]
First and foremost, there are certain criteria that
dentists ought to consider when deciding whether to
perform tooth extractions before RT. Before RT, periodontally
weak teeth in the RT field, teeth with fractures
and loss of substance that cannot be restored,
teeth with any acute or chronic infection at the root tip,
semi-impacted teeth at risk for pericoronitis, and teeth
that are elongated on the opposing edentulous alveolar
crest must be extracted. However, impacted teeth that
have not been exposed to the oral environment and are
wholly bone-covered may be left in place.[]
The timing of tooth extraction remains an unresolved
issue for patients diagnosed with head and
neck cancer. While pre-RT tooth extraction is generally
regarded as a safer option when compared to extractions
conducted during or after RT, recent studies
have indicated that pre-RT tooth extraction can also
lead to the development of ORNJ.[] It is prudent to
allow an adequate wait time between the tooth extraction
procedure and the onset of the RT for the wound
to undergo satisfactory healing. It is recommended
that this period not be shorter than 14 days[] to facilitate
the healing process of soft tissues and reduce
the risk of potential complications, including ORNJ
development. It is recommended not to perform
tooth extractions after RT to minimize the occurrence
of ORNJ, but if mandated, post-RT tooth extractions
should be carried out within the first 5-6 months after
the completion of RT. This timing takes into account
the expected progression of tissue fibrosis and vascular
deterioration resulting from RT.[,]
Some authors have argued that pre-RT extractions
may be associated with a lesser risk of ORNJ
development.[-] The studies conducted by Kojima
et al.[] and Moon et al.[] were unable to
identify any statistically significant correlation between
tooth extraction before RT and the occurrence
of ORNJ. However, conversely, some other authors
have pleaded that pre-RT extractions may also be
linked to a heightened risk of ORNJ, similar to post-
RT extractions.[,] Owosho et al.[] conducted
a retrospective cohort study that included 1023 patients
diagnosed with oral cavity or oropharyngeal cancers. The study found that only 18% of cases of
ORNJ had tooth extractions before RT, suggesting a
limited but significant connection between pre-RT
extractions and an increased likelihood of developing
ORNJ. Similarly, in a critical review by Wahl, the
authors emphasized that the incidence of ORNJ after
pre-RT tooth extraction (3.2% vs. 3.5%; p>0.05) was
approximately identical to the ORNJ incidence in patients
with post-RT post-extractions.[] As a result,
the extraction of teeth before RT should be regarded
as a substantial risk factor for ORNJ. That is why dental
and radiation oncologists should engage in comprehensive
discussions regarding the pre-RT tooth
extraction decision. When the decision is to perform
tooth extraction, it is imperative for the responsible
physician to ensure that the patient is adequately informed
and their consent is obtained.
It is widely advised that individuals scheduled
for RT undergo comprehensive radiographic and
clinical dental assessments. These evaluations are
typically conducted to identify any required interventions
and administer them approximately 2-3
weeks before the initiation of RT.[] Nevertheless,
in certain instances, such as traumatic events or situations
where RT results in unanticipated and intensified
adverse responses, such as tooth fractures, tooth
extraction may become mandatory during the RT
course. It is crucial to bear in mind that the likelihood
of developing ORNJ increases when tooth extractions
or mandibular surgery becomes necessary
during RT. Therefore, it is advisable to prioritize
minimally invasive interventions, whenever feasible,
to mitigate the associated risk.[]
Limited research has been conducted regarding
the potential hazards associated with surgical interventions
performed on patients during RT. The existing
literature primarily consists of recommendations
for precautionary measures before or during surgery.
[,] Indeed, the hypoxia resulting from vascular
occlusion and the development of fibrosis due to hypoxic
activity play a significant role in the pathogenesis
of ORNJ. This biological activity sets off a detrimental
cycle, exacerbated by the active involvement of
inflammatory mediators. Consequently, the destructive
effects of ORNJ on the bone structure become irreversible
in the later stages, making them imperceptible
during the initial application of RT. As a result,
the principal objective of surgical procedures, such as
tooth extraction, performed during RT should be to
minimize any further damage to the affected tissue
and mitigate the risks of infection and ORNJ.
An additional inquiry that arises in the context of
dental interventions for patients undergoing or having
undergone RT pertains to the efficacy of administering
antibiotics to patients before or following a
tooth extraction, intending to reduce the likelihood
of developing ORNJ. Several authors have suggested
the administration of clindamycin as a prophylactic
measure for 10 days, with the initial dose given 3 days
before surgical procedures and tooth extractions.[]
However, the efficacy of this application remains inconclusive
due to a lack of definitive evidence. While
it is not often required, the administration of antibiotics
in instances of acute infection may have a beneficial
impact on the process of wound healing following
a surgical procedure.
The survival rate of head-and-neck cancer patients
has improved significantly in the past two decades
thanks to advancements in treatment methods and
standard care. As a result, patients now have a longer
life expectancy. However, this also means that the side
effects of RT, both short-term and long-term, have become
more significant for these patients.[,] Individuals
who receive RT targeting the head-and-neck
region face an elevated susceptibility to dental caries.
This heightened risk arises from the permanent
reduction of saliva, increased consumption of sugar,
and the development of a cariogenic flora.[] During
the follow-up period, a significant proportion of patients
in this group experienced the loss of multiple
teeth. This fact can be attributed to various factors,
including the extensive and rapidly progressing tooth
decay process caused by reduced saliva production,
degradation of salivary components, and complications
arising from RT, such as mucositis, which has
a detrimental impact on oral hygiene.[,] In turn,
it is imperative for patients to undergo dental rehabilitation
to enhance their physiological abilities, specifically
in terms of mastication, deglutition, and oral
occlusion, thereby ensuring the fulfillment of their
nutritional requirements in their daily lives.[]
It is not advisable to utilize removable prostheses
in head-and-neck cancer patients who are currently
undergoing or are scheduled to undergo RT
unless there is a compelling medical need. This recommendation
is based on the potential risk of ORNJ
resulting from the degradation of salivary content
caused by RT and the compression of the prosthesis.[] Due to anatomical changes in the orofacial
region and jaws, such as dry mouth, traditional removable
dentures may not provide an appropriate
and comfortable fit following RT and or surgery. Consequently, dental implants are often preferred.
[,] The rationale behind this decision is commonly
rooted in the notion that dental implants
have the potential to offer superior oral rehabilitation
outcomes concerning chewing ability, aesthetic
appearance, and speech function among individuals
within this specific patient demographic.[] As a
result, implant-supported fixed or semi-fixed dental
prostheses should be favored over conventional ones
if prostheses are medically needed.
Given that the dental implant placement procedure
is an invasive surgical intervention, it is imperative
to subject it to a comprehensive evaluation using
criteria analogous to those employed for tooth extraction.[,] While it is generally advised to wait 6-12
months after RT for safer implant placement, there
is currently a lack of substantial scientific evidence
regarding the optimal timing.[,] Nevertheless,
it is necessary to assume that if the dental implant is
placed more than 6-8 months after RT, there is a possibility
that the resulting scar may undergo fibrosis
formation. This process occurs due to the obstruction
of blood vessels and insufficient blood flow to the affected
bone. Consequently, this may result in bone
resorption due to inadequate healing and potentially
ORNJ.[] Hence, it is reasonable to suggest that the
most appropriate time frame would be approximately
5-6 months following RT or 3-4 months preceding
RT, as this coincides with the ideal duration for the
process of dental implant osseointegration.[]
ORNJ appears to occur more frequently in patients
with complete dentition. However, the absence
of some teeth or an edentulous state does not necessarily
eliminate the risk of developing ORNJ totally,
which contradicts prevailing beliefs. The prevalence
of spontaneous occurrences of ORNJ among all ORNJs
is estimated to be approximately 10.8%.[] It is
also reasonable to expect the formation of the ORNJ
as a result of trauma caused by removable dental
prostheses in patients with extensive tooth loss.[]
Therefore, it is advisable to modify or substitute current
dental prostheses.
Regular dental check-ups are essential for patients
with head and neck cancer undergoing RT or C-CRT
to prevent ORNJ and to ensure timely diagnosis and
treatment if it does occur. As a result, patients who
have undergone RT should be evaluated clinically and
radiologically with a frequency of 3-6 months, depending
on their susceptibility to these complications. This
is because RT has a deleterious effect on the salivary
glands, which causes dental caries formation, xerostomia, and indirectly periodontal disease by affecting saliva
flow and lubrication and disrupting the anti-caries
effect.[] It is advisable to administer oral hygiene
education to this cohort of patients during each followup
visit, accompanied by a comprehensive explanation
of the potential signs, symptoms, and complications associated
with RT.
Finally, another factor contributing to the increased
rate of ORNJ is the administration of chemotherapeutic
agents, particularly bone-acting ones, as
part of the treatment.[] While RT is a significant
triggering factor for oral complications, co-administration
of bone-acting and antiangiogenic medications
may render patients more vulnerable to ORNJ.
[] The accurate distinction of whether the necrosis
observed in patients taking bone-influencing medications
is ORNJ or medication-related osteonecrosis is a
separate but critical problem that must be resolved. In
this setting, Zadik et al. emphasized the importance
of considering the diagnosis of ORNJ only in cases
where there has been exposure to radiation exceeding
40 Gy. This is crucial for avoiding misdiagnosis
and ensuring appropriate treatment, especially in
patients using bone-acting medications. In addition,
the authors suggested that medication-related osteonecrosis
should be considered a highly probable diagnosis
in cases where the radiation exposure is <40
Gy.[,] Therefore, using bone-acting medications
in a rational and limited manner can be a preventive
measure for jaw osteonecrosis. This approach can also
help avoid the unknown contributing effects of these
medications on the development of ORNJ and the diagnostic
challenges associated with their use. Hence,
it is imperative to implement comprehensive preventive
measures and administer more aggressive dental
interventions and follow-up procedures for this particular
cohort of patients (Table 1).
Table 1 The recommendations, explanations, and precautions for avoiding osteoradionecrosis of the jaw
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