Congenitally missing teeth are not an unusual occurrence. What makes this case study unique is the combination of restorative challenges offered. The patient presented with the permanent upper right cuspid and lower anterior right and left central incisors congenitally missing, and with an underdeveloped upper right lateral incisor. Distinctive existing occlusion and tooth alignment difficulties precluded a simple approach of merely extracting the residual primary teeth and replacing the missing teeth prosthetically. Using orthodontics to create ideal interocclusal and interarch space was critical in preparing this case for prosthetic restoration.

OFTEN, PATIENTS WHO PRESENT with difficult prosthetic and cosmetic concerns can benefit from a combination of different dental disciplines. Instead of trying to solve cases with a single method of treatment and simply making“the best of it,”dentists today can use several different treatment modalities to help achieve maximum success.

This case demonstrates how an adult patient who disliked his three over-retained primary teeth required pre-prosthetic orthodontic intervention prior to restoration with implant, prosthetic and cosmetic dentistry.

  

A healthy 33-year-old male presented with several dental concerns. He had three over-retained primary teeth and was congenitally missing their permanent successors. The diminutive appearance of the primary upper right canine and primary lower anterior right and left central incisors had always bothered him (Figure 1). Furthermore, he was unhappy with the esthetic appearance of an underdeveloped upper right lateral incisor, “long” upper central

incisors, and a space between the lower right canine and lateral incisor (Figure 2).

Examination showed such a deep overbite that the incisal edges of the upper centrals were causing traumatic inflammation to the lower labial gingiva and almost total obscurity of the lower primary central incisors. The lower right canine was distally inclined and had extruded past the occlusal plane into the space of the opposing undersized upper right primary canine (Figure 3).

Because there was minimal interocclusal space, the current position of the upper permanent central incisors left only enough interarch clearance for the existing primary central lower incisors; there was inadequate space to accommodate “adult-sized” central incisors. The tilt of the lower right canine also prevented replacement of the upper primary right canine with an adult-sized canine tooth (Figure 3).

In order to make this case restorable, orthodontic treatment was imperative. The objectives were as follows:

• To reduce the amount of overbite and attain a more favorable overjet by intruding the upper central incisors and reducing their degree of angulation and proclining them.
• To improve the position of the upper right lateral incisor by moving it closer to the upper right central incisor but to avoid tipping it. This would increase spacing to accommodate a more ideal-sized canine implant and restoration.
• To upright the distally inclined lower right cuspid so that it would no longer intrude into the space of the missing upper cuspid and to allow placement of an upper right canine implant and crown. Bone grafting would be necessary to provide sufficient bone for successful placement and integration of an implant in the lower anterior region.

Treatment objectives were realized through the use of a series of 26 Invisalign1 orthodontic aligners over 12 months. At the first aligner visit, the retained primary teeth were removed and resin pontics were placed into the corresponding spaces of the aligners. The pontics were replaced with each new aligner and provided a satisfactory provisional for the edentulous spaces throughout treatment. The aligners were worn 24 hours a day and were changed every two weeks. They were removed only for eating and for oral hygiene.

The overbite was reduced; the overjet improved; and judicious use of interproximal reduction (IPR) improved the alignment of the upper incisors (Figure 5). Careful creation of .3 mm. of interproximal space between teeth #7 and #8 and between teeth #8 and #9 allowed for stable contacts without changing the curvature or anatomy of the teeth. This was accomplished by using Qwik-Strips,2 which allow for minimal tooth reduction precisely at the contact points without damaging the facial or incisal aspect of a tooth. “Ledging,” a common occurrence when performing IPR, is also avoided when using this method.

The lower right canine was successfully tipped mesially to close the canine-lateral space and provide sufficient room for the opposing upper right canine implant and crown (Figure 6).

Between weeks 50 and 52, the patient whitened his teeth, using the take-home Nite-White3 bleaching system. He was able to use his aligners as his whitening trays. The appearance of the underdeveloped upper right lateral incisor was improved with resin bonding.

A synthetic bone substitute was placed in the lower anterior region. A single 3.75 x-13 MIS4 implant was placed in the lower central incisor area (Figure 4) and a 3.75-x 11.5 MIS implant was placed in the upper right canine edentulous area. A porcelainfused-to-gold crown was shaped to resemble two, individual central incisors and was used to restore the single lower central implant (Figure 8). A porcelain-fused-togold crown was used to restore the upper canine implant (Figure 9).

After treatment, Invisalign retainers were worn at night to hold all teeth in their new position.

This case illustrates a successful, multi-disciplinary approach to a very complex restorative challenge. By using orthodontics, oral surgery, prosthetics and cosmetic dentistry, a highly satisfactory result was achieved.

Comprehensive evaluation and thorough treatment planning were crucial. If the primary teeth were simply removed and replaced with implants or removable prostheses, the case would have been doomed to failure because the pre-treatment occlusion did not allow for the proper clearance needed to restore this case. Using orthodontics first to create ideal interocclusal and interarch space was critical in preparing this case for prosthetic restoration. To that end, the Invisalign appliance served as an important and patient acceptable adjunctive appliance.

The Invisalign appliance helped position the teeth and served as a provisional restoration, and aided in cosmetic whitening and retention once orthodontics was completed.

Queries about this article can be sent to Dr. David Galler at drgaller@hotmail.com

• Align Technology. California, USA.
• Axis Dental. Texas, USA.
• Discus Dental. California, USA.
• MIS Implants Technologies Ltd. Shlomi, Israel.