jcda
J Can Dent Assoc 2014;80:e22
ca
ESSENTIAL DENTAL KNOWLEDGE
Published by
The Canadian Dental Association
– Any pivotal movement that appears to be located well below the base of the
prosthetic abutment may indicate fracture or failure of the implant. If so,
expect discomfort on movement.
DES CONNAISSANCES
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DENTAIRES INDISPENSABLES
4. Assess whether or not the crown is vertically mobile, especially during early
l’Association dentaire canadienne
stages of abutment screw loosening. There is a limit to how high the crown can
be raised.
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Figure 2: Clear view to the abutment screw
after filling material is removed.
Figure 3: Ensure there is no margin
impingement from the sides of the crown
as the abutment screw driver is placed.
5. Be careful with a loose crown/abutment assembly that has rotational but no
lateral/vertical movement. The abutment and screw may be a single structure
without a separate internal screw (i.e., a “solid post”). Therefore, no occlusal
access will be possible for the abutment screw and caution should be used when
removing the crown.
6. Radiographic examination may:
– Indicate good boney support for the implant. The entire body of the implant
fixture should be intact, eliminating the possibility of an implant fracture.
– Reveal a microgap between the abutment and the occlusal platform of the
implant (Fig. 1).
– Reveal a fracture of the abutment screw within the body of the implant still
present as a loose crown.
7. There is a higher prevalence of screw loosening in patients with a history of
bruxism and/or clenching.
Diagnosis
Based on the clinical examination and radiographic evidence, a diagnosis of loose implant abutment screw
is determined.
Differential Diagnosis
Failed cement seal; fractured implant; failed implant; fractured prosthetic abutment
Treatment
Common Initial Treatments
1. Advise patient of the possible sequelae of trying to remove the abutment/crown assembly.
– In the worst case scenario, remake of the restoration may be required if it is not poss X