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Comparison of variation in the light curing cycle with a time gap and its effect on polymerization shrinkage, degree of conversion and microhardness of a nanohybrid composite.

Subbiya A, Pearlin Mary NS, Suresh M, Vivekanandhan P, Dhakshinamoorthy M, Sukumaran VG - J Conserv Dent (2015 Mar-Apr)

Bottom Line: Giving a time gap and distance during curing can decrease the polymerization shrinkage.Curing at 1-cm distance for 10 seconds with a gap of 10 seconds and finishing the curing cycle with 20 seconds at 0 cm proved to be an appropriate technique to reduce the polymerization shrinkage without significantly affecting the DOC and microhardness.A simple innovative modification of varying the distance of curing and a time gap in the curing cycle can decrease the polymerization shrinkage without affecting the DOC and microhardness.

View Article: PubMed Central - PubMed

Affiliation: Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India.

ABSTRACT

Background: Giving a time gap and distance during curing can decrease the polymerization shrinkage.

Aim: To evaluate the effect of time gap and distance between the curing tip and restoration on the polymerization shrinkage, degree of monomer conversion (DOC), and microhardness of a nanohybrid composite.

Materials and methods: A total of 50 standardized cylindrical specimens (Z350, 3M ESPE) were fabricated using a brass mould. The curing was done in contact with the sample surface for 20 seconds in the control group. In the four experimental groups, curing was initiated at 1-cm distance, followed by variation in the time gap and the curing cycle. The polymerization shrinkage, DOC, microhardness was calculated.

Statistical analysis: One-way analysis of variance (ANOVA) and post hoc-Dunnett test were used to analyze the data.

Results: Curing at 1-cm distance for 10 seconds with a gap of 10 seconds and finishing the curing cycle with 20 seconds at 0 cm proved to be an appropriate technique to reduce the polymerization shrinkage without significantly affecting the DOC and microhardness.

Conclusion: A simple innovative modification of varying the distance of curing and a time gap in the curing cycle can decrease the polymerization shrinkage without affecting the DOC and microhardness.

No MeSH data available.


Degree of monomer conversion FTIR spectra
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Figure 2: Degree of monomer conversion FTIR spectra

Mentions: The DOC was analyzed using Fourier Transformation Infrared Raman (FTIR) spectrometer (Thermo Scientific Inc., Waltham, USA). After 24 hours of curing, the samples were placed in the spectrometer and the post irradiation spectra were obtained [Figure 2]. Spectra were collected in the mid infrared region between 1550 and 1680/cm with 128 scans, at the range of 4000/cm.[10] The conversion of the unreacted c = c (aliphatic) to the c-c (aromatic) was measured for all the experimental groups using the formula:


Comparison of variation in the light curing cycle with a time gap and its effect on polymerization shrinkage, degree of conversion and microhardness of a nanohybrid composite.

Subbiya A, Pearlin Mary NS, Suresh M, Vivekanandhan P, Dhakshinamoorthy M, Sukumaran VG - J Conserv Dent (2015 Mar-Apr)

Degree of monomer conversion FTIR spectra
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4379658&req=5

Figure 2: Degree of monomer conversion FTIR spectra
Mentions: The DOC was analyzed using Fourier Transformation Infrared Raman (FTIR) spectrometer (Thermo Scientific Inc., Waltham, USA). After 24 hours of curing, the samples were placed in the spectrometer and the post irradiation spectra were obtained [Figure 2]. Spectra were collected in the mid infrared region between 1550 and 1680/cm with 128 scans, at the range of 4000/cm.[10] The conversion of the unreacted c = c (aliphatic) to the c-c (aromatic) was measured for all the experimental groups using the formula:

Bottom Line: Giving a time gap and distance during curing can decrease the polymerization shrinkage.Curing at 1-cm distance for 10 seconds with a gap of 10 seconds and finishing the curing cycle with 20 seconds at 0 cm proved to be an appropriate technique to reduce the polymerization shrinkage without significantly affecting the DOC and microhardness.A simple innovative modification of varying the distance of curing and a time gap in the curing cycle can decrease the polymerization shrinkage without affecting the DOC and microhardness.

View Article: PubMed Central - PubMed

Affiliation: Department of Conservative Dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Narayanapuram, Pallikaranai, Chennai, Tamil Nadu, India.

ABSTRACT

Background: Giving a time gap and distance during curing can decrease the polymerization shrinkage.

Aim: To evaluate the effect of time gap and distance between the curing tip and restoration on the polymerization shrinkage, degree of monomer conversion (DOC), and microhardness of a nanohybrid composite.

Materials and methods: A total of 50 standardized cylindrical specimens (Z350, 3M ESPE) were fabricated using a brass mould. The curing was done in contact with the sample surface for 20 seconds in the control group. In the four experimental groups, curing was initiated at 1-cm distance, followed by variation in the time gap and the curing cycle. The polymerization shrinkage, DOC, microhardness was calculated.

Statistical analysis: One-way analysis of variance (ANOVA) and post hoc-Dunnett test were used to analyze the data.

Results: Curing at 1-cm distance for 10 seconds with a gap of 10 seconds and finishing the curing cycle with 20 seconds at 0 cm proved to be an appropriate technique to reduce the polymerization shrinkage without significantly affecting the DOC and microhardness.

Conclusion: A simple innovative modification of varying the distance of curing and a time gap in the curing cycle can decrease the polymerization shrinkage without affecting the DOC and microhardness.

No MeSH data available.