2016, Vol.43, No.4

Journal of the Korean academy of pediatric dentistry 2023 KCI Impact Factor : 0.48

pISSN : 1226-8496 / eISSN : 2288-3819
https://journal.kci.go.kr/jkapd

The purpose of this study was to evaluate shear bond strength and microleakage of a new self-etch fissure sealant containing S-PRG filler (BeautiSealant). Fourty-five premolars were randomly divided into three groups: SEPBS group (Self-etching primer + BeautiSealant), AEBS group (Phosphoric acid etching + BeautiSealant), AECP group (Phosphoric acid etching + ClinproTM sealant). For the shear bond strength test, microcylinders of fissure sealant were bonded to prepared buccal surfaces of teeth and shear bond strengths were measured by a universal testing machine. For the microleakage test, sealants were applicated on each occlusal fissure of teeth. All teeth surface were coated with finger nail varnish, with the exception of a 1.0 mm window around the sealant margins. The teeth were immersed in 2% methylene blue solution for 24 hours and then rinsed in water. The teeth were then embedded in resin and cut buccolingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage. SEPBS group demonstrated lower bond strength in comparison with that of AEBS and AECP groups (p < 0.05). However, no significant differences were observed between AEBS and AECP groups. There was no statistically significant difference in degree of microleakage among three groups.

To evaluate the oral health status and to assess the resultant dental treatment needs in adolescents, 2,062 adolescents aged 14-17 years attending middle and high schools in Yangsan were surveyed by clinical examination and questionnaires. The obtained results were as follows. In the dental caries examination based on WHO criteria, the treatment needs of 66.7% of the subjects were determined. Assessment of dental erosion by the VEDE system indicated the treatment needs in 27.8% of the subjects, while MIH examination based on EAPD criteria indicated the treatment needs in 14.7%. Assessment of malocclusion using the occlusal index showed good occlusion in 67.8%, no need for treatment in 19.7%, slight need for treatment in 6.8%, definite need for treatment in 4.5%, and worst occlusion in 1.1% of the subjects, showing 12.5% of average treatment need. The prevalence and treatment need for periodontal disease was found to be 71.2% by CPITN assessments. The assessment of temporomandibular disorders by Helkimo’s anamnestic index showed no symptoms in 67.1%, mild symptoms in 13.4%, and severe symptoms in 19.5% of the examinees. The overall treatment need of TMD was 20.6%. Periodontal diseases were ranked the highest in treatment need, followed by dental caries, dental erosion, MIH, TMD, and malocclusion in order. The results of this study indicated the overall status of adolescents’oral health and dental treatment needs. These might hopefully provide fundamental data and contribute to establishing promotional projects for adolescent oral health in Korea.

Composites are the most useful restorative material. However, composites have some disadvantages such as polymerization shrinkage, long working time, and susceptibility to water and contamination, which are stood out more especially when treating children. To solve these problems, bulk-fill composites have been developed. The aim of this study is to compare mechanical properties of bulk-fill and conventional composites. Bulk-fill composites (SureFil SDR flow (SDR), Tetric N-Ceram bulk fill (TBF)) and conventional composites (Filtek Z-350 (Z-350), Unifil Flow (UF), Unifil Loflo Plus (UL)) were used. The Vickers hardness tester was used to measure the microhardness of materials, and Fourier transform infrared spectroscopy was used to measure the degree of conversion. Polymerization shrinkage was measured by using a linometer. Flexural and compressive properties were measured by using the universal testing machine. Data were statistically analyzed by ANOVA and Scheffe’s post hoc test. The level of significance was set to p < 0.05. Most conventional composites showed higher microhardness than bulk-fill composites. However, bulk-fill composites showed a higher top/bottom microhardness ratio than conventional composites. Bulk-fill composites showed a higher top/bottom degree of conversion ratio than conventional composites. The polymerization shrinkage was highest in UL and lowest in Z-350. The polymerization shrinkage of flowable composites was higher than that of non flowable composites. The compressive properties were highest in Z-350 and lowest in SDR and UL. In terms of flexural properties, Z-350 was the highest. However, none of the bulk-fill composites exhibited mechanical properties as good as those of conventional composites. Nonetheless, the ratio of microhardness and degree of conversion, which are important properties of bulk filling, were higher in bulk-fill composites. Therefore, the bulk-fill composites might be considered suitable restorative materials in pediatric dentistry.