• The Journal of Korean Academy of Prosthodontics
• /
• v.22 no.1
• /
• pp.72-78
• /
• 1984

The notion that the axis of the shaft of the articulator must coincide the patient's mandibular transverse axis tells us the importance of locating the axis precisely. When using kinematic axis to transfer a cast to an articulator, the anatomic asymmetry of the contralateral points will result in certain distortion when the axis transferred to an articulator where the mechanical axis produces symmetry. In this study, after locating the true hinge axis point with Denar hinge axis locator, the discrepancies between true hinge axis point and arbitrary hinge axis point that was 13mm anterior from the posterior margin of center of trangus to the outer canthus of eye were measured. And the discrepancies between left and right true hinge axis point in the superoinferior and anteroposterior directions were measured. For this study, 20 dental students who have no missing teeth and no difficulties of mandibular movement were selected. Upper and lower cast of subjects were mounted on Denar Mark II articulator uisng Denar Slidematic face-bow and centric relation record for the measurement of discrepancies between left and right true hinge axis points. The results obtained as follows. 1. The mean distance from the arbitrary hinge axis point to the true hinge axis point was as follows. Right: horizontal distance; 1.99mm, vertical distance; 2.12mm, linear distance; 3.36 mm. Left: horizontal distance; 1.39mm, vertical distance; 2.06mm, linear distance; 2.09mm. Total: horizontal distance; 1.69mm, vertical distance; 2.09mm linear distance; 3.06 mm. 2. The 87.5% of true hinge axis points were within 5mm of the arbitrary hinge axis point. 3. The mean discrepancies between the right and left hinge axis point were 2.92mm in superoinferior direction and 4.74mm in anteroposterior direction. 4. When transferring the axis to the articulator, anatomic asymmetry between right: and left axis point produces in dislocation of cast on the articulator, and undesirable shift in esthetic tooth position will be resulted.

• Imaging Science in Dentistry
• /
• v.35 no.2
• /
• pp.97-103
• /
• 2005

Purpose : To determine if ultrasonography is a reliable technique to assess masseter muscle sites within intra- and interobserver and the scanning level and/or the muscle condition affect local cross-sectional dismension (LCSD) measurements of masseter muscle. Materials and Methods : 10 subjects without sign and symptom of temporomandibular disorders and missing posterior teeth were examined by ultrasonography. Bilateral ultrasonographic examinations were performed with a linear (B-scan) 7.5 MHz small-part transducer to register LCSDS of the masseter muscle on three different levels. Scans were made on relaxed and clenching condition. Three oral and maxillofacial radiologists measured at two sessions with a time interval of at least 5 minutes. Results : Variables such as 'condition' and 'level' had a significant effect on muscle measurements (p<0.05). There was no significant difference between 'sessions'(p>0.05) and 'observers' (p>0.05). LCSDS on lower scan level were significantly thinner than those on upper and middle level. Those on clenching condition were significantly thicker than those on relaxed condition (p<0.05). The scanning level with the highest reproducibility was middle with clenching condition (ICC=0.90, $MSE=0.55\%$). Conclusion : The data suggested that ultrasonography was a reliable method for measuring LSCD of masseter muscle in intra- and Interobserver and middle scan level showed the most reliable data.

• The Journal of Korean Academy of Prosthodontics
• /
• v.18 no.1
• /
• pp.99-109
• /
• 1980

An investigation was made Into 1,357 fixed bridges which had been performed at the Department of Prosthetic Dentistry, Seoul National University Hospital from 1973 to 1979. The purpose of this investigation was to establish a basic reference of the treatment with fixed bridges by obtaining statistical conclusions from the data concerning the patients who had been treated with fixed bridges. The following conclusions were obtained; 1. The ratio of the fixed bridges made on the maxillae to those made on the mandible was 1:1. 2. The cases of fixed bridges with one pontic were the most frequent, i.e., 946 cases out of total 1,357 cases, which were 69.7% of the total. 3. As the number of missing teeth increased, the number of the relevant cases of fixed bridges decreased. 4. The most frequent age group of the patients who had been treated with fixed bridges was the twenties, which was 40.8% of the total. As the age of the patients increased, the number of corresponding cases of fixed bridges decreased. 5. Most of the fixed bridges with more than three pontics were made at the anterior portion samely on the maxilla and on the mandible. 6. As for the retainers, the porcelain fused to metal crown and the partial veneer crown were frequently used at the anterior portion, while the full veneer crown was frequently used and the inlay and the attachment were used in some cases at the posterior portion. The locations of fixed bridges in the order of their frequency were: canine, lateral incisor, second bicuspid, central incisor, second molar, first bicuspid, first molar, and third molar on the maxilla; second bicuspid, second molar, first bicuspid, first molar, canine, third molar, lateral incisor, and central incisor on the mandible.

• Journal of Korean society of Dental Hygiene
• /
• v.13 no.5
• /
• pp.835-843
• /
• 2013

Objectives : The purpose of this study was to evaluate the chewing ability, oral-health related quality of life and factors in periodontal disease patients. Methods : Subjects were 111 patients having peridontal disease in 10 dental clinics in Busan and Gyeongsangnamdo. Questionnaire survey was carried out from July to August 2010. Questionnaire consisted of demographic characteristics, oral health factors, chewing ability and quality of life. Data were analyzed by descriptive analysis, t-test, ANOVA, correlation analysis, and multiple regression analysis using SAS(Ver 9.2) set at p<0.05. Results : Chewing ability was $44.85{\pm}8.8$, and their quality of life was $41.7{\pm}8.8$. Low level of quality of life was closely related to those factors as education, missing of more than 5 posterior teeth, certain subjective periodontal symptoms including swollen gums, sore gums, drifting gums, bad breath and toothache. The effective factors to the quality of life was chewing ability, bad breath and toothache. Conclusions : Chewing ability and quality of life were closely related each other. To enhance the quality of life, chewing ability should be improved. Proper treatment and effective method of management should also be properly considered to prevent the subjective periodontal symptoms and to minimize tooth loss.

• Korean Journal of Cleft Lip And Palate
• /
• v.2 no.1_2
• /
• pp.5-14
• /
• 1999

The aim of treatment of cleft lip and palate is to correct the cleft and associated problems surgically and thus hide the anomaly so that patients can lead normal lives. This correction involves surgically producing a face that does not attract attention, a vocal apparatus that permits intelligible speech, and a dentition that allows optimal function and esthetics. In neonatal periods, gross distortion of tissues surrounding the cleft requires considerable effort and time due to post operative functional defect and scarring and induces milk feeding problem, malocclusion of deciduous or permanent dentition, congenital missing teeth, skeletal dysplasia. The occurrence of a cleft deformity is a source of considerable shock to the parents of an afflicted baby, and the most appropriate approach is very important things. Thus we tried to analysis of dental arch, shape and size of deformity in cleft patients. The results were obtained as follows. 1. When the cast measurements of UCLP subjects at first visit it was found that the mean length was 9.29mm at the alveolar cleft width, also that was 11.7mm at the anterior width and 14mm at the posterior cleft width. 2. Comparison of UCLP group at first visit and just lip surgery, it was found that the older group showed a insignificant reduction in the width of the cleft in the alveolar, canine, and tuberosity regions. 3. The maxillary casts of the UCLP group at 6 months differ Significantly from those of the at 3 months in both length and width. but there was no statistical difference except anterior ridge length of nonclefted site. 4. Comparison at 6 months and 18 months, there was a greater change in length of the alveolar cleft width, intercanine width, and anterior cleft width. Maxillary arch became wider at both the canine region and intertuberosity region. also posterior anteroposterior length was increased but anterior AP length was decreased from 8.1mm to 7.7mm. There was meaningful increase at intertuberosity length; however, a significant reduction in width t-t'

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.3
• /
• pp.221-230
• /
• 2001

This study was performed to evaluate hard tissue cephalometric norms for Korean adults which can be implemented in surgical orthodontic treatment planning using selected horizontal reference plane especially for Koreans (Male: $SN-7.5^{\circ}$, Female: $SN-9.0^{\circ}$) and a simplified analytical method. 70 males and 70 females consisting of freshmen of Yonsei University from 1996 to 1997 and students from the Dental College of Yonsei University were chosen according to clinical examination and cephalometric analysis. The samples had normal profiles, normal anteroposterior skeletal relationship(ANB angle of $0^{\circ}$ to $4^{\circ}$ and Wits appraisal of -4.0mm to 0mm), and Class I molar and canine relationship. They had no missing or supernumerary teeth and had no experience of orthodontic or prosthetic treatment. After the selection of 23 landmarks and the construction of horizontal and vertical reference lines, 22 skeletal and 12 dental measurements were taken. These consisted of vertical and horizontal linear measurements and angular measurements. The results were as follows. 1. Mean and standard deviation of the measurements were calculated for males and females. 2. Most of the skeletal vertical measurements, and maxillary and mandibular length were bigger in males than females. Whereas anterior facial height ratio(N-ANS/ANS-Me) as well as maxillary and mandibular antero-posterior position in relation to the vertical reference line(N-perpendicular) showed no signigicant difference between sexes. 3. Maxillary and mandibular dental antero-posterior position in relation to the vertical reference line(N-perpendicular) showed no significant difference between sexes. 4. The upper incisor show(U1-Stms) was $2.1{\pm}1.7mm$ in males and $3.3{\pm}1.7mm$ in females. In this study, hard tissue cephalometric norms of Korean adults for orthognathic surgery were obtained.

• The korean journal of orthodontics
• /
• v.27 no.4 s.63
• /
• pp.523-538
• /
• 1997

In order to investigate TMD prevalence in malocclusion patients and to study its relationship with occlusal factors, 205 malocclusion patients (M67, F138, 6Y1M-46Y8M) were examined. The following examinations were carried out, Questionnaire personal history, TMD symptoms, and the associated factors Clinical examination : TMJ sound and maximum mouth opening Orthopantomogram : condyle abnormalities, length of Co'-Inc' and Co'-Go', ratio Co'- Inc'/ Co'-Go', and depth of antegonial notch Transcranial view limitation of anterior movement of condyle Model Angle classification, overjet, overbite, midline discrepancy, missing of posterior teeth, posterior crossbite, attrition of palatal cusp of maxillary molars, crowding/spacing The results could be summarized as follows, 1. The prevalence of TMD showed that Helkimo Anamestic Inder(Ai) 0 was $46.8\%$, Ai I was $22.0\%$, Ai II was $31.2\%$ and subjective symptoms increased with aging (p<0.001) and were frequent in females (p<0.05). 2. Flattening ($4.4\%$) was the most frequent condyle abnormality on Orthopantomogram, and $8.3\%$ of subjects showed some abnormalities on Orthopantomogram. 3. The cases with neck and shoulder pain (p<0.001), clenching, lip biting (p<0.01), and headache (p<0.05) showed higher scores of Ai. 4. Angle class II showed high frequency of condylar abnormalities on Orthopantomogram, and subjects whose palatal cusp of maxillary molars had been attrided had the tendency to show high hi scores (p<0.05). The other occlusal factors had nothing to do with the symptoms of TMD. 5. In the cases that 1)the value of Co'-Inc', Co'-Go' or Co'-Inc'/Co'-Go' were low or 2)the differences of Co'-Go' or Co'-Inc'/Co'-Go' between the right and the left were large, condylar abnormalities were frequently obserbed on Orthopantomogram.

• The Journal of Korean Academy of Prosthodontics
• /
• v.36 no.2
• /
• pp.323-335
• /
• 1998

Clinically, the curve of Spee is widely applied as a determined level of the occlusal curvature when the oral rehabilitation and the reconstruction of the prosthesis is needed at the malalignment dentition due to the missing, extrusion, and the inclination of the teeth. The purpose of this study was to analyze the curve of Spee of the occlusal curvature which influences to the occlusal form and the location three dimensionally, and then was to measure the radius and the degree of curvature of the curve of Spee and also was to investigate the influence to the cuspal inclination according to the change of the inclination of the curve of Spee which was analyzed by AutoCAD R.13 program at the gnathological cast and the cephalometric radiograph. The following results were obtained : 1. The radius of the curve of Spee was the mean of $11.74{\pm}3.64cm$ in the model, $12.75{\pm}4.63cm$ in the radiograph and there was no significant difference statistically between the model and the radiograph(P>0.001). 2. The radius and the degree of curvature of the curve of Spee showed negative correlation(r=-0.80), while the radius and the degree of curvature of the curve of Spee in relation to the length of the curve of Spee did not show correlation. 3. The case of the curve of Spee inclined to the posterior, that is. $Post.M{\theta}$ group showed the mean of $4.73{\pm}3.64$, positive correlation to the P2m, M1mm, M1dm, M2dm, and especially the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.70). 4. The case of the curve of Spee inclined to the anterior, that is, $Ant.M{\theta}$ group showed the mean of $3.28{\pm}3.59$, positive correlation to the P2m, M1mm, and also the greatest correlation coefficient to the mesial inclination angle of the mesio-buccal cusp tip of the first molar(r=0.78

• Journal of Periodontal and Implant Science
• /
• v.38 no.3
• /
• pp.413-428
• /
• 2008

Purpose: Given the predictability of dental implant procedure from the studies of successful osseointegration, implant dentistry is often the treatment of choice to replace missing teeth in edentulous patient instead of the fixed prosthesis or removable denture. The $Renova^{(R)}$ dental implant has a RBM(Resorbable Blast Media) surface, internal hex prosthetic connection and a tapered design. At this study gives the analysis of the implant and the short term survival rate of the implant. Material and Methods: In this study, a multilateral analysis was performed on the subjects undergoing placement with $Renova^{(R)}$ implant between August 2006 and February 2008 in Yonsei University dental hospital. 96 implants were placed in 56 patients and they were surveyed for cumulative survival rate. Among them 78 implants in 44 patients were surveyed for the rest analyses. Result: 1. The cumulative survival rate was 96.88% of 96 implants in 56 patients. 2. The mean marginal bone loss was 0.803mm and the marginal bone loss in augmentation group has higher value than the marginal bone loss in non augmentation group. 3. The health scale for the implants were 87% in success group, 9% in satisfactory survival group, 1% in compromised survival group, and 3% in failure group. 4. Two implants placed in poor bone posterior area by 2-stage failed during prosthetic procedure. Conclusion: $Renova^{(R)}$ dental implant showed high cumulative survival rate in installation on partial edentulous ridge and could be a predictable implant system.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.2
• /
• pp.125-134
• /
• 2023

When the patient with class III malocclusion needs extensive oral rehabilitation due to multiple missing teeth, accurate diagnosis, and careful analysis, such as the patient's occlusal relationship, facial changes, and evaluation of the temporomandibular joint are essential. Orthognathic surgery is often performed for aesthetic improvement, depending on the patient's chief complaint. If it is not possible due to certain circumstances, partial aesthetic improvement can be achieved through minimal elevation of the vertical dimension. As this patient may have unexpected issues, such as temporomandibular joint disorder, oral habits like bruxism, and masticatory muscle tension, it was determined whether the patient could adjust to a reversible temporary removable partial denture. After this, the maxillary implant-supported fixed prostheses and the mandibular fixed prostheses were used to achieve stable posterior support and to partially improve the maxillary anterior esthetics. The patient was satisfied with the results both aesthetically and functionally. The prognosis is expected to be good if regular check-ups are conducted.