Mannocci F, Bitter K, Sauro S Present status and future directions: the restoration of root filled teeth. Int Endod J. 2022; 55:1059-1084 https://doi.org/10.1111/iej.13796
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Bhalla VK, Chockattu SJ, Srivastava S, Prasad S. Decision making and restorative planning for adhesively restoring endodontically treated teeth: an update. Saudi Endodontic J. 2020; 10:181-186
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Abu-Awwad M. A modern guide in the management of endodontically treated posterior teeth. Eur J Gen Dent. 2019; 8:63-70
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Using Adhesive Strategies in Molar Rehabilitation after Endodontic Treatment: A Case Series Nikhil Julian Apoorva Walia Tejaswini Shetty Kundabala Mala Manuel S Thomas Dental Update 2025 52:2, 707-709.
Authors
NikhilJulian
BDS, MDS, Private Practitioner, Nikhil Dental Clinic, Kochi, Kerala, India
The shift towards conservative, adhesive, post-endodontic ceramic restorations represents a significant advance in restorative dentistry. By focusing on minimally invasive techniques and the use of adhesive materials, clinicians can achieve better long-term outcomes in terms of tooth preservation, function and aesthetics. The key lies in the careful assessment of each case, ensuring that the chosen restoration aligns with the principles of biomimetic dentistry, which seeks to restore the tooth in a manner that closely mimics its natural form and function. The purpose of this case series is to underscore the significance of adhesive post-endodontic ceramic restorations in the rehabilitation of the form, function and aesthetics of mutilated posterior teeth.
CPD/Clinical Relevance: The use of conservative posterior indirect adhesive restorations can enhance the long-term survival of endodontically treated teeth.
Article
Endodontically treated posterior teeth are more susceptible to fracture owing to several factors, including loss of moisture from the dentine, significant coronal tooth structure loss as a result of carious and non-carious lesions, access cavity preparation and reduced proprioception. Consequently, these teeth are at a greater risk of biomechanical failure.1 In endodontically treated teeth (ETTs), proper coronal restoration is crucial for ensuring favourable outcomes in conjunction with an effective root canal procedure.2,3 The choice of coronal restoration and long-term survival for endodontically treated posterior teeth depends on multiple factors (Table 1).1,3–5
Potential for undue stress on the restoration leading to fracture
Number of neighbouring contacts
Missing adjacent or terminal toothAbutment for denture
Compromised stability and support
Patient
Aesthetic requirement
High aesthetic demand
Need for superior aesthetic solutions
Economic factors
Financial constraints
Limited access to optimal treatment options
Patient compliance
Poor
Risk of inadequate care and follow-up
Operator
Skill
Lacking competency in advanced adhesive protocols
Potential for improper restoration placement and failure
To maintain the harmony between adhesive, mechanical, biological, functional and aesthetic aspects from a biomimetic perspective, the maintenance and conservation of the tooth structure are essential.1 Modern therapeutic practices for restoring ETTs are founded on the concepts of minimally invasive dentistry, which aims to preserve sound tissues. Adhesive procedures are useful for this type of conservative dentistry since they provide adequate material retention without the use of aggressive macro-retention methods.6
This case series aims to discuss and describe the modern, minimally invasive, therapeutic approach based on adhesive concepts using the endocrown and the overlay as restorative modalities for endodontically treated molars.
Case report 1
Clinical examination
A 25-year-old female patient came to the dental clinic requiring a permanent restoration for a previously root canal-treated tooth. On examination, the adequately obturated LR7 was temporized with zinc oxide eugenol (Figure 1).
Figure 1.
(a) Pre-operative image of tooth LR7 with a temporary restoration. (b) Residual tooth structure after temporary restoration. (c) Limited interocclusal space was available for restoring the tooth. (d) Tooth preparation for the endocrown with a cervical wall of enamel and a pulp chamber depth of 3 mm with blocked-out undercuts. (e) Post-operative image after cementation of lithium disilicate-based endocrown. (f) Lateral view after endocrown post-cementation.
Tooth preparation and cavity design optimization
Removal of the temporary restoration resulted in extensive gouging of the dentinal walls, with only a peripheral rim of enamel remaining (Figure1b). The quality of the residual tooth structure was poor, and the interocclusal clearance was minimal (Figure 1c). Therefore, an endocrown was chosen as the appropriate treatment option to preserve the remaining pericervical dentine as much as possible.
During the first visit, the tooth was built up with composite resin (Filtek Z350XT, 3M ESPE, St Paul, MN, USA) to optimize the cavity for final preparation. Final curing was carried out under a water-soluble gel. A 2-mm occlusal clearance, along with a 2-mm cervical sidewalk, were created using a wheel-shaped bur (WR 13 MANI, Tokyo, Japan). A 5° divergence and 3-mm depth were maintained using a round-end taper diamond bur (TR 12, MANI, Tokyo, Japan) for the pulp chamber (Figure 1d).7 The shade was recorded using the VITA classical shade guide (Vita Zahnfabrik, Bad Säckingen, Germany).
Impression technique
A double-mix, single impression was taken using putty and light body material (Aquasil Putty, Dentsply, NC , USA), followed by bite registration using AluWax (Maarc Dental, Delhi, India).
Restoration fabrication and cementation
At the following appointment, a lithium disilicate (LS2) endocrown (IPS e.max press, Ivoclar Vivadent, Schaan, Lichtenstein) was cemented under a rubber dam using the protocol outlined in Table 2 (Figure 1). Regular post-operative follow-up was conducted for the patient.
Steps
Step 1: Micro-roughening and cleaning
Step 2: Priming and adhesive application
Step 1(a): Preparation of the intaglio surface of the lithium disilicate restoration
Etching with 10% hydrofluoric acid gel for 10 seconds and ultrasonic cleaning
Application of the silanating agent, allowing to dry for 60 secondsApplication of universal bonding agent with dark activator
Step 1(b): Preparation of the tooth before cementation
Mechanical roughening (air abrasion/diamond bur) of sealed dentine and compositeSelectively etching peripheral enamel for 15 seconds with 37% phosphoric acid followed by thorough rinsing and drying
Thorough application of universal bonding agent, followed by air-shearing
Step 2: Cementation
Application of the dual-cure resin cement. Tack-curing restoration for 3 seconds. Final co-curing all surfaces for 60 seconds each
Step 3: Finishing and polishing
Final finishing and polishing using rubber cups and polishing pastes, and an occlusal check. Excess interproximal cement was removed
Case report 2
Clinical examination
A 35-year-old female patient visited the dental office with a chief complaint of severe pain in the lower right posterior tooth region, which worsened during the consumption of hot or cold food. The pain was spontaneous and radiated toward the right side of her face. Upon clinical and radiographic examination, LR6, which had a deep and faulty amalgam restoration (Figure 2), was diagnosed with symptomatic irreversible pulpitis.
Figure 2.
(a) Large, failing amalgam restoration with respect to LR6. (b) Tooth prepared for ceramic overlay. (c) Cementation using dual-cure resin cement. (d) Cemented restoration after clearing the excess cement. (e) Post-operative occlusal view after cementation of the overlay. (f) Lateral interocclusal view post cementation.
Endodontic treatment
Root canal treatment was performed for LR6. The previous amalgam restoration was entirely removed, and the pulp chamber was cleaned to remove residual sealer. Next, the cavity was restored with a composite (Filtek Z350XT, 3M ESPE).
Tooth preparation and impression
Since the thickness of the residual cusps was <2 mm, cuspal coverage was indicated. Compared with a traditional crown, an indirect LS2 overlay was selected as a suitable treatment option because it preserves the maximum amount of hard tissue and maintains the structural integrity of the tooth. The tooth was prepared for an IPS e.max press overlay involving all the cusps and exposing the enamel at the periphery to optimize bonding (Figure 2).4,5 After tooth preparation, impressions were taken.
Cementation
At the following appointment, cementation of the IPS e.max restoration was carried out under a rubber dam using the protocol outlined in Table 2 (Figure 2).
Case report 3
Clinical examination
A 65-year-old male patient presented with a chief complaint of severe spontaneous pain in the left upper molar. On clinical and radiographic examination, deep lesions both proximally and cervically on UL6 and UL7 were identified (Figure 3).
Figure 3.
(a) Intra-oral peri-apical radiograph showing proximal subgingival caries with respect to UL6 and UL7. (b) buccal aspect of UL6 and UL7 with cervical defect. (c) Subgingival defect on the mesial aspect of the molars after removal of old restorations. (d) Deep marginal elevation, cavity design optimization and tooth preparation. (e) IPS e.max press overlay veneer restoration from the laboratory ready for adhesive cementation. (f) Post-operative occlusal view. (g) Buccal view after cementation showing the aesthetic and functional blend. (h) Post-operative peri-apical radiograph of root canal treatment and restoration.
Diagnosis and treatment planning
The involved teeth were diagnosed with symptomatic irreversible pulpitis with severe loss of coronal structure. Given the patient's priority to preserve the tooth, and considering that a post and full coverage crown were not feasible owing to the absence of continuous ferrule, an adhesive indirect restoration was chosen.
Endodontic treatment
UL6 and UL7 were treated endodontically. The patient was then recalled for permanent restoration after 10 days.
Deep margin elevation and cavity design optimization
At the subsequent visit, following the removal of the temporary restoration, the defect was analysed. Deep margin elevation (DME) was performed using the modified Tofflemire matrix technique, as described by Magne and Spreafico.8 The cervical defect, as well as the inner surface of the teeth, were restored with a composite, and a cervical sidewall with a central cavity of 2 mm was prepared.
Teeth UL6 and UL7 were prepared for ceramic onlays. For UL7, a butt joint occlusal finish line with a mesial cavity was used. The UL6 tooth had a distal box and central cavity, and the distopalatal cusp was capped, with a deep chamfer margin. The butt joint was maintained for the buccal cusp (Figure 3). Immediate dentine sealing was performed, and the enamel margins were refreshed with a slow-speed diamond point. Impressions were then taken.9
Cementation
At the following visit, the IPS e.max restorations (Figure 3) were cemented following the protocol outlined in Table 2. Subsequently, the proximal marginal integrity of the adhesive restorations was assessed using an intra-oral peri-apical radiograph (Figure 3). The teeth have been kept under constant follow-up.
Discussion
The traditional approach to restoring endodontically treated posterior teeth typically involves the placement of a full-coverage crown. It has been shown that preparation for a conventional crown can result in the removal of up to 70% of the coronal hard tissue, thereby reducing its fracture resistance.10,11 The periodontal health of teeth may also be compromised when subgingival margins are placed for full crowns.12
In contrast to traditional methods, minimally invasive bonding techniques actively contribute to the conservation of existing dental tissues and the maintenance of periodontal integrity.4 This approach balances the functional and aesthetic requirements of patients, offering a preferable solution. Options such as onlays, overlays and endocrowns have emerged as minimally invasive treatments for addressing extensive defects.6 These collectively fall under the category of posterior indirect adhesive restorations (PIAR).13 The success of PIAR is largely dependent upon the preparation design, the ceramic chosen and the highly technique-sensitive adhesive luting protocol. Several concepts are important for the long-term clinical success of these indirect restorations, including immediate dentine sealing (IDS), cavity design optimization (CDO) and DME.14
IDS aims to seal all dentinal surfaces while keeping the cavity isolated and helps to prevent dentine contamination, thereby improving the bond strength.15 Other important aspects of indirect restorations are CDO and DME, where needed. They both help prevent unnecessary loss of tooth structure and result in predictable bonding. To avoid the loss of tooth structure by preparing the undercuts, a liner can be placed to provide free-flowing margins to the restoration, and a divergent profile can be obtained that provides a single path of insertion. The concept of DME was introduced to ease the process of impression taking and isolation during cementation for deep proximal preparations. A highly filled composite with a width of 1–1.5 mm is used for this purpose.14
Now, we turn our attention to the ceramic material of choice, which is LS2. It possesses good compressive strength when applied at sufficient thickness and, above all, it is etchable with hydrofluoric acid, making it suitable for adhesive retention.16 Regarding the bonding protocol, the use of a rubber dam is a prerequisite, primarily owing to the technique sensitivity inherent in the adhesive procedure. Adhesive bonding for these ceramic restorations is possible only with appropriate substrate preparation, which requires a strict bonding protocol and good moisture control with the help of a rubber dam.1
Compared to anterior teeth, molars are subjected to more occlusal load. However, these loads are primarily directed along the long axis of the teeth.5 Therefore, the material chosen should have sufficient compressive stress and thickness to withstand these occlusal loads. Since the shear stresses acting on posterior teeth are minimal, intra-radicular posts in indirect prostheses are not required for retention unless severe loss of tooth structure is noticed. Additionally, molars offer a greater amount of enamel for bonding than anterior teeth, and the larger pulp space in molars further contributes to the retention of PIARs (Table 3).14
Indication
Contraindication
Medium-to large-sized cavities where one or more cusps are missingPresence of adequate peripheral enamelTeeth with no ferruleMorphological modification and/or raising of the posterior occlusal vertical dimension, especially in cases with limited pericervical dentine
Patients with parafunctional habitsExtensive loss of coronal tooth structure with no to less peripheral enamel and inadequate pulp chamber depthTooth for which adequate isolation cannot be achieved
Endocrowns are ceramic monoblocks that can be bonded adhesively to the internal aspect of the pulp chamber of an endodontically treated tooth, which aids in both macro- and micromechanical retention.1,3–7 They are indicated as an appropriate restorative option for severely compromised teeth that lack adequate vertical dimensions and do not have a ferrule effect but possess a deep pulp chamber (Table 3).3
As was observed in Case 1, the patient lacked adequate vertical height, but there was enough healthy enamel tissue present, which provided the cervical sidewalk for bonding. Moreover, the central cavity could be used for retention instead of intra-canal posts, which would avoid the risk of fracture in the future.5 Endocrowns are reported to have a slightly greater success rate in molars than in premolars owing to the larger pulp chambers and lower lateral forces acting on molars.17
Bonded restorations that are mechanically non-retentive and have no intra-coronal portion with complete occlusal coverage are termed overlays. They seem to provide a more homogenous distribution of occlusal forces during function and have a better cavity design, which reduces the C factor and causes less polymerization shrinkage on the marginal surfaces.4
In the second case in this article, there was a large, failing amalgam restoration; upon removal of the same, the entire occlusal surface needed to be capped, and the same was done using an LS2 overlay to create a biodome effect that increased fracture resistance.18
Overlays are conservative treatment options for patients with significant loss of coronal tooth structure requiring total occlusal coverage in teeth with minimal to moderate occlusal load (Table 3).
In clinical situations where one or two cusps require coverage and there is also an intracoronal component, a ceramic onlay can be used because it can cover the adjacent occlusal surface or the entire surface depending upon the requirements and is retained adhesively.5 This approach can be used in situations requiring cuspal coverage while preserving the maximum amount of healthy tooth structure, as was observed in the third case, where the molar had a deep mesio-occlusal cavity that was covered with the help of an LS2 onlay.
In a study performed by Malament et al to evaluate the difference in survival between full-coverage crowns and partial-coverage ceramic onlays, there was no significant difference in survival, and the estimated survival rate for both restorations that were older than 16.9 years was 96.5%.19
Compared to conventional full crowns, posterior indirect adhesive restorations offer several advantages. They are suitable for patients with high aesthetic demands, preserve healthy tooth structure and provide long-term survival when restoring endodontically treated posterior teeth, provided that proper selection criteria and protocols are followed.4
Conclusion
In the current era of advanced adhesive techniques, full-coverage crowns are no longer the sole treatment option for endodontically treated posterior teeth. There is a growing trend toward transitioning from traditional, invasive tooth preparations for crowns to conservative preparations for posterior indirect adhesive restorations.
These modern, conservative restorations offer significant benefits, allowing the natural tooth structure to be preserved while effectively restoring both function and aesthetics. By adopting these newer methods, dental professionals can achieve better outcomes for patients, maintaining the structural integrity of the teeth and ensuring long-term oral health.
