Restorative Management of Constriction and Spacing Following Arch Expansion

An adult patient presented with esthetic concerns related to anterior spacing, progressive incisal wear, and intermittent jaw symptoms despite prior orthodontic expansion. Although alignment and arch form had improved as a result of the orthodontic therapy, the patient continued to experience nighttime waking related to morning jaw tightness, discomfort, and functional instability. A comprehensive evaluation revealed a constricted chewing pattern (CCP) contributing to localized anterior attrition and ongoing symptoms, along with elevated periodontal and biomechanical risks. Using Kois Center diagnostic principles, a systematic treatment approach was developed to address functional limitations, manage risk, and achieve the patient’s esthetic goals.^1,2 The vertical dimension of occlusion (VDO) was increased in a predictable manner, creating restorative space to re-establish appropriate overjet, improve the envelope of function, and conservatively restore worn anterior teeth.³

Clinical Case Overview

A 63-year-old female patient presented for evaluation in December 2024 with concerns regarding anterior spacing, worn incisal edges, discolored teeth, and intermittent jaw symptoms (Figure 1 through Figure 3). She reported nighttime waking due to jaw discomfort, periodic morning tightness, and a sense that her bite “continued to change,” despite having completed orthodontic treatment aimed at expanding the dental arches, particularly in the maxilla—ie, miniscrew-assisted rapid palatal expansion (MARPE), followed by surgically facilitated orthodontic therapy (SFOT), which was performed at a different practice.

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Her primary goals were threefold: reduce jaw discomfort and nighttime symptoms, close anterior spacing and restore worn incisal edges, and achieve a natural-looking, brighter smile.

Given the patient’s complex medical, periodontal, and dental history, a comprehensive evaluation was performed to assess periodontal, biomechanical, functional, and dentofacial risks. This systematic approach revealed persistent CCP and guided the development of a phased treatment plan focused on functional stability, risk management, and conservative restorative care.

Medical History

The patient’s medical history included controlled hypothyroidism, osteoporosis, depression, digestive issues, high blood pressure, and severe obstructive sleep apnea (OSA). Her OSA was treated with maxillary expansion and was determined by a follow-up sleep study to have been resolved. A former smoker, the patient’s past medication history included bisphosphonate use. She had discontinued both the smoking and bisphosphonate use 10 years prior. Current medical history included intermittent sleep disturbances that caused jaw pain, contributing to frequent nighttime awakenings. Due to her past history of OSA, she was retested, and the follow-up study did not demonstrate any recurrence.

Dental History

In addition to the aforementioned previously performed orthodontic treatment, the patient reported a history of gingival bleeding and discomfort during brushing and flossing. She also described an unpleasant taste in the mouth that included metallic and burning sensations. A history of tooth sensitivity to hot, cold, biting, and sweets was noted, along with periods during which she avoided brushing certain areas due to discomfort. She further reported a history of food impaction between teeth.

Additionally, the patient reported prior experiences of teeth feeling crowded, becoming looser, and spaces forming between teeth over time. She indicated that she had previously placed her tongue between her teeth, pushed against her teeth, and bitten her cheeks and lips. She also noted habitually squeezing her teeth together, tapping her teeth, and shifting her jaw to make her back teeth fit together. A history of nail biting and chewing ice was also reported.

The patient had a history of jaw joint pain, discomfort, and tightness, most commonly noted in the morning and occasionally during the daytime. She also reported a history of daytime and nighttime clenching and grinding.

Diagnosis, Risk Assessment, and Prognosis

Periodontal: Periodontal records from 2021 through 2024 demonstrated a progressive pattern of breakdown. In 2021, probing depths were primarily 3 mm to 4 mm throughout the posterior dentition. Subsequent examinations revealed a gradual increase in probing depths, with 2024 measurements showing posterior probing depths predominantly in the 4 mm to 5 mm range in both the maxillary and mandibular arches.

In 2024, maxillary posterior probing depths measured 3 mm to 4 mm buccally and 3 mm to 5 mm lingually, while mandibular posterior probing depths were 4 mm to 5 mm, with lingual sites consistently exhibiting deeper readings. Gingival recession was noted on the posterior teeth, measuring approximately 3 mm to 4 mm in the maxillary posterior region and 2 mm to 3 mm in the mandibular posterior region.

Periodontal examination revealed class I furcation involvement on tooth No. 3 and class II furcation involvement on teeth Nos. 2, 3, 14, 15, 18, and 30. Generalized tooth mobility ranging from grade 1 to grade 2 was observed. The most recent periodontal evaluation in 2024 demonstrated generalized bleeding on probing in the posterior dentition, indicating active periodontal inflammation.

The patient reported consistent periodontal care, including scaling and root planing when indicated and routine prophylaxis at 6-month intervals. Based on the observed disease progression and current clinical findings, a 3-month periodontal maintenance interval was recommended in coordination with her periodontist.

Given the extent of posterior pocketing, recession, furcation involvement, and evidence of disease progression over time, the patient was classified as American Academy of Periodontology (AAP) stage III, grade B,⁴ with consideration for stage IV based on the complexity of management. To reiterate, the patient would undergo active periodontal therapy and be placed on a strict periodontal maintenance protocol under the supervision of her periodontist before proceeding with definitive restorative care.

Risk: High

Prognosis: Poor

Biomechanical: No erosion, active caries, or defective restorations were identified. Existing restorations included a large composite restoration on tooth No. 14 that was structurally compromised due to excessive isthmus width (Figure 4), an amalgam restoration on tooth No. 18, and a full gold crown on tooth No. 31 (Figure 5).

Incisal attrition of 1 mm to 1.5 mm was observed on teeth Nos. 7 through 10 and 23 through 26. Posterior morphology was preserved, and no posterior abrasion was present. The patient reported no sensitivity or xerostomia. The localized anterior wear pattern with preserved posterior morphology was consistent with a CCP rather than generalized attrition (Figure 4 and Figure 5).

Risk: Moderate

Prognosis: Posterior teeth fair; anterior teeth poor

Functional: The patient denied episodes of jaw locking or limited opening but reported a history of jaw tightness upon waking and nighttime waking due to jaw discomfort. She acknowledged a history of daytime clenching and denied prior use of occlusal appliances.

Functionally, the patient reported that her teeth had become noticeably shorter over the past 5 years, accompanied by increased crowding and the development of spacing. Her oral habits included chewing ice, biting nails or objects, and daytime clenching, all of which are known to increase functional load on the dentition and temporomandibular joints.

Clinically, the presence of localized anterior attrition with preserved posterior morphology suggested that functional forces were concentrated anteriorly rather than evenly distributed across the arch. The patient’s report of progressive anterior chipping, combined with clenching behaviors and limited anterior clearance, indicated that her habitual maximum intercuspation likely constrained the functional envelope. This constrained functional position plausibly contributed to increased loading of the anterior teeth and stress on the temporomandibular joints, manifesting as morning jaw tightness and intermittent joint discomfort.

Additionally, the patient reported sleep disturbances, including nighttime waking associated with jaw awareness, further supporting a functional component to her symptoms.

Taken together, the patient’s reported symptoms, functional habits, and clinical wear pattern were consistent with CCP.¹

Risk: Moderate

Prognosis: Fair, with functional stabilization and monitoring

Dentofacial: The patient desired a brighter, yet natural, smile with less visible gum tissue when smiling and the restoration of chipped incisal edges. Her Duchenne smile revealed a hypermobile lip displaying all her maxillary teeth and more than 4 mm of gingival tissue. Most of the gingival exposure, however, occurred in the posterior dentition, while the gingival display of the maxillary anterior teeth (Nos. 7 through 10) remained within an acceptable esthetic range. Therefore, periodontal surgical intervention such as crown lengthening was not indicated, and the existing gingival architecture was preserved.

Risk: High

Prognosis: Poor

Treatment Plan and Sequencing

Treatment was phased using established principles to address the patient’s functional limitations while optimizing esthetics and minimizing biomechanical risk.^1,2 Dentofacial reference glasses (Kois Facial Reference Glasses, Kois Center, koiscenter.com) and digital photography were used for accurate dentofacial esthetic analysis (Figure 6).^5-7 Although her previous orthodontic therapy had improved spacing and alignment, functional instability persisted due to the CCP. Further maxillary expansion was limited by biologic constraints; therefore, treatment focused on restoring functional clearance through a controlled increase in VDO.

Phase 1: Diagnostics and Functional Deprogramming

Comprehensive diagnostics were performed following the previously performed orthodontic treatment. A Kois deprogrammer was delivered to eliminate neuromuscular engrams and establish a repeatable centric relation (CR).⁷ Upon deprogramming, the mandible consistently repositioned anteriorly, resulting in a near edge-to-edge incisal relationship, confirming inadequate anterior clearance in the patient’s habitual maximum intercuspation.

With the deprogrammer in place, digital intraoral scans of the maxillary and mandibular arches were obtained, along with a digital interarch relationship record. To ensure accuracy and redundancy, a polyvinyl siloxane (PVS) bite registration (Jet Bite, Coltene, coltene.com) was also captured. After evaluation, the bite record was selected for definitive restorative planning due to its stability and repeatability.

Using these records, the dental laboratory fabricated a comprehensive diagnostic wax-up of the maxillary and mandibular arches at the planned increased vertical dimension.

Phase 2: Maxillary Restorative Phase

Treatment began with the maxillary arch to establish esthetics, anterior guidance, and occlusal reference prior to mandibular preparation. The maxillary teeth were prepared conservatively in an additive manner (Figure 7), guided by the diagnostic wax-up. Final impressions were made using a heavy- and light-body PVS impression system (3M™ Express™ VPS Impression Material and 3M™ Impregum™ Penta™ Soft Heavy Body, 3M, 3m.com). Provisional restorations were fabricated using a laboratory-generated putty matrix and delivered to evaluate esthetics, phonetics, and function (Figure 8).

At the completion of this phase, the patient was dismissed with both maxillary and mandibular provisional restorations in place, allowing for full-arch functional evaluation. This provisionalization established and introduced the planned P2 position, providing a controlled environment to assess occlusal stability, anterior guidance, and patient adaptation prior to definitive mandibular treatment.

The patient returned for delivery of the definitive maxillary zirconia restorations (Prettau® 3 Dispersive®, Zirkonzahn, zirkonzahn.com) on teeth Nos. 2 through 15. The fit, esthetics, and occlusal stability at the new vertical dimension were verified. The intaglio surfaces of the zirconia crowns were cleaned after try-in to remove any saliva contamination using a cleaning paste (Ivoclean® Universal Cleaning Paste, Ivoclar, ivoclar.com). The material was applied with a microbrush and thoroughly rinsed to remove phosphate contaminants.

After cleaning, a single-component adhesive primer (Clearfil™ Ceramic Primer Plus, Kuraray Noritake, kuraraynoritake.com) was applied to the intaglio surfaces and air-dried according to manufacturer recommendations.^7,8

The restorations were cemented using a self-adhesive resin cement (RelyX™ Unicem 2, 3M) (Figure 9). Excess cement was removed following tack-curing.

Phase 3: Mandibular Stabilization and Posterior Preparation

Following delivery of the maxillary restorations, it was essential to confirm mandibular positioning in CR prior to initiating mandibular preparations. A temporary anterior deprogramming platform was bonded to the mandibular anterior teeth using composite resin (Figure 10), allowing the patient to function in CR for several days.⁹ The patient was instructed to maintain a soft diet during this period to facilitate neuromuscular adaptation.

After this adaptation period, the patient returned for mandibular treatment, having demonstrated successful adaptation to the new vertical dimension established during the maxillary and mandibular provisional phase. The mandibular posterior provisional restorations were removed, and posterior preparations were completed first (Figure 11). A posterior bite registration was taken to preserve the established CR position. Subsequently, the mandibular anterior teeth—including the deprogramming platform—were prepared, and an anterior bite registration was captured in conjunction with the posterior record (Figure 12). Final mandibular impressions were then obtained, and the mandibular provisionals were seated with a dual-cure, temporary, resin-based cement with triclosan (Temp-Bond™ Clear™, Kerr, kerrdental.com) (Figure 13).

Phase 4: Final Restoration Delivery, Cementation, and Occlusal Equilibration

The mandibular zirconia restorations were seated in the same manner as was done in the maxillary arch (Figure 14). Occlusal equilibration was then performed in a deliberate, sequential manner. Initial evaluation was completed using 200-µm horseshoe articulating paper to identify gross frictional contacts, which were selectively adjusted. A thinner (8-µm) articulating paper was subsequently used to refine occlusal contacts, with attention paid to contacts on inclines and cusp slopes. Finally, shimstock foil (Almore International, almore.com) was used to verify contact intensity and uniformity, ensuring stable posterior support without premature loading or occlusal interferences. Adjustments were made until balanced contacts were achieved at the established CR and VDO.

Phase 5: Maintenance and Follow-up

Given the patient’s periodontal and functional risk profile, a 3- to 4-month periodontal maintenance interval was recommended in coordination with her periodontist. Each recall visit would include evaluation of occlusal stability, periodontal health, and restoration integrity.

Discussion

This case illustrates how esthetic concerns can mask underlying functional constraints, particularly CCP. Although the patient had previously undergone orthodontic expansion—primarily to widen the maxillary arch—the expansion did not fully resolve the biomechanical limitations of her chewing envelope. The maxillary arch could only be expanded to a biologically and periodontally safe limit; beyond that threshold, additional expansion would have compromised stability or soft‑tissue support. As a result, despite improved alignment, the patient remained functionally constricted.

During deprogramming with the Kois deprogrammer, the patient’s true neuromuscular position became evident. Once relaxed out of her habitual occlusion, her mandible consistently shifted forward, placing her in an edge‑to‑edge incisal relationship. This was a key diagnostic moment, as it confirmed that the patient was functioning in a constricted pattern and that her habitual occlusion was masking an underlying discrepancy between tooth position and functional envelope.

Given this forward mandibular repositioning, a predictable restorative strategy required increasing the VDO to allow several critical objectives to be met simultaneously. These objectives included: (1) re‑establishing appropriate overjet to accommodate the patient’s functional chewing path and prevent repeated incisal collisions; (2) restoring functional space for an unrestricted anterior envelope of function; (3) enabling an additive restorative approach, thus minimizing tooth reduction and preserving remaining tooth structure; (4) enhancing esthetics, allowing elongation and refinement of the anterior teeth without encroaching on envelope boundaries; and (5) closing residual anterior spacing to unify esthetics and function.

By increasing VDO in a controlled, deprogrammer‑validated manner (maxillary arch was increased by approximately 1.5 mm at the incisal edge; mandibular arch was increased by approximately 1 mm), the final tooth position was designed to harmonize with the patient’s true functional movements rather than her habitual constrained position. This approach created stable occlusion, improved comfort, and beautiful esthetics (Figure 9, Figure 14 through Figure 17), with a durable foundation for long‑term periodontal and biomechanical health.¹⁰

The selection of a zirconia-based rehabilitation in this case, versus a minimally invasive composite or lithium-disilicate approach, is also worth noting. The restoration choice is inherently nuanced and reflects a balance between preservation of tooth structure and long-term functional stability. While a direct composite approach would represent the least invasive option for increasing vertical dimension, it was not selected in this case because of concerns regarding long-term stability in a full-arch rehabilitation. Restoring multiple posterior units with composite can present challenges in achieving consistent proximal contacts, maintaining occlusal precision, and ensuring durable marginal integrity, particularly in patients with elevated functional risk.¹¹

Partial-coverage lithium-disilicate restorations, such as onlays and minimally invasive anterior veneers, could have been a viable alternative, as this approach may have reduced the need for restorative intervention while maintaining favorable esthetics. However, given the extent of functional reorganization required, including the management of a CCP and increased vertical dimension, the decision to use zirconia in this case prioritized long-term durability and occlusal stability. Zirconia provided a predictable solution with high strength, resistance to wear, and minimal thickness requirements, allowing for controlled execution of the treatment plan in the context of this patient’s functional risk.^12-14 Alternative, more conservative strategies remain appropriate in selected cases depending on clinician experience, patient expectations, and risk tolerance.

Conclusion

By integrating systematic diagnostics, deprogramming, and careful vertical dimension management, this case achieved both esthetic and functional rehabilitation for a patient with CCP. Conservative multilayered zirconia restorations, sequenced occlusal planning, and disciplined maintenance support long-term stability and patient comfort.

ABOUT THE AUTHOR

Michael An, DDS

Private Practice specializing in Cosmetic Dentistry, Irvine, California

Figures and Images

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Figure 1

Pretreatment, full-face smile.

Figure 2

Pretreatment, close-up view of patient’s smile.

Figure 3

Pretreatment, retracted view; note uneven anterior spacing, worn and chipped incisal edges, and discolored teeth.

Figure 4

Pretreatment, maxillary occlusal view.

Figure 5

Pretreatment, mandibular occlusal view.

Figure 6

Patient wearing facial reference glasses for accurate dentofacial esthetic analysis.

Figure 7

Preparation of maxillary teeth done in an additive manner.

Figure 8

Provisional restorations of maxillary teeth.

Figure 9

Delivery of definitive maxillary zirconia restorations.

Figure 10

Temporary anterior deprogramming platform designed to confirm mandibular positioning in CR.

Figure 11

Preparation of mandibular teeth, starting in the posterior.

Figure 12

Bite registration was captured.

Figure 13

Occlusal view of mandibular provisionals.

Figure 14

Occlusal view of mandibular definitive zirconia restorations.

Figure 15

Post-treatment, close-up view of patient’s smile.

Figure 16

Post-treatment, retracted view demonstrating exceptional esthetics.

Figure 17

Post-treatment, full-face smile.