Introduction: The objective was to compare the cervical spine postural changes after treatment with fixed and removable functional appliances. Methods and Analysis: A retrospective study with pre and post lateral cephalograms of 60 patients was planned. They were divided into three groups- fixed functional appliance, removable functional appliance and a control group which involved camouflage mechanics. Cervical spine posture and airway were assessed. The craniocervical angulation changes were correlated to changes in ANB, mandibular parameters and airway. Results: Amongst the cervical spine postural variables, only the sella-nasion to odontoid process tangent (SNOPT) showed significant changes (Twin block/control, p=0.041). Removable and fixed functional appliances brought about a reduction in the SN-OPT. However, this was not statistically significant (Herbst/control=0.184; Herbst/Twin block, p=0.761). Control group revealed an increase in the SN-OPT and this difference was significant between Twin block and control group (p=0.041). There were significant variations in the SNB (p=0.000) and ANB (Herbst/control, p=0.003; Twin block/control, p=0.001) between both Herbst and Twin block groups when compared with control group. However, there were no significant differences between the Herbst and Twin block groups (SNB, p=0.333;ANB,p=0.974). There were no significant differences in the mandibular length and the mandibular plane angle between the three groups (mandibular length, p=0.206; mandibular plane angle, p=0.788). Changes in superior, middle and inferior pharyngeal airway were not significantly different between the three groups (p=.537; p=.354; p=.110 respectively). Conclusion: The functional appliances did not affect significant changes in the cervical spine posture. There were no significant differences between fixed and removable functional appliances.
Ganesan et al. (Fri,) studied this question.