• 대한장애인치과학회지
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• 제13권1호
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• pp.6-13
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• 2017

Premolars show the greatest variation in development and eruption. The present case report identified characteristics of eruption of maxillary premolars with delayed development. Multiple maxillary premolars with delayed development were found to have a palatal ectopic eruption pattern, which was self-corrected through eruption guidance by extraction of preceding primary teeth at the stage of root development when eruption force was maximal. In addition, delayed eruption due to delayed development was substantially improved by eruption guidance. Early erupted premolars with less than 1/3 of root development were induced to have normal root development using stabilizing appliance. The maxillary premolars with delayed development reported in the present study showed no complications such as impaction, space loss by delayed eruption, or insufficient root development.

• 한국환경복원기술학회지
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• 제14권3호
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• pp.47-55
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• 2011

Cicada is a very familiar insect to people but habitat characteristics of them are not well known. To investigate habitat characteristics of cicada nymph, plant species, plant cover, soil hardness, accumulated organic mass, organic content in soil, and root density were investigated at 11 sites in an apartment complex garden in Seoul. Selected sites had different densities of cicada nymph case above the ground. Density of cicada nymph case was positively correlated with accumulated organic mass, organic content in soil, and root density and negatively correlated with soil hardness. Even though shrub coverage was not linearly correlated with the density of cicada nymph case, 80% cover of shrub was necessary for the high density of them. Data in this study suggested that organic matter in addition to root density be the primary limitation factor of cicada nymph and high amount of litter-fall decrease soil hardness through the increase of soil organic matter. This study suggests that the density of cicada nymph can be managed through organic content in soil.

• 대한소아치과학회지
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• 제21권2호
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• pp.439-455
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• 1994

생리적 치근 흡수가 뒤따르는 유치 치주인대의 신경분포 및 변화를 평가하기 위하여 생후 1, 2. 3. 4. 5개월된 개의 유치 치주인대와 9개월된 영구치 치주인대를 대상으로 neurofilament protein(NFP) 을 이용한 면역조직화학적 방법으로 관찰하여 다음과 같은 결과를 얻었다. ${\bullet}$ 유견 유치의 치주인대 신경분포는 치근단 1/3 부위에서 가장 밀집되어 있었으며 치근 중앙부로 향할수록 현저하게 감소되었으며 전체적으로 그 분포밀도 및 분지 정도는 영구치와 비교시 약한 양상을 나타냈다. ${\bullet}$ 구치부에 비해 전치부에서 신경분포가 보다 발달된 양상을 보였으며 구치 치근이개부 치주인대에서는 신경섬유가 관찰되지 않았다. ${\bullet}$ 유치근이 흡수됨에 따라 신경분포 정도도 감소되었으며 탈락시기의 치근 주위에서는 신경섬유를 관찰할 수 없었다. ${\bullet}$ 치은점막상피의 신경지배는 치아가 발육함에 따라 감소되는 양상을 나타내었으며 설측점막이 순측점막보다 더 발달된 신경분포 양상을 관찰할 수 있었다. ${\bullet}$ 유치 치주인대 신경말단 형태는 수지상의 신경말단 형태를 나타내고 있었으며 전형적인 Ruffini 신경말단은 거의 관찰할 수 없었다. 이상의 결과를 미루어 신경섬유의 분포는 기능과 밀접한 관계가 있는 것으로 생각되고 더우기 유치의 생리적 치근흡수에 따른 치주인대에 신경섬유의 분포 및 변화는 유치의 성장발육에 따른 하나의 변화라고 생각된다.

• 대한한방부인과학회지
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• 제35권3호
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• pp.122-136
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• 2022

Objectives: The aim of this study is to investigate Heart Rate Variability (HRV) characteristics of patients with primary dysmenorrhea at the menstrual phase. Methods: 7 databases (Pubmed, Cochrane library, CNKI, RISS, KISS, OASIS, ScienceON) were searched for eligible studies published before 2021 December. The studies comparing HRV between patients with primary dysmenorrhea and controls were included. A random-effects model was used to evaluate differences of HRV parameters between patients with primary dysmenorrhea and controls. Results: 4 articles were included in this review based on inclusion and exclusion criteria. SDNN (Standard deviation of NN intervals), RMSSD (Square root of the mean squared difference of successive NN intervals), mean PR (Mean of pulse rate), LF (Low frequency), HF (High frequency), was the most frequently used as HRV parameters. RMSSD was significantly lower in patients with primary dysmenorrhea than controls. There was no statistically significant difference of other HRV parameters between patients with primary dysmenorrhea and controls. Conclusions: This study suggests that parasympathetic activity and overall functions of autonomic nervous system might be decreased in patients with primary dysmenorrhea at the menstrual phase. In the future, well-designed clinical studies using HRV and additional meta-analysis should be conducted to obtain a wealth of information about HRV characteristics of patients with primary dysmenorrhea.

• 한국산림과학회지
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• 제99권5호
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• pp.726-735
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• 2010

Publications with the data on allometric equation, biomass and productivity of major oak forests in Korea were reviewed. Different allometric equations of major oak species showed site- or speciesspecific dependences. The biomass of major oak forests varied with age, dominant species, and location. Aboveground tree biomass over the different oak species was expressed as a power equation of the stand age. The proportion of tree component (stem, branch and leaf) to total aboveground biomass differed among oak species, however, biomass ranked stem > branch > leaf in general. The leaf biomass allocation over the different oak species was expressed as a power equation of total aboveground biomass while there were no significant patterns of biomass allocation from stem and branch to the aboveground biomass. Tree root biomass continuously increased with the aboveground biomass for the major oak forests. The relationship between the root to shoot ratio and the aboveground tree biomass was expressed by a logarithmic equation for major oak forests in Korea. Thirteen sets of data were used for estimating the net primary production (NPP) and net ecosystem production (NEP) of oak forests. The mean NPP and NEP across different oak forests was 10.2 and 1.9 Mg C $ha^{-1}year^{-1}$. The results in biomass allocation, NPP and NEP generally make Korean oak forests an important carbon sinks.

• 대한소아치과학회지
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• 제48권1호
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• pp.115-121
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• 2021

치아 만곡은 치아의 치관부 혹은 치근부에서 발생한 장축의 갑작스러운 굽힘을 의미한다. 이는 주로 선행 유치에 대한 기계적 외상이 원인이 되어 발생한다. 만곡된 치아는 종종 맹출 장애를 동반한다. 치아 만곡은 하악에서 드물게 발생하지만, 함입과 같은 심한 외상성 손상 이후에 충분히 발생할 수 있다. 본 증례는 두 명의 환아에서 확인된 선행 유치의 함입성 외상 이후 발생한 하악 영구 중절치에서의 만곡에 대한 증례를 보고하고 있으며, 두 증례 모두에서 만곡 치아의 자발적 맹출이 관찰되었다. 첫 번째 증례는 치관과 치근의 경계부 주위에서 측방치근만곡을 보였으며, 두 번째 증례는 치관만곡을 보였다. 본 증례를 통해서 유치의 외상 이후 하악 영구 중절치에서 치관부 만곡 혹은 치관과 치근 경계부에서의 측방만곡이 관찰된다면, 만곡치아의 자발적 맹출을 기대해 볼 수 있음을 확인할 수 있었다.

• 구강회복응용과학지
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• 제23권1호
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• pp.95-104
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• 2007

I. Objective The primary requirement of an endodontic root canal sealer is the biologic compatibility, because they remain in close contact with living periapical tissues over a long period of time. The aim of this study was the evaluation of cytotoxicity and genotoxicity of resin-based root canal sealers, AH 26 and ADSEAL. II. Material & Methods In this study, human periodontal ligament cells, human oral cancer cells (KB) and mouse osteoblasts (MC-3T3-E1) were used. Specimens of AH26, ADSEAL were eluted with culture medium for 1, 3, 5 and 7 days. Cytotoxicity was evaluated by using tetrazolium bromide reduction assay (MTT assay) for mitochondrial enzyme activity and cell viability. Genotoxicity was evaluated by using alkaline single cell gel electrophoresis assay (Comet assay). Also cell apoptosis induced by AH 26 was detected by Hoechst33258 staining. III. Results AH 26 and ADSEAL exhibited cytotoxic effects in all investigated cell groups. Genotoxicity was also noted for both sealers in mouse osteoblasts (MC-3T3-E1). But, ADSEAL presented significantly low cytotoxicity and genotoxicity compared with AH 26. Cytotoxicity and genotoxicity induced by AH 26 resulted in apopotosis. IV. Conclusion Our results clearly indicate that the recently invented ADSEAL has better biocompatibility than another resin based root canal sealer, AH 26. However ideal root canal sealer should have not only biocompatibility but also satisfactory physico-chemical properties such as sealing ability and stability. Thus continuous studies and developments should follow.

• The Korean Journal of Pain
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• 제9권2호
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• pp.390-394
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• 1996

Background: Occipital neuralgia is characterized by pain, usually deep and aching, in the distribution the second and/or third cervical dorsal root. Two broad groups of patients include primary occipital neuralgia with no apparent etiology and secondary neuralgia with structural pathology. Patients with occipital neuralgia can develop autonomic changes and hyperesthesia. In patients who have not improved with conservative treatment, we have carried out various nerve blocks and evaluated the effectiveness. Methods: In a series of 20 occipital neuralgia patients with no apparent etiolgy, we have carried out great occipital nerve blocks with needle TEAS. In patients who have not improved more than 75% on VAS with great occipital block, we have carried out C2 ganglion blocks and in patients who have not improved more than 75% with C2 ganglion block, C3 root blocks, C2/C3 facet joint blocks have been carried out in due order. Results: In 3 patients out of 10 patients who have not improved with great occipital nerve block, C2 ganglion block led to pain relief. A good response of C3 root block was achived in 2 of 7 patients without response to C2 ganglion block and C2/C3 facet joint block led to improvement in 1 of 5 patients without response to C3 root block. Conclusions: Nerve blocks like great occipital nerve block, C2 ganglion block, C3 root block, or C2/C3 facet joint block were effective in the patients who have not improved with conservative treatment.

• 대한치과보철학회지
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• 제36권2호
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• pp.293-301
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• 1998

The purpose of this study was to investigate the effects of load on root that was applied to edentulous area in three simulated situation, in each case the guiding planes of abutment were right vertical, 95 degrees, or 100 degrees to residual ridge. The 2-dimensional finite element method was used and the finite element model was prepared as fellows. Right mandibular 1st and 2nd molar was lost and the 2nd premolar with distal rest was used as primary abutment which had three different degrees of guiding plane. Then 150N of compressive force was applied to central fossae of the 1st and 2nd molars and von Mises stress and displacement was measured. The results were as follows; 1. Irrespective of slopes of guiding planes, the stress was concentrated on mesial side of root apex and distal side of coronal portion of root, in particular on junction with distal alveolar bone. As slopes of guiding planes were increased. stress on root and compact bone surrounding abutment was increased but no considerable effect was seen on compact bone of residual ridge. 2. Distal side of coronal portion of root limited by periodontal ligament was displaced distally and mesial side of apical portion was mesially. With slope of guiding plane increasing, the pattern of displacement was similar with one another but the quantity was increased. 3. Both abutment & alveolar bone were displaced downward and root of abutment, especially distal side of coronal portion, was displaced severely. As the guiding plane was tiffed more mesially over $90^{\circ}$, the degree of displacement was also increased.

• Restorative Dentistry and Endodontics
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• 제46권1호
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• pp.5.1-5.13
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• 2021

Objectives: The aim of the current study was to assess whether the amount of extruded debris differs for straight and severely curved root canals during retreatment using H-files, R-Endo, Reciproc and ProTaper Universal Retreatment (PTU-R) files. Additionally, the area of residual filling material was evaluated. Materials and Methods: Severely curved (n = 104) and straight (n = 104) root canals of maxillary molar teeth were prepared with WaveOne Primary file and obturated with gutta-percha and AH Plus sealer. Root canal filling materials were removed with one of the preparation techniques: group 1: H-file; group 2: R-Endo; group 3: Reciproc; group 4: PTU-R (n = 26). The amount of extruded material and the area of the residual filling material was measured. The data were analyzed with 2-way analysis of variance (ANOVA) and 1-way ANOVA at the 0.05 significance level. Results: Except for Reciproc group (p > 0.05), PTU-R, R-Endo, and H-file systems extruded significantly more debris in severely curved canals (p < 0.05). Each file system caused more residual filling material in severely curved canals than in straight ones (p < 0.05). Conclusions: All instruments used in this study caused apical debris extrusion. Root canal curvature had an effect on extruded debris, except for Reciproc system. Clinicians should be aware that the difficult morphology of the severely curved root canals is a factor increasing the amount of extruded debris during the retreatment procedure.