Search

This study aimed to investigate the accuracy of automatic tooth finish line registration compared to manual registration with regard to various finish line configurations and dental computer-aided design (CAD) software.Finish line registrations were performed on 15 digital tooth models with different finish line configurations (edge roundness radius = 0 mm, 0.2 mm, and 0.4 mm; edge angle = 30°, 60°, 90°, 120°, and 150°) using automatic and manual methods for designing virtual copings (N = 150). The discrepancies between the registered finish line extracted from the copings and the actual finish line segmented from the digitized tooth model were measured. Three-way analysis of variance (ANOVA) and post-hoc analyses with Bonferroni correction (α = 0.05) were used to analyze the results.The finish line configurations, registration methods, and CAD software interacted with the accuracy of the registered finish line (p = 0.001). The automatic finish line registration method exhibited larger error values than the manual method, especially at high finish line edge roundness and obtuse edge angles for both EXOCAD and R2CAD software (p0.001). The difference in dental CAD software affected the registration accuracy in the automatic method (p0.001), but not in the manual method (p = 0.676).Finish line registration errors may occur when the automatic registration method is applied to the indistinct edge of tooth preparation. The accuracy of the automatic finish line registration could differ according to the CAD software program.

The articulator is a prerequisite device for the analysis of occlusion and prosthodontic treatment, and it is required to simulate patient jaw movements. This article describes the technique to obtain sagittal condylar inclination (SCI) using cone beam computed tomography (CBCT) data and intraoral scan of the protrusive interocclusal position. The SCI can be used on a virtual articulator in a computer-aided design software, and it can assist in the fabrication of prosthesis which is harmonious with the mandibular movement of individual patient.

Background: Despite a recent preventive evidence of Lactobacillus and Pediococcus on non-alcoholic fatty liver disease (NAFLD) progression, the underlying mechanistic is less understood. We explored the causality of L. lactis and P. pentosaceus on the gut-metabolomic modulation in the prevention of NAFLD progression in mouse model and subsequently discovered metabolic biomarkers based on NAFLD patients.Results: Six-week-old male C57BL/6J mice were divided into 4 groups (control, Western diet [WD], and 2 WD with strains [L. lactis and P. pentosaceus]). Given completely reproduced data (liver/body ratio, pathology, and metagenomic profiles), comorbid etiologies including inflammation and diabetes were significantly amended by 2 strains. The comprehensive metabolomic profiles of the mouse cecum revealed unique compositional characteristic according to the groups. L. lactis and P. pentosaceus supplementation restored the dysregulation in short chain fatty acids (SCFAs), bile acids, and tryptophan metabolites. Indole derivatives (indole-3-acetic acid, indole-3-propionic acid, and indole-3-acrylic acid) showed anti-inflammatory activities by suppressing pro-inflammation cytokines. Human data (healthy control [n=30] and NAFLD patients [n=74]) were analyzed for clinical association and biomarker. The Fermicutes/Bacteroidetes ratio of NAFLD (4.3) was significantly higher compared with control (0.6)(pConclusion: L. lactis and P. pentosaceus ameliorate NAFLD by modulating gut metabolic environment, particularly the indole pathway, of the gut-liver axis. NAFLD progression was associated with metabolic deterioration in the SCFAs, bile acid, and indole pathways. ClinicalTrials.gov: NCT04339725

Metabolic syndrome (MS) refers to a clustering of at least three of the following medical conditions: high blood pressure, abdominal obesity, hyperglycemia, low high-density lipoprotein level, and high serum triglycerides. MS is related to a wide range of diseases which includes obesity, diabetes, insulin resistance, cardiovascular disease, dyslipidemia, or non-alcoholic fatty liver disease. There remains an ongoing need for improved treatment strategies for MS. The most important risk factors are dietary pattern, genetics, old age, lack of exercise, disrupted biology, medication usage, and excessive alcohol consumption, but pathophysiology of MS has not been completely identified. Korean Red Ginseng (KRG) refers to steamed/dried ginseng, traditionally associated with beneficial effects such as anti-inflammation, anti-fatigue, anti-obesity, anti-oxidant, and anti-cancer effects. KRG has been often used in traditional medicine to treat multiple metabolic conditions. This paper summarizes the effects of KRG in MS and related diseases such as obesity, cardiovascular disease, insulin resistance, diabetes, dyslipidemia, or non-alcoholic fatty liver disease based on experimental research and clinical studies., Graphical abstract Image 1

The aim of this study was to determine the stability of computer-aided design and manufacturing (CAD/CAM) and prefabricated abutment by measuring removal torque before and after cyclic loading.Three types of fixture and 2 types of abutments were used. Removable torque was measured after cyclic loading for 5000 cycles between 25 and 250 N for each group. The same procedure was performed twice.First, removal torque values (Newton centimeter) were measured for stock versus custom abutments as follows: group 1: 27.17 versus 26.67, group 2: 26.27 versus 26.33, and group 3: 37.33 versus 36.67. Second removal torque values (Newton centimeter) were also measured: group 1: 23 versus 23.5, group 2: 22.5 versus 22.33, and group 3: 32.67 versus 32.5. There was no significant difference between the stock and custom abutments in either the first or second removal torque values and also no significant difference among initial tightening torque, first or second removal torque (P0.05).With precise control of CAD/CAM abutments, good screw joint stability can be achieved.

Motor fault is a major problem in unmanned oriented systems such as smart factories. Recently, some studies have been actively carried out to make such a fault diagnosis unattended by a deep learning algorithm. However, these studies do not take into account the speed at which motors are driven, and therefore they are not appropriate for the actual system. In this paper, the experiment was performed to develop a deep learning algorithm that considered the motor speed. The method is that regard the vibration signal as an image and uses the algorithm, CNN, which is suitable for this processing. Adopting the suitable model reduced over-fitting and increased accuracy by reducing the model complexity. As a result, it is shown that fault diagnosis can be performed considering the motor driving speed by using the deep learning algorithm.

The conventional method for impressions of flabby tissue uses modified trays and highly flowable materials, but mucostatic impressions are difficult to achieve due to the viscous and the elastic natures of impression materials. In this report, a technique is presented in which conventional impression and intraoral scanning for a fully edentulous patient with flabby tissue are combined. The definitive impression was obtained by applying appropriate pressure to each tissue area, and the denture can be maintained passively and stable at rest and during function.

With the rapid development of wireless communication at VHF and UHF bands, there is an increasing need for the reliable propagation prediction tools. Therefore, the different propagation models that have been developed in many countries as well as korea has been trying to secure a model suitable for their geographical area but then it is giving us a different result when we compared it to measured values. In this paper, based on the measurements of DTV broadcasting services in domestic urban area, analysis and comparison of ITU-R P.1546 and BCAST models provide errors between measured and predicted values, and some points for improving SMI system has been proposed. As a result, P.1546 model provides the valid predicted data similar to measured data, but BCAST model has some problems of large deviation and higher prediction to measured data. In future, these problems and diffractions due to high buildings need to be studied further.

Evaluating the cement space of various dental prostheses is important because it is related to the stability and retention of the prosthesis. However, a method for evaluating an overall cement space is complex. The purpose of this technique was to simplify the evaluation of prosthesis cement space by using a digital scanner. The form and thickness of the cement space could be simply recognized in any section the clinician or dental researcher wishes. Moreover, the cement space of several dental prostheses for the same abutment could also be precisely evaluated by superimposition. The method can be applied to various prosthodontic treatments.

Panfacial fractures involve trauma to the lower, middle, and upper facial bones and often require a team approach for management. Early and complete restoration of preinjury facial contours and function should be the goal of the oral and maxillofacial surgeon and the prosthodontist. When the intraoral landmarks are lost, overall facial anatomic landmarks can be used to restore the oral cavity. A patient with complex clinical panfacial fractures, including a vertically and horizontally malpositioned native alveolar bone and severe facial asymmetry, is presented. A functional and esthetic rehabilitation was successfully accomplished by using a partial removable dental prosthesis retained with telescopic crowns and magnetic attachments in the maxilla and osseointegrated implants to support a definitive dental prosthesis in the mandible.

Novel porous poly(L-lactide) (PLLA) scaffolds with surface-immobilized nano-hydroxyapatite (N-HAp) were synthesized for effective bone regeneration. N-Hap-bearing surface phosphate functionalities were immobilized chemically on the pore surface of amine-treated PLLA scaffolds. Thermogravimetric analysis (TGA) showed that 24 wt% of N-HAp had been immobilized on the scaffold pore surface. Field-emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) confirmed that N-HAp was exposed markedly on the pore surfaces of scaffolds compared to the conventional scaffold fabricated by a bulk-mixing process of PLLA and N-HAp. The PLLA scaffold with surface-immobilized N-HAp had a higher surface Ca atomic ratio (4.6%) than that on the pore surface of the bulk-mixed PLLA/N-HAp scaffold (Ca = 0.4%). The porous PLLA scaffolds with surface-immobilized N-HAp provided favorable environments for enhanced in vivo bone tissue growth, which was estimated by hematoxylin and eosin (H&E) staining for organic bone tissues and alizarin red S staining for inorganic bone minerals. These results suggest that the N-HAp immobilization approach may produce many useful scaffolds with pore surfaces featuring excellent bone tissue-regenerative properties.

가철성 국소의치의 금속구조물을 제작하는 방법은 왁스 패턴을 제작하여 주조하는 lost wax technique이 주로 사용되어 왔으나, 디지털 기술의 발달로 서베잉과 금속구조물을 CAD (Computer aided design)로 디자인하여 제작할 수 있게 되었다. 여러 증례에서 CAD를 이용한 pattern의 프린팅 방식으로 얻은 레진 패턴이 구...

As an effort to expand their applicability of both room temperature ionic liquid (RTIL) and single-walled carbon nanotube (SWNT), we prepared a gel-like paste using imidazolium-based ionic liquid (1-n-butyl-3-methylimidazolium tetrafluoroborate; [Bmim] BF 4 ) and SWNT, and investigated their internal structure and viscoelastic characteristics. The suspension containing 1 wt% of SWNT was prepared via grinding it in an agate mortar. A black paste (gel) was then obtained from its centrifugation. Rheological properties of a purified SWNT- ionic liquid ([Bmim] BF 4 ) gel were measured using a rotational rheometer equipped with a parallel plate geometry, and then compared with those of unpurified SWNT-ionic liquid gel from both steady shear and oscillatory shear mode tests. We also examined their effects of a well-dispersed SWNT in a suspending medium on rheological properties, resulting in gel-state even at a very low filler concentration due to the nano-dimension of SWNT and its interaction with a novel ionic liquid. From this study, it is found that the characteristic rheological behaviors, such as high shear thinning, dynamic yield stress, and frequency independent dynamic behavior, not only support the gel formation due to the uniform dispersion of SWNT in the ionic liquid medium, but also explain the formation of network structure induced by a strong interaction between ionic liquid and SWNT. In addition, we also observed that such a gel structure was followed by a shear induced secondary structure in a high shear rate region.

Feldspathic porcelain paste system using organic vehicle was prepared and applied to fabricate the porcelain fused to metal fixed partial denture. The mean linear fired shrinkage of paste porcelain system was 15.2% that is 0.8% lower than that of conventional build-up method. The color difference between two methods (􀁕E*) was 0.156. Mean biaxial flexural strength of sintered preformed laminating porcelains of this system and conventionally build-up porcelains were 74±3 and 70±4 MPa respectively. There was no deterioration of physical properties of feldspathic porcelain system by introducing organic vehicle, and this new build-up method can be applied to fabricate the porcelain fused to metal restorations.

목적: 이 연구의 목적은 coloring agent의 종류와 적용 횟수가 지르코니아의 색조에 미치는 영향을 알아보는 것이다. 재료 및 방법: 단일구조 지르코니아( $15.7mm{\times}15.7mm{\times}2.0mm$ )를 준비하여 완성된 시편은 11개 실험군 그룹으로 coloring agent의 종류와 적용 횟수에 따라 a1-a5와 w1-w5로 나누었다. 색...

With conventional fixed dental prostheses, the interim restoration is a valuable diagnostic tool in the evaluation of esthetics and function. To achieve predictable definitive esthetic results, information about the subgingival and the supragingival contour of a properly designed restoration should be communicated to the dental laboratory technician. The technique described enables the accurate transfer of the soft tissue morphology developed with an interim prosthesis to the definitive cast. This modified definitive cast allows the dental laboratory technician to fabricate a restoration with an emergence profile identical to that of the interim prosthesis.

Implant has been an effective treatment option for the patients with oligodontia. However, it still remains unclear when the implant should be placed. Skeletal growth that can appear even after the growth period can lead to infraocclusion of the implant which can cause functional or esthetic complications. In order to minimize these problems, definitive restorations should be placed after the functional and esthetic rehabilitation is achieved through the use of provisional restorations. Definitive restorations made with monolithic zirconia were created by replicating provisional restorations by using the latest CAD/CAM technology. These definitive restorations were delivered to the patient and clinical observation after the treatment showed satisfactory result. (J Korean Acad Prosthodont 2016;54:28-34)

In removable dental prostheses, it is important to minimize impairment of residual tissue caused by wearing dentures. There are two factors that harm residual tissue. The first is functional load bearing of remaining teeth and alveolar ridges and the second is the effect of poor oral hygiene. Double crown retained removable dental prostheses provide rigid support, and it may reduce impairment caused by load bearing of alveolar ridges. Also, dental plaque and oral deposits, which are attached to outer crowns and dentures, can be easily managed extra-orally. In addition, it is beneficial to the health of the marginal gingiva because inner crowns have easy access for oral hygiene. In this case, double crown retained removable dental prostheses were used for the partially edentulous patient with severe residual alveolar bone resorption and poor oral hygiene, and the result was clinically satisfactory in terms of functional, esthetical, and oral hygiene aspects. (J Korean Acad Prosthodont 2016;54:21-7)

The aim of this study was to analyze and compare the level and distribution of peri-implant bone stresses associated with mandibular two-implant overdentures with different implant positions.Mathematical models of mandibles and overdentures were designed using finite element analysis software. Two intraosseous implants and ball attachment systems were placed in the interforaminal region. The overdenture, which was supported by the two implants, was designed to withstand bilateral and unilateral vertical masticatory loads (total 100 N). In all, eight types of models, which differed according to assigned implant positions, height of attachments, and angulation, were tested: MI (model with implants positioned in the lateral incisor sites), MC (implants in canine sites), MP (implants in premolar sites), MI-Hi (greater height of attachments), MC-M (canine implants placed with mesial inclination), MC-D (canine implants placed with distal inclination), MC-B (canine implants placed with buccal inclination), and MC-L (canine implants placed with lingual inclination).Peri-implant bone stress levels associated with overdentures retained by lateral incisor implants resulted in the lowest stress levels and the highest efficiency in distributing peri-implant stress. MI-Hi showed increased stress levels and decreased efficiency in stress distribution. As the implants were inclined, stress levels increased and the efficiency of stress distribution decreased. Among the inclined models, MC-B showed the lowest stress level and best efficiency in stress distribution.The lowest stress and the best stability of implants in mandibular two-implant overdentures were obtained when implants were inserted in lateral incisor areas with shorter attachments and were placed parallel to the long axes of the teeth.

The purpose of this study was to investigate the cellular activities of MG63 osteoblast-like cells on modified titanium surfaces.MG63 osteoblast-like cells were cultured on titanium disks (n = 20 in each group) with turned, resorbable blast media (RBM)-treated, or anodized surfaces. The surfaces of commercially available implants of Osstem (Osstem Implant) were reproduced for the titanium disks. The morphology of cells cultured on these disks was examined using scanning electron microscopy. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. Specimens were also evaluated with an initial cell adhesion assay to compare initial adhesion, with a methyl tetrazol sulfate (MTS) assay to compare the proliferation ability, and with an alkaline phosphatase (ALP) assay to compare the differentiation ability. Statistical significance of the differences was determined using the Kruskal-Wallis test for the cell adhesion assay and analysis of variance for the MTS and ALP assays.Attached cells with more defined lamellopodia and flattened morphology were observed on the anodized and RBM surfaces than on the turned surfaces. The titanium surfaces were all oxidized as titanium oxide and polluted by carbon determinants, as determined by XPS. Anodized titanium surfaces exhibited calcium and phosphorus peaks. Initial cell attachment activity, cell proliferation activity, and ALP activity were higher on the anodized surfaces than on the other surfaces. Cell differentiation on the anodized surfaces at culture day 10 was significantly higher (P.05) than on the other surfaces.Surface treatment by anodization may improve initial attachment of cells, proliferation ability, and differentiation activity, which play important roles in providing better osseointegration of implants. More rapid and stronger osseointegration of implants may make it possible to offer the best anchorage and shorten the healing time required prior to functional loading.

Ectodermal dysplasia is a hereditary disorder of ectodermal origin. A 12-year-old boy was referred for management of the oral manifestations of his ectodermal dysplasia. An overdenture retained by natural teeth for the maxilla and a double-crown-retained denture for the mandible were made. Double-crown-retained dentures may be modified into complete dentures if the abutment teeth are lost. The patient was instructed to maintain oral hygiene and return periodically for follow-up visits. This report describes a potential routine approach to restoring the appearance, function, and psyche of a growing boy with ectodermal dysplasia.