stems from the elimination of bacterial biofilms and inflammatory mediators that drive ROS production.[10]

In this study, the most pronounced MDA reduction occurred within the first 7 days posttreatment, suggesting this period represents a critical window for inflammatory resolution and redox balance restoration. This rapid response may be attributed to the immediate removal of caries-related pro-oxidant stimuli and the subsequent healing of surrounding dental tissues.

Cention-N was observed to demonstrate accelerated attenuation in oxidative stress compared to the composite at all evaluated time points. This enhanced performance may be explained by several unique material properties, such as its alkaline pH, which creates unfavourable conditions for residual bacterial survival, sustained fluoride and calcium ion release that may directly scavenge ROS and promote remineralization, and the potential antioxidant effects of its bioactive components.[10] Aliakbarpour et al. also highlighted the importance of early MDA reduction posttreatment, suggesting that reduced lipid peroxidation is a dynamic indicator of tissue recovery following restorative therapy.[11]

The gradual stabilization of MDA levels between day 7 and day 14 in both groups suggests that oxidative homeostasis is reestablished within 2 weeks of treatment. However, the persistently lower MDA values in the Cention-N group at 14 days indicate that this material may offer longer-term benefits in maintaining redox balance. This finding has particular clinical relevance for patients with multiple carious lesions or systemic conditions associated with oxidative stress, such as diabetes or cardiovascular diseases.[12]

Cention-N’s bioactive properties potentially modulate inflammatory response more effectively than conventional composites, thereby reducing ROS generation at the tissue level. In addition, its ion release capacity may directly neutralize existing oxidative species and inhibit ROS-producing enzymes.[13]

Certain limitations must, however, be acknowledged, which include the fact that the 14-day observation period, while sufficient to demonstrate initial trends, may not capture long-term oxidative status changes. In addition, while MDA is a well-established oxidative stress marker, incorporating complementary biomarkers (e.g., 8-hydroxydeoxyguanosine for DNA oxidation or antioxidant enzyme activities) could provide a more comprehensive assessment in future studies.[14,15]

CONCLUSION

Within the limitations of the present study, it may be concluded that successful removal of carious tissue and restoration with Cention-N and materials like nanofilled composite result in accelerated modulation of oxidative stress, indicating that restorative treatment effectively mitigates the inflammatory and oxidative burden imposed by active carious lesions.

While both materials are effective, Cention-N may be the preferred restorative choice in clinical situations where minimizing oxidative stress is desirable – particularly in patients with multiple lesions, compromised immune function, or systemic conditions where oxidative stress plays a contributory role.

Future research should incorporate longer follow-up periods, larger sample sizes, and additional oxidative biomarkers to provide a more comprehensive understanding of the biological responses elicited by contemporary restorative materials.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.