- Short report
- Open Access
Class II subdivision correction with clear aligners using intermaxilary elastics
© The Author(s). 2018
- Received: 26 February 2018
- Accepted: 14 June 2018
- Published: 1 September 2018
To describe an esthetic orthodontic treatment using aligners in an adult patient with class II subdivision associated with crowding and dental crossbite. An 18-year-old hyperdivergent male patient with skeletal class II from mandibular retrusion presented for an orthodontic treatment. Occlusally, the patient presents class II subdivision, crossbite at tooth 4.4, an upper midline deviated towards the left with respect to the lower and facial midlines, and slight crowding in both arches. The patient refused conventional fixed multibracket treatment in favor of aligners. Pre- and post-treatment records as well as 1-year follow-up records are presented.
Treatment objectives were achieved in 12 months, and the patient was satisfied with the functional and esthetic outcomes, which were stable at 1 year.
Combining aligners with appropriate auxiliaries is an efficacious means of resolving orthodontic issues such as class II, dental crossbite, and crowding in a time-frame comparable to that of conventional fixed orthodontics. Furthermore, this system is associated with optimal oral hygiene and excellent esthetics.
Nowadays, there is a growing demand for esthetic treatment among both adolescents  and adults . Indeed, a recent study estimated that 45% of adults are unhappy with their smile and that 20% of these have considered undergoing orthodontic treatment to improve their appearance .
Hence, aligner systems must now be able to treat various types of malocclusion, and over recent years, many studies have shown their great efficacy in correcting crowding, misalignment and diastems, and even complex cases featuring extraction, open-bite, and poor occlusal relationships [4–8].
This case report describes an adult male patient with class II subdivision malocclusion, dental crossbite, and crowding treated successfully with aligners.
Diagnosis and etiology
Clinical examination revealed class II subdivision with lower midline deviation towards the right of the upper midline, dental crossbite, slight crowding in both arches, and small alteration of the upper right lateral incisor morphology.
Pre- and post-treatment cephalometric values
Wits appraisal (mm)
Mand plane to occ plane (°)
U1-palatal plane (°)
Clinical examination showed no sign of bad habits.
As there were no major skeletal discrepancies, a combined orthodontic/surgical approach was ruled out. Fixed multibracket treatment with extraction of four premolars was considered, but also excluded due to potential worsening of the profile. The patient was therefore offered a treatment plan involving unilateral distalization by fixed multibracket appliances in order to center the upper midline with the lower and facial midlines. However, the patient refused this option due to the unsightliness of the device, and we therefore agreed upon a non-extractive treatment with F22 aligners (Sweden & Martina, Due Carrare, Italy) for unilateral distalization and mesialisation of the lower arch in order to correct the class II relationship.
The virtual set-up dictated 20 treatment steps for each arch. To achieve upper midline correction, the plan involved distorotation of teeth 1.6 (22°) and 1.7 (13°) in association with distalization. The use of class II elastics had a double function: the anchorage, used to obtain simultaneous distalization of the elements of the quadrant I and support the correction of the lower midline.
In the lower arch, the plan involved mesorotation of teeth 4.6 and 4.7 associated with mesial tipping. The plan also involved alignment of the arches and retroclination of the upper incisors.
In order to achieve correct alignment and valid intercuspidation, vestibular grip points on teeth 1.6, 1.7, 4.5, 4.4, and 4.3 were planned, alongside 0.2 mm of stripping at each interproximal point in the lower right sector, from the mesial surface of tooth 4.6 to the distal surface of 4.2.
After 10 months of treatment, the treatment objectives had been successfully fulfilled, although it was necessary to plan another three steps per arch for detailed finishing of the case and complete class correction. Specifically, the derotation of teeth 4.5, 1.6, and 1.5 was improved.
The last pair of aligners was used for retention due to the elastic propriety of the thermoplastic material .
Restoration of the 1.2 was performed in order to improve its morphology.
Aligners associated with intermaxillary elastics enabled resolution of the malocclusion within a treatment time comparable with that required for conventional fixed orthodontics, providing the patient with a comfortable, practical, and esthetic appliance. This case report is very similar to those presented in 2010 by Schupp et al. . In our case, in order to prevent unwanted extrusion and/or rotation and further enhance the esthetics, we used notches in the aligners at the upper canines and lower first molars rather than buttons bonded directly onto the teeth for attaching the intermaxillary elastics. Unfortunately, a direct comparison of the cephalometric indices, especially pertaining to the lower incisor proclination, was not possible, as these were not provided in the report.
From a biomechanical perspective, the dental movements occurred as planned, thanks to the fact that they were planned within the correct range of predictability  and the excellent properties of the material that the F22 aligners are made of .
In accordance with findings from Janson et al. , and due to the age of the patient, the movements brought about by the use of intermaxillary elastics were predominantly dentoalveolar in nature and led to a slight reduction in the SNA angle, a slight increase in the IMPA, and retroclination of the upper incisal sector. Their main effect was to provide anchorage for the upper arch, thereby promoting distal tipping and retroclination of the upper incisors.
The treatment plan selected proved to be a winning solution not only in terms of biomechanics, but also as regards esthetics and periodontal health. Indeed, previous studies  have shown that fixed multibracket appliances, whether labial or lingual, are associated with an increase in plaque retention, which in turn may cause an increase in S. mutans concentration and gingival inflammation. Furthermore, the use of such devices can increase the chromium and nickel concentration in a patient’s mucosa, potentially resulting in damage to DNA , whereas aligners have not been linked to any type of cytotoxicity .
Moreover, Abbate et al.  revealed the microbiological and periodontal changes that may occur during orthodontic treatment; comparing aligners and fixed appliances, they found that aligners were associated with greater compliance, better oral hygiene, less accumulation of plaque, and less gingival inflammation than fixed appliances. These findings are in line with those reported in a previous study by Mietheke et al. , and in another that showed an increase in periodontopathic bacteria associated with a worsening of periodontal health in fixed multibracket orthodontics with respect to aligners .
Combined use of aligners and auxiliaries is an efficacious means of resolving orthodontic issues such as class II, dental cross-bite, and crowding within a time-frame comparable to conventional fixed orthodontics, but with excellent esthetics and oral hygiene.
The authors declare that they have not received funding.
Availability of data and materials
The authors declare that the materials are available.
LL is responsible for the treatment planning decision and clinical patient treatment. CA did the article test production. CA had a hand in the digital elaboration set-up and planning. OT led the clinical treatment of the patient. SG contributed in the treatment planning decision and clinical patient treatment. All authors read and approved the final manuscript.
Ethics approval and consent to participate
The study was performed in accordance with the Declaration of Helsinki. It is a case report, and the treatment plan was approved by the Chairman of Postgraduate School of Orthodontics, University of Ferrara.
Consent for publication
Written informed consent was obtained from the patient for publication of this short report and any accompanying images.
The authors declare that they have no competing interests.
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- Walton DK, Fields HW, Johnston WM, Rosenstiel SF, Firestone AR, Chirstensen JC. Orthodontic appliance preferences of children and adolescents. Am J Orthod Dentofac Orthop. 2010;138(6):698.e1–12.Google Scholar
- Feu D, Catharino F, Duplat CB, Capelli Junior J. Esthetic perception and economic value of orthodontic appliances by lay Brazilian adults. Dental Press J Orthod. 2012;17(5):102–14.View ArticleGoogle Scholar
- British Orthodontic Society. News release, www.bos.org.uk/ news/NOWYouGovSurvey. Accessed 9 Apr 2013.
- Boyd RL, Miller RJ, Vlaskalic V. The Invisalign system in adult orthodontics: mild crowding and space clousure cases. J. Clin. Orthod. 2000;34(4):04–203.Google Scholar
- Womack WR. Four-premolar extraction treatment with Invisalign. J Clin Orthod. 2006;40:493–500.PubMedGoogle Scholar
- Hönn M, Göz G. A premolar extraction case using the Invisalign system. J Orofac Orthop. 2006;67:385–94.View ArticlePubMedGoogle Scholar
- Boyd RL. Complex orthodontic treatment using a new protocol for the Invisalign appliance. J Clin Orthod. 2007;41:525–47.PubMedGoogle Scholar
- Boyd RL. Esthetic orthodontic treatment using the Invisalign appliance for moderate to complex malocclusions. J. Dent. Ed. 2008;72:948–67.Google Scholar
- Björk A, Skieller V. Growth of the maxilla in three dimensions as revealed radiographically by the implant method. Br J Orthod. 1977;4:53–64.View ArticlePubMedGoogle Scholar
- Björk A. Prediction of mandibular growth rotation. Am J Orthod. 1969;55:585–99.View ArticlePubMedGoogle Scholar
- Lombardo L, Martines E, Mazzanti V, Arreghini A, Mollica F, Siciliani G. Stress relaxation properties of four orthodontic aligner materials: a 24-hour in vitro study. Angle Orthod. 2017;87(1):11–8.View ArticlePubMedGoogle Scholar
- Schupp W, Haubrich J, Neumann I, Class II. Correction with the Invisalign system. J Clin Orthod. 2010;44(1):28–35.PubMedGoogle Scholar
- Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL. Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review. Angle orthod. 2015;85(5):881–9.View ArticlePubMedGoogle Scholar
- Janson G, Sathler R, Fernandes TM, Branco NC, Freitas MR. Correction of class II malocclusion with class II elastics: a systematic review. Am J Orthod Dentofac Orthop. 2013;143(3):383–92.View ArticleGoogle Scholar
- Lombardo L, Ortan YÖ, Gorgun Ö, Panza C, Scuzzo G, Siciliani G. Changes in the oral environment after placement of lingual and labial orthodontic appliances. Prog Orthod. 2013;11(14):28.View ArticleGoogle Scholar
- Hafez HS, Selim EM, Kamel Eid FH, Tawfik WA, Al-Ashkar EA, Mostafa YA. Cytotoxicity, genotoxicity and metal release in patients with fixed orthodontic appliances: a longitudinal in-vivo study. Am J Orthod Dentofac Orthop. 2011;140(3):298–308.View ArticleGoogle Scholar
- Eliades T, Pratsinis H, Athanasiou AE, Eliades G, Kletsas D. Cytotoxicity and estrogenicity of Invisalign appliances. Am J Orthod Dentofac Orthop. 2009;136(1):100–3.View ArticleGoogle Scholar
- Abbate GM, Caria MP, Montanari P, Mannu C, Orrù G, Caprioglio A, Levrini L. Periodontal health in teenagers treated with removable aligners and fixed orthodontic appliances. J Orofac Orthop. 2015;76(3):240–50.View ArticlePubMedGoogle Scholar
- Miethke RR, Vogt S. A comparison of the periodontal health of patients during treatment with the Invisalign system and with fixed orthodontic appliances. J Orofac Orthop. 2005;66(3):219–29.View ArticlePubMedGoogle Scholar
- Karkhanechi M, Chow D, Sipkin J, Sherman D, Boylan RJ, Norman RG, Craig RG, Cisneros GJ. Periodontal status of adult patients treated with fixed buccal appliances and removable aligners over one year of active orthodontic therapy. Angle Orthod. 2013;83(1):146–51.View ArticlePubMedGoogle Scholar