Efficiency of Two Occlusal Splints on TMD Treatment of Police Officers
Condition: Stress, Psychological; Temporomandibular Disorder
MeSH terms: Temporomandibular Joint Disorders; Temporomandibular Joint Dysfunction Syndrome; Stress, Psychological
Study type: Observational

Summary: 
      Stress is an important cause factor of temporomandibular disorder (TMD) and Police Officers
      are exposed to stress. Aim of the study was to evaluate clinical and electromyographically
      the effect of two different occlusal splints on police officers with TMD
    

Detailed description: 
      After the approval by the Human Research Ethics Committee of the Piracicaba Dental School by
      the register number 189/03, 905 police officers of the São Paulo State - Brazil filled up the
      Axis II of Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and 256
      volunteers were selected with TMD symptoms. Afterward the volunteers were submitted to the
      Axis I of RDC (clinical examination) and were excluded who presented systemic diseases like
      fibromyalgia, arthritis, arthrosis or osteoporosis, historical of TMJ (temporomandibular
      joint) surgery or TMD treatment, dental prosthesis, loss of more than two posterior teeth
      (except third molars and teeth extracted for orthodontic reasons), incomplete dentition with
      spaces in the arch (except third molars),volunteers with orthodontic and/or orthopedic
      appliances, with mandible and/or maxilla fractures, vertebrae or medullar canal stenosis,
      taking anti-inflammatory, analgesic and/or muscle-relaxing drugs, in otologic treatment or
      without compromise with the investigation. Who presented myogenic or mixed TMD, TMJ pain for
      at least three months and joint tenderness on palpation on at least one side was invited to
      remain in the study.

      According to the exclusion and inclusion criteria above presented were selected 30 volunteers
      (15 women and 15 men), average age of 29 years, with diagnosis indicative of myogenic or
      mixed TMD.

      The volunteers were randomized divided into three different groups with 10 persons per group
      using a stratification method performed by computerized table that placed the subjects into
      different groups according to the occlusal splints. Group A: Not received any oral device
      (Control); Group B: Used Michigan Occlusal Splint (MOS);Group C: Used Planas Oral Appliance
      (POA).

      Each one of the 30 volunteers filled out the Visual Analog of Pain Scale (VAPS) to evaluate
      the muscle pain sensibility and were clinically examined according to the Axis I of RDC,
      always by the same examiner, in the morning, before and four weeks after the beginning of the
      experiment.

      OCCLUSAL SPLINTS Twenty volunteers used two different occlusal splints during four weeks only
      while sleeping.

      Volunteers were oriented to not communicate each other during treatment to keep unknown the
      differences between occlusal splints and about the control group.

      Instrumentation Electromyographic records were performed on temporal, masseter and suprahyoid
      muscles before and four weeks after used the occlusal splints. Volunteers remained seated,
      Frankfurt's plane parallel to the floor, looking toward the front, feet on the floor, legs at
      90º angle and hands resting on thighs. Occlusal splints were removed during EMG records.

      All EMG records were obtained by Lynx Data Acquisition System (MCS1000-V2) with 16 channels,
      12 bits resolution of dynamic range, Butterworth filter, 500 Hz pass band, high pass filter
      of 20 Hz and gain of 2000 times. The Software Aqdados, version 5 (Lynx) was used, with a
      sampling frequency of 1000 Hz and simple differential active surface electrodes with entrance
      impedance of 10 ohms CMRR (Common Mode Rejection Reason) of 80 dB, impedance of 1012 ohms and
      gain of 20 times. A reference electrode was positioned on the sternum bone of the volunteers.

      Surface electrodes were placed bilaterally on the masseter, temporal and suprahyoid muscles,
      according to previous muscles palpation and muscle function test. In all cases electrodes
      were fixed on the previously cleaned skin by alcohol and attached by double-side adhesive
      tape (Castroflorio et al., 2004) in the centre of the muscular belly, parallel to the muscle
      fibers with the silver bars perpendicular to their direction to maximize signal capture and
      minimize noise interference.

      In three different moments the EMG records were performed. First: 5 seconds of muscle
      resting. Second: maximal voluntary contraction (MVC), biting bilaterally two pieces of
      elastic cord (no.201) of 2.5-cm length. Third: MVC for the suprahyoid muscle at maximal mouth
      opening (MMO). Signals were normalized by the mean of the RMS (Root Mean Square) of three MVC
      measurements. Each EMG exam was performed after 3 minutes of resting for physiological
      recovery avoiding muscle fatigue.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        police officers of the São Paulo State - Brazil filled up the Axis II of Research
        Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) with TMD symptoms.
      
Keywords: stress, temporomandibular disorders.