• Journal of the korean academy of Pediatric Dentistry
• /
• v.46 no.4
• /
• pp.343-352
• /
• 2019

Abnormal orofacial functions such as lip incompetency in the period of growth and development can cause morphological anomalies of the craniofacial complex. Therefore, it is crucial to make an early diagnosis based on the evaluation of the myofunctional conditions, and to make appropriate treatment plans. The objectives of this study were to quantitatively evaluate the standard lip closing force (LCF) of each age in the elementary school children, and to evaluate the relationships between LCF and affecting factors. The sample consisted of 765 children who were 7 - 12 years old in Jeonju city. Clinical examination about occlusal conditions and lip competency, and LCF measurement were performed by a single examiner. LCF was measured three times for each children with the LCF measuring device. The LCF was correlated positively with age in both sexes. The distribution of LCF groups was correlated significantly with Angle's classes and lip competency (p = 0.016, 0.004). The proportion of children with high LCFs was greater in the "competent lip" group, whereas the proportion of those with low LCFs was greater in the "incompetent lip" group.

• The korean journal of orthodontics
• /
• v.50 no.2
• /
• pp.120-128
• /
• 2020

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R^® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

• Korean Journal of Cleft Lip And Palate
• /
• v.12 no.1
• /
• pp.21-32
• /
• 2009

Generally, an adult cleft lip or/and palate patient shows some amount of maxillary deficiency due to limitation of bony growth caused by heavy scars resulted from previous operations such as a cheiloplasty and/or a palatoplasty at an early child age. To solve the problem, advancement of the maxilla is usually required during orthognathic surgery. However, severe tensional force resulted from heavy scars on the palate and/or the lip, as well as the bony defect at the cleft area limited sufficient advancement of the maxillary segment and finally caused relapse of the reposed maxilla. Therefore, distraction osteogenesis of the maxilla was introduced for the successful maxillary advancement inthose kinds of patients. As both hard and soft tissues can be simultaneously and gradually extended with this technique, tensional force caused by heavy scars opposed to forward movement of the maxilla can be reduced to an extent not to develop severe relapse of the advanced maxilla. Since distraction osteogenesis of the maxilla was applied as one of standard protocols for the treatment of the patients with severe maxillary hypoplasia dueto cleft lip and/or palate, the devices for the distraction was improved to control the vectors of distraction with better and more stable. We have treated a 23-year-old male cleft patient with a severe maxillary hypoplasia using a newly developed a maxillary distraction device and a RP model for a pre-operative simulation surgery. As a result, we could successfully move the maxilla as we designed pre-operatively and also reduce much of operation time. Therefore, we report of the case to share our experience with colleagues.

• Korean Journal of Cleft Lip And Palate
• /
• v.7 no.1
• /
• pp.1-16
• /
• 2004

In the recent time, early correction of the congenital anomalies has become the focus of contemporary cleft lip care, The reason of that is mostly psychologic factor of children are respected, Although the propound object of lip adhesion is not esthetic improvement, that able to satisfy sufficiently parents of cleft children, In the unilateral or bilateral clefts, a preliminary lip adhesion has been advocated as a mean of narrowing the cleft at an early phase, of improving the nasal contour, of molding the alveolar arch, and of easing and improving the result of a definitive lip repair. The present study was earned out to investigate the effect of lip adhesion. We performed the Millard's high-half underminded adhesion and Seibert's lip adhesion followed by modified Millard's cheiloplasty for five infants had unilateral complete cleft lip. The lip adhesion reduced the actual deformity by molding the maxillary alveolar segments into better relationship and allows a easy cheiloplasty so that led to more perfect final lip result, Both Millard's high-half underminded adhesion and Seibert's lip adhesion were available methods to adhere a wide cleft lip, Especially, Seibert's lip adhesion had more advantages such as enhancement of the force of adhesion, correction of the deviated columella and acquirement of the esthetic upper lip continuity. These results suggest that the lip adhesion followed by cheiloplasty for wide unilateral complete cleft lip patients provide more favorable final result by molding the maxillary alveolar segments into better relationship.

• Journal of Advanced Marine Engineering and Technology
• /
• v.15 no.4
• /
• pp.29-45
• /
• 1991

Lip type stern tube sealing systems have used in almost all the middle or large ships which are being constructed in these days. It seems that the pressure fluctuation of the seal ring interspace, the cross-section profile and the materials quality of the seal rings have great effects on the sealing fuction of this sealing system. In this paper, the mechanical movement of lip seal ring which plays the most important role in stern tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. Using the finite element method for the axi-symetric object which receives the torsional load, the displacement and stress analysis of the seal rings, and also the possibility of crack occurance is checked by theoretical analysis. If the force which seal ring lip periphery receives is too small, there will be the possibility of leakage caused by the pressure fluctuation of the seal ring interspace, and if this force is too large, the frictional force between the seal ring and the liner will become problematical. The possibility of leakage caused by hardening of seal ring materials and creep phenomena of tested seal rings are also examined. The trial seal rings were designed and manufactured using the program of displacement and stress analysis developed in this study and the experimental apparatus to test the trial seal rings was also designed and manufactured. This trial seal rings were fitted in the experimental apparatus which was made in the same form as an actual stern tube. The one side of this apparatus was filled with sea water and the other side of it was filled with the lubricating oil. The leakage of oil and sea water was checked and the temperature was measured, rotating the propeller shaft at the constant velocity by D.C. motor. It was proved that the trial seal rings made in Viton rubber functioned excellenty but the trial seal rings made in N.B.R. rubber had problem in its durability.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.4
• /
• pp.303-310
• /
• 2019

The purpose of this study was to compare the oralmyofunctions (occlusal force, tongue pressure, lip force) of adults and elderly people. And analyzed the factors affecting oral health related quality of life and dysphagia. The study was conducted on 73(over 20 years of age) Residing in Daejeon and Nonsan From December 2017 to May 2018. The data was analyzed using one-way ANOVA, pearson's correlation and multiple regression. The masticatory strength of each age group evaluated the right and left posterior occlusal forces. the elderys group (8.93, 10.80) were lower than adults group(12.51, 14.61) and middle age group(11.63, 14.75)(p>0.05). The tongue pressure was statistically significant lower in eldery group(37.43) than the adult group(60.55), middle-aged group(50.61) (p=0.000). In addition lip force was significantly lower in eldery group(8.57) than adult(12.01), middle-aged(11.37)(p= 0.000). The tongue pressure was positively correlated with the number of natural teeth(r=.566, p<.05), and the lip force (r=.497, p<.05). The quality of life quality related to oral health and dysphagia was tongue strength(p<0.05). It is necessary to recognize the risk of declining oral muscle function caused by aging. especially tongue strength is associated with quality of life and dysphagia. In order to improve the quality of life related to oral health in the aged society, the necessity of regular oral administration and oral muscle training was proposed.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.6
• /
• pp.84-90
• /
• 2010

This paper presents the shape optimization process for the automotive wheel bearing seal lip using the finite element method and the response surface method. First, to predict performance of the bearing seal lip, we used the non-linear finite element analysis. And then, we compared the analysis results with the test results to verify the finite element model. The objective function in optimizing process was obtained from results of the mud slurry test, which is one of many tests for evaluating performance of wheel bearing. After the mud slurry test for the four models which have the similar cross-sectional shape, we measured the wear area of the seal lip and the moisture content in grease. The objective function has been chosen by comparing the results of mud slurry test and characteristics of seal lip, such as contact force, contact area, contact pressure, and interference. Finally, within limited design parameters, we suggested the optimized shape of seal lip, which is expected to improve the wear and the sealing effect of it.

• Korean Journal of Cleft Lip And Palate
• /
• v.4 no.2
• /
• pp.45-50
• /
• 2001

Recents reports have demonstrated that force and direction is important during mandibular distraction osteogenesis. The purpose of this study was to evaluate the resistant force of internal pterygoid muscles and inquire into relationship between internal pte'Ygoid muscles and cephalometric parameters. Eighty four patients with class III malocclusion underwent bilateral sgittal splitting of ramus with intraoral vertico-sagittal ramal osteotomy. A spring scale were used for measuring for resistence of internal pterygoid mescles after splitting of ramus. Skeletal-dental cephalometric analysis was made following statistic package was used for correlation between resistence and cephalometric parameters. The resistant force of right internal pterygoid muscle was greater than left muscle in Korean with class III malocclusion and the force had a linear regression relationship with facial depth (distance between nasion and gonion). The results suggested that facial depth has significant correlation of the resistance of internal pterygoid muscle (p<0.05).

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.3
• /
• pp.83-88
• /
• 2010

This study aimed to enhance the durability by distributing the stress concentration at the contact and increasing the mechanical characteristics, as well as by changing the surface shape for LIP in the low-pressure seal among oil seals installed to the power steering of automotive. Accordingly, results were derived from comparisons and reviews with oil seals under the existing mass production by carrying out the performance tests after designs and productions are done with the addition of embo shapes on the surface of LIP in the low-pressure seal. As a result of this study, it has been identified that the durability of oil seals with the addition of embo shapes was enhanced with higher radial force and less variation in the internal diameter for the LIP. In addition, it was seen that the sealing ability for those oil seals is superior to the existing oil seals as their rotational torque values are less than those of the existing oil seals.

• 연구논문집
• /
• s.26
• /
• pp.25-32
• /
• 1996

Water seals are used in a washing machine to seal rotating shafts and to prevent the penetration of dust, dirt or water from the outside. The design parameters of water seals, that were the location of the garter spring, the angle of the seal lip, and the interference, were investigated by the computer simulations using the hyperelastic non-linear large deformation finite element analysis code. The maximum contact stress and the distribution of stress on the seal lip were obtained for various type of water seals. The best type among the several investigated seals was selected considering the contact force and the sealing performance.