• Journal of dental hygiene science
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• v.24 no.3
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• pp.125-133
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• 2024

Background: The management of dental plaque and the appropriate use of oral hygiene tools are crucial for oral health. With increasing interest in oral health care, various oral hygiene products are available on the market. As the most basic oral hygiene tool, the large-head toothbrush has gained significant consumer interest. This study evaluates the suitability of large-head toothbrushes as oral hygiene tools by comparing their efficacy with that of regular-sized toothbrushes. Methods: We evaluated the efficacy of large-head and regular-sized toothbrushes. The amount of dental plaque before and after brushing was measured using quantitative light-induced fluorescence digital (QLF-D) images and the plaque index (PI) in adult participants with more than 28 teeth (n=15/group). After brushing, the collected toothbrushes were rinsed 10 times in clean water, thoroughly dried, and weighed on an electronic scale. Data were analyzed using the Wilcoxon signed-rank test with SPSS Statistics Version 29.0. Results: QLF-D analysis showed a significant decrease in fluorescence intensity scores after use of a regular-sized toothbrush, whereas the scores after use of a large-head toothbrush were not significantly reduced. PI measurements indicated significant reductions in dental plaque for both head types. However, detailed analysis by tooth surface revealed that the regular-sized toothbrush significantly reduced plaque on the proximal, palatal/lingual, and labial/buccal surfaces. In contrast, the large-head toothbrush only showed significant reductions in place on the proximal and palatal/lingual surfaces, not on the labial/buccal surface. Additionally, compared to the regular-sized toothbrush, the large-head toothbrush retained more toothpaste residue despite similar cleaning efforts after brushing. Conclusion: Compared to the regular-sized toothbrush, the large-head toothbrush showed lower overall efficacy in dental plaque removal. The results of this study provide significant information regarding the use of large-head toothbrushes.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.151-158
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• 2010

The purpose of this study was to investigate the tooth surface caries patterns in the primary dentition according to breast or bottle feeding. The subjects of study were 815 children, 36 to 71 months old, in Iksan, Cheongju and Ulsan cities. The caregivers of the children were asked which they fed between the breast milk and the infant formula during the 1st year after birth and the duration of feeding. There was no significant difference in dmfs between the breast milk group and the infant formula group(significance level 0.05, same below). Tooth groups, tooth surface groups, teeth, and tooth surfaces which had significantly higher dmfs in the breast milk group than in the infant formula group were upper anterior teeth(tooth groups), upper incisors' buccal and proximal surfaces(tooth surface groups), upper incisors and upper second molars(teeth), upper central incisors' buccal and distal surfaces, upper lateral incisors' buccolingual and proximal surfaces, upper 2nd molars'lingual, proximal, and occlusal surfaces, and lower 2nd molars' buccal and distal surfaces. In the breast milk group, tooth groups, tooth surface groups, teeth, and tooth surfaces which dmfs significantly increased as the duration of the feeding increased were upper anterior teeth and upper molars(tooth groups), upper anterior teeth's proximal surfaces, upper molars' buccolingual, proximal, and occlusal surfaces, lower molars' proximal surfaces(tooth surface groups), upper anterior teeth, upper molars, lower 2nd molars(teeth), upper anterior teeth's proximal surfaces, upper 1st molars'buccolingual, proximal, and occlusal surfaces, upper 2nd molars' buccal surfaces, and lower 2nd molars'mesial surfaces(tooth surfaces). In the infant formula group, dmfs increased after 3 years of feeding, but the difference was not significant. Caries prevention is necessary in case of breastfeeding more than two years.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.373-384
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• 2001

Cellular proliferation is an intricately regulated process mediated by the coordinated interactions of critical growth control genes. Two of these factors in mammalian cells are the p53 and mdm-2 genes. A protein product of the mem-2 oncogene has been recently shown to associate with the protein encoded by the tumor suppressor gene p53. The p53 tumor suppressor protein is stabilized in response to DNA damage and other stress signals and causes the cell to undergo growth arrest or apoptosis, thus preventing the establishment of mutations in future cellular generations. Mutation or loss of p53 is a very common event in tumor progression. It occurs in about 50% of all tumors analysed including of colon, lung, breast and liver. The cellular mdm-2 gene, which has potential transforming activity that can be activated by overexpression, is amplified in a significant percentage of human sarcoma and in other mammalian tumors. Proteins encoded by the mdm-2 gene are able to bind to the p53 protein and, when overexpressed, can inhibit p53's transcriptional activation function, thus mdm-2 can act as a negative regulator of p53 function. Experimental study was performed to observe the relationship between p53 gene mutation and mdm-2 protein expression and apply the results to the clinical activity. 36 golden syrian hamster each weighing $60{\sim}80g$ were used and painted with 0.5% DMBA by 3 times weekly on the right buccal cheek(experimental side) for 6, 8, 10, 12, 14 and 16 weeks. Left buccal cheek(control side) was treated with mineral oil as the same manner to the right side. The hamsters were sacrificed on the 6, 8, 10, 12, 14 & 16 weeks. Normal and tumor tissues from paraffin block were examined for histology and immunohistochemistry observation, and were completely dissected by microdissection and DNA from both tissue were isolated by proteins K/phenol/chloroform extraction. Segments of the hamster p53 exons 5, 6, 7 and 8 were amplified by PCR using the oligonucleotide primers, and then confirmational change was observed by SSCP respectively. The results were as follows : 1. Dysplasia at 6 weeks, carcinoma in situ at 8 weeks and invasive carcinoma from 10 weeks could be observed in experimental groups. 2. p53 mutations were detected in 10 of the 36(28%) and the exons 6(6 of the 10 : 60%) was the most hot spot area among the highy conserved region(exons 5, 6, 7 & 8). 3. Immunohistochemical study confirmed 22 of the 36(61%) of p53 expression involving 10 of p53 mutations. 4. mdm-2 expression of was showed in 3 of the 36(8%) involving 1 of the 22 of p53 expression and 2 of the 14 of p53 non-expression. From the above results, mutation of p53 gene or expression of p53 protein may have the influence of the DMBA induced carcinoma of hamster buccal pouch but the expression of mdm-2 protein may not have relationship with tumorigenesis.

• The korean journal of orthodontics
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• v.32 no.5 s.94
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• pp.343-353
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• 2002

This study was designed to investigate the stress distribution of alveolar bone in case of on masse retraction with lingual K-loop archwire using the 3-dimensional photoelastic stress analysis followed by stress freezing process. Lingual K-loop archwire which had loop in 15mm height was used and activated by retraction force of 350gm per each side. The results were as follows 1. Central incisor : As the closer side to crown, the larger tensile stress was distributed at both mesial and labial surfaces and the larger compressive stress was distributed at distal surface. As the closer side to root apex, the larger compressive stress was distributed at lingual surface. The compressive stress was distributed at root apex. 2. Lateral incisor : The tensile stress was distributed at the coronal side of mesial surface. The compressive stress was distributed at distal surface. As the closer side to crown, the larger tensile stress was distributed at labial surface. The tensile stress was distributed at coronal side and the compressive stress was distributed at apical side of lingual surface. The compressive stress was distributed at root apex. 3. Canine The tensile stress was distributed at coronal side and the compressive stress was distributed at apical side of mesial surface. The tensile stress was distributed at distal surface. As the closer side to crown, the larger tensile stress was distributed at both mesial and distal surfaces. The compressive stress was distributed at root apex. 4. Second premolar : The tensile stress was distributed at mesial surface. The compressive stress was distributed at coronal side and the tensile stress was distributed at apical side of distal surface. The compressive stress was distributed at coronal side of buccal surface. As the closer side to crown, the larger tensile stress was distributed at lingual surface. The compressive stress was distributed at root apex. 5. First molar . As the closer side to crown, the larger tensile stress was distributed at both mesial and distal surfaces. No stress was distributed at buccal surface and palatal root apex. As the closer side to crown, the larger tensile stress was distributed at both lingual surfaces. The compressive stress was distributed a4 buccal root apexes. 6. Second molar The compressive stress was distributed at all root apexes. As the closer side to crown, the larger compressive stress was distributed at both mesial and lingual surfaces, and the larger tensile stress at both distal and buccal surfaces. Transverse bowing effect was observed in on-masse retraction with lingual K-loop archwire, however vertical towing effect was not. Rather, reverse vortical bowing effect was developed.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.25-38
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• 2001

The purpose of this study was to compare the force, the displacement and the stress distribution on the maxillary first molars altered by the application of various asymmetric head-gear. For this study, the finite element models of unilateral Cl II maxillary dental arch was made. Also, the finite element models of asymmetric face-bow was made. Three types of asymmetric face-bow were made : each of the right side 15mm, 25mm and 35mm shorter than the left side. We compared the forces, the displacement and the distribution of stress that were generated by application of various asymmetric head-gear, The results were as follows. 1. The total forces that both maxillary first molars received were similar in all groups. But the forces that mesially positioned tooth received were increased as the length of the outer-bow shortened, and the forces that normally positioned tooth received were decreased as the length of the outer-bow shortened. 2. In lateral force comparison, the buccal forces that normally positioned tooth received were increased as the length of the outer-bow shortened, and the buccal fortes that mesially positioned tooth received were decreased as the length of the outer-bow shortened. Though the net lateral force moved to the buccal side of normally positioned tooth as the length of the outer-bow shortened, both maxillary first molars received the buccal force. That showed 'Avchiai Expansion Effect' 3. The distal forces, the extrusion forces and the magnitudes of the crown distal tipping that mesially positioned tooth received were increased as the length of the outer-bow shortened, and the forces that normally positioned tooth received were decreased as the length of the outer-bow was shortened. 4. The magnitude of the distal-in rotation that normally positioned tooth received were increased as the length of the outer-bow was shortened. But, mesially positioned tooth show two different results. For the outer-bow 15mm shortened, mesially positioned tooth showed the distal-in rotation, hut for the outer-bow 25mm and 35mn shortened, mesially positioned tooth showed the distal-out rotation. Thus, the turning point exists between 15mm and 25mm. 5. This study of the initial stress distribution of the periodontal ligament at slightly inferior of the furcation area revealed that the compressive stress in the distobuccal root of the normally positioned tooth moved from the palatal side to the distal side and the buccal side successively as the length of the outer-bow shortened. 6. This study of the initial stress distribution of the periodontal ligament at slightly inferior of the furcation area revealed that the magnitudes of stress were altered but the total stress distributions were not altered in the mesiobuccal root and the palatal root of normally positioned tooth, and also three roots of mesially positioned tooth as the length of the outer-bow shortened.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.406-415
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• 2009

Purpose: The purpose of this study was to compare the marginal fitness and fracture load of the zirconia copings according to the design with different thickness and coloration. Material and methods: The evaluation was based on 80 zirconia copings. Zirconia copings were fabricated in design with different thicknesses using CAD/CAM system (Everset, KAVO dental GmbH, Biberach, Germany). The designs of copings were divided into four groups. The first group consisted of copings with uniform thickness of 0.3 mm. The thickness in the second group was 0.3 mm on the buccal surface and 0.6 mm on the lingual surface. The third group consisted of coping with uniform thickness of 0.6 mm. The thickness in the fourth group was 0.6 mm on the buccal surface and 1mm on the lingual surface. Each group consisted of 10 colored and 10 uncolored copings. Half of the copings (40) processed with a milling system according to the specific design were sent to be given a color (A3) through saturation in special dye by a manufacturing company. Just after sintering, the marginal discrepancies of copings were measured on the buccal, lingual, mesial and distal surfaces of metal die, under a Video Microscope System (sv-35, Sometech, Seoul, Korea) at a magnification of $\times$ 100. It was remeasured after the adjusting of the inner surface. Next, all copings were luted to the metal dies using reinforced cement {GC FujiCEM (GC Corp. Tokyo, Japan)} and mounted on the testing jig in a Universal Testing Machine (Instron 4467, Norwood, MA, USA). The results were analyzed statistically using the one-way ANOVA test. Results: The obtained results were as follow: 1. The measured value of marginal discrepancy right after sintering was the greatest in the contraction of the buccal area in all groups, except for group I2. 2. There was no significant difference of marginal fitness among the groups in the colored zirconia group (P<.05). 3. When the marginal fitness among the groups in the uncolored zirconia group was considered, group II2 had the smallest marginal discrepancy. 4. When the colored and uncolored groups with the same design were compared, there was a significant difference between I1 and II1 groups. In group 2, 3, and 4, the uncolored zirconia had the greatest marginal fitness (P<.05). 5. After adjustment of inner surface, there was no significant difference in the marginal fitness in all groups when color and design of the zirconia coping were compared. 6. The fracture load of CAD/CAM zirconia copings showed significant difference in group 1, 2, 3, and 4. I4 and II4 had the strongest fracture load. 7. When groups with different color and same design were compared, all colored groups showed greater fracture load (P>.05), with no significance. Conclusion: There was difference in the marginal fitness according to the design and coloration of zirconia copings right after sintering, but it was decided that the copings may well be used clinically if the inner surface are adjusted. The copings should be thick enough for the reinforcement of fracture strength. But considering the esthetics of the visible surfaces (labial and buccal surface), the thickness of copings may be a little thin, without giving any significant effect on the fracture strength. This type of design may be considered when giving priority to preservation of tooth or esthetics.

• Animal cells and systems
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• v.1 no.2
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• pp.271-279
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• 1997

As a result of examining the specimens collected from various freshwater bodies since 1995, four eutardigrades are added to Korean fauna: lsohypsibius brevitubulatus n. sp., I. baldii (Ramazzotti), I. marcellinoi (Binda and Pilato), and Diphascon (Diphascon) higginsi Binda. I. brevitubulatus n. sp. differs from its congeners by having a combination of the following characteristics: smooth cuticle, rather big body size, short and broad buccal tube, presence of lunules, and pharynx bearing 3 rod-like macroplacoids without microplacoid. All the species are illustrated and briefly commented on their habitats with the associated fauna.

• Imaging Science in Dentistry
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• v.31 no.4
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• pp.241-245
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• 2001

A 16-year-old female was admitted to Wonkwang dental hospital with a chief complaint of painful ulceration on right buccal mucosa around mandibular 3rd molar area. Computed tomography and magnetic resonance imaging showed relative large soft tissue mass on the infratemporal fossa and masseter muscle region. By the feature of T1-weighted and T2-weighted of MR imaging, we suspected this mass as a kind of myogenic sarcoma. Histopathological and immunohistochemical studies established a definitive diagnosis of embryonal rhabdomyosarcoma. A review of the literature was also presented.

• The Journal of the Korean dental association
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• v.15 no.1
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• pp.27-31
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• 1977

Dentigerous cysts are closed epithelium-lined sacs formed about the crowns of unerupted teeth. Most of them probably are the result of degenerative changes in the reduced enamel epithelium. The authors observed 1 3 year old girl with a swelling and buccal bony expansion of the left mandible. Roentgen examination showed a cystic area in the left side of mandible. Under general anesthesia by means of nasotracheal intubation, intraorally, the operation by enucleation consisted in surgical removal of dentigerous cyst and the left unerupted Ist molar of mandible. The cavity was partially sutured and packed with iodoform gauze. Healing was uneventful.

• The Journal of the Korean dental association
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• v.17 no.12 s.127
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• pp.923-926
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• 1979

In patient of long standing malunited maxillary fracture, maxillary osteotomy or refracture seems to be justifiable. This is a case of the patient, a 60 year old Korean female patient, presented a long-standing malunited maxillary fracture with dish-type face and functional disturbance in mouth opening. We performed upon her Le Fort I osteotomy only via labial-buccal horizontal incisions in one-stag operation. The result was good in esthetics and function.