Miniscrew-assisted multidisciplinary orthodontic treatment with surgical mandibular advancement and genioplasty in a brachyfacial Class II patient with mandibular asymmetry

This article describes the complex dental treatment of a 43-year-old man with skeletal Class II, mandibular asymmetry, severe brachyfacial pattern, Class II Division 2, canting of the occlusal plane, and an increased curve of Spee. To achieve optimal results, we adopted a multidisciplinary approach to treatment, involving periodontics, oral surgery, orthodontics, maxillofacial surgery, and prosthetics specialists. After periodontal treatment, miniscrews were placed to correct the occlusal plane canting and the excessive curve of Spee with orthodontic treatment. The surgical treatment plan consisted of a bilateral asymmetric sagittal split osteotomy for mandibular advancement and genioplasty. The patient had an infection after the surgery at the site of the right fixation plate, so the plate was removed, and active orthodontic treatment was continued and finished. Mandibular first molar implants and maxillary ceramic crowns using the Digital Smile Design method (Digital Smile Design, Doral, FL) were placed at the end of orthodontic treatment. The patient was satisfied with the treatment results and with his facial and dental appearance, as well as his oral function. The 2-year follow-up pictures show a stable result both esthetically and functionally.

Highlights

  • Adults with skeletal and dental problems require a multidisciplinary approach.

  • Miniscrews used as auxiliary elements shorten preoperative treatment.

  • Miniscrews can correct occlusal plane canting and excessive curve of Spee easily.

  • Orthognathic surgery has risks sometimes requiring reoperation to remove plates.

  • After mandibular advancement surgery, the volume of the pharyngeal airway increases.

Demand for facial and dental esthetic procedures by adults is growing. Most of these patients have more than 1 oral problem: eg, periodontal disease, caries, missing teeth, distressed crowns, and different restorations. Because of these concomitant issues in many adults seeking orthodontic treatment, the intervention of different specialists (eg, periodontist, oral and maxillofacial surgeon, prosthodontist, orthodontist) may be required to ensure esthetic and functional results.

The treatment of nongrowing skeletal Class II patients frequently consists of a combination of orthodontic and orthognathic surgical procedures. In most cases, the aims of these procedures are not only to correct the dental relationship and to harmonize function but also to improve facial esthetics. Genioplasty is often conducted in combination with mandibular advancement when patients have a flat or insufficient labiomental fold requiring greater chin projection. But in most Class II Division 2 patients with severe deep overbite, the chin is overprojected, so a chin setback osteotomy is often required.

Numerous studies have investigated the effects of craniofacial morphology (facial pattern) and skeletal class on the posterior airway space. Some studies have shown that bilateral mandibular advancement surgery in Class II patients leads to significant increases in posterior airway space volume and significant widening of the narrower sites inside the pharynx.

In addition to a skeletal discrepancy, Class II Division 2 patients generally have multiple dental issues, such as deep overbite due to an increased curve of Spee, retroclination of maxillary incisors, and occlusal plane canting. Correction of occlusal plane canting can be achieved with conventional orthodontic appliances assisted by miniscrews, intruding the teeth on the corresponding side of the dental arch. In some cases, this will avoid LeFort I surgery.

Treatment of Class II Division 2 malocclusion, characterized by retroclination of the maxillary incisors and deep overbite, has been considered challenging because of the difficulty of controlling the orientation of the incisor axis. This makes both the intrusion and the torque control of the retroclined maxillary incisors important treatment objectives. Miniscrews placed in the interradicular areas as anchorage units provide true intrusion of the incisors in patients with deep overbite and prevent unwanted movements to the rest of the teeth; this cannot be achieved by conventional methods.

This case report presents a successful orthodontic and orthognathic surgical treatment of an adult with skeletal Class II Division 2 and a severe brachyfacial pattern. To achieve optimal results, we adopted a multidisciplinary approach to treatment involving periodontics, oral surgery, orthodontics, maxillofacial surgery, and prosthetics specialists. See Supplemental Materials for a short video presentation about this study.

Diagnosis and etiology

A 43-year-old man complained of a poor smile and facial profile esthetics, referring specifically to the marked mentolabial fold and submental fullness. He was also concerned about a snoring problem.

The frontal photograph shows mandibular asymmetry, with the mandible shifted to the right. Maxillary incisal exposure during smiling was considered to be within the normal range, with no exposed gingiva. The lateral photograph shows a concave facial profile, with severe reduction of the lower facial third and overprojected chin ( Fig 1 ).

Fig 1
Pretreatment facial and intraoral photographs.

The molar and canine Angle relationships were complete Class II. Overjet and overbite were 7.2 and 8.0 mm, respectively. The mandibular dentition showed an excessive curve of Spee because of the overerupted incisors. In addition, a canted occlusal plane was present, and the maxillary left first premolar had a scissors-bite. The maxillary dental midline matched the facial midline, whereas the mandibular dental midline deviated to the right because of the asymmetry. The discrepancy index values were –3 and –4.1 mm for the maxillary and mandibular arches, respectively. There were several old single metal-ceramic crowns in both arches. An anterior Bolton ratio discrepancy was present in the maxillary central and lateral incisors ( Figs 1 and 2 ).

Fig 2
Pretreatment dental casts.

The patient had chronic mild periodontitis with bleeding of almost every tooth; the papillae between the maxillary left central and lateral incisor and between the maxillary left lateral incisor and canine were missing because of a deficiency in the adjustment of the old single metal-ceramic crowns ( Fig 1 ).

The cephalometric analysis ( Fig 3 , A and B ; Table ) showed a skeletal Class II (ANB, 3.3°) with a severe brachyfacial pattern (facial axis, 95.4°; FMA, 6.9°; lower facial height, 60.1 mm). The maxillary and mandibular incisors were lingually inclined (U1- palatal plane, 99.8°; IMPA, 92.9°); as a result, the interincisal angle was increased (156.3°). The patient had a narrow middle and lower pharyngeal airway space ( Fig 3 , A ).

Fig 3
A, Pretreatment lateral cephalogram; B, cephalometric tracing; C, panoramic radiograph.

Table
Pretreatment and posttreatment cephalometric summary
Cephalometric analysis Initial Norm Final
SNA angle (°) 84.5 82 83
SNB angle (°) 81.2 80 83
ANB angle (°) 3.3 2 0
Wits appraisal (mm) −0.5 1 −3
U1-palatal plane (°) 99.8 110 115
IMPA (L1-MP) (°) 92.9 95 99.3
Interincisal angle (°) 156.3 130 127
Overjet (mm) 7.2 2.5 2.7
Overbite (mm) 8 2.5 1.8
Facial axis (NABA-PTGN) (°) 95.4 90 91.5
FMA (MP-FH) (°) 6.9 22.9 14.8
Lower facial height (ANS-ME) (mm) 60.1 66.5 67.8
Mandibular length (GO-GN) (mm) 73 83 80.7

The maxillary left central and lateral incisors, the maxillary right first and second premolars and left first premolars, and the mandibular first molars had been treated endodontically, as seen in the panoramic radiograph. Periapical lesions were seen in the mandibular first molars that had old single metal-ceramic crowns. The maxillary third molars had already been extracted by the oral surgeon, whereas the mandibular third molars were still present ( Fig 3 , C ).

Based on these findings, the patient was diagnosed with skeletal and dental Class II Division 2, with excessive overbite and overjet, increased curve of Spee, and occlusal plane canting. Several teeth had old metal-ceramic crowns and had been treated endodontically. Periodontal health and airway space were also compromised.

Treatment objectives

The treatment objectives were (1) to establish a skeletal and dental Angle Class I relationship, (2) to level the occlusal plane and flatten the curve of Spee to achieve a harmonious smile, (3) to obtain a balanced facial profile, (4) to widen the pharyngeal airway space to minimize the snoring problem, and (5) to improve the look and adjustment of the restorations for better periodontal health and a more attractive smile.

Treatment objectives

The treatment objectives were (1) to establish a skeletal and dental Angle Class I relationship, (2) to level the occlusal plane and flatten the curve of Spee to achieve a harmonious smile, (3) to obtain a balanced facial profile, (4) to widen the pharyngeal airway space to minimize the snoring problem, and (5) to improve the look and adjustment of the restorations for better periodontal health and a more attractive smile.

Treatment alternatives

Both surgical and nonsurgical treatment approaches were considered. Nonsurgical treatment or dental camouflage consisting of maxillary arch alignment and occlusal plane leveling, followed by excessive labial tipping of the mandibular incisors to minimize overjet was rejected because this would not improve the patient’s profile (facial esthetics was one of the patient’s major concern). It would also threaten the periodontal health of the mandibular incisors due to excessive proclination, and it would not widen the pharyngeal airway space, which was initially compromised. For all these reasons, orthodontic-orthognathic surgery was planned to fulfill the desired esthetic, functional, and health objectives.

Treatment progress

A treatment plan was developed with a team approach involving orthodontics, periodontics, oral surgery, orthognathic surgery, and prosthodontics.

The treatment comprised 3 phases. The initial phase involved preoperative orthodontic treatment with a preparation time of 10 months. Initially, nonsurgical periodontal treatment (scaling and root planing) was performed by the periodontist based on the premise that orthodontic treatment can lead to irreversible breakdown of the periodontium when active periodontitis is present. At the same time, the mandibular third molars were extracted by the oral surgeon.

Second, the mandibular left first molar was scheduled for extraction by the oral surgeon because of signs and symptoms including pain and a periapical lesion; the right first molar was maintained in the mouth and kept under observation since the patient reported no discomfort or pain. The old distressed single metal-ceramic crowns were replaced by provisional resin crowns, so that the condition of the papillae could improve.

A 0.022 × 0.028-in slot preadjusted edgewise appliance (Victory Series; 3M Unitek, Monrovia, Calif) was placed on the mandibular arch, and a self-ligating 0.022 × 0.028-in slot appliance system (Clarity; 3M Unitek) was used on the maxillary arch. MBT prescriptions were chosen for the appliances in both arches. Orthodontic alignment and leveling were achieved using nickel-titanium 0.014-in, 0.016-in, 0.019 × 0.025-in, and 0.021 × 0.025-in archwires, whereas stainless steel 0.016-in, 0.019 × 0.025-in, and 0.021 × 0.025-in archwires were used to correct the dental arches. Additional torque to the maxillary incisors was necessary, so Warren torquing springs (Rocky Mountain Orthodontics, Denver, Colo) were used in combination with the stainless steel 0.021 × 0.025-in archwires.

One miniscrew (length, 10 mm; diameter, 1.6 mm; Jeil Medical, Seoul, Korea) was inserted into the buccal alveolar bone at the second quadrant between the maxillary left lateral incisor and canine to correct occlusal plane canting ( Fig 4 ), and 2 more were placed in the mandibular incisor area to obtain intrusion of the incisors ( Fig 5 ). Miniscrews were used as direct anchorage units, and force was applied to the archwire with an elastic thread. The screws were placed in the mucosa and inserted in the interradicular areas under local anesthesia at the start of treatment. After 6 months, intrusion of the mandibular anterior teeth was achieved, and the canting of the occlusal plane was corrected, so the miniscrews were removed.

Dec 12, 2018 | Posted by in Orthodontics | Comments Off on Miniscrew-assisted multidisciplinary orthodontic treatment with surgical mandibular advancement and genioplasty in a brachyfacial Class II patient with mandibular asymmetry
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