surgery first approach

1. SURGERY FIRST APPROACH

2. CONTENTS
 INTRODUCTION
 HISTORICAL PERSPECTIVE
 CHALLENGES ASSOCIATED WITH CONVENTIONAL
ORTHOGNATHIC SURGERY CASES
 INDICATONS
 CONTRAINDICATIONS
 STEPS IN SFOA
 PREOPERATIVE PROCEDURES
 SURGICAL PROCEDURE
 POST SURGICAL PROCEDURE

3.  ADVANTAGES OF SFOA OVER THE
CONVENTIONAL APPROACH
 DISADVANTAFES OF SFOA
 COMPARISON OF CONVENTIONAL AND
SURGERY-FIRST ORTHOGNATHIC APPROACH
 CONCLUSION
 REFERENCES

4.  A combined orthodontic and orthognathic surgery
approach is accepted as the standard of care for patients
who have a severe skeletal jaw discrepancy with facial
asymmetry.
 One drawback is the prolonged presurgical treatment time
that typically worsens facial appearance and exacerbates
the malocclusion.
INTRODUCTION

5.  Recently, to address patient demand and satisfaction,
the Surgery first approach was introduced to
overcome some disadvantages associated with the
conventional surgical orthodontic approach.

6. Jeong Hwan Kim, Niloufar Nouri Mahdavie and Carla A. Evans. Guidelines for “Surgery First” Orthodontic
Treatment

7. The first orthognathic surgery procedure was performed by
Simon Hullihen in 1848.
J.B. Caldwell and G.S. Letterman in 1954, devised a
vertical osteotomy of the ascending ramus to allow for
setback of the mandible followed by direct wire fixation.
HISTORICAL PERSPECTIVE

8.  In 1957, Trauner and Obwegeser
introduced sagittal splitting ramus
osteotomy, which marked the
beginning of the modern era of
orthognathic surgery.
 Obwegeser was also the first to develop
LeFort osteotomy to move the maxilla
in all three dimensions, reporting a
large series of maxillary osteotomy
cases in 1969.
Hugo .L.Obwegeser

9.  1944 - Dingman reported cases receiving surgery before
orthodontics .
 1959 - Skaggs suggested that patients with minor dentition
problems may receive surgery before orthodontic treatment.
 1991 - Brachvogel et al. suggested the potential advantages
of a surgery-first approach.

10. 2009 - Nagasaka et al., popularized SFOA. Nagasaka et
al were among the first to actually carry out SFOA
using miniplates for post-surgical orthodontic treatment
Sugawara and Nanda published a series of case reports
using a SFA approach to correct skeletal Class III and
skeletal Class II malocclusion and dentofacial
asymmetry.
Choi et al. Current status of the surgery-first approach (part I): concepts and orthodontic protocols. Plast ReconstrSurg. (2019) 41:10

11. CHALLENGES ASSOCIATED WITH CONVENTIONAL
ORTHOGNATHIC SURGERY CASES
 Long treatment times of 7 - 47 months.
 Increased risk of enamel decalcification.
 Gingival recession and root resorption.
 Esthetic and functional drawbacks during the presurgical
orthodontic treatment.
S. Zingler et al Surgery-first approach in orthognathic surgery: Psychological and biological aspects – A prospective cohort study.Journal of
Cranio-Maxillo-Facial Surgery 45 (2017) 1293e1301.

12. INDICATIONS
The criteria that are suggested for Surgery First Approach are:
• Well-aligned to mild crowding.
• Flat to mild curve of Spee.
• Normal to mild proclination/ retroclination of incisors.
• Minimal transverse discrepancy.

13.  Even though, the surgery-first technique can be applied
to Class II as well as Class III malocclusions, the
majority of cases treated using this approach have been
cases with Class III malocclusion meeting the above
criteria.

14. CONTRAINDICATIONS
Patient who require definite decompensation
Severe crowding
Arch-incoordination
Severe vertical or transverse discrepancy
Severe proclination of upper and lower anteriors

15. FAVOURABLE AND UNFAVOURABLE
CASES

16. STEPS IN SFOA
Preoperativ
e procedures
Surgical
procedure
Post-
surgical
procedure

17. PREOPERATIVE PROCEDURES
Timing of bonding in SFOA
Stabilizing/ Initial arch wires in SFOA
Splints in SFOA
Laboratory procedures
Choi DS, Garagiola U, Kim SG. Current status of the surgery-first approach (part I): concepts and orthodontic protocols.
Maxillofacial plastic and reconstructive surgery. 2019 Dec;41(1):1-8.

18. TIMING OF BONDING IN SFOA
Sugawara and Nagasaka recommended that fixed orthodontic
appliances should be placed just before surgery even when using
a surgery first approach.
But the problem is, when brackets are attached immediately
before surgery the bond strength of bracket to teeth might be
weak and fail to resist the force of intermaxillary fixation.
Sugawara J, Aymach Z, Nagasaka H, Kawamura H, Nanda R, “Surgery First” Orthognathics to Correct a Skeletal Class II
Malocclusion with an Impinging Bite. J Clin Orthod 2010: 56 (7): 429-438.

19. Chung et al. recommended the brackets should be placed
1 week before orthognathic surgery.
Ellen Wen Ching recommended 1 month before surgery
Generally in most cases, the brackets and the wires are
placed right before surgery.
Yu CC, Chen PH, Liou EJ, Huang CS, Chen YR. A Surgery-first Approach in surgical-orthodontic treatment of mandibular
prognathism – a case report. Chang Gung Med J. 2010 Nov-Dec;33(6):699-705.

20. Federico Hernandez reported the total elimination of
preoperative orthodontic treatment and the fitting of
orthodontic brackets 10-14 days after surgery.
If these are not placed before surgery, placement in the
immediate postoperative period is often very difficult for the
patients because of swelling, discomfort and limited mouth
opening during this time.
Alfaro FH, Martínez RG, and Escriche CB. “Surgery First” in Bimaxillary Orthognathic Surgery. J Oral Maxillofac Surg 2011: 69: 201-207.

21. STABILIZING/ INITIAL ARCH WIRES IN SFOA
Most authors used stabilizing wires before surgery. Some
used NiTi wires and some used stainless steel wires.
Liou et al did not place any orthodontic archwires before
surgery.

22. Ching et al used 0.016x0.022” superelastic NiTi wire.
Carlos et al have opted to use 0.16” nickel-titanium wires at
time of surgery.
The use of nickel-titanium wires translates into immediate
tooth movement after surgery which can be an advantage.
Liou EJW, Chen PH, Wang YC surgery-first accelerated orthognathic surgery: postoperative rapid orthodontic tooth movement. J Oral
Maxillofac Surg 2011: 69: 781-785

23. Sugawara and Nagasaka preferred 0.18”x0.25” SS wires and
0.19”x0.25” SS wires in 0.022 slot are adapted to all teeth for
preventing any tooth movement.
Either brackets have hooks or brass wire (lugs) are soldered
to the arch wire for wiring fixation, prefabricated ball hooks
may also be used, kobayashi hooks can also be used.
Villegas C, Uribe F, Sugawara J, Nanda R. Expedited Correction of Significant Dentofacial Asymmetry Using a “Surgery First” Approach. J Clin
Orthod 2010: 56 (2): 97-103.

24. Alternatively, Baek et al suggested the archwire can be
bonded directly to tooth surfaces to function as an arch bar a
few days prior to surgery.
Although direct wire bonding is comfortable for the patient,
it is difficult to remove the bonded wire and replace with
brackets during the healing period.
Baek SH, Ahn HW, Kwon YH, Choi JY. Surgery-first approach in skeletal Class III malocclusion treated with 2- jaw surgery: evaluation of
surgical movement and postoperative orthodontic treatment. J Craniofac Surg. 2010: 21: 332–338.

25. SPLINTS IN SFOA
The use of surgical splint during and after surgery also varies
between different orthodontists.
While some advocate the use of the splint only during
surgery, other groups have advocated its use anywhere between
one to four weeks after surgery

26. Nagasaka et al have used removable Gelb–type splints
post operatively.
Their preference is to leave the splint in for about 4 to 6
weeks after surgery
Nagasaka H, Sugawara J, Kawamura H, Nanda R. surgery first skeletal class III correctionusing the skeletal anchorage system. J Clin Orthod
2009: 58 (2): 97-105.

27. Sugawara et al modified the surgical splint into a removable
maxillary occlusal splint, which was used to stabilize the jaw
position and masticatory function.
Sugawara J, Aymach Z, Nagasaka H, Kawamura H, Nanda R, “Surgery First” Orthognathics to Correct a Skeletal Class II
Malocclusion with an Impinging Bite. J Clin Orthod 2010: 56 (7): 429-438.

28. LABORATORY PROCEDURES
Pre-surgical procedure with the dental model is the most
important step in the surgery-first approach.
“Set-up models” are used to predict and simulate dental
positions and arch coordination for decision on surgical jaw
movement.

29. Liou et al suggested to set-up model surgery in proper
molar relationships with a positive overbite that is opposite
to the conventional approach which uses decompensated
incisors as the guide to predict the final occlusion.


30. The molar relationship could be
 Class I in cases of nonextraction or bimaxillary first premolar
extraction
Class III in cases of lower first premolar extraction
Class II in cases of maxillary first premolar extraction.
Once the molar relationship has been established, the overjet
should also have been determined

31. VIRTUAL SURGICAL PLANNING
 The demand for accuracy has driven the development of
computer assisted planning and splint fabrication.
 Very complex dentofacial deformities especially the
asymmetric cases can be planned using computer-assisted
surgical simulation and splints can be virtually fabricated

32. Treatment Planning Considerations
The molar relationship can be utilized as a starting point to
come up with a temporary occlusion.
The inclination of upper incisors is important in determining the
need for possible extractions. If the upper incisor to occlusal
plane angulation is <53-55°, extraction must be considered.
•Park KR,Kim SY,Park HS,Jung YS.Surgery-first approach on patients with temporomandibular joint
disease by intraoral vertical ramus osteotomy.Oral Surg Oral Med Oral Pathol Oral Radiol
2013;116:e429-36
•65..

33.  The midlines must be coincident or close to it after surgery, and
proper buccal overjet must be established bilaterally
 Depending on the degree of discrepancy between the two
arches, segmental osteotomies in more severe cases are
considered

34.  Most challenging and time consuming step is the prediction
of the final occlusion based on the current position of teeth.
 The term intended transitional malocclusion is used to
describe the occlusion that is used to fabricate the surgical
splint and surgeon's guide during surgery.
 At least a three-point contact must be established between
the upper and lower models when deciding ITM

35. TREATMENT CONSIDERATIONS IN SKELETAL CLASS II IN
SFOA
In these cases, the upper incisors are usually retroclined while
the lower incisors are commonly flared out.
SFOA may be particularly beneficial for a class II patient
with a retrusive mandible.
Sugawara J, Aymach Z, Nagasaka H, Kawamura H, Nanda R, “Surgery First” Orthognathics to Correct a Skeletal Class II
Malocclusion with an Impinging Bite. J Clin Orthod 2010: 56 (7): 429-438.

36. Immediately after surgery the Class II malocclusion
becomes a super class I or Class III relationship following
mandibular advancement, with an edge-to-edge incisor
relationship or bimaxillary dentoalveolar protrusion.
This situation therefore requires the use of class III
orthodontic mechanics or it can also be corrected by
extracting all first premolars followed by retraction as in
class I bimaxillary protrusion cases.

37. In class II division 2 cases it is difficult to perform SFOA
as there is a less overjet.
In such cases surgery can be performed after uprighting
the upper anteriors and after obtaining the sufficient overjet
for the advancement of mandible or surgery can also be
performed directly without presurgical orthodontics thereby
getting reverse overjet, which can be corrected post-
surgically.

38. TREATMENT CONSIDERATIONS IN SKELETAL CLASS III IN
SFOA
In these cases, the lower incisors are usually crowded and
retroclined while the maxillary incisors are commonly flared
out.
When surgery is performed first, a class III malocclusion
always become a class II relationship immediately after
mandibular setback which should be maintained with surgical
splint and requires class II orthodontic mechanics after surgery
and adjustment of the anterior teeth can be managed
postoperatively.
Nagasaka H, Sugawara J, Kawamura H, Nanda R. surgery first skeletal class III correctionusing the skeletal anchorage system. J Clin Orthod

39. Classification
Styles of surgery first approach- Recommended in 2003 at
Tohoku University in Sendai city of Japan
Kim JY, Jung HD, Kim SY, Park HS, Jung YS. Postoperative stability for surgery-first approach using
intraoral vertical ramus osteotomy: 12 month follow-up. Br J Oral Maxillofac Surg. 2014 July;52(6):539-44.
18.
Sugawara J, Aymach Z, Nagasaka DH, Kawamura H, Nanda R. “Surgery first” orthognathics to correct a
Orthodontically driven style
Surgically driven style
SURGICAL PROCEDURES

40. Surgically driven style: When the surgical treatment
is utilized not only for correction of skeletal problem
but also for the dental problem.
Orthodontically driven style: Corrects the jaw
deformity by surgery and the dental deformity via
orthodontics.

42. BASIC DEFORMITIES AND SURGICAL TREATMENT
PRINCIPLES
1. Mandibular anteroposterior deficiency,
2. Mandibular anteroposterior excess,
3. Maxillary anteroposterior deficiency,
4. Maxillary anteroposterior excess,
5. Maxillary vertical deficiency,
6. Maxillary vertical excess,
7. Cases requiring rotation of the maxillomandibular
complex.

43. Severe Class II
 Anteroposterior Maxillary Excess
 Mandibular anteroposterior deficiency
 Combination
Anteroposterior Discrepancy

44. Surgical correction Class II
 The clinician should carefully differentiate between maxillary
anteroposterior excess and mandibular anteroposterior
deficiency.
 An anterior segmental osteotomy of the maxilla is often
performed as part of a Le Fort I procedure.

45. The surgical technique of choice is the bilateral sagittal split
ramus osteotomy, which advances the distal (tooth-bearing)
segment to maximum dental intercuspation.

46. The position of the maxillary and mandibular incisors
controls both the amount the mandibular advancement
as well as the facial height after surgery.
The chin may still appear deficient after advancement
of the mandible, and an advancement genioplasty may
be indicated to improve final esthetics.

47. Severe Class III cases
 Maxillary anteroposterior deficiency
 Mandibular anteroposterior excess,
 Combination

48. Surgical treatment FOR CLASS III
 The maxilla is advanced by means of a Le Fort I osteotomy.
 This versatile procedure enables the surgeon to correct
discrepancies in the anteroposterior, vertical and transverse
planes.

49.  Bilateral sagittal split ramal osteotomy of the mandible is a
good option for reduction in mandibular length in skeletal
class III patients.
 Some cases with chin prominence may require genioplasty
also to achieve pleasant profile.

50. Transverse discrepancy
 Severe Cross-bite cases due to transverse jaw discrepancy or
TMJ disorders out of the scope of expansion appliances or
functional therapy.
 The intercanine and intermolar width of the upper and lower
arch are coordinated either by surgery or post surgical
orthodontics.

51.  Wide maxilla with a transverse discrepancy more than a
molar width on each side - Le Fort I osteotomy of the
maxilla.
 Wide maxilla with a transverse discrepancy less than a
molar width on each side - postoperative orthodontic tooth
movement.
 Narrow maxilla - surgically assisted rapid palatal
expansion

52. Vertical discrepancies
 Vertical maxillary excess
 Vertical maxillary deficiency
 Rotation of the maxillomandibular complex

53. To correct the vertical discrepancy, the maxilla must be
superiorly repositioned by a Le Fort I osteotomy.
Surgical treatment for Vertical Maxillary Excess :

54. Maxillary Vertical Deficiency
 Maxillary vertical deficiency is very often associated with
maxillary anteroposterior deficiency, in which the maxilla
does not develop in a forward and downward direction.

55.  The surgical treatment objective for patients with maxillary
vertical deficiency is to reposition the maxilla forward and
downward.
 The mandible will rotate clockwise, and the vertical height
of the face will increase.

56. Rotation of the Maxillomandibular Complex :
 Superior repositioning of the maxilla will cause the
mandible to rotate counterclockwise, inferior
repositioning of the maxilla will result in a clockwise
rotation of the mandible.

57. Two jaw surgery
 Two-jaw surgery may be indicated in patients with severe
Class II/III malocclusion.
 Here the orthodontist should adopt the “two-patient” concept,
in which the mandibular and maxillary arches are treated
independently, almost as if they belong to two different
patients; however, the two arches should still be compatible.

58. POSTOPERATIVE PROCEDURE IN SFOA
The objectives of orthodontic treatment after surgery in the
SFOA technique are dental alignment, arch coordination and
allow occlusal settling.
This period can speed up orthodontic tooth movement due
to Regional Acceleratory Phenomenon.

59. The surgical splint and intermaxillary fixations should be
removed for the tooth movement.
Leelasinjaroen et al suggested postsurgical orthodontic
treatment could begin as early as one week to one month
postoperatively.
Kim et al suggested to wait four to six weeks.
Kim JY, Junga HD, Kimb,SY, Parka HS, Junga YS Postoperative stability for surgery-first approach using intraoral vertical ramus osteotomy:
12 month follow-up. British Journal of Oral and Maxillofacial Surgery 2014: 52: 539– 544.

60. Nagasaka et al completed postoperative orthodontic
treatment within approximately 1 year.
Sugawara et al removed the fixed orthodontic therapy after
9 months.
Villegas C, Uribe F, Sugawara J, Nanda R. Expedited Correction of Significant Dentofacial Asymmetry Using a “Surgery First” Approach. J Clin
Orthod 2010: 56 (2): 97-103.
Sugawara J, Aymach Z, Nagasaka H, Kawamura H, Nanda R, “Surgery First” Orthognathics to Correct a Skeletal Class II
Malocclusion with an Impinging Bite. J Clin Orthod 2010: 56 (7): 429-438.

61. Villegas et al removed the fixed appliances 7 months after
surgery.
Treatment time was approximately 6-12 months shorter
using a surgery-first approach compared with using a
conventional orthodontics-first approach

62. ADVANTAGES OF SFOA OVER THE
CONVENTIONAL APPROACH
 Early correction of soft tissue problems.
 Minimize serious psychosocial difficulties encountered by
patients.
 Entire treatment period is shortened to 1 to 1.5 years or less.
 Phenomenon of RAP reduces the difficulty and treatment time
of orthodontic management.
 Compensation of surgical error or skeletal relapse is possible
later
 Earlier resolution of temporomandibular disorders and sleep
disordered breathing

63. PREVENTION OF SOFT-TISSUE PROFILE WORSENING IN
SURGERY FIRST ORTHODONTICS
 Decompensation in the first stage of the conventional
approach works against all of nature’s compensatory
mechanisms
 Surgical procedure is performed prior, the hard- and soft-
tissue imbalance is corrected; thus, the alignment of teeth is
done easily without the need to struggle with the biological
restraints

64. MINIMIZE SERIOUS PSYCHOSOCIAL DIFFICULTIES
ENCOUNTERED BY PATIENTS
 Undergoing surgical correction addresses
the chief complaint of the patient at the
very start of therapy.
 Patients have the possibility to select the
timing of surgery to accommodate for the
postsurgical recovery period.

65. REDUCTION IN DURATION OF TREATMENT
Two major factors:
1.The correction of the hard- and soft-tissue
disharmony before initiating tooth movement.
2. The regional acceleratory phenomenon (RAP).

66. REGIONAL ACCELERATORY PHENOMENON
 The regional acceleratory phenomenon (RAP) was well
described by Harold Frost in 1989
 After an osteotomy, bone remodeling around the healing
tissue facilitates the healing process.
 This regional acceleratory phenomenon can be utilized by the
orthodontist following orthognathic surgery to accelerate tooth
movement
Verna C. Regional acceleratory phenomenon. Kantarci A, Will L, Yen S (eds): Tooth Movement. Front Oral
Biol. Basel, Karger, 2016, vol 18, pp 28–35.

67. Studies shows that orthognathic surgery triggers 3 to 4
months of higher osteoclastic activities and metabolic
changes in the dentoalveolus.
RAP shows peak activity in 1 to 2 months after
surgery.

68. COMPENSATION OF SURGICAL ERROR OR SKELETAL
RELAPSE
If a surgical error or skeletal relapse occurs, compensation
can be made with skeletal anchorage system
 In conventional treatment, the decompensation is completed
before surgery, it is difficult or impossible to recover from
surgical error during postsurgical orthodontic treatment.

69. Early resolution of temporomandibular disorders and
sleep disordered breathing
• Significant number of temporomandibular disorder (TMD)
symptom resolution along with excellent results with the
surgical procedures of patients with mandibular prognathism
using SFA have been reported.
• Early advancement procedures help immediately increasing
the dimension of the upper airway. Hence resolution of
obstructive sleep apnea

70. DISADVANTAGES OF SURGERY FIRST APPROACH
 Predicting the final occlusion is the hardest challenge with surgery first
approach.
 The requirement for more surgical movement to compensate for
postoperative orthodontic movement.
 Without presurgical orthodontics, it is difficult to obtain a stable
occlusion immediately after surgery.
 Cases requiring extractions are especially very difficult to plan when
performing surgery first. Thus, case selection is of outmost importance.

71. COMPARISON OF CONVENTIONAL AND
SURGERY-FIRST ORTHOGNATHIC APPROACH

73. STABILITY
• More than 50% of SFOA patients with class III deformities may have more
than 2 mm of relapse at the pogonion, according to certain reports and some
SFOA patients had more relapses than the COSA (57.9% versus 26.3%) as
per some studies.

74.  A systematic review of systematic reviews was
conducted following criteria to evaluate any difference
between surgery first approach (SFA) and conventional
orthognathic approach (COA) in terms of skeletal
stability, treatment time, complications and quality of
life.

75. CONCLUSION
 A good stability of the jaws was assessed both with SFA and
COA.
 Less treatment time was reported for SFA than COA.
 Slightly higher complications rate was recorded with SFA
than COA.

76.  A better quality of life with SFA than COA was
reported.
 SFA may represent a reasonable alternative to COA.
 However, well-designed studies with a long term
follow-up are needed to clarify the findings of this
analysis.

77.  This study showed that the worsening of the facial profile
during the traditional orthognathic surgery approach had a
negative impact on the perception of patients quality of
life.
 Surgeons should consider the possibility of a surgery-first
approach to prevent this occurrence

78. Two major differences between the recent and
old protocol, exists, which are
• In the recent protocol, placement of brackets
and passive surgical wires is no longer
required before jaw surgery, and only
surgical hooks are needed to be bonded to
the lateral teeth.

79.  Further, the duration of surgical splint use has been
significantly shortened. Instead of a surgical splint, a
posterior build-up in the maxillary dentition is used to
secure a vertical stop.

80. CONCLUSION
Performing orthognathic surgery before orthodontic
treatment has multiple advantages including: shortened
treatment time, increased patient acceptance, and the
utilization of RAP.
 If the cases are selected carefully, the orthodontist and the
surgeon are experienced enough to predict the final
occlusion beforehand, and , the results can be very
promising

81. REFERENCES
Jeong Hwan Kim, Niloufar Nouri Mahdavie and Carla A.
Evans. Guidelines for “Surgery First” Orthodontic Treatment
Choi et al. Current status of the surgery-first approach (part I):
concepts and orthodontic protocols. Plast ReconstrSurg. (2019)
41:10
S. Zingler et al Surgery-first approach in orthognathic surgery:
Psychological and biological aspects – A prospective cohort
study.Journal of Cranio-Maxillo-Facial Surgery 45 (2017)
1293e1301.
Sugawara J, Aymach Z, Nagasaka H, Kawamura H, Nanda R,
“Surgery First” Orthognathics to Correct a Skeletal Class II
Malocclusion with an Impinging Bite. J Clin Orthod 2010: 56
(7): 429-438.
Alfaro FH, Martínez RG, and Escriche CB. “Surgery First” in
Bimaxillary Orthognathic Surgery. J Oral Maxillofac Surg
2011: 69: 201-207.

82. Liou EJW, Chen PH, Wang YC surgery-first accelerated
orthognathic surgery: postoperative rapid orthodontic tooth
movement. J Oral Maxillofac Surg 2011: 69: 781-785
Villegas C, Uribe F, Sugawara J, Nanda R. Expedited
Correction of Significant Dentofacial Asymmetry Using a
“Surgery First” Approach. J Clin Orthod 2010: 56 (2): 97-
103.
Nagasaka H, Sugawara J, Kawamura H, Nanda R. surgery
first skeletal class III correctionusing the skeletal anchorage
system. J Clin Orthod 2009: 58 (2): 97-105.
Kim JY, Jung HD, Kim SY, Park HS, Jung YS. Postoperative
stability for surgery-first approach using intraoral vertical
ramus osteotomy: 12 month follow-up. Br J Oral Maxillofac
Surg. 2014 July;52(6):539-44. 18.
Verna C. Regional acceleratory phenomenon. Kantarci A,
Will L, Yen S (eds): Tooth Movement. Front Oral Biol.
Basel, Karger, 2016, vol 18, pp 28–35.

83. THANK YOU