Evaluation of Digital Versus Conventional Techniques for Construction of Mandibular Implant Retained Overdenture
Condition: Occlusal Wear of Teeth
MeSH terms: Tooth Attrition
Study type: Interventional

Summary: 
      The aim of this study is to evaluate of two different construction techniques (digital and
      conventional techniques) for two implant retained complete mandibular overdenture regarding:

      1. Digital occlusion stability detection: evaluated by using OccluSense.

      Evaluation was done in the following evaluation period:

      T0: Immediately after over denture insertion. T6: 6 months after over denture insertion. T12:
      12 months after over denture insertion.
    

Detailed description: 
      Patient selection and study design:

      Six patients who required complete denture were selected from the diagnostic clinic of
      Prosthodontic Department, Faculty of Dentistry, Mansoura University. All patients were
      informed about the procedures that was done and a written consent form of ethical committee.
      All patients had the right to withdraw from the study at any time.

      Patients Grouping:

      Patients were divided in to 2 equal groups:

      Group (I): 3 patients received maxillary CD and mandibular 2-implant retained overdenture
      constructed by digital technique.

      Group (II): 3 patients received maxillary CD and mandibular 2-implant retained overdenture
      constructed by conventional technique.

      Surgical phase procedures:

        1. Preoperative investigations of the patient were done that included the blood profile
           (hemoglobin, complete blood (cell) count, bleeding time, clotting time, random blood
           sugar).

        2. Preoperative assessment of mandibular bone was done radiographically by cone beam
           computerized tomography (CBCT).

        3. Each patient received two dental implants in the canine area bilaterally.

        4. All implants were placed according to the flapless protocol.

        5. A customized surgical stent fabricated according to the preoperative computer based 3D
           plan and used during the surgical procedure to ensure accurate implant position and
           angulation.

        6. A small round bur (or Guide drill) the first drill used to make a hole of 1-2 mm deep to
           create a start point for the pilot drill.

        7. The pilot drill is the first twist drill used to create the osteotomy up to the desired
           length.

        8. The drills should be repeatedly pumped in and out of the osteotomy to expose the bone
           debris to the water coolants for clearing.

        9. A guide pin should be placed in the prepared site to check alignment and parallelism.

       10. Subsequent drills were used in the same way as the pilot drill to enlarge the osteotomy
           to the desired depth.

       11. Profile drills or countersink drills were used to widen the crestal part of the
           osteotomy to allow the next drill into the osteotomy and to allow the placement of the
           cover screw without any bony interference.

       12. Osteotomy was performed through the sleeves of the surgical stent and the implants were
           placed by hand using a torque wrench (35-45 Ncm) through the sleeves. the implant placed
           0.5 mm slightly subcrestal, and cover screws were secured using Hex driver.

       13. The dentures were molded to not interfere with the peri-implant tissues and reduce
           occlusal forces on the implant.

      After 3 months of osteointegration period, the implants were exposed, the cover screw was
      removed and the two healing abutments were screwed into the fixture using their driver for 7
      to 10 days.

      Each patient received maxillary complete denture against mandibular 2- implant retained
      complete overdenture with two different construction techniques.

      The clinical procedures in the respective visits are described below:

      Steps of conventional complete overdenture construction:

        1. For each patient in group two, preliminary maxillary and mandibular impressions were
           made using irreversible hydrocolloid impression material and stock impression trays.

        2. on custom trays border molding performed by using a thermoplastic compound green sticks.

        3. The maxillary definitive impressions were made by using a zinc oxide impression
           material.

      6. The mandibular definitive impressions were made by direct impression technique with the
      aid of impression post and laboratory analogue.

      7. Models were poured with implant analogues; the definitive locator attachment was screwed.

      8. Fabrication of maxillary and mandibular record blocks were done and the labial fullness
      was established, occlusal plane, and occlusal vertical dimension was recorded and the
      reference lines (midline and canine line) was marked on the wax rims.

      9. Centric jaw relation was registered. Using face bow, upper cast mounted and then centric
      relation recorded.

      10. Selection of teeth was done by using the readymade artificial acrylic teeth with
      lingualized occlusal scheme. And setting of teeth was done with bilateral balanced occlusion.

      11. Try-in, processing, finish and polish of the dentures were done.

      Digital complete overdenture construction:

        1. For each patient in group one, preliminary maxillary and mandibular impressions and
           poured with dental stone in casts and custom trays were fabricated.

        2. Border molding performed. The maxillary and mandibular definitive impressions were made.

        3. Models were poured with implant analogues; the definitive locator attachment was
           screwed.

        4. Scanning for the model was done to achieve 3D virtual image to the models.

        5. Fabrication of maxillary and mandibular record blocks were done and the labial fullness
           was established, occlusal plane, and occlusal vertical dimension was recorded and the
           reference lines (midline and canine line) marked on the wax rims and the resultant data
           was scanned.

        6. The file of this master scan in STL format transmitted to the CADCAM complete denture
           provider using a purpose-built software program.

        7. The anatomic landmarks identified, and the peripheral limits marked on a virtual model
           in the design software, which then was served to design the definitive denture base.

        8. A virtual tooth arrangement was generated for a digital preview.

        9. The digital preview was evaluated and modified if necessary.

       10. Transfer data to a CAM software program, the prostheses printed, finished and polished.

      Insertion the prosthesis into the patient's mouth and have them bit down until the resin has
      cured. Remove the prostheses and trim the excess resin. The prosthesis delivered and patient
      instructed about the aftercare and recall schedule steps.

      Evaluation

      Digital occlusal stability detection:

      Group I and group II subjected to test by utilization of the Digital Occlusal Analyzer System
      (OccluSense). The occlusal forces distribution, extent and time sequence can then have
      recorded: Immediately, 6 and 12 months after denture use.
    

Intervention name(s): 3d Printed implant; Conventionally constructed implant
Intervention type(s): Device; Device
Intervention description(s): Occlusal stability was evaluated using occlusense device by charting amount and distribution of force over dental arch in percentage; Occlusal stability was evaluated using occlusense device by charting amount and distribution of force over dental arch in percentage
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Treatment