FUNCTIONAL OCCLUSION AFTER FIXED APPLIANCE ORTHODONTIC TREATMENT - A UK 3-CENTER STUDY

This study aimed to assess the prevalence of functional occlusal conta cts in cases treated to a Class I incisor relationship by upper and lo wer fixed appliance therapy. Helkimo's dysfunction indices were used b y one examiner to assess mandibular mobility, clinical dysfunction and occlusal status. One-hundred-and-eighty-eight subjects participated i n three UK orthodontic centres; Cardiff, Newport and Liverpool. The re sults show that RCP (CR)-ICP (CO) discrepancies occurred in 33 (18 per cent) cases, non-working side contacts were present in 31 per cent an d posterior contacts on protrusion occurred in 44 (23 per cent) subjec ts. These interferences were significantly more frequent in cases trea ted by postgraduate students compared with those treated by staff clin icians (P< 0.05). An overbite greater than 2.4 mm resulted in a highly significant reduction in the occurrence of non-working side contacts and posterior protrusive contacts (P< 0.001). The prevalence of functi onal occlusal discrepancies in this UK sample of orthodontic cases is similar to that reported in the American literature.