The post-orthodontic prevalence of temporomandibular disorder and functional occlusion contacts in surgical and non-surgical cases

This study aimed to assess mandibular mobility and the prevalence of functi onal occlusal contacts in subjects treated to a Class 1 incisor relationshi p by fixed orthodontic appliance therapy. Two hundred and thirty subjects p articipated (mean age = 18 years) of whom 42 underwent orthognathic surgery . All subjects were in retention with a mean time of 7 months between debon d and examination. Maximal mandibular opening, lateral and protrusive excur sions were all significantly reduced in the surgical cases compared to the nonsurgical group. Centric and eccentric non-ideal occlusal contacts were n ot different between surgical and non-surgical groups. Non-working side con tacts occurred in 30% of subjects, posterior contacts on protrusion in 20% and RCP-ICP prematurities in 18% of subjects. Non-working side contacts wer e significantly more frequent in post-graduate cases compared to staff case s (P < 0.05). An overbite less than the mean of 2.4 mm resulted in a reduce d likelihood of canine guidance on the working side (P < 0.001) and an incr eased frequency of non-working side contacts and posterior contacts on prot rusion (P < 0.001).