No abstract

To measure the repair shear bond strength (SBS) of an aged bulk-fill composite after different mechanical (diamond bur vs sandblasting) and chemical (universal adhesive with or without a previous silanization) surface treatments. Materials and Methods: Bulk-fill composite (Filtek One Bulk Fill, 3M ESPE) was used to construct seventy-two specimens aged through 10,000 thermal cycles. The specimens were allocated into two groups (n = 36 each) according to the mechanical roughening: Db, treated with a diamond bur, and Sb, treated by sandblasting. Each group was further subdivided into three subgroups (n = 12 each) according to the chemical conditioning: Db-only and Sb-only, unconditioned specimens; Db-U and Sb-U, specimens were conditioned with silane-containing universal adhesive (Scotchbond Universal adhesive, 3M ESPE); and Db-S-U and Sb-S-U, specimens were conditioned with a silane agent (Prosil, FGM) before employing the universal adhesive. The same composite material was used for repair. An additional reference group was constructed to measure the cohesive strengths of the bulk-fill composite. SBS testing was performed using a universal testing machine at a crosshead speed of 1 mm/min, and the failure modes were evaluated by stereomicroscope. The surface topography of resin composite after roughening was assessed by scanning electron microscopy. SBS data were statistically analyzed by ANOVA, Tukey's test and independent t-test. Results: The significantly highest SBS was recorded in the reference group (P ≤ 0.05). Sb-only obtained significantly higher SBS than Db-only (P < 0.001). No significant difference in SBS was noted between Db-U and Sb-U or Db-S-U and Sb-S-U. Likewise, no significant difference was observed between the subgroups treated with or without silane (P > 0.05). Conclusion:The sandblasted specimens demonstrated a higher repair SBS than the diamond bur-treated specimens. The use of an additional silanizing step before applying silane-containing universal adhesive did not enhance the SBS of the repaired composite.

The 21st-century learning paradigm emphasises the need for students to develop thinking skills, particularly higher-order thinking skills (HOTS). In this regard, teachers play a crucial role in facilitating the application of HOTS in the classroom. Thus, this paper aims to develop a measuring instrument to assess teachers' practice of HOTS in secondary schools. The questionnaire consists of 30 items and three dimensions: facilitating HOTS, Socratic questioning, and applying the i-THINK map. Three experts validated the instrument for face and content validity. Data was collected in Terengganu from a total of 126 respondents and analysed using the Statistical Package for Social Sciences (SPSS) version 25. The analyses included exploratory factor analysis (EFA), Bartlett's sphericity test, Kaiser-Meyer-Olkin (KMO) sampling adequacy test, and Cronbach's alpha reliability test. The findings revealed a three-dimensional model with 28 items. In addition, Bartlett's sphericity tests for all dimensions were significant (P<0.05), the sampling adequacy revealed a favourable result (KMO>0.6), and the values of Cronbach's alpha exceeded the threshold value of 0.7. Overall, the results indicate that the instrument has high validity and reliability in measuring HOTS teaching practice. Furthermore, this study highlights the importance of teachers' roles as facilitators, effective questioning techniques, and thinking aids in holistic teaching.

No abstract

No abstract