March 2008, Volume 4, Issue 3
Published by AEGIS Communications
Direct Resin Realignment Alternatives to Orthodontic Treatment
Gerald E. Denehy, DDS, MS
The emphasis on esthetics in our current culture has resulted in patients’ increasing interest in options for achieving an optimal appearance. The orthodontic treatment of malaligned teeth has long been an established standard for the solution of both esthetics and functional dentition problems. Although orthodontic treatment is common in the current affluent young dental patient, there are many older patients who have malalignment problems and have never had orthodontic treatment. These patients may or may not have functional problems, but they usually come to the dentist because of a need to improve the esthetics of their malposed anterior teeth.
Complete or limited orthodontics certainly should be given first consideration in these cases. However, many patients decline orthodontic treatment for a variety of reasons. For some patients, the treatment may be too expensive or take too much time. Many older patients do not like the inconvenience of wearing braces and the discipline involved with proper compliance with the treatment. It is usually necessary for adults to require long-term or permanent stabilization for teeth treated with orthodontics or relapse will occur. Occasionally, periodontal problems may not allow the proper movement and stability of the teeth. Fortunately, patients who choose not to undergo orthodontics do have other restorative options.
Malposed anterior teeth can often be esthetically treated through contour modification with a restorative material. Through creative optical illusions, teeth may be reshaped and additions made to create the appearance of proper arch alignment. Treatment of these cases is on an individual basis, and the ultimate success may relate to the operator’s skill and the severity of the malposition of the tooth. Patients must realize that visual realignment through restorative procedures will not correct functional problems. If an attempt is made to provide a visual realignment through restoration, it is crucial that conservation be maintained in tooth structure removal, periodontal health not be compromised in the restored teeth, and no incisal or occlusal problems be created.
The dentist must choose between indirect or direct procedures when changing the contour of tooth structure with a restoration. If the anterior tooth structure is intact, the concept of crowning teeth does not fit into the conservative category. Devitalization and total realigning through the use of a full-coverage restoration may change the crown-to-root angulation, resulting in possible periodontal problems. Although bonded porcelain veneers are often recommended to treat malpositioned teeth, many times the tooth structure removal that is necessary to place veneers correctly, without creating undercuts in the preparations, will be excessive. The cost of bonded porcelain is often out of the range of many dental patients, preventing them from accessing treatment.
Direct composite resin materials can present an ideal option for the treatment of overlapped or malposed anterior teeth. Through judicious tooth structure removal, contours may be changed easily and without concern of undercut areas. Material may be added to the lingual as well as the facial and incisal surfaces, resulting in a balance of marginal ridges, line angles, and embrasures. In many cases, the amount of tooth structure removed can be limited to enamel, resulting in an improvement of retention and longevity.
The use of whitening procedures should be considered when planning tooth modification with a direct resin restoration. The dentin shade of bleached teeth is very close in chroma to the external tooth surface, and minor reduction of the enamel will not result in darkening from the underlying dentin.
Direct resin realignment procedures challenge the artistic abilities of the dentist. Incisal thickening and proximal recontouring and reshaping must all be done with the ability to provide an optical illusion. Although there are many cases that may be esthetically treated with direct resins, the dentist should be aware of the fact that some cases should not be attempted. Severe overlapping or excessive angulation necessitates excessive tooth removal and should only be treated orthodontically.
Before restoring the teeth, it is crucial that the dentist be able to envision the end result. Often this is best facilitated by taking a study model and waxing in the planned additions to determine if the desired esthetics are possible. It is important that the central incisors be symmetrical and properly aligned when planning the treatment. The location of the most facially positioned tooth in the arch will determine the arch curvature position. If the tooth is too far facial, the result will be unesthetic. The facial lingual thickness of the incisal edge of maxillary anterior teeth may be increased significantly as long as it is angled toward the palate in all areas lingual to the normal arch alignment. This angulation prevents the viewer from seeing the true thickness of the restored incisal edge. As mandibular anterior teeth are viewed from the incisal, edge thickening must be done judiciously to prevent it from being apparent.
Any quality direct composite resin system or combination of systems may be used to restore malpositioned anterior teeth. These systems can include microfilled resins, microhybrid resins, and nanofilled resins. As many of the additions involve minor modifications of the existing tooth structure, enamel or body shades of resin are often used. If the restoration involves addition beyond normal enamel thickness, then it should be backed by a dentin opacity material. Enamel-effects shades, such as translucent and milky-white, may be used for appropriate characterization.
Case 1 is a minor overlap case involving all maxillary incisors (Figure 1 and Figure 2). Reshaping of the enamel was achieved by reducing the facial proximal line angles of teeth Nos. 7, 9, and 10 to eliminate the overlap (Figure 3). Realignment was achieved by resin additions to the mesial-lingual-incisal surfaces of all three teeth, with facial additions to tooth No. 8 and the distal of tooth No. 9 (Figure 4 and Figure 5). Materials used included a microfilled resin (Durafill® VS, Heraeus Kulzer, Armonk, NY) for enamel replacement and a dentin shade of a hybrid (Herculite XRV, Kerr Corporation, Orange, CA) for backing.
Case 2 is a patient with teeth Nos. 8 and 9 in strong lingual version with a mesiofacial rotation and overlap involving teeth Nos. 6, 7, and 10 (Figure 6 through Figure 8). Reduction of the teeth involved primarily enamel and included the distal-proximal surfaces of the maxillary central incisors and the mesio-facial surfaces of teeth Nos. 7 and 10 (Figure 9 and Figure 10). An attempt was made to equalize the width and provide proper alignment of the central incisors, and to minimize overlap. Restoration was achieved with the body shade of a nanofilled resin (Filtek Supreme, 3M ESPE, St. Paul, MN) by thickening of the incisal edges of teeth Nos. 8 and 9 and adding to the distal-facial of tooth No. 7 and to the mesial-lingual of teeth Nos. 6, 7, and 10 (Figure 11 through Figure 13). The restored incisal edges were angled palatally to provide the optical illusion of proper thickness.
When selecting an esthetic treatment for malpositioned anterior teeth where full orthodontic treatment is not an option, the direct composite resin systems should be given consideration. Excellent long-term esthetics, affordability, and—most important—conservation of tooth structure can often make this the best option for the patient. Table 1 summarizes the options for treating malpositioned anterior teeth without using full orthodontics.
About the Author
Gerald E. Denehy, DDS, MS
Dr. Bob and Jerilee Williams
Professor in Restorative Dentistry
Professor and Chair
Department of Operative Dentistry
The University of Iowa College of Dentistry
Iowa City, Iowa