Children with Juvenile Rheumatoid Arthritis (JRA) rarely report temporomandibular joint (TMJ) pain, which may be due to pain avoidance mechanisms resulting in compromised masticatory function. This study examined the relationship between self-report measures of pain and dysfunction and measures of chewing performance in 44 JRA children and 34 normal controls.
The children were divided into three groups: Group 1, JRA children with temporomandibular joint disorder (TMD); Group 2, JRA children without TMD; Group 3, normal control children without TMD. Both visual and analog scales of jaw pain, ability to chew, and quality of life were administered before and after chewing tasks. Children chewed standardized portions of an artificial food for 20 cycles and expectorated the particles into a cup. This process was repeated five times. Median particle size and a broadness of particle distribution index were measured. Also, the number of chewing cycles prior to the child's first swallow for a cube of carrot was recorded.
The broadness of particle distribution index was greater for Group 1 (P < 0.001) and Group 2 (P < 0.03) than for Group 3 with no difference in number of chews for carrot mastication among groups. Group 1 reported more pain and dysfunction before the chewing tasks than Groups 2 or 3 (P < 0.05). Interestingly, only Group 3 reported increased pain and decreased ability to chew after chewing tasks (P < 0.02).
Children with JRA compromise their masticatory function as a pain avoidance mechanism. Such findings may have profound implications with regard to the nutritional status for these children.