Internal Hex vs External Hex Configurations: Long-Term Studies?

The reason to go away from external Hex is that it puts much more force on the implant screw. It becomes almost like the endo tooth that is nothing but a post protuding from a root, yet is supposed hold a crow for years. Screw loosening problems went away with internal hex.

Dr. Nelson , I agree with you.

I now do 50/50, and can say that if you plan correctly and have a good lab, shouldnt have to go with internal. I have had only 3 screw loosenings in 15 years (almost 4000 branemark external hex)so.... if its easier for you, Id say if it aint broke dont fix. internal has advantages but also has disadvantages so its not the "panacea". good planning and execution is the way to avoid problems.

From an enginering point of view, the internal hexed implant with a Morse taper on the hex plus the screw is definately a better connection that an external hex implant that absolutely depends on the screw to hold the abutment in place. If my memory serves me correctly, it was Dr.Leonard Linkow who introduced the internal hex implant to dentistry ( in the 60's), based on a design copied from the furniture industry where adjustable legs are incorporated.Just examine an ajustable leg... a brass fixture with an internal hex that allows it to be screwed into the wood, and an internal threaded channel that allow the leg to be screwed up or down to give the desired height. With all due respect to Dr. Gerry Niznick, he was most probably a track and field star in his youth, and outran Dr. Linkow to the patent office to have the concept of internal hexed implant patented.The granting of this patent held the implant industry hostage for more than 20 years, which necessitated other manufacturers to stick to the external hex implants...after the patent expired, most of the extra hex companies switched to internal hex It is yet to be decided who incorporated the Morse taper for dental implants. I have heard through the grapevine that Gerry Niznick is back training on the running track, so who knows what his next patent will be...... but you can be sure he will be out in front of the pack.

Gerald: You are correct.

There is enough evidence for using external or internal hex connections,we are still asking us each other about our skills and trying to find out answers we would like to hear.Stop that! Hybrid restorations and all that stuff of computerized procedures,teeth in one day, two days, one week .....need to be done with externally hexed implants,since even the computer systems program implants axis - off... Niznick internally implants,Straumann,Astra and Steri Oss implants are excelent solutions for single implants restorations Note: Nobelbiocare Implants are a copy of Steri Oss implants

The issue for consideration is the complexity of the case. If it is a more than one implantt prosthesis and you prefer screw retained restorations on multi unit abutments ,then any connection will work fine. On the other hand for single teeth you are better off, concerning screw loosening ,if you use an internal ,conical connection, either you work at implant level or on abutment for cement retained crown because the EX Hex some times does not have enough anti rotational effect. Also some times it is traumatized and rounded if the surgeon uses to much insertion torque.

External hex is hexed. Passivity is virtualy imposssible with splinted. It tollorances for a single restoration is troublesome. Splinted (laser welded )( not Soldered)is ok but internal and internal with external stablised rings shine, The micro gap is superior and stabilation is better. However, the older cases were off surgically over 60 degrees in angulation so the external worked better. These days, the angulation is better due to bone grafting and better understanding of placement thru stents and proper diagnostics.Connection of the abututment has seen many improvements. Check out Dr Ledermann's work. Jerry Niznick is astute as the North Americian patent king. He is almost retired.

I think it will depend on the complexity of the case you are restoring. The internal hex is a nicer option for single restorations. If you have a larger restoration in mind, the external hex is better. The reason for this, in my opinion, is that most of the time the implants are not going to be parallel. The technician will more than likely use an abutment that is NON-engaging (the hex is not engaged), only the periferal points of the hex are used. This makes for a simpler path of insertion for technician and practioner.

In my opinion the only indication for external hex implants is on bar overdentures. The great majority of cases today are single tooth replacements. The external hex connection is prone to screw loosening. The internal connection, whether hex, morse taper, trilobed, etc... is a far better connection in many ways (micromovement, seal, platform switching, etc...) Most implant systems with internal connections offer ease of impression taking and correction of off angle implants. There is a difference.

Carlos, You can also use internal hexed implants with a bar OD case. I use Pittman Dental Laboratory in Gainesville, Ga. USA. They do a great job!

Check Screw Indirect implant from ID. The definitive solution for bars, overdentures and hybrids. Jerry Niznick is not retired but very active, in fact I will say that he is ReActive and his company is growing world wide at a 70% rate per year!!!!! Great products with incredible quality and a nice price in top of it. My view is trilobe for the maxilla and before Id it was ext Hex for the mandible but now I do both with Id internal trilobes due to the different external implant threads configuration.