A Modified Surgery ApproAch MAndibulAr prognAthiSM ... · detailing of the occlusion. After treatment, the maxillary incisors proclination was corrected and all the dental spaces

86 Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 210.30036/TJO.201906_31(2).0003

Case Report

This case report describes the management of an adult patient presenting with a skeletal Class III

malocclusion, mandibular protrusion, upper incisor proclination and mandibular arch spacing by a modified

surgery-first approach. A 26-year-old man had skeletal Class III and dental Class III malocclusion with

concave facial profile, midface deficiency and mandibular prognathism with chin deviation to left. His dental

manifestation presented anterior crossbite, upper incisors proclination and spacing in his mandibular arch.

Treatment was performed with a modified surgery-first approach, which included a short presurgical alignment

phase. In the maxilla, the significant maxillary crowding was relieved by 14 and 24 extractions while partially

retracting the maxillary incisors to reduce the incisal proclination. Then, the upper incisors inclination was

furtherly corrected more by a 2-pieces LeFort I osteotomy and closure of the 14, 24 residual dental space

during surgery. In the mandible, the lower dental spacing was caused by general tooth size/ jaw bone

discrepancy with relative upright incisal inclination. The presurgical preparation included consolidation the

dental space distal to the bilateral mandibular canines. The bilateral sagittal split osteotomies were conducted

for mandible setback and asymmetry correction. Additionally, the subapical osteotomy with Köle procedure

was applied to close the dental space in the mandibular arch while keeping the anterior teeth in relative

normal inclination. The excessive chin prominence caused by the Köle procedure was reduced by reduction

genioplasty and surface contouring. Post-operative orthodontic treatment included overbite control and

detailing of the occlusion. After treatment, the maxillary incisors proclination was corrected and all the dental

spaces were closed. Patient’s profile was dramatically improved with well teeth alignment, angulation and

interdigitation. The 2-pieces LeFort I and Köle osteotomy are the surgical procedures to address the correction

in the dentoalveolar portion for efficiently control the inclination of the anterior teeth. Moreover, it also provides

benefits for patients who require large amount of jaw setback with minimal effect at the posterior airway space.

The treatment goals of the dentoalveolar portion and facial proportion should be contemplated for the staged

procedures to improve the efficiency and effectiveness of the treatment outcome. (Taiwanese Journal of Orthodontics. 31(2): 86-94, 2019)

Keywords: orthognathic surgery; modified surgery-first approach; skeletal Class III malocclusion; mandibular prognathism; segmental osteotomy.

A Modified Surgery-firSt ApproAch for MAndibulAr prognAthiSM with proclined MAxillAry inciSor And MAndibulAr SpAcing

Jutharath Chanruangvanich,1,2

Ellen Wen-Ching Ko,1,2,3

Ying-An Chen3,4

1Department of Craniofacial Orthodontics, Chang Gung Memorial Hospital, Taipei, Taiwan

2Graduate Institute of Dental and Craniofacial science, Chang Gung University, Taoyuan, Taiwan

3Craniofacial Research Center, Chang Gung University, Taoyuan, Taiwan

4Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan

Received: February 26, 2019 Accepted: March 5, 2019Reprints and correspondence to: Dr. Ellen Wen-Ching Ko, Department of Craniofacial Orthodontics, Chang Gung Memorial Hospital, Taipei, Taiwan. 6F, 199, Tung Hwa North Road, Taipei 105, Taiwan Tel: +886-2-27135211 ext.3533 Fax: +886-2-25148246 E-mail: [email protected]

87Taiwanese Journal of Orthodontics. 2019, Vol. 31. No. 210.30036/TJO.201906_31(2).0003

INTRODUCTION

A Class I I I ske le ta l pa t t e rn cou ld l ead to

malocclusion and disharmony facial profile. From the

systematic review and meta-analysis of Hardy et al. in

2012, the Angle Class III malocclusion had been found

in Southeast Asian population with the highest rate of

15.80% compare to other population.1 As well as the

study from Soha et al. in 2005, the relationships of Class

III incisor in Asian male army were 22.4% and Class III

molar relationship were 24.2 % at right side and 21.2%

at left side.2 Tang also reported the prevalence of Class

III malocclusion which was 14.8% in male dental student

in Hong Kong.3 Most of the Class III malocclusion also

presented a skeletal discrepancy (75.4%).4

Although mild skeletal discrepancy can be treated

by camouflage orthodontic treatment. To improve facial

profile and dental occlusion in severe skeletal relationship,

the treatment usually leads to orthognathic surgery.

For conventional orthognathic surgery, the presurgical

orthodontic treatment is needed to decompensate teeth

alignment before surgery which provides benefits of

changing the amount of surgical reposition procedure and

gives the best surgical results.5 However, patients who

received presurgical orthodontic treatment were found to

have negative impact on their quality of life.6

The surgery- first approach was introduced in 1988

by Behrman and Behrman with the advantages of short

treatment period due to no presurgical orthodontics

treatment stage.7 Patients also reported the improvement

of quality of life immediately after surgery in surgery-

first approach group.6 Yet in some cases, the degree

of complexity exceeds the limitation for surgery-first

approach.

A modified surgery-first approach has an advantage

of using short period of presurgical orthodontic

preparation simply for minor teeth adjustment. The aim

of dental correction prior the surgery is to decrease the

Mandibular Prognathism with Atypical Dental Pattern

amount of severe dental discrepancy such as excessive or

recessive inclination and major dental interference which

could impact the setting of surgical occlusion, still there

are some correction needed for postsurgical orthodontic

treatment to be done.

Furthermore, surgical techniques to enhance

dental correction can be benefit for patients who have

atypical skeletal and dental pattern. Segmental osteotomy

can be used to improve surgical outcome and help

occlusal set up instead of strictly relying on orthodontic

tooth movement. In the maxilla, the maxillary segmental

osteotomy provided stable outcomes in sagittal plane.8

With the rigid fixation and interpositional bone grafting,

the stability in horizontal plane of maxilla advancement

in segmental group is the same as one-piece group and

shows less relapse rate in vertical plane.9

For mandible, main reason of skeletal Class III

comes from mandibular prognathism (47.4%) or excessive

growth, meanwhile the maxilla found to be retrognathism

(10.5%) or micrognathia (8.8%).4 To deal with the

excessive mandible, mandibular setback by bilateral

sagittal split osteotomies (BSSO) is usually performed in

our centre. Still the large amount of setback could affect

the posterior airway space10,11

or could not fully correct

patient’s problem. The mandibular anterior segmental

subapical osteotomy was first introduced by Hullihen in

1849.8 After that many modification procedures by Köle

was introduced in 1959.12

The subapical osteotomy at

the anterior part of mandible provide more modification

on lower jaw such as adjusting incisal position, incisal

inclination and arch length.13,14

Therefore, this case report describes the management

of an adult patient presenting with a skeletal Class

III malocclusion with mandibular protrusion, upper

incisor proclination and mandibular arch spacing by a

modified surgery-first approach. The surgical technique

included segmental LeFort I osteotomy in maxilla and

BSSO combined with subapical osteotomy in mandible.


Chanruangvanich J, Ko EWC, Chen YA

CASE REPORT

A 26-year-old man had chief complaint of a long

lower jaw. He denied any major systemic diseases or drug

allergies.

Clinical FindingsThe clinical examination presented skeletal Class III

relationship, retrognathic maxilla, excessive lower facial

height and prognathic mandible with chin deviation to

the left 3 mm. He had non-consonant smile arch without

gummy smile. His lateral facial profile was concave with

paranasal depression, acute nasolabial angle and shallow

mentolabial fold (Figure 1).

His dental manifestat ion presented Angle’s

Classification III malocclusion with a negative overjet of

-2 mm and overbite of 2.5 mm. The upper dental midline

was 2 mm right to facial midline while the lower dental

midline was 2 mm left to facial midline. For the maxilla,

upper incisors were proclined (U1/SN=128.5°), mild

crowding and right-side up occlusal plane canting. In

contrast, the mandible presented spacing between canine

and first premolar at both side with slightly retroclined

lower incisors (L1/MP=85°) (Figure 2, Table 1).

From radiographic examination, all permanent teeth

were erupted with 24 endodontically treatment. Average

retropalatal and retroglossal and airway space, which was

9 mm and 12 mm respectively, were observed (Figure 3).

Figure 1. Pre-treatment facial photographs.

Figure 2. Pre-treatment intraoral photographs.



Treatment Goals

Soft Tissue• Correct facial proportion• Correct lip posture• Improve smile arch

Skeletal• Correct midface deficiency and mandibular prognathism• Correct maxilla canting• Correct chin deviation

Dental • Correct dental inclination and relationship • Achieve Class I canine and Class II molar relationship

Figure 3. Pre-treatment radiographs.

Treatment goals and treatment plan

From the examination, the treatment goals were set.

From the diagnosis and treatment goals together with

patient’s expectation, the treatment plan was performed

with a modified surgery-first approach as following steps.

1. General dental care: Full mouth scaling and polishing

2. Presurgical orthodontic treatment: 14, 24 extraction for

reducing incisal proclination, alignment and levelling.

3. Orthognathic surgery:

Maxilla: 2-pieces LeFort I osteotomy

Mandible: Köle procedure and BSSO for mandible

setback and asymmetry correction.

Genioplasty: chin contouring

4. Post-surgical orthodontic treatment

5. Retention


Treatment ProgressIn the maxilla, the significant maxillary crowding

was relieved by 14 and 24 extractions while partially

retracting the maxillary incisors to reduce the incisal

proclination. Then, the upper incisors inclination was

furtherly corrected more by a 2-pieces LeFort I osteotomy

and closure of the 14, 24 residual dental space during

surgery.

In the mandible, the lower dental spacing was

caused by general tooth size and jaw bone discrepancy

with relative upright incisal inclination. The presurgical

preparation included consolidation the dental space distal

to the bilateral mandibular canines. The presurgical

orthodontics preparation took 7 months before surgery.

Then, the pre-operative records were taken included

dental radiographs, cone beam computed tomography

(CBCT) and surgical models. For surgical plan, a 2-pieces

LeFort I osteotomy were performed which was cut at the

area between 13-15 and 23-25. Anterior maxilla portion

Figure 4. The surgical planning.

was clockwise rotated which resulted in upper incisor

setback 4 mm, downward 1 mm and decreasing their

inclination. The posterior portion of maxilla was moved

forward for space closure and posterior impacted for

further dental occlusion.

The bilateral sagittal split osteotomies (BSSO)

were conducted for mandible setback and asymmetry

correction. The mandible was set back 8mm at the

right side and 5mm at the left side. Additionally, the

subapical osteotomy with Köle procedure was applied

with 2mm setback at the right side and 4mm setback at

the left side. This procedure helped closing the dental

space in the mandibular arch while keeping the anterior

teeth in relative normal inclination. The excessive chin

prominence caused by the Köle procedure was reduced by

reduction genioplasty and surface contouring (Figure 4).

Post-operative orthodontic treatment took about 19

months included overbite control and detailing of the

occlusion and interdigitation.



Treatment ResultsAfter treatment, patient’s profile was improved

to straight facial profile, symmetry and good facial

proportion. All surgical segments were stable. Class I

canine relationship and Class II molar relationship were

achieved with 2 mm overjet and 2 mm overbite. The

maxillary incisors proclination were improved, all the

dental spaces were closed and well interdigitation (Figure

5, Table 1).

From the superimposition, the mandible was setback

and the maxilla was clockwise rotated by impaction of

posterior segment upward 3 mm. The pogonion point was

moved backward by 7 mm along with posterior airway

reduction to 8 mm at retropalatal and retroglossal area

(Figure 6).

This case report was approved by the Institutional

Review Board and Medical Ethics Committee of Chang

Gung Memorial Hospital (No. 201900284B0).

Figure 5. Post-treatment photographs at the time of debond (19 months after surgery).



Figure 6. 2D and 3D Superimposition of before and after treatment. InitialDebond

Table 1. The cephalometric analysis in before and after treatment.

Skeletal

Pretreatment Debond Norm

SNA 85.0 84.0 79.4 - 82.5

SNB 92.0 84.0 74.6 - 77.8

ANB 7.0 0.0 4.1 - 5.7

SND-MP 30.5 35.0 34.2 - 38.6

Dental Analysis

Upper-NA (mm) 13.0 8.5 3.8-7.2

U1/SN⁰ 128.5 114.0 103.5-109.1

L1-NB (mm) 28.0 27.0 6.1-9.5

L1/MP⁰ (Me-Go) 85.0 87.5 91.1-98.3

Facial Analysis

E-line (mm)Upper 0.5 1.0 0.8-3.2

Lower 6.0 1.0 1.2-4.4

Retropalatal Airway 12.0 8.0

Retroglossal Airway 9.0 8.0



technique alone. They generate a better result with less

effect on posterior airway space and provided good

skeletal stability.9,17

Although, upper anterior incisors showed severe

proclination, an excessive amount of rotation at anterior

segment of maxilla could not be done. The large bony

step between anterior and posterior segment should be

considered. It also could cause the periodontal problem

at distal of canine where the surgical cut and extraction

space closure take place which could lead to periodontal

problem such as gingival recession (1.5%).18

Therefore,

with the limitation above, the upper incisors still show

some proclination at the end of the treatment (U1/SN =

114⁰), but no periodontal problem was founded. The side

effect of Köle osteotomy set back is bony prominence

and excessive chin contour.19

The genioplasty could help

contouring the bony prominence and correct remaining

asymmetry.

Finally, a proper surgical result not only concern

about facial profile and dental occlusion, but also airway

space should be appropriate considered. Some maxillary

incisors proclination and minor reduction of airway space

were observed, however, patient reports no change in

sleep quality and feels pleasing with the treatment result.

CONCLUSION

The treatment goals of the dentoalveolar portion and

facial proportion should be contemplated for the staged

procedures to improve the efficiency and effectiveness of

the treatment outcome. Soft tissue including airway space

also should be carefully evaluated to avoid the unwanted

side effects and provided the most suitable treatment for

patient.

REFERENCE

1. Hardy D, Cubas Y, Orellana M. Prevalence of angle

class III malocclusion: A systematic review and meta-

DISCUSSION

With the modified surgery-first technique, the

presurgical orthodontic treatment was performed to reduce

severe incisal inclination, minor levelling and alignment

but didn’t aim for fully dental alignment, space closure

or occlusal interdigitation. Thus, this patient took only 7

months for presurgical orthodontic treatment preparation.

The 2-pieces LeFort I and Köle osteotomy then addressed

the correction in the dentoalveolar portion for efficiently

control the inclination of the anterior teeth.12

For the surgical design, the clockwise rotation of

maxilla could help reducing the incisal inclination.5

From the study of Gandedkar et al., the range of 4-8 mm

setback surgery in bimaxillary surgery showed no change

in risk factors scores for obstructive sleep apnea (OSA).15

However, for this patient, a big amount of rotation was

needed for fully correction which could affect the amount

of bone reduction and could affect the posterior airway

space.10,11

On the other hand, the discrepancy between tooth-

size and arch length in this patient resulted in large

amount of spacing in mandibular arch especially at distal

of lower canine at both sides. If the spacing would be

closed by only orthodontic movement before surgery, a

large amount of incisors retraction or molar protraction

were needed which could lengthening the presurgical

orthodontics treatment. On the contrary, if spacing were

kept for prostheses or planned for space closure after

surgery, the large amount of mandibular setback more

than 8 mm could not be avoided.

Therefore, the combination of the clockwise rotation

of maxillary anterior segment from 2-pieces LeFort I

osteotomy and Köle osteotomy combined with BSSO was

chosen to reduce incisors angulation and space closure.16

The posterior segment of maxilla was moved forward to

close extraction space and Köle osteotomy was helped to

close the excessive mandibular spacing which resulted in

less amount of total mandibular set back by just BSSO



13. Sahin T, Garreau E, Komakli Y, et al. Mandibular

anterior segmental subapical osteotomy for incisor

axis correction. J Stomatol Oral Maxillofac Surg

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14. Bell WH. Subapical osteotomy to increase mandibular

arch length. Am J Orthod 1978;74(3):276–285.

15. Gandedkar NH, Chng CK, Por YC, et al. Influence

of Bimaxillary Surgery on Pharyngeal Airway in

Class III Deformities and Effect on Sleep Apnea:

A STOP-BANG Questionnaire and Cone-Beam

Computed Tomography Study. J Oral Maxillofac Surg

2017;75(11):2411-2421.

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Modality for Skeletal Class III Malocclusion with

Labioversed Upper Incisors and/or Protrusive Maxilla.

J Craniomaxillofac Surg 2009;20(6):2049–2054.

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segmentalized Le Fort I osteotomies with miniplate

fixation in patients with maxillary hypoplasia. J Oral

Maxillofac Surg 1995;53:1407–12.

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3. Tang ELK. The Prevalence of Malocclusion Amongst

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4. Staudt CB, Kiliaridis S. Different skeletal types

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5. Worms FW, Isaacson RJ, Speidel TM. Surgical

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mandibular surgery. Angle Orthod 1976;46:1–25.

6. Pelo S, Gasparini G, Garagiola U, et al. Surgery-first

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9 . Arpornmaeklong P, Heggie AA, Shand JM.

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J Craniomaxillofac Surg 1989;17(5):219–221.

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A Modified Surgery ApproAch MAndibulAr prognAthiSM ... · detailing of the occlusion. After treatment, the maxillary incisors proclination was corrected and all the dental spaces