When Aaron Hoffman, Troy Gooden and Eric Gooden, Co-Owners of Sunflower Dental Studio in Topeka, KS, first saw the impressions for a 20-implant reconstruction, they thought it looked like something from a sci-fi movie. It was the largest case Hoffman had ever had the opportunity to work on during his 19-year career as a ceramist, and he couldn't wait to get started.
1 } The Restorative Challenge
The 80-year-old patient had tremendous decay and bruxing problems and the prognosis of his natural dentition was "hopeless," says his dentist, Dr. Guy Gross, New Horizons Dental Care, Salina, KS. Dr. Gross removed all of the patient's teeth and restored him with a complete set of dentures. However, the patient had a severe gag reflex, couldn't tolerate the dentures and after a few months said, "If you can rebuild my mouth with restorations that function like real teeth and no removable prosthesis, that's what I want."
Dr. Gross explained the various restorative options and price points. The patient opted for the treatment plan he felt would most closely mimic his natural teeth—an implant-supported prosthesis with a total of 20 implants—and fortunately, had sufficent financial resources.
Since he was concerned about hygiene and food traps, he wanted as many single units as possible so he could brush and floss easily. In addition, Dr. Gross and the laboratory discussed the fact that this approach would facilitate replacing any units that might possibly fail in the future.
2 } Implant Placement
Dr. Gross had the patient's denture duplicated in clear acrylic with pilot holes and used it for the surgical stent. He placed all the implants in one appointment, took impressions and sent them to the laboratory. "When we received the impressions, I was overwhelmed by the challenge but also incredibly excited by the prospect of doing that amount of porcelain work," explains Aaron Hoffman, Co-Owner and Ceramist, Sunflower Dental Studio, Topeka, KS.
The lab poured the models and made acrylic temporaries that the patient wore for about two months. Then the healing caps were removed and temporary bridges were placed. Four months later, Dr. Gross placed the abutments and sent the impressions and bite registration to the laboratory.
3 } Fabrication Process
After the copings were waxed up, cast in Ceradium V, a non-precious alloy from Matech, and tried in the patient's mouth, Hoffman went to work fabricating three-unit bridges for #5-7 and #20-22 and 15 porcelain-fused-to-non precious crowns using the VITA® VMK Master System. It took him two 14-hour days to complete all the restorations; he completed all the buildups on the first day and the finishing on the second.
Given the patient's age, Dr. Gross and Hoffman opted to mimic the dentition of a patient who had previously had orthodontic treatment and experienced some mild shifting and slight crowding over the years. "We tried to simulate some rotation and enhanced incisal imperfections to keep his smile natural looking," says Hoffman.
4 } Esthetic Check
To get a sense of how the restorations would look in the mouth, Hoffman created mock lips using red wax. He took photos and used Photoimpression Gold software to edit the photos to give an idea of how the final restorations could be stained and colored and then sent the photos to Dr. Gross for his approval. "This is a great photo editing tool and it allows me to enhance incisal translucency and interproximal shading. I use it to show patients the potential final outcome during shade consults and as a teaching tool when training ceramists," says Hoffman.
5 } The Seating
Upon approval of the photos, Hoffman stained and glazed the restorations and travelled to Salina, about an hour and a half away from the lab, to ensure a one-day seating. The seating process took eight hours. Given the size of the case and the fact that the patient had no teeth, Hoffman anticipated the need to redo at least a few of the restorations but was pleased that none of the units had to be remade. Some contacts on the lowers had to be adjusted and polished but, otherwise, it was a very smooth seating.
"Dr. Gross and I were high-fiving each other. We made the patient's mouth functional in a way it hadn't been in years. Plus we gave him confidence in speaking and eating and probably knocked 20 years off his appearance," says Hoffman.
© 2015 LMT Communications, Inc. · Articles may not be reprinted without the permission of LMT
Rob Teachout, CDT · Professional at Patriot Dental Lab
"Galvanic reactions and non-precious alloys
Whenever two dissimilar metals are in contact with each other...See more an electrical current is
generated. The consequence of the current is dependent upon the materials and
environment. Multiple studiesii,iii,iv have been conducted on the effects of alloys in contact
with titanium implants. Interestingly the studies have been conducted independent of each
other but the results are quite consistent.
Do not use non-precious alloys in conjunction with implants.
Nickel or cobalt based alloys will corrode when in contact with titanium. Table 1 shows the
electrochemical potential for the different alloy systems as determined by the studies. For
any two alloys, the alloy higher on the list will corrode the lower one."
i Special thanks to Pittman Dental Laboratory for their astute observation of this phenomenon.
ii âStudy of Galvanic Corrosion between Dental Alloysâ, Dr. Zurcher, in âBiocompatibility ,allergies and resistance
to corrosion: a global scientific approachâ, pp 43-53 1993, METALOR.
iii âGalvanic corrosion behavior of titanium implants coupled to dental alloysâ, M. Cortada, et al, Journal of Materials
Science:Materials in Medicine,pp 287-293 Vol11,No5, Kluwer Academic Publishers, 2000.
iv âGalvanic corrosion behavior of implant suprastructure dental alloysâ, N.M. Taher and A.S. Al Jabab, Dental
Materials, pg 54-59,Vol 19, No 1 , Elsevier Science, 2004.