Key words:
Endodontic treatment - internal root replacement resorption - internal root resorption
INTRODUCTION
Clinically, internal root resorption is a rarely seen condition.[1] Histologically, a part of the pulp tissue inside the root canal shows resorptive
inflammatory changes involving dentin resorbing cells (odontoclasts) in the resorption
lacunes. Predentin and odontoblasts were suggested as a protective layer against the
internal resorption, inhibiting dentinoclast adherence to dentin tissue. If the pulp
is not completely necrotized by advancing coronal infection, internal resorptive activity
progressively resorbs the root canal dentin and eventually perforates the cementum.[2]
[3]
Two types of internal resorption were defined on the basis of histological observations
as follows: internal inflammatory resorption (IIR) and internal replacement resorption
(IRR). Radiographically, the IIR displays a clear, oval shaped radiolucent area around
the root canal. In the IRR cases, an irregular enlargement of the root canal with
the radiological appearances of a fuzzy material resembling the bone tissue might
be observed.[2]
[3]
For treatment of perforating internal root resorption cases, mineral trioxide aggregate
(MTA) might be preferred to fill the root defect and the canal.[4]
[5]
[6]
[7] The removal of resorptive inflammatory tissue with the surgery and filling of root
defect with MTA might be another treatment approach for the perforating cases.[8]
[9]
This case report presents orthograde management of a case of perforating IRR using
MTA as a root canal filling.
CASE REPORT
A 20 year old female presented to the Department of Endodontics, School of Dentistry,
İstanbul University, with discomfort in her maxillary right central tooth. She reported
a trauma on the right central tooth when was a child, causing a crown fracture.
A sinus tract was seen clinically on the midfacial attached gingiva of the right central
tooth. A composite resin restoration was present on the tooth. Radiographic examination
showed the presence of an irregular enlargement of the canal at the middle third root
level. The enlarged part of the canal appeared to be filled by the fuzzy hard tissue
material [Figure 1a]. The apical part of the root canal appeared to be obliterated, and no signs of apical
pathosis were detected at the radiographies. An irregular rarefaction was present
at the distal middle root wall, showing appearances of perforating internal root resorption.
The patient declined the recommendation for cone beam computed tomography diagnosis
of the tooth.
Figure 1: (a) Preoperative radiography of the case showing internal replacement resorption.
Note the appearance of irregular enlargement at the middle third of the canal that
was filled with a fuzzy material resembling the bone-like tissue. (b) Calcium hydroxide
medication at 1-month follow-up. (c) After canal filling with mineral trioxide aggregate.
Note the gaps between mineral trioxide aggregate and the resorbed root walls (arrows)
Written consent was obtained from the patient. The patient’s medical history was noncontributary.
Following local infiltration anesthesia (Ultracaine D S, Sanofi, Kırklareli, Turkey)
and the placement of a rubber dam, the root canal was accessed. Working length determination
with an apex locator (Propex II, Dentsply, US) showed beyond the foramen signals when
the file tip was at the middle third root level. Working length was determined with
a K file (21 mm) with digital periapical radiography. After the copious irrigation
with saline solution, a conservative filing was applied to the canal walls. Bleeding
was present from the canal during instrumentation. The canal was medicated with calcium
hydroxide (CH) mixed with saline (Sultan Dental, NY, US) using a lentulo. The cavity
was sealed with a temporary filling (Coltosol, Vigodent, Bonsucesso, Brazil). Following
copious irrigation with 5% NaOCl, CH powder–saline mixture was renewed after a week.
The healing of sinus tract was observed at the 1 month visit. The exudation from the
canal was continuing, and CH was placed into the canal after the irrigation [Figure 1b]. CH dressing was renewed two times in 2 months due to the exudation in the canal.
At the 3 month visit, white MTA (ProRoot MTA, Dentsply, TN, US) was prepared according
to the manufacturer’s recommendations and filled incrementally to the canal orifice
with vertical condensation using the pluggers. Intraoperative radiographies revealed
that MTA filled the canal and the resorption defect. A wet cotton pellet was put on
the MTA, and the cavity was sealed with the temporary restorative material. After
3 days, the cavity was restored using an anterior composite resin filling (Supreme,
3M ESPE, Dental Products, MN, USA), [Figure 1c].
At the time of the 6 and 12 month follow ups, organization of the periradicular tissues
around the perforation site and progressive deposition of hard tissue between the
MTA and the defect margins were seen, radiographically. The patient missed the 2 year
follow up. An orthodontist phoned for the consultation of the orthodontic treatment
that was planned for the patient. During the 4 year follow up examinations, the tooth
was free of endodontic and periodontal symptoms. Radiographically, the gaps were seen
as completely repaired with the deposition of hard tissue [Figure 2a]. After the completion of a year long orthodontic treatment, all incisors were restored
with full esthetic ceramic crowns by a prosthodontist due to the patient’s complaints
about the occurrence of discoloration in the tooth [Figure 3a] and [b]. The prosthodontist reported that a fiber post was bonded to the canal, and a composite
core was built up. At 6 year follow up radiographs, the healing with hard tissue repair
resembling a barrier on the MTA and the organization of periodontal membrane adjacent
to this hard tissue barrier were seen [Figure 2b].
Figure 2: (a) Four-year follow-up radiograph. (b) Six-year follow-up radiograph showing a thick
and complete hard tissue barrier on mineral trioxide aggregate (arrow)
Figure 3: (a) Mineral trioxide aggregate discoloration in the crown. (b) Esthetic appearance
after prosthetic restoration
DISCUSSION
The clinical manifestations of the presented case herein appeared that the tooth was
showing an IRR with perforation to the surrounding tissues. The case featured an irregular
enlargement in the middle third of the root canal, which was filled with a fuzzy material
resembling the radiographic appearances of bone.
Histologically, the resorptive activity of odontoclasts in IRR cases causes defects
in the intraradicular dentin tissue concomitant with the deposition of metaplastic
bone like hard tissue in some areas of the defect. As a result, an irregularly shaped
resorption defect occurs in the dentin walls of the affected canal region.[2]
[3]
Patel et al.[2] noted that the ultimate treatment modality for the treatment of perforating IR cases
is the conventional endodontic therapy. Nilsson et al.[3] suggested the surgical approach with the use of MTA or calcium silicate cements
for the filling as a second intention in cases in which it is not possible to manage
the lesion through the canal. Altundasar and Demir[8] treated successfully perforating internal resorption cases using MTA and periodontal
surgery with graft materials in single treatment sessions. The long term successful
clinical and radiological results of this case favor nonsurgical endodontic management
for the perforating internal resorption cases. The surgical approach in the treatment
of perforating internal resorptions might be used when an excessive extrusion of the
MTA filling occurs during the root canal filling.
Long term (3 months) CH medication was used in the treatment of this case because
intracanal exudation was present at the patient’s 2 month visit. The advantages of
long term CH dressings are its antibacterial effect on the intracanal bacteria and
its possible necrotizing effect on the internal inflammatory resorptive tissue, which
is similar to its coagulation necrosis effect on the exposed pulp tissue due to its
high pH.[9] However, long term CH medication may cause a significant decrease in the fracture
resistance of teeth roots.[9]
The disadvantages of orthograde MTA canal filling in perforating internal resorption
cases might be coronal discoloration, extrusion from the perforation, and inadequate
marginal adaptation around the root defects. The coronal discoloration due to the
MTA canal filling was seen in this case.
The advantages of MTA are good sealing ability, biocompability, physical durability,
and low grade and long term CH release. MTA was shown to allow proliferation of periodontal
cells and cementoblast over itself in animal and cell culture studies.[10],[11] The deposition of a hard tissue around the MTA filling in the perforation defect
was present initially at the 6 month follow up radiographies of the present case.
Furthermore, a hard tissue barrier was evident at 4 and 6 years, repairing the defected
root surface. This hard tissue barrier might be cementum, proliferating from the adjacent
root surfaces. One year orthodontic treatment did not appear to cause an adverse effect
on the tooth root in the present case.
Financial support and sponsorship
Nil.
