This document discusses intraoperative and postoperative orthodontic considerations for orthognathic surgery. It covers topics such as: - Ensuring brackets are reliably ligated to avoid debonds during surgery. Repairs may be needed intraoperatively or postoperatively. - Immediate postoperative care including checking the occlusion and taking radiographs to confirm proper positioning of the jaws and condyles. - Beginning active orthodontic treatment 2 weeks post-surgery with light guiding elastics worn full-time to guide the occlusion. - Selecting flexible working archwires to allow for vertical extrusion of teeth as needed to improve the occlusion.

1. Intraoperative and
postoperative orthodontics
for orthognathic surgery
BY
PROF DR MAHER FOUDA
FACULTY OF DENTISTRY
MANSOURA EGYPT

2. Intraoperative orthodontic
requirements
Surgical finesse is vital, and excessive surgical force
in placement of intermaxillary fixation may debond
brackets. Nevertheless, debonds do occur intraoperatively,
and can usually be ignored (hence the
importance of reliable ligation) and repaired by the
orthodontist postoperatively.

3. However, if a band
which is part of an RME appliance becomes loose, it
may need to be repaired intraoperatively. Additionally,
in segmental surgery, continuous archwires may
need to be placed intraoperatively, or over tied to the
segmented archwires, once the jaw has been surgically
segmented and repositioned. Therefore,
the presence of an orthodontist may occasionally
be required in the operating theatre.
An auxiliary archwire has been ligated over the main archwire.

4. A number of inaccuracies may occur during splint
wafer construction, and, as such, the fact that a patient
is occluding well into the surgical wafer is no guarantee
that they will occlude well once the wafer has been
removed. Wafers should be removed at the end of the
operation, and the dental occlusion checked.

5. Immediate postoperative
appointment
The patient should be seen by the orthodontist,
together with the surgeon, on the day following
surgery. It is important for patients to be mobilized as
soon as possible following surgery. As such, it is better
for patients to come from the ward to the maxillofacial
department, walk and sit in the dental chair to be
examined.

6. Surgical splint in maxillary arch. Mouth opening exercise
should be taught for oral function rehabilitation using
some elastics. Mouth opening enough for functional
recovery and forthcoming orthodontic treatment should
be obtained.

7. At this stage, the vast majority of patients feel
absolutely terrible. Though they should have been
informed preoperatively, it is important to reiterate to
the patient that the first few days are always the worst,
and that they will feel much better soon.
A = postsurgical intermaxillary fixation;
B = mouth opening width on removal of the intermaxillary fixation;
C and D = function rehabilitation with the modification of the occlusal
splint;

8. Despite
feeling dispirited, this encouraging information will
hearten the patient and their parents/carer.
E = occlusal stabilization;
F, G and H = selective grinding of teeth to finalize the occlusion.

9. The main purpose of this appointment is to check that
the skeletal and dental-occlusal aims of the surgery have
been achieved .

12. When to remove the wafer?
Traditionally, prior to the advent of rigid internal
fixation (RIF), postoperative immobilization
of the bimaxillary complex was required during
the 6-8 week bone healing phase. Therefore, the
final wafer was maintained in position, with the
patient in intermaxillary fixation (IMF), while the
wire osteosynthesis maintained the bone segments
together until bony union occurred.
Intra-operative photographs of (a) final and (b) intermediate
wafers in situ during mandibular and maxillary osteotomies,
respectively

13. Since the introduction
of RIF, some authorities continue to advise
the maintenance of the wafer tied to one or other
arch, for up to one month, in order to reduce the
risk of movement between the bone segments and
potential risk of fibrous union. Placing heavy intermaxillary
elastics in the first few weeks postoperatively
may risk fibrous union, and should be
avoided. However, maintaining the
wafer in situ has a number of downsides:
(A and B) 3D virtual models were
constructed and mounted into the
virtual articulator. They were
repositioned according to the STO
using the 3D Virtual Model Surgery
program . (C) A 3D
virtual wafer (3D-VIW) was constructed
using a stereolithographic technique

14. Patients dislike them – When a wafer is removed
postoperatively, the look of relief on a patient’s
face says it all.
Oral hygiene hazard – Dental plaque and food
debris is trapped between the teeth and wafer,
and the stench of the wafer when removed even
after one week can be nauseating.
The actual occlusal result is unknown – The clinician
only knows that the patient is occluding well
into the wafer .
Surgical splint in maxillary arch.
Mouth opening exercise should
be taught for oral function
rehabilitation using some
elastics. Mouth opening enough
for functional recovery and
forthcoming orthodontic
treatment should be obtained.

15. For these reasons, unless segmental maxillary
surgery has been undertaken, it may be advisable
to remove the wafer in theatre at the end of the
operation, and check the dental occlusion. Light
intermaxillary guiding elastics may be placed
as required. As long as untoward forces are not
placed in the first few weeks postoperatively,
the RIF maintains the bone segments together
permitting bony union, and the patient is far more
comfortable.
(a) Final CAD/CAM
surgical splint. (b)
Intermediate
CAD/CAM surgical
splint.

16. The patient is then sent for postoperative
radiographs
prior to returning for placement of intermaxillary
guiding elastics as required.

17. Postoperative radiographs
Following the clinical examination, the patient should
have an orthopantomograph (OPT) and possibly a
lateral cephalometric radiograph taken and critically
compared with the preoperative radiographs. These
radiographs are used to check:
Postoperative condylar position.
The alignment of the bony borders in the surgical
regions.
Pretreatment, postsurgical,
and 7-year posttreatment
cephalometric superimposition
(S-N).

18. One day postoperative
radiographs. (a) OPT to check
alignment of the bony borders in
the surgical regions and the
position of the condyles in the
glenoid fossae bilaterally. (b)
Preoperative lateral
cephalometric
radiograph may be compared
with the (c) postoperative lateral
cephalometric radiograph, again
checking for bony alignment and
condylar positions.

19. On the day
following surgery the patient was
occluding but with a lateral
displacement. Postoperative
radiographs demonstrated that the
right condyle was dislocated, and
the patient was taken back to
theatre. Recovery was uneventful,
but this case highlights the
importance of accurate
postoperative radiographs.
(a) Preoperative lateral
cephalometric radiograph prior to
bimaxillary surgery. The patient
left the operating theatre still
intubated due to intraoperative
complications

20. Lateral cephalometric radiograph taken 1 day
postoperatively to check chin relationships
following a set-back
genioplasty.
Chin position after a genioplasty.

21. The fact that a patient is occluding well into the splint
wafer is no guarantee that their dentition will be occluding
well together when the wafer has been removed. In fact,
maintenance of the final splint in situ potentially hides
a bad occlusion .
One day postoperatively the wafer has been
removed to reveal a poor dental occlusion and an occlusal
interference on the left canine and premolar region.

22. However,
if a major discrepancy in the position of the jaws is
observed, the patient will almost certainly need to
return to the operating theatre for surgical adjustment
as required. Attempting excessive intermaxillary elastic
placement with heavy forces, almost akin to intermaxillary
fixation, is inappropriate, and should be avoided.
A) Example of a high angle
case with mandibular
retrusion and anterior open
bite demonstrating relapse of
the orthognathic surgical
correction of a severe
anterior open bite. (B) Extra
and intraoral photographs
before orthognathic surgical
treatment after orthognathic
surgical treatment (C) and 2
years after orthognathic
surgical treatment.

23. If the
jaws have been rigidly fixed in an incorrect position,
no amount of orthodontic elastics will correct this
position, and one is simply delaying the inevitable.
Additionally, immediate return to surgery, though
unwelcome news for the patient, will be preferable to
reoperating after a few weeks, both psychologically
for the patient, and for the clinician, as bone healing
may occur very quickly in a young healthy adult, as
any surgeon attempting to reoperate after a few weeks
will testify.
postsurgical
intermaxillary
fixation

24. Postoperative orthodontics
Whether the wafer is removed early or not, active
orthodontic treatment is usually delayed for 2 weeks,
until the patient feels up to having treatment. During
this time the patient will usually be wearing light
intermaxillary guiding elastics, which help to guide
the patient into the planned dental occlusion. These
should be worn full time, and the patient should be
seen by the surgeon and orthodontist weekly for the
first 2 weeks, for close observation of any changes to
the dental occlusion.

25. (a) One day postoperative assessment reveals wafer
in situ and rather overzealous(excessive) intraoperative intermaxillary
elastic placement. (b) The wafer is removed and light
intermaxillary guiding elastics, also known as training
elastics, are placed to override the proprioceptive impulse of
minor dental or soft tissue interference and gently guide the
patient’s teeth into occlusion. Ideally, this should have been
carried out at the end of the operation.

26. One day postoperatively the wafer has been
removed to reveal a poor dental occlusion and an
occlusal
interference on the left canine and premolar region.

27. Some patients will have an obvious,
well-interdigitated dental occlusal result
postoperatively.
However, others may need closer observation,
with variations in the intermaxillary elastic vectors
made as required during this time.
presurgical orthodontic preparation
Pretreatment intraoral photographs: frontal,
lateral and occlusion of Class III malocclusion
Immediate postoperative intraoral views: the use of surgical
arch wires along with controlled elastic therapy and
exercise programs after fixation, greatly facilitate treatment

28. Repairs to the orthodontic appliance should be
made as soon as practically possible during this initial
period. If a bracket has debonded or a band is
loose, it should be repaired or removed.

29. If full thickness stainless steel archwires had been
placed prior to surgery, i.e. 0.0215 × 0.025-inch archwire
in a 0.022 × 0.028 bracket slot, then these stabilizing
archwires will need to be replaced with working
archwires..

30. This phase was begun three-weeks after the
orthognathic surgery was performed with the
aim of taking advantage of the RAP (regional
acceleratory phenomenon). 0.016” x 0.022”
NiTi termal archwires were placed with ¼” 4.5 oz
N-shaped settling elastics with a class III vector. For
finishing and detailing a 0.019” x 0.022” stainless
steel archwire was placed to express the appliance
prescription
Postsurgical phase

31. However, most orthognathic surgeons
are happy to operate with a larger dimension stainless
steel working archwire, e.g. 0.019 × 0.025-inch stainless
steel archwire, so long as it has been placed at
least 4 weeks prior to the maxillofacial technologist’s
impressions in preparation for surgery. If a working
archwire is already in place, there is no requirement to
change it at this stage

32. Working archwires
The type of working archwire required in either the
maxillary or mandibular arch depends on the tooth
movements desired. Often the most important initial
movement is to guide the teeth vertically into a better
dental occlusion.

33. The orthodontist must decide on
the teeth they would like to extrude, and in which
arch. For example, if the maxillary arch is level,
the
0.019 × 0.025-inch stainless steel archwire may
be
maintained in position.

34. If the mandible has been
advanced to a 3-point landing, the mandibular canines
and premolars need to be extruded by elastic force;
therefore a flexible mandibular archwire is required.
The dimensions and material of the flexible archwire
depend on the other types of movement that may
be required, e.g. torque control, but the following are
commonly used postoperatively:

35. Braided (multistrand) stainless steel – 0.017, or 0.018
or 0.019 × 0.025-inch .
TMA(titanium-molybdenum alloy) – 0.017, or 0.018
or 0.019 × 0.025-inch.
Nickel–titanium (NiTi) – 0.017, or 0.018 or
0.019 × 0.025-inch.
Features and Benefits:
• Gives torque control
• Eight thin wires woven into a strand
• Greater resiliency. Rectangular wire exerts very low
continuous force.
For early torquing, rotational control and finishing
•Accepts adaptation bends without
breakage
•Nickel–Free
•Force levels 45% less than those of
equivalent stainless steeL

36. A braided (multistrand) stainless steel archwire has
been placed in the mandibular arch postoperatively. The
dimension of the archwire is 0.019 × 0.025-inch and, as such, the
rectangular wire will maintain the torque. However, unlike the
rigid surgical archwire, this braided steel wire is flexible, and
box type elastics against the rigid stainless steel maxillary
archwire will permit extrusion of the mandibular dentition and
improvement of the occlusion.

37. Postsurgical second phase of class III as an example
Postsurgical follow-up was six weeks in
convalescence with intermaxillary splinting due to
the type of mandibular surgery. Afterwards, surgical
archwires were withdrawn and a re-leveling was
performed. To that end, 0.016 x 0.022 NiTi archwires
were placed and the patient was instructed to use M
elastics. Subsequently, 0.019 x 0.025 NiTi upper and
lower archewires were placed for three weeks. In the
consolidation phase, 0.019 x 0.025 stainless steel
archwires were placed for five weeks to fully express
the system’s prescription. Occlusal settlement was
done with a 0.019 x 0.025 braided archwire.
CASE REPORT 1

38. If further lingual inclination of mandibular molars is
desired, a flexible round archwire may be used, or a
smaller dimension round stainless steel
archwire (e.g.
0.018-inch).
In the transverse plane, further arch
coordination
may be required, as may further buccal root
torque of
the maxillary molars.

39. The mechanism of transverse decompensation
immediately after surgery. In most Class III cases, occlusal
interferences between functional cusps of the upper and lower
molars occur immediately after mandibular setback osteotomy
because of transverse dental compensation.

40. To remedy this problem, transverse
decompensation by constriction of the upper arch
and expansion of the lower arch is required.

41. After constriction of the upper arch and expansion of
the lower arch. The correction of the cusp to fossa
relationship at the posterior teeth is responsible on
the counterclockwise rotation seen during the
orthodontic phase.

42. Kobayashi ligatures
As described previously, these are very useful means
of attachment for orthodontic elastics, and should be
placed as required.

43. Intermaxillary working elastics
The configuration of the working intermaxillary elastics
depends on the type and direction of desired tooth
movement. Incorrectly placed elastics will result in
undesirable tooth movement; therefore, every effort
must be made to ensure that patients do not incorrectly
position them. A drawing demonstrating exactly
which teeth should engage the elastics may be provided
to the patient as a reminder.

44. Configurations and vectors for intermaxillary
working elastics
Vertical tooth movement in the buccal segments is
usually
facilitated with box elastics, maintaining a vertical
vector as far as possible .
Vertical tooth movement in the buccal segments may
be facilitated with box elastics, maintaining a vertical vector as
far as possible. The position of surgical hooks, integrated hooks
on brackets and Kobayashi ligatures allows the orthodontist to
vary the elastic vectors as required.

45. Vertical
intermaxillary elastics, whether box type or triangular
in configuration, aim at extrusion of selected teeth
to improve the interdigitation of the dental arches.
Box elastics are required to level a mandibular curve
of Spee.

46. If necessary, a Class II
vector may be advisable on one or both sides,
depending on the desired tooth movements.

47. If necessary, a Class II or
Class III vector may be advisable on one or both sides,
depending on the desired tooth movements.
Two months after surgery (lateral view). A, Rectangular nickel-titanium (Ni-Ti)
archwires were engaged and intrusion and distalization of maxillary molars and
protraction of mandibular dentition were carried out. The occlusal splint was
discontinued at that time. B, Skeletal anchorage system (SAS) biomechanics are also
applied at this stage. The photo shows SAS biomechanics that were applied to the
patient. In combination with intrusion and distalization of maxillary dentition and
protraction of mandibular dentition, the patient’s Class II denture will be improved
quickly.

48. Class II or Class III elastics may be placed with an
additional vertical vector, which is particularly
useful
following surgery to correct an anterior
open bite .
Following maxillary advancement and mandibular
set-back for a Class III patient with an anterior open bite, Class
III elastics are placed with an anterior vertical vector.

49. Short intermaxillary elastics, either Class
II or Class III, may be useful, providing the Class
II or III vector but limiting the potential detrimental
vertical eruption of the maxillary or mandibular
molars from routine Class II or III intermaxillary elastics.
These may also be placed in a triangular configuration
Short triangular intermaxillary elastic
with a Class
III vector.

50. Persistent dental midline deviations may require a
Class II elastic vector on one side and Class III on
the contralateral side. Sometimes an anterior diagonal
elastic may also be added (usually just night times).
In such situations, care must be taken not to cause
transverse canting of the maxillary occlusal plane by
extruding the teeth attached to these elastics; theoretically
temporary anchorage devices may be used in one
arch as a means of elastic attachment instead of the
teeth, though in practice this is rarely required.
Triangle intermaxillary elastics are oriented
diagonally to
correct the upper midline discrepancy during the
final stage
of active treatment.

51. Variations of postoperative
working elastic configurations
.
Examples of commonly required
postoperative working elastic configurations
for elastic traction. Archwires are not
shown to improve clarity, except partially
where archwire hooks are shown. It should
be noted that elastics may be placed around
archwire hooks or integrated bracket hooks
as required. Various other combinations and
configurations may be used as required.
(a) Class II elastic. (b) Class III elastic. (c)
Short Class II elastic –useful for Class II
correction whilst avoiding molar extrusion
and
anterior bite opening. (d) Short Class III
elastic –useful for Class III correction whilst
avoiding molar extrusion and anterior bite
opening.

52. (e) Class II elastic with vertical
element (Delta Class II) – useful
for Class II correction following
anterior open bite
correction. (f) Class III elastic
with vertical element (Delta
Class III) – useful for Class III
correction following anterior
open bite
correction. (g) Box elastic –
useful for closure of lateral or
posterior open bites, and active
occlusal ‘settling’. (h) Box
elastic with Class
II vector – as with (g), but when
Class II element required.

53. (i) Box elastic with Class III
vector – as with (g), but when
Class III
element required. (j) Triangular
elastic – these may be used as
guiding elastics
postoperatively, or as working
elastics, and placed
between any group of
opposing teeth, as required. (k)
Anterior diagonal elastic, with
Class II and Class III elastic
traction, which is a
combination commonly used
for dental midline correction.

54. Specific considerations following maxillary
expansion
When significant maxillary expansion has been
achieved, whether surgically or orthodontically, a
slightly expanded (∼3 mm per side) rectangular
stainless steel maxillary archwire should be maintained
during the postoperative phase of treatment. If
vertical settling of the maxillary teeth is also required,
a heavy expanded wire may be tied over the working
archwire, and placed into the headgear tubes, in
order to maintain the expansion .
An auxiliary
archwire has
been ligated
over the main
archwire.

55. Alternatively, a two-part maxillary wafer may be
used, such that when the main wafer is removed, a
palatal acrylic section is maintained, in order to retain
the expansion .
Atwo-part wafer was used, and the palatal part has
been maintained in situ following maxillary
expansion.

56. Orthodontic ‘salvage’(rescued)
Occasionally, the exact planned surgical result may not
have been attained. Where the discrepancy with the
planned result is relatively minor, and the facial aesthetic
improvements are acceptable, the orthodontist
and surgeon may decide if the case can be ‘salvaged’
by orthodontic treatment..
Dental relationship before
orthodontic treatment
Dental relationship after
orthodontic decompensation.
(Exaggerated reverse overjet
visible)
Dental relationship after surgery

57. Poor inter digitation between the upper
and lower teeth is often responsible for
relapse after surgery and hence an
unfavourable outcome.
Unilateral cross-bite Unilateral cross-bite corrected post-orthodontics and surgery

58. This often involves some
form of compensatory tooth movement, particularly
in relation to incisor inclinations. For example, if a
Class II mandibular advancement has been slightly
over-advanced, with an edge-to-edge type incisor
relationship, Class III elastics may be used, perhaps
in conjunction with a round steel archwire in the
mandibular arch, to improve the incisor relationship

59. Alternatively, if a Class III case has a slightly edge to-
edge incisor relationship postoperatively, Class III
elastics may be beneficial in improving this relationship
whatever the circumstances, the
clinicians need to be aware that miracles are not possible,
and significant problems resulting from surgical
shortcomings may need further surgical modification.
Following a mandibular set-back, a slightly
edge-to-edge incisor relationship was corrected with Class III
elastics.

60. Space closure
In some patients, particularly low angle, deep overbite
patients with strong masseter muscles and
a well-interdigitated dental occlusion, preoperative
orthodontic space closure in the buccal segments may
be extremely difficult and time-consuming. However,
completion of space closure postoperatively may be
considerably easier, as the bite is opened.
extraction spaces were closed by sliding mechanics to gain an ideal incisor
inclination according to cephalometric surgical prediction tracing

61. Root ‘paralleling’
If segmental surgery has been undertaken, the roots of
the teeth on either side of the planned segmental surgical
cut will usually have been diverged.

62. (A) and (B) Subtle(fine) bends can be placed in the arch
wire (between the central and lateral incisor and between
the maxillary canine and first premolar bilaterally. There is
a natural root divergence between the lateral incisor and
canine making this site an efficient location for maxillary
segmentation.

63. (C) The force diagram from an open coil spring showing
that root convergence occurs as the crowns separate.
This should be avoided so that the orthodontist does
not make the surgeon’s job more difficult.

64. Either repositioning
of the brackets at slight angle or second order bends in the
archwire will be required to achieve correct root angulation
postoperatively. This is sometimes referred to as
‘root paralleling’, though the term is somewhat of a
misnomer as the objective is correcting the angulations
of the teeth, not necessarily making the roots parallel.

65. Orthodontic settling and finishing
Much of the active vertical orthodontic settling occurs
with the intermaxillary working elastics. Intermaxillary
elastic wear will be markedly reduced, if required
at all, in the finishing stages of orthodontic treatment.
Elastic wear should be completely stopped for at least
6 weeks prior to appliance removal, to ensure that a
stable result has been achieved.

66. Minor variations in tooth crown morphology combined
with minor variations in bracket position will
mean that some tooth repositioning by ‘artistic’ wire
bending is likely to be required in the finishing stages
of treatment.
the archwires
were bended to
improve
intercuspidation
(yellow arrows)

67. Occasionally, first-order bends to vertically
extrude specific teeth or second-order angulation
bends for the incisor teeth may be required, as is labial
or lingual root torque for specific teeth (usually
maxillary
lateral incisors).

68. The postoperative phase of orthodontic treatment
typically takes anything from 3 to 6 months,
depending
mainly on the degree of postoperative tooth
movement
required.

69. Case report :Postsurgical orthodontic phase: orthodontic
treatment was resumed three weeks after surgery using up &
down elastics for muscle control . The objective of this phase
was to achieve an ideal occlusion in terms of Canine Class,
overjet and overbite and the coincidence of dental midlines.
0.018” x 0.025 " NiTi archwires were used and the use of
elastics was continued. Subsequently, 0.019” x 0.025”
archwires SS were placed for closure of residual spaces and
0.019” x 0.025" braided archwires were placed for refinement
of intercuspation through elastics
Occlusal splint at the end of surgery. Elastics for control

70. Retention
There is an often-quoted aphorism in orthodontics:
‘Stability is not a problem in orthodontics; it is the problem in
orthodontics.’
Certain orthodontic tooth movements, e.g. significant
derotation of teeth or closure of a maxillary midline
diastema, are known to be relatively unstable and
thereby potentially problematic in the long-term. In
such cases the orthodontist may decide to place a
lingual or palatal bonded retainer , in
addition to removable retainers.
A palatal bonded retainer.

71. However, the fact
remains that the results of treatment in some patients
are more stable than others, and we have no way of
knowing who is in which camp. Therefore, all patients
require some form of long-term retention, and this
must be explained right at the beginning of treatment,
and emphasized in the process of obtaining informed
consent.

72. Over time patients will realise the stability
of their own dentition, and as long as retainer wear is
reduced very gradually, whenever the patient places
their retainer and it feels a little tight, they know their
teeth have moved a little and they can increase their
retainer wear for some time before reducing wear
again.
The Essix retainer is a vacuum-formed stent that is entirely made of transparent plastic that
fits over all or mostly all teeth in the jaw (a), and the occlusal view of the retainer (b).

73. Retention protocol
Retention protocols and regimes vary from unit to
unit. Retainers should ideally be made and fitted on
the same day as appliance removal, or at least within
1–2 days.

74. This first 3–4 months of close to full time wear
is to permit time for reorganization of the periodontal
ligament and supporting tissues.
Retainer wear begins close to full time,
except for eating and cleaning of the teeth and
retainers.

75. Wear may be
reduced to evening and nights only after 3–4 months,
and gradually onto nights only, which may be continued
for between 12 to 24 months. Certain orthodontic
tooth movements will require a longer period of full
time retention, e.g. derotation of teeth, and may even
require bonded retention.
The Jensen retainer with its typical labial arch wire for stabilization of the
maxillary incisors (a), and in (b), the occlusal view of the retainer

76. Realistically, many patients
reduce retainer wear gradually to every other night,
and eventually down to a few nights per week, which
should then be maintained on a long term basis. However,
for many patients the degree of stability of their
orthodontically repositioned teeth is difficult to know
with any degree of certainty; as such, the orthodontists’
advice is usually for patients to continue their
night time retainer wear indefinitely.

77. Types of retainer
Patients
may be given some choice as to the type of
removable
retainer.

78. Vacuum-formed, Essix type retainers (introduced
by the American orthodontist Dr John Sheridan)
have superior aesthetic qualities, but the patient’s
oral hygiene must be excellent, otherwise decalcification
may result. They are often not particularly sturdy
and may crack, wear and have to be remade after some
variable interval.

79. When maxillary expansion has been undertaken,
Hawley type retainers, introduced by Charles A.
Hawley (1861–1929) in 1908, are preferable as the
palatal acrylic helps to maintain the expansion and
prevent transverse relapse.

80. An alternative is a combined
retainer, the Hawlix or ‘aesthetic’ retainer,
which combines the anterior aesthetic advantage of
the Essix retainer and the palatal acrylic of the Hawley
retainer. This retainer is particularly useful following
treatment in cleft lip and palate patients in order
to improve the aesthetics of anterior maxillary dentoalveolar
cleft defects.

81. If mild relapse is predicted, features may be built
into the retainers to help provide ‘active’ retention.
For example, if maxillary arch expansion has been
undertaken and the transverse buccal relationship is
tenuous, with a risk of developing a posterior crossbite,
a midline expansion jackscrew can be placed in
the Hawley retainer, in case it is required to deal with
post debond relapse in the retention period.
Active’ retention – a
midline Hyrax-type
jackscrew
has been placed in the
Hawley retainer in
case transverse
expansion is required.

82. In cases where Class III relapse of the incisor relationship
is predicted, hooks may be placed on the
Adams clasps for the maxillary molars in a Hawley
retainer, and some form of hook either on a lower
Hawley retainer in the canine regions or on a lower
Essix retainer, for attachment of Class III elastics as
required .
‘Active’ retention – The Hawley retainers have been
modified with hooks to allow placement of Class III elastic
traction in this post-treatment patient in case of Class III relapse.

83. Natural vertical settling continues when retainer
wear is reduced to part time, particularly with retainers
that do not employ occlusal coverage. This is
why the dental occlusion sometimes looks even better
at the 1-year review appointment than at appliance
removal.

84. REFERENCE