Key messages
Orthodontic treatment with quad-helix (fixed) or expansion plates (removeable) is effective for correcting posterior crossbite correction in children. Quad-helix is probably even more effective than expansion plates. For adolescents, there is probably no difference between Hyrax and Haas for posterior crossbite correction.
What is the problem?
Posterior crossbite occurs when the top teeth or jaw are narrower than the bottom teeth. It can happen on one side or both sides of the dental arches. This condition may increase the likelihood of dental problems (e.g. tooth wear), abnormal development of the jaws, joint problems, and unbalanced facial appearance. Posterior crossbites affect around 4% and 17% of children and adolescents in Europe and America.
Different treatment approaches have been proposed, resulting in many different braces being produced. The basic treatment to correct crossbite correction treatment involves using an orthodontic device on the palate (roof of the mouth) to expand the upper jaw by exerting pressure on both sides of the jaw. The devices can be fixed (e.g. quad-helix, Haas, Hyrax expander) or removable (e.g. expansion plate). Fixed appliances are bonded to the teeth, while removeable devices can be taken out of the mouth by patients.
What did we want to know?
We wanted to know the effects of different braces for posterior crossbite correction.
What did we do?
We searched for studies that assessed the effectiveness of braces used to correct posterior crossbites.
What did we find?
We found 31 studies with 1410 children and adolescents who were randomly assigned to a treatment or no treatment group. Thirteen studies included children (7 to 11 years old), 12 included adolescents (12 to 16 years old), and six included both. Eight studies were conducted in Turkey, four in Brazil, four in Sweden, three in the USA, three in Italy, two in Canada, and one each in Germany, UK, Switzerland, Iran, Spain, India, and Australia. Twenty-seven studies were carried out in universities and clinical centres, one study in private practice, and three did not state the location.
What were the main results?
For children, expansion of the upper arch with fixed or removable braces can correct posterior crossbites.
When testing fixed and removable braces against each other, the studies found that quad-helix (fixed appliance) was more successful than expansion plate (removable appliance) and that treatment with quad-helix took less time.
For other comparisons between different types of treatments, there was no evidence to show that one worked better than another, but we had moderate to low certainty in the results, so future research may change them.
How reliable are these results?
Our confidence in the results is high to moderate for the main results. For the other comparisons, our confidence in the results is low.
How up-to-date is this review?
This review is an update. The evidence is current to April 2021.
For children in the early mixed dentition stage (age 7 to 11 years old), quad-helix and expansion plates are more beneficial than no treatment for correcting posterior crossbites. Expansion plates also increase the inter-canine distance. Quad-helix is more effective than expansion plates for correcting posterior crossbite and increasing inter-molar distance. Treatment duration is shorter with quad-helix than expansion plates.
For adolescents in permanent dentition (age 12 to 16 years old), Hyrax and Haas are similar for posterior crossbite correction and increasing the inter-molar distance.
The remaining evidence was insufficient to draw any robust conclusions for the efficacy of posterior crossbite correction.
A posterior crossbite occurs when the top back teeth bite inside the bottom back teeth. The prevalence of posterior crossbite is around 4% and 17% of children and adolescents in Europe and America, respectively. Several treatments have been recommended to correct this problem, which is related to such dental issues as tooth attrition, abnormal development of the jaws, joint problems, and imbalanced facial appearance. Treatments involve expanding the upper jaw with an orthodontic appliance, which can be fixed (e.g. quad-helix) or removable (e.g. expansion plate). This is the third update of a Cochrane review first published in 2001.
To assess the effects of different orthodontic treatments for posterior crossbites.
Cochrane Oral Health's Information Specialist searched four bibliographic databases up to 8 April 2021 and used additional search methods to identify published, unpublished and ongoing studies.
Randomised controlled trials (RCTs) of orthodontic treatment for posterior crossbites in children and adults.
Two review authors, independently and in duplicate, screened the results of the electronic searches, extracted data, and assessed the risk of bias of the included studies. A third review author participated to resolve disagreements. We used risk ratios (RR) and 95% confidence intervals (CIs) to summarise dichotomous data (event), unless there were zero values in trial arms, in which case we used odds ratios (ORs). We used mean differences (MD) with 95% CIs to summarise continuous data. We performed meta-analyses using fixed-effect models. We used the GRADE approach to assess the certainty of the evidence for the main outcomes.
We included 31 studies that randomised approximately 1410 participants. Eight studies were at low risk of bias, 15 were at high risk of bias, and eight were unclear.
Intervention versus observation
For children (age 7 to 11 years), quad-helix was beneficial for posterior crossbite correction compared to observation (OR 50.59, 95% CI 26.77 to 95.60; 3 studies, 149 participants; high-certainty evidence) and resulted in higher final inter-molar distances (MD 4.71 mm, 95% CI 4.31 to 5.10; 3 studies, 146 participants; moderate-certainty evidence).
For children, expansion plates were also beneficial for posterior crossbite correction compared to observation (OR 25.26, 95% CI 13.08 to 48.77; 3 studies, 148 participants; high-certainty evidence) and resulted in higher final inter-molar distances (MD 3.30 mm, 95% CI 2.88 to 3.73; 3 studies, 145 participants, 3 studies; moderate-certainty evidence). In addition, expansion plates resulted in higher inter-canine distances (MD 2.59 mm, 95% CI 2.18 to 3.01; 3 studies, 145 participants; moderate-certainty evidence).
The use of Hyrax is probably effective for correcting posterior crossbite compared to observation (OR 48.02, 95% CI 21.58 to 106.87; 93 participants, 3 studies; moderate-certainty evidence). Two of the studies focused on adolescents (age 12 to 16 years) and found that Hyrax increased the inter-molar distance compared with observation (MD 5.80, 95% CI 5.15 to 6.45; 2 studies, 72 participants; moderate-certainty evidence).
Intervention A versus intervention B
When comparing quad-helix with expansion plates in children, quad-helix was more effective for posterior crossbite correction (RR 1.29, 95% CI 1.13 to 1.46; 3 studies, 151 participants; moderate-certainty evidence), final inter-molar distance (MD 1.48 mm, 95% CI 0.91 mm to 2.04 mm; 3 studies, 151 participants; high-certainty evidence), inter-canine distance (0.59 mm higher (95% CI 0.09 mm to 1.08 mm; 3 studies, 151 participants; low-certainty evidence) and length of treatment (MD −3.15 months, 95% CI −4.04 to −2.25; 3 studies, 148 participants; moderate-certainty evidence).
There was no evidence of a difference between Hyrax and Haas for posterior crossbite correction (RR 1.05, 95% CI 0.94 to 1.18; 3 studies, 83 participants; moderate-certainty evidence) or inter-molar distance (MD −0.15 mm, 95% CI −0.86 mm to 0.56 mm; 2 studies of adolescents, 46 participants; moderate-certainty evidence).
There was no evidence of a difference between Hyrax and tooth-bone-borne expansion for crossbite correction (RR 1.02, 95% CI 0.92 to 1.12; I² = 0%; 3 studies, 120 participants; low-certainty evidence) or inter-molar distance (MD −0.66 mm, 95% CI −1.36 mm to 0.04 mm; I² = 0%; 2 studies, 65 participants; low-certainty evidence).
There was no evidence of a difference between Hyrax with bone-borne expansion for posterior crossbite correction (RR 1.00, 95% CI 0.94 to 1.07; I² = 0%; 2 studies of adolescents, 81 participants; low-certainty evidence) or inter-molar distance (MD −0.14 mm, 95% CI −0.85 mm to 0.57 mm; I² = 0%; 2 studies, 81 participants; low-certainty evidence).