growth modification of different types of malocclusion

Growth modification of different types of

malocclusion

Prof. Maher A. Fouda

Prepared by:- Bilal A.M.Faculty of dentistry-

Mansoura university - Egypt

GROWTH MODIFICATION

Growth modification attempt to change skeletal relationships by using the patient’s remaining growth to alter the size or position of the jaws.

PATIENTS EXAMINATION

Patient’s examination. 1- personal details. 2- complaints and motivation. 3- dental history . 4- medical history . 5- extraoral examination. 6- intra oral examination.

ORTHODONTIC RECORDS

1- study models2- x- ray:- A- cephalometricB- panoramicC- prei apical if neededD- bite wings if neededE- occlusal if neededF- hand wrist (imperative).

Hand wrist x-ray

Growth modificationThree assumptions are made when growth modification is undertaken:-

1- first and most obvious, the patient must be growing.- Females are best treated between the ages of 9 and

11 years.- males are best treated between the ages of 11 and

13years.

Growth modification-2 The second assumption is that the orthodontist can diagnose the skeletal discrepancy and design treatment that will apply the appropriate amount and direction of force to correct the discrepancy.

Growth modification-3 The third assumption is that the growth modification is only the first phase of a two-phase treatment plan.

How does Growth modification work??

Three theories are offered:-1- the first theory suggest that growth modification appliance change the absolute size of one or both jaws.2- the second theory is that growth modification may work by accelerating the desired growth but not changing the ultimate size or shape of the jaw.

2- the second theory is that growth modification may work by accelerating the desired growth but not changing the ultimate size or shape of the jaw.

3- the third possibility is that growth modification may work by changing the spatial relationship of the two jaws. The ultimate size of the jaw and its rate of growth are not changed, but by modifying the orientation of the jaws to each other, a more balanced profile may result.

Biological age and hand radiograph:

HAND AND WRISTX-RAY:

■ In evaluating any group of normal children of the same

chronolgic age, it is clear that each has his own characteristic

growth time clock, i.e. there is early, middle and late maturars,

so chronolgic age is not an accurate indicator of the stage of

development. In an effort to determine a child's develompental

age, methods of assessment using skeletal maturation (hone

age) have been devised.

Hand wrist x-ray

The hand and wrist have been used most commonly for assessment of pubertal maturation. The hand and wrist may be easily radiographed, with minimal radiation exposure to the rest of the body. The union of the epihyses with their diaphyses occurs in specific order, which in females is advanced 3-4 years compared to that in males. (Diaphysis is the shaft of long bone.

Epiphysis: Portion of a bone which in early life is distinct from the shaft). Between the ages of 12.5 and 14 years the most active transformation of the epiphyseal cartilages occurs concurrently with peak height velocity and after completion of the permanent dentition through the second molars. Skeletal age was found to be more highly correlated with menarcheal age, and menarche usually occured soon after the fusion of the epiphyses of the distal phalanges with their shafts.

1 -Chapman has proposed a radiographic method using a standardsized dental film to assess the development the first metacarpophalangeal joint. The development of the adductor sesamoid is staged according to ossification. The onset of ossification of the sesamoid occurs at the beginning of the adolescent spurt in height and maximum velocity usually occurs at the "seed” stage.

It gradually increases in circumference over a period of 2 - 3 years. Immediately after the inital verification that the adductor sesamoid has started its calcification statural height and facial components begin a rapid, and definite spurt in their developmental growth velocity. A limiting factor in using this clinical signal is that without serial records the clinicians may have difficulty in determining with accuracy when the sesamoid started its mineralization if it is present at the time of the first recording.

It a significant percentage of calcification of the sesamoid has taken place the individual is beyond the pubertal phase of accelerated growth. The converse is also true without any initial signs of calcification that is the circum-pubertal growth spurt may be reliably assumed to have not yet begun.

Sagittal discrepancy

Characteristic features of Skeletal class II patients.

Skeletal Class II malecc^sien may be characterized by both sagittal and

vertical discrepancies:

Sagittal discrepancies:

a. Prognathic maxilla and erthcgnathic mandible.

( maxillary protrusion).b. Retrognathic mandible and crthcgnathic maxilla, (mandibular

retrusion.) or

c. a combination of both.

FUNCTIONAL APPLIANCES TO TREAT CLASS II DIV I

Definition

Removable or fixed orthodontic appliances which use forces

§enerated by the stretching of muscles, fascia and /or

Peridontium to alter skeletal and dental relationships.

Average angle casesWhen ????- Functional appliance treatment should be started beforethe pubertal growth spurt- This is the time when the mandible may exhibitincreased growth which may be influenced- Duration—10-12 hours a day.- These appliances should be worn at night-time as this iswhen growth takes place

Activator

Activator

Class II div I due to maxillary protrusion I- Extra oral

examination- Retrognathic profile - Patient is asked to protrude the mandible, to give a

simulation of how the facial appearance would be if mandibular growth occurred.

Case Report

11 year old male

Uncrowded Class II division 1 malocclusion with an overjet of 11.5 mm, and an upper midline diastema of 1.5 mm, with a minor left-side crossbite.

2- Impressions It’s important to ensure a good

impression in the lower lingual sulcus area.

3- Study casts

3- Study casts

4- Intraoral Examination

5- Radiographs

CEPHALOMETRIC X-RAY AND ANALYSIS

Assessment of overjet

Assessment of ANB angle ANB +2 - +6

Assessment using Wits appraisal

Wits appraisal -1mm to + 4.5 mm

Activator

The andreson activator Monoblock design Comprises upper and lower

acrylic fused together and has a solid palate. The labial bow lies against the upper incisors palatal wire to minimize palatal tilting of upper incisors and has no clasps.

The Andresen type activator is a tooth-borne passive appliance that opens the bite and the mandible is advanced for Class II correction

The activator consists of a single block of plastic constructed so that lingual flanges on lower cause the mandible to be positioned forward

Mandibular incisors are capped so that forward movement is resisted while the mandibular posterior teeth are free to erupt.

Steps of construction

A piece of wax of approximate 6 x 8 cm dimensions is warmed in hot water and folded over to make a soft roll

Register the bite with the mandible in a protruded position

Alternatively, bite may be registered by means of exacto bite.

The indentations in the wax form the lower teeth should be 2 or 3 mm deep.

Construction bite registration for TB appliance taken in edge to edge position with Exactobite stick.

Patient bites with incisors edge to edge similarily 6mm separation of molars

Fold wax lengthwise twice to 1/3 size .Do not

flatten

Turn folded wax lengthwise and fold once with spatula in between

Crimp lower edge against spatula. Do not flatten

Patient bites with incisors edge to edge

Final wax bite

The impressions are poured in stone and carefully mounted on a plane line articulator, ensuring that the bite is correct.

The labial bow of 0.8 mm wire is reinforced with stainless steel tubing where it will enter the baseplate

The tags of the labial bow are turned down at right angles to the palate.

The softened roll of wax is placed just below the occlusal surfaces of the teeth and pressed firmly into the embrassures between the teeth and spread onto the palate

The upper and lower baseplates are waxed

Incisal edges of mandibular anteriors are capped with a thin layer of wax

The completed waxed up activator

The appliance embedded in the deep half of the flask

The finished appliance

Activator■ Stimulation of myotactic reflex activity, causing isometric muscle

contractions.

■ Lose fit of appliance with low vertical dimension

■ Muscle force transmitted onto teeth: uses kinetic energy

■ Increased activity of elevator and protractor muscles with relaxing and

stretching of retractors.

Activatorother views:

■ Muscle contraction: superior head ٥ ۴ lateral pterygoid muscle

-Petrovic (rat studies), McNamara (primate studies)

-variations in the mode and direction of dislocation of mandible.

■ Condylar unloading: Lysle Johnston

For the average angle cases, the acrylic can be left untrimmed to restrict eruption of the lower molars.

In low angle cases, acrylic trimming is done to allow eruption of posterior teeth.

It is possible to grind grooves into the acrylic adjacent to upper molars and premolars, so that they are guided in a distal and buccal direction during eruption, and this can help to maintain good lateral arch coordination as the overjet reduces.

Buccal movement of a molar tooth by means of a pad of rubber pulled into an undercut hole in the baseplate.

Andresen was constructed using a wax bite with the mandible protruded approximately 8 mm.

- It was worn for 10 months

- The lower molars and second premolars were free to erupt.

10 months later The overjet was reduced from 11.5 mm to 3.5 mm

using only the Andresen appliance for 10 months

The molars and premolars were in Class I relationship

Class II Treatment

9-year-old female patient with severe overbite and Class II malocclusion before treatment.

Placement of twin block appliance with bite jumping screws.

Immediate improvement in soft-tissue profile.

Class III Treatment

Bite jumping screws built into anterior acrylic plate of maxillary Class III bite blocks.

12-year-old female patient before treatment.

A. Twin block with initial bite advancement of 3mm. B. After seven months of treatment, with further bite advancements made by adding spacers of 3mm, 3mm, and 2mm bilaterally.

After seven months of twin-block therapy.

Case report : Start records

Modified twin block

Post twin block

Pre adjusted Edgewise appliances

Post treatment records

Passive functional appliances

Frankel

Active functional appliances

Removable active functional appliances Bionator

Head gear activator

Active functional appliances

Fixed active functional appliances Herbst

Duration and timing of wear Functional appliance treatment should be started

before the pubertal growth spurt This is the time when the mandible may exhibit

increased growth which may be influenced Functional appliances should be worn for at least

10-12 hours a day These appliances should be worn at nighttime as this

is when growth takes place

INDICATIONS

1- Growing ages (Mixed dentition and/or early permanent dentition)

2 – Skeletal considerations (Sagital correction ofclassll&lll)

Skeletal Class // with Short mandible.

A- Class II division I

B- Class II division 2 (Convert div 2 to div 1).

1- Vertical Considerations

Normal to low angle cases.

2- Dental Considerations

- Local irregularity and rotation of incisors especially upper incisors

- Crowding or dental compensation (Pre-functional Orthodontics

require

3- Open bite/ deep bite correction

4- Cross bite correction

5- To correct mal-forming dysfunction

CONTRAINDICATIONS

1- Children with neuromuscular disorders

a. Poliomyelitis

b. Cerebral palsy

2- Compliance

3- Hyperdivegent faces

4- unfavorable growth

5- Protruded lower incisors

6- Severe crowding

7. Age

High pull Face bow Van Beek appliance incorporates high

pull face bow and buccal capping. It also incorporates incisor cappings. It is indicated in the treatment of anterior open bite.

High pull Face bow High pull face bow can be attached to

maxillary intrusion splint. The splint incorporates acrylic coverage of all the teeth in the upper arch .

Treatment of class II div I by extra oral appliance.

High pull headgear holds or intrudes posterior teeth.

Case 1 before and after treatment.

Low pull face bow Cervical pull face bow exerts

force below the level of occlusal plane will tend to extrude the upper molar teeth and thus cause an increase in the vertical dimension of the lower face. While this may be an advantage in a patient with a deep overbite and reduced lower facial height, it is contraindicated in a patient with open bite and increased lower face height .

Low pull face bow

Cervical headgear

Cervical pull headgear

•Point of attachment lies below the occlusal plane ,the external force is

directed inferiorly as well as posteriorly.

•With the face bow the cervical attachment permits the creation of force

vector that permits the extrusive and distal movement of molars.

• Force vector is altered when the angle of the face-bow in relation to the

dental bow and the length of the face-bow are changed.

Spring – Gear with adjustable levels of force

Cervical fashion releasable headgear

Cervical fashion releasable headgear

Cervical fashion releasable headgear

Vertical discrepancy

High pull headgear

- Point of attachment is above the occlusal plane

- The extra oral force is directed superiorly and posteriorly.

- High attachment permits the force vector to correct

anteroposterior maxillary excess and vertical maxillary excess.

- Force vector is altered when vertical position of the outer

bow is changed.

High pull headgear

High pull headgear

High pull headgear

Present day

straight pull headgear- External force is directed to more surface area - more comfort.

- direction of the force vector can be modified.

- If the forces are equal for each attachment the resulting force

vector is usually above the occlusal plane but inferior to the vector

created with the occipital attachment alone.

- Requires more patient CO operation

Duration of the force- At least 12 to 14 hrs per day (Klein 1957, Rickets 1960).

- Recommended in the evenings- growth hormone release is

higher. Growth hormone enhances the new bone formation at

the epiphyseal plates of the long bones in growing children.

Magnitude of the force.

- For dental movements -15 to 400gms per side depending on

the size and tooth movement,

- A minimum force of 250 gm per side (total 500gm) is enough

for to modify skeletal change.

- To maximize the potential for skeletal change, orthopedic

force - 400 to 900 gm per side [ 1 to 2 pounds ] (Graber 1965).

Timing of force application

- Orthopedic effect in growing children

- Most active period of growth.

1- Just before the eruption of permanent teeth or in mixed dentition

2 - during the pubertal growth spurt.

Cervical pull headgear

٠ Point of attachment lies below the occlusal plane ,the external force

is directed inferiorly as well as posteriorly.

٠ With the face bow the cervical attachment permits the creation of

force vector that permits the extrusive and distal movement of molars

٠ Force vector is altered when the angle of the face-bow in relation

to the dental bow and the length of the face-bow are changed.

The sagittal correction of Class II cases may be brought

in several ways:

- Relocating the maxilla backward or inhibiting its growth,

- Moving the upper teeth distally.

- Releasing forward growth of the mandible,

- Moving the lower teeth mesially.

- Inhibiting the vertical growth of the maxilla.

- Inhibiting eruption of upper posterior teeth while permitting

eruption of lower posterior teeth.

Low angle cases.

The treatment objectives in cases of this nature are to:

- reposition the maxilla posteriorly.

- permit forward growth of the mandible.

- promote eruption of lower posterior teeth.

- promote extrusion of the upper molars and distal eruption of the

remaining upper posterior teeth.

- restrain the anterior vertical growth and eruption of teeth, and

- prevent mesial drift of lower posterior teeth and buccal tipping of lower

incisors.

Extra oral force is mandatory for 2 reasons:

- There is an extensive skeletal discrepancy due essentially to a protracted maxilla and,

- The lower incisors would not be tipped further labially, which happens often when activator are used alone.- Extraoral appliance of choice Cervical headgear, since it has both a distal and an inferior force component.

Straight pull headgear

Average angle cases

٠ Class II children with ncrmal face height (many of whom have anterior deep bite because of excessive eruption of lower incisors) can be treated with either headgear or a functional appliance.

٠ If molars are moved distally and extruded, the mandibular plane angle tends to increase.

٠ straight-pull or interlandi headgear is preferred over cervical headgear, to reduce elongation of maxillary molars and better control

Average angle cases

- It is a combination of the high-pull and cervical headgear.

- Main advantage is pure posterior translatory force as required in Class II

malocclusion with no vertical problems.

- This is accomplished by placing the force vector through the center of

resistance, parallel to the occlusal plane.

-This means bending the outer bow to the same level as CR, and hooking

the elastic to a notch at the same vertical level. This prevents anterior

migration of maxillary teeth, or possibily even translate them posteriorly.

(A), Normal occlusion; (B), Class I malocclusion;(C), Class II malocclusion; (D), Class III malocclusion. Note the position of the mesial cusp of the maxillary molar relative to the mandibular molar in each type of occlusion.

Orthopedic TreatmentThe goal of orthopedic treatment is to maximize the skeletal changes and minimize the dental changes produced by the orthopedic force. The method and effect of growth modification by the orthopedic appliances depend on the initial age of the patient and their skeletal pattern. Orthopedic treatment should be limited to children with active growth remaining. Since more skeletal change is obtained when orthopedic treatment is started early, it is recommended to start treatment in the early mixed dentition stage (eruption stage of the permanent incisors and first molars).

For treatment with a chin cap ,orthopedic treatment should be continued until growth is complete or when the growth rate is decreased. Remaining growth should be evaluated not by chronological age but skeletal age. Skeletal age may be assessed by either hand-wrist radiographs, change in height or secondary sexual characteristics, or using the vertebral maturation method. Annual cephalometric radiographs are considered most accurate in evaluating completion of skeletal growth. Cephalometric analyses can also help in determining whether the skeletal Class III problem is due to an underdeveloped maxilla, overdeveloped mandible, or a combination of both.

The choice of orthopedic appliances for growth modification is usually determined according to the patient’s skeletal pattern. In general, chin caps are used in children who have an overdeveloped mandible while rapid palatal expansion (RPE) and/or maxillary protraction is used in patients who have a maxillary deficiency.

In addition, to obtain optimal treatment results, it is important for the patient to wear the orthopedic appliance for more than 12 hours a day. Therefore patient cooperation is paramount in orthopedic treatment of Class III malocclusion patients.

Chin CapIn patients with an overdeveloped mandible, chin caps have been used in an effort to inhibit mandibular growth. However, there are limitations in its use since the mandibular condyle is a growth site rather than a growth center. According to reports by Mitani and Sugawara,6 chin cap therapy on children with overdeveloped mandibles was effective during the period of treatment but lacked long-term stability due to relapse from catch-up growth of the mandible.

Dermaut and Aelbers also stated that chin cap therapy is best used on mild skeletal Class III patients or asauxiliary measures in patients wearing functional appliances.

Since the main effect of chin cap therapy is backward and downward displacement of the mandible with linguoversion of the lower incisors, its use should be limited to children with a pseudo (functional) Class III or a mild Class III malocclusion. For patients who have an overdeveloped mandible, it is prudent to plan for orthognathic surgery after growth is complete.

Class III malocclusion with mandibular excess

There is some evidence that a chin cup is more effective in young children under age 7 than the same treatment used later.

Unfortunately despite efforts to modify excessive mandibular growth, many of these children ultimately need surgery, and the chin cup treatment is essentially

camouflage.

High pull Chin cup Chin cup is used to inhibit or control forward

growth of the mandible in skeletal Class III patients. Patients with mandibular excess can usually be recognized in the primary dentition despite the fact that the mandible appears retrognathic in the early years of most children .

Maxillary retrusion

Simultaneous use of Monoblock and elastics

Developing class III treated by Balters Bionator

Reverse twin block

In mixed dentition stage , the face mask is attached to hooks opposite the laterals . The hooks are soldered to labial arch which is soldered to first molar bands . The labial arch is at the level of the gingival third . A palatal arch is also adapted to the teeth and is soldered to the molar bands from the palatal aspects of the teeth .

DIAGNOSIS AND ETIOLOGYThe patient, an 8-year-old girl, came to the

Kangnung National University Orthodontic Clinic in Gangneung, South Korea, with a chief concern of “my bite is not right.” Clinically, she had a concave facial profile, and acute nasolabial angle, and a protrusive mandible.

TREATMENT PROGRESSPhase 1 treatment was started at age 8 years 4 months with

a maxillary removable appliance to regain space lost from the early loss of the deciduous molars (Fig 4). After 6 months of observation, a surgical miniplate was placed. Local infiltration anesthesia was administered to the maxillary left and right buccalvestibular areas after surgical disinfection. A vestibular incision around the canine area was performed. After an atraumatic subperiosteal dissection to the infrazygomatic crest, a curvilinear miniplate was adapted, bent to the zygomatic buttress’s bony surface, and fixated with 3 self-tapping miniscrews per side.

Phase 1 treatment included a maxillary removable appliance to regain space lost by early loss of the deciduous molars.

Location of the miniplate relative to the zygomaticomaxillary suture. Note that this figure is only for visualization purposes as this is a skull of an adult, and the anatomic contour of the zygomatic process of the maxilla changes with age

After atraumatic subperiosteal dissection to the infrazygomatic crest, a curvilinear miniplate was adapted, bent to the zygomatic buttress bony surface, and fixated with 3 self-tapping miniscrews; B, screws should be placed in a posterior-superior direction to prevent damage to the premolar tooth follicles. Cha et al 103 American

Maxillary protraction was started 2 weeks after placement of the miniplates, with a force of 300cN per side applied 12 to 14 hours per day (Fig 6). Within 10 months of treatment, a three quarters premolar width Class II molar relationship was established. Thereafter, the patient’s wearing of protraction headgear was limited to nighttime only as a retainer for 10 months. The plates were removed after the facemask treatment. A mucoperiosteal incision and a subperiosteal dissection were performed to expose the miniplate. The monocortical screws were removed first, and the miniplate was then detached because often new bone is deposited next to the plate. The surgical site was then closed and sutured.

Maxillary protraction was started 2 weeks after placement of the miniplates.

Progress records taken at age 10 years 7 months showed favorable growth between the maxilla and the mandible, and the malocclusion could be camouflaged by orthodontic treatment. The patient was treated with fixed appliances for 18 months to establish a good molar relationship and correct the midline discrepancy. A maxillary circumferential retainer and a mandibular lingual fixed retainer were placed after appliance removal. The patient was instructed to wear the retainer at night for 10 to 12 hours.

TREATMENT RESULTS After 14 months of protraction headgear treatment the

malocclusion was overcorrected to a Class II molar relationship to compensate for future excessive mandibular growth. Superimposition of pretreatment and posttreatment cephalometric tracings showed 8.1 mm of forward movement of A-point and 3.3 of counterclockwise tipping of the palatal plane . The ANB angle changed from –2.2 to 1 6.7. The SNO, or angle between the anterior cranial base and orbitale, changed from 63 to 70. Labial tipping of the maxillary incisors and lingual tipping of the mandibular incisors, which are typically observed after tooth-borne protraction, were not seen with the miniplates.

Progress photographs after 14 months of protraction headgear treatment.

Intraoral photographs near the end of phase 2 fixed appliance treatment.

Postretention photographs 27 months after appliance removal.

Maxillary ProtractionIn children with an underdeveloped maxilla, maxillary growth can be facilitated by means of an orthopedic force with a protraction device.To encourage forward and downward growth of the maxilla, it is most effectively performed when the maxilla is protracted as one rigid unit. For this reason, labiolingual appliances, removable appliances, or fixed appliances with strong heavy wires can be used. However, RPE is considered one of the most popular and effective appliances.

Figure 5. Miniscrews inserted on the palatal or labial side of the alveolar bone and connected to the RPE by wires and direct resin for maxillary protraction. (A) Occlusal view; (B) anterior view.

Previous studies have shown that patients protracted after opening the midpalatal suture with RPE showed greater forward displacement of A point than patients protracted with a labiolingual appliance and no midpalatal suture opening.

Recently, miniscrews have been inserted on the palatal or labial side of the alveolar bone and connected to the RPE to reinforce the maxilla. For patients with increased lower face height, a posterior bite blocks on the lower dentition or bonded RPE appliances can be used to avoid an increase in the vertical dimension.

Figure . (A) Anterior open bite was created after maxillary protraction by backward and downward rotation of the mandible. (B) Miniscrews were implanted on the palatal slope for intrusion of maxillary molars for bite closure. (C) Anterior openbite was closed after the second phase of treatment.

There have been numerous reports regarding maxillary protraction with orthopedic force.However, relapse following treatment has been seen in certain patients after growth has been completed. According to Sung and Baik, the direction of the forward and downward displacement resulting from the maxillary protraction was similar to that of a Class I control group while the amount of forward and downward maxillary displacement measured at A point was significantly greater than that in the Class I control group.

However, during the observation period of 1 year following protraction, the amount of maxillary growth in the protraction group was found to be less than the control group, indicating the possibility of short-term relapse. Figure below shows a 14-year 6-month-old Class III patient with an underdeveloped maxilla and a fairly long mandibular body length.

The patient was treated with an RPE and facemask for 1 year and6 months and treatment was completed withfixed appliances. Due to the maxillary protraction, the mandible rotated backward and downward resulting in an increase in mandibular plane angle from 42.1° to 43.9° and a 2-mmanterior open bite.

Figure 9. A 14-year 6-month-old male with a Class III openbite malocclusion treated with an RPE and facemask (A-F) and fixed appliance with molar intrusion using miniscrews in the second phase (G-L).

Because of these changes, miniscrews were implanted between the upper first and second molars for intrusion in the second phase of treatment. Following treatment,the openbite was closed and the mandibularplane angle returned to 42.8°.

Figure 9. A 14-year 6-month-old male with a Class III openbite malocclusion treated with an RPE and facemask (A-F) and fixed appliance with molar intrusion using miniscrews in the second phase (G-L).

Arch expansion

It`s one of means of creating space in dental arches

Expansion can be classified into:

- rapid maxillary expansion devices - slow expansion devices

Rapid maxillary expansion (RME)

can be used to correct unilateral or

bilateral posterior cross-bites and it occurs

when the forces applied to the teeth and

the maxillary alveolar process exceeds the

limit needed for orthodontic tooth

movement and the applied pressure acts as

an orthopedic force that opens the

midpalatal suture.

The maxilla articulates with ten other bones of the face and the cranium.

Fig . 3D reconstruction from CT image: occlusal view showing complete parallel opening of midpalatal suture from median diastema, 2 parts of maxilla, palatal processes to posterior nasal spine.

•As sutural patency is vital to R.M.E, it is important to know

when does the suture closes by synostosis.

• On an average 5% of suture is closed by age 25 years.

Earliest closure occurs in girls aged 15 yrs. Greater degree of

obliteration occurs posteriorly than anteriorly.

•Ossification comes very late anterior to incisive foramen –

this is important when planning surgical freeing in late

instances of RME

We will use a new classification for RPE appliances as follow:

RPEFIXED

Banded

Bonded

REMOVABLE

The Hyrax appliance is essentially a non-spring loaded jackscrew with an all-frame that is soldered to the bands on the abutment teeth. This type of appliance causes the least irritation to the palatal mucosa and it is easier to maintain good oral hygiene with it.

A rapid palatal expander with a habit breaker added.

Hygienic Rapid Palatal Expander with occlusal wires

Hamula developed what the hygenic RPE

Haas introduced an appliance which is a tissue borne fixed appliance. He believed that his appliance can cause more parallel expansion forces on the two maxillary halves and that the forces are more evenly distributed on the teeth and the alveolar processes.

The appliance is attached to the teeth, with bands on the first molars and first premolars, and to the palate, by acrylic pads between the first premolar and first molar.

1. Patients who have lateral discrepancies that result in

either unilateral or bilateral posterior crossbites

involving several teeth are candidates for RME.

RPE: Hyrax DesignBands on 6's & 4's

RPE: Hyrax DesignBands on 6's

RPE: Dishinger Bonded Design embedded in

acrylic splints Bonded RPE with a wire framework that has acrylic splints

Case report 1 . This case is treated by rapid palatal expander (RPE), is generally worn for four to six months. During the first few weeks of wear it is necessaryto expand (activate) the appliance.

Hyrax Rapid Palatal Expansion (Expander) Dr. Yan Razdolsky D.D.S., L.T.D. - YouTube.flv

Rapid Palatal Expansion

Two weeks later, half of expansion is completed

Expansion is completed

ACTIVATION OF THE RME APPLIANCE

•The basic principle of the appliance involves the

generation of forces that are capable of splitting the

mid-palatine suture. Hence, the forces should be

definitely more than the usually used orthodontic forces.

•The forces generated are close to 10 to 20 pounds. An

expansion of 0.2 to 0.5-mm should be achieved per

day. The screw is activated at between 0.5 to 1mm per

day and about 1 cm of expansion can be expected in 2

to 3 weeks.

•The activation schedules tend to vary depending upon the

age of the patient and form of the appliance. Timms has

suggested an activation of 90°,morning and evening for

patients up to the age of 15 years. In Patient above this age,

he suggests an activation of 45° four tirnes aday.

schedules of activation

• Zimring and lsaacson recommended, two turns per day for

initial 4 to 5 days followed by once turn per day in growing

individuals. For adults the recommended two turns each for the

first two days followed by one turn per day for the next 5 to 7

days and then only one turn every alternate day till the desired

expansion is achieved.

HOW TO TURN THE EXPANDER

Radiograph showing the swallowed object in the

stomach.

For rapid maxillary expansion

activation keys, some steps must

be followed. The first is to use

dental floss tied around the key

and then rolled up on the finger to

allow ready recovery in case of

deglutition or aspiration.

Pre Expansion

Post Expansion

Case report 2 Constricted maxilla and posterior crossbite treated with (RPE).No spaces for the canines.

Unilateral crossbite treated with RPE Case report 3 5-year-old patient who presented with a constricted maxilla and a lateral mandibular shift on closure. A Hyrax type of rapid palatal expansion appliance was used to correct the posterior crossbite.

Pre treatment

Post treatment . Note the midline diastema formed by skeletal expansion.

MINISCREW-ASSISTED NONSURGICAL

PALATAL EXPANSION BEFORE

ORTHOGNATHIC SURGERY FOR

A PATIENT WITH SEVERE MANDIBULAR

PROGNATHISM

• A transverse maxillary deficiency in an adult is a

challenging problem, especially when it is combined

with a severe anteroposterior jaw discrepancy. The

demand for nonsurgical maxillary expansion might

increase as patients and clinicians try to avoid a 2-

stage surgical procedure—surgically assisted rapid

palatal expansion followed by orthognathic surgery—

and detrimental periodontal effects and relapse

• In this regard, a miniscrew- assisted rapid palatal

expansion was devised and used to treat a 20-year-old

patient who had severe transverse discrepancy and

mandibular prognathism.

• Sufficient maxillary orthopedic expansion with

minimal tipping of the buccal segment was achieved

preoperatively, and orthognathic surgery corrected the

anteroposterior discrepancy.

•The periodontal soundness and short-term stability of

the maxillary expansion were confirmed both

clinically and radiologically.

•Effective incorporation of orthodontic miniscrews for

transverse correction might help eliminate the need for

some surgical procedures in patients with complex

craniofacial discrepancies by securing the safety and

stability of the treatment, assuming that the suture is

still patent.

Pretreatment facial photographs

Pretreatment intraoral views showing severe transverse and anteroposterior jaw discrepancy

Pretreatment casts

Fabrication and application of the MARPE: A, fabrication on the cast; B-D, placement of the appliance and

expansion procedure for 6 weeks; E, after consolidation and arch alignment at 10 months.

Periapical views during maxillary expansion: A, before expansion; B, after 4 weeks of expansion, with the upper diastema temporarily closed by resin buildup for esthetic

reasons; C, after consolidation and arch alignment at 6 months.

Posttreatment facial photographs

Follow-up intraoral photographs18 months after debonding; F, axial computed tomogram showing the 3-

mm apical level from the cementoenamel junction 12 months after debonding

Slow Palatal Expansion The second category for maxillary expansion is the slow

maxillary expansion group. These appliances apply slow and continuous forces which do

not attempt, as a main objective, to open the midpalatal suture.

These appliances include: removable expansion plates , Porter W arch, and Quad-Helix.

Quad Helix Appliance Part 2 - YouTube.flv W arch Quad-Helix

Case report 4 a patient in the mixed dentition and has a bilateral posterior crossbite will be treated with 3D Quad helix

Pre treatment

Pre treatment occlusal view

Transverse dimension (49mm molar width) of the maxilla before treatment.

After 2 months After 4 months

Beginning of Treatment

Before and After Quad-Helix 3D expansion – 5 months total time

Transverse dimension (57mm molar width) of the maxilla after expansion (8

mm width addition by expansion)

Case report 5 bilateral posterior crossbite treated with Quad helix

During expansion

After expansion Pre expansion

After treatment is completed

Case report 6 a 5-year-old boy who presented with a unilateral posterior lingual crossbite and a lateral mandibular shift due to a width discrepancy between the maxillary and mandibular arches. The discrepancy between the width of the maxilla and that of the mandible caused the mandible to deviate to one side to occlude on the posterior teeth.

Unilateral crossbite treated with slow palatal expansion

The preferred treatment is to increase the width of the maxillary arch by the use of a fixed or removable appliance. This case is treated using a W-arch expansion appliance. The W-arch was constructed with ,036-in stainless steel wire.

Pre treatment Post treatment

Case report 7 a case had unilateral crossbite .An unequal W-arch used to correct a true unilateral maxillary constriction. The side of the arch to be expanded has fewer teeth against the lingual wire than the anchorage unit. Even with this arrangement, both sides can be expected to show some expansion movement

Removable Expanders

Transverse Expansion of the Arches

Active plate splitted in the midline will expand constricted maxillary arch almost totally by tipping the posterior teeth buccally .Not by opening mid-platal suture.

Therefore this appliance is not indicated for skeletal crossbites or dental expansion for more than 2 mm per side.