Deciduous teeth first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars. The primary teeth are made up of central incisors, lateral incisors, canines, first molars, and secondary molars; there is one in each quadrant, making a total of four of each tooth. All of these are gradually replaced with a permanent counterpart except for the primary first and second molars; they are replaced by premolars. The replacement of primary teeth begins around age six, when the permanent teeth start to appear in the mouth, resulting in mixed dentition. The erupting permanent teeth cause
Dragon's teeth (fortification) those formed after the breakup of Yugoslavia, have movable teeth, positioned at roadsides at strategic locations, which are to be lifted and placed on the roads. Some stages of Rallye Deutschland, the German round of the WRC rally championship, are run on roads belonging to the military training ground at Baumholder. The roads are lined with dragon's teeth, known as 'Hinkelsteine'. They usually serve as obstacles to prevent tanks from leaving the roads, and cause devastation to any rally car which veers off track. Notes Dragon's teeth (fortification) Dragon's teeth () are square-pyramidal fortifications of reinforced concrete first used during