Dr. Chris H. Chang
Learn from a True Master
In 2017, I was blessed to meet a true aligner master, Dr. Kenji Ojima. After listening to his one-day lecture, I was completely hooked. Two days later, we met again in Rome, Italy. We held lectures together at the Italian Society of Orthodontics International Congress and consequently became close friends. I have had the privilege to learn from his aligner experience firsthand, and I decided that our office, Beethoven Orthodontic Center, would from that point on follow his methods.
Five years later, the Taiwan Association of Orthodontists (TAO) 2022 Annual Meeting arranged Dr. Kenji and yours truly in the same section to discuss how to treat difficult cases with aligners. After my lecture, a female professor came to me and made an interesting comment, “After listening to your lecture, I felt that I was like a frog living in a shallow well.” I was so surprised by her comment, as we had sat together when I first heard Dr. Kenji’s methodology…
Asymmetric Skeletal Class III Malocclusion with Missing Molars and Deep Anterior Crossbite
Sophia P.-W. Shu, Kristine Chang, Chris H. Chang, W. Eugene Roberts
History: A 25-year-old male presented with chief complaints (CC) of anterior crossbite and protruded lower lip.
Diagnosis: The patient was diagnosed with a Class III malocclusion, associated with anterior crossbite (overjet = -3mm), deep bite (overbite = 8mm), asymmetric missing teeth (UR6, UL5, LL7), and a concave profile. The ABO Discrepancy Index (DI) was 43.
Treatment: This severe malocclusion was corrected with extraction of mandibular first premolars and a passive self-ligating (PSL) fixed appliance. Class III early light short elastics (ELSE) and bite turbos were used to resolve the anterior crossbite.
Results: Following 30 months of active treatment, the skeletal Class III malocclusion was successfully aligned, and the anterior corssbite was corrected by retracting the lower anterior segment. Both the concave profile and the protrusive lower lip were improved. This malocclusion, with a Discrepancy Index of 43 points, was treated to a Cast-Radiograph Evaluation (CRE) of 8 and a Pink and White (P&W) dental esthetic score of 5 points. The patient was pleased with the treatment outcome.
Conclusions: A severe skeletal malocclusion was corrected in 30 months with a full-fixed PSL appliance, bite turbos, early light short Class III elastics, and space closure mechanics. (J Digital Orthod 2023;69:4-22)
Key words: Class III anterior crossbite malocclusion, passive self-ligating brackets, asymmetrical dentition
Premolar Substitution of Missing Canine with Crowding and Midline Deviation
Maurice Huang, Joshua S. Lin, Chris H. Chang, W. Eugene Roberts
History: A 29-year-old female presented with chief complaints of crooked teeth and crowding.
Diagnosis: Lower facial height, convexity, and lip protrusion were within normal limits. Bimaxillary retrusion (SNA, 76˚; SNB, 73˚; ANB, 2.5˚) and a high mandibular angle (SN-MP, 42.7˚) were noted. Both upper and lower incisors were within normal limits (U1 to SN, 102˚; U1 to NA, 5.5mm; L1 to MP, 95.1˚; L1 to NB, 4mm). In the right buccal segment, the molars were Class I, but the upper right canine and the upper left first molar were missing. There was >10mm of crowding in the lower arch, and the upper dental midline was shifted 4mm to the right. The Discrepancy Index was 23.
Treatment: Following extraction of two mandibular first premolars, all teeth were bonded with a Damon Q® passive self-ligating bracket system. An infrazygomatic crest bone screw was inserted buccal to the upper left second molar. A power chain applied to the upper arch corrected the midline deviation and closed the upper left first molar extraction space. In addition, premolar substitution for the missing upper right canine was performed. Both arches were detailed and finished.
Outcome: After 29 months of active treatment, all teeth were aligned, and all extraction spaces were closed. The upper right first premolar was substituted for the missing upper right canine. The midline discrepancy was corrected to 1mm after the active treatment. The final alignment and dental esthetics were satisfactory as evidenced by an ABO Cast-Radiograph Evaluation score of 12, and the IBOI Pink & White Esthetic Score of 4. Both the patient and the clinician were satisfied with the final outcome.
Conclusions: Missing canines usually have a history of ectopic eruption, impaction, or trauma. Premolar substitution is an attractive treatment option, but may result in substantial midline deviation. Orthodontic bone screws play an important role in correcting midline deviation with asymmetric mechanics. (J Digital Orthod 2023;69:30-45)
Key words: Midline deviation, premolar substitution, IZC bone screw, asymmetric mechanics, temporary skeletal anchorage devices (TSADs), passive self-ligating brackets
Finding the Happy Medium: Buccal Shelf Screws as a Minimally Invasive Approach to Treat Severe Skeletal Class III Malocclusions
Kristine Chang, Jenny Chang, Laurel Shern, Chris H. Chang, W. Eugene Roberts
History: An 18-year-old male presented with chief complaints of an underbite and difficulty chewing.
Diagnosis: The skeletal Class III malocclusion (SNA, 83°; SNB, 88.5°; ANB, -5.5°) was associated with proclined upper incisors (U1 to SN, 113.5°) and retroclined lower incisors (L1 to MP, 81.5°). The Discrepancy Index (DI) was 65.
Treatment: Early light short Class III elastics were used to correct the malocclusion. Low torque brackets were selected for the upper incisors, and high torque brackets for the lower incisors to provide better root torque control. Two miniscrews were inserted in the buccal shelves (BS) to retract the lower arch.
Outcome: After 29 months of active treatment, this severe, challenging skeletal Class III was corrected to an acceptable result. The occlusion was stable and the patient was pleased with his facial profile. The Cast-Radiograph Evaluation (CRE) was 29, and the dental esthetic (Pink & White) score was 3.
Conclusions: It is good to bear in mind that “nothing is perfect; find the happy medium”. It is important for the clinician to understand when to stop the treatment and to reach an outcome that is acceptable to both the clinician and the patient. (J Digital Orthod 2023;69:54-70)
Key words: Skeletal Class III, buccal shelf miniscrews, passive self-ligating brackets, Class III intermaxillary elastics, anterior root torque spring
Taiwanese Lifestyle Through the Eyes of CC
Chapter 8. Maximizing spaces and resources - Front yard aviary with water feature
“I love how you respect the tree, not just cutting it off like most people do.” - Mr. Filippo Impieri (SVP, Emerging Markets, Envista)
Let’s begin this chapter with a story of another of the Changs’ neighbors, on his daily stroll. Upon passing the Changs’ garage, something caught his attention and forced him to stop his steps to ponder thereupon. “The design of this garage ceiling is most curious!” He must have thought to himself. Having retired from a fairly large construction company, he is familiar with all sorts of popular front yard/garage designs that suit the lifestyles and likings of Taiwanese household, but never has he seen anything like this. A bright “chirp!” Interrupted his train of thought as he realized the double-layered ceiling he was looking at, built with bulletproof glass on the top layer and mesh on the sides and the bottom layer, was actually an aviary - or to be more exact, part of an aviary.
As the Chang family’s love for birds grows, so does the number of feathered residents in their household. Therefore, after they started planning the garage renovation, the idea of a front yard aviary followed. And this is when everything gets doubly exciting and inspiring…