Treating Adult Patients with Bilateral Posterior Crossbite, Vertical Growth Pattern and Class II Division 1 Malocclusion with the Invisalign System

Home , Clear aligners, Crossbite, Dental surgery, Elastics (orthodontics), Interproximal reduction, Intrusion (orthodontics)

Case Report

Dr Dan Smethurst BDS, FDSRCS, MOrth RCS, MScD

This case report is intended for dental and healthcare professionals, and is subject to applicable local laws, regulations and guidelines. INVISALIGN, CLINCHECK, and ITERO ELEMENT, among others, are trademarks and/or service marks of Align Technology, Inc. or one of its subsidiaries or affiliated companies and may be registered in the U.S. and/or other countries. Clinical findings IV. Initial ClinCheck treatment plan • Class II division 1 incisor relationship. • Class III skeletal base. The patient, KJ, was 30 years of age at the time of first presentation. KJ was concerned with • 1/2 unit Class II right buccal his narrow smile and protrusive teeth. He was not comfortable wearing conventional braces. segment relationship. • Class I left buccal segment relationship. • 5 mm overjet. • Upper and lower centre lines deviated to the left of facial midline by 2 mm. • Asymmetric upper arch with mesial movement of right buccal segment. I. Intra- and extra-oral images before treatment • Reduced overbite and vertical growth pattern. • Bilateral posterior crossbite with palatally inclined upper right molars and broad lower arch. • Bolton’s discrepancy with mandibular excess 3-3 of 3.52 mm and 6-6 of 4.02 mm.

Treatment goals • Align arches. the small upper lateral incisors was also • Conventional vertical rectangular incorporated into the treatment plan. • Reduce overjet. attachments on lower 3-3 and upper 2-2 teeth to assist with root control. • Correct bilateral posterior crossbite. 3. Vertical dimension: an increase in vertical dimension can occur with • Button cutouts palatal of upper first • Control vertical dimension during upper upper arch expansion due to palatal molars and buccal of lower first arch expansion. cusps swing down. This can be more molars for cross elastics. Pre-Treatment • Maintain positive overjet and overbite pronounced in non-growing individuals • IPR of 0.5 mm on 2-2 lower teeth Clinical presentation during correction of underlying skeletal due to lack of ramus growth. for control of lower incisors during Class III malocclusion. Therefore, good torque control of alignment and to maintain a positive KJ presented with Class III skeletal the upper buccal segments was overjet, and 0.2 mm IPR on teeth base and Class II division 1 incisor Treatment approach important during posterior crossbite correction. The full occlusal coverage 11 and 21 to reduce black relationship with a 5 mm overjet. Correction of posterior crossbites with of aligners also provided excellent triangle formation. He also had bilateral posterior upper arch expansion in non-growing control of the vertical dimension, Refinement phase individuals can give rise to unwanted due to posterior dental intrusion. It is • Optimised Attachments crossbite with palatally inclined gingival recession in patients with a thin important to note that while posterior - Optimised Root Control upper right molars and a broad gingival biotype. KJ’s treatment involved dental intrusion is a benefit in terms uprighting of the palatally inclined of control of the vertical dimension, Attachments on teeth 11 and 13. lower arch. upper right molars; thus, for this reason, it has the unwanted effect of Class - Optimised Deep Bite significant expansion was deemed possible III changes due to counterclockwise Attachments on teeth 35 and 44. III. Cephalometric radiograph without the likelihood of gingival recession. mandibular rotation. - Optimised Rotation Attachments II. Panoramic radiograph before treatment before treatment KJ’s case involved correction in all on teeth 23, 34 and 43. three dimensions. Treatment details - Optimised Multiplane Attachment on tooth 12. 1. Transverse dimension: expansion was Active treatment time supported with cross elastics (Ormco • Conventional attachments used were 19 months. Bears 1/4’’ 4.5 oz elastics) from the rectangular horizontal attachments palatal of upper first molars to the Aligners used on teeth 16, 24, 26 and 45 to assist buccal of lower first molars. in open bite closure and long vertical 2. Horizontal dimension: Class III changes • 21 + 9 upper aligners. attachments on teeth 33 and 42 to occurred during alignment owing to • 24 + 9 lower aligners. control root uprighting. the underlying Class III skeletal pattern, • Precision Cuts for Class II elastics proclination of the crowded lower Attachments on the right and Class III on the arch during alignment as well as the Initial treatment phase left to improve the buccal underlying Bolton’s discrepancy with • Optimised Attachments mandibular excess excess 6-6 of 4.02 segment relationships. mm. This was controlled by significant - Optimised Root Control Attachments • IPR of 0.2 mm on the 2-2 lower teeth interproximal reduction (IPR) of KJ’s on teeth 23, 24, 35 and 45. (not all the 2-2 lower teeth underwent very broad lower incisor teeth. Opening - Optimised Rotation Attachments IPR during treatment with the a small space for possible build-up of on teeth 13, 15, 34 and 44. initial aligners).

This case report is intended for dental and healthcare professionals, and is subject to applicable local laws, regulations and guidelines. This case report is intended for dental and healthcare professionals, and is subject to applicable local laws, regulations and guidelines. INVISALIGN, CLINCHECK, and ITERO ELEMENT, among others, are trademarks and/or service marks of Align Technology, Inc. or one of INVISALIGN, CLINCHECK, and ITERO ELEMENT, among others, are trademarks and/or service marks of Align Technology, Inc. or one of its subsidiaries or affiliated companies and may be registered in the U.S. and/or other countries. its subsidiaries or affiliated companies and may be registered in the U.S. and/or other countries. V. Intra- and extra-oral images after treatment VI. Panoramic radiograph after treatment

Post-Treatment

VII. Cephalometric radiograph after treatment

Treatment outcome teeth movement, such as maxillary expansion, was necessary, especially A pleasing aesthetic and functional in this non-growing patient. The use of occlusion was achieved despite us not cross elastics allowed good tracking of attempting to fully correct the right buccal the treatment throughout the planned segment relationship. The ‘end-on-end’ tooth movements. right buccal segment relationship was due in part to mesial migration of the upper • Full occlusal coverage of all erupted teeth allowed excellent control of the right buccal segment, an asymmetric vertical dimension in this patient with a upper arch, Bolton’s discrepancy with vertical growth pattern. relative mandibular excess, and small teeth 12 and 22. • After using Invisalign aligners, the patient found laboratory made vacuum- • Posterior crossbite correction was Further improvements in the right buccal formed retainers unsatisfactory as achieved whilst maintaining good segment could have been made by he found them of poor quality and fit control of the vertical dimension, even additional IPR in the lower anterior region compared to his aligners. The ability in this non-growing individual. so as to allow mesial movement of the to order Vivera retainers from the last lower right quadrant as well as additional • The Invisalign System may be viewed as active stage of treatment is a great the treatment modality of choice when space opening of tooth 12 to allow benefit from a practice management distalisation of the upper right quadrant. treating posterior crossbites in patients and patient comfort perspective. with a vertical growth pattern. However, the patient wanted to avoid restorative veneer build-ups of teeth 12 and Impact on clinical practice Author disclosure 22. Additionally, distalisation in the upper • The Invisalign System can be viewed Dr Dan Smethurst was provided an honorarium from right quadrant was not advisable due to as the appliance of choice for the Align Technology, Inc., for his contribution towards the the underlying Class III skeletal pattern. creation of this case report. treatment of patients with an increased This treatment decision to not fully correct vertical dimension, especially when Dr Dan Smethurst the right buccal segment relationship was correcting posterior crossbites that can independent of the Invisalign System. Dan Smethurst was born in Britain and graduated from also have a bite-opening effect. the University of Wales, College of Medicine in Cardiff KJ has been referred for the removal of • The use of intermaxillary cross in 1989 with a Bachelor of Dental Surgery. Following his unopposed and overerupted tooth 18. graduation, he came to New Zealand to work at the elastics can assist complicated and University of Otago Dental School in 1990. Thereafter, unpredictable tooth movements, such Dr Smethurst moved to Auckland to work in Clinical tips as maxillary expansion. private practice. In 1994 Dr Smethurst returned to the UK to gain • Bonded buttons enabled easy • The ‘bite-plane effect’ of clear aligners Fellowship in Dental Surgery of the Royal College placement of cross elastics in this aides the correction of crossbites. of Surgeons (England), whilst working as a Senior adult patient and did not compromise House Officer in oral and maxillofacial surgery. In 1999 he completed his orthodontic specialist training aligner retention and fit. This was (with distinction) at the University of Wales College of important for the success of this case, Conclusion Medicine and gained Membership in Orthodontics at the Royal College of Surgeons (Edinburgh). as consistent cross elastic wear was • This case demonstrates how a imperative throughout treatment to He spent the next 5 years working in a specialist complicated case in a non-growing orthodontic practice in Cardiff and worked part-time at support the planned expansion. individual involving correction in the a nearby hospital treating complex orthodontic cases The use of intermaxillary cross transverse, horizontal and vertical with specialist dental and surgical colleagues. In 2004 • Dr Smethurst returned to New Zealand, where he now elastics to bonded buttons to assist dimensions can be achieved with the works exclusively in private practice in Tauranga. He complicated and unpredictable Invisalign System. lectures on the Invisalign System in New Zealand.