2020, Number 2
Orthodontic treatment in a skeletal class II patient with superior ectopic canines
Full text
Language: English/Spanish [Versión en español]
References: 18
Page: 135-144
PDF size: 510.54 Kb.
ABSTRACT
Introduction: Ectopic eruption is a frequent anomaly, reported in canines in approximately 1.5-2% of the population, being more frequent in females in a ratio of 2:1. Different studies report around 20% of eruption anomalies. Case report: A 12-year-old female patient, with dolichofacial facial biotype, convex profile, enlarged lower facial third. She presents class II skeletal with posterior mandibular rotation. Class I molar, class canine unestablished, right unilateral posterior crossbite, triangular-shaped upper arch and ovoid-shaped lower arch, inferior midline deviation 2 mm to the left, overjet 3 mm and overbite 3.5 mm, maxillary and mandibular arch length discrepancy (-9.8 mm and -10.9 mm, respectively), lower incisors proclined and protruded, and curve of Spee of 2 mm. Treatment with upper and lower first premolars extractions. Placement of transpalatal arch, lingual arch and Roth slot 0.018" brackets. Alignment and levelling: 0.016" thermal archwires, 0.016" stainless steel (SS), 0.016" × 0.022" thermal archwires. Work phase: 0.016" × 0.022" SS, 0.017" × 0.025" SS and arch coordination. Detailing and finishing. Retention: upper and lower circumferential retainer. Results: right unilateral posterior crossbite and crowding was eliminated, class I canine was established, class I molar was maintained, adequate overjet and overbite, correction of Spee's curvature, appropriate shape of the dental arch and profile improvement by decreasing facial convexity. Conclusions: Whenever space is lacking and the profile needs to be corrected, ectopic canines should be placed in the first premolar area and an adequate anterior guidance can be established. Premolar extraction is an excellent treatment option when all diagnostic means are taken into consideration.INTRODUCTION
Dental malocclusions are developmental disorders that correspond to clinical deviations in the normality of: spatial relationships, growth and morphology, between the maxillary bone bases, the dental organs, and of these with the jaws. Thus, malocclusions can be dental, skeletal and/or dentoskeletal dysplasias.1
Malocclusions are multifactorial in origin, however, genetic predisposition and exogenous or environmental factors are the main components that can define their aetiology and include all the elements capable of conditioning a malocclusion during craniofacial development.2
Class II malocclusion, also called distoclusion, occurs when the mesiobuccal cusp of the first superior molar occludes in front of the mesiobuccal cusp of the first inferior molar occludes. The teeth of the upper arch and the maxilla are positioned mesially in relation to the mandible. Within class II malocclusion two varieties are distinguished: 1) class II division 1 malocclusion: when the upper incisors are protruded, with an increased overjet. 2) Class II division 2 malocclusion: when the upper central incisors are in coronary retroclination, with the lateral incisors in vestibular-version, decreased overjet and deep bite in the anterior dentition.3,4
Malocclusion behavior worldwide ranges from 35 to 75%, with gender and age differences. Crowding is the most frequent anomaly, contributing to malocclusion with approximately 40 to 85%.5
Ectopic eruption, or eruption elsewhere, is a very common anomaly. The eruption of ectopic canines has been reported to occur in approximately 1.5 to 2% of the population, being more frequent in females in a ratio of 2:1.6 In different studies, canines present around 20% of eruption anomalies.7 The upper canines are the last teeth to erupt before the third molars and therefore have a greater tendency to suffer problems of space in the arch, as well as anomalies in their eruption.8 The most common environmental causes of ectopic canines include (one or more of the following list): dental arch length discrepancy, early or late exfoliation (shedding) of the temporal canine, abnormal position of the permanent canine follicle, presence of alveolar cleft, ankylosis, cystic or neoplastic formation, root dilaceration, iatrogenic origin or idiopathic causes.9,10
Furthermore, orthodontic treatment is not only about dental and skeletal improvements, but also about soft tissue improvements.11
The following case is the treatment of an adolescent patient with a malocclusion class II skeletal and ectopic canines. The treatment indicated upper and lower first premolars extractions for the correct position of the canines and to improve the facial profile.
CLINICAL CASE
DIAGNOSIS
A 12-year-old female patient, with no relevant clinical record, with retained growth, came for orthodontic consultation with the following reason: "My teeth are coming out at the top".
On clinical examination the patient presented normal development, with a dolichofacial biotype, convex profile, enlarged lower facial third, facial midline coinciding with the dental midline (Figure 1). Intraoral analysis showed class I molar, class canine not established due to upper ectopic canines, right unilateral posterior crossbite, lower incisors proclined and protruded, triangular-shaped upper arch and ovoid-shaped lower arch, inferior midline deviation 2 mm to the left, overjet 3 mm and overbite 3.5 mm (Figure 1), maxillary and mandibular arch length discrepancy, (-9.8 mm and -10.9 mm, respectively), curve of Spee of 2 mm (Figure 2). Radiographically, the patient presented permanent dentition, semipermeable turbinates, condylar asymmetry, presence of third molar germs and lower premolars without apical closure. The lateral cranial radiography showed patent airways and lip incompetence (Figure 3). The Steiner analysis was performed with Dolphin 9.0 software and resolved in a class II skeletal with posterior mandibular rotation (Table 1). Functional analysis showed no alterations in the temporomandibular joint or habits.
Objective: uncross the right unilateral posterior crossbite, correct the overjet and overbite, eliminate Spee's curvature; maintain class I molar; establish class I canine; eliminate crowding, root parallelism; improve function and profile; obtain adequate anterior guidance and arch shapes.
TREATMENT PLAN AND PROGRESSION
The treatment plan started with upper and lower first premolars extractions. Upper and lower bands were placed with lingual boxes to create a transpalatal and lingual arch. Roth slot 0.018" brackets were placed.
Alignment and levelling phase: 0.016" thermal archwires, 0.016" stainless steel (SS), 0.016" × 0.022" thermal archwires were used. Work phase: 0.016" × 0.022" SS, 0.017" × 0.025" SS archwires. Retraction of upper and lower canines was carried out with laceback (Figure 4). The spaces were closed with chain, the midline was corrected and arches were coordinated.
Detailing and finishing phase: once the spaces were closed, panoramic radiography was requested to assess root parallelism and the brackets were repositioned on the dental organs 15, 12, 22, 25 and 45, and the transpalatal arch was removed (Figure 5). Tubes were placed in lower second molars, ¼" 4.5 oz posterior seating elastics were used and the lingual arch was removed (Figure 6). Once the objectives were achieved, the brackets were removed (Figure 7).
Retention: impressions were taken for the fabrication of upper and lower circumferential retainers. The patient was referred for third molar surgery.
RESULTS
Right unilateral posterior crossbite and crowding was eliminated, class I canine was established; class I molar was maintained; adequate overjet and overbite, curve of Spee correction and adequate shape of the dental arch were obtained; crowding was eliminated. Adequate seating of the occlusion with anterior guidance was achieved and the profile was improved by decreasing facial convexity. In addition, periodontally the gingival margin of the canines was in good position (Table 1) (Figures 7 and 8).
DISCUSSION
Dental crowding and lack of space are the main problems in the present case; we agree with Jacoby who reported that only 17% of subjects with ectopic displacement of canines had sufficient space for eruption in the arch.12 Similarly, tooth size and dental arch dimensions are determining factors in dental crowding.13
Rodríguez et al mention that the term anchorage is understood as the resistance required to mobilize the teeth and then control the counterforces, which in turn will depend on: the number and length of the roots involved, the axial position of the teeth to be anchored and the bony structures surrounding the teeth.14 In the present case, anchorage was necessary, as maintaining the class I molar was an objective, as well as the extraction of upper and lower first premolars for the correct placement of the ectopic canines, in both arches.
Carlton and Nanda concluded that, with orthodontic treatment, the condyles are positioned more concentrically and that the anterior and posterior joint spaces changed significantly in most cases in patients treated with premolar extraction.15 In contrast, other studies concluded that condylar position was stable during treatment and did not behave differently under extraction and non-extraction conditions.16,17 We agree with the latter, because the patient presented stability during orthodontic treatment and after premolar extraction.
The treatment objectives in malocclusions class II are aimed at transversal correction and solving problems of dental crowding (dental alignment), correction of the facial profile with upper and lower first premolars extractions;18 consequently we set such objectives for the correction of class II.
The literature has mentioned and orthodontists have shown that therapeutic premolar extractions are accompanied by changes in the profile and soft tissues,14 as well as improvement in the patient's facial profile.
CONCLUSIONS
All cases are a challenge for orthodontists, because their aim is to create functional, stable and harmonious smiles. To achieve this, full knowledge of the case and the cooperation of the patient is necessary. Space management was fundamental to obtain excellent results with our patient. The first premolars extraction allows the objectives to be met, and as a result the necessary space is obtained for the placement of the ectopic canines and the correction of the incisors proclinations and protrusions. In addition to retracting the anterior segment and causing the mandible to rotate in a counterclockwise direction, class II skeletal problems are solved and the profile is improved.
REFERENCES
AFFILIATIONS
1 Alumna de la Especialidad en Ortodoncia. Departamento de Clínicas Odontológicas Integrales. Centro Universitario de Ciencias de la Salud. Universidad de Guadalajara, México.
2 Egresado de la Especialidad en Ortodoncia. Departamento de Clínicas Odontológicas Integrales. Centro Universitario de Ciencias de la Salud. Universidad de Guadalajara, México.
3 Docente de la Especialidad en Ortodoncia. Departamento de Clínicas Odontológicas Integrales. Centro Universitario de Ciencias de la Salud. Universidad de Guadalajara, México.
CORRESPONDENCE
Dra. Alejandra Noemí Paz Cristóbal. E-mail: ale.ortho@hotmail.comReceived: Marzo 2021. Accepted: Junio 2021.