Evaluation of matrix metalloproteinase and cysteine cathepsin activity in dentin hybrid layer by gelatin zymography.
OBJECTIVE
The aim of this study was to comparatively assess the gelatinolytic activity of matrix metalloproteinases(MMPs) and Cysteine Cathepsins (CCs) in the adhesive interface using etch and rinse adhesive at different time intervals using zymographic technique.


METHODS
Twenty freshly extracted non-carious human third molars were used in this study. Occlusal surfaces were ground flat and 1mm thick horizontal dentin slabs were obtained from each tooth using a diamond disc. The dentin surface was polished with 600-grit silicon-carbide paper. Five out of 20 samples were directly pulverized. In the remaining fifteen samples, the dentin was etched and adhesive was applied and light cured according to the manufacturer's instructions. A 1mm thick flowable composite was build up and light cured. Bonded specimens were cut vertically into 3 to 4 dentin slabs by means of diamond disc to expose the adhesive/dentin interfaces. These were then ground down to 500 µm thick resin-dentin interface using a hard tissue microtome. These sections were then pulverised into powder. Following this, every five samples were subjected to zymographic analysis after 1 day, 7 days and 21 days.


RESULTS
Zymograms showed clear, thicker bands on all three isoforms in the etched samples compared to control samples at 1st and 7th day intervals and became inactive at 21st day for all three isoforms. MMP 9 activity was relatively higher when compared to CCs and MMP 2.


CONCLUSIONS
Etch and rinse adhesive activated MMPs and CCs within the hybrid layer that remained active till 7th day and no gelatinolytic activity was found on 21st day and MMPs are more active compared to CCs and MMP-2.
Department of Conservative Dentistry and Endodontics, SRM Dental College, Chennai, Tamil Nadu, India.
Sekar
S
Mahalaxmi
Department of Conservative Dentistry and Endodontics, SRM Dental College, Chennai, Tamil Nadu, India.
Manavalan Madhana
MM
Madhubala
Department of Dentistry, Chennai Medical College Hospital and Research Centre, Trichy, Tamil Nadu, India.
Mahendran
M
Jayaraman
Private Practitioner, Chennai, Tamil Nadu, India.
Shanmugasundaram
S
Sathyakumar
D000134:Acid Etching, Dental; D017554:Carbon Compounds, Inorganic; D002403:Cathepsins / Q000378:metabolism*; D003188:Composite Resins; D003545:Cysteine / Q000378:metabolism*; D001840:Dental Bonding; D003738:Dental Cements; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000201:enzymology*; D017220:Dentin-Bonding Agents; D005780:Gelatin / Q000378:metabolism*; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry; D017655:Silicon Compounds
D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D017655:Silicon Compounds; C111840:flowable hybrid composite; D005780:Gelatin; D002403:Cathepsins; D020782:Matrix Metalloproteinases; D003545:Cysteine; C022088:silicon carbide