Hawley’s retainer & other URA

Hawley’s retainer & other URA

Function of URA • Arch development • Arch length development • Retainer

Arch Development • Schwartz appliances • Component • Expansion screw • Clasp • Labial bow • Acrylic baseplate

Indication • Can be used for Class I or II cases, mixed or permanent dentition. • Narrow palates and/or crowded arches. • Anterior open bite cases associated with myofacial habits.

Contraindication • Lack of enough teeth or lack of enough clinical height of crowns to achieve adequate retention from clasping.

Advantages • It is removable so hygiene is excellent. • It is extremely versatile, depending on design can be used for a wide variety of cases, anomalies, and malocclusions.

Upper Schwartz • This appliance is used for bilateral cross bites and also to help eliminate anterior crowding.

Transverse appliance • A minor modification of upper Schwartz; addition of posterior bite plane • The Transverse appliance is recommended when there is an arch width deficiency in the maxilla. • It features multiple clasping and two sutural expansion screws placed on the midline for added rigidity .

Nord appliance • The Nord appliance is designed for correction of a unilateral cross bite. • It uses a smooth posterior bite plane on the side to be expanded and an indexed posterior bite plane and lingual flange on the opposite side for support andanchorage.

Three way appliance • Used in the upper arch for both lateral and anterior development

Fan gear appliance • Designed to develop the bicuspid area, it is ideal for correcting tapered arch forms.

Arch Length Development • Sagittal appliance • Components • Expansion screws • Clasp for retention and/or retraction • Acrylic baseplate

Indication • Can be used for Class I, II or III cases depending on how appliance is designed. • Mixed or permanent dentition. • Crowded arches and/or narrow palates. • Blocked out canines. • Deficient anterior maxilla. • Mesially positioned molars.

Contraindications • Lack of enough teeth or lack of enough clinical height of crowns to achieve adequate retention from clasping.

Advantages • It is removable so hygiene is excellent. • It is extremely versatile, depending on design can be used for a wide variety of cases, anomalies, and malocclusions

Anterior sagittal • To ensure anterior development, the design maximizes posterior anchorage with screw placement and occlusal indentations.

Distal sagittal • This design facilitates distal driving of posterior teeth to regain lost arch length. • To maximize distalization, splits are cut mesial to first molars.

3 screws sagittal • This features the Sagittal design with a midline expansion screw for lateral development.

Retainer • Hawley retainer • Designed by Charles Hawley • Used passively to retain teeth in their new position following orthodontic treatment • Most frequently used as retainer

Consists of: • Acrylic baseplate • Adam clasps on 6s • Labial bow with U loops

Indications: • Hold teeth in a new position after dentition has been orthodontically corrected • Prevent relapse while bone fill occurs around the roots of the moved teeth • Minor tipping movement of teeth mesio-distally and buccally • Correct simple anterior crossbites

Hawley’s Retainer • Modification: • Acrylated labial bow : to improve control of rotated teeth • Soldered labial bow to 6’s crib bridge : to minimize space re-opening in extraction site • Incorporate a bite plane for deep OB cases • Reverse U loop to improve canine control

ADVANTAGES DISADVANTAGES Simple to construct. Fabricated in lab, resulting in a reduced chair time. Can be removed for brushing, flossing and social reasons. Acrylic palate is rigid → offers significant anchorage, maintains transverse expansion. Allows more rapid vertical setting of teeth than vacuum-formed retainers, due to the lack of complete occlusal coverage. Versatile → easily modified, and can be adjusted for finishing of treatments. Durable → can last for several years Success depends on patient compliance. May be considered unaesthetic due to labial bow. Speech might be impaired. Wire crosses the occlusal plane. Only tipping movements are possible. Rotated teeth are extremely difficult to correct.

San Antonio • Similar function to Hawley’s retainer • Indicate for patient with close tooth contact making Adam clasp implausible

Dicussion • Female, 15y/o • Palatally erupted 22

Z-spring on 22 • Adam clasps on 6s • Expansion screw • Posterior bite plane • Acrylic baseplate

SITUATION 2: Patient with retroclined both upper central incisors. Aim of treatment: To procline the upper central incisors and prevent anterior crossbite URA design: Active component: Double cantilever spring (Z-spring) on 11 and 21 Retentive components: Adams clasps on first premolars and first molars, labial bow Anchorage: Adams clasps, baseplate Baseplate: Acrylic (cold-cured polymethylmethacrylate), posterior bite planes

Mechanism of action: • Double cantilever spring will cause proclination of 1 or 2 incisors • Activate by pulling away from baseplate at 45 ͦ • Labial bowhelp to retain an upper removable appliance and to guide the movement of teeth when used with other active components. • Advantage: • can be removed and cleaned • Cheaper than fixed appliance • Disadvantage: • highly depend on patient compliance • Timing: wear 24 hours except during eating and sport

Retroclined upper incisors Double cantilever Example of simple URA

Hawley’s retainer & other URA