What do systematic reviews say?

Two-band palatal expander with slow expansion vs Two-band palatal expander with rapid expansion

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  7 months after start of treatment
  Martina 2012: slow 6.3 mm (SD 2.1) vs rapid 5.7 mm (SD 1.6); reported as no statistically significant difference in text (PUB2 MD 0.60, 95% CI -0.85 to 2.05); Table 1 lists P<0.001 (discrepant)
  1 study · 26 participants
  GRADE not reported

Fixed tooth-borne expansion (Hyrax) vs Bonded expander plate (acrylic)

Fixed tooth-borne Hyrax expander showed no clear difference in molar expansion compared with bonded expander plate (acrylic); GRADE not reported.

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  1 week after completion of expansion
  MD 0.36 [-0.72, 1.44]
  1 study
  GRADE not reported

Fixed expander with differential opening expansion (DOE) vs Fixed fan-type expander

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes
  Massaro 2020: DOE 5.10 (SD 1.17) mm vs fan-type 2.23 (SD 0.75) mm; P<0.001 (favours differential opening)
  1 study
  GRADE not reported

Four-point expansion appliance (Hyrax) vs Two-point expansion appliance

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  3 months after completion of expansion
  Lamparski 2003: not reported by group; 'no significant differences were found'
  1 study
  GRADE not reported

Fixed tooth-borne expansion (Hyrax) vs Bonded Hyrax (tooth/tissue-borne)

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  3 months after completion of expansion
  Asanza 1997: banded 6 mm (min 4.3-max 7.2) vs bonded 5.9 mm (min 3.2-max 7.7); P=NS (no SD reported); no significant difference in tipping or symmetrical expansion
  1 study
  GRADE not reported

Semi-rapid maxillary expansion vs Rapid maxillary expansion

Semi-rapid maxillary expansion showed no clear difference in molar expansion compared with rapid maxillary expansion; GRADE not reported.

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes
  MD 0.60 [-0.55, 1.75]
  1 study · 35 participants
  GRADE not reported

Quad-helix plus multi-bracket appliance vs Expansion arch plus multi-bracket appliance

Quad-helix plus multi-bracket appliance showed no clear difference in molar expansion compared with expansion arch plus multi-bracket appliance; GRADE not reported.

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  12 weeks after start of treatment
  MD -0.55 [-1.34, 0.24]
  1 study · 55 participants
  GRADE not reported

Haas expander anchored on deciduous second molars vs Haas expander anchored on permanent first molars

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  after 5-month retention period
  Ugolini 2015: deciduous 4.3 mm vs permanent 5.8 mm; P<0.01 (favours permanent-molar anchorage)
  1 study
  GRADE not reported

Hyrax with conventional expansion screw vs Hyrax with NiTi memory expansion screw

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  after 6-month retention period
  Halicioglu 2014: conventional Hyrax 8.41 (SD 2.09) mm vs NiTi Hyrax 8.94 (SD 1.73) mm; no statistically significant differences for any outcome
  1 study
  GRADE not reported

Fixed bonded Hyrax appliance followed by U-bow activator therapy vs no treatment

Fixed bonded Hyrax appliance followed by U-bow activator therapy showed no clear difference in molar expansion compared with no treatment; GRADE not reported.

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  12 months after start of treatment
  U-bow activator 5.1 mm vs untreated 0.8 mm; P<0.001 (no SD reported); significant in favour of treatment
  1 study · 66 participants
  GRADE not reported

Fixed tooth-borne expansion (Hyrax) vs Fixed fan-type expander

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  post-treatment 3 weeks
  Gopalakrishnan 2017: Hyrax 8.00 (SD 2.19) mm vs fan-type 1.83 (SD 0.41) mm; P<0.001 (greater intermolar expansion with Hyrax)
  1 study · 12 participants
  GRADE not reported

Bonded Minne appliance (slow maxillary expansion) vs Banded Minne appliance (slow maxillary expansion)

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  7 to 15 weeks after start of treatment
  Bonded Minne 7.9 mm (SD 1.5) vs Banded Minne 8.3 mm (SD 1.1); P=NS
  1 study
  GRADE not reported

Expansion plate with conventional expansion screw vs Expansion plate with spring-loaded expansion screw

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes
  Oshagh 2012: no significant differences in discomfort and arch size changes; results inadequately reported (no usable data)
  1 study
  GRADE not reported

Fixed tooth-borne expansion (quad-helix) vs observation

Fixed tooth-borne expansion (quad-helix) probably leads to higher molar expansion (inter-molar distance) compared with observation (no treatment) (moderate certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children (7 to 11 years)
  MD 4.71 [4.31, 5.10]
  3 studies · 146 participants
  Moderate

Fixed tooth-borne expansion (Hyrax) vs Fixed tooth-tissue-borne expansion (Haas)

Fixed tooth-borne expansion (Hyrax) showed no clear difference in molar expansion (inter-molar distance) compared with fixed tooth-tissue-borne expansion (Haas) (moderate certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children
  MD -0.15 [-0.86, 0.56]
  2 studies · 46 participants
  Moderate

Fixed tooth-borne expansion (quad-helix) vs Removable tooth-borne expansion (expansion plate)

Fixed tooth-borne expansion (quad-helix) leads to higher molar expansion (inter-molar distance) compared with removable tooth-borne expansion (expansion plate) (high certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children (7 to 11 years)
  MD 1.48 [0.91, 2.04]
  3 studies · 151 participants
  High

Fixed tooth-borne expansion (Hyrax) vs observation

Fixed tooth-borne expansion (Hyrax) probably leads to higher molar expansion (inter-molar distance) compared with observation (no treatment) (moderate certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children
  MD 5.80 [5.15, 6.45]
  2 studies · 71 participants
  Moderate

Bone-borne expansion vs Fixed tooth-borne expansion (Hyrax)

Bone-borne expansion showed no clear difference in molar expansion (inter-molar distance) compared with fixed tooth-borne expansion (Hyrax) (low certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children and adolescents
  MD -0.14 [-0.85, 0.57]
  2 studies · 81 participants
  Low

Removable tooth-borne expansion (expansion plate) vs observation

Removable tooth-borne expansion (expansion plate) probably leads to higher molar expansion (inter-molar distance) compared with observation (no treatment) (moderate certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children (7 to 11 years)
  MD 3.30 [2.88, 3.73]
  3 studies · 145 participants
  Moderate

Fixed tooth-bone-borne expansion vs Fixed tooth-borne expansion (Hyrax)

Fixed tooth-bone-borne expansion showed no clear difference in molar expansion (inter-molar distance) compared with fixed tooth-borne expansion (Hyrax) (low certainty).

• Orthodontic treatment for posterior crossbites 2021 · Cochrane All outcomes

  Children
  MD 0.66 [-0.04, 1.36]
  2 studies · 65 participants
  Low