The teeth present in the oral cavity of a newborn are called:
Sometimes, an infant may be born with teeth which are precociously erupted. If these teeth emerge before the first three months of life, they are classified as premature teeth. 
Those that are present at birth, are called natal teeth, those that erupt during the neonatal period, from birth to 30 days are designated neonatal teeth. Al­most 90% of these precociously erupted teeth are primary teeth of which 85% are mandibular incisors and 10% are supernumerary calcified structures fre­quently, referred to as predeciduous teeth. Natal teeth appear more frequently than neonatal teeth.
Reference: Pediatric Dentistry SECOND EDITION, Shobha Tandon; page no 107
Ghost teeth
Infantile teeth
Camel pearls
Natal teeth