Neo JCL, Yap AUJ. Composite resins. In: Mount GJ, Hume WR (eds). Queensland: Knowledge Books and Software; 2005
Sarrett DC. Clinical challenges and the relevance of materials testing for posterior composite restorations. Dent Mater. 2005; 21:9-20
Mjör IA. Repair versus replacement of failed restorations. Int Dent J. 1993; 43:466-472
Wilson NHF, Setcos JC, Brunton PA. Repair versus replacement of restorations. In: Wilson NHF, Roulet JF, Fuzzi M (eds). Chicago: Quintessence Publishing Company; 2001
Frankenberger R, Roth S, Krämer N, Pelka M, Petschelt A. Effect of preparation mode on Class II resin composite repair. J Oral Rehabil. 2003; 30:559-564
Anusavice KJ. Conference report: criteria for placement and replacement of dental restorations. J Dent Res. 1988; 67:795-796
Blum IR. The management of failing direct composite restorations: replace or repair?. In: Lynch CD, Brunton PA, Wilson NHF (eds). London: Quintessence Publishing Company; 2008
Mjör IA. Clinical diagnosis of recurrent caries. J Am Dent Assoc. 2005; 136:1426-1433
Christensen GJ. When and how to repair a failing restoration. J Am Dent Assoc. 2007; 138:1605-1607
Mjör IA, Toffenetti F. Secondary caries: a literature review with case reports. Quintessence Int. 2000; 31:165-179
Denehy G, Bouschlicher M, Vargas M. Intraoral repair of cosmetic restorations. Dent Clin North Am. 1998; 42:719-737
Özcan M, Barbosa SH, Melo RM, Galhano GA, Bottino MA. Effect of surface conditioning methods on the microtensile bond strength of resin composite to composite after aging conditions. Dent Mater. 2007; 23:1276-1282
Passos SP, Özcan M, Vanderlei AD, Leite FP, Kimpara ET, Bottino MA. Bond strength durability of direct and indirect composite systems following surface conditioning for repair. J Adhes Dent. 2007; 9:443-447
Rodrigues SA, Ferracane JL, Della Bona A. Influence of surface treatments on the bond strength of repaired resin composite restorative materials. Dent Mater. 2009; 25:442-451
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Defective dental restorations: to repair or not to repair? part 1: direct composite restorations Igor R Blum Daryll C Jagger Nairn H F Wilson Dental Update 2024 38:2, 707-709.
Clinical Lecturer/Hon Specialist Registrar in Restorative Dentistry, University of Bristol Dental Hospital & School at Guy's, King's College and St Thomas' Hospitals, London, UK
Professor of Restorative Dentistry and Dean and Head of King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, London, UK
The presentation of patients with failing dental restorations that exhibit minor defects is a common clinical situation in everyday dental practice. The repair of such restorations, rather than replacement, is increasingly considered to be a viable alternative to the replacement of the defective restoration. This first of two papers considers indications and techniques for the repair of defective direct composite restorations.
It is possible that some dental practitioners are unaware of the option of repair rather than replacement of composite restorations. This article provides an overview of contemporary knowledge and understanding of restoration repair in the clinical management of defective composite restorations.
Clinical Relevance: A sound understanding of the indications, benefits and techniques of direct composite restoration repair could allow the longevity of the existing restoration to be extended without unnecessarily sacrificing healthy tooth structure.
Article
There is clearly an increasing demand for aesthetic dental restorations from the general public and dentists are spoilt for choice as to which materials to use and how best to use them. There is no disputing the excellent aesthetics that can be achieved with composite resin as a restorative material; however, the longevity of these materials can be disappointing, especially if not placed using a careful incremental technique.1 With the increasing use of these materials for the restoration of large defects in posterior teeth, these materials are tested to the maximum.
The management of composite restorations with localized defects is a common challenge in clinical practice. While some restorations will inevitably require replacement, it has been suggested that some deteriorating, yet serviceable, restorations may be given extended longevity through the use of repair procedures.2 This comparatively more conservative approach to the management of defective restorations, if appropriate, has the potential to be less costly in terms of time and financial resources, less traumatic for patients, less likely to result in iatrogenic damage, possibly obviate the need for the use of local anaesthesia and be more conservative of tooth tissue.3–5 It is clearly preferable, therefore, to perform a restoration repair (ie partial replacement of the composite restoration allowing preservation of that portion of the composite restoration which presents no clinical or radiographic evidence of failure) as an alternative to restoration replacement (removal of an entire composite restoration followed by the placement of a new composite restoration) wherever possible. It is accepted that removal of part of the restoration without the aid of magnification loupes can further result in removal of sound tissue and subsequent increase in the size of the cavity.
It has been suggested that repair procedures may be most effective when they correct placement defects in otherwise high quality restorations.6 This is possible given that a placement defect, for example chipping of a margin on finishing, or early signs of deterioration in clinical service, tend to be limited to a small part of the restoration, typically a short section of the cavosurface margin. The repair of a composite restoration may include an element of refurbishment – a procedure that should normally pre-empt and delay repair, let alone replacement. Refurbishment procedures typically involve the refinishing or resurfacing of a restoration, with or without recontouring.3 Refinishing may be limited to the margins of a restoration, while resurfacing may involve part or all of the exposed surfaces of the restoration.
Rationale for restoration repair
The main reasons reported3,7 for the repair, rather than the replacement, of defective direct composite restorations include:
Preservation of tooth structure;
Increased longevity of the restoration;
Reduction of potentially harmful effects on the dental pulp;
Reduction in treatment time;
Reduced cost to the patient;
Good patient acceptance;
No need for local anaesthesia, provided the repair is not extensive;
Less risk of iatrogenic damage to adjacent teeth.
Criteria for repair of restorations
The criteria which play a role in the choice of repair as opposed to the replacement of defective restorations include patient-centred and tooth-specific criteria.
Patient-centred criteria
Dentally motivated patients who attend on a regular basis, and maintain a good standard of oral health, have been deemed good candidates for restoration repair procedures.7 Patients who have complex medical histories or limited capacity to co-operate may also be viewed as suitable candidates for the repair rather than the replacement of failing restorations, in particular if operating time needs to be kept to a minimum. Repair procedures can often be accomplished without the need for local anaesthesia and complex operative procedures. It has also been suggested that, in situations in which there is a risk of inappropriately extending the operating time, and possibly causing distress to the patient, it may be sensible to complete an effective repair rather than attempt a replacement restoration.4 It is appreciated however that, under these circumstances, the replacement restoration may be considered to be more of a ‘patch and make good’ than a good quality repair.
In planning to undertake a repair of a restoration, it is important that the patient is fully informed of the advantages and possible limitations of the repair procedure and how this procedure differs from replacement of the restoration. In obtaining informed consent for a restoration repair procedure, the patient must understand that he/she will not be receiving a new restoration and that a repair may be subject to early failure, given that a repair may not correct a fundamental flaw in the design of a restoration.4
Tooth-specific criteria
Tooth-specific criteria for the repair of direct composite restorations include:
Localized marginal defects and marginal staining;
Bulk fracture of a limited portion of the restoration;
Secondary caries, as diagnosed clinically;
Colour correction;
Localized wear of the restoration;
Fracture of adjacent tooth tissue.
Localized marginal defects and marginal staining
The presence of limited marginal defects does not necessarily indicate the presence or likelihood of secondary caries.8 Many marginal defects in direct composite resin restorations can be simply managed using refurbishing procedures (Figures 1 and 2), given that the overcontouring associated with many direct composites results in chipping and in marginal overhangs. Such overhanging margins may be removed using a fine-grit diamond finishing bur. This will also remove any superficial staining which may have accumulated in the angle of the overhang and help harmonize the contour of the restoration and the adjacent tooth surface. Great care must, however, be taken not to damage the adjacent enamel surface iatrogenically. The composite resin surface is subsequently polished using appropriate composite finishing systems, possibly followed by the application and photopolymerization of an unfilled resin which may seal over any marginal cracking of the composite and enamel and provide a surface glaze which will, in all probability, wear away relatively rapidly in clinical service.
Figure 1. Stained margins visible around composite restorations.Figure 2. Removal of stained margins by refinishing and polishing of restoration (=refurbishment).
Minor marginal defects on the occlusal surfaces of posterior composite restorations, which are imperceptible to the patient, are usually best monitored, with intervention being delayed until there is evidence of plaque accumulation or food stagnation, with associated discoloration, which may result in secondary caries.6 Marginal defects in anterior composite restorations are more problematic because of their tendency to pick up exogenous stain, in particular, in smokers and individuals who consume large amounts of, for example, black coffee. Refinishing coupled, where necessary, with refurbishment of the restoration is typically the most effective way to manage such staining successfully. However, if a heavy, interface penetrating stain is present, then the restoration may not be amenable to repair procedures and total restoration replacement will then be necessary to obtain a high quality aesthetic outcome. In such situations, careful bevelling of cavity margins and meticulous finishing of the replacement restoration may minimize the risk of early recurrence of the problem. In cases in which staining is heavy and returns quickly following corrective procedures, and in situations in which the anterior teeth are heavily restored, the patient should be encouraged to at least reduce or discontinue the habit or consumption of whatever is considered to cause the staining.
Bulk fracture
When a patient presents with a bulk fracture of a composite resin restoration, in particular, soon after restoration placement, it is important to diagnose and eliminate the reason for the fracture; for example, excess occlusal loading or inappropriate or excessive use of a liner or base, resulting in the restoration lacking support or thickness sufficient to withstand normal loading. Diagnosis and correction of the underlying problem is necessary to avoid recurring bulk fracture, or a fracture involving remaining tooth tissue. Bulk fracture of a composite restoration that has been in clinical service for many years is likely to be the result of stress fatigue within the composite material. If the bulk fracture is limited (up to half of the restoration) and the restoration is months rather than years old, repair may be indicated; however, the integrity of the remaining portion of the restoration should be carefully assessed clinically and possibly radiographically. Repair of a bulk fracture, for example, loss of an incisal corner of a large incisal proximal composite, is to be favoured over total restoration placement, in particular when the repair will avoid disturbing a successfully treated pulp exposure.9
Secondary caries
Caries adjacent to the margin of a composite restoration (secondary caries) should be treated as a new primary lesion.10 As with all patients who present with a new lesion, preventive measures should be initiated, followed by operative intervention as, and when, the lesion is shown to be active and progressing through dentine, or cavitation has occurred. Operative intervention should be minimally interventive, coupled with partial replacement of that portion of the adjacent composite restoration which is undermined by caries, or hinders the access required for necessary caries removal and the placement of an effective repair (Figures 3 and 4). The portion of the composite restoration which presents no clinical or radiographic evidence of failure should be left in place, unless there is good clinical indication to resort to total restoration replacement with its various consequences. With a tendency to practise ‘defensive dentistry’ in a society which is increasingly litigious, it is regrettable that restorations affected by early forms of secondary caries, which are amenable to repair, may continue to be managed by total replacement.
Figure 3. Clinical appearance of first premolar with removed distal portion of three surface composite restorations due to secondary caries at the distal floor.Figure 4. Restoration following repair procedure.
If there is good reason to suspect that leakage has occurred along the tooth/restoration interface of the part of the restoration unaffected by the lesion of secondary caries, then total replacement should be undertaken. Similarly, if it is anticipated to be difficult to achieve a good marginal seal to a repair, which would prevent the progress of any residual caries, then total replacement may be indicated.
Superficial colour correction
On occasions, an incorrect shade may have been selected for a previously placed composite restoration. If the mismatch in shade is limited, this may be managed by resurfacing the restoration using a different shade of composite material. Wherever possible, the same restorative material should be used as the composite substrate, but this might not be possible if the restoration was placed by a different practitioner, details of the material used were not recorded in the patient's notes, or the previously placed material is no longer commercially available. Success in such colour correction procedures requires an understanding of the optical properties of restorations and remaining tooth tissues and the effects of layering different shades of composites. In certain situations, for example, where a relatively light, translucent shade of composite has been used on its own to restore a large ‘through-and-through’ anterior proximal restoration, total replacement may be the only solution to achieving a good aesthetic outcome. This assumes that there would be some contra-indication to attempting to resolve the situation by means of a palatal access colour correction using, in all probability, a dentine shade of the relevant composite. In many situations, a colour correction can be attempted before taking the decision to resort to a total restoration replacement procedure.
Wear of the restoration
As wear of composite resin restorations may have been accompanied by passive eruption, or tilting of opposing and adjacent tooth or teeth, the situation needs to be assessed carefully. If the wear of the restoration is of a limited nature, for example, shallow faceting confined to a section of the occlusal surface, and space exists to perform a repair, then the situation may be resolved by resurfacing the restoration. This is possible typically where the wear has been caused by three-body abrasion during chewing rather than by, for example, a parafunctional attrition. If the wear involves a proximal surface and no space exists to restore anatomic form, then an alternative restorative approach may be indicated.
While developments in the physical qualities of dental composite resins have largely overcome problems of functional wear in composite restorations under normal loading conditions, it remains prudent to adopt operative techniques which maintain enamel-to-enamel contacts between opposing teeth. Such contacts should be identified pre-operatively using articulating paper and then preserved by careful planning of the outline of the preparation.11
Fracture of adjacent tooth tissue
Fracture of tooth tissue adjacent to a composite resin restoration may occur for various reasons, including:
Inappropriate location of loading;
Bearing occlusal contacts;
Insufficient or unsupported tooth tissue;
Parafunctional activity;
Trauma; or
Subsequent to damaging polymerization stresses at the time of restoration placement.
A repair may be indicated if the cause of the fracture can be diagnosed and, as a consequence, the risk of further fracture minimized by redesigning the restoration to improve the biomechanical properties of the restored tooth unit. In this process, a key consideration is the design of the occlusal morphology. Wherever possible, occlusal contacts should be left in a central location to ensure that functional loading will be predominantly axial rather than lateral in nature.12
Contra-indications for repair
Repairs are not without contra-indications. In many cases, the contra-indications are multifactorial, with two or more negative features collectively making a repair an unattractive, relatively high risk option. Specific contra-indications include:
Patient reluctance to accept a repair as an alternative to restoration replacement;
Irregular attenders;
High caries risk patients;
Presence of caries undermining the restoration;
History of failure of a previous repair.
In addition, repairs should not be contemplated if there is uncertainty as to the type of material from which the restoration is formed, or as to the procedure to be followed to ensure a satisfactory clinical outcome.
Clinical procedure for composite restoration repair
As previously reinforced, before undertaking treatment which includes the repair of one or more restorations, it is important that the limitations and possible consequences of the proposed repairs are explained to the patient as part of the consent procedure.
Two repair methods are now described, one using an air–abrasion technique based on silica-coating and one for using a conventional adhesive bonding system.
The following steps apply equally to both techniques:
Administer local analgesia, as indicated clinically.
Clean the tooth or teeth to be repaired, together with the adjacent teeth, using pumice.
Remove the defective part of the composite restoration and any adjacent lesions of secondary caries.
Ensure adequate moisture control (rubber dam isolation).
Pulp protection, if indicated, according to contemporary regimes.
Bevel the margins of the preparation, as indicated clinically, and place a long (1.0 mm wide) deep bevel on the margin of the composite resin to be repaired. Appropriately prepared bevels increase the available surface area for bonding and facilitate a more aesthetic clinical outcome, as the composite resin to be used for the repair will blend in more effectively with the existing composite resin and remaining tooth tissues.
Method 1: Composite repair based on sandblasting with silica-coated particles
This technique involves blasting the composite substrate surface using the CoJet surface treatment system (CoJet System, 3M ESPE, Germany). This system includes the CoJet Prep Particle Micro-blaster, CoJet Sand, with a mean particle size of 30 μm, a silane (3M ESPE – SIL) and the corresponding unfilled resin adhesive (Visio Bond, 3M ESPE). This system is based on the working principle that it increases the bond strength of the repair composite resin to the composite resin substrate owing to an increase in silica content of the substrate surface; thereby rendering the substrate chemically more reactive to resin, via a silane coupling agent which provides a chemical basis for enhanced resin bonding. The ensuing clinical steps are as follows:
Sandblast the composite resin substrate surface and, if present, any exposed adjacent tooth tissue using the CoJet micro-blaster, according to the manufacturer's directions for use. The blasting pressure results in embedding of CoJet silica particles in the substrate surface to a depth of up to 30 μm. This increases the surface area available for bonding and facilitates micromechanical retention. After a brief (approximately 5 seconds) blasting of the silica particles, excess powder is dispersed using a three-in-one syringe. It is important that any powder on the margins of the remaining tooth tissues is removed. It is imperative that sandblasting takes place under rubber dam isolation.
The silica-coated composite substrate surface is silanized by the application of the silane, according to the manufacturer's directions for use. The silane acts as a bifunctional molecule which chemically binds to the silica-coated composite substrate.
The corresponding adhesive is then applied to the silanated composite substrate and a conventional adhesive bonding system to the adjacent tooth tissue, if present, according to the manufacturer's directions for use.
Following the placement of matrices and wedges, as indicated clinically, a composite resin material is applied using an incremental technique to repair the defect. Each increment must be polymerized using a visible light-curing unit. Ideally, the same type and brand of composite resin material should be used for the repair as the composite resin substrate, provided this information is known to the dental practitioner. The composite resin substrate must be at least 2 mm thick for the repair procedure to be successful. If circumstances dictate that the required matrix is placed prior to sandblasting, it may prove necessary to replace the matrix subsequent to the sandblasting, if particles of sand accumulate and resist removal interproxmally.
The rubber dam is then removed.
The repair is then carefully contoured and finished using contemporary composite finishing systems, to leave the repair integrated imperceptibly into the restored tooth unit.
The occlusion is then checked to ensure that the repaired restoration will not be subjected to adverse occlusal loading.
Method 2: Composite repair based on conventional adhesive bonding systems
This technique should be performed under rubber dam or with the judicious use of cotton wool rolls, salivary ejectors and other means to ensure moisture isolation. The clinical steps are as follows:
Acid etch the composite resin substrate together with the adjacent tooth tissue preparation margins for 15–30 seconds and wash thoroughly and dry the area using a three-in-one syringe. In addition to producing a favourable substrate surface for bonding, acid etching has a favourable cleansing effect.
An adhesive bonding system should be applied to the acid-etched composite substrate and adjacent tooth tissues and preparation margins, according to the manufacturer's directions for use. Alternatively, a commercially available composite repair system (eg Ecusit-Composite Repair, DMG, Germany; Clearfil Repair Kit, Kuraray, Japan), which includes its own specifically formulated adhesive agent, may be used.
A composite resin restorative material, compatible with the adhesive bonding system, is applied using an incremental technique to repair the defect, with each increment being fully photo-polymerized. Again, the same type and brand of composite material should be used as the composite substrate, provided this information is known to the practitioner.
The repair is then carefully contoured and finished using contemporary composite finishing systems, which allows the repair to be integrated imperceptibly into the restored tooth unit.
The occlusion is then checked to ensure that the repaired restoration will not be subjected to adverse occlusal loading.
Which repair system?
While some in vitro studies report higher repair bond strengths using the CoJet system,13–15 Padipatvuthikul and Mair16 showed in vitro that the application of a dentine bonding agent, even without mechanical treatment of the original composite surface, significantly enhanced the repair bond strength. Thus, the data available to date remain relatively limited. More importantly, long-term in service data on the clinical performance of different types of surface conditioning methods for composite resin repair remain to be generated. As in all bonding procedures, attention to detail, strict compliance with manufacturer's directions for use and careful operative technique, based on knowledge and understanding of the materials being used, is as important, if not more important, than the selection of the material from the range of products available from reputable manufacturers.
Concluding comments
The decision to repair rather than replace a defective or failing restoration is multifactorial. While much remains to be investigated in respect of the repair of restorations, it is likely that the replacement of restorations will continue to be a common procedure in the everyday clinical practice of dentistry for many years to come. Repair, as opposed to replacement, of restorations aids the preservation of natural tooth tissue, which is desirable. Thus, wherever possible, repair rather than replacement should be undertaken. However, repair of a restoration can be clinically and technically demanding and restorations will fail if not carried out with appropriate skill and understanding of the materials and procedures involved.
