Can Zirconia Crown be the First Choice for Primary Teeth?

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

• = presence of plaque as a film in the gingival margin
• = presence of moderate plaque
• = plaque covering a large number of surfaces

Color change 0 = no coloring

• = minor coloration
• = 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

• abrasion started on the incisal surface of the casps
• 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

• restored tooth
• stainless steel crown
• aesthetic crowns

Location on the arch curve 0= normal alignment

• with rotation
• 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

• small radiolucent area under the restoration
• huge openings
• loss of restoration

Radiographic evaluation 0= healthy, no pathology

• presence of a pathology that does not require immediate treatment
• presence of pathology requiring immediate treatment

Radiographic evaluation of pulpal treatment 0=appropriate root treatment

• short or overflowed root treatment
• failed pulpal treatment
• tooth with no pulpal treatment

Inclusion criteria

• Patients without systemic disease The American Society of Anesthesiologists (ASA)1-2,
• Patients under 10 years old to perform endodontic treatment for adequate root support
• Clinical and radiographically confirmed dental caries scored international caries detection and assessment system(icdas) criteria 4-5.
• Patient/parent approve

Exclusion criteria

• Patients with systemic and mental diseases
• Acute abscess or mobility
• Internal or external resorption
• Inadequate oral hygiene after oral health motivation that contraindicate root canal treatment
• Need for endocarditis prophylaxis
• Temporomandibular joint(TMJ) disorders, bruxism
• Absence of antagonistic teeth