biology of tooth movement ii

TOOTH MOVEMENT

Force Application

Elimination

Effects of Force

On bone and teeth

Tension Bone Formation Osteoblasts

Compression Bone Resorption Osteoclasts

Magnitude of Force

> 7-8 grams

Duration of Force

> 4-6 hours

Types of Forces

Continuous

Light sustained forces from NiTi wires and springs

Interrupted

A wire that gets deactivated between appointments

Intermittent

Removable appliances

Effects of Drugs on Orthodontic Tooth

Movement

STEROIDS

NSAIDS

Relaxin

Pregnancy Hormones

Destroyes Collagen

Helps in softening / dilatation of cervix

Increased rate of Orthodontic Tooth Movement

Prostaglandin Inhibitors

NSAIDS

STEROIDS

Slow down tooth movement

Paracetamol

COX 3 Inhibitor

Analgesic

Antipyretic

But not anti-inflammatory

Does not effect the rate of tooth movement

Other drugs

Tricyclic Antidepressants

Antiarrythmic agents

Antimalarials

Phenytoin

Statins

Tetracyclines

Osteoporosis

Estrogen Replacement Therapy

Reduced production of PG and IL-1 and IL-6

Reduced rate of remodeling

ESTROGEN – Uterine Cancers

ESTROGEN + PROGESTERONE – Breast Cancers

Estrogen Receptor Modulator (Anti-cancer?)

Raloxifine

Tamoxifine

Bisphosphonates

BISPHOSPHONATES

Can be

Nitrogenous

Non-nitrogenous

Binds to Hydroxyapatite

Slows down tooth movement

Long half life

In months and years

Bisphosphonates

Risks Involved

Osteonecrosis

Slow tooth movement

A challenging task?

Benefits of reduced treatment time

Risks involved

ENHANCING ORTHODONITC TOOTH MOVEMENT

Biomechanical approach

Physiological/mechanical approach

Pharmacological approach

Surgical-assisted approach

Surgery-simulated approach

METHODS OF ENHANCHING TOOTH MOVEMENT

Self-ligating brackets:

Frictional force of ligatures ( O configuration)= 50 g Reduced friction- especially passive design Less force - more physiological More alveolar bone generation, greater expansion, less

proclination of anterior teeth, less need for extractions

Kapur et al: Friction per bracket

with Ni-Ti archwires 41g (conventional) 15g (self ligating)

For SS wires: 61g (conventional) 3.6g (self ligating)

BIOMECHANICAL APPROACH

Self-ligating brackets:

Despite low friction, do not perform faster alignment/ space

closure

Narrower than conventional brackets – More Tipping – More

Binding

Short chair side time and less incisor proclination (1.5 degree)

1. Chen SS et al. Systemic review of self ligating brackets. Am J Orthod DentofacialOrthop.2010;137:726e1:726e18.

2. Fleming PS, Johal A. Self ligating brackets in orthodontics. A systemic review. AngleOrthod.2010;80:575-84.

BIOMECHANICAL APPROACH

Direct Electric Current Stimulation:

Direct current : 7 volts & 15 microamperes

Anode : Pressure side; Cathode: tension side

More bone formation and resorption at electrically treated sites

Increase osteoblasts, PDL cells, osteoclasts

Mechanism:

Direct current generate local response to increase alveolar bone turnover

Disadvantages:

The device and battery providing electric current are bulky

No clinical application has been reported1. Beesan DC, Jhonston LE, Wisotzky J. Effect of constant currents on orthodontic tooth movement

in cat. J Dent Res 1975;54:251-54

2. Davidovitch Z et al. Electric currents, bone remodelling and orthodontic tooth movment. Am JOrthod.1980;77:33-47

PHYSIOLOGICAL APPROACH

Endogenous Piezoelectric Stimulation

Electric potentials are created by force application

The charges are created when stress is applied and released

Vibration could be used to apply and release forces at rapid rate

Mechanism:

Stimulate cell proliferation and maturation to allow faster bone remodeling

AcceleDent vibratory system:

High frequency vibration (30Hz) for 20 min/day


Endogenous Piezoelectric Stimulation

Prospective RCT: 45 patient , Random allocation for use of AcceleDentappliance

NiTi coil spring was attached from canine and distally to TSAD

38% (0.29mm/wk) faster tooth movement compared to control (0.21mm/wk)

Discussion:

Lack of blinding & measurement method may affect the outcome

TSAD can drift under orthodontic loading-1.5mm

Vibration may results in accelerated drift of TSAD

AcceleDent website.http//accledent.com/images/uploads/AcceleDent + increases+theRate of Orthodontic tooth movement Results of a RCT Final for Print November 142011.pdf Accessed 20 May 2012


Low-Level Laser Therapy (LLLT):

Gallium-Aluminium-Arsenide Irradiation

Wavelength: 630-860 nm; Energy: 4.5-6 J/cm2

Minimally invasive, simple and safe to apply

Mechanism:

Increase in ATP at localized site - induce cells to undergo a remodeling process due to an elevated metabolic activity

Increase in vascular activity contribute to rapid turnover of bone

Evidence:

Few studies reported positive result, few no effect and some reported retarded tooth movement


Youssef M et al. Low energy laser irradiation therapy during orthodontic tooth movement. Apreliminary stud. Lasers Med Sci 2008;23:27-33

Limpanichkul et al. Effects of low laser therapy on rate of orthodontic tooth movement. OrthodCraniofac Res. 2006;9:38-43

Photo-biomodulation (Biolux) Light with 800-850nm wavelength

Penetrates cheeks and soft tissues over alveolar bone

97% light lost , 3% excite intracellular enzymes and increase cellular activity in PDL and bone

Increase blood flow and may enhance tooth movement

Advantage: Can be adjusted according to anchorage requirements


Corticosteroids

PG’s

Growth Hormone

Parathyroid hormone

Active form of Vitamin D

Relaxin

PHARMACOLOGICAL APPROACH

Prostglandins:

Mechanism:

PGE2 – an important mediator of bone remodeling under mechanical force

Increase cAMP and cGMP

Yamaseki & Harell et al:

Experiment on animal model found application of orthodontic force – increase in PG’s synthesis- stimulate osteoclastic bone resorption

Injections of PGE1 and PGE2 into gingival tissues near first molar – increase rate of tooth movement


Yamaseki K et al. Prostaglandin as a mediator of bone resoprtion induced by experimental tooth movement in monkeys. J Dent Res. 1982;61:1444-1446

Protaglandins:

Clinical application:

Following LA, 0.1 ml of a 0.01% PGE1 solution in saline was injected submucosally at pressure side

Rate of canine retraction- 1.6 fold increase

Disadvantages:

Injection were repeated at weakly intervals

Severe pain after injections


Speilmann T et al. Acceleration of orthodontically induced tooth movement through the local application of prostaglandin (PGE1). Schweiz Monatsschr Zahnmed 1989;99:162-165

Relaxin Insulin family of structurally related hormone

Produced during pregnancy

Mechanism: Increase rate of degradation of collagen (stimulate collagenase)

Increase bone resorption via increase in TNF and IL-1B secretion


Kristiansson P et al. Does human relaxin-2 affect peripheral blood mononuclear cells to increase inflammatory mediators in pathological bone loss?.Ann N Y Acad Sci.2005;1041:317-9

Stewart Dr et al. Use of Relaxin in orthodontics. Ann N Y Ascad Sci.2005 1041:379-387

Vitamin D ( 1,25 Dihydroxycholecalciferol)

Vitamin D and PTH regulate the amount of calcium and phosphorus levels

Vitamin D receptors – present on osteoblasts but also in osteoclast precursors and in active osteoclasts

Collins and Sinclair et al (1988)

Intraligamentary injections of vitamin D metabolite- increase in the number of osteoclasts and amount of tooth movement during canine retraction with light forces

Stimulatory action of vitamin D on osteoblasts can help stabilize orthodontic tooth movement


PDL Distraction

Rapid canine retraction through

distraction of dento-alveolus

Corticotomy assisted rapid tooth

movement

Corticision/Peizocision

SURGICAL-ASSISTED APPROACH

Rapid canine retraction via PDL distraction Mechanism:

Incorporation of a surgical cuts on interseptal bone distal to canine at the time of extraction of first premolar

Rapid canine retraction through distraction (stretching) of PDL

Pressure side: Canine-interseptal bone complex transported distally inside the socket

Tension side: PDL distraction leading to osteogenesis


PDL DISTRACTION

Procedure At the time of extraction of 1st pm,

socket is deepened to the samedepth as canine with a 4mmround carbide bur

Interseptal bone is reduced to 1.0-1.5mm

A custom made distractionappliance is deliveredimmediately after extraction

Rate of activation:

0.5mm-1mm/day

Liou EJ, Haung CS. Rapid canine retraction through distraction of periodontal ligament. Am J Orthod Dentofacial Orthop. 1998;114: 372-383

Dento-alveolar Distraction

Surgical Technique: Mucoperiosteal flap reflected

Cortical holes made in alveolar bone curving apically to pass 3-5mm from apex

Connect the holes with tapering fissure

Large osteotomes are used to mobilize the whole segment

Distraction: after 3 days of surgery

Activation of distractor: twice/day in morning and evening 0.8mm/day

Can also be used to bring ankylosed tooth into position

Disadvantage: Aggressive and complicated


Kisniscu RS et al. Dentoalveolar distraction osteogenesis for rapid canine retraction. J Oral MaxillfacSurgery 2002. 60:389-394

RAP

Increased rate of orthodontic tooth movement

Increased remodelling

Transient osteopenia

Regional Acceleratory Phenomenon

Corticotomy Assisted Tooth Movement Local injury to the alveolar process reduces resistance to tooth movement

and generate RAP

Indications: Resolve crowding and shorten treatment time

Accelerate canine retraction

Enhance post-orthodontic stability

Facilitate eruption of impacted teeth

Molar intrusion and open bite correction

Molar distalization

Kole’s technique: Flap raised, vertical cuts facially and lingually between and under teeth

that did not penetrate all the way (only cortex)


Wilcodontics Accelerated osteogenic orthdontics (AOO)

Periodontally accelerated osteogenic orthodontics (PAOO)

Technique: Full thickness flaps are reflected carefully beyond the apices to allow

decortication around apices

Corticotomy cuts are made in the form of lines and dots

Small circular depressions are placed in facial surface of bone overmaxillary anterior teeth

Bio-absorbable graft is placed (demineralized freeze dried bone)

Tooth movement- should be started after a weak

Tooth movement should be completed within 3-4 months


Wilcodontics

Advantages of graft:

Reduces bone dehiscence/ fenestrationsespecially when lower incisors areadvanced

Good healing of alveolar bone


MODIFIED CORTICOTOMIES:

Micro-osteoperforation: Screws placed in gingiva b/w interproximal alveolar bone and removed

Enough to accelerate RAP

Advantages: Minimally discomfort

Enhanced periodontium


Piezocision:

Minimally invasive flaplessprocedure combining peizoelectricincisions & selective tunneling

Allows for hard and soft tissuegrafting

Indications:

To resolve anterior crowding

Anterior open bite

Advantages: Patient friendly

Less discomfort


Park YG. Patient friendly orthodontics to accelerate tooth movement. Presented at the 23rd Annual conference of Taiwan Association of orthodontics. 2011. Taichung, Taiwan.

Corticision: Aim to cut interradicular bone to 50% to 75% of the root length

Technique: Insert sepcial surgical blade interproximally and parallel to occlusal

plane 2-3 mm apical from the tip of the papilla

Tap blade with a mallet to a depth of approximately 8mm

Change the angle of the blade to approximately 45 degrees apically and tap the blade to incise to a depth of 10mm to 12mm

Apply orthodontic forces immediately

Activation every two weeks

Extra force to induce minor trauma and to extend the effect


Submucosal Injections of PRP

Autologous Platelet Rich Plasma(PRP) can simulate effects of bonesurgery

PRP contain 5% RBC’s, 1% WBC’s,and 94% platelets

Platelets contain growth factors PDGF,TGF and other components that regulateand stimulate wound healing andamplify osteogenesis

SURGERY SIMULATED APPROACH

Submucosal Injections of PRP

Technique:

0.7ml of PRP injected in labial and lingual attached gingiva fromcanine to canine (immediately after bonding)

Acetaminophen given to control post-injection pain

Rate of orthodontic alignment faster than controls

Liou EJ et al. Submucosal injection of platelet rich plasma accelerates orthodontic tooth movement. Am J Orthod Dentofacial Orthop (in press).

SURGERY SIMULATED APPROACH

In general, all these techniques had draw backs and

uncertainties that made them not commonly used clinically.

However, there has been a rapid increase in the interest levels of product companies to enhance orthodontic tooth movement.

These new approaches have the potential to be the next frontier for orthodontics and its resources.

CONCLUSION

THANK YOU

biology of tooth movement ii

Health & Medicine