Determinated area (DA) treatment goal when treating malocclusions with jaw functional orthopedics (JFO): Contribution to scientific evidence

1. Introduction

Planas since his first publications in late 50’s and early 60’s stated that the incisive proprioception brings better results when treating malocclusion with neuro-occlusal rehabilitation [1]. He defended the thesis that when the mandible is free to move and during its lateroprotrusive movements or protrusive movements the buccal face inferior incisors touch the palatine face of the superior incisor the contact will trigger better development stimuli to the stomatognathic system (SS). It is good to remember that in Planas’ treatment protocol the ideal stimulation is the freedom of mandibular movements and the advances the mandible and keeps it forward in very specific cases [1, 2].

There are several protocols of therapeutic mandibular posture change (TMPC) with functional appliances depending on the type of malocclusion being treated [3]. It is postulated by Simões that when you construct the FOA TMPC and get the touch of the buccal surface of the inferior incisors in its incisal third against the palatine surface of the superior incisors in its incisal third – touch in DA – it is achieved the "supreme neural stimulation" for the treatment of malocclusions. Planas. The aim of this investigation is check, with surface electromyography of bilateral masseter, temporal and suprahyoid muscles, the stimuli improvement when the TMPC reach DA touch if it can be considered as a deal for malocclusions treatments with FOA, and if sEMG is a trustable tool to analyze masticatory muscles function for Diagnosis, Treatment and evaluation post treatment/ gained objective.

2. Methodology

Using a basis formed by 159 patients under treatment in Specialization course. The protocol followed the course to diagnosis, planification, and treatment includes: Anamnesis, Physical and Functional examination, normal lateral tele radiography (with Bimler and Petrovic cephalometry), tele radiography in NHP (Normal Head Position) (with Rocabado Cephalometry), Gnatostatic casts, mouth and body photos and films, sEMG collected in three times (Diagnosis, Appliance installation, D.A. obtained: Determined Area ) by three ways (Diagnosis- isometric contraction, FOA installation and fifteen minutes after this. sEMG examination follow ISEK protocol (bilaterally registration), and used no Normalization, all sEMG signals were analyzed from zero (rest) until the finish (15 seconds). All above data constructed the Tripled List to Diagnosis, Priorities and Treatment (Sakai & Corsi 2005). Appliances were made following instructions contained on Simoes. After obtained D.A., sEMG data were done again in three conditions: rest, isometric contraction with FOA and without it, under same Ambiental conditions (especially electromagnetic area isolation. Materials to sEMG: conditioning signals module from Lynx Electronics Ltda with 8 channels, model EMG1000; software AqDAnalysis 4,18 from Lynx Electronics Ltda.; Software Lynx BioInspector 1,8r; passive surface electrodes (Ag/AgCl) from Noraxon Dual Electrodes (USA); dischargeable reference electrodes Kendall Meditrace (Ag/AgCl) – Canada . Frequency calibration was 2000 Hz, with 2048 sample by channel and time 1,024 seconds, and filters regulation was 20 Hz and 1000 Hz. This investigation, authorized by the Research in Humans Ethics Committee of Universidade Estadual de Campinas (UNICAMP), Piracicaba, Brazil under protocol 159/2004.

In this study, patients were evaluated in 3 situations: Diagnosis – Diagnosis session (T1), Functional Orthopedic Appliance (FOA) -the day of functional appliance placement on the mouth (T2) and Determined Area (DA) – when patient maintains the touch between buccal face of inferior incisor against the palatine face of upper incisor without the appliance (T3), and each moments combination justify pairing because same patients were evaluated on 3 conditions what suggest association degree between data observed. For Pared Data it´s usually apply Student’s T test, Wilcoxon Test and Signal Test. Due to size of the sample (less than 2000), Shapiro-Wilk Test was used, because the sample has a normal distribution at significance level of 5 %.

Grouping analysis were applied to create patient groups with same result, in opposition to patients that show different results in order to evaluate groups and explain different comportments based on distinct morphometrics characteristics and diagnosis/prognosis; these characteristics cannot be controlled at time to choose experimental patients. It was used average grouping method based on data averaged. Method average linkage works with not pondered groups pairs method, using arithmetic average using middle distances.

3. Results

Obtained D.A., third sEMG data were done, in Rest, Isometric Contraction with and without FOA. After some statistical treatment, adequate to biological data, were found that D.A. is a good and important goal to malocclusions treatment with JFO. Results showed that functional mandible movements were equal, and sEMG profile were equilibrated bilaterally in all cases, moments, and situations. And more, for first time were obtained Rest registration with results closer to zero (centesimal of microvolt).

Commentary 1: The Signaled Order Test is recommended because there is no normality signals ($p=$0,0044), but symmetry, that reveal statistically strong signals ($p=$0,00195) of differences between real medias on T3 and T2 from right suprahyoid muscle. Difference of media is negative and show that RMS values observed on T2 are bigger than on T3.

Commentary 2: Student’s T test shows statistically significant different signals ($p=$0,00320) of true amplitudes on T3 and T2 from right suprahyoid muscle. The difference of media is negative, and RMS values observed on T2 are more heterogeneous than observed on T3 phase.

Commentary 3: Student’s T test show signal statistically significant difference ($p=$ 0,00365) from real media on T2 than on T1of right temporalis muscle showing smaller signal amplitude on T2 concluding that RMS values of T1 are bigger than T2.

Commentary 4: Signal Test reveal true amplitudes signals shows statistically significant difference ($p=$0,01367) between T1 and T2 on left masseter muscle. This difference is positive, and because of this RMS values on T2 are more heterogeneous than on T1.

Commentary 5: Student’s T test shows statistically significant difference ($p=$ 0,01406) between true patterns deviation on T2 and T1 from left masseter muscle. RMS values observed on T2 are more heterogeneous than on T1.

Commentary 6: Student’s T test shows statistically significant difference ($p=$0,01508) between true amplitudes on T2 and T1 from right suprahyoid muscle show more heterogeneity on T2.

Commentary 7: Student’s T test shows statistically significant difference ($p=$ 0,02073) between true amplitude on T2 and T1 form left suprahyoid muscle showing more heterogeneity on T2 than T1 on the signals similar of the finding on the right side.

Commentary 8: Student’s T test shows statistically significant difference ($p=$0,03336) between true pattern deviation on T2 and T1 from left suprahyoid muscle; this difference is positive, and because of this RMS values observed on T2 are more heterogeneous than observed T1.

The recordings of Isometry tests with respective results are shown in Table 2. Look that right temporalis muscle shows significative difference from all parameters (Media, Pattern Deviation and Amplitude) when analyzed the numbers in FOA and Diagnosis periods.

It can be observed that these differences are always negative indicating that medium values and variability are always bigger on T1. Other difference is on left temporalis muscle: difference signal between true medias from T3 and T1, showing media from T3 significantly bigger than T1.

4. Discussion

Acceptable is to any malocclusions treatments have a deal, an objective, something concrete. The D.A. announced by Planas on first time for decades ago, shows a different way to obtain results and understand stomatognathic system and its functions, especially mastication. But this kind of postulate need for some researchers, investigations with scientific method, and publications. This is a final part of our investigation started with some case reports, methodology tests, Ambiental and laboratory installations, materials. Is D.A. an adequate deal for malocclusions treatments with FOA? With D.A. muscles involved obtain bilaterally balance? Some care were used (registration form rest until rest, no uses of Normalization, use best materials, sEMG registration obtained bilaterally, lab isolated to electromagnetic influences). Some investigations made years ago, suffered with analogic signals and analysis: Ahlgren, Ingervall and Thilander [4] studied and compared electromyographic activity from temporalis, masseter and orbicularis oris from patients with normal occlusion and with malocclusion Class II on rest, mastication and deglutition. Concluded that there are no differences in rest position between groups. There are agree on conclusion verified EMG activities differences in bilateral registrations, the results published by Moyers [5], Pruzanski [6], Quirch [7], Moss [8], Deguchi et al. [9], Gerstner et al [10], Palomari-Tobo et al [11]. It´s understood that these differences show us muscular function executed by different ways between right and left sides. Our data showed bigger Amplitudes, Pattern-Deviation and Media on isometric situation in Masseter on side of Minimal Vertical Dimension (MVD) [1,2] and anterior part Temporalis of opposite side (contralateral). These variations are according Planas’s affirmations [2] based on clinical observations. On the other hand, the findings are according to reported by Jarabak [12]; Pancherz and Anehuis [13]; Carels and van Steenberghe [14]; Mushimoto and Mitani [15]; Okeson [16] showing muscular adaptation to stomatognathic system changes.

Following ISEK and SENIAM orientations, with digital registrations and analysis gave to sEMG an higher scientific status. Level and number of scientific publications actually are higher than never; and because of it were assumed these cares. Results obtained and analyzed by some statistical tests and analysis gave consistency to these finds. And this research was not limited to results of a technique: some different appliances were used to these treatments, all of them FOA applied according to patients’ necessities; status of Stomatognathic System across and at the end of treatment are fundamental [1, 2]. Because of all of these, optioned to publish this investigation with all data, analysis, report (statistical), based on idea to stimulate other investigations. Electromyography is a seductive muse because it provides easy access, in detriment, electromyography is too easy to use and consequently too easy to abuse De Luca [17].

5. Conclusions

In D.A. were found a bilateral equilibrium of sEMG registration of the studied muscles, due to a homogenization of bilateral muscle analyzed results,

In D.A. were found a diminishing the sEMG registration in Amplitude, Pattern Deviation and Media, in all situation and moments, giving validation to D.A. as a treatment objective.

sEMG is a trustable tool to analyze masticatory muscles function for Diagnosis, Treatment and evaluation post treatment/ gained objective.