KJC Korea
Journal Central

This study aimed to assess the skeletal age of skeletal maturational indicator (SMI) and middle phalanx of the middle finger (MP3) stages and to predict the SMI and MP3 stages corresponding to pubertal growth spurt in boys and girls respectively. The skeletal age was assessed from hand-wrist radiographs of 363 children (182 boys, 181 girls) aged 7 to 16 years by radiologists using the Korean standard bone age chart. Also, SMI and MP3 stages were evaluated from the radiographs. From these records, the mean skeletal age of SMI and MP3 stages was calculated. The stages including pubertal growth spurt were SMI 4 - 5, MP3 FG - G stages in boys and SMI 3 - 4, MP3 F - FG stages in girls.

The purpose of this study was to examine dental complications and to evaluate the effects of initial treatment age, treatment modalities, and treatment duration on the disorder after radiation and chemotherapy in pediatric cancer patients. For 93 children with clinical and radiographic data, the number of teeth, the morphology of teeth, the shape of the roots, and development status of the dentition were evaluated. Dental development disorders were found in 61.3% of the children. The mostly found abnormality was root deformity with the prevalence of 31.2%. In children submitted to the therapy before the age of 6, the number of missing teeth (p = 0.029) and microdontia (p = 0.003) were greater compared to the children who started to receive the treatment after the age of 6. The combination of radiation and chemotherapy showed significantly greater incidences of missing teeth (p = 0.030), microdontia (p = 0.046), and root deformity (p = 0.009) when compared with the sole application of chemotherapy. When the children were submitted to anticancer therapy for 18 months or longer duration, greater number of missing teeth (p = 0.032), microdontia (p = 0.011), root deformity (p = 0.025), and total number of teeth affected (p = 0.036) were observed compared with duration less than 18 months. The number of dental abnormalities increased when the children were treated at earlier ages, with combination of radiation and chemotherapy, and for longer period of time.

This study aimed to investigate the correlation between maxillary canine’s dental maturity and skeletal maturity of growing children. Cephalometric radiographs, hand-wrist radiographs and panoramic radiographs of 299 children aged 6 - 17 years were analyzed to measure the cervical vertebral maturation stages (CVMS), skeletal maturity indicators (SMI) and Demirjian index (DI). Spearman correlation test was used to analyze the correlation between dental maturity and skeletal maturity. There was significant positive correlation between the DI and CVMS in both boys and girls (p = 0.000). Similarly positive correlation was found between the DI and SMI (p = 0.000). The results of this study suggest that the dental maturity of maxillary canine can be used as auxiliary maturity indicator in growing children.

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice. Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either Vitapex® (n = 44), Metapex® (n = 44), or Metapaste® (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher’s exact test and Kruskal-Wallis test were used to compare the tested groups. In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction. Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.

This study was performed to evaluate clinical use of laser fluorescence (LF) to identify early childhood caries lesions suitable for applying resin infiltration. 20 exfoliated primary molars with proximal caries were selected and cut buccolingually cross the central pit for regarding the mesial and distal surfaces respectively. 27 specimens corresponding to ICDAS code 1 and 2 were selected and the LF values were measured. When infiltrant resin was applied, double staining for microscopy detection has done simultaneously. Tooth samples were sliced with 0.7 mm thick. The maximum lesion depth, maximum penetration depth, and average penetration rate were measured from the confocal scanning laser microscope image. Pearson correlation analysis was performed. The intraclass correlation coefficient of LF values shows excellent agreement. LF values had positive correlation with penetration rate, but not lesion depth and penetration depth. Significant correlation between LF readings and penetration rate was verified in deep enamel caries and dentin caries except shallow enamel caries. Infiltrant resin could penetrate with a higher rate and LF values could be increased in more active caries lesions. In assessing radiologically similar caries lesion, laser fluorescence might be useful for identifying caries activity.

The purpose of this study was to evaluate effect of saliva decontamination procedures on microtensile bond strength (MTBS) of 1-step self-etching adhesives to dentin of primary posterior teeth. 63 sound primary-posterior teeth were randomly divided into 3 groups according to different kinds of 1-step selfetching adhesives: Scotchbond™ Universal Adhesive (SBU), All-Bond Universal® (ABU), and Tetric® N Bond Universal (TBU). Each group was randomly categorized into 7 subgroups: (I) application of adhesive without saliva contamination (control); (II - IV) contamination by saliva before photopolymerization; (V - VII) contamination by saliva after photopolymerization; (II, V) decontamination by drying; (III, VI) decontamination by washing and drying; (IV, VII) decontamination by washing, drying, and reapplication of adhesive. All samples were cut into the blocks. At least 15 blocks were tested for each subgroup. For SBU and ABU, the MTBS values of subgroups (I, IV, VII) were significantly higher than those of subgroups (II, III, V, VI). For TBU, the MTBS values of subgroups (I, IV) was significantly higher than those of subgroup (II, III, V, VI). The MTBS of 3 adhesives was reduced by saliva contamination. The adhesive strength on dentin of primary posterior teeth was restored by reapplication of the adhesives after washing and drying.

The purpose of this study was to evaluate the relationship between Body Mass Index (BMI) and dental caries by considering related factors in Korean children and adolescents. A total of 2,874 children, aged from 2 to 18, who participated in the Korea National Health and Nutrition Examination Survey 2013 - 2015 were included. BMI (kg/m²) was calculated, and participants were categorized into 4 groups using age and gender specific criteria. Decayed and filled teeth index were obtained. There were statistically significant differences in DMFT index between overweight group and other groups (p < 0.01). Underweight group showed the highest mean DMFT index compared to other groups. These findings suggest that children in obesity and underweight group tend to have more caries than normal group in this study.

As a common side effect of fixed orthodontic treatment, demineralization of the enamel adjacent to the bracket and band occurs in patients with poor oral hygiene. The purpose of this study was to investigate what is the most effective method to prevent demineralization around the fixed orthodontic appliance among various methods using fluoride. 80 extracted bovine incisors with a healthy surface were classified into four groups as experimental materials: (Group I) Control group, (Group II) V varnishTM, (Group III) Tooth Mousse Plus®, (Group IV) VanishTM XT. After treatment for each group, mineral loss and Vickers surface microhardness were measured at 0, 30, 60 and 90 days after demineralization in artificial carious solution. Mineral loss was the lowest in group IV, followed by group II and group III, which showed a significant difference. The surface microhardness was the lowest in group IV, followed by group II and group III, which showed a significant difference. Through this study, group IV showed the best effect to prevent enamel demineralization around the bracket. Group III showed significant prevention of enamel demineralization compared with the control group, but the effect was less than that of the other groups.

This study was performed to determine the effectiveness of oral health education program with a home-using portable device according to the individual oral health status in children. 58 children who were 6 - 12 years old were included in this study. All subjects were affiliated to moderate or high caries risk group based on caries risk test. They were divided into 2 groups: (I) home-using portable device group (II) control group. Both groups were evaluated with simple plaque score (SPS) using camera type quantitative light-induced fluorescence device and educated with identical oral health education methods. Subjects in group I were demanded to use a home-using portable device. After 1 month, both groups were re-evaluated. Cariview score that can reflect the acidogenic potential of plaque bacteria was statistically reduced in both groups (p < 0.001). There was a statistically significant difference between two groups in the change of Cariview score (p = 0.022). In group I, the decrease was larger than that in group II. There was no statistically significant difference in the change of SPS (p = 0.937). Oral health education improved oral hygiene status in children. However, this study confirmed that it was much more effective to improve oral health status in children with a home-using portable device in their daily oral hygiene care.

The purpose of this retrospective study was to evaluate the survival rate of composite resin restorations in permanent first molars in pediatric patients focusing on the influence of risk factors related to patients and teeth. 172 patients (6 - 12 years old) who had their permanent first molars restored with composite resin from July 2010 to July 2012 were investigated. From the dental records, the influence of the risk factors on the survival of restorations was assessed. Location of teeth, classification of cavities, patients’ age and caries risk were included as risk factors in this study. The caries risks of patients were evaluated by the value of the decayed-missing-filled teeth index with the records of patients taken at 5 years old. Among 354 restorations, 272 restorations retained and 82 restorations were replaced. The overall cumulative survival rate at 5 years was 73.9%. The main reason for replacement of restorations was secondary caries (81.7%). Patients with older age group and with lower caries risk group showed higher survival rate of restorations. No statistically significant influence was detected between the survival rates and the possible risk factors : location of teeth, patients’ age and caries risk. The survival rate of restorations was significantly affected by the classification of the cavities (p = 0.002).

The purpose of this study was to identify which combination of zirconia crowns and cements is most similar in color to the maxillary primary incisors by varying the color of zirconia crowns, crown thickness, and shade of cements. Prefabricated zirconia crowns in 3 shades and crowns fabricated using 6 types of zirconia blocks were used in this study. These were filled with A2-shade or translucent-shade resin cement and the L *, a *, and b * values were calculated using a spectrophotometer. The color differences between the natural teeth and the zirconia crowns were assessed. The shade of the final restoration was more similar to that of the natural teeth using A2‑shade than translucent-shade resin cement. Application of A2-shade cement to a 0.5-mm-thick crown fabricated from a smile series 2 zirconia block resulted in the color most similar to that of the natural teeth. A2-shade resin cement is recommended for zirconia crown restoration in anterior primary teeth compared to TR-shade resin cement for more esthetic restoration. Since restorations with Nusmile zirconia crowns were not esthetically favorable in terms of shade, improvement of the shade characteristics of the product or development of a new kind of zirconia crown is required.

The purpose of this study is to analyze the changes in patient distribution and practice pattern resulted from changes of socioeconomic circumstances. From January 2008 to December 2017, information about patient distribution and practice pattern was collected and reviewed. Both the number of new patients and revisiting patients increased. The average age of new patients showed a declining trend. Children aged between 0 and 6 had the majority. In case of restorative treatment, the use of composite resin decreased, whereas resin modified glass ionomer increased. As to pulp treatment of primary tooth, the proportion of pulpectomy increased significantly, but decreased in pulpotomy. The results showed an increase in the treatments under sedation and general anesthesia and with the use of midazolam and nitric oxide increased after 2014.

The aim of this study was to analyze cells from human dental pulp tissue of impacted supernumerary teeth as stem cells with flow cytometry. Human dental pulp cells from 15 supernumerary teeth were identified their characteristics as stem cells by expression of mesenchymal stem cell markers through flow cytometry analysis at passage 3 and passage 10. Cluster of differentiation (CD) 73, CD 90, CD 34, CD 45 and STRO-1 cell surface markers were used to figure out characteristics of dental pulp stem cells from supernumerary teeth. At passage 3, the cell population showed positive expression of CD 73, CD90 and STRO-1, lacked expression of CD 34 and CD 45. At passage 10, CD 73, CD 90 and STRO- 1 showed positive expression while CD 34 and CD 45 showed negative expression. This study indicated that dental pulp stem cells of supernumerary teeth had the properties of mesenchymal stem cells at both early and late passage. Impacted supernumerary teeth could be considered as a noble source of stem cells because of rapid growth and maintaining characteristics of stem cells until late passage.