|Year : 2009 | Volume
| Issue : 2 | Page : 65-75
Perforation repair with artificial floor technique - A microleakage study
Pradeep Chaudhari1, Vasundhara Shivanna2
1 Professor, Department of Conservative Dentistry & Endodontics, B. V. P. Dental College and Hospital, Pune, India
2 Professor & H.O.D., Department of Conservative Dentistry & Endodontics, College of Dental Sciences, Davangere, Karnataka, India
|Date of Web Publication||4-Mar-2011|
Professor, Department of Conservative Dentistry & Endodontics, B. V. P. Dental College and Hospital, Pune
Source of Support: None, Conflict of Interest: None
| Abstract|| |
In endodontic practice one of the most common procedural accident is furcation perforation. Many materials and techniques have been tried to repair the furcation perforation. The purpose of this study is to evaluate the effect of calcium sulfate and hydroxylapatite matrix on the sealing ability of resin modified glass ionomer cement to repair the furcation perforation. The result of the study showed that the microleakage was least when perforation was repaired with resin modified glass ionomer cement over hydroxylapatite used as an internal matrix. And it was maximum when perforation was repaired with resin modified glass ionomer cement without any internal matrix material.
|How to cite this article:|
Chaudhari P, Shivanna V. Perforation repair with artificial floor technique - A microleakage study. J Int Clin Dent Res Organ 2009;1:65-75
|How to cite this URL:|
Chaudhari P, Shivanna V. Perforation repair with artificial floor technique - A microleakage study. J Int Clin Dent Res Organ [serial online] 2009 [cited 2019 Feb 23];1:65-75. Available from: http://www.jicdro.org/text.asp?2009/1/2/65/77281
| 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. 
Artificial communication between the root canal system and supporting tissues of the tooth lowers the prognosis of endodontic treatment. Ingle et al have found that the second most common reason for failure associated with endodontic treatment is root perforation. Perforation of the floor or wall of the pulp chamber or of the root occurs as a result of a number of causes :-
- Misdirection of bur in attempting to gain access to the pulp chamber.
- During the placement of posts and pins.
- Failure to follow the apical curvature during root canal instrumentation.
Due to the perforation bacterial infection can occur which leads to gingival down growth of epithelium into the perforation area, inflammation, bone resorption and/or necrosis and eventual loss of the tooth. Repair of a perforation without periradicular inflammation may take place provided infection is avoided and asepsis is maintained during treatment. 
The correction of furcation perforation can be achieved using intracoronal or surgical approach  . The non-surgical coronal approach involves the immediate placement of a repair material in the perforation to avoid potential bacterial infection of the wound site.  The major difficulty with conventional repair procedures is the extrusion of the filling material into the periodontal space,and interference with periodontal reattachment.  Materials like Cavit, Zinc phosphate cement, zinc oxide eugenol, calcium hydroxide, gutta percha, amalgam, indium foil, dentin chips are used to manage furcation perforation. Recently calcium sulfate and hydroxylapatite have shown the occurence of bone repair. These materials are stable, biocompatible, readily available, easily sterilized and its rapid rate of resorption coincides with the rate of new bone growth. 
The purpose of this study was to evaluate the effect of calcium sulfate and hydroxylapatite when used as an internal matrix on the sealing ability of resin modified glass ionomer material to repair furcation perforation.
| Aim|| |
To evaluate the effect of calcium sulfate and hydroxylapatite matrix on the sealing ability of a resin modified glass ionomer material to repair the furcation perforation.
| Materials and Method|| |
Selection of Teeth
The study samples comprised of 55 recently extracted mandibular molars with nonfused well developed roots. These teeth were cleaned by placing them in a 5% solution of sodium hypochlorite for 15 minutes and then were washed with tap water.
Out of the 55 teeth, 45 teeth were randomly divided into 3 groups of 15 teeth each. The remaining 10 teeth were randomly divided into 2 groups of 5 teeth each. The following were the groups along with types of restoration.
Group I: Furcation perforation repaired with resin modified glass ionomer cement only.
Group II: Furcation perforation repaired with medical grade calcium sulphate as an internal matrix and resin modified glass ionomer cement over it.
Group III: Furcation perforations repaired with hydroxylapatite as internal matrix and resin modified glass ionomer cement over it.
Group IV: These teeth served as positive controls. The teeth were prepared in the same manner as the experimental groups but received no filling.
Group V: These intact teeth with out perforation served as negative controls.
Access openings were prepared using a#4 round bur in a high speed handpiece with water coolant in the experimental group of 45 teeth. Perforations were made in the pulp chamber floor using a #2 round bur in a low speed handpiece. Teeth were rinsed with water and dried with oil-free air. A moist cotton pellet was placed between roots in the furcation area, and the teeth were kept in an incubator at 37º C for 24 hours.
| Restoration Procedure|| |
The perforations in the specimens of Group I were repaired with a resin modified glass ionomer only. This material was mixed according to manufacturer's instructions. The material was allowed to flow apically into the perforations and cured when it had sealed the apical end of the defect. Two additional incremental layers were applied and light cured.
The perforations in the group II were repaired with medical grade calcium sulfate as an internal matrix under glass ionomer cement. Calcium sulfate powder was placed into the moist perforation with amalgam carrier. Successive amount of powder was added until the moisture present from the cotton pellet was saturated with powder. Calcium sulfate was then condensed with a finger plugger. After the setting of calcium sulfate, dentin surface was prepared using a #33 bur to make a small cavity within the calcium sulfate floor.
This small cavity was cleaned with water spray and dried with oil-free air. The resin modified glass ionomer was then applied into the perforation as in Group I.
The perforation defects in specimens of Group III were repaired using hydroxylapatite as an internal matrix under glass ionomer cement. Hydroxylapatite was mixed in a sterile plastic well and placed into the perforation with a plastic instrument and condensed with a finger plugger. After setting of hydroxylapatite, dentin surface was prepared using a #33 bur to make a small cavity within hydroxylapatite floor. The cavity was cleaned with water spray and dried with oil free air, followed by application of the resin modified glass ionomer over the hydroxylapatite matrix in the same manner as in group l.
Experimental teeth were handled directly after removal from the incubator and the canal orifice was protected by insertion of a suitable size file into the canal during perforation repair. The pulp chamber and access preparations of experimental teeth were filled with composite resin.
All teeth were painted with nail polish except near the perforation in the furcation area and then submerged in 2% methylene blue dye for 2 weeks at room temperature. After removal from the dye, the teeth were washed thoroughly in tap water and sectioned through the repaired perforation parallel to the long axis of the tooth, with diamond disc.
Sections were examined under stereomicroscope to evaluate dye penetration. Every sample was measured for linear dye leakage. Length of perforation was measured from the pulp chamber floor to the apical end of the perforation. Leakage was measured from the apical level of repair material to the coronal end of the perforation walls. The length of repair material was measured from the floor of the pulp chamber to the coronal end of the matrix material. Percentages of dye penetration in relation to the occupied walls and sealing ability of the materials were calculated by using the following mentioned formulae.
| Formulae|| |
One way ANOVA revealed that different groups exhibited different dye penetration (F:6.86, P<0.01) and different sealing ability (F:33.6, P<0.01). In order to assess which group differs significantly from others, Duncan's Multiple Range Test was used.
Furcation perforation repaired with resin modified glass ionomer cement showed maximum microleakage (mean 60.87%) and minimum sealing ability when compared to other two groups. This value was significantly higher (P<0.0l) than that of furcation perforation repaired with calcium sulfate and resin modified glass ionomer cement. It is also significantly higher (P<0.0l) than that of furcation perforation repaired with hydroxylapatite and resin modified glass ionomer cement.
Furcation perforation repaired with calcium sulfate and resin modified glass ionomer cement showed less microleakage (mean 32.85%) and more sealing ability when compared to furcation perforations repaired with resin modified glass ionomer cement only. And this value was significantly higher (P<0.01). But it showed more microleakage and less sealing ability when compared to furcation perforation repaired with hydroxylaptite and resin modified glass ionomer cement. This value was not significant statistically.
Furcation perforation repaired with hydroxylapatite and resin modified glass ionomer cement showed minimum microleakage and maximum sealing ability when compared to other two groups. This value was significantly higher (P<0.01) than that of furcation perforation repaired with resin-modified glass ionomer only, but it is not significant when compared to furcation perforation repaired with calcium sulfate and resin modified glass ionomer cement.
| Discussion|| |
Endodontic perforations are artificial openings in the root canal system that result in a communication between the root canal and periodontal tissues. 
A root perforation can be defined as, "An artificial opening in a tooth or its root created by boring, cutting or pathological resorption which results in communication between the root canal and periodontal tissues". The most common cause of root perforation is procedural accident which can occur as a result of misdirected bur during access preparation or during preparation of a post space. In addition excessive flaring of cervical portion of curved roots in molars can also cause lateral root perforations.
Endodontic perforation definitely effects the outcome of the treatment and thus the prognosis of the tooth. Various surgical and non-surgical means have been proposed to treat the defect. Although root perforations may be repaired surgically, it often leads to: Loss of attachment, Chronic pocket formation and Periodontal furcation involvement.
Glass Ionomer Cement a hybrid of silicate and zinc polycarboxylate was introduced by Wilson and Kent in 1970s, it has various advantages like chemical adhesion to tooth structure, excellent biocompatibility and anticariogenicity. With all its advantages, it just took some time for this material to be used for sealing perforation. The advent of light cured glass ionomer which is less sensitive to moisture replaced the conventional glass ionomer cement for not only restorative purpose, but also to seal the perforations. Apart from the ability of light cure glass ionomer cement to command set, bond to dentin and release of fluoride, like conventional glass ionomer cement it is also biocompatible. 
The major difficulty with non-surgical repair even in case of proper seal is the extrusion of filling material into the periodontal ligament space that might interfere with periodontal ligament reattachment. Reattachment to materials like amalgam, gutta percha, or calcium hydroxide does not occur. The concept of internal matrices was developed in an attempt to control the extrusion of filling material into the periodontal ligament space. The matrix was suggested for use under repair materials such as glass ionomer cement to prevent their extrusion. However the effect of this matrix on sealing ability of glass ionomer cement is yet to be known. Because the matrix material cannot be removed after placement, it must satisfy the criteria for an implant material. It must be biocompatible and should not produce an inflammatory response. It must be sterile or capable of being sterilized, able to be manipulated within the root canal system and also stimulate bone formation. Materials available in dentistry that offer these properties are freeze dried bone, demineralized bone and calcium phosphate materials like tricalcium phosphate and hydroxylapatite.
The medical grade calcium sulfate commonly known as Plaster of Paris has been suggested for the treatment of root perforations. It is a safe, absorbable, moldable material that is easy to handle and less expensive. It aids in guided tissue regeneration and excludes epithelial tissues from the sites of bone formation. It also has been advocated and shown to allow bone regeneration in clinical trials. It is readily available and easily sterilizable. Plaster of Paris proved to provide a good barrier against extrusion of the repair materials when it was used to repair furcation perforations in vitro. Andeeman indicated that Plaster of Paris when placed in periodontal ligament defects was able to regenerate new alveolar bone. These properties have prompted the study of Plaster of Paris as a repair material for the periodontal ligament defect of furcation perforation.
Hydroxylapatite, chemically Ca 10 (P04) 6 (OH) 2 has been researched extensively for use in oral surgery and periodontal procedures. It has also been described as a biological internal matrix to control the extrusion of the filling material into the periodontal ligament area and was found to be biocompatible, nontoxic and osteoconductive. It has also been used as coatings for implants and bone grafting. The material has a crystalline physical texture similar to sand. The physical and chemical properties are similar to enamel and bone. Recently MTA is also tried as a matrix material to create a artificial floor which requires further research.
In this study the Group I where light cured glass ionomer cement was used to repair the furcation perforation without any matrix showed highest degree of dye penetration, when compared to Group II and Group III where perforations were repaired with light cured G.I.C. over calcium sulfate and hydroxylapatite as an internal matrix respectively. The difference was statistically significant (P<0.05) in both the cases.
This result is in agreement with study done by Hatem A.Alhadainy (1998).  In his study furcation perforations were repaired using only vitrebond, calcium sulfate and vitrebond, hydroxyapatite and vitrebond as sealing materials.
The probable causes for more dye penetration when glass ionomer cement was used alone without matrix could be as follows.
- The presence of moisture from the cotton pellet which was kept in between the roots to simulate conditions of oral environment may adversely affects the sealing ability of the glass ionomer cement. 
- As flow of glass ionomer cement is less, it might have not filled the defect completely. The materials placed into the furcation should have sufficient flow to fill and seal the apical ends of the perforations. 
Among Group II (Calcium sulfate) and Group III (Hydroxylapatite) where perforations were repaired with light cured glass ionomer cement with matrix of calcium sulfate and hydroxylapatite respectively, Group II showed more dye penetration when compared to Group III specimens. However, the difference was not statistically significant.
This result is in agreement with study conducted by Hatem A.Alhadainy and Ali LAbdalla in 1998. 
The probable causes for more leakage in Group II (Calcium sulfate) specimen as compared to Group III specimen (Hydroxlapatite) could be ;
- The presence of Plaster of Paris debris on the tooth surface may adversely affect the adhesion of glass ionomer cement to the tooth surface which inturn may attribute to more microleakage ,,.
- Flow of restorative material is a critical factor in reducing the microleakage around a furcation perforation. Plaster of Paris debris may effect the flow of light cured glass ionomer material  .
In 1998 Hatem A.Alhadainy and Van T.Himel  conducted in vivo study to evaluate hydroxylapatite based material and calcium sulfate where each was used under a resin modified glass ionomer cement to repair furcation perforations, the results showed highest radiographic success with hydroxylapatite based material, this was followed by calcium sulfate and glass ionomer.
The Group V specimens (negative control) i.e. specimens without perforation showed no microleakage while Group IV (positive control), where in the perforations were not sealed (Group IV) showed maximum microleakage. These findings are in agreement with other studies conducted by Hatem A.Alhadainy et al  in 1998 and Manu Mittal et al  in 1999.
In their studies specimen without perforation (negative control) showed no microleakage whereas specimens (positive control) where in perforations were not sealed showed maximum microleakage.
This in vitro study demonstrates more microleakage in specimens where the perforations were repaired only with glass ionomer cement without matrix material than specimens where the perforations were repaired with calcium sulfate and hydroxylapatite as a matrix below glass ionomer cement. However, this study being an in vitro study did not simulate the oral environment. The oral conditions especially the contamination of the site while repairing perforations are different. Other conditions like periodontal status, gingival condition and oral hygiene may also affect the results. Therefore the results obtained from this in vitro study may differ, so further long term clinical studies should be conducted to evaluate the efficacy of the sealing materials.
This study concludes:
[Figure 1],[Figure 2]
- The microleakage was least when perforation was repaired with resin modified glass ionomer cement over hydroxylapatite used as an internal matrix.
- The microleakage was maximum when perforations were repaired with resin modified glass ionomer cement without any matrix material. Perforation repaired with resin modified glass ionomer cement over calcium sulfate as an internal matrix material showed more microleakage than the hydroxylapatite as an internal matrix. However, the difference was not statistically significant.
- Long term in vivo studies are required before these materials can be recommended for use as perforation repair material.
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[Figure 1], [Figure 2]