The Clear Plan by Dr. Jeff Alba

The Clear Plan 

Integrating CBCT data into clear aligner treatment planning


by Dr. Jeff Alba


Think back to the early days of your career as an orthodontist. Who had the most significant impact on who you are as a person and orthodontist today? For me, the answer is easy—my dad, Dr. Fred Alba. He has taught me all I know about life, orthodontics and exterior illumination (for all you National Lampoon’s Christmas Vacation fans).

One of the most important lessons I have learned is not to accept the status quo. Instead, always be inquisitive, challenge the norm and innovate.

Along these lines, my father also taught me that the adoption and implementation of new technology can dramatically enhance clinical efficiencies and outcomes. One of the ways our practice has done this is by incorporating intraoral scanning and cone-beam computed tomography (CBCT) into our daily workflow.

Added knowledge for better decisions

In 2010, we began using the Insignia custom bracket system, and in 2017, we were early adopters of the TruRoot data integration for Insignia. The TruRoot process utilizes CBCT and an intraoral scan to populate an accurate representation of the patient’s anatomy in the approver software. Once we integrated TruRoot into our workflow, it didn’t take long for us to see a tremendous decrease in digital design time and an increase in clinical efficiency.

In 2019, Ormco launched its Spark clear aligner system to the North American market, so we jumped on the opportunity to try it and recently completed our first month of the Spark TruRoot clinical trial. It has been a game changer for our practice. With the CBCT-integrated roots, the detail of the anatomy of the roots is incredible. You now can adjust tip, torque and rotation of teeth to account for anomalous root morphology like dilacerations. Not only do we spend less time on each case design, but we also find treatment is more efficient with fewer refinements on average. This is a win-win for our patients and our practice.

Although we believe that root visualization has had the most considerable impact on efficiency, we use this same CBCT data to visualize the current and planned positions of teeth within the alveolar bone and face. This facilitates treatment results that are both periodontally favorable and maximally aesthetic.

CBCT integration is also beneficial when considering whether extractions are necessary. For example, visualizing the planned root position in the alveolar bone can confirm if the amount of arch development required is periodontally acceptable. Similarly, this information is invaluable when contemplating the treatment of crossbites via dental expansion or planning complex interdisciplinary cases involving the placement of implants.


CASE STUDY

Diagnosis

A 27-year-old patient sought orthodontic treatment to correct his anterior open bite (AOB) and spacing. He presented with a dolichofacial convex Class II skeletal pattern. The maxillary occlusal plane was tipped inferiorly in the posterior region, resulting in a downward and backward rotation of the mandible. A functional mandibular shift of 1 mm to the right was noted secondary to a slightly constricted maxilla and crossbite of the UR3 (Figs. 1–3).

The Clear Plan
Fig. 1: Initial photo composite, Feb. 5, 2021.
The Clear Plan
Fig. 2: Initial pano cut from CBCT.
The Clear Plan
Fig. 3: Initial ceph cut from CBCT.


Additional findings:
  • Class III tendency of the left molar and canine; Class II relationship of the right canines.
  • 1 mm overjet; –3 mm overbite.
  • 90% incisal display on smiling.
  • Reverse smile arc.
  • Proclined and slightly intruded maxillary incisors; proclined and intruded mandibular incisors.
  • Maxillary midline 1.5 mm to the left of facial and mandibular midline 2.5 mm right of facial.
  • Mild maxillary spacing and moderate mandibular spacing.
  • Bolton discrepancy with 2.4 mm mandibular excess.
  • Thin gingival biotype.
  • TMJ: WNL.
  • Tongue thrust habit.

Treatment plan and digital setup
Because of the anterior open bite and the patient’s desire for a comfortable and aesthetic treatment option, an estimated 18-month treatment with Spark Clear Aligners was planned. Our treatment goals were to close the AOB, broaden the maxillary arch to eliminate the UR3 crossbite and functional shift, obtain a Class I occlusion, close spacing, obtain coincident midlines and improve the smile arc.

Using an iCat FLX, an arches/TMJ QuickScan+ CBCT was taken, with an effective dose of 9 microsieverts and dose area product of 79.6 milligrays per square centimeter.1 The data was uploaded into Spark Approver software and used to coordinate maxillary and mandibular midlines with the face (Figs. 4a and 4b), plan the desired final incisor vertical and A-P positions (Figs. 5a and 5b), and assess planned tooth positions within the alveolar bone.

The Clear Plan
Fig. 4a: Initial CBCT overlay to assess midlines.
The Clear Plan
Fig. 4b: CBCT overlay of planned dental midlines.
The Clear Plan
Fig. 5a: CBCT overlay of initial Spark Approver model.
The Clear Plan
Fig. 5b: CBCT overlay of planned Spark Approver model.


Uprighting and relative extrusion of the anterior teeth and intrusion of the posterior teeth along with mandibular autorotation was planned to close the AOB. Some 3-mm gingivally beveled attachments were placed on the U2–2 to aid in the uprighting and extrusion of these teeth. Spark’s posterior bite turbos (PBTs) were added to upper and lower 6s and 7s to increase the predictability of maxillary and mandibular molar intrusion (Fig. 6).

The Clear Plan
Fig. 6: Initial Spark Approver attachment and elastic design.


The UR3 crossbite with functional shift masked the actual A-P dental discrepancy, so we set up Class II and Class III elastics on both sides to allow for flexibility of elastic vectors during treatment. In addition, we added a palatal button to the UR3 and a buccal button on the LR4 to assist in crossbite resolution. A 0.3 mm interproximal reduction (IPR) from mesial LL3 to mesial LR3 was planned to occur at aligner #20 once the L3–3 spacing was consolidated. The initial aligner set consisted of 29 active aligners, five passive aligners and three overcorrection aligners.

Treatment
All attachments and buttons were bonded at the initial visit. The patient was given all aligners in this series and began full-time wear of a 3/16-inch, 3.5-ounce crossbite elastic from UR3 palatal to LR4 buccal and a 5/16-inch, 3.5-ounce Class III elastic from LL3 to UL6. He returned 10 weeks later for an elastic and aligner check. All the teeth were tracking well at this visit, and we continued with the same elastics. The patient once again returned in 10 weeks for IPR. We continued with the same elastics.

The patient missed one visit, and his scan for refinement aligners was delayed by four weeks. When he presented for a refinement scan, the crossbite of the UR3 had been resolved, the functional was shift-eliminated, the spacing had primarily been closed, positive overbite was obtained, the smile arc improved, and the midlines were coincident with the facial midline. At this point, his incisors were slightly detorqued, and his occlusion was a weak Class I at the canines and needed to be socked in (Fig. 7).

The Clear Plan
Fig. 7: Refinement photo composite, Nov. 10, 2021.


In the refinement setup, torque was added U/L 2–2, the palatal button on the UR3 was moved to the labial, and the occlusion socked in. The patient returned five weeks from the time of the refinement scan, and 11 refinement aligners were delivered. Also, at this time, the patient began full-time wear of a 3/16-inch, 3.5-ounce short Class II elastic from UR3 labial to LR4 buccal and a 5/16-inch, 3.5-ounce Class II elastic from UL3 to LL6.

When he returned 11 weeks later, all attachments were removed and final records were taken (Figs. 8–10). A 0.4-inch Essix retainer was fabricated for the maxillary arch, and a fixed lingual retainer bonded to the L3s only was placed along with a 0.4-inch Essix overlay for the mandibular arch.

The Clear Plan
Fig. 8: Posttreatment photo composite.
The Clear Plan
Fig. 9: Posttreatment pano cut from CBCT.
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Fig .10: Posttreatment ceph cut from CBCT.


Treatment analysis and conclusion

Treatment was completed in 11 months and two weeks with six total visits, demonstrating that the integration of CBCT data and proper planning can enhance clinical efficiencies.

We know what we planned, but what really happened? Within TxStudio, we can superimpose pre- and posttreatment CBCT volumes to evaluate our treatment outcome. The mandible was superimposed on its inferior border and symphysis. The superimposition on the mandible shows uprighting, slight retraction and relative extrusion of the mandibular incisors to a position centered within the alveolus (Fig. 11a). In addition, we can see in the coronal view of the mandibular superimposition that the final position of the mandibular molars have intruded, compared to pretreatment (Fig. 11b). The maxilla was superimposed on the inferior border of the malar processes (Fig. 12). The superimposition on the maxilla shows some uprighting and relative extrusion of the maxillary incisors, but reveals that a large portion of the bite closure occurred as a result of autorotation of the mandible secondary to maxillary molar intrusion.

The Clear Plan
Fig. 11a: Superimposition on the mandible
(sagittal).
The Clear Plan
Fig. 11b: Superimposition on the mandible
(coronal).
The Clear Plan
Fig. 12: Superimposition on the maxilla
(sagittal).


Conclusion

As I write this article, it is Masters week and Tiger Woods is playing in his first competitive tournament since his auto accident. If you were to give me Woods’ golf clubs, I have about as good of a chance of winning the Masters as I do seeing 100% elastic compliance in my practice.

Similarly, the integration of CBCT data into clear aligner treatment planning is an incredible tool, but it is a tool; it cannot replace the expertise and clinical judgment of a trained orthodontist. For example, this integration will show that the incisors can be placed in an aesthetic and periodontally stable position within the face and alveolar bone. However, it is imperative to remember that proper clear aligner mechanics and accurately prescribed overcorrections must still be planned to move the teeth to that desired position.

Spark was one of the first clear aligner systems to embrace the integration of CBCT data and roots years ago, but other systems also are beginning to realize its importance. I encourage you to follow my dad’s advice, question the status quo and try a few clear aligner cases with CBCT integration. I hope it has as big of an impact on your efficiency as it did ours.


Reference
1. Ludlow, John B., and Walker, Cameron. “Assessment of Phantom Dosimetry and Image Quality of I-Cat FLX Cone-Beam Computed Tomography.” American Journal of Orthodontics and Dentofacial Orthopedics, Vol. 144, No. 6, 2013, pp. 802–817. https://doi.org/10.1016/j.ajodo.2013.07.013.

Author Bio
Dr. Jeff Alba Dr. Jeff Alba received his certificate in orthodontics and dentofacial orthopedics from the Temple University Kornberg School of Dentistry. After residency, he returned to his hometown of Mechanicsburg, Pennsylvania, where he joined his father in a one-location private practice that blends fundamental orthodontic principles with digital treatment planning to provide customized state-of-the-art orthodontics for all ages.

Alba, a paid consultant for Ormco, has a passion for innovation and technology and is involved with many of the clinical trials for the Spark Clear Aligner system.
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