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Reducing treatment time is one of the most important trends in modern dentistry. This study aimed to compare the micro-leakage around the resin sealants when using both high and conventional intensity light-curing systems. The study sample consisted of 30 extracted human maxillary premolar teeth that were divided into two equal groups according to the light-curing system used: Group 1, High-Intensity Light-Curing System and Group 2, Conventional Light-Curing System. Light-curing by Woodpecker I-LED device with two intensities (high and conventional) has been used. All teeth were subjected to 500 cycles of thermocycling. Then, a methylene blue dye microleakage test was performed, and the teeth were sectioned longitudinally and studied under a stereo microscope. The mean of micro-leakage in the high-intensity group (1.33 ± 1.29) was less than in the conventional intensity group (1.63 ± 1.29) without any statistically significant differences (p = 0.320). The high-intensity light-curing system mode may be a good and acceptable alternative to conventional intensity light-curing system mode in polymerization of pits and fissure sealants.

Purpose: The aim of this in vitro study was to evaluate the influence of different models of commercially available portable dental radiometers on the measurement of light irradiance emitted by light-emitting diode (LED) photocuring units. Materials and Methods: Eight LED photocuring units, all emitting light in a single-wavelength spectrum, were tested. Light irradiance (mW/cm2) was measured using six portable dental radiometers: four digital models (D1–D4) and two analog models (A1, A2). Digital model D1 was used as the reference (control). All measurements were conducted under standardized conditions, and each LED–radiometer combination was tested in triplicate. Data were analyzed using Sigma Plot 12.0 (Palo Alto, CA, USA) to verify the assumptions of normality and homogeneity of variances. A one-way analysis of variance (ANOVA) was used to assess the effect of the radiometer model on irradiance values, followed by Tukey’s post hoc test for multiple comparisons. The significance level was set at α < 0.05. Results: No statistically significant difference in irradiance was found between D1 (control) and D2. However, significantly lower values were recorded with A2, while D3, D4, and A1 produced significantly higher irradiance values compared to the control (p < 0.05). Conclusion: Irradiance measurements can vary significantly depending on the radiometer model used. Clinicians should be aware of this variability and are encouraged to regularly check the irradiance of the light-curing units used in daily practice, ensure their proper maintenance, and implement periodic monitoring to maintain effective clinical performance.

This study aimed to investigate the impact of the duration of light curing unit (LCU) usage and the use of infection control barriers on the hardness of Bulk Fill composite resin after curing. The hypotheses were that extended usage of the LCU would not reduces its output power and resin hardness, and that the presence of polyethylene film barriers exacerbates the reduction in resin hardness. Based on the absence or presence of polyethylene film (PE) and the number of layers used, a 3M LED curing light (EliparTM DeepCure-S; 3M ESPE, St Paul, MN, USA) was divided into three groups: PE0, PE1, and PE3. The curing light was used 30 times daily for 20 s per exposure, at frequencies of 0, 6, and 12 months. Maximum output power tests were conducted for each group of curing lights. Custom-made plastic modules were used to stack Bulk Fill composite resin (Filtek Bulk Fill Posterior Restorative; 3M ESPE) to a thickness of 4 mm. Each group of curing lights was used to cure the modules in a direct contact manner for 20 s. Vickers hardness measurements were taken at the top and bottom surfaces of the resin specimens using a digital microhardness tester. A one-way or two-way ANOVA analyzed the power of LCUs, Vickers hardness of Bulk Fill composite resin, and hardness decrease percentage across groups. Pairwise comparisons used the Tukey test (α = 0.05). As the duration of usage increased, both the power of the curing light and the hardness of the resin significantly decreased. Significant differences were observed in power and resin hardness among the PE0, PE1, and PE3 groups. When the duration of usage was 6 months or less, only multi-layered PE films led to a significant increase in the percentage decrease of hardness of cured resin from top to bottom. However, at 12 months, both single-layer and multi-layered PE films resulted in a significant increase in the percentage decrease of hardness of cured resin from top to bottom. The output power of the light curing unit decreases with prolonged usage, thereby failing to meet the curing requirements of Bulk Fill composite resin. The use of single-layer PE as an infection control barrier is recommended.

Objective: The aim of this study was to evaluate clinical success of primary teeth class II lesions restored with different restorative materials [Hybrid Composite Resin (HCR), Resin Modified Glass Ionomer Cement (RMGIC), compomer, and Giomer Composite Resin (GCR)] followed up for 24 months. Study Design: This study was carried out on 146 primary molars of 41 children in the age range of 5–7 years. The class II lesions in primary molars of a patient were restored using different restorative materials. Restorations were evaluated according to FDI-criteria and their survival rates were determined. Data were analysed with Pearson chi-square, Kaplan-Meier and Wilcoxon (Breslow) tests (α = 0.05). Results: The failure rates of restorative materials were as follows: compomer 33.3%, RMGIC 28.1%, HCR 22.5% and GCR 21.1%. Conclusions: While the functional failure was the most important factor in restorative material failure, RMGIC was the most successful material in terms of biological evaluation criterion and GCR had the longest survival rate.

This study investigated polymerization kinetics, linear shrinkage, and shrinkage stress development for six contemporary composite materials of different viscosities cured using radiant exitances of 1100–2850 mW/cm2. Real-time measurements of degree of conversion, linear shrinkage, and shrinkage stress were performed over 5 min using Fourier-transform infrared spectrometry, a custom-made linometer, and a custom-made stress analyzer, respectively. For most tested variables, the factor “material” had a higher effect size than the factor “curing protocol”. Maximum polymerization rate and maximum shrinkage stress rate were the most affected by changes in curing conditions. In contrast, no significant effects of curing conditions were identified within each material for shrinkage stress values measured at the end of the 5 min observation period. Linear shrinkage and shrinkage stress values measured after 5 min were closely correlated (R = 0.905–0.982). The analysis of polymerization kinetics suggested that the two composites specifically designed for rapid light-curing responded to higher radiant exitances differently than other composites. Polymerization kinetics and shrinkage stress behavior of contemporary restorative composite materials of different viscosities were overall more affected by material type than differences in curing conditions. Subtle differences in polymerization kinetics behavior shown by the two composites specifically designed for rapid high-intensity light-curing did not translate into significant differences in the development of polymerization shrinkage stress.

To evaluate the marginal sealing of resin composite restorations subjected to various light-curing protocols, both with and without artificial aging through thermocycling.  A comparative, longitudinal in vitro experimental study was performed with 120 bovine teeth distributed across 8 groups. The teeth were treated with different light intensities (650-1200 mW/cm², 800 mW/cm², 1200 mW/cm², 2500-2800 mW/cm²) along with different curing times (15\", 20\", 10\", 3\"), as described in the ISO 11405-2015 standard. Thermocycling comprised of 10,000 cycles to replicate one year of intraoral conditions, and microleakage was measured with dye penetration and the Khera and Chan scale (0-3). The majority of samples (41.7%) displayed dye penetration in the middle third of the interface (grade 2). Significant differences were detected among samples with and without thermocycling in the specific groups (p=0.027 and p=0.013), confirming a possible effect of artificial aging. For the highest light intensities (2500-2800 mW/cm²), no significant differences were present (p=0.527), indicating a possible lower effect of thermocycling at these intensities. The results demonstrate that marginal sealing varies by curing protocols and aging processes. Thermocycling affected microleakage with moderate light intensity, while higher intensities and shorter curing times had a reduced effect. These results point to the need for optimizing the curing protocols to provide better long-term durability for the restoration. Further work should examine other variables that may alter marginal sealing. Evaluar el sellado marginal de restauraciones de composite resinoso sometidas a diversos protocolos de fotopolimerización, con y sin envejecimiento artificial mediante termociclado.  Se realizó un estudio experimental in vitro longitudinal comparativo con 120 dientes bovinos distribuidos en 8 grupos. Los dientes fueron tratados con diferentes intensidades de luz (650-1200 mW/cm², 800 mW/cm², 1200 mW/cm², 2500-2800 mW/cm²) junto con diferentes tiempos de polimerización (15«, 20», 10«, 3»), tal y como se describe en la norma ISO 11405-2015. El termociclado consistió en 10.000 ciclos para replicar un año de condiciones intraorales, y la microfiltración se midió con penetración de colorante y la escala de Khera y Chan (0-3). La mayoría de las muestras (41,7%) presentaban penetración de colorante en el tercio medio de la interfase (grado 2). Se detectaron diferencias significativas entre las muestras con y sin termociclado en los grupos específicos (p=0,027 y p=0,013), lo que confirma un posible efecto del envejecimiento artificial. Para las intensidades de luz más altas (2500-2800 mW/cm²), no se presentaron diferencias significativas (p=0,527), lo que indica un posible menor efecto del termociclado a estas intensidades. Los resultados demuestran que el sellado marginal varía según los protocolos de curado y los procesos de envejecimiento. El termociclado afectó a la microfiltración con una intensidad de luz moderada, mientras que las intensidades más altas y los tiempos de curado más cortos tuvieron un efecto reducido. Estos resultados apuntan a la necesidad de optimizar los protocolos de polimerización para proporcionar una mejor durabilidad a largo plazo de la restauración. En futuros trabajos deberán examinarse otras variables que puedan alterar el sellado marginal.

Purpose Despite the aesthetic advantages of composite resins, polymerization shrinkage leads to microgaps, microleakage, and restoration failures. Various light-curing devices and techniques have been developed to reduce polymerization shrinkage; however, microleakage has not been completely prevented. High light intensity can shorten treatment time but may also increase polymerization stresses, potentially leading to increased microleakage. This study aimed to investigate the effects of different light intensities and application directions on microleakage. Methods In this study, 48 caries-free incisor teeth were used. Black V cavities were prepared for the teeth. Teeth were divided into three groups according to the direction of light application (Labial, Incisal, Lingual) and two subgroups according to the different light device types[Woodpecker i LED(2500 mW/cm 2 ), 3 M ESPE Elipar (1200 mW/cm 2 ) ]. Composite resins were polymerized from different directions and for different durations. All samples were analyzed for microleakage using basic fuchsin dye and a stereomicroscope. Data were evaluated using the Kruskal-Wallis test in SPSS 20.0 software. Results The type of light-curing device did not result in a statistically significant difference in microleakage ( p  = 0.274) Microleakage at the gingival margin was significantly higher than that at the incisal margin ( p  = 0.000) A difference was observed between the groups based on the light application direction, and a statistically significant difference was identified between the incisal and lingual directions ( p  = 0.002). Conclusion Polymerization shrinkage is a multifactorial problem. High light intensity reduces working time but increases polymerization shrinkage. The direction of light application was found to affect microleakage. For clinical success, light intensity, application direction, and material selection should be considered together.

This review article will discuss the origin of resin-based dental composite materials and their adoption as potentially useful adjuncts to the primary material used by most dentists for direct restorations. The evolution of the materials, largely driven by the industry’s response to the needs of dentists, has produced materials that are esthetic, strong, and versatile enough to be used in most areas of the oral cavity to replace or restore missing tooth structures. Significant advancements, such as the transition from chemical to light-curing materials, refinements in reinforcing particles to produce optimum polishing and wear resistance, formulating pastes with altered viscosities to create highly flowable and highly stiff materials, and creating materials with enhanced depth of cure to facilitate placement, will be highlighted. Future advancements will likely reflect the movement away from simply being a biocompatible material to one that is designed to produce some type of beneficial effect upon interaction within the oral environment. These new materials have been called “bioactive” by virtue of their potential effects on bacterial biofilms and their ability to promote mineralization of adjacent tooth structures.

Background To evaluate the temperature values including initial, maximum, and rising caused by light-cured materials used for direct capping during polymerisation. Methods A 3 mm deep, wide, and length class-I cavity was prepared to a premolar tooth, leaving hard tissue at the pulpal floor of 1 mm thickness with a 1 mm diameter of exposure. The sample was placed in a customised mimicry setup in which the temperature was standardised (37 °C) by a double-verified system. Light-curing capping materials (Theracal LC, Theracal PT, Harvard BioCal, and Ultrablend Plus) were placed, polymerised, and temperature values were recorded. Kruskal-Wallis test was used to compare parameters among groups, and Dunn’s test was used to define the group that caused the difference ( p  < 0.05). Results There were statistically significant differences between the materials in terms of initial, maximum, and temperature rising values (p in =0.014, p max =0.034, p tr = 0.016). The values of Theracal PT were measured highest in terms of temperature increase, while no statistically significant difference was observed between other materials during polymerisation. Conclusions Theracal PT caused higher temperature rise, however, it did not exceed 5.6 °C, which is the critical value for the pulp. Theracal PT should be used with caution as its use during direct capping causes high temperature increases, and there is a need for a light-curing regime to be designed for its use.

Under clinical conditions, conventional glass-ionomer dental cements can be cured by application of heat from dental cure lamps, which causes acceleration in the setting. In order for this to be successful, such heat must be able to spread sufficiently through the cement to enhance cure, but not transmit heat so effectively that the underlying dental pulp of the tooth is damaged. The current study was aimed at measuring heat transfer properties of modern restorative glass-ionomers to determine the extent to which they meet these twin requirements. Three commercial glass ionomer cements (Ionofil Molar, Ketac Molar and Equia™ Fill) were used in association with three different light emitting diode cure lamps designed for clinical use. In addition, for each cement, one set of specimens was allowed to cure without application of a lamp. Temperature changes were measured at three different depths (2, 3 and 4 mm) after cure times of 20, 40 and 60 s. The difference among the tested groups was evaluated by ANOVA (P < 0.05) and post hoc Newman–Keuls test. All brands of glass-ionomer showed a small inherent setting exotherm in the absence of heat irradiation, but much greater temperature increases when exposed to the cure lamp. However, temperature rises did not exceed 12.9 °C. Application of the cure lamp led to the establishment of a temperature gradient throughout each specimen. Differences were typically significant (P < 0.05) and did not reflect the nominal power of the lamps, because those lamps have variable cooling systems, and are designed to optimize light output, not heating effect. Because the thermal conductivity of glass-ionomers is low, temperature rises at 4 mm depths were much lower than at 2 mm. At no time did the temperature rise sufficiently to cause concern about potential damage to the pulp.Temperature gradient through glass-ionomer (EquiaFil exposed to Bluephase Style lamp)