Prof. Ellen Ko

Facial asymmetry represents a multifaceted orthodontic and surgical challenge, requiring precise diagnosis, strategic sequencing, and coordinated multidisciplinary care. From an orthodontic standpoint, treatment aims to harmonize skeletal structures, achieve functional occlusion, and optimize facial aesthetics. Diagnostic complexities arise from compensatory dental movements, soft tissue masking, and skeletal discrepancies, which may obscure the true extent of asymmetry. Advances in 3D craniofacial imaging and surgical simulation have improved assessment; however, subtle vertical, transverse, and yaw-related deviations often persist. Pre-surgical orthodontics must prioritize skeletal decompensation—particularly in molar torque correction, arch coordination, and transverse control—while avoiding overemphasis on ideal intercuspation at the expense of basal bone alignment.

Management strategies involve targeted mechanics for vertical discrepancies (e.g., anterior and posterior cant correction through intrusion/extrusion with temporary anchorage devices [TADs] and lever arms), transverse discrepancies (e.g., transpalatal arches, rectangular archwires, rapid palatal expansion, quad helix), and dental midline control. Functional asymmetries, arch constrictions, and occlusal interferences require staged intervention, including molar uprighting, bite blocks, and cross-elastics. Segmental LeFort I osteotomies and other surgical modifications may be indicated for severe skeletal imbalances, with post-surgical accelerated tooth movement aiding in fine-tuning residual compensations.

Successful correction depends on early identification of asymmetry components, realistic goal setting, and continuous reassessment after removal of primary interferences. Integrating accurate 3D diagnostics, tailored orthodontic mechanics, and surgical precision can optimize both functional stability and facial harmony in the correction of facial asymmetry.

Deep overbite—defined as vertical overlap of incisors exceeding 5 mm or 50%—may result from dentoalveolar and/or skeletal factors such as facial growth, oral function, incisor overeruption, and hypodontia, and is most frequently associated with skeletal Class II malocclusion. Treatment aims to reduce dental wear, prevent soft tissue trauma, create space for restorations, and establish vertical occlusal support in cases with missing teeth.

Comprehensive diagnosis should evaluate facial and vertical patterns, sagittal jaw relation, dentoalveolar height in anterior and posterior regions, smile line, gingival display, anterior tooth inclination, and curve of Spee. Key contributors include exaggerated curve of Spee, maxillary incisor overeruption, and reduced gonial angle. In adolescents, differential molar extrusion combined with mandibular growth can reduce overbite, whereas adults often require anterior intrusion; severe sagittal discrepancies or facial asymmetry may indicate orthognathic surgery.

Phased treatment can involve sequential bonding where space is limited, beginning with maxillary leveling and partial anterior intrusion, aided by posterior bite turbos or maxillary removable plates. Lower arch expansion and leveling the curve of Spee can open the bite and correct Brodie bite in severe cases. Once overjet is reduced, anterior bite turbos may facilitate molar extrusion. Adequate maxillary anterior palatal root torque supports optimal interincisal angulation and stability. Temporary anchorage devices (TADs) assist with sagittal correction and anterior intrusion.

Post-treatment stability is improved by combining a lower fixed retainer with a maxillary removable anterior bite plane. Long-term outcomes are more stable when overbite correction is complete and interincisal angulation is appropriate; relapse occurs in about 10% of cases, particularly with partial correction.

Course Abstract:

This intensive hands-on course provides orthodontists and trainees with a comprehensive foundation in  he clinical application, anatomical considerations, and insertion techniques of temporary anchorage devices (TADs). Emphasis will be placed on integrating anatomical safety zones, biomechanical principles, and evidence-based insertion strategies to optimize outcomes and prevent complications.

Participants will learn:

• Clinical Indications and Applications: From absolute anchorage in en masse retraction to molar intrusion, midline correction, and non-compliant patient management, TADs offer versatile anchorage solutions across a range of orthodontic challenges. 

• Site Selection and Anatomical Landmarks: Detailed analysis of interradicular and extra-alveolar sites in both maxilla and mandible, guided by CBCT data and bone thickness mapping from literatures and clinical exploration.

• TAD Design Selection: Criteria for choosing screw length and diameter based on location-specific bone quality, soft tissue characteristics, and clinical goals. Stainless steel versus titanium options will also be discussed.

• Insertion Techniques and Angulations: Practical training in safe and effective TAD placement, including insertion angle optimization, soft-tissue handling, and transgingival protocols for enhanced stability.

• Complication Management and Prevention: Identification and prevention of root damage, soft tissue inflammation, peri-implantitis, screw fracture, and sinus or nerve injury. Emphasis will be placed on risk assessment, torque control, and post-insertion monitoring.

By combining didactic instruction, anatomical reviews, and hands-on exercises with synthetic and animal models, participants will leave with the skills and confidence necessary to apply TADs safely and effectively in clinical practice.