A. Signs And Symptoms
1. Bony Expansion
Small cysts usually presents no
expansion. Nowever, as the cyst increase in size expansion of the alveolar plate occurs. In cases of odontogenic cysts usually the labial or the buccal plate of the lower jaw is expanded. Expansion of the lingual plate may be an indicative for another lesion.
The sequence of events of cyst expansion shown in figure 1 is usually observed in cases of inflammatory and dentigerous cysts. Odontogenic keratocyst, on the other hand, tends to cause little expansion that may be overlooked. Soliatory bone
cyst usually produce expansion late in its course.
Fluctuatioin occurs when the bone overlaying the cyst become resorped due to increased cystic pressure and the cyst lining comes in contact with
the oral mucosa. The sensation of fluctuation can be convyed via the cystic fluid. Fluctuation can be demonestrated by applying a firm interrupted pressure with the fingre of one hand over the lesion and detecting the transmitted wave with the fingure of the
other hand placed onthe opposite side oft he lesion.
Fig. 1. Sequence of cyst expansion.
Although periodontal and dentegerous cysts may occur any where in the jaws yet ther is some site
predlecation for certain types of cysts. (Table 1)
4. Teeth related to the cyst
Benign cysts rarely cause loosening to the adjacent teeth until the cyst attain very large size. If the cyst develope between two teeth it usually cause the
roots to diverge and the crowns to converge. Large cysts in the maxill frequentelly displace the roots of the adjacent teeth buccaly so that the crowns of the teeth are inclined palatally. Table 2 shows a list for some creteria of adjoining teeth.
5. Paraesthesia of the inferior dental nerve
Although large mandibular cysts usually involve the neurvascular bundle, and may even deflect it to an abnormal position, paraesthesia of the
nerve distribuation is very rare. Nerve paraesthesia usually occurs when the cyst becomes infected and the accumulation of the inflammatory exudate results in sudden increase in the intercystic pressure. This result in neuroperxia of the nerve and immediate
onset of lower lip paraesthesia.
1. Pain and swelling
Small cysts are usually symptomless, the frist symptom is usually pain and swelling when the cyst becomes infected or attain
2. Bad taste
If an infeted cyst discharge pus into the mouth the patient may complain of a nasty taste. On the other hand, if the cyst attain large size and presents a sinus discharging cystic fluid
the patient complain of a salty taste.
3. Irrigularitis in dentition
As the syst may cause displacement of the adjacent teeth the patient may complain of irrigularitis in dentition that was not present. Thew patient
may also complain of discloration of a nonvital tooth associated with a periapical cyst.
4. Pathological fracture
When the cyst attain a large size it may cause pathological fracture in the weakened mandible.
It is surprisingly how few symptom a pathological fracture may cause. Sometimes only a click followed by mild discomfort and progressive but slight disturbances in occlusion are all the symptoms of a pathological fracture.
5. Edentulous patients.
In edentulous patients cysts may cause discomfort of a previously well fitting denture, which may be dislodged by an expanding cyst. At the area where the denture flange cut into the growing lesion a denture granuloma may develop.
Aspiration of a suspected cyst is a very useful diagnostic aid, especially when doubt still exist about the nature of the lesion after clinical and radiographic
A wide pore needlw should be used. It is inserted in the suspected cystic lesion under local anaesthesia and the cavityu is aspirated. A provisional diagnosis of benign cyst will be confirmed if the aspirated fluid is a
ligth straw-colored fluid containing cholestrol crystals. The presence of the cholestrol crystals can be easily demonestrated by running some of the aspirated fluid onto a dry swab glass. The smear is then viewed under strong light
micrscope where the cholestrole crystals can be identified by their distinctive shape "Rectangular with one corner missing". Table 3 Shows defferntial diagnosis of aspiration biopsy.
Radiography is an essential diagnostic aid in diagnosis of cystic lesions. Intraoral periapical films usually demenstrate small cysts. In case of large cysts only part of the cystic lesion will be seen
in the film (Figs 1-2 and 1-3). This is due to the small size of the film. Intraoral occlusal films, on the other hand, are very useful in cases of maxillary lesions to show the amount of palatal bone destruction (Fig. 1-4). In the mandible occlusal films
the degree of expansion of the outer and inner cortical plates (Fig. 1-5).
Extraoral radiographs (Table 1-4) generally demonestrate the extent of the cystic lesion, the displacement of the adjacent teeth and the encroachment of the lesion
uppon vital important structures as the maxillary sinus, the inferior border of the mandible or the orbiatal cavity. (Fig. 1-6)
Fig, 2. Aspiration biopsy.
The use of radio-opaque medium
Radio-opaque materials, as lipedol, may be
injected into the cystic lesion to aid in the explortion of the extent of the cystic cavity (Fig. 1-7). Indications for the use of radio-opaque medium and the technique used are both shown in table 1-5.
Fig. 3. The use of radio-opaque media to demonstrate the extent and relation of the cyst. The extent of the cyst can be determined. A cyst within the maxillary sinus can be clearly
1. Shape of the lesion
Small cysts in cancellous bone are round, as they expand their circular shape tends to be lost. This is attributed
to the defference in the degree of resistance of the bone surrounding the lesion. When a mandibular cyst comes in contact with the cortical plates it tends to expand along the longitudinal axis on the expense of the less solid cancellous bone.
Perforation of the cortical plates
When either or both mandibular corticxal plates are perforated the resultant hole is evedinced by a well demarcated dark shadow. When the images of perforations of both cortical plates partly
overlap, a complex image of false multilocularity is produced.
3. Relation to the mandibular canal
The presence of a large cyst in the mandible may cause downward displacement of the mandibular canal with discontinuing
of one or both of the cortical lines which outline the canal. The inferior dental bundle may come to lie within the cystic capsule.
4. Maxillary cysts
Maxillary cysts are usually discovered when they attain alarge
size, yet there may be no clinical expansion.
5. The presence of unerupted tooth
The presence of an unerupted tooth in relation to a radioleucent area is not necessary diafgnostic for dentigerous cyst. The tooth
may be associated with a neoplasm or another type of cyst the enlagrgement of which enclose the tooth at an early stage.
Multilocularity is usually false in true bvenign cystic lesions being
a projection effect of the bony elecations or ridges in the bony walls of the cyst which result from uneven bone resorption. Also false multilocularity may result from partial superimposition of resorption defects in the buccal and the lingual cortical plates.
7. Palatal cysts
Palatal cysts usually do not cross the midline line. This may be attributed to the restraining effect of the median suture of the hard palate which closes late about the 5th decade of life.
Radiographic defferntiation between maxillary sinus and maxillary cyst
- The antrum has certain anatomical structures while the cyst is structureless.
- The maxillary sinus are symmetrical and onther cavity will be found on the other
- Teeth projecting into the cavity retain an intact lamina propria when related to the maxillary sinus.
9. Radiographic defferntiation of mucous cyst
- Relatively radioopaque shadow in relation to the
dark shadow of the air filled cavity of the sinus.
- The lesion is devoid of white border on its free upper surface.
- Usually no displacement or resorption of the antral floor which is possible with odontogenic cysts.
- The maxilary teeth
in relation to the cyst has an intact lamina propria.
- The cyst may arise from any wall of the sinus and not confined to the floor.