Are lumineers good for less than half broken front tooth?

Probably not: Lumineers are very thin porcelain veneers that generally used for cosmetic procedures. A broken tooth usually requires more extensive restorative options. See your dentist for specific options.

You Have Options: Depends on the amount of missing tooth. You may be able to get it fixed with a filling or a veneer. Btw, lumineers is a type of veneer just like crest toothpaste is a brand of toothpaste.

Success of Veneers: Successful results with veneers is very dependent on the quality and extent of the bond made between the porcelain and enamel of the tooth. Bonding between porcelain and dentin is weaker. Deep or extensive damage to the tooth resulting in exposure of the dentine under the outer enamel is usually a valid indication for full coverage with a crown (cap).

Thanks for asking!: Personally, I am not a fan of lumineers. There are plenty of ways to fix a broken front tooth with esthetic bonding, some times all porcelain crown or a porcelain veneer. The best way is to do minimal preparing but with no prepping of the tooth it will look bulky.

Many options: Many options exist for your situation. The most conservative would be resin/composite bonding. It will discolor and is less durable than ceramic veneers or feldspathic porcelain, but it is the most minimally invasive and least costly. Check with your dentist.