Alignment and leveling

Prepared byDr.Ali Mohammed alsayani

Alignment and leveling

Supervised byDr.Ahmad Altarawneh

Dr.Raed Alrbtah

Outline of the lecture • Definition of alignment and leveling • Goals of the first stage of treatment • Ideal Properties for initial alignment• Wire used in alignment and leveling • Anchorage control in alignment and leveling• Several important consequences for orthodontic

mechanotherapy• Alignment of Symmetric Crowding• Alignment in Premolar Extraction Situations• Alignment in Non extraction Situations• Cross bite correction • Impacted or Unerupted Teeth• Diastema Closure • Leveling

Alignment • Definition:- The arrangement of the teeth in relation to their

supporting bone or alveolar process, adjacent teeth, and opposing dentition.

leveling

• Definition:- Is the process in which the incisal edges of the

anterior teeth and the buccal cusps of the posterior teeth are placed on the same horizontal level.

• Bring the teeth into alignment.• Control the anteroposterior position of incisors.• Control width and the form of the dental arches.

Goals of the first stage of treatment

•Correct vertical discrepancies by leveling out the arches by:-I. Elongation of posterior teeth.II. Intrusion of incisors.III. Combination of the two.

Ideal Properties for initial alignment arch wire

• Excellent strength and springiness. • Long range of action. • Low stiffness.• Good formability.• Ideal shape memory.• Ideal super elasticity.• low friction.• Good esthetic.

Wires used in alignment and leveling

• Australian stainless steel wires. • Titanium alloys:-

Nickle titanium alloy Copper Nickle Titanium alloy

• Coaxial wires. • Braided / Twisted wires.• Composite plastics/optical glass.

Australian stainless steel wires • Advantages:- high resiliency. Low coast. Resist corrosion. Good formability. Can be soldered and welded. Disadvantages :- High stiffness. Low springiness. High modulus of elasticity. Uses :- Mild crowding cases. Displaced teeth.

• Special plus is the best one we can used in alignment and leveling.

It comes in different resiliencies:-

1. Regular with white label2. Regular plus with green label3. Special grade with black label4. Special plus with orange label5. Premium with blue label 6. Premium plus with blue label7. Supreme with lavender label

Titanium alloy wire Nickle Titanium alloy (45%Ti, 53%Ni, 2%Co) Martinsitic stabilized alloye.g Nitinol was invented in 1960. Austenitic active alloy (superelastic)e.g Sentalloy/ Chinese NiTi (Brustone) Martinsitic active alloy (thermodynamic)e.g Neo-sentalloy Advantages:- High springiness. Light constant force. Low stiffness. High shape memory. High elastic limit.

Copper Nickle –titanium alloy Advantages :-• The addition of copper to nickel titanium alloys

increases strength, reduces hysteresis, control transition temperature range, reduces friction and modified shape memory.

• Reduce patient discomfort.• Reduce potential for root resorption. Uses :-• Allow engagement of severely malposed teeth.• Ideally for periodontal compromised cases.

Coaxial wires• Combining of two or more strands of a small stainless steel.• Advantages:- Can withstand the load so they are able and used for

aligning archwires. Low friction. Low cost. Flexible.

Braided/ Twisted wires• Very small diameter S.S wire can be braided or twisted together

by the manufacturer to form wires. Advantages :-• Very flexible.• Delivers extremely light forces.• Full engagement of the arch wire at an early stage.• Available in round and rectangular shapes .• Low cost.

Composite plastics/optical glass

Optiflex is a composite structure formed by top coating optical glass fibers.

Advantages:-Esthetic .Stain resistance. provide light continues forces for initial alignment. Very flexible. Can be used with any bracket system.

SIZE OF THE WIRES• Changing the diameter/ length of a wire greatly

affects its properties for initial aligning and leveling.• When the diameter of wire is doubled:1. The strength increases by 8 times.2. The springiness decreases by 16 times.3. Range decrease by half.• When the length of the wire is increased:1. The strength decreased by 2 times.2. The springiness increased by 8 times.3. Range increased by 4 times.

Anchorage control in alignment and leveling

• BENNET and MC LAUGHLIN emphases the need to consider anchorage in all the three plane of space.

1. Horizontal plane. 2. Vertical plane. 3. Transverse plane.

Horizontal anchorage

• Anchorage control means limiting the mesial movement of the posterior segments while encouraging distal movement of the anterior segments.

• When the posterior mesialize and the anterior procline, anchorage is being lost in the horizontal plane.

BEND BACKS

• Bending the arch wire immediately behind the most distally banded posterior tooth is called cinching.

• It minimize forward tipping of incisors.

Vertical anchorage

• Vertical anchorage control involve the limitation of the vertical skeletal and dental development in the posterior segments and the limitation of the vertical eruption of (or) even intrusion of the anterior segments.

Transverse (Lateral) anchorage

• Control It comprises maintenance of expansion procedure, primarily in the upper arch, and the avoidance of tipping (or) extrusion of posterior teeth during expansion.

Roller coaster effect

• Elastic force were greater than the leveling force of the arch wire, there was tendency for anterior teeth to tip and rotate distally, and increasing the curve of spee, deepening the bite.

Several important consequences for orthodontic mechanotherapy :

• Initial archwires for alignment should provide light, continuous force to produce the most efficient tipping tooth movement.

• To bring teeth into alignment, a combination of labiolingual and mesiodistal tipping guided by an arch wire is needed, but root movement usually is not.

• Round arch wires should be used while rectangular archwires should be avoided.

• The archwires should be able to move freely within the brackets, at least 2 mil clearance between the arch wire and the bracket is needed.

• The largest initial arch wire that should be used with an 18-slot edgewise bracket is 16 mil, and 14 mil and With the 22-slot bracket, a 16mil or 18mil.

• If only one tooth is crowded out of line a rigid wire is needed and an auxiliary wire should be used to reach the malaligned tooth.

Key points during alignment and leveling • Forces should be kept as light as possible.• Sagittal, vertical and lateral anchorage need

should be identified for each case.• Lacebacks and bend backs to be used in the

initial stages to avoid unwanted tooth movement.

• Posterior segment should be supported with headgears / TPA in maximum anchorage cases.

Alignment of Symmetric Crowding

• The flat load-deflection curve of superelastic NiTi makes it ideal for initial alignment when the degree of crowding is similar on the two sides of the arch.

• The extreme springiness of superelastic wires is not a totally unmixed blessing. When these wires are tied into a malocclusion, they have a tendency to "travel" around the arch as the patient chews, especially if function is mostly on one side.

To open space for teeth that crowded out of arch there are two ways

• Use crimped stop on the wire just in front of molar tube

Use of coil spring to open space Use of open coil spring in the anterior or posterior

segments to create space for blocked out teeth . Open coil springs should not be used until 0. 018 or 0.020

round wires are in place.

Alignment in Premolar Extraction Situations  

• In patients with severe crowding of anterior teeth, it is necessary to retract the canines into premolar extraction sites to gain enough space to align the incisors.

• If maximum anchorage is needed (we but bone screw on the alveolus).

• In less extreme but still sever crowding(coil spring from the first molar to tip canine distally).

• When this is done, the arch wire preformed to have an exaggerated reverse curve of spee, to limit forward tipping of the molars.

Use of laceback in extraction cases:

• To control mesial movement of the canines during alignment and leveling, This prevents incisor extrusion during these stages of treatment.

• To retract canines in cases with labial segment crowding during alignment and leveling.

• protection of flexible archwires in extraction spaces.

• centerline correction by unilateral canine retraction in one or both arches.

Alignment in Nonextraction Situations • Alignment in nonextraction cases requires increasing

arch length, moving the incisors further from the molars.

• In this circumstance, just tying a superelastic wire into the bracket slots is ineffective.

• Use crimp a stop on the wire at the molar tube (this type of arch expansion has the potential to carry the incisors facially).

• An alternative is to bypass the brackets on teeth that are crowded lingually.

Cross bite correction

• Individual teeth displaced Into anterior cross bite. • Correction of the cross bite requires first opening

enough space, then bringing the displaced tooth or teeth across the occlusion into proper position.

• Occlusal interferences can make this difficult, the patient may tend to bite brackets off the displaced teeth.

• It may be necessary to use a bite plate temporarily to separate the posterior teeth and create the vertical space needed to allow the teeth to move.

Correction of Dental Posterior Cross bite

1) Heavy labial expansion arch.

2) An expansion palatal arch.

3) Cross elastics.

Transverse Maxillary Expansion by Opening the Midpalatal Suture

• It is relatively easy to widen the maxilla by opening the Midpalatal suture before and during adolescence, but this becomes progressively more difficult as patients become older.

• Separation of the suture should be the first step in treatment, before either extraction or alignment.

Impacted or Unerupted Teeth • Bringing an impacted or unerupted tooth into

the arch creates a set of special problems during alignment.

• The most frequent impaction is a maxillary canine or canines, but it is occasionally necessary to bring other unerupted teeth into the arch.

The problems in dealing with an unerupted tooth fall into three categories

(1) surgical exposure. (2) attachment to the tooth. (3) orthodontic mechanics to bring the tooth

into the arch.

Surgical Procedures

• Two basic types:- 1. Closed method. 2. Open method. • According to Johnston, Gaulis & Joho:- For labially impacted tooth: Closed method

indicated . For palatally impacted tooth : Open method is

indicated .

Method of attachment

1. Lasso technique.

2. Threaded posts.

3. Bonded brackets/ button.

Mode of Traction

1. Ligature wire.

2. Elastomeric chain.

3. K9 spring.

4. Elastic thread.

Diastema Closure

• A maxillary midline diastema is often complicated by the insertion of the labial frenum into a notch in the alveolar bone.

• It is better to align the teeth before frenectomy.

Leveling • leveling can be accomplished with continuous

archwires, simply by placing an exaggerated curve of Spee in the maxillary archwire and a reverse curve of Spee in the mandibular archwire.

Deep Overbite• Deep overbite can be divided into two types. 1. True deep bite:- which is mostly due to the infra eruption of posterior teeth. 2. Pseudo deep bite:- Is due to the supra eruption of anterior teeth.

Advantages:-• A long range of action.• Constant direction of action.• More easily estimated biomechanical effects.• Ability to use wires in the same arch.• Avoidance of some unwanted effects of reciprocal forces.• Avoidance of frictional forces. Disadvantages:-• Complexity of wire fabrication.• Poorer control of overall arch form.• Less ‘fail-safe’ effect.

Segmented archwire

Advantages:-• More rapid relative incisor intrusion.• Range of action of the archwire.• Slightly greater incisor intrusion. Disadvantages :-• Left active until over-correction of the overbite.• Greater relative extrusion of the canines.• Second arch leveling phase may be required.

Sectional archwire

Auxiliary archwire mechanics

Indications:-• When the incisors are upright, the canines

distally angulated.• The combination of a deep overbite and

gingivally placed canines.• A very gummy smile cases.

Rocking chair Ni-Ti wires Advantages/indications :-• Non-extraction arches .• Earlier engagement of brackets with a rectangular

wire.• Long range of action.• Anterior open bites cases. Disadvantages:-• Can cause molar rotation and premolar expansion.• Can causes incisor proclination.• Lingual crown torque cannot be placed in the wire.• Asymmetric bite opening sometimes occurs.

Treatment of deep over bite

• Extrusion or Uprighting of posterior teeth.• Increasing the inclination of upper and lower

anteriors.• True intrusion of upper and lower anteriors.• Combination of two or more of the above

procedures.

Extrusion or Uprighting of posterior teeth

• Indication:- Patients with a horizontal growth pattern. Growing individuals . True deep overbite cases.

Proclination of upper and lower anteriors

• This can be done only if the soft tissue profile permits it or in cases with retroclined anteriors.

True intrusion of upper and lower anteriors

• Bite opening by true intrusion although can be used in both grown and growing individuals, it is effective in growing individuals.

• True intrusion of incisors is indicated in cases of pseudo deep bite where the incisors are supra erupted.

• Methods:-– Utility arches. – Burstone Intrusion arches. – Three piece intrusive arch.

Utility Arches

• It is a complete arch extending across both buccal segments, the utility arch engages only the two molars and four incisors.

• It is commonly known as 2 x 4 appliance (Two by Four appliance).

Types of utility arch

1. Passive utility arch 2. Intrusion utility arch 3. Retrusion utility arch 4. Protrusion utility arch

Passive utility arch can be used for stabilization (or) as a space maintainer It is ideal in the mixed dentition as it permits the eruption of canine and premolars.

Burstone Intrusion arches• Originally proposed by Burstone, these springs are

made of 0.017” x 0.025” TMA wire. • The upper and lower arches have to be leveled and

aligned and a rigid stainless steel wire, preferably of 0.017” x 0.025” dimension should be engaged.

• The anchor molars are reinforced with a TPA in the upper and a lingual holding arch in the lower arch.

Three piece intrusive arch

It consists of the following parts:- • The posterior anchorage unit.• The anterior segment with posterior extension.• Intrusion cantilevers.

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and ion-implanted NiTi arch wires for initial alignment. Clin Orthod Res 1:12-19, 1998.• Localizing ectopic maxillary canines-horizontal or vertical parallax? Eur J Orthod 25:585-589,

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Orthod Dentofac Orthop 100:494-512, 1991. • Silleul MP, Jordan L. Torsional properties of NiTi and Cu-NiTi wires: The effect of temperature

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Thank you