• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.260-264
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• 2013

Calcium hydroxide root canal filing paste (vitapex) is widely used as canal filling paste for infected canal. However, chemical burn is possible because of the high alkali base of calcium hydroxide. A 57-year old woman was admitted to our clinic for consistent dull pain and paresthesia in the left upper lip, zygoma and buccal cheek area, which developed during an endodontic treatment of the left lateral incisor. Radiographic finding showed radiopaque material, which exits from the left incisor root apex, and was within the left canine and first premolar buccal soft tissue. The overfilled Vitapex extended to the soft tissue was surgically curetted. The result of the surgical curettage was favorable. Though slight hypoesthesia on the upper lip was still remained, paresthesia on zygomatic and buccal cheek area was completely recovered. As far as we know, this is the first case report of infraorbital nerve damage from overfilled Vitapex material.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.7-20
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• 1987

The author studied the acute reaction of cobalt-60 irradiation to buccal mucosa in rats and difference of the effects of single versus fractionated exposure. 195 Sprague Dowley strain rats, weighing about 120gm, were used in this experiment. 3 rats served as controls and the remaining 192 rats were divided into six groups of 32 rats each. Experimental group Ⅰ, Ⅱ, Ⅲ were received a single dose of 15Gy, 16.5Gy, 18Gy and group Ⅳ, Ⅴ, Ⅵ were received two equal sized fractionated dose of 9Gy, 9.75Gy, 10.5Gy at 4 hour intervals, respectively. The experimental groups were irradiated with cobalt-60 teletherapy unit, Picker model 4M 60 (Field size, 12x5 cm, SSD, 50㎝, Dose rate, 222cGy/min, Depth, 1㎝). The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and the changes of the irradiated buccal mucosa were observed by electron and light microscopy. The results were as follows: 1. A single exposure was more damaging than fractionated exposure, and as the radiation dose increased, the changes of cell organelles became faster, but the healing of radiation-induced damage in fractionated exposure was faster than in single exposure. 2. The radiation-induced changes of the basal cells were the most prominent in 18Gy-single exposure group, and the least in 18Gy-fractionated exposure group. 3. Electron-microscopically, there appeared nuclear changes, swelling of mitochondria and rough endoplasmic reticulum, decrease of free ribosome, presence of vesicles, widening of intercellular space, and loss of basal lamina. The early remarkable changes were partly loss of nuclear membrane and swelling of mitochondria. 4. Light-microscopically, derangement and pyknosis of basal cells, hydropic changes of spinous cells, enlargement of granular cells, indistinctness of basement membrane, and proliferation of epithelium were observed.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.217-230
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• 1997

The location of the mandibular canal and the cortical thickness of the mandible is important in the practice of dentistry. This study was performed on twenty chosen dry mandibles, which were of adults and included fully erupted premolars and molars. The purpose of this study was to evaluate the location of the mandibular canal and the cortical thickness of the mandible on computed tomograms and to aid in the surgical treatment plans. The obtained results were as follows; 1. The horizontal distance between the mandibular canal and the buccal external border was 6.6±0.9mm on Somesial root of the first molar), and it was increased posteriorly. The horiwntal distance between the mandibular canal and the lingual external border was 4.1±1.lmm on S/sub 0/, and it was decreased posteriorly. 2. The vertical distance between the alveolar crest and the mandibular canal was 16.9±1.6mm on S/sub 0/, and it was decreased posteriorly. The vertical distance between the inferior border of mandible and the mandibular canal was 8.8±1.3mm on S/sub 0/, and it was increased anteriorly and posteriorly. 3. The thickness of the buccal cortical plate was 2.2±0.4mm on S/sub 0/. and it was increased posteriorly. But, that of the lingual cortical plate was 2.0±0.6mm on S/sub 0/ and it was decreased posteriorly. 4. The area of the buccal cortical plate was 66.5±1.0mm² on S/sub 0/. and it was increased posteriorly. But, that of the lingual cortical plate was 65.8±0.9mm² on S/sub 0/ and it was decreased posteriorly.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.286-318
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• 1992

The objective of preventive dentistry is the maintenance of a healthy dentition for the life of a patient. Unfortunately, if an individual has not received the benefit of a comprehensive program of preventive dentistry and has finally reached the edentulous state, as a consequence, he receives a set of complete denture. Dentures are mechanical devices and subject to the principles of mechanics. In some cases, the general health and nutritional status of the patient are felt to be the causative factors. But, the most important thing in residual ridge resorption is felt to be caused by the unequal distribution of functional forces. This study was to analyze mandibular stresses of complete denture occlusion by three dimensional finite element method. The results were as follows ; 1. As deformation and stress distribution of the complete denture of the mandible were concentrated on the upper lingual side of the mandible, alveolar ridge resorption of the mandible occurred from lingual side to labio-buccal side. 2. Analyzing by three dimensional F. E. M., the mandible is a very effective form for tolerating stress and deformation biomechanically. 3. According to the concentration of stress distibution in the upper buccal side of the lower posteriors, buccal shelf area must be a primary stress bearing area in the lower complete denture. 4. Lower complete denture moved horizontally to the balancing side under lateral occlusal force. 5. Bilateral balanced occlusion should be constructed in the complete denture for denture stability, especially in the protrusive movement. 6. Physical property of the denture base material was as important for stress distribution in the denture base as or even more than that in the mandible. 7. Impression technique is very important because of most of stress was concentrated between them due to close contact of the mandible and the denture base.

• The korean journal of orthodontics
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• v.48 no.2
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• pp.81-89
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• 2018

Objective: The aim of this study was to evaluate the stress distribution and displacement of various craniofacial structures after nonsurgical rapid palatal expansion (RPE) with conventional (C-RPE), bone-borne (B-RPE), and miniscrew-assisted (MARPE) expanders for young adults using three-dimensional finite element analysis (3D FEA). Methods: Conventional, bone-borne, and miniscrew-assisted palatal expanders were designed to simulate expansion in a 3D FE model created from a 20-year-old human dry skull. Stress distribution and the displacement pattern for each circumaxillary suture and anchor tooth were calculated. Results: The results showed that C-RPE induced the greatest stress along the frontal process of the maxilla and around the anchor teeth, followed by the suture area, whereas B-RPE generated the greatest stress around the miniscrew, although the area was limited within the suture. Compared with the other appliances, MARPE caused relatively even stress distribution, decreased the stress on the buccal plate of the anchor teeth, and reduced tipping of the anchor teeth. Conclusions: The findings of this study suggest that the incorporation of miniscrews in RPE devices may contribute to force delivery to the sutures and a decrease in excessive stress on the buccal plate. Thus, MARPE may serve as an effective modality for the nonsurgical treatment of transverse maxillary deficiency in young adults.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.314-323
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• 2020

Objective: To identify the available evidence on the effects of rapid maxillary expansion (RME) with three-dimensional imaging and provide meta-analytic data from studies assessing the outcomes using computed tomography. Methods: Eleven electronic databases were searched, and prospective case series were selected. Two authors screened all titles and abstracts and assessed full texts of the remaining articles. Seventeen case series were included in the quantitative synthesis. Seven outcomes were investigated: nasal cavity width, maxillary basal bone width, alveolar buccal crest width, alveolar palatal crest width, inter-molar crown width, inter-molar root apex width, and buccopalatal molar inclination. The outcomes were investigated at two-time points: post-expansion (2-6 weeks) and post-retention (4-8 months). Mean differences and 95% confidence intervals were used to summarize and combine the data. Results: All the investigated outcomes showed significant differences post-expansion (maxillary basal bone width, +2.46 mm; nasal cavity width, +1.95 mm; alveolar buccal crest width, +3.90 mm; alveolar palatal crest width, +3.09 mm; intermolar crown width, +5.69 mm; inter-molar root apex width, +2.85 mm; and dental tipping, +3.75°) and post-retention (maxillary basal bone width, +2.21 mm; nasal cavity width, +1.55 mm; alveolar buccal crest width, +3.57 mm; alveolar palatal crest width, +3.32 mm; inter-molar crown width, +5.43 mm; inter-molar root apex width, +4.75 mm; and dental tipping, 2.22°) compared to pre-expansion. Conclusions: After RME, skeletal expansion of the nasomaxillary complex was greater in most caudal structures. Maxillary basal bone showed 10% post-retention relapse. During retention period, uprighting of maxillary molars occurred.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.2
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• pp.85-99
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• 2004

Purpose: This study observed the changes in the telomerase activity, it's developmental regulation, PCNA expression, and their correlation in rat's upper digestive organs during growth and aging. Materials and Methods: Upper digestive organs(buccal mucosa, gingiva, palate, submandibular and parotid glands, and tongue) were aseptically removed from Sprague-Dawley rats of fetal(gestational 20 days), growing(1, 2, 3, 5, and 7 weeks after birth) and adult(12 week old). Samples for telomerase activity were frozen on liquid nitrogen immediately after sacrifice, and stored until the use at $-75^{\circ}C$ in order to measure it. Telomerase activity was measured by a PCR-based telomeric repeat amplication protoco(TRAP) assay and quantitated with Photometric Telo TAGGG Telomerase PCR ELISA plus(Roche Diagnostics GmbH. Mannheim. Germany). PCNA expression were measured immunohistochemistry with anti PCNA Ab-1, Clone PC10(NeoMark. California. USA). Results: 1. Telomerase activities in buccal mucosa, palate and gingiva were the highest in fetus and decreased gradually or rapidly after birth and then diminished, but In salivary gland and tongue were the highest in fetus and also high at 1 week and then decreased rapidly. 2. PCNA expression in buccal mucosa, gingiva, Tongue and salivary gland was the highest in fetus and decreased gradually and then diminished. but only in palate decreased rapidly after birth and then diminished. Conclusion: The highest telomerase activity of embryonic stage decreased rapidly after birth in rat's upper digestive organs. There may be a developmental regulation of telomerase activity, but not a tissue-specific. This telomerase activity seems correlated closely with PCNA expression in rat's upper digestive system.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1251-1254
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• 2016

Background: Oral squamous cell carcinoma (OSCC), the most common malignancy of the oral cavity, shows geographical variation with respect to the age, sex, site and habits of the population. The histolopathologic grade of the tumor is closely related to its tissue of origin. This study was conducted to establish the prevalence of OSCC in relation to patient sex, age, habits and sites of lesions. Materials and Methods: A total of 130 cases of histopathologically diagnosed OSCC were selected for the study, out of which 66, 38 and 26 were well (WD), moderately (MD)and poorly differentiated (PD), respectively. Sections were stained with haematoxylin and eosin and graded according to a modified Borders's system. Then statistically analyzed different grades of OSCC for correlations with other variables. Results: In our study the majority cases of OSCC were found in the 5th to 7th decades of life, males acconting for 53%. The most common site was the buccal mucosa and most cases had habit of tobacco use either in the form of chewing or smoking or both. When the different grades of OSCC were compared with different sites a statistically significant value was observed (P=0.029). Conclusions: The incidence of high grade PD is very much less in female patients but in males such lesions were common. In our location population the buccal mucosa is the most common site due to the tobbaco habits of the patients and majority cases of the buccal mucosa are WD whereas in tongue, floor of the mouth and palate PD are common.

• Journal of Periodontal and Implant Science
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• v.45 no.4
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• pp.128-135
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• 2015

Purpose: The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunctive collagen membrane (CM) for preserving the buccal bone when used in association with immediate implant placement in dogs. Methods: Immediate implant placements were performed in the mesial sockets of the third premolars of five dogs. At one site the TM was attached to the fixture with the aid of its own stabilizers and then covered by a CM (CM group), while the contralateral site received only TM (TM group). Biopsy specimens were retrieved for histologic and histomorphometric analyses after 16 weeks. Results: All samples exhibited pronounced buccal bone resorption, and a high rate of TM exposure was noted (in three and four cases of the five samples in each of the TM and CM groups, respectively). A dense fibrous tissue with little vascularity or cellularity had infiltrated through the pores of the TM irrespective of the presence of a CM. The distances between the fixture platform and the first bone-implant contact and the bone crest did not differ significantly between the TM and CM groups. Conclusions: Our study suggests that the additional use of a CM over TM does not offer added benefit for mucosal healing and buccal bone preservation.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.