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Orthodontics Research Supporting Your Practice

What are the effects of orthodontic treatment for posterior crossbites?


Healthy Woman Teeth And Dentist Mouth MirrorThis summary is based on the Cochrane Oral Health Group review: Orthodontic treatment for posterior crossbites (August 2014)

Paola Agostino, Alessandro Ugolini, Alessio Signori, Armando Silvestrini-Biavati, Jayne E Harrison, Philip Riley



A posterior crossbite occurs when the top back teeth bite inside the bottom back teeth. It occurs when the top teeth or jaw are narrower than the bottom teeth and can happen on one or both sides of the mouth. The condition affects between 1% and 16% of children who only have their baby teeth. Most posterior crossbites (50% to 90%) remain even when the permanent teeth erupt. In a minority of children, the problem self corrects.

In order to obtain a more comfortable bite, the lower jaw shifts to one side into a position that allows more teeth to come into contact. However, this shifting of the lower jaw may lead to tooth grinding, and this may lead to other dental problems including the tooth surface being worn away, abnormal growth and development of the teeth and jaws, and jaw joint problems.

Therefore, there is a need to find safe and effective treatments to correct posterior crossbites or expand the top back teeth, or both. One alternative is using orthodontic treatments. This can be more effective in children because the two halves of the roof of the mouth have not fully joined yet, so the top back teeth can be expanded more easily.

Several treatments have been recommended to correct this problem. Some treatments widen the upper teeth while others are directed at treating the cause of the posterior crossbite (e.g. breathing problems or sucking habits). Most treatments have been used at each stage of dental development.

Purpose of the Review

To assess the effects of orthodontic treatment for posterior crossbites.

Key Findings

  • There is some evidence to suggest that the quad-helix (fixed) appliance may be more successful than removable expansion plates at correcting posterior crossbites and expanding the top back teeth for children with a mixture of baby and adult teeth (aged eight to 10 years).
  • The remaining evidence did not allow the conclusion that any one treatment is better than another.


List of references included in the review (PDF)



  1. Mark Antosz January 6, 2015

    This is a very disappointing report and demonstrates the inadequacy that is the foundation of Cochrane literature surveys. A Cochrane review is not research, it is a research summarization. Its proponents like to use the phrase, “The best available…”. Well, if the “best available” is weak research, the Cochrane review will be weak at best, and completely misleading in the worst.
    Any orthodontist worth his/her salt who’s been out in the trenches will tell you that dentoavleolar correction (i.e. removable appliances) of a true skeletal posterior crossbite has no reasonable chance of success because you just tip teeth – you don’t get orthopaedic correction. There are then 2 possible outcomes. It relapses, and you have the crossbite back again, OR it relapses and you end up with an anterior open bite because of subsequent extrusion of the relapsing molars. I’ve seen both all too often with half-hearted attempts at interceptive care. Fixed appliances, be they quad helixes (which are uncomfortable and awkward to manage) or RPEs are reliable and predictable.
    There is no mention made of the unilateral crossbite in particular – which is the most important to treat early because of the subsequent creation of a mandibular asymmetry (which is a difficult and vexing problem for an orthodontist to manage – at least without surgery – when the teenager with a unilateral crossbite walks in through the door).
    Age of treatment is critical as well. The earlier you correct it, the more likely you will get spontaneous resolution of the mandibular asymmetry. And it’s incredibly easy to do – even in a 4- or 5- year old. Best “bang for the buck” of all orthodontic treatment offered.
    I think you could have offered our colleagues a lot more useful information that could have made a more significant impact on our patients.

  2. Dr.Gene Jensen January 6, 2015

    There are many types of cross bites, numerous etiologies, several philosophies of treatment, as well as, the most appropriate time to treat this debilitating functional, dento-skeletal, and sometimes cosmetically disfiguring malocclusion.Cross bites can cause, or contribute to the following maladies, if not corrected i.e. severe maxillary crowding, impacted canines, asymmetrical growth and development of teeth and jaws, chronic cheek and tongue biting leading to leukoplakia and precarcinogenic mucosa later in life, speech impediments, severe bruxing and clenching, masticatory inefficiency, premature attrition, dental recession, idiopathic and spontaneous tooth movement, excessive secretions of hydrochloride acid, gastric juice and bile, in conjunction with reverse peristalsis, ulcerations, and halitosis (irritable bowel syndrome), malnutrition, temporomandibular joint dysfunction, associated with headaches, earaches, neck and shoulder pain, loss of hearing, vertigo, tinnitus, meniscus subluxation (lockjaw), TMJ crepitus distorted/asymmetrical smile and physiognomy, and last but not least, condylar osteoarthric degeneration. During the growing phase i.e. mixed dentition, to, and including puberty, (approximately 7 to 14 years of age)on both males and females, we use only an 016″ expanded maxillary arch wire, in conjunction with 1/4 inch, 6 ounce cross elastics on one, or both sides, depending upon whether we are dealing with a unilateral or bilateral cross bite. If it’s a unilateral cross bite we use a straight vertical 1/8 inch, 4 ounce elastic on the non cross bite side in conjunction with the 1/4″,6 ounce elastic on the cross bite side. We have not had to use any other kind of expansion appliance in over 25 years. After puberty (approximately 14 years of age) when I believe the mid-palatial suture has closed, I will create a 2mm space between the mx 2’s and 3’s and have the oral and maxillofacial surgeon perform the expansion in the OR, under conscious sedation, which takes approximately 45 minutes. Usually the 8’s are surgically removed at the same time, which takes approximately 20 more minutes. Post-surgically we maintain the stability of the cross bite correction with the technique, as above with the elastics for 10 weeks. If the cross bite was the only problem, we remove the fixed appliances (braces) and insert an Essix(Biostar) retainer, on the same day, to be worn full-time for 2 weeks, and then at night time, on a decreasing scale, over 3 years, decreasing at the rate of one night every 6 months, until down to 0. I have never had a problem, to date, using this approach. I hope these suggestions will be of some assistance to those of you who are still struggling with the diagnosis, timing, and treatment of that most challenging of malocclusions,the “cross bite”.


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