SKELETAL CLASS TWO DENTAL DIVISION ONE - EXTRACTION CASE.
Cephalomatric analysis:
Sagittal values -ANB more than 3 degrees.
Vertical values - will determine the type of pull for the headgear.
Dental : protrusion of anterior dentition.
Arch length discrepancy : moderate to severe crowding
( unable to treat non-extraction).
Age : Growing patient.
TREATMENT PLAN
Skeletal problems:
· objective- to correct from skeletal class ll to class l
· treatment plan : the use of headgears as an orthopedic appliance. Allow the mandible to grow into class l position.
Dental problems
· objective : to retract the anteriors into the facial bones
Treatment plan:
Extract all four first bicuspids retract anteriors into facial bones.
MAXILLARY ARCH.
· Band upper right and left first molars.
· Band upper right and left second bicuspids.
· Attach brackets to all anterior teeth.
(Observe bracket heights).
INITIAL ARCHWIRE.
The initial maxillary archwire is a flexible wire. Use either .0175 or .016 NITI. This helps to unravel the crowding in the anterior region. There is usually more initial crowding in the maxillary arch than in non-extraction cases hence these flexible wires are used for one to three months. The wire is tied down the first month with O rings, subsequent months they are tied with ligature wires. This allows faster leveling and aligning.
The bracket on the upper 1st molar has a 15 degrees rotation. When the NITI wire is placed into the bracket it is will to derotate the molars from a class ll to a class l position.
SECOND APPOINTMENT.
(One month later).
HEAD GEAR ISSUE.
(Read on head gear issue).
Guideline for applied force:
Initially 8 oz / 224 grams.
Subsequently 16 oz /448 grams.
First the head gear is activated to 8 oz by stretching the elastic module to the first dimple.
The force of application at the first dimple is about 8 oz or 224 grams. At the next visit usually about four to five weeks later the force is increased to 16 oz or 448 grams this is done by stretching the elastic to the second dimple. The force is now maintained at this level throughout the treatment. At every visit the force applied is checked and accordingly adjusted.
FACEBOW ADJUSTMENT
Use special headgear adjusting pliers.
VERTICAL - to center of lips.
TRANSVERSE - Keep inner bow expanded.
SAGITALLY - Enlarge or constrict adjustment loop.
MOLAR ROTATION - maintain molar rotation by adjusting the distal end of the inner bow.
Outer bow is kept parallel to inner bow and parallel to occlusal plane.
Orthopedic correction:
key to success-
· Growth.
· Cooperation.
· Directional pull.
· Force.
Advantage of orthopedic correction with facebow:
Affects growth in all direction.
Sagittal - cervical pull.
Vertical - high pull.
Transverse - expansion of inner bow.
Guidelines for direction of pull.
If SN - MP is :
1. Below 35 degrees.
The directional pull is cervical.
2. Between 35 and 42 degrees.
The directional pull is combination.
3. Above 42 degrees.
The directional pull is High.
GUIDELINES FOR HOURS WORN PER DAY.
If ANB is:
1. Less than 3 degrees.
Wear 8 hours (nights only).
2. Between 3 to 5 degrees.
Wear 10 hours per day.
3. More than 5 degrees.
Wear 12 hours per day.
Facebow adjustment
· Outer bow around cheeks.
· Molar intrusion
bend outer bow 20 degrees at first molar.
· Unilateral - molar class II.
Bend outer bow on class ll side outward and lengthen stop on inner bow class ll side.
SECONDWIRE CHANGE.
The second wire is .016 SS wire. It is used to continue leveling and eliminating rotation. It is also an excellent wire for retracting the canines.
Check list:
Adapt wire to template.
Bend omega loops.
Wipe in accentuated curve of spee.
Toe in .
Heat treatment.
Tie back.
Adjust headgears
Fabrication of omega loops. ( check previous Blog posting.)
The fabricated .016 round wire is now place into the arch.
Take three unit chain elastic.
Place the first ring around the head gear tube. Do not place it on the hook. Use a hemostat and stretch the third ring of the chain elastic all the way to the cuspid and attach it to the cuspid bracket. Do not engage the middle ring to the bicuspid bracket. You only attach it to the head gear tube and the cuspid. Take regular power O and put it on the biscuspid bracket. This engages the power chain to the bracket. This is a very simple procedure but it is very important to do it the right way. This simple technique will retract the canines very effectively compared to other techniques.
Reasons for cuspid retraction prior to the anterior retraction.
· There is more control over molar anchorage. As only the cuspids are retracted against the bicuspids and molars as opposed to all six anteriors. In retracting all six anterior teeth against four posterior teeth there is a tendency to burn anchorage.
· To get the cuspids into class l position quickly and build the final occlusion around this newly established cuspid position.
There are two important rules to follow.
· Do not change the power chain too often. Change it once every 4 to 5 weeks. If it is changed too often it will move the cuspids too fast and it will get completely of control. Initial tipping will occur and the tooth will not have time to upright and rotate itself back into its normal position after the force of the power chain dissipates.
· Always make sure the .016 round wire remains in the slot as the cuspid is being retracted. If it rotates out which sometimes it does. Take a ligature wire and wrap it around the bracket and re engage the wire into the slot. Place the power chain over the ligature wire. If the wire disengages from the slot of the bracket the cuspid will be totally out of control. It is very important to ensure that the wire is in the slot all the time. When the patient comes in for the appointment and when you remove the old power chain off check and confirm that the wire is in the slot. If it has disengaged and slipped out of the slot, take a ligature wire and tie it back. The wire must not be tied too tight because if it is tied it too tight then the canine will not slide back.
Question: Why do you attach the power chain to the buccal tube and not to the hook?
Answer:
· If attached to the hook it lies to close to the gingival and becomes a food trap causing irritation and gingival tissue swellings.
· The force to the power chain is less if attached to the hook, it is greater if attached to the buccal tubes.
· When warped around the headgear tube the power chain lies on the arch wire all the way to the canine.
It takes about six months to retract the cuspids changing power chain every 4 to 5 weeks.
THIRD WIRE CHANGE. (The closing loop wire).
Take a flexible millimeter ruler and measure from the distal of the lateral incisor to the distal end of the opposite lateral incisor . The obtained measurement gives the size of the closing loop wire to be selected. The loops are place about a millimeter distal to the lateral bracket. The wire size between the loops is 18x25 and the wire size distal to the loop is a reduced wire size 16x22. This unique wire has two different sizes combined in one wire. A full size wire in the anterior region and a reduced size in the posterior section. This wire is taken to the template and adapted to the arch form.
This wire does not have omega loop and it is not toed in. A slight curve of spee is place distal to the loop. The amount of curve of spee wiped into the wire always depends upon the bite. In deep bite case a large curve is placed and in not so deep bite cases a moderate curve is placed into the wire. This curve of spee is place between the loop and the first molar. The wire is cut at an angle from the outside inwards and the end is sharpened with the help of a bur. This helps to thread the rectangular wire into the slot of the molar bracket. After the wire has been place into the slot it is then activated by cinching back with a cinch back pliers. The distal portion of the wire is grasped with the cinch back pliers it is the pulled back to open the loop. In doing so the loop is activated by about a millimeter. While gasping the distal end the wire is twisted to give a 45 degree bend and this prevents the wire from slipping back into the slot. The activation in now repeated on the opposite side. It is advisable to have the patient bite on a cotton roll while this process is being carried out. It is less traumatic and give more control. The anterior teeth are now consolidated with a continuous ligature tie and the posterior teeth are ligated with individual ligature wires.
Removing the wire:
The wire is cut mesial to the molar bracket on both sides. The anterior portion is removed first then the posterior portion that has been cinched back is removed.
QUESTION: When the anterior teeth are retracted with the rectangular wire will the posterior teeth move forward? That is, will you lose anchorage?
Answer: The 15 degree rotation in the molar tube and the use of the headgear will help to reinforce anchorage. This will help to hold the posterior segment while the anterior segment is being retracted.
QUESTION: Do you use head gear every time you retract the anteriors.
ANSWER: No. You only use headgears when you want to ensure anchorage.
QUESTION : Do you have to ligate the posterior segments together?
ANSWER: No, they will not slide forward.
FINISHING WIRE.
Since there is no difference in the arch form between non-extraction and extraction arch forms, the difference being only in the arch length. The finishing arch wire is common for both type of cases. That is the .017 x .025 stainless steel. Omega loops are usually bent into this wire and place just in front of the molar tubes. The omega loop must have an acute angle so that the ligature wire will not slide off when place and tied back to the molar tube.. A slight curve of spee between the omega loop and the cuspid could be wiped in depending upon the amount of deep bite present. Since this wire is a strong wire too much of curve wiped into the wire will open up the bite and get completely out of control Slightly toe in distal to the omega loop. Care is also given not to curve the distal end too much because by this time the molars have quite well rotated so we do not have to toe in the wire a lot. The wire is tied in with ligature wires and tied back at the omega loops. The entire maxillary arch has been consolidated as one unit and the spaces will not open up. This wire is left in position till the end of the treatment. This wire also forms the base for the application of elastics and class ll or class lll mechanics.
MANDIBULAR ARCH.
The mandibular arch is banded and bonded only when a Class l cuspid relationship has been achieved. This is to avoid the impingement of the maxillary cuspid tip upon the mandibular cuspid bracket. It is always advisable to wait for the cuspids to attain class l relationship prior to the commencement of banding and bonding the mandibular arch. Hence maxillary cuspid retraction is carried out completely before mandibular cuspid bracket placement.
The first wire for the mandibular arch is the multi-stranded .0175 or .016 Ni-Ti. Turbo .017 x .025 or D- Rect .017 x .025 which is usually implemented after four to six months of‘ driftodontics’. This very flexible wire needs no adjustment. As torque control to keep the mandibular incisors upright over basal bone is not a major concern you could use the .0175 Respond or .016 Ni-Ti wire. When these wire are used a second initial wire such as .016 stainless steel round wire or an .017 x .025 D-Rect should be used for about 1 to 3 months before utilizing the closing loop wire.
Mandibular Closing loop Wire.
The closing loop wire is the .016 x .22 stainless steel wire designed to the vari-simplex archform.. The purpose of this wire is to close the extraction site. Unlike in the maxillary arch where only the four incisors are retracted, .in the mandibular arch all six anterior teeth are retracted concurrently. The mandibular closing loop like the maxillary closing loop is tear drop in shape. These teardrops are placed distal to the canine brackets.
If the most posterior tooth banded is the first molar the arch wire is place and activated exactly as in the upper arch. The opening loop is activated about 1 mm by pulling the distal end of the wire as it protrudes through the convertible tube and the distal end is now cinched down at about 45 degrees angle to the horizontal. If the second molar is banded and there is sufficient space distal to the second molar then cinching back is done in a similar way as it is done with the first molar. But most of the time there is insufficient space available distal to the second molar for cinching back the wire. In such situation an omega loop is placed in the archwire just distal to the first molar tube. The slot in the convertible tube on the first molar is removed and the tube is now converted into a bracket. This enables us to place the arch wire with the omega loops. The omega loop is now actively tied back to the second molar hook. It is tied in such a way that it opens up a space about 1 mm in the tear drop section of the wire. The closing loop is activated about 1 mm per appointment. If a severe curve of spee is present for the first time when the wire is placed. The archwire is then not activated but it is activated during the subsequent visits. Due to driftodontics in the lower arch the closing loop is used for a shorter period than in the maxillary arch. In very severe crowding case and due to driftodontics the extraction space is virtually self eliminated and a very small space about 1 mm remains. In such situation a .016 stainless steel round wire is placed and a power chain is applied from the first molar to the first molar on the opposite side. This will help to eliminate all spaces and the mandibular arch could then be consolidated.
FINISHING ARCHWIRE.
Once all the space has been closed , the .017 x .025 stainless steel wire is now utilized which is similar to the one used in the upper arch. At this stage in an extraction case when the wire is placed for the first time there is usually a large curve of spee present. It is not advisable to place any reverse curve of spee at this stage. The wire is just left flat for the first time and a couple of visits later the wire is removed and a slight reverse curve of spee is place in the wire. Omega loops are place in the wire and tied back with the help of ligature wires. It is essential to level the mandibular arch completely. When second molars are banded the omega loop are place about I mm mesial to the second molar tubes for tying back. By tipping the omega loop buccaly torque is built into the wire to compensate for the lack of torque in the second molar tubes..
ELASTIC FORCES:
Application of intra oral forces:
1. To align the maxillary dentition to the mandibular dentition to achieve proper occlusion.
2. To correct cross bite and mid line discrepancies.
3. To aid in the settling of the occlusion at the end of treatment.
Elastic forces are only applied when both the arches are in the finishing .017 x.22 stainless steel wires. Exception being only in class III cases where class III elastic are used early in treatment. And in bimaxillary protrusion cases where we need to upright the lower anteriors and retract them early in treatment.
CLASS II ELASTIC.
Attachment. Upper laterals to lower 1st or 2nd molars
force. 1/4 inch 6 oz. (Ram).
1 2 3 4 5 6 7
1 2 3 4 5 6 7
Purpose # 1
CLASS II MALOCCLUSION
When
FINISHING ARCHWIRE.
Time
24 HOURS/DAY.
Purpose #2
SLIP LOWER ANCHORAGE
( Caution do not tip lower anteriors forward).
CLASS III ELASTICS
Attachment
Lower laterals to upper 1st molars.
Force
1/4 inch. 3.5oz. (Fox).
1 2 3 4 5 6 7
1 2 3 4 5 6 7
Purpose # 1
CLASS III MALOCCLUSION.
When:
Throughout treatment.
Time: Dependent upon severity.
Purpose # 2
BIMAXILLARY PROTRUSION
(MAXIMUM ANCHORAGE).
When
WEARING COMBINATION FACEBOW
LOWER CLOSING LOOP ACTIVATED
Time.
72 HOURS, THEN NIGHT ONLY WITH FACEBOW.
Purpose # 3.
PREVENT ADVANCING THE LOWER ANTERIORS IN CROWDED NON EXTRACTION ARCH.
When
Initial archwire in lower arch.
Time
36 HOURS, THEN NIGHT ONLY WITH FACEBOW.
CROSS - BITE ELASTIC.
Where: Buccal of one arch to lingual of another arch.
Force: 3/16 inch. 6 oz (impala)
Why: Correct posterior X -bites.
When: Early and / or late in treatment.
Time: 24 hours/day.
MID LINE ELASTICS
Attachment.
Upper lateral diagonally to opposite lower lateral
Force
1/4 inch 6 oz. (Ram).
4 3 2 1 1 2 3 4
4 3 2 1 1 2 3 4
Why: Correct midline discrepancy
When: finishing archwire.
Time: 24 hours/day , except when eating.
ANTERIOR BOX ELASTICS
Class II case.
4 3 2 1 1 2 3 4
________
4 3 2 1 1 2 3 4
Class lll case.
4 3 2 1 1 2 3 4
_____
4 3 2 1 1 2 3 4
LATERAL BOX ELASTICS.
Where: Upper lateral and cuspid to lower cuspid and bicuspid.
Force: 3/16 inch 6 oz (impala).
Why: Increase overbite, improve cuspid position.
When: Finishing archwire, class II malocclusion.
Time: 24 hours/ day.
Lateral box elastics: Class III.
Where: Upper lateral and cuspid to lower lateral and cuspid.
Force: 3/16 inch 6 oz (impala).
Why: Increase overbite, improve cuspid position.
When: Finishing archwire, class III malocclusion.
Time: 24 hours/ day.
BUCCAL BOX ELASTICS.
Where: Upper cuspid and bicuspid to lower bicuspids.Force: 3/16 inch 6 oz (impala)
Cephalomatric analysis:
Sagittal values -ANB more than 3 degrees.
Vertical values - will determine the type of pull for the headgear.
Dental : protrusion of anterior dentition.
Arch length discrepancy : moderate to severe crowding
( unable to treat non-extraction).
Age : Growing patient.
TREATMENT PLAN
Skeletal problems:
· objective- to correct from skeletal class ll to class l
· treatment plan : the use of headgears as an orthopedic appliance. Allow the mandible to grow into class l position.
Dental problems
· objective : to retract the anteriors into the facial bones
Treatment plan:
Extract all four first bicuspids retract anteriors into facial bones.
MAXILLARY ARCH.
· Band upper right and left first molars.
· Band upper right and left second bicuspids.
· Attach brackets to all anterior teeth.
(Observe bracket heights).
INITIAL ARCHWIRE.
The initial maxillary archwire is a flexible wire. Use either .0175 or .016 NITI. This helps to unravel the crowding in the anterior region. There is usually more initial crowding in the maxillary arch than in non-extraction cases hence these flexible wires are used for one to three months. The wire is tied down the first month with O rings, subsequent months they are tied with ligature wires. This allows faster leveling and aligning.
The bracket on the upper 1st molar has a 15 degrees rotation. When the NITI wire is placed into the bracket it is will to derotate the molars from a class ll to a class l position.
SECOND APPOINTMENT.
(One month later).
HEAD GEAR ISSUE.
(Read on head gear issue).
Guideline for applied force:
Initially 8 oz / 224 grams.
Subsequently 16 oz /448 grams.
First the head gear is activated to 8 oz by stretching the elastic module to the first dimple.
The force of application at the first dimple is about 8 oz or 224 grams. At the next visit usually about four to five weeks later the force is increased to 16 oz or 448 grams this is done by stretching the elastic to the second dimple. The force is now maintained at this level throughout the treatment. At every visit the force applied is checked and accordingly adjusted.
FACEBOW ADJUSTMENT
Use special headgear adjusting pliers.
VERTICAL - to center of lips.
TRANSVERSE - Keep inner bow expanded.
SAGITALLY - Enlarge or constrict adjustment loop.
MOLAR ROTATION - maintain molar rotation by adjusting the distal end of the inner bow.
Outer bow is kept parallel to inner bow and parallel to occlusal plane.
Orthopedic correction:
key to success-
· Growth.
· Cooperation.
· Directional pull.
· Force.
Advantage of orthopedic correction with facebow:
Affects growth in all direction.
Sagittal - cervical pull.
Vertical - high pull.
Transverse - expansion of inner bow.
Guidelines for direction of pull.
If SN - MP is :
1. Below 35 degrees.
The directional pull is cervical.
2. Between 35 and 42 degrees.
The directional pull is combination.
3. Above 42 degrees.
The directional pull is High.
GUIDELINES FOR HOURS WORN PER DAY.
If ANB is:
1. Less than 3 degrees.
Wear 8 hours (nights only).
2. Between 3 to 5 degrees.
Wear 10 hours per day.
3. More than 5 degrees.
Wear 12 hours per day.
Facebow adjustment
· Outer bow around cheeks.
· Molar intrusion
bend outer bow 20 degrees at first molar.
· Unilateral - molar class II.
Bend outer bow on class ll side outward and lengthen stop on inner bow class ll side.
SECONDWIRE CHANGE.
The second wire is .016 SS wire. It is used to continue leveling and eliminating rotation. It is also an excellent wire for retracting the canines.
Check list:
Adapt wire to template.
Bend omega loops.
Wipe in accentuated curve of spee.
Toe in .
Heat treatment.
Tie back.
Adjust headgears
Fabrication of omega loops. ( check previous Blog posting.)
The fabricated .016 round wire is now place into the arch.
Take three unit chain elastic.
Place the first ring around the head gear tube. Do not place it on the hook. Use a hemostat and stretch the third ring of the chain elastic all the way to the cuspid and attach it to the cuspid bracket. Do not engage the middle ring to the bicuspid bracket. You only attach it to the head gear tube and the cuspid. Take regular power O and put it on the biscuspid bracket. This engages the power chain to the bracket. This is a very simple procedure but it is very important to do it the right way. This simple technique will retract the canines very effectively compared to other techniques.
Reasons for cuspid retraction prior to the anterior retraction.
· There is more control over molar anchorage. As only the cuspids are retracted against the bicuspids and molars as opposed to all six anteriors. In retracting all six anterior teeth against four posterior teeth there is a tendency to burn anchorage.
· To get the cuspids into class l position quickly and build the final occlusion around this newly established cuspid position.
There are two important rules to follow.
· Do not change the power chain too often. Change it once every 4 to 5 weeks. If it is changed too often it will move the cuspids too fast and it will get completely of control. Initial tipping will occur and the tooth will not have time to upright and rotate itself back into its normal position after the force of the power chain dissipates.
· Always make sure the .016 round wire remains in the slot as the cuspid is being retracted. If it rotates out which sometimes it does. Take a ligature wire and wrap it around the bracket and re engage the wire into the slot. Place the power chain over the ligature wire. If the wire disengages from the slot of the bracket the cuspid will be totally out of control. It is very important to ensure that the wire is in the slot all the time. When the patient comes in for the appointment and when you remove the old power chain off check and confirm that the wire is in the slot. If it has disengaged and slipped out of the slot, take a ligature wire and tie it back. The wire must not be tied too tight because if it is tied it too tight then the canine will not slide back.
Question: Why do you attach the power chain to the buccal tube and not to the hook?
Answer:
· If attached to the hook it lies to close to the gingival and becomes a food trap causing irritation and gingival tissue swellings.
· The force to the power chain is less if attached to the hook, it is greater if attached to the buccal tubes.
· When warped around the headgear tube the power chain lies on the arch wire all the way to the canine.
It takes about six months to retract the cuspids changing power chain every 4 to 5 weeks.
THIRD WIRE CHANGE. (The closing loop wire).
Take a flexible millimeter ruler and measure from the distal of the lateral incisor to the distal end of the opposite lateral incisor . The obtained measurement gives the size of the closing loop wire to be selected. The loops are place about a millimeter distal to the lateral bracket. The wire size between the loops is 18x25 and the wire size distal to the loop is a reduced wire size 16x22. This unique wire has two different sizes combined in one wire. A full size wire in the anterior region and a reduced size in the posterior section. This wire is taken to the template and adapted to the arch form.
This wire does not have omega loop and it is not toed in. A slight curve of spee is place distal to the loop. The amount of curve of spee wiped into the wire always depends upon the bite. In deep bite case a large curve is placed and in not so deep bite cases a moderate curve is placed into the wire. This curve of spee is place between the loop and the first molar. The wire is cut at an angle from the outside inwards and the end is sharpened with the help of a bur. This helps to thread the rectangular wire into the slot of the molar bracket. After the wire has been place into the slot it is then activated by cinching back with a cinch back pliers. The distal portion of the wire is grasped with the cinch back pliers it is the pulled back to open the loop. In doing so the loop is activated by about a millimeter. While gasping the distal end the wire is twisted to give a 45 degree bend and this prevents the wire from slipping back into the slot. The activation in now repeated on the opposite side. It is advisable to have the patient bite on a cotton roll while this process is being carried out. It is less traumatic and give more control. The anterior teeth are now consolidated with a continuous ligature tie and the posterior teeth are ligated with individual ligature wires.
Removing the wire:
The wire is cut mesial to the molar bracket on both sides. The anterior portion is removed first then the posterior portion that has been cinched back is removed.
QUESTION: When the anterior teeth are retracted with the rectangular wire will the posterior teeth move forward? That is, will you lose anchorage?
Answer: The 15 degree rotation in the molar tube and the use of the headgear will help to reinforce anchorage. This will help to hold the posterior segment while the anterior segment is being retracted.
QUESTION: Do you use head gear every time you retract the anteriors.
ANSWER: No. You only use headgears when you want to ensure anchorage.
QUESTION : Do you have to ligate the posterior segments together?
ANSWER: No, they will not slide forward.
FINISHING WIRE.
Since there is no difference in the arch form between non-extraction and extraction arch forms, the difference being only in the arch length. The finishing arch wire is common for both type of cases. That is the .017 x .025 stainless steel. Omega loops are usually bent into this wire and place just in front of the molar tubes. The omega loop must have an acute angle so that the ligature wire will not slide off when place and tied back to the molar tube.. A slight curve of spee between the omega loop and the cuspid could be wiped in depending upon the amount of deep bite present. Since this wire is a strong wire too much of curve wiped into the wire will open up the bite and get completely out of control Slightly toe in distal to the omega loop. Care is also given not to curve the distal end too much because by this time the molars have quite well rotated so we do not have to toe in the wire a lot. The wire is tied in with ligature wires and tied back at the omega loops. The entire maxillary arch has been consolidated as one unit and the spaces will not open up. This wire is left in position till the end of the treatment. This wire also forms the base for the application of elastics and class ll or class lll mechanics.
MANDIBULAR ARCH.
The mandibular arch is banded and bonded only when a Class l cuspid relationship has been achieved. This is to avoid the impingement of the maxillary cuspid tip upon the mandibular cuspid bracket. It is always advisable to wait for the cuspids to attain class l relationship prior to the commencement of banding and bonding the mandibular arch. Hence maxillary cuspid retraction is carried out completely before mandibular cuspid bracket placement.
The first wire for the mandibular arch is the multi-stranded .0175 or .016 Ni-Ti. Turbo .017 x .025 or D- Rect .017 x .025 which is usually implemented after four to six months of‘ driftodontics’. This very flexible wire needs no adjustment. As torque control to keep the mandibular incisors upright over basal bone is not a major concern you could use the .0175 Respond or .016 Ni-Ti wire. When these wire are used a second initial wire such as .016 stainless steel round wire or an .017 x .025 D-Rect should be used for about 1 to 3 months before utilizing the closing loop wire.
Mandibular Closing loop Wire.
The closing loop wire is the .016 x .22 stainless steel wire designed to the vari-simplex archform.. The purpose of this wire is to close the extraction site. Unlike in the maxillary arch where only the four incisors are retracted, .in the mandibular arch all six anterior teeth are retracted concurrently. The mandibular closing loop like the maxillary closing loop is tear drop in shape. These teardrops are placed distal to the canine brackets.
If the most posterior tooth banded is the first molar the arch wire is place and activated exactly as in the upper arch. The opening loop is activated about 1 mm by pulling the distal end of the wire as it protrudes through the convertible tube and the distal end is now cinched down at about 45 degrees angle to the horizontal. If the second molar is banded and there is sufficient space distal to the second molar then cinching back is done in a similar way as it is done with the first molar. But most of the time there is insufficient space available distal to the second molar for cinching back the wire. In such situation an omega loop is placed in the archwire just distal to the first molar tube. The slot in the convertible tube on the first molar is removed and the tube is now converted into a bracket. This enables us to place the arch wire with the omega loops. The omega loop is now actively tied back to the second molar hook. It is tied in such a way that it opens up a space about 1 mm in the tear drop section of the wire. The closing loop is activated about 1 mm per appointment. If a severe curve of spee is present for the first time when the wire is placed. The archwire is then not activated but it is activated during the subsequent visits. Due to driftodontics in the lower arch the closing loop is used for a shorter period than in the maxillary arch. In very severe crowding case and due to driftodontics the extraction space is virtually self eliminated and a very small space about 1 mm remains. In such situation a .016 stainless steel round wire is placed and a power chain is applied from the first molar to the first molar on the opposite side. This will help to eliminate all spaces and the mandibular arch could then be consolidated.
FINISHING ARCHWIRE.
Once all the space has been closed , the .017 x .025 stainless steel wire is now utilized which is similar to the one used in the upper arch. At this stage in an extraction case when the wire is placed for the first time there is usually a large curve of spee present. It is not advisable to place any reverse curve of spee at this stage. The wire is just left flat for the first time and a couple of visits later the wire is removed and a slight reverse curve of spee is place in the wire. Omega loops are place in the wire and tied back with the help of ligature wires. It is essential to level the mandibular arch completely. When second molars are banded the omega loop are place about I mm mesial to the second molar tubes for tying back. By tipping the omega loop buccaly torque is built into the wire to compensate for the lack of torque in the second molar tubes..
ELASTIC FORCES:
Application of intra oral forces:
1. To align the maxillary dentition to the mandibular dentition to achieve proper occlusion.
2. To correct cross bite and mid line discrepancies.
3. To aid in the settling of the occlusion at the end of treatment.
Elastic forces are only applied when both the arches are in the finishing .017 x.22 stainless steel wires. Exception being only in class III cases where class III elastic are used early in treatment. And in bimaxillary protrusion cases where we need to upright the lower anteriors and retract them early in treatment.
CLASS II ELASTIC.
Attachment. Upper laterals to lower 1st or 2nd molars
force. 1/4 inch 6 oz. (Ram).
1 2 3 4 5 6 7
1 2 3 4 5 6 7
Purpose # 1
CLASS II MALOCCLUSION
When
FINISHING ARCHWIRE.
Time
24 HOURS/DAY.
Purpose #2
SLIP LOWER ANCHORAGE
( Caution do not tip lower anteriors forward).
CLASS III ELASTICS
Attachment
Lower laterals to upper 1st molars.
Force
1/4 inch. 3.5oz. (Fox).
1 2 3 4 5 6 7
1 2 3 4 5 6 7
Purpose # 1
CLASS III MALOCCLUSION.
When:
Throughout treatment.
Time: Dependent upon severity.
Purpose # 2
BIMAXILLARY PROTRUSION
(MAXIMUM ANCHORAGE).
When
WEARING COMBINATION FACEBOW
LOWER CLOSING LOOP ACTIVATED
Time.
72 HOURS, THEN NIGHT ONLY WITH FACEBOW.
Purpose # 3.
PREVENT ADVANCING THE LOWER ANTERIORS IN CROWDED NON EXTRACTION ARCH.
When
Initial archwire in lower arch.
Time
36 HOURS, THEN NIGHT ONLY WITH FACEBOW.
CROSS - BITE ELASTIC.
Where: Buccal of one arch to lingual of another arch.
Force: 3/16 inch. 6 oz (impala)
Why: Correct posterior X -bites.
When: Early and / or late in treatment.
Time: 24 hours/day.
MID LINE ELASTICS
Attachment.
Upper lateral diagonally to opposite lower lateral
Force
1/4 inch 6 oz. (Ram).
4 3 2 1 1 2 3 4
4 3 2 1 1 2 3 4
Why: Correct midline discrepancy
When: finishing archwire.
Time: 24 hours/day , except when eating.
ANTERIOR BOX ELASTICS
Class II case.
4 3 2 1 1 2 3 4
________
4 3 2 1 1 2 3 4
Class lll case.
4 3 2 1 1 2 3 4
_____
4 3 2 1 1 2 3 4
LATERAL BOX ELASTICS.
Where: Upper lateral and cuspid to lower cuspid and bicuspid.
Force: 3/16 inch 6 oz (impala).
Why: Increase overbite, improve cuspid position.
When: Finishing archwire, class II malocclusion.
Time: 24 hours/ day.
Lateral box elastics: Class III.
Where: Upper lateral and cuspid to lower lateral and cuspid.
Force: 3/16 inch 6 oz (impala).
Why: Increase overbite, improve cuspid position.
When: Finishing archwire, class III malocclusion.
Time: 24 hours/ day.
BUCCAL BOX ELASTICS.
Where: Upper cuspid and bicuspid to lower bicuspids.Force: 3/16 inch 6 oz (impala)
posted by Dr.Das | 2:25 PM
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