• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.359-366
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• 2010

It was easy to find that children of a skeletal anterior crossbite in the early mixed dentition period showed a stark difference in the dental maturity between their maxillary and mandibular teeth, if they have stronger physical characteristics. If the difference of dental age between maxillary and mandibular teeth which can be identified via panoramic radiographs may serve as an early sign of class III malocclusion, this is considered valuable as a tool of early detection diagnosis. We obtained lateral cephalometric radiographs, panoramic radiographs, working model and clinical images of patients of Hellman dental age IIA and IIC who visited the department of pediatric dentistry, Pusan National University Dental Hospital and examined them to select 50 patents for normal occlusion group and skeletal anterior crossbite group, respectively. Their panoramic radiographs were used for the Demirjian's method to figure out dental ages of maxillary and mandibular teeth of each group and the eruption rate of the first molars. Their differences are as follows: 1. In both groups, the dental ages from Demirjian's method were advanced than the chronological ages. No sexual dimorphism was detected for the chronological or dental age in either group (p>0.05). 2. The difference of dental age of maxillary and mandibular teeth between the normal occlusion group and crossbite group was 0.22 and 0.69 years, respectively, with a higher difference in crossbite group(p<0.05). 3. Compared to the normal occlusion group, the crossbite group showed a higher difference in the eruption rate between maxillary and mandibular first molar(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.555-560
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• 1994

Among the permanent teeth. the first permanent molars play the greatest role in occlusion and function. So, the congenital missing, abnormal reuption or abnormal formation of the first permanent molars in the course of arch development would inflict normal development of dental arches. Therefore, early detection of abnormal cases related to first permanent molars and understanding of current and predictable clinical problems are essential for proper occlusal guidance in children. With the aim of investigating the clinical patterns of delayed eruption of first permanent molars in children, panoramic tomograms of the childern in mixed and early permanent dentition were observed and analyzed. The results were as follows: 1. Among the delayed eruption of first permanent molars, on tooth or bilateral teeths were affected most frequently. Delayed eruption was more prevalent in maxilla than in mandible. 2. The formation of tardily erupted teeth were also delayed. 3. Delayed eruption was generally limited in first molars or molar segments. 4. Delayed eruption of first permanent molars is accompanied by abnormal position of tooth germs, for example, ectopic eruption, delayed dental age, delayed localized tooth formation and generalized congenital missing. 5. There was a tendency of delayed formation or congenital missing of second molars distal to tardily erupted 1st molars. And that was more marked in maxilla than in mandible. 6. There was reported that affected 1st molars show various size and shapes. Maxillary 1st molars showing delayed eruption showed a tendency of having 3 cusps. But, tardily erupted mandibular 1st molars showed no significant reduction in mesiodistal dimension, as reported. 7. In some cases, the delayed eruption of 1st permanent molars was associated with ectopic eruption, but their formation was not usually retarded. 8. In skeletal class III cases, there showed a tendency of mandibular 1st molars to erupt earlier than maxillary 1st molars with greater interval than in normal occlusion.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.757-765
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• 2008

Maxillary central incisor impactions occur infrequently. Their origins include various local causes, such as odontoma, supernumerary teeth, space loss, and disturbances in the eruption path, also trauma and apical follicular cysts. Impacted teeth can cause serious dental and aesthetic difficulties as well as psychological problems especially in anterior regions. Although the impaction of maxillary incisor occurs less frequently than that of the maxillary canine, it is of concern to parents during the early mixed dentition stage because of the uneruption of the tooth. Forced eruption of impacted teeth should be considered in young patients because this technique can lead to suitable results from a periodontal, occlusal, and esthetic perspective at an earlier stage better than with other treatment options. This report presents the surgical and orthodontic treatment of cases with horizontally impacted and dilacerated maxillary central incisors. For each patient, we used the closed eruption method, placed an attachment on the impacted tooth on surgery, and fully closed the flap. Traction was applied immediately. The impacted tooth erupts through the healed tissue in a manner resembling normal eruption.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.4
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• pp.298-305
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• 2014

The purpose of this study is to evaluate the effects of facemask therapy in patients with Class III malocclusion with two types of bonded expanders covering different numbers of anchored teeth and to compare the anchorage value of two types of bonded expander. Eighteen subjects with Class III malocclusion in early mixed dentition were included in this study, and subjects were divided into two groups based on the number of teeth covered by bonded expander: group 1 (splinting four teeth on each side, 9 subjects) and group 2 (splinting three teeth on each side, 9 subjects). Lateral cephalograms were obtained and assessed before (T1) and after (T2) the treatment. The facemask therapy showed skeletal effects including anterior movement of maxilla and backward rotation of mandible in both groups, with no significant differences between groups. Mesial movement of maxillary molars which indicates anchorage loss of the bonded expander was found in both groups, but significantly larger mesial movement was found in group 2 than in group 1. In conclusion, the value of anchorage was different according to the number of teeth covered by bonded expander as an intraoral anchorage of facemask, but there were no significant differences in skeletal effects.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.1-12
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• 2006

The purpose of this study were to evaluate the efficacy of the newly developed Digital Imaging Fiber-Optic Trans-illumination (DIFOTI) system in detecting carious lesions in vivo as gold standard with confocal laser scanning microscopy and compared the efficacy of traditional radiography and DIFOTI system in vito as gold standard with confocal laser scanning microscopy, too. For the in vivo study, the subject pool consisted of 23 grammar school age patients just prior to entering the mixed dentition phase Each patient was given a DIFOTI examination of the anterior and posterior teeth. During $6{\sim}8$ months, the naturally expire primary teeth were collected and the efficacy of DIFOTI system was compared with confocal laser scanning microscopy. For in vitro study, 40 primary teeth were collected and decalcified by Carbopol decalcification solution for 1, 2, 4 and 8 days. Every experiment period, all teeth were DIFOTI examined and sectioned to take an image of confocal laser scanning microscopy Sensitivity and specificity were calculated from the result of DIFOTI examine and confocal laser scanning microscopy analysis. The results are as follows : 1. From the in vivo study, the sensitivity of DIFOTI examine was 0. 61 and specificity was 0.63. 2. From the in vivo study, the sensitivity of DIFOTI examine was 0.71 and specificity was 0.75.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.587-597
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• 2004

Over the past 20 years, great strides have been made in research regarding the mechanisms involved in the progression of carious lesions, but new equipment and research tools need to be developed to continue these advancements in caries research. Various methods have been applied to reduce the incidence of carious lesions, which have led to a significant decrease in the number of occlusal caries, but a concurrent increase in the proportion of proximal carious lesions. New diagnostic equipment has been developed to detect early stage carious lesions, and these have demonstrated excellent laboratory results and show promise in clinical applications. The research presented here examines the efficacy of the newly developed $DIFOTI^{TM}$ system in detecting proximal carious lesions compared to traditional intraoral exam and bitewing radiography, possible problems or deficiencies of using the system in clinic, possible improvements that can be made to the system, and the efficacy of detecting early, reversible carious lesions that can be remineralized by preventative fluoride applications. The subject pool consisted of 23 grammer school age patients just prior to entering the mixed dentition phase. Each patient was given a thorough oral examination, radiographic examination consisting of bitewing radiographs of the posterior teeth, and $DIFOTI^{TM}$ examination of the anterior and posterior teeth. Each examination was carried out two times by two examiners, and the data were statistically analyzed. The results are as follows: 1. The mean alpha value of reliability test of the visual oral examination was as follows; occlusal surface was 0.8470. mesial surface was 0.6430, distal surface was 0.5727. lingual surface was 0.2807 and distal surface was 0.2339. When the examination was limited to posterior teeth, the mean alpha value was as follows; occlusal surface was 0.8577, distal surface was 0.8211, lingual surface was 0.7728, buccal surface was 0.7152 and mesial surface was 0.6782. 2. The alpha value of reliability test of the radiographic analysis of carious lesions of the occlusal, mesial, and distal surfaces was 0.8500. 3. The alpha value of reliability test of the $DIFOTI^{TM}$ diagnostic analysis of carious lesions of the occlusal, buccal, lingual, mesial, and distal surfaces was determined to be 0.7917. 4. The $DIFOTI^{TM}$ diagnostic system was found to be the most accurate means of detecting occlusal, buccal, and lingual surface carious lesions (p<0.05), while mesial and distal proximal carious lesions were most accurately assessed using bitewing radiography (p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.315-321
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• 2007

Removable appliance has many utilities in pediatric dentistry in the fields of space maintainance or occlusal guidance. In contrast to maxilla, many problems have occurred with mandible in using removable appliance such as deteriorated retention, inconvenience and patient's unwillingness to wear. It is probably due to adapting several retentive clasps at buccal side of the tooth, where there is actually little or no undercut especially in young children having the erupting teeth Moreover, acrylic base plate of conventional removable appliance is located at lingual parts, which leads to the conflict with alveolar crest undercut and sublingual soft tissues. Moreover, young children frequently do not follow the dentist's direction to elevate tongue properly during the impression taking process. Throughout this study, the position of clasps and acrylic baseplate was changed opposite to the traditional Hawley acrylic appliance in order to make a buccal acrylic appliance with buccal base plate and lingual clasp into primary dentition and early mixed dentition. This study was performed for the purpose of evaluating the buccal acrylic appliance in regards of patient compliance, retention and efficiency compared with traditional lingual acrylic appliance along with its merits and demerits. Buccal and lingual acrylic appliance were applied to 5 cases respectively which required space maintaining and tooth movement, and drew a comparison in relevance to patients' compliance, combination with the tongue's function and clinical effectiveness. According to this study, in every case buccal appliance was proved superior to lingual appliance in terms of retention and patients' compliance. Moreover, buccal appliance has shown to be similar to lingual appliance with respect to clinical effectiveness. Throughout this study, it was thought that, if removable appliance is to be applied to mandible, several drawbacks related to conventional lingual appliance shall be resolved. Conclusively, the buccal acrylic appliance is thought to be a good alternative in designing a mandibular appliance in young children and recommended to clinical applications.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.140-149
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• 2007

Cleft lip and palate are congenital craniofacial malformation. Reconstruction of dental arch in patient with alveolo-palatal clefts is very important, because they have many problems in functions and esthetics. Malnutrition, poor oral hygiene, respiratory infections, speech malfunctions, maxillofacial deformity, and psychological problems may be occured without proper treatment during the long period of management of the cleft lip and palate. So the treatment should be managed with a multidisciplinary approach. Bone grafting is a consequential step in the dental rehabilitation of the cleft lip and palate patient A complete alveolar arch should be achieyed of the teeth to erupt in and to form a stable dentition. And the presence of the cleft complicate the orthodontic treatment. Therefore bone grafting in patients with cleft lip and palate is a widely adopted surgical procedure. Grafted bone stabilizes the alveolar process and allows the canine or incisor to move into the graft site. After the bone grafting, orthodontic closure of the maxillary arch has become a common practice for achieving dental reconstruction without any prosthodontic treatment. Various grafting materials have been used in alveolar clefts. Iliac bone is most widely fovoured, but tibia, rib, cranial bone, mandible have also been used. And according to its time of occurrence, the bone graft may be divided into primary, early secondary, secondary, late secondary. Bone grafting is called secondary when performed later, at the end of the mixed dentition. It is the most accepted procedure and has become part of treatment of protocol A secondary bone graft is performed preferably before the eruption of the permanent canine in order to provide adequate periodontal support for the eruption and preservation of the teeth adjacent to the cleft. In this report, we report here on a patient with unilateral cleft lip and palate, who underwent iliac bone graft. The cleft was fully obliterated by grafted bone in the region of the alveolar process. The presence of bone permitted physiologic tooth movement and the orthodontic movement of adjacent tooth into the former cleft area. Satisfactory arch alignment could be achieved in by subsequent orthodontic treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.117-123
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• 2010

Tooth eruption is the movement of the tooth from the developing place in the alveolar bone to the functional position in the oral cavity. The permanent incisors originate from the dental lamina on the lingual side of preceding deciduous tooth and erupt to the level of the occlusion through the well developed gubernacular cord. Ectopic eruption is a developmental disturbance in the eruption pattern of the permanent dentition. Most of the ectopically erupted lower incisor has been found in lingual side. The ectopically erupted tooth could be repositioned by orthodontic force in the early mixed dentition, which could help preventing the problems of loss of space and the lingual tilting of the lower anterior teeth. An eight-year-old girl visited the department of pediatric dentistry, Yonsei Dental University Hospital, for the evaluation and the treatment of the lower right lateral incisor, which was horizontally erupted in the lingual side, parallel to the mouth floor. Her tongue was placed on the labial side of that tooth. There was no previous dental history of dental caries or trauma on the pre-occupied primary incisor. Clinical and radiographic examinations including the computed tomography(CT), showed no evidence of dilacerations on root. Therefore, we decided to start active orthodontic traction of the lower right lateral incisor. We designed the fixed type of buccal arch wire and the lip bumper with hook for the traction. Button was attached to the lingual side of the ectopically positioned tooth. Elastic was used between the appliance and the button on that tooth. After the tooth become upright over the tongue level, appliance was change to the removable type and periodic check-up with occlusal guidance was followed to monitor the position of the tooth. In this case using the fixed appliance with modified form of lip bumper and hook embedded in acrylic part instead of extraction was very efficient up-righting the ectopically erupted tooth toward the occlusal plane.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.85-97
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• 1998

The purpose of this study was to observe the effects of sodium fluoride on the bony repair and regeneration processes after the rapid palatal expansion in the growing dogs. Eighteen dogs were divided into experimental and control groups. They were in the late mixed dentition. The rapid Palatal expansion was undertaken in all the animals($180^{\circ}$ turn/day) for ten days. The animals were sacrificed on 0, 15 and 45 days after the finish of expansion. One mg NaF/kg of body weight/day were given orally to the experimental group. Blood samples were drawn before and after expansion and the se겨m calcium, phosphate and alkaline phosphatase level were measured. The undecalcified bone section of midpalatal suture area was made, and observed under the light microscopy The results were as follows ; 1. The day after expansion, the infiltration of inflammatory cells were prominent and the new bone formation started at the edges of the two palatal plates bodering the midpalatal suture in both groups. Especially, the newly formed osteoid were very extensive and the osteoblasts lining the osteoid were very active in the experimental group. 2. At fifteen days after expansion, the active osteoblasts lining the osteold at the surface of trabecular bony spicules and active new bone formation were observed in the both groups. However, the cellular activity and new bone formation were more prominent In the experimental group. 3. At forty five days after expansion, the continuous osteoid and new bone formation and active osteoblasts were observed in the experimental group. But these phenomena were not observed in the control group. In the control group, the numerous osteoclasts were adjacent midpalatal suture and the bony remodeling process was begun. The serum alkaline phosphatase level was maintained highly in the experimental group, but decreased in the control. According to the above results, the author reached the conclusion that sodium fluoride has the stimulation effects on the osteoid production of the osteoblasts during the healing process after the rapid Palatal expansion more continuously.