• The Journal of Korean Academy of Prosthodontics
• /
• v.53 no.4
• /
• pp.352-358
• /
• 2015

The retention of complete dentures in patients with Parkinson's disease is often poor due to their constant dislodgement by involuntary movements of the tongue and lips. Furthermore, insertion of the overdenture is expected to be difficult due to their limited voluntary movements. This case is about the bimaxillary overdenture restoration where its retention and stability are improved, using magnetic attachment of remained roots of maxilla and two implant $Locator^{(R)}$ attachments of mandible in patients with Parkinson's disease. This report describes the fabrication of this functionally improved prosthesis.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.28 no.2
• /
• pp.139-145
• /
• 2012

The purpose of this study was to evaluate the accuracy of Root ZX and Sybron Mini in determining the working length using 2.5% Sodium Hypochlorite, 2% Chlorhexidine gel and saline. Donnelly's gelatin technique was used for measuring twenty extracted human teeth. Electronic working length was measured at the display 0.5 and 0.0 level of each electronic apex locator using a digital caliper to the nearest 0.01 mm. Each measurement was repeated for each different irrigants. Accuracy of Sybron Mini was not significantly different from the Root ZX in the three different irrigants, and there was no significant difference in the accuracy of electronic apex locators among the irrigants when used as recommended by manufacturer (measuring electronic working length at 0.0 level of Sybron Mini and at 0.5 level of Root ZX).

• Journal of the Korean Society for Railway
• /
• v.20 no.5
• /
• pp.595-601
• /
• 2017

Due to the electrification of railways, fault at the traction line is increasing year by year. So importance of the fault locator is growing higher. Nevertheless at the field traction line, it is difficult to locate accurate fault point due to various conditions. In this paper railway feeding system current loop equation was simplified and generalized though measured data. And substation, train power data were measured under synchronized condition. Finally catenary impedance was predicted through generalized equation. Also simulation model was designed to figure out the effect of load current for train at same location. Train current was changed from min to max range and catenary impedance was compared at same location. Finally, power measurement was performed in the field at train and substation simultaneously and catenary system impedance was predicted and calculated. Through this method catenary impedance can be measured more easily and continuously compared to the past method.

• Restorative Dentistry and Endodontics
• /
• v.40 no.1
• /
• pp.44-49
• /
• 2015

Objectives: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. Materials and Methods: Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. Results: The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of ${\pm}1.0mm$ (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for ${\pm}0.5mm$; r = -0.940 for ${\pm}1.0mm$). Conclusions: The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.514-521
• /
• 2018

COSPAS-SARSAT 406 MHz emergency beacons include ELTs for aviation, EPIRBs for maritime, and PLBs for individuals in distress. They are used to sending messages encoded on 406 MHzdistress frequency and sending alertsfor search and rescue in distress. C/S T.001 and T.018 are COSPAS-SARSAT technical documents. They include basic technical information needed for developing beacons, howmessages are constructed, and test methods for type approval. COSPAS-SARSAT systems that use existing low earth orbit (LEO) and geostationary earth orbit (GEO) satellites do not have a return link service (RLS). So, the survivors could not confirm whether the distress signal was sending or not. However, a new medium earth orbit (MEO)satellite system has been added to thissystem, allowing confirmation through the RLS function. This paper analyzed C/S T.001 and T.018 needed to develop navigation structuresthat incorporated improved PLB of 406 MHz, a homing signal generator of 121.5 MHz, and a VHF AM transmitter for aviation of 243 MHz.

• The Journal of Korean Academy of Prosthodontics
• /
• v.57 no.1
• /
• pp.42-48
• /
• 2019

In the case of a patient with a small number of unilateral remaining teeth in the mandible, a restoration with conventional removable partial denture cannot provide sufficient retention and resistance. A harmful stress from the poor stability of denture on remaining teeth occurs due to alveolar bone resorption in edentulous area. Although implant fixed prosthesis can provide multiple benefits over conventional removable partial denture, there are limitations come from anatomic structures and costs. In this case, an implant-assisted removable partial denture (IARPD) with a couple of implants placed in strategic positions can be a treatment modality. The objective of this article is to present a case report of two patients showed satisfactory clinical outcomes during three-year follow-up period describing the fabrication and advantages of removable partial denture assisted by teeth and implants (IARPD) for a patient with a small number of unilateral remaining teeth in mandible using Locator as an implant attachment.

• Journal of Periodontal and Implant Science
• /
• v.53 no.3
• /
• pp.194-206
• /
• 2023

Purpose: A novel attachment system for implant-retained overdentures (IRODs) with novel material combinations for improved mechanical resilience and prosthodontic success (Novaloc) has been recently introduced as an alternative to an existing system (Locator). This study investigated whether differences between the Novaloc and Locator attachment systems translate into differences in implant survival, implant success, and patient-centered outcomes when applied in a real-world in-practice comparative setting in patients restored with mandibular IRODs supported by 2 interforaminal implants (2-IRODs). Methods: This prospective, intra-subject crossover comparison compared 20 patients who received 2 intra-foraminal bone level tapered implants restored with full acrylic overdentures using either the Locator or Novaloc attachment system. After 6 months of function, the attachment in the corresponding dentures was switched, and the definitive attachment system type was delivered based on the patient's preference after 12 months. For the definitive attachment system, implant survival was evaluated after 24 months. The primary outcomes of this study were oral health-related quality of life and patient preferences related to prosthetic and implant survival. Secondary outcomes included implant survival rate and success, prosthetic survival, perceived general health, and patient satisfaction. Results: Patient-centered outcomes and patient preferences between attachment systems were comparable, with relatively high overall patient satisfaction levels for both attachment systems. No difference in the prosthetic survival rate between study groups was detected. The implant survival rate over the follow-up period after 24 months in both groups was 100%. Conclusions: The results of this in-practice comparison indicate that both attachment systems represent comparable candidates for the prosthodontic retention of 2-IRODs. Both systems showed high rates of patient satisfaction and implant survival. The influence of material combinations of the retentive system on treatment outcomes between the tested systems remains inconclusive and requires further investigations.

• Journal of Biomedical Engineering Research
• /
• v.19 no.6
• /
• pp.595-602
• /
• 1998

Among the apex locators, the frequency dependent type is more accurate and convenient to use than others, But the accuracy of the apex locator is still influenced by the presence of various electrolytes used in root canal treatments. In this study, we have developed a frequency dependent electronic apex locator minimizing the influence of the electrolytes on the measurement of root canal lengths. It was also confirmed that two frequencies of 500Hz and 100kHz are optimal for the measuring impedance compare with commercial product used(400Hz and 8kHz)a and there were no differences in accuracy among the three different types of the waveforms; sinusoidal, triangular, and rectangular waves(p>0.05). Impedance ratio of the two different frequencies represents the position of the file in root canal, and the voltage difference of two signals represents the status of the fluid in the root canal. As a result of compensation using the voltage differences, the errors were decreased on the average from +0.54mm to +0.18mm in $H_2O_2$ solution (p<0.01), and from -0.33mm to -0.01mm in NaOCl solution(p<0.01). The accuracies based on ${\pm}$0.5mm, in $H_2O_2$ and NaOCl solutions were improved with the automatic compensation from 71.1% and 91.1% to 82.2% and 100% respectively.

• The Bulletin of The Korean Astronomical Society
• /
• v.31 no.1
• /
• pp.26.2-26.2
• /
• 2006

• The Bulletin of The Korean Astronomical Society
• /
• v.33 no.1
• /
• pp.42.1-42.1
• /
• 2008