Can Zirconia Crown be the First Choice for Primary Teeth?
Condition: Dental Caries in Children
MeSH terms: Dental Caries
Study type: Interventional

Summary: 
      Objective: Early loss of primary teeth due to caries, can cause occlusion disorders,
      aesthetic problems, nutritional problems, abnormal language habits, speech disorders and
      psychological problems temporary or permanent. The purpose of this study was to evaluate the
      success of using prefabricated aesthetic crowns for the restoration of excessive tooth loss.

      Study design: In this randomized, non-blinded clinical study a total of 45 teeth were
      included, primary molars and anterior teeth and requiring restoration after root canal
      treatment. Stainless steel(SCC), zirconia(ZC) and strip(S) crowns compared clinically,
      radiographically and periodontally during follow up period for 6 months. Parents were asked
      to fill out questionnaire at the 1st and 6th months to evaluate the satisfaction level. In
      addition, patients' pain and discomfort level was assessed using the visual analogue scale
      (VAS) scale.
    

Detailed description: 
      The color of crowns made it impossible to blind during clinical assessment. Thus, this study
      was a non-blinded, randomised, and prospective clinical trial.

      Sample size: This study included 20 maxillary anterior and 25 posterior teeth that required
      restoration due to excessive material loss. The study groups were:

      Zirconia crown(ZC) restoration on the primary central and lateral tooth with root canal
      treatment (n = 10), strip crown(S) restoration on the primary central and lateral tooth with
      root canal treatment (n = 10), Zirconia crown(ZC) restoration on primary teeth with root
      canal treatment (n = 12), Stainless-steel crown(SSC) restoration on primary teeth with root
      canal treatment (n = 13).

      Clinical Procedure:

      Assessment

      Clinical assesment: Table 1 Gingival scores: Löe and Silness Gingival Index(GI)[Löe, 1967].

      Periapical radiographic evaluation: Preoperative and every follow up visit. (Radiographic
      assesment: Table 2)

      Intraoral photos (standard method): before treatment, after treatment and at every follow-up
      visit.

      Crown restoration: All caries were removed after administration of local anaesthesia and
      proper isolation. Calcium hydroxide/iodoform paste (Vitapex®) pulpectomy was performed
      according to the guideline. Teeth were restored with a composite resin Nova Resin (IMICRYL®,
      Konya, Turkey) and glass ionomer cement (MERON®, Voco, Germany) was used as a base material.
      Strip Crown Forms (3M-ESPE, St. Paul,Minnesota, USA) were used to restore teeth group SC. ZC
      group (NuSmile, Houston, Tex. the USA) and SCC(3M ESPE, Minnesota, USA) used.

      Visual analogue scale(VAS): 0-2: no pain/discomfort 4-6:moderate 8-10: high pain/discomfort.

      The child was asked to choose his/her feelings about the tooth after the procedure and in
      follow-up appointments. Parents were asked to complete their satisfaction surveys, including
      the post-op and 6-month controls for patient satisfaction assessment.

      Statistical Method:

      IBM® SPSS® Statistics V23 analysed data. The Mann-Whitney U and Chi-square tests were used
      for intergroup comparisons within the anterior and posterior regions. The Friedman and
      Cochrane Q tests were used for intra-group time-wise comparisons. Analysis results were
      presented as the median (q1-q3) and frequency (percentage). P<0.05 was considered
      statistically significant.

      Table 1: Clinical assesment

      Crown retention 0= yes 1= no

      Individual modified gingival index 0= healthy 1= mild gingival bleeding with a papillus 2=
      severe inflammation

      Plaque index 0= no plaque

        1. = presence of plaque as a film in the gingival margin

        2. = presence of moderate plaque

        3. = plaque covering a large number of surfaces

      Color change 0 = no coloring

        1. = minor coloration

        2. = noticeable coloration

      Buccal strip crown surface 0 = no loss 1 = less than 50% loss 2 = more than 50% loss 4 = loss
      of the entire surface

      Surface abrasion of the antagonist teeth 0= no abrasion

        1. abrasion started on the incisal surface of the casps

        2. abrasion more than on the casps

      Position of the crowns regarding gingival margin 0= subgingival

      1= supragingival

      Occlusion 0= contact (marked or superficial) 1= no contact

      Condition of the antagonistic tooth 0= natural tooth

        1. restored tooth

        2. stainless steel crown

        3. aesthetic crowns

      Location on the arch curve 0= normal alignment

        1. with rotation

        2. wrong position

      Proximal contacts 0= good (floss passing)

      1= weak, no contact

      Table 2. Postoperative Radiographic Evaluation Criteria and Scores Radiographic evaluation of
      crown margins 0=good adaptation, continuity in crown contractions

        1. small radiolucent area under the restoration

        2. huge openings

        3. loss of restoration

      Radiographic evaluation 0= healthy, no pathology

        1. presence of a pathology that does not require immediate treatment

        2. presence of pathology requiring immediate treatment

      Radiographic evaluation of pulpal treatment 0=appropriate root treatment

        1. short or overflowed root treatment

        2. failed pulpal treatment

        3. tooth with no pulpal treatment
    

Intervention name(s): Dental Crown
Intervention type(s): Other
Intervention description(s): Pediatric size dental crown; restore damaged tooth to its normal shape, size, and function.
Other intervention name(s): Zirconia Crown (NuSmile, Houston, Texas, USA); Stainless Steel Crown (3M-ESPE, St. Paul, Minnesota, USA); Strip Crown (3M-ESPE, St. Paul, Minnesota, USA)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: zirconia; crown; endodontic; pediatric