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 Table of Contents  
CASE REPORT
Year : 2018  |  Volume : 52  |  Issue : 3  |  Page : 204-209

Nonextraction treatment with en-masse distalization of maxillary dentition using miniscrews


1 Dr, Deshmukh's Orthodontic Center; Professor Bharati Vidyapeeth University Dental College and Hospital, Pune, Consultant Deenanath Mangeshkar Hospital, Pune, Maharashtra, India
2 Dr, Deshmukh's Orthodontic Center, Pune, Maharashtra, India

Date of Submission13-Nov-2017
Date of Acceptance27-Apr-2018
Date of Web Publication18-Jul-2018

Correspondence Address:
Dr. Kinjal J Vadera
“Devikripa” Shri Dashbhuja Co-Op Hous. Soc., Karve Road, Paud Phata, Pune - 411 038, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jios.jios_235_17

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  Abstract 


Miniscrews have been increasingly used in orthodontics for distalization of the maxillary molars and also the entire arch. The two case reports in this article describe the en-masse distalization of the maxillary arch in Class II patients with different growth patterns with the help of four miniscrews in the arch. The placement of two miniscrews and their relative position on either side of the maxillary arch were used to control the magnitude and direction of force for distalization of the entire arch. At the end of the treatment, Class I molar and canine relationships were achieved in both the cases without the need for extraction or loss of anchorage.

Keywords: Class II malocclusion, en-masse distalization, miniscrews


How to cite this article:
Deshmukh SV, Vadera KJ. Nonextraction treatment with en-masse distalization of maxillary dentition using miniscrews. J Indian Orthod Soc 2018;52:204-9

How to cite this URL:
Deshmukh SV, Vadera KJ. Nonextraction treatment with en-masse distalization of maxillary dentition using miniscrews. J Indian Orthod Soc [serial online] 2018 [cited 2019 Jun 19];52:204-9. Available from: http://www.jios.in/text.asp?2018/52/3/204/237103




  Introduction Top


The goal of any orthodontic treatment is to achieve desired tooth movement with a minimum number of undesirable side effects.[1] Strategies for anchorage control have been a major contributing factor in achieving successful orthodontic treatment. Edward H. Angle was one of the earliest to advocate the use of equal and opposite appliance forces to control anchorage. Traditional methods of reinforcing anchorage such as increasing the number of teeth bilaterally and using the musculature or extraoral devices have unwanted side effects or require patient compliance.[2] Miniscrews have overcome many of these problems regardless of whether a single molar or the entire posterior segment is to be moved. Sagittal movement of the dentition in nonextraction cases is often difficult and time-consuming.[3] Sagittal movement carried out with the help of skeletal anchorage minimizes the side effects, no special compliance is required, and the incisor positions and facial profile can be efficiently controlled.[4],[5],[6] There are many Class II cases where the face dictates nonextraction treatment. Transition from extraction to nonextraction treatment using miniscrews for en-masse distalization of the maxillary dentition in select Class II cases has been discussed in this article through two case reports. All cephalometric analyses and superimpositions in both the case reports have been carried out using Dolphin 10.2 version imaging software.


  Case Reports Top


Case 1

A 20-year-old female patient presented with a chief complaint of crooked teeth in both arches. Intraoral examination showed a Class II division 2 malocclusion with an end-on molar relationship on both the sides and a canine relationship of Class II on the right side and end-on on the left side. She had a deep bite (6-mm overbite) and an overjet of 4 mm. Her upper left first premolar was in scissor bite. The upper arch exhibited a crowding of 5 mm. She had a straight profile with a sharp nose and a prominent chin [Figure 1]a and [Figure 1]b.
Figure 1: (a) Pretreatment extraoral photographs of the patient showing a straight profile and a deep bite. (b) Pretreatment intraoral photographs of the patient showing Class II division 2 malocclusion

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Cephalometric analysis revealed a skeletal Class I relation with an ANB of 3.1° and a horizontal growth pattern [Figure 2]a, [Figure 2]b and [Table 1]. [Figure 2]c shows the pretreatment orthopantomogram (OPG) of the patient.
Figure 2: (a) Pretreatment lateral cephalogram. (b) Digital tracing of the pretreatment lateral cephalogram. (c) Pretreatment orthopantomogram

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Table 1: Pretreatment cephalometric values

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Treatment objectives

These include

  • Correction of deep bite and crowding
  • Establishing a Class I molar and canine relationship
  • Maintaining the facial profile.


After discussion with the patient, nonextraction therapy with en-masse distalization of the upper arch for the correction of molar and canine relationships using two miniscrews on either side of the arch was planned.

Both the arches were bonded with 0.022” MBT prescription brackets. After initial leveling and alignment, two miniscrews were placed between the roots of first and second premolars and the second premolar and first molar, respectively, on either side. With 0.019” × 0.025” posted SS archwires in place, force was applied using power chains. The first chain was placed from the distal screw to the canine hook and the second one from the mesial screw to the posted hooks on both the sides. The force on each chain was measured at 100 gm. Hence, a total force of 200 gm was applied on either side to carry out the distalization of the whole maxillary dentition [Figure 3]a and [Figure 3]b.
Figure 3: (a) Intraoral photographs. Power chains from the miniscrews for distalization. (b) Intraoral periapical radiographs showing the position of the miniscrews between the first and second premolars and between the second premolar and first molar

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After 8 months of distalization, Class I molar and canine relationships were achieved. Class II settling elastics were worn by the patient during the finishing stage [Figure 4].
Figure 4: Intraoral photographs. Class II settling elastics during the finishing stage

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The posttreatment cephalogram shows that a Class I molar relation is achieved [Figure 5]a. The posttreatment cephalogram and its superimposition with the pretreatment cephalogram are shown in [Figure 5]b.
Figure 5: (a) Posttreatment lateral cephalogram. (b) Superimposition of the pre- - and posttreatment lateral cephalograms. (c) Posttreatment orthopantomogram

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[Table 2] depicts the posttreatment cephalometric values. [Figure 5]c shows the posttreatment OPG of the patient.
Table 2: Posttreatment cephalometric values

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After finishing and debonding, the case shows a settled Class I occlusion with an improvement in bite and smile line [Figure 6]a and [Figure 6]b.
Figure 6: (a) Posttreatment extraoral photographs of the patient showing an improvement in smile line. (b) Posttreatment intraoral photographs of the patient showing Class I molar and canine relationships and an improvement in bite

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Case 2

An 11-year-old female patient reported to the clinic with a chief complaint of forwardly placed teeth and a gummy smile. Intraoral examination showed end-on molar and canine relationships on both the sides with an overbite of 3.5 mm and an overjet of 5 mm. The upper arch showed mild crowding, and there was a deep curve of Spee in the lower arch. The upper midline was deviated to the left by 2 mm. The upper and lower incisors were proclined. She had a convex profile with protrusive and hypotonic lips [Figure 7]a and [Figure 7]b.
Figure 7: (a) Pretreatment extraoral photographs of the patient showing a convex profile with protrusive and hypotonic lips. (b) Pretreatment intraoral photographs

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Cephalometric analysis revealed a skeletal Class II relation with an ANB of 7.7° and a vertical growth pattern [Figure 8]a, [Figure 8]b and [Table 3]. The pretreatment OPG of the patient does not show any evidence of third molars in the upper arch [Figure 8]c.
Figure 8: (a) Pretreatment lateral cephalogram. (b) Digital tracing of the pretreatment lateral cephalogram. (c) Pretreatment orthopantomogram

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Table 3: Pretreatment cephalometric values

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Treatment objectives

These include

  • Correction of deep bite
  • Correction of proclination
  • Establishing a Class I molar and canine relationship
  • Correcting the convex facial profile
  • Correction of gummy smile.


After evaluating the facial features and discussion with the patient, nonextraction therapy with en-masse distalization and intrusion of the upper arch for the correction of end-on molar and canine relationships using two miniscrews on either side of the arch was planned. Although there was proclination of anterior teeth in both the arches, it was felt that in this particular case, extractions would not benefit the patient's facial features and also the lips would remain protrusive.

Both the arches were bonded with 0.022” MBT prescription brackets. The treatment protocol with miniscrews for this patient was different from the first case as the patient exhibited a vertical growth pattern. After initial leveling and alignment, two miniscrews were placed between the roots of the second premolar and first molar and the first and second molars, respectively, on either side. With 0.019” × 0.025” posted SS archwires in place, power chains from the distal screw to the canine hook and from the mesial screw to the posted hooks on both the sides were attached. Again, a total force of 200 gm was applied on either side to carry out the distalization of the whole maxillary dentition [Figure 9]a and [Figure 9]b.
Figure 9: (a) Intraoral photographs. Power chains from the miniscrews for distalization. (b) Intraoral periapical radiographs showing the position of the miniscrews between the second premolar and first molar and between the first and second molars

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Once the vertical control during distalization was achieved, the miniscrew between the first and second molars was removed and placed between the first and second premolars on both the sides for more intrusive effect on the anteriors [Figure 10]a and [Figure 10]b.
Figure 10: (a) Intraoral photographs. Power chains from the miniscrews for more intrusive effect on the anteriors. (b) Intraoral periapical radiographs showing the shifted position of the miniscrews between the first and second premolars and between the second premolar and first molar

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The distalization was complete in 8 months. The treatment was completed with the canines and molars in Class I relation.

The posttreatment cephalogram shows that a Class I molar relation is achieved [Figure 11]a. The posttreatment cephalogram and its superimposition with the pretreatment cephalogram are shown in [Figure 11]b. [Table 4] depicts the posttreatment cephalometric values. The posttreatment OPG shows the development of tooth bud for the upper right third molar and the presence of lower left and right third molars [Figure 11]c.
Figure 11: (a) Posttreatment lateral cephalogram. (b) Superimposition of the pretreatment and posttreatment lateral cephalograms. (c) Posttreatment orthopantomogram

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Table 4: Posttreatment cephalometric values

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The posttreatment extraoral photographs show a reasonable correction of gummy smile [Figure 12]a and [Figure 12]b.
Figure 12: (a) Posttreatment extraoral photographs of the patient showing a reasonable correction of gummy smile. (b) Posttreatment intraoral photographs of the patient showing Class I molar and canine relationships

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  Discussion Top


Molar distalization in adults was initially considered difficult to achieve without the potential side effects of forward movement of premolars and incisors.[7],[8] With the help of miniscrews, distalization of the entire arch has become possible with simultaneous retraction of incisors, without the need to overcome round tripping. Single miniscrews have been used to achieve distalization, but studies have shown that force applied for distalization using a single miniscrew for anchorage may be insufficient for effective distalization compared to the use of two miniscrews. Furthermore, the magnitude and direction of force vector given to the arch are better controlled with the use of two miniscrews.

The center of resistance (Cres) of the maxillary dentition has been shown to be located around the middle area of the premolar roots. The position of the miniscrew with respect to the Cres determines the magnitude and direction of force vector and helps in achieving arbitrary arch rotation.[9]

Jeon and Yu stated that more interproximal alveolar bone is available between the maxillary second premolar and first molar roots and between the maxillary first molar and second molar roots than in other locations.[3]

An intrusive force vector should accompany any distalization, more so in high-angle cases. When two miniscrews are used for distalization, two force vectors are created which can be arranged on either side of the Cres (front and behind) of the arch so that moment components get canceled effectively. Simply put, when a single force is applied to a long structure oriented anteroposteriorly (dental arch), it has the effect of tilting the arch at one end, while two forces on either side of its center more efficiently lift the arch and distalize it.

It is recommended that in a patient with a horizontal growth pattern, as in the first case, the placement of the miniscrews should be between the first and the second premolars and the second premolar and first molar as it causes effective distalization. In the second case with a vertical growth pattern, the miniscrews were placed between the second premolar and first molar and between the first and second molars. This generated a higher vertical component of force in the region of the molars, thereby preventing their extrusion during distalization. This helped in controlling the mandibular plane angle.

In the above-mentioned cases, distalization with two miniscrews corrected the molar and canine relationships to Class I along with correction of incisor inclination and deep bite.

During distalization, the status of the second molars and the posterior space distal to the first molar should be considered. In adolescent patients who are still growing, the maxillary posterior area including the tuberosity continues to grow as the maxillary molars move distally. Ricketts indicator for position of upper molar should be taken into consideration to decide whether distalization of upper molars is warranted. According to the indicator, the distal surface of upper first molar to PtV (pterygoid vertical) should be equal to the sum of patient's age and 3 mm.[10] If the measured value on the cephalogram is less, then distalization should not be attempted. In addition, distal movement of maxillary molars in adults has several limitations, such as presence of a strong second molar (sometimes third molar also) and limited tuberosity area. Extraction of third molars should be considered before distal movement after carefully inspecting the status of the second and third molars as well as the maxillary tuberosity.[11]

The placement of two miniscrews on either side of the arch to distalize the entire maxillary dentition is quite technique sensitive. Both the miniscrews have to be placed at a minimum of 60°–70° angulation, and the distal miniscrew is recommended to be placed at a higher level than the mesial miniscrew. This in the authors' experience has helped in seamless distalization of the maxillary arch without the miniscrew interfering with the roots of the maxillary teeth during distalization. However, there always remains a possibility that the roots may come in contact with the miniscrews, thereby interfering with the distalization. If one comes across such a situation, it is always prudent to shift the position of the miniscrews so that distalization is completed.

Critical appraisal – the mandibular lateral incisor roots in the second patient should have been uprighted [Figure 11]c.


  Conclusion Top


The resultant pattern of maxillary dentition during distalization is closely associated with the relationship between the center of resistance and the line of force.[9] Appropriate placement of the miniscrews in the arch is a key to effective and efficient en-masse distalization of the entire maxillary arch.

The placement of miniscrews in the first case with a horizontal growth pattern was between the premolars and the second premolar and the first molar. The placement in the second case with a vertical growth pattern was between the second premolar and first molar and the first and second molars. This helped in controlling the extrusion of the molars during distalization.

Finally, it is important that the distalization of the arch should be carried out within anatomic and biologic limits of tooth movement.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Proffit WR. Contemporary Orthodontics. 2nd ed. St. Louis: Mosby Yearbook; 1993.  Back to cited text no. 1
    
2.
Lee JS, Kim JK, Park YC, Vanarsdall RL. Applications of Orthodontic Mini-Implants. Canada: Quintessence Publishing Co.; 2007.  Back to cited text no. 2
    
3.
Jeon JM, Yu HS, Baik HS, Lee JS. En-masse distalization with miniscrew anchorage in class II nonextraction treatment. J Clin Orthod 2006;40:472-6.  Back to cited text no. 3
    
4.
Park HS, Kwon TG, Sung JH. Nonextraction treatment with microscrew implants. Angle Orthod 2004;74:539-49.  Back to cited text no. 4
    
5.
Gelgör IE, Büyükyilmaz T, Karaman AI, Dolanmaz D, Kalayci A. Intraosseous screw-supported upper molar distalization. Angle Orthod 2004;74:838-50.  Back to cited text no. 5
    
6.
Nanda R. Biomechanics in Clinical Orthodontics. Philadelphia: W.B. Saunders; 1996.  Back to cited text no. 6
    
7.
Byloff FK, Darendeliler MA. Distal molar movement using the pendulum appliance. Part 1: Clinical and radiological evaluation. Angle Orthod 1997;67:249-60.  Back to cited text no. 7
    
8.
Byloff FK, Darendeliler MA, Clar E, Darendeliler A. Distal molar movement using the pendulum appliance. Part 2: The effects of maxillary molar root uprighting bends. Angle Orthod 1997;67:261-70.  Back to cited text no. 8
    
9.
Bechtold TE, Kim JW, Choi TH, Park YC, Lee KJ. Distalization pattern of the maxillary arch depending on the number of orthodontic miniscrews. Angle Orthod 2013;83:266-73.  Back to cited text no. 9
    
10.
Ricketts RM. Perspectives in the clinical application of cephalometrics. The first fifty years. Angle Orthod 1981;51:115-50.  Back to cited text no. 10
    
11.
Choi NC, Park YC, Lee HA, Lee KJ. Treatment of class II protrusion with severe crowding using indirect miniscrew anchorage. Angle Orthod 2007;77:1109-18.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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