Читать книгу Shear's Cysts of the Oral and Maxillofacial Regions - Paul M. Speight - Страница 62

In 1970 Main proposed a classification of jaw cysts based on a review and analysis of 274 odontogenic cysts. He found eight cysts (2.9%) that arose ‘alongside a vital tooth involved in pericoronitis’, which he called an inflammatory collateral cyst, in recognition of their association with chronic inflammation and a location on the lateral aspect of a tooth. This term also distinguishes it from a radicular cyst associated with a lateral accessory root canal of a non‐vital tooth, and from a developmental lateral periodontal cyst. Seven of his eight cases arose on mandibular third molars, and one on an impacted upper canine (Main 1970 ). Main's 1970 paper is often cited as the first report of this cyst, but Philipsen et al. (2004 ) found that Hofrath in 1930 had reported several jaw cysts on mandibular third molars affected by pericoronitis. Hofrath called these cysts ‘marginal wisdom tooth cyst’, but all the features were consistent with the inflammatory collateral cyst described by Main (1970 ) and the paradental cyst as currently defined.

The first detailed account of inflammatory collateral cysts was by Craig (1976 ), who described a cyst of inflammatory origin that occurred on the lateral aspect of the roots of partially erupted mandibular third molars where there was an associated history of pericoronitis. He recognised that these cysts were the same clinicopathological entity as the inflammatory collateral cyst described by Main (1970 ), but he was the first to suggest the term paradental cyst. He felt this was more appropriate for this lesion because it emphasised the odontogenic associations of the cyst and its location adjacent to a tooth.

Craig's series consisted of 49 cysts in 48 patients, which represented about 5% of odontogenic cysts seen in his department over a 21‐year period. In all cases the involved tooth was partially erupted and was associated with a history of pericoronitis. In terms of location, 26 cysts were on the buccal aspect of the roots, 19 were distal, and 4 were mesial, but Craig was of the opinion that there was some buccal involvement even in those cysts designated clinically as of mesial or distal location. Macroscopically, the cysts were firmly attached to the bifurcation area on the buccal aspects of the roots, and extended up to the cementoenamel junction. Craig's description of the paradental cyst associated with third molar teeth has become the defining feature of this lesion.

Craig's paper on the paradental cyst was, for a number of years, the only detailed account of the entity. Subsequently, however, Ackermann et al. (1987 ) described 50 cases, all of which arose on impacted third molars and had similar features to those described by Craig. This was soon followed by a report of 6 cases by Fowler and Brannon (1989 ) and 15 cases by Vedtofte and Praetorius (1989 ), and then by numerous case reports and a number of case series or reviews (de Sousa et al. 2001 ; Colgan et al. 2002 ; Philipsen et al. 2004 ; Mohammed et al. 2019 ).

In 1983, Stoneman and Worth described 17 cases of a lesion that was similar to the inflammatory collateral cyst (Main 1970 ) and the paradental cyst (Craig 1976 ), but that arose primarily on the buccal aspect of mandibular first and second molars in children. They named this entity the mandibular infected buccal cyst to emphasise its origin in inflamed periodontal tissues of partially or fully erupted molars. Stoneman and Worth (1983 ) did not refer to the reports of Main or Craig and although they emphasised their lesion as being on first and second molars, three of their cases involved the third molar region. It seems therefore that the mandibular infected buccal cyst and paradental cyst share similar clinical and histological features and should be regarded as variants of the same lesion. This is suggested by more recent papers that have reappraised these cysts and consider them to be the same entity (Packota et al. 1990 ; Wolf and Hietanen 1990 ; Thurnwald et al. 1994 ; Pompura et al. 1997 ; Thompson et al. 1997 ; Chrcanovic et al. 2011 ; Ramos et al. 2012 ). Pompura et al. (1997 ) suggested the term mandibular buccal bifurcation cyst for these lesions, since it described the location of the cyst and reflected the fact that not all lesions are overtly infected.

None of these cysts appeared in the first (1972) edition of the WHO classification of odontogenic tumours and cysts, but they were included in the second edition (Kramer et al. 1992 ). The 1992 WHO classification used the term paradental cyst, but included inflammatory collateral cyst and mandibular infected buccal cyst as synonyms. The classification did however make a distinction between cysts arising in association with third molars and a distinctive variant arising on the buccal aspect of first molars in children.

In a review of the world literature, Philipsen et al. (2004 ) concurred with this view, but found that the literature included at least 16 names for these cysts, including marginal wisdom tooth cyst (Hofrath 1930 ), inflammatory collateral cyst (Main 1970 ), paradental cyst (Craig 1976 ), mandibular infected buccal cyst (Stoneman and Worth 1983 ), and mandibular buccal bifurcation cyst (Pompura et al. 1997 ). Slater (2003 ) had suggested eruption pocket cyst, which nicely describes the association with an erupting tooth as well the morphological feature of a pocket cyst. Nevertheless, this name was never used again in the literature. Philipsen et al. (2004 ) preferred to use the term inflammatory paradental cyst to encompass all the collateral cysts of inflammatory origin. They pointed out, however, that differences in clinical presentation and appearance justify separating the cyst into clinicopathological variants. In the literature up to 2004 they identified reports of 342 patients with 377 cysts. The most common lesions, representing 61.4% of cysts, arose in adults and were associated with a mandibular third molar. The second group, comprising 35.9% of cysts, were related to the first and second molars and arose in younger individuals with a characteristic clinical presentation. A further 10 cysts (2.7%) were described as occurring in the gobulomaxillary region between the second incisor and canine. Eight of these ten cases were reported by Vedtofte and Holmstrup (1989 ). There are also reports of four cysts arising in association with mandibular premolars (Morimoto et al. 2004 ) and one case arising on a maxillary second molar (Vedtofte and Praetorius 1989 ).

It is apparent from this discussion that all these terms refer to a similar lesion and have been used synonymously to describe an inflammatory collateral cyst that arises towards the buccal aspect of a partially, or recently, erupted tooth. It is also clear that the vast majority of cysts (about 97%) fall into two main groups – those associated with third molars and those associated with first or second molars. In the previous edition of this book we suggested that these two variants should be called paradental cyst, using the criteria of Craig (1976 ), for lesions associated with third molars and juvenile paradental cyst for lesions in younger individuals associated with mandibular first or second molars. Subsequently, however, the 2017 WHO classification (Speight and Soluk Tekkeşin 2017 ) adopted the term inflammatory collateral cysts for all cysts found towards the buccal aspect of the roots of partially or recently erupted teeth, and described the two main types as paradental cyst and mandibular buccal bifurcation cyst. This terminology has been retained in the latest edition of the WHO classification (WHO 2022a ; Speight and Soluk Tekkeşin 2022b ).

Although the paradental cyst is usually defined as arising on mandibular third molars, identical lesions have occasionally been described on second permanent molars when the third molar is absent and the second molar is the last standing tooth (Vedtofte and Praetorius 1989 ; Maruyama et al. 2015 ). Thus the definition of the paradental cyst might more appropriately refer to the ‘last standing mandibular molar tooth’. The vast majority, however, are located on third molars. The key features of the two main variants are summarised in Box 4.1 and later Tables 4.2 and 4.3.