Shear's Cysts of the Oral and Maxillofacial Regions. Paul M. Speight

is the most common non‐odontogenic cyst and in some studies has a similar frequency among all jaw cysts to the odontogenic keratocyst (Table 1.1). All the other cyst types are relatively rare.

These data show the relative frequency of each cyst as a proportion of all cyst types, but do not allow a clinician to determine how likely it is that they will encounter a cyst in everyday practice. Jones and Franklin (2006a ) reviewed over 44 000 histologically diagnosed oral and maxillofacial lesions in adults over a 30‐year period. Their data show that all the cyst types described in this book represent about 20% of all biopsies received (n = 8354). Odontogenic cysts were by far the most commonly encountered (n = 6052) and the overall most common cyst type in the maxillofacial regions was the radicular cyst. They found 3793 radicular cysts (including residual cyst), representing 8.6% of all biopsy specimens received. Dentigerous cysts represented 2.5% (n = 1081) of all biopsies, and odontogenic keratocyst was 1.3% (n = 591). By comparing these data to other commonly encountered lesions, a clinician can estimate the likelihood of encountering a cyst. Common diagnoses included 6458 cases of fibrous hyperplasia (14.7%), 2973 cases of lichen planus (6.8%), and 1901 epulides (4.3%; fibrous epulis, pyogenic granuloma, or giant cell epulis). During the same period, there were 3547 periapical granulomas, showing that the frequency of periapical granulomas (8.1%) and radicular cysts (8.6%) is similar. This was also suggested by Koivisto et al. (2012 ), who reviewed 9723 radiolucent lesions associated with the teeth (dentigerous cysts and lesions in the ramus were excluded) and found that 73% were periapical granulomas or cysts. There were 3215 (33.1%) radicular cysts and 3931 (40.4%) periapical granulomas. The next most common lesion was the odontogenic keratocyst (8.8%; n = 857).

Table 1.1 Distribution of 3481 jaw cysts according to diagnosis.

      Source: Data courtesy of Prof. M. Shear, University of Witwatersrand.

	n	% of group	% of all cysts
Odontogenic cysts
Radicular/residual cyst	1825	60.6	52.4
Dentigerous cyst	599	19.9	17.2
Eruption cyst	27	0.9	0.8
Odontogenic keratocyst (including orthokeratinised odontogenic cysts)	355	11.8	10.2
Inflammatory collateral cysts	109	3.6	3.1
Calcifying odontogenic cyst	28	0.9	0.8
Lateral periodontal cyst	24	0.8	0.7
Gingival cyst of adults	21	0.7	0.6
Unclassified	18	0.6	0.5
Glandular odontogenic cyst	6	0.2	0.2
	3012	100.0
Non‐odontogenic cysts
Nasopalatine duct cyst	404	86.1	11.6
Simple bone cyst	35	7.5	1.0
Nasolabial cyst	21	4.5	0.6
Surgical ciliated cyst	5	1.1	0.1
Mucosal cyst of maxillary antrum	4	0.9	0.1
	469	100.0
Total	3481		100.0

Table 1.2 Distribution of 7121 odontogenic cysts in a United Kingdom population.

      Source: Data from Jones et al. (2006 ).

Cysts	n	%
Radicular cyst	3724	52.3
Residual cyst	573	8.0
Dentigerous cyst	1292	18.1
Eruption cyst	15	0.2
Odontogenic keratocyst (including orthokeratinised odontogenic cysts)	828	11.6
Inflammatory collateral cysts	402	5.6
Unclassified odontogenic cysts	210	2.9
Lateral periodontal cyst	28	0.4
Calcifying odontogenic cyst	21	0.3