Here is the last installment on the MARA appliance. Included are instructions for insertion, cementation, and patient instruction. This is followed by a discussion of the Expander MARA, treatment sequence and activation, removal and continuation of treatment.

Clinical Management of The MARA by Paula Allen-Noble Part III: Insertion and Cementation of the MARA . The Expansion MARA. Treatment Sequence and Activation. Removal and Continuation of Treatment

Clinical Insertion:

Step 1. Many clinicians will take corrected tomograms or transcranial x-rays prior to seating the MARA. This is done to evaluate the initial position of the condyle and give the orthodontist a beginning baseline of joint morphology.

Step 2. Remove all separators.

Step 3. Fit crown MARA components on teeth (one at a time and then removing them to prevent aspiration) checking size and length of crown.

Note: At this time document on the patient's chart large restorations to any of the teeth receiving crowns. Crown removal on such teeth could result in a fracture if using crown removing pliers that apply pressure to the occlusal surface of the tooth. In this situation the cutting technique would be indicated at the end of MARA treatment when the appliance is to be removed.

During the initial fitting procedure, should the crown have a tight snap fit, and you cannot remove it with your fingers, use an explorer or scaler to help pry the crown loose. Avoid using band and crown remover pliers since they apply pressure to the top of the crown and can cause distortions. You may however, use these pliers if a removal hole has been pre-cut into the crown allowing the tip of the pliers to rest on the tooth enamel. Care should be taken not to distort the gingival edge of the crown.

The crown should slide on easily, with some resistance, and slide fully down on to the occlusal surface without pinching the soft gingival tissues.

Once the crown has reached about three-quarters of its seating position with thumb pressure, it is beneficial to use a bite stick to complete seating. Place handle portion of the bite stick in the central groove of the crown at an angle matching the cuspal incline and have the patient bite it down from there.

Crown Adjustments:

Crown is too loose: crimp the mesial and distal edges of the stainless steel crowns, using bird beak, Ormco crown contouring pliers, How pliers or Tweed arch bending pliers. Adjusting a crown in this manner can tighten it up to one-half size.

Tweed arch type contouring pliers.

Pearl: If the crown seems a little too large after crimping, and you still want to go ahead with cementation, recrimp the crown very sharply close to the margin or edges all around the crown including the interproximal area. Do not try the crown on the tooth again. Fill the crown completely full with glass ionomer to compensate for the extra crown space.

Note: If your MARA design does not have occlusal removal holes and you usually use a barrier on the occlusal surface of the molars, you may consider not using vaseline or Chap Stick on the tooth with the loose fitting crown. This will enhance bond strength by allowing the adhesive to flow into the occlusal grooves. You may want to make a notation on the patient's chart that extra cleanup will be required at the removal appointment.

Crown is too tight: it may have been over crimped and you will need to straighten or flatten out the edges of the crown with How pliers. You can also trim the crown gingivally. Care must be taken whenever trimming crowns because certain types of contoured crowns get considerably larger when trimmed.

Crown is too long: if the patient complains that it is uncomfortable on the gingival tissue. Using a heatless stone or scissors you can slightly trim the edges to relieve impingement. It is important to remember that the higher up you trim a crown, the looser it gets on the tooth.

Note: Crown or crowns do not fit. Upper and lower impressions for a new set of working models should be taken. The original work models may have been distorted. When possible, direct fit a new crown on the tooth. If this is not possible then give the laboratory a detailed explanation of the problem with the crown. When returning a MARA to the laboratory it is very useful for them to have the original models because examination of the original and new models may help to identify the fabrication problem.

Step 4: Evaluate the placement of the Mandibular Arms, and if present the Lingual Arch.

Adjustment to the Lingual Arch:
If a lingual arch is present, check that the lingual arch rests on the cingulums of the lower incisors. The lower crowns may be rotated a little if necessary to make the unit fit better. Make sure that the lingual arch is the correct width and is not expansive, nor narrowing to the lower molars. If adjustments required see: Delivery of MARA, Pre-Insertion Check List 3.E

Pearl: Incorporating a small omega or adjustment loop into the lingual wire during construction can make the adjustment of this component simpler.

Adjustments to the Mandibular Arms:
Adjustments are usually made with three prong pliers. Any up-down, in-out, or mesial-distal corrections must be made at this time. It is rather painful to the patient to try to make these adjustments after the appliance has been cemented.

If adjustments required see: Delivery of MARA, Pre-Insertion Check List 3.B.

Check that the mandibular arms are aligned properly. If they are out too far they will cause cheek irritation. To evaluate this effectively the upper elbows need to be in place, since the elbows will partially shield the lower arms. If the lower arms are too far inward they will not engage the upper elbows, especially in Class II.

Step 5. Evaluate the Upper Elbows. Check the elbows in the mouth to make sure the elbows and arms fit correctly both in Class II and Class I.
See: Clinical Delivery of MARA, Pre-Insertion Check List section 5.

A. Once all four of the MARA crowns have been fitted, seat them all and have the patient bite end-to-end on the incisors with the midlines on. Look to see that the space for the upper elbows is similar on both the right and left sides. There should be 4-8mm between the upper large square tubes and the lower arms. Any less will not allow the elbows to fit: any more may cantilever the elbows unnecessarily far. This distance can be adjusted by rotating the crowns on the teeth and by bending the lower arms mesially or distally.
	Too much space between lower arm and upper elbow.

B. Try in both upper elbows.

1.Torque them to fit barely outside the lower crowns.

2.Place shims on the upper horizontal legs of the elbows in order to achieve the advancement wanted and correct any midline discrepancies.

3.Both elbows should touch the arms when the midlines are on. To help this, you can vary the rotational position of the lower crown, and you can bend the lower arm backward or forward.

(If elbow adjustments are required see directions in Delivery of Mara, Pre-Insertion Check List section 3.A.)

Vary the position of the lower arm by how you seat the lower crown on the teeth.	Lower arm rotated mesially on molar.	Lower arm rotated distally on molar.

C. Check of MARA Fit and Function in the Mouth Before Cementing Crowns.

1) Test the appliance with the mandible forward in Class I position.

a. The lower arms should stick out wider than the elbows but not so excessively that they will irritate the cheek. The prominence of the lower arm is adjustable using a small beak 3-prong plier and bird beak.
b. The elbow horizontal leg should extend around 4mm distal to the large square tube, to allow tiebacks and the addition of shims later, but not longer or it may poke the cheek.
c. The elbow vertical leg should be long enough to engage the lower arm even if the patient opens a few millimeters. It should be torqued lingually enough to touch the buccal of `the lower crown.
d. The sweepback leg of the elbow should not impinge on the lower gum tissue, nor should it flare out into the cheek. It needs to extend distally enough to prevent the patient from biting behind it, yet not so far distally that it pokes the cheek.

Incorrect. Sweepback leg on elbow flares too far buccally.
	Correct. Frontal and rear buccal views of sweepback leg on elbow parallel to lower crown.

 

2) Test the appliance with the mandible retruded in the Class II position.

The lower arms should stay engaged on the sweepback arms of the elbows, and should not drop behind them or bite inside them. For this to be true, the lower arms must be long enough and the elbows must be torqued in tight enough to the buccal surface of the lower crowns, and the sweepback arms must be long enough.

Incorrect. Sweepback leg is too short, allowing the patient to bite in front of the lower arm.

Correct. Sweepback leg of elbow is long enough to prevent the patient from biting in front of the lower arm.

 

Step 6: If Applicable, Evaluate Occlusal Rests. Occlusal Rests need to be checked for their approximation to the teeth. If adjustments required refer to Delivery of MARA, Pre-Insertion Check List section 3.E.

	Adjustments to Occlusal Rests Occlusal Rest adjustments are easily made with How or bird beak pliers. However, caution should be taken when adjusting rests as they can break if annealed too much.
Occlusal rests to second molars.
	Pre-molar rests are usually bonded to the tooth and should be micro etched. (AOA Laboratory will micro-etch these rests during fabrication). Second molar rests as a rule are not bonded.
Occlusal rests to pre-molars.	Pearl: If you have made considerable adjustments to occlusal rests, crowns or bands you may want to re-micro etch before cementing the MARA.

Alternative to occlusal rests when super eruption is of concern: An alternative to metal occlusal rests is an occlusal buildup with composite/acrylic, fixed with the acid etch technique. This is usually placed on the lower second molars. Also, if intrusion of the first molars is not desired, as in deep bite cases, then lingual plateaus, or (bite turbos) can be fixed on the upper anterior teeth. Buildups are placed after the MARA has been cemented.

Prepare MARA for Cementation:

Step 1. Remove the elbows from the upper crowns. Note: Most practices find it easier to cement the MARA without the elbows attached to the upper crowns. However, if you choose to cement the upper elbows ligated to the upper crown make sure the appliance fits as described in the Clinical Insertion section C,and Cementation of MARA Step 6.
Step 2. Dry the MARA and all its components thoroughly, especially the inside of the crowns.
Step 3. Place toothpaste, lotion, or wax in any and all open areas of the MARA components. This includes upper tubes, upper and lower archwire slots, and also in the expander screw if one has been incorporated into the MARA design. Avoid getting toothpaste, lotion or wax inside the crowns as they may contaminate the cement and weaken the bond.

Cementation of the MARA

Step 1. Mix cement and place in the crowns. Crowns should be 1/2 to 2/3 full. Use a glass Ionomer cement such as, Fuji I, Ormco ProTech, or Ormco ProTech Gold. Pearl: Because of salivation, it is recommended to start cementing the mandibular arch first, then the maxillary arch.

Pearl #1: Make sure the doctor is at the chair and ready to proceed as you are filling crowns with cement. If the cement hardens, you will lose about forty-five minutes cleaning out the crowns and re-micro etching.

Pearl #2: Using "Allwrap" or a similar material over the mixing slab will cut cleanup. This material is found through dental supply houses and is the same material general dentists use to cover their equipment for sterilization considerations.

Pearl #3: Ormco's ProTech (Gold) glass ionomer is very good to use because its gold color is easily seen when cutting through the crown during the removal procedure, and during cleanup makes it easy to see that all of the cement has been removed.

Step 2. Isolate and dry tooth.

A. Cementing crowns without holes on the occlusal surface:

1. With a cotton applicator place a thin film of Vaseline or a little Chap Stick on the occlusal surface of the tooth just before placing the crown. This will keep the glass ionomer out of the grooves simplifying removal of the crown and keeping cleanup time at removal to a minimum.

2. Clean excess cement from crowns and surrounding teeth immediately using the air water syringe and suction. When using a glass ionomer there is no reason to wait for it to set up before rinsing.

3. Have the patient bite on cotton rolls to hold the crowns still while the cement sets.

B. Cementing crowns with removal or vent holes on the occlusal surface:

1. Do not use Vaseline or Chapstick on the teeth if a crown removal hole or vent has been pre-cut in the occlusal surface of the crown

2. If there is a removal hole or vent the cement should set or cure before cleaning.

3. Do not wipe the extruded cement away from the hole until it sets, and then leave a bit of excess, to retard wash out. Check for voids around the margins of the holes to avoid decalcification.

4. Because the cement escapes out of the holes, do not blow air around the removal or vent holes before the cement completely sets up.

5. Have the patient bite on cotton rolls to hold the crowns still while the cement sets.

6. Clean off any excess cement after it sets.

 

Step 3. If Applicable: Bond occlusal rests:

Prepare the teeth for light cure composite material, bonding one arch at a time. Place enough adhesive to fill in the occlusal grooves of the tooth and cover the metal rests. Cure adhesive with light.

Note: Second molar rests are not normally bonded.

Pearl #1: An adhesive booster is suggested to increase bond strength.

Second molar rest.	Occlusal rest bonded to pre-molar.

Inserting MARA Elbows:

Insert MARA Elbows: Slip the upper elbows into the upper square tubes, guiding the patient's lower jaw into the advanced forward position. At first, patients have a tendency to resist closing in this position. Telling the patient to bite their front teeth in an edge-to-edge position seems to help them learn the new bite pattern.

Patient biting edge-to-edge. Elbow engages lower arm correctly.

Bite Functioning Check List and Adjustments:

Step 1. The patient should be able to open and close in front of the upper elbows without interference from the appliance. Note: If the mandibular arms extend more than 2mm buccal to the upper elbow, cheek sores are likely.

Upper elbow torqued correctly. Lower arm does not extend 2mm beyond elbow.

If the patient is unable to close completely because the expansion of the maxillary arch is not sufficient, and consequently the inner surfaces of the upper elbows are touching the buccal surface of the mandibular molars, then the elbow should be torqued more buccally See Delivery of the MARA, Pre-Insertion Check List section 3.A.

Elbows torqued incorrectly interfering with closure.	Elbow torqued correctly.

Step 2. Check that the patient's midlines are lined up and that the occlusion has been advanced correctly.

Midline and advancement correct. Elbows torqued correctly.

If midlines are off, correct by placing a shim /bushing on the upper elbow as described in Delivery of the MARA, Pre-Insertion Check List section 3.C.

Midline off. MARA requires shim added to elbow to correct.	Midline corrected with shim added to elbow.

Step 3. Have the patient close completely in Class I and check that the upper elbow distal extensions do not protrude too far out. If they do they will cause irritation and sores.

Distal extension should not exceed 3mm.	Elbow extensions correct in all dimensions.

Step 4. If the patient has been advanced properly, but is able to bite behind the elbows, you will need to replace the elbows with elbows that have longer sweepback legs.

If the upper elbows are too long or too short in any dimension, correct at this time as described in the MARA Delivery, Pre-Insertion Check List section 3.A.

Elbow sweepback leg too short. Patient biting behind the elbow.	Elbow sweepback leg longer. Patient can't bite behind the elbow.

Step 5: Check the position of the mandibular arm. If the arm is too (wide) it will impinge on the soft tissue of the cheek, causing sores. The lower arm when articulated against the upper elbow should not extend any further than 2mm wider than the upper elbow. If the lower arms need adjustments, correct at this time as described in MARA Delivery, Pre-Insertion Check List section 3.B. Note: Only minor intraoral adjustments are possible at this point.

Incorrect. Small space between lower arm and elbow.	Correcting lower arm distally to close space.	Correct. No more space between lower arm and elbow.

Step 6: Securing upper elbows to upper crown: (Ligation Technique) If there are no problems with the MARA's lower mandibular arms, or the upper elbows, and the appliance fits properly, tie in the elbows with a double braided ligature wire. .014 single braided ligature wire has been found not to break.

Step 1. Twirl an .014 ligature wire, or use a double braided ligature of smaller size.	Step 2. Run ligature through tieback eyelet and hold the ligature and elbow together in a Mathieu plier.
Step 3. Insert the elbow and wrap the ligature around the elbow's distal extension.	Step 4. Pull the ligature forward.
Step 5. Twirl the two ends of the ligature together.	Step 6. Cut excess ligature and tuck the tail into interior of elbow.

Properly Fitted MARA

Post Insertion Information and Instructions:

It is important to inform patients and parents that there will be an adjustment period and that problems associated with the appliance can arise. Discuss these issues in detail at the exit interview. A "Care Kit" and a written "Instruction Sheet" should be sent home with the patient. Educating and communicating with patients and parents empower them to take a pro-active role in the management and care of their appliance during therapy, minimizing frustrations and resulting in fewer emergency appointments.

If the patient is a minor the parent should always be present at the exit interview:

1. Explain that the patient will have to make a conscious effort to bite forward with the lower jaw until their muscles become accustomed to the new position, and it will take a good week before they feel completely comfortable. (Illustrate this for the parent and patient by physically guiding the patient's lower jaw forward as they bite down, allowing the parent to see how the appliance functions properly.)

This is a perfect opportunity to point out to the parent and patient how good the chin and profile looks when biting correctly in the appliance.

2. The patient may bite their cheeks until they learn to avoid it.
3. Explain that there will be difficulty in eating for four to ten days, and they will be biting on their incisors. Suggest that they cut most of their food into small pieces, keeping frustration with chewing to a minimum. They will be able to eat just about anything on their normal diet in a few days.
4. If it is not noted on the chart that the patient is a bruxer or mouth breather, ask the parent if the child sleeps with their mouth open at night. If they do, you may want to give the patient vertical elastics to keep the mouth closed while sleeping.
5. Explain the possibility of the lower arm getting locked into the upper elbow. Assure them this doesn't happen often, but if it does and they cannot disengage it with gentle movement, they are to call your office and your office will provide immediate care. Explain that unlocking the appliance can be done easily in the orthodontic office by simply cutting the ligature wire and sliding the elbow forward. Once either elbow is removed, they unlock easily from the other side.

Note: If it is a concern that a patient is a bruxer or sleeps with their mouth open and retruded as a mouth breather may, elastics can be used to help keep the patient's mouth closed and in the Class I position while sleeping.

 

6. There is not a hamster look with the MARA, but sometimes a patient may have a puffy look of the cheeks. Explain that the puffiness will disappear over the next several weeks.

7. The patient may experience soreness in the cheek area. Inform them that the soreness will go away as the tissue toughens and that a callus forms.

Provide the patient with Orabase with Benzocaine, wax or cotton rolls to help alleviate any uncomfortable symptoms.

Should the patient experience an unusual degree of irritation or discomfort, below are listed few options that may be of help.

a. A button the size of a silver dollar can be made with lab silicone to cover the offending attachments, usually the lower arm. (Fibers from a cotton roll can be incorporated into the silicone for strength.)

b. A light cured material such as Barricade (a periodontal product) can be temporarily attached to offending MARA attachments.

c. A thick elastic can be stretched over the upper elbow, incorporating the circumference of the elbow during the day and including the lower arm at night. Or place elastics vertically, distal and mesial on the elbow, slipping them over the horizontal leg to the lower sweepback leg.

8. Explain that due to the exceptional forces on the appliance during chewing a crown may come loose.

9. An upper elbow can be lost in spite of their being tied in with ligature wire. If the elbow comes loose, request the patient save it and bring it back when they come in to have the elbow re-tied.

10. Patients and parents should always be given written information flyers that describe the appliance, its function, possible problems with solutions. Each office should create their own unique information sheet.

 

Expander MARA: Clinical Considerations

Clinical Delivery of the Expander MARA: Delivery of the of the Expander MARA is basically the same as described in the section on Clinical Delivery of the MARA with the following exceptions:

1. The upper elbows and the lower crowns will not be attached until expansion is complete.
2. Before cementing make sure that all the orifices in the expander, large square tubes and archwire tubes are filled with toothpaste or wax to keep out glass ionomer. (If using wax, be careful not to get the wax on the inside of a crown.)

Expander MARA ready for cementation.

 

Pearl: Pre-cutting elbows that will be placed after expansion can sometimes be inaccurate due to the changes in the arch width. When pre-cutting the assembly a technician can only approximate the length that will be required by taking into consideration the amount of expansion allowed by the expander itself and how far the clinician wants to advance the patient after expansion. It may be advisable to request that the laboratory send the elbows uncut, and make the adjustments in the clinic after the expansion is complete.

Post Insertion Instructions:

Expanders are usually turned several times before the patient leaves the office. The assistant makes the first turn of the expander with the parent watching. Then the parent should turn it. This ensures that the parent is turning it correctly. If upper and lower expanders are present, review the procedure for both. The amount of turns and the amount of time required for maximum expansion depends on:

1.The maximum expansion allowed by the screw.
2.The number of turns required to fully open the screw. (Because of the variations in design follow the manufacturers guidelines, or ask the laboratory to provide information pertaining to the expander.)
3.The expansion desired for the patient.

The patient is scheduled to be seen in four weeks to check if expansion is complete.

Completion of Expansion and Continuation with MARA Therapy:

Maxillary Arch:

Once the maxilla is expanded to the width desired:

1. Cut the expander off the appliance. Due to hygiene considerations it is prudent to remove the expander as soon as possible. A palatal arch is not needed to hold the expansion, because once the elbows are engaged they will hold the arch and keep the expansion from relapsing.
2. Cement the mandibular crowns.
3. Attach the upper elbows and advance as prescribed.
4. Schedule bracket placement if applicable.

Mandibular Arch:

Completion of mandibular expansion usually occurs before placement of the lower MARA. Once lower expansion is completed it should be retained with a lingual arch or lower braces. (When the lower arch has been expanded, it is recommended that the MARA be fabricated with a lower lingual arch.)

Treatment Sequence and MARA Activation

Treatment protocols are different depending on the treatment philosophy and mechanics being used by the clinician. Some clinicians prefer to expand the arches first (many skeletal Class II malocclusions require maxillary and/or in some cases mandibular expansion,) correct the AP with the MARA and then place brackets on Class I cases. Others like to incorporate the expanders into the MARA, expand their patients and then continue their treatment plan; correcting rotations, aligning and leveling the arches. When brackets are used in conjunction with the MARA they are usually placed sometime during the first ten weeks after insertion of the MARA to begin combined treatment mechanics and/or to:

1. Prevent the upper molars from distalizing by placing an upper 2X4 appliance to tie the upper arch together. This will encourage more of an orthopedic effect on the maxilla.

2. Prevent distal tipping of the upper molars by placing a heavy rectangular archwire.

Note: Occlusal rests are also incorporated into the MARA design if this a concern. However, because there is no vertical force as with the Herbst, tipping is usually minimal except in adults.

3. Counter the possible protruding effect of the MARA on the lower incisors, which has been reported on the average to be less than 1mm. The lower molars must be stabilized with either a lingual arch and/or lower braces. If only a lingual arch is used some minor incisor proclination will occur, which can be corrected after MARA therapy or by placing (negative 5-10 degree torque) brackets on the incisors in conjunction with the MARA.

Pearl: If orthodontic appliances are going to be used with the MARA, it is important not to place brackets on the upper second bicuspids, as they may interfere with insertion and removal of the elbows.

MARA with lingual arch and no orthodontic appliances.	MARA without lingual arch and with orthodontic appliances.

MARA therapy usually takes 12-15 months, but can be shorter or longer depending on the severity of the Class II being corrected and the age of the patient. The appliance is activated two to four times during treatment. Clinicians will activate the MARA approximately every 10-14 weeks and in increments of 2-3mm achieving and maintaining an edge-to-edge relationship. Recent research has shown that smaller incremental advancements of 1-2mm elicits a dental change while larger advancements of 3-4mm promote more of an orthopedic change.

Patient ready for first activation of MARA. Bite has deepened, needs advancement shims/bushings.	First activation of MARA completed.

Note:

The goal is to advance the incisors to end-to-end incisal relationship. As with the Herbst overcorrection with the MARA is necessary due to an anticipated relapse of 10%-20% caused by muscle pull and remodeling in the posterior glenoid fossa.

1.A medium 4-5mm Class II can be advanced the entire 4-5mm initially. This advanced position will be maintained by adding the appropriate shims/bushings to the upper elbows keeping the patient in the end-to-end incisal relatiionship throughout MARA therapy.

2.A severe 8-9mm Class II should be advanced only half way (4-5mm) when the appliance is fabricated and held there for six months. Because relapse may occur shims/bushings may have to be added to the upper elbows to maintain the initial 4-5mm advancement during the first six month period of MARA therapy. Then advance the remaining distance to end-to-end incisal relationship and hold there for the next six months or until the end of MARA therapy. Onec again, shims/bushings may need to be added during this time to maintain the advancement.

Activating or Advancing the MARA:

Step 1. Cut out the upper elbow ligatures and remove the elbows.

A. If the distal extension of the upper elbow is long enough simply add the advancement shims/bushings to the anterior part of the horizontal leg of the upper elbow, re-check the advancement as well as the midlines. If the midline is off correct by replacing a shim/bushing of the appropriate length to re-align as described in the Delivery of MARA, Pre-Insertion Check List section 3.C.

Elbow distal extension of horizontal leg long enough to support advancement.	MARA advanced using existing upper elbow.

 

B. Check the vertical leg of the upper elbow. If it is too short, place new longer elbows and place the appropriate size shims/bushings over the anterior portion of the horizontal leg to achieve the desired advancement. The elbows must be tall enough in their vertical leg that the patient can open a few millimeters before escaping the mandibular lower arm. This holds the mandible forward even when relaxing.

Note: When replacing upper elbows follow the instructions as described in the Delivery of MARA, Clinical Insertion Step 5.C.

Upper elbow vertical leg too short. Engagement easily lost.	Upper elbow vertical leg corrected. Engagement maintained.

 

Step 2. If the appliance has been adjusted and the patient is functioning correctly, tie the upper elbows in with the ligature wire,(preferably an .014 ligature wire.) For ligation instructions, see Delivery of MARA, Bite Functioning Check List and Adjustments Step 6.

Determining When to Remove the MARA:

Treatment time with the MARA typically takes about a year but the determining factor for many clinicians is when the tomogram or transcranial x-ray shows that the Temporal Mandibular Joint has remodeled and the condyle is reasonably centered in the fossa. Getting to this point may take up to 24 months depending on the severity of the Class II correction and age of the patient.

Review of Changes Produced by the MARA Over the Course of Treatment:

NOTE:

If tomograms or transcranials are not available, a guide clinicians use for determining the end of MARA therapy is that the patient have the ability to protrude the mandible 8-13mm beyond end-to-end incisors.

Pearl: When it is determined that the patient is ready to be rescheduled for MARA removal and will be continuing with edgewise finishing treatment, it is advantageous from a production/scheduling stand point to place separators (5's and 7's) at this time. At the next visit, remove the appliance, fit and cement posterior bands and bond the teeth as indicated. This sequence will save several appointments.

Removal of the MARA

Before discussing the current removal techniques let's reflect back on where the removal procedure actually begins. Crown removal actually starts prior to cementation of the MARA.

1. If occlusal removal holes are not present in the crowns, using Vaseline or Chap Stick on the dried occlusal surface of the molars will prevent the glass ionomer cement from forming a bond down in the occlusal grooves, which makes removal difficult.
2. Utilizing a tinted glass ionomer such as ProTech Gold (Ormco) helps to distinguish the cement from the tooth enamel when cutting into the crowns, and when cleaning off cement.
	Horizontal slit.
3. Placement of a horizontal slit, to be used in conjunction with an occlusal removal hole later, affords a purchase point necessary to accommodate certain styles of crown removal pliers.	Vertical notch.
4. Placing a vertical notch in the crown before delivery of the appliance simplifies the removal procedure by eliminating the need to use a bur subgingivally if the crowns are to be sectioned, and if a crown slitter plier is to be used.

Crown Removal Cutting Technique:

Step 1. Place a topical anesthetic on the gingival tissue in the areas where the crowns are to be cut.

Step 2. If applicable: remove the composite material from occlusal rests freeing them from the teeth.

Step 3. Using a bur cut the crowns occlusally and down to the mesial gingival margin. On the upper crowns, make the cut occlusally and down the mesiopalatal cusp gingival margin. On the lower crowns, make the cut occlusally and down the mesiobuccal cusp.

Maxillary crown cut.	Mandibular crown cut.

Step 4. The crowns are then removed using crown or band removing pliers along with a rocking and peeling motion utilizing the attached upper elbows and lower arm for leverage. A band seating plier can also be used to grab the lower arm to assist in removal of the crown.

Cut maxillary crown removed with a band plier.	Cut mandibular crown removed with a band removing plier.	Cut mandibular crown removed with band seating plier.

Crown Removal Pliers Technique:

Step 1. Place a topical anesthetic on the gingival tissue in the areas where the crowns are to be removed.

Step 2. If applicable: remove the composite material from occlusal rests freeing them from the teeth.

Step 3. Find or place a crown removal hole 2-4mm in diameter in the occlusal surface of the crowns. Place the post of the plier into the occlusal hole and slide the lower beak of the plier into the horizontal slit of the crown for the upper and under the buccal arm on the lower. Apply pressure and the crown will snap off. (It is not necessary to remove the upper elbows prior to crown removal.)

Maxillary crown removed with crown removing plier.		Mandibular crown removed with crown removing plier.
	Chastant (AEZ) crown removing plier.

Pearl: On the upper crown a horizontal slit may be placed on the mesial lingual corner to act as a purchase point for the pliers. (Many crowns are slightly sub-gingival and accessing the edge of it could be uncomfortable for the patient.) The purchase point should be half way from the gumline to the occlusal.

Crown Slitting Pliers Technique:

Step 1. Place a topical anesthetic on the gingival tissue in the areas where the crowns are to be removed.

Step 2. If applicable: remove the composite material from occlusal rests freeing them from the teeth.

Step 3. Find the vertical removal notch previously created at the mesial gingival corner and engage the blade of the crown slitting plier into the removal notch and the pad of the plier on the occlusal surface of the crown. The plier should be held at a slight angle to the occlusal plane.

Maxillary crown: hold the slitter slightly below the occlusal plane.
Mandibular crown: hold the slitter slightly above the occlusal plane. This slight angling enhances attack of the point and blade of the slitter keeping the point riding underneath the crown in an occlusal direction. As slitting occurs, the width of the blade forces the crown apart and the crown is easily removed. The crown usually comes off in the jaws of the slitter, or is aided by peeling the crown from the tooth. (Leave elbows attached to crowns for leverage.)

Maxillary crown removed with crown slitting plier.	Mandibular crown being removed with crown slitting plier.

 

Cement Removal:
As discussed earlier, simplifying the removal of the cement started with cementation. If vaseline or chapstick was used on the occlusal surface of the tooth prior to cementation most of the cement will have remained in the crown when removed. This occurs for two reasons: First, the crown was micro etched enhancing adhesion inside the crown and secondly, Vaseline/Chapstick forms a barrier or shield between the tooth surface and cement in the occlusal grooves. If these shields were not applied, or a removal/vent hole was incorporated during fabrication, which preclude the use of a shield, the cement will remain adhered to the occlusal grooves, making cleanup slightly more time consuming.

Step 1. Place lip retractors for a clear working field.

Step 2. Dry the cement with a tooth dryer. This will help to break the cement away from the tooth.

Step 3. Use an ETM #800-3490 (Ormco) bond removal pliers to break away as much of the cement as possible.

Step 4. Use a bur similar to the type used to remove bonding material in a slow speed or a high speed polishing handpiece to finish the cleanup.

Pearl: There is plenty of space between the molars and pre-molars when the crowns are removed. This is a good time to place posterior bands and bond the teeth as indicated. This sequence will save several appointments.

Note: Depending on the mechanics used during MARA therapy, you may notice that the first molars are intruded from having the crowns between the occlusion, but they will be elevated when brackets and archwires are placed. This problem usually disappears during full treatment. However, if not, the patient can wear light vertical elastics.

Posterior open bite after removing MARA crowns.

Continuation of Orthodontic Treatment
Finalization of the occlusion is determined by a number of factors, such as whether or not orthodontic mechanics were utilized by the clinician during MARA therapy. Some clinicians like to use brackets to control the torque of the teeth, and to level and align the teeth during MARA treatment. When the MARA is removed, the rest of the teeth are then banded or bracketed to finish detailing the occlusion.

MARA with brackets.

Another philosophy is to simplify the correction of Class II cases by completing the patient's treatment in phases:

1. Expand the upper and/or lower arches.

2. Correct the AP with MARA therapy.

 

3. Remove the MARA appliance

4. Place brackets on uncrowded Class I cases.

 

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About the Author:

Paula is the clincal liason for Allesee Orthodontic Appliances (AOA). Many of you know Paula from her 30 years in the industry. She worked in an orthodontic practice for fourteen years and has attended and lectured at continuing education seminars, presented staff and doctor's clinics at the Great Lakes, Midwest, Southern, and Mid-Atlantic constituent meetings, as well as, for the American Association of Orthodontists. Paula has visited and interacted with hundreds of orthodontic offices. Her experience in orthodontics covers a wide range of areas.

 

She can be reached at: p-allen-noble@mindspring.com or 1-800-990-3485

Paula S. Allen-Noble
Clincal Liason Allesee Orthodontic Appliances (AOA)
13931 Spring Street Sturtevant
WI 53177 USA

or more directly:

Paula S. Allen
Clincal Liason (AOA)
463 Club View Drive
Lawrenceville, GA 30043 USA