Surface Roughness and Cariogenic Microbial Adhesion after Polishing of Smart Chromatic Technology-based Composite Resin / 대한소아치과학회지

This study compared the surface roughness and microbial adhesion characteristics of Omnichroma, a novel composite resin developed using “smart chromatic technology”, with those of two other conventional composite resins with different filler compositions. A total of 144 specimens were fabricated using 3 types of composite resins: Omnichroma (nano-spherical), Filtek Z350XT (nanofill), and Tetric N-Ceram (nanohybrid) and, divided into 3 groups of 48. Finishing was performed using tungsten carbide burs. Specimens were then divided into 3 subgroups using different polishing methods: Control, SofLex, and PoGo. Surface roughness was analyzed quantitatively and qualitatively using an atomic force microscope and a scanning electron microscope. Microbial adhesion was assessed by culturing Streptococcus mutans on the specimens for 24 hours and then measuring colony-forming units attached to the upper surface. The surface roughness (Ra) of Omnichroma was 0.123 μm after finishing, and it exhibited a smooth surface compared to the other resins. However, after polishing, there were no significant differences in the surface roughness between the three composite groups, regardless of the polishing methods. The surfaces of the Control subgroups were significantly rougher than those of the SofLex subgroups in all 3 composite groups. However, except for Tetric N-Ceram, there were no significant differences between the Control and PoGo subgroups in the other composite groups. Microbial adhesion assessment showed no significant differences between any of the 3 composite resin subgroups; however, Omnichroma exhibited higher microbial adhesion than the other two composites. No significant correlation was observed between surface roughness and microbial adhesion.

Evaluation of the Color Adjustment Potential of Single-Shade Composite Resin in Primary Teeth / 대한소아치과학회지

Restoring composite resins with the optimal shades for all primary teeth is a great challenge for pediatric dentists. A newly developed single-shade composite resin can exhibit a color similar to that of the surrounding tooth structure based on the structural color phenomenon. This study aims to evaluate the color adjustment potential (CAP) of a single-shade composite resin compared to conventional multi-shade composite resins in primary teeth. A single-shade composite resin and two conventional multi-shade composite resins were included in this study. Two types of specimens, a single specimen and a dual specimen, were evaluated. For single specimens, duplications of the primary second molar denture teeth were made using experimental composite resins. For dual specimens, cavities were prepared on the buccal surfaces of extracted primary second molars and restored with experimental composite resins. The L*, a*, and b* values were measured using a colorimeter for the extracted teeth and specimens. The mean ΔEab* values for single and dual specimens and CAP were calculated. Bonferroni post-hoc analysis was performed to confirm the statistical significance between the ΔEab* and CAP values of the experimental resins. Among the single specimens, the single-shade composite resin showed significantly higher ΔESingle compared to other composite resins (p < 0.0167). There was no significant difference between ΔEDual for all experimental resins. The single-shade composite resin showed highest CAP compared to other multi-shade composite resins. A single-shade composite resin exhibited the most prominent color adaptability compared to other conventional multi-shade composite resins for primary second molars. A single-shade composite resin can simplify shade matching and provide esthetic outcomes for the restoration of primary second molars.

Dynamic Range and Neural Response Threshold in Cochlear Implant Mapping Can Be Useful in Predicting Prognosis Related to Postoperative Speech Perception

Background and Objectives@#To analyze mapping changes in dynamic range (DR) and neural response threshold (NRT) as prognostic factors for cochlear implant (CI). To analyze whether postoperative speech perception performance could be predicted using DR change and initial NRT. @*Subjects and Methods@#The speech comprehension data of 33 patients with CI were retrospectively analyzed after 1, 3, 6, and 12 months of device use. All subjects were adult, postlingually hearing-impaired, and Cochlear Nucleus CI users. Speech perception performance was evaluated using aided pure tone audiometry, consonant, vowel, one-word, two-word, and sentence tests. @*Results@#The averages of initial NRT and DR changes were 197.8±25.9 CU (104–236) and 22.2±18.4 CU (-15–79), respectively. The initial DR was 40.8±16.6 CU. The postoperative DR was 50.3±16.4 CU at 3 months, 58±12.3 CU at 6 months, and 62.9±10.4 CU at 12 months. A gradual increase of DR was observed during the first year of CI. Compared with the initial DR, significant increases in DR were observed at 3 (p<0.05), 6 (p<0.001), and 12 (p<0.001) months. Compared with initial speech performance outcomes, a significant gain in all performance outcomes was achieved at 12 months (p<0.001). @*Conclusions@#Patients with low NRT after CI surgery could initially set DR to a wider range and had better final speech perception outcomes. Conversely, patients with high NRT after CI surgery had to set up a gradual increase in DR while adjusting the T-C level, and the final speech perception outcomes were worse. DR and NRT, the main CI mapping variables, can help predict prognosis related to speech perception outcomes after CI surgery. In conclusion, the post-CI speech perception is better with a lower initial NRT, wider final DR, or younger age.

Surface Roughness of Dentin and Formation of Early Cariogenic Biofilm after Silver Diamine Fluoride and Potassium Iodide Application / 대한소아치과학회지

This study aimed to evaluate the effect of silver diamine fluoride (SDF) and potassium iodide (KI) on the formation of cariogenic biofilm and surface roughness in vitro. A total of 48 bovine dentin specimens with artificially induced caries were prepared and divided into 3 groups of 16: untreated control, SDF-treated, and SDF-treated followed by KI (SDFKI). Ten specimens from each group were used to observe microbial adhesion. Multispecies cariogenic biofilms including Streptococcus mutans , Lactobacillus casei , and Candida albicans were cultured on the specimens. Microbes were cultured for 24 hours, and the colony-forming unit was calculated. The remaining specimens were observed by atomic force microscope and scanning electron microscope (SEM). The number of bacteria was significantly lower in the SDF and SDFKI groups. KI did not inhibit the antibacterial activity of SDF significantly. SEM images showed particles generated after SDF and SDFKI application were deposited on the dentin, but there was no significant difference in surface roughness between the 3 groups. This study confirmed that SDF and SDFKI application did not have a significant effect on the surface roughness of dentin, but effectively inhibited the formation of the early cariogenic bacterial film after 24 hours compared to the control.

Recovery of Streptococcus Mutans Biofilm after Photodynamic Therapy with Erythrosine and LED Light Source / 대한소아치과학회지

The aim of this study was to evaluate the effects of erythrosine-mediated photodynamic therapy (PDT) on Streptococcus mutans biofilm recovery by counting its colony-forming units (CFUs) and via confocal laser scanning microscopy analysis at different time points following PDT. In PDT, photosensitizer was an erythrosine. S. mutans ATCC25175 biofilms were irradiated using an LED curing light. Chlorhexidine (CHX) was used as positive control. After each antimicrobial treatment, samples were cultured to allow biofilm recovery. Viability was measured by calculating the CFU counts after treatment and after every 3 hours for up to 24 hours. Immediately after treatment, the PDT and CHX groups showed equally significant decreases in S. mutans CFU counts compared to the negative control. After 12 hours of reculture, the PDT group showed no significant difference in the decrease in CFU count compared to the negative control, whereas the CHX group showed significantly lower CFU counts throughout the 24-hour period. Erythrosine-mediated PDT can effectively inhibit S. mutans biofilm formation. However, biofilm recovery occurred earlier in the CHX group after PDT. This study provides insights into the clinical effectiveness of PDT in preventing dental caries.

Assessment of Fluoride Release through Dentin Adhesive in the Alkasite Restorative Material and Giomer / 대한소아치과학회지

This study evaluated the fluoride release of alkasite restorative material (ARM) and giomer penetrating the dentin adhesive layer.Twenty specimens were prepared for each restorative material, and dentin adhesive with uniform thickness was applied to half of them. The prepared specimens were placed in a polyethylene tube containing 2.0 mL of deionized water and deposited in a 37.0°C water bath for the study duration. The amount of fluoride release was measured on the 1st, 3rd, 7th, 14th, 21st, and 28th days after deposition.The dentin adhesive applied to the ARM and giomer could not completely block the fluoride release; however, it significantly reduced its amount. The cumulative amount of fluoride release of the ARM after 28 days was higher than that of the giomer regardless of the application of dentin adhesive.

Effect of Photothermal Therapy with Indocyanine Green in Multispecies Biofilm / 대한소아치과학회지

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.

Micromorphological Analysis of Primary Second Molar withMolar-incisor Malformation : A Case Report / 대한소아치과학회지

Molar-incisor malformation (MIM) is characterized by malformation in the root with a normal crown. While MIM mostly occurs in the permanent first molar, it has also been reported in the maxillary central incisor and the primary second molar (PSM), but anatomical analysis of the primary teeth with MIM has not been studied to date. In this case report, a patient with MIM was reported, and an extracted PSM with MIM was analyzed with micro computed tomography (CT). A cervical constriction morphology of the cementoenamel junction (CEJ) can be observed in extracted PSM. In micro CT analysis, characteristics such a mineralized plate (cervical mineralized diaphragm) in the CEJ area, complex root canal morphologies, a calcified mass inside the pulp chamber, and constricted pulp chamber of crown portion were observed.

Streptococcus Mutans Biofilm Inhibition Effect of Indocyanine Green and Near Infrared Diode Laser / 대한소아치과학회지

The purpose of this study was to evaluate the effect of Indocyanine Green (ICG) and near-infrared (NIR) diode laser on Streptococcus mutans biofilms depending on ICG concentrations.S. mutans biofilms were formed on a Hydroxyapatite disk, and 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solutions dissolved in sterile distilled water and a NIR diode laser having a power of 300 mW and a wavelength of 808 nm were applied to the biofilms. The temperature changes of the biofilm surface according to the concentrations of the ICG solution were measured using a 1-channel thermocouple thermometer.Compared to the control group, in the groups with only the 3.0, 4.0, 5.0 mg/mL ICG solution application, and in the groups with the 1.0, 2.0, 3.0, 4.0, 5.0 mg/mL ICG solution application and light irradiation, a statistically significant decrease in the bacterial counts were observed.The temperature increase according to the concentration of the ICG solutions was 9.53℃, 10.43℃, 11.40℃, 12.10℃, 12.67℃, and 13.63℃ in ICG solutions of 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 mg/mL respectively.This study presents the potential for clinical application of ICG and NIR diode lasers as a new method for preventing dental caries.

Antimicrobial Effect of Photodynamic Therapy Using Plaque Disclosing Agent / 대한소아치과학회지

The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) using plaque disclosing agent, 10 - 20 mM erythrosine, as a photosensitizer.Multispecies cariogenic biofilms containing Streptococcus mutans , Lactobacillus casei and Candida albicans were formed on hydroxyapatite disc. 20 μM, 10 mM and 20 mM erythrosine were applied as a photosensitizer for 3 minutes, and then light-emitting diode (LED) irradiated for 24 seconds. Colony-forming unit (CFU) were measured and biofilms were observed using confocal laser scanning microscopy (CLSM). CFU were significantly decreased in the PDT groups using 10 - 20 mM erythrosine (10 mM, 20mM) and the results were also confirmed by CLSM.This study confirms the high antimicrobial effect of photodynamic therapy using plaque disclosing agent as a photosensitizer.

Surface Roughness and Microbial Adhesion After Finishing of Alkasite Restorative Material / 대한소아치과학회지

This study is aimed to evaluate and compare the surface roughness and microbial adhesion to alkasite restorative material (Cention N), resin-modified glass ionomer (RMGI), and composite resin. And to examine the correlation between bacterial adhesion and surface roughness by different finishing systems.Specimens were fabricated in disk shapes and divided into four groups by finishing methods (control, carbide bur, fine grit diamond bur, and white stone bur). Surface roughness was tested by atomic force microscope and surface observation was performed by scanning electron microscope. Colony forming units were measured after incubating Streptococcus mutans biofilm on specimens using CDC biofilm reactor.Cention N surface roughness was less than 0.2 μm after finishing procedure. Control specimens of resin and Cention N specimens were significantly (p = 0.01) rougher. Pearson correlation coefficient (PCC = 0.13) indicated a weak correlation between surface roughness and S. mutans adhesion to the specimens.Compared with resin specimens, RMGI and Cention N showed lower microbial adhesion. Surface roughness and bacterial adhesion were not significantly different, regardless of the finishing systems.

Autotransplantation of Premolars and Esthetic Rehabilitation in a Traumatized Teenage Patient with Challenging Oral Problems: A Case Report / 대한소아치과학회지

The loosely structured periodontal ligament and low mineralized bone surrounding erupting teeth provide minimal resistance to an extrusive force. The maxillary central incisors are the most frequently avulsed due to trauma. The prognosis of replanted teeth is affected by extra-alveolar period and conditions. Implant-supported restorations are contraindicated in adolescent patients with poor prognosis traumatized teeth. Autotransplantation of premolar to the anterior region provides a viable treatment alternative.This case report describes the autotransplantation of premolars and esthetic rehabilitation in a teenage patient with traumatized incisors, poor oral hygiene, and severe crowding. Comprehensive and long-term treatments were performed to improve complex and challenging oral problems.

Application of Teeth Whitening LED for Prevention of Dental Caries : Antimicrobial Photodynamic Therapy Approach / 대한소아치과학회지

The present study is aimed to assess the effect of antimicrobial photodynamic therapy (aPDT) on Streptococcus mutans biofilm through teeth whitening light emitting diode (LED).Planktonic and dynamic biofilm state cultures of S. mutans were used. Erythrosine 20 μM/L was used as the photosensitizer. Irradiation was performed by exposing cultures to clinic and homecare whitening LEDs for 15 minutes. The viability was measured through Colony Forming Unit counts and confocal laser scanning microscopy.aPDT using whitening LEDs and erythrosine significantly decreased the CFU count of S. mutans compared to that in the control group. Dynamic biofilm group showed more resistant features to aPDT compared with planktonic state. Clinic and homecare whitening LED device showed similar antimicrobial effect.The whitening LED, which could irradiate the entire oral arch, showed a significant photodynamic effect on cariogenic S. mutans biofilm. aPDT mediated by erythrosine and LEDs used for teeth whitening exhibited promising antimicrobial activity.

The Trends of Underweight in South Korean between 1998 and 2015

BACKGROUND: Underweight is associated with increased mortality, relative to the normal weight category. The importance of managing underweight patients has not yet been recognized seriously in South Korea, and little information is available on the prevalence of underweight and its associated risk factors. This study aims to investigate changes in the prevalence of underweight by gender and age and analyze its trend.METHODS: Data were obtained from individuals aged >20 years, from the Korean National Health and Nutrition Examination Survey between 1995 and 2015. The subjects of this study included 134,613 adults (male, 61,152; female, 73,461). The prevalence of underweight was determined as defined by the Asia-Pacific Perspective, and socioeconomic factors associated with a predisposition to underweight were analyzed using the chi-squared test and multiple logistic regression analysis.RESULTS: Among Korean adults, the age-adjusted prevalence of underweight (body mass index < 18.5 kg/m²) was 3.1% in men and 6.3% in women. Overall, a U-shaped relationship was established between the prevalence of underweight by gender and age. There was no significant difference in socioeconomic factors related to the prevalence of underweight in men and women in their twenties. The prevalence of underweight in women aged 20–59 years showed an increasing trend (P for trends < 0.05).CONCLUSION: In individuals aged 20–29 years, the prevalence of being underweight was higher in women than in men. Recently, there has been an increasing trend in the prevalence of underweight young women of reproductive age. This requires national public health attention.

Susceptibility of Mutans streptococci in the Planktonic and Biofilm State to Erythrosine / 대한소아치과학회지

The aim of this study was to investigate the susceptibility of Mutans streptococci in both planktonic and biofilm states to erythrosine.S. mutans was cultured in brain-heart infusion (BHI) broth. Erythrosine was diluted in BHI broth and prepared at a concentration range of 0.02 – 10000 µg/L. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured using the microdilution method. After forming biofilms on 96-well plates, the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were measured.S. mutans was susceptible to erythrosine in both planktonic and biofilm states. MIC and MBC values were both 19.5 µg/L for the planktonic state, while MBIC and MBEC values were 313 µg/L and 2500 µg/L, respectively, for the biofilm state.Erythrosine (19.5 µg/L) exhibited a bactericidal effect on S. mutans (killing 99.9%) in the planktonic state. For biofilms, erythrosine inhibited biofilm growth and eradicated 99.9% of biofilm bacteria at higher concentrations than MIC and MBC. These MBIC and MBEC concentrations are much lower than known noxious doses, and the MIC, MBC, and MBIC values were even lower than clinical concentrations.

Effect of Saliva Contamination Stage and Different Decontamination Procedures on Bonding Strength of Resin-Modified Glass Ionomer / 대한소아치과학회지

The purpose of this study was to compare the bond strength of resin-modified glass ionomer (RMGI) to dentin with saliva contamination at different stages and using different decontamination procedures.Extracted human permanent molars were embedded onto acrylic resin with the dentin surface exposed. Group I was a control group that was conditioned with polyacrylic acid (PAA). Groups II and III were contaminated with saliva before PAA conditioning and Groups IV, V, and VI were contaminated with saliva after PAA conditioning. After saliva contamination, Groups II and IV were dried, Groups III and V were rinsed and dried, and Group VI was additionally conditioned with PAA. After surface treatment, the dentin specimens were filled with RMGI.Group I showed significantly higher bond strength than the other groups. Group VI showed a significantly higher bond strength than the other saliva contaminated groups. However, there were no significant differences in the failure mode between the different groups.Saliva contamination impaired the bond strength of RMGI to dentin, regardless of when the saliva contamination occurred. Decontamination with washing and drying could not improve the shear bond strength of RMGIC. When saliva contamination occurred after PAA conditioning, additional PAA conditioning improved the shear bond strength.

Influence of Application Method on Shear Bond Strength and Microleakage of Newly Developed 8th Generation Adhesive in Primary Teeth / 대한소아치과학회지

The purpose of this study was to evaluate the effect of application time and phosphoric acid etching of 8th generation adhesives containing functional monomer on adhesive performance in primary teeth.80 extracted non-carious human primary teeth were selected and divided into 8 groups based on 3 factors: (1) adhesive: G-Premio bond and Single bond universal; (2) application time: shortened time and manufacture's instruction; (3) acid etching mode: self-etching and total-etching. Shear bond strength was measured using a universal testing machine, and fractured surface were observed under scanning electron microscope. Microleakage was evaluated by dye penetration depth.G-Premio bond were not significant different in shear bond strength and microleakage depending on application time of adhesive and acid etching mode. In Single bond universal, shear bond strength of short application time was significantly lower than that of long adhesive application time (p = 0.014). Clinically applicable shear bond strength values (> 17 MPa) were identified in all groups.These results suggested that G-Premio bond be used clinically for a short application time without phosphoric acid etching.

Effect of Nano-filled Protective Coating on Microhardness and Wear Resistance of Glass-ionomer Cements / 대한소아치과학회지

The purpose of this study was to investigate the effect of adding a protective coating on the microhardness and wear resistance of glass ionomer cements (GICs).Specimens were prepared from GIC and resin-modified GIC (RMGI), and divided into 3 groups based on surface protection: (1) no coating (NC), (2) Equia coat coating (EC), and (3) un-filled adhesive coating (AD). All specimens were then placed in distilled water for 24 h. Surface hardness (n = 10) was evaluated on a Vickers hardness testing machine. Wear resistance (n = 10) was evaluated after subjecting the specimen to thermocycling for 10,000 cycles using a chewing simulator. Data were analyzed using a one-way ANOVA and the Kruskal-Wallis test.Surface hardness was highest in the NC groups, followed by the EC and AD groups. The wear depth of GI + NC was significantly higher than that of all RMGI groups. EC did not significantly lower the wear depth compared to AD.Based on these results, it was concluded that although EC does not increase the surface microhardness of GIC, it can increase the wear resistance.

Psychiatric Symptoms and Clinical Diagnosis in High School Students Exposed to the Sewol Ferry Disaster

BACKGROUND: Two hundred and fifty 11th grade students and teachers from Danwon High School drowned, during a school trip, in the Sewol Ferry Disaster. The goal of this study was to investigate the experiences of the psychiatrists who volunteered and provided psychiatric services to the students at Danwon High School. METHODS: From the second day to the 138th day after the disaster, pro bono psychiatrists provided post-disaster interventions to the 10th and 12th-grade Danwon High School students who did not attend the trip. Officially, 167 psychiatrists conducted outreach in approximately 550 encounters. The study questionnaires were distributed retrospectively to psychiatric volunteers who conducted outreach at Danwon High School. We surveyed the pro bono psychiatrists about their experiences, including the students' chief complaints, psychiatric problems, clinical diagnoses, and psychiatrists' treatment recommendations. RESULTS: We reached 72 (43.1%) of the 167 volunteers, and they reported on 212 (38.6%) of the 550 encounters. The common chief complaints were mental health problems, companion problems, and family problems. The most frequent psychiatric symptoms were anxiety (76.89%), depressive mood (51.42%), and concentration difficulty (50.94%). The most frequent clinical diagnoses of the students were normal reaction (41.04%), acute stress disorder (24.53%), adjustment disorder (17.92%), anxiety disorders (9.43%), and posttraumatic stress disorder (6.60%). More than half of the students needed “additional counseling/therapy” (41.04%) or “referral to psychiatric treatment” (14.15%). CONCLUSION: During the acute aftermath of the Sewol Ferry Disaster, volunteer psychiatrists were able to provide services. These services included psychiatric assessments, crisis counseling, psychological first aid, and referrals for ongoing care. More than half of the students were perceived to have a psychiatric diagnosis, and a substantial proportion of students needed further treatment. Future research should focus on the short- and long-term effects of psychiatric interventions and the characterization of post-disaster mental health needs and service provision patterns.

Mental Health Interventions Provided by Volunteer Psychiatrists after the Sewol Ferry Disaster: April 16–November 30, 2014

OBJECTIVE: The aim of this study was to examine the experience of volunteer psychiatrists who provided mental health interventions to adolescents and teachers of Danwon High School from April 16, 2014, to November 30, 2014. METHODS: Data for this study were collected from 72 volunteer psychiatrists about their intervention experiences for 212 adolescents and 32 teachers during the eight months following the disaster. Developmental survey themes were identified, and coding was used to analyze the data. In addition, qualitative data analysis was performed using ATLAS.ti (version 8.2, 2018, ATLAS.ti GmbH). RESULTS: A volunteer prepared with appropriate mental health interventions may facilitate the emergency response to a disaster. Intervention services included psychological first aid, psychoeducation, screening, anxiety reduction techniques, and group therapy. CONCLUSION: In the acute aftermath of the Sewol Ferry disaster of April 16, 2014, volunteer psychiatrists were able to provide mental health interventions in a disaster response setting. The outcomes from this study have important policy and mental health system implications for volunteer psychiatrists. The results of this study constitute the basis of a better understanding of the essential mechanisms of crisis interventions after a disaster.