Do Hall Technique Crowns Affect Intra-arch Dimensions? A Split-mouth Quasi-experimental Non-randomized Feasibility Pilot Study.

Aim and background: The Hall technique preformed metal crowns (HT-PMCs) are allegedly oversized, temporarily altering inter-arch relationships. Intra-arch dimensions and leeway space (LWS) HT effects are unknown.

Aim: To study single HT-PMC intra-arch effects and treated tooth dimensional changes.

Materials and methods: Split-mouth, quasi-experimental, non-randomized feasibility pilot study. Intraoral scans (iTero II®) were taken preorthodontic separator placement (scan¹), immediately post single HT-PMCs (scan²) in 13 children, and 1 month later (scan³) in eight children. Control and study quadrants' lengths ("arcs") and HT-PMCs/control tooth dimensions [mesiodistal (MD), buccopalatal/lingual (BP/L), diagonal (Diag1/Diag2)] were recorded in mm (OrthoCAD® software). Paired t-test, repeated analysis of variance (ANOVA) post hoc analysis statistics (p < 0.05).

Results: Compared to scan¹, the mean study arc increased by 0.7 mm (±0.5) (n = 13, t-test, p < 0.001) at scan², while at scan³, it increased by 0.8 mm (±0.34) (n = 8, repeated ANOVA, p = 0.008). The HT-PMCs-treated tooth mean dimensions increased at scan² by 0.9 mm (MD), 0.8 mm (BP/L), 0.5 mm (Diag1), and 0.7 mm (Diag2) (t-test, p < 0.001) with similar observations at scan³. There were no significant changes in the control arc or the control tooth measurements.

Conclusion: One single HT-PMC increased the intra-arch quadrant length by approximately up to <1 mm. The HT-PMC-treated tooth was marginally oversized. This pilot study paves the way for a more robust study with a larger sample size.

How to cite this article: AlRamzi B, AlHalabi M, Kowash M, et al. Do Hall Technique Crowns Affect Intra-arch Dimensions? A Split-mouth Quasi-experimental Non-randomized Feasibility Pilot Study. Int J Clin Pediatr Dent 2024;17(6):673-682.