Wow, what a presentation, Dr.Jojo. Very useful, The best thing about your presentation is the simplicity with which you explain even complicated things. Please continue the work!
Thank you for the presentation. I am close to finishing a PhD and I'm working on dental composites for structural applications. One part is moulding large dimension flexural test pieces of 8 mm thickness, and the same dimension pieces but in 2 layers of 4 mm each. All pieces cured from the top surface only, with Melinex sheet in contact with the composite and the curing light. I don't believe I have an OIL on the first layer because of the Melinex and the fact that I wipe and clean off the surface prior to adding the upper layer. I've found one of my formulations delaminates quite easily whereas the other has excellent properties. In fact, the modulus increases substantially when layered as compared to curing as a single bulk layer with only a small decrease in flexural strength. When they fracture, you can see the layers aren't directly bonded because the first layer is very glassy due to the contact with the Melinex. I wonder if you have any idea what may be happening? I fill the mould, put on a sheet of Melinex, cure the composite using my own technique (LCU in direct contact with Melinex, discrete cures similar to ISO 4049), chip away overflow and place a second mould on top of the original mould. Then repeat the process. I then clean up (acetone), and sandpaper the bars prior to testing. They are in deionised water before testing as well. Thank you
Glycerine layer is added on top of the last layer of cured resin or before curing the last layer itself, glycerine application is needed?...thank u for presenting the wonderful topic
That's as usual superb explanation. Thank you Sir for sharing. Sir one question, after placing the final layer of composite, do we cure it straightway for 10 or more seconds and then apply glycerin and cure again or we apply glycerin and then cure it completely? One more question sir, is the glycerin available in the market suitable for this or there is some specialized glycerin l available for this? Thank you Sir.
Very good Q Dr. Parvathy. Reports on how this OIL affects the bond strength have been inconsistent. Studies had shown that even in the absence of O2, tr is good bond bw the 1st n 2nd layer. When it comes to repair, let me put it this way. After light cure the degree of conversion will be max 60-70%. So logically we can assume that tr is some free radicle remaining at least for 1-2 days. Hence, if ur repairing the composite within 2 days, the FR remaining will facilitate repair even in the absence of OIL. However, if its beyond 2 days, i highly recommend sandblasting n application of silane coupling agent b4 we initiate repair
Sir very useful vdo. I had some cases where deep caries were filled with composites without using GIC as in sandwich techniques and due to this over a period of time of say as low as 1 month patient had severe pain and when that patient xame to us we had to struggle removing composite fron the chamber . Please sir guide us on these cases .
Greeting from Malaysia. Thank you so much for the useful lecture !!
Very useful video doctor.
Wow, what a presentation, Dr.Jojo. Very useful, The best thing about your presentation is the simplicity with which you explain even complicated things. Please continue the work!
❤️
Thankyou sir for the information....itz a privilage to hear it from the best teacher known to me.....
It's my pleasure
Excellent presentation
Thank you for the presentation.
I am close to finishing a PhD and I'm working on dental composites for structural applications. One part is moulding large dimension flexural test pieces of 8 mm thickness, and the same dimension pieces but in 2 layers of 4 mm each. All pieces cured from the top surface only, with Melinex sheet in contact with the composite and the curing light. I don't believe I have an OIL on the first layer because of the Melinex and the fact that I wipe and clean off the surface prior to adding the upper layer.
I've found one of my formulations delaminates quite easily whereas the other has excellent properties. In fact, the modulus increases substantially when layered as compared to curing as a single bulk layer with only a small decrease in flexural strength. When they fracture, you can see the layers aren't directly bonded because the first layer is very glassy due to the contact with the Melinex.
I wonder if you have any idea what may be happening?
I fill the mould, put on a sheet of Melinex, cure the composite using my own technique (LCU in direct contact with Melinex, discrete cures similar to ISO 4049), chip away overflow and place a second mould on top of the original mould. Then repeat the process. I then clean up (acetone), and sandpaper the bars prior to testing. They are in deionised water before testing as well.
Thank you
Thanks. Good input
Very informative sir and well explained
❤️
Great presentation sir. Thank you
❤️
Very informative lecture.. Thank you sir.
Most welcome
Thanks for precious information 🙏
Very informative, Sir. Thank you.
So nice of you
Thank u so much sir for making this video.plz make a video regarding different generation of bonding agents with details.
Informative Sir
Thank you
Welcome
Thank you sir, for this presentation..
Welcome dear babitha!
great sir...really informative
So nice of you
Great presentation sir😍 expecting more from u...😊
Keep watching
Awesome
Thanks
Great....always good to hear u
Thanks
Glycerine layer is added on top of the last layer of cured resin or before curing the last layer itself, glycerine application is needed?...thank u for presenting the wonderful topic
Preferably after initial curing, cure once more through glycerin
That's as usual superb explanation. Thank you Sir for sharing. Sir one question, after placing the final layer of composite, do we cure it straightway for 10 or more seconds and then apply glycerin and cure again or we apply glycerin and then cure it completely? One more question sir, is the glycerin available in the market suitable for this or there is some specialized glycerin l available for this? Thank you Sir.
It’s available from ivoclar. Or you can buy for the market
@@jojokottoor5103 thank you Sir for your response.
Very Informative ...
Thank you Sir !!!
Expecting more videos...
Thanks Thahseen..
Keep watching
as usual very informative sir,your take on whether oxygen inhibiting layer is required in repair of composites or not?
Very good Q Dr. Parvathy. Reports on how this OIL affects the bond strength have been inconsistent. Studies had shown that even in the absence of O2, tr is good bond bw the 1st n 2nd layer.
When it comes to repair, let me put it this way. After light cure the degree of conversion will be max 60-70%. So logically we can assume that tr is some free radicle remaining at least for 1-2 days. Hence, if ur repairing the composite within 2 days, the FR remaining will facilitate repair even in the absence of OIL. However, if its beyond 2 days, i highly recommend sandblasting n application of silane coupling agent b4 we initiate repair
@@jojokottoor5103 ok sir ,thank you sir
👏👏👏
Thanks dear Abi
Sir very useful vdo. I had some cases where deep caries were filled with composites without using GIC as in sandwich techniques and due to this over a period of time of say as low as 1 month patient had severe pain and when that patient xame to us we had to struggle removing composite fron the chamber . Please sir guide us on these cases .
By wetting the composite it’s easy to differentiate from dentine. You need to use some magnification
Thank you dr. Great presentation. Btw, in the 1st slides, the word free radical is written as Free Radicle.
#SpellingNazi 🙏
Thanks..Yes, that's correct.. Apologies
Respcted sir, in case of immediate dentine sealing followed by impression making, how do we remove the OIL?
Use glycerin & airlock it
Can bonding agent over the top of composite during final curing behave as a barrier to minimize the oxygen inhibition layer?
Nope. It still will creat an OIL
Any special glycerine is available sir or the normal glycerine
Normal one is fine
Can we use vaseline for OIL removal ?
Yes. But later we find it difficult to remove the Vaseline 😉
Very informative sir. Thank You
Glad it was helpful!