6. / BRIEF RESUME OF INTENDED WORK:
6.1 Need for the study :
Advances in the health research have resulted in a major paradigm shift in the diagnosis, treatment and management of dental caries.
The most common approach for removal of caries involves use of hand instruments, low speed and high speed rotary instruments. But the fundamental drawbacks of this approach, being inherent to the technique, involves: necessity of local anesthesia, unpleasantness to the patient, and potential adverse effects to the pulp due to heat1. Furthermore, drilling results in excessive and rapid removal of affected dentin2.
The widely accepted principle of “extension for prevention” proposed by G.V.Black, in the operative treatment of carious lesion has been challenged and is now considered as too destructive method for caries removal3. The advent of adhesive restorative materials has led to the conservation of tooth structure with minimal cavity designs4.
More recently, newer techniques for removal of carious dentine have been developed in an attempt to minimize this excessive tissue loss. A chemo-mechanical (Carisolv) system has been recently developed as an option for the selective removal of infected dentin5.
However, considering the increased utilization of adhesive restorative techniques, the present study evaluates the degree of marginal leakage in cavities prepared by the chemo-mechanical method for the removal of carious tissue, and restored with different adhesive restorative materials currently employed when compared with traditional mechanical method of caries removal5.
6.2 REVIEW OF LITERATURE:
1) A comparative study5 evaluated the degree of marginal leakage in bonded restorations using mechanical or chemo-mechanical (Carisolv) removal of carious tissue. The samples were restored and subjected to thermocycling, and then exposed to dye, sectioned and qualitatively evaluated. It was concluded that the system of removal of carious tissue did not influence the results of marginal leakage at any of the cavity margins.
2) A study6 was done to investigate the nanoleakage patterns of caries affected dentin after excavation with Carisolv or conventional instruments treated with one of the three adhesive systems. Specimens were immersed in 50% silver nitrate solution, sectioned and observed in a field emission scanning electron microscope. It was observed that the silver deposition occurred along the base of the hybrid layer for all specimens. It could be seen that use of chemo-mechanical caries removal does not adversely affect the bond to caries affected dentin.
3) In another study7 was carried out in which the cavities were prepared by Carisolv and were verified as being caries free by two methods:
a) By conventional visual and tactile criteria
b) using quantative laser fluorescence- Diagnodent (Kavo) It was observed that complete removal of carious dentin with Carisolv was easy when proper instructions were followed. Cavities examined by scanning electron microscope showed good adhesion and sealing between the restorative
material and the dental hard tissues.
4) A comparative study8 was conducted to asses the marginal leakage of composite restoration following caries removal with carbide burs and Carisolv in one hundred human posterior teeth with class V caries. The specimens were thermocycled and then placed in dye. Teeth were sectioned and evaluated for marginal leakage using a stereomicroscope. It was concluded that there was no significant difference in marginal leakage between conventional and chemo-mechanical caries removal methods.
5) A study9 was carried out to determine whether shear bond strength to chemo-mechanically excavated dentin (Carisolv) differed from that of conventional caries removal (burs). Different adhesive systems were used. One hundred and twenty human molars with occlusal caries were categorized into 12 groups. Sequential caries removal was controlled with laser fluorescence. The samples were tested in a single-plane shear test assembly. The results showed differences between the bonding systems where as mode of caries removal had no consistent effect.
6) An in vitro study10 evaluated the influence of Carisolv for resin adhesion to sound human primary and young permanent dentin. The buccal surfaces of primary molars and premolars were used. Two adhesive system and resin composites were used; SE: Clearfill SE and Clearfill APX and SB: Single Bond and Z250. The microstructure of primer or etchant and Carisolv plus primer or etchant applied to dentin were evaluated by scanning electron microscope. Shear bond strengths (SBS) were tested, and the failed surfaces
were observed using scanning electron microscope. It was concluded that
the Carisolv treatment before priming significantly decreased the SBS to primary dentine in SE groups, but did not influence the SBS to permanent dentine in both SE and SB groups.
7) A study11 was carried out to compare the efficacy of Carisolv and conventional slow speed rotary instruments (burs). They selected fourteen extracted human molar teeth with deep dentin caries and no enamel coverage. The teeth were sectioned through the centre of the carious lesion. Caries in one half was removed by conventional drilling and other half was removed with Carisolv. The two halves of each tooth were processed for histological examination. The thin sections were stained and examined for the presence of bacteria under light microscope. It was concluded that the conventional rotary instrument (bur) was more effective than Carisolv in removal of carious tissue and takes shorter time.
6.3 AIMS AND OBJECTIVES OF THE STUDY:
To evaluate the degree of marginal leakage of composite resins bonded with two etch & bond dentin bonding agents and one self etching primer adhesive system, following mechanical or chemo-mechanical methods of caries removal.
B)
7. MATERIALS AND METHODS:
7.1 Source Of Data Or Materials :
60 human posterior teeth with caries not involving the pulp, extracted for periodontal reasons.
§ Carisolv kit (MediTeam Dental AB, Schweden) containing specially designed hand instruments to excavate caries.
§ Round burs
§ Caries detecting dye: Sable Seek (Ultradent)
§ Adhesive system:
a. Single bond and Z250 (3M ESPE )
b. Prime & Bond NT and Esthet X (Dentsply)
c. Unifil Bond and Solare (GC Asia)
§ Dye – Indian Ink
§ Stereomicroscope (Olympus Labovision)
7.2 METHODOLGY:
Method of collection of data :
The teeth are collected from the department of oral and maxillofacial surgery, A.E.C.S. Maaruti College of Dental Sciences, Bangalore.
Inclusion criteria:
· Posterior teeth with coronal dentinal caries not involving the pulp.
· Caries lesions with a brown to black colour and medium consistency
when tested with a sharp probe were selected.
· Teeth removed intact while extracting.
Exclusion criteria:
· Non carious teeth.
· Grossly decayed teeth.
· Teeth which fractured while extracting.
· Teeth with hard or discoloured arrested caries.
· Teeth where caries had already involved the pulp.
The surfaces of the teeth will be cleaned with scalers and a No.11 Bard Parker blade for removal of calculus and remnants of periodontal ligament. They will be stored in 2% formalin solution for 14 days, and subsequently stored in saline solution.
The teeth will be randomly divided into 6 groups. Following caries removal using one of the two experimental methods. The cavities will be restored with composite resin following manufacturers instructions.
GROUP 1 :
The carious tissue will be removed by the using excavators followed by round burs at low speed. Complete removal of carious tissue will be assessed by use of a caries detecting dye. Acid etching will be performed and Single Bond adhesive (3M ESPE) is applied following manufacturer’s instructions. The cavity will be then restored with increments of composite resin
Z250 (3M ESPE) which will be light cured.
GROUP 2 :
The carious tissue will be removed with the chemo-mechanical system (Carisolv) according to manufacturers instructions. The product will be applied until complete removal of carious tissue, as clinically demonstrated by the absence of staining of the dentinal tissue secondary to application of caries detecting dye. The tooth will then be restored with Single Bond adhesive and Z250 (3M ESPE) according to manufacturers instructions.
GROUP 3:
The carious tissue will be removed using conventional rotary instruments (burs). The adhesive system Prime & Bond NT (Dentsply) will be applied following manufacturers instructions. The cavity is then restored with composite
resin EsthetX (Dentsply ) and light cured.
GROUP 4:
In this group, chemo-mechanical system (Carisolv) will be employed for removal of carious tissue. The teeth will be restored with Prime & Bond NT and EsthetX (Dentsply) according to manufacturer’s instructions.
GROUP 5:
The carious tissue will be removed using conventional rotary instruments (burs). The adhesive system Unifil Bond (GC Asia) will be applied following manufacturer’s instructions. The cavity is then filled with composite resin Solare (GC Asia) and light cured.
GROUP 6:
In this group, chemo-mechanical system (Carisolv) will be employed for removal of carious tissue. The teeth will be restored with Unifil Bond and Solare(GC Asia) according to manufacturer’s instructions.
After completion of restorations the specimens will be kept in an incubator at 37oC for 24 hours. After finishing and polishing, the specimens will be subjected to thermocycling for 500 cycles between 5oC and 55oC with a dwell time of 30 seconds.
The entire specimen will be covered in two coats of nail varnish exposing only the restoration and two millimeters of surrounding tooth structure. The specimen is then immersed in Indian Ink for 48 hours.
Specimens will be sectioned in a buccolingual direction through the centre of the restoration and evaluated for dye penetration.
Degree of marginal leakage will be evaluated using a stereomicroscope. Scores 0-3 will be assigned as described in the table and values obtained will be subjected to statistical analysis.
Table: Evaluation of degree of marginal leakage in enamel/dentin.
Score / Degree / Marginal leakage
0 / Absent / Absence of dye at the tooth/restoration interface.
1 / Mild / Dye penetration at the tooth/restoration interface up to half of the distance between the cavosurface angle and pulpal floor.
2 / Moderate / Dye penetration at the tooth/restoration interface up to more than half of the occlusal wall in enamel and dentin.
3 / Severe / Dye penetration at the tooth/restoration interface, reaching the pulpal floor.
STATISTICAL ANALYSIS
The data will be statistically analyzed by using Kruskel-Wallis test and Mann-Whitney test.
7.3 DOES THE STUDY REQUIRE ANY INVESTIGATION OR INTERVENTIONS TO BE CONDUCTED ON PATIENTS OR OTHER HUMANS OR ANIMALS? IF SO, PLEASE DESCRIBE BRIEFLY.
NOT APPLICABLE
7.4 HAS ETHICAL CLEARENCE BEEN OBTAINED FROM YOUR
INSTITUTION?
NOT APPLICABLE
7.5 TRAIL TESTS DONE IF ANY?
YES
C)
LIST OF REFERENCES:
1. / Maragakis G. M., Hahn P, Freiburg E.H. “Chemo-mechanical caries removal: a comprehensive review of literature”International Dental Journal 2001; 51; 291-99
2. / Marquezan M, Faraco I.M., Feldens C.A., Towo M. F., Ottoni A. B. “Evaluation of the methodologies used in clinical trials and effectiveness of chemo-mechanical caries removal with Carisolv”
Brazilian Oral Research 2006; 20(4): 364-71.
3. / Banerjee. A , Watson T. F, Kidd E.A.M. “Dentin caries excavation :a review of current clinical techniques”
British Dental Journal;2000;188(9): 476-82
4. / Ziskind D, Kupietzky A, Beyth N. “First-choice treatment alternatives for caries removal using the chemomechanical method”
Quintessence International 2005;36: 9-14.
5. / Okido R.C., Martins T.M., Briso A.L.F,
“In Vitro evaluation of marginal leakage in bonded restorations, with mechanical or chemical-mechanical (Carisolv) removal of carious tissue”.
Brazilian Oral Research 2007; 21(2); 176-81
6. / Kubo S, Li H, Burrow M.F, Tyas M.J. “Nano leakage of dentine adhesive systems bonded to Carisolv treated dentin”
Operative Dentistry. 2002;27(4):387-95
7. / Yamada, Kimura Y, Hossain.M.‘‘Caries removal with Carisolv system:criteria evaluation and microleakage test’’
Journal of Clinical Pediatric Dentistry 2005; 30(2);121-26.
8. / Mousavinenasab S.M, Jafary M, “Microleakage of Composite Restorations Following Chemo-mechanical and Conventional Caries Removal”
J Dent TUMS 2004; 1 (4).
9. / Haak R, Wicht M.J, Noack M.J, “Does chemomechanical caries removal affect dentine adhesion?”
European Journal of Oral Science 2000;108: 449-55
10. / Hosoya Y, Shinkawa H, Marshall G.W.M, “Influence of Carisolv on resin adhesion for two different adhesive systems to sound human primary
dentin and young permanent dentin”
Journal of Dentistry 2005; 33; 283–91
11. / Yazici A.R, Atilla P, Ozgunaltay G, Muftuoglu S. “In vitro comparision of the efficacy of carisolv and conventional rotary instrument in caries removal.”
Jour of Oral Rehabilitation 2003; 30; 1177-82.