My lo is turning 9 months this coming 17th of the month, Ask ko bakit wala parin siyang natubong ngipin? Is this normal? And how do u handle teething?

My baby had her first four teeth (2 taas 2 baba) when she was 15 months old. Sabay sabay po yun lumabas, days lang Yung pagitan. at hanggang ngayon, 17 months na sya, di pa nadadagdagan yung apat na yun hehe