Arch Expansion As Method Of Gaining Space Question And Answers

Arch Expansion As a Method Of Gaining Space

Question 1. What are the various methods of gaining space in orthodontics? Describe in detail rapid maxillary expansion.
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Enumerate the various methods of gaining space in orthodontics. Describe rapid maxillary expansion in detail.
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Enumerate methods of gaining space during orthodontics treatment. Describe rapid maxillary expansion in detail.
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Enumerate space-gaining methods in orthodontics. Describe rapid maxillary expansion.
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Enumerate various methods of gaining space. Describe in detail the indication, contraindication, effects on skeletal and dental tissues, and activation schedule of rapid maxillary expansion.
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Describe rapid maxillary expansion in detail.
Or
Enumerate various indications for rapid maxillary expansion. Describe in detail the effects and appliances used for rapid maxillary expansion.
Answer. Space is required for correction of crowding, retraction of proclined teeth, leveling the steep curve of Spee, derotation of anterior teeth, and for correction of unstable molar relation.

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Methods of Gaining Space

Methods of gaining space are divided into two types, i.e.

• Procedures with reduction of tooth material
  • Proximal stripping or slicing.
  • Extraction.
• Procedures without reduction of tooth material
  • Expansion.
  • Labial proclination.
  • Distalisation of molars.
  • Derotation of posterior teeth.
  • Uprighting.

Rapid Maxillary Expansion (RME)

An apparently complex yet relatively simple procedure in orthodontics is palatal expansion.

• Rapid maxillary expansion is also known as the “rapid palatal expansion” or “split palate”.
• It is a skeletal type of expansion that involves the separation of the mid-palatal surface and the movement of maxillary shelves away from each other.
• Emerson C Angel is considered the father of rapid maxillary expansion.
• Angel, first time in 1860, used a jack screw type of device between the maxillary premolar.
• The intermaxillary and the interpalatine sutures are collectively called mid-palatine sutures, rapid maxillary expansion should be initiated before the ossification of mid-palatine sutures.
• A broad range of ossification time is 15 to 27 years.

Indications for Rapid Maxillary Expansion

Orthodontic Indications

• In unilateral or bilateral posterior skeletal crossbite.
• In narrow maxilla in certain class 2 cases.
• In class 3 malocclusion.
• In collapsed maxillary arch due to clef palate.
• Along with reverse pull headgear for loosening the sutures.
• In anterior crossbite for gaining space.
• In high-angle cases, here bonded RME is used.

Medical Indications

• In poor nasal airway
• In septal deformity
• In recurrent ear or nasal infections
• In cases of asthma
• In patients with allergic rhinitis
• In cases of septal deformity.

Types of Appliances Used

Broadly classified as:

• Removable appliances.
• Fixed appliances.
  • Bonded or banded.
  • Tooth borne or tooth and tissue borne.

Removable Appliances

A removable type of rapid maxillary expansion device consists of a split acrylic plate with a midline screw. The appliance is retained using clasps on the posterior teeth.

• Treatment during the deciduous or early mixed dentition is more favorable in producing skeletal effects.
• Disadvantage: Need for patient cooperation.
• Difficulty in relating the palate inside the mouth.

Fixed Appliances

Appliances that are fixed onto the teeth are more reliable and found to produce consistent skeletal effects.

Banded rapid maxillary expansion appliances

Classification of banded fixed appliances

Tooth and Tissue Borne Appliances

• Derichsweiler type.
• Hass type.

Tooth borne appliances

• Isaacson type.
• Biedermann type.

Derichsweiler type

• The first premolar and fist molars are banded.
• Wire tags are soldered onto the palatal aspect of the band.
• Wire tags get inserted into a split palatal acrylic incorporating a screw at its center.
• Acrylic adapts the palate and is in two halves to permit activation of the screw.

Hass type

• First premolar and fist molar are banded.
• A thick stainless steel wire of 1.15 mm diameter is soldered on the buccal and lingual side of bands.
• The lingual extensions are longer and get embedded in the palatal acrylic.
• The split palatal acrylic has a midline screw.

Isaacson type

• This is a tooth-borne appliance without any acrylic palatal covering.
• This appliance uses spring loaded screw called a MINNE expander.
• The fist premolar and fist molar are banded.
• Metal flanges are soldered onto the buccal and lingual sides.
• The expander consists of a coil spring having a nut.
• This coil spring is made to extend between the lingual metal flanges that have been soldered.
• The expander is achieved by closing the nut so that the spring gets compressed.

Biedermann type

• This type of appliance uses a specific type of screw called HYRAX (Hygienic rapid expander).
• It has heavy wires which are adapted, welded, and soldered to a palatal aspect of bands in molar and premolar.

Bonded rapid maxillary expansion appliance

In bonded rapid maxillary expansion bands are replaced by metallic cap splints or acrylic covers.

Metal cap splints

• Casting of cap splint to all the teeth is done which are prepared in which screw has to be soldered.
• The complete assembly is cemented or bonded.

Acrylic splint

• A thick stainless steel wire is adapted from premolar to molar buccally and palatally.
• Soldering of screw is done with wire.
• Covering of acrylic is done at occlusal, buccal and palatal occlusal third from premolar to molar.
• Complete assembly is bonded or cemented.

Principle of Rapid Maxillary Expansion

Management by Appliance

According to Timms, management by appliance should be done at three ages, i.e.

Retention of Appliance

• The same rapid maxillary expansion appliance should act as a retainer for the first three months.
• A removable retainer should be given from the 4th month.
• A removable retainer should be worn full time for 9 months and after 9 months half-time wear is advised.

Effects of Rapid Maxillary Expansion

Effects of rapid maxillary expansion are divided into effects on the following tissues:

Changes in Bone

• Lateral movement of the maxilla.
• Rotation of maxilla with fulcrum at frontonasal suture.
• Nasal airways get increased and airway resistance decreases.
• Rotation of the mandible occurs in downward and backward directions.
• Mandibular angle increases.

Changes in Suture

• Due to the opening of sutures, a space is formed which is filled by blood and tissue fluid.
• Atthe  edge of the palatal process, bone deposition occurs.
• Bone is formed in the space.

Changes in Dentition

• Labial movement of teeth because of translation.
• Buccal inclination of posterior teeth increases.
• Posterior teeth get slightly extruded.
• Midline diastema occur.

Contraindication of Rapid Maxillary Expansion

• Single tooth crossbite.
• Uncooperative patient.
• After ossification of mid-palatal suture.
• Skeletal asymmetry of maxilla and mandible and adult cases with severe anteroposterior skeletal deformities.
• Vertical grooves with steep mandibular plane angle.
• As posterior teeth are used as anchors to move bones apart, the procedure is not indicated in periodontally weak dentition.

Question 2. Briefly differentiate between slow and rapid expansion.
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Distinguish between rapid maxillary expansion and slow maxillary expansion.
Answer.