Mini-screw Application For Gummy Smile Correction Dişeti

OLGU RAPORU (Case Report)
Hacettepe Dişhekimliği Fakültesi Dergisi
Cilt: 31, Sayı: 3, Sayfa: 44-51, 2007
Mini-screw Application For Gummy Smile
Correction
Dişeti Gülümsemesi Tedavisinde Mini Vida
Uygulaması
*Tülin (Uğur) TANER DDS, PHD, *Soner KAMACI DDS, **Bahadır GİRAY DDS, PhD
* Hacettepe University Faculty of Dentistry Department of Orthodontics
** Hacettepe University Faculty of Dentistry Department of Oral Surgery
ABSTRACT
ÖZET
The patient was a 20-year-old girl who had an Angle
Class II Division 2 malocclusion with a gummy
smile. The treatment involved intrusion of the upper
incisors with mini-screw implants as the orthodontic
anchorage. After treatment, adequate overbite and
overjet and a satisfactory maxillary gingival exposure
in the smile were obtained. The mini-screw implant
anchorage method is useful for correction of gummy
smile in a deep- bite patient.
Hasta, dişeti gülümsemesi problemi ve Angle Sınıf II
bölüm 2 malokluzyonu olan 20 yaşında bir bayandı.
Tedavide ankraj amaçlı olarak kullanılan mini vidalar
yardımıyla üst keser dişler intrüze edildi. Tedavinin
ardından ideal bir overbite ve overjet ve gülümsemede
tatmin edici bir dişeti görünülürlüğü elde edildi.
Mini vida ankraj metodu derin kapanışı ve dişeti
gülümsemesi olan hastaların tedavisinde yararlı bir
yöntemdir.
KEYWORDS
ANAHTAR KELİMELER
Derin kapanış, Mini vida, Dişeti gülümsemesi
Deep bite, Mini-screw, Gummy smile
45
INTRODUCTION
Esthetic judgement is made by viewing the
patient in rest position, normal conversation,
and full smile. 2 mm or more of maxillary gingival exposure while full smiling may be defined as
“gummy” smile1.
In a study of the full smiles of 454 dental and
dental hygiene students aged 20–30 years, Tjan
and Miller2 divided the smile line into three types:
a high smile line, revealing the complete vertical
length of maxillary incisors and a contiguous
band of the gingiva (%11 of this population); an
average smile, revealing 75–100 % of the maxillary incisors (%69 of this population); and a low
smile, revealing less than 75% of the maxillary
incisors (%20 of this population).
The high smile line, defined as gummy smile
commonly provokes strong concern from clinicians3,4. Treatment alternatives of gummy smile
include various combinations of periodontal, surgical and orthodontic therapy.
When the patients have excessive gingival
margins, and short clinical crowns, simple gingivectomy or surgical crown lengthening with
removal of crestal alveolar bone procedures are
indicated5,6,7. However, periodontal procedures are not enough for the correction of severe
gummy smile. In openbite cases with severe vertical maxillary excess, maxillary superior repositioning by Le Fort I osteotomy is generally the
treatment of choice4.
In this case report, intrusion of maxillary incisors and elimination of gummy smile using two
mini-screws implants in an adult female patient
is demonstrated.
Case presentation
A 20-year-old female patient was referred to
our clinic for orthodontic treatment. Her chief
complaint was an excessive overbite and gummy
smile. Her medical history was not contributory.
The patient exhibited a straight facial profile
with a slightly prominent upper lip. Maxillary gingival exposure in the smile or a “gummy smile”
was noted (Figure 1A-C). Intraoral photographs
showed complete overlapping of mandibular incisors by extruded maxillary incisors. Molar and
canine relationship was Class I on the right side
and Class II on the left side. The mandibular midline shifted 2 mm to the left side relative to the
maxillary and facial midlines. The arch length
discrepancy was -1.5 mm for the upper and lower
dental arches. The upper central incisors and canines had mesial-in rotations (Figure 2A-E).
Panoramic radiographs revealed no missing
teeth except the upper and lower right third molars. These teeth were extracted before the orthodontic treatment. The lower first molars were
restorated with fillings (Figure 3).
Orthodontic intrusion of maxillary anterior
teeth may eliminate the gummy smile in deepbite cases to some degree. Orthodontic tooth
movement has always been limited because of
insufficient anchorage control8. Conventional
orthodontic methods require complex intraoral
appliances or extraoral appliances to reinforce
anchorage9,10. Effective intrusion of maxillary anterior teeth is not always possible with intraoral
anchorage systems and extraoral appliances rely
on excellent patient compliance.
Intraosseous anchorage systems do not require patient cooperation while obtaining pure intrusion11-14. Among various intraosseous anchorage implants, mini-screws have the advantages
of simpler insertion and immediate loading.
A
FIGURE 1 A
Pre-treatment extraoral facial photograph
46
B
B
FIGURE 1 B
(B) Pre-treatment extraoral lateral photograph
C
C
FIGURE 1 C
(C) Pre-treatment smiling photograph
D
E
A
FIGURE 2 A-E
FIGURE 2 A-E
(A-E) Pre-treatment intraoral photographs
(A-E) Pre-treatment intraoral photographs
47
TABLE I
Pretreatment and postreatment cephalometric measurements
Pretreatment
Postreatment
SNA(o)
81
80
SNB(o)
76
76
ANB(o)
5
4
FMA(o)
23
24
FIGURE 3
U1-SN(o)
94
91
Pre-treatment panoramic radiograph
U1-FH(o)
108
104
L1-MP(o)
81
94
Overbite(mm)
8 mm
2 mm
Overjet(mm)
6 mm
2 mm
Upper Lip to E-Line(mm)
-2 mm
-4 mm
Lower Lip to E-Line(mm)
-2 mm
-4 mm
Lateral cephalometric analysis (Figure 4)
showed a skeletal Class 2 Division 2 relationship, mandibular retrusion and slightly decreased
mandibular plane angle (FMA angle: 23o).
The upper incisors inclined palatally at a 94o
angle relative to the SN plane (U1-SN) and 108o
angle relative to FH plane (U1-FH), and the lower
incisors inclined lingually at an 81o angle relative
to the mandibular plane (L1-MP) and a 76o angle relative to the FH plane (L1-FH). The positions of the upper incisors were extruded relative
to the upper lip and functional occlusal plane.
Overbite was 8 mm and overjet was 6 mm. The
upper and lower lips both were -2 mm relative to
the E-line (Figure 4, Table I).
A temporomandibular joint evaluation showed
no signs of clicks or crepitation, and the facial
and masticatory muscles were asymptomatic.
Treatment objectives
The treatment objectives included (1) intruding
the upper incisors with mini-screw impants as
the orthodontic anchorage (2) obtaining adequate overbite and overjet for a satisfactory maxillary
gingival exposure in the smile and (3) obtaining
Class I molar and canine relationships.
Treatment
FIGURE 4
Pre-treatment lateral cephalometric tracing
Treatment started with a .016X.016 inch NiTi
utility arch for alignment and leveling of upper incisors. After that, a segmental .016X.022 stainless
steel (SS) archwire was fitted to the upper incisors
with a surgical spur at the midpoint of the central
incisors. Another day, two mini-screw implants
were implanted in the alveolar bone between the
roots of the central and lateral incisors bilaterally
under local anesthesia. At the same appointment,
an 18-mm-sentalloy coil-spring was placed from
the implants to the surgical hook (Figure 5). Upper incisors were intruded with an 80 gr of force
for 5 months. After intrusion of the incisors, a
48
utility arch was inserted and ligated to the implants for enhancing anchorage while aligning and
leveling the posterior teeth with an .016 inch NiTi
piggy-back archwire.
FIGURE 6
After removal of the mini-screw implants
FIGURE 5
Intrusion of the upper incisors
Alignment and leveling of the lower teeth were
accomplished using .016 inch NiTi, .016 SS and
.016X.022 inch SS archwires sequentially. At 12
months of orthodontic treatment, the mini-screw
implants were removed. The removal of miniscrew implants was uneventful (Figure 6). The canine and molar relationships were Class II on the
left side at that time. Prolonged use of Class II
elastics were not effective. Thus, a Eureka Spring
appliance was used to correct the Class II relationship on the left side. Three months after the
insertion of the Eureka Spring, Class I molar and
canine relationship were achieved (Figure 7). Total
treatment time was 28 months. Upper and lower
hawley appliances were worn for retention.
Results
Upper incisors were intruded successfully and
an improvement of the gummy smile could be
observed in a posed smile (Figure 8A-C). Class
I molar and canine relationships were obtained
with adequate amounts of overbite and overjet
(Figure 9A-E).
No root resorption occurred in the intruded
upper incisor region, and root paralelling was
achieved. Lower left third molar was extracted
during orthodontic treatment (Figure 10).
FIGURE 7
Eureka Spring appliance
The post-treatment lateral cephalometric
analysis showed no skeletal changes but changes in incisor inclinations and lip positions. The
maxillary incisor inclination was slightly decreased and the mandibular incisor inclination was
increased to the normal value. An 8 mm of deep
overbite and a 6 mm of overjet was corrrected
to 2 mm (Figure 11). Upper and lower lips were
slightly retracted due to the changes in incisor
positions. The significant intrusion of upper incisors was evident on superimpositions of pre- and
post-treatment cephalometric films (Figure 12).
Discussion
The extruded upper anterior teeth should be
intruded during orthodontic treatment to improve occlusal relationship and obtain balanced
facial esthetic and a beautiful smile. However, in-
49
A
A
FIGURE 8 A
Post-treatment extraoral facial photograph
B
B
FIGURE 8 B
Post-treatment extraoral lateral photograph
C
C
D
FIGURE 8 C
FIGURE 9 A-E
Post-treatment smiling photograph
(A-E) Post-treatment intraoral photographs
50
E
FIGURE 9 A-E
(A-E) Post-treatment intraoral photographs
FIGURE 11
(A-E) Post-treatment intraoral photographs
FIGURE 10
Post-treatment panoramic radiograph
trusion of extruded upper incisors still has many
limitations.
Before deciding to intrude the extruded incisors, correct diagnosis and case selection are essential. The marginal bone level of the upper incisors and the overall periodontal condition must
be considered. The amount of intrusion needed,
the treatment period and the patient’s general
health are other factors to be considered.
When it is performed on nongrowing patients, it is commonly accepted that correction of
deep bite by extrusion of posterior teeth is more
difficult to accomplish and less stable16,17. Therefore, it would be better to intrude incisors to achieve a proper gingival exposure18. In this case,
our evaluation led us to the conclusion that the
deep bite and gummy smile would be improved
by upper incisor intrusion.
Intrusion by conventional orthodontic methods
such as segmental or continuous techniques, usually accompanies extrusion of the anchorage te-
FIGURE 12
Post-treatment panoramic radiograph
eth. Some archwire systems such as utility arch19
or intrusion base arch20 systems are generally used
for incisor intrusion. But these methods create a
force to elongate the molars, based on the law of
action and reaction. Extrusion of the anchorage
molar teeth can cause clockwise rotation of the
mandible, and, as a result retrusion of the chin
can also occur. The J-hook headgear depends on
anchorage on the head and is also used for incisor
intrusion, but it requires excellent patient cooperation21. Our purpose of using mini-screw implants as skeletal anchorage was to totally eliminate
the need for patient compliance and minimize the
side effects to the anchorage teeth.
Regarding the optimum force for intrusion,
Burstone20 suggested 20 g of force for intruding
51
an anterior tooth and Gianelly and Goldman22
recommended 15 to 50 g of force for small teeth.
In this case, an 80 gr of intrusion force was used
on 4 upper incisors and 3 mm of true intrusion15
was obtained without notable root resorption or
vitality problems during the active treatment period.
This case was noncompliant with the use of
Class II elastic wear to correct the Class II molar
relationship on the left side. The advantages of
the Eureka Spring appliance for correction of sagittal tooth relationships have been reported23,24.
In this patient, with the unilateral wear of the
spring, an effective and a rapid correction to
Class I molar relationship was achieved. Eureka
Spring was well tolerated by the patient.
Conclusions
The maxillary incisors achieved remarkable
intrusion and alignment with the miniscrew implant anchorage without relying on patient cooperation. There were no side effects and no problems with patient cooperation. Moreover, there
was no obvious root resorption, either. This case
report demonstrated that the mini-screw implant
anchorage method was useful for achieving an
excellent improvement of a dental deep bite and
gummy smile.
3. Janzen EK. A balanced smile—a most important treatment
objective. Am J Orthod. 1977; 72:359– 372.
4. Peck S, Peck L, Kataja M. The gingival smile line. Angle
Orthod. 1992; 62:91–100.
5. Kokich, V.G.: Esthetics: The orthodontic-periodonticrestorative connection, Semin. Orthod. 2:21-30, 1996
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Acknowledgements
We are indebted to Prof Dr Enacar, whose
treatment principles were guidelines in the treatment of this patient and we mourn his premature
death in May 14, 2004.
19. Ricketts RM, Bench RW, Gugino CF, Hilgers JJ, Schulhof
RJ. Bioprogressive Therapy. Denver, Co: Rocky Mountain
Orthodontics; 1979:111-126
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Orthod. 1977;72:1-22
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incisors in adult patients with marginal bone loss. Am J
Orthod Dentofacial Orthop. 1989;96:232-241
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CORRESPONDING ADDRESS
Tülin (UĞUR) TANER DDS, PhD
Hacettepe University Faculty of Dentistry Department of Orthodontics 06100 Sihhiye-Ankara/TURKEY
Tel: +90 312 305 2290 Fax: +90 312 309 1138 E-mail: tulinortho@gmail.com