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 themaxilla.

– 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 and anchorage.

• 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:1) Active component: Double cantilever spring (Z-spring) on 11 and

212) Retentive components: Adams clasps on first premolars and first

molars, labial bow3) Anchorage: Adams clasps, baseplate4) 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 bowhelp 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