layers. Clinical features The dentigerous cyst is often found in areas where unerupted teeth are found. These areas, in decreasing order of frequency, are mandibular third molars, maxillary third molars and maxillary canines. The cyst may grow to a large size, replace the tooth with which they are associated, or hardly cause resorption of adjacent tooth roots. Diagnosis Clinical and radiographic assessments are required to diagnose dentigerous cysts. A cyst is present when the follicular space exceeds 5mm from the crown. However, it is possible that keratocysts and ameloblastomas mimic the radiographical appearance of follicular cysts. Aspiration can be used to differentiate the lesions. Treatment - Marsupialization This procedure is partial removal of associated tooth. The advantage of this procedure is that it maintains the vitality of teeth and is less invasive. The disadvantage is that it required substantial after care and heals very slowly. - Enucleation This procedure is complete removal of the associated tooth. The advantage of enucleation is that the cyst cavity heals eventually and the full cyst tissue is available for histological examination. The disadvantage is that if the cyst involves the apices of adjacent vital teeth, the surgery might deprive the teeth of their blood supply and kill the viral teeth. Odontogenic Tumors Odontogenic tumors may consist of odontogenic epithelium, odontogenic connective tissue or both. Odontogenic tumours consisting predominantly of epithelium arise from odontogenic epithelium. Odontogenic tumours composed of odontogenic connective tissue arise from the ectomesenchymal region of the tooth germ, either from the dental papilla or the dental follicle. Odontogenic tumours of mixed origin contain both ameloblastic epithelium and odontoblastic tissue while in active growth. After complete development, it principally consists of enamel, dentine and cementum. Dental Follicle Stem Cells The presence of stem cells in the dental is an integral part of the DF’s ability to differentiate into the periodontal ligament. Current knowledge about the stem cells present in DFs, is based on the extraction of DFs from immature roots of impacted teeth. In Comparison to the DF of a typically erupted tooth, the DF of an impacted tooth, e.g. third molar, does not surround the tooth and subsequently be divided into two parts. The periapical section: This surrounds the apex of the developing tooth root and mediates tooth eruption. The coronal section: This is attached to developing tooth root and mediates bone growth. Stem cells isolated from these two parts are summarised