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Inside Dentistry
December 2022
Volume 18, Issue 12
Peer-Reviewed

A Full-Mouth Reconstruction With Responsible Esthetics

Elbow preparations facilitate conservative treatment for an excellent long-term prognosis

Zachary S. Sisler, DDS

When it comes to meeting patients' desires and managing risk, it can be difficult to know where to draw the line in the sand. There are many pivotal moments in clinicians' careers where a line is drawn and the ability to stand firm is a challenge. It is important for clinicians to advocate for their patients' best interests, and part of this involves keeping them from compromising long-term gains for short-term gratification.

Case Report

A 32-year-old male patient presented to the office with maxillary and mandibular molars that were so severely worn that their occlusal surfaces resembled tabletops. Given his age, he was informed that it would be in his best interest to try to mitigate the risk related to this situation in order to achieve a more favorable long-term prognosis. If the patient were to continue without treatment, he could be in a high-risk category for further breakdown, which could lead to teeth becoming non-restorable and necessitate extraction.

Upon further inspection, it was noted that the patient displayed a large anterior open bite as well as areas of exposed dentin and flattened cuspal anatomy of the posterior teeth. The right side exhibited a posterior edge-to-edge bite, whereas the left side exhibited a posterior crossbite. Despite the severe posterior wear, the patient demonstrated a low caries risk and a healthy periodontium. His temporomandibular joints and muscles of mastication were asymptomatic and displayed good range of motion in all directions.

The recommended treatment plan consisted of clear aligner therapy (Invisalign®, Align Technology) followed by the placement of posterior overlay restorations to seal the posterior wear. It was explained that by utilizing Invisalign to correct the position of the teeth and obtain anterior occlusion, the subsequent canine guidance would facilitate posterior disclusion and, in turn, protect the posterior teeth from further degradation in a predictable manner to ensure a better long-term prognosis. The patient was also esthetically driven and desired a change in the shade and appearance of his anterior teeth as well. It was explained that minimal preparation veneers utilizing an elbow preparation could be placed to accomplish that goal and that they would ultimately help provide better guidance for posterior disclusion.

The patient's next question was whether or not his goals could be accomplished without the clear aligners by getting straight to the preparations. It was explained that given the crowding of his lower anterior teeth and the severe wear exhibited by his posterior teeth, aggressive preparations would be required, which would elevate the risk and compromise the long-term prognosis. He replied, "so it is possible?" This was the line in the sand. In order to obtain an ideal functional and esthetic result, minimize the risk of the new restorations failing, and keep the veneer preparation as minimal as possible, clear aligner therapy would be needed. Once the patient recognized the importance of clear aligner therapy to minimize the risk and allow for more conservative preparations, he chose to proceed with the recommended treatment.

About the Author

Zachary S. Sisler, DDS
Accredited Member
American Academy of Cosmetic Dentistry
Private Practice
Shippensburg, Pennsylvania

Zachary S. Sisler, DDS

Pretreatment frontal smile photograph displaying an anterior open bite, right-side posterior edge-to-edge bite, and left-side posterior crossbite.

Fig. 1

Pretreatment right lateral retracted photograph displaying the crowding of the mandibular anterior teeth, which need to be moved into a better arch form prior to preparation.

Fig. 2

Pretreatment retracted close-up view of the anterior open bite with contact only on the posterior teeth and the posterior edge-to edge bite causing wear of the molars.

Fig. 3

Smile photograph acquired after the completion of clear aligner therapy, which resulted in dental expansion of the maxilla to correct the posterior edge-to-edge occlusion and crossbite.

Fig. 4

Right lateral retracted photograph with the teeth apart displaying the better alignment of the teeth after clear aligner therapy. Note the severe posterior wear.

Fig. 5

Frontal retracted view showing that orthodontic treatment closed the anterior open bite but resulted in a deep gingival embrasure to contend with during the preparation phase of the mandibular anterior teeth.

Fig. 6

Closeup view of the mandibular anterior teeth after the initial depth cuts and spatial dimensions were established for the final porcelain restorations. Due to the open gingival embrasures and the desire to practice responsible esthetics, the elbow preparation technique was utilized to maintain tooth structure and close off the proximal areas apical to the contacts.

Fig. 7

From the right lateral view of the initial preparations, it can be seen where the margins would be visible, which necessitated the need for their placement to be extended into the interproximal areas to allow for better esthetics.

Fig. 8

The final elbow preparation is completed by extending the tip of a fine-grit diamond chamfer bur into in the interproximal area apical to the proximal contact but allowing the proximal contact to remain undisturbed. This is accomplished by using the tip of the diamond bur to go under the contact and then withdrawing it, almost as if using a paintbrush, toward the incisal aspect of the tooth.

Fig. 9

In the right lateral view, the margins are now tucked away interproximally, improving the esthetics and closing off the gingival embrasure areas. The final restorations will now have a rotational path of draw.

Fig. 10

From an occlusal view, the preparation margins can be readily seen on the incisal aspects of the teeth, but then they disappear apical to the proximal contacts.

Fig. 11

Regarding the laboratory work (Juan Rego, CDT, Smile Designs by Rego), this preparation design allowed the ceramist to maintain the enamel of all of the lingual surfaces without breaking the proximal contacts of the teeth.

Fig. 12

One might anticipate that this preparation design would result in bulbous, overcontoured restorations in the interproximal area; however, from the frontal view, it can be seen that the triangular shape of the mandibular anterior teeth was maintained and that the restorations are properly contoured for esthetics and hygiene.

Fig. 13

In a right lateral view of the model, it can be seen that the ceramist masterfully created beautiful restorations with the margins completely tucked into the interproximal areas.

Fig. 14

Final posttreatment smile photograph revealing the patient with a broader arch form as a result of the clear aligner therapy utilized prior to preparation to correct the posterior crossbite.

Fig. 15

Right lateral retracted view of the final lithium disilicate restorations (IPS e.max® Lithium Disilicate, Ivoclar) with the teeth apart. The final restorations restored proper cuspal form to achieve a functionally stable occlusion.

Fig. 16

Retracted frontal view demonstrating the final occlusion, which allowed for stable stops coinciding with centric relation and smooth canine guidance.

Fig. 17

Close-up retracted view of the final mandibular anterior restorations. The use of clear aligner therapy minimized the need for preparation and the risks involved, helping the patient achieve an effortless, functionally sound smile with a favorable long-term prognosis.

Fig. 18

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