Full mouth restorative rehabilitation of the generalized worn dentition: a step-by-step approach to treatment

It has been suggested that the application of any tooth wear index should not be a major influence as to whether restorative treatment should be provided.¹ Several patient and clinician factors must be taken into consideration and carefully evaluated before restorative intervention is prescribed. Patient factors would include:¹

• Pain or sensitivity;
• Functional issues, e.g. chewing, eating and/or phonetics;
• Aesthetic concerns;
• Patient concerns about the longevity of restorations and/or teeth owing to their diminished structure or the rate of deterioration.

The clinician on the other hand, may have primary or secondary concerns.^1,2 Primary concerns might be:

• The amount of tooth wear present;
• The affected surfaces;
• The number of teeth affected.

While secondary concerns would include:

• The pattern and rate of tooth surface loss;
• The age of the patient;
• The likely aetiological factors.

In addition to the above, the impact of tooth wear on the patient's psychosocial condition also needs to be considered.³ Oral health-related quality of life factors and the psychological impact on wellbeing following aesthetic rehabilitation need evidence-based appraisal before restorative treatment is commenced.⁴ Meticulous patient assessment and history taking will be required.⁵ Treatment cost, complexity, prognosis and maintenance will require inclusion into the patient consent process.^3,6,7 Where no adverse effects are recorded due to the tooth wear, effective prevention and periodic monitoring of the condition could be the indicated management strategy.^4,7,8

The observed increase in the incidence of tooth wear, particularly in the younger population, with the implications for future problems, also needs to be considered.^9–11

For any restorative approach to tooth wear, an effective prevention regimen is fundamental to success.¹² Its implementation is dependent upon the clinicians' timely assessment of the severity, aetiology, and risk factors.^12,13 Guidelines for risk assessment and prevention are available in the UK.^13,14 However, Mehta et al¹⁵ reported inconsistencies among UK and non-UK dentists with respect to carrying out risk assessments for tooth wear and using indices for routinely recording tooth wear. Therefore, consideration needs to be given for a timely diagnosis concurrent to the assessment of the risk factors that would contribute to the continuation of the tooth wear.

A pragmatic alternative while considering the aetiological factors for tooth wear can be summarized as in Figure 1.^12,16

With tooth wear having a multifactorial aetiology, the primary factor can sometimes be established as being either chemical or mechanical,¹⁷ and an effective preventive regimen applied accordingly.¹² Often however, a combination of both factors may be involved and this may compound the preparation of an effective preventive plan and further vigilant monitoring of the rate of wear progression may be required to tailor the preventive prescription, as necessary.

Systematic reviews have suggested that currently there is no evidence that one material is superior to another for the restorative treatment of generalized tooth wear.^9,18 Guidelines have been proposed¹ that restorative treatment should be as conservative as possible. Minimally invasive treatment strategies should be employed while considering a dynamic restorative treatment concept. The application of adhesive concepts to bond to both enamel and dentine, with direct and indirect materials, is advocated.¹ Any tooth preparation should be restricted to the creation of necessary features, including seats, bevels or chamfers, to facilitate restoration placement. Materials and techniques should be selected considering the expectations, aesthetic demands, and risk profile of the patient. Operator familiarity and skills are important factors, as is patient availability for recall, and any budgetary constraints.¹

A workflow that addresses the patient's adaptation and expectations to the prescribed increase in the vertical dimension of occlusion, as well as the aesthetic changes, is recommended. During this process, the use of materials that can be easily adjusted has distinct advantages. In this context, the use of dental composite has benefits.^19–21 Aesthetic and functional prescriptions can be confirmed, and adjustments made if indicated.^7,16,22 Furthermore, it is of key importance that this treatment modality may be applied with minimal intervention. Not only will contingency options be available, but there is additional scope to preserve as much residual tooth tissue as possible – a key goal when planning the rehabilitation of the worn dentition. Subsequent replacement of the directly applied composite resin restorations with more resilient or aesthetic alternatives can then be considered.^7,22,23

Clinical steps for the restorative rehabilitation of the generalized worn dentition

Step 1: aesthetic evaluation

For patients who present with an aesthetic or functional concern regarding their generalized tooth wear, the intended outcome should be presented to the patient for evaluation before the restorative treatment is commenced. This can be done digitally, via wax-ups on study models, or using a combination of these techniques. It is preferable that the patient is able to appraise this intra-orally.

Figures 2 and 3 show the extra- and intra-oral images of a male patient who was aged 47 years at presentation with generalized tooth wear and who complained of sensitivity and had aesthetic concerns. A labial diagnostic wax-up was constructed on study models for this patient. Consideration was given to the desired increase in crown length, as well as the labial contour of the teeth (Figure 4).

At this stage, only the aesthetic parameters were considered.²⁴ Using a putty index, the wax-up was transferred onto the patient's anterior teeth to check the aesthetic parameters and for the patient to assess the intended aesthetic outcome (Figure 5).

Step 2: determination of the restorative space

Once the aesthetic evaluation has been performed and approved by the patient, the next step is to determine the inter-occlusal space required for the rehabilitation. The considerations for the space required between the teeth in the maxillary and mandibular arch include the aesthetic requirements, as well as the need for enough space for the proposed restorative material to ensure that the restorations offer the required mechanical properties. The occlusal principles have been documented.^26–28 Often however, the centric relation recording does not allow for the required space as seen in the case shown in Figure 6.

In the authors' opinion, if the inter-occlusal space is deemed insufficient or excessive to requirements when assessed on articulated study models, then the temptation to increase or reduce the vertical dimension by setting the incisal pin of the articulator to achieve the required separation should be resisted. Reducing or increasing the vertical height to the required amount on the articulator can result in significant inaccuracies introduced into the diagnostic wax-up. This is due to the difference in the arc of closure and opening between the articulator member and the patient's own mandible. Therefore, the inter-occlusal record should be re-recorded clinically to represent the required separation of the upper and lower teeth. Figure 7 shows a different case where the upper and lower models have been mounted at the intended restorative vertical dimension and the wax-up constructed according to this clinically determined restorative height. The condylar elements of the semi-adjustable articulator can be set at average values unless lateral records are taken to programme the articulator. In most cases average values will suffice.

Step 3: the adjustable restorative transfer

There are various techniques and materials described in the literature for the aesthetic and functional transfer of the determined parameters to the patient's dentition. Using a material that can be adjusted, allowing the patient to adapt to and accept the aesthetic and functional changes, has some clear benefits, allowing the patient to ‘test drive’ the planned aesthetic–functional prescription using minimally invasive treatment techniques. For the case shown in Figures 2–6, the restorative transfer was achieved using direct composite resin restorations for the treatment of worn posterior teeth and mandibular anterior teeth, while the anterior maxillary teeth were restored using laboratory-fabricated indirect composite restorations. While the available clinical data typically focus on the performance of a given material or application technique for the treatment of tooth wear, as seen by this case example, it is not uncommon in contemporary clinical practice to use a variety of different materials and application techniques, which may better suit the presenting requirements, not only at arch level, but at tooth level too. A transparent silicone index was constructed for the posterior teeth from the posterior diagnostic wax-up (Figure 8).²⁹Figure 9 shows how these indices were used to place the direct composite on the posterior teeth. Figure 10 shows the composites added to the posterior teeth. Note that the composite material at the patient's LR7 is acting as an occlusal stop owing to the presence of a previous amalgam restoration at that tooth.

Figure 11 shows the space that is available for the restoration of the maxillary and mandibular anterior teeth following the addition of the posterior direct composite. The mandibular anterior teeth were then built up with a direct composite material using a lingual putty matrix, which was constructed from the mandibular diagnostic wax-up (Figure 12). For this patient, depicted in Figures 2 and 3, laboratory-fabricated indirect composite material was chosen and cemented onto the anterior teeth as shown in Figure 13.³⁰Figure 14 shows the frontal view after all the restorations had been cemented and just prior to the final polishing.

Direct composite can also be considered for build-up of anterior teeth as shown in Figure 15. The resultant occlusal scheme of a mutually protective occlusion (MPO) with posterior disclusion on mandibular protrusive and lateral movements is preferred. In certain cases, while building up the occlusal surfaces of the worn posterior teeth, a flatter occlusal morphology can be considered to facilitate developing the occlusal stops. The latter can be seen by the case shown in Figure 16.

Step 4: patient adaptation and adjustments

The patient is now allowed time to adjust to the new restorative position and confirm the aesthetic outcome. Adjustments can be made as necessary. Thus a ‘patient centric’ occlusion is achieved, which can then be transferred on to more resilient or aesthetic materials as necessary in step 6.

Step 5: monitoring and review

The favourable performance of direct (anterior and posterior) composites for the restoration of severe, generalized tooth has been well documented. In one study, among a sample of 1269 restorations that included those in higher risk patients, with follow-up beyond 5 years, annual failure rates of less than 3% were reported with very few catastrophic failures.²⁰ However, repair and refurbishment may be required.

Careful case planning and the timing of intervention are also critical to a successful outcome with this approach,²¹ as are good operator skills and knowledge. A recent study has also alluded to the improvement in the patient's perception of the aesthetic outcome falling full-mouth rehabilitation of the worn dentition with resin composite 5 years post-treatment.³¹ When planning care, it is not only appropriate to discuss the likely prognosis of the restorations, but also the benefits the patient may hope to expect in terms of potential gains in their quality of life.^4,31 Often, at this step, continued monitoring of the tooth wear is recommended, with the use of indices and standardized photographs.³² Digital technology may also have a role to play.³³

Step 6: future material replacements

Composite restorations require maintenance and can be repaired, if required. The patient will need to be aware of this requirement as part of the initial consent process. When being repaired, because the patient has adapted to the changes that were initially prescribed, a decision can be made to replace the composite with more aesthetic or resilient materials (Figure 17).^7,16

Conclusions

A step-by-step approach to generalized tooth wear restorative management provides a sound basis for a predictable outcome. It allows for a systematic approach whereby the patients expectations, consent, adaptability, and future desires can be addressed and monitored.