Odontogenic Cysts

What is Odontogenic Cysts?

Odontogenic cysts, which are often found during regular check-ups, are generally grouped into two categories: inflammatory or developmental. On x-rays, they appear as clear areas with sharp borders that can either be single (unilocular) or multiple (multilocular). However, it’s challenging to differentiate them just based on x-ray images. Also, these cysts can sometimes look similar to aggressive tumors that originate from tooth-forming tissues on x-rays.

The inflammatory types of odontogenic cysts include the following:

• Periapical cyst
• Residual cyst
• Paradental cyst

Meanwhile, the developmental types of odontogenic cysts include:

• Dentigerous cyst
• Eruption cyst
• Lateral periodontal cyst
• Gingival cyst
• Odontogenic keratocyst (OKC)
• Orthokeratinizing odontogenic cyst
• Glandular odontogenic cysts

What Causes Odontogenic Cysts?

A cyst is essentially a small, closed space covered by special cells called epithelial cells. When it comes to odontogenic cysts, which are cysts associated with our teeth, they are lined with specific types of these epithelial cells. These cells include reduced enamel epithelium (REE), the epithelial cell rest of Serres, and Malassez (ERM). The REE is the layer of cells that surrounds the growing cap of a tooth.

The rest of the Serres are leftover pieces from the dental lamina, which starts the process of tooth formation around the sixth week of when we are embryos. The ERM are leftover cells from the breakdown of Hertwig’s epithelial root sheath, which kickstarts the formation of tooth roots. Over time, these remnants get trapped within the gums and bone of the upper (maxillary) and lower (mandibular) jaw.

Periapical cysts, the most common type of odontogenic cysts, are formed due to inflammation at the base (or root) of a dead tooth caused by tooth decay or injury. This inflammation activates and causes an increase in the ERM around the base of the impacted tooth, leading to an increase in pressure, and thus, expansion of the cyst. However, sometimes the ERM is not activated, only creating tissue known as a periapical granuloma. This granuloma lacks an epithelial lining and is sometimes considered as a precursor to a periapical cyst.

Residual cysts are formed when a periapical cyst is not fully removed during tooth extraction and therefore, they are similar to periapical cysts. Looking from a microscopic level, there is no difference between these two types of cysts.

Paradental cysts are odontogenic cysts with an inflammatory cause and might be given different names depending on tooth and location such as a buccal bifurcation cyst or infected buccal cyst. These cysts happen near the crown or root of a partially or fully grown tooth, and are found on various sides of the tooth. Paradental cysts are caused by inflammation of the junctional epithelium, which is within the gum line of a tooth that’s still coming in or already in place.

Dentigerous cysts take shape when fluid collects between the tooth cap and enamel epithelium (the outer layer of the tooth), causing the follicle, the portion that holds the tooth in place, to expand. This often prevents the tooth from coming through. Eruption cysts are similar to dentigerous cysts but happen when the dental follicle doesn’t separate from a growing tooth.

Other cysts like Lateral periodontal cysts, Odontogenic keratocysts (OKC), Orthokeratinizing odontogenic cysts, and Glandular odontogenic cysts arise from either the remnants of the Serres or ERM and are formed during the developmental process.

Risk Factors and Frequency for Odontogenic Cysts

Odontogenic cysts, or cysts related to your teeth, come in multiple types and are more common in certain age groups and regions of the mouth. Here are some key facts:

• Periapical cysts are the most common type, making up about 60% of all these cysts. They are most often found in the upper jaw.
• Residual cysts make up about 5% of all odontogenic cysts.
• Paradental cysts account for 3 to 5% of all these cysts.
• Dentigerous cysts represent about 20.6% of all odontogenic cysts and they make up 20% of all cysts in the lower jaw.
• Eruption cysts usually happen in young children when their baby or adult teeth are coming in.
• Lateral periodontal cysts are less than 3% of all these cysts. About 70% of these happen in the lower jaw’s canine to premolar regions. They occur less commonly in the upper jaw’s canine-lateral area.
• Odontogenic keratocysts represent 4 to 12% of all these cysts and are most frequent in people in their 20s and 30s.
• Orthokeratinizing odontogenic cysts are the rarest kind and usually occur in men in their 40s.
• Glandular odontogenic cysts are also quite rare, accounting for less than 0.2% of all these cysts.

Signs and Symptoms of Odontogenic Cysts

Periapical cysts usually are not visible to the eye, but they are frequently associated with teeth affected by cavities or trauma. These cysts can be found using imaging tests. They are usually located at the root of the tooth and are less than 10mm in diameter.

Residual cysts are similar to periapical cysts and can’t be detected without imaging tests. These cysts usually show up where a tooth was previously removed.

Paradental cysts most commonly occur in young individuals and are usually associated with an emerging or erupted lower back tooth. Signs include swollen gums, pus discharge, and deep gum pockets upon examination.

Dentigerous cysts are connected to the growth or impacted state of a tooth. These cysts most frequently occur during childhood or adolescence and often affect the wisdom teeth and upper canines. They usually don’t cause symptoms unless inflamed.

Eruption cysts can occur in infants or young children when new teeth are emerging. These present as dental swelling with a bluish color.

Lateral periodontal cysts can cause displacement of the roots and are more frequently seen in men during middle age.

Odontogenic keratocysts are mostly symptom-free but can show signs like mouth swelling, pain, inability to open the mouth completely, numbness, and infection. These cysts are difficult to diagnose as they grow within the dental bone. They are most commonly found in people in their twenties.

Orthokeratinizing odontogenic cysts have a lot of similarities with odontogenic keratocyst. However, they have a higher successful treatment rate. Men are most frequently affected, particularly those in their twenties to forties. Usually, these cysts are associated with an impacted tooth.

Glandular odontogenic cysts are more invasive and are primarily detected on radiographs. On examination, signs may include movement of teeth and damage to dental bone. As for the average age of appearance, it’s 46 years, and they affect men slightly more.

Testing for Odontogenic Cysts

A periapical cyst is a kind of inflammation that usually occurs due to deep tooth decay or injury to the tooth. On an X-ray, these cysts seem to be a single, clear area located at the tip of the tooth, and typically have well-defined boundaries.

Residual cysts are somewhat similar to periapical cysts. However, they are not connected to any tooth as the tooth causing the cyst has already been removed. It is crucial to ask about the patient’s dental history to diagnose a residual cyst.

Paradental cysts are typically found attached to a fully grown lower jaw first molar or a partially emerged “wisdom tooth”. They can cause redness, swelling of the gum tissue around the tooth, discharge, and deep gum pockets. Their symptoms may be similar to pericoronitis, a gum disease related to wisdom teeth. On radiographs, they can appear as a single, clear area at the sides of the tooth.

Dentigerous cysts normally occur alongside teeth that have either not emerged yet, or have only partially emerged, this condition is called tooth impaction. They generally don’t cause symptoms unless they become inflamed. X-ray images show dentigerous cysts as well-defined, clear spaces located at the junction of the tooth root and the tooth surface. These cysts might lead to tooth displacement if they are larger than 4 mm.

Eruption cysts are found when a new tooth is coming in, either a baby tooth or an adult tooth. The gum tissue where the new tooth is emerging might seem swollen, blue-colored, and/or see-through. Though these cysts are usually diagnosed by just looking at them, the diagnosis should be confirmed with an X-ray.

The Lateral Periodontal Cyst (LPC) is typically discovered by chance on an X-ray because it usually doesn’t cause pain. These cysts are usually located between two root sections of a tooth. The tooth might seem to have moved or might be loose. Also, the gum tissue between the roots might seem solid and not move when touched, with no signs of infection or redness.

Odontogenic keratocyst are often found in connection with teeth that have not emerged yet. They usually expand front-to-back with little side-to-side growth and therefore go unnoticeable unless they become large and cause symptoms like pain, swelling, limited mouth opening, nerve deficits, infections, and drainage. Patients with multiple odontogenic keratocysts should be checked for Gorlin syndrome, a hereditary condition leading to skin cancer, pits in the palms or soles, multiple odontogenic keratocysts, and calcification in the brain.

Orthokeratinizing odontogenic cysts should not be confused with odontogenic keratocysts. They often occur with impacted teeth, meaning that the teeth have not erupted as expected. On an X-ray, these cysts may look like a well-defined single clear area normally seen in the lower jaw’s back section.

Glandular odontogenic cysts are usually related to teeth that have fully emerged. These cysts may cause the teeth to move or become loose in addition to swelling, bone expansion, or nerve deficiency. On an X-ray, these cysts may appear as single or multiple clear areas with clear boundaries that cross the middle line. They are aggressive and often lead to root displacement and resorption, which is the breakdown and absorption of a tooth’s root.

Treatment Options for Odontogenic Cysts

Periapical cysts, which are a common type of dental cyst, are usually treated with a non-surgical procedure known as a root canal. However, if the tooth continues to cause problems after this treatment, a surgical procedure or tooth extraction may be necessary. In surgical endodontic therapy, the root tip of the tooth is removed, and the cyst is scraped away to encourage bone healing. Alternatively, the tooth can be extracted and the cyst scraped away to prevent another cyst from forming in the same spot. Surgical therapy can result in a 95% chance of bone healing compared to 66% with the non-surgical treatment.

Residual cysts — another type of dental cyst — are typically treated with a procedure called enucleation, which involves removing the entirety of the cyst.

The best treatment for paradental cysts, which are cysts within the tissues surrounding a tooth, will depend on their exact location and the tooth with which they’re associated. For cysts related to the first or second molar, the usual treatment is enucleation. If the cyst is associated with the third molar, however, tooth extraction is usually recommended.

Dentigerous cysts, which are cysts that develop around the crown of an unerupted tooth, are treated by extracting the tooth and then performing curettage (scraping away the cyst) and enucleation. Eruption cysts, which form over the crown of a tooth that’s about to erupt, usually cause no problems and don’t require treatment because they often rupture naturally when the tooth breaks through the gum. However, if an eruption cyst is causing symptoms, it can be “unroofed” or opened to relieve any associated pressure.

Lateral periodontal cysts, which form on the side of the tooth root, are typically managed with curative enucleation. Botryoid odontogenic cysts, clusters of grape-like cysts, often need curettage in addition to enucleation.

Depending on the size and location of an odontogenic keratocyst (OKC), a type of aggressive cyst that can potentially cause considerable bone destruction, different treatments may be necessary. Smaller OKCs can be treated with enucleation and, if necessary, a procedure known as peripheral osteotomy to ensure the surrounding bone is healthy. Larger OKCs may need a procedure called marsupialization, which involves creating a new opening for the cyst to drain, or the more extensive surgical removal called a resection.

Orthokeratinizing odontogenic cysts, which are lined with a particular type of keratinizing epithelium, are typically managed with surgical removal, a procedure that is usually successful in curing this type of cyst. Glandular odontogenic cysts, relatively rare cysts with a glandular appearance, are treated with enucleation and curettage. In more extensive cases, resection may be necessary. For most types of dental cysts, it’s important to have regular follow-up appointments to ensure the treatment was successful and to monitor for any signs of recurrence.

What else can Odontogenic Cysts be?

When diagnosing different types of dental and oral cysts, doctors will need to consider and distinguish between a number of similar conditions. For example:

For a Periapical cyst:

• Periapical granuloma
• Early stages of periapical cementoosseous dysplasia
• Periapical scar

When considering a Residual cyst, potential differential diagnoses include:

• Unicystic ameloblastoma odontogenic keratocyst
• Glandular odontogenic keratocyst
• Lateral periodontal cyst

For a Paradental cyst:

• Periapical cyst
• Dentigerous cyst
• Residual cyst
• Lateral radicular cyst

When diagnosing Dentigerous cyst, doctors will need to consider:

• Hyperplastic dental follicles
• OKC (Odontogenic keratocyst)
• Ameloblastoma

The differential diagnoses for an Eruption cyst include:

• Epstein pearls
• Bohn nodules
• Gingival cyst

Lateral Periodontal Cyst could be:

• OKC (Odontogenic keratocyst)
• Glandular odontogenic cyst
• Gingival cyst

And an Odontogenic keratocyst could potentially be:

• Ameloblastoma
• Dentigerous cyst
• Orthokeratinizing odontogenic cyst

Orthokeratinizing odontogenic cyst differential diagnoses could be:

• Dentigerous cyst
• OKC (Odontogenic keratocyst)
• Ameloblastoma

Lastly, a Glandular odontogenic cyst might be:

• OKC
• Dentigerous cyst
• Botryoid cyst

It’s important for dentists and oral surgeons to carefully rule out these other possibilities when diagnosing cysts in the mouth or jaw.

What to expect with Odontogenic Cysts

The outlook for different types of tooth-related cysts varies:

* Periapical cysts, which form at the root of a tooth, generally have a good outlook after treatment. The prognosis can depend on factors such as which tooth is affected, the size of the cyst, and how much the bone is damaged.

* Residual cysts, which are leftover cysts after a tooth removal, regularly have an excellent outcome and they should not reappear if treated correctly.

* Paradental cysts, cysts that develop on the side of a tooth, also have an excellent outlook with no reported instances of them returning.

* Dentigerous cysts, which form around the crown of an unerupted tooth, have an excellent outlook if properly treated. They can come back if they’re not completely removed during the initial treatment. However, their rate of recurrence tends to be low.

* Eruption cysts, which develop when a new tooth is coming in, typically have a good outlook. They often go away on their own, because the erupting tooth usually breaks the cyst apart.

Lateral periodontal cysts, which form on the sides of the gums, usually have a good prognosis and a very low chance of coming back. Odontogenic keratocysts, cysts that form in the jawbone, range from satisfactory to fair in outlook. These cysts can come back in 20-62% of cases, depending on the treatment used. If treated aggressively, there have been no reported recurrences. However, a different treatment known as enucleation has a reported recurrence as high as 56%. Regardless of the treatment used for these cysts, it’s recommended that patients have regular check-ups.

Orthokeratinizing odontogenic cysts, which have a layer of keratin on the inside, also have a good prognosis with a recurrence rate as low as 2%.

Glandular odontogenic cysts, cysts that form from the salivary glands in the mouth, have an outlook ranging from satisfactory to fair. They have a relatively high chance of coming back, at a rate of 20 to 30%. Because they have a high potential for multiple reoccurrences, long-term regular check-ups are suggested.

Possible Complications When Diagnosed with Odontogenic Cysts

: There are various complications that can arise from different types of teeth-related cysts:

• Periapical cysts usually do not lead to complications after removal. However, sometimes a remaining cyst may form if not all of it was removed during surgery. Also, a scar may appear if the cavity fills with collagenous tissue instead of bone.
• Residual cysts can destroy the bone if not treated which could affect the adjacent teeth. Once removed, these cysts usually do not cause complications and have little to no chances of reappearing.
• Paradental cysts can result in a deep gum disease due to a deep periodontal pocket which might damage gum tissue. Typically, they do not bring upon any other complications after removal and do not reoccur.
• Dentigerous cysts can cause bone damage due to growth. They usually do not cause any complications once removed and rarely reappear.
• Eruption cysts usually resolve on their own and do not cause complications.
• Lateral periodontal cysts also do not bring upon any complications after removal and do not reoccur.
• Odontogenic keratocysts have a high chance of reappearing so continuous monitoring is necessary. If a reoccurrence happens, additional surgery may be needed.
• Orthokeratinizing odontogenic cysts have a low chance of reappearing and do not cause complications after removal.
• Glandular odontogenic cysts have a high chance (20 to 30%) of reappearing. Therefore, regular and long-term check-ups are necessary. Multiple reappearances could happen and if it does, additional surgery may be required.

Preventing Odontogenic Cysts

Periapical cysts are a kind of swelling that is caused by inflammation in your mouth. To manage them, it’s vital to keep your mouth clean and visit your dentist regularly for check-ups. Your healthcare provider will review any unusual areas in your mouth that might be seen during your check-up, and talk with you about the best options for managing any odd growths. It is key that patients get a clear understanding of their condition, especially if it seems unresponsive to the initial treatment.

Residual cysts are another type of inflammation-related growth that can develop if a prior surgery didn’t remove everything. Regular visits to your dentist can help catch these early. Your healthcare provider will explain to you any unusual findings and may advise a biopsy (taking a small sample of the area) to check for other possible problems.

Paradental cysts, like periapical cysts, are due to inflammation. Keeping good oral hygiene and having regular dental check-ups, including a special dental x-ray, can help manage them.

Dentigerous cysts start developing when you’re still in the womb. If you have such a cyst, your healthcare provider will explain it to you and present their thoughts about what else it might be. They might suggest a more conservative approach initially, such as removing any impacted teeth (teeth that have not come in properly), with a biopsy to check for any other problems. Usually, these cysts are completely gone after surgery.

Eruption cysts also start forming while still in the womb, are usually harmless and resolve on their own. Your healthcare provider will assure you that these cysts generally resolve once the tooth underneath comes in.

Lateral periodontal cysts form while you’re still developing in the womb. If you have this type of cyst, your healthcare provider will let you know what it is and recommend removing it. After the cyst is removed, it tends to stay away for good.

Odontogenic keratocysts, similar to above, form while you’re still developing in the womb. You will be informed if you have this lesion, and surgical removal will be planned. However, these cysts have a high chance of coming back, so it’s crucial to have frequent and long-term check-ups.

Orthokeratinizing odontogenic cysts form early in life within the womb. If you have this type of cyst, your healthcare provider will explain it to you and suggest removing it. Once these cysts are removed, they typically don’t return.

Glandular odontogenic cysts also start in the womb. Your healthcare provider will inform you if you have this kind of cyst, talking to you about its usual course and what might happen. Different methods of managing this cyst will be discussed, with time for you to ask questions. As these cysts can often come back, close monitoring through frequent check-ups is necessary.