A transdisciplinary approach for treatment of class III malocclusion

Abstract

The main aim of orthodontic treatment is to achieve most stable, functional, and esthetic outcome either by conventional, interdisciplinary, or surgical protocol. Treatment modalities differ for growing and nongrowing patients. In nongrowing patients with moderate to severe dental and skeletal deformities, interdisciplinary treatment combined approach is required with orthodontics and orthognathic surgery. Case discussed here is of class III skeletal bases with orthognathic maxilla and prognathic mandible having anterior crossbite with a horizontal growth pattern treated by transdisciplinary approach with combination of orthodontics, orthognathic surgery, and prosthetic approach to get best achievable results of skeletal class III malocclusion.

Introduction

The main goal of orthodontic treatment which could be either conventional, interdisciplinary, or surgical protocol is to achieve stable, functional, and esthetic results. Treatment options differ for a growing and a nongrowing individual. In nongrowing patients, if there is moderate to severe dental and skeletal deformities then it usually requires interdisciplinary treatment combined with orthodontics and orthognathic surgery.[1,2]

Class III malocclusion can be characterized by presenting a mandibular skeletal protrusion (mandibular prognathism), a maxillary skeletal retrusion, a combination of both, or no anteroposterior skeletal imbalances.

Here, we are presenting a transdisciplinary case of class III malocclusion treated by combination of orthodontics, orthognathic surgery, and prosthetic approach to get most achievable results.

Diagnosis and treatment plan

A 29-year-old male patient reported to the OPD of orthodontics department with the chief complaint of forwardly placed lower front teeth and prominent chin. On extraoral examination, patient had a straight profile with slight anterior divergence, obtuse nasolabial angle, increased lower facial third, and protrusive lower lip [Figure 1]. On intraoral examination, patient had proclined maxillary and mandibular incisor with missing 36 and 46, mutilated molar relation, class III canine relation on both sides, reverse overjet and overbite and lower midline shifted to the left by 5 mm [Figure 2]. On radiological examination, the patient was having class III skeletal bases with orthognathic maxilla and prognathic mandible, anterior crossbite with a horizontal growth pattern. Orthodontic records were prepared.

Figure 1.

Extraoral frontal pretreatment photograph

Figure 2.

Intraoral frontal pretreatment photograph

Treatment objectives

Correction of inclination of upper and lower anterior teeth, prognathic mandible, prominent chin, anterior crossbite, reverse overjet and overbite, class III canine relation on both sides, midline and prosthetic rehabilitation irt 36, 46.

Treatment progress

Based on diagnosis and cephalometric data, decision was made to proceed with fixed orthodontic appliance followed by orthognathic surgery BSSO (mandibular setback) and prosthetic rehabilitation for missing lower first molars. Treatment started with MBT 0.022” bracket system. Initial alignment and leveling was started with round 0.014” Niti in upper and lower arches for first visit. 0.014” wires were subsequently replaced with 0.016” and then 0.018” Niti wires in next 2 months. Later on, first rectangular wires have been placed which were 0.017” × 0.025” Niti followed by 0.019” × 0.025” Niti and lastly with 0.019” × 0.025” stainless steel wires. Case was reevaluated mid-treatment for possibility of extraction and to decompensate upper and lower dentition for surgical procedure. Treatment proceeded non-extraction due to patient's straight profile. After completion of decompensation, 0.021 × 0.025” steel wires with surgical hooks were ligated in both arches. At this point of time, patient was ready for orthognathic surgery. Mandibular setback surgery was planned for correction of anterior crossbite and lower midline. [Figure 3] After surgery, another 6 months were taken for post-surgical orthodontics for finishing and detailing and prosthetic rehabilitation [Figure 4].

Figure 3.

BSSO (mandibular set back) surgery

Figure 4.

Post-surgery intraoral frontal photograph

Treatment Results

The well-planned transdisciplinary treatment showed good functional and esthetic results. Posttreatment orthodontic records shows dramatic improvement in facial esthetics primarily due to retraction of mandible. Facial profile pictures show that patient now has orthognathic profile with reduction in chin protrusion [Figure 5]. Posttreatment intraoral pictures and casts demonstrate fixed partial denture in both lower right and left side with good interdigitation of teeth, improvement in negative overjet and also overbite. The ANB angle increase from -4° to +3° and mandibular length decreased from 57 mm to 49 mm. Superimposition of pre and posttreatment cephalometric tracings confirmed the improvement in mandibular positioning and lower-lip posture after the setback surgery [Figure 6a].

Figure 5.

Post-surgery extraoral profile photograph

Figure 6.

(a) Posttreatment lateral cephalogram. (b) Posttreatment intraoral frontal photograph

Prosthetic phase

Patient was then referred to the Department of Prosthodontics and crown and bridge for replacement of missing lower first molars. Due to financial problems, patient was not ready for prosthetic implants and chose for fixed partial dentures for both sides. Once the prosthetic rehabilitation was done, patient was satisfied with his overall esthetics [Figure 6b]. Retention plan involved the use of fixed lingual retainers for both arches.

Discussion

With the surgical repositioning of the mandible for the correction of a prognathic mandible as in skeletal class III patients, the technique for the surgical correction of dentofacial deformities has developed into a well-defined science and a fascinating art form. Currently the most popular surgical procedure for the correction of dentofacial deformities is bilateral sagittal ramus osteotomy involving the correction of skeletal mandibular discrepancy.[3]

Using this surgical protocol, the present transdisciplinary case report describes the management of mild skeletal Class III malocclusion with orthognathic surgery and prosthetic rehabilitation in concurrence with fixed orthodontic appliance. Although skeletal class III malocclusion is usually easy to recognize, but it frequently leads to conspicuous impairment of facial esthetics and depending on the severity may cause gross reduction in masticatory performance.[4]

So to overcome this problem, decompensation was carried out in both the arches, followed by bilateral sagittal split osteotomy which caused counterclockwise rotation of the mandible and enhanced dental and skeletal relationship. A positive overjet was achieved with correction of lower midline and missing both lower first molars were effectively replaced by fixed partial denture.

The combined surgical-orthodontic and prosthodontic treatment of this case led to a significant facial, dental, and functional improvement. Facially, vertical balance and harmony were obtained and this is perhaps the most important goal achieved because it was the patient's chief concern.

Skeletal relapses arising from orthognathic surgery occur in the first months after surgery.[5] Most of the soft tissues changes occur 1 year after surgery, but changes may occur upto 5 years after surgery.[6]

The importance of this clinical knowledge in primary care is that being a clinician we should timely diagnose and intercept adult patient problem correctly in the very first appointment. The treatment to be performed should be without any confusion whether to choose between conventional orthodontic treatment or surgery which is in the best benefit of the patient.

Conclusion

With the cumulative approach we can achieve an adequate balance between both skeletal and dental structures, thereby ensuring satisfactory and healthy functioning of the stomatognathic system's physiological routine.[7] Along with this, optimal facial, oral, and dental esthetics, resulting in a long-term stability can also achieved.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.