Actually there is evidence for enamel in some animals being stronger. Take a look:
markwitton-com.blogspot.com.br… musk deers have exposed tusks, but these have preserved enamel. Walruses are semi aquatic, but their tusks have almost no enamel.
And saying that covered teeth decay way slower is not actually accurate because almost all (if not all) mammals with covered teeth start to get yellowish teeth over time (a clear sign of enamel decay). Crocodilians have a very thin enamel layer and as Mark Witton said, many crocodilians spend a lot of time (some times many weeks) far away from rivers and lakes, altough they still hunt perfectly thanks to tooth replacement (the teeth with decayed enamel are soon replaced by enamel covered ones. Never wondered how can some adult crocodiles have yellowish or even orange teeth while other afult crocodiles have extremely white ones?
I think I have a good explanation here
dovahkiinhu3br.deviantart.com/… that would apply to most animals (musk deers may be an exeption and I have no idea of how they manage to keep their tusks with a great enamel layer). And
, due to all that I said your current smilodon may not be outdated, but broly's "snow leopard smilodon" is also accurate by now, so just chose which one you prefer.