Hyoid Displacement During Swallowing Function for Completely Edentulous Subjects
Condition: Prosthesis Durability
MeSH terms: Prosthesis Failure
Study type: Interventional

Summary: 
      To investigate the effect of wearing mandibular implant retained overdentures on superior and
      anterior hyoid displacement during swallowing process.
    

Detailed description: 
      New conventional complete denture with optimal flange extension and well established
      lingualized balanced occlusal scheme was constructed for every patient. To construct the
      radiographic stent, clear acrylic resin duplicate for the mandibular denture was constructed,
      several small holes were made on the polished surface of the duplicate. These holes were
      filled with radio-opaque gutta-percha points to act as a reference points during
      determination of the quantity of available bone for implant placement and for construction of
      stereolithographic surgical guide.

      Cone beam computerized tomography [i-CAT] was used to construct the stereolithographic
      surgical guide by applying dual scan technique. By using the surgical guide, two dental
      implants (Dentium implants, 12-14mm in length, 3.6-4mm in diameter, Superline II) were placed
      in the canine regions of the mandibular arch with guided surgical protocol. The patients were
      instructed to take prophylactic antibiotic two times a day (875mg Amoxicillin and 125mg
      Clavulanic acid) 24 hours before the surgery and continue after the surgery for seven days.
      Non-steroidal anti-inflammatory drug was used to control the pain.

      After surgery, the complete denture was withdrawn, and the patient was instructed to eat soft
      diet. After one week, the mandibular denture was relieved and relined with Cold- curing
      silicon based relining material (Softliner, PROMEDICA). The dentures were delivered to the
      patients and follow up visits were scheduled. After three to four months, the dental implants
      were exposed, and the healing abutments were secured to the dental implants. After healing of
      the soft tissue (7-10 days), the healing abutments were removed, and ball attachments
      (Dentium ball abutment, Superline II) were screwed to the dental implants. Direct pick-up
      technique was used to incorporate the housing of the attachments into the fitting surface of
      the mandibular denture using self-cured acrylic resin material. The occlusion of the
      overdenture was evaluated to eliminate any premature occlusal contact then the overdenture
      was delivered to the patient.

      Videofluroscopic swallowing study (VFSS):

      All subjects were examined by using videofluroscopic swallowing study to evaluate bolus
      movements. This evaluation was done at three different oral conditions, without complete
      denture (WCD), after 2 months of conventional complete dentures insertion (CDs), and after 2
      months of implant overdenture insertion (IODs). Each patient was instructed to swallow 10 ml
      of thin liquid {20% barium sulfate (Prontobario H.D®) and 80% water} three times. The records
      of the videofluroscopic swallowing evaluation were saved to the computer for later analysis.
      A software Program (EO Program) was used to placing timing on the frame of the video (1/100
      second) and analyze the recording by frame by frame data analysis.

      a- Spatial measurements: Superior hyoid displacement (vertical movement) and anterior hyoid
      displacement (horizontal movement) were measured according to dynamic swallowing study
      performed by Rebecca Leonard & Katherine Kendall during pseudo rest position and during
      maximum overall hyoid displacement .24 Aline was drawn from anterior superior point of
      cervical spine 4 (p1) contacting anterior inferior point of cervical spine 2 (p2) and
      extended superiorly as necessary, then another line was extended from the anterior, inferior
      portion of the hyoid bone to meet the P1-P2 line at 90-degree intersection. The Measurement
      from the P1 to the intersection point (Hsup-rest) and from hyoid bone to the intersection
      point (Hant-rest) were recorded then the video was advanced until the hyoid bone showed
      maximum overall displacement and the previous procedure was repeated. The measurements from
      P1 to the intersection point (Hsup-max) and from the hyoid bone to the intersection point
      (Hant- max) were recoded. The difference between the maximum hyoid position (Hsup-max) and
      the pseudo rest position (Hsup-rest) in the vertical direction was called the superior hyoid
      displacement, while the difference between maximum hyoid position (Hant-max) and pseudo rest
      position (Hant-rest) in the horizontal direction was called anterior hyoid displacements.

      B- Temporal measurements:

        1. Duration of hyoid maximum elevation (DOHME):

           Measured from the first frame showing maximum hyoid elevation to last frame showing
           maximum hyoid elevation.

        2. Duration of hyoid maximum anterior excursion (DOHMAE):

      Measured from the first frame showing maximum anterior hyoid movement to last frame showing
      maximum anterior hyoid movement.

      C- Penetration / aspiration scale:

      Penetration was defined as the food bolus enter the airway down to the vocal folds, while
      aspiration defined as the food bolus enter the airway below the level of the vocal folds.

      0= No penetration or aspiration

        1. Penetration

        2. Aspiration
    

Intervention name(s): implant overdenture; videofluroscopy
Intervention type(s): Procedure; Radiation
Intervention description(s): . Videofluoroscopy swallowing evaluation was done using 10 ml of thin liquid bolus at three different oral conditions: Without dentures (WOD), with the conventional complete denture (CDs) and with mandibular implant retained overdenture (IODs).; videofluroscopy evaluation of swallowing function
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Hyoid bone.; implant.; overdenture; swallowing.