Nonextraction Correction of Class II Malocclusion by Pendulum Appliance.

A 13-year-old female patient, presented with the chief complaint of forwardly placed upper front teeth. On examination and analysis of relevant records, she was diagnosed as an Angle's Class II malocclusion on a skeletal Class I base. It was decided to treat the patient with a nonextraction treatment approach with the help of maxillary molar distalization followed by fixed mechanotherapy. Copyright:

INTRODUCTION

Since the early 1980s various intra arch Molar Distalizing systems have been developed that aimed to minimize the reliance on the patient compliance.[1] Pendulum appliance being important part of this intraarch system is simple and efficient. It was introduced by HILGERS in 1992.[2] Since then, many variations have emerged and their clinical application has had great success.[3]

The distalization mechanism consists of bilateral helical spring made out of titanium molybdenum alloy. Unlike Jones jig, it does not have any coil springs; instead, it has 0.032 inches TMA springs which deliver a continuous force against the maxillary first molar producing 200 to 250 gms of force in a swimming arc movement from the midline, hence the name pendulum.[4]

CASE REPORT

Section I: Pretreatment assessment

History and clinical examination

A 13 year old female patient, presented with the chief complaint of forwardly placed upper front teeth.

Extraoral examination [Figure 1] revealed a Europrosopic facial form with convex profile, and low mandibular plane angle. The nasolabial angle was acute, and mentolabial sulcus was deep and potentially incompetent lips. The intraoral examination revealed [Figure 2] that patient exhibited Angle's Class II molar relationship and a Class II Division 1 incisor relationship with 10mm of overjet and 6mm overbite.

Figure 1

Extraoral pretreatment

Figure 2

Intraoral pretreatment

General radiographic examination

Panoramic radiographic examination [Figure 3], revealed the presence of all the permanent teeth and developing tooth germs of all the third molars except the mandibular left third molar. Cephalometric evaluation[5] [Figure 4 and Table 1] revealed skeletal Class I jaw bases, horizontal growth pattern, decreased lower anterior facial height, increased overjet and overbite, convex profile, proclination of the maxillary incisors, average lower incisors and acute nasolabial angle.

Figure 3

Panoramic radiograph pretreatment

Figure 4

Lateral cephalogram pretreatment

Table 1

Pre- and post- treatment cephalometric values

Variables	Pretreatment	Posttreatment
Sagittal skeletal relationship
SNA (°)	79	78
SNB (°)	77	77
ANB (°)	2	1
Wits appraisal	1	0.5
Dental base relationship
Upper incisor to NA (mm/°)	9/42	4.5/25
Upper incisor to NB (mm/°)	2.5/22	4/25
Upper incisor to SN plane (°)	122	103
Lower incisor to mandibular plane (°)	102	97
Dental relationship
Interincisal angle (°)	115	128
Lower incisor to APog line (mm)	0	2
Overbite (mm)	6	3
Overjet (mm)	10	2.5
Vertical skeletal relationship
SN plane to mandibular plane (°)	24	25
Y- axis	56	56
Soft tissue
Lower lip to Ricketts E plane (mm)	0	1

SN: Sella - Nasion, SNA: SN - A point, SNB: SN- B point, ANB: A point - Nasion - B point, NA: Nasion- Point A, NB: Nasion- Point B

Model analysis

Model analysis revealed 8 mm spacing in maxillary arch and 4.2 mm spacing in mandibular arch. Bolton analysis showed total maxillary tooth material excess and an anterior mandibular excess.

Diagnosis

The 13-year old growing female patient with Angle's Class II malocclusion on a skeletal Class I base with horizontal growth pattern, spacing in maxillary arch, proclination of maxillary incisors, average mandibular incisors, increased overjet and overbite, deep curve of Spee, with mandibular midline shifted to the right, convex profile, and acute nasolabial angle with decreased lower anterior facial height.

Treatment objectives

To establish bilateral Class I buccal segment relationship, ideal overjet and overbite.

To correct dental midlines, upper incisor Proclination, convex profile and normalize the acute nasolabial angle and achieve soft tissue balance and harmony.

Treatment plan

Appliance: Hilgers pendulum appliance followed by fixed mechanotherapy.

Special anchorage requirement: pendulum appliance and transpalatal arch.

Proposed retention strategy: Fixed lingual bonded retainers for the lower anteriors and the upper incisors and upper Hawley's retainer.

Section II: Treatment

After the fabrication of the appliance, it was cemented with the desired activation [Figure 5]. Molar distalization phase continued for 7 months. During the end stages of molar distalization, the anchorage taken from the second premolars was relieved to facilitate their distal movement [Figure 6]. After the pendulum appliance was removed, transpalatal arch was given on the same day.[3] Fixed mechanotherapy was started with MBT prescription 0.018′′ slot. After the initial alignment of maxillary teeth, 0.016′′ special plus Australian archwire was given, with E-chains to retract the maxillary premolars followed by maxillary canines [Figure 7]. Incisor retraction was done using closing loop fabricated in 0.016''* 0.022'' SS wire. [Figure 8]. In the mandibular arch, utility arch was given fabricated using 0.016'' * 0.016'' SS wire for incisor intrusion [Figure 9]. Space closure in both the arches was done. Upper and lower 0.017′′×0.025′′ NiTi archwires were given followed by 0.017′′×0.025′′ SS arch wires for finishing [Figure 10]. Subsequently 0.016′′ NiTi archwires were given along with elastics for the appropriate occlusal settling. Active treatment lasted for 1 years and 9 months after which fixed appliance was removed.

Figure 5

Pendulum appliance

Figure 6

Second premolars relieved

Figure 7

Individual canine retraction

Figure 8

Incisor retraction

Figure 9

Mandibular utility arch

Figure 10

Finishing stage completed

Interpretation of posttreatment cephalometric values

Posttreatment panoramic radiograph [Figure 13] showed root parallelism. Lateral cephalogram [Figure 14] showed both normal overjet and overbite. Cephalometric Superimposition summarizes the outcome of the treatment [Figure 15]. Soft tissue profile improved drastically due to the correction of the maxillary incisor proclination and increase in lower anterior facial height. Occlusal Indices [Table 2] showed satisfactory results.

Figure 13

Panoramic radiograph posttreatment

Figure 14

Lateral cephalogram posttreatment

Figure 15

Superimposition

Table 2

Cephalometric analysis for sagittal changes

Variables	Pre	Post
Lower facial height angle (°)	35°	38°
i-CEJ/PTV (mm)	45	41
m1- CEJ/PTV (mm)	20	19.5
m2- CEJ/PTV (mm)	10.5	10
m1- CEJ/ANS- PNS (mm)	12	12
i/ANS-PNS (°)	125	110
i/SN (°)	121	103
m1/ANS-PNS (°)	78	77
m2/ANS-PNSMI/SN (°)	68	66
m1/SN (°)	76	76
m1/SN (°)	63	63

SN: Sella - Nasion, ANS: Anterior nasal spine, PNS: Posterior nasal spine, CEJ: Cementoenamel junction, PTV:Pterygoid Vertical, PNSMI: Posterior nasal spine – Maxillary Incisor

Critical appraisal

The posttreatment results achieved were highly satisfactory with good posterior occlusion [Figure 11] and excellent facial soft tissue balance and harmony [Figure 12]. The patient and parents were highly satisfied with the treatment result.

Figure 11

Postdebonding Intraoral photographs

Figure 12

Postdebonding extraoral photographs

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.