Dental Research Journal最新文献

Background: Composite restorations are prone to hybrid structure degradation and microleakage over time, which causes destruction and discoloration of the restoration's margins, caries recurrence, postrestoration sensitivity, and pulp irritation. New fiber-reinforced restorations may reduce some of the disadvantages of conventional composite restorations. This study aimed to compare microleakage of fiber-reinforced and conventional composite restorations.

Materials and ethods: In this in vitro experimental study, 40 healthy extracted permanent premolars were included. The teeth were randomly divided into two groups: the first group consisted of teeth restored with fiber-reinforced composite and the second group consisted of teeth restored with conventional composite. In the teeth of both groups, two class II cavities were prepared, and then, according to the grouping, they were restored with composite or composite and fiber. Each cavity had a mesiodistal length of 2 mm, a buccopalatal width of 4 mm, and a depth of 5 mm, with proximal locations in the premolars. In the next step, the apex of all samples was sealed with adhesive wax, and the tooth surfaces were covered with two layers of nail polish and placed in 0.5% Fuchsin solution at room temperature for 24 h. Finally, the teeth were cut in half, and the extent of dye penetration was determined with a stereomicroscope equipped with a digital camera. The Mann-Whitney test was used to compare microleakage between groups. P ≤ 0.05 was considered statistically significant.

Results: The median of microleakage score was 1 (interquartile range [IQR] = 2) in the intervention group and 2 (IQR = 1) in the control group. The difference between groups was statistically significant (P = 0.012).

Conclusion: This study revealed significantly lower microleakage with fiber-reinforced composite compared to conventional composite.

Background: The current endodontic disinfection techniques may be supplemented with photodynamic therapy (PDT), which is believed to eliminate intracanal bacteria more efficiently. This in vitro study aimed to assess the antimicrobial effectiveness of PDT using various photosensitizers, in conjunction with a near-infrared diode laser (810 nm wavelength), in the root canals of teeth infected with Enterococcus faecalis. This research is crucial for determining the optimal PDT method for eliminating E. faecalis, thereby enhancing the effectiveness of endodontic disinfection techniques.

Materials and ethods: This in vitro experimental study was conducted on 50 intact human maxillary first molars, which were decoronated, and palatal roots were instrumented to ISO size X5. After autoclaving, roots were inoculated with E. faecalis (ATCC 29212; 10⁸ CFU/mL) and incubated anaerobically for 72 h. The roots were randomly divided into five experimental groups: control (C), laser alone (L), PDT with indocyanine green (ICG), PDT with methylene blue (MB), and PDT with cetrimide (CT) 2%. Root canals were flushed with phosphate-buffered saline, and serial dilutions were plated on agar. Colony-forming units were counted after 48-h incubation. Data were analyzed using one-way analysis of variance followed by Tukey's post hoc test for pairwise comparisons. A significance level of P < 0.05 was considered.

Results: PDT with ICG resulted in complete eradication of E. faecalis (0 CFU/mL), whereas PDT with MB and CT produced significant reductions (5.08 ± 0.2 and 5.55 ± 0.1 log₁₀ CFU/mL, respectively; P < 0.05). Laser alone reduced CFU/mL to 5.94 ± 0.07.

Conclusion: PDT with ICG and an 810 nm diode laser achieved complete eradication of E. faecalis, outperforming MB, CT, and laser alone. These results advocate for ICG-PDT as a potent adjunct in endodontic disinfection protocols.

Background: Dental impressions are a known potential vector for cross-contamination between patients and the dental laboratory. Effective disinfection is, therefore, a critical step in infection control protocols. This in vitro study aimed to evaluate and compare the antibacterial efficacy of ultraviolet (UV) radiation and 0.525% sodium hypochlorite solution for disinfecting two common impression materials: condensation silicone and alginate.

Materials and methods: This in vitro study employed a comparative experimental design to evaluate disinfection efficacy. A total of 195 samples were utilized, comprising 90 discs each of condensation silicone and alginate, alongside positive and negative controls (n = 9 and n = 6, respectively). All samples were experimentally contaminated with standardized suspensions of three pathogenic species: Streptococcus pyogenes (beta-hemolytic Group A), Pseudomonas aeruginosa, and Staphylococcus aureus. The disinfection protocols consisted of either exposure to 0.525% sodium hypochlorite spray for 10 min or treatment with UV radiation using a dedicated device ("Fast Steril"). Antibacterial efficacy was quantitatively assessed by enumerating the mean colony-forming units (CFUs) postdisinfection. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U-tests, with the significance level defined at α = 0.05.

Results: The analysis revealed a statistically significant difference in bacterial reduction based on the microbial species (P < 0.001). UV radiation demonstrated superior efficacy compared to sodium hypochlorite in disinfecting condensation silicone impressions (P < 0.05). Conversely, no significant difference was observed between the two disinfection methods for alginate impressions. Regarding bacterial susceptibility, the mean reduction in CFUs for S. pyogenes was significantly greater than for S. aureus and P. aeruginosa (P < 0.001), between which no significant difference was found (P = 1.0).

Conclusion: Within the limitations of this study, UV radiation proved to be a more effective disinfection method for condensation silicone impressions than sodium hypochlorite spray. For alginate impressions, both methods were equally effective. Given its efficacy and the superior dimensional stability of UV-treated impressions reported in the literature, the adoption of UV radiation is recommended as a viable and efficient method for disinfecting both condensation silicone and alginate impressions, thereby mitigating the risk of cross-infection in dental practice.

Background: Dental implants face challenges such as bacterial infiltration and peri-implantitis, emphasizing the need for a robust mucosal seal to ensure long-term success. This study aimed to evaluate the impact of polishing and glazing zirconia on the adhesion and survival of human gingival fibroblasts, which are critical for establishing this protective barrier.

Materials and methods: In this in vitro experimental study, 18 zirconia discs (2.5 mm thickness) were prepared, sintered, and divided into three groups: polishing, glaze, and simple. The polishing group underwent sequential polishing, whereas the glaze group was coated with glaze paste and heated in a vacuum oven; the simple group remained unaltered. Cell survival was assessed using direct and indirect 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, and cell adhesion was analyzed through fluorescence microscopy and quantitative fluorometry. Data analysis was performed using SPSS version 26, employing the Kolmogorov-Smirnov test for normality and one-way ANOVA (P < 0.05).

Results: Cell adhesion was significantly greater in the polished group compared to the simple group (P = 0.001) and the glazed group (P = 0.002). Cell survival did not significantly differ between the polished and plain groups (P = 0.111). However, the glazed group showed significantly higher cell survival compared to both the simple (P < 0.001) and polished groups (P = 0.004).

Conclusion: Within the limitations of this in vitro study, it can be concluded that polished zirconia surfaces promote greater gingival fibroblast adhesion. However, fibroblast cell viability was higher on glazed zirconia discs. These findings underscore the importance of zirconia surface treatments in improving gingival integration.

The integration of computer-aided design (CAD) and computer-aided manufacturing (CAM) technology has significantly transformed restorative dentistry. This review explores the game-changing influence of CAD/CAM systems in restorative dentistry, emphasizing the clinical performance, mechanical attributes, and esthetic potential of contemporary materials such as zirconia, lithium disilicate, polyetheretherketone, polymethylmethacrylate, and advanced resin composites.This systematic review, conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and structured using the PICO framework, comprehensively explored evidence on CAD/CAM dental materials. A thorough search of PubMed, Scopus, Cochrane Library, Web of Science, and Google Scholar (2015-2025) initially identified 1300 records. After rigorous screening and eligibility assessment, studies addressing clinical indications, mechanical performance, and material-specific outcomes of CAD/CAM restorations were included for qualitative synthesis. Lithium disilicate and zirconia emerged as frontrunners in fracture resistance, marginal adaptation, and long-term esthetics. Glass-ceramics and nanohybrid composites demonstrated high performance in posterior and veneer applications. Comparative trials favored CAD/CAM over conventional restorations in precision, fit, and durability. Risk-of-bias assessment indicated predominantly low bias across key domains, ensuring reliability of findings. CAD/CAM materials combine digital precision with clinical excellence, offering strong mechanical performance and refined esthetics for optimal functional outcomes. Clinical evidence highlights their accuracy, efficiency, and long-term success compared to traditional restorative techniques.

Background: Chronic periodontitis is an infectious disease of the oral cavity that causes progressive destruction of periodontal tissues, leading to structural changes like attachment loss, bone resorption, resulting in bony defects, and potential tooth loss if left untreated. Effective drugs, such as alendronate, rosuvastatin (RSV), atorvastatin, melatonin, and metformin (MF), have been used as adjuncts to scaling and root planning and require evaluation for their comparative effectiveness in treating bony defects in patients with chronic periodontitis. This study aims to compare the effectiveness of these drugs for treating such defects.

Materials and methods: This network meta-analysis (NMA) was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and registered in PROSPERO (CRD42024600432). A comprehensive search of PubMed, Scopus, and Cochrane Library identified 11 eligible randomized clinical trials reporting changes in clinical attachment level (CAL) and bone fill (BF) at 6 months posttreatment. The NMA systematically compared treatment outcomes across different intervention groups.

Results: MF was the most effective treatment for CAL and BF at 6 months. Ranking probabilities indicated that MF and RSV had the highest likelihood of being the most effective treatments.

Conclusion: These findings from the NMA suggest that MF may be an effective option for CAL improvement and BF. Further research is needed to validate these results and optimize treatment strategies for bony defects in chronic periodontitis.

Background: Dentin hypersensitivity (DH) is a prevalent clinical condition, occurring when exposed dentin reacts to various thermal, chemical, or mechanical stimuli. Although different interventions such as fluoride varnish, adhesives, and natural bioactive compounds have been tested, there is still a demand for more effective and durable solutions.This study aimed to evaluate the ability of a nanoemulsion containing Nigella sativa nanoparticles encapsulated in propolis nanomicelles to occlude dentinal tubules and to compare its performance with fluoride varnish under the simulated acidic and mechanical challenges.

Materials and methods: In this in vitro study, hydroethanolic extract of Nigella sativa was encapsulated in propolis-based micelles to prepare the nanoemulsion. Thirty-six extracted human third molars were sectioned at the mid-crown and randomly assigned to four groups (n = 9): (1) normal saline, (2) nanoemulsion (15-min immersion), (3) nanoemulsion (30-min immersion), and (4) 5% fluoride varnish. Each group was further divided into three subgroups: control (no challenge), acid challenge, and simulated toothbrushing. Scanning electron microscopy at × 4000 magnification was used to quantify the percentage of occluded dentinal tubules. Data were analyzed with the two-way analysis of variance and least significant difference post hoc tests at a significance level of P ≤ 0.05.

Results: Material type (P = 0.018), challenge regimen (P < 0.001), and their interaction (P < 0.001) significantly influenced occlusion percentage. The highest occlusion was observed with nanoemulsion (30-min immersion) in the acid challenge subgroup (46.78%), followed by nanoemulsion (15-min immersion) after toothbrushing (41.85%), and fluoride varnish in the acid challenge subgroup (37.19%). Acidic and brushing challenges significantly reduced occlusion in all groups (P < 0.001).

Conclusion: Nanoemulsion containing Nigella sativa nanoparticles within propolis nanomicelles demonstrated superior dentinal tubule occlusion compared to fluoride varnish, with notable resistance to acid and brushing challenges. Given their natural origin, anti-inflammatory, and remineralizing properties, such nanoformulations may offer an effective and biocompatible alternative for managing DH. Clinical studies are recommended to validate these findings in vivo.

Background: Accelerating orthodontic space closure while minimizing anchorage loss remains a clinical priority. Micro-osteoperforation (MOP) has emerged as a minimally invasive technique to enhance tooth movement. This study aimed to compare the effectiveness of two MOP protocols on the rate and pattern of maxillary extraction space closure.

Materials and methods: In this parallel three-arm randomized controlled trial, 30 patients (17-30 years) with 3-4 mm of residual maxillary extraction space were randomly assigned to MOP1, MOP2, or control groups (n = 10 each). All underwent space closure using 0.019" × 0.025" stainless steel archwires and 150 g NiTi closed coil springs. MOP1 involved four perforations (two buccal, two palatal) at the extraction site center; MOP2 included additional perforations mesial and distal to the first molar. MOPs were performed monthly for 3 months. Primary outcome was space closure rate assessed via monthly three-dimensional intraoral scans. Secondary outcomes included angular tipping (PA radiographs) and relative anterior/posterior tooth movement. Statistical analysis used ANOVA, Kruskal-Wallis, and nonparametric post hoc tests (P < 0.05).

Results: Thirty patients (11 males, 19 females) were equally divided into MOP1, MOP2, and control groups. After 3 months, mean space closure was 0.88 mm greater in MOP1 and 0.90 mm greater in MOP2 compared to control. The 0.02 mm difference between MOP1 and MOP2 was clinically negligible. Control showed the greatest tipping, whereas MOP2 had the least. No adverse events were observed.

Conclusion: Monthly application of MOP significantly accelerates space closure and reduces tipping without increasing anchorage loss. The difference between MOP protocols was minimal and clinically negligible.

Background: This study aimed to histopathologically compare the efficacy of 5% melatonin (MEL) gel and 1.2% rosuvastatin (RSV) gel on bone regeneration in rat calvarial defects.

Materials and methods: In this animal study, 8-mm defects were created in the calvaria of 24 adult male Wistar rats weighing 200 g. The rats were randomly assigned to three groups (n = 8). The defects were filled with placebo gel (methylcellulose with no active ingredient) in Group I, 5% MEL gel in Group II, and 1.2% RSV gel in Group III. The rats were sacrificed after 4 weeks. Hematoxylin and eosin (H and E) staining was used to prepare histological sections. Statistical analysis was performed using the ANOVA and Tukey tests (α =0.05).

Results: Osteogenesis was significantly higher in the MEL and RSV groups than in the control group (P < 0.05). However, the difference between the MEL and RSV groups was not significant (P > 0.05).

Conclusion: Osteogenesis was significantly higher in the MEL and RSV groups than in the control group (P < 0.05). Local administration of MEL and RSV can be used as a stimulant of bone formation. However, more investigations are required to evaluate the bone regeneration capacity of MEL and RSV gels.

Background: This study aimed to synthesize mesoporous zinc oxide nanoparticles (ZnO NPs) and evaluate their effect as dentin pretreatments on the microshear bond strength (μSBS) of a universal adhesive.

Materials and methods: This in vitro experimental study used 100 extracted human molars sectioned to expose mid-coronal dentin. Samples were divided into five groups (n = 20) based on pretreatment: no treatment, chlorhexidine (CHX), calcined mesoporous ZnO NPs, noncalcined mesoporous ZnO NPs, and ZnO NPs. Each group was subdivided into two subgroups (n = 10) based on the universal adhesive application mode: etch-and-rinse (E and R) or self-etch (SE). Pretreatments were applied for 1 min. Composite resin was bonded using a universal adhesive. After 24 h of storage in distilled water at 37°C, μSBS testing was performed. Statistical analysis included the Shapiro-Wilk test for normality, two-way analysis of variance with Tukey's post hoc test, and t-tests, with significance set at P < 0.05.

Results: The noncalcined mesoporous ZnO NP group showed the highest μSBS, followed by the ZnO NP group, with significant differences compared to other groups (P < 0.05). Lower μSBS values were observed in the calcined mesoporous ZnO NP, CHX, and untreated groups. The adhesive application mode had a significant effect only in the untreated and calcined mesoporous ZnO NP groups (P < 0.05), with SE yielding higher μSBS than E and R.

Conclusion: Noncalcined mesoporous ZnO NPs enhanced dentin bond strength more effectively than other pretreatments, including CHX, indicating their potential as a promising alternative in adhesive dentistry.