Veneers are good for front 80% broken tooth? or resin bonding?

Neither possibly: 80% is an awful amount of tooth loss. A composite filling is only recommended when there is up to 50% or less of tooth loss. As you asked in your last question and the # was 25% which is ok for a composite. Depending on the tooth loss whether it is horizontally missing or circumferential makes a difference. I would have to see the tooth, but you may end up with a crown and possible nerve exposure.

Should be crown: If 80% of the tooth is missing your best solution is a full crown probably with a buildup to replace some missing tooth structure for a better base to hold the crown. A veneer is not recommended and resin bonding would be a temporary restoration at best.

At least a Crown!: If the tooth still has good bone support and health gums, at the very least i would recommend a crown. Anything less and you are probably just throwing you money away, especially for bonding. It's hard to make these calls without actually seeing your mouth clinically along with some x-rays of the area. Your dentist can give you the best advise (hopefully).

80% is a lot: If 80% is gone, you may need a build up, retained by posts, pins, and/or root canal on top of that...A bonding would definitely not be long term.

Veneer or crown: Thank you for posting your question. The tooth was grossly fractured. Resin bonding will not provide enough strength and durability to chewing force. Veneer is a better choice. However, your dentist will have to evaluate the condition of your tooth and bite to decide a veneer or a crown should be used to restore it. Hope this helps and good luck!

Broken tooth: Resin bonding can provide immediate repairs, however, they are not as strong/duable as a laboratory fabricated custom porcelain restoration.

See your dentist: After evaluating health history, current dental health, and the condition of a patient's enamel, a dentist can make an informed decision regarding a placement of proper restoration. See your dentist ASAP.

See a dentist: The choice of the prosthetic is dictated by a number of different factors that are evaluated during an exam. Your bite, depth of fracture, bone support, and position of the tooth all play a role. Bonding would not be my material of choice in replacing 80% of a missing tooth. The material is just not that strong.