Aesthetic Management of Congenitally Missing Lateral Incisors Using a Semi-Direct Restorative Approach
Newton Fahl, Jr., DDS, MS
A 24-year-old female patient presented with edentulous
spaces caused by congenital agenesis of the lateral incisors. Previous
orthodontic treatment had been completed, and the appliance had been removed.
In order to maintain the correct position of the tissues and prevent a relapse
from occurring, a removable prosthesis was worn (Figure 1). Several treatment
modalities were presented to the patient, who required a minimally invasive yet
aesthetic comprehensive restoration. Rehabilitation with bilateral
single-implant prostheses was declined due the invasive nature of the surgical
procedure and treatment duration; adjunct vital bleaching was also declined. A
proposal for buildup with multiple layers of composite resin and stabilization
with a polyethylene ribbon was presented to the patient, who accepted this
conservative modality as a result of the reduced treatment duration.
The gingival tissue of the patient was examined by the
clinician in order to verify that an adequate quantity of keratinized tissue
existed in the edentulous sites. Upon soft tissue evaluation, it was evident
that the anterior segment of the patient required crown lengthening. In
addition, the maxillary central incisors exhibited an unsatisfactory length
to width ratio (Figure 2). In order to exhibit harmonious proportion to the
adjacent dentition, the morphology of the teeth required correction. The
gingival architecture had to be established so that the level of the canines
was equal to that of the central incisors. Since the presence of canting would
have compromised the aesthetic result, the clinician determined that electrosurgery
had to be performed to correct the existing soft tissue silhouette.
Once an anesthetic was administered, sounding of the bone
crest was performed in order to determine if proper biological width was
present. Measurements indicated that gingivoplasty would suffice to achieve the
permanent corrective result (Figure 3).
Three weeks postoperatively, a degree of relapse had
occurred at the site of the central incisors. A slight diastema was evident
between teeth #8 and #9 (Figure 4). Using the original prosthesis, the anatomy
of the pontic teeth was restored by apposition. In order to restore the
cervical and incisal length of the teeth, a fine layer of microfilled
composite resin was applied to the mesial and facial aspects of the maxillary
central incisors. The gingival architecture mimicked the natural tissue by the
same procedure, maintaining the level of the gingival zenith of the lateral
incisors short of the level of the maxillary central incisors, and positioned
slightly off their long axis.
The patient returned to the orthodontist for the
reestablishment of proper facial alignment in order to address the minor
relapse that had occurred. The patient wore the appliance for a 7-day duration
(Figure 5). Following the completion of the orthodontic procedure, gingival
contouring was performed for a second time through electrosurgery to mimic the
design established by the pontics. The architectural design of the prosthetic
abutment of the appliance dictated the morphology of the tissue. Seated under
compression, the pontic applied pressure to the soft tissues that developed the
innate shape of the natural dentition. Proper anatomy and gingival contour of
the ovate pontic restoration were reestablished.
The orthodontic appliance was removed by the clinician.
Examination 4 weeks postoperatively revealed the proper pontic design and
architecture of the sound gingival tissue (Figures 6 and 7). A chlorhexidine
rinse was prescribed for the patient to prevent bacterial contamination of the
site. The treatment site was subsequently prepared for the recording of
impressions. This was completed immediately upon removal of the appliance in
order to establish the position of the tissue. Any delay in this process could
have resulted in tissue relapse. Once the orthodontic appliance and the
transitional prosthesis had been removed, the proper gingival scalloping and
symmetry of the interdental papillae were evident (Figure 8).
The framework for the definitive restoration was fabricated
from a condensable composite material that is generally utilized in the
posterior region. The physical properties of the material permitted the
development of a durable restoration. A polyethylene ribbon was used to provide
reinforcement to the composite framework. Lingual preparation was accomplished
according to the traditional preparation guidelines to achieve improved
retention and stability of the prosthesis.
The connection sites on the models were fabricated to
encompass the largest surface area possible on the palatal aspects. Proper
gingival and incisal embrasure forms were established to allow subsequent
buildup with composite materials. This permitted the utilization of various
hygiene devices (ie, floss and interproximal brushes) to regulate the oral
health of the patient.
The framework was subsequently tried in to verify the fit of
the intended restoration (Figures 9 and 10). The clinician ensured that proper
proximal contacts were maintained by the removable appliance in order to
prevent any discrepancies upon final seating. Pontic design was verified by the
clinician, to ensure the long-term stability of the treatment, and symmetry was
established between the two maxillary anterior quadrants.
Several factors that related to the proportion of the
restoration were then addressed. The incisal edge of the framework was
fabricated 1.0 mm to 1.5 mm above the anticipated edge of the definitive restoration
to allow sufficient space for the intrinsic composite buildup (Figure 11).
This allowed the clinician to depict the mamelon morphology and polychromatic
variations imparted by the use of multiple composite resins, tints, and
During chairside fabrication, the pontic was cut
approximately 0.5 mm short of the free gingival margin in order to facilitate
the development of a composite restoration that appeared to emerge from the
gingival tissue (Figure 12). While a composite resin must be selected to match
the shade value, hue, and chroma of the adjacent central teeth, the clinician
selected a composite resin that was 1 chroma higher than that of the adjacent
tooth for this presentation. This imparted a transitional appearance on the
maxillary arch, which was altered slightly from the central incisors, the
built-up lateral incisors, and the canines.
The mamelon buildup was completed utilizing a hybrid composite
resin. The translucency and opalescence of the teeth were rendered with a
microhybrid composite resin. In order to replicate the maverick colors and to
provide additional polychromatic effects, a series of buildups was completed
using tints and opaquers (Figure 13).
The pontics were heat-tempered under approximately 85 psi at
120° C for a 10-minute period. The heat-tempering process enhanced the physical
properties of the framework and the composite buildup. A definitive finish and
polish was performed to achieve a luster that would be indistinguishable from
the natural dentition (Figure 14).
In order to facilitate cementation, the pontic wings and the
palatal aspects of the maxillary canines and central incisors were sandblasted
with 50 µm aluminum oxide. Phosphoric acid was applied to cleanse the pontic
wings, which were subsequently rinsed and dried. Since the condensable
composite resin was a hybrid material, silane was also applied to the wings.
The central incisors were also prepared with phosphoric acid. A single
component adhesive was applied to the pontic wings and the abutment teeth, and
the pontics were bonded into place with a light-cured cement (Figures 15 and 16).
The pontics were initially spot-cured with a 4-mm turbo light
guide to allow for the partial removal of excess cement between and beneath the
pontic and around the abutment teeth. Glycerine was applied over the entire
restoration. The wings and the facial aspects of the pontics were exposed to a
13-mm light guide for an additional 60 seconds.
The fidelity of the material, color, and texture of the
pontic restorations and the composite buildup were observed upon completion of
the technique (Figure 17). The correct morphology and condition of the
interdental papillae was also evident (Figure 18). The duration of the entire
treatment from the initiation of the electrosurgery to the completed
restoration was only 2 months, which was significantly shorter than more
invasive alternative restorative procedures (ie, implant therapy or a
conventional 3-unit bridge).
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