Comparative Assessment of Tooth Discoloration Following Premixed Calcium Silicate Cement Application with Various Surface Treatments: An In Vitro Study

Abstract

In this in vitro study, we compare the discoloration potential of three premixed calcium silicate cements, specifically EndoCem MTA Premixed, Bio-C Repair, and NeoPUTTY, when applied with or without two surface pretreatments (Nd-YAG laser irradiation or dentin-bonding agents). One hundred extracted human maxillary incisors were allocated into ten groups (n = 10), including the untreated control group. A standard access cavity was prepared in all teeth except the control group. Groups were formed according to the type of premixed calcium silicate cement used and the surface pretreatment applied to the internal surfaces of the cavities. Color measurements were taken with a VITA Easyshade Advance 5.0 spectrophotometer and converted to ΔE values using the CIEDE2000 formula at baseline (T0) and 7 (T1), 30 (T2), 90 (T3), and 180 (T4) days. Data were analyzed using the Shapiro–Wilk test to assess normality, followed by the Friedman and Kruskal–Wallis tests for within- and between-group comparisons, respectively (α = 0.05). No statistically or clinically significant differences in ${∆\mathrm{E}}_{00}$ were detected among materials, surface treatments, or timepoints (p > 0.05). All mean ${∆\mathrm{E}}_{00}$ values remained below the perceptibility threshold (3.5). Within the limitations of this 180-day in vitro model, the tested materials showed favorable short-term color stability, and neither the Nd-YAG laser nor the dentin-bonding agents altered the outcomes. Long-term in vivo studies are required to recommend their clinical use in aesthetically critical areas.

1. Introduction

Vital pulp therapy (VPT) is a treatment approach that is intended to protect and heal pulp tissue damaged by extensive caries, dental trauma, restorative procedures, or iatrogenic factors. VPTs are based on the principle of minimally invasive therapy and include procedures such as partial pulpotomy, full pulpotomy, and pulp capping [1,2]. VPTs using appropriate techniques and materials may reduce the progression of dental pulp disease. Given that the pulp-coating material comes into direct contact with the strongly vascularized pulp tissue, it is essential that such materials are biocompatible and non-toxic. Furthermore, because the clinical success of VPT depends on both appearance and tissue preservation, color stability and high biocompatibility should be considered integral clinical requirements [1,3].

The evolution of calcium silicate cements (CSCs) has been characterized by substantial modifications, including the incorporation of alternative radiopaque substances and additives. The integration of bio-ceramics within dental procedures has been demonstrated to be particularly effective in the repair of root perforation and VPT. This is due to the former’s advantageous handling characteristics and rapid setting time, which renders them wash resistant upon contact with moisture [4,5].

Recently, a range of premixed putty-type bioactive ceramic cements (PPBCs) have been formulated and commercialized in capsule, syringe, and needle syringe formats [5]. EndoCem MTA Premixed (ECPR) (Maruchi, Wonju, Republic of Korea), NeoPUTTY (NuSmile, Houston, TX, USA), and Bio-C Repair (Angelus, Londrina, Brazil) are examples of new PPBCs [5,6,7]. In a previous study, it was found that although ECPR has a longer setting time than Endocem^® MTA Zr and RetroMTA; however, it is a promising material in that it has improved solubility and compressive strength and can be shortened because of the properties of premixed CSC [8]. NeoPutty is non-staining because it contains a non-staining radiopaque agent known as tantalum oxide, which does not cause tooth discoloration [9]. Bio-C Repair (Angelus, Londrina, Brazil) is another premixed bio-ceramic cement. It has the same properties as white MTA, in addition to cytotoxicity, bioactivity, and biomineralization. It contains zirconium oxide, which acts as a radiopaque agent [7,10,11].

Laser technologies and dentin-bonding agents (DBAs) are increasingly being considered for use in surface pretreatment prior to CSC application. Nd-YAG laser treatment has been shown to occlude dentinal tubules via melting and recrystallization, which reduces dentin permeability and may help prevent the diffusion of discoloring agents [10,11]. Similarly, DBAs have been reported to reduce crown discoloration when applied to dentin surfaces, likely via blocking tubular pathways and preventing blood infiltration [12].

However, the biological implications of such pretreatment methods remain a subject of concern. When DBAs are applied directly onto exposed pulp tissue, they may cause persistent inflammation, impair healing, and hinder dentin bridge formation [13]. The resulting polymer layer could obstruct cellular migration and mineral deposition, ultimately interfering with the regenerative potential of calcium silicate-based materials. In contrast, when DBAs are limited to dentin surfaces without direct pulp contact, they may offer aesthetic benefits by sealing dentinal tubules [14,15,16].

There are aesthetic challenges involved in treating young permanent incisors, especially those with traumatic pulpal injury. Any coronal discoloration will be disturbing during the patient’s developmental years. In such cases, PPBCs have been proposed as pulp-protective materials; yet, only a few studies have examined their coronal color stability, and long-term clinical evidence remains inconclusive. Furthermore, no investigation has yet explored whether dentin surface pretreatments—such as Nd-YAG laser irradiation or the application of a DBA—modify the coronal discoloration behavior of PPBCs [12,17].

Therefore, this study aims to compare the short-term color change potential of three contemporary PPBCs with and without two surface pretreatment protocols to determine suitable options for aesthetically critical young permanent teeth. The null hypothesis of this study is that premixed CSCs and surface treatments, when used in VPT, will not cause coronal tooth discoloration.

2. Materials and Methods

2.1. Sample Selection

The present laboratory study was conducted in accordance with the Preferred Reporting Items for Laboratory Studies in Endodontology (PRILE) 2021 guidelines (Figure 1) [18]. The research plan was approved by the Ethics Committee of Ordu University (Ethics No. 2024/49). Informed consent was obtained from all study participants. The statistical power analysis was conducted using G-Power (Version 3.1.9.7, University of Düsseldorf, Düsseldorf, Germany), with consideration being given to the findings of a recent study with a comparable design that was documented in the literature [19]. The alpha error rate was set at 0.05, and the power was set at 80%, with an effect size of 0.25. The results of the power analysis indicated that ten teeth were required for each group, yielding a total of 100 extracted human teeth.

2.2. Tooth Preparation

This study involved the use of 100 human maxillary central and lateral incisors that had been freshly extracted and were free from caries, resorption, and developmental defects. The specimens were sterilized with 0.5% chloramine-T solution (Merck, Darmstadt, Germany) for 48 h. The specimens were meticulously cleaned using an ultrasonic scaler (WOODPECKER^® Cavitron, Guilin Woodpecker Medical Ins. Co., Guilin, China) to ensure the removal of soft tissue debris, tartar, and external stains. Following this procedure, the specimens were then polished with a pumice stone and water to achieve a smooth, polished surface.

For each specimen, a standard access cavity was prepared from the lingual surface, without removing the roof chamber, using a cylindrical diamond bur, building a cavity with a width of approximately 3 mm and a depth of 3 mm. The enamel–dentin thickness on the buccal surfaces of the crowns was measured using a digital caliper (Mitutoyo 547-500S, Mitutoyo Corp., Kawasaki, Japan) to be between 2 and 2.5 mm for each sample. Following preparation, all samples were irrigated with 1% sodium hypochlorite for 1 min and then with 17% EDTA solution for 1 min to remove the smear layer. The final rinse solution used was 5 mL of distilled water. The teeth were stored in distilled water at an ambient temperature until the material was applied.

2.3. Experimental Design

According to the surface treatment and the CSCs to be used, the study groups were designed as follows. Material compositions and application methods are presented in

Table 1. Material compositions and application methods.

Materials	Manufacturer	Chemical Composition	Application Steps as Recommended by the Manufacturer
Nd-YAG Laser	Smart file, Deka Laser Technologies, Firenze, Italy	N/A	The laser parameters were set to 1 W/cm2 power, 10 Hz frequency, and 100 mJ/cm2 energy density. The dentin surface was exposed to a pulsed beam at 10 Hz and 1 W for a total of 60 s to simulate clinical manipulation.
Clearfil™ Tri-S Bond Universal	Kuraray Noritake Dental Inc., Niigata, Japan	Bis-GMA, HEMA, ethanol,10-MDP, hydrophilic aliphatic dimethacrylate, colloidal silica, camphoroquinone, silane coating agent, accelerator, initiators, and water.	Universal adhesive system (SE technique) 1. Apply adhesive for 20 s 2. Gentle air stream 5 s 3. Light-polymerize 10 s
Endocem MTA Premixed	Maruchi, Wonju, Republic of Korea Serial number: M1240518 exp date: May 2026	Tricalcium silicate, calcium aluminate, calcium sulfate, dimethyl sulfoxide, thickening agents (lithium carbonate, hydroxypropyl methylcellulose, phyllosilicate mineral), and zirconium dioxide.	Setting time: Initial: 7 min The material should be applied with a thickness of at least 3 mm. After application, a sterile, moist cotton pellet should be placed on it for 3 min, and then the material should be gently pressed with moist cotton.
Bio-C Repair	Angelus, Londrina, PR, Brazil Serial number: 74055 exp date: May 2026	Calcium silicate, calcium aluminate, calcium oxide, zirconium oxide, silicon oxide, polyethylene glycol, and iron oxide.	Setting time: ≤120 min Place a lightly moistened sterile cotton ball over BIO-C® REPAIR and wait 15 min for the material’s initial setting.
NeoPutty	NuSmile, Houston, TX, USA Lot: 2023 102607 Exp date: September 2026	Tantalite, tricalcium silicate, calcium aluminate, dicalcium silicate, tricalcium aluminate, calcium sulfate, proprietary organic liquid, and stabilizers.	Applying a minimum thickness of 1.5 mm Setting time: ~4 h.

.

2.3.1. Nd-YAG Laser

The laser parameters were set at 1 W/cm² power, 10 Hz frequency, and 100 mJ/cm² energy density, which was in accordance with the manufacturer’s instructions. To simulate clinical conditions, the dentin surface was exposed to a pulsed beam at 10 Hz and 1 W for a total duration of 60 s. The procedure was performed using an uncooled handpiece with a 300 μm optical fiber operating with a pulse duration of 50 μs throughout the entire exposure period. The laser beam was directed perpendicularly to the dentin surface, with a distance of 1 mm being maintained between the beam and the surface. Each 1 mm² area was irradiated for 1 s to ensure uniform application [17,20].

2.3.2. Dentin Bonding Agent

The inner dentin surfaces of the cavity were treated with two layers of dentin bonding agent (CLEARFIL™ TRI-S BOND Universal; Kuraray Noritake Dental Inc., Japan) according to the manufacturer’s instructions. This involved applying the agent with a micro-applicator (20 s), followed by air drying for 5 s and curing at 385–515 nm for 10 s using PayWave light-emitting diodes (LEDs; Valo Cordless, Ultra dent, South Jordan, UT, USA) [21].

The samples were then randomized (Random.org) and divided into ten groups (n = 10) as follows (

Table 2. Study groups.

Groups (n = 10)	Materials	Surface Pretreatments
G0	No	No
G1	EndoCem MTA Premixed	No
G2	Bio-C Repair	No
G3	NeoPUTTY	No
G4	EndoCem MTA Premixed	Dentin-Bonding Agents
G5	Bio-C Repair	Dentin-Bonding Agents
G6	NeoPUTTY	Dentin-Bonding Agents
G7	EndoCem MTA Premixed	Nd-YAG Laser
G8	Bio-C Repair	Nd-YAG Laser
G9	NeoPUTTY	Nd-YAG Laser

):

Group 0 (G0) served as the negative control, with cavities left empty and receiving no treatment. In the remaining groups, standardized access cavities were prepared and filled with one of three premixed calcium silicate cements—EndoCem MTA Premixed, Bio-C Repair, or NeoPUTTY—either without surface pretreatment, following Nd-YAG laser irradiation, or after the application of a dentin bonding agent (DBA) to the internal surfaces of the cavities.

Following the surface treatment of the tooth’s dentin wall, a 2 mm thick calcium silicate cement was placed in the cavity. The restoration was then finished with resin-modified glass ionomer cement (RMGIC; Riva Light Cure, SDI, Bayswater, VIC, Australia) after the hardening reaction of each material had been completed, in accordance with the manufacturer’s instructions. The RMGIC was cured at 385–515 nm for 20 s using PayWave LEDs (Valo Cordless, Ultradent, South Jordan, UT, USA). Each specimen was stored in a separate tube filled with distilled water and stored in the dark at room temperature. The distilled water was replaced after a period of 10 days.

2.4. Tooth Color Assessment

The initial shade values were measured using a spectrophotometer, a device that measures light absorption and is used to determine the color of a substance (VITA Easy Shade Advance 5.0, VITA Zahn fabric, Bad Säkingen, Germany). After the color measurements, the L*a*b* coordinates were recorded, and the mean values were estimated. The teeth were distributed into ten groups (n = 10) according to their colorimetric data to avoid significant variations between samples in the same experimental group. Subsequently, each tooth was measured three times by the same operator, who was blinded to group allocation to ensure procedural consistency (N.K.S.) and thus enhance reliability and minimize intra-operator variability. The experimental groups were formed with a balanced distribution of teeth having the same colorimetric references (e.g., in the same experimental group, there were three teeth colored A2, three teeth colored B1, two teeth colored B2, and two teeth colored A3) [20]. The color evaluation was conducted using CIE Lab* color space parameters. The lightness of an object is indicated by the L* coordinate, which scales from white (0) to absolute black (100). The a* coordinate signifies the chromaticity on a green (−) to red (+) axis, with values typically ranging from −70 for green to +70 for red. The b* coordinate measures chromaticity on a blue (−) to yellow (+) axis, on which values range from −80, indicating blue, up to +100, signifying yellow. The teeth were placed on a white background (a standard calibration tile following the Commission Internationale de l’Éclairage [CIE; L*: 93.84, a*: −1.48, and b*: 3.76], and the tip of the spectrophotometer was carefully positioned to be in full contact with the flattest area of the buccal surface of the tooth, specifically targeting the central region located 2 mm above the cementoenamel junction. The instrument was calibrated according to the manufacturer’s guidelines before initiating measurements for each new experimental group. To ensure the precision of the color analysis, the same tooth samples were also evaluated with a DSLR camera (80D, Canon, Tokyo, Japan) equipped with a macro lens (Canon EF 100 mm; Canon, Tokyo, Japan). Digital photographs of the tooth samples were taken from the buccal aspect of the teeth at the same time intervals under laboratory conditions. A Twinflash (Godox MF12) was used as the light source with a mini-softbox. The flash heads provided daylight-balanced illumination at ≈5600 K, ensuring that each shot would have the same focal length, working distance, and flash power. The CIEDE2000 color space system (Commission Internationale de L’Eclairage, Vienna, Austria) has been used for the recording of color measurements. The change in color ($∆E_{00}$) was assessed by comparing the values obtained before endodontic treatment (baseline; T0) with those measured at (T7) 7, (T30) 30, (T90) 90, and (T180) 180 days. A $∆E_{00}$ value ≥ 3.5 was considered clinically perceptible. The following formula was used to calculate $∆E_{00}$ [22]:

$$∆E_{00}=\sqrt{{\left({\displaystyle \frac{∆L^{\prime }}{k_L{S}_L}}\right)}^2+{\left({\displaystyle \frac{\Delta C^{\prime }}{k_C{S}_C}}\right)}^2+{\left({\displaystyle \frac{\Delta H^{\prime }}{k_H{S}_H}}\right)}^2+R_T\left({\displaystyle \frac{∆C^{\prime }}{k_C{S}_C}}\right)\left({\displaystyle \frac{∆H^{\prime }}{k_H{S}_H}}\right)}$$

where

• ΔL′, ΔC′, and ΔH′ represent the differences in lightness, chroma, and hue, respectively;
• R_T is the rotation function used to explain the interaction between chroma and hue in the blue region;
• S_L, S_C, and S_H are the weighting functions for lightness, chroma, and hue;
• K_L, K_C, and K_H are parametric factors (all set to 1 under standard laboratory conditions.

2.5. Statistical Evaluation

The NCSS (Number Cruncher Statistical System) 2007 Statistical Software Package (v 07.01.08, Kaysville, UT, USA) was used for the statistical analyses performed in this study. In addition to descriptive statistics, the distribution of each variable was analyzed using the Shapiro–Wilk test for normality, the Friedman test to compare variables over time when their distribution was non-normal, and the Kruskal–Wallis test for intergroup comparisons. The results were assessed at a significance level of p < 0.05.

3. Results

Table 3. Mean ± standard deviation (SD) and median (interquartile range, IQR) values of $∆E_{00}$ at different time points (T0, T7, T30, T90, and T180) for each experimental group. p-values are based on the Friedman test within groups (p > 0.05).

		T0–T7	T0–T30	T0–T90	T0–T180	p †
Group 0	Mean ± SD	2.03 ± 1.2	1.6 ± 0.82	2.1 ± 1.18	1.83 ± 1.12	0.323
	Median (IQR)	1.85 (1.04–3.11)	1.63 (0.77–2.21)	1.9 (1.12–3.26)	1.86 (0.89–2.43)
Group 1	Mean ± SD	1.76 ± 0.99	2.14 ± 1.32	1.94 ± 1.13	1.94 ± 0.84	0.668
	Median (IQR)	1.87 (0.67–2.66)	2.61 (0.56–3.25)	1.9 (0.82–2.85)	1.72 (1.24–2.87)
Group 2	Mean ± SD	1.49 ± 1.28	1.88 ± 0.95	1.68 ± 1.01	1.57 ± 1.27	0.668
	Median (IQR)	1.28 (0.39–2.34)	1.43 (1.2–2.82)	1.79 (0.58–2.62)	0.84 (0.72–2.53)
Group 3	Mean ± SD	2.31 ± 0.95	2.54 ± 0.94	2.68 ± 1.18	2.62 ± 0.5	0.976
	Median (IQR)	2.18 (1.62–3.2)	2.62 (1.92–3.33)	2.61 (1.88–3.35)	2.48 (1.91–3.2)
Group 4	Mean ± SD	1.85 ± 0.7	2.38 ± 1.59	2.02 ± 0.81	1.85 ± 1.12	0.668
	Median (IQR)	1.88 (1.35–2.43)	2.21 (0.81–3.32)	2.29 (1.38–2.52)	1.73 (0.89–2.78)
Group 5	Mean ± SD	2.16 ± 1.13	2.59 ± 1.57	1.87 ± 1.09	1.88 ± 0.87	0.356
	Median (IQR)	2.47 (0.83–3.03)	2.19 (1.28–4.32)	1.9 (0.84–2.72)	1.86 (1.26–2.51)
Group 6	Mean ± SD	2.22 ± 1.35	1.78 ± 0.75	2.35 ± 1.28	2.85 ± 1.22	0.566
	Median (IQR)	2.01 (0.94–3.27)	1.67 (1.18–2.38)	2.03 (1.75–2.85)	2.52 (1.81–4.4)
Group 7	Mean ± SD	2.23 ± 0.92	1.77 ± 1.09	1.68 ± 1.08	1.53 ± 0.64	0.430
	Median (IQR)	2.03 (1.64–2.86)	1.48 (1.12–2.21)	1.5 (0.68–2.78)	1.34 (1.01–1.89)
Group 8	Mean ± SD	2.4 ± 1.12	1.74 ± 1.31	2.63 ± 1.26	1.72 ± 0.97	0.101
	Median (IQR)	2.34 (1.47–3.04)	1.59 (0.62–3.16)	2.35 (1.72–3.61)	1.87 (0.65–2.68)
Group 9	Mean ± SD	3.1 ± 1.59	2.63 ± 1.13	2.45 ± 1.58	1.62 ± 1.32	0.062
	Median (IQR)	2.83 (1.72–4.58)	2.56 (1.71–3.25)	1.59 (1.13–4.38)	1.09 (0.64–2.23)
	p ‡	0.352	0.377	0.598	0.073

‡ Kruskal–Wallis Test; † Friedman Test.

presents the ΔE₀₀ values at each time point for all groups, including both mean ± standard deviation (SD) and median with interquartile range (IQR) values to reflect central tendency and distribution spread. All groups exhibited similar trends over time, with no statistically significant difference in $∆E_{00}$ values being observed (p > 0.05). Mean $∆E_{00}$ values at four follow-up intervals (T0–T7, T0–T30, T0–T90, and T0–T180) for all study groups. All mean values remained below the clinically perceptible threshold (ΔE₀₀ = 3.5), with no statistically significant differences over time. Error bars represent standard deviations Figure 2). Throughout this study, no statistically significant differences were observed between the dentin tubule occlusion methods and the calcium silicate cements in terms of tooth discoloration, which was evaluated at baseline (T0) and after 7, 30, 90, and 180 days (p > 0.05). According to the Friedman test, there were no significant changes in color over time in any of the experimental groups (p = 0.323–0.976), indicating stable color performance across all timepoints. Similarly, the Kruskal–Wallis test revealed no significant differences between the various surface treatments and the types of PPBCs used (e.g., T0–T30, p = 0.377). This suggests that neither the material type nor the surface conditioning method had a statistically significant effect on coronal discoloration. Photographs of representative specimens taken at baseline (T0) and after 6 months (T180) are presented in Figure 3.

4. Discussion

Tooth discoloration is an undesirable condition in contemporary dentistry, particularly because of its aesthetic implications. It is also envisaged as unpleasant and, in some cases, psychologically traumatizing [23,24]. Tooth discoloration can occur after traumatic injuries and different dental treatments, and discoloration associated with the biomaterials used in endodontics has been documented in a previous study [25]. Preventive strategies, including the application of DBA and Nd-YAG laser treatment, have been proposed to minimize the diffusion of discoloring agents by sealing dentinal tubules [17,19].

The effect of two dentin surface conditioning methods (Nd-YAG laser and DBA) on the discoloration potential of three PPBCs was evaluated in this in vitro study: ECPR, Bio-C Repair, and NeoPUTTY. None of the PPBCs or surface treatments tested produced a statistically or clinically detectable discoloration ($∆E_{00}$ < 3.5) within the limits of our 180-day in vitro model. Accordingly, the null hypothesis is accepted.

Our study was performed in vitro using freshly extracted human teeth. The distance between the labial surface of the crowns and the cavity floor was standardized in all samples, in line with a previous study [19]. This ensured that color changes could be perceived using teeth of the same thickness. Color measurements were performed using a spectrophotometer, a reliable instrument that has been widely utilized in previous studies [26,27,28]. The spectrophotometer determines color based on the internationally accepted ISO standards using the CIE color model. To assess color change, the ΔE value was calculated, with a threshold of 3.5 being considered a clinically perceptible difference [16,28]. At each time point (T0, T7, T30, T90, and T180), the groups showed no significant difference, and all mean ΔE₀₀ values remained below this threshold value. Therefore, in this 180-day in vitro study, none of the CSCs tested caused clinically significant discoloration. However, longer-term clinical studies with increased sample size are needed.

We used a DSLR camera with a dual flash system and a mini-softbox to take digital photographs of dental specimens. Although the lighting conditions were kept constant during all photo taking, the recent literature has highlighted the importance of the type of light source used regarding accurate shadow assessment. A previous study emphasized that intraoral scanners offer superior accuracy in terms of color registration and that dual-flash systems provide results closer to spectrophotometric values than ring flash systems [29]. Similarly, a recent study reported that the use of polarizing filters, in combination with standardized illumination conditions, improved color-matching accuracy, especially for light tones [30]. These findings suggest that the spectral characteristics of the light source and the use of filters may impact tooth color assessment and should be considered in future research.

Although previous studies have shown that DBAs and laser irradiation can reduce tooth discoloration [17,19], our results suggest that such surface treatments may offer limited additional benefits when using next-generation CSCs. While Nd-YAG lasers are widely used for dentinal tubule occlusion and hypersensitivity management, their presence in our study did not significantly affect the color results.

The effects of adhesive systems on the pulp have long been investigated, and there are many studies showing that these materials can be used as temporary or permanent closure materials [31,32]. In the context of minimally invasive dentistry, the protection of dental tissues and the maintenance of pulpal viability are of great importance. Therefore, adhesive systems should be used carefully and strictly in accordance with the manufacturers’ instructions, especially in procedures performed near the pulp [32]. Universal adhesives can etch enamel and dentin surfaces and penetrate dentinal tubules. This process involves micromechanical anchoring and chemical bonding, increasing the bond strength and durability between the adhesive and tooth structures while reducing the risk of edge leakage [21]. In our study, Clearfil Tri-S Bond Universal was applied to the inner surfaces of dentin using the self-etch method, thus minimizing cytotoxic effects.

Permanent tooth discoloration that occurs because of some materials used in endodontic treatment may require additional bleaching procedures. For this reason, protocols to prevent material-induced tooth discoloration are considered to have an important place in clinical practice. Studies show that DBAs do not completely prevent discoloration but do significantly alleviate it as compared with the control groups with no treatment [12,16]. Although studies have shown that DBAs and laser irradiation can reduce tooth discoloration [17,19], our results suggest that such surface treatments may provide limited additional benefit when PPBCs are used. In addition, Nd-YAG lasers are widely preferred in the treatment of dentin hypersensitivity because of their high efficiency in occluding dentinal tubules and deep penetration capacity, but their presence in our study did not significantly affect the color results.

ECPR is a kind of CSC used in dental applications, especially for VPT and root end filling. It is known for its bioactivity, biocompatibility, and antibacterial properties, making it a popular choice in endodontics. By using the premixed syringe product, convenient clinical user customization and reduced treatment time have been achieved [33]. There are limited studies comparing the discoloration of ECP with DBA application. In this study, the effect of DBA application on the color change caused by triple antibiotic paste (TAP) was investigated. The results show that DBA application is effective in preventing the color change caused by CSCs [34]. Since materials that have already been proven to cause discoloration were not used in our study, it can be said that the effects of surface treatments (DBA and Nd-YAG lasers) on dentinal tubules were less pronounced than in the previous study.

Although coronal discoloration due to CSCs may continue to increase for up to two years, according to the results of previous trials, the minimal discoloration observed in our 180-day in vitro model is consistent with these long-term clinical data [3,35]. The present findings suggest that premixed hydraulic CSCs may support restorative success in aesthetic regions by minimizing tooth discoloration [36].

Recent studies have also reported favorable cytocompatibility for materials such as Bio-C Repair and NeoPUTTY, indicating that these cements provide a dual benefit, preserving optical integrity while supporting pulp–dentin healing [37,38]. However, short periods of laboratory observation cannot accurately mimic intraoral conditions; long-term in vivo studies are still needed. Taken together, the available evidence suggests that premixed cements, such as NeoPUTTY and Bio-C Repair, are promising options for procedures in esthetically critical areas because of their low potential for discoloration.

The main limitations of this study stem from its in vitro design and the 180-day observation period. Important clinical variables, such as pulpal pressure, tissue fluids, salivary enzymes, and oral biofilm formation, were not simulated in the study design. Each of these factors can affect the diffusion of staining agents, the curing behavior of CSCs, and the optical properties of dentin over time. For example, pulpal pressure can alter material–dentin interactions by altering dentin fluid flow, while biofilm metabolites may contribute to extrinsic or intrinsic discoloration. In addition, the spectrophotometric measurements were obtained by the same operator. Although intra-observer reliability is high, the lack of validation among observers limits the generalizability of our findings. Despite the use of a controlled 5500-K LED lighting setup, photographic documentation remains vulnerable to slight deviations in camera distance or angulation as well as to transient enamel dehydration during storage, factors that can artificially lighten the tooth surface and obscure subtle early-stage color changes. Furthermore, the biological effects of surface pretreatments on the material–dentin interface should be further investigated using advanced analytical techniques, such as scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Consequently, although our findings indicate favorable short-term color stability, the clinical applicability of premixed CSCs, especially in aesthetically critical areas, must be confirmed via long-term in vivo studies.

5. Conclusions

In this study, we evaluated the effects of three modern PPBCs (ECPR, Bio-C Repair, and NeoPUTTY), along with two surface treatment modalities (Nd-YAG lasers and DBAs), on coronal tooth discoloration. Our study also highlights the importance of selecting CSCs with an optimized formulation to reduce the risk of complications in aesthetic areas. The findings revealed that none of the tested materials induced statistically significant or clinically perceptible discoloration over a 180-day period. In addition, the surface treatments did not significantly affect the color outcomes, likely due to the inherently low staining potential of the materials. Our study also highlights the importance of selecting CSCs with optimized formulations to reduce the risk of complications in aesthetically important areas. Within the limitations of this in vitro study, the premixed bio-ceramic cements tested exhibited favorable short-term color stability; nonetheless, when considering routine use in aesthetic areas, the findings of long-term in vivo research should be taken into account.

However, this study has certain limitations, including being conducted under in vitro conditions and a limited observation period. Variables such as pulp vitality and oral fluid exposure were not represented under clinical conditions. Therefore, longer-term in vivo studies with increased sample size are needed to evaluate the material–dentin bonding and verify the long-term color stability and clinical performance of these materials in intraoral environments. Our study contributes to the literature by evaluating surface modification and color change together. These two issues have generally been examined separately in the literature; however, evaluating aesthetics and biocompatibility together is very important, especially in young permanent teeth. This approach sheds light on current clinical practices in terms of meeting both functional and aesthetic requirements.