REPAIR VERSUS REPLACEMENT OF DEFECTIVE DIRECT DENTAL RESTORATIONS IN POSTERIOR TEETH OF ADULTS IGOR R BLUM1, CHRISTOPHER D LYNCH2

Introduction Direct restorations, in common with all restorations, suffer deterioration (“wear and tear”) in clinical service. The presence of defective restorations or restorations with the clinical diagnosis of secondary caries is one of the most frequent situations encountered by general practitioners. The replacement of restorations constitutes around half of the work performed by general dental practitioners in their practices.1 However, this approach may be regarded as over-treatment, since in most cases large portions of the restorations may clinically and radiographically be considered free of failures.2 Furthermore, restoration replacement invariably results in the acceleration of the ‘restoration cycle,’3 with weakening of the tooth through the unnecessary removal of intact tooth structure in locations often distant from the site of restoration deterioration, and the potential for repeated insults to the pulp. Consequently, the diagnostic finding of an existing restoration as defective is a critical step in treatment planning, and it invariably affects the longevity of the restoration and the restored tooth.

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Igor R Blum

Consultant/Hon.Senior Lecturer in Restorative Dentistry, King’s College Hospital Dental Institute, London, UK 2

Christopher D Lynch

Reader/consultant in Restorative Dentistry, School of Dentistry, Cardiff University

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The diagnosis of secondary caries is inconsistent among dental practitioners, and often does not rely on objective criteria.4-7 If in doubt, most general dental practitioners choose replacement as opposed to options of non-operative treatment, including systematic restoration monitoring. Restoration replacement is especially common for restorations not originally placed by the evaluating practitioner.8 A dental practice-based research study involving 197 clinicians from the USA and Scandinavian countries, and close to 10,000 restorations, indicated that practitioners chose replacement over repair of restorations with localised defects in over 75% of cases.9 The same

study confirmed that practitioners who did not place the original restoration were more likely to replace it than practitioners who did. Although the criteria for the diagnosis of a defective restoration may be based solely on visual and tactile examination, the subsequent management plan for this restored tooth should also be based on the caries risk assessment of the patient. Most restoration defects occur gradually, but abrupt defects – such as bulk fractures – also can occur.9 The recognition of defects does not necessarily coincide with the failure of a restoration to the extent that it requires immediate replacement. Defects can develop gradually, a situation that may provide the clinician with an opportunity to perform minimally invasive treatment rather than replacing the entire restoration. This minimally invasive treatment may include repairing or refurbishing a defect,10-12 especially if the defect is localised and accessible.

Teaching Between 2002 and 2012, seven surveys were published on the teaching of the repair of resin-based composite (RBC) restorations in various countries (UK, Ireland, Germany, Scandinavia, USA, Canada),2,11-16 as well as one paper on dental restorative material manufacturers’ opinions.17 Owing to the increasing trend at dental schools in numerous countries in favour of the placement of RBC over amalgam restorations,18-22 all surveys focus on direct RBC restorations. Teaching of repair is now included in most dental schools in Europe and North America. In 2010/2011, 15 of 17 dental schools (88%) in the UK and Ireland included repair techniques for defective RBC restorations in their

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curricula.16 In the same year, 42 of 48 responding schools (88%) in USA and Canada taught repair of defective composite fillings in their curricula, whereas 79% of these schools provided didactic as well as clinical teaching.23 Eleven of 12 Scandinavian dental schools (92%) responded in 2010/2011 that they included teaching of composite repair techniques.15 In 2009/2010 in Germany, 24 of 25 dental schools (96%) performed repairs in their clinical practice and 88% (22/25) included repair in teaching, while two additional dental schools were planning to introduce it in the next years.14 This was a remarkable increase in comparison to 2000/2001, when only 50% of the responding dental schools in Germany had included repair in their teaching and 33% had not planned to introduce it in the following five years.12 Nearly all of the dental schools consider repair as an option of minimally invasive treatment, thereby stopping or retarding the restorative downward spiral, with endodontic treatment and tooth extraction at the end.

Criteria for decision-making The terms glazing, sealing, refurbishment or repair are often used interchangeably in the literature but they do not have the same meaning. Setcos et al 24 published four clear structured terms and indications that were redefined by publishing the FDI criteria.25 There are in general four options for managing defective restorations:26 1 No treatment (monitoring): if only minor shortcomings (eg. unfavorable colour/staining or suboptimal margins) are present, with no clinical disadvantages if untreated. 2 Refurbishment: can be done if shortcomings are adjustable without damage to the tooth, eg. removal of overhangs, recontouring the surface, removal of discoloration, smoothening or glazing of surface including sealing of pores and small gaps, which can be improved without adding new restorative material (except glaze or bonding).

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3 Repair: is indicated mainly in case of localised shortcomings, which are clinically unsatisfactory and no longer acceptable. Repair is a minimally invasive approach that implies in any case the addition of a restorative material (not only glaze or adhesive), with or without a preparation in the restoration and/or tooth structure.25,27 4 Replacement: is indicated if generalised or severe problems make intervention necessary, and a repair is not reasonable or feasible. Replacement is the complete removal of the restoration, usually combined with significantly more loss of tooth structure. Replacement is an often unnecessarily costly treatment, which sacrifices sound tooth tissue (often distant from the site of restoration deterioration), reduces the likelihood of continuing pulp vitality, results in larger restorations and increases the risk of pulpal disease and accelerated tooth loss. In comparison, the advantages for repair are summarised as follows:28-29 1 Less loss and more preservation of tooth structure 2 Reduction of potentially harmful effects on the dental pulp 3 No need for local anaesthesia, provided the repair is not extensive 4 Often less risk of iatrogenic damage to adjacent teeth 5 Reduction of treatment time 6 Reduced costs to the patient 7 Good patient acceptance 8 Increased longevity of the restoration. Whilst some restorations will inevitably require replacement, it is suggested that many deteriorating, yet serviceable, restorations may be given extended longevity through refurbishment or repair procedures, provided that the repaired restoration satisfies the necessary clinical requirements.30 This is most encouraging for those minded to adopt, and possibly teach, minimal intervention techniques for the lifelong management of restored teeth. In addition, repair procedures may

be less distressing for a patient when compared with replacement.28,31 Criteria for repair Many criteria play a role in the selection of repair as an alternative to the replacement of direct composite restorations with localised defects. These include the patient’s caries risk status, the clinical condition of the restored tooth unit and cost/benefit assessments. Criteria for repair, as opposed to complete restoration replacement, can be broadly divided into two categories: patient-centred and tooth-specific criteria. Patient-centred criteria Dentally motivated and informed patients who attend on a regular basis, maintain a good standard of oral health, and in whom the restorations can be monitored regularly are good candidates for composite repair procedures. Another group of suitable candidates for repair procedures comprises patients who have complex medical histories or limited capacity to cooperate. In such patients, the nature of the intervention should be limited in terms of time and complexity. Refurbishment procedures can often be accomplished without the need for local anaesthesia and are therefore especially advantageous for patients with complex medical histories. It is important that patients understand the nature of the repair procedure and how this procedure differs from restoration replacement. In obtaining informed consent for a composite repair procedure, it is essential to outline the disadvantages of the replacement strategy in terms of its effect on the longevity of the restored tooth unit. Similarly, the advantages of the repair strategy in terms of preserving tooth structure and its minimally interventive nature must be elicited. In deciding whether to repair or replace a composite restoration in the presence of secondary caries, as diagnosed clinically, the decision to repair rather than replace is more likely to be correct in a patient

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with a low risk of caries. If the decision is made to replace the restoration in such a patient, the preparation will be enlarged unnecessarily and the tooth inappropriately weakened. The longevity of the replacement restoration may suffer uncertainties, as well as the increased risk of more complex and costly subsequent treatment, including endodontic therapy. Notwithstanding these shortcomings, the replacement restoration may be subjected to the same (possibly unrecognised) limitations of the original restoration. Tooth-specific criteria Having ascertained that patient-centred criteria are satisfied, tooth-specific criteria must be considered. To assess tooth-specific criteria, it is important to employ an appropriate selection of investigative techniques – no one investigative technique alone is sufficient to provide all the necessary information. Magnification aides for visual inspection and the interpretation of radiographic images are considered invaluable in maximising the sensitivity and specificity of clinical assessments.

Clinical indications for RBC restoration repair Secondary caries Caries (secondary) adjacent to the margin of a composite restoration should be treated as a new primary lesion. As with all patients who present with a new lesion, preventive measures should be initiated, followed by operative intervention if 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 that is undermined by the caries or hinders the access required for effective caries removal. The portion of the composite restoration that presents no clinical or radiographic evidence of failure should be left in place, unless there is a good clinical indication to resort to total restoration replacement, with its various consequences. Marginal defects and marginal staining It is important to realise that the presence of marginal defects does not always indicate the presence of secondary caries. If limited, marginal defects can be simply managed using refinishing procedures. Minor marginal defects in the occlusal surfaces of posterior composite restorations which are imperceptible to the patient are best monitored, with intervention being delayed until there is evidence of plaque accumulation, food stagnation or discoloration which may herald active caries. Marginal defects in anterior composite restorations are more problematic because of their tendency to pick up exogenous stain. Refinishing, coupled with refurbishment of the restoration where necessary, is typically the most effective way to manage such staining successfully. If heavy penetrating staining is present, total restoration replacement may be required to obtain a high-quality aesthetic outcome. Superficial colour correction If an incorrect shade has been selected for a previously placed composite restoration, this may be managed by

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resurfacing 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. Wear of the restoration As wear of a composite restoration may have been accompanied by passive eruption, or at least tilting of the opposing tooth or teeth, the situation needs to be assessed most carefully. If the wear of the restoration is of a limited nature and confined to the occlusal surface, and space exists to effect a repair, then the situation may be resolved by resurfacing the restoration. If the wear involves a proximal surface and no space exists to restore the anatomic form of the restoration, then an alternative restorative approach may be indicated.

Clinical indications for RBC and amalgam restoration repair Bulk fracture When a patient presents with a bulk fracture of a restoration, particularly soon after restoration placement, it is important to diagnose and eliminate the reason for the fracture; for example, excess occlusal loading. This is necessary to avoid recurring bulk fracture, or indeed a fracture including remaining tooth tissue. Bulk fracture of a restoration that has been in clinical service for many years is likely to be the result of stress fatigue within the restorative material. If the bulk fracture is limited (less than half of the restoration), repair may be indicated; however, the integrity of the remaining portion of the restoration should be carefully assessed. Fracture of adjacent tooth issue Fracture of tooth tissue adjacent to a restoration may occur for various reasons, including parafunctional activity or trauma, or may be subsequent to

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The CoJet-Sand sandblaster

damaging polymerisation stresses at the time of restoration placement. A repair may be indicated if the cause of the fracture can be accurately diagnosed and, as a consequence, the risk of further fracture minimised, possibly through a preventive measure such as the provision of a mouthguard for a bruxist patient. Contraindications for repair These include: • patient reluctance to accept a repair as an alternative to restoration replacement • irregular attenders • patients at high risk of caries

REFERENCES 1

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Mjör IA, Shen C, Eliasson ST, Richter S. Placement and replacement of restorations in general dental practice in Iceland. Oper Dent 2002;27:117–123. Gordan VV, Mjör IA, Blum I, Wilson NHF. Teaching students the repair of resin based composite restorations: A survey of North American dental schools. J Am Dent Assoc 2003;134:317–323. Elderton R. Principles in the management and treatment of dental caries. In: Elderton R, editor. The dentition and dental care. Oxford: Heinemann

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• presence of caries undermining most of the existing restoration • history of failure of a previous repair.

Repair procedures From the published in vitro data at present, the following recommendations for repair can be made:32-33 Clinical procedure The clinical procedure for the repair of a failing direct RBC restoration is as follows: • Give local analgesia, as indicated clinically. • Remove the defective part of the composite restoration and any adjacent secondary caries.

Medical Books; 1990. p. 237262. Kay E, Watts A, Paterson R, Blinkhorn A. Preliminary investigation into the validity of dentists’ decisions to restore occlusal surfaces of permanent teeth. Community Dent Oral Epidemiol 1988;16:91–94. Noar SJ, Smith BGN. Diagnosis of caries and treatment decisions in approximal surfaces of posterior teeth in vitro. J Oral Rehabil 1990;17:209–218. Bader JD, Shugars DA. Agreement among dentists’ recommendations for restorative treatment. J Dent Res 1993;72:891–896. Frencken JE et al. Minimal

• Control moisture adequately. This can best be achieved with a rubber dam or judicious use of cotton wool rolls and salivary ejectors. Either way, it is essential to protect the preparation from contamination. • Protect the pulp, if indicated, according to contemporary regimes. • Roughen the composite substrate using an intraoral sandblaster (CoJet-Sand, 3M ESPE, Germany; Microetcher, Danville Engineering Company, USA) or diamond bur. Any exposed tooth tissue should also be roughened by sandblasting or with a bur to ensure the removal of any residual composite and pellicle to provide a fresh surface to bond onto. The CoJet sandblaster uses silica sand particles with a mean particle size of 30 microns. The CoJet sandblaster provides a microretentive roughened and silicatised surface which enhances the repair strengths of the repair composite to the composite substrate. • If the composite substrate has not been treated by sandblasting, it must be acid-etched together with the preparation margins for 15-30 seconds and then gently washed and dried using a three-in-one syringe. In addition to producing a favourable

intervention dentistry for managing dental caries – a review. Report of a FDI task group. Int Dent J 2012;62(5):223–243. 8 Bader JD, Shugars DA. Understanding dentists’ restorative treatment decisions. J Public Health Dent 1992;52:102–110. 9 Gordan VV et al. Repair or replacement of defective restorations by dentists in the Dental Practice-Based Research Network Collaborative Group. J Am Dent Assoc 2012;143(6):593-601. 10 Gordan VV. Clinical evaluation of replacement of Class V resin based composite restorations. J

Dent 2001;29:485–488. 11 Blum IR, Schriever A, Heidemann D, Mjör IA, Wilson NHF. Repair versus replacement of defective direct composite restorations in teaching programmes in United Kingdom and Irish Dental Schools. Eur J Prosthodont Restor Dent 2002;10(4):151-155. 12 Blum IR, Schriever A, Heidemann D, Mjör IA, Wilson NHF. The repair of direct composite restorations: an international survey of the teaching of operative techniques and materials. Eur J Dent Educ 2003;7(1):41-48. 13 Blum IR, Mjör IA, Schriever A, Heidemann D, Wilson NHF. Defective direct composite

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substrate surface for bonding, acid etching has a favourable cleansing effect. • If the composite substrate has been treated with the CoJet sandblaster, apply a silane primer and corresponding adhesive (eg. ESPE Sil and Visio-Bond, 3M ESPE) to the substrate and an adhesive bonding system to the adjacent tooth tissues and preparation margins, according to manufacturer’s directions. If the substrate has not been treated with the CoJet sandblaster, an adhesive bonding system should be applied to the acid etched composite substrate and adjacent tooth tissues and preparation margins, according to manufacturer’s directions. Alternatively, a commercially available composite repair system, which includes its own specifically formulated adhesive agent, may be used. Whereas higher bond strengths may be achieved using the CoJet system compared to traditional bonding procedures, only limited data exist to date about the difference in effectiveness between the different techniques. • Apply resin-based composite material using a 2mm incremental technique to repair the defect. Each increment

restorations – replace or repair? A comparison of teaching between Scandinavian dental schools. Swed Dent J 2003;27(3):99-104. 14 Blum IR, Lynch CD, Schriever A, Heidemann D, Wilson NHF. Repair versus replacement of defective composite restorations in German dental schools. Eur J Prosth Rest Dent 2011;19 (2):56–61. 15 Blum IR, Lynch CD, Wilson NHF. Teaching of the repair of defective composite restorations in Scandinavian dental schools. J Oral Rehabil 2012;39(3):210-216. 16 Blum IR, Lynch CD, Wilson NHF. Teaching of direct composite restoration repair in undergraduate dental schools in the United Kingdom and Ireland. Eur J Dent

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must be polymerised using a visible light-curing unit. Ideally, the same type and brand of composite material should be used as the composite substrate, provided this information is known to the practitioner. The composite substrate must be minimum 2mm in thickness for the repair procedure to be successful. • Carefully contour and finish the repair using contemporary composite finishing systems, to leave the repair integrated imperceptibly into the restored tooth unit. • Check the occlusion and correct occlusal interferences, if present.

Repair of fractured tooth tissue adjacent to existing amalgam restoration Clinical procedure • Give local analgesia, as indicated clinically. • Remove any undermined, unsupported tooth tissue and the surface of the amalgam restoration adjacent to the fracture, to provide a fresh surface as a potential bonding substrate. • Prepare retention features within the amalgam restoration to provide mechanical retention for the composite material. • Ensure adequate moisture control,

Educ 2012;16(1):e53-58. 17 Blum IR, Jagger DC, Newton JT, Wilson NHF. The opinions of manufacturers of resin-based composite materials towards the repair of failing composite restorations. Prim Dent Care 2009;16(4):149-153. 18 Lynch CD, Frazier KB, McConnell RJ, Blum IR, Wilson NH. State-ofthe-art techniques in operative dentistry: contemporary teaching of posterior composites in UK and Irish dental schools. Br Dent J 2010;209(3):129-36. 19 Lynch CD, Frazier KB, McConnell RJ, Blum IR, Wilson NH. Minimally invasive management of dental caries: contemporary teaching of posterior resin-based composite















either by applying rubber dam or through judicious use of cotton wool rolls and salivary ejectors. Either way, it is essential to achieve good moisture isolation. Roughen the adjacent amalgam and tooth tissue surfaces using either an intraoral aluminium oxide sandblaster or a diamond bur. If indicated, provide any necessary pulp protection according to contemporary regimes. Acid-etch the tooth tissue surfaces for 15-30 seconds and thoroughly wash and dry the preparation using a three-in-one syringe. Apply an adhesive bonding system to the conditioned tooth surfaces according to manufacturer’s directions. Apply alloy primer and bonding adhesive to the roughened amalgam surface according to manufacturer’s directions. Apply a visible light-cure resin opaquer to the conditioned amalgam surface. The opaquer has a similar chemistry to dental composite resin, and it bonds chemically to the alloy-resin bonding agent and composite resin. Place the repair composite using an incremental technique, light-curing

placement in U.S. and Canadian dental schools. J Am Dent Assoc 2011;142(6):612-20. 20 Liew Z et al. Survey on the teaching and use in dental schools of resin-based materials for restoring posterior teeth. Int Dent J 2011;61(1):12-8. 21 Ben-Gal G, Weiss EI. Trends in material choice for posterior restorations in an Israeli dental school: composite resin versus amalgam. J Dent Educ 2011;75(12):1590-5. 22 Castillo-de Oyagüe R, Lynch C, McConnell R, Wilson N. Teaching the placement of posterior resinbased composite restorations in Spanish dental schools. Med Oral Patol Oral Cir Bucal

2012;17(4);661-8. 23 Lynch CD, Blum IR, Wilson NHF. Repair or replacement of defective resin composite restorations: international trends in dental education. EuroCondenser (Newsletter of the Academy of Operative Dentistry European Section) 2012;14(1):1-3. 24 Setcos JC, Khosravi R, Wilson NH, Shen C, Yang M, Mjör IA. Repair or replacement of amalgam restorations: decisions at a USA and a UK dental school. Oper Dent 2004;29:392–397. 25 Hickel R et al. FDI World Dental Federation – clinical criteria for the evaluation of direct and indirect restorations. Update and clinical examples. Journal of Adhesive

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each increment fully prior to applying subsequent layers of material. • Carefully contain and finish the repair, taking care to have burs and finishing devices work from the composite to the amalgam. • Check the occlusion and correct occlusal interferences, if present.

How successful are repaired restorations? So far, prospective studies have shown that repaired restorations in permanent teeth have the same or increased longevity as restorations that were replaced completely.34-36 Repair treatment remained stable over a seven-year observation period.34,36 The reason why repaired restorations may even outlast those that were replaced probably relates to the fact that most of the restoration’s original form is kept intact, limiting the introduction of new elements that can affect the success of the restoration.26 When other stress factors related to restoration replacement are considered, such as stress on the tooth, post-operative sensitivity, and re-exposure of the dentinal tubules (with possible pulpal reactions to thermal or mechanical stimulus),37-38 damage to the adjacent tooth and the possibility

Dentistry 2010;12:259–72. 26 Hickel R, Brüshaver K, Ilie N. Repair of restorations – criteria for decision making and clinical recommendations. Dent Mater 2013;29(1):28-50. 27 Hickel R et al. Recommendations for conducting controlled clinical studies of dental restorative materials. Clin Oral Investig 2007;11:5–33. 28 Blum IR. The management of failing direct composite restorations: replace or repair? In: Successful posterior composites. Lynch CD, Brunton PA, Wilson NHF, editors. London: Quintessence; 2008. pp.101–114. 29 Blum IR, Jagger DC, Wilson NH. Defective dental restorations: to

of more complex restorations, it makes perfect sense to pursue the repair of defective restorations as a predictable and minimally invasive approach to preserving tooth structure. A recent overview regarding restoration margins concludes that margin defects, without visible evidence of soft dentine on the wall or base of the defect, should be monitored, repaired or resealed, in lieu of total restoration replacement.39 Notwithstanding the plethora of studies published on the repair of RBC materials, there is a lack of data on the longevity of bonded RBC to amalgam surfaces in clinical service. In view of the significant increase in intraoral repair systems available, the growing number of systems being introduced and improvements in the techniques that facilitate alloy-resin bonding, this is rather surprising. Besides being a successful treatment, restoration repair is also practical. Defective restorations can be repaired more quickly and with lower operational costs than replacement. Therefore, repaired restorations could represent a reduction in patient and/or third party expenses that would potentially increase the number of individuals who could

repair or not to repair? Part 1: direct composite restorations. Dent Update 2011;38(2):78-84. 30 Mjör IA, Moorhead JE, Dahl JE. Reasons for replacement of restorations in permanent teeth in general dental practice. Int Dent J 2000;50:360–366. 31 Sharif MO et al. Replacement versus repair of defective restorations in adults: resin composite. The Cochrane Library 2010;2:CD005971. 32 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(10):1276–1282.

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afford dental care. Both oral health and the cost of care are severely impacted by the replacement of existing restorations. Examining outcomes of alternative treatment to the replacement of restorations, and establishing consistent criteria that will affect general practitioners’ treatment decisions, are critical issues which may profoundly change the over-treatment of existing restorations.

33 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. 34 Gordan VV, Riley JL III, Garvan CW, Mondragon E, Blaser PK, Mjör IA. 7-Year results of alternative treatments to defective amalgam restorations. J Am Dent Assoc 2011;142:842– 849. 35 Moncada G, Martin J, Fernández E, Hempel MC, Mjör I, Gordan VV. Sealing, repair and refurbishment of class I and class II defective restorations: a three-year clinical trial. J Am Dent Assoc. 2009;140:425–432.

36 Gordan VV, Garvan CW, Blaser PK, Mondragon E, Mjör IA. A long-term evaluation of alternative treatments to replacement of resinbased composite restorations: results of a seven-year study. J Am Dent Assoc 2009;140:1476–84. 37 Bissada NF. Symptomatology and clinical features of hypersensitive teeth. Arch Oral Biol 1994;39:31S–32S. 38 Hirata K, Nakashima M, Sekine I, Mukouyama Y, Kimura K. Dentinal fluid movement associated with loading of restorations. J Dent Res 1991;70:975–978. 39 Dennison JB, Sarrett DC. Prediction and diagnosis of clinical outcomes affecting restoration margins. J Oral Rehabil 2012;39:301–318.

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Repair versus replacement of defective direct dental restorations in posterior teeth of adults.

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