The timing of orthodontic treatment, including dentofacial orthopedics, has variable opinions expressed in the specialty. The literature supports early treatment for many, but not all, conditions. Early intervention with rapid palatal expansion has support that is based on both anatomical and dental development. Five key reasons for early expansion are discussed in this article, which gives additional support for early application of this beneficial procedure.

1. Anatomy studies of the mid palatal suture document that the suture becomes more complex with maturity. The suture system of younger patients is very responsive to the orthopedic intervention of the expander. This benefits the maxillary complex because less pressure is needed to achieve the desired skeletal expansion. When less pressure is used we reduce the risks for negative consequences to the buccal bone. As a patient matures, there is more risk of teeth tipping with expansion and less stable orthodontic expansion rather than orthopedic expansion.

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Figure 1: The stages of suture development becoming more complex with maturity

2. Use of an expander during the early mixed dentition allows the use of the primary teeth to serve as anchors for the expansion appliance. This has important benefits to the permanent dentition that eliminates the potential negative effects that can include dehiscence of the buccal bone, gingival recession and root resorption. Expansion appliances use the strength of the roots and surrounding bone of the teeth they are attached to. In consequence, those teeth and supporting bone carry the lateral pressure of the expansion as the suture opens. When primary teeth are used to support the expander, the succedaneous bicuspids and canines have not borne any of the expansion pressure. The newly erupting teeth only benefit from the additional space development the expander has created. The acrylic bonded expander is easily constructed to adapt exclusively to the primary dentition, and has the added benefit of spreading the attachment over several teeth on each side. A banded hyrax appliance can be attached to second primary molars and canines, or the permanent first molar and primary first molar. Studies have reported using a Haas expansion appliance attached to the second primary molars and primary canines is successful and stable.

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Figure 2: Bonded expander can cover permanent or all primary teeth

3. In most cases the reason for expansion is because of the maxillary constriction or crossbite. The expansion appliance is placed into the palatal vault area as deeply as possible without impinging on palatal tissues. As a consequence the appliance will create a temporary interference with speech and swallowing. The adaptation of the neuromuscular system in younger patients is faster and will adapt more readily than older adolescent patients.

4. When teeth erupt into a prepared site with adequate bone and soft tissue support, it is the ideal scenario for long-term stability and sound periodontal support. A similar protocol is followed when preparing a site with a graft for receiving an implant or grafting in an alveolar cleft site to receive the erupting canine. To prepare the space with expansion follows the same principles for site preparation. In a crowded developing dentition, the plan to develop eruption space will decrease the risk of ectopic eruption with a compromised gingival attachment

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Figure 3: Cross bite and constricted maxilla
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Figure 4: Bone and tissue developed for erupting canines

5. The effects of a constricted maxilla goes well beyond the dentition. We are finding more evidence that maxillary constriction can be a factor in airway restriction in children. The effects of a rapid maxillary expander can include an increase in nasal airway and improved respiratory function. As airway evaluation becomes more a part of our dental exams, the benefit of early expansion can include the improvements in airway and sleep.

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Figure 5: Benefits of expansion are not limited to cross-bite correction
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Figure 6: Prepare the arch for good eruption and tissue support
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Figure 7: Narrow molar width 30 mm
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Figure 8: Post expansion width 36 mm

(Click this link for more articles by Dr. Donna Stenberg.)

Donna J. Stenberg DDS, MS, PA, Spear Visiting Faculty and Contributing Author.


Mutinelli S, Manfredi M, Guiducci A, Denotti G, Cozzani M. Anchorage onto deciduous teeth: effectiveness of early rapid maxillary expansion in increasing dental arch dimension and improving anterior crowding. Progress in Orthodontics 2015;16(1).

Cistulli PA, Palmisano RG, Poole MD. Treatment of obstructive sleep apnea syndrome by rapid maxillary expansion. Sleep 1998;21(8):831–835.

Mcnamara JA, Lione R, Franchi L, et al. The role of rapid maxillary expansion in the promotion of oral and general health. Progress in Orthodontics 2015;16(1).

​Almuzian M, Ju X, Almukhtar A, Ayoub A, Al-Muzian L, Mcdonald JP. Does rapid maxillary expansion affect nasopharyngeal airway? A prospective Cone Beam Computerised Tomography (CBCT) based study. The Surgeon 2016.


Commenter's Profile Image Ian H.
May 2nd, 2016
with the use on mini screws it is now possible to expand the palate with no force being placed on the teeth. This will allow for expansion in the early adolescent and, with surgery, the adult as well. Speaking of adults, has anyone tried Boney Block Ortho - basically mini corticotomies so the appliance move a block of bone which contains the teeth. But how do you train the tongue to move up and keep the expansion?
Commenter's Profile Image Donna S.
May 3rd, 2016
Ian, I am not familiar with Boney Block ortho. I tried to look it up but did not find anything. What you describe sounds like distraction osteogenisis. I will keep looking and let you know of anything I find. I support palatal expansion with an eight week hold after turns are completed and then a removable retainer with palatal coverage. U susally have them wear it full time for 4 months and then at night. I am usuall using the retainer for eruption guidance as well. In an expander to braces patient I use a U arch wire for 6 months, usually to adjust molar torque while I supporet the expansion. We do use swallow and tongue positioning exercises if the tongue is down or forward. Hope this helps Donna
Commenter's Profile Image Jon H.
August 5th, 2018
Hi there. What age in children would you suggest that the expansion should be performed? Also, if the child is over 6 years of age, then won't the first permanent molars be subjected to the expansion forces as well as the deciduous teeth, which if I understood correctly were more favourable teeth to expand? Many thanks, Jon Henley
Commenter's Profile Image Donna S.
August 8th, 2018
Hi Jon, thanks for the question. I have balanced the timing of expansion with the needs of the patient and the ability of the patient to manage the expander. For the very young patient I always want the parents and patient on board with the process. I have done expansion as early as age 5. Today with airway as a consideration there is discussion about expanding even earlier. I have also been using alternative methods using a light wire and also clear aligners to slowly develop the arch and this seems to be giving promising results. The typical hyrax style expander is pretty bulky so it is nice to have an alternative for the smaller patient. As to the primary teeth versus the permanent teeth, it is usually the bicuspids that suffer from the buccal bone dehiscence and the molar seems to stay protected, however that may not always be the case for every patient. The teeth are providing the anchorage for the skeletal (bone) expansion but will also express dental movement. I think there are benefits to using all primary dentition if the patient and family are ready for treatment. Hope that helps to answer your questions Jon. Donna