KJC Korea
Journal Central

The aim of this study was to enhancing the panoramic radiograph’s clinical use for assessing mandibular measurements and formulating a function of those measurements from panoramic radiographs and lateral cephalograms in children. The panoramic radiographs and lateral cephalograms of 99 former orthodontic patients with skeletal class III malocclusion were selected. In each radiograph, gonial angles, ramus heights, and distance between lower incisors and symphysis were measured. The values of the studied parameters were compared by paired t-test, Pearson’s correlation test and regression analysis. The mean value of the gonial angle in panoramic radiographs was 125.49°, and the value in lateral cephalograms was 127.50°. The Pearson’s correlation coefficient (ρ ) between mean values of gonial angle in each radiograph was 0.945 (p < 0.001). The relationship between the gonial angle measurements obtained from each radiographs was represented as ‘Gonial angle (Lateral cephalograms) = 0.920 X Average gonial angle (Panoramic radiographs) + 12.072’ in the linear function. The coefficients of ramus heights, and distance between lower incisors and symphysis portrayed weaker correlations than gonial angles. A panoramic radiograph could be used to determine the gonial angle as accurately as a lateral cephalogram, and each gonial angle showed a strong positive relation. A panoramic radiograph is a useful tool for examining vertical growth pattern of patients, as well as a lateral cephalogram.

The aim of this study was to estimate time of biomineralization in developmental stages of rat lower incisors. Eruption length was measured. Four stages of incisor development were identified on histologic and microscopic computerized tomography (micro-CT) sections: (1) preodontoblast, (2) dentin matrix secretion, (3) enamel matrix secretion, and (4) enamel calcification. The overall eruption rate of the rat lower incisor was 600 ± 70 μm/day (mean ± SD; n = 12). The length of the enamel secretion was 4.59 ± 0.75 mm in histologic section, was 3.64 ± 0.63 mm in radiographic section, which converts to 180.4 ± 30.0 hours, 145 ± 25 hours respectively (n = 24). These findings suggested that the four biomineralizing developmental stages of the rat incisor took only several days. The significance of this animal study was to provide understanding for the rapid biomineralization process of developing rat tooth germ by analysis of tooth forming period.

This study assessed the association between ectopic eruption of the maxillary first permanent molar and skeletal malocclusion in 5- to 10-year-old children. As subjects, 786 children who attended the Wonkwang University Dental Hospital for orthodontic diagnosis were included. Children with unerupted first permanent molars or fully erupted second permanent molars were excluded. The study group demonstrated ectopic eruption of the maxillary first permanent molar, while the control group did not. Cephalometric radiographs taken between January 2003 and August 2015 were analyzed. Skeletal class III malocclusion was detected in 57.0% of the study group, which differed significantly from that in the control group (p ＜0.05). The SNA, ANB angles, and A to N-perpendicular distance were significantly smaller, whereas the A-B plane angle and APDI were significantly greater in the study group than in the control group (p ＜0.05). The SNB and mandibular plane angles were not significantly different between the groups. Thus, maxillary undergrowth is a risk factor for ectopic eruption of the maxillary first permanent molar.

This study aims to investigate the utilization status of dental services by foreign children living in Seoul and their level of satisfaction with the treatments. We developed a structured questionnaire with 35 questions, which comprised 14 questions (demographic characteristics) and 21 questions (oral hygiene and dental experience of the child). In this study, the distribution of nationality of 391 participants differed from the actual statistics in Korea. It consisted of high percentage of participants from African countries (23.6%), as well as North American countries (24.1%). In addition, the education status of most parents was above the level of college graduate. Despite the relatively high socioeconomic status of the participants, they showed minimal dental health knowledge regarding the aspect of oral hygiene. Utilization of dental health services and the types of dental clinics visited by them were similar before and after coming to Korea. The participants showed overall satisfaction with the care, but many of them expressed the need for improvement with regard to treatment fee and communication. In conclusion, foreign children living in Seoul require appropriate dental health education and governmental support to promote regular dental check-ups, to improve their overall oral health, and prevent the incidence of dental caries.

Dentinogenesis imperfecta type II (DGI-II) is an inherited disorder affecting the dentin matrix and is related to mutations in the dentin sialophosphoprotein (DSPP ) gene. The protein encoded by the DSPP gene undergoes extensive posttranslational modifications. Dentin phosphoprotein (DPP), one of the DSPP expressed products, has unique composition with highly repetitive Asp-Ser-Ser amino acid residues and is related to the maturation of dentin mineralization. We aimed to identify mutation in DSPP , including the DPP coding region, contributing to inherited dentin defects in a Korean family with DGI-II. Clinical and radiographic examinations were performed, and all five exons and exon-intron boundaries of the DSPP gene were sequenced. Additionally, allele-specific cloning for highly repetitive DPP region was performed. By sequencing and cloning, a heterozygous single nucleotide deletion (c.2688delT) was identified. The identified mutation caused a frameshift in the DPP coding region. This frameshift mutation would introduce hydrophobic amino acids instead of hydrophilic amino acids and would result in a change in the characteristics of DPP.

The purpose of this study was to compare the cariogenicity of commercially available bovine milk and low-fat milk in a biofilm model using the CDC Biofilm Reactor. Streptococcus mutans ATCC 25175 biofilms were formed on saliva coated bovine enamel slabs in a CDC Biofilm Reactor. Biofilms were exposed three times per day to one of the following materials: commercial whole milk (fat content: 3.4%), low-fat milk (fat content: 1%), or 0.9% NaCl. Medium pH was measured at different time points. After 5 days, biofilms were separated from slabs to evaluate the CFUs. The biofilm thickness was observed by confocal laser-scanning microscopy (CLSM). Enamel slab’s demineralization was assessed by measuring surface microhardness before and after the experiment. For microhardness and CFUs assessment, no significant difference was found among the three groups. All groups showed similar pattern of medium pH change and biofilm thickness. Our results showed that there was no difference in the cariogenicity between whole milk and low-fat milk. Both milks were relatively non-cariogenic compared to the control group.

The aim of this study was to investigate and compare fluoride release of giomer (Beautifil Injectable), compomer (Dyract® XP), and composite resin (Filtek™ Z350XT) through adhesive (Scotchbond Multi-Purpose) layer. A total of 20 cylindrical specimens (7 mm in diameter and 2 mm in thickness) of giomer, compomer and composite resin were prepared according to the manufacturers’ instruction (10 with adhesive and 10 without adhesive). These specimens were immersed individually in 2 mL of deionized water at 37℃. The amount of fluoride release was measured on the 1st, 3rd, 7th, 14th, 21st, and 28th day. To confirm uniform application of the adhesive layer, additional 18 specimens with adhesive were prepared and evaluated by scanning electron microscope. The giomer and compomer groups with adhesive applied showed no fluoride release until the 3rd day. However, from the 7th day, fluoride was detected. The application of dentin adhesive did not completely prevent fluoride release from giomer or compomer. Fluoride release was significantly (p < 0.05) reduced through the adhesive layer. The reduction of fluoride release was more remarkable on the giomer.

Natal teeth that are already present at birth and neonatal teeth that erupt shortly after birth may cause various complications. The purpose of this study is to evaluate the characteristics of natal/neonatal teeth in Korean infants who visited to Kyung Hee University Dental Hospital from 2006 to 2015. A retrospective review of clinical data, including the sex of the patients, chief complaints of the mothers, clinical appearances and locations of the natal/neonatal teeth, and associated complications and treatments, was collected. Overall, a total of 75 teeth were found in 48 patients and 69% of the infants had natal teeth, while 31% had neonatal teeth, all of which were mandibular incisors. Females showed more natal/neonatal teeth than males. Major reasons for visiting the dental clinic were parental anxiety, referrals from other clinics, Riga-Fede disease, and pain during breastfeeding. Extraction was the most common treatment choice; observation and grinding were also used.

This study investigated the prognosis of luxation injuries in primary teeth treated with splinting. This study retrospectively analyzed 92 children with luxation injuries to their primary teeth who were treated with splints between 2010 and 2015. Prognoses were analyzed in patients who had been followed for more than 6 months. The prognoses with splinting were based on clinical and radiographic evaluations performed during the follow-up examinations. The mean patient age was 42.1 months, and 67.4% were male. The most common cause of luxation injury was falling, and the mean splint duration was 2.4 weeks. The success rate of splinting was 58.9%. The highest rate of success was achieved following subluxation, while repositioning and splinting of lateral luxation had the lowest rate of success. Pulp necrosis was the most common unfavorable prognosis in the luxation injuries. Depending upon the type of luxation, splint therapy had acceptable prognoses and might be a feasible treatment option.

The aim of this study was to evaluate the shear bond strength (SBS) of three typical restorative materials - glass ionomer cement (GIC), resin-modified glass ionomer (RMGIC) and composite resin (CR) - to different pulp capping materials, i.e., Theracal LC™ (TLC), Biodentine™ (BD), and ProRoot™ white MTA (WMTA). 90 acrylic blocks with a center hole were prepared. The holes were completely filled with three pulp capping materials (TLC, BD, and WMTA), with 30 specimens per capping material. The samples were then randomly divided into 3 subgroups of 10 specimens each and were overlaid with GIC, RMGIC, or CR. A total 9 specimen groups were prepared. The SBS was assessed using a universal testing machine. Kruskal-Wallis test and Mann-Whitney’s test were performed to compare the SBS among the subgroups (p < 0.05). After the SBS test, the fractured surfaces were examined under a stereomicroscope at a magnification of 25×. The highest and lowest SBS values were recorded for TLC-CR and TLC-GIC, respectively. With regard to the SBS to the three pulp capping materials, CR was found to be superior to RMGIC and GIC. BD showed a higher SBS compared to TLC and WMTA when used with GIC.

This study aimed to investigate the prevalence and distribution of enamel hypomineralization, including molar-incisor hypomineralization (MIH), among adolescents and assess their correlation with esthetic satisfaction. A total of 1371 adolescents between the ages of 14 and 16 years in Yangsan city were evaluated for enamel hypomineralization, including MIH, according to the European Academy of Paediatric Dentistry (EAPD) criteria. In a parallel survey, esthetic satisfaction about anterior teeth and its correlation with incisor enamel hypomineralization were analyzed. The prevalence of MIH was 13.8% (n = 189), while that of hypomineralization in any permanent tooth was 23.2% (n = 318), which was substantially greater compared to the national prevalence of MIH. Mandibular first molars exhibited the highest prevalence of hypomineralization, followed by maxillary central incisors and mandibular second molars. Among anterior teeth, the most frequently affected site was the incisal edge of maxillary central incisors. A high degree of hypomineralization in anterior teeth was associated with a high demand for esthetic treatment.

Pre-eruptive intracoronal resorption (PEIR) is a rare radiolucent lesion often located within the dentin and adjacent to the dentin-enamel junction, underneath the occlusal aspect of the crowns of unerupted teeth. The treatment approaches for these lesions involved with unerupted teeth have been known as to be relatively simple; depending on the extent of resorption, follow-up or restoration can be performed after surgical exposure. However, once the tooth is exposed to the oral cavity after eruption, it becomes highly vulnerable to the development of carious lesions. Thus, immediate intervention is required in such cases; failure to address it may result in the need for more complex treatments including endodontic therapy. The aim of this case report was to describe the characteristics of PEIR and the clinical management of the impacted immature permanent teeth diagnosed with PEIR.

Hydrocephalus is a condition in which the volume of cerebrospinal fluid in the cerebral ventricles is abnormally elevated. Hydrocephalus patients may show macrocephaly and delayed development. Ventriculoperitoneal shunt is the most commonly used treatment but ventriculoatrial shunt is another treatment option. This report discusses the dental management process employed for a 7-year, 6-month old patient with ventriculoperitoneal shunt-treated hydrocephalus. This patient showed dental caries on the deciduous molars, facial swelling, macrocephaly and delayed development. Pulpectomy was performed on the deciduous molars under nitrous oxide sedation and mild protective stabilization. This patient did not appear to have any specific complications until the latest follow-up and was scheduled for the management of overall oral hygiene, development of permanent teeth, and craniofacial asymmetry through periodic follow-up. During dental treatment of shunt-treated patients, care should be taken to avoid applying excessive force to the catheter running along the patient’s neck to prevent the displacement of the catheter. A referral to a neurosurgeon is recommended for patients with ventriculoatrial shunts for prophylactic antibiotics. As hydrocephalus patients grow, they may show craniofacial asymmetry or differences in the calcification of the permanent teeth, and require periodic oral and craniofacial assessment.

Marsupialization and decompression constitute a well-established procedure for treating cavitary bone lesions of the jaw. The technique can be a primary treatment option, especially for pediatric patients with large cysts or lesions involving vital anatomical structures, such as a developing tooth germ. In this procedure, a decompression stent, such as a customized acrylic obturator or space-maintaining appliance, silicone tube, or nasal cannula, is inserted to maintain the patency of the cyst. However, this may cause clinical problems, such as irritation or trauma to the adjacent tissues, as well as discomfort to the patient, or failure of the stent due to cyst shrinkage. It can also be a reason for patient noncompliance. In the cases described here, a minimally invasive marsupialization technique using a metal tube made from a 16-gauge needle was used for odontogenic cysts in pediatric patients associated with unerupted teeth. Through this method, the lesions were removed, with patient cooperation, and the cyst-associated teeth erupted spontaneously.

Cardiopulmonary resuscitation (CPR) is an emergency treatment that stimulates blood circulation and breathing when the function of the heart stops or stops breathing. CPR can be divided by basic life support (BLS) and advanced life support (ALS). BLS involves the use of chest compression to force the blood flow to the main organs, rescue breathing to improve the breathing to the respiratory failure patient and the use automated external defibrillator (AED). The categories of advanced life support include advanced cardiovascular life support (ACLS) for adult and pediatric advanced life support (PALS) for children. In the treatment of dental care for children, which is extremely difficult to deal with, and for a variety of reasons, the use of sedation is considered to treat the children who are unlikely to cooperate with dentistry. This is why there is an increasing possibility of an emergency situation involving cardiac arrest. PALS includes the BLS, and it presents a systematic algorithm to treat respiratory failure, shock and cardiogenic cardiac arrest. In order to manage emergency situations in the pediatric dental clinic, respiratory support is most important. Therefore, mastering professional PALS, which includes respiratory care and core cases, particularly upper airway obstruction and respiratory depression caused by a respiratory control problem, would be highly desirable for a physician who treats pediatric dental patients. Regular training and renewal training every two years is necessary to be able to immediately implement professional skills in emergency situations.