A randomised controlled trial comparing clinical performance and survival of artisanal versus computer assisted design computer assisted manufactured zirconium silicate filled composite endocrowns / Noor Aaina Zainon

Introduction: Endocrown has been proven as an advantageous option for rehabilitation of endodontically treated molar tooth with extensive cuspal loss mostly using ceramic based materials. A double-blinded (patients and examiners) and equally randomized parallel groups, non-inferiority trial was carried out to assess the clinical performance and survival of artisanal versus computer assisted design-computer assisted manufactured (CAD-CAM) zirconium silicate filled-composite endocrowns after 18 months. Methodology: 28 patients (mean age: 42.14 years old) randomly received endocrowns constructed by a single operator from two commercially available zirconium silicate filled-composite material (Artisanal: CERAMAGE Shofu (n=14) and CAD-CAM: SHOFU Block HC (n=14)) according to the inclusion and exclusion criteria. The endocrown restorations were evaluated by three calibrated examiners at 1- week post-insertion (baseline), 1, 6, 12 and 18 months using the modified USPHS criteria. The primary outcomes are success and survival; the secondary outcomes are prognostic factors and complications. Survival of the endocrowns was analysed using Kaplan-Meier survival curves, the log-rank test, and the Cox proportional hazards regression analysis. Results: Survival rates of artisanal and CAD-CAM zirconium silicate filled composite endocrowns were 85.7% (95% CI: 53.9, 96.2, P>0.05) and 72.5% (95% CI: 33.7, 90.9 P>0.05) while the success rates were 61.2% (95% CI: 24.6, 84.2, P>0.05) and 72.5% (95% CI: 33.7, 90.9, P>0.05) respectively. The Fisher’s exact test showed no significant difference between the clinical performance of artisanal and CAD-CAM zirconium silicate endocrowns during the short-term evaluation period (P>0.05). Prognostic factors such as patient demographics (age, gender and ethnicity) and clinical factors (arch of prosthesis, depth of pulp chamber, crown lengthening procedure and methods of endocrown fabrication) were not significantly associated with the clinical performance of both artisanal and CAD-CAM zirconium silicate endocrowns (P>0.05). Seven endocrowns failure were observed in the form of technical and biological complications such as mild chipping (n =1), debonding (n = 1), bulk fracture or severe chipping (n = 4) and endodontic complication (n =1) following 6- months evaluation period. No abutment or root fractures was seen during the observation period. Conclusion: Although, zirconium silicate filled composite endocrowns appear to be a convenient and safe technique to restore the extensively damaged endodontically treated molar teeth, their selection should be based on proper case selection and informed consent from the patient due to the low success and survival rate based on short-term observation.