Recreating an Aesthetic Smile: Multidisciplinary and Metal-free Approach Using CAD/CAM Technology
Giancomo Fabbri, DDS
Prosthetic rehabilitation of anterior teeth is one of the most demanding tasks facing clinicians. Often, teeth not only require prosthetic rehabilitation using crowns, bridges, or veneers; periodontal therapy may also be required to address aesthetic, biological, and prosthetic concerns. The gingival tissue has a relevant role in determining a satisfying result of the treatment. A healthy gingiva that displays appropriate contours is a key factor to achieving an optimal aesthetic result.1
Restorative and periodontal elements such as the incisal length, plane, profile, and display, in conjunction with tooth shape and color, tooth-to-tooth proportions, gingival architecture, and gingival display should be considered in the creation of an aesthetic smile.2 A harmonic combination between the gingival tissues and the dental restoration will result in improved aesthetics. Gingival health and color, interdental closure, gingival line zenith, gingival level equilibrium, and interdental contact levels are fundamental criteria to evaluate oral aesthetics.3-5 To achieve ideal implant aesthetics, correct implant position and ideal hard and soft tissue volume around an implant can guarantee a stable functional and aesthetic result.6
Contemporary aesthetic materials allow clinicians to deliver extraordinary results, particularly when the soft tissues are healthy.7,8 A team approach that includes the clinician, laboratory technician, and the patient is required to achieve desired results when a multidisciplinary approach is indicated.
A 36-year-old female patient presented with aesthetic concerns and dissatisfaction with her existing smile (Figures 1-2-3). Although orthodontic therapy had been performed two years prior to presentation, the patient refused additional orthodontic therapy. Diagnostic evaluation was performed and no intraoral pathology was observed. Tooth #24 was restored with a temporary acrylic crown.
The patient reported no parafunctional habits. A 3-mm overbite and 1.5-mm overjet were present. Maximum intercuspation and centric occlusion were not coincident. The bilateral partial group function was observed on lateral excursions with nonworking interferences. Posterior interferences were present during protrusion. Regardless, the patient was comfortable with the present vertical dimension and had no muscular discomfort or clicking in the temporomandibular joints.
The patient presented with a high smile line and excess gingival display greater than 3 mm when smiling. The incisal edge line of the maxillary anterior teeth was in harmony with the mandibular lip line. Diastemata were present between the natural teeth and tooth #12 was missing. The gingival line zenith was not in an ideal position, and the gingival level of tooth #13 was apically positioned. Tooth #22 was previously treated with a composite restoration to correct the shape. The patient’s tooth proportion, shape, dimension, and axis were inadequate. Although the ideal height-to-width ratio of the maxillary central incisors is approximately 80%,9 the patient presented with a 98% ratio. The anterior maxillary crowns were short and small during smile and speech, and excessive display of the mandibular dentition was also evident. The maxillary midline was not coincident with mid-facial vertical plane; it was moved approximately 3 mm to the left. Occlusal and horizontal planes were parallel.
A vestibular crown-lengthening procedure was planned to establish gingival symmetry, reduce excessive gingival display, and provide a proper height-to-width ratio for the anterior teeth.
Professional oral hygiene, reinforcement of motivation, and oral hygiene instructions were provided. The definitive treatment plan was finalized at the re-evaluation, following assessment of the patient’s compliance and oral hygiene. The following treatment plan was formulated:
- Aesthetic vestibular crown lengthening on teeth #6(13) to #11(23) with simultaneous implant placement in region #7(12).
- Placement of porcelain laminate veneers on teeth #6, #8(11), #9(21), #10(22), and #11, and single crowns on teeth #7 and #12(24) fabricated using CAD/CAM technology.
- Occlusal stabilization via elimination of interferences while maintaining the current vertical dimension.
- Prescription of an occlusal nightguard.
A direct mock-up was created from the diagnostic wax-up and used to visualize the anticipated result prior to treatment initiation. Periodontal surgery was performed with a surgical template to ensure proper gingival height in the aesthetic zone. Bone architecture was defined for aesthetics reasons (Figure 4). At the same time, an implant was placed in region #7. Although a tapered implant was used to minimize the risk of damaging the roots of adjacent teeth, the vestibular bone crest was fractured during implant placement (Figure 5).
The fragment was repositioned, and a bovine-derivate graft was placed. The graft was covered with a resorbable barrier that was stabilized with a mini-nail in titanium. In region #7, the flap was sutured with horizontal mattress sutures until the incision was completely sealed. No provisional restoration was provided. The patient was instructed to use chlorhexidine gel for the following two weeks and to avoid brushing and trauma at the surgical area. The sutures were removed two weeks later. After six months, a soft tissue graft was performed during the re-entry operation (Figure 6). Nine months following crown lengthening, tissue healing was complete and the teeth were prepared for restoration with alumina laminates (Figures 7 and 8).10 A single alumina crown was fabricated to restore tooth #12. In order to modify the shape and contour of the patient’s dentition, the margins were placed slightly subgingival.11,12 A polyether impression was obtained prior to provisionalization (Figure 8). The zirconia abutment and alumina crown were subsequently fabricated in the laboratory using CAD/CAM technologies (Figures 9 and 10).
A zirconia abutment was positioned and the restorations were cemented. Because acid etching techniques are not functional for alumina restorations, the laminate veneers and crowns were sand-blasted. The surfaces were then cleaned with alcohol, and a silane agent was applied and blown dry on the veneer and crown restorations. Finally, a bonding agent was applied to on the inner surface of the laminate veneers; no bonding agent was applied on the inner surface of the crowns. The crowns and laminate veneers were then cemented. Excess composite was removed. The gingival tissues were covered with glycerin gel, and the resin composite was cured from each side for 60 seconds. Occlusion was then evaluated (Figures 9-10-11-12-13-14-15).13
In recent years, research has focused on developing new ceramics with improved aesthetic and mechanical characteristics.14 In the case described, no clinical and radiographic complications were observed twelve months following placement, and the restorations were functioning normally. In order to determine predictability and efficacy, however, this technique must be tested in properly designed randomized clinical trials with a sufficient number of patients.
The aesthetic rehabilitation of a patient with a functionally compromised dentition frequently involves a multidisciplinary approach. Proper performance of different phases of the treatment plan and the use of appropriate materials guarantee aesthetic and functional success. This clinical case demonstrates a successful multidisciplinary approach to recreate an aesthetic smile in a young patient with functionally and aesthetically compromised anterior maxillary dentition.
*Private practice, Cattolica, Italy.
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