Operative dentistry最新文献

Objective: To evaluate the influence of battery level on power (mW), emission spectrum (mW/cm2/ nm), and light distribution on the active tip (mW/ cm2) of certified (FDA/ANVISA) and low-cost uncertified light-curing units (LCUs) purchased through e-commerce.

Methods: Seven LCUs, three certified: VALO Grand (Ultradent); Radii Xpert (SDI); and LED.B (Woodpecker); and four uncertified: 1 Sec; BS 300; LED curing light; and VAFU (VRN, AZDENT), were used. The LCUs were evaluated by calculating the power (mW) after each sequential five exposure cycles of 20 seconds and the emission spectrum (mW/cm2/nm) in the initial and final cycles, using an integrating sphere during three battery charging cycles. Beam profiling was used to check the light distribution on the LCU tip after every 50 exposure cycles until the battery fully discharged. Data were analyzed by linear regression between power and the number of exposure times (R2).

Results: The certified LCUs VALO Grand (R2=0.005), LED.B (R2=0.02), and Radii Xpert (R2=0.09) and the uncertified LCU VAFU (R2=0.002) had no significant power reduction during the three battery charging cycles. The uncertified LCUs BS 300 (R2=0.87), 1 Sec (R2=0.60), and LED curing light (R2=0.83) showed significant power reduction, decreasing the emission spectrum (mW/cm2/nm) at the end of the battery charging cycle. The light distribution on the active tip across the level battery was modified significantly with successive exposure times.

Conclusions: The certified LCUs (VALO Grand, Radii Xpert, and LED.B) and uncertified LCU (VAFU), maintained power, emission spectrum, and light distributions during the tested battery life cycles. Low-cost certified LCU LED.B exhibited inhomogeneous light concentrated at the center of the tip. Low-cost uncertified LCUs-BS 300, 1 Sec, and LED curing light-had significant power reductions during the battery cycles and increased inhomogeneous light distribution along the successive exposure times.

Objectives: This case report describes a digital workflow for designing and 3D printing a guide with the dual purpose of gingivectomy and tooth preparation in the esthetic zone, to be followed by cementation of ceramic veneers under rubber dam isolation.

Clinical considerations: The patient's primary concern was to improve her smile. After clinical evaluation, our recommendation was for a minimal gingivectomy to match the gingival zenith for both central incisors, to be followed by ceramic laminate veneers. A digitally designed and 3D printed guide was used for gingivectomy and tooth preparation for the ceramic veneers. Ceramic veneers were cemented under rubber dam isolation to maximize bonding properties.

Conclusions: A single guide can be digitally designed and 3D printed to perform controlled gingivectomy and minimally invasive tooth preparations. The outcome of the gingivectomy improved the gingival architecture for central incisors, and the ceramic veneers fulfilled the patient's esthetic demands.

Objectives: This study investigated the effect of different surface treatments on the shear bond strength (SBS) and failure modes of self-cured (SC) and light-cured (LC) high-viscosity glass ionomer cements (HVGICs) to silver diamine fluoride (SDF)-treated simulated carious dentin (SCD).

Methods and materials: Extracted human premolars were sectioned and pH cycled for 10 days to simulate carious dentin. The demineralized specimens were treated with 38% SDF (Riva Star) for 2 minutes, washed, stored in deionized distilled water at 37°C for 2 weeks, and subjected to the following surface treatments (n=14): T1 - no treatment (control); T2 - 10 seconds polyacrylic acid (PAA); T3 - 5 seconds phosphoric acid (PPA); T4 - 5 seconds PPA plus universal adhesive (Zipbond); and T5 - 5 seconds PPA plus resin-modified GIC adhesive (Riva bond LC). SC (Riva Self-cure HV) and LC (Riva Light-cure HV) HVGICs were applied to the conditioned specimens and stored in artificial saliva at 37°C for 1 week. SBS and failure modes were subsequently determined. Statistical analyses were performed using Kruskal-Wallis/post-hoc Mann-Whitney U and Chi-square tests (α=0.05).

Results: The highest SBS was observed when SC and LC were restored with T2 and T5, respectively. Significant differences in SBS were as follows: SC - T2, T1 > T5, T3; LC - T5, T4, T3 > T2. SC generally exhibited adhesive failures, while LC presented both adhesive and mixed failures.

Conclusion: The preferred method for preparing SDF-treated carious dentin before restoration application is PAA for SC and PPA plus RMGIC adhesive for LC HVGICs.

Objectives: This study aimed to evaluate the impact of battery levels on the emission of a multi-peak cordless LED light-curing unit (LCU) and the effect on the degree of conversion (DC) and Knoop hardness (KH) of a light-cure resin luting agent activated through varying lithium disilicate (LiS2) ceramic thicknesses and translucencies.

Methods: High and low translucency LiS2 discs (IPS e.max Press HT and LT, respectively; shade A1) with thickness of 0.5, 1.0, 1.5, and 2.0 mm were fabricated. Resin luting agent specimens (Variolink Esthetic LC) were prepared and cured using a Bluephase G2 LCU at different battery levels (100%, 50%, and 10%) through the LiS2 ceramics. The transmitted irradiance was evaluated using USB4000 MARC, while FTIR and a microhardness tester assessed DC and KH, respectively. After ensuring homoscedasticity, the data wee analyzed using analysis of variance and Tukey HSD test (α=0.05).

Results: The study found strong positive correlations between battery levels and irradiance, particularly with no ceramic interposition and through HT ceramics (R2=0.9471), although this correlation diminished with thicker HT (R2=0.7907) and LT ceramics (R2<0.2980). Both battery levels and ceramic thickness significantly influenced transmitted irradiance (p<0.0001), resulting in lower values with decreased battery levels and increased ceramic thicknesses (p<0.0001). LT ceramics showed lower transmittance than HT. DC was significantly affected by both battery levels and ceramic thicknesses, with generally lower DC values except for LT ceramics at a 10% battery level (p<0.0001). No significant differences in DC were observed between HT and LT translucencies (p=0.548). KH was higher in HT than LT ceramics at 100% and 50% battery levels, with thicker ceramics showing lower KH values at 10% battery level (p<0.0001). Conclusion: Reduced battery levels in cordless LED curing units significantly affect the irradiance, degree of conversion, and hardness of light-curable resin luting agents. Maintaining battery levels above 50% is recommended for optimal performance. Thicker and more opaque ceramics significantly impacted incident irradiance. However, preserving radiant energy could potentially mitigate these limitations.

Objective: To evaluate surface roughness and bacterial adhesion after in situ biodegradation of the cementation interface of indirect restorations cemented with preheated resin composite.

Methods and materials: Resin composite blocks (Z250XT/3M ESPE) were cemented to bovine enamel (7 × 2.5 × 2 mm) using preheated microhybrid resin composites: (1) Filtek Z100 (3M ESPE) (Z100); (2) Gradia Direct X (GC America) (GDX); and (3) Light-cured resin cement RelyX Veneer (3M ESPE) (RXV) (n=21). The resin composites were preheated on a heating device (HotSet, Technolife) at 69°C for 30 minutes. Disk-shaped specimens (7 × 1.5 mm) were made for biodegradation analysis with the luting agents (n=25). The in situ phase consisted of 20 volunteers' using an intraoral palatal device for 7 days. Each device had six cylindrical wells for the blocks and the disk-shaped specimens. Biodegradation was evaluated through surface roughness (Ra), scanning electron microscopy (SEM) micromorphological analysis, and colony-forming unit (CFU) count. The film thickness of the luting agents was also measured under stereomicroscopy.

Results: Increased surface roughness was observed after the cariogenic challenge without differences between the luting agents. Higher variation and surface flaws suggestive of particulate detachment were observed for Z100. No differences were observed in CFU counts.

Conclusions: All materials underwent surface biodegradation, and the surface roughness of the resin cements was similar to or lower than that of the preheated resin composites. The resin composites' film thickness was thicker than that of the resin cement. Clinicians should be aware of these factors when choosing the use of preheated resin composite since it can lead to reduced longevity of the cementation interface and, therefore, restorations.

Objectives: This study aimed to evaluate the 18-month clinical performance of two different one-step adhesives that were applied alone or with an additional hydrophobic adhesive layer to noncarious cervical lesions.

Methods and materials: One hundred sixty teeth in 31 patients were included in the study. Each patient received at least four restorations. A 2-hydroxyethylmethacrylate (HEMA)-containing one-step self-etch adhesive (Clearfil S3 Bond Plus, Kuraray Noritake, Noritake, Japan) and a HEMA-free universal adhesive (G-Premio Bond) were applied to noncarious cervical lesions with or without additional hydrophobic adhesive (Heliobond) randomly. Teeth were restored with a nanohybrid composite. Restorations were evaluated according to FDI criteria at baseline, 6-, 12-, and 18-month recalls. Data were analyzed with the Kruskal-Wallis and the Friedman analysis of variance (ANOVA) tests (α=0.05).

Results: At 18 months, recall rates were 100%, and there was no significant difference between four different adhesive applications in terms of any criteria (p>0.05). The cumulative retention rates were 92.5%, 92.5%, 97.5%, and 100% for the restorations with one-step self-etch, one-step self-etch plus hydrophobic adhesive layer, a universal adhesive, and a universal adhesive plus hydrophobic adhesive layer, respectively.

Conclusion: An additional hydrophobic adhesive layer was found to have no significant effect on the 18-month clinical performance of two different one-step adhesive systems with and without HEMA.

Purpose: This clinical study aimed to evaluate the color measurement ability of intraoral scanners (Trios 3, (3Shape, Copenhagen, Denmark) and Cerec Omnicam, (Dentsply Sirona, Charlotte, NC, USA) in comparison to VITA Classical and VITA 3D-Master shades obtained by a spectrophotometer (Easyshade V, VITA, Zahnfabrik, Bad Säckingen, Germany).

Methods: Four hundred eighty teeth from thirty patients were included in the study. Fifteen patients had never undergone bleaching, and the other fifteen had undergone professional bleaching within the last 6 months. VITA Classical and VITA 3D Master shades were determined using Trios 3 (T3), Cerec Omnicam (CO), and EasyShade V from cervical, middle, and incisal/occlusal areas of maxillary and mandibular central and lateral incisors, canines, and first premolars. Color accuracy rates (cAR) were assessed by categorizing the color data according to the Munsell color system for bleached and unbleached teeth, maxillary and mandibular, and teeth arranged from anterior to posterior in each quadrant. McNemar, Mann-Whitney U, and Wilcoxon tests and Point Biserial Correlation Analysis were used for statistical analysis (significance level α=0.050).

Results: The bleached teeth had a significantly higher cAR for T3 in VITA 3D Master and VITA Classical guides (p<0.05). The cAR of the incisal area in VITA 3D Master was significantly lower in both scanners (p<0.05) except for the lightness/hue/chroma of bleached teeth. T3 cAR increased statistically significantly from anterior to posterior (p<0.001); however, no significant difference was found for CO (p=0.482).

Conclusion: The color accuracy rates of both scanners for shade guides that included all color components in this study were below 30%, which was not clinically satisfactory for color measurement. Confirming the measurements with a spectrophotometer is recommended.