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ePaper created 2018-03-13, 09:28:55 | version 1.38.0
| case report Non-surgical treatment of a Class III malocclusion with missing lateral incisors Dr Ana Maria Cantor, Spain Class III malocclusions are classified into four types of skeletal and dental relationships with either (1) mandi- bular protrusion, (2) maxillary retrusion, (3) a combination of the two or (4) a normal relationship of the jaws.1–3 The prevalence of Class III malocclusions is estimated to be 1 to 10 %, depending on ethnicity, sex and age. The aeti- ology may be skeletal or dentoalveolar.4 The incidence of lateral incisor agenesis in the permanent dentition is estimated to be between 1.6 and 9.6 %,5, 6 and there is a correlation between the size of the maxilla and agenesis of maxillary teeth.6 The two possible therapeutic options for adult patients with Class III malocclusions are orthognathic surgery or camouflage orthodontics.7 Regardless of the option chosen, it is important to take into consideration increas- ing the angle of convexity (ANB) to improve the profile of the face with a greater increase in the length of the upper lip.8 It is, however, often difficult to predict the result that can be offset by labial inclination of the maxillary incisors and the subsequent negative effect on the patient’s smile,9 as well as retro-inclination of the mandibular inci- sors, with deleterious effects on the periodontium. The combination of Class III malocclusion with missing maxillary lateral incisors can be challenging to resolve sat- isfactorily while enhancing the facial profile of the patient given the constriction of the maxilla. In patients with these characteristics, a combination of orthognathic surgery and orthodontics with a bridge or implants is often rec- ommended.10 Given that the patient in the following case report would not consider orthognathic surgery or open- ing space orthodontically for the placement of implants, the alternative recommended was camouflage ortho- dontic treatment. The case report is intended to illustrate treatment of a Class III malocclusion exhibiting maxillary lateral incisor agenesis with the use a simple Class III functional appliance for anterior-posterior correction, fol- lowed by fixed self-ligating appliance therapy. Diagnosis and treatment plan A 30-year-old female patient presented with a concave profile and maxillary hypoplasia with a short upper lip and lower retracted labial protrusion, an obtuse nasola- bial angle, and skeletal Class III maxillary retrusion and mandibular protrusion. Dentally, the patient exhibited a Class III malocclusion with marked crowding, an anterior crossbite, a 1 mm midline deviation, a moderate curve of Spee and agenesis of the maxillary lateral incisors that the panoramic radiograph confirmed (Figs. 1a–j; Tab. 1). The treatment goals were to improve the patient’s facial aesthetics, correct the Class III malocclusion exclusively with orthodontics, reduce the concavity of her profile and create greater fullness of the upper lip, correct the ante- rior crossbite, distalise the mandibular posterior seg- ment, protract the maxilla and close the spaces from the congenitally missing lateral incisors, reconstructing the canines as lateral incisors and the first premolars as canines. Since the patient rejected the more invasive options recommended and opted for camouflage ortho- dontics, she was cautioned that a satisfactory result depended on her strict compliance with the treatment protocols, specifically the use of elastics. Wire sequence Treatment followed the Carriere System (Henry Schein Orthodontics) archwire sequence, except in this case the first wire was a 0.016 in. dimension wire rather than a 0.014 in. wire. The archwires were all thermally activated wires, with lower transformation temperatures chosen as archwire sizes increased to limit force on the periodontium: – 0.016 in. Cu Nitanium (27 °C) – 0.014 × 0.025 in. Cu Nitanium (27 °C) – 0.017 × 0.025 in. Cu Nitanium (35 °C) – 0.019 × 0.025 in. Cu Nitanium (35 °C). Treatment progress Treatment commenced with the simultaneous use of a Carriere Motion 3D Class III Appliance (Henry Schein Orthodontics) for sagittal correction and Carriere SLX (Henry Schein Orthodontics) 0.022 in. MBT prescription pre- adjusted, passive self-ligating brackets bonded with 0.016 in. Cu Nitanium archwires engaged in the upper arch for anchorage. The Motion 3D Class III appliance 14 ortho 1 2018