Orthognathic treatment for a patient with facial asymmetry associated with unilateral scissors-bite and a collapsed mandibular arch

Bilateral Scissor Bite Treated by Rapid Mandibular Expansion Following Corticotomy

“…The methods reported include the combined use of a mandibular expansion appliance for the mandibular dental arch with contraction of the maxillary dental arch using cross-elastics 10) ; reduction of the maxillary arch and expansion of the mandibular arch using cross-elastics 2) ; reduction of the maxillary arch by using a bonded constriction quad-helix appliance together with expansion of the mandibular arch using a bi-helix appliance 8) ; surgical constriction of the maxilla to correct excess width 11) ; mandibular expansion by posterior subapical mandibular surgery and the use of a lingual arch appliance 12) ; and mandibular widening by distraction osteogenesis 5) . The basic treatment mechanisms thus comprise contraction of the width of the maxillary arch and expansion of the width of the mandibular arch.…”

“…In addition, when such an approach is adopted in adults, the stress associated with expansion is concentrated in the tooth cervix, and this is known to cause alveolar bone loss with the concomitant risk of tooth root exposure, hyperesthesia, and root surface caries 9) . These issues may be resolved by posterior subapical mandibular surgery 12) or mandibular widening by distraction osteogenesis 5) . Posterior subapical mandibular surgery is known to involve risks of injury to the alveolar neurovascular bundle, however, and sufficient vascular supply to the dissected segment is crucial in achieving a good treatment outcome 12) .…”

“…These issues may be resolved by posterior subapical mandibular surgery 12) or mandibular widening by distraction osteogenesis 5) . Posterior subapical mandibular surgery is known to involve risks of injury to the alveolar neurovascular bundle, however, and sufficient vascular supply to the dissected segment is crucial in achieving a good treatment outcome 12) . In distraction osteogenesis, new bone is formed and inter-molar and inter-canine distances remain stable after expansion 5) .…”

“…A number of methods are available for expanding the mandibular arch, and these include the use of cross-elastics 2,10) a bi-helix 8) , a lingual arch 12) , and surgery 5,12) . The use of cross-elastics necessitates strong patient cooperation.…”

Severe unilateral scissor bite and bimaxillary protrusion treated by horseshoe Le Fort I osteotomy combined with mid-alveolar osteotomy

“…However, when multiple teeth are involved in the scissor bite and when the overbite is deep, orthognathic surgery may be indicated if the occlusal contacts interfere with nonsurgical bite opening and prolong the treatment period for scissor bite correction. Although previous reports have shown segmental osteotomy 1 and posterior subapical mandibular surgery 2 to be effective in resolving scissor bite, there are few case reports describing alternative scissor bite treatments because of the rarity of this condition. In particular, no study has reported the efficacy of combining three orthognathic surgical techniques for the treatment of scissor bite.…”