Inyección de composite fluido técnica analógica vs técnica digital en el tratamiento de desgaste dental: reporte de caso / Fluid composite injection analog vs digital technique in the treatment of dental wear: case report

El avance de la tecnología permite realizar cambios en la rehabilitación y estética, reduce los tiempos de trabajo y disminuye los riesgos que se presentan al momento de utilizar materiales convencionales para la toma de impresiones. Existen dos técnicas que se pueden emplear, la analógica y la digital; la primera presenta mayores riesgos que el operador no puede controlar, así como tiempos más prolongados. Este reporte describe la rehabilitación bucal en dos pacientes con desgaste dental, se optó por usar ambas técnicas, la analógica y la digital, como tratamiento; en la primera se empleó el encerado convencional y en la segunda el software Exocad para el encerado digital. Finalmente en ambos casos se aplicó (AU)

The advance of technology has allowed changes in rehabilitation and esthetics, providing shorter working times and reducing the risks that occur when using conventional materials for taking impressions. There are two techniques that can be used, analog and digital, the first one presents greater risks that the operator cannot control, as well as more time. This report describes the oral rehabilitation in patients with dental wear. The treatment was carried out using the analogical and digital techniques, the former using conventional waxing and the latter using Exocad software for the digital waxing; finally, in both cases the injection technique with high-load Flow resin was used (AU)

Restablecimiento de guía anterior con restauraciones adhesivas / Reestablishing of anterior guidance with adhesive restorations

La estética ha llegado a formar una parte muy importante en la odontología actual. Sin embargo, no debemos sobreponer las necesidades estéticas sobre las necesidades funcionales. La pérdida de estructura dental asociada a bruxismo puede ser considerada patológica cuando compromete la guía anterior, la cual es la influencia en los movimientos mandibulares que proveen las superficies contactantes de los dientes maxilares anteriores con los mandibulares anteriores y evita contactos excéntricos dañinos en los dientes posteriores. El objetivo de este reporte de caso es presentar una alternativa conservadora para restablecer tanto la estética como la funcionalidad de una paciente de 34 años de edad que acudió a la Clínica de Prostodoncia de la Universidad Autónoma de Guadalajara en busca de rehabilitación estética de dientes anteriores. Una vez realizada su evaluación inicial se llegó al diagnóstico de pérdida de guía anterior por desgaste patológico asociado a bruxismo. El tratamiento incluyó tratamientos de conductos, remoción de caries y restauraciones mal ajustadas, coronas y carillas para restablecer la guía anterior. Se cumplieron con las expectativas estéticas que tenía la paciente al igual que con las necesidades funcionales que fueron objetivo desde el inicio, logrando un restablecimiento de la guía anterior de manera conservadora (AU)

Esthetics has become a very important part of dentistry today. However, we should not superimpose esthetic needs over functional needs. The loss of tooth structure associated with bruxism can be considered pathologic when it compromises the anterior guidance, which is the influence on mandibular movements that provides the contacting surfaces of the maxillary anterior teeth with the mandibular anterior teeth and avoids damaging eccentric contacts in the posterior teeth. The aim of this case report is to present a conservative way to restore both esthetics and function in a 34-year-old patient who came to the Prosthodontics Clinic of the Universidad Autónoma de Guadalajara in search of an esthetic appearance of her anterior teeth. After her initial evaluation, a diagnosis of anterior guide loss due to pathological wear associated with bruxism was made. Treatment included root canal treatment, removal of caries, and ill-fitting restorations, crowns, and veneers to reestablish the anterior guidance. The aesthetic expectations of the patient have met as well as the functional needs that were aimed from the beginning, achieving a conservative reestablishment of the anterior guidance system (AU)

Tabersonine alleviates wear particle-induced inflammatory osteolysis by inhibiting osteoclast activation / 中国组织工程研究

BACKGROUND:Tabersonine has shown good therapeutic effects in diseases such as myocardial remodeling,acute kidney injury and lung injury due to its anti-inflammatory biological activity.Prosthetic wear particles often lead to aseptic inflammation,and the massive release of inflammatory factors further promotes periprosthetic bone destruction and bone loss;however,there are no basic studies on the efficacy of tabersonine on periprosthetic osteolysis. OBJECTIVE:To investigate the effects of tabersonine on osteoclast activation,expression of inflammatory factors and inflammatory osteolysis induced by wear particles. METHODS:(1)Cell experiment:RAW264.7 cells were divided into four groups for culture.A complete medium was added in the control group.Osteoclast induction medium(50 ng/mL RANKL+complete medium)was added to the osteoclast induction group.1 and 5 μmol/L tabersonine was added for 4 hours,and then osteoclast induction medium was added to the low-and high-dose tabersonine groups,respectively.After 5 days of induction,tartrate-resistant acid phosphatase staining,F-actin staining and RT-PCR were performed.(2)Animal experiments:Twenty C57BL/6J mice were randomly divided into sham operation group,osteolysis group,low-dose tabersonine group and high-dose tabersonine group(n=5 per group).Skull osteolysis model of the skull was established by injecting titanium pellets on the skull surface in the osteolysis group,low-dose tabersonine group and high-dose tabersonine group.On day 2 after model establishment,mice in the low-dose and high-dose tabersonine groups received intraperitoneal injections of 10 and 20 mg/kg tabersonine every 2 days,respectively.2 weeks after surgery,mouse sera were collected for detecting inflammatory factors(interleukin 1β,interleukin 6,and tumor necrosis factor α),and cranial bones were collected for micro-CT scan and bone parameter analysis. RESULTS AND CONCLUSION:(1)Cellular experiments:Tartrate-resistant acid phosphatase staining and F-actin staining showed that compared with the osteoclast induction group,low-dose and high-dose tabersonine significantly inhibited osteoclast activation and bone resorption,and the inhibition was more significant in the high-dose tabersonine group.RT-PCR results showed that compared with the control group,the mRNA expressions of three kinds of inflammatory factors were increased in the osteoclast induction group(P<0.01).Compared with the osteoclast induction group,the mRNA expressions of three kinds of inflammatory factors were decreased in low-and high-dose tabersonine groups(P<0.01),and the decrease was more obvious in the high-dose tabersonine group.(2)Animal experiments:Compared with the sham operation group,the levels of three kinds of inflammatory factors were increased in the osteolysis group(P<0.01).Compared with the osteolysis group,the levels of three kinds of inflammatory factors were decreased in the low-and high-dose tabersonine groups(P<0.05,P<0.01),and the decrease was more obvious in the high-dose tabersonine group.The micro-CT scan results revealed that titanium particles caused the destruction of cranial osteolysis,and tabersonine could inhibit the osteolysis induced by titanium particles,especially in the high-dose tabersonine group.(3)The results confirm that tabersonine can enhance the osteolysis and bone destruction induced by titanium particles by inhibiting the release of inflammatory factors and down-regulating the bone absorption function of osteoclasts.

Novel programmed cell death in periprosthetic osteolysis / 中国组织工程研究

BACKGROUND:In addition to apoptosis,recent studies have discovered novel forms of programmed cell death in periprosthetic osteolysis,which is involved in regulating local chronic inflammation and the outcome of osteoblast and osteoclast under pathological conditions.This has an important value for the treatment and prognosis of periprosthetic osteolysis. OBJECTIVE:To provide new ideas and strategies for the prevention and treatment of periprosthetic osteolysis by summarizing studies on the novel forms of programmed cell death. METHODS:The first author used the computer to search the articles published from 2005 to 2022.Chinese search terms"wear particles,periprosthetic osteolysis,programmed cell death,apoptosis,autophagy,pyroptosis,necrotizing apoptosis,iron death"were used to search the databases of CNKI,WanFang and VIP.English search terms"osteolysis,wear debris,wear particles,peri*prosthetic osteolysis,PPOL,aseptic loosening,autophagy,regulated cell death,programmed cell death,apoptosis,pyroptosis,autophagic cell death,autophagy,necroptosis,ferroptosis"were used for search in PubMed and Web of Science databases.A total of 68 articles were finally included according to the inclusion criteria. RESULTS AND CONCLUSION:(1)Inadequate or excessive activation of autophagy can cause cell death,inhibit bone formation,and promote bone resorption,leading to bone metabolism disorders and osteolysis.(2)Recent studies have paid close attention to pyroptosis in periprosthetic osteolysis,where the Nod-like receptor,pyrin containing 3 inflammasome plays an important role in local inflammation.Inhibiting pyroptosis can effectively alleviate osteolysis.(3)In vitro studies have shown that necroptosis can inhibit the formation and function of osteoblasts and osteoclasts,affecting the process of osteolysis and destruction.(4)Ferroptosis is the newest form of programmed cell death,which is regulated by complex signaling pathways and mechanisms,but is not yet fully understood.(5)Autophagy,pyroptosis,necroptosis,and ferroptosis play important roles in the development of periprosthetic osteolysis,and their associated signaling pathways and genes require further investigation.

Prevalence of erosive tooth wear and associated risk factors in Colombian adolescents

Abstract Accurate determination of the prevalence of erosive tooth wear (ETW) and associated risk factors in adolescents can inform clinical management guidelines. The aim of this analytical cross-sectional study was to estimate the prevalence, severity, and risk factors of ETW in adolescents aged 12-15 years in the municipality of Usaquén in Bogotá, Colombia. Two calibrated examiners clinically assessed ETW using Basic Erosive Wear Examination (BEWE) Index (range: 0-3). All tooth surfaces (excluding proximal) were scored to allow estimation of the Highest (0-3) and Total BEWE (sum of Highest BEWE score per sextant: 0-18) scores per patient. Sociodemographic characteristics, ETW risk factors, and caries severity (ICDAS-epi-merged) were evaluated, and their association with the presence of ETW (indicated by a Highest BEWE score of 2-3) was examined using preliminary analyses and logistic regression models. The study sample included 454 adolescents (mean age: 13.5±1.1 years; female: 61.7%), and the prevalence of ETW was 71.6%. The majority of participants exhibited a Highest BEWE score of 3 (58.0%) and a Total BEWE score ≤8 (84.3%). The preliminary analysis showed an association between the presence of ETW and age, caries, and brushing teeth before eating (p-value < 0.05). Risk factors for ETW included always brushing teeth before eating [adjusted Prevalence Ratio (PRa) 1.31, p-value=0.014], presence of extensive carious lesions (PRa 1.23, p-value = 0.024), male gender (PRa 1.14, p-value = 0.028), and age > 14 years (PRa 1.17, p-value = 0.009). Although ETW was highly prevalent, most Colombian adolescents exhibited low Total BEWE scores. ETW was associated with frequent fruit intake, age, toothbrushing habits, caries lesions, and sex.

Can the combination of proanthocyanidin and vitamin E or palm oil effectively protect enamel against in vitro erosive and abrasive challenges?

Abstract Objectives This study aimed to assess the effect of proanthocyanidin, palm oil and vitamin E against erosive and erosive+abrasive challenges in vitro after enamel pellicle formation in situ. Methodology Bovine enamel blocks (n=84) were obtained and divided into the following treatment groups: negative control (NC) - deionized water; positive control (PC) - SnCl2/NaF/AmF-containing solution; palm oil (PO); 2% proanthocyanidin (P2); vitamin E (VitE); 2% proanthocyanidin+palm oil (P2PO); and 2% proanthocyanidin+vitamin E (P2VitE). For 5 days, one half of the sample from each group was subjected to erosion and the other half was subjected to erosion+abrasion. The acquired enamel pellicle (AEP) was pre-formed in situ for 30 minutes. The specimens were then treated in vitro with solutions (500 µl, 30s for each group). Subsequently, the blocks were left in the oral cavity for another hour to obtain the modified AEP. The blocks were immersed in 0.5% citric acid (pH=2.5) for 90s, 4×/day. AEP formation and treatment were carried out before the first and third erosive challenges, and after these challenges, abrasive cycles (15s) were performed on half of the samples. Enamel wear was quantified by profilometry and data were analyzed by two-way ANOVA and Tukey's test (p<0.05). Results All groups showed higher wear when exposed to erosion+abrasion than when exposed to erosion alone (p=0.0001). PO, P2VitE, P2, and P2PO showed enamel wear similar to the PC group, but only PC, PO and P2VitE differed from the NC group. The other groups behaved similarly to NC. Conclusion It was concluded that the combination of proanthocyanidin and vitamin E was effective in reducing wear in the face of in vitro erosive and erosive+abrasive challenges.

Efeito da adição de partículas bioativas ao gel clareador dental / Efeito da adição de partículas bioativas ao gel clareador dental

O estudo avaliou o efeito da adição de partículas bioativas ao gel clareador (peróxido de hidrogênio 35%, técnica de consultório), quanto ao clareamento e sobre a estrutura dental, além da resistência à desmineralização. O objetivo da primeira parte do estudo foi avaliar géis, com diferentes partículas bioativas e concentrações, para o potencial clareador e às alterações da estrutura dental. O objetivo da segunda parte foi avaliar géis, com diferentes partículas bioativas e concentrações, perante a suscetibilidade do esmalte ao protocolo cariogênico e ao desgaste dental erosivo. Espécimes de incisivos bovinos foram avaliados na primeira parte por análise da cor, microdureza Knoop e rugosidade. Os grupos foram controle negativo (CN), controle comercial (CCWhiteness HP), controle experimental (CE-gel sem partícula), controle positivo (CPsolução de peróxido), e os grupos experimentais onde as partículas bioativas S-PRG e 45S5 foram utilizadas nas concentrações de 5, 10, 15 e 20 %. Na segunda parte foram avaliados por microradiografia para a alteração da densidade mineral e profundidade da lesão perante o protocolo cariogênico e pela perfilometria para o desgaste dental erosivo. Os grupos foram CN, CC, CE, controle fluoreto (CF), e os grupos experimentais onde as partículas bioativas S-PRG e 45S5 foram utilizados nas concentrações de 15 e 20 % apenas. Os dados foram analisados estatisticamente para verificar a diferença entre os grupos (α=5%). Para a mudança de cor (∆E*00) foi observada diferença apenas para o fator partícula, S-PRG-3,37(0,48)a e 45S5-3,67(0,76)b. Todos os grupos experimentais foram estatisticamente iguais o CP e diferentes do CN. Para a microdureza (KNH%) foi observada diferença para a interação dos fatores, sendo o S-PRG 20% o grupo com maior aumento da microdureza. Todos os grupos experimentais foram diferentes e maiores que CP, CC e CE. Não foram observadas diferenças de rugosidade entre os grupos. Para a alteração da densidade mineral foi observada diferença para a interação dos fatores e tempo. Os grupos S-PRG 15% e 20% foram os grupos que apresentaram a menor alteração da densidade mineral em todos os tempos testados. Aos 14 e 21 dias o SPRG 20% foi diferente do CN e semelhante ao CF. Para a profundidade da lesão foram observadas diferenças estatísticas para o fator partícula e tempo, S-PRG206,8(59,2)a e 45S5 230,0(63,7)b, 7 dias-148,9(19,7)a, 14 dias-217,7(22,5)b e 21 dias288,7(30,7)c. Aos 14 e 21 dias o S-PRG 20% foi diferente do CN e semelhante ao CF. Para o desgaste foi observada diferença apenas para o tempo, 5 dias-1,2(0,2)a e 10 dias-2,3(0,3)b. Conclui-se que: a adição de partículas bioativas não reduziu a efetividade clareadora, contribuiu para o aumento da microdureza e não alterou a rugosidade. Além disso, o grupo S-PRG com 20% teve suscetibilidade à desmineralização por cárie semelhante ao grupo controle fluoreto e nenhum grupo alterou a suscetibilidade ao desgaste dental erosivo (AU)

The study evaluated the consequences of bioparticle addition on tooth bleaching gel (hydrogen peroxide 35%, in-office technique), for its bleaching effect and changes on tooth structure, also for resistance against demineralization. The aim of the first part of the study was to evaluate bleaching gels containing different bioactive particles and concentrations over the bleaching potential and possible dental structural changes. The objective of the second part was to evaluate bleaching gels containing different bioactive particles and concentrations to assess enamel susceptibility to cariogenic and erosive tooth wear protocols after bleaching treatments. Bovine incisors specimens were used in the first part for analysis of color, Knoop microhardness and roughness. The groups were negative control (NC), commercial control (CCWhiteness HP), experimental control (EC-gel without particles), positive control (PCperoxide solution), and experimental groups were the bioactive particles S-PRG and 45S5 used in concentrations of 5, 10, 15, and 20 %. In the second part, specimens were evaluated using advanced transverse microradiography to assess the change in mineral density and lesion depth in response to the cariogenic protocol, and profilometry to measure wear in response to the erosive tooth wear protocol. The groups were NC, CC, EC, fluoride control (FC), and experimental groups were the bioactive particles S-PRG and 45S5 used only in concentrations of 15 and 20 %. The data were statistically analyzed to verify the differences between the groups (α=5%). For the color change (∆E*00), a difference was observed only for particle, S-PRG3,37(0,48)a and 45S5-3,67(0,76)b. All experimental groups were statistically similar to PC and different from NC. For the microhardness (KNH%), difference was observed for factors interaction, S-PRG 20% was the group with higher hardness increase. All experimental groups were different and higher than PC, CC, and EC. No roughness differences were observed between groups. For the mineral density alteration differences were observed for factors interaction and time. S-PRG 15% and 20% presented the lower mineral density change for all measurements times. On 14 and 21 days S-PRG 20% was different from NC and similar to FC. For lesion depth differences were observed for factor particle and time, S-PRG-206,8(59,2)a and 45S5- 230,0(63,7)b, 7 days-148,9(19,7)a, 14 days-217,7(22,5)b and 21 days-288,7(30,7)c. On 14 and 21 days S-PRG 20% was different from NC and similar to FC. For wear the only difference was for time, 5 days-1,2(0,2)a and 10 days-2,3(0,3)b. It was concluded that the addition of bioactive particles did not reduce the bleaching effectiveness, it contributed to microhardness increase and did not change roughness. Furthermore, the S-PRG group with 20% susceptibility to cariogenic demineralization was similar to the fluoride control group, and no group showed a change in susceptibility to erosive tooth wear (AU)

PREVENTIVE EFFECT OF CRANBERRY GEL ON DENTIN SUBMITTED TO EROSION

Aims: Considering that Cranberry's components might inhibit dentin metalloproteinases exposed to erosive agents, the aim of this study was to evaluate in situeffect of a Cranberry gel application on dentin before an erosive challenge.Materials and methods: This crossover double-blinded study was performed in 2 phases of 5 days each, with 10 healthy volunteers who wore 2 palatal devices (1 for each phase) with 4 dentin specimens (2 specimens for each group). The groups under study were:First Phase: G1 -Erosivechallenge (Coca-cola®) over dentin without any previous treatment (1st negative control group); G2 -Erosive challenge over dentin previously treated with Cranberry gel (test group); and Second Phase: G3 -Erosive challenge over dentin previously treated with a gel without any active principle (2ndnegative control group); G4 -Erosive challenge over dentin previously treated with 0.12% Chlorhexidine gel (positive control group). Each device was immersed into the acid beverage, 3 times daily for 5 minutes during 5 days. Profilometry (µm) was used to quantify the dentin wear. Data were analyzed by Repeated Measures Analysis of Variance followed by Fisher's test (p<0.05).Results: Data (G1: 4.98 ± 1.36a; G2: 3.29 ± 1.16b; G3: 4.38 ± 1.19a; G4: 3.32 ± 1.55b) showed no statistical difference between G1 and G3. There was also no difference between G2 and G4. However, G2 and G4 presented lower wear when compared to G1 and G3, and this difference was statistically significant. Conclusion: The results of this studysuggest a significant efficacy of Cranberry gel in preventing wear of dentin subjected to dental erosion.

Rendimiento Clínico de las Restauraciones Adhesivas con Resina Compuesta en Casos de Pacientes con Desgaste Severo e Incremento de Dimensión Vertical: Revisión de Literatura Sistematizada / Clínical Performance of Adhesive Restorations with Composite Resin in Cases of Patients with Severe Wear and Increased Vertical Dimension: Systematized Literature Review

El desgaste dental severo se describe como la pérdida sustancial de la estructura dental, con exposición de la dentina y pérdida significativa de igual o más de 1/3 de la corona clínica. El uso de materiales compuestos de resina permite al clínico ser más conservador, debido a su aplicación mínimamente invasiva. Además de ello, son relativamente económicas, proporcionan buena estética general, así como un buen rendimiento y facilidad en la reparación. El objetivo de esta revisión de literatura sistematizada es recopilar información disponible en la literatura referente a cuál es el rendimiento clínico de las restauraciones adhesivas con resina compuesta en casos de pacientes con desgaste severo e incremento de la dimensión vertical como objetivo rehabilitador. Se analizaron artículos entre los años 2000 y 2022, seleccionando cuatro bases de datos (Pubmed, Scopus, Scielo y Web of Science). Para identificar los descriptores se utilizó los Medical subject headings (Mesh): Tooth Wear, Composite Restorations, Resin y Oral Rehabilitation. No se aplicó restricciones de idioma, país de origen, autor o lugar de publicación donde se realizó el estudio. Como resultado de la búsqueda se obtuvieron 71 artículos, de los cuales se seleccionaron 5 que cumplieron con los criterios de elegibilidad para ser considerados en la revisión de literatura sistematizada. Se encontró un promedio de tasa de éxito ente el 89,4 % - 100 % en un promedio total de 5.2 años de seguimiento. Se puede concluir, hasta donde se tiene conocimiento en la literatura científica disponible, que el tratamiento de restauraciones adhesivas con resinas compuestas en pacientes con desgaste severo es recomendable, enfocado en un periodo a corto-mediano plazo (3-5 años), siendo una opción de tratamiento económica y mínimamente invasiva.

Severe tooth wear is described as the substantial loss of tooth structure, with dentin exposure and significant loss of equal to or more than 1/3 of the clinical crown. The use of resin composite materials allows the clinician to be more conservative, due to its minimally invasive application. In addition to this, they are relatively inexpensive, provide good general aesthetics, as well as good performance and ease of repair. The objective of this systematic literature review is to collect information available in the literature regarding the clinical performance of adhesive restorations with composite resin in cases of patients with severe wear and increase in the vertical dimension as a rehabilitation objective. Articles between the years 2000 and 2022 were analyzed, selecting four databases (Pubmed, Scopus, Scielo and Web of Science). To identify the descriptors, the Medical subject headings (Mesh) were used: Tooth Wear, Composite Restorations, Resin and Oral Rehabilitation. No language, country of origin, author or place of publication restrictions where the study was conducted were applied. As a result of the search, 71 articles were obtained, of which 5 were selected that met the eligibility criteria to be considered in the systematic literature review. An average success rate between 89.4 % - 100 % was found in a total average of 5.2 years of follow-up. It can be concluded, to the best of our knowledge in the available scientific literature, that the treatment of adhesive restorations with composite resins in patients with severe wear is recommendable, focused on a short-medium term period (3-5 years), being a Inexpensive and minimally invasive treatment option.

Lesiones cervicales no cariosas: una revisión sistemática / Non carious cervical lesions: a systematic review

Introducción: las lesiones cervicales no cariosas (NCCL, por sus siglas en inglés) son un grupo de lesiones que afectan el área cervical del órgano dental causando hipersensibilidad dentinaria y defectos estéticos. Objetivo: analizar la literatura sobre las lesiones cervicales no cariosas, su etiología, consideraciones anatómicas, características morfológicas de la lesión y tratamientos no restaurativos. Material y métodos: se realizó una búsqueda en la base de datos PubMed, utilizando las palabras clave: non-carious cervical lesions OR noncarious cervical lesions OR tooth wear OR tooth erosion OR dental abfraction OR abfraction, recopilando un total de 78 artículos. Resultados: es necesario determinar la etiología antes de seleccionar las estrategias de tratamiento para las lesiones cervicales no cariosas. Conocer los distintos tipos de tejidos que componen al órgano dentario facilita la comprensión de los factores que participan en el desarrollo de las lesiones cervicales no cariosas. Esto permite que el tratamiento se enfoque más en la causa del problema que en los síntomas. Con esto podemos modificar diversos factores de manera interceptiva, los tratamientos de terapia con láser y compuestos tópicos son una estrategia mínimamente invasiva. Conclusiones: la mejor manera de describir a las lesiones cervicales no cariosas sería como una enfermedad multifactorial. Se debe prestar especial atención en los métodos de diagnóstico, identificando cofactores que propicien el avance de la lesión, como son la fricción y la biocorrosión. Esta revisión brinda datos que asocian a los factores oclusales como una de las principales causas de una enfermedad que afecta a más de la mitad de la población adulta (AU)

Introduction: non-carious cervical lesions (NCCL) are a group of lesions that affect the cervical area of the dental organ causing dentin hypersensitivity and cosmetic defects. Objective: to know, through a systematic review, the current state of non-carious cervical lesions. Material and methods: a search was conducted in the PubMed database, using the keywords: non-carious cervical lesions OR noncarious cervical lesions OR tooth wear OR tooth erosion OR dental abfraction OR abfraction, compiling a total of 78 articles. Results: determining etiology is necessary before selecting treatment strategies for non-carious cervical lesions (NCCL). Know the different types of tissues that make up the dentary organ, facilitate the understanding of the factors involved in the development of noncarious al cervical lesions. This allows treatment to focus more on the cause of the problem than on symptoms. With this we can modify various factors in an interceptive way, laser therapy treatments and topical compounds, are a minimally invasive strategy. Conclusions: the best way to describe non-carious al cervical lesions would be as a multifactorial disease to which special attention should be paid to both diagnostic methods, identifying cofactors that promote the progression of injury, such as friction and biocorrosion. This review provides data that associates occlusal factors as one of the main causes of a disease that affects more than half of the adult population (AU)

STUDY ON THE EFFECT OF BRASS AND COPPER ELECTRODES DURING ELECTRIC DISCHARGE MACHINING OF INCONEL 718 USING NANO PARTICLES MIXED DIELECTRIC FLUID.

Electrical Discharge Machine (EDM) parameters have a significant influence on machining characteristic like material removal rate (MMR) and tool wear rate (TWR). Inconel 718, which is widely used in the Medical, Marine, Architectural and food processing industries, is used as a work material. The tool electrode materials used are brass and copper. Experiments are conducted using face centered central composite design to determine the effects of process parameters like current rate, pulse on time, pulse off time and concentration of titanium carbide nano particle in dielectric fiuid. Based upon the experimental outcomes, the effect of brass and copper electrodes during electric discharge machining of Inconel 718 using nano particles mixed dielectric fiuid was investigated.

Cargas de trabalho de profissionais técnico-administrativos de uma instituição pública de ensino superior / Workloads of technical-administrative professionals at a public institution of higher education

Resumo: A saúde do trabalhador tem se deparado com novos desafios advindos, por exemplo, da pandemia da covid-19 e da indústria 4.0, o que implica na inevitabilidade de refletir sobre as cargas de trabalho nesse contexto. A dissertação que se segue tem como objetivo analisar as cargas de trabalho presentes no processo laboral dos técnico-administrativos de uma instituição pública de ensino superior no contexto da pandemia da covid-19. Sugere-se também reconhecer as estratégias utilizadas para o enfrentamento dessas cargas no meio laboral. Trata-se de uma pesquisa do tipo exploratória e descritiva, de natureza qualitativa. O estudo se dá na região sul do Brasil. Para esse fim, propõe-se a criação e testagem de um instrumento para identificar as cargas de trabalho que podem causar impactos negativos ou desgaste desses trabalhadores. Os pesquisadores Asa Laurell e Mariano Noriega (1989) orientam o referencial teórico do estudo, a partir do conceito de Cargas de Trabalho, classificadas em físicas, químicas, biológicas, mecânicas, fisiológicas e psíquicas. A coleta de dados se estabelece a partir da aplicação do instrumento criado, um questionário aplicado por meio de entrevista (presencial ou online), com 31 técnico-administrativos que exercem o cargo de secretário(a) nas coordenações de cursos de graduação de uma universidade pública federal. O tratamento dos dados se dá com base na Análise de Conteúdo Temática de Laurence Bardin (2016), com a proposição de duas categorias finais: a primeira sobre o reconhecimento das cargas de trabalho dos técnico-administrativos. Nessa categoria são apresentadas as cargas de trabalho que causam ou podem gerar algum tipo de desgaste nos trabalhadores. O percurso de investigação mostra que as cargas mais reconhecidas pelos trabalhadores pesquisados, a partir de sua percepção do processo de trabalho, são as psíquicas e fisiológicas, com atenção para as condições ergonômicas do trabalho. A segunda categoria, sobre as estratégias individuais e coletivas utilizadas por esses trabalhadores para o enfrentamento das cargas de trabalho, evidencia que os técnico-administrativos utilizam mecanismos individuais e coletivos como medidas protetivas contra os agravos decorrentes do labor, porém esses fatores de proteção requerem aprimoramento. Esses achados corroboram com o que traz a literatura sobre a presença dessas cargas nos ambientes de trabalho, principalmente nas áreas de prestação de serviços e atendimento a pessoas. Uma vez reconhecida a existência das cargas de trabalho, pode-se propor medidas de promoção à saúde e prevenção de doenças dos técnico-administrativos.

Abstract: Worker's health has faced new challenges arising, for example, the covid-19 pandemic and Health 4.0, which implies the inevitability of reflecting on workloads in this context. Therefore, the following dissertation aims to analyze the workloads present in the work process of administrative technicians at a public institution of higher education in the context of the covid-19 pandemic. It is also suggested to recognize the strategies used to face these workloads in the work environment. This is an exploratory and descriptive research, with a qualitative nature. The study takes place in the southern region of Brazil. This academic work proposes the creation and testing of an instrument (questionnaire) to identify the workloads that can cause negative impacts or cause wear on these Workers. Researchers Asa Laurell and Mariano Noriega (1989) guide the theoretical framework of the study, based on the concept of Workloads, classified as physical, chemical, biological, mechanical, physiological and psychological. For the data collection, the questionnaire was applied through interviews (in person or online), with 31 administrative technicians who work as secretary in the coordination of undergraduate courses at a federal public university. Data treatment is based on Laurence Bardin's Thematic Content Analysis (2016), with the proposition of two final categories: the first one is the recognition of administrative technical workers workloads. This category presents the workloads that cause or may generate some type of wear on workers. The investigation shows that the workloads most recognized by the surveyed, based on their perception of the work process, are psychic and physiological, with attention to the ergonomic conditions of work. The second category, about the individual and collective strategies used by these workers to handle with workloads, shows that the administrative technical workers use individual and collective mechanisms as protective measures against the damage resulting from work, but these protection factors require improvement. These findings corroborate with what the literature brings about the presence of these loads in work environments, especially in the areas of service provision and assistance to people. Once the existence of workloads is recognized, measures can be proposed to promote health and prevent diseases for these administrative technical workers.

Non-compliance for wearing spectacles: Prevalence and determinants in school-going children in South India

Purpose: To study the prevalence and determinants of compliance with spectacle wear among school?age children in South India who were given spectacles free of charge under a school vision screening program. Methods: A cross?sectional, descriptive study was performed. The participants were recruited from the school from Tirunelveli and Tuticorin districts of Tamil Nadu, where a school vision screening camp was conducted between January 2012 and October 2012. The school screening was performed under “Lavelle Pediatric Eye Care Project”. Of the 129,720 children examined of 249 schools, 4253 of children had refractive error and 3333 were prescribed and dispensed spectacles. A total of 683 children were interviewed, who were not wearing glasses on follow?up. Results: About 20% of the participants (683/3333) were not wearing their spectacles at examination. The most common reasons given for non?wear were lost (44.9%) or broken (35.3%) spectacles. There was no gender preference on compliance to spectacles. Conclusion: Compliance with spectacle wear is less even when spectacles are provided free of cost, particularly in children among the age group of 5–15 years. Because factors such as type of school, area (urban or rural), parent’s income, occupation, and their education were not significantly affecting the compliance of spectacle wear, proper encouragement and counseling of the parents and the child become extremely important.

Research on friction and wear behaviors of silicon-lithium spray coating on zirconia ceramics / 北京大学学报(医学版)

OBJECTIVE@#To study microstructure, friction and wear behaviors of silicon-lithium spray coating on the surface of zirconia ceramics and to preliminarily evaluate its esthetic so as to provide support and guidance for the clinical application.@*METHODS@#Zirconia ceramic specimens were randomly divided into three groups: coating group (two subgroups), polishing group (two subgroups), and glazing group (four subgroups), with 10 samples in each subgroup. The two subgroups of coating group were the zirconia ceramics with the untreated and preliminary polishing surfaces sprayed with silicon-lithium coating, respectively. The two subgroups of polishing group were preliminary polishing and fine polishing of zirconia ceramics, respectively. The four subgroups of glazing group were preliminarily polished zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively; and untreated zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively. The above 8 subgroups of zirconia ceramic specimens were used as friction pairs with 80 steatite ceramics for 50 000 chewing cycles under 50 N vertical load and artificial saliva lubrication using chewing simulation. Scanning electron microscope was used to observe the microstructure of the surface and section of the coating group, and the thickness of the coating and glazing were measured. The linear roughness of the coating and polishing groups was mea-sured using a laser confocal scanning microscope. Vickers hardness was measured using a microhardness tester and the esthetic of zirconia ceramic full crown sprayed with silicon-lithium coating was preliminarily evaluated. White light interferometer was used to measure the width, the maximum depth and the volume of the wear scars of each group, and the wear depth of steatite ceramics and wear rate of zirconia ceramic specimens were calculated. Kruskal-Wallis nonparametric test and Dunn's multiple comparisons test were used to analyze the wear depth of each group (α=0.05).@*RESULTS@#The microstructures of the silica-lithium spray coatings on the untreated and preliminarily polished zirconia ceramic surfaces showed the protruding defects, and the line roughness of coating group was larger than that of the polishing group. The median thickness of the silica-lithium spray coating on the preliminarily polished zirconia ceramic was 13.0 μm (interquartile range, IQR: 11.6, 17.9), while that of the silica-lithium spray coating on the untreated zirconia ceramic was 4.4 μm (IQR: 4.1, 4.7). The Vickers hardness and wear rate of the coating group were between the polishing group and the glazing group. The wear depths of the wear scars of steatite ceramics were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference between glazing and polishing groups (P < 0.05). With the increase of polishing procedure, the wear depth of steatite ceramics decreased in each subgroups. The orders of maximum depth and volume of wear scars of zirconia ceramic were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference in the maximum depth of wear scars between glazing and polishing groups (P < 0.05).@*CONCLUSION@#The silica-lithium spray coating on the zirconia ceramic, can be used as a new method for zirconia ceramic surface treatment, because it can increase the esthetic of zirconia ceramics compared with polishing and reduce the wear of steatite ceramics compared with glazing.

The Wear on a Novel Motion Mode Hinged Knee Prosthesis: A Finite Element Analysis / 医用生物力学

Objective To perform finite element analysis on a novel motion mode hinged knee prosthesis, and investigate the method of wear simulation on hinged prosthesis and the influence of motion mode on wear of the prosthesis. Methods Based on the finite element model of contact stress on spherical axis prosthesis, the finite element model of wear was established according to Archard wear theory. The kinematics data during different motions were input as loading condition to simulate mechanical environment of the knee arthroplasty in physiological activities. The wear results of spherical axis prosthesis were studied. Results For tibial insert, the average and maximum contact stresses during upstairs and downstairs climbing were higher than those during walking, and the cumulative wear volume during upstairs climbing was larger than that during downstairs climbing and walking. The wear mainly occurred on lower surface of tibial insert during all 3 motions. For rotating bushing, there was only a short period of contact and wear during walking, and the cumulative wear was 0. 19 mm3. Conclusions The spherical axis motion of hinged knee prosthesis can improve the mechanical environment of knee, reduce the wear of rotating bushing, and prolong the prosthesis survival. The finite element simulation can predict the wear of hinged prosthesis effectively, and provide the theoretical basis for design and improvement of the prosthesis.

Effect of prosthetic joint line installation height errors on insert wear in unicompartmental knee arthroplasty / 生物医学工程学杂志

The clinical performance and failure issues are significantly influenced by prosthetic malposition in unicompartmental knee arthroplasty (UKA). Uncertainty exists about the impact of the prosthetic joint line height in UKA on tibial insert wear. In this study, we combined the UKA musculoskeletal multibody dynamics model, finite element model and wear model to investigate the effects of seven joint line height cases of fixed UKA implant on postoperative insert contact mechanics, cumulative sliding distance, linear wear depth and volumetric wear. As the elevation of the joint line height in UKA, the medial contact force and the joint anterior-posterior translation during swing phase were increased, and further the maximum von Mises stress, contact stress, linear wear depth, cumulative sliding distance, and the volumetric wear also were increased. Furthermore, the wear area of the insert gradually shifted from the middle region to the rear. Compared to 0 mm joint line height, the maximum linear wear depth and volumetric wear were decreased by 7.9% and 6.8% at -2 mm joint line height, and by 23.7% and 20.6% at -6 mm joint line height, the maximum linear wear depth and volumetric wear increased by 10.7% and 5.9% at +2 mm joint line height, and by 24.1% and 35.7% at +6 mm joint line height, respectively. UKA prosthetic joint line installation errors can significantly affect the wear life of the polyethylene inserted articular surfaces. Therefore, it is conservatively recommended that clinicians limit intraoperative UKA joint line height errors to -2-+2 mm.

Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro

Abstract: This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.

Facetas de desgaste por atrição em criancas brasileiras e má oclusão: um estudo trasnversal / Attribution wear facets in brazilian children and malocclusion: a transversal study / Hechos de gasto de atracción en niños brasileños y mal occusión: un estudio trasnversal

O objetivo do estudo foi avaliar a associação entre facetas de desgaste por atrição e má oclusão em escolares brasileiros. Este estudo transversal realizado com 433 escolares de 8 a 10 anos, junto a seus pais/responsáveis, das redes pública e privada na cidade de Diamantina. Informações sobre sociodemográfico da família da criança e saúde geral da criança foram colhidos a partir de um questionário previamente estruturado, direcionado aos pais/cuidadores. Foram realizados exame intrabucal em cada criança para avalição da presença de facetas de desgaste por atrição, perda de tecido dentário por erosão, ausência/presença de má oclusão e traumatismo dentário. Os resultados foram obtidos a partir da análise descritiva de frequência absoluta e relativa dos dados e analise de Regressão de Poisson (IC 95%; p<0,05). Os resultados mostraram uma prevalência de crianças com facetas de desgaste de 73,7%, a sobressaliência anterior superior (RP= 1,16; IC: 95%; 1,03-1,31; p= 0,014) e a relação molar (RP=1,15; IC 95%: 1,00­1,29; p=0,030) associadas a presença de facetas de desgastes por atrição, e o apinhamento dentário (RP: 0,87; IC: 95%; 0,78-0,98; P= 0,023) um fator de proteção para a facetas de desgaste em escolares, independentemente do sexo e idade da criança. Os resultados do presente mostraram que a alta prevalência de facetas de desgaste, sendo a sobressaliência anterior superior e a relação molar associadas a presença desse desgaste dentário. Dessa forma, os dados sinalizam a necessidade dos cirurgiões-dentistas estarem atentos a presença de desgaste fora dos padrões fisiológicos e relacionados a presença de má-oclusão.

The aim of the study was to evaluate the association between attrition wear facets and malocclusion in Brazilian schoolchildren. This cross-sectional study was carried out with 433 schoolchildren aged 8 to 10 years, along with their parents/guardians, from public and private schools in the city of Diamantina. Information about the child's family sociodemographic and general health was collected from a previously structured questionnaire, directed to parents/caregivers. Intraoral examinations were performed on each child to assess the presence of attrition wear facets, loss of dental tissue by erosion, absence/presence of malocclusion and dental trauma. The results were obtained from the descriptive analysis of absolute and relative frequency of data and Poisson Regression analysis (95% CI; p<0.05). The results showed a prevalence of 73.7% of children with wear facets, superior anterior overjet (PR= 1.16; CI: 95%; 1.03-1.31; p= 0.014) and molar relationship ( PR=1.15; 95% CI: 1.00­1.29; p=0.030) associated with the presence of attrition wear facets, and dental crowding (PR: 0.87; CI: 95%; 0. 78-0.98; P= 0.023) a protective factor for wear facets in schoolchildren, regardless of gender and age of the child. The present results showed that the high prevalence of wear facets, with superior anterior overjet and molar relationship associated with the presence of this tooth wear. Thus, the data indicate the need for dentists to be aware of the presence of wear outside of physiological standards and related to the presence of malocclusion.

objetivo del estudio fue evaluar la asociación entre las facetas del desgaste por atracción y la pobre oclusión en las escuelas brasileñas. Este estudio transversal se llevó a cabo con 433 escuelas de 8 a 10 años de edad, con sus padres/directores, en redes públicas y privadas de la ciudad de Diamantina. La información sobre la sociodemografía familiar del niño y la salud general del niño se recopiló a partir de un cuestionario preestructurado dirigido a los padres y cuidadores. En cada niño se realizó un examen intraabucal para evaluar la presencia de rasgos de desgaste, pérdida de tejido dental por erosión, ausencia/presencia de maloclusión y trauma dental. Los resultados se obtuvieron a partir del análisis descriptivo de la frecuencia absoluta y relativa de los datos y análisis de la regresión de Poisson (IC 95%; p<0,05). Los resultados mostraron una prevalencia de niños con facetas de desgaste del 73,7%, sobresaliencia anterior superior (RP= 1,16; IC del 95%; IC del 1,03-1,31; p= 0,014) y relación molar (RP=1,15; IC del 95%: 1,00-1,29; p=0 030) asociada a la presencia de facetas de fragancia por atracción, y de plomería dental (RP: 0,87; IC: 95%; 0,78-0,98; P= 0,023), un factor de protección para las facetas de desgaste en las escuelas, independientemente del género y la edad del niño. Los resultados de la presente muestra que la alta prevalencia de las facetas desgaste, con la proyección de legado superior y la relación molar asociada con la presencia de este desgaste dental. Así pues, los datos indican la necesidad de que los cirujanos dentales estén alerta ante la presencia de desgaste y desgaste fuera de las normas fisiológicas y relacionados con la presencia de maloclusión.

Prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous populations in Brazil: a systematic review and meta-analysis

Abstract The aim of this review was to evaluate the prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous in Brazil. A systematic review of observational studies was performed according to the PRISMA guidelines (CRD42020218704). The search strategy involved the electronic databases of Embase, LILACS, PubMed, Web of Science, Scopus, and the CAPES Theses and Dissertations for gray literature. The eligibility criteria consisted of publications that assessed the prevalence of oral conditions in indigenous populations in Brazil. Studies with indigenous people living in urban area were excluded. The risk of bias was evaluated by using JBI Critical Appraisal for prevalence studies. Thirty studies were included in the review, and the majority showed a low risk of bias. A meta-analysis of 20 studies was conducted using the random-effects model and a 95% confidence interval. Several ethnicities were studied in isolation or in groups (n = 7,627 for dental caries; n = 2,774 for periodontal disease; n = 1,067 for malocclusion; n = 150 for tooth wear). The prevalence of caries ranged from 50% among indigenous people aged 18-36 months to 100% among those aged 65-74 years. The prevalence of periodontal disease ranged from 58% to 83%. The prevalence of malocclusion was 43%. Tooth wear was assessed in only one ethnic group and showed a prevalence of 100% in indigenous people aged >18 years. The certainty of evidence assessed by the GRADE system ranged from very low to moderate. This systematic review showed significant differences in the prevalence of dental caries, periodontal disease and malocclusion between indigenous population groups and territories in which indigenous people live.

Fluorotic Enamel Susceptibility to Dental Erosion and Fluoride Treatment

Abstract The purpose of this in vitro study was to test the hypothesis that fluoride treatment can prevent dental erosion on fluorotic enamel of different severities. It followed a 3×2 factorial design, considering a) fluorosis severity: sound (TF0, Thylstrup-Fejerskov Index), mild (TF1-2), moderate (TF3-4); and b) fluoride treatment: 0 (negative control) and 1150ppmF. Human molars with the three fluorosis severities (n=16, each) were selected and randomly assigned to the two fluoride treatments (n=8). Enamel blocks (4×4mm) were prepared from each tooth and subjected to a dental erosion cycling model, for 10 days. The daily cycling protocol consisted of erosive challenges (1% citric acid, pH 2.4), interspersed by periods of immersion in artificial saliva, and three 2-minute treatments with either 0 or 1150ppm F. The enamel volume loss (mm3) was calculated by subtracting values obtained by microtomography before and after cycling. Two-Way ANOVA showed no significant interaction between fluorosis severity and fluoride treatment (p=0.691), and no significant effect for either fluorosis severity (TF0 mean±standard-deviation: 13.5(10-2±0.42(10-2, TF1-2: 1.50(10-2±0.52(10-2, TF3-4: 1.24(10-2±0.52(10-2, p=0.416) or treatment (0ppmF: 1.49(10-2±0.53(10-2; 1150ppmF: 1.21(10-2±0.42(10-2; p=0.093), when evaluated independently. Considering the limitations of this in vitro study, the presence and severity of fluorosis in enamel do not appear to affect its susceptibility to dental erosion. Fluoride treatment was not effective in preventing the development of dental erosion in both sound and fluorotic enamel substrates under our experimental conditions.

Resumo Este estudo in vitro foi testou a hipótese de que o tratamento com flúor pode prevenir a erosão dentária no esmalte fluorótico de diferentes severidades. O objetivo deste estudo foi: investigar o efeito protetor dos fluoretos contra a erosão e abrasão simuladas no esmalte fluorótico. Seguiu um desenho fatorial 3×2, considerando a) severidade da fluorose em 3 níveis: hígido (TF0, Índice Thylstrup-Fejerskov), suave (TF1-2), moderada (TF3-4); b) tratamento com flúor: 0 (controle negativo) e 1150ppmF. Molares humanos com as três severidades de fluorose (n=16, cada) foram selecionados e distribuídos aleatoriamente para os dois tratamentos com flúor (n=8). Blocos de esmalte (4×4mm) foram preparados a partir de cada dente e submetidos a um modelo de ciclo de erosão dentária, por 10 dias. O protocolo de ciclagem diária consistiu em seis desafios erosivos de 5 minutos (1% de ácido cítrico, pH 2,4), intercalados por seis períodos de imersão em saliva artificial e três tratamentos de 2 minutos com 0 ou 1150ppmF. O volume do esmalte perdido foi calculado subtraindo o perfil superficial 3D obtido por microtomografia antes e depois da ciclagem. A ANOVA de dois fatores não mostrou interação significativa entre a severidade da fluorose e o tratamento com flúor (p = 0,691) e nenhum efeito significativo para a severidade da fluorose (TF0 média+/desvio padrão: 13,5(10-2±0,42(10-2, TF1-2: 1,50(10-2±0,52(10-2, TF3-4: 1,24(10-2±0,52(10-2, p=0,416) ou tratamento (0: 1,49(10-2±0,53(10-2; 1150ppmF: 1,21(10-2±0,42(10-2, p=0,093), quando avaliados independentemente. Considerando as limitações deste estudo in vitro, a presença e severidade da fluorose no esmalte não parece afetar sua suscetibilidade à erosão dentária. O tratamento com flúor não foi eficaz na prevenção do desenvolvimento da erosão dentária em esmalte hígido e fluorótico, sob as condições experimentais utilizadas.