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Bacteriologic evaluation of the glass bead sterilizer for endodontics
ENDODONTICS .
.
.
.
.
.
BACTERIOLOGIC FOR
.
.
.
.
EVALUATION
.
.
.
.
OF THE
.
.
.
GLASS
.
.
BEAD
.
.
.
.
.
STERILIZER
ENDODONTICS
Paul A-. Spring,
D.D.S.,”
Utica, N. Y.
suggested molten metal as a potential sterilizing agent for use in the dental office. Roak’ concluded that a five-second exposure of metal instruments contaminated with vegetative and sporulated organisms in molten metal was an effective means of sterilization ; swabs with vegetative organisms required five seconds, but a ten-second exposure was required to destroy spores on cotton swabs. He used Streptococcus viridans, Streptococcus hemolyticus, Staphylococcus sp., and Bacillus subtilis. No
F
LAHERTY3
*Resident
in Oral
Surgery,
Buffalo
Veterans 353
Administration
Hospital.
354
0 5.. 0. hl. a 0. I’.
SPEING
.\I.trrh.
I’li’i
for effective heat transfer, a tempcraturc range of 225 to 250° C., and a temptI-nturc differential of 30° c’. within the sterilizer. illthougll neither organisms nor time intervals were specified, Grossman suggested that the duration of heat exposure should be equivalent to the conventional timcbx used for molten metal sterilization. 11 temperature analysis of thermostatically controlled root, cana, sterilizers was rcportcd by Olict, Sorin, and Brown,” who drtermincd tha.t a. definite tcmperaturc gradient was exhibited between the base and snrfact and the outer circnmferencc and center of the ~11 of all sterilizers. Nanufacturcrs’ literature* suggested that with 1 mm. solid glass sphcrcs and a tcmperaturc of GO0 F’., a three- to five-second esposnrc -for metal broaches and a t,en-second exposure for paper or cotton material was rquirrtl for sterilization of eontaminatcd mat,CriiIlS. MATERIALS
AiXD
XETHOD?:
A commercial glass bead sterilizert was used in the following study. Sterilizer temperatures were measured with a mercury-filled thermometer. Temperature strata as a function of immersion dept.h were observed and arc recorded in Table I with emergent. stem corrections applied to the data.* TABLE
I.
TEMPERATIJRE
VARIATIOK
AS A FUKCTION
OF IMUERSION
DEPTH
Deuth--cm.
Because of the temperature strata, all broaches and paper points mere immersed to the bottom of the sterilizer, to ensure a more constant heat exposure of the test instruments. *Electra-ball iEmergent
sterilizer, stem correction
Union is
Broacn 11.5’
Co., C.
Inc.,
New
York,
New
York.
Volume Number
BACTERIAL
I2 3
EVALUATION
OF
GLASS
READ
STERILIZER
355
Efficiency of heat sterilization by the ball sterilizer was determined on an ‘Lall-or-none” basis. Dental broaches, paper points,” and associated equipment, were autoclavcd at 121.O C. for twenty minutes and contaminated by seizing the broaches or points with sterile forceps and immersing them in a They were removed after thirty twenty-four-hour culture of test organisms. seconds’ exposure and placed upon a sterile paper filter in a covered Petri Then the contaminated dental materials were dish lo remove cxccss moisture. removed with forceps from the P&i plates and held among the glass bends in the ball sterilizer for varying times; they were rcmovcd, dropped into rccovery broth, and incubated at 37O C., and the results were recorded after seventy-t,wo hours. The results of these experiments arc shown in Tables II and II r. Recovery broth used in these cxpcrimcnts was eith(ir t rypticasct soy or veal infusion.$ In all cases, cxpcrirncntally contaminated hroachcs and paper points grew well in both types of recovery broth. Test organisms used in this study were Streptococcus fecnlis (an cnterococcus), Stnph~ylococcus CITIHL.S, Escherichirr. coli, and Monilirl dlkrrns. RIBTiLTS
AND
DISCUSSION
The commercial ball stcrilizcr used in these experiments displayed approximately a 5Z” C. temperature variation (corrected for emergent stem) between the bottom of the unit and the surface of the glass balls, as charted in Table I. This variation was surprising but not unexpected, since the construction of the unit placed all heating coils in the bottom with a modified Dewar flask as the container. Irrespective of ambient temperatures, the highest tcmpcratures noted in this study were between 210 and 215’ C. at the floor of the unit,. Standardization of the technique result,ed in the introductiou of all test substances to the bottom of the unit, a 6 cm. immersion depth. At this position daily variations in trmpcratures ~vcro minimized to an incrrincnt of i4o c. Table 11 shows the time exposure required to sterilize contaminated metal I)~~a~hs. Wit.h E. coli as the test organism, broaches were sterile with ;I oncsecond exposure to 211° C. In a few instances, a t,wo- or three-second exposure wa.s required to effect sterilization, in accord with the two-second oxposurc designated bay &wart and Williams. Stwphylococcus dbus n-as usually destroyed by a two-second exposure, although individual cxperimcnts required, on occasion, a four-second exposure before no growth would oepur in the recovery broth. Streptococcus fscabis exhihitcd the most erratic results, for out of seventeen runs only eight showed no skips. The misses ranged from one to nine seconds, with the average being six seconds. Thus, for effectire steriliznt.ion of broaches, a nine-second exposure is required; this dcmonstratcs the heat-resistant property of this organism. Ho&&c alhicwns was the most heat-sensitive organism used, since there were no skips recorded and only a one-second immersion in the glass head sterilizer was required to ol)t;lin negative results in the rccoverp broth. ‘Johnson R- Johnson, tBa.ltin~orr Biological gDifco Twboratories.
New Brunswick, Laboratories, Detroit. Michigan.
New Jersey, Inc., Baltimorrt,
manufacturers. Maryland.
TABLE -
0. s., 0. M. & 0. 1'. March, 1959
SPBIXQ
356 II.
RESPONSE
OE' MICROORGANISJIS
ON METAL
BROACH
CAKRIEKS
'1'0 STERILIZING
1‘1~1~s
. TIME ORGANISM
Eschsrickia COG
Staphylococcus
&IUS
Streptococcus
f ecnlis
Mon.ilia
alhicans
I c*j1/2[3)4/5/617
+--+ + - + 4 + ,. .+ +--+---
f
-
-
-
+ + . + .~ +,.-. ++ + +---
- , + __
+
+
--
--
+
(SECONDS)
18lYllO
--__ . ^- ---
--
._ _ --._ _-
-
-
-
-
-
-
+
++++ *+ +i-+ ++i- + + + +++ + + -I. + 4 + + ++++i++++ + + + , + + + + -I- + + + + ++i i + + + ++++ --+ + -6 + + - - + .I + + - - +l+, +-+-I+ i- + - + - + + + + .4 +++ +++4 ii+ ,. - -. + + +..-
_-
+--+ .- +.-f---
-I -. ---
-
-
+A--+ + -b 4 c , .. +++ i -. 4 +-- , - - - - + ----- - - .
CIJJLI'URE MEDIC'M
TEMPERATURE STERILIZING
(DEGREES 1 ROOXl
215 215 21.0 210 213 213
i: 21 23 23
soy soy soy soy
215 “15 211
2-k 24 25
211
2.5
T. 1‘. 1’. 1’.
soy SO.” inf. inf.
210 210 21.3 213
21 21 2.1 03
1’. 1’. ‘I-. T. T. ‘I‘. I’. T. T. T. T.
so,v soy soy soy SO) snv so;s& so\: so\, so’,,
212 “12 210 215 215 215 “11
2.5 25 24 24 “4 “4 ‘>‘> --
T.
so;
T.
soy
T. 'I?. T. I'. V .
soy soy soy inf. inf .
'I?. T. I?. I'.
CT
24
T. so; T. so; T. s& V.
in2.
v.
inf.
T. so) I?. soy T. T. T.
soy so> snv
Key to Abbreviations: T. SOY = Trypticase soy broth. V. inf. z Veal infusion broth. *c = Control.
Table III shows the time rcquircd for sterilization of contaminated paper points. For all test organisms, a one-second immersion was sufficient for effective sterilization ; however, this was contrary to the five- to ten-second exposure noted by other investigators. CONCLUSION
Design chsngcs to minimize tho temperature variation would suggest heating coils ahont, the entire depth of the unit so as to maintain a high uniform temperature, even at the 3 cm. depth which is equal to the length of an average paper point. This unit was so constructed that it had a funnel-shaped opening onto which, the manufacturer claims, a disk containing absorbent points and broaches ma.y be placed, thus effecting partial sterilization. However,
BACTERIAL TABLE __~--
111.
BESPONSE
EVALUATION or
MICROORGANISMS
erichia
coli
ON PALER
+--+--+--f---
Slflpl~gzococcus
frcnlin
=
broth
WRS
-
f---
-----
f--f--+ - +-------+ .- -
-
------- -
-
--
-.
-
-
-
-
-
-
_--
---
+---
soy
---
-_
-
f-----
*c
CARRIERS
--
+-----+---
nlhicmns
Trypticase
YO~NT
as
the
TO STERILIZATION
culture
(DEGREES I
T~all;s C.) ROOM
213 213 210 210
23 23 22 22
212 212 21 I 211
22 22 23 23
213 213 215 215 215 310
22 22 24 24 24 21
310
22 24 24 22
270 213 213
--
une~l
357
STERILIZER
TEhfPERATURE STERILIZING
-------
f-----+--+ ._ -
Monilia
BEAD
f--------
fllhlrs
Slrrptococcun
GLASS
TIME (SECONDS) c*)1\2~3[4~5[6]7~8~
ORGANIShl Bsch
OF
merlium
in
this
-
experiment.
Control.
one disadvantage presented is tha.t in order to insert an instrument into the glass beads it is necessary fir& to remove the dish, always with the possibility of dropping it. Also this sterilizer facilitates heat loss by nature of the la.rge aperture. These two disadvantages can be corrected by constricting the opening to 3/4 inch, instead of 11/z inches, and by inserting a small test. tube into the glass beads. In this way it is possible to place instruments into t.he tube and partially sterilize them without having to remove them to insert instruments into the glass beads. For effective sterilization of broaches contaminated with Escherichin coli a. one-second exposure was required ; Staphylococcus albzcs required t,wo seconds, Monilirb abbicans required one second, and Streptococcus fecalis required nine seconds. Thus, for sterile broaches, a nine-second immersion in the glass bead sterilizer is required. Absorbent points inoculated with all organisms used in this study were innocuous after a one-second exposure. Therefore, the time needed for effective sterilization of all points is one second. REFERENCES
1. Boak,
8. D.:
Lab
Test Efirncy
2. E’inlll;y~8J;f5;
3. Flaherty,‘H.
Western D. J. 30: 23, 1916. Glass Bead Sterilization, J. Am. S., Sorin, S., and Brown, H.: A Temperature trolled Root Canal Sterilizers Using Molten L.
SURG.,
6. Stewart,
Molten Met,al Metal and Ball
Flalwrty
of Molten
Sterilizer,
Mil.
T).
Retrings
and
Media,
I.:
PATH. N.
Canal
4:
Rrit.
148,
1921.
D. J. 98:
ORAL
MED.
& ORAL
PATH.
11:
37,
Dent. A. 51: 380, 1955. Analysis of Thermostatically Metal, Glass Beads, or Salt,
3: 256, 1950. B., and Stewart,
Instmments,
J.
G. G.:
Ontario
ConORAL
1958.
G. G., and Williams, N. B.: Preliminary Report for Sterilizing Root Canal Instruments and Materials,
7. Williams,
J.
RI:
4. (+rosaman,
5. Oliet.,
on
Molten Metal-A D. A. 27: 283,
on the Efficacy ORAL
Medium 1950.
SURG.,
for
of Molten ORAL
Sterilization
MED.
Metal & ORAL
of Root
.
.
.
.
.
BACTERIOLOGIC FOR
.
.
.
.
EVALUATION
.
.
.
.
OF THE
.
.
.
GLASS
.
.
BEAD
.
.
.
.
.
STERILIZER
ENDODONTICS
Paul A-. Spring,
D.D.S.,”
Utica, N. Y.
suggested molten metal as a potential sterilizing agent for use in the dental office. Roak’ concluded that a five-second exposure of metal instruments contaminated with vegetative and sporulated organisms in molten metal was an effective means of sterilization ; swabs with vegetative organisms required five seconds, but a ten-second exposure was required to destroy spores on cotton swabs. He used Streptococcus viridans, Streptococcus hemolyticus, Staphylococcus sp., and Bacillus subtilis. No
F
LAHERTY3
*Resident
in Oral
Surgery,
Buffalo
Veterans 353
Administration
Hospital.
354
0 5.. 0. hl. a 0. I’.
SPEING
.\I.trrh.
I’li’i
for effective heat transfer, a tempcraturc range of 225 to 250° C., and a temptI-nturc differential of 30° c’. within the sterilizer. illthougll neither organisms nor time intervals were specified, Grossman suggested that the duration of heat exposure should be equivalent to the conventional timcbx used for molten metal sterilization. 11 temperature analysis of thermostatically controlled root, cana, sterilizers was rcportcd by Olict, Sorin, and Brown,” who drtermincd tha.t a. definite tcmperaturc gradient was exhibited between the base and snrfact and the outer circnmferencc and center of the ~11 of all sterilizers. Nanufacturcrs’ literature* suggested that with 1 mm. solid glass sphcrcs and a tcmperaturc of GO0 F’., a three- to five-second esposnrc -for metal broaches and a t,en-second exposure for paper or cotton material was rquirrtl for sterilization of eontaminatcd mat,CriiIlS. MATERIALS
AiXD
XETHOD?:
A commercial glass bead sterilizert was used in the following study. Sterilizer temperatures were measured with a mercury-filled thermometer. Temperature strata as a function of immersion dept.h were observed and arc recorded in Table I with emergent. stem corrections applied to the data.* TABLE
I.
TEMPERATIJRE
VARIATIOK
AS A FUKCTION
OF IMUERSION
DEPTH
Deuth--cm.
Because of the temperature strata, all broaches and paper points mere immersed to the bottom of the sterilizer, to ensure a more constant heat exposure of the test instruments. *Electra-ball iEmergent
sterilizer, stem correction
Union is
Broacn 11.5’
Co., C.
Inc.,
New
York,
New
York.
Volume Number
BACTERIAL
I2 3
EVALUATION
OF
GLASS
READ
STERILIZER
355
Efficiency of heat sterilization by the ball sterilizer was determined on an ‘Lall-or-none” basis. Dental broaches, paper points,” and associated equipment, were autoclavcd at 121.O C. for twenty minutes and contaminated by seizing the broaches or points with sterile forceps and immersing them in a They were removed after thirty twenty-four-hour culture of test organisms. seconds’ exposure and placed upon a sterile paper filter in a covered Petri Then the contaminated dental materials were dish lo remove cxccss moisture. removed with forceps from the P&i plates and held among the glass bends in the ball sterilizer for varying times; they were rcmovcd, dropped into rccovery broth, and incubated at 37O C., and the results were recorded after seventy-t,wo hours. The results of these experiments arc shown in Tables II and II r. Recovery broth used in these cxpcrimcnts was eith(ir t rypticasct soy or veal infusion.$ In all cases, cxpcrirncntally contaminated hroachcs and paper points grew well in both types of recovery broth. Test organisms used in this study were Streptococcus fecnlis (an cnterococcus), Stnph~ylococcus CITIHL.S, Escherichirr. coli, and Monilirl dlkrrns. RIBTiLTS
AND
DISCUSSION
The commercial ball stcrilizcr used in these experiments displayed approximately a 5Z” C. temperature variation (corrected for emergent stem) between the bottom of the unit and the surface of the glass balls, as charted in Table I. This variation was surprising but not unexpected, since the construction of the unit placed all heating coils in the bottom with a modified Dewar flask as the container. Irrespective of ambient temperatures, the highest tcmpcratures noted in this study were between 210 and 215’ C. at the floor of the unit,. Standardization of the technique result,ed in the introductiou of all test substances to the bottom of the unit, a 6 cm. immersion depth. At this position daily variations in trmpcratures ~vcro minimized to an incrrincnt of i4o c. Table 11 shows the time exposure required to sterilize contaminated metal I)~~a~hs. Wit.h E. coli as the test organism, broaches were sterile with ;I oncsecond exposure to 211° C. In a few instances, a t,wo- or three-second exposure wa.s required to effect sterilization, in accord with the two-second oxposurc designated bay &wart and Williams. Stwphylococcus dbus n-as usually destroyed by a two-second exposure, although individual cxperimcnts required, on occasion, a four-second exposure before no growth would oepur in the recovery broth. Streptococcus fscabis exhihitcd the most erratic results, for out of seventeen runs only eight showed no skips. The misses ranged from one to nine seconds, with the average being six seconds. Thus, for effectire steriliznt.ion of broaches, a nine-second exposure is required; this dcmonstratcs the heat-resistant property of this organism. Ho&&c alhicwns was the most heat-sensitive organism used, since there were no skips recorded and only a one-second immersion in the glass head sterilizer was required to ol)t;lin negative results in the rccoverp broth. ‘Johnson R- Johnson, tBa.ltin~orr Biological gDifco Twboratories.
New Brunswick, Laboratories, Detroit. Michigan.
New Jersey, Inc., Baltimorrt,
manufacturers. Maryland.
TABLE -
0. s., 0. M. & 0. 1'. March, 1959
SPBIXQ
356 II.
RESPONSE
OE' MICROORGANISJIS
ON METAL
BROACH
CAKRIEKS
'1'0 STERILIZING
1‘1~1~s
. TIME ORGANISM
Eschsrickia COG
Staphylococcus
&IUS
Streptococcus
f ecnlis
Mon.ilia
alhicans
I c*j1/2[3)4/5/617
+--+ + - + 4 + ,. .+ +--+---
f
-
-
-
+ + . + .~ +,.-. ++ + +---
- , + __
+
+
--
--
+
(SECONDS)
18lYllO
--__ . ^- ---
--
._ _ --._ _-
-
-
-
-
-
-
+
++++ *+ +i-+ ++i- + + + +++ + + -I. + 4 + + ++++i++++ + + + , + + + + -I- + + + + ++i i + + + ++++ --+ + -6 + + - - + .I + + - - +l+, +-+-I+ i- + - + - + + + + .4 +++ +++4 ii+ ,. - -. + + +..-
_-
+--+ .- +.-f---
-I -. ---
-
-
+A--+ + -b 4 c , .. +++ i -. 4 +-- , - - - - + ----- - - .
CIJJLI'URE MEDIC'M
TEMPERATURE STERILIZING
(DEGREES 1 ROOXl
215 215 21.0 210 213 213
i: 21 23 23
soy soy soy soy
215 “15 211
2-k 24 25
211
2.5
T. 1‘. 1’. 1’.
soy SO.” inf. inf.
210 210 21.3 213
21 21 2.1 03
1’. 1’. ‘I-. T. T. ‘I‘. I’. T. T. T. T.
so,v soy soy soy SO) snv so;s& so\: so\, so’,,
212 “12 210 215 215 215 “11
2.5 25 24 24 “4 “4 ‘>‘> --
T.
so;
T.
soy
T. 'I?. T. I'. V .
soy soy soy inf. inf .
'I?. T. I?. I'.
CT
24
T. so; T. so; T. s& V.
in2.
v.
inf.
T. so) I?. soy T. T. T.
soy so> snv
Key to Abbreviations: T. SOY = Trypticase soy broth. V. inf. z Veal infusion broth. *c = Control.
Table III shows the time rcquircd for sterilization of contaminated paper points. For all test organisms, a one-second immersion was sufficient for effective sterilization ; however, this was contrary to the five- to ten-second exposure noted by other investigators. CONCLUSION
Design chsngcs to minimize tho temperature variation would suggest heating coils ahont, the entire depth of the unit so as to maintain a high uniform temperature, even at the 3 cm. depth which is equal to the length of an average paper point. This unit was so constructed that it had a funnel-shaped opening onto which, the manufacturer claims, a disk containing absorbent points and broaches ma.y be placed, thus effecting partial sterilization. However,
BACTERIAL TABLE __~--
111.
BESPONSE
EVALUATION or
MICROORGANISMS
erichia
coli
ON PALER
+--+--+--f---
Slflpl~gzococcus
frcnlin
=
broth
WRS
-
f---
-----
f--f--+ - +-------+ .- -
-
------- -
-
--
-.
-
-
-
-
-
-
_--
---
+---
soy
---
-_
-
f-----
*c
CARRIERS
--
+-----+---
nlhicmns
Trypticase
YO~NT
as
the
TO STERILIZATION
culture
(DEGREES I
T~all;s C.) ROOM
213 213 210 210
23 23 22 22
212 212 21 I 211
22 22 23 23
213 213 215 215 215 310
22 22 24 24 24 21
310
22 24 24 22
270 213 213
--
une~l
357
STERILIZER
TEhfPERATURE STERILIZING
-------
f-----+--+ ._ -
Monilia
BEAD
f--------
fllhlrs
Slrrptococcun
GLASS
TIME (SECONDS) c*)1\2~3[4~5[6]7~8~
ORGANIShl Bsch
OF
merlium
in
this
-
experiment.
Control.
one disadvantage presented is tha.t in order to insert an instrument into the glass beads it is necessary fir& to remove the dish, always with the possibility of dropping it. Also this sterilizer facilitates heat loss by nature of the la.rge aperture. These two disadvantages can be corrected by constricting the opening to 3/4 inch, instead of 11/z inches, and by inserting a small test. tube into the glass beads. In this way it is possible to place instruments into t.he tube and partially sterilize them without having to remove them to insert instruments into the glass beads. For effective sterilization of broaches contaminated with Escherichin coli a. one-second exposure was required ; Staphylococcus albzcs required t,wo seconds, Monilirb abbicans required one second, and Streptococcus fecalis required nine seconds. Thus, for sterile broaches, a nine-second immersion in the glass bead sterilizer is required. Absorbent points inoculated with all organisms used in this study were innocuous after a one-second exposure. Therefore, the time needed for effective sterilization of all points is one second. REFERENCES
1. Boak,
8. D.:
Lab
Test Efirncy
2. E’inlll;y~8J;f5;
3. Flaherty,‘H.
Western D. J. 30: 23, 1916. Glass Bead Sterilization, J. Am. S., Sorin, S., and Brown, H.: A Temperature trolled Root Canal Sterilizers Using Molten L.
SURG.,
6. Stewart,
Molten Met,al Metal and Ball
Flalwrty
of Molten
Sterilizer,
Mil.
T).
Retrings
and
Media,
I.:
PATH. N.
Canal
4:
Rrit.
148,
1921.
D. J. 98:
ORAL
MED.
& ORAL
PATH.
11:
37,
Dent. A. 51: 380, 1955. Analysis of Thermostatically Metal, Glass Beads, or Salt,
3: 256, 1950. B., and Stewart,
Instmments,
J.
G. G.:
Ontario
ConORAL
1958.
G. G., and Williams, N. B.: Preliminary Report for Sterilizing Root Canal Instruments and Materials,
7. Williams,
J.
RI:
4. (+rosaman,
5. Oliet.,
on
Molten Metal-A D. A. 27: 283,
on the Efficacy ORAL
Medium 1950.
SURG.,
for
of Molten ORAL
Sterilization
MED.
Metal & ORAL
of Root