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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]

Objectives: This study aimed to develop an artificial intelligence (Al) model that can determine automatic tooth numbering, frenulum attachments, gingival overgrowth areas, and gingival inflammation signs on intraoral photographs and to evaluate the performance of this model. Method and materials: A total of 654 intraoral photographs were used in the study (n = 654). All photographs were reviewed by three periodontists, and all teeth, frenulum attachment, gingival overgrowth areas, and gingival inflammation signs on photographs were labeled using the segmentation method in a web-based labeling software. In addition, tooth numbering was carried out according to the FDI system. An Al model was developed with the help of YOLOv5x architecture with labels of 16,795 teeth, 2,493 frenulum attachments, 1,211 gingival overgrowth areas, and 2,956 gingival inflammation signs. The confusion matrix system and ROC (receiver operator characteristic) analysis were used to statistically evaluate the success of the developed model. Results: The sensitivity, precision, F1 score, and AUC (area under the curve) for tooth numbering were 0.990, 0.784, 0.875, and 0.989; for frenulum attachment these were 0.894, 0.775,0.830, and 0.827; for gingival overgrowth area these were 0.757, 0.675, 0.714, and 0.774; and for gingival inflammation sign 0.737, 0.823, 0.777, and 0.802, respectively. Conclusion: The results of the present study show that Al systems can be successfully used to interpret intraoral photographs. These systems have the potential to accelerate the digital transformation in the clinical and academic functioning of dentistry with the automatic determination of anatomical structures and dental conditions from intraoral photographs. [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]

Smiling is an embodied and complex social act. Smiling is presented as facilitating individual health and wellbeing, but the value placed on smiling raises questions about structural conditions acting on the body. While smiling has been considered sociologically, psychologically and historically, we argue that further exploration of the embodied smile offers fruitful avenues for future research. This article attempts to advance understanding of the smile and its importance by: (I) Bringing together literature on smiling as a social act and smiling as embodied. (II) Systematically identifying key themes, which recognise sociological insights and the relevance of oral health. (III) Pointing to useful directions for future sociological research into smiling. In this article, we review literature on body techniques; impression management and social interaction; gender, race and smiling; and emotional, aesthetic and affective labour. We move on to embodiment, considering the mouth as a body project and in relation to the ageing body, before reflecting on the significance of oral health and dentistry. We highlight future directions for sociological research on smiling, building on eight interrelated and cross‐cutting themes: norms and expectations, aesthetic ideals, self and identity, health and wellbeing, body work, commodification and labour, inclusion and exclusion and resistance. [ABSTRACT FROM AUTHOR]

The treatment of mandibular deviation in a completely edentulous patient (after segmental resection of the mandible) without osseous reconstruction consists of a twin-table maxillary complete denture occluding with a mandibular segmental denture at deviated position. Salivary reservoirs incorporated into the maxillary complete denture provide a potential solution to the ill effects of xerostomia, which is the most common post-irradiation complication. Hereby, the authors presents a case report of 62-yearold male patient with a unique method of incorporating two salivary reservoirs: one in the center of the palatal surface and the second beneath the additional palatal row of prosthetic teeth, with an approximate capacity of 7 mL. The novel design includes a removable silicone lid with an escape hole, allowing the patient's tongue to control the release of the salivary substitute. It provided ease of removal of the lid, as well as cleaning and refilling of the reservoir. The design allowed area under the second row of teeth was utilised effectively without adding to the bulk of the denture. [ABSTRACT FROM AUTHOR]

Performing endodontic treatment on a tooth with an immature apex can be challenging due to the risk of irrigant extrusion beyond the apex. This narrative review investigates the over-apex extrusion of activated irrigants in teeth with open and immature apices and aims to provide crucial insights for practice and research. Two hundred fifty-two results were found from the electronic search. Sixteen duplicates were removed before selection, and 24 were excluded. Of the 212 remaining results, the full text was evaluated for eligibility. One hundred ninety-four results were excluded: in one hundred sixty-five, irrigant activation was not performed; twenty-nine were animal studies; in seven, irrigant activation was not performed to disinfect the canal. Finally, 13 studies were included. They cover a range of topics, from the types of irrigants used to the techniques of activation, and their findings contribute to our understanding of the risks and consequences of irrigant extrusion. All the activation techniques investigated can, to varying degrees, cause the irrigant to extrude beyond the apex. Extrusion may not always be clinically relevant; however, the consequences of excessive irrigant leakage from the apex are dangerous, so try to assess all the variables that may cause it and adopt techniques to reduce it. [ABSTRACT FROM AUTHOR]

Background: First permanent molars (FPM) are highly susceptible to decay before the age of 15. When they are severely affected, the decision between conservation and extraction arises, particularly considering the potential for the second permanent molar (SPM) to replace the FPM. This cohort study aimed to evaluate clinical practices regarding FPM pulp necrosis treatment in children aged eight to twelve in two hospital departments in the Paris region. A second objective was to evaluate the one-year outcomes of the two therapies. Methods: A retrospective analysis was conducted using computerized billing software to identify patients aged eight to twelve who underwent either extraction or root canal treatment (RCT). Data collected included sex, age, arch involved, number of decayed surfaces, presence of Molar Incisor Hypomineralization (MIH), presence of infection, and treatment type. Results: A total of 66 patients were included, representing 61 extracted teeth and 23 RCT. Three main decision criteria were identified: presence of MIH (p < 0.005), extent of decay (p < 0.05), and SPM Nolla's stage. A total of 48% of the patients were seen at one year. A total of 16 of the 32 extractions and five of the nine RCTs had favorable evolution (p = 1). Conclusions: The question of whether to perform RCT or extraction of necrotic FPM in children aged eight to twelve is difficult to assess. It appears that five criteria need to be considered before the decision: possibility of long-term sealed coronal reconstruction, SPM Nolla's stage, follow-up possibilities, arch concerned, and presence of third permanent molar. [ABSTRACT FROM AUTHOR]

(1) Background: This study aimed to compare the shaping abilities of modern minimally invasive endodontic systems using natural teeth and 3D-printed resin replicas. These replicas offer a standardized approach for studying root canal preparation while eliminating the variability and scarcity of natural teeth. (2) Methods: Eleven mandibular molars with Vertucci class IV anatomy and their 3D-printed replicas (n = 132 canals) were scanned using micro-CT before and after preparation with six rotary systems. Shaping abilities were assessed by comparing volume, surface area, and unprepared areas between natural teeth and their 3D replicas, focusing on the apical third. Statistical analysis included the Shapiro–Wilk test to assess data normality and ANOVA and t-tests to compare different endodontic systems. (3) Results: Both qualitative and quantitative analyses revealed high similarity between natural teeth and 3D replicas. No significant differences in volume or surface area were found except in the apical third, where 3D replicas showed slightly larger increases in volume. (4) Conclusions: 3D resin replicas closely mimic natural teeth and provide a practical tool for assessing the shaping abilities of endodontic systems. This study demonstrates that 3D-printed models are suitable for endodontic research, offering a standardized and accessible alternative to natural teeth. [ABSTRACT FROM AUTHOR]

Objectives: Whether gemination or fusion, double teeth are rare worldwide, including Africa based on few published data. New cases from the continent are tallied, and anomalies potentially associated with double teeth are identified. These findings should interest a range of dental researchers. Methods: The presence of double teeth was recorded in 97 modern and premodern North and sub‐Saharan African samples (5631 inds.). They and coexistent anomalies are described relative to published examples. Prevalence was estimated as possible, using a Poisson model for 95% confidence intervals (CI). Results: Three maxillary double teeth were identified: a primary left lateral incisor in a Nubian child (1938–1756 BC), permanent left central incisor in an adult Egyptian (3650–3500 BC), and permanent right central incisor in a modern (19th century) adult from Guinea. Each co‐occurs, respectively, with a talon cusp, peg lateral incisor and, in the latter individual, second premolar crown variation with rotation, and third molar dens evaginatus. Double tooth prevalence is 0.048% (CI 0.001%–0.270%), with regional variation, in premodern, and 0.000% in modern North Africans. It is 0.000% for premodern and 0.048% for modern sub‐Saharan Africans (0.008%–1.714%). Conclusions: The double incisors are comparable to other global examples, indicative of common developmental processes during odontogenesis. Prevalence is lower than published modern rates, to suggest some exceptionality in Africans as reported earlier for other dental variants. Finally, though circumstantial, double teeth and accompanying anomalies may share an etiology. Continuing research overall, and in Africa specifically, will promote an improved understanding of double teeth formation and expression. [ABSTRACT FROM AUTHOR]

Identifying the species of shark responsible for a bite on humans is both complex and important for understanding and managing the shark risk. Depending on the species, tiny teeth may or may not be present in the symphyseal space at the junction of the upper and lower half‐jaws. In the case of bites, these tiny teeth (if present) often leave specific marks that may enable species to be quickly and reliably distinguished. We first present the anatomo‐morphological characteristics of the jaws of the three most traumatogenic species for humans which are the white, tiger, and bull sharks. The white shark has no symphyseal teeth, while the tiger and bull sharks do. On the basis of three confirmed real case studies involving those species, we then show that for the white shark, the wide symphyseal space between the first two teeth of each jaw usually leads to wounds including the presence of (quite) large flesh flaps, without any tooth imprint. Conversely, wounds following bites made by the tiger and bull sharks will generally leave characteristic small imprints of symphyseal teeth, especially in the case of incomplete or superficial bites. Although not systematic, this diagnostic approach provides fast, reliable, and clean results. The discrimination between two species with symphyseal teeth can then be made on the basis of complementary anatomic information such as jaw curvature and details linked to the anatomy of the teeth themselves, as well as the ecological context. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Methods Results Conclusion The prognosis of an avulsed permanent tooth depends on the time elapsed from injury to replantation in the injured socket. Wide variability exists in the terminologies used to describe this period. Hence, the aim of this study was to identify and categorize the terminologies related to this aspect of tooth avulsion, grade the explanations provided by the authors, and develop a consensus about the most appropriate terminology through a Delphi approach.This study involved a scoping review to identify and analyze the terminologies. It was performed according to PRISMA‐ScR with a systematic search performed in PubMed, Scopus, EMBASE, LILACS, and Web of Science. The terminologies were extracted, categorized, and evaluated for correctness. On the basis of the results of the review and expert group discussion, an ideal terminology was proposed. A Delphi study with 20 global experts in dental traumatology was conducted to develop a consensus for the proposed terminology and its description.A total of 92 studies were included. They were distributed into five categories according to the terminology used: (a) dry period alone, (b) total period with dry and/or wet times, (c) extra‐alveolar period, (d) extraoral period, and (e) miscellaneous. The explanations provided were correct in 37.5% of the studies that used an extraoral period. In the Delphi study, the lowest scores were given to the term dry period. There was an agreement of 95% for the proposed terminology.A wide variation in terminologies was observed that could be distributed into five categories. The correctness of explanations was highest in the studies that described total periods with dry and wet times. The Delphi study revealed excellent agreement for the proposed term “total extra‐alveolar period,” with precise and clear recordings of both nonphysiologic (dry) periods and physiologic (wet) periods. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Methods Results Conclusions Statement of Significance To measure difference in tooth shade and color achieved via two different over‐the‐counter bleaching agents with and without their associated light‐emitting diodes (LEDs).A total of 84 extracted human anterior teeth were randomly divided into seven groups. Gypsum models were made with 6 extracted teeth in an arch form (n = 12; 2 arches/group). Samples were kept hydrated throughout treatment (25°C). Bleaching treatment followed manufacturers' instructions with at least 1‐h of rehydration between treatments. Control tooth arches were left untreated. L*a*b* values were measured with a Vita Easyshade (VITA North America, Yorba Linda, CA) three times per tooth using white and black backgrounds. ∆E (CIE 2000) was compared between and within treatment groups over time with ANOVA and post hoc Tukey (a = 0.05).Subgroup testing confirmed the data were normally distributed. Two‐way ANOVA showed significant interaction between product (Control, Crest, Snow) and treatment (light only, product only, light and product) on ∆E values for black (p‐value < 0.001, F = 15.28) and white (p‐value < 0.001, F = 13.62) backgrounds. Post hoc pairwise Tukey tests showed a significant effect of light‐and‐product treatments in contrast to light‐ or product‐only treatments. Repeated measures ANOVA of between‐treatment change (∆E) by product showed significant interaction between time and treatment for Snow products (p < 0.001, F = 10.9) and independent effects of time and treatment for Crest products (Time: p‐value < 0.001, Treatment: p‐value < 0.01, F = 7.21) on a black background. On white backgrounds, only a significant effect of treatment was reported for both Snow (p‐value < 0.01, F = 5.427) and Crest (p‐value < 0.001, F = 5.61).Overall, a combination of light and gel produces significantly higher tooth color and shade change over time, with the highest change seen for Snow products.Many patients use over‐the‐counter tooth bleaching products because they are more cost effective and easier to access than in‐office bleaching. However, these products may have adverse effects, such as increased sensitivity with repeated use, in addition to increased consumption of time and money. This project measured tooth shade between treatments which can help determine which product is most effective for at home use. [ABSTRACT FROM AUTHOR]

To explore the meshing mechanism of classic conic worm drive and provide a theoretical basis for creating other types of worm drive, a complete meshing theory on the proposed worm pair and its meshing performance are investigated. A new mathematical model containing a full set of geometric parameters on this drive is established using differential geometry. The formulae for calculating the reference point coordinates in different coordinate systems are attained, and then the blank size of the conical worm wheel is given. To build tooth surface boundaries, the meshing theory based on reference point is applied, which ensures the location of this point on the tooth surface. By solving multivariate nonlinear equation system in MATLAB environment, these conjugate regions and instantaneous contact lines are plotted within the axial section of the conic worm pair, at the same time, these values of sliding angle and induced principal curvature at meshing points are calculated. Finally, a numerical study is performed and the results verify that the conic worm pair has a relatively high tooth surface utilization ratio and favorable conditions for contact stress and lubrication, which is consistent with the practical application. [ABSTRACT FROM AUTHOR]

Purpose: The research paper comprehensively investigates the gear tooth deflection of standard thermoplastic gears with steel gear as the driver and driven companions. An accurate mapping of characteristic contact regions between the meshing gears was done, and the behaviour of the gear tooth in the premature and prolonged contact zones was studied. Design/methodology/approach: The study employs the finite element method to conduct a quasi-static 2D analysis of meshing gear teeth. The finite element model was created in AutoCAD and analysed using the ANSYS 19.1 simulation package. Findings: In the polymer-polymer gear combinations, premature and prolonged contact primarily occurs along the addendum radii of meshing gears, whereas a novel contact phenomenon was observed in the coast side for polymer-metal and metal-polymer combinations, exhibiting a path perpendicular to the standard drive side contact. As well, the deflection of the tooth alters the load distribution across the interlocking gears, leading to a decrement in the root stresses. Originality/value: The Lewis bending equation demonstrates that bending stresses depend solely on the applied load and the geometry of the tooth. It does not consider the effects of deflection. However, the computational results showed that the gear tooth deflection caused by different gear pair combinations also affects the bending stresses. The contact stresses observed in the polymer-polymer gear combination were observed to be within the material's proportional limit. However, when a steel gear is paired with a polymer gear, the contact stresses exceed the proportional limit due to coast side contact. [ABSTRACT FROM AUTHOR]

Aim: This study aims to compare and evaluate the fracture resistance of endodontically treated maxillary anterior teeth restored using new postplacement techniques. Methodology: Forty-five single-rooted maxillary anterior teeth (n = 15) were selected and decoronated at the cementoenamel junction. The working length was determined using a 15K file. Biomechanical preparation was done up to size 70 and the teeth were obturated. After 1 week, the root-filling material, gutta-percha, was removed, and postspace was prepared using a size 3 and 4 peeso reamer. The samples were divided into three groups (n = 15). Group I: Coltene Tenax fiber Post-reinforced with composite (anatomical post). Group II: Coltene Tenax fiber postreinforced with a leno-woven polyethylene; Ribbond fibers. Group III: Coltene Tenax fiber Post-luted with a dual cure cement. After postcementation, core buildup was done. Fracture resistance was measured using a universal testing machine. Results: Statistical analysis was done using one-way analysis of variance and Tukey's post hoc tests. A statistically significant difference was seen in the mean maximum load (N) between the groups. Group I showed the highest mean maximum load (N), followed by Group II and Group III. A significant P value (P = 0.025) was noted. Conclusion: Coltene Tenax fiber postreinforced with composite (anatomical post) showed the highest fracture resistance in endodontically treated maxillary anteriors. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effect of applying a matrix metalloproteinase (MMP) inhibitor on the fracture resistance of root-filled teeth restored with Everstick fiber-reinforced composite resin. Subjects and Methods: After the selection of 60 freshly extracted human mandibular first molar, root canal access and standard uniformly sized mesio-occluso-distal (MOD) cavities were made and the teeth were randomly assigned into three groups (n = 20 each): Group I, the MOD cavity was first lined with flowable composite resin and then restored with composite resin. In Group II, Everstick fiber was placed into the bed of flowable composite in buccal–pulpal–lingual direction before the composite restoration was placed. In Group III, after etching of the cavity, a 2% chlorhexidine MMP inhibitor was applied. Then, the MOD cavity was restored same as group II. A universal testing machine was employed to compressively load the teeth at a cross-head speed of 0.5 mm/min till fracture. The maximum fracture loads were recorded in Newtons (N) and data were analyzed with one-way ANOVA and post-hoc Tukey tests. Results: Group III exhibited significantly higher fracture resistance compared to all other groups (P < 0.001), whereas Group I demonstrated the lowest fracture resistance. Conclusion: The utilization of Everstick glass fiber, combined with MMP inhibitor treatment, yielded the greatest fracture resistance. Hence, this method may be prioritized over conventional restoration techniques for strengthening root canal-treated teeth with structurally compromised crowns. [ABSTRACT FROM AUTHOR]

Introduction: The absence of a barrier in an open root apex makes endodontic treatment challenging as root‐filling material can easily reach the surrounding tissue. The aim of the study was to compare the apical microleakage associated with mineral trioxide aggregate (MTA), biodentine, custom‐made gutta‐percha with MTA plus and custom‐made gutta‐percha with Adseal in immature permanent teeth by dye penetration method. Methods: Apical 2 mm of 60 single‐rooted mandibular premolar teeth was resected to create divergent open apices and 10 teeth each were filled with Biodentine plug, MTA plug, custom‐made gutta‐percha with MTA plus sealer and custom‐made gutta‐percha with Adseal sealer. Ten teeth each acted as positive and negative controls. All the samples were stored at 37°C at 100% humidity for 5 weeks and then immersed in 2% Rhodamine B dye for 24 h. Transverse sectioning was done apically at 1 mm and 3 mm to evaluate dye penetration under a fluorescence microscope using ImageJ software. Results: There was a significantly greater microleakage at 1 mm cross section compared to 3 mm (p < 0.0001). At 1 mm cross section, the apical microleakage was the highest for the MTA plug with a mean leakage percentage of 48.08 ± 16.38, a mean depth of leakage of 0.46 ± 0.10 mm and a mean area of leakage of 1.35 ± 0.74 mm2, compared to other groups, and the difference was statistically significant. However, at a 3 mm cross section, MTA plus sealer with gutta‐percha demonstrated the highest mean leakage percentage (25.01 ± 7.77) compared to other groups and the difference was statistically significant (p = 0.03). Conclusion: It can be concluded that the 3‐mm‐thick apical plug provided better sealing of the open apex compared to the 1 mm apical plug and there was no significant difference in microleakage among the Biodentine plug, MTA plug and Adseal sealer with gutta‐percha plug at 3 mm cross section. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusions Clinical Significance Immediate Tooth Replacement Therapy (ITRT) has become popular due to its ability to reduce treatment time and provide immediate esthetic results. However, long‐term challenges, such as mid‐facial recession and labial bone resorption, have been reported. Anatomic temporary cylinders (ATC), which allow for efficient fabrication of provisional transitional restorations in the esthetic zone, were designed to mimic the natural emergence profile and guide mucosal tissue healing. This study examines the effect of ATCs on the fabrication of provisional restorations compared to conventional non‐anatomic temporary cylinders (CTCs) in terms of peri‐implant mucosal preservation and stability in patients undergoing ITRT using the dual‐zone grafting technique.Parameters evaluated were peri‐implant mucosal tissue thickness (PIMTT), Pink Esthetic Score (PES), and radiographic outcomes, including labial plate dimension (LPD).The use of ATCs resulted in a statistically significant increase in PIMTT compared to CTCs, suggesting better preservation of peri‐implant mucosal architecture. Additionally, the ATC group exhibited a positive change in LPD, although this difference was not clinically significant.The findings indicate that ATCs may offer advantages in maintaining peri‐implant mucosal stability, contributing to the esthetic and functional outcomes of implant‐supported restorations. Further long‐term studies are needed to validate these preliminary results.The use of anatomic temporary cylinders (ATC) in immediate tooth replacement therapy (ITRT) demonstrated improved peri‐implant mucosal tissue thickness, suggesting enhanced maintenance of peri‐implant mucosal architecture. This can contribute to healthier and more esthetic outcomes while potentially reducing the risk of complications such as mid‐facial recession. [ABSTRACT FROM AUTHOR]

During the five-axis flank milling process, the uncut chip area varies continuously with the cutter motion, which leads to a challenging issue for the geometric construction of the instantaneous uncut chip thickness (IUCT). In this paper, a novel approach to calculate the IUCT effectively considering the cutter runout effect is proposed. The element motion of the cutter extracted from the cutter location file (CLF) is described with one linear variable and two angular variables, which are necessary factors in the IUCT calculation of five-axis milling. The geometry relationship between cutter motion and IUCT has been analyzed, and the parametric expression of IUCT in five-axis milling can be deduced to predict the cutting force. The explicit five-axis IUCT expression facilitates a more comprehensive understanding of the key parameters in the cutting process, which could be helpful in optimizing the processing parameters. Compared to the numerical method based on true tooth trajectories, the time consumption of the proposed method is reduced greatly in the simulation. The experiment of five-axis flank milling is carried out, and the result reveals that the presented method can be well applied to the practical milling process. We believe that the IUCT model in this paper will promote the simulation and optimization system in five-axis machining. [ABSTRACT FROM AUTHOR]

Heleocola piceanus, a new, relatively large metatherian from Upper Cretaceous ('Edmontonian') strata of the Williams Fork Formation in northwestern Colorado is described, based on a recently discovered jaw fragment (MWC 9744), in addition to three isolated teeth initially referred by other studies to Aquiladelphis incus and Glasbius piceanus. Although sharing several morphologic characters with the Lancian genus Glasbius, H. piceanus lower molars are considerably larger than those of Glasbius and differ from the latter in lacking a buccal cingulid, possessing carnassiform notches on the cristid obliqua and entocristid, and bearing an entoconulid on m3. To examine the relationship of Heleocola piceanus to other metatherians, H. piceanus was scored into a previously existing taxon-character matrix. Our phylogenetic analysis recovers H. piceanus as the sister taxon to Glasbius, which is consistent with our morphologic comparisons. H. piceanus represents the oldest member of the Glasbiidae. A regression equation for predicting body mass of dentally conservative metatherians that utilizes the length of m1 estimates the mass of H. piceanus at 855–1170 g, which is comparable in mass to today's muskrat (Ondatra zibethicus) and large relative to other Late Cretaceous pediomyoids. Based upon its molar morphology, specifically the low inflated cusps, low height differential between the trigonid and talonid, and near-bunodont morphology, H. piceanus is interpreted as an omnivore with a plant-dominated diet. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Methods Results Conclusions The objectives were to: (i) assess the accuracy of dental data for adults obtained from the Swedish Quality Register on Caries and Periodontitis (SKaPa); (ii) explore whether Latent Class Analysis (LCA) can identify groups of people based on caries data; and (iii) characterise the dental, medical and behavioural characteristics of people in the LCA‐derived classes.Caries data from the SKaPa register were compared with clinical data collected by five experienced dentists in a nested subgroup of the Malmö Offspring Study (MOS), namely the Malmö Offspring Dental Study (MODS) (n = 724) for validation. Dental data from SKaPa were then used to classify 61 984 adult participants of the Västerbotten Intervention Programme (VIP) into five classes using LCA and DMFS‐based quintile ranking, respectively. Dental status (including caries progression over 5 years), medical, anthropometric and behavioural characteristics were compared between the groups. Analyses were replicated in 2767 adults in the MOS.DMFS‐scores and number of teeth recorded within −2 to +2 years showed excellent agreement between the SKaPa and reference data with intra‐class correlations > 0.90. The five LCA classes differed in mean DMFS from 10.0 to 94.4. There were strong associations between LCA class and health, and health and behavioural measures respectively, including some associations that were not detected using DMFS‐ranked quintile groups. LCA class was associated with incremental change in DMFS, DFS, and number of teeth. The results in the MOS cohort were consistent with the results in the VIP cohort.Dental data for adults from the SKaPa registry were considered accurate within 2 years of recording. The LCA approach can classify participants into caries subtypes based on dental charting. These groups differ in health and behavioural characteristics and future caries increment. The LCA approach may capture some information that is missing from DMFS‐ranked quintile groups, but is also heavily influenced by total DMFS, meaning that applying LCA in cumulative, highly age‐determined diseases, such as caries, is a challenge. [ABSTRACT FROM AUTHOR]

In this study, inspired by human teeth, random hybrid carbon nanotubes (CNTs) and aramid‐pulp micro/nano‐fibers (AP) with different mixing ratios were experimentally interleaved into carbon fiber reinforced polymer (CFRP) panels to form a gradient interface for hierarchical enhancement and synthetic effects. Due to different out‐of‐plane movability or penetrability of the CNTs, AP, and resin, 3rd and 4th order bio‐inspired gradient interfaces between the carbon‐fiber plies were formed in situ. According to flexural testing, hybrid CNT/AP‐interleaved CFRP with a CNT of 3.6 gsm and an AP of 2.4 gsm showed an improvement of 47.35% in flexural strength. Furthermore, the synthetic effects of hybrid CNT/AP‐interleaving were investigated by analyzing the mer3its and demerits of the CNT‐ or AP‐interleaving methods. It was identified that the hybridization of multiple length‐scale fibers as interleaves can be used to produce more hierarchical enhancements and synthetic effects. The new insights into multi‐scale strengthening mechanisms were systematically revealed from the models of hierarchical fiber‐bridging. And the graded penetration mechanisms of multi‐scale fiber‐reinforced CFRP laminates were analyzed. Highlights: The in situ gradient interfaces form by Z‐direction penetration of CNT/AP.CNT/AP‐interleaving can form hierarchical enhancements and synthetic effects.Multi‐scale strengthening via fiber‐bridging and graded penetrations achieved.More fiber‐bridging occur at sub‐surface regions of the carbon‐fiber plies. [ABSTRACT FROM AUTHOR]

Objective: This study is aimed at detailing a technique for digitally fabricated fixed restoration for both immediate replacement after extraction and splinting of the adjacent mobile teeth. Clinical Considerations: Demand for a fixed restoration of the missing teeth in the mandibular anterior region is very common but sometimes problematic for dentists. It often happens that there is significant loosening of the remaining teeth adjacent to the missing tooth, which should be splinted. This case report describes a digitally fabricated fixed restoration for both replacing lost teeth and splinting periodontally compromised mobile teeth. With the CAD‐CAM technique, patients can receive the restoration immediately after the extraction. The digital design and fabrication of the restoration were elaborated using the restorative process of a patient with a mandibular anterior tooth to be extracted and multiple loose lower anterior teeth. The immediate restoration process and the pontic modification when the extraction socket had healed were also described. Conclusions: The digital process avoids the nudging of the loose tooth by the traditional impression technique, improves the accuracy of the restoration, and avoids undue stress on the loose tooth when the restoration is in place. In addition, this method allows the patient to obtain a fixed restoration immediately after extraction, and if damage occurs after the restoration has been cemented, such as fracture or debonding, a new restoration can be prepared before the patient's return visit. Clinical Significance: This minimally invasive restorative method achieved the fixation of loose teeth while restoring the missing teeth, but the success of the treatment needed long‐time observation. [ABSTRACT FROM AUTHOR]

Background: It is widely recognized that periodontal disease is associated with diabetes mellitus. Periodontal disease is accompanied by inflammation of the periodontal tissue, impaired masticatory function, and the presence of periodontopathic bacteria, all of which may affect glycemic control. However, the exact relationship between these factors and glycemic control has not yet been established. In this study, we aimed to investigate the relationship between periodontal disease-related factors and glycemic control in Japanese community-dwelling individuals. Methods: We conducted a cross-sectional study involving 671 participants aged 29–92 (65.3 ± 12.1) years, using data from the Nagasaki Islands Study. Participants underwent routine medical examinations, including body mass index (BMI) and hemoglobin A1c (HbA1c) levels. Information on the participants' demographics (age and sex) and whether they were on diabetes medications, had an exercise habit, consumed alcohol, engaged in late-night eating, had regular dental checkups, and smoked was obtained using a self-administered questionnaire. Dental examinations were performed to examine dentition status, probing pocket depth, clinical attachment level (CAL), and bleeding on probing. Functional tooth units (FTUs), defined as pairs of occluding posterior teeth, were used as an indicator of occlusal support area. Saliva samples were collected and levels of two species of periodontopathic bacteria (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans) were determined using real-time polymerase chain reaction. We analyzed the association between HbA1c levels and variables related to periodontal status, masticatory function, and salivary levels of periodontopathic bacteria. Results: Bivariate analysis showed that HbA1c levels were significantly associated with age, sex, exercise habit, BMI, diabetes medications, CAL, salivary P. gingivalis level, number of teeth, and three FTU subcategories. In the multiple regression analysis, age, BMI, diabetes medications, and total FTU score (i.e., including natural teeth, implant-supported artificial teeth, fixed prostheses, and removable dentures) remained associated with HbA1c levels (B = 0.23, 0.14, 0.52, and − 0.12; p < 0.001, p < 0.001, p < 0.001, and p = 0.008, respectively). Conclusions: In this community-based cross-sectional study, total FTU was significantly associated with HbA1c levels, independent of other risk factors. This suggests that reconstructed occlusal support areas, including dentures, are associated with glycemic control in the older population. [ABSTRACT FROM AUTHOR]

This study aimed to clinically evaluate the performance of non-preheated bulk fill resin composite in class II cavities versus one, five and ten-time preheating cycles at 68 °C. Eighty-four recruited participants were randomly allocated into four groups (21 patients per group). One posterior Bulk-fill proximal restoration was performed for each participant according to the preheating cycles where in group I; teeth were restored with non-heated resin composite, group II: One preheating cycle of composite syringe was performed prior restoration, and group III: five preheating cycles while for group IV: Ten preheating cycles were performed. These restorations were clinically evaluated at 6, 12, 18 and 24 months. Statistical analysis was performed using one way ANOVA, with set p-value < 0.05. The results revealed that there was perfect agreement between both observers and observations WK (95% CI) [0.908 (0.780:1.000)] and [0.940 (0.824:1.000)], respectively. All restorations showed acceptable clinical performance with alpha and bravo scores. No replacement was required for any restoration. No statistically significant differences were detected between the control and intervention groups across all parameters during the various evaluation stages. It could be concluded that the clinical performance of ten cycles of repeated preheated bulk fill resin composite was equivalent to that of non-preheating resin composites after 24 months follow-up period, with great improvement in manipulation. Preheating of resin composite could be performed up to ten cycles prior to placement without any clinical adverse consequences on the performance of the restoration. [ABSTRACT FROM AUTHOR]

Deciduous dentition of extinct mammals has traditionally received little attention based on its poor representation in the fossil record. However, several aspects related to this tooth locus could have important evolutionary significance (time of replacement, retention throughout life, and morphology). In this work, we described a new specimen from late Oligocene levels of Cabeza Blanca (Chubut Province, Argentina). This fossil corresponds to a maxillary fragment with a deciduous premolar (DP4) assigned herein to Cephalomys arcidens based on morphological characteristics, size, and comparisons with other late Oligocene-Early Miocene caviomorphs. It can be identified as a DP4 due to its mesiodistally longer than wide diameter, shallow flexi, complex tooth morphology, and its position in the maxillary fragment. This is the first description of the DP4 of a Cephalomyidae and the last unknown dental locus of Cephalomys arcidens. Now, C. arcidens is one of the better-known late Oligocene caviomorphs since it is recognised through the complete dentition, crania, and mandibles. In addition, this new information would be used to evaluate the importance of deciduous dentition in resolving phylogenetic relationships in the enigmatic cephalomyids in particular and in Caviomorpha in general. [ABSTRACT FROM AUTHOR]

Although rare-earth magnesium (Mg-RE) alloys are widely used in various industries, they show much poorer machinability for shaping into desired dimensions than conventional magnesium ones. The most critical issues associated with cutting Mg-RE alloys are high risk of chip ignition and short tool life dominating the chip removal process. The present paper aims to address the tool performances on the machinability of Mg-RE alloys under dry cutting. Four types of tools covering uncoated and diamond-coated ones were examined, and a special focus was devoted to explore the effects of various tool parameters on the milling responses of Mg-RE alloys as well as the underlying wear mechanisms. The experiments reveal that the cutting tools with larger rake, clearance, and helix angles can achieve high-quality milling of Mg-RE alloys at controllable cutting temperatures. The cutting parameters can be maintained at a certain level, such as the cutting speed of 120–240 m/min and the feed per tooth of 0.1–0.2 mm/z, to meet the requirements of safe milling of Mg-RE alloys without ignition risk. [ABSTRACT FROM AUTHOR]

During a crown generation procedure, dental technicians depend on commercial software to generate a margin line to define the design boundary for the crown. The margin line generation remains a non-reproducible, inconsistent, and challenging procedure. In this work, we propose to generate margin line points on prepared teeth meshes using adaptive point learning inspired by the AdaPointTr model. We extracted ground truth margin lines as point clouds from the prepared teeth and crown bottom meshes. The chamfer distance (CD) and infoCD loss functions were used for training a supervised deep learning model that outputs a margin line as a point cloud. To enhance the generation results, the deep learning model was trained based on three different resolutions of the target margin lines, which were used to back-propagate the losses. Five folds were trained and an ensemble model was constructed. The training and test sets contained 913 and 134 samples, respectively, covering all teeth positions. Intraoral scanning was used to collect all samples. Our post-processing involves removing outlier points based on local point density and principal component analysis (PCA) followed by a spline prediction. Comparing our final spline predictions with the ground truth margin line using CD, we achieved a median distance of 0.137 mm. The median Hausdorff distance was 0.242 mm. We also propose a novel confidence metric for uncertainty quantification of generated margin lines during deployment. The metric was defined based on the percentage of removed outliers during the post-processing stage. The proposed end-to-end framework helps dental professionals in generating and evaluating margin lines consistently. The findings underscore the potential of deep learning to revolutionize the detection and extraction of 3D landmarks, offering personalized and robust methods to meet the increasing demands for precision and efficiency in the medical field. [ABSTRACT FROM AUTHOR]

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Direct drive permanent magnet (PM) motors have become a very attractive choice for electric vehicles. Generally, PM motors are divided into PM synchronous motors (PMSMs) and PM flux‐modulated motors (PMFMMs). High torque density is the main requirement of direct drive motors, therefore, the structure of conventional PM motors is modified to boost the torque. Increasing the number of poles is a structural modification to achieve high torque density in PMSMs; however, a large number of poles affects motor characteristics such as power factor, flux weakening, losses, and efficiency. The other way to have high torque is to use PMFMMs, which have a high intrinsic torque density. This paper first compares the performance of PMSMs with different number of poles. Then the performance of PMFMMs and PMSMs are compared to show their differences. The performance of PMFMMs with different teeth modulators and magnetic gear ratios are predicted to show their effects upon its performance. The simulation results using finite elements method|finite element method (FEM) are presented, and finally, a PMFMM with 36 slots and 40 poles as case study is subjected to an experimental test and its results are compared with FEM. The cover image is based on the article Comparison of permanent magnet synchronous machine and permanent magnet flux‐modulated machine in direct drive considering number of rotor poles by Saeed Abareshi et al., https://doi.org/10.1049/elp2.12500. [ABSTRACT FROM AUTHOR]

Terrestrial carnivorans, with their diverse diets and unique adaptations such as the carnassial tooth, offer insights into the connections between functional traits and the climatic and environmental conditions they inhabit. They shed light on functional trait‐environment relationships at the highest trophic levels across a broad range of environmental conditions. In this study, we evaluate the relationship between relative blade length (RBL) of the lower carnassial tooth, a key dietary adaptation among terrestrial carnivorans for slicing and grinding food items, and climate. We propose RBL as an ecometric trait and test the hypothesis that community‐level RBL is correlated with climate and mediated by environmental effects on food availability. Our findings show that communities with higher mean and broader variance of RBL are typically located in warmer and wetter climates, suggesting a relationship between carnivoran dietary diversity and climate. Conversely, communities with a lower mean and narrower variance of RBL predominantly occupy cooler, drier places. This indicates that community‐level carnivoran dietary traits have the potential to serve as indicators of environmental conditions. Given the robust fossil record associated with carnivorans, we also show how RBL can be used as a proxy for reconstructing paleoclimates by examining trait change at seven sites in North America to estimate changes in temperature and precipitation over time in relation to changes in carnivoran community assembly. Understanding the nature of trait‐environment relationships can help us anticipate biological impacts of ongoing environmental change and the geographic regions at the greatest risk of ecological disruption. [ABSTRACT FROM AUTHOR]

We examine the distribution, habitat association, morphometrics, meristics, and reproductive attributes of Amblyraja radiata over much of its Canadian range, Grand Banks to Arctic waters. It is distributed widely on the shelf and upper slope between 30 and 1288 m, reaching highest density in 100–400 m and occupying most available temperatures, between −1.0 and 8.8 °C, but concentrating in 1.6–3.5 °C. The maximum (and average) size decreases with increasing latitude in a continuum from 102 cm (55 cm) in the south, to 45 cm (20 cm) in the north. The proportion of mature fish increases with depth (40% at 0–50 m to 80% at 1150–1200 m) and temperature (35% at <0 °C to 55% at 5+ °C). The size at maturity decreases south to north; size at onset of maturity in males—43 (south) to 19 (north) cm, in females—49 to 23 cm; length at 50% maturity in males—74 to 44 cm, in females—66 to 40 cm. A. radiata maturity is also reflected in the rapid increase in the size of secondary sexual characteristics. Some meristics were consistent over the entire study area (spines near the spiracles and shoulders) while others varied with latitude (teeth rows, midline spines, spines near the eyes, % dorsal fins joined, spines between dorsal fins) or by fish length/maturity; the tail length/total length as a proportion of total length decreased during Stage 1 then increased at onset of maturity. [ABSTRACT FROM AUTHOR]

The segmentation of teeth in 3D dental scans is difficult due to variations in teeth shapes, misalignments, occlusions, or the present dental appliances. Existing methods consistently adhere to geometric representations, omitting the perceptual aspects of the inputs. In addition, current works often lack evaluation on anatomically complex cases due to the unavailability of such datasets. We present a projection-based approach towards accurate teeth segmentation that operates in a detect-and-segment manner locally on each tooth in a multi-view fashion. Information is spatially correlated via recurrent units. We show that a projection-based framework can precisely segment teeth in cases with anatomical anomalies with negligible information loss. It outperforms point-based, edge-based, and Graph Cut-based geometric approaches, achieving an average weighted IoU score of 0.97122 ± 0.038 and a Hausdorff distance at 95 percentile of 0.49012 ± 0.571 mm. We also release Poseidon's Teeth 3D (Poseidon3D), a novel dataset of real orthodontic cases with various dental anomalies like teeth crowding and missing teeth. [ABSTRACT FROM AUTHOR]

This study is aimed to see how gender and whether tooth is placed on the right or left affected the length of the operation, edema, trismus, and discomfort after surgical extraction of an impacted mandibular third molar. This prospective study was conducted in the Inonu University. The study included 104 mandibular wisdom tooth with bone retention. There were 55 females and 49 males among the 104 patients, with 53 left and 51 right impacted mandibular third molar. The operations were performed by the same surgeon in the same operating room. The time between the incision and the suture was determined and recorded as the operation time for each procedure. Before surgery, on the 2nd postoperative day, and on the 7th postoperative day, the patients were compared in terms of facial swelling impacted mandibular third molar, discomfort, and trismus. IBM SPSS V23 was used to evaluate the data. The left impacted mandibular third molar extraction takes longer than the right impacted mandibular third molar extraction. Tooth 38, which have a longer operation time, are more prone to swelling, discomfort, and trismus. When tooths are extracted, right-handed surgeons cause less postoperative morbidity 48. We recommend that both right-handed, left-handed surgeons operate in clinics that conduct impacted tooth extractions. [ABSTRACT FROM AUTHOR]

Key Clinical Message: The principles of tissue preservation, minimally invasiveness and approaching different clinical situations biologically rather than surgically govern today's dentistry. Thus, different clinical scenarios require procedures that offer the dentist and the patient the possibility to choose the more invasive treatment options later in life. Subsequently, the case reported refers to a minimally invasive technique that treats single tooth edentulism using single partial retainer FDPs fabricated from monolithic zirconia. This approach is conservative, biocompatible, aesthetic, strong, rapidly obtained through CAD/CAM techniques and cost‐effective. [ABSTRACT FROM AUTHOR]

Aim: The aim of this analysis was to compare a clinical periodontal prognostic system and a developed and externally validated artificial intelligence (AI)‐based model for the prediction of tooth loss in periodontitis patients under supportive periodontal care (SPC) for 10 years. Materials and Methods: Clinical and radiographic parameters were analysed to assign tooth prognosis with a tooth prognostic system (TPS) by two calibrated examiners from different clinical centres (London and Pittsburgh). The prediction model was developed on the London dataset. A logistic regression model (LR) and a neural network model (NN) were developed to analyse the data. These models were externally validated on the Pittsburgh dataset. The primary outcome was 10‐year tooth loss in teeth assigned with 'unfavourable' prognosis. Results: A total of 1626 teeth in 69 patients were included in the London cohort (development cohort), while 2792 teeth in 116 patients were included in the Pittsburgh cohort (external validated dataset). While the TPS in the validation cohort exhibited high specificity (99.96%), moderate positive predictive value (PPV = 50.0%) and very low sensitivity (0.85%), the AI‐based model showed moderate specificity (NN = 52.26%, LR = 67.59%), high sensitivity (NN = 98.29%, LR = 91.45%), and high PPV (NN = 89.1%, LR = 88.6%). Conclusions: AI‐based models showed comparable results with the clinical prediction model, with a better performance in specific prognostic risk categories, confirming AI prediction model as a promising tool for the prediction of tooth loss. [ABSTRACT FROM AUTHOR]

This study establishes an empirical model for a four-flute cylindrical helical end mill, utilizing orthogonal cutting tests on a Ti-6Al-4V block as the machining workpiece. The reliability of the model was confirmed through a titanium alloy side milling experiment. Results demonstrate that the empirical index model for predicting the main cutting force error falls within the range of 4.19 %–10.0 %, providing an effective tool for cutting force prediction. The specific influence distribution trends of cutting parameters, including milling speed, feed per tooth, and depth of cut, on the cutting force through two-step milling of profile walled surface of titanium alloy were analyzed. The results reveal that the milling force in the first step exhibits a discernible upward trend with the increase of feed per tooth and radial depth of cut. Among the cutting parameters employed in the first step, the cutting speed exerts the most significant influence on the cutting force in the second step. [ABSTRACT FROM AUTHOR]

To address the issue of gear transmission error caused by noncircular gear backlash, enhancing the contact ratio of noncircular gears can prolong the meshing time of gear pairs, enhance the effective meshing line length, and consequently, reduce the transmission errors caused by gear backlash. Therefore, this study proposes a design method for high-contact-ratio variable-involute and incomplete variable-cycloid composite tooth profile (VIIVC-CTF). This method enhances the contact ratio of a small curvature radius pitch curve noncircular gear; derives a mathematical model for high-contact-ratio VIIVC-CTF; and analyzes the relationships of pitch curve ratio, rolling radius, and elliptical eccentricity with tooth profile shape, contact ratio, pressure angle, and curvature radius of high-contact-ratio composite tooth profile. Using a small curvature radius pitch curve noncircular gear as an example, a noncircular gear with high-contact-ratio composite tooth profile was manufactured. Tests were conducted to measure the tooth backlash and transmission ratio of the noncircular gear. Testing results showed that the tooth backlash of the high-contact-ratio composite tooth profile was smaller than that of the standard-involute tooth profile. The experimental, theoretical, and simulation values of the noncircular gear transmission ratio were consistent, validating the rationality of the design method for high-contact-ratio VIIVC-CTF. [ABSTRACT FROM AUTHOR]

Identifying the boundary between the tooth and the resin-based composite (RBC) is difficult when replacing restorations. Ultraviolet (UV) light has been reported to assist the viewer by causing the RBC to fluoresce. Using a laboratory-grade fiberoptic spectrometer, 46 RBCs were exposed to UV light from the Woodpecker O-Star curing light. The opalescence and fluorescence were measured relative to a human tooth that contained just dentin and a tooth that contained both enamel and dentin. After these quantitative measurements, 10 RBCs with large differences in light emittance were compared qualitatively to assess their brightness when exposed to UV light compared to the dentin specimen and the specimen containing both enamel and dentin. It was found that, when exposed to UV light, some of the RBCs were less bright compared to the two samples of teeth used for comparison, but most were brighter; some were up to six times brighter. The filler appears to affect the opalescence peaks, while the resin appears to affect the fluorescence peaks. It was concluded that because RBCs emit very different levels of opalescence and fluorescence, UV light from the Woodpecker O-Star cannot be relied upon to detect all brands of RBC on the tooth. The opalescence and fluorescence can also be used to detect changes in the formulation of the RBC. [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]