Multidisciplinary management of advanced complexity tooth wear cases: patient needs beyond the direct and indirect restorations dichotomy

Pathological tooth wear affects a significant cohort of the population,^1,2 and has a known impact on the quality of life of patients, especially with regard to aesthetics and function.^3–6 Early diagnosis, prevention and stabilization are the fundamental stages in managing all tooth wear cases, with the provision of restorative treatment reserved as a last resort.^7–9 Nonetheless, restorative treatment is essential, and costly, for certain tooth wear cases, especially for those least able to afford it given the association between socio-economic status and tooth wear.^10,11

There is increased robustness in evidence supporting the different management modalities of tooth wear, be it direct or indirect resin composite through an additive approach, or ceramics through a subtractive one.^12–16 However, there remains a cohort of patients with complex clinical case presentations that require careful assessment, formulation of a multidisciplinary treatment plan, and the delivery of a restorative-led systematic intervention involving additional oral surgery or orthodontic specialties.¹⁷ This case series presents the multidisciplinary management of advanced complexity tooth wear cases, with treatment needs extending beyond the scope of direct and indirect restorative management, through a systematic treatment planning approach.

Case 1: Surgical and restorative intervention

A 54-year-old male presented with tenderness, and difficulty on biting, of his lower front teeth with progressing wear of these teeth over the previous 5 years (Figure 1). Main concerns were function and aesthetics. The patient found his occupation, as an air traffic controller, highly stressful. He reported a nail and pen-biting habit.

Multiple, intact, amalgam restorations were present on the posterior teeth. There was evidence of localized, moderate to severe tooth wear affecting the incisor teeth, and <2 mm remaining coronal tooth structure with exposed gutta percha noted for the mandibular incisor teeth. Calculus deposits and bleeding on probing (BoP) were present, with basic periodontal examination (BPE) scores of 1s and 2s. A thick gingival phenotype was present, and a reduced occlusal vertical dimension (OVD) noted. Radiographically, generalized horizontal bone loss (<15%), endodontically treated LL2–LR1, and lower incisors with short root lengths were noted (Figure 2).

Based on the remaining tooth structure and volume, interocclusal space and root length, the tooth wear case complexity was deemed as advanced.

Management aimed to address the underlying aetiology of tooth wear through behavioural modification and raising patient awareness of parafunctional habits, in addition to splint therapy (Table 1). Oral hygiene and improving periodontal status followed by a review were carried out. The rehabilitation phase aimed to create adequate prosthetic space for the restoration of the incisor teeth by increasing the OVD and reducing the mandibular alveolar ridge height for aesthetics and function (Figure 3). This was achieved through anterior direct resin-based composite restorations. Surgical crown lengthening was performed on LL3 and LR3 to improve ferrule and connector height relative to the adjacent ridge reduction (Figure 4). Given the poor prognosis of LL2–LR2, retained roots were extracted under local anaesthesia with alveolar ridge reduction completed to accommodate a LL3–LR3 metal-ceramic fixed partial denture (Figures 5 and 6). Posterior occlusal contacts were regained within 6 months through overeruption. An upper polymethyl methacrylate Michigan splint was provided for the patient, and a regular 6-month maintenance programme was recommended.

Case 2: Orthodontic, surgical and restorative intervention

A 42-year-old male was dissatisfied with the appearance of his teeth and reported difficulty chewing, having to habitually posture his lower jaw for the previous 5 years (Figure 7). The main concerns were aesthetics and function. Dietary analysis identified the patient's tendency to regular chew apple cores with seeds using his anterior teeth.

An Angle Class III malocclusion was present, resulting in an anterior crossbite. Localized, moderate to severe tooth wear was present on the maxillary central incisors, and mild to moderate tooth wear present on remaining anterior teeth. Early non-carious cervical lesions were noted on premolars. BPE scores of 1s and a thick gingival phenotype were noted. The UL2 was missing, and multiple, intact amalgam restorations were present on posterior teeth. Radiographically, there was generalized horizontal bone loss of <15% with a localized vertical defect present distal of UL6 (Figure 8).

Based on the high smile-line, remaining tooth structure and incisal relationship, the tooth wear case complexity was deemed as advanced.

Management entailed addressing the underlying tooth wear aetiology through behavioural modification, oral hygiene instructions and dietary advice (Table 2). Over a 2-year period, orthognathic maxillary advancement and orthodontic arch alignment was completed to provide a more favourable maxilla-mandibular relationship with a positive overjet, and create sufficient space for restoration of the tooth wear and UL2 (Figure 9). Surgical crown lengthening of UR3–UL3 was performed simultaneously with placement of a 3.3-mm diameter dental implant in the UL2 site (Figure 10). Of note, the volume of surgical crown lengthening resection was based on a diagnostic wax up, which, combined with prosthetic addition to the incisal edge, created the ideal height to width ratio. Following 3 months of healing, a provisional single-unit implant crown was connected, and the final orthodontic space closure was completed. The patient was debonded, and final direct resin-based composite additions were made to UR3–UL3 and LR1–LL1 in an occlusal confirmative approach (Figure 11). The UL2 implant was then definitively restored using a screw-retained zirconia crown with screw access sealed using polytetrafluoroethylene tape and composite (Figure 12). An Essix retainer was prescribed that doubled as a night guard, and a regular 6-month maintenance programme was prescribed.

Case 3: Surgical and restorative

A 52-year-old male complained of discomfort owing to his short and sharp teeth that had been progressively wearing down for 10 years, and he had become especially aware of this in the previous 2 years (Figure 13). His main concerns were aesthetics and long-term prognosis. Medically, he had type II diabetes and asthma. He had also experienced controlled gastro-oesophageal reflux disorder and had been prescribed omeprazole for more than 20 years. This condition was reviewed annually by his general medical practitioner. Dietary analysis revealed daily consumption of orange and grapefruit juices, with a tendency to swishing the juice before swallowing.

Class I skeletal pattern and occlusion, coinciding intercuspal position and retruded contact positions, canine guidance, and reduced OVD were present. Generalized moderate to severe tooth wear was present, with exposed dentine noted especially on the upper posterior teeth. BPE scores of 1s except for UL1–2, which presented with 5-mm periodontal pocket depths, thick gingival phenotype, and a high-smile line were detected. The clinical crown of the UL4 was rotated and compromised, with occlusal, mesial and distal surfaces lost, and a glass ionomer restoration covering the palatal surface. Radiographically, <20% generalized horizontal bone loss was noted, reduced crown height was evident on the upper posterior teeth, there was radiolucency under the UL4 restoration and on the mesial of UL7, a 4-mm short and poorly condensed obturation of UL6, and several pins on posterior upper teeth (Figure 14).

Based on the generalized tooth wear distribution, remaining tooth structure with circumferential enamel remaining, reduced inter-occlusal space, high-smile line, the tooth wear complexity of the case was deemed as intermediate to advanced.

Management of the case involved managing the underlying aetiology through behavioural modification to address the patient's dietary habits (Table 3). Oral hygiene instruction and non-surgical periodontal management followed. Thereafter, the UL6 was re-root canal treated given the quality of the presenting RCT and its guarded prognosis, which could jeopardize the overall management of the case. The UL4 was deemed unrestorable given the significant loss of tooth structure, recurrent caries, and tooth rotation, and subsequently extracted under local anaesthesia. After reassessing the oral hygiene, and caries and periodontal status, valid consent was reconfirmed. The rehabilitation stage involved composite build-ups completed on UR5–UL3 and LL3–LR5 followed by the early placement of an implant at UL4 (Figures 15 and 16). Lithium disilicate onlays were placed on upper and lower posterior teeth. The UL4 was replaced using an implant supported, screw-retained zirconia crown with a conventional loading protocol after 2 months of implant placement (Figure 17). Finally, on review, an upper PMMA stabilization splint and a maintenance plan was provided to the patient (Figure 18).

Discussion

The three clinical cases presented a multidisciplinary and systematic approach to planning and treating advanced complexity tooth wear patients. The interventions presented in this case series should not be interpreted as the sole treatment choice – other viable treatment options may be present. Managing such cases required surgical and orthodontic intervention in conjunction with a preventive and restorative one, and delivered over a considerable period. Determining whether the case is within the scope of the general dental practitioner, requires referral, or should be jointly managed, can be challenging.

One aspect worth discussing is the use of implant-supported crowns (ISC) in tooth wear patients. The use of ISC to restore spaces comes with several advantages, the most important being a fixed prosthetic alternative that preserves the tooth structure of abutment teeth lost in the case of fixed partial dentures. Nonetheless, implants placed in probable bruxers have a significantly higher risk of failure than for non-bruxers owing to mechanical complications.^18,19 While there is some evidence that occlusal overloading may help accelerate peri-implant disease in the presence of inflammation, there is no clear evidence that it instigates it.²⁰ To minimize the risk of such failures, occlusion must be carefully assessed, and the implant-supported prosthesis designed with an aim to reduce loading through sharing it with the remaining dentition as part of a mutually protected occlusion, avoiding or minimizing cantilevers, and having a shallow anterior guidance.²⁰ Accordingly, the presence of bruxism must be carefully assessed,²¹ and its risk must be disclosed to the patient as part of the valid consent process and factored in to the treatment plan through managing the underlying parafunctional habit, which may include behavioural modification, counselling, splint therapy, maintenance, and planning for future failure.^22,23

Using monolithic zirconia ISCs offers a viable treatment option with similar survival and failure rates, marginal bone loss and BoP to metal–ceramic (MC) ISC in the short term.²⁴ Nonetheless, chipping might still occur in patients with bruxism owing to occlusal loading, despite zirconia's overall reduced chipping rate compared to MC ISC.²⁵ Aesthetically, tooth wear patients appear to be satisfied with the appearance of their anterior monolithic zirconia crowns and would choose the same treatment again.²⁶ When restoring posterior teeth in tooth wear patients, opting for adhesively bonded monolithic lithium disilicate (LS2) onlays at an increased OVD also appears to be a viable treatment modality, and a more aesthetic option to gold onlays. In vitro testing that involved modelling bruxism through lateral static loading showed that, while zirconia demonstrated the highest resistance to failure with a main mode of failure being debonding, LS2 came in second and was more durable than zirconia-reinforced lithium silicate (ZLS) and polymer-infiltrated ceramic network (PICN), with their main mode of failure being fracture.^27,28 The limited clinical evidence seems to support the use of LS2 as a reliable treatment option in severe tooth wear cases with a reported 100% survival rate and no reports of biological complications, debonding, or recurrent caries at an up to 11-year follow-up period.¹⁵ Similarly, limited but promising clinical evidence supports the general use of ZLS, with a 99% survival rate at 1 year and PICN restorations with a survival of 99.2% at 2 years.²⁹

Orthodontic therapy should be considered in cases presenting with malocclusion, to improve clinical crown height and to facilitate restorative space creation through a prosthetically driven orthodontic approach.^30,31 Diagnostic wax-ups or intra-oral mock-ups offer a valuable diagnostic aid for treatment planning.³² This joint planning becomes even more critical in tooth wear patients who present with aesthetics as their main concern to achieve a satisfactory outcome for the patient.^33,34

Formulating a rigorous maintenance stage as part of the treatment plan ensures long-term success of the overall treatment, especially in patients with extensive restorative work.³⁵ Communicating and emphasizing this life-long need for monitoring, and the possible need for future intervention, is essential and forms part of the valid consent process. The use of splint therapy in patients reporting bruxism offers significant benefits in protecting the patient's dentition and restorative work³⁶ and in reducing muscle activity during sleep bruxism.^37,38 It is also worth noting that the choice of splint material is also important owing to its wear of the opposing surfaces. If the opposing dentition is intact with tooth surfaces in enamel or restored using composite or LS2, a heat-cured PMMA splint may offer better durability.³⁹ However, if the opposing surface is dentine, then a chemically cured PMMA splint should be considered.

Conclusion

Management of advanced complexity tooth wear cases to restore aesthetic and functional damage that occurred over many years must involve careful assessment, case-selection, and a systematic, multidisciplinary approach to treatment planning.