Panthera: Selecting the right bar
by Andreas Klie, RDT
What is the most important criteria for an implant bar? Passivity, hygiene, comfort, aesthetics, ease of design and manufacturing.
For any misfit above 10 microns, don’t use bars. 1 micron is 1/1000 of a mm.
Passivity is achieved by: scanner, scan body, implant replica, milling machine.
Accuracy: 5 microns 5 microns 5 microns 5 microns for a total of 20 microns
Panthera accuracy: .5 microns, no scan bodies, 5 microns, 5 microns for a total of 10.5 microns
Inter occlusal space should be less than 10 mm.
Where are the implants being placed and are there any angulation issues?
Factors in your workflow that are critical for accuracy:
Impression taking at the clinic
The scanner that captures the model
Design parameters: there are differences by designs of the bar and by manufacturer
Milling strategies: what is the quality and accuracy of the unit used?
Transformation of the all the above into the final product
What is the passivity of a multi-implant piece?
Precision in microns ( < 10 microns ), level of approval of the technician, level of approval of the dental practitioner, quality of the osteointegration of the implants
The Sheffield test: attach the implants to the bar on one side and push down on the other side to see if there is any rocking or movement. If so, you need to make changes.
Space requirements: inadequate space for prosthetic components can result in an over-contoured prosthesis. You need consensus of what everybody involved thinks will happen and what will be achieved.
Hygiene variance by implant bar type: removable and fixed-removable have the best hygiene potential. Fixed are more difficult to achieve sufficient hygiene protocols.
Implant placements and angulations are a consideration. Is there a proper path for insertion? If not, what are you going to do? Compromise the case, either functionally or financially.
Diamart by Domenico Cascione, CDT. A new type of bar. A primary bar lies under a superstructure in either PMMA or Pekkton. It combines the fit and strength of titanium and the aesthetics of zirconia. It is a fixed design. The titanium substructure supports the cantilever. Therefore the cantilever can be extended. The primary bar allows correction of any implant trajectory. 100% retrievable. Can be made in multiple sections so if a problem arise, the individual section with problems can be modified. If implant axes are not parallel, you can still attach the superstructure and get passivity.
Diamart design creates double the strength compared to a regular bar.
The superstructure design can be created in zirconia, Pekkton or PMMA. The minimum length of the entire product, including teeth, would be 7 mm. You might wish to consider 8 mm or higher as optimal.
3 options: full contour, tooth reduced or full reduction.
Hader bars may require replacing of the nylon bushings every 6 months or so.
Milled bars: better retention for removable restorations. Splintered is likely the better way to go. It is easy to replace attachments. Harder to clean.
Montreal lingual bar, fixed. Hygienic due to being highly polished. Only the labial surface is acrylic. High water design can be utilized. Requires regular servicing.
Wrap around bar: best acrylic aesthetic possible. Fixed. Hardest to clean. Everything is rounded. Made popular with All on 4 cases. No stresses in the acrylic due to the rounded edges. Features a finishing line for the acrylic. Ends at the tissue level.
Dolder: old design. Panthera now feature the Dolder ++. Length has been extended and the gingival area is contoured to fit the soft tissue outline. Less servicing required.
Double structure: easy to clean since it can be patient removed. Bar is sealed under the supra-structure. Provides more stability to the denture. Easier to process for the laboratory.
ReBourke bar: removable fixed milled bar. Two parts. 25 degree angulation in the anterior for better spread of forces. Locked in the posterior with the MK1 attachments. Slight tissue compression to seal the bars. Not a food trap.
Zirconai bar: hygienic, aesthetic, better tissue reaction than titanium, made with Ti bases to prevent micro fissures. Features threads in their design to facilitate ease of removal of attachments.
PEEK: PolyEther Ether Ketone: comfortable due to flexibility. Very strong wear resistance. Lighter than Ti, very biocompatible.
ReBourke Pink: modified pink colour added for improved aesthetics. Otherwise the same as the regular ReBourke bar.
Integrated bar: an angled custom abutment is added to a milled bar. Abutment angles can be up to 30 degrees. Each custom abutment is coded so that you know which goes where and what order to add them. Posts are screwed on top of that and the bar is attached on top of these. Very hygienic.
Patients with dexterity problems: how do you help these types? Panthera Lock “N” Release. Features a custom angulated abutment, a locking mechanism in the front that features a piston, no servicing required. Mandibles only.
Dentures feature a reasonable compromise between features, effectiveness, aesthetics, fixed or removable, and price.
Additional product for sleep apnea: D-DAD device. Smallest on the market. Titration by 0.5 mm. increments, made of type 12 organic polyamide, hydrophobic, bruxism resistant, very comfortable.
These notes were taken by Richard Murray while attending this Denturism Study Club session of March 3rd, 2017 at Central Dental in Markham, ON.
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