Bone block technique (Köle 1959)

In 1959 Heinrich Köle introduced the description of a corticotomy technique associated to orthodontic treatment to accelerate dental movement under the theory of bone block movements.⁵ He proposed that tooth movement could be achieved in shorter time if interdental and osteotomies cuts were performed, since cortical bone represented greater resistance to tooth movement, and thus, if cortical bone continuity was altered, tooth movements could be achieved in shorter time.⁵

This surgical technique consisted on raising a muco-periosteal flap (from a vestibular and lingual/ palatal direction), and conduct osteotomies in inter-radicular and supra-apical sites. Cuts should measure 10 mm and be located above all apexes; a perpendicular (horizontal) cut should be undertaken, achieving thus separation of small-sized bone blocks to provide acceleration of orthodontic movement (Figure 1).⁴ It is important to point out that most movements described by Köle were movements conducted with orthopedic forces applied through removable devices adapted by adjustable screws. Since this technique was highly invasive it garnered little acceptation.^{2 4}

Figure 1  Bone block Köle osteotomies. 

The advantage of this technique was that it provided faster tooth movement in shorter time (approximately 6 to 12 weeks). This procedure was recommended for separation of single or grouped teeth, it was used to achieve distally-oriented movements after an extraction (Figure 2).⁴

Figure 2 Separation of small bone blocks per dental unit. 

Fast orthodontics (Chung 1975 and 1978)

A new technique called Fast Orthodontics was proposed by Chung between 1975 and 1978. This technique combined cuts with orthopedic forces exerted with intra-osseous anchoring devices which normally were mini-plates or implants. The surgical cut had a «C» shape and biologically attempted to generate compression-osteogenesis in the osteotomized segment (Figures 3 and 4).⁴ Correction of anterior protrusion with or without open bite was among suggested indications.⁶

Figure 3 Chung's perisegmental osteotomy. 

Figure 4  Chung's osteotomy design with intra-osseous anchorage devices. 

Disadvantages of this technique were its invasive nature,⁴ and the fact that osteotomies were performed at different surgical times with lapses of 2 to 3 weeks separating them.⁶

Limitations for this technique were the sort of removable devices used at the time which were insufficient to provide required forces after were insufficient to provide required forces after corticotomies procedures; said forces were the key factor to achieve treatment success.⁵

The aforementioned techniques were considered very aggressive and invasive, therefore, several authors began their modification, exchanging osteotomies for corticotomies; since osteotomy consists on performing surgical incisions through cortical bone transgressing medullar bone and corticotomy is the surgical technique in which only cortical bone is cut, perforated or mechanically altered until reaching medullar bone, which remains intact.²

Selective alveolar technique

In 1978, Generson modified Köle's technique by replacing supra-apical osteotomy for supra-apical corticotomy;² he described a method of open bite treatment using selective alveolar corticotomy in conjunction with orthodontic treatment (Figures 5 and 6).⁴

Figure 5  Selective alveolar corticotomy. 

Figure 6  Selective alveolar corticotomy. 

Figure 6 shows vertical cuts only performed in vestibular cortical bone; joined with horizontal corticotomy (supra-apical); penetration in the thinnest cortical bone can be observed.

Up to this moment it was considered that accelerated dental movement could be due to an individualized displacement of the bone segment.³

Accelerated osteogenic orthodontics, AOO (Wilcko 2001)

In 2001, Wilcko reported two cases of corticotomy treated patients assessed through computerized tomography. In that study he proposed that speed of dental movement is due to local and transitory demineralization and re-mineralization in the alveolar bone which was compatible with regional acelerated phenomenon (RAP). This phenomenon was first described by the orthopedist H Frost in 1983, he showed that the design of the corticotomy was not responsible for accelerated dental movement, since this movement was caused by the degree of metabolic alteration. Wilcko's AOO technique required palatal and vestibular approach with de-corticalization, using rotary systems and orthodontic appliances. Although yielding suitable results, this technique is considered invasive.²

The most important advantages of the AOO technique are the decrease of dental movement limits as well as avoidance of extractions.

The Wilcko brothers modified their AOO technique by incorporating bone graft to the aforementioned «osseous activity» in order to increase alveolar bone. This technique was renamed «periodontally accelerated osteogenic orthodontics» (PAOO), the comprehensive procedure was recorded as Wilckodontics (Figure 7).⁴

Figure 7 Corticotomy technique (PAOO). 

Periodontically accelerated osteogenic orthodontics (PAOO), (Wilcko 2001)

This technique, proposed in 2001 by the orthodontist and periodontist Wilcko brothers is executed in three surgical phases.⁴

First phase: selective alveolar decortization was conducted, and a total thickness (muco-periosteal) flap was raised.² Vertical corticotomies were executed in inter-radicular spaces, (vestibular/lingual/palatal) with a number 1 round burr, preserving a distance of 2-3 mm to the osseous crest and exceeding by 2 mm the dental apex.² According to each case, vertical corticotomies were linked to semi-circular corticotomies in the upper or lower portion of the apex (Figure 8).⁴ After this, 0.5 mm deep perforations were undertaken on the root of the tooth with a round burr. These perforations were limited to vestibular and lingual cortical bone and had the aim of providing maximum bleeding (Figure 9).⁴ This technique recommends to locate perforations in the thickest areas of cortical bone, following dental root morphology.⁴

Figure 8  Link of inter-radicular vertical corticotomies with semi-circular cortcotomies at the apical third. 

Figure 9  Perforations on the root of the tooth. 

Second phase: consists on following alveolar increase procedures by placing bone graft material. Decalcified matrixes stimulate osteoblastic activity (Figure 10), thus, after procedure, alveolar volume increase is achieved. Flaps are sutured with 4-0 silk or 5-0 Gortex; sutures are removed 2 or 3 weeks later, depending on post-surgical assessment.⁴

Figure 10 Bone graft placement. 

Third phase: It consists on application of orthodontics forces every two weeks. It is recommended to place appliances one week before corticotomy, although they can be placed 2 to 3 weeks after surgery so as to facilitate surgical procedure (Figure 11). Orthodontic activations can be conducted every two weeks. Movement rate achieved with this technique is 1-2 mm per week, in comparison with the single monthly millimeter achieved with a conventional orthodontic treatment.⁴

Figure 11  Placement of appliances is recommended one week before corticotomy. 

Advantages of this technique are the following: excellent visibility to execute procedure, possibility of achieving corticotomies with electrical scalpel or burr,^{2 4} treatment time decrease,⁴ faster dental movements, lacking associated root resorption or pulp lesion in teeth subjected to dental movement¹³ accelerated canine retraction after premolar extraction.^{13 14} Execution of alveolar increase and remodeling (covering with bone graft) improves gingival esthetics.⁴ Disadvantages of this technique are prolonged surgical time as well as tissue inflammation proportional to treatment, ecchymosis and pain.²

Modified corticotomy technique

Germec published an article in 2006 where he presented his modified corticotomy technique. This technique significantly reduced surgical procedure time; it is a mono-cortical technique eliciting no negative effect in periodontal tissues, preserving as well pulp vitality of treated teeth. One week before undertaking surgery, it is recommended to stabilize upper and lower arches with 0.016″ x 0.022″ stainless steel arches.¹⁵

The main indication to use this technique is in patients with difficult lingual or palatal surgical access. Its greatest advantage lies in elimination of palatal or lingual flaps, as well as cuts in the cortical bone at the site; this results in surgical time decrease and thus greater comfort and lesser stress for the patient.¹⁵

Infiltrative local anesthesia is used in this surgical technique; a mucoperiosteal flap is raised from a vestibular direction, under dental apexes. Vertical cuts must be achieved with a low speed, 0.5 mm diameter stainless steel round burr, from the gingival margin up to 2 or 3 mm underneath dental apexes, with a 1.5 to 2 mm depth on the cortical bone (Figure 12).¹⁵

Figure 12  Germec modified corticotomy. 

Monocortical technique for dental dislocation and periodontal ligament distraction proposed by Vercelloti and Podesta (MTDLD)

In 2007, Vercelloti and Podesta proposed a vestibular approach corticotomy procedure executed with electrical hand-piece. This technique was called monocortical technique for dental dislocation and periodontal ligament distraction (MTDLD).

It was initially developed through dental pressure which caused periodontal compression, where there was rapid root (dislocation) and bone cortical unit movement without eliciting periodontal ligament compression or bone resorption (MTD), after this follows a rapid distraction of the periodontal ligament (LD) to culminate in an osteogenic healing process.

This technique arose due to a desire to maximize dental movement speed, preventing thus periodontal tissue damage. Since cuts are executed with an electrical scalpel, which due to mitochondrial activation and cell reproductive capacity offers the advantage of causing minimum morbidity, rapid tissue regeneration and minimal damage are elicited.4 Stages for this technique are similar to those described by the Wilcko brothers, but with the difference of being conducted in a mono-cortical manner, and with an alveolar crest modification where «Y» shaped cuts are performed in order to preserve the alveolar crest.

During surgery, 0.5 mm -deep longitudinal inter- proximal cuts are performed in the vestibular cortical bone, one horizontal incision of same depth is equally performed at 1-2 mm above apexes, said incision is completed in a «Y» shape (Figure 13).⁴

Figure 13  Illustration of «Y» shaped cuts to preserve alveolar crest. 

Alveolar increases are undertaken in selected cases where vestibular cortical bone thickness increase is required; this increase is achieved with autologous bone harvesting in the shape of chips from alveolar bone apical zone or through a 0.21-1 mm sliver of Bio-Oss^®, in which case the graft is lined with BioGide^® resorbable collagen membrane. With respect to orthodontic forces application it is preferred to immediately place appliances once corticotomies have been completed, so as to facilitate surgical procedures.

It is recommended to initiate force application from one to seven days after surgery completion, keeping activation rhythm every two weeks. It is advisable to examine the patient every week so as to avoid appearance of interferences which could block dental movement.⁴

This technique is recommended for over-erupted teeth and to faster achieve retained canine exposition. Advantages of this technique are that it is minimally invasive and less traumatic, and the fact of performing «Y» shaped incisions preserves the alveolar crest.⁴

Piezocision technique¹ (Dibart 2009)

In 2009 Dibart published a trans-mucosal corticotomy technique called piezocision. It is considered less invasive than the others while providing the same results. It decreases orthodontic treatment time in patients with reduced or intact periodontium, and achieves better results with less aggressive procedures.

In this surgical technique, vertical mini-incisions are performed with a number 15 scalpel micro-blade in vestibular inter-radicular spaces located from the base of the papilla, after this, trans-mucosal corticotomies are performed through previously executed incisions, at a 2 to 3 mm depth. It is not necessary to suture unless there was previous tunnel-building for bone implant placement. Orthodontic forces are applied every 14 days (Figure 14).

Figure 14  Vertical micro-incisions in vestibular inter- radicular spaces from the papilla base. 

The advantage of this technique is that it is minimally traumatic, therefore post-surgical presence of pain, inflammation and ecchymosis is infrequent, since no full-thickness flap was previously raised^{1 2} and surgical time was short. This technique decreases damage to osteocytes and allows bone cell survival.¹ One of the most important advantages of this technique is that the use of electrical scalpel, due to its micro-vibration, allows selective cutting of mineralized structures without damaging soft tissues. This is due to ultrasonic vibrations of 29 kHz frequency and 60/200 Hz range. Micro-metric vibration guarantees precise cutting (Figure 15).¹ This technique suffers the disadvantage of allowing poor visibility, unavoidably requiring electrical scalpel use, and diffi culties inherent to control bone graft.²

Figure 15 Trans-mucosal corticotomies through incisions previously achieved with electrical scalpel.. 

Technique for intrusion of molars with maxillary splint (Oliveira 2010)

In 2010, Oliveira published an article where he described a combination of alveolar corticotomy with a modified maxillary splint with nickel-titanium spring. The aim of this technique was to intrude over-erupted molars (Figure 16).⁷

Figure 16  Maxillary modified splint with Nickel-Titanium spring. 

Oliveira reported that in one patient, 4 mm intrusion was achieved in 2.5 months, and in another patient, 3 to 4 mm intrusion was accomplished in 4 months.⁷ This technique is used in adult or young patients with healthy or reduced periodontium; it facilitates bi-maxillary protrusion correction, closure of skeletal open bite, intrusion of molar with removable appliances and treatment of patients with cleft lip and palate.

In the surgical technique, a full-thickness flap is raised from a vestibular, palatal or lingual approach, on the area where dental movement is to be conducted. After this, vertical corticotomies are performed with a round 701 burr in inter-radicular spaces 2 mm away from the alveolar crest and surpassing by 2 or 3 mm dental apexes, care must be exerted to barely touch medullar bone. At this height, horizontal corticotomies are performed to link vertical corticotomies (Figure 17).

Figure 17  Corticotomy executed in the molar to be intruded, to later place a nickel-titanium spring.. 

Once the aforementioned is completed, the flap is repositioned and sutured, placed on a modified acrylic splint, and leaving uncovered the occlusal aspect of the molar to be intruded. Seven days later orthodontic forces are applied, and after this, forces are applied every 14 days until desired intrusion is achieved (Figure 18).⁷

Figure 18  Inter-consultation with orthodontics specialist from beginning of treatment until achieving molar intrusion.. 

Advantages of this technique are the following: it facilitates difficult orthodontic movements, allows for significant transversal and anterior-posterior dental expansion, corrects moderate to severe skeletal malocclusions, and provides clinical results twice or three times faster when compared to conventional orthodontic treatment.⁷

Minimally invasive procedure conducted with endoscopy-assisted tunnel⁶ (2012)

This technique was published in 2012. It can be considered the most conservative technique when compared with others; it decreases trauma to periodontal tissues during trans-surgical periods and post-operative discomfort, as well as surgical time since it can be accomplished in about 26 minutes.

This technique was first described in 2010. Computed tomography (Cone-Beam) will be needed in order to consider a patient as a possible candidate. Criteria to take into account are the following: Teeth to be moved and anchorage teeth, periodontal circumstances, root position and morphology as well as width of cortical bone.

Advantages of this technique are: decrease of surgical time, periodontium preservation, since it is not required to raise a muco-periosteal flap, patient's easy acceptance of the technique, maximum decrease of post-surgery inflammation since the technique is performed only in the upper or lower anterior section.⁶

In order to execute this technique, a 5-10 mm full-thickness vertical incision is performed from a vestibular approach at the upper midline to treat the anterior segment, or behind the upper canine in cases when the posterior segment is to be treated. A sub- periosteal dissection is performed on the roots of the teeth with a sharp periosteal elevator (Figure 19A), a full thickness vertical incision is performed from a vestibular approach on the midline (Figure 19B). A «tunnel» sub-periosteal dissection is performed.

Figures 19A and B Vestibular approach with 5 to 10mm full thickness incision. 

After this, an electrical micro-saw is introduced into the created tunnel and vertical corticotomies are executed from a vestibular approach following the length of the root, without touching the alveolar crest (Figures 19C and D).⁶

Figures 19C and D Surgical procedure with electrical micro-saw. 

With the help of an endoscope through 1.9 mm optic fiber it is possible to control cuts on cortical bone, when the saw reaches cancellous matter, bleeding can be observed by means of the endoscope (Figure 20).⁶

Figure 20  Close-up with endoscope to assess bleeding. 

If resistance is met by the micro-saw, it means that it was placed on root surfaces, therefore, direction of cuts must be changed. Computerized tomography is used to assess corticotomy depth. Lastly, incisions are uninterruptedly sutured with 5-0 polyglactine (Figure 21).⁶

Figure 21  Incision suture. 

This technique is presented as the most conservative. Small incisions are performed with the piezoelectrico in the cortical bone. Number of incisions will depend on amount and placement of teeth in the quadrant to be treated. Light afforded by the endoscope and wider image are important advantages as well as achieving better control in root position.