Removal of Bonded Ceramic Restorations: A Guide to Technique Selection

In contemporary restorative dentistry, adhesive cementation and high-strength ceramics have significantly improved the longevity and retention of indirect restorations.^1,2 However, when these restorations require removal, the same properties that ensure long-term success make retrieval a complex procedure.^3,4 Inappropriate removal techniques can result in thermal injury, iatrogenic periodontal damage, ceramic fracture, and excessive loss of sound tooth structure.^5-7 These risks are compounded by the increasing prevalence of zirconia and lithium disilicate restorations, which present distinct challenges during removal due to their hardness, fracture behavior, and optical properties.⁸

This article provides an overview of the techniques available for removing bonded (adhesively cemented) indirect restorations; examines how adhesive mechanisms and material properties influence technique selection; and presents a clinical decision framework for safe, predictable retrieval.

Adhesive Bonding and Retention Mechanisms

The type of cementation used directly influences the difficulty of removal. The two primary approaches are conventional luting and adhesive cementation.¹ Conventionally luted restorations rely primarily on mechanical retention from the preparation geometry, with luting agents such as zinc phosphate or glass ionomer filling the interface.³ Adhesively cemented restorations use primers and resin cements to form chemical bonds with tooth structure, producing higher cohesive strength and fracture toughness (KIc) at the interface.^2,9

Bonding protocols differ by material. For zirconia, successful adhesion is achieved through air-particle abrasion, application of a 10-MDP-containing primer, and resin cementation.¹⁰ For glass ceramics such as lithium disilicate and feldspathic porcelain, the protocol involves hydrofluoric acid etching, silane coupling agent application, and resin cementation.¹¹ The silane coupling agent functions as a bifunctional molecule that enhances bonding between the ceramic surface and the resin cement.¹²

Removal Techniques

Removal systems have been classified into conservative techniques that preserve the restoration for reuse, semiconservative techniques that require minor repair, and destructive techniques that sacrifice the restoration entirely.^3,4 Several factors should be assessed before attempting removal, including remaining tooth structure, cementation type, restoration design and material, periodontal status, preparation taper, and direction of force application.⁴  The techniques are described below and in Table 1.

Sectioning (Crown Splitting) with Rotary Instruments

Sectioning is the most widely used destructive technique.^3,4 The technique involves placing one to two buccolingual grooves through the restoration using a high-speed handpiece with a coarse diamond bur, then inserting a crown splitter or spreader to fracture the restoration and break the luting agent seal.⁴ This method is best indicated when restoration reuse is not intended, particularly for monolithic zirconia and metal or porcelain-fused-to-metal (PFM) restorations.

The primary risk is heat generation. Without adequate water irrigation, the intrapulpal temperature can exceed the 5.5 degrees C threshold associated with irreversible pulpitis.^5,6 Differences in thermal conductivity and coefficient of thermal expansion among ceramic materials may further influence heat transfer behavior during sectioning.⁸

Ultrasonic Vibration

Ultrasonic removal is a conservative approach that aims to preserve the restoration. Scaler tips placed at the restoration margins vibrate at 20,000 to 40,000 cycles per second, inducing fatigue fractures in the luting agent and gradually weakening the bond.^4,13 This technique is especially useful for metal and PFM restorations cemented with conventional luting agents and has been shown to significantly reduce the debonding force of cemented lithium disilicate laminate veneers.¹³ Prolonged application can cause porcelain chipping and heat generation, necessitating continuous water cooling.⁵ Ultrasonic techniques are also contraindicated in patients with cardiac pacemakers and certain infectious conditions.⁴

Crown Removal Devices (Crown Pullers)

Crown removal devices deliver controlled tensile or impact force to break the retention of conventional luting agents. These include sliding hammers, pneumatic instruments, and grasping forceps with rubber-tipped jaws.⁴ They are best indicated for restorations cemented with zinc phosphate or polycarboxylate luting agents and for provisional restoration removal. Thermoplastic adhesive resins such as the Richwil system offer an additional conservative option, with reported success rates of 100% for provisional and 60% for permanent restorations when combined with ultrasonics.⁴ Semiconservative systems, such as the Metalift, WAMkey, and buccolingual dimple technique, allow removal with minor restoration repair through small access holes or surface modifications.^4,14

Crown removal devices carry risks of trauma to the tooth, root, and periodontium, particularly with excessive or misdirected force.³ For adhesively cemented restorations, these devices alone are generally insufficient and are used as adjuncts following weakening of the luting agent by ultrasonics or laser application.

Laser Debonding

Laser-assisted debonding provides a minimally invasive approach for removing bonded ceramic restorations. An erbium-doped yttrium-aluminum-garnet (Er:YAG) laser operating at a wavelength of 2940 nm is applied to the external surface of the restoration.¹⁵ The laser energy passes through translucent ceramic materials and is absorbed by water and organic components of the underlying resin cement, causing thermal ablation that weakens the luting agent.^15,16 Following laser application, the restoration can be gently removed using a hand instrument or crown removal device.

Laser debonding is particularly effective for lithium disilicate restorations, with mean debonding times of approximately 1.1 to 1.7 minutes, while zirconia restorations require approximately 4.8 to 5.8 minutes.¹⁶ Validated parameters include 335 mJ, 15 Hz, and 5.0 W with a pulse duration of 50 ms,¹⁶ with power settings of 5.9 W reported as both effective and safe for lithium disilicate crowns of 1.5 mm and mixed thicknesses.¹⁵ The type of adhesive resin cement does not appear to significantly affect debonding time.¹⁶ When performed with appropriate parameters, intrapulpal temperature rise can be maintained below the critical 5.5 degrees C threshold.¹⁵

Opaque materials such as gold and PFM prevent laser transmission to the luting agent, excluding them from laser-assisted removal. Laser debonding also requires significant capital investment and operator training. Overall success rate for zirconia abutments on natural and implant restorations is 95%.²⁴

Restorative Material Properties and Removal Implications

The physical properties of the restorative material directly influence which removal approach is most appropriate.³ Three properties are particularly relevant, as described below and in Table 2.

Fracture Toughness

Fracture toughness (KIc) describes the resistance of a material to crack extension under mechanical stress.¹⁷ Among conventional ceramics, zirconia exhibits the highest fracture toughness, in part due to phase transformation toughening,⁸ followed by lithium disilicate, with feldspathic ceramics being most susceptible to chipping and fracturing during removal.^8,18 Materials with lower fracture toughness are more likely to fragment unpredictably during sectioning, complicating the procedure. Conventional rotary removal of ceramic crowns requires high-speed bur sectioning that generates particulate debris and involves mechanical disruption of the restoration, introducing procedural risks and supporting the use of less destructive removal approaches when feasible.¹⁹

Hardness

The hardness of a ceramic, measured as Vickers hardness number (VHN), determines its resistance to localized surface deformation. Zirconia has the highest VHN at approximately 1,400 to 1,500, followed by lithium disilicate at approximately 600.^20,21 Due to its high hardness, zirconia is significantly more difficult to section, requiring more time at constant pressure.²² Contrary to the common perception that coarser instruments are more effective for cutting hard ceramics, fine-grit diamond burs (red band, 40 to 50 micrometers) have demonstrated greater cutting efficiency on zirconia with less substrate damage and less instrument deterioration.²³ Dedicated zirconia-cutting diamond burs have also shown superior efficiency for zirconia sectioning compared with conventional coarse-grit instruments.²²

Translucency

Translucency, defined as the property of a material having an appearance between complete opacity and complete transparency, varies significantly among ceramics. Feldspathic ceramics exhibit the highest translucency, followed by lithium disilicate, with zirconia being most opaque.⁸ During removal of highly translucent restorations, distinguishing between the restoration and underlying tooth structure is a significant challenge, particularly with shade-matched core build-ups and resin cements.²⁴ Laser debonding offers a distinct advantage by targeting the luting agent without requiring visual differentiation.

Clinical Decision Framework

Selecting the appropriate removal technique begins with determining whether a restoration is conventionally luted or adhesively cemented, based on restoration type, luting agent margin appearance, known bonding protocols, and material properties.³

For adhesively cemented restorations, clinicians should anticipate high retention strength. Zirconia restorations are best managed through sectioning with fine diamond burs under copious irrigation. Lithium disilicate crowns and veneers are candidates for Er:YAG laser-assisted debonding when equipment and expertise are available.^15,16 Crown removal devices and ultrasonic energy can serve as adjuncts, particularly for conventionally luted restorations.

Conclusion

The removal of bonded indirect restorations requires a material-specific, biologically informed approach. Sectioning remains the most reliable technique for most adhesively cemented restorations, particularly zirconia, while Er:YAG laser-assisted debonding offers a conservative alternative for translucent ceramics such as lithium disilicate. Matching removal strategy to the fracture toughness, hardness, and translucency of the restorative material allows clinicians to anticipate procedural challenges and select the safest approach. As laser technology becomes more accessible, clinical studies comparing removal techniques across ceramic types and cementation protocols will be essential to establish evidence-based
guidelines.

Acknowledgment

The authors would like to thank the faculty of RSDM5511 at the Dental College of Georgia at Augusta University for their educational support.

Conflicts of Interest

The authors declare no conflicts of interest.

Figures and Images

Table 1

Figure 1

Table 2

Figure 2

Rafael Rocha Pacheco, DDS, MSc, PhD

Andrew Mancao, DMD Candidate

Navid Khorashahi, DMD Candidate

Ryan O’Donnell, DMD Candidate

Ethan Walden, DMD Candidate

Ronald Harris, DDS

Eduardo Britton, DDS

Table 1

Figure 1

Diamond rotary instruments of varying grit sizes used for ceramic crown sectioning. From left to right: coarse (green band, ~150 micrometers), medium (blue band, ~100 micrometers), fine (red band, ~40 micrometers), superfine (yellow band, ~15 micrometers), and ultrafine (white band, ~8 micrometers).

Table 2

Figure 2

Clinical decision tree for bonded ceramic restoration removal. Technique selection is guided by cementation type, restorative material, and preservation intent. Green boxes indicate conservative approaches. All pathways require continuous water irrigation to maintain intrapulpal temperature below the 5.5 degrees C threshold.5,6

Rafael Rocha Pacheco, DDS, MSc, PhD

Associate Dean for Digital Technologies and Associate Professor Department of Restorative Sciences Dental College of Georgia Augusta University Augusta, Georgia

Andrew Mancao, DMD Candidate

Dental College of Georgia Augusta University Augusta, Georgia

Navid Khorashahi, DMD Candidate

Dental College of Georgia Augusta University Augusta, Georgia

Ryan O’Donnell, DMD Candidate

Dental College of Georgia Augusta University Augusta, Georgia

Ethan Walden, DMD Candidate

Dental College of Georgia Augusta University Augusta, Georgia

Ronald Harris, DDS

Assistant Professor Department of General Dentistry Dental College of Georgia Augusta University Augusta, Georgia

Eduardo Britton, DDS

Assistant Professor Department of General Dentistry Dental College of Georgia Augusta University Augusta, Georgia