Case Class II correction by maxillary molar distalization with pendulum appliance - A case report

24 year male patient presented with skeletal class II base with prognathic maxilla and orthognathic mandible. Angles class II division 1 subdivision malocclusion with proclined upper and lower anteriors, increase overjet, increased overbite, spacing with upper and lower anteriors, scissor bite with 35, class I molar and canine relation on right side, end on molar and canine relation on left side. Distalization was planned in maxillary arch to correct end on molar relation on left side and upper incisor proclination. Unilateral Pendulum appliance was used to distalize upper left molar. Post treatment Class I molar relationship was achieved bilaterally within 2-4 months with incisor proclination reduced. The total treatment ended in 18 months.


Introduction
Class II malocclusion is one of the most frequent malocclusion encountered in orthodontics where distalization is considered as one of the conservative ways of treatment. 1 Maxillary molar distalization has been used successfully for more than 100 years in orthodontics to treat cases with class II malocclusion. This technique is used to relieve crowding and reduce the increased overjet by utilization of space gained. 2 The primary advantage in this technique is the ability to gain space in a conservative way without the need for extraction. A myriad of devices have been developed over the years to distalize the maxillary molars with agreeable clinical outcomes. Of various distalization appliances Pendulum Appliance introduced by Hilgers in 1992 3 emerged and the clinical application of the pendulum appliance has demonstrated good result.

Case Report
24-year male presented with the chief complaint of proclined upper front teeth with no relevant medical and dental history. On clinical examination no abnormality was detected with temporomandibular joint. Facial form was mesoprosopic and mild convex soft tissue profile incompetent lips, reduced nasolabial angle, deep mentolabial sulcus, non-consonant smile. On intraoral examination patient had end on molar and canine relation on left side, class I molar and canine relation on right side with mild proclination of upper and lower anteriors, increase overjet, increased overbite, spacing with upper and lower anteriors, scissor bite with 35 ( Figure 1). Cephalometric analysis revealed that patient had skeletal Class II base with prognathic maxilla and orthognathic mandible with average growth pattern (Table 1).

Treatment Objectives
Treatment objectives were to correct proclined upper and lower anteriors, spacing with upper and lower anteriors, increase overjet overbite, scissor bite with 35, end on molar and canine relation on left side, convex profile, and incompetent lips.

Treatment Plan
Unilateral distalization of the maxillary molars was planned using Pendulum Appliance with respect to upper left quadrant, followed by fixed appliance therapy.

Treatment Progress
Maxillary 1 st premolars, 1 st molar and 2 nd molars both right and left sides were banded and Pendulum Appliance with 0.032 TMA wire was fabricated and attached ( Figure 2). The appliance was activated by 90°to deliver a force of 220 grams. After the desired distalization was achieved in 2-4 months, appliance was kept in place for 2 months to retain the distalization effect, followed by placement of Nance palatal arch. Fixed mechano therapy by bonding with 0.018 MBT was initiated. Alignment and levelling in the both arches was carried out by following wire sequence: (a) 0.016˝heat activated nickel-titanium arch wires (b) 0.016x0.022˝nickel-titanium arch wires (c) 0.016x0.022˝SS arch wires (d) 0.017×0.025˝NiTi arch wires (e) 0.017×0.025˝SS arch wires. The arch wires were cinched distal to molar to avoid maxillary and mandibular incisor proclination. Treatment was completed in 18 months. After debonding patient was given essix retainer and follow up was done for next 6 months.

Treatment Result
Post treatment a good occlusion was achieved with bilateral Class I molar and canine relation along with normal overjet and overbite, with no spacing, no crowding in upper and lower arch and coinciding upper and lower dental and facial midlines, consonant smile and lip seal (Figure 3)

Discussion
In most of the non-extraction borderline case molar distalization procedures has been the choice of management. Unilateral Class II molar was successfully treated with Pendulum appliance. Unilateral distalization had the advantage of stronger anchorage because the contralateral side was utilized as an anchorage unit. The pendulum appliance is the preference of choice because of its simple fabrication and ease of use. To prevent side effects on the premolar and incisor regions from the pendulum springs, many modifications have been made to yield optimal clinical results. 4 In the sagittal plane, molar distalization occurred at the expense of the mild proclination of the maxillary anterior teeth due to reciprocal mesial force, thus causing anchorage loss. 5 Side effects on distalized molars are the mesial rotation caused by palatal force application and the extrusion that are similar but less than with double distalization. 6 Influence of second molar on the distal movement of the first molar remains a matter of debate. Some authors reported that presence of second molars increases treatment duration, produces more tipping of molars, 7 and more anterior anchorage loss. 8

Conclusion
For attainment of molar distalization Pendulum appliance was found to be efficient, non-invasive and non-compliant appliance where 4 mm of distalization was achieved in 4 months and occlusion was settled with class I molar and class I canine relation.

Conflicts of Interest
All contributing authors declare no conflicts of interest.

Source of Funding
None.