Methods of Space Gaining

Indication :

1.  Minimal space required 2.5-3 mm

2.  Good oral hygiene pat.

3.  When there s excess tooth material

Contraindication:

1.  Young pat.(large pulp)

2.  Pat. Who are susceptible to carries.

Advantage:

1.  Avoid extr.

2.  Tooth material excess can be reduced achiving better interdigitation, overbite & overjet.

3.  Broad contact add stability.

4.  Localized malalignment can be corrected without involving too many teeth.

Disadvantage :

1.  Sensitivity.

2.  Roughened surface of enamel incr. car. Susceptibilty.

3.  The shape created may not be asthetic.

4.  Food lodgment.

Procedure:

1.  Assessing space requrement.(not more than 2.5-3 mm).

2.  Selecting the teeth(which have excees tooth mat. Less aesthetic area)

3.  Determine the amount of enamel to be stripped(no more than half the enamel thickness)

4.  Enamel stripping(distriputed over large number of teeth).

Enamel stripping :

Is done by :

*Safe side (one side cut).

*Coarse medium or fine.

*Most common fine.

*Provided with special holder.

1-Metal abrasive strips.

2- Perforated diamond disc :

*flixible.

*strip the both adjacent teeth.

3- thin fissure bur :

*straight or taper.

* Leave deep scar(must be followed by abrasive strip)

Uprighting the tilted post . Teeth:

*Tilted post. Teeth always occupy more space.

*Molars tend to tip mesially when the Es are:-

           *lost early.

          *Decayed on distal surface & not restored at

               appropriate   time or    with ideal contour.

*Uprighting of molars can lead to arch length

gain of 1 -1.5 mm.

Done By:

Fixed appliance

Lip bumper

Space regainer

Derotation  the tilted post . Teeth:

*rotated post. Teeth occupy more space so derotation can help to regain space.

*The regained space depend on the rotated tooth & the extent of rotation.

*Molars occupy more space as compared to

premolar where as the rotated ant.

Teeth occupy lees space.

*Achieved by using :

couple force system.

Fixed appliance system with

 two point  contact more

efficient rotation control.

Proclination of the ant. Teeth:

Carried out in cases where these teeth are retroclined or their proclination will not affect the soft tissue profile.

Achived by Z spring or screw(medium, mini, micro screw) or fixed appliance

Arch Expansion :

One of the oldest means of creating space Subjected to a lot of controversies (rapid expansion vs slow expansion)till what age? timing? how much is enough?

Mechanism of action:

By splitting the mid palatine sutures(the rationale being that if extreme forces applied on to palatal shelves, the interlying sutures splits & result in true skeletal changes).the teeth are used for the purpose of transmitting force on to the bones.

*Midline diastema is clearly appears within days of initiating RME

*The diastema half the distance by which the screw activated.

*The diastema reported to close within 6 months due to trans-septal fiber traction.

The max post. Teeth tend to tip buccally due to the compresion of PDL on the pressure side, there’s bending of the adjacent alveolar process.

Rapid maxillary expansion (RME) :

Indication:

Growing individual with severely constricted maxillary arches involving airway impairment or mouth breathing tendencies.

Also

1-post. Cross bite with real max. dificiency.

2-cleft patient.

3-cl.III cases with minor max deficiency.

Types:

1-removable appliance

2- fixed appliance:

A- tooth borne                        Isaacson appliance

                                                hyrax appliance

B-tooth & tissue borne                           Derichsweiler appliance

                                                                 Hass appliance

Removable appliance :

*The efficiency is doubtful.

*Consist of screw in the midline with retentive clasp on post teeth & the acrylic plate is split in the middle.

*More effective when used in early mixed dentition.

*its  efficiency in the late mixed dentition & older pati. Suspected because of the ossification of the mid palatal suture

Fixed RME Appliance:

Isaacson appliance:

*Tooth borne appliance

*Consist of:

1.  Metal framework soldered both labially as well as palatally on the first premolar & molar bands.

2.  Spring loaded screw which soldered on palatal extension  of the metal frame work.

Hyrax RME appliance:

*it’s name means (hygienic)

*Consist of screw has heavy wire extension which adapted to follow the contour of the palate & are soldered to either metal bands or embeded in acrylic splints.

Derichsweiler RME appliance :

Wire tags are soldered to premolar & molar bands which are incorporated in acrylic plate which contain ascrew in the midline

Rarely used nowadays

Hass RME appliance :

Rigid appliance not only transmit forces on to the teeth but also on to the palatal shelves directly.

*Has apalatal extension 1.2 mm diameter

Incorporated in acrylic plate which contain expansion screw

Retention following RME therapy :

To prevent relapse:

*the same appliance by immobilizing the screw using cold cure acrylic.

*or TPA transpalatal arch.

Slow expansion devices:

Indication :

*Correction of unilateral crossbite:

*Correction of V shaped arches as in thumb   suckers

*Minimal crowding in the upper arch 1-2 mm

*Elimination of displacement.

Appliance:

1.  Screws.

2.  Coffin.

3.  Quad helix.

4.  Ni _ ti expander.

5.  Schwarz appliance

Coffin spring :

The appliance consists of an omega shaped 1.2 mm diameter wire, with the base of the omega placed posteriorly in the midline. Two separate acrylic wings are made around the wire framework on the slopes of the palate, these also contain the retentive clasps .

The quad-helix consists of two anterior and two posterior helices. The portion of wire in between the two anterior helices is called the anterior bridge and that connecting the anterior helices and the posterior helices is called the palatal bridge. The free wire ends that are usually adapted close to the premolar teeth are called the outer arms. The outer arms are soldered to the molar bands.

expansion ‘levels in the prernolar and molar regions. It can be activated prior to cementation of the bands by stretching the molar bands apart or in the mouth with the use of a three-prong plier. When the anterior bridge is adjusted the molar expansion is produced
and when the palatal bridges are activated, the premolar and canine region gets expanded

Ni-Ti Expander :

Latest series of expanders are the Ni-Ti expander these make use of high flexibility of the alloy to produce gentle expansion 300- 350 gm.

Usually used in cleft cases.

Schwarz appliance :

*Horse shoe removable appliance that fits on the lingual border of the mandible

*Has an expansion screw in the midline and retained by ball clasp.

Extraction :

DIFFERENT EXTRACTION PROCEDURES

 
• Balancing extractions

• Compensating extractions

• Phased extractions

• Enforced extractions

• Wilkinson extractions

• Therapeutic extractions

Balancing extractions:

Balancing extractions may be defined as the removal of a tooth on the opposite side of the same arch (although not necessarily the antimere) in order to preserve symmetry .

Compensating Extractions :

Removal of the equivalent tooth in the opposing arch
tomaintain buccal occlusion. In some Class I crowding
cases, it is necessary to extract in both the arches to
maintain lateral symmetry. Compensating extractions
preserve interarch relationship by allowing the
posterior teeth to drift forward together.
Enforced Extractions:

These extractions are carried out because they are necessary as in the case of grossly decayed teeth, poor periodontal status, fractured tooth, impacted tooth, etc

Therapeutic Extractions :

These are extractions carried out for the purpose of treatment.

Wilkinson Extraction :

Wilkinson advocated extraction of all the four first permanent molars between the age of 8½ and 9 years. The basis for such extractions is the fact that first molars are highly susceptible. caries. The other benefits of extracting first molars at an early age are:
To avoid third molar impactions by providing additional space for their eruption.

To reduce crowding in the arch However, Wilkinson’s extractions are not usually carried out because of various drawbacks. first molar extraction offers limited space for crowding correction, adjacent teeth tip into the extraction space and the principal anchor unit for orthodontic appliances is lost.

Teeth that tend to be Extracted :

Incisors:

Maxillary incisors rarely extracted :

Indications for maxillary incisor extraction :

i. Unfavorably impacted maxillary incisors.

ii. Buccally or lingually blocked out lateral incisor with good contact between central incisor and canines.

iii. If a lateral incisor is crowded in linguo-occlusion with its apex palatally displaced and if the canine is erupting in a forward position and is upright or distally inclined, lateral incisor extraction is indicated (Pig. 21.9A).

iv. Grossly carious incisor that cannot be restored.
v. Trauma/irreparable damage to incisors by fracture.

Mandibular incisors :

a. When one incisor is completely excluded from the arch and there are satisfactory approximal contacts between other incisors (Figs 2L9B and 21.9C).
b. Poor prognosis as in case of trauma, caries, bone loss, etc.

c. Severely malpositioned incisor.

d, Lower canines are severely inclined distally and lower incisors are fanned—it is very difficult to correct this condition by extractions further back

Canine :

Canines are rarely extracted  flatting  of the face , alter the facial balance & change In facial expression .

Indication:

·      Mandibular canine may be extracted when it is
likely to be very difficult to align, e.g4 when it is excluded from the arch and the apex is severely
malpositioned or when it is unfavorably impacted.

• When maxillary canine is completely excluded from the arch and approximal contact between lateral incisor and first premolar is good, extraction of the canine may be considered .

First premolar :

It is the tooth most commonly extracted as part of orthodontic therapy especially for the relief of crowding because:

• It is positioned near the center of each quadrant of the arch and is the Sore near the site of crowding, La the pace gained by their extraction can be utilized for correction both in the anterior and posterior region.

• First premolar extraction is the least likely to upset molar occlusion and is the best alternative to maintain vertical dimension.

• The contact between the canine and second premolar is satisfactory

• First premolar extraction leaves behind a posterior segment that offers adequate anchorage for retraction of the 6 anterior teeth.

Second premolar :

Indications for Extraction :

1. When second premolar is completely excluded from the arch following forwards drift of first molar after early loss of deciduous second molar.

2. Second premolar extraction is preferred in mild anterior crowding cases as space closure and vertical control is easier after anterior alignment. The presence of first premolar anterior to extraction site strengthens the anterior anchorage, thereby facilitating closure from behind.

3. Second premolar extraction is preferred when one wishes to maintain soft tissue profile and esthetics.

4. Unfavorably impacted second premolars.

5. Grossly carious or periodontally compromised second premolar (Fig. 2L9D).

6. In open bite cases second premolar is preferred for extraction as it encourages deepening of the bite.