• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.509-529
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• 1992

Skeletal Class III malocclusion is one of the most difficult type to treat and stabilize. For a child with developing skeletal Class III malocclusion, the treatment objective would be to stimulate maxillary growth, particulary one who has markedly deficient maxilla, and to restrain excessive mandibular growth. In order to stimulate the maxillary growth, maxillary protraction appliance is the one of the effective orthopedic appliances in skeletal Class III. The purposes of this study were as follows ; evaluation of the skeletal and dental changes of the maxillary protraction in children with Class III Maxillary deficiency , comparison of the clinical effects between the group with RPE and labiolingual intraoral appliances , comparison of the clinical effects and stability related to the ages of the patients : stability of the maxillary protraction about 1 year after retention. The subjects consisted of 60 children between the ages of 8 and 13.4 who were diagnosed as Class III with maxillary deficiency and were treated with Face Mask (Delaire Type) from the Dept. of Orthodontics Yong Dong Severance Hospital, Yonsei University. 48 children wore the RPE and 12 children wore Labiolingual Appliance. Lateral Cephalograms were taken for each patient at before and after correction of anterior cross-bite in 60 children, and after an observation period of 10 to 14 months in 19 children. X and Y coordinate of 10 landmarks were analyzed using a horizontal line through sella and rotated $6^{\circ}$ down anteriorly as the horizontal reference axis, and a perpendicular verticual line through sella as the vertical reference axis. Each of the 31 measurents (10 verticals, 10 horizontals, 2 angles and 9 others) was statistically analyzed using SPSS/PC statistics. The results are as follows; 1. After maxillary protraction the maxilla and maxillary teeth moved downward and forward, while the mandible and mandibular incisor rotated downward and backward. 2. Maxillary protraction with rapid palatal expansion appliance was more effective than with labiolingual appliance. 3. More downward movement of the posterior palatal plane obserbed with maxillary protraction doing the midpalatal suture opening than with protraction after finishing the palatal expansion 4. The clinical effects of protraction and changes of the retention periods were not statistically significant among the age groups. 5. During the retention period, maxilla and maxillary teeth, and mandible and mandibular teeth moved downward and forward, however the mandibular changes were larger than the maxillary changes.

• Korean Journal of Cleft Lip And Palate
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• v.2 no.1_2
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• pp.29-41
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• 1999

Cleft lip and palate is the most frequent congenital facial deformity of the orofacial area. Successful management of patients with cleft lip / palate requires a multidiciplinary approach from birth to adult stage. Coordinated treatment by the cleft palate team is an essential requirement to obtain optimum treatment results. One of the negative effect of the early surgical interventions of lip and palate is a significant incidence of maxillary growth restriction that produces secondary deformities of the jaws and malocclusion that includes congenital missing of lateral incisor, malformed teeth, rotation or ectopic position of upper anterior teeth, and it has been thought due to the resistance of palatal scar tissue. In Orthodontic treatment for cleft lip / palate patients, expansion of upper dental arch or palatal suture is often needed to correct posterior and/or anterior cross bite and align upper teeth. Various appliances such as hyrax, quad-helix, fan-type expansion screw and jointed-fan type expander can be used for palatal expansion. In the orthodontic treatment of the cleft lip / palate patient, we must consider patient age and severity of palatal constriction for proper appliance selection, and must pay special attention to maintain the treatment results.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.4
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• pp.389-393
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• 2017

Purpose: The aim of this study is to evaluate the flexural strength of flexible resins and the flexibility of different resin splint (RS) systems in comparison with resin wire splint (RWS) system. Materials and methods: Three different resin materials (G-aenial flo, GA, GC; Superbond, SB, Sun medical; G-fix, GF, GC) were tested flexural strength test in accordance with ISO-4049:2000. For the flexibility test of splint systems, a artificial model with resin teeth was used to evaluate three types of resin splint systems (GA, SB, and GF) and one resin wire splint system. The left central incisor was simulated 'injured teeth' with third degree mobility. Three consecutively repeated measurements of periotest value were taken in horizontal direction, before and after splinting to access tooth mobility. The splinting effect was calculated through the periotest value. Differences were evaluated through One-way Anova and Tukey HDS post-hoc tests for pair-wise comparison (${\alpha}=.05$). Results: Although GA group showed significant higher flexural strength than SB and GF groups, all of three different resin splint systems produced a significantly higher and rigid splinting effect compared with 016" resin-wire splint system (P < .05). Conclusion: Within the limits of an in vitro study, it can be stated that resin splint systems are too rigid and may not be acceptable to treat tooth avulsion.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.658-665
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• 2007

Oligodontia is defined as the congenital absence of six or more teeth in dentition, excluding the third molars. The prevalence of congenital missing teeth is about 1.6 to 9.6% of population and the prevalence of oligidontia is about 0.08 to 1.1%. The mandibular second premolar is the most frequently absent after the third molar, followed by the maxillary lateral incisor and upper second premolar. Females seem to be affected slightly more than males. Oligodontia may occur either in isolation, or as a part of a syndrome such as ectodermal dysplasia. Different causes are possible for oligodontia: physical obstruction or distruction of the dental lamina, space limitation, functional abnormalities of the dental epithelium, failure of induction of the underlying mesenchyme, chemotherapy, radiotherapy or genetic factor. Because oligodontia would result in esthetic and functional problems, such as facial asymmetry or occlusal disharmony, early diagnosis from clinical and radiographic examination was necessary. And appropriate treatment plan should be followed. This case report was about oral conditions and treatment of the oligodontia patients who have no specific systemic disease.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.379-389
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• 1998

The purpose of the present study was to evaluate the change of tooth mobility following orthodontic tooth movement. Six orthodontic patients which had been treated with edgewise appliance were used. Tooth mobility was measured with Periostest at the time of the removal of orthodontic appliance and 1, 2, 3, 4, 6, 8, 10, 12, 16, 20, 24 weeks after appliance removal. Following results were obtained: 1. Tooth mobility upon the removal of orthodontic appliance showed individual variation while incisor showed greater mobility than the other teeth. 2. Tooth mobility showed continued decrease pattern until 24 weeks after appliance removal. 3. While maxillary incisors showed continued decrease pattern during the study period, the other teeth showed steep decline pattern during the first 12 weeks and gentle slope during the second 12 weeks. 4. The tooth mobility of the maxillary second premolar showed the most typical change in terms of the consistency of the decline. 5. There were no significant differences of tooth mobility between heavy- and light-contacted anterior teeth during experimental period. The results of the present study suggested that periodontal reorganization is not completed even in 24 weeks following orthodontic tooth movement.

• The Journal of the Korean dental association
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• v.56 no.5
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• pp.263-276
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• 2018

Long-term survival and prognosis of narrow-diameter implants have been reported to be adequate to consider them a safe method for treating a deficient alveolar ridge. The objective of this study was to perform case report of narrow-diameter implants with a trapezoid-shape in anterior teeth alveolar bone. A 50-year-old male patient presented with discomfort due to mobility of all of the maxillary teeth and mandibular incisors. Due to destruction of alveolar bone, four anterior mandibular teeth were extracted. Soft tissue healing was allowed for approximately 3 months after the extraction, and a new design of implant placement was planned for the mandibular incisor area, followed by clinical and radiological evaluation. Implant placement was determined using an R2GATE surgical stent. The stability of the implants was assessed by ISQ measurements at the first and second implant surgery and after prosthetic placement. At 1 and 3 months and 1 year after implantation of the prosthesis, clinical and radiological examinations were performed. Another 50-year-old male patient presented with discomfort due to mobility of the mandibular central incisors. For the same reason as in the first patient, implant placement was carried out in the same way after extraction. ISQ measurements and clinical and radiological examinations were performed as in the previous case. In these two clinical cases, 12 months of follow-up revealed that the implant remained stable without inflammation or additional bone loss, and there was no discomfort to the patient. In conclusion, computer-guided implant surgery was used to place an implant in an optimal position considering the upper prosthesis. A new design of a narrow-diameter implant with a trapezoid-shape into anterior mandibular alveolar bone is a less invasive treatment method and is based on the contour of the deficient alveolar ridge. Through all of these procedures, we were able to reduce the number of traumas during surgery, reduce the operation time and total treatment period, and provide patients with more comfortable treatment.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.315-320
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• 2017

PURPOSE. The aim of this investigation was to analyze the dimensions of clinical crowns and to classify the crown and the gingival type in the anterior teeth in Korean young adults. MATERIALS AND METHODS. Casts were obtained from 50 subjects ranging in age from 24 to 32. Measurements of length and width were made on the casts using a pair of digital calipers on the entire dentition. Crown thickness and papilla height were also measured and MDW/CL (mesiodistal width to clinical length) and CW/CL (cervical width to clinical length) ratios of the maxillary anterior teeth were calculated. The K-clustering method was used for CW/CL to classify the anterior tooth shape into three groups (tapered, ovoid, and square), and one-way analysis of variance and Duncan's post-hoc comparison were used to evaluate statistical significance between the groups. Pearson's correlation analysis was performed between tooth shape and papillary height (PH) to demonstrate the correlation between tooth shape and gingival morphological characteristics. RESULTS. The average length of the maxillary central incisors was 9.89 mm; the mesio-distal width was 8.54 mm; and the ratio of width/length was 0.86 in Korean young adults. The average bucco-palatal thickness of the central incisor was 3.14 mm at the incisal 1/3 aspect. Ovoid type was the most common tooth shape (48%), followed by square type (29%) and taper type (23%) in the central incisors of Korean young adults. Tooth shape and gingival type were correlated with each other. CONCLUSION. New reference data were established for tooth size in Korean young adults and the data show several patterns of tooth shape and gingival type. Clinicians should diagnose and treat based on these characteristics for better results in the Korean population.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.687-698
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• 2000

The purpose of this study was to evaluate the changes of skeletodental patterns during Class II treatment and its retention period. Forty two patients of Class II malocclusion, which was treated with nonextraction or first premolar-extraction were selected and their lateral cephalograms were examined in this study. Various skeletodental changes in lateral cephalograms of pre-treatment, post-treatment and retention were measured by superimposition in reference to the cranial base for jaws, the palatal plane for maxillary teeth, and mandibular plane for mandibular teeth. The data were analyzed by paired t-test. In this study, occlusal plane showed the significant anterior downward steepening after active treatment, and remained during retention period. In the nonextraction group, maxillary incisors were retracted and extruded during treatment. Maxillary molars were extended, and mandibular molar were uprighted, with no mesial movement. In the extraction group, both maxillary and mandibular incisors were retracted and extruded. Maxillary molars were extruded and moved mesially, and mandibular molars were extruded and moved mesially with no mesial tilting. During retention period in both groups, there were tendencies of labial tipping of maxillary incisor, and mesial tipping of maxillary and mandibular molar. But the changes were not significant and most of teeth showed no change in vortical and horizontal direction.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.4
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• pp.674-696
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• 1997

There're many cases that should be reconstructed with post and core when clinical crown is destructed. But this post and core restoration may cause damaging stress on the teeth. Previous finite element study was restricted to normal bone model relatively close to cemen-toenamel junction. Moreover, the test of a model with diminished bone support was rare. The purpose of this study is to test the effects of alveolar bone loss on the magnitude, stress distribution and displacement of post reconstructed teeth. In this study, it was assumed that the coronal portion of upper incisor was severely destructed. After conventional endodontic treatment, it was restored with post and core. The PFM restoration was made on it. This crown was cemented with ZPC. Alveolar bone was classified by 4 types of bone, such as normal, 2 mm, 4 mm, 6 mm bone, according to the bone loss. Meanwhile, the material of post are divided into 2 types of materials, such as gold, co-cr. Force was applied to two directions. One was fuctional maximum bite force (300 N) applied to the spot just lingual to the incisal edge with the angle of 45 degree to the long axis of the tooth, and the other one was horizontal force (300 N) applied to the labial surface. The results analyzed with three dimensional finite element method were as follows : 1. Stress was concentrated on the adjacent dentin of the post apex, one third portion of the post apex and the labial & lingual mid-portion of the root in all case. The stress of middle third of the root was apparently concentrated on the labial aspect. 2. The stress on adjacent dentin of the post apex and one third of the post apex increased as alveolar bone height moved apically. This increase was dramatic beyond 4 mm bone loss model. 3. The stress of the post apex was spreaded to the middle third of the post and greater than gold post in the case of metal post. 4. The displacement of the neck of post was the greatest in one of the post-cement interface and this increased as alveolar bone height moved apically. Besides the displacement of the metal post is slightly lower than one of the gold post.

• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.198-205
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• 1991

We obtained successful functional and esthetic results by grafting of iliac marrow-cancellous bone in 2 cases of alveolar-palatal cleft patients. Bone graft of alveolar-palatal clefts provide bony support to adjacent teeth of cleft area, prevented from relapse of orthodontic arch expansion, closure of oroantral fistula and improvement of speech problem. 1. In one case, extraction of upper right central incisor that was little bone support, alignment of rotated teeth and expansion of collapsed arch segment were done with pre-ortodontic treatment. The other case, Bone grafting was done after removal of prosthesis with no preorthodontic treatment. 2. After mucoperiosteal incision in cleft area. The mucosal flap of labial area, palate and nose were separation and the raised nasal mucosa was sutured for closure of oroantral fistula. Then, the iliac marrow-cancellous bones were grafted to cleft site. 3. After 6 months of operation, we had seen the new bone deposition to cleft site in dental radiography and prosthetic treatments of missing teeth were done.