Abstract: Classification for retrognathism malocclusions, assessed and determined by facial concavity, dento-basal compensation, skeletal discrepancy and mandibular morphology, includes dento-alveolar, mandibular positioning and skeletal categories. The skeletal category further consists of 3 subtypes, namely, maxillary originated, mandibular originated and maxillo-mandibular originated. The inspection of cephalometric images reveals that the mandibular contours in dento-alveolar, mandibular positioning and skeleto-maxillary originated categories present with flat and rectangular shapes; and in skeleto-mandibular originated and maxillo-mandibular originated subtypes, massive triangular shapes are distinctive. A longitudinal observation indicates that, spanning the course from the onset to the cessation of pubertal growth spurt, the prognosis of growth patterns remains stable and relatively favorable in dento-alveolar, mandibular positioning and skeleto-maxillary originated categories, but deteriorates and becomes unfavorable in skeleto-mandibular originated and maxillo-mandibular originated subtypes. The skeletal categories with triangle mandible coupled with deep curvature of symphysis hold high likelihood of relapse and are expected to achieve optimal correction by surgical interventions,although the orthopedic therapies are still advisable in the early stage.

Key words: Facial retrognathism, Diagnosis, Classification, Mandibular morphology, Growth pattern predictions