Phased Correction of a Worn Dentition With a Severe Occlusal Cant Using a Systematic Management System

When planning and executing a complex case, use of a systematic tool to identify, assess, and manage risk can aid clinicians in achieving treatment goals. This case report illustrates the correction of a severe occlusal cant and restoration of a worn dentition using phased digital treatment planning and the 10-Step Kois Management System© (Kois Center, koiscenter.com). As demonstrated in this case, clinical findings were first gathered and diagnoses were determined. Then, after completion of a risk analysis and prognosis, the phased treatment plan was created. The 10-step management system was used to segment the treatment planning process, beginning with the horizontal and vertical positioning of the maxillary and mandibular  teeth (steps 1 through 6), followed by management of the functional (step 7) and gingival considerations (steps 9 and 10).

A 73-year-old man presented for a new-patient examination. His chief concerns were restoring his worn teeth, maintaining function, and keeping costs within his budget. Among the challenges with which this patient presented were the management of his severe occlusal cant (Figure 1 and Figure 2) and the sequencing of treatment to meet his financial needs. The patient was informed of the available choices for restorative materials and their longevity along with the overall risks and prognoses of treatment options. A full-mouth rehabilitation plan was presented to the patient that included opening his vertical dimension of occlusion (VDO) to accommodate the necessary restorative space.^1,2 The treatment would be staged over 6 months to make it more affordable for the patient.

The patient's medical history included a history of high blood pressure, chronic leukemia, and melanoma. The only medication he was currently taking was for blood pressure. The severe erosion noted in his dentition raised a concern about gastroesophageal reflux disease (GERD) (Figure 3 and Figure 4). After extensive review of both his medical history and dietary and beverage consumption, it was determined the erosion was a result of dietary exposure, as the patient reported a history of drinking black coffee "all day" at work for 30 years. Management of dietary acids, therefore, would be critical to the longevity of any dental work.

The patient's dental history included moderate anxiety surrounding dental treatment due to completion of dental work without anesthetic as a child.

Periodontal: The patient was classified as American Academy of Periodontology (AAP) stage I, with no periodontal probings over 3 mm and generalized horizontal bone loss of less than 2 mm, grade B (Figure 5).

Risk: Low

Prognosis: Good

Biomechanical: There was active decay on teeth Nos. 5, 7, 9 through 11, and 29. Generalized severe erosion was present on teeth Nos. 4 through 13, 20, 21, 28, and 29. The patient had moderately worn teeth (1 mm to 2 mm) on teeth Nos. 22 through 27.

Risk: High; five areas of decay were noted

Prognosis: Poor to hopeless

Functional: The patient's function was deemed acceptable, as there were six questions regarding function in his dental history (Kois Center) that were answered negatively. The patient reported no issues with chewing hard, crunchy, or chewy foods. He also reported that his teeth fit together well without any shifting. His temporomandibular joint (TMJ) examination was normal with no popping or crepitus. The joint accepted full loading and did not have any pain with immobilization tests. As erosion was outpacing frictional wear, function was acceptable.

Risk: Low

Prognosis: Good

Dentofacial:In the patient's Duchenne smile, only a small amount of gingival tissue was showing above teeth Nos. 10 and 11 (Figure 6). There was inadequate visual tooth length of the central incisors as tooth No. 8 measured 5.7 mm and No. 9 measured 6.2 mm. Esthetic average length is 10 mm.³ The maxillary left canine was at the "0" position in repose (Figure 7).⁴

Risk: Low to moderate

Prognosis: Good to fair

The overall treatment goals were to restore function and improve the esthetics and long-term prognosis of the decayed and eroded teeth. The patient was ready to proceed with comprehensive treatment and understood the need to "open" his bite. After the patient was advised of the risks and benefits of injectable composites versus ceramic restorations, a combination of both was ultimately chosen. Injectable composites can be considered for a final restorative option, especially in the anterior teeth, or for a transitional restoration prior to completing ceramic restorations. Posterior injectable composites have a lifespan of approximately 3 to 5 years depending on multiple factors, such as material thickness and enamel bonding versus bonding to another restorative material.⁵

Once the appropriate vertical dimension and esthetics were established, the clinician could proceed with treatment in phases to accommodate the patient's financial limitations.

The treatment plan would be carried out in five phases:

Design a facially driven treatment plan utilizing digital records.

Verify the proposed digital design by creating a trial smile to confirm esthetics and correction of the occlusal cant.

Restore the maxillary arch with both indirect restorations and injectable composites. The biocopy feature of CEREC^® (Dentsply Sirona, dentsplysirona.com) would be utilized to copy the design of the premolars from the diagnostic mock-up. The diagnostic mock-up would also be used as a reduction guide for the anterior teeth.

Stabilize the occlusion until the patient was ready to restore the mandibular teeth by placing composite turbos⁶ on the mandibular bicuspids prior to restoring the mandibular arch.

Restore the mandibular arch with both indirect restorations and injectable composites. The biocopy feature of CEREC would again be utilized to copy and transfer the premolar design.

Phase 1: Records and Analysis

Digital planning was used for the diagnostic mock-up. Preoperative photographs were taken (Figure 1, Figure 3, Figure 4, Figure 8, and Figure 9). Facial reference glasses (Facial Reference Glasses, Kois Center, koiscenter.com) were used for the dentofacial analysis and digital facebow mounting.⁷ Using the facial reference glasses and natural head posture allowed visualization and planning for correction of the horizontal plane of the maxillary arch.

Digital impressions of the maxillary and mandibular arches were taken using an intraoral scanner (iTero Element^™, Align Technology, Inc., itero.com). Centric relation was established with a Lucia jig, and a digital bite record was obtained. All the records were uploaded to a digital hub (Evident Hub, Evident, evidentdigital.com). The first step in the dentofacial analysis was to determine the maxillary incisal edge position. A reliable reference for this is the visual position of the maxillary canine in repose.⁴ Based on the dentofacial analysis, which showed the maxillary left canine at the "0" position from the upper lip in repose, the decision was made to level the incisal edges of teeth Nos. 6 through 11 (Figure 10). Next, the maxillary posterior teeth Nos. 12 through 14 and 3 through 5 were leveled to the horizontal plane.

The mandibular incisal edge position was determined in the same manner as the maxillary incisal edge position as described above and also by using the Kois Dento-facial Analyzer (Kois Center), and the decision was made to add 1.5 mm to the incisal edge of tooth No. 22. The incisal edge of this tooth was used as a horizontal reference to level teeth Nos. 22 through 27. The occlusal surfaces of teeth Nos. 19 through 21 and 28 through 30 were built up to this same horizontal plane.

Phase 2: Manufacture of the Proposed Digital Design and Completion of a Trial Smile

The digital hub (Evident Hub) was used to create and print the proposed restorative design for the maxillary and mandibular arches. A model was printed, then a polyvinyl siloxane (PVS) matrix was created for the maxillary arch. When the patient returned for the esthetic try-in, provisional composite (Luxatemp^®, DMG America, dmg-america.com) was injected into the matrix and seated. The esthetic try-in revealed that the maxillary cant had not been completely corrected. Again utilizing the digital hub, tooth No. 6 was lengthened by an additional 1 mm, and the maxillary plane was then leveled to that addition. The mandibular mock-up required an adjustment to accommodate the addition to the maxillary arch, and the clinician approved the esthetics of the revised mock-up.

Phase 3: Restoration of the Maxillary Arch

The diagnostic mock-up was placed on the maxillary teeth using the aforementioned provisional composite (Luxatemp). The mock-up was sectioned at the distal aspects of teeth Nos. 4, 6, 11, and 13. Teeth Nos. 4, 5, 12, and 13 were prepared for full-coverage lithium-disilicate restorations (IPS e.max^®, Ivoclar, ivoclar.com). The biocopy tool in CEREC was utilized to copy the diagnostic mock-up for the premolar teeth. The diagnostic mock-up was sectioned and removed for data input. The e.max crowns were fabricated and cemented with resin cement (RelyX^™ Unicem 2, 3M Oral Care, 3m.com). Injectable composite was added to teeth Nos. 3 and 14.

A clear matrix was fabricated (EXACLEAR^™, GC America, gc.dental/america) using the diagnostic mock-up referencing teeth Nos. 4, 5, 12, and 13. Teeth Nos. 3 and 14, which were restored with a full gold crown and a porcelain-fused-to-metal crown, respectively, needed mechanical retention. Therefore, the occlusal surfaces were prepared with a diamond bur and then air-abraded. Clear matrices were placed, and a universal injectable composite (G-aenial^™ Universal Injectable, GC America) was injected and cured with curing lights (Demetron^® Kerr Dental, kerrdental.com).

Next, the diagnostic mock-up was placed on the maxillary anterior teeth as a reduction guide to prepare the anterior teeth for full-coverage e.max crowns (teeth Nos. 6 through 11). The final impressions were completed with PVS material (Take 1^® Advanced^™ VPS Impression Material, Kerr Dental) and sent to the laboratory. Using the diagnostic mock-up, temporaries were fabricated with Luxatemp and cemented with a non-eugenol temporary dental cement (Temp-Bond^™, Kerr Dental). When the patient returned for the delivery appointment, the e.max restorations for teeth Nos. 6 through 11 were tried in and esthetics were verified by both the patient and clinician. Lastly, the e.max crowns for these teeth were cemented with RelyX Unicem 2 translucent cement.

Phase 4: Stabilization of Occlusion to Phase Treatment

The mock-up was then placed on the mandibular teeth and sectioned to facilitate the placement of composite turbos on teeth Nos. 20, 21, 28, and 29 to stabilize the occlusion prior to restoring the mandibular arch.

Phase 5: Restoration of the Mandibular Arch

The diagnostic mock-up was placed on the mandibular teeth utilizing the provisional composite (Luxatemp). The mock-up was sectioned at the distal aspects of teeth Nos. 20, 22, 27, and 28. Teeth Nos. 20, 21, 28, and 29 were prepared for full-coverage lithium-disilicate crowns (IPS e.max). As was done in the maxillary arch, the biocopy tool in CEREC was utilized to copy the diagnostic mock-up for the premolar teeth. In this instance, the diagnostic mock-up had to be sectioned and removed so the computer would be able to stitch together the data correctly.

The e.max crowns were fabricated and then cemented with resin cement (RelyX Unicem 2) (Figure 11). The injectable composite technique was again utilized on teeth Nos. 19 and 30. A clear matrix was fabricated (EXACLEAR) from the diagnostic mock-up using teeth Nos. 20, 21, 28, and 29 as references. Teeth Nos. 19 and 30, which were previously restored with full gold crowns, would need mechanical retention to hold the composite in place. The occlusal surfaces were prepared with a diamond bur and then air-abraded. Clear matrices were placed, and a universal injectable composite (G-aenial) was injected and cured with curing lights (Demetron). A clear matrix was fabricated (EXACLEAR) from the diagnostic mock-up utilizing Nos. 20, 21, 28, and 29 as reference teeth. Injectable composite technique was used to restore the worn mandibular anterior teeth Nos. 22 through 27. The universal injectable composite (G-aenial) was injected into the matrix and cured using curing lights (Demetron).

The occlusion was finalized using a deprogrammer on the lingual aspect of teeth Nos. 8 and 9. The patient was placed in a 45-degree position in the dental chair, and the composite was reduced until posterior equal bilateral simultaneous contacts were achieved. Any remaining material on the lingual aspects of teeth Nos. 8 and 9 was removed and the lingual surfaces were polished. The patient was then seated in an upright position in the chair to simulate chewing cycles. Lateral streaks were marked on and removed from teeth Nos. 7 through 10 using 200-µm articulating paper (Bausch, bauschpaper.com).

The clinician was able to achieve good functional occlusion and improve esthetics, and the patient was very happy with the results (Figure 12 through Figure 17). Correcting the cant of the maxillary arch proved challenging, as the patient's smile asymmetry made it difficult to assess. At the time of this writing, the patient continues as an active patient in the practice and is seen for routine recare visits. The posterior injectable composite restorations will need to be monitored for breakdown and replaced as needed to maintain the restored occlusion.

Utilizing the 10-Step Kois Management System to plan and execute this complex case, the clinician first gathered clinical findings and completed diagnoses. A risk analysis and prognosis was then done, and the phased treatment plan was created. The treatment planning process was able to be segmented, beginning with the horizontal and vertical positioning of the maxillary and mandibular teeth, followed by management of the gingival and functional considerations. This system proved invaluable in treatment planning for this patient's severe cant, and use of a deprogrammer during the restoration delivery simplified management of the occlusion. The ability to phase treatment in the worn dentition not only allowed the patient to consider more comprehensive treatment options, but also enabled him to move forward with treatment that fit into his budgetary constraints.

The author thanks Evident, Frontier Dental, and Susan Sheets, DDS.

Christine Hansen, DDS
Clinical Instructor, Kois Center, Seattle, Washington; Diplomate, American Academy of Dental Sleep Medicine; Private Practice, Palo Alto, California