3D-printed Endocrowns Versus Prefabricated Zirconia Crowns in Pulpally-treated Primary Molars
Condition: Pulpotomy; Tooth Restoration
Study type: Interventional
Phase: Phase 4

Summary: 
      Aim of the study :

      to compare between 3D printed microfilled hybrid composite endocrowns and prefabricated
      zirconia crowns for restoring pulpally treated primary molars regarding the following
      aspects: In Vivo aspects Patient satisfaction

      *The esthetic, functional and biological performance according to FDI clinical criteria. At
      3, 6 and 12 months

      In Vitro aspects:

        -  Marginal gap.

        -  Fracture resistance.

      Study methodology:

      This study is a combined randomized clinical trial and in vitro study .The study will be
      conducted at the Department of Pediatric Dentistry and Dental Public Health, Faculty of
      Dentistry,

      Ain Shams University as follows:

      In vivo comparison of the clinical performance of 3D printed Endocrowns versus prefabricated
      zirconia crowns regarding esthetic, functional and biological performance according to FDI
      clinical criteria. In vitro evaluation of the marginal gap and fracture resistance of both
      types of restorations.
    

Detailed description: 
      Study Procedure:

      In-vivo Phase:

      Study Population:

      A total of thirty primary mandibular molars in healthy subjects will be selected from the
      Pediatric Dentistry and Dental Public Health outpatient clinic, Faculty of Dentistry, Ain
      Shams University. Randomization The molars will be assigned to one of the 2 groups using a
      generated computer list Allocation The molars will be allocated to the groups via a third
      party not involved with the study They will have the generated list and inform the allocation
      accordingly Blinding Is not possible due to the obvious difference between the 2 Pulpotomy
      procedure for both groups:

        1. Local anesthesia will be administered.

        2. Teeth will be isolated by a Rubber Dam.

        3. Teeth will undergo pulpotomy procedure' as follows:

      Caries will be removed using a large size 4 round bur, mounted onto a high speed hand piece
      with constant coolant. All access cavity walls are to be flared to allow complete exposure of
      the pulp chamber, and easy undisturbed access to the canals, followed by removal of all the
      soft pulpal tissue tags by a sharp spoon shaped excavator. Bleeding will be controlled using
      moist cotton pellet with gentle pressure. Formocresol will be applied through a cotton pellet
      for 5 mins, for fixation. The pulp chamber will be filled with reinforced zinc oxide and
      eugenol ( that will be mixed according to manufacturer s instructions. A 0.5 mm layer of
      Resin modified glass ionomer is then applied to the cavity floor and light cured for 40 secs,
      to isolate the zinc oxide eugenol paste, and block unwanted undercuts Analgesics will be
      prescribed to the patient to be taken when needed

      Intervention :group A:

        1. The cavities will be prepared so as to receive endocrowns:

           Occlusal preparation: achieved by drilling, 2mm depth grooves using diamond stone as
           guides for reduction of the occlusal surface. axial preparation: using a 7 degree taper
           diamond stone, eliminating undercuts in the access cavity.

        2. impression for the preparation is taken using putty and light poly vinyl siloxane
           material

        3. Light cured temporary filling will be placed in the cavity as temporisation.

        4. The impression will be sent to the lab and the patient is dismissed

        5. The preparation will be optically scanned in the lab and the restoration will be
           digitally designed using computer designing software.

        6. The restoration will be printed using 3D printer using microfilled hybrid composite
           material.

        7. During the second visit the temporary is removed the restoration is cemented by self
           adhesive resin after etching and bonding the cavity.

      Control Group B:

        1. Crown reduction:

           reduction will be performed on the occlusal surface disregarding the occlusal anatomy
           using a flame stone or a wheel stone, to perform occlusal clearance. Then reduction will
           be performed on the mesial, distal, buccal and lingual surfaces of the tooth to
           compensate for the thickness of the zirconia crowns. Reduction will first be performed
           using fine needle stone to free the contact from the adjacent teeth then followed by
           reduction of the other surfaces using a diamond stone. Roundation of the line angles
           will be performed

        2. Zirconia crowns that match the size of the tooth will be selected putting into
           consideration that no undercuts should be present to avoid crown fracture.

        3. . After checking the size of the crowns, it will be removed, drie d and cemented on the
           tooth using (3M™ ESPE™ KETAC™ CEM) that will be mixed according to manufacturer's
           instructions.

        4. Pressure will be applied on the crown, and any excess cement will be removed after it
           hardens. All children and parents will be give n strict oral hygiene instructions and
           dietary instructions Teeth not included in the study will be scheduled for dental
           treatment in the Department of Pediatric Dentistry, Faculty of Dentistry, Ain Shams
           University. Outcome measurement

      Esthetic functional biological criteria will be evaluated in the following order:

      After cementation evaluation: patients will be evaluated according to FDI criteria as
      previously mentioned,.

      In Vitro phase:

      All soft tissue debris will be removed by a hand scaler and teeth will be disinfect ed, and
      then stored in distilled water at 4 degrees Celsius until the start of the study.

      The molars will undergo pulpotomy procedures and filled as previously described. The molars
      will be randomly divided into two groups Group A: Will receive 3D printed Endocrowns Group B:
      Will receive prefabricated zirconia crowns The specimens will be embedded perpendicularly in
      Polyvinyl chloride ( cubes with the occlusal surface parallel to the ground using acrylic
      resin extending 2mm b elow the cemento enamel junction. The following will be measured:
      Marginal gap Precementation measurements of the cervical vertical marginal discrepancies will
      be performed before cementation. For each specimen, four stereomicrographs will be captured
      by a stereomicroscope (Wild 400, Switzerland) at a 32× magnification. Images will then be
      transferred to the computer software for image analysis

      Fracture Resistance:

      An axial loading condition through the functional cusp will be defined in the mechanical
      failure description. Failure to fracture strength will be tested with a universal testing
      machine at a 0.5 mm/sec crosshead speed. Application of a round end vertical loading tip on
      the occlusal third of a specimen fixed into a loading apparatus as functional loading
      simulation.

      Data Management:

      Patient information will be gathered and stored in the patient examination chart of the
      outpatient clinic, Department of Pediatric Dentistry, faculty of Dentistry, Ain Shams
      University. All information will be kept as a hard copy and as an electronic one as well.
      Patient information will be guarded as co nfidential information that should never be
      revealed at all times. This file will remain with the investigator during the study.

      Statistical Analysis:

      All data will be tabulated, summarized and statistically analyzed using software SPSS
      (Statistical Packages for Social Sciences. 3 and 6 months evaluation: evaluation of the
      previous criteria.
    

Intervention name(s): 3D-printed endocrown; Zirconia crown
Intervention type(s): Procedure; Procedure
Intervention description(s): pulpotomy and restoration with 3D-printed microfilled hybrid composite endocrown; pulpotomy and restoration with prefabricated zirconia crown
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: A total of thirty primary mandibular molars in healthy subjects will be selected.
The molars will be randomly assigned equally into two treatment groups
Group A: 3D printed microfilled hybrid composite Endocrowns
Group B: pr efabricated zirconia crowns Pulpotomy
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: 3D-printing; Endocrown; zirconia crown