Beyond Wires and Brackets: A Modern Tooth Movement

Lori R. Trost, DMD


January 04, 2012

Minor Tooth Movement: Overview

One of the most versatile techniques in dentistry today is the application of Minor Tooth Movement (MTM®). This treatment option comprises movement of teeth using plastic aligners and thermopliers (Dentsply Raintree Essix®, Dentsply, Sarasota, Florida) and produces outstanding aesthetics and function. This method is a minimally invasive approach to patient care.

Technically speaking, MTM involves the movement of 1-4 teeth per arch using continuous, gentle force. Traditional orthodontic movements, consisting of rotation, tipping, and lateral position change, can be achieved by the patient wearing an in-office fabricated aligner. At each return patient visit, gentle pressure is applied to the aligner, using thermopliers that are designed to create intentional, guided force of up to 1 mm per month, resulting in correct alignment. Most cases treated by this method are completed in 6 months or less.

Case Selection for MTM

Case selection is paramount to meet the parameters of MTM. MTM can be used to treat easy orthodontic cases, refine previous alignments, and set the stage for restorative and esthetic cases that may involve composite bonding, crowns, veneers, or implants. Any patient under consideration for MTM should have permanent dentition, present with a healthy periodontal state, have no temporomandibular joint symptoms, and demonstrate adequate arch length. Criteria that warn practitioners of poor case selection are severe incisor rotation, xerostomia, active caries, and a non-compliant patient.

A key component in many minor tooth movement cases is the available arch space in which to re-align the teeth. Length discrepancies must be considered for a successful treatment outcome. Arch presentations that exceed 2 mm in length discrepancy are not considered within the guiding principles of MTM case selection, and are not acceptable cases for this method of treatment. Dentists must make sure to accurately measure the widest dimension of each tooth, from canine to canine. Each of these widths are then added together to arrive at the total width for the teeth present within the arch. This measurement is compared to the measurement of the existing arch from the distal to distal of each canine. The difference of these 2 values -- given arch length and total teeth width value --translates to the amount of space required to complete alignment.


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