American journal of dentistry最新文献

Purpose: To evaluate the impact of different surface cleaning methods and immediate dentin sealing (IDS) on the bond strength of a universal adhesive resin cement to dentin, using a 3D-printed restorative material.

Methods: Extracted human third molars were prepared and divided into two groups: with and without IDS. Temporary restorations were cemented onto the prepared tooth surfaces. Five surface cleaning methods were applied to both groups: pumice, pumice with soap, sandblasting, EDTA, and laser. 3D printed resin blocks were fabricated and bonded to the teeth using a universal adhesive resin cement. After thermal cycling and water storage, microtensile bond strength tests were conducted. Failure modes were analyzed using light microscopy and SEM. Statistical analyses were made.

Results: Microtensile bond strength (µTBS) was significantly influenced by both surface cleaning methods and IDS application. Sandblasting and laser cleaning resulted in the highest µTBS values, particularly when combined with IDS. IDS significantly increased µTBS compared to the control group, regardless of the cleaning method. SEM analysis revealed that adhesive failure was the predominant failure mode in most groups, with some mixed failures observed.

Clinical significance: Prepared tooth surface cleaning procedures increased the microtensile bond strength of the universal adhesive resin cement regardless of immediate dentin sealing.

Purpose: This single-center, single-treatment, 4-week study evaluated the efficacy of a stannous fluoride (SnF₂) dentifrice in reducing peri-implant mucositis while assessing changes in biomarkers and the oral microbiome profile.

Methods: 24 healthy participants 18 years of age or older with osseointegrated implants were included, with 19 participants having mucositis and five without mucositis. The non-mucositis participants served as a reference group for microbiome and biomarker assessments (baseline comparison). All participants used the same 0.454% SnF₂ dentifrice (Crest Pro-Health Sensitive and Enamel Shield) and a soft manual toothbrush twice daily throughout the study. Participants received Modified Gingival Index (MGI) and Gingival Bleeding Index (GBI) assessments at Baseline - Day 1 and at Week 4 - Day 1. Subgingival plaque and peri-implant crevicular fluid (PICF) were collected on Baseline - Day 2 and Week 4 - Day 2 for oxidative stress markers, bacterial endotoxins, proinflammatory cytokines and 16S analysis.

Results: After 4 weeks, participants with mucositis experienced a significant reduction from baseline in MGI and GBI scores (63.4% and 79.3%, respectively) and in the number of bleeding sites (72.5% based on GBI analysis). Microbiome analysis of subgingival plaque showed that mucositis was associated with a higher relative abundance of disease-associated genera (Fusobacterium, Porphyromonas, Treponema, and Prevotella) and a lower relative abundance of commensal genera (Rothia and Actinomyces). Alpha diversity was higher in the mucositis group compared to the non-mucositis group at baseline. By Week 4, the profile of participants with mucositis had shifted to align more closely with that of non-mucositis participants. Participants with mucositis showed significant reduction in biomarkers related to bacterial insult, plaque virulence, oxidative stress, and inflammation. Simulated pathway and process analysis revealed that multiple categories of genes were associated with a state of mucositis, and 4 weeks of use of the experimental dentifrice downregulated several virulence-associated genes.

Clinical significance: In participants with mucositis, use of a SnF₂ dentifrice for 4 weeks reduced clinical signs and key biomarkers of peri-implant inflammation and shifted the oral microbiome toward a healthier profile, highlighting the utility of SnF₂ dentifrice in the control of peri-implant mucositis.

Purpose: To evaluate the impact of different instruments on dental implants on titanium discs and simultaneously test how effective they were in removing calculus.

Methods: Artificial calculus was applied on 36 rectangular areas demarcated on titanium discs. Surface roughness was measured using a stylus profilometer. Calculus was then removed using six different hand or power-driven ultrasonic instruments. Surface roughness measurements D-Ra and D-Rz were then re-calculated. Cleaned distance was divided by total calculus to yield a cleaning ratio and the number of cleaning strokes required to remove the calculus was calculated. All measurements were statistically analyzed independently (two-way ANOVA, Holm-Sidak roughness and cleaning ratios Kruskal-Wallis one-way ANOVA on ranks, and Student-Newman-Keuls, α< 0.05).

Results: Ultrasonic magnetostrictive instruments were most efficient in calculus removal and demonstrated a statistically high cleaning ratio percentage (P< 0.001) and required the least number of strokes compared to all the other groups. The resin curettes were the least effective in calculus removal and required the greatest number of strokes. When surface roughness values (D-Ra) were compared between different instruments, statistically significant differences were noted between the resin curettes and ultrasonic magnetostrictive groups, with the resin curette group showing lower values and the Ultrasonic magnetostrictive group showing greater values.

Clinical significance: Current research on significance of titanium particles and their possible role in causing periimplantitis emphasizes the importance of using instruments that do not damage the implant surface. Instrumentation causing the least amount of surface roughness should be considered since the risk of damaging the surface outweighs the benefit.

Purpose: To evaluate the laboratory microtensile bond strength (µTBS) of universal adhesives applied in etch-and-rinse mode on irradiated and sound human dentin.

Methods: Dentin specimens of 135 freshly extracted human third molars were divided in three superordinate groups. Each tooth received either no irradiation (control group), 5 Gy (2 Gy/2 Gy/1 Gy in 3 consecutive days) or the high-level therapeutic dose of 60 Gy (test groups) applied fractionally (2 Gy/day, 5 days/week, 6 weeks). Samples from each group were randomly divided into three subgroups assigned to three established universal adhesives (Futurabond U, AdheSE Universal, Xeno Select) in just the etch-and-rinse application mode (n= 15). Bond strength was assessed with a universal testing machine 15 minutes after application and light curing of the adhesive materials. Statistical analysis was performed using a two-way ANOVA (P< 0.01) and Tukey's test (P< 0.05).

Results: Regarding all experimental groups ANOVA showed significant effects on µTBS of dentin irradiation and the used adhesives (P< 0.01, ANOVA). In nearly all groups, a decrease of µTBS was observed when used on highly irradiated dentin. However, comparing the different groups, no significant influence of high-level radiation on the microtensile bond strength of the three universal adhesives assessed in etch-and-rinse application mode could be determined (P> 0.05, Tukey's test).

Clinical significance: Within the limitations of this laboratory study, no significant effects of low- and high-level tumor irradiation on the bond strength of universal adhesives can be detected after application in etch-and-rinse mode. Consequently, this mode of application may be considered a viable option for patients who have undergone radiation therapy when using universal adhesive systems for luting restorative materials.

Purpose: To investigate the shear bond strength of different primers with adhesive cements to 3D printed restorations.

Methods: 72 3D-printed restorations (Formlabs permanent crown resin) and nano-hybrid composite (Tetric EvoCeram) resin cylinders prepared and assigned to two groups, according to G-Multi Primer (GMP) with G-Cem One (GCO) and Clearfil ceramic primer plus (CCP) with Panavia F2.0 (PF) cements and three subgroups (n=9) were created for each cement: (1) control group, (2) 5,000 thermal cycles, (3) 10,000 thermal cycles. 3D-printed restorations were embedded in Teflon molds and cemented with nano-hybrid composite resin cylinders and a shear bond strength test was performed according to group. Failure modes were observed with stereomicroscope (30x), and surface morphology was evaluated with SEM analysis (100x and 2,000x). Statistical analysis was performed using Kolmogorov-Smirnov and Shapiro Wilks tests, and for evaluating the study data, 2-way ANOVA test and post hoc Tukey HSD test were used.

Results: The GCO groups exhibited significantly higher SBS values than the PF groups in the bonding of the tested 3D-printed restorations. There was no statistically significant difference in the bond strengths of tested GCO cement groups. A control group of PF cement showed significantly higher SBS values than the 5,000 and 10,000 cycling of PF groups. However, there was no statistically significant difference in the 5,000 and 10,000 cycling PF groups. The bonding performance was superior for the GCO group.

Clinical significance: This study showed that exposure to gutta-percha solvents (chloroform, orange oil and Endosolv) for 5 minutes did not affect the bond strengths of both iRoot SP (bioceramic sealer) and AH Plus (resin sealer) to root dentin.

Purpose: To systematically evaluate the effect of bisphosphonates on periodontal diseases in menopausal and postmenopausal women.

Methods: Databases (PubMed, Embase, Web of Science, Cochrane Library databases, Chinese Scientific and Technological Journal database, Wan Fang Data, China Biomedical Literature Database, and Chinese National Knowledge Infrastructure) were searched from inception to July 2024, languages are Chinese and English. Randomized controlled trials (RCTs) reporting the effect of bisphosphonates in menopausal and postmenopausal women with periodontitis were included. The risk of bias was performed using the Cochrane collaboration tool. The primary outcome was clinical attachment loss (CAL), and the secondary outcomes were probing depth (PD) and gingival index (GI). The analysis of the data was performed using Rev Man 5.3 and Stata 16.0.

Results: The meta-analysis incorporated four studies that fulfilled the inclusion criteria. In evaluating the efficacy of bisphosphonates against control treatments, there was high heterogeneity observed in CAL (P = 0.0002; I² = 85%) and PD (P< 0.00001; I² = 93%) within the study groups. Meta-analysis showed a significant improvement in CAL gain (MD = - 0.57 mm; 95% CI = -1.04 to -0.11 mm; P< 0.05), PD reduction (MD = - 0.50 mm; 95% CI = -0.96 to -0.05 mm; P< 0.05), and GI reduction (MD = -1.11; 95% CI = -1.22 to -1.01; P< 0.00001) for bisphosphonate treatment vs. bisphosphonate-naïve therapy.

Clinical significance: Bisphosphonate treatment seems to be beneficial for managing periodontitis in menopausal and postmenopausal women.

Purpose: To evaluate the effect of toothpaste containing sodium fluoride, a commercially available remineralization product, on the microhardness and roughness of enamel after whitening with two different concentrations of hydrogen peroxide.

Methods: 32 premolar teeth extracted for orthodontic reasons were collected. Initial microhardness and roughness values were measured. All samples were immersed in a coffee solution for 1 week to simulate coloration in the oral environment and ensure standardization. Then, the second microhardness and roughness measurements were obtained. Two samples were separated, and the remaining ones were divided into three groups; Group 1: Group 2: Samples treated with Beka HP 30% bleaching agent; Group 3: Samples kept in distilled water. For Groups 1 and 2, the bleaching procedure was applied in three sessions of 15 minutes each, following the manufacturer's instructions. Afterward, measurements of all samples were repeated. To examine the reversibility of surface changes following the bleaching process, a demineralization-remineralization (pH) cycle was applied. Subsequently, microhardness and roughness measurements were repeated, and two samples from each group were set aside for FE-SEM Field emission scanning electron microscope analysis. A total of eight samples underwent FE-SEM analysis at x1,000 and x5,000 magnifications. Data were analyzed using two-way ANOVA and Kruskal-Wallis tests.

Results: Initial microhardness values of all samples were the highest values, with a decrease observed after the bleaching procedure. Even though the microhardness of the samples increased in Groups 1 and 2 after the pH cycle, there was no significant difference (P< 0.05). While the roughness values of the samples decreased after the discoloration (P> 0.05), they increased after the pH cycle and there were significant differences between the 4th measurement and the other measurements (P< 0.05).

Clinical significance: The bleaching agent causes changes in the structure of the enamel and reduces microhardness and roughness values. However, remineralizing agents applied during the pH cycle may have a positive effect on microhardness.

Purpose: To assess if amino acid-based carbon dots (CDs) eliminate in vitro cancer cells.

Methods: CDs were synthesized using cysteine as a precursor and metal and photosensitizer as modifiers. In vitro cell viability tests were performed using cancer and normal cells without and with H₂O₂ and laser irradiation. Methylene blue (MB) solution was used to evaluate the production of ROS by CDs via observing absorbance differences before and after treatments. Extracellular oxygen production was measured in real-time using a probe. The generation of singlet oxygen was spectroscopically evaluated using RNO-ID assay.

Results: Within the test conditions, CDs fn-Cei-Ce6 achieved significantly low in vitro cancer cell viability (near to 26% of initial cell count) at 20 ppm concentration, high absorbance difference (Δ) in all wavelengths, oxygen production approximately to 1.2 mg/L, and high absorbance decrease of RNO-ID assay solution all with 100 µM H₂O₂ and laser irradiation conditions.

Clinical significance: Amino acid-based carbon dots (CDs) eliminated cancer cells in vitro with near to 74% of initial cancer cells under 100 µM H₂O₂ and laser irradiation conditions. The results may be extended to the clinical potential of fn-Cei-Ce6 in treating tumors in the oral cavity.

Purpose: To assess the relative efficacy of a new entry-tier oscillating-rotating (OR) electric toothbrush versus a sonic electric toothbrush over 4 weeks of use for plaque and gingivitis reduction.

Methods: This single-center, examiner-blind, two-treatment, parallel-group, randomized clinical study enrolled adult participants who had evidence of gingivitis and plaque at baseline. Participants were randomly assigned to use either an entry-tier OR toothbrush (Oral-B iO2) with the Ultimate Clean brush head in Daily Clean mode or an advanced sonic toothbrush (usmile Marble-Art) used with the usmile Advanced Whitening brush head in Clean mode (and at the high-intensity level). Both groups brushed with a standard sodium fluoride dentifrice. Participants were assessed for gingivitis (Modified Gingival Index and the Gingival Bleeding Index) and plaque (Rustogi Modification of the Navy Plaque Index) at baseline and after 4 weeks of twice-daily use. Plaque was also assessed after a single use at baseline.

Results: Both toothbrushes statistically significantly reduced gingivitis after 4 weeks of use and plaque after a single use and after 4 weeks (P< 0.001 for all). The OR toothbrush, relative to the sonic toothbrush, demonstrated a statistically significantly greater reduction in Modified Gingival Index score and number of bleeding sites (P< 0.001) and was associated with a significantly greater number of users transitioning from gingivitis to a state of gingival health (i.e., < 10% bleeding sites; P= 0.038) by the end of the study. The OR toothbrush likewise demonstrated greater efficacy with respect to plaque reduction after a single use (whole mouth, interproximal, and gingival margin; P< 0.001 for all) and after 4 weeks of use (whole mouth and interproximal; P< 0.001 for both).

Clinical significance: The novel entry-tier OR toothbrush offers significantly greater plaque control and gingivitis reduction relative to the advanced sonic toothbrush model.

Purpose: To evaluate the surface roughness (SR) and surface topography (ST) of mechanical brushing with pure-unfilled PEEK (U-PEEK) and PEEK materials with different contents [titanium-containing PEEK (T-PEEK), ceramic-modified PEEK (C-PEEK) and glass fiber-reinforced PEEK (G-PEEK)].

Methods: A total of 40 disc-shaped samples (10 mm x 2 mm) were obtained (n= 10) from each group (U-PEEK, T-PEEK, C-PEEK, G-PEEK). After sanding and polishing, a profilometer was used to analyze all discs' surface roughness (Ra). Qualitative analysis (QA) was performed on random samples with the help of a scanning electron microscope (SEM). Brushing was done with a custom-made brushing simulator, and the analyses were repeated. Statistical analysis was performed (P< 0.05).

Results: A statistically significant difference was found between the PEEK groups before and after brushing (P< 0.05). In the measurements before and after brushing, the lowest measurement value was seen in the C-PEEK and T-PEEK groups. While there was no significant difference between T-PEEK and C-PEEK measurements, both measurements found the highest measurement value in the G-PEEK group. In addition, in all groups, the average roughness values after brushing were statistically significantly higher than those before brushing. All groups except G-PEEK are below the clinically acceptable SR value (0.2 µm) before and after brushing. T-PEEK and C-PEEK show better SR values.

Clinical significance: With this study, knowing the effect of mechanical brushing on the SR of modified PEEK materials which may become widely used in dentistry, will be a guide for clinicians.