Search Results (653)

Background: Persistent endodontic infections involving Enterococcus faecalis and Candida albicans are a major cause of root canal treatment failure. Although conventional irrigants, such as sodium hypochlorite and chlorhexidine (CHX), exhibit strong immediate antimicrobial activity, microbes may survive and recover from the initial antimicrobial effect, hence limiting their effectiveness, especially in complex root canal anatomies and in the apical terminus of the tooth. Antibacterial dressing techniques were not proven satisfactory due to depletion of the antibacterial component or difficulty in spreading it evenly along the entire root canal. This study aimed to develop and evaluate the antimicrobial efficacy and release characteristics of a novel sustained-release device (SRD), delivering CHX via gutta-percha points coated with a sustained-release formulation used as a temporary intracanal medicament. Methods: Gutta-percha points were coated with two sustained-release CHX varnishes (CHX1 and CHX2) or a placebo and assessed in vitro. Antimicrobial activity against E. faecalis and C. albicans was evaluated using agar diffusion assays over time. Release kinetics were analyzed using Rhodamine-labeled SRD in a 3D-printed acrylic molar tooth model via fluorescence microscopy. Additionally, biofilm-infected acrylic molar teeth were treated with a placebo, a single 2% CHX irrigation, or SRD-coated gutta-percha points placed as an intracanal dressing prior to obturation. Microbial viability was quantified by colony-forming unit (CFU/mL) analysis from root canals and gutta-percha points. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post hoc multiple comparison test (p < 0.05). Results: SRD-coated gutta-percha points demonstrated sustained antimicrobial activity for up to 21 days against E. faecalis and 19 days against C. albicans. Fluorescence analysis, in an acrylic tooth model, confirmed continuous release for up to 15 days, with pronounced diffusion in the isthmus and palatal canals. In biofilm-infected acrylic teeth models, SRD treatment resulted in a significant reduction of 2–3 log₁₀ CFU/mL compared to placebo groups (p < 0.001) and prevented microbial rebound over the 14-day observation period. In contrast, a single application of 2% CHX solution showed only transient reduction followed by regrowth. Conclusions: Sustained-release CHX delivery via polymer-coated gutta-percha points provided prolonged antimicrobial activity against bacterial and fungal biofilms compared to conventional single-dose CHX application in this in vitro model. These findings support the potential use of coated gutta-percha points as a removable intracanal drug delivery platform prior to final obturation, although further studies incorporating direct-release quantification and in vivo validation are required before clinical translation. Full article

Background/Objectives: Despite advances in preventive dental care, tooth enamel erosion remains a relevant concern, and very few comparisons of surface topography have been carried out under controlled conditions in the laboratory. This study primarily aimed to conduct a qualitative morphological evaluation, supported by semi-quantitative image analysis, of the effects of commonly consumed beverages on human enamel morphology and colour, and to explore their relationship with beverage acidity in an in vitro model. Methods: Forty-two human teeth were allocated at random into seven different groups, each containing six molars. These groups were Coca-Cola, orange juice, lemon juice, coffee, chlorhexidine, regular mouthwash without chlorhexidine, and one control group. Following a 24 h exposure to a simulated saliva environment at 37 °C, the test samples were then subjected to a five-day erosion cycle. SEM analysis was used to examine the enamel alterations after evaluating the morphology of the enamel surface and by digital image analysis. Results: Scanning electron microscopy, SEM, showed how erosion of the teeth’s surface increased with the acidity of the drink. The extensive exposure of the crystal prisms, along with the severe loss of intercrystalline material and honeycomb weathering patterns, was all brought about by Coca-Cola and lemon juice. The moderate erosion brought on by orange juice in tests resulted in partially exposed prisms. Both the mouthwashes and the coffee exhibited similar impacts on the tooth enamel in a microscopic view. Minimal enamel prism rods were exposed due to either the coffee or the mouthwash. The surface characteristics were found through a digital image analysis, which indicated alterations in surface texture. Conclusions: Under these immersion conditions, highly acidic beverages produced the most pronounced enamel surface changes, whereas coffee induced mainly staining and neutral mouthwashes caused minimal modification. These results reflect qualitative morphological trends and should not be interpreted as clinical outcomes. Full article

Background: Cavity disinfection is commonly performed in pediatric restorative dentistry to reduce residual bacterial contamination. Although boric acid has been proposed as a potential antimicrobial agent, its effect on marginal integrity and adhesive performance in primary teeth remains unclear. This study evaluated the effects of 3% and 5% boric acid, compared with 2% chlorhexidine (CHX), on microleakage and microshear bond strength of composite restorations in primary teeth bonded with a two-step self-etch adhesive system. Methods: Seventy-two extracted primary second molars were allocated to four groups (n = 18) for microleakage assessment: control, 2% CHX, 3% boric acid, and 5% boric acid. Standardized Class V cavities were prepared, disinfectants were applied for 60 s, and restorations were completed using Clearfil SE Bond and resin composite. Microleakage at occlusal and gingival margins was evaluated using dye penetration. For microshear bond strength testing, 60 primary molars (n = 15 per group) were treated similarly, and shear force was applied to bonded composite microcylinders. Data were analyzed at the p < 0.05 significance level. Results: Both boric acid groups showed significantly higher occlusal and gingival microleakage than the control and CHX groups (p < 0.05). Gingival microleakage was greater than occlusal microleakage in the boric acid groups (p < 0.05). Microshear bond strength was significantly reduced in the boric acid groups compared with the control (p < 0.05), whereas CHX had no significant effect. Failure modes did not differ significantly. Conclusions: While 2% CHX did not adversely affect adhesive performance, 3% and 5% boric acid increased microleakage and reduced bond strength. Caution is advised when using boric acid with self-etch adhesive systems in primary teeth. Full article

Background and Objectives: The use of St. John’s wort (Hypericum perforatum) in periodontal therapy remains underexplored despite its anti-inflammatory, antimicrobial, and potential osteoregenerative effects. This was the first study aiming to determine the in vitro efficacy of ultrasonic debridement combined with a H. perforatum extract against dental biofilms. Materials and Methods: A multispecies biofilm model comprising Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum, and Tannerella forsythia was established on bovine dentin discs. Biofilms were treated with saline solution (control), ultrasonic debridement alone, ultrasonic debridement combined with H. perforatum extract (0.5%), and ultrasonic debridement combined with chlorhexidine (0.12%). Biofilm biomass was quantified with the crystal violet assay, and total viable counts were determined by colony-forming unit (CFU) analysis. Quantitative PCR was used to assess the genomic load of P. gingivalis. Biofilm architecture and bacterial viability were further examined using confocal laser scanning microscopy (CLSM). Results: Ultrasonic debridement combined with H. perforatum extract significantly reduced biofilm biomass compared to saline irrigation (p < 0.001) and ultrasonic debridement alone (p < 0.01). Similar reductions were observed for viable bacterial counts and P. gingivalis genomic load. The antimicrobial effect of the plant extract was comparable to that of chlorhexidine, with only minor differences in efficacy. Confocal microscopy confirmed marked disruption of biofilm architecture and decreased bacterial viability following treatment with the plant extract. Conclusions: Within the limitations of this in vitro model, H. perforatum extract demonstrated measurable antibiofilm activity when used as an adjunct to ultrasonic debridement. These findings provide proof-of-concept evidence supporting the antimicrobial potential of this plant-derived extract under controlled laboratory conditions. Further preclinical studies and well-designed clinical investigations are required to determine its therapeutic relevance in periodontal treatment. Full article

Background: Persistent endodontic infections remain a significant challenge in root canal therapy, primarily due to the complexity of root canal anatomy and the formation of resistant microbial biofilms. Conventional irrigants, including sodium hypochlorite and chlorhexidine, show limited penetration into dentinal tubules and reduced efficacy against mature biofilms, contributing to treatment failure. Electrically charged lipid nanoparticles (ECLNs), such as cationic solid lipid nanoparticles, nanostructured lipid carriers, and liposomes, have emerged as potential adjunctive systems to enhance intracanal antimicrobial delivery. This focused narrative review, informed by a structured literature search, aimed to synthesize and critically evaluate preclinical and exploratory clinical evidence regarding the use of electrically charged lipid nanoparticles for antibiotic delivery and biofilm control in root canal disinfection. Methods: A structured literature search of PubMed, Scopus, and Web of Science (2010–2026) identified 312 records, of which 20 studies met the inclusion criteria and were included in qualitative synthesis. The majority of included studies were in vitro investigations, followed by ex vivo studies using extracted human teeth, with only a limited number of exploratory animal or clinical studies. Overall, the level of evidence was predominantly preclinical. Results: Across studies, ECLNs demonstrated enhanced antimicrobial efficacy compared with free antibiotics or non-charged formulations, with improved biofilm interaction, enhanced penetration into dentinal tubules, and sustained antimicrobial release. However, most investigations relied on mono-species Enterococcus faecalis biofilm models, and substantial heterogeneity in nanoparticle formulation and methodology was observed. Clinical evidence remains scarce. Conclusions: Although these findings about ECLNs suggest a promising experimental adjunct for root canal disinfection, current evidence remains largely preclinical and insufficient to support routine clinical application. Standardized formulations, clinically relevant multispecies biofilm models, and well-designed controlled clinical trials are required to establish safety, efficacy, and translational feasibility. Full article

Background: Oral health (OH) is integral to general health, well-being, and quality of life; however, in long-term care (LTC) settings, it is often neglected due to residents’ functional limitations, high care dependency, and the prioritization of underlying medical conditions by healthcare staff. Previous studies have highlighted this issue and identified multiple barriers to OH promotion in institutional settings. Objectives: To assess OH practices among nurses (NUR) and nursing assistants (NA) in LTC units and to identify barriers compromising effective oral care delivery. Methods: An observational, cross-sectional, descriptive study was conducted across five LTC facilities in Porto, Portugal. A structured survey was administered to 145 healthcare workers out of a total of 259 eligible participants, yielding a response rate of 55.98%. Data were collected via Google Forms and analyzed using IBM SPSS Statistics v.26. Descriptive statistics, analysis of variance, the Mann–Whitney U test, and Chi-square tests were applied, with a significance level of 0.05. Results: The main primary barriers to OH promotion included poor patient cooperation (74.6%), lack of dentists (74.6%), insufficient material (62.7%), limited time (45.8%) and inadequate staffing (40.7%). Chlorhexidine (94.50%) and oral sponges (70%) were the most frequently used resources, whereas other methods were underutilized. No statistically significant differences were observed between professional groups, irrespective of prior training. Although 48.5% of NUR and 51.5% of NA reported not perceiving barriers, substantial gaps in practice were identified. Only 1.9% of untrained NA reported consulting evidence-based scientific sources, compared with 44.7% of untrained NUR. Conclusions: Despite limited perceived barriers, significant deficiencies in OH practices persist in LTC settings, highlighting the need for structured, interdisciplinary training programs to improve oral care delivery. Full article

To evaluate the potential ototoxic effects of lactoferrin on the inner ear using electrophysiological and histological methods. Methods: Thirty-two Sprague-Dawley rats (64 ears) were divided into four groups: control, saline, antiseptic solution (70% isopropyl alcohol + 2% chlorhexidine), and lactoferrin. Groups II–IV received three intratympanic injections. Auditory brainstem response (ABR) tests were performed at baseline, day 7, and day 21. Cochlear histology and VEGF immunoreactivity were assessed. Results: Baseline hearing was similar across groups. Post-treatment, Groups II and IV showed partial recovery at 8, 16, and 24 kHz, while Groups III and IV had worsening thresholds at higher frequencies. Histologically, Group IV’s cochlear structures remained largely intact. VEGF immunoreactivity was severe to moderate in Groups I, II, and IV, and weaker in Group III. Conclusions: Lactoferrin showed relative safety at lower frequencies but possible ototoxicity at higher frequencies. However, no significant structural damage was observed in cochlear tissues. Full article

This study aimed to investigate the effect of time and different disinfecting agents on nanocomposite filler composed of natural clay nanoparticles (modified and non-modified) added to maxillofacial silicone elastomers and readymade pigment additives. A total of 360 disk-shaped samples were divided into nine pigment-based groups, each with four subgroups (n = 10) exposed to different disinfectants: distilled water, 1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and effervescent tablets. Color changes (ΔE) were measured before and after disinfection using a colorimeter. The ΔE values were assessed against perceptibility (ΔE = 1.1) and acceptability (ΔE = 3) thresholds. Nanoclay additives were also characterized using FTIR, XRD and EDX. Statistical analysis, including ANOVA and post hoc HSD tests, revealed that while all samples exhibited some color change, most remained below the acceptability threshold. Colorless silicone showed minimal, non-significant change according to perceptibility threshold (ΔE = 1.1). Blue pigments displayed significant change only with effervescent tablets. Red and mixed pigments showed perceptible changes with NaOCl, CHX, and effervescent tablets. However, nanoclay-containing specimens showed no significant perceptible alterations. Overall, despite minor perceptible changes in some pigments, all disinfecting agents tested resulted in color differences below the acceptability threshold, indicating their safe use for disinfecting maxillofacial silicone materials without compromising esthetics. Nevertheless, nanoclays are more reliable agents for the pigmentation of maxillofacial silicone as they show non-significant chromatic alteration. Full article

Objective: This systematic review aimed to evaluate material-based modifications of resorbable root canal filling materials for primary teeth, assessing how compositional changes—including bioactive additives, antimicrobial agents, and alternative base matrices—influence antimicrobial performance. Methods: A systematic search of PubMed, Scopus, Web of Science (WoS), and Embase was performed in October 2025. Search terms included (primary teeth OR deciduous teeth) AND (root canal filling materials OR root canal filling OR canal obturation) AND (antibacterial agents OR antibacterial OR antimicrobial). Study selection adhered to PRISMA 2020 standards and was systematically organized through the PICO framework. From 199 identified records, 18 studies met the eligibility criteria. Results: Most studies evaluated modified zinc oxide-based materials. Additives such as propolis, Morinda citrifolia extract, Aloe vera, and olive oil enhanced antimicrobial activity or improved clinical and radiographic outcomes compared with conventional zinc oxide–eugenol. Triclosan-containing formulations consistently demonstrated strong antibacterial effects. In contrast, chlorhexidine yielded variable results, with some calcium hydroxide–based pastes showing superior performance in its absence. Antibiotic-enriched materials exhibited high antimicrobial efficacy; however, several studies raised concerns regarding the potential development of bacterial resistance. Conclusions: Most of the introduced modifications of resorbable root canal filling materials for primary teeth enhance antimicrobial activity and their physicochemical properties in vitro. Clinical evidence is limited and heterogeneous, and therefore, its superiority over conventional materials cannot be definitively determined. Further long-term, randomized clinical trials on large patient groups, evaluating the same modifications, are needed to confirm the effects observed in laboratory studies. Full article

Background/Objectives: Chlorhexidine (CHX) and alcoholic (A+) mouthwashes are associated with adverse oral effects. Therefore, this study compared the efficacies of non-alcoholic mouthwashes, including fluoride (A−) and herbal (Hr) rinses, for preventing bacterial accumulation and enamel demineralization around metal brackets (MBs), ceramic brackets (CBs), and resin composite attachments (RCAs). Methods: Following the exposure to CHX, A+, A−, and Hr rinses for 1 min, the growth of Streptococcus mutans on MB, CB, and RCA was assessed using colony-forming units and scanning electron microscopy (SEM). Controls included attachments without intervention. In another setting, enamel with bonded attachments was exposed to mouthwashes for 1 min and subjected to cariogenic demineralization for 24 h. Enamel’s Vickers microhardness was measured before and after the demineralization challenge. Data were analyzed using paired t-tests and one-/two-way ANOVA with Tukey’s tests. Results: CHX mouthwash demonstrated superior antimicrobial efficacy against S. mutans biofilms across all orthodontic attachments (p < 0.05). On metallic brackets, CHX (0 ± 0 log₁₀) and A− (1.7 ± 0.4 log₁₀) significantly (p < 0.001) outperformed controls (6.9 ± 0.1 log₁₀), Hr (6.08 ± 0.2 log₁₀), and A+ (6.2 ± 0.6 log₁₀). Similar patterns emerged for ceramic brackets, with CHX (0 ± 0 log10) and A− (1.4 ± 0 log10) superior to controls (6.6 ± 0.4 log₁₀). On resin composite attachments, CHX (2.9 ± 0.05 log₁₀) and Hr (3.4 ± 0.08 log₁₀) exceeded controls (5.4 ± 0.09 log₁₀) in inhibiting the biofilm growth (p < 0.05). Enamel microhardness reduction was significantly influenced by attachment type (p < 0.0001) and mouthwash type (p = 0.0063), with significant interaction between variables (p = 0.0052). Conclusions: CHX and A− mouthwashes effectively inhibited S. mutans biofilms on orthodontic attachments, while attachment type and mouthwash significantly influenced enamel microhardness reduction. Full article

(1) Background: The oral cavity is a complex ecological environment that integrates elements of both the digestive and respiratory systems, contributing to its extensive microbial diversity. Despite its effectiveness, chlorhexidine is associated with undesirable effects, such as mucosal irritation and tooth staining, which have prompted research into natural alternatives. This study aimed to compare the antimicrobial activity of mouthwashes containing tea tree oil (TTO) alone and in combination with cannabidiol (CBD) and spilanthol with that of a chlorhexidine digluconate-based mouthwash (CHX) against selected oral bacterial and fungal strains. (2) Methods: To assess the antimicrobial effects of the tested mouthwashes on reference microbial strains, the agar diffusion method was applied in accordance with the guidelines of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). In addition, the microdilution method using 96-well microtiter plates was employed to determine the minimum inhibitory concentration (MIC) of the tested substances. Microbial viability was further evaluated using the WST-based colorimetric Microbial Viability Assay Kit, in which the intensity of the produced WST-formazan dye is directly proportional to the number of viable cells. (3) Results: In the disc diffusion assay, inhibition zones measured after 24 h varied among the tested microorganisms, with the largest zones observed for CHX against Candida parapsilosis (19.63 mm) and Streptococcus pyogenes (16.7 mm). In the microdilution assay against Candida albicans, the MIC₅₀ was achieved for preparations A and B at the highest tested concentrations (column 1), whereas for chlorhexidine (CHX), it was reached at lower concentrations (column 9). (4) Conclusions: ① All tested mouthwashes containing tea tree oil (TTO), either as a single active ingredient or in combination with cannabidiol (CBD) and spilanthol, demonstrated limited bacteriostatic and antifungal activity under the experimental conditions of this study. ② The chlorhexidine digluconate-based mouthwash exhibited significantly higher antibacterial and antifungal activity against all tested microbial strains compared to both the TTO-only mouthwashes and the formulation containing TTO combined with CBD and spilanthol. Full article

White Mustard (Sinapis alba) seeds contain glucosinolates, mainly sinigrin and sinalbin. Isothiocyanate metabolites, together with flavonoids and tocopherols, present anti-inflammatory, antimicrobial, and antioxidant activities. This narrative review is a result of a literature search in PubMed, Scopus, and Google Scholar, spanning in vitro, in vivo. and clinical studies. The presented data highlight that mustard-derived products suppress pro-inflammatory cytokines such as TNF-α and inhibit a broad spectrum of pathogens at micromolar concentrations. In the largest (n = 113) double-blind dental trial to date, a white-mustard toothpaste reduced the mean value of Silness-Löe plaque index by −2.43 vs. −1.95 placebo and bleeding on probing by 30.6% vs. 26.8% within four weeks, while salivary Streptococcus mutans and Porphyromonas gingival colony counts decreased by 40%. A six-month follow-up study with a sinigrin-rich “Bamberka” extract confirmed these gains and selectively suppressed red-complex periopathogens. Clinical translation is limited by heterogeneous extraction methods, a lack of phytochemical standardization, and an unresolved allergenic risk linked to seed proteins Sin a 1 and Sin a 2. Mustard, therefore, emerges as a promising phytotherapeutic adjunct for controlling inflammation, infection, and oxidative stress, but widespread use awaits harmonized manufacturing guidelines, comprehensive allergological screening, and rigorously designed randomized trials benchmarked against chlorhexidine. Full article

Objectives: To evaluate the clinical effectiveness and safety of natural products compared with chlorhexidine (CHX) as adjuncts to non-surgical periodontal therapy (NSPT) in patients with periodontitis. Materials and Methods: This systematic review was conducted in accordance with the PRISMA 2020 guidelines and registered in PROSPERO (CRD420251133219). Electronic searches of PubMed, Scopus, and Web of Science were performed to identify randomized controlled trials (RCTs) published between 2020 and 2025. Eligible studies included adult patients with periodontitis treated with NSPT, comparing CHX-based products with natural formulations (mouthwashes, gels, irrigants, or dentifrices). Data extraction included product type, concentration, mode of application, follow-up duration, and primary periodontal outcomes. Study quality was assessed using the NIH Quality Assessment Tool. Results: Thirteen randomized controlled clinical trials met the inclusion criteria. Natural products such as Curcuma longa, Morus alba, Spirulina platensis, Propolis, Triphala, and Lycium barbarum demonstrated improvements in clinical attachment level (CAL) and probing pocket depth (PPD) comparable to those obtained with CHX, along with significant reductions in bleeding on probing (BoP) and plaque index (PI). Probiotic- and ozone-based treatments also showed favorable clinical outcomes, with faster healing and fewer adverse effects, such as tooth staining and taste alteration. Follow-up periods ranged from 14 days to 3 months. Conclusions: Natural products appear to be safe and effective alternatives to CHX when used as adjuncts to non-surgical periodontal therapy, providing comparable clinical benefits with a lower incidence of side effects. Nevertheless, further large-scale, long-term randomized trials are needed to standardize formulations and concentrations and to confirm the durability of these clinical effects. Full article

Background/Objectives: Oral infections are caused by a wide spectrum of bacterial and fungal species and remain clinically challenging, particularly against the background of increasing antimicrobial resistance and efforts to reduce antibiotic use in dentistry. Platelet concentrates are widely applied in periodontal and oral surgery due to their regenerative and immunomodulatory properties, and accumulating evidence suggests additional antimicrobial effects. This study evaluated the antimicrobial activity of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and injectable PRF (i-PRF) against clinically relevant oral microorganisms. Methods: PRP, PRF, and i-PRF were prepared from venous blood of five healthy donors and evaluated using diffusion-dependent, qualitative-semiquantitative agar diffusion assays against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Staphylococcus aureus, Streptococcus mutans, Streptococcus mitis, Enterococcus faecalis, and Candida albicans, with inhibition zones assessed after species-specific incubation times. Chlorhexidine (2%) and amoxicillin served as positive controls and NaCl (0.9%) as negative control. Inhibition zones were digitally quantified and analyzed using non-parametric statistics (Kruskal–Wallis, Friedmann) due to skewed distributions and frequent zero values. Results: All platelet concentrates demonstrated microorganism-dependent inhibition zones in vitro. Overall, i-PRF demonstrated the strongest inhibitory effect across all pathogens (p < 0.001). Significant differences were detected for E. faecalis and C. albicans, where i-PRF produced markedly larger inhibition zones compared to PRP and PRF. Descriptively, anaerobic periodontal pathogens and S. aureus tended to be more susceptible, while streptococci and C. albicans demonstrated lower inhibition. Conclusions: These findings support a potential adjunctive antimicrobial role of platelet-derived preparations in dental infection management but should be interpreted with caution, as agar diffusion results do not necessarily reflect clinical performance. Full article

Background/Objectives: Multilayer zirconia restorations can feature a shade gradient or a strength gradient, with layers differing in color or phase composition within the same material. The aim of this in vitro study was to evaluate the color stability in all layers of multilayer zirconia after exposure to staining solutions and artificial aging. Methods: Square-shaped specimens (N = 120) of color A2 were fabricated from 4Y-PSZ and 3Y/4Y-PSZ multilayer zirconia—Katana STML, DD Cube One ML, and Katana YML—and their baseline color values (T0) were measured with a clinical spectrophotometer (VITA Easyshade V). The specimens were randomly divided into four groups (n = 10/gp) and immersed in physiologic solution, 0.2% chlorhexidine gluconate (CHX) mouth rinse, and staining coffee solution. Then, they were measured continuously for 7 (T1), 14 (T2), and 21 days (T3). The last group of specimens underwent accelerated aging in a steam autoclave at 134 °C and 2 bar pressure and measured after 1 (T1), 3 (T2), and 5 h (T3). After the immersion process and artificial aging, discoloration values (ΔE) were calculated using the formula ΔE = [(ΔL*)² + (Δa*)² + (Δb*)²]^1/2 and analyzed with the SPSS v 23.0 software with a p value < 0.05. Results: All specimens showed significant color differences in the T3 measurements after exposure to coffee and CHX, with the highest ΔE values in the enamel layers. Katana YML showed the most significant differences in ΔE in the cervical layers after exposure to artificial aging. Conclusions: Multilayer zirconia exhibited dependent optical changes, with the enamel layers being the most affected after exposure to staining solutions. Gradient pigmentation and differences in phase composition caused differences in color to the multilayer zirconia layers after exposure to staining solutions and artificial aging. Full article