Probable Airway Etiology for a Severe Class III Openbite Malocclusion:
Conservative Treatment with Extra-Alveolar Bone Screws and Intermaxillary Elastics
Drs. Ming-Jen Chang, John Jin-Jong Lin, Roberts WE.
A 20yr female presented with a severe Class III malocclusion, anterior openbite, posterior crossbite, facial asymmetry, and mandibular deviation to the left. Chief concerns were poor esthetics, and compromised occlusal function.
Diagnosis: The bilateral full-cusp (8-9-mm) Class III malocclusion was complicated with maxillary retrusion (SNA 78º), prognathic mandible (ANB -2º), steep mandibular plane (FMA 39.5º), anterior crossbite/openbite, peg-sharped upper lateral incisors, ectopic eruption of the upper right (UR) canine, and a 3-mm lower left (LL) mandibular deviation. The Discrepancy Index (DI) was 62.
Treatment: Most complex functional malocclusions are best managed with conservative (non-extraction and non-surgical) treatment that tends to reverse the etiology of the problem. A full-fixed passive self-ligating appliance with extra-alveolar (E-A) bone screw anchorage was indicated. Since the patient’s lips were marginally competent, the preferred anchorage were three extra-alveolar (E-A) bone screws: right mandibular buccal shelf (MBS), and infrazygomatic crest (IZC), bilaterally. Differential Class III intermaxillary elastics were used to correct the Class III occlusal relationship and midline discrepancy.
Results: Superimposition of cephalometric tracings documented retraction and rotation of the lower arch to correct the Class III discrepancy and the anterior openbite. The mandibular plane remained stable, and dentofacial esthetics were markedly improved, resulting in a Pink & White dental esthetics score of 2. The interdental soft tissue posture and anterior openbite resolved spontaneously as the dental alignment was corrected to an excellent cast-radiograph evaluation (CRE) of 17 points. (Int J Orthod Implantol 2017;45:4-20)
Key words:Self-ligating appliance, IZC (infrazygomatic crest), buccal shelf, miniscrew, open bite, cross bite, midline off, chin deviated, peg laterals, Tomy’s LH (Low Hysteresis) MEAW wire
Protrusive Partially Edentulous Malocclusion: Early Loss of a Lower First Molar, Implant Site Development and VISTA Soft Tissue Augmentation
Drs. Chris Lin, Chang CH, Roberts WE.
Introduction: A 29yr female presented with chief complaints of irregular teeth and a protruded chin. The upper right (UR) lateral incisor (#7) was congenitally missing and #10 was a peg lateral. The lower left (LL) first molar was apparently lost in childhood due to a developmental problem: molar-incisor hypoplasia (MIH).
Diagnosis & Etiology: The probable etiology of the anterior crossbite and midline deviation was the collapse of the left posterior dentition when the second deciduous molar was lost (~age 10-12yr). When there is a loss of posterior occlusal stops in the mixed dentition, children often posture anteriorly to achieve a more comfortable occlusion. Teeth #12 and 15 were subsequently lost to caries, which resulted in additional atrophic extractions sites.
Treatment & Results: The patient preferred conservative treatment with minimal surgery, and no temporary anchorage devices (TADs). Following extraction of an endodontically treated LR5 (#29), both arches were orthodontically retracted for space closure and correction of lip protrusion. The upper left second premolar (UL5) (#13) was translated anteriorly to create an implant site. Subsequently an osseointegrated fixture was placed in the prepared site, along with a simultaneous soft tissue augmentation procedure via the vestibular incision subperiosteal tunnel access (VISTA) technique. The UR canine (UR3) and first premolar (UR4) were reshaped and substituted for the missing lateral incisor and adjacent canine.
Outcomes: Following 42 months of interdisciplinary treatment, this difficult malocclusion with a Discrepancy Index (DI) of 27 was treated to an excellent cast-radiograph (CRE) score of 22. However, the Pink & White dental esthetics score was a relatively high 8 because of esthetic zone problems secondary to a midline discrepancy, that occurred because the patient declined miniscrew anchorage. (Int J Orthod Implantol 2017;45:24-56)
Key words: VISTA, implant site development, connective tissue graft, tuberosity graft, root coverage procedure, patient restrictions on treatment
Convex, Class II, Deepbite, Gummy Smile and Lingually Tipped Incisors: Conservative Correction with Bone Screws and a Crown Lengthening Procedure
Drs. Chang-Kai Chen, Angle Lee, Chang CH, Roberts WE.
Introduction: A 26-year-old female sought orthodontics consultation for nonextraction treatment to correct unsatisfactory facial and dental esthetics. She attributed her concerns to a protrusive upper lip and gummy smile.
Diagnosis Severe facial convexity (28%) and increased lower facial height (57.6%) was associated with a protrusive maxilla (SNA 85º), retrusive mandible (SNB 75º), Class II occlusion, high mandibular plane angle (FMA 33º), 100% deepbite, lingually tipped maxillary incisors (U1 to SN 88º), asymmetric gummy smile, and extrusion of the maxillary incisors.
Etiology: This complex malocclusion was consistent with a functional retrusion and clockwise rotation of the mandible, due to the lingual orientation of the upper incisors (“locked-in bite”).
Treatment:Initial bite opening was with bite turbos on the upper maxillary canines that were then transferred to the adjacent central incisors, after they were aligned. Both arches were aligned with a passive self-ligating (PSL) fixed appliance. Class II correction was accomplished with intermaxillary elastics, and osseous anchorage provided by maxillary bone screws, placed apical to the incisors and buccal to the molars. Following alignment, surgical crown lengthening was performed in the maxillary anterior segment, and 6 months later the gingival contours were refined with a diode laser. Result: Facial esthetics were improved by decreases in facial height (5º) and facial convexity (3%), as well as correction of the asymmetric gummy smile and lip competence. In 30 months, this severe malocclusion, with a Discrepancy Index (DI) of 27, was treated to an excellent Cast-Radiograph Evaluation (CRE) of 24, and a pleasing Pink & White Esthetic Score of 3. The facial and dental results were stable at the six month follow-up evaluation. (Int J Orthod Implantol 2017;45:60-81)
Key words: Asymmetry, Gummy smile, deepbite, Class II malocclusion, self-ligating brackets, bite-turbos, temporary anchorage devices, arch retraction, surgical crown lengthening, infrazygomatic crest, extra-alveolar, bone screws
Archwire Sequence for a Passive Self-Ligating Lingual Bracket System with an 0.018-in Square Slot
Drs. Angle Lee, Chang CH, Roberts WE.
Archwire sequencing is the key to efficient treatment with an advanced lingual bracket system. To ensure patient comfort, maximize the potential for each phase of treatment, and progress to the final archwire as soon as possible, clinicians must carefully sequence the mechanics in a specific order. There are four stages for comprehensive orthodontic treatment: (I) alignment and leveling, (II) torque control, (III) space closure, and (IV) finishing. This article presents a simplified rationale for efficient sequencing of the specific archwires that are required for each stage of treatment. (Int J Orthod Implantol 2017;45:86-90)
Key words:Alias® lingual appliance, passive self-ligating, square slot, archwire sequencing