Class i Type 5

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Class I Type 5Class I Type 5

Definition

Class IClass I

Normal mesiodistal Normal mesiodistal relation of the relation of the mandibular arch to mandibular arch to the maxillary archthe maxillary arch

Mesiobuccal cusp Mesiobuccal cusp of the maxillary 1of the maxillary 1stst permanent molar is permanent molar is occluding in the occluding in the mesiobuccal mesiobuccal groove of the groove of the mandibular 1mandibular 1stst permanent molarpermanent molar

Class IClass IThere is a slight mesial There is a slight mesial stepstep

The profile is straight or The profile is straight or slightly convex slightly convex

The problem is dental The problem is dental in origin in origin

Neutrocclusion Neutrocclusion (Lischer’s classification)(Lischer’s classification)

Class IClass I

Type 5Type 5

Classified by Classified by Dewey-Anderson Dewey-Anderson as a condition as a condition where there is where there is drifting of molar, drifting of molar, resulting from resulting from premature loss of premature loss of teeth.teeth.

Definition

Causes

CausesCauses

1.1. Premature loss of deciduous second Premature loss of deciduous second molarsmolars

2.2. Reduced mesiodistal dimension of Reduced mesiodistal dimension of deciduous molars due to extensive deciduous molars due to extensive caries lesionscaries lesions

Premature Loss of Premature Loss of Mandibular 2Mandibular 2ndnd Deciduous Deciduous

MolarMolar(Neutrocclusion)(Neutrocclusion)

The maxillary The maxillary 22ndnd deciduous deciduous molar can molar can overerupt and overerupt and thereby obstruct thereby obstruct the migration of the migration of the mandibular 1the mandibular 1stst permanent molar. permanent molar.

Premature Loss of Premature Loss of Maxillary 2Maxillary 2ndnd Deciduous Molar Deciduous Molar

(Neutrocclusion)(Neutrocclusion)The mand 2The mand 2ndnd

deciduous molar has deciduous molar has a broader crown a broader crown than its antagonist. than its antagonist. As a result it As a result it occludes with two occludes with two teeth and when the teeth and when the max 2max 2ndnd molar is lost, molar is lost, the mand molar is the mand molar is still in occlusion with still in occlusion with the 1the 1stst deciduous deciduous molar in the maxilla.molar in the maxilla.

Premature Loss of Premature Loss of Maxillary 2Maxillary 2ndnd Deciduous Molar Deciduous Molar

(Neutrocclusion)(Neutrocclusion)

In this case of In this case of Class I Type 5, the Class I Type 5, the mandibular teeth mandibular teeth are not distally are not distally positioned, but the positioned, but the maxillary teeth maxillary teeth have migrated have migrated mesially.mesially.

Class I Type 5Class I Type 5

Class I Type 5 gives Class I Type 5 gives the appearance of a the appearance of a Class II or Class II or distocclusion, if the distocclusion, if the relationship of the relationship of the cusps of the cusps of the maxillary and maxillary and mandibular molars mandibular molars is the only factor is the only factor considered and considered and studied. studied.

In here, a frequent In here, a frequent error in judgment error in judgment occurs in diagnosis.occurs in diagnosis.

Premature Loss of Premature Loss of 22ndnd Deciduous Molars Deciduous Molars

(Neutrocclusion)(Neutrocclusion)The 1The 1stst molars molars

in both jaws migrate in both jaws migrate mesially. The max mesially. The max molar does that to a molar does that to a greater degree. The greater degree. The movement of the movement of the mand 1mand 1stst molar molar frequently takes frequently takes place in association place in association with a certain degree with a certain degree of mesiolingual of mesiolingual rotation.rotation.

MESIAL SHIFTMESIAL SHIFT

Physiologic movement of the tooth Physiologic movement of the tooth

MESIAL DRIFTMESIAL DRIFT

Caused by local factors, that could Caused by local factors, that could

lead to malocclusion lead to malocclusion

Mesial DriftMesial Drift

Mesial drift Mesial drift of the first of the first permanent permanent molars involves molars involves three separate three separate kinds of tooth kinds of tooth movements:movements:

1.1. mesial crown mesial crown tippingtipping

2.2. rotationrotation3.3. translation translation

Mesial Crown TippingMesial Crown Tipping

Mesial DriftMesial Drift

RotationRotation TranslationTranslation

Modes of Mesial MovementModes of Mesial Movement

There are distinct There are distinct differences in the differences in the mode of mesial mode of mesial movement between movement between the upper and lower the upper and lower first molars caused first molars caused by variations in the by variations in the

1.1. crown shapecrown shape

2.2. number of rootsnumber of roots

3.3. occlusal occlusal relationshipsrelationships

Crown ShapeCrown Shape

Number of RootsNumber of Roots

Occlusal RelationshipOcclusal Relationship

Maxillary First Permanent Maxillary First Permanent MolarMolar

Quickly tips mesially Quickly tips mesially with the loss of with the loss of crown substance of crown substance of the maxillary 2the maxillary 2ndnd primary molars. primary molars.

Mesial tipping causes Mesial tipping causes the distobuccal cusp the distobuccal cusp to become more to become more prominent occlusally. prominent occlusally.

The large lingual The large lingual root of the root of the maxillary 1maxillary 1stst permanent molar permanent molar causes the rotation causes the rotation of the crown with of the crown with mesial tipping. mesial tipping.

Maxillary First Permanent Maxillary First Permanent MolarMolar

If 2If 2ndnd primary molar primary molar is lost prior to the is lost prior to the eruption of the 1eruption of the 1stst permanent molar, permanent molar, translation of the translation of the first permanent first permanent molar during molar during eruption may be eruption may be seen. seen.

Mandibular 1Mandibular 1stst Permanent Permanent MolarMolar

Display mesial Display mesial tipping, crown tipping, crown rotation, and rotation, and translation as well translation as well but they are more but they are more likely to show likely to show lingual tipping lingual tipping during mesial during mesial movement. movement.

The lingual tipping The lingual tipping is caused by the is caused by the absence of a lingual absence of a lingual root and the fact root and the fact that occlusal that occlusal function occurs function occurs buccally to the buccally to the center mass of the center mass of the lower molar, a lower molar, a condition aggravated condition aggravated as the first molar as the first molar drifts mesially.drifts mesially.

Mandibular 1Mandibular 1stst Permanent Permanent MolarMolar

Definition

Causes

Treatment

Objectives of TreatmentObjectives of Treatment

Facilitate a more Facilitate a more conservative, ideal conservative, ideal restoration.restoration.

Eliminate plaque-Eliminate plaque-forming areas.forming areas.

Improve the Improve the alveolar ridge alveolar ridge contour.contour.

Improve crown to Improve crown to root ratio.root ratio.

Re-establish long Re-establish long axis force loading axis force loading of the teeth.of the teeth.

TreatmentTreatment

1.1. Distalize permanent first molars Distalize permanent first molars using space regainers.using space regainers.

2.2. Restore proximal surfaces of Restore proximal surfaces of carious deciduous molars to restore carious deciduous molars to restore mesiodistal dimension of adjacent mesiodistal dimension of adjacent teeth.teeth.

Space RegainersSpace Regainers

Space regainers Space regainers are appliances are appliances used for regaining used for regaining space lost in the space lost in the line of the dental line of the dental arch. arch.

They are used to They are used to tip to upright tip to upright positions those positions those teeth that have teeth that have drifted after other drifted after other teeth have been teeth have been lostlost


Space regainers Space regainers find their greatest find their greatest use in the mixed use in the mixed dentition after dentition after premature loss of premature loss of primary molars in primary molars in positioning positioning permanent teeth. permanent teeth.

The space regainers The space regainers are not to be used are not to be used for creating space in for creating space in the line of arch that the line of arch that was never there. was never there.

Regaining what was Regaining what was once there is entirely once there is entirely different from different from creating that which creating that which was never there.was never there.

Reduction in Reduction in available dental arch available dental arch length resulting from length resulting from migration after migration after premature loss of premature loss of deciduous molars deciduous molars can sometimes be can sometimes be regained, at least in regained, at least in part.part.

The conditions The conditions are more favorable are more favorable in the mandible than in the mandible than in the maxilla; in the maxilla; regaining space regaining space seldom occurs in the seldom occurs in the latter. latter.

Factors to Factors to Consider in Consider in Using Space Using Space Regainers:Regainers:

1.1. Crown ShapeCrown Shape

2.2. Bone StructureBone Structure

3.3. Jaw FormJaw Form

The lack of space The lack of space regaining in the maxilla regaining in the maxilla is partly attributable to is partly attributable to the the rhombic formrhombic form of the of the maxillary 1maxillary 1stst permanent permanent molar. molar.

The The spacespace between the 1between the 1stst premolar premolar that has just emerged that has just emerged and the rotated 1and the rotated 1stst permanent molar is permanent molar is trapezoidaltrapezoidal, yet the , yet the succeeding tooth is more succeeding tooth is more rectangularrectangular..

In the mandible, In the mandible, the 1the 1stst permanent permanent molar that have molar that have migrated mesially migrated mesially can can move distally with the move distally with the eruption and eruption and emergence of the 2emergence of the 2ndnd premolarspremolars. Likewise, . Likewise, 11stst premolars that premolars that have drifted distally have drifted distally can move mesially.can move mesially.

In the maxilla, In the maxilla, this phenomenon is this phenomenon is seldom seen.seldom seen.

It is not only on It is not only on mechanical grounds that mechanical grounds that a mandibular 2a mandibular 2ndnd premolar can, on premolar can, on eruption and emergence, eruption and emergence, regain the space regain the space originally intended for it. originally intended for it.

There are also There are also more favorable more favorable conditions of bone conditions of bone structure and of jaw form structure and of jaw form in the mandible than in in the mandible than in the maxilla. the maxilla.

MAXILLAMAXILLA

The trapezoid area The trapezoid area previously described previously described contains bone that is not contains bone that is not compact but compact but cancellouscancellous. .

MANDIBLEMANDIBLE

The corresponding The corresponding bone structures bone structures more more densedense, and the , and the limited limited buccolingual dimensionbuccolingual dimension of the jawbone forms an of the jawbone forms an additional restriction for additional restriction for escape.escape.

Types of Space RegainersTypes of Space Regainers

1.1. Split-saddle Acrylic Space RegainerSplit-saddle Acrylic Space Regainer

2.2. Slingshot RegainerSlingshot Regainer

3.3. Recurved Helical SpringRecurved Helical Spring

4.4. Sliding Yoke RegainerSliding Yoke Regainer

5.5. Expansion Screw Space RegainerExpansion Screw Space Regainer

Split-Saddle Acrylic Split-Saddle Acrylic Space RegainerSpace Regainer

Slingshot RegainerSlingshot Regainer

Recurved Helical SpringRecurved Helical Spring

Sliding Yoke RegainerSliding Yoke Regainer

Expansion Screw Expansion Screw Space RegainerSpace Regainer


Do not overextend the space Do not overextend the space regaining appliance. regaining appliance.

Space regaining appliances are Space regaining appliances are intended to be used solely for intended to be used solely for recovering space that once was recovering space that once was therethere. Space regaining is not space . Space regaining is not space creating.creating.

Space Regainers Space Regainers

for Extensive Loss of Arch for Extensive Loss of Arch LengthLength

Amount to Amount to be be

RegainedRegainedMandibleMandible MaxillaMaxilla

0-2 mm0-2 mmHelical Spring, Helical Spring,

Split-SaddleSplit-SaddleSplit-Saddle, Split-Saddle, Helical SpringHelical Spring

2-4 mm2-4 mmSlingshot, Slingshot,

Split-SaddleSplit-SaddleSplit-Saddle,Split-Saddle,

Sliding YokeSliding Yoke

>4 mm>4 mm -- Extraoral Extraoral ForceForce


The The timingtiming of space regaining is of space regaining is important. Since the position and stage important. Since the position and stage development of the 2development of the 2ndnd permanent molar permanent molar often is a limiting factor. often is a limiting factor.

When the simpler space regaining When the simpler space regaining appliances cannot complete the task, one appliances cannot complete the task, one may resort to may resort to extraoral tractionextraoral traction, but before , but before using extraoral traction, the case should be using extraoral traction, the case should be reassessed completely to make certain that reassessed completely to make certain that the original the original diagnosisdiagnosis still obtains. still obtains.


Do not overextend the space Do not overextend the space regaining appliance. regaining appliance.

Space regaining appliances are Space regaining appliances are intended to be used solely for intended to be used solely for recovering space that once was recovering space that once was therethere. Space regaining is not space . Space regaining is not space creating.creating.


When the loss of perimeter length When the loss of perimeter length is so extensive as to be is so extensive as to be beyond the beyond the scope of the simpler appliancesscope of the simpler appliances, or , or when there is when there is insufficient timeinsufficient time to to recover the space before eruption of recover the space before eruption of the bicuspids and 2the bicuspids and 2ndnd permanent permanent molars, a far more difficult clinical molars, a far more difficult clinical situation obtains and situation obtains and comprehensive comprehensive multibanded appliance therapymultibanded appliance therapy usually usually is indicated.is indicated.

Good day!Good day!

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Class i Type 5