Jerry Gardner, DDS

Disclosures

January 14, 2011

Clinical Presentation: A Middle Aged Woman With Decreased Vertical Dimension

A 74-year-old postmenopausal black woman, a patient for 30 years, with a poorly fitting lower partial denture, presented with complaints of severe wear of her remaining lower teeth (Figure 1). Her periodontal condition was stable; teeth numbers 3 and 14 had been previously extracted 40 years earlier, with resulting maxillary ridge osseous loss. In addition to a desire for a mandibular fixed bridge to replace the partial denture, the patient reported a need to be fiscally conservative for treatment. This ruled out implant options.

Figure 1. Preoperative view, open mouth position.

Medical History and Dental Examination

History. The patient's medical history was unremarkable, with no history of phosphonate use. She is a nonsmoker, with no reported joint or osseous pain.

Dental examination. Approximately 5 years before the examination, a maxillary anterior bridge was placed, anchored by teeth numbers 6-11. Severe wear facets were present on mandibular teeth numbers 24-26, with supereruption of tooth number 27. A porcelain-bonded-to-metal (PBM) bridge, which showed evidence of porcelain fracturing and poor marginal adaptation, splinted teeth numbers 22 and 23. Both teeth had been endodontically treated, with clinical abutments foreshortened to less than 3 mm, resulting in significant loss of vertical dimension.

Radiographs. A full panoramic radiograph was taken. No periodontal disease was evident.

Diagnosis

Vertical dimension occlusion (VDO) was reduced by at least 1.5 mm, evidenced by the following:

  • Severe wear facets on opposing posterior teeth numbers 1 and 32;

  • Severe wear on the incisal edge of the mandibular anterior teeth; and

  • Supereruption of maxillary teeth numbers 2, 4, 5, 12, 15, and 16, into opposing pre-existing mandibular edentulous areas.

Concurrently, severe wear of the acrylic teeth on the 10-year-old mandibular acrylic partial resulted in extreme changes in the patient's curve of Spee. This is the natural, anatomic curvature of the occlusal alignment of the teeth.[1] Beginning on the tip of the lower canine, the curve follows the buccal cusps of the natural premolars and molars, and continues to the anterior border of the mandibular ramus, creating a natural smile line.

Treatment Plan

Opening up the patient's vertical dimension and correcting the curve of Spee to create a natural smile were the keys to achieving the treatment goals. The goal for treatment was to provide the patient with maximum aesthetics and function, while assuring reasonable cost.

Detailed treatment planning. Beginning with initial impressions and casts, this case required careful recording and assessment of patient occlusion, with repeated measurement of the current and desired occlusion to ensure accuracy. Initial occlusion was checked with plaster casts and final adjustments were made on a working model, poured from hard crystalline type 3 gypsum or yellow dental stone on an articulator (Artist Articulator; Amann Girrbach Articulator, Spring Hill, Florida) to determine the best way to regain VDO.

Placing marks on the patient's nose and chin, a relaxed position for VDO was obtained. Because there were no vertical stops anterior, from the contacts of the opposing maxillary bridge to the lower anterior teeth, and posterior, from the occlusal stop for tooth number 1 and opposing tooth number 32, comparisons between the distance from the registered soft tissue marks were made against measurements of the occluded mounted casts on the articulator. Therefore, the goal to reestablish proper VDO would be achieved by adjusting for differences between the 2 measurements. Recordings of occlusal adjustments on specific teeth on the stone casts were made to facilitate maximum interdigitation and functionality.

Based on this initial assessment and mounting, teeth numbers 22-27 and number 1 with opposing number 32 were adjusted with provisional temporary crowns to open up the VDO, allowing space to accommodate the new partial and to avoid further wear of the anterior teeth. Porcelain-fused-to-metal (PFM) crowns were to be placed on the lower anterior teeth numbers 22-27 and PBMs on teeth numbers 1 and 32. It was important to add 1.5 mm to the worn occlusal surface of tooth number 32. This accomplished the greatest VDO increases, and facilitated the vertical length necessary to restore the patient's lower arch. Following successful adjustment on the mounting, the VDO was reestablished. The next step was to replicate this in the patient's mouth.

Treatment Stages

Proper staging, diagnosis, and evaluation were critical to success for this case.

Occlusal adjustment. After performing enameloplasty on the maxillary teeth to compensate for supereruption, the occlusal plane of the lower existing partial was adjusted to create full intercuspation with the new curve of Spee. This permitted the necessary space for creating the new lower partial.

Establish new occlusal plane. New provisional acrylic temporary restorations were fabricated for teeth numbers 22-27 to adjust to the new VDO. New provisionals were placed on numbers 1 and 32 to stabilize the new VDO. After provisional occlusion for several weeks with no symptoms, the patient was stable enough to begin final restorations in the opened position. The treatment plan was replicated, splinting teeth numbers 22-27, placing appropriate cingulum rests and clasps to support and distribute biting forces of the partial for teeth numbers 26 and 27. Teeth numbers 24 and 25 were prepared as single unit PFMS. Tooth number 32 was prepared for full coverage, with a mesial rest seat and curvature to allow room for placement of a clasp that would provide proper support and retention of the partial during movement.

Coordinate laboratory fabrication. Full coverage PBM on tooth number 1 was designed as a vertical stop to ensure proper VDO and maintenance of VDO. Coordination with 2 different types of dental laboratories was necessary. The plan for the partial design was coordinated with the denture laboratory, who fabricated the partial denture. The modified working model in yellow stone with the fabricated provisional restorations in place was also sent. Following submission and approval of the initial partial denture design from the denture laboratory, this new working model was sent to a second (crown and bridge) laboratory to fabricate the PFM and PBM crowns, with the new upper and lower impressions for fabrication of the lower anterior crowns on teeth numbers 22-27, with cingulum rests and rest seat in tooth number 32 (Figure 2). After verifying the VDO with the new anterior restorations permanently seated, the next step in this stage was to seat single PFM units for teeth numbers 1 and 32.

Figure 2. Lower anterior laboratory case.

Verify VDO. The lower crowns were verified for proper VDO chairside and subsequently cemented and patient comfort in the adjusted vertical dimension was assessed prior to final cementation.

Cementation of restorations. After rechecking the new VDO with the new PFM crowns cemented on the mandibular anterior teeth and the PFM seated on teeth numbers 1 and 32, final impressions for the premium lower partial, with appropriate rest seats prepared on teeth numbers22, 23, 26, and 27 were made. This allowed for a recessed lingual bar to be used as a connector, instead of a lingual apron, with clasps and rest seat on tooth number 32 (Figure 3).

Figure 3a. Postoperative view, open mouth (note: without partial). 3b. Postoperative view, closed mouth (note: without partial).

Final impression. The final impression was made for fabrication of the lower cast metal framework with a resin base, replacing teeth numbers 18-21,and 28-31. Once the partial was obtained from the laboratory fabrication, the lower partial was seated, with the result of a stable, and securely seated, well-functioning appliance.

Deliver partial denture. The final partial denture was delivered to the patient, who readjusted to the new bite without any problems. Because no changes in mastication and phonetics had been detected by the patient with the temporary provisional crowns, the new bite created from the lower partial now allowed full intercuspation in centric relation.

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