Case Report: Correction of Class II Div 2 Malocclusion With Maxillary Arch Extraction and Lower IPR

Abstract

Abstract

This case was submitted to the board under category IV for the Indian Board of Orthodontics examination, November 2013. The summary of the treatment, records, and treatment progress are reprinted with minimal editing and reformatting so that the manuscript resembles the actual documents submitted to the board.

Introduction

PL, an 18-year-old male, presented with class II div 2 incisor relationships with high and buccally placed upper canines and end-on molar on a class II skeletal base. He had severe deep bite and reduced overjet with severe crowding in upper and lower arches. Lips were incompetent with gumminess on smiling.

Treatment involved extraction of upper first premolars and nonextraction in lower arch with interproximal reduction in the incisor region. Appliance used is preadjusted edgewise with 18 × 25 slot and MBT prescription.

Section 1. Pretreatment Assessment

Patient details

Initials: P. L.

Sex: Male

Date of birth: November 3, 1991

Age at start of treatment: 18 years 5 months

Patients complaints: Irregularly placed front teeth

Relevant medical history: Nil relevant

Clinical examination: Extraoral Features (Figure 1)

• Average toward horizontal mandibular plane angle

• Skeletal class II pattern with convex profile and prominent chin

• Acceptable facial symmetry and balance on frontal examination

• Upper dental midline shifted toward left by a 1 mm in relation to facial midline.

• Incompetent lips

• Normal nasolabial angle

• High lip line

• No sign and symptoms of temporomandibular disorder

Figure 1.

Pretreatment Photographs (Extraoral)

Figure 2.

Pretreatment Photographs: Intraoral

Clinical Examination: Intra-Oral Features (Figure 2)

• Soft tissues: Moderate gingivitis

• Oral hygiene: Poor oral hygiene

• Erupted teeth present: Central incisor to second molars in all quadrants

• General dental condition: Attrition of Incisal edges of LR1 and LL1

Crowding/Spacing

Maxillary Arch:

Contracted arch form

Severe labial segment crowding

Deep palate

High placed upper canines

UR1, UL1, UL2: Retroclined, UR2: Proclined

Mandibular Arch:

Tapered arch form

Severe labial segment crowding

Occlusal Features:

• Incisor relationship: Class II div 2

• Overjet (mm): 0 mm

• Overbite: Complete coverage of lower incisors (90%)

• Centrelines: Upper and lower coincident and toward left by 1 mm in relation to facial midline

• Left buccal segment relationship: Molars: class II, Canines: class II

• Right buccal segment relationship: Molars: class II (End-on), Canines: class II

• Crossbites: None, Displacements: None

• Other occlusal features: Deep curve of spee

General radiographic examination (Figure 3)

Pretreatment radiographs taken: Orthopantomogram (17/4/10)

Lateral Cephalogram (17/4/10)

Unerupted teeth: 8 8

Other relevant radiographic findings:

Space for erupting third molar seems to be deficient

Roots of upper and lower incisors mesially angulated indicating lack of space for proper

Alignment

Diffuse calcification present between roots of lower right first and second premolars.

Figure 3.

Pretreatment Radiographs

Other Special Tests/Analyses

Bolton’s Analysis:

The mesiodistal widths of the maxillary and mandibular teeth were ascertained using spring dividers. The mesiodistal widths of the maxillary and mandibular teeth are as under:

Sum of maxillary 12 teeth (6-6) = 101

Sum of mandibular 12 teeth (6-6) = 94.5

Sum of maxillary 6 teeth (3-3) = 50

Sum of mandibular 6 teeth (3-3) = 41

Overall Bolton Ratio = 94.5/101 × 100 = 93.56 % (Mean 91.3, SD 1.91) (> 91.3%).

This value reveals that there is an overall mandibular excess, calculated in mm as follows:

Overall Mandibular excess (in mm) = Sum of mandibular 12 – Sum of maxillary 12/100 × 91.3

= 94.5 – 101/100 × 91.3

= 2.287 mm

Anterior Bolton ratio = 41/50 × 100 = 82% (Mean 77.2, SD 1.65)

(> 77.2%) This value reveals that there is an anterior mandibular excess, calculated in mm as follows:

Anterior mandibular excess (in mm) = Sum of mandibular 6 – Sum of maxillary 6/100 × 77.2

= 41 – 50/100 × 77.2

= 2.4 mm

Inference

The ratio was outside one standard deviation of the mean overall and anterior ratio suggesting a tooth size discrepancy. In this instance the discrepancy was considered to be largely due to overall mandibular dental excess.

Radiographic Interpretation

Following are the radiographic interpretation (refer to Table 1):

Skeletal: The cephalometric analysis revealed a class II skeletal anteroposterior relationship with an ANB of 5.5° and wits of +4 mm. The SNB angle of 73° suggests that the mandibular retrusion is more responsible for the sagittal skeletal disharmony.

Vertical proportions indicate to a horizontal growth pattern as suggested by GoGn to SN, MM angle and Jarabak ratio.

Dental: The upper incisors are severely retroclined as suggested by cephalometric values (upper incisor to NA plane 4° and –2 mm and SN plane 82.5°). Lower incisors are upright over the basal bone (lower incisor to NB 18.5° and +3 mm and incisor to mandibular plane angle [IMPA] 97°). Incisal edge is placed behind the A-Pog line (–2 mm). Inter incisal angle is 152°.

Soft tissue: Nasolabial angle is 97.5°. Lower lip is retrusive in relation to the Ricketts E plane –3 mm.

Table 1.

Pretreatment Cephalometric Analysis

Variables	Values
SNA	78.5°
SNB	73°
ANB	5.5°
Wits appraisal	+4mm–
Upper incisor to NA (mm/deg)	2 mm/4°
Lower incisor to NB (mm/deg)	+3 mm/18.5°
Upper incisor to SN plane	82.5°
Lower incisor to mandibular plane angle (IMPA)	97°
Interincisal angle	152°–
Lower incisor to APo line	2 mm
Over bite	8 mm
Overjet	0 mm
Maxillary–mandibular planes angle	19°
SN plane–mand plane	27°
Upper anterior face height	54 mm
Lower anterior face height	65 mm
Face height ratio	54.62%
Jarabak ratio	70.83%
Maxillary length	97mm
Mandibular length – effective (McNamara)	120 mm

Diagnostic Summary

PL an 18-year-old male presented with a class II div 2 incisors and angles class II molar relationship on a class II skeletal base with normal or mildly reduced vertical height. There was a severe crowding in upper and lower arches with increased overbite and decreased overjet. Canines were high and buccally placed. Lips are incompetent and upper midline is shifted toward left by 1 mm.

Problem List

1. Class II skeletal jaw relationship

2. Deep bite

3. Severe crowding in upper and lower arches

4. High placed canines

5. Deep curve of spee in lower arch

6. Reverse curve of spee in upper arch

7. Incompetent lips

8. Gummy smile

9. Centerline discrepancy

Aims and Objectives of Treatment

1. To achieve functionally optimum and aesthetically acceptable occlusion

2. Accept the skeletal class II pattern

3. Relief of crowding

4. Correction of deep bite and reduced overjet

5. Level, align, and coordinate the dental arches

6. Correction of gummy smile

7. Correction of centerline discrepancy

8. Competency of lips

9. Achieving class II molar, class I canine, and incisor relationship

10. Retain corrected results

11. Evaluate for third molar extraction

Treatment Plan

The treatment was aimed mainly at dental correction of skeletal problem. Space needed to relieve crowding in the upper arch is resolved by extraction of first premolars. Extraction/Nonextraction in the lower arch is to be planned after alignment of upper arch, correction of deep bite, and overjet. In case of nonextraction, interproximal reduction is to be planned for space requirement in lower arch during the course of treatment. Bolton’s tooth size analysis shows mandibular anterior excess by 2.4 mm.

Extractions: upper first premolars

Appliances: PEA with MBT prescription 018 × 025 slot

Special anchorage requirements: None

Minor adjunctive surgery: None

Major adjunctive surgery: None

Additional dental treatment: None

Proposed Retention Strategy

Lingual bonded retainer in upper and lower arches to be given. Hawleys retainer to be worn full time along with fixed retainer for a period of 6 months followed by night wear for next 6 months.

Prognosis for Stability

Provided the lower incisors were not proclined excessively from the original position, good archform maintained, and good occlusal interdigitation was achieved the long-term stability of treatment changes was considered good.

Being a dental camouflage of a skeletal problem, the lower incisors will get proclined to correct overjet. To maintain their position, permanent retention is desirable. Maintenance of corrected deep bite will need mild anterior bite plane in upper Hawley’s for long-term stability of results.

Section 2. Treatment

Treatment progress (Table 2)

Start of active treatment: 17 April 2010

Age at start of active treatment: 18 years 5 months

End of active treatment: 15 June 2013

Active treatment time: 3 years 2 months

End of retention: Ongoing Figure 4.

Midtreatment Photographs

Table 2.

Key Stages in Treatment

Date	Stage
1. April 2010:	Records taken. Extraction of upper first premolars done under local anesthesia.
2. May 2010:	Banding and bonding done in upper arch. 018 × 025 slot with MBT prescription used. 014 NiTi given. UL3 left out of arch wire. Direct ligation done UL6-UL3.
3. September 10:	Alignment of incisors achieved. NiTi with mild activation engaged to UL3 with the help of ligature wire. Canine pulled distally as well as incisally.
4. March 11:	Alignment achieved. Individual ligation done in all teeth.
5. May 11:	Wire changed to 16 × 22 NiTi in upper arch.
6. July 11:	Bonding done in lower with a temporary attachment on LL2. 014 NiTi given in lower arch (Figure 4). Upper wire changed to 016 SS AJ Wilcock with curve of spee to intrude upper anteriors. Elastomeric chain given to close the spaces between UR3 to UR2. Coil spring given between UR6 and UR5 to mesialize second premolar.
7. January 12:	16 × 22 NiTi in lower and 17 × 25 NiTi in the upper arch.
8. March 12:	17 ×25 SS omega loop given for protraction of UR 6 and close the spaces between upper right first molar and second premolar. Lower 016ss (A J Wilcock) with reverse curve of spee given for correcting the deep curve of spee. Interproximal stripping done to correct the interproximal contact, bunching of the roots. Distoinciasally angulated crown of LR2 and LL2.
9. September 12:	17 × 25 NiTi given in upper arch and 16 × 22 NiTi given in lower arch. Bracket position of LR 2 changed for correction of crown and root angulation.
10. November 12:	17 × 25 in NiTi lower arch and 17 × 25 SS in upper arch
11. March 13:	Palatal root torque added for upper incisors and labial root torque for LR2 and LL2. 17 × 25 SS in upper and lower arch
12. June 13:	Lingual bonded retainer, debonding done, and records taken.

Section 3. Post treatment Assessment

Occlusal features (Figures 5 and 6)

Incisor relationship: Class I

Overjet (mm): 2 mm

Overbite: 2 mm

Centerlines: Coinciding with each other and with facial midline

Left buccal segment relationship: Molar, class II

Canine: Class I

Right buccal segment relationship: Molar, class II

Canine: Class I

Crossbites: None

Displacements: None

Functional occlusal features: Mutually protected occlusion with canine guidance on excursive movements

Figure 5.

Posttreatment Photographs: Extraoral

Complications Encountered During Treatment

The patient had difficulty in maintaining a good standard of oral hygiene. Poor oral hygiene led to black triangles at interdental pappilae in the lower incisor region. Had to reduce interproximally to establish good contact and correct black triangle. Treatment of lower arch without extraction made alignment little difficult. Torqueing and up righting of LL 2 and LR 2 roots took a lot of time.

Figure 6.

Posttreatment Photographs: Intraoral

Figure 7.

Posttreatment Radiographs

Radiographs Taken Toward/at the End of Treatment

Radiographs taken: Lateral Cephalogram & OPG (Figure 7)

Relevant Findings

No pathology seen.

No change in root length of incisors.

Good parallelism of roots achieved.

Lack of space for eruption of lower third molars.

UR3 and UR5 roots are closer to each other and UR3 more distally inclined.

Figure 8.

Super Imposition of Pre- and Postlateral Cephalograms (A) Maxillary Changes and Mandibular Changes. (B) Overall Skeletal and Dental Changes.

Interpretation of Cephalometric Changes (Figure 8)

• Skeletal: There is a mild change in ANB value. It has reduced by 1° from 5° to 4°. May be attributed to dentoalveolar changes that taken place. SNA has increased by 1° to 79° and SNB has increased by 2° to 75°. The M-M angle has opened up by 3 from 19 to 22. Other skeletal values have remained more or less close to normal.

• Dental: Significant changes in upper incisor angulation have taken place. The upper incisor has Proclined to close to normal value from an upright position. upper incisor in relation to NA has changed from 4° and –2 mm to 26° and 3 mm. in relation to SN plane it has changed from 82.5 to 105.5 but the lower incisor has proclined significantly in relation to NB from 18.5 and +3 mm to 32 and 8 mm. IMPA has increased from 97 to 108. In relation to A-Pog plane it has changed from –2 mm to +2.5 mm.

• Soft tissue: Competence of lips achieved. Nasolabial angle has decreased by 2.5 from 97.5 to 95 attributed to change in position of upper incisor position. Lower lip in relation to rickets E plane is placed –2.5 mm, indicating a normal positioning.

Table 3

. Cephalometric Comparison

Parameters	Pretreatment	Posttreatment
SNA	78.5°	79°
SNB	73°	75°
ANB	5.5°	4°
Wits appraisal	+4 mm	+5 mm
Upper incisor to NA (mm/deg)	−2 mm/4°1	3 mm/26°
Lower incisor to NB (mm/deg)	3 mm/18.5°	8 mm/32°
Upper incisor to SN plane	82.5°	105°
Lower incisor to mandibular plane angle (IMPA)	97°	108°
Interincisal angle	152°	117°
Lower incisor to APo line	−2 mm	+2.5 mm
Over bite	8 mm	2 mm
Overjet	0 mm	2 mm
Maxillary−mandibular planes angle	19°	22°
SN plane−mand plane	27°	27°
Upper anterior face height	54	55
Lower anterior face height	65	69
Face height ratio	45.3:54.6	44.3:55.6
Jarabak ratio	70.83%	70.63%
Maxillary length	97 mm	96 mm
Mandibular length − effective (McNamara)	120 mm	122 mm
Lower lip to rickets E plane	−3 mm	−2.5 mm
Nasolabial angle	97.5°1	95°

Section 4. Critical Appraisal

PL was successfully treated by orthodontic camouflage over a period of 38 months. The original treatment aims were accomplished and the patient’s chief complaint addressed. PL was notably pleased with the treatment outcome. A good occlusal and aesthetic result was achieved.

Skeletal: The anteroposterior skeletal pattern improved during treatment from moderate to mild class II relationship. This may be due to dentoalveolar remodeling. The vertical proportions have been maintained.

Dental: The severe crowding in the upper and lower arches is successfully relieved. The incisor angulations corrected to allow good aesthetics and proper function. Significant amount of bite opening has been achieved with a combination of anterior intrusion and little posterior extrusion. Good overjet and overbite have been achieved. High placed canines have been brought nicely into the occlusion without loss of gingival attachment. Well-settled class II molar and class I canine relationship has been achieved. Midlines are coincident. Interproximal stripping done in lower incisors will bring more anteroposterior stability in lower labial segment as lower incisors have been proclined significantly.

Canine root torque in upper arch is different on the right and left sides. More palatal root torque was needed in UL3. Tip on the UL3 is also more compared to the right side.

UL6 is relatively more mesiopalatally rotated in comparison to UR6. Lower incisors are significantly proclined. Increased labial root torque in LR2 and LL2 was needed.

Soft tissue: A notable change in the lip line was achieved with normal show of incisors at rest. While smiling there is less show of gingiva with improvement in gumminess. Lip competency has been achieved.

Iatrogenic

Poor oral hygiene has led to loss of gingival height interdentally leading to black triangles in lower anteriors.

No change in root length was observed in upper and lower incisors.