[Occurrence of epithelium in the soft tissues associated with routine surgical removal of 150 mandibular third...

The aim of the study was to classify epithelial structures (ES) and to determine the prevalence of cysts associated with mandibular third molars (M(3)).

Sections of HE-stained soft tissue specimens and panoramic radiographs of 150 consecutive patients undergoing surgical removal of M(3) were evaluated. ES were classified as islands and/or strands of odontogenic epithelium (OE), reduced enamel epithelium (REE), stratified cyst epithelium (SCE), oral mucosa (OM), and pocket epithelium (PE). The diagnostic criteria were defined as a pericoronal translucency >2.5 mm and SCE for dentigerous cysts (DC) and a distal translucency >2.5 mm, SCE, and inflammation for inflammatory paradental cysts (IPC).

Median age was 24.4 years: 23.0 years for 86 (57.3%) female patients and 25.7 years for 64 (42.7%) male patients (p=0.017). ES were found in 95.3%, classified as OE in 53.3%, REE in 34.7%, SCE in 28%, OM in 30.7%, and PE in 10.7%. Both REE and SCE were found in 6%. The total number of cases with REE and/or SCE was 56.7%. Median age of cases with SCE was 28.7 years compared to 20.7 years in cases with REE (p<0.001). Pericoronal translucencies were found in four M(3), of which three were associated with SCE. Distal translucencies were found in 47 M(3), of which 15 were associated with SCE and inflammation. The prevalence was 2% for DC and 10% for IPC.

A differentiated application of histological and radiological criteria enables the prevalence of cystic lesions to be more accurately determined than does the use of one criterion alone.