Orthodontic and Surgical Management of Impacted Teeth

Orthodontic and Surgical Management of

IMPACTED
TEETH

Vincent G. Kokich, DDS, MSD

Affiliate Professor
Department of Orthodontics
University of Washington School of Dentistry
Seattle, Washington

David P. Mathews, DDS

Affiliate Associate Professor
Department of Periodontics
University of Washington School of Dentistry
Seattle, Washington
Private practice
Tacoma, Washington

Library of Congress Cataloging-in-Publication Data

Kokich, Vincent G., author.
Orthodontic and surgical management of impacted teeth / Vincent G. Kokich Sr, David P. Mathews.
      p. ; cm.
Includes bibliographical references.
ISBN 978-0-86715-445-0 (softcover)
I. Mathews, David P., author. II. Title.
[DNLM: 1. Tooth, Impacted--surgery. 2. Oral Surgical Procedures--methods. 3. Orthodontics-methods. WU 600]
RK521
617.6’43--dc23

2013039998

© 2014 Quintessence Publishing Co, Inc

Quintessence Publishing Co, Inc
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All rights reserved. This book or any part thereof may not be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, or otherwise, without prior written permission of the publisher.

Editor: Leah Huffman
Design: Ted Pereda
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Printed in China

Contents

Preface

1 Impacted Maxillary Central Incisors

2 Labially Impacted Maxillary Canines

3 Palatally Impacted Canines

4 Impacted Mandibular Canines

5 Impacted Premolars

6 Impacted Mandibular Molars

7 Complications and Adverse Sequelae

Preface

This publication is the culmination of Vince’s vision to write a book chronicling our 39 years of working together in an interdisciplinary manner, treating patients with impacted teeth. There has been very little written on this subject. Vince was the premier educator in orthodontics, and he felt very strongly that we should compile these cases in a very well-crafted book.

Sadly, he passed away before we were able to finish the last chapter. His longtime friend and colleague Dr Peter Shapiro; his son, Dr Vince Kokich, Jr; his daughter, Mary; and his wife, Marilyn, graciously helped me put the final touches on this fine work.

This book includes a chapter on every type of impaction an orthodontist and surgeon will encounter. It describes, in detail, the surgeries to uncover these impactions and the appropriate orthodontic mechanics to move these teeth once they are uncovered. It is the most complete, organized, and up-to-date book on this subject. It is ideal for orthodontists, pedodontists, periodontists, oral and maxillofacial surgeons, and general dentists who treat these types of cases.

We are fortunate to have so many fine orthodontists in Pierce County, Washington, who contributed to some of the cases in this book. They were all students of Vince’s, and we are indebted to them for helping us leave this exceptional legacy.

Vince was the quintessential orthodontist/teacher in the world, and it is only fitting that Quintessence helped us bring this one of a kind book to fruition.

With heartfelt gratitude,
David P. Mathews, DDS

Etiology

The most commonly impacted teeth are the mandibular third molars, followed by the maxillary canines, mandibular second premolars, and maxillary central incisors.¹ Several causes of maxillary central incisor impaction have been documented, including crowding, ² trauma,^3,4 root dilaceration,^5–9 presence of an odontoma,^10,11 presence of a dentigerous cyst,¹² or presence of a supernumerary tooth or mesiodens.^13–16 Some mesiodentes are located in the maxillary midline, between the two central incisors. In this situation, the supernumerary tooth is not blocking the path of eruption of the maxillary central incisors, and all anterior teeth potentially could erupt normally, including the mesiodens. The solution for this problem is to extract the mesiodens and close the space between the maxillary central incisors orthodontically. However, in most situations, when a mesiodens is present, it is positioned lateral to the maxillary midline and blocks the path of eruption of either the right or left central incisor. If multiple supernumerary teeth are present, both central incisors could become impacted (Fig 1-1).

If the supernumerary tooth or teeth are discovered early and extracted,¹⁷ the central incisor could erupt spontaneously (see Fig 1-2). However, the method of extraction and extent of damage to the surrounding area could disrupt the natural eruption of the central incisor(s) and result in impaction. A series of articles published by Marks et al^18–22 emphasizes the importance of the integrity of the dental follicle during the normal eruptive process. In their experiments, the researchers intentionally and selectively damaged various parts of the developing tooth bud in an attempt to disrupt the eruptive process and cause impaction of the tooth. However, intentional injury to the root and various parts of the crown of the unerupted tooth did not prevent tooth eruption. But when the dental follicle was damaged or removed, eruption stopped. These researchers believe that the integrity of the dental follicle is critical to the normal eruption of any tooth.

Therefore, if the mesiodens or supernumerary tooth can be extracted without damaging the follicle of the subjacent central incisor, the impediment to eruption will be eradicated, and the impacted central incisor should erupt. This process is illustrated in Fig 1-2. This patient was 8 years old, and the maxillary left central incisor and both maxillary lateral incisors had erupted (see Fig 1-2a). However, the right central incisor had not erupted. A periapical radiograph revealed a supernumerary tooth that was apparently blocking the eruptive path of the right central incisor (see Fig 1-2b). A labial flap was elevated, and the supernumerary tooth was identified and removed without extracting the primary central incisor or damaging the follicle of the developing right central incisor. The flap was repositioned, and the teeth were allowed to erupt. After 1 year, the right central incisor had erupted spontaneously without orthodontic intervention (see Fig 1-2c). Therefore, if the supernumerary tooth is diagnosed early and removed surgically without compromising the follicle of the impacted central incisor, the submerged tooth should erupt spontaneously.

However, in some situations, the proximity of the supernumerary tooth and the central incisor is so close that damage to the follicle of the impacted central incisor is unavoidable and inevitable. In other situations, an odontoma or dentigerous cyst may be present and in close proximity to the central incisor crown. Removal of the odontoma or cyst will usually damage the central incisor follicle, and the tooth will stop erupting. Finally, in some situations, a severely dilacerated root will cause impaction of the central incisor as a result of diversion of the tooth’s eruptive path, placing it in an oblique position within the alveolus (see Fig 1-9). In all of these situations, it is best to uncover the impacted central incisor at the same time that the other surgery is being done, assuming the root of the central incisor is adequately developed.

Preoperative Orthodontics

Usually, an impacted central incisor is recognized during the mixed dentition. At that time, all maxillary and mandibular central and lateral incisors are erupted, except for the impacted central incisor. The first step to facilitating spontaneous eruption is to extract any supernumerary teeth. If the tooth does not erupt autonomously, orthodontic treatment must be initiated to erupt the tooth.

Brackets should be placed on the remaining central incisor and the two maxillary lateral incisors. This bracket placement typically provides sufficient anchorage to erupt the impacted tooth. If the contralateral central incisor and adjacent lateral incisors are tipped toward one another, the space is opened using a compressed-coil spring. In this situation, it is necessary to place bands or brackets on the permanent maxillary first molars to provide anchorage during the course of orthodontic treatment.

After sufficient space has been established, a rectangular stabilizing wire is placed in the maxillary brackets. A loop may be placed in the archwire to temporarily anchor the attachment that will be placed on the impacted central incisor during the uncovering procedure. At this point, the patient is referred to the surgeon to uncover the impacted central incisor.

Methods of Uncovering

There are four methods for uncovering an impacted maxillary central incisor: simple excision of tissue (gingivectomy), apically positioned flap (APF), the closed eruption technique, and surgical replantation. Central incisors are usually impacted labially. The apical location of the incisor will dictate the type of uncovering technique. Choosing the correct method will create the most stable and esthetic outcome after orthodontic eruption of the impacted tooth.

Most labially impacted central incisors are uncovered with the closed eruption technique. ²³ Occasionally, the central incisor is located near or slightly coronal to the adjacent cementoenamel junction. If there is a wide zone of attached gingiva, a gingivectomy can be performed. The authors do not recommend an APF for uncovering maxillary central incisors because of the stability and esthetic problems associated with this technique.

Gingivectomy

Gingivectomy can be performed if the resultant uncovering leaves at least 3 mm of gingiva around the exposed tooth. The gingivectomy should remove approximately two-thirds of the tissue covering the crown of the impacted tooth. A bracket and/or dressing can be placed to ensure that the tissue does not re-cover the tooth. There are few indications for this method of uncovering impacted maxillary central incisors. In most situations, the impacted tooth will be located at or above the mucogingival junction (Fig 1-3). If the tooth were at this level and an excisional approach were used, it would remove most of the gingiva, leaving inadequate attached gingiva over the labial portion of the crown (see Fig 1-3).

Apically positioned flap

A second type of surgical procedure for uncovering impacted maxillary central incisors is an APF (Figs 1-4 and 1-5). This procedure will create a predictable zone of attached gingiva, because it apically positions labial gingiva over the impacted central incisor. However, there are two problems associated with this technique: reintrusion and esthetics.²⁴ Therefore, the authors no longer use this technique to uncover maxillary central incisors.

If an APF were used to uncover a complex high labial impaction, it would be likely that gingival margin discrepancies would occur. This consequence is illustrated in Fig 1-4. The maxillary right central incisor has been moved into its proper location, but the gingival margin is more apical than that of the adjacent central incisor (see Figs 1-4f and 1-4g). This case illustrates one of the reasons why the closed eruption technique is used to uncover most labially impacted teeth: It maintains the original gingival architecture. An exception is the ectopic labially impacted tooth, which must remain uncovered after surgery. This situation requires an APF so that appropriate orthodontic mechanics can be applied to properly position the tooth.

Closed eruption technique

The third technique for uncovering an impacted maxillary central incisor is the closed eruption technique.^23–27 This technique involves reflecting a flap, uncovering the impacted tooth, placing an attachment, repositioning the flap, and erupting the tooth through the crest of the alveolar ridge (Figs 1-6 and 1-7). This technique results in the most natural-appearing gingiva over the erupted tooth.^25,28,29 The crown length is usually commensurate with the nonimpacted contralateral maxillary central incisor, resulting in a more esthetic result. The closed eruption technique also eliminates the reintrusion problem after the tooth has been erupted.

The closed eruption technique is illustrated in Fig 1-6. This patient had a supernumerary tooth coronal to the maxillary left central incisor (see Fig 1-6a). Brackets were placed on the erupted maxillary incisors, and space was apportioned for the impacted central incisor (see Figs 1-6b and 1-6c). A midcrestal incision was made in the edentulous ridge and joined with vertical incisions (see Fig 1-6d), and a full-thickness pedicle flap was reflected from the edentulous ridge. The supernumerary tooth was then located (see Fig 1-6e), but it communicated with the follicle of the impacted central incisor. The follicle was perforated when the supernumerary tooth was extracted (see Fig 1-6f). Because the follicle was disrupted, the central incisor would not erupt spontaneously, and therefore the impacted tooth was uncovered. There is usually a thin shell of bone covering part of the tooth. Approximately two-thirds of the crown was exposed with appropriate bone removal using curettes and surgical round burs. The area was isolated with hemostatic agents such as Surgicel (Ethicon) or Hemodent (Premier USA) cotton pledgets. The tooth was etched, and a bonding agent was placed. It is imperative that the field be kept clean and dry. With experience, hemostasis and a dry field can be accomplished in even the most difficult areas to access.

Once the bonding agent is placed and cured, the bonding process can continue. If the area gets contaminated with blood or debris after placement of the bonding agent, it can be cleaned with an alcohol wipe. At this point, a small cleat can be bonded to the tooth, and a chain can be ligated to the cleat. The chain can also be bonded directly to the tooth (see Fig 1-6g). The chain should have small enough links so the orthodontist can clip and remove one or two links as the tooth erupts. The chain should be malleable enough to avoid breakage but hard enough to avoid stretching as force is applied. Prefabricated chains with brackets for specific teeth are available (GAC International) and are easy to bond to impacted teeth. Fourteen-carat gold replacement chain with appropriate link size can also be effective. This can be purchased from a jeweler or pawnshop and is relatively inexpensive.

The pedicle flap is then returned to its original position and sutured. The chain is covered by the flap and exits at the midcrestal incision (see Fig 1-6h). The gold chain is ligated to the bracket on the adjacent tooth. A small ligating wire or an elastomeric ligature works well to fasten the chain to the bracket. The orthodontist may begin eruption of the tooth within 1 to 2 weeks.

The closed eruption technique can also be used when the tooth is impacted high in the vestibule on the labial aspect (Fig 1-8). In Fig 1-9, the maxillary right central incisor was impacted high in the vestibule near the base of the nasal spine. It was also positioned horizontally, which further complicated the surgical access (see Figs 1-9a and 1-9b). Initially, the maxillary incisors were banded (see Fig 1-9c) and the teeth were aligned, leaving a space for the impacted right central incisor (see Figs 1-9d and 1-9e). The patient was then ready to have the tooth uncovered. The use of an APF in this situation would be injudicious, so the authors chose the closed eruption technique.