Can my pregnant wife use ambasol or oragel for a toothache?

Yes. These are topical medications and so not get absorbed at high levels systemically so they are safe. Use only amount recommended.
Go see the dentist. It's a simple question & a simple answer....Go see the dentist. Who knows maybe it's not a toothache.
No. Orajel/abasol can burn the gums due to over use. It is best to brush abd floss regularly. Your wife can also just rinse with small amout of hydrogen peroxide and expirate fully. During pregnacy gums can go through many changed.