Inside Dental Technology
June 2014, Volume 5, Issue 6
Published by AEGIS Communications
Education, Communication, and Technique
Building a foundation for restorative success
Fabricating restorations that are both functional and esthetic can be challenging for ceramists and laboratory technicians, as there are many influencing factors that play a role in determining treatment outcomes. Patients present with myriad conditions and desires that dentists must then incorporate into the decision making process. Upon careful consideration, they must then work closely with ceramists to select the most appropriate materials to develop the ideal restoration. This has never been more important than it is today, when increases in the use of all-ceramic restorations and advancements in technology have given rise to enhanced treatment alternatives, allowing ceramists and dentists to plan and design metal-free restorations in previously unexplored ways.1
To best approach the design and fabrication of restorations, it is necessary for ceramists to commit to incorporating three key areas: education, communication, and technique. Together, these three areas help to guarantee clinical success and patient acceptance of proposed treatments.
“Education is the most powerful weapon which you can use to change the world.”
Ceramists, like dentists, must remain educated about the variety of materials and techniques available for use when creating restorations. They must specifically stay informed about optical and esthetic properties of materials, technological advancements, and the effects of techniques such as layering on restoration esthetics and strength. Additionally, it is their responsibility to remain abreast of the latest diagnostic tools available that can reveal information essential for recommending permanent treatments to their patients.2
Given the importance of education in determining proper treatment, it behooves ceramists to take advantage of the multitude of options available to broaden their knowledge. Conferences, hands-on workshops, study clubs, and seminars available from manufacturers and technical professionals all provide ample information about recent material and technology developments. Education is not only critical for ceramists when making appropriate material selection, but also for improving their communication with dentists.
“Communication—the human connection—is the key to personal and career success.”
~Paul J. Meyer
Sharing required information is the foundation of success for dentists and ceramists. Yet, communication between dental laboratories and dentists is often not up to par and, in fact, could delay procedures and compromise results.3 Indeed, according to a 2008 American Dental Association study, over 80% of dentists reported returning restorations to the laboratory because they were incorrect.4 Thus, the need for accurate communication methods is imperative.5,6
When determining a specific restorative option for a patient, several diagnostic tools should be used to understand and communicate the patient’s desires and any limitations of the available treatment options, as well as enable the ceramist to design the ultimate restoration.7 Providing pre-operative photographs of the patient allows the natural dentition to be studied in more depth. Through the use of programs such as Lightroom by Adobe, pre-operative images can be reviewed and the color balance of the images can be corrected and can enhance the evaluation of the pre-operative situation, helping to determine desired shade, contours, and level of opacity and translucency.
Mounted diagnostic casts are also necessary communication tools for dentists and ceramists.8-11 Based on preoperative impressions, they permit ceramists and dentists to clearly identify functional or occlusal problems affecting proposed restorations.7 In turn, they enable ceramists and dentists to develop diagnostic wax-ups that facilitate greater patient assessment and acceptance of the planned treatment, in addition to being another tool that allows ceramists and dentists to anticipate potential problems that the treatment may cause.9,10 Wax-ups also serve as an accurate guide for clinicians and enable ceramists to develop proper contours for the restoration.9-11 Provisional restorations also serve as an important communication tool, despite being fabricated after diagnostic models have been studied and the wax-up completed.7 Provisional restorations, once placed in the patient’s mouth, give patients the unique opportunity to experience what their definitive restorations will be like, without the permanency. This allows patients to share feedback about the function, fit, and esthetics of the restoration.12 This information is invaluable to clinicians and ceramists, since—in an ideal situation—the only difference between provisional and permanent restorations is the material used, so patients are truly experiencing how the proposed restoration will affect them.12
Overall, using tools such as photographs and wax-ups have been shown to enhance communication between dentists and ceramists, and increase patient acceptance during treatment planning.13
“Technique is the beginning, the basic mechanical skills we learn over and over until technique fades into the background, becoming second nature, and our minds become free to envision and create.”
With material advancements, such as metal-free lithium disilicate, come significant developments in the techniques used to treatment plan and design restorations. Ceramists owe it to themselves, dentists, and patients to stay abreast of these trends by educating themselves on new materials, the techniques involved with them, and the benefits they will bring.
Pressable lithium disilicate (IPS e.max® Press, Ivoclar Vivadent) restorations, for example, are fabricated using a hot-wax press technique.14,15 Mastering this technique guarantees more than esthetic restorations for the patient—the preparation for this material is minimal, so the risk of pulpal damage is considerably reduced.16 Additionally, restorations fabricated from this material decrease the chances for postoperative periodontal issues, as the margins are thin and usually end at or slightly above the free gingival marin.16 Perfecting this technique also ensures that occlusion and anterior guidance can be maintained, assuring the patient of a comfortable restoration.16 Because this pressable material dictates these restorations be cut back and layered, ceramists can maintain esthetics without compromising on strength. Mastery of techniques is necessary to know what new materials can achieve for patients; therefore, it is essential for ceramists to avail themselves of opportunities to practice and master new techniques as appropriate for materials being used.
In the case of a 35-year-old woman, the three main tenants of education, communication, and technique were significant to treatment planning and, ultimately, to the fabrication of the ideal restorations. The patient presented with a desire to improve the appearance of the restoration on tooth No. 9. At the age of 12, she fractured a large portion of this tooth in a bicycling accident. Her dentist at the time restored the tooth by placing a direct composite resin, which, due to the trauma that was inflicted from the accident, significantly darkened the entire tooth over time (Figure 1 and Figure 2).
The patient desired a minimally invasive, metal-free restoration to replace the current one. She was interested in using an all-ceramic material to not only improve the esthetics of her tooth, but also the contour. After discussing treatment options, an all-ceramic restoration was decided upon (IPS e.max® Press) to fulfill the patient’s requests and allow a natural flow of light through the restoration that would mimic tooth No. 8. Education and technique were critical factors in this decision, as the choice to employ lithium disilicate requires a thorough understanding of the material itself and careful mastery of the techniques used to design the restorations. The manufacturer’s instructions and several classes about the material itself provided the necessary knowledge base for working with this material, and independent studies and applications in the laboratory provided the hands-on technique development required to design the restoration.
Pre-operative photographs were taken and sent to the laboratory, which were essential to determining the ingot and layering porcelain to be used (Figure 3 through Figure 7). Additionally, impressions, bite registration, and other records were taken and sent to the laboratory to provide necessary occlusal information for a properly fitting restoration, after which the provisionals were placed.
The patient visited the laboratory for detailed shade mapping (Figure 8). Information obtained during this visit, in conjunction with the photographs provided by the clinician, proved essential for shade selection. A brighter shade ingot was required to mask the darker original preparation color, so ingot shade LT (low translucency) BL3 was chosen. The LT ingot would maintain the chroma more effectively than the HT (high translucency) ingot, which was necessary for this case.
It was also necessary to design the restoration to mimic tooth No. 8, which presented with multiple variations in color. Therefore, achieving the correct shade under several different types of light—particularly natural light—was important; otherwise, the patient’s restoration would appear too bright. Here, the pre-operative photographs proved most useful, as their evaluation under low light revealed greater translucency in the incisal middle third of tooth No. 8, which appeared orange and blue. This information communicated the appropriate levels of translucency, opacity, and other esthetic characteristics needed for the restoration based on the appearance and structure of tooth No. 8. An exact match was not desired, however, as this would cause the restoration to appear unnatural. Additionally, high contrast photos in black and white were useful in determining the appropriate ceramic shades and expose the detailed characteristics of tooth No. 8 (Figure 9 and Figure 10). Lateral views of the restoration determine proper reflective and deflective areas in addition to the evaluation of facial lobes.
The working model was fabricated and mounted to the Stratos 200 (Ivoclar Vivadent) articulator, evaluated, and prepared for application of wax (Figure 11). A full-contour wax-up was created to mimic, but not mirror, tooth No. 8 (Figure 12), and evaluated to determine correct reflective and deflective zones (Figure 13). Madame Butterfly red silk was applied to the facial surface to reveal contours and surface texture for enhanced reproduction. Additional views and angles were evaluated before fabricating the restoration to ensure proper contours and ceramic placement (Figure 14).
The wax was invested, burned out, pressed, and divested. The restoration was then soaked in Invex liquid for approximately 15-20 minutes, per the manufacturer’s instructions, rinsed, and blasted with aluminum oxide at 1.5-2 bars pressure. Ceramic was layered according to the detailed shade mapping previously performed, using the black and white photographs to identify locations for translucency and opacity, and the color photographs to determine chroma. The restoration was then fired in a porcelain oven. Upon removal, contouring was completed. Photographs were taken and evaluated before contour placement was outlined in greater depth (Figure 15 through Figure 17).
The final restoration was tried in and evaluated by the restorative team and patient, with both black and white and color photographs (Figure 18 through Figure 23) used for comparison. The patient was pleased with the result, and the restoration was bonded in place. Final post-operative photographs were taken (Figure 24 Figure 27) and at a later date (Figure 28 and Figure 29). Slight differences were evident between both maxillary central incisors under photographic lighting, but together achieve a sense of balance and harmony. When viewed under natural lighting, the restorations blended perfectly, surpassing the patient’s expectations.
Creating esthetic and functional restorations, particularly in the anterior region, is dependent not only upon input from both the clinician and the ceramist, but emphasis on three main areas of practice. Education, which allowed the ceramist to select IPS e.max Press as the perfect material for this case, provides the necessary background to make appropriate material and technique selection. Communication—whether photographs, models, or input directly from the patient or dentist—facilitates the fabrication process by enabling the ceramist to know exactly what is desired in terms of occlusion and esthetics. Perfecting various techniques provides ceramists with the skills necessary to create patients’ ideal restorations with ease. Therefore, it is necessary for ceramists to recognize that education, communication, and technique equally influence the design and collaborative process for planning the perfect restoration.
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About the author
Jessica Birrell, CDT
Owner, Capture Dental Arts
Saratoga Springs, UT