Dr. Chris H. Chang
Orthodontic Advanced Education after COVID-19
COVID-19 has impacted many industries in the world, including ours, and this has led me to reconsider the methods for orthodontic education. During this period, even if you had gone to the United States to learn orthodontics, most courses would have been taught primarily with online videos. Therefore, is there actually any real educational difference between studying online lessons in the United States and doing exactly the same thing in Taiwan? If there is no discernable difference between the two, then I personally would prefer being trained in the comfort of my home in Taiwan. Why spend so much time and money going to the United States to receive the same education?…
Clear Aligners and TSADs for the Treatment of a Skeletal Class II Malocclusion with Severe Overjet and Deep Overbite
Nawal J. Al Mutawa, Joshua S. Lin, Chris H. Chang, W. Eugene Roberts
History: A 42-year-old male presented for orthodontic consultation with a severe Class II malocclusion, overjet of 14mm, and a deep bite with flared anterior teeth. His chief complaints were poor esthetics and masticatory function.
Diagnosis and Etiology: Flared, gapped, and over-erupted upper anterior teeth resulted in a severe overjet of 14mm. Lower anterior teeth were also over-erupted, impinging on the upper anterior palate and resulting in an overbite of 8mm. Gingival recession was found along the palatal surfaces of the upper incisors. No significant mobility of anterior teeth was observed. Long, narrow upper dental arch with mesially rotated UR5 was noted, as well as Class II molar relationship on the left side, Class II canine relationships on both sides, and a skeletal Class ll malocclusion (ANB, 6̊). The probable etiology for the increased overjet included external factors such as thumb-sucking in childhood and existing habits like mouth-breathing, which led to over- eruption of upper anterior teeth (internal factors). Loss of proper overjet led to overeruption of lower anterior teeth, which developed into deep bite.
Treatment: A non-surgical, non-extraction orthodontic treatment protocol with aligners and temporary skeletal anchorage devices (TSADs) was generated. Intraoral scanning for digital impressions, full records, and prescription form were submitted for Invisalign comprehensive clear aligners. A set of 34 aligners for the first phase was designed. The attachments were bonded on the second visit, TSADs were inserted in the infrazygomatic crest (IZC) bilaterally, and early Class II elastics were used. On completion of the first set of aligners, a significant improvement on overjet and overbite, de-rotation of UR5, and Class I molar and canine relationships on both sides were achieved.
Outcomes: Treatment goals were achieved after 18 months of treatment with clear aligners. (J Digital Orthod 2022;68:4-18)
Key words: Skeletal Class ll malocclusion, Class ll molar relationship, curve of Spee, vertical dimension of occlusion (VDO), TSADs, Class ll elastics, overjet, overbite
Treatment of a Class I Bimaxillary Protrusion, Crowding, and Black Triangles
Yi-Hsuan Lin, Joshua S. Lin, Chris H. Chang, W. Eugene Roberts
Introduction: A 24-year-old female presented with chief complaints of flared upper central incisors and blocked-in right upper lateral incisors with protrusive lips.
Diagnosis: The cephalometric analysis revealed a skeletal Class I relationship (SNA, 89 ̊; SNB, 83 ̊; ANB, 6 ̊) and proclined upper and lower incisors. An intraoral assessment revealed partial crossbite of the upper right lateral incisor as well as blocked-out eruption of the upper left second premolar, and the midline was deviated 1mm to the right. There was crowding in both the upper and lower anterior dentitions. The Discrepancy Index (DI) was 38.
Treatment: A Damon® system appliance with passive self-ligating brackets was applied to correct the dental malocclusion after extracting four premolars (UR4, UL5, LR4, and LL4). Asymmetric extraction was carried out due to the upper left second premolar being intruded with a curved root. Space closure and midline correction were accomplished with elastics. The active treatment time was 31 months.
Results: Improved dentofacial esthetics and occlusal function were achieved after treatment. The Cast-Radiograph Evaluation (CRE) score was 24, and the Pink and White esthetic score was 3. Neither significant root resorption nor periodontal problems were noted.
Conclusions: This case report demonstrates the use of passive self-ligating appliances to resolve severe anteriorly proclined teeth without using an orthodontic bone screw. (J Digital Orthod 2022;68:26-41)
Key words: Skeletal Class I, proclined anterior teeth, anterior crossbite, midline deviation, passive self-ligating brackets, asymmetrical mechanics
Impacted Maxillary Canines: Auto-Eruption in Moderately Crowded Mixed Dentition
Chi-Hsien Lin, Joshua S. Lin, Chris H. Chang, W. Eugene Roberts
Introduction: A 10y-9m-old female presented with chief complaints of bilateral maxillary impacted canines in the late mixed dentition stage. The premolars had begun to erupt.
Diagnosis: There was moderate anterior crowding in the maxillary arch, and the maxillary canines were impacted. Crossbite of both maxillary lateral incisors was noted. The total Discrepancy Index (DI) for this malocclusion was 57, including an Impaction Specific Assessment System (iSAS) score of 19 points.
Treatment: The anterior crossbite was corrected using a passive self-ligating appliance, supplemented with a bite turbo on the lower left lateral incisor. Open coil springs were placed to gain spaces for eruption of the impacted canines.
Results: After 25 months of active treatment, the Cast-Radiograph Evaluation (CRE) score was 13. Superimposition of the cephalometric tracings showed that the SNA, SNB, and ANB angles increased 8°, 3°, and 5° respectively, which resulted in a more harmonious facial pattern. Besides, U1-SN and L1-MP both increased from retroclined to more ideal angles. The 1-year follow-up photographs revealed that both facial esthetics and occlusion were stable.
Conclusions: In mixed dentition, clinical signs of delayed or ectopic eruption should be confirmed by panoramic and cephalometric films first. For upper canine impactions to erupt spontaneously, angle of inclination and initial height of the impaction are critical. Preserving Leeway space can help relieve crowding. Lastly, different bracket selections depending on factors such as displaced position of impacted canines, non-/extraction of the adjacent teeth, and initial inclination of anterior segment are efficient for achieving desirable outcomes. (J Digital Orthod 2022;68:46-63)
Key words: Impacted maxillary canine, mixed dentition, Leeway space, open coil spring
Taiwanese Lifestyle Through the Eyes of CC
Chapter 7. Wild Garden for Chickens
“Love your life. Perfect your life
Beautify all things in your life
Seek to make your life long and its purpose in the service of your people.”
— Chief Tecumseh (1768-1813)
As life expectancy increases, how we live our later years becomes an important issue that we all need to give some thoughts to, if we hope to pursue a life that is meaningful and of quality. One of Dr. Chris Chang’s neighbor, Dr. Sheng, who is in his mid-90’s, takes a stroll every morning in the neighborhood, and stops at the pond near Dr. Chris’s house to feed the fish. This scene inspired Dr. Chris to examine his daily routine and habits as he realized that good habits give us guidelines for life. Having awareness of our routine and habits, both good and bad, helps us to identify the things that we want or need to change. Improvements, then, are no longer abstract concepts, but become feasible plans and procedures…