Mehta SB, Loomans BAC, Banerji S An investigation into the impact of tooth wear on the oral health related quality of life amongst adult dental patients in the United Kingdom, Malta and Australia. J Dent. 2020; 99 https://doi.org/10.1016/j.jdent.2020.103409
Wazani BE, Dodd MN, Milosevic A The signs and symptoms of tooth wear in a referred group of patients. Br Dent J. 2012; 213 https://doi.org/10.1038/sj.bdj.2012.840
Mehta SB, Loomans BAC, van Sambeek RMF Managing tooth wear with respect to quality of life: an evidence-based decision on when to intervene. Br Dent J. 2023; 234:455-458 https://doi.org/10.1038/s41415-023-5620--4
Mehta SB, Banerji S The restorative management of tooth wear involving the aesthetic zone. Br Dent J. 2018; 224:333-341 https://doi.org/10.1038/sj.bdj.2018.174
Eliyas S, Martin N The management of anterior tooth wear using gold palatal veneers in canine guidance. Br Dent J. 2013; 214:291-297 https://doi.org/10.1038/sj.bdj.2013.273
Loomans B, Opdam N, Attin T Severe tooth wear: European consensus statement on management guidelines. J Adhes Dent. 2017; 19:111-119 https://doi.org/10.3290/j.jad.a38102
Mehta SB, Banerji S, Millar BJ, Suarez-Feito JM Current concepts on the management of tooth wear: part 2. Active restorative care 1: the management of localised tooth wear. Br Dent J. 2012; 212:73-82 https://doi.org/10.1038/sj.bdj.2012.48
Suarez Feito J, Mehta SB, Banerji S Full mouth restorative rehabilitation of the generalized worn dentition: a step-by-step approach to treatment. Dent Update. 2023; 10:707-709 https://doi.org/10.12968/denu.2023.50.10.834
Zonnenberg AJJ, Türp JC, Greene CS Centric relation critically revisited-What are the clinical implications?. J Oral Rehabil. 2021; 48:1050-1055 https://doi.org/10.1111/joor.13215
Gracis S Clinical considerations and rationale for the use of simplified instrumentation in occlusal rehabilitation. Part 1: Mounting of the models on the articulator. Int J Periodontics Restorative Dent. 2003; 23:57-67
Hardan L, Mancino D, Bourgi R Treatment of tooth wear using direct or indirect restorations: a systematic review of clinical studies. Bioengineering. 2022; 9 https://doi.org/10.3390/bioengineering9080346
Ramseyer ST, Helbling C, Lussi A Posterior vertical bite reconstructions of erosively worn dentitions and the ‘stamp technique’ – a case series with a mean observation time of 40 months. J Adhes Dent. 2015; 17:283-289 https://doi.org/10.3290/j.jad.a34135
Opdam N, Skupien JA, Kreulen CM Case report: a predictable technique to establish occlusal contact in extensive direct composite resin restorations: the DSO-technique. Oper Dent. 2016; 41:S96-S108 https://doi.org/10.2341/13-112-t
Mehta SB, Lima VP, Bronkhorst EM Clinical performance of direct composite resin restorations in a full mouth rehabilitation for patients with severe tooth wear: 5.5-year results. J Dent. 2021; 112 https://doi.org/10.1016/j.jdent.2021.103743
Mehta SB, Bronkhorst EM, Lima VP The effect of pre-treatment levels of tooth wear and the applied increase in the vertical dimension of occlusion (VDO) on the survival of direct resin composite restorations. J Dent. 2021; 111
Milosevic A, Burnside G The survival of direct composite restorations in the management of severe tooth wear including attrition and erosion: A prospective 8-year study. J Dent. 2016; 44:13-19 https://doi.org/10.1016/j.jdent.2021.103712
Hoekstra-van Hout PMJ, Schols JGJH, Mehta SB Posterior dahl: a minimally invasive method for the treatment of localized posterior tooth wear. J Adhes Dent. 2023; 25:31-38 https://doi.org/10.3290/j.jad.b3837959
Bartlett D, Varma S A retrospective audit of the outcome of composites used to restore worn teeth. Br Dent J. 2017; 223:33-36 https://doi.org/10.1038/sj.bdj.2017.583
Gulamali AB, Hemmings KW, Tredwin CJ, Petrie A Survival analysis of composite Dahl restorations provided to manage localised anterior tooth wear (ten year follow-up). Br Dent J. 2011; 211 https://doi.org/10.1038/sj.bdj.2011.683
van Sambeek RMF, de Vos R, Crins LAMJ Perception of oral health related quality of life and orofacial aesthetics following restorative treatment of tooth wear: A five-year followup. J Dent. 2023; 136 https://doi.org/10.1016/j.jdent.2023.104626
Sterenborg BAMM, Kalaykova SI, Knuijt S Speech changes in patients with a full rehabilitation for severe tooth wear, a first evaluation study. Clin Oral Investig. 2020; 24:3061-3067 https://doi.org/10.1007/s00784-019--03174-7
Schlichting LH, Resende TH, Reis KR Ultrathin CAD-CAM glass-ceramic and composite resin occlusal veneers for the treatment of severe dental erosion: An up to 3-year randomized clinical trial. J Prosthet Dent. 2022; 128:158.e1-158.e12 https://doi.org/10.1016/j.prosdent.2022.02.009
Vailati F, Gruetter L, Belser UC Adhesively restored anterior maxillary dentitions affected by severe erosion: up to 6-year results of a prospective clinical study. Eur J Esthet Dent. 2013; 8:506-530
Crins LAMJ, Opdam NJM, Kreulen CM Randomized controlled trial on the performance of direct and indirect composite restorations in patients with severe tooth wear. Dent Mater. 2021; 37:1645-1654 https://doi.org/10.1016/j.dental.2021.08.018
Maier E, Crins L, Pereira-Cenci T 5.5-yearsurvival of CAD/CAM resin-based composite restorations in severe tooth wear patients. Dent Mater. 2024; 40:767-776 https://doi.org/10.1016/j.dental.2024.03.001
Oudkerk J, Herman R, Eldafrawy M Intraoral wear of PICN CAD-CAM composite restorations used in severe tooth wear treatment: 5-year results of a prospective clinical study using 3D profilometry. Dent Mater. 2024; 40:1056-1063 https://doi.org/10.1016/j.dental.2024.05.015
Edelhoff D, Erdelt KJ, Stawarczyk B, Liebermann A Pressable lithium disilicate ceramic versus CAD/CAM resin composite restorations in patients with moderate to severe tooth wear: Clinical observations up to 13 years. J Esthet Restor Dent. 2023; 35:116-128
Burian G, Erdelt K, Schweiger J In-vivowear in composite and ceramic full mouth rehabilitations over 3 years. Sci Rep. 2021; 11 https://doi.org/10.1038/s41598-021-93425-z
Smales RJ, Berekally TL Long-term survival of direct and indirect restorations placed for the treatment of advanced tooth wear. Eur J Prosthodont Restor Dent. 2007; 15:2-6
Milosevic A, Burnside G The survival of direct composite restorations in the management of severe tooth wear including attrition and erosion: A prospective 8-year study. J Dent. 2016; 44:13-19 https://doi.org/10.1016/j.jdent.2015.10.015
Hammoudi W, Trulsson M, Svensson P, Smedberg JI Long-term results of a randomized clinical trial of 2 types of ceramic crowns in participants with extensive tooth wear. J Prosthet Dent. 2022; 127:248-257 https://doi.org/10.1016/j.prosdent.2020.08.041
Lima VP, Crins LAMJ, Opdam NJM Deterioration of anterior resin composite restorations in moderate to severe tooth wear patients: 3-year results. Clin Oral Investig. 2022; 26:6925-6939 https://doi.org/10.1007/s00784-022-04647-y
Restoration of the worn dentition using aesthetic dental materials: an evidence-based guide to technique and material selection Shamir B Mehta Subir Banerji Jose Suarez Feito Bas AC Loomans Dental Update 2024 1:3, 707-709.
Authors
Shamir BMehta
BDS, BSc
BDS, BSc, MClin Dent (Prosth), Dip FFGDP (UK), PhD, FCGDent, FDSRCPS (Glas), FDSRCS (Eng), FDTFEd (RCSEd), FHEA, Programme Director MSc in Aesthetic Dentistry, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London; Visiting Professor, Department of Dentistry, Radboud University Medical Centre, Nijmegen, Netherlands
BDS, MClinDent (Prostho), PhD MFGDP(UK), FDS RCPS(Glasg), FICOI, FICD, FIADFE, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London; Professor, School of Dental Health and Care Professions, University of Portsmouth; Associate Professor, Department of Prosthodontics, Melbourne Dental School, University of Melbourne; Private Practice, Ealing, London
MD, BSc, MClinDent (Prostho), MSc, PhD, Visiting Professor, International University of Catalunña; Visiting Professor for Masters in Periodontics, University of Oviedo; Private Practice, Oviedo, Spain
There are several techniques and dental materials that can be used for the restorative rehabilitation of the worn dentition. Currently, however, there is the lack of clear scientific data to support the superiority of any given approach. An evidence-based overview is presented in this article, to help clinicians navigate this difficult decision-making process.
CPD/Clinical Relevance:
This article collates the research, aiming to appraise the current techniques and materials available for the restorative rehabilitation of the worn dentition.
Article
Tooth wear is an increasing concern in dentistry. When severe, it can significantly diminish a patient's quality of life, often as a result of aesthetic changes.1,2 Consequently, some patients may seek restorative care to address their aesthetic needs.
Restorative rehabilitation for worn dentitions is complex, time-consuming, and expensive, requiring ongoing maintenance and review once initiated. Therefore, in the absence of functional concerns or patient demand, it may be improper to recommend extensive restorative treatment. For patients with moderate to severe pathological wear, the likelihood of future restorative intervention can be higher. As such, counselling, preventive measures and monitoring should be prioritized as the first approach.3 Effective management of the underlying causes is crucial to prevent premature failure of any restorative work.
Dentists must understand when and how to address tooth wear. The timing of restorative rehabilitation is complex and requires consideration of the extent of the damage, symptoms, wear progression, and the impact of the presentation the patient's quality of life.4 This article provides insights into how current evidence-based approaches can guide treatment planning, including technique selection and material choice for managing the worn dentition.
Planning the restorative management of tooth wear: the essential concepts
Restorative intervention becomes necessary when the wear poses significant concerns for the patient or clinician, particularly if there are functional or aesthetic issues, or if the patient experiences pain or discomfort. In such cases, the timing of restorative treatment should be a collaborative decision between the clinician and the patient.
Achieving a satisfactory outcome with the restorative rehabilitation of tooth wear requires careful consideration of several key aspects. These include the following.
Smile design
Restoring the aesthetics of a worn dentition, particularly in the smile zone is challenging owing to limited reference points from the pre-worn dentition and the subjective nature of beauty. Therefore, practitioners must have a firm understanding of the universally accepted concepts in dental aesthetics, including disease elimination, symmetry, proportion, harmony, tooth position, dental morphology, colour variations, and gingival aesthetics, as outlined by Mehta and Banerji.5
To establish a definitive aesthetic prescription, an initial ‘intra-oral mock-up,’ may be performed, where unbonded resin composite is placed to assess alterations to tooth size and shape. Alternatively, digital smile evaluation (DSE) tools may be used.
Occlusal planning: generalized and localized tooth wear
Maintaining the functionality of the masticatory system often involves dento-alveolar compensation following tooth wear, which typically results in insufficient inter-occlusal space to accommodate restorative materials. This space can be created through subtractive tooth preparation or by placing restorations in a supra-occlusal position. The latter may involve increasing the vertical dimension of occlusion (VDO) and/or by adopting a reorganized approach, using any space between the centric relation contact point (CRCP) and the intercuspal position (ICP).
The mutually protected occlusal scheme (MPO) is commonly the preferred occlusal restorative concept, particularly in full-mouth rehabilitations for generalized tooth wear and in localized treatments that require subsequent occlusal adaptation.6 While long-term studies allude to the absence of a difference between canine-guided occlusion and group-function occlusion in terms of patient comfort and restoration longevity,7 the former occlusal scheme is generally favoured (assuming the canines are in good condition) because it is technically simpler to achieve than a group-guided occlusal scheme.6
To add or to subtract
In line with the philosophy of the European Consensus Statement on Management Guidelines,8 restorative intervention should prioritize a conservative, ‘additive’ approach over a ‘subtractive’ one whenever possible. This strategy minimizes the unnecessary loss of healthy tooth tissue and reduces the risk of pulp pathology associated with conventional, mechanically retained restorations. Employing a minimally invasive, additive approach also supports contingency planning, allowing for the option of conventional restorations later, once the patient has adapted to the new functional and aesthetic outcomes provided by the initial additive and adjustable treatment.
Material selection and clinical techniques
The clinician must have sound knowledge of the available dental materials and techniques, including concepts in adhesive dentistry and traditional prosthodontic protocols. Logically, the process of attaining consent must consider the risks, the benefits, and the likely prognosis of the appropriate reasonable treatment options. This will require a good working knowledge of the available evidence base. This is discussed below.
The use of direct resin composite restorations for the additive, adhesive rehabilitation of worn teeth, as supported by the European Consensus Statement on the Management Guidelines (for Severe Wear), has been advocated as the initial treatment of choice, offering multiple merits,8 as discussed below.
Planning a functional aesthetic wax-up
Before initiating the wax-up, it is essential to confirm the occlusal prescription with an estimate of the required increase in the VDO at the desired horizontal occlusal position. The goal is to restore the original tooth size and length, provide sufficient bulk of restorative material for durability, and ensure adequate occlusal support in both anterior and posterior regions along with addressing the aesthetic issues of the patient. The condition of the most worn tooth or teeth can serve as a useful guide.
For cases of generalized tooth wear, clinicians traditionally use dental casts mounted in centric relation (CR) in the least using a semi-adjustable articulator,9 adjusting the pin to create sufficient space. However, as Suarez Feito et al10 point out, altering the vertical height on the articulator can introduce inaccuracies owing to differences in the arc of closure between the articulator and the patient's mandible.11 For this reason, an opinion has been expressed that CR registration should be attained at the desired new restorative VDO.12 The importance of the CR position therefore needs to be critically re-evaluated and the feasibility of a more ‘patient centric’ occlusal dimension and prescription needs to be established.
Using the above information with the outcomes of the assessment of the aesthetic zone, the dental technician can create a diagnostic wax-up, which should then be verified by taking an impression of the wax-up and transferring it to the patient's mouth using a provisional crown and bridge resin materials. Alternatively, a ‘clip-on smile’ can be fabricated indirectly.
Material and technique selection
Once the functional aesthetic prescription and the new VDO have been established using a wax-up, it is crucial to accurately transfer this information for the definitive restoration of tooth wear. This can be achieved through both direct and indirect techniques. However, it is important to note that there is currently no clear evidence favouring one type of dental material or specific application technique (direct or indirect) for the treatment of tooth wear.13,14
Despite careful planning, there is always the potential risk that the patient may not accept or tolerate the proposed changes. The use of direct composite is particularly beneficial in this context, as it offers a minimally invasive way to ‘test-drive’ the planned changes. This technique allows for easy intra-oral adjustments, whether adding or removing material, enabling realtime refinement based on the patient's feedback and using their stomatognathic system as a physiological ‘dental articulator.’ This approach helps to fine tune the treatment to better meet the patient's needs. In extreme cases, the composite material can be removed with minimal harm to the underlying dental tissues, provided no significant tooth preparation was involved in its application.
The performance of direct resin composite restorations for the treatment of tooth wear: the available evidence
Various techniques for the direct application of resin composite in the treatment of tooth wear have been documented. These methods include freehand application, matrix-guided techniques that involve creating a ‘negative’ of the occlusal prescription as determined by a wax-up, and the ‘stamp technique.’15 Additionally, the direct shaping by occlusion (DSO) protocol offers a comprehensive approach for full-mouth treatment of worn dentitions,16 alongside several moulding techniques. Figure 1 shows a patient case of the restoration of tooth wear using direct composite, where an injection moulding technique was used owing to financial limitations; however, full consent was given.
figure 1.
(a) A 58-year-old patient with generalized tooth wear. The aetiology was multifactorial, a combination of chemical and mechanical challenges. Aesthetic and functional complications were present because of the compensatory eruption of the anterior teeth, especially the maxillary incisors, leading to short clinical crowns, reduced restorative space, and an impinged envelope of function (EOF). Before the restorative intervention, orthodontic treatment was prescribed to improve the position of the anterior teeth and the lower arch's arch form. (b) Once the pre-restorative orthodontic objectives were achieved, restorative reconstruction was carried out using injected flowable composites because of the economical limitations of the patient (after explaining the merits and demerits of the procedure). (c) Follow-up at 3.5 years, showing the absence of wear facets or any significant chippings and acceptable colour stability. Note the lack of initial characterization at the groves of the occlusal surfaces.
Regardless of the chosen application method, a minimum thickness of 1.5–2.0 mm of restorative material is recommended. This thickness is crucial to meeting functional demands and achieving optimal performance.
Approximately 20 investigations have been published reporting the outcomes of the clinical performance of direct resin composite for the restoration of tooth wear. Studies including sample sizes of over 1000 restorations have been discussed in more detail below.
A systematic review reported the mean annual failure rates (AFRs) for direct resin composite restorations for the treatment of tooth wear to range from 0.7% (‘good’) to 26.3% (‘unacceptable’). The use of micro-filled materials compared to micro-hybrid resin composites was associated with higher failure risk.13
In a study of 1269 direct resin composite restorations placed in 34 patients with severe generalized tooth wear applied by experienced operators, AFRs of less than 3% over a period of 5.5 years were reported.17 Only 29 restorations exhibited catastrophic failure. Notably, premolar restorations were twice less likely to fail compared to molar restorations, although catastrophic failures among molars were rare. For anterior restorations, the need for additional composite material in subsequent appointments (for occlusal or aesthetic refinement) significantly increased the risk of failure. Therefore, it may be advisable to avoid adding further material in later appointments whenever possible, and instead ensure that an adequate amount of material is initially applied.
As a follow up to the above study, using information from the same sample of restorations,18 higher levels of anterior tooth wear (pre-treatment) were associated with increased levels of failure of the direct composite restorations. Progressive loss of enamel tissue from tooth wear may have been influential, owing to the predictability of bonding to this tissue. Patients must be advised of the risk of delaying treatment when the need has been established. This study also showed a clear protective effect on the failure of the anterior restorations by an increase in the VDO by 1 mm. Providing thicker/more voluminous direct composite restorations while concomitantly respecting the presenting aesthetic and biological parameters is likely to benefit performance. This may be owing to the enhanced fracture resistance of the restorations. Ensuring appropriate layer thickness of composite resin restorations is essential to the longevity of the restoration, where in general, resin composite restorations do not perform well in sections of less than 1.5–2.0 mm thickness. Fracture is the most common failure type encountered in the restoration of worn dentition using direct resin composite, manifesting as cohesive failures at the restoration margins and chipping. It is also important to ensure the use of an effective bonding protocol and appropriate materials for dental adhesion.
Another investigation of the survival of 1010 direct resin composite restorations placed in 164 patients (primarily at anterior maxillary teeth using the Dahl approach) reported an overall failure rate of 7% at around 34 months (mean AFR of approximately 2.5%).19 The lack of posterior support was identified as a significant factor contributing to failure. Most of the failures took place during the first-year post-treatment. Given that the restorations were mostly placed in supra-occlusion, it is not surprising that higher initial failure rates were observed, as demonstrated in this study, perhaps a result of the occlusal separation of the residual dentition, where the functional restorations are initially subjected to higher mechanical loads until occlusal contacts are re-established.
Favourable clinical success and patient satisfaction has also been reported with direct posterior composite restorations placed using the Dahl concept for the treatment of localized posterior tooth wear.20
However, successful outcomes with the use of direct composite for the treatment of tooth wear have not been consistently reported.21,22 Bartlett and Varma reported that 17% of their restorations failed (n=251) where the outcomes were monitored for up to 14 months.21 Variations in treatment outcomes using this modality of care may relate to the levels of pre-treatment tooth wear, the primary aetiology (mechanical or chemical) and the clinician's level of skills and experience. Of the studies described above, some of the treatments were provided by highly trained operators,17,19 while on other occasions, care was provided by postgraduate students. 21
Overall, the data suggest that direct composite restorations can be an effective medium- to long-term treatment option for managing tooth wear at both anterior and posterior teeth. The wearing away of direct composite, especially in the presence of mechanical wear may pose longer-term challenges, as discussed further below.
In conclusion, there are some important considerations to keep in mind when using direct composite, which can be summarized as follows:
Regular maintenance, including polishing, repair, and refurbishment, is likely to be necessary;
Molar restorations can be expected to survive, though they may require more frequent repairs;
Layer thickness is critical; restorations should be made as voluminous as possible while also respecting other parameters;
Sufficient operator skills and experience are likely to be essential for optimal outcomes;
Micro-filled resin composite materials should be avoided;
More severe levels of tooth wear are associated with a higher risk of failure;
In case of localized anterior wear, prescribing the Dahl approach may be recommended where the patient is deemed to be suitable;
The absence of posterior support may increase the risk of failure of anterior restorations;
Certain incisal relationships, such as Class II division 2, may elevate the risk of restoration failure, as might the nature of the antagonistic dentition.22
Patient perceptions of the treatment outcome using direct composite for the rehabilitation of tooth wear
How patients perceive the outcome of a treatment measure is also relevant and may be used to assess the quality of the care delivered from the patient's perspective. This must be given proper consideration. Significant improvements were reported in quality of life and in oro-facial appearance after 5 years of full-mouth rehabilitation using composite resin restorations.23
Improvements in the self-perception in the quality of speech function after full mouth occlusal rehabilitation for tooth wear using direct and indirect resin composite have also been reported.24
The performance of indirect restorations for the treatment of tooth wear
The use of direct resin composite offers a minimally invasive option, also providing patient satisfaction. However, patients should be aware of ongoing maintenance needs. Proper operator skills are also crucial.
Indirect restorations may offer superior occlusal and interproximal form, aesthetics, and durability, with a lower risk of fractures and chipping. Yet, they come with higher costs, and adjustments in the oral environment can be more challenging. Additionally, indirect restorations entail risks such as the need for tooth preparation and cementation breakdown.
The use of indirect composite resin restorations for the treatment of tooth wear
Indirect composite resin restorations can be fabricated using traditional methods, such as a die stone followed by a postcuring phase to enhance polymerization. Alternatively, they can be created from pre-polymerized resin blocks using CAD-CAM technology. Figure 2 is an example of a tooth wear patient, where rehabilitation has been provided using indirect composite resin restorations.
Figure 2.
(a) An example of a 47-year-old patient with localized anterior tooth wear owing to a combination of chemical and mechanical factors and a missing upper right first molar tooth. Treatment planning involved an increase in the VDO and restoration of both arches using additive means. (b) Initial post-treatment outcome. Lower anterior teeth were restored using direct composite. Upper anterior teeth were restored using indirect composite at the palatal surfaces and feldspathic porcelain at the labial surfaces. Maxillary posterior teeth were restored using additive overlays after the removal of previous silver amalgam restorations. (c) Follow-up at 13 years. This shows signs of wear of the upper anterior palatal veneers, lower anterior restorations, and some chippings at 3.7, 3.1 and 4.7. Signs of some marginal deterioration were also evident.
These restorations offer several advantages, including ease of adjustment, better control over occlusal contour and vertical dimension, and the potential for reduced chairside time compared to direct restorations. However, they generally require some tooth preparation, particularly for removing hard tissue undercuts, and are less durable than dental ceramics. Compared to ceramic materials they are also inferior in terms of flexural strength, abrasion resistance, fracture resistance, and discolouration rates.
Occlusal clearance levels for indirect posterior composite resin restorations can vary. Schlichting et al25 studied the performance of ultra-thin CAD-CAM indirect composite resin posterior occlusal veneers and provided occlusal clearance of 0.4–0.6 mm at the central groove area and 1.0–1.3 mm at the cusp tips.
Vialati et al26 demonstrated highly promising outcomes using a ‘sandwich approach’ for the restoration of severely worn anterior maxillary teeth with indirect composite veneers. Two groups of veneers, fabricated from different materials and with varying insertion paths, were found to effectively address wear without the need for invasive crown preparations. Among the indirect veneers evaluated, including 70 palatal indirect composite and 64 labial ceramic veneers, no significant or major failures were reported after approximately 50 months.
A 2021 study assessed the 3-year performance of direct and traditionally fabricated indirect hybrid composite restorations placed on the palatal surfaces of maxillary anterior teeth and the occlusal surfaces of first molars, known as ‘tabletop restorations.’27 Both direct and indirect restorations on maxillary anterior teeth showed good performance with AFRs below 2%. However, indirect molar tooth composite restorations exhibited a threetimes higher risk of failure compared to direct molar restorations with approximate AFRs of ±15% and ±5%, respectively, possibly owing to variations in layer thickness. The importance of sufficient layer thickness for the successful performance of (indirect) composite resin restorations could not be overstated.
In another study, the 5.5-year survival of 568 CAD-CAM manufactured indirect composite resin restorations (LAVA Ultimate, 3M) for the treatment of severe, generalized tooth wear was examined. Out of 96 reported failures, only six were catastrophic, with most involving minor issues like chipping and fractures. Overall survival and success rates were 99% and 83%, respectively. Direct molar tooth restorations showed a significantly higher risk of failure compared to indirect restorations.28
In conclusion, both direct and indirect composite resin restorations are viable options for treating tooth wear, offering comparably high success rates when appropriate materials and techniques are employed. CAD-CAM fabricated indirect composite resin restorations are likely to offer a better outlook, with restorations produced from homogeneous blocks. However, molar restorations may be at a higher risk of failure, underscoring the importance of proper technique and material selection to achieve optimal outcomes. Ensuring appropriate layer thickness of indirect composite resin restorations is critical.
Promising results have also been reported with the use of contemporary materials like polymer infiltrated ceramic network (PICN). These materials consist of a sintered ceramic matrix infiltrated with a polymer matrix, designed to closely mimic the mechanical properties of human enamel. PICN restorations can be milled to an extremely low thickness, as thin as 0.11 mm for molars (at the thinnest part of the restoration), allowing for easy intra-oral occlusal adjustments, including the addition of direct composite materials.
A prospective study of up to 5 years of 192 PICN CAD-CAM restorations reported impressive survival and success rates of 99.5% and 90.6%, respectively. The most common complication observed was minor chipping of the thin occlusal edges. Additionally, the mean wear of the material on occluding surfaces over the 5-year period was measured at 27.97 µm, which is comparable to the levels of physiological wear typically observed in natural teeth.29
Adhesively retained all-ceramic, partial coverage restorations for treating tooth wear often involve minimally invasive, additive occlusal veneers. Common materials used for these restorations include leucite-reinforced glass ceramics (e.g. IPS Empress, Ivoclar) and lithium disilicate-reinforced glass ceramics (e.g. IPS e.max, Ivoclar). Non-etchable ceramic materials, such as alumina or zirconia, can also be used owing to their superior strength and fracture resistance, though they lack the optical properties of their etchable counterparts.
For lithium disilicate onlays, such as IPS e.max, a minimum inter-occlusal clearance of 1.0 mm is required. Additionally, all internal line angles must be rounded, avoiding any grooves or sharp edges. The marginal finish should feature a circular shoulder with rounded internal line angles or a chamfer, and a convergence angle of approximately 10–30°, with a minimum inter-occlusal clearance of at least 1.0 mm.
Edelhoff et al30 reported a 100% survival rate for 274 minimally invasive lithium disilicate onlays used to treat tooth wear, with a total failure rate of 5.5% over a mean observation period of 8.5 ± 2.7 years, where the failures did not impact on restoration survival. In the same study, indirect posterior composite onlays also showed a 100% survival rate, but with a much higher total failure rate of 25.3% over a mean observation time of 6.7 ± 0.5 years. The composite restorations exhibited higher abrasion rates, increased material fracture, and more significant discolouration.
Two additional studies comparing lithium disilicate onlays with CAD-CAM manufactured indirect composite restorations also reported 100% survival rates for the ceramic restorations, with slightly lower survival rates for the polymer-based restorations.25,31 The polymer-based restorations, however, showed higher wear rates, signs of chipping, and significant differences in surface roughness, including evidence of surface degradation.
Based on the available evidence, partial coverage, adhesively retained ceramic restorations are more likely to offer a stable, long-term occlusion with optimal form and aesthetics, and lower maintenance needs, especially at molar teeth, compared to indirect composite resin. However, ceramic occlusal onlays typically require more invasive tooth preparation than directly bonded resin composites or possibly even indirect composite onlays. Nevertheless, composite-based restorations (both direct and indirect) offer the advantage of easier repair in the oral environment and should be the preferred initial treatment choice.8
Figure 3 illustrates the use of adhesive ceramic materials for the restoration of tooth wear.
Figure 3.
(a) Example of a 37-year-old patient with tooth wear, primarily a result of a chemically related aetiology. A minimally invasive adhesive approach was adopted, using ultra-thin ceramic restorations. (b) Monolithic lithium disilicate final restorations. Lower anterior teeth (labial veneers). Upper anterior (‘V’ veneers). Upper and lower posterior were restored using occlusal overlays.
Full coverage tooth-coloured crowns
Treatment options for tooth wear can include the use of conventionally retained crowns, which rely on mechanical preparation to provide retention and resistance, or adhesively retained crowns, which also benefit from the chemical adhesion of the cementation material. Full coverage crowns may be recommended in cases where predictable bonding is challenging, when multiple existing or failed crown restorations are present, or when patients are concerned about the maintenance requirements of direct resin composite restorations. However, no restoration type can offer a guaranteed longer term outcome.
While porcelain-fused-to-metal (PFM) crowns have a long history of use, there is a lack of high-quality evidence supporting their effectiveness for treating tooth wear. Additionally, there is no clear evidence suggesting that conventional crown restorations require less maintenance than alternative treatments for the management of the worn dentition.
Smales and Berekally compared the 10-year survival rates of direct and indirect restorations for advanced tooth wear, reporting survival estimates of 59% for directly bonded anterior resin composite restorations and 70% for indirect anterior metal-ceramic crowns. The most common failure mode for direct resin composites was restoration fracture, which could often be repaired or replaced. In contrast, crown failures were typically catastrophic, often leading to complete restoration loss and requiring endodontic treatment or even extraction.32 With younger patients increasingly presenting with severe tooth wear, contingency planning is crucial when determining treatment strategies.
Burke reported favourable 4-year outcomes for dentine-bonded all-ceramic crowns in a prospective study involving 59 crowns, primarily placed in patients with tooth wear at anterior and premolar sites. The study found a very low incidence of fractures, excellent retention, and an overall failure rate of just 6%.33
All-ceramic, full coverage adhesively bonded restorations can also be applied using a traditional, subtractive approach. Milosevic and Burnside examined the 7-year survival of 161 zirconia-based crowns (Lava) used to manage severe anterior tooth wear. The study observed a relatively low overall failure rate of 15.5%, with failures typically owing to de-bonding or minor delamination within the ceramic layer. An edge-to-edge incisor relationship and a predisposition to tooth wear from attrition or bruxism were associated with higher failure risks.34
More recently, a further study reported long-term success in a randomized clinical trial with up to 6 years of observation, evaluating 361 pressed lithium disilicate crowns and 351 translucent zirconia crowns for extensive tooth wear. Both types of crowns, applied to anterior and posterior teeth and adhesively luted with resin-based cement, showed success rates exceeding 98%. However, the aesthetic outcomes of the translucent zirconia crowns were rated lower than those of lithium disilicate crowns by a blinded clinician.35
While full coverage crown restorations offer a predictable, lower-maintenance, medium-term solution for worn teeth, it is essential to carefully discuss the associated risks, including the well-known biological complications such as significant coronal volume loss and the potential for irreversible pulp tissue damage. For metal-ceramic crowns, minimizing the ceramic extension may help achieve a more conservative restoration.
Conclusion: navigation by numbers
Systematic reviews have not provided clear evidence favouring any dental material or treatment technique for the restoration of tooth wear. Direct composite restorations offer the advantage of minimally invasive procedures and allow the clinician to verify planned changes, but they can be demanding to execute. CAD-CAM fabricated indirect composite restorations also present a predictable medium-term conservative treatment option, especially when superior anatomical form is desired or when direct bonding may be challenging. However, some tooth preparation is often required. Molar restorations, whether direct or indirect, generally demand higher maintenance, with expected issues such as loss of lustre, chipping, and staining.
Composite materials, both direct and indirect are also prone to wear,36 which can be problematic in high-risk cases, such as severe bruxism. This wear may lead to occlusal instability, which may have negative consequences. Consequently, these patients require vigilant monitoring and maintenance, and it is crucial to inform them of this need from the outset.
Ceramic materials, whether used for partial or full coverage restorations, tend to offer better long-term survival, with superior wear resistance, aesthetic stability, and occlusal stability. However, ceramic restorations are more expensive, typically more invasive than direct composites, and are less amenable to intra-oral adjustments, which is a significant drawback. Using direct composite as the first line of treatment allows for the verification of the patient's acceptance and tolerance of planned changes in a minimally invasive manner. Once these changes are established, if needed, the functional and aesthetic outcomes can be replicated and enhanced by replacing existing composite restorations with adhesively retained ceramic restorations, (or alloys) which have been shown to offer very high survival rates and superior wear and aesthetic stability.
Full coverage crowns do have a role in treating tooth wear, but obtaining informed consent is critical, and meticulous clinical techniques must be applied. In the author's opinion, the primary focus of restorative interventions should be the preservation of tooth structure, with the survival of the restoration being a secondary concern.
