Evaluation of Stress Distribution and Displacement in the Affected Periodontium of Mandibular Incisors Using Utility Intrusion and Reverse Curve of Spee Arch Wires: A Finite Element Analysis

TL;DR

This study uses computer modeling to compare two orthodontic wires in managing stress and tooth movement in cases of bone loss around lower front teeth.

Contribution

The study introduces a finite element analysis comparing utility intrusion and reverse curve of Spee arch wires in varying levels of bone loss.

Findings

Higher bone loss increases stress and decreases displacement, leading to labial tipping.

Utility intrusion arch wire shows better torque control and less labial tipping than the reverse curve of Spee wire.

Stress distribution is consistently higher with the utility intrusion arch wire across all bone loss levels.

Abstract

Objective: This study aims to evaluate stress distribution and displacement in the affected periodontium of mandibular incisors with utility intrusion arch wire and reverse curve of Spee (RCS) arch wire using finite element analysis (FEA).

Materials and methods: A 3D finite element model (FEM) of the mandibular arch was created, simulating mandibular incisors with three variations of bone loss (0%, 33%, and 66%) and 0.022” x 0.028” slot MacLaughlin, Bennett, and Trevisi prescription brackets. Utility intrusion arch wire and RCS arch wire were modelled using 0.017” x 0.025 stainless steel and subjected to activation. Stress distribution and displacement were calculated and analyzed.

Results: Comparison between utility intrusion arch wire and RCS arch wire, using FEM for mandibular incisors with varying bone loss (0%, 33%, and 66%), revealed alteration in the stress distribution and displacement patterns. Increasing bone loss at mandibular incisors raised stress distribution while reducing displacement, suggesting labial tipping. The utility intrusion arch wire exhibited higher stress distribution than the RCS arch wire at all bone loss levels. The RCS arch wire caused labial tipping of the mandibular central incisors. In contrast, the utility intrusion arch wire minimized displacement across all mandibular incisors in FEMs despite variations in bone loss. The utility intrusion arch wire displayed better torque control, reducing labial tipping compared to the RCS arch wire, irrespective of bone loss levels.

Conclusions: Elevated bone loss in mandibular incisors resulted in increased stress distribution and decreased displacement, implying a tendency toward labial tipping. The utility intrusion arch wire consistently exhibited higher stress distribution but minimized displacement compared to the RCS arch wire, highlighting its potential for better torque control and reduced labial tipping, particularly with the progression of horizontal bone loss.

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