Clinical application of mas

Clinical Applications of theClinical Applications of the
Miniscrew Anchorage SystemMiniscrew Anchorage System
ALDO CARANO, DO, MS STEFANO VELO, MDALDO CARANO, DO, MS STEFANO VELO, MD
PAOLA LEONE, DO, MS GIUSEPPE SICILIANI, MD,PAOLA LEONE, DO, MS GIUSEPPE SICILIANI, MD,
DMDDMD
JCO 2005 VOL XXXIX NO 1JCO 2005 VOL XXXIX NO 1
www.indiandentalacademy.comwww.indiandentalacademy.com

 InIn 1983,1983, Creekmore and EklundCreekmore and Eklund were the firstwere the first
orthodontists to suggest that a small metal screw couldorthodontists to suggest that a small metal screw could
withstand a constant force of sufficient magnitude andwithstand a constant force of sufficient magnitude and
duration to reposition an entire anterior maxillaryduration to reposition an entire anterior maxillary
dentition without becoming loose, painful, infected, ordentition without becoming loose, painful, infected, or
pathologic.pathologic.
 Toward the end of the 1980s, a number of cliniciansToward the end of the 1980s, a number of clinicians
focused on the use of standard dental implants asfocused on the use of standard dental implants as
temporary anchorage for orthodontic tooth movementtemporary anchorage for orthodontic tooth movement
and then as permanent abutments for toothand then as permanent abutments for tooth
replacement.replacement.

The major advantage of these implantsThe major advantage of these implants
 move multiple teeth without loss of anchorage.move multiple teeth without loss of anchorage.
 Placed in areas where natural anchorage orPlaced in areas where natural anchorage or
conventional orthodontic appliances are impractical,conventional orthodontic appliances are impractical,
( including the edentulous spaces in the alveolus of( including the edentulous spaces in the alveolus of
either arch, the palate, the zygomatic process, theeither arch, the palate, the zygomatic process, the
retromolar regions, and the ramus. )retromolar regions, and the ramus. )

Disadvantages of dental implantsDisadvantages of dental implants
 Need for an invasive surgical procedure,Need for an invasive surgical procedure,
 The limitations on placement sites imposed by theThe limitations on placement sites imposed by the
implants' 10mm length,implants' 10mm length,
 The time required for osseointegration prior to forceThe time required for osseointegration prior to force
application, andapplication, and
 Cost .Cost .
 In addition, they are not recommended for femaleIn addition, they are not recommended for female
patients younger than 16 or males younger than 18.patients younger than 16 or males younger than 18.

 More recently, new onplants, miniplates, and palatalMore recently, new onplants, miniplates, and palatal
implants have been developed specifically for use inimplants have been developed specifically for use in
orthodontics.orthodontics.
 The miniplatesThe miniplates :- anchorage for molar intrusion;:- anchorage for molar intrusion;
 palatal implantspalatal implants :- space closure, distalization of:- space closure, distalization of
maxillary molars.maxillary molars.
 Repeating the experience ofRepeating the experience of CreekmoreCreekmore, they have, they have
found that small screws, like those used for rigid fixationfound that small screws, like those used for rigid fixation
in maxillofacial surgery, work well for orthodonticin maxillofacial surgery, work well for orthodontic
anchorage.anchorage.
 These new devices still have many of the sameThese new devices still have many of the same
limitations as standard dental implants, however, mostlimitations as standard dental implants, however, most
orthodontists have now turned to mini screws.orthodontists have now turned to mini screws.

 Reduced size.Reduced size.
 The material generally used for miniscrews is medicalThe material generally used for miniscrews is medical
grade 4 or 5 titanium, although stainless steel has beengrade 4 or 5 titanium, although stainless steel has been
proposed as an alternative.proposed as an alternative.
 Recent histological studies in animals have shown thatRecent histological studies in animals have shown that
the osseointegration of titanium miniscrews is less thanthe osseointegration of titanium miniscrews is less than
half that of conventional dental implants.half that of conventional dental implants.
 No significant difference in the bone surrounding theNo significant difference in the bone surrounding the
miniscrew sites whether the miniscrews were loaded orminiscrew sites whether the miniscrews were loaded or
unloaded with force.unloaded with force.
 The presence of more compact bone in the mandibleThe presence of more compact bone in the mandible
may account for some differences in miniscrewmay account for some differences in miniscrew
performance found between the maxillary andperformance found between the maxillary and
mandibular arches .mandibular arches .

 Incomplete osseointegrationIncomplete osseointegration represents a distinctrepresents a distinct
advantage in orthodontic applications, allowing foradvantage in orthodontic applications, allowing for
effective anchorage with easy insertion and removal.effective anchorage with easy insertion and removal.
 The mini screw material and the specific design of theThe mini screw material and the specific design of the
self-tapping portion are still important, in determiningself-tapping portion are still important, in determining
resistance to breakage.resistance to breakage.
 The rotational forces associated with placement andThe rotational forces associated with placement and
removal can cause mini screw failure, especially if theremoval can cause mini screw failure, especially if the
bone consistency is high or a partial integration hasbone consistency is high or a partial integration has
occurred.occurred.
 Differences among various mini screw head designsDifferences among various mini screw head designs
have also been noted with regard to soft tissue healing.have also been noted with regard to soft tissue healing.
 This article illustrates the clinical applications of a newThis article illustrates the clinical applications of a new
titanium mini screw designed for orthodontic anchoragetitanium mini screw designed for orthodontic anchorage..

 The conical screws used inThe conical screws used in
the Miniscrew Anchoragethe Miniscrew Anchorage
System (MAS), made ofSystem (MAS), made of
medical grade 5 titanium,medical grade 5 titanium,
are available in three sizes.are available in three sizes.
 Type A has a diameter ofType A has a diameter of
1.3mm at the top of the neck1.3mm at the top of the neck
and 1.1mm at the tip.and 1.1mm at the tip.
 Type B is 1.5mm in diameterType B is 1.5mm in diameter
at the neck and 1.3mm atat the neck and 1.3mm at
the tip. Both types arethe tip. Both types are
11mm long.11mm long.
 Type C, which is 9mm long,Type C, which is 9mm long,
has a diameter of 1.5mm athas a diameter of 1.5mm at
the neck and 1.3mm at thethe neck and 1.3mm at the
tip.tip.
Miniscrew DesignMiniscrew Design

 The screw head consists of two fused spheres (theThe screw head consists of two fused spheres (the
upper 2.2mm in diameter, the lower 2mm), with anupper 2.2mm in diameter, the lower 2mm), with an
internal hexagon for insertion of the placementinternal hexagon for insertion of the placement
screwdriver.screwdriver.
 A 0.6 mm horizontal slot at the junction of the twoA 0.6 mm horizontal slot at the junction of the two
spheres allows for The attachment of elastics, chains,spheres allows for The attachment of elastics, chains,
coil springs, ligature wires, or auxiliary hooks.coil springs, ligature wires, or auxiliary hooks.

 Two methods were chosen to test these screwsTwo methods were chosen to test these screws
mechanically, representing two potential modes ofmechanically, representing two potential modes of
failure during insertion and removal:failure during insertion and removal:
Torsional strength and Bending strengthTorsional strength and Bending strength..
 The tests were conducted in the Department ofThe tests were conducted in the Department of
Mechanical Engineering at the University of Genoa,Mechanical Engineering at the University of Genoa,
Italy, by seating the screws in a tapped brass block at aItaly, by seating the screws in a tapped brass block at a
thread depth of 6mm.thread depth of 6mm.
 ForFor torsion-to-failure testingtorsion-to-failure testing,, a dial torque wrencha dial torque wrench
with a recording device was turned in a clockwisewith a recording device was turned in a clockwise
direction, perpendicular to the long axis of the screw.direction, perpendicular to the long axis of the screw.
MECHANICAL TESTING

 ForFor bending-to-failure testingbending-to-failure testing,, a dial bending arma dial bending arm with awith a
recording device was used to deform the screw along itsrecording device was used to deform the screw along its
long axis in a clockwise direction. Six screws were used forlong axis in a clockwise direction. Six screws were used for
each testeach test
 The mean resistance to breakage in torsion was 48.7NcmThe mean resistance to breakage in torsion was 48.7Ncm
for the 1.5mm-diameter miniscrew and 37.4Ncm for thefor the 1.5mm-diameter miniscrew and 37.4Ncm for the
1.3mm-diameter miniscrew.1.3mm-diameter miniscrew.
 The mean resistance to breakage in flexion was 120.4NThe mean resistance to breakage in flexion was 120.4N
for the 1.5mm-diameter miniscrew and 91.7N for thefor the 1.5mm-diameter miniscrew and 91.7N for the
1.3mm diameter miniscrew.1.3mm diameter miniscrew.
 These results suggest that the MAS screws can resist aThese results suggest that the MAS screws can resist a
force much greater than that of any orthodontic application.force much greater than that of any orthodontic application.

 It is possible, however, to apply a torsional force ofIt is possible, however, to apply a torsional force of
more than 40Ncm during insertion or removal and thusmore than 40Ncm during insertion or removal and thus
to break the screw.to break the screw.
 To limit this torsional force, the clinician should use aTo limit this torsional force, the clinician should use a
small screwdriver and hold it by the fingertips.small screwdriver and hold it by the fingertips.
 If the self-tapping screw encounters extreme resistanceIf the self-tapping screw encounters extreme resistance
during insertion, additional pilot drilling may beduring insertion, additional pilot drilling may be
required.required.
 At the time of removal, if the screw seems to be OsseoAt the time of removal, if the screw seems to be Osseo
integrated, a minor surgical procedure may be neededintegrated, a minor surgical procedure may be needed
to remove it completely.to remove it completely.

Placement SitesPlacement Sites
 Miniscrews are used in place of traditional appliancesMiniscrews are used in place of traditional appliances
such as headgear and lingual arches in cases wheresuch as headgear and lingual arches in cases where
absolute anchorage is necessary.absolute anchorage is necessary.
 From a biomechanical standpoint, miniscrews allowFrom a biomechanical standpoint, miniscrews allow
more bodily tooth movement during space closure bymore bodily tooth movement during space closure by
placing the force vectors closer to the center ofplacing the force vectors closer to the center of
resistance of the teeth.resistance of the teeth.

The sites most often utilized for MAS insertion in theThe sites most often utilized for MAS insertion in the
maxillamaxilla include:include:
 Interradicular spaces, both buccal and lingualInterradicular spaces, both buccal and lingual
 Extraction spacesExtraction spaces
 Inferior surface of the anterior nasal spineInferior surface of the anterior nasal spine

In theIn the mandiblemandible, the most common mini-screw, the most common mini-screw
placement sites are:placement sites are:
 Interradicular spaces, both buccal and lingualInterradicular spaces, both buccal and lingual
 Lateral to the mentalis symphisisLateral to the mentalis symphisis
 Extraction spacesExtraction spaces
 The most useful locations are the interradicular spaces,The most useful locations are the interradicular spaces,
either buccal or lingual, between the second premolarseither buccal or lingual, between the second premolars
and first molars in both arches, or the buccal spaceand first molars in both arches, or the buccal space
between the upper lateral incisor and canine.between the upper lateral incisor and canine.

 A surgical guide can be made from a rectangular wireA surgical guide can be made from a rectangular wire
segment to help identify the mini-screw location on thesegment to help identify the mini-screw location on the
intraoral x-ray.intraoral x-ray.
 The self-tapping screw often requires no preparation ofThe self-tapping screw often requires no preparation of
the medullary bone.the medullary bone.
 If the bone is too dense, however, a bur (0.9mm forIf the bone is too dense, however, a bur (0.9mm for
Type A, I.I mm for Type B) should be used to drill a pilotType A, I.I mm for Type B) should be used to drill a pilot
hole through the gingival and cortical bone under localhole through the gingival and cortical bone under local
anesthesia.anesthesia.
SURGICAL PROCEDURE

 The author recommend placing a stop on the bur to limitThe author recommend placing a stop on the bur to limit
the depth of insertion to 2-3mm, but it is critical that thethe depth of insertion to 2-3mm, but it is critical that the
depth be 2 mm shorter than the miniscrew. The axialdepth be 2 mm shorter than the miniscrew. The axial
inclination of the bur must be the same as the desiredinclination of the bur must be the same as the desired
incli-nation of the miniscrew.incli-nation of the miniscrew.
 A metallic marker, which can be attached to a vacuum-A metallic marker, which can be attached to a vacuum-
formed retainer or directly to the brackets, can be usedformed retainer or directly to the brackets, can be used
to show the position of the miniscrew relative to the rootsto show the position of the miniscrew relative to the roots
on the pre and post-placement panoramic or periapicalon the pre and post-placement panoramic or periapical
radiographsradiographs

 Vessels and nerves are easily avoided by properVessels and nerves are easily avoided by proper
interpretation of the x-ray images.interpretation of the x-ray images.
 The roots are more difficult to identify, but damage canThe roots are more difficult to identify, but damage can
be eliminated by limiting any pilot drilling to the corticalbe eliminated by limiting any pilot drilling to the cortical
plate of the alveolar bone (2-3mm).plate of the alveolar bone (2-3mm).
 If a self-tapping screw encounters a root duringIf a self-tapping screw encounters a root during
insertion, it will stop, and can then be redirected by theinsertion, it will stop, and can then be redirected by the
clinician.clinician.

 A manual screwdriverA manual screwdriver is used to insert the miniscrew,is used to insert the miniscrew,
preferably between the free and attached gingiva.preferably between the free and attached gingiva.
 When properly placed, the screw head will protrudeWhen properly placed, the screw head will protrude
through the soft tissue.through the soft tissue.
 Once the initial stability of the miniscrew has beenOnce the initial stability of the miniscrew has been
confirmed, an orthodontic force ofconfirmed, an orthodontic force of 50-250g50-250g can becan be
applied immediately.applied immediately.
 The head of the mini-screw has been designed toThe head of the mini-screw has been designed to
prevent compression of the mucosa, but if this occursprevent compression of the mucosa, but if this occurs
after placement a chain or nickel titanium coil spring,after placement a chain or nickel titanium coil spring,
or Monkey Hooks can be used instead.or Monkey Hooks can be used instead.

 Post-operative antibiotics or analgesics are usually notPost-operative antibiotics or analgesics are usually not
needed.needed.
 Once the orthodontic anchorage is no longer required,Once the orthodontic anchorage is no longer required,
the screw can be easily removed with the manualthe screw can be easily removed with the manual
screwdriver, usually without local anesthesia.screwdriver, usually without local anesthesia.
 The mucosa generally heals within a few days, andThe mucosa generally heals within a few days, and
new bone fills in the placement site.new bone fills in the placement site.

Closure of Extraction SpacesClosure of Extraction Spaces
 Loss of posterior anchorage during extraction spaceLoss of posterior anchorage during extraction space
closure can exacerbate the curve of Spee and deepenclosure can exacerbate the curve of Spee and deepen
the bite.the bite.
 Miniscrews provide reliable skeletal anchorage forMiniscrews provide reliable skeletal anchorage for
anterior retraction in either arch, whether a single toothanterior retraction in either arch, whether a single tooth
at a time or en masse.at a time or en masse.
 Maxillary miniscrews are usually placedMaxillary miniscrews are usually placed between thebetween the
roots of the first and second premolarsroots of the first and second premolars, where the large, where the large
inter radicular space typically allows easy insertioninter radicular space typically allows easy insertion
without root interference.without root interference.
APPLICATIONS OF MAS

 The screw heads can be situated at or above theThe screw heads can be situated at or above the
mucogingival line, depending on the desired line ofmucogingival line, depending on the desired line of
action.action.
 If both intrusive and distalizing forces are needed, theIf both intrusive and distalizing forces are needed, the
miniscrew should be positioned above the mucogingivalminiscrew should be positioned above the mucogingival
line).line).

 If the primary movement is to be a distalizing vector,If the primary movement is to be a distalizing vector,
however, the miniscrew should be placed at thehowever, the miniscrew should be placed at the
mucogingival line.mucogingival line.

The higher the screw is placed in the maxilla, the more
perpendicular to the bone it must be to avoid damage to
to the maxillary sinus
If screw head is at mucogingival level, it should be
inclined at 30-45° to inter radicular bone.

 If the alveolar process is prominent, an auxiliary suchIf the alveolar process is prominent, an auxiliary such
as a Monkey Hook can be used to keep the chain oras a Monkey Hook can be used to keep the chain or
coil spring away from the soft tissue, thus avoidingcoil spring away from the soft tissue, thus avoiding
discomfort and gingival irritation.discomfort and gingival irritation.
 In the mandibular arch, miniscrews can be useful inIn the mandibular arch, miniscrews can be useful in
patients where maximum anchorage is needed, suchpatients where maximum anchorage is needed, such
as bialveolar protrusion and Class Ill cases.as bialveolar protrusion and Class Ill cases.
 Placing miniscrews between the roots of the lower firstPlacing miniscrews between the roots of the lower first
and second premolars is not recommended however,and second premolars is not recommended however,
because of the proximity of the mentalis foramen.because of the proximity of the mentalis foramen.

Symmetrical Incisor IntrusionSymmetrical Incisor Intrusion
 Many patients present with moderate-to-severe deepMany patients present with moderate-to-severe deep
bites requiring pure intrusion of the anterior teeth to levelbites requiring pure intrusion of the anterior teeth to level
the occlusal plane.the occlusal plane.
 Unless the deep bite is so extreme that absoluteUnless the deep bite is so extreme that absolute
anchorage is needed, it may be inadvisable to placeanchorage is needed, it may be inadvisable to place
miniscrews simultaneously in both arches in youngminiscrews simultaneously in both arches in young
patients.patients.
 In these cases, miniscrews can be used to reinforceIn these cases, miniscrews can be used to reinforce
conventional orthodontic mechanics.conventional orthodontic mechanics.

To provide anchorage during incisor intrusion, miniscrews can beTo provide anchorage during incisor intrusion, miniscrews can be
placed between the upper lateral incisors and canines.placed between the upper lateral incisors and canines.
The insertion should not be performed until after leveling and
alignment, however, so that the maximum amount of interradicular
space will be available.
To avoid tipping the upper incisors buccally during intrusion, the ends
of the arch-wire should be cinched back.

Correction of a Canted Occlusal PlaneCorrection of a Canted Occlusal Plane
 A canted occlusal plane is often considered impossibleA canted occlusal plane is often considered impossible
to level with traditional orthodontic treatment.to level with traditional orthodontic treatment.
 Miniscrews, on the other hand, provide skeletalMiniscrews, on the other hand, provide skeletal
anchorage for intrusion of the appropriate teeth on theanchorage for intrusion of the appropriate teeth on the
canted side.canted side.
A. Patient with canted occlusal
plane. B. Miniscrew centered
between roots of upper lateral
incisor and first premolar on
canted side (ankylosed
impacted canine was
extracted). C. Intrusion of upper
lateral incisor and first premolar.
D. After leveling of occlusal
plane.

 The screws can be insertedThe screws can be inserted
between the upper lateral incisorsbetween the upper lateral incisors
and canines, the upper caninesand canines, the upper canines
and premolars, or the lowerand premolars, or the lower
lateral incisors and canines.lateral incisors and canines.
 To avoid interference with theTo avoid interference with the
teeth to be intruded, it isteeth to be intruded, it is
important to center theimportant to center the
miniscrews between their roots.miniscrews between their roots.

Alignment of Dental MidlinesAlignment of Dental Midlines
 When an entire arch needs to be moved laterally toWhen an entire arch needs to be moved laterally to
correct the posterior malocclusion, the dental midlinescorrect the posterior malocclusion, the dental midlines
are usually aligned with intermaxillary elastics, requiringare usually aligned with intermaxillary elastics, requiring
considerable patient compliance.considerable patient compliance.
 Vertical forces may be contraindicated in some cases,Vertical forces may be contraindicated in some cases,
or the intermaxillary elastics may decompensate theor the intermaxillary elastics may decompensate the
arches from a frontal prospective, causing the bite toarches from a frontal prospective, causing the bite to
open.open.

 In these more complex cases ofIn these more complex cases of
midline deviation, miniscrews may bemidline deviation, miniscrews may be
a useful alternative.a useful alternative.
 A screw can be placed eitherA screw can be placed either
lingually or buccally so that the headlingually or buccally so that the head
stands out at the crown margins.stands out at the crown margins.
Thus, the line of force is directedThus, the line of force is directed
more occlusally, with an enhancedmore occlusally, with an enhanced
horizontal vector.horizontal vector.

Molar IntrusionMolar Intrusion
 Opinions have differed regarding the efficacy ofOpinions have differed regarding the efficacy of
orthodontic intrusion of posterior teeth.orthodontic intrusion of posterior teeth.
 Miniscrews can be a reliable source of anchorage andMiniscrews can be a reliable source of anchorage and
placed them precisely in the narrow space between theplaced them precisely in the narrow space between the
roots of the first and second molars without interferingroots of the first and second molars without interfering
with the roots.with the roots.

 In some cases, more than one screw might even beIn some cases, more than one screw might even be
needed to withstand a relatively high intrusion force.needed to withstand a relatively high intrusion force.
 Use of miniscrews to situations where simple intrusion ofUse of miniscrews to situations where simple intrusion of
one or two molars is needed and where placement willone or two molars is needed and where placement will
be unproblematic.be unproblematic.
 In open-bite cases requiring bilateral intrusion of theIn open-bite cases requiring bilateral intrusion of the
posterior segments, mini-screws are not an idealposterior segments, mini-screws are not an ideal
solution.solution.

Molar DistalizationMolar Distalization
 Fixed and removable maxillary molar distalization devicesFixed and removable maxillary molar distalization devices
for the correction of Class II malocclusions range from fixedfor the correction of Class II malocclusions range from fixed
devices that are activated by the orthodontist to open-coildevices that are activated by the orthodontist to open-coil
springs, but most utilize some form of palatal coverage tosprings, but most utilize some form of palatal coverage to
provide anchorage and prevent incisor flaring.provide anchorage and prevent incisor flaring.
 Nevertheless, studies of molar distalization have shown aNevertheless, studies of molar distalization have shown a
considerable amount of anterior anchorage loss.considerable amount of anterior anchorage loss.
 The ideal site for skeletal anchorage would be the palate,The ideal site for skeletal anchorage would be the palate,
but this requires a surgical procedure to place the implantbut this requires a surgical procedure to place the implant
and another to remove it.and another to remove it.
 Screws less than 2mm in diameter are unstable when usedScrews less than 2mm in diameter are unstable when used
for palatal anchorage and routinely fail.for palatal anchorage and routinely fail.

The MAS + DistalThe MAS + Distal JetJet ..
 After the Distal Jet appliance has been placed andAfter the Distal Jet appliance has been placed and
activated, palatal miniscrews are inserted between theactivated, palatal miniscrews are inserted between the
roots of the first and second premolars, mesial to theroots of the first and second premolars, mesial to the
activation locks attached to the anterior restsactivation locks attached to the anterior rests
 The miniscrews block mesial movement of the applianceThe miniscrews block mesial movement of the appliance
during distalization, thus preventing loss of anteriorduring distalization, thus preventing loss of anterior
 Further compression of the Distal Jet's coil springs willFurther compression of the Distal Jet's coil springs will
move the locks distally, away from the miniscrews.move the locks distally, away from the miniscrews.

 During this phase, anchorage loss can be prevented by bondingDuring this phase, anchorage loss can be prevented by bonding
lightcured composite between the screw heads and the lockslightcured composite between the screw heads and the locks
 After molar distalization, the Distal Jet is converted to a passiveAfter molar distalization, the Distal Jet is converted to a passive
retainer, and brackets are bonded to the teeth for completion of theretainer, and brackets are bonded to the teeth for completion of the
Class II correctionClass II correction

Another option is to remove the miniscrew after molar
distalization and replace it just mesial to the distalized
molar, where it will stabilize the molar while the remaining
teeth are moved posteriorly
The MAS + Distal Jet should not be used in the mixed
dentition, because the palatal screw may interfere with
developing permanent teeth

Molar MesializationMolar Mesialization
 Molars are often moved mesially in orthodontic treatmentMolars are often moved mesially in orthodontic treatment
to close extraction spaces or edentulous spaces.to close extraction spaces or edentulous spaces.
 Molar mesialization is not a simple movement and canMolar mesialization is not a simple movement and can
lead to problems such as loss of anterior anchorage andlead to problems such as loss of anterior anchorage and
molar tipping. Furthermore, if there is a knife-edgemolar tipping. Furthermore, if there is a knife-edge
alveolar ridge in the space to be closed, alveolar bonealveolar ridge in the space to be closed, alveolar bone
may be lost.may be lost.
 A miniscrew placed mesial to the space, at a height thatA miniscrew placed mesial to the space, at a height that
will produce a force vector approximating the center ofwill produce a force vector approximating the center of
resistance of the molar, can be a valuable source ofresistance of the molar, can be a valuable source of

 If the screw is inserted after the initial leveling andIf the screw is inserted after the initial leveling and
alignment have been completed, a full-size archwire canalignment have been completed, a full-size archwire can
be used to prevent mesial crown tipping of the molarbe used to prevent mesial crown tipping of the molar
during space closure.during space closure.
 Because mesial movement is usually slow, especially inBecause mesial movement is usually slow, especially in
the mandibular arch, no more than 2-3mm of molarthe mandibular arch, no more than 2-3mm of molar
mesialization should be attempted.mesialization should be attempted.

Intermaxillary AnchorageIntermaxillary Anchorage
 Miniscrews are a convenient source of anchorage inMiniscrews are a convenient source of anchorage in
both extraction and nonextraction therapy whenboth extraction and nonextraction therapy when
intermaxillary forces are applied with Class II elastics orintermaxillary forces are applied with Class II elastics or
anterior repositioning appliances.anterior repositioning appliances.
 Many undesirable side effects can be produced by suchMany undesirable side effects can be produced by such
mechanics, including bite opening and excessivemechanics, including bite opening and excessive
proclination and protrusion of the lower incisors.proclination and protrusion of the lower incisors.
 One possible solution is to place a miniscrew betweenOne possible solution is to place a miniscrew between
the roots of the lower first and second molars or thethe roots of the lower first and second molars or the
second pre-molar and first molar.second pre-molar and first molar.
 TheThe location between the second premolar and firstlocation between the second premolar and first
molar (as close as possible to the first molar)molar (as close as possible to the first molar) is generallyis generally
preferable, because the screw must be insertedpreferable, because the screw must be inserted
perpendicular to the alveolar process, which can beperpendicular to the alveolar process, which can be
difficult in more posterior regions where access isdifficult in more posterior regions where access is
limited.limited.

 In addition, the interradicular space between the secondIn addition, the interradicular space between the second
premolar and first molar is wider than the space betweenpremolar and first molar is wider than the space between
the first and second molars.the first and second molars.
 Placement of the miniscrew mesial to the first molar mayPlacement of the miniscrew mesial to the first molar may
also prevent mesial movement of the entire lower arch,also prevent mesial movement of the entire lower arch,
although care must be taken to avoid contact with thealthough care must be taken to avoid contact with the
molar roots.molar roots.
 InIn Class III treatmentClass III treatment, when the maxillary arch needs to, when the maxillary arch needs to
be advanced, miniscrews can be placedbe advanced, miniscrews can be placed between thebetween the
roots of the lower canines and first premolarsroots of the lower canines and first premolars for elasticfor elastic
attachment .attachment .
 If the mandibular arch needs to be repositioned distally,If the mandibular arch needs to be repositioned distally,
the miniscrews can be placed between the roots of thethe miniscrews can be placed between the roots of the
upper first and second molars or second premolars andupper first and second molars or second premolars and
first molars.first molars.

Upper Third Molar AlignmentUpper Third Molar Alignment
 Miniscrews can also be useful in cases with multiple missingMiniscrews can also be useful in cases with multiple missing
teeth where conventional orthodontic mechanics are difficultteeth where conventional orthodontic mechanics are difficult
to apply.to apply.
 An upper third molar can be uprighted with a fixed sectionalAn upper third molar can be uprighted with a fixed sectional
wire, utilizing a palatal miniscrew for skeletal anchorage towire, utilizing a palatal miniscrew for skeletal anchorage to
limit unwanted extrusion of the molar.limit unwanted extrusion of the molar.

DiscussionDiscussion
Placement of a mini screw depends on orthodontic considerations
such as
• force vectors
• the types of anchorage
• tooth movement required.
Differences in size, shape (conical or cylindrical), head design,
pilot drilling, and physical properties can influence the likelihood of
successful treatment or minimize potential complications such as
breakage at the neck during the application of orthodontic forces is
still unknown.
Histological studies have confirmed that titanium screws are
biocompatible and are easily removed because of their incomplete
Osseo integration.

 Reducing diameters of selftapping screws :- reduction in theirReducing diameters of selftapping screws :- reduction in their
mechanical resistance,mechanical resistance,
 Testing to breakage in torsion and flexion to be a fundamental stepTesting to breakage in torsion and flexion to be a fundamental step
before the clinical application of any new mini screws.before the clinical application of any new mini screws.
 In preliminary testing of the MAS screws, they were able to resistIn preliminary testing of the MAS screws, they were able to resist
forces much greater than any applied in orthodontic treatment, butforces much greater than any applied in orthodontic treatment, but
that caution was required during insertion and removal to avoidthat caution was required during insertion and removal to avoid
applying torsional forces that might break the screws.applying torsional forces that might break the screws.
 Sometimes the screw needs to be relocated to a better positionSometimes the screw needs to be relocated to a better position
during treatment, which may become complicated if the patient hasduring treatment, which may become complicated if the patient has
to be referred to a specialist.to be referred to a specialist.

Advantages of miniscrewsAdvantages of miniscrews over other forms ofover other forms of
anchorage include:anchorage include:
 Optimal use of traction forces, regardless of theOptimal use of traction forces, regardless of the
number or positions of the teethnumber or positions of the teeth
 Applicability at any stage of development, includingApplicability at any stage of development, including
interceptive therapyinterceptive therapy
 Shorter treatment time, with no need to prepare dentalShorter treatment time, with no need to prepare dental
anchorageanchorage
 Independence of patient cooperationIndependence of patient cooperation
 Patient comfortPatient comfort
 Low costLow cost

ComplicationsComplications common to all implant procedures,common to all implant procedures,
including:including:
•• Damage to anatomic structures such as nerves,Damage to anatomic structures such as nerves,
vessels, and rootsvessels, and roots
 Loss of a screw during placement or loadingLoss of a screw during placement or loading
Breakage of a screw within the bone during insertion orBreakage of a screw within the bone during insertion or
removalremoval
 Inflammation around implant sitesInflammation around implant sites

With the MAS,these are minimisedWith the MAS,these are minimised
 Breakage may be more likely with screws of smallerBreakage may be more likely with screws of smaller
diameter.diameter.
 Furthermore, the MAS offers several advantagesFurthermore, the MAS offers several advantages
compared to more invasive Osseo integrated systems:compared to more invasive Osseo integrated systems:
 Increased selection of insertion sitesIncreased selection of insertion sites
 Ease of insertion and removalEase of insertion and removal
 Ability to withstand immediate loadingAbility to withstand immediate loading
 Applicability in growing patientsApplicability in growing patients
 Low costLow cost

REFERENCESREFERENCES
 1. Crcckmore, T. and Eklund, M.K.; The possibility of skeletal anchorage, J. Clin.1. Crcckmore, T. and Eklund, M.K.; The possibility of skeletal anchorage, J. Clin.
Orthod. 17:266-269, 1983.Orthod. 17:266-269, 1983.
 2. Roberts, W.E.; Marshall, J.K.; and Mozsary, P.G.: Rigid endosseous implant2. Roberts, W.E.; Marshall, J.K.; and Mozsary, P.G.: Rigid endosseous implant
utilized as anchorage to protract molars and close an atrophic extraction site, Angleutilized as anchorage to protract molars and close an atrophic extraction site, Angle
Orthod. 60:135-152, 1990.Orthod. 60:135-152, 1990.
 3. Celenza, F. and Hochman, M.N.: Absolute anchorage in ortho-dontics: Direct and3. Celenza, F. and Hochman, M.N.: Absolute anchorage in ortho-dontics: Direct and
indirect implant-assisted modalities, J. Clin. Orthod. 34:397-402, 2000.indirect implant-assisted modalities, J. Clin. Orthod. 34:397-402, 2000.
 4. Gray, J.B. and Smith, R.: Transitional implants for orthodontic anchorage, J. Clin.4. Gray, J.B. and Smith, R.: Transitional implants for orthodontic anchorage, J. Clin.
Orthod. 34:659-666, 2000.Orthod. 34:659-666, 2000.
 5. Wehrbein, H. and Merz, B.R.: Aspects of the use of endosseous palatal implants in5. Wehrbein, H. and Merz, B.R.: Aspects of the use of endosseous palatal implants in
orthodontic therapy, J. Esth. Dent. 10:315-324, 1998.orthodontic therapy, J. Esth. Dent. 10:315-324, 1998.
 6. Block, M.S. and Huffman, D.R.: A new device for absolute anchorage for6. Block, M.S. and Huffman, D.R.: A new device for absolute anchorage for
orthodontics, Am. J. Orthod. 107:251 -258, 1995.orthodontics, Am. J. Orthod. 107:251 -258, 1995.
 7. Umemori, M.; Sugawara, J.; Mitani, H.; Nagasaka, H.; and Kawamura, H.: Skeletal7. Umemori, M.; Sugawara, J.; Mitani, H.; Nagasaka, H.; and Kawamura, H.: Skeletal
anchorage system for open-bite cor-rection, Am. J. Orthod. 115:166-174, 1999.anchorage system for open-bite cor-rection, Am. J. Orthod. 115:166-174, 1999.
 8. Mura, P.; Maino, B.; and Paoletto, E.: Midplant: L'ancoraggio assoluto in8. Mura, P.; Maino, B.; and Paoletto, E.: Midplant: L'ancoraggio assoluto in
ortodonzia, Ortod. Tecnica 3:7-11, 2000.ortodonzia, Ortod. Tecnica 3:7-11, 2000.
 9. Daimaruya, T.; Nagasaka, H.; Umemori, M.; Sugawara, J.; Mitani, H.: The9. Daimaruya, T.; Nagasaka, H.; Umemori, M.; Sugawara, J.; Mitani, H.: The
influences of molar intrusion on the inferior alveolar neurovascular bundle and rootinfluences of molar intrusion on the inferior alveolar neurovascular bundle and root
using the skeletal anchorage system in dogs, Angle Orthod. 71:60-70, 2001.using the skeletal anchorage system in dogs, Angle Orthod. 71:60-70, 2001.
 10. Sugawara, .1.; Baik, U.S.; Umemori, M.; Takahashi, 1.; Naga-saka, H.;10. Sugawara, .1.; Baik, U.S.; Umemori, M.; Takahashi, 1.; Naga-saka, H.;
Kawamura, H.; and Mitani, H.: Treatment and post-treatment dentoalveolar changesKawamura, H.; and Mitani, H.: Treatment and post-treatment dentoalveolar changes
following intrusion of mandi-bular molars with application of a skeletal anchoragefollowing intrusion of mandi-bular molars with application of a skeletal anchorage
system (SAS) for open bite correction, Int. J. Adult Orthod. Orthog. Surg. 17:243-253,system (SAS) for open bite correction, Int. J. Adult Orthod. Orthog. Surg. 17:243-253,
2002.2002.

 11. Sherwood, K.H.; Burch, J.G.; and Thompson, W.J.: Closing anterior open bites by11. Sherwood, K.H.; Burch, J.G.; and Thompson, W.J.: Closing anterior open bites by
intruding molars with titanium miniplale anchorage, Am. J. Orthod. 122:593-600,intruding molars with titanium miniplale anchorage, Am. J. Orthod. 122:593-600,
2002.2002.
 12. Park, Y.C.; Lee, S.Y.; Kirn, D.H.; and Jee, S.H,: Intrusion of posterior teeth using12. Park, Y.C.; Lee, S.Y.; Kirn, D.H.; and Jee, S.H,: Intrusion of posterior teeth using
mini-screw implants. Arn. J. Orthod. 123:690-694, 2003.mini-screw implants. Arn. J. Orthod. 123:690-694, 2003.
 13. Kyung, H.M.; Park, H.S.; Bae, S.M.; Sung, J.H.; and Kirn, I.E.: Development of13. Kyung, H.M.; Park, H.S.; Bae, S.M.; Sung, J.H.; and Kirn, I.E.: Development of
orthodontic micro-implants for intraoral anchorage, J. Clin. Orthod. 37:321-328, 2003.orthodontic micro-implants for intraoral anchorage, J. Clin. Orthod. 37:321-328, 2003.
 14. Kanomi, R.: Mini-implant for orthodontic anchorage, J. Clin. Orthod. 31:763-767,14. Kanomi, R.: Mini-implant for orthodontic anchorage, J. Clin. Orthod. 31:763-767,
1997.1997.
 15. Costa, A.; RalTaini, M.; and Melsen, B.: Miniscrews as ortho-dontic anchorage: A15. Costa, A.; RalTaini, M.; and Melsen, B.: Miniscrews as ortho-dontic anchorage: A
preliminary report, Inl. J. Adult Orthod. Orthog. Surg. 13:201-209, 1998.preliminary report, Inl. J. Adult Orthod. Orthog. Surg. 13:201-209, 1998.
 16. Park, H.S.; Bae, S.M.; Kyung, H.M.; and Sung, J.H.: Micro-Implanl Anchorage for16. Park, H.S.; Bae, S.M.; Kyung, H.M.; and Sung, J.H.: Micro-Implanl Anchorage for
treatment of skeletal Class I bialveolar protrusion, J. Clin. Orthod. 35:417-428, 2001.treatment of skeletal Class I bialveolar protrusion, J. Clin. Orthod. 35:417-428, 2001.
 17. Bae, S.M.; Park, H.S., Kyung, H.M.; Kwon, O.W.; and Sung, J.W.: Clinical17. Bae, S.M.; Park, H.S., Kyung, H.M.; Kwon, O.W.; and Sung, J.W.: Clinical
application of Micro-Implant Anchorage, J. Clin. Orthod. 36:298-302, 2002.application of Micro-Implant Anchorage, J. Clin. Orthod. 36:298-302, 2002.
 18. Deguchi, T.; Takano-Yamamoto, T.; Kanomi, R.; Harlsfield, J.K. Jr.; Roberts,18. Deguchi, T.; Takano-Yamamoto, T.; Kanomi, R.; Harlsfield, J.K. Jr.; Roberts,
W.E.; and Garetto, L.P.: The use of small tita-nium screws for orthodontic anchorage,W.E.; and Garetto, L.P.: The use of small tita-nium screws for orthodontic anchorage,
.1. Dent. Res. 82:377-381,2003..1. Dent. Res. 82:377-381,2003.
 19. Nkenke, E.; Lehner, B.; Weinzierl, K.;Thams, U.; Neugebauer, J.; Steveling, H.;19. Nkenke, E.; Lehner, B.; Weinzierl, K.;Thams, U.; Neugebauer, J.; Steveling, H.;
Radespiel-Troger, M.; and Ncukam, F.W.: Bone contact, growth, and density aroundRadespiel-Troger, M.; and Ncukam, F.W.: Bone contact, growth, and density around
 immediately loaded implants in the mandible of minipigs, Clin. Oral Implants Res.immediately loaded implants in the mandible of minipigs, Clin. Oral Implants Res.
14:312-321,2003.14:312-321,2003.
 20. Ohmae, M.; Saito, S.; Morohashi, T.; Seki, K.; Qu, H.; Kanomi, R.; Yarnasaki, K.I.;20. Ohmae, M.; Saito, S.; Morohashi, T.; Seki, K.; Qu, H.; Kanomi, R.; Yarnasaki, K.I.;
Okano, T.; Yamada, S.; and Shibasaki, Y.: A clinical and histological evaluation ofOkano, T.; Yamada, S.; and Shibasaki, Y.: A clinical and histological evaluation of
titanium mini-implants as anchors for orthodontic intrusion in the bea-gle dog, Am. J.titanium mini-implants as anchors for orthodontic intrusion in the bea-gle dog, Am. J.
Orthod. 119:489-497, 2001.Orthod. 119:489-497, 2001.
 21. Gedrange, T; Bourauel, C.; Kobel, C; and Herzer, W.: Three-dimensional analysis21. Gedrange, T; Bourauel, C.; Kobel, C; and Herzer, W.: Three-dimensional analysis
of endosseous palatal implants and bones after vertical, horizontal, and diagonalof endosseous palatal implants and bones after vertical, horizontal, and diagonal
force application, Eur. J. Orlhod. 25:109-115, 2003.force application, Eur. J. Orlhod. 25:109-115, 2003.
 22. Carano, A.; Ciocia, C.; and Farronato, G.: Use of lingual brack-ets for deep-bite22. Carano, A.; Ciocia, C.; and Farronato, G.: Use of lingual brack-ets for deep-bite
correction, J. Clin. Orthod. 35:449-450, 2001.correction, J. Clin. Orthod. 35:449-450, 2001.

 23. Bowman, S..I. and Carano, A.: The Kilroy Spring for impacted teeth, J. Clin.23. Bowman, S..I. and Carano, A.: The Kilroy Spring for impacted teeth, J. Clin.
Orthod. 37:683-868, 2003.Orthod. 37:683-868, 2003.
 24. Becker, A. and Chaushu, S.: Success rate and duration of orthodontic treatment24. Becker, A. and Chaushu, S.: Success rate and duration of orthodontic treatment
for adult patients with palalally impact-ed maxillary canines, Am. J. Orthod. 124:509-for adult patients with palalally impact-ed maxillary canines, Am. J. Orthod. 124:509-
514, 2003.514, 2003.
 25. Park, H.S.: Intrusion molar con aclaje de microimplantes (MIA, Micro-Implant25. Park, H.S.: Intrusion molar con aclaje de microimplantes (MIA, Micro-Implant
Anchorage), Ortod. Clin. 6:31-36, 2003.Anchorage), Ortod. Clin. 6:31-36, 2003.
 26. Carano, A. and Machata, W.C.: A rapid molar intruder for "non-compliance"26. Carano, A. and Machata, W.C.: A rapid molar intruder for "non-compliance"
treatment, J. Clin. Orthod. 36:137-142, 2002.treatment, J. Clin. Orthod. 36:137-142, 2002.
 27. Gianelly, A.A.; Vaitas, A.S.; Thomas, W.M.; and Berger, D.G.: Distalizalion of27. Gianelly, A.A.; Vaitas, A.S.; Thomas, W.M.; and Berger, D.G.: Distalizalion of
molars with repelling magnets, J. Clin. Orthod. 22:40-44, 1988.molars with repelling magnets, J. Clin. Orthod. 22:40-44, 1988.
 28. Hilgers, J.J.: The Pendulum appliance for Class II non-compli-ance therapy, .1.28. Hilgers, J.J.: The Pendulum appliance for Class II non-compli-ance therapy, .1.
Clin. Orthod. 26:706-714, 1992.Clin. Orthod. 26:706-714, 1992.
 29. Wilson, W.L.: Modular orthodontic systems: Part 1, J. Clin. Orlhod. 12:259-278,29. Wilson, W.L.: Modular orthodontic systems: Part 1, J. Clin. Orlhod. 12:259-278,
1978.1978.
 30. Locatelli, R.; Bednar, J.; Dietz, V.S.; and Gianelly, A.A.: Molar distalization with30. Locatelli, R.; Bednar, J.; Dietz, V.S.; and Gianelly, A.A.: Molar distalization with
superelastic NiTi wire, J. Clin. Orthod. 26:277-279, 1992.superelastic NiTi wire, J. Clin. Orthod. 26:277-279, 1992.
 31. Gianelly, A.A.; Bednar, J,; and Dietz, V.S.: Japanese NiTi coils used to move31. Gianelly, A.A.; Bednar, J,; and Dietz, V.S.: Japanese NiTi coils used to move
molars distally, Am. J. Orthod. 99:564-566, 1991.molars distally, Am. J. Orthod. 99:564-566, 1991.
 32. Jones, R.D. and White, J.M.: Rapid Class II molar correction with an open-coil jig,32. Jones, R.D. and White, J.M.: Rapid Class II molar correction with an open-coil jig,
J. Clin. Orthod. 26:661-664, 1992.J. Clin. Orthod. 26:661-664, 1992.
 33. Carano, A. and Testa, M.: The Distal Jet for upper molar dis-talization, J. Clin.33. Carano, A. and Testa, M.: The Distal Jet for upper molar dis-talization, J. Clin.
Orthod. 30:374-380, 1996.Orthod. 30:374-380, 1996.
 34. Carano, A.; Testa, M.; and Bowman, S.J.: The Distal Jet sim-plified and updated,34. Carano, A.; Testa, M.; and Bowman, S.J.: The Distal Jet sim-plified and updated,
J. Clin. Orthod. 36:586-590, 2002.J. Clin. Orthod. 36:586-590, 2002.
 35. Bolla, E.; Muratore, K; Carano, A.; and Bowman, S.J.: Evalua-tion of maxillary35. Bolla, E.; Muratore, K; Carano, A.; and Bowman, S.J.: Evalua-tion of maxillary
molar distalization with the Distal Jet: A com-parison with other contemporarymolar distalization with the Distal Jet: A com-parison with other contemporary
methods, Angle Orthod. 72:481-494,2002.methods, Angle Orthod. 72:481-494,2002.

Clinical application of mas

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Semelhante a Clinical application of mas

Semelhante a Clinical application of mas (20)

Mais de Indian dental academy

Mais de Indian dental academy (20)

Último

Último (20)

Clinical application of mas