Operative dentistry最新文献

This study investigated the color stability and surface roughness of universal chromatic resin-based composites (RBCs) after immersion in detox juices. One hundred seventy-six disc-shaped specimens (8 mm in diameter and 2 mm in thickness) were prepared using four universal chromatic RBCs: NeoSpectra ST (NS), Omnichroma (OM), Charisma Topaz One (CO), and G-ænial Universal Injectable (GI). Specimens of each material were randomly divided into four subgroups (n=11) and immersed in either the assigned detox juices (red, green, or yellow) or distilled water (control). Color and surface roughness measurements were taken at baseline, 15 and 30 days of immersion. Scanning electron microscopy (SEM) was used to evaluate the surface topography of the composites. The color change [CIEDE2000 (ΔE00)] and surface roughness (Ra) values were analyzed using generalized linear models and multiple comparison tests with Bonferroni correction. Correlation analysis was performed using Spearman rank correlation test. The main variable effects of "composite and immersion media" were significant for both color change and surface roughness parameters (p<0.001). Additionally, the main effect of the "evaluation period" was significant only for surface roughness (p=0.001). The highest discoloration occurred in the GI group immersed in a red beverage, while the CO group immersed in yellow beverage had the highest Ra values. In SEM analysis, OM demonstrated a more homogeneous filler structure with clearly visible nano-spherical fillers and nanoclusters, contributing to its superior smoothness. Conversely, a significant increase in rough areas was observed, especially in NS exposed to the green beverage and CO exposed to the yellow beverage, after 30 days. While the immersion of resin composites in detox juices induced an acceptable color alteration except for OM and GI groups immersed in the red beverage, all tested materials exhibited clinically admissible results regarding surface roughness.

Objective: This study evaluated the influence of two types of glass ionomer-based luting agent on the clinical performance of metal-free zirconia crowns.

Methods and materials: Thirty participants received two full crown restorations in either anterior or posterior teeth, in a split-mouth design. After tooth preparation, impressions with addition-cured silicone were made and casts were obtained. The casts were scanned and 3Y-TZP zirconia copings (Ceramill ZI - Amann Girrbach) were milled using a CAD/CAM system. Glass ceramic (IPS E.max Ceram, Ivoclar Vivadent) was used to create the crown shape. For each participant, one crown was cemented using a conventional glass ionomer (GIC - Meron, Voco), while the other received a resin-modified glass ionomer cement (RMGIC - Meron Plus QM, Voco). The restorations were evaluated by two calibrated examiners after seven days, one year, and two years. The parameters at each evaluated time were analyzed by the Fisher exact test (α=0.05).

Results: At two years postoperatively, 24 participants attended the recall, and 46 (76.67%) restorations were evaluated. No fractures or secondary caries were diagnosed. Minimal marginal staining was verified in both cements. During the follow-up period, only two anterior crowns cemented with conventional glass ionomer showed loss of retention. No loss of retention was detected in posterior crowns.

Conclusion: After two years of intraoral service, the crowns cemented with either conventional glass ionomer cement or resin-modified glass ionomer presented acceptable and similar clinical performance for all parameters analyzed in both anterior and posterior teeth.

Objectives: The purpose of this study was to compare the curing light transmittance and depth of cure (DOC) of resin composite through clear polyvinyl siloxane (PVS) impression materials and 3D printed clear matrix materials at various thicknesses.

Methods and materials: Cylindrical specimens (n=6) of three clear PVS materials (Affinity Crystal, Clear Bite Matrix, Exaclear) were fabricated in Teflon molds, and two 3D-printed clear matrix materials (Filtek matrix, IDB 2) were printed into specimens of five different thicknesses (2 mm, 4 mm, 6 mm, 8 mm, 10 mm). To measure light irradiance transmittance, specimens were placed on a radiometer (CheckUp), allowing the transmitted irradiance from a light-curing unit (Elipar DeepCure-S, 1450 mW/cm²) to be recorded. DOC of resin composite specimens was measured by placing flowable composite (PVS and IDB 2) or heated conventional composite (Filtek Matrix) into a split metal die with a 4 mm diameter opening. The composite was cured through the different matrix specimens using the Elipar DeepCure-S curing light for the manufacturer's recommended curing time (10 seconds) or double the curing time (20 seconds). The DOC of the composite specimens was measured according to ISO 4049 7.8, and the percentage of total cure (%TC) was calculated by dividing by the total cure (DOC with no matrix and 10-second cure). The correlation between irradiance transmittance and %TC was analyzed with Pearson's coefficient. For each matrix material, the %TC was compared to the total cure of the material using a Dunnett's test. The compressive modulus of each material was measured and compared with a one-way ANOVA.

Results: There was a statistically significant, strong positive correlation between irradiance transmittance and %TC for 10 seconds (r=0.90 p<0.001) and 20 seconds (r=0.89 p<0.001). There was not a statistically different DOC for the total cure with Affinity (2 mm), Clear Bite (2 mm), Exaclear (2, 4, 6 mm), IDB2 (2, 4, 6, 8 mm), and Filtek Matrix (2,4 mm) if a 20-second cure was used.

Conclusions: Decreased light irradiance from curing through clear matrix materials decreases the DOC of resin composites. Doubling the curing time when curing through some matrix materials at certain thicknesses allowed a total cure.

The aim of this study was to investigate whether different concentrations of acacia extract could improve the biological stability of dentin collagen. Slice (n=3) and beam (n=5) samples of dentin obtained from human third molars were demineralized and treated with the following solutions: G1 (control)-deionized water; G2-1% acacia extract; G3-2% acacia extract; and G4-3% acacia extract. The dentin slices were analyzed by Fourier transform infrared (FTIR) spectrophotometry to observe their interactions with collagen. The beams were submitted to digestion with type I bacterial collagenase solution, and the percentage of weight was calculated to evaluate the resistance to enzymatic biodegradation. The Adper Scotchbond Multipurpose adhesive system was applied on the flat dentin surfaces according to the manufacturer's recommendations (G1). In groups G2, G3 and G4, acacia extract at concentrations of 1%, 2%, and 3%, respectively, were applied after acid etching. A resin composite block was built on the adhesive, and the teeth were cut to obtain beams (n=7 teeth; ~12 beams per tooth) with cross-sectional areas of approximately 0.8 mm2. Half of the specimens were submitted to the microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min, and the other half were submitted to the µTBS test after six months of storage in distilled water. FTIR analysis showed the interactions of the three concentrations of acacia extract with collagen. According to ANOVA and Tukey tests, G1 had the highest biodegradation rate (100%), which was significantly higher than the rates of G2 (24%), G3 (23%) and G4 (17%) (p<0.05). According to two-way ANOVA and Tukey tests, only G1 showed a significant decrease in µTBS after six months of storage (p<0.05). It was concluded that 1%, 2%, and 3% acacia extract all interacted with human dentin collagen, reduced collagen biodegradation and favored the stabilization of the bonding interface at the six-month evaluation.

The aim of this this study was to evaluate the surface roughness and color stability of resin composites (RCs) with color adjustment potential (CAP): Omnichroma (OM), (Tokuyama Dental, Tokyo, Japan); Neo Spectra ST (NS) (Dentsply Sirona, York, PA,USA); and Charisma Diamond One (CD) (Kulzer, Hanau, Germany), compared to a conventional RC, Filtek Z350XT (FZ) (3M ESPE, St. Paul, MN,USA), after immersion in three staining solutions, cola, coffee, and black tea, with distilled water as a control. Forty specimens (8 mm diameter x 2 mm thickness) were prepared for each RC material and divided into subgroups (n=10/group) based on the immersion solution. Surface roughness was measured at baseline and after 21 days of immersion using a non-contact optical profilometer. Color change (ΔE00) was evaluated at baseline, 1, 7, and 21 days with a spectrophotometer. The results showed that FZ demonstrated the lowest surface roughness (0.14), significantly differing from that of the other RCs with CAP (p<0.05), while no significant differences in surface roughness were observed between RCs with CAP (p>0.05). There were no significant changes in surface roughness before and after immersion in various solutions. The results for color change (ΔE00) were statistically significant. Neo Spectra ST showed the lowest tendency for color change, while Filtek Z350XT displayed a moderate potential, and Omnichroma and Charisma Diamond One showed the highest potential for color change.

Objective: Systematic review and meta-analysis on laboratory studies aimed to answer whether there is a difference in fracture resistance and fracture mode of structurally compromised teeth restored with direct composite restorations reinforced with short glass-fiber or bidirectional polyethylene fiber substructure, and between the two different fiber-reinforcement types.

Methods: An electronic literature search was conducted in Medline, Scopus, Web of Science, Lilacs, Google Scholar, Cochrane Library, and University Library databases. The last search was conducted on 16 November 2023. Only studies looking at Ribbond-reinforced restorations and/ or the use of EverX Posterior within restorations were included. Data were categorized and analyzed based on specific outcome measures including fracture resistance and fracture mode. Data from individual studies were divided into premolars and molars for each material category and then collated to compare the mean differences in fracture resistance between control groups (composite restorations) and intervention groups (fiber-reinforced composite restorations).

Results: From the initial 1266 articles identified, 23 laboratory-based studies were included for quantitative analysis. Twenty articles had an overall low risk of bias and 3 had an overall unclear risk of bias. The pooled estimate of the effect favored the intervention groups as having statistically significant higher fracture resistance when compared to control groups.

Conclusions: Both fiber types improve fracture resistance and the fracture mode of structurally compromised teeth is equally efficient. Application technique deserves attention. Ribbond could be placed in a single layer at the cavity floor, whereas EverX Posterior should replace missing dentin in an anatomically shaped way.

Introduction: The aim of this study was to evaluate the effects of fluoride-containing remineralization agents on enamel white spot lesions.

Methods and materials: Twenty bovine incisors were cut mesio-distally and occluso-gingivally, creating 80 specimens, and divided into four groups (n=20/group): 1) control (no treatment); 2) fluoride varnish (Voco Profluoroid 5% NaF Varnish, VOCO Dental, Cuxhaven, Germany); 3) CPP-ACFP (MI Paste Plus with Recaldent, GC Corporation, Tokyo, Japan),; 4) self-assembling peptide (P11-4F, CURODONT Repair Fluoride Plus, Credentis AG, Windisch, Switzerland). After a three-week demineralization-remineralization cycle, white spot lesions were observed on the specimens. Before applying the remineralization agents, baseline demineralization values were determined using DIAGNOdent 2095, QLF-D Biluminator, SEM-EDS (KaVo Dental, Charlotte, NC, USA), and color values were measured by Vita EasyShade (Vita Zahnfabrik, Bad Säckingen, Germany). Remineralization agents were applied once, following the manufacturers' instructions. The remineralization capacities of these agents and their effects on color change were evaluated at four time points: baseline (T0), demineralization (T1), and remineralization on the seventh (T2) and 30th (T3) days.

Results: After 30 days, CPP-ACFP and P11-4F showed significantly greater Ca (% by weight), F (% by weight), and Ca/P ratio than the fluoride varnish group (p<0.05). SEM images revealed that in the groups where the remineralization agent was applied, the pores and tubules were blocked, and the surfaces were covered, whereas these findings were not observed in the control group. Based on QLF-D Biluminator data, P11-4F application provided more successful fluorescence changes compared to CPP-ACFP and fluoride applications and was statistically more effective in reducing lesion volume and maximum fluorescence loss (p<0.05). Significant differences were observed among the four groups at the seventh (T2) and 30th days (T3) in the laser fluorescence evaluation with DIAGNOdent (p<0.05). On the seventh day, the fluoride group exhibited greater effectiveness than the control group, while on the 30th day, the CPPACFP group demonstrated superior improvement over the control group (p<0.05). According to color change results, applying a remineralization agent was found to be a statistically successful method in restoring the tooth's original color (p<0.05). However, there were no significant differences among the treatment groups (p>0.05).

Conclusions: CPP-ACFP and P11-4F demonstrated positive effects on remineralization at the seventh and 30th days. Applying a remineralization agent is a viable option for blocking pores and tubules on demineralized enamel. The color change related to the use of the remineralization agent showed a positive effect over time.

Objective: This study aimed to assess the fracture resistance of chairside computer assisted design and computer assisted manufacturing (CAD-CAM) lithium disilicate partial and full-coverage crowns and veneers for maxillary canines.

Methods and materials: Forty-eight restorations for maxillary right canines (12 per group) were designed as follows: (1) partial crown with finish line in the upper middle third; (2) partial crown with finish line in the lower middle third; (3) traditional labial veneer; and (4) traditional full-coverage crown. Restorations were fabricated out of lithium disilicate (Amber Mill, Hassbio) using a chairside CAD-CAM system (Cerec Dentsply Sirona). Partial and full crowns and veneers were treated with a primer system (Monobond Plus, Ivoclar Vivadent) and cemented using dual-cure resin cement (Variolink Esthetic, Ivoclar Vivadent) and cemented to printed resin dies. Subsequently, the restorations were subjected to 10,000 thermocycles between 5°C and 55°C with a dwell time of 30 seconds. The restorations were then loaded axially on the incisal edge in compression to fracture with a flat indenter.

Results: Full-coverage crowns displayed the highest fracture resistance (809±28.57 N) followed by partial crowns with finish line in lower third (649±21.74 N) and crowns with finish line in upper third (421±17.46 N). Veneers displayed the lowest fracture resistance values (259±15.69 N).

Conclusions: The fracture resistance of partial and full-coverage crowns and veneers was significantly influenced by the design. Full coverage crowns displayed the highest fracture resistance and partial crowns showed higher fracture resistance than traditional veneers.