10 Types of Periapical Radiolucencies: Diagnosis, Causes, and Treatment Explained

Periapical Radiolucencies

That are truly in contact with the apex of the tooth

• Pulpoperiapical radiolucencies:
  • Periapical granuloma
  • Radicular cyst
  • Periapical scar
  • Periapical abscess
  • Surgical defect
  • Osteomyelitis
  • Hyperplasia of sinus mucosa
  • Periapical cemental dysplasia
  • Acute apical periodontitis
  • Traumatic bone cyst
  • Dentigerous cyst
  • Non-radicular cyst
  • Benign and malignant tumors, including secondary metastatic deposits
  • Giant cell granuloma
  • Lymphoreticular tumors of bone.

“Periapical Radiolucencies Diagnosis”

False (anatomic Periapical Radiolucencies)

Produced by anatomic cavities or lytic bony lesions that do not contact the apex of the tooth.

These radiolucent shadows are shifted from the periapex by taking additional periapical radiographs at different angles:

• Mental foramen
• Focal osteoporotic bone marrow defects
• Dental papilla
• Incisive foramen
• Maxillary sinus

About 30–60% of bone loss must have occurred for a change to be detected on radiographs.

Periapical Radiolucency

Periapical Granuloma

It is a localized mass of chronic granulation tissue formed in response to infection.

Pathogenesis

• The physiological response to traumatic, microbial and chemical stimulation of the pulp is inflammation.
• Edema is an inherent component of inflammation.
• Edema produces compression of apical blood vessels, causes ischemic pulpal necrosis and prevents blood flow necessary for healing and repair.
• This leaves a source of necrotic, toxic material with in the pulp chamber that eventually diffuse through the apical foramina.
• Induces inflammation of adjacent tissue.
• This periapical inflammation stimulates lysis and remodeling of periradicular bone.
• Continuous discharge of chronic irritating products from the root canal into the periapical tissue.
• This maintains a low-grade inflammation which induces a vascular inflammatory response.
• Periapical granuloma is the result of successful attempt by the periapical tissues to neutralize the toxic products that are escaping from the root canal.

“Differential Diagnosis Of Periapical Radiolucencies”

Periapical Radiolucencies Clinical Features

• The tooth is often asymptomatic.
• Previous history of prolonged sensitivity to heat or cold
• Deep caries, a deep restoration or history of trauma.
• Tooth is oftn tender to percussion (because the apical PDL contains inflmed granulation tissue).
• Fail to react to thermal or electrical stimulation (because the pulp is nonvital).

Periapical Radiolucencies Radiographic Features

• Earliest sign: Thickened PDL space at the root apex.
• Well-circumscribed radiolucency: somewhat rounded and surrounding the apex of the tooth.
• Thin radiopaque hyperostotic border.

Periapical Radiolucencies Microscopic Features

• Proliferating endothelial cells, capillaries, young firoblasts, collagen, chronic inflammatory cells, lymphocytes, plasma cells, macrophages.
• Nests of odontogenic epithelium, Russell bodies, foam cells, cholesterol cleft.
• More inflmmation is seen in center of the lesion.
• At periphery: Fibrosis (healing) is seen.

Types Of Periapical Lesions

Periapical Radiolucencies Treatment

• Extraction of the involved tooth.
• Root canal therapy (with or without apicoectomy).
• If left untreated, it may undergo transformation to periapical cyst.

“Periapical Radiolucencies Treatment”

Periapical Radiolucencies Periapical (Radicular) Cyst

• 2nd most common pulpoperiapical lesions.
• About 6–17% to 25.9 percent of all pulpo-periapical lesions.
• Inflmmatory cyst.
• Origin in cell rest of malassez, PDL cells which are remnants of Hertwig root sheath.
• About 58% of lateral incisors are involved.
• Deciduous teeth—molars are involved.
• Diameter > 1.6 cm.
• Expansion of cortical plates.
• Initially, bony hard to palpation.
• Later, it becomes rubbery and fluctuant: the cortical plate becomes thinned (Crackling sound, crepitus).

Periapical Radiolucencies Microscopic Features

• Lumen surrounded by epithelial lining on a connective tissue wall.
• Periphery: Fibrous.
• Inner region: granulation tissue, chronic inflmmatory cells, foam cells, Russell bodies, cholesterol clefts. Aspiration—straw-colored flid.
• Cholesterol cleft—shiny granules.

Periapical Radiolucencies Differential Diagnosis

• Periapical granuloma
• Periapical scar
• Periapical cemento-osseous dysplasia
• Traumatic bone cyst
• Malignancy.

Periapical Lesion Diagnosis

Periapical Radiolucencies Management

• Root canal treatment.
• 1–3 months recall.
• If extraction is indicated—periapical area should be curetted and microscopic examination should be done.
• Large radicular cysts—surgical enucleation, marsupialization, decompression.
• Sequential postsurgical radiographs should be taken to ensure that lesion is regressing.
• Average healing time for cyst of > 10 mm diameter is 2½ years.
• Incomplete removal—formation of residual cyst.

“Periapical Radiolucencies Vs Other Lesions”

Periapical scar

• About 2–5% of all periapical radiolucent lesions.
• Composed of dense firous tissue.
• Situated at periapex of pulpless/endodontically treated tooth.
• It represents a previous periapical granuloma, cyst of abscess whose healing has terminated in the formation of dense scar tissue (cicatrix) rather than bone.
• Few spindle-shaped firoblasts.
• Collagen bundles show an advanced degree of hyalinization.
• Well-circumscribed radiolucency.
• Resembles periapical granuloma or cyst but is smaller than these entities.
• Tooth is asymptomatic.
• Radiolucency remains constant in size or shrinks slightly.
• Common site—anterior region of maxilla
• No treatment is required, if asymptomatic root canal filed tooth.

Periapical Abscess

• About 2% of all pathologic periapical radiolucencies.
• Primary or neoteric abscess (acute apical periodontitis, acute periapical abscess).
• Virulent bacteria rapidly spread to the periapical tissues and cause an acute periodontitis.
• Tooth is very sensitive.
• Onset and course of the infection are so sudden that resorption of bone has not yet occurred.
• Apical inflammation forces the tooth slightly from its socket due to which there is increased PDL space around the entire root.

Microscopic Features

• Central region of necrosis containing polymorphonuclear leukocytes surrounded by an inflamed connective tissue wall.
• Chronic resolving abscess—lymphocytes, plasma cells, macrophages and granulation tissue.

Causes Of Periapical Radiolucency

“Radiographic Features Of Periapical Radiolucencies”

Periapical Radiolucencies Clinical Features

• Affcted tooth: Deep restoration, caries, resorption at the apex.
• Tooth is painful on percussion.
• High to bite.
• Does not respond to electric pulp test.
• Abscess may penetrate the cortical plate and from a space infection.

Periapical Radiolucencies Surgical Defect

• About 3% of all periapical radiolucencies.
• It is seen periapically aftr root resection procedures.
• Tooth is usually asymptomatic.
• Small depression in the mucosa over the apical area.
• Rounded, smoothly contoured and has well-defined borders.
• Usually < 1 cm in diameter.
• Periodic radiographic examination shows reduction in size of the radiolucency.

Periapical Radiolucencies Osteomyelitis

• Infection of bone involving all the three components: Periosteum, cortex and bone marrow
• Mandible is more commonly involved as compared to maxilla
• Offending tooth contains nonvital pulp, previously associated with an acute or chronic periapical abscess
• Basal bone is involved

Acute Osteomyelitis

• Similar to acute primary alveolar abscess, since onset and course is rapid and bone resorption has not occurred
• Chronic osteomyelitis
• Low-grade infection of bone
• Ifuntreated follows a protracted course ofbone destruction
• Mandible is most commonly involved
• Offnding tooth contains nonvital pulp
• Previously associated with acute or chronic periapical abscess
• Periapical radiolucency is somewhat rounded with poorly defied and ragged borders
• Such an appearance results from irregular extensions of the inflmmation and infection through marrow spaces and channels in the bone.

“Periapical Radiolucencies And Inflammation”

Microscopic Features

• Identical to that produced by chronic alveolar abscess
• Necrotic tissue containing polymorphonuclear leukocytes and regions of granulation tissue
• More dead bone (spicules with empty lacunae).

Differential Diagnosis

• Chronic alveolar abscess
• Paget’s disease

Periapical Radiolucencies Treatment

• Removal of involve tooth
• Curettage of socket
• Antibiotics
• Incision and drainage, if require
• Surgical sequestrectomy, saucerization and recontouring.

Periapical cemento-osseous dysplasia

(Periapical Cementoma, Periapical Osteofiroma)

Most common firo-cemento-osseous lesion

Reactive lesion of PDL origin

• Three stages of development
• Early (osteolytic or firoblastic) stage is radiolucent
• Intermediate stage: Radiolucent area containing radiopaque foci
• Mature stage: Well-defied solid homogeneous radiopacity surrounded by thin radiolucent border

Endodontic Lesions Causes And Treatment

“Periapical Radiolucencies And Root Canal Treatment”

Clinical Features

• Somewhat round radiolucencies with well-defied borders
• Associated teeth have vital pulp
• Blacks are more commonly affcted than whites
• About 80% lesions occur in women
• Seldom seen before 4th decade
• About 90% of lesions occur in mandible
• Most frequently involved site
• Periapical region of mandibular incisors
• Lesions may be solitary or multiple, are completely asymptomatic
• Seldom exceed 1 cm in diameter

Differential Diagnosis Of Periapical cemento-Osseous Dysplasia

• Anatomic radiolucency
• Pulpoperiapical radiolucency
  • Associated with pulp disease or pulp death
• Traumatic bone cyst: Found in a younger age group
  • Mandibular premolar or molar teeth
• Focal cemento-osseous dysplasia:
  • Mandibular premolar or molar teeth
  • Margins are not so discrete
• Cemento-ossifying firoma:
  • Occurs at apices of vital teeth
  • Younger people, premolar region
• Cementoblastoma (early stage):
  • Occurs at the periapices of the mandibular molars.
  • It characteristically extends higher or the roots.

“Periapical Radiolucencies And Endodontic Treatment”

Periapical Radiolucencies Periodontal Disease

• Advanced periodontal bone loss involving one tooth more severely than the teeth immediately adjacent to it.
• The entire bony support of the involved tooth may be destroyed, and the tooth may appear floating in radiolucency.
• Diagnosis can be made by probing the periodontal pockets. Placing gutt-percha points in the pockets to their full depths and then taking radiographs can demonstrate pocket depth relative to the root length.
• Affected teeth are quite mobile and sensitive to percussion.
• Teeth are vital, unless concomitant endodontic lesion is present.
• Treatment: Extraction
• The soft tissue most be curetted from apical region and sent for microscopic examination.

Traumatic Bone cyst

Simple/solitary Bone cyst

• False cyst of bone as it does not have an epithelial lining.
• Etiology is unknown but may be associated with trauma.
• Age: Under 20 years
• Site: Mandible, particularly the premolar/molar region above the mandibular canal, rarely anterior maxilla
• Size: Variable up to several centimeters in diameter.
• Shape: Monolocular, irregular, but the upper border arches up between the roots of the teeth producing the ‘scalloped appearance’
• Outline: Smooth and moderately well defied.
• Radiodensity: Uniformly radiolucent
• Effects: Adjacent teeth—vital with intact lamina dura minimal or no displacement, very rarely resorbed
• Minimal or no expansion of jaw:
  • Aspiration—usually fruitless, but in some cases may reveal serosanguineous fluid, small quantity of blood, or a serum-like fluid.
  • Microscopic examination—shows scanty tissue, which is loose or fibrous connective tissue containing some hemosiderin.

“Periapical Radiolucencies And Dental Implants”

Periapical Radiolucencies Differential Diagnosis

• Radicular cyst: Pulps are nonvital
• Periapical cemento-osseous dysplasia: Seldom more than 0.7cm. Occurs over 30 years of age. Predilection for lower incisors periodic radiographs show the maturational stages of radiolucent periapical cemento-osseous dysplasia. Traumatic bone cyst is larger than 1 cm under 25 years Premolar/molar area.
• Median mandibular cyst: Occurs in the midline of lower jaw associated teeth are vital causes separation of teeth. Midline of lower jaw associated with teeth are vital.

Apical Periodontitis Causes

Periapical Radiolucencies Management

The treatment of choice is to open the area surgically, establish the diagnosis of traumatic bone cyst, remove the tissue debris present, curette the walls of the bony cavity to induce bleeding. After the clot has organized, bone will fil the defect. A careful follow-up is necessary to confim healing.

Dentigerous cyst

• 2nd most common odontogenic cyst
• Pericoronal radiolucency is projected over the apex of neighboring tooth.
  • In circumferential or lateral dentigerous cyst, the radiolucency may project over the apex of the same tooth.

Nonradicular cyst

• Nonradicular cyst may be projected over the apices of teeth
• Most common are:
  • Incisive canal cyst
  • Midplatine cyst
  • Median mandibular cyst
  • Primordial cyst
• With the exception of primordial cysts, these occur in specific regions of the jaw bones.
• Changing the angle at which the radiograph is taken frequently projects the radiolucent image of the nonodontogenic cyst away from the superimposed apices, this diffrentiates it from pulpoperiapical pathologies.
• Associated teeth are vital.
• If a cyst-like radiolucency larger than 2 cm in diameter is present over the apex of a vital maxillary incisor and can be projected away from the apex by changing the horizontal angulation of a second radiograph, most likely diagnosis is incisive canal cyst.
• If a cystic area at the periapex of a maxillary fist molar on a periapical fim is shown on an occlusal film to involve the whole palate, and if all the maxillary teeth are vital, the most appropriate diagnosis is mid palatine cyst.

“Periapical Radiolucencies And Periodontal Disease”

Periapical Radiolucencies Malignant Tumor

Malignant tumors may be found as a single periapical radiolucency mimicking a more common benign lesion; early malignant lesions at the apices seldom present with features that suggest their identity. Therefore biopsy is mandatory for periapical lesions that do not respond to endodontic therapy, are surgical cases or are otherwise suspect:

• Squamous cell carcinoma
• Malignant tumor of the minor salivary glands
• Metastatic tumors
• Osteolytic sarcoma
• Chondrosarcoma
• Melanoma
• Fibrosarcoma
• Reticular cell sarcoma
• Multiple myeloma
  • Malignant periapical radiolucencies may produce the following images
• Well-defied periapical radiolucency
• Poorly defied periapical radiolucency
• Large, ragged, well-defied radiolucent tumor
• Root resorption and band-like widening of PDL spaces.

Radiographic Diagnosis Of Periapical Lesions

Periapical Radiolucencies Features

• Middle and old age
• Pain may be a feature
• Teeth may be vital
• If the tumor is advanced, there may be migration, loosening, tipping, and spreading of teeth
• Gingival bleeding
• Paresthesia or anesthesia
• Advanced lesions may show expansion of jaw
• The advanced lesions are readily recognized as malignancies. The earlier lesions present a problem
• Periodic clinical and radiographic examination
• If root resection is performed the tissue recovered from the periapical region should be sent for microscopic study.