Retentive strength of different intracanal posts in restorations of anterior primary teeth: an in vitro study

In Vitro Effect of Luting Cement on Fracture Resistance of Primary Maxillary Central Incisors with Fiber Posts

Objectives: The use of fiber posts in endodontically treated primary maxillary central incisors improves the retention of composite resin restorations. The purpose of this study was to evaluate the effect of 4 different luting cements on fracture resistance of primary maxillary central incisors with fiber posts. Materials and Methods: In this in vitro study, 40 primary maxillary central incisors were endodontically treated and obturated with Metapex. They were then randomly divided into four groups (n=10) for cementation of fiber posts with GC Fuji I glass ionomer luting cement, Panavia F2.0 dual-cure luting cement, Panavia SA Luting Plus cement (self-adhesive), and TotalCem self-adhesive cement. After 1000 thermal cycles, the fracture resistance was measured. Data were statistically analyzed using ANOVA (alpha=0.05). Results: The mean fracture resistance was 267.07±130.01N in TotalCem, 257.27±102.56N in Panavia F2.0 dual-cure cement, 227.82±110.40N in Panavia SA Luting Plus self-adhesive cement, and 220.89±59.96N in GC Fuji I glass ionomer group. There was no statistically significant difference in fracture resistance among the four groups (P=0.714). Conclusion: Type of luting cement had no significant effect on fracture resistance of primary maxillary central incisors with fiber posts. Nonetheless, TotalCem yielded the highest fracture resistance. Considering its self-adhesive property and easy workability, it can be a good option for cementation of fiber posts in endodontically treated primary central incisors.

Comparison of shear bond strength of different types of intracanal posts in restoring extensively damaged primary anterior teeth

Background

Severe caries in early childhood is a concern for both children receiving dental treatment and their parents. This dental disease progresses rapidly and quickly damages the coronal part of the tooth. When there is insufficient coronal structure to support a coronal restoration, using intracanal components following root canal treatment increases tooth resistance and helps provide retention for the coronal restoration. This study compared the shear bond strength of three types of intracanal posts (composite resin post, reverse metal post, and fiber post) in severely damaged primary anterior teeth.

Methods

This in vitro study was conducted on 30 extracted anterior primary teeth with at least two-thirds of healthy roots and no prior pulp treatment. The teeth were randomly divided into three groups of 10: group 1: composite resin post with 8th generation universal bonding, group 2: reverse metal post with GC restorative glass cement, and group 3: fiber post with GC restorative glass cement. After placing the post, the samples were restored with a height of 3 mm from cementoenamel junction (CEJ) using an Anterior GC Gradia Packable composite resin. All the samples underwent 500 cycles of thermocycling in a hot water bath at 55±2 °C and a cold water bath at 5±2 °C. The shear strength of the samples was then evaluated using an electromechanical universal testing machine at a rate of 1 mm/min and at a location 2 mm coronal to the CEJ in terms of megapascals.

Results

The average shear bond strength of composite resin posts with 8th generation bonding application was 8.02220 MPa, reverse metal posts with glass ionomer application was 13.8600 MPa, and fiber posts with glass ionomer application was 9.7400 MPa.

Conclusion

Based on these findings, it can be concluded that the highest shear bond strength in this study was related to the reverse metal post, and the lowest shear bond strength was related to the composite resin post. According to the results, reverse metal posts demonstrated better shear bond strength than composite resin posts and fiber posts (P<0.05).

Effects of glass fibers reinforced and non-reinforced composite resin on fracture behavior of severely destructed primary incisors and restored with post and core system

Objective

To evaluate fracture resistance and failure type of coronally rehabilitated primary incisors with EverX Flow or Grandio Core post and core with or without fiber post.

Materials and Methods

Forty-eight extracted maxillary primary incisors were root canal treated and obturated with Metapex. The coronal 4-mm of Metapex was removed to create 3-mm intracanal post space. Next, coronal enamel and radicular dentin surfaces were acid-etched, and a bonding agent was applied and light-cured. Based on intracanal post and 2-mm height core buildup materials, specimens were divided equally (n = 12) into 4 groups as follow; Group I (EverX Flow), Group II (Grandio Core), Group III (Fiber post, and EverX Flow), and Group IV(Fiber post and Grandio Core). The coronal restorations were finalized to 4-mm height using G-aenial Anterior composite and specimens were tested for fracture resistance. Force required to induce fracture was recorded and failure type was examined.

Results

Fracture resistance of Fiber post and EverX Flow group was statistically significant high than other tested groups. However, fracture resistance of EverX Flow group showed non-statistically significant difference from that of Fiber post and Grandio Core group. Regarding failure type, no specimen presented root fracture, and all failures were favorable and repairable.

Conclusion

EverX flow post and core with or without fiber post enhanced fracture resistance of restored primary incisors compared to Grandio Core alone.

Clinical relevance

EverX flow post and core system with or without fiber post could be a promising restorative option for severely destructed primary incisors.

Evaluation of the Effects of Different Types of Resin Cement Systems on the Push-Out Bond Strength of the Fiber Post to Intracanal Dentin in Anterior Primary Teeth

Background

This study aimed to evaluate the effects of using three different resin cements on push-out bond strength (PBS) of fiber posts to root canal dentin of primary teeth.

Methods

Fifty primary canines were randomly divided into five experimental groups according to the type of the luting agent used for fiber post cementation after endodontic treatment and post space preparation as the following: Group 1: glass ionomer cement (GIC), Group 2: flowable resin composite, Group 3: etch and rinse (E&R) resin cement, Group 4: self-etch (SE) resin cement, Group 5: self-adhesive (SA) resin cement. The PBS values of the cemented fiber posts to root canals were measured. The data were statistically analyzed using a one-way analysis of variance, followed by Tukey's post hoc test.

Results

The highest mean PBS value was observed in Group 4 (SE resin cement), followed by Group 3 (E&R resin cement), and the lowest PBS value belonged to Group 1 (GIC), followed by Group 5 (p-values < 0.05). The mean PBS of Group 3 (E&R resin cement) was significantly higher than those of Groups 1 (GIC), 2 (flowable resin composite), and 5 (SA resin cement) (p-values < 0.05). However, no significant difference was found between the mean PBS of GIC and SA resin cement (p-value >0/05).

Conclusion

Using SE resin cement for fiber post cementation in primary anterior teeth showed the best results, followed by E&R resin cement. The lowest PBS was observed for GIC, followed by SA resin cement.

Mechanical Properties and Clinical Success of Intracanal Posts in Primary Maxillary Anterior Teeth: A Systematic Review and Meta-analysis

Background

Intracanal posts are commonly used to restore lost permanent/primary tooth structure and the smile of the patient.

Aim

This systematic review aims to evaluate the clinical success of intracanal posts used in primary maxillary anterior teeth and compare their mechanical properties.

Methods

An extensive literature search was performed using Medline via PubMed, Embase via embase.com, LILACS, CINAHL via EBSCO, Cochrane Oral Health Group Specialized Register, Scopus, and Web of Science until December 2021 and was updated till December 2022. In vivo and in vitro studies in the English language that assessed clinical success and mechanical properties were included. Distiller SR software was used for everything from title screening to data extraction.

Results

A total of 30 studies were analyzed, including 11 in vivo and 19 in vitro studies. Four studies were included in a meta-analysis, and all 30 studies qualified for qualitative analysis. The meta-analysis showed that fiber posts are clinically superior to composite resin posts (CRPs) (p = 0.02). No significant difference was observed between the fracture resistance of CRPs and no posts (p = 0.73). Most of the included studies showed a high risk of bias.

Conclusion

Conclusive evidence about the effectiveness of various intracanal posts cannot be established. This is due to the limited number of clinical trials and included studies of low to moderate quality with a high risk of bias. To validate the use of posts in primary maxillary anterior teeth, further research, including randomized controlled trials (RCTs) of higher quality, is required.

Clinical significance

The use of intracanal posts in primary teeth is a commonly used treatment modality among pediatric dentists. However, the quality of the evidence to support its use is low. This systematic review provides a comprehensive summary of the current literature and highlights the need for further research. Results were interpreted with caution, as the evidence supporting the use of intracanal posts in primary teeth is limited.

How to cite this article

Shanmugam Y, Raghu A, Muthu MS, et al. Mechanical Properties and Clinical Success of Intracanal Posts in Primary Maxillary Anterior Teeth: A Systematic Review and Meta-analysis. Int J Clin Pediatr Dent 2023;16(S-3):S293-S305.

Comparison of the Pull-Out Resistance of Grossly Decayed Primary Anterior Teeth Restored With Two Different Intracanal Posts: An In Vitro Study

Background Severely damaged primary anterior teeth that require pulp therapy present a high risk of failure due to the loss of tooth substance, resulting from pre-existing decay and endodontic therapy. The ideal post material should have physical and mechanical properties similar to those of dentin. Another concern in restoring endodontically treated primary teeth is the need to find a material that can resorb similar to the natural tooth structure as a part of the exfoliation process, allowing normal eruption of permanent successors. Accordingly, there is no such material other than dentin itself. The introduction of biological dentin posts offers an excellent alternative for restoring such teeth. This study aimed to assess the effect of using dentin posts on the pull-out resistance of endodontically treated primary anterior teeth in comparison to glass fiber posts. Methodology A sample of 30 primary anterior teeth was collected from the outpatient clinic of the Pediatric Dentistry Department, Faculty of Dentistry, Damascus University. A total of 15 freshly extracted permanent teeth with single roots were also collected from the outpatient clinic of the Maxillofacial Surgery Department, Faculty of Dentistry, Damascus University. The roots of the permanent teeth were used to prepare 30 dentin posts using a CAD-CAM machine. After receiving proper endodontic treatment, the primary teeth were divided into two groups (15 teeth in each group). The first group was restored with dentin posts, and the second was restored with glass fiber posts, with the posts measuring 3 mm in length for both groups. Pull-out resistance testing was performed using a Testometric machine. Results The arithmetic mean of the forces applied in the glass fiber posts group was 153.2 ± 39.12 N, while the arithmetic mean of the forces applied in the dentin posts group was 156.7 ± 39.78 N. The data were analyzed at a 95% confidence interval using the independent Student's t-test. There were no statistically significant differences in pull-out resistance between the two groups. Conclusions Dentin posts showed a little increase in pull-out resistance than glass fiber posts. Therefore, the use of dentin posts as intracanal retention in primary anterior teeth is a successful alternative for composite posts.

Comparison of fracture resistance of primary incisor teeth restored with glass fiber post and reversed-oriented metal post - An in vitro study

Background

This in vitro study aimed to compare the fracture resistance of fiber post and reversed-oriented metal post in the restoration of severely decayed primary incisors.

Materials and Methods

In this in vitro study, forty extracted human primary incisors were sectioned horizontally 1 mm above the CEJ and randomly divided into four groups - Group 1: Central incisors restored with reverse-oriented metal post, Group 2: Lateral incisors restored with reverse-oriented metal post, Group 3: Central incisors restored with fiber post, and Group 4: Lateral incisors restored with fiber post. The coronary portion of the teeth was then restored with nanohybrid universal composite. The fracture resistance was measured using universal testing machine. The type of fracture was determined by employing a stereomicroscope. Data were analyzed using two-way ANOVA test. The level of significance was considered at P < 0.05.

Results

The mean fracture resistance of glass fiber posts (208.00 ± 73.19) was higher than the reverse-oriented metal posts (190.37 ± 56.36); however, there was no significant difference between any of the groups (P = 0.353).

Conclusion

Within the limitations of this study, it can be concluded that both types of posts studied in the present research can be successfully used in the restoration of severely damaged primary incisors.

Clinical and radiographic comparative study to evaluate the efficacy of restoring destroyed primary incisors using two different techniques-A pilot study

Objective: The restoration of destroyed maxillary primary incisors is difficult because of the insufficient amount of coronal structure. This pilot study aimed to compare the efficacy of composite posts technique and glass fiber posts technique in restoring destroyed primary incisors.

Materials and Methods: Thirty‐six destroyed maxillary primary incisors in 11 children with early childhood caries were randomly assigned after endodontic treatment into two groups: glass fiber posts (n = 18) and composite resin posts (n = 18). Blinded clinical evaluation was made at 3, 6, 9, and 12 months and Blinded radiographic evaluation was made at 6 and 12 months. The evaluation was according to the FDI criteria. Data were analyzed with Fisher's exact test (α = .05).

Result: After 12 months post‐treatment, the success rates were 88.2% in glass fiber posts group and 70.6% in composite resin posts group. There was no statistically significant difference between the two groups according to the evaluation criteria (p‐value >.05).

Conclusion: Glass fiber posts technique and Composite posts technique may be used in the restoration of destroyed primary incisors.

Fracture Resistance of a Bulk-Fill and a Conventional Composite and the Combination of Both for Coronal Restoration of Severely Damaged Primary Anterior Teeth

Objectives:

This study aimed to compare the fracture resistance of a bulk-fill and a conventional composite and a combination of both for coronal restoration of severely damaged primary anterior teeth.

Materials and Methods:

In this in vitro experimental study, 45 primary anterior teeth were randomly divided into three groups. After root canal preparation, the canals were filled with Metapex paste such that after the application of 1 mm of light-cure liner, 3 mm of the coronal third of the canal remained empty for composite post fabrication. Filtek Z250 conventional composite was used in group 1, Sonic-Fill bulk-fill composite was used in group 2 and Sonic-Fill with one layer of Filtek Z250 as the veneering were used in group 3. Adper Single Bond 2 was used in all groups. The teeth were thermocycled, and fracture resistance was measured by a universal testing machine. The mode of fracture was categorized as repairable or irreparable. Data were analyzed using one-way ANOVA.

Results:

The mean fracture resistance was 307.00±74.72, 323.31±84.28 and 333.30±63.96 N in groups 1 to 3, respectively (P=0.55). The mean fracture strength was 14.53±2.98, 15.08±2.82 and 15.26±3.02 MPa in groups 1 to 3, respectively (P=0.77). The frequency of repairable mode of failure was 80% for the conventional, 73.6% for the bulk-fill and 80% for the bulk-fill plus conventional group, with no significant difference (P>0.05).

Conclusion:

Bulk-fill composites can be used for coronal reconstruction of severely damaged primary anterior teeth similar to conventional composites to decrease the treatment time in pediatric patients.

Effect of Layering Technique on Push-Out Bond Strength of Composite Resin to Intracanal Dentin of Primary Anterior Teeth

OBJECTIVES

This in-vitro study aimed to compare the push-out bond strength of composite resin posts packed into the root canal of primary anterior teeth using two different layering techniques.

MATERIALS AND METHODS

Thirty-two primary anterior teeth were randomly divided into two groups. In group 1, after the preparation of post spaces, a posterior composite resin (Filtek P60) was packed in three horizontal layers by a composite condenser instrument with a cylindrical tip using the horizontal layering technique (HLT). In group 2, this was done using a condenser with a conical tip in three funnel-shaped layers according to the funnel-shaped layering technique (FSLT). Next, the specimens were subjected to push-out bond strength testing. Data were analyzed using t-test and the Kaplan-Meier curves.

RESULTS

The mean±standard deviation (SD) bond strengths of composite resin posts were 8.46±3.45 MPa and 7.7±2.24 MPa for the HLT and FSLT, respectively; the difference was not statistically significant (P=0.46).

CONCLUSIONS

The layering technique by which composite resin was packed into the root canal of primary anterior teeth (HLT versus FSLT) had no significant effect on the push-out bond strength of composite resin posts.

Coronal Microleakage of Teeth Restored with Cast Posts and Cores Cemented with Four Different Luting Agents after Thermocycling

PURPOSE

The apical seal provided by a root canal filling may be breached via coronal leakage. This study aimed to compare the teeth restored with custom-made cast metal posts and cores cemented with different luting agents in terms of coronal microleakage after thermocycling.

MATERIALS AND METHODS

This in vitro study was conducted on 32 extracted single-canal teeth. Root canals were prepared by step-back technique and filled with gutta percha and sealer. The coronal 7 mm of gutta percha was removed, and post space was prepared using peeso reamers #2 and #3 consecutively. After fabricating the acrylic resin patterns of the posts and cores, they were cast using Ni-Cr metal alloy. The specimens were divided into 4 groups in which the castings were cemented using one of the following luting agents: zinc phosphate (ZP), glass ionomer (GI), Panavia F 2.0, and Speed CEM. After cementation, the teeth were immersed in distilled water and incubated for 7 days. Then, the teeth were subjected to thermocycling, immersed in silver nitrate for 6 hours, and finally sectioned. The degree of dye penetration into the coronal part of the specimens was measured using a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitey U tests with significance level of 0.05.

RESULTS

The median microleakage in ZP, Speed CEM, GI, and Panavia were 171.89, 114.76, 26.51, and 20.02 μm, respectively. Pairwise comparisons among GI and ZP, GI, and Speed CEM, ZP and Panavia, ZP and Speed CEM, and Panavia and Speed CEM groups yielded significant differences (p < 0.05).

CONCLUSION

Complete coronal seal was not achieved with any of the luting agents. The highest and the lowest degree of microleakage was yielded by ZP and Panavia luting agents, respectively.

Evaluation of the effect of different post materials and adhesive systems on the bonding strength of short-post technique for primary teeth

BACKGROUND

The most important process in treating grossly decayed teeth, including decay in the pulp, is the ability to hold a retainer in for a short time.

AIM

The aim of this study was to investigate the bond strengths of different adhesive systems and post materials on primary teeth.

DESIGN

One hundred and twenty extracted maxillar primary central incisor teeth were randomly divided into two main groups (total-etch and self-etch adhesive systems) and five subgroups (1: control-nanohybrid composite resin, 2: pre-impregnated glass fiber, 3: unsaturated glass fiber, 4: polyethylene fiber, 5: short-fiber reinforced composite resin). The push-out test was performed using a universal testing machine with a crosshead speed of 0.5 mm/min.

RESULTS

No statistically significant difference was detected between the two different adhesive systems and five different materials in terms of the maximum values measured for fractures in the specimens when both the adhesive materials and the short-post materials were evaluated separately (P > 0.05). However, as a result of multiple comparisons made, it was found that statistical differences between the groups applying the total-etch adhesive system occurred in Groups 3 and 5. The highest push-out test values were measured in Group 5 and Group 1, and the lowest value in Group 3. Although the fracture type distribution in the total-etch adhesive system groups was not statistically different based on the material used (χ²  = 11,865; P = 0.309), the self-etch adhesive systems did show differences (χ²  = 28,463; P < 0.001). Both the total-etch and the self-etch adhesive system groups showed mostly adhesive failures.

CONCLUSION

The fiber-reinforced and nanohybrid composite resin had higher values in the short-post technique, and there was no significant difference between the different fiber posts.

Effect of Mechanical and Chemical Root Surface Treatment on the Shear Bond Strength of Intracanal Post in Primary Anterior Teeth: An In vitro Study

INTRODUCTION

Aesthetic restoration of severely mutilated primary anterior teeth still remains as a special challenge to paediatric dentist. Due to increased parent's concern for aesthetic rehabilitation for their children, paediatric dentist are in a state to improve technique sensitive restorative procedure to improve aesthetic rehabilitation in children.

AIM

The purpose of the study was to evaluate the effect of different root surface treatment on the shear bond strength of glass fibre reinforced post in primary anterior teeth using Universal Testing Machine (UTM).

MATERIALS AND METHODS

Twenty single rooted primary anterior teeth were selected. Coronal portions of the teeth were sectioned transversally 2 mm above the Cemento-Enamel Junction (CEJ) and specimens were treated endodontically and obturated using metapex. Then the specimens were randomly divided into four groups. Group 1: Control group; Group 2: Chemical surface treatment of the root with 2% chlorhexidine; Group 3: Mechanical surface treatment with mushroom-shaped undercut; Group 4: Combination of mechanical and chemical surface treatments. Samples were tested for shear bond strength. ANOVA and Post-hoc Tukey test were used for statistical analysis using SPSS version 20.0.

RESULTS

Combination of mechanical and chemical surface treatments exhibited higher mean shear bond strength (8.41 MPa), followed by mechanical surface treatment (4.68 MPa), chemical surface treatment (3.92 MPa) and control group (2.76 MPa).

CONCLUSION

Mechanical and chemical surface treatments together led to a improved shear bond strength and increased the retention of the post to the root surface.

Push-out bond strength of different intracanal posts in the anterior primary teeth according to root canal filling materials

Background:

This study was carried out to evaluate the effect of root canal filling on the bond strength of three intracanal posts in the primary incisors.

Materials and Methods:

Sixty primary incisors were prepared and then divided into two groups (n = 30). The first group canals obturated with zinc oxide eugenol (ZOE) and Group 2 canals obturated with Metapex. Further, the two group categories were divided into three subgroups (n = 10): (1) short composite post (SCP), (2) glass fiber posts (GFPs) cemented with flowable composite, and (3) GFP with glass ionomer cement (GFP + GIC). The push-out test was performed with a universal testing machine. The results were statistically analyzed with two-way analysis of variance.(α = 0.05).

Results:

The mean bond strength of the first group obturated with ZOE was lower than that of the second group obturated with Metapex (P = 0.046). Moreover, from a statistical point of view, in all three subgroups, the correlation of mean push-out bond strength between SCP and GFP coated with flowable composite was not substantial at P = 0.97. However, the mean bond strength of SCP was in fact significantly greater than that of the GFP coated with GIC since P = 0.034.

Conclusion:

Using ZOE resulted in the significant reduction of the mean bond strength of the intracanal posts when utilized in the primary anterior teeth. Likewise, SCP and GFP coated with flowable composite showed higher push-out bond strengths for restoring primary anterior teeth.

Comparison of Push-Out Bond Strength of Two Bulk-Fill and One Conventional Composite to Intracanal Dentin in Severely Damaged Primary Anterior Teeth

OBJECTIVES

This study sought to compare the push-out bond strength of two bulk-fill and one conventional composite to intracanal dentin in primary anterior teeth.

MATERIALS AND METHODS

This in vitro, experimental study was conducted on 39 primary anterior teeth, which were randomly divided into three groups. After cleaning and shaping, the root canals were filled with Metapex in such a way that after the application of 1mm light-cure liner on top of it, the coronal 3mm of the canal remained empty for composite post space. Z250 conventional composite was used in group 1 and SonicFill and Filtek bulk-fill composites along with Single Bond 2 were used in groups 2 and 3, respectively. The samples were subjected to thermocycling. One-millimeter thick sections were made of the mid-root and subjected to push-out bond strength test. Mode of failure was determined under a stereomicroscope at ×25 magnification. The data were analyzed using one-way ANOVA.

RESULTS

The mean (±standard deviation) push-out bond strength was 11.40±4.23MPa, 10.94±6.69MPa and 8.79±4.12MPa in the conventional, SonicFill and Filtek groups, respectively. The difference in this regard among the three groups was not statistically significant (P=0.397).

CONCLUSIONS

Based on the results, bulk-fill composites, similar to conventional types, can be successfully used for the fabrication of composite intracanal posts in primary teeth to decrease the treatment time in children.

Effect of ultrasonic tip designs on intraradicular post removal

Objectives

To evaluate the effect of different ultrasonic tip designs on intraradicular post removal.

Materials and Methods

The crowns of forty human canine teeth were removed, and after biomechanical preparation and filling, the roots were embedded in acrylic resin blocks. The post spaces were made, and root canal molding was performed with self-cured acrylic resin. After casting (Cu-Al), the posts were cemented with zinc phosphate cement. The specimens were randomly separated into 4 groups (n = 10), as follows: G1 - no ultrasonic vibration (control); G2 - ultrasonic vibration using an elongated cylindrical-shaped and active rounded tip; G3 - ultrasonic vibration with a flattened convex and linear active tip; G4 - ultrasonic vibration with active semicircular tapered tip. Ultrasonic vibration was applied for 15 seconds on each post surface and tensile test was performed in a Universal Testing Machine (Instron 4444 - 1 mm/min).

Results

G4 presented the highest mean values, however, with no statistically significant difference in comparison to G3 (P > 0.05). G2 presented the lowest mean values with statistically significant difference to G3 and G4 (P < 0.05).

Conclusions

Ultrasonic vibration with elongated cylindrical-shaped and active rounded tip was most effective in reducing force required for intraradicular post removal.