Abstract: PURPOSE: This clinical study was to evaluate oral health-related quality of life (OHRQoL) changes in patients who underwent all-on-4 treatment in one or both jaws. METHODS: Eleven patients underwent placement of 4 to 6 dental implants on the basis of all-on-4 treatment concept in the maxilla, mandible or both jaws and immediate loading with acrylic interim prostheses. The prostheses were replaced after 3-6 months, and definitive prostheses with metal framework and reinforced resin facing were fixed after another 3 months or more. The subjects completed the shortened Chinese version of the Oral Health Impact Profile (OHIP-14) before surgery (T0), 1 week after interim prostheses were placed (T1) and 3 months after definitive prosthesis placement (T2). The data of 11 subjects were analyzed with Wilcoxon signed-rank test using SPSS 13.0 software package. RESULTS: The total OHIP-14 score significantly reduced only at T2 (P<0.05). "Functional limitation," "physical pain," "physical disability," and "psychological disability" scores significantly decreased at T2, and "psychological discomfort" scores also significantly dropped at T1. "Social disability" and "handicap" scores remained unchanged throughout the treatment course. CONCLUSIONS: Fixed definitive prostheses with metal framework are more effective in improving OHRQoL than fixed acrylic prostheses during all-on-4 treatments.

Key words: All-on-4 treatment concept, Immediate loading, Fixed complete dental prosthesis, Dental implants, OHRQoL, OHIP-14