Shear Bond Strength of Different MDP-Containing Adhesive Systems on Enamel and Dentin from Primary Teeth.

OBJECTIVE: To compare the shear bond strength (SBS) after thermocycling of four universal adhesives applied in self-etch mode on dentin and etch-and-rinse mode on enamel. STUDY DESIGN: Flat 144 buccal or lingual dentin and enamel surfaces from 72 non-carious primary molars were prepared. Samples were segregated into 12 groups (n=12): Adper Single Bond 2 etch-and-rinse (SB_T) and Clearfil SE Bond self-etch (SE_S) applied to enamel and dentin served as controls. Scotch Bond Universal Adhesive (SBU), Clearfil S3 Bond Universal Adhesive (SEU), Tetric N-Bond Universal Adhesive (TEN), and All Bond Universal (BIS) were applied in etch-and-rinse mode to enamel and in self-etch mode to dentin. They were thermocycled for 5000 cycles. SBS testing and the evaluation of fracture mode were performed. RESULTS: SB_T showed statistically higher SBS than other adhesive groups using etch-and-rinse mode on enamel. SE_S and BIS had statistically higher SBS than other adhesive groups using self-etch mode on dentin. Mixed failure was the most common failure mode in each group. CONCLUSION: The universal adhesives did not show higher SBS than SB_T when using etch-and-rinse on enamel. All universal adhesives showed higher SBS than SB_T and had SBS similar to SE_S, except SBU when using self-etch mode on dentin.

Clinical Considerations for Dental Management of Children with Molar-Root Incisor Malformations.

Molar root-incisor malformation (MRIM) or molar-incisor malformation (MIM) is a new type of dental anomaly characterized by dysplastic roots of permanent first molars, occasionally second primary molars, and the crowns of maxillary central incisors. MRIM involving permanent first molars and second primary molars is characterized by normal crowns with short, thin, and narrow roots, whereas MRIM involving permanent maxillary central incisors exhibits constrictions of the crown in the cervical area. In the first case, we extracted the affected first permanent molars at the optimal timing to minimize space deficiencies and induce space closure. In addition, composite resin restorations were performed on the anterior central incisors. In the second case, a mandibular lingual arch was used to stabilize the affected teeth in order to mitigate discomfort by reducing rotational biting forces.

Fabrication of bi-layer scaffold of keratin nanofiber and gelatin-methacrylate hydrogel: Implications for skin graft.

Bi-layer scaffold composed of human hair keratin/chitosan nanofiber mat and gelatin methacrylate (GelMA) hydrogel was fabricated by using electrospinning and photopolymerization techniques. To prepare the nanofiber layer, the blend solution of human hair keratin and chitosan (mixture ratio: 5/5) was electrospun using formic acid as a solvent in the presence of poly(ethylene glycol), followed by cross-linking with glutaraldehyde. The tensile strength of the human hair keratin/chitosan nanofiber mat was much higher than that of pure human hair keratin nanofiber mat. Meanwhile, the blend nanofiber mat was relatively more compatible with HaCaT cell proliferation and keratinocyte differentiation than the pure chitosan nanofiber mat. The bi-layer scaffold was prepared by photopolymerization of GelMA under the cross-linked nanofiber mat. To evaluate the feasibility as a skin graft, human fibroblast was encapsulated in the hydrogel layer and HaCaT cells were cultured on the nanofiber layer and they were co-cultured for 10days. As a result, the encapsulated fibroblasts proliferated in the hydrogel matrix and HaCaT cells formed a cell layer on the top of scaffold, mimicking dermis and epidermis of skin tissue.

[The relationship between dental graduate students' MBTI types and academic achievement in problem-based learning].

PURPOSE: The study aimed to determine the personality types of the graduate students in Seoul National University School of Dentistry (SNU SD) and analyze the specific personal types that were linked to their performance in problem-based learning (PBL). METHODS: A total of 263 graduate students in SNU SD from 2011 to 2013, participated in PBL and completed the Myers-Briggs Type Indicator (MBTI) GS form, which was analyzed statistically to determine whether their MBTI personality types were independent of their PBL performance. In particular, MBTI types were regressed on evaluation subcategories, including tutor evaluation and oral test. RESULTS: ESTJ (20.9%) and ISTJ (18.6%) were the most common MBTI personality types in dental graduate students. Compared with males, female students performed significantly better on the PBL. Judging was the most notable type in PBL performance, with its J-P index being statistically significant. CONCLUSION: PBL is implemented, based on the perspective of student-centered education. Accordingly, the types of personality that usually matriculate in dental school should be monitored, and a student-centered approach to dental education should be adopted.

The secondary prophylactic efficacy of beta-blocker after endoscopic gastric variceal obturation for first acute episode of gastric variceal bleeding.

BACKGROUND/AIMS: The most appropriate treatment for acute gastric variceal bleeding (GVB) is currently endoscopic gastric variceal obturation (GVO) using Histoacryl®. However, the secondary prophylactic efficacy of beta-blocker (BB) after GVO for the first acute episode of GVB has not yet been established. The secondary prophylactic efficacy of BB after GVO for the first acute episode of GVB was evaluated in this study. METHODS: Ninety-three patients at Soonchunhyang University Hospital with acute GVB who received GVO using Histoacryl® were enrolled between June 2001 and March 2010. Among these, 42 patients underwent GVO alone (GVO group) and 51 patients underwent GVO with adjuvant BB therapy (GVO+BB group). This study was intended for patients in whom a desired heart rate was reached. The rates of rebleeding-free survival and overall survival were calculated for the two study groups using Kaplan-Meyer analysis and Cox's proportional-hazards model. RESULTS: The follow-up period after the initial eradication of gastric varices was 18.14±25.22 months (mean±SD). During the follow-up period, rebleeding occurred in 10 (23.8%) and 21 (41.2%) GVO and GVO+BB patients, respectively, and 39 patients died [23 (54.8%) in the GVO group and 16 (31.4%) in the GVO+BB group]. The mean rebleeding-free survival time did not differ significantly between the GVO and GVO+BB groups (65.40 and 37.40 months, respectively; P=0.774), whereas the mean overall survival time did differ (52.54 and 72.65 months, respectively; P=0.036). CONCLUSIONS: Adjuvant BB therapy after GVO using Histoacryl® for the first acute episode of GVB could decrease the mortality rate relative to GVO alone. However, adjuvant BB therapy afforded no benefit for the secondary prevention of rebleeding in GV.