The use of different adhesive filling material and mass combinations to restore class II cavities under loading and shrinkage effects: a 3D-FEA

3D tooth models were virtually restored: flowable composite resin + bulk-fill composite (A), glass ionomer cement + bulk-fill composite (B) or adhesive + bulk-fill composite (C). Polymerization shrinkage and masticatory loads were simulated. All models exhibited the highest stress concentration at the enamel-restoration interfaces. A and C showed similar pattern with lower magnitude in A in comparison to C. B showed lower stress in dentine and C the highest cusps displacement. The use of glass ionomer cement or flowable composite resin in combination with a bulk-fill composite improved the biomechanical behavior of deep class II MO cavities

The use of different adhesive filling material and mass combinations to restore class II cavities under loading and shrinkage effects: a 3D-FEA

3D tooth models were virtually restored: flowable composite resin + bulk-fill composite (A), glass ionomer cement + bulk-fill composite (B) or adhesive + bulk-fill composite (C). Polymerization shrinkage and masticatory loads were simulated. All models exhibited the highest stress concentration at the enamel–restoration interfaces. A and C showed similar pattern with lower magnitude in A in comparison to C. B showed lower stress in dentine and C the highest cusps displacement. The use of glass ionomer cement or flowable composite resin in combination with a bulk-fill composite improved the biomechanical behavior of deep class II MO cavities

Bulk filling of Class II cavities with a dual-cure composite: effect of curing mode and enamel etching on marginal adaptation

Objectives: This study attempted to find a simple adhesive restorative technique for class I and II cavities on posterior teeth. Study Design: The tested materials were a self-etching adhesive (Parabond, Coltène/Whaledent) and a dual-cure composite (Paracore, Coltène/Whaledent) used in bulk to restore the cavities. Class II MO cavities were performed and assigned to 4 groups depending on the orthophosphoric acid (H 3 PO 4 ) conditioning of enamel and polymerization method used (chemical or dual). Specimens were subjected to quantitative marginal analysis before and after thermo-mechanical loading. Results: Higher percentages of marginal adaptation at the total margin length, both before and after thermo-mechanical loading, were found in groups in which enamel was etched with phosphoric acid, without significant differences between the chemically and dual-cured modes. The restorations performance was similar on enamel and dentin, obtaining low results of adaptation on occlusal enamel in the groups without enamel etching, the lowest scores were on cervical dentin in the group with no ortophosphoric acid and self-cured. Conclusions: A dual-cure composite applied in bulk on acid etched enamel obtained acceptable marginal adaptation results, and may be an alternative technique for the restoration of class II cavities

Stress analysis of a class II MO-restored tooth using a 3D CT-based finite element model

2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

<原著>歯科保存修復学実習における項目別窩洞形成評価 : 第2報,93年度と94年度との比較について

In 1993, the authors introduced the new educational method that, students evaluate their own prepared cavities according to a criteria-evaluation form in preclinical restorative dentistry, to understand the achievement goalsth at instructors aim at. Then, in 1994, 99 dental undergraduate students (in 1994) evaluated their performance according to the new forms, but the instructors did not discuss or advice in the work. At complet ion for all exercises in the first and second half of preclinical operative dentistry laboratory course, students prepared a right maxillary first molar plastic tooth in a mannequin for Class II MO-sliced casting inlay, and evaluated their own performance according the criteria form. The authors compared the felf-evaluation of the 97 dental students in 1993, and the 99 students in 1994 with the facultys\u27 evaluation of the cavity at the first and second half course. The authors obtained the following results: 1. Student\u27s self-evaluation in 1994 of MO-sliced type inlay cavity preparation were similar to that of the faculty after the first half of the course. But, the evaluation was lower than that 1993. 2. Student\u27s self-evaluation of cavity preparation in 1994 was more similar to that of the faculty than in 1993. But, the evaluation was higher than that of the faculty. 3. Comparing with the instructor\u27s evaluations for the student performance in 1993 with that in 1994, the evaluation in 1994, that in 1994 was lower than in 1993 in both the first and second half of the course

An Evaluation of Milling Ceramic Inlay System, CELAY^[○!R] : Part. 2 Marginal adaptaion and internal fit of CELAY inlay

As the demand for aesthetic restorations has increased in the past few years, tooth color materials have been used frequently in posterior teeth. Ceramics are widely used as dental restorative materials. The CELAY system that creates a ceramic inlay by a milling technique has been developed and introduced recently. The purpose of this study was to investigate the marginal adaptation and internal fit of ceramic inlays made using the CELAY system. Twenty extracted upper premolars were used. Only one clinician prepared all twenty box-shaped class II (MO) cavities to make the cavities uniform. The fabricated ceramic inlay that each of five ceramic inlays made by four clinicians whose clinical experience period differed was luted in the individual cavity with a dual-cured composite resin cement. Then all of them were cut mesio-distally through the center of the inlay. The cut surface of the specimens were observed under a profile projector. Marginal adaptation and internal fit were defined as inter facial distances between a ceramic inlay and cavity wall, and measured at nine preselected points. The following results were obtained; 1) The average gap width for all measured points was 170.2±111.8μm. 2) Statistical analysis showed that there were no significant differences among the nine preselected points. But there were significant differences (P<0.01) among the operators. 3) The fitness of the ceramic inlay to the cavity wall had decreased in the order of the central cavity wall, the margin of the cavity and line angle of the cavity, when compared with the nine measuring points. It may be concluded that if the operator is greatly experienced in the ways of the CELAY system he can reduce operating time and can improve adaptation

Immediate post-treatment crowned Herbst effects in growing patients

OBJECTIVE. The aim of this prospective study was to describe the mechanism of Class II correction in growing patients induced by crown Herbst (cHerbst) appliance as an immediate result of therapy. MATERIALS AND METHODS. Forty patients (mean age 13.6 ± 1.3 years) with stable Class I occlusion 1 year following treatment with the cHerbst appliance were selected from a prospective sample of 180 consecutively treated Class II patients. No other appliances were used during treatment. The immediate dentoskeletal changes after discontinuing cHerbst therapy were compared with a matched sample of untreated Class II subjects (mean age 13.9 ± 1.6 years). Lateral cephalograms were taken before treatment and immediately after one year therapy. RESULTS. Treatment produced significant skeletal changes: increase in mandibular length and SNB angle, decrease of ANB angle, restricted growth of posterior maxilla. Significant dentoalveolar changes: maxillary molars moved backwards and tipped distally, lower first molars moved forward and extruded, lower incisors proclined, upper incisors retroclined, overjet and overbite decreased. CONCLUSIONS. Immediate postreatment results revealed that Class II was mainly corrected due to dentoalveolar changes and only limited skeletal change.publishersversionPeer reviewe

Steatosis drives monocyte-derived macrophage accumulation in human metabolic dysfunction-associated fatty liver disease

BACKGROUND & AIMS: Metabolic dysfunction-associated fatty liver disease (MAFLD) is a common complication of obesity with a hallmark feature of hepatic steatosis. Recent data from animal models of MAFLD have demonstrated substantial changes in macrophage composition in the fatty liver. In humans, the relationship between liver macrophage heterogeneity and liver steatosis is less clear. METHODS: Liver tissue from 21 participants was collected at time of bariatric surgery and analysed using flow cytometry, immunofluorescence, and H&E microscopy. Single-cell RNA sequencing was also conducted on a subset of samples (n = 3). Intrahepatic triglyceride content was assessed via MRI and tissue histology. Mouse models of hepatic steatosis were used to investigate observations made from human liver tissue. RESULTS: We observed variable degrees of liver steatosis with minimal fibrosis in our participants. Single-cell RNA sequencing revealed four macrophage clusters that exist in the human fatty liver encompassing Kupffer cells and monocyte-derived macrophages (MdMs). The genes expressed in these macrophage subsets were similar to those observed in mouse models of MAFLD. Hepatic CD14 CONCLUSIONS: The human liver in MAFLD contains macrophage subsets that align well with those that appear in mouse models of fatty liver disease. Recruited myeloid cells correlate well with the degree of liver steatosis in humans. MdMs appear to participate in lipid uptake during early stages of MALFD. IMPACT AND IMPLICATIONS: Metabolic dysfunction associated fatty liver disease (MAFLD) is extremely common; however, the early inflammatory responses that occur in human disease are not well understood. In this study, we investigated macrophage heterogeneity in human livers during early MAFLD and demonstrated that similar shifts in macrophage subsets occur in human disease that are similar to those seen in preclinical models. These findings are important as they establish a translational link between mouse and human models of disease, which is important for the development and testing of new therapeutic approaches for MAFLD