|Year : 2010 | Volume
| Issue : 2 | Page : 75-81
Evaluation of the sealing ability of bone cement as furcation perforation repair material when compared with mineral trioxide aggregate and calcium phosphate cement: An in-vitro study
Rashmi Chordiya1, Hemalatha Hiremath2, Sandeep Metgud3, Anant Heda4
1 Department of Conservative Dentistry and Endodontics, S.D. Dental College, Parbhani, India
2 Department of Conservative Dentistry and Endodontics, Sri Aurobindo College of Dentistry, Indore, India
3 Department of Conservative Dentistry and Endodontics, Pacific Dental College, Udaipur, India
4 Department of Conservative Dentistry and Endodontics, Aditya Dental College, Beed, India
|Date of Web Publication||20-Apr-2012|
S. D. Dental College, Parbhani, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: This study was undertaken to compare the sealing ability of bone cement as furcation perforation repair material when compared with mineral trioxide aggregate and calcium phosphate cement. Materials and Methods: A total of 70 sound mandibular molars were selected for this study. The sample teeth were randomly divided into five groups: group I - n=20, perforation repair material used, mineral trioxide aggregate; group II - n=20, perforation repair material used, calcium phosphate cement; group III - n=20, perforation repair material used, bone cement; group IV - positive control, n=5, the furcation were not repaired with any material; group V - negative control, n=5, furcation area intact, no perforation done. The teeth were immersed in silver nitrate solution for 2 hours and then rinsed with photographic developer solution for 6 hours. They were then sectioned in a longitudinal direction and examined under a stereomicroscope. In each section the actual values of dye leakage were calculated from outer margins of perforation to the level of pulpal floor and were then subjected to statistical analysis. Results: An unpaired 't' test revealed that different groups exhibited significantly different dye penetrations (P<0.01). Conclusion: Furcation perforation repaired with MTA showed minimum microleakage (mean 54.5%), calcium phosphate cement showed maximum microleakage (100%), and bone cement showed moderate dye leakage (87.8%).
Keywords: Bone cement, calcium phosphate, microleakage, mineral trioxide aggregate, perforation repair
|How to cite this article:|
Chordiya R, Hiremath H, Metgud S, Heda A. Evaluation of the sealing ability of bone cement as furcation perforation repair material when compared with mineral trioxide aggregate and calcium phosphate cement: An in-vitro study. J Int Clin Dent Res Organ 2010;2:75-81
|How to cite this URL:|
Chordiya R, Hiremath H, Metgud S, Heda A. Evaluation of the sealing ability of bone cement as furcation perforation repair material when compared with mineral trioxide aggregate and calcium phosphate cement: An in-vitro study. J Int Clin Dent Res Organ [serial online] 2010 [cited 2019 Sep 21];2:75-81. Available from: http://www.jicdro.org/text.asp?2010/2/2/75/95264
| Introduction|| |
In endodontic practice procedural accidents are encountered that will affect the prognosis of the root canal treatment. One of these procedural accidents is endodontic perforation. 
Perforations in the furcation area have the worst prognosis. Iatrogenic perforations in the furcation area may occur due to a number of causes like misdirection of bur on attempting to gain access to pulp chamber, during placement of posts and pins, or when trying to locate calcified pulp chambers and canals. ,
Traditionally, perforations have been treated nonsurgically in a similar way to apical closure of immature apices, using the mineralization potential of calcium hydroxide. 
The nonsurgical coronal treatment approach involves the immediate placement of a repair material into the perforation to avoid potential bacterial infection of the wound site. ,
Various materials are used for the repair of the perforations and they include plaster of paris fixed with zinc phosphate cement, indium foil, copper plus amalgam, amalgam alone, calcium hydroxide, Teflon disk, Gutta percha, chloroform softened Gutta percha, platinum sheet, lead disks, Cavit, glass ionomer, tricalcium phosphate, demineralized freeze dried bone, hydroxyapatite, dentine chips, AH26 root canal sealer, and MTA. The biocompatibility, sealing ability and control of the repair materials are major considerations for repair of the furcation perforation since the perforation can be considered a bottomless pit in which the extrusion of the repair material into the periodontal space is common. This can again lead to severe damage of periodontal tissues. 
A study was conducted to compare the sealing ability of mineral trioxide aggregate, calcium phosphate cement, and bone cement in furcation perforation repair.
| Materials and Methods|| |
The study samples comprised 70 human extracted permanent mandibular molars. The teeth were noncarious with nonfused and well-developed roots. The teeth were cleaned by placing in a 3% solution of sodium hypochlorite and then were washed with water.
The 70 teeth were randomly divided into 5 groups.
The groups with the types of the restoration for perforation repair in the furcation area were as follows:
- Group I: n=20, furcation perforation repair material used - mineral trioxide aggregate
- Group II: n=20, furcation perforation repair material used - calcium phosphate cement
- Group III: n=20, furcation perforation repair material used - bone cement
- Group IV: Positive control - n=5, the furcation were not repaired with any material
- Group V: Negative control - n=5, furcation area intact, no perforation done.
The access cavity preparation was done on all the three experimental groups and both the control groups. The pulp chamber was debrided of pulp tissue remnants and debris. Canals were then cleaned and shaped using hand and Rotary ProTaper NiTi files (Dentsply, Switzerland).
Then the teeth were obturated using 6% Gutta percha points. External surfaces of roots were covered with two coats of nail varnish.
Perforations were created at pulpal floor of each tooth centered in both the buccolingual and mesiodistal planes using round diamond point (BR-41, Mani, Japan).
Teeth were then inserted approximately to the level of the cemento-enamel junction into flower arrangement sponge with normal saline solution. Each repair material was mixed according to the manufacturers' instructions and was packed into the perforation defect to the level of the pulpal chamber floor.
The materials were then allowed to set and access cavities were sealed with IRM (Dentsply) and covered with two layers of varnish. Teeth were left in moist sponge for 24 hours till the complete set of the repair material.
The teeth were then removed from moistened sponge and cleaned with cotton pellets and were then immersed in a silver nitrate solution (50%, by weight) for 2 hours and then rinsed with a photographic developer solution (Premier, NM Pvt. Ltd., India) for 6 hours. They were then sectioned bucco-lingually in a longitudinal direction with a Diamond Saw (Leco Corp., USA) and finishing of the samples was done with Carborundum Powder (Mesh 300).
These sections were examined under Stereomicroscope (Leica) connected to a computer and photographed at a magnification of 20, in order to see the silver nitrate dye penetration in the area between dentinal walls and restorative material [Figure 1].
In each section the actual value of dye leakage was calculated from outer margins of perforation cavity to level of pulpal floor [Figure 2].
The maximum dye penetration along the buccal and lingual walls of either the mesial or distal section was recorded using the Image Analysis Software System (SIS, Germany).
These various values were then subjected to statistical analysis.
| Results|| |
The results of the study were as follows: [Table 1] shows the percentage of dye penetration in groups I-III. [Table 2] shows the length of dye penetration from the apical end of the perforation (L1) and the total length of the perforation (L2) in various specimens belonging to groups I-III.
An unpaired 't' test revealed that different groups exhibited significantly different dye penetrations (P<0.01).
Furcation perforation repaired with MTA group I showed minimum microleakage (mean 54.5%), group II calcium phosphate cement showed maximum microleakage (100%) and group III bone cement showed moderate dye leakage (87.8%). Group IV samples which comprised five teeth which acted as positive control showed complete dye penetration. Group V samples which comprised five teeth which acted as negative control showed no dye penetration.
| Discussion|| |
Endodontic cases are increasing in complexity to a considerable degree. Cases are managed now that, only a decade ago, would have been thought to be hope1ess. This has encouraged dentists to undertake therapy in more and more complicated cases. But, unfortunately, some of the teeth become involved in procedural misadventures - one of the most aggravating of which is the operational perforation.
Surgical repair for furcation perforations is not recommended because the area is usually surgically inaccessible, especially if the perforation is lingually situated in a mandibular molar, or if it is located in trifurcation area of a maxillary molar. Also, the surgical approach will usually lead to chronic pocket formation and periodontal furcation involvement. 
The present study was conducted to compare the sealing ability of mineral trioxide aggregate, self-setting injectable calcium phosphate cement, and bone cement when used to repair perforations in the furcation area.
Mineral trioxide aggregate (MTA) developed by Loma Linda University is a relatively new material that is being successfully used to repair perforations. MTA has a high pH (approximately 12.5)  The antibacterial effect of MTA could be because of its high pH  or release of some diffusable substance(s) into the growth medium. 
MTA shows very good biocompatibility and low mutagenic effect.  A surprising finding in histological sections is the deposition of cementum on its surface.  The sealing ability of MTA has been examined in dye leakage studies,  bacterial penetration,  and with use of fluid filtration system.  An in vitro study was done by Payman A‚ Mehrvarzfara et al., to assess the sealing ability of MTA, Geristore® , and amalgam with and without Bioglass as a matrix used to repair furcation perforations in mandibular molars by using dye penetration. They concluded that MTA and Geristore® have shown acceptable sealing ability in furcal perforation in comparison to amalgam, while Bioglass as a matrix beneath them had reduced their sealing ability.  A series of cases wherein furcal perforation was repaired using MTA was reported by Pace et al. They concluded that MTA without matrix provides an effective seal of root perforations and clinical healing of the surrounding periodontal tissue.  A long-term study also showed normal tissue architecture adjacent to the repair site with MTA.  From all these studies, it seems that MTA provides a better seal than other commonly used restorative material, such as amalgam, IRM, and super-EBA. These findings are in agreement with our findings. One reason for the very good sealing ability of MTA, when used in furcation perforation repair, is the excellent adaptation of the material to external margins of the perforation cavities.
The second group used in the study is calcium phosphate cement. The material is biocompatible, nontoxic, noncarcinogenic, and completely resorbable. It also has also been proved to have osteogenic properties. Apart from this it is easily sterilizable and has good handling characteristics, is inexpensive and also has antibacterial property, which is attributed to its high pH in the order of 12. The lack of viscous flow limits makes it difficult to transfer the cement using a syringe or a Messing Gun. The other problem is the washing out of the unset cement. The cement has limited cohesive property and if exposed to an aqueous environment, it is likely to crumple without setting. Due to this washout effect the cement may fail at the moist or bleeding site (e.g., furcation perforation or extraction socket). 
A cement formulation devoid of these problems has been developed in India by Sree Chitra Thirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
The new indigenous formulation (injectable calcium phosphate cement) has viscous and cohesive properties, which is achieved by incorporating a gelling agent. The ratio of gelling agent is optimized to 2% w/w. The setting time was found to be approximately 20 minutes. The compressive strength was observed to be 11.12 Mpa, which is in the range of trabecular bone. The cement also passed the biocompatibility-screening test (hemolysis and cell culture cytotoxicity test).
The injectable calcium phosphate cement formulation is observed to act as a cohesive and a viscous mass. When the cement was put in water or aqueous media, the mass stayed together without displacing. The cohesive property makes it suitable to seal a bleeding perforation site. The property also imparts high surface tension to the mixed cement. Therefore extrusion through the perforation is limited.  It has been shown to be highly compatible with hard and soft tissues. 
In our study, injectable calcium phosphate cement which was used to repair furcation perforation was inefficient since the material was partially washed away and the silver stain had entered massively into whole perforation cavity. This is in accordance with the study by Tsatsas et al.  where similar results were obtained with tricalcium phosphate.
Another material that may potentially provide the necessary properties for furcation perforation repair is bone cement.
Bone cement (CMW, DePuy, Johnson and Johnson, England) is common in the practice of orthopedic surgery, especially in artificial hip replacement. The material is packaged as a powder (polymethylmetacrylate polymer, methyl methacrylate-styrene-copolymer and barium sulfate) and a liquid (methyl methyl methacrylate monomer) that are mixed at the time of application.  The bone cement is said to exhibit low cytotoxicity and the bone cement powder was found to be nontoxic in nature.  It exhibits excellent biocompatibility thus may allow for tissue reattachment. In addition, bone cement tolerates a moist environment very well. Blood contamination of bone cement resulted in a slight decrease in shear strength and no difference in mechanical penetration of the cement into the bone-bone cement interface.  These characteristics potentially make it a suitable and desirable perforation repair material.
Badr conducted a study comparing the marginal adaptation and cytotoxicity of bone cement compared with amalgam and mineral trioxide aggregate as root-end filling materials. He concluded that both bone cement and MTA exhibited a better adaptation to the dentinal walls than that of amalgam. Also, the cytotoxicity testing showed that bone cement had a comparable cytotoxic effect on fibroblast cells with MTA; both root-end filling materials showed less cytotoxicity than that of amalgam. 
The present study gives comparable results as study by Holt and Matthew  with dye leakage of Bone cement (87%) intermediate to MTA and calcium phosphate cement for repair of perforation in the furcation area.
According to Tsatsas et al. the silver staining technique was used to study the sealing ability of restorative materials. This method was selected for the following reasons. Firstly, silver stain is not affected by the high pH of MTA and secondly silver nitrate is not hydrophilic in nature as are the regular dye markers (basic fuchsine).  In addition, the method uses a developer to mark the silver grains, which has a high molecular weight and similar size to that of bacteria. There may thus be a correlation between the calculated silver penetration and the penetration ability of the bacteria per se.
All teeth were painted with coat of nail polish to prevent dye penetration into lateral and accessory canals especially in furcation area. Gutman, in his study on furcation region of permanent molars, had reported patency and ability of fluid to pass through accessory canals in furcation.  All the materials used in this in vitro study were tested under similar conditions and therefore the material showing the least leakage may be the material of choice for clinical applications.
Thus MTA proves itself as a perforation repair material due to its better sealing ability and at the same time ability to stimulate tissue repair. Though there are various studies on MTA as furcation perforation repair, our study is unique in assessing these three cements as furcation perforation repair materials. Additional in vivo and in vitro tests and clinical trials are desirable in order to elucidate the effectiveness of the perforation repair materials.
| Conclusion|| |
Perforation defects have been repaired with different materials with varying degrees of success.
In the present in vitro study, dye leakage was used as a criterion to evaluate the sealing ability of three different materials for repair of furcation perforation.
Following is the conclusion derived from the recent study:
MTA with its added properties like biocompatibility and ability to allow regeneration of hard tissues may improve the prognosis of furcation perforation defect.
- The mineral trioxide aggregate showed the least microleakage.
- Calcium phosphate cement showed the maximum microleakage.
- Bone cement showed moderate microleakage.
The self-setting injectable calcium phosphate cement with its properties of biocompatibility and osteoconduction may be used as a barrier material and not a repair material for furcation perforations.
Bone cement may show a promise as a furcation perforation repair material due to its biocompatibility and ability to tolerate moist environment.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]