Physical properties and wear behavior of CAD/CAM resin composite blocks containing S-PRG filler for restoring primary molar teeth

Objectives: This study aimed to develop computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite blocks (RCBs) containing surface pre-reacted glass-ionomer (S-PRG) filler for primary molar teeth and evaluate their physical properties and wear resistance. Methods: Experimental CAD/CAM RCBs containing S-PRG filler for primary molar teeth (EB), a commercial CAD/CAM RCB (HC), two resin composites for primary teeth (BKP and BKZ) and one for permanent teeth (BⅡ) were used. Hardness tests, three-point bending tests, fracture toughness tests, and water absorption tests were conducted. Wear tests were conducted for these materials and stainless steel crowns (SSCs). Results: The Vickers hardness of EB was lower than that of HC (p 0.05). After 1 week of water immersion, EB and HC showed greater flexural strength than the other materials (p < 0.05). EB showed greater fracture toughness than the other materials (p < 0.05). The water absorption of EB was lower than that of HC, BKZ, and BKP (p < 0.05), and greater than that of BⅡ (p < 0.05). Antagonist wear was significantly smaller in EB than in HC and BⅡ (p < 0.05), and significantly greater than in BKZ (p < 0.05). Antagonist wear could not be measured in SSC because of excessive wear that was out of range of the surface roughness tester. Significance: The CAD/CAM RCBs containing S-PRG filler for primary molar teeth developed in this study demonstrated adequate physical properties and wear performance, suggesting that they are suitable for restoration of primary molar teeth and could function in place of SSCs.Nakase Y., Yamaguchi S., Okawa R., et al. Physical properties and wear behavior of CAD/CAM resin composite blocks containing S-PRG filler for restoring primary molar teeth. Dental Materials 38, 158 (2022); https://doi.org/10.1016/j.dental.2021.11.001

In vitro analysis of durability of S-PRG filler-containing composite crowns for primary molar restoration

Objective: To evaluate the reliability, maximum principal stress, shear stress, and crack initiation of a computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite (RC) incorporating surface pre-reacted glass (S-PRG) filler for primary molar teeth. Methods: Mandibular primary molar crowns fabricated by experimental (EB) or commercially available CAD/CAM RCs (HC) were prepared and cemented to a resinous abutment tooth using an adhesive resin cement (Cem) or a conventional glass-ionomer cement (CX). These specimens were subjected to a single compressive test (n = 5/each) and the step-stress accelerated life testing (SSALT) (n = 12/each). Data was evaluated using Weibull analyses and reliability was calculated. Afterwards, the maximum principal stress and crack initiation point of each crown was analyzed by finite element analysis. To evaluate bonding of EB and HC to dentin, microtensile bond strength (μTBS) testing was conducted using primary molar teeth (n = 10/each). Results: There was no significant difference between the fracture loads of EB and HC for either cement (p > 0.05). The fracture loads of EB-CX and HC-CX were significantly lower than EB-Cem and HC-Cem (p 0.05). Significance: The crowns fabricated with the experimental CAD/CAM RC incorporating S-PRG filler yielded greater fracture loads and reliability than the crowns manufactured with commercially available CAD/CAM RC regardless of the luting materials. These findings suggest that the experimental CAD/CAM RC crown may be clinically useful for the restoration of primary molars.Nakase Y., Yamaguchi S., Jalkh E.B.B., et al. In vitro analysis of durability of S-PRG filler-containing composite crowns for primary molar restoration. Dental Materials 39, 640 (2023); https://doi.org/10.1016/j.dental.2023.04.006

Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector

The rejection of forward jets originating from additional proton–proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range |η| &gt; 2.5. This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5 &lt; |η| &lt; 4.5 is estimated in simulated events with an average of 22 interactions per bunch-crossing. It increases with jet transverse momentum and, for jets with transverse momentum between 20 and 50 GeV, it ranges between 49% and 67% with an efficiency of 85% for selecting hard-scatter jets. A case study is performed in Higgs boson production via the vector-boson fusion process, showing that these techniques mitigate the background growth due to additional proton–proton interactions, thus enhancing the reach for such signatures

Dental Manifestations and Oral Management of X-Linked Hypophosphatemia

X-linked hypophosphatemia (XLH) is the most common genetic form of rickets and osteomalacia and is characterized by growth retardation, deformities of the lower limbs, and bone and muscular pain. Spontaneous dental abscesses caused by endodontic infections due to dentin dysplasia are well-known dental manifestations. When dentin affected by microcracks or attrition of the enamel is exposed to oral fluids, oral bacteria are able to invade the hypomineralized dentin and pulp space, leading to pulp necrosis, followed by the formation of a periapical gingival abscess. Without appropriate dental management, this dental manifestation results in early loss of teeth and deterioration in the patient’s quality of life. Early specific dental intervention and oral management in collaboration with medical personnel are strongly recommended for XLH patients. Importantly, dental manifestations sometimes appear before the diagnosis of XLH. Dentists should be alert for this first sign of XLH and refer affected children to a pediatrician for early diagnosis. A humanized monoclonal antibody for FGF23 (burosumab) is a promising new treatment for XLH; however, the effects on the dental manifestations remain to be elucidated. The establishment of fundamental dental therapy to solve dental problems is still underway and is eagerly anticipated

Dental Manifestations and Oral Management of X-Linked Hypophosphatemia

X-linked hypophosphatemia (XLH) is the most common genetic form of rickets and osteomalacia and is characterized by growth retardation, deformities of the lower limbs, and bone and muscular pain. Spontaneous dental abscesses caused by endodontic infections due to dentin dysplasia are well-known dental manifestations. When dentin affected by microcracks or attrition of the enamel is exposed to oral fluids, oral bacteria are able to invade the hypomineralized dentin and pulp space, leading to pulp necrosis, followed by the formation of a periapical gingival abscess. Without appropriate dental management, this dental manifestation results in early loss of teeth and deterioration in the patient&rsquo;s quality of life. Early specific dental intervention and oral management in collaboration with medical personnel are strongly recommended for XLH patients. Importantly, dental manifestations sometimes appear before the diagnosis of XLH. Dentists should be alert for this first sign of XLH and refer affected children to a pediatrician for early diagnosis. A humanized monoclonal antibody for FGF23 (burosumab) is a promising new treatment for XLH; however, the effects on the dental manifestations remain to be elucidated. The establishment of fundamental dental therapy to solve dental problems is still underway and is eagerly anticipated

Different Dental Manifestations in Sisters with the Same ALPL Gene Mutation: A Report of Two Cases

Hypophosphatasia (HPP) is an inherited disease caused by mutation of the alkaline phosphatase (ALPL) gene in an autosomal dominant or an autosomal recessive manner. The main symptoms of HPP are bone hypomineralization and early exfoliation of the primary teeth. Some of the mutations identified in autosomal dominant families are reported to have dominant negative effects. In addition, the penetrance can vary among patients with the same variant even within the same family, resulting in various phenotypes of systemic symptoms. However, differences in dental symptoms between patients with HPP and carriers with the same ALPL variant have not been reported. Herein, we report on two sisters who had the same heterozygous ALPL variant with dominant negative effects. The older sister had bone and dental symptoms and was diagnosed with childhood HPP. In contrast, the younger sister was a carrier with no bone and dental symptoms. It can be inferred that this phenomenon was caused by the difference in penetrance. This case revealed that carriers with the ALPL mutation may have no dental symptoms characteristic of HPP. Because HPP is sometimes progressive, it is very important to carefully monitor carriers to detect the possible onset of dental and systemic symptoms

Large-Scale Survey of Missing Deciduous Anterior Teeth on Medical Examination at the Age of 3.5 Years

Tooth anomalies in childhood may negatively affect the healthy development of the dentition and occlusion; hence, it is important to examine the actual oral condition at an early stage. The present study was performed to understand the state of missing deciduous anterior teeth in children aged 3.5 years who underwent dental checkups in Matsubara City. In total, 3508 children received oral examinations, and items such as erupted deciduous teeth and teeth anomalies were recorded. Among these children, those with missing anterior deciduous teeth were selected, and their details were analyzed. In the 216 children, there were 266 missing anterior deciduous teeth. Congenitally missing anterior deciduous teeth were observed in 80 children, and fused teeth were observed in 128 children. The missing teeth were predominantly located in the mandible and occurred more frequently on the right side. The most common reason for acquired missing teeth was trauma, and no cases of spontaneous loss due to systemic disease were found in this study. Screening for various tooth anomalies is expected to play an important role in cultivating a better understanding of the oral cavity of children, developing healthy dentitions, and contributing to the early detection of some systemic diseases

Osteomyelitis Possibly Caused by Exfoliation of Primary Teeth in a Patient with Osteopetrosis

Osteopetrosis is a rare inherited skeletal disease characterized by increased density in the bones and can be detected by radiographs. Sclerosis makes the jaw bones extremely susceptible to infections, osteomyelitis, and fractures. Here, we report a case of osteomyelitis possibly caused by spontaneous exfoliation of primary teeth in a patient with osteopetrosis. A 2 years and 9 months (2Y9M)-old boy with osteopetrosis was referred to our clinic for oral management. Only four primary central incisors had erupted, and they all exhibited hypoplasia. The mandibular right central primary incisor suddenly became exfoliated at 4 years and 1 month. The mandibular right lateral primary incisor also became exfoliated at 4 years and 3 months, soon after eruption, and the mandibular left central primary incisor became exfoliated at 4 years and 5 months. Subsequently, we confirmed the eruption of calcified tissue at 4 years and 9 months in the location where the mandibular right lateral primary incisor had become exfoliated. The patient was admitted to the pediatrics clinic for mandibular cellulitis at 5 years and 2 months, then referred to our clinic for the management of osteomyelitis. The patient&rsquo;s acute inflammation was reduced by repeated irrigation and the administration of antibiotics; the inflammation gradually became chronic. When treating patients with osteopetrosis, dentists and oral surgeons should prioritize infection control in the jaw, periodic assessment of dental eruption, and the maintenance of oral hygiene

A Case of X-Linked Hypophosphatemic Rickets with Dentin Dysplasia in Mandibular Third Molars

X-linked hypophosphatemic rickets (XLH) is a disease characterized by impaired bone mineralization, and its dental features include gingival abscesses and large pulp spaces due to dentin dysplasia. A 20-year-old woman with XLH was referred to oral surgery for extraction of mandibular third molars. She was diagnosed with XLH at approximately 1 year of age and was treated thereafter. There was no history of gingival abscesses, and panoramic radiographic and computed tomographic examinations revealed no evidence of dentin dysplasia. However, histopathological examination of the extracted teeth showed dentin dysplasia, including interglobular dentin. In this XLH patient, dentin dysplasia was revealed histologically even though no obvious abnormality was found on visual and radiographic examinations. These findings suggest that in patients with XLH, oral management must take dentin dysplasia of the permanent teeth into consideration even if the patient’s general condition is well controlled with conventional therapy

Automatic dental age calculation from panoramic radiographs using deep learning: a two-stage approach with object detection and image classification

Abstract Background Dental age is crucial for treatment planning in pediatric and orthodontic dentistry. Dental age calculation methods can be categorized into morphological, biochemical, and radiological methods. Radiological methods are commonly used because they are non-invasive and reproducible. When radiographs are available, dental age can be calculated by evaluating the developmental stage of permanent teeth and converting it into an estimated age using a table, or by measuring the length between some landmarks such as the tooth, root, or pulp, and substituting them into regression formulas. However, these methods heavily depend on manual time-consuming processes. In this study, we proposed a novel and completely automatic dental age calculation method using panoramic radiographs and deep learning techniques. Methods Overall, 8,023 panoramic radiographs were used as training data for Scaled-YOLOv4 to detect dental germs and mean average precision were evaluated. In total, 18,485 single-root and 16,313 multi-root dental germ images were used as training data for EfficientNetV2 M to classify the developmental stages of detected dental germs and Top-3 accuracy was evaluated since the adjacent stages of the dental germ looks similar and the many variations of the morphological structure can be observed between developmental stages. Scaled-YOLOv4 and EfficientNetV2 M were trained using cross-validation. We evaluated a single selection, a weighted average, and an expected value to convert the probability of developmental stage classification to dental age. One hundred and fifty-seven panoramic radiographs were used to compare automatic and manual human experts’ dental age calculations. Results Dental germ detection was achieved with a mean average precision of 98.26% and dental germ classifiers for single and multi-root were achieved with a Top-3 accuracy of 98.46% and 98.36%, respectively. The mean absolute errors between the automatic and manual dental age calculations using single selection, weighted average, and expected value were 0.274, 0.261, and 0.396, respectively. The weighted average was better than the other methods and was accurate by less than one developmental stage error. Conclusion Our study demonstrates the feasibility of automatic dental age calculation using panoramic radiographs and a two-stage deep learning approach with a clinically acceptable level of accuracy