The effect of sandblasting duration on the bond durability of dual-cure adhesive cement to CAD/CAM resin restoratives

Neslihan Tekçe,Safa Tuncer,Mustafa Demirci 대한치과보철학회 2018 The Journal of Advanced Prosthodontics Vol.10 No.3

PURPOSE. To evaluate the effect of prolonged sandblasting on the bond durability of dual-cure adhesive resin cement to computer-aided design and computer-aided manufacturing (CAD/CAM) restoratives. MATERIALS AND METHODS. Nano-ceramic LAVA Ultimate and hybrid-ceramic VITA Enamic CAD/CAM blocks were used for this study. Each CAD/CAM block was sectioned into slabs of 4-mm thickness for the microtensile test (μTBS) test and 2-mm thickness for the surface roughness test. Three groups were created according to the sandblasting protocols; group 1: specimens were sandblasted for 15 seconds, group 2: specimens were sandblasted for 30 seconds, and group 3: specimens were sandblasted for 60 seconds. After sandblasting, all specimens were luted using RelyX Ultimate Clicker. Half the specimens were subjected to μTBS tests at 24 hours, and the other half were subjected to tests after 5000 thermocycles. Additionally, a total of 96 CAD/CAM block sections were prepared for surface roughness tests and scanning electron microscopy (SEM) evaluations. The Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance, and Dunn’s post hoc test were used to compare continuous variables among the groups. RESULTS. At baseline, group 1, group 2, and group 3 exhibited statistically similar μTBS results for LAVA. However, group 3 had significantly lower μTBS values than groups 1 and 2 for VITA. After 5000 thermocycles, μTBS values significantly decreased for each block (P<.05). CONCLUSION. It is important to perform controlled sandblasting because it may affect bond strength results. Sixty seconds of sandblasting disturbs the initial μTBS values and the stability of adhesion of CAD/CAM restoratives to dual-cure adhesive resincement for VITA Enamic.

The effect of different drinks on the color stability of different restorative materials after one month

Neslihan Tekçe,Safa Tuncer,Mustafa Demirci,Merve Efe Serim,Canan Baydemir 대한치과보존학회 2015 Restorative Dentistry & Endodontics Vol.40 No.4

Objectives: The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. Materials and Methods: Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates (L*a*b*, ΔL*, Δa*, Δb*, and ΔE*) were measured using a VİTA Easyshade Compact (VİTA Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (ΔE) were calculated and were analyzed by Kruskal- Wallis and Dunn multiple comparison test. Results: The color difference (ΔE*) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 ± 2.61) and black tea (12.22 ± 2.73) showed the highest mean ΔE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 ± 1.25) and Filtek Ultimate Flowable (4.71 ± 1.40) in black tea (p < 0.05). Conclusions: The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.

基礎圖形 指導의 體系에 對한 一考察 : 國民學校 低學年을 中心으로 for the Lower Grade of Primary Schools

申澤均 대구교육대학교 1968 論文集 Vol.4 No.-

No efforts have ever been made for an understandable system of the basic figure instruction-that is, how and from what point of view the figure materials have to be systematized. With this in mind, my study deals with the figure system for the lower grades of primary schools. On the basis of the results of analyzing the targets and contents of our lower--grade figure instruction and researching the development steps of children's understanding figure, a study on the figure instruction system was made.

유아의 사회적 귀인 성향에 관한 연구

조희숙,윤택원 부산대학교 영유아보육연구소 1997 영유아보육연구 Vol.3 No.-

This study aims first, to examine how young children's social attribution can differ in a successful circumstance or in a failure circumstance according to their gender, and second, to examine the difference between young children's social attribution and perceived young children's social attribution by their own classroom teachers. 123 preschoolers from 4 kindergartens located in Pusan and their 4 teachers participated for this study. The major findings of this study were as follows: First, in a failure circumstance, there was gender difference on young children's social attribution. That is, boys attributed their failure to their inner traits than those of girls. Second, there wasn't any differences between young children's social attribution and perceived young children's social attribution by their own classroom teachers either in the success circumstance or in the failure situation.

Microhybrid versus nanofill composite in combination with a three step etch and rinse adhesive in occlusal cavities: five year results

Safa Tuncer,Mustafa Demirci,Evren Öztaş,Neslihan Tekçe,Ömer Uysal 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.4

Objectives: The aim of the study was to evaluate the 5-year clinical performance of occlusal carious restorations using nanofill and microhybrid composites, in combination with 3-step etch-and-rinse adhesives, in patients who were going to commence orthodontic treatment. Materials and Methods: A total of 118 restorations for occlusal caries were conducted prior to orthodontic treatment. Occlusal restorations were performed both with Filtek Supreme XT (3M ESPE) and Filtek Z250 (3M ESPE) before beginning orthodontic treatment with fixed orthodontic bands. Restorations were clinically evaluated at baseline and at 1, 2, 3, 4, and 5-year recalls. Results: None of the microhybrid (Filtek Z250) and nanofill (Filtek Supreme XT) composite restorations was clinically unacceptable with respect to color match, marginal discoloration, wear or loss of anatomical form, recurrent caries, marginal adaptation, or surface texture. A 100% success rate was recorded for both composite materials. There were no statistically significant differences in any of the clinical evaluation criteria between Filtek Z250 and Filtek Supreme XT restorations for each evaluation period. Conclusions: The composite restorations showed promising clinical results relating to color matching, marginal discoloration, wear or loss of anatomical form, recurrent caries, marginal adaptation, and surface texture at the end of the 5-year evaluation period.

Construction of Expression Vectors for the High Level Expression in Actinomycetes

( Tek Narayan Lamichhane ),( Rajan Lamichhane ),( Hei Chan Lee ),( Kwangkyoung Liou ),( Jae Kyung Sohng ) 한국공업화학회 2003 한국공업화학회 연구논문 초록집 Vol.2003 No.-

Evaluation of dietary quality of adolescents using Healthy Eating Index

Tek, Nilufer Acar,Yildiran, Hilal,Akbulut, Gamze,Bilici, Saniye,Koksal, Eda,Karadag, Makbule Gezmen,Sanher, Nevin The Korean Nutrition Society 2011 Nutrition Research and Practice Vol. No.

The aim of this study was to use the Healthy Eating Index-2005 (HEI-2005) to assess diet quality and determine the relationship between the HEI-2005 and the energy and nutrient intakes of adolescents. A cross-sectional study was conducted on 1,104 healthy adolescents, mean age of $15.8{\pm}1.24$ years. Dietary intake was measured with the 24-hour dietary recall method, and dietary quality was assessed by means of the HEI-2005. Diet quality scores ranged from 23.7 to 77.5. The mean score was found to be $51.5{\pm}9.07$ according to the HEI-2005. There were no differences according to gender, 42.8% had a poor diet and 57.2% had a diet that needs improvement. No subjects had a "good diet". Lower mean subgroup scores were found for whole grains, total vegetables, total fruits, dairy products, and meat and beans. Fruits and vegetables scores were significantly high in girls, whereas sodium, oil, and meat and beans scores were significantly high in boys. Total HEI-2005 scores were increasingly associated with parental education level when age and gender were adjusted. There was a negative correlation between HEI-2005 scores and age, total energy intake, and fat intake. Positive correlation was only observed in the HEI-2005 scores for protein and dietary fibre intakes. Consequently, the overall diet quality and nutritional habits of Turkish adolescents need modification and improvement. In the family, measures should be initiated by the government, including advertisements and campaigns.

Selection of elite broadleaf mustard (Brassica juncea var. rugosa) (L.) germplasms for the mid-hill conditions of Nepal

Tek Prasad Gotame,Surendra Lal Shrestha,Dipendra Ghimire 한국국제농업개발학회 2021 韓國國際農業開發學會誌 Vol.33 No.3

This study was carried out to select the suitable and high leaf yielding broadleaf mustard genotypes for the mid-hill conditions of Nepal. We evaluated seven germplasms of broadleaf mustard (Brassica juncea var. rugosa (L.) Czern.) namely, ‘HRDBLM001’, ‘HRDBLM004’, ‘HRDBLM007’, ‘HRDBLM009’, ‘HRDBLM010’, ‘Marpha Chauda Pat’, and ‘Khumal Chauda Pat’ in the field of the National Horticulture Research Centre, Khumaltar under Nepal Agricultural Research Council during the winter season of two consecutive years, 2019 and 2020. The germplasms were collected from the local diversity centres in the country. The experiment was laid out in the Randomized Complete Block Design (RCBD) in three replications per treatment. Seeding was done in September, and 28-day-old seedlings were transplanted in the field. The results obtained from the two consecutive seasons revealed that plant vigour was found to be greater in ‘HRDBLM010’ and ‘Khumal Chauda Pat’ (4.7 in the 1 to 5 scale score). The highest leaf weight (65.1 g) was found in ‘HRDBLM010’, followed by ‘HRDBLM007’ (45.6 g) and ‘Khumal Chauda Pat’ (40.9 g). The highest number of leaves was produced by ‘HRDBLM004’ (50 leaves per plant), while leaf weight per plant was the highest in ‘HRDBLM010’ (691.1 g per plant) followed by ‘HRDBLM004’ (535.4 g per plant). Genotype ‘HRDBLM010' produced the highest leaf yield (54.52 MT ha-1), followed by 'HRDBLM004' (44.28 MT ha-1) and ‘HRDBLM007’ (41.65 MT ha-1). Thus, these three germplasms showed superiority among the seven tested germplasms and they could be recommended for cultivation in the mid-hill conditions of Nepal.

Hybrid Breeding in Vegetables in Nepal

Tek Prasad Gotame,Ishwori Prasad Gautam,Surendra Lal Shrestha,Navin Gopal Pradhan 한국국제농업개발학회 2021 韓國國際農業開發學會誌 Vol.33 No.4

In Nepal, about 73% of the vegetable production area is estimated to be covered by hybrid varieties. Most of the hybrid seeds in vegetable crops are imported from abroad. Considering the demand for hybrid vegetable varieties, the National Horticulture Research Centre (NHRC), Khumaltar, Lalitpur has started hybrid breeding of vegetables using a conventional approach since the fiscal year 2003/04. With this effort, the tomato hybrid ‘Srijana’ was developed and registered in 2010. This variety was estimated to cover about 35% of the total tomato cultivated area. Two tomato hybrids, namely ‘Khumal Hybrid Tomato-2 (HRA14 × HRD7) and ‘Khumal Hybrid Tomato-3’ (HRA20 × HRD2), showed good performance and were released in the National Seed Board in 2021. It was found that the heterosis for the yield was 87% in ‘Khumal Hybrid Tomato-2’ and 95% in ‘Khumal Hybrid Tomato-3’ with a potential yield of 70 MT/ha and 60 MT/ha, respectively, under open field conditions. Similarly, a comparative study of 7 tomato hybrids at different research stations was carried out and it showed that F1 (HRA13 × HRD7) could be a potential hybrid for the western region with a potential productivity of 116.8 MT/ha under a protected cultivation system. Hybrid breeding of cucumber was also initiated in the fiscal year 2007/08. A total of 12 crosses in cucumber were performed and two hybrids F1 (HRDCUC004 x RDCUC001), 107 MT/ha and F1 (HRDCUC009 × HRDCUC003) 150 MT/ha were found promising. Hybrid breeding in brinjal, hot pepper and bitter gourd has also been started. Furthermore, key problems and way forward to strengthen hybrid vegetable breeding in Nepal were also discussed.

A micro-computed tomography evaluation of voids using calcium silicate-based materials in teeth with simulated internal root resorption

Tek, Vildan,Turker, Sevinc Aktemur The Korean Academy of Conservative Dentistry 2020 Restorative Dentistry & Endodontics Vol.45 No.1

Objectives: The obturation quality of MTA, Biodentine, Total Fill BC root canal sealer (RCS), and warm gutta-percha (WGP) in teeth with simulated internal root resorption (IRR) was evaluated by using micro-computed tomography. Materials and Methods: Standardized IRR cavities were created using 40 extracted maxillary central incisor teeth and randomly assigned into 4 groups (n = 10). IRR cavities were filled with MTA, Biodentine, Total Fill BC RCS (bulk-fill form) and WGP + Total Fill BC RCS. Percentage of voids between resorptive cavity walls and obturation material (external void), and inside the filling materials (internal voids) were measured. Results: Total Fill BC sealer in the bulk-fill form presented significantly highest values of external and internal void percentages (p < 0.05). Biodentine showed a significantly lowest external void percentage (p < 0.05). WGP + Total Fill BC RCS presented significantly lower values of internal void percentages than all groups (p < 0.05), except Biodentine (p > 0.05). Conclusion: None of the filling materials were created void-free obturation in resorption cavities. Biodentine may favor its application in teeth with IRR over Angelus MTA and bulkfill form of Total Fill BC.