The distinction between four-implant and six-implant full-arch rehabilitation is frequently presented to patients as a matter of price. It is more accurately a matter of biomechanics, with cost as a consequence.
The rationale for four
The four-implant protocol employs two axial anterior implants and two posteriorly tilted implants, permitting engagement of available anterior bone and avoiding anatomical structures such as the maxillary sinus and the inferior alveolar nerve.
Its principal advantage is the frequent avoidance of grafting procedures, with consequent reduction in both cost and treatment duration. Long-term survival data for the protocol are favourable.
The rationale for six
Six implants distribute occlusal load across a greater number of supports and reduce cantilever length distally, which is mechanically advantageous in patients exhibiting high occlusal forces or parafunction.
Six implants additionally provide redundancy: the loss of a single fixture in a six-implant reconstruction may be manageable, whereas in a four-implant reconstruction it typically compromises the prosthesis.
Selection criteria
Bone volume and quality, opposing dentition, documented bruxism, arch being treated, and the material of the planned prosthesis all inform the decision. The maxilla, having lower bone density than the mandible, more frequently indicates additional support.
The determination should follow cross-sectional imaging and occlusal assessment, not patient budget.
Cost implications
Two additional fixtures and abutments increase both the surgical and the prosthetic component of the fee. The increase is proportionately smaller than patients often assume, since the prosthesis represents a substantial share of the total.
Where the additional implants are clinically indicated, the incremental cost is modest relative to the consequences of prosthetic failure in an inadequately supported reconstruction.
To determine whether this procedure is indicated in your particular case, we invite you to request a clinical assessment.
