Comparison of Changes in Intraoral Dynamic Space (Donders Space) with Myofunctional Therapy in Skeletal Class II Division 1 Malocclusion: An In Vivo Study.

AIM: To evaluate the changes in the intraoral dynamic space with myofunctional therapy in skeletal class II division 1 malocclusion using three-dimensional digital volume tomography (3D-DVT). MATERIALS AND METHODS: The study type is observational and the duration of intervention was 3 years. Dental casts obtained from 20 samples of 11-14 years age-group were collected and 3D-DVT scans were performed prior to and after the myofunctional therapy. The parameters depicting the arch perimeter, arch width, arch length, arch shape, and arch volume on dental cast were used in the study using several linear and volumetric measurements. All parameters were compared before and after myofunctional therapy using t-test. RESULTS: The Intraoral volume before myofunctional therapy (T0) was 5.59 mL and after myofunctional therapy (T1), it was 7.22 mL. Significant changes were seen in intraoral volume, arch perimeter, arch length, and intercanine and intermolar arch width and the arch shape. Linear and volumetric measurements were increased after myofunctional therapy. CONCLUSION: Myofunctional appliances lead to an expansion in the anteroposterior and sagittal direction thus increasing the Donders space and leading to proper formation of dental arches and proper positioning of the teeth. CLINICAL SIGNIFICANCE: Myofunctional therapy is an effective method of increasing arch width, length, and volume. This therapy can be used in routine practices in young children with constricted arch and improvement in facial esthetic.

Application of a barometer for assessment of oral functions: Donders space.

We developed a barometer applicable to a small space, to assess oral and pharyngeal functions. Negative oral pressure during rest and pressure changes during swallowing were measured in a space between the palate and tongue (STP). Twenty volunteers were asked to sit in a chair in a relaxed upright position. A sensor was placed on the posterior midline of hard palate. Recording commenced just before subjects closed their lips and continued. Subjects were asked to swallow saliva and keep the apposition. Finally, subjects were asked to open their mouth. Recordings were performed five times, and 5 s of continuous data in each phase was averaged. To verify the reliability of the system, the same procedure was accomplished with twin sensors. When the jaw and lips were closed, the pressure slightly decreased from atmospheric pressure (-0·17 ± 0·24-kPa). After swallowing, the pressure in STP showed more negative value (-0·50 ± 0·59-kPa). There is a significant difference between the values in open condition and after swallowing (P < 0·001) and between values after swallowing and final open condition (P < 0·05). Twin sensor showed almost the same trajectories of pressure changes for all the recordings. Obtained negative pressure might generate about 0·71-N of force and would be enough to keep the tongue in the palatal fossa at rest. The system detected large negative/positive pressure changes during swallowing. We conclude this system may be a tool to evaluate oral functions.