Many types of early treatment are labeled “Phase I” or may also be presented as a “Limited Treatment.” The purpose of a Phase I treatment plan or a limited treatment plan is to provide a problem focused treatment that is limited in scope and duration. This approach to treatment has many benefits, and is a somewhat recent addition to orthodontic treatment philosophy.
For several reasons, historically orthodontic treatment was postponed until all of the baby teeth were lost, the permanent teeth were all fully erupted, and most of growth was complete. This meant that treatment would not usually start until the patient was about 12-15 years old and may continue through highschool. For decades, the average treatment time in the United States and Canada was over 3 years. Thankfully, due to some wonderful technological advancements, the average treatment time has reduced significantly, treatment is more comfortable, and the forces used to move the teeth are more physiologically compatible.
The old-time philosophy was a “wait until things are as bad as they can get, then we’ll go in and fix it!” Some would consider this to be supervised neglect, but that was the best that could be done at the time, as we did not really understand growth modification or have appliances that were effective. Growth modification and the appropriate appliances were being developed in Europe, but did not make it to the US until the 1970’s. Many of the early appliances were very effective, but required significant wear time and they were bulky and somewhat awkward. The appliances improved and were easier to wear, but there was a steep learning curve for the doctors, and the results of the growth modification are not completely predictable.
For growth modification to be effective, there needs to be growth taking place to modify. This type of treatment must be started early and take place for an extended time while growth is occurring. With the treatment starting early for growth and the braces not starting until later, this presents some logistical and practical concerns. No one wants to be in continuous active treatment for half a decade. To resolve this, a Phase I/Phase II approach to treatment was adopted. In this approach to treatment, the treatment is started early to take advantage of growth and development. This early phase of treatment terminates when the objectives have been met, and the patient enters an inter-phase or “vacation” period prior to starting Phase II treatment. Phase II normally starts when the full adult dentition is erupted.
In the above illustration, Phase I is the growth modification phase and a functional appliance would be used to correct any skeletal discrepancies. There are many types of skeletal discrepancies, and many differing appliances to address the individual problems encountered. Sometimes an expander appliance is all that is needed. Other times the problems are 3- dimensional and require more complicated appliances and more time and effort to achieve successful skeletal change. If no skeletal discrepancies exist and growth modification is unnecessary, early treatment to address dental complications like crowding or impacted canine teeth is desirable and necessary to avoid more severe problems later on. Phase I treatment may be very complicated and involve growth modification and skeletal corrections in addition to altering the eruption pattern of teeth and resolving the crowding or other dental issues. Or Phase I may be very limited and focused on correcting only a single tooth that is in cross-bite.
Phase I can be considered the early orthopaedic growth modification stage (if a comprehensive Phase I treatment plan is pursued). Phase II is the orthodontic phase of treatment that is done after all the permanent teeth are present and the goal is to align all the teeth and create that “Hollywood Smile.” A comprehensive Phase I aligns the jaws, coordinates the arches, and prepares the mouth to accept all the permanent teeth. The goal is to arrive at Phase II with a normal jaw relationship, normal overlap and overbite in the front teeth, and a normal bite relationship with mild crowding that will be corrected with braces or aligners. This is the goal in comprehensive Phase I treatment, but as is often encountered in life, neither the orthodontist nor the patient/parent have control of all the factors and Mother Nature may not do what is expected and things don’t develop as desired. Occasionally, growth modification and other aspects of treatment are not as successful as planned. This is always disappointing for everyone, but comfort can be found in the fact that things are always better than they would have been if a traditional “wait until things are as bad as they can get, then we’ll go in and fix it!” approach to treatment.
Phase I may be extremely complicated or extremely limited. If Phase I treatment is comprehensive and addressing multiple complicated skeletal and dental issues, it will take a substantial amount of effort and an investment of time and resources. If a Limited Phase I consists only of aligning the four front teeth, the cost and time invested should be minimal and the results only a cosmetic benefit that has little impact on future treatment needs. Because of this, any cost comparison of Phase I treatment in one office opposed to another office is very difficult. The treatment objectives in an office where the doctor does not buy into a comprehensive Phase I philosophy may be very limited when compared to another doctor who is more focused on working with “Mother Nature” and growth and development and presents a treatment plan where the objectives are comprehensive. The Phase I name may be the same, but they are completely different animals. You’re not even comparing apples to oranges, it’s more like apples to kumquats.
If Phase I treatment is limited, it can be started any time during the mixed dentition period (the time when there is a mix of adult and baby teeth), provided there is time to achieve the limited objectives of the treatment before the patient is ready to start a comprehensive treatment. Depending on the circumstances, this doctor prefers to allow the patient at least a year of vacation time between Phase I and Phase II. There should always be an clean ending to Phase I and a clear start to Phase II treatment. Going directly from Phase I into Phase II should be an extremely rare occurrence. In comprehensive complicated Phase I treatment it is critical that the patient be seen early and treatment begin at a young age if there is to be a desirable interphase rest/vacation period.
In a properly designed comprehensive Phase I treatment plan, there are 3 major objectives. The skeletal discrepancies should be corrected as appropriate growth modification is instituted, the dental arches should be developed and space created for the eruption of all permanent teeth, and the overbite and overlap of the front teeth should be normalized. Provision for each of these treatment objectives is made in the plan and are executed during the active part of Phase I treatment or during the inter-phase vacation period. If these 3 objectives are met, and all the permanent teeth erupt in a normal fashion, Phase II treatment should be minimal or may not be needed at all. The treatment objectives may be well met, but the eruption of teeth may not take place as expected, requiring a more complicated Phase II. Even in the worst case scenario, a comprehensive Phase I treatment will minimize the difficulty, time and cost of the Phase II treatment. Plus the additional benefit of providing a superior result because of the ability to work with Mother Nature and modify growth to provide a more natural result. Doing a comprehensive Phase I treatment also minimizes the need to extract permanent teeth as part of the orthodontic treatment done in Phase II.
As has been presented, a Phase I/Phase II approach to treatment may sound like you are just doing braces twice, you are really just starting the treatment early and accomplishing what you can without all the permanent teeth in place, then taking a vacation and then finishing the treatment after all the permanent teeth are erupted. The goals of Phase I are different than the goals for Phase II, but they are intertwined and are really just a continuing treatment with a break between so that you don’t get burned out or experience any of the detrimental affects of prolonged treatment. If there are skeletal discrepancies, functional interferences, or growth deficiencies/excesses, a comprehensive Phase I treatment may be indicated and the ideal antidote for avoiding future problems and making the Phase II treatment easier and less complicated. As the old-timers might say; “a stitch in time saves nine!”