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 Table of Contents  
Year : 2018  |  Volume : 52  |  Issue : 1  |  Page : 51-59

Orthodontic space closure using simple mechanics in compromised first molar extraction spaces: Case series

1 Senior Orthodontist, Private Practitioner, Smiles N Faces Orthodontic Clinic, Vileparle West, Mumbai, Maharashtra, India
2 Associate Orthodontist, Private Practitioner, Mumbai, Maharashtra, India

Date of Submission11-Aug-2017
Date of Acceptance11-Dec-2017
Date of Web Publication18-Jan-2018

Correspondence Address:
Dr. Prashant M Dhole
Smiles N Faces, 8, Gautam Ashish Society, VM Road, Vile Parle West, Mumbai - 400 056, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jios.jios_146_17

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Orthodontic treatments involving missing or compromised first permanent molars are often challenging cases to treat considering the loss of potential anchor tooth. The case series presents orthodontic treatment in three patients with mutilated/absent first permanent molars. The treatment goals were to be accomplished by extraction of compromised teeth and retention of healthy dentition. The diagnosis and problem list needed extractions to accomplish the treatment goals. The possibility of extracting compromised first permanent molars instead of other healthy teeth was considered. A setup was done to determine the final occlusion in asymmetric extraction cases. Fixed appliances were used with simple mechanics without any additional anchorage devices. Case-based retention protocols were followed. All the three patients achieved the predetermined treatment objectives of improved esthetics and healthy and stable functional occlusion. The simple and efficient mechanics and finishing techniques for comprehensive orthodontic treatment with first molar extractions presented in the report should help clinicians when treating similar patients.

Keywords: Asymmetric extractions, buccal bonded retainer, molar extractions, sliding mechanics, V bends

How to cite this article:
Dhole PM, Maheshwari DO. Orthodontic space closure using simple mechanics in compromised first molar extraction spaces: Case series. J Indian Orthod Soc 2018;52:51-9

How to cite this URL:
Dhole PM, Maheshwari DO. Orthodontic space closure using simple mechanics in compromised first molar extraction spaces: Case series. J Indian Orthod Soc [serial online] 2018 [cited 2019 May 19];52:51-9. Available from: http://www.jios.in/text.asp?2018/52/1/51/223650

  Introduction Top

The choice of extractions for an orthodontic case depends on several factors; to name a few – space required, skeletal pattern, desired final occlusion, compromised teeth, and patient compliance.[1] Extraction of first permanent molars is a less preferred choice of an orthodontist since they provide a potential source of anchorage due to their large root surface area. The 6 year molars are the early permanent teeth to erupt and they have high prevalence of caries.[2] Compromised first molars would need endodontic treatment or prosthetic replacement still having questionable prognosis. Extractions of such compromised first molars to accomplish orthodontic treatment objectives would be a better choice if the case demands extractions.[3]

Orthodontic treatment involving extraction of first molars is more challenging, especially when subjected to asymmetric extraction on either side of the arch.[4] However, the decision to extract a healthy tooth versus the compromised first molars for orthodontic treatment would mean space closure in a more natural way. Three case reports are presented in this article in which first molars were previously extracted or were planned to extract for space requirements during orthodontic treatment. Special attention and precautions to be taken in finishing cases with asymmetric extractions are presented below.

  Case Reports Top

Case 1 – patient CS

Diagnosis and problem list

A 17 years, 4 months old female reported with chief concern of crowded and protruded teeth. She had a convex facial profile with competent lips. Lower lip was thick and everted with a deep mentolabial sulcus [Figure 1]. The upper and lower arches exhibited moderate crowding with Class I canine and molar relation bilaterally; 4 mm overjet and 3 mm overbite [Figure 1]. Orthopentamogram (OPG) showed full complement of teeth, developing third molars, and 16 and 46 endodontically treated with prosthesis [Figure 2]. Cephalometric evaluation showed a Class I skeletal base, average growth pattern, and proclined upper and lower incisors [Figure 2] and [Table 1].
Figure 1: Patient CS, pretreatment intraoral and extraoral photos

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Figure 2: Patient CS, pretreatment orthopantomography and lateral cephalogram

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Table 1: Patient CS, Case 1 - lateral cephalogram table: pre- and post-treatment values

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Treatment objectives

  1. Unraveling of crowding and alignment of upper and lower arches
  2. Correct overbite and overjet relationship
  3. Retraction of anterior teeth to improve facial profile
  4. Improve smile esthetics and functional occlusion.

Treatment alternatives

  1. Extraction of four premolars, one in each quadrant. However, this plan would mean extraction of healthy teeth and retention of first molars on the right side which were endodontically treated and would need replacement of crowns later after orthodontic treatment
  2. Extraction of first molars on the right side and one premolar each on the left side in upper and lower arches. This would eliminate the compromised right first molars without the need for any prosthetic work required later after orthodontic treatment. Hence, the patient opted for this plan.

Treatment plan

A Kesling setup was done to determine the best fit of occlusion as the case demanded asymmetric extractions. Extractions of 16, 25, 34, and 46 were done [Figure 3]; 25 and 34 were chosen as they had aberrant morphology in the mesiodistal dimension and would occupy more space. During leveling and alignment with round archwires, lacebacks were used to generate space in anterior segment for unraveling of crowding. This would prevent round-tripping by avoiding flaring of incisors. The anterior teeth were sequentially ligated to archwire once enough space was available to align. Space closure was carried with friction mechanics on 19 × 25 SS archwire with V-bend mechanics. Toe-in bends were given for right second molars to avoid mesiolingual rotation during space closure. Retention included upper and lower fixed retainers along with Essix retainers for upper and lower arches.
Figure 3: Patient CS, during treatment photos showing 16, 25, 34, and 46 extracted and alignment phase continued

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Treatment results

The active treatment time was 23 months. Class I buccal segment relation was achieved bilaterally [Figure 4]. The increased overjet and overbite were reduced; upper and lower dental midlines were coincident to the facial midlines with esthetically, pleasing profile [Figure 4]. OPG shows the right side third molars guided in occlusion [Figure 5]; lateral cephalogram shows the reduced proclination of upper and lower incisors [Figure 5], [Figure 6] and [Table 1].
Figure 4: Patient CS, posttreatment intraoral and extraoral photographs

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Figure 5: Patient CS, posttreatment orthopantomography and lateral cephalogram

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Figure 6: Patient CS, pre- and post-treatment lateral cephalogram superimposition

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Case 2 – patient SR

Diagnosis and problem list

A 13 years, 4 month old female complained of protruded and crowded teeth. She had a convex facial profile, incompetent lips and interlabial gap of 6 mm, thick everted lower lip, and mentalis strain on closure [Figure 7]. The upper arch was constricted with dental crossbite in upper right posterior region, erupting 13 and 23, retained 55, and fractured 16 [Figure 7]. The lower arch was moderately crowded. She had an excess overjet of 6 mm and deepbite of 4 mm with Class I canine and molar on right and left sides. The upper dental midline was canted to the right, and lower dental midline was shifted to the right by 3 mm to the facial midline. She had class 1 canine and molar relation bilaterally. OPG revealed full complement of teeth with developing third molars in all four quadrants, retained 55, distally inclined and impacted 15, grossly carious 16 [Figure 7] and [Figure 8]. Cephalometric examination revealed mild skeletal Class II tendency, average growth pattern, and proclined upper and lower incisors [Figure 8] and [Table 2].
Figure 7: Patient SR, pretreatment intraoral and extraoral photos

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Figure 8: Patient SR, pretreatment orthopantomography and lateral cephalogram

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Table 2: Patient SR, Case 2 - lateral cephalogram table: pre- and post-treatment values

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Treatment objectives

  1. Eliminate transverse discrepancy-correct crossbite of upper right posterior region
  2. Relieve crowding and protrusion in upper and lower arches
  3. Attain normal overjet and overbite relation
  4. Improve profile and lip competency, smile esthetics, and functional occlusion.

Treatment alternatives

  1. Nonextraction treatment plan with extraction of retained 55 followed by alignment of all teeth. However, this plan would not improve the profile of the patient and hence was rejected
  2. Extraction of all first premolars followed by leveling and space closure. However, this would retain 16 with questionable prognosis and sacrifice a healthy premolar
  3. Extraction of 16, 24, 34, and 44. The patient went ahead with this plan as the tooth with poor prognosis was extracted and she would retain a healthy premolar.

Treatment plan

A Kesling setup determined the final occlusion [Figure 13] and [Figure 14]. Extraction of 16, 24, 34, and 44 was done [Figure 9]. Alignment with NiTi archwires included bend backs to avoid proclination of incisors. The narrow archform and crossbite were corrected with archwire expansion in SS archwires with palatal crown torque in posterior segment to avoid palatal cusp hang. Space closure was done on 19 × 25 SS, the upper right segment used binary mechanics to avoid second molar rotation. However, some mesial-in rotation of upper second molar was desired to sock the mesiobuccal cusp in embrasure of lower first and second molar. This would also occupy the increased space available on upper right due to molar extraction.
Figure 13: Patient SR, study models mounted on three-point articulator for Kesling setup, teeth to be extracted marked on the models

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Figure 14: Final setup after alignment and space closure on Kesling setup. Performed and alignment continued of upper and lower arches

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Figure 9: Patient SR, during treatment photos, asymmetric extractions – 16, 24, 34, and 44

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Treatment results

The total treatment time was 20 months. Class I canine relation bilaterally, Functional class III molar relation on the right, and Class I molar relation on the left were obtained [Figure 10]. The upper dental midline was coincident to facial midline; lower midline was parallel to the upper dental midline but 1 mm to the right which was acceptable. The profile had improved, and lip competence was achieved due to improved inclination of incisor teeth [Figure 10], [Figure 11], [Figure 12] and [Table 2]. The patient is on periodic recall to check the eruption of third molars. Upper and lower fixed retention were given along with wraparound removable retainers.
Figure 10: Patient SR, posttreatment intraoral and extraoral photos

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Figure 11: Patient SR, posttreatment orthopantomography and lateral cephalogram

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Figure 12: Patient SR, pre- and post-treatment lateral cephalogram superimposition

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Case 3

Diagnosis and problem list

An 18-year-8-month-old female reported with a chief complaint of back teeth tilted in extraction space of first molars. She had no relevant medical history but dental history revealed extractions of all first molars as they were badly broken down. Extraoral examination revealed a symmetrical face, straight profile with competent lips [Figure 15]. Intraoral examination revealed Class I canine relation on the right and end-on on the left, mild spacing in lower arch with lower second molars tilted in extraction spaces, noncoincident upper and lower dental midlines, 2 mm overjet and overbite [Figure 15]. OPG showed extraction space of upper first molars whereas lower extraction spaces were occupied by mesially tilted second molars [Figure 16]. Lateral cephalogram findings included normal positioned maxilla and mandible, average growth pattern, and normally inclined upper and lower incisors [Figure 16] and [Table 3].
Figure 15: Patient PS, pretreatment intraoral and extraoral photos

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Figure 16: Patient PS, pretreatment orthopantomography and lateral cephalogram

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Table 3: Patient PS, Case 3 - lateral cephalogram table: pre- and post-treatment values

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Treatment objectives

  1. Upright the lower second molars to harmonize the interdental crestal bone morphology to prevent future periodontal problems
  2. Guide the eruption and position of all third molars
  3. Close spaces in lower arch and establish Class I canine relation on the left
  4. Improve smile esthetics and functional occlusion.

Treatment alternatives

  1. Uprighting of lower second molars and establish space for replacement of all first molars with prosthesis after completion of orthodontic treatment. This option would require extraction of lower third molars to make room for second molars to upright. Compensating extractions of upper third molars would also be needed [5]
  2. Uprighting of lower second molars followed by mesial movement of these teeth to occupy first molar extraction spaces. Guide eruption of third molars in the arch to increase the occlusal table. This treatment option was chosen as it would maintain the natural dentition with no need for further prosthesis and extractions.

Treatment plan and mechanics

The challenging part of this case was to maintain the sagittal position of the upper and lower incisors allowing only the mesial movement of molars since no change in facial esthetics was expected. Hence, all the conventional mechanics aimed to increase the anchorage value of the anterior segment without use of any temporary anchorage devices. The space available to be closed at occlusal level of lower second premolars and molars was 2.5 and 1.5 mm on the right and left, respectively, but the actual space calculation would be the distance the second molar roots had to travel to upright and close the space through the dense cortical bone of the lower arch. This distance was estimated to be 11 and 15 mm on the right and left, respectively [Figure 16]. A cinch back was given in the round and rectangular NiTi archwires to lock the arch length allowing only mesial movement of molar roots to upright; space closure was accomplished on a 19 × 25 SS with V-bend principle keeping the moment arm close to the second molars along with light space closing elastics. Crimpable stops were added distal to second premolar brackets, and palatal/lingual root torque was added in upper and lower incisors to reinforce anchorage. Light Class II elastics (3/8”, 2oz) were given on the left side to achieve a Class I relation [Figure 17].
Figure 17: Patient PS, during treatment intraoral photos, space closure continued

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Treatment results

Total treatment time was 29 months. A Class I canine and molar relation was obtained bilaterally maintaining the original overjet and overbite and straight profile [Figure 18], [Figure 19] and [Table 3]. OPG revealed a complete space closure of first molar extraction spaces with bodily movement of upper second molars and upright lower second molars [Figure 20]. This generated a good morphology of alveolar crest which was lost originally due to extractions giving a healthy periodontium. Buccal bonded retainer was given to keep the extraction spaces closed in addition to lingual bonded retainers.
Figure 18: Patient PS, posttreatment intraoral and extraoral photos, buccal bonded retainers across extracted teeth

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Figure 19: Patient PS, posttreatment orthopantomography and lateral cephalogram

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Figure 20: Patient PS, pre- and post-treatment lateral cephalogram superimposition

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  Discussion Top

Orthodontic treatment with extraction of molars is technically more complex due to number of factors, especially in adult patients. In general, the space to be closed is greater than premolar spaces rendering critical anchorage and longer treatment time. Often such cases exhibit some degree of periodontal or endodontic involvement. Hence, there is a need for greater control over orthodontic mechanics to reduce the side effects of space closure. Therefore, good finishing results can be more challenging to achieve.[6]

The decision of asymmetric extraction of molars on one side versus premolars on the other was taken in the above cases as these molars were endodontically treated or broken down with poor prognosis. Extraction of a compromised tooth than a healthy tooth was aimed considering the longevity of dentition. The challenging part of these cases would be to maintain the upper and lower dental midlines coincident to the facial midlines since these asymmetric extractions on the right and left side of the first molars and first premolars would generate unequal spaces on both sides of the arch. Space closure should be planned such that the midlines remain coincident and the arches should not get skewed maintaining a Class I buccal segment relation bilaterally.[7] The space closure objectives should establish the posterior occlusion before finishing the anterior segment as predetermined on a Kesling setup.[8] The final occlusion should be aimed such that it provides a mutually protected occlusion.

The presence of healthy third molars with normal anatomy will compliment first molar extractions to provide an occlusal table sufficient for function.[9] The ideal alveolar dimensions to succeed in closing first molar space is 6 mm or less in the mesiodistal direction and 7 mm in the buccolingual direction.[10] A longstanding extraction space makes space closure difficult. Hence, one can resort to the temporary anchorage devices to assist the tooth movements planned.[11],[12] A split-crest technique for narrow ridge expansion can also be done as for implant placement.[13],[14]

Orthodontic movement in adults – compared to young adults – presents greater resistance and entails a greater likelihood of loss of alveolar bone crest height, gingival recession, and root resorption, in addition to greater difficulty in maintaining the closed space, i.e., decreased stability.[15]

To reduce these effects, orthodontists must use an efficient mechanism to ensure delivery of light forces and increase the interval between activations so that the tissues involved have time to recover and avoid development of soft-tissue clefts which have tendency to open spaces. This approach greatly increases treatment time.

Anchorage loss occurs more easily in the upper arch, and therefore, when one needs to utilize the space created with extraction of the first molar to dilute crowding or even retract anterior teeth, one should establish appropriate anchorage mechanisms. In cases where there is no patient cooperation, but the patient agrees with skeletal anchorage, this is the best option to avoid anchorage loss.[16]

Placement of the orthodontic appliance must be complete and include third molars if possible, starting with the initial alignment and leveling phase. Orthodontic auxiliaries can assist uprighting of molar teeth tipped/tilted in extraction spaces. This procedure seeks to accomplish parallelism between the roots of second molars and premolars during space closure. Attachments can also be positioned more mesial on second molar crowns to reduce a rotation tendency when closing spaces.

Retention in first molar extraction should include a bonded wire on buccal surface of second premolar and molar to avoid opening of extraction spaces in first molar region.

  Conclusion Top

Orthodontic space closure treatment in patients with extracted or compromised first molars can be done with simple mechanics to obtain good clinical results. In cases of asymmetric extractions, the final occlusion should always be planned before commencing treatment.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/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


Conflicts of interest

There are no conflicts of interest.

  References Top

Carlos de Oliveira RA, Martins de Oliveira RR, Lourenço RF, Melo PM, Lacerda dos SR. Tooth extraction in orthodontics: An evaluation of diagnostic elements. Dent Press J Orthod 2010;15:134-57.  Back to cited text no. 1
Al-Samadani KH, Ahmad MS. Prevalence of first permanent molar caries in and its relationship to the dental knowledge of 9-12-year olds from Jeddah, Kingdom of Saudi Arabia. ISRN Dent 2012;2012:391068.  Back to cited text no. 2
Ong DC, Bleakley JE. Compromised first permanent molars: An orthodontic perspective. Aust Dent J 2010;55:2-14.  Back to cited text no. 3
Williams JK, Gowans AJ. Hypomineralised first permanent molars and the orthodontist. Eur J Paediatr Dent 2003;4:129-32.  Back to cited text no. 4
Travess H, Roberts-Harry D, Sandy J. Orthodontics. Part 8: Extractions in orthodontics. Br Dent J 2004;196:195-203.  Back to cited text no. 5
Schroeder MA, Schroeder DK, Santos DJ, Leser MM. Molar extractions in orthodontics. Dent Press J Orthod 2011;16:130-57.  Back to cited text no. 6
Jacobs C, Jacobs-Müller C, Luley C, Erbe C, Wehrbein H. Orthodontic space closure after first molar extraction without skeletal anchorage. J Orofac Orthop 2011;72:51-60.  Back to cited text no. 7
Araújo TM, Fonseca LM, Caldas LD, Costa-Pinto RA. Preparation and evaluation of orthodontic setup. Dent Press J Orthod 2012;17:146-65.  Back to cited text no. 8
Ay S, Agar U, Biçakçi AA, Köşger HH. Changes in mandibular third molar angle and position after unilateral mandibular first molar extraction. Am J Orthod Dentofacial Orthop 2006;129:36-41.  Back to cited text no. 9
Hom BM, Turley PK. The effects of space closure of the mandibular first molar area in adults. Am J Orthod 1984;85:457-69.  Back to cited text no. 10
Kyung SH, Choi JH, Park YC. Miniscrew anchorage used to protract lower second molars into first molar extraction sites. J Clin Orthod 2003;37:575-9.  Back to cited text no. 11
Nagaraj K, Upadhyay M, Yadav S. Titanium screw anchorage for protraction of mandibular second molars into first molar extraction sites. Am J Orthod Dentofacial Orthop 2008;134:583-91.  Back to cited text no. 12
Blus C, Szmukler-Moncler S. Split-crest and immediate implant placement with ultra-sonic bone surgery: A 3-year life-table analysis with 230 treated sites. Clin Oral Implants Res 2006;17:700-7.  Back to cited text no. 13
Sethi A, Kaus T. Maxillary ridge expansion with simultaneous implant placement: 5-year results of an ongoing clinical study. Int J Oral Maxillofac Implants 2000;15:491-9.  Back to cited text no. 14
Kessler M. Interrelationships between orthodontics and periodontics. Am J Orthod 1976;70:154-72.  Back to cited text no. 15
Uribe F, Janakiraman N, Fattal AN, Schincaglia GP, Nanda R. Corticotomy-assisted molar protraction with the aid of temporary anchorage device. Angle Orthod 2013;83:1083-92.  Back to cited text no. 16


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14], [Figure 15], [Figure 16], [Figure 17], [Figure 18], [Figure 19], [Figure 20]

  [Table 1], [Table 2], [Table 3]


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