Careful investigation of the blood is often the first step in the assessment of hematologic function and diagnosis of related diseases; many hematologic disorders are also identified by specific blood tests. Blood smears and hematologic parameters examination yields important diagnostic information about cellular morphology, quantification of the blood cellular components, and evaluation of the pathophysiology that allows the formation of broad differential diagnostic impressions, directing additional testing. Apart from investigations, model analysis and observation plays an important role in Pediatric Dentistry.