Porcelain Laminate Veneers: Adjunctive Treatment of Occlusal Disorders

Porcelain Laminate Veneers: Adjunctive Treatment of Occlusal Disorders

As “smile makeovers” with laminate veneers become increasingly popular, responsible clinicians must carefully assess each patient for possible contraindications. As this case demonstrates, additional treatment may be required to provide patients with both the smile they desire as well as long-term success. Due to functional and biomechanical issues, this case might have had a poor outcome without detailed data collection and a systematic approach to treatment planning.¹

Clinical Case Overview

Patient History and Chief Complaint: A 42-year-old woman with fair oral hygiene presented seeking esthetic improvement. She had recently finished an 18-month course of orthodontics to address a joint click and to improve the appearance of her smile (Figure 1 through Figure 3). The results, however, had left her dissatisfied; she believed the orthodontics had failed to improve the overall appearance of her smile, and her temporomandibular joint click was still present.

Her medical history was unremarkable, apart from a known allergy to penicillin. Her dental history, meanwhile, revealed no periodontal or biomechanical problems, but she indicated that she experienced clicking jaw joints, that her jaws became tired when speaking, and that she avoided chewing gum or sticky foods. She also said that she needed to squeeze her teeth to make them fit together. These complaints all indicated the presence of unacceptable function, with a possible chewing envelope constriction or an occlusal dysfunction.

Diagnostic Findings, Risk Assessment, and Prognosis

Panoramic (Figure 4), bitewing, and cephalometric radiographs were taken. Analysis of her cephalometric radiograph revealed a Class III tendency with retroclined lower incisors. No abnormal extraoral findings were noted. Intraoral findings included: the presence of several small-to-medium–sized composite restorations; bonded retainers present on the lingual surfaces of the upper and lower anterior teeth (Figure 5); the upper and lower incisors slightly retroclined; and an Angle Class I molar relationship.

The examination revealed normal range of motion and a click in both temporomandibular joints. Both the load and immobilization tests were negative. Fremitus was observed during light tapping of the teeth. The anterior teeth held shimstock foil when the patient occluded in her habitual maximum intercuspal (MIP) position.

Finally, with the patient seated upright at 45 degrees, she was asked to reproduce normal chewing motions while a piece of 200-µm-thick articulating paper was held in place. Streaks were noted on the lingual surfaces of the upper anteriors where the bonded orthodontic retainers were placed.

Periodontal: Periodontal examination showed very slight tissue inflammation, minimal bone loss, and periodontal pocket depths of < 3 mm on most teeth. Localized 4-mm pocket depths were noted around the upper molars. The diagnosis was AAP type II.

Risk: Low

Prognosis: Good

Biomechanical: Questionable composite restorations were present on teeth Nos. 3, 6 through 11, 18, 19, 30, and 31. Small chips were observed on Nos. 24 and 25; No. 32 was partially erupted but was noncarious, and the patient was able to clean it (Figure 4).

Risk: Moderate

Prognosis: Good for all unrestored teeth; fair for teeth with restorations

Functional: Further diagnostic steps were required for appropriate functional assessment. After consultation with an orthodontist, a decision was made to remove the upper bonded retainer and fit the patient with a Kois deprogrammer (Figure 6) to determine whether the apparent chewing envelope constriction was caused by the retainer or was the result of her tooth position, in which case the patient would need to return to orthodontic therapy prior to veneer placement. Two weeks later, after deprogramming was confirmed, bite records and a Kois LAZRTRAK (Kois Center, www.koiscenter.com) facebow record were taken and the casts mounted using a Panadent articulator (Panadent, www.panadent.com).

Analysis revealed that the patient’s envelope of function was not constricted, as her mandibular position moved slightly posterior, with premature contacts noted in the bicuspid areas on the left side. The patient also stated that her bite felt significantly improved as soon as the bonded retainer was removed, noting that her back teeth finally touched properly. The “constriction test” with the 200-µm articulating paper was repeated, with a negative result: no streaks were found on the anterior teeth.

The final diagnosis was occlusal dysfunction, and the patient was treatment-planned for occlusal equilibration.

Risk: Moderate

Prognosis: Fair

Dentofacial: Dentofacial analysis revealed a tooth–arch size discrepancy. Also noted was that the diastemas in the upper anterior segment had previously been closed with composite bonding but had re-opened after the orthodontic treatment, and the dental midline was canted and not parallel to the facial midline. Lip dynamics were medium, and tissue scallops were average. A slight tissue asymmetry was noted on tooth No. 10, and tissue zeniths were slightly malpositioned in teeth Nos. 8 and 9.

While lip mobility is the main determinant of dentofacial risk, the risk for this patient was slightly increased due to her very high esthetic expectations.

Risk: Moderate

Prognosis: Fair

Treatment Goals

The overall treatment goals were to meet the patient’s esthetic concerns without increasing either her biomechanical or functional risks. This involved: 1) minimal removal of sound tooth structure to avoid a change in biomechanical risk; and 2) treating the occlusal dysfunction to decrease functional risk.

Treatment Plan

After careful consideration of all treatment options, the patient elected the following treatment plan: In keeping with functional goals, feldspathic porcelain veneers would be placed on teeth Nos. 4 through 13, which would provide long-lasting restorations with minimal sacrifice of sound tooth structure. To address biomechanical issues, existing questionable composite restorations on teeth Nos. 3, 18, 19, 30, and 31 would be replaced. In addition, recontouring of tissue would be performed on teeth Nos. 8 through 10, while the opposing teeth would be bleached to achieve an overall lighter shade.

While the patient agreed to occlusal equilibration, she believed that her bite had been corrected once the bonded upper retainer was removed and was eager to proceed with her veneer restorations as soon as possible. Therefore, she insisted that the occlusal equilibration needed to ensure longevity of her porcelain veneers be done after veneers were fitted, and was willing to accept the risk that she might chip a veneer before achieving equilibration due to the avoidance patterns created by her posterior interferences.

Treatment Phases

Phase 1: Periodontal Therapy, Bleaching, Composite Restoration

The patient received periodontal therapy consisting of scaling and root planing and was fitted with a bleaching tray for the lower arch only. The desired bleaching outcome was achieved after 4 weeks. The veneer preparation appointment was scheduled for 4 weeks after the patient stopped bleaching to let the shade “settle” and to avoid potential problems with adhesion.²

The questionable composite restorations on teeth Nos. 3, 18, 19, 30, and 31 were replaced.

Phase 2: Tissue Contouring

Gingival recontouring was carried out in one session. The tissue was first reshaped on teeth Nos. 8 through 10 with a diode laser, and then the crestal bone was recontoured in a closed procedure with a Wedelstadt bone chisel, as gingival levels can only be predictably altered once crestal bone levels are addressed.³

Phase 3: Restorative Treatment

The dental laboratory created an additive diagnostic wax-up⁴ that incorporated all the patient’s desired esthetic improvements. When the patient returned for the “trial smile” appointment,⁴ a putty index made from the wax-up was loaded with a bis-GMA temporary material (Luxatemp®, DMG America, www.dmg-dental.com) and placed in the patient’s mouth. The patient then verified that all desired improvements were addressed (Figure 7).

Preparation Appointment

At the preparation appointment, shade selection, using the VITA Easyshade® (Vident™, www.vident.com) and 3D Master Shade Guide (Vident), was done prior to any other procedures to avoid dehydration of the teeth and improper shade matching.

After anesthesia was administered, bone sounding was performed. The patient primarily had a “normal crest,” with readings of 4 mm in the interproximal and 3 mm on the facial; therefore, the risk of recession or biologic width violation was minimal, assuming appropriate margin placement. However a slight “high crest” situation was noted on the facial aspects of teeth Nos. 9 and 13, with readings of 2.5 mm.⁵

A Sil-Tech® matrix (Ivoclar Vivadent, Inc, www.ivoclarvivadent.com) was loaded with bis-GMA and transferred to the patient’s mouth. Once the bis-GMA was set, it functioned as a reduction guide to minimize tooth reduction in a “prep through technique” as described by Magne⁶ and others (Figure 8).

Thus, the entire preparation was kept in enamel, without increasing either the biomechanical or pulpal risk. After placement of a size 00 retraction cord, the preparations were finalized with fine diamonds, carrying the finishing lines just slightly under the free gingival margin, and angling the incisal edges lingually to allow the technician to hide the incisal edge.⁷ Extreme care was taken to not cause biologic width violation on teeth Nos. 9 and 13. A vinylpolysiloxane (VPS) impression was taken using a standard two-cord technique.

A bite record and facebow record with the Kois LazrTrak were taken. The preparation shade was chosen, then communicated to the laboratory with numerous photographs. The putty matrix was filled again with bis-GMA to produce provisionals, which were fitted using a light-cured, clear temporary cement.

Once the patient approved the provisionals, photographs and study models were taken for laboratory communication.

Try-in Appointment and Cementation

At the try-in appointment, the patient was first anesthetized, then provisional restorations were removed, and temporary cement residue was cleaned off using air abrasion. The veneers were silanated,⁸ then tried in with water to assess fit. Color match was assessed in both natural and artificial light using various try-in pastes and photographs. Once the patient approved them for cementation, the intaglio surfaces were cleaned with 37% phosphoric acid and thoroughly rinsed. The prepared teeth were cleaned once again using air abrasion with 27-μm aluminum oxide at low pressure (40 psi), and size 00 cord was gently packed into the sulcus.

After isolating the adjacent teeth with teflon tape, teeth Nos. 8 and 9 were etched for 15 seconds using 37% phosphoric etch and rinsed thoroughly. Excess water was removed using only cotton gauze to prevent over-drying of the preparations. Two coats of bonding agent (Adper™ Single Bond, 3M ESPE, www.3MESPE.com) were placed on the prepared teeth, then the veneers were loaded with veneer cement (RelyX™ Veneer Cement, 3M ESPE) and seated on the teeth using apical and inward pressure. Most excess cement was immediately wiped away using microbrushes. The veneers were “tacked” into place with an initial cure of the cement to a rubbery stage, allowing for easy removal of residual cement. Glycerin gel was applied to all margins for oxygen inhibition, and final curing was carried out for 40 seconds on all surfaces.⁹ The same steps were repeated for the remaining veneers, fitting them two at a time.

Retraction cords were removed, and final cement removal was accomplished using 12B scalpel blades, a hand scaler, and waxed floss. Margins were polished using a brownie point. Occlusion was checked and a final polish of the veneers was carried out using porcelain polishing paste and a felt disc.

At the end of the appointment, impressions for a new Kois deprogrammer—to be fitted 1 week later—were taken.

Phase 4: Functional After-Care

The Kois deprogrammer was fitted, as planned, 1 week after veneer placement. The patient returned 2 weeks later for her equilibration appointment, during which deprogramming was confirmed and equilibration was carried out using football-shaped diamonds and brownie points. At the end of the equilibration appointment, the patient admitted that she had not known that her teeth “could fit together that well” (Figure 9).

Although the patient’s reciprocal joint click was present after equilibration, it had never been associated with pain and continued to be stable.^10,11 The patient was appointed for final photographic and radiographic documentation (Figure 10 through Figure 14).

Conclusion

This case demonstrates the need to be vigilant in planning cases, carefully taking functional challenges into account. The patient said she was delighted with her veneers and felt reassured knowing that her occlusal problems had been addressed. As a result of detailed, careful planning, the patient’s prognosis for excellent longevity of the restorations is significantly improved.

ACKNOWLEDGMENT

The author would like to thank and recognize Harald Heindl, MDT, Aesthetic Dental Creations, Mill Creek, Washington, for outstanding laboratory support and ceramic fabrication.

ABOUT THE AUTHOR

Sandra Hulac, DDS
Private Practice, Hong Kong, China

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