• Journal of Digital Convergence
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• v.15 no.10
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• pp.307-314
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• 2017

In this study, a minimum amount of the vertical occlusion was secured differently in each type of mandibular advance devices snoring and Class I malocclusion patients wore these devices. This study analyzes, after the use of devices, a different amount of the vertical occlusion results in a change of the area of upper airway by additional changes such as mandibular position, muscle changes, tongue position. The higher the vertical amount, the area of the upper airway was shown smaller, And if the patient's tongues was prevented from the distal movement, the area of the upper airway had increased, To reduce snoring, doctors should accurately diagnose patients' occlusal relationships and select a MAD snoring that is appropriate for the occlusion. The dental technician who builds the selected device should also consider design settings such as the amount of vertical occlusion, the finish lines, and the thickness of the device to increase the effectiveness of the device.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.397-406
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• 1995

The purpose of this study was to evaluate the changes of interproximal bone density by means of videodensitometer and to examine the clinical applicability of videodentitometer to assess the periodontal disease activity.Twelve interproximal sites, with periodontal pockets deeper than 5mm and vertical loss of bone on standard dental radiograph, were treated by subgingival curettage. The papilla bleeding index, the plaque index, the degree of mobility, the depth of pockets, and the level of attachment were measured. Standardized reproducible radiographs were taken by using the occlusal stent with parallelling film holder. The density of the interdental bone was measured on the radiographs by a videodensitometer at three levels: the most 'superficial' level; the 'deep' level, arbitrarily 1.5mm below: and the 'apical' level, where no bony changes were to be expected. The clinical parameter and the radiographical change were measured at initial, and 1 month, 3 months, and 6 months after treatment.The results were as follows :1. The papilla bleeding index and the degree of mobility decreased significantly until 3 months after subgingival curettage and showed the Same level in the remaining experimental periods. 2. The pocket depth mainly decreased due to the gingival recession until 1 month after treatment, but to the attachment gain after 1 month. 3. The density of the interdental bone did not show a significance increase until 1 month after treatment, but showed a steady increase throughout the 6 months of observation. 4. The close relationships were shown between the decrease in pocket depth and the gain of attachment and the improvement of bone density at 6 months after treatment.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.189-206
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• 1999

This study was performed to investigate the factors affecting muscle activity and cephalometric variables according to change of head postures. For this study, 150 patients with temporomandibular disorders and 80 dental students without any signs and symptoms of temporomandibular disorders were selected as the patients group and as the normal group, respectively. Head position to body-midline in frontal plane and upper quarter posture to body plumb line in sagittal plane were observed clinically and electromyographic(EMG) activity of anterior temporalis, masseter, sternocleidomastoideus, and trapezius on clenching were recorded with $BioEMG^{(R)}$ in four head postures, which were natural head posture(NHP), forward head posture(FHP), $20^{\circ}$ upward head posture(UHP), and $20^{\circ}$ downward head posture(DHP). Cephaloradiographs were also taken in the same head postures as in EMG taking, but that was taken only in NHP for the patient group. Cephalometric variables measured were SN angle, CVT angle, atlas inclination angle, occlusal plane angle, Me-C2 angle, pharyngeal width, occiput~axis distance, area of pharyngeal space, and cervical curvature. The data were analyzed by SAS statistical program. The results of this study were as follows : 1. Between the patient and the normal group, there were significant difference in distance from plumb line to acromion, eye-tragus angle, electromyographic activity of the four muscles, and cephalometric variables of linear measurement. 2. There was no consistent pattern of correlation between upper quarter posture, EMG activity and cephalometric variables in any case without relation to cervical curvature and head position in frontal plane. 3. Sternocleidomastoid muscle only showed variation of electromyographic activty with changes of head postures, but all the muscles did show correlation with head postures. 4. All the cephalometric variables measured in this study showed difference of mean value by head posture, and CVT angle, pharyngeal width, occiput-atlas distance, and area of pharyngeal space showed correlation between these variables with change from NHP to FHP, and from NHP to UHP.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.210-216
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• 1990

This study was performed to obtain fundamental data on temperature increases in the dental tissues irradiated by IO.opm laser radiation. For this purpose a experimental facility was established. which was composed of a CO2 laser. a shutter unit and a temperature sensing device. The temperature changes in the pulp chamber of extracted molars. during and after the laser irradiation. were measured as function of laser power. the time of irradration and the thickness of the sample. An empirical formula for the maximum temperature increases, $\DeltaT_m$ was derived from the measured data as follows; $\DeltaT_m=\alphaP\Delta\tauexp(-\betad)$$ where P. $\Delta\tau$ and d are the laser power(W). irradiation time{sec) and the thickness(mm) between pulp chamber and occlusal surface. respectively. Also a theoretical calculation model based on simplified assumptions were established and the results from the calculation were compared with the measured temperature data. A fairly good agreement was obtained.obtained.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.88-94
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• 2019

PURPOSE. This study was conducted to investigate patterns of adjacent tooth displacement in the posterior implant with interproximal contact loss (ICL) by 3-D digital superimposition method. MATERIALS AND METHODS. Posterior partially edentulous patients, restored with implant fixed partial prostheses before 2011 and suffered from food impaction of ICL between 2009 and 2011, were included. Two dental casts, at the time of delivery and at the time of food impaction in a same patient, was converted into 3-D digital models through scanning and superimposition was performed to assess chronologic changes of the dentition. Directions of tooth displacement were evaluated and the amount of ICL was calculated. Correlations between the amount of ICL and elapsed time, or between the amount of ICL and age after function, were assessed at a significance level of P<.05. RESULTS. A total number of 13 patients (8 males, 5 females) with a mean age of $65.76{\pm}9.94years$ and 17 areas (4 maxillae, 13 mandibles) were included in this retrospective study. Teeth adjacent to the implant restoration showed complex displacements but characteristic tendency according to the location of the arch. The mean amount of ICL was $0.33{\pm}0.14mm$. Elapsed time from function to ICL was $61.47{\pm}31.27months$. There were no significant differences between the amount of ICL and elapsed time, or age (P>.05). CONCLUSION. Natural teeth showed various directional movements to result in occlusal change in the arch. The 3-D superimposition of chronologic digital models was a helpful method to analyze the changes of dentition and individual tooth displacement adjacent to implant restoration.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.179-188
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• 2021

Objective: To evaluate the overall treatment effects in terms of the amount of uprighting with changes in the sagittal and vertical positions of mandibular molars after applying an orthodontic miniplate with a nickel-titanium (NiTi) reverse curve arch wire (biocreative reverse curve [BRC] system). Methods: A total of 30 female patients (mean age, 25.99 ± 8.96 years) were treated with the BRC system (mean BRC time, 10.3 ± 4.07 months). An I-shaped C-tube miniplate (Jin Biomed) was placed at the labial aspect for the alveolar bone of the mandibular incisors. A 0.017 × 0.025-inch NiTi reverse curve arch wire was engaged at the C-tube mini-plate anteriorly and the first and second premolars and molars posteriorly in the mandibular arch. Pre- and post-BRC lateral cephalograms were analyzed. A paired t-test was used to analyze the treatment effects of BRC. Results: The mandibular second molars were intrusively uprighted successfully by the BRC system. Distal uprighting with a controlled vertical dimension was noted on the first molars when they remained engaged in the BRC and the distal ends of the arch wire were laid on the second molars. The mandibular first and second premolars showed a slight extrusion. The changes in the mandibular incisors were unremarkable, while the mandibular molar angulation improved significantly. The lower occlusal plane rotated counterclockwise (MP-LOP: 1.13° ± 2.60°). Conclusions: The BRC system can provide very effective molar uprighting without compromising the position of the mandibular anterior teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.18-29
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• 2008

The purpose of this study was to compare the polymerization shrinkage of several filling methods using strain gauges. In this study, a light-emitting diode(LED) curing unit(Elipar Freeligh2, 3M EPSE, USA) and plasma arc lamp(PAL) curing unit(Flipo, LOKKI, France) were used for curing, Filtek $Z350^{TM}$(3M EPSE, USA) composite resin was used for the cavity filling. Sixty permanent bicuspid teeth, that were extracted for orthodontic treatment, were studied. The cavities were prepared on the occlusal surface and were filled using the following methods : 1) bulk filling, 2) parallel filling, 3) oblique filling The strain was recorded on the buccal, lingual, mesial and distal surfaces and the strain values were computed into stress values. The shear bond strength of each filling method was tested using a Micro Universal Testing machine. The results can be summarized as follows: 1. In the strain changes, all LED and PAL curing groups showed an increase on the buccal surface and a slow decrease as time elapsed. 2. In the strain changes of the mesial and distal surfaces, the decreases and increases were shown repeatedly and reduced as time elapsed. 3. There were no significant statistical strain changes among filling methods in the LED or PAL curing groups. 4. There were significant statistical strain changes between the LED and PAL curing groups on the buccal surface(p<0.05). 5. From the shear bond strength results, in the LED curing group, filling method 3 showed lower surface stress than filling method 1 and 2(p<0.05). In the PAL curing group, there were no significant statistical strain changes between each filling method. 6. The surface stress of each group was lower than the shear bond strength.

• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.279-294
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• 2008

This study aimed to make an analysis of the occlusion in the state of muscle fatigue produced by excessive mouth opening and clenching during the dental treatment to control the dental pain and to evaluate the sensory nerve in the muscle pain state. Most of the reasons why patients visit the dental office result in pain-either conceivably the dental origin pain or the non-dental origin pain. The dental offices have many therapeutic actions to produce the masticatory muscle fatigue for the treatment. Dental treatment with long minutes of mouth opening can cause some headaches, masticatory muscle pain and mouth opening difficulties. Patients with mastication problems who visits a dental office to alleviate pain run against another unexpected pain with other aspects. This study uses T-scan II system(Tekscan Co., USA) for the evaluation on the occlusal pattern in the experimental muscle fatigue after clenching, opening the mouth excessively and chewing gum. The occlusal contact pattern is analyzed by the contact timing, namely first, intercuspal, maximum and end point of contact. This inspection was performed at frequencies of 2000Hz, 250 Hz and 5 Hz before and after each experimental muscle pain was produced to 24 subjects who had normal occlusion without the orthodontic treatment or a wide range of the prosthesis by using $neurometer^{\circledR}$ CPT/C(Neurotron, Inc. Baltimore, Maryland, USA). The measuring sites were mandibular nerve experimental muscle fatigue respectively. This study could obtain the following results after the assessment of occlusion and sensory nerve of the experimental muscle fatigue. 1. There were the fastest expression after the excessive mouth opening in muscle fatigue and after tooth clenching in muscle pain. In the visual analog scale that records the subjective level, there was the highest scale after the clenching in the muscle fatigue in jumping off the point of pain. 2. Tooth contact time, contact force, relative contact force on the point of the first contact had no difference, and there were decreases in the contact force after the excessive mouth opening on intercuspal position point, after the excessive mouth opening and the gum chewing on the point of the maximum, and in the contact time after all the experimental muscle fatigue state on the point of the end contact. 3. There was no statistic significance in the current perception threshold before and after the experimental muscle fatigue. 4. There was no significant difference in the contact number, the maximal contact number on the point of the first contact, and the contact number after the mouth opening and gum chewing on the point of the intercuspal position and the contact number after the experimental muscle fatigue on the maximum point, and showed significant decreases. In conclusion, it was found that the occlusal pattern can cause the changes on the case of the clinical muscle weakness by intra-external oral events. It was important that the sedulous attention to details is required during dental treatment in case of excessive mouth opening, mastication and clenching.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.105-117
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• 1997

This investigation examined the effect of lateral shift of mandible from functional occlusal interference on the growth of mandible and the growth pattern of mandible shown after the removal of occlusal interference. The followings were performed with the results below : the changes in mandible and condylar cartilage were studied in the experimental group with upper right, lower left incisors cut for 2 and 4 weeks- an 4-week-old rats and the experimental group which had cut for 4 weeks and suspended for 2 weeks. 1. In the 2-week experimental group, the left mandibular length, condylar length, mandibular height and condylar area seemed smaller than those on the right and the normal group ; the right mandibular length and condylar area were smaller than the normal group. 2. In the 4-week experimental group, left condylar area was smaller than the right, but due to the quick changes in adaptability of left mandible, right and left mandibular lengths were similar. compared with the normal group, however, mandibular length and condylar area still remained small. 3. In the 6-week experimental group, the left and the right appeared similar with the mandibular length remaining still shorter than the normal group. 4. In the sagittal plane, the proliferation of the cartilage layers of the left condylar cartilage of the 2-week group appeared to have general repression compared with the right and the normal group. The right side also showed repressed growth compared with the normal group. In the 4 and 6-week groups, however, it was similar to the normal group. 5. In condylar cartilage volume, no significant difference was noted in the comparisions of left and right of the experimental group, nor in the comparison of the same sides of experimental wand normal groups. Based on the above, in case of contralateral incisal cutting in rats, it was observed that the growth of mandible and condyle of the cutting side was repressed, at the same time, the quick adaptability led to similar changes of growth in left and right mandibles. But judging from the similar phenomena throughout the whole experimental period in the changes of condylar cartilage volume in the experimental, right and left, and normal groups, the general overall growth of condylar cartilage was found unrepressed. It was also recognized that the growth of condylar cartilage can take in various directions.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.893-904
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• 1998

There are varieties of severe malocclusions, which can be treated orthodontically, but with a great deal of effort. Anterior openbite, in particular, is one malocclusion thought to be more difficult to treat, and therefore, most of them have to be corrected by means of surgical intervention. To solve these problems, numerous studies pertinent to treatment modalities have been introduced with controversies on the effectiveness of treatment. Suggested treatment modalities for anterior openbite are based directly or indirectly on the neuromuscular and morphological features and on the etiologic and/or the environmental factors. Even though the vertical relationship of the face is increased due to the growth variation, the normal occlusal relationship can be achieved by the adequate dentoalveolar compensatory mechanism, but in the case of inadequate or negative dentoalveolar compensation, openbite is likely to be present. If the skeletal dysplasia is too severe to be solved by orthodontic treatment alone, combined treatment with surgery should be done to restore the function and the esthetics of the orofacial complex. In many cases, however, orthodontic alteration of the dentition pertinent to the given skeletal pattern with the proper diagnosis and treatment planning can bring satisfactory results. The treatment changes with the Multiloop Edgewise Archwire(MEAW) therapy occurred mainly in the dentoalveolar region and showed a considerable similarity to the natural dentoalveolar compensatory mechanism. In other words, the MEAW technique allows orthodontists to produce the natural dentoalveolar compensation orthodontically. Even if an openbite is corrected by the orthodontic dentoalveolar compensation suitable for the skeletal pattern, relapse may still occur by the persisting etiologic factors which originally prohibited the natural dentoalveolar compensation. The etiologic factors should be determined at the time of initial diagnosis and should be controlled during treatment and retention.