A Quick Guide to Proactive Practice and Restoration Lab Communication

Have you ever received "the dreaded phone call" from the dental lab: "Hey Doc, we need more space in order to build the anterior ceramic restorations?" If you have, you know or feel the negative gut response.

A series of thoughts immediately go through your mind:

  1. "I KNOW I provided enough space for the ceramic” ;

  2. "The lab doesn’t really need more space, 'they' are just saying that because it makes their job easier” ;

  3. "The patient is already scheduled for the insert, and I don’t have time to re-prepare and re-impress";

  4.  "Can't the lab 'fudge it' and just make it work?"

These, and maybe some other, thoughts are frustrating and disconcerting for a clinician. We have busy schedules, and these circumstances really throw a wrench into our practice agendas and timetables. This is certainly a challenging situation that is, unfortunately, more common than it should be. So how can we improve restoration lab communication and stop getting those dreaded phone calls?

Read on to find out.

Why Dentist-Restoration Lab Miscommunication Happens

In talking with numerous dental laboratory technicians, limited restoration space issues are a common occurrence. Inadequate space can not only be a problem with ceramic appearance but can also lead to restoration fracture due to thin and inadequate ceramic dimension. Most dentists use occlusion and opposing tooth relationship as the guidepost for evaluating tooth reduction and subsequent space. Adjacent tooth contours are also a reference point when preparing teeth for indirect restorations.

Both perspectives can lead to misjudgment by the clinician, as the clinician's personal calibration viewpoint is often misleading. Bob Winter and I know from our Restorative Design Workshop analysis that most clinicians underprepared tooth contours by as much as 50% (on average). The dreaded phone call is likely to be a common occurrence that is actually fact-based!

Tools, such as silicone reduction guides, can aid in reductive space evaluation (see putty reduction guides at Spear Online). Made from an outcome-based diagnostic wax-up, the reduction guide provides definitive evaluation of tooth preparation contours. In the digital world, a comparison of the tooth preparation relative to the restoration library proposal can provide dimensional insight during the tooth preparation procedures. In the end, however, inadequate or compromised reductive dimension may result in catastrophic results. Although this is not the primary point of this article, it is essential to understand the importance of ceramic thickness and proportions.

Recently, I received one of those dreaded phone calls (Yes, it happens to all of us at one time or another)! All the same thoughts and feelings mentioned earlier immediately went through my mind. However, frustrating as it is (and was) to receive this call, I am reassured by the fact that I have a good relationship with the dental restoration lab, and we can communicate very effectively. I wanted to share this dreaded call experience with the Spear Digest community, as I believe there are some good learning points that come from the outcome that may help you avoid these calls in the future.

Figure 1: Steve-pre-op.

My patient Steve wanted to improve the appearance of his central incisors, relative to his existing lateral incisor implant restorations. At the time of his implant restorative, the central incisor dimensions were altered with composite to improve tooth proportions. In the 10 years since the implant restorative, the centrals are no longer acceptable in appearance. Steve is choosing ceramic veneers of his centrals to improve the appearance. 

Steve Diagnostic wax-up
Figure 2: Steve Diagnostic wax-up.

New casts were obtained, and an additive diagnostic wax-up was fabricated. Corrected tooth contours and restoration fullness provide improved appearance and dimension. Putty guides were fabricated from the wax-up for preparation dimension evaluation and as an index for provisional fabrication. The restorations were to be laboratory fabricated layered Lithium Disilicate (Emax).

Steve- tooth preparations with red lines
Figure 3: Steve- tooth preparations (with red lines).

Teeth #8 & #9 were prepared using techniques and concepts taught in the Restorative Design Workshop. Placement of red lines at the time of tooth preparation limits over-preparation and helps to maintain tooth structure to remain as minimally invasive as possible.

Window guide over the tooth preps
Figure 4: Window guide over the tooth preps.

The silicone window guide fabricated from the diagnostic wax-up is used to verify adequate preparation depth and contour to achieve acceptable ceramic appearance and strength. Necessary contour changes are easily visualized and subsequently adjusted through the application of this guide.

Steve's provisionals
Figure 5: Steve's provisionals.

Provisionals were fabricated using a silicone putty index of the diagnostic wax-up. In esthetic cases, it is particularly important that the provisionals reflect the contours and proportions the patient is requesting. The patient must approve of the shape and geometry created. It is from these provisional dimensions that the dental laboratory sculpts the final ceramic restorations to achieve the desired outcome. Chairside, functional, and esthetic adjustments are made, and a cast of the provisionals is obtained. This model, along with a facebow transfer, opposing model, and bite records, is combined with shade photos, provisional photos, and the completed laboratory prescription, and sent to the dental laboratory. This information is forwarded to the dental laboratory to provide complete and thorough communication and documentation to achieve a predictable outcome.

Camera set up for dental photography
Figure 6: Image of a red phone - "The dreaded phone call".

The case was submitted to the dental lab with an expected and predetermined due date of return. Then, the dreaded phone call! "Hey Doc, we need more space!" How could this be? I followed all the guidelines: prep design, accurate impression, provisionals from wax-up, facebow transfer, etc. How could this be? As frustrated as I was with receiving this call, I am fortunate that I have a good relationship and open communication with the dental laboratory. I was confident that together we could troubleshoot this problem and arrive at a mutually acceptable solution. I returned the phone call to the dental lab, and we began our troubleshooting discussion. 

Occlusal view diagnostic wax-up - Intimate contact with silicone index
Figure 7: Occlusal view diagnostic wax-up - Intimate contact with silicone index.

The technician and I went "down the list" to evaluate and mediate the situation. Definitive Wax-up? Check! Accurate Impression? Check! Level Facebow? Check! Provisional accuracy? BINGO!! The discrepancy is in the provisional, relative to the wax-up! Let's evaluate the situation.

Window guide on the model of the provisional - showing the discrepant space
Figure 8: Window guide on the model of the provisional - showing the discrepant space.

The design and preparation process for Steve proceeded on a normal path. The diagnostic wax-up provided improved and acceptable contours. The teeth were adequately prepared. The PVS impression was accurate, and the bite records provided functional guidance and tooth-to-tooth contacts. Everything checked off, except for the provisional!

It is common for many dentists to fabricate the provisional following the final impression or scan. Alterations of the provisional often occur during this process. Facial contour, length adjustment, and texturing changes are reductive to the overall dimension of the provisional. Minimal adjustment is not an issue. But many times, such as in this case, more significant changes can result from more extensive alteration. These provisional modifications can easily go unnoticed by the dentist but can have dramatic effects on the appearance and/or strength of the final ceramic.

The window guide seen in the accompanying image provides visual proof that significant alteration in the facial dimension of the provisional occurred, relative to the diagnostic wax-up contours. The "negative space" seen between the provisional contours and the silicone index represents the amount of surface contour removed. Although it seemed minimal at the time of alteration, the effects can be catastrophic.

Window guide from lab with minimal space indicated
Figure 9: Window guide from lab with minimal space indicated.

Fortunately, I work with an observant dental laboratory and have a good communicative relationship with them. The dental lab technician reviewed the case and immediately sent me the image seen above. Minimal and limited space for ceramic was easily visualized from this window guide perspective. There was not much discussion to be had after seeing this situation! It is obvious that I had now compromised the outcome by inadvertently and non-strategically adjusting the provisional contours. The technician offered two choices for "recovery". First, a re-preparation and new impression/scan would be ideal. This meant, however, a re-appointment, patient inconvenience, and a significant delay in final delivery.

Reduction coping from the lab
Figure 10: Reduction coping from the lab.

The second alternative offered was to fabricate a reduction coping that would indicate specific areas to be adjusted at the time of restoration try-in. This avenue was only possible because the surface recontouring involved facial aspects only. There was no tooth length reduction required. Although not as ideal as re-preparation, the technician felt confident this would be an acceptable compromise.

Reduction coping on the teeth
Figure 11: Reduction coping on the teeth.

The reduction copings were tried in, and the excess tooth structure was identified. Selective recontouring of the preparation was accomplished with a low-speed handpiece and a fine diamond bur. Try-in of the veneers for fit and color verified adequate reduction was complete. 

Final ceramic restorations
Figure 12: Final ceramic restorations.

Once the restorations fit properly following coping reduction, the adhesive process continued without concern. The patient was pleased with the outcome, and veneer longevity was not compromised.

Anterior esthetic restorative dentistry is complex. Many factors come into play to achieve desirable and long-lasting outcomes. Strategic processes and multiple steps are involved in achieving success. There are many chances for things to go awry. Problems do occur. A crucial and important preventive aspect is to work with a dental laboratory that has your back and supports you with quality craftsmanship and effective communication. Things can, and do, go wrong. In complicated and complex situations, it happens. But working with an engaged, supportive, and communicative dental lab will help alleviate many of these frustrating situations. So, when the dreaded phone call from the dental lab comes, the stress and anxiety experienced by so many other dentists will not be as dramatic. I hope this article helps you become aware of the importance of not only an ideal wax-up and good provisional contouring but also the significance of working with an outstanding dental lab.

How Communication Leads to Resolutions in Dentistry

The miscommunication between the dental lab and the dentist occurred when significant alterations were made to the provisional restorations, compromising the outcome relative to the diagnostic wax-up. This discrepancy was identified through visual proof provided by the window guide sent by the dental lab, highlighting the need for adjustments. Effective communication and collaboration between the dentist and the dental lab technician allowed for the identification of the issue and the implementation of solutions, such as using reduction copings to indicate specific areas for adjustment, ultimately ensuring the success of the final ceramic restorations.

Problems can, and do, occur in dentistry. They (like this case) are frustrating, to say the least. Troubleshooting situations before a problem occurs can lead to better and more predictable outcomes. Along this line, Frank Spear is presenting a two-day seminar live at Spear campus. "Targeting clinical success: Reducing Risk of Failure.” Take advantage of this live opportunity so you can avoid the dreaded phone call.

 Jeffrey Bonk, D.D.S., is a member of Spear Resident Faculty.


Commenter's Profile Image Edward R.
April 2nd, 2024
Hi Jeff, I loved your article! That article is the heart and soul of why I am at Spear. Patients often fall into the crevasse of bad experiences when lab communication goes wrong. My ambition is, like you, to "build the bridge" across the crevasse for a better patient experience. Cheers, Ed