Effect of hydrothermal aging on color stability and translucency of two zirconia generations compared to lithium disilicate ceramics.

Background: An esthetically acceptable ceramic restoration should have optical properties like the teeth and reflect, transmit, and absorb light. The present investigation compared how hydrothermal aging affected the properties of two types of zirconia and lithium disilicate. Methods: Thirty rectangular samples (12×14×1 mm) were prepared and sectioned from three different ceramic blocks/blanks (n=10), then assigned into three groups according to the ceramic type: group Z: IPS e.max ZirCAD prime, gradient zirconia (3Y/5Y-TZP); group K: Katana UTML (5Y-TZP); and group E: IPS e.max CAD (lithium disilicate). Color analysis of samples was performed before and after hydrothermal aging (1, 3, and 5 hours) using a spectrophotometer. Color difference (∆E00), translucency parameter (TP00), and contrast ratio (CR) were evaluated. The microstructural analysis was performed using x-ray diffraction (XRD). Data were statistically analyzed at a significance level of P<0.05. Results: A statistically significant variation was observed across means of ∆E00, TP00, and CR at different times. Group Z displayed the highest statistically significant mean ∆E00. Group E demonstrated the greatest statistically significant mean TP00. Group K exhibited the most statistically significant mean CR. Conclusion: Hydrothermal aging significantly affected the optical characteristics of lithium disilicate and zirconia ceramics. The translucency of samples increased with aging.

Can discolored dental composites be bleached in depth?

Objectives: Previous in vitro studies determined the whitening effects of bleaching products on stained resin composite surfaces. This in vitro study aimed to verify the effectiveness of a whitening system on composite resin previously subjected to pigmentation, specifically examining the depth of whitening effectiveness within the material structure. Materials and Methods: A commercially available nano-filled composite resin was used. Specimens were stained using a coffee-based solution and a 10% carbamide peroxide-based gel was employed as the whitening agent. The pigment's penetration and the effect of the bleaching gel were evaluated by measuring color (CieLab values) from the outer edge to the inner part of the specimens. Color measurements were taken at 14 points, starting from 0.1 mm from the external perimeter up to 3.0 mm. Results: Analysis of variance tests showed a statistically significant difference between the Control Group (CG), Pigmentation Group, and Whitening Group. The whitening agent was effective up to 1.5 mm in depth, with Whiteness index (W) values not statistically different from those of CG up to 0.5 mm in depth. Conclusions: Whitening agents on nano-filled resin composite previously pigmented appear effective in restoring the W to values similar to the original, particularly in the superficial layers of the sample.

Color stability and solubility of Biodentine and NeoPutty in contact with different irrigation solutions.

Objectives: This study aimed to evaluate the color stability and solubility of Biodentine and NeoPutty in contact with different irrigation solutions. Materials and Methods: Biodentine and NeoPutty were set in cylindrical molds with 7 mm diameter and 1.5 mm high and immersed in distilled water, 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 9% 1-hydroxyethylidene 1,1-diphosphonate (HEDP), and 5% sodium hypochlorite (NaOCl) solutions for 24 hours. The color change was measured with a spectrophotometer. The solubility values were calculated as the mass loss was expressed as a percentage of the original mass using an analytical balance with 10-4 g accuracy. Data were analyzed with Kruskal-Wallis followed by Mann-Whitney U tests, and 2-way analysis of variance test followed by Bonferroni corrections for pairwise comparisons for solubility and color stability with a 5% significance threshold, respectively. Results: Biodentine exhibited higher color changes compared to the NeoPutty contact with all solutions except distilled water (p < 0.05). Both hydraulic cements (HCs) showed higher discoloration values immersion in CHX followed by NaOCl. No statistically significant difference was found between Biodentine and NeoPutty regardless of irrigation solution in terms of solubility (p > 0.05). Solubility values were lower in the distilled water group compared to EDTA and CHX (p < 0.05). Conclusions: Tested HCs showed solubility and color changes at various rates. NeoPutty could be an appropriate material in aesthetic areas. The usage of HEDP as an irrigant solution can be considered suitable for various endodontic treatments due to its relatively lower solubility and discoloration values.

Current perspectives on calcium silicate-based intracanal medicaments: A scoping review of clinical and laboratory evidence.

OBJECTIVE: Intracanal medicaments, primarily calcium hydroxide, play a significant role in optimizing root canal disinfection. Recently, calcium silicate-based intracanal medicaments have emerged as potential alternatives. This scoping review sought to map the available evidence concerning the clinical and laboratory properties of these bioceramic medicaments. DATA: The study protocol was registered a priori (https://osf.io/rnyuv/) and a systematic search strategy using relevant MeSH terms was employed. SOURCES: The search was conducted across databases including the Cochrane Library, EMBASE, PubMed/MEDLINE, SciVerse Scopus, and Web of Science. STUDY SELECTION: Studies that investigated the clinical and laboratory properties of calcium silicate-based intracanal medicaments were included. CONCLUSIONS: Out of 1008 potentially relevant articles, 15 met the inclusion criteria. The majority of the studies came from Brazil, primarily focusing on Bio-C Temp (Angelus). The studies revealed acceptable biocompatibility, alkaline pH, and high calcium ion release. However, they showed reduced antibacterial activity compared to conventional calcium hydroxide formulations. Tooth discoloration beyond clinically acceptable thresholds was also a significant concern. A single clinical case report exhibited potential for periapical healing and root development, though this evidence is very limited. While current evidence is preliminary, high-quality clinical trials are essential to determine their clinical efficacy and safety in endodontic treatments. CLINICAL RELEVANCE: Calcium silicate-based intracanal medicaments have lower antibacterial activity and potential for tooth discoloration compared to conventional calcium hydroxide-based medicaments. Given the available evidence, they cannot be recommended for routine clinical practice.

Safety profiles of tetracycline-class drugs: a pharmacovigilance analysis of the FAERS database.

BACKGROUND: As synthesis technology advances, novel and efficient derivatives of tetracyclines are found. Three new antibiotics were approved within the past 18 years, and represent a new era in the use of tetracyclines. To gain further insight into adverse events linked to tetracyclines and better protect pediatric patients, ongoing monitoring of safety data is crucial. METHODS: The FAERS data from the first quarter of 2004 to the third quarter of 2023 in the AERSMine were extracted to conduct disproportionality analysis. The association between five tetracyclines and adverse events was evaluated using reporting odds ratio, and their risk factors were explored by multivariate logistic regression analysis. RESULTS: Our study showed that thyroid gland disorders had the strongest signal in children. Patients aged 12-18 and treatment with minocycline are risk factors for thyroid adverse events (12-18: OR = 10.727 [7.113-16.177], p < 0.0001; minocycline: OR = 17.025 [10.475-27.678], p < 0.0001). Second-generation tetracycline and third-generation tetracycline ADR patterns differed. Blood fibrinogen decreased and hypofibrinogenaemia was primarily reported with tigecycline and eravacycline. CONCLUSION: This study provided basic evidence for further research on tetracyclines-related adverse events. However, the safety of third-generation tetracycline in children requires additional validation through a large-scale prospective study.

Evaluation of Staining Propensity of Silver Diamine Fluoride With and Without Potassium Iodide in Children (Project Healthy Smiles): Protocol for a Randomized Controlled Trial.

BACKGROUND: Silver diamine fluoride (SDF) is becoming more widely recognized as a simple, cost-effective approach to minimize sensitivity and arrest caries. However, SDF results in caries that are stained black. Potassium iodide (KI) treatment with SDF may minimize or lessen the staining. However, the effectiveness of KI on staining has not been investigated. Studies demonstrating that potassium iodide reduces the black staining are still insufficient. This paper presents the study protocol for Healthy Smiles, a randomized controlled trial implemented to compare the staining propensity of SDF and SDF+KI. OBJECTIVE: This study, Healthy Smiles, aims to evaluate the staining propensity of SDF and SDF+KI using a Nix Mini color sensor among children aged 4 to 6 years. Another objective of the study is to evaluate the caries-arresting effect of SDF and SDF+KI in the treatment of carious primary teeth. METHODS: This study is a randomized controlled trial. A total of 60 children with caries that meet the criteria of the International Caries Detection and Assessment System (code 1 or above) will be randomly assigned to treatment groups, where group 1 will be treated with SDF and group 2 will be treated with SDF+KI. Discoloration of treated lesions will be assessed digitally using a Nix Mini color sensor. Participants will be followed up at 1, 3, and 6 months after treatment to digitally record the ∆L and ∆E values using the Nix Mini color sensor. Data will be analyzed using SPSS (version 28; IBM Corp). Independent sample t tests and the Mann-Whitney U test will be used to compare the 2 groups. RESULTS: Enrollment started in October 2023. It is estimated that the enrollment period will be 12 months. Data collection is planned to be completed in 2024. CONCLUSIONS: The presented paper describes Happy Smiles, a project that provides an opportunity to address the aesthetic inconvenience of patients without compromising the effectiveness of the SDF treatment. The trial findings will contribute to the limited evidence base related to discoloration after SDF intervention to improve aesthetic appearances in child oral health. If the results from the trial are promising, it will lead to the development of a model for child oral health and pave the way for further research in child oral health. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/51087.

Evaluation and Comparative Analysis of Coronal Tooth Discoloration Induced by Four Endodontic Biomaterials Utilized in Regenerative Endodontic Procedures: An Ex-vivo Study.

AIM: This study aims to compare and evaluate the changes in color caused by four different biomaterials utilized as intracanal coronal barriers in the regenerative endodontic procedure at varying intervals of time. METHODS: A total of 100 extracted mandibular single-rooted premolars were taken. Samples were standardized, and access cavity preparation was done. All the canals were instrumented and irrigated thoroughly. They were divided into five groups: A, B, C, D, and E (n=20), i.e., the control group, gray mineral trioxide aggregate (MTA), white MTA, Biodentine, and calcium hydroxide. Each group was further subdivided into two subgroups (n=10), where one subgroup was prepared with normal saline and the other was prepared with platelet-rich fibrin (PRF). Digital photographs were taken at baseline, immediately after the placement of biomaterials, after 72 hours, seven days, and six months, using a DSLR camera. The color evaluation was done using the Adobe Photoshop 2021 software using the CIE L*a*b color system. The data obtained were recorded and statistically analyzed using IBM SPSS Statistics for Windows, Version 23 (Released 2015; IBM Corp., Armonk, New York). Continuous variables were analyzed using a one-way ANOVA test and post-hoc analysis. The P-value was set to be significant at <0.05. RESULTS: Statistically significant variation was obtained in all four experimental groups regarding change in color (ΔE) over periods of 72 hours, seven days, and six months. At six months, all the experimental groups presented with a perceptible color variation (ΔE>3.3). CONCLUSION: The color change was significant after six months in all groups. Biodentine produced the least color alteration, whereas gray MTA produced the highest.

Two Cases of Children With Black Hairy Tongue and Tooth Discoloration Caused by Antibacterial Agents.

Black hairy tongue (BHT) is a lesion in which the filiform papillae of the tongue are significantly extended by hyperkeratosis, thereby giving the tongue a hairy appearance. Here, we report two rare cases of children with BHT and tooth discoloration caused by antimicrobial agents. Case 1: A four-year-old female patient received intravenous linezolid after spinal surgery, and BHT developed on day eight of treatment. Subsequently, the patient developed teeth discoloration. Linezolid was continually administered for 50 days, and BHT and teeth discoloration improved 10 days after the end of linezolid treatment. Case 2: A two-year-old male patient with a brain abscess received intravenous meropenem and vancomycin. On the fourth day of treatment, BHT developed, and teeth discoloration was subsequently observed. Antibiotic therapy was continued for 82 days, and BHT and tooth discoloration improved 20 days after the treatment was discontinued.

Evaluation of the effects of different photosensitizers used in antimicrobial photodynamic therapy on tooth discoloration: spectrophotometric analysis.

BACKGROUND: Tooth discoloration is a common concern in antimicrobial photodynamic therapy (aPDT) using various photosensitizers (PS). Toluidine Blue (TB), Methylene Blue (MB), Phthalocyanine (Pc), and 2-mercaptopyridine-substituted zinc phthalocyanine (TM-ZnPc) are among those studied, but their relative impacts on tooth discoloration remain unclear. AIM: This study aimed to compare the effects of TB, MB, Pc, and TM-ZnPc in aPDT on tooth discoloration, utilizing a controlled experimental setup. MATERIALS AND METHODS: The study comprised seventy-five single-rooted incisors with root canals. Following meticulous preparation, a standardized area on the crown surface was designated for examination, and precise measurements of the initial tooth colors were recorded. Samples were randomly divided into five groups: Negative control, MB, TM, Pc, and TM-ZnPc. Photoactivation was performed using LED light, and color measurements were taken at multiple time points up to 90 days. Data were converted to Lab* color values of the CIE Lab* color system (International Commission on Illumination, Vienna, Austria), and ΔE values were calculated. Statistical analysis was performed using Two-way ANOVA and Post-Hoc Tukey tests (p < 0.05). RESULTS: At day 7 and 30, TM-ZnPc and Pc caused less discoloration compared to MB and TB. TM-ZnPc caused more tooth discoloration compared to Pc (p < 0.05). Compared to baseline, MB and TM-ZnPc caused more tooth discoloration at 30 days and TB caused more tooth discoloration at 90 days (p < 0.05). No significant difference was observed in terms of tooth discoloration at all periods evaluated after Pc application (p > 0.05). All photosensitizers tested in the study caused tooth coloration. CONCLUSION: All PS induced clinically detectable tooth discoloration, with TB and MB causing more significant discoloration compared to Pc and TM-ZnPc at certain time points. TM-ZnPc and Pc demonstrated more stable coloration levels over time, suggesting their potential reliability in aPDT applications. This study highlights the importance of selecting appropriate PS to minimize tooth discoloration in aPDT, with Pc showing promise in this regard.

Inverted Layering Technique as a Biomimetic Procedure in a Multidisciplinary Resolution of Discolored Teeth: A Case Report.

The objective of this work is to report a restorative approach with composite resin applied in reverse in the aesthetic resolution of darkened anterior teeth. A 27-year-old female patient presented with the main complaint of dissatisfaction with the aesthetics of her smile due to dental darkening, a result of childhood trauma, without painful symptoms, pathological clinical signs or change in care. In the intraoral examination, a darkening of teeth 11 and 21 was observed, which radiographically showed thickening of the periodontal ligament, with disharmonious configuration of the marginal gingiva. From the clinical and radiographic characteristics, we opted for periodontal intervention for recovery and gingival levelling, followed by endodontic intervention and aesthetic restorative restoration. The restorative step was carried out sequentially by internal tooth bleaching, removal of dentin still pigmented after bleaching and enamel preservation. Soon after, it was restored in an alternative way and layered using a technique called reverse, using strips of polyethylene fiber over the dentin resin. The technique preserved the remaining enamel with the maintenance of the original remaining guides, proving to be a viable conservative alternative since of the diagnosis to the restorative conclusion in view of the longitudinal confirmation of the restorative efficacy after 1 year.

Tetracycline staining of the dentition: a review of the literature and report of a clinical case.

The present article reviews the literature regarding tetracycline staining of the dentition and its esthetic management. A total of 49 articles were identified in the initial search, and 22 articles met the eligibility criteria of this narrative literature review. Tetracycline staining results from its use in children between the ages of 6 months and 6 years, when tooth crowns are formed; the effects are dependent on the dosage, duration of treatment, stage of tooth mineralization, and activity of the mineralization process. Tooth bleaching is always the first treatment option for low-grade cases of tetracycline staining. Restorative procedures are indicated for severe staining. The article also describes the treatment of severe staining affecting the maxillary anterior dentition of a 48-year-old man who reported the systemic administration of tetracycline during childhood. Direct composite resin laminate veneers were proposed to achieve immediate, highly esthetic restorations. A combination of different resinous materials in different shades was applied to meet the needs of the patient. The use of direct composite resin laminate veneers satisfied the functional and esthetic demands of the patient at a lower cost than ceramic materials.

Whitening Efficacy of Toothpastes on Coffee-Stained Teeth: An Enamel Surface Analysis.

AIM: This study aimed to identify the optimal toothpaste for removing coffee-induced stains while also evaluating its impact on tooth enamel through roughness and abraded depth parameters, providing a comprehensive understanding of their effects. MATERIALS AND METHODS: Three whitening toothpastes and 2 conventional toothpastes were prepared for a simulated brushing procedure on coffee-stained bovine enamel tooth specimens. Using a toothbrushing machine, up to 10,000 brushstrokes were completed, while spectrophotometric readings were taken at designated intervals. A mixed-effects model for statistical analysis determined the effects of toothpaste and brushing on colour change, roughness, and abraded depth. RESULTS: Whitening toothpastes significantly deviated from the control (P < .001, P < .001, and P < .003, respectively), whereas the conventional toothpaste did not exhibit a significant contrast (P < .081). Regarding colour restoration following coffee staining, whitening toothpastes showed higher restoration than conventional toothpastes. Surface roughness and abraded depth parameters increased with accumulated brushing. CONCLUSIONS: Sodium hexametaphosphate-containing toothpaste demonstrated the highest efficacy in removing coffee-induced stains and restoring tooth colour. Nevertheless, this stronger whitening effect was associated with increased abrasion. While conventional toothpastes exhibited some whitening effects, the most substantial improvement in lightness was consistently observed with whitening toothpastes. CLINICAL RELEVANCE: Understanding how whitening toothpaste affects enamel integrity is crucial for refining formulations and advancing dental care. This knowledge lays the groundwork for more effective oral care products and improved whitening procedures, ultimately enhancing the overall quality of dental treatments.

Long-Term Success of Regenerative Endodontic Treatment in Managing Traumatized Teeth: A Case Report With Seven-Year Follow-Up.

Traumatic injuries to maxillary incisors often result in complex dental complications, such as pulp necrosis and periapical pathology, particularly in young patients. Traditional root canal treatments may prove insufficient, especially for immature teeth requiring apexification. Regenerative endodontic treatment (RET) presents a promising alternative, aiming to eliminate infection while fostering root development and tooth vitality. This case report illustrates the successful management of a necrotic-infected traumatized maxillary incisor in a seven-year-old girl using RET. The treatment involved a meticulously planned protocol comprising disinfection, induction of bleeding, and placement of a calcium-enriched mixture (CEM) cement plug, followed by composite restoration. Remarkably, despite the initial detection of an endodontic lesion in the postoperative radiograph, the clinical outcomes remained aesthetically pleasing, with subsequent radiographs revealing regression of the apical lesion and complete tooth maturation over the seven-year follow-up period. This case highlights the efficacy and feasibility of RET using CEM in managing infected, traumatized teeth, emphasizing its potential for long-term healing and functional restoration. The absence of tooth discoloration further underscores the benefits of utilizing specific materials and protocols.

The Efficacy of Different Antibiotic Compounds in Regenerative Treatment of Immature Necrotic Teeth.

Objectives: Endodontic treatment of immature teeth poses a significant challenge, especially in achieving a proper seal using traditional obturation methods. Revascularization presents itself as an alternative approach to this problem, and the application of triple antibiotic paste (TAP) has been suggested as a means to achieve disinfection during the procedure. This study aims to compare the antibacterial properties of three different antibiotic combinations to assess their effectiveness on root canal disinfection. Materials and Methods: Eighty samples were employed to assess the impact of three antibiotic combinations on Enterococcus faecalis, Escherichia coli, Streptococcus mutans, and a combination thereof. The antibiotics included metronidazole, ciprofloxacin, and cefaclor (CCM), the commonly used TAP, and a double antibiotic paste (DAP) composed of metronidazole and ciprofloxacin. Dentin shavings collected using Gates-Glidden drills were placed in microtubes containing a 2ml standard bacterial suspension. Microtube contents were diluted and cultured on BHI agar plates, with colony counts calculated based on dentine shavings' weight in CFU/mg. Kruskal-Wallis and Dunn's post-hoc tests were used for statistical analysis and P<0.05 was considered significant. Results: A significant difference in mean CFU was observed among all bacterial groups (P<0.05). Dunn's post-hoc analysis showed a significant difference only between the control group (methylcellulose) and the other antibiotic groups. There was no significant difference between the other antibiotic groups in two-by-two comparisons. Conclusion: There was no significant difference in the antimicrobial properties of DAP, TAP and CCM. Therefore, DAP and CCM may be used during regenerative treatment.

Tooth whitening: current status and prospects.

As a safe, effective, economical, and convenient technique, tooth whitening is one of the most popular treatments for improving tooth discoloration. This review summarizes the theoretical and recent research developments in the classification and mechanisms of tooth discoloration, as well as the principles, agents, effects, and side effects of tooth whitening techniques. The aim is to provide a basis for the clinical treatment of tooth whitening techniques and to suggest possible new ideas for further research. The accepted mechanism of whitening is the redox reaction of oxides in the whitening reagent, and the whitening effect is remarkable. However, side effects such as tooth sensitivity and irritation of gum and other oral soft tissues can still occur. It is recommended that more monitoring be carried out in the clinic to monitor these side effects, and care should be taken to protect the soft tissues in the mouth during office whitening procedures. Furthermore, there is a need to develop new additives or natural whitening products to reduce the occurrence of side effects.

Evaluation of pediatric dentists' knowledge and approaches to tooth discoloration.

In recent years, esthetic expectations have come to the fore in pediatric dentistry, as in every field of dentistry. Therefore, to better meet patients' expectations, the steps taken to determine and improve the current level of knowledge of pediatric dentists on tooth discoloration gain importance. This study aims to measure the knowledge levels of pediatric dentists regarding tooth discoloration. A 33-questioned survey created online was emailed to pediatric dentists between March and December 2021. The first part included four multiple-choice and two open-ended questions regarding demographic characteristics. The second part was to measure the participants' knowledge of tooth discoloration. The last part was to evaluate the clinical approaches of the participants. Participants who agreed to answer all of the questions were included in the study (n = 129). The knowledge levels of the participants were scored according to the accuracy of their answers. The data were statistically analyzed using descriptive statistics and chi-square tests. Of the pediatric dentists who participated in this study, 16.3% had high knowledge, 79.8% had medium knowledge, and 3.9% had insufficient understanding of tooth discoloration. There was no correlation between time since dental school graduation and time spent practicing as a pediatric dentist (p > 0.05). The group with the highest average level of knowledge was the group most frequently encountered with tooth discoloration in the clinic (p ≤ 0.05). On average, pediatric dentists had moderate knowledge of tooth discoloration. The group with the highest average expertise in this field was the group that most frequently encountered and treated tooth discoloration. Information on tooth discoloration due to systemic factors was insufficient. To increase the knowledge level of pediatric dentists about the causes and treatments of tooth discoloration, it may be beneficial to establish training programs during and after specialization education.

The Efficacy of Different Laser Applications on Dentin Sealing in Preventing Discoloration Induced by Mineral Trioxide Aggregate.

The aim of this in vitro study was to evaluate the effect of the pre-application of a dentin-bonding agent and the application of different lasers on the prevention of tooth discoloration caused by mineral trioxide aggregate (MTA) in the presence of blood. Sixty extracted human anterior teeth were selected, with root lengths standardized to 10 mm and root canals shaped using Gates-Glidden drills #3 to #5. The samples were divided into six groups (n = 10): Group 1 with no surface treatment and Groups 2 to 6 with Optibond universal adhesive and Neodymium yttrium aluminum garnet (Nd:YAG), Erbium yttrium aluminum garnet (Er:YAG), Erbium-chromium-yttrium-scandium-gallium-garnet (Er:Cr:YSGG), and diode laser applications, respectively. Root canals were filled with fresh human blood, and ProRoot MTA and a collagen barrier were then placed. Color changes were measured with a spectrophotometer at 0, 7, 30, 90, and 180 days post MTA placement. Color differences (∆E) were analyzed using a two-factor mixed-design ANOVA with the Sidak method (p = 0.05). All treatment groups exhibited discoloration above the acceptability threshold. Although all treatment approaches exhibited less color change compared to the control group (p < 0.05), there was no significant difference among them in terms of preventing color change (p > 0.05). It was determined that none of the methods could guarantee 100% prevention of discoloration caused by MTA-blood contact.

Influence of Post-Curing in Nitrogen-Saturated Condition on the Degree of Conversion and Color Stability of 3D-Printed Resin Crowns.

Post-curing is the process of applying extra light to complete the polymerization process of 3D printing. The mechanical properties of light-cured three-dimensional (3D) printed resin can be improved by decreasing the oxygen concentrations during post-curing, and nitrogen-saturated post-curing has been applied for this purpose. This study aimed to evaluate and compare the color stability of 3D-printed resin crowns that were post-cured in both normal air and nitrogen-saturated conditions. Crowns were fabricated with a 3D printer and post-cured in normal air (control group; air) or nitrogen-saturated conditions (experimental group; nitrogen). The specimens in each group were subdivided into four subgroups, each exposed to different discoloration agents: distilled water, coffee, wine, and curry. Post-immersion color changes were measured using a digital spectrophotometer and analyzed using repeated-measures ANOVA. Fourier transform infrared (FT-IR) spectroscopy evaluated the degree of conversion of resin over immersion times for both post-curing conditions. Upon comparing the effects of post-curing conditions, a significant difference between the control and experimental groups in terms of immersion time in the wine and curry subgroups was found. FT-IR analysis showed a significant difference in the degree of conversion between the air and nitrogen groups from 10 to 300 s. These findings suggest that nitrogen-saturated post-curing can potentially enhance the conversion rate of 3D-printed resin crowns, thereby improving their color stability.

[Laboratory evaluation of the effectiveness and safety of the Chairside Light Whitening System fläsh]. / Laboratornaya otsenka effektivnosti i bezopasnosti otbelivayushchei sistemy Chairside Light Whitening System fläsh.

THE AIM OF THE STUDY: Optimization of methods for treating dental discoloration using whitening systems based on hydrogen peroxide by laboratory studying their chemical properties. MATERIAL AND METHODS: The effectiveness of the bleaching system was assessed by quantitatively assessing the color change of model samples of hydroxyapatite (HAP) in the CIE L*a*b* system on a Spectron-M color analyzer after exposure to coloring food media. Safety assessment was carried out on samples made from teeth removed according to indications. RESULTS: The results of laboratory tests allow us to conclude that the Chairside Light Whitening System professional teeth whitening system fläsh. (WHITEsmile GmbH, Germany) has high whitening efficiency with a whitening degree of ~84%, which significantly exceeds the norm of GOST R 702.3.004-2021. the microhardness of the enamel of samples exposed to the whitening gel for 15 minutes changes extremely little. After exposure of the studied samples to the Chairside Light Whitening System fläsh whitening system for 45 minutes, an increase in digital microhardness indicators is observed, which indicates the dynamics of processes demineralizing the hard tooth structure. CONCLUSIONS: Chairside Light Whitening System fläsh professional teeth whitening system has high whitening efficiency with minimal impact on the teeth structure and high safety.

An in vitro evaluation of the effects of fluoride, CPP-ACP, or resin infiltration on discoloration caused by pediatric supplements.

OBJECTIVES: White spot lesions are more susceptible to staining agents due to their porous structure. This study examines the impact of white spot lesion treatments on discoloration caused by pediatric supplements. METHOD AND MATERIALS: Three treatments (fluoride, casein phosphopeptide-amorphous calcium phosphate [CPP-ACP], resin infiltration), a control, and their respective syrup-based subgroups (iron and black elderberry syrups) were established, each with eight teeth. Artificial white spot lesions were induced, and weekly applications of fluoride varnish, daily applications of CPP-ACP paste, or a single resin infiltration procedure were performed on the white spot lesions within the treatment groups over 4 weeks. Simultaneously, samples were exposed daily to iron or black elderberry syrups. Spectrophotometer measurements were taken at baseline, after demineralization (T0), and after 1 (T1), 2 (T2), and 4 weeks (T4). ΔE00 values were calculated. Statistical analysis was conducted using a three-way mixed-design ANOVA, with the significance level set at P = .05. RESULTS: At T4, ΔE00 values from all groups exceeded the clinical acceptability limit of 1.8. At T2 and T4, the ΔE00 values obtained from the black elderberry syrup subgroups were significantly higher (P < .001). At T4, the highest ΔE00 values were seen in the CPP-ACP groups (P < .001). The lowest ΔE00 values at T2 and T4 were observed in the resin infiltration groups (P < .05). CONCLUSIONS: Supplements containing ferrous sulfate and black elderberry extract caused color changes in white spot lesions that exceeded the clinical acceptability limit. Resin infiltration of white spot lesions provides advantages over remineralization treatments, particularly in minimizing discoloration induced by pediatric supplements.