A systematic review of patient-oriented outcomes following complete denture treatment: a comparison between the neutral zone technique and conventional approach

To determine the patient-oriented outcomes after complete denture (CD) treatment using neutral zone (NZ) techniques compared with those of conventional dentures.

Electronic and hand searches were conducted up to December 2023 based on PICOS criteria. Population (P) was patients with complete edentulism on maxillary and mandibular arches and were either or not wearing CDs. Intervention (I) focused on the fabrication of mandibular and/or maxillary CD using NZ techniques. Comparators (C) included other CD fabrication approaches, such as conventional and simplified techniques, and the use of old or existing CDs. Outcomes (O) were patient-oriented treatment outcomes. Study design (S) included human studies.

Eleven human experimental studies were included. NZ dentures demonstrated better patient-reported outcomes, by providing greater comfort, enhancing denture stability and retention, reducing food traps underneath the denture, as well as improving appearance, chewing efficiency and speech. Objective findings varied, with most studies showing equivalent outcomes for NZ and conventional dentures. However, one study indicated superior, and another demonstrated worse outcomes for NZ dentures.

NZ dentures generally improve patient-reported outcomes more than conventional dentures. However, their impact on objective outcomes compared with a conventional denture remains uncertain.