Biomaterial investigations in dentistry最新文献

Introduction: Debonding of silicone prostheses from metal substructures is a frequently reported complication in prosthodontics. Polyether ether ketone (PEEK) has emerged as a promising alternative framework material owing to its favourable biomechanical properties; however, its limited bond strength to silicone remains a concern. The present study aimed to evaluate the shear bond strength between PEEK and maxillofacial silicone following laser etching of PEEK and subsequent accelerated ageing.

Materials and methods: According to ISO 10477:2020, 128 PEEK specimens were fabricated using Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) with 10 mm diameter and 3 mm thickness, and silicone specimens with 5 mm diameter and 2.5 mm height. The specimens were categorised into: Group 1-no surface treatment, Group 2-Al₂O₃ air abrasion, Group 3-98% sulphuric acid etching, and Group 4-laser irradiation. The silicone specimens were bonded to PEEK and kept at room temperature for 24 h for polymerisation, and were subjected to accelerated ageing for 252, 504, and 1,008 h. The shear bond strength was evaluated using universal testing machine at 1 mm/min crosshead speed. The comparison within groups was done using one-way analysis of variance (ANOVA) and multiple group comparison was done using Tukey's HSD (Honestly Significant Difference) post-hoc analysis.

Results: Statistical analysis showed that surface pretreatment had a significant effect on bond strength (p < 0.05). Laser treatment and air abrasion produced significantly higher bond strengths compared to sulfuric acid etching, while no significant difference was found between laser treatment and air abrasion. Accelerated ageing time also had a significant influence, with bond strength values decreasing progressively from 252 h to 1,008 h across all pretreatment groups.

Conclusion: Surface pretreatment significantly influenced the adhesion of maxillofacial silicone to PEEK. Laser treatment and air abrasion provided superior and statistically comparable bond strengths, whereas sulfuric acid etching was less effective. Accelerated ageing reduced bond strength over time, highlighting the effect of ageing conditions on the durability of adhesion.

Objective: The objective of this study was to coat orthodontic nickel titanium (NiTi) archwires with nano-particles (NP) of silver (Ag) combined with nano polytetrafluoroethylene (PTFE) to produce a smooth antimicrobial nanocomposite layer by using a radio frequency (RF) sputtering process and to evaluate the coated surfaces in terms of morphology, nano-roughness, adhesion strength, hardness, and antimicrobial activity.

Materials and methods: Super-elastic NiTi archwires (diameter = 0.4 mm, length = 160 mm) were surface cleaned and sterilized prior to the RF sputtering, using a mixture of nano Ag powder (20 nm; purity > 99.95%) and PTFE powder (25 nm; purity > 99.95%). X-ray diffraction apparatus (XRD), flex atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were used to characterize the morphology and nano roughness of the coated archwires. Lactobacillus acidophilus (L. acidophilus) and Streptococcus mutans (S. mutans) were selected to evaluate the antimicrobial activity.

Results: A uniform and homogeneous nanocomposite coating was obtained without agglomeration. Surface roughness values decreased with increasing sputtering time, while the coated samples exhibited excellent antibacterial activity against both bacterial strains. AFM analysis demonstrated that sputtering time strongly influenced adhesion resistance, hardness, and coating stability, and the antibacterial activity was highly effective against both L. acidophilus and S. mutans.

Conclusion: The sputtering time of 30 min gave a smooth coating layer on the surface of NiTi archwire with strong antimicrobial resistance that offers significant potential for dental applications.

Aim and objectives: To evaluate the antibacterial, antibiofilm, antioxidant, and anti-inflammatory properties of Amphiroa fragilissima and assess its potential for dental and orthodontic use.

Materials and methods: Methanolic extracts of A. fragilissima, collected from Rameshwaram, India, were tested against Streptococcus mutans, Enterococcus faecalis, Escherichia coli, and Shigella sonnei using the Kirby-Bauer method. Antibiofilm activity was analyzed via Crystal Violet staining. Antioxidant potential was assessed using 2,2-Diphenyl-1-picrylhydrazyl radical scavenging, and anti-inflammatory activity was measured via a bovine serum albumin assay.

Results: The extract showed dose-dependent antibacterial activity, with maximum inhibition observed at 100 µg/mL. Biofilm inhibition also increased with concentration. Antioxidant assays revealed significant radical scavenging activity, with results comparable to controls at higher concentrations. Anti-inflammatory testing showed reduced protein denaturation in treated samples, with effects similar to the positive control and significantly better than the blank.

Conclusion: Amphiroa fragilissima demonstrates strong antibacterial, antibiofilm, antioxidant, and anti-inflammatory activities, along with remineralization potential due to its calcium-rich composition. These properties support its potential as a natural, multifunctional agent for dental and orthodontic applications. Further in vivo studies are recommended to validate its clinical use.

Background: Alveolar ridge preservation (ARP) is critical for minimizing post-extraction bone loss and maintaining ridge dimensions essential for prosthetic replacement. Eggshell-derived hydroxyapatite (EHA), owing to its compositional similarity to natural bone and promising biological properties, has emerged as a potential alternative to conventional graft materials such as Demineralized Freeze-Dried Bone Allograft (DFDBA). The aim of the study was to compare the clinical and radiographic outcomes of EHA and DFDBA in ARP.

Materials and methods: This prospective randomized clinical trial involved 20 patients requiring mandibular posterior extractions, which were assigned to two groups: EHA (test) and DFDBA (control). In both groups, bone grafts were combined with injectable Platelet-Rich Fibrin (i-PRF) to form sticky bone and sealed with Advanced Platelet-Rich Fibrin (A-PRF) membranes. Clinical parameters such as Plaque Index (PI), Gingival Index (GI), Width of Keratinized Gingiva (WKG) and radiographic parameters such as Vertical Ridge Height, Horizontal Ridge Width, and Bone Density were evaluated at baseline and Healing Index (HI) was evaluated after 2 weeks.

Results: Both study groups exhibited significant improvements in PI, GI, WKG, vertical ridge height and horizontal ridge width within group with no significant difference between the groups. However, EHA demonstrated less ridge reduction compared to DFDBA with no significant changes in bone density. Wound healing at 2 weeks showed no significant difference between groups.

Conclusions: EHA with platelet-rich fibrin (PRF) is an effective, affordable, and biocompatible option for ARP. EHA demonstrated greater ridge dimensional stability and similar bone density improvements compared to DFDBA, with minimal resorption and favorable healing outcomes.

Purpose: The interest in mechanical properties of membranes derived from different autologous platelet concentrates (PCs) stems from the need to possess certain qualities to bring about the necessary clinical outcomes as regenerative materials. Despite recent advances leading to procurement of membranes from variety of PCs, there is a dearth in studies comparing and evaluating the mechanical characterisation of these potential membranes. Hence, the present study evaluated the mechanical properties of five different PCs.

Materials and methods: 9 mL of intravenous blood was taken and collected at different intervals for procurement of Leukocyte Rich Platelet Rich Fibrin (L-PRF), Advanced-Platelet Rich Fibrin (A-PRF), Titanium-Platelet Rich Fibrin (T-PRF), Selphyl Platelet Rich Fibrin Matrix (Selphyl PRFM), Merisis Platelet Rich Fibrin Matrix (Merisis PRFM). Dynamic Mechanical Analysis technique by surface indentation test using a Triboindenter at 200 μN load was performed to analyse the mechanical properties (hardness, storage modulus, loss modulus, and Tan δ) of the samples.

Results: On comparing the hardness, it was found that A-PRF, Merisis PRFM and Selphyl PRFM demonstrated higher hardness. As for storage modulus, loss modulus and Tan δ, PRFM group (Merisis PRFM and Selphyl PRFM) performed significantly (p < 0.01) better than PRF group (L-PRF, A-PRF, T- PRF).

Conclusion: Platelet Rich Fibrin Matrix group membranes demonstrated superior mechanical properties in comparison to PRF group membranes, and therefore seem a preferable choice as barrier membranes as well as for various regeneration purposes.

Background & objectives: Platelet-rich fibrin (PRF) has shown promise in periodontal surgery and is found to promote bone regeneration. However, its limitations include low elasticity, short lifespan, and poor storage stability. This study aimed to overcome these limitations by developing frozen PRF and comparing the mechanical and structural properties of advanced-PRF (A-PRF) and two frozen PRF storage protocols.

Methodology: This in vitro study used blood samples from 14 healthy volunteers to prepare A-PRF, which was stored at -20°C for 1 day (Fz-PRF1) or 7 days (Fz-PRF7). The study evaluated mechanical properties (tensile strength and elasticity) using a universal testing machine, and structural properties (Blood Elements Adhesion Index [BEAI] and fibrin density) using scanning electron microscopy (SEM) analysis. Results were analysed by Chi-square, independent t-tests, and Tukey post-hoc tests.

Results: Comparing three PRF membranes, Fz-PRF7 showed significantly higher tensile strength than A-PRF and Fz-PRF1, and higher modulus of elasticity than A-PRF. However, SEM analysis revealed no significant differences in BEAI and fibrin density scores across groups.

Conclusion: Fz-PRF7 showed improved mechanical properties, specifically tensile strength and elasticity, compared to A-PRF, overcoming some limitations of conventional PRF.

Objective: The aim of the present study was to evaluate the antimicrobial activity of resin-modified glass ionomer cements (RMGICs) supplemented with red propolis ethanolic extract (RPEE) against Streptococcus mutans cultures.

Materials and methods: Four RMGICs (Gold Label, Ionolux, Vitro Fill, and Riva) were used with the addition of RPEE at concentrations of 11% and 20%. For the control groups, the cements were manipulated and light-cured according to the manufacturers' instructions. S. mutans strains from stock cultures were grown in brain heart infusion (BHI) broth. Cement samples were placed in direct contact with the microorganism for 48 h in a bacteriological incubator. After this period, the diameters of the inhibition zones were measured using a digital caliper.

Results: Data analysis showed a significant increase in the size of the inhibition zones for Gold Label and Vitro Fill RMGICs in the groups with 11% RPEE, compared to their respective controls. When comparing different cement brands containing 11% RPEE, Gold Label and Vitro Fill exhibited significantly larger inhibition zones than Ionolux.

Conclusion: The addition of 11% RPEE was shown to enhance the antimicrobial activity of two of the four tested RMGICs, with Gold Label and Vitro Fill demonstrating the greatest antimicrobial potential following supplementation with RPEE.

Introduction: Three-dimensional (3D) printing, particularly Masked Stereolithography (MSLA), has emerged as a transformative technology in orthodontics for the fabrication of precise dental models. However, the mechanical integrity of these models, especially compressive strength, is critical during procedures such as thermoforming of clear aligners. This study aimed to evaluate the effect of different chemical post-processing methods on the compressive strength of MSLA-printed dental models.

Materials and method: A total of 40 cylindrical resin samples (10 mm in height and 5 mm in diameter) were fabricated using an MSLA printer and divided into four groups (n = 10). Group 1: untreated group (acted as the control group), while Groups 2, 3, and 4 were treated with acetone, propylene glycol, and isopropyl alcohol, respectively. All treated samples were immersed in their respective chemicals for 5 min at room temperature. The compressive strength of each sample was measured utilising a Universal Testing Machine (UTM), and results were statistically analysed using Analysis of Variance (ANOVA) followed by Tukey's post hoc test.

Results: The compressive strength varied with statistical significance among the groups (p = 0.001). Compared to the untreated control group (107 ± 35 MPa), post-processing in propylene glycol (139 ± 48 MPa) or isopropyl alcohol (106 ± 10 MPa) resulted in statistically similar compressive strength, whereas post-processing in acetone (86 ± 19 MPa) led to significantly lower compressive strength. Furthermore, post-processing in propylene glycol resulted in significantly higher compressive strength than did post-processing in isopropyl alcohol or acetone. Propylene glycol showed greater variability, which makes its beneficial properties questionable.

Conclusion: In conclusion, chemical post-processing significantly influences the compressive strength of MSLA-printed models. Acetone had a deleterious impact on compressive strength. Isopropyl alcohol proved to be an acceptable solvent. Propylene glycol showed large variability in results, warranting further investigation.

Context: Ultrafast Protooth is a calcium silicate cement with a rapid initial setting time of 2 minutes. Its fluoride release, apatite-forming capability and favourable biocompatibility make it a potential candidate for vital pulp therapy.

Aim: This case series evaluates the coronal pulpotomy outcomes using Ultrafast Protooth in permanent molars having closed apices diagnosed with symptomatic irreversible pulpitis.

Materials and methods: After anaesthetisation, the tooth was isolated and disinfected, and caries were excavated. Vitality was re-assessed intra-operatively based on the bleeding response. Coronal pulpotomy was performed using Ultrafast Protooth if haemostasis was achieved within the clinically accepted time. After confirming that the material had set, based on the manufacturer's guidelines and clinical judgement, a permanent composite restoration was placed, followed by postoperative radiographs.

Results: All teeth remained asymptomatic, showing no clinical signs of pain, inflammation, or infection and responded positively to pulp sensibility tests. Radiographs confirmed no periapical disease during the 1-year follow-up.

Conclusion: Ultrafast Protooth showed favourable 1-year clinical and radiographic outcomes. Continued follow-up and further controlled trials are warranted to validate these findings.

Objective: The purpose of this study was to compare the chromatic differences (ΔE) of three nanohybrid composite resins (Filtek™ Z350 XT, FORMA™ and Palfique LX5) after increasing exposures (0, 250, 500, 750, 1,000, 1,250 and 1,500 puffs) to e-cigarette vapours.

Materials and methods: The study was conducted with an in vitro experimental design, in which a total of 66 resin discs measuring 10 mm × 2 mm were used and distributed as follows: 22 discs of each brand of resin tested. After 24 hours storage in water at 37°C and 500 cycles of thermal cycling (5°C-55°C), they were exposed to the vapour of a 'Vuse' brand electronic cigarette dispensed in an artificial vacuum system, graded into levels consisting of six puff each. Colour parameters were measured according to the CIELab system with a Konica Minolta CR-400 colorimeter before (baseline) and after each cycle of puffs, and the difference in colour (ΔE) was calculated. For statistical analysis, the mixed analysis of variance (ANOVA) test and the post hoc test of Games‑Howell, was used, with a confidence level of 95%.

Results: Filtek™ Z350 XT resin had an average ΔE value of 3.239 ± 1.30; FORMA™ showed an ΔE value of 4.737 ± 1.672, and Palfique LX5 had a mean ΔE of 1.614 ± 0.867. Significant differences were found between resin brands (p < 0.001), while increasing puffs did not significantly influence ΔE within each resin (p > 0.05).

Conclusion: Chromatic stability of composites after exposure to e-cigarette vapours varied depending on the material brand, with FORMA™ resin showing clinically unacceptable chromatic differences, whereas Filtek™ Z350 XT and Palfique LX5 resins showed clinically acceptable chromatic differences, with the latter showing greater resistance to colour change and therefore greater chromatic stability. These findings serve as a guide in decision-making relative to the selection of restorative materials indicated for patients with vaping habits.