Validity and reliability of the Turkish version of the 20‐item jaw functional limitation scale

ABSTRACT

Purpose

This study aimed to translate the 20-item Jaw Functional Limitation Scale (JFLS-20) into Turkish (JFLS-20-TR) and investigate the psychometric properties of the JFLS-20-TR.

Methods

This study included 232 patients with temporomandibular disorder (TMD) and 130 individuals without TMD. Structural (with confirmatory factor analysis [CFA]), convergent (with pain intensity, Fonseca Anamnestic Index [FAI], and Oral Health Impact Profile [OHIP-14]), discriminant (with maximum mouth opening [MMO]) and known-group validity were investigated to assess the construct validity. Cronbach’s alpha for internal consistency and the intraclass correlation coefficient (ICC_2,1) for test-retest reliability were calculated. Additionally, content and face validity, smallest detectable change (SDC₉₅), and floor/ceiling effects were evaluated.

Results

According to CFA, the model fit indices were acceptable for JFLS-20-TR, confirming structural validity. Strong correlations were found between the global and subdomain scores of the JFLS-20-TR and pain intensity (r ≥ 0.80), FAI (r ≥ 0.83), OHIP-14 (r ≥ 0.76), and MMO (r ≥ −0.79) scores, confirmed the convergent and discriminant validity of the JFLS-20-TR. In addition, JFLS-20-TR differentiated between patients with TMD and individuals without TMD (p < .05). Internal consistency (Cronbach’s alpha values: 0.91–0.93) was excellent, and test-retest reliability (ICC_2,1 values: 0.91–0.95) was high. Content and face validity were satisfactory. The SDC₉₅ values ranged from 0.79 to 1.43. No floor or ceiling effects were observed.

Conclusion

The JFLS-20-TR is a valid, reliable, and useful tool for assessing jaw functional limitations in Turkish-speaking patients with TMD.

KEYWORDS:

• Masticatory system
• temporomandibular disorder
• questionnaire
• reliability and validity
• factor analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.