Temporo-mandibular joint kinetics and chewing cycles in children. A 3-year follow-up.

OBJECTIVES

To report the temporo-mandibular joint (TMJ) kinetics and masticatory function in healthy children.

DESIGN

Temporo-mandibular joint palpation and electrognathographic registrations of chewing cycles were repeated for 3 years in order to evaluate changes.

SETTING

Healthy children without systemic pathologies, decayed cavities and previous dental treatment.

SAMPLE AND

METHODS

Electrognathographic (EGN) registration of masticatory cycles and TMJ palpation were carried out on 52 patients (mean age: 5 years 8 months, range: 5 years 1 month, 6 years 8 months), by two university researchers, once a year for 3 consecutive years. TMJ palpation, differentiated TMJ synchronism (simultaneous bilateral opening movement) and TMJ asynchronism (not simultaneous bilateral opening movement), TMJ subluxation and click were observed. Electrognathographic registrations differentiated normal and abnormal jaw chewing cycles, and narrow and large cycles.

RESULTS

Temporo-mandibular joint asynchronism was evident in 34 of 52 patients in the primary dentition, in 42 of 52 patients after the eruption of the first permanent molar, and in 31 of 52 patients after the eruption of the permanent incisors. TMJ subluxation increased during the full period of observation. Three temporomandibular clicks appeared after the eruption of the permanent incisors. Altered mastication was not always associated with TMJ disorders.

CONCLUSIONS

In children, normal chewing cycles can coexist with occlusal discrepancies, cranio-facial growth and TMJ alterations.