Svrha rada bila je utvrditi koliko pojedina vrsta protetske terapije utječe na OHRQoL i koliki udio ima poboljšanje estetike, a koliki poboljšanje funkcije žvakanja. U istraživanju je sudjelovalo 770 ispitanika. U testiranju psihometrijskih svojstava hrvatskog prijevoda OES upitnika (za procjenu izgleda orofacijalne regije) sudjelovalo je 144 ispitanika. Prilikom razvoja novog jednodimenzijskog upitnika za procjenu funkcije žvakanja i u testiranju psihometrijskih svojstava, sudjelovala su 424 ispitanika. U ispitivanju utjecaja različitih vrsta protetske terapije na poboljšanje estetike, funkcije žvakanja i OHRQoL, sudjelovala su 202 ispitanika. Svi podaci statistički su analizirani programom SPSS 19.0 for Windows. Primijenjene su metode deskriptive statistike, t test za nezavisne i zavisne uzorke, one-way ANOVA (Sheffe post-hoc), korelacijske i regresijske analize, te faktorska analiza za formiranje upitnika i za redukciju faktora. Hrvatski prijevod modificiranog OES upitnika pokazao je dobra psihometrijska svojstva. Za procjenu funkcije žvakanja stomatognatog sustava, formiran je faktorskom analizom novi jednodimenzijski upitnik, koji je također pokazao dobra psihometrijska svojstva. Rezultati su pokazali da nije bilo značajne razlike između muškog i ženskog spola, ni prije, ni poslije provedene protetske terapije za estetiku, žvačne funkciju i OHRQoL. Sve vrste terapija (konvencionalna ili, na implantatima, totalna ili djelomična proteza, fiksni rad sa ili bez implantata, kombinirani rad) značajno su poboljšale, i estetiku, i žvačnu funkciju, i OHRQoL. Najveća veličina učinka terapije na poboljšanje estetike zabilježena je u pacijenata koji su dobili mostove na implantatima, djelomične proteze retinirane kopčama i retinirane implantatima te totalne proteze retinirane implantatima. Najveća veličina učinka terapije na poboljšanje funkcije žvakanja i poboljšanje OHRQoL zabilježena je u pacijenata koji su dobili totalne i djelomične proteze i mostove na implantatima. Analizirajući promjenu statusa stomatognatog sustava provedenom protetskom terapijom, najveća veličina estetskog učinka protetske terapije, bila je promjena iz bezubog statusa u mobilnu protezu. Najveći učinak terapije na poboljšanje žvakanja i OHRQoL bio je prilikom promjene iz mobilnog ili bezubog stanja u fiksni rad (most na implantatima) ili iz bezubog statusa u totalnu protezu. Utjecaj poboljšanja estetike i žvačne funkcije na poboljšanje OHRQoL nije bilo moguće dobro procijeniti (mali postotak utjecaja estetike), što je pripisano neadekvatnošću OHIP14 upitnika za procjenu estetike (ne sadrži dovoljan broj relevantnih pitanja koja se odnose na estetiku orofacijalne regije). Esthetic and functional impact of a proshodontic treatment to the oral health related quality of life Purpose: The aim was to evaluate influence of esthetic and functional impacts on increase of OHRQoL caused by different types of prosthodontic therapy. Materials and Methods: A total of 770 individuals participated. In assessment of psychometric properties of the Croatian version of the OES questionnaire 144 subjects participated. In development of a new unidimensional questionnaire for a self-assessment of chewing function and in assessment of its psychometric properties, 424 subjects were included. Finally, 202 prosthodontic patients were included to reveal how different types of prosthodontic therapy improve esthetics, chewing and OHRQoL. Statistical analysis was performed by SPSS version 19.0 for Windows. Descriptive statistics, independent and dependent t-tests, one-way ANOVA (Sheffe post-hoc), regression and correlation analysis were performed. Factor analysis was used to measure dimensionality of the questionnaire and for data reduction. Results: The psychometric properties of the Croatian modified version of the OES questionnaire were excellent. A new unidimensional instrument for assessment of chewing function was developed by factor analysis and it showed satisfactory psychometric properties. There was no significant difference considering esthetics, chewing and OHRQoL between males and females, neither before, nor after prosthodontic treatment. Each type of prosthodontic therapy conventional or implant retained complete denture (CD, CDI) or removable conventional or implant retained partial denture (RPD, RPDI), conventional or implant supported fixed partial dentures (FPD, FPDI) significantly improved esthetics, chewing and OHRQoL. The highest improvement of esthetics (highest treatment effect size) was found in FPDI patients, followed by the RPDI or RPDs with precise attachments and then by CDI. The highest treatment size effect on chewing function and OHRQoL was found in patients who received CDI, followed by RPDI and FPDI. The results of conversion of dental status by a prosthodontic therapy showed the highest improvement of esthetics in patients who were edentulous (ED) and received removable dentures (RD). The highest improvement of chewing and OHRQoL was registered in patients who were edentulous (ED) and received CDs and in patients who replaced CDs with FPDIs. Conclusion: The influence of esthetics (unexpectedly low percantages) and chewing function on the improvement of OHRQoL was not possible to evaluate adequately, which was attributed to inadequate OHIP14 questionnaire for assessment of esthetics (it included not enough relevant questions related to the esthetics of the orofacial region).