RESUMEN
PURPOSE: Hall technique (HT) preformed metal crowns (PMCs) are allegedly oversized compared to conventional (C) PMCs. To investigate paediatric dentists' (PDs) perception of HT-PMCs and perception/ability to identify HT or C-PMCs on bitewings radiographs. METHODS: An online cross-sectional questionnaire including ten bitewings (five of each of HT/CPMCs) was sent to PDs across the globe. A PMC type score (from '10') was calculated. T test, Pearson's and Fischer's Chi-square, and Odd Ratios (OR) (p < 0.05). RESULTS: A total of 476 PDs from around the world responded. Most (97%) used PMCs in their practice. Most (98.7%) knew of, and 79% used HT-PMCs. A clear opinion shift, towards supporting HT, over time was noted (OR 11.154 [95% confidence interval (CI) 6.006-20.715]. A majority (67%) thought that HT/C-PMCs were similar radiographically. Only five PMCs were identified correctly [mean score 4.9 (± 1.73)]. A minority who thought that HT/C-PMCs were dissimilar scored higher than those who thought they were similar (5.31 ± 1.22; 4.68 ± 1.9, respectively, p < 0.00001). Nobody identified all ten PMCs. HT-PMCs were 4.63 times more identifiable than C-PMCs [(OR 24.857 CI 15.059-41.028) and (OR 5.361 CI 3.089-9.304)] for HT-PMCs and CP-MCs, respectively (p < 0.0001). CONCLUSIONS: PDs identified the PMC type in half of the bitewings. They perceived no clear radiographic difference between HT-PMCs and C-PMCs, but their chance of recognizing HT-PMCs was five times higher than C-PMCs. HT-PMC support was high.