Search Results (5,092)

Objective: This study aimed to evaluate the mean age of eruption of permanent teeth and their clinical emergence sequence in a longitudinal sample of children from a multi-ethnic urban population. Methods: A total of 854 children (413 females and 441 males), aged between 4 and 13 years, were examined annually for a minimum of 4 consecutive years, as part of their annual dental screening appointment. The presence of permanent teeth was recorded at each examination. Mean and median ages, with standard deviations, of individual tooth eruption were calculated, in addition to the eruption sequence, and the analysis of the data was performed using the lognormal distribution model. Regarding the error of the method, two examiners reviewed all relevant dental screening forms, and any discrepancies were resolved through consultation with the senior author. Results: The sequence of permanent tooth eruption followed a consistent pattern across sexes, with distinct differences between the maxillary and mandibular arches. In the maxilla, eruption began with the first molar, while in the mandible, it started with the central incisor. Mandibular teeth generally erupted earlier than maxillary teeth, with girls experiencing earlier eruption than boys, with some exceptions, and prolonged eruption periods. No statistically significant differences were found in the timing of eruption between contralateral homologous teeth. Conclusions: Based on the present data, the observed sequence of tooth eruption in a multi-ethnic urban population showed similar patterns across sexes. Mandibular teeth generally erupt earlier than maxillary teeth, with girls experiencing earlier eruption than boys. Full article

Objective: To analyze the composition of the oral microbiome in periodontal pocket lesions and on the tongue dorsum of patients with Helicobacter pylori-associated gastric disease. Materials and Methods: Patients diagnosed with gastric disease and H. pylori (HP+) were evaluated in comparison to a control group of H. pylori-negative patients without gastric disease (HP−). Periodontal and oral health clinical parameters (PPD, BoP, PSE, plaque score and modified DMFT) were assessed for each patient. Microbiological samples were collected from the deepest periodontal pockets and tongue dorsum, followed by DNA extraction, 16S rRNA PCR amplification, and Next-Generation-Sequencing (NGS) analyses. Results: Sixty-seven patients (27F; 40M, aged 35–85 years) were enrolled. Of these, 52 were HP+ and 15 were HP−. HP+ patients exhibited a significantly higher presence of decayed teeth (p < 0.05) and slightly fewer missing teeth (p > 0.05). The plaque score was significantly higher in HP+ patients (p < 0.05), while PPD and BoP showed no significant differences (p > 0.05). NGS analysis revealed no presence of H. pylori in any samples of both periodontal and tongue sites. HP+ patients showed a distinct microbial composition, including higher prevalence of Capnocytophaga, Fusobacterium, and Peptostreptococcus genera in both locations (pockets and tongue dorsum). Conclusions: The study demonstrated that HP+ patients exhibit distinct oral microbial profiles compared to HP− patients, especially in areas with deeper periodontal pockets. H. pylori was not detected in the oral microbiomes of either group. Full article

Biofilms are a spontaneously formed slimy matrix of extracellular polymeric substances (EPS) enveloping miniature bacterial colonies, which aid in pathogen colonization, shielding the bacteria from antibiotics, as well as imparting them resistance towards the same. Biofilms employ a robust communication mechanism called quorum sensing that serves to keep their population density constant. What is most significant about biofilms is that they contribute to the development of bacterial virulence by providing protection to pathogenic species, allowing them to colonize the host, and also inhibiting the activities of antimicrobials on them. They grow on animate surfaces (such as on teeth and intestinal mucosa, etc.) and inanimate objects (like catheters, contact lenses, pacemakers, endotracheal devices, intrauterine devices, and stents, etc.) alike. It has been reported that as much as 80% of human infections involve biofilms. Serious implications of biofilms include the necessity of greater concentrations of antibiotics to treat common human infections, even contributing to antimicrobial resistance (AMR), since bacteria embedded within biofilms are protected from the action of potential antibiotics. This review explores various contemporary strategies for controlling biofilms, focusing on their modes of action, mechanisms of drug resistance, and innovative approaches to find a solution in this regard. This review interestingly targets the extracellular polymeric matrix as a highly effective strategy to counteract the potential harm of biofilms since it plays a critical role in biofilm formation and significantly contributes to antimicrobial resistance. Full article

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

Objective: Due to the increasing esthetic demand among pediatric patients and different restorative materials, we focused on analyzing which of the options of restorations may provide superior clinical outcomes. Methods: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) using PubMed and Cochrane databases. Results: Five articles met all inclusion criteria from an initial pool of 359 articles identified in the initial search. Greater bond strength was observed when pulpotomized teeth were restored with Biodentine^® and resin composites compared to resin-modified glass ionomer cements (RMGICs). When comparing pulpotomies in primary teeth with MTA and Biodentine^®, the fracture resistance values were higher in the pulpotomized teeth with Biodentine^® than with MTA. Additionally, following a narrative synthesis in MTA-treated teeth, a higher risk of failure was observed using RMGICs or composite instead of stainless-steel crowns (SCCs) as the final restorative material. Conclusions: Variables such as the type of final restoration can affect the survival of primary teeth after pulpotomy reconstruction. Regardless of the pulp material, survival with SSCs is higher, but resin composites appear to be a viable restorative material after Biodentine^® application. Full article

Background: Dentinal hypersensitivity (DH) significantly impacts oral health-related quality of life. While global prevalence estimates range from 10–15%, region-specific data from Saudi Arabia remain limited. This study also aligns with Saudi Vision 2030’s mental health initiatives, as DH-associated anxiety impacts overall well-being. This study assessed DH prevalence and quality of life impact among Saudi adults. Methods: A cross-sectional online survey was conducted among 748 Saudi adults aged ≥ 18 years between April and May. Data were collected using a validated Arabic Dentinal Hypersensitivity Experience Questionnaire (DHEQ) alongside socio-demographic variables. Participants reporting DH symptoms within 12 months were included in impact analyses. Descriptive statistics and one-way ANOVA examined associations between DHEQ scores and participant characteristics. Results: Self-reported DH prevalence was 54.3% (n = 406), substantially exceeding global estimates. Among affected individuals, mean DHEQ score was 0.56 ± 0.19, indicating moderate-to-substantial quality-of-life impact. Functional limitations were most affected, particularly enjoyment of eating and drinking (0.72 ± 0.21). Significant associations were identified between higher DHEQ scores and age extremes (<18 and >35 years; p < 0.001), higher income levels (p = 0.032), fewer teeth (p = 0.040), and dental pain presence (p = 0.009). Sex, residence, education, and employment showed no significant associations. Conclusions: More than half of Saudi adults reported DH symptoms, representing a significant public health concern with substantial quality of life implications. Prevalence substantially exceeds global estimates, highlighting the need for targeted interventions. Age, income, tooth count, and pain presence emerged as key factors. These findings support developing population-specific prevention strategies, particularly targeting younger and older adults with tooth loss. Full article

This article analyzes statistics on the failure of technological equipment, assemblies, and mechanisms of agricultural (and other) machines associated with the breakdown or failure of gear pumps. It was found that the leading causes of gear pump failures are the opening of gear teeth contact during pump operation, poor assembly, wear of bushings, thrust washers, and gear teeth. It has also been found that there is a problem related to the restoration, repair, and manufacture of parts in the conditions of enterprises serving the agro-industrial complex of the Republic of Kazakhstan (AIC RK). This is due to the lack of necessary technological equipment, tools, and instruments, as well as centralized repair and restoration bases equipped with the required equipment. This work proposes to solve this problem by applying AM technologies to the repair and manufacture of parts for agricultural machinery and equipment. The study results on the stress–strain state of support bushings under various pressures are presented, showing that a fully filled bushing has the lowest stresses and strains. It was also found that bushings with 50% filling and fully filled bushings have similar stress and strain values under the same pressure. The difference between them is insignificant, especially when compared to bushings with lower filling. This means that filling the bushing by more than 50% does not provide a significant additional reduction in stresses. In terms of material and printing time savings, 50% filling may also be the optimal option. Full article

Background/Objectives: Anterior dental trauma in adolescents presents complex restorative challenges due to ongoing craniofacial development and high aesthetic expectations. This study evaluated the long-term clinical performance of feldspathic ceramic veneers and lithium disilicate crowns used in the anterior region following dental trauma in adolescents. Methods: A total of 209 restorations were placed in 85 adolescents (50 females, 35 males), aged 11.1–17.9 years (mean age: 15.1 years). Of these, 144 were lithium disilicate crowns, and 65 were feldspathic ceramic veneers. All restorations were fabricated using minimally invasive protocols and followed up for periods ranging from 3 to 60 months. Outcomes were assessed based on standardized clinical criteria for success and failure. Results: Lithium disilicate crowns exhibited superior long-term performance, with the majority of failures occurring in feldspathic veneers (p < 0.001), primarily due to chipping or structural fracture. Age and gender had no statistically significant influence on failure rates. Conclusions: Both feldspathic and lithium disilicate ceramic restorations represent viable treatment options for anterior dental trauma in adolescents. However, lithium disilicate demonstrates greater mechanical reliability, particularly in teeth with significant hard tissue loss. These results support the use of durable ceramic materials in adolescent restorative protocols involving dental trauma. Full article

The aim of this study was to compare the forces and moments exerted by thermoformed aligners (TFMs) and direct printed aligners (DPAs) on the maxillary left central incisor (21) and adjacent teeth (11, 22) during lingual bodily movement of tooth 21. Methods: An in vitro setup was used to quantify forces and moments on three incisors, which were segmented and fixed onto multi-axis force/moment transducers. TFM were fabricated using 0.76 mm-thick single-layer PET-G foils (ATMOS; American Orthodontics, Sheboygan, WI, USA) and multi-layer TPU foils (Zendura FLX; Bay Materials LLC, Fremont, CA, USA). DPAs were fabricated using TC-85 photopolymer resin (Graphy Inc., Seoul, Republic of Korea). Tooth 21 was planned for bodily displacement by 0.25 mm and 0.50 mm, and six force and moment components were measured on it and the adjacent teeth. Results: TC-85 generated lower forces and moments with fewer unintended forces and moments on the three teeth. TC-85 exerted 0.99 N and 1.53 N of mean lingual force on tooth 21 for 0.25 mm and 0.50 mm activations, respectively; ATMOS produced 3.82 N and 7.70 N, and Zendura FLX produced 3.00 N and 8.23 N of mean lingual force for the same activations, respectively. Bodily movement could not be achieved. Conclusions: The force systems generated by clear aligners are complex and unpredictable. DPA using TC-85 produced lower, more physiological force levels with fewer side effects, which may increase the predictability of tooth movement and enhance treatment outcome. The force levels generated by TFM were considered excessive and not physiologically compatible. Full article

In this research project a large linear electromagnetic actuator (LLEA) was designed and manufactured. The electromagnetic performance was published in previous works, but in this paper we focus on the technological challenges related to the manufacturing in particular. This LLEA was based on the magnet-free switched-reluctance principle, having six effective energised stator “teeth” and four passive mover parts (4:6 ratio). Various aspects and challenges encountered during the manufacturing, transport, and assembly are discussed. Thermal expansion of steel contributed to the decision of the modular design, with each module having 1.3 m in length, with a 2 mm longitudinal dilatation gap. The initial prototype was tested with a 10.6 m length, with plans to extend the test track to 60 m, which was fully achievable due to the modular design and required 29 tons of electrical steel to be built. The stator laminations were cut by a bespoke progressive tool with stamping, and other parts by a CO₂ laser. Mounting was based on welding (back of the stator) and clamping plates (through insulated bolts). The linear longitudinal force was on the order of 8 kN, with the main air gap of 7.5–10 mm on either side of the mover. The lateral forces could exceed 40 kN and were supported by appropriate construction steel members bolted to the concrete floor. The overall mechanical tolerances after installation remained below 0.5 mm. The technology used for constructing this prototype demonstrated the cost-effective way for a semi-industrial manufacturing scale. Full article

Background/Objectives: The present study aimed to evaluate the oral health and patient satisfaction of flexible and non-metal clasp dentures (NMCD) compared to removable partial dentures (RPD) using a systematic review. Methods: The PICOS framework of this review was as follows: Do rehabilitations involving flexible dentures or NMCD have a similar success rate to those using RPD? Thus, the PICOS approach involves the following topics: (P) Population/Problem: partial edentulous adult patients; (I) Intervention: patients rehabilitated with flexible dentures or NMCD; (C) Comparison: patients rehabilitated with standard RPD; (O) Outcome: clinical parameters such as oral health, masticatory function, and patient satisfaction; and (S) Study Type: clinical trials and observational studies (cohort, case–control, and cross-sectional). No language restrictions were applied to the studies. The search strategy consisted of the following keywords in different databases: ((flexible) OR (nonmetal) OR (non-metal) OR (thermoplastic)) AND (denture). Only clinical trials and observational studies (cohort, case–control, and cross-sectional studies) from the last 15 years were included, and no language restrictions were applied. Studies that did not describe the denture material were excluded. Results: Of the 2197 potentially relevant records, 14 studies were included in the present review. Two studies reported retrospective results, while twelve reported a prospective evaluation. Considering the thermoplastic materials, five studies evaluated polyester, five polyamides, three polyacetals, and only one study evaluated polyetheretherketone (PEEK). Flexible dentures and NMCD demonstrated similar periodontal status and bone levels on abutment teeth to RPD after up to 12 months. Flexible dentures exhibited a higher degree of redness of the mucosa after 12 months. One study showed a lower maximum bite force for flexible dentures compared to RPD. No study has performed a clinical evaluation of mastication and chewing ability. Conclusions: Despite increased short-term patient satisfaction for flexible dentures and NMCD, there is weak evidence to support a similar clinical performance of flexible dentures and NMCD to RPD. Full article

For paleoenvironmental reconstruction, paleontologists prefer large, well-preserved fossils. Yet, such specimens are rare, and countless small fragments, though abundant, often go unused. These fragments lack visible internal structure, thus requiring etching, a procedure not permitted on large, intact specimens. Our research introduces a three-step method to identify the nature of these small fragments. With their structures revealed, we can then analyze the chemical composition of identified tissues. The method was tested using samples of vertebrate fossils collected in Malawi. Even with a limited number of samples, multivariate analyses (Principal Component Analyses—PCA) of these chemical data effectively differentiate fossil and recent samples, as well as bone, dentin, and enamel. This approach successfully reveals the behavior of the mineralized tissues of fossil samples. Ultimately, by leveraging microstructural and chemical data, we can study previously unidentified fragments or rare fossils. This allows for the estimation of preservation state and helps to avoid biases in paleoenvironmental reconstructions. Full article

Background/Objectives: The aim of this study was to evaluate the level of awareness among dental students and practitioners regarding the utilization of endocrowns in clinical settings, along with any differences in knowledge based on gender, educational level, and workplace. Methods: A cross-sectional online survey-based study was conducted, including 1154 participants from various dental institutions across Saudi Arabia. The questionnaire included demographic data and closed-ended questions focused on knowledge and awareness of endocrowns. Data was analyzed using statistical tests, including chi-square, to see any significant differences. Results: Most participants (81%) had knowledge about endocrowns, mainly from their colleagues. Knowledge levels and preferences (like the use of lithium disilicate and adhesive resin cement) differed based on gender, educational level, and workplace. Male participants and undergraduates showed better awareness in some areas. Faculty members mostly depend on college training, while private practitioners obtain most of their information from workshops. Conclusions: Males showed significant superiority in knowledge about endocrown usage. Colleges were the most prevalent source of information regarding endocrown restorations. Significant molar tooth loss and restricted inter-arch space were the most common reasons for utilizing endocrowns. Moreover, endocrowns were considered a viable alternative to traditional post and core. Full article

Bycatch is the most common cause of death of small delphinids worldwide, including the Mediterranean Sea. The diagnosis of bycatch as cause of death in stranded cetaceans depends on the cumulative presence of multiple findings, termed bycatch criteria. In this study, we retrospectively evaluated the presence of bycatch criteria in 138 necropsied cetaceans, 136 stranded and 2 confirmed bycaught, in the Catalan Mediterranean Sea across a 13-year period. With the aim of identifying the most specific and reliable bycatch criteria, the animals’ cause of death was classified as either bycaught or other causes. Animals were necropsied according to standard procedures with complete histopathological examination and ancillary diagnostic techniques. We reviewed the necropsy reports and photographs of 138 cetaceans of seven species. Bycatch had been determined as the cause of death/stranding in 40 (29%) necropsied cetaceans. Both sexes were equally represented in the bycatch group. Bycatch was diagnosed in the Mediterranean common bottlenose dolphin (10/14; 71.4%), striped dolphin (29/108; 26.9%), and Risso’s dolphin (1/11; 9.1%). Sixty-seven out of 98 (68.3%) cetaceans that had been classified as non-bycatch had one or two bycatch criteria. Cetaceans with two and three major criteria had an overlap of causes of death, as some animals were diagnosed with bycatch and others with other causes of mortality. Animals with four criteria were invariably diagnosed as being bycaught. Recent feeding, absence of disease, good nutritional status, marks of fishing gear, multiorgan intravascular gas bubbles, hyphema and amputations or sharp incisions presumably inflicted by humans were significantly more likely to result in a diagnosis of bycatch, while loss of teeth and cranial fractures were not. None of the dolphins diagnosed as bycatch had ingested fishing gear. Our results highlight the relevance of bycatch as the cause of death of dolphins in the Mediterranean and suggest that some criteria traditionally linked to bycatch are not specific for bycatch in our region. Full article

Background: Stable post-surgical wound healing surrounding teeth and dental implants is essential for achieving excellent clinical outcomes, both during the initial phases of treatment and over the long term. Objectives: This work follows the new emerging trend of case-based literature reviews. The aim of this review includes providing clinical findings from case series that demonstrate the efficacy of using blue^®m oxygen treatment to promote post-surgical wound healing in patients that underwent periodontal and dental implant surgeries. In addition, a systematic review of the literature aimed to answer the focused research question: “In periodontal and implant surgeries, what are the aftercare protocols used to maintain optimal wound healing?” Case Presentation: One clinical case report involved the presentation of complex periodontal surgery. The other two cases focused on advanced implant surgeries. All patients were treated post-surgically with the local application of an oxygen-based therapy (blue^®m) gel. This therapy was further emphasized during the wound-healing phase by instructing patients to maintain thorough dental hygiene using toothpaste and mouthwash containing a similar oxygen-release formulation (blue^®m). Patients achieved satisfactory treatment outcomes. Systematic Review: PubMed and EMBASE were used in order to search for relevant studies in the scientific literature published up until June 2025. Only human clinical studies that used a specific protocol in regard to aftercare wound healing after periodontal or dental implant surgeries were included. As a result, 27 clinical studies were included. The outcome data were categorized and summarized. Conclusions: The use of local oxygen-based therapy showed a positive effect as a conventionally used aftercare modality in maintaining optimal post-surgical wound healing, following periodontal and implant surgeries. Further clinical studies are needed. Full article