European Journal of General Dentistry

REVIEW ARTICLE
Year
: 2019  |  Volume : 8  |  Issue : 3  |  Page : 63--70

A modern guide in the management of endodontically treated posterior teeth


Motasum Abu-Awwad 
 Department of Prosthodontics, School of Dentistry, University of Jordan, Amman, Jordan

Correspondence Address:
Dr. Motasum Abu-Awwad
Department of Prosthodontics, School of Dentistry, University of Jordan, Queen Rania Street, Amman 11942
Jordan

Abstract

Decision-making in the management of posterior endodontically treated teeth (ETT) is still considered a challenge for the clinician. The development of adhesion has led to a paradigm shift in the restorative treatment options. Restorations which depend on mechanical retention are not the only restorations currently available. Adhesive restorations are gaining more popularity due to their conservative nature. This article aimed to provide the clinician with a modern guide for the management of posterior ETT using adhesive restorations. A method of assessment of the remaining tooth structure which places the tooth in one of the three categories was recommended, and adhesive treatment options were suggested for each category. The three categories were minimally destructed teeth, which could be managed simply through intracoronal composite resin restorations; moderately destructed teeth, which could be managed through adhesive overlays; and severely destructed teeth, which could be managed through fiber post–core–crown combination, or through endocrowns.



How to cite this article:
Abu-Awwad M. A modern guide in the management of endodontically treated posterior teeth.Eur J Gen Dent 2019;8:63-70


How to cite this URL:
Abu-Awwad M. A modern guide in the management of endodontically treated posterior teeth. Eur J Gen Dent [serial online] 2019 [cited 2019 Nov 15 ];8:63-70
Available from: http://www.ejgd.org/text.asp?2019/8/3/63/266697


Full Text



 Introduction



With the vast advances in adhesive dentistry, multiple restorative treatment options are available nowadays to restore endodontically treated teeth (ETT).[1] However, determining whether cuspal coverage is needed or not, followed by selecting a suitable treatment option for each clinical situation, could be challenging for the restorative dentist.[2]

A paradigm shift in dentistry has occurred in the last decades. Conventional methods of restoring teeth, which depend on mechanical retention, are being replaced by modern methods which depend on adhesion.[3] This shift was attributed to the increased popularity of the minimally invasive dentistry philosophy, and the development of reliable adhesive systems, as well as the etchable ceramics.[4] A summary of the available conventional mechanically retained restorations and their modern adhesively retained alternatives is presented in [Table 1].{Table 1}

The use of mechanically retained restorations is supported by long-term studies, and these restorations have demonstrated good reliability and predictability as treatment options for restoring ETT.[5],[6] However, their use is not without biological cost.[7] On the other hand, the conservative nature of the adhesive restorations offers many advantages over the mechanically retained restorations.

Conservation of tooth structure

Because adhesive restorations do not require extra tooth preparation to achieve resistance and retention form, conservative preparation designs with maximal preservation of tooth structure could be used.[8] The strength and fracture resistance of the tooth has been shown to be positively related to the amount of the tooth structure remaining.[9],[10] In addition, a conservative preparation will reduce periodontal problems because the margins are usually supragingival.[11],[12]

Controlled mode of failure

The conservative nature of the adhesive restorations may keep the possibility of a re-intervention available once a failure occurs. Moreover, conservative restorations will reduce the risk of irreversible fractures. This will delay the restorative cycle described by Elderton, and therefore increase the longevity of the tooth.[1],[13]

Reduction in time and cost of treatment

The fabrication of a conventional crown may involve many clinical and technical steps, such as crown-lengthening procedure, post cementation, core fabrication, and temporization, which would increase the time and cost of treatment.[14] Many of these steps could be avoided through the use of adhesive methods, where the retention of the restoration is dependent on adhesion rather than mechanical retention.[15]

The survival and success of ETT is significantly influenced by the choice of appropriate restorations. Many studies have reported full cuspal coverage to be the treatment of choice for posterior ETT.[5],[6] The rationale behind providing full-coverage crowns is the protection of ETT from potential future cracks and fractures. This is due to the reduced structural integrity and stiffness associated with the loss of tooth structure in ETT.[16] However, recently, few studies in the literature have reported good longevity for posterior ETT when restored with direct intracoronal restorations without the provision of cuspal coverage, specifically for teeth with limited amounts of structural loss.[17],[18] Therefore, using a full-coverage crown where it could have been avoided might be considered an unnecessary removal of valuable tooth structure which could have been otherwise preserved.[19]

A recent systematic review has found insufficient evidence to compare full cuspal-coverage restorations to direct restorations when used for restoring ETT and suggested that the clinicians should make their clinical decisions based on their own clinical experience.[20] In order to assist the clinicians in the decision-making process, decision flowcharts based on prosthodontic principles for restoring ETT were suggested previously.[21] Although such flowcharts were considered helpful by many clinicians, they do not fulfill the modern requirements of conservative adhesive dentistry and do not include the adhesive restorative options currently available.[1] More recently, an online tool has been developed to facilitate access to summaries of the available evidence to help dentists in decision-making regarding the need for cuspal coverage or intracoronal restorations.[22] However, this tool still did not incorporate a guide to aid in choosing between mechanically retained and adhesive restorations.

Therefore, the aim of the current article was to provide the restorative dentist with a simple evidence-based modern guide for the decision-making process in the management of posterior ETT. The guide offers a method of assessment and categorization of the remaining posterior tooth structure and suggests adhesive restorative treatment options for each category.

 Restorative Decision-Making Protocol



The protocol starts with an assessment of the amounts of tooth structure loss and an assessment of any modifying factors which lead to unfavorable occlusal loading. This is followed by choosing a suitable conservative treatment option for each clinical situation.

Step 1: Assessment of the amount of tooth structure loss and any modifying factors

The assessment should be done after removal of any caries or old restorations and after finishing an endodontic access cavity when needed. This is an essential step because the type of definitive restoration chosen to restore the tooth will be influenced by the amount of tooth structure remaining after tooth preparation.[23] Understanding which part of the tooth structure is most important in keeping its fracture resistance and stiffness is fundamental for an accurate assessment of the strength of the remaining tooth structure.[1],[24]

The marginal ridges

The marginal ridge has been shown to be critical in the maintenance of tooth stiffness and limiting excessive cuspal deflection.[16],[25],[26] It was found that the loss of tooth stiffness was 20% for an occlusal cavity, compared to 45% for a mesio-occlusal (MO)/disto-occlusal (DO) cavity and 63% for a MO-distal (MOD) cavity.[16] In another investigation to evaluate the effect of different thicknesses of the marginal ridge on fracture strength of endodontically treated maxillary premolars with DO cavities restored with intracoronal composite resin restorations, it was reported that a marginal ridge thickness of >1 mm preserved the fracture resistance of the teeth. Whereas, a 0.5-mm marginal ridge thickness led to a significant reduction in the tooth fracture resistance compared to the level of intact teeth.[27] The removal of both marginal ridges in MOD cavity preparation produced a dramatic increase in cuspal deflection compared to MO/DO cavity preparation.[25],[28]

The buccal and palatal/lingual axial walls

The wider the cavity preparation, the thinner the remaining axial walls' thickness. The remaining wall thickness was reported to be an important factor in the resistance to fracture under occlusal load.[29] An axial wall thickness of <2 mm was noted to reduce the tooth resistance to fracture in endodontically treated premolars, and it was suggested that cuspal coverage would be needed to improve the fracture resistance.[30]

The endodontic access cavity

A reduction of only 5% of tooth stiffness was measured by Reeh et al. when a conservative endodontic access cavity was carried out before or after any restorative preparations, whereas a wider occlusal cavity was associated with 20% reduction in tooth stiffness.[16] An endodontic access cavity and an occlusal cavity surely will involve removal of the same tooth structure. However, the difference in reduction of the tooth stiffness was reported to be fourfold for an occlusal cavity compared to an endodontic access cavity. This significant difference was attributed to the possibility of greater encroachment of an occlusal cavity preparation on the marginal ridge area compared to an endodontic access cavity.[16] Similar results were reported in another study, which found that the fracture resistance of teeth with conservative access cavities alone was close to that of an intact tooth.[31] However, another study reported an increase of 2–3 folds of cuspal deflection when an endodontic access cavity was carried out for MO/DO and MOD cavities. This increase in cuspal deflection in the ETT was attributed to the increased depth associated with an access cavity preparation.[28] The contrasting findings between these studies could be attributed to the difference in the amount of tooth structure removed during the access cavity preparation. Studies which were based on conservative endodontic access cavities prepared within the confines of the occlusal cavity floor, with dentine remaining between the access opening and both proximal boxes, showed reduced loss of stiffness.[16],[31] Whereas, studies in which the endodontic access included removal of the dentin between the pulp chamber and the proximal boxes showed increased loss of stiffness.[28]

As previously mentioned, many studies in the literature reported higher risk of fracture for ETT and better survival rates with cuspal coverage.[5],[6],[32],[33] However, these studies did not take into account the amount of remaining tooth structure prior to providing cuspal coverage. ETT with a MOD cavity will have higher risk of fracture than ETT with just an occlusal cavity.[16] Therefore, managing both with cuspal coverage could be considered an overtreatment and an unnecessary removal of tooth structure. Because the strength and fracture resistance of the tooth has been shown to be positively correlated with the amount of tooth structure remaining, more conservative treatment options should be selected for ETT.[9],[10],[18]

A simple classification, which was recently suggested, could be followed to give an initial assessment of the tooth condition. The classification sets the posterior teeth into one of the three categories depending on the amount of tooth structure lost. The three categories were referred to as minimally destructed teeth, moderately destructed teeth, and severely destructed teeth.[34]

Minimally destructed ETT were defined as teeth with an occlusal cavity or a MO/DO cavity with thick remaining axial walls (≥2 mm). This category of teeth does not necessarily require cuspal coverage to have good longevity. A few clinical studies supported this decision. In one retrospective clinical study, endodontically treated molars with occlusal cavities restored with intracoronal restorations were reported to have 78% survival rate over 5 years.[17] Good survival rates for endodontically treated premolars with minimal MO/DO cavities were reported over 3 years without the need for cuspal coverage.[18] Other studies reported similar findings for ETT with three axial surfaces when restored adhesively with composite resin restorations.[35] These clinical findings were also supported by in vitro studies.[16],[31]

Moderately destructed ETT were defined as teeth with a MO/DO cavity with thin remaining axial walls (<2 mm) or a MOD cavity. The teeth in this category have reduced fracture resistance due to the amount of tooth structure lost and would probably benefit from cuspal coverage. This clinical decision was supported by multiple studies in the literature.[5],[16],[28],[29],[30],[31]

Severely destructed ETT were defined as teeth with tooth structure loss beyond a MOD cavity. The teeth in this category would have suffered from large amount of tooth structure loss and would definitely benefit from cuspal coverage. Cuspal coverage in these clinical cases would also facilitate the reestablishment of the lost occlusal anatomy.[34]

Following choosing the best matching category for the posterior tooth in question, an account for key modifying factors, which lead to unfavorable occlusal forces, should be made. The first modifying factor is parafunctional habits which subject the tooth to increased occlusal forces, such as bruxism. People who grind their teeth can subject their teeth and restorations to significant amount of destructive occlusal forces.[36] Parafunctional habits should be taken into consideration when a decision is made about the need for cuspal coverage and the restorative material which could withstand such forces.

The second modifying factor is lateral occlusal forces. Lateral occlusal forces are more destructive to the tooth than axial occlusal forces.[37] When testing premolars using different loading directions, premolars which were subjected to lateral occlusal loads were at higher risk of fracture than those subjected to axial occlusal loads.[38] This factor could be crucial for the longevity of ETT and their restorations, which should be considered in the decision-making process.[39]

The third modifying factor is the number of proximal contacts for the tooth. Having proximal contacts was reported to favorably dissipate the occlusal load to the adjacent teeth. Therefore, ETT with only one proximal contact or without adjacent proximal contacts are subjected to unfavorable distribution of occlusal forces. This has been shown to impact the survival rates of ETT.[19]

Any of these modifying factors might alter the clinical decision regarding the most appropriate treatment option. A tooth which falls under the minimally destructed category might be considered for cuspal coverage in the presence of any of these modifying factors. Now that an assessment has been made of the amount of tooth structure loss and the key modifying factors, the next step would be to select the most appropriate treatment option.

Step 2: Choosing a conservative treatment option for each clinical situation

Depending on the category selected for the tooth, the most conservative treatment option which provides the tooth with predictable longevity should be selected. In addition, the most esthetic treatment option should also be considered if the tooth falls in the esthetic zone.[1] It is also important to keep in mind that teeth with subgingival cavities due to caries or fractures are usually difficult to restore with adhesive restorations. This is attributed to the difficulty in achieving good isolation to obtain a dry field necessary for the bonding procedure. In these situations, the clinician should opt for a mechanically retained restoration. Otherwise, clinical crown-lengthening procedure might be considered to improve the margin location and facilitate the bonding procedure.

Minimally destructed teeth

As mentioned previously, minimally destructed teeth have sufficient tooth structure to survive without the need for cuspal coverage. Therefore, they can be managed through intracoronal composite resin restorations with good longevity.[17],[18] However, in the presence of a modifying factor leading to an increase of the occlusal loads, a clinical decision for the need of cuspal coverage should be considered. An example of a minimally destructed premolar tooth is presented in [Figure 1]a. Assessment of this endodontically treated mandibular second premolar reveals a DO cavity and axial wall thickness (≥2 mm). There were no lateral forces on the tooth and the patient had no parafunctional habits. This tooth was managed through an intracoronal composite resin restoration [Figure 1]b.{Figure 1}

Moderately destructed teeth

Moderately destructed ETT would benefit from cuspal coverage. They could be managed through mechanically retained indirect restorations such as partial-coverage or full-coverage crowns.[5],[6],[34] They could also be managed through adhesively retained restorations such as adhesive onlays or overlays.[1],[40]

An onlay is defined as a partial-coverage restoration that restores one or more cusps and adjoining occlusal surfaces or the entire occlusal surface, and is retained by mechanical or adhesive means. Thus, an onlay by its definition can refer to a restoration that covers part of, or the entire, occlusal surface. However, the term onlay is commonly used in the literature and by clinicians to refer to a partial cuspal-coverage restoration, whereas the term overlay is used to refer to a full cuspal-coverage restoration. Other terms are found in literature for the adhesive cuspal coverage restorations, such as additional overlay, occlusal-veneer (overlay-veneer) and long-wrap overlay.[41] However, they are basically referring to adhesive overlays with various preparation designs to accommodate different clinical situations. For example, an occlusal-veneer (overlay-veneer) is an adhesive overlay which covers the occlusal surface and extends to the entire buccal surface for esthetic reasons.

Adhesive indirect restorations have the advantage of providing cuspal coverage, while preserving the maximum amount of tooth structure.[7] Because different adhesive overlay designs were suggested in literature, the design which conserves the maximum amount of tooth structure, without compromising the predictability or the esthetic outcome of the restoration, should be selected.[1],[42],[43]

There are different materials available for adhesive overlays, such as gold, composite resin, and ceramic materials. The adhesive gold overlays are minimally invasive indirect restorations, which offer the advantage of being biologically conservative of the tooth tissue.[44] The gold overlays were reported to have 89% survival rate over 5 years.[45] However, patients might object to the metal color, especially if the tooth lies in the esthetic zone of the patient.

The indirect resin composite overlay offers a biologically conservative and esthetic option. However, its clinical performance in the posterior dentition is still questionable.[46] A failure rate of 21% over 3 years was reported when used in posterior teeth in parafunctional patients.[47] However, more recent studies are reporting more favorable results.[48],[49],[50] The choice between a direct or indirect composite resin restoration can be affected by various factors such as the size of the restoration, cost, number of visits, number of restorations, and the operator's skill in building large composite resin restorations.[51] However, both treatment options were shown to perform similarly in a 5-year randomized controlled trial.[49]

Indirect ceramic restorations are considered an excellent restorative option for patients with high esthetic demands.[52] Compared to a conventional full-coverage crown, the indirect ceramic overlays preserve significant amounts of tooth structure.[7] Short- and long-term data for different ceramic materials used for adhesive overlays have reported excellent results as cusp-replacing restorations.[53],[54],[55] An etchable ceramic is used for adhesive ceramic overlays, and most commonly, the second generation of lithium disilicate ceramics (IPS e.max press, Ivoclar Vivadent, Schaan, Lichtenstein, Germany) is selected. It presents improved esthetic and physical properties compared to its predecessors.[56]

Examples of two moderately destructed teeth are presented in [Figure 2]a.[3] Assessment of the first and second mandibular molars revealed ETT with DO and MO cavities, respectively. Some of the remaining axial wall thicknesses were found to be <2 mm. There were no lateral forces on the teeth, and the patient had no parafunctional habits. These teeth can be managed through indirect adhesive ceramic overlays [Figure 2]b and [Figure 2]c.{Figure 2}

Severely destructed teeth

These teeth have suffered considerable amount of tooth structure loss. In addition to the necessity of cuspal coverage, such teeth usually require some sort of intraradicular retention to help retain the restoration.[57] Restoring such teeth with the mechanical methods will be through metal post, core, and full-coverage crowns.[21] The Nayyar technique followed by a full-coverage crown could also be used. In this technique, the restorative core material fills the pulp chamber and extends 2–3 mm into the coronal root canals.[58] Both of these treatment options will have better longevity and predictability if enough tooth structure was available to provide a ferrule.[59] In the absence of adequate tooth structure, clinical crown-lengthening procedure might be needed to obtain sufficient tooth structure to provide the necessary ferrule effect.[60] These conventional treatment options have been shown to be reliable clinically; however, they are not without a biological cost.[5] The full-coverage restoration leads to removal of significant amount of tooth structure, which is already scarce in such cases. In addition, such treatments are usually associated with an increase in the cost and time of treatment.[1]

The management of severely destructed ETT using the adhesive methods could be through the use of fiber post, core, and partial- or full-coverage crowns. The fiber posts unlike the metal posts depend on adhesion to the root dentine for its retention and have similar modulus of elasticity to that of dentine. They have been reported to decrease the incidence of catastrophic failures because their failure mode does not usually lead to a root fracture.[61] This is in contrast to metal posts, in which root fractures are more common.[62],[63] Therefore, the use of fiber posts is associated with more favorable types of failure and a higher chance of keeping the teeth restorable following failure.[64],[65],[66],[67]

The management of severely destructed ETT using adhesive methods could also be through the use of endocrowns. This treatment modality was originally referred to as the mono-block porcelain technique by Pissis.[68] Later on, the term Endocrown was introduced by Bindl and Mörmann.[69]

Multiple definitions of endocrowns have been suggested; however, there are currently no consensus in literature about their definition.[70] An endocrown is basically a type of restoration for ETT that consists of a core and a crown as a single unit, and extends into the pulp chamber.[68],[69] Retention is mainly obtained through adhesive resin cement (micro-mechanical retention). Extra retention and stability is provided through the pulp chamber's axial walls (macro-mechanical retention).[71] Consequently, materials with the capability of bonding through resin cement to the tooth structure have been selected for use in endocrowns such as glass ceramic materials (feldspathic ceramic) and, more recently, lithium disilicate ceramic and computer-aided design-computer-aided manufacturing composite materials.[70],[72]

Although less commonly used compared to other treatment options, the unique design of endocrowns provides this type of restoration with many clinical advantages. It has a conservative preparation design which preserves maximum amount of tooth structure. It avoids the need for a post, which would reduce the risk of vertical root fracture and incidental root perforations.[63],[73] Unlike the conventional post, core, and crown system, the endocrown does not need 1–2 mm of supragingival sound tooth structure to provide a ferrule. This will reduce the need for clinical crown-lengthening procedure and its associated disadvantages, such as the extra cost and time, the increased morbidity, the unnecessary bone removal from the adjacent teeth, and the possibility of loss of interdental papilla. Consequently, the use of endocrowns will generally decrease the number of visits and the cost of treatment.[1]

The endocrown restorations have recently been reported in a systematic review with favorable results:[74] three clinical trials and five in vitro studies were included, and a meta-analysis was performed. The clinical trials reported a success rate varying from 94% to 100% for endocrowns,[69],[75],[76] and the meta-analysis of the in vitro studies revealed no statistically significant differences in their survival compared to conventional treatments in posterior teeth.[74] In a more recent retrospective study which assessed 99 endocrowns up to 10 years with a mean observational period of 3.7 years, the survival and success rates of endocrowns were 99.0% and 89.9%, respectively, whereas the corresponding 10-year Kaplan–Meier-estimated survival and success rates were 98.8% and 54.9%, respectively. The main failures reported were periodontal disease, debonding, minor chipping, recurrent caries, and major fractures.[70]

Even though endocrowns have been reported consistently in literature to provide the molar teeth with good survival and success rates, they do not seem to be as consistent for premolar teeth. Bindl et al.[77] reported a higher failure rate of endocrowns for premolars than for molars, whereas Belleflamme et al. reported no difference in endocrown survival rates for premolars and molars.[70] This lack of consistency could be due to the fact that premolars have less bonding surface than molars, and that premolars have a big crown height-to-crown base ratio, which might cause occlusal forces to apply higher leverage on them compared to molars.[63],[77] In addition, premolars are generally more likely to be subjected to lateral forces during mastication than molars.[63] Therefore, an endocrown for premolar teeth needs to be further tested before it can be recommended with confidence, and a fiber post–core–crown could be considered the best treatment option available for the severely destructed premolar teeth.[64] A fiber post and core system has been recommended for the management of maxillary and mandibular premolar teeth in many studies.[64],[65],[78]

An example of a severely destructed molar is presented in [Figure 3]a. Assessment of this first mandibular molar revealed an ETT with tooth structure loss beyond an MOD cavity. There were no lateral forces on the tooth, and the patient had no parafunctional habits. This tooth was managed adhesively through an endocrown [Figure 3]b, [Figure 3]c, [Figure 3]d, [Figure 3]e. This will avoid the need for a post and core, avoid the need for clinical crown-lengthening procedure to provide a ferrule effect, and avoid further reduction of the remaining axial wall thickness.{Figure 3}

A flowchart of the protocol suggested in this article is presented in [Figure 4]. The protocol includes assessing the severity of tooth structure loss and assigning it to one of the three categories, followed by selecting the most conservative appropriate treatment option while keeping the key modifying factors in mind.{Figure 4}

 Conclusions



Minimally destructed ETT (teeth with an occlusal cavity or an MO/DO cavity with thick axial walls [≥2 mm]) could be restored using intracoronal composite resin restorationsModerately destructed ETT (teeth with an MO/DO cavity with thin axial walls [<2 mm] or an MOD cavity) could be restored using adhesive onlays/overlaysSeverely destructed ETT (teeth with structure loss beyond an MOD cavity) could be restored using fiber post–core–crown or endocrownsModifying factors (bruxism, lateral occlusal forces, or < 2 proximal contacts) should be taken into consideration during the decision-making process.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Rocca GT, Krejci I. Crown and post-free adhesive restorations for endodontically treated posterior teeth: From direct composite to endocrowns. Eur J Esthet Dent 2013;8:156-79.
2Zarow M, Devoto W, Saracinelli M. Reconstruction of endodontically treated posterior teeth – With or without post? Guidelines for the dental practitioner. Eur J Esthet Dent 2009;4:312-27.
3Tjan AH, Munoz Viveros CA, Valencia Rave GM. Tensile dislodgement of composite/amalgam cores: Dentin adhesives vs. mechanical retention. J Dent Res 1997;76:1355.
4Van Meerbeek B, Vargas M, Inoue S, Yoshida Y, Peumans M, Lambrechts P, et al. Adhesives and cements to promote preservation dentistry. Oper Dent 2001;26:119-144.
5Sorensen JA, Martinoff JT. Intracoronal reinforcement and coronal coverage: A study of endodontically treated teeth. J Prosthet Dent 1984;51:780-4.
6Aquilino SA, Caplan DJ. Relationship between crown placement and the survival of endodontically treated teeth. J Prosthet Dent 2002;87:256-63.
7Edelhoff D, Sorensen JA. Tooth structure removal associated with various preparation designs for anterior teeth. J Prosthet Dent 2002;87:503-9.
8Rocca GT, Rizcalla N, Krejci I, Dietschi D. Evidence-based concepts and procedures for bonded inlays and onlays. Part II. Guidelines for cavity preparation and restoration fabrication. Int J Esthet Dent 2015;10:392-413.
9Mondelli J, Steagall L, Ishikiriama A, de Lima Navarro MF, Soares FB. Fracture strength of human teeth with cavity preparations. J Prosthet Dent 1980;43:419-22.
10Larson TD, Douglas WH, Geistfeld RE. Effect of prepared cavities on the strength of teeth. Oper Dent 1981;6:2-5.
11Seltzer S, Bender IB. The Dental Pulp: Biologic Consideration in Dental Procedures. 2nd ed. Philadelphia: JB Lippincott; 1975.
12Silness J. Periodontal conditions in patients treated with dental bridges. J Periodontal Res 1970;5:60-8.
13Carvalho MA, Lazari PC, Gresnigt M, Del Bel Cury AA, Magne P. Current options concerning the endodontically-treated teeth restoration with the adhesive approach. Braz Oral Res 2018;32:e74.
14Shugars DA, Hayden WJ Jr., Crall JJ, Scurria MS. Variation in the use of crowns and their alternatives. J Dent Educ 1997;61:22-8.
15Chang CY, Kuo JS, Lin YS, Chang YH. Fracture resistance and failure modes of CEREC endo-crowns and conventional post and core-supported CEREC crowns. J Dent Sci 2009;4:110-7.
16Reeh ES, Messer HH, Douglas WH. Reduction in tooth stiffness as a result of endodontic and restorative procedures. J Endod 1989;15:512-6.
17Nagasiri R, Chitmongkolsuk S. Long-term survival of endodontically treated molars without crown coverage: A retrospective cohort study. J Prosthet Dent 2005;93:164-70.
18Mannocci F, Bertelli E, Sherriff M, Watson TF, Ford TR. Three-year clinical comparison of survival of endodontically treated teeth restored with either full cast coverage or with direct composite restoration. J Prosthet Dent 2002;88:297-301.
19Ng YL, Mann V, Gulabivala K. Tooth survival following non-surgical root canal treatment: A systematic review of the literature. Int Endod J 2010;43:171-89.
20Sequeira-Byron P, Fedorowicz Z, Carter B, Nasser M, Alrowaili EF. Single crowns versus conventional fillings for the restoration of root-filled teeth. Cochrane Database Syst Rev 2015;9:CD009109.
21Smith CT, Schuman N. Restoration of endodontically treated teeth: A guide for the restorative dentist. Quintessence Int 1997;28:457-62.
22Afrashtehfar KI, Tamimi F. An online tool that provides access to evidence-based literature on dental restorations: www.crownorfill.com. J Prosthet Dent 2017;118:696-7.
23Seow LL, Toh CG, Wilson NH. Remaining tooth structure associated with various preparation designs for the endodontically treated maxillary second premolar. Eur J Prosthodont Restor Dent 2005;13:57-64.
24Faria AC, Rodrigues RC, de Almeida Antunes RP, de Mattos Mda G, Ribeiro RF. Endodontically treated teeth: Characteristics and considerations to restore them. J Prosthodont Res 2011;55:69-74.
25González-López S, De Haro-Gasquet F, Vílchez-Díaz MA, Ceballos L, Bravo M. Effect of restorative procedures and occlusal loading on cuspal deflection. Oper Dent 2006;31:33-8.
26Linn J, Messer HH. Effect of restorative procedures on the strength of endodontically treated molars. J Endod 1994;20:479-85.
27Shahrbaf S, Mirzakouchaki B, Oskoui SS, Kahnamoui MA. The effect of marginal ridge thickness on the fracture resistance of endodontically-treated, composite restored maxillary premolars. Oper Dent 2007;32:285-90.
28Panitvisai P, Messer HH. Cuspal deflection in molars in relation to endodontic and restorative procedures. J Endod 1995;21:57-61.
29Reagan SE, Schwandt NW, Duncanson MG Jr. Fracture resistance of wide-isthmus mesio-occlusodistal preparations with and without amalgam cuspal coverage. Quintessence Int 1989;20:469-72.
30Scotti N, Rota R, Scansetti M, Paolino DS, Chiandussi G, Pasqualini D, et al. Influence of adhesive techniques on fracture resistance of endodontically treated premolars with various residual wall thicknesses. J Prosthet Dent 2013;110:376-82.
31Steele A, Johnson BR.In vitro fracture strength of endodontically treated premolars. J Endod 1999;25:6-8.
32Smales RJ, Hawthorne WS. Long-term survival of extensive amalgams and posterior crowns. J Dent 1997;25:225-7.
33Martin JA, Bader JD. Five-year treatment outcomes for teeth with large amalgams and crowns. Oper Dent 1997;22:72-8.
34Abu-Awwad M. Dentists' decisions regarding the need for cuspal coverage for endodontically treated and vital posterior teeth. Clin Exp Dent Res 2019;5:326-35.
35Dammaschke T, Nykiel K, Sagheri D, Schäfer E. Influence of coronal restorations on the fracture resistance of root canal-treated premolar and molar teeth: A retrospective study. Aust Endod J 2013;39:48-56.
36Nishigawa K, Bando E, Nakano M. Quantitative study of bite force during sleep associated bruxism. J Oral Rehabil 2001;28:485-91.
37Loney RW, Moulding MB, Ritsco RG. The effect of load angulation on fracture resistance of teeth restored with cast post and cores and crowns. Int J Prosthodont 1995;8:247-51.
38Zhu J, Rong Q, Wang X, Gao X. Influence of remaining tooth structure and restorative material type on stress distribution in endodontically treated maxillary premolars: A finite element analysis. J Prosthet Dent 2017;117:646-55.
39Krejci I, Duc O, Dietschi D, de Campos E. Marginal adaptation, retention and fracture resistance of adhesive composite restorations on devital teeth with and without posts. Oper Dent 2003;28:127-35.
40Costa LC, Pegoraro LF, Bonfante G. Influence of different metal restorations bonded with resin on fracture resistance of endodontically treated maxillary premolars. J Prosthet Dent 1997;77:365-9.
41Veneziani M. Posterior indirect adhesive restorations: Updated indications and the morphology driven Preparation technique. Int J Esthet Dent 2017;12:204-30.
42Politano G, Fabianelli A, Papacchini F, Cerutti A. The use of bonded partial ceramic restorations to recover heavily compromised teeth. Int J Esthet Dent Autu; 11:314-36.
43Ferraris F. Posterior indirect adhesive restorations (PIAR): Preparation designs and adhesthetics clinical protocol. Int J Esthet Dent 2017;12:482-502.
44Banerji S, Mehta SB, Millar BJ. Cracked tooth syndrome. Part 2: Restorative options for the management of cracked tooth syndrome. Br Dent J 2010;208:503-14.
45Chana H, Kelleher M, Briggs P, Hooper R. Clinical evaluation of resin-bonded gold alloy veneers. J Prosthet Dent 2000;83:294-300.
46Magne P, Belser UC. Porcelain versus composite inlays/onlays: Effects of mechanical loads on stress distribution, adhesion, and crown flexure. Int J Periodontics Restorative Dent 2003;23:543-55.
47Bartlett D, Sundaram G. An up to 3-year randomized clinical study comparing indirect and direct resin composites used to restore worn posterior teeth. Int J Prosthodont 2006;19:613-7.
48Magne P, Knezevic A. Simulated fatigue resistance of composite resin versus porcelain CAD/CAM overlay restorations on endodontically treated molars. Quintessence Int 2009;40:125-33.
49Fennis WM, Kuijs RH, Roeters FJ, Creugers NH, Kreulen CM. Randomized control trial of composite cuspal restorations: Five-year results. J Dent Res 2014;93:36-41.
50Deliperi S, Bardwell DN. Clinical evaluation of direct cuspal coverage with posterior composite resin restorations. J Esthet Restor Dent 2006;18:256-65.
51Plotino G, Buono L, Grande NM, Lamorgese V, Somma F. Fracture resistance of endodontically treated molars restored with extensive composite resin restorations. J Prosthet Dent 2008;99:225-32.
52Griggs JA. Recent advances in materials for all-ceramic restorations. Dent Clin North Am 2007;51:713-27, viii.
53Otto T, De Nisco S. Computer-aided direct ceramic restorations: A 10-year prospective clinical study of cerec CAD/CAM inlays and onlays. Int J Prosthodont 2002;15:122-8.
54Felden A, Schmalz G, Hiller KA. Retrospective clinical study and survival analysis on partial ceramic crowns: Results up to 7 years. Clin Oral Investig 2000;4:199-205.
55Archibald JJ, Santos GC Jr., Moraes Coelho Santos MJ. Retrospective clinical evaluation of ceramic onlays placed by dental students. J Prosthet Dent 2018;119:743-80.
56Fasbinder DJ. Materials for chairside CAD/CAM restorations. Compend Contin Educ Dent 2010;31:702-4, 706, 708-9.
57Afrashtehfar KI, Ahmadi M, Emami E, Abi-Nader S, Tamimi F. Failure of single-unit restorations on root filled posterior teeth: A systematic review. Int Endod J 2017;50:951-66.
58Nayyar A, Walton RE, Leonard LA. An amalgam coronal-radicular dowel and core technique for endodontically treated posterior teeth. J Prosthet Dent 1980;43:511-5.
59Sorensen JA, Engelman MJ. Ferrule design and fracture resistance of endodontically treated teeth. J Prosthet Dent 1990;63:529-36.
60Stankiewicz NR, Wilson PR. The ferrule effect: A literature review. Int Endod J 2002;35:575-81.
61Ferrari M, Mannocci F. A 'one-bottle' adhesive system for bonding a fibre post into a root canal: An SEM evaluation of the post-resin interface. Int Endod J 2000;33:397-400.
62Ferrari M, Vichi A, García-Godoy F. Clinical evaluation of fiber-reinforced epoxy resin posts and cast post and cores. Am J Dent 2000;13:15B-8B.
63Schwartz RS, Robbins JW. Post placement and restoration of endodontically treated teeth: A literature review. J Endod 2004;30:289-301.
64Salameh Z, Sorrentino R, Papacchini F, Ounsi HF, Tashkandi E, Goracci C, et al. Fracture resistance and failure patterns of endodontically treated mandibular molars restored using resin composite with or without translucent glass fiber posts. J Endod 2006;32:752-5.
65Soares CJ, Soares PV, de Freitas Santos-Filho PC, Castro CG, Magalhaes D, Versluis A. The influence of cavity design and glass fiber posts on biomechanical behavior of endodontically treated premolars. J Endod 2008;34:1015-9.
66Mannocci F, Qualtrough AJ, Worthington HV, Watson TF, Pitt Ford TR. Randomized clinical comparison of endodontically treated teeth restored with amalgam or with fiber posts and resin composite: Five-year results. Oper Dent 2005;30:9-15.
67Ferrari M, Vichi A, Mannocci F, Mason PN. Retrospective study of the clinical performance of fiber posts. Am J Dent 2000;13:9B-13B.
68Pissis P. Fabrication of a metal-free ceramic restoration utilizing the monobloc technique. Pract Periodontics Aesthet Dent 1995;7:83-94.
69Bindl A, Mörmann WH. Clinical evaluation of adhesively placed cerec endo-crowns after 2 years – Preliminary results. J Adhes Dent 1999;1:255-65.
70Belleflamme MM, Geerts SO, Louwette MM, Grenade CF, Vanheusden AJ, Mainjot AK. No post-no core approach to restore severely damaged posterior teeth: An up to 10-year retrospective study of documented endocrown cases. J Dent 2017;63:1-7.
71Reich SM, Wichmann M, Rinne H, Shortall A. Clinical performance of large, all-ceramic CAD/CAM-generated restorations after three years: A pilot study. J Am Dent Assoc 2004;135:605-12.
72Bernhart J, Bräuning A, Altenburger MJ, Wrbas KT. Cerec3D endocrowns – Two-year clinical examination of CAD/CAM crowns for restoring endodontically treated molars. Int J Comput Dent 2010;13:141-54.
73Ferrari M, Vichi A, Grandini S. Efficacy of different adhesive techniques on bonding to root canal walls: An SEM investigation. Dent Mater 2001;17:422-9.
74Sedrez-Porto JA, Rosa WL, da Silva AF, Münchow EA, Pereira-Cenci T. Endocrown restorations: A systematic review and meta-analysis. J Dent 2016;52:8-14.
75Otto T. Computer-aided direct all-ceramic crowns: Preliminary 1-year results of a prospective clinical study. Int J Periodontics Restorative Dent 2004;24:446-55.
76Decerle N, Bessadet M, Munoz-Sanchez ML, Eschevins C, Veyrune J, Nicolas E. Evaluation of cerec endocrowns: A preliminary cohort study. Eur J Prosthodont Restor Dent 2014;22:89-95.
77Bindl A, Richter B, Mörmann WH. Survival of ceramic computer-aided design/manufacturing crowns bonded to preparations with reduced macroretention geometry. Int J Prosthodont 2005;18:219-24.
78Forberger N, Göhring TN. Influence of the type of post and core on in vitro marginal continuity, fracture resistance, and fracture mode of lithia disilicate-based all-ceramic crowns. J Prosthet Dent 2008;100:264-73.