6 or 4? How many implants are required for a full arch?

I am often asked by patients seeking full arch replacement teeth whether they require 4 dental implants or 6. The answer to this is case specific and I will aim to explain this in this blog.

When considering replacing a full arch of teeth with dental implants there are usually 2 main options. Patients can either opt to have a removable implant retained denture or a permanently fixed implant supported bridge. There are sub categories within these 2 options however, for the purpose of this blog it is fair to divide these options into 2 main categories.

The implant retained denture option often requires 2-3 dental implants in the lower arch and 4 dental implants in the upper arch. The key to making this option work is to provide sufficient implant support for the denture to be stable in the mouth during function. The implant retained denture is removable and will exhibit slight movement at times however, in the main it is very stable and signifcantly more stable than a conventional denture without any implant support.

A fully fixed and permanent implant supported bridge is what many patients opt for if they do not want to have removable teeth. In most cases, this option can utilise between 4-6 dental implants. The number of implants required will be based upon many local and anatomical factors. Firstly, we must consider the number of teeth and size of teeth required in the individual. Every mouth is different and every person’s requirements are different as well. In an ideal situation we want to ensure we provide enough teeth to fully occlude with the opposing arch. Therefore, if one has 12 teeth in the opposite arch then we must provide at least 12 teeth to occlude against these. Also, we must provide enough teeth to fill the overall smile and look in-keeping with the patient’s natural facial profile and appearance. For example, it would look odd to give someone with a larger mouth small teeth and vice versa.

Secondly, we must carefully assess the anatomy on the CBCT scan. The amount of bone available and the quality of the bone is key to deciding how many dental implants will be necessary to provide stable and long term support for the replacement teeth. A weaker bone structure would often require more dental implants (eg 6) to provide a better implant – tooth ratio and allow for an even spread of the occlusal forces and stresses on the teeth. One must remember that although the dental implants are incredibly strong, they are only as strong as the bone into which they have been placed. Therefore, overloading on an implant can cause it to come away from the underlying bone and eventually fail. We provide bone augmentation treatment alongside the implant treatment to strengthen our patient’s bone and the foundations into which the implants are placed.

For these reasons, some of our full arch cases use 4 dental implants whereas others use 6 dental implants. There isn’t a generic answer to how many are required and we always aim to minimise the number of dental implants where required as long as it does not compromise the quality of the treatment. All of our consultations are thoroughly provided to provide a customised plan to every patient pursuing one of the most life changing dental procedures.

Thank you for reading,

Mohsin Patel