A novel approach for treatment of theimpacted maxillary incisorMohammed Almuzian, Jimmy Freel, Nicola Cross and Alastair GardnerOrthodontic Department, Glasgow Dental Hospital and School, Glasgow, Scotland, UK

This case report demonstrates a novel treatment approach to deal with a severely rotated and impacted upper

central incisor in an adolescent patient. A precision custom-made gold attachment was fabricated from a prototype

using cone beam computerized tomograph (CBCT) scan data and then used to align and de-rotate the impacted

central incisor.

Key words: precision attachment, CBCT, impacted incisor

Received 24 September 2014; accepted 3 January 2015

IntroductionThe incidence of unerupted maxillary central incisors

during the mixed and early permanent dentition stage

has been reported to be 0.13–2.6% (MacPhee, 1935;

DiBiase, 1969). Missing and unerupted maxillary

incisors have a negative effect on dentofacial appearance(Shaw et al., 1991). An additional impact of missing

maxillary incisors includes speech difficulties particu-

larly with the ‘s’ sound (Weinberg, 1968). The aetiology

of an impacted upper central incisor is multifactorial.

Hereditary factors include supernumerary teeth, cleft lip

and palate, cleidocranial dysostosis, abnormal tooth/

tissue ratio and gingival fibromatosis. Environmental

factors can include trauma, early extraction or loss ofdeciduous teeth, retained deciduous teeth, cystic forma-

tion and thick bone or tissue (Yaqoob et al., 2010).

The management of impacted maxillary incisors is the

subject of specific clinical guidelines in the UK (Yaqoob

et al., 2010). However, this situation can present

significant challenges to the clinician in terms ofmanagement. Successful treatment depends on the

interaction of many factors. Among these are patient

age, compliance, aetiology of impaction, accurate

localisation of impacted tooth, treatment mechanics,

amount of keratinized gingivae, presence of dilacera-

tions and the method of surgical exposure (DiBiase,

1971; Kolokithas and Karakasis, 1979; Munns, 1981;

Vermette et al., 1995; Noar and Gaukroger, 2000).

Clinical and radiographic methods exist to allow

localisation of the impacted central incisor (Moyers,

1976). Radiological methods frequently involve the right-

angle, magnification (Brook, 1974; Armstrong et al., 2003;

Chaushu et al., 1999) and parallax techniques (Clark,

1910). If conventional radiographs cannot provide

enough information regarding the clinical condition, thencone beam computerized tomography (CBCT) is justified

on an individual basis (Isaacson et al., 2008).

This paper describes a novel method of utilizing a

CBCT scan to localize an impacted central incisor,

assess the space requirement, plan the orthodontic

mechanics and design and construct a precision attach-

ment. The custom-made attachment was prescribed to

perform particular tooth movements, which would bedifficult to achieve by conventional methods.

HistoryA fit and well 15-year-old male was referred to the

Orthodontic department at Glasgow Dental Hospital and

School, complaining of an unerupted upper right perma-

nent central incisor. There was a history of early loss of the

deciduous right central incisor due to previous trauma,which might explain the patient’s clinical presentation.

Extra-oral assessmentThe patient presented with a mild class II skeletal base

with average vertical proportions, mild retrogenia and

no obvious asymmetries. The lips were competent with

normal incisor show at rest and smile (Figure 1).

Intra-oral assessmentThe patient was in the permanent dentition with no

active dental disease. The incisor relationship was class

III with an edge-to-edge occlusion. There was moderate

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CLINICAL SECTION Journal of Orthodontics, Vol. 000, 2014, 000–000

Address for correspondence:

Email: dr_muzian@hotmail.com# 2014 British Orthodontic Society DOI 10.1179/1465313315Y.0000000002

crowding in the upper arch and mild crowding in the

lower arch. The molar relationship was class I bilat-

erally, with the upper centreline shifted by 3 mm to the

right side (Figure 2).

Radiographic assessmentAn orthopantomogram (Figure 3) and lateral cephalo-

metric radiograph (Figure 4a) showed the maxillary

right central incisor to be impacted, severely rotated and

located within the line of the arch. The cephalometric

tracing confirms the clinical diagnosis (Figure 4b).

Aims of the treatmentThe aims of treatment were as follows:

N secure and maintain dental health throughout treatment;

N relieve the crowding and align teeth with early de-

rotation of the impacted tooth;

N surgical exposure of the upper right central incisor

(UR1) (closed surgical exposure) and bonding of a

precision attachment;

N achieve a class I incisor, molar and canine relationshipwith normal overjet and overbite;

N long-term retention.

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Figure 2 Intra-oral views

Figure 1 Extra-oral views

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2 Almuzian et al. Clinical Section JO Month 2014

Treatment plan and rationaleAll treatment options were explained to the patient and

his parent, including:

1. accepting the position and monitoring the impacted

tooth;

2. orthodontic camouflage on a non-extraction basis

using upper and lower fixed appliances to open

space for the impacted UR1, followed by surgical

exposure of the impacted tooth and bonding of a

precision attachment to align the tooth. If the tooth

failed to respond to active traction then the

treatment would be modified to options 3 or 4);

3. orthodontic camouflage using upper and lower

fixed appliances to regain space for the UR1,

followed by restorative replacement. The impacted

incisor would be monitored or extracted;

4. orthodontic camouflage based on extraction of the

impacted tooth, using upper and lower fixed

appliance to close the space and disguise the UR2

as a UR1.

The patient and his parent chose option number (II).

Treatment progressAfter acquiring informed consent form the patient and

parent, an upper pre-adjusted fixed appliance 0.02260.028-inch slot with MBT prescription was bonded, with

the exception of the UR1 and UR2, which were bonded

with Roth prescription brackets at a later stage. The

lower arch was bonded at a subsequent visit. In theupper arch, during the first three visits, the UR2 was by-

passed (Figure 5) and then at the fourth visit, it was

bonded with an axially offset-positioned bracket This

particular bracket position with the Roth prescription

aided in increasing the tip expression of the upper right

lateral incisor, which kept its root away from the

impacted incisor to reduce the risk of root resorption.

In the upper arch, a light nickel–titanium push coil

was used on 0.016 and 0.018-inch stainless steel

archwires to create sufficient space for the unerupted

UR1 (Figure 6). The required space was achieved by

6 months and maintained with an acrylic tooth attached

to an orthodontic bracket to camouflage the space

(Figure 7). This was followed by radiographic consulta-tion to exclude any potential resorption and/or anky-

losis. Accordingly, a sectional CBCT scan for the

maxillary region was recommended for detailed assess-

ment of the anterior teeth. The CBCT provided a more

refined depiction of the UR1 ectopia, illustrating its

rotation and close proximity to the thin cortical plate,

with its apex located within the anterior portion of the

nasal septum with a mild degree of vestibular rootangulation. There was no resorption of the adjacent

teeth, follicular expansion, periapical pathology internal

root resorption or ankyloses (Figure 8).

The DICOM file of the CBCT scan was converted to

an STL file, which was used to print a three-dimensional

model of the maxillary region. This model assisted intailoring the future mechanics that were required to

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Figure 3 Pre-treatment orthopantograph

Figure 4 Pre-treatment cephalometric radiograph: (a) cephalometric radiograph; (b) tracing

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JO Month 2014 Clinical Section A novel approach for impacted incisors 3

align the impacted tooth. Additionally, it helped the oral

surgeon with surgical planning. It was used by the dental

technician to construct the precision attachment and

aided with informed consent of the second phase of

treatment. The laboratory procedure to construct this

attachment involved using the plastic tubes cut into

three equal sized pieces, waxed together in a horizontal

parallel arrangement and attached to the wax pattern of

the attachment. The wax pattern was then sprued, invested

using a carbon-free phosphate bonding investment and

cast using yellow gold alloy (type 4, gold content of 72%,

melting range of 1090–1140uC). The pattern was then

divested, sandblasted using 50-mm aluminium oxide,

trimmed, highly polished and autoclaved for sterilisation

(Figure 9). The laboratory cost for constructing this

precision attachment was around £70.

Next, surgical exposure and bonding of the precision

attachment under intravenous sedation was performed

with the precision gold pad attachment bonded using

dual cure resin bonding material (Figure 10).

On review, the patient reported an uneventful recovery

and orthodontic treatment was started. Orthodontic

mechanics involved a combination of two couple forces

generated by power chain elastic that extended from the eyelet

of a horizontal auxiliary arm welded to the working archwire

and passed through the horizontal tube of the precision

attachment. The auxiliary arm was made from 0.01960.025-

inch stainless steel wire, welded using a CO2 laser. It

extended palatally at a tangent to the incisive papillae.

Night-time anterior box elastics (3/8-inch, 3.5 ounce) were

prescribed to control the overbite (Figure 11). As a result

of these mechanics, the impacted tooth was completely

derotated, while partially erupted, moved palatally and

erupted within the attached palatal tissue in three visits.

Subsequently, an UR1 bracket with reduced torque

(Roth prescription) was bonded and a piggy-back

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Figure 5 Upper fixed appliance, 0.016-inch stainless steel archwire and light NiTi compression spring in place(note: the UR2 is not bonded)

Figure 6 Upper and lower fixed appliance (fully bonded), 0.018-inch stainless steel archwires and light NiTicompression spring in place

Figure 7 (a) At the end of space-opening with 0.01960.025-inch stainless steel customized and coordinated

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4 Almuzian et al. Clinical Section JO Month 2014

technique used, consisting of a base arch wire of

0.01960.025-inch stainless steel, with a vertical step to

avoid interference with tooth alignment and an auxiliary

archwire of 0.012-inch nickel–titanium. Night-time

anterior box elastics (3/8-inch, 3.5 ounce) were used

simultaneously (Figure 12). These mechanics were

carried out for 3 months with regular monitoring of

the tooth and gingival condition.

The final bracket position was reassessed, repositioned

and 0.01960.025-inch nickel–titanium archwire placed

in conjunction with night-time use of two lateral box

elastic (3/8-inch, 3.5 ounce) whilst the closure of resi-

dual spacing was carried out on a 0.01960.025-inch

stainless steel using power chain elastic (Figure 13).

After complete space closure, a 0.01960.025-inch TMA

archwire, for detailing and finishing, was placed in

addition to settling elastics at night time (Figure 14).

The patient was then debonded and fitted with an

upper bonded retainer on the four incisors. Upper

and lower vacuum-formed retainers were provided for

nocturnal use. A localized gingivectomy of the excess

gingivae of the UR1 was performed at debond using

electro-surgical cautery (Figure 15). Fixed appliance

treatment was completed in nineteen months. At review

visit, 2 months later, the patient presented with the

wound healed and gingivitis resolved (Figure 16).

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Figure 8 CBCT of the maxillary region using i-Cat vision #. Top row of serial CBCT slices shows a crown-rootdilaceration and an apical third vestibular root angulation in relation to the root deflecting off the cortical boneof the floor of the nose during final root development

Figure 9 Completed precision attachment on a three-dimensional model of the maxillary region

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JO Month 2014 Clinical Section A novel approach for impacted incisors 5

DiscussionEarly identification of ectopic central incisors, their

position and the degree of displacement are essential for

successful outcome (Macleod and Heath, 2008; Becker

et al., 2010). An impacted incisor with a thin cortical

bone or bone dehiscence has a high potential for

gingival recession (Vandenberghe et al., 2007) and

subsequent aesthetic and hypersensitivity problems(Noar and Gaukroger, 2000).

In this case, the precision attachment and the

information derived from the CBCT scan helped in

identifying the clinical condition of the impacted tooth

and adjacent teeth (Hodges et al., 2013) alongside

designing the precision bonded incisor tip attachment

and planning the orthodontic movement. The mechanics

used in this case allowed the tooth to move and erupt

within the attached palatal gingivae and prevented labial

eruption of the tooth that showed some degree of

vestibular root angulations. These had been reported to

be associated with bone fenestration, gingival recession

(Topouzelis et al., 2010) and even loss of vitality due

to apex perforation of the labial plate of bone (Uematsu

et al., 2004). This would have been difficult or

impossible to achieve using conventional attachments,

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Figure 10 Surgical procedure to expose the impacted UR1 and bond the precision attachment

Figure 11 Mechanics used to derotate the impacted UR1

Figure 12 Mechanics used to align and erupt the impacted UR1

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6 Almuzian et al. Clinical Section JO Month 2014

which lack rigidity, particularly in the axial and antero-

posterior planes.

Additionally, this technique preserved the labial

cortical bone as a minimal amount of clinical crown

was sufficient to provide retention for the precision

attachment which was replaced, when the severity and

depth of impaction had reduced, with a labial bracket

without the need for another surgical exposure. The

second surgical exposure was avoided which might be

required if a single exposure to place an initial labial

bracket from the outset otherwise be undertaken (Lin,

1999; Pavlidis et al., 2011).

At the same time, the tooth was fully derotated while

partially erupted. A gold cast attachment was used for

its biocompatibility and the potential increased success

of bonding due to the increased retentive surface area.

Additionally, the information extracted from CBCT

data helped in assessing the amount of space available

for the unerupted tooth. An additional factor, which

plays a crucial part in the management of impacted

incisors, is the position of the tooth axially, as this has a

significant effect on the stability of the result (Swanson

et al., 1975). A histological observational study by

Reitan found that the teeth with sever rotation show a

significant risk of relapse due to the influence of

free gingival fibre (Reitan, 1967). Another study has

suggested that pre-treatment irregularity and/or rota-

tion of maxillary incisors is a significant risk factor for

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Figure 13 Pre-finishing stage of the treatment

Figure 14 Finishing stage with settling elastic in use

Figure 15 Immediately post-debond and retainer in use

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JO Month 2014 Clinical Section A novel approach for impacted incisors 7

post-retention relapse (Surbeck et al., 1998). Many

options have been advocated to improve the stability

and prevent relapse of rotated teeth, among these are

overcorrection, circumferential supercrestal fibrotomy

(Edwards, 1988), extraction of severely rotated teeth,interproximal enamel stripping (Peck and Peck, 1972;

Tuverson, 1980) or early derotation (Furstman and

Bernick, 1972; Scracter and Bernick, 1976). An experi-

mental study stated that transeptal fibres developed only

when the amelo-cemental junction of the developing

teeth has erupted to the height of the alveolar bone

(Kusters et al., 1991). The orthodontic mechanics used

in this case allowed early derotation, before the trans-septal fibers were fully developed thereby diminishing

the amount of relapse and improving stability. The

relevance of using an anterior maxillary palatal bonded

retainer to also controls the potential vertical relapse of

the apically positioned disimpacted incisor tooth.

It is worth mentioning that the aim of the hybrid

appliance prescription (MBT and Roth prescription) in

this case was to control the excessive proclination of the

impacted tooth after its eruption, which might be

associated with potential gingival recession. However,

offset positioning of a bracket with the solo-prescription

could have controlled this without the disadvantages of

a multiple system. Another patient-related factor to be

considered is the aesthetic requirement during space

creation and tooth alignment. It would be difficult to

have the temporary tooth replacement at the same stage

as conventional gold chain/tooth exposure and align-

ment as the prosthetic tooth might interfere.

Finally, a potential disadvantage of this approach is

the cost of the precision attachment, which is more

expensive than conventional attachments currently used,

as well as the feasibility of using this technology in all

clinical environments.

AcknowledgementsI would like to thank Mr. Philip Benington and Dr.

Anas Al-Mukhtar for their advice in designing the

precision attachment.

Disclaimer statementsContributors All four authors contributed to the article.

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Figure 16 Three-month review showing healing of the gingivae following gingivectomy

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8 Almuzian et al. Clinical Section JO Month 2014

Funding None.

Conflicts of interest None.

Ethics approval None.;

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JO Month 2014 Clinical Section A novel approach for impacted incisors 9

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