ETIOPATHOGENESIS AND DIAGNOSTICS OF THE MANDIBULAR PERMANENT FIRST MOLARS RETENTION

The eruption of the first permanent molars is very important as it provides the harmony of the growth of the face and sufficient occlusion support. A delay in the eruption of this tooth can cause morphological, functional and aesthetic disturbances. These include reduced vertical size of the lower face, extruding the antagonist teeth, malloclusion formation, follicular cyst formation, pericoronal inflammation, and roots resorbtion of the adjacent teeth, as well as functional problems of dentoalveolar area, etc. In this regard, the issue of etiology, pathogenesis, early diagnostics and further treatment of lower first permanent molars retention is very relevant for modern orthodontics. In the literary review, morphological and radiological diagnostic criteria of eruption of first permanent lower molars have been presented. Materials and methods of the research. The article reviews and analyzes literature on the etiology, pathogenesis, early diagnostics of retention of the lower first permanent molars. Results The analysis of the literature pointed to a small number of studies regarding the disrupted eruption of first lower permanent molars. In most cases, they are presented as clinical cases. According to the world literature, the prevalence of delayed eruption of the first molar of the mandible was 0.01% to 0.04%. Data from the world literature indicate that the retention of the lower first molar is a polyfactoral disease. According to the etiological factors authors distinguish general and local. Local factors causing delay in teeth eruption include impaired pathway for teeth eruption, abnormality of the tooth form, hyperplasia, displacement of the rudiment because of the cyst and the tumour, loss of space for eruption, gingival fibrosis, idiopathic conditions. Systemic factors include endocrine disorders such as hypothyroidism, hyperthyroidism, hypoparathyroidism, rickets, craniofacial hypertrophy. In the literary review morphological and radiological diagnostic criteria of eruption disturbance of the first permanent lower molars are presented. Thus, the Korean scientists proposed to determine the depth of the retention, the angle of inclination and the space for their eruption on panoramic radiographs. The review presents the classification of retention types for the first permanent molars of the mandible.