How do you know that you lost milk teeth. Did you show a doctor who said it were milk teeth. We need to see whether the permanent teeth supposed to erupt in those positions are present in the bone under the gums, with the help of a CT scan or regular x-ray. Sometimes it might be possible to make such teeth erupt with the help of minor surgery and orthodontic treatment. If such teeth are absent or it would be impossible toake them.erupt normally then definitely you need to restore teeth in its place. Do join " Dr. Runit Nangalia's Painless Dental Practice " on Facebook for finding more answers if you found my opinion helpful.