Labs Wish Their Dentists Knew About Implants

Tramain Watkins, CDT NDX Muth and Mumma

Tramain Watkins, CDT

Implant therapy is intrinsically interdisciplinary. While there are exceptions, most of the time a surgical specialist, a restoring dentist and a laboratory are all involved in an implant restoration. When each member of this team communicates with all the others, especially before the implant is placed, patients consistently receive optimal treatment. When this communication does not occur, sometimes the results are not what they could be. Here are some considerations from a laboratory perspective that will give consistently better implant-based restorative results in your practice.

1. People buy teeth, not implants: While many of us have heard this saying, it hasn’t yet transformed the way that implant therapy is planned. No matter how much surgical skill was required at the time of implant placement, the patient will usually evaluate the entire result based upon the esthetics of the final restoration.

For this reason, the entire implant therapy team must implement prosthetically driven implant planning, usually by involving lab fabricated or chairside surgical guidance. Additionally, the implant team should challenge ourselves surgically to do what’s necessary to place implants that will create the best restorative result. If more expense in soft or hard tissue augmentation is necessary to achieve that result, we can use our prosthetic plan to show the patient the benefits derived from any additional expense. Conversely, when implants are placed without full awareness of the final restorative outcome, the general dentist and the laboratory must sometimes make compromises between esthetics and function to achieve an acceptable final result.

2. Most implant restorative problems originate with impressions: This truism reminds us that time and expense invested in capturing the correct implant trajectory and rotation at the impression appointment pays dividends in patient satisfaction and time savings at the delivery appointment, and avoids costly remakes. When implant remakes are evaluated in the laboratory, variations between the original and remake impressions usually evince implant capture as the root of the problem.

Periapical radiographs of the seated impression component are a critical tool to create accurate implant impressions. Modern internal connection implants make accurate PAs all the more important, as images captured off angle to the implant platform are not as helpful in ascertaining full seating of the impression component.

Impression technique also significantly affects restorative precision. Closed tray impression copings must be removed and replaced in the impression, introducing variability into the process. Technicians who replace these components in the lab must be highly skilled, creating another variable affecting clinical implant results.

Because the copings are never removed from the impression, open tray impressions are the most accurate physical impressions. While these impressions are more difficult to capture, the time invested during impression taking will pay dividends in ease of delivery and quality of the final prosthetic.

Intra-Oral Scans (IOS) are also very accurate, as long as a few rules are observed. First, it is critical that the entire scanbody be captured in the scan. If the software has to interpolate holes or repair flaws in stitching of the images (often appearing as ridges is the scan), the orientation of the implant in the lab’s design software might not be accurate. Second, the shape of the scan body must not be altered in any way, or the IOS will be unusable in the lab. If the scanbody must be altered due to clearance or angulation issues, an open tray impression should be made instead. Third, IOS systems generate lots of data quickly, and too much data adversely affects the image alignment necessary to create a digital impression. Take the quickest scan that you can capture accurately for best results. Finally, IOS scanbodies with resin interfaces distort over time during disinfection. Follow manufacturer advice for number of uses, or switch to scanbodies with metal interfaces.

3. Analog impressions have open workflows, while digital impressions often have closed workflows: Once you have taken an analog impression, any components that can be physically attached to the impression coping or the analog in the model can be used for a restoration.

However, when a scan body is chosen, you are often (unknowingly) choosing a workflow. Your lab may not be able to use their preferred components or case design for a restoration because the associated workflow is not supported by the digital libraries available with that intra-oral scanbody. This points out two important aspects of selecting a scanbody system. First, talk with your lab before purchasing scanbodies, to avoid creating scans that cannot be used. Some lesser known vendors sell IOS scanbodies that don’t even have an associated digital model workflow in certain laboratory design software. On the other hand, you can purchase scanbodies that require the lab to follow your preferred workflow, or that facilitate your own chairside milling. Also, please help your lab by including scanbody manufacturer and part information on your prescription, along with implant brand and size information.

4. Technology allows us to deliver better implant supported restorations: We can now create custom titanium healing abutments before implant placement whose gingival contour can be exactly replicated in the final restoration once the case is ready to restore. Angled screw offerings are available for most implant systems, allowing us to use screw retained restorations for all of our cases and avoiding the potential of peri-implantitis from cement-retained restorations. Advances in grafting materials and techniques for hard and soft tissues have made these procedures more predictable than ever. There are even some impression capture technologies that can eliminate one chairside appointment for implant supported restorations. Staying abreast of advanced technologies like these allows you to deliver the best possible implant therapy for your patients. Use your lab as a partner in keeping abreast of changes in technology, as laboratories often have strong relationships with the implant OEMs, and can be a great resource to assist you in selecting the best prosthetic workflows for your patients.

5. Implant brand matters: Technological penetration is not uniform across implant brands. Once an implant is placed, your patient’s restorative options have been defined. Intentional collaboration with your surgical specialist in implant selection before surgery will ensure that the restorative option that you want will be available.
Since dental implants are a lifetime restoration, selecting a proven implant company and thorough records of all implant and restorative components will ensure that your patients can continue to use their implants for future restorations. Patients have had stable implants removed for no other reason than a lack of available componentry.

6. Manage implant position: While most of us are familiar with the restorative space necessary for a full arch restoration (15mm from the implant platform to the plane of occlusion), we sometimes do not consider restorative space for single tooth implant cases. However, limited restorative space, especially for posterior cement-retained crowns, can lead to continual loosening of crowns. Sometimes, we must choose an alternate restorative modality or material because of limited vertical clearance above our implants. Not only that, but our platform depth and implant size directly control the emergence angle, dark triangles, and contacts of the final restoration, as well as the position of the hard and soft tissue over time. This is especially critical in the anterior region.

Deliberate collaboration among the members of the implant treatment team is the key to predictable implant restorative results. Take advantage of your implant laboratory’s expertise in prosthetic parts, workflow, troubleshooting, and tooth morphology to get the consistently excellent results that you want for your patients. When the general dentist, the surgeon and the lab work together consistently, patients reap all the benefits of modern implant dentistry.