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Evaluation of a digital pulp tester
endodontics Editor: MILTON SISKIN, D.D.S. College of Dentistry The University of Tennessee 847 Monroe Avenue Memphis, Tennessee 38163
Evaluation of a digital pulp tester Robert L. Cooley, D.M.D., M.S.,* John Stilley, D.D.S.,** and Richard h4. Lubow, D.M.D., M.S., *** San Antonio, Texas, and Rapid City, S.D. An evaluation of a new-generation digital pulp tester revealed some significant conventional, manually operated type. Its automatic operation and comfortable could make this instrument a valuable addition to the dental armamentarium. (ORALSURG. 58~437-442, 1984)
T
he determination of pulpal vitality has been an integral part of dental practice for many years. The status of the pulp is an essential diagnostic step in differentiating between periodontal or pulpal etiology of a periapical or radicular radiolucency. The pulpal status may also be important in other common situations, such as the periodic monitoring of teeth subjected to traumatic injuries or the initial assessment of prosthetic abutments to gain helpful information about long-term prognosis. To assessvitality in these situations, the clinician may use electric pulp testing, thermal pulp testing, or both. The electric pulp tester has been used in dentistry since 1867 and has evolved over the years into the present electronic digital pulp tester. Early electric pulp testers were bulky and cumbersome. Eventually, battery-powered models were introduced, and these exhibited a more compact design. Characteristics required of a pulp tester, as well as variations in design theory, were described by The views expressed herein are those of the authors and not necessarily those of the United States Air Force or the Department of Defense. *Dental Investigative Service, Brooks Air Force Base, San Antonio, Texas. **Chief, Professional Services, United States Air Force Hospital, Ellsworth Air Force Base, Rapid City, S. D. ***Assistant Chairman, Department of Periodontics, USAF Medical Center, Keesler Air Force Base, Biloxi, Miss.
advantages over the stimulation of the tooth
Mathews and Searle’ in their 1974 evaluation of sevenelectric pulp testers. Technologic progress and continued sophistication have now produced the electronic digital pulp tester. If the digital pulp tester is indeed an improved instrument as compared to previous models, it should be accurate, should have relatively universal application, and should perform dependably. This study was developed to evaluate these parameters and provide the clinician with an understanding of the capabilities and limits of the electronic digital pulp tester. MATERIALS
AND METHODS
The digital pulp tester* evaluated in this study is shown in Fig. 1. This pulp tester is operated on four penlight cells and is different from other conventional pulp testers in that the electronic circuitry is contained in a central unit measuring 4 by 7 inches. The test probe is connected to the central unit by a 70-inch cord. The control unit contains the digital display, reading from 0 to 80, and replaces the rheostat found on conventional pulp testers, which increases the electrical stimulus. This pulp tester automatically increasesthe intensity of the electrical stimulus, and the rate at which it can be increased is adjusted by a control on the central unit. Other unique features of this digital pulp tester which are *Analytic Technology pulp tester, Redmond, Wash. 437
438
Cooley, Stilley, and Lubow
Oral SW&. October,I984
Fig. 1. Digital pulp tester consisting of the central control unit and the probe which is placed on top. The digital display (black rectangle on left front panel) indicates the intensity of the electrical stimulus in red numbers.
Fig. 2. Electrical stimulus from the digital pulp tester as displayed on the oscilloscope screen. This instrument creates ten negative pulses followed by a nonstimulus period. The last pulse of a series can be seen on the left, followed by a nonstimulus period, followed by ten negative pulses.
not found on conventional units include the following: l Turns on automatically when the probe makes contact with the tooth. l Turns off automatically when the probe is removed from the tooth. l Indicates, via digital display, the stimulus level at which the tooth responded. The display automatically resets to 0 after removal from the tooth. l Red light on the probe indicates when electrical contact has been made and also when maximum electrical stimulus is reached. l Voltage is electronically stabilized so that when the battery voltage drops with use, the pulp tester output will remain constant. l Low battery voltage is indicated on the digital display by two flashing dots. Continuous lighting of the dots and disappearance of the digits indicate depleted batteries. This pulp tester was evaluated in both a laboratory and a clinical setting. In the laboratory, the following tests were performed: (1) Activation of the “low battery” indicator (flashing dots). The batteries were removed from the pulp tester and a variable power supply* was attached to provide power. The voltage from the variable power supply was decreased until the “low battery” indicator was activated. This was repeated three times, and the voltage was recorded. (2) Activation of the “depleted battery” indicator (continuous red dots and disappearance of the numbers). This test was performed in the same manner as
that for the activation of the “low battery” indicator. It recorded the voltage at which the continuous red dots were activated and the numbers disappeared from the digital display. (3) Ability to stabilize output voltage as battery voltage decreased. An oscilloscope* was used to measure the output voltage of the pulp tester. Two sets of batteries were used to test this function. The first set was new and provided 6.3 volts. The other set was used until the voltage level dropped to 4.8 volts. The output voltages from the pulp tester were monitored on the oscilloscope screen (Fig. 2), and at each lo-volt increment (except for the first interval) the number on the digital display was recorded. This was performed separately for the new and used batteries and was repeated twice for each set. If the output voltage is stabilized, then the number on the digital display should be the same for both the new and used batteries at each lo-volt increment. Clinically, the pulp tester was evaluated under the following conditions: 1. It was applied to thirty nonvital, endodontically treated teeth. This was done to determine if the intensity of the electrical stimulus was such that it would create a false-positive result. Each tooth was tested twice. 2. The ability of the digital pulp tester to make electrical contact and automatically start operation was evaluated under the following conditions: (a) on
*Tektronic
*Tektronix
501 power module, Tektronix,
Inc., Beaverton, Ore.
434 storage oscilloscope, Tektronix,
Inc.
Evaluation
Volume 58 Number 4
Table I. Effect of decreasing battery voltage on pulp tester output voltage Pulp tester outpui voltage (VOh)
15 20 30 40 50 60 70 80 90 100 110 120 130 140 150
_
6.3 volts* 14 20 29 33 36 38 40 46 54 57 62 65 72 80 80
4.8 volisf 10 18 27 32 34 38 39 40 50 55 58 62 68 75 80
439
Table II. Responseof endodontically treated teeth to digital pulp tester Tooth No.
Digital display reading at two battery voltages
of digital pulp tester
13 18 19 8 23 19 30 19
(
Response None None None None None None None Yes* Yest None None None None None None
1
Tooth No. 3 14 19 3 28 30 30 23 24 25 19 30 10 3 8
( Response None None None None None None None None None None None None None None None
*When retested, two negative responseswere obtained. I’When tooth was isolated with rubber dam on the mesial and distal, aspects,no responsewas elicited.
*Voltage dropped to 6.1 when the tester was operating. tVoltage dropped to 4.3 when the tester was operating.
ten vital teeth with no electrode media (electrolyte); (b) on ten porcelain facings; (c) with the operator wearing rubber gloves; and (d) with the operator using one hand. (Neither the hand holding the probe nor the other hand touched the patient.) 3. The sensation of the electrical stimulus was determined on four dentists under the following conditions: (a) with the probe applied to an anterior tooth; (b) with the probe applied to gingiva in an anterior region; and (c) with the vestibule filled with saline solution and the probe placed in the saline solution (but not touching tissue). RESULTS
The results from the laboratory portion of this study are as follows: 1. The “low battery” indicator was activated when the voltage dropped to 3.6 or 3.7 volts and was displayed as two flashing dots on the digital display (new battery voltage is usually 6 volts or more). 2. The “depleted battery” indicator was activated when the voltage dropped to 3.5 volts and was displayed as two continuous red dots and the number disappeared from the digital display. 3. The ability to stabilize outp,ut voltage with a drop in battery voltage is shown in Table I. When battery voltage dropped from 6.3 volts to 4.8 volts, stabilization was not complete but very close. The results from the clinical portion of this study are as follows: 1. When thirty nonvital, endodontically treated
teeth were tested, only two gave a positive response that could result in a false-positive determination (Table II). One of these gave a negative response when retested two additional times. The other gave a negative responsewhen isolated from adjacent teeth with strips of rubber dam. 2. The ability of the pulp tester to make electrical contact as indicated by the red light on the probe (Fig. 3) is shown in Table III. (a) When no electrode media was used on the tooth or probe, the pulp tester would not make electrical contact with any of the ten teeth and would not automatically start operation. (b) On the ten porcelain facings, the pulp tester would not make electrical contact or automatically start operation. (c) The digital pulp tester would not make electrical contact or begin operation when the operator was wearing gloves. (d) The pulp tester would not operate when the operator held the probe with one hand and did not touch the patient. However, placing the fingers of this hand on the patient’s lips established contact and the tester operated normally. 3. When the pulp tester was evaluated on four dentists, the following subjective responses were elicited: (a) On an anterior tooth, three dentists indicated that it created a sensation of vibration or tingling. The fourth felt a pulsating sensation along with a sensation of cold air.
440
Cooley, Stilley, and Lubow
Oral Surg. October, 1984
TaMs III. Lack of electrode media/porcelain facings:
Effect on ability of pup tester to make electrical contact
Type of test
Lack of electrode media (10 teeth tested) Porcelain facings (10 teeth tested)
Electrical contact established
None None
5. The digital display provides instant, easy readable information. Dieadvantages Fig. 3. Redlight (arrow)on the probehandleis activated
whenelectricalcontactis established.It flasheson and off when the maximum stimulus has beenreached.
(b) On anterior gingiva, two dentists indicated that it felt somewhat like a needle, with the sensation growing in intensity. Two others said that it was like little impulses (or pulsations) growing in intensity. (c) When vestibule was filled with saline solution, none of the four dentists felt any sensation with this procedure. DlSCUSSlON
The digital pulp tester was used by a group of ten dentists for 6 months. During this period of time, the following advantages and disadvantages were noted: Advantages
1. Intensity of the stimulus is such that patients find it more comfortable. When it was evaluated on four dentists, their impression was one of a tingling, vibrating, or pulsating sensation. 2. The red indicator light on the probe (Fig. 3) indicates when electrical contact is established with the tooth and then flashes on and off when the tester reaches maximum stimulus. 3. The unit will not turn on automatically and start the electrical stimulus until electrical contact is established with the tooth. This prevents jolting the patient, as might occur with a conventional, manually controlled pulp tester in those situations in which contact is not made until the tester has reached a higher voltage setting. 4. The unit turns on and off automatically when the probe is applied to the tooth. It is easy and quick to operate, as there are no buttons or controls that require manipulation for operation.
1. The probe tip is removable and easily falls out of the handle. Several attempts were made to adjust the probe tip so that it would be more secure in the handle, but without success. 2. Batteries may fall out of the battery holder, giving the impression that the unit is inoperable. There is a rubber pad designed to retain the batteries, but on two occasions they worked loose and the tester did not operate. 3. The speedcontrol setting for adjusting the rate of increase in the electrical stimulus does not have a label to indicate which direction is fast and which is slow. 4. The pulp tester will not operate if the dentist wears rubber gloves. 5. This pulp tester is considerably more expensive than others. The first three disadvantages are not great ones and could be corrected by the manufacturer. Most dentists do not wear gloves routinely, so this disadvantage is not a big obstacle. The price may be the biggest disadvantage; however, it is offset by the advantages of the unit. Matthews and Searle’ addressed the problem of false-positive results from nonvital teeth. In their review of the literature, they found two studies on this subject. Seltzer and associates*compared pulp tester data with histologic findings and found that five of eighteen nonvital teeth gave a positive response.In a similar study, Johnson and co-workers3 reported that fifteen of thirty-five nonvital teeth gave a positive response.When the digital pulp tester was applied to thirty nonvital, endodontically treated teeth, only two gave a positive response.This test was performed to determine the possibility of eliciting false-positive results. This could occur if the electrical stimulus is strong enough to stimulate the periodontium or if the electrical stimulus travels to adjacent teeth. In the caseof the maxillary right lateral
Evaluation of digital pulp tester 441 &&or, which gave a positive result, the stimulus apparently did travel to an adjacent tooth. When the lateral incisor was isolated from the adjacent teeth with narrow strips of rubber dam, there was no sensationwith the maximum stimulus. It appearsthat the possibility of creating a false-positive response(on a nonvital tooth) is small but doesexist. If there is any doubt, strips of rubber dam can be placed on the proximal surfacesand the test repeated. There is also one situation in which this device may give a flase-negative response(no responseon a vital tooth). This situation was noted during evaluation of the “low battery” and “depleted battery” indicators. When the battery voltage dropped to 4.0 volts (as measured with the pulp tester operating), the digital display continued to count upward, but the output voltage (measured with the oscilloscope) did not increase with the numbers on the digital display. In this situation, the operator would think that the pulp tester is operating normally, but the electrical stimulus would not be increasing. It could give the operator the impression that a tooth is nonvital when, in fact, it is vital. However, there was only one specific battery voltage at which this could occur, and it can be circumvented by replacing the batteries periodically. The necessity of an electrode medium has been addressed in several studies. Cooley and Robison4 evaluated toothpaste, water, and a commercial electrode gel and found little difference in the three, although toothpaste was the least effective. However, they also found that little voltage or current was passed to the tooth without an electrode medium. Martin, Ferris, and MazzellaS demonstrated a definite increase in the stimulus transmitted when an electrode medium is used. They also found that the type of medium is not significant but that it should have a water base. The digital pulp tester evaluated in this study would not automatically start operation without an electrode medium. It was placed on ten teeth without any electrolyte present and would not operate. It is interesting to note that when the pulp tester was applied to saline solution in the vestibule and allowed to reach maximum stimulus, no sensation was felt. This phenomenon was noted in another study’ with another brand of pulp tester. This probably occurs becausethe saline solution dispersesthe electrical stimulus over a wide area. For this reason, teeth should be completely dry during testing to prevent a false result. The evaluation of this digital pulp tester’s ability to stabilize output voltage as the battery voltage drops indicated that it did not provide complete
stabilization. When the battery voltage dropped from 6.3 volts to 4.8 volts, there were some minor variations in the output voltage. The voltage variations should not pose a problem. An electric pulp tester should be used only to determine vitality or nonvitality and not for diagnosis of pulp conditions. The clinician should not try to quantitate the response between teeth at any particular digital reading, as other variables may be present. The control for adjusting the rate of increase of the electrical stimulus did not have a label indicating which direction increased the speedand which direction decreasedthe speed.This originally causedsome patients to be jolted when the control was unknowingly set on “fast.” The rate of stimulus increase was so fast that the stimulus became uncomfortable before the probe could be removed from the tooth. However, this problem can be solved by adjusting the speed control before pulp testing is attempted. The operator can place his finger on the probe tip while holding the handle in the same hand. This will activate the pulp tester and the digital display. The speedcontrol can be adjusted at this time. Once the operator determines the speedthat is convenient and practical, a white mark can be placed on the control so that this position can be maintained. This digital pulp tester eliminates some of the variables associatedwith electric pulp testing, particularly those concerning establishment of electrical contact. Its simple operation allows the dentist to keep both hands steady and on the patient. It also permits constant observation of the patient for any signs of change. SUMMARY
A digital pulp tester was evaluated with a series of laboratory tests as well as with clinical usage. The ability of the pulp tester to operate automatically, increase the intensity of the stimulus automatically, stabilize output voltage, and indicate low or depleted batteries was evaluated. The pulp tester performed well in all these areas. Clinically, it was found to perform consistently, dependably, accurately, and easily for all dentists who evaluated its use. The only notable problem was the inability to use this unit while wearing surgical gloves. All in all, the digital pulp tester could be a most valuable addition to the dental armamentarium. REFERENCES
1. Matthews B, Sea& B: Some observations on pulp testers. Br Dent J 137: 307, 1974. 2. Seltzer S, Bender IB, Ziontz M: The dynamics of pulp inflammation: correlations between diagnostic data and actual histologic findings in the pulp. ORAL SURG 16: 846, 1963.
442 Cooley, Stilley, and Lubow 3. Johnson RH, Dachi S, Haley J: Pulpal hyperemia-a correlation of clinical and histologic data from 706 teeth. J Am Dent Assoc 81: 108, 1970. 4. Cooley RL, Robison SF: Variables associated with electric pulp testing. ORAL SURG 50; 66, 1980. 5. Martin H, Ferris C, Mazzella W: An evaluation of media used in electric pulp testing. ORAL SURG 27: 374, 1969.
Oral Surg. October, 1984 Reprint requesls 10:
Dr. Robert L. Cooley USAF SAM/NGD Brooks AFB, TX 78235
Evaluation of a digital pulp tester Robert L. Cooley, D.M.D., M.S.,* John Stilley, D.D.S.,** and Richard h4. Lubow, D.M.D., M.S., *** San Antonio, Texas, and Rapid City, S.D. An evaluation of a new-generation digital pulp tester revealed some significant conventional, manually operated type. Its automatic operation and comfortable could make this instrument a valuable addition to the dental armamentarium. (ORALSURG. 58~437-442, 1984)
T
he determination of pulpal vitality has been an integral part of dental practice for many years. The status of the pulp is an essential diagnostic step in differentiating between periodontal or pulpal etiology of a periapical or radicular radiolucency. The pulpal status may also be important in other common situations, such as the periodic monitoring of teeth subjected to traumatic injuries or the initial assessment of prosthetic abutments to gain helpful information about long-term prognosis. To assessvitality in these situations, the clinician may use electric pulp testing, thermal pulp testing, or both. The electric pulp tester has been used in dentistry since 1867 and has evolved over the years into the present electronic digital pulp tester. Early electric pulp testers were bulky and cumbersome. Eventually, battery-powered models were introduced, and these exhibited a more compact design. Characteristics required of a pulp tester, as well as variations in design theory, were described by The views expressed herein are those of the authors and not necessarily those of the United States Air Force or the Department of Defense. *Dental Investigative Service, Brooks Air Force Base, San Antonio, Texas. **Chief, Professional Services, United States Air Force Hospital, Ellsworth Air Force Base, Rapid City, S. D. ***Assistant Chairman, Department of Periodontics, USAF Medical Center, Keesler Air Force Base, Biloxi, Miss.
advantages over the stimulation of the tooth
Mathews and Searle’ in their 1974 evaluation of sevenelectric pulp testers. Technologic progress and continued sophistication have now produced the electronic digital pulp tester. If the digital pulp tester is indeed an improved instrument as compared to previous models, it should be accurate, should have relatively universal application, and should perform dependably. This study was developed to evaluate these parameters and provide the clinician with an understanding of the capabilities and limits of the electronic digital pulp tester. MATERIALS
AND METHODS
The digital pulp tester* evaluated in this study is shown in Fig. 1. This pulp tester is operated on four penlight cells and is different from other conventional pulp testers in that the electronic circuitry is contained in a central unit measuring 4 by 7 inches. The test probe is connected to the central unit by a 70-inch cord. The control unit contains the digital display, reading from 0 to 80, and replaces the rheostat found on conventional pulp testers, which increases the electrical stimulus. This pulp tester automatically increasesthe intensity of the electrical stimulus, and the rate at which it can be increased is adjusted by a control on the central unit. Other unique features of this digital pulp tester which are *Analytic Technology pulp tester, Redmond, Wash. 437
438
Cooley, Stilley, and Lubow
Oral SW&. October,I984
Fig. 1. Digital pulp tester consisting of the central control unit and the probe which is placed on top. The digital display (black rectangle on left front panel) indicates the intensity of the electrical stimulus in red numbers.
Fig. 2. Electrical stimulus from the digital pulp tester as displayed on the oscilloscope screen. This instrument creates ten negative pulses followed by a nonstimulus period. The last pulse of a series can be seen on the left, followed by a nonstimulus period, followed by ten negative pulses.
not found on conventional units include the following: l Turns on automatically when the probe makes contact with the tooth. l Turns off automatically when the probe is removed from the tooth. l Indicates, via digital display, the stimulus level at which the tooth responded. The display automatically resets to 0 after removal from the tooth. l Red light on the probe indicates when electrical contact has been made and also when maximum electrical stimulus is reached. l Voltage is electronically stabilized so that when the battery voltage drops with use, the pulp tester output will remain constant. l Low battery voltage is indicated on the digital display by two flashing dots. Continuous lighting of the dots and disappearance of the digits indicate depleted batteries. This pulp tester was evaluated in both a laboratory and a clinical setting. In the laboratory, the following tests were performed: (1) Activation of the “low battery” indicator (flashing dots). The batteries were removed from the pulp tester and a variable power supply* was attached to provide power. The voltage from the variable power supply was decreased until the “low battery” indicator was activated. This was repeated three times, and the voltage was recorded. (2) Activation of the “depleted battery” indicator (continuous red dots and disappearance of the numbers). This test was performed in the same manner as
that for the activation of the “low battery” indicator. It recorded the voltage at which the continuous red dots were activated and the numbers disappeared from the digital display. (3) Ability to stabilize output voltage as battery voltage decreased. An oscilloscope* was used to measure the output voltage of the pulp tester. Two sets of batteries were used to test this function. The first set was new and provided 6.3 volts. The other set was used until the voltage level dropped to 4.8 volts. The output voltages from the pulp tester were monitored on the oscilloscope screen (Fig. 2), and at each lo-volt increment (except for the first interval) the number on the digital display was recorded. This was performed separately for the new and used batteries and was repeated twice for each set. If the output voltage is stabilized, then the number on the digital display should be the same for both the new and used batteries at each lo-volt increment. Clinically, the pulp tester was evaluated under the following conditions: 1. It was applied to thirty nonvital, endodontically treated teeth. This was done to determine if the intensity of the electrical stimulus was such that it would create a false-positive result. Each tooth was tested twice. 2. The ability of the digital pulp tester to make electrical contact and automatically start operation was evaluated under the following conditions: (a) on
*Tektronic
*Tektronix
501 power module, Tektronix,
Inc., Beaverton, Ore.
434 storage oscilloscope, Tektronix,
Inc.
Evaluation
Volume 58 Number 4
Table I. Effect of decreasing battery voltage on pulp tester output voltage Pulp tester outpui voltage (VOh)
15 20 30 40 50 60 70 80 90 100 110 120 130 140 150
_
6.3 volts* 14 20 29 33 36 38 40 46 54 57 62 65 72 80 80
4.8 volisf 10 18 27 32 34 38 39 40 50 55 58 62 68 75 80
439
Table II. Responseof endodontically treated teeth to digital pulp tester Tooth No.
Digital display reading at two battery voltages
of digital pulp tester
13 18 19 8 23 19 30 19
(
Response None None None None None None None Yes* Yest None None None None None None
1
Tooth No. 3 14 19 3 28 30 30 23 24 25 19 30 10 3 8
( Response None None None None None None None None None None None None None None None
*When retested, two negative responseswere obtained. I’When tooth was isolated with rubber dam on the mesial and distal, aspects,no responsewas elicited.
*Voltage dropped to 6.1 when the tester was operating. tVoltage dropped to 4.3 when the tester was operating.
ten vital teeth with no electrode media (electrolyte); (b) on ten porcelain facings; (c) with the operator wearing rubber gloves; and (d) with the operator using one hand. (Neither the hand holding the probe nor the other hand touched the patient.) 3. The sensation of the electrical stimulus was determined on four dentists under the following conditions: (a) with the probe applied to an anterior tooth; (b) with the probe applied to gingiva in an anterior region; and (c) with the vestibule filled with saline solution and the probe placed in the saline solution (but not touching tissue). RESULTS
The results from the laboratory portion of this study are as follows: 1. The “low battery” indicator was activated when the voltage dropped to 3.6 or 3.7 volts and was displayed as two flashing dots on the digital display (new battery voltage is usually 6 volts or more). 2. The “depleted battery” indicator was activated when the voltage dropped to 3.5 volts and was displayed as two continuous red dots and the number disappeared from the digital display. 3. The ability to stabilize outp,ut voltage with a drop in battery voltage is shown in Table I. When battery voltage dropped from 6.3 volts to 4.8 volts, stabilization was not complete but very close. The results from the clinical portion of this study are as follows: 1. When thirty nonvital, endodontically treated
teeth were tested, only two gave a positive response that could result in a false-positive determination (Table II). One of these gave a negative response when retested two additional times. The other gave a negative responsewhen isolated from adjacent teeth with strips of rubber dam. 2. The ability of the pulp tester to make electrical contact as indicated by the red light on the probe (Fig. 3) is shown in Table III. (a) When no electrode media was used on the tooth or probe, the pulp tester would not make electrical contact with any of the ten teeth and would not automatically start operation. (b) On the ten porcelain facings, the pulp tester would not make electrical contact or automatically start operation. (c) The digital pulp tester would not make electrical contact or begin operation when the operator was wearing gloves. (d) The pulp tester would not operate when the operator held the probe with one hand and did not touch the patient. However, placing the fingers of this hand on the patient’s lips established contact and the tester operated normally. 3. When the pulp tester was evaluated on four dentists, the following subjective responses were elicited: (a) On an anterior tooth, three dentists indicated that it created a sensation of vibration or tingling. The fourth felt a pulsating sensation along with a sensation of cold air.
440
Cooley, Stilley, and Lubow
Oral Surg. October, 1984
TaMs III. Lack of electrode media/porcelain facings:
Effect on ability of pup tester to make electrical contact
Type of test
Lack of electrode media (10 teeth tested) Porcelain facings (10 teeth tested)
Electrical contact established
None None
5. The digital display provides instant, easy readable information. Dieadvantages Fig. 3. Redlight (arrow)on the probehandleis activated
whenelectricalcontactis established.It flasheson and off when the maximum stimulus has beenreached.
(b) On anterior gingiva, two dentists indicated that it felt somewhat like a needle, with the sensation growing in intensity. Two others said that it was like little impulses (or pulsations) growing in intensity. (c) When vestibule was filled with saline solution, none of the four dentists felt any sensation with this procedure. DlSCUSSlON
The digital pulp tester was used by a group of ten dentists for 6 months. During this period of time, the following advantages and disadvantages were noted: Advantages
1. Intensity of the stimulus is such that patients find it more comfortable. When it was evaluated on four dentists, their impression was one of a tingling, vibrating, or pulsating sensation. 2. The red indicator light on the probe (Fig. 3) indicates when electrical contact is established with the tooth and then flashes on and off when the tester reaches maximum stimulus. 3. The unit will not turn on automatically and start the electrical stimulus until electrical contact is established with the tooth. This prevents jolting the patient, as might occur with a conventional, manually controlled pulp tester in those situations in which contact is not made until the tester has reached a higher voltage setting. 4. The unit turns on and off automatically when the probe is applied to the tooth. It is easy and quick to operate, as there are no buttons or controls that require manipulation for operation.
1. The probe tip is removable and easily falls out of the handle. Several attempts were made to adjust the probe tip so that it would be more secure in the handle, but without success. 2. Batteries may fall out of the battery holder, giving the impression that the unit is inoperable. There is a rubber pad designed to retain the batteries, but on two occasions they worked loose and the tester did not operate. 3. The speedcontrol setting for adjusting the rate of increase in the electrical stimulus does not have a label to indicate which direction is fast and which is slow. 4. The pulp tester will not operate if the dentist wears rubber gloves. 5. This pulp tester is considerably more expensive than others. The first three disadvantages are not great ones and could be corrected by the manufacturer. Most dentists do not wear gloves routinely, so this disadvantage is not a big obstacle. The price may be the biggest disadvantage; however, it is offset by the advantages of the unit. Matthews and Searle’ addressed the problem of false-positive results from nonvital teeth. In their review of the literature, they found two studies on this subject. Seltzer and associates*compared pulp tester data with histologic findings and found that five of eighteen nonvital teeth gave a positive response.In a similar study, Johnson and co-workers3 reported that fifteen of thirty-five nonvital teeth gave a positive response.When the digital pulp tester was applied to thirty nonvital, endodontically treated teeth, only two gave a positive response.This test was performed to determine the possibility of eliciting false-positive results. This could occur if the electrical stimulus is strong enough to stimulate the periodontium or if the electrical stimulus travels to adjacent teeth. In the caseof the maxillary right lateral
Evaluation of digital pulp tester 441 &&or, which gave a positive result, the stimulus apparently did travel to an adjacent tooth. When the lateral incisor was isolated from the adjacent teeth with narrow strips of rubber dam, there was no sensationwith the maximum stimulus. It appearsthat the possibility of creating a false-positive response(on a nonvital tooth) is small but doesexist. If there is any doubt, strips of rubber dam can be placed on the proximal surfacesand the test repeated. There is also one situation in which this device may give a flase-negative response(no responseon a vital tooth). This situation was noted during evaluation of the “low battery” and “depleted battery” indicators. When the battery voltage dropped to 4.0 volts (as measured with the pulp tester operating), the digital display continued to count upward, but the output voltage (measured with the oscilloscope) did not increase with the numbers on the digital display. In this situation, the operator would think that the pulp tester is operating normally, but the electrical stimulus would not be increasing. It could give the operator the impression that a tooth is nonvital when, in fact, it is vital. However, there was only one specific battery voltage at which this could occur, and it can be circumvented by replacing the batteries periodically. The necessity of an electrode medium has been addressed in several studies. Cooley and Robison4 evaluated toothpaste, water, and a commercial electrode gel and found little difference in the three, although toothpaste was the least effective. However, they also found that little voltage or current was passed to the tooth without an electrode medium. Martin, Ferris, and MazzellaS demonstrated a definite increase in the stimulus transmitted when an electrode medium is used. They also found that the type of medium is not significant but that it should have a water base. The digital pulp tester evaluated in this study would not automatically start operation without an electrode medium. It was placed on ten teeth without any electrolyte present and would not operate. It is interesting to note that when the pulp tester was applied to saline solution in the vestibule and allowed to reach maximum stimulus, no sensation was felt. This phenomenon was noted in another study’ with another brand of pulp tester. This probably occurs becausethe saline solution dispersesthe electrical stimulus over a wide area. For this reason, teeth should be completely dry during testing to prevent a false result. The evaluation of this digital pulp tester’s ability to stabilize output voltage as the battery voltage drops indicated that it did not provide complete
stabilization. When the battery voltage dropped from 6.3 volts to 4.8 volts, there were some minor variations in the output voltage. The voltage variations should not pose a problem. An electric pulp tester should be used only to determine vitality or nonvitality and not for diagnosis of pulp conditions. The clinician should not try to quantitate the response between teeth at any particular digital reading, as other variables may be present. The control for adjusting the rate of increase of the electrical stimulus did not have a label indicating which direction increased the speedand which direction decreasedthe speed.This originally causedsome patients to be jolted when the control was unknowingly set on “fast.” The rate of stimulus increase was so fast that the stimulus became uncomfortable before the probe could be removed from the tooth. However, this problem can be solved by adjusting the speed control before pulp testing is attempted. The operator can place his finger on the probe tip while holding the handle in the same hand. This will activate the pulp tester and the digital display. The speedcontrol can be adjusted at this time. Once the operator determines the speedthat is convenient and practical, a white mark can be placed on the control so that this position can be maintained. This digital pulp tester eliminates some of the variables associatedwith electric pulp testing, particularly those concerning establishment of electrical contact. Its simple operation allows the dentist to keep both hands steady and on the patient. It also permits constant observation of the patient for any signs of change. SUMMARY
A digital pulp tester was evaluated with a series of laboratory tests as well as with clinical usage. The ability of the pulp tester to operate automatically, increase the intensity of the stimulus automatically, stabilize output voltage, and indicate low or depleted batteries was evaluated. The pulp tester performed well in all these areas. Clinically, it was found to perform consistently, dependably, accurately, and easily for all dentists who evaluated its use. The only notable problem was the inability to use this unit while wearing surgical gloves. All in all, the digital pulp tester could be a most valuable addition to the dental armamentarium. REFERENCES
1. Matthews B, Sea& B: Some observations on pulp testers. Br Dent J 137: 307, 1974. 2. Seltzer S, Bender IB, Ziontz M: The dynamics of pulp inflammation: correlations between diagnostic data and actual histologic findings in the pulp. ORAL SURG 16: 846, 1963.
442 Cooley, Stilley, and Lubow 3. Johnson RH, Dachi S, Haley J: Pulpal hyperemia-a correlation of clinical and histologic data from 706 teeth. J Am Dent Assoc 81: 108, 1970. 4. Cooley RL, Robison SF: Variables associated with electric pulp testing. ORAL SURG 50; 66, 1980. 5. Martin H, Ferris C, Mazzella W: An evaluation of media used in electric pulp testing. ORAL SURG 27: 374, 1969.
Oral Surg. October, 1984 Reprint requesls 10:
Dr. Robert L. Cooley USAF SAM/NGD Brooks AFB, TX 78235