Download Endodontic flare-ups and associated factors in a Taiwanese hospital

Endodontic flare-ups and associated factors in a Taiwanese hospital
YI-FEN CHEN
YU-HEN LIN
CHENG-CHANG CHEN
HUI-LING CHEN
Department of Dentistry, Chang Gung Memorial Hospital, Linkou, Taipei County, Taiwan, ROC.
A flare-up following root canal treatment (RCT) is a frustrating problem to both patients and
dentists. The purpose of this study was to evaluate the incidence of endodontic flare-ups of Taiwanese
patients at Chang Gung Memorial Hospital (CGMH), Linkou, Taiwan in a prospective survey. An
unscheduled phone call and/or an emergency visit due to severe pain and/or swelling following RCT was
defined as a flare-up. Six hundred and fifty-eight teeth were treated in the Endodontic Department of
CGMH by senior residents or attending doctors in a period of 3 months. Patient’s demographics, and
clinical and radiographic data were recorded at the time of the RCT. We found that the overall incidence
of flare-ups was relatively small (1.98%). The incidence of flare-ups was significantly correlated with
presenting symptoms of spontaneous pain (5.48%, p=0.025), percussion pain (12%, p=0.000), and root
canal overfilling (7.89%, p=0.034). However, there was no correlation between the incidence of flare-ups
and patient age, gender, tooth position, periapical diagnosis, pulpal diagnosis, type of treatment, or type
of operator. We concluded that the occurrence of flare-ups is significantly related to preoperative
spontaneous pain, percussion pain, and root canal overfilling. （J Dent Sci, 2(1)：39-44 , 2007）
Key words: flare-ups, root canal treatment, overfilling, preoperative pain.
Severe pain and/or swelling following root canal
treatment (RCT) are serious sequelae. This is
upsetting to both the patient and dentist. The flare-up
phenomenon is complex, and the reasons for such
exacerbations are not always clear. Undoubtedly it
involves a number of aspects related to local tissue
adaptation, changes in periapical tissue pressure, a
microbial imbalance, immunological phenomena, and
various psychological factors1.
A flare-up is a true complication characterized by
the development of pain or swelling both during and
after endodontic therapy, and is of sufficient severity
to require an unscheduled visit for emergency
treatment. Different incidences of flare-up after RCT
have been reported. These variations are the result of
examining different factors and conditions related to
flare-ups. For example, Morse et al.2 reported an
incidence of flare-up of 20% (using swelling as the
Received: December 1, 2006
Accepted: February 27, 2007
Reprint requests to: Dr. Yi-Fen Chen, Department of Dentistry, Chang
Gung Memorial Hospital, No. 5, Fu-Hsing Street,
Kweishan, Taoyuan, Taiwan 33375, ROC.
J Dent Sci 2007‧Vol 2‧No1
only criterion) after treating asymptomatic teeth with
pulp necrosis and chronic apical periodontitis.
Walton and Fouad3 determined an incidence of
flare-up of 3.17% using pain and/or swelling as the
criteria in a prospective study, and with the same
criteria, Imura and Zuolo4 found an incidence of
flare-up of 1.58%. Other investigators5-7 have reported
varying incidences of flare-ups, based on different
criteria and sample sizes.
Although many factors associated with flare-ups
have been examined, those factors frequently related
to the occurrence of flare-ups include the gender and
age of patients8, the presence of a periapical lesion3,7-9,
and a history of preoperative pain3,8. A prospective
study involving a large number of teeth can clarify the
factors related to the presence of posttreatment
sequelae. Therefore, the purpose of this study was to
examine the overall incidence of flare-ups in a total of
658 RCT cases performed during a period of 3 months
at Chang Gung Memorial Hospital (CGMH), Linkou,
Taiwan. Relationships of the incidence of flare-ups
after RCT with patients’ demographics (age and
gender), tooth type, pulp/periradicular diagnosis, the
presence or absence of preoperative pain, initial RCT
or retreatment, and type of operator were analyzed.
39
Y.F. Chen, Y.H. Lin, C.C. Chen, et al.
MATERIALS AND METHODS
Data on 658 teeth receiving either non-surgical
initial RCT or retreatment in the Department of
Endodontics, CGMH during a 3-month period from
July to September 2002 were collected. These RCTs
were performed by either senior residents or attending
doctors. Each patient’s demographics, the tooth
position, presenting symptoms, and the presence
or absence of preoperative pain (spontaneous or
percussion pain) were obtained at the patient’s first
visit. The pulpal diagnosis (normal, irreversible
pulpitis, pulp necrosis, reversible pulpitis, or previously treated) and periapical diagnosis (normal,
chronic apical periodontitis, acute apical periodontitis,
chronic periapical abscess, acute periapical abscess, or
a non-endodontic lesion) of each treated tooth were
also recorded according to the definition of the
Glossary of Endodontic Terms 200316. Periapical
radiography after RCT was performed to determine
whether there was root canal overfilling. A special
sheet was used to record all data for each patient.
Treatment protocols were standardized: each
patient was anesthetized with 2% xylestesin with or
without epinephrine, a rubber dam was put in place,
and a 3.0% NaOCl solution was used for irrigation of
the root canal throughout the treatment. The working
length (from the crown to 0.5 mm above the
anatomical root apex) was measured using an
electronic apex locator and confirmed by periapical
radiography. Apical preparation was completed to
the working length with either hand-held stainless
steel files or nickel-titanium rotary instruments. In
retreatment cases, the previous root canal filling
material was removed using Gates Glidden burs, hand
files, and eucalyptol, and then the root canal
preparation was performed. All RCT cases were
obturated with either gutta-percha cones or root canal
sealer of canals (Showa ShizaI Kako, Tokyo ) using
a lateral condensation technique or with Roth 801 root
canal sealer (Roth International, Chicago, IL) using
a vertical condensation technique. Root canal
overfilling was defined as finding gutta-percha or
sealer beyond the radiographic apex. Operators
decided the best time to obturate the root canals based
on the diagnosis of each tooth, clinical findings, and
available chair time. Calcium hydroxide was the only
intra-canal medication put in place if completing
the RCT required more than 1 visit. Patients were
instructed to phone the dentist or come back for an
40
emergency visit if the tooth was severely painful or
swelling developed at the gingival or alveolar mucosa
during the first 2~3 days after treatment. If a patient
called with a complaint of severe pain and/or swelling
and returned to the clinic for emergency treatment, a
flare-up was recorded. A second flare-up following the
first flare-up was not included in this survey. All of the
above procedures were performed by 2 attending
doctors and 2 senior residents. No cases of RCT
handled by dental students were included in this study.
The overall incidence of endodontic flare-ups
was calculated. The correlations between the incidence of flare-ups and various related factors such
as patients’ demographics, the tooth position, pretreatment symptoms, the pulpal / periradicular
diagnosis, type of treatment, type of operator, and the
presence or absence of overfilling were analyzed
by the Chi-squared test. A p value of ≤ 0.05 was
considered statistically significant.
RESULTS
Of the 658 teeth with RCT, flare-ups occurred in
13 teeth (1.98%). The demographic and clinical data
of the 13 flare-up cases are described in Table 1.
Correlations between the incidence of endodontic
flare-ups and the patients’ demographic, clinical, and
radiographic data are shown in Table 2. There were no
significant correlations between the incidence of
endodontic flare-ups and patients’ age, gender, tooth
position, periapical diagnosis, pulpal diagnosis, type
of treatment, or type of operator. However, the
incidence of endodontic flare-up was significantly
correlated with pretreatment spontaneous pain
(p=0.025), percussion pain (p=0.000), and root canal
overfilling (p=0.034).
DISCUSSION
Both case randomization and a large sample size
are critical to clinical studies involving many variables.
These two factors are generally easier to achieve in a
retrospective study than a prospective study. However,
standardization of clinical parameters in evaluating
results is more accurate for a prospective study
compared with a retrospective study. Because this
clinical study was related to posttreatment flare-ups,
many variables such as the criteria for evaluating the
results and the RCT technique needed to be clarified
J Dent Sci 2007‧Vol 2‧No1
Endodontic flare-ups
Table 1. Demographic and clinical data of 13 flare-up cases
Case number
Tooth position
Gender
Pulpal diagnosis
Periapical diagnosis
Spontaneous pain
Percussion pain
Overfilling
1
#11
F
PT
CAP
-
-
+
2
#21
F
PT
CAP
-
-
-
3
#46
M
IP
N
-
+
+
4
#24
M
IP
N
-
+
+
5
#22
F
PN
CAP
-
-
-
6
#13
F
PT
CAP
-
-
-
7
#37
F
PT
CAP
-
+
-
8
#12
F
N
N
+
-
-
9
#46
F
PT
CAP
+
+
-
10
#47
F
RP
N
-
-
-
11
#37
M
IP
N
+
+
-
12
#46
F
PT
CAP
-
-
-
13
#37
F
PT
CAP
+
+
-
PT, previously treated; IP, irreversible pulpitis; PN, pulp necrosis; N, normal; RP, reversible pulpitis; CAP, chronic apical periodontitis.
before the study began for comparison. Therefore, our
investigation used a prospective study format which
enabled us to analyze the association of demographic,
clinical, and radiographic data of 658 RCT teeth with
the incidence of endodontic flare-ups.
The results of our study showed a low incidence
of flare-ups (1.98%) after RCT, which was similar to
those reported by Imura and Zuolo (1.58%)4 and
Siqueira et al. (1.90%)11. It appears that when RCT is
conducted under sound biological principles, with
contemporary scientifically based techniques, by
skillful operators like senior attending doctors or
residents, a low overall incidence of endodontic
flare-ups can be expected.
The results of the present study showed no
significant relationship of patients’ age, gender, or
tooth type with the incidence of endodontic flare-ups.
Our findings are in agreement with those from several
previous studies3,4,12. In contrast, a retrospective study
by Torabinejad8 showed a significant positive correlation of flare-ups with patients’ ages of between 40
and 59 years, female patients, and mandibular teeth.
The present study also showed that 10 female patients
experienced flare-ups among the 13 patients (Tables 1,
2). In general, female patients have more-sensitive
responses to RCT than male patients. Since the
J Dent Sci 2007‧Vol 2‧No 1
definition of flare-ups is relatively subjective, it may
be easier for female than male patients to feel and
remember the discomfort after RCT even when they
undergo the same treatment. This might have led to
more female cases of flare-ups being reported by this
prospective study.
An important diagnostic factor is the presence of
preoperative pain when evaluating acute exacerbations
after RCT. Many other studies3,4,8 showed higher
frequencies of flare-ups in patients with preoperative
pain. In this study, we also showed a significant
relationship of the presence of preoperative spontaneous pain (4/13) and percussion pain (6/13) with
a higher incidence of flare-ups. It appears that the
presence of preoperative complaints is an excellent
predicator for flare-ups.
Many studies3,4,7,11 showed a significantly higher
incidence of flare-ups in cases with a periapical lesion
than in those without a periapical lesion. On the other
hand, Fox et al.14 and Frank et al.15 found that an
absence of periapical radiolucency was associated
with a higher incidence of flare-ups and a higher level
of postoperative pain. In the present study, the
classification of the pulpal/periradicular diagnosis was
based on terms defined by the American Association
of Endodontists16. According to our survey, there was
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Y.F. Chen, Y.H. Lin, C.C. Chen, et al.
Table 2. Correlations between the incidence of endodontic flare-ups and patients’ demographic, clinical, and radiographic data
Total No. of cases
No. of cases of flare-up (%)
0.371
Patient age (year)
66
126
121
145
133
67
3 (4.55)
1 (0.79)
2 (1.65)
4 (2.76)
2 (1.50)
1 (1.49)
Patient gender
Male
Female
248
410
3 (1.21)
10 (2.44)
Tooth position
Maxillary anterior
Maxillary premolar
Maxillary molar
Mandibular anterior
Mandibular premolar
Mandibular molar
45
82
117
220
94
100
0 (0.00)
0 (0.00)
3 (2.56)
6 (2.73)
2 (2.13)
2 (2.00)
Periapical diagnosis
Normal
Chronic apical periodontitis
Acute apical periodontitis
Chronic periapical abscess
Acute periapical abscess
Non-endodontic lesion
299
319
24
12
3
1
5 (1.67)
7 (2.19)
1 (4.17)
0 (0.00)
0 (0.00)
0 (0.00)
Pulpal diagnosis
Normal
Irreversible pulpitis
Pulpal necrosis
Reversible pulpitis
Previously treated
110
74
116
11
347
1 (0.91)
2 (2.70)
2 (1.72)
1 (9.09)
7 (2.02)
Type of treatment
Initial treatment
Retreatment
274
384
5 (1.82)
8 (2.08)
Type of operator
Attending doctor
Senior resident
389
269
7 (1.80)
6 (2.23)
Spontaneous pain
With
Without
73
585
4 (5.48)
9 (1.54)
Percussion pain
With
Without
50
608
6 (12.0)
7 (1.15)
0~18
19~29
30~39
40~49
50~64
> 65
1.000
0.731
0.626
0.378
1.000
0.750
0.025
0.000
Overfilling
With
Without
42
p value
0.034
38
620
3 (7.89)
10 (1.61)
J Dent Sci 2007‧Vol 2‧No1
Endodontic flare-ups
no significant difference in the frequency of flare-ups
among cases with different previous periapical
manifestations. These results might have been due to
the small sample size in some groups of periapical
pathoses such as acute and chronic periapical abscess.
In addition, pulpal and periradicular diagnoses are
often determined after clinical and radiographic
examinations, and it usually takes some time to detect
periradicular lesions on radiographs. Patients with a
preoperative lesion might have had a higher pain
threshold and been less sensitive to discomfort. In
case 8 (Table 1), the patient had preoperative pain
caused by a periodontal ligament (PDL) injury from
heavy occlusion or traumatic force of bruxism. In this
situation, the PDL may have been inflamed with
abundant chemotactic factors around the tooth, and
this much more easily can cause postoperative pain of
the tooth.
The retreatment procedure did not cause any
additional posttreatment flare-ups in the present study.
This finding was in agreement with those of Walton
and Fouad3 and Siqueira11. Removal of the inflamed
contents and administration of appropriate medications may account for the lower incidence of
flare-ups. In contrast, Trope et al.7 and Imura and
Zuolo4 showed a significantly higher incidence of
flare-ups in retreatment cases than in the initial
treatment cases.
Mechanical irritation, including over-instrumentation and root canal overfilling, can cause
periradicular inflammation13. Apical extrusion of
debris during gutta-percha point removal may cause
acute exacerbation of chronic inflammatory conditions17. Therefore, apical over-instrumentation and
overfilling can disrupt normal periapical healing, and
lead to the development of new periapical lesions18.
Clinically, extrusion of filling materials beyond the
root apex can occur in teeth with an unsatisfactory
apical stop as with an over-instrumented apex.
Georgopoulou et al.10 observed an increase in flare-ups
in cases with over-instrumentation. In fact, penetration
of the apical foramen with large instruments not only
can result in severe periapical tissue injury, but it can
also cause lack of an apical stop and extrusion of
filling materials during obturation of the root canal
system. In a long-term follow-up study, non-vital teeth
with periapical lesions that were overfilled had a
significantly reduced success rate of just 76%,
compared to 94% for those teeth which were filled
close to the apex19. Several other follow-up studies
J Dent Sci 2007‧Vol 2‧No 1
have also reported that the presence of excess root
filling material is associated with impaired healing of
periapical lesions19,20. Although the reasons for this
have not yet been clarified, there may be several
events which occur individually or collectively to
interrupt healing. These include procedures involved
in canal preparation that may lead to overfilling such
as: (i) damage to the root apex and periapical tissues
through over-instrumentation, (ii) extrusion of debris
which may contain microorganisms, elements of
necrotic pulp, and infected or uninfected dentin chips
from the root canal21,22, and (iii) the presence of excess
root filling material in the periapical tissue which may
act as a foreign body and cause retardation of the
tissue repair process. In the present study, 38 (7.89%)
cases of root canal overfilling (37 cases of guttapercha point and 1 case of cement overfilling)
experienced endodontic flare-ups. However, Morse et
al.2 intentionally enlarged the apical foramen of teeth
that required RCT and reported a lower incidence of
“flare-ups” than those without apical penetration.
An unexpected result was that there was no
significantly higher incidence of flare-ups in teeth
treated by senior residents compared to teeth treated
by attending doctors. This can possibly be explained
by operators with sufficient RCT experience using
sound biological principles and contemporary
techniques can achieve good endodontic outcomes
after RCT, resulting in no difference in the occurrence
of flare-ups between the senior resident and attending
doctor groups.
We concluded that the incidence of endodontic
flare-up was 1.98% after RCT in this study. The
occurrence of flare-ups was significantly related to
preoperative symptoms, such as spontaneous pain and
percussion pain. There was also a highly significant
association of the frequency of flare-ups with the
presence of root canal overfilling.
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