cyst of thr jaws

DIAGNOSIS AND TREATMENT OF CYSTS OF THE JAWS

Definition of a Cyst

  • A cyst is defined as a pathologic cavity or sac within hard or soft tissues, which may contain fluid, semi-fluid, or gas.

  • It can be lined by:

    • Epithelium

    • Fibrous tissue

    • Occasionally neoplastic tissue

  • Cysts do not contain pus unless they become secondarily infected.

Classification of Cysts

  • Cysts can be classified into two major categories:

    • Intra-osseous cysts

    • Soft tissue cysts

Intra-osseous Cysts

Epithelial Cysts

  • Odontogenic Origin

    • Developmental Cysts:

    • Primordial cysts (keratocyst)

    • Dentigerous (follicular) cyst

    • Lateral periodontal cyst (includes lateral botryoid odontogenic cyst)

    • Calcifying odontogenic (Gorlin) cyst

    • Inflammatory Cysts:

    • Radicular cyst (apical/lateral periodontal)

    • Residual cyst

Non-Odontogenic Cysts

  • Fissural Cysts:

    • Median mandibular cyst

    • Median palatal cyst

    • Globulomaxillary cyst

  • Incisive Canal Cysts:

    • Nasopalatine duct or median anterior maxillary cysts

Non-Epithelial Cysts

  • Solitary Bone Cyst

  • Aneurysmal Bone Cyst

  • Stafne's Bone Cavity

  • Cysts of the Maxillary Antrum:

    • Surgical ciliated cyst of maxilla

    • Benign mucosal cyst of the maxillary antrum

Soft Tissue Cysts

Odontogenic Soft Tissue Cysts

  • Gingival cysts in adults and newborns

Non-Odontogenic Soft Tissue Cysts

  • Anterior median lingual cyst

  • Nasolabial cyst (or nasoalveolar cyst)

  • Retention Cysts:

    • Salivary gland cysts (e.g., Mucocele, Ranula)

Developmental/Congenital Cysts

  • Dermoid and epidermoid cysts

  • Lymphoepithelial cyst (cervical/intraoral)

  • Thyroglossal duct cyst

  • Cystic hygroma

Parasitic Cysts

  • Hydatid cysts

  • Cysticercosis

Heterotropic Cysts

  • Oral cysts associated with gastric or intestinal epithelium

Odontogenic Cysts

  • Most Frequent Cysts

    • The radicular cyst is the most common type.

  • Origins:

    • Arise from epithelial remnants of tooth formation:

    • These cysts are particularly found in tooth-bearing areas of the jaws.

    • Benign in nature; malignant changes are rare.

Non-Odontogenic Cysts

  • Thought to arise from the epithelial remnants from fusion processes during embryonic development.

  • Examples include aneurysmal and solitary bone cysts, which are categorized as non-epithelial lined.

  • New theories suggest many of these lesions may be odontogenic or of respiratory origin.

Clinical Presentation

  • Cysts are often slow-growing and asymptomatic, discovered inadvertently during dental check-ups or radiographic imaging.

  • Without treatment, these cysts can grow, affecting adjacent teeth and structures, leading to pathological fractures.

  • Expansion of the jaws is typically noticed radiographically.

  • Clinical signs include:

    • Absence of a tooth suggesting a dentigerous cyst in youth.

    • Carious or discolored teeth indicative of apical periodontal cysts.

    • Tilting of tooth crowns due to cyst-driven displacement.

    • Palpation may reveal smooth, hard swelling or, in infected cases, painful swellings with discharging sinuses.

    • Percussion may produce a dull sound over solitary bone cysts.

Pathogenesis of Cysts

Cyst Initiation

  • Initiated by the proliferation of the epithelial lining leading to cavity formation.

  • Expansion results in cyst enlargement, particularly in epithelium-lined cysts.

  • Little is known regarding bone cyst formation and enlargement.

Unknown Stimuli

  • The exact stimulus for cyst formation is unknown.

  • Infections may contribute but individuals may have a predisposition due to factors like:

    • Dental lamina, enamel organ, basal cell extensions of oral epithelium, reduced enamel epithelium (REE), and remnants of Malassez (CRM).

Factors Responsible for Cyst Formation

  • The process continues irrespective of cyst type and origin. The enlargement is driven by:

    • Proliferation of epithelial lining

    • Fluid accumulation in the cyst cavity

    • Bone resorption

Mechanisms of Cyst Enlargement

  • Increase in content volume

  • Surface area increase via epithelial proliferation

  • Bone resorption and soft tissue displacement

  • Factors causing cyst content increase:

    • Mucus secretion from lining leading to mucus accumulation.

    • Inflammatory cysts affected by infection, where inflammatory cells release co-factors (e.g., lymphokines, osteoclast activating factors).

    • Increased cyst fluid hyperosmolarity leads to fluid draw from surrounding tissues.

Clinical Presentation of Growth and Symptoms

  • Initially, cysts are discovered via imaging before visible expansion. When expansion appears, smooth, rounded jaw bone enlargement should raise suspicion.

  • Changes in denture fit, absence of teeth, dental cariousness, and crown tilting suggest underlying cysts.

  • An infected cyst manifests as painful swellings with potential discharge.

  • Specific presentations related to types of cysts include:

    • Dentigerous cysts associated with impacted teeth.

    • Odontogenic keratocysts typically presenting in lower molar regions.

    • Residual cysts following tooth extraction, displaying unilocular radiolucency without a visible tooth.

Diagnostic Modalities

  • Radiographic examinations are crucial for assessing cysts.

    • Periapical Radiographs: Clearly depict small cystic lesions.

    • Occlusal Films: Reveal palatal bone destruction and expansion in mandible.

    • Extra-oral Radiographs: Help evaluate the extent of lesions and damage to structures (e.g., mandibular views, orthopantomographs).

  • CT Scans: Useful for multi-cystic lesion assessment and differential diagnoses.

  • Aspirational Techniques: Aid in diagnosis by distinguishing various cystic and tumorous conditions.

  • Biopsy: Recommended for large cysts or in cases of diagnostic uncertainty.

Treatment Approaches

Reasons for Treatment

  • Cysts may grow larger and become infected.

  • They can lead to jaw weakness and fractures.

  • Unpredictable changes may arise.

  • Cysts may prevent tooth eruption.

Basic Methods of Treatment

  1. Marsupialization (decompression)

    • A surgical window is created in the cyst wall to evacuate contents, decreasing pressure and prompting shrinkage.

  2. Enucleation

    • Complete removal of the cyst lining (may include packing or closure techniques).

Marsupialization Techniques

  • Indications:

    1. Young patients with developing teeth to avoid damage.

    2. Cysts near vital structures that risk fistula formation or damage.

    3. Eruption requirements of displaced teeth.

    4. Large cysts risking pathological fractures benefit from limited opening.

    5. When vitality of adjacent teeth is critical.

Enucleation Techniques

  • Enucleation allows closure with mucoperiosteal flap, with healthy tissue filling the cavity.

  • Indications:

    • Odontogenic keratocysts, recurrence of lesions.

    • Provides quick healing, improved post-operative care, and thorough examination of the cyst.

Complications of Cystic Lesions

  • Potential issues include:

    • Pathological fractures

    • Preoperative infections

    • Post-operative wound dehiscence

    • Loss of tooth vitality

    • Neuropraxia in infected cysts

    • Recurrence of cystic lesions

    • Risk of malignant transformations or lesions.

Types of Odontogenic Cysts

Apical or Radicular Cysts

  • Commonly found at the apex of involved teeth and account for a significant percentage of dental cysts.

  • Often linked to non-vital rooted teeth and may display slow growth.

Residual Cysts

  • Develop from remnants following tooth extraction.

Lateral Periodontal Cysts

  • Asymptomatic and typically identified radiographically between roots of teeth, with adjacent teeth vital.

Dentigerous Cysts

  • Account for a significant portion of dental cysts, linked to the dental follicle at eruption sites, with common instances in the mandibular third molar region and maxillary canine area.

Eruption Cysts

  • Present as soft swellings during tooth eruption, commonly seen in children.

Gingival Cysts

  • Found in newborns and adults, treated with excision if persistent.

Odontogenic Keratocysts

  • Now classified as keratocystic odontogenic tumors, aggressive and prone to recurrence.

Calcifying Epithelial Odontogenic Cysts

  • Rare aggressiveness and potential for recurrence, initially managed with enucleation.

Types of Non-Odontogenic Cysts

Fissural Cysts

  • Discussed under embryonic fusion contexts despite later findings indicating an odontogenic origin.

Nasopalatine Cysts

  • Arising from nasopalatine ducts; common in adults, requiring careful differentiation from other lesions.

Stafne Cysts

  • Considered static bone cysts beneath molars, often containing salivary or lymphoid tissue.

Aneurysmal Bone Cysts

  • Presenting as lesions often requiring surgical intervention; can recur.

Solitary Bone Cysts

  • Usually found incidentally, may resolve without intervention yet larger lesions require curettage.

Conclusion

  • Comprehensive understanding of cyst types, management strategies, and potential complications is essential for effective treatment of cystic lesions in the jaws.