Another E-max Question

[PGguy]

Here's another one for everybody,


What do people do about the trans spot left from the sprue? I try to sprue on the lingual if possible to hide it, but if the only place is facial and your using stain technique, I find this a pain in the butt!!

Thanks,
PGguy

[Travis]

Your getting a visible spot were the sprue was with no cutback? That sux, do you have to grind it out and add enamel?

[ChrisR]

I had the same problem with LT and HT ingots. After inquiring with my trusty Ivoclar rep he informed me that this "HALO" is comming from incorrect spruing. As you said about spruing on the lingual to hide it, I was doing the same. I was trying to cheat a little by sticking it on a axial wall when it should be sprued on the incisal edge. After adjusting the sprue location I have not had 1 issue with "HALO'S" or spots.

[sixonice]

Originally Posted by PGguy

Here's another one for everybody,


What do people do about the trans spot left from the sprue? I try to sprue on the lingual if possible to hide it, but if the only place is facial and your using stain technique, I find this a pain in the butt!!

Thanks,
PGguy

As Chris stated above, to keep it really simple, you want to always sprue off the incisal edge. For the super scientific explanation read on:

This optical phenomenon is a result of the flow characteristics of the material. The cylindrical shape of the litihium disilicate crystals promotes an alignment of the crystal structures in the direction of flow. This is kind of like logs floating down a river. The logs will always float end to end and never side to side.

This crystal alignment refracts light in a specific pattern which gives the material a brighter look when viewed laterally (more light refraction) than when viewed from the end (more light penetration). This is not a problem when spruing is accomplished from the incisal edge as detailed in their instructions for use because all the crystals are aligned along the axial surfaces. However, when sprued from the facial, the crystals will remain aligned with the sprue for a distance into the axial wall of the restoration before changing direction to align with the axial surfaces. This creates an optical illusion that there is a difference in the material at the sprue attachment site. This phenomenon will be more pronounced with thick restorations and less pronounced in thin walls where the directional change of the lithium dislicate crystals occurs almost immediately upon the material entering the wall of the restoration.

[PGguy]

Originally Posted by sixonice

As Chris stated above, to keep it really simple, you want to always sprue off the incisal edge. For the super scientific explanation read on:

This optical phenomenon is a result of the flow characteristics of the material. The cylindrical shape of the litihium disilicate crystals promotes an alignment of the crystal structures in the direction of flow. This is kind of like logs floating down a river. The logs will always float end to end and never side to side.

This crystal alignment refracts light in a specific pattern which gives the material a brighter look when viewed laterally (more light refraction) than when viewed from the end (more light penetration). This is not a problem when spruing is accomplished from the incisal edge as detailed in their instructions for use because all the crystals are aligned along the axial surfaces. However, when sprued from the facial, the crystals will remain aligned with the sprue for a distance into the axial wall of the restoration before changing direction to align with the axial surfaces. This creates an optical illusion that there is a difference in the material at the sprue attachment site. This phenomenon will be more pronounced with thick restorations and less pronounced in thin walls where the directional change of the lithium dislicate crystals occurs almost immediately upon the material entering the wall of the restoration.

Wow thanks Sixonice!

[Al.]

On anteriors I dont get it when I sprue on the incisal edge but I do alot of posterior press and stain and there isnt an incisal edge and it seems like no matter where I sprue I get that blister or spot of more trans, so I sprue all the posteriors from the lingual.
On lower anteriors where I press and stain and dont want to mess up the incisal edges or when I cut back for mamelons I sprue on the lingual just below the incisla edge.

Its not the correct place to put the sprue per the manual but it works for me.