Single and two phase early treatment

Recent research confirms what clinical experience has suggested: Single phase treatment with LM-Activator in the early mixed dentition gives amazing results that remain stable into adulthood.

Treatment is typically started when the first permanent upper incisor begins to erupt. When the signs of malocclusion are detected early, interferences can be intercepted and malocclusions can be corrected before they become more severe. Further development of a malocclusion can be avoided.

In Single Phase Early Treatment, retention follows immediately after active treatment. This is a notable difference to Two Phase Early Treatment that typically has a pause phase, which may cause relapse, between the first and second treatment phases.

By intervening early when roots and ligaments are still developing, a more gentle orthodontic treatment with smaller forces is possible. More complex treatment applying more force may be avoided.

 “Long term results showed that the results of the early treatment are stable in the permanent dentition at the age of 17 years. With early treatment, you will have good short term results after active treatment in the early mixed dentition and stable long term results in the permanent dentition.”
– Professor Juha Varrela, University of Turku

In some cases, treatment with LM-Activator is also possible during the late mixed dentition or early permanent dentition.

LM-ActivatorStart treatment with LM-Activator

Age 5: Fully developed deciduous dentition with deep bite. Start of treatment with LM-Activator.


Age 8: End of active treatment


Age 18: Results remain stable.

Pictures: Keski-Nisula, K. 2008: Occlusal and dentofacial characteristics of the deciduous dentition and treatment effects of the eruption guidance appliance in the early mixed dentition. Annales Universitatis Turkuensis D 827, 92 Varrela J. Effectiveness of the eruption guidance in early orthodontic treatment. World Federation of Orthodontists 7th International Orthodontic Congress, Feb 6.-9. 2010, Sydney, Australia.

Treatment with LM-Activator is cost effective as it allows shorter chair time and reduces treatment complexity and emergency visits.  Treatment can be started without delay and no adjustments are required during treatment.

Treatment protocol

LM-Activator is worn every night while sleeping. The teeth should be kept tightly in the appliance with lips closed. If treatment is started after eruption of the permanent upper centrals, two hours of day-wear is recommended in addition to night-wear. Day-wear is continued until the malocclusion is corrected.

Co-operation and motivation

Patient compliance is essential for successful treatment. The first month is crucial in adopting the habit to use. To motivate the patient and parents age appropriate materials are available.

Two phase early treatment

Two-phase orthodontic treatment consists of two separate periods of orthodontic treatment [VV]:

  • A first phase during the mixed dentition.
  • Second phase when the child has most or all of their permanent teeth.

According to the AAO, potential benefits of early treatment are [WW]:

  • Preventing or intercepting more serious problems from developing.
  • Making the second phase shorter and less complicated.
  • Achieving treatment results that may not be possible without taking advantage of natural growth of the mandible.

LM-Activator can be used both in the first phase as an active appliance as well as between the first and second phases as a retainer, which permits natural dentofacial development.

According to a Cochrane meta-analysis based on three RCT studies, one phase treatment and two phase treatment seem to give very similar final results [Harrison]. Meta-analyses and RCTs have well-known limitations [Rawlins, Fisher, King, Strobe, Schroll, Cochrane] and their results and conclusions cannot be generalized beyond the study context [Rawlins]. The above mentioned RCTs are based on a two phase protocol with the possibility of a pause phase in between. Recent research results indicate that growth modification should occur during the juvenile growth spurt and/or the pubertal growth spurt [Keski-Nisula 2008 A, Keski-Nisula 2008 B, Varrela, Baccetti 1997, Baccetti 2009]. In severe cases, it may be beneficial to activate growth during both spurts.

Reference list

Juvenile growth spurt 

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