Introduction
Nowadays there is an increased demand of orthodontic treatment especially among adult patients.Fixed orthodontic treatment lasts for 12-24 months with a variable retention period.So main concern of the patients is longer duration which in turn may lead to other complications such as periodontal problems,caries,root resorption as well as patient compliance.Clinicians are constantly striving towards developing strategies to enhance the rate of orthodontic tooth movement as it is very challenging to reduce the duration of orthodontic treatment.
A number of attempts have been made to create different approaches in order to achieve quicker results like biological, physical, biomechanical and surgical. One of such attempt is accelerated orthodontics. It reduces treatment time, enhances expansion and increased traction of impacted teeth and provide more orthodontic stability.
History
In 1892,it was defined as a technique involving linear cuts in the cortical plates surrounding teeth for their mobilization.Kole et al in 1959[1] gave the concept of corticotomy combined with orthodontics for reducing treatment time.Similar attempts were made by Gantes etS10;al in five adult patients in whom space closing was attempted with orthodontic forces following alveolar corticotomy.The term Wilckodontics or (AOO)-accelerated osteogenic orthodontics or( PAOO)- periodontally accelerated osteogenic orthodontics was coined by Wilcko et al[1]S09;.Their technique involved selective decortication in the form of lines and points over teeth to be moved.A resorbable bone graft is placed over the surgical sites to augment the confining bone during tooth movement.When healing is done after two weeks, orthodontic tooth movement is started.Grafts prevent complications like fenestrations and dehiscences.This mechanism was explained by Harold Frost as Regional Acceleratory Phenomenon. Sebaoun et al explained the histological mechanism following corticotomy using a rat model.
Methods to accelerate tooth movement:-
It can be studied under following categories:
1.Surgical
2.Non-surgical
1.Surgical approach:
The surgical technique is an effective technique used for adult patients where duration of orthodontic treatment is critical.Several surgical approaches that have been tried were interseptal alveolar surgery,osteotomy,corticotomy and piezocision .
a) Interseptal alveolar surgery
Interseptal alveolar surgery or distraction osteogenesis can be of further two types:distraction of dentoalveolar bone or distraction of PDL.
Dentoalveolar distraction:-
This method is based on the principle of distraction osteogenesis. In this method, corticotomy is done on the alveolar side, sparing the palatal side so that blood flow is maintained.More dissection and osteotomies are performed at the vestibule[11].
Distraction of PDL:-
Lion et al suggested distraction of PDLS12;.They conducted a clinical experiment in which rapid distalization of 26 canine teeth was carried out using distraction of PDL. This technique was referred to as dental distraction.It is carried out in premolar extraction cases where interseptal bone distal to canine is undermined with bur.Canines can be distalized upto 6 mm in the extraction space using customized distracters during a short period of 3 weeks.
Both techniques accelerated tooth movement with no evidence of significant root resorption, ankylosis and root fracture, however there were some contradictory results regarding electrical vitality test of the retracted canines.
b) Corticotomy and osteotomy:
Corticotomy is a surgical procedure in which cortical bone is cut and perforated,reducing the resistance of the cortical bone, accelerating tooth movement[12]. This can be followed by placement of a graft material whenever required to augment thickness of bone.In 2001,Wilcko et al reported that a surface- computed tomographic evaluation of corticotomized patients showed a transient localized demineralization-remineralization process consistent with the accelerated wound healing pattern of the regional acceleratory phenomenon[13]. Although it has been proven successfully by many authors to accelerate tooth movement,this method had its shortcoming involving dizziness in the patients and postoperative pain, swelling, chances of infection, avascular necrosis etc.
c)Piezocision:
It is one of the latest techniques.Dibart[1] S11;was among the first to apply this technique in which primary incision is placed on the buccal gingiva followed by incisions by Piezosurgical knife to the buccal cortex. This technique didnot cause any periodontal damage as reported by Hassan. Also it can be used with Invisalign, leading to better aesthetic appearance and less treatment time(Kesar)
d)Alvceocentesis:
Alveocentesis which means 'puncturing bone' is a microinvasive technique developed by Propel Orthodontics[1] S12;.This technique stimulates cytokine activity thereby accelerating alveolar bone remodeling. The result is 50-60% faster movement as compare to traditional orthodontics. Propel can be completed chair-side in minutes and doesnot require any advanced surgical training. This device comes as ready to use sterile disposable device. It has an adjustable depth dial and indicating arrow on the driver body. The adjustable depth dial can be positioned to 0mm,3mm,5mm and 7mm of tip depth. Animal studies have shown that by performing micro-osteoperforations on alveolar bone during orthodontic tooth movement,stimulates the expression of inflammatory markers leading to increase in osteoclast activity and the rate of tooth movement.
Non-surgical approach
A number of non-surgical methods such as use of devices,vibratory methods,electromagnetic fields and biological methods have been developed.Although these provide accelerated tooth movement,these methods are limited to few case reports and have not supported by clinical trials,thus limited application.
a)Vibratory forces:
Nishimura et al evaluated the effect of vibratory forces on rate of orthodontic tooth movement in maxillary molars of wistar rats[1] S10;.Greater tooth movement was observed in exprimental groups as compare to conventional groups. A device has been developed to accelerate tooth movement,on the basis of vibratory cyclical forces. It has been found that applying vibrations for different duration per day accelerate tooth movement between 15% and 30% in animal experiments. This procedure didnot lead to root resorption.
b) Direct electric current and pulsed electromagnetic fields:
Electric current can be used to accelerate tooth movement. This technique was tested on animals by applying direct current to the anode at the pressure sites and cathode at the tension sites thus generating local responses as shown by group of investigators[2]. However the bulkiness of devices and the source of electricity made it difficult to be tested clinically. Pulsed electromagnetic fields are produced by an integrated circuit embedded in a removable dentureS08;.
c)Photobiomodulation (LLLT):
Photobiomodulation or low level laser therapy is used in the form of near infrared light with specific wavelength and intensity[1] S13;.This light leads to an increase in ATP at a localized site which induces cells to undergo a remodelling process due to an elevated metabolic activity. During tooth movement, higher ATP leads to rapid turnover of cells resulting in accelerated tooth movement and activation of Cytochrome C. It also increases the vascular activity which contributes to rapid turnover of bone leading to proliferation of osteoclast, osteoblast and fibroblasts .A number of human trials have been conducted using low intensity diode laser which showed increased rate of tooth movement. Laser wavelength of 800nm and output power of 0.25 mw have indicated significant stimulation of bone metabolism, rapid ossification and acceleration of tooth movement to 1.5 fold in rat experiments.
d)Biological methods:
Effect of cytokines and prostaglandins:-
Factors such as RANKL, prostaglandins, vascular endothelial factors have been tested in various experimental models. An increased rate of tooth movement has been seen in animals on exogenous administration of prostaglandins[3]. It has a direct action on osteoclasts in increasing their numbers and their capacity to form a ruffled border and effect bone resorption. It also stimulates osteoblastic cell differentiation and new bone formation.Human trials conducted showed greater tooth movement in extraction cases when prostaglandin was administered. RANKL is a membrane bound protein on the osteoblasts that bind to the RANK on the osteoclasts and causes osteoclastogenesis.OPG(a decay receptor) produced by osteoblastic cells compete with RANK for RANKL binding.Bone remodelling is controlled by a balance between RANK-RANKL binding and OPG production. A balanced delivery of genes such as RANKL and OPG to the oral tissues is beneficial in managing the rate of orthodontic treatment.
Effect of Vitamin D3,PTH and Relaxin
1,25 dihydroxycholecalciferol (a hormonal form of vitamin D) also plays a role in the acceleration of tooth movement. An experiment was conducted in which vitamin D metabolite was injected on the PDL of cats for several weeksS09;.It accelerated tooth movement at 60% more than the control group due to increase of osteoclasts on the pressure site.
Studies have shown that locally injected PTH induced local bone resorption and accelerate orthodontic tooth movement on ratsS13;.Use of relaxin hormone has also been investigated[1] S04;.This hormone helps during childbirth as it widens pubic ligaments in females. It is suggested to be present in cranial suture and PDL. It remodels soft tissue. During orthodontic tooth movement it increases collagen in the tension site and decreases it in compression site. Studies conducted on rats shown that it accelerates orthodontic tooth movement.
Conclusion
Since long, orthodontists are looking for ways to efficiently treat more patients in shorter treatment times. Reducing treatment time for patients has been an industry goal due to patient and orthodontist demand. Wickodontics is a solution to such problem.Current methods such as piezocision, alveocentesis, lasers and vibrations have reduced the invasive nature of previous procedures. Although these techniques had drawbacks that made them not commonly used clinicaly, however there has been a rapid increase in interest of product companies to enhance the effects of biology in orthodontics
References:
1. Kole H.Surgical operations on the alveolar ridge to correct occlusal abnormalities.Oral Scie.Oral Med.Oral Pathol.1959;12(5):515-29.
2. Davidovitch Z,Finkelson M.D.,Steigman S.,Shanfeld J.L.,Montgomery P.C.,Korostaff E.Electric currents,bone remodeling and orthodontic tooth movement II.Increase in rate of tooth movement and periodontal cyclic nucleotide levels by combined force and electric current.Am J Orthod.1980 Jan;77(1):33-47.
3. Yamasaki K.,Shibuta Y.,Imai S.,Tani Y.,Shibasaki Y.,Fukuhara T.Clinical application of prostaglandin E1(PGE1) upon orthodontic tooth movement.Am.J Orthod.1984;85:508-515.
4. Stark T.M.,Sinclair P.M.The effect of pulsed electromagnetic fields on orthodontic tooth movement.Am J Orthod 1987;91:97-104.
5. Collins M.K.,Sinclair P.M.The local use of vitamin D to increase the rate of orthodontic tooth movement.Am J Orthod Dentofacial Orthop.1988;94(4):278-84
6. Gantes B.,Rathbun E.,Anholm M.Effects on the periodontium following corticotomy facilitated orthodontics:Case reports.J Periodontal 1990;61:234-8.
7. Uematsu S.,Mogi M.,Deguchi T.Interleukin (IL)-1 beta,IL-6,tumor necrosis factor.alpha epidermal growth factor and beta 2-microglobulin levels are elevatedin gingival crevicular fluid during human orthodontic tooth movement.J Dent Res 1996;75:562-7.
8. Liou E.J.W.,C.S.Huang.Rapid canine retraction through distraction of the periodontal ligament.Am J Orthod Dentofacial Orthop 1998;114:372-382.
9. Soma S.,Matsumoto S.,Higuchi Y.,Takano-Yamamoto T.,Yamashita K.,Kurisu K.,Iwamoto M.Local and chronic application of PTH accelerates tooth movement in rats.J Dent Res.2000;79(9):1717-24.
10. NicozisisJ.L.,Nah-Cederquist H.D.,Tuncay O.C.Relaxin affects the dentofacial sutural tissues.Clin Orthod Res.2000;3(4):192-201.
11. Kisnisci R.S.,Iseri H.,Tuz H.H.,Altug A.T.Dentoalveolar distraction osteogenesis for rapid orthodontic canine retraction.J Oral Maxillofac Sci.2002;60(4):389-94.
12. Park Y.G.,Kang S.G.,Kim S.J.Accelerated tooth movement by corticision as osseous orthodontic paradigm.Kinki Tokai Kyosei Shika Gakkai Gakujyutsu taiki Sokai 2006;46:6.
13. Ferguson D.J.,W.M.Wilcko,M.T.Wilcko 2006.Selective alveolar decortication for rapid surgical orthodontic resolution of skeletal malocclusion.
14. Garlet T.P.,Coelho U.,Silva J.S.,Garlet G.P.Cytokine expression pattern in compression and tension sides of theperiodontal ligament during orthodontic tooth movement in humans.Eur J Oral Sci.2007;115:355-62.
15. Wicko M.T.,WilckoW.M.,Nabil F.Bissada.An evidence based analysis of periodontally accelerated orthodontics and osteogenic technique:a synthesisof scientific perspectives.Semin Orthod 2008;14:305-16.
16. Nishimura M.,Chiba M.,Ohashi T.,Sato M.,Shimizu Y.,Igarashi K.,Mitani H.Periodontal tissue activation by vibration:intermittent stimulation by resonance vibration accelerates experimental tooth movement in rats.Am J Orthod Dentofacial Orthop.2008;133(4):572-83
17. Dibart S.,Sebaoun J.D.,SurmenianJ.Piezocision:a minimally invasive ,periodontally accelerated orthodontic tooth movement procedure.Compend Contin Educ Dent.2009.Jul-Aug;30(6):342-346,348-50.
18. Nicozisis J.Accelerated Orthodontics with alveocentesis.Princeton Orthodontics.Dec 19,2012
19. Kau CCK.,Kantarci A.,Shaughnessy T.,Vachiramon A.,Santiwong P.,Fuente A.,Skrenes D.,Ma D.,Brawn P.Photobiomodulation accelerates orthodontic alignment in the early phase of treatment.Progress in orthodontics 2013,14:30
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