|Year : 2022 | Volume
| Issue : 2 | Page : 130-138
A clinical and radiographic comparative evaluation of treatment outcome of different fiber post systems with conventional cast metal post and core system
Sourabh Sharma1, Sonali Sharma1, Balakrishnan Jayan2, Anubhav Chakrabarty1
1 Department of Conservative Dentistry and Endodontics, Army Dental Centre (Research and Referral), New Delhi, India
2 Army Dental Centre (Research and Referral), New Delhi, India
|Date of Submission||27-May-2021|
|Date of Decision||08-Dec-2021|
|Date of Acceptance||14-Jul-2022|
|Date of Web Publication||21-Dec-2022|
Department of Conservative Dentistry and Endodontics, Army Dental Centre (Research and Referral), New Delhi
Source of Support: None, Conflict of Interest: None
Aim: To compare clinically and radiographically the treatment outcome of different post and core systems.
Methodology: Patients with nonvital anterior teeth with middle or cervical third crown fracture and those fulfilling the inclusion and exclusion criteria were enrolled in the study. After clinical and radiological examination and confirmation of eligibility, the selected cases were randomly divided into three groups: Group A, cast metal post and core system (control group); Group B, glass fiber-reinforced resin post and core system (test group); and Group C, bundle glass fiber-reinforced resin post and core system (test group).
Results: Group A (control group, cast metal post) provided the maximum number of failed cases with 1 sinus formation, 2 root fractures, 3 periapical pathology, 5 post adaptation failures, and 3 esthetic failures. In Group B (glass fiber post), there was 1 failed case due to debonding, 1 due to core fracture, and 3 were post adaptation failure. Minimum numbers of failures were seen in Group C (bundled glass fiber post) with only 1 post adaptation failure.
Conclusion: The Bundle glass fiber reinforced resin post and core system can be a reliable alternative due to various advantages as
- Can adapt any root canal morphology while preserving remaining dentine thickness
- Provides homogenous reinforcement to the entire core buildup
- Modulus of elasticity similar to that of dentin provides elevated shock resistance, shock absorption and prevents root fracture
- Excellent esthetic property.
Keywords: Bundle glass fiber post, modulus of elasticity, Remaining dentin thickness
|How to cite this article:|
Sharma S, Sharma S, Jayan B, Chakrabarty A. A clinical and radiographic comparative evaluation of treatment outcome of different fiber post systems with conventional cast metal post and core system. J Dent Def Sect. 2022;16:130-8
|How to cite this URL:|
Sharma S, Sharma S, Jayan B, Chakrabarty A. A clinical and radiographic comparative evaluation of treatment outcome of different fiber post systems with conventional cast metal post and core system. J Dent Def Sect. [serial online] 2022 [cited 2023 Jan 31];16:130-8. Available from: http://www.journaldds.org/text.asp?2022/16/2/130/364517
| Introduction|| |
Endodontically treated teeth have demonstrated an increased risk of fracture when compared to vital teeth. Access preparations can result in increased cuspal deviation during function and can lead to cusp fracture and microleakage at the margins of the restoration. In most of the endodontically treated teeth, there is an associated loss of tooth structure because of the sequelae of dental caries or restoration. This makes it essential to have a postendodontic restoration that augments the structural integrity and thereby enhances the prognosis of endodontically treated teeth exposed to heavy masticatory loading forces. Thus, to reinforce postendodontic restoration, some anchorage within teeth must be made, which is gained by a rigid structure which is known as a post.
A post or dowel is a rigid or a relatively rigid, restorative material placed in the prepared root canal. A post is required in endodontically treated teeth with insufficient sound tooth structure remaining above the periodontal attachment to retain a coronal restoration. Hence, the primary function of a post is to aid in retaining a core to restore lost tooth structure for retention of restoration and not to provide strength or resistance to fracture. Endodontic posts have been classified as per shape, method of fabrication, type of material, flexibility, and esthetics.
Traditionally, cast metal posts were used for rehabilitating grossly mutilated endodontically treated teeth. Fabrication of these posts and core is laboratory based and is time-consuming and led to inherent casting errors and defects. Prefabricated metallic posts were introduced to reduce treatment time and to overcome casting defects. Metallic posts have a higher elastic modulus than fiber posts and were a major reason for root fracture and mechanical and biological failure. Stress distribution studies have inferred that metallic posts cause a higher amount of catastrophic root fractures by transferring high stress to the tooth structure.,
When two or more components are placed in contact with one another, the components and interfaces created will be subjected to considerable clinical and functional demands. Components having a higher modulus of elasticity (cast post/core) will transfer functional stresses to the components having a lower modulus of elasticity (dentin) and ultimately result in endodontic or restorative failure. When all components have a similar modulus of elasticity, there is a uniform stress distribution and lower interfacial stress and failure. This phenomenon has been coined as “monobloc,” where all components of a tooth restoration have similar elastic modulus to dentin to allow the components to move, flex, and stress as one assembly. Owing to greater similarity in elastic properties with dentine, fiber-reinforced composite posts allow a relatively uniform stress distribution to the tooth and surrounding tissues, thus yielding a protective effect against root fracture. Other advantages of fiber posts include simplifying the post endodontic restoration procedure in comparison with the use of cast posts, by eliminating the laboratory step. In addition, in case endodontic retreatment is inescapable, fiber posts are relatively easy to remove by boring through the middle of the post with an ultrasonic or a rotary instrument., The prefabricated posts could not record and replicate the exact internal post space and requires a specific corresponding drill to create the desired post space.
A recently developed bundle glass fiber-reinforced composite post system consists of a bundle of fine individual posts of 0.3 mm diameter in varying numbers; all are encased in a hollow plastic sleeve from one terminal end. Thus, on placement in the root canal and removal of sleeve, the fibers fan out and occupy and take the shape of the prepared internal morphology of the root canal. In the case of narrow canals, one or two fine glass fibers can be removed from the bundle to an overall reduction in diameter of a bundle glass fiber post, without the need of the specific drill. This system is, thus, indicated in teeth with atypical root canal anatomies and pronounced conicity. The modulus of elasticity is like that of dentin, i.e., 31.5 GPa. It is characterized by high radiopacity (408% Al) as well as high flexural strength and fracture resistance.
Thus, in this study, we have compared the clinical and radiological performance of newer bundle glass fiber-based post and core systems with traditional post and core systems.
To compare clinically and radiographically the treatment outcome of different post and core systems.
- To assess the clinical parameters such as core fracture, debonding, crown fracture, and periodontal status for each post and core system
- To assess the radiographic parameters such as root fracture, post fracture, debonding, and periapical status for each post and core system
- To compare and evaluate the clinical and radiographical performance of all post and core systems at the end of 3 months, 6 months, and 9 months.
The clinical and radiographic treatment outcome of newer fiber post systems is unsatisfactory as compared to conventional cast metal post and core systems.
New-generation glass fiber post and core systems exhibit better treatment outcomes than traditional custom-made cast metal posts and core systems.
| Methodology|| |
A clinical study was carried out in the Department of Conservative Dentistry and Endodontics, Army Dental Centre (Research and Referral). The study was approved by the institutional ethics committee, and informed consent was taken from every patient participating in the study.
The sample size had been calculated by assuming at the most 5% risk, with a minimum 80% power and 5% significance level (significant at 95% confidence level, Z = 1.96). However, we also referred to a similar study/data to get an idea about the nature of the outcomes of the data. We had assumed a 95% confidence level, 0.90 probability of success, and a margin of error (confidence interval) of ±13%. The calculation of sample size with the above assumptions had been 21 in each group. Since follow-up was also there in the study, we considered a sample of 25 cases in each group and hence overall 75 cases for the study.
The formula used for the same is as follows:
Sample size formula = (Z2 × P(1 − P)/e2
Source of data
Adult patients of either sex, aged above 18 years with nonvital, discolored, fractured, maxillary anterior teeth indicated for post and core restorations, referred to the Department of Conservative Dentistry and Endodontics, Army Dental Centre (Research and Referral) were included in the study.
Criteria for the selection of patients
- Grossly mutilated maxillary anterior teeth indicated for a root canal treatment
- Maxillary anterior teeth with cervical and middle third crown fracture
- Male and female patients aged 18 years and above with nonvital fractured maxillary anterior teeth
- Teeth with healthy periodontal status
- Teeth with adequate bone support
- Occlusion with sufficient overjet and overbite
- Teeth with complete root formation
- Teeth without anatomic variation
- Endodontically treated maxillary anterior teeth with cervical and middle third crown fracture
- Patients willing to give written informed consent
- Teeth with no sign of periapical pathology
- Nonvital discolored single-rooted maxillary anterior teeth with cervical and middle third crown fracture.
- Nonvital multirooted teeth
- Maxillary anterior, vital teeth with less than incisal third coronal fracture
- Patient aged <18 years
- Teeth with poor periodontal status
- Teeth with extensive loss of bone support
- Malocclusion with deep bite, edge-to-edge bite, and crossbite
- Teeth with a wide-open apex
- Teeth with variation in radicular anatomy
- Teeth with large persistent periapical lesion
- To prevent radiation hazard expectant mothers
- Root with Internal or external resorption
- A tooth with calcified canal or presence of pulp stones
- Patients not willing to give consent
- Patients with medical conditions due to which follow-up not possible.
Patients with nonvital anterior teeth with middle or cervical third crown fracture and those fulfilling the inclusion and exclusion criteria were enrolled in the study. After clinical and radiological examination and confirmation of eligibility, the selected cases were randomly divided into three groups:
- Group A: Cast metal post and core system (control group)
- Group B: Glass fiber-reinforced resin post and core system (test group)
- Group C: Bundle glass fiber-reinforced resin post and core system (test group).
The treatment procedure for all the groups and follow-up were carried by a single operator. Identical clinical and radiographic parameters were evaluated for all the groups, and the same was recorded. Periapical radiographs were taken using a digital radiography sensor positioner holder. This served as a baseline.
Follow-up at an interval of clinical and radiographic parameters that had been measured at baseline was measured postoperatively 3 months, 6 months, and 9 months after the treatment.
Treatment technique Group A (control group) (cast metal post and core system)
Based on the inclusion and exclusion criteria, 27 patients were selected.
Endodontic treatment was completed for all the involved teeth as per the standard procedure using gutta-percha/sealer as an obturating material/by lateral compaction technique. After 48 h of the endodontic treatment, the involved teeth were prepared for receiving the posts. Leaving 4–5 mm of gutta-percha in the apical third of the root canal, the post space preparation was done with the help of Peso Reamers and Gates–Glidden drills. Prepared post space was irrigated with normal saline to remove any debris. Canal was dried with paper points. The direct wax pattern was recorded and invested. The casting procedure was carried out in the induction casting machine. The custom-made post and core were then cemented in the root canal using glass ionomer luting cement (GC). Later, the ceramic crowns were fabricated and cemented.
Group B (test group) (glass fiber-reinforced resin post and core system)
Based on the inclusion and exclusion criteria, 26 patients were selected.
Endodontic treatment was completed for all the involved teeth as per the standard procedure using gutta-percha and sealer as an obturating material with lateral compaction technique. After 48 h from the endodontic treatment, the post space preparation was done with a corresponding drill provided with the prefabricated post kit, and the root canal space was prepared to leave at least 4–5 mm of gutta-percha apically. The system chosen was Rebilda Post glass fiber reinforced resin post and core system (VOCO, Germany) for post and core. Corresponding to the width of canal space, the Rebilda Post was selected. To confirm the width and position, the selected Rebilda Post was inserted into the prepared post space, and a radiograph was taken. After confirmation, the prepared space was rinsed with saline and dried with the help of a paper point. Silanation of the post was done with ceramic bond, allowed to act for 60 s and air-dried. For luting Rebilda Post, dual-cure adhesive (e.g., Futurabond U) following the respective instructions was used. Then, the core build-up composite (Rebilda DC, VOCO Germany) was filled into the canal using an application tip, and the selected Rebilda Post was inserted. Before polymerization, shorting of post according to desire length was done with the help of a diamond bur in the absence of water. Final polymerization was done with the help of a light cure gun. The composite was used as a core build-up material. The ceramic crowns were fabricated later and cemented.
Group C (test group) (bundle glass fiber-reinforced resin post and core system)
Based on the inclusion and exclusion criteria, 27 patients were selected.
Endodontic treatment was completed for all the involved teeth as per the standard procedure using gutta-percha and sealer as an obturating material with lateral compaction technique. After 48 h from the endodontic treatment, the post space preparation was done leaving at least 4–5 mm of gutta-percha apically. The system chosen was Rebilda Post GT-Bundle glass fiber-reinforced resin post and core system (VOCO, Cuxhaven, Germany) for post and core. Corresponding to the width of canal space, the Rebilda Post GT was selected. To confirm the width and position, the selected Rebilda Post GT was inserted into the prepared post space, and a radiograph was taken. After confirmation, the prepared space was rinsed with saline and dried with the help of a paper point. Silanation of ther post was done with ceramic bond, allowed to act for 60 s and air-dried. For luting Rebilda Post GT, dual-cure adhesive (e.g., Futurabond U) following the respective instructions was used. Then, the core build-up composite (Rebilda DC, VOCO Germany) was filled into the canal using an application tip, and the selected Rebilda Post GT was inserted. When holding the Rebilda Post GT in the canal, the sleeve was removed with the help of a tweezer, and flaring of individual fibers was done with the help of a spreader. This ensured more homogeneous reinforcement of the post cement. Final polymerization did with the help of a light-cured gun. After polymerization, shorting of post according to desire length was done with the help of a diamond bur in the absence of water. The composite was used as a core build-up material. The ceramic crowns were fabricated later and cemented.
The patient was recalled after 3 months, 6 months, and 9 months and was assessed on predetermined clinical and radiological parameters. Periapical radiographs were taken using a digital radiography sensor positioner holder.
The clinical parameters assessed
- Debonding at post core and tooth interfaces
- Core fracture
- Crown fracture
- Periodontal status
The radiological parameters assessed
- Root fracture
- Post fracture
- Periapical status
- Post adaptation in the root canal.
Statistical analysis was done using descriptive and inferential statistics using the Chi square test/Fisher's exact test for nominal/categorical data and one way analysis of variance followed by a post hoc test for multiple comparisons. A paired t-test to see the relative change concerning time was used. P < 0.05 was considered statistically significant at a 95% confidence level. The statistical IBM Crop. Released 2016. IBM SPSS Statistics for Windows,Version 24.0. Armonk, NY: IBM Corp was used in the analysis.
| Results|| |
Based on the inclusion and exclusion criteria, 80 participants were selected in the study and were randomly divided into three groups named Group A (control group, cast metal post), Group B (test group, glass fiber-reinforced resin post system), and Group C (test group, bundle glass fiber-reinforced resin post system). In all selected cases, primary endodontic treatment followed by post adaptation and core buildup and final prosthetic rehabilitation was done with the all-ceramic crown. The treated cases were evaluated clinically and radiographically at postoperative, 3 months, 6 months, and 9 months. The attrition rate was 5 patients in this study.
| Summary of Results|| |
Group A (control group, cast metal post) provided the maximum number of failed cases with 1 sinus formation, 2 root fractures, 3 periapical pathology [Graph 1], 5 post adaptation failures, and 3 esthetic failures. In Group B (glass fiber post), there was 1 failed case due to debonding, 1 due to core fracture, and 3 were post adaptation failure. Minimum numbers of failures were seen in Group C (bundled glass fiber post) with only 1 post adaptation failure [Table 1].
Numbers of failures: Group A > Group B > Group C.
| Discussion|| |
Endodontic treatment has progressed significantly over the decades, leading to greater knowledge, clinical success, and concomitant cost of endodontic treatment. It has been suggested that endodontically treated teeth are more brittle and may fracture more easily than vital teeth. The loss of tooth structure from caries or trauma also makes endodontically treated teeth more susceptible to fracture. To improve the fracture resistance of endodontically treated teeth, post and core techniques are clinically necessary to restore endodontically treated teeth. Failure in teeth that have been root canal treated is more likely to be the result of the failure of the restoration that has been placed, rather than the endodontic treatment itself.
Thus, the different materials used for post and core system in the study became the factors most crucially responsible for the variability in the clinical performance of the teeth over time. There is a lack of prospective studies on the clinical evaluation of post and core. Hence, this study was done to evaluate the treatment outcome of different post and core systems clinically and radiographically with 9-month follow-up.
The traditional custom-made cast post and cores provide a better geometric adaptation to canals with extremely tapered canals or those with a noncircular cross-section and/or irregular shape and roots with minimal remaining coronal tooth structure., However, there are some disadvantages associated with the conventional metal post and core systems as it is an alloy with a modulus of elasticity that can be as high as 10 times than natural dentin, this incompatibility can create stress concentrations and can transmit the occlusal forces in the less rigid area of the root and causing the greater incidence of root fracture, poor retention of the post, and risk of corrosion when different metals are used in the system. These failures are generally catastrophic and ultimately teeth require extraction. Fabrication of cast metal posts and cores can be time-consuming and involves additional laboratory procedures that may introduce errors within casting and thus increase the risk of failures. In this study, nickel-chromium alloy was used for the fabrication of cast metal posts (Group A).
Increase demand for esthetic dental restorations and advances in adhesive dentistry has led to the development of innovative post materials and techniques for the restoration of endodontically treated teeth. These newer systems, such as fiber-reinforced composite-resin posts (FRC posts), have become popular in the last few years. Fiber-reinforced composite resin posts have focused on physical properties, such as modulus of elasticity, that are closely matched to dentin to decrease stress concentration within the root canal and reduce the incidence of the root as well as post fracture. The modulus of elasticity of fiber-reinforced composite posts (16 GPa to 40 GPa) provides elevated shock resistance, shock absorption, weakening of vibration, and augmented fatigue resistance. Prefabricated fiber post mostly shows debonding as a mode of failure which is favorable and amenable to retreatment; the same was observed to one case in the present study. Most of the fiber posts can be removed from a root canal with ease and predictability when necessary, without compromising core retention in cases of endodontic retreatment. Glass fiber-reinforced resin post and core system used in this study, Rebilda Post (VOCO Gmbh, Cuxhaven, Germany) (Group B), has a modulus of elasticity of 24 GPa (90°), a transverse strength at 45° of 1904 MPa, and a transverse strength at 90° of 1240 MPa. It has a radiopacity of 350% Al, translucency of 27.2%, and a water absorption capacity of 10.6 μg/mm3.
The novel bundle glass fiber-reinforced resin post and core system, Rebilda Post GT (VOCO Gmbh, Germany) (Group C), contains approximately 70% glass fibers, approximately 10% fillers (> high radiopacity of 408% Al), and approximately 20% dimethyl acrylate matrix. Rebilda Post GT is characterized by high fracture resistance and flexural strength (1040 MPa), as well as high radiopacity (>408% Al), while its elasticity is similar to that of dentin (31.5 GPa). The diameter of a single fine post is 0.3 mm. Rebilda Post GT is indicated for all post/core buildups. Whether it is for treating a tooth with atypical anatomy or a mechanically prepared root canal, Rebilda Post GT is highly effective. Once initially seated, the sleeve is removed, the bundle is spread, and the fine individual posts are distributed in the entire root canal and can adapt to any root canal morphology without the requirement of specific drills. Hence, while using Rebilda Post GT minimal tooth substance needs to be sacrificed and there is no further weakening of the tooth structure. In contrast to conventional root posts, Rebilda Post GT provides homogeneous reinforcement to the entire core buildup by distributing the fine individual posts in the area of the core buildup. This increases the surface area and thus the adhesion and retention attained between the core build-up material and the Rebilda Post GT, resulting in a stronger buildup.
Hence, based on the results of previous studies, Group A was rehabilitated with a cast metal post, Group B was rehabilitated with a glass fiber post system (Rebilda Post), and Group C was rehabilitated with a bundle glass fiber post system (Rebilda Post GT).
Before post placement, the prepared space was rinsed with saline and dried with the help of a paper point. As per the manufacturer's instruction, silanization of glass fiber post (Rebilda Post, Group B) and bundle glass fiber post (Rebilda Post GT, Group C) was done with ceramic bond, which was allowed to act for 60 s and air-dried and then luted with dual-cure adhesive (e.g., Futurabond U). Then, the core build-up composite (Rebilda DC, VOCO Germany) was filled into the canal using an application tip, and the selected post was inserted. The custom-made cast metal post and core were cemented in the root canal using glass ionomer luting cement (GC).
The method of choice of the core buildup is a light-cured or dual-cure composite resin. Light-cured core build-up materials can be used in the form of increments. As light-cured core build-up materials are polymerized using light, the duration of the procedure can be adjusted according to clinical procedures, and the core structure can be given the desired form. Moreover, it ensures optimal color stabilization of the restoration. Dual-cure composite resins are often used both in post luting and building of the core structure under the final restoration to ensure a sufficient level of polymerization in areas where light cannot reach. In this study, dual-cure composite resin, Rebilda DC, was used in both Group B (glass fiber post) and Group C (bundle glass fiber post).
All teeth evaluated in this study received final lithium disilicate glass all-ceramic restorations, which showed high survival rates in a clinical review done by Fernandes et al. Similarly, in this study, no failure was found due to crown fracture. The use of the same final restoration for all teeth allowed us to assess the real effects of the posts on the survival of the tooth-restoration complex. The all-ceramic crowns for the anterior teeth were fabricated with the IPS e-max Ceram (Ivoclar Co, Lichtenstein) in a pressable ceramic processor using high opacity material for the ceramic framework, to avoid shimmering of the underlying metal post. Final cementation of all-ceramic crowns was carried out with self-adhesive resin cement (3M RelyX™ U200). Furthermore, the status of the antagonist's teeth and occlusion patterns of the crowns were evaluated because any problem related to these factors, such as incorrect occlusal contact, could generate a failure unrelated to the posts.
Maxillary anterior teeth were selected in this study because force directions differ in the anterior and posterior teeth, and the maxillary region is considered to be a high-risk area for technical failures because of greater horizontal forces. Thus, most failures in post-retained crowns occur in the maxillary anterior region. Moreover, the esthetic requirement is more in the maxillary anterior than any other region. Evidence-based studies have shown that traditionally cast metal post was used for rehabilitating maxillary anterior tooth, but with the advent of fiber posts, single-visit rehabilitation of fractured maxillary anterior teeth is possible. Hence, for rehabilitating maxillary anterior teeth, Group A (cast metal post, control), Group B (glass fiber post, test), and Group C (bundle glass fiber post, test) were selected.
The impact of the periodontal status on the survival of endodontically treated teeth was discussed by Naumann et al. Periodontal failures of endodontically treated teeth were the second most frequent cause of failure (32%) after crown fractures (60%). Increased reduction of bone support leads to a marked decrease in the load capability of a post retained post endodontic restoration. In the present study, the exclusion criteria have been very stringent where periodontal status as well as periapical status has been assessed preoperatively. Thus, cases with doubtful periodontal status, which might affect the prognosis, have not been included in the study. In this study, no cases with any deterioration in periodontal status were reported, which is similar to the results of the clinical study done by Sharma et al. and Preethi and Kala.
The results of this study are coinciding with the meta-analysis of literature done by Zhou and Wang, who demonstrated that teeth with cast posts had catastrophic failures, such as oblique or horizontal fractures in the middle third of the root or vertical fractures of the root. In this study, two root fractured cases were reported, both were of cast metal post group (Group A) and were nonpreservable and finally went for extraction. However, the failures that occurred with the fiber post systems were repairable in which one core fracture of fiber post group (Group B) occurred at the cervical third of roots and one failure of fiber post debonding occurred, both teeth were preserved after retreatment. One possible explanation is that fiber posts have a modulus of elasticity similar to that of dentin, which facilitates stress dissipation. For the fiber post groups, the space between the dentin canal walls and the post was wider and filled with resin cement in opposition to the cast posts that were molded to adjust the post shape to the canal walls. Thus, the thicker resin cement layer for fiber posts might have acted as stress absorption when the tooth was under occlusal force. Therefore, less force will be focused on the root. It also increases the ability of the force to spread, so the risk of root fracture will decrease.
In this study, 5 cases as post adaptation failure are considered in cast metal post system(Group A) in which more than 1 mm of space was present between the interface of cast metal post and obturating material. Failures could be induced at different stages of the procedure; it could be due to technical fault of the operator or errors during laboratory casting procedures. This adaptation failure can lead to further biological catastrophic failures in the treated tooth. Similarly, in this study, it was observed that out of 5 post adaptation failure cases in Group A (cast metal post) eventually led to 3 periapical pathologies and 1 with sinus tract formation during follow up radiographic evaluation.
The results of this clinical study follow the results of Uthappa R et al. where two failures of root fracture with cast metal group were observed during radiographic evaluation and no case of root fracture was reported in fiber post group.
This study showed no tooth mobility in any post type that is in contrast to the results of Uthappa R et al., where three patients of cast metal post group and one patient of fiber post group showed posttreatment tooth mobility.
In this study, both fiber post groups (Group B and Group C) showed a lesser failure rate than cast metal posts (Group A), which coincides with the results of a clinical study done by Sharma S. et al. The probability of survival of fiber post was more than that of cast metal post.
While comparing fiber post (Group B, Rebilda Post) with bundle glass fiber post (Group C, Rebilda Post GT), latter showed only one failure as post adaptation failure in which more than 1 mm of space was present in between the interface of Post and root dentin. Whereas, fiber post group (Group B, Rebilda Post) showed one debonding, one core fracture, and three cases with failure in proper post adaptation. For no debonding failure with bundle glass fiber post system (Group C, Rebilda Post GT), this study coincides with the finding of Mouafaq and Kadir and Bitter et al., where they stated that Rebilda GT post has a greater diameter than other single fiber posts and can be expanded, it may due to the design of Rebilda GT which have a bundle of posts and this gives more surface area for luting and better force distribution so the overall post diameter increase, the cement thickness decrease, so finally the mean bond strength increase. They also stated that the highest bond strength was for the Rebilda GT post, although it was not statistically significant. Since this study was a clinical study, bond strength was not evaluated.
In this study, bundled glass fiber post (Group C) has shown fewer voids (post adaptation failures) in radiographs when compared to fiber post (Group B), which is opposite to contrasting the results of the study done by Bitter et al., where more voids were seen in Bundled Rebilda Post GT.
Cast metal post as per the evidence-based study shows a metal sheen through the all-ceramic crown. It is recommended to use a porcelain fused metal crown in case of cast metal post. In this study, we have tried to circumvent the metal display by masking with the use of resin cement and using high opaque ceramic material. However, three esthetic failures were seen in Group A (cast metal post), which coincides with the study done by Michalakis et al., in which the author reported that poor esthetic resulted in a display of cast metal post because of the reflection, lack of light transmission, and shadow due to gingival discoloration.
Limitations of the study
- The limitation of the study was only 9 months of follow-up. For a comprehensive evaluation of treatment outcome, a longer follow-up is desirable
- Further, the mechanical behavior of each post type needs to be evaluated by stress analysis studies
- The mechanical behavior of each post type to different loading conditions such as mastication, trauma, and bruxism also needs to be evaluated
- Since this was a clinical study, the bond strength was not evaluated
- The above aspects can be an area of research in future studies.
| Conclusion and Recommendation|| |
Within the limitations of the study, it was observed in this study that grossly mutilated anterior teeth can be rehabilitated with different post and core systems such as cast metal post and core, glass fiber post and core system, and bundle glass fiber post and core system. Each post and core system has its inherent challenges and advantages and disadvantages.
The cast metal post successful outcome depends on the skill and dexterity of the operator and is also dictated by laboratory-induced errors. It was observed in this study that failures of cast metal post-retained crown restoration are biological catastrophic failures and failed teeth may require surgical intervention or extraction. Due to metal display which compromises esthetics, cast metal post retained all-ceramic crowns are not indicated for restoring maxillary anterior.
Whereas, fiber posts are the best alternative due to their various advantages such as modulus of elasticity similar to that of dentin, reduced treatment time, no laboratory-induced errors, and excellent clinical performance for restoring the maxillary anterior teeth.
The bundle glass fiber posts can be a reliable alternative due to various advantages as it can adapt any root canal morphology while preserving remaining root dentine thickness, provides homogenous reinforcement to the entire core buildup by distributing the fine individual posts in the area of core buildup, modulus of elasticity similar to that of dentin provides elevated shock resistance, shock absorption and prevents root fracture, and having excellent esthetic property.
If retreatment is indicated, drilling through the fiber post or bundle glass fiber post is easier. Tooth structure is preserved if retreatment is indicated.
In light of the limitations of this study design, both glass fiber post and core system and bundle glass fiber post and core system show promising results and appear to be a better alternative to the rigid cast metal post in clinical practice. However, bundle glass fiber post and core systems have shown a better treatment outcome than glass fiber post and core systems. Hence, it can serve as a viable postendodontic restorative option for rehabilitating mutilated maxillary anterior teeth in routine clinical practice, but long-term clinical trials are necessary to assess their mechanical properties and clinical performance.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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