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Periodontal disease in the rice rat
Periodontia PERIODONTAL IV.
The Effects
OM P.
GUPTA,
of Antibiotics
DISEASE
IN THE RICE RAT
on the Incidence
of Periodontal
B.D.S., M.S.,* AINA M. AUSKAPS, D.M.D., SHAW, PH.D., BOSTON, MASS.
AND
Lesions
JAMES
H.
ELATIVELY few studies have been reported on the effects of antibiotic administration on the manifestations of periodontal disease in human beings. Strockl was among the first to report on the beneficial influence of penicillin upon the gingival tissues. He observed 198 male patients who had received total penicillin dosages of 80,000 to 9,000,OOOunits in the treatment of various infections, including syphilis, gonorrhea, osteomyelitis, septicemia, etc. He stated that a marked improvement was observed in the condition of the gingival tissues, with better tissue tone, less tendency to bleed, and a remarkable ability to heal. These improvements occurred even in the presence of very unfavorable local conditions and without any dental treatment. These beneficial effects upon the gingiva were observed as the result of either the local or the systemic administration of penicillin. Brodsky and Herschfu$ reported that definite evidence of improvement was observed in eleven of thirteen cases of periodontoclasia after the oral administration of fourteen penicillin tablets (25,000 units) per day for three to fifteen days in three-day series. Brodsky and Herschfus did not describe in detail the condition of the periodontal tissues However, they reported a slight improvebefore the treatment was begun. ment in three cases where gingival bleeding or suppuration was diminished. The results in eight cases were reported as good or improved where gingival hemorrhage and/or suppuration was eliminated. Roth3 administered various dosages of Aureomycin orally for long periods, ranging from one to thirty-six These months, to thirty-one patients with a variety of periodontal problems. patients were maintained also on a special dietary regimen which was low in carbohydrates and fats, high in proteins and minerals, and supplemented with t,hree therapeutic multi-vitamin capsules daily. Roth reported moderat,e to
R
From This
the Harvard School of Dental Medicine. investigation was supported in part by research grants National Institute of Dental Research, Public Health Service, and Inc., New York, New York. We are indebted to Merck 8~ Company, Inc., Rahway, New of vitamin B complex. *Present address : New York University College of Dentistry, Guggenheim Foundation Institute for Dental Research, New York, 1169
D-100 and D-322 from the The Nutrition Foundation, Jersey, New
the
for Murray York.
ample and
supplies Leonie
marked improvement in the condition of the periodontal tissues in all paticnt,s. No detailed description of the gingivnl tissue and alveolar bone before or after the treatment was reported. Also Roth did not mention that part of the bentficial effect may have been due to the modified diet, with its low carbohydrate level and its high protein and vitamin conttlnts. No studies are known to have been reported in the literature on the effects of antibiotics on the incidence of periodontal disease in experimental animals. The purpose of the present study was to explore the effects of penicillin and streptomycin on the initiation and progression of periodontal lesions in the rice rat whose susceptibility to periodontal disease ha,s been reported previ0usly.4 j
Experimental Four experiments were conducted. The first and second experiments were designed to study the effects of 0.05 per cent penicillin and 0.05 per cent streptomycin as supplements t,o either ration 4 or ration 700 on the incidence of periodontal lesions in the rice rat. The ob*ject of the third experiment was to test the effects of lower levels of these antibiotics and to seek confirmation of the findings from the first two experiments. The fourth experiment was designed to study the curative abilities o-f these antibiotics. In the four experiments, weanling littermates of rice rats were used: t,hey were distributed as evenly as possible wit,h respect to sex and weight among the groups in each experiment,. Tn the first experiment, t,hirty-sercn rice rats were divided into t,hrcc groups of eleven, twelve, and fourteen, respectively. The subjects in the first group were fed Keyes’s cariogenic ration 4.6 while those in the second group were mainta,ined on ration 4 to which 0.05 per cent penicillin was added. The animals in the third group were given ration 4 supplemented with 0.05 per cent streptomycin. The second experiment wit,h fifty-two rice rat,s distributed into three groups of seventeen, nineteen, and sixteen, respectively, was similar in design to the first one, except that the rice rats were maintained on Harvard cariogenic ration 7007 instead of ration 4. The rats in G-roup 1 were maintained as controls, while those in Groups 2 and 3 aga.in received 0.05 per cent penicillin or 0.05 per cent streptomycin, respectively. Tn the third experiment, forty-sttvcn rice rats were distributed into five comparable groups of ten, nine. ten, eight and ten, respectively. The subjects in these five groups received ration ‘700, ration 700 plus 0.05 per cent penicillin, ration 700 plus 0.01 per cent I)cnicillin, ration 700 plus 0.05 per cent strcptomycin, and rat,ion 700 plus 0.01 per cent streptomycin, respectively. All the animals in experiments 1. 2. and 3 were 1 given their diets and water ad libitum for a period of twenty-one weeks. Tn the fourt,h experiment, seventy-caight rice rats wcro distributed into I’out groups of twenty-two, sevent,ecn, twenty-one, and eighteen anima.ls, respectively. The subjects in all groups were given ration 700 ad libitum for fourteen
Volume 10 Number I I
PERIODONTAL
DISEASE
IN
RICE
RAT
1171
weeks, after which the first group was continued on ration 700 for an additional seven weeks. The rice rats in the third and fourth groups were transferred for an additional seven weeks to ration 700 plus 0.05 per cent penicillin and ration 700 plus 0.05 per cent streptomycin, respectively. The rice rats in the second group were sacrificed after the first fourteen weeks in order to give an appraisal of the amount of periodontal disease prior to beginning antibiotic therapy. All rats were housed in individual wire-bottom cages with their own water bottles and food cups. They were kept in an air-conditioned, temperature- and humidity-controlled animal house. At the end of the appropriate experimental period, the animals were sacrificed and their heads were preserved in 95 per cent alcohol for forty-eight hours. The heads were then skinned and the ora. tissues were examined under a binocular microscope at a magnification of x30. The evaluation of periodontal lesions was done by the method of Gupta and Shaw.5 The total periodontal score in both the soft and hard tissues was expressed in two ca,tegories, namely, the number of areas with periodontal lesions and the extent of periodontal lesions.
Results In the four experiments, the rice rats in all groups grew at normal and practically identical rates and attained comparable adult body weights. In all experiments, no isolated or discrete areas with impacted foods were observed in the soft tissues of the animals. The lesions in both the soft and calcified tissues were observed to be generalized in nature. The average number of areas with periodontal lesions and the average extent of periodontal lesions in the soft and hard tissues of the animals in the four experiments are given in Table I. In Experiments 1 and 2, the rice rats in Groups 2 and 3 that received supplements of 0.05 per cent penicillin or 0.05 per cent streptomycin, respectively, had a greatly reduced incidence of soft tissue lesions when expressed in terms of either category (that is, the average number of periodontal lesions or the average extent of periodontal lesions) than their control littermates in Group 1. These differences in soft tissue lesions between Groups 1 and 2 and between Groups 1 and 3 in both experiments were observed to be stat,istically highly significant. In Experiment 1, the calcified tissue lesions were less extensive in the antibiotic-supplemented animals than in their controls in Group 1. These differences for Groups 2 and 3, when compared to Group 1, were of borderline significance. However, there were no differences in the number of periodontally involved areas since all rats on ration 4 had a completely generalized bone loss involving all twenty-eight areas. The incidence and extent of lesions in the calcified tissues was also found to be much lower for the rice rats in Groups 2 and 3 in Experiment 2 than for the comparable lesions in their littermates in Group 1. These differences between Groups 1 and 2 and Groups 1 and 3 were highly significant.
1172
GtJPTA,
AUSKAPS,
AND
SHAIV
0. S.. 0. M.. & 0. f’. November. 1957
In Experiment 3, the rice rats of Groups 2, 3, 4, and 5 that were fed supplements of 0.05 per cent penicillin, 0.01 per cent penicillin, 0.05 per cent streptomycin, and 0.01 per cent streptomycin, respectively, consistent,ly had a much lower incidence of soft tissue lesions than did the rice rats in Group 1. The differences in the soft tissue lesions between the control animals and those supplemented with either 0.05 per cent penicillin or streptomycin wore statistically highly significant for both categories. The tliffercncc in incidence of Table 1. The effort%
ow
Ration
"f Antibiotics
"" the Incidence aft
x0. of Rats
Number of Periodontal AlW3S A”&
Experiment
4
19.8
11
2
4+ 0.05 % Penicillin
12
3
4+ 0.05 $ Streptanycin
14
(2*5' 4.0 4.4 (0.9)
17
100 + 0.05% Penicillin
19
Experiment
;;;;\ 5
(OA3’
700
700 + 0.05 % Streptomycin
700 700 + 0.05 % Penicillin l
4
700 + 0.05% Streptomycin
5
700 + 0.01 % Streptomycin Experiment
2
3
4
of Periodontal
Extent of Periodontal LeSiO"S Avg. c.rt.t
A”&
‘:
5.9
34.1+ (7.4C)
(0.0)
b _\ /) 4.1 ,'1
4.01 (O.&)
\ 5.8
"
\ 4.4* (0.9+)
'
4.0
Nunber
Ar.%S
c.iLt
Tissues Extent Of Periodontal Lesions c.n.t Avg.
28.0
:
28.0 (0.0)
/\
28.0 (0.0'
'/
\’ \I
0.0 \ ,l
0.0 (1.6*)
16
55.2~ (11.7+)
10 9
66.7* (9.1*) 4.6
t cx+,
4 3
3.2 700
0.01 % Penicillin
1
Calcified
Tissues
4.0
3
in the Rice flat.*
3.
1 2
Lesions
1.
1
3
CA1
of Periodontal
3.5+
10 3.9 8 1.4 10
0.6+ (0.1+' (1.6+) 25.7+ (11.3+)
4.6 1. I'
1.8
3.8
21.2 ’ (1.2)
4.2
(2.0) 17.9 23.4 (1.3)
5
30.7+ (2.W) 3.7
+ $:S,
4.6
22.6+ (3.3*)
2.2
1.4 47.6~ (9.9*)
4.
700 -- 21 weeks 700 -- 14 weeks 700 -700 + 0.05 lin -700 -700 + 0.05 mycin --
14 weeks; i Penicil7 weeks 14 weeks; x Strepto7 weeks
22 17
lR.5
(2.3)
0.2
1.2
59.4+
(4.5*) 0.9
2.1
50.1+ (6.5+)
0.0
0.5 44.9+ (5.1+)
21 0.9 18
55.2+ (La+)
1
q:::
The value in parentheses represents the standard error oP the mean. t C.R.--Critical ratio. The critical ratio is the ratio of the difference between two means to the standard error of the difference between the nea"s. Wherever the critical ratio is less than 2.0, the difference between the means is considered to be statistically insi+fjcant; when 2.0 to 2.9, moderately significant; when 3.0 or higher, highly significant.
Volume IO Number 11
PERIODONTAL
DISEASE
IN
RICE
RAT
1173
soft tissue lesions between the control rats in Group 1 and the rice rats fed the 0.01 per cent penicillin supplement was also highly significant for both the average number of periodontal lesions and the average extent of periodontal lesions. However, the dift’erence in soft tissue lesions between the control subjects in Group 1 and those fed the 0.01 per cent streptomycin supplement was not of significance for the two categories. The incidence of calcified tissue lesions for the rats of Groups 2, 3, 4, and 5 was found to be lower than the calcified lesions of Group 1 for the average number and extent of periodontal lesions. These differences between Groups 1 and 2, 1 and 3, and 1 and 4 were found to be statistically highly significant for both the average number and the average extent of periodontal lesions. The differences in the calcified tissue lesions between Groups 1 and 5 were found to be moderately significant for the average number of periodontal lesions and were insignificant for the average extent of periodontal lesions. In Experiment 4, penicillin at a 0.05 per cent level had a moderately significant effect in arresting and healing the periodontal lesions in the rice rat. Animals placed on the antibiotic regimen at the end of the fourteenth experimental week, after extensive periodontal problems had developed, and then maintained on 0.05 per cent penicillin in ration 700 for the last seven weeks had significantly fewer periodontal lesions in the soft tissues than the control animals maintained on ration 700 for the entire twenty-one experimental weeks. The calcified periodontal tissues in the penicillin-treated animals had fewer and less extensive lesions than the control animals sacrificed at the fourteenth experimental week. This latter reduction in the amount and extent of periodontal lesions in the calcified tissues of the penicillin-treated animals was not statistically significant. These experimental findings suggest that penicillin can arrest the progression of well-advanced periodontal lesions in this species and also permit some healing of the lesions. Streptomycin had less value in arresting the disease process and was completely ineffective as a therapeutic agent for periodontal disease in the rice rat at the 0.05 per cent level. In all four experiments the beneficial effects of antibiotics appeared to be greater on the soft tissue lesions than on the calcified tissue lesions. Moreover, the experimental animals did not show any gastrointestinal disturbances, which might have been expected by reason of the prolonged administration of the antibiotics. Discussion From the results of these four experiments, it is clear that the periodontal syndrome in the rice rat has a strong bacterial component that is susceptible The administration of 0.05 per cent to modification by antibiotic therapy. penicillin or 0.05 per cent streptomycin as a supplement to either ration 4 or ration 700 or of 0.01 per cent penicillin as a supplement to ration 700 caused highly significant reductions in the initiation and progression of lesions in the soft tissues of the periodontium. These levels of antibiotics, when fed from weaning until the conclusion of the twenty-one-week experimental period,
1174
GUPTA,
AUSKAPS,
AXI)
SHAW
0. s.. 0. M., & 0. P. November.
1957
were partially effective in the prevention of lesions of the alveolar boric. However, alveolar bone resorpt,ion continued to progress at a substantial rate in the presence of these antibiotics. A supplcmcnt of 0.01 per cent streptomycin was much less effective than the supplcmcnt of 0.01 per cent penicillin in the prevention of soft tissue lesions. From a curative standpoint, the effects of penicillin and streptomycin at the 0.05 per cent level of supplementation to ration 700 were much less striking than the results in the three experiments where their prophylactic properties were studied. Only penicillin caused a major reduction in the incidence and extent of soft tissue lesions and a minor reduction in lesions in the alveolar bone, when fed during the last seven weeks only of the experimental period. This reduction in soft tissue lesions represented a significant amount of healing of the soft tissue lesions, but the influence on the alveolar bone was of borderline significance. Streptomycin at the same level was effective in inhibiting the further advance of soft tissue lesions during the last seven weeks of the cxperiment but had no ability to enable the existing lesions to regress. Thus, penicillin in both the prophylactic and curative trials appears to be somewhat superior to streptomycin in the periodontal syndrome of t,he rice rat. The mechanism of action of penicillin and streptomycin on the initiation The fact and progression of periodontal lesions needs further exploration. that both penicillin and streptomycin were effective in the prevention of the periodontal syndrome in the rice rat is surprising, since both of these antibiotics have comparatively narrow spectra that are complet,ely opposite to each other. Other antibiotics should be tested for their respective ability t.o alter the initiation and progression of lesions in the periodontium of the rice rat. Further studies should be undertaken to evaluate the degree to which lesions of the soft tissues of the periodontium and alveolar bone resorption may be independent of each other. Throughout these experiments the degree to which alveolar bone resorption occurred in the absence of any appreciable amount of pathology in the gingival tissues raises numerous questions for which answers are not available presently. Summary Two hundred fourteen rice rats were used in four experiments to test the prophylactic and curative abilities of penicillin and streptomycin on the periodontal syndrome. Supplements of 0.05 per cent penicillin or of 0.05 per cent streptomycin to ration 4 or ration 700 throughout the twenty-one-week experimental period caused major reductions in the number and extent of soft tissue lesions but much smaller reductions in the amount of alveolar bone resorption. A supplement of 0.01 per cent penicillin to ration 700 was also highly effective in the prevention of periodontal lesions, while a comparable supplement of streptomycin was much less effective. Supplements of 0.05 per cent penicillin or 0.05 per cent streptomycin to ration 700 during the last seven weeks of the experimental period were much
Volume IO Number I1
PERIODONTAL
DISEASE
IN
RICE
RAT
1175
less effective. Penicillin caused a moderate amount of healing of existing lesions of the soft tissues,while streptomycin did not encourage healing but did prevent further progression of soft tissue lesions. Neither had any striking infIucncc on the resorption of alveolar hone in thr curative test. References 1. Atrock, 2. Brodsky, 3. Roth, 4. Gupta, 3. Gupta, 6. Keyes, 7. Shaw,
A. Dent.
E.: Relationship Between Gingivitis and Penicillin Administration, J. Am. A. 31: 1235, 1944. R. H., and Herschfus, L.: Oral Penicillin in the Treatment of Oral Lesions, Quart. Bull., Sea View Hosp. 8: 55, 1946. 1~. H.: A Report of Long Sustained Therapy With Chlortetracycline, Antibiotic Med. 1: 13, 1955. 0. P., and Shaw, J. H.: Periodontal Disease in the Rice Rat. I. Anatomic am1 Histopathologic Findings, ORAL SURG., ORAL MED. & ORAL PATH. 9: 592, 1956. 0. I’., and Shaw, J. H.: Periodontal Disease in the Rice Rat. II. Methods for the Evaluation of the Extent of Periodontal Disease, ORAL SURG., ORAL MED. & ORAL PATH.~: 727,1956. Dental Caries in the Syrian Hamster. VII. Increased Dental Caries P. H.: Activity in Animals Fed Whole-wheat Ash Diets During the Odontogenic Period, J. D. Res. 35: 95, 1956. J. H.: The Effect of Carbohydrate-free and Carbohydrate-low Diets on the Incidence of Dental Caries in White Rats, J. Nutrition 53: 151, 1954.
The Effects
OM P.
GUPTA,
of Antibiotics
DISEASE
IN THE RICE RAT
on the Incidence
of Periodontal
B.D.S., M.S.,* AINA M. AUSKAPS, D.M.D., SHAW, PH.D., BOSTON, MASS.
AND
Lesions
JAMES
H.
ELATIVELY few studies have been reported on the effects of antibiotic administration on the manifestations of periodontal disease in human beings. Strockl was among the first to report on the beneficial influence of penicillin upon the gingival tissues. He observed 198 male patients who had received total penicillin dosages of 80,000 to 9,000,OOOunits in the treatment of various infections, including syphilis, gonorrhea, osteomyelitis, septicemia, etc. He stated that a marked improvement was observed in the condition of the gingival tissues, with better tissue tone, less tendency to bleed, and a remarkable ability to heal. These improvements occurred even in the presence of very unfavorable local conditions and without any dental treatment. These beneficial effects upon the gingiva were observed as the result of either the local or the systemic administration of penicillin. Brodsky and Herschfu$ reported that definite evidence of improvement was observed in eleven of thirteen cases of periodontoclasia after the oral administration of fourteen penicillin tablets (25,000 units) per day for three to fifteen days in three-day series. Brodsky and Herschfus did not describe in detail the condition of the periodontal tissues However, they reported a slight improvebefore the treatment was begun. ment in three cases where gingival bleeding or suppuration was diminished. The results in eight cases were reported as good or improved where gingival hemorrhage and/or suppuration was eliminated. Roth3 administered various dosages of Aureomycin orally for long periods, ranging from one to thirty-six These months, to thirty-one patients with a variety of periodontal problems. patients were maintained also on a special dietary regimen which was low in carbohydrates and fats, high in proteins and minerals, and supplemented with t,hree therapeutic multi-vitamin capsules daily. Roth reported moderat,e to
R
From This
the Harvard School of Dental Medicine. investigation was supported in part by research grants National Institute of Dental Research, Public Health Service, and Inc., New York, New York. We are indebted to Merck 8~ Company, Inc., Rahway, New of vitamin B complex. *Present address : New York University College of Dentistry, Guggenheim Foundation Institute for Dental Research, New York, 1169
D-100 and D-322 from the The Nutrition Foundation, Jersey, New
the
for Murray York.
ample and
supplies Leonie
marked improvement in the condition of the periodontal tissues in all paticnt,s. No detailed description of the gingivnl tissue and alveolar bone before or after the treatment was reported. Also Roth did not mention that part of the bentficial effect may have been due to the modified diet, with its low carbohydrate level and its high protein and vitamin conttlnts. No studies are known to have been reported in the literature on the effects of antibiotics on the incidence of periodontal disease in experimental animals. The purpose of the present study was to explore the effects of penicillin and streptomycin on the initiation and progression of periodontal lesions in the rice rat whose susceptibility to periodontal disease ha,s been reported previ0usly.4 j
Experimental Four experiments were conducted. The first and second experiments were designed to study the effects of 0.05 per cent penicillin and 0.05 per cent streptomycin as supplements t,o either ration 4 or ration 700 on the incidence of periodontal lesions in the rice rat. The ob*ject of the third experiment was to test the effects of lower levels of these antibiotics and to seek confirmation of the findings from the first two experiments. The fourth experiment was designed to study the curative abilities o-f these antibiotics. In the four experiments, weanling littermates of rice rats were used: t,hey were distributed as evenly as possible wit,h respect to sex and weight among the groups in each experiment,. Tn the first experiment, t,hirty-sercn rice rats were divided into t,hrcc groups of eleven, twelve, and fourteen, respectively. The subjects in the first group were fed Keyes’s cariogenic ration 4.6 while those in the second group were mainta,ined on ration 4 to which 0.05 per cent penicillin was added. The animals in the third group were given ration 4 supplemented with 0.05 per cent streptomycin. The second experiment wit,h fifty-two rice rat,s distributed into three groups of seventeen, nineteen, and sixteen, respectively, was similar in design to the first one, except that the rice rats were maintained on Harvard cariogenic ration 7007 instead of ration 4. The rats in G-roup 1 were maintained as controls, while those in Groups 2 and 3 aga.in received 0.05 per cent penicillin or 0.05 per cent streptomycin, respectively. Tn the third experiment, forty-sttvcn rice rats were distributed into five comparable groups of ten, nine. ten, eight and ten, respectively. The subjects in these five groups received ration ‘700, ration 700 plus 0.05 per cent penicillin, ration 700 plus 0.01 per cent I)cnicillin, ration 700 plus 0.05 per cent strcptomycin, and rat,ion 700 plus 0.01 per cent streptomycin, respectively. All the animals in experiments 1. 2. and 3 were 1 given their diets and water ad libitum for a period of twenty-one weeks. Tn the fourt,h experiment, seventy-caight rice rats wcro distributed into I’out groups of twenty-two, sevent,ecn, twenty-one, and eighteen anima.ls, respectively. The subjects in all groups were given ration 700 ad libitum for fourteen
Volume 10 Number I I
PERIODONTAL
DISEASE
IN
RICE
RAT
1171
weeks, after which the first group was continued on ration 700 for an additional seven weeks. The rice rats in the third and fourth groups were transferred for an additional seven weeks to ration 700 plus 0.05 per cent penicillin and ration 700 plus 0.05 per cent streptomycin, respectively. The rice rats in the second group were sacrificed after the first fourteen weeks in order to give an appraisal of the amount of periodontal disease prior to beginning antibiotic therapy. All rats were housed in individual wire-bottom cages with their own water bottles and food cups. They were kept in an air-conditioned, temperature- and humidity-controlled animal house. At the end of the appropriate experimental period, the animals were sacrificed and their heads were preserved in 95 per cent alcohol for forty-eight hours. The heads were then skinned and the ora. tissues were examined under a binocular microscope at a magnification of x30. The evaluation of periodontal lesions was done by the method of Gupta and Shaw.5 The total periodontal score in both the soft and hard tissues was expressed in two ca,tegories, namely, the number of areas with periodontal lesions and the extent of periodontal lesions.
Results In the four experiments, the rice rats in all groups grew at normal and practically identical rates and attained comparable adult body weights. In all experiments, no isolated or discrete areas with impacted foods were observed in the soft tissues of the animals. The lesions in both the soft and calcified tissues were observed to be generalized in nature. The average number of areas with periodontal lesions and the average extent of periodontal lesions in the soft and hard tissues of the animals in the four experiments are given in Table I. In Experiments 1 and 2, the rice rats in Groups 2 and 3 that received supplements of 0.05 per cent penicillin or 0.05 per cent streptomycin, respectively, had a greatly reduced incidence of soft tissue lesions when expressed in terms of either category (that is, the average number of periodontal lesions or the average extent of periodontal lesions) than their control littermates in Group 1. These differences in soft tissue lesions between Groups 1 and 2 and between Groups 1 and 3 in both experiments were observed to be stat,istically highly significant. In Experiment 1, the calcified tissue lesions were less extensive in the antibiotic-supplemented animals than in their controls in Group 1. These differences for Groups 2 and 3, when compared to Group 1, were of borderline significance. However, there were no differences in the number of periodontally involved areas since all rats on ration 4 had a completely generalized bone loss involving all twenty-eight areas. The incidence and extent of lesions in the calcified tissues was also found to be much lower for the rice rats in Groups 2 and 3 in Experiment 2 than for the comparable lesions in their littermates in Group 1. These differences between Groups 1 and 2 and Groups 1 and 3 were highly significant.
1172
GtJPTA,
AUSKAPS,
AND
SHAIV
0. S.. 0. M.. & 0. f’. November. 1957
In Experiment 3, the rice rats of Groups 2, 3, 4, and 5 that were fed supplements of 0.05 per cent penicillin, 0.01 per cent penicillin, 0.05 per cent streptomycin, and 0.01 per cent streptomycin, respectively, consistent,ly had a much lower incidence of soft tissue lesions than did the rice rats in Group 1. The differences in the soft tissue lesions between the control animals and those supplemented with either 0.05 per cent penicillin or streptomycin wore statistically highly significant for both categories. The tliffercncc in incidence of Table 1. The effort%
ow
Ration
"f Antibiotics
"" the Incidence aft
x0. of Rats
Number of Periodontal AlW3S A”&
Experiment
4
19.8
11
2
4+ 0.05 % Penicillin
12
3
4+ 0.05 $ Streptanycin
14
(2*5' 4.0 4.4 (0.9)
17
100 + 0.05% Penicillin
19
Experiment
;;;;\ 5
(OA3’
700
700 + 0.05 % Streptomycin
700 700 + 0.05 % Penicillin l
4
700 + 0.05% Streptomycin
5
700 + 0.01 % Streptomycin Experiment
2
3
4
of Periodontal
Extent of Periodontal LeSiO"S Avg. c.rt.t
A”&
‘:
5.9
34.1+ (7.4C)
(0.0)
b _\ /) 4.1 ,'1
4.01 (O.&)
\ 5.8
"
\ 4.4* (0.9+)
'
4.0
Nunber
Ar.%S
c.iLt
Tissues Extent Of Periodontal Lesions c.n.t Avg.
28.0
:
28.0 (0.0)
/\
28.0 (0.0'
'/
\’ \I
0.0 \ ,l
0.0 (1.6*)
16
55.2~ (11.7+)
10 9
66.7* (9.1*) 4.6
t cx+,
4 3
3.2 700
0.01 % Penicillin
1
Calcified
Tissues
4.0
3
in the Rice flat.*
3.
1 2
Lesions
1.
1
3
CA1
of Periodontal
3.5+
10 3.9 8 1.4 10
0.6+ (0.1+' (1.6+) 25.7+ (11.3+)
4.6 1. I'
1.8
3.8
21.2 ’ (1.2)
4.2
(2.0) 17.9 23.4 (1.3)
5
30.7+ (2.W) 3.7
+ $:S,
4.6
22.6+ (3.3*)
2.2
1.4 47.6~ (9.9*)
4.
700 -- 21 weeks 700 -- 14 weeks 700 -700 + 0.05 lin -700 -700 + 0.05 mycin --
14 weeks; i Penicil7 weeks 14 weeks; x Strepto7 weeks
22 17
lR.5
(2.3)
0.2
1.2
59.4+
(4.5*) 0.9
2.1
50.1+ (6.5+)
0.0
0.5 44.9+ (5.1+)
21 0.9 18
55.2+ (La+)
1
q:::
The value in parentheses represents the standard error oP the mean. t C.R.--Critical ratio. The critical ratio is the ratio of the difference between two means to the standard error of the difference between the nea"s. Wherever the critical ratio is less than 2.0, the difference between the means is considered to be statistically insi+fjcant; when 2.0 to 2.9, moderately significant; when 3.0 or higher, highly significant.
Volume IO Number 11
PERIODONTAL
DISEASE
IN
RICE
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soft tissue lesions between the control rats in Group 1 and the rice rats fed the 0.01 per cent penicillin supplement was also highly significant for both the average number of periodontal lesions and the average extent of periodontal lesions. However, the dift’erence in soft tissue lesions between the control subjects in Group 1 and those fed the 0.01 per cent streptomycin supplement was not of significance for the two categories. The incidence of calcified tissue lesions for the rats of Groups 2, 3, 4, and 5 was found to be lower than the calcified lesions of Group 1 for the average number and extent of periodontal lesions. These differences between Groups 1 and 2, 1 and 3, and 1 and 4 were found to be statistically highly significant for both the average number and the average extent of periodontal lesions. The differences in the calcified tissue lesions between Groups 1 and 5 were found to be moderately significant for the average number of periodontal lesions and were insignificant for the average extent of periodontal lesions. In Experiment 4, penicillin at a 0.05 per cent level had a moderately significant effect in arresting and healing the periodontal lesions in the rice rat. Animals placed on the antibiotic regimen at the end of the fourteenth experimental week, after extensive periodontal problems had developed, and then maintained on 0.05 per cent penicillin in ration 700 for the last seven weeks had significantly fewer periodontal lesions in the soft tissues than the control animals maintained on ration 700 for the entire twenty-one experimental weeks. The calcified periodontal tissues in the penicillin-treated animals had fewer and less extensive lesions than the control animals sacrificed at the fourteenth experimental week. This latter reduction in the amount and extent of periodontal lesions in the calcified tissues of the penicillin-treated animals was not statistically significant. These experimental findings suggest that penicillin can arrest the progression of well-advanced periodontal lesions in this species and also permit some healing of the lesions. Streptomycin had less value in arresting the disease process and was completely ineffective as a therapeutic agent for periodontal disease in the rice rat at the 0.05 per cent level. In all four experiments the beneficial effects of antibiotics appeared to be greater on the soft tissue lesions than on the calcified tissue lesions. Moreover, the experimental animals did not show any gastrointestinal disturbances, which might have been expected by reason of the prolonged administration of the antibiotics. Discussion From the results of these four experiments, it is clear that the periodontal syndrome in the rice rat has a strong bacterial component that is susceptible The administration of 0.05 per cent to modification by antibiotic therapy. penicillin or 0.05 per cent streptomycin as a supplement to either ration 4 or ration 700 or of 0.01 per cent penicillin as a supplement to ration 700 caused highly significant reductions in the initiation and progression of lesions in the soft tissues of the periodontium. These levels of antibiotics, when fed from weaning until the conclusion of the twenty-one-week experimental period,
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were partially effective in the prevention of lesions of the alveolar boric. However, alveolar bone resorpt,ion continued to progress at a substantial rate in the presence of these antibiotics. A supplcmcnt of 0.01 per cent streptomycin was much less effective than the supplcmcnt of 0.01 per cent penicillin in the prevention of soft tissue lesions. From a curative standpoint, the effects of penicillin and streptomycin at the 0.05 per cent level of supplementation to ration 700 were much less striking than the results in the three experiments where their prophylactic properties were studied. Only penicillin caused a major reduction in the incidence and extent of soft tissue lesions and a minor reduction in lesions in the alveolar bone, when fed during the last seven weeks only of the experimental period. This reduction in soft tissue lesions represented a significant amount of healing of the soft tissue lesions, but the influence on the alveolar bone was of borderline significance. Streptomycin at the same level was effective in inhibiting the further advance of soft tissue lesions during the last seven weeks of the cxperiment but had no ability to enable the existing lesions to regress. Thus, penicillin in both the prophylactic and curative trials appears to be somewhat superior to streptomycin in the periodontal syndrome of t,he rice rat. The mechanism of action of penicillin and streptomycin on the initiation The fact and progression of periodontal lesions needs further exploration. that both penicillin and streptomycin were effective in the prevention of the periodontal syndrome in the rice rat is surprising, since both of these antibiotics have comparatively narrow spectra that are complet,ely opposite to each other. Other antibiotics should be tested for their respective ability t.o alter the initiation and progression of lesions in the periodontium of the rice rat. Further studies should be undertaken to evaluate the degree to which lesions of the soft tissues of the periodontium and alveolar bone resorption may be independent of each other. Throughout these experiments the degree to which alveolar bone resorption occurred in the absence of any appreciable amount of pathology in the gingival tissues raises numerous questions for which answers are not available presently. Summary Two hundred fourteen rice rats were used in four experiments to test the prophylactic and curative abilities of penicillin and streptomycin on the periodontal syndrome. Supplements of 0.05 per cent penicillin or of 0.05 per cent streptomycin to ration 4 or ration 700 throughout the twenty-one-week experimental period caused major reductions in the number and extent of soft tissue lesions but much smaller reductions in the amount of alveolar bone resorption. A supplement of 0.01 per cent penicillin to ration 700 was also highly effective in the prevention of periodontal lesions, while a comparable supplement of streptomycin was much less effective. Supplements of 0.05 per cent penicillin or 0.05 per cent streptomycin to ration 700 during the last seven weeks of the experimental period were much
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less effective. Penicillin caused a moderate amount of healing of existing lesions of the soft tissues,while streptomycin did not encourage healing but did prevent further progression of soft tissue lesions. Neither had any striking infIucncc on the resorption of alveolar hone in thr curative test. References 1. Atrock, 2. Brodsky, 3. Roth, 4. Gupta, 3. Gupta, 6. Keyes, 7. Shaw,
A. Dent.
E.: Relationship Between Gingivitis and Penicillin Administration, J. Am. A. 31: 1235, 1944. R. H., and Herschfus, L.: Oral Penicillin in the Treatment of Oral Lesions, Quart. Bull., Sea View Hosp. 8: 55, 1946. 1~. H.: A Report of Long Sustained Therapy With Chlortetracycline, Antibiotic Med. 1: 13, 1955. 0. P., and Shaw, J. H.: Periodontal Disease in the Rice Rat. I. Anatomic am1 Histopathologic Findings, ORAL SURG., ORAL MED. & ORAL PATH. 9: 592, 1956. 0. I’., and Shaw, J. H.: Periodontal Disease in the Rice Rat. II. Methods for the Evaluation of the Extent of Periodontal Disease, ORAL SURG., ORAL MED. & ORAL PATH.~: 727,1956. Dental Caries in the Syrian Hamster. VII. Increased Dental Caries P. H.: Activity in Animals Fed Whole-wheat Ash Diets During the Odontogenic Period, J. D. Res. 35: 95, 1956. J. H.: The Effect of Carbohydrate-free and Carbohydrate-low Diets on the Incidence of Dental Caries in White Rats, J. Nutrition 53: 151, 1954.