TYPES OF ORTHODONTIC FORCES

Continuous force- active force that decreases little in magnitude betwwen appointments.

  • Light weight appliances
  • Highly flexible appliance components used which are activated at low force level.
  • No interference with biological function and no harm to soft tissues.
  • Direct resorption of bone

Intermittent force- active force that decays to zero before next appointment.

  • High stiffness appliances
  • Twice the force activation for corresponding soft tissue deformation
  • Undermining resorption and corresponding tooth movement.

Interrupted force- inactive for intervals of time between appointments

  • Cyclic, long term magnitude time pattern
  • Heavy forces delivered
  • No force decay

Reference- orthodontics bhalajhi

TYPES OF TOOTH MOVEMENTS

Can be categorized into 3 categories-

  • Pure translation- intrusion and extrusion, bodily movement
  • Pure rotational- torquing and tipping
  • Generalized rotational

1. Tipping- single force applied results into movement of crown in direction of force and movement of root in opposite direction.

A) Controlled tipping- When tooth tips about centre of rotation at apex. Lingual movement of crown with minimal movement of root in opposite direction.

B) Uncontrolled Tipping- when movement of tooth occurs about centre of rotation close to centre of resistance. Crown moves in lingual direction and root in opposite direction.

2.Torquing – reverse tipping characterized by lingual movement of root.

3. Bodily movement- All points on tooth will move equal distance in the direction of applied force. Line of action of force is through centre of resistance.

3. Intrusion- bodily displacement of tooth in apical direction along longitudinal axis of tooth.

4. Extrusion- bodily displacement of tooth in coronal direction along longitudinal axis of tooth.

5. Rotational- labial or lingual movement of tooth around long axis

6. Uprighting- when crowns are tipped in mesiodistal direction roots tipped in opposite direction. Tipping the roots back to get parallel orientation is called uprighting.

Reference- ortho bhalajhi

ADAMS CLASP

Clasps are the retentive components of the removable appliances.

Mode of action-

  • Clasps act by engaging certain areas of teeth called the undercuts.
  • Two types of undercuts are found in natural dentition
  • Buccal and lingual cervical
  • Mesial and distal proximal
  • Adams clasp engages the mesial and distal proximal undercuts.

Adams clasp also called as universal clasp, liverpool clasp and modified arrowhead clasp.

Parts of adams clasp-

  • Two arrowheads
  • Bridge
  • Two retentive arms

Advantages of adams clasp-

  • Rigid and offers excellent retention
  • Fabricated on deciduous and permanent dentition
  • Can be fabricated on fully or partially erupted tooth
  • Can be used on molars, premolars and incisors.
  • Small and occupies minimum space
  • Can be modified in many ways.
  • Universal pliers can be used for fabricating.

Modifications of adams clasp-

  • Adams with single arrowhead
  • Adams with J hook
  • Adams with incorporated helix
  • Adams with additional arrowhead
  • Adams on incisor and premolars
  • Adams with distal extension

Reference- Bhalajhi 7th edition

STEPS IN FABRICATION OF ADAMS CLASP

Mesial and distal undercuts of the molar are marked on the cast. This distance between these 2 marks would form the length of bridge of Adams.
22 gauge hard round stainless steel wire is used. 90 degree bend is made.
Wire is placed on the model and distance between mesial and distal undercuts is marked on wire.
The other 90 degree is made thus forming bridge of adams clasp
Round beak of universal plier is placed on outer side close to bridge of adams
Wire bent around to form a “U” thus forming the arrowhead
Arrow head is squeezed between the two beaks of pliers to make it as narrow and pointed as possible.
Arrow head is given a 45 degree twist so that arrow head at angle of 45 degree to bridge of adams
Outer arm of arrow head is given a 90 degree bend at a height that is half of arrow head. Done by placing round beak inside arrow head.
Other arrow head is also bent similarly so that the free end of wire rests in embrasure. Wire is bent down and adapted between teeth.
Place a mark beyond palatal side of contact area.
Palatal tag is bent down and is slightly kinked to form step over gingiva. Palatal wire is adapted to be parallel to the plaster.

3 things to be noted after the clasp is placed on tooth:-

  • When viewed from occlusal aspect bridge is parallel to buccal aspect.
  • Bridge to be at 45 degree to long axis of tooth.
  • When viewed from buccal aspect parallel to occlusal surface.

Reference- bhalajhi ortho

Ortho Case 3.3

A 14-year-old male presented with a class I malocclusion on a skeletal class I base with average vertical dimensions complicated by an ectopic and mesially-angulated UR3, crowding of both arches and centre line discrepancies.

What will be the treatment for creating space for canine and correcting central line discrepancies? Which teeth will be extracted? What appliances will be used and what force level should be used during space closure?

To understand this and more, read the pdf attached to the link. I have also tried to explain the case via digital images. I have attached 5 images. Do check it out 🙂

Happy Reading Friends!
LINK: https://drive.google.com/file/d/1cfWNTyZVX7IISDGJvJIZ8rjuXZ3fR2Hd/view?usp=sharing

Ortho Case 3.2

Link: https://drive.google.com/file/d/1htUo39ZpGIdf5XGRcSmcn3RAsYzJEY6k/view?usp=sharing

A 13-year-old female presented with a class I malocclusion on a mild skeletal class II pattern with average vertical dimensions complicated by impaction of the LR5 and an invaginated UL2

What is treatment plan? Which tooth will be extracted? What factors need to be considered when substituting a maxillary canine for a lateral incisor?

I have attached following images for easy read! Happy Reading Friends 🙂