Vesna Miletic 1,2 , Ario Santini 1 1  The University of Edinburgh, Edinburgh Postgraduate Dental Institute,  United Kingdo...
<ul><li>Studies investigating the degree of conversion (DC) of adhesives - samples prepared in a variety of ways </li></ul...
<ul><li>To study the effect of preparation and storage conditions on the DC of  </li></ul><ul><li>two adhesive systems usi...
<ul><li>Sample preparation: </li></ul><ul><ul><li>Etch-and-rinse (Excite,  Ivoclar Vivadent )  </li></ul></ul><ul><ul><li>...
<ul><li>Sample preparation: </li></ul><ul><ul><li>Etch-and-rinse (Excite,  Ivoclar Vivadent )  </li></ul></ul><ul><ul><li>...
<ul><li>Micro-Raman spectroscopy  </li></ul><ul><li>(5 min post-curing, 3 random spectra per sample, top surface) </li></u...
<ul><li>Storage conditions: </li></ul><ul><ul><li>Adhesives: Excite and Clearfil3S (n=5) </li></ul></ul><ul><ul><li>Glass ...
<ul><li>Storage conditions (24 hours) </li></ul><ul><ul><li>Group I (22±2ºC and 45±3% humidity) -  </li></ul></ul><ul><ul>...
<ul><li>Statistics </li></ul><ul><ul><li>ANOVA and repeated measures ANOVA </li></ul></ul><ul><ul><li>t test </li></ul></u...
RESULTS
<ul><ul><li>Sample storage  -   Excite -  Glass slides  </li></ul></ul><ul><ul><li>Groups: high humidity, distilled water ...
<ul><ul><li>Sample storage  -   Clearfil 3S -  Glass slides </li></ul></ul>Group 1    Group 2 <ul><ul><li>Group 1: p<0.001...
<ul><ul><li>Sample storage  -   Excite -  Dentine discs </li></ul></ul>Group 1  Group 2  Group 3  Group 4 <ul><ul><li>Befo...
<ul><ul><li>Sample storage  -   Clearfil 3S -  Dentine discs </li></ul></ul><ul><ul><li>Repeated measures ANOVA  </li></ul...
<ul><li>Sample preparation and storage significantly affected the DC of the etch-and-rinse and self-etch adhesive </li></u...
<ul><li>Variables such as oxygen inhibition and elution should be eliminated as they do not represent the DC of the adhesi...
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IADR 2010

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IADR 2010

  1. 1. Vesna Miletic 1,2 , Ario Santini 1 1 The University of Edinburgh, Edinburgh Postgraduate Dental Institute, United Kingdom 2 University of Belgrade, School of Dentistry, Serbia Effect of preparation and storage on adhesive monomer conversion
  2. 2. <ul><li>Studies investigating the degree of conversion (DC) of adhesives - samples prepared in a variety of ways </li></ul><ul><li>Substrates such as potassium-bromide pellet/crystal, acetate strips, glass slides or dentine discs </li></ul><ul><li>Light curing with or without the use of a Mylar strip covering </li></ul><ul><li>Variations in storage parameters such as time, temperature, humidity and media </li></ul>INTRODUCTION
  3. 3. <ul><li>To study the effect of preparation and storage conditions on the DC of </li></ul><ul><li>two adhesive systems using </li></ul><ul><li>micro-Raman spectroscopy. </li></ul>OBJECTIVE
  4. 4. <ul><li>Sample preparation: </li></ul><ul><ul><li>Etch-and-rinse (Excite, Ivoclar Vivadent ) </li></ul></ul><ul><ul><li>and self-etch adhesive (Clearfil 3S, Kuraray ) </li></ul></ul><ul><ul><li>n=5 </li></ul></ul><ul><ul><li>Glass slides vs. Dentine discs </li></ul></ul><ul><ul><li>Mylar strip covering vs. No Mylar strip covering </li></ul></ul><ul><ul><li>LED light (bluephase, Ivoclar Vivadent ) intensity 650 mW/cm 2 , 10 s curing time, 1 mm distance </li></ul></ul>MATERIALS AND METHODS
  5. 5. <ul><li>Sample preparation: </li></ul><ul><ul><li>Etch-and-rinse (Excite, Ivoclar Vivadent ) </li></ul></ul><ul><ul><li>and self-etch adhesive (Clearfil 3S, Kuraray ) </li></ul></ul><ul><ul><li>n=5 </li></ul></ul><ul><ul><li>Glass slides vs. Dentine discs </li></ul></ul><ul><ul><li>Mylar strip covering vs. No Mylar strip covering </li></ul></ul><ul><ul><li>LED light (bluephase, Ivoclar Vivadent ) intensity 650 mW/cm 2 , 10 s curing time, 1 mm distance </li></ul></ul>MATERIALS AND METHODS
  6. 6. <ul><li>Micro-Raman spectroscopy </li></ul><ul><li>(5 min post-curing, 3 random spectra per sample, top surface) </li></ul>MATERIALS AND METHODS DC=[1-Rcured / Runcured] x 100
  7. 7. <ul><li>Storage conditions: </li></ul><ul><ul><li>Adhesives: Excite and Clearfil3S (n=5) </li></ul></ul><ul><ul><li>Glass slides / Dentine discs </li></ul></ul><ul><ul><li>Mylar strip covering </li></ul></ul><ul><ul><li>LED light (bluephase) intensity 650 mW/cm 2 , 10 s curing time, 1 mm distance </li></ul></ul><ul><ul><li>Micro-Raman spectroscopy 5 min post-curing and after storage </li></ul></ul>MATERIALS AND METHODS
  8. 8. <ul><li>Storage conditions (24 hours) </li></ul><ul><ul><li>Group I (22±2ºC and 45±3% humidity) - </li></ul></ul><ul><ul><li>light proof container, laboratory bench </li></ul></ul><ul><ul><li>Group II (37±1ºC and 90±2% humidity) - </li></ul></ul><ul><ul><li>light proof container with side openings, water bath with punched aluminum foil cover </li></ul></ul><ul><ul><li>Group III (distilled water at 37±1ºC) - </li></ul></ul><ul><ul><li>glass vial, 1 ml distilled water, covered water bath </li></ul></ul><ul><ul><li>Group IV (artificial saliva at 37±1ºC) - </li></ul></ul><ul><ul><li> glass vial, 1 ml artificial saliva, covered water bath </li></ul></ul>MATERIALS AND METHODS
  9. 9. <ul><li>Statistics </li></ul><ul><ul><li>ANOVA and repeated measures ANOVA </li></ul></ul><ul><ul><li>t test </li></ul></ul><ul><ul><li>significance level α =0.05 </li></ul></ul>MATERIALS AND METHODS
  10. 10. RESULTS
  11. 11. <ul><ul><li>Sample storage - Excite - Glass slides </li></ul></ul><ul><ul><li>Groups: high humidity, distilled water and artificial saliva => sample deformation, impossible to obtain micro-Raman spectra from the top surface </li></ul></ul><ul><ul><li>Group stored at 22±2ºC and 45±3% humidity </li></ul></ul><ul><ul><li>Before: DC=70.8%(1.7%) </li></ul></ul><ul><ul><li>After: DC=73.6%(1.8%) </li></ul></ul><ul><ul><li>[paired t-test, p<0.05] </li></ul></ul>RESULTS
  12. 12. <ul><ul><li>Sample storage - Clearfil 3S - Glass slides </li></ul></ul>Group 1 Group 2 <ul><ul><li>Group 1: p<0.001 </li></ul></ul><ul><ul><li>Group 2: p<0.001 </li></ul></ul><ul><ul><li>Group 1 vs. Group 2 (before): p=0.208 </li></ul></ul><ul><ul><li>Group 1 vs. Group 2 (after): p<0.001 </li></ul></ul><ul><ul><li>[t-test] </li></ul></ul>RESULTS
  13. 13. <ul><ul><li>Sample storage - Excite - Dentine discs </li></ul></ul>Group 1 Group 2 Group 3 Group 4 <ul><ul><li>Before vs. After </li></ul></ul><ul><ul><li>Group 1: p=0.002 </li></ul></ul><ul><ul><li>Group 2: p=0.007 </li></ul></ul><ul><ul><li>Group 3: p<0.001 </li></ul></ul><ul><ul><li>Group 4: p<0.001 </li></ul></ul><ul><ul><li>[repeated measures ANOVA and paired t test] </li></ul></ul>RESULTS
  14. 14. <ul><ul><li>Sample storage - Clearfil 3S - Dentine discs </li></ul></ul><ul><ul><li>Repeated measures ANOVA </li></ul></ul><ul><ul><li>Factor “Medium”: p=0.507 </li></ul></ul><ul><ul><li>Factor “Time”: p<0.001 </li></ul></ul><ul><ul><li>Interaction “Medium” x “Time”: p=0.190 </li></ul></ul>RESULTS
  15. 15. <ul><li>Sample preparation and storage significantly affected the DC of the etch-and-rinse and self-etch adhesive </li></ul><ul><li>Differences in the effect of both preparation and storage were observed for the two adhesives </li></ul><ul><li>Oxygen inhibition on the adhesive surface was significantly reduced using Mylar strips </li></ul><ul><li>“ Dark” cure during storage increased the initial DC due to consumption of C=C double bonds </li></ul><ul><li>Compared to storage in air, liquid media further increased the DC, most likely due to elution of monomers </li></ul>CONCLUSIONS
  16. 16. <ul><li>Variables such as oxygen inhibition and elution should be eliminated as they do not represent the DC of the adhesive polymer </li></ul><ul><li>Non-dental models may be appropriate for comparing e.g. effects of curing lights/curing times on conversion but not for material comparison since the results may not be clinically relevant </li></ul>CONCLUSIONS

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