24
|
CERECDOCTORS.COM
|
QUARTER 2
|
2015
C A S E S T U D Y
| | |
B Y J O N AT H A N K . J A M E S , D . D . S .
an at-risk, previously endodontically treated single tooth presents a restorative challenge
because the
dentist must decide between retreating the tooth or removing it, utilizing a fixed bridge or implant, and selecting a cement-
retained or screw-retained implant crown. Many factors (e.g., patient preference, risk of decay and peri-implantitis, esthetics,
durability and longevity) are important considerations when planning the appropriate treatment. This article examines the decision
process that led to the selection of a single-tooth, screw-retained hybrid abutment implant crown.
Reducing Risk: Single Screw-retained
Hybrid Abutment Implant Crown
Examining the Decision Process
INTRODUCTION
The debate about whether to treat a single at-risk tooth with
endodontics, or extract it and replace it with an implant, continues.
Although this decisionmay appear simple, choosing between saving
a tooth and placing a substitute depends on the specific situation, the
patient’s desires, and appropriateness of materials and techniques.
Many dental professionals believe that saving the tooth provides the
best outcome; however, when it comes to previously endodontically
treated teeth, additional factors require consideration.
In a report by Hepworth et al., the authors determined that
previously endodontically treated teeth with a periapical lesion
had only a 66% success rate after retreatment. Another study by
Farzaneh et al. found that if a tooth needs retreatment for peri-
apical lucencies, the chance of failure increases, lowering the
success rate by more than 15%.
Additional complications, including apical surgery and loss of
periodontal support, can also reduce the success of retreatment. For
clinical situations in which utilizing the patient’s existing tooth is
not ideal, considering other treatment modalities may be necessary.
Fixed bridges and removables offer alternative and non-invasive
options to endodontic retreatment and implantation. By removing
the at-risk and previously endodontically treated tooth, dentists
eliminate potential for further decay, infection or problems asso-
ciated with the tooth. However, as a “permanent” treatment to
provide the illusion of the missing tooth, a fixed bridge utilizes the
adjacent natural teeth to support the non-removable prosthesis.
Although a fixed bridge can be esthetically pleasing, it typically
requires preparation of the adjacent natural teeth, making them
prone to decay, plaque accumulation, and periodontal disease.
An alternative to avoid preparation of natural dentition, remov-
able prostheses are not permanent and typically least invasive and
expensive. This treatment option, however, utilizes bulky wire
and multiple teeth to maintain adequate retention and support.
By far the most uncomfortable for patients, they must be cleaned
daily and removed while sleeping.
A restored dental implant, on the other hand, provides a perma-
nent and highly esthetic tooth replacement, as it most similarly
mimics a natural tooth in shape and function. Unlike fixed bridges
and removable prostheses, restored implants eliminate the need
for preparing adjacent teeth, contribute to greater patient comfort
and are known for their stability and ideal jaw bone preservation.
Similar to all dental procedures, however, implant placement
requires comprehensive diagnosis and treatment planning.
Fortunately, improved technology and advanced materials have
enhanced the success and function of implant restorations. Implant
designs and coatings facilitate greater osseointegration, reducing
the loss of orofacial support caused by bone loss. Advanced
computer software enables complete implant mapping and design
for accurate and precise treatment planning. These developments
also contribute to successful implant restoration design.
In fact, CAD/CAMrestorations demonstrate comparable results
to conventional restorations, and the application of newmaterials,
reduced labor, cost effectiveness and quality control offer several
advantages. This technology can be used in office to design and
mill implant abutments and restorations, improving efficiency.
However, despite their ideal esthetics, placing them on implants
can prove challenging.
To retain abutments and restorations, clinicians have traditionally
utilized twomethods: cement or screws. Cement-retained implants
connect the implant to the abutment in the oral cavity, and although
a variety of cement types are available to securely seat restorations,
complications can arise from failure to remove the excess.
A prospective clinical endoscopic study completed by Wilson
found that excess dental cement was associated with signs of
