Diastema, Virtual Gable Bend and Torque
Question:
I wanted to ask if this spacing case is predictable with invisalign the way it is showing it in such a small number of trays?
Answers by the Group:
Clearly Kelley Monday at 3:10 PM
I haven’t looked at the case yet but in general the company will spit out the least amount of aligners to save costs and be efficient.
If it looks like too few ask for 30 if it’s an adult - if it’s generalized spacing or retraction do not forget to add an attachment to first molars to prevent dumping or sinking ( unwanted / unexpected force ) I like 30-40 aligners in my initial set for adults
24 mixed
4 passive
No overcorrection or chain in first round
That gives time and you ca always change to 5 day cycles if it’s tracking ideally
I’d rather get it done predictably in 30-40 than 3 -4 sets of 16.
Chairtime and tx plans are valuable
Sabrina Bhatti Monday at 4:31 PM
In reality the crown will move easily through air and you’ll get an unfavorable inter incisal angle . Make sure you factor in more root torque. Also your overjet looks little tight and the diastema could open back up over time or end in a POB as you are also making overbite deeper. Are you planning any incisal bonding at the end?
Nour Tuesday at 3:51 PM
@Clearly Kelley @Sabrina Bhatti Thank you both for your response. (edited)
How do I determine ideal interincisal angle? and how to determine how much root torque to factor in? And yes patient does want bonding at the end. Would increasing the overjet reduce the risk of POB?
Dr. Schalk’s Answer:
Orthodontic treatment using aligners involves a careful assessment of the number of aligners needed to achieve the desired dental movements. A critical question often arises: is the current batch of aligners sufficient, or should their number be increased?
Movement of Dental Structures
Aligners facilitate the movement of crowns and roots through air, but their movement through bone is significantly more challenging. The goal is to ensure that roots are parallel at the end of treatment. When evaluating a panoramic radiograph (pan), it is essential to determine whether roots are converging, diverging, or parallel. Diverging roots, particularly in the central incisors, can complicate treatment and may indicate an incomplete fusion of the suture.
Modifications and Attachments
Adjustments to the velocity of tooth movement may be necessary, especially for the upper teeth. Historically, G4 root control attachments were used, but alternatives like 3-4mm vertical attachments are now preferred to maintain root control. For the upper teeth, 4mm vertical attachments are recommended due to changes in attachment options.
Root Movement and Restorative Considerations
Root movements often result in less change than anticipated, so planning for slightly more mesial inclination is advised. Intruding teeth and planning restorative work to address worn edges can enhance aesthetic outcomes. Additionally, a virtual gable bend between the central incisors may be beneficial.
Torque and Overjet Adjustments
Adding torque is crucial to prevent teeth from becoming too upright. Maintaining interproximal reduction (IPR) is necessary to avoid disrupting treatment plans. The ideal angulation for upper teeth is around 130 degrees, but this varies depending on the patient's class and facial structure. Class one patients are more likely to achieve this angulation compared to those in super class two or three.
In summary, successful orthodontic treatment with aligners requires careful planning and adjustments to ensure optimal outcomes. Each case must be tailored to the patient's specific dental and facial characteristics.