ENDODONTOLOGY. CALCIUM PHOSPHATE CEMENT: A NEW SAVIOUR FOR FURCATION PERFORATION? - An in-vitro study INTRODUCTION MATERIALS AND METHODS ABSTRACT

Transcription

1 CALCIUM PHOSPHATE CEMENT: A NEW SAVIOUR FOR FURCATION PERFORATION? - An in-vitro study SANOOP GEORGE * VASUNDHARA SHIVANNA ** DHANYAKUMAR N. M. *** ABSTRACT This study was conducted to evaluate the sealing ability of a new material, self-setting injectable calcium phosphate cements in furcation perforations and compare it with light cured glass-ionomer cements and Cavit. Fifty recently extracted maxillary and mandibular molars with non-fused well developed roots were collected and intentional perforations were made in the furcation area with a bur. The perforations were repaired with calcium phosphate cement, Resin modified glass ionomer cement and cavit. These specimens were then immersed in 2% methylene blue dye. After their removal, they were sectioned and examined under stereomicroscope to evaluate dye penetration. Results demonstrated that furcation perforation repaired with calcium phosphate cement showed least micro leakage. In conclusion, calcium phosphate cement demonstrated better results than the other groups. INTRODUCTION In endodontic practice procedural accidents are encountered that will affect the prognosis of root pulp space therapy. One of these procedural accidents is endodontic perforation.the management of perforation is still a challenge in endodontics. The correction of furcation perforation can be achieved using intracoronal (non surgical) or surgical approach. The root perforation can be repaired surgically, but a furcation perforation is surgically inaccessible. Secondly, a surgical attempt will often lead to loss of attachment, pocket formation and periodontal furcation involvement. The practical method adopted to treat the endodontic furcation perforation is a non-surgical coronal approach 20 The quick sealing of the perforation and the successful healing of the region are crucial for salvaging the tooth 18. This poses stringent requirements on the properties of the sealing materials. It should be essentially biocompatible, non toxic, non carcinogenic, completely resorbable and easily sterilizable. It should also preferably be convenient to use, easy to procure and relatively inexpensive. Above all, it should provide adequate seal, non penetrable to bacteria and induce osteogenesis and cementogenesis 8. The purpose of this study was to evaluate the sealing ability of a new material, self-setting injectable calcium phosphate cements in furcation perforations and compare it with light cured glassionomer cements and Cavit. MATERIALS AND METHODS Fifty recently extracted maxillary and mandibular molars with non-fused well developed roots were collected and randomly divided into five groups of ten teeth each. GROUP I: Perforation repaired with Calcium Phosphate cement. * Professor, ** Professor, *** Professor Department of Conservative Dentistery and Endodontics, College of Dental Sciences, P.O. Box No. 327, Davangere

2 GROUP II: Perforation repaired using Resin Modified Glass Ionomer Cement. GROUP III: Perforation repaired with Cavit. GROUP IV: POSITIVE CONTROL:Perforation not repaired with any material. GROUP V: NEGATIVE CONTROL: Ten unprepared intact teeth Access cavity preparations were done on the three experimental groups and the positive controls.the pulp chamber and root canal was debrided of pulp tissue remnants and debris. Using a hand piece fitted to a drill press (to standardize perforation diameter and parallelism along long axis of tooth), perforations were made on the center of the floor of the pulp chamber using # 2 carbide round bur. A moist cotton pellet which did not act as a matrix for the repair material was placed in the furcation area to simulate wet clinical field. The perforations were repaired with the concerned repair material. The pulp chamber and access preparations of all these 4 groups were filled with visible light activated composites (Z 100, 3M). Now all the teeth in groups in I, II, III and IV are coated with two layers of nail polish except for 1-2 mms around the furcation perforation, but in group V the whole teeth was covered with nail polish. All these teeth are kept in the incubator at 37 degree centigrade for 24 hours to allow calcium phosphate cement to completely set. All the teeth were then immersed in 2 % methylene blue dye for 48 hours. After removal from dye, the teeth were rinsed in water and dried at room temperature for 24 hours. The teeth are then mounted on acrylic blocks and sectioned buccolingually with the help of diamond discs. 8 The sections were examined under stereomicroscope to evaluate dye penetration. In each section, length of the perforation wall and the filling related to each wall was measured from the pulp chamber floor to the apical end of the preparation. Leakage was measured on each wall as the amount of linear dye penetration from the apical end of the perforation to the pulp chamber floor. Dye penetration and sealing ability expressed as percentages and mean percentages are determined.multiple group comparisons were made by ONE WAY ANOVA followed by MANN WHITNEY TEST for pair wise comparisons. A p-value of less than.05 was considered for statistical significance. The percentages of dye penetrations in relation to the occupied walls and the sealing ability of the materials were calculated using the below mentioned formula 19 : FORMULAE: L3 Percentage of dye penetration = X100 L1 L2 - L3 Sealing ability = L2 L I = Total perforation length,l2 = Length of sealing material,l3 = Length of dye penetration from apical end of sealing material RESULTS Group I samples offered a mean dye penetration of 79.2% and a mean sealing ability of 44.1 %. Group II samples offered a mean dye penetration of 83.5% and a mean sealing ability of 39.6%. Group III samples offered a mean dye penetration of 90.4% and a mean sealing ability of

3 16.7% Group IV samples (positive control) showed complete dye penetration wheras,group V samples (negative control)showed no dye penetration. It revealed that group I showed least dye penetration and best sealing ability when compared to group II and group III. The difference was statistically significant between group I and III for both dye penetration (p < 0.01) and sealing ability (p < 0.001). DISCUSSION In this study, the results observed with calcium phosphate cement are similar to those reported by Chau et al. 15 Calcium phosphate cement is a mixture of two calcium phosphate compounds, one acidic and other basic. The basic calcium phosphate compound in this cement is tetra calcium phosphate and the acidic calcium phosphate compound can be either dicalcium phosphate dihydrate or anhydrous calcium phosphate. When this is mixed with an aqueous solution it sets into a hard mass, the end product being hydroxyapatite which is the mineral part of vertebrate bone 2. But one problem is the delivery of the material at the perforation site. The lack of viscous flow limits makes it difficult to transfer the cement using a syringe or a messing gun. Trying to squeeze out the cement with such a technique will push the liquidous part of the mixed cement. The other problem is the washing out of the unset cement. Due to this wash out effect the cement may fail at the moist or bleeding site 18. A cement formulation 18 devoid of these problems has been developed in India by Sree Chitra Thirunal Institute for Medical Sciences and Technology, Trivendrum, Kerala, and was used in this study. The new indigenous formulation (injectable calcium phosphate cement) has viscous and cohesive properties, which is achieved by incorporating a gelling agent 15. The ratio of gelling agent is optimized to 2 % w/w. This cement can also be applied as a paste and shaped during placement. They combine the osteocompatability and the biocompatibility of hydroxyapatite implants and mouldability of acrylic bone cements and are highly versatile in applications.the material is bio compatible, nontoxic, non-carcinogenic, and completely resorbable 8.It also has proven osteogenic properties. Apart from this they are easily sterilizable and have good handling characteristics, are inexpensive and also have anti bacterial property, which is attributed to its high ph in the order of 12. The setting time was found to be approximately 20 minutes 7. The x-ray diffraction spectrum of the cement showed similarity to that of bone mineral ( hydroxyapatite particles ).The surface micro morphology observed in SEM showed partial porosity. The compressive strength was observed to be Mpa, which is in the range of trabecular bone 7. The cement also passed the biocompatibility-screening test (hemolysis & cell culture cytotoxicity test) 8. The injectable calcium phosphate cement formulation is observed to act as a cohesive and a viscous mass. The cohesive property makes it suitable to seal a bleeding perforation site. The property also imparts high surface tension to the mixed cement 4. Therefore extrusion through the perforation is limited. Therefore superior sealing ability of calcium phosphate cement may be explained by its capacity to adhere to the canal walls. Even if the cement extruded, due to its biocompatibility, it would not possibly adversely affect the healing of the local tissues in the apical 9

4 area. In fact, calcium phosphate cement will be effective in stimulating bony repair through osteoconduction 6. COMPARATIVE STATISTICS OF SEALING ABILITY The use of calcium phosphate may therefore significantly improve the prognosis of teeth with furcation perforation though in vivo studies using animal models should be performed to confirm the biocompatibility and osteoconductive ability of calcium phosphate cement when used in furcation perforation. 9, 10 In previous studies, Alhadainy and Himel found light cured glass ionomer cements exhibited a better seal than amalgam and was superior to chemically cured glass ionomer cement.the probable cause for more dye penetration with glass ionomer cement than calcium phosphate cement could be the presence of moisture from the cotton pellet, which was kept in between the roots to simulate the conditions of oral environment 9, 15. Fig 1:Furcation perforation repaired with calcium phosphate cement Fig 2: Furcation perforation repaired with Resin modified glass ionomer cement The probable cause for the highest dye penetration when Cavit was used as a furcation perforation repair material could be that a complete operation obturation was not possible due to the dissolution and disintegration of cavit in the fluids. This was similar to the studies by Van.T.Himel et.al 40 who used it in dogs where there was disintegration of cavit due to its resorption by the bodies physiological defense mechanism. COMPARATIVE STATISTICS OF DYE PENETRATION Fig 3:Furcation perforation repaired with cavit. REFERENCES 1. Balla R, Lo Monaco C J, Skribner J, Lin L M. : Histological study of furcation perforations treated with Tricalcium phosphate, hydroxyl apatite, amalgam and Life. J Endod 1991; 17; Brown W E and Chow L C A New Calcium Phosphate Setting Cement, J. Dent. Res., 62 (1983) Cherng A M et al : Invitro evaluation of a calcium phosphate cement root canal filler/sealer. American dental association 10

5 health foundation, Paffenberger research center. National institute of standards and technology, Gaithersburg, MD20899,USA. 4. Comuzzi L, Ooms E and Jansen J A. : Injectable calcium phosphate cement as a filler for bone defects around oral implants: an experimental study in goats. Clin. Oral. Implants Res., 13(2002) Donald E.Arens, Mahmoud Torabinejad : Repair of furcal perforations with mineral trioxides aggregate. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1996; 82 : Fugikawa-K, Sugawara- A, Murai-S, Nishiyama- M, Takagi- S. Histopathological reactions of calcium phosphate cement in periodontal bone defect. Dent- Mater- J june; 14(1): Fukase-Y; Eanes-ED; Takagi-S; Chow -LC; Brown-WE. : Setting reactions and compressive strengths of calcium phosphate cements. J-Dent-Res Dec; 69(12): Gruninger.S.E. et al. : Evaluation of the biocompatibility of a new calcium phosphate setting cement. J Dent.Res ; 62 (1983) Hatem A.Athadainy and Van T.Himel : Comparison of light cured materials versus chemically cured in the repair of furcation perforation. Oral Surgery Oral Medicine, Oral Patho1og, 1993 ; 76 (3) : Hatem A.Alhadainy and Van T.Himel : Evaluation of the sealing ability of amalgam, cavit, and glass ionomer cement in the repair of furcation perforation. Oral Surg Oral Med Oral Pathol, 1993 ; 75 : Hatern A.Alhadainy : Root perforations. Oral Surg Oral Med Oral Pathol, 1994 ; 78 : Hatem A.Alhadiny and Van Himel : An in vitro evaluation of plaster of Paris barriers used wider amalgam and glass ionomer to repair furcation perforations. Journal of Endodontics, 1994 ; 20 (9) : Hatem A.Alhadainy and A.Abdalla : Artificial floor technique used for the repair of furcation perforations : A microleakage study. Journal of Endodontics, 1998 :24(1): Hong YC, Wang JT, Hong CY, Brown WE, Chow LC. The periapical tissue reactions to calcium phosphate cement in the teeth of monkeys. J Biomed- mater- res April; 25 (4): James Y.M.Chau, Jeffrey W.Hutter, et al: An in vitro study of furcation perforation repair using calcium phosphate cement. Journal of Endodontics, 1997 ; 23 (9) : Leroux- L et al. effects of various adjuvants on the injectability of calcium phosphate cement. Bone.1999 Aug;25:31S-34S 17. Mahmoud E.ElDeeb. Abbas Tabjbi, James R.Jensen : An evaluation of the use of amalgam, cavit and calcium hydroxide in the repair of furcation perforation. Journal of Endodontics. 1982; 10 (8) : Manoj Komath and P R Harikrishna Varma : Injectable Calcium Phosphate Cement for Dental Applications Indian Patent Applied Manu Mittal, Satish Chandra, Shaleen Chandra : An evaluation of Plaster of Paris Barriers used under various materials to repair furcation perforations. (In vitro study). Journal of Endodontics, 1999 ; 25 (5) : Ronald R.Lemon : Non-surgical repair of perforation defects. Dental Clinics of North America, (2) : BE PROUD TO BE A MEMBER OF THE INDIAN ENDODONTIC SOCIETY Kindly send a note with photograph of your personal achievements as well as activities and achievements of your professional Endo group in your area. Editor will be happy to publish them. - Editor 11