Why Can't a Replaced Lumineer Look and Feel the Same As the First Installation?

If your new Lumineer feels bulkier than the the first one, it's probably because not all the cement from the first one was removed and so the second one is placed over a "thicker" tooth.  If color and texture are different, that's because different technicians fabricate Lumineers and so there will be some variation.  High resolution pictures of the adjacent Lumineers with correct lighting taken from various angles should be sent in to ensure a better match.  Hope this helps.

When you need to replace a single veneer, especially a front tooth, it can be difficult to get exactly the same color/texture match as what was likely done in a grouping.  This has mostly to do with batches of porcelain being different now than four years ago. Having said that, it should be possible to make a new veneer with new impressions, and good photography by your dentist, so the dental laboratory technician knows exactly what your dentist (and you!) are hoping to achieve.

My concern would be why the veneer chipped in the first place. This is most likely caused by one of two reasons.  Bad habits like biting fingernails, chewing ice,  or opening packages with the teeth are often the culprit. However, much of the time we find there is an imbalance in the patient's bite, causing tooth grinding and/or uneven wear of the teeth.  If either of  these is the culprit, the veneer will likely fracture or fall off again...which is frustrating for everyone involved.

Make sure your dentist very carefully checks your bite for imbalance before replacing your veneer, and if your habits are to blame...change them! Good luck!