Effect of fluoride varnish on the retentive strength of rovisional crowns luted with various temporary cements I. Lewinstein, DMD, PhDSa Z. Daniel, DMD,b B. Azaz, DMD,” I. Gedalia, PhDd Hebrew University, Hadassah School of Dental Medicine, Jerusalem, Israel
and
The retention of temporary crowns was studied with the use of a fluoride varnish (Duraphat) combined with various temporary cements. The mixture of Duraphat varnish and cement improved retention, with the exception of Opotow cement. Applying Duraphat varnish to the tooth surface before cementation enhanced the retentive strength of Tempbond, weakened the retention of Freegenol, but had no effect on Opotow cement. A “transfer effect” was observed, inasmuch as the Duraphat varnish encouraged adherence of the cement to the tooth structure rather than to the temporary crown. (J PROSTHETDENT 1992;68:‘733-6.)
emporary cements are important in restorative dentistry because they are luting agents for treatment restorations and for final castings.l Provisional restorations occasionally function for extended periods while adjunctive treatments such as periodontics, endodontics, orthodontics, or oral surgery are being completed. Interim restorations are susceptible to secondary caries when placed for a prolonged interval. A similar phenomenon can be observed with temporarily cemented final restorations, if the interim cement dissolves. The addition of fluoride compounds to zinc oxide-eugenol (ZOE) base has been shown to increase the microhardness of the dentin without compromising the physical properties of the liners.2>3 This study investigated the effect of a fluoride varnish (Duraphat Woelm Pharma GMBH & Co, Eschwege, Germany) on the retentive strength of temporary cementation.
MATERIAL
AND METHODS
A shoulder preparation for a complete crown was performed on an intact extracted human molar tooth. Preparation of the axial walls with a convergence angle of 10 degrees was accomplished with a hand piece clamped on a surveyor.4 A provisional crown of acrylic resin was made with a steel rod attached to the occlusal surface. The provisional crown was luted in four different ways for each cement: 1. Group 6, Cementation with a temporary luting agent 2. Group R + D, Recementation by applying Duraphat varnish to the inner surfaces (intaglio) of the dislodged crown from group C without removing the previous cement layer
aLecturer, Head of Laboratory for Biomaterials, Department of Restorative Dentistry. bInstructor, Department of Restorative Dentistry. cProfessor and Head, Department of Oral Surgery. dProfessor, Unit for Dental Research. 10/l/40876
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig.
1. Specimen in Instron testing machine.
3. Group M, Cementation with the luting agent mixed with Duraphat varnish 4. Group D + C, Duraphat varnish applied to the surface of the prepared tooth and cement placed in the provisional crown before cementation Two additional groups were also tested: 5. Group DU, Crown cemented with Duraphat varnish only 6. Group NC, No cement used Cementation was performed 30 seconds after the start of mixing at an ambient temperature of 23 t 1“ C, and a load of 50 N was exerted for the first minute. Before each cementation remnants of previous luting agents were removed, and the inner surface (intaglio) of the crown was cleaned with an applicator immersed in ethyl alcohol, except in group R + D. After cementation the samples were placed in storage with 100% relative humidity at 37” C. One hour later the retentive strength was measured with an Instron testing machine (Instron Corp., Canton, Mass.), using a cross-head speed of 5 mm/min (Fig. 1). Two ZOE base cements, one cement without eugenol, and the Du-
733
LEWINSTEIN
I. Temporary
Table
cements tested Type of material
Symbol
Product Tempbond
ET AL
cement
Free-Genol Temporary Opotow cement Duraphat varnish
pack
Batch No.
Manufacturer
TB
ZOE
Kerr Manufacturing
FG OP DU
No eugenol ZOE Varnish
GC, Itabashi-Ku, Japan Teledyne Getz, Elk Grove Village, Il. Woelm Pharma GMBH & Co., Eschwege, Germany
A-8-2236 B-8-2222 111181 58219 1721
Co., Romulus Mich.
ZOE, ‘&oxide-eugenol.
II. Retentive
Table
strength (Newtons)
Cement C
Recement R+D
Mixed M
D on tooth D
125 (8)
139 (14)
162 (24)
161 (16)
Conditions Tempbond
cement
and sample size (n) for each test
n
Opotow cements n Freegenol cement n Duraphat varnish n No cement n
10 [20%]
10 [90%]
10 [30%]
15 8 50 8 5 6 3 6
27 (8)
14 (5) 8 [IO%] 82 (11)
(4) [O%] (8) [20%] (1)
8 [lo%] 94 (15) 8 [SO%]
10 [30%]
III.
Two-factor
ANOVA
for determining
Factor cement (A) (B)
Temporary Conditions AB Error
Table
IV.
Significant
734
retentive
test.
strength
df
Sum of squares
Mean squares
F test
p Value
2 3 6 91
294064.875 10217.58 11257.98 12942.539
147032.438 3405.86 2876.33 142.226
1033.797 23.947 20.224
0.0001 0.0001
differences for retentive
0.0001
strength
TBI
TB2
TB3
TB4
FGl
FG2
TB2 TB3 TB4 FGl FG2 FG3 FG4
0.011 S S S S S S
NS S S S S S
NS s S S S
S S S S
S S S
S S
S
OPl
S
S
S
S
S
S
S
S
QP2 BP3 OP4
S S s
S S S
S S S
S S S
S S S
S S S
S S S
S S S
S, Significance at p < 0.01; NS, not significant group 2 (R + D).
(5) [Or,] (4) [SO%]
(0.3)
Numbers in parentheses represent standwd deviations. Numbers in brackets represent the percentage area of the tooth surface covered with cement after the retention
Table
8 [SO%]
15 8 36 8
FG3
FG4
OPl
OP2
OP3
0.014 NS NS
0.013 0.035
NS
p > 0.05. Numbers attached to symbols define the group number, for example, TB2 is equivalent
NOVEMBER
1992
VOLUME
68
to Tempbond
NUMBER
5
EFFECT
OF FLUORIDE
VARNISH
1 HOUR RETENTIVE
STRENGTH
f - 200 E 0z 160 2 iia
120
T-B
FG
TYPE
OP
D-U
NO CEM
OF CEMENT
Fig. 2. Means of determining retentive strength of temporary cements. Each cement was tested in four different groups: C, R i- D, M, and D + C.
raphat varnish were tested. The tested products are listed in Table I. The base/catalyst/Duraphat or B/C/D ratios for the cements used in group M were 6:2:1, 8:4:1, and 6:3:1, by weight for the TB, FG, and OP cements, respectively. The results were computed by means of two-factor analysis of variance with post hoc t tests, and all hypothesis testing was performed at the 95% level of confidence.
RESULTS
Fig. 3. Cemented crown and prepared tooth cement after retention tests. A, cementation with Tempbond cement. Cement covers inner surface of crown, whereas only remnants are on tooth surface. B, After recementation most of cement layer is attached to prepared tooth.
The mean retentive strengths of temporary cements with and without varnish are summarized in Table II and Fig. 2. Results of two-factor analysis of variance (ANOVA) (Table III) showed an interaction between the type of temporary cement and the method or condition of cementation. Comparison of means is shown in Table IV. Fig. 3, A and B are superior views of the prepared tooth, and the inner surface of the provisional crown after retentive tests, respectively, when Tempbond cement was used before and after recementation with Duraphat varnish. Fig. 4, A and B are lateral views of the prepared tooth surface after cementation with Freegenol cement and after recementation with Duraphat varnish.
DISCUSSION According to the results, l-hour retentive strengths were Tempbond > Freegenol > Opotowcement. Recementation with Duraphat varnish (group R + D) increased the retentive strength by approximately 11% , 88%, and 80 % for Tempbond, Freegenol, and Opotow cements, respectively. This additional strength enables the dentist to use Duraphat varnish for recementation without removing the previous layer of cement covering the inner surface of the temporary crown. Figs. 3 and 4 also confirmed the “transfer effect” of Duraphat varnish in recementation, because the Duraphat varnish transferred the previous cement layer from the provisional crown to the dentinal surface of THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 4. Prepared tooth after retention tests. A, Cementation with Freegenol cement. B, Recementation with Duraphat varnish. Entire surface of preparation is covered by cement. 735
LEWINSTEIN
the prepared tooth. For recementation, Duraphat varnish can serve as a reliable source of fluoride release to prevent5 caries and control microleakage between the cement and the prepared tooth surface. Olin et a1.6investigated the retentive strength of temporary cements with and without eugenol and reported retentive strengths of 15.3 kg for Freegenol and 8.8 kg for Tempbond cements. This research revealed values of 5.0 kg for Freegenol and 12.5 kg for Tempbond cements. The disparity between the values of these studies can be attributed to different intervals of testing. Olin et a1.6 reported 24-hour retentive strengths, whereas this study tested the strength 1 hour after mixing. Except for the Opotow cement, the mixture of Duraphat varnish and cement (group M) improved the l-hour retention. Applying Duraphat varnish to the tooth surface and cement to the inner surface of the crown (group D + C) enhanced the retentive strength of Tempbond, weakened the retention of Freegenol, but had no effect on Opotow cement. Despite the reduced retention of Freegenol cement on a Duraphat-coated tooth (group D + C), a layer of cement (80 % ) remained on the tooth, confirming an adhesive failure between the interim crown and the temporary cement. Concerning the remaining layer of cement, with the exception of the Opotow cement, Duraphat varnish enhanced the adherence of cement to the tooth structure rather than to the provisional crown (Table II). In a longitudinal study exceeding 8 years, Baini recorded limited secondary caries beneath permanent artificial crowns and fixed partial dentures when they were cemented with an interim cement. He concluded that “use of
ET AL
temporary cements in fixed prosthodontics facilitates correction of maintenance and their use should be given serious consideration.” SUMMARY
AND
CONCLUSION
A fluoride varnish, Duraphat, was combined with temporary cements to determine the effects on retention of provisional crowns. Results of this study indicate that temporary cement combined with Duraphat varnish may improve the clinical conditions during prolonged insertion of treatment restorations. REFERENCES 1. Bain CA. Retrospective evaluation of long-term temporary cementation iu fixed prosthodontics [Abstract]. J Dent Res 1990;69:No536. 2. Soremark R, Hedin M, Roejmyr R. Studies on incorporation of fluoride in cavity liier (varnish). Odontol Revy 1969;20:189-200. 3. Wolf 0, Gedalia I, Reisstein J, Goldman J, Stiegliz H. Effect of addition of CaF POs: a zinc oxide-eugenol base liner on the microhardness and fluoride content of dentin. J Dent Res 1973;52:467-71. 4. Grajower R, Lewinsteiu I. The effective minimum cement thickness of zinc phosphate cement for luted non-precious crowns. J Oral Rehabil 1985;12:235-45. 5. Alexander WE, McDonald RE, Stookey GK. Effectiveness of a stable 30% stannous fluoride solution in the prevention of recurrent dental caries. J Indian Dent Assoc 1969;48:174-80. 6. Olin PS, Rudney JD, Hill ME. Retentive strength of six temporary dental cements. Quint Int 1990;21:197-200. Reprint requests to: DR. ISRAEL LEWINSTEIN HEBREW UNIVERSITY-HADASSAH SCHOOL OF DENTAL MEDICINE P.O. Box 1172 JERUSALEM 91010, ISRAEL
NOVEMBER
1992
VOLUME
68
NUMBER
5
and
The retention of temporary crowns was studied with the use of a fluoride varnish (Duraphat) combined with various temporary cements. The mixture of Duraphat varnish and cement improved retention, with the exception of Opotow cement. Applying Duraphat varnish to the tooth surface before cementation enhanced the retentive strength of Tempbond, weakened the retention of Freegenol, but had no effect on Opotow cement. A “transfer effect” was observed, inasmuch as the Duraphat varnish encouraged adherence of the cement to the tooth structure rather than to the temporary crown. (J PROSTHETDENT 1992;68:‘733-6.)
emporary cements are important in restorative dentistry because they are luting agents for treatment restorations and for final castings.l Provisional restorations occasionally function for extended periods while adjunctive treatments such as periodontics, endodontics, orthodontics, or oral surgery are being completed. Interim restorations are susceptible to secondary caries when placed for a prolonged interval. A similar phenomenon can be observed with temporarily cemented final restorations, if the interim cement dissolves. The addition of fluoride compounds to zinc oxide-eugenol (ZOE) base has been shown to increase the microhardness of the dentin without compromising the physical properties of the liners.2>3 This study investigated the effect of a fluoride varnish (Duraphat Woelm Pharma GMBH & Co, Eschwege, Germany) on the retentive strength of temporary cementation.
MATERIAL
AND METHODS
A shoulder preparation for a complete crown was performed on an intact extracted human molar tooth. Preparation of the axial walls with a convergence angle of 10 degrees was accomplished with a hand piece clamped on a surveyor.4 A provisional crown of acrylic resin was made with a steel rod attached to the occlusal surface. The provisional crown was luted in four different ways for each cement: 1. Group 6, Cementation with a temporary luting agent 2. Group R + D, Recementation by applying Duraphat varnish to the inner surfaces (intaglio) of the dislodged crown from group C without removing the previous cement layer
aLecturer, Head of Laboratory for Biomaterials, Department of Restorative Dentistry. bInstructor, Department of Restorative Dentistry. cProfessor and Head, Department of Oral Surgery. dProfessor, Unit for Dental Research. 10/l/40876
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig.
1. Specimen in Instron testing machine.
3. Group M, Cementation with the luting agent mixed with Duraphat varnish 4. Group D + C, Duraphat varnish applied to the surface of the prepared tooth and cement placed in the provisional crown before cementation Two additional groups were also tested: 5. Group DU, Crown cemented with Duraphat varnish only 6. Group NC, No cement used Cementation was performed 30 seconds after the start of mixing at an ambient temperature of 23 t 1“ C, and a load of 50 N was exerted for the first minute. Before each cementation remnants of previous luting agents were removed, and the inner surface (intaglio) of the crown was cleaned with an applicator immersed in ethyl alcohol, except in group R + D. After cementation the samples were placed in storage with 100% relative humidity at 37” C. One hour later the retentive strength was measured with an Instron testing machine (Instron Corp., Canton, Mass.), using a cross-head speed of 5 mm/min (Fig. 1). Two ZOE base cements, one cement without eugenol, and the Du-
733
LEWINSTEIN
I. Temporary
Table
cements tested Type of material
Symbol
Product Tempbond
ET AL
cement
Free-Genol Temporary Opotow cement Duraphat varnish
pack
Batch No.
Manufacturer
TB
ZOE
Kerr Manufacturing
FG OP DU
No eugenol ZOE Varnish
GC, Itabashi-Ku, Japan Teledyne Getz, Elk Grove Village, Il. Woelm Pharma GMBH & Co., Eschwege, Germany
A-8-2236 B-8-2222 111181 58219 1721
Co., Romulus Mich.
ZOE, ‘&oxide-eugenol.
II. Retentive
Table
strength (Newtons)
Cement C
Recement R+D
Mixed M
D on tooth D
125 (8)
139 (14)
162 (24)
161 (16)
Conditions Tempbond
cement
and sample size (n) for each test
n
Opotow cements n Freegenol cement n Duraphat varnish n No cement n
10 [20%]
10 [90%]
10 [30%]
15 8 50 8 5 6 3 6
27 (8)
14 (5) 8 [IO%] 82 (11)
(4) [O%] (8) [20%] (1)
8 [lo%] 94 (15) 8 [SO%]
10 [30%]
III.
Two-factor
ANOVA
for determining
Factor cement (A) (B)
Temporary Conditions AB Error
Table
IV.
Significant
734
retentive
test.
strength
df
Sum of squares
Mean squares
F test
p Value
2 3 6 91
294064.875 10217.58 11257.98 12942.539
147032.438 3405.86 2876.33 142.226
1033.797 23.947 20.224
0.0001 0.0001
differences for retentive
0.0001
strength
TBI
TB2
TB3
TB4
FGl
FG2
TB2 TB3 TB4 FGl FG2 FG3 FG4
0.011 S S S S S S
NS S S S S S
NS s S S S
S S S S
S S S
S S
S
OPl
S
S
S
S
S
S
S
S
QP2 BP3 OP4
S S s
S S S
S S S
S S S
S S S
S S S
S S S
S S S
S, Significance at p < 0.01; NS, not significant group 2 (R + D).
(5) [Or,] (4) [SO%]
(0.3)
Numbers in parentheses represent standwd deviations. Numbers in brackets represent the percentage area of the tooth surface covered with cement after the retention
Table
8 [SO%]
15 8 36 8
FG3
FG4
OPl
OP2
OP3
0.014 NS NS
0.013 0.035
NS
p > 0.05. Numbers attached to symbols define the group number, for example, TB2 is equivalent
NOVEMBER
1992
VOLUME
68
to Tempbond
NUMBER
5
EFFECT
OF FLUORIDE
VARNISH
1 HOUR RETENTIVE
STRENGTH
f - 200 E 0z 160 2 iia
120
T-B
FG
TYPE
OP
D-U
NO CEM
OF CEMENT
Fig. 2. Means of determining retentive strength of temporary cements. Each cement was tested in four different groups: C, R i- D, M, and D + C.
raphat varnish were tested. The tested products are listed in Table I. The base/catalyst/Duraphat or B/C/D ratios for the cements used in group M were 6:2:1, 8:4:1, and 6:3:1, by weight for the TB, FG, and OP cements, respectively. The results were computed by means of two-factor analysis of variance with post hoc t tests, and all hypothesis testing was performed at the 95% level of confidence.
RESULTS
Fig. 3. Cemented crown and prepared tooth cement after retention tests. A, cementation with Tempbond cement. Cement covers inner surface of crown, whereas only remnants are on tooth surface. B, After recementation most of cement layer is attached to prepared tooth.
The mean retentive strengths of temporary cements with and without varnish are summarized in Table II and Fig. 2. Results of two-factor analysis of variance (ANOVA) (Table III) showed an interaction between the type of temporary cement and the method or condition of cementation. Comparison of means is shown in Table IV. Fig. 3, A and B are superior views of the prepared tooth, and the inner surface of the provisional crown after retentive tests, respectively, when Tempbond cement was used before and after recementation with Duraphat varnish. Fig. 4, A and B are lateral views of the prepared tooth surface after cementation with Freegenol cement and after recementation with Duraphat varnish.
DISCUSSION According to the results, l-hour retentive strengths were Tempbond > Freegenol > Opotowcement. Recementation with Duraphat varnish (group R + D) increased the retentive strength by approximately 11% , 88%, and 80 % for Tempbond, Freegenol, and Opotow cements, respectively. This additional strength enables the dentist to use Duraphat varnish for recementation without removing the previous layer of cement covering the inner surface of the temporary crown. Figs. 3 and 4 also confirmed the “transfer effect” of Duraphat varnish in recementation, because the Duraphat varnish transferred the previous cement layer from the provisional crown to the dentinal surface of THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 4. Prepared tooth after retention tests. A, Cementation with Freegenol cement. B, Recementation with Duraphat varnish. Entire surface of preparation is covered by cement. 735
LEWINSTEIN
the prepared tooth. For recementation, Duraphat varnish can serve as a reliable source of fluoride release to prevent5 caries and control microleakage between the cement and the prepared tooth surface. Olin et a1.6investigated the retentive strength of temporary cements with and without eugenol and reported retentive strengths of 15.3 kg for Freegenol and 8.8 kg for Tempbond cements. This research revealed values of 5.0 kg for Freegenol and 12.5 kg for Tempbond cements. The disparity between the values of these studies can be attributed to different intervals of testing. Olin et a1.6 reported 24-hour retentive strengths, whereas this study tested the strength 1 hour after mixing. Except for the Opotow cement, the mixture of Duraphat varnish and cement (group M) improved the l-hour retention. Applying Duraphat varnish to the tooth surface and cement to the inner surface of the crown (group D + C) enhanced the retentive strength of Tempbond, weakened the retention of Freegenol, but had no effect on Opotow cement. Despite the reduced retention of Freegenol cement on a Duraphat-coated tooth (group D + C), a layer of cement (80 % ) remained on the tooth, confirming an adhesive failure between the interim crown and the temporary cement. Concerning the remaining layer of cement, with the exception of the Opotow cement, Duraphat varnish enhanced the adherence of cement to the tooth structure rather than to the provisional crown (Table II). In a longitudinal study exceeding 8 years, Baini recorded limited secondary caries beneath permanent artificial crowns and fixed partial dentures when they were cemented with an interim cement. He concluded that “use of
ET AL
temporary cements in fixed prosthodontics facilitates correction of maintenance and their use should be given serious consideration.” SUMMARY
AND
CONCLUSION
A fluoride varnish, Duraphat, was combined with temporary cements to determine the effects on retention of provisional crowns. Results of this study indicate that temporary cement combined with Duraphat varnish may improve the clinical conditions during prolonged insertion of treatment restorations. REFERENCES 1. Bain CA. Retrospective evaluation of long-term temporary cementation iu fixed prosthodontics [Abstract]. J Dent Res 1990;69:No536. 2. Soremark R, Hedin M, Roejmyr R. Studies on incorporation of fluoride in cavity liier (varnish). Odontol Revy 1969;20:189-200. 3. Wolf 0, Gedalia I, Reisstein J, Goldman J, Stiegliz H. Effect of addition of CaF POs: a zinc oxide-eugenol base liner on the microhardness and fluoride content of dentin. J Dent Res 1973;52:467-71. 4. Grajower R, Lewinsteiu I. The effective minimum cement thickness of zinc phosphate cement for luted non-precious crowns. J Oral Rehabil 1985;12:235-45. 5. Alexander WE, McDonald RE, Stookey GK. Effectiveness of a stable 30% stannous fluoride solution in the prevention of recurrent dental caries. J Indian Dent Assoc 1969;48:174-80. 6. Olin PS, Rudney JD, Hill ME. Retentive strength of six temporary dental cements. Quint Int 1990;21:197-200. Reprint requests to: DR. ISRAEL LEWINSTEIN HEBREW UNIVERSITY-HADASSAH SCHOOL OF DENTAL MEDICINE P.O. Box 1172 JERUSALEM 91010, ISRAEL
NOVEMBER
1992
VOLUME
68
NUMBER
5
