Search Results (255)

Background/Objectives: The expansion of National Health Insurance (NHI) coverage for dental implants in South Korea has substantially increased implant placements among older adults. While implants offer functional and esthetic benefits, their lack of periodontal ligaments alters occlusal force distribution, potentially increasing biomechanical stress on adjacent or opposing teeth. This study aimed to investigate the association between the increased number of dental implants and the incidence of cracked teeth following the introduction of implant insurance. Methods: A retrospective analysis was conducted using the Clinical Data Warehouse of Seoul St. Mary’s Dental Hospital. Patients who underwent molar crown restorations between 2014 and 2022 were included. The incidence and clinical features of cracked teeth were compared before (2014–2015) and after (2016–2022) the introduction of implant insurance. Statistical analyses assessed differences in symptom presentation, pulp status, and treatment outcomes. Results: Among 5044 molars restored with crowns, 1692 were diagnosed with cracks. The incidence of cracked teeth significantly increased after NHI coverage for implants (25.5% vs. 32.6%, p < 0.001). Cases after insurance implementation showed fewer signs and symptoms at initial presentation (67.4% vs. 50.0%, p < 0.001), reduced irreversible pulpitis (37.2% vs. 25.8%, p < 0.001), and increased preservation of pulp vitality (46.9% vs. 57.8%, p < 0.001). These shifts may reflect changes in occlusal adjustment practices and earlier clinical intervention. Conclusions: The findings suggest a temporal link between increased implant placement and the rising incidence of cracked teeth. Implant-induced occlusal changes may contribute to this trend. Careful occlusal evaluation and follow-up are essential after implant placement, and further prospective studies are warranted to confirm causality and refine prevention strategies. Full article

Background/Objectives: Dental practitioners widely use dental implants to treat traumatic cases. Titanium implants are currently the most popular choice among dental practitioners and surgeons. The discovery of newer polymeric materials is also influencing the interest of dental professionals in alternative options. A comparative study between existing titanium implants and newer polymeric materials can enhance professionals’ ability to select the most suitable implant for a patient’s treatment. This study aimed to investigate material property advantages of high-performance thermoplastic biopolymers such as PEEK and PEKK, as compared to the time-tested titanium implants, and to find the most suitable and economically fit implant material. Methods: Three distinct implant material properties were assigned—PEEK, PEKK, and commercially pure titanium (CP Ti-55)—to dental implants measuring 5.5 mm by 9 mm, along with two distinct titanium (TI6AL4V) abutments. Twelve three-dimensional (3D) models of bone blocks, representing the mandibular right molar area with Osseo-integrated implants were created. The implant, abutment, and screw were assumed to be linear; elastic, isotropic, and orthotropic properties were attributed to the cancellous and cortical bone. Twelve model sets underwent a three-dimensional finite element analysis to evaluate von Mises stress and total deformation under 250 N vertical and oblique (30 degree) loads on the top surface of each abutment. Results: The study revealed that the time-tested titanium implant outperforms PEEK and PEKK in terms of marginal bone preservation, while PEEK outperforms PEKK. Conclusions: This study will assist dental practitioners in selecting implants from a variety of available materials and will aid researchers in their future research. Full article

Background: This study aimed to assess the impact of methacrylate-functionalized polyhedral oligomeric silsesquioxanes dispersed in nanosilica (MA/Ns-POSS) on the mechanical properties of light-curable dental resins and composites. The primary goal was to evaluate how different concentrations of MA/Ns-POSS (0.5–20 wt.%) affect the hardness, flexural strength, modulus, diametral tensile strength, polymerization shrinkage stress, and degree of conversion of these materials. Methods: A mixture of Bis-GMA, UDMA, TEGDMA, HEMA, and camphorquinone, with a tertiary amine as the photoinitiator, was used to create resin and composite samples, incorporating 45 wt.% silanized silica for the composites. Hardness (Vickers method, HV), flexural strength (FS), and flexural modulus (E_f) were assessed using three-point bending tests, while diametral tensile strength (DTS) polymerization shrinkage stresses (PSS), and degree of conversion (DC) analysis were analyzed for the composites. Results: The results showed that resins with 10 wt.% MA/Ns-POSS exhibited the highest E_f and FS values. Composite hardness peaked at 20 wt.% MA/Ns-POSS, while DTS increased up to 2.5 wt.% MA/Ns-POSS but declined at higher concentrations. PSS values decreased with increasing MA/Ns-POSS concentration, with the lowest values recorded at 15–20 wt.%. DC analysis also showed substantial improvement for 15–20 wt.% Conclusion: Incorporating MA/Ns-POSS improves the mechanical properties of both resins and composites, with 20 wt.% showing the best results. Further studies are needed to explore the influence of higher additive concentrations. Full article

Students, particularly those in the medical field, are exposed to various stressors that can affect their health-related behaviors, including smoking habits, with implications for oral health and quality of life. Background and Objectives: to analyze the relationship between smoking, oral health, perceived stress level, and self-assessed quality of life in a sample of dental students. Materials and Methods: The cross-sectional study included 338 students, who completed validated questionnaires and were clinically examined. Lifestyle was assessed using a smoking behavior questionnaire, stress levels were measured with the Student Stress Inventory (SSI), and quality of life was evaluated using the EQ-5D-5L instrument. The DMFT index was calculated to determine oral health status. Results: Among the 338 participating students, 53.8% were smokers. The lifestyle analysis revealed slightly higher average scores among non-smokers across all domains—social (3.26 vs. 3.09), attitudinal (2.75 vs. 2.97), and behavioral (3.82 vs. 3.49), but without statistically significant differences (p > 0.25). The mean DMFT score was 12.48, with no significant differences between smokers and non-smokers (p = 0.554). The SSI total score averaged 83.15, indicating a moderate level of perceived stress, again with no statistically significant differences between the groups (p > 0.05). However, slightly higher average stress scores among smokers may suggest the use of smoking as a coping mechanism. In contrast, quality of life as measured by EQ-5D-5L showed significantly worse outcomes for smokers across all five dimensions, including mobility (78.6% vs. 95.5%, p = 0.000) and self-care (93.4% vs. 100%, p = 0.001). Multivariable logistic regression identified smoking (OR = 1.935; p = 0.047) and moderate stress levels (OR = 0.258; p < 0.001) as independent predictors of oral health status. Conclusions: The results obtained suggest that smoking may function as a stress management strategy among students, supporting the relevance of integrating specific psychobehavioral interventions that address stress reduction and oral health promotion among student populations. Full article

A novel macrodesign for a dental implant characterized by a non-monotonic variation in core diameter and thread shape has been described to produce lower stress levels during insertion as compared to conventional tapered implants. Two finite element models resembling the lower left molar region with preformed osteotomies were created based on a cone beam computed tomography (CBCT) scan. Insertion of both the novel and the conventional, tapered implant type were simulated using Standard for the Exchange of Product model data (STEP) files of both implant types. Von Mises equivalent stress, strain development, and amount of redistributed bone were recorded. The conventional implant demonstrated a continuous increase in strain values and reaction moment throughout the insertion process, with a brief decrease observed during the final stages. Stress levels in the cortical bone gradually increased, followed by a reduction when the implant was finally positioned subcrestally. The novel implant achieved the maximum magnitude of reaction moment and cortical bone strain values when the implant’s maximum core diameter passed the cortical bone layer at around 60% of the insertion process. Following a notable decrease, both the reaction moment and stress started to rise again as the implant penetrated further. The novel implant removed more bones in the trabecular region while the conventional implant predominantly interacted with cortical bone. Overall, the novel design seems to be less traumatic to alveolar bone during the insertion process and hence may lead to reduced levels of initial peri-implant bone loss. Full article

The design of custom abutments (CA) can affect the mechanical reliability of implant-supported restorations. The purpose of the study was to evaluate the influence of design parameters on the fatigue limit of CA and to compare optimized custom designs with the reference abutment (RA). A morse-tapered dental implant, an anatomical abutment, and a connector screw were digitalized using microcomputed tomography. A cone beam computed tomography scan was obtained from one of the authors to virtually place the implant-abutment assembly in the upper central incisor. Ten design parameters were selected according to the structural geometry of the RA and the implant planning. A reverse-engineered RA model was created in SOLIDWORKS and was modified considering a Taguchi orthogonal array to generate 36 CAs with ±20% dimensional variations. Finite element analysis was conducted in ABAQUS, and fatigue limits were estimated using Fe-safe. ANOVA (α = 0.1) identified the most influential parameters. Von Mises stress values ranged from 229 MPa to 302 MPa, and 94.4% of the CAs had a higher fatigue limit than the RA. Three parameters significantly affected the fatigue performance of the implant system. The design process of custom abutments includes critical design parameters that can be optimized for longer lifetimes of implant-abutment restorations. Full article

This study presents a methodology for developing and validating digital models of tooth-inlay systems, aiming to trace the complete workflow from clinical procedures to simulation by involving dental professionals—dentists for manual cavity preparation and dental technicians for restoration modelling—while integrating micro-computed tomography (micro-CT) imaging with finite element analysis (FEA). The proposed workflow includes (1) the acquisition of high-resolution 3D micro-CT scans of a non-restored tooth, (2) image segmentation and reconstruction to create anatomically accurate digital twins and mesh generation, (3) the selection of proper resin and the 3D printing of four typodonts, (4) the manual preparation of cavities on the typodonts, (5) the acquisition of high-resolution 3D micro-CT scans of the typodonts, (6) mesh generation, digital inlay and onlay modelling and material property assignment, and (7) nonlinear FEA simulations under representative masticatory loading. The approach enables the visualisation of stress and deformation patterns, with preliminary results indicating stress concentrations at the tooth-restoration interface integrating different cavity alternatives and restorations on the same tooth. Quantitative outputs include von Mises stress, strain energy density, and displacement distribution. This study demonstrates the feasibility of using image-based, tooth-specific digital twins for biomechanical modelling in dentistry. The developed framework lays the groundwork for future investigations into the optimisation of restoration design and material selection in clinical applications. Full article

Palm oil is a highly versatile natural resource that has gathered significant attention due to its bioactive properties, particularly its antimicrobial and antioxidant effects. Rich in tocotrienols, tocopherols, and carotenoids, palm oil exhibits potent antioxidant activity, while its fatty acid content and other bioactive molecules contribute to its antimicrobial efficacy against various pathogens. The underlying mechanisms of action driving these bioactivities involve intricate molecular interactions, biochemical pathways, and redox processes, which influence microbial cell function and oxidative stress reduction. This review provides a critical analysis of the current mechanistic understanding of palm oil’s biofunctional properties, emphasizing its potential incorporation into engineered biomaterials. Particular focus is given to the chemical composition, reaction pathways, and synergistic potential of palm oil derivatives in material-based formulations. Furthermore, the potential applications of palm oil as a standalone or synergistic agent in novel therapeutic and industrial formulations are explored. By elucidating the mechanistic basis of its bioactivity within material contexts, this review highlights palm oil’s promising role in the development of advanced functional materials for pharmaceutical and dental technologies. Full article

Background: Burnout syndrome (BS) is an occupational condition resulting from chronic stress, characterized by three dimensions, emotional exhaustion (EE), depersonalization (DE), and diminished personal accomplishment (PA), particularly prevalent in caregiving professions such as healthcare. The aim of this study is to analyse the prevalence of BS among Spanish dental implantology specialists, along with the impact of demographic, educational, and professional aspects. Methods: This is a cross-sectional observational study based on the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines and was open to respondents from May to December 2024. An electronic survey based on the Maslach Burnout Inventory—Human Services Survey (MBI–HSS) was sent to members of the Spanish Society of Implants. The data were analysed using descriptive analysis. Results: A total of 305 participants (20.9%) (31.5% females and 68.5% males) completed the questionnaire. The prevalence of BS was 4.3%; however, 61.0% of the dentists showed signs of suffering from the syndrome. The mean values of EE were “average” (20.3 ± 13.8) and of DE and EE “low” (5.1 ± 5.9, and 32.5 ± 14.5, respectively). The factors significantly associated with suffering from BS were being female and having more than 20 years of experience in dental implant treatments. Conclusions: It is advisable to conduct instructive and awareness-raising initiatives among dental professionals to promote an awareness of their mental health, ultimately aiming at preserving their physical and emotional well-being while delivering optimal care to their patients. Full article

Optimizing stress distribution at the bone–implant interface is critical to enhancing the long-term biomechanical performance of dental implant systems. Vertical misalignment between splinted implants can result in elevated localized stresses, increasing the risk of material degradation and peri-implant bone resorption. This study employs three-dimensional finite element analysis (FEA) to evaluate the mechanical response of peri-implant bone under oblique loading, focusing on how variations in vertical implant platform alignment influence stress transmission. Four implant configurations with different vertical placements were modeled: (A) all crestal, (B) central subcrestal with lateral crestal, (C) lateral subcrestal with central crestal, and (D) all subcrestal. A 400 N oblique load was applied at 45° simulated masticatory forces. Von Mises stress distributions were analyzed in both cortical and trabecular bone, with a physiological threshold of 100 MPa considered for cortical bone. Among the models, configuration B exhibited the highest cortical stress, exceeding the physiological threshold. In contrast, configurations with uniform vertical positioning, particularly model D, demonstrated more favorable stress dispersion and lower peak values. Stress concentrations were consistently observed at the implant–abutment interface across all configurations, identifying this area as critical for design improvements. These findings underscore the importance of precise vertical alignment in implant-supported restorations to minimize stress concentrations and improve the mechanical reliability of dental implants. The results provide valuable insights for the development of next-generation implant systems with enhanced biomechanical integration and material performance under functional loading. Full article

Background/Objectives: Dental cavity preparation is a critical procedure in restorative dentistry that involves the removal of decayed tissue while preserving a healthy tooth structure. Excessive stress during tooth preparation leads to enamel cracking, dentin damage, and long term compressive pulp health. This study employed finite element analysis (FEA) to investigate the stress distribution in dental structures during cavity preparation using round diamond burs of varying diameters and depths of cut (DOC). Methods: A three-dimensional human maxillary first molar was generated from computed tomography (CT) scan data using 3D Slicer, Fusion 360, and ANSYS Space Claim 2024 R-2. Finite element analysis (FEA) was conducted using ANSYS Workbench 2024. Round diamond burs with diameters of 1, 2, and 3 mm were modeled. Cutting simulations were performed for DOC of 1 mm and 2 mm. The burs were treated as rigid bodies, whereas the dental structures were modeled as deformable bodies using the Cowper–Symonds model. Results: The simulations revealed that larger bur diameters and deeper cuts led to higher stress magnitudes, particularly in the enamel and dentin. The maximum von Mises stress was reached at 136.98 MPa, and dentin 140.33 MPa. Smaller burs (≤2 mm) and lower depths of cut (≤1 mm) produced lower stress values and were optimal for minimizing dental structural damage. Pulpal stress remained low but showed an increasing trend with increased DOC and bur size. Conclusions: This study provides clinically relevant guidance for reducing mechanical damage during cavity preparation by recommending the use of smaller burs and controlled cutting depths. The originality of this study lies in its integration of CT-based anatomy with dynamic FEA modeling, enabling a realistic simulation of tool–tissue interaction in dentistry. These insights can inform bur selection, cutting protocols, and future experimental validations. Full article

Background/Objectives: The increasing demand for aesthetics in dentistry has driven significant advancements in both materials and techniques. The primary cause of ceramic detachment in dental restorations is extensive mechanical stress, which often results in detachment and clinical complications. This study aims to improve the bond strength between NiCr-based metal frameworks and ceramic coatings by introducing biocompatible inorganic MeSiON thin films (Me = Cr or Zr) as interlayers. Methods: MeSiON coatings with a thickness of ~2 μm were deposited on NiCr alloy using cathodic arc evaporation. To tailor the stoichiometry, morphology, and mechanical properties of the coatings, the substrate bias voltage was varied: −50 V, −100 V, −150 V, −200 V. Structural and surface characterization was performed using SEM/EDS, XRD, profilometry, and contact angle analysis. The coating adhesion was evaluated by using standardized scratch testing, while the bond strength was evaluated using a three-point bending test. Results: The NiCr alloy exhibited a dendritic microstructure, and the ceramic layer consisted mainly of quartz, feldspar, kaolin, and ZrO₂. ZrSiON coatings showed superior roughness, elemental incorporation, and adhesion compared to Cr-based coatings, these properties being further improved by increasing the substrate bias. The highest bond strength was achieved with a ZrSiON coating deposited at −200 V, a result we attributed to increased surface roughness and mechanical interlocking at the ceramic-metal interface. Conclusions: CrSiON and ZrSiON interlayers enhanced ceramic-to-metal adhesion in NiCr-based dental restorations. The enhancement in bond strength is primarily ascribed to substrate bias-induced modifications in the coating’s stoichiometry, roughness, and adhesion. Full article

Using ultra-short dental implants is a promising alternative to extensive bone grafting procedures for patients with atrophic posterior mandibles and vertical bone loss. However, the amount of insertion torque (IT) applied during implant placement significantly influences stress distribution in the peri-implant bone, which affects implant stability and long-term success. Materials and Methods: This study used finite element analysis (FEA) to examine how different insertion torques (35 N·cm and 75 N·cm) affect stress distribution in cortical and trabecular bone types D2 and D4 surrounding ultra-short implants. Von Mises equivalent stress values were compared with ultimate bone strength thresholds to evaluate the potential for microdamage during insertion. Results: The findings demonstrate that increasing IT from 35 N·cm to 75 N·cm led to a significant increase in peri-implant bone stress. Specifically, cortical bone stress in D4 bone increased from approximately 79 MPa to 142 MPa with higher IT, exceeding physiological limits and elevating the risk of microfractures and bone necrosis. In contrast, lower IT values kept stress within safe limits, ensuring optimal primary stability without damaging the bone. These results underscore the need to strike a balance between achieving sufficient implant stability and avoiding mechanical trauma to the surrounding bone. Conclusions: Accurate control of insertion torque during the placement of ultra-short dental implants is crucial to minimize bone damage and promote optimal osseointegration. Excessive torque, especially in low-density bone, can compromise implant success by inducing excessive stress, thereby increasing the risk of early failure. Full article

Background: The digital transformation in dentistry is increasingly reshaping treatment procedures, offering new opportunities and advancements. While digitalization promises enhanced efficiency and quality of care through the standardization, acceleration, and simplification of workflows, it also introduces challenges related to mental health. Studies investigating digitization-associated stressors and resources, as well as health- and work-related outcomes, in the dental sector are still rare. In the context of ongoing digitalization, further studies are needed to examine the need for and the current status of the implementation of measures preventing techno-stress and stress-related outcomes. This study explores the use of digital tools in dental practices and their relationship to the techno-stress among German dentists. It identifies key stressors and resources associated with digital technologies, aiming to inform preventive measures, as well as training and support strategies to mitigate digital stress. Methods: A qualitative study was employed, involving ten problem-centered, guideline-based expert interviews with German dentists. The interviews were analyzed using MAXQDA software, following the focused interview analysis framework by Kuckartz and Rädiker. Coding and thematic analysis adhered to the Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist and qualitative research quality criteria by Mayring. Results: This study identified a dual impact of digitalization in dentistry. On the one hand, digital tools significantly enhance workflow efficiency, diagnostic accuracy, and patient outcomes. On the other hand, they pose challenges like technostress, high financial costs, and the need for continuous learning. Findings reveal that the perceived usefulness of digital technologies is closely linked to the level of techno-stress experienced, while the amount, intuitiveness, and ease of use significantly influence stress levels. Conclusions: Digital transformation offers substantial benefits for dental practices but requires a balanced approach to implementation. Participants highlighted the need for proactive measures, such as targeted training, technical support, and stress-reducing interventions to reduce techno-stress levels. The digital transformation must be supported by coordinated efforts across academia, industry, and policy to strengthen digital competencies—creating a healthier, more resilient digital work environment. Future research should focus on the causal relationship between techno-stress and adverse long-term consequences, such as burnout or mental disorders, among dentists. Full article

It is widely recognized that excessive stress and/or strain can lead to peri-implant bone atrophy; therefore, the clinical success of dental implants is intrinsically related to their biomechanical behavior. This study evaluates the influence of the diameter, length, and material [Ti6Al4V (α+β Ti) and Ti35Nb7Zr5Ta (β-Ti)] of a novel cylindrical dental implant on stress and strain levels within maxillary bone of type II quality. The implant design aims to ensure an appropriate distribution of stresses and strains within the peri-implant bone structures (cortical and trabecular bones) while also facilitating surgical machining by requiring a simple, linear, and less expensive bone incision. This approach minimizes the risk of thermal necrosis, a common complication in osteotomies for conical implants that can lead to peri-implant bone loss. Using finite element analysis, stress and strain patterns were evaluated in the maxillary second premolar region under static delayed loading. The results reveal that the cortical bone strains remained below the critical threshold (0.003) to prevent resorption. In the trabecular bone, only larger diameter/length configurations satisfied the previous strain criterion. In all simulations, trabecular bone stress remained below 3 MPa, whereas cortical bone stress peaked at 78 MPa. Notably, the implant model with the largest diameter/length minimized stress and strain concentrations in type II bone when compared to smaller designs, thereby demonstrating its biomechanical advantage. Full article