• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.143-151
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• 2017

PURPOSE. The design of the attachment must provide an optimum stress distribution around the implant. In this study, for implant overdentures with a bar/clip attachment or a locator attachment, the stress transmitted to the implant in accordance with the change in the denture base length and the vertical pressure was measured and analyzed. MATERIALS AND METHODS. Test model was created with epoxy resin. The strain gauges made a tight contact with implant surfaces. A universal testing machine was used to exert a vertical pressure on the mandibular implant overdenture and the strain rate of the implants was measured. RESULTS. Means and standard deviations of the maximum micro-deformation rates were determined. 1) Locator attachment: The implants on the working side generally showed higher strain than those on the non-working side. Tensile force was observed on the mesial surface of the implant on the working side, and the compressive force was applied to the buccal surface and on the surfaces of the implant on the non-working side. 2) Bar/clip attachment: The implants on the both non-working and working sides showed high strain; all surfaces except the mesial surface of the implant on the non-working side showed a compressive force. CONCLUSION. To minimize the strain on implants in mandibular implant overdentures, the attachment of the implant should be carefully selected and the denture base should be extended as much as possible.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.1
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• pp.1-10
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• 1993

The purpose of this study was to evlauate the microleakage of 3 dentin bonding agents using different dentin pretreatment method under simulated physilogic pressure in cementing the porcelain laminate veneer. Noncarious 60 human maxillary molars were selected and randomly assigned to 4 groups of 15 each. The group with the margin placed on the enamel was classified as the control and the groups with the margin placed on root surface were subdivided into 3 groups according to the dentin bonding agents used. The group using All Bond 2 was classified as experimental group 1, the group using Scotchbond MP was classified as experimental group 2, and the group using Gluma was classified as experimental group 3. Roots were removed at 3mm below the cementoenamel junction, and reductions of the teeth for the porcelain laminate veneer were done on the mesial 1/2 of the buccal surface of each teeth. The pulp was extirpated and the pulp chamber was cleaned with 37% phosphoric acid for the patency of dentinal tubule. Under simulated physiologic pressure, porcelain laminate veneers were cemented to the teeth using each dentin bonding agent and luting cement. After cementation, all samples were stored at 36t in water for 24 hours and thermocycled for 1500 cycles, then immersed in 0.5% basic fuchsin solution and the teeth were sectioned longitudinally by using diamond saw and the extent of microleakage was measured. The following results were obtained, 1. Microleakage was observed in a few samples of control group but all the samples of experimental groups. 2. The control group showed the less extent of microleakage than the experimental groups. In experimental groups the experimental group 1 & the experimental group 2 showed similiar extent of microleakage and the experimental group 3 showed the greater extent of microleakage than other groups. Conclusively, practicing the porcelain laminate veneers in the clinic, although the margin of the porcelain laminate veneer should be placed on enamel, in the case that it is inevitable to place the margin of the porcelain laminate veneer on the root surface, it is recommened to use dentin bonding agents which use no dentin pretreatment or a dentin pretreatment which can leave the smear plugs.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.6
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• pp.592-596
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• 2010

The common local causes of active gingival bleeding are the vessel engorgement and erosion by severe inflammation and injury to hypervascularity lesion. Abnormal gingival bleeding is also associated with systemic bleeding disorders (liver disease, leukemia etc.). There are many conventional methods for gingival bleeding control, such as, direct pressure, packing, electrocoagulation, tight suture and application of hemostatic agents. If the continuous gingival bleeding is not stopped in spite of the all local application methods, the medical consultation should be obtained for systemic condition care and the major feeding arterial embolization. This is a case report of severe gingival bleeding and periodontitis control in a patient with liver cirrhosis and oral metastatic lesion of hepatocellular carcinoma. The bleeding lesion was placed in left buccal mucosa and gingiva of the left mandibular molars. The control methods were dental crown removal, primary endodontic drainage, gingival sulcus drainage and maxillary arterial embolization with medical consultation.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.375-384
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• 1996

The purpose of this study was to investigate the functional involvement of sympathetic nerve in the control of the microcirculation in the dental pulp with the aim of elucidation of the involvement of neuropeptides and sympathetic nerve in neurogenic inflammation. Experiments were done on the 7 cats anesthetised with sodium pentobarbital, and sympathetic nerve to the' dental pulp was stimulated electrically (10 Hz, 4 V, 1.5 ms, 3.5 mins). Ana-adrenoceptor antagonist phentolamine and a neuropeptide Y antagonist D-myo-inositol-1,2,6-trisphosphate (PP56) were injected close intra-arterially into the dental pulp without changing the systemic blood pressure. The probe of laser Doppler flowmeter was placed on the buccal surface of ipsilateral canine teeth to the stimulation, and pulpal blood flow was measured. Stimulation of the sympathetic nerve decreased pulpal blood flow by $55.24{\pm}7.74\;%$ (mean${\pm}$SEM, n = 13). Stimulation of the sympathetic nerve following the injection of the ${\alpha}$-adrenoceptor antagonist phentolamine ($0.1{\mu}g$/kg) caused decrease of pulpal blood flow by $14.35{\pm}3.43%$ (mean${\pm}$SEM, n=5). Phentolamine attenuated the sympathetic nerve-induced pulpal blood flow decrease by $74.02{\pm}9.32%$ (mean${\pm}$SEM) Stimulation of the sympathetic nerve following the injection of the neuropeptide Y antagonist PP56 (2.3 mg/kg) caused decrease of pulpal blood flow by $30.64{\pm}7.92%$ (mean${\pm}$SEM, n=6). PP56 attenuated the sympathetic nerve-induced pulpal blood flow decrease by $44.37{\pm}11.01%$ (mean${\pm}$SEM). These data provide evidences of the co-contribution of nerepinephrine and neuropeptide Y on the sympathetic nerve-induced vasoconstriction in the feline dental pulp. In addition, they show functional evidences that sympathetic nerve plays an active role in controlling the microcirculation of the dental pulp.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.1
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• pp.21-27
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• 2008

Total laryngectomy is the most useful procedure tor advanced laryngopharyngeal cancer, but it remains the major problem such as loss of voice. Voice restoration is essential for every patients who undergo a total laryngectomy. Ideal voice rehabilitation methods can resolve three factors. First, every laryngectomee can produce voice sufficient for communication, second every patient should be allowed to use both hands freely during phonation, and last, the voice restoration methods should be easy and safe without complication during and after treatment. Among various voice rehabilitation procedures during or after total laryngectomy, it can be divided electronic and pneumatic methods. In pneumatic methods, there are also divided both pulmonary air and non-pulmonary air methods. The non-pulmonary air methods include esophageal speech, buccal speech, and pharyngeal speech. Pulmonary air methods are divided into surgical and non-surgical such as pneumatic speech aid. In the surgical methods, there are neoglottic operation, tracheopharyngeal shunt, and tracheopharyngeal shunt operations. Recently, tracheoesophageal shunt with or without prosthesis are being recognized the most effective method. Blom-Singer low pressure prosthesis, Panje button, and Provox are well known types of prosthesis in the tracheoesophageal shunt operation. Amatsu method is a kind of famous tracheoesophageal shunt method without using prosthesis. Authors tried to review the published articles for evaluation of effectiveness and problems of tracheoesophageal shunt operation with or without prosthesis. In conclusion, indwelling type of prosthesis and pharyngeal myotomy and plexus neurectomy are recommended for higher success rate during tracheoesophageal puncture procedure. More over, Amatsu method is also one of the recommended voice rehabilitation procedure during total laryngectomy. In this situation, pharyngeal myotomy and plexus neurectomy may be helpful for better fluent communication.

• The Journal of Advanced Prosthodontics
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• v.6 no.6
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• pp.444-450
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• 2014

PURPOSE. To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS. 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ${\times}200$ magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS. Overall mean gap values for the three groups was found to be $155.93{\pm}33.98{\mu}m$ with Anatomical Occlusal preparation design having the least gap value of $139.23{\pm}30.85{\mu}m$ showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION. Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.639-646
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• 2004

Dental phobia is the most prevalent fear in all age groups, across gender, and in all countries. One of the primary identified sources is the fear of dental injections in the dental phobia or the high dental fear and anxiety groups. The purpose of this study was to clinically evaluate the computer controlled anesthetic device and to compare it with traditional methods of dental anesthetic delivery. Fifty(mean age : 25.6 yrs) systemically and periodontally healthy volunteers participated in this study. The subjects were given contralateral buccal and palatal injections. One side was injected with the computer-controlled anesthetic device with a microprocessor and an electric motor to precisely regulate flow rate during administration : The experimental group. The control side was injected with a standard manual syringe, in which flow rate and pressure are operator-dependent and can't be controlled accurately : The control group. The subjects described their perceived pain experiences with two subjective scales. The results of this study were as follows: 1. The computer-controlled anesthetic device was significantly less painful than conventional syringe injection 2. The female subjects reported more pain than the male subjects. But, there were no statistical differences. 3. The anesthetic effect of both methods did not show any difference. In this study, it may be concluded that pain levels decreased significantly when the computer-controlled anesthetic device was used.

• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.340-345
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• 2009

There are a number of situations where the oral mucosa can be sucked or pressed to produce relatively banal but clinical distinctive changes. The labial and buccal mucosa and tongue may develop protuberances in areas where a tooth is missing or extra space is present. The mucosa is pressed and sucked into these spaces, thus leading to the development of a fibrous hyperplasia. This case report describes the management of fibrous hyperplasia in oral mucosa. Fibrous hyperplasia can be formed by habitual pressure or suction in oral mucosa. Treatment of fibrous hyperplasia consists of simple excision and, if feasible, elimination of the cause. And habit control is a important factor for preventing recurrence.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.1
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• pp.34-42
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• 2004

The appropriate care to the dental emergency patients is much important in the aspect of community dental service. To attain such a purpose, the sacred duty of the training of oral and maxillofacial surgeons is required. So, a retrospective study on the characteristics of dental injuries and diseases in emergency care unit will be very meaningful. This study was carried by reviewing the charts and radiographic films of 3,394 patients, treated for dental emergency at Wonju Christian Hospital, Republic of Korea, from January 1, 1993 to December 31, 2002. All patients were classified to 6 groups including trauma, toothache, infection, hemorrhage, TMJ disorder and the others. The clinical characteristics of diseases and treatment modalities according to each group were analyzed. The trauma (73.9%) was the most frequent cause in dental emergency patients, and acute toothache, odontogenic infection, oral hemorrhage, and TMJ disorder were next in order. Gender prediction was male (68%), there were many patients on May and December in the monthly frequency, and the most frequent age group was from 0 to 9 years. In the trauma group, male (68.6%) was predominant, and soft tissue injuries and primary closures were the most frequent type of injury and treatment. In jaw fractures, traffic accidents were the most cause and the weakest site was mandibular symphysis area, and mandibular angle, condyle, and body area were next in order. In the acute toothache group, the cause was dental pulpitis mostly and treatment for that was drug administration mainly. Buccal space abscess in infection group had the largest incidence (24.5%), and common treatments were incision and drainage and medications. In the hemorrhage group, a major cause was postoperative bleeding (60.3%) and hemostasis was obtained by pressure dressing, curettage and suture. For the TMJ disorder group, the peak incidence (63.8%) was shown in the post-traumatic myofascial pain dysfunction syndrome and its primary care was medication such as analgesics and sedatives. In the other group, the various specific symptoms were complained due to acute sialadenitis, trigeminal neuralgia, acute stomatitis, chemical burn, terminal stage neuritis of head and neck cancer, and foreign body aspiration. In conclusion, for the rapid and proper care of the emergency dental diseases, well-trained education should be presented to the intern and resident course of oral and maxillofacial surgery. And it is demanded that oral and maxillofacial surgeons must be prepared in knowledge and skill for such emergency care.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.1
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• pp.58-64
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• 2012

Purpose: Dental emergencies vary from toothaches to oral and maxillofacial traumas. Because the number of dental emergency cases has increased recently, we analyzed characteristics of patients seen during the last 2 years, in an effort to find a trend. Methods: This study was carried out with emergency room patients visiting the Department of Oral and Maxillofacial Surgery from 2009 to 2010. Results: The total number of patients studied was 1,162; the ratio of males to females was 1.73:1. The most frequent age group was 0 to 9 years, followed by 20 to 29 years. Trauma (58.7%) was the most frequent cause followed by acute toothache, oral hemorrhage, infection, and temporomandibular (TMJ) disorder. In the trauma group, injuries of soft tissue and alveolus were prevalent. The most common causes of soft tissue injury were falls, safety violations and assault. The highest incidence of emergencies was seen in patients 0 to 9 years old (41.8%). The most common causes of jaw fracture were falls, assaults, and traffic accidents in that order. In the acute toothache group, most patients had pulpitis (41.2%). In the infection group, most had buccal space abscesses (40.0%). In the hemorrhage group, post-operative bleeding cases (80.5%) were the majority, and hemostasis was obtained mostly by pressure dressings. For the TMJ disorder group, masticatory muscle disorder (65.4%) was more common than TMJ dislocation. Conclusion: In this study, trauma was the most frequent reason for patients who visited the emergency room. However, acute toothache, hemorrhage, infection and TMJ disorders were also seen frequently. Dental emergency patients could be better treated by understanding patterns of dental emergencies and performing proper diagnoses.