Search Results (1,097)

This study aims to compare the surface roughness and fracture resistance of implant-supported permanent crowns additively manufactured using composite resins (Crowntec, VarseoSmile) versus subtractively manufactured polymer-infiltrated hybrid ceramic (VITA Enamic) at various wall thicknesses using an experimental setup as close to clinical as possible. 180 crowns were fabricated in three thicknesses (1.0, 1.5, and 2.0 mm) and cemented onto titanium abutments. Experimental groups underwent thermal aging (10,000 cycles) to simulate one year of clinical service. Surface roughness was measured via profilometry, and fracture resistance was assessed using a universal testing machine. Composite resin crowns exhibited lower surface roughness and lower fracture resistance than subtractively manufactured crowns. No significant difference in fracture resistance was found between materials at 1.0 mm (p > 0.05). However, at 1.5 and 2.0 mm, hybrid ceramic network crowns showed significantly higher resistance (p < 0.01). It was concluded that, within the limitations of this 1-year simulated study, both material-method combinations met the biological threshold for surface roughness. Regarding fracture resistance, composite resins and hybrid ceramics satisfied clinical requirements for molar bite forces only at thicknesses of 1.5 mm and above. 1.0 mm thickness may pose a risk under high occlusal loads. Full article

Background/objective: To evaluate the effectiveness of resin infiltration in managing anterior molar incisor hypomineralization (MIH) defects, focusing on color improvement, lesion size reduction, sensitivity outcomes and patient aesthetic perception. Enamel defects in MIH result from a combination of environmental, systemic, and genetic factors, indicating a multifactorial etiology. These defects, particularly in anterior teeth, pose significant aesthetic and emotional challenges due to their high visibility. This study provides one of the few prospective clinical evaluations of resin infiltration for anterior MIH lesions, assessing not only objective clinical outcomes but also patients’ aesthetic perception. It further introduces a patient-centered approach by comparing aesthetic evaluations made by children and dental professionals over time. Methods: A total of 109 MIH-affected anterior teeth were treated using Icon^® resin infiltration (DMG, Hamburg, Germany) in this registered prospective clinical study (ClinicalTrials.gov: NCT05597956). Participants were classified as children (6–12 years) and adolescents (13–17 years) according to standard pediatric age definitions. Of these, 101 teeth were available for evaluation at the 6-month follow-up due to patient loss to follow-up. The evaluation included photographic follow-up, measurement of lesion size and color, and assessment of sensitivity. During follow-up visits, patients rated the appearance of their lesions using the FDI scale. Results: Before treatment, spectrophotometric analysis showed that lesions exhibited a reddish hue (mean a* = 2.12), were distinctly yellowish (mean b* = 23.20), and clearly differed from surrounding enamel (ΔE = 8.62). The brightness level (L* = 69.81) indicated medium-high luminosity. Lesion size was reduced by an average of 4.5 percentage points. Significant increases in L values and reductions in a* and b* components were observed, with clinically perceptible ΔE changes. Sensitivity improved in 36.6% of patients, who reported a 1–2 point decrease on the SCASS. Moreover, patients’ aesthetic perception significantly improved after Icon^® infiltration resin. Conclusions: Resin infiltration produced noticeable improvements in color, reduced lesion size and sensitivity, and enhanced aesthetic perception, making it a valuable treatment option for managing MIH-affected anterior teeth in children. Full article

Background and Objectives: Implant-supported rehabilitation after oral cancer surgery remains technically and biologically demanding due to altered anatomy, scar tissue, and prior radiotherapy. Digital workflows and hospital-based point-of-care (POC) manufacturing now enable personalized, prosthetically driven implant placement with static surgical guides fabricated within the clinical environment. This study reports the initial clinical experience of an academic POC manufacturing unit (UPAM3D) implementing static guided implant surgery in oral cancer patients and compares this approach with conventional outsourcing and dynamic navigation methods. Materials and Methods: A retrospective review of 30 consecutive cases (2021–2024) treated with POC-manufactured static guides was conducted using data from the UPAM3D registry. Each record included design, fabrication, and sterilization parameters compliant with ISO 13485 standards. Demographic, surgical, and prosthetic variables were analyzed, including anatomical site (maxilla or mandible), guide type, material, radiotherapy history, number of Ticare Implants^®, and loading strategy. Results: All surgical guides were designed and 3D printed in-house using biocompatible resins (BioMed Clear, Dental SG, or LT Clear). The annual number of POC procedures increased progressively (2 → 6 → 6 → 16). Most cases involved oncologic reconstructions of the maxilla or mandible, including irradiated fields. When recorded, primary stability values (mean ISQ ≈ 79) allowed immediate or early loading (ISQ ≥ 70). No major intraoperative or postoperative complications occurred, and all guides met sterilization and traceability standards. Conclusions: Point-of-care manufacturing enables efficient, accurate, and patient-specific guided implant rehabilitation after oral cancer surgery, optimizing functional and esthetic outcomes while reducing procedural time and dependence on external providers. Integrating this process into clinical workflows supports personalized treatment planning and broadens access to advanced implant reconstruction within multidisciplinary oncology care. Full article

Background: Resin infiltration has emerged as a micro-invasive strategy for managing enamel porosities, offering both therapeutic and aesthetic benefits. ICON^® (DMG, Hamburg, Germany) is the most widely used system; however, evidence on its penetration behavior in sound enamel remains limited. Objectives: This in vitro study aimed to evaluate the penetration depth and morphological pattern of ICON resin infiltration in sound human enamel, using quantitative morphometric analysis and scanning electron microscopy (SEM). Methods: Fourteen freshly extracted, caries-free anterior teeth were sectioned longitudinally. ICON^® resin infiltrate was applied to the buccal enamel surfaces according to the manufacturer’s protocol, while the lingual/palatal surfaces served as internal controls. Penetration depth was measured quantitatively on both mesial (surface A) and distal (surface B) halves, and SEM was used to assess resin–enamel interface morphology. Statistical analysis included the Shapiro–Wilk test, paired t-test, Pearson correlation, and percentage difference calculation. Results: The mean difference in penetration depth between surfaces A and B was −21.29 µm (p = 0.525), indicating no statistically significant variation. A strong positive correlation was observed between surfaces (r = 0.783, p = 0.001). The mean percentage difference was −3.57% (SD = 18.61%), suggesting minimal directional bias. SEM images confirmed continuous and homogeneous resin infiltration within enamel prisms. Post-hoc power analysis indicated 15.2% power, reflecting the impact of the limited sample size typical for SEM-based exploratory studies. Conclusions: Within the limitations of this in vitro investigation, ICON resin infiltration demonstrated uniform and consistent penetration in sound enamel, supported by both quantitative and SEM analyses. These findings validate its potential as a reliable preventive and micro-invasive biomaterial in dental practice, particularly for protecting enamel surfaces prior to orthodontic bracket bonding. Further clinical research with larger cohorts is recommended to confirm its long-term stability and prophylactic performance. Full article

As a commonly used dental restorative material, light-cured composite resin exhibits mechanical properties that closely match those of natural tooth structure. In the process of biting, the filling material falls off severely due to fretting between the filling material and the fixed interface of the teeth, which shortens the life of the filling material. This study aimed to investigate the mechanisms and contributing factors of this phenomenon. In particular, this study investigated the friction and wear mechanisms at the tangential fretting interface between light-cured composite resin and the tooth substrate under varying fretting amplitudes, normal loads, and lubrication conditions. In artificial saliva, the friction coefficient increased with the fretting amplitude and decreased with the increase in the normal load. The result showed that when the fretting amplitude was large or the normal load was small, the fretting was always in the complete slip regime. When the fretting amplitude was small or the normal load was large, the fretting changed from the complete slip zone to the partial slip regime. The minimum friction coefficient in milk was 0.117, and the maximum friction coefficient in artificial saliva was 0.567. Coke and milk have little effect on the fixation of filling materials. Abrasive wear was the predominant mechanism, with small amplitudes or high loads leading to adhesive wear. The composite resin exhibited the least wear in cola and milk, while soda water and artificial saliva caused significantly greater damage. Full article

Background/Objectives: The clinical application of CAD/CAM restorative materials continues to evolve due to increasing demand for aesthetic, durable, and minimally invasive indirect restorations. Hybrid nanoceramics, such as Grandio disc (VOCO GmbH, Cuxhaven, Germany), are increasingly used in indirect restorative dentistry due to their favourable combination of mechanical strength, polishability, wear resistance, and bonding potential. One challenge associated with adhesive protocols for CAD/CAM materials lies in achieving durable bonds with resin cements. Extensive post-polymerization during fabrication reduces the number of unreacted monomers available for chemical interaction, thereby limiting the effectiveness of traditional adhesive strategies and necessitating specific surface conditioning approaches. This study aimed to evaluate, in a preliminary, non-inferential manner, the influence of several combined conditioning protocols on surface micromorphology, elemental composition, and descriptive SBS trends of a CAD/CAM hybrid nanoceramic. This work was designed as a preliminary pilot feasibility study. Due to the limited number of specimens (two discs per protocol, each providing two independent enamel bonding measurements), all bond strength outcomes were interpreted descriptively, without inferential statistical testing. This in vitro study investigated the effects of various surface conditioning protocols on the adhesive performance of CAD/CAM hybrid nanoceramics (Grandio disc, VOCO GmbH, Cuxhaven, Germany) to dental enamel. Hydrofluoric acid (HF) etching was performed to improve adhesion to indirect resin-based materials using two commercially available gels: 9.5% Porcelain Etchant (Bisco, Inc., Schaumburg, IL, USA) and 4.5% IPS Ceramic Etching Gel (Ivoclar Vivadent, Schaan, Liechtenstein), in combination with airborne-particle abrasion (APA), silanization, and universal adhesive application. HF may selectively dissolve the inorganic phase, while APA increases surface texture and micromechanical retention. However, existing literature reports inconsistent results regarding the optimal conditioning method for hybrid composites and nanoceramics, and the relationship between micromorphology, elemental surface changes, and adhesion remains insufficiently clarified. Methods: A total of ten composite specimens were subjected to five conditioning protocols combining airborne-particle abrasion with varying hydrofluoric acid (HF) concentrations and etching times. Bonding was performed using a dual-cure resin cement (BiFix QM) and evaluated by shear bond strength (SBS) testing. Surface morphology was examined through environmental scanning electron microscopy (ESEM), and elemental composition was analyzed via energy-dispersive X-ray spectroscopy (EDS). Results: indicated that dual treatment with HF and sandblasting showed descriptively higher SBS, with values ranging from 5.01 to 6.14 MPa, compared to 1.85 MPa in the sandblasting-only group. ESEM revealed that higher HF concentrations (10%) created more porous and irregular surfaces, while EDS indicated an increased fluorine presence trend and silicon reduction, indicating deeper chemical activation. However, extending HF exposure beyond 20 s did not further improve bonding, suggesting the importance of protocol optimization. Conclusions: The preliminary observations suggest a synergistic effect of mechanical and chemical conditioning on hybrid ceramic adhesion, but values should be interpreted qualitatively due to the pilot nature of the study. Manufacturer-recommended air abrasion alone may provide limited adhesion under high-stress conditions, although this requires confirmation in studies with larger sample sizes and ageing simulations. Future studies should address long-term durability and extend the comparison to other hybrid CAD/CAM materials and to other etching protocols. Full article

Introduction: Incomplete polymerization of in vivo composite resins (CR) poses a significant problem, with monomer-to-polymer conversion rates ranging from around 60 to 75%. Furthermore, oxygen exposure hampers polymerization in the surface layers. This research aims to evaluate the autophagy-inducing potential of three types of CRS and to explore the role of the Akt/mTOR–autophagy–apoptosis crosstalk in composite resin-induced autophagy. The study uses human gingival fibroblasts and three composite materials (M1 and M2, which are 3D printed, and M3, which is milled). Materials and Methods: SEM analysis was performed on the dental materials, and cells kept in contact for 24 h were subjected to tests including the following: MTT, LDH, NO, immunological detection of proteins involved in autophagy and apoptosis, as well as immunofluorescence tests (Annexin V and nucleus; mitochondria and caspase 3/7; detection of autophagosomes). Results: The results showed statistically significant decreases in cell viability with M1 and M2, linked to increases in cytotoxicity and oxidative stress (LDH and NO). Using multiplex techniques, significant increases in glycogen synthase kinase 3 beta (GSK3b) protein were observed in both M1 and M2; a decrease in mTOR (mechanistic target of rapamycin) expression was noted in M1 and M3. Immunofluorescence tests revealed an increase in Annexin V across all materials studied, and an increase in autophagosomes in M1 and M2, whereas a decrease was observed in M3. Conclusions: The relationship between apoptosis and autophagy is highly complex, indicating they may occur sequentially, coexist, or be mutually exclusive. Understanding this complex interplay can help in designing new 3D-printing protocols and monomer compositions to prevent autophagy imbalance. Full article

Background and Objectives: ACTIVA BioACTIVE Restorative is a resin–ionomer hybrid marketed as a bioactive material for pediatric restorations, yet its specific performance in primary teeth has not been systematically synthesized. The study aim was to evaluate clinical and laboratory outcomes of ACTIVA in primary dentition compared with established restorative materials. Methods: Following a PRISMA-aligned, OSF-registered protocol, PubMed, Scopus, and Web of Science were searched to 18 October 2025 for full-text clinical trials and in vitro studies involving ACTIVA in primary teeth or primary dentin. Eligible designs included randomized or prospective clinical studies and standardized in vitro experiments. Primary outcomes were clinical and radiographic success; secondary outcomes included placement time, shear bond strength, and calcium-ion release. Results: Three randomized clinical trials (86 children, 305 restorations) and one in vitro study met the inclusion criteria. At 12 months, clinical success with ACTIVA ranged from 97.5 to 97.8% versus 95.0–97.8% for bulk-fill and conventional composites. At 24 months, a split-mouth trial reported clinical success of 93.0% for ACTIVA and 95.3% for compomer, with radiographic success of 86.0% and 88.3%, respectively, remaining within the predefined non-inferiority margin. ACTIVA required a mean of 2.4 ± 0.6 min less placement time than compomer. In vitro, shear bond strength to primary dentin was higher for ACTIVA than for an RMGIC (4.29 ± 0.65 vs. 2.47 ± 0.32 MPa), with greater calcium-ion release at 21 days (0.77 ± 0.13 vs. 0.53 ± 0.12 ppm). Conclusions: Within 1–2 years of follow-up, ACTIVA shows clinical performance in primary molars comparable to compomer, bulk-fill, and conventional composites, while offering shorter placement time and favorable bio-interactive behavior. Full article

The consumption of energy and sports drinks is on the rise globally, exposing dental restorations to more frequent low-pH challenges, which affect degradation. This in vitro study simulated the combined effect of energy drink exposure and cyclic fatigue loading on the fatigue survival rate and flexural strength of three direct dental resin restorative materials with distinct chemistries: a bioactive ionic resin (Activa Presto), a giomer (Beautifil Flow Plus F00) and a conventional nano-hybrid composite (Tetric Ceram). Bar-shaped specimens (25 × 2 × 2 mm) were fabricated according to ISO 4049 and stored for 24 h in either distilled water or 0.2 M citric acid (pH ≈ 2.5), simulating an energy drink (n = 10/group). The samples then underwent chewing simulation (40 N, 100,000 cycles, 1.6 Hz) using a steel antagonist; surviving specimens were tested via three-point bending to determine their flexural strength. All the materials were affected by storage conditions: Activa Presto showed the lowest fatigue survival (20% in water; 0% in citric acid), Tetric N-Ceram moderate survival (40% in both solutions) and Beautifil Flow Plus F00 the highest and most stable survival (90% in water; 40% in citric acid). Among the surviving specimens, Tetric Ceram exhibited the highest flexural strength, followed by Beautifil Flow Plus F00 and then Activa Presto. Citric acid exposure and cyclic loading adversely affected the mechanical performance of all the materials within the limitations of this study. Full article

This study aimed to evaluate the effects of thermal cycling and restorative material type on surface roughness of material surfaces and dental interfaces using a non-contact profilometer. Ninety Class V cavities (2 mm × 4 mm × 2 mm in height, width, and depth) were prepared on extracted third molars and restored with four bio-interactive materials (Equia Forte, Cention-N, Activa BioActive Restorative, Fuji II LC) and one composite resin (Solare-X) (n = 18/group). After polishing (Optidisc), initial surface roughness (Sa, µm) was measured following 24 h immersion in distilled water. Measurements were performed at cement/material (400 × 1600 μm²), enamel/material (1600 × 400 μm²), and material surfaces (800 × 800 μm²). Samples underwent 10,000 thermal cycles (5–55 °C) to simulate aging, and roughness was re-measured. Data were analyzed with two-way repeated measures ANOVA and Tukey’s post hoc test (p < 0.05). Solare-X showed the lowest roughness, while Fuji II LC and Activa BioActive Restorative were smoother than Cention-N and Equia Forte (p < 0.01). All materials exhibited significant roughness increases after thermal cycling (p < 0.01). Cement/material and enamel/material interfaces consistently showed higher roughness than material surfaces (p < 0.01). Thermal cycling significantly increased surface roughness of all tested materials. Interfaces demonstrated greater roughness than material surfaces, indicating higher susceptibility to plaque retention and potential risk for long-term restoration success. Full article

This narrative review examines contemporary applications of polymeric materials in dentistry from 2020 to 2025, spanning prosthodontics, restorative dentistry, orthodontics, endodontics, implantology, diagnostics, and emerging technologies. We searched PubMed, Scopus, Web of Science, and Embase for peer reviewed English language articles and synthesized evidence on polymer classes, processing routes, mechanical and chemical behavior, and clinical performance. Approximately 116 articles were included. Polymers remain central to clinical practice: poly methyl methacrylate (PMMA) is still widely used for dentures, high performance systems such as polyether ether ketone (PEEK) are expanding framework and implant-related indications, and resin composites and adhesives continue to evolve through nanofillers and bioactive formulations aimed at improved durability and reduced secondary caries. Thermoplastic polyurethane and copolyester systems drive clear aligner therapy, while polymer-based obturation materials and fiber-reinforced posts support endodontic rehabilitation. Additive manufacturing and computer aided design computer aided manufacturing (CAD CAM) enable customized prostheses and surgical guides, and sustainability trends are accelerating interest in biodegradable or recyclable dental polymers. Across domains, evidence remains heterogeneous and clinical translation depends on balancing strength, esthetics, biocompatibility, aging behavior, and workflow constraints. Full article

The aim of the study was to evaluate the effect of the oxygen-inhibited layer on the bond strength of dental adhesives. The protocol was registered in PROSPERO. PRISMA 2020 guidelines were followed. The focused structured question using Population (P), Intervention (I), Comparison (C), and Outcome (O) was: “What is the effect of oxygen inhibited layer on bonding strength of dental adhesives?” The literature was screened via PubMed, Google Scholar, Scopus, and Web of Science. The last search was carried out in September 2024 with an English language restriction. Two reviewers independently performed screening and evaluation of articles. A total of 71 articles were retrieved from databases, in which only 35 articles were selected for full-text analyses. After implementing the exclusion criteria, eight studies were evaluated and included in the review. The results showed that the presence of an oxygen-inhibited layer led to an increased bond strength when light-cured composite resin was used, but there was a decrease in bond strength and an increased bond failure rate when chemically cured composite was used upon dental adhesive application. Meta-analysis could not be performed due to heterogeneity in the studies. The presence of an oxygen-inhibited layer is beneficial in improving the interfacial bond strength when used with light-cured composite resin (when light curing was performed in accordance with the manufacturer’s instructions). Full article

Background: Digital indirect bonding (IB) has emerged as a reliable approach to improving the precision and efficiency of orthodontic bracket placement. Methods: This in vitro study evaluated and compared the positional accuracy and efficiency of two digitally driven indirect bonding (IB) techniques—a rigid single-tooth transfer jig (Leone Jig System) and a flexible three-part transfer tray (IBT Flex Resin)—as well as conventional direct bonding. Ten sets of 3D-printed resin dental models were randomly allocated to the three bonding protocols. Bracket positions were virtually planned and analyzed by superimposing pre- and post-bonding STL models using landmark- and surface-based registration. Linear discrepancies were measured along the axial, sagittal, and vertical planes, and data were analyzed using repeated-measures ANOVA and Friedman tests (α = 0.05). Results: Both indirect bonding techniques showed significantly smaller deviations from the ideal virtual setup compared with direct bonding across all spatial planes (p < 0.001). Mean discrepancies were consistently below 0.3 mm for the indirect protocols, compared with values exceeding 0.4 mm for direct bonding. The rigid jig demonstrated the highest precision, particularly in the sagittal (0.18 ± 0.06 mm) and vertical (0.21 ± 0.07 mm) planes, while the flexible tray showed slightly higher deviations (approximately 0.25–0.30 ± 0.08–0.09 mm across planes). Chairside bonding time per full arch was reduced by more than 50% with both IB techniques, with the jig-based system being the most time-efficient. No significant interaction between bonding method and spatial plane was observed. Conclusions: Within the limitations of this in vitro study, digital indirect bonding—especially rigid, patient-specific jigs—demonstrated superior bracket placement accuracy and procedural efficiency compared with direct bonding. Full article

The development of dental restorative materials with improved physical and mechanical properties is an important area of research. In this study, hexaallylaminocyclotriphosphazene (HAP) was used to modify dental composites. HAP is a compound with multiple carbon-carbon bonds that can react with methacrylic resins to form a copolymer. HAP was synthesized by reacting allylamine with hexachlorocyclotriphosphazene and characterized it using ¹H and ³¹P NMR spectroscopy and MALDI-TOF mass spectrometry. Molecular dynamics simulations using the MM2 force field showed that HAP has a nanosize (the diameter of a sphere eclosing the molecule is 1.3 nm), making it a suitable nanomodifier for dental composites. Using 3D printing, samples of dental methacrylic composites containing up to 10 wt. % HAP were prepared and their physicomechanical properties and antibacterial activity against gram-positive bacteria S. mutans were studied. As a result, it was established that the maximum flexural strength (115.1 ± 10.2 MPa) is achieved with a modifier content of 5 wt.% in the composite. The maximum value of inhibition of S. mutans growth in a liquid nutrient medium is achieved with a HAP content of 10 wt.% in the sample. Furthermore, with a HAP content of more than 5 wt.% in the composite, inhibition of biofilm on the material surface is observed. The resulting composite is proposed for use as dental crowns in restorative dentistry. Full article

This study evaluated the push-out bond strength (PBS) and failure modes of fiber posts cemented with silane-containing self-adhesive resin cement (SARC) compared with conventional SARC and universal adhesive strategies, considering the effects of root section and aging. Ninety single-rooted human premolars were equally assigned to three cementation protocols: silane-containing SARC (PANAVIA SA Cement Universal), conventional SARC (RelyX Universal), and universal adhesive plus SARC (Scotchbond Universal Plus + RelyX Universal). Each group was divided into two aging subgroups: 24 h water storage and thermal cycling (10,000 cycles between 5 °C and 55 °C, 30 s dwell time; n = 15). After root canal treatment and post space preparation, glass fiber posts were cemented, and each root was sectioned to obtain six slices. PBS was measured using a push-out test, and failure modes were examined under stereomicroscopy. Data were analyzed using three-way ANOVA, post hoc tests, Spearman’s correlation, and logistic regression (α = 0.05). Cement type, root section, and aging significantly influenced PBS (p < 0.001). PBS decreased from coronal to apical sections, and thermal cycling reduced PBS in all groups. The universal adhesive plus SARC achieved the highest PBS, while conventional SARC had the lowest PBS. Cementdentin adhesive failures (FM2) predominated overall, with proportions varying between 43% and 90%, and higher PBS values were associated with fewer FM2 failures. The combination of a universal adhesive with SARC provided superior bonding compared to simplified protocols. Although silane-containing SARC improved bonding relative to conventional SARC, durable adhesion to radicular dentin remains challenging, particularly in apical regions. Full article