Search Results (124)

Background/Objectives: Traumatic dental injuries involving the maxillary anterior teeth are common; however, combined extrusive and lateral dislocation during active orthodontic treatment is uncommon and presents unique management challenges. This case report describes the multidisciplinary management of traumatic extrusive and lateral dislocation of the maxillary right lateral incisor (#7) and maxillary right central incisor (#8) in a 27-year-old patient undergoing fixed orthodontic treatment following sports-related trauma. Methods: Clinical examination revealed marked coronal and lateral displacement, pathologic mobility, gingival laceration, active bleeding, and deformation of the orthodontic archwire. Both affected teeth had complete root formation. Emergency management included immediate repositioning of the displaced teeth and urgent endodontic treatment. Semi-rigid stabilization was achieved using metallic ligatures and a rectangular stainless-steel orthodontic archwire, supplemented by temporary skeletal anchorage with a mini-screw and posterior bite turbos to reduce occlusal loading. The patient was monitored clinically and radiographically throughout healing and subsequent orthodontic treatment. Results: Follow-up examinations demonstrated favorable periodontal healing, stable retention of the traumatized teeth, absence of pathologic mobility, and successful continuation of orthodontic treatment. Radiographic evaluation showed no evidence of inflammatory root resorption or other significant complications. At the 16-month follow-up, the affected teeth remained functional and stable, and implant placement was successfully completed at the congenitally missing maxillary canine site. Conclusions: This case highlights the importance of immediate interdisciplinary management of traumatic dental dislocation during orthodontic treatment. Fixed orthodontic appliances, when appropriately incorporated into emergency stabilization protocols, may contribute to successful tooth retention and favorable long-term outcomes. Full article

Modern prosthetic dentistry has been significantly reshaped by adhesive dentistry, CAD/CAM technologies, and advanced ceramic materials, leading to the development of minimally invasive all-ceramic restorative approaches. However, the longevity of the adhesive interface is fundamental to the long-term effectiveness of these restorations. With a focus on bond durability and clinical performance, this narrative review aims to evaluate modern adhesive strategies, tooth preparation requirements, and cementation techniques in all-ceramic minimally invasive restorations. Methods: A narrative review of the literature was performed using Google Scholar, Web of Science, and PubMed/MEDLINE databases. Publications from 2000 to 2026 were analysed. In vitro research, narrative reviews, and systematic reviews related to adhesive systems, resin cements, CAD/CAM materials, and minimally invasive prosthodontic principles were the core subjects of the research. Results: The findings indicate that material selection, surface conditioning techniques, and cementation methods have a significant impact on the clinical effectiveness of all-ceramic restorations. Retention and marginal sealing are greatly enhanced by resin-based adhesive systems. Nevertheless, hydrolytic degradation, procedure sensitivity, and substrate-related factors remain a challenge to the adhesive interface. Advances in CAD/CAM and ultra-conservative designs, like occlusal veneers and partial-coverage restorations, have increased treatment alternatives while ensuring acceptable functional and aesthetic results. Conclusions: Minimally invasive all-ceramic restorations represent a conservative and clinically effective treatment approach in modern prosthodontics. Their long-term performance is primarily dependent on adhesive interface stability and adherence to evidence-based clinical protocols. Continued developments in adhesive materials and ceramic systems are expected to improve bond durability and broaden clinical indications. Full article

Efficient seedbed preparation under conservation-oriented tillage requires balanced aggregate fragmentation, surface microrelief and energy demand. This study investigated the influence of passive toothed roller parameters on soil fragmentation, surface roughness, draft force and fuel consumption during chisel tillage under medium-loam Calcisol conditions. Three configurations were compared: a chisel plow without a roller, with a slat roller and with a toothed roller. An analytical framework describing aggregate capture, tooth–soil contact frequency and resistance formation was combined with field experiments and regression-based response surface analysis. The toothed roller improved measured soil treatment indicators compared with the no-roller and slat-roller configurations due to discrete tooth–soil interaction, localized stress concentration and repeated loading of loosened aggregates. Rational parameter ranges were identified: a roller diameter of 0.45–0.46 m, 13–15 teeth, transverse spacing of 8.0–8.6 cm, a tooth height of 7.5–8.5 cm and specific load of 0.9–1.1 kN m⁻¹. Under the selected configuration, aggregates smaller than 50 mm increased from 76.1% to 88.0%, surface roughness decreased from 6.8 to 3.7 cm and residue retention remained above 60%. Fuel consumption increased to 28.4–28.5 L ha⁻¹, reflecting the additional energetic cost of fragmentation and levelling. The approach supports rational selection of passive toothed roller parameters under the tested conditions. Full article

Most existing dental restorative materials exhibit limited bioactivity, insufficient acid resistance, and poor mechanical compatibility with natural tooth structures. This study involved an in vitro approach in which a biomimetic fluoride-modified functionally gradient dental restorative material was prepared from sol–gel-derived mesoporous silica through mineralization induced via SBF solution. They synthesized bioactive restorative materials by introducing silica into a simulated body fluid (SBF) for biomimetic mineralization and generating hydroxyapatite on the silica surface. XRD, FTIR, SEM, and EDS analyses confirmed the presence of hydroxyapatite and fluorapatite-like phases. The results showed statistically significant improvements (p < 0.05) in the mechanical properties. The surface hardness of the developed restorative system ranged from 214 HV for the prepared silica to 392 HV for the fluoride-modified specimens. Biomimetic mineralization and fluoride modification increased the shear bond strength to dentin substrates from 9.2 MPa to 21.4 MPa and the wear from 12.8 mg to 3.6 mg, respectively. Acid resistance evaluation also showed that the specimens with fluoride modification had the highest value of hardness retention (92.1%) after acid resistance due to the formation of chemically stable and dense apatite-rich layers on the surface. The functionally graded structure demonstrated a partial biomimetic resemblance to certain hierarchical and functional characteristics of natural dental tissues under in vitro conditions. In vitro studies on bioactivity, mechanical properties, and resistance to acidic environments of the synthesized restorative showed promising results for future dental restoration applications. Full article

Background/Objectives: Fixed orthodontic appliances interfere with oral hygiene and contribute to plaque retention, gingival inflammation and demineralization of enamel. Standard techniques for keeping oral hygiene (tooth brushing, mouthwashes, dental floss, interdental brush, etc.) are not sufficiently effective. The aim of this study was to investigate the effectiveness, safety, tolerability, and influence on quality of life of an electrolysis device being added to standard techniques of oral hygiene in orthodontic patients, compared to standard methods only. Methods: This 6-month study was designed as an observational prospective-cohort investigation. Primary outcomes of the study were indices of gingival inflammation and bleeding, dental plaque indices, the number of white spots on enamel, and safety (incidence of adverse events). Secondary outcomes were quality of life and overall costs of keeping oral hygiene. Results: The addition of the Neo Pill device to standard oral hygiene maintenance measures was associated with improvements in oral health indices after 6 months; however, given the non-randomized, preference-driven design, these findings reflect an association and should not be interpreted as evidence of causal efficacy. After 6 months, the primary outcomes of the study were significantly reduced compared to the application of only standard oral hygiene methods (from 21 to 55% reduction); the quality of life related to oral health was higher (for 14%), the tolerability of maintaining oral hygiene was the same as with standard measures and the costs of maintaining oral hygiene consumables were lower in the Neo Pill group (median difference 30%); however, this figure excludes the acquisition cost of the device itself, which was donated to all participants by the manufacturer, and the 95% confidence interval for this difference includes zero. Conclusions: The addition of an electrolysis device to standard oral hygiene maintenance measures in people wearing fixed orthodontic appliances was associated with improvements in gingival inflammation, papillary bleeding, and dental plaque indices—outcomes measured with established clinical instruments. Apparent reductions in white-spot lesion counts were also observed but should be considered exploratory given the absence of calibrated or blinded lesion assessment. These findings are preliminary and do not establish causal efficacy. Full article

Three-dimensional (3D)-printed dentures are often fabricated from a single tooth-colored resin and externally characterized using stains and glaze coatings to enhance gingival esthetics and surface properties. However, routine toothbrushing may degrade these coatings, potentially affecting surface gloss and roughness. This study evaluated the effects of stain timing and glaze application on the gloss and surface roughness of a 3D-printed denture resin following simulated toothbrushing. Eighty disc-shaped specimens (12 mm × 3 mm) were fabricated and assigned to two staining systems (OPTIGLAZE Color and Palette 2.0), with subgroups based on stain timing (before or after post-curing) and glaze application (with or without glaze) (n = 10). Specimens underwent 20,000 cycles of simulated toothbrushing, and gloss and surface roughness were measured before and after brushing. Data were analyzed using two-way ANOVA (α = 0.05). Glaze application significantly improved gloss retention for both staining systems (p < 0.001), while stain timing had no independent effect. Glaze application with Palette 2.0 demonstrated improved gloss retention when post-cured in a post-curing unit. Toothbrushing increased surface roughness in all groups, with no significant effects of stain timing or glaze. Within the limitations of this study, glaze improves gloss stability, whereas stain timing has minimal influence and does not affect surface roughness. Full article

Background/Objectives: Multiple impacted teeth are defined as the sequential impaction of more than two teeth in the alveolar bone, whether unilateral or multilateral. Multiple impactions are an uncommon and rare phenomenon demanding thorough treatment planning and careful execution, but data on the prevalence of multiple impactions is scarce in the literature. In cases of multiple impactions, clinicians generally perform a 3D assessment using CBCT to determine tooth positions, establish a sequence of surgical exposures, implement suitable traction, and utilise appropriate biomechanics. A multidisciplinary approach between orthodontists and oral surgeons is essential to achieve optimal results. Methods: This case report presents non-syndromic multiple impactions of three upper left permanent anterior teeth—21, 22, and 23—along with a retained supernumerary tooth preventing their eruption and a fused primary tooth. The primary teeth and the impacted supernumerary tooth were surgically removed. A digitally designed transpalatal arch was used to preserve the space and to act as anchorage for the orthodontic traction. After an 8-month observational period without spontaneous eruption, surgical exposure was carried out using the closed exposure technique. Subsequently, elastic traction was performed, guiding the impacted teeth into the dental arch. Results: The multiple impacted teeth were successfully aligned in the dental arch, achieving symmetry in the frontal segment while preserving periodontal health. In order to ensure stability during the retention period, thermoformed retainers were used. Conclusions: Each complex and rare clinical case poses a challenge to orthodontists and is important for the scientific literature as it provides valuable clinical experience. Full article

Background: A solid understanding of dental and craniofacial anatomy is essential for reliable clinical practice, yet long-term retention of anatomical knowledge is known to decline as students progress through their training. Although digital- and image-based resources are widely used in anatomy education, it remains unclear whether two-dimensional (2D) representations support durable recognition of complex anatomical structures. This study investigated whether tactile engagement with real three-dimensional (3D) anatomical specimens enhances long-term identification accuracy compared with standardized 2D images. Materials and Methods: Eighty-nine fifth-year dental students at the University of Oslo were assessed approximately 2.5 years after completing their formal anatomy course. All students completed two sequential identification tests on the same day: a 2D image-based test followed immediately by an equivalent test using real extracted human teeth and real skull bones. The assessments comprised 28 osteology structures and 14 teeth. Performance between conditions was compared using mixed-effects logistic regression with test modality as a fixed effect and participant and anatomical item as crossed random effects. Results: Overall identification accuracy increased from 52% in the 2D condition to 74% in the 3D tactile condition (p < 0.0001). Mean accuracy for osteology improved from 0.519 (SD = 0.074) to 0.708 (SD = 0.072) (p < 0.0001), while tooth morphology scores increased from 0.535 (SD = 0.097) to 0.795 (SD = 0.110) (p < 0.0001). All individual teeth and nearly all osteological structures showed significantly higher identification accuracy in the 3D condition. The largest gains were observed for structures with low 2D recognition. Conclusions: Tactile interaction with real 3D anatomical specimens substantially enhances long-term recognition of dental and craniofacial anatomy. These findings support the continued integration of hands-on, three-dimensional learning alongside digital resources in dental anatomy education to promote durable anatomical understanding and clinical preparedness. Full article

African swine fever (ASF), caused by African swine fever virus (ASFV), is a highly destructive transboundary disease in domestic pigs. The circulating virus in this study belonged to ASFV genotype II, commonly associated with high virulence. In endemic regions such as Thailand, limited vaccine availability and shortages of naïve breeding stock necessitate reliance on early detection, surveillance, and the retention of convalescent sows, thereby raising concerns regarding viral persistence and reproductive performance. This study evaluated the long-term reproductive performance of convalescent sows compared with naïve cohorts under co-habitation conditions, while assessing the efficacy of passive surveillance and strict biosecurity in preventing viral transmission from both internal and external sources. Convalescent sows showed reproductive performance comparable to naïve cohorts across two parities. Long-term co-habitation with naïve sentinel pigs was not associated with detectable viral transmission, although low-level viral persistence or intermittent shedding cannot be excluded. From a disease control perspective, the transition from delayed detection to enhanced passive surveillance facilitated early clinical recognition and targeted removal (“tooth extraction”) of infected animals, effectively limiting intra-herd transmission without full depopulation. Importantly, irrespective of the uncertain carrier status, strict biosecurity and rapid response protocols appeared effective in mitigating both external introduction and within-farm transmission of ASFV. These findings suggest that, under appropriate management and biosecurity conditions, convalescent sows may be reintegrated into production systems with caution. Full article

To address the problems of high unharvested rates and header loss rates in existing plot-breeding wheat harvesters, this study presents the design of a comb-type header for plot wheat harvesters. Based on the loss suppression mechanism during wheat harvesting, the key components of the comb-type header were designed. To address the issue in which some wheat ears escape combing during the harvesting process, a multi-stage comb-tooth structure was developed. For the problem of seed retention on the bottom plate of the screw conveyor, the telescopic tooth at the feeding port of the screw conveyor was replaced with a scraper, and a rubber plate was added. To determine the optimal combing time, wheat plant posture changes under the action of the nose (hereinafter referred to as the nose) were analyzed through theoretical analysis, simulation, and bench testing. It was determined that the optimal combing moment occurs when the plants begin to rebound to the maximum reverse bending. On this basis, a numerical simulation model of the header combing system was constructed using the discrete element method, with the header loss rate as the evaluation index to explore the influence of the nose height, the machine forward speed, and the combing drum rotation speed on the header performance. A regression model of header loss was constructed using the Box–Behnken response surface method, and the optimal working parameters were determined as follows: a nose height of 554 mm, a machine forward speed of 0.65 m/s, a combing drum rotation speed of 667 r/min, and the predicted loss rate of 8.59%. To verify the operational performance of the comb-type header, a field test of the wheat-harvesting prototype was conducted. The results showed that, under the optimal working parameters, the header loss rate was 7.24%, no wheat ears escaped combing, and no seed retention occurred in the header, which meets the requirements for plot wheat-breeding harvesting. This study provides a theoretical basis for the design and development of small-sized combing harvesters. Full article

Background/Objectives: Oral function impairment negatively impacts nutrition, health, and quality of life in older adults. While retaining ≥20 natural teeth is often recommended for maintaining oral function, its validity is uncertain, particularly for those who adapt to tooth loss with dentures. This study aimed to determine the minimum number of remaining functional teeth necessary to prevent oral hypofunction in older adults, focusing on two diagnostic criteria: decreased masticatory function and reduced occlusal force. Methods: A total of 154 participants (≥60 years) were included. Oral examination assessed the number of remaining functional teeth. To assess masticatory function, masticatory performance was objectively measured using a visual scoring method of gummy jelly, and occlusal force was quantified with pressure-sensitive film. Pearson’s correlation analyzed relationships among variables, while receiver operating characteristic (ROC) analysis identified optimal tooth number cut-offs for detecting decreased masticatory function (score ≤ 2) and reduced occlusal force (<500 N). Results: Significant positive correlations were found between the number of remaining functional teeth and both masticatory performance (r = 0.591, p < 0.001) and occlusal force (r = 0.453, p < 0.001). ROC indicated that 17 teeth was the optimal threshold for identifying both decreased masticatory performance and reduced occlusal force, with sensitivities of 0.79 and 0.72 and specificities of 0.93 and 0.88, respectively. Conclusions: Retention of 17 or more remaining functional teeth may be sufficient to maintain adequate masticatory performance and occlusal force. These findings serves as a preliminary guide for treatment planning and targeted interventions focused on preserving tooth retention and improving oral function in aging populations. Full article

Background: Vertical root fracture (VRF) is a severe complication of endodontically treated teeth with a poor prognosis. Despite many tentative tooth-preserving approaches, the current main treatment remains tooth extraction or root resection, which is largely due to the difficulty in balancing the mechanical strength for fracture fixation and biological properties for periodontal healing. Moreover, all documented reports regarding VRF repairing so far were limited to anterior teeth and premolars. Thus, the objective of this case report was to present a novel surgical treatment approach for repairing VRF of molars. Methods: Three patients (2 females, 1 male; aged 30–33 years) with endodontically treated molars (Tooth #46, #16, #37) diagnosed with VRF were treated with a dual-layered repair approach with modified fracture lines and retention forms through intentional replantation. Results: After 18, 21, and 36 months of follow-up, respectively, all three cases showed no clinical symptoms, normal tooth mobility and periodontal probing, as well as reduced periradicular radiolucency on radiographs. Root resorption or ankylosis was not observed. Conclusions: The novel surgical treatment approach demonstrates effectiveness in preserving endodontically treated molars with VRF, but its long-term treatment results for various VRF of molars need further randomized and controlled clinical investigations. Full article

Background/Objectives: The present study aims to assess the success rate of a CAD/CAM nickel–titanium wire (Memotain^®) used as a fixed orthodontic retainer, over a one-year period. Methods: A retrospective study was conducted on 338 CAD/CAM nickel–titanium (Memotain^®) fixed retention wires in 205 patients, bonded by a single experienced operator between January 2017 and December 2020. Follow-up visits were scheduled 6 (T1) and 12 months (T2) post-bonding. At each follow-up visit, events (defined as debonding, breakage, retainer loss, or tooth displacement) were classified by tooth, and success or failure of the retainer was determined based on the presence or absence of these events. Results: For the mandibular arch at T1 (6 months), the success rate was 85%, with debonding (n = 46) being the only event observed. At T2 (12 months), the success rate was 77%, with debonding (n = 30), wire breakage (n = 5) and retainer loss (n = 18) having occurred. For the maxillary arch, the overall success rate was 83% at T1 and 78% at T2. Debonding was the most common event observed over the 12-month observation period (n = 29), followed by retainer loss (n = 20) and wire breakage (n = 3). The overall success rates per type of tooth in the upper arch were 86% for the premolars, 96% for the canines, 95% for the lateral incisors and 93% for the central incisors. For the mandibular arch the success rates were 92% for the premolars, 97% for the canines, 96% for the lateral incisors and 94% for the central incisors. Conclusions: CAD/CAM nickel–titanium fixed retainers (Memotain^®) demonstrated promising 1-year survival rates in both arches, though long-term multicentre studies are needed to confirm their reliability. Full article

Background/Objectives: Stability, retention, and support are removable partial denture (RPD) biomechanical principles. The literature shows contradictory opinions on indirect retention in RPDs, but no solid scientific evidence exists. This in vitro research aims to analyze indirect retainers’ (IRs) influence on forces transmitted to abutment teeth of a Kennedy Class I mandibular RPD. Methods: Bilateral distal-extension mandibular RPDs—differing only in the presence or absence of an IR on tooth 44 (IR model vs. nonIR model, respectively)—were installed on an acrylic master model. Tensile forces were applied perpendicularly to the occlusal plane on the longest free-end saddle’s distal aspect. Electronic speckle pattern interferometry (ESPI) measurements were obtained with and without an IR. The three-dimensional out-of-plane displacements of both models were acquired. Results: Abutment teeth 46 and 47 contralateral to the longest distal extension suffered more deformation under displacement forces when an IR was used. In turn, the IR’s influence on the deformation values of the abutment tooth 34 adjacent to the larger edentulous area depended on the intensity of the tensile force exerted: low-intensity forces resulted in reduced deformation, while higher-intensity forces resulted in higher deformation. Conclusions: This study’s findings indicate that indirect retention promotes better tensile force distribution in the existent teeth. However, they also question the IR’s role in protecting abutment teeth against excessive torque forces. This study’s preliminary results highlight the need for research on indirect retention principles using new methodologies, namely, in silico and ex vivo studies, and their experimental and clinical validation. Full article

The separation of walnut kernels from shells is a crucial step in walnut processing. Pneumatic sorting is the mainstream method. However, due to the overlapping suspension speeds of half-shells and eighth-shells, complete separation was not achieved. This paper proposes using a toothed vibrating screen to separate the two. Using EDEM to simulate and analyze the motion forms, collision processes, and stress conditions of walnut shells and kernels on the vibrating screen, the effectiveness of this method was demonstrated, and the mechanisms of shell–kernel retention and loss during the separation process were revealed. Results indicate that 1/8 kernels, being smaller, easily fall into tooth grooves and move upward step by step under the excitation force during reciprocating vibration. The 1/2 shells, being larger, are difficult to fall into the teeth grooves, and their smooth surfaces cause them to slide easily, moving downward continuously under the action of reciprocating vibration and gravity. Using the cleaning rate and loss rate as evaluation indicators, it was found that as the inclination angle of the vibrating screen increased step by step, the cleaning rate consistently increased monotonously. The loss rate initially rose slowly, then surged sharply after reaching 22°, at which point the loss rate was at its lowest, around 10%, and the cleaning rate was at its maximum, at 95%. The shortest retention time of walnut shells on the screen is 2.85 s, and the longest is 10.6 s, with the number of collisions being 458 and 2619, respectively; the collisions between the shells and the kernels account for 51.8%. The failure to thoroughly separate is due to the shell and kernel entangling within the separation area, making it impossible to segregate them. They enter the opposite region, collide, and cause loss and retention phenomena. Full article