SECTION 16

ORTHODONTIC INSTRUMENTS

Orthodontics is the study of the diagnosis, prevention and treatment of irregularities of the teeth and jaws. Orthodontic instruments are used in conjunction with fixed and removable appliances.

Figure 16.1

Figure 16.2

ORTHODONTIC APPLIANCES

FIGURE 16.1

Name

Removable orthodontic appliance (Hawley retainer)

Features

• Is removable and depends on patient compliance for success
• Constructed from acrylic and a combination of stainless steel retentive clasps and springs
• The acrylic of a removable appliance can be adjusted by grinding with a straight handpiece and acrylic bur, and the clasps and spring can be adjusted with a variety of orthodontic pliers

Varieties

There are many types of removable appliances depending on the needs of the patient (e.g. expansion appliances and Hawley retainers)

FIGURE 16.2a, b, c

Name

Fixed orthodontic appliances: (a) Rapid palatal expander (b) Metal fixed appliance (c) Ceramic fixed appliance

Features

• Are cemented to the teeth and cannot be removed by the patient
• Consist of a combination of orthodontic bands, orthodontic brackets or orthodontic wires
• Require special orthodontic pliers for adjustments

Varieties

There are many types of fixed appliances depending on the needs of the patient (e.g. braces and palatal expanders)

Figure 16.3

Figure 16.4

FIGURE 16.3

Name

Headgear and face bow

Function and features

• Has an inner bow (fits into the buccal tubes of the fixed appliance) soldered to an outer bow (can be attached to a strap)
• The headgear is worn outside the mouth, and the face bow is attached to the buccal tubes intra-orally
• The orthodontic headgear is used to prevent establishment of deep overbites by restricting the growth of the maxillary arch. Can also be used to prevent mesial drifting of maxillary molars when teeth have been extracted anterior to the molars
• The strap has a safety mechanism which prevents the bow from springing back at the patient if it is pulled forwards

Varieties

Different sizes available colour coded

ORTHODONTIC MATERIALS

FIGURE 16.4

Name

Elastic separators

Function and placement

• Used to create inter-proximal space to allow orthodontic bands to be placed
• Separators can be placed with floss or separator placing pliers (see Figure 6.11)

Figure 16.5

Figure 16.6

FIGURE 16.5

Name

Orthodontic band

Function, features and placement

• Used to secure auxiliary devices to aid in tooth positioning
• Stainless steel bands are cemented on posterior teeth
• Pre-formed – variety of sizes available
• Occlusal edge is slightly rounded, whereas gingival edge is straight
• Placement is preceded by placement of separators to create interproximal space

Varieties

Available in different shapes and sizes

FIGURE 16.6a, b

Name

(a) Metal orthodontic bracket (b) Ceramic orthodontic bracket

Function and features

• Used to secure an orthodontic archwire in place
• Most often bonded to the buccal surface of the tooth
• Orthodontic brackets may have coloured indicators to help orientate placement
• Orthodontic brackets often have a textured back that aids in bonding to the tooth

Varieties

• Many different brands and sizes available
• Can be made from different materials (e.g. stainless steel and ceramics)

Figure 16.7

Figure 16.8

FIGURE 16.7

Name

• Orthodontic archwire

Function and mechanism of action

• Archwires are tied into orthodontic brackets that have been previously bonded to teeth, and these act as a track to facilitate movement of teeth
• The archwire is pre-formed. When tied into the bracket its shape may be altered. This results in force being applied to the teeth as the archwire tries to regain its original shape

Varieties

• Available in different shapes and diameters
• Made from many different materials, e.g. stainless steel and nickel titanium

FIGURE 16.8

Name

Elastomeric modules

Function and directions for use

• Used to ligate or hold the orthodontic archwire in place
• Used with mosquito artery forceps or Mathieu ligature pliers to place around orthodontic brackets
• One use and changed each time the archwire is changed

Varieties

• Can be made from a variety of materials
• Available in many colours

Figure 16.9

Figure 16.10

FIGURE 16.9a, b

Name

Ligatures

Function and directions for use

• Used to ligate or hold the orthodontic archwire in place
• Used with mosquito artery forceps or Mathieu ligature pliers to place around orthodontic brackets
• Changed each time the archwire is changed
• The excess ligature wire is cut with various orthodontic pliers and should be disposed of in the sharps’ bin
• One use

Varieties

• Can be made from a variety of materials
• Different types: (a) long ligature, (b) ‘quick ligs’ and Kobayashi tie hooks that facilitate tying elastics around

FIGURE 16.10

Name

Patient relief wax (bee’s wax)

Function

Given to the patient after fixed appliance placement to help relieve discomfort from tissue trauma

Figure 16.11

ORTHODONTIC INSTRUMENTS

FIGURE 16.11a, b

Name

Separator placing pliers

Function and features

• Used for placing elastic separators interproximally
• Single-ended instrument – handle is adapted for a palm grasp

Varieties

Different sizes and shapes are available

False friends

Rubber dam clamp forceps and Coons ligature pliers

FIGURE 16.12

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