2020, Number 1
Orthodontic management of a patient with class I malocclusion, anterior cross bite, increased lower face height and double dental protrusion treated none-extractions
Full text
Language: English/Spanish [Versión en español]
References: 22
Page: 23-32
PDF size: 354.85 Kb.
ABSTRACT
This article reports the orthodontic diagnosis and treatment planning of a 17-year-old female patient with aesthetic and functional problems. The patient presented Angle class I malocclusion, anterior crossbite, double incisor protrusion and lip incompetence, as well as a slightly concave straight facial profile. The goals were to maintain vertical control, improve facial aesthetics, eliminate crowding and correct the anterior crossbite. Non-extraction orthodontic treatment was performed. The crossbite was corrected by interproximal reduction and mechanical forces through intermaxillary elastics, which contributed to the alignment and levelling of the teeth, and improving the patient's facial profile.INTRODUCTION
The decision to perform orthodontic treatment with or without extractions of sound teeth is often a complicated one. Factors contributing to the decision making process include the amount of crowding present, the predicted effect of treatment on labial protrusion, the amount of overbite present and the periodontal status of the patient, among others.
Extraction or non-extraction therapy has received much attention from the orthodontist. In particular, the "no extractions at any cost" procedure enunciated by Angle has been replaced by "extractions if necessary" proposed by Case.1 There are different criteria for the orthodontist to avoid extractions. However, a fundamental one is that there must be a class I maxillomandibular relationship, which facilitates orthodontic treatment.2 Similarly, analysis of the patient's facial profile facilitates orthodontic treatment. Knowing the different biomechanics, we have to solve cases that are on the borderline between extractions and non-extractions will help us to be resourceful in order to adapt them to the patient's needs. The use of interproximal enamel wear is an excellent tool to free up space in cases of mild crowding and edge-to-edge overbite correction. The amount of wear is directly related to the amount of crowding to be resolved and its indications are to remove only 1 mm in anteriors (0.5 mm per proximal surface).3-5
The purpose of this case report is to show the orthodontic management of a patient who presented with an anterior crossbite with lower third crowding and biprotrusion, treated with interproximal wear.
CLINICAL CASE
To correct the overbite, intermaxillary elastics were used to correct the overbite. This is an essential material in the treatment, with multiple clinical applications, including, among the most common, that of correcting discrepancies in the anteroposterior direction. The indications for mechanical treatment with CIII elastics are that the force should be approximately 180 g with rigid rectangular arches to avoid unwanted side effects.3
Female patient aged 17 years and four months, who attended the Orthodontic Clinic of the Autonomous University of Baja California campus Tijuana. The reason for her consultation was "I want to fix my smile". The clinical history describes her as an apparently healthy patient. On clinical inspection, a dolichofacial biotype was observed; straight profile; oval, symmetrical facial shape; non-coincident facial and lower dental midline; enlarged middle third; medium-sized lips and lip incompetence (Figure 1).
The intraoral clinical evaluation reported: class I molar and class III canine relationship bilaterally; supraocclusion of the upper canines with presence of moderate crowding; anterior crossbite of the dental organs #22 and 3; lower midline deviated to the left side; lack of coordination of the arches: the lower arch with an ovoid shape and the upper arch with a square shape (Figure 2).
Panoramic radiographs showed 28 erupted permanent teeth and erupting third molars; root length is 3:1; sinuses, condyles and mandibular branches apparently symmetrical, without any alteration (Figure 3A).
On the lateral skull radiograph –according to the Steiner cephalometric tracing– the patient showed a class I skeletal pattern. The enlarged mandibular plane indicates a vertical growth pattern, proinclination of upper incisors (1s/SN 109o) and proinclination of lower incisors (IMPA 94o) (Figure 3B).
TREATMENT OBJECTIVES
- 1. Improve profile.
- 2. Correct anterior crossbite.
- 3. Maintain class I molar relationship on both sides.
- 4. Establish bilateral class I canine relationship.
- 5. Correct horizontal and vertical overbite.
- 6. Release crowding.
- 7. Harmonize both arches.
- 8. Obtain a functional occlusion.
- 9. Maintain periodontal health.
TREATMENT PLAN
On frontal evaluation, the patient showed an inharmonious and proportional face. She presented a straight profile, which is complicated given that it has been proposed that the straight profile could become more concave with time in patients who have not yet completed their growth at the mandibular level.5 For this reason, therapeutic treatment without extractions was used; in addition, interproximal wear was performed to retroclinate the incisors with the use of elastics with a class III force vector plus an anterior vertical vector, which helped the patient to improve her profile.
The patient presented Angle class I malocclusion, with anterior crossbite of the upper left central and upper left lateral incisors. The diagnosis was made based on the aesthetic characteristics, age and type of malocclusion. The treatment was carried out with upper and lower fixed appliances according to the Ricketts' perspective, with 0.018" single slot brackets; alignment and levelling was started with 0.016" round nitinol archwires. The upper left lateral incisor was not ligated from the arch because there was not enough space, so interproximal attrition was performed during the incisor alignment phase, to achieve harmonisation of the arch circumference and contribute to a retroinclination of protrusive teeth to achieve normality (Figure 4).6
At seven months, once sufficient space was obtained, the upper left lateral incisor was incorporated into the arch. After 10 months of treatment, the formation of the upper anterior segment began and the fixed appliance was completed in the lower arch. Interproximal wear was performed to start the alignment and levelling phase in the lower arch. It was decided to place palatal reminders on the upper incisors to avoid open bite by lingual projection (Figure 5).
Once the alignment and levelling was completed in both arches, it was necessary to take a panoramic radiograph and control models to evaluate the root parallelism. After repositioning the brackets, the root was re-leveled with 0.017" × 0.025" rectangular nitinol archwires. Subsequently, 0.017" × 0.025" stainless steel archwires were placed and the bite was finished by seating the bite with 5/16" class III elastics with a force of 4.5 oz in conjunction with 3/16" 6 oz triangular elastics in the anterior segments (Figure 6).
TREATMENT RESULTS
Post-treatment records showed that the treatment goals were achieved. Facial photographs showed improved aesthetics in profile (Figure 7).
Lip incompetence was eliminated, acceptable overbite and intercuspidation were achieved. The midline deviation was corrected and the dental midlines were aligned with the facial midline. Anterior crossbite was eliminated and posterior occlusal relationships were improved with an adequate buccal overjet. class I canine and class I molar relationships were established (Figure 8).
Post-treatment orthopantomography showed adequate spacing and root parallelism with no significant signs of bone or root resorption. The post-treatment cephalogram shows the results obtained, corroborated by the superimposition of the traces (Figures 9 and 10).
DISCUSSION
Orthodontic treatment carried out without extraction tends to be selected as an alternative to avoid the negative effect of a concave/straight profile. Auxiliary devices, such as class III elastics,7 have been used, which contribute to a distal inclination of the mandibular molars in conjunction with straightening of the mandibular incisors and counterclockwise rotation of the occlusal plane, resulting in the correction of horizontal overbite and molar relationships. However, these treatment strategies require the cooperation of the patient, which means that it is often difficult to use such auxiliary attachments in their care. In our case, they worked very effectively so that the proposed orthodontic treatment goals were achieved. Complementing treatment with interproximal wear makes it possible for orthodontists to avoid having to extract teeth,8 as in this report. It is relevant because a large percentage of adult patients have profiles with some level of aesthetic compromise. Such is the case with double protrusion of teeth. When these patients have a healthy periodontium and moderate crowding of about 8 mm, extraction becomes the method of choice to obtain the necessary space towards tooth alignment. In addition, interproximal reduction has also been shown to decrease treatment time in cases of tooth discrepancy which, in turn, allows the inclination of the lower incisors to be maintained and thus prevents proinclination during treatment. Some authors have compared treatment with extractions and posterior anchorage loss with interproximal reduction treatment, where it was shown that there were no significant differences in skeletal changes, but there were significant differences in soft tissue changes. The extractions group showed slightly retruded lips compared to the interproximal attrition treatment.8,9 On the other hand, interproximal attrition may improve post-treatment tooth stability due to the increased contact areas between the teeth,9 although it has been used for years as a treatment for post-treatment tooth irregularity.
Sheridan,3 demonstrated that interproximal reduction can be performed not only on the anterior teeth, but also on the posterior sectors of the arch. This makes interproximal reduction a viable alternative to the extraction of permanent teeth in borderline cases. Interproximal wear therapy has become a reliable tool that orthodontists can use to avoid increasing the intercanine distance or to prevent excessive proinclination of the lower incisors via the labial approach. When the patient was evaluated at the end of the treatment, a better inclination of the position of the lower incisors was observed, achieving a better balance of their profile thanks to the interproximal reduction. This has been shown to be an alternative therapy and to have a good prognosis for patients on the borderline of extraction or non-extraction treatment, and is consistent with other studies reported in the literature.10,11
Most studies emphasise correct diagnosis and planning when deciding on orthodontic treatment with or without extractions, highlighting the importance of whether or not to perform conservative procedures and the effects these would have on the patient's facial profile. Extraction is not only due to lack of space, but also to all the factors that influence a proper diagnosis such as the amount of crowding, the predicted effect of treatment on lip protrusion, the amount of horizontal and vertical overbite present and the periodontal status of the patient.
CONCLUSION
Treatment with interproximal reduction in this patient achieved stable functional occlusion and facial balance.
REFERENCES
AFFILIATIONS
1 Universidad Autónoma de Baja California (UABC) campus Tijuana; Centro Universitario de Posgrado e Investigación en Salud. Tijuana, Baja California.
2 Universidad Autónoma Metropolitana Unidad Xochimilco (UAM-X). México.
CORRESPONDENCE
José Luis Pérez Vázquez. E-mail: jl.perezvaz001@gmail.comDaniel Cerrillo Lara. E-mail: danielcerrillo@uabc.edu.mx
Received: Diciembre 2019. Accepted: Marzo 2020.