• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.225-236
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• 2001

It is widely accepted that the shape and structure of bone are closely related to the activity of attached muscle. Numerous clinical and animal experimental studies indicated the significant effects of masticatory muscle function on maxillofacial morphology. Recently, the development of ultrasonography has spread throughout different fields of medicine. In the clinical examinations, ultrasonography is a convenient, inexpensive technique to apply with accurate and reliable results. The aim of this study is to assess the thickness of the masseter muscle and its correlation to maxillofacial skeleton by examining 35 male and 15 female dental students at Kangnung National University. The masseter muscle thickness of the subjects were measured by ultrasonographic scanning with a 7.5MHz linear probe, and their maxillofacial morphology were investigated by lateral cephalometric radiographs. The relationship between the masseter muscle thickness and maxillofacial morphology of normal adult was statistically analyzed, and the following results were obtained. 1. The average thickness of male masseter muscle was 13.8${\pm}$1.71mm in the relaxed state and 14.8${\pm}$1.77mm at maximal clenching state, while that of female was 11.6${\pm}$1.58mm and 12.4${\pm}$1.47mm, respectively. Ethnic difference in thickness of the masseter muscle and maxillofacial skeleton was found when the results of many researchers were compared with those of this study. 2. The thickness of the masseter muscle in both sexes increased significantly at maximal clenching state than in relaxed state(P<0.05). 3. The masseter muscle thickness of male was greater than that of female both in the relaxed state and maximal clenching states(P<0.05). 4. In males, the thickness of the masseter muscle was negatively correlated with the mandibular plane angle and positively correlated with the mandibular ramus height and anterior cranial base length(P<0.05). It may suggest that the male with thicker masseter muscle has smaller facial divergence. 5. No significant correlation was found between the masseter muscle thickness and maxillofacial morphology in females(P<0.05). Therefore, these data suggest that ultrasonography can add valuable information to the conventional examinations of masseter muscle function.

• Journal of Oral Medicine and Pain
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• v.16 no.1
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• pp.25-32
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• 1991

The author studied the changes of electromyographic activities of the masseter and anterior temporal muscles during maximal clenching before and after stabilization splint wearing. It also studied the changes of the symmetry of the muscle activity during maximal clenching. For this study, 15-healthy-female-students were selected. The obtained results were as follows : The EMG activities of right and left anterior temporal muscles and right masseter muscle during maximal clenching immediately after wearing of the stabilization splint were not changed compared with before wearing of the stabilization splint. The EMG activities of right and left masseter and anterior temporal muscles during maximal clenching were significantly increased after 1 week and 4 week-use of the stabilization splint(p<0.01). The asymmetric indices of the EMG activities of right and left masseter and anterior temporal muscles during maximal clenching immediately after wearing of the stabilization splint were not changed compared with before wearing of the stabilization splint. The asymmetric indices of the EMG activities of right and left anterior temporal muscles during maximal clenching were significantly decreased after 1 week and 4 week use of the stabilization splint(p<0.01). and that of masseter muscles showed a decreased tendency but there were no significant differences(p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.195-204
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• 1987

The purpose of this study was to investigate the effect of occlusal splints on the masseteric silent period and the changes of the masseteric silent period after experimental bruxism with occlusal splints. In nine subjects, anterior occlusal splints were fabricated. The jaw-jerk reflex was induced by tapping over mandibular symphysis area with solenoid driven hammer and electromyogram of left masseter muscle was recorded. In the recorded electromyogram of left masseter muscle the silent period duration was measured. This procedure was done before insertion of anterior occlusal splints, after insertion of anterior occlusal splints, after 30 min experimental bruxism with anterior occlusal splints, and 3hr after removal of anterior occlusal splints. The result were as follows; 1. The mean silent period duration was increased after insertion of occlusal splints compared with the mean silent period duration before insertion of occlusal splints. 2. There was no change of the mean silent period duration after 30 min experimental bruxism with occlusal splints compared with the mean silent period duration after insertion of occlusal splints. 3. 3hr after the removal of occlusal splints, the mean silent period duration showed no difference from the mean silent period duration before insertion of occlusal splints.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.120-125
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• 2018

Conventional denture impression techniques have limitations for edentulous patients with severe alveolar bone resorption and can cause problems from excessive border extension. Especially when a patient has movable tissue it is difficult to make accurate impression, thus might interrupt stable seating of complete denture. Fabrication of complete denture using closed mouth technique for edentulous patient with severe ridge resorption is thought to provide better stability and retention. In this case, an 86-year-old patient had both edentulous jaws with epulis fissuratum on maxillary anterior ridge and severe mandibular ridge resorption. Thus, tentative vertical dimension was determined by using Centric trayand individual tray attached with gothic arch tracer was fabricated. Complete denture was fabricated using closed mouth technique and the patient was satisfied with better stability and retention of the complete denture.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.71-79
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• 2022

Excessive crown height space increases can cause crestal bone loss and screw loosening after prosthesis is placed. Milled bar and implant overdenture can be used as a treatment method for partially edentulous patients who have severe alveolar bone loss and excessive crown height space. Milled bar can provide primary splinting effect and stability between implants. Also, milled bar with additional retention device such as Advanced Dental Device-Treatment Of Choice (ADD-TOC) and magnet can provide additional retention force for implant overdenture. In this case, the patient has a partially edentulous mandible that has severe alveolar bone loss and multiple number of teeth loss after excision due to leiomyosarcoma. Because of the long-term loss of mandibular molars, the opposing teeth were extruded. Maxillary left molars were corrected to the occlusal plane through molar intrusion, and mandibular left molar region were treated with implant overdenture, using milled bar with ADD-TOC and magnet after implant placement. The clinical result was satisfactory on the aspect of esthetic and masticatory function.

• The korean journal of orthodontics
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• v.40 no.4
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• pp.276-287
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• 2010

This case report describes the treatment of a 23-year, 8-month-old female patient with a Class II malocclusion who showed severe bidentoalveolar protrusion and anterior crowding. The treatment plan consisted of extracting all the first premolars, decrowding and en masse retraction of the upper six anterior teeth and lower anteriors. The upper C-plate placed in the midpalatal area combined with lingual sheath fixtures were used as substitutes for posterior anchorage teeth during upper anterior retraction. Preadjusted brackets (0.022-inch) were used for upper anterior decrowding. A 0.9 mm diameter stainless steel lever-arm soldered to the main arch wire facilitated controlled retraction of upper anteriors. The upper and lower dentition was detailed using a tooth positioner during the finishing stage. Correct overbite and overjet were obtained by decrowding and retraction of the upper six anterior teeth into their proper positions. Use of the C-plate and lingual appliances provided ideal anchorage to enhance the improvement in facial balance. The active treatment period was 19 months. The treatment result was stable 13 months after debonding.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.4
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• pp.327-336
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• 2007

Purpose This study was planned to compare and evaluate the stability of implant using $Osstell^{TM}$ and Osstell $Mentor^{TM}$. Material and methods Artificial bone and RBM(resorbable blasting media) surface blasted implants(Osstem US II, SS II implants - diameter: 4mm, length: 13mm) were used. To measure the stability of installed implants, $Osstell^{TM}$ and Osstell $Mentor^{TM}$ were used. In the first experiment, five implants were installed in D1(external type implants) and D3(internal type implants). In the second experiment, 4 internal type implants were divided in two groups and installed in D1 artificial bone with different depth. In the third experiment, two external implants were installed in D1 and D3 artificial bone each and two internal implants were installed in D1 and D3 artificial bone. In all groups, their stability were measured by $Osstell^{TM}$ and Osstell $Mentor^{TM}$. Results In all groups, $Osstell^{TM}$ and Osstell $Mentor^{TM}$ both showed reliable measurement values. The value difference between $Osstell^{TM}$ and Osstell $Mentor^{TM}$ was observed but the difference was small and clinically acceptable. Conclusion These results suggest that the use of Osstell $Mentor^{TM}$ has clinical relevance in the assessment of implant stability.

• Journal of Oral Medicine and Pain
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• v.32 no.4
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• pp.441-447
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• 2007

Internal derangement of the temporomandibular joint(TMJ) is defined as an abnormal relationship of the articular disc to the condyle. Mandibular manipulation is one of the conservative treatments to be considered first to manage the patients with anterior disc displacement without reduction. Mandibular manipulation is used to increase articular mobility and to restore the displaced disc into an anatomically normal position. While Farrar's technique has been popularly used, Minagi et al., Mongini and Suarez introduced the manipulation technique conducted by the patients themselves. But there is no study on the efficacy of self-manipulation technique, comparing with conventional one. The aim of this study was to investigate the efficacy of the conventional and self-manipulation technique, which was modified to complement the previously described technique by Minagi et al., in the treatment of patients with anterior disc displacement without reduction. TMD patients, who visited Department of Oral Medicine of Seoul National University Dental Hospital from December, 2002 to November, 2004 and were diagnosed as anterior disc displacement without reduction by TMJ magnetic resonance imaging (MRI) were enrolled. Conservative treatments including physical therapy, exercise, behavioral therapy, stabilization splint therapy, and manipulation therapy were done to every single patient until the symptomsimproved enough to discharge the patient. The charts were reviewed retrospectively according to the type of manipulation. In the results, patients whose maximum mouth opening was more than 40 mm was higher in the self-manipulation group(69.9%) than in the conventional manipulation group(42.9%). But difference between two groups was not significant. According to the fact that we decided to discharge the patients whentheir mouth opening increased to more than 40 mm and subjective symptoms such as pain and discomfort were improved as well, treatment period of discharged patients was significantly shorter in the self-manipulation group($29.2{\pm}12.3$ weeks) than in the conventional manipulation group ($61.0{\pm}38.0$ weeks) (p<0.01). In conclusion, in the treatment of TMD patients with anterior disc displacement without reduction, the self-manipulation technique which is performed by patients themselves is an effective treatment modality for increasing the range of mouth opening and shortening the total treatment period.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.167-175
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• 2020

The purpose of this study was to determine whether the palatal rugae could be used as an appropriate reference area for serial model superimposition following Rapid maxillary expansion(RME) and facemask treatment. A total of 52 pediatric patients who had undergone RME and facemask treatment were selected. Palate and palatal rugae in the pre- and post- treatment casts from the patients were measured. In spite of dentoalveolar changes occurred by RME and facemask, anteroposterior changes in palate and palatal rugae were not significant. Anatomical changes of palate and palatal rugae were mostly shown in the transverse dimension. The soft tissue of the palatal rugae stretches in adaptation to hard tissue movement. Among the evaluated landmarks, the medial point of the third palatal rugae seemed to be the most stable. The observed alterations in the palatal rugae demonstrated the potential of medial points of third palatal rugae as a reference point in model superimpositions to evaluate dental movement within the maxillary arch following RME and facemask treatment.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.67-78
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• 1996

This study was performed to compare the TMJ sounds by means of vibration-related items by Sonopak such as integral, high integral, above 300/(0-300) ratio, peak amplitude, peak frequency and median frequency before and after occlusa1 splint therapy as well as counselling, physical modalities. For this study 22 patients with craniomandibular disorders (CMDs) were selected and examined by routine diagnostic procedure for CMDs including Transcranial and Panoramic radiographs and were classified into 3 CMDs subgroups : disc displacement with reduction, disc displacement without reduction, and degenerative joint disease. Visual analogue scale (VAS) about joint sound was recorded during treatment period and VAS treatment index (VAS Ti) was calculated from the VAS data and treatment duration. The author evaluated and compared treatment results by several parmeters such as symptom duration, timing of joint sound, parafunctional habits, trauma, and diagnostic classification. The obtained results were as follows : 1. Before the treatment, the highest value of peak amplitude was observed in disc displacement with reduction group and value of median frequency was highest in degenerative joint disease group. In addition the highest values of peak frequency and ratio ware observed in degenerative joint disease group, though they were not significant. Furthermore the lowest value of high integral was observed in disc displacement without reduction group and though it was not significant, value of integral was lowest in that group. 2. Among 3CMDs subgroups disc displacement with reduction group showed the significantly decreased value of high integral and degenerative joint disease group had the significantly decreased value of integral after conservative treatment including occlusal splint therapy. Conclusively conservative treatment including occlusal splint therapy vay be effective in the treatment of CMDs including TMJ sound. 3. Fair prognosis for conservative treatment was observed in acute group under 6 months than chronic group, 6 months over in symptom duration but there was no statistical difference. The result for conservative treatment was observed slightly poor in subjects with bruxism, clenching, unilateral chewing habit and trauma history but there were no statistical differences.