Restorative Treatment of Severe Tooth Wear; Direct vs Indirect


This study compares the survival rates of both direct and indirect resin-based composite restorations in the treatment of severe tooth wear.

Full Title of Study: “A Randomized Controlled Trial On Treatment Of Severe Tooth Wear”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: May 2020

Detailed Description

Tooth wear can lead to pain, discomfort and unsatisfying dental attractiveness and when severe, it can compromise the dentition's prognosis. Restorative therapies for treatment of severe tooth wear should be preferably minimally invasive and adhesive.

This study compares two different treatment techniques for severe tooth wear. The first technique is regarded as the 'standard' technique. This is a full rehabilitation using only direct composite restorations (AP-X, Kuraray, Japan).

The second technique comprises a full rehabilitation using both direct and indirect resin composite restorations (Estenia C&B, Kuraray, Japan). 10 indirect restorations are placed on specific elements i.e. first molars and palatal sides of all maxillary anterior teeth. Other elements are restored conform the direct protocol.

An important benefit for the patients is the rehabilitation of their worn dentitions. Functionality (teeth are less sensitive, improved chewing ability, better occlusal stability, etc) and aesthetics will be improved immediately after finishing the treatment.

Indirect techniques have the advantage of a superior control over form of restorations.


  • Procedure: Rehabilitation of severely worn dentitions using minimally invasive composite restorations (Estenia C&B or Clearfil AP-X, Kuraray, Osaka, Japan)

Arms, Groups and Cohorts

  • Active Comparator: Direct restorative protocol
    • All teeth were reconstructed using non-prep direct hybrid composite restorations (Clearfil AP-X, Kuraray, Japan). Restorations were placed following the DSO-technique (‘Direct Shaping by Occlusion’). Adhesion was acquired using a 3-step etch-and-rinse procedure, including 37% phosphoric acid (DMG, Germany), Clearfil SA Primer and Clearfil Photobond (Kuraray). If a pre-existing composite restoration was present, a repair procedure was performed; The adhesive surface was roughened by a bur, air-abraded ((CoJet (3M) and Danville MicroEtcher CD (Danville Materials, USA)) and a non-hydrolyzed silane coupling agent (Clearfil Porcelain Activator (Kuraray)) was mixed into the adhesive resin. Where needed for esthetical reasons, buccal veneers were made using a nanofilled composite (IPS Empress direct, Ivoclar Vivadent, Lichtenstein). If a buccal veneer was made in a separate session from the palatal direct restoration, then a repair procedure was used.
  • Experimental: Indirect restorative protocol
    • Teeth were restored using a combination of indirect and direct composite restorations. As a result this protocol actually is a hybrid protocol. 10 indirect restorations per patient were made; tabletop restorations on all first molars (n=4) and palatal veneers on maxillary anterior teeth (n=6) using Estenia C&B (Kuraray, Japan). Small retention grooves or pits were prepared and sharp edges on occlusal surfaces were polished using fine-grit burs. Silicone impressions were made for the fabrication of the indirect restorations. Indirect restorations were shaped and cured by a dental technician. Adhesive bonding was acquired using selective etching and ED-primer II (Kuraray, Japan). Before cementation, all indirect restorations were pretreated using phosphoric acid and a silane layer (Clearfil Ceramic Primer, Kuraray, Japan). Panavia F was used for cementation. Subsequently, all remaining teeth were restored with direct composite restorations according to the direct protocol.

Clinical Trial Outcome Measures

Primary Measures

  • Survival level
    • Time Frame: Failures 3 years after placement
    • Number of replaced direct and indirect restorations in the treatment. The higher the number the worse the outcome.
  • Success level
    • Time Frame: Failures 3 years after placement
    • Number of repaired direct and indirect restorations in the treatment. The higher the number the worse the outcome.

Participating in This Clinical Trial

Inclusion Criteria

  • Patients age of at least 18 years old.
  • Generalized moderate to severe tooth wear (Tooth Wear Index (TWI) ≥ 2) with a patient demand for treatment (Smith 1984)
  • Full dental arches, but one diastema due to one missing tooth in the posterior area was allowed.
  • An estimated need for increase of vertical dimension of occlusion (VDO) of ≥3mm at the location of the first molars.

Exclusion Criteria

  • Limited mouth opening (<3.5cm).
  • (History of) Temporomandibular dysfunction, periodontitis, deep caries lesions or multiple endodontic problems.
  • Local or systemic conditions that would contra-indicate dental procedures.

Patients with specific individual risk factors, such as parafunctional habits of grinding/clenching or patients with GORD (Gastro Oesophageal Reflex Disease), were not excluded.

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Radboud University
  • Collaborator
    • Ivoclar Vivadent AG
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Bas Loomans, PhD, DDS, Study Director, Radboud University

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