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CLINICAL
TIP
Managing Implants in Patients with Bruxism
by
Siamak Abai, DDS, MMedSc
For patients who have undergone implant therapy,
the potential for parafunctional developments due to
bruxism is a cause for concern. Consequences can range
from excessive wear on the restoration and surrounding
dentition, to lack of osseointegration, to loosening or fracture
of the implant restoration. Mitigating these consequences
can help ensure the best possible treatment outcome. Given
the paramount importance of the patient’s health and the
long-term viability of the restoration, careful consideration
of implant design and use of an occlusal guard are strongly
recommended to prevent overloading of the implant and
subsequent periodontal issues related to parafunctional
habits such as bruxism.
Clinical research has produced an inconclusive consensus on
the definition of bruxism and its relation to implant dentistry.
However, criteria found throughout the literature allow the
dental community an extrapolation to serve as a diagnostic
aid in everyday practice. Bruxism is the condition classified
by routine diurnal and nocturnal parafunctional activity that
encompasses bracing, clenching, grinding and gnashing of
dentition. 1–5 Published studies present the condition to be
the most common oral habit, purporting that as high as
80 percent of the population display reasonable cause for
classification. 6 As ever-increasing numbers of patients seek
implant treatment, the statistics involving bruxism cannot
be disregarded.
The lack of consensus should not prevent clinicians from
addressing the real risks posed by bruxism to implant
therapy. Patients with bruxism are eliminated from the
majority of clinical trials involving dental implants, delaying
the establishment of a scientific causal relation between
bruxism and implant failure. 1,3 Scenarios involving the
connection of the two topics cannot so easily be deviated
from in actual treatment planning, calling the clinician to be
knowledgeable in both areas. Using indicators such as tooth
wear as clear-cut diagnostic tools in research settings may lead
to false conclusions that can prevent necessary treatment.
The prevalence of tooth wear alone is a misrepresentation
of the current state of bruxism in a patient and is not
indicative of an ongoing problem. 1,5 Practical guidelines for
the treatment of patients with bruxism are based on expert
opinions rather than on clinical literature until conclusive
studies generate a consensus. 4,7 Treatment absent of these
recommendations can result in implant overload.
Implant Complications and Failure
Implant failure can result from biological and biomechanical
complications. Biological complications can be further
subdivided into early and late failures. 1 Characterization
of early failure involves implant loss before the final
prosthetic restoration due to insufficient osseointegration.
Pathological bone loss after osseointegration is the defining
representation of late failure. 1 Excessive and continuous use
of the muscles of mastication allows patients with bruxism
to exhibit higher maximum bite force than their average
counterparts. 6 The resulting compression causes additional
movement throughout the implant, decreasing the likelihood
of an uninterrupted direct interface between implant and
bone. 5 Complications are determined as biomechanical in
cases where one or more of the implant system components
fail; including but not limited to fracture of the implant
itself, loosening of the connecting abutment screw and
excessive wear of the mesostructural components found in
overdentures. 1 Notwithstanding the lack of consensus in the
literature, the success of implant treatment can be greatly
complicated by circumstances presented by bruxism.
The effects of bruxism are compounded when considering
the occlusal resistances exhibited in natural teeth compared
to those in implant restorations. Lacking the periodontal
membrane associated with natural dentition, implants
conduct forces directly into the underlying bone. 4 When a
light force (20 N) is applied, an osseointegrated implant can
only be intruded by 2 µm, whereas a natural tooth can be
intruded by about 50 µm. 1 The lack of compressible structure
highlights the risks associated with bruxing patients. Patient
complaints must be carefully considered when checking
– Clinical Tip: Managing Implants in Patients with Bruxism – 79