TEETHRESTOREDWITHFIXEDPROSTHESES
5. Grajower chamber
11. Andreasen JO. Traumatic injuries of the teeth. 2nd ed. Philadelphia: WB Saunders, 1981;49-69. 12. Weine FS. Endodontic therapy. 4th ed. St Louis: CV Mosby, 1989;24-
R, Shakarbani S, Kaufman E. Temperature rise in pulp during fabrication of temporary self-curing crowns. J PROS-
THET DENT
1979;41:535-40.
_”
6. Tobias RS. Pulpal response to a temporary crown and bridge material in ferret teeth. J Oral Rehabil 1980;7:387-93. 7. Brannstrom M, Nyborg H. Pulpal reaction to polycarboxylate and zinc phosphate cements used with inlays in deep cavity preparations. J Am Dent Assoc 1977;94:308. 8. Eames WB, Hendrix K, Mohler HC. Pulpal response in Rhesus monkeys to cementation agents and cleaners. J Am Dent Assoc 19’79;98:40-5. 9. Bergenholtz G, Cox CF, Loesche WJ, Syed SA. Bacterialleakage around dental restorations: its effect on the dental pulp. J Oral Path01 1982; 11:439-50. IO. Suzuki M, Goto G, Jordan RE. Pulpal response to pin placement. J Am Dent Assoc 1970;87:636-40.
Temperature liquids D. S. Palmer,
extremes BS, DMD,a
U.S. Air Force Hospital Calif., and Naval Dental
Chanute, School,
Reprint requests to: DR. C. RUSSELL JACKSON RM 1088 HSN WEST VIRGINIA UNIVERSITY MORGANTOWN. WV 26506
produced
M. T. Barco, Chanute National
I.%
13. Pashley DH, Kepler EE, Williams EC, Okabe A. A progressive decrease in dentine permeability following cavity preparation. Arch Oral Biol 1983;28:853-8.
AFB, Naval
DDS,
MSD,b
Ill., U.S. Navy Dental Center,
orally
SCHOOL
OF DENTISTRY
by hot and cold
and E. J. Billy,
DMD@
Dental Clinic, Camp Bethesda, Md.
Pendleton,
Thermocycling in vitro is a common way of testing dental materials to aid in establishing suitability for in vivo use. There is no standard temperature range for dental material thermocycling. This research attempts to establish an appropriate temperature range by measuring extremes of temperature achieved orally in human volunteer subjects. By using an intraoral digital thermometer probe, 13 human subjects were observed as they drank very hot and cold liquids. The temperature extremes produced intraorally were measured and adjusted for possible error. The results of this study suggest that a range of 0” to 67O C may be appropriate for dental material thermocycling. (J PROSTHET DENT 1992;67:325-7.)
E.
xposmg dental materials to a range of temperatures is a commonpart of dental material testing. It is important that the temperature rangeusedfor thermocycling be appropriate. The temperature rangeusedshould reflect temperatures that might exist intraorally. Too extreme a range could overstressthe material and possibly indicate that the material is unsatisfactory when this is not so.This assumptioncould deny the dental community the use of material that is in fact satisfactory. In contrast, too limited a temperature range may not adequately stressthe material and possiblyallow clinically deficient materialsinto the dental community. Temperature ranges for testing have often been selectedarbitrarily. The opinions or assertions contained in this article are those of the authors and are not to be construed as official or aa reflecting the views of the Department of the Air Force, the Department of the Navy, or the Department of Defense. aLieutenant Colonel, U.S. Air Force (DC), Chanute AFB. bCaptain, U.S. Navy (DC), Camp Pendleton, Calif. CCaptain, U.S. Navy (DC), Prosthodontics Department, National Naval Dental Center, Bethesda, Md.
10/l/32696
THEJOURNAL
OF PROSTHETIC
DENTISTRY
Nelsenet al.’ measuredtemperature extremesat the inner tooth surface below a resin restoration and reported a rangeof 9” to 52’ C asbeing the extremesreachableorally. They did not measuretemperature variation at the outer surfaceof the tooth. It would appear logical that the outer surfaceof the tooth isthe region wheretemperature change would be mostdramatic and alsowhererestoration leakage would start. The outer surface of the tooth is then where temperature extremes should be measured. There are no published data on the maximum or minimum temperatures that can actually be reached at the tooth surface in vivo. Researchersnow use a variety of temperature rangesfor thermocycling, frequently selecting the freezing point of water as a lower limit2 and temperatures about halfway from the freezing point to the boiling point of water asthe upper limit.2-3 Typical temperature rangesin current literature are (in degreescentigrade): 5’ to 60”,4 loo to 50°,54Oto 58°,65” to 55’,’ 4’ to 6O”,s2’ to 50’ ’ and 7’ to 5OO.l’ 1; would seemreasonablethat ingesting hot or cold substancesis the causeof the most extreme temperature variations orally. The purpose of this in vivo study wasto de-
325
PALMER,
Fig.
1. Digital
thermometer
AND
at mandibular
Fig.
3. Thermocouple
at maxillary
BILLY
molar site.
incisor site.
METHODS
Thirteen subjects, 10 men aged 32 to 62 years and three women aged 35 to 42 years, all staff members or residents of the Naval Dental School, Bethesda, Maryland, were selected at random. The informed consent of all human subjects who participated in this study was obtained after the nature of the procedure and possible discomforts and risks had been fully explained. The only selection criterion was that there be a least one intact lower dental quadrant (at least one premolar and an adjacent molar). Temperature was recorded using a digital thermometer (Model 51, John Fluke Manufacturing Co., Everett, Wash.) (Fig. 1). This meter reads out to the nearest 0.1’ C. For the initial readings, the wire lead to the sensor was positioned along the central fossae of the mandibular teeth. The sensor itself was placed at the mesial aspect of the occlusal surface of the mandibular first molar (Fig. 2). Either side of the dental arch was used without preference or distinction. The sensor and its lead were attached to the teeth by dental floss passed through the embrasures of the premolar or canine teeth and tied over the wire lead. Temperature information was read from the digital thermometer and was recorded. Most subjects were tested for both an extreme high and an extreme low temperature. Extreme high temperatures 326
2. Thermocouple
AND
and thermocouple.
termine the highest and lowest temperature that can reasonably be achieved at the tooth surface by ingesting very hot and cold substances.
MATERIALS
Fig.
BARCO,
were determined by heating tap water in a microwave oven to a temperature just below boiling (typically about 90° C). The subjects were then asked to test the water by moving it close to the mouth and, if they felt comfortable doing so, to sip the water. Each subject was cautioned not to sip water that might be hot enough to cause pain or injury. If the water was too hot to sip, it was allowed to cool until the subject was able to sip it without being injured by the heat. The temperature at which this occurred was noted. In each instance it was above 61’ C. Once the starting temperature was comfortable for the subject, it was noted and the subject sipped the water for 1 minute with the probe readings being recorded. This procedure was repeated for five l-minute trials, recording the starting probe temperature and each temperature that was higher than those previously noted on that particular trial. Only the one highest temperature recorded for each subject was used for analysis. High temperature data were also recorded with the probe located on the palatal surface of the maxillary central incisors (Fig. 3). Using the mandibular molar location, the lower temperature was determined in a similar manner. MARCH
1992
VOLUME
67
NUMBER
3
ORAL
TEMPERATURE
EXTREMES
Subjects were asked to hold an ice cube in the mouth by closing the teeth together on the cube while it rested in contact with the probe. Five 2-minute trials were used for each subject. The probe was located on the occlusal surface of the mandibular first molar because this location facilitated holding the ice in contact with the probe. The starting temperature and each lower reading was recorded for each trial.
RESULTS Temperature extremes for each probe location are shown in Table I. The mandibular posterior site yielded an average high temperature of 53.1’ C, with a standard deviation of + 4.1’ C. That same site showed an average low temperature of 1.0’ C, with a standard deviation of f 1.0’ C. The maxillary anterior site showed the highest of the high temperatures, with an average of 58.5’ C, with a standard deviation of 13.3” C.
DISCUSSION
JOURNAL
OF
PROSTHETIC
DENTISTRY
extremes High
Patient
temp.
Sex
1 2 3 4 5 6 7 8 9
M M M M
10
M
11
F
12 13
M M
M
52.6
56.7
58.1
61.8
54.1
59.9
53.2 42.0 54.8 54.3
54.4
M
51.7
F
54.6 57.3 50.7 53.2
F
Not
man&
temp. max.
obs
mandibular;
lated lower temperature source (0.8” C - 2 x 1.0” temperature of 0.0” C is standard deviations (2 X up to 66.9” C, or simply
Low temp. Posterior mand. -0.1 0.0 1.0 -0.1
Not obs
1.4
59.5 59.2 55.2 62.0 62.6
0.2 1.6 0.5 2.9 0.8 2.1
Not obs Not obs
53.1 + 4.1
Temperature;
High
mand.
M
Mean + SD
(in degrees centigrade)
Anterior
Posterior
No.
Temp.,
When foods or liquids of extreme temperature are ingested, oral tissues and saliva tend to return those foods and oral structures to normal oral temperature. Temperatures achievable orally may not be identical to food or drink temperatures. Ice was chosen as a low temperature source because of its common use by people and its ability to produce a lasting cooling effect. Some people do hold ice cubes in their mouths or chew ice. For the high limit, hot water was chosen to simulate the effect of hot liquids such as coffee, tea, or soup. Initially the mandibular molar location was used for the high-temperature measurements. However, the maxillary anterior location was tried later; the highest readings were seen at the palatal surface of the maxillary incisors. Data from both locations are reported, but the recommended high temperature for thermocycling is derived from the maxillary anterior readings. As the intent of this study was to observe and report temperature extremes, all corrections for the high end temperature data were made so as to increase the high temperature point. Likewise, all corrections to the low end temperature were made so as to lower it, but going no lower than the temperature of the cold source used for intraoral testing. The manufacturer of the thermometer guarantees accuracy of f 1.8’ C.” In testing the thermometer with an insulated ice bath, an accuracy of + 0.2’ C was observed. There was no calibration source available for the 60 to 70” C high end temperature range. Therefore the manufacturer’s full error tolerance must be assumed for the high end temperatures. This means that the average low end temperature was corrected for a possible error of 0.2’ C, bringing it down to 0.8” C. Also, the high end average temperature was corrected by 1.8’ C, raising it 60.3’ C. After adjusting for error tolerance, two standard deviations were allowed to best guarantee adequate range. Two standard deviations (2 x 1.0’ C) would make the calcuTHE
Table I. Temperature at each probe location
53.8 58.5 f 3.3 mar,
maxillary;
1.8
Not obs 1.0
+ 1.0
obs, observed.
slightly below the actual cold C = -1.2’ C); the actual source therefore suggested. Adding two 3.3” C) brings the 60.3’ C point 67’ C.
CONCLUSION The results of this study suggest that a range of 0” to 67” C may be appropriate for thermocycling dental materials. REFERENCES 1. Nelsen RJ, Wolcott RB, PafTenbarger GC. Fluid exchange at the margins of dental restorations. J Am Dent Assoc 1952;44:289-95. 2. Mesu FP. The effect of temperature on the compressive and tensile strengths of cements. J PROSTHET DENT 1983;49:59-62. 3. Crim GA, Swartz ML, Phillips RW. Comparison of four thermocycling techniques. J PROSTHET DENT 1985,53:50-3. 4. Perkins E, McInnes-Ledoux PM, Weinberg R. In vitro microleakage of glass ionomer/composite laminate class V restorations [Abstract]. J Dent Res 1988,67:309. 5. Kanca J III. Effect of reduced etching times on microleakage of composite resins [Abstract]. J Dent Res 1988;67:309. 6. Reeves GW, Fitchie JG, Hembree JH, Swift EJ, Quiroz L. In vitro microleakage of ten dentin bonding systems [Abstract]. J Dent Res 1988;67:310. ‘7. Sridawasdi S, Boyer DB, Reinhardt JW. The effect of the dentinal smear layer on microleakage of restorations [Abstract]. J Dent Res 1988,67:310. 8. Kajeimoto Y, Kohara 0, Yao K, Hieda T. New microleakage test method utilizing resorcinol formaldehyde resin [Abstract]. J Dent Res 1988; 67:310. 9. Andresen GF, Bishara SE, Stieg MA, Jakobsen JR. Bonding and debonding to smooth porcelain and enamel [Abstract]. J Dent Res 1988,67:312. 10. Smith LA, O’Brien JA, Retief DH, Bradley EL. Microleakage of two dentinalbondingrestorativesystems [Abstract]. JDentRes 1988;67:309. 11. Operator’s Manual. Model 51 K/J Thermometer. Everett, Washington: John Fluke Manufacturing Co, 1985.
Reprint
requests
to:
DAVID S. PALMER, LT COL, USAF, USAF HOSPITAL CHANUTE/SGD CHANUTE AFB, IL 61868
DC
327
5. Grajower chamber
11. Andreasen JO. Traumatic injuries of the teeth. 2nd ed. Philadelphia: WB Saunders, 1981;49-69. 12. Weine FS. Endodontic therapy. 4th ed. St Louis: CV Mosby, 1989;24-
R, Shakarbani S, Kaufman E. Temperature rise in pulp during fabrication of temporary self-curing crowns. J PROS-
THET DENT
1979;41:535-40.
_”
6. Tobias RS. Pulpal response to a temporary crown and bridge material in ferret teeth. J Oral Rehabil 1980;7:387-93. 7. Brannstrom M, Nyborg H. Pulpal reaction to polycarboxylate and zinc phosphate cements used with inlays in deep cavity preparations. J Am Dent Assoc 1977;94:308. 8. Eames WB, Hendrix K, Mohler HC. Pulpal response in Rhesus monkeys to cementation agents and cleaners. J Am Dent Assoc 19’79;98:40-5. 9. Bergenholtz G, Cox CF, Loesche WJ, Syed SA. Bacterialleakage around dental restorations: its effect on the dental pulp. J Oral Path01 1982; 11:439-50. IO. Suzuki M, Goto G, Jordan RE. Pulpal response to pin placement. J Am Dent Assoc 1970;87:636-40.
Temperature liquids D. S. Palmer,
extremes BS, DMD,a
U.S. Air Force Hospital Calif., and Naval Dental
Chanute, School,
Reprint requests to: DR. C. RUSSELL JACKSON RM 1088 HSN WEST VIRGINIA UNIVERSITY MORGANTOWN. WV 26506
produced
M. T. Barco, Chanute National
I.%
13. Pashley DH, Kepler EE, Williams EC, Okabe A. A progressive decrease in dentine permeability following cavity preparation. Arch Oral Biol 1983;28:853-8.
AFB, Naval
DDS,
MSD,b
Ill., U.S. Navy Dental Center,
orally
SCHOOL
OF DENTISTRY
by hot and cold
and E. J. Billy,
DMD@
Dental Clinic, Camp Bethesda, Md.
Pendleton,
Thermocycling in vitro is a common way of testing dental materials to aid in establishing suitability for in vivo use. There is no standard temperature range for dental material thermocycling. This research attempts to establish an appropriate temperature range by measuring extremes of temperature achieved orally in human volunteer subjects. By using an intraoral digital thermometer probe, 13 human subjects were observed as they drank very hot and cold liquids. The temperature extremes produced intraorally were measured and adjusted for possible error. The results of this study suggest that a range of 0” to 67O C may be appropriate for dental material thermocycling. (J PROSTHET DENT 1992;67:325-7.)
E.
xposmg dental materials to a range of temperatures is a commonpart of dental material testing. It is important that the temperature rangeusedfor thermocycling be appropriate. The temperature rangeusedshould reflect temperatures that might exist intraorally. Too extreme a range could overstressthe material and possibly indicate that the material is unsatisfactory when this is not so.This assumptioncould deny the dental community the use of material that is in fact satisfactory. In contrast, too limited a temperature range may not adequately stressthe material and possiblyallow clinically deficient materialsinto the dental community. Temperature ranges for testing have often been selectedarbitrarily. The opinions or assertions contained in this article are those of the authors and are not to be construed as official or aa reflecting the views of the Department of the Air Force, the Department of the Navy, or the Department of Defense. aLieutenant Colonel, U.S. Air Force (DC), Chanute AFB. bCaptain, U.S. Navy (DC), Camp Pendleton, Calif. CCaptain, U.S. Navy (DC), Prosthodontics Department, National Naval Dental Center, Bethesda, Md.
10/l/32696
THEJOURNAL
OF PROSTHETIC
DENTISTRY
Nelsenet al.’ measuredtemperature extremesat the inner tooth surface below a resin restoration and reported a rangeof 9” to 52’ C asbeing the extremesreachableorally. They did not measuretemperature variation at the outer surfaceof the tooth. It would appear logical that the outer surfaceof the tooth isthe region wheretemperature change would be mostdramatic and alsowhererestoration leakage would start. The outer surface of the tooth is then where temperature extremes should be measured. There are no published data on the maximum or minimum temperatures that can actually be reached at the tooth surface in vivo. Researchersnow use a variety of temperature rangesfor thermocycling, frequently selecting the freezing point of water as a lower limit2 and temperatures about halfway from the freezing point to the boiling point of water asthe upper limit.2-3 Typical temperature rangesin current literature are (in degreescentigrade): 5’ to 60”,4 loo to 50°,54Oto 58°,65” to 55’,’ 4’ to 6O”,s2’ to 50’ ’ and 7’ to 5OO.l’ 1; would seemreasonablethat ingesting hot or cold substancesis the causeof the most extreme temperature variations orally. The purpose of this in vivo study wasto de-
325
PALMER,
Fig.
1. Digital
thermometer
AND
at mandibular
Fig.
3. Thermocouple
at maxillary
BILLY
molar site.
incisor site.
METHODS
Thirteen subjects, 10 men aged 32 to 62 years and three women aged 35 to 42 years, all staff members or residents of the Naval Dental School, Bethesda, Maryland, were selected at random. The informed consent of all human subjects who participated in this study was obtained after the nature of the procedure and possible discomforts and risks had been fully explained. The only selection criterion was that there be a least one intact lower dental quadrant (at least one premolar and an adjacent molar). Temperature was recorded using a digital thermometer (Model 51, John Fluke Manufacturing Co., Everett, Wash.) (Fig. 1). This meter reads out to the nearest 0.1’ C. For the initial readings, the wire lead to the sensor was positioned along the central fossae of the mandibular teeth. The sensor itself was placed at the mesial aspect of the occlusal surface of the mandibular first molar (Fig. 2). Either side of the dental arch was used without preference or distinction. The sensor and its lead were attached to the teeth by dental floss passed through the embrasures of the premolar or canine teeth and tied over the wire lead. Temperature information was read from the digital thermometer and was recorded. Most subjects were tested for both an extreme high and an extreme low temperature. Extreme high temperatures 326
2. Thermocouple
AND
and thermocouple.
termine the highest and lowest temperature that can reasonably be achieved at the tooth surface by ingesting very hot and cold substances.
MATERIALS
Fig.
BARCO,
were determined by heating tap water in a microwave oven to a temperature just below boiling (typically about 90° C). The subjects were then asked to test the water by moving it close to the mouth and, if they felt comfortable doing so, to sip the water. Each subject was cautioned not to sip water that might be hot enough to cause pain or injury. If the water was too hot to sip, it was allowed to cool until the subject was able to sip it without being injured by the heat. The temperature at which this occurred was noted. In each instance it was above 61’ C. Once the starting temperature was comfortable for the subject, it was noted and the subject sipped the water for 1 minute with the probe readings being recorded. This procedure was repeated for five l-minute trials, recording the starting probe temperature and each temperature that was higher than those previously noted on that particular trial. Only the one highest temperature recorded for each subject was used for analysis. High temperature data were also recorded with the probe located on the palatal surface of the maxillary central incisors (Fig. 3). Using the mandibular molar location, the lower temperature was determined in a similar manner. MARCH
1992
VOLUME
67
NUMBER
3
ORAL
TEMPERATURE
EXTREMES
Subjects were asked to hold an ice cube in the mouth by closing the teeth together on the cube while it rested in contact with the probe. Five 2-minute trials were used for each subject. The probe was located on the occlusal surface of the mandibular first molar because this location facilitated holding the ice in contact with the probe. The starting temperature and each lower reading was recorded for each trial.
RESULTS Temperature extremes for each probe location are shown in Table I. The mandibular posterior site yielded an average high temperature of 53.1’ C, with a standard deviation of + 4.1’ C. That same site showed an average low temperature of 1.0’ C, with a standard deviation of f 1.0’ C. The maxillary anterior site showed the highest of the high temperatures, with an average of 58.5’ C, with a standard deviation of 13.3” C.
DISCUSSION
JOURNAL
OF
PROSTHETIC
DENTISTRY
extremes High
Patient
temp.
Sex
1 2 3 4 5 6 7 8 9
M M M M
10
M
11
F
12 13
M M
M
52.6
56.7
58.1
61.8
54.1
59.9
53.2 42.0 54.8 54.3
54.4
M
51.7
F
54.6 57.3 50.7 53.2
F
Not
man&
temp. max.
obs
mandibular;
lated lower temperature source (0.8” C - 2 x 1.0” temperature of 0.0” C is standard deviations (2 X up to 66.9” C, or simply
Low temp. Posterior mand. -0.1 0.0 1.0 -0.1
Not obs
1.4
59.5 59.2 55.2 62.0 62.6
0.2 1.6 0.5 2.9 0.8 2.1
Not obs Not obs
53.1 + 4.1
Temperature;
High
mand.
M
Mean + SD
(in degrees centigrade)
Anterior
Posterior
No.
Temp.,
When foods or liquids of extreme temperature are ingested, oral tissues and saliva tend to return those foods and oral structures to normal oral temperature. Temperatures achievable orally may not be identical to food or drink temperatures. Ice was chosen as a low temperature source because of its common use by people and its ability to produce a lasting cooling effect. Some people do hold ice cubes in their mouths or chew ice. For the high limit, hot water was chosen to simulate the effect of hot liquids such as coffee, tea, or soup. Initially the mandibular molar location was used for the high-temperature measurements. However, the maxillary anterior location was tried later; the highest readings were seen at the palatal surface of the maxillary incisors. Data from both locations are reported, but the recommended high temperature for thermocycling is derived from the maxillary anterior readings. As the intent of this study was to observe and report temperature extremes, all corrections for the high end temperature data were made so as to increase the high temperature point. Likewise, all corrections to the low end temperature were made so as to lower it, but going no lower than the temperature of the cold source used for intraoral testing. The manufacturer of the thermometer guarantees accuracy of f 1.8’ C.” In testing the thermometer with an insulated ice bath, an accuracy of + 0.2’ C was observed. There was no calibration source available for the 60 to 70” C high end temperature range. Therefore the manufacturer’s full error tolerance must be assumed for the high end temperatures. This means that the average low end temperature was corrected for a possible error of 0.2’ C, bringing it down to 0.8” C. Also, the high end average temperature was corrected by 1.8’ C, raising it 60.3’ C. After adjusting for error tolerance, two standard deviations were allowed to best guarantee adequate range. Two standard deviations (2 x 1.0’ C) would make the calcuTHE
Table I. Temperature at each probe location
53.8 58.5 f 3.3 mar,
maxillary;
1.8
Not obs 1.0
+ 1.0
obs, observed.
slightly below the actual cold C = -1.2’ C); the actual source therefore suggested. Adding two 3.3” C) brings the 60.3’ C point 67’ C.
CONCLUSION The results of this study suggest that a range of 0” to 67” C may be appropriate for thermocycling dental materials. REFERENCES 1. Nelsen RJ, Wolcott RB, PafTenbarger GC. Fluid exchange at the margins of dental restorations. J Am Dent Assoc 1952;44:289-95. 2. Mesu FP. The effect of temperature on the compressive and tensile strengths of cements. J PROSTHET DENT 1983;49:59-62. 3. Crim GA, Swartz ML, Phillips RW. Comparison of four thermocycling techniques. J PROSTHET DENT 1985,53:50-3. 4. Perkins E, McInnes-Ledoux PM, Weinberg R. In vitro microleakage of glass ionomer/composite laminate class V restorations [Abstract]. J Dent Res 1988,67:309. 5. Kanca J III. Effect of reduced etching times on microleakage of composite resins [Abstract]. J Dent Res 1988;67:309. 6. Reeves GW, Fitchie JG, Hembree JH, Swift EJ, Quiroz L. In vitro microleakage of ten dentin bonding systems [Abstract]. J Dent Res 1988;67:310. ‘7. Sridawasdi S, Boyer DB, Reinhardt JW. The effect of the dentinal smear layer on microleakage of restorations [Abstract]. J Dent Res 1988,67:310. 8. Kajeimoto Y, Kohara 0, Yao K, Hieda T. New microleakage test method utilizing resorcinol formaldehyde resin [Abstract]. J Dent Res 1988; 67:310. 9. Andresen GF, Bishara SE, Stieg MA, Jakobsen JR. Bonding and debonding to smooth porcelain and enamel [Abstract]. J Dent Res 1988,67:312. 10. Smith LA, O’Brien JA, Retief DH, Bradley EL. Microleakage of two dentinalbondingrestorativesystems [Abstract]. JDentRes 1988;67:309. 11. Operator’s Manual. Model 51 K/J Thermometer. Everett, Washington: John Fluke Manufacturing Co, 1985.
Reprint
requests
to:
DAVID S. PALMER, LT COL, USAF, USAF HOSPITAL CHANUTE/SGD CHANUTE AFB, IL 61868
DC
327
