Restoring Teeth with Implants

I had a post a while back about implants and want to follow up on that. I have a couple implant cases and wanted to share the process of restoring the implant.  As I've explained to patients at school and friends, a dental implant is basically the "root portion" of the tooth. The titanium implant is placed, and allowed to integrate with surrounding bone. Once the implant is deemed integrated and stable, then we can restore it with a crown. At UB as pre-doctoral students, we do not do immediate loading cases, but this is possible in some cases.

After 3-6 months, once the implant has osseo-integrated (bone has grown into the threads of the implant) we can begin the restorative phase. 

I. Data Gathering/ Treatment Planning

This case involves a patient who is seeking implant restoration of tooth #5. No significant medical history. 

Dx cast occlusal 

Dx casts lateral

Dx wax up #5 occlusal

Dx wax up #5 lateral

The process began with diagnostic impressions and treatment planning. There was adequate interocclusal and mesio-distal space for implant restoration. A 4.2mm Straumann Narrow Collar (NC) SLA Implant was selected for placement by the surgeon. A surgical guide made from TRIAD material and a radioopaque cylinder was fabricated to assist the surgeon in placing the implant with the correct angulation. This is important because implants must be at least 1.5mm from adjacent teeth and if implants are placed next to each other there should be at least 3 mm of bone between them.The patient returned for a try-in appointment where one periapical radiograph was taken to ensure correct angulation with regard to adjacent teeth roots, and to ensure the guide fit passively and completely. 

TRIAD surgical guide

Next, the surgeon scheduled the patient for implant placement. A full thickness flap technique was utilized and the guide was used for initial osteotomy.  The implant was placed without complication. The patient was then allowed to heal for 4 months. Upon follow up with the surgeon, the implant appeared to have integrated with bone well, and I was notified that restorative phase of treatmnt could begin.

The patient was appointed for a closed tray implant impression. Prior to the appointment an impression post, cap and analog were secured from Straumann. A custom tray was also fabricated for the impression making. 

II. Soft Tissue Model Fabrication

Straumann Implant components

TRIAD Custom Tray

At the impression making appointment, the patients vitals were taken, and the procedure was explained to the patient. The healing cap was removed from the implant, gingiva was healed very well. The impression post was then inserted and screwed into the implant so that the arrows on the post were oriented bucco-lingually. The patient was given a cotton roll to bite on posterior to site #5 to prevent damage to opposing teeth from the impression post. A periapical radiograph was taken to ensure complete seating of the impression post. Once complete seating was confirmed, the yellow impression cap was placed onto the impression post, and the impression was made using Aquasil Light and Medium Bodied Polyvinyl Siloxane impression materials. 

Closed Tray fixture level impression 

The impression was inspected and decided to be adequate. The impression post and cap come out with the impression. The post is unscrewed, and in it's place the implant analog is screwed into the impression.

This impression was used as a soft tissue model. In the lab, separator was applied on the impression material around the implant analog. Gingifast was then applied around the implant to simulate the gingiva and help us plan how we will develop emergence profile in the gingiva. Separator was then applied on the Gingifast after 2-5 minutes once the material cures. Separator is applied twice because we do not want the gingifast sticking to the impression, or to the stone. The impression was then poured using Jade Stone. 

Creating soft tissue cast

Soft tissue cast

III. Provisional Abutment/Crown Fabrication 

This soft tissue cast will now be used to select our provisional abutment, fabricate a custom abutment  if necessary and a provisional crown. Provisionals will help us develop the gingival emergence profile before the definitive crown is cemented. 

The next step was to secure a provisional abutment from Straumann. The components arrived in about a week.

Provisional abutment and screw

Soft tissue cast, provisional abutment & Straumann screwdriver

The implant analog was unscrewed from the cast and we were left with a cast replicating what is present in the mouth. We can now see the gingival height and shape we will be working with. We've learned a number of times that an implant is not a tooth. It's actually nothing like a tooth. It is ankylosed, lacking a periodontal ligament, and emerges from the gingiva in a circular shape. With this procedure we are hoping to achieve a more tooth-like gingival architecture surrounding the eventual crown. The provisional abutment here is screwed into place. And any undercuts on the mesial and distal of site #5 have been blocked out with wax.

Next this provisional abutment was etched, to enhance the bond of the PMMA acrylic. 

The abutment was then marked and cut down so that my template could be used to fabricate a provisional crown. 

The access to the screw channel needed to be maintained so that I would be able to retrieve the provisional crown. A hole was made in my vacuum-formed template to accommodate the screwdriver at the correct angulation. The provisional stump was also trimmed further to accommodate my vacuum-formed template of #5

This step was particularly tricky. . The PMMA was then mixed to the "doughy" state and the template filled around the screwdriver. The template-screwdriver apparatus was then brought to the cast and seated and re-seated a number of times as the PMMA set so that the crown would not lock into any undercuts that may have been missed during the block out.  The seating and reseating was done by basically screwing and unscrewing the provisional into the implant analog a number of times gently. 

The provisional eventually self cured and was removed from the vacuum-formed template, trimmed and polished with Acrylustre. The Gingifast was trimmed minimally into an oval shape buccolingually which will allow the provisional to create the emergence profile we are looking for in the mouth. The surface of the provisional contacting gingiva was highly polished to discourage any plaque accumulation.

Occlusion was checked with the opposing cast and we are ready for try in!