Clinical Research Associates
Test Method for Patient Toleration
of Tooth Irradiation by Curing Lights
During Vital Tooth Bleaching
July 21, 2000
Clinical Science Department
Clinical Research Associates
| I. | Purpose of Test |
| II. | Materials |
| III. | Equipment Preparation |
| IV. | Test Procedure |
| V. | Analysis of Data |
I. Purpose of Test
Many vital tooth bleaching products are used in conjunction with high intensity curing lights. The light heats the bleach & the tooth, which is thought to accelerate or facilitate the bleaching process. The purpose of this test is to determine how long a person will tolerate a curing light illuminating a bleach product before they experience an uncomfortable sensation, & to measure the temperature of the bleach during the procedure.
II. Materials
| bleach product(s) | 250 ml beaker |
| curing light(s) | 5 x 12 x 6 inch plastic basin |
| digital timer | crushed ice |
| Tegam 871A digital thermometer | calculator |
| Omega TT-K-30-50 FT thermocouple wire | paper towels |
| Omega type K subminiature connector | blindfold |
| Omega type K coiled extension cable | Lysol disinfectant spray |
| Unitek orthodontic bracket welder | orange protective glasses |
| wire cutters | cotton tipped applicators |
| wire strippers | masking tape |
| razor blade or scalpel | marking pen |
| scissors | ruler |
| jeweler’s screw driver set | dental chair with accessories |
| 53/4 inch glass transfer pipet | explorer |
| automix impression material with gun & tip | resin instrument |
| banana plugs | 2 x 2 gauze |
| 1 MW resistor | 4 x 4 gauze |
| soldering iron | cheek retractor |
| rosin core solder | gloves |
| masks | patient bibs |
| computer | jeweler’s file |
|
GMH Engineering Data Brick data acquisition system with host computer software & accessories |
III. Equipment Preparation
A. Data Acquisition System
1. Connection Cable
a. Select a 5 wire sensor cable for channel 1 of the Data Brick.
b. Strip the cable for 2 inches & cut back the wire braid & metal foil shield.
c. Strip the green, white, & black wires for 1/4 inch.
d. Solder a 1 MW resistor between the white & black wires.
e. Connect banana plugs to the green & white wires.
f. Fold back the unused wires & tape them to the cable, out of the way.
2. Software Setup
a. The computer should be capable of operating in DOS & have an available COM port.
b. Create a directory called thebrick on the hard drive.
c. Within DOS, go to the thebrick directory, insert the floppy disk containing the Data Brick software, & type "a:\install" to install the program.
d. Within DOS, switch to the thebrick directory, & type "brick" to launch program.
e. Under Setup, set the following parameters to the indicated values:
Display: Color
Printer Type: (whatever you have connected)
Resolution: 90 x 90
Print Text As: Graphics
Brick Port: Com 1
Brick Baud: 57600
Printer Port: LPT1
Port Access: Direct
Backups: Keep
f. Under Brick, select Test Setup.
g. Create a new test file by typing in the file name "bleach_t", then selecting OK, then select Create New.
h. On the screen labeled Test Setup For: BLEACH_T.TST, type in the serial number of the Data Brick, & its name. Then select Edit to go to the Brick Setup screen.
i. Make sure that the Chn 1 Stat is selected to On.
j. Select the "1" under Chn to edit the channel 1 parameters to the following values:
Select Sensor: Default Analog Sensor
Serial Number: (blank)
Calibration Constant: (may be any number, depending on calibration)
Sensor Output Offset: 0 degrees C/volt
Sensor Output + & - Full Scale: 0 degrees C
Name: gel temp
Units: degrees C
Sample Rate: S1
Gain: 10
Channel Offset: Auto
Rest Offset: 0 Volts
Rest Value: 0 degrees C
Channel Range + Full Scale: (some value depending on calibration)
Channel Range - Full Scale: (some value depending on calibration)
Minimum Resolution: (some value depending on calibration)
k. Select OK to return to the Brick Setup screen.
l. Set the following parameters to the indicated values:
Data Acquisition Mode: Low Speed
Trigger Mode: Single Event
Trigger Type: Open=Triggered
Primary Sample Rate (P): 100 Samples/Second
Secondary 1 Sample Rate (S1): 10 Samples/Second
Secondary 2 Sample Rate (S2): 2 Samples/Second
Low Pass (Anti-Aliasing) Filter Corner Frequency: 1 Hz
Transducer Excitation: Off
Chn: 1 On, Rate: S1, Name: gel temp, Units: degrees C
(channels 2 - 8 are Off; counters A1 - B2 are Off)
Fill Memory: not selected
Maximum Trigger Events: ( 1- 1): 0
Data Set Size: 1 Samples
Memory Usage: 0.7%
Test Duration: 1800 Data Sets, 180 Seconds
Pre-Trigger: 0 Data Sets, 0 Seconds
m. Select Done to exit the Brick Setup screen & automatically save the setup.
n. On subsequent uses of this test method, it is necessary only to choose the "bleach_t.tst" test file to recall all these parameters.
B. Thermometer
1. Thermocouple
a. Cut a 24 inch length of thermocouple wire.
b. Separate one end for 1/2 inch & cut away the clear outer sheath with scissors.
c. Strip the separated ends for 1/4 inch.
d. Open the subminiature connector with a jeweler’s screwdriver.
e. Connect the stripped ends under the screw terminals: yellow wire to +, brown wire to -.
f. Close the connector, making sure the wires are not pinched & no bare wires are exposed.
g. Strip, but do not separate the other end for 1/16 inch. Use a razor blade to carefully remove the clear outer sheathing & the yellow & brown insulation without damaging the wires.
h. Position the two exposed wires between the electrodes of the spot welder.
i. Activate the spot welder to join the wires. Repeated attempts may be necessary. The goal is to get as small a joint as possible.
Figure 1: Close up view of welded thermocouple.
j. File down the tip as necessary to remove any sharp edges.
2. Thermal Probe
a. Fill the pipet with impression material.
b. Immediately insert the thermocouple into the large end of the pipet & push it until it extends out the narrow end 1/16 inch.
c. Allow impression material to set.
d. Clean any impression material from the actual thermocouple junction.
Figure 2: Finished thermal probe.
3. Calibration
a. Connect thermal probe.
i. Connect the thermal probe to the thermometer TC1 jack.
ii. Set thermometer to ° C & TC1.
iii. Turn on thermometer.
b. Prepare ice water bath.
i. Place beaker into plastic basin.
ii. Fill beaker & basin with crushed ice.
iii. Fill beaker with cold water, partially fill basin with water.
iv. Allow system to come to equilibrium at 0° C, approximately 10 minutes.
v. Insert thermal probe into beaker. Thermometer should read 00.0° C.
Figure 3: Ice bath at 0.0° C.
c. Connect Data Brick.
i. Connect sensor cable to output jacks of thermometer: white wire to +mV output, green wire to -mV output.
ii. Plug in Data Brick.
iii. Plug I/O serial cable of Data Brick into COM1 port on computer.
iv. Launch the Brick software.
v. Under Brick select Test Setup.
vi. Select bleach_t.tst test file & press OK.
vii. Select Edit.
viii. Select Chn 1.
ix. Set Calibration Constant to: 1 degrees C/volt, & press OK.
x. Select Done, Done.
xi. Select Brick, Brick.
xii. Select Calibrate, Clear Auto Offset, wait for it to clear, then select Done.
xiii. Select Acquire Data, Now, wait for it to clear memory, then press OK.
d. Make temperature measurements.
i. Press trigger to begin data collection (green light should extinguish).
ii. Wait approximately 30 seconds with probe in water bath at 0.0° C.
iii. Remove probe to another temperature (example: ~ 36° C under tongue), & wait 30 seconds after it has stabilized, & record temperature.
iv. Remove probe to a third temperature (example: room temperature at ~ 20° C or warm water bath at ~ 60° C), & wait 30 seconds after it has stabilized, & record temperature.
v. Put probe back into 0.0° C water bath for remainder of time.
vi. When yellow light on Data Brick turns on, the data acquisition is complete.
vii. Select Upload Data, & type in a filename & press OK. Then enter any comments (such as the sequence of temperatures) & select OK.
viii. Select Post Process Data & select the filename just created, then press OK.
ix. Select Done.
x. Select Brick, ASCII Export.
xi. Select the filename of the calibration file, select Speadsheet import (*.CSV), & press Export. This will create an ASCII file of the data with the CSV extension.
xii. Exit the Brick software.
e. Calculate calibration constant.
i. Start MicroSoft Excel.
ii. Import the calibration file (with .csv extension).
iii. Calculate the average value for each of the stable temperature regions. It may help to graph the data to visualize the stable temperature regions.
Example: initial 0.0° C ice water = 0.00147 volts
body temp of 36.0° C = 0.03629 volts
warm bath at 57.3° C = 0.05758 volts
final 0.0° C ice water = 0.00033 volts
iv. Calculate the calibration constant for the elevated temperatures by dividing the temperature by the voltage.
Example: 36.0° C / 0.03629 volts = 992.0088
57.3° C / 0.05758 volts = 995.1372
v. Verify that the calibration constants are similar, then average them.
Example: 993.573
vi. Return to the Brick software & enter this calibration constant into the Channel 1 Setup.
f. Verify calibration.
i. Repeat the calibration test with the new calibration constant (sections 3.C.xi. - 3.D.ix).
ii. Select Plot, select the filename, & press OK, OK.
iii. Select Config, Cursor, Ok, to turn on the green cursor line.
iv. Click & drag the cursor over the graph. Verify that the stable temperature regions at the various temperatures match the temperature readout recorded from the thermometer itself.
C. Curing Light
1. Review the bleach instructions to find the recommended distance that the light is to be held from the tooth (1/4 inch or 6 mm is typical).
2. Using the ruler, make a mark on the handle of a cotton tipped applicator at the specified distance from the end.
3. Cut the handle about 3/8 inch beyond the mark.
4. Tape the cut piece to the light guide with the mark flush to the end, it then becomes a spacer which will maintain the light at the correct distance from the tooth.
Figure 4: Light guide with spacer in place.
D. Record Form
1. Prepare a record form with spaces for the following information to be recorded:
date
patient
bleach product
curing light
distance between light & tooth
bleach thickness
recommended light irradiation time, with number of passes & applications
maximum time tolerated
maximum temperature reached
patient comments about sensation & temperature of tooth (felt by tip of tongue)
tooth number treated
Intensity of curing light(s)
filename where temperature information is stored
E. Dental Chair & Operatory
1. Set up the operatory ready to seat a patient, include at least the following items:
infection control barriers
air / water syringe tips
suction hose tips
2. Place the following items within easy reach of the operators:
2 x 2 gauze
4 x 4 gauze
resin instrument for handling bleach
explorer for handling bleach
orange safety glasses
masks & gloves
patient bibs
blindfold for patient
thermal probe connected to data acquisition system
3. Place the curing light(s) nearby so that they can reach the patient.
4. Place the bleach product(s) nearby.
F. Bleach
1. Mix each bleach according to the manufacturer’s directions just prior to beginning test.
2. If a bleach specifies mixing immediately before application to teeth, then do not mix it until ready to apply.
IV. Test Procedure
A. Seat Patient
1. Have patient sit in dental chair.
2. Explain to patient that the test will not cause sudden pain. Instead they should be aware of what sensation the tooth feels. When that sensation becomes something they feel is painful, then they should alert the operator to remove the light.
3. Tell the patient to immediately feel the lingual of the tooth with the tip of the tongue when the light is removed so that they can describe how warm it feels.
4. Place a patient bib.
5. Recline the patient.
6. Place the blindfold over the patient’s eyes so thay cannot see either the type of bleach or light being used.
7. Place the cheek retractor to keep lips away from bleach on tooth surfaces.
B. Prepare for Treatment
1. Select a tooth to treat from the following list of smaller, anterior teeth: 7, 10, 22, 23, 24, 25, 26, 27.
2. Turn on thermometer, Data Brick, & computer.
3. Launch Brick software & load the bleach_t.tst test file.
4. Prepare the data acquisition system by selecting Acquire Data Now, OK, so it is only waiting for the trigger signal.
C. Perform Bleach Procedure
1. Apply a small amount of bleach to the facial surface of the tooth. Take care to insure it will not touch the soft tissue around the tooth.
2. Insert the thermal probe into the bleach, against the tooth. Wait a few seconds for it to stabilize.
3. Press the trigger of the Data Brick to begin data acquisition. Wait a few seconds to get the baseline temperature recorded prior to activating light.
4. Position curing light directly over bleach, held off at the correct distance by the spacer.
5. Activate curing light.
6. Keep track of elapsed time with digital timer or using audible signals from the light.
7. If the patient indicates to cease, remove the light & turn it off. Immediately record the length of time tolerated.
8. If the patient does not indicate to cease, turn the light off after 120 seconds of exposure.
9. Leave the thermocouple in the bleach at least 20 more seconds to record the cool down period.
10. Remove the thermal probe & rinse it clean with air / water spray.
11. Remove bleach with instruments.
12. Wipe excess bleach away with 2 x 2 gauze.
13. Remove patient’s blindfold.
14. Help patient sit up & rinse trace of bleach from mouth with water.
D. Record Data
1. Record patient’s observations about sensation & temperature of the tooth.
2. Make sure all the fields on the record sheet are properly filled in, especially the toleration time & maximum temperature.
3. Wait for yellow light to turn on, indicating end of data acquisition.
4. Select Upload Data.
5. Type in a filename for this patient & light / bleach treatment. Press OK.
6. Enter comments- usually the light & bleach used, press OK.
7. Select Post Process Data. Select the filename & press OK.
E. Multiple Measurements
1. To test another bleach / light combination, move to a non-adjacent tooth to avoid sensation overlap, or treat the patient again on another day.
2. Repeat the test (A.5. - D.7. above).
3. Several different people should be tested with the same products due to differences in sensitivity among people.
F. Cleaning Instruments
1. Between patients, all instrument should be properly disinfected with Lysol, or sterilized where possible.
2. Change all barriers & accessories on the chair.
V. Analysis of Data
A. Determine Maximum Temperature (& Toleration Time)
1. Plot each file in the Brick software.
2. Use the cursor to find the maximum temperature. For teeth in which sensitivity caused the light to be removed, the peak should be a well defined point just prior to a precipitous drop in temperature. If the light never had to be removed, the peak will be a much broader curve, perhaps even flat.
3. Record the maximum temperature.
4. Make sure the length of time tolerated is properly recorded. If it was missed during the procedure it can be recovered from the graphs. Where the temperature first rises sharply is when the light was activated. Where the temperature drops precipitously is when it was deactivated.
B. Expression of Results
1. Make a table showing each unique treatment tested (bleach / light combination).
2. Next to each treatment, show the toleration times & maximum temperatures for each patient treated.
3. Include on the table any variables that may have significant influence on the toleration time (for example: tooth number & light intensity).
4. Order the data (toleration times) by each of the other variables to look for patterns in the data.
5. Perform a statistical analysis to determine which treatments are statistically different.
CRA Home | What is CRA? | The CRA Newsletter | Update Courses | Contact CRA
All Content
Copyright 
Clinical Research Associates.