Jaw Function and Oral Health-Related Quality of Life : Relation between Temporomandibular Disorders and otherOral Conditions
Authors:   , Oghli Ibrahim 
Published: January 2025

The focus of this thesis was two major patient-reported outcomes: quality of life and jaw function. Different study designs were used to examine the prevalence, impact, and predictive factors of orofacial conditions, with a focus on temporomandibular disorders (TMD) and their effects on oral health-related quality of life (OHRQoL). The findings in the different parts of the thesis provide a comprehensive understanding of the burden these conditions reflect on individuals, particularly when they occur in combination.

Orofacial conditions such as TMD, burning mouth syndrome (BMS), dry mouth, and bad breath were found to be prevalent in the Swedish adult population, with bad breath being the most commonly self-reported condition. Notably, individuals experiencing multiple conditions, which affected more than a quarter of the population surveyed, demonstrated significantly higher impairments in OHRQoL, illustrating the compounded negative effects of comorbid conditions. TMD and BMS, in particular, were associated with the most substantial impact on quality of life, emphasizing the difference between painful and non-painful conditions.

Limitations in jaw function, another key focus, were generally low among the Swedish adult population. However, age and the presence of dental prostheses were identified as significant predictors of increased limitations. This highlights the importance of considering both demographic and dental factors when evaluating jaw function. The study also established normative values for jaw function, offering a benchmark for clinical assessment of orofacial dysfunction. A score of 28 or higher on the Jaw Functional Limitation Scale was found to have clinical significance.

In terms of orofacial pain conditions, including TMD, odontogenic pain, oral mucosal pain, and pain following third molar extractions, were all found to have a moderate impact on the pain dimension of OHRQoL. The highest burden was observed in patients with pain after 3rd molar extraction, although all four pain conditions resulted in a notable reduction in quality of life. This standardized understanding of the pain-related impact on OHRQoL provides critical insight for clinicians managing patients with various orofacial pain syndromes.

Longitudinal analysis of TMD patients revealed that the physical component of health-related quality of life (HRQoL) over time is significantly predicted by baseline factors such as age, general health, and jaw function. Older age and poor general health were associated with worse physical HRQoL in painful TMD cases, whereas impaired jaw function was particularly relevant in non-painful TMD cases. Interestingly, no significant predictive factors were identified for the mental component of HRQoL, suggesting the need for further research into the psychological dimensions of TMD and other orofacial conditions.

Overall, this thesis provides evidence that orofacial conditions, particularly TMD, have a significant and multidimensional impact on both oral and general quality of life. By integrating cross-sectional and longitudinal data, this work offers valuable insights into the epidemiology, functional consequences, and long-term predictors of quality of life in individuals with orofacial conditions.