resorption 1
TRANSCRIPT
PATHOLOGICAL TOOTH RESORPTION
DEFINITION
According to the American association of Endodontics in 1944,
(Glossary – Contemporary Terminology for Endodontics) resorption is
defined as “A condition associated with either a physiologic or a pathologic
process resulting in the loss of dentin, cementum or bone.”
Root-resorption is the resorption affecting the cementum or dentin of the
root of tooth.
CLASSIFICATION OF RESORPTION
Pathologic tooth resorption is seen in both deciduous as well as
permanent teeth due to underlying pathology.
a. Internal Resorption
Root canal replacement Resorption
Internal inflammatory Resorption
b. External Resorption
Surface Resorption
Inflammatory Resorption
Replacement Resorption
Dentoalveolar ankylosis
MECHANISM OF TOOTH RESORPTION
Resorption of hard tissue takes place as two events. First, there is the
degradation of inorganic crystal structures – hydroxyapatite, after which, the
degradation of the organic matrix takes place.
Degradation of the Inorganic Crystal Structure
Degradation of the Inorganic Structure is initiated by the creation of
an acidic pH of 3 to 4.5 at the site of resorption. This is created by the
polarize de proton pump which is produced within the ruffled border of the
clastic cells. Below the pH of 5, the dissolution of hydroxyapatite is found to
occur.
Enzymes carbonic anhydrase II which catalyses the conversion of CO2
and H2CO3 intracellularly also maintains an acidic environment at the site of
resorption which is a readily available source of H+ ions. The enzyme acid
phosphatase also favors the resorption process.
CO2 + H2O H2CO3
H2CO3 H+ + HCO3 –
Degradation of the Organic Matrix
Three main enzymes involved in this process are collagenase, matrix metallo
proteinases (MMP) and cysteine proteinases
Enzymes Involved in Degradation of Organic Matrix
1. collagenase
2. matrix metallo proteinases (MMP)
3. Cysteine proteinases
Collagenase and MMP act at a neutral or just below neutral pH – 7.4.
They are found more towards the resorbing bone surfaces where the pH is
near neutral, because of the presence of the buffering capacity of the resorbing
bone salts. MMP is more involved in odontoblastic action. Cysteine
proteinases are secreted directly into the osteoclasts into the clear zone via the
ruffled border. Cysteine proteinases work more in an acidic pH and near the
ruffled border, the pH is more acidic.
Inhibitory Mechanisms of Resorption
Cementum
The innermost layer of cementum is lined by the cementoid tissue and
the cementoblasts. The cementoid is less mineralized and so it is more
resistant to resorption. Clastic cell are attracted or can attach themselves
only to mineralized tissues. The innermost layer of cementum is a highly
calcified layer, acts as a barrier between the dentinal tubules and the
sharpey’s fibers. They do not allow the passage of toxic products or
microorganisms under normal circumstances. Cementoblasts favor
cementum formation. Continuity of root cementum is an important factor to
be taken into consideration in various pathologies of resorption.
Dentin
Predentin layer of dentin, the just formed dentin, lined by odontoblasts
favor dentin deposition. Wedenberg et al has demonstrated it as an anti-
invasive factor in dentin.
According to silva et al, dentin contains numerous polypeptide
signaling molecules which may affect the healing and resorption of dental
and periodontal tissues.
FACTORS REGULATING TOOTH RESORPTION
Systemic factors
Parathyroid hormones (PTH) favor resorption. They stimulate osteoclasts;
favor the formation of multinucleated giant cells.
1,2,5 Dihydroxy Vit D3 increases the resorption activity of the osteoblasts.
Calcitonin inhibits the resorption by suppressing the osteoclastic
cytoplasmic mobility of the ruffled border.
Local Factors
These are secreted from inflammatory cells and osteoblasts as a result
of stimulation by bacteria, tissue breakdown products and cytokines
themselves.
Factors Regulating Tooth Resorption
Local factors systemic factors
Macrophage colony Parathyroid hormone
Stimulating factor (M-CSF)
Interleukin 6 1,2,5 dihydroxy Vit D3
Interleukin 1 calcitonin
TNF – alpha
Prostaglandin – PGE 2
Bacteria and toxins
Internal Resorption
According to shafer, “ internal resorption is an unusual form of tooth
resorption that begins centrally within the tooth, apparently initiated in most
cases by a peculiar inflammation of the pulp”. It is characterized by oval
shaped enlargement of root canal space. It is usually asymptomatic and
discovered on routine radiographs. Internal resorption may progress slowly,
rapidly or intermittently with period of activity and inactivity.
Etiology
Long standing chronic inflammation of the pulp
Caries related pulpits
Traumatic injuries
a. Luxation injuries
Iatrogenic injuries
a. Preparation of tooth for crown
b. Deep restorative procedures
c. Application of heat over the pulp
d. Pulpotomy using Ca (OH)2
Idiopathic
Clinical Features of Internal Resorption
Usually asymptomatic until it perforates the root and communicates
with periodontium.
Common in maxillary central, but can affect any tooth
Spreads rapidly in primary teeth
Pathagnomonic feature is pink spot appearance of tooth which
represents the hyperplasic vascular pulp tissue showing off through
crown of tooth.
Radiographic Features
The typical radiographic appearance is smooth widening of root canal
wall.
Types of Internal Resorption
Clinically, there are two types of internal resorptions:
a. Root canal replacement resorption.
b. Internal inflammatory resorption
Root canal replacement resorption
(Metaplastic Resorption)
Resorption of dentin and subsequent deposition of hard tissues are
found that resembles bone or cementum or osteodentin, but not dentin. They
represent areas of destruction and repair. This occurs mainly due to low
grade irritation of pulpal tissue.
Etiology
Trauma, extreme heat to the tooth, chemical burns during pulpotomy
procedures may initiate the root resorption.
Radiographic features:
Radiographically the tooth shows enlargement of the canal space. This
space latter gets engorged with a material of radiopaque appearance giving
the expression of hard tissue.
Histopathology;
Osteodentin type of tissue is found in the place of pulp.
INTERNAL INFLAMMATROY RESORPTION
Radiographic features:
It presents round or ovoid radiolucent area in the central portion of the
tooth with smooth well defined margins. The defect does not change its
relation to the tooth, when the range is projected form an angulation.
Management of internal root resorption
Treatment options in teeth with internal resorption
Without perforation –endodontic therapy
With perforation
a. Non-surgical: Ca (OH) 2 therapy –obturation
b. Surgical
i. Surgical flap
ii. Root Resection
iii. Intentional replantation
MANAGEMENT FOR PERFOARTING INTERNAL RESORPTION
a. Non-Surgical Repair
Indications
Non surgical repair is indicated in following cases:
i. When the defect is not extensive.
ii. When defect is apical to epithelial attachment.
iii.When hemorrhage can be controlled.
The intracanal calcium hydroxide dressing is placed and over it
temporary filling is placed to prevent interappointment leakage. Patient
recalled after three months for replacement of calcium hydroxide dressing
and for radiographic confirmation of the barrier formation at the perforation
site. After the barrier is formed, the canal is obturated with gutta-percha as in
the non perforating internal resorption.
b. Surgical repair
Indication of surgical repair:
i. Surgical flap
ii. Root resections
iii.Intentional replantation
If the calcium hydroxide treatment is unsuccessful or not feasible,
surgical of the defect should be considered.
1. Surgical Flap:
Here the defect is exposed to allow good access. The resorptive defect
is curetted, cleaned and restored. The restoration of the defect can be done
using an alloy, composite, glass ionomer cement, super EBA or more
recently MTA. Family the obturation is done using gutta –percha.
2. Root resection:
If the resorbed area is located in the radicular third, root may be
resected coronal to the defect and apical segment is removed afterwards.
Following root resection retrofilling is done.
If done root of a multirooted tooth is affected, root resection may be
considered based on anatomical, periodontal and restorative parameters.
4. Intentional replantation:
If the perforating resorption with minimal root damage occurs in an
inaccessible area, intentional replantation may be considered.
External root resorption:
External root resorption is initiated in the periodontium and in effects
the external or lateral surface of the root.
Classification:
Surface resorption
External inflammatory root resorption
Replacement resorption
EXTERNAL INFLAMMATORY ROOT RESORPTION
Etiopathology
Injury of irritation to the periodontal tissues where the inflammation is
beyond repair
Orthodontic tooth movement using excessive forces
Trauma from occlusion –leading to periodontal inflammation
Avulsion and luxation injuries
Pressure resorption occurring from pressure exerted by tumors, cysts
and impacted teeth.
Clinical Features
Patient gives history of trauma – recent or past
Necrotic pulp/irreversible pulpitis is frequently seen.
Tooth is usually mobile in most of the cases.
Inflammation of the periodontal tissues is commonly seen.
Percussion sensitivity is present.
Pocket formation may or may not be there. If the resorption area
communicates with the gingival sulcus, it can lead to pocket
formation.
Radiographic Features
Bowl like radiolucency with ragged irregular areas on the root surface
is commonly seen in conjunction with loss of tooth structure and alveolar
bone.
Treatment
If the sustaining infection is pulpal, root canal therapy has been shown
to be a very successful means of treating inflammatory resorption.
Replacement Resorption
This is similar to ankylosis, but there is presence of an intervening
inflamed connective tissue, always progressive and highly destructive.
Etiopatho
genesis
Replacement resorption usually occurs after a severe dental injuries
like intrusive luxation or avulsion injuries resulting in drying and death of
periodontal ligament cells.
Clinically
Replacement resorption is usually asymptomatic. Infra occlusion,
incomplete alveolar process development (if the patient is young), and
prevention of normal mesial drift are commonly seen. Pathagnomonic
feature is immobility of affected tooth and a distinctive metallic sound on
percussion.
Diagnosis
Diagnosis can be made from clinical evaluation and radiographic
observation.
Treatment
Currently there is no treatment offered fro replacement resorption. It
may be possible to slow the resorptive process by treating the root surface
with fluoride solution prior to replantation.
Dentoalveolar Ankylosis
Dentoalveolar ankylosis is the union of tooth and bone with no
intervening connective tissue.
Etiopathology
Traumatic injuries to teeth.
Clinical features:
A tooth with dentoalveolar ankylosis shows:
Lack of mobility
Dull metallic sound on percussion (may be evident even before the
appearance of the radiograph)
Infraocculasion because of lack of the normal growth of the alveolar
process.
Lack of mesial drift.
Radiogr
aphic Features
Radiographically one can observe the moth eaten appearance with
irregular border, absence of periodontal ligament and lamina dura.
Treatment of ankylosis.
No treatment is required for dentoalveolar ankylosis.
Prevention
Immediate replantation
Proper extraoral storage to prevent dehydration
Cervical root resorption (extra canal invasive resorption)
According to cohen, it is the type of inflammatory root resorption
occurring immediately below the epithelial attachment of tooth.
Etiology
Orthodontic treatment
Trauma
Bleaching of non vital teeth
Periodontal treatment
Bruxism
Idiopathic
Clinical Features of Cervical Root Resorption
Initially asymptomatic
Pulp vital in most cases
Normal to sensitivity tests
Long standing cases give pink spot appearance clinically,
misdiagnosed as internal resorption but confirmed radiographically
In due course, it spreads laterally along the root, i.e., apical and
coronal direction “enveloping” the root canal.
FRANK’S CLASSIFICATION OF CERVICAL ROOT RESORPTION
Supraosseous-coronal to the level of alveolar bone
Intraosseous-not accompanied by periodontal breakdown
Crestal-at the level of alveolar bone
RADIOGRAPHIC FEATURES
Radiographically there will be moth eaten appearance with intact
outline of the canal.
TREATMENT
A traditional approach is to treat the tooth endodontically first followed
by repair of the resorbed area either from an internal approach or an
external one.
Another treatment is surgically exploring the resorbed lacuna and
curetting the soft tissue from the defect which can then be prepared for
restoration. This procedure is more conservative.If pulpal symptoms
develop later, root canal theraphy can be performed.
TRANSIENT APICAL BREAKDOWN
It is a temporary phenomenon in which the apex of the tooth displays
radiographic appearance of resorption followed by surface resorption. Repair
takes place within a year. It is commonly seen in mature teeth with completely closed apex.
ETIOLOGY
Moderate injuries such as
-Subluxation
-Extrusion
-Lateral luxation
-Infections
-Orthodontic treatment
-Trauma from occlusion.
TREATMENT
No treatment is recommended.
CONCLUSION
Tooth resorption is a perplexing problem where the etiologic factors are
Vague and less clearly defined. Early diagnosis and prompt treatment are the
key factors which determine the success of the treatment.