Mandibular movement characteristics of an anterior disc displacement with reduction.
OBJECTIVE
According to the Research Diagnostic Criteria (J Craniomandib Disord 1992;6(4):301-355), an anterior disc displacement with reduction (ADD) is characterized by reciprocal clicking with the opening click occurring at a mouth opening at least 5 mm greater than that of the closing click. The aim of this study was to test whether the 5-mm criterion of the RDC is characteristic for a click due to an ADD.


METHODS
From 30 participants with a unilateral ADD, recordings of mandibular movements with 6 degrees of freedom as well as joint sound recordings were made. The participants performed free open movements and loaded closing movements.


RESULTS
In 8 joints (27%), the 5-mm criterion was not fulfilled. For 2 participants, the click while closing occurred with an even larger mouth opening than that while opening. Recordings of the condylar movements showed that the opening clicks occurred over a broad range of the opening movement, whereas all the closing clicks occurred just before the condyle reached its terminal position in the fossa.


CONCLUSIONS
The 5-mm criterion of the RDC is not characteristic of all anterior disc displacements with reduction.
Huddleston Slater
James J R
JJ
Department of Oral Function, Section Craniomandibular Disorders, Academic Centre for Dentistry, Amsterdam (ACTA), Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Lobbezoo
Frank
F
Naeije
Machiel
M
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001314:Auscultation; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis*; D016014:Linear Models; D008297:Male; D008335:Mandibular Condyle / Q000503:physiopathology; D008875:Middle Aged; D009068:Movement; D012015:Reference Standards; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D019224:Temporomandibular Joint Disc / Q000503:physiopathology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis*