• Restorative Dentistry and Endodontics
• /
• v.48 no.1
• /
• pp.1.1-1.11
• /
• 2023

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

• Journal of the Korean Home Economics Association
• /
• v.39 no.7
• /
• pp.125-144
• /
• 2001

The purpose of this study is to make a preliminary investigation about the diagnostic process for marital preparation against future divorce which will be necessary for developing tools for the process. Delphi tests have been twice held among 23 professionals regarding the concept of marital diagnosis and the areas of marital preparation to be estimated including definitions of the marital preparation for marriage and the status in which marriage has been prepared, and the categorization of the preparation The result of the study is as follows : Firstly, the concept of marital preparation is comprehensive, for it does include various kinds of preparation necessary for adjustment to marital life except the preparation for wedding ceremony. Secondly, the status in which marriage has been prepared can be divided into individual preparation, a couple's relational preparation, and preparation for marital life. Thirdly, premarital preparation education or counselling will be provided for young persons who are not in status of marital preparation. The areas of marital preparation to be estimated are maturity, independence from parents, and good health in terms of individual preparation, and the depth of love, understanding each other, similarity, harmonization, supplementation, capacity of communication, self-control, and all that sort of thing in terms of relational preparation, sex, views about marriage, information about marital life, role division, giving birth to child and rearing, financial management, and understanding both families of husband and wife.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.9
• /
• pp.827-832
• /
• 2005

Dual band internal antennas were fabricated with Ag conducting paste of various preparation conditions and different print thickness by silk screen print. We have investigated microwave properties were compared Ag conducting paste antenna with copperplate antenna at 800 MHz and 1,800 MHz. Gain of Ag conducting paste antenna was improved when preparation conditions were the single size Ag particle, using dry type resin and high Ag containing percent. However, it was lower than that of copperplate antenna within $0.1\~2.0dBi$ at 800MHz. In addition, it was improved at 800MHz when thickness of Ag conducting paste was printed more than skin depth but it was held after critical print thickness. On the other hand, it was reached level of copperplate antenna at 1,800MHz.

• Journal of Periodontal and Implant Science
• /
• v.39 no.1
• /
• pp.53-58
• /
• 2009

Purpose: The resective treatment in mandibular Degree III furcation areas includes root resection and tunnel preparation. The purpose of this retrospective study is to evaluate which treatment procedure(root resection vs tunnel preparation) has more favorable prognosis in mandibular Degree III furcation involvement. Materials and methods: The subjects of this study were patients who were treated their mandibular posteriors with either root resection(22 teeth on 22 patients) or tunnel preparation(24 teeth on 22 patients) and have participated in periodic recall check program for at least 2 years. Failure rate, plaque index, bleeding on probing and probing pocket depth were measured and the results were compared and statistically analysed. Results: Failure rates of root resection and tunnel praparation were 13.6% and 16.7%, respectively, and showed no significant difference between two procedures. No significant differences were observed between two procedures with respect to plaque index, bleeding on probing and probing pocket depth. Conclusion: root resection and tunnel preparation are both effective procedures to treat mandibular posterior furcation involvement, if adequate treatment of choice is made and patient's cooperation is accompanied. However, tunnel preparation is more preservative procedure in mandibular posterior furcation involvement since root canal treatment and prosthetic restoration are needed additionally, in case of root resection.

• Mycobiology
• /
• v.47 no.4
• /
• pp.483-493
• /
• 2019

Antrodia cinnamomea is a unique medicinal fungus in Taiwan. It has been found rich in some pharmacologically active compounds for anti-cancer, hangover, and immune regulation etc. With the in-depth study of these components, it would be interesting and important to establish a molecular system for basic studies of A. cinnamomea. Thus, we would like to set up a foundation for this purpose by studying the A. cinnamomea protoplast preparation and regeneration. Firstly, we studied the optimization method of protoplast preparation of A. cinnamomea, and found various factors that may affect the yield during protoplast preparation, such as mycelial ages, pH values, and osmotic stabilizers. Secondly, in the regeneration of protoplasts, we explored the effects of various conditions on the regeneration of protoplasts, including different media and osmotic pressure. In addition, we found that citrate buffer with pH value around 3 dramatically increased the regeneration of protoplasts of A. cinnamomea, and provided a set of regeneration methodology for A. cinnamomea.

• Journal of Korean Elementary Science Education
• /
• v.35 no.2
• /
• pp.205-215
• /
• 2016

This study aims to investigate how elementary teachers use teachers' guide in preparation for science lessons. First, different uses of teacher's guide were analyzed. Second, how and why teachers use each section in teacher's guide were analyzed. For the study, 24 elementary school teachers were interviewed in depth. The semi-structured in-depth interviews were conducted individually and/or in small group, and additional interviews were held when necessary. The results showed that most of the teachers used teacher's guide only substitutionally, and some teachers rarely use teacher's guide, while only 3 out of 24 teachers used teacher's guide in detail. The reasons that teachers used the teacher's guide substitutionally or rarely were that most science lessons include experiments, and science textbook itself provides enough information for preparation of science lessons for 3rd and 4th grade students. The results also revealed that only few teachers read the general guideline in teacher's guide. Some sections of teacher's guide were not used. The sections that many teachers used were the aims of lesson, the learning system of the unit, background knowledge, flow of lesson, learning contents and activities. This study specifically examined the actual use of teacher's guide for lesson preparation and discussed implications for the development of more helpful teacher's guide.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.3
• /
• pp.227-235
• /
• 2018

PURPOSE. Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped. MATERIALS AND METHODS. Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral. RESULTS. Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. CONCLUSION. The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

• The Journal of Advanced Prosthodontics
• /
• v.7 no.3
• /
• pp.183-190
• /
• 2015

PURPOSE. This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. MATERIALS AND METHODS. Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a $4.5{\times}10$ mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: $5-55^{\circ}C$, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. RESULTS. The fracture loads were $539.28{\pm}63.11$ N (N5), $406.56{\pm}28.94$ N (N7), $366.66{\pm}30.19$ N (N9), $392.61{\pm}50.57$ N (A5), $317.94{\pm}30.05$ N (A7), and $292.74{\pm}37.15$ N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). CONCLUSION. The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.

• Restorative Dentistry and Endodontics
• /
• v.8 no.1
• /
• pp.161-166
• /
• 1982

The purpose of this study was to examine the influence of canal preparation on the property of apical seal. Seventy canals from extracted human maxillary and mandibular teeth were randomly selected and divided into two groups: conventional group and step-back group. Thirty five canals in one group were enlarged with a, conventional preparation method and thirty five canals in the other group were instrumented in a step-back method with K-file. After instrumentation sixty canals were obturated by lateral condensation of gutta percha and zinc oxide eugenol cement, and five canals in each group were not filled and used as control. All the specimens were immersed in 2% methylene blue dye solution and the depth of dye penetration into the canals were observed by macroscope at the intervals of 1 day, 2 days, and 7 days. The following results were obtained. 1. All the canals experimented showed varying degrees of dye penetration. 2. There was no significant difference between conventional method and step-back method in the depth of dye penetration and the degree of dye penetration tended to increase with time passage in both groups. 3, In conventional preparation group the mean dye penetration was 3.6mm at 1 day, 4.8mm at 2 days. and 6.5mm at 7 days. 4. In step-back prepareation group, the specimens exposed to the dye for 1 day showed mean dye penetration of 4.1mm, and the specimens immersed in the dye for 2 days and 7 days revealed mean dye penetration of 4.6mm and 6.2mm respectively.

• Journal of Periodontal and Implant Science
• /
• v.40 no.5
• /
• pp.239-243
• /
• 2010

Purpose: The purpose of this study was to evaluate the effects of implant shape and bone preparation on the primary stability of the implants using resonance frequency analysis. Methods: Sixty bovine rib blocks were used for soft and hard bone models. Each rib block received two types of dental implant fixtures; a straight-screw type and tapered-screw type. Final drilling was done at three different depths for each implant type; 1 mm under-preparation, standard preparation, and 1 mm over-preparation. Immediately after fixture insertion, the implant stability quotient (ISQ) was measured for each implant. Results: Regardless of the bone type, the ISQ values of the straight-screw type and tapered-screw type implants were not significantly different (P>0.05). Depth of bone preparation had no significant effect on the ISQ value of straight-screw type implants (P>0.05). For the tapered-screw type implants, under-preparation significantly increased the ISQ value (P<0.05), whereas overpreparation significantly decreased the ISQ value (P<0.05). Conclusions: Within the limitations of this study, it is concluded that bone density seemed to have a prevailing effect over implant shape on primary stability. The primary stability of the tapered-screw type implants might be enhanced by delicate surgical techniques.