Dr. Ahmed M. Adawy Professor Emeritus, Dep. Oral & Maxillofacial Surg. Former Dean, Faculty of Dental Medicine Al-Azhar University. By definition, a cyst is a “pouch” or sac without an opening, provided with a distinct membrane, and containing fluid or semifluid material, abnormally developed in one of the natural cavities or in the substance of an organ. Cysts of the oral region may be epithelial or non-epithelial, odontogenic or non-odontogenic, developmental, or inflammatory in origin. The distribution of jaw cysts according to diagnosis in a general population is given. The treatment of choice is dependent on the size and localization of the lesion, the bone integrity of the cystic wall, its proximity to vital structures and patient age.Treatment modalities are discussed.

2. Dr. Ahmed M. Adawy
Professor Emeritus, Dep. Oral & Maxillofacial Surg.
Former Dean, Faculty of Dental Medicine
Al-Azhar University

3. The word cyst is derived from the Greek word Kystis
meaning sac or bladder (1). By definition, a cyst is a
“pouch” or sac without an opening, provided with a
distinct membrane, and containing fluid or semifluid
material, abnormally developed in one of the natural
cavities or in the substance of an organ (2). Cysts of the
oral region that are lined by epithelium are known as true
cysts, while those not lined by epithelium are generally
referred to as pseudo-cysts

4. Cysts of the oral region may be epithelial or non-
epithelial, odontogenic or non-odontogenic,
developmental, or inflammatory in origin. The
distribution of jaw cysts according to diagnosis in a
general population is: radicular cysts 56%, dentigerous
cysts 17%, nasopalatine duct cysts 13%, odontogenic
keratocyst 11%, globulomaxillary cysts 2.3%, traumatic
bone cysts 1.0%, and eruption cysts 0.7% (3,4)

5. A revised histopathological classification of odontogenic
tumors by the World Health Organization (WHO) has been
published in 2005 (5), in which odontogenic keratocyst and
calcifying odontogenic cyst were re-classified as tumors.
Likewise, aneurysmal bone cyst and the solitary bone cyst
have been described as ‘cavities’ rather than cysts (6). Cysts
historically named globulomaxillary, median palatine and
median mandibular cysts have been shown by numbers of
studies as odontogenic or developmental cysts. This
terminology is no longer used in diagnostic oral pathology
departments in most parts of the world (4)

6. Cysts, especially epithelial cysts, are more commonly seen
in jaw bones than other parts of the body. The higher
incidence of cysts within the jaw bones is probably due to
the abundant amount of epithelial remnants that can be left
in the bones of the jaws during development. This
"resting" epithelium is usually dormant or undergoes
atrophy, but when stimulated, may form a cyst. Cysts that
arise from tissues that would normally develop into teeth
are referred to as odontogenic cysts. Other cysts of the
jaws are termed non-odontogenic cysts. At least 90% of all
jaw cysts are of odontogenic origin

7. Odontogenic cysts are group of lesions that originate from
the tissues derived from tooth forming apparatus (7). They
are slow growing and do not pose a significant
management challenge, however, since they grow within
the bones, they may cause bone or tooth resorption, bone
expansion, fracture, or tooth displacement (8). They are
divided into inflammatory and developmental

8. Radicular cysts are the most common cystic lesions which
affect the jaw. They arise from epithelial remnants which
are stimulated to proliferate, by an inflammatory process
which originates from pulpal necrosis of a non-vital tooth.
They are most commonly found at the apices of the
involved teeth. However, they may also be found on the
lateral aspects of the roots in relation to lateral accessory
root canals. They are symptomless and are diagnosed
during routine radiologic investigations. Cortical
expansion and root resorption of the affected tooth and
displacement of the adjacent teeth are common features of
radicular cysts

9. According to the literature, the most frequently affected
site is the anterior maxilla (9). The higher prevalence of
male sex in some studies may be explained by the fact that
men usually have poorer oral hygiene habits and are more
susceptible to trauma than women (8). Their prevalence is
highest among patients in their third and fourth decades of
life (9). Radiographically, the lesion is presented as well a
defined round or oval radiolucent area surrounded by
radiopaque margin. However, if the cyst is infected, it will
have a hazy margin

10. Radicular cysts

11. Residual cysts are retained radicular cysts from teeth that
have been extracted. The diagnosis of this pathology was
more prevalent in patients over 50 years old (10). The
finding that patients with residual cysts are older than
patients with radicular cysts may be explained by the fact
that cystic lesions are located inside the maxilla, cause no
clinical symptoms after tooth extraction, and are only
detected months or years later because of secondary
infection or as an incidental radiographic finding

12. Residual cysts

13. Dentigerous cysts have been defined as those surrounding
the crown of a tooth that has not migrated into the oral
cavity, but still lies buried in the jaw bone (11). It has been
reported that dentigerous cysts are the second most
prevalent odontogenic cysts . The posterior region of the
mandible is the most frequently affected site, followed by
the anterior maxilla (10). Such prevalence may be
explained by the large number of impacted mandibular
third morals and maxillary canines. Most dentigerous
cysts are found in patients in the second decade of life

14. Dentigerous cysts have the potential to resorb and expand
into the surrounding tissue and displace bone and tooth
roots causing malocclusion or facial asymmetry. Inferior
alveolar nerve paresthesia caused by a dentigerous cyst
have also been reported (12). However, in most of the
cases this cyst is asymptomatic and diagnosed on routine
dental radiographs usually appearing as a well defined
radiolucency associated with the crown of an unerupted
tooth

15. Dentigerous cyst

16. According to the WHO classification, nasopalatine duct
cyst is defined as a nonodontogenic, developmental,
epithelial cyst of maxilla (13). Most of these cysts develop
in the midline of anterior maxilla near the incisive
foramen. It constitutes about 1.7–11.9% of all jaw cysts.
Most cases occur in the fourth to sixth decade and men are
affected three times more commonly than women. The
lesion is believed to arise from epithelial remnants of the
nasopalatine duct. These epithelial remnants either by
spontaneous proliferation (idiopathic) or proliferation
following trauma, or bacterial infections may become the
source in giving rise to nasopalatine duct cyst

17. Most of these cysts are asymptomatic or cause minor
symptoms such as swelling in relation to anterior palate
near incisive papilla. Sometime cyst may be so destructive
may perforate the labial and palatal bony palate. Tooth
displacement is common finding (14). Differential
diagnosis includes radicular cyst, and a wide incisive
canal. A radicular cyst is usually associated with non-vital
teeth, while, the nasopalatine cyst is usually associated
with vital teeth. Radiographically, the lesions are
well- circumscribed round, ovoid, or heart shaped
radiolucencies located in between the roots of the
maxillary central incisors

18. Nasopalatine duct cyst

19. Aspiration with a 16 or 18 gauge needle is first done in all
cases because some lesions of the same clinical and
radiographic findings may well have been tumors and not
cysts. Next, an incisional biopsy prior to definitive
treatment is carried out to differentiate the “cyst”
form other lesions having similar presentations ,
such as a keratocystic odontogenic tumor or unicystic
ameloblastoma, but are more aggressive and necessitate
more extensive treatment and the sacrificing of vital
structures, bone, and teeth (15)

20. Aspiration

21. The treatment objective is restoring the morphology and
function of the affected area. There are two basic surgical
procedures, namely enucleation and marsupialization
(decompression). The treatment of choice is dependent on
the size and localization of the lesion, the bone integrity of
the cystic wall, its proximity to vital structures and patient
age (16). Enucleation means shelling out the entire cystic
lesion without rupture. Marsupialization refers to creating
a surgical window in the wall of the cyst, excavating the
contents of the cyst and maintaining continuity between
the cyst wall and the oral cavity. Only a portion of the cyst
is removed with the remaining left in situ

22. Enucleation is defined as a complete removal of the cystic
lining with healing by primary intention. Enucleation with
primary closure is the treatment of choice (17). It is a one
stage surgical treatment followed by periodic radiographic
examinations at regular intervals to observe the progress of
bone regeneration of the defect. It also allows pathologic
examination of the entire specimen. Enucleation can be
done only when the jaw bone adjacent to the cyst is intact.
This procedure is usually indicated for a small cyst, which
can be done when the vital structures are not involved. If
CT demonstrates erosions in the buccal or lingual cortices,
marsupialization should be the treatment of choice

23. Enucleation with bone grafting is performed with large
cystic lesions. Allogenic or xenogenic demineralized
freeze-dried bone have been used for grafting with
satisfactory results. Autogenous cancellous bone is
considered the best grafting material and has been used
with clinical success for treatment of cystic lesions for
many years. However, donor site morbidity, is a factor to
be considered. Its use for grafting of cystic lesions should
be restricted if bone substitutes are available. Some
grafting materials, however, are not always completely
replaced by bone, and are encapsulated by connective
tissue with maintaining of chronic inflammation, enhance
bone resorption or partially rejected (18)

24. Enucleation

25. Dentigerous cyst
Six months
post-enucleation

26. Marsupialization (Partsch’s operation), is the conversion
of a cyst into a pouch (19). It is a relatively simple
procedure, consists of surgically producing a window in
the cystic wall to relieve intra-cystic tension. The
technique promotes shrinkage of the cyst as well as bone
fill. It is indicated when cyst is in close proximity to vital
structures and where there is significant risk of injury with
enucleation. The marsupialization concerns not only the
radicular cysts, also follicular cysts can be treated by this
technique in order to conserve and guide the eruption of
permanent teeth. Three to six months later, enucleation is
performed

27. The technique requires considerable aftercare and patient
cooperation in keeping the cavity clean whilst it resolves
and heals by relieving the internal pressure. The notable
disadvantages of the marsupialization are: (a) it is a two-
stage surgical procedure, (b) pathological tissue is left
behind and a more sinister pathological process (i.e.
squamous cell carcinoma) may be overlooked (20), and (c)
in a large cystic cavity it takes a long period of time for the
bone to regenerate

28. Marsupialization

29. Marsupialization

30. Decompression can be performed by making a small
opening in the cyst and keeping it open with a drain (21).
Decompression and secondary enucleation of cystic
lesions constitute an alternative treatment for large cystic
lesions of the jaws. This technique is especially
appropriate for young patients, as there will be less
damage to important structures like unerupted teeth.
Decreased lesion size after decompression makes
complete enucleation a safer and more predictable
procedure

31. Numerous devices and adaptation methods were suggested
and successfully used for maintaining the opening during
decompression. The common materials used for making
decompression devices are acrylic stents, nasopharyngeal
airways, polyethylene tubes, nasal cannula, Luer syringes,
and polyethylene intravenous tubes (22). These devices
are secured by sutures or wiring fixation

32. Decompression devices

34. 1. Nair PN. New perspectives on radicular cysts: do they heal? Int Endod J;
31: 155, 1998.
2. Archer WH. Oral and Maxillofacial Surgery, 5th ed. W.B. Saunders Com.
pp 518, 1975.
3. Killy HC, Kay LW. An analysis of 471 benign cystic lesions of the jaws.
Int Surg ;46: 540, 1966.
4. Shear M, Speight PM. Cysts of the oral and maxillofacial regions; 4th
edition. Oxford: Blackwell Munksgaard; 2007.
5. Barnes L, Eveson JW, Reichart P, et al. World Health Organization
Classification of Tumors. Pathology and Genetics of Head and Neck
Tumors. Lyon: IARC Press; 2005.
6, Reichart P, Philipsen H. Odontogenic tumors and allied lesions. New
Malden: Quintessence Publishing: 2004.
7. Jordan RCK, Speight PM. Current concepts of odontogenic tumours.
Diagnostic Histopathology; 15: 303, 2009.
8. Meningaud JP, Oprean N, Pitak-Arnnop P, et al. Odontogenic cysts: a
clinical study of 695 cases. J Oral Sci; 48: 59,2006.

35. 9. Jones AV, Craig GT, Franklin CD. Range and demographics of
odontogenic cysts diagnosed in a UK population over a 30-year period. J
Oral Pathol Med; 35: 500, 2006.
10. Ochsenius G, Escobar E, Godoy L, et al. Odontogenic cysts: analysis of
2,944 cases in Chile. Med Oral Patol Oral Cir Bucal;12: E85, 2007.
11. Slootweg PJ. Lesions of the jaws. Histopathology;54:401, 2009.
12. Summer M, Bas B, Yildiz L. Inferior alveolar nerve paresthesia
caused by dentigerous cyst associated with three teeth. Med Oral Patol Oral
Cir Bucal; 12:E388–E390, 2007.
13. Francoli JE, Marques NA, Aytes LB, et al. Nasopalatine duct cyst:
Report of 22 cases and review of literature. Med. Oral Patol. Oral Cir.
Bucal; 2008, 13: 438, 2008.
14. Basso ECB, Neto ER, Dib LL, et al. An unusual case of nasopalatine
cyst in Brazilian population. Health Sci Inst; 30: 292, 2012.
15. Motamedi M H K: Periapical ameloblastoma: a case report. Br Dent J;
193: 443, 2002.

36. 16. Bodner L. Cystic lesions of the jaws in children. Int J Pediatr
Otorhinolaryngol; 62: 25, 2002.
17. van Doorm ME. Enucleation and primary closure of jaw cysts. Int J Oral
Surg;1:17, 1972.
18. Lalabonova K, Daskalo H. Jaw cysts and guided bone regeneration
(a late complication after enucleation). J of IMAB; 4: 401, 2013.
19. Sakkas N, Shoeen R. Obturator after marsupialization of a
recurrence of a radicular cyst of the mandible. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod; 103 : 16, 2007.
20. Bodner L, Manor E, Shear M, et al. Primary in-traosseous squamous
cell carcinoma arising in an odontogenic cyst- A clinicopathologic
analysis of 116 reported cases. J Oral Pathol Med; 40: 733, 2011.
21. Pogrel MA. Treatment of keratocysts: The case for decompression
and marsupialization. J Oral Maxillofac Surg; 23: 1667, 2005.
22. Costa FW, Carvalho FS, Chaves FN, et al. A suitable device for cystic
lesions close to the tooth-bearing areas of the jaws. J Oral Maxillofac
Surg; 72: 96, 2014.