Dentistry Journal最新文献

Background: Nickel-titanium (NiTi) endodontic instruments have undergone significant improvements in heat treatment processing and geometric design, aimed at enhancing flexibility, cutting efficiency, and fatigue strength. Reciprocating motion was introduced to increase cyclic fatigue resistance, which remains the predominant mode of failure in NiTi endodontic file systems. Although these instruments are widely used in both clinical practice and research, few comparative studies have integrated geometric, metallurgical and mechanical evaluations of the most commonly used reciprocating systems. Methods: In the present study, four single-file reciprocating NiTi systems (Reciproc Blue, WaveOne Gold, EdgeOne Fire, and Easy-File Flex) were evaluated for their geometric design, metallurgical composition, and cyclic fatigue strength. Stereomicroscopy and scanning electron microscopy were employed to assess active blade length, spiral configuration, and surface finish, while elemental composition and phase transformation temperatures were analyzed using energy-dispersive X-ray spectroscopy and differential scanning calorimetry. Ten instruments from each group were tested for cyclic fatigue using a standardized curved stainless-steel canal at room temperature, and the time to fracture was recorded. Fatigue data were statistically analyzed using Mood's median test, with significance set at p < 0.05. Results: Reciproc Blue exhibited the longest active blade length, highest spiral density, and superior surface finish. R-phase start and finish temperatures were highest in WaveOne Gold and lowest in Easy-File Flex. Reciproc Blue demonstrated the higher cyclic fatigue strength, whereas Easy-File Flex showed the lowest. Conclusions: These findings suggest that the metallurgical and geometric characteristics of the Reciproc Blue file significantly enhance its strength to cyclic fatigue compared with the other instruments evaluated.

Background/Objectives: Dental caries remains one of the most prevalent chronic diseases worldwide, making enamel remineralization a key objective in minimally invasive dentistry. This in vitro study compared the remineralization efficacy of five therapeutic toothpastes containing fluoride, NovaMin, CPP-ACP, nano-hydroxyapatite, arginine, and xylitol. Methods: Sixty enamel specimens were prepared from extracted human posterior teeth and artificially demineralized. Samples were randomly allocated into six groups (n = 10): one negative control (C1) stored in artificial saliva and five treatment groups (P1-P5). A 28-day remineralization protocol with twice-daily applications was performed. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to assess surface morphology and elemental composition (Ca, P, F, Na, O, Ca/P ratio) at days 1, 14, and 28. Vickers microhardness testing was used to evaluate changes in mechanical properties. Statistical analysis included one-way ANOVA, repeated measures ANOVA, Tukey's post hoc test, and Kruskal-Wallis where appropriate (α = 0.05). Results: All therapeutic toothpastes produced some increase in mineral content compared to the demineralized control. At day 28, significant intergroup differences were observed for calcium, phosphorus, and fluoride (p < 0.001). The arginine-fluoride formulation (P4) and the NovaMin-based formulation (P3) showed the most consistent increases in Ca and P, with SEM revealing the formation of a continuous, compact surface layer and marked reduction in prismatic porosities. Fluoride-containing toothpastes (P1, P3, P4) showed significant fluoride incorporation (p < 0.001 vs. control). The nano-hydroxyapatite/xylitol prototype (P5) produced a delayed but progressive increase in Ca and P, with partial filling of prismatic spaces. The CPP-ACP-based toothpaste (P2) led to limited changes, with only slight differences vs. control at day 28. Vickers microhardness values increased significantly in groups P1, P3, P4, and P5 (p < 0.05), in agreement with the higher mineral levels found in these samples. Conclusions: Under the present in vitro conditions, toothpastes containing fluoride in combination with NovaMin or arginine, as well as nano-hydroxyapatite/xylitol, demonstrated the highest remineralization potential under the present in vitro conditions, both chemically and mechanically. Xylitol-based formulations without a direct mineral supply showed limited effects. The pH and active composition of the toothpaste strongly influenced enamel remineralization outcomes.

Background/Objectives: Multilayer zirconia restorations can feature a shade gradient or a strength gradient, with layers differing in color or phase composition within the same material. The aim of this in vitro study was to evaluate the color stability in all layers of multilayer zirconia after exposure to staining solutions and artificial aging. Methods: Square-shaped specimens (N = 120) of color A2 were fabricated from 4Y-PSZ and 3Y/4Y-PSZ multilayer zirconia-Katana STML, DD Cube One ML, and Katana YML-and their baseline color values (T0) were measured with a clinical spectrophotometer (VITA Easyshade V). The specimens were randomly divided into four groups (n = 10/gp) and immersed in physiologic solution, 0.2% chlorhexidine gluconate (CHX) mouth rinse, and staining coffee solution. Then, they were measured continuously for 7 (T1), 14 (T2), and 21 days (T3). The last group of specimens underwent accelerated aging in a steam autoclave at 134 °C and 2 bar pressure and measured after 1 (T1), 3 (T2), and 5 h (T3). After the immersion process and artificial aging, discoloration values (ΔE) were calculated using the formula ΔE = [(ΔL*)² + (Δa*)² + (Δb*)²]^1/2 and analyzed with the SPSS v 23.0 software with a p value < 0.05. Results: All specimens showed significant color differences in the T3 measurements after exposure to coffee and CHX, with the highest ΔE values in the enamel layers. Katana YML showed the most significant differences in ΔE in the cervical layers after exposure to artificial aging. Conclusions: Multilayer zirconia exhibited dependent optical changes, with the enamel layers being the most affected after exposure to staining solutions. Gradient pigmentation and differences in phase composition caused differences in color to the multilayer zirconia layers after exposure to staining solutions and artificial aging.

Background/Objectives: Anaphylaxis is a rare occurrence in dental practice, yet when it happens, it demands swift management, as untreated cases can be fatal. The aim of this study is to evaluate the level of knowledge among dental students and residents regarding the symptoms and management of anaphylactic emergencies in dental surgery. Methods: The study involved a sample of 236 students from the 3rd and 5th years, and residents in their 1st and 2nd years of the General Dentistry programme at the Faculty of Dental Medicine in Iași, Romania. The response rate to the invitation was 85.8%. Knowledge was assessed using a self-administered questionnaire consisting of 18 questions organised into three sections, which were tested for internal consistency, yielding a Cronbach's alpha value of 0.731. Results: Statistically significant differences in the responses provided by the three categories of participants were observed for the following items: management of patients with an allergic background (p = 0.033), factors aggravating allergic predisposition (p = 0.001), the correct dose of epinephrine (p = 0.001), secondary medication (p = 0.001), and the timing of treatment initiation (p = 0.009). Questions where answers indicated moderate to low levels of knowledge (25-50% correct answers) concerned the therapeutic approach for patients with an allergic background, the site of adrenaline administration, and secondary medication. Conclusions: Overall, it can be observed that students demonstrated a high level of knowledge in questions related to the symptomatology of anaphylaxis and the therapeutic management of allergic patients, whereas residents showed better performance in questions addressing the therapeutic management of anaphylaxis. However, significant knowledge gaps were identified across all participant categories, suggesting that there must be periodic supplementary training.

Background/Objectives: Light-curing dental resin composites remain limited by high polymerization shrinkage, inadequate wear resistance, and elevated water sorption. The combined influence of filler shape, size, and loading level on mechanical performance and hydrolytic stability remains insufficiently understood. This study aimed to systematically investigate the effects of filler morphology and particle size distribution on the key properties of dental composites. Methods: Spherical silica (SiO₂) nanoparticles (D50 = 0.50 μm) were synthesized via the Stöber method, while irregular aluminosilicate glass was used in coarse (D50 = 3.71 μm) and fine (D50 = 1.98 μm) fractions. Three composite groups were formulated: Group 1 (72 wt.% filler with 0-30% SiO₂), Group 2 (maximum filler loading 76-80 wt.% with 10-30% SiO₂), and Group 3 (74.5 wt.% filler with varying coarse/fine glass ratios). Flexural strength, flexural modulus, Vickers microhardness, depth of cure, water sorption, and solubility were evaluated according to ISO 4049:2019. Results: Incorporation of spherical SiO₂ nanoparticles significantly reduced composite viscosity, enabling maximum filler loading to increase from 72 to 80 wt.%. All composites exceeded ISO requirements for flexural strength (80.54-118.11 MPa), depth of cure (3.01-5.65 mm), water sorption (14.61-22.87 μg/mm³), and solubility (1.20-5.90 μg/mm³). The highest flexural strength (118.11 ± 10.54 MPa) and modulus (9.26 ± 1.12 GPa) were achieved at 78 wt.% filler loading. Bimodal glass systems (50/50 ratio) demonstrated optimal mechanical properties, while higher fine fractions reduced strength. Conclusions: Spherical SiO₂ nanoparticles effectively reduce viscosity and enable higher filler loading. The optimal balance between filler loading, particle shape, and size distribution should be tailored to clinical requirements, with high-strength formulations suited for posterior restorations and bimodal formulations for universal applications.

Background: Burning Mouth Syndrome (BMS) is a chronic orofacial pain condition characterized by a burning sensation in the oral cavity without identifiable lesions. It predominantly affects women (especially postmenopausal) but can occur in men. BMS is considered a multifactorial neuropathic pain disorder involving both peripheral small-fiber neuropathy and central dysregulation, often accompanied by taste alterations (dysgusia) and xerostomia despite normal oral exams. Treatment is challenging, with modest responses to agents like clonazepam, tricyclic antidepressants, or gabapentinoids. Observations: We present a 67-year-old male with recalcitrant primary BMS who showed complete remission temporally associated with occipital nerve blockade, likely affecting central trigeminocervical pathways. Initial therapy with amitriptyline (25 mg) and gabapentin (900 mg/day) yielded ~30% pain relief. Given suspected central sensitization, greater and lesser occipital nerve (GON) blocks were administered in series. After the first, second, and third ON blocks, pain was reduced by ~50%, 80%, and 100%, respectively. Remission persisted at one-year follow-up under continued medications. A mild recurrence (~20% of baseline pain) responded fully to a fourth GON block, maintaining another year of pain-free status. Lessons: This case underscores the complex central mechanisms in BMS and illustrates that modulating central pain circuits via occipital nerve blockade, through trigeminocervical convergence mechanisms, without direct trigeminal intervention. We discuss the diagnostic challenges of BMS, the rationale of occipital neuromodulation, and how this novel therapeutic strategy compares with current literature, supporting the hypothesis of central sensitization in BMS.

Background: The aim of this study is to investigate the potential link between the use of specific medications and oral adverse drug reactions. Methods: The 100 most frequently prescribed drugs in Germany in 2023 were compiled using the "PharMaAnalyst" database. According to the descriptions of adverse drug reactions (ADRs) in the patient information leaflets the ADRs were selected, analyzed and weighted with scores according to a classification system that distinguishes four groups of ADRs by frequency: 'very common' (4), 'common' (3), 'uncommon' (2) and 'rare' (1). The objective was to summarize the scores of the oral ADRs and define the 'oral side effect score' (OSES). Results: After accounting for duplication due to various brand names, 49 medications were reviewed. A total of 65% of the medications exhibited oral ADRs. The number of oral ADRs per medication ranged from one to seven. Xerostomia and dysgeusia were the most prevalent oral side effects, accounting for 37% of cases. Overall, 34% of side effects were classified as either 'very common' or 'common'. The medication groups with the highest OSES were antidepressants, antibiotics and analgesics. Of the individual medications, azithromycin, gabapentin and pregabalin exhibited the highest OSES. Conclusions: This study provides a comprehensive overview of oral side effects associated with the 100 most frequently prescribed drugs. Patients with polypharmacy are particularly likely to experience oral side effects such as xerostomia and dysgeusia. Due to their high OSES combinations, antibiotics, analgesics or antidepressants may trigger multiple oral ADRs. It is essential that the medical community is continuously updated on pharmacological knowledge to raise awareness of oral ADRs.

Objective: This study aimed to compare the accuracy of two large language models (LLMs)-ChatGPT (version 3.5) and Google Gemini (formerly Bard)-in answering dental caries-related multiple-choice questions (MCQs) using a simulated student examination framework across seven examination lengths. Materials and Methods: A total of 125 validated dental caries MCQs were extracted from Dental Decks and Oxford University Press question banks. Seven examination groups were constructed with varying question counts (25, 35, 45, 55, 65, 75, and 85 questions). For each group, 100 simulations were generated per LLM (ChatGPT and Gemini), resulting in 1400 simulated examinations. Each simulated student received a unique randomized subset of questions. MCQs were answered by each LLM using a standardized prompt to minimize ambiguity. Outcomes included mean score, passing rate (≥60%), and performance differences between LLMs. Statistical analyses included independent t-tests, one-way ANOVA within each LLM, and two-way ANOVA examining interactions between LLM type and question count. Results: Across all seven examination formats, Gemini significantly outperformed ChatGPT (p < 0.001). Gemini achieved higher passing rates and higher mean scores in every examination length. One-way ANOVA revealed significant score variation with increasing exam length for both LLMs (p < 0.05). Two-way ANOVA demonstrated significant main effects of LLM type and question count, with no significant interaction. Randomization had no measurable effect on Gemini performance but influenced ChatGPT scores. Conclusions: Gemini demonstrated superior accuracy and higher passing rates compared to ChatGPT in all simulated examination formats. While both LLMs struggled with complex caries-related content, Gemini provided more reliable performance across question quantities. Educators should exercise caution in relying on LLMs for automated assessment or self-study, and future research should evaluate human-AI hybrid models and LLM performance across broader dental domains.

Introduction: Antibiotics are routinely prescribed for odontogenic abscesses in emergency departments and dental offices. Augmentin is recommended for moderate to severe dentofacial infections. It is usually prescribed in two popular regimens, namely twice (bid) or three times (tid) per day. The aim of this study was to compare the efficacy of two different formulations of amoxicillin-clavulanate, 875/125 mg bid versus 500/125 mg tid, for the treatment of acute dental apical abscesses with orofacial involvement. Methods: Sixty-one patients with acute apical abscesses were prescribed Augmentin in either an 875/125 mg bid or 500/125 mg tid formulation. The patients were tested for inflammatory markers upon admission and again after 72 h. Results: Although all patients experienced a decrease in inflammatory markers over 72 h of antibiotic therapy, there was a statistically significant greater decrease in white blood cells and neutrophils in the patients receiving the 500/125 mg tid regimen. Conclusions: A 500/125 mg tid Augmentin regimen results in a greater decline in inflammatory markers than 875/125 mg bid over 72 h in the setting of dentofacial infection.

Background: Systemic bone loss, particularly osteoporosis, and periodontal disease are highly prevalent chronic conditions that share common risk factors and biological pathways. Increasing evidence suggests a bidirectional relationship between these conditions; however, findings remain heterogeneous and evolving. Objective: This review aims to evaluate and update current evidence on the bidirectional association between systemic bone loss and periodontal disease, with emphasis on underlying mechanisms and clinical implications. Methods: A narrative review of the literature was conducted using major electronic databases, focusing on human studies evaluating the relationship between osteoporosis or systemic bone loss and periodontal disease. Relevant experimental, clinical, and epidemiological studies were included. Results: Most studies support an association between reduced bone mineral density and increased severity of periodontal disease, including greater alveolar bone loss and attachment loss. Conversely, periodontal inflammation may contribute to systemic bone remodeling through inflammatory mediators. However, variability in study design, diagnostic criteria, and confounding factors limits definitive conclusions. Conclusions: Current evidence supports a bidirectional association between systemic bone loss and periodontal disease. Greater interdisciplinary awareness is warranted, and future well-designed longitudinal studies are needed to clarify causality and inform preventive and therapeutic strategies.