Search

Purpose: To describe a digital workflow for the management of the emergence profile and the restoration's finishing line on vertically prepared teeth using a digital data set. Materials and Methods: Three scans (the prepared teeth the day of the preparation, the provisional restoration placed on the preparation after soft tissue maturation, and the provisional restoration outside of the oral cavity) were combined under a common data set to provide the necessary information to design the final restoration. Results: The digital technique presented can facilitate the implementation of the vertical preparation, because the desired finish line can be defined by the clinician and be transferred predictably to the dental lab. The current approach provides an alternative gingival management method, taking advantage of the displacement of soft tissue after vertical preparation. Conclusions: Positioning of the final finishing line on vertically prepared teeth, management of soft tissue, and fabrication of the final restoration can be facilitated with this approach, combining a digital data set that has been obtained during a distinct phase of the treatment. [ABSTRACT FROM AUTHOR]

This case series investigated the effect of a combination therapy utilizing connective tissue graft (CTG) in the treatment of periodontal regeneration of mandibular Class III/IV furcation involvement (FI). Six patients diagnosed with periodontitis stage III or IV (grade A to C), presenting with Class III or IV FI, were treated with fibroblast growth factor-2 and carbonate apatite in combination with CTG. The following clinical parameters were evaluated at baseline and after 6, 12, and 18 months: periodontal probing depth, clinical attachment level, furcation invasion, radiographic vertical defect depth, and gingival phenotype. Significant improvements in clinical parameters were observed in all treated FI sites. Four Class III defects and one Class IV defect obtained complete closure, and one Class IV defect was improved to Class I. This case series showed the potential of administering combination regenerative therapy for changing the prognosis of hopeless teeth with severe furcation defects. [ABSTRACT FROM AUTHOR]

Purpose: To compare the volumetric loss of clinical crown structure in commonly encountered clinical situations for monolithic ceramic crowns, occlusal overlays, and partial-coverage onlays. Materials and Methods: Typodont teeth made with preexisting mesio-occlusodistal (MOD) preparations for mandibular first molars and maxillary first premolars were prepared with three different preparations: a full-contour monolithic zirconia crown, a lithium disilicate occlusal overlay, and mesio-occlusodistobuccal/mesio-occlusodistolingual (MODB/MODL) lithium disilicate onlays for premolars and molars. 3D-metrologic software was used to evaluate the volumetric loss of clinical crown structure for each preparation type. Subsequently, the mesiolingual cusps of mandibular molars and buccal cusps of maxillary premolars were excluded for a separate analysis to simulate patient presentation with an existing restoration and sheared-off cusp. Results: Full-coverage monolithic zirconia crowns removed 45.37 to 219.53 mm³ of the remaining clinical tooth structure, depending on the clinical scenario and tooth position, while lithium disilicate overlays removed 27.48 to 105.13 mm³ and MODB/MODL lithium disilicate onlays removed 5.48 to 47.45 mm³. In each scenario tested, MODB/MODL onlays removed significantly less clinical crown structure than overlays (P < .001); both MODB/MODL onlays and overlays removed significantly less structure than full-coverage crowns (P < .001). Conclusions: Monolithic zirconia crown restorations require significantly more removal of remaining tooth structure than lithium disilicate occlusal overlays and partial-coverage onlays for commonly occurring clinical situations requiring indirect restorations. [ABSTRACT FROM AUTHOR]

Purpose: To study the influence of tooth mobility on the accuracy of conven6onal impressions. Materials and Methods: In total, 10 pa6ents with mobile anterior teeth and 10 healthy pa6ents were treated with conven6onal impressions and intraoral digital impressions. The digital impression group was recorded as standard data, the mobile teeth group was recorded as the experimental group, and the healthy anterior teeth group was recorded as the control group. We imported digital impression and irreversible hydrocolloid impression files into Geomagic Wrap and marked reference points to execute N-point alignment, then we recorded the coordinates. Paired-samples t test was used to analyze whether the point coordinates of mobile teeth were statistically significant (α = .05). One-way ANOVA was used to analyze whether there was a rela6onship between coordinate differences and tooth mobility in the distal, coronal, and buccal directions (α = .05). Results: In the buccal and coronal directions, the difference was statistically significant between the conven6onal and digital impression groups. In the buccal direction, the accuracy differences of I-degree and II-degree mobile teeth were 0.149 mm and 0.401 mm, respectively. In the coronal direction, the differences were 0.128 mm and 0.233 mm, respectively. Meanwhile, ANOVA analysis showed that there was a rela6onship between point coordinate difference and tooth mobility in the buccal and coronal directions. Conclusions: Conventional impressions can influence the accuracy of mobile tooth impressions. Therefore, digital impressions should be adopted for mobile teeth impressions. [ABSTRACT FROM AUTHOR]

Autotransplantation has been proven as a viable method of reconstructing missing teeth. While preparing the recipient site, the bone reduction location depends largely on the surgeon's experience. Inappropriate overpreparation can cause biologic and esthetic complications, such as buccal or lingual bone resorption. This paper provides an innovative method to aid clinicians in precisely preparing a recipient site with the assistance of medical image-processing software and a real-time navigation system. This case report presents the autotransplantation of a mandibular molar using this technique with good short-term (6 months) clinical outcomes, including radiographic bone fill, normal probing pocket depth, physiologic tooth mobility, acceptable gingival level, and satisfactory restoration. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this retrospective study was to assess the short- to mid-term restorative and periodontal outcome of deep margin elevation (DME) performed using resin composite. Materials and Methods: Twenty-eight teeth treated with DME and indirect adhesive restorations were followed-up for a mean of 25.4 months (minimum: 12 months). Clinical and radiographic examination assessed the adaptation of the DME material and indirect restorations, presence of recurrent caries or discoloration, periodontal health at DME and non-DME sites, and periapical health. Results: The overall success rate was 96.6%. One tooth showed signs and symptoms of apical pathology after 34 months following DME. No caries, discoloration, or periodontal pockets were detected in any of the treated teeth. DME had no detrimental effect on the gingival/periodontal health or plaque accumulation. There was no correlation between the distance from the DME material to the marginal bone level and pocket depth, gingival inflammation, and plaque accumulation (p > 0.05). Conclusion: Deep margin elevation might be considered a safe procedure for teeth with deep subgingival proximal caries in the short- and mid-term. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of milled versus 3D-printed complete denture bases and teeth and to assess the position of the teeth in relation to the corresponding denture bases. Materials and Methods: Two different manufacturing techniques were used in this study. In Group A, 10 complete dentures were digitally designed and fabricated by milling prepolymerized blocks of polymethyl methacrylate (PMMA). In Group B, 10 complete dentures were digitally designed and fabricated using a 3D-printing technique. The accuracy of the maxillary and mandibular denture bases and teeth and the positions of the teeth in relation to the corresponding denture bases were evaluated using Geomagic Control X software (Oqton). Data were presented as mean and SD values. Statistical analysis of the resultant data was performed using Student t test. The significance level was set at P = .05. Results: With regard to denture bases, lower surface deviation values were found in the maxillary and mandibular milled denture bases (Group A), with values of 0.158 ± 0.024 and 0.117 ± 0.022, respectively. However, regarding the denture teeth, lower surface deviation values were found for printed teeth (Group B), with values of 0.18 ± 0.016 for the maxillary teeth and 0.153 ± 0.02 for the mandibular teeth. For positioning of the teeth in relation to the corresponding denture bases, the values were 0.4 ± 0.08 for the maxillary teeth and 1.003 ± 0.027 for the mandibular teeth. Conclusions: The milling technique yields complete denture bases with superior accuracy, whereas printing technology produces denture teeth with better accuracy and positioning in the corresponding denture bases. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of post length, post material, and substance loss on the fracture resistance of endodontically treated mandibular premolars. Materials and Methods: A total of 96 extracted human mandibular first premolars were endodontically treated and divided into 12 test groups (n = 8 each) based on the number of residual walls (one/two), post material (glass-fiber/titanium), and post length (5 mm, 7.5 mm, and 10 mm). After luting the posts, specimens received a composite resin core and a crown preparation with a 1.5-mm ferrule. Cast cobalt-chromium crowns were cemented using glass-ionomer cement. After 1,200,000 chewing cycles with a load of 49 N and simultaneous thermocycling (5°C to 55°C), specimens were quasi-statically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed using three-way, two-way, and one-way ANOVA (a = .05). Fracture modes were examined under a stereomicroscope (×25 magnification) and recorded. Results: The mean ± SD fracture loads ranged from 642 ± 190 N (one wall, glass fiber, 5 mm) to 1,170 ± 130 N (two walls, titanium, 7.5 mm). The mean fracture load of titanium posts was significantly higher than that of glass-fiber posts (P < .001), and the 7.5-mm post length exhibited significantly higher fracture loads than groups with 5-mm and 10-mm post length (P = .008). Conclusions: Teeth restored with titanium posts revealed considerably higher fracture resistance than teeth restored with glass-fiber posts, especially if 7.5-mm-length posts were used. [ABSTRACT FROM AUTHOR]

This paper investigates tool deflection and its compensation in Drill Thread Milling (DTM), a novel method for internal thread fabrication. The study proposes a heuristic model that integrates lateral force estimation and soft collision techniques to counteract tool deflection. The model's effectiveness was validated through extensive experiments across various cutting conditions, workpiece materials, and thread sizes. Results indicate that feed per tooth significantly affects tool deflection more than cutting speed, and low machinability materials exhibit greater deflection. Larger thread sizes also lead to increased deflection due to higher cutting forces. The proposed compensation method effectively reduces deflection, ensuring the resulting threads meet specified standards. This study provides valuable insights for optimizing DTM processes, improving precision, and enhancing manufacturing efficiency. [ABSTRACT FROM AUTHOR]

This study utilised a prototype system which consisted of a person-specific 3D printed jaw tracking harness interfacing with the maxillary and mandibular teeth and custom jaw tracking software implemented on a smartphone. The prototype achieved acceptable results. The prototype demonstrated a static position accuracy of less than 1 mm and 5°. It successfully tracked 30 cycles of a protrusive excursion, left lateral excursion, and 40 mm of jaw opening on a semi-adjustable articulator. The standard error of the tracking accuracy was reported as 0.1377 mm, 0.0449 mm, and 0.9196 mm, with corresponding ${r^2}$ r 2 values of 0.98, 1.00, and 1.00, respectively. Finally, occlusal contacts of left, right, and protrusive excursions were tracked with the prototype system and their trajectories were used to demonstrate kinematic modelling (no occlusal forces) with a biomechanical simulation tool. [ABSTRACT FROM AUTHOR]

Megalolamna is an extinct lamniform shark genus that is known from Miocene marine deposits. In this study, three new specimens of Megalolamna collected from the eastern USA are newly described, and the diagnosis of the genus is emended to include a previously undocumented dental characteristic. The new specimens are represented by one tooth from the upper Oligocene Chandler Bridge Formation in South Carolina and two isolated teeth from the lower Miocene Calvert Formation in Maryland. The specimens from the Calvert Formation represent the northern-most occurrence of Megalolamna. Although the taxonomic identification of the specimen from the Chandler Bridge Formation is somewhat tentative, it is considered to represent geologically the oldest record of Megalolamna, suggesting the likelihood that the enigmatic genus has its origin in the Palaeogene no later than 23.5 Ma. [ABSTRACT FROM AUTHOR]

Age determination of bottlenose dolphins (Tursiops truncatus) is a critical tool in understanding both individual and population health. There are many methods of aging bottlenose dolphins including analysis of teeth, pectoral flipper radiographs, and epigenetics. The most common and oldest method for aging toothed cetaceans is the counting of growth layer groups (GLGs) in the teeth. Current techniques have technical and repeatability challenges. Therefore, a processing technique that results in better resolution of GLGs is needed. This study compares different decalcifications and different histochemical staining techniques. Decalcification was done using 10% EDTA, Kristensen's decalcification, and Rapid Decalcification Solution (RDO). Following decalcification and routine processing, GLGs were assessed using Hematoxylin and Eosin (H&E), hematoxylin, Giemsa, Wright-Giemsa, Toluidine Blue (T-Blue), Masson's Trichrome, and Congo Red staining techniques. Decalcification with Kristensen's and staining with Masson's Trichrome and Congo Red were determined to best highlight GLGs. This processing and staining was then applied to a sample population of 102 bottlenose dolphins that were evaluated independently and blindly by two observers. Of the 102 dolphin samples, 13 (12.7%) were unable to age due to no clear distinction or distortion between GLGs. [ABSTRACT FROM AUTHOR]

The outcrops of the Duwi Formation (Late Campanian in age) in the Maghrabi-Liffiya sector of the Abu-Tartur Plateau have produced numerous chondrichthyan teeth. Forty-nine isolated teeth represent two different species: Scapanorhynchus rapax and Cretoxyrhina mantelli. The majority of the teeth were found within a yellow phosphate bed and with the rest contained within the black phosphate bed. The teeth were collected mainly through surface sampling. The Duwi Formation marks the onset of fully marine conditions in Egypt coinciding with the region’s major marine transgression during the Late Cretaceous. This paper reports the first description of Lamniformes from the southwestern desert of Egypt and records the youngest discovery of Cretoxyrhina mantelli in Africa and the Middle East and perhaps the youngest worldwide. [ABSTRACT FROM AUTHOR]

Aim: To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR. Methods: Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing). Results: The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy. Conclusions: There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases. [ABSTRACT FROM AUTHOR]

Biting is a common male–male combat tactic across jawed vertebrates, in which teeth or bony beaks serve as weapons. Because biting can cause severe injuries in some species, bite scars provide critical information about the degrees and patterns of fights.Amphibians have a remarkable diversity in tooth morphology and arrangement. However, the functional ecology of amphibian teeth is poorly studied. For example, unlike aquatic suction‐feeding frogs that lost teeth, aquatic salamanders that suction‐feed prey retain numerous sharp teeth, suggesting that teeth as weapons may partially explain their retention.Here, we analysed long‐term injury records of one of the fully aquatic, suction‐feeding salamanders (Japanese Giant Salamander, Andrias japonicus) to examine the previously unexplored potential of amphibian teeth as weapons for male–male combat. The majority of the injuries were missing toes and limbs, which most likely occurred during intra‐specific combat. We explored associations between injuries and independent variables such as sex, body size, body condition and stream sections. We also investigated possible injury‐pattern biases along the lateral (i.e. right vs. left) and longitudinal (i.e. anterior vs. posterior) axes, which could reveal how these animals fight.We found that males had more injuries, larger individuals had more injuries, and males with poorer conditions had more injuries. There was no association between injuries and stream sections. In addition, we found that salamanders had more injuries on the right and posterior sides of the body. The lateral asymmetry in injuries is likely associated with turning asymmetry during combat.Our results revealed the intense male–male combats of giant salamanders, providing evidence of the use of teeth as weapons. Combats via biting in amphibians may be much more common and severe than currently known. Our research suggests the function of amphibian teeth as weapons, which is likely to be a vital selective agent shaping its remarkable diversity. [ABSTRACT FROM AUTHOR]

For the sake of improving climbing ability of railway vehicle, gear-rack system is added to traditional vehicle to form rack vehicle. Aiming at the influence of the different gear-rack systems on the rack vehicle dynamic behavior, this article considers the gear-rack meshing impact based on the analysis of the generation mechanism of the gear-rack meshing excitation. The gear-rack meshing model and four kinds of rack vehicle coupled dynamics models are established, and the model is verified by experiments. Based on the model, the gear-rack nonlinear meshing behavior and rack vehicle dynamics characteristic of two kinds of Strub system, double row teeth Abt system and Locher system under different slopes is explored. and the dynamic characters of the rack vehicle system is analyzed. Finally, the optimal gear-rack system is obtained by comparing the dynamic behavior of different vehicles. The results show that: The dynamic behavior of rack vehicles with different gear-rack systems is significantly different, and Locher system has the optimal dynamic behavior. The gear-rack nonlinear meshing behavior and the vehicle safety of the coaxial Strub system and the double row teeth Abt system are poor, which are obviously affected by the track irregularity. The impact of the gear-rack nonlinear contact force of the coaxial Strub system reaches 29.8 kN. The maximum wheel/rail vertical force of the double row teeth Abt system reaches 51.4 kN. The vehicle stability of the different shaft Strub system is the worst, and the maximum stability index is 1.368. The conclusion of this paper provides theoretical support for the design and safe operation and maintenance of the world's mountainous rack railway. HIGHLIGHTS: Considering the disturbance effect of gear-rack meshing impact and wheel/rail dynamic contact behavior, a complete dynamic model of rack vehicle is established based on multi-body dynamics. The influence of the different kinds of gear-rack system on the dynamic characteristics of rack vehicle and nonlinear meshing behavior of driven gear-rack system are explored. [ABSTRACT FROM AUTHOR]

Objectives: We report the discovery and description of three human teeth from the Middle Paleolithic archaeological levels of Arbreda Cave (Serinyà, Catalonia, NE Iberian Peninsula). Materials and Methods: The teeth, two molars (one right dm2 and one right M2) from Level N (older than 120 kyr) and one P3 from Level J (dated between 71 and 44 kyr), were morphologically described based on microCT images and compared with Neanderthal and Homo sapiens specimens. Results: The teeth belong to a minimum of three individuals: one adult and one infant from Level N and one juvenile from Level J. The premolar from Mousterian Level J, the best preserved of the three teeth, exhibits characteristics to those from our comparative sample of Homo neanderthalensis, such as the crown measurements, EDJ traits, enamel thickness and volume of the pulp cavity. Discussion: In contrast to the clear Neanderthal characteristics observed in the P3 from Level J, the high degree of dental wear and poor state of preservation precludes definitive taxonomic designations of the two teeth from Level N. However, the crown dimensions and some tissue proportions are consistent with a probable assignation to Homo neanderthalensis. The teeth from Level N come from a context of long and recurrent occupations of the cave, whereas the archaeological context of the tooth from Level J is indicative of short and seasonal occupations of the cave, which may indicate a change in the lifestyle strategies of the last Neanderthals of the Iberian Peninsula. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to examine and compare the efficacy of mouthwashes containing different proteins and peptide on the prevention of enamel erosion in vivo, as well as to evaluate the participants’ satisfaction with the formulations. Methods: Twelve participants were selected and underwent five cross-over mouthwash phases: Water (control); 0.1 mg/mL CaneCPI-5; 0.5 mg/mL MaquiCPI-3; 0.1 mg/mL CsinCPI-2; and 0.037 mg/mL Stn15pSpS. After prophylaxis, the participants rinsed (1 min), followed by the acquired enamel pellicle (AEP) formation (2 h). An erosive challenge was made (biopsy, citric acid 1%, 15s) on the buccal surface of the central maxillary incisors. The Relative Surface Reflection Intensity (%SRI) was assessed and analyzed by ANOVA/Tukey’s tests. The calcium release in acid was measured by the Arsenazo method and verified by Kruskal-Wallis/Dunn’s tests. The Spearman’s correlation was used between analyses. A questionnaire evaluated the satisfaction of participants. Results: For both analyses, the results showed that mouthwashes containing the proteins or peptide were significantly more effective in preventing enamel erosion compared to deionized water, with no significant differences among the active ingredients (p < 0.05). Also, there was a significant negative correlation between %SRI and calcium released (r=-0.5754). The questionnaire revealed that the volunteers were satisfied with the taste of the products. In addition, the experimental procedures were well tolerable, and no side effects were reported. Conclusion: All mouthwashes containing proteins or peptide were acceptable and effective in protecting enamel against initial dental erosion in vivo. Clinical significance: This study highlights the potential of these pioneer organic components for the development of mouthwashes designed for people with risk of erosive tooth wear. [ABSTRACT FROM AUTHOR]

The Triassic record of modern sharks, rays, and skates (Elasmobranchii) is scattered and geographically biased towards the Northern Hemisphere and Europe in particular. Here, we report the first Triassic elasmobranch teeth from the Southern Hemisphere, originating from Norian strata of New Zealand. The teeth are few in numbers but relatively well preserved and indicate the presence of three different taxa, that all can be included in the extinct order Synechodontiformes. Different dental characters and combinations of characters suggest that the teeth represent previously undescribed species with apparently no close relatives in the Triassic elasmobranch record from the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

Background/Aim: Crown fractures are common traumatic dental injuries and tooth fragment reattachment is a viable option for restoring a fractured tooth. The aim of this study was to assess the knowledge and experience of dentists in the Federal District regarding the tooth fragment reattachment technique for enamel and dentin fractures. Materials and Methods: For the cross‐sectional observational study, an electronic form was designed with objective and self‐report questions for dentists. The data were analyzed using descriptive statistics, with their absolute and relative frequencies. For the analysis of categorical variables, the nonparametric chi‐squared or Fisher exact association tests were used in the statistical software R (version 4.2.1). Results: A total of 416 dentists participated in the study (58.9% female and 41.1% male). Of these, 70% declared they knew about fragment reattachment, but only 42.3% reported previous experience with this procedure. The most common storage medium used for the fractured fragment was milk (78.1%), and the bonding material used for reattachment was light‐cured composite resin (86.3%). A majority (66.3%) reported that for a patient with enamel and dentin fracture, with the crown fragment in good condition, they would choose to do the reattachment. Conclusion: Dentists demonstrated that they had adequate knowledge about the tooth fragment technique, although many did not have previous experience with this procedure. [ABSTRACT FROM AUTHOR]

Background/Aim: This study aims to evaluate the precision and efficacy of utilizing computer‐aided design (CAD) in combination with three‐dimensional printing technology for tooth transplantation. Material and Methods: This study analysed 50 transplanted teeth from 48 patients who underwent tooth transplantation surgery with the aid of CAD and positional guides. A consistent coordinate system was established using preoperative and postoperative cone‐beam computed tomography images. Linear displacements and angular deviations were calculated by identifying key regions in both virtual designs and actual transplanted teeth. Additionally, an analysis was conducted to explore potential factors influencing these deviations. Results: The mean cervical deviation, apical deviation, and angular deviation among the 50 transplanted teeth were 1.16 ± 0.57 mm, 1.80 ± 0.94 mm, and 6.82 ± 3.14°, respectively. Cervical deviation was significantly smaller than apical deviation. No significant difference in deviation was observed among different recipient socket locations, holding true for both single‐root, and multi‐root teeth. However, a significant difference was noted in apical deviation between single‐root and multi‐root teeth. Our analysis identified a correlation between apical deviation and root length, leading to the development of a prediction model: Apical deviation = 0.1390 × (root length) + 0.2791. Conclusions: The postoperative position of the donor teeth shows discrepancies compared to preoperative simulation when utilizing CAD and 3D printed templates during autotransplantation procedures. Continual refinement of preoperative design is a crucial endeavour. [ABSTRACT FROM AUTHOR]

Low-angle straight tooth face gear transmission has significant advantages such as compact structure, small axial force, good shunt effect, and insensitivity to installation errors, demonstrating great superiority in the main reduction and torque distribution structure of helicopters. In this paper, the calculation of cutting force in the process of gear turning is studied, and the mathematical model of low-angle straight tooth face gear is established, and the numerical calculation and simulation analysis of cutting force are completed. On this basis, the gear machining test was completed on the gear machine, and the actual cutting force was collected, which verified the correctness of the cutting force calculation method and the feasibility of the cutting force optimization scheme, and provided a new solution for the cutting force calculation of the low-angle straight tooth face gear machining in industrial production. [ABSTRACT FROM AUTHOR]

In micro-milling process, the prediction of cutting forces is important for investigating the mechanism of material removal, optimizing the process parameters, and monitoring the machining process. To improve the modelling accuracy, this paper proposes a novel instantaneous uncut chip thickness (IUCT) model that considers the elastic recovery accumulation (ERA) in the micro-milling process. It thus includes the phenomenon of varying IUCT at the current tool tip due to the elastic recovery of the previous tool tip during tool rotation. When the IUCT is less than the minimum uncut thickness (MUCT), the height of the elastic recovery can be increased due to the effect of ERA, while the height keeps constant after IUCT reaches above MUCT. Three cases of ERA are presented by comparing the feed per tooth with both tool runout and MUCT. Finally, micro-milling experiments have been conducted to verify the proposed cutting force model. In comparing with the measured cutting forces, it is shown that the predicted cutting forces with the ERA considered exhibit a much better accuracy than that without the ERA considered. When the feed per tooth is at a small amplitude, the improvement of the cutting force prediction accuracy becomes even more significant. [ABSTRACT FROM AUTHOR]

Nonreplications of previously undisputed phenomena tend to leave a theoretical vacuum. This theoretical perspective seeks to fill the gap left by the failure to replicate unobtrusive facial feedback. In the emblematic original study, participants who held a pen between the teeth (i.e., requiring activity of the zygomaticus major muscle) rated cartoons more positively than participants who held the pen between the lips. We argue that the same social mechanisms (e.g., the presence of an audience) modulate facial feedback to emotion as are involved in the feed-forward shaping of facial actions by emotions. Differing social contexts could thus help explain the contrast between original findings and failures to obtain unobtrusive facial feedback. An exploratory analysis that included results only from (unobtrusive) facial-feedback studies without explicit reference to emotion in the facial manipulation provided preliminary support for this hypothesis. Studies with a social context (e.g., due to experimenter presence) showed a medium-sized aggregate facial-feedback effect, whereas studies without a social context (e.g., when facial actions were only filmed), revealed a small effect. Video awareness strengthened facial feedback considerably within an engaging social context, but seemed to reduce it without a social context. We provisionally conclude that a (pro-)social interpretation of facial actions facilitates feedback to (primarily positive) emotion, and suggest further research explicitly manipulating this context. [ABSTRACT FROM AUTHOR]

The prediction of churning power loss has been a difficult problem in the analysis of spur gears. Thus, an analytical prediction model based on the redefinition of churning power loss and energy transformation is proposed to estimate the churning power of spur gears. Churning power loss is defined as the combination of the power loss due to the drag on the end face, the power loss due to the tangential flow, the power loss due to the acceleration of lubricants in the tooth space, and the power loss due to the centrifugal force. Several comparisons of prediction and experimental results are made and good agreement of those is obtained. Finally, the components of churning power loss under different gears and work conditions are analyzed, and the influences of each part on churning power loss are obtained. [ABSTRACT FROM AUTHOR]

The rotary percussive drilling tool was designed to improve rock-breaking efficiency, and the tool's cyclic frequency and stress-wave frequency are the key influencing factors on the rate of penetration, but the correlative research reports are few. In view of this situation, the cyclic frequency of the rotary percussion drilling tool and the frequency of stress waves generated during impact were measured. A numerical model of polycrystalline diamond compact (PDC) cutter cutting hard rock was established, and the measured frequency parameters were imported into the numerical model. The effects of cyclic frequency and stress-wave frequency on the penetration depth, rock breaking volume, and rock debris size were studied. The finding demonstrated that the average penetration depth increased with the increase of cyclic frequency, and decreased with the rise in stress wave frequency. When the two parameters were simultaneously high, it was conducive to generating smaller rock cuttings and wellbore cleaning. When the cyclic frequency was high and the stress wave frequency was low, the effect on the drilling tooth penetration was the best. The research results can provide a practical reference for optimizing the structure of rotary impact drilling tools and improving the penetration rate. [ABSTRACT FROM AUTHOR]

Sharks and their relatives are typically covered in highly specialized epithelial appendages embedded in the skin called dermal denticles; ancient tooth-like units (odontodes) composed of dentine and enamel-like tissues. These 'skin teeth' are remarkably similar to oral teeth of vertebrates and share comparable morphological and genetic signatures. Here we review the histological and morphological data from embryonic sharks to uncover characters that unite all tooth-like elements (odontodes), including teeth and skin denticles in sharks. In addition, we review the differences between the skin and oral odontodes that reflect their varied capacity for renewal. Our observations have begun to decipher the developmental and genetic shifts that separate these seemingly similar dental units, including elements of the regenerative nature in both oral teeth and the emerging skin denticles from the small-spotted catshark (Scyliorhinus canicula) and other chondrichthyan models. Ultimately, we ask what defines a tooth at both the molecular and morphological level. These insights aim to help us understand how nature makes, replaces and evolves a vast array of odontodes. [Display omitted] • Odontodes represent all tooth-like structures including teeth, internal and external denticles; sharks and their relatives have all types in various combinations depending on the species. • Many studies have attempted to understand the homology of tooth-like structures, sharks offer the opportunity to study both denticles and teeth within the same animal. • We describe the current knowledge on the developmental and structural differences between denticles and teeth in sharks, where the defining feature of oral teeth is the presence of a dental lamina. • Some sharks e.g. , hammerheads (Sphyrnidae), possess both oral (internal) and skin (external) denticles, which could shed light on the origin of odontodes debate, whether they first appeared inside or out. [ABSTRACT FROM AUTHOR]

Thanks to their exceptional diversity, teeth are among the most distinctive features of vertebrates. Parameters such as tooth size, shape, number, identity, and implantation can have substantial implications for the ecology and certain social behaviors of toothed species. Despite decades of research primarily focused on mammalian dentition, particularly using the laboratory mouse model, squamate reptiles ("lizards" and snakes) offer a wide array of tooth types and dentition variations. This diversity, which includes differences in size, shape, function, and replacement capacity, provides invaluable opportunities for investigating these fundamental properties. The central bearded dragon (Pogona vitticeps), a popular pet species with well-established husbandry practices, is of particular interest. It features a broad spectrum of morphs and spontaneous mutants and exhibits a wide range of heterodont phenotypes, including variation in the size, shape, number, implantation, and renewal of teeth at both posterior and anterior positions. These characteristics position the species as a crucial model organism for developmental studies in tooth research and for gaining deeper insights into evolutionary patterns of vertebrate dentitions. In this article, we provide an overview of the current understanding of squamate dentition, its diversity, development, and replacement. Furthermore, we discuss the significant advantages offered by squamate species as model organisms for investigating the evolutionary and developmental aspects of vertebrate dentition. [Display omitted] • Teeth are a hallmark features of vertebrates • Large ecomorphological diversity of squamate dentitions remains largely unexplored • Central bearded dragon is an emerging model for evo-devo and dental research • Squamate dentition: diversity, development, and replacement importance • Squamate models offer crucial insights into vertebrate tooth evolution [ABSTRACT FROM AUTHOR]

Open bite is a multifactorial problem, which is a challenging type of malocclusion for the orthodontist to treat. A careful and detailed diagnosis is important to ensure the correct treatment approach. With the use of temporary skeletal anchorage devices (TSADs), it is now possible in most cases to treat these malocclusions without surgical intervention. Several etiological factors are involved in the development of this malocclusion, including the patient's facial growth pattern, persistent sucking habits, tongue dysfunction, and mouth breathing due to compromised airways. These factors should always be identified early in a patient's life. Treatment strategies have included habit control, tongue crib, and correction of any airway problems, while in the more severe open bite patients, orthognathic surgery was necessary to correct the problem. Now, it can be treated by the intrusion of the posterior teeth using TSADs. This article presents one type of open bite resulting from condylar degeneration. In the past, this problem could have only been corrected with orthognathic surgery. Here, we demonstrate the result of an acquired open bite treated by intruding the posterior teeth with TSADs. In addition, we provide guidelines for selecting those cases that lend themselves to treatment with TSADs and those where combined orthodontic and orthognathic surgical correction is still needed. [ABSTRACT FROM AUTHOR]

The treatment with aligners is challenging especially because the overall accuracy of tooth movement is reported to be below 50 %. Moreover, dental anchorage provided by the Clear aligners (CA) is critical due to the third law of physics, where for every force action, there is an equal opposite reaction. CA associated with temporary skeletal anchorage devices (TSADs) are an effective treatment protocol for expanding the envelope of movement in complex cases. Extra-alveolar miniscrews associated with CA, are effective for retracting the maxillary (IZC) and mandibular dentition (MBS), while interradicular miniscrews provide excellent anchorage for incisor intrusion. Objective: The objective of the paper was to discuss the current biomechanics principles related to the use of CA associated with TSADs showcasing the treatment of complex cases, such as Class II, Class III, as well as deepbite malocclusions. [ABSTRACT FROM AUTHOR]

Anterior open bite (AOB) with mild-to-moderate skeletal discrepancies can be camouflaged by an orthodontic tooth movement. Conventional methods can improve occlusal relationships and some profile esthetics, but their mechanics may result in detrimental side effects such as a gummy smile, a high-frequency relapse, and an unfavorable facial profile. The emergence of temporary skeletal anchorage devices (TSADs) has facilitated the treatment of skeletal Class II AOB through intrusion of the posterior teeth and autorotation of the mandible, improving facial esthetics while minimizing the side effects. TSADs can also simplify treatment plans and offer a more predictable treatment result. Finite element studies have identified the location of the center of resistance of the dentition, providing a biomechanical basis for understanding 3-dimensional tooth movement patterns using TSADs. Therefore, biomechanical and clinical considerations are essential for correcting Class II AOB using TSADs. [ABSTRACT FROM AUTHOR]

Although traditional dental-implant approaches have served as primary solutions, they are limited by infection risks, complications, and prolonged failures. Hybrid electrospun nanofiber matrices based on biomaterials have emerged as compelling alternatives for dental-tissue regeneration, offering direct cell-matrix contact and facile modification to incorporate anti-inflammatory, angiogenic, antimicrobial, and osteogenic properties. In this review, we discuss the advancements in hybrid nanofiber matrix-based approaches in dental-tissue engineering over the past five years (2019–2023). Beginning with an exploration of dental tissues and tooth structures, we discuss the innovative strategies in each study, including fabrication methods, physicochemical and biological properties, and osteogenic potential. We anticipate that ongoing research will enable the widespread application of innovative biomaterials and nanofiber matrices in future dental therapies. [ABSTRACT FROM AUTHOR]

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The original publication on the Pliocene Otibanda Formation in Papua New Guinea briefly reported on crocodyliform fossils, including isolated teeth that were tentatively assigned to the notosuchian subclade Sebecosuchia. In this study, we reassess the crocodyliform material from the Otibanda Formation and provide the first detailed descriptions of the same, including the purported sebecosuchian teeth. Direct examination of these teeth confirms their ziphodont condition based on the labiolingual compression of the crowns and the presence of serrated mesial and distal carinae. In addition to the ziphodont teeth, there are also non-serrate conical teeth that are tentatively referred to an undetermined species of Crocodylus as well as fragmentary postcranial elements that we refer to as Crocodylia incertae sedis. Considering the geological age and geographical origin of the isolated ziphodont tooth crowns from Papua New Guinea, they are unlikely to belong to a sebecosuchian crocodyliform. Instead, it is more plausible that they are referable to Mekosuchinae, a highly diverse crocodylian clade inclusive of ziphodont forms that was prevalent on mainland Australia for most of the Cenozoic. [ABSTRACT FROM AUTHOR]

The vibration signal becomes impulsive due to the faults in bearings and gearboxes. A narrowband filter can detect an impulse-like event in a signal. The present work proposes a frequency-shifting narrowband filtering approach to extract the impulse information at multiple frequencies. Several narrowband-filtered signals from the vibration signal are obtained by frequency-shifting the signal and subsequently passing the frequency-shifted signals from a narrowband filter. The spectral mean and variance signals obtained from the envelopes at different frequencies capture the impulse information in the signal. The noise is uncorrelated across envelopes at different frequencies and gets nullified in the spectral signals. Thus, the proposed technique demonstrates a successful detection of the early stage and seeded faults in bearings from the IMS and CWRU datasets, respectively. The algorithm also reveals a clear distinction between healthy and damaged gearboxes through the analysis of NREL and in-house datasets, encompassing scuffing and chipped tooth faults, respectively. The present approach provides a robust condition-monitoring tool for bearings and gearboxes in industrial applications. [ABSTRACT FROM AUTHOR]

The clear aligner, commonly utilized in orthodontic treatment for malocclusion, necessitates the quantification of orthodontic forces, which is highly demanded by doctors for enhancing risk management and treatment efficiency. However, the current technology still faces obstacles in achieving conformal integration of pressure sensors onto clear aligners with large curvature for the quantification and real‐time monitoring of orthodontic forces. In this paper, a conformal iontronic sensing clear aligner (CSA) is proposed based on flexible iontronic sensing mechanism, which conformally integrates the sensor with the aligner to quantify orthodontic forces throughout the treatment process while preserving the aligner's original function. Specifically, the ionic coating is seamlessly integrated onto the diaphragm by applying a layer of ionic paint before molding the clear aligner, while the sensing electrode array, designed using a kirigami‐based structure, is seamlessly adhered to the ionic coating. By integrating the CSA into a dental model, its exceptional sensitivity and precise pressure mapping capabilities have been demonstrated. This enables the identification of various tooth movement patterns, discernment of orthodontic force magnitude, and continuous monitoring of forces throughout the orthodontic treatment. Consequently, this research is expected to significantly advance risk management, outcome prediction, and treatment efficiency in orthodontic treatments. [ABSTRACT FROM AUTHOR]

ABSTRACT Tooth fractures are a common consequence of dental trauma in young patients, requiring prompt and effective restorative interventions that ensure both functional integrity and esthetic appeal. Although resin stratification (layering) is the gold standard for achieving life‐like restoration of fractured teeth, many clinicians find it technically challenging due to the time and effort required for precise shade matching, concealing the fracture line, and accurate placement of resin composite layers with different levels of opacity. The more recent generation of monoshade composites, with their ability to adapt to various tooth shades, reduce the complexity of multi‐layer restorations, and improve chairside efficiency. Additionally, the composite cutback technique has gained attention as an effective method for restoring fractured teeth in young patients. This method combines the benefits of monoshade composites and the precision of simple additional layering to enhance both the esthetic and functional outcomes of the restorations. This mini‐review provides a comprehensive analysis of the composite cutback technique, the role of monoshade composites, and their clinical application in the restoration of fractured young teeth. [ABSTRACT FROM AUTHOR]

Traditional orthodontic treatment relies on subjective estimations of orthodontists and iterative communication with technicians to achieve desired tooth alignments. This process is time-consuming, complex, and highly dependent on the orthodontist's experience. With the development of artificial intelligence, there's a growing interest in leveraging deep learning methods to achieve tooth alignment automatically. However, the absence of publicly available datasets containing pre/post-orthodontic 3D dental models has impeded the advancement of intelligent orthodontic solutions. To address this limitation, this paper proposes the first public 3D orthodontic dental dataset, comprising 1,060 pairs of pre/post-treatment dental models sourced from 435 patients. The proposed dataset encompasses 3D dental models with diverse malocclusion, e.g., tooth crowding, deep overbite, and deep overjet; and comprehensive professional annotations, including tooth segmentation labels, tooth position information, and crown landmarks. We also present technical validations for tooth alignment and orthodontic effect evaluation. The proposed dataset is expected to contribute to improving the efficiency and quality of target tooth position design in clinical orthodontic treatment utilizing deep learning methods. [ABSTRACT FROM AUTHOR]

Dental restorative resin composites are widely used to repair tooth decay owing to attractive esthetics, adequate mechanical properties and minimally invasive tooth structure preparations. Nevertheless, dental restorative resin composites still face challenges because of their relatively high failure rate and short lifespan caused by secondary caries and bulk fracture. Thus, attempts have been carried out to explore a new generation of dental restorative resin composites with antibacterial, remineralizing, and self-healing capabilities to inhibit bacteria and lengthen the lifetime of the restorations. Such novel restorative composites can inhibit bacterial activity, reduce acid production, promote mineral regeneration and present a renewable advantage to achieve a higher performance, which are inspiring and provide support for further basic and clinical research. In this review, antibacterial dental restorative resin composites are first introduced, followed by remineralizing, self-healing, and multifunctional dental resin composites with two or more of the functions mentioned above. Meanwhile, we explain the mechanism of the corresponding dental restorative resin composites and describe their characteristics. Finally, we conclude and put forward prospects. This review will attract both researchers and clinicians in this field and help to provide innovative ideas to design new restorative resin composites for biomedical applications. [ABSTRACT FROM AUTHOR]

Introduction: Although with increasing popularity due to aesthetic appeal and comfort, clear aligners (CAs) are facing challenges in efficacy and predictability. Advancement in the underlying biomechanical field is crucial to addressing these challenges. This paper endeavors to provide a comprehensive framework for understanding the biomechanics of CA and enlightening biomechanics-based improvements on treatment strategies. Methods: A thorough review of the English-language literature accessible through PubMed and Google Scholar, without any publication year restrictions, was undertaken to unravel the biomechanical aspects of CA. Results: This review presented an up-to-date understanding of aligner biomechanics arranged by the framework of the material-dependent mechanical characteristics of CA, the geometric characteristics-dependent force transmission of the CA system, methods for studying the biomechanics of CA, and the biomechanical analyses for different types of tooth movement. Conclusions: Biomechanics should be the fundamental concern for concepts, methods and adjuncts attempting to enhance the accuracy and predictability of tooth movement induced by CA. Improvement on material properties and alteration of geometric design of CA are two main approaches to develop biomechanically optimized force system. Exploration of real-world force sensing and monitoring system would make substantial progresses in aligner biomechanics. [ABSTRACT FROM AUTHOR]

AbstractAnalysis of bearing capacity of seabed consolidation foundation is conducted. Two types of bearing capacity along the vertical and horizontal directions are derived. The stress distribution between tooth plates is analyzed using the slip line field theory, and the soil between the tooth plates is divided into wedge-shaped rigid zones, passive slip zones, and transition zones. The analysis results show that the ratio of tooth depth to tooth spacing significantly affects the formation pattern of the failure zone between the tooth plates. When the depth-to-spacing ratio is small, all three zones are present, while as the ratio gradually increases, the rigid wedge-shaped zone also increases, the transition zone becomes smaller, and the passive zone disappears. Therefore, it is advisable to arrange a smaller depth-to-spacing ratio to fully exploit the strength potential of the soil between the tooth plates. The results of the finite element method (FEM) analysis also show the existence of active and passive zones beneath the crawler tracks, and due to the combination of orthogonal loadings in the vertical and horizontal directions, there is a phenomenon of skewed stress bubbles in the foundation soil beneath and correctness of the derived bearing capacity of the foundation in this study. [ABSTRACT FROM AUTHOR]

To study the multilevel coupled vibration of a naval gun under the foundation motion excitation of the ship, a mechanical-electrical-hydraulic coupled dynamic model of the naval gun including the follow-up systems' influence was established. The subprogram for calculating the ship foundation motion was written by the harmonic superposition method, and the motion in the 3 and 5-scale sea waves was reconstructed, respectively. Based on the multidisciplinary simulation, the transmission characteristics of the ship's foundation motion excitation along the naval gun and the influence of the tooth arc arrangement on the stabilization accuracy of the naval gun are analyzed. The results show that: the foundation motion excitation of the ship will aggravate the imbalance of the contact forces at the left and right trunnions of the cradle. A bilateral symmetrical arrangement scheme of the tooth arcs can reduce the contact forces' imbalance at the trunnions and reduce the adverse influence on the stabilization accuracy of the naval gun. The relevant research provides theoretical support and technical guidance for the structural design or verification of the naval gun. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Overview Conclusions Clinical Implications To review the factors that impact the accuracy of intraoral scanners (IOSs) when fabricating tooth‐supported restorations.Factors can have a different impact on IOS accuracy depending on the scanning purpose. If the goal is to fabricate tooth‐supported restorations, it is essential to review the following operator‐related factors: IOS technology and system, scan extension and starting quadrant, scanning pattern, scanning distance, and rescanning methods. Additionally, it is critical to interpret the following patient‐related factors differently: edentulous spaces, presence of existing restorations on adjacent teeth, and characteristics of the tooth preparation (build‐up material, geometry, total occlusal convergence [TOC], finish line location, and surface finishing), and interdental spaces (between tooth preparations or between preparation and the adjacent tooth).For crown or short‐span fixed dental prostheses, a reduced scan extension is recommended. For complete‐arch scans, it is advisable to start the scan in the same quadrant as the preparation. If the IOS permits locking the scan, rescanning may be indicated. Restorations on tooth preparations and adjacent teeth reduce accuracy. The simpler the geometry and the larger the TOC, the higher the IOS accuracy. Intracrevicular finish lines result in lower accuracy than equigingival or supragingival positions. Air‐particle procedures showed better accuracy than coarse and fine grit and immediate dentin sealing. The greater the space between a preparation and the adjacent tooth, the better the accuracy.Dental professionals must understand and handle the factors that impact the scanning accuracy of intraoral scanners differently depending on the purpose of the scan. [ABSTRACT FROM AUTHOR]

Traditional dental prosthetics require a significant amount of work, labor, and time. To simplify the process, a method to convert teeth scan images, scanned using an intraoral scanner, into 3D images for design was developed. Furthermore, several studies have used deep learning to automate dental prosthetic processes. Tooth images are required to train deep learning models, but they are difficult to use in research because they contain personal patient information. Therefore, we propose a method for generating virtual tooth images using image-to-image translation (pix2pix) and contextual reconstruction fill (CR-Fill). Various virtual images can be generated using pix2pix, and the images are used as training images for CR-Fill to compare the real image with the virtual image to ensure that the teeth are well-shaped and meaningful. The experimental results demonstrate that the images generated by the proposed method are similar to actual images. In addition, only using virtual images as training data did not perform well; however, using both real and virtual images as training data yielded nearly identical results to using only real images as training data. [ABSTRACT FROM AUTHOR]

Objectives: To search for pathogenic gene of a family with non‐syndromic tooth agenesis, and explore the possible pathogenesis. Materials and Methods: A Chinese family with non‐syndromic tooth agenesis was recruited and screened for the pathogenic variants by whole exome sequencing technology and co‐segregation analysis. The subcellular localization of wild‐type and mutant protein was detected by immunofluorescence assay. Cycloheximide chase assay was performed to examine the difference in degradation rate between mutant protein and wild‐type one. Dual‐luciferase reporter assays were conducted to explore the alterations of mutant protein in the regulation of downstream target genes. Results: A novel missense variant of PAX9 (c.296C>A:p.A99D) was found in this family. Bioinformatics software showed β‐return and the random coil were shortened in the p.A99D. The variant did not affect the subcellular localization of PAX9, but the degradation rate of p.A99D was accelerated (p < 0.05). p.A99D inhibited the activation of downstream target gene BMP4 (p < 0.05). Conclusions: This novel variant expands the pathogenic gene spectrum. The variant impaired the protein structure, accelerated the degradation of protein, and inhibited the activation of the downstream target gene BMP4, an upstream molecule in the TGF‐β/BMP pathway, which may contribute to tooth agenesis in this family. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the role of Keratinocyte Differentiation Factor 1 (KDF1) in ectodermal dysplasia (ED) and nonsyndromic tooth agenesis (NSTA) and perform a literature review. Methods: Genome sequencing was used to identify genetic variants in a Thai, NSTA proband and validated through Sanger sequencing. Pathogenicity was assessed using ACMG guidelines, MetaRNN and AlphaMissense. A comprehensive review of KDF1/NSTA cases informed genotype–phenotype analysis of the proband. Results: The proband revealed multiple missing teeth, caries and extensive periodontal disease. Deep phenotyping showed no signs of ED beyond tooth agenesis. The identified novel KDF1 variant, p.Ile243Leu, was classified as 'likely pathogenic' by ACMG and predicted as 'detrimental' by MetaRNN and AlphaMissense analyses. A total of 14 reviewed KDF1 cases revealed ED‐associated variants (3 variants in 8 patients) clustering in the region of amino acids 251–275, within the DUF4656 domain, while NSTA‐causing variants (4 variants in 6 patients) were typically found in amino‐ or carboxy‐termini to this region. KDF1/NSTA cases exhibited an average of 15 missing teeth, with a higher prevalence in the mandible. Conclusion: This study identifies a novel KDF1 variant‐related NSTA in Thai people. The genotype–phenotype correlates suggest a distinctive pattern and tooth agenesis of KDF1‐related NSTA. [ABSTRACT FROM AUTHOR]

The fossil record of the southeastern Pacific Ocean has been scarcely studied compared to other regions. We present the detailed description of two pelagic shark species, Alopias vulpinus (common thresher) and Lamna nasus (porbeagle) (Elasmobranchii: Lamniformes), from the Neogene of South America. The fossil teeth described here were recovered from the Bahia Inglesa Formation in Caldera, northern Chile. Our study provides the first comprehensive descriptions of fossil remains of A. vulpinus from Chile and L. nasus from the Americas. The occurrence of the common thresher shark represents the first published record and description of a representative from the family Alopiidae in northern Chile, whereas the fossil remains of the porbeagle shark are recorded for the first time in Chile. This study contributes to the understanding of the past distribution of shark species in the Eastern Pacific of South America during the Neogene period. It further confirms the particular abundance of lamniform sharks in the Neogene of Chile. [ABSTRACT FROM AUTHOR]

The dredged soil encountered in dredging projects has become more and more complex, especially the SPT blowcounts of hard clay encountered in the construction of the deep water channel with trailing suction hopper dredger reaches 20,which is obviously different from the hard state of clay in previous channel dredging projects. In order to study the excavationmechanism of draghead tooth in hard clay, underwater fast cutting experiments were conducted on hard clay with SPT blowcounts of 18, 21, and 25 under different cutting speeds and depths to investigate the variation of draghead tooth cuttingresistance. By arranging the cutting resistance sensor on the draghead tooth, the underwater cutting resistance of the dragheadtooth under different cutting conditions was obtained, and the influence of cutting speed, cutting depth and SPT blow counts ofclay on the draghead tooth cutting resistance was analyzed respectively, which provides theoretical support for the design of thehard clay draghead. [ABSTRACT FROM AUTHOR]