All-on-4-implants or all-on-6-implants causes spitting and hissing?

Hi, thank you for your question. Regarding removable dentures opposed to a fixed All-on-4 or All-on-6 prosthesis, we see many more problems with removable dentures than we see with fixed prosthesis. Removable dentures are very difficult to keep in your mouth and are poorly retained. You will have much more difficulty with speech and hissing. Stability and retention of teeth makes a big difference for chewing and speaking. You will find that a fixed prosthesis feels a lot more natural. Good luck! 

Information you have is incorrect. Hissing and spitting only occur if there is a space underneath the restoration

An all on 4 (TM) is a much superior restoration, it maintains the bone, doesn't move, allows you to eat what you want, enhances confidence. I can go on and on as to why they are better than dentures. To gain a sucessful outcome attention to detail is imperative

I hope you find this answer well. It's not always the case that All-on-4 or 6 result in hissing and spitting. In fact, there are some patients who receive the treatment and have no trouble with speaking. However, even with the best dentures, patients will experience bone resorption. The dissolving jaw bone due to lack of stimulation that is produce by tooth roots or implants. In all, many patients with dentures, inevitably experience  caving in of the face which can appear that ones nose is closer to their chin.

The spitting and hiss when talking happens if the prosthetic teeth are not in the right position this can happen with all types of solutions including dentures and the all-on-4 solutions.  Whats important is that the teeth are designed and positioned where they need to be in your mouth and that the bridge is touching the upper gum such that air does not go through that space.  You have many options removable overdentures, fixed bridge on 4-6 implants or more conventional bridgework with 6-8 implants.  All these solutions can be amazing or have issues, you best choose the right provider.Good luck!

I think the opposite is true. Less hissing and spitting with the All-on-Four because of the better fit and less movement of the replacement teeth. If you don't want a removable solution, the All-on-Four is one of your best options.