Orthodontic treatment of gummy smile by using mini

O n l i n e O n ly
Orthodontic treatment of gummy smile by using
mini-implants (Part I): Treatment of vertical growth
of upper anterior dentoalveolar complex
Tae-Woo Kim*, Benedito Viana Freitas**
Abstract
Orthodontic mini-implants have revolutionized orthodontic anchorage and biomechanics
by making anchorage perfectly stable. In the first part of this study, ‘gummy smile’ was
defined and classified according to its etiologies. Among them, dentoalveolar type, a good
indication for mini-implant treatment, was divided into three categories that will be presented in consecutive articles: a) Cases with vertical growth of upper anterior dentoalveolar complex (Cases 1, 2, 3), b) Cases with protrusion of anterior dentoalveolar complex
(Cases 4, 5), and c) Cases with protrusion of upper anterior dentoalveolar complex and
extrusion of upper posterior teeth (Cases 6, 7). Three cases with excessive vertical growth
of upper anterior dentoalveolar complex will be presented. They were characterized with
extrusion and retroclination of upper incisors, deep overbite, and gummy smile. The aim
of this paper is to show the mini-implant useful at the anterior area to intrude incisors and
gummy smile correction. Upper anterior mini-implant (1.6 x 6.0 mm) and a NiTi closed
coil spring were used to intrude and procline the retroclined extruded incisors. Miniimplants can be used successfully as orthodontic anchorage to intrude anterior teeth.
Keywords: Mini-implants. Intrusion. Gummy smile. Segmented arch.
es depends on the muscle activity. As a general guideline, in adolescents 3 to 4 mm of the
maxillary incisor should be displayed at rest,
and the entire clinical crown (with some gingiva) should be seen on smiling.2 Gummy smile
can be divided in several categories according
to its etiologic factors.3,4
When used as orthodontic anchorage, miniimplants provide orthodontists with a high
INTRODUCTION AND LiteraturE REVIEW
Most of dentists define “gummy smile” as
excess gingival display.1 But if they are asked
to decide whether cases are “gummy smile” or
not, their answers may not be unanimous. It
is not simple to determine if one patient have
gummy smile or not, because patients can
pose their smile. In other words, the amount
of upper incisor and gingival exposure chang-
*Professor and Chairman, Department of Orthodontics, Seoul National University, South Korea.
**Head Professor of the Discipline of Orthodontics, Federal University of Maranhão. Visiting Professor at Seoul National University, South Korea.
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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex
potential for successful results while offering
many different treatment options since they
need not rely on patient compliance. Miniscrews are indicated for tooth intrusion as they
allow practitioners to apply light and continuous forces, which can reduce apical resorption,
often associated with intrusive movement.5,6
Creekmore and Eklund7 reported the use
of a metal implant for the correction of deep
overbite. They placed a vitalium screw below
the anterior nasal spine and stretched an elastic
as far as the upper central incisors. They succeeded in intruding these teeth by 6 mm and
tipped them 25º buccally avoiding infection,
pain or other screw-related complications.
However, the authors considered that it would
be premature to disseminate the use of this
technique. Kanomi8 reported that the intrusion
of lower incisors in a patient with deep overbite was achieved by means of a screw measuring 6 mm in length and 1.2 mm in diameter.
Ohnishi et al9 also showed a clinical case with
deep overbite treated using mini-implants for
intrusion of the upper incisors. Intrusion also
improved the patients’ gingival smile.
The effects of mini-implant intrusive biomechanics are still poorly understood. Currently,
the available literature consists mainly of clinical
case reports and a handful of studies on animals.
The literature clearly shows that teeth can be intruded successfully using mini-screws as anchorage but there is great variability regarding the
amount of intrusion, load time, intrusive forces
and their relation to root resorption, hindering
its clinical application by ortodontists.5,7,10
•
•
•
Short upper lip type
- Short philtrum height.
Skeletal type
- Vertical maxillary excess.
- Maxillary protrusion.
Dentoalveolar type
- Excessive vertical growth and/or
- Protrusion of upper anterior dentoalveolar complex.
This dentoalveolar type is a good indication
of mini-implant treatment. The cases that will
be presented in consecutive articles were classified as follows:
1) Cases with vertical growth of upper anterior dentoalveolar complex (Cases 1, 2, 3).
2) Cases with protrusion of anterior dentoalveolar complex (Cases 4, 5).
3) Cases with protrusion of upper anterior
dentoalveolar complex and extrusion of
upper posterior teeth (Cases 6, 7).
Cases with vertical growth of upper anterior
dentoalveolar complex
Cases with excessive vertical growth of upper
anterior dentoalveolar complex usually show extrusion and retroclination of upper incisors, deep
overbite, and gummy smile (Figure 1).
This kind of case could be treated well with
the Burstone’s Segmented Arch Technique.11 It
would be used “one-piece intrusion arch” for
the retroclinated and extruded upper incisors
(Figure 2). In this technique, high-pull headgear
and precision lingual arch are used to counteract the adverse reactions like extrusion of upper
molars. But the mini-implants mechanics (Figure 3) can treat the retroclined and extruded
incisors very efficiently without an extrusion of
upper molars and it does not need the patient’s
cooperation. This mini-implant technique was
modified from the method reported by Creekmore and Eklund7 (Figure 3).
After placing a 1.6 x 6.0 mm mini-implant
(Jeil Med Co, Seoul, Korea) without drilling,
Etiology and classification
• Dento-gengival type
- Deficient gingival recession, which is revealed by a short clinical crown.
• Muscular type
- Hyperactivity of the elevator muscle of
the upper lip.
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Kim TW, Freitas BV
A
B
C
FigurE 1 - Cases showing excessive vertical growth of upper anterior dentoalveolar complex. A) Case 1 (10y 6m/ male, Class II, div 2).
B) Case 2 (12y, male Class I). C) Case 3 (26y 5m, male/ Class II div. 2).
A
B
FigurE 2 - A) Burstone’s one-piece intrusion arch. B) One-piece intrusion arch is very efficient to intrude and procline the retroclined and extruded incisors without extruding molars.
Case 1 was treated with non-extraction for
two years. His gummy smile and deep overbite
was treated well with a mini-implant (Figure 3,
4A, 5). For accelerating the mandibular growth,
twin-blocks were used. Case 2 was treated with
non-extraction for three years (Figure 6). His
gummy smile and deep overbite was also improved very well with the same mechanics (Figure 3). Case 3 was treated by intrusion of upper
incisors with a mini-implant and by a mandibular advancement surgery (Figure 7).
a NiTi closed coil spring was applied immediately over a 0.019 x 0.025-in stainless steel
box wire (Figure 3). The mini-implant and the
upper portion of NiTi closed coil spring was
covered by a flap. The covered mini-implant
was not discomfort to patients and it was preferred to a headgear and a lingual or transpalatal arch. After using this mechanics, three cases
showed upper incisors that were intruded and
proclined (Figure 3B and 4) as one-piece intrusion arch was used (Figure 2A).
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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex
A
B
B
B
⇑
⇑
C
A
FigurE 3 - A) 1.6 x 6.0 mm mini-implant (Jeil Med. Co., Seoul, Korea) and
NiTi closed coil spring to intrude and procline the retroclined extruded
incisors. B) Intraoral photos of Case 1. C) Upper central incisors intruded
and proclined as one-piece intrusion arch made with 0.019 x 0.025-in stainless steel box wire was used to prevent impingement of gingival tissue.
B
C
FigurE 4 - Superimposition of tracings before treatment and after intrusion and proclination of upper incisors. A) Case 1: After using mini-implant for 6
months (Figure 3). Upper incisors were intruded and proclined like the movement by one-piece intrusion arch (Figure 2). B) Case 2: After 1 year, upper
incisors were intruded and proclined with a lot of growth. C) Case 3: After 1 year and 2 months, this case also showed upper incisors were intruded and
proclined. Mandibular retrognathism was treated by advancement surgery.
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A
A
C
B
C
C
C
D
B
C
D
D
D
D
FigurE 5 - Case 1 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared after debonding. B) Profile was improved by
using Twin-Block. C) Before treatment. D) After debonding.
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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex
A
A
C
B
C
C
C
D
B
C
D
D
D
D
FigurE 6 - Case 2 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared. B) After debonding, his profile had not
changed. C) Before treatment. D) After debonding, this case was also treated with non-extraction.
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A
A
C
B
C
C
C
D
B
C
D
D
D
D
FigurE 7 - Case 3 (In A and B, left = before treatment, right = after treatment). A) Gummy smile disappeared by an intrusion of upper incisors with a miniimplant, which made the superior impaction surgery of maxilla not necessary. B) His retrognathic mandible was improved by mandibular advancement
surgery. C) Before treatment. D) After debonding.
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Orthodontic treatment of gummy smile by using mini-implants (Part I): Treatment of vertical growth of upper anterior dentoalveolar complex
be corrected effectively. This method was first
introduced by Creekmore and Eklund7 and recently reported by Ohnishi et al.9
These patients were treated with a sectional arch on the anterior teeth, which were
connected to a mini-implant inserted between
the incisors by means of a closed NiTi spring.
This procedure provides some advantages such
as no subsequent extrusion, which can lead to
a rotation of the mandible in a clockwise direction, opening the mandibular plane and worsening the patient’s pattern.
DISCUSSION
In the past, molar extrusion was the most
common treatment to correct deep overbite.
However, the intrusion of anterior teeth became possible with the introduction of the sectional arch wire technique by Burstone. However, this method requires patient compliance
in the use of high-pull headgear and other appliances. Lately, mini-implants have been used
for treating of Angle Class II, division 2 malocclusions with deep overbite. This procedure
is simple and does not require patient compliance. Although concrete evidence is still lacking to prove that treatments involving incisor
intrusion are more stable over time, we can
now intrude anterior teeth free from the past
restrictions when molar extrusion was the only
option for treating deep overbite.
With this new treatment, we have succeeded in intruding upper incisors and enhancing
gingival smile using only mini-implants and
sectional arch wires.
Gingival smile can be divided into various
categories according to etiological factors. Dentoalveolar gingival smile occurs due to excessive incisor eruption in relation to the upper
lip. Dentogingival smile is related to abnormal
tooth eruption, gingival hyperplasia or lack
of gingival recession, as evidenced by a short
height crown. Gingival smile of skeletal origin
occurs on account of excessively vertical maxillary growth and requires orthognathic surgery.
A short upper lip is also a frequent cause of gingival smile.3,4 Muscular gingival smile is caused
by overactivity of the upper lip levator muscle.
Finally, gingival smiles can be caused by a combination of these factors.
All patients shown in this article had dentoalveolar gingival smile. Only the central incisors were extruded and the posterior teeth were
in normal position vertically. In this category, if
extruded teeth are intruded, as in such cases,
both the overbite and the gingival smile can
Dental Press J. Orthod.
Conclusion
The use of mini-implants in the anterior region was effective for the intrusion of upper incisors and therefore the gingival smile was corrected in all cases. These intrusion movements
were obtained easily and without patient compliance. Patients did not complained of discomfort caused by the mini-implants. Mini-implants
can be successfully used as anchorage for the
intrusion of anterior teeth.
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Kim TW, Freitas BV
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Submitted: September 2008
Reviewed and accepted: April 2009
Contact address
Benedito Viana Freitas
Avenida da Universidade, qd. 2, nº 27 - Cohafuma
CEP: 65070-650 - São Luís / MA
E-mail: beneditovfreitas@uol.com.br
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