Increased tooth mobility after fixed orthodontic appliance treatment can be selectively utilized for case refinement via positioner therapy - a pilot study

L Keilig,N Daratsianos,C Dirk,C Bourauel,A Konermann,A Jäger,J Goedecke

doi:10.1186/s12903-020-01097-4

Abstract

BackgroundIncreased tooth mobility persists after fixed orthodontic appliance removal, which is therapeutically utilized for post-treatment finishing with positioners. As such a fine adjustment is only required for selected teeth, the aim of this pilot study was to investigate tooth mobility in vivo on corrected and uncorrected subgroups under positioner therapy.MethodsMobility was measured on upper teeth of 10 patients (mean age 16.8) by applying loadings for 0.1, 1.0 and 10.0 s with a novel device directly after multibracket appliance debonding as much as 2d, 1, 2 and 6 weeks later. Positioners were inserted at day 2. Specimens were divided into Group C (teeth corrected via positioner), Group N (uncorrected teeth adjacent to teeth from group C), and Group U (uncorrected teeth in an anchorage block). Untreated individuals served as controls (n = 10, mean age 22.4). Statistics were performed via Kolmogorov-Smirnov test and Welch’s unequal variances t-test for comparisons between groups. P < 0.05 was considered statistically significant.ResultsAfter 1 week, tooth mobility in Group U almost resembled controls (13.0–15.7 N), and reached physiological values after 6 weeks (17.4 N vs. 17.3 N in controls). Group C (9.0–13.4 N) and Group N (9.2–14.7 N) maintained increased mobility after 6 weeks. Tooth mobility was generally higher by reason of long loading durations (10.0 s).ConclusionsPositioner therapy can selectively utilized increased tooth mobility upon orthodontic fixed appliance treatment for case refinements. Here, uncorrected teeth in anchorage blocks are not entailed by unwanted side effects and recover after 6 weeks post treatment. Corrected teeth and their neighbors exhibit enhanced mobility even after 6 weeks, which represents a necessity for the proper correction of tooth position, and concurrently arouses the requirement for an adequate retention protocol.

Highlights

Increased tooth mobility persists after fixed orthodontic appliance removal, which is therapeutically utilized for post-treatment finishing with positioners
As only some teeth need fine corrections after fixed appliance treatment, it can be assumed that corrected and uncorrected teeth differ in the timing for restoration of the periodontal ligament (PDL) and surrounding tissues as much as for the retrieval of physiological posttreatment tooth mobility (TM)
In this pilot study, TM was analyzed on upper teeth during positioner therapy for case refinement of selected multibracket cases, and compared to physiological values of untreated control teeth

Summary

Introduction

Increased tooth mobility persists after fixed orthodontic appliance removal, which is therapeutically utilized for post-treatment finishing with positioners As such a fine adjustment is only required for selected teeth, the aim of this pilot study was to investigate tooth mobility in vivo on corrected and uncorrected subgroups under positioner therapy. As only some teeth need fine corrections after fixed appliance treatment, it can be assumed that corrected and uncorrected teeth differ in the timing for restoration of the PDL and surrounding tissues as much as for the retrieval of physiological posttreatment tooth mobility (TM) This issue is a matter of debate that needs further investigation, even though the biomechanical properties of PDL tissues and TM have been approached in numerous in vitro and in vivo studies [1, 6,7,8,9,10,11,12,13]. Fast loadings lead to minor tooth displacements compared to slow loadings, as fluid exchange requires a longer time span [14]

Methods

Results

Discussion

Conclusion