Operative dentistry最新文献

Objectives: This study aimed to assess the surface roughness, surface free energy (SFE), and shear bond strength (SBS) on a lithium disilicate glass-ceramic surface following varying etching protocols (time variation) and application of silane either with or without adhesive material.

Methods and materials: Lithium disilicate glassceramic (LDGC) computer-aided design and computer-aided manufacture (CAD/CAM) blocks were cut using a slow-speed cutting mechanism. CAD/CAM blocks were then evaluated for surface roughness, 6 groups (n=20); SFE,12 groups (n=5); and SBS, 10 groups (n=10). The cut CAD/CAM blocks were randomly allocated to 28 groups. Groups were based on the following: 30 or 90 seconds of etching with 9% hydrofluoric acid (HF); application or absence of silane coupling agent (Sil); and application or absence of adhesive (Adh).The control group (Cont) had untreated surfaces. Unetched surfaces were surveyed with only silane (Sil), only adhesive (Adh), or silane+adhesive (SilAdh). Further etched groups were HF30 with HF for 30 seconds, HF30-Sil, HF30-Adh, and HF30-SilAdh. Alternative 90-second etching times produced similar groups: HF90, HF90-Sil, HF90-Adh, and HF90-SilAdh. A digital profilometer was used to assess the surface roughness of specimens, and two readings were recorded. Sessile drop analysis was used to examine SFE specimens, and the OWRK model was modified to measure liquid surface tension. A universal testing machine (UltraTester, Ultradent Products, Inc, South Jordan, UT, USA) was utilized for the SBS test, with the crosshead speed set at 0.5 mm/min until failure. Representative treated specimens from each group were submitted to surface morphological evaluation and chemical analysis using scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDXS) (n=3). After data collection, evaluation using one- or two-way analysis of variance and the post-hoc Tukey test (α=5%) was conducted.

Results: A longer etching time of 90 seconds produced a rougher surface. After the 90-second etching process, SFE displayed the greatest values; nevertheless, the use of silane did not affect SFE. For every group examined, the application of silane followed by adhesive resulted in an increase in SBS and more stable bonding over time. SEM/EDXS showed that etching times did affect the amount of cerium on the surface and altered surface morphology.

Conclusions: Higher and more consistent bond strengths have been observed with longer etching periods. Silane and adhesive application on the ceramic surface showed stronger and enhanced bond strength, specifically when longer etching times were employed.

Purpose: This study aimed to assess the impact of battery levels in single-peak and multi-peak light-curing units (LCUs) on irradiance, and their effects on glass fiber post push-out bond strength to root dentin and the degree of conversion of dual-cure universal resin cement.

Methods and materials: Sixty bovine roots underwent endodontic treatment and were randomly distributed into 6 groups (n=10), formed by combining two LCUs (single-peak and multipeak) and three battery levels (100%, 50%, and 10%). A spectrophotometer measured irradiance (mW/ cm2) and spectral irradiance (mW/cm2/nm). Push-out bond strength (PBS) tests occurred at three root regions (cervical, middle, and apical), with optical and scanning electron microscopy for failure mode analysis. Degree of conversion (DC) was evaluated across the root regions. Data were analyzed using two-way repeated measures ANOVA and the Tukey HSD test. The Fisher exact test verified failure modes (α=0.05).

Results: As multipeak LCU battery levels decreased, emitted irradiance also diminished, with notable PBS reductions in the apical thirds. Failure modes were influenced by different conditions, primarily exhibiting mixed modes. Battery levels significantly impacted DC in the multipeak LCU, particularly in the cervical region, while the single-peak LCU exhibited DC reduction at the 10% battery level in the cervical region.

Conclusions: Emitted irradiance, resin cement DC, and glass fiber post bond strength to root dentin may be influenced by varying cordless LCUs and battery levels.

Purpose: This study aimed to analyze the presence of defects within the adhesive interface formed with five bioactive dental materials and caries-affected dentin concerning the timing of radiotherapy (before or after the restorative procedures) by micro-CT.

Methods and materials: A total of 96 carious human molars were randomly allocated into the following groups based on the timing of the radiotherapy sequence: radiotherapy followed by restoration (RT1) or restoration followed by radiotherapy (RT2). Then, six subgroups were established within these groups based on the type of materials used (n=8). Following cavity preparation and caries removal, a universal adhesive (G-Premio Bond) was administered in self-etch mode or accompanied by applying suitable cavity conditioners according to the manufacturers' guidelines. Subsequently, restorations were performed using five bioactive restorative materials (resin-modified glass-ionomer [Fuji II LC], high-viscosity glass-ionomer hybrid [EQUIA Forte HT], giomer [Beautifil II], alkasite [Cention N], and dual-cure bulk-fill composite [Activa Bioactive Restorative]) and a conventional microhybrid resin composite (Filtek Z250). The radiotherapy regimen encompassed 60 Grays (Gy) administered at a rate of 2 Gy/day over 6 weeks, 5 days a week. Micro-CT analysis was employed to assess adhesive defects at the interface between caries-affected dentin and the restorations. The data were analyzed using Kruskal-Wallis, Mann-Whitney U, and Dunn tests (α=0.05).

Results: RT2 caused significantly higher adhesive defects than RT1 for the Filtek Z250 and Activa Bioactive Restorative subgroups (p<0.05). For RT1, no significant differences were found in adhesive defects among all tested subgroups (p>0.05). By contrast, for RT2, adhesive defects were significantly higher for the Activa Bioactive Restorative and Cention N subgroups than for the EQUIA Forte HT and Beautifil II subgroups (p<0.05).

Conclusions: When using most bioactive restorative materials, the timing of radiotherapy had no significant influence on the adhesive interface. Regarding restoration following a radiotherapy protocol, a favorable impact was identified with high-viscosity glass ionomer hybrid cement and giomer bioactive restorations compared with dual-cure bioactive bulk-fill composite and alkasite restorations.

Objectives: This study aimed to evaluate the influence of surface pretreatment on the shear bond strength (SBS) of a resin luting cement to enamel and dentin with saliva contamination. The surface free energies (SFE) of the adherent surfaces were also determined.

Methods and materials: Bovine enamel and dentin were used in this study. For the saliva-contamination, human saliva was applied to the adherent surface for 60 seconds and then air-dried, and the specimens without saliva contamination served as controls. One group of contaminated surfaces was untreated (SC), and the others were pretreated with Katana Cleaner (KC), Multi Etchant (ME), or Ultra-Etch (UE). Fifteen specimens were prepared to measure the SBS for each test group.The mixed resin luting cement paste was applied to the alumina-blasted surface of a stainless-steel rod and placed on the prepared tooth surface. The luting cement was light irradiated for 40 seconds. The bonded specimens were stored for 24 hours at 37°C and half of the bonded specimens underwent 10,000 thermal cycles. The SBS and SFE of the specimens after different pre-treatments were measured.

Results: The two-way ANOVA revealed that the factors of pretreatment agent and storage condition had a significant effect on the SBS to enamel and dentin. The SFE values of the SC group were significantly lower than those of the other groups in both enamel and dentin. The SFE of pretreated surface was material dependent.

Conclusions: A pretreatment agent containing functional monomers was shown to be effective in removing saliva contaminants and in creating an effective bonding surface for the resin luting cement.

Background: Various techniques, products, and protocols are used for the bleaching of non-vital teeth. The walking bleach technique involves sealing the bleaching agent in the pulp chamber. In the inside/outside technique, a low-concentration bleaching agent is applied at home using a custom tray. In the in-office technique, a high-concentration bleaching agent is applied by a dental professional. Limited research has compared the effectiveness of these techniques.

Objective: This clinical trial aimed to evaluate the effectiveness of the walking bleach, the inside/outside, and the in-office bleaching techniques.

Methods and materials: Fifty-four discolored teeth were selected according to eligibility criteria, randomized, and assigned to three treatment groups (n=18): walking bleach (sodium perborate - SP), inside/outside bleaching (7.5% hydrogen peroxide -HP7.5), and in-office bleaching (35% hydrogen peroxide - HP35). A cervical seal was placed in all the teeth, and nonvital bleaching was performed according to each technique. The CIELab color coordinates were measured using a clinical spectrophotometer at baseline, weekly, and at the 1-week follow-up. ΔE00 and ΔWID were calculated between the baseline and each evaluation time point. The ANOVA, Fisher exact, and Kruskal-Wallis tests were used to compare the quantitative variables, and the Fisher exact test, to determine the association among categorical variables. Bleaching effectiveness was interpreted by 50:50% perceptibility and acceptability thresholds.

Results: As the treatment progressed, all techniques presented a significant increase in L* and WID (p<0.001), and a significant decrease in a* and b* (p<0.001). HP7.5 and HP35 presented greater increases in WID mean values, in comparison with SP (p=0.006). No significant differences were observed among the techniques for ΔE00 after treatment completion (p=0.383). There were no statistical differences in bleaching effectiveness among the techniques after treatment completion (p=0.098).

Conclusion: All techniques presented excellent effectiveness after treatment completion. However, HP7.5 and HP35 techniques provided a more rapid whitening response.

Objective: Evaluate the impact of adjustment procedures - cut-out-rescan (COR) and data exchange by over-scanning (DEOS) techniques - through CAD/CAM software on the marginal fit outcome of ceramic crowns.

Methods and materials: Twenty-eight de-identified teeth were adapted in a mandibular typodont set. Tooth #19 was prepared for a lithium disilicate crown and seven groups, G0 to G6 (n=10), were created based on the rescanned areas (mesial and/or buccal) on the typodont using an intraoral scanner through COR or DEOS techniques. A digital workflow was used to design and mill 70 crowns according to the groups. Each crown was temporarily cemented on tooth #19 and scanned with micro-computed tomography to measure the marginal fit. The data were analyzed statistically by the Kruskal-Wallis test followed by the Mann-Whitney test to compare the groups pairwise as a post-hoc (α=0.05).

Results: Statistically significant differences were found for vertical misfit (μm) between the groups for Marginal Gap Buccal (MGB) and Marginal Gap Mesial (MGM) (p=0.003 and p=0.029, respectively). No significant difference was found for Finish Line Buccal (FLB) and Finish Line Mesial (FLM) (p=0.062 and p=0.092, respectively). G3 (COR buccal and mesial) had the highest MGB (57.75 μm), statistically different from all other groups. G4 (DEOS buccal) (41.60 μm) was different from G6 (DEOS buccal and mesial) (44.21 μm) (p=0.023). For MGM, G0 (control) (53.96 μm) was different from G5 (DEOS mesial) (45.76 μm) and G6 (DEOS buccal and mesial) (48.56 vm) (p=0.013 and p=0.041, respectively) and G2 (COR mesial) (58.43 μm) was different from G5 (DEOS mesial) (45.76 μm) (p=0.016).

Conclusions: Despite a statistically significant difference in certain groups for both techniques, COR and DEOS techniques are viable options for image editing during acquisition. Lithium disilicate crowns can be produced with satisfactory marginal gap values utilizing a chairside CAD/CAM system.

Objective: To evaluate the shade-matching ability of single-shade resin-based composite restorations in different thicknesses using both instrumental and visual techniques.

Methods and materials: Cavities with 4 mm diameter and 2 mm (n=96) or 3 mm (n=96) depth were prepared in acrylic incisor teeth of shades A2, A3, B3, and C2 and restored with three single-shade resin composites, Omnichroma (Tokuyama Dental America, Encinitas, CA, USA [OM]), Vittra APS Unique (FGM Dental Group, Joinville, SC, Brazil [VU]), Zenchroma (President Dental, Allershausen, Germany [ZC]), and a microhybrid resin composite (Filtek 3M Z250 3M ESPE, St Paul, MN, USA [FZ]) of A2, A3, B3, and C2 shades. Readings were obtained using VITA Easyshade V spectrophotometer for the teeth and restorations. The CIEDE2000 (ΔE00) color difference formula was used, and the values were assessed using three-way analysis of variance (ANOVA). Forty-eight evaluators graded the shade match of 32 different specimens visually as (A) best shade match, (B) intermediate shade match, and (C) poor shade match.

Results: FZ material achieved satisfactory matches for both thicknesses, across all shades, and OM material demonstrated statistically significant lower shade matches than the ZC and the FZ materials (p<0.05). VU exhibited poor shade match with the highest ΔE00 value on C2 shade. According to the visual examination, the best shade matches were observed for FZ on A3-shade and ZC on C2-shade teeth.

Conclusions: Shade matching for 2 mm and 3 mm-thick composite resin restorations is material- and tooth-shade dependent.

Aim: This systematic review and meta-analysis evaluated theobromine's (Theobroma cacao) potential in remineralizing white spot lesions in dental enamel. Methods: This study is reported according to the PRISMA checklist and was registered in PROSPERO (CRD42023414371). In vitro tests that evaluated the remineralizing potential of theobromine compared to fluoride ion after demineralization for the formation of white spot lesions on enamel were selected, with no limitation on the year of publication. Electronic searches were performed in PubMed/MEDLINE, Scopus, and Web of Science by two independent researchers. Thirty articles were received of which six were selected according to the inclusion criteria.

Results: The selected studies evaluated the Enamel Surface Microhardness (SMH), Vickers or Knoop, before and after treatment with theobromine and fluoride solutions. For the SMH Vickers, there were no differences between groups at baseline (p=1.00; mean difference: -0.00; CI: -11.36 to 11.36) and after treatment (p=0.51; mean difference: 4.12; CI: -8.16 to 16.41). The results of SMH Knoop showed differences between groups at baseline, favoring the experimental group (p=0.002; mean difference: 9.84; CI: 3.65 to 16.02) and after treatment favoring the control group (p=0.00001; mean difference: -5.45; CI: -7.62 to -3.27).

Conclusion: The use of theobromine increases the microhardness of dental enamel subjected to a demineralization process, thus being effective in the remineralization of this tissue with success equivalent to that obtained with the use of fluoride.

Background: Marginal adaptation and retention of endocrowns are crucial for the success and survival of endocrowns. This study aimed to investigate the effect of different materials and intracoronal depth on the retention and marginal adaptation of CAD/CAM fabricated all-ceramic endocrowns.

Methods: Thirty-six mandibular premolar teeth with an average surface area of 64.49 mm2 were prepared to receive CAM/CAM fabricated endocrowns. Samples were divided randomly and equally into groups of lithium disilicate with 2 mm intracoronal depth (LD2), lithium disilicate with 4 mm intracoronal depth (LD4), polymer infiltrated ceramic network with 2 mm intracoronal depth (PICN2) and polymer infiltrated ceramic network with 4 mm intracoronal depth (PICN4). All endocrowns were cemented using ParaCore resin cement with 14N pressure and cured for 20 seconds. Fifty measurements of absolute marginal discrepancy (AMD) were done using a stereomicroscope after cementation. After 24 hours, all samples were subjected to thermocycling before the retention test. This involved using a universal testing machine with a crosshead speed of 0.5 mm/min and applying a load of 500N. The maximum force to detach the crown was recorded in newtons and the mode of failure was identified.

Results: Two-way ANOVA revealed that the AMD for PICN was statistically significantly better than lithium disilicate (p=0.01). No statistically significant difference was detected in the AMD between the two intracoronal depths (p=0.72). PICN and endocrowns with 4 mm intracoronal depth had statistically significant better retention (p<0.05). 72.22% of the sample suffered from cohesive failures and 10 LD endocrowns suffered adhesive failures.

Conclusions: Within the limitations of this study, we found that different materials and intracoronal depths can indeed influence the retention of CAD/CAM fabricated endocrowns. Based on the controlled setting findings, PICN was found to have better retention and better marginal adaptation than similar lithium disilicate premolar endocrowns.