Multiple bilateral impactions in an adolescent girl

Case report Multiple bilateral impactions in an adolescent girl Giliana Clauser Zuccatia and Tiziana Doldob Florence and Siena, Italy This article describes a patient whose permanent canines and premolars had not erupted at age 14 years, although their root formation was complete, with closed apices. Surgical and orthodontic treatment was planned to correct the multiple impactions. The orthodontic traction used 5 strategic teeth and allowed for the eruption of all 12 impacted teeth. The surgical-orthodontic treatment of many impacted teeth yielded good esthetic and periodontal results, as shown by the patient’s satisfaction and the periodontal probing 2 years after the treatment. Multiple impacted teeth are a rare eruption disturbance that requires early detection: no signs of a genetic syndrome or an endocrine disorder had been found, or failure to move along the eruption path, which is a characteristic of another syndrome, primary failure of eruption. (Am J Orthod Dentofacial Orthop 2010;137:S163-72) I mpacted teeth other than third molars can be a challenge for the orthodontist. a single impacted tooth can increase the complexity of the orthodontic treatment signiicantly,1 and multiple impactions certainly complicate the treatment and lengthen the overall treatment time considerably.2 Maxillary canine impaction has an estimated incidence of 1 patient in 100 in the general population, but much higher incidences have been reported in some orthodontic practices. the estimated incidence of mandibular canine impaction is nearly 3.5 in 1000.3-5 Canine impaction is rarely associated with multiple impacted teeth; few reports have been published about such cases, with several teeth involved.6,7 a relatively high incidence of impacted teeth and delayed eruption of deciduous and permanent teeth has been observed in patients with cleidocranial dysplasia.8,9 patients with multiple impactions need careful orthodontic and surgical treatment planning: the cooperation with the surgeon is crucial to guide the eruption of as many useful teeth as possible. this patient had no permanent canines or premolars erupted at age 14 years. the teeth were markedly inclined and had complete root formation with closed a private practice, Florence, Italy. assistant professor, Department of orthodontics, University of siena, siena, Italy. the authors report no commercial, proprietary, or inancial interest in the products or companies described in this article. reprint requests to: Giliana Clauser Zuccati, via Masaccio 173, 50132 Florence, Italy; e-mail, gilzuccati@libero.it. submitted, revised, and accepted, March 2008. 0889-5406/$36.00 Copyright © 2010 by the american association of orthodontists. doi:10.1016/j.ajodo.2008.03.035 b apices. the periodontal status was reevaluated 2 years after treatment. DiaGnoSiS anD eTioloGy the patient, a 14-year-old girl, was in good physical and emotional health. Her chief complaint was having several deciduous teeth (Figs 1-3). the panoramic radiograph shows the displaced permanent teeth. she had already been sent to a physician and an endocrinologist to investigate possible systemic factors, but no signs of any genetic syndrome or endocrine disorder had been found. the mandibular deciduous canines had been extracted by a general practitioner 1 year before, but the mandibular permanent canines failed to erupt. there had been no eruption problems in the family, according to her parents. the clinical examination showed Class I molar relationships on both sides, associated with persistence of all deciduous molars and maxillary canines. part of the space of the deciduous canines in the mandibular arch was lost a year after their extraction, whereas the mandibular permanent canines remained deeply impacted and partly covered by the irst premolars. the diagnosis of multiple impactions (12 teeth excluding the third molars) was based on the complete development of the roots (closed apices) of the unerupted and malpositioned permanent teeth and the persistence of many deciduous teeth without signiicant root resorption. the mandibular permanent canines had not erupted a year after the extraction of the deciduous ones, and eruption of the other retained permanent teeth was not expected to occur in a reasonable time. the cephalometric analysis showed that the maxilla was well positioned, but the mandibular plane angle was high (sNa Go-Gn, S163 S163-172_AAOPRG_3036.indd 163 3/24/10 12:27 PM S164 Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics April 2010 Fig 1. Pretreatment extraoral and intraoral photographs, Fig 2. Pretreatment models. 39°); therefore, extrusion of the molars had to be prevented (Fig 4). TReaTMenT oBJeCTiVeS the objectives of the orthodontic treatment were to guide the eruption of the 12 impacted teeth to a S163-172_AAOPRG_3036.indd 164 functional and stable occlusion, level and align the arches, obtain normal overjet and overbite, and achieve a bilateral Class I canine and molar occlusion. Full ixed orthodontic therapy was proposed with oral surgery to expose and ligate the impacted teeth. We planned to extract a few teeth at a time to limit the damage in case of failure and maintain the second 3/24/10 12:27 PM Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics Volume 137, Number 4, Supplement 1 S165 Fig 4. Initial tracing. Fig 3. Lateral cephalometric and panoramic radiographs. Note the unerupted and malpositioned permanent teeth with complete development of the roots (closed apices) and the persistence of many deciduous teeth without signiicant root resorption. The mandibular plane angle was high (SNa Go-Gn, 39°). deciduous molars as intra-arch anchorage during the traction phase. they would be extracted only when the premolars and canines had erupted. suficient oral hygiene and periodontal health, and willingness to cooperate and wear ixed appliances were obvious prerequisites: the patient was motivated and requested the treatment to proceed as quickly as possible. the parents were informed about the expected length of the treatment and the risk of lateral incisor root resorption. a consent form for alignment of impacted or ectopic teeth was signed at the irst stage of treatment. the combined orthodontic-surgical treatment was irst planned for the mandible. because of the expected loss of space and the poor estimated probability of spontaneous eruption. the mandibular permanent canines had not erupted 1 year after extraction of the deciduous canines, and eruption of the other retained permanent teeth was not expected in a reasonable time. Uncovering the maxillary irst premolars or the palatal canines before the start of the orthodontic treatment could be another alternative. once the bone and tissue have been removed, these palatally displaced canines usually erupt in 6 to 8 months, resulting in facilitated orthodontic treatment. However, the impacted teeth were considered too deeply positioned, and a combined surgical and orthodontic approach was preferred. the choice of surgical technique—closed eruption or open eruption—was based on the canine and premolar locations: the impactions were considered too deep for open eruption, so closed eruption was considered the correct approach.10-12 all aspects of the case were considered in detail during the treatment-planning interview. a combined surgical-orthodontic approach was chosen because it allowed for extracting a few teeth at a time and hastening the eruption of the permanent teeth. alternative treatment plans would be considered in case of failure of the planned treatment because of the potential ankylosis of some permanent impacted teeth. TReaTMenT PRoGReSS TReaTMenT alTeRnaTiVeS a simple treatment alternative of extracting just the deciduous teeth was not considered an effective option S163-172_AAOPRG_3036.indd 165 Maxillary and mandibular ixed appliances on the deciduous molars and the permanent erupted teeth were used with the straight-wire technique. 3/24/10 12:27 PM S166 Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics April 2010 Fig 5. Extraoral photographs during treatment. Fig 6. Periapical radiographs and intraoral surgical photographs. The mandibular irst premolars were surgically exposed, and a button was bonded to each exposed crown as coronally as possible. Custom wire chains with 0.012-in ligatures were used. Fig 7. Closed traction of the impacted maxillary teeth with rigid rectangular arches. S163-172_AAOPRG_3036.indd 166 3/24/10 12:27 PM Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics Volume 137, Number 4, Supplement 1 S167 Table. Cephalometric measurements sNa sNB aN pg sN/Go Gn sN/aNs.pNs 1/aNs.pNs 1/Go Gn 1 to a.pg overjet overbite 1/1 Before treatment After treatment 80° 73° 6° 39° 6° 105° 86° 1.5 mm 4 mm 3 mm 126° 81° 77° 5° 38° 6° 107° 96° 2.5 mm 2 mm 2.5 mm 120° Intermaxillary Class II elastic mechanics were used, with 0.016-in nickel-titanium archwires and sequential 0.017 × 0.022-in stainless steel archwires. the patient was referred to the oral surgeon for exposure of the impacted teeth after rigid archwires were placed in both arches. surgery was irst carried out in the mandible, and the mandibular irst premolars were exposed. a button was bonded intraoperatively to each exposed crown as coronally as possible. Custom wire chains were prepared with 0.012-in ligature wire and ixed to the bonded button. the laps were then sutured back to their original positions. the chains passed under the laps and emerged at the center of the crest in the mandibular arch (Figs 5-7). subsequently, a full-thickness mucoperiosteal lap was raised palatally to reach the more supericial and accessible crown on each side.11-13 the crowns of the maxillary right irst premolar and maxillary left canine were exposed, and a gold chain was placed on each tooth as close as possible to the cusp. the gold chains emerged from the deciduous canine sockets. the laps were then repositioned and sutured in their original positions. the chains were cut at the crest level. elastic ligatures from the chains to the archwires were placed and changed every 15 days (Figs 7 and 8). the maxillary right canine was surgically exposed with the same technique when the maxillary right premolar erupted into the arch with the surgical-orthodontic traction. orthodontic traction of each exposed tooth began soon after the surgical exposure. the anchorage teeth included the second permanent molars that had completely erupted, the irst molars, and the second deciduous molars. When the irst premolars erupted, a bracket was bonded, a 0.016-in nickel-titanium wire was placed, and vertical interarch elastics were used to extrude and align the maxillary and mandibular premolars. Finally, the maxillary second deciduous molars were extracted, and the second premolars erupted palatally from the maxillary arches. the permanent canines S163-172_AAOPRG_3036.indd 167 Fig 8. Sequence of panoramic radiographs during the surgical orthodontic treatment. and premolars were aligned with nickel-titanium archwires initially and then with rigid arches. TReaTMenT ReSUlTS all impacted teeth were inally brought to their correct positions in the arches. Class I molar and canine relationships were present on both sides. the patient was pleased with the results (Figs 9 -11). the cephalometric analysis showed that the mandibular plane angle was maintained (sNa Go-Gn, 38°; table), no clockwise rotation of the mandible was noted, and the fullness of the lower lip was reduced (Fig 12). the patient was instructed to wear a removable retainer 24 hours a day for 6 months and then only at night to maintain the teeth in their correct positions. ten persistent deciduous teeth were extracted and 5 permanent teeth were surgically exposed. the treatment lasted 3.5 years and required 88 visits. No sign of root resorption, vitality impairment, or other damage to the lateral incisors and canines was observed during 3/24/10 12:27 PM S168 Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics April 2010 Fig 9. Posttreatment extraoral and intraoral photographs. A less than 1-mm Class II relationship persisted on the right side. Fig 10. Posttreatment models. treatment. periodontal evaluation at the end of the treatment showed healthy marginal tissues, with pale pink and irm gingivae, and probing depths were not greater than 3 mm (Fig 13). shallow pseudopockets were observed on the buccal aspect of the impacted teeth that S163-172_AAOPRG_3036.indd 168 had erupted palatally: the maxillary right canine and right and left second premolars. the right canine had a shorter crown, but the patient was satisied with the result; surgical crown lengthening could still be performed later, if needed or requested. 3/24/10 12:27 PM American Journal of Orthodontics and Dentofacial Orthopedics Volume 137, Number 4, Supplement 1 Zuccati and Doldo S169 two years after treatment, the periodontal evaluation conirmed healthy marginal tissues, with no loss of clinical attachment and with probing depths less than 3 mm. In the maxillary left second molar, there was a probing depth of 3 mm on the distal aspect (Fig 14). the patient was sent to the oral surgeon for extraction of the third molars to prevent periodontal or dental damage to the second molars. DiSCUSSion Multiple impacted teeth might be related to genetic or metabolic disorders. tooth eruption is a localized event that requires the expression of various molecules at appropriate times to regulate bone resorption and bone formation. eruption and development of the dentition can be hampered and delayed by irregular bone remodeling adjacent to the tooth bud and crown. the rate of bone remodeling is controlled by local and systemic factors. systemic control of bone remodeling occurs through several endocrine mechanisms, including parathyroid hormone, vitamin D3, and sex steroids (eg, estrogens). these factors seem to act on osteoclasts as intermediaries to regulate osteoblast-osteclast equilibrium, which ultimately affects the expression of the speciic genes that are necessary to synthesize proteins involved in bone remodeling.14,15 systemic factors could play a role in determining multiple impactions, but this patient had gone to a physician and an endocrinologist, and no signs of genetic syndromes or endocrine disorders were found. Multiple impactions involving premolars and canines is a rare condition. More information is available about “primary failure of eruption,” a term coined by profit and Vig16 to describe a condition in which malfunction of the eruption mechanism causes failure of eruption: the permanent teeth begin to erupt into the oral cavity, but they do not erupt completely. a typical feature of primary failure of eruption is that no tooth erupts distally to any unerupted tooth. In this patient, the irst and second permanent molars had erupted spontaneously. this patient’s diagnosis of multiple impaction was based on the extreme unlikelihood that spontaneous eruption of all canines and premolars would occur even after extracting the corresponding persistent deciduous teeth. In turn, this judgment was based on the patient’s age (14 years), her history (the mandibular canines had not erupted a year after extraction of the corresponding deciduous teeth), and the panoramic radiograph, in which the premolars and permanent canines appeared to be markedly inclined and had fully formed roots with closed apices. these features contrast with the usual criterion for spontaneous eruption: teeth are expected S163-172_AAOPRG_3036.indd 169 Fig 11. Final radiographs: the patient was sent to the surgeon for extraction of the third molars. to erupt normally when only half to three quarters of their roots have developed. “Delayed eruption” refers to teeth that are expected to erupt spontaneously even though the roots are more fully developed.17 Criteria for delayed eruption include absence of anatomic obstacles, suficient space in the arch, and favorable inclination of the unerupted tooth. the inclinations were unfavorable in our patient, and the shallower impactions appeared to hinder the eruption of the deeper ones. only 5 of 12 impactions were driven directly to the arch by surgical-orthodontic traction, but the hypothesis that the other teeth would erupt spontaneously is questionable, even if an alternative treatment is considered that would consist only of extractions of deciduous teeth and space maintainers. the clinical and radiologic features and the progress of the treatment suggest that the surgical orthodontic traction of 5 impacted teeth had a signiicant beneicial effect even on the neighboring impactions, making their eruption, albeit in bad positions, possible. In particular, the forced eruption of the irst premolars was supposed to have removed a signiicant obstacle for the canines and provided a stimulus for the second premolars. the clinical guidelines of the american academy of pediatric Dentistry recommend early detection of 3/24/10 12:27 PM S170 Zuccati and Doldo American Journal of Orthodontics and Dentofacial Orthopedics April 2010 Fig 12. Final tracing and superimposition: the cephalometric analysis showed that the mandibular plane angle was maintained (SNa Go-Gn, 38°). Fig 13. Periodontal evaluation conirmed healthy marginal tissues. A 3-mm probing depth was present on the maxillary second molar. an ectopically erupting canine to minimize such an occurrence.18 extraction of the primary canines is recommended as the treatment of choice when trying to correct palatally impacted canines, if there are normal S163-172_AAOPRG_3036.indd 170 space conditions and no incisor resorption. In this patient, panoramic and periapical ilms were taken to locate potentially ectopic canines, as recommended, and the mandibular deciduous canines had been extracted 3/24/10 12:27 PM American Journal of Orthodontics and Dentofacial Orthopedics Volume 137, Number 4, Supplement 1 Zuccati and Doldo S171 Fig 14. The horizontal blue line represents the cementoenamel junction level; the second blue line represents the gingival margin. The 2 lines are superimposed because the gingival margin is at the cementoenamel junction; the red line represents the probing attachment level (Periochart Software, Sorriso Dental Trey, Forlì, Italy). 1 year before the orthodontic visit. the permanent mandibular canines failed to erupt after 1 year, and a combined orthodontic and surgical approach was undertaken as suggested by the same clinical guidelines. Kokich and Mathews12 recommended an alternative technique, early uncovering of the palatally impacted canines. Uncovering palatal canines is usually timed before the start of orthodontic treatment, during the late mixed dentition. a full-thickness mucoperiosteal lap is elevated in the area of the impacted canine, and all bone over the crown is removed down to the cementoenamel junction. the lap is repositioned, and a hole is made through the gingival lap. once the bone and tissue have been removed, these palatally displaced canines will erupt on their own in 6 to 8 months. at that point, a bracket is placed on the tooth, and orthodontic treatment begins. the uncovering approach has been so far applied only to supericial palatally impacted maxillary canines. In this patient, all impacted teeth, including the maxillary canines, were deep within the alveolar process: they were not expected to erupt on their own if left uncovered, because the tissues would grow over the tooth. the closed-eruption technique was preferred because of the deep position of most of the impacted premolars and canines, and the patient was disappointed with the mandibular canines’ failure to erupt after the extraction of the deciduous teeth and requested a fast solution. the surgery was irst carried out in the mandible: both mandibular irst premolars underwent surgical S163-172_AAOPRG_3036.indd 171 exposure; orthodontic traction began immediately after the irst surgical session. Impaction of the mandibular teeth is uncommon, and anchorage can be a problem during orthodontic traction.12 the ixed appliances in the maxilla can serve as anchorage if the deciduous and permanent mandibular molars are not suficient. In this patient, the surgical-orthodontic treatment of multiple impacted teeth yielded good esthetic and periodontal results, as shown by periodontal probing 2 years after treatment. surgical traction on the strategic teeth allowed for the eruption of the other impacted teeth. radiographs were taken for the surgical exposure of the impacted premolars and canines (Fig 8). three-dimensional imaging would have been more informative but would have exposed the patient to an additional heavy dose of ionizing radiation. this extra dose was not justiied, since panoramic and periapical radiographs were suficient to localize the impacted teeth even in the buccolingual direction, and possible minor root resorption of the lateral incisors would not have changed the treatment plan. Clinicians are advised to use the principle of “as low as reasonably achievable.” the use of computed tomography might be unethical if the relevant information can be gathered with less invasive procedures.19,22 polytomography imaging was planned to determine the correct traction direction during closed traction if the impacted teeth did not move. the surgical traction technique has proven highly reliable in young patients 3/24/10 12:27 PM S172 Zuccati and Doldo with good oral hygiene and proper maintenance. It allows for driving the tooth toward the midcrestal area, simulating the natural eruptive path.11-13 the maxillary deciduous second molars were maintained in the irst leveling of the arches and then as anchorage. palatal arches could have been used to increase the anchorage, but we thought that the anchorage was suficient on the irst and second molars; the second deciduous molars were extracted only after the eruption of the other impacted teeth. the treatment required 88 visits, an unusually long time for an adolescent patient.1 the high number of visits was mainly due to changing the elastic ligatures from the chain to the rigid archwires and to attaching, aligning, and rotating teeth once erupted. the force of the ligatures was no longer suficient to continue the eruption after 2 weeks. a retrospective study compared the durations of treatment (from exposure to debond) of 25 patients treated by the open-eruption method with 25 patients treated by the closed-eruption technique.23 the mean treatment duration was exactly the same for each group (28.8 months). Multiple impacted teeth is a rare eruption disturbance that requires early detection. No signs of genetic syndromes, endocrine disorders, or failure to move along the eruption path, which is a characteristic of primary failure of eruption, was detected. Further investigation is needed. We thank roberto Barone, the oral surgeon who planned the surgical treatment and took the surgical pictures of this patient. ReFeRenCeS 1. Zuccati 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;130:349-56. 2. Conley rs, Boyd sB, Legan HL, Jernigan CC, starling C, potts C. treatment of a patient with multiple impacted teeth. angle orthod 2007;77:735-41. 3. Bishara se. Clinical management of impacted canines. semin orthod 1998;4:87-98. 4. 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Burden DJ, Mullally BH, robinson sJ. palatally ectopic canines: closed eruption versus open eruption. am J orthod Dentofacial orthop 1999;115:634-9. 11. Crescini a, Clauser C, Giorgetti r, Cortellini p, pini prato Gp. tunnel traction of infraosseous impacted maxillary canines. a three-year periodontal follow-up. am J orthod Dentofacial orthop 1994;105:61-73. 12. Kokich VG, Mathews Da. Impacted teeth: surgical and orthodontic considerations. In: McNamara Ja Jr, editor. orthodontics and dentofacial orthopedics. ann arbor, Mich: Needham press; 2004. p. 395-422. 13. Kokich VG. surgical and orthodontic management of impacted maxillary canines. am J orthod Dentofacial orthop 2004;126:278-83. 14. Huang GC, King G, Kapila s. Biologic mechanisms in orthodontic tooth movement. In: Nanda r, editor. Biomechanics and esthetics strategies in clinical orthodontics. st. Louis: elsevier saunders; 2005. p. 17-37. 15. Yao s, pan F, Wise Ge. Chronological gene expression of parathyroid hormone-related protein (ptHrp) in the stellate reticulum of the rat: implications for tooth eruption. arch oral Biol 2007;52:228-32. 16. Frazier-Bowers s, Koehler Ke, ackerman GL, profit Wr. primary failure of eruption: further characterization of a rare eruption disorder. am J orthod Dentofacial orthop 2007;131:578.e1-11. 17. Becker a, Chaushu s. Dental age in maxillary dental ectopia. am J orthod Dentofacial orthop 2000;117:657-62. 18. american academy of pediatric Dentistry. Clinical guideline on pediatric oral surgery. Chicago: american academy of pediatric Dentistry; 2005. 19. British orthodontics standards Working party. Guidelines for the use of radiographs in clinical orthodontics. London: British orthodontic society; 1994. 20. Dula K, Mini r, van der stelt pF, Lambrecht Jt, schneeberger p, Buser D. Hypothetical mortality risk associated with spiral computed tomography of the maxilla and mandible. eur J oral sci 1996;104:503-10. 21. National radiological protection Board. Guidelines on radiology standards for primary dental care documents of the NrpB;1998;5:11,16,24. 22. White sC. assessment of radiation risk from dental radiography. Dentomaxillofac radiol 1992;21:118-26. 23. Iramaneerat s, Cunningham sJ, Horrocks eN. the effect of two alternative methods of canine exposure upon subsequent duration of orthodontic treatment. Int J paed Dent 1998;8:123-9. 3/24/10 12:27 PM