Success Rates of Hall Technique Crowns in Primary Molars: A Retrospective Pilot Study

Objectives: The purpose of this retrospective observational study was to assess success rates, both clinical and radiographic, of stainless steel crowns placed on primary molars using the Hall technique at the University of Iowa College of Dentistry. The results of this study will help to determine future research avenues for the study of "Hall crowns".
Methods: A retrospective analysis was performed using recorded data of patients with any primary molar treated with a stainless steel crown (SSC) placed by the Hall technique between 2008-2015 at the University of Iowa College of Dentistry. The primary outcome of failed treatment was categorized in two different ways: clinical and radiographic failure. Clinical failure was defined as the need for pulp therapy or extraction following initial crown placement. Radiographic failure was defined by the presence of any pathologic condition including: external/internal resorption, bifurcation radiolucency or widened PDL resulting from treatment.
Results: Of the 293 crowns (mean age of child=5.1±2.4 years, 61.1% male) that fulfilled the inclusion criteria, 180 crowns returned for at least one follow up (mean time=9.9 months). At the first follow up, 178 (98.9%) of 180 SSCs placed using the Hall technique were clinically successful and of those with radiographs available 86 (98.9%) of 87 were radiographically successful. After the second follow up visit (mean time=20.1 months) 74 (97.4%) of 76 were clinically successful and 37 (94.9%) of 39 were radiographically successful.
Conclusions: These preliminary results provide significant information regarding the outcomes of primary molars treated with Hall technique crowns and validate prospective investigation with greater specificity and extended follow-up in the future. Further analysis is ongoing and results will be reported.