Glad to hear Biohorizons is finally getting a keyless system. I know it's a relatively minor thing, but it is a major reason why I chose a different system for my office.
Dr. Nesnick is correct. The advantage of the deeper conical interface is that the abutment can bounce off the internal walls of the implant, which helps the doctor determine the correct path of insertion where the hexagon engages, and finally, the conical seal is made.
The proposed theory suggesting that the medialization of the platform interface leads to a positive bacterial response has yet to be substantiated. Tissue-level implants lack an interface near the bone. Recent systematic reviews have found no difference in crestal wound healing between two-part “bone-level” implants with or without platform switching. Another systematic review compared all three implant types and concluded that there was no statistically significant difference in crestal wound healing among each implant design. However, three studies reported a slight improvement with platform-switched implants, which was not clinically significant. It appears that platform switching has a clinically insignificant effect, but the underlying reason remains undefined.
I beg to disagree. The mating hexes engages first and both index and guide the abutment to full seat. The conical connection, whether 45 deg or 78 degrees, does not provide any guidance or centering because it only makes contact when the abutment is fully seated. The steeper the angle of the conical connection, the thinner the walls on the narrow implants and 6mm implants may be impossible to make.
That would be true if the hexagon were placed along the long axis of the implant or the “path of the draw”. When the hexagon strikes the internal wall of the conical interface, it provides tactile feedback that enables the doctor to realign the abutment until the hexagon engages at the bottom of the interface. I will make a video to illustrate the process.
An argument could be made that the 45 degree bevel centers the hex in the implant better, guiding the male hex to mate with the female hex because the 45 degree lead-in bevel is a shorter funnel than BH’s 82.5 degree funnel. The 45 degree bevel on the implant will be encountered within the first 1/2mm of abutment seating whereas the 82.5deg. Bevel is about 1.5mm deep and the male hex may not make any contact until the bottom of the bevel is encountered. As for the steeper conical connection having more platform switch, if that is the case with BH it has nothing to do with the angle of the bevel . It relates to the diameter of the implant in relationship to the diameter of the internal shaft. Besides, studies show no significance difference related to bone loss where internal conical connections are concerned. issuu.com/dr.niznick/docs/02-28-2012_coir_article_refuting_pl?e=0
You are correct, there are concerns when selecting a deep conical over a shallow conical interface. When the implant has a deeper conical interface it usually results in less volume of metal around the crestal region of the implant which can lead to mechanical complications. One way to mitigate this concern is to use a stronger titanium like grade 23 which is 36% stronger than grade 4 titanium. An additional risk reduction technique is to maximize the volume of titanium at the implant crest which is typically accomplished by not running the major threads all the way to the platform of the implant.
The deep conical seal is the best implant/abutment switch platform connection.
Glad to hear Biohorizons is finally getting a keyless system. I know it's a relatively minor thing, but it is a major reason why I chose a different system for my office.
It is the Hex on the abutment that guides the seating. The mating conical surfaces only make contact on full seating
Dr. Nesnick is correct. The advantage of the deeper conical interface is that the abutment can bounce off the internal walls of the implant, which helps the doctor determine the correct path of insertion where the hexagon engages, and finally, the conical seal is made.
he says we don't know why platform switching is so good, but we do know that. It's because it keeps the plaque away from the crest of the bone
The proposed theory suggesting that the medialization of the platform interface leads to a positive bacterial response has yet to be substantiated. Tissue-level implants lack an interface near the bone. Recent systematic reviews have found no difference in crestal wound healing between two-part “bone-level” implants with or without platform switching. Another systematic review compared all three implant types and concluded that there was no statistically significant difference in crestal wound healing among each implant design. However, three studies reported a slight improvement with platform-switched implants, which was not clinically significant. It appears that platform switching has a clinically insignificant effect, but the underlying reason remains undefined.
TY
I beg to disagree. The mating hexes engages first and both index and guide the abutment to full seat. The conical connection, whether 45 deg or 78 degrees, does not provide any guidance or centering because it only makes contact when the abutment is fully seated. The steeper the angle of the conical connection, the thinner the walls on the narrow implants and 6mm implants may be impossible to make.
That would be true if the hexagon were placed along the long axis of the implant or the “path of the draw”. When the hexagon strikes the internal wall of the conical interface, it provides tactile feedback that enables the doctor to realign the abutment until the hexagon engages at the bottom of the interface. I will make a video to illustrate the process.
An argument could be made that the 45 degree bevel centers the hex in the implant better, guiding the male hex to mate with the female hex because the 45 degree lead-in bevel is a shorter funnel than BH’s 82.5 degree funnel. The 45 degree bevel on the implant will be encountered within the first 1/2mm of abutment seating whereas the 82.5deg. Bevel is about 1.5mm deep and the male hex may not make any contact until the bottom of the bevel is encountered. As for the steeper conical connection having more platform switch, if that is the case with BH it has nothing to do with the angle of the bevel . It relates to the diameter of the implant in relationship to the diameter of the internal shaft. Besides, studies show no significance difference related to bone loss where internal conical connections are concerned.
issuu.com/dr.niznick/docs/02-28-2012_coir_article_refuting_pl?e=0
I thought deep conical is bad because it takes a lot of space and makes the implant weaker
You are correct, there are concerns when selecting a deep conical over a shallow conical interface. When the implant has a deeper conical interface it usually results in less volume of metal around the crestal region of the implant which can lead to mechanical complications. One way to mitigate this concern is to use a stronger titanium like grade 23 which is 36% stronger than grade 4 titanium. An additional risk reduction technique is to maximize the volume of titanium at the implant crest which is typically accomplished by not running the major threads all the way to the platform of the implant.