Comparative evaluation of mineral trioxide aggregate and biodentine apical plug thickness on fracture resistance of immature teeth: An In vitro study
Pramod Mohite1, Ankita Dadarao Ramteke2, Ruchika Gupta3, Suvarna Patil1, Divya Gupta3
1 Department of Conservative Dentistry and Endodontics, Vasantdada Patil Dental College and Hospital, Sangli, Maharashtra, India
2 Department of Conservative Dentistry and Endodontics, VSPM Dental College and Research Centre, Nagpur, Maharashtra, India
3 Department of Conservative Dentistry and Endodontics, D Y Patil Dental School, Lohegaon, Pune, Maharashtra, India
Correspondence Address:
Ruchika Gupta
C/O Pradeep Patil, Flat Number 505, Anand Tarang Society Near Hotel Rasrang, Alandi Road, Charholi, Pune, Maharashtra
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/aam.aam_97_20
Aim: This study aims to compare the fracture resistance of simulated immature teeth after using different thicknesses of Mineral Trioxide Aggregate (MTA) and Biodentine apical plug. Materials and Methods: Forty human maxillary anterior teeth were selected. Teeth were randomly divided into eight groups of five teeth in each group. Positive control group = 5 teeth; prepared without access cavity preparation. Access cavities of the remaining 35 teeth were prepared, and instrumented with Peeso reamers. Negative control = 5 teeth; filled with calcium hydroxide. Thirty teeth divided into Groups 1 and 2 of MTA (MTA-Angelus, Londrina, Brazil) and Biodentine (Septodant, Saint Maur des Fosses, France) and each group divided into three subgroups: subgroup A - 3 mm apical plug; subgroup B - 6 mm apical plug; and subgroup C: full canal length. The rest of the canals in subgroups A and B were filled with gutta-percha and AH Plus sealer. After the required storage period, all the samples were subjected to fracture testing under universal testing machine and fracture strength was recorded. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons. Results: The negative control group showed the lowest fracture resistance compared with the other groups (P < 0.0001). The 6-mm apical plug subgroup of biodentine showed the highest fracture resistance. Conclusion: Within the limitations of this study, MTA and Biodentine can be used as an apical plug instead of root canal filling material to increase the fracture resistance of immature teeth.
Résumé
Objectif: Cette étude vise à comparer la résistance à la fracture de dents immatures simulées après utilisation de différentes épaisseurs de trioxyde minéral Agrégat (MTA) et bouchon apical Biodentine. Matériel et Méthodes: Quarante dents antérieures maxillaires humaines ont été sélectionnées. Les dents étaient divisé au hasard en huit groupes de cinq dents dans chaque groupe. Groupe témoin positif = 5 dents; préparé sans préparation de la cavité d'accès. Les cavités d'accès des 35 dents restantes ont été préparées et instrumentées avec des alésoirs Peeso. Contrôle négatif = 5 dents; rempli de calcium hydroxyde. Trente dents réparties en groupes 1 et 2 de MTA (MTA-Angelus, Londrina, Brésil) et Biodentine (Septodant, Saint Maur des Fosses, France) et chaque groupe divisé en trois sous-groupes: sous-groupe A - bouchon apical de 3 mm; sous-groupe B - bouchon apical de 6 mm; et sous-groupe C: longueur totale du canal. Les autres canaux des sous-groupes A et B étaient remplis de gutta-percha et de scellant AH Plus. Après le stockage requis période, tous les échantillons ont été soumis à des essais de fracture sous une machine d'essai universelle et la résistance à la rupture a été enregistrée. Les données étaient analysé à l'aide d'une analyse de variance unidirectionnelle avec le test post hoc de Tukey pour des comparaisons multiples. Résultats: le groupe témoin négatif a montré la résistance à la fracture la plus faible par rapport aux autres groupes (p <0,0001). Le sous-groupe du bouchon apical de 6 mm de la biodentine a montré le plus résistance à la fracture. Conclusion: Dans les limites de cette étude, le MTA et la Biodentine peuvent être utilisés comme bouchon apical au lieu de canal radiculaire matériau de remplissage pour augmenter la résistance à la fracture des dents immatures.
Mots-clés: bouchon apical, biodentine, résistance à la fracture, agrégat de trioxyde minéral
Keywords: Apical plug, biodentine, fracture resistance, mineral trioxide aggregate
Dental impact injuries most often occur in children between the ages of 8 and 12 years.[1] The most common site of dental injuries in developing dentition in the maxillary anterior teeth mostly maxillary central incisor (36%). Such injuries often lead to pulpal necrosis which could cause the cessation of root formation in developing teeth.[1] It has been stated that the endodontically treated immature teeth have a relatively high incidence (>60%) of cervical root fracture, either spontaneously or due to minor impacts.[2]
Dentinal thickness is one of the most important factors for determining the resistance of the root fracture.[3] The open apex and dentinal wall thickness of immature teeth create a problem for endodontic and restorative treatment.[1]
Root canal instrumentation and the adequate apical stop achievement are challenges during root canal treatment of immature teeth.[4] The apexification is the procedure that is carried to provide an apical seal for the condensation of filling material by an artificial apical barrier. Apexification is defined as “a method to induce a calcified barrier in a root with an open apex or the continued apical development of an incomplete root in teeth with necrotic pulp.[5]”
Calcium hydroxide (Ca[OH] 2) apexification is the conventional treatment to promote the formation of an apical barrier with success rates ranging from 79% to 96%.[1] It has shown adequate apical healing by means of the induction of an apical barrier and the antibacterial capability due to its high pH.[6],[7],[8] However, it has disadvantages such as requiring multiple visits micro leakage between visits making it prone for reinfection and the patient's adaptation.[5],[6],[8] Andreasen et al.[6] suggested that long term use of Ca (OH) 2 increases the risk of root fracture. Furthermore, these teeth showed a 50% reduction in strength against controls over 1 year[6] and were compromised by cervical root fractures[2],[9] because changes in organic matrix of dentin. Such drawbacks were addressed by the single visit apexification treatment.
Single visit apexification is defined as nonsurgical condensation of biocompatible material into the apical end of root canal.[10] Single visit apexification treatment using (mineral trioxide aggregate [MTA]),[4] Biodentine may be used to replace the Ca(OH) 2 because of its good physical, chemical, and biological properties.[11]
MTA, which has a good root sealing ability and a high degree of biocompatibility, has been demonstrated to have good potential as an aid in the formation of apical hard tissue.[12] This material consists of tricalcium oxide and other mineral oxides and shows an alkaline reaction in aqueous slurries (pH >11).[13] It has been highly recommended for the apical retrograde root filling, apexification, and pulp capping.[14],[15],[16] Although MTA is a suitable material for clinical use, it has certain disadvantages such as a prolonged time for setting, difficulty in handling, and the probability of discoloration.[17]
Recently, biodentine - a calcium silicate based material have been introduced to overcome the drawbacks associated with MTA. It is used for retrograde root filling, perforation repair, vital pulp therapy, and induction of apical closure in incompletely developed teeth.[15] These materials trigger the release of Ca(OH) 2 in a solution that on contact with the tissue fluids forms hydroxyapatite.[18]
Of all the materials available, MTA and biodentine has been widely used for single visit apexification because of its superior sealing ability, biocompatibility, regenerative capability, and antibacterial property; it also enhances the fracture resistance of immature teeth. Recent studies evaluated the success of MTA and biodentine in the treatment of immature teeth. However, the optimal thickness of an MTA and biodentine apical plug is controversial.
Therefore, the aim of study is to compare the fracture resistance of simulated immature teeth after using different thicknesses of an MTA and biodentine apical plug.
Materials and MethodsTooth selection
Forty extracted human maxillary anterior teeth with a single root and canal were selected. Periapical radiographs were taken to verify the absence of calcification, internal resorption, or an additional root canal. Teeth with carious lesions, calcified canal, root resorptions, and root fractures were discarded. Teeth with a length of 20 ± 0.51 mm were selected for standardization. The apical 5 mm of each tooth was removed using a low-speed diamond saw.
Procedures
Five teeth served as the first control which is prepared without any access cavity preparation, from the apical to the coronal direction of the canal using Peeso reamers with size 1 up to size 5 to simulate immature teeth.
Thirty-five teeth were prepared using a high-speed handpiece (NSK, Japan) with a size 4 round bur. The canals were instrumented with Peeso reamers (Mani) until a size 5 Peeso such that it can easily pass 1 mm beyond apex to simulate the immature teeth. The canals were irrigated with 2.5% sodium hypochlorite during instrumentation. A size 6 Peeso reamer was used to extend the preparation of the canal 3 mm below the cementoenamel junction to simulate the Cvek's stage 3 of root development, i.e., development was provided for this model because the root-to-canal ratio in a mesiodistal dimension at the cementoenamel junction is approximately 1:1 at this stage.[2],[3],[4]After the instrumentation, each canal was irrigated with 3 mL 3% sodium hypochlorite (Prime Dental) and then irrigated with 3 mL saline (Abaris Healthcare Pvt. Ltd.).
Five teeth served as the second control, and the canals were filled with Ca(OH) 2 (Prime Dental). The access cavity was sealed with a temporary filling material (Cavit; ESPE, Seefeld, Germany) and the specimens were stored at 37°C and 100% humidity for 4 weeks to simulate the oral environment.
Teeth were randomly divided into 2 experimental groups (n = 15). Group 1 and Group 2 are further divided into three subgroups in following manner according to material of choice:
Group 1: MTA (MTA –Angelus, Londrina, Brazil).
Subgroup A: MTA was placed in immature teeth and condensed with hand plugger to obtain 3 mm apical plug thicknessSubgroup B: MTA was placed in immature teeth and condensed with hand plugger to obtain 6 mm apical plug thicknessSubgroup C: MTA was placed in immature teeth and condensed with hand plugger to obtain a completely obturated root canal with a material.Group 2: BIODENTINE (Septodant, Saint Maur des Fosses, France).
Subgroup A: Biodentine was placed in immature teeth and condensed with hand plugger to obtain 3 mm apical plug thicknessSubgroup B: Biodentine was placed in immature teeth and condensed with hand plugger to obtain 6 mm apical plug thicknessSubgroup C: Biodentine was placed in immature teeth and condensed with hand plugger to obtain a completely obturated root canal with a material.All specimens were stored at 37°C and 100% humidity for 4 h to simulate oral environment. In subgroups 1 and 2, remaining parts of the canals, i.e., coronal to apical plug were filled with thermoplasticized gutta-percha (Sure endo-sure dent corporation, Korea) after application of AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). The quality of the obturation was confirmed with periapical radiographs [Figure 1]. The access cavities were sealed with resin composite restoration. The samples were stored at 37°C and 100% humidity for 4 weeks.
Figure 1: (a) Positive control group. (b) Negative control group. (c) Mineral trioxide aggregate GROUP: a-full canal subgroup; b-6mm subgroup; c-3mm subgroup. (d) Biodentine Group: (a) full canal subgroup; (b) 6 mm subgroup; (c) 3 mm subgroupFracture testing
The root surfaces were covered with a polyether impression material to mimic the periodontal membrane. The roots were embedded in self-curing resin blocks until there was a 2-mm gap between the cementoenamel junction and the top of the resin (DPI-RR). Each specimen was mounted in a universal testing machine (INSTRON) [Figure 2]. The samples were loaded at a crosshead speed of 1 mm/min until the fracture occurred.
The spade, which was used to apply the force to the specimen, was placed on the facial surface at a point 3 mm above the cementoenamel junction at 135° to the long axis of the tooth in a buccal/lingual direction to stimulate a traumatic blow on the middle third of the crowns [Figure 3].[19] The samples were loaded at a crosshead speed of 1 mm/min. The teeth were fractured horizontally or obliquely through the cervical area of the root. The peak load to fracture was recorded in Newtons.
Statistical analysis
After completing the fracture test, the data were subjected to statistical analysis using 1-way analysis of variance with the Tukey post hoc test for multiple comparisons and intergroup comparisons. Statistical Product and Service Solutions version 21 for Windows (Armonk, NY, USA: IBM Corp) software was used to analyze the data. The testing was performed at the 95% level of confidence (P < 0.5).
ResultsThe second control group showed the lowest fracture resistance compared with the other groups (P < 0.0001). The 6-mm apical plug group of biodentine showed the highest fracture resistance as explained in [Table 1].
Table 1: The mean peak load (newtons) and standard deviation of the groupsNo significant differences were found among MTA and Biodentine groups (P = 0.423) between 3-mm apical group MTA (695.6 N) BIODENTINE (717.1 N), (P = 0.449) 6-mm apical group MTA (706.2 N) BIODENTINE (741.6 N). However, full canal groups showed significant difference (P = 0.003) [Table 2] and [Figure 4].
Table 2: Comparison of fracture resistance of mineral trioxide aggregate and biodentine at 3 mm plug, 6 mm plug and full length fillFigure 4: Fracture resistance showing intergroup comparison between mineral trioxide aggregate and biodentine DiscussionAs immature teeth are more fragile due to thin dentinal walls, they are more prone to fracture mostly in cervical area. The frequency of cervical root fracture in immature teeth has been stated to range from 2% in a 11-year-old to 77% in a 6 years old.[2]
The present study revealed that complete obturation with MTA decreased the fracture resistance of the roots compared with intact immature teeth [Figure 5]. However, the fracture resistance of the roots that were completely filled with MTA and BIODENTINE was significantly higher compared with the Ca (OH) 2 treatment group [Table 1]. It has been reported that root canal fillings with Ca (OH) 2 will lead to the weakening of endodontically treated teeth, and this finding can contribute to the change in the organic matrix of dentin.[6],[20]
Figure 5: Intragroup comparison between fracture resistances of mineral trioxide aggregate subgroupsAndreasen et al.[6] stated that the Ca (OH) 2 placed in the root canal had significantly negative effect on the strength of the root. The mechanism by which dentin was weakened may be related to a change in the organic matrix. A dissolving effect by Ca(OH) 2 on pulp tissue in just 1 week has been reported. This action is supposed to take place by denaturation and hydrolysis. If the phenomenon is related to the pH-changes in dentin observed after Ca(OH) 2 treatment an extensive alteration of dentin by Ca(OH) 2 could be expected. This would leave the dentin structure with reduced organic support, which may influence the mechanical properties of dentin.
Recent literature indicated that there is no research on the effect of MTA and Biodentin apical plug thickness on the fracture resistance of immature teeth.
However, there were controversial results regarding the strengthening ability of MTA. White et al.[21] reported that MTA and sodium hypochlorite reduce the fracture susceptibility of bovine dentin by 33% and 59%, respectively compared to the control group. They also showed a weakening of the dentinal structure in the short-term and attributed this effect to the structural alteration of proteins caused by the alkalinity of MTA.
Andreasen et al.[22] reported that MTA strengthens the cervical fracture resistance of immature sheep incisors more effectively than Ca(OH) 2. Milani et al.[23] conclude that MTA and calcium enriched mixture cement exhibited a distinct reinforcing effect on immature teeth after 6 months.
Biodentine represents a great improvement compared to the other calcium silicate dental materials. In contrast with MTA, the mechanical properties of Biodentine are similar to those of natural dentin. The material is stable, less soluble, non-resorbable, hydrophilic, easy to prepare and place, needs much less time for setting, produces a tighter seal and has greater radiopacity.[24]
Due to its improved material properties, Biodentine has a distinct advantage over its closest alternatives in treatment of teeth with open apex.[24] The tag like structures within the dentinal tubes may be responsible for adhesion of biodentine with the dentinal tubes through micromechanical connection.[25]
The results of the present study showed that complete obturation of the root canal with MTA and BIODENTINE may cause a tendency to fracture [Figure 5] and [Figure 6]. Therefore, MTA and Biodentine may be safely used for performing an apical barrier between 3-mm and 6-mm thick in immature teeth.
Figure 6: Intragroup comparison between fracture resistance of biodentine subgroupsBecause the use of AH 26 plus +gutta-percha increases the fracture resistance of instrumented root canals, the use of gutta-percha could be recommended to fill the remaining part of the canal.[26]
ConclusionWithin the limitations of this study, the findings of current research suggest that biodentine and MTA apical plug could be placed into the root canal up to 6-mm length, if required, during the single-visit treatment of immature teeth without adversely affecting the resistance of tooth structures.
Acknowledgment
We would like to thank Vasantdada Patil Dental College and Hospital for letting us conduct our study under supervised guidance. We also thank Praj Metallurgical Lab, Pune, for giving us unbiased result for the study conducted.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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