Relating the marginal fit of the castings to the accuracy of the impressions made from laminated hydrocolloid impression technique: a comparative study.
OBJECTIVE
Relating the marginal fit of the castings, to the accuracy of the impression produced using laminated hydrocolloid impression technique, alginate and double-mixed polyvinyl siloxane. Basic objective of the study is to check the feasibility of the use of laminated hydrocolloid impression technique in the fixed partial denture.


METHODS
The precisely machined metal die was designed to simulate standard complete metal crown preparation. The preparation was mounted on cylindrical base of 20 mm length and diameter of 10 mm. Seven impressions were made from the each impression material onto the metal die, and total 21 impressions were obtained from all three impression materials, which were poured by the die stone, and stone die was prepared. Wax patterns were fabricated on stone dies obtained from each impression and then casting was done. All the castings were checked for the marginal fit on metal die after applying a uniform standardized load of 30 pounds using measuring microscope.


RESULTS
Result revealed that the marginal fit of the castings obtained from group II (laminated hydrocolloid technique) and group III (double-mix polyvinyl polysiloxane) did not show the significant difference between the two of them. Marginal gap of the castings obtained from group I are significantly greater in comparison to the castings obtained from groups II and III (p > 0.01).


CONCLUSIONS
Group II (laminated hydrocolloid technique) impression material may be the choice of many clinicians over group III (double-mix polyvinyl polysiloxane) impression material. Group I (alginate impression material), though very cost-effective and easy to handle may not able to produce accurate results.


CONCLUSIONS
The study gives overview of the best impression material that can be used clinically. Laminated hydrocolloid technique is the technique of choice.
Department of Prosthodontics, Vaidik Dental College and Research Centre, Daman and Diu, India. drmanish29@radiffmail.com
Manish R
MR
Sinha
Bhavana
B
Thakur
Ajay
A
Gaikwad
Lalitkumar Dnyandeo
LD
Chaudhari
Adwait
A
Kulkarni
Harshal
H
Kulkarni
D000464:Alginates; D000704:Analysis of Variance; D003102:Colloids; D003442:Crowns; D003735:Dental Casting Technique; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D003830:Denture, Partial, Fixed; D061827:Dimensional Measurement Accuracy; D006801:Humans; D011145:Polyvinyls; D012833:Siloxanes; D018709:Statistics, Nonparametric
D000464:Alginates; D003102:Colloids; D003760:Dental Impression Materials; D011145:Polyvinyls; D012833:Siloxanes; C034183:vinyl polysiloxane