Comparative study of the marginal microleakage of six cements in fixed provisional crowns.
BACKGROUND
In many situations, provisional restorations require a long-term permanence in the oral cavity. During this period, the abutments need the best possible biologic and mechanical protection. In this way, the vitality of the pulp and the integrity of mineralized tissues can be preserved. The luting cement used to fix interim restorations should have good mechanical properties, low solubility, and good adhesion to resist bacterial and molecular penetration. However, because of its provisional nature, the prosthesis should be easy to remove from the abutments. These contrasting requirements may lead to a compromise in cement behavior, particularly in its mechanical properties.


OBJECTIVE
This in vitro study evaluated the marginal microleakage of 4 provisional cements, a cavity base compound and a zinc-phosphate luting cement in provisional acrylic resin crowns fixed on extracted human teeth.


METHODS
Thirty acrylic resin crowns were made and fitted on intact human premolars with the 6 cements. All restorations were applied in a standardized manner by means of an axial load of 10 kg. Specimens were thermocycled then submerged in a 5% basic fuchsin solution, then sectioned and observed under a light stereomicroscope. A 5-level scale was used to score dye penetration in the tooth/cement interface.


RESULTS
A high dye penetration in the tooth/cement interface was present in all 4 provisional cements. Microleakage existed in specimens where zinc-phosphate and cavity base compounds were used; however, it was lower than the other materials. A significant difference (P < .05) was found between zinc-phosphate and one eugenol-free cement and between cavity base and the same eugenol-free cement.


CONCLUSIONS
All materials tested demonstrated different degrees of microleakage. Zinc-phosphate and cavity base compound cements had the best sealing properties. This latter, even if conceived as a cavity base, may be considered a good provisional cement as far as microleakage is concerned.
Baldissara
P
P
Department of Prosthodontics, University of Bologna, School of Dentistry, Italy.
Comin
G
G
Martone
F
F
Scotti
R
R
D000180:Acrylic Resins / Q000737:chemistry; D001641:Bicuspid / Q000648:ultrastructure; D002126:Calcium Hydroxide / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003442:Crowns; D000044:Dental Abutments; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003763:Dental Leakage / Q000175:diagnosis*; D003764:Dental Materials / Q000737:chemistry; D003782:Dental Pulp / Q000502:physiology; D005054:Eugenol / Q000737:chemistry; D005069:Evaluation Studies as Topic; D006801:Humans; D008422:Materials Testing; D012394:Rosaniline Dyes; D012995:Solubility; D013314:Stress, Mechanical; D013816:Thermodynamics; D015034:Zinc Oxide / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
D000180:Acrylic Resins; D003738:Dental Cements; D003764:Dental Materials; D012394:Rosaniline Dyes; D005054:Eugenol; C025485:basic fuchsin; C076899:Temp-Bond; D015036:Zinc Phosphate Cement; C040408:Life (dental material); D002126:Calcium Hydroxide; D015034:Zinc Oxide