• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.531-536
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• 2005

Infraclusion may be defined as teeth that stop their relative occlusal movement in the dental arches during or after the period of active eruption and then remain under the occlusal plane. Delayed exfoliation, malocclusion, increased susceptibility to dental caries and periodontal disease of both the neighboring teeth and retained molar, and dislocation of the successor are the consequencces of infraclusion of primary molars. Therefore, early diagnosis and appropriate treatments are necessary. The therapeutic approach of the infracluded teeth varied from preservation to extraction. The teeth with simple infraclusion without any signs of interference with occlusal and jaw development may be examined periodically with follow-up check and radiographically. However, if the infracluded tooth interferes with normal eruption of successor or shows any sign of delayed resorption, or the tipping of adjacent teeth or supraeruption of opposing teeth is expected, the teeth inflicted should be extracted and appropriate measures should be provided in order to maintain the normal development of occlusion and dentition. The adjacent teeth which have been collapsed over a infracluded deciduous teeth can disturb the arch length perimeter. In such cases, surgical approach might be necessary, although it would be difficult when teeth are severly leaned. However, an easier surgical access have been obtained by space regaining procedures, in young patients whose arch length has been shortened due to the infracluded teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.4
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• pp.382-391
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• 2019

This study was aimed to assess the new trial for minimal cavity preparation in composite restoration combined with resin infiltration, focusing at application sequence. 32 human primary molars with early carious lesions around small cavity were selected and randomly divided into two groups, according to the sequence of cavity preparation (P), composite filling (F) and resin infiltration (I) as IPF and PFI group. Each group was assessed about amount of tooth reduction, features of resin infiltration, and marginal leakage around restoration. Amount of tooth reduction evaluated using micro-CT was decreased compared with the original lesion size in both groups. Features of resin infiltration were verified under confocal laser scanning microscopy. In both groups, infiltrant resin was found on all around the composite and maintained in spite of extent of decalcification even after artificial caries induction. Marginal micro leakage assessed with silver nitrate immersion and micro-CT was found more frequently in PFI group. The technique combining resin infiltration and composite restoration might ensure better adhesion prognosis as applied by the sequence of resin infiltration, cavity preparation, and composite filling. This new trial was thought meaningful in minimizing the cavity size and contributing to minimal invasive dentistry.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.151-159
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• 2021

Since January 2019, insurance coverage for caries treatment of permanent teeth using composite resin in children aged 12 and under has started in South Korea. The purpose of this study was to compare the pattern of permanent molar composite resin restoration aged 12 and under before and after the insurance coverage from January 2009 to March 2020 in the Department of Pediatric Dentistry at Kyung Hee University Dental Hospital at Gangdong. Since the insurance coverage was started in 2019, the frequency of permanent molar composite resin restoration aged 12 and under has increased more than twice. There was a significant change in frequency of resin restoration by shape of cavity comparing before and after the insurance coverage, whereas there was no significant difference in changes by patient age, gender and position of tooth. As accessibility to the permanent tooth composite resin restoration is increased by the insurance coverage, which shows a fair survival rate, it is expected that it could be able to secure oral health in the early permanent dentition aged 12 and under.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.21-30
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• 2021

The purpose of this study is to investigate the antibacterial effects of indocyanine green (ICG) and near-infrared diode lasers on multispecies biofilms. Multispecies biofilms of Streptococcus mutans, Lactobacillus casei and Candida albicans were treated with different irradiation time using photosensitizer ICG and 808 nm near-infrared diode laser. Colony forming unit (CFU) was measured, and qualitative evaluation of biofilm was performed with confocal laser scanning microscopy (CLSM). Temperature measurement was conducted to evaluate photothermal effect. In the groups using ICG and diode laser, reduction in CFU was statistically significant, but the difference in antibacterial effect on L. casei and C. albicans with irradiation time was not significant, and similar results were confirmed with CLSM. Groups with ICG and diode laser showed higher temperature elevation than groups without ICG, and results of measured temperature were similar to the range of hyperthermia. In conclusion, ICG and near-infrared diode laser showed antibacterial effects on multispecies biofilms, but studies on protocol are necessary for clinical application.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.485-497
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• 2003

Grapefruit seed extract has been reported to have antimicrobial effect. The purpose of this study was to evaluate the antimicrobial and anti-gingivitis effect of chewing gum containing grapefruit seed extract and xylitol. 40 healthy subjects with gingivitis or early periodontitis were divided into two groups. Subjects in the experimental group chewed gum containing grapefruit seed extract and xylitol while subjects in the control group chewed gum containing only xylitol. All subjects received scaling and tooth brushing instruction. 1 week after scaling was set as baseline. Gingival index and plaque index were scored at baseline, 1 week, 2 week, 3 week and 4 week. Bleeding index, probing pocket depth and clinical attachment level were scored at baseline, 2 week and 4 week. The number of total bacteria and Streptococcus mutans in unstimulated saliva of experimental group were counted at 1 week, 2 week, 3 week and 4 week. Gingival indices of experimental group and control group at baseline, 1 week, 2 week, 3 week and 4 week were 0.850${\pm}$0.298, 0.575${\pm}$0.345, 0.533${\pm}$0.332, 0.459${\pm}$0.311, 0.408${\pm}$0.224 and 0.758${\pm}$0.379, 0.592${\pm}$0.276, 0.563${\pm}$0.281, 0.454${\pm}$0.194, 0.413${\pm}$0.199 (mean${\pm}$SD), respectively. Plaque indices of experimental group and control group at baseline, 1 week. 2 week, 3 week and 4 week were 0.497${\pm}$0.500, 0.375${\pm}$0.484, 0.332${\pm}$0.471, 0,286${\pm}$0.452, 0.210${\pm}$0.407 and 0.411${\pm}$0.492, 0.375${\pm}$0.484, 0.354${\pm}$0.479, 0.313${\pm}$0.463, 0.193${\pm}$0.395, respectively. Bleeding indices of experimental group and control group at baseline, 2 week and 4 week were 0.377${\pm}$0.177, 0.298${\pm}$0.152, 0.192${\pm}$0.108 and 0.383${\pm}$0.124, 0.318${\pm}$0.153, 0.225${\pm}$0.126, respectively. Probing pocket depth of experimental group and control group at baseline, 2 week and 4 week were 2.56${\pm}$1.00, 2.40${\pm}$0.65, 2.23${\pm}$0.64 and 2.45${\pm}$0.682.37${\pm}$0.57, 2.19${\pm}$0.57, respectively. Clinical attachment level of experimental group and control group at baseline, 2 week and 4 week were 2.58${\pm}$1.01, 2.43${\pm}$0.67, 2.26${\pm}$0.65 and 2.49${\pm}$0.70, 2.40${\pm}$0.59, 2.22${\pm}$0.62, respectively. The % of reduction of total bacteria in saliva of experimental group at 2 week, 3 week and 4 week were 46 ${\pm}$ 53%, 53 ${\pm}$ 5% and 69 ${\pm}$ 33%. The % of reduction of Streptococcus mutans count in saliva of experimental group at 2 week, 3 week and 4 week were 52${\pm}$69%, 88${\pm}$30% and 89${\pm}$17%. From these findings, it can be concluded that regular use of grapefruit seed extract /xylitol chewing gum may be effective to control and prevent gingivitis and may have caries-preventive effect.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.54-61
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• 2000

Amalgam, though a widely used dental material, does not bond to the tooth substrate Therefore, retentive preparation of the cavity is necessary. Such amalgam restorations, until corrosion products form and plug the margin, will show significant marginal leakage. Unless this is prevented early on, saliva and bacteria may enter the cavity causing postoperative hypersensitivity, dissolution and collapse of the restoration, discoloration of the margin and secondary caries, leading to shortened life-span of the restoration and pulpal pathosis. Recently, a method of restoration has been introduced whereby tooth material can be preserved, cavity margin can be sealed and preventive treatment of pit and fissure can be administered while retaining all the advantages of conventional amalgam restorations. Such sealed amalgams involve removing the carious lesion without extending the cavity for prevention and using pit and fissure sealants to seal cavity margins and pit and fissures to reduce microleakage. In this study, finishing of the amalgam and sealant application were performed after different intervals following of amalgam restoration to compare the microleakage of sealed and conventional amalgam restorations. Thirty bicuspids were prepared with Class V cavity preparations on the buccal and lingual surfaces. After amalgam placement, they were divided into the following groups and treated accordingly. Group 1 : Polishing after 24 hours Group 2 : Immediate sealant application without polishing Group 3 : No polishing, but sealant applied after thermocycling 500 times After treatment, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue kept in a $37^{\circ}C$ incubator at 100% humidity for 24 hours. The teeth were then embedded in resin and cut bucco-lingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage, The following results were obtained : 1. Group 2 showed the least microleakeage, while group 1 showed the greatest. 2. Group 1 showed significantly greater microleakage compared to group 2 (p<0.05). However, no significant differences were found between group 1 and 3(p>0.05). No significant differences in microleakage were also found between cup 2 and 3(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.119-125
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• 2009

Fusion and gemination are irregularities in tooth development. It is often difficult to differentiate between gemination and fusion and it is common to refer to these anomalies as 'double teeth'. The deciduous teeth are most commonly involved, but in 0.1% of cases permanent teeth are affected, in which case aesthetic, funtional and periodontal problems can result. Double teeth present great difficulties in management and required a multidisciplinary approach. The central groove on the labial and palatal surfaces of a double tooth is extremely prone to caries, therefore early 'fissure sealing' is essential. In permanent dentition, surgical separation of fused teeth may be possible with subsequent orthodontic alignment and restorative treatment as needed to reshape the crown. Reshaping or reduction of a double tooth with a single canal may be attempted by modifying the appearance of the labial groove and the use of composite tints but is often impossible and extraction may be the only alternative. Orthodontic treatment and prosthetic replacement is then required. Implants may be an option for adolescents. The present study describes three clinical cases of double teeth in the position of the maxillary permanent incisors. The first case demonstrates an example of multidisciplinary care including surgical intraoral hemisection, root canal therapy, restorative and orthodontic treatment. The second and third cases describe the external and internal morphology of the two fused teeth by means of three dimensional dental computer tomography.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.233-239
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• 2010

Space loss of dental arch can appear when the proper position of teeth within the dental arch changes by a certain cause, because the balance of force makes changes about tooth position as well as alignment. The causes of space loss include proximal caries, early extraction, congenital missing of a tooth and hypodontia, etc. Among those causes of space loss, congenital missing of a tooth is more rarely observed in the primary dentition than in the permanent dentition. Congenital missing in the primary dentition is associated with that in the permanent dentition. Furthermore, it can cause space problem, such as mesial tilting or drift of adjacent teeth, space loss for permanent successors and dental arch constriction, etc. Primary lateral incisors is the most commonly involved, in the maxilla rather than in the mandible, but primary canine is rarely reported. In this patient, who visited the department of pediatric dentistry at Yonsei university dental hospital, it was observed that the maxillary right primary canine was congenitally missing and an odontoma was found insteadly. However, neither the space loss for the congenitally missing primary canine nor midline deviation is remarkable during the 2-year-10-month observation period. In addition, any clinical or radiographical symptom did not occur in spite of odontoma. Therefore, surgical enucleation of odontoma is planned according to the eruption of permanent lateral incisor or canine, unless eruption failure of permanent lateral incisor or canine nor cystic change around the odontoma is occurred. Through further evaluation, space maintainer or orthodontic treatment may be necessary.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.653-660
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• 2006

Fuji VII is a glass-ionomer cement specially targeted for early protection in erupting first and second molars. Properties of Fuji VII such as very high level of fluoride release, low viscosity and no need to preliminarily etch the substrate would be useful to erupting molars with primary pit and fissure caries or hypoplastic area for preventive goal or remineralization. The purpose of this study were to evaluate remineralization of Fuji VII glass ionomer cement and to compare with one of other restorative materials such as conventional glass ionomer cement, resin-modified glass ionomer cement, compomer and composite resin. Forty-two extracted human molars were used for this study. All teeth were immersed in demineralizing solution for 48 hours after Class V cavity preparation was made on sound proximal surface. The teeth were randomly divided into six groups and restored with Fuji VII, Fuji II, Fuji II LC improved, F2000, $Filtek^{TM}$ Z250 and control group was unrestored. The middle area with $130{\pm}20{\mu}m$ thickness was separated from specimen using microtome and demineralized area was photographed under polarized microscope. Separated area was relocated to specimen and stored in artificial saliva, After four weeks, changes of demineralized area were observed and compared to them restorated immediately. The results from the this study can be summarized as follows ; 1. Fuji VII, Fuji II, Fuji II LC improved have more prominent remineralization effect than F2000, $Filtek^{TM}$ Z250, control group. 2. No significant differences in remineralization effect are seen between Fuji VII and Fuji II, Fuji II LC improved.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.411-421
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• 2006

In children, during developing occlusion stage, many studies confirm a high prevalence of gingival inflammation. Prevention, early diagnosis and treatment of gingival and periodontal disease is important because by establishing excellent oral hygiene habits in children, the risk of periodontal disease can be on the decrease in adulthood. This study evaluated the gingival conditions of 50 children$(8.5{\pm}3.1years)$ and 20 $adults(26.1{\pm}3.3 years)$ receiving clinical examination and GCF test at the pediatric dentistry of Chonbuk national university hospital in Jeonju, Korea. I estimated children's and adult's gingival states by measuring gingival crevicular fluid(GCF) using Periopaper and $Periotron^{(R)}$ 8000, gingival index, plaque index, DMFT scale. The results were as follows : 1. There are no statistical differences of GCF volume among the groups of the primary dentition, tooth erupting stage, complete eruption stage(p>0.1). But mean value of GCF is highest at the tooth erupting stage. 2. Comparing with adults, children have higher mean value of GCF volume with statistical differences (p<0.001). 3. There is statistically positive relationship between volume of GCF and gingival index (GI), plaque index(PLI) in both adults and children(GI; r=0.394, PLI ; r= 0.642). 4. There is no relationship between GCF volume and dental caries, composite resin treatments (p>0.05). But There is statistically positive relationship between GCF and orthodontic treatments(p<0.001) 5. Primary dentition has higher mean value of DMFT than permanent dentition(p<0.001). But there is no statistical relationship between GCF and DMFT (p>0.1).