Lesions which make the jaws swell are comparatively more common in the developing world than they are elsewhere. Apart from trauma (62.1), the jaws can swell as the result of conditions which include: (1) Infection: an alveolar abscess (5.8), a dental sinus which is sometimes misdiagnosed as an early jaw tumour (26-8), and osteomyelitis (7.14a). (2) Any of the cysts described below. (3) Tumours: Burkitt's lymphoma (32.3), ameloblastoma (see below), carcinoma, salivary tumours (32.23), and giant cell tumours (D, 26-12, A, 32-1). (4) A complex group of fibro-osseous lesions which will not be discussed further here.
In managing tumours, and particularly cysts of the jaw, be aware of the possibility of: (1) A giant cell tumour which is only locally invasive, but may grow very large if it is not treated, as in Figure 32-1. (2) An ameloblastoma (adamantinoma). This arises inside the jaw from the enamel organ of a tooth, and slowly destroys the surrounding bone. It may be solid or cystic, it is locally invasive like a basal cell carcinoma, and does not metastasize. You are unlikely to miss an ameloblastoma if you remember that: (a) The radiolucent lesions it produces are commonly multilocular (the cysts below are mostly unilocular). (b) The solid tissue from around any ''cyst' should be sent for histology, which is the only certain way of making the diagnosis (the cysts below are filled with liquid). If you think that a patient might have an ameloblastoma, refer him for its radical removal.
The following cysts originate from the teeth, and present as smooth, slowly enlarging, painless swellings, usually on the buccal surface of the lower jaw, or on either surface of the upper one. They may be hard, tense, or fluctuant. If the bone over a cyst is thin it may crackle like an eggshell when you press it. Tenderness and pain are signs that a cyst has become infected. These cysts are benign, they can be treated without too much difficulty, and with the exception of an odontogenic keratocyst, they seldom recur.
A dental cyst forms round the apex of a chronically infected, and usually non-vital, tooth, commonly in an older patient. Chronic infection causes the epithelial remnants in the periodontal membrane to grow, and become cystic. Dental cysts are usually quite small, and are commonly symptomless. Occasionally, they grow large enough to expand the alveolus in which they arise. In the maxilla they may encroach on the antra, or the nasal fossae. The fluid they contain is usually clear, but may contain cholesterol crystals. X-rays show a clearly defined, well corticated, unilocular radiolucency, unless the cyst is infected, which causes it to lose its cortex.
A dentigerous cyst usually arises in a young adult from the follicle of a normal unerupted, or erupting, permanent tooth. It expands the outer table of his jaw while the stronger inner one prevents a pathological fracture. The tooth which forms the cyst usually fails to erupt, and you can see that it is missing from its normal place in his mouth. X-rays show a well corticated unilocular radiolucency containing the unerupted tooth. If this tooth is normally placed, opening the cyst may allow it to erupt. Often, it is so misplaced that it cannot erupt, and you will have to enucleate it.
An odontogenic keratocyst (rare) is filled with keratinized epithelial squames. These make the contents creamy, so that it looks like pus, and can only be distinguished from pus microscopically. Don't confuse this cyst with an abscess; there are no signs of infection. X-rays show a well corticated uni- or multi-loculated radiolucency. These cysts are particularly likely to recur after they have been removed (20[nd]60%), so refer him.
Developmental cysts (rare) are not associated with teeth. The commonest one is a nasopalatine cyst, which develops from epithelial remnants in the incisive (nasopalatine) canal, immediately behind the upper front teeth. If it is causing problems it should be enucleated. If this is impractical you may have to marsupialize it, taking care not to injure his incisor teeth and the vessels to them.
Although dental cysts are more common, they are usually small and symptomless, so that dentigerous cysts are more likely to present to you for treatment. There are several ways of treating cysts, and each type of cyst has its preferred method: (1) You can marsupialize a cyst, by removing the mucosa over it, together with the immediately underlying bony wall and lining, washing it out, and then suturing the lining of its floor to the surrounding mucoperiosteum. This relieves tension, stops further expansion, allows drainage, and lets the space the cyst occupied slowly fill up from the bottom. (2) You can pack a cyst open. (3) You can decompress a dentigerous cyst, by opening it, and allowing the tooth in it to erupt. (4) An expert can enucleate a cyst by reflecting a periosteal flap, opening it, removing all its lining, and then replacing the flap. This is more difficult than the preceding methods, and is not described here. (5) An expert can can also excise a piece of jaw with the lesion. This is the treatment of choice for an ameloblastoma, a giant cell tumour, an odontogenic keratocyst, an ossifying fibroma, a carcinoma, and also for fibrosarcoma. Although resected jaw can be replaced with bone or metal, this is not absolutely necessary, because life without a mandible is still worth living, because a patient's tongue is strong enough to crush his food against his palate.
Fig. 26-11 MARSUPIALIZING A CYST. A, a cyst on the gum. B, the area of the mucoperiosteal flap to be reflected. C, removing the bony roof of the cyst. D, trimming the bone from the edges of the cyst. E, preparing to incise the lining of the cyst. F, the cyst opened. G, marsupialization complete. Adapted from Howe and Zamet, ''Minor Oral Surgery', Fig. 194. John Wright with kind permission.
SWELLINGS OF THE JAWS [s8]PARTICULARLY CYSTS EXAMINATION. Stand exactly in front of the patient and inspect his face carefully for asymmetry, especially of his mouth, nostril, and the level of his inner canthi. Feel the mass carefully. Most dental cysts which arise from an apical infection are small ([lt]1 cm), most dentigerous cysts are quite large (3[nd]8 cm). Examine and count his teeth.
If a tooth is missing (and has not fallen out), it may be hidden in a dentigerous cyst.
If one tooth in a line of permanent teeth is much smaller than the others, it might be a persistent milk tooth, with the missing permanent one hidden in a dentigerous cyst.
Aspirate and examine the fluid from the swelling with a wide-bore needle. If you withdraw clear yellow fluid it is a cyst. If you withdraw a substance that looks like pus, it is either true pus from an infection, or a mixture of keratinous squames from an odontogenic keratocyst. Microscopy will tell you which of these it is. Look for dental sinuses (26-8) on his gums or face.
X-RAYS. Take films in two planes. Compare the density of the sinus shadows on either side. A cyst is an area of radiolucency surrounded by a radio-opaque line. If there is a tooth in the cyst it is dentigerous, otherwise it is probably dental.
CAUTION ! (1) Be careful to distinguish a cyst in the maxilla from a normal part of his antrum[md]this can be difficult. (2) The signs that indicate that the lesion is not a simple dental cyst, but a more aggressive lesion are: (a) A multilocular (''honeycomb') radiolucency, indicating an ameloblastoma, an odontogenic keratocyst, or a giant cell tumour. (b) A loss of cortex, indicating an aggressive lesion, particularly a carcinoma. If a benign cyst is infected, it may also lose its cortex.
MANAGEMENT depends on the type of cyst.
If a dental cyst is small and symptomless, leave it.
If it is small but is causing symptoms, remove the tooth and curette the cyst.
If a dental cyst is large, and especially if it is in his upper jaw (unusual), refer him if you can. The danger is that you may create a fistula between his mouth and his nose or his antrum. He may need to have the fistula closed surgically.
If he has a dentigerous cyst which is smaller than about the end of your thumb, you may be able to operate on it, especially if it is in his lower jaw.
MARSUPIALIZING A CYST INDICATIONS. (1) An easier alternative to enucleation for a larger dental cyst. (2) A dentigerous cyst. (3) An elderly patient, in whom there is a risk of pathological fracture.
ANAESTHESIA. Use a combination of local infiltration and pterygopalatine (A 6.4), and mandibular blocks (A 6.3). Thoroughly clean his mouth first.
INCISION. You can approach all cysts from inside his mouth, unless his jaw is to be resected (not described here).
Approach the cyst from the side of the jaw on which the swelling is greatest. If it is equal both sides, approach it from the buccal side. Reflect a large mucoperiosteal flap. Remove bone over the same site. Remove the superficial part of the lining, so as to expose the cavity widely, and render the deeper part of its lining continuous with his oral mucosa. Wash out the cyst, and examine its lining for signs of neoplastic changes. If there is more than a little tissue in it, suspect that it might be an ameloblastoma. Send any material you remove for histology.
If you are marsupializing a dentigerous cyst, be sure to remove all the epithelium, or it may grow again. To do this, remove all the soft tissues on the outside of the bony cyst wall. Remove the tooth at the same time. Leave it open to granulate.
If a dental cyst is related to a permanent tooth, it is likely to be non-vital. It might be saved by root canal treatment, but you will probably have to remove it. If it is related to a deciduous tooth (unusual), remove the tooth.
If the bone is much expanded and the bony wall of the cyst is thin, consider compressing it to reduce its size.
Pack the cavity, and remove the pack at 48 hours or earlier. Continue with thorough mouth washes until it has healed. Ask him to wash out his mouth after meals.
CAUTION ! (1) Be sure to make a wide opening. If it is too small, it will close, and the cyst will recur. Ideally, it may need an acrylic obturator to stop it closing over; failing this pack it.
PACKING OPEN [s7]A CYST INDICATIONS. An infected or ''messy' cyst, with a lining which you cannot completely remove, or a flap which has to be sacrificed.
METHOD. Remove the tooth associated with a dental cyst, unless it can be root-treated. Open the cyst, remove as much of its lining as you can, and then pack it with BIPP impregnated gauze, or plain gauze. Reduce the bulk of this over several weeks, to allow the cavity to granulate slowly from its base.
THE DECOMPRESSION [s7]OF A CYST INDICATIONS. A dentigerous cyst which is small enough for this to be practical (unusual).
METHOD. Remove the surface of the cyst and allow the tooth to erupt.
ENUCLEATING [s7]A CYST If possible, refer the patient. General anaesthesia with tracheal intubation is essential. Approach a cyst in his upper jaw through the labial aspect of his alveolus. Approach a cyst in his lower jaw through an incision 1 cm below the lower border of his mandible, or inside his mouth, through the labial side of his alveolus. Infiltrate the tissues with adrenalin in saline (3.1). Clear the bony covering of the cyst, fracture its eggshell surface, and remove a piece of bone from its most prominent part. Nibble away more bone, and push the cyst off the bony wall of the cavity in which it lies. If it is a dentigerous cyst, its lining will be held round the tooth it contains.
Fig. 26-12 BENIGN TUMOURS OF THE ORAL CAVITY. A, a fibroma. B, a pregnancy epulis. C, a haemangioma of the tongue. D, a giant cell tumour. E, a hard papilloma. Adapted from drawings by Frank Netter, with the kind permission of CIBA-GEIGY Ltd, Basle (Switzerland).