JDO Vol. 64
Writing - the key to orthodontic thinking
Dr. Chris H. Chang
Most people agree that orthodontics is a thinking game. As Warren Buffet said, “There is nothing better to get your thoughts straight than writing.” Therefore following his logic, the best way to train doctors of the young generations is by writing. In my opinion, if there were to be any shortcut to training doctors, that shortcut would be case report writing.
I started to learn and appreciate this idea 12 years ago at the 2009 AAO meeting. My Orthodontic Grandfather, Dr. Charlie Burstone, had listened to my lecture on impaction, and I could tell he liked the new approach which I had addressed in that meeting. From then on, our relationship became closer until one day I asked him a question, to which he gave a short but not sweet answer ‒
This issue has been documented….
A Two-Phase Clear Aligner Therapy for Bimaxillary Protrusion with Severe Rotation of Lower Left Second Molar
Joy Cheng, Chris H. Chang, W. Eugene Roberts
History: A 24yr-1mo-old male presented with a chief complaint (CC) of crooked teeth.
Diagnosis: The patient was diagnosed with bimaxillary protrusion combined with severe mesial-out rotation of LL7, and lingual crossbite of UL7. The Discrepancy Index (DI) was 9.
Treatment: Segmental fixed appliance combined with a ramus screw were installed to correct the severely rotated LL7 during the 6-month pre-aligner treatment. After the therapy, the rotation was successfully corrected. However, the side effect was extrusion of LL7, which resulted in poor occlusal contact that evolved into a posterior open bite during aligner treatment. Three stages of aligners (43, 18, and 15 sets respectively) were used to correct the bimaxillary protrusion, posterior open bite, and lingual crossbite of UL7.
Results: After 31 months of active treatment, this malocclusion, with a Discrepancy Index of 9 points, was treated to a Cast- Radiograph Evaluation (CRE) score of 6 points and a Pink and White esthetic score of 2 points. The patient was pleased with the treatment outcome.
Conclusions: Hybrid mechanics combining the strengths of fixed appliances and clear aligner therapy are effective in correcting bimaxillary protrusion and severe rotation of molars. (J Digital Orthod 2021;64:4-22)
Key words: Clear aligner therapy (CAT), segmental braces, clear aligner, ramus screws, bimaxillary protrusion, non-extraction, temporary skeletal anchorage devices (TSADs)
Asymmetrical Extraction Mechanism to Treat Class III Malocclusion with Anterior Crossbite and Midline Deviation
Vicky T. Huang, Bear C. Chen, Chris H. Chang, W. Eugene Roberts
Introduction: A 19yr-10mo-old male presented with a chief complaint of poor dental esthetics.
Diagnosis: Cephalometric analysis revealed a skeletal Class III relationship (SNA 85 ̊, SNB 87 ̊, ANB -2 ̊), as well as reduced facial convexity (-10 ̊) and proclined upper incisors. An intraoral assessment revealed bilateral Class III malocclusion with anterior crossbite (UR1, UL2, and UL3), and the midline was deviated 3mm to the left. Mild crowding appeared in the lower anterior dentition, and a gummy smile was apparent when the patient smiled. The Discrepancy Index (DI) was 27.
Treatment: A Damon® system appliance with passive self-ligating brackets was applied to correct the dental malocclusion after extracting four premolars (UR5, UL5, LR4, and LL5). Asymmetric extraction was carried out due to midline deviation. Posterior bite turbos and early light short Class III elastics were used to correct the anterior crossbite. Space closing and midline correction were also accomplished with elastics. The active treatment was 20 months. Gingivectomy and frenectomy were then performed afterwards to correct soft tissue contour.
Results: Improved dentofacial esthetics and occlusal function were achieved after treatment. The Cast-Radiograph Evaluation (CRE) was 10, and the Pink and White esthetic score was 3. Neither significant root resorption nor periodontal problems were noted. There were two discrepancies: non-parallel root axis of UL6 and UL7, as well as less-than-ideal interproximal contact between LL4 and LL6.
Conclusions: This case report demonstrates the use of passive self-ligating appliances to resolve skeletal and dental Class III malocclusion without the intervention of orthognathic surgery. (J Digital Orthod 2021;64:26-42)
Key words: Skeletal Class III, full-cusp Class III, anterior crossbite, midline deviation, passive self-ligating brackets, asymmetrical mechanics, gingivectomy, frenectomy
Treatment of Blocked-In Upper Lateral Incisors and Congenitally Missing Premolars with 10mm Overjet
Lily Y. Chen, Bear C. Chen, Chris H. Chang, W. Eugene Roberts
History: A 15-year-old female presented with flared upper central incisors and blocked-in upper lateral incisors with no lip contact.
Diagnosis: A skeletal Class I malocclusion (SNA 81 ̊, SNB 77 ̊, ANB 4 ̊) and an end-on molar Class III relationship with canine Class II relationship were noted. Dental analysis revealed flared upper central incisors (U1-to-NA 7mm; U1-to-SN 110 ̊), retroclined lower incisors (L1-to-MP 84 ̊) with an excessive overjet of 10mm. LR5 and LL5 were found to be congenitally missing. The facial profile was slightly convex. The Discrepancy Index (DI) was 19.
Treatment: Upper two-bicuspid extraction (UR4 and UL4) was conducted to provide space for retracting U1s and bringing the blocked- in U2s back into the arch. A passive self-ligating fixed appliance was introduced with upper anterior bite turbos and Class II elastics. Combining Class II elastics with anterior bite turbos can guide the mandible to occlude in a more protrusive position and open the bite to extrude the molars.
Results: After 25 months of treatment, a satisfactory profile and alignment was achieved. The Cast-Radiograph Evaluation (CRE) was 9, and the Pink and White esthetic score was 3. One discrepancy from an ideal occlusion was noted in the increased inclination of the lower incisors (L1-to-MP 103 ̊).
Conclusions: This case report demonstrated the treatment of blocked-in U2s in conjunction with flared U1s and bilateral congenitally missing L5s. Extracting U4s to result in one missing premolar in each quadrant is an important element of treatment planning. With proper mechanisms, anterior bite turbos and Class II elastics, a 10mm overjet can be treated to a pleasing result. (J Digital Orthod 2021;64:46-61)
Key words: Blocked-in teeth, congenitally missing teeth, excessive overjet, passive self-ligating brackets, anterior bite turbos, Class II elastics
A Biographical Portrait of Edward Hartley Angle, the First Specialist in Orthodontics, Part 2
Edward Hartley Angle (1855–1930) had essential gifts of mechanical genius and dexterity, but these traits alone could not have brought him the status of singular greatness in the history of modern orthodontics. There were many other similarly talented individuals interested in “orthodontia” during the specialty's early years. It was Angle's bold, creative drive and his confident powers of persuasion in introducing new and simplifying devices, new methods, and new nomenclature that distinguished him from his peers, then and now.
Taiwanese Lifestyle Through the Eyes of CC
Chapter 3. Rooftop Aviary
I don’t feed the birds because they need me; I feed the birds because I need them. — Kathi Hutton
Birdwatching has long been enjoyed as a recreational, as well as social activity. In the course of locating then observing different species of birds while appreciating each of their distinct sounds, birdwatchers find relaxation, refreshment, as well as excitement while immersing themselves in nature. What if such mental and spiritual satisfaction could be kept close at hand, right on your rooftop? Imagine waking up to the chirping of canaries and budgerigars that blend in with the local birdsong, golden pheasants and quail pecking on the grains by your feet, while Gouldian finches and cockatiels welcome you with their rainbow colors and bubbly hospitality…