• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.1
• /
• pp.45-58
• /
• 2013

The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.

• Journal of the Korean Society of Radiology
• /
• v.7 no.2
• /
• pp.107-112
• /
• 2013

There is an Ankle Oblique(Broden' low) as an examination for the patient whose ankle was encased in orthopedic plaster. Some types of Ankle Joint coalition - Calcaneonavicular coalition, Talocalcaneal coalition and Naviculocuneiform coalition. This study is focused on the relation between Ankle Joints and the structural change of soft tissues, also finding the most proper angle to obtain good images of Ankle Joint from the patient who wore a plaster on his ankle, when we x-ray with Harris-Beath View($30^{\circ}{\sim}55^{\circ}$) - for observing Subtalar joint, Calcaneus Fracture, Subtentaculum, Tali Fracture and Talocalcaneal coalition. We intend to get the angle which makes us achieve the good image that shows Calcaneus Fracture, Subtentaculum, and Tali Fracture by changing internal angles of the patient's ankle. We evaluated the images obtained from 51 patients with PACS monitor. The result of the evaluation, subtalar joint was not seperated but opened, and Subtentaculum Tali Fracture was seen overlaid. at the angle 30, we could observe Calcaneus Fracture, Subtentaculum Tali Frature and the front part of behind side of subtalar joint well. And Calcaneo Navicularcoalition, Talocal Canealcoalition, Naviculo Cuneiform coalition condition were clearly seen at that angle. At the angle 35, we could achieve the clear images of subtalar comminuted fracture, talus, the behind joint of heel bone and get the high definition image on the degree of talocalcaneal joint separation. In addition to, We could obtain the good wide image of Sinus Tarsi. At the area of 45, We can distinguish the soft tissues from gyps separation. The outer-talus and density of the bone were definitely seen and Calcaneus is more separated than that of at the angle of 35, but this image is distorted. Calcaneus, Subtentaculum Tali show $1.20{\pm}0.414$ at the angle 25, $2.47{\pm}0.516$ at the angle 30, $2.27{\pm}0.458$ at the angle 45. This difference is statistically meaningful. (p<0.05). Including the degree of distortion, The distortion appears less at the area of $30^{\circ}$ but at the area of 40, there is heavy distortion. So, We could get the best image for making a diagnosis. At the $30{\sim}35^{\circ}$ degree for X-raying ankle. and at the $30{\sim}40^{\circ}$ for Calcaneus Fracture, Subtentaculum Tali Fracture.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.33 no.4
• /
• pp.643-652
• /
• 2006

The purpose of this study was to elucidate the size and morphologic characteristics of maxillary primary first molars in Korean children using three-dimensional laser scanner and compare three-dimensional image with preformed stainless steel crown. Scanned three-dimensional images of dental cast taken from 132 children(male 62, female 70) by three-dimensional laser scanner(Breuckmann opto-Top HE100, INUS, Korea) were used. Mesiodistal diameter, buccolingual diameter, occlusogingival height and crown shape of each image were calculated by Rapidform 2004 program(INUS, Korea). The values were statistically compared by independent samples t-test with 95% of significant level. The results were as follows : 1. No significant difference in crown size was found between left and right maxillay primary first molar(p>0.05). 2, Significant difference in mesiodistal diameter, buccolingual diameter, buccal occlusogingival height was found between male and female (p<0.05), and crown size of male was bigger than that of female. 3. Average image of maxillay primary first molar was shaped three-dimensionally and measured. In comparison with 3M stainless steel crown, this image was similar with No.4 or No.5 SS crown in male, No.4 in female. In comparison with ILSUNG SS crown, this image was similar with No.5 in male, No.4 in female. 4 Mesiolingual line angle area, distolingual line angle area and buccogingival ridge were more obvious in average image than 3M stainless steel crown. ILSUNG SS crown was more square and had longer mesiodistal diameter than average 3D image.

• The Journal of Korean Academy of Prosthodontics
• /
• v.42 no.5
• /
• pp.514-523
• /
• 2004

Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.

• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.3
• /
• pp.320-327
• /
• 2009

Statement of Problem: Although many efforts have been continually made to estimate long term prognosis of removable partial dentures, the complication of removable partial dentures was still found because of inaccurate fabrication procedure and improper maintenance care. Purpose: The purpose of this study was to evaluate the clinical status of removable partial dentures. Material and methods: A total of 112 individuals with 153 removable partial dentures (35 - 87 years, 64 women and 48 men) were examined by intra-oral examination, diagnostic cast and radiographic examination. Results and conclusion: The results of this study were as follows: 1. Length of service of removable partial dentures was $5.3{\pm}4.3$ years (mean), 4.0 years (median). 2. A total of 45 removable partial dentures were considered failures. The loss of 18 abutments of 369 was founded. 3. Type of arch, Kennedy classification and type of opposite dentition were found to have no influence on longevity and success rate of removable partial dentures (P > .05). 4. Most common major connector was the palatal plate in maxilla and the number of lingual bar and linguoplate designed in mandible were similar. 5. The circumferential type retainer was the most commonly used retainer. 6. Sixty-three percent of the class I and II removable partial dentures incorporated indirect retention into the design. 7. Approximately 81% of the removable partial dentures had at least one defect. Excessive wear of posterior teeth (27.9%), lack of integrity (23.2%), lack of stability (22.6%) were frequent defects of removable partial dentures.

• Korean Journal of Ichthyology
• /
• v.31 no.4
• /
• pp.222-234
• /
• 2019

Fish community characteristics and habitat aspects of endangered species, Pseudopungtungia tenuicorpa and Acheilognathus signifer were investigated in the Hwayangcheon Stream of Songnisan National Park, a tributary of the Hangang River, Korea from April to October 2018. During this period, there were 29 species of 8 families collected from 11 survey stations using kick nets, cast nets long bag set nets. The dominant and subdominant species were Zacco koreanus (38.81%) and Rhynchocypris oxycephalus (16.64%), respectively. The next most abundant species were Z. platypus (14.28%), Pungtungia herzi (6.92%), Hemibarbus longirostris (4.52%), Pseudogobio esocinus (3.51%), A. signifer (2.31%) and P. tenuicorpa (1.90%). Among the fish collected, 18 species (62.1%) were Korean endemic species. Endangered species were A. signifer, P. tenuicorpa and Gobiobotia brevibarba. From upstream to downstream, the dominance index has gradually decreased, but number of species and individuals, diversity and evenness has gradually increased. Also, river health (index of biological integrity) is assessed as good (St. 1~8) and very good (St. 9~11). Fish communities were divided into four sections by the similarity index based on species and their numbers, i.e., upper section (St. 1~2, 4~5), upper-middle section (St. 3, 6), middle section (St. 7~9) and lower section (St. 10~11). Endangered species, Pseudopungtungia tenuicorpa inhabited in mostly lower section (St. 10~11) with rock and boulder bottoms, and age groups in April estimated from total length indicated that the 44~61 mm group is 1 year old, the 66~81 mm group is 2 years old, the 88~99 mm group is 3 years old, and the 104~107 mm group is more than 4 years old. Also, endangered species, A. signifer inhabited in middle-lower section (St. 7~11) with boulder and cobble bottoms and slow velocity, which the place inhabited by water plants. Meanwhile, their age structure in April estimated from total length indicated that the 30~43 mm group is 1 year old, the 48~58 mm group is 2 years old, the 62~77 mm group is 3 years old, and the 84~100 mm group is more than 4 years old. The sex ratio of female (47) to male (42) was 1 : 0.89.

• Journal of Oral Medicine and Pain
• /
• v.30 no.1
• /
• pp.69-77
• /
• 2005

The purposes of this study were to develop and introduce a novel intraoral appliance for bruxism composed of power switch and biofeedback device and further to examine inter- and intra-reliability of the appliance prior to clinical tests. The newly-developed appliance consisted of detection sensors, a central processing unit (CPU), a reactor and a storage unit and a displayer. Compact-sized, waterproof switches were selected as bruxism detection sensor and any sensor activation by clenching or grinding event was processed at the CPU and transmitted, by radio wave, to the reactor and storage unit and triggered auditory or vibratory signal, subsequently producing biofeedback to the patient with bruxism. The data on bruxing event in the storage unit can be displayed on the computer, making it possible analyzing frequency, duration and nature of bruxism. Cast models were obtained from ten volunteers with normal occlusion to evaluate reliability of the appliances. For inter-operator reliability on the intraoral appliances, each operator of the two fabricated the appliance for the same subject and compared the minimal contact forces provoking auditory biofeedback reaction in vertical, lateral and central directions. Intra-operator reliability was also investigated on the appliances made by a single operator at two separate times with an interval of two days. Conclusively, the newly-developed appliance is compact and safe to use in oral circumstance and easy to make. Furthermore, it had to be proven reliability excellent enough to apply in clinical settings. Thus, it is assumed that this appliance with the processor and the storage of data and auditory or vibratory biofeedback function is available and useful to analyze and control bruxism.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.2
• /
• pp.125-140
• /
• 2011

The remnant of temporary cement on the intaglio surface of cast restoration may have a negative effect on the retentive strength of permanent cement. This study was to evaluate the effect of temporary cement cleaning methods on the retentive strength of cementation type implant prostheses. Prefabricated implant abutments - height 5.5mm, diameter 4.5mm, 6 degree axial wall taper with chamfer margins were used. Forty copings-abutment specimens were divided into four groups(each n=10) according to the cleaning methods for temporary cement(Temp-$Bond^{(R)}$) as follows : no temporary cementation(the control group), orange solvent, ultrasonic cleaning, air borne-particle abrasion. After the application of temporary cement and the separation, the cleaning procedure was performed according to the protocol of each group. The specimens were cemented with $Premier^{(R)}$ Implant $Cement^{TM}$. After the permanent cementation, the specimens were subjected to thermocycling and pulled out from the specimens with a universal testing machine at a cross-head speed of 0.5mm/min. After the retentive strength test, all the specimens were cleaned using ultrasonic cleaning, abraded with air borne-particles, and steam-cleaned. Likewise, the specimens were temporarily cemented(Temp-$Bond^{(R)}$ NE), cleaned according to the protocol of each group, cemented with $Premier^{(R)}$ Implant $Cement^{TM}$ and subjected to thermocycling and measurement of their retentive strength. The mean of group with orange solvent were significantly lower than those of other groups(p<0.05). There was no significance between group with ultrasonic cleaning and group with air borne-particle abrasion. Group with ultrasonic cleaning and group with air-particle abrasion were no significance at control group. There was no significance between group cemented with Temp-$Bond^{(R)}$ and group cemented with Temp-$Bond^{(R)}$ NE. Within the limitation of this study, it can be concluded that the temporary cement cleaning method with only orange solvent may have a negative effect on the retentive strength of permanent cement. Ultrasonic cleaning and air borne-particle abrasion methods are recommended for the temporary cement cleaning method on cementation type implant prostheses.

• The Journal of Korean Academy of Prosthodontics
• /
• v.59 no.4
• /
• pp.395-404
• /
• 2021

Purpose. The purpose of present study was to evaluate the effect of changing structural stability of wax disc on the fit of prosthesis when the milling proceeded in order. Materials and methods. Prepared maxillary left first molar was used to fabricate a Ni-Cr alloy reference model. This was scanned to design crown and then wax pattern was milled, invested and cast to fabricate prosthesis. The wax patterns located in a row centrally within a single wax disc were set into a total of five groups ranging from WM1 group that was first milled to WM5 group that was last milled and the number of each group was set as 10. Silicone replica technique was used to measure the marginal gap, axial internal gap, line angle internal gap, occlusal internal gap. Data was evaluated with one-way ANOVA with significance level set at α = .05 and then Tukey HSD test was conducted for post analysis. Results. Marginal gap measured in each group, it was 40.41 ± 2.15 ㎛ in WM1 group, 40.44 ± 2.23 ㎛ in WM2 group, 39.96 ± 2.25 ㎛ in WM3 group, 39.96 ± 2.48 ㎛ in WM4 group, and 40.57 ± 2.53 ㎛ in WM5 group. No significant difference was found between groups. The significant difference between the groups was also not found in the axial internal gap, line angle internal gap, and occlusal internal gap. Conclusion. Internal and marginal fit of single crown to the sequential order of milling processing in the single machinable wax disc did not seem to be affected by the sequence.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.4
• /
• pp.136-161
• /
• 2014

This paper investigates the Buddhist sculpture and wall-painting enshrined in the halls of Bunhwangsa (Bunhwang temple) at Gyeongju in the mid-Silla period, which are thoroughly unknown to us except through textual records of Samgukyusa compiled by Priest Ilyeon in the late thirteenth century. According to Samgukyusa, a clay portrait-sculpture of Monk Wonhyo, made by his son Seolchong, was placed in Bunhwangsa. This image faced to the side, because he turned his body toward Seolchong when Seolchong bowed to this image. This story suggests that the portrait image of Wonhyo was most likely made after the Vimalakirti images, which were popular in China from the Six Dynasties period on, especially the Vimalakirti images of the early Tang period, turning his head and body toward Bodhisattva Manjusi seated opposite. The Vimalakirti image of Seokkuram might show the portrait image of Wonhyo. A wall-painting of a Thousand-Armed Avalokiresvara who has a thousand arms with a thousand eyes, called by the name 'Great Mercy with a Thousand Hands', was enshrined on the north wall of the left hall of Bunhwangsa. During King Gyeondeok's reign, Himyeong and her five-year-old blind child prayed before this image, and the blind child gained eyesight. While praying, they sang a song pleading for one of the thousand eyes which the Bodhisattva had in his hands. This song implies that Thousand-Armed Avalokiresvara had a thousand eyes, one painted on each hand. The fact that Thousand-Armed Avalokiresvara of Bunhwangsa was called 'Great Mercy with a Thousand Hands' indicates that this painting was based on the scripture Thousand-Armed Avalokiresvara Sutra translated by Bhagavaddharma in about 655, in the Tang period, which also has 'Great Mercy' in its title. In the year 755, a gilt bronze image of Medicine Buddha was made in Bunhwangsa, using nearly 61 tons of bronze to cast. The huge amount of bronze suggests it includes not only the Buddha statue but many other images such as two attendant Bodhisattvas of Suryaprabha and Candraprabha, Eight Great Bodhisattvas, or Twelve Guardians. Seven images of Medicine Buddha might have been made in accordance with the scriptural text of Seven Medicine Buddha Sutra translated by Monk Yijing. Textual evidence and recent excavation have revealed that seven images of Medicine Buddha and their whole attendant images based on Seven Medicine Buddha Sutra were made in the Nara period from 751 to 762 when Queen Gomyo contructed Sinyakusiji temple for the recovery of her husband Shomu. It is fair to assume that one or seven Medicine Buddhas and a whole group of his (their) attendant images were made for the main hall of Bunhwangsa temple in 755.