58
|
CERECDOCTORS.COM
|
QUARTER 1
|
2016
C A S E S T U D Y
| | |
B Y D A R I N O ’ B RYA N , D . D . S .
computer-aided design/computer-aided manufacturing (cad/cam) in dentistry
has enabled dentists to assume
more control over the restorative process and streamline the workflow involved with delivering high-quality and esthetic indi-
rect restorations to patients. As a result, many restorations that previously took weeks to plan, design, fabricate and deliver can
now be completed in a matter of hours and in the same day because digital processes have replaced time-consuming procedures tradi-
tionally performed by hand (e.g., taking impressions, pouring models, hand-pressing or layering ceramic restorations).
1
Ensuring Proper Isolation and
Thorough Excess-cement Removal
During CAD/CAM Veneer Procedures
However, although technology has made these processes more
efficientandpredictable,thereremainessentialclinicalprocedures
that can be technique sensitive and, if not performed diligently,
can cause delays and frustrations to what should be a streamlined
and predictable appointment. These processes include ensuring
adequate isolation during tooth preparation, digital impression
taking and adhesive cementation, as well as adhering to adhesive
protocol, and thoroughly cleaning and removing excess cement
from restorations and around gingival margins.
2,3
When taking impressions — even if they are obtained using
digital intraoral scanning devices — the preparation margins must
be clearly visible.
4
A cost-effective and user-friendly latex-free
option for effectively retracting the lips and cheeks during dental
treatment (e.g., OptraGate) is ideal for CAD/CAM cases and digital
impression taking because it enables unimpeded, even retraction
of the lips and cheeks across a large area. Likewise, it enables an
unobstructed view when photographing the teeth for shade-taking
purposes —whether using a digital camera or an intraoral scanner.
It is important to note that because intraoral scanners cannot
accurately and completely acquire images of what they cannot
detect, complete and thorough retraction and isolation are impor-
tant for digital impression taking. Such retraction is essential
because the presence of blood, saliva and debris affect the quality
of digital impressions just as they do VPS impressions.
5
Additionally, when placing esthetic anterior restorations, many
adhesivematerials canbe difficult tohandle, requiremultiple steps
to ensure predictable bond strength, and involve tedious and time-
consuming tasks for removing excess cement.
6,7
However, when a
combination of adhesive luting materials is used to simplify the
indirect restoration placement process, the challenges associated
with the adhesive cementation process can be avoided.
In particular, restoration surfaces can be chemically conditioned
using a silanating agent (e.g., Monobond Plus) to promote predict-
able and long-lasting bonds between all-ceramic materials (e.g., IPS
Empress CADMulti) and preparations, and a single-component. A
light-cured universal adhesive (Adhese Universal) can be placed
in a quick and efficient manner, regardless of which etching tech-
nique is desired (e.g., self-etch, selective enamel- etch or total-etch).
Then, the restorations can be placed using an esthetic light-and
dual-curing adhesive luting composite (Variolink Esthetic) that is
ideal for esthetic all-ceramic restorations, enabling precise shade
matching to surrounding teeth while also promoting easy clean-up
of excess cement following pre-polymerization with light.
CASE PRESENTATION
A 27-year-old female who was unhappy with the appearance of
her anterior teeth presented with a previously root-canal treated
tooth #8 that was starting to darken, and the laterals had old
composite resin veneers. The patient also displayed a high lip line
and gummy smile (Fig. 1). The patient was interested in longer-
lasting treatment than composite veneers, since her existing resto-
rations had already been re-restored once.
A comprehensive examination was performed in addition to a
smile evaluation and periodontal examination. The patient showed
no signs of bruxism or clenching habits. Soft-tissue crown length-
ening could potentially allow for longer teeth, withoutmaking them
appear too long, and also reduce the gumminess of the smile. There-
fore, topical analgesic was applied, the soft tissue was probed, and
bone sounding was performed to determine if the cervical margins
could be altered without impinging on the biological width.
TREATMENT PLANNING
When examining the teeth involved, it was determined that the
incisal edges were in a good position, so only apical lengthening
