The use of rubber dam in the survival of RMGIC restorations in primary molars: a 30-month randomized controlled clinical trial

Abstract This study was a randomized controlled clinical trial with two parallel arms and the objective was to compare the survival of resin modified glass ionomer (RMGIC) restorations in primary teeth using rubber dam or cotton roll isolation after a 30-month follow-up period. Ninety-two children (mean age 6.8 ± 1.37) and 200 primary molars with occlusal or occluso-proximal cavitated dentin caries lesions were randomly assigned into two groups: cotton rolls and rubber dam. All lesions were restored using RMGIC (RIVA Light Cure) after selective caries removal. Restorative failure and lesion arrestment were evaluated by two independent, trained, and calibrated examiners through clinical and radiographic examinations. The Kaplan-Meier test was used to assess the survival of restorations and Cox regression was used to assess the association of risk factors with restorative failure. There was no significant difference in survival rates between groups (p = 0.17). Older age (HR = 2.81 [95%CI: 1.47-5.44]) and higher rate of gingival bleeding (HR = 0.47 [95%CI: 0.23-0.99]) were associated with restorative failure. No patient had painful symptoms, pulp outcomes, or radiographic changes compatible with lesion progression. The use of rubber dam isolation did not increase the survival rate of occlusal and occluso-proximal restorations using RMGIC in primary molars after 30 months of follow-up. Since the survival is not influenced by the type of isolation, the professional can safely choose the appropriate technique for each case, considering his experience and preferences, as well as those of the patient.

In vitro characterization of a novel resin-based restorative material containing alkaline fillers

Abstract Objective: In this study, a comparative evaluation of the physicochemical properties of Cention N and other direct restorative materials was performed. Three restorative materials—a resin-modified glass ionomer (Fuji II LC), an alkasite-based resinous material (Cention N), and a resin composite (Tetric N Ceram)—were characterized in terms of degree of conversion, Knoop hardness number (KHN) ratio, flexural strength, elastic modulus, water sorption, water solubility, microshear bond strength to dentin, immediate microleakage, and radiopacity. Methodology: The microshear bond strength to dentin and microleakage of Cention N were evaluated with and without the application of an adhesive system (Tetric N Bond Universal). A one-way ANOVA test was used to analyze the data in terms of degree of conversion, KHN ratio, water sorption, water solubility, microshear bond strength to dentin, and radiopacity. A two-way ANOVA test (carried out considering the material type and ethanol aging as factors) was used to analyze the data in terms of flexural strength and elastic modulus. The Kruskal-Wallis test was used to statistically analyze the data on microleakage. A significance level of α=0.05 was used for all tests. Results: Fuji II LC was found to have the highest degree of conversion, water sorption, and microleakage, as well as the lowest flexural strength. Cention N had the highest solubility; when used with an adhesive system, it achieved bond strength and microleakage similar to those of the Tetric N Ceram composite. Tetric N Ceram had the highest degree of conversion, KHN ratio, and radiopacity. Conclusion: The properties of Cention N validate its efficacy as an alternative direct restorative material when used in conjunction with an adhesive system.

Comparative study of physical-chemical properties of bioactive glass ionomer cement

Abstract This study analyzed the physical-chemical properties of bioactive ionomer materials. Cention N bioactive materials were evaluated chemically activated (CN) and light-cured (CN-LC), Equia Forte Fill (EQUI); conventional resin composite Filtek Z350 XT (Z350); resin glass ionomer cement Riva light Cure (RIVA) and flowable resin composite Filtek Bulk Fill Flow (BULK-F) were evaluated. Sixty specimens (n=10) were prepared for sorption (SR), solubility (SL), flexural strength (FS), shrinkage stress (SS), conversion degree (CD), microhardness (MI), and surface roughness (SR) tests. Non-cured and light-cured materials were assessed on FTIR. 30 human molar teeth were used in the bond strength test (BS). Data were subjected to ANOVA and post-hoc Tukey's test (5% of significance). EQUI showed more sorption in SR and no statistical difference from RIVA and CN-LC. CN group showed more solubility and EQUI presented less (p<0.05). BULK-F showed higher FS (MPa), without differences from CN and Z350, whereas EQUI presented the lowest FS not differing from RIVA. BULK-F and CN-LC showed more shrinkage stress differing from EQUI. CN-LC and CN showed higher CD differing from the other which showed no differences (p>0.05) between them. EQUI showed the highest hardness (p<0.05) in MI. There were no differences (p>0.05) in SR (µm). Z350 and BULK-F presented higher BS, whereas CN-LC showed the lowest, although not differing from EQUI and RIVA. Equia Forte's solubility and microhardness make it a good alternative as a restorative material. Cention N degree of conversion and flexural strength making it an esthetic option to amalgam.

Resumo Este estudo analisou as propriedades físico-químicas dos materiais de ionômero bioativo. Os materiais bioativos Cention N quimicamente ativados (CN) e fotopolimerizados (CN-LC), Equia Forte Fill (EQUI); resina composta convencional Filtek Z350 XT (Z350); resina de ionômero de vidro Riva light Cure (RIVA) e resina composta fluida Filtek Bulk Fill Flow (BULK-F) foram avaliados. Sessenta espécimes (n=10) foram preparados para testes de sorção (SR), solubilidade (SL), resistência à flexão (FS), tensão de contração (SS), grau de conversão (CD), microdureza (MI) e rugosidade da superfície (SR). Os materiais não curados e curados com luz foram avaliados por FTIR. 30 dentes molares humanos foram usados no teste de resistência de união (BS). Os dados foram submetidos a ANOVA e teste de post-hoc Tukey (5% de significância). O EQUI apresentou maior sorção no SR e não mostrou diferença estatística em relação aos grupos RIVA e CN-LC. O grupo CN apresentou maior solubilidade e o EQUI apresentou menor (p<0,05). O BULK-F apresentou maior FS (MPa), sem diferir do CN e do Z350, enquanto o EQUI apresentou o menor FS, não diferindo do RIVA. O BULK-F e o CN-LC apresentaram maior estresse de contração, diferindo do EQUI. O CN-LC e o CN apresentaram maior CD (%), diferindo dos demais, que não apresentaram diferenças (p>0,05) entre si. A EQUI apresentou a maior dureza (p<0,05) no MI. Não houve diferenças (p>0,05) na SR (µm). Z350 and BULK-F apresentaram BS, enquanto a CN-LC apresentou a menor, embora não diferindo da EQUI e da RIVA. A solubilidade e a microdureza do Equia Forte o tornam uma boa alternativa como material restaurador. O grau de conversão e a resistência à flexão do Cention N o tornam uma opção estética ao amálgama.

High risk factors in images for infiltrating lung adenocarcinoma manifesting as peripheral ground-glass nodules / 中国胸心血管外科临床杂志

@#Objective     To explore the correlation between the imaging features of peripheral ground-glass pulmonary nodules and the invasion degree of lung adenocarcinoma, and the high risk factors for infiltrating lung adenocarcinoma under thin-slice CT, which provides some reference for clinicians to plan the surgical methods of pulmonary nodules before operation and to better communicate with patients, and assists in building a clinical predictive model for invasive adenocarcinoma. Methods    Clinical data of the patients with peripheral ground-glass pulmonary nodules (diameter≤3 cm) in thin-slice chest CT in the First Affiliated Hospital of Soochow University from January 2019 to January 2020 were continuously collected. All patients underwent thin-slice CT scan and thoracoscopic surgery in our center. According to the pathological examination results, they were divided into two groups: an adenocarcinoma lesions before infiltration group, and an invasive lung adenocarcinoma group. The thin-slice CT imaging parameters of pulmonary nodules were collected. The nodular diameter, mean CT value, consolidation tumor ratio (CTR), nodular shape, vacuolar sign, bronchial air sign, lobulation sign, burr sign, lesion boundary, pleural depression sign, vascular cluster sign and other clinical data were collected. Univariate and multivariate analyses were conducted to analyze the independent risk factors for the infiltrating lung adenocarcinoma, and to analyze the threshold value and efficacy of each factor for the identification of infiltrating lung adenocarcinoma. Results     Finally 190 patients were enrolled. There were 110 patients in the adenocarcinoma lesions before infiltration group, including 21 males and 89 females with a mean age of 53.57±10.90 years, and 80 patients in the invasive lung adenocarcinoma group, including 31 males and 49 females with a mean age of 56.45±11.30 years. There was a statistical difference in the mean CT value, nodular diameter, CTR, gender, smoking, nodular type, nodular shape, vacuolar sign, lobulation sign, burr sign, lesion boundary, pleural depression sign, vascular cluster sign between the two groups (P<0.05). However, there was no statistical difference between the two groups in age (P=0.081), lesion site (P=0.675), and bronchial air sign (P=0.051). Multiple logistic regression analysis showed that nodular diameter, mean CT value, CTR and lobulation sign were independent risk factors for differentiating preinvasive adenocarcinoma from invasive adenocarcinoma. At the same time, the threshold value was calculated by Youden index, indicating that the CTR was 0.45, the nodal diameter was 10.5 mm and the mean CT value was –452 Hu. Conclusion     In the peripheral ground-glass pulmonary nodules, according to the patient's CT imaging features, such as mixed ground-glass nodules, irregular shapes, vacuoles, short burrs, clear boundaries, pleural indentations, and vascular clusters, have a certain reference value in the discrimination of the invasion degree of ground-glass pulmonary nodules. At the same time, it is found in this research that peripheral ground-glass pulmonary nodules with diameter greater than 10.5 mm, CT value greater than –452 Hu, CTR greater than 0.45 and lobulation sign are more likely to be infiltrating lung adenocarcinoma.

Invasiveness assessment by CT quantitative and qualitative features of lung cancers manifesting ground-glass nodules in 555 patients: A retrospective cohort study / 中国胸心血管外科临床杂志

@#Objective     To explore the correlation between the quantitative and qualitative features of CT images and the invasiveness of pulmonary ground-glass nodules, providing reference value for preoperative planning of patients with ground-glass nodules. Methods    The patients with ground-glass nodules who underwent surgical treatment and were diagnosed with pulmonary adenocarcinoma from September 2020 to July 2022 at the Third Affiliated Hospital of Kunming Medical University were collected. Based on the pathological diagnosis results, they were divided into two groups: a non-invasive adenocarcinoma group with in situ and minimally invasive adenocarcinoma, and an invasive adenocarcinoma group. Imaging features were collected, and a univariate logistic regression analysis was conducted on the clinical and imaging data of the patients. Variables with statistical difference were selected for multivariate logistic regression analysis to establish a predictive model of invasive adenocarcinoma based on independent risk factors. Finally, the sensitivity and specificity were calculated based on the Youden index. Results     A total of 555 patients were collected. The were 310 patients in the non-invasive adenocarcinoma group, including 235 females and 75 males, with a meadian age of 49 (43, 58) years, and 245 patients in the invasive adenocarcinoma group, including 163 females and 82 males, with a meadian age of 53 (46, 61) years. The binary logistic regression analysis showed that the maximum diameter (OR=4.707, 95%CI 2.060 to 10.758), consolidation/tumor ratio (CTR, OR=1.027, 95%CI 1.011 to 1.043), maximum CT value (OR=1.025, 95%CI 1.004 to 1.047), mean CT value (OR=1.035, 95%CI 1.008 to 1.063), spiculation sign (OR=2.055, 95%CI 1.148 to 3.679), and vascular convergence sign (OR=2.508, 95%CI 1.345 to 4.676) were independent risk factors for the occurrence of invasive adenocarcinoma (P<0.05). Based on the independent predictive factors, a predictive model of invasive adenocarcinoma was constructed. The formula for the model prediction was: Logit(P)=–1.293+1.549×maximum diameter of lesion+0.026×CTR+0.025×maximum CT value+0.034×mean CT value+0.72×spiculation sign+0.919×vascular convergence sign. The area under the receiver operating characteristic curve of the model was 0.910 (95%CI 0.885 to 0.934), indicating that the model had good discrimination ability. The calibration curve showed that the predictive model had good calibration, and the decision analysis curve showed that the model had good clinical utility. Conclusion     The predictive model combining quantitative and qualitative features of CT has a good predictive ability for the invasiveness of ground-glass nodules. Its predictive performance is higher than any single indicator.

Clinical application of lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture in the restoration of single anterior tooth loss / 口腔疾病防治

Objective@#To investigate the clinical effect of lithium disilicate glass ceramic cantilever resin-bonded fixed partial dentures (CRBFPDs) on single anterior tooth loss to provide a reference for the selection of restoration methods for single anterior tooth loss.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-two patients with less than two anterior teeth with monomaxillary loss were included in this study. After 6 months, 1 year, 2 years, and 3 years, the aesthetic and functional effects of the restorations and the periodontal health status were evaluated, and the visual analog scale (VAS) was used to assess patient satisfaction.@*Results@#During the observation period, the connector fractured in one case within 3 months. One case had debonded within 2 years. The aesthetic restoration effect of all lithium disilicate glass ceramic CRBFPDs was categorized as Class A. The periodontal health was good, there was no clinical absorption in the soft and hard tissues of the abutment or subbridge, periodontal status according to the evaluation indices was classified as class A, and the total satisfaction rate of the patient was 100%.@*Conclusion@#For single anterior tooth loss patients, lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture can achieve the restoration effect of less invasion, better adhesion, aesthetics, comfort and good biocompatibility. With high patient satisfaction, it can be considered an ideal restoration method for replacing a single anterior tooth.

Insertion methods and gap/void formation in atraumatic restorative technique: A micro-CT analysis

Abstract Wetting the dentin is critical to atraumatic restorative treatment. The conventional insertion can be challenging when using high-viscosity glass-ionomer cement. This study evaluated the formation of gaps and voids after three insertion methods using micro-CT. Teeth underwent removal of occlusal and proximal caries through the atraumatic restorative treatment technique. Then, they were fixed in an artificial dental arch to simulate the clinical condition and were restored using three insertion methods: conventional, Centrix injection, and double-filling. Previous dentin conditioning procedures, steel matrix and wooden wedge application, and post-insertion procedures (digital compression and surface protection) were the same. The material was inserted using a manual instrument in the conventional technique and was inserted with a syringe in the Centrix injection group. In the double-filling technique, the tooth received a first layer of a flowable ionomer (through modifying the powder/liquid ratio), and a second layer (with standard ratio) was applied before the final set of the first one. A micro-CT unit scanned each tooth before and after restoration. Each cavity was defined as the volume of interest, and the volumes of gaps and voids were calculated. Data were analyzed using one-way ANOVA and Tukey posthoc test (p < .05). Double-filling had improved filling volume with lower values for gap volume, followed by Centrix injection. The conventional technique had the highest gap volume. No statistically significant difference was observed for void volume. Double-filling demonstrated fewer gaps, followed by Centrix injection, which is critical to obtain better adhesive, remineralizing, and antibacterial activities.

Resumo O molhamento da dentina parcialmente desmineralizada no fundo da cavidade dentária é fundamental para o sucesso do tratamento restaurador atraumático. No entanto, o método de inserção convencional pode ser desafiador ao usar cimento de ionômero de vidro de alta viscosidade. Este estudo avaliou a formação de gaps e vazios internos após três métodos de inserção de cimento de ionômero de vidro de alta viscosidade usando micro-CT. Dez terceiros molares foram submetidos à remoção de cárie oclusal através da técnica de tratamento restaurador atraumático e complementação proximal (com ou sem lesão pré-existente). Em seguida, foram fixados em uma arcada dentária artificial para simular a condição clínica. Os dentes foram restaurados usando a técnica de tratamento restaurador atraumático com três métodos de inserção: convencional, injeção Centrix e dupla inserção. Os procedimentos anteriores de condicionamento dentinário, inserção de matriz de aço, aplicação de cunha de madeira e procedimentos pós-inserção do material (como compressão digital e proteção de superfície) foram os mesmos para os três grupos testados. O material foi inserido com instrumento manual na técnica convencional, seguindo a metodologia clássica do tratamento restaurador atraumático. O material foi inserido com um dispositivo desenvolvido especificamente para esse fim na técnica de inserção com seringa tipo Centrix. Na técnica de dupla obturação, o dente recebeu uma primeira camada do cimento de ionômero de vidro mais fluido (obtido através da modificação da relação pó/líquido), e uma segunda camada (com relação pó/líquido padrão) foi aplicada antes da presa final da primeira. Um micro-CT escaneou cada dente antes e depois da restauração. Cada cavidade foi definida como o volume de interesse, e os volumes de gaps e vazios foram calculados. Os dados foram analisados por ANOVA one-way e teste post-hoc de Tukey com nível de significância de 5%. A dupla inserção melhorou significativamente o volume de preenchimento com valores percentuais mais baixos para o volume do gap, seguido pela injeção com seringa tipo Centrix. A técnica convencional apresentou o maior percentual de volume de gap. Nenhuma diferença estatisticamente significativa foi observada para o volume de vazios internos. O grupo de dupla inserção demonstrou menor formação de gaps, seguido pelo grupo de injeção com seringa tipo Centrix, que é fundamental para obter melhores atividades adesivas, remineralizantes e antibacterianas.

Effect of sodium/calcium hypochlorite on adhesion and adaptation of fiber posts luted with a dual resin cement

Abstract This study aimed to evaluate the effect of different concentrations of sodium hypochlorite (NaOCl) and calcium hypochlorite [Ca(OCl)2] on the bond strength and adaptation of glass fiber posts luted with a dual-curing resin cement. Fifty decoronated premolars were sectioned 14 mm from the apex and endodontically treated. The root canal filling was partially removed. The specimens were divided into 5 groups (n=10) according to the irrigant for post space irrigation: 0.9% sodium chloride (NaCl), (control); 2.5% NaOCl; 5.25% NaOCl; 2.5% Ca(OCl)2; and 5.25% Ca(OCl)2. For each group, irrigation was performed with 5 ml of solution. Afterward, the posts were luted with a dual-curing resin cement. One slice from each third was obtained and submitted to the push-out test and failure modes analysis. An additional slice from the middle third was submitted to confocal images for analysis of adaptation failures (gaps). Two-way ANOVA, Tukey's post-hoc, Kruskal-Wallis with Bonferroni adjusted, and chi-square tests, analyzed data. The group treated with 5.25% NaOCl showed lower bond strength values and generated more cohesive failures compared to the control (p < 0.05). Bond strength decreased from coronal to apical in the post space (p < 0.001). The groups treated with NaOCl had the highest percentages of gaps compared to the control (p < 0.05). Regardless of concentration, Ca(OCl)2 did not influence the bond strength and the occurrence of gaps (P > 0.05). Ca(OCl)2 is a good option for irrigating the post space before luting a fiber post with a dual-curing resin cement.

Resumo Este estudo teve como objetivo avaliar o efeito de diferentes concentrações de hipoclorito de sódio (NaOCl) e hipoclorito de cálcio [Ca(OCl)2] na resistência de união e adaptação de pinos de fibra de vidro cimentados com um cimento resinoso dual. Cinquenta pré-molares tiveram suas coroas removidas, foram seccionados a 14 mm do ápice e tratados endodonticamente. A obturação do canal radicular foi parcialmente removida. Os espécimes foram divididos em 5 grupos (n=10) de acordo com o irrigante para irrigação do espaço do pino: cloreto de sódio 0.9% (NaCl), (controle); NaOCl 2.5%; NaOCl 5.25%; Ca(OCl)2 2.5%; e Ca(OCl)2 5.25%. Para cada grupo, a irrigação foi realizada com 5 ml da solução. Posteriormente, os pinos foram cimentados com um cimento resinoso dual. Uma fatia de cada terço foi obtida e submetida ao teste push-out e análise dos modos de falha. Um corte adicional do terço médio foi submetido a imagens confocais para análise de falhas de adaptação (gaps). Os dados foram analisados pelos testes ANOVA de duas vias, post-hoc de Tukey, Kruskal-Wallis com ajuste de Bonferroni e qui-quadrado. O grupo tratado com NaOCl 5.25% apresentou menores valores de resistência de união e gerou mais falhas coesivas em relação ao controle (p < 0.05). A resistência de união diminuiu de coronal para apical no espaço do pino (p < 0.001). Os grupos tratados com NaOCl apresentaram os maiores percentuais de gaps em relação ao controle (p < 0.05). Independentemente da concentração, o Ca(OCl)2 não influenciou a resistência de união e a ocorrência de gaps (P > 0.05). O Ca(OCl)2 é uma boa opção para irrigar o espaço do pino antes de cimentar um pino de fibra com um cimento resinoso dual.

Distribution-and-analysis-of-chest-radiographic-findings-in-covid19-positive-symptomatic-and-asymptomatic-patients—analysis-of-668-patients-in-india

Current COVID-19 radiological literature is dominated by CT and a detailed description of chest x-ray (CXR) appearances in relation to the disease time course is lacking. However, it poses a great challenge on the radiology department, as it is difficult to decontaminate entire CT suite(Zhao et al., 2020)11. This study is aimed to correlate clinical symptoms with the chest X-ray findings in COVID positive patients and to calculate the sensitivity and specificity of chest x ray in diagnosing COVID 19. The present study compares frequency and distribution of chest radiographic findings in COVID 19 positive symptomatic and asymptomatic patients. Patients with a RT-PCR-positive results for COVID 19 infection were 668. Of these, 437 were males (65.4%), 230 females (34.4%) and 1 transgender (0.04%) with a mean age of 44 years (range 2–87 years). Only 18 CXRs were negative for radiological thoracic involvement (6.4%) among symptomatic patients (280). Among the baseline CXR of 668 patients, 375 (56.1%) were normal and 293 (43.8%) were abnormal. Sensitivity and specificity of CXR were 93.91% and 93.3% respectively. Positive and negative predictive values were 90.97% and 95.51% respectively. We found a statistically significant relationship between CXR severity score and age, symptoms, death (P<0.001).We even found significant relationship between age and symptoms, death of COVID positive patients (P<0.001). The relationship between CXR severity and gender, age and gender were not significant (P=0.539, P=0.864 respectively)

Comparison of Fracture Resistance of Simulated Immature Teeth Using Four Different Commercially Available Apexification Materials ? An invitro Study

Introduction: The aim of this study was to compare the fracture resistance of simulated immature teeth using four different apical plug materials, i.e. Pro? Root MTA, Neo? MTA Plus, Biodentine, and Bioactive Glass. Materials and Methods: 80 extracted human maxillary anterior teeth were divided into 4 groups for this study. They were prepared using Peeso reamers to simulate immature teeth and to mimic Cvek’s stage 3 of root development. A 5 mm apical barrier was placed using different materials. The remaining canal was obturated using gutta?percha and AH plus sealer. The final samples were stored at 37°C and 100% humidity for 4 weeks. Fracture resistance of the teeth was measured in Newtons using a universal testing machine. The comparison of fracture resistance between the four groups was done using Kruskal Walis ANOVA followed by post hoc Mann Whitney U test for pairwise comparison. Results: Biodentine group showed the highest fracture resistance as compared to the other three groups and the difference was highly significant (P < 0.001). Conclusions: Biodentine can be advocated over MTA as an effective material for the management of teeth with wide open apex. Bioactive glass also has shown promising results in increasing the fracture resistance of simulated immature teeth.

Comparison of Fracture Resistance of Endodontically Treated Teeth Restored with Different Aesthetic Post and Core Systems Under All Ceramic Restoration Luted with Two Types of Cements

Context: Fracture of endodontically treated teeth is a grave sequela that a clinician should seriously ponder. Suitable selection of restorative materials is a requisite for long?term clinical success. Aims: To compare the fracture resistance of endodontically treated teeth restored with three different posts luted using two different cements under all ceramic crowns. Settings and Design: This in vitro study was conducted in the Department of Prosthodontics, Government Dental College, Kottayam, Kerala, India. Methods and Material: Thirty endodontically treated single?rooted mandibular premolars in which post spaces were prepared and divided into three different groups. Group 1 (n = 10): zirconia post group. Group 2 (n = 10): quartz fibre post group. Group 3 (n = 10): glass fibre post group. Each group is sub?divided into two based on the luting system: resin?modified glass ionomer cement (RMGIC) or dual?cure resin cement (DCRC). The fracture resistance testing was performed in a universal testing machine with a crosshead speed of 0.5 mm/min. Statistical Analysis Used: The mean fracture resistance were analysed using independent sample Student t?test and one?way ANOVA. Results: Within the zirconia post group, the mean fracture resistance was higher in DCRC sub?group compared to the RMGIC sub?group and the difference was statistically significant (p = 0.017). The difference in fracture resistance between three different post systems was not found to be statistically significant with respect to both the luting systems. Conclusions: It was observed that when zirconia post is used, the mean fracture resistance was higher in dual?cure resin group compared to the resin?modified GIC group.

The effect of Phytosphingosine and bioactive glass-ceramics in preventing dental enamel erosion

Abstract This study evaluated the effect of phytosphingosine (PHS) and bioactive glass-ceramic (Biosilicate) on dental enamel in terms of color alteration (ΔE), microhardness, and surface roughness when submitted to erosive challenge (EC). Sixty specimens of bovine teeth (6×6×2mm) were obtained. Initial color (Easyshade, VITA), KHN (HMV-2, Shimadzu), and Ra (SJ-201P, Mitutoyo) measurements were performed. Specimens were separated into groups according to treatments: PHS, 10% Biosilicate, PHS+10% Biosilicate, and artificial saliva (control) and submitted to EC with Coca-Cola for 2 min. This cycle was repeated 4 times daily/15 days. Between cycles, specimens remained in artificial saliva (2 h/37°C). After daily cycles, they were also stored in artificial saliva at 37ºC. Final color, microhardness, and surface roughness measurements were done. Color and KHN data were analyzed by one-way ANOVA, Tukey's test; and Ra, by 2-way ANOVA, repeated measures, and Tukey's test (p<.05). The highest ΔE occurred in Saliva+EC (p<.05). Groups treated with PHS presented lower color change than Saliva+EC (p<.05). All the groups presented mean values above the 50:50% perceptibility (50:50%PT) and acceptability (50:50%AT) thresholds, except for control that showed mean value above 50:50%PT but below 50:50%AT. Biosilicate+EC showed higher relative microhardness than Saliva+EC (p<.05), but was similar to PHS+EC and PHS+Biosilicate+EC. Final enamel surface roughness increased for all the groups (p<.05), except for the control. The Biosilicate may prevent enamel mineral loss induced by erosion better than saliva. The PHS associated or not to Biosilicate demonstrated better color stability than saliva.

Resumo Este estudo avaliou o efeito da Fitoesfingosina (PHS) e da vitrocerâmica bioativa (Biosilicato) sobre o esmalte dental em termos de alteração de cor (ΔE), microdureza (KHN) e rugosidade superficial, quando submetido a desafio erosivo (DE). Sessenta espécimes de dentes bovinos (6×6×2mm) foram obtidos. Foram realizadas leituras de cor inicial (Easyshade, VITA), microdureza (HMV-2, Shimadzu) e rugosidade superfícial (SJ-201P, Mitutoyo). Os espécimes foram separados em grupos de acordo com os tratamentos: PHS, Biosilicato a 10%, PHS+Biosilicato a 10%, e saliva artificial (controle). Em seguida, foram submetidos a DE com Coca-Cola por 2 min. Esse ciclo foi repetido 4 vezes/dia por 15 dias. Entre os ciclos, as amostras foram mantidas em saliva artificial (2 h/37°C). Após os ciclos diários, os espécimes também foram armazenados em saliva artificial a 37ºC. Foram realizadas leituras finais de cor, microdureza e rugosidade superficial. Os dados de cor e microdureza foram analisados ​​por ANOVA de uma via, teste de Tukey; e dados de rugosidade superficial, por ANOVA de duas vias, teste de Tukey (p<.05). A maior ΔE ocorreu em Saliva+DE (p<.05). Grupos tratados com PHS apresentaram menor alteração de cor do que Saliva+DE (p<.05). Biosilicate+DE demonstrou valores intermediários, similar (p>.05) aos outros grupos, exceto Saliva+DE. Todos os grupos presentaram média acima dos limites 50:50% de perceptibilidade (50:50%LP) e aceitabilidade (50:50%LA) exceto o controle que demonstrou média acima do 50:50%LA mas abaixo do 50:50%LP. Biosilicate+DE mostrou maior microdureza realativa do que Saliva+DE (p<.05), mas similar a PHS+DE e PHS+Biosilicato+DE. A rugosidade de superfície do esmalte aumentou para todos os grupos, exceto para o controle que presentou a menor alteração (p<.05). O Biosilicato apode prevenir perda mineral do esmalte indizido pela erosão melhor que a saliva. O PHS associado ou não ao Biosilicato demonstrou melhor estabilidade de cor que a saliva.

Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Resumo Avaliar o efeito do envelhecimento e sistemas de cimentação usando ionômero de vidro e cimentos resinosos na resistência de união à dentina após a cimentação do pino de fibra. Cento e vinte incisivos bovinos foram utilizados. Após o preparo do pós-espaço, os corpos de prova foram distribuídos aleatoriamente em 12 grupos (n = 10) de acordo com o período de envelhecimento (24 horas, 6 meses e 12 meses) e o sistema de cimentação utilizado: GC - cimento de ionômero de vidro (GC Gold Label Cimentação e Revestimento); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200. Cortes dos terços cervical, médio e apical foram obtidos e analisados por teste de resistência de união push-out e microscopia confocal de varredura a laser. ANOVA one-way e teste de Tukey foi usado a um nível de significância de 5%. Para o teste de resistência de união, não foram observadas diferenças entre GC, RU e MC nos terços cervical e médio, independentemente do período de armazenamento (P > 0,05). No terço apical, GC e RU apresentaram resistência de união semelhante, porém superior aos demais grupos (P > 0,05). Após 12 meses, o GC apresentou a maior resistência de união (P < 0,05). A resistência de união à dentina no espaço para pino diminuiu ao longo do tempo, independentemente do sistema de cimentação utilizado. A formação de tags foi semelhante entre todos os grupos. Após 12 meses, o GC apresentou os maiores valores de resistência de união.

The predictive value of CT signs of mixed ground-glass nodules in pathological subtypes and differentiation of lung adenocarcinoma / 中国胸心血管外科临床杂志

@#Objective    To explore the predictive value of CT signs of mixed ground-glass nodules in the pathological subtype and differentiation of lung adenocarcinoma. Methods    The clinical data of 66 patients with mixed ground-glass nodules pathologically diagnosed as invasive adenocarcinoma (IAC) in the Second Department of Thoracic Surgery, the First Affiliated Hospital of Xiamen University from May to December 2021 were retrospectively analyzed, including 20 males and 46 females, aged 35-75 years. The CT findings were analyzed before operation, and the lesion profile was cut after operation to distinguish the ground-glass and solid components, and the pathological results of different positions were obtained. According to the postoperative pathological results, the patients were divided into a low-risk group (containing adherent type and no components of micropapillary subtype and solid subtype, n=16), a medium-risk group (containing niple or acinar type and no components of micropapillary subtype and solid subtype, n=38), and a high-risk group (containing micropapillary or solid subtype, n=12). The relationships between CT features and the pathological subtype and degree of differentiation were analyzed and compared. Results    In 66 patients with IAC, the infiltration degree of solid components was greater than that of ground-glass components. When the solid component ratio (CTR) was≥25% (sensitivity 90.2%, specificity 64.0%, P=0.005), and the average CT value was>−283.95 HU (sensitivity 82.9%, specificity 64.0%, P=0.000), the histological grade was more inclined to medium and low differentiation. The CTR, Ki-67, average CT value and histological grade of IAC in the medium- and high-risk groups were higher than those of nodules in the low-risk group. Conclusion    The infiltration degree of solid components is higher than that of ground-glass components in IAC mixed ground-glass nodules. The pathological subtype, Ki-67 expression and histological grade of lung adenocarcinoma can be predicted according to its CT characteristics, which has important clinical significance for determining the timing of surgery.

Research progress on fluoride-releasing restorative materials for caries control / 口腔疾病防治

@#Restorative materials such as conventional glass ionomer cement (CGIC), resin-modified glass ionomer cement (RMGIC), polyacid-modified composite resin (compomer), and giomer have the properties of fluoride release and refill, which may prevent or slow down the progression of caries. The caries resistance of these materials was evaluated according to the following criteria: fluorine-releasing ability, antibacterial activity, mechanical properties and anti-aging properties. The anti-caries effect of these materials mainly depends on the effect of fluoride ions on mineralization. However, materials with strong fluorine release ability, such as CGIC, are mainly used in pediatric dentistry and temporary restoration due to their poor mechanical properties. It is difficult to achieve both fluoride ion release potential and mechanical strength, and there are few materials that can provide ideal mechanical strength while maintaining a high standard of fluoride release. The fluoride releasing and recharging capacity of CGIC, RMGIC, compomer and giomer decrease successively. The trend of material modification, to a certain extent, tends to sacrifice the fluoride release capacity of materials to maintain the ideal mechanical strength. In recent years, scholars have tried to add a variety of fillers to further enhance the anti-cracking ability of materials and add antibacterial agents to compensate for the anti-caries effect to reduce the loss of fluoride release.

Establishment and Verification of Benign and Malignant Prediction Model of Subcentimeter Pulmonary Ground Glass Nodules Based on HRCT / 中国肺癌杂志

BACKGROUND@#Pre-operative accuracy of subcentimeter ground glass nodules (SGGNs) is a difficult problem in clinical practice, but there are few clinical studies on the benign and malignant prediction model of SGGNs. The aim of this study was to help identify benign and malignant lesions of SGGNs based on the imaging features of high resolution computed tomography (HRCT) and the general clinical data of patients, and to build a risk prediction model.@*METHODS@#This study retrospectively analyzed the clinical data of 483 patients with SGGNs who underwent surgical resection and were confirmed by histology from the First Affiliated Hospital of University of Science and Technology of China from August 2020 to December 2021. The patients were divided into the training set (n=338) and the validation set (n=145) according to 7:3 random assignment. According to the postoperative histology, they were divided into adenocarcinoma group and benign lesion group. The independent risk factors and models were analyzed by univariate analysis and multivariate Logistic regression. The receiver operator characteristic (ROC) curve was constructed to evaluate the model differentiation, and the calibration curve was used to evaluate the model consistency. The clinical application value of the decision curve analysis (DCA) evaluation model was drawn, and the validation set data was substituted for external verification.@*RESULTS@#Multivariate Logistic analysis screened out patients' age, vascular sign, lobular sign, nodule volume and mean-CT value as independent risk factors for SGGNs. Based on the results of multivariate analysis, Nomogram prediction model was constructed, and the area under ROC curve was 0.836 (95%CI: 0.794-0.879). The critical value corresponding to the maximum approximate entry index was 0.483. The sensitivity was 76.6%, and the specificity was 80.1%. The positive predictive value was 86.5%, and the negative predictive value was 68.7%. The benign and malignant risk of SGGNs predicted by the calibration curve was highly consistent with the actual occurrence risk after sampling 1,000 times using Bootstrap method. DCA showed that patients showed a positive net benefit when the predictive probability of the predicted model probability was 0.2 to 0.9.@*CONCLUSIONS@#Based on preoperative medical history and preoperative HRCT examination indicators, the benign and malignant risk prediction model of SGGNs was established to have good predictive efficacy and clinical application value. The visualization of Nomogram can help to screen out high-risk groups of SGGNs, providing support for clinical decision-making.

Growth Regularity of Pulmonary Ground Glass Nodules Based on 3D Reconstruction Technology / 中国肺癌杂志

BACKGROUND@#Since the popularization of computed tomography (CT) technology, the detection rate of pulmonary ground glass nodules (GGNs) with imaging follow-up as the main management method has increased significantly. The purpose of this study is to quantitatively analyze the changes of pulmonary GGNs during the follow-up process with three-dimensional reconstruction technology, explore the natural progression of pulmonary GGNs, and provide effective basis for clinical guidance for patients to conduct reasonable management of nodules.@*METHODS@#A total of 115 cases of pulmonary GGNs with regular follow-up in the Combined Outpatient Department of Zhoushan Hospital from March 2015 to November 2022 were enrolled. Quantitative imaging features of nodules were extracted by semi-automatic segmentation of 3D Slicer software to evaluate the growth of nodules and clinical intervention during follow-up.@*RESULTS@#The average baseline age of the patients was (56.9±10.1) yr. The mean follow-up time was (48.8±18.9) months. The two-dimensional diameter of baseline CT scan was (7.9±2.9) mm, and the maximum three-dimensional diameter was (10.1±3.4) mm. The two-dimensional diameter of the last CT scan was (9.9±4.7) mm, and the maximum three-dimensional diameter was (11.4±5.1) mm. A total of 27 cases (23.5%) showed an increase during follow-up, with a median volume doubling time of 822 days and a median mass doubling time of 1,007 days. 32 cases were surgically resected, including 6 cases of invasive adenocarcinoma (IAC), 16 cases of minimally invasive adenocarcinoma (MIA), 8 cases of adenocarcinoma in situ (AIS) and 2 cases of atypical adenomatous hyperplasia (AAH). Five nodules underwent surgical intervention due to the progression of two-dimensional diameter, which was pathologically confirmed as pre-invasive lesions, but their three-dimensional maximum diameter showed no significant change. Nodular morphology, lobulated sign, spiculated sign and vacuole signs all promoted the growth of nodules in univariate analysis. There were significant differences in age, baseline diameter, mean CT value, median CT value, 10% and 90% percentile CT number between the growth group and the stable group (P<0.05). Multivariate Logistic regression analysis showed that age and average CT value were risk factors for nodule growth (P<0.05). Receiver-operating characteristic (ROC) curve analysis results indicated that the age ≥63 years old, the baseline three-dimensional maximum diameter ≥9.2 mm, and the average CT value ≥-507.8 HU were more likely to accelerate the growth of GGNs. The maximum three-dimensional diameter ≥14.4 mm and the average CT value ≥-495.7 HU may be a higher malignant probability.@*CONCLUSIONS@#GGNs show an inert growth process, and the use of three-dimensional measurements during follow-up is of greater significance. For persistent glass grinding nodules ≥63 years old, the baseline three-dimensional maximum diameter ≥9.2 mm, and the average CT value ≥-507.8 HU are more likely to increase. However, most nodules still have good prognosis after progression, and long-term follow-up is safe.

Effects of novel bioactive glasses on promoting remineralization of artificial dentin caries / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of novel bioactive glasses (BG) including PSC with high phosphorus component and FBG with fluorine-doped element on promoting remineralization of artificial dentin caries.@*METHODS@#(1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.@*RESULTS@#(1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.@*CONCLUSION@#PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.

Influence of paper mixing pads thickness on the compressive strength of glass ionomer cement / 北京大学学报(医学版)

OBJECTIVE@#To explore the influence of the thickness of mixed cardboard on the compressive strength of glass ionomer cement and the associated factors.@*METHODS@#Three different types of glass ionomer cements were mixed on the top of 60, 40, 20 and 1 pieces of paper (P60, P40, P20 and P1), respectively. The compressive strength of the materials was tested after solidification, and the bubble rate was calculated with the assistance of scanning electron microscope.@*RESULTS@#(1) Compressive strength: ① ChemFil Superior glass ionomer (CF): The average compressive strength of P1 group was the highest, which was significantly different from that of P40 and P60 groups (P values were 0.041 and 0.032 respectively); ② To Fuji IX GP glass ionomer (IX): The average compressive strength of P1 group was the highest, which was statistically different from that of P40 and P60 groups (P values were 0.042 and 0.038 respectively); ③ Glaslonomer FX-Ⅱ glass ionomer cement (FX): The average compressive strength of P1 group was the highest, which was statistically different from that of P20, P40 and P60 groups (P values were 0.031, 0.040 and 0.041 respectively), but there was no statistical difference among the other groups. All the three materials showed that the compressive strength of glass ions gradually increased with the decrease of the thickness of the blended paperboard, and the two materials had a highly linear negative correlation, the correlation coefficients of which were CF-0.927, IX-0.989, FX-0.892, respectively. (2) Scanning electron microscope: P1 group had the least bubbles among the three materials.@*CONCLUSION@#It indicates that the thickness of mixed cardboard has a negative correlation with the compressive strength of glass ions. The thicker the mixed cardboard is, the greater the elasticity is. Excessive elasticity will accelerate the mixing speed when the grinding glass ions. Studies have shown that the faster the speed of artificial mixing is, the more bubbles is produced.The thicker ther mixed cardboard is, the more bubblesn are generated by glass ionomer cement, and the higher the compressive strength is. Using one piece of paper board to mix glass ionomer cement has the least bubbles and can obtain higher compressive strength.

Prediction of Lymph Node Metastasis of Mixed Ground-glass Nodules Based on Clinical Imaging Information / 中国肺癌杂志

BACKGROUND@#Previous studies have shown that lymph node metastasis only occurs in some mixed ground-glass nodules (mGGNs) which the pathological results were invasive adenocarcinoma (IAC). However, the presence of lymph node metastasis leads to the upgrading of tumor-node-metastasis (TNM) stage and worse prognosis of the patients, so it is important to perform the necessary evaluation before surgery to guide the operation method of lymph node. The aim of this study was to find suitable clinical and radiological indicators to distinguish whether mGGNs with pathology as IAC is accompanied by lymph node metastasis, and to construct a prediction model for lymph node metastasis.@*METHODS@#From January 2014 to October 2019, the patients with resected IAC appearing as mGGNs in computed tomography (CT) scan were reviewed. All the lesions were divided into two groups (with lymph node metastasis or not) according to their lymph node status. Lasso regression model analysis by applying R software was used to evaluate the relationship between clinical and radiological parameters and lymph node metastasis of mGGNs.@*RESULTS@#A total of 883 mGGNs patients were enroled in this study, among which, 12 (1.36%) showed lymph node metastasis. Lasso regression model analysis of clinical imaging information in mGGNs with lymph node metastasis showed that previous history of malignancy, mean density, mean density of solid components, burr sign and percentage of solid components were informative. Prediction model for lymph node metastasis in mGGNs was developed based on the results of Lasso regression model with area under curve=0.899.@*CONCLUSIONS@#Clinical information combined with CT imaging information can predict lymph node metastasis in mGGNs.