Non-invasive 3D facial analysis and surface electromyography during functional pre-orthodontic therapy: a preliminary report

Abstract

Objectives:Functional orthodontic devices can modify oral function thus permitting more adequate growth processes. The assessment of their effects should include both facial morphology and muscle function. This preliminary study investigated whether a preformed functional orthodontic device could induce variations in facial morphology and function along with correction of oral dysfunction in a group of orthodontic patients in the mixed and early permanent dentitions.Material and Methods:The three-dimensional coordinates of 50 facial landmarks (forehead, eyes, nose, cheeks, mouth, jaw and ears) were collected in 10 orthodontic male patients aged 8-13 years, and in 89 healthy reference boys of the same age. Soft tissue facial angles, distances, and ratios were computed. Surface electromyography of the masseter and temporalis muscles was performed, and standardized symmetry, muscular torque and activity were calculated. Soft-tissue facial modifications were analyzed non-invasively before and after a 6-month treatment with a functional device. Comparisons were made with z-scores and paired Student's t-tests.Results:The 6-month treatment stimulated mandibular growth in the anterior and inferior directions, with significant variations in three-dimensional facial divergence and facial convexity. The modifications were larger in the patients than in reference children. In several occasions, the discrepancies relative to the norm became not significant after treatment. No significant variations in standardized muscular activity were found.Conclusions:Preliminary results showed that the continuous and correct use of the functional device induced measurable intraoral (dental arches) and extraoral (face) morphological modifications. The device did not modify the functional equilibrium of the masticatory muscles.

Relation between facial morphology on lateral skull radiographs and sEMG activity of head, neck, and trunk muscles in Caucasian adult females

“…Although an example of crosstalk is seen in frontal sEMG recordings when the patient clenches the teeth (Cram and Kasman, 1988), we positioned the ground electrode on the forehead because we used a similar protocol to other researchers (Tartaglia et al, 2009;Siéssere et al, 2009;Ferla et al, 2008;Tecco et al, 2008).…”

Relationships between craniofacial morphology and masticatory muscle activity during isometric contraction at different interocclusal distances

“…The distance between each participant and a digital camera (Nikon, Tokyo, Japan) was 2 meters. The following anatomical structures were traced as follows ( inter-pupil distance / facial width ratio (P-P/Zy-Zy) and face width / face height ratio (Zy-Zy/N-Me) (Tartaglia, Grandi, Mian, Sforza, & Ferrario, 2009).…”

Reaction of facial soft tissues to treatment with a Herbst appliance

“…Furthermore, most studies have been based on two-dimensional (2D) variables from lateral cephalograms [10,24,30]. Only a few three-dimensional (3D) studies have been published so far, and they have been limited to investigating changes in the soft tissues brought about by removable functional jaw orthopedic appliances [19,21,33]. Those studies have reported a correlation in the therapeutic effect between cephalometric values and 3D soft tissue data [19,21].…”

“…Die meisten Studien basieren auf zweidimensionalen Variablen der Fernröntgenseitenbilder [10,24,30]. Nur wenige 3D-Studien sind bislang publiziert, und in diesen wurden ausschließlich die Veränderungen der Weichgewebe durch eine Therapie mittels herausnehmbarer funktionskieferorthopädi-scher Apparaturen untersucht [19,21,33]. In zwei Therapiestudien konnte eine Korrelation zwischen kephalometrischen Werten und 3D-Weichteildaten ermittelt werden [19,21].…”