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Comparative cleansing efficiency of manual and power brushing
Com parative cleansing efficiency of m anual and power brushing
Gertrude A. Q u ig le y * and John W. Hein,\ D .M .D ., P h.D ., Boston
In an experiment with 50 persons from the Tu fts University M edical Center, a reciprocating m otion electric toothbrush was as effective at rem oval of massive accumulations of dental plaque as a two row, medium hard, nylon bristle tooth brush, and was superior to an arcuate m otion electric toothbrush. Subjects spent m ore time brushing with the reciprocat ing motion electric toothbrush, perhaps because of ease of use and m ore pleasur able sensations.
cannot be disregarded. For example, if the use of a power device encouraged the subject to brush longer than he ordinarily did with a hand brush and this factor alone resulted in an improved state of oral hygiene, the application of power to the toothbrush would be justified. Since early studies with the electric device re vealed that important pleasurable fea tures were associated with its use, the criterion of thoroughness of cleaning in dependent of time was adopted as the main measure of cleaning efficiency. M ETHODS
The purpose of the studies described in this report was to evaluate the efficiency of a reciprocating motion toothbrush as an instrument for cleaning the teeth. These studies were initiated during the early stages of the development of the device; therefore, they reflect both pro gressive engineering improvements and the accumulation of information showing that the danger of hard tissue abrasion and soft tissue laceration was not an im portant consideration with this device. The two main criteria that could be used to judge efficiency were speed of cleaning and thoroughness of cleaning. From a practical standpoint, however, speed per se is not a reliable measure of efficiency because the factor of pleasure
The subjects employed in these experi ments were personnel of the Tufts Uni versity Medical Center including a pre dominance of freshmen and sophomores in the dental school. Fifty subjects were enlisted for the studies, and all data were obtained from experiments performed with representatives from this group. Cleansing efficiency was determined by recording the removal of dental plaques which had been stained with a 20 milli liter, 30 second mouthwash containing .075 per cent basic fuchsin. This staining procedure was followed by two rinses of water. Before each brushing experiment, the subjects refrained from use of a tooth brush for three days in order to permit dental plaque to accumulate.
).
QUIGLEY—HEIN . . . VOLUME 65, JULY 1962 • 41/27
0 - no plaque 1 - flecks of stain at gingival margin 2 - definite line of plaque at gingival margin 3 - gingival third of surface 4 - two thirds of surface 5 - greater than two thirds of surface Fig. I • Plaque scoring system
Kodachrome photographs o f the labial surfaces o f the anterior teeth were taken before and after brushing during certain o f the experiments. These photographs serve as a record o f the dental plaqueform ing tendency o f the individual sub jects as w ell as a record o f cleansing ability o f the various brushes. In all studies a clinical recording o f the stained plaque was made before and after brushing. T h e examiner made a quanti tative estimate o f the amount o f plaque present on the buccal, labial and lingual surfaces o f the teeth as shown in Figure 1. T h e same examiner conducted the ex aminations in all experiments. T h e statis tics in the tables are based on these den tal plaque scores. A summary o f the procedure employed in most o f the studies was as follow s: 1. Cessation o f toothbrushing for three days before each brushing experiment. 2. A ll subjects reporting to the lab oratory on the same day. 3. M outh rinses to stain plaques fol lowed by two water rinses. 4.
Charting o f stained plaques.
5. Photographs o f stained plaques on labial surfaces.
6. Experimental brushing plus timing of brushing. 7. Charting o f stained maining after brushing.
8. Photographs of stained plaques re maining on labial surfaces after brushing. Evaluation o f the data consisted o f sta tistical analysis based on the average amount of plaque per tooth surface per person. E XP E R IM E N TA L R E S U LTS
A t the outset it was necessary to select a common type o f nonmechanical tooth brush to serve as a control. Am ong the most widely used designs are the two row, rectangular head brushes suggested in the literature distributed by the Bureau of Dental Health Education o f the Am eri can Dental Association and multi-tufted, fine bristle, rectangular head brushes. T h e results o f an experiment with 44 sub jects to determine the relative cleaning efficiency o f these two designs is shown in Table 1. A comparison o f the plaque scores before and after brushing shows that under the conditions o f these experi ments both designs were equally efficient. W ith this evidence in hand, the two row, medium hard, rectangular head, nylon bristle brush was selected as the control brush for our studies. T h e initial experiments with the recip rocating device were conducted with fine bristles of .007 inch diameter, but as data accumulated from hard and soft tissue toxicity studies, larger diameter bristles were tested. T h e results are shown in
Tab le 1 • Selection o f co ntrol brush A v e r a g e plaque sco re per tooth surface Type of brush
N o . of subjects
Labial Before
After
plaques re
Buccal Before
After
Com bined Before
After
T w o row
44
2.98
0.30
3.32
0.66
3.17
0.50
Multi-fine
44
3.04
0.28
3.31
0.65
3.19
0.49
42/23 • THE JOURNAL OF THE AMERICAN DENTAL ASSOCIATION
Tab le 2 • Effect o f bristle diam eter A v e ra g e plaque sc o re p er to o th *
Bristle diam eter
N o . of subjects
0.007"
44
3.14
0.89 ± 0.46
0.009"
36
3.35
0.22 + 0.20N.
0.012"
36
3.29
/t 0.14 ± 0 .1 4 '
A fter
Before
*Buccal + labial. ■¡Critical ratio = 1.95. Critical ratio is a measure of the statistical significance of the difference between the means. A value of 2.0 or more indicates a 95 per cent or better chance that the difference between the means is not due to chance. (Garrett, H. E. Statistics in psychology and education, ed. 4. New York, Longmans, Green & Co., Inc., 1953, p. 215.)
T a b le 2. It can be seen that the larger diameter bristles were more efficient under the experimental conditions o f our tests. T h e difference between the .009 inch and .012 inch bristle diameters was o f borderline significance. A comparison between the reciprocat ing motion electric device equipped with
a .012 inch bristle and the hand brush is shown in Table 3. Both devices gave comparable results in their ability to re move massive accumulations o f dental plaques from tooth surfaces. Another type o f motion possible with electromechanical toothbrushes is the arc. Table 4 presents the results o f an experi ment in which the hand brush, an electric reciprocating motion brush and an elec tric arcuate motion brush were tested. It is obvious from these data that, under the conditions o f the experiment, a mechan ical arc motion was not as efficient in removing plaque as the mechanical re ciprocating motion or hand brushing. Again, no statistically significant differ ence was found between the reciprocating motion device and the hand brush. H o w ever, as can be seen, the arc motion device was significantly different from the other two devices. One interesting observation that arose from these studies was the relatively long
T a b le 3 • C om p ariso n of hand brushing with m echanical brushing A v e r a g e plaque score per tooth surface T yp e o f brush
N o . of subjects*
Electric
36
3.39
36
0.16 ± 0 . 1 4 \
/t
3.29
After
Before
After
Before T w o ro w hand
lingual
Buccal-labial
0.14 ± 0 .1 4 '
2.88
0.74 ± 0.56>
2.91
0.66 + 0.58'
*DentaI students. f N o statistically significant difference.
T a b le 4
• C om p ariso n of hand brushing with reciprocating and a rc m otion electric devices A v e ra g e plaque sco re per tooth surface
T ype of brush
N o . of subjects
Buccal-labial
Lingual
Before
After 0.25 ± 0.26 V NA 0.33 ± 0.30
T w o row hand
34
3.14
0.012tf reciprocating electric
34
3.11
A rc electric
34
Before
After
2.92
2.90 0.92± 0.59v N C 0.95 ± 0.66,
2.93
1.36
/\ 3A7
Critical ratios: A-3.23, B-2.22, C-2.6?, D-2.39.
0.53 ± 0.43
¡/
QUIGLEY— HEIN
time the subjects employed the electric driven reciprocating brush. Although all subjects in these studies were instructed to brush all tooth surfaces carefully and since they were predominantly dental stu dents they followed these directions dili gently, the average brushing time still was considerably longer with the reciprocat ing motion electric brush. For example, in the experiments described in the tables, the groups using the reciprocating elec tric toothbrush averaged from 0.3 to 0.9 minutes longer brushing times than the average o f the hand toothbrush groups. In the experiment for which data are given in Table 4, the average brushing times for the groups using the hand, re ciprocating electric and arcuate electric brush were 2.3, 2.8 and 2.3 minutes re spectively. Ease o f use and perhaps m ore pleasurable sensations during use m ay account for the longer brushing times associated with the use o f the reciprocat ing electric toothbrush. H owever, it is important to note that within the range
. VOLUME 65, JULY 1962 • 43/29
o f brushing times encountered in these experiments, no correlation could be found between duration of brushing and amount o f dental plaque removed. SUM M ARY
Under the conditions o f these experi ments which include oral hygiene-con scious subjects, long brushing times and massive accumulations o f dental plaque, the reciprocating motion electric tooth brush was as effective at removal of dental plaque as a two row, medium hard, nylon bristle toothbrush and supe rior to an arcuate motion electric tooth brush. 136 Harrison Avenue
Presented as a clinical lecture, one-hundred and second annual session, American Dental Association, Philadel phia, October 16, 1961. A id ed by a grant from the General Electric Company, dental ^health section, Ashland, Mass. ‘ Special research assistant to the dean, Tufts Univer sity School of Dental Medicine. fDean and professor of preventive dentistry, Tufts Uni versity School of Dental Medicine.
Specialized Communication • Each scientific discipline has cultivated a special concern for its highly selective focus on the universe w ith its patterned perception of those messages, dimen sions, or operations of the world for w hich it has a special competence. Each of these scientific groups also has developed its own symbol system, its verbal and nonverbal symbols for inter group communication and for thinking and reflecting and reporting its studies and experimenta tions, as in mathematics and symbolic logic. Each profession and each specialized occupational group has its own, often highly specialized, conceptual framework for w hat it believes, assumes, and takes for granted, its specific ways of thinking, observing, m easuring, judging and evaluating situations, events, organisms, persons and their behavior. Each operates with its own conception of hum an nature and assumptions about hum an conduct. Each profession has also developed its own specialized vocabulary and language for intraprofessional com m unication, frequently relying upon abbreviations, esoteric signs and symbols that are fam iliar only to members of that profession. Lawrence K . Frank. Interprofessional Communication. A m . ] . Pub. Health 51:1798 Dec. 1961.
Gertrude A. Q u ig le y * and John W. Hein,\ D .M .D ., P h.D ., Boston
In an experiment with 50 persons from the Tu fts University M edical Center, a reciprocating m otion electric toothbrush was as effective at rem oval of massive accumulations of dental plaque as a two row, medium hard, nylon bristle tooth brush, and was superior to an arcuate m otion electric toothbrush. Subjects spent m ore time brushing with the reciprocat ing motion electric toothbrush, perhaps because of ease of use and m ore pleasur able sensations.
cannot be disregarded. For example, if the use of a power device encouraged the subject to brush longer than he ordinarily did with a hand brush and this factor alone resulted in an improved state of oral hygiene, the application of power to the toothbrush would be justified. Since early studies with the electric device re vealed that important pleasurable fea tures were associated with its use, the criterion of thoroughness of cleaning in dependent of time was adopted as the main measure of cleaning efficiency. M ETHODS
The purpose of the studies described in this report was to evaluate the efficiency of a reciprocating motion toothbrush as an instrument for cleaning the teeth. These studies were initiated during the early stages of the development of the device; therefore, they reflect both pro gressive engineering improvements and the accumulation of information showing that the danger of hard tissue abrasion and soft tissue laceration was not an im portant consideration with this device. The two main criteria that could be used to judge efficiency were speed of cleaning and thoroughness of cleaning. From a practical standpoint, however, speed per se is not a reliable measure of efficiency because the factor of pleasure
The subjects employed in these experi ments were personnel of the Tufts Uni versity Medical Center including a pre dominance of freshmen and sophomores in the dental school. Fifty subjects were enlisted for the studies, and all data were obtained from experiments performed with representatives from this group. Cleansing efficiency was determined by recording the removal of dental plaques which had been stained with a 20 milli liter, 30 second mouthwash containing .075 per cent basic fuchsin. This staining procedure was followed by two rinses of water. Before each brushing experiment, the subjects refrained from use of a tooth brush for three days in order to permit dental plaque to accumulate.
).
QUIGLEY—HEIN . . . VOLUME 65, JULY 1962 • 41/27
0 - no plaque 1 - flecks of stain at gingival margin 2 - definite line of plaque at gingival margin 3 - gingival third of surface 4 - two thirds of surface 5 - greater than two thirds of surface Fig. I • Plaque scoring system
Kodachrome photographs o f the labial surfaces o f the anterior teeth were taken before and after brushing during certain o f the experiments. These photographs serve as a record o f the dental plaqueform ing tendency o f the individual sub jects as w ell as a record o f cleansing ability o f the various brushes. In all studies a clinical recording o f the stained plaque was made before and after brushing. T h e examiner made a quanti tative estimate o f the amount o f plaque present on the buccal, labial and lingual surfaces o f the teeth as shown in Figure 1. T h e same examiner conducted the ex aminations in all experiments. T h e statis tics in the tables are based on these den tal plaque scores. A summary o f the procedure employed in most o f the studies was as follow s: 1. Cessation o f toothbrushing for three days before each brushing experiment. 2. A ll subjects reporting to the lab oratory on the same day. 3. M outh rinses to stain plaques fol lowed by two water rinses. 4.
Charting o f stained plaques.
5. Photographs o f stained plaques on labial surfaces.
6. Experimental brushing plus timing of brushing. 7. Charting o f stained maining after brushing.
8. Photographs of stained plaques re maining on labial surfaces after brushing. Evaluation o f the data consisted o f sta tistical analysis based on the average amount of plaque per tooth surface per person. E XP E R IM E N TA L R E S U LTS
A t the outset it was necessary to select a common type o f nonmechanical tooth brush to serve as a control. Am ong the most widely used designs are the two row, rectangular head brushes suggested in the literature distributed by the Bureau of Dental Health Education o f the Am eri can Dental Association and multi-tufted, fine bristle, rectangular head brushes. T h e results o f an experiment with 44 sub jects to determine the relative cleaning efficiency o f these two designs is shown in Table 1. A comparison o f the plaque scores before and after brushing shows that under the conditions o f these experi ments both designs were equally efficient. W ith this evidence in hand, the two row, medium hard, rectangular head, nylon bristle brush was selected as the control brush for our studies. T h e initial experiments with the recip rocating device were conducted with fine bristles of .007 inch diameter, but as data accumulated from hard and soft tissue toxicity studies, larger diameter bristles were tested. T h e results are shown in
Tab le 1 • Selection o f co ntrol brush A v e r a g e plaque sco re per tooth surface Type of brush
N o . of subjects
Labial Before
After
plaques re
Buccal Before
After
Com bined Before
After
T w o row
44
2.98
0.30
3.32
0.66
3.17
0.50
Multi-fine
44
3.04
0.28
3.31
0.65
3.19
0.49
42/23 • THE JOURNAL OF THE AMERICAN DENTAL ASSOCIATION
Tab le 2 • Effect o f bristle diam eter A v e ra g e plaque sc o re p er to o th *
Bristle diam eter
N o . of subjects
0.007"
44
3.14
0.89 ± 0.46
0.009"
36
3.35
0.22 + 0.20N.
0.012"
36
3.29
/t 0.14 ± 0 .1 4 '
A fter
Before
*Buccal + labial. ■¡Critical ratio = 1.95. Critical ratio is a measure of the statistical significance of the difference between the means. A value of 2.0 or more indicates a 95 per cent or better chance that the difference between the means is not due to chance. (Garrett, H. E. Statistics in psychology and education, ed. 4. New York, Longmans, Green & Co., Inc., 1953, p. 215.)
T a b le 2. It can be seen that the larger diameter bristles were more efficient under the experimental conditions o f our tests. T h e difference between the .009 inch and .012 inch bristle diameters was o f borderline significance. A comparison between the reciprocat ing motion electric device equipped with
a .012 inch bristle and the hand brush is shown in Table 3. Both devices gave comparable results in their ability to re move massive accumulations o f dental plaques from tooth surfaces. Another type o f motion possible with electromechanical toothbrushes is the arc. Table 4 presents the results o f an experi ment in which the hand brush, an electric reciprocating motion brush and an elec tric arcuate motion brush were tested. It is obvious from these data that, under the conditions o f the experiment, a mechan ical arc motion was not as efficient in removing plaque as the mechanical re ciprocating motion or hand brushing. Again, no statistically significant differ ence was found between the reciprocating motion device and the hand brush. H o w ever, as can be seen, the arc motion device was significantly different from the other two devices. One interesting observation that arose from these studies was the relatively long
T a b le 3 • C om p ariso n of hand brushing with m echanical brushing A v e r a g e plaque score per tooth surface T yp e o f brush
N o . of subjects*
Electric
36
3.39
36
0.16 ± 0 . 1 4 \
/t
3.29
After
Before
After
Before T w o ro w hand
lingual
Buccal-labial
0.14 ± 0 .1 4 '
2.88
0.74 ± 0.56>
2.91
0.66 + 0.58'
*DentaI students. f N o statistically significant difference.
T a b le 4
• C om p ariso n of hand brushing with reciprocating and a rc m otion electric devices A v e ra g e plaque sco re per tooth surface
T ype of brush
N o . of subjects
Buccal-labial
Lingual
Before
After 0.25 ± 0.26 V NA 0.33 ± 0.30
T w o row hand
34
3.14
0.012tf reciprocating electric
34
3.11
A rc electric
34
Before
After
2.92
2.90 0.92± 0.59v N C 0.95 ± 0.66,
2.93
1.36
/\ 3A7
Critical ratios: A-3.23, B-2.22, C-2.6?, D-2.39.
0.53 ± 0.43
¡/
QUIGLEY— HEIN
time the subjects employed the electric driven reciprocating brush. Although all subjects in these studies were instructed to brush all tooth surfaces carefully and since they were predominantly dental stu dents they followed these directions dili gently, the average brushing time still was considerably longer with the reciprocat ing motion electric brush. For example, in the experiments described in the tables, the groups using the reciprocating elec tric toothbrush averaged from 0.3 to 0.9 minutes longer brushing times than the average o f the hand toothbrush groups. In the experiment for which data are given in Table 4, the average brushing times for the groups using the hand, re ciprocating electric and arcuate electric brush were 2.3, 2.8 and 2.3 minutes re spectively. Ease o f use and perhaps m ore pleasurable sensations during use m ay account for the longer brushing times associated with the use o f the reciprocat ing electric toothbrush. H owever, it is important to note that within the range
. VOLUME 65, JULY 1962 • 43/29
o f brushing times encountered in these experiments, no correlation could be found between duration of brushing and amount o f dental plaque removed. SUM M ARY
Under the conditions o f these experi ments which include oral hygiene-con scious subjects, long brushing times and massive accumulations o f dental plaque, the reciprocating motion electric tooth brush was as effective at removal of dental plaque as a two row, medium hard, nylon bristle toothbrush and supe rior to an arcuate motion electric tooth brush. 136 Harrison Avenue
Presented as a clinical lecture, one-hundred and second annual session, American Dental Association, Philadel phia, October 16, 1961. A id ed by a grant from the General Electric Company, dental ^health section, Ashland, Mass. ‘ Special research assistant to the dean, Tufts Univer sity School of Dental Medicine. fDean and professor of preventive dentistry, Tufts Uni versity School of Dental Medicine.
Specialized Communication • Each scientific discipline has cultivated a special concern for its highly selective focus on the universe w ith its patterned perception of those messages, dimen sions, or operations of the world for w hich it has a special competence. Each of these scientific groups also has developed its own symbol system, its verbal and nonverbal symbols for inter group communication and for thinking and reflecting and reporting its studies and experimenta tions, as in mathematics and symbolic logic. Each profession and each specialized occupational group has its own, often highly specialized, conceptual framework for w hat it believes, assumes, and takes for granted, its specific ways of thinking, observing, m easuring, judging and evaluating situations, events, organisms, persons and their behavior. Each operates with its own conception of hum an nature and assumptions about hum an conduct. Each profession has also developed its own specialized vocabulary and language for intraprofessional com m unication, frequently relying upon abbreviations, esoteric signs and symbols that are fam iliar only to members of that profession. Lawrence K . Frank. Interprofessional Communication. A m . ] . Pub. Health 51:1798 Dec. 1961.