cysts of oral cavity

Dentigerous cysts are one of the most common types of odontogenic cysts, which are derived from the dental tissues. They usually form as a result of the accumulation of fluid between the reduced enamel epithelium and the crown of an unerupted tooth. Dentigerous cysts are typically associated with the crowns of impacted, embedded, or unerupted teeth. Here is a classification of dentigerous cysts based on their origin and development:

**1. Developmental Dentigerous Cyst:**

   - This type of cyst arises from the normal development of the tooth follicle.

   - It occurs when the crown of an unerupted tooth is enclosed by the reduced enamel epithelium, which becomes fluid-filled.

**2. Inflammatory Dentigerous Cyst:**

   - An inflammatory dentigerous cyst forms due to inflammation in the follicle caused by trauma, infection, or caries near an impacted tooth.

   - Inflammation leads to the accumulation of fluid, resulting in cystic enlargement.

**3. Impacted Tooth-Associated Dentigerous Cyst:**

   - This type of cyst is directly related to the presence of an impacted tooth.

   - The cyst develops as the crown of the impacted tooth becomes enclosed by the reduced enamel epithelium, leading to fluid accumulation.

**4. Eruption Cyst (Eruption Hematoma):**

   - An eruption cyst is a type of dentigerous cyst that forms when the tooth is in the process of erupting through the oral mucosa.

   - The cyst contains blood due to the rupture of blood vessels during tooth eruption.

**5. Orthokeratinized Odontogenic Cyst (OOC):**

   - The orthokeratinized odontogenic cyst is a variant of the dentigerous cyst.

   - It is characterized by the presence of orthokeratinized stratified squamous epithelium lining the cystic cavity.

It is important to note that dentigerous cysts can be classified as either odontogenic or non-odontogenic, depending on their origin. Odontogenic cysts originate from dental tissues, while non-odontogenic cysts are not associated with dental structures. Dentigerous cysts fall under the category of odontogenic cysts as they are derived from the dental follicle surrounding an unerupted tooth. Proper diagnosis and timely treatment of dentigerous cysts are crucial to prevent potential complications and damage to adjacent structures.

**Odontogenic Keratocyst (OKC): Epidemiology, Histology, Clinical Features, and Radiology**

**Epidemiology:**

- OKC is a relatively common developmental odontogenic cyst.

- It most commonly occurs in the second and third decades of life.

- OKC shows a predilection for the posterior mandible, often associated with the angle of the mandible or ramus.

- The condition is more frequently seen in males than females.

- There is evidence of familial predisposition, with the potential for multiple affected family members.

**Histology:**

- Histologically, OKC is characterized by a lining of parakeratinized stratified squamous epithelium.

- The epithelial lining is thin and corrugated, and it is often seen as a well-defined, uniform layer.

- The epithelial lining shows a characteristic palisading pattern of basal cells along the surface.

- A prominent feature is the presence of a superficial layer of keratin, giving the cyst its name "keratocyst."

- The fibrous connective tissue wall of the cyst may show inflammation or be associated with satellite cysts.

**Clinical Features:**

- OKC is usually asymptomatic and is often detected incidentally on routine radiographs.

- When symptoms are present, they are typically related to the size of the cyst, which can cause swelling or expansion of the jawbone.

- Large OKCs can cause facial asymmetry and displacement of teeth.

- The cyst has a high recurrence rate, which is a significant clinical feature, making it crucial to carefully manage and follow up with patients.

**Radiology:**

- On radiographs, OKCs appear as well-defined, unilocular or multilocular radiolucencies.

- They have smooth and often corticated borders.

- The cysts can cause displacement and resorption of adjacent teeth.

- Root resorption is common, particularly in cases of larger cysts.

- Recurrence of OKCs can be identified on follow-up radiographs.

**Treatment:**

- The treatment of OKC involves enucleation or marsupialization, depending on the size and location of the cyst.

- Marsupialization involves creating an opening in the cyst wall and allowing the cyst to drain into the oral cavity, promoting decompression and shrinkage of the cyst before complete removal.

- A thorough curettage of the bony walls and surrounding tissue is performed to minimize the chances of recurrence.

- Long-term follow-up is essential to monitor for recurrence, especially during the first few years after treatment.

In conclusion, OKC is a relatively common developmental odontogenic cyst that predominantly affects the posterior mandible. It is characterized by a parakeratinized epithelial lining and has a high recurrence rate. Radiographically, OKCs appear as well-defined radiolucencies. Treatment involves surgical removal, and careful follow-up is necessary to monitor for recurrence. Proper management of OKCs is essential to ensure favorable outcomes for patients.

MCQs on Odontogenic Keratocyst (OKC)

Q1. What is the characteristic histological feature of Odontogenic Keratocyst (OKC)?

Q2. Which age group is most commonly affected by Odontogenic Keratocyst (OKC)?

Q3. What is the predilection site for Odontogenic Keratocyst (OKC)?

Q4. What is a characteristic clinical feature of Odontogenic Keratocyst (OKC)?

Q5. What is the primary histological feature of the epithelial lining of Odontogenic Keratocyst (OKC)?

Q6. What type of radiographic appearance is typically seen in Odontogenic Keratocyst (OKC)?

Q7. What is the common treatment for Odontogenic Keratocyst (OKC)?

Q8. What is the primary concern with Odontogenic Keratocyst (OKC) treatment?

Q9. Which type of epithelium lines the cystic cavity of Odontogenic Keratocyst (OKC)?

Q10. What is the common site for Odontogenic Keratocyst (OKC) recurrence?