CERAMIC MICROLAMINATES FOR ESTHETIC RESTORATION

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1 CASE REPORT CERAMIC MICROLAMINATES FOR ESTHETIC RESTORATION Claudia Cia Worschech, DDS, MS, PhD 1 Ceramic microlaminates are an extremely thin veneer that can be fixed over natural teeth without preparation or with minimally invasive preparation. Specific surface treatments are carried out over the tooth and ceramic using materials such as acid, silane, various adhesive systems, and resin cement. These procedures increase the ceramic resistance and esthetics of the microlaminate restorations. This type of restoration is indicated to solve esthetic problems such as diastemata; inappropriate contours, size, and form of teeth; and small color alterations. Treatment with ceramic microlaminates allows maintenance of healthy dentition during the execution of planning and treatment. The use of a waxup is one important way to determine the exact amount of dental structure that needs to be removed and to define where ceramic should be added. This article demonstrates the use of ceramic microlaminates via a case report. INT J MICRODENT 2009;1: Private practice, São Paulo, Brazil. Correspondence to: Dr Claudia Cia Worschech Rua Florindo Cibin, no. 313, Americana São Paulo, Brazil CEP claudiacw@terra.com.br Ceramic microlaminates are indicated to solve esthetic problems when preservation of the natural dental structures is considered a primary goal. Therefore, proper case selection is crucial, and the clinician must have a comprehensive understanding of the patient s oral situation. A diagnostic waxup should be used to enhance the predictability of treatment by modeling the desired result prior to treatment. 1 In the past, preparations were based on geometric concepts regarding material resistance and the diameters of the burs used, and in most cases the healthy dental structure was removed without consideration of how much preparation was truly necessary to achieve a predetermined final result. Sufficient space was created to place the restorative material (eg, ceramic, metal) without preserving the natural dentition. In other words, creation of this space was the primary concern. Now, this attitude is no longer accepted. Research has been carried out to find better preventive methods to avoid caries and unnecessary dental wear. The adhesive design concept has been instrumental in the paradigm shift from the principle of extension for prevention to an ultraconservative principle for prevention to eliminate extension. The clinician should strive to preserve the integrity of the natural dentition by conserving tooth structure during preparation and by increasing the longevity of the restoration. 2 Along with superior preventive methods, the evolution of all-ceramic materials has introduced new concepts about ceramic restorations, especially about laminates. Fortunately, significant advances in materials and techniques over the last 30 years have justified the use of allceramic restorations in dentistry today. 3 The most significant of these changes occurred in 1983 when Horn 4 introduced acid-etched ceramics to create bonded porcelain veneers, which are one of the most successful restorations when bonded primarily to enamel. 5,6 With the advent of dentin adhesives in the 1990s, porcelain restorations with significantly higher bond strengths became available. 7,8 48 THE INTERNATIONAL JOURNAL OF MICRODENTISTRY

2 Figs 1 and 2 Ceramic microlaminates can be used to solve a number of esthetic problems while also preserving the healthy dentition. The other change that affected the use of all-ceramic restorations was the shift in societal attitudes concerning esthetics. 3 In the early 1980s, patients started to request more esthetic treatments along with traditional procedures, and thus cosmetic dentistry became an accepted aspect of the dental professional. Along with these changes, improvements in operative procedures have been seen due to the development of advanced technology such as digital photography, shade prescriptions, and most importantly, magnification. Most of the techniques and materials available today require a high degree of precision, and superior clarity and definition of the operative field can be achieved with high-quality lighting and magnification via the use of a microscope. This article will discuss the use of ceramic microlaminates and how this treatment can be used to solve cosmetic problems while also preserving dental health. Ceramic microlaminates require either no preparation or nontraditional preparation with rounded angles and small diastemata that are opened to establish space for the laminates. However, the success of this modality, as of all dental treatments, depends on proper treatment planning, waxup, material selection, and operator skill. CERAMIC MICROLAMINATES Ceramic microlaminates may be indicated to solve esthetic problems such as diastemata; inappropriate contours, size, and form of teeth; and small color alterations (Figs 1 and 2). The use of an additive-reductive waxup is important to determine the exact amount of dental structure that must be removed and where ceramic should be added. A diagnostic waxup enhances the predictability of treatment by modeling the desired result prior to treatment. It is crucial to correlate the waxup and the patient to avoid a result that appears optimal on the casts but does not correspond to the patient s smile and expectations. 9 Communication among the clinician, dental technician, and patient is improved with the use of a waxup and mockup, stone casts, photography, shade descriptions, and silicone guides. 10 VOLUME

3 CASE REPORT Figs 3 to 5 Preoperative views. The patient showed only cosmetic problems, with no signs of disease. Note the damaged smile line due to fracture of the incisal edges, which occurred during a football game when the patient was a child. Fig 6 The silicone guide was used to determine where it was necessary to remove tooth structure (red circles) and where ceramic should be added (yellow arrows). This clinical case demonstrates the sequence of ceramic microlaminate restoration (Figs 3 to 17). The use of a microscope improves the treatment result because it offers a precise view of the operative field through the quality and intensity of the light and the magnification process Microlaminates allow for the preservation of healthy dental structure during preparation. In some cases, no preparation is needed at all. Therefore, it is possible to modify form, contour, color, etc, without damaging the dental structures. This serves to maintain the natural resistance of the dentition without affecting longevity of the restoration. This treatment could be considered reversible since the teeth are kept intact. 50 THE INTERNATIONAL JOURNAL OF MICRODENTISTRY

4 Fig 7 A small diastema must be opened to create space for the microlaminates to be inserted and rebuild the adequate contour in the interproximal areas. Polishing disks can be used for precise removal of the dental tissue. Figs 8a to 8d The use of a microscope makes it possible to see the clinical situation in greater detail. Figs 9a and 9b To achieve superior results during nontraditional preparation, ultrasonic points can be used to prepare healthy dentition less invasively and to preserve gingival tissue in critical areas. The yellow arrow indicates the intact gingival tissue, with no bleeding evident. VOLUME

5 Fig 10 After diastemata were opened and a small amount of tooth structure was removed according to the silicone guide, nontraditional preparations were finalized using rubber points and polishing disks to achieve smooth surfaces without gaps or irregularities. Retractor cord was then used to prepare the gingival tissue and take impressions. Fig 11 Note the thinness of the ceramic microlaminates. Care must be taken during preparation, manufacturing, and cementation. Too much tension can produce cracks on the surface of the ceramic. Magnification is especially important during cementation because no cement can be left inside the gingival sulcus and the adhesive system must be applied without excess to avoid adaptation failure. Fig 12 Verification of the laminates on the cast. Fig 13 Intraoral view immediately after cementation of the microlaminates on the teeth using resin cement. c a Figs 14a to 14d (a and b) Note the initial disharmony between the ceramic microlaminate and enamel. (c) Scanning electronic microscope images make it possible to perfectly see this overcontouring (original magnification 25). (d) At 300 magnification, the thickness of the contour can be examined. b d 52 THE INTERNATIONAL JOURNAL OF MICRODENTISTRY

6 Figs 15a to 15c After polishing with rubber points, the line between the ceramic and tooth is much more harmonious. The use of a microscope enables such an excellent result. Figs 16 and 17 Final result. Note the appropriate smile line and the harmony between the teeth and lips. VOLUME

7 CONCLUSION When working with a material as thin as ceramic microlaminate, the issue of resistance soon comes to the forefront. Experimental analyses have shown that ceramic has a propensity to fracture, and cracks may be related to cement line thickness. 16 Microlaminates require that the cement line be as thin as the ceramic or less. Along with the material properties, the performance of a material depends on many factors, such as geometric preparation, adequate material selection, and correct manipulation. The minimum thickness of the laminate and the integrity of the restoration depend on the quality of the adhesion to the natural dentition. 1 The shrinkage of resin cement and the imperfect combination between the thermal expansion coefficient of the two materials involved (ceramic and resin cement) and the tooth may lead to cracks. This problem may be minimized through soft preparations (without defined angles) and with sufficient thicknesses of cement and ceramic. Further, ceramic laminates that present cracks can be kept in place, since the adhesion between ceramic and tooth has been shown to be reliable. 17 This way, the dental tissue continues to be preserved, and if the restoration fails, it would be possible to replace it with another laminate. While all treatments carry risks, ceramic microlaminates represent one conservative method for solving esthetic problems and preserving dental health. The use of a microscope in conjunction with ceramic microlaminates provides an accurate view of the operative field and precise analysis of the preparation, allowing for the production of smooth surfaces without gaps or incorrect contours. This procedure provides excellent results when proper care is taken by the clinician before, during, and after treatment. 54 THE INTERNATIONAL JOURNAL OF MICRODENTISTRY

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