Introduction
The unesthetic appearance of anterior teeth due to diastema is a common clinical finding. When such a patient comes to the dental surgeon with the expectation of the earliest possible correction, the role of digital smile designing in achieving predictable esthetic outcome is crucial.[1] In this case report, a 21-year-old patient having diastema and incisal notching was treated with porcelain laminate veneers using combination of digital and analog workflow.
Case Report
The patient reported a chief complaint of the unesthetic appearance due to spacing of front teeth since childhood. The patient was an electrician by profession and gave a history of holding wires and screws between his upper and lower front teeth. On intraoral examination, notching and abrasion of incisal edges on all incisors were observed. The cuspal tip of canines also showed wear. There was diastema in maxillary and mandibular anterior teeth. A group function occlusion was evident on a protrusive and laterotrusive excursion. Furthermore, on the protrusion, there was diminished contact between the incisal edges of maxillary and mandibular central incisors [Figure 1]. The canines and first molars were in Angle’s Class I relationship. With the initial finding, the patient was advised orthodontic treatment for diastema closure. However, he was unwilling for orthodontic treatment and wanted early results. Hence, a prosthetic plan was formulated to treat diastema and incisal notching at the same time. Digital smile designing and virtual mock-up were done on “Exocad software” using patient’s “smiling” and “lip retracted” photographs to visualize the expected outcome of treatment. The appearance of a smile was shown to the patient for consent. It was decided to restore the patient with porcelain laminate veneers from right to left canines involving the incisal edge so that the incisor notches could also be treated. Apart from porcelain laminate veneer, the alternate plan could be rehabilitation with full-coverage restoration which could have required extensive tooth preparation and hence was excluded. This digital mock-up was superimposed on the scanned cast of the maxillary and mandibular arches to get the 3D-printed mock-up [Figure 2a-d]. The clinical steps and laboratory steps involved in this are illustrated in Figure 3. Postoperatively, the smile of the patient was enhanced. He was highly satisfied with the esthetic outcome [Figure 2e].
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Figure 1: Maximum intercuspation and protrusive excursion
Figure 2: (a) Digital smile designing, (b) Superimposition of smiling and retracted lip photo, (c) Digital mock-up, (d) Preoperative patient smiling photograph, and (e) Postoperative patient smiling photograph
Figure 3: Analog and digital workflow
Discussion
Porcelain laminate veneers are generally indicated for discoloration secondary to tetracycline stains, fluorosis, closure of diastema, and mild rotation of teeth (when the patient is unwilling for orthodontic treatment). It is contraindicated in patients with high caries index, poor oral hygiene, excessive staining, deep bite, severe orthodontic problems, parafunctional habits, etc. The porcelain laminate veneers have a high survivability rate.[1]
Digital smile designing is an innovative tool in esthetic dentistry which allows us to foresee the outcome of treatment to the satisfaction of patients.[2] The prime requirements are patients smiling and cheek retracted photographs from the same distance and angle. These images provide exposure of teeth hidden behind the lip and then designing the smile on Exocad software. Various forms of teeth are available in the virtual library of the software, and the best-matched form is applied to the designed smile. This software aligns the smile as per golden proportion which needs to be adjusted by taking into account the patient’s requirement. After this, confirmation of smile from the patient is taken. Correlating it with the 3D scans of the patient’s maxillary and mandibular casts by comparing the dimension of the tooth, the gingival zenith, etc., will provide data for 3D printing of virtual mock-up. Designing the patient’s smile by using the patient’s photographs and then merging these data to the virtual cast to get 3D-printed mock-up help to achieve a predictable, natural, and life-like restoration.
Alhammadi et al. described the soft-tissue facial profile measurements by various tomographic methods which were more accurate compared to the standardized digital photographs. The use of wrapped CBCT images from nonstandardized random frontal photographs is reliable and can be used for the purpose of analyzing the soft-tissue facial profile measurements. The great capabilities of this technique, combined with digital and data management and reconstruction software, allow surprising results.[3]
There are various techniques described in literature ranging from “no preparation” to “invasive preparation.” In the present case, we used a semi-invasive technique as preservation of enamel is very crucial for this type of bonded restoration which very strongly adheres to enamel.[4] The longevity of ceramic laminate veneers in terms of serviceability and quality of the restoration is significantly better compared to indirect composite laminate.[5] The incisal preparation design is one of the crucial factors for the longevity of the prosthesis. A butt joint has shown longer durability.[6] The same was incorporated in the present case. It took care of incisal notching in the patient.
Selecting the appropriate material for laminate is also highly crucial to achieve esthetics, durability as well as longevity of the restoration. Glass ceramics are the most esthetic and match the natural translucency of tooth, thereby providing a life-like appearance.[7] In this case, we have used lithium disilicate-modified glass-ceramic with enhanced mechanical properties such as strength, toughness, and yield strength.
Correct anterior guidance is the key to successful rehabilitation. The anterior teeth protect the posterior teeth by disoccluding them in an eccentric position. The posterior teeth protect the anterior by receiving most of the forces of closure in a centric position.[8] The same was replicated in this case.
Another important aspect of veneering is the preparation technique and the correct bonding procedures. Initially, the intaglio surface of the laminate veneers is sandblasted to create micro-irregularities and then treated with 9% hydrofluoric acid. Treating intaglio surface of porcelain veneers with hydrofluoric acid tends to selectively dissolve the glassy matrix resulting in microscopically porous, high-energy, and micro-retentive surface. This principle is similar to what happens to the enamel surface after etching with phosphoric acid. The next is the application of a silane coupling agent to the intaglio surface of the laminate veneer. Silane coupling agents are compounds whose molecules contain a functional group that bonds with both organic and inorganic material. After acid etching of prepared tooth surface with phosphoric acid, primer was applied and restoration was bonded with dual-cure resin cement (Ivoclar Variolink). Dual-cure resin cement is available in a variety of shades such as white, yellow, and translucent.[9] A translucent shade was used in the present case as there was no discoloration.
Summary and Conclusion
Veneering is a highly technique-sensitive procedure. The clinician must possess in-depth knowledge of the technique and the material used in veneering. For achieving a predictable smile, digital smile designing is a helpful tool. It provides a virtual diagnostic mock-up. Careful correction and duplication of anterior guidance aid in the long-term success and functional harmony of the prosthesis. Appropriate selection of material for rehabilitation is paramount in assuring durability and longevity to the restoration. With the advancement in adhesive techniques and material, the laminate veneer becomes part of the tooth, thus imparting naturality to the final restoration. The present case has been followed for 2 years without any complication of debonding, fracture, or discoloration of prosthesis. However, long-term success and functional harmony depend on case to case basis.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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