Survival of Hybrid Laminate Veneers Using Two Different Tooth Preparation Techniques:Randomized Clinical Trial
Condition: Discoloration, Tooth; Malformed Tooth; Diastema
MeSH terms: Tooth Discoloration; Diastema
Study type: Interventional

Summary: 
      The aim of this study was to evaluate the survival of laminate veneers constructed using a
      recent polymer-infiltrated ceramic network material following the aesthetic pre-evaluative
      temporary (APT) technique of tooth preparation in comparison to traditional technique.
    

Detailed description: 
      Six recruited patients (4 females, 2 males; ranging from: 20-30 years old and with mean age
      24.6 years), who needed indirect laminate veneer restorations were included in this study.
      Patients were selected from the outpatient clinic of the Department of Fixed
      Prosthodontics,Faculty of Dentistry, Cairo University The participants received a total of 54
      laminate veneers between April 2017 and February 2018. Written informed consent was acquired
      from all participating patients. Randomization was done using a computer generated 2 column
      list by the aid of Random.org in a 1:1 ratio. Allocation concealment was achieved using
      numbered cards in opaque sealed envelopes. Aluminium foil was placed inside the envelope to
      render the envelope impermeable to intense light. These envelopes were placed in a box and
      each participant was allowed to grasp one envelop the day of operation. Allocation
      concealment was performed by an investigator with no clinical involvement in the trial. This
      study is a single blinded study as the assessor was blinded to the assigned study groups.
      Blinding of the participants was not applicable as one of the techniques required extra
      visits. Blinding of the operator was not applicable as one clinician performed the tooth
      preparation in both techniques.A total of 54 laminate veneers were divided into two equal
      groups (n=27) according to the technique of tooth preparation: group T: traditional technique
      and group A: aesthetic pre-evaluative temporary technique. VITA ENAMIC material was used for
      CAD/CAM construction of laminate veneers. Cementation was performed using a light cured resin
      cement. The laminate veneers were evaluated at baseline, after 3, 6 and 12 months according
      to the modified United States Public Health Service (USPHS) criteriea. The data was
      collected, tabulated and statistically analyzed.
    

Intervention name(s): traditional technique of tooth preparation; aesthetic preevaluative temporary technique for tooth preparation
Intervention type(s): Procedure; Procedure
Intervention description(s): Depth cutter wheels of predetermined depths (Komet, Germany) were used to perform the preparation directly on the tooth structure.
Depth cuts were performed on the labial surface using depth cutter wheels (Komet, Germany) with radius of 0.3 mm and 0.5 mm which is directly related to the thickness of the laminate veneers in the cervical and incisal one thirds respectively. Then islands of tooth structure between depth orientation grooves were removed.
Proximal reduction:
The interproximal reduction was completed just labial to the contact areas using a round end tapered diamond stone (Mani, Japan), and polishing was performed using polishing strips (Sof-Lex, 3M ESPE, Seefeld, Germany).
Incisal reduction:
Vertical depth grooves were created. Then, the round end tapered diamond stone (Mani, Japan)was used to create 1.5 mm incisal butt joint preparation.
Then, finishing and polishing of tooth preparation was performed.; The data obtained from digital smile design was used for construction of the diagnostic wax-up. The wax-up was then be transferred to the mouth using a silicone index, creating the aesthetic pre-evaluative temporary (APT). The APT was tested esthetically and functionally. Once approved by the operator and the patient, tooth preparation was performed through the APT. Depth cuts were performed similar to those performed in the traditional preparation with the difference of being prepared on the aesthetic pre-evaluative temporary instead of directly on the dental structure. Using tapered stone with round end (Mani, Japan), islands of tooth structure between depth orientation grooves were removed.
Proximal reduction, Incisal reduction Finishing and polishing of tooth preparation were carried out using the same technique as in the Group T with the difference of being performed through the APT, resulting in minimal tooth preparation
Other intervention name(s): Group T; Group A
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: veneers; hybrid ceramics; CAD/CAM; tooth preparation techniques; USPHS criteria