Management of Upper Incisors Agenesis – Space Closure. A Case Report

CliniCAl CAse

Paulina Trześniewska

_{, Joanna Antoszewska}

Management of Upper Incisors Agenesis – Space Closure.

A Case Report

Postępowanie w przypadku hipodoncji bocznych zębów siecznych szczęki

– zamykanie przestrzeni. Opis przypadku

Department of Dentofacial Orthopedics and Orthodontics, Wroclaw Medical University, Poland A – concept; B – data collection; C – statistics; D – data interpretation; E – writing/editing the text; F – compiling the bibliography

Abstract

lateral incisors’ hypodontia may be successfully treated by orthodontic space closure with canines substitution or space opening with prosthetic replacements. Authors describe a hypodontia case of both upper lateral incisors with Class i malocclusion. The orthodontic treatment of a young patient consisted of space closure with canines substitution and lateral upper teeth mesialization with the use of mini-screw implant (Msi). Proper occlusion alongside a fine aesthetic effect without necessitating further prosthodontic restoration was obtained (Dent. Med. Probl. 2013, 50, 2, 244–248).

Key words: orthodontics, hypodontia.

Streszczenie

Hipodoncja górnych zębów siecznych bocznych może być z powodzeniem leczona przez ortodontyczne zamknięcie luk po brakujących zębach z ustawieniem kłów górnych w miejscu zębów siecznych bocznych bądź przez odtwo-rzenie przestrzeni z następującą odbudową protetyczną. Autorki opisują przypadek pacjentki z hipodoncją bocz-nych zębów sieczbocz-nych górbocz-nych ze współwystępującą wadą zgryzu klasy i. leczenie ortodontyczne młodej dziew-czyny polegało na zamknięciu luk po brakujących zębach z mezjalizacją kłów górnych i zębów bocznych szczęki z zastosowaniem miniśruby ortodontycznej (Msi). Po zakończonej terapii uzyskano dobrą okluzję i korzystny efekt estetyczny bez konieczności zastosowania uzupełnień protetycznych (Dent. Med. Probl. 2013, 50, 2, 244–248). Słowa klucze: ortodoncja, hipodoncja.

Dent. Med. Probl. 2013, 50, 2, 244–248

issn 1644-387X © Copyright by Wroclaw Medical University and Polish Dental society

The prevalence of tooth agenesis is estimat-ed from 2.4% to 6.7% of the population, excluding third molars [1, 2]. in the study of González-Allo et al. [3] and Cantekin K et al. [4] the higher rate of hypodontia was found in females than in males, but those results were of statistic significance.

Most frequently, agenesis affects maxillary lat-eral incisors, second premolars and mandibular incisors [5]. including third molars, the percent-age of hypodontia reaches circa 30% of the popu-lation [2]. An english investigation showing a sta-tistically significant delay of the dental age among patients displaying tooth agenesis with

associa-tion of the severity of the hypodontia and the de-lay might be interesting for treatment and orth-odontic planning [6]. Also chemotherapy in young children may be associated with microdontia and hypodontia of the lateral teeth [7]. On the other hand, there is an alarming investigation from the University of Pittsburgh revealing a correlation between hypodontia and cancers (due to a com-mon molecular pathway) [8].

The patients with hypodontia require mul-tidisciplinary treatment [9, 10]. Generally, there are two options for the patients with lateral inci-sor agenesis: space closure or prosthetic

replace-Fig. 1. Pretreatment extraoral view: a) en face, b) en face – smile, c) profile

Ryc. 1. Widok zewnątrzustny przed leczeniem: a) en face, b) en face – uśmiech, c) profil

or dental implants are used to restore missing den-tition [14, 15]. Despite the orthodontist and the pa-tient’s personal preferences, the type of malocclu-sion, the patient’s profile, crowding and morphol-ogy of the upper canines play an important role in treatment planning [12, 16]. Currently, the pos-sibility of utilizing mini-screw implants (Msis) gives therapists a new treatment option, providing the skeletal anchorage for tooth movement previ-ously difficult or even impossible [17, 18].

Case Report

Patient A. M. 14 year old presented for orth-odontic treatment with a major complaint: an un-attractive smile. Objective extraoral examination revealed facial symmetry, increased naso-labial angle and slightly retruded chin (Fig. 1). intraoral examination, verified by an orthopantomogram, showed the upper lateral incisors hypodontia.

The upper canines were rather small and of a light shade (Fig. 2). The proposed treatment approach included upper fixed orthodontic appliance and one Msi in the anterior area to support the skele-tal anchorage.

Proper brackets positioning allowed improve-ment of the overbite and overjet after the aligning phase of the treatment (Fig. 3a, b). After closing the spaces in the anterior region and mesializa-tion of the upper canines, a Msi 6 mm long (Or-tho easy®_{-pin FOResTADenT, Pforzheim,}

Ger-many) was inserted above the roots of the upper central incisors. After insertion the mini-screw implant was immediately connected with the an-terior teeth thus producing anchorage for the pos-terior teeth mesialization (Fig. 3c). During treat-ment, the upper canines where recontoured to re-semble the upper lateral incisors. The first upper premolars were mesially rotated, achieving bet-ter inbet-terdigitation with the lower teeth. Afbet-ter the treatment, normal overbite and overjet, space

clo-a) b) c)

Fig. 2. Pretreatment intraoral view: a) left side, b) en face, c) right side

Ryc. 2. Warunki zgryzowe przed leczeniem: a) strona lewa, b) en face, c) strona prawa

sure by mesialization of the upper teeth, Class ii on molars without the further necessity of the prosthodontic restoration (Fig. 4), as well as aes-thetic facial features (Fig. 5) were obtained.

Discussion

Treatment planning is always crucial in orth-odontic therapy. Decisions whether to close the spaces after congenitally missing lateral incisors or to substitute canines should be made very care-fully with understanding the limitations and long-term consequences of the different treatment op-tions. Opening the spaces always requires

pros-thetic replacements with the dental implants or tooth supported restorations, which should be precisely explained to the patient and their fam-ily. Conventional bridges do not seem to be a vi-able option in young patients due to the necessity of the tooth preparation. Bonded bridges may be an interesting alternative, leading to good aesthet-ic effects [14]. However long-term observations of Williams et al. [19] showed a relatively high risk of debonding. Finally, treatment with the sin-gle implants – a frequently described method of one-tooth replacement should be mentioned [15]. Many investigations showed that more than 90% of the patients are satisfied with the effects of im-plant supported single tooth restoration in the

Fig. 3. intraoral view: a) before treatment, b) after levelling phase, c) after Msi insertion

Ryc. 3. Zdjęcia wewnątrzustne: a) przed leczeniem, b) po uszeregowaniu zębów, c) po umieszczeniu miniśruby

a) b) c)

Fig. 4. Posttreatment intraoral view: a) left side, b) en face, c) right side

Ryc. 4. Warunki zgryzowe po leczeniu: a) strona lewa, b) en face, c) strona prawa

a) b) c)

Fig. 5. Posttreatment extraoral view: a) en face, b) en face – smile, c) profile Ryc. 5. Widok zewnątrzustny po leczeniu: a) en face, b) en face – uśmiech, c) profil

al bone loss around the adjacent teeth, connect-ed with a larger loss and rconnect-eduction of the distance between the implant and the tooth were men-tioned in contemporary literature [22]. A swed-ish article regarding implant insertion in the aes-thetic zone showed other unfavorable aspects: at-rophy of the distal papillas, increased frequency of bleeding or mucositis when compared to the con-tralateral natural teeth [20]. Discoloration of the mucosa around the fixed prosthodontic replace-ments was found in more than 50% of the treated patients [21]. iseri and solow [23] examined radio-grams of the patients aged 9–25 years and proved continuous eruption of the natural teeth, which al-lowed the conclusion that dental implants should not be used in childhood, adolescence or young adulthood. This observation showed the need for temporary reconstruction of the spaces opened for the prosthodontic restorations in the young pa-tients. some of the disadvantages of single-tooth replacements with the dental implants may be re-duced by proper orthodontic treatment with the gaining of adequate space for the screws. Also, the correct timing of implant insertion – after com-pleted dental and skeletal development – may lead to an improvement of the results [22]. Better alve-olar bone created by orthodontic movement – ca-nine distalization [24] – or bone grafts may result in a reduction of horizontal resorption [25].

Orthodontic space closure is the further treat-ment option in case of the lateral incisors agen-esis. The greatest advantage of such a method is that there is no requirement for prosthodontic re-construction. However, one important question should be posted: does orthodontic therapy with canine substitution lead to an acceptable aesthetic

tution is a valid therapeutic option, giving satisfy-ing aesthetics. Morphology, width and color of the upper canines serving as the “new lateral incisors”, are the major factors influencing good treatment effects. Brighter than normal and rather small ca-nines are favorable in achieving an attractive smile after closure of the spaces [16]. The substituted ca-nines often need recontouring. Thordarson et al. [26] showed that this procedure is safe and pain-less to the patient.

in the cases of Angle Class i malocclusion the treatment of lateral incisors agenesis may require space opening with the subsequent prosthodontic substitution of the missing teeth or compensative extractions in the lower dental arch [27]. The oth-er method calls for the uppoth-er canine and premo-lar mesialization and opening spaces for the fixed dentures in the posterior region. Moving the spac-es for implants or bridgspac-es laterally, out of the aspac-es- aes-thetic zone is a remarkable benefit of such proto-col [28]. This approach would probably have been used in the presented case if the absolute anchor-age could not be applied. However, the authors uti-lized different treatment options: canine substitu-tion with mesializasubstitu-tion of the lateral upper teeth in the patient with Class i malocclusion. Due to the application of Msi our patient avoided prost-hodontic treatment; the whole dentition forward movement ended up with good and stable occlu-sion.

summing up, usage of absolute anchorage counteracts the undesired distal movement of the anterior teeth during protraction of the lateral ones and allows mesial displacement of the teeth – the movement previously considered difficult or even impossible.

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Address for correspondence:

Paulina Trześniewska

Department of Dentofacial Orthopedics and Orthodontics Wroclaw Medical University

Krakowska 26 50-425 Wrocław Poland Tel.: +48 71 784 02 99 e-mail: paulinatrzesniewska@gmail.com Received: 30.04.2013 Revised: 27.06.2013 Accepted: 1.07.2013

Praca wpłynęła do Redakcji: 30.04.2013 r. Po recenzji: 27.06.2013 r.