• Journal of Korean Dental Science
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• v.15 no.1
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• pp.92-99
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• 2022

This case report describes the immediate loading of narrow diameter implants in the mandibular incisor area using full-digital flow. The 3-dimensional position of the implants was planned using digital software, and the corresponding surgical template was fabricated. The implants were inserted immediately after extraction and on the same day, the interim abutment and bridge were placed. At 8 weeks after surgery, the stability of the implants was measured and a digital impression was made using a scan body. Customized titanium abutments and a cement-type full zirconia bridge were delivered. At 36 weeks' follow-up, no clinical or radiographic complications were detected, and the patient was satisfied with the results.

• The Journal of the Korean dental association
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• v.19 no.1 s.140
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• pp.53-60
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• 1981

• The korean journal of orthodontics
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• v.52 no.3
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• pp.210-219
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• 2022

Objective: The purpose of this study was to examine the effectiveness and mechanism of clear aligner therapy for the correction of anterior open bite in adult nonextraction cases. Methods: Sixty-nine adult patients with anterior open bite were enrolled and classified into Angle's Class I, II, and III groups. Fifty patients presented with skeletal open bite (mandibular plane angle [MPA] ≥ 38°), whereas 19 presented with dental open bite. Fifteen cephalometric landmarks were identified before (T1) and after (T2) treatment. The magnitudes of planned and actual movements of the incisors and molars were calculated. Results: Positive overbite was achieved in 94% patients, with a mean final overbite of 1.1 ± 0.8 mm. The mean change in overbite was 3.3 ± 1.4 mm. With clear aligners alone, 0.36 ± 0.58 mm of maxillary molar intrusion was achieved. Compared with the Class I group, the Class II group showed greater maxillary molar intrusion and MPA reduction. The Class III group showed greater mandibular incisor extrusion with no significant vertical skeletal changes. Conclusions: Clear aligners can be effective in controlling the vertical dimension and correcting mild to moderate anterior open bite in adult nonextraction cases. The treatment mechanism for Class III patients significantly differed from that for Class I and Class II patients. Maxillary incisor extrusion in patients with dental open bite and MPA reduction with mandibular incisor extrusion in patients with skeletal open bite are the most significant contributing factors for open bite closure.

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.312-319
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• 2005

Streptococcus mutans and Streptococcus sobrinus are major etiological agents in enamel demineralization around orthodontic appliances. This study was designed to examine the prevalence of these streptococci on orthodontic brackets in vivo using polymerase chain reaction. Four incisor brackets in the upper and lower arches were removed and collected from 80 patients at the time of debonding. The genomic DMA of adhered bacteria was extracted and each dextranase gene of S. mutans and S. sobrinus was amplified using the specific oligonucleotide primers. The results showed that the maxillary incisor brackets were colonized by both cariogenic streptococci to a somewhat higher degree than that taken from the mandible. The prevalence of S. mutans was $50.0\%$ on the maxillary incisor brackets and $33.8\%$ on the mandibular incisor brackets, and that of S. sobrinus was $17.5\%$ and $15.0\%$, respectively. Both species were detected on the maxillary incisor brackets of 7 patients $(8.8\%)$ and the mandibular incisor brackets of 5 patients $(6.3\%)$. These results suggest that cariogenic streptococci can adhere to the incisor brackets and may be resident species on the incisor brackets.

• The Journal of the Korean dental association
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• v.48 no.11
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• pp.819-828
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• 2010

Activator is a removable functional appliance used for correcting the skeletal Class II malocclusion in children with the mandibular deficiency. Berlin standard activator modified from Andresen activator has following characters; do not cover the palatal surface for tongue space, relief on lingual surface of mandibular incisors and resin capping 1/3-1/2 of crown height on mandibular incisors for preventing labioversion of mandibular incisors, L-hook between maxillary lateral incisor and canine for anterior high pull headgear, relief on mandibular posterior bite block for differential eruption of posterior teeth. Two cases presented here had a mandibular deficiency and slight maxillary protrusion. First case (an 11-year-old girl) treated with Berlin standard activator and anterior high pull headgear for 13 months followed by fixed orthodontic appliance for another 29 months. Second case (a 12-year-old boy) treated with Berlin standard activator for 6 months followed by fixed appliance for another 24 months. Treatment results showed a significant improvement in sagittal skeletal and occlusal relationship without premolar extraction. Mandibular condyles were concentric in TMJ [ossa, and masticatory muscle activities were normalized after treatment. In the retention period facial harmony and occlusal stability was maintained.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.43-52
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• 2014

Purpose: This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. Materials and Methods: The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. Results: The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. Conclusion: These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.4
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• pp.246-251
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• 2012

Purpose: The purpose of the study is to evaluate the effectiveness of anterior segmental osteotomy (ASO) in bimaxillary protrusion (BP) patients by comparison between the mandibular soft and hard tissue changes from orthodontic treatment and ASO. Methods: All 44 patients were diagnosed with BP in Kyung-Hee Medical Center. Orthodontic treatment with teeth extractions were underwent by 23 patients (Group A) and 21 patients underwent ASO (Group B). Mandibular soft and hard tissue changes were measured and evaluated, which were based on the vertical and horizontal reference line in lateral cephalometric radiographs. Statistical significance between the changes and correlation between each measurement were analyzed. Results: The amount of B point movement was lesser than that of the lower incisal tip (LIT) retraction, and LIT was tilted lingually in group A. The posterior movement discrepancy between LIT and B point was insignificant, and the inclination of lower incisor was not changed in group B. The soft tissues, including the lower lip, showed a posterior movement and reduction in the depth of mento-labial groove. According to the correlation analysis, the movement of the lower incisor was significantly related to the movement of the lower lip in group A, and the movement of the lower incisor was significantly related to that of the movement of lower lip, B point and Pog in group B. Conclusion: The orthodontic treatment in BP patients results in posterior tilting movement of the lower incisor, but ASO results in the bodily movement of the lower incisor. Consequently, ASO is more effective in BP cases because it ensures the controlled movement of the lower incisors.

• The korean journal of orthodontics
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• v.21 no.2 s.34
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• pp.341-351
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• 1991

Dental maturity is one of the index of physiological maturity indicators. To investigate the relationship between dental maturity and chronological age, the author took the orthopantomograms of 984 students, aged 7 through 17 years, having normal occlusion. The orthopantomograms were examined and calcification degree of each tooth on the left side was rated according to the method described by Demirjian. On the basis of findings of this study, the following results were obtained. 1. The root completion periods of mandibular permanent teeth were as follows; Central Incisor M $8.32{\pm}1.03\;years$ F $7.96{\pm}1.04\;years$ Lateral Incisor M $9.40{\pm}1.30\;years$ F $9.01{\pm}0.90\;years$ Canine M $12.81{\pm}1.24\;years$ F $11.42{\pm}0.94\;years$ 1st Premolar M $12.76{\pm}1.74\;years$ F $12.19{\pm}1.33\;years$ 2nd Premolar M $13.31{\pm}1.88\;years$ F $12.88{\pm}1.49\;years$ 1st Molar M $9.60{\pm}1.69\;years$ F $9.30{\pm}1.16\;years$ 2nd Molar M $14.38{\pm}1.73\;years$ F $13.96{\pm}1.63\;years$ 2. Sexual differences in same age group at given calcification stage were not significant statistically. 3. The developmental order in mandibular permanent teeth was as follows; a) central incisor, b) lateral incisor, c) 1st molar, d) canine and 1st premolar, e) 2nd premolar, f) 2nd molar.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.11-22
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• 2018

Objective: The aim of this study was to determine cephalometric factors that help predict favorable soft-tissue profile outcomes following treatment with the Class II Twin-block appliance. Methods: Pre- and post-treatment lateral cephalograms of 45 patients treated with the Class II Twin-block appliance were retrospectively analyzed. Profile silhouettes were drawn from the cephalograms and evaluated by three orthodontists in order to determine the extent of improvement. Samples were divided into a favorable group (upper 30% of visual analogue scale [VAS] scores, n = 14) and an unfavorable group (lower 30% of VAS scores, n = 14). Skeletal and soft-tissue measurements were performed on the cephalograms and an intergroup comparison was conducted. Results: An independent t-test revealed that the following pre-treatment values were lower in the favorable group compared to the unfavorable group: lower incisor to mandibular plane angle, lower incisor to pogonion distance, point A-nasion-point B angle, sella-nasion line (SN) to maxillary plane angle, SN to mandibular plane angle, gonial angle, and symphysis inclination. The favorable group had a larger incisor inclination to occlusal plane. Moreover, the favorable group showed larger post-treatment changes in gonial angle, B point projection, and pogonion projection than did the unfavorable group. Conclusions: Class II malocclusion patients with a low divergent skeletal pattern and reduced lower incisor protrusions are likely to show more improvement in soft-tissue profile outcomes following Class II Twin-block treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.502-509
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• 2003

After 800 students of Chonbuk National University was examined, 86 people (male : 43, female : 43, mean age : 22.2 years old) was selected as a group of normal occlusion. From their gypsum cast, this conclusion was obtained. 1. Intra-observer measurement errors in buccolingual diameter, maxillary lateral incisors have somewhat bigger errors. In mesiodistal diameter, maxillary first molars and maxillary second molar have bigger numerical value. Mean errors of measurement are 0.051mm at buccolingual diameter of crown and 0.083mm at mesiodistal diameter. 2. Fluctuating asymmetry is 0.030 average in buccolingual diameter, and 0.037 average in mesiodistal diameter. Statistically there are no big differences. 3. Male has longer buccolingual diameter than female in every permanent teeth. Teeth which have statistical difference in buccolingual diameter are maxillary lateral incisor, maxillary canine, maxillary second molar, mandibular central incisor, mandibular canine, mandibular second premolar, and mandibular first molar. In mesiodistal diameter maxillary central incisor, maxillary canine, and mandibular first molar have statistically difference. 4. Tooth which has the biggest difference depending on gender is maxillary lateral incisor in buccolingual diameter and mandibular canine in mesiodistal diameter. 5. Both sexes have similar crown index. Male has bigger value of crown module measurement and crown area measurement in every tooth. Crown area considered as size of tooth from occlusal surface was bigger in male than in female statistically except some teeth, maxillary first premolar, mandibular lateral incisor, first premolar and second premolar.