International Journal of Orthodontics

International Journal of Orthodontics A Simple mini-screw assembly for simultaneous molar uprighting and distalization - A case of Adjunctive Adult Orthodontics --Manuscript Draft-Manuscript Number:

IAORTHO-D-11165R1

Full Title:

A Simple mini-screw assembly for simultaneous molar uprighting and distalization - A case of Adjunctive Adult Orthodontics

Short Title: Article Type:

Clinical Article

Keywords:

Temporary anchorage devices (TADs); Distalization; Adjunctive orthodontics

Corresponding Author:

Vijay Reddy, MDS Sri Sai College Of Dental Surgery Hyderabad, Andhra Pradesh INDIA

Corresponding Author Secondary Information: Corresponding Author's Institution:

Sri Sai College Of Dental Surgery

Corresponding Author's Secondary Institution: First Author:

Vijay Reddy, MDS

First Author Secondary Information: Order of Authors:

Vijay Reddy, MDS Renu Parmar, MDS Irfan Abdul Razak Jamadar, MDS Rajesh Reddy, MDS, MOrth Deepti Reddy, MDS

Order of Authors Secondary Information: Abstract:

Anchorage is a major concern in adult mutilated dentition. However, with the explosive development of Temporary Anchorage Devices (TADs) newer avenues in orthodontic treatment philosophy have opened up. Mini-screws are found to be stable during such treatments, demonstrating that they could provide absolute anchorage for tooth movement. The present article describes a simple, yet effective technique for simultaneous molar uprighting and distalization, using direct skeletal anchorage using a mini-screw supported assembly in a 38 years old male patient as part of adjunctive adult orthodontics with mutilated dentition.

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Manuscript text

Early loss of permanent first molar without a prosthetic replacement is not an uncommon finding in a majority of adult patients. Tooth migration after extraction of the permanent first molar results in forward movement, mesial tilting and often unwanted extrusion of the teeth (including the teeth in the opposite arch) which subsequently can lead to an alteration of the plane of occlusion, resulting in potential cuspal interferences leading to collapse of occlusion and periodontal deformities.1-2 In a handful of cases this can even be a potential cause of temporomandibular joint disorders. Accordingly, orthodontic repositioning of teeth becomes a functional and biologic requisite, which in turn allows proper occlusal load distribution and prospectively assures the longevity of the prosthesis and the dentition. With prosthetic single tooth implants becoming more popular, orthodontists today see more patients requiring minimal adjunctive orthodontic intervention. These patients often require orthodontics as an adjunct to their larger needs of prosthetic replacement for functional rehabilitation. "Minimal" treatment has been recommended in this small group of adults as a part of adjunctive orthodontic treatment, primarily to control anchorage and to minimize patient discomfort. The classic treatment principle in adjunctive orthodontics is to improve a particular aspect of the occlusion rather than to comprehensively alter it. 3-4 Numerous approaches have been proposed for distalization and uprighting of mesially tipped 5-11

second molars.

Most of these methods have had problems with molar extrusion and movement

of the anchorage unit, making it necessary to apply interarch stabilization to minimize the side effects.

However, the most definite way to obtain absolute anchorage without any undue side effects as mentioned earlier is with the help of TADs (Temporary anchorage devices). The range of tooth movement has been extended impressively with the profound usage of TADs. The explosive development of TADs has opened newer avenues in orthodontic treatment philosophy, especially among adult patients often presenting with problems of anchorage due to mutilated dentition and

additional periodontal concerns. Several authors have reported retraction of the upper anterior teeth against micro-implants and simultaneous uprighting of the lower molars.12-14 The miniscrews were found to be stable during such treatment, demonstrating that they could provide absolute anchorage for tooth movement.

The present article describes a simple and effective method for simultaneous molar uprighting and distalization, using direct skeletal anchorage, which can be applied in either arch.

Case A 38 years old male patient consulted the prosthodontic clinic seeking prosthetic restoration of missing 16 (3) which has been extracted due to dental caries long ago. On intra-oral examination it was established that both the maxillary 1st molars i.e. 16 (3) and 26 (14) were missing. However, since 26 (14) was recently extracted, the space loss was small with adequate space available for placement of a prosthodontic implant. On the contrary, there was not only insufficient space for prosthetic replacement 16 (3), but additionally 17 (2) was mesially tipped and rotated mesio-palatally in the space of missing tooth. (Fig. 1 and 2) Similar findings were confirmed both in the orthopantamogram and the intra-oral periapical radiograph (IOPAR). (Fig. 4 and 10 a.) It has been well documented that when the first permanent molar is lost during childhood or early adolescence and is not adequately restored, the second molar drifts mesially and the premolars often tip distally and rotate as space opens between them. Deviation from normal tooth alignment brings changes in gingival and bone architecture. As the teeth move, the adjacent gingival tissue becomes folded and distorted, forming a plaque-harboring pseudo-pocket that may be virtually impossible for the patient to clean. Progressive disease follows in the form of inflammation, loss of attachment and caries. When these conditions exist, stability cannot be restored by mere fabrication of a prosthesis. Correction of the acquired deformities must be accomplished prior to restoration. Repositioning the teeth eliminates this potentially pathologic condition and has the added advantage of simplifying the ultimate restorative procedures.15 The significance of pre-restorative orthodontics has been well-documented in the literature.16-18

Since, there was insufficient space to place the prosthodontic implant in the region of 16 (3), the patient was referred to the orthodontic clinic to regain the space for insertion of an implant. Similar findings were reported on orthodontic examination. The case presented with proclined maxillary and mandibular anteriors, mild spacing in the maxillary anteriors and crowding in the mandibular anterior region, incompetent lips and acute naso-labial angle. The case was diagnosed as Angle’s Class I malocclusion with bimaxillary dentoalveolar protrusion with missing 16 (3) and 26 (14). The patient was advised to go for comprehensive orthodontic treatment for the holistic correction of the underlying malocclusion requiring extraction of all 1st premolars followed by replacement of 16 (3) and 26 (14). However, the patient refused any extractions and the orthodontic therapy. Thus, considering the scenario and the demand of the patient, the case was planned for adjunctive orthodontic therapy. We planned to distalize and upright 17 (2) with a mini-screw anchored distalizing – uprighting Jig assembly. No forces were applied to the anterior teeth. Except for the bondable molar tube on 17 (2) no other appliance was used.

Procedure Examination of the IOPAR of the concerned region i.e. between the maxillary right 1st and 2nd premolars (14 & 15)/(5 & 4) showed comparatively parallel alignment of their roots, (Fig.4 and 10 a.) allowing sufficient space for placement of the mini-screw. The area of placement of the mini-screw was made aseptic and an infiltration of local anesthesia was given. A self drilling mini-screw of 7 mm length and 1.8 mm diameter (ORLUS, Korea) was inserted between the roots of the two premolars. (Fig. 6) The distalizing jig consisted of a 019 x 025 stainless steel wire in 022 slot buccal tube which was bonded to 17 (2). (Fig.5) An open coil NiTi spring was used to deliver the required distalizing force to the molar (NiTi open coil spring of dimension - .012 x .030, ortho organizers,inc.), and the stainless steel wire extended 3mm distal to the distal end of the molar tube. Crimpable stops were secured using a hook crimping plier which in turn activated the assembly. (Fig.6 and 7)

Immediate loading of the implant was done with an initial distalizing force of 75 grams using a NiTi coil spring. The force was doubled to 150 gms post 4-weeks of micro-implant installation.19-20 The orthodontic treatment phase was completed in less than 5 months time. After 3 months of retention (Fig. 9), prosthetic implants were installed (Fig. 10 d.) and the final prosthesis was seated after a healing period of 3 months. (Fig. 10, 11, 12 and 13) Thus, the total treatment took less than 1 year to conclude.

Conclusion

The use of TADs for reinforcement of orthodontic anchorage has become increasingly popular in the recent years, especially in adult patients who often reject to wear fully bonded appliances for various reasons and frequently present with compromised hard and soft tissue architecture. Bearing in mind this fact, mini-screws have evolved as a breakthrough in the orthodontic treatment mechanics. They are not only remarkably convenient but also, time saving and produce good treatment results with significantly reduced need for patient compliance (maintenance of oral hygiene however, is required in the region of the screw installed).21-22

This case demonstrates that mesialized and rotated maxillary second molars due to premature and prolonged loss of adjacent tooth can be distalized and uprighted easily and without any untoward side effects on anterior teeth and without any use of orthodontic brackets using direct mini-screw anchorage with absolutely no patient discomfort and with a predictable mechanics and outcome.

References

1. Stern N., and Brayer L.; Collapse of the occlusion. J. Oral. Rehabil. 2: 1, 1975. 2. Becker A., Zalkind M., Stern N.: The tilted posterior tooth Part II : Biomechanical therapy. J. Prosthet. Dent. 48: 149, 1982. 3. Proffit W.R. Contemporary Orthodontics, 2nd ed. St Louis: Mosby- Yearbook, 1993:307. 4. Park Y.C., Hwang HS, Lee JS. Atlas of Contemporary Orthodontics. Vol II. Seoul: Shinhung, 2003:210-215.) 5. Kraal, J.H.; Digiancinto, J.J.; Dail, R.A.; Lemmerman, K.; and Peden, J.W.: Periodontal conditions in patients after molar uprighting, J. Prosth. Dent. 43:156-162, 1980.

6. Lubow, R.M.; Cooley, R.L.; and Kaiser, D.: Periodontal and restorative aspects of molar uprighting, J. Prosth. Dent. 47:373376, 1982.

7. Tuncay, O.C.; Biggerstaff, R.H.; Cutcliffe, J.C.; and Berkowitz, J.B.: Molar uprighting with Tloop springs, J. Am. Dent. Assoc. 100:863-866, 1980.

8. Roberts, W.W.; Chacker, F.M.; and Burstone, C.J.: A segmental approach to mandibular molar uprighting, Am. J. Orthod. 81:177-184, 1982.

9. Weiland, F.J.; Bantleon, H.P.; and Droschl, H.: Molar uprighting with crossed tipback springs, J. Clin. Orthod. 26:335-337, 1992.

10. Capelluto, E. and Lauweryns, I.: A simple technique for molar uprighting, J. Clin. Orthod. 31:119-125, 1997.

11. Shellhart, W.C. and Oesterle, L.J.: Uprighting molars without extrusion, J. Am. Dent. Assoc. 130:381-385, 1999.

12. Park, H.S.: The skeletal cortical anchorage using titanium microscrew implants, Kor. J. Orthod. 29:699-706, 1999.

13. Park, H.S.; Bae, S.M.; Kyung, H.M.; and Sung, J.H.: Microimplant anchorage for treatment of skeletal Class I bialveolar protrusion, J. Clin. Orthod. 35:417-422, 2001.

14. Park, H.S., Kyung, H.M.,and Sung. J.H.: A Simple Method of Molar Uprighting with MicroImplant Anchorage, J. Clin. Orthod. 36:592-596, 2002.

15. Schluger S., Yuodelis R.A., and Page R.C: Periodontal disease. Philadelphia, 1977, Lea and Febinger, P 94.

16. Brown, I.S.: The effect of orthodontic therapy on certain types of periodontal defects. I. Clinical findings. J. Periodontol. 44:742,1973.

17. Hood, J.A.A, Farah, J.W., and Craig, R.G.: Modification of stresses in alveolar bone induced by a tilted molar. J. Prosthet. Dent. 34:415,1975.

18. Stern, N., Revah, A., and Becker, A.: The tilted posterior tooth. Part I: Etiology, syndrome and prevention. J. Prosthet. Dent. 46:404,1981.

19. Cacciafesta, V., Bumann, A., CHO, H.J., Graham, J.W., Paquette, D., Park, H.S., Scheffler,N.: JCO Roundtable skeletal anchorage Part 2. J. Clin. Orthod. 43:365-378, 2009.

20. Luzi, C., Verna, C., Melsen, B. Immediate loading of orthodontic mini-implants: A histomorphometric evaluation of tissue reaction. Eur. J. Orthod. 31:21-29, 2009.

21. Jung, M.H., and Kim, T.W.: Biomechanical Considerations in Treatment with Miniscrew Anchorage Part 1 The Sagittal Plane. J. Clin. Orthod. 42:79-83, 2008.

22. Park H.S., Jeong S.H., Kwon O.W. Factors affecting the clinical success of screw implants used as orthodontic anchorage. Am. J. Orthod. 130:18–25, 2006.

Figure captions

Fig. 1 - (a). Intra-oral occlusal photograph. (b).Schematic presentation of mesio-palatal rotation along with concomitant mesial displacement of 17 (2) in the available space of 16 (3) due to prolonged loss of 17 (2). Note: 26 (14) was also missing, however; since it was a recent extraction thus, there was no associated space loss. Also, there was no rotation or tipping of 27 (15) established. Fig. 2 – Intra-oral photographs showing rotation and mesial tipping of 17 (2). Fig. 3 - Schematic representation depicting mesially tipped and extruded maxillary 2nd molar, with associated loss of space of 16 (3) due to forward displacement of 17 (2). Fig. 4 – Orthopantamogram of the patient showing 17 (2) mesially tipped in the extraction space of 16 (3) with mesialization and extrusion of the same. On the contrary, though 26 (14) was also extracted however, 27 (15) was neither mesialized nor extruded as it was a recent extraction. Fig. 5 – (a). Schematic representation of the Molar distalizing Jig assembly (Colored arrows designate the direction of force and moments generated. Mini-screw was placed between the two premolars and 019 x 025 SS wire with an open-coil NiTi spring with a crimpable stop constituted the assembly.) (b). The distalizing Jig made of 019 x 025 SS wire with a NiTi open coil spring with a crimpable stop in place.

Fig. 6 – The Molar distalizing jig in-situ. Restorative composite placed over the head of the TAD to avoid any irritation to the surrounding tissues. (a) Pre-activation buccal view. (b) Post-activation of coil spring with crimpable stop. Fig. 7 – The Molar distalizing jig in-situ.

(a). Intra-oral occlusal view with the jig activated by compressing the open-coil NiTi spring with the help of crimpable stops. (b) Intra-oral close-up occlusal view. Fig. 8 – Schema of the moments generated by distalizing force (F) in the sagittal (a).and the occlusal plane (b). and the uprighting moment (clockwise) generated by the couple created at the wire-tube interface. Fig. 9 – Intra-oral photographs of 17 (2), post distalization and uprighting (buccal and occlusal views) with the bonded stainless steel retainer in place. (Post 5 months of active treatment) (a). Buccal, intra-oral close-up view. (b). Occlusal intra-oral close-up view. Fig. 10– Series of Intra-oral radiographs demonstrating the various stages of treatment of 17 (2). (a). Pre-treatment IOPAR (b). Shows the distalizing jig ligated and activated. (c). Shows midtreatment x-ray of 17 (2). (d). Post- installation of implant in the regained space of 16 (3) and final prosthesis in place. Fig. 11- Intra-oral occlusal and buccal views of the case, post-distalization and restoration. Note the excellent cusp-to-fossa occlusion achieved. Fig. 12 - The orthopantamogram of the patient post placement of the implant retained prostheses in relation to 16 (3) and 26 (14). Note the parallelism of the roots and the implant in the first quadrant along with the leveled occlusal plane. Fig. 13 – Intra-oral radiograph showing the prosthodontic implant with satisfactorily contoured restoration in place.

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