Inside Dental Technology
A Case of Congenitally Missing Laterals
Challenging cases require careful scheduling to achieve a highest level of success.
As dental technicians, it seems inherent in our nature to wait until the last minute to finish our cases. Let’s be honest. No matter how much time we get to fabricate a case, we always finish it the day before it is due. It is truly an area that the author believes he might need the most help improving. Procrastinating becomes even more critical as the complexity of today’s cases require more physical working time. Stacking porcelain on a few units is fairly easy under most scenarios, but in recent years case involvement has become a much more time-consuming process and adds valuable time to getting a case out the door. The days of receiving case impressions with a shade and due date is becoming a thing of the past. Each case on the author’s bench seems to require a deeper involvement with the prescribing dentist, and often the patient. This becomes a problem for someone who is used to leaving things to the last minute.
As we work to improve our scheduling process, it is important to remember and include all aspects of the case that may impact its completion. Case evaluation, for example—unless it is an old-school, single-posterior case with photographs for shading—often requires extra time to consult with the doctor and sometimes the patient. Photographs are taken chairside, a cast is mounted for the functional evaluation, and esthetic requirements are created. The phone conversations alone can be very time-consuming, which takes away from time spent at the bench.
The diagnostic phase also needs to be considered when scheduling a case. This process includes a functional/esthetic wax-up or tooth set-up with cast duping and cross-mounting of all casts, which can add a great deal of time-consuming physical labor to the process. Impression and casts is often a step that we rush through, but in the author’s laboratory this phase alone may add 3 to 5 days to the case. We have strict standards on pouring and cross-mounting our casts for accuracy, and these protocols add more time to the case schedule. Once all of the casts have been mounted, case evaluation and substructure design requires a discussion by the team and cross-checking the casts and mount in relation to the photographic information provided by the dentist. This can sometimes call for a follow-up phone conversation with the doctor. Once these phases of the case are completed, we still need to leave room in the schedule for ceramic layering. In the author’s laboratory, there is usually a 2- to 3-week wait period from this point to completion. The author finds that once he begins to work on the case, almost as much time is spent evaluating the color based on submitted photographs, shade-mapping sheets for reference for possible future work, and taking photographs for lectures and articles as the actual ceramic building process is set in motion. This is why leaving things to the last minute is no longer an option for the author.
The Challenge of Combination Cases
Most of the recent cases coming into the author’s laboratory have at least one implant-supported unit. Combination-type cases always challenge the technician’s choice of substructure and materials for the final restorative. Although the same criteria for scheduling applies to a case like this, the extra steps needed for completion present even more of a challenge and cannot be rushed.
A conversation with the dentist revealed that our patient presented with congenitally missing laterals and was a high esthetic risk because of her high smile line resulting in a large amount of gingiva showing during a normal smile (VME, vertical maxillary excess). Implants were placed in the No. 7 and No. 10 tooth positions. When there is a gingival component involved in the case, it is challenging not only to match one or two teeth into the oral environment but also make them blend into the tissue without creating a “gingival” color discrepancy (Figure 1 and Figure 2). Shade photographs were taken for color and a lingual photograph was taken to evaluate the lingual aspects of the teeth and restoration (Figure 3 and Figure 4).
The cast work was completed and soft tissue was used in the area of the implant replicas. The tissue on the cast can be evaluated for tissue thickness to determine what restorative material would work best. Because the patient had VME, it was important to understand what type of tissue was involved. Thin biotype tissue would require a colored implant abutment such as a zirconia or a ceramic-coated metal abutment, whereas a thicker biotype tissue would mask more of the implant substructure (Figure 5 and Figure 6). The soft tissue on the cast was shaped to support the proper emergence of the future restorations. Nature is always the best example of the natural root shape, and it should be copied onto the cast (Figure 7). Because of the tissue biotype and the implant used, it was decided that a metal implant with a ceramic margin would best help with the final tissue color.
The implants were fabricated and ceramic shoulder material was applied to create the proper contour. The ceramic shoulder material is also highly fluorescent, which helped with the final gingival coloration (Figure 9 and Figure 10). Because the emergence profile was established on the cast, the only concern before fabricating the final restorations was to ensure that the margins were in the proper position. In an ideal situation, it is best to keep the marginal finish line 0.5 mm below the gum line. This will allow for the best esthetic result and the easiest position for the dentist to clean off excess cement after final placement (Figure 11 through Figure 13).
Metal copings were fabricated, opaqued, and the ceramic margins were applied to the pre-existing margins fabricated on the abutments (Figure 14). The final ceramic was fabricated with the use of the shade-mapping sheet and checked on the cast (Figure 15 through Figure 17). After the implant abutments were screwed into place, the final restorations were temporarily cemented. Photographs taken on the day of insertion demonstrated that the overall look worked out well (Figure 18 through Figure 20).
Although the clinician used a “colored” temporary cement, the author would always advise that any restorations with ceramic margins placed with temporary cement will not allow proper light transmission and may have a negative color influence on the final restoration. There are “clear” temporary cements that are suggested for this situation.
The author would like to thank Dr. Haig Rockery for his clinical work in this case.
About the Author
Peter Pizzi, CDT, MDT, FNGS
Owner and Manager
Pizzi Dental Studio, Inc.
Staten Island, New York