Biomaterial investigations in dentistry最新文献

Red marine seaweeds, particularly those belonging to the genus Rhodophyta, possess a robust structural framework and are rich in biologically active compounds such as carrageenan, agar, collagen, and alginate. These natural resources are abundant and have attracted significant attention for their therapeutic potential in oral healthcare. This review highlights the applications of red marine seaweeds in dentistry, focusing on their roles in maintaining oral health, facilitating wound healing, exhibiting antibacterial properties, and contributing to tooth remineralization. Notably, their anti-inflammatory activity supports the management of conditions such as gingivitis, periodontitis, and oral ulcerations, while their antibacterial and antifungal actions effectively inhibit oral pathogens such as Streptococcus mutans, a primary contributor to dental caries. Furthermore, carrageenan-based biodegradable films derived from red seaweeds demonstrate promising potential as controlled drug delivery systems and tissue-regenerative biomaterials within the oral cavity. Beyond clinical applications, seaweeds can also serve as sustainable sources for formulating naturally derived oral hygiene products - including mouthwashes, toothpastes, and gels - offering eco-friendly alternatives to synthetic chemicals. However, despite these advances, broader clinical adoption requires comprehensive and well-designed clinical trials to validate efficacy and safety. Overall, this review underscores the emerging potential of red marine seaweeds as sustainable, bioactive resources for innovative dental therapeutics, while emphasizing the need for continued translational and clinical research.

The stability and functionality of complete dentures depend on various clinical and material factors, such as retention, adaptation, color change, microhardness, and surface roughness. Relining aims to re-establish the fit of the prosthesis to the supporting tissues, and it is carried out using materials such as acrylic resins. This study aimed to evaluate the color, microhardness and roughness properties of three relining acrylic resins: Kooliner (GC America, USA), TDV-Cold (TDV, Brazil), and Ufi Gel Hard C (VOCO, Germany), after combined use with three different adhesives (Corega, Fixodent - Haleon, UK; and Poligrip - P&G, USA) for 2 months, followed by aging by thermocycling (5.000 cycles). Color, microhardness, and roughness were analyzed on 120 samples at times T0 (initial), T1 (after 2 months), and T2 (after thermocycling). Additionally, characterization by energy-dispersive X-ray spectroscopy and scanning electron microscopy was performed at T0 and T2. The results showed that time had a significant influence on all the properties evaluated, with an increase in microhardness and roughness over time. Ufi Gel Hard C showed greater color stability and microhardness, even after aging, a behavior associated with the presence of elements such as silicon and barium in its composition. Roughness was also more evident in this relining acrylic resin, as confirmed by the SEM data and images. The reliners analyzed showed distinct behavior in response to aging and thermocycling, with Ufi Gel Hard C standing out for its greater stability. Time was the main factor influencing color, microhardness, and roughness properties.

Background: Bioceramic materials have emerged as a significant advancement in endodontics, offering excellent biocompatibility, sealing ability, and bioactivity.Their use has expanded in recent years, particularly for pulp capping, perforation repair, and regenerative procedures.

Objectives: This study aimed to assess the knowledge of bioceramics among private practice dentists, evaluate the frequency of use of sealing and filling bioceramics, and examine the applied clinical protocols as well as potential shortcomings.

Materials and methods: This cross-sectional study was conducted according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines, based on an epidemiological Knowledge, Attitudes, and Practices (KAP) survey. It was carried out among Tunisian private practice dentists. Data were processed and analyzed using Excel 2007 and Statistical Package for the Social Sciences (SPSS) Statistics 21.0. The sample size was calculated using the standard formula for estimating a proportion in a cross-sectional study, and participants were randomly selected. Participation was voluntary, anonymous, and confidential.

Results: A total of 200 dentists participated. Only 54.5% reported using sealing bioceramics, with 35.05% using them in all cases, 19.94% for periapical lesions, and 16.92% for root perforations. Approximately half of the dentists (53.01%) observed faster healing when using these sealers. Regarding filling bioceramics, 67.5% of participants used them, with a preference for MTA. These materials were indicated for various clinical situations, including repair of floor perforations, pulp capping, apexification of immature permanent teeth, and repair of root perforations. However, 45.61% of participants reported treatment failures when using these bioceramics, with failure to adhere to one of the endodontic treatment steps identified as the primary cause.

Conclusion: This study concluded that younger dentists tend to use bioceramics more frequently, filling bioceramics are better known than sealing ones, and most participants are familiar with the clinical indications of these materials. It is essential to provide further guidance and recommendations on the clinical application of bioceramics to optimize treatment outcomes.

Objective: The study focused on drawing a comparative evaluation amongst four commercially available implant luting cements used to retain implant-supported zirconia restorations fabricated using a Computer-Aided Design-Computer-Aided Manufacturing (CAD-CAM) system.

Materials and methods: A heat-activated polymethyl methacrylate (PMMA) model was fabricated to mount four implant abutment-analogue complexes. These complexes were scanned using a digital laboratory scanner to mill 60 zirconia copings using CAD-CAM software. The copings were divided into four groups depending on the type of implant luting cement used (n = 15). The zirconia copings were then cemented over titanium abutments and a tensile load at a crosshead speed of 1 mm/min was applied to the samples to perform a pull-out test using Universal Testing Machine. Thereafter, the load required to de-cement each coping was obtained, thus the retention for each coping was measured.

Statistical analysis: One-way analysis of variance (ANOVA) was advocated to statistically analyse the results and the post hoc Bonferroni test was used for multiple comparison using Statistical Package for the Social Sciences (SPSS) software.

Results: Multilink implant showed highest tensile strength (2.24 ± 1.01 kgf/mm²) being statistically significantly different from the other three cements (p < 0.001). This was followed by TgImplaCem (0.82 ± 0.32 kgf/mm²) and Temp-Bond NE (0.71 ± 0.13 kgf/mm²). The lowest tensile strength was exhibited by ImplaLute (0.31 ± 0.10 kgf/mm²). Intergroup comparison between TgImplaCem, Temp-Bond NE, and ImplaLute cements did not show statistically significant difference in tensile strength values (p < 0.001).

Conclusion: It was concluded that both non-eugenol zinc oxide provisional luting cement (TgImplaCem) and dual-curing resin-based implant cement (Temp-Bond NE) can be advocated to cement implant-supported prostheses since they both permit adequate retention with ease of retrievability.

Objective: Bracket detachment remains a frequent complication in orthodontic treatment, often resulting in extended treatment duration and increased clinical workload. Nano-hydroxyapatite (n-HAp), due to the excellent biocompatibility and bioactivity, has been explored as a potential filler to improve the performance of dental adhesive systems. This study aimed to evaluate the effect of incorporating 2 wt% n-HAp derived from Amusium pleuronectes (Asian moon scallop) shells into orthodontic adhesive on shear bond strength (SBS) to enamel and on Adhesive Remnant Index (ARI) scores.

Materials and methods: Thirty-two extracted human maxillary premolars were randomly divided into two groups (n = 16). The experimental group used orthodontic adhesive modified with 2 wt% n-HAp, while the control group used unmodified commercial adhesive. Standard bracket bonding procedures were performed, followed by SBS testing using a universal testing machine. After debonding, the adhesive remnants were evaluated under a stereomicroscope to determine ARI scores. SBS data were analyzed using an independent t-test, and ARI scores were assessed using the Mann-Whitney U test, with significance set at p < 0.05.

Results: The experimental group exhibited a significantly higher mean SBS of 16.54 ± 2.98 MPa compared to 8.91 ± 1.63 MPa in the control group (p < 0.05). ARI scores showed no statistically significant difference between the two groups (p > 0.05), with mean scores of 3.44 ± 1.23 and 3.38 ± 1.22, respectively.

Conclusion: Incorporation of 2 wt% nano-hydroxyapatite derived from Asian moon scallops into an orthodontic adhesive improved bond strength without altering failure patterns, suggesting its potential as an effective bioactive filler in orthodontic applications.

Objective: This study aimed to compare the effect of two different generations of bisphosphonates (BPs) on bone repair assisted by an alloplastic bone graft (spheres of nanostructured carbonate apatite/calcium, CHA) in a non-critical defect in the rat femur.

Materials and methods: Thirty-six female Wistar rats were randomly assigned into six groups: Control group (blood clot), carbonate apatite (CHA) alone, Zoledronate (Zol) with blood clot, Clodronate (Clo) with blood clot, Zol+CHA, and Clo+CHA. Drugs were administered intraperitoneally (Zol: 0.6 mg/kg; Clo: 20 mg/kg) every 30 days for 60 days before surgery. Standardized monocortical femoral defects (2 mm) were created and filled according to group assignment. After 30 days of healing, samples were harvested for histological and histomorphometrical evaluation. New bone formation and remnant biomaterial were quantified. Statistical analysis included the Kruskal-Wallis test and Dunn's post hoc (p < 0.05), along with Pearson and Spearman correlation analyses.

Results: Histological analysis revealed enhanced new bone formation in groups treated with BPs, especially when combined with CHA. The Zol+CHA group exhibited the highest new bone formation (24.0 ± 4.0%), significantly greater than Control (2.0 ± 0.5%; p = 0.011) and CHA (5.0 ± 1.2%; p = 0.0017). The Clo and Clo+CHA groups also showed significant improvements (19%) compared to the Control (p = 0.03) and CHA (p = 0.04). Remnant biomaterial was significantly greater in Zol+CHA (15.0 ± 2.0) and Clo+CHA (15.0 ± 2.0%) than in CHA alone (8.0 ± 1.0%; p = 0.022), suggesting inhibition of bone graft resorption by BPs. Correlation analysis revealed a strong positive association between remnant biomaterial and new bone formation (Spearman ρ = 0.94, p = 0.005; Pearson r = 0.88, p = 0.021), supporting the biological synergy of CHA and BPs in bone repair.

Conclusion: Both bisphosphonates enhanced bone repair in the femoral defect model, demonstrating a synergistic effect when combined with nanostructured CHA. Zoledronate required the presence of the biomaterial to exert its osteogenic influence, while Clodronate stimulated new bone formation independently. These findings indicate that generation-specific differences among bisphosphonates may guide their future use in bone tissue engineering strategies.

Objective: To evaluate in vitro the effect of two commercial mouthwashes, Encident Brackets^® (fluoride- and chlorhexidine-containing) and BambooSmile^® (natural formulation) on the surface roughness of nickel-titanium (NiTi) orthodontic archwires.

Materials and methods: Thirty rectangular NiTi archwire segments (0.019 × 0.025", Orthometric) were divided into three groups (n = 10 each): control, Encident Brackets^®, and BambooSmile^®. Samples were pre-immersed in artificial saliva for 24 h, then exposed for 1.5 h to the respective solutions, simulating 30 days of clinical use. Surface roughness (Rz) was measured before and after immersion using a Marsurf PS10 profilometer. Statistical analysis included Student's t-test and ANOVA (p < 0.05).

Results: Both mouthwashes significantly increased surface roughness compared to baseline (p < 0.05). Mean Rz values rose from 0.798 to 2.208 μm in the Encident Brackets^® group and from 0.782 to 2.085 μm in the BambooSmile^® group. However, no significant differences were observed between the two experimental groups after treatment (p > 0.05).

Conclusions: Exposure to both conventional and natural mouthwashes resulted in significant surface alterations of NiTi archwires. Although Encident Brackets^® produced slightly higher roughness values, its effect was comparable to BambooSmile^®. These findings highlight the importance of considering mouthwash composition during orthodontic treatment, as increased surface roughness may compromise sliding mechanics, favor bacterial adhesion, and affect periodontal health. Further in vivo studies are recommended to validate these results under clinical conditions.

Laser-assisted endodontic treatments have gained popularity over the last decade. This study evaluated the flexural strength (FS), fatigue resistance, and surface characteristics of root dentine after laser-assisted endodontic protocols. Forty extracted, caries-free canines were used to prepare root dentine beams (n = 37/group). Beams were irradiated with (1) Er:YAG 2,940 nm (20 mJ, 0.3W, 15 Hz, 50 ms), (2) Er,Cr:YSGG 2,780 nm (2.25W, 50 Hz, 140 ms), and (3) 940 nm diode laser (1W, CW). The non-irradiated beams served as control group. Both erbium groups were treated with laser-activated irrigation with radial firing tips (RFTs); meanwhile, the diode group irradiation protocol, using RFT, was dry. Specimens underwent quasi-static loading (n = 12) and cyclic loading for fatigue behaviour (n = 25) using 4-point flexure test. Scanning electron microscopy analysis was performed. Data were analysed using analysis of variance and Kruskal-Wallis tests (α = 0.05). No significant difference was found in FS or fatigue resistance after laser-assisted treatment (p > 0.05), but endurance limits improved by 18% (Er:YAG) and 19% (Er,Cr:YSGG) compared to controls. These findings suggest that Er:YAG, Er,Cr:YSGG, and 940 nm diode lasers, when applied with recommended parameters, do not compromise dentine fatigue strength. Therefore, they may be safely integrated into root canal treatment protocols.

Introduction: The current research tested the assumption that the addition of nano-carbonated hydroxyapatite (nCHAp) to Mineral Trioxide Aggregate (MTA) Angelus would modify its physicochemical properties and alter compositional characteristics that were relevant to the development of bioactive phases, without altering normal hydration dynamics.

Methods: MTA angelus was blended with 5 wt% nano-CHAp and subjected to controlled hydration. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) was conducted to identify functional groups and affirm the inclusion of carbonate and phosphate ions. Phase composition was analyzed using X-ray diffraction (XRD). Surface morphology and elemental composition were analyzed by using Field Emission Scanning Electron Microscopy (FESEM) in conjunction with Energy Dispersive X-ray Spectroscopy (EDX). Porosity and microstructural integrity were also examined.

Results: ATR-FTIR spectra showed peaks corresponding to characteristic functional groups of carbonates (CO₃ ^2-) and phosphate (PO₄ ^3-), affirming the incorporation of nano-CHAp chemically. XRD patterns affirmed the preservation of key hydration phases such as portlandite, tricalcium silicate, calcite, and bismuth oxide, with new calcium phosphate phases due to inclusion of nano-CHAp. FESEM images showed more dense microstructure with reduced porosity and reformed particle packing. EDX analysis showed the inclusion of phosphorus and notable increases in calcium and carbon content, corresponding with nano-CHAp inclusion. The modified MTA angelus preserves primary hydration pathways while having enhanced biofunctional availability of ions and surface morphology.

Conclusion: Introduction of nano carbonated hydroxyapatite (nCHAp) brought about discernible changes in the composition of the cement matrix through the phase specific characteristics of XRD, ATR-FTIR, and energy-dispersive X-ray spectroscopy (EDS). These structural changes may create compositional environments that would support the development of mineral-related phases, but it would require further, more specific studies than the current one to confirm biological or clinical outcomes.

Objective: Irrigation is a clinical procedure in which needles of various designs, attached to syringes, are delivered by positive pressure to cleanse the root canals of infection-promoting agents. Despite being available in multiple designs and different materials, the irrigant does not necessarily reach every portion of the canal. This study compared four different needle designs in terms of depth of penetration of the needle (DOP), wear of the needle and fluid dynamics of the irrigant (FD).

Methods: Stereolithography was used to manufacture four 3D-printed single-rooted mandibular premolars with double curvature. The four needle designs used were Group I (NiTi open-ended, notched needle tip), Group II (Stainless steel, single-sided vented needle tip), Group III (Stainless steel, double-ended needle tip), and Group IV (Soft propylene, multi-vented needle tip) (n = 10 in each group). After assigning each tooth to a group, a stereomicroscope was used to measure the DOP. Pre- and post-irrigation scanning electron microscopy images of three randomly chosen needles from each group helped qualitatively determine the wear. Later, particle image velocimetry (PIV) experiments for each of the four needle designs were subsequently compared with those obtained from computational fluid dynamics (CFD).

Results: The open-ended syringe had the significantly lowest mean DOP as determined by one-way ANOVA and Tukey's post hoc test. Wear was significantly lowest in the non-metallic syringes. The PIV and CFD analyses were in close agreement with each other. The non-metallic needle exhibited the highest pressure and axial velocity near the apex.

Conclusion: The validated CFD models showed a greater canal coverage and irrigant flow from the non-metallic syringe in the double curvature root canal simulations; though with the highest risk of apical extrusion.