Implants in orthodontics / /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


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INTRODUCTION
TERMINOLOGY
HISTORICAL PERSPECTIVE
DENTAL IMPLANTS IN ORTHODONTICS
CLASSIFICATION
BENEFITS OF IMPLANTS
IMPLANTS AS ANCHORAGE
DESIGN OF IMPLANTS
PLACEMENT SITES
SURGICAL PROCEDURE
SURGICAL GUIDES
BONE- IMPLANT INTERFACE
IMPLANT MAINTAINENCE
LOADING PROTOCOLS
OTHER APPLICATIONS
MICROSCREW IMPLANT ANCHORAGE SLIDING
MECHANICS
PROBLEMS ENCOUNTERED
SKELETAL ANCHORAGE SYSTEM
CONCLUSION
REFERENCES

Successful orthodontic treatment has always
required intra oral anchorage with a high
resistance to displacement. Extra oral traction
can be an effective reinforcement, but
demands exceptional patient co-operation. The
size, bulk, cost and invasiveness of prosthetic
Osseo integrated implants have limited their
orthodontic application.

TERMINOLOGY
• Anchorage : resistance to unwanted tooth movement.
• Temporary anchorage device: device that is temporarily fixed

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to the bone for the purpose of enhancing orthodontic
anchorage either by supporting the teeth of the reactive unit
altogether, and is subsequently used.
Implant : a titanium device placed in the bone that replaces
the root of a tooth and enables the attachment of a
prosthesis.
Osseo integration : the attachment of bone to the surface of
an implant.
Immediate loading : a technique in which implants are
restored, and thus, loaded at the time of their placement.

500 B C –Etruscan population

600 A D Mayan population

1700’s John Hunter

1809 Maggiolo

Early 1960 LinkowVent -plant implant

Mid 1960’s – Blade
vent implant


Vitreous carbon implants

Flange fixture

Vitallium screw


Implants can used in orthodontics ,
with following references

• Implants as a source of absolute

anchorage
• Implants used for anchorage and as
abutments for restorations
• Implant site preparation improved by
orthodontics
• Implants in osteogenic distraction

Classification of implants can
be based on :
• Position of the implant can be subperiosteal,
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transosseous, or endosseous .
Titanium is the accepted ideal material for
implant fabrication, but other variants include
gold alloys, vitallium, cobalt-chromium, vitreous
carbon, aluminum oxide ceramics, or nickelchromium-vanadium alloys.
The implant surface maybe rough or smooth,
and may have an additional hydroxyapatite or
titanium-spray coating.

Implant materials

• Material must be : nontoxic, biocompatible,

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possess excellent mechanical properties, and
provide resistance to stress, strain, and
corrosion.
3 categories :
Biotolerant (stainless steel, chromium cobalt
alloys)
Bioinert (titanium, carbon)
Bioactive (hydroxyl apatite, ceramic oxidized
aluminum)

Implant sizes

Various sizes of implants:
• Mini implants- 6mm long, 1.2mm in
diameter
• Standard implants- 6-15mm long, 3-5mm
in diameter
• Maximal load is proportional to the boneimplant contact surface.
• Factors determining the contact area are
length, diameter, shape, and surface
design.

Implant shape

• Determines the bone-implant contact area
available for stress transfer and initial
stability.
Commonly used designs are:
• Cylindrical or cylindrical- conical, with a
smooth or threaded surface.
• Degree of surface roughness is related to
the degree of Osseo integration.

The main area of dispute focuses on how
an implant gains its support from the
surrounding bone. A screw thread around
the implant surface aids loading of the
surrounding bone in compression,
whereas a smooth cylindrical design
increases implant support when shear
forces are exerted on the bone. Both
these varieties show a more uniform
stress distribution under loading when
compared to other designs.

HISTORY
• In 1945, Gainsforth and Higley used vitallium screws and
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stainless steel wires in dog mandibles to apply orthodontic
forces.
1964, Branemark et al observed a fixed anchorage of
titanium to bone with no adverse tissue response.
In 1969, Linkow placed blade implants to anchor rubber
bands to retract teeth ,but he never presented long term
results.
In 1969, titanium implants were stable over 5 years and
Osseo integrated in bone under light microscopy view.
In 1984, Roberts et al , corroborated the use of implants in
orthodontic anchorage by using titanium screws in rabbit
femur.
First clinical report in the literature of the use of TADs
appeared in 1983, Creek more and Eklund used a vitallium
bone screw to treat patient with deep impinging overbite.

TEMPORARY ANCHORAGE DEVICES

Biocompatible
Osseo integration

Dental implant
Palatal implant

Biological
Osseo integration
– ankylosed teeth

Mechanical retention

Fixation screws
Mini screw
Fixation wire


Mechanical
- Dilacerated teeth

Osseo-integrated implants and
orthodontics

• In malocclusions requiring a high level of anchorage control,
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Osseo-integrated implants can be used on a temporary
basis to minimize loss of anchorage.
Roberts et al, used conventional, two-stage titanium
implants in the retro molar region, to help reinforce
anchorage whilst successfully closing first molar extraction
sites in the mandible. After completion of the orthodontic
treatment, the implants were removed using a trephine and
histologically analyzed. They found a high level of Osseointegration had been maintained, despite the orthodontic
loading.
In another study, Turley et al. used tantalum markers and
bone labeling dyes in dogs to illustrate the stability of twostage implants in cases of orthodontic or orthopedic traction.
This work also showed that one-stage implants were less
successful in this role.

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Benefits of implants in treatment of
malocclusions
Retracting and realigning anterior teeth with no
posterior support.
Closing edentulous spaces in first molar
extraction sites.
Centre-line correction when missing posterior
teeth.
Re-establishing proper transverse and anteroposterior position of isolated molar abutments.
Intruding/extruding teeth.
Protraction or retraction of one arch.
Stabilization of teeth with reduced bone
support.
Orthopedic traction.

Block and Hoffman addressed the issue of bone height by
developing a disc-like structure called an ‘onplant’ , which is
designed to be placed under local anesthetic. This hydroxyapatitecoated disc is 10 mm in diameter by 3 mm thick, and is placed
subperiosteally on the posterior aspect of the hard palate, using a
‘tunneling’ surgical procedure


Wehrbein and Merz have developed the Straumann Orthosystem
implant (Institute Straumann AG, Walden burg, Switzerland), which can
be up to 6mm in height, based on the potential bone depth available.
The Orthosystem implant is a one-piece device with an 8-week healing
period. It is composed of a screw-type endosseous section of between
4mm and 6mm in length (depending on palatal depth), a cylindrical
transmucosal neck and an abutment, to which a transpalatal arch
attaches.


The increasing desire for early loading of implants used for
orthodontic anchorage led Melsen et al to develop the Aarhus
implant. Due to its small dimensions (6 mm length), this titanium
anchorage screw can be located in multiple sites, including between
the roots of teeth. It is said to allow Osseo-integration to occur even in
the presence of immediate orthodontic loading, providing the
orthodontic forces (25–50 g from Sentalloy springs) pass through the
screw. The strain that develops in the bone surrounding the loaded
screw leads to a local environment in which increased bone formation
results. Due to the size of the screw it can be used in a number of
different locations and can be easily removed when no longer
required.

This is a self tapping , commercially pure titanium miniscrew. The
screw can be immediately loaded with forces in the range of 50 to
300g. available in either 1.5mm or 2.0mm diameter. The 1.5mm
comes in lengths of 6, 8, or 10mm. The 2.0mm comes as 7, 9, or
11mm lengths.
The placement of screw requires sufficient bone depth of at least
2.5mm to protect the anatomic structures.


Kanomi has described a mini-implant, which is 6 mm in length and 1.2
mm in diameter. This was developed from a mini-bone screw used for
fixing bone plates, is screwed into the alveolus under local anesthetic,
to within 3 mm of the apices of the teeth. Subsequent to healing and
Osseo-integration, a titanium bone plate is fixed to the screw, and acts
as a hook for the attachment of an orthodontic ligature wire to aid
intrusion of the respective teeth. Due to potential oral hygiene
problems, the ligature is not attached directly to the implant.


maxilla
BELOW NASAL SPINE

PALATE

INFRAZYGOMATIC
CREST

RETROMOLAR AREA
AND MOLAR AREA

ALVEOLAR PROCESS

Mandible


SYMPHYSIS

Surgical guide for optimal
positioning of mini implant


Pre- surgical evaluation


Acrylisation


Self drilling method

Self tapping method- attached
gingival area


Self tapping method –
movable mucosal area


Bone – implant interaction
• Endosseous implantation in to cortical bone elicits a
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unique sequence of modeling and remodeling events
that are critical to healing, adaptation, and long term
maintenance of the bone implant interface.
Callus formed at the endosteal and periosteal
surfaces is the first vital bone to contact the implant.
Initial healing response is driven by release of local
chemical factors such as PDGF, TGF-ß and PGs.
Remodeling of boneimplant interface is of
importance because it is the mechanism for forming a
vital interface between the implant and host bone.


Peri implant bone response to orthodontic
loading - Oyonarte et al :AJO august 2005.

• Smaller amounts and less variability in crestal bone loss were
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seen in porous surface implants compared with machine
threaded implants in both control and orthodontically loaded
subjects.
Orthodontic loading does not seem to affect the amount of
direct bone-to-implant contact with Osseo integrated implants.
Implant surface design appears to be an important determinant
of peri implant bone remodeling with dental implants used as
orthodontic anchorage units.
Sintered , porous surface implants show more favorable
patterns of bone remodeling under orthodontic loading
compared with machine threaded implants, suggesting that
shorter implant lengths still maintain Osseo integration.

Drill free Vs Drill type implants
Drill free advantages:
• Reduce operative time
• Lower morbidity
• Less invasive
• DF had more bone –to-implant contact
and a larger bone area than D type.
• DF had increased level of bone
remodeling and Osseo integration.

• For easy removal, low torque is needed

which is proportional to the square of screw
radius.
• Removal torque is directly proportional to
screw radius and bone contact area, which
is proportional to screw radius under same
bone contact ratio.
• When screw radius reduces to one-third/
one-fourth, the removal torque is
decreased by one-ninth / one-sixteenth.

As bone density increases, the resistance created by the stress surrounding
the screw becomes important in removal than in insertion of the screw. At
removal, the stress is concentrated in neck, which may lead to fracture.


CLINICAL APPLICATIONS OF
THE MINISCREW IMPLANT


Correction
of cant
occlusal plane

Alignment
of dental
midlines
Extrusion
of impacted
canines
Molar intrusion
Molar distalisation
Molar mesialisation

Symmetrical
incisor
intrusion

Intermaxillary
anchorage

Closure of
extraction
spaces


Closure of extraction spaces

If both intrusive and distalizing forces are needed ,
miniscrew should be positioned above the mucogingival
line.


If the primary movement is to be a distalising
vector, the miniscrew should be placed at
mucogingival line.


•Miniscrew placed high in maxilla must be more
perpendicular to bone to avoid damaging maxillary
sinus
•If screw head is at mucogingival level, it should be
inclined a 30- 450 to interradicular bone


Symmetrical incisor intrusion


Correction of canted occlusal plane

The screws inserted between upper lateral incisor and
canines, upper canines and premolars, or lower lateral
incisor and canines

Miniscrew must be centered between roots of
teeth to be intruded to avoid interference
between teeth and screw


Alignment of dental midlines


Extrusion of impacted canines


Molar intrusion


Molar distalisation


Molar mesialisation


Inter maxillary anchorage


Upper third molar alignment


IMPLANT MAINTENANCE

• After surgery, the surrounding soft tissues
must be maintained to ensure longevity of
implant. Plaque accumulation near the
gingival margin can cause perimucositis.
Prolonged inflammation leads to
breakdown of bone around implants and
peri implantitis. Therefore , patient is
instructed to follow daily plaque control at
home and have periodic professional
care.

SCREW LOADING PROTOCOLS
• Implants fulfill the criteria for primary stability, but also

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withstand the stress and strain applied. There are
substantial differences between orthodontic and occlusal
forces.
Orthodontic loads are continuous, horizontal, and usually
20 to 300g.
Occlusal loads are discontinuous, vertical and are up to
some kilograms.
To discuss the maximal load, evaluating the design of the
fixtures, the biomechanical requirements, the anatomic
limitations and , the degree of Osseo integration is
needed.

HOW LONG SHOULD WE WAIT
BEFORE LOADING?

• If the implants are planned for future prosthetic

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abutments, a standard healing protocol should
be followed. Direct orthodontic forces generate
less stress on implants due to limited force
impose (300gm).
With dense bone and satisfactory stability,
immediate loading might be feasible.
Threaded implants provide superior mechanical
interlock as compared with cylindrical designs.
Thus, waiting time should be longer for non
threaded implants.

Implant vs. Screw Loading Protocols
in Orthodontics

A Systematic Review
Elizabeth Ohashi; Oscar E. Pecho; Milagros Moron; Manuel O. Lagravere
The Angle Orthodontist: Vol. 76, No. 4, pp. 721–727.

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Eleven articles fulfilled the selection criteria
established. Five studies involved the use of
implants while six involved the use of screws for
orthodontic purposes.
Conclusions: Loading protocols for implants
involve a minimum waiting period of 2 months
before applying orthodontic forces while loading
protocols for screws involve immediate loading or a
waiting period of 2 weeks to apply forces. Success
rates for implants were on average higher than for
screws.

• The short waiting period for healing and Osseo
integration after screw insertion is because of
mechanical retention that is initially obtained.
This gives the screws a sufficient primary
stability to resist orthodontic loading forces,
ranging between 30 and 250 g used in
different orthodontic movements.
• This short waiting period is sufficient for
healing but not for Osseo integration, which is
an important factor in maintaining a rigid
anchorage unit.

• Histologically, it has been demonstrated that

the premature load generates the formation
of fibrous tissue between the bone and the
screw. This layer of tissue gives the
mechanical retention for the screw to not
displace in the direction of the applied force.
• In some cases, this layer of tissue can
become granulation tissue because of the
short time given for the formation of a correct
Osseo integration.

• Forces applied to implants or screws,should
be proportional to the amount of Osseo
integration, which at the same time
depends on the surface contact between
material and osseous tissue.
• Factors that are involved : increase in
surface are length, diameter, and shape of
the appliance.
• According to Favero et al, there is an
inverse relationship between length and
diameter where if the length decreases, the
diameter should increase.

• Liou et al demonstrated that the screws

are clinically stable but not absolutely
stationary when forces are loaded on
them.
• The screws mostly move toward the
direction of the applied force, ranging
from −1 to 1.5 mm displacement.
• For this reason, it is recommended that
they should be placed 2 mm away from
any vital anatomical structure (roots,
nerves).

The following conclusions should be
considered with caution because
only a secondary level of evidence
was found.
• Loading protocols for implants involve a
waiting period of a minimum of 2 months
before applying orthodontic forces.
• Loading protocols for screws involve
immediate loading or a waiting period of 2
weeks to apply orthodontic forces.
• The success rates for implants were, on
average, higher than for screws.

Implants used for anchorage
and as abutments for
restorations

• Cases requiring implants for both restorative management
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and orthodontic anchorage require extensive planning
involving the orthodontist, restorative specialist, oral
surgeon, and periodontist.
There are cost and time implications, and the potential
surgical difficulties of access and local anatomy that may
prejudice against the ideal positioning of a conventional
implant should be borne in mind.
The dimensions of the implant should conform closely to
the desired emergence profile of the final restoration
without compromising the inter-dental bone. For optimal
aesthetics of the emergence profile, the implant head
should be 2 mm below the cemento-enamel junction of
the adjacent teeth.

Implant site preparation
improved by orthodontics

• When there has been bone loss associated with
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periodontal disease, which can significantly affect
the aesthetic outcome and prognosis of implant
treatment.
Teeth that are compromised beyond the scope of
periodontal treatment can be used to develop the
alveolar bone in that region, through orthodontic
traction, to allow the subsequent use of implants.
This ‘forced orthodontic eruption’ of such a
hopeless tooth causes an alteration in the soft
tissue architecture of the periodontium as well as
improving the amount and quality of bone
available for implant placement.

Implants in osteogenic
distraction

• Pilot studies on the maxilla and mandible,

undertaken by Ueda et al have illustrated
the use of Osseo-integrated implants to
transfer continuous distraction forces
through the full width of the distraction site.
This has been successfully completed in
mandibular lengthening, maxillary
advancement, and alveolar ridge
augmentation but requires further research
prior to becoming an established technique

Step-by-step procedure
MAXILLARY ARCH:

• Placement of microscrew implant into the alveolar bone
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between II premolar and I molar on both sides.
Bonding of 0.022 PEA and transpalatal bar for
maintaining arch form.
Partial canine retraction; a canine tied back to the
microscrew implant.
En masse retraction of 6 anterior teeth via 0.016×0.022
archwire hooks ; NiTi closing coil spring conncts the
anterior hooks to the microscrew implant and applies
150g of force on each side.
Finishing; occlusal settling with vertical elastics.

Mandibular arch
• Placement of microscrew implant between the first and
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second molars on both sides.
Partial canine retraction; the canine is tied back to the
second premolar.
En masse retraction of 6 anterior teeth via 0.019×0.025
inch archwire.
Application of an intrusive force to upright and intrude
the mandibular molars by ligating an elastic thread from
implant to mandibular archwire.
Finishing


Controlling the mode of anterior tooth
retraction are:
• Occlusogingival position of the implant,
the height of the anterior hooks, and the
amount of torquing curve given on the
arch wire.
• Implant placed low position -4mm gingival
to arch wire
distalizing force in non
extraction cases
• Position at 8-10mm gingival to arch wire
retraction of anteriors in extraction cases

Characteristics of MIA sliding mechanics

• Allows bodily retraction of 6 anteriors,

while utilizing the force near the center of
resistance.
• Induce early changes of profile.
• Uprighting and intrusion of mandibular
molars induce autorotation of mandible.
• Reduces treatment time.

COMMON PROBLEMS ASSOCIATED
WITH MINI IMPLANTS
1. Screw related problems
2. Operator related problems
3. Patient related problems


Screw related problems
1. Screw can fracture if it is too narrow or the
neck area is not strong enough to withstand
the stress of removal. The solution is to
choose a conical screw with a solid neck
and a diameter appropriate to the quality of
bone.
2. Infection can develop around the screw if
the transmucosal portion is not entirely
smooth.

Operator related problems
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Application of excessive pressure during
insertion of a self drilling screw can fracture the
tip of the screw.
Over tightening can cause it to loosen. It is
crucial to stop turning the screw as soon as the
smooth part of the neck has reached
periosteum.
With a bracket like screw head , the ligature
should be placed on top of the screw in the slot
perpendicular to the wire.
It is important not to wiggle the screw driver
when removing it from screw head.

Patient related problems
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The prognosis for primary stability of a mini implant is
poor ,in cases where the cortex is thinner than 0.5mm
and the density of trabecular bone is low.
In patients with thick mucosa, the distance between the
point of force application and the center of resistance of
the screw will be greater than usual, thus generating a
large moment when a force is applied.
Loosening can occur , even after primary stability has
been achieved, if a screw is inserted in an area with
considerable bone remodeling because of either
resorption of a deciduous tooth or post extraction
healing.
Mini implants are contra indicated in patients with
systemic alteration in the bone metabolism due to
disease, medication , or heavy smoking

MINIBONE PLATES: THE SKELETAL
ANCHORAGE SYSTEM
• The SAS comprises of bone plates and fixation
screws. They are made of commercially pure
titanium that is biocompatible and suitable for
Osseo integration.
• The anchor plate consists of 3 components – the
head, the arm and the body.
• The head component is exposed intra orally and
positioned outside of the dentition so that it does
not interfere with tooth movement. The head has
3 continuous hooks for attachment of orthodontic
forces. Two different types of head based on
direction of hooks.
• The arm is transmucosal and in 3 lengths- short
(10.5mm), medium(13.5mm), long(16.5mm).

The body is positioned subperiosteally
and in 3 configurations- T plate, Y- plate
and I plate


• Maxillary sites : zygomatic buttress and
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piriform rim
Mandible: lateral cortex in most locations
except adjacent to mental foramen.
Y plate maxilla at zygomatic buttress to
intrude and distalise upper molars
I plate in piriform opening for intrusion of
upper anteriors or protraction of upper
molars.
T or L plate placed in body of mandible to
intrude , protract or distalise lower molars. At
anterior border of ascending ramus to
extrude impacted molars.

Advantages
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Made of pure titanium , its safe and stable.
Do not disturb any kind of tooth system as placed
outside dentition.
Easy control of occlusal plane.
Patient compliance not needed
Significant advantage it allows the achievement of
predictable three dimensional molar movements.
Timing of orthodontic treatment: orthodontic force is
applied about 3 weeks after implantation procedure,
but before the Osseo integration of the titanium
screws are implants.
Immediately after orthodontic treatment , all anchor
plates are removed.

The concept of temporary anchorage device
is a relatively new application of more
established clinical methodologies. Although
the clinician can look to the literature for
many answers, much is unknown and will
only be answered by well designed
prospective basic science and clinical trials.
The future development of temporary
anchorage devices for orthodontic anchorage
will establish a more complete understanding
of biology and biomechanics associated with
both Osseo integrated and non integrated
devices.

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Contemporary orthodontics. Proffit
Biomechanics in orthodontics. Rvindra nanda.
Rasmussen RA. The Branemark System of Oral Reconstruction: a colour atlas.
Ishiyaku EuroAmerica Inc., Tokyo, 1992.
Gainsforth BL, Higley LB. A study of orthodontic anchorage possibilities in basal
bone. Am J Orthod Oral Surg 1945; 31 : 406–11
Sherman JA. Bone reaction to orthodontic forces on vitreous carbon dental implants.
Am J Orthod 1978; 74 : 79–87.
Kanomi R. Mini-implant for orthodontic anchorage. J Clin Orthod 1997; 31 : 763–767
Liou EJ, Pai BC, Lin JC. Do miniscrews remain stationary under orthodontic forces?.
Am J Orthod Dentofacial Orthop. 2004; 126:42–47.
Costa A, Raffini M, Melsen B. Micro-screws as orthodontic anchorage. Int J Adult
Orthod Orthognath Surg. 1998; 13:201–209.
MOREa et al. Surgical guide for optimal positioning of mini-implants. CO
2005;39:317-321.
Cousley and parberry. Combined cephalometric and stent planning for palatal
implants.JO 2005;32: 20-25.
Shapiro and kokich. Uses of implants in orthodontics. DCNA 1988;32: 539-549.
Huang et al. dental implants in orthodontics. AJO 2005; 1127:713-722.

•Hyo-Sang park et al. Microscrew implant anchorage sliding mechanics. WJO
2005; 6: 265-274.
•Hee- moon kyung. Development of orthodontic micro implant for intra oral
anchorage. JCO 2003; 37:321-328.
•Trisi and Rebaudi. Progressive bone adaptation of titanium implants during and
after orthodontic load in humans.int. j of perio. Res.2002;22:31-43.
•Arbuckle et al Osseo integrated implants and orthodontics. Oro max. clin
NA.1991;3:903-911.
•Carano etal. Clinical applications of the miniscrew anchorage system. JCO
2005;36: 9-23.


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