Age factor in PAOO.
Indications and contraindications .
Advantages and Disadvantages of PAOO.
Biology underlying PAOO.
Complications and side effects.
Case reports .
Wilckodontics also known as Periodontally Accelerated Osteogenic
Orthodontics (PAOO), is a clinical procedure that combines selective
alveolar corticotomy, Particulate bone grafting and the application of
orthodontic forces. This procedure is theoretically based on the bone
healing pattern known as the regional acceleratory phenomenon (RAP) .
This procedure was developed by Dr .Thomas wilcko and Dr .William
Wilcko in 1995. Thomas is a periodontist and his brother Willlam Wilcko
is a orthodontist.
William wilcko Thomas wilcko
Corticotomy : Surgical procedure whereby only the cortical bone is cut
or perforated or mechanically altered. The medullary bone is not
Osteotomy: Surgical procedure through both the cortical and medullary
Difference between Corticotomy and Osteotomy
Wilckodontics combines two major philosophies of orthodontics.
The mechanical nature referring to the brackets and wires and the
biological/augmentative nature referring to the bone and gums around
the teeth. The amalgamation of these philosophies has resulted in a
New Orthodontic treatment name the “Accelerated Osteogenic
Surgically assisted orthodontic tooth movement has been used since the
1800’s. Corticotomy - facilitated tooth movement was first described by
L.C. Bryan in 1893. However, it was first introduced in 1959 by Kole as
a mean for rapid tooth movement.
Kole’s procedure involves the reflection of Full thickness flaps to expose
buccal and lingual alveolar bone, followed by interdental cuts through
the cortical bone and barely penetrating the Medullary bone
(Corticotomy style). The Subapical horizontal cuts connecting the
interdental cuts were osteotomy style, penetrating the full thickness of the
alveolus. Because of the invasive nature of Kole’s technique, it was never
History of Wilckodontics
Then in 1991, Suya replaced supra apical horizontal osteotomy with
horizontal corticotomy subapical osteotomies were replaced by cuts
limited to the cortical portion of the alveolar bone. Hence the first
description of a surgical attempt to enhance orthodontic treatment only
corticotomies called as Selective Alveolar Decortication (SAD).
Kole and Suya attributed the accelerated tooth movement by selective
corticotomy to moving “blocks of bone”.
Both believed that teeth were embedded and moved in “blocks of bone”
connected to each other by medullary bone only, instead of today’s
understanding of how teeth move through alveolar bone. Therefore, they
postulated that with less resistance from medullary bone compared with
that from the denser cortical plate, rapid tooth movement could be
A more recent surgical orthodontic therapy was Introduced by Wilcko
which included the innovative strategy of combining corticotomy
surgery with alveolar grafting in a technique referred to as
Accelerated Osteogenic Orthodontics (AOO) (Wilcko et al., 2000) and
more recently called as Periodontally Accelerated Osteogenic
Orthodontics (PAOO) (Wilcko et al., 2008).
Unlike a usual corticotomy, PAAO does not just cut into bone, but
decorticate it – that is some of the bones external surface is
removed. The bone then goes through a phase known as osteopenia,
where its mineral content is temporarily decreased. While the
alveolar bone is in the transient state of demineralization, there is
accelerated tooth movement, because the bone offers less resistance
to the orthodontic forces.
PAOO can be done on people of any age, as long as they have a
healthy periodontal situation. According to Dr .Wilcko, this
technique has been done on children as young as age 11 years and
on senior citizens as old as 77 years (mainly as preparation for dental
implants or devices).
It is particularly useful in adult patients due to there is increasing
chance of hyalinization will occur during treatment ,Cell mobilization
and conversion of collagen fibres is much slower in adults than in
Children and more prone to periodontal complications since their
teeth are confined in non-flexible alveolar bone.
Indications and contraindications
1. Class I with moderate to severe crowding.
2. Class II with extraction (To accelerate Canine retraction after premolar
extraction or Enmass retraction of anterior teeth) or expansion.
3. Mild class III cases.
4. To facilitate eruption of Impacted teeth.
5. Molar intrusion and Openbite correction.
6. Molar Uprighting.
7. Molar Distalisation.
8. Arch expansion.
1. Severe class III cases. (Class III cases have many physical constraints
which may not lend themselves to AOO treatment)
2. Active periodontal disease or gingival recession are not good
candidates for PAOO.
3. It should not be considered as an alternative for surgically assisted
palatal expansion in the treatment of severe posterior cross-bite.
4. It should not be used in cases where Bimaxillary protrusion is
accompanied with a gummy smile, which might benefit more from
segmental osteotomy .
5. Abnormal skeletal relationship between jaws.
6. Patients with uncontrolled diabetes mellitus, compromised
immune system and patient incompliance.
7. Patients with Long term use of medication such as anti-
inflammatory, immunosuppressive or steroids .
8. Patients with inadequately treated endodontic problems.
10. Persons who are taking medications that slow down bone
metabolism, such as bisphosphonates and NSAIDs.
11. Uncontrolled Osteoporosis or other bone diseases.
ADVANTAGES AND DISADVANTAGES OF PAOO
Advantages of PAOO
1. Reduced treatment time: this technique will reduce treatment time to
1/3rd to 1/4th time of conventional orthodontics.
2. Less root resorption due to decreased resistance of cortical bone .
3. More bone support due to the addition of bone graft.
4. Improved periodontal support, both gum and bone support for the
5. History of relapse reported to be very low.
6. Less need for extra-oral appliances like headgear.
7. It can be used to expedite the rate of movement of Individual teeth or
Dental segments, i.e. canine and incisor retraction.
8. Alveolar grafting also benefits the patient by repairing bony dehiscences
8. In the ten years since PAOO was first applied, the patient’s outcomes
were good. 18
1. Extra-surgical cost.
2. Mild invasive surgical procedure like all surgeries and Post-surgical
crestal bone loss and recession may occur.
3. Some pain and swelling is expected .
4. Not applicable to all cases , Proper case selection is necessary to attain
a good result. Maxillary and mandibular arch crowding with normal
skeletal relationship and incisors retraction are the main indications .
5.Patients who take NSAIDS on regular basis or have other chronic
health problems cannot be treated with this technique. 19
In PAOO technique, cortical bone is scarred surgically on both labial
and lingual sides of the teeth to be moved followed by grafting. The
tissue of alveolar bone release rich deposits of calcium and new bone
begins to mineralise 20-55 days. While the alveolar bone in this
transient state braces can move teeth very quickly, because bone is
softer and less resistance to force of braces.
The patient is seen every 2 weeks and the rapid tooth movement
produced after PAOO is substantially different than periodontal
ligament cell-mediated tooth movement. Recent evidence suggests a
localized osteoporosis state, as a part of a healing event called regional
acceleratory phenomenon (RAP), may be responsible for the rapid
tooth movement after PAOO.
RAP was first described by Frost in 1983, he noted that the original
injury somehow accelerated the normal regional healing processes. This
acceleration is the regional acceleratory phenomenon.
RAP usually occurs after a fracture, arthrodesis, osteotomy or bone-
grafting procedure and may involve recruitment and activation of
Precursor cells necessary for wound healing concentrated at the site of
RAP is a normal physiologic healing , but it can enhance the hard and
Soft tissue healing stages 2-10 times .
Shih and Norrdin demonstrated that when intraoral cortical bone was
injured by corticotomy, RAP accelerated the normal regional healing
processes by transient bursts of hard and soft tissue remodelling.
The two main features of RAP in bone healing include
1) Decreased regional bone density , but not its volume
2) Accelerated bone turnover
which are believed to facilitate orthodontic tooth movement .
The RAP begins within a few days of injury, typically peaks at 1–2
months, usually lasts 4-6 months in bone and may take 6 to more than
24 months to subside .
As long as tooth movement continues, the RAP is prolonged. When RAP
dissipates, the Osteopenia disappears . When orthodontic tooth
movement is completed, an environment is created that favours alveolar
Before opting for the periodontal surgical technique and beginning with
the procedure , a Complete medical review of the patient is done to
rule out any systemic and local factors that may interfere with the
A meticulous phase 1 therapy involving scaling and root planning
and oral hygiene instructions to the patient given. Once the local
factors have been controlled patient is recalled for the periodontal
A thorough Clinical and Radiographic Evaluation for the patient is
done to evaluate the periodontal status of the patient. It can be
evaluated by use of
1. Full mouth IOPA x - rays.
3. 3D Imaging
PAOO can be used in both Maxillary and Mandibular arches. However,
the decision regarding the site of PAOO can be made based on clinical
For example, maxillary expansion generally requires more time than
correction of mild mandibular anterior crowding. So a case with a
narrow maxilla and mild anterior crowding in mandible may benefit
with PAOO in the maxilla and traditional orthodontic therapy in the
On the other hand, a case of Bimaxillary Dentoalveolar Protrusion
requiring extractions in both the arches can be treated with PAOO to
hasten the result in both the arches. Having both arches corrected in a
similar time frame is ideal. 29
The orthodontist has a limited amount of time to accomplish accelerated
tooth movement. This period is usually 4 to 6 months, after which
finishing movements occur with a normal speed. Given this limited
“ window ” of rapid movement, the orthodontist will need to advance
arch wire sizes rapidly.
The surgical technique for PAOO consists of 5 steps viz.
1.Raising of flap.
4.Closure of flap.
5.Orthodontic Force Application.
Pre - operative patient preparation
1. On the day of surgery, orthodontic archwire was removed in maxilla,
in case of mandible there is no need for removal of arch wire due to
proper accessibility and patient was asked to perform mouth brushing .
2. 2 grams of Amoxicillin was taken by the patient orally 30 minutes
prior to the Surgery , in case of allergy to penicillin drugs advice
Clindamycin or Erythromycin 500mg orally.
3. On the dental chair Chlorhexidine mouthwash was performed by
1. Flap Design
A proper flap design is essential for the success of any surgical procedure.
In PAOO also the flap should provide proper access to the alveolar bone
wherein corticotomies are to be performed. Preservation of the gingival
form is also important for proper esthetic appearance.
After administration of local anaesthesia , Crevicular incision is made
buccally and lingually extending at least two to three teeth beyond the
area to be treated.
The flaps were reflected beyond the apices of the teeth , if possible.
Special care was taken not to perforate the flaps and any interdental
papillary tissue that remained interproximal was left in place.
Care should be taken not to damage any of the neurovascular bundles
exiting the bone and not to disturb muscle attachments.
Decortication refers to the removal of the cortical portion of the
The purpose of the decortication is to initiate the RAP response and not
to create movable bone segments.
After flap elevation, decortications of bone adjacent to the malpositioned
teeth is performed by using low-speed No.1 or No.2 round diamond
burs , in Canine region use straight diamond bur under the Copius
amount of saline irrigation.
In the PAOO procedure, decortication is performed at clinical sites
without entering the cancellous bone, avoiding risk of damage to
underlying structures, such as the maxillary sinus and the
The corticotomies are placed on both the labial and lingual (palatal)
aspects of the alveolar bone.
A typical vertical groove will be placed in the inter radicular space ,
midway between the root prominences in the alveolar bone.
This groove will be extended from a point 2 to 3 mm below the crest of
the bone to a point 2 mm beyond the apices of the roots about 1.5 -
2mm in depth.
These vertical corticotomies are then connected with a semicircular
shaped corticotomy in the apical region.
If the alveolar bone is of sufficient thickness, solitary perforations
may be placed in the alveolar bone over the radicular surface. Cortical
perforation can be made at selective areas to increase blood supply to
the graft material.
However, if cortical bone is estimated to be less than 1 to 2 mm in
thickness, these perforations are omitted to ensure no damage to the
WHAT EVER IS THE PATTERN , AIM IS TO
INJURE TO THE BONE 40
3. Particulate Grafting
The materials most commonly used for grafting after decortication are
deproteinized bovine bone, autogenous bone(Maxillary tuberosity,
Mandibular symphysis, Angle of the mandible, Ramus of
mandible and Exostosis), decalcified freeze-dried bone ,allograft
or a combination there of .
No objective data exist comparing one grafting material with another
in terms of superiority.
The decorticated bone acts to retain the graft material. The use of
Platelet rich plasma or calcium sulfate has been reported to increase the
stability of the graft material.
Resorbable grafting materials wetted with an antibiotic solution were
applied directly over the activated bone.
Frequently used augmentation grafting mixture :
2 parts demineralized freeze-dried bone (DFDBA) and 1 part bovine
bone wetted with clindamycin phosphate solution(0.5 mg/ml) applied
at a rate of 0.5 to 1 ml of grafting mixture per tooth to be moved.
Antibiotic produces soothening effect and prevent the surgical site
infection and act as a medium for placement of graft material to the
Grafting is done in most areas that have undergone corticotomies. The
volume of the graft material used is dictated by the direction and
amount of tooth movement predicted, the pre treatment thickness
of the alveolar bone and the need for labial support by the alveolar
A typical volume used is 0.25 to 0.5 ml of graft material per tooth .If
excess graft material is placed this result in difficulty in full closure of
Flap Closure Technique :
The flap should be closed using Non - resorbable interrupted 3-0
sutures without creating excessive tension. No packing is required. The
sutures are usually left in place for 1 to 2 weeks .
After closer of flap Orthodontic arch wire was secured back into
This is particularly important to the adult patient who presents with
significant gingival recession ,dehiscence and fenestration.
In these situations a sub-epithelial connective tissue graft is placed
over the denuded root surface in addition to particulate graft placement.
This connective tissue graft is harvested by removing a 1 to 2mm
thickness of gingival connective tissue from the elevated palatal flap or
Acellular dermal matrix allograft (AlloDerm).
PAOO with Gingival augmentation Technique
Vercellotti & Podesta (2007) introduced the use of Piezosurgery in
conjunction with conventional flap elevations to create an environment
conducive to rapid tooth movement.
Dibart et al(2010) introduced a procedure known as Piezocision,
minimally invasive procedure combining microincisions, minimal
piezoelectric osseous cuts to buccal cortex only and bone and soft
tissue grafting concomitant with tunnel approach.
Gingival vertical incisions are made interproximally below the interdental
papilla using a number 15 surgical blade and kept as much as possible in the
attached gingiva . All of the incisions (and the graft when required) are
made only buccally.
Then , Ultrasonic instrumentation (BS1 insert Piezotome™, Satelec
Acteon Group Merignac, France) is used to perform corticotomy cuts
through the gingival micro-incisions and to a depth of 3 mm.
At the areas requiring bone augmentation, a tunnel is performed by
means of an elevator inserted between the gingival incisions to form
sufficient space for receiving the graft.
The allograft is then placed and the incision sutured (absorbable
Advantages of piezocision
1. Shorter surgical time. (i.e., 45 min to 1 h is usually sufficient for
a complete surgery on both the maxilla and mandible with bone grafting
against 3-4 hours for traditional techniques.)
2. Minimally invasive technique.
3. No periodontal complications such as mild bone loss and partial loss of
interdental papilla which occurred in raising a flap .
4. Post-operative morbidity is less.
Disadvantages and limitations of piezocision
1. Because of the lack of muco - periosteal flap elevation, cortical
incisions may present a risk of root damage particularly in areas of
close root proximity.
2. Extra care is also required as to the location of gingival incisions. It is
very important to keep at least 2 mm from the gingival margin to avoid
the formation of gingival cleft.
3. Postoperative scar formation in case of gingival pigmentation.
Germec et al (2006) introduced “ Modified Corticotomy,” they
demonstrated a “conservative” technique to shorten the treatment
time during lower incisor retraction.
In this modified technique, corticotomy done only on the buccal side
without lingual cuts.
Modified Corticotomy Technique
It technique had logical modification because the surgically induced
transient osteopenia (RAP) described by Frost is sufficiently elicited for
most kinds of Orthodontic tooth labial movement. Germec et al’s use of
minimal intervention to achieve a specific clinical objective suggests a
knowledge of RAP and respect for a discrete surgical technique.
1. Surgical time is less compared to classical technique.
2. Technique is less sensitive.
3. Patient acceptance is more and discomfort (Morbidity) is less.
However, the potential for the non - operated lingual surface “pull”
of gingival and periodontal tissues postoperatively presents a
It is eliminated by simple circumferential Supracrestal fiberotomy or
Transmucosal Perforation with a irrigated bur may improve this
potential relapse factor, if the acceleration of the incisors retraction
begins to slow.
An alternative approach has been recently introduced by Park et al (2006),
consisting of incisions directly through the gingiva and bone using a
combination of surgical blades and a surgical mallet.
While decreasing the surgical time due to No flaps or sutures ,there
is only cortical incisions.
1.This technique did not offer the benefits of bone grafting to increase
periodontal support in the areas where expansive tooth movement was
2.The extensive hammering in office to perform the cortical incisions
appears to certain patients to be Somewhat aggressive. In addition,
highly use of the hammer and chisels in the maxilla adds dizziness and
benign paroxysmal positional vertigo .
Propel is a device uniquely designed to perform corticotomy procedure. It
is a novel technique that creates micro - osteopeforations.
Propel is an FDA-registered 510k exempt Class I device designed for
single use only.
The instrument provides a surgical stainless-steel leading edge similar
in appearance to an orthodontic mini-screw, but uniquely designed and
patented to be used to atraumatically perforate the alveolus directly
through keratinized gingiva as well as movable mucosa.
Propel alveolar micro – Osteoperforation technique
Apply topical anaesthetic or infiltrate the area(s) with a local anaesthesia .
Assess the alveolar bone for the appropriate tip-length needed to
maximize the depth of the perforation both mesial and distal to the
Then, make perforations with smooth rotations of the instrument to the
appropriate depth until the LED light goes on indicating depth has been
Control any bleeding with the application of a vasoconstrictive agent
such as Astringent or just apply minimal pressure for one minute with
The Propel device is specifically designed and patented to maximize the
remodelling process, while eliminating soft-tissue damage and enabling
orthodontist the ability to accelerate treatment.
1. Instrument is high cost ($149).
Laser is an acronym for Light Amplification by Stimulated Emission of
Lasers consist of an active medium and a pumping source enclosed in
an optical cavity. The pumping source pumps the active medium from its
ground state (inactive state) to an excited state. Very intense flashes of
lights or electrical discharges pumps the lasing medium and creates a
large collection of atoms in excited state for the laser to work efficiently.
Based on the active lasing medium, it can be a container of gas or a solid
Hibst et al (1988) were the first to report the use of the Erbium: Yttrium
Aluminium Garnet(Er: YAG) laser for ablation of dental hard tissues.
Advantage of Erbium : Yttrium Aluminium Garnet(Er: YAG) laser :
1.It had Dual ability to ablate soft and hard tissues with minimal
damage because their wavelengths(2,940 nm) lie within the absorption
spectra of water and soft tissue, causing the ablation phenomenon.
2. Irradiation effect limited to an ultra-thin layer of tissue(No damage of
surrounding tissue ).
3. Faster bone repair(healing) after irradiation than conventional bur
4. Suitable alternative for defect and root surface debridement in
conjunction with periodontal surgery.
The Er,Cr;YSG laser device (Waterlase, Biolase, USA) was used to deliver
an energy range about 300 mJ at pulse rates of 20 Hz.
The Laser ablation or bone cutting was performed under water-spray cooling
to improve the absorption of laser radiation by the bone and thus to prevent
thermal interactions like carbonization in the region adjacent to the laser-cut.
Duration of laser irradiation for each penetration was between 0.25 - 0.5
second and it was in a noncontact manner with a 2 mm distance. The
proportion of air and water was 40% and 20% respectively.
Advantages of laser corticotomy
1. It Creates a clear, dry field with no bleeding, decreasing the possibility
2. Less trauma in the surgical field.
3. Post-operative swelling , scars and pain is minimal.
4. The possibility of infection is decreased.
1.High cost compared to conventional method.
1. Patient was instructed to Apply local cold fermentation intermittently
for first 12 hours after the surgery ,
2. Instructed to only take cold diet for 24 hours.
3. Advice Amoxicillin 500 mg T.I.D coverage was to continue for 3 days.
4. Careful brushing in the area of surgery was advised against for the 1st
5. Check up was scheduled for the next day.
Post operative Instructions
6. Do not prescribe NSAID’s like Ibuprofen after surgery , because
they can inhibit the production of prostaglandin hormone in the body.
Prostaglandin is derived from Arachdonic acid through cyclooxygenase
PG has Properties of stimulating osteoclasts and sometimes osteoblasts,
which produce bone resorption through RANKL receptor.
So, adminstration of NSAID’s , inhibits the cyclooxygenase , results in
slow down the bone growth process which is Non vital to PAOO.
So Narcotic pain killers are prescribed .
The placement of orthodontic brackets and activation of the arch wires
are typically done one week before the surgical aspect of PAOO is
performed. However, if complex mucogingival procedures are combined
with the PAOO surgery, the lack of fixed orthodontic appliances may
enable easier flap manipulation and suturing.
After flap repositioning, an Immediate heavy Orthodontic forces are
applied to the teeth and in all cases initiation of orthodontic force should
not be delayed more than 2 weeks after surgery. A longer delay will fail
to take full advantage of the limited time period that the RAP is occurring.
Timing of orthodontic treatment
Depending on case braces are put for 3 to 9 months. After the braces are
removed , a retainer for at least 6 months is usually recommended. The
same types of braces and retainers are used in PAOO as in traditional
orthodontics , so you will have choice of metal or ceramic brackets.
Complications and side effects
It is less invasive procedure than osteotomy assisted orthodontics
or surgically assisted rapid expansion, but there have still been several
reports regarding adverse effects to the periodontium after
corticotomy, they are ranging from
1. No problems to slight interdental bone loss.
2. Loss of Attached gingiva.
3.Periodontal defects observed in some cases with short interdental
4. Subcutaneous hematomas of the face and the neck have been
reported after intensive corticotomies .
5.Some post-operative swelling and pain is expected for several days.
6. No effect on the vitality of the pulps of the teeth in the area of
corticotomy was reported . 69
Fischer in a sample of 6 patients with bilateral palatally impacted
maxillary canines requiring surgical exposure, randomly performed
corticotomy procedures on one side, in addition to the surgical exposure.
The corticotomy consisted of circular holes mesial and distal to the
impacted tooth, approximately 2mm and 60g of force was utilised
with 4-6week intervals between appointments.
The reduction in treatment time was between 28-33% for the corticotomy-
assisted canines Vs the non- corticotomy canines, with significantly higher
tooth movement velocities (1.06mm/month Vs 0.75mm/month).
Germec et al(2006) described case report of a bimaxillary protrusive
case being treated with their “ modified corticotomy ” approach. They
performed this mid-treatment, to accelerate the treatment. The
corticotomy procedure consisted of vertical cuts with a 0.5mm round
bur 2mm into bone. There were no horizontal cuts or lingual cuts.
Maxillary and mandibular 0.016 x 0.022 inch stainless steel retraction
arches with T loops were inserted 1 week before corticotomy.
In this case report, the total orthodontic treatment time (16 months) was
dramatically reduced when compared with the average treatment time for
extraction therapy (31 months).
Ozlem Aylikci, Caglar Sakin (2013)described case report of
piezoincision assisted canine distalisation in 1st premolar extraction
After leveling phase(0.016) finished, 0.016 stainless steel wire placed
and canine distalisation phase was started.
Vertical interproximal incisions were made, 5 mm apical to the
mesial and distal interdental papilla of related canines, on the
buccal aspect of each jaw using surgical blade No. 15. Incisions were
extending 10 mm length apically.
A Piezo surgical knife was used to create the cortical bone incision
through the gingival opening to a depth of approximately 4 mm.
Then , canine distalization was performed immediately using sentalloy
closed coil springs which produce 180 grams continuous forces to
maxillary canines. Closed coil springs were extending from the hook of
canine bracket to ipsilateral miniscrew.
Canine distalization phase completed within 4-5 months (classical
method it takes 4-8months).
Aljhani and Aldrees (2009) demonstrated treatment of an anterior
openbite with corticotomy procedure.
The patient was a 22-year-old woman with class I molar relation and
6mm anterior open bite and flared and spaced upper and lower
One week before the surgery, preadjusted edgewise orthodontic fixed
appliances were placed and 0.016 inch NiTi archwires were inserted for
leveling and alignment.
Full thickness flap was reflected both facially and lingually around all
erupted teeth from first molar to first molar in the maxillary arch and
between the canines in the mandibular arch .
The lingual interdental papilla between the maxillary central incisors was
not reflected and no vertical releasing incisions were used.
Cuts in the alveolus that penetrate the entire thickness of the cortical
plate both buccally and lingually around all the teeth in both arches.
Vertical decortication cuts were made between the roots of the teeth
and they were stopped 2–3 mm short of the alveolar crest.
Horizontal scalloped corticotomy cuts were used to connect the
vertical cuts along with perforations in the cortical plate.
0.016 x 0.022 inch NiTi archwire was inserted in the upper arch and 0.016
inch Stainless steel was inserted in the lower arch with 150 g NiTi coil
springs attached from the mandibular first molars to the canines for
retraction and powerchain to derotate the lower first Premolars.
Four weeks later, continuous powerchian was inserted in the upper arch
and a 0.016 x 0.016 inch stainless steel archwire with closing loops was
inserted in the lower arch for incisors retraction . Class III box elastics
(3/16 in., 4 oz) were prescribed to be worn full-time.
Four weeks later 0.016 x 0.022-in. stainless steel archwire was
inserted in the upper arch, and in the lower 0.016 inch stainless steel
with helices was inserted . Powerchains were replaced every 2 weeks,
and then finishing upper and lower 0.016 x 0.022 inch stainless steel
archwires were inserted and vertical anterior and posterior elastics were
The total active treatment period was only 5 months.
Corticotomy assisted orthodontics is an effective and reliable technique
to treat severe malocclusions to reduce the treatment time and increase
the treatment quality .
Reduced root resorption, increased alveolar volume, reduced chair side
time are the basic advantages of this technique. However this should be
carefully performed over the teeth and surrounding tissues to avoid the
risk of devitalisation of the teeth and periodontal damage.
The PAOO technique can be an especially attractive treatment option
and be a “win-win” situation for the orthodontist, the periodontist and
A long term follow up studies have to be performed to evaluate the
effects of corticotomy assisted orthodontics on retention and