• Imaging Science in Dentistry
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• v.49 no.2
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• pp.123-130
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• 2019

Purpose: This study was conducted to characterize the relationship of the angulation between the tooth root axis and alveolar bone axis with anterior alveolar(AA) arch forms and sagittal root position (SRP) in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: CBCT images that met the inclusion and exclusion criteria were categorized using a recent classification of AA arch forms and a SRP classification. Then, the angulation of the root axis and the alveolar bone axis was measured using mid-sagittal CBCT images of each tooth. The relationships of the angulation with each AA arch form and SRP classification were evaluated using 1-way analysis of variance and a linear regression model. Results: Ninety-eight CBCT images were included in this study. SRP had a greater influence than the AA arch form on the angulation of the root axis and the alveolar bone axis(P<0.05). However, the combination of AA arch form and SRP was more predictive of the angulation of the root axis and the alveolar bone axis than either parameter individually. Conclusion: The angulation of the root axis and alveolar bone axis demonstrated a relationship with the AA arch form and SRP in teeth in the anterior esthetic region. The influence of SRP was greater, but the combination of both parameters was more predictive of root-to-bone angulation than either parameter individually, implying that clinicians should account for both the AA arch form and SRP when planning implant placement procedures in this region.

• Journal of Integrative Natural Science
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• v.9 no.2
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• pp.152-154
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• 2016

Arbitrary polynomial of degree n can be written in Chebyshev form. In this paper, we generalize this Chebyshev form and study its root distributions.

• Communications of the Korean Mathematical Society
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• v.29 no.3
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• pp.489-496
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• 2014

We drive a closed-form expression for the price of a European quanto call option in the double square root stochastic volatility model.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.151-154
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• 2007

To build up the green roofs, it must not adverse effect to durability and structural safety. That is conducted by safety system which consist of waterproofing to form basically, root barrier to protect the waterproofing. The reason why root barrier form is to protect the penetration force of root growth and the root could penetrate concrete surface, move inward so far. It may cause shorten the life span on concrete structure. For this problem, government constantly demand the solution to form the root barrier for waterproofing and concrete structure before the building is service. However, the technical action is not fully prepared. Therefore, in this study, we would like to suggest the workability and suitability of the copper plate to solve not only the side of waterproofing but also root barrier for green roof system and exhibit the mechanism for root penetration resistance and corrosion resistance.

• The korean journal of orthodontics
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• v.34 no.3 s.104
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• pp.241-251
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• 2004

Previous studies have focused on the causes of root resorption after orthodontic treatment and treatment methods to reduce this phenomenon, and have been mainly associated with developed, mature roots. As parents become increasingly interested in their children's' dentition, orthodontists are performing fixed orthodontic treatment on patients of less than 10 years and before the completion of the immature root. Thus, the author evaluated the changes of root length and root form of maxillary immature incisors after orthodontic treatment, compared with those of mature teeth, and investigated the correlation according to gender, treatment duration, and displacement of incisors. The sample consisted of an immature root group of twenty-eight persons (between 8 and 10 years old) and a mature root group of thirty-one persons (between 11 and 15 years old). The crown and root length of the maxillary four incisors were measured with a periapical radiograph, changes in root length and crown-root ratio were calculated, and root form was classified according to a scoring system. The results were as follows. 1. The development of immature roots was not affected by orthodontic treatment and mostly showed normal root length and apical form. 2. Root length of immature teeth was sustained or became shorter, partially in long treatment duration or with open bite patients. Even though the teeth reached their normal root length, they demonstrated a blunt form. 3. Most of the mature roots showed mild resorption, and the form of mature roots was more blunt than the developed form of the immature roots (p<0.05). 4. The developed form of the immature roots was statistically related to treatment duration, while the form of the mature roots was significantly related to the displacement of incisors (p<0.05). 5. In contrast, other variables such as gender, classification of malocclusion, changes in overbite, and changes of U1 to SN showed no correlation with the root resorption of both groups.

• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.22-39
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• 1995

Following "Studies on Characteristics of Pin us densiflora Forest in Kangwon Province (III)- Studies on the Tree-Root Form and Distribution on the Campus Forest, Kangwon Nat'l Univ.-", the form and distribution of root system was investigated for 5 trees in Songhyun-Ri, Wangsan-Myon, Myengju-Gun, Kangwon Province. Vertical tap roots and flat roots were established very well. In root distribution, fine roots were sparsly distributed (+), although 7 smaller quadrats($10{\times}10cm$) were found with the value of 1(+~20%) index of fine root; big roots 0.2cm thick in diameter were most common. More than 50% of fine roots and big roots were found around the depth of 10~30cm in soil.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.276-282
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• 2013

Purpose: The aim of this study was to explore root shape abnormalities, to investigate the influence of root form abnormalities on periodontal attachment loss, and to gather basic data to assist in the diagnosis and treatment of aggressive periodontitis. Methods: From January 2010 to June 2012, a survey was conducted of all 3,284 periodontitis patients who visited the Department of Periodontology, Daejeon Dental Hospital, Wonkwang University School of Dentistry. Clinical parameters (probing depth, periodontal attachment loss, missing teeth) were measured and a radiographic examination was performed at the baseline. We classified the root shape abnormality of bicuspids and molars based on Meng classification. Results: The periodontal attachment loss was the highest at the maxillary first molar (6.03 mm). The loss of the second molar was prominent. Type V deformity was shown to be the most common in the second maxillary and mandibular molars (P<0.05). Type V root shape was associated with the highest attachment loss (P=0.01). Conclusions: Considering the small population and limited design of this study, definitive conclusions cannot be drawn. We suggest larger scale, methodologically more sophisticated studies that include normal controls and chronic periodontitis patients to clarify whether root form abnormalities are a potential risk factor for aggressive periodontitis.

• Journal of Forest and Environmental Science
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• v.10 no.1
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• pp.8-24
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• 1994

Because of the underground existence of roots, a few studies have been reported on root system. The developmental information of roots should be understood for the studies of specific tree traits and the influence of such traits on the soil surface fixation. In order to clarify the specific character of pine forest in Kangwon Province, the investigation on the form and distribution of root system of pine trees were carried out for 5 trees in the Campus Forest, Kangwon National Univ.. Root form was very well in flat root. As soil depth was approximatly 50cm, fine roots were very sparsly distributed(+), roots of 0.2cm in diameter were most common and roots > 0.2cm were very rare, also thickness thined. 60~70% all the roots were developed at the depth of 0~30cm, where big roots were below 0.9cm in diameter and fine roots were higly sparse(+).

• The Journal of Korean Academy of Prosthodontics
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• v.23 no.1
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• pp.13-37
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• 1985

Biocompatibility of dense synthetic hydroxylapatite is well known and the direct bond with adjacent bone developed. The purpose of this study was to evaluate the potential of clinical application of tooth ash for preservation of alveolar ridge. For this purpose the author performed an experimental implantation of the particulate and root form of both pure dense hydroxylapatite and tooth ash in alveolar sockets immediately after extraction. The pure dense hydroxylapatite was particulate form and root form made by Calciteck Inc. The tooth ash was prepared by incineration at $950^{\circ}C$, and the syrindrical form of the tooth ash was sintered and trimmed to fit the size of the each extraction socket of 10 mongrel dogs. After sugery the clinical, roentgenographical, and histological observation was carried out. The results obtained were as follows; 1. Clinical observation disclosed no dehiscence and exfoliation due to tissue rejection. 2. Vertical resorption of alveolar bone occurred in all experimental sockets as well as the control sites on the roentgenograph. 3. Osteoclastic activity appeared at the inner surfaces of the crestal alveolar bone on the 1st week but disappeared on the 2nd week. 4. There were macrophages in the particulate form on the 1st and 2nd week after surgery but no macrophages appered in the root form. S. New bone formation was developed from the bony wall of experimental sockets and grew to bond with the implant materials. In particulate form the new bone formation did not occur in central zone independently. 6. Tooth ash implant sites were covered with the newly formed bony trabeculation from third week, but Calcitite particles were covered with soft tissue. 7. Generally the healing occurred more rapidly in control sites than in implant sites.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.1-11
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• 2017

In this study, novel approximate form of the square-root operator of three dimensional acoustic Parabolic Equation (3D PE) is proposed using a rational approximant for two variables. This form has two advantages in comparison with existing approximation studies of the square-root operator. One is the wide-angle capability. The proposed form has wider angle accuracy to the inclination angle of ${\pm}62^{\circ}$ from the range axis of 3D PE at the bearing angle of $45^{\circ}$, which is approximately three times the angle limit of the existing 3D PE algorithm. Another is that the denominator of our approximate form can be expressed into the product of one-dimensional operators for depth and cross-range. Such a splitting form is very preferable in the numerical analysis in that the 3D PE can be easily transformed into the tridiagonal matrix equation. To confirm the capability of the proposed approximate form, comparative study of other approximation methods is conducted based on the phase error analysis, and the proposed method shows best performance.