Unilateral spring space regainer: A smart way to drive ... spring space regainer: A smart way to...

APOS Trends in Orthodontics | September 2013 | Vol 3 | Issue 5 163

Address for correspondence: Dr. Abhishek Singha Roy, 77 Nilmoni Shome Street, Bhadrakali, P.S. Uttarpara, Hooghly - 712 232, West Bengal, India. E-mail: [email protected]

Unilateral spring space regainer: A smart way to drive molar distally

Abhishek Singha Roy, Anil Kr Chandna,

Amrita Puri

Departments of Orthodontics and Dentofacial Orthopedics,

ITS Dental College Hospital and Research Centre, Greater Noida,

Uttar Pradesh, India

AbstractEarly loss of permanent teeth due to pathological or any other iatrogenic causes precludes development of normal intra‑arch as well as interarch relationship. In recent years, non‑extraction treatment approaches using non‑compliance mechanics have become more popular in the successful resolution of space discrepancies. The following article describes an innovative spring, which is particularly suitable for unilateral space gaining with minimum side‑effects. The utility of the spring has been illustrated in a case of bimaxillary protrusion.

Key words: Distalization, space regainer, spring

INTRODUCTION

For many years, asymmetric headgear force application was used routinely for the unilateral distalization of maxillary molars.[1‑3] It has, however, been shown that such a force delivery system unavoidably contains a lateral component, which can result in a posterior cross‑bite.[4] Another serious disadvantage of headgear treatment is the need for patient compliance, which is sometimes difficult or impossible to obtain.[5] Although a myriad of appliances that do not require special patient compliance have been developed to drive maxillary molars distally, including repelling magnets, the Jones Jig (American Orthodontics, 1714 Cambridge Ave., Sheboygan, WI 53082, USA), Pendulum Appliance (Ormco/“A” Company, 1717 W. Collins Ave., Orange, CA 92867, USA), Distal Jet (American Orthodontics, 1714 Cambridge Ave., Sheboygan, WI 53082, USA) and the intraoral bodily molar distalizer,[6‑10] many of these appliances produce

unwanted tipping of the maxillary molars.[10] The pendulum appliance particularly has a tendency to create crossbites due to its pendular pattern of activation.[10] There are a few case reports but yet no conclusive evidence on the tooth movements that occur when the same appliances are used unilaterally after some modification.[11]

The present article introduces a maxillary space regaining appliance, unilateral spring space regainer (USSR), which is ideally suited for unilateral space regaining by driving the molar distally. It has the same principle as the pendulum, but as distalizing forces are applied parallel to the posterior dental arch, the pendular movement is avoided, thereby precluding palatinization of the maxillary molar.

FABRICATION AND PLACEMENT

Separators were placed on the mesial and distal contact of 1st permanent maxillary molars and contralateral canine or premolar (as the case may be) of the side where space is to be gained. The molar to be distalized is banded and a lingual sheath (0.036” × 0.072”) is welded to the band. Contralateral canine or premolar was then banded. Impression was taken in polyvinyl siloxane for optimal accuracy. Impression, along with bands was washed and disinfected with 2% glutaraldehyde and poured with

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APOS Trends in Orthodontics | September 2013 | Vol 3 | Issue 5

Roy, et al.: Unilateral spring space regainer

164

dental stone for fabrication of a working cast.

On the working model, we adapted two 0.036” stainless steel wires in a curved configuration and soldered

them to the bands of the molar and opposite canine or premolar. A spring was then fabricated with 0.032 Titanium Molybdenum Alloy (Ormco/“A” Company, 1717 W. Collins Ave., Orange, CA 92867, USA) at length 10 mm [Figure 1] and one end of the wire was then bent in such a way that it can be tucked inside the lingual sheath. The spring was then positioned in the model at a level 5‑6 mm apical to the center of resistance of the molar [Figure 2]. The Nance button was fabricated using self‑cure acrylic, covering a large portion of the palate, but leaving the body of the spring uncovered to allow activation [Figure 3]. The modified Nance button with the embedded spring was then removed from the cast finished and polished [Figure 4]. To activate the USSR, the spring should be opened 3‑4 mm outside the mouth (which will produce around 150 g force) and then inserted in the palatal sheath. This spring can result in pure translation of the molar distally without any bucco‑lingual rotation if force is applied from both

Figure 1: Fabrication of titanium molybdenum alloy spring Figure 2: Spring adapted on the model with one end tucked inside the palatal sheath

Figure 3: Modified Nance palatal button incorporating titanium molybdenum alloy spring Figure 4: Finished unilateral spring space regainer

Figure 5: Biomechanics of the appliance






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buccal and palatal aspects. So a nickel‑titanium (NiTi) open coli spring (0.010” × 0.030”), compressed 10 mm to its resting length (generate 100 g of force) should be ligated on the buccal aspect of the molar to counteract rotational moment in sagital as well as transverse plane. Palatally clockwise moment generated by applying force gingival to the center of resistance is being negated by counter clockwise moment resulting from applying force occlusal to the center of resistance on buccal side. Similarly in the transverse plane also both moments nullify each other resulting in bodily distalization of the molar without any rotation [Figure 5].

CASE REPORT

A 19‑year‑old female patient presented with the chief complaint of forward placement of the upper and lower front teeth. History revealed that patient had undergone orthodontic treatment 7 years before for high buccally placed right maxillary canine. Her right maxillary first premolar had been extracted that time to align the blocked out canine with eventual space loss by mesialization of upper permanent right first molar [Figure 6a‑c].

Clinical examination of the patient suggested bimaxillary proclination with an extracted right maxillary first premolar. To correct the proclination of anterior teeth it was then decided to extract the first premolar from the rest of three quadrants and regain space by distalizing the first molar in the right quadrant. Upper right third molar was extracted to facilitate distalization. USSR was activated by 4 mm [Figure 7a] and then cemented [Figure 7b]. NiTi open coil spring (0.010” × 0.030”) was placed on the buccal aspect between the right canine and first molar after compressing it by 10 mm. After 2 months, the maxillary right first molar was distalized by 4 mm. At the end of 3½ months, distalization was completed and 7 mm space was gained in the right maxillary quadrant [Figure 8a and b]. Orthopantomogram of the patient demonstrated near complete translatory movement of the maxillary right first molar [Figure 9a and b].

Figure 6: Pretreatment study models

Figure 7: (a) Unilateral spring space regainer: Passive. (b) Unilateral spring space regainer: Active

ba

Figure 8: (a) After completion of space regaining: Occlusal aspect. (b) After completion of space regaining: Buccal aspect

ba

Figure 9: (a) Panoramic radiograph: Pre‑treatment. (b) Panoramic radiograph: After completion

b

a






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Ensuring adequate stabilization of the distalized molar for a period of 6 months anterior retraction was started. At present, (after 11 months) the case is in space closure stage [Figure 10a‑c].

CONCLUSION

Advantages of USSR include• Easy to fabricate• Economic• It produces constant and parallel forces• It produces forces near 200 g and distalizes at a rate

of 2 mm/month• Three dimensional‑molar control• Bodily molar movement with little or no tipping• Proven to be effective even in the presence of fully

erupted second molar• Minimal requirement of patient cooperation• Excellent distalization appliance for patients with

deep bite and hypodivergent growth pattern.

Limitations of USSR includes• We must invest laboratory time to make this

appliance• Activation is difficult• The acrylic anchorage plate retains food particles• Strict control of the appointments.

REFERENCES

1. Haack DC, Weinstein S. The mechanics of centric and eccentric cervical traction. Am J Orthod 1958;44:236‑57.

2. Baldini G. Unilateral headgear: Lateral forces as unavoidable side effects. Am J Orthod 1980;77:333‑40.

3. Wohl TS, Bamonte E, Pearson HE. Nonextraction treatment of unilateral Class II, Division 1 malocclusion with asymmetric headgear. Am J Orthod Dentofacial Orthop 1998;113:483‑7.

4. Yoshida N, Jost‑Brinkmann PG, Miethke RR, König M, Yamada Y. An experimental evaluation of effects and side effects of asymmetric face‑bows in the light of in vivo measurements of initial tooth movements. Am J Orthod Dentofacial Orthop 1998;113:558‑66.

5. Clemmer EJ, Hayes EW. Patient cooperation in wearing orthodontic headgear. Am J Orthod 1979;75:517‑24.

6. Gianelly AA, Vaitas AS, Thomas WM, Berger DG. Distalization of molars with repelling magnets. J Clin Orthod 1988;22:40‑4.

7. Jones RD, White JM. Rapid Class II molar correction with an open‑coil jig. J Clin Orthod 1992;26:661‑4.

8. Hilgers JJ. The pendulum appliance for Class II non‑compliance therapy. J Clin Orthod 1992;26:706‑14.

9. Carano A, Testa M. The distal jet for upper molar distalization. J Clin Orthod 1996;30:374‑80.

10. Keles A, Sayinsu K. A new approach in maxillary molar distalization: Intraoral bodily molar distalizer. Am J Orthod Dentofacial Orthop 2000;117:39‑48.

11. Reiner TJ. Modified Nance appliance for unilateral molar distalization. J Clin Orthod 1992;26:402‑4.

How to cite this article: Roy AS, Chandna AK, Puri A. Unilateral spring space regainer: A smart way to drive molar distally. APOS Trends Orthod 2013;3:163-6.

Source of Support: Nil. Conflict of Interest: None declared.

Figure 10: After 11 months of treatment




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