Arrangement of Teeth in Class 2 Relation

CONTENT: INTRODUCTION FEATURES OF THE CLASS-2

ARRANGEMENT ANTERIOR ARRANGEMENT FOR

CLASS-2 RELATION POSTERIOR ARRANGEMENT FOR

CLASS-2 RELATION CONCLUSION

INTRODUCTION: The overjet increases up to 5 mm. The stability of the denture base supported by

such a ridge is a primary concern in the class-2 patient because the lower ridge is already compromised in size, compared with the upper ridge.

In the class-2 relation the lower ridge is smaller & markedly lingual in relation to the upper ridge.

One must not attempt to place the teeth more labially as this may cause instability.

The anterior teeth exhibit a pronounced horizontal overlap when they are arranged properly for esthetics.

The vertical overlap should be kept as small as esthetics and phonetics will allow in order to establish and incisal guidance as shallow as possible.

Class-2 problems can be due to insufficient growth of the lower jaw, an over growth of the upper jaw, or a commination of the two.

Class-2 problems are treated via growth redirection to bring the upper and lower teeth and jaw into harmony.

FEATURES OF THE CLASS-2 ARRANGEMENT:

A pronounced horizontal overlap. Canine relation more posterior and lingual

when compared to that of class-2 relationship. Because of the reduced space on the lower

ridge ,the premolars may be ground mesiodistally or one premolar on either side may be removed entirely.

Nonanatomic teeth or teeth with shallow inclines are selected to reduce the stress on the weaker lower ridge.

The buccal cusp of the upper and lower premolars are flattened to provide a stable centric occlusal contact.

The molars are not affected much usually and the normal functional and nonfunctional cusp relations are maintained.

ANTERIOR ARRANGEMENT OF CLASS-2 RELATION MAXILLARY TEETH ARRANGEMENT: CENTRAL INCISOR: Slightly mesially inclined so that the central

incisors meet at midline at their incisal 1/3 rd. Slightly labially inclined.incisal edge is placed

more labially than neck. Incisal edge touches the horizontal plane. Distal end of the tooth should be rotated to

follow the contour.

LATERAL INCISOR: The incisal 1/3 rd is more mesially inclined. It is more mesially inclined than central

incisor with neck depressed. Incisal edge should be 1 mm above

horizontal plane. CANINE: It is vertically placed. Tip of the canine should touch the

horizontal plane. Tooth angle should be 45 angle.

MANDIBULAR TEETH ARRANGEMENT: CENTRAL INCISOR: The long axis is parallel to the vertical

axis when viewed from front and sloped slightly labially.

The incisal edge is 1 mm above the horizontal plane.

LATERAL INCISOR: The long axis is parallel to the vertical

axis when viewed from the side but not as steep as the central incisor.

Incisal edge is 1 mm above the horizontal plane.

CANINE: The long axis is inclined very slightly

towards the midline when viewed from front.

It is also slightly inclined lingually when viewed from the side.

Its tip is slightly more than 1 mm above its horizontal plane.

POSTERIOR ARRANGEMENT OF CLASS-2 RELATION: SETTING THE UPPER POSTERIOR TEETH: The first premolar is set in an esthetically

harmonious arch position with enough lingual tilt to provide stable contact with the lower first premolar.

The amount of buccal overlap is usually considerable.

The excursion of the mandible makes a stable contact possible on the working side.

The second premolar is similarly set with lingual tilt but does not have as much buccal overlap.

The first and second molars are set to occlude with typical nonanatomic tooth contacts as previously described.

SETTING THE LOWER POSTERIOR TEETH: All of the criteria that were discussed for

positioning the lower posterior teeth in relation to the lower ridge are applied to this setup.

The only variation is the angulation of the posterior teeth, which controls the angulation of the flat occlusal surface of the nonanatomic teeth.

All of the posterior teeth can be set with a buccal tilt.

A combination of level balance and occlusal balance is possible by incorporating both a buccal tilt and a lingual tilt in the posterior arrangement.

This revised occlusal scheme was described by pleasure.

The lever balance obtained in the premolar area is nearly at the anteroposterior center of the denture foundation.

It is also where the class-2 patient functions during light to heavy intermediate chewing.

The first molar occlusal surface directs the force of chewing directly to the ridge without unfavorable lever activity when positioned over the ridge crest.

CONCLUSION: The ridge relationship apparent on the articulator for

this type of case appears to present difficult problems for the arrangement of the posterior teeth.

It is not possible to successfully manage these problems with a conventional setup because the teeth would have to be placed in unnatural positions.

The atypical arrangement described provides for a natural position for the posterior teeth it employs a lingual contact concept of occlusion,it establishes lever balance favorable to the inherent lower denture problem,and it allows for the development of a balanced occlusion.

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