The prevalence and characteristics of external cervical resorption based on cone-beam computed tomographic imaging: a cross-sectional study

Ferreira Matheus Diniz,Barros-Costa Matheus,Costa Felipe Ferreira,Freitas Deborah Queiroz 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.4

Objectives This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans. Materials and Methods CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ2 test. Intra-observer agreement was analyzed with the kappa test (α = 0.05). Results In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent. Conclusions The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry. Objectives This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans. Materials and Methods CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ2 test. Intra-observer agreement was analyzed with the kappa test (α = 0.05). Results In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent. Conclusions The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry.

Potential impact of metal crowns at varying distances from a carious lesion on its detection on cone-beam computed tomography scans with several protocols

Barros-Costa Matheus,Nascimento Eduarda Helena Leandro,Correia-Dantas Iago Filipe,Oliveira Matheus L.,Freitas Deborah Queiroz 대한영상치의학회 2024 Imaging Science in Dentistry Vol.54 No.1

Purpose: This study evaluated the impact of artifacts generated by metal crowns on the detection of proximal caries lesions in teeth at various distances using cone-beam computed tomography (CBCT). Additionally, the diagnostic impacts of tube current and metal artifact reduction (MAR) were investigated. Materials and Methods: Thirty teeth were arranged within 10 phantoms, each containing 1 first premolar, 1 second premolar, and 1 second molar. A sound first molar (for the control group) or a tooth with a metal crown was placed. Of the 60 proximal surfaces evaluated, 15 were sound and 45 exhibited enamel caries. CBCT scans were acquired using an OP300 Maxio unit (Instrumentarium, Tuusula, Finland), while varying the tube current (4, 8, or 12.5 mA) and enabling or disabling MAR. Five observers assessed mesial and distal surfaces using a 5-point scale. Multi-way analysis of variance was employed for data comparison, with P<0.05 indicating statistical significance. Results: The area under the curve (AUC) varied from 0.40 to 0.60 (sensitivity: 0.28-0.45, specificity: 0.44-0.80). The diagnostic accuracy was not significantly affected by the presence of a metal crown, milliamperage, or MAR (P>0.05). However, the overall AUC and specificity were significantly lower for surfaces near a crown (P<0.05). Conclusion: CBCT-based caries detection was not influenced by the presence of a metal crown, variations in milliamperage, or MAR activation. However, the diagnostic accuracy was low and was further diminished for surfaces near a crown. Consequently, CBCT is not recommended for the detection of incipient caries lesions.

Catalytic Properties of Lipases Immobilized onto Ultrasound-treated Chitosan Supports

Matheus Dorneles de Mello,Deborah Cordeiro,Lilian Terezinha Costa,Cristian Follmer 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

Ultrasound sonication has been utilized toproduce fragmentation of chitosan polymer and hence increasethe chitosan surface area, making it more accessible tointeractions with proteins. In this context, we haveinvestigated the catalytic properties of lipases from differentsources immobilized onto ultrasound-treated chitosan (ChiS)pre-activated with glutaraldehyde (ChiS-G). Atomic forcemicroscopy indicated that ChiS-G displays a more cohesiveframe without the presence of sheared/fragmented structureswhen compared with ChiS, which might be attributed tothe cross-linking of the polysaccharide chains. Theimmobilization efficiency onto ChiS-G and ChiS wereremarkably higher than using conventional beads. Incomparison with the free enzymes, lipases immobilizedonto ChiS show a slight increase of apparent Km anddecrease of apparent Vmax. On the other hand, immobilizationonto ChiS-G resulted in an increase of Vmax, even though aslight increase of Km was also observed. These datasuggest that the activation of chitosan with glutaraldehydehas beneficial effects on the activity of the immobilizedlipases. In addition, the immobilization of the lipases ontoChiS-G displayed the best reusability results: enzymesretained more than 50% of its initial activity after fourreuses, which might be attributed to the covalent attachmentof enzyme to activated chitosan. Overall, our findingsdemonstrate that the immobilization of lipases ontoultrasound-treated chitosan supports is an effective andlow-cost procedure for the generation of active immobilizedlipase systems, being an interesting alternative to conventionalchitosan beads.

Improved LMI Conditions for Unknown Input Observer Design of Discrete-time LPV Systems

Matheus Senna de Oliveira,Renan Lima Pereira 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.10

This paper presents a novel unknown input observer (UIO) design for discrete-time linear parametervarying (LPV) systems. One feature of the proposed approach is the ability of handling LPV systems with variation in both states and outputs matrices. The design problem has been formulated using a less conservative discrete-time stability condition which allows to obtain proportional UIO and proportional-integral UIO structures. Existence conditions for both structures are provided. These poly-quadratic conditions rely on the use of parameter-dependentLyapunov functions defined in terms of Linear Matrix Inequalities. Furthermore, an extended formulation using the H∞ performance index is also derived. Finally, the effectiveness of the proposed design method is illustrated through numerical examples.

Chlorhexidine gel associated with papain in pulp tissue dissolution

Matheus Melo Pithon,Gabriel Couto De Oliveira,Caio Souza Ferraz,Carlos Vieira Andrade Júnior 대한치과보존학회 2013 Restorative Dentistry & Endodontics Vol.38 No.4

Objectives This study aimed to evaluate the capacity of 2% chlorhexidine gel associated with 8% papain gel in comparison with 5.25% sodium hypochlorite in bovine pulp tissue dissolution. Materials and Methods Ninety bovine pulps of standardized sizes were used and fragmented into 5-mm sizes. The fragments were removed from the root middle third region. They were divided into 6 experimental groups (n = 15), 1) 8% papain; 2) 2% chlorhexidine; 3) 2% chlorhexidine associated with 8% papain; 4) 0.9% saline solution; 5) 2.5% sodium hypochlorite; and 6) 5.25% sodium hypochlorite. The pulp fragments were weighed and put into immobile test tubes for dissolution for time intervals of 30, 60, 90, and 120 min. Results The 5.25% sodium hypochlorite had greater dissolution potential than the pure papain, and when associated with chlorhexidine, both promoted greater dissolution than did the saline solution and 2% chlorhexidine groups (p < 0.05). The 2.5% sodium hypochlorite promoted dissolution to a lesser extent than the groups with papain within a period of 30 min (p < 0.05), but, was comparable to the saline solution and chlorhexidine. After 120 min, the 2.5% and 5.25% sodium hypochlorite promoted dissolution of 100% of the pulp fragments, and papain, 61%, while chlorhexidine associated with papain and chlorhexidine alone dissolved only 55% and 3%, respectively. Conclusions The 8% papain in gel, both alone and in association with chlorhexidine, was able to dissolve bovine pulp tissue, but to a lesser extent than did 5.25% sodium hypochlorite. Objectives This study aimed to evaluate the capacity of 2% chlorhexidine gel associated with 8% papain gel in comparison with 5.25% sodium hypochlorite in bovine pulp tissue dissolution. Materials and Methods Ninety bovine pulps of standardized sizes were used and fragmented into 5-mm sizes. The fragments were removed from the root middle third region. They were divided into 6 experimental groups (n = 15), 1) 8% papain; 2) 2% chlorhexidine; 3) 2% chlorhexidine associated with 8% papain; 4) 0.9% saline solution; 5) 2.5% sodium hypochlorite; and 6) 5.25% sodium hypochlorite. The pulp fragments were weighed and put into immobile test tubes for dissolution for time intervals of 30, 60, 90, and 120 min. Results The 5.25% sodium hypochlorite had greater dissolution potential than the pure papain, and when associated with chlorhexidine, both promoted greater dissolution than did the saline solution and 2% chlorhexidine groups (p < 0.05). The 2.5% sodium hypochlorite promoted dissolution to a lesser extent than the groups with papain within a period of 30 min (p < 0.05), but, was comparable to the saline solution and chlorhexidine. After 120 min, the 2.5% and 5.25% sodium hypochlorite promoted dissolution of 100% of the pulp fragments, and papain, 61%, while chlorhexidine associated with papain and chlorhexidine alone dissolved only 55% and 3%, respectively. Conclusions The 8% papain in gel, both alone and in association with chlorhexidine, was able to dissolve bovine pulp tissue, but to a lesser extent than did 5.25% sodium hypochlorite.

Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners

Matheus L. Oliveira,Guilherme M. Tosoni,David H. Lindsey,Kristopher Mendoza,Sotirios Tetradis,Sanjay M. Mallya 대한영상치의학회 2014 Imaging Science in Dentistry Vol.44 No.4

Purpose: To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods: Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results: The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion: There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

Influence of Electrolytic and Crevice Corrosion on Mechanical Resistance of Porcelain Insulators

Matheus Rabelo,Simpy Sanyal,Taeyong Kim,Ju-Am Son,In-Hyuk Choi,Junsin Yi 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7

Porcelain insulators are widely used in transmission lines; however, their durability and considerable overall maintenance cost have become problems over the years. In this work, porcelain insulators were collected from various locations in South Korea and classified according to their length of service. Mechanical and electrical load tests were performed, and the failure load and damaged region were recorded for each specimen. The fast degradation of the pin in porcelain insulators exceeding 50 years in operation was notable because there was no pin breakage among the samples in service for less than 50 years. Moreover, the failure of 73.68% of all porcelain insulators in service for 54 years occurred in the pin. The average failure load of these samples was 14% lower than that of samples in use for 45 years. To confirm the pin’s deterioration mechanism over time, a mechanical analysis of the reduction in the pin cross-section was performed using the finite element analysis method. Accordingly, a novel degradation mechanism is proposed in this study. Previous studies that focused on the critical areas of the porcelain insulator found that the exposed pin side was easily damaged by the external load. The current findings revealing an unfamiliar porcelain deterioration mechanism may aid in the formulation of a better design to mitigate the problems described above.

An Investigation of Different Cooling Techniques in Photovoltaic (PV) Modules and Their Impact on Module’s Efficiency and Durability

Matheus Rabelo Rabelo,Junsin Yi,Hasnain Yousuf,Xinyi Fan,Jaeun Kim,Eun-Chel Cho 한국신재생에너지학회 2022 한국신재생에너지학회 학술대회논문집 Vol.2022 No.4

Primary somatosensory cortex and periaqueductal gray functional connectivity as a marker of the dysfunction of the descending pain modulatory system in fibromyalgia

Matheus Soldatelli,Álvaro de Oliveira Franco,Felipe Picon,Juliana Ávila Duarte,Ricardo Scherer,Janete Bandeira,Maxciel Zortea,Iraci Lucena da Silva Torres,Felipe Fregni,Wolnei Caumo 대한통증학회 2023 The Korean Journal of Pain Vol.36 No.1

Background: Resting-state functional connectivity (rs-FC) may aid in understanding the link between painmodulating brain regions and the descending pain modulatory system (DPMS) in fibromyalgia (FM). This study investigated whether the differences in rs-FC of the primary somatosensory cortex in responders and non-responders to the conditioned pain modulation test (CPM-test) are related to pain, sleep quality, central sensitization, and the impact of FM on quality of life. Methods: This cross-sectional study included 33 females with FM. rs-FC was assessed by functional magnetic resonance imaging. Change in the numerical pain scale during the CPM-test assessed the DPMS function. Subjects were classified either as non-responders (i.e., DPMS dysfunction, n = 13) or responders (n = 20) to CPM-test. A generalized linear model (GLM) and a receiver operating characteristic (ROC) curve analysis were performed to check the accuracy of the rs-FC to differentiate each group. Results: Non-responders showed a decreased rs-FC between the left somatosensory cortex (S1) and the periaqueductal gray (PAG) (P < 0.001). The GLM analysis revealed that the S1-PAG rs-FC in the left-brain hemisphere was positively correlated with a central sensitization symptom and negatively correlated with sleep quality and pain scores. ROC curve analysis showed that left S1-PAG rs-FC offers a sensitivity and specificity of 85% or higher (area under the curve, 0.78, 95% confidence interval, 0.63–0.94) to discriminate who does/does not respond to the CPM-test. Conclusions: These results support using the rs-FC patterns in the left S1-PAG as a marker for predicting CPM-test response, which may aid in treatment individualization in FM patients.

In Vitro Trypanocidal Activity of Macela (Achyrocline satureioides) Extracts against Trypanosoma evansi

Matheus D. Baldissera,Camila B. Oliveira,Carine E. P. Zimmermann,Aline A. Boligon,Margareth Linde Athayde,Leandro P. Bolzan,Rodrigo de A. Vaucher,Janio M. Santurio,Michele R. Sagrillo,Aleksandro Schaf 대한기생충학열대의학회 2014 The Korean Journal of Parasitology Vol.52 No.3