Introduction

A Bolton's ratio discrepancy and congenitally missing permanent teeth are common clinical findings in patients seeking orthodontic therapy.13 

The goal of active orthodontic treatment is to consolidate and restore the lost space and replace the missing teeth using either a Maryland bridge or a removable retainer with a pontic or with an implant-retained prosthesis. Drawbacks of a Maryland bridge include inevitable permanent damage of the adjacent natural tooth structures and that it does not accommodate transverse dimensional changes of the dentition. A removable partial denture with a pontic has its own disadvantages in the form of excessive masticatory stress distribution on the supporting adjacent permanent teeth and a compromised esthetic result. The ideal treatment option is the use of an implant-retained prosthesis for the replacement of the missing tooth at the end of orthodontic treatment.4,5  However, this interdisciplinary treatment approach at the end of the orthodontic treatment can sometimes be cumbersome and costly to the patient, requiring visits to various clinics, which might delay completion of orthodontic treatment. This article describes the use of a self-drilling one-piece orthodontic miniscrew as a temporary abutment for the replacement of the congenitally missing right lateral incisor. Advantages include the ease of placement for the orthodontist using closed method6  as they are not formally trained and equipped for the placement of implant-retained prosthesis. In addition, an orthodontic mini-implant temporary crown can serve as a permanent dental restoration for a growing child if the mini-implant is well maintained throughout his or her growth period without significant changes of skeletal morphology.79 

Case Description

A 16-year-old girl came to our office with a chief complaint of excessive spacing of teeth in the upper jaw. The patient wished to have all spaces closed and to have an esthetic smile.

Clinical examination reflected a moderately straight profile, competent lips, normal mentolabial sulcus, and lower facial height.

Intraoral examination revealed (Figure 1) Class I molar and Class I canine relationships on the left and right sides. There was an overjet of 1.5 mm and an overbite of 3 mm with excessive spacing in the upper and lower anteriors. The patient had a congenitally missing right lateral incisor on the orthopantomogram (Figure 2). In addition, the upper left lateral incisor and both maxillary canines were smaller in size.

Figures 1 and 2.

Figure 1. Pretreatment photographs, intraoral. Figure 2. Pretreatment radiographs, orthopantomogram.

Figures 1 and 2.

Figure 1. Pretreatment photographs, intraoral. Figure 2. Pretreatment radiographs, orthopantomogram.

The treatment objectives were to orthodontically consolidate the spaces in the upper and the lower arches, dentally restore the ideal mesiodistal width of the maxillary canines and lateral incisors,10  and reestablish the space loss of the maxillary right lateral incisor for future replacement. The recommended treatment plan was discussed with the patient and the parents.

Roth prescription .022-inch brackets (American Orthodontic) were bonded in both arches. After orthodontic consolidation of spaces, a Class I molar and canine relationship was established with an ideal overjet of 2 mm and an overbite of 2 mm (Figure 3). Adequate space was left mesial and distal to the left lateral incisor, mesial to the left canine, and mesial to the right canine in order to accommodate composite buildups and enhance the dental esthetics. Caution was taken while building up the right canine, and a space equal to the mesiodistal width of the left lateral incisor was maintained for future replacement of the right lateral incisor (Figure 4).

Figures 3 and 4.

Figure 3. Predebonding intraoral before composite buildup. Figure 4. Predebonding intraoral after composite buildup and placement of micro-implant.

Figures 3 and 4.

Figure 3. Predebonding intraoral before composite buildup. Figure 4. Predebonding intraoral after composite buildup and placement of micro-implant.

The patient was informed of the treatment options for replacement of the right lateral incisor along with the advantages and disadvantages of all modalities. Those options included a removable partial denture/a Maryland bridge and an implant-retained prosthesis. It was agreed that implant-retained prosthesis was the ideally suited treatment option for replacement of the missing tooth. However, considering the patient's young age and anticipated residual growth potential, an implant-retained prosthesis was not recommended until her general growth was complete. Hence, after parental consent, an orthodontic mini-implant–supported temporary restoration was recommended for the patient to satisfy her esthetic concerns until her general growth was complete in the next 1½ years.

After the buildup of the left lateral incisor and canines was accomplished, a titanium miniscrew (AbsoAnchor, 1.4 mm diameter × 10 mm) was inserted in the maxillary alveolus of the right lateral incisor (Figures 4 and 5).

Figures 5–10.

Figure 5. Close-up view of orthodontic miniscrew post debonding. Figure 6. Model portraying blocked out undercuts of miniscrew. Figure 7. Post treatment with temporary crown (intraoral). Figure 8. Posttreatment orthopantomogram with crown. Figure 9. Extraoral depicting esthetic smile. Figure 10. Periapical radiograph demonstrating no bone loss at 12 months.

Figures 5–10.

Figure 5. Close-up view of orthodontic miniscrew post debonding. Figure 6. Model portraying blocked out undercuts of miniscrew. Figure 7. Post treatment with temporary crown (intraoral). Figure 8. Posttreatment orthopantomogram with crown. Figure 9. Extraoral depicting esthetic smile. Figure 10. Periapical radiograph demonstrating no bone loss at 12 months.

As we had used a single-piece micro-implant, the undercuts on the head of the micro-implant were blocked out (Figure 6), and a rubber-based impression of the implant and the dentition was taken and sent to the laboratory for fabrication of a porcelain fused to metal (PFM) crown. A PFM crown was cemented using glass ionomer luting cement (GIC, glass ionomer luting and lining) (Figure 7).

The patient was kept on a regular recall schedule for 12 months, and no incidence of implant mobility was noted (Figure 8). She was instructed to maintain oral hygiene around the implant-retained prosthesis using an interdental brush and mouthwash. The patient was happy and satisfied with the facial esthetics achieved at the end of treatment (Figure 9).

Discussion

An implant-retained prosthesis is the treatment of choice for permanent restoration of an edentulous area.1116  However, an implant-retained prosthesis involves high cost, a multi-disciplinary approach, and additional visits to various clinics, which are time-consuming and lead to a delay in completion of the entire orthodontic therapy.

Micro-implants used to retain a temporary crown restoration in order to replace a single missing tooth can be a more ideal treatment option than a removable partial denture or a Maryland bridge as described by Graham.17  The miniscrew stimulates the alveolar ridge and thus helps prevent ridge atrophy, and it prevents the adjacent roots from drifting into the edentulous space.18  According to Chen and colleagues,19  the critical factors for success of orthodontic miniscrews are initial mechanical stability and bone quality and quantity. The closed method does not require an incision for periodontal flap surgery, which is an added advantage and is indicated when full width of alveolar bone is intact on palpation.6  No alveolar bone loss around the implant was observed for 12 months during the recall visits (Figure 10).

Most of the single-piece implants do not have surface treatment, which does not allow osseointegration between the mini-implant and the bone. Hence, the implant can be easily removed at the end of skeletal growth and replaced with the prosthetic dental implant.2022  It is understood that a micro-implant for temporary crown restoration is recommended to temporarily satisfy the esthetic needs of the patient and can be used as a space maintainer option until the general growth of the patient is complete and the patient is monetarily ready to undergo further restorative treatment. The parents must be informed that their child would need to have a final implant-retained prosthesis upon completion of final growth.23,24 

According to Lim and colleagues,25  any treatment plan involving anchorage from miniscrews should consider the possibility of failure, since their initial stability cannot be guaranteed or predicted. Nevertheless, a single-piece micro-implant can be used as a temporary treatment option in order to retain edentulous space after active orthodontic treatment until an implant-retained prosthesis is made.

Abbreviation

     
  • PFM

    porcelain fused to metal

References

References
1
Eustaquio
A
,
Marcelo
S.
Bolton anterior tooth size discrepancies among different malocclusion groups
.
Angle Orthod
.
2003
;
73
:
307
313
.
2
Othman
A
,
Harradine
N.
Tooth-size discrepancy and Bolton's ratios: a literature review
.
J Orthod
.
2006
;
33
:
45
51
.
3
Sıddık
M
,
Faruk
A
,
Metin
N
,
Bülent
C.
Maxillary and mandibular mesiodistal tooth sizes among different malocclusions in a sample of the Turkish population
.
Eur J Orthod
.
2011
;
33
:
592
596
.
4
Brånemark
PI.
Osseointegration and its experimental background
.
J Prosthet Dent
.
1983
;
50
:
399
410
.
5
Vigolo
P
,
Givani
A.
Clinical evaluation of single-tooth mini-implant restorations: a five-year retrospective study
.
J Prosthet Dent
.
2000
;
84
:
50
54
.
6
Turkyilmaz
I
,
Suarez
JC.
An alternative method for flapless implant placement and an immediate provisional crown: a case report
.
J Contemp Dent Pract
.
2009
;
10
:
89
95
.
7
Cronin
RJ
Jr,
Oesterle
LJ.
Implant use in growing patients. Treatment planning concerns
.
Dent Clin North Am
.
1998
;
42
:
1
34
.
8
Rodd
HD
,
Malhotra
R
,
O'Brien
CH
,
Elcock
C
,
Davidson
LE
,
North
S.
Change in supporting tissue following loss of a permanent maxillary incisor in children
.
Dent Traumatol
.
2007
;
23
:
328
332
.
9
Oesterle
LJ
,
Cronin
RJ
Jr,
Ranly
DM.
Maxillary implants and the growing patient
.
Int J Oral Maxillofac Implants
.
1993
;
8
:
377
387
.
10
Müssig
E
,
Lux
CJ
,
Staehle
HJ
,
Stellzig-Eisenhauer
A
,
Komposch
G.
Applications for direct composite restorations in orthodontics [in English, German]
.
J Orofac Orthop
.
2004
;
65
:
164
179
.
11
Leopardi
A.
Single-Tooth Replacement in the Esthetic Zone: Treatment Outcome Perspective
.
Kerr University Online Learning Center, Dental Aegis Continuing Education
.
12
Sailer
I
,
Zembic
A
,
Jung
RE
,
Hämmerle
CH
,
Mattiola
A.
Single-tooth implant reconstructions: esthetic factors influencing the decision between titanium and zirconia abutments in anterior regions
.
Eur J Esthet Dent
.
2007
;
2
:
296
310
.
13
Blatz
MB
,
Bergler
M
,
Holst
S
,
Block
MS.
Zirconia abutments for single-tooth implants—rationale and clinical guidelines
.
J Oral Maxillofac Surg
.
2009
;
67
:
74
81
.
14
Walton
TR.
Changes in the outcome of metal-ceramic tooth-supported single crowns and FDPs following the introduction of osseointegrated implant dentistry into a prosthodontic practice
.
Int J Prosthodont
.
2009
;
22
:
260
267
.
15
Chee
WW
,
Nowzari
H
,
Kaneko
L.
Esthetic replacement of the anterior tooth with an implant-supported restoration
.
J Calif Dent Assoc
.
1997
;
25
:
860
865
.
16
Gibbard
LL
,
Zarb
G. A
5-year prospective study of implant-supported single-tooth replacements
.
J Can Dent Assoc
.
2002
;
68
:
110
116
.
17
Graham
JW.
Temporary replacement of maxillary lateral incisors with miniscrews and bonded pontics
.
J Clin Orthod
.
2007
;
41
:
321
325
.
18
Melsen
B.
What influence has skeletal anchorage had on orthodontics?
In
:
McNamara
JA
Jr,
ed
.
Microimplants as Temporary Orthodontic Anchorage. Craniofacial Growth Series
.
Vol
45
.
Ann Arbor, Mich
:
University of Michigan Center for Human Growth and Development
;
2008
:
15
19
.
19
Chen
Y
,
Kyung
H
,
Zhao
W
,
Yu
W.
Critical factors for the success of orthodontic mini-implants: a systematic review
.
Am J Orthod
.
2009
;
135
:
284
291
.
20
Seo
W
,
Kim
SH
,
Chung
KR
,
Nelson
G.
A pilot study of the osseointegration potential of a surface-treated mini-implant: bone contact of implants retrieved from patients
.
World J Orthod
.
2009
;
103
:
202
210
.
21
Kim
SH
,
Cho
JH
,
Chung
KR
,
Kook
YA
,
Nelson
G.
Removal torque values of surface-treated mini-implants after loading
.
Am J Orthod Dentofacial Orthop
.
2008
;
134
:
36
43
.
22
Kim
SH
,
Choi
JH
,
Chung
KR
,
Nelson
G.
Do sand blasted with large grit and acid etched surface treated mini-implants remain stationary under orthodontic forces?
Angle Orthod
.
2012
;
82
:
304
312
.
23
Tuna
SH
,
Keyf
F
,
Pekkan
G.
The single-tooth implant treatment of congenitally missing maxillary lateral incisors using angled abutments: a clinical report
.
Dent Res J (Isfahan)
.
2009
;
6
:
93
98
.
24
Koka
S.
Is an implant-supported restoration better than a fixed partial denture to replace single missing teeth?
Compend Contin Educ Dent
.
2006
;
27
:
156
,
158
161
.
25
Lim
HJ
,
Eun
CS
,
Cho
JH
,
Lee
KH
,
Hwang
HS.
Factors associated with initial stability of miniscrews for orthodontic treatment
.
Am J Orthod Dentofacial Orthop
.
2009
;
136
:
236
242
.