CLASS I MALOCCLUSION

Done by :- Ahmed Salih Abbas

Occlusion Occlusion is the relationship of the maxillary and mandibular teeth

when the jaws are in a fully closed position. Classification of teeth :-• Class I (normal occlusion)•Class I malocclusion•Class II malocclusion•Class III malocclusion

*Prevalence of malocclusion :-

Class I normal occlusion: 30% Class I malocclusion: 50-55% Class II malocclusion: 15% Class III malocclusion < 1% More class II in whites and more class III in Asians. Class III and open bite are more frequent in African than European populations

Causes of orthodontic class I problems :

1. Developmental causes :-The most encountered developmental disturbances are:-Congenitally missing teeth.-Malformed teeth.-Supernumerary teeth.-Impacted teeth.

-Ectopic eruption. 2- Genetic causes :- Genetics play major role for malocclusion when there is discrepancy between size of the jaws & size of teeth.3. Environmental causes:It is caused by injures which has two types:-

1. Birth Injures:It comes under two major categories:Fetal molding (when a limb of the fetus presses another part leading to distortion of that part ).Trauma during birth from usage of forceps .2-Injures throughout life :

Trauma to teeth can lead to development of malocclusion in three ways:Damage to permanent tooth bud when primary tooth is traumatized.Premature loss of primary teeth leading to permanent tooth movement.Direct injury to permanent teeth.

Note :- both dental and skeletal factors are incorporated in class 1 malocclusion.

*Comparison of Mesiodistal Tooth Width between Normal Occlusion and Malocclusion :-

In the malocclusion group the mesiodistal tooth width of the upper and lower central incisors, lower left lateral incisor, and lower first molars were significantly higher than in the normal occlusion group.

DENTAL FEATURES:

Bimaxillary proclination Increased incisal angle Spacing between teeth Normal molar and canine relationship Steep mandibular plane angles

Features of skeletal class I malocclusion:

SKELETAL FEATURES: Harmonious face Straight to convex profile Nothing really abnormal

* Diagnosis :--History-Clinical examination-Study models-RadiographyOPG.Periapical radiographs .Lateral cephalometrics.

Components of CL. I malocclusion

• Crowding: the most significant contributor to malocclusion• Vertical problems: open bites or deep bites• Transverse problem: relatively rare.

** SPACING :- 1-Generalized:Eliminate the cause.2-Microdontia-Eliminate spaces between anteriors,leaving a space between canine and 1st premolar-Prosthesis3-Spacing with proclination:Labial bowElastics with fixed or removable appliance.

Localized spacing with proclination:-Labial bow with finger spring :-

Midline Diastema:--Eliminate cause i.e. high labial frenum attachment.-Removable appliances:-#Finger spring.#Finger spring with labial bow.#Split labial bow.-Fixed appliances:Pin and tube appliance.

CROWDING

Analyze space discrepancy using model analysis. Treatment is planned on the amount of space required. Mild Crowding: If the space discrepancy is up to 4mm: usually resolves without extraction. Proximal stripping Alignment of teeth by labial bow, finger spring. Moderate crowding:If space discrepancy is in the range of 5-9mm, treated without extractions by :--Arch expansion -Molar anchorage or -Enamel reduction.Severe crowding :*Patients with space discrepancy of 10 mm or more:Extract all 1st premolarsRetract canine by canine retractorAlign anteriors by labial bowRetention by Hawley’s retainer.

CROSSBITE

ANTERIOR :-

-Z-spring with posterior bite plane.-Expansion screw with posterior bite plane.

*POSTERIOR :--Single tooth:Cross-elastics-Unilateral:Unilateral expansion screw Functional appliance-Bilateral: # Maxillary expansion is done to relieve cross bite by:# Coffin spring

Quadhelix appliance :-

A patient with his upper right lateral incisor and upper left central incisor in crossbite. B, The lingualinclination of the teeth in crossbite-a favorable condition. C and D, A fixed appliance in the upper arch and a removableacrylic posterior bite block in the lower arch that opened the bite enough to easily move the teeth forward out ofcrossbite. E and F, The occlusion and upper arch after removal of the appliances.

OPEN BITE

ANTERIOR:◦ Eliminate habit

Thumb sucking Tongue thrust Mouth breathing

◦ Skeletal openbite i. during mixed dentition:

Frankel IV or chin cap with high pull headgearii. In permanent dentition,before puberty

Fixed appliance with box elasticsiii. In permanent dentition after puberty:

Surgery◦ If due to supra-erupted posteriors:

Posterior segmental osteotomy

ROTATIONS

ROTATIONS

Single Tooth: Removable Appliance:

Couple force by flapper spring/ double cantilever spring and labial bow

Semi-fixed Appliance: Whip spring High labial bow with soldered ‘T’ spring

Multiple rotations: Treated by fixed appliance Overcorrection is done and retention is given

for atleast 1 year….

ROTATIONS High Labial bow

T spring

BIMAXILLARY PROTRUSION

BIMAXILLARY PROTRUSION

Extract all 1st premolars, or 1st molars.

Treatment depends on angulation of canine:

Distally inclined canine: Retract canine and align incisors using retainers

Mesially inclined canine: Fixed appliance

BIMAXILLARY PROTRUSION

Before & After Treatment

THANK YOU !!