36.在下列何種情況下，絕不考慮實施序列性拔牙（serial extraction）？
(A)嚴重擁擠型第一類咬合異常
(B)牙弓周長不足小於2 mm
(C)前牙過度擁擠，且乳犬齒過早喪失
(D)側門齒阻生或移位，且中線偏移

Criteria of Serial Extraction Patient(Indications)n

 The fundamental arch relationship should be normal (Class I skeletal pattern), the essential elements of the stomatognathic system are in balance, so it is typically indicated in Class I malocclusions.

 Severe arch length deficiency as compared tontooth material is the most importantnindication for serial extraction. There shouldnbe a large arch perimeter deficiency of 10mmnor more (i.e. 5mm or more per quadrant).nThis can be found as a rotation, displacementnor overlapping of incisors.

n The patient should be in early mixedndentition, i.e. Between 8 to 9 years of agenand the incisor crowded.n

 There should be normal or reduce overbitenand all the teeth should be present onnradiograph and in good position to erupt.n

Contraindicationsn

1. Class II and Class III malocclusion withnskeletal abnormalities. It is unwise to startnserial extraction in a child who has a skeletalnproblem, because the closure of extractionnspaces would be affected by how the skeletalnproblem was being treated.n

2. If the initial discrepancy is smaller, tooth sizenarch length deficiency < 5 mm per quadrant.nIf the initial arch length discrepancy is small,nmore residual space at the end of treatmentnmust be anticipated.n

3. Spaced dentition.

n4. Unerupted malformed teeth e.g.ndilacerations.n

5. Congenital absence – Anodontia /nOligodontial.n

6. Extensive caries or heavily filled firstnpermanent molars, which cannot benconserved.n

7. Open bite and deep bite, which should bencorrected first.