121 - Prefabricated Zirconia Crown Survival Rates Without Direct Pulp Therapy

Abstract: Prefabricated Zirconia Crown Survival Rates Without Direct Pulp Therapy

Purpose: This study aimed to evaluate the success rate of pediatric anterior prefabricated zirconia crowns placed without prophylactic and direct pulpal treatment in primary teeth. This question is clinically relevant given recent emphasis from AAPD on prioritizing indirect pulp therapy, contrasted with the widespread belief that the aggressive tooth preparation required for zirconia crowns necessitates routine pulpotomy or pulpectomy regardless of original pulpal status.

Methods: A retrospective chart review was conducted using the electronic medical record of the Primary Children’s Hospital dental residency program. Patients who received anterior prefabricated zirconia crowns on primary teeth without concurrent pulpotomy or pulpectomy within the past three years and who returned for subsequent follow-up visits were included. Pulpal failure was defined by clinical or radiographic evidence of necrosis, pulpitis, abscess, pain, or pathologic resorption. Non-pulpal failures, including crown debonding or fracture, were recorded but excluded from primary outcome analysis. Survival analysis was performed using the Kaplan–Meier method to estimate crown survival over time. Time-to-event was defined as the interval, in months, from crown placement to documented failure. Crowns without failure were treated as censored observations at the time of the last recorded follow-up visit.

Results: 142 patients received pediatric anterior prefabricated zirconia crowns without direct pulpal treatment, with a total of 394 crowns treated. Of the 394 crowns, 232 were examined at follow up appointments. Of the 232, 12 experienced pulpal failures (5.1%). Among these 12 pulpal failures were: 2 failures in which the crowns were never properly seated and 1 failure in which the crown was lost but did not abscess for nearly 16 months. Even so, the Kaplan Meier Survival Analysis showed that over 80% of the crowns remained successful at 55 months and that resorption failures may occur faster than abscess failures. There were not enough failures to reliably test the significance between abscess and resorption survival functions. Interestingly, multiple crowns debonded without their respective teeth experiencing pulpal failures, including both teeth that received new crowns and teeth that did not.​

Conclusions: Despite significant tooth structure removal required for preparing pediatric anterior prefabricated crowns, prophylactic pulpal therapy may not be indicatedWhen primary anterior teeth have normal pulps or reversible pulpitis, prefabricated anterior zirconia crowns can be provided without direct, prophylactic pulpal treatments and experience high success rates up to 55 months. This is despite the significant reduction in tooth structure required for such crowns' preparation. This finding allows pediatric dentists and residents to take a more conservative approach to such restorations, simultaneously lowering patient costs, maintaining the vitality of the primary tooth, shortening procedure (and often general anesthesia) times, and avoiding the failure risks involved in providing additional procedures.

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