Download Clinical management of severe external root resorption

Case Report
Clinical management of severe external root resorption
TIEN-CHUN KUO 1,2,3
YA-AN CHENG 1
CHUN-PIN LIN 1,2
1
Graduate Institute of Clinical Dentistry, National Taiwan University, Taipe, Taiwan, ROC.
Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan, ROC.
3
Department of Dentistry, Taiwan Adventist Hospital, Taipei, Taiwan, ROC.
2
This case demonstrates external root resorption arrest and formation of an apical barrier by
conventional endodontic therapy combined with calcium hydroxide dressing and a mineral trioxide
aggregate (MTA) apical plug. The upper left central incisor exhibited severe external root resorption, and
a periapical radiolucent lesion received root canal treatment combined with calcium hydroxide dressing
for over 4 years. The dressing was renewed every 3 months, and the coronal portion was sealed with
composite resin. After detection of the apical barrier, a MTA apical plug backfilled with gutta-percha was
performed and the access carity was restored with composite resin. The patient has been regularly
recalled every 6 months, and no symptoms or signs hare been noted. Radiography showed the apical
lesion healed and the external root resorption had been arrested after 1 year.（Chin Dent J, 24(1)：59-63, 2005）
Key words: external root resorption, calcium hydroxide, apexification.
External root resorption occurs on the outer
surface of the root, and the causes for this may vary.
There are several types of external root resorption
with the most common being external inflammatory
root resorption. It may arise as a sequela of traumatic
injuy, orthodontic tooth movement, or chronic
infection of the pulp or periodontal structures 1.
External inflammatory root resorption is considered a
major resorptive condition without symptoms. The
treatment of external inflammatory resorption is
dependent on the etiology; nonsurgical root canal
treatment combined with a calcium hydroxide
dressing was recommended by Andreasen 2.
Mineral trioxide aggregate (MTA), well known
for its great biocompatibility, has demonstrated
excellent sealing ability in studies of dye penetration
and bacterial leakage even under blood contamination
conditions 3-5. MTA is widely applied in root-end
filling, perforation repair, and pulp capping. It can
Received: November 23, 2004
Accepted: February 19, 2005
Reprint requests to: Dr. Chun-Pin Lin, School of Dentistry, College of
Medicine, National Taiwan University and National
Taiiwan University Hospital, No. 1, Chang Te
Street, Taipei, Taiwan 10048, ROC.
Chin Dent J 2005‧Vol 24‧No 1
induce regeneration of periradicular tissues, such as
bone and cementum. The following case report
demonstrated nonsurgical root canal treatment of
severe external root resorption and the use of MTA as
an apical plug to promote periapical healing of an
open apex.
CASE PRESENTATION
A 19-year-old female patient was referred from
the orthodontic department for evaluation and
treatment of the upper left central incisor. The tooth
had suffered previously from a traumatic injury for
several years central. The patient mentioned that the
tooth had been treated in a local dental clinic nearly a
year ago and no symptoms had been noted since then.
Her medical history was noncontributory.
Clinical examinations revealed no mobility of
the upper left central incisor6, and the pocket depths
around the tooth were within a normal range.
Palpation and percussion tests induced no discomfort
or pain. The access cavity had been sealed with
cotton and Caviton®. The periapical radiographic film
showed several resorpted bowl-shaped lesions on the
external surface of the root combined with a
radiolucent lesion around the root apex, and the root
59
T.C. Kuo, Y.A. Cheng and C.P. Lin.
apex was open (Figure 1). The diagnosis for #9 was
prior root canal treatment with chronic apical
periodontitis combined with external root resorption
Figure 1. Initial x-ray film showing multiple bowl-shaped external
and an open apex.
Conventional root canal treatment combined
with calcium hydroxide dressing is the first choice of
treatment. We also consulted with an orthodontist for
avoiding any orthodontic force on #9 before the
external root resorption was undercontrol. In the first
appointment, canal debridement was performed
under rubber dam isolation, and poor order was noted
when the prior temparary fillings were removed. The
working length was determined by RootZX® and
radiographic film, and the initial working length was
19 mm (Figure 2). Apical discharge was noted during
instrumentation. The canal was debrided and irrigated
with 2.5% sodium hypochlorite solution. Pure
calcium hydroxide mixed with distilled water was
placed in the canal the first week. The calcium
hydroxide was renewed every week for 1 month until
the apical discharge had diminished.
After the discharge had been controlled, calcium
hydroxide paste was filled in the canal for
apexification. The patient was on 3-month regular
recall. The canal was recleaned, and apexification
was verified by the failure of a small instrument to
penetrateing through the apex after removal of the
dressing (Figure 3). If apexification is incomplete, the
canal would have to be repacked with the calcium
root resorption with periapical radiolucent lesions.
Figure 2. Working length determination. The radiographic film
Figure 3. A the 3-month recall. The calcium hydroxide dressing
shows the file position in the root canal.
had been washed out of the apical part.
60
Chin Dent J 2005‧Vol 24‧No 1
Treatment of external root resorption
hydroxide aste, and the periodic recall continued.
After 4 years and 7 months, the apical barrier
was detected using a #25 file, and radiographic film
(Figure 4) showed that a dentin barrier had formed 2
mm from the root apex.
The root canal was then cleaned and dried with
sterilized paper points. MTA powder was mixed with
distilled water and packed into 4 mm of the apical
end as an apical plug. A wet cotton pellet was placed
in the canal for over 24 hours to maintain a highhumidity environment. After the MTA had set, we
filled the residual canal space with gutta-percha and
Sealapex®. The access cavity was prepared and
restored with composite resin (Figure 5).
The patient was then on 6-month regular recall.
No symptoms or signs were noted. One year later, the
radiographic film showed that the external root
resorption had been arrested, and the periapical lesion
had healed (Figure 6).
Figure 4. Radiographic evidence of apexification. The apical
barrier was detected using a #25 file and by the failure of file
penetration.
DISCUSSION
There are various etiologies of external root
resorption, and in this case, pulpal space infection
Figure 5. Root canal obturation. Mineral trioxide aggregate was
Figure 6. At the 1-year follow-up. The periapical lesion had
packed into about 4 mm the apex as an apical plug, and the coronal
part was filled with gutta-percha.
healed, and we could trace the lamina dura around the root.
Chin Dent J 2005‧Vol 24‧No 1
61
T.C. Kuo, Y.A. Cheng and C.P. Lin.
leading to external root resorption in either the apical
or lateral regions of the root was the major etiology.
A history of trauma and orthodontic treatment also
contribute to the results of external root resorption.
Efforts by the orthodontist to avoid heavy forces on
the traumatized tooth may have minimized the
tendency for root resorption. Working length
determination is difficult with an open apex;
radiographic film and the paper point method
combined with an endometer can be helpful in
confirming the working length.
Treatment of inflammatory resorption is based
on removal or reduction of the source of infection7.
Non-surgical root canal therapy with the use of
calcium hydroxide as an intra-canal medicament is
recommended2. In this case, arrest of the external
resorption and induction of apical closure guided the
treatmentine. The purposes of calcium hydroxide
dressing were disinfection, creation of a
physicochemical barrier, and apexification. The
calcium hydroxide dressing can also help control
infection and maintain the root canal of high PH
value an environment suitable for hard tissue
formation and MTA setting8. Coronal leakage is also
a key factor causing failure, so we sealed the access
cavity with composite resin to avoid coronal leakage.
The usual time required to achieve apexification
is 6 to 24 months9, but in this case, it took over 4
years to achieve apical closure. Factors related to the
increased time might have been the severe condition
of the external root resorption and the wide diameter
of the root apex. There are no guidelines suggesting
how often the dressing should be renewed. It has
been reported that following the initial root filling
with calcium hydroxide, nothing is gained by
repeated filling either monthly or after 3 months for
at least 6 months)10. We agree that calcium hydroxide
should be renewed if the apical part of the dressing is
washed out.
Calcium hydroxide has been proven to induce
formation of an apical barrier, but the structure of this
barrier might be tunneled or the soft tissue may be
included11. We know that an apical seal is important
for the prognosis of root canal therapy. The purpose
of placing an apical plug is to establish an effective
barrier between the root canal and the periapical
tissues. The sealing ability of the apical plug in this
case was important because the structure of the apical
barrier might have been defective. MTA as a root end
filling material provides a superior apical seal than
62
materials such as amalgam, IRM, gutta-percha, and
Super EBA12. Torabinejad advocated a 3~4 mm
thickness of MTA for endodontic surgical techniques
with a class I preparation13. And studies of the effect
of the thickness of MTA on the sealing ability in vitro
showed that 4 mm is most adequate for MTA as a
root end filling material14.
Apical closure can take different forms: there
might be a complete or an incomplete hard tissue
barrier at the tip of the root or a few millimeters short
of the radiological apex15. In this case, the apical
barrier formed 2 mm short of the root apex. If the
barrier had broken, full-length obturation would have
led to open apex again. The canal space was
obturated superior to the barrier, and follow-up
continued. A crown and post restoration were not
recommended in this case because of the weak
structure of the root. We filled the access cavity with
composite resin.
Despite the serious damage to the root by
external root resorption, non-surgical root canal
therapy arrested the external root resorption and
regenerated the periapical tissue. This is a good result
which we would like to achineve in any case of
apexification. The outcome of treatment also depends
on the diagnosis and the treatment procedures
performed.
REFERENCES
1. Benenati FW. Root resorption: Types and treatment. Gen
Dent, 45: 42-45, 1997.
2. Andreasen JO AF. Textbook and color atlas of traumatic
injuries to the teeth. Mosby, St. Louis, 1994.
3. Lee SJ, Monsef M, Torabinejad M. Sealing ability of a
mineral trioxide aggregate for repair of lateral root
perforations. J Endod, 19: 541-544, 1993.
4. Torabinejad M, Rastegar AF, Kettering JD, Pitt Ford TR.
Bacterial leakage of mineral trioxide aggregate as a root-end
filling material. J Endod, 21: 109-112, 1995.
5. Torabinejad M, Higa RK, McKendry DJ, Pitt Ford TR. Dye
leakage of four root end filling materials: Effects of blood
contamination. J Endod, 20: 159-163, 1994.
6. Hayashi M, Shimizu A, Ebisu S. Mta for obturation of
mandibular central incisors with open apices: Case report. J
Endod, 30: 120-122, 2004.
7. Bakland LK. Root resorption. Dent Clin North Am, 36: 491507, 1992.
8. Lee YL, Lee BS, Lin FH, Yun Lin A, Lan WH, Lin CP.
Effects of physiological environments on the hydration
behavior of mineral trioxide aggregate. Biomaterials,
25 :787-793, 2004.
9. Kleier DJ, Barr ES. A study of endodontically apexified teeth.
Chin Dent J 2005‧Vol 24‧No 1
Treatment of external root resorption
Endod Dent Traumatol, 7: 112-117, 1991.
10. Chosack A, Sela J, Cleaton-Jones P. A histological and
quantitative istomorphometric study of apexification of
nonvital permanent incisors of vervet monkeys after repeated
root filling with a calcium hydroxide paste. Endod Dent
Traumatol, 13: 211-217, 1997.
11. Cox CF, Subay RK, Ostro E, Suzuki S, Suzuki SH. Tunnel
defects in dentin bridges: Their formation following direct
pulp capping. Oper Dent, 21: 4-11, 1996.
12. Torabinejad M, Watson TF, Pitt Ford TR. Sealing ability of a
mineral trioxide aggregate when used as a root end filling
Chin Dent J 2005‧Vol 24‧No 1
material. J Endod, 19: 591-595, 1993.
13. Torabinejad M, Chivian N. Clinical applications of mineral
trioxide aggregate. J Endod, 25: 197-205, 1999.
14. Valois CR, Costa ED, Jr. Influence of the thickness of
mineral trioxide aggregate on sealing ability of root-end
fillings in vitro. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod, 97: 108-111, 2004.
15. Morabito A, Defabianis P. Apexification in the endodontic
treatment of pulpless immature teeth: Indications and
requirements. J Clin Pediatr Dent, 20: 197-203, 1996.
63
W.P. Chen, B.S. Lee and C.P. Lin.
Chin Dent J 2005‧Vol 24‧No 1
64