Further Validity and Reliability of Turkish Version of the Mandibular Functional Impairment Questionnaire in Patients with Temporomandibular Dysfunction

Abstract

Purpose: 
 The aim of this study is to develop a new Turkish version of MFIQ (MFIQ-T-N) by adding the cut off value and improving the validation to the Turkish version of the Mandibular Functional Impairment Questionnaire (MFIQ-T) in patinets with Temporomandibular dysfunction.
 Methods: The psychometric properties of the MFIQ were examined in 242 participants diagnosed with TMD and 81 healthy participants. The internal construct validity was assessed with both exploratory and confirmatory factor analysis. External construct validity of the MFIQ-Tr-N was established by The Fonseca Anamnestic index (FAI), The Oral Health Impact Profile-14 (OHIP-14), and The patient health questionnaire-9 (PHQ-9). Predictive validity was examined using the receiver operating characteristic (ROC) to validate the cut-off value of the MFIQ-T-N for diagnosis of TMD. For the determination of reliability internal consistency, test-retest reliability and smallest real difference (SRD95) were investigated. 
 Results: Factor analysis indicated that the MFIQ-T-N had three factors as masticatory, non-masticatory 1, and 2. The MFIQ-T-N was moderately correlated with the FAI (Spearman’s rho = 0.553, p < .001) and OHIP-14 (rho = 0.534, p < .001). The cut-off point for MFIQ-T-N was set at >5 with 84% sensitivity and 87% specificity. The ICC and Cronbach’s α values were found as 0.913 and 0. 916, respectively. The SRD95 for Test-retest reliability was 7.004. 
 Conclusions: The MFIQ-T-N had sufficient psychometric features and was appropriate to use for participants with TMD. In addition, this new version provides researchers with greater opportunities to evaluate mandibular functions in the TMD patient group.