Adhesive Composite Inlays for the Restoration of Cracked Posterior Teeth Associated with a Tongue Bar
A Case Report
Deborah S. Cobb, DDS, MS
A 23-year-old male patient presented with pain associated
with mastication. Examination of the soft tissue revealed a perforation in the
midline of the anterior portion of the tongue. Upon further questioning, it was
ascertained that the patient had undergone tongue piercing approximately 1 year
previously, and wore a barbell-shaped tongue bar that had been removed prior to
the examination. The patient also admitted to a parafunctional habit of biting
on the bar. Upon request, the patient produced a stainless steel bar, 20 mm in
length and 2 mm in diameter, that had a 6-mm diameter ball affixed at each end.
The tongue bar was inserted (Figure 1) and the patient demonstrated the
position of the metal ball during parafunction, which was between the first
premolars (Figure 2). Cracked or "craze" lines were observed
mesiodistally on both maxillary first premolars (Figure 3). The first premolars
and adjacent teeth were evaluated with an electric pulp tester and CO2
ice. All teeth responded within normal limits to the electric pulp testing
device. A slight increase in response to CO2 ice was elicited by the
first premolars. These teeth were also sensitive to biting on a fracture
detector. Radiographs exhibited no periapical pathology. A diagnosis of
reversible pulpitis associated with cracked teeth was resolved. The
parafunctional habit was determined to be responsible for the crack lines and
symptomology that occurred.
The treatment plan for the patient required the elimination
of the tongue bar and the associated oral habit; conservative restoration of
the fractured teeth was planned. In order to maximize tooth preservation,
eliminate symptoms associated with the fractured tooth, and prevent the
propagation of additional fracture, bonded indirect composite resin inlays were
selected as the restoration of choice.
The tongue bar was not worn for 2 weeks, at which time the
patient was recalled. Upon examination, the tissue perforation appeared to be
closed. The preoperative shade of the dentition was assessed with a shade guide
and determined to be A-2. The patient was anesthetized and a rubber dam was
placed to provide proper isolation.
A conservative cavity design was utilized, exhibiting
approximately 10 degree divergence, rounded internal line angles, and 90 degree
cavosurface margins. A series of burs from an inlay/onlay kit were used to
complete the mesiodistal cavity preparations for posterior indirect
tooth-colored restorations. The occlusal portion of each tooth was prepared
with the small tapered diamond bur. Using the thin tapered diamond, proximal
walls were extended to clear contact with the adjacent tooth. The end-cutting
diamond was used to smooth and flatten pulpal and gingival floors and establish
a butt-joint margin in the proximal box without damaging the adjacent tooth
structure. All walls of the preparation were smoothed with the carbide
finishing bur. Since no decay or preexisting restorations were present in the
teeth, a preparation with a pulpal floor depth of 1.5 mm and an isthmus width
of 2 mm was utilized to provide adequate strength for the indirect restorative
material while maintaining the integrity of the tooth (Figure 5). A decision
was made not to utilize an onlay for the cusps, but instead to rely on the
reinforcement provided by the adhesive restoration. The use of bonded resin
inlays as a treatment modality had previously been used successfully by the authors
for conservative restoration of fractured teeth.
Using a triple tray technique and a polyvinylsiloxane
material, an accurate impression was made of the finished preparations. A
composite temporary material was utilized to fabricate a provisional
restoration, since only short-term temporization was required. This resin
material was placed directly in the cavity preparation and contoured to provide
contact with the adjacent dentition. Following polymerization with a visible
curing light for 20 seconds, the material achieved a consistency of hard soap
and was easily contoured into occlusion using a cleoid-discoid instrument. The
provisional restoration provides sufficient short-term seal and resistance to
dislodgment. If the cusps are capped, however, or long-term temporization is
required, consideration should be given to an indirectly fabricated resin
temporary material, which provides greater strength and durability. The patient
was dismissed with oral hygiene instructions and cautioned to avoid chewing
hard or sticky foods.
Indirect microfilled resin inlays were fabricated by a
commercial laboratory. Upon return for the cementation procedure, the patient
was anesthetized and the field was isolated with a rubber dam. The provisional
restoration was easily removed by inserting an explorer at the gingival margin
and lifting occlusally. The cavity preparations were examined for residual
material and thoroughly cleaned with a prophy brush and pumice slurry. Each
inlay was tried in to assess fit and marginal integrity (Figure 5)
Generally, if the inlay restoration does not demonstrate
proper fit, the contacts can be checked with floss and modified as necessary.
Contacts can easily be adjusted using a 1/2-inch polishing disk or flame
finishing bur and polished with rubber points. Once proper interproximal
contact is established, internal irregularities or external flash at the
cavosurface margins may still prevent complete seating of the restoration.
Since minor irregularities in the axial pulpal and axial gingival line angles
often prevent proper seating, they must be examined first and adjusted
accordingly. If internal adjustment is necessary, a 1/4-inch round bur may be
used to provide proper fit. The cavosurface margins should be examined on the
die and intraorally for ancillary material. Areas of excess resin can be
indicated lightly with pencil and removed using a 3/8-inch red disk.
Once proper fit and margination were established, the inlay
restorations were prepared for cementation. A dual-curing resin luting agent
was utilized in combination with an adhesive system to cement the inlays. This
resin cement has desirable characteristics that provide advantages over current
luting agents. The dual-curing resin cement is a highly filled (72% wt) small
particle hybrid resin with homogenous distribution of particles that averages
0.7 µm. This cement is available in a convenient capsule form that ensures
consistent powder/liquid ratios and reliable mixing of components without the
incorporation of air. The tip on the capsule provides an easy means of applying
the cement to the cavity preparation and the restoration.
An adhesive-coated applicator was attached to each inlay to
facilitate the handling and placement procedures. While the adhesive on the
applicator holds the inlay securely prior to placement in the cavity
preparation, the instrument may be passively removed once the inlay is seated.
In order to enhance bonding, the internal surface of each inlay was sandblasted
for 3 to 4 seconds using 50-µm alumina oxide particles in a microetcher (Figure 6). The bonding surface of each inlay was subsequently cleaned and treated with
37% phosphoric acid for 15 seconds (Figure 7), rinsed thoroughly, and dried. A
surface softening and wetting agent was applied to the internal surface for 30
seconds and air dried (Figure 8). A thin coat of adhesive resin was then
applied to the surface and permitted to dry.
A Tofflemire matrix band was placed around the prepared
tooth to protect the adjacent teeth from contact with the adhesive materials.
The preparation was etched with 37% phosphoric acid etchant gel for 20 seconds
(Figure 9), rinsed thoroughly for 15 seconds, and left moist. The adhesive
primer was applied to the entire cavity preparation for 20 seconds using a
scrubbing motion (Figure 10) and dried with a gentle air stream. The adhesive
resin was then applied to the preparation, scrubbed for 20 seconds, and thinned
gently with air.
Prior to cementation of the inlay, the matrix was removed.
The dual-cure resin cement is available in a variety of shades keyed to the
Vita shade guide; however, one particular shade is often selected as a
universal material since it blends well in most clinical applications. The
resin cement capsule was tapped firmly on the counter, placed in an activator,
and utilized by depressing the lever firmly for 2 to 3 seconds. The activated
capsule was mechanically triturated for 10 seconds at 4,300 cpm and placed in
the application device; the injection tip was subsequently positioned for
proper dispensing. The cement was applied to cover the bonding surface of the
inlay (Figure 11), and a thin layer was injected to line the cavity
preparation. This was accomplished to ensure adequate coverage with cement and
to prevent voids at the tooth/restorative interface. Using the applicator tip
for placement and positioning, the inlay restoration was seated with moderate
pressure (Figure 12). The applicator tip was easily removed from the inlay by
applying counterpressure to the restoration with a ball burnisher while using a
quick pulling motion on the applicator. This process ensures the removal of all
residue from the surface of the inlay.
While holding the inlay in place with a ball burnisher,
excess cement was removed from the cavosurface margins using a brush; care was
taken not to pull cement from the interface (Figure 13). Pressure was
maintained while dental floss was passed in a downward motion interproximally
and pulled out buccally to clean excess cement from contacts, embrasures, and
the gingival margin (Figure 14). The inlay was then polymerized for 60 seconds
each from the occlusal, buccal, and lingual aspects using a visible curing
light in the continuous mode (Figure 15).
A #12 scalpel blade was used interproximally to remove
gingival flash and a 1/2-inch contouring disk was utilized to remove excess
cement and refine proximal margins (Figure 16). Occlusal cavosurface margins
were adjusted and flash was removed with a bullet-shaped finishing bur (Figure 17).
Prior to removal of the rubber dam, a composite surface
sealer was utilized to enhance marginal integrity and reduce cement wear. The
tooth was isolated from adjacent teeth using mylar strips and 37% phosphoric
acid etchant was applied to the cavosurface margins for 15 seconds (Figure 18).
Once the tooth was thoroughly rinsed and dried, resin sealer was applied to all
margins (Figure 19). The sealer was polymerized 20 seconds each from the
occlusal, buccal, and lingual aspects.
Following the removal of the rubber dam, occlusion was
verified with blue articulating paper (Figure 20). Any necessary adjustments
were made using a round finishing bur, and the inlay was polished with
silicon-dioxide-impregnated rubber polishing points. Superficial scratches were
initially removed by polishing with the medium-grit point using intermittent
water spray, and the definitive polish was achieved by the use of the
extra-fine point without water (Figure 21). The patient received homecare
instruction and was cautioned to avoid future use of a tongue bar or biting
other hard objects. Upon reexamination 1 week subsequently, the patient
reported no sensitivity to cold or mastication and that he had regained
function. The patient was recalled for a 1-month evaluation for continued
clinical study, at which time the restoration demonstrated superior results in
all categories (Figure 22). The symptoms of reversible pulpitis had not
returned. The patient has discontinued the use of the tongue bar.
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