## Appendix A Study Questionnaire  
Part A. Demographic Characteristics  
Q1. What is your gender? (single choice)  
- Q1.1. Male  
- Q1.2. Female  
- Q1.3. Other  
Q2. What is your age? (single choice)  
- Q2.1. 24-35  
- Q2.2. 36-45  
- Q2.3. 46-55  
- Q2.4. 56-65  
- Q2.5. 66-75  
Q3. What is your educational background? (multiple choice)  
- Q3.1. Graduate of a dental school in Greece  
- Q3.2. Graduate of a dental school abroad  
- Q3.3. Master's degree in dentistry  
- Q3.4. Master's degree in a related field  
- Q3.5. Doctorate (PhD) in dentistry  
- Q3.6. Doctorate (PhD) in a related field  
- Q3.7. Additional degree in another discipline outside of dentistry  
Q4. What type of professional setting best describes your work? (multiple choice)  
- Q4.1. Private dental office (own practice)  
- Q4.2. Work at a colleague's dental office  
- Q4.3. Work in a group practice with more than 3 dentists  
- Q4.4. Work in a university clinic  
- Q4.5. Work in a public institution  
- Q4.6. Other  
Q5. How many years of clinical experience do you have as a dentist? (single choice)  
- Q5.1. 0-5* Q5.2. 6-10
* Q5.3. 11-15
* Q5.4. 16-20
* Q5.5. 21-25
* Q5.6. 26-30
* Q5.7. More than 31  
Part B. General Questions Regarding Restorative Materials  
Q6. How often do you purchase resin-based restorative materials? (single choice)  
* Q6.1. Once per year
* Q6.2. Twice per year
* Q6.3. More than twice per year
* Q6.4. I stock up when there are special offers
* Q6.5. Whenever the previous stock runs out
* Q6.6. I do not purchase materials myself; someone else handles procurement
* Q6.7. I do not purchase resin-based materials because I specialize in an area that does not use them  
Q7. On average, how many resin composite restorations do you or your team perform per week? (single choice)  
* Q7.1. Fewer than 20
* Q7.2. 20-50
* Q7.3. More than 50
* Q7.4. I don't know/prefer not to answer
* Q7.5. Other:  
Q8. How well do you know the following aspects of the main resin-based material you use in your practice? (Rate on a scale: 1 = Not at all, 2 = Slightly, 3 = Moderately, 4 = Well, 5 = Perfectly)  
* Q8.1. Its composition
* Q8.2. Its biocompatibility
* Q8.3. Its potential adverse effects
* Q8.4. Its lifespan
* Q8.5. Its application method
* Q8.6. Its type (hybrid, nanofilled, etc.) Q9. How has your approach to resin-based restorative materials changed after the COVID-19 pandemic? (multiple choice)  
* Q9.1. Increased orders of resin-based materials
* Q9.2. Decreased orders of resin-based materials
* Q9.3. Greater interest in materials with easy and fast workflows
* Q9.4. Less interest in materials with easy and fast workflows
* Q9.5. More interest in trying new materials
* Q9.6. Less interest in trying new materials
* Q9.7. No significant change in preferences
* Q9.8. I don't know/prefer not to answer
* Q9.9. Other:  
Q10. What criteria do you consider when selecting resin-based materials for anterior restorations? (multiple choice)  
* Q10.1. Desired anatomical features
* Q10.2. Available interdental space
* Q10.3. Shade of adjacent teeth Q10.4. Translucency and opacity of adjacent teeth  
- Q10.5. No specific criteria; I use whatever is in stock  
- Q10.6. Use only specialized anterior resins  
- Q10.7. I don't know/ prefer not to answer  
- Q10.8. Other:  
Q11. What criteria do you consider when selecting resin-based materials for posterior restorations? (multiple choice)  
- Q11.1. Desired anatomical features  
- Q11.2. Available interdental space  
- Q11.3. Shade of adjacent teeth  
- Q11.4. No specific criteria; I use whatever is in stock  
- Q11.5. I don't know/ prefer not to answer  
- Q11.6. Other:  
Q12. What is your material of choice for extensive direct posterior aesthetic restorations? (multiple choice)  
- Q12.1. Amalgam  
- Q12.2. High-viscosity (packable) composite resin  
- Q12.3. Flowable composite resin  
- Q12.4. Bulk-fill resin composite  
- Q12.5. Glass ionomer cement  
- Q12.6. Other:  
Part C. Questions Related to ISO Standards of Resin-Based Restorative Materials  
Q13.