UCLA Abutment
Posted on 07/29/2011
As discussed in the previous day's blog, we have classified the three common abutment types as (1) Prefabricated Metal Abutment, (2) UCLA Abutment, (3) Ceramic Abutment. Today, we will focus on the UCLA Abutment.
According to Frank Spear, DDS, MSD (JADA Vol. 140 - http://goo.gl/BwKBd) the UCLA abutment was invented by Dr John Beumer at the University of California Los Angeles in 1988 - thus the name "UCLA". The unique aspects of the UCLA abutment were:
1. The abutment screws directly into the implant without the use of a transmucosal abutment cylinder*
2. The abutment is made from a castable material - in most cases plastic or plastic with gold base.
There were several discernible advantages to this style abutment over earlier metal abutments. The chief advantage is the flexibility: the lab could wax and cast the plastic part using the lost wax technique to achieve virtually any style abutment indicated. Here is a short list of some of the advantages:
1. The lab can make a patient specific collar depending on tissue height.
2. The lab can make a patient specific angulation to address implant fixture angulations issues.
3. The part could be used for either screw retained or cement retained final restorations.
The UCLA abutment can come as either a completely plastic abutment which is cast in any alloy the doctor or dental lab requests (although it is preferred to us at least a noble alloy**), or a gold base with a plastic castable extension. The advantage to the latter style - the gold base - is that the base is machined, offering typically a more consistent fit with the implant fixture. A completely plastic UCLA abutment requires that the lab tech be very experienced with semi-precision castings to ensure the interface connection is accurate.
The only major disadvantage to this style of abutment is the rising cost of precious metals - which creates for unpredictability with the final cost of the abutment. Since it is recommended to use a gold or palladium majority alloy the alloy used for the abutment can become quite expensive.
However, from our experience, the plastic/gold UCLA is still the best option for complex implant restoration. Its flexibilty allows for almost any abutment shape and contour - something not possible with pre-fabricated abutments and sometimes not achievable with CAD/CAM.
References
*The UCLA Abutment: A Four Year Review by Steven G. Lewish DMD and D. Llamas, DDS and S.Avera. University of California, School of Dentistry, Los Anageles Calif April 1992 - available in the Journal of Prosthetic Dentistry April 1992, Volume 67 Number 4.
**Galvanic corrosion behavior of titanium implants coupled to dental alloys: M. Cortada, LL. Giner, S. Costa, F.J. Gil, D. Rodriguez, J.A. Planell. Journal of Materials Science: Materials in Medicine 11 (2000) pages 287-293. Online at: http://goo.gl/VgaQA
According to Frank Spear, DDS, MSD (JADA Vol. 140 - http://goo.gl/BwKBd) the UCLA abutment was invented by Dr John Beumer at the University of California Los Angeles in 1988 - thus the name "UCLA". The unique aspects of the UCLA abutment were:
1. The abutment screws directly into the implant without the use of a transmucosal abutment cylinder*
2. The abutment is made from a castable material - in most cases plastic or plastic with gold base.
There were several discernible advantages to this style abutment over earlier metal abutments. The chief advantage is the flexibility: the lab could wax and cast the plastic part using the lost wax technique to achieve virtually any style abutment indicated. Here is a short list of some of the advantages:
1. The lab can make a patient specific collar depending on tissue height.
2. The lab can make a patient specific angulation to address implant fixture angulations issues.
3. The part could be used for either screw retained or cement retained final restorations.
The UCLA abutment can come as either a completely plastic abutment which is cast in any alloy the doctor or dental lab requests (although it is preferred to us at least a noble alloy**), or a gold base with a plastic castable extension. The advantage to the latter style - the gold base - is that the base is machined, offering typically a more consistent fit with the implant fixture. A completely plastic UCLA abutment requires that the lab tech be very experienced with semi-precision castings to ensure the interface connection is accurate.
The only major disadvantage to this style of abutment is the rising cost of precious metals - which creates for unpredictability with the final cost of the abutment. Since it is recommended to use a gold or palladium majority alloy the alloy used for the abutment can become quite expensive.
However, from our experience, the plastic/gold UCLA is still the best option for complex implant restoration. Its flexibilty allows for almost any abutment shape and contour - something not possible with pre-fabricated abutments and sometimes not achievable with CAD/CAM.
References
*The UCLA Abutment: A Four Year Review by Steven G. Lewish DMD and D. Llamas, DDS and S.Avera. University of California, School of Dentistry, Los Anageles Calif April 1992 - available in the Journal of Prosthetic Dentistry April 1992, Volume 67 Number 4.
**Galvanic corrosion behavior of titanium implants coupled to dental alloys: M. Cortada, LL. Giner, S. Costa, F.J. Gil, D. Rodriguez, J.A. Planell. Journal of Materials Science: Materials in Medicine 11 (2000) pages 287-293. Online at: http://goo.gl/VgaQA
