In Vivo Assessment of Natural Tooth Color After Orthognathic Surgery. A Pilot Controlled Clinical Trial
Condition: Discoloration, Tooth
MeSH terms: Mouth, Edentulous; Tooth Discoloration
Study type: Interventional

Summary: 
      In six consecutive patients planned to receive combined orthodontic-orthognathic surgery
      natural tooth color on 8 incisors was measured before initiation of the combined treatment
      (Time Point 1- baseline) and after its completion (Time Point 2- after intervention). The
      statistical interpretation of the results showed that tooth color change in the surgical
      group was higher in comparison to control groups. Control group I included non treatment
      subjects, while control group II included standard orthodontic treatment subjects. The
      results indicated that orthognathic surgery may affect natural tooth color but to small
      degree, as the color differences were just bellow the threshold value of 3.7 ΔΕ units. Under
      this value a color change cannot be easily detected by a human eye.
    

Detailed description: 
      The method of natural tooth color assessment included the use of the spectrophotometer
      Spectroshade Micro (MHT Zurich, Switzerland), which is a reflectance spectrophotometer with a
      LED technology light source with an output of 410-680 nm that is transformed into
      monochromatic light (λ = 400-720 nm) by means of grating. On this type of spectrophotometers,
      light is split so that teeth can be illuminated simultaneously from two sides at a 45° angle
      with the use of an intra-oral camera. The reflected light is directed at 0° on two detector
      areas (each detector area surface is of 18 x 13 mm2). One detector area is a color CCD chip
      responsible for the generation of the colored video image. A black-and-white CCD detector
      area records the spectrophotometric data. During a measuring process, light originating from
      the monochromator of the device is emitted in 10-nm intervals. Resulting images consist of
      300,000 pixels. Initially, CIE tristimulus values are calculated and then converted to
      CIE-Lab values with the use of the accompanying software. Prior to every measuring cycle, the
      spectrophotometer had to be calibrated to a white and a green ceramic tile that are
      incorporated on the base of the device by the manufacturer.

      Assessments were performed with closed lips in order to exclude disturbance by daylight. In
      order to avoid methodical errors in the assessment of luminance teeth of the upper and lower
      dental arches were not in contact, thereby obtaining a uniform black background by the oral
      cavity without an overlapping of anterior teeth. Tooth color was measured in the study and in
      the control groups at Time point 1 and Time Point 2. To enhance reliability of the method two
      sequential pictures of each tooth (Left + Right) were obtained with the use of the
      spectrophotometer and imported to the dedicated MHT Spectroshade software v3.01 Build 1007a
      (MHT Zurich, Switzerland), licensed to Aristotle University (Station ID: 952317337-Serial NR
      LUA164-164-164). Using the synchronization tool followed by the synchronous measurement tool,
      the cursor was accurately positioned on the center of the clinical crown on both pictures
      simultaneously, and the software reported color measurements for both pictures. The cursor
      shape was a circle, while the size was set at 100 pixels. Due to the synchronization of the
      pictures, the cursor area was exactly the same for both. To consider the method reliable, the
      maximal allowed color difference between the two consecutive pictures, was set at ΔΕ≤1.
    

Intervention name(s): Combined orthodontic-orthognathic treatment; Standard orthodontic treatment
Intervention type(s): Procedure; Procedure
Intervention description(s): combined treatment including orthodontics and orthognathic surgery; treatment with standard orthodontic procedures
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: The trial includes a study group of patients receiving orthognathic surgery. It is divided into two subgroups. Subgroup I including bimaxillary surgical patients with Le-Fort I osteotomy for the upper jaw and sagittal split ramus osteotomy for the lower jaw. Subgroup II including patients receiving mandibular surgery only. Finally, two control groups were applied. Control group I including no treatment subjects and Control group II including standard orthodontic treatment subjects
Masking: None (Open Label)
Primary purpose: Screening
Keywords: Tooth color changes; Orthognathic surgery; Spectrophotometer