Nocturnal Mouth Guards, SOVA vs. Standard Acrylic Orthotic; Phase IV
Condition: Sleep Bruxism; Tooth Wear
MeSH terms: Bruxism; Sleep Bruxism; Tooth Wear
Study type: Interventional

Summary: 
      Clinical trials of bite splint use and night time tooth grinding have not been performed.
      Consequently, there are no definitive outcome measures or efficacy standards that can be
      applied to large clinical trials. The present preliminary trial will determine what objective
      measures can be used to evaluate efficacy. The outcome variables will fall into four
      categories: (1) fabrication efficacy, (2) compliance, (3) functional efficacy, and (4) user
      satisfaction. The immediate goals will: (1) focus on the over-the counter SOVA night guard,
      (2) conduct tests under controlled clinical conditions using the 'gold standard', the acrylic
      'bite splint' or 'orthotic', hereafter called the "Michigan bite splint", to compare the
      performance and efficacy of the SOVA night guard. Subsequent studies will be able to use the
      outcome variables identified in this study for broader clinical trials.

      Specific Aim 1. To compare the SOVA night guard to the custom-acrylic Michigan bite splint in
      clinical laboratory conditions. Hypothesis: There will be no significant differences between
      the devices in terms of fabrication efficacy, functional efficacy or user satisfaction.

      Specific Aim 2. To compare the SOVA night guard to the custom-acrylic Michigan bite splint
      under ecologically relevant conditions, i.e., the home environment. Hypothesis: There will be
      no significant differences between the devices in terms of compliance or functional efficacy.
    

Detailed description: 
      Subjects. Sample size estimations are based upon a recent review of randomized clinical
      trials, in which acrylic appliances were evaluated (see Appendix 2 in (Huynh et al., 2007)).
      The mean +/- 1 standard deviation (SD) number of bruxism episodes per hour with a Michigan
      bite splint was 3.97 + 0.58, and for a palatal splint, the mean +/- 1 SD was 4.45 + 0.63.
      Using these means and the higher SD (0.63), along with an alpha = 0.05 and beta = 0.8, a
      study would be sufficiently powered with sample sizes of 29 per group. Based on other
      Michigan studies, wherein recruitment, exclusion and attrition rates are known, it is
      estimated that an initial screening sample size of 120 will be necessary to end up with 29
      per group.

      There will be two treatment groups: a group receiving supervised training in the fabrication
      of the SOVA night guard (SOVA) and a group receiving the Michigan custom-acrylic bite splint
      (MI BS). Two groups times 29 subjects per group equals 58 total needed for analysis.

      Care will be taken to match the randomized groups for age, ethnicity, gender and
      temporomandibular disorders (TMD) signs/symptoms. Alternatively these will be modeled as
      nuisance variables if attrition rates create bias or there is a lack of sufficiently sized
      screening pools.

      Screening. Candidates will undergo a screening to assess co-morbidities and to identify
      inclusion and exclusion criteria. Standard questionnaires and screening instruments and a
      brief clinical exam will be performed. Subjects meeting the acceptance criteria will be
      randomly assigned to one of the two groups using stratified randomization procedures (Suresh,
      2011). Alginate impressions will be taken, and impressions poured in stone. The models will
      be used either to fabricate the MI BS or to assess SOVA appliances for fabrication efficacy.

      Splint delivery. For the SOVA group, subjects will be asked to fabricate SOVA devices in the
      clinical laboratory while receiving feedback from trained and calibrated study 'instructors'.
      Fabrication will use manufacturer instructions. Calibrated instructors will be blinded to the
      study's objectives, as will subjects. A "Michigan" acrylic bite splint will be fabricated
      using standard clinical practice and checked for fit and quality on subjects assigned to the
      MI BS group.

      Subjective fabrication assessment. Standardized questionnaires and box scales will be used to
      assess ease of fabrication, ease of instructions, and other related issues for the devices.

      Quantitative fabrication assessments. Four aspects of fabrication will be evaluated by
      investigators: (1) stability-does the device move independently of the maxilla and is the
      mandible stabilized by the device, (2) retention-does the device resist displacement, (3)
      tissue adaptation-how much spacing exists between the maxilla and the device and between the
      device and mandible, and (4) health of the teeth, gingival, tongue, palate and lips.

      Stability and retention will be quantitatively assessed with jaw movement (MaxTraq motion
      analysis system, Innovision, Columbiaville, MI) and electromyography (EMG) (LabChart,
      ADInstruments, Colorado Springs, CO) data and force sensors. For position-stability
      assessment, maxilla, mandible and the splint will be simultaneously recorded from at least
      three sites to capture 6 degrees of movement freedom. Subjects will clench, grind, perform
      closed border movements and vacuous chewing (verified with EMG and force sensors). For
      retention assessment, subjects will perform a series of tests designed to dislodge the
      device, e.g., tapping, forced blowing, coughing, chewing on gum. Stability and retention
      indices will be created based on whether device movements vary independently of jaw movements
      and applied bite forces, and how force sensor output varies during dislodgement exercises.
      Deviations will be used to form standardized indices of stability and retention, with smaller
      values representing greater stability and retention. Note that a major part of the study will
      be to develop the appropriate methods to make these measurements, as it is not clear how this
      should be done ideally.

      Tissue adaptation will be assessed by 3D laser scanner. The occlusal, facial and lingual
      surfaces of the upper arch will be scanned as will the inner surface of the night guards. An
      index of adaptation will be developed based on the volumetric spaces separating the teeth
      from the device, using topological software. Smaller volumes will represent better tissue
      adaptation. Volumetric indices will be compared between devices via ANOVA or appropriate
      statistical methods. Note that a major part of this study will be to develop an accurate and
      precise way of measuring volumetric spacing, as such methods have not yet been developed.

      Tissue health will be assessed via appropriate, standard methods currently used in cariology
      and periodontology clinical studies (Monse et al., 2012; Tirapellia et al., 2010). Baseline
      measurements will be compared with post-device wear measurements. Between-group differences
      will be studied with a repeated measures ANOVA or appropriate statistical methods.

      Compliance assessment. Compliance assessments will focus on: (1) how often the device is
      worn, (2) whether the device is removed at inappropriate times during the night, (3) whether
      alternative devices are used. Compliance will be assessed via subject self-report, nocturnal
      EMG recording devices and microwear methods. Subjects would be blinded to the purpose of the
      technological methods. Occlusal microwear patterns are unique to the surfaces against which
      occlusion occurs, and the microwear changes on a daily basis (Ungar et al., 2003). Hence,
      microwear assessment should provide definitive evidence of splint compliance. Microwear
      analysis methods will be developed as part of this study for these purposes.

      Functional efficacy. Two questions will be addressed under functional efficacy: (1) does the
      device alter bruxing activity, and (2) how do the teeth and device hold up under bruxing
      activity. Some of the technology used for compliance assessment, above, can be used here.
      Gold standard methods for evaluating bruxing activity rely on polysomnography (PSG) and EMG
      activity; therefore, it these technologies will be used as well. To address the second
      question, how do the teeth hold up, 3-D laser scanning technology will be developed and used
      to measure changes in macroscopic tooth structure, and confocal microscopy and
      scale-sensitive fractal analysis will be assessed for utility in diagnosing microwear.

      User satisfaction. This will be assessed through a series of standardized questionnaires
      adopted from other clinical studies, e.g., the Oral Health Impact Profile (Slade and Spencer,
      1994), the Tampa Scale for Kinesiophobia: TMD (Visscher et al., 2010), the TMD pain screener
      (Gonzalez et al., 2011). Questionnaires used in the SISU field tests (SISU mouthguards
      preliminary results), as well as forced choice, box scales and statistical methods developed
      in another study (Lin, 2008; Lin et al., 2013) will also prove useful for assessment of
      patient satisfaction. Also questions such as, does the device hurt or pinch anywhere, does
      your bite feel 'off' when you first remove the guard, etc. will be used to assess specific
      aspects of user satisfaction.

      Repeated measures (Week 1 check-up and 4 Month check-up). Compliance, stability, retention,
      tissue adaptation and health, functional efficacy and user satisfaction will be assessed two
      times, viz., 1 week after delivery and 4 months after delivery. This will provide a rigorous
      data set, reduce subject attrition and thus allow for both publications and further clinical
      trials to be pursued.
    

Intervention name(s): SOVA Bite Splint; Michigan Bite Splint
Intervention type(s): Device; Device
Intervention description(s): Over-the-counter thermoplastic bite splint blank, heated, molded to fit.; Heat-cured acrylic bite splint fabricated by dentist/dental technician to fit
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: dental orthotic; bite splint; oral parafunction; clenching; grinding