Standard Retainers

Following correction of dental alveolar discrepancies, retention with standard removable appliances, such as a Schwartz plate or Hawley or Van der Linden retainers, is generally sufficient. These retainers allow good settling of the occlusion, as they involve only little interocclusal interference, if any. Settling can be satisfactorily achieved with these appliances while at the same time maintaining the alignment of the labial segments ( Figs. 9.4 and 9.5 ).

Case Study 9.1 (Fig. 9.4)

Patient: G.B., female, age 14.

Diagnostic records: models, panoramic radiograph, lateral cephalometric radiograph, intraoral/extraoral photographs.

Main findings: buccally positioned tooth 13 and right-sided unilateral open bite.

Treatment aims: alignment of tooth 13 and establishment of solid occlusion.

Appliances: Self-ligating brackets.

Archwire sequence: 0.012 SE, 0.016 SE, 0.016 × 0.022 SE, 0.018 × 0.025 SE, 0.019 × 0.025 SS.

Alternative treatment strategy: n/a.

Active treatment time: 11 months.

Retention: three-dimensional retention, allowing settling.

The modified Hawley retainer has two Adams clasps on first molars to which the labial bow is soldered. This design shortens the labial bow and makes it more resistant to deformation in comparison to a Begg retainer but yet allowing settling of the posterior occlusion.

Case Study 9.2 (Fig. 9.5)

Patient: J.H., female, age 13.

Diagnostic records: models, panoramic radiograph, lateral cephalometric radiograph, intraoral/extraoral photographs.

Main findings: deep bite and class II tendency with maxillary and mandibular anterior crowding.

Treatment aims: bite opening and alignment.

Appliances: Self-ligating brackets, anterior bite elevators.

Archwire sequence: 0.012 SE, 0.016 SE, 0.016 × 0.022 SE, 0.018 × 0.025 SE, 0.019 × 0.025 SS.

Alternative treatment strategy: n/a.

Active treatment time: 10 months.

Retention: three-dimensional retention with Hawley retainers.

Retention of Transverse Corrections

After transverse corrections (particularly expansion of the upper jaw), a Hawley retainer or Schwartz plate is customarily used for retention. These can be fitted with a partially preexpanded midline screw. If the appliance is not worn for some time, the screw can be contracted, and the plate can be inserted again and then reexpanded to its original size.

Retention of Class II Cases

Orthodontically corrected skeletal discrepancies of the class II type often benefit from long-term retention of the sagittal correction. The present authors prefer to use vacuum-formed retainers fitted with the advancement components of Kinzinger’s Functional Mandibular Advancer (FMA) ( Fig. 9.6 ).7 ^, 8 The vacuum-formed retainers provide good retention of the alignment of the labial segments while at the same time being rigid and retentive enough to allow forward positioning of the lower jaw. If required, minor tooth movement is possible with these retainers by means of an individual set-up ( Fig. 9.7 ).

Retention in Class III Cases

Further developments in patients with a previously corrected class III malocclusion are difficult to anticipate, as the residual growth potential remains unknown. It therefore seems all the more important to achieve a final result with good cusp embrasure and anterior coupling, as a tight occlusal relationship is considered to be the best form of retention for class III patients. Tissue or tooth borne functional appliances (such as Fränkel III, ‘Reverse Twin Block’ and ‘Reverse Double Plate’ respectively) should also be considered for retention of treated class III malocclusions.