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Correction of severe tooth rotations using clear aligners: a case report

November 2012
Australian Orthodontic Journal 28(2):245-9

Source
PubMed

Authors:

Gianluigi Frongia

University of Turin

Tommaso Castroflorio

University of Turin

The present adult patient case report shows the correction of a crossbite malocclusion and severe tooth rotations treated with the Invisalign system. A 27-year-old female with a dental crossbite (24, 34), severe rotations of two lower incisors (more than 40 degrees) and malalignment of the upper and lower arches is described. The Invisalign system was treatment planned to correct the malocclusion. The treatment goals of crossbite, rotation and malalignment correction were achieved after 12 months of active aligner therapy. The overbite improved (2.5 mm before treatment, 1 mm at the end); the dental crossbite, the crowding and the severe tooth rotations (with a mean of 2 degrees of improvement per aligner) were corrected. After treatment, the dental alignment was considered excellent. The presented case indicates that the Invisalign system can be a useful appliance to correct a dental malocclusion involving severe rotations.

(A) Initial ClinCheck ® , (B) final ClinCheck ® and (C) superimposition of A and B. The ClinCheck ® simulation shows the degrees of correction of the rotations. (E) Initial intra-oral photo on the lower arch, (F) final intra-oral photo on the lower arch and (D) summary of changes of (E) and (F). The correction of the rotations on the ClinCheck ® and on the photos are similar.

…

(A) Initial and (B) final panoramic x-ray (anterior region only). No obvious root resorption is present after treatment.

…

Figures - uploaded by Tommaso Castroflorio

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Content uploaded by Tommaso Castroflorio

Content may be subject to copyright.

Australian Orthodontic Journal Volume 28 No. 2 November 2012

Background: The present adult patient case report shows the correction of a cross bite malocclusion and severe tooth rotations

treated with the Invisalign system.

Methods: A 27-year-old female with a dental crossbite (24, 34), severe rotations of two lower incisors (more than 40°)

and malalignment of the upper and lower arches is described. The Invisalign system was treatment planned to correct the

malocclusion.

Results: The treatment goals of crossbite, rotation and malalignment correction were achieved after 12 months of active aligner

therapy. The overbite improved (2.5 mm before treatment, 1 mm at the end); the dental crossbite, the crowding and the severe

tooth rotations (with a mean of 2° of improvement per aligner) were corrected.

Conclusions: After treatment, the dental alignment was considered excellent. The presented case indicates that the Invisalign

system can be a useful appliance to correct a dental malocclusion involving severe rotations.

(Aust Orthod J 2012; 28: XXX)

Received for publication: September 2011

Accepted: July 2012

Correction of severe tooth rotations using clear

aligners: a case report

Gianluigi Frongia and Tommaso Castroﬂorio

Private practice, Turin, Italy

Introduction

In recent years, increasing numbers of adult patients

have sought orthodontic treatment

and expressed

a desire for aesthetic alternatives to conventional

ﬁxed appliances.

The possibility of using clear

overlay appliances to achieve an orthodontic result

was introduced in 1946, when Kesling

devised

the concept of using a series of thermoplastic tooth

positioners to progressively move malaligned teeth to

impoved positions.

In 1997, Align Technology (Santa Clara, CA, USA)

adapted and incorporated modern technologies to

introduce the Invisalign system which made Kesling’s

concept a feasible, efﬁcent and effective orthodontic

treatment option. In 2000, Boyd et al.

published

the ﬁrst case report on the use of clear aligners and

indicated that the primary beneﬁt of the Invisalign

appliance was the superior aesthetics during treatment,

compared with metal braces.

The Invisalign system

5,6

is based on a clear sequential

appliance (aligners) made from a translucent

thermoplastic material, which is worn for at least

20 hours per day. According to current protocols,

the appliances are replaced on a bi-weekly regimen

which incorporates a progressive alignment of up to

0.25 mm translation or up to 2 degrees of rotation per

tooth per aligner.

Malocclusions treated with the Invisalign system

initially involved only mild crowding of 3-6

millimetres.

Recent data has expanded the use of

this appliance to incorporate molar distalisation,

extraction cases,

the treatment of open bites,

crossbites,

deep bites,

Class II

and Class III

corrections

and orthodontic-periodontic problems.

Rotation is an orthodontic movement reported to be

difﬁcult to achieve and control with the Invisalign

system. Previous studies

14,15

have demonstrated

that aligners were not able to control the rotation

of canines requiring rotational movements greater

Gianluigi Frongia: gianluigi_frongia@msn.com; Tommaso Castroﬂorio: tcastroﬂorio@libero.it

Australian Orthodontic Journal Volume 28 No. 2 November 2012

FRONGIA AND CASTROFLORIO

Figure 1. Intra-oral photos at the beginning of the treatment.

Figure 2. Teleradiography and superimposition of the latero-lateral

cephalometry. Dark grey represents the Bolton Standard chart and light

grey represents the cephalometry of the patient.

than 15 degrees, which underlined the fact that the

effectiveness of canine derotation was questionable.

Recently, many new biomechanical features have

been promoted by Align Technology to improve

the predictability of aligner treatment. In particular,

the G3 and G4 platforms introduced a collection of

newly engineered attachments to improve control of

desired tooth movements, including dental rotation

and root tipping. The present case report describes an

adult patient in whom the correction of a crossbite

malocclusion with severe tooth rotations was

successfully achieved with the Invisalign system.

Case report

A 27-year-old female patient with a dental crossbite

(24, 34), severe rotations of two lower incisors

(more than 40°) and malalignment of the upper and

lower arches presented for orthodontic treatment

(Figure 1). Informed consent was obtained from

the patient who underwent examination and record

taking. This involved clinical, orthodontic and

temporomandibular disorder (TMD) evaluations,

a radiographic assessment (panoramic), lateral

cephalometry (Figure 2), stone casts, intra-oral

(Figure 1) and extra-oral photos, and upper and

lower arch impressions to generate a ClinCheck

assessment.

The clinical examination revealed a molar and canine

Class I relationship, an overjet of 1 mm, an overbite

of 2.5 mm, a crossbite between teeth 24 and 34,

upper and lower crowding, and severe rotations of

lower incisors (32 rotated 45° and 42 rotated 44°).

The assessment of the temporomandibular joints

revealed no signs and/or symptoms of TMD.

Cephalometric analysis

Cephalometric analysis showed a skeletal Class I-III

relationship according to Steiner

17,18

with an ANB

angle of -1 degree (mean of 2° ± 2°), a hypodivergent

craniofacial form indicated by a SN-GoGn angle of

27 degrees (mean of 32° ± 4°), an interincisal angle of

Australian Orthodontic Journal Volume 28 No. 2 November 2012

CORRECTION OF SEVERE TOOTH ROTATIONS USING CLEAR ALIGNERS

Figure 3. Initial stage of the ClinCheck

. Figure 4. Final predicted stage of the ClinCheck

145 degrees (mean of 135° ± 5°), a counterclockwise

growth rotation according to Siriwat and Jarabak,

with a PostHt/AntHt ratio of 72% (mean of 60-64%)

and a counterclockwise growth rotation according to

Bjork

of 387 degrees (mean of 396° ± 6°).

ClinCheck

and aligners

Invisalign treatment was planned to correct the dental

crossbite, the severe rotations of 32 and 42 and the

upper and lower malalignment. The ﬁnal ClinCheck

(version 2.9, Align Technology Inc., Santa Clara,

CA, USA) provided 17 aligners for the upper arch

and 23 aligners for the lower arch (Figures 3 and

4). The duration of therapy was assessed to require

approximately 12 months. Each aligner was to be

worn for two weeks. No inter-proximal reduction

(IPR) was indicated for the correction of the crowding.

Retention attachments were planned on several upper

teeth (13, 14, 23, 24, 26, 27) and on several lower

teeth (32, 33, 34, 36, 42, 43, 44, 45).

Treatment progress was checked every 4 weeks (2

aligners every month) using the ClinCheck

analysis

to evaluate changes, patient compliance and bonded

attachment stability. A new aligner was inserted at

each appointment. The precise relationship and

connection between the attachments, the aligner

and the teeth, provided an indication of the positive

progress of treatment. As compliance is critical in all

orthodontic therapy, the patient was instructed to

wear the aligners full time, except for eating and tooth

brushing. The aligners were worn for a minimum of

20 hours per day.

Results and Discussion

A patient with a dental crossbite, severe rotations of

lower incisors and malalignment of the upper and

Figure 5. Intra-oral photos at the end of treatment.

Australian Orthodontic Journal Volume 28 No. 2 November 2012

FRONGIA AND CASTROFLORIO

Figure 6. (A) Initial ClinCheck

, (B) ﬁnal ClinCheck

and (C)

superimposition of A and B. The ClinCheck

simulation shows the

degrees of correction of the rotations. (E) Initial intra-oral photo on

the lower arch, (F) ﬁnal intra-oral photo on the lower arch and (D)

summary of changes of (E) and (F). The correction of the rotations on the

ClinCheck

and on the photos are similar.

Figure 7. (A) Initial and (B) ﬁnal panoramic x-ray (anterior region only).

No obvious root resorption is present after treatment.

lower arches was treated with the Invisalign appliance.

Patient compliance was high throughout treatment

and excellent oral hygiene was maintained. The molar

and canine Class I relationships were maintained, as

well as the overjet. The overbite improved (2.5 mm

pretreatment, 1 mm post-treatment); the dental

crossbite, the crowding (Figure 5) and the severe tooth

rotations (with a mean of 2° of correction per aligner)

were corrected (Figure 6). No obvious root resorption

was radiographically evident at the end of therapy

(Figure 7). A lower ﬁxed retainer was bonded from the

right ﬁrst premolar to left ﬁrst premolar to maintain

lower incisor alignment. Retention in the upper arch

was provided by the last aligner used as a nocturnal

removable retainer.

In 2003, Joffe

deﬁned the criteria for selecting

Invisalign patients and emphasised that caution should

be taken in speciﬁc malocclusions involving severe

tooth rotations (more than 20°). In the presented

case, a correction of 45 degrees and 44 degrees for

teeth 32 and 42 respectively, was achieved with 23

lower aligners, using accepted treatment protocols.

The rotated incisors were derotated approximately 2

degrees per aligner and the ﬁnal result was achieved

in 12 months. This result may be due to the recent

signiﬁcant improvement in Invisalign technology

which has allowed the treatment of more difﬁcult

malocclusions over a shorter time. The introduction

of the G3 and G4 platforms with new smart force

features has also potentially allowed more predictable

tooth movement.

Conclusion

The Invisalign system can be a useful therapeutic

tool to correct a dental malocclusion involving severe

rotations. The presented case conﬁrmed that:

1. The correction of a crossbite in an adult patient is

possible with clear aligners.

2. Severe tooth rotations of lower incisors (up to 45°)

can be corrected with clear aligners.

Acknowledgment

The logistical support of Equipe Dentale Srl was

greatly appreciated.

Corresponding author

Dr Gianluigi Frongia

Corso Vittorio Emanuele II, 170,

10138 Torino

Italy

Email: gianluigi_frongia@msn.com

Australian Orthodontic Journal Volume 28 No. 2 November 2012

CORRECTION OF SEVERE TOOTH ROTATIONS USING CLEAR ALIGNERS

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Introduction: This study aimed to assess the association between nonextraction clear aligner therapy (CAT) and the presence of alveolar bone dehiscences (ABDs) and fenestrations (ABFs) in adults with mild-tomoderate crowding. Methods: Cone-beam computed tomography images from 29 adults were obtained before and immediately after nonextraction CAT. Total root lengths were evaluated in axial and cross-sectional slices. Linear measurement for dehiscence (LM-D) was defined as the distance between the alveolar crest to the cementoenamel junction of each root (critical point set at 2 mm). Linear measurement for fenestration (LM-F) was recorded when the defect involved only the apical one-third of a root (critical point set at 2.2 mm). Counts of ABDs/ABFs and magnitudes of LM-Ds/LM-Fs were recorded before and immediately after nonextraction CAT at buccal and lingual root surfaces. Binary logistic regression analyses and repeated measures analyses of variance were performed. Results: Counts of ABDs/ABFs and magnitudes of LM-Ds/ LM-Fs increased at most jaw locations and root surfaces. Nonextraction CAT was associated with an increased presence of ABDs and ABFs. Nonextraction CAT was associated with a higher magnitude of LMDs but not LM-Fs. Conclusions: Immediate posttreatment cone-beam computed tomography scans showed that nonextraction CAT is associated with increased ABDs and ABFs in adults with mild-to-moderate crowding.

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This study sought to systematically review the literature to determine whether clear aligner treatment results in different patient perceptions of treatment process and outcomes compared with conventional fixed appliance treatment. A systematic review was conducted to identify studies that examined differences in patient perceptions between clear aligners and conventional fixed appliance treatment. Studies were identified through searching relevant terms using PubMed and Embase. Following review of identified articles, key information about the studies including study design, setting, comparison groups, sample size/response rate, study location, primary outcomes, and statistical tests used were extracted. A total of 13 articles were identified that met the inclusion criteria for this study. These studies described a variety of outcomes which were divided into two broad categories: treatment process (pain, chewing, speech, daily routine, etc.) and treatment outcomes (satisfaction level, smile outcome perceptions, etc.). There was the strongest evidence that clear aligners had a positive impact with respect to treatment process compared with fixed orthodontic appliances. This study highlights that clear aligners may be effective for improving treatment-process-related outcomes among orthodontic patients. More studies need to be conducted to determine whether clear aligners have a beneficial impact with respect to treatment outcomes.

Three dimensional diagnosis and orthodontic treatment of complex malocclusions with the Invisalign® appliance

Article

Jan 2001
Semin Orthod

The Invisalign system in adult orthodontics: Mild crowding and space closure cases

Article

Jan 2000
J Clin Orthod

The use of cephalometrics as an aid to planning and assessing orthodontic treatment. Report of a case

Article

Oct 1960
Am J Orthod

Cecil C. Steiner

Cephalometrics for U and me

Article

Oct 1953
Am J Orthod

Cecil C. Steiner

Three-dimensional diagnosis andorthodontic treatment of complex malocclusions with the invisalign appliance

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Dec 2001
Semin Orthod

Recent developments in software technology have made it possible to create a virtual three-dimensional (3D) model of the dental arches from digitally scanned impressions of a patient's dentition. This model may then be manipulated with software to produce stages of tooth movement from the initial malocclusion to the final desired occlusion. A stereolithographic model is made for each stage of tooth movement which is the basis for construction of a series of clear, thin, overlay appliances. These appliances are worn full time by the patient to move the teeth according to the programmed stages of movement. Malocclusions involving mild to moderate crowding and space closure have been proven to be successfully treated with this appliance. The present study shows orthodontic treatment of patients with more complex orthodontic problems, requiring dental expansion, Class II and Class III correction, extraction treatment and correction of overbite. Experience with this appliance, thus far, has demonstrated excellent patient compliance with less discomfort, and improved esthetics and oral hygiene, when compared with fixed orthodontic appliances. Orthodontic treatment with this appliance is a potentially useful alternative approach to fixed appliances for treatment of a variety of malocclusions in patients with fully erupted permanent teeth.

Northcroft Lecture: How has the spectrum of orthodontics changed over the past decades?

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Treatment of anterior open bite with the Invisalign system

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