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Palatally impacted canines: The case for closed surgical exposure and immediate orthodontic traction

2013; Elsevier BV; Volume: 143; Issue: 4 Linguagem: Inglês

10.1016/j.ajodo.2013.02.012

1097-6752

Adrian Becker, Stella Chaushu,

Cleft Lip and Palate Research

Our eminent discussants, Drs Mathews and Kokich, have provided a general overview of the problems associated with the surgical and orthodontic modality of the treatment of impacted maxillary canines, together with the available interceptive options. There is very little there with which one might take issue, but 1 point does require modification. Root resorption of the adjacent lateral incisor is not an aftermath of properly conducted treatment. Rather, it is a condition, which, with the benefit of cone-beam technology, has been shown to affect two thirds of the patients seen in our clinics, before treatment is initiated.1Walker L. Enciso R. Mah J. Three-dimensional localization of maxillary canines with cone-beam computed tomography.Am J Orthod Dentofacial Orthop. 2005; 128: 418-423Abstract Full Text Full Text PDF PubMed Scopus (245) Google Scholar It is a progressive phenomenon and ceases only when the canine becomes distanced from its intimate contact with the incisor root.2Ericson S. Kurol P.J. Resorption of incisors after ectopic eruption of maxillary canines: a CT study.Angle Orthod. 2000; 70: 415-423PubMed Google Scholar, 3Becker A. Chaushu S. Long-term follow-up of severely resorbed maxillary incisors after resolution of an etiologically associated impacted canine.Am J Orthod Dentofacial Orthop. 2005; 127: 650-654Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar, 4Ericson S. Bjerklin K. Falahat B. Does the canine dental follicle cause resorption of permanent incisor roots? A computed tomographic study of erupting maxillary canines.Angle Orthod. 2002; 72: 95-104PubMed Google Scholar Alternatively, it might be the sequel to improper directional orthodontic traction that drives the canine directly against the incisor root. But this is faulty technique and, thus, irrelevant to the present discussion, in which we must assume the best treatment performance. The interceptive methods of treating impacted canines are well known but are not at issue in this debate. In the ideal approach to the closed exposure strategy, as we see it, the orthodontist is present and will have tied-in a custom-designed traction spring during the few minutes between administration of the local anesthetic and its becoming effective.5Becker A. The orthodontic treatment of impacted teeth. Wiley-Blackwell, Oxford, United Kingdom2012Crossref Scopus (6) Google Scholar Once the tooth is exposed, an attachment is bonded to it, and, after full replacement of the surgical flap, active traction is applied. The patient can then be seen a month or so later before further activation is needed. Quoting from their earlier study in their description of the open exposure technique, our discussants noted that autonomous eruption occurs within 6 to 9 months postoperatively, although there is apparently no report in the literature to support this statement.6Schmidt A.D. Kokich V.G. Periodontal response to early uncovering, autonomous eruption, and orthodontic alignment of palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2007; 131: 449-455Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar Their study describes the results from 49 consecutive patients who had at least 1 previous palatally impacted canine that had been exposed and allowed to erupt into the palate. They did not say in how many patients eruption had not occurred, how many teeth were deemed intractable and were extracted, and how many patients were found to be unsuitable for this method and referred for other treatment. There can be no argument that exposure of some impacted canines alone leads to autonomous eruption in time. However, no study has been initiated to discover which canines will respond in this way and which will fail, nor the speed with which eruption will occur in the successful cases. Failure will inevitably mean renewed surgery for our young patient. Success will usually have been the result of more radical surgery and exposure of the tooth, up to or beyond the cementoenamel junction; although the periodontium might be healthy in the long term, the labial aspect of the clinical crown will most likely be longer, with exposure of the cementum on the lingual side. This is not the experience that we have seen with the closed technique. Resorption because of a canine crown “(being) moved into close contact with the root of the adjacent lateral incisor” can only occur (in either technique) if the direction of traction has not been properly determined or appropriately executed. This represents faulty treatment technique and, as such, is irrelevant to this discussion. Neither are the 2 literature references quoted in support of that assertion appropriate, since the authors had examined pretreatment records only.7Kim Y. Hyun H.K. Jang K.T. The position of maxillary canine impactions and the influenced factors to adjacent root resorption in the Korean population.Eur J Orthod. 2012; 34: 302-306Crossref PubMed Scopus (36) Google Scholar, 8Yan B. Sun Z. Fields H. Wang L. Maxillary canine impaction increases root resorption risk of adjacent teeth: a problem of physical proximity.Am J Orthod Dentofacial Orthop. 2012; 142: 750-757Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar We have no comment in regard to the fact that impacted teeth in adults tend to respond much later than do those in children or to the explanations given for this. However, since we have experienced failure of teeth to erupt despite the application of traction in patients in their fourth and fifth decades of life, we have advised placement of a temporary anchorage device in the palate at the time of closed exposure and the immediate application of elastic traction for several months, until positive signs of movement are seen. Only then do we place orthodontic appliances on the other teeth and reevaluate our treatment options in light of the outcome.9Chaushu S. Chaushu G. Becker A. Skeletal implant anchorage in the treatment of impacted teeth—a review of the state of the art.Semin Orthod. 2010; 16: 234-241Abstract Full Text Full Text PDF Scopus (6) Google ScholarWe believe that creating space orthodontically before a minimal surgical exposure, bonding a small attachment (an eyelet), full-flap closure, and immediate traction is a safe and predictable option for treating palatally impacted maxillary canines in adolescents and adults. We believe that creating space orthodontically before a minimal surgical exposure, bonding a small attachment (an eyelet), full-flap closure, and immediate traction is a safe and predictable option for treating palatally impacted maxillary canines in adolescents and adults. Does the preorthodontic uncovering and autonomous eruption method reduce treatment time? Schmidt and Kokich6Schmidt A.D. Kokich V.G. Periodontal response to early uncovering, autonomous eruption, and orthodontic alignment of palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2007; 131: 449-455Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar reported an average treatment time of 33 months, with the preorthodontic procedure taking a further 6 to 9 months, for approximately 40 months in all. Yet, in the literature, we find results from immediate traction methods producing treatment times of 25.8 and 32.3 months for unilateral and bilateral cases, respectively10Stewart J.A. Heo G. Glover K.E. Williamson P.C. Lam E.W. Major P.W. Factors that relate to treatment duration for patients with palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2001; 119: 216-225Abstract Full Text Full Text PDF PubMed Scopus (181) Google Scholar; 26.3 months11Fleming P.S. Scott P. Heidari N. Dibiase A.T. Influence of radiographic position of ectopic canines on the duration of orthodontic treatment.Angle Orthod. 2009; 79: 442-446PubMed Google Scholar; 19.7 months12Becker A. Chaushu S. Success rate and duration of orthodontic treatment for adult patients with palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2003; 124: 509-514Abstract Full Text Full Text PDF PubMed Google Scholar; and 22 months.13Baccetti T. Crescini A. Nieri M. Rotundo R. Pini Prato G.P. Orthodontic treatment of impacted maxillary canines: an appraisal of prognostic factors.Prog Orthod. 2007; 8: 6-15PubMed Google Scholar For adults, it has been reported that treatment takes much longer14Harzer W. Seifert D. Mahdi Y. The orthodontic classification of impacted canines with special reference to the age at treatment, the angulation and dynamic occlusion.Fortschr Kieferorthop. 1994; 55: 47-53Crossref PubMed Scopus (19) Google Scholar; that 30 more visits were required than for children15Zuccati G. Ghobadlu J. Nieri M. Clauser C. Factors associated with the duration of forced eruption of impacted maxillary canines: a retrospective study.Am J Orthod Dentofacial Orthop. 2006; 130: 349-356Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar; and that 10 more visits were required than for children, 9 of which directly related to the canine.12Becker A. Chaushu S. Success rate and duration of orthodontic treatment for adult patients with palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2003; 124: 509-514Abstract Full Text Full Text PDF PubMed Google Scholar In the closed eruption technique, bone is left intact around the crown of the impacted tooth, even when it lies in the path of the intended direction of the proposed traction. Experience derived from many patients treated this way has shown that the teeth respond rapidly to the applied force. There are indeed no cells capable of resorbing bone at the enamel-alveolar bone interface, but pressure demonstrably produces bone resorption and remodeling on the pressure side in exactly the same way as it does for every erupted tooth subjected to an orthodontic procedure that we perform in our offices every day.16Wise G.E. King G.J. Mechanisms of tooth eruption and orthodontic tooth movement.J Dent Res. 2008; 87: 414-434Crossref PubMed Scopus (390) Google Scholar The applied force causes hyalinization and undermining resorption, which quickly disappear due to physiologic activity of scavenging cells in the immediate area. This has been demonstrated in relation to deeply embedded teeth that have been left for many months before traction is applied (when bone will have regenerated over the tooth), to cases of increased bone density (cleidocranial dysplasia), to canines associated with resorption of incisor roots (impossible to expose fully), and even to erupting an impacted tooth through an autogenous or synthetic bone graft.17Becker A. Casap N. Chaushu S. Conventional wisdom and the surgical exposure of impacted teeth.Orthod Craniofac Res. 2009; 12: 82-93Crossref PubMed Scopus (13) Google Scholar At the end of the process, there are no signs of pathology, and use of the term “pathologic pressure necrosis” is highly misleading, since it is part and parcel of the achievement of a successful outcome in all our orthodontic patients, whether they are routine or have an impaction.16Wise G.E. King G.J. Mechanisms of tooth eruption and orthodontic tooth movement.J Dent Res. 2008; 87: 414-434Crossref PubMed Scopus (390) Google Scholar Furthermore, the references to our work have been misquoted,18Becker A. Kohavi D. Zilberman Y. Periodontal status following the alignment of palatally impacted canine teeth.Am J Orthod. 1983; 84: 332-336Abstract Full Text PDF PubMed Scopus (53) Google Scholar, 19Kohavi D. Becker A. Zilberman Y. Surgical exposure, orthodontic movement, and final tooth position as factors in periodontal breakdown of treated palatally impacted canines.Am J Orthod. 1984; 85: 72-77Abstract Full Text PDF PubMed Scopus (76) Google Scholar since closed surgery was reported there as showing marginally less bone support than an unaffected canine, but greater bone support than cases of open exposure.20Vermette M.E. Kokich V.G. Kennedy D.B. Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques.Angle Orthod. 1995; 65: 23-32PubMed Google Scholar The following is a description of our updated version of the closed eruption technique.1.Leveling and alignment of the teeth in the maxilla, followed by creating the space in the canine location.2.Accurately diagnosing the 3-dimensional location and orientation of the canine in space and in relation to the roots of the adjacent erupted teeth, from suitable plane film radiographs, although cone-beam computerized tomography is strongly preferred.21Chaushu S. Chaushu G. Becker A. The role of digital volume tomography in the imaging of impacted teeth.World J Orthod. 2004; 5: 120-132PubMed Google Scholar3.Determining the direction that traction must be applied to eliminate the impaction or entanglement with adjacent roots and designing an auxiliary spring,22Jacoby H. The “ballista spring” system for impacted teeth.Am J Orthod. 1979; 75: 143-151Abstract Full Text PDF PubMed Scopus (55) Google Scholar an auxiliary labial arch,23Kornhauser S. Abed Y. Harari D. Becker A. The resolution of palatally impacted canines using palatal-occlusal force from a buccal auxiliary.Am J Orthod Dentofacial Orthop. 1996; 110: 528-534Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar a light palatal archwire,24Becker A. Zilberman Y. The palatally impacted canine: a new approach to treatment.Am J Orthod. 1978; 74: 422-429Abstract Full Text PDF PubMed Scopus (19) Google Scholar or an elastic traction hook, for example, to achieve this.4.Exposing the tooth (by the surgeon) with a minimum of bone removal to reveal the follicle, which is opened at the most superficial point only. Bone is not cleared away from the neck of the tooth, nor is any attempt made to remove more of the follicular tissue than is essential for bonding, and certainly not down to the cementoenamel junction.5Becker A. The orthodontic treatment of impacted teeth. Wiley-Blackwell, Oxford, United Kingdom2012Crossref Scopus (6) Google Scholar5.A small eyelet, threaded with soft twisted ligature wire of 0.012-in gauge, is then bonded (ideally by the orthodontist in attendance) while hemostasis is maintained (by the surgeon).6.The flap is then sutured fully back to its former place to cover the entire wound and exposed area, with the twisted ligature wire drawn through the flap at a point strategically placed to permit traction in the direction that will have been confirmed when the orthodontist actually sees the tooth in situ.7.The ligature is then immediately engaged by the spring mechanism before the patient leaves the surgeon's couch. The next activation would be made about a month later, when healing is well advanced and the tissues are not unduly sensitive. It is probably true to say that canines whose impacted location is relatively superficial can benefit from either method with little to distinguish between them, but equally it is true that some canines whose location and relationship to the roots of adjacent teeth make an open exposure out of the question. A canine that is associated with severe resorption of the root of the incisor cannot be exposed and left to erupt without seriously endangering the vitality and, often, the existence of the incisor, whereas a closed eruption technique can be the salvation of both teeth in a vital state.5Becker A. The orthodontic treatment of impacted teeth. Wiley-Blackwell, Oxford, United Kingdom2012Crossref Scopus (6) Google Scholar Palatal canines that are severely vertically displaced in the height of the maxilla, above the incisor apices, or those whose roots traverse the ridge to the labial side of the lateral incisor, cannot be treated by an open exposure technique; in contrast to treatment by a closed technique, these would be scheduled for extraction.25Becker A. Extreme tooth impaction and its resolution.Semin Orthod. 2010; 16: 222-233Abstract Full Text Full Text PDF Scopus (7) Google Scholar They would then be eliminated from the study sample in a retrospective investigation of the periodontal condition of the outcome. The surgical flap is fully replaced at the end of treatment, thereby closing off the open wound to the oral environment. In this way, morbidity is lower than for open procedures, healing is faster, postoperative pain is considerably reduced, and postsurgical bleeding is virtually eliminated. In a series of quality-of-life studies performed in Jerusalem, we found that the after-pain, postsurgical discomfort, and loss of function were negative features that lasted approximately twice as long in patients after open surgery compared with those having closed surgical procedures.26Chaushu G. Becker A. Zeltser R. Branski S. Chaushu S. Patients' perceptions of recovery after exposure of impacted teeth with a closed-eruption technique.Am J Orthod Dentofacial Orthop. 2004; 125: 690-696Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar, 27Chaushu S. Becker A. Zeltser R. Vasker N. Chaushu G. Patients' perceptions of recovery after surgical exposure of impacted maxillary teeth treated with an open-eruption surgical-orthodontic technique.Eur J Orthod. 2004; 26: 591-596Crossref PubMed Scopus (14) Google Scholar, 28Chaushu S. Becker A. Zeltser R. Branski S. Vasker N. Chaushu G. Patients' perception of recovery after exposure of impacted teeth: a comparison of closed- versus open-eruption techniques.J Oral Maxillofac Surg. 2005; 63: 323-329Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar In several earlier studies in Jerusalem, in which the periodontal outcome of the treatment of impacted canines was reported, the patients who had the closed procedure showed significantly better results.18Becker A. Kohavi D. Zilberman Y. Periodontal status following the alignment of palatally impacted canine teeth.Am J Orthod. 1983; 84: 332-336Abstract Full Text PDF PubMed Scopus (53) Google Scholar, 19Kohavi D. Becker A. Zilberman Y. Surgical exposure, orthodontic movement, and final tooth position as factors in periodontal breakdown of treated palatally impacted canines.Am J Orthod. 1984; 85: 72-77Abstract Full Text PDF PubMed Scopus (76) Google Scholar Similar studies and outcomes have been reported elsewhere.20Vermette M.E. Kokich V.G. Kennedy D.B. Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques.Angle Orthod. 1995; 65: 23-32PubMed Google Scholar, 29Crescini A. Clauser C. Giorgetti R. Cortellini P. Pini Prato G.P. Tunnel traction of infraosseous impacted maxillary canines. A three-year periodontal follow-up.Am J Orthod Dentofacial Orthop. 1994; 105: 61-72Abstract Full Text PDF PubMed Scopus (75) Google Scholar, 30Hunt N.P. Direct traction applied to unerupted teeth using the acid-etch technique.Br J Orthod. 1977; 4: 211-212PubMed Google Scholar, 31McBride L.J. Traction—a surgical/orthodontic procedure.Am J Orthod. 1979; 76: 287-299Abstract Full Text PDF PubMed Scopus (24) Google Scholar, 32McDonald F. Yap W.L. The surgical exposure and application of direct traction of unerupted teeth.Am J Orthod. 1986; 89: 331-340Abstract Full Text PDF PubMed Scopus (67) Google Scholar, 33Wong-Lee T.K. Wong F.C. Maintaining an ideal tooth-gingiva relationship when exposing and aligning an impacted tooth.Br J Orthod. 1985; 12: 189-192PubMed Google Scholar, 34Wisth P.J. Norderval K. Boe O.E. Periodontal status of orthodontically treated impacted maxillary canines.Angle Orthod. 1976; 46: 69-76PubMed Google Scholar These studies have been repeated for impacted maxillary central incisors, and again the results favored closed surgical exposure.35Becker A. Brin I. Ben-Bassat Y. Zilberman Y. Chaushu S. Closed-eruption surgical technique for impacted maxillary incisors: a postorthodontic periodontal evaluation.Am J Orthod Dentofacial Orthop. 2002; 122: 9-14Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar, 36Chaushu S. Brin I. Ben-Bassat Y. Zilberman Y. Becker A. Periodontal status following surgical-orthodontic alignment of impacted central incisors with an open-eruption technique.Eur J Orthod. 2003; 25: 579-584Crossref PubMed Scopus (29) Google Scholar, 37Chaushu S. Dykstein N. Ben-Bassat Y. Becker A. Periodontal status of impacted maxillary incisors uncovered by 2 different surgical techniques.J Oral Maxillofac Surg. 2009; 67: 120-124Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar There is no need for the placement of surgical packs that are not well tolerated and become unhygienic, even after 1 week in the mouth. The mere thought of leaving a pack in the mouth for 5 months would undermine the patient's quality of life. By making a minimal entry into the dental follicle and leaving the majority in place, the closed eruption technique leaves the cementoenamel junction area untouched. The normal gingival cuff will eventually be created with a junctional epithelial attachment on the cervical area of the crown of the tooth, directly on enamel. This is achieved through the fine layer of hemidesmosomes, cells that originate in the reduced enamel epithelium on the inner surface of the follicle, as the tooth breaks through the gingiva and during the follicle's metaplasia to become continuous with the gingival tissue. At the completion of treatment, the orthodontically erupted canine will appear as any newly erupted tooth, with a short clinical crown due to exuberant gingival tissue, which later retracts and makes the tooth clinically indistinguishable from any normally erupting tooth. We have noted above that the overall aims of treatment, by either method, include the ability to treat to the highest clinical standard. The ideal outcome demands that it be impossible to distinguish in the dental arch which was the previously impacted tooth, because its appearance, orientation, color, and gingival contour and height are identical with its antimere and in harmony with its neighbors. This is achievable in a high proportion of patients when the closed eruption technique is used in combination with properly executed directional orthodontic traction and alignment. For the preorthodontic open exposure method, only 19% of the previously impacted canines could escape detection by a panel of experts.6Schmidt A.D. Kokich V.G. Periodontal response to early uncovering, autonomous eruption, and orthodontic alignment of palatally impacted maxillary canines.Am J Orthod Dentofacial Orthop. 2007; 131: 449-455Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar One final point relates to a pathologic condition that is uncommon, but familiar to endodontists, pediatric dentists, and dental traumatologists, although orthodontists seem to be entirely unaware of its existence. Invasive cervical root resorption is a condition seen after physical trauma, usually from a fall or a blow received by a child at school, or from chemical trauma from the leeching out of chemicals introduced into the occluded pulp chamber of root-treated teeth for bleaching. Impacted teeth are vital, but a radical exposure surgery taken down to the cementoenamel junction might denude the root surface and, with damage to the cementum layer, invasive cervical root resorption could begin at that site. Invasive cervical root resorption is a lesion, which, in its early stages, is difficult to diagnose on a radiograph, but, by the time the lesion has grown, bone is usually deposited in the depth of the resorption lacunae, and the tooth will no longer respond to extrusive traction.38Becker A. Abramovitz I. Chaushu S. Failure of treatment of impacted canines associated with invasive cervical root resorption.Angle Orthod. 2013 Jan 23; ([Epub ahead of print])PubMed Google Scholar It is our view that this is the cause of many failed impacted teeth, rather than the knee-jerk and usually unproven application of the label “ankylosis.” Avoidance of extensive surgery down to the cementoenamel junction would appear to be called for, to reduce the likelihood of this possible sequel. Our conclusions are identical to those of our respected discussants. We believe that creating space orthodontically before a minimal surgical exposure, bonding a small attachment (an eyelet), full-flap closure, and immediate traction is a safe and predictable option for treating palatally impacted maxillary canines in adolescents and adults. Our research and clinical experience show that this technique provides significant benefits to the orthodontist and the patient with a minimal risk of morbidity or failure of eruption.