Prevalence and Associated Factors of Root Canal Treated Mandibular Anterior Teeth with and without Post Endodontic Crowns

Keywords

Mandibular Anteriors; Post Endodontic Restoration; Root Canal Treatment.

Introduction

A root filled tooth is unlike a vital tooth due to the effect of endodontic treatment. It is thought that root canal treatment leads to weakening of the remaining tooth structure as a result of various factors like changes in tooth architecture, changes in proprioception, changes in the properties of dentin [1]. The effects are the same for both anterior and posterior teeth as only the consequences vary depending on the anatomical structure and loading patterns. It has been stated that root canal therapy saves the tooth, whereas the restoration reinstates the tooth as a functional member of the masticatory system and also enhances the aesthetic appearance [2]. In order to accomplish this goal, the restorative procedure should be primarily concerned with prevention of tooth fracture. After completion of the endodontic treatment, depending on the remaining natural tooth structure, placement of the coronal seal/crown is indicated [3]. This prevents contamination and microleakage thus enforcing adequate stability and structural durability to the root canal treated tooth. Hence a temporary or permanent restoration should be placed after root canal therapy [4, 5].

Over the years controversies over the variety of materials being used for the reinforcement of the endodontically treated teeth, especially over the use of crowns have been studied [6]. If an endodontically treated anterior tooth is to receive a crown, a post often is indicated. In most cases, the remaining coronal portion is quite thin after it has received root canal treatment and has been prepared for a crown [7]. Even though the successful root canal treatment promises to enhance the lifespan of the treated tooth in both structural and aesthetic aspects, there are few studies that suggest that the tooth with root canal procedures are not restored with permanent restoration after that root canal treatment are thought to be about two to four times weaker [8].

The presence of the remaining coronal tooth structure and the functional requirement of the teeth determine whether an anterior tooth requires a post [9]. A study done by Kruler CM et al showed that coronal coverage did significantly improve the rate of clinical success for anterior teeth [10]. When there is no functional (or) aesthetic requirement for a full coverage restoration, a post is not indicated. If a full coverage restoration is chosen however, the decision to place a post is dedicated by the amount of coronal remaining tooth structure present after the crown preparation is completed and the functional requirement of the restored tooth [11].

A systematic review done by Stavropoulou et al showed that root canal treated teeth covered with crowns have a higher long term survival rate than root canal treated teeth without crown coverage [12]. It is also suggested that saving the natural tooth requires both excellent endodontic treatment along with follow up of a restorative treatment in order to increase the longevity of the tooth [13]. The restoration of the endodontically treated teeth is a topic that is extensively studied and yet remains controversial from many perspectives. The aim of this study was to evaluate the frequency of root canal treated mandibular anteriors not treated with post endodontic full veneer restoration in patients under 25 years of age in our institution.

Materials and Methods

Study Setting

The current study is an institutional based retrospective study performed at a private dental college.

Ethical approval

The necessary approvals were obtained from the Institutional Ethical committee - SDC/SIHEC/2020/DIASDATA/0619-0320.

Data Collection and Tabulation

All the case records and treatment records were obtained from the patient management software and the data collected was cross verified by an examiner to avoid any missing case records. A total of 885 case sheets were verified for root canal treatment in relation to mandibular anteriors. Out of 885 subjects, 50 subjects who underwent root canal treatment in relation to mandibular anteriors under 25 years of age were chosen carefully verifying the data and history. All the data collected was formatted and tabulated using Microsoft Excel ( Version - 2020). The dependent variable was root canal treated mandibular anteriors from 18 to 25 years of age group.

Inclusion criteria

The Inclusion criteria included patients undergoing root canal treatment in relation to mandibular anteriors from 18 to 25 years of age group.

Exclusion criteria

The exclusion criteria was missing or incomplete data and it also eliminated cases that were not approved by the concerned faculty in the hospital.

Statistical analysis

The statistical analysis was performed using IBM SPSS (Version - 24). Chi square test was done, to associate between gender and post endodontic crown for prognosis of the root canal treated teeth.

Results and Discussion

In the present study which included 50 patients, 76% (38) males and 24% (12) females have undergone root canal treatment (Figure 1). The most common teeth for root canal treatment was found to be 41 (25.77%) followed by 31 (22.68%), 42 (21.65%), 32 (15.46%) and the least being both 33 and 43 (7.22%) (Figure 2). Out of 97 teeth which had undergone root canal treatment, post endodontic crown had been fabricated and inserted in 43 mandibular anteriors (44.3%) and the remaining 54 (55.7%) mandibular anteriors did not receive endodontic crowns (Figure 3). 38% of males and 10% of females had received crowns, 38% of males and 14% of females did not receive crowns (Figure 4) No significant association was seen between gender and practice of post endodontic crowns. Chi-square test was performed and was found to be statistically not significant (p = 0.614; p > 0.05). 12.37% of root canal treated teeth in relation to 31 and 41 had received crowns, which was followed by 9.28% in 42, 7.22% in 32, 2.06% in 43 and the least being 1.03% in 33. 13.40% of root canal treated teeth in relation to 41 did not receive crowns, which was followed by 12.37% in 42, 10.31% in 31, 8.25% in 32, 6.19% in 33 and the least being 5.15% in 43. Results show the highest incidence of post endodontic crown was seen in both 31 and 41 with 12.37% compared to other teeth (Figure 5) Chi-square test was performed and was found to be statistically not significant (p = 0.496; p > 0.05).

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Teeth with significant remaining natural tooth structure after endodontic treatment must be considered differently from those with extensive loss of tooth structure. When sufficient tooth structure is present to retain the core and crown, in such condition posts are not recommended. Success of endodontic treatment depends on the quality of the coronal restoration, which should provide the functional marginal seal and protect the remaining tooth structure [11, 12, 14]. In a study conducted by Sedgley et al, stated that anterior teeth must resist lateral and shearing types of forces and pulp chambers are too small for a post, depending on the remaining coronal structure, the placement of a post is decided [15]. In a study conducted by Naoum and Chandler [16], they found that there was no difference in the reinforcement of maxillary central incisors and mandibular cuspids without post.

One of the causes of failure of endodontic treatments is an incomplete instrumentation or filling of all root canals. There are many factors which influence the fracture of an endodontically treated tooth. The risk of tooth fracture increases from the beginning of endodontic therapy, so effective temporary and final restorations are given . The primary concern is that of resistance form as the tooth must be able to resist both vertical and horizontal forces [17].

In the recent years prefabricated posts have become very popular. Overall fixed dental prosthesis bridges have significantly lower long term survival rates than teeth retained through RCT and restoration or those replaced using single implant crowns [18]. The amount of remaining tooth structure is more important than any restorative strategy and the risks due to dental caries and periodontal disease must always be recognised in order to have a good prognosis.

The limitations of the present study include that it is single centered and has geographic limitations. The medical status of the patient was not considered with a sample size limitation as well. Further multi centered studies should be carried out with a larger sample size to create a standardized protocol for root canal therapy and post endodontic crowns. Previously our team had conducted numerous clinical trials [19-21], in vitro studies [22-26] and surveyed [27, 28] and reviewed various aspects of endodontics and conservative dentistry over the past five years [29-33]. Now we are focusing on retrospective studies, the idea for which has stemmed from the current interest in our community.

Conclusion

Within the limitations of the study, the prevalence of root canal treated mandibular anteriors with post endodontic crowns was 44.3%, mandibular central incisors more commonly underwent post endodontic crown compared to other teeth and the association between gender and the practice of post endodontic crowns was not significant but males had undergone more number of crowns than females in the age group of 18 to 25 years. Root canal treated mandibular anterior teeth with sound tooth structure can be managed without full coverage restoration.

Author Contribution

Roghith Kannan carried out the retrospective study, collection and analysis of data and drafted the manuscript. Dr Adimulapu Hima Sandeep designed the study and participated in data analysis verification and drafting the manuscript. Dr Revathi D aided in supervision and appraisal of the manuscript.

Acknowledgements

We thank Saveetha Dental College and Hospitals, Chennai for access to the retrospective data.