Orthodontic re-treatment case of a class II skeletal base malocclusion: A case report

INTRODUCTION

An increasing number of patients seeking orthodontic treatment today have a history of prior orthodontic treatment. The reasons for orthodontic re-treatment are multifactorial, such as the desire to achieve better esthetic outcomes and oral function, poor retention compliance, unfavorable skeletal growth pattern, and failure in the initial diagnosis and treatment plan.^[1] Failure to perform orthodontic treatment adequately may result in a poor facial, gingival, and dental outcome as well as prolonged treatment duration and increased risk of damage to teeth, pulp, and supporting tissues.^[2]

In orthodontic re-treatment cases, the orthodontist should assess all potential risk factors before initiating tooth movement, particularly for patients with a history of prolonged previous treatment. Clinical examination, anamnesis, and pre-treatment radiographic evaluation are essential for detecting abnormalities such as root resorption and bone loss.^[3] An orthodontist should conduct a complete periodontal evaluation before initiating orthodontic treatment. Teeth with root resorption should be carefully maintained to prevent the development of periodontal problems. Shortened roots do not increase the risk of complications if the periodontal tissues remain healthy. Therefore, orthodontists should establish a comprehensive re-treatment plan that includes regular monitoring of the involved teeth, proper oral home care, regular periodontal therapy if needed, and continuous patient education about oral health.^[4]

CASE REPORT

A 30-year-old female came to our orthodontic clinic at the dental hospital, Faculty of Dentistry, Universitas Indonesia, in Jakarta, Indonesia. She asked for orthodontic re-treatment due to misalignment and proclination of her teeth after 4 years of previous orthodontic treatment. She also reported mobility in several teeth.

The clinical examination showed a mesofacial, proportional, and symmetrical face. She had a convex facial profile, protrusive upper and lower lips. The intraoral examination showed a fixed appliance in situ with poor oral hygiene, grade two tooth mobility on all teeth except molars, an upper left first molar with pulpal necrosis, and abnormal tooth contour from interproximal reduction. She had a moderate maxillary and mandibular crowding, anterior crossbite with −5 mm overjet, posterior crossbite of right first premolar, Class I canine relationship and Class II half-unit molar relationship on the right. The maxillary dental midline was deviated 1.5 mm toward the left, and the mandibular dental midline coincident with the midfacial axis [Figure 1]. The root apices of the upper right lateral incisor to the upper left lateral incisor were palpable from the labial gingiva. There were no complaints of pain or restriction during jaw opening and closing.

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Figure 1:

(a-c) Pre-treatment facial photographs: frontal, smiling and profile views; (d-h) Pre-treatment intraoral photographs: right buccal, frontal, left buccal, maxillary occlusal and mandibular occlusal views.

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The initial lateral cephalometric radiograph showed a class II skeletal pattern with bimaxillary prognatism, vertical growth pattern, convex skeletal profile, retroclined upper incisors, and proclined lower incisors. Moreover, the initial panoramic radiograph showed horizontal alveolar bone loss in certain areas, multiple root resorption, an impacted lower left third molar, and several mandibular tooth apices were not seen in the radiograph [Figure 2].

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Figure 2:

Pre-treatment radiographs and tracing. (a) Panoramic radiograph. Red arrow indicates a representative area of apical root resorption; (b) Lateral cephalometric radiograph; (c) Cephalometric tracing. Blue arrow indicates severe lower incisor proclination. R: right; L: left.

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Treatment results

The final result showed that the patient had an improved facial profile with resolution of her chief complaint. Good interdigitation with healthy periodontal tissue was obtained. Normal overjet and overbite were achieved along with alignment of the dental midline with the facial midline, and the posterior crossbites were corrected. Competent lips and a favorable incisor display when smiling were achieved [Figure 3]. Good root parallelism was achieved at the end of treatment. At debonding, there was no concerning periodontal problem and no additional periodontal treatment was required after orthodontic therapy.

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Figure 3:

Post-treatment facial photographs: (a-c) Frontal, smiling and profile views; post-treatment intraoral photographs: (d-h) Right buccal, frontal, left buccal, maxillary occlusal and mandibular occlusal views.

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Analysis on the lateral cephalometric radiograph showed improvement of the maxillary incisor to maxillary plane angle (upper incisor to maxillary plane (UI-MxP)) from 90° to 108° and the mandibular incisor to mandibular plane angle (lower incisor to mandibular plane (LI-MdP)) from 138° to 105.5°. Soft-tissue parameters showed improvement of the positions of the upper and lower lips [Table 1 and Figure 4]. Those changes were confirmed by the superimposition of the cephalometric radiograph tracings [Figure 5].

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Figure 4:

Post-treatment radiographs and tracing. (a) Panoramic radiograph; (b) Lateral cephalometric radiograph; (c) Cephalometric tracing. Blue arrow indicates the correction of the previously severe lower incisor proclination. R: right; L: left.

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Figure 5:

Superimposition of cephalometric tracings. (a) Sellanasion plane; (b) Palatal vault and zygomas; (c) Inner surface of the mandibular symphisis and mandibular canal outline. Black: pre-treatment; Red: post-treatment.

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Table 1: Cephalometric measurements.

Parameters	Norms (Mean± Standard Deviation)	Initial	Predebonding
Horizontal skeletal parameters
SNA (°)	81±3	90	91
SNB (°)	78±3	84	85
ANB (°)	3±2	6	6
Wits appraisal (mm)	0±2	−2	1
Facial angle (°)	87±3	87	88
Angle of convexity (°)	0±10	11	13
Vertical skeletal parameters
y-axis (°)	60±6	65	64
Go-angle (°)	123±7	125	122
SN-MdP (°)	32±3	30	30
MMPA (°)	27±4	32	32
Dental parameters
Interincisal angle	135±10	105	112
UI-MxP (°)	109±6	90	108
UI-NA (mm)	4±2	12	4.5
LI-MdP (°)	90±4	138	105.5
LI-NB (mm)	4±2	18	9
Soft tissue parameters
Upp lip-E- Line (mm)	1±2	2.5	1
Low lip-E- Line (mm)	0±2	6	3

SNA: Sella-nasion-A point, SNB: Sella-nasion-B point, ANB: A point-Nasion-B, SN-MdP: Sella-Nasion-mandibular plane, MMPA: Maxillo-mandibular plane angle. UI-MxP: Upper incisor-maxillary plane; UI-NA: Upper incisor-Nasion-A point; LIMdP: Lower incisor-mandibular plane; LI-NB: Lower incisor-Nasion-B point.

DISCUSSION

Various difficulties in the orthodontic treatment can arise from inappropriate treatment strategies, poor treatment execution, and ineffective communication with the patient. These shortcomings can significantly affect treatment outcomes and their long-term stability.^[2] Poor treatment was the main reason for the failure of the original treatment in patients seeking orthodontic re-treatment. An orthodontist must have a thorough understanding of the factors that contributed to the initial failure.^[1] In this case, an anterior crossbite was developed in a class II skeletal base, accompanied by tooth mobility, significant bone loss, and apical root resorption.^[3] These complications were likely due to inappropriate treatment strategies, such as incorporating excessive use of elastic chains in flexible nickel–titanium wire, incorrect bracket positioning, inadequate oral hygiene management, and prolonged treatment duration in the previous treatment. Excessive force application has been associated with adverse effects, including root resorption, anchorage loss, tooth mobility, and bone loss, especially in patients with poor oral hygiene.^[3]

The etiology of external apical root resorption is multifactorial, such as root morphology and orthodontic treatment-related variables, such as the severity of the malocclusion, duration of orthodontic treatment, bracket system, mechanics used, and the magnitude of orthodontic forces.^[7,8] In this case, root resorption was more evident in the maxillary anterior region, probably caused by heavy orthodontic forces in the previous treatment. Moreover, the use of a conventional bracket system and prolonged duration of previous orthodontic treatment may also have contributed to this condition. However, research suggests that root resorption is influenced more by the duration of treatment than by the bracket system used.^[7,8]

Orthodontic treatment should be delayed until any active periodontitis has been controlled. Untreated periodontal inflammation may contribute to the progression of the underlying condition. Moreover, inadequate treatment planning, poorly controlled mechanics, and the use of excessive forces may increase the risk of localized or more generalized exacerbation of existing periodontal issues.^[9] In this case, the patient initially referred to a periodontist to eliminate active periodontal disease and to establish proper oral hygiene habits. After periodontal pocket assessment and scaling, the patient was confirmed to be free of active periodontal disease and was then cleared to proceed with orthodontic treatment.

In orthodontics, extracting permanent teeth is a common strategy to correct a Class II malocclusion. The decision to extract should be based on a proper diagnosis that considers both occlusal outcomes and the patient’s facial profile.^[10] In some cases, a non-extraction approach may be preferred, particularly when dental compensation can achieve functional occlusion without compromising facial esthetics. Extraction therapy, particularly the removal of maxillary first premolars, has long been indicated for patients with significant dental protrusion, allowing anterior retraction and improvement of facial esthetics.^[11] However, in this orthodontic re-treatment case, extraction planning becomes more complex, requiring careful evaluation of the remaining dentition, anchorage availability, and restorative plans.^[12] The maxillary left first molar was extracted because the tooth was severely damaged. Although it is not a common choice for extraction, first or second molar extraction can be justified if the third molars are healthy and in good position with proper size and shape.^[10]

A treatment plan involving extractions could give a higher biological cost for this patient, considering her existing root resorption, bone loss, and history of extensive orthodontic treatment. However, extractions were selected because they were considered necessary to achieve the desired improvement in her facial profile. In this case, premolar extractions were intentionally delayed to avoid further retraction of already retrusive maxillary incisors and to prevent additional risk to the periodontal tissue in the upper anterior segment. Alignment and upper incisor torque were corrected first to establish a positive overjet. Once a more favorable incisor position was achieved, premolar extractions were performed. Anchorage management was carefully planned, considering the patient’s conditions. To minimize additional damage to teeth and supporting tissues, a passive self-ligating system was used, as it gives light continuous forces. Early light class III elastics were used to correct the incisors’ inclination while minimizing excessive loading on the posterior anchorage units. Maximum anchorage was reinforced by consolidating the posterior teeth using stainless steel ligatures. Combined with the use of light continuous forces throughout the treatment and gradual space closure, this approach was adequate to maintain posterior anchorage without the need for skeletal anchorage devices.

Passive self-ligating brackets are often promoted for their ability to reduce friction between the archwire and bracket slot compared to conventional brackets, since they do not require steel or elastomeric ligatures. The reduction in friction is believed to enable efficient tooth movement with lighter forces. As a result, several additional advantages have been suggested, including improved bone adaptation, enhanced arch development, reduced anterior proclination, shorter treatment duration, fewer appointments, and reduced chairside time.^[8,12] In addition, self-ligating brackets also may promote better oral hygiene, because the absence of elastomeric ligatures or related auxiliaries makes oral hygiene maintenance easier. This is an important consideration in periodontally compromised patients, especially in patients with poor oral hygiene.^[13] While the evidence remains controversial regarding superiority over conventional appliances, their biomechanical efficiency and hygiene benefits make them a good choice in complex retreatment cases.

This orthodontic re-treatment resulted in improvements in both the patient’s facial profile and occlusion, with a 3 mm increase in the Wits appraisal attributed to occlusal plane correction. Significant dental changes included an 18° increase in the UI-MxP angle and a 22.5° reduction in the LI-MdP angle, indicating maxillary incisor proclination and mandibular incisor retroclination. These changes were essential for correcting the anterior crossbite and enhancing smile esthetics. The maxillary incisor proclination and mandibular incisor retroclination were achieved through the early use of Class III elastics.

In this case, additional retraction in the maxillary and mandibular incisors was needed to improve the facial profile. During maxillary incisor retraction, a 0.017 × 0.025-in accentuated curve stainless steel archwire was used to maintain the incisor inclination and prevent excessive lingual crown tipping. Meanwhile, in the mandibular arch, a 0.018-in stainless steel wire was used to retract the lower incisors to produce greater retroclination. This 0.018-in stainless steel wire is effective in managing severely proclined incisors.^[14] The selective use of working wire sizes and dimensions facilitated the proper establishment of final torque in both maxillary and mandibular anterior teeth, as play increases with greater differences in size between the slot and wire dimensions.^[15] Correct torque control is often required for an ideal interincisal angle, adequate incisor contact, and sagittal adjustment of the dentition to achieve ideal stability, good function, and esthetics, especially in this case where inadequate root positioning persists from prior orthodontic treatment.^[16]

To ensure long-term stability in the case of reduced periodontal support, combining fixed and removable retainers provides greater predictability and stability.^[9] In this case, the patient was instructed to wear the removable retainer full-time (except mealtimes) for the 1^st year and nightwear during the 2^nd year and subsequent years. Long-term retention was advised due to the patient’s condition. Some studies suggested that to ensure satisfactory stability, post-orthodontic treatment is using retainers for life.^[17,18] Furthermore, the patient was also instructed to maintain good oral hygiene and periodontal health with a bonded retainer in place.

CONCLUSION

Orthodontic re-treatment presents challenges that demand a carefully planned, multidisciplinary teamwork to obtain optimal functional and esthetic outcomes. Orthodontic retreatment using light continuous force and an appropriate force system proved effective in managing the complications of previous treatment. Collaboration with a periodontist was essential in establishing a healthy periodontal tissue before initiating orthodontic treatment. Given the complexity of the case, long-term retention was recommended for this patient to enhance long-term stability and minimize the risk of relapse.