With All-on-4 dental implants, what's the best and most natural-looking material for the teeth: ceramic, porcelain, or zirconia?

The 3 options you have listed are all similar..All on 4's are usually done with porcelain or very hard nonstainable plastic imbedded in a pink gum colored resin...This is a very attractive choice and the least expensive..Zirconia teeth and gums is another option affording usually a longer lasting overlay with less chance for breakage and repair..The Zirconia option is probably the most esthetic but you should have your dentist show you cases he(she) has performed using both materials and you choose. Good luck.

The most natural looking material is either porcelain or zirconia, they are more expensive but can definitely look better. 

Wonderful question!
The best materials will depend on several factors such as your teeth alignment,  bite forces (history of clench or grind habits), cosmetic concerns, and whether or not the opposing teeth are natural and what condition they are in. Zirconia is definitely the hardest material and is very durable and has very good aesthetics.  Porcelain ceramic will give the highest cosmetic result but can be more expensive.  Another option is hybrid composite which combines high aesthetics with a hardness that will not damage opposing teeth.  It also has the advantage of being repairable in the mouth.  Acrylic bonded to a metal bar was the original All-on-4 material and is still used in some situations but has the highest rate of breakage and wear. I hope this helps you to make the best decision for your needs! 

The two most common materials used in All on 4 style cases are acrylic and zirconia. Although zirconia tends to give the most pleasing aesthetic result, it is a very hard material. Consideration must be given when both arches are being restored. It has been reported that when zirconia teeth on the top are opposing zirconia teeth on the bottom, it can actually produce a clicking sound when speaking. Another concern is that such none-yielding materials can transfer stress to either the abutment connection or the implant itself. Proper diagnosis and treatment planning should be done on a case-by-case basis. It wouldn't be a bad idea to consider zirconia teeth on the top for aesthetics and acrylic teeth in the bottom to cushion the force. 

Hello 1joel2u, 
The most life-like material that we have in dentistry today is porcelain. Remember that porcelain and ceramic are the same for the purposes of our conversation here. A dentist will use the terms interchangeably. 
In regards to All-on-4 dental implant treatments, the choices are - Acrylic Teeth, Porcelain Teeth, or Zirconia Teeth or a combination of the above. The strongest of all with the least amount of complications is zirconia. It also comes VERY VERY close to the aesthetics of a porcelain crown that the naked eye cannot discern the difference. 
It is also important to keep in mind that one material doesn't solve all problems. Some patients are not zirconia candidates so I highly recommend you see a prosthodontist (prosthetic specialist) for an evaluation and proper planning.
I hope that answers your question. 

Joel, 
We make All on 4 bridges out of two different materials, and both can be very natural looking:
1)  Acrylic fused to a titanium frame:  Very nice looking, but over the years the acrylic can chip and wear and require repair and replacement. 2) Zirconia:  Very strong and seldom chips or needs repair - currently cost more than the acrylic.

Great question, where multiple factors should be considered. 
1. The most economical option is a Titanium bar with acrylic teeth. The quality of the teeth can be different , with multiple layers, fluorescence, texture. Acrylic teeth will wear out as well, faster if opposing dentition are crowns or natural teeth and slower if it is another set of acrylic teeth. When that happens they will need to be replaced.
2. Zirconia Hybrid Bridges - made entirely from monolithic zirconia, pink porcelain or composite can be added for aesthetics. if layered with porcelain could be very beautiful and natural. Issue is that the bridge is very heavy, almost like you having an Iphone between your teeth:)
3. Titanium bar with separate Emax Crowns. With this and next option we are entering the land of "artistic" dentistry. Very few dentist use this options, because of the fees and the precision needed. Titanium bar is designed like individually prepared teeth and separate porcelain crowns are fabricated for each tooth. Gum shades are added and the results are amazing. Texture, contour, shades, characterization and lots of love will make the case exceptional.
4. Pekkton bar with LiSi or Emax crowns and Anexdent pink composite is at the moment the most beautiful restoration possible for all on 4 cases. New generation of very strong composite structure, extremely hard but very light and flexible. if someone is interested on aesthetic hybrid bridges , this should be number one choice. Fees are higher , because every detail is crafted manually by true artist and many hours are spend to create it.

The best material to use for natural looking teeth would be acrylic.  The pigmentation's, translucency, as well as shade give the smile a fresh, natural, smile line.  Many of our patients receive compliments about there smile, people ask them what tooth paste they use because of how beautiful there teeth look.  Many people ask our patients if those are there real teeth and our patients are so tickled on how much people notice there how natural there smile looks and is. 

Thanks for the question. The most aesthetic all on four prosthesis is the Zirconia hybrid. There is usually an upgrade fee to go with Zirconia, but it will look the most natural and it is the strongest out of all the materials you listed. 

In most circumstances I find the acrylic all on four to give the most natural look and wear character.  I will often use zirconia when just doing one arch and opposing natural teeth for strength.  These look very nice as well.