Ki-Tae Park

Mutations in DDX58, which Encodes RIG-I, Cause Atypical Singleton-Merten Syndrome

Singleton-Merten syndrome (SMS) is an autosomal-dominant multi-system disorder characterized by dental dysplasia, aortic calcification, skeletal abnormalities, glaucoma, psoriasis, and other conditions. Despite an apparent autosomal-dominant pattern of inheritance, the genetic background of SMS and information about its phenotypic heterogeneity remain unknown. Recently, we found a family affected by glaucoma, aortic calcification, and skeletal abnormalities. Unlike subjects with classic SMS, affected individuals showed normal dentition, suggesting atypical SMS. To identify genetic causes of the disease, we performed exome sequencing in this family and identified a variant (c.1118A>C [p.Glu373Ala]) of DDX58, whose protein product is also known as RIG-I. Further analysis of DDX58 in 100 individuals with congenital glaucoma identified another variant (c.803G>T [p.Cys268Phe]) in a family who harbored neither dental anomalies nor aortic calcification but who suffered from glaucoma and skeletal abnormalities. Cys268 and Glu373 residues of DDX58 belong to ATP-binding motifs I and II, respectively, and these residues are predicted to be located closer to the ADP and RNA molecules than other nonpathogenic missense variants by protein structure analysis. Functional assays revealed that DDX58 alterations confer constitutive activation and thus lead to increased interferon (IFN) activity and IFN-stimulated gene expression. In addition, when we transduced primary human trabecular meshwork cells with c.803G>T (p.Cys268Phe) and c.1118A>C (p.Glu373Ala) mutants, cytopathic effects and a significant decrease in cell number were observed. Taken together, our results demonstrate that DDX58 mutations cause atypical SMS manifesting with variable expression of glaucoma, aortic calcification, and skeletal abnormalities without dental anomalies.

Cephalometric Characteristics of Korean Children with Class III Malocclusion in the Deciduous Dentition

OBJECTIVEnTo compare the cephalometric characteristics of children with Class III malocclusion to those of children with normal occlusion during the deciduous dentition phase.nnnMATERIALS AND METHODSnCephalometric measurements of 27 children (mean age: 5.03 years) diagnosed with Class III malocclusion were compared with 32 children (mean age: 4.85 years) diagnosed with normal occlusion in the following four categories: sagittal skeletal analysis, vertical skeletal analysis, dentoalveolar analysis, and soft tissue analysis.nnnRESULTSnSignificant differences were seen in all categories except vertical skeletal analysis. Sagittal skeletal measurements included ANB (Class III group: -0.91 +/- 1.60; normal group: 5.28 +/- 1.29), facial convexity (Class III group: 0.47 +/- 4.32; normal group: 13.65 +/- 3.44), Wits appraisal (Class III group: -5.54 +/- 2.36; normal group: -0.84 +/- 1.91), and A to N-perpendicular (Class III group: -2.94 +/- 3.05; normal group: 0.78 +/- 2.53). Dentoalveolar measurements included U1 to NA (Class III group: 11.98 +/- 5.25; normal group: 8.12 +/- 5.43), IMPA (Class III group: 81.34 +/- 7.40; normal group: 86.57 +/- 5.67), and interincisal angle (Class III group: 152.65 +/- 8.82; normal group: 145.03 +/- 7.34). Soft tissue measurements included soft tissue convexity (Class III group: 2.47 +/- 4.20; normal group: 12.71 +/- 3.95), nasofacial angle (Class III group: 22.68 +/- 4.22; normal group: 26.24 +/- 3.84), and upper lip to esthetic plane (Class III group: -0.65 +/- 2.74; normal group: 3.07 +/- 1.90).nnnCONCLUSIONSnThere are significant differences between the craniofacial patterns of normal children and those of children with Class III malocclusion that can be identified with cephalometric analysis as early as the deciduous dentition phase.

Evaluation of Alveolar Bone Support of the Permanent Canine in Cleft and Noncleft Patients

Objective: To quantitatively compare the alveolar bone support ratio of the permanent canine in cleft patients who received secondary alveolar bone graft with that of the population without clefts. Design: Retrospective study utilizing periapical radiographs of the subjects with and without clefts. Setting: Hospital and university based. Patients: Eighteen unilateral and 9 bilateral cleft patients who had secondary bone graft procedures. Main Outcome Measures: Alveolar bone support of the permanent canine utilizing the ratio of bone height to root length. Results: Average bone support for the permanent canine was 88.55% in patients with clefts and 95.59% in patients with no history of clefts. This difference was statistically significant. There was no statistically significant difference in alveolar bone support ratio between the unilateral and bilateral cleft patients. Conclusions: Although alveolar bone support was significantly higher in the noncleft control group, a successful level of alveolar bone support was achieved for the permanent canine on the cleft site after secondary bone graft. There was no difference in alveolar bone support achieved for the permanent canine whether the type of the cleft was unilateral or bilateral.

Three‐dimensional space changes after premature loss of a maxillary primary first molar

BACKGROUNDnA space maintainer is generally preferred when a primary first molar is lost before or during active eruption of the first permanent molars in order to prevent space loss. However, controversy prevails regarding the space loss after eruption of the permanent first molars.nnnAIMnThe purpose of this study was to examine spatial changes subsequent to premature loss of a maxillary primary first molar after the eruption of the permanent first molars.nnnDESIGNnThirteen children, five girls and eight boys, expecting premature extraction of a maxillary primary first molar because of caries and/or failed pulp therapy, were selected. Spatial changes were investigated using a three-dimensional laser scanner by comparing the primary molar space, arch width, arch length, and arch perimeter before and after the extraction of a maxillary primary first molar. Also, the inclination and angulation changes in the maxillary primary canines, primary second molars, and permanent first molars adjacent to the extraction site were investigated before and after the extraction of the maxillary primary first molar in order to examine the source of space loss.nnnRESULTSnThere was no statistically significant space loss on the extraction side compared to the control side (P = 0.33). No consistent findings were seen on the inclination and angulation changes on the extraction side.nnnCONCLUSIONSnThe premature loss of a maxillary primary first molar, in cases with class I molar relationship, has limited influence on the space in permanent dentition.

Retrospective analysis of the factors influencing mesiodentes eruption

AIMnThis study aimed to evaluate the factors that predict the spontaneous eruption of mesiodens.nnnDESIGNnFrom the records of 431 patients (346 boys and 85 girls, average age 8.8 years) who visited Samsung Medical Center from January 2002 to December 2006, 471 mesiodentes were reviewed. The eruption rate was investigated according to the width/length ratio, angulation, location, and shape determined from periapical or panoramic radiographs.nnnRESULTSnThe regression model showed that the width/length ratio and angulation were important determinants influencing the eruption of mesiodentes (P < 0.001, Pearsons r = 0.619). The location of the mesiodentes also affected their eruption (P < 0.01). However, no significant relationship was detected between the shape and eruption rate of mesiodentes (P > 0.05).nnnCONCLUSIONSnA lower probability of spontaneous eruption existed when the tooth had a greater angulation, shorter length, and wider width. Spontaneous eruption occurs more often when the mesiodens is located between the permanent incisors.

Surgical Management of Dentigerous Cyst for Preserving Permanent Tooth Buds

Dentigerous cyst is the most common developmental odontogenic cyst of the jaw which is associated with unerupted teeth. Treatment modalities range from enucleation to marsupialization. Enucleation is the process in which the cyst is completely removed, and this is usually indicated for smaller lesions. Larger cysts can be treated by marsupialization, which is a process that consists of making a surgical cavity on the wall of the cyst, emptying its content and maintaining the continuity between the cyst and the oral cavity. This procedure allows decompression of the cyst, regeneration of the bone-defected area, and also lets the wall of the cyst change into normal mucosa. This technique will protect adjacent structures and will promote spontaneous eruption of succedaneous teeth previously surrounded by the cyst. These are two case reports of a 5-year-old and an 11-year-old boy with dentigerous cysts found regarding supernumerary tooth and pulpotomized mandibular primary molars, respectively. Due to the large size of the cysts, both cases were treated with marsupialization. This case report shows that in cases regarding large-sized dentigerous cysts, marsupialization can be an effective surgical technique that promotes spontaneous eruption of cyst-involved succedaneous teeth and the preservation of adjacent teeth.

EFFECT OF SUPPLEMENTARY INTRANASAL MIDAZOLAM ON ORAL SEDATION OF CHILDREN

Effect of supplementary intranasal midazolam on oral sedation of children The purpose of this study was to compare the cardiopulmonary parameters of two sedation regimens during dental treatment: (1) Oral chloral hydrate(CH) and hydroxyzine(HZ) with nitrous oxide-oxygen() inhalation(CH-HZ group); (2) Oral chloral hydrate(CH) and hydroxyzine(HZ) with nitrous oxide-oxygen() inhalation and supplementary intranasal(IN) midazolam administration(MIDA group). Among the patients of OO hospital who received dental treatment under sedation over the past 5 years, 44 patients were selected for each group of CH-HZ and MIDA according to their age, gender and weight. Following parameters that were recorded every 5 minutes were compared: 1) Heart rate(HR) 2) saturation 3) End tidal carbon dioxide concentration() 4) Respiratory rate(RR) 33 patients of Group MIDA who have complete data of 15 minutes before and after supplementary IN midazolam administration were selected. And measurements 15 minutes before and after midazolam administration in same patient were evaluated. The results were as follows: 1. Heart rate was significantly higher in MIDA group than in CH-HZ group, but it was within normal range. 2. Comparing HR, saturation, EtCO2, RR between before and after of supplementary IN midazolam administration in the same patient, the differences were not statistically significant.

AUTOTANSPLANTATION OF IMPACTED MAXILLARY CANINES: CASE REPORTS

Maxillary canine impaction is a common eruption problem in children. Impaction frequently involves further complications such as root resorption of adjacent teeth, cyst formation and migration of the neighboring teeth, etc. Various treatment modalities include extraction of preceding deciduous canine, orthodontic traction, and surgical extraction followed by immediate replantation of the extracted tooth at the proper position(autotransplantation). Autotransplantation is considered as the treatment of choice when surgical exposure and subsequent orthodontic traction are difficult or impossible due to unfavorable impacted position. The prognosis of autotransplantation is affected by the degree of apex formation, surgical procedures performed, timing of root canal treatment, and length of stabilization period. In these two cases presented, the patients with unerupted maxillary canine were treated with autotransplantation. One case was thought that guidance of eruption by orthodontic traction was difficult because of its unfavorable impacted position. In the other case, parents didn`t agree to treat by orthodontic traction, therefore autotransplantation was done. In both cases, autotransplantation was carried out following root canal treatment and orthodontic treatment, and both cases have demonstrated to be successful to this day.

Effects of Facemask Therapy for Class III Malocclusions in Patients with Different Vertical Skeletal Patterns

The purpose of this study was to evaluate the skeletal and dentoalveolar effects of facemask therapy and to compare the anchorage of a bonded expander in patients with Class III malocclusion and different vertical skeletal patterns. Twenty subjects with Class III malocclusion were included in this study and were treated with a facemask and bonded expander. Based on the FMA, subjects were divided into two groups of 10 patients each: a high vertical group (HV; mean FMA ) and an average vertical group (AV; mean FMA ). Lateral cephalograms were taken and evaluated before and after treatment. In both groups, forward movement of the maxilla and backward rotation of the mandible were observed after treatment, with no statistical differences between the groups. Vertical skeletal variables increased in both groups, but the increase of FMA was significantly larger in the HV group than the AV group. Mesial movement of maxillary molars and proclination of maxillary incisors which indicate anchorage loss of bonded expander were observed in both groups, with no significant differences between the groups. In conclusion, facemask therapy resulted in effective maxillary protraction in both HV and AV groups. However, the open bite tendency was increased more in the HV group.The purpose of this study was to evaluate the skeletal and dentoalveolar effects of facemask therapy and to compare the anchorage of a bonded expander in patients with Class III malocclusion and different vertical skeletal patterns. Twenty subjects with Class III malocclusion were included in this study and were treated with a facemask and bonded expander. Based on the FMA, subjects were divided into two groups of 10 patients each: a high vertical group (HV; mean FMA ) and an average vertical group (AV; mean FMA ). Lateral cephalograms were taken and evaluated before and after treatment. In both groups, forward movement of the maxilla and backward rotation of the mandible were observed after treatment, with no statistical differences between the groups. Vertical skeletal variables increased in both groups, but the increase of FMA was significantly larger in the HV group than the AV group. Mesial movement of maxillary molars and proclination of maxillary incisors which indicate anchorage loss of bonded expander were observed in both groups, with no significant differences between the groups. In conclusion, facemask therapy resulted in effective maxillary protraction in both HV and AV groups. However, the open bite tendency was increased more in the HV group.

A Comparative Study of Facemask Therapy with Two Types of Bonded Expander

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.