Effect of Oral Contraceptive Therapy On Gingival Inflammation in Humans
traceptives were compared to those who were not. The purpose of this study was to investigate whether particular brands of oral contraceptives or total accu mulated exposure to oral contraceptives affected gingival inflammation in humans. MATERIALS AND METHODS
One hundred eighty-nine patients who met the follow ing criteria were selected for study from the undergrad uate restorative dentistry clinic of the University of Nebraska College of Dentistry: (1) Female, (2) Between ages 18 and 35, (3) No professional plaque control instructions or oral prophylaxis within the last 30 days, (4) At least one professional prophylaxis within the last 12 months. The following reference areas were selected for obtain ing an Oral Debris Index and a Gingival Inflammatory Index: (1) Upper left first molar, mesial-facial line angle; (2) Lower right first molar, mesial-lingual line angle; (3) Upper left central incisor, mesial-facial line angle; (4) Lower right central incisor, mesial-facial line angle. The patient must have had at least three of these reference teeth present in the mouth to be included in the study. If one reference tooth was missing, the first tooth from that position in a mesial direction was scored. All evaluations were completed by one examiner who had no prior knowledge of the patient's history of oral contraceptive consumption. Each of the reference areas was first observed and scored with a Gingival Inflammatory Index (modified Gingival Index, Löe and Silness, 1963) using the follow ing criteria:
by K E N N E T H L . K A L K W A R F , D.D.S., M.S.* SEVERAL STUDIES have observed a relationship between altered levels of sex hormones and variations in degree of gingival inflammation. Earlier works " observed in creased gingival inflammation in females during preg nancy. The rise in inflammation closely paralleled an increase in the blood level of the hormones estrogen and progesterone seen during pregnancy. Since the gingival inflammation and the hormone levels subsided following parturition, it was suggested that altered levels of estro gen and progesterone may influence the inflammatory state. Several investigations " studied the effect of hor monal application on soft tissue inflammation in ani mals. Each found that hormonal application resulted in vascular and connective tissue changes. Hugoson longitudinally studied a group of pregnant women and investigated hormone influence on gingival healing. From this work he hypothesized that the aggra vation of gingivitis seen during pregnancy was caused primarily by an elevated level of progesterone and its effect on the microvascular system. ElAttar recently discovered that addition of sex hor mones to gingival tissue caused a significant increase in the synthesis of prostaglandin E . Since E-type prosta glandins are potent mediators of inflammation, expla nation of the mechanism by which sex hormones increase inflammation may be possible. Oral contraceptives have become a very widely used form of birth control during the past two decades. Since all oral contraceptives act by artificially altering sex hormone levels, their influence on gingival inflammation has been studied. Lindhe and Bjorn showed a significant increase of gingival fluid in individuals taking oral contraceptives. This was later supported by Grower et al. Lynn and Kaufman each described an episode of hyperplastic gingivitis that was related to ingestion of oral contraceptives. El-Ashiry ' found females taking oral contraceptives revealed states of gingival inflammation very similar to pregnant individuals. Knight and Wade found no statistically significant differences between plaque scores, gingival scores or losses of attachment when individuals taking oral con 1
5
4
12
13
0 = Clinically normal gingiva 1 = Mild inflammation with no bleeding on gentle manipulation of the sulcus with a probe 2 = Moderate inflammation with bleeding upon gentle manipulation of the sulcus 3 = Severe inflammation with sulcular ulceration and spontaneous bleeding upon gentle manipu lation Following recording of the Gingival Inflammatory Index, a two-tone disclosing solution† was applied to the teeth and the same reference areas were evaluated for debris using the following criteria:
14
2
15
0 = No disclosable material present at the gingival margin 1 = A pink film present at the gingival margin 2 = A moderate accumulation of dark pink or blue staining material present at the marginal area 3 = An abundance of blue to purple staining material present at the gingival margin
16
17
18
19 20
Following the completion of the clinical examination, the patient was asked to complete a questionnaire cov ering the following areas: 1. Current usage of oral contraceptives. If the patient
21
* Department of Periodontology, College of Dentistry, University of Nebraska—Lincoln, Lincoln, Neb 68583.
† Dis-plaque® (Pacemaker Corporation, Portland, Oregon) 560
Volume 49 Number 11
Oral Contraceptive
was currently taking oral contraceptives, the brand name and the time period they had been taking the present brand was recorded. 2. Total accumulative months they had taken oral contraceptives throughout their lives. 3. Any other medications they were currently taking or had taken for more than 2 continuous weeks within the past year. 4. Any systemic diseases or conditions, such as preg nancy, that presently existed. Of the 189 patients, 18 were eliminated from the study because of medications or systemic conditions which may have had an influence upon their gingival tissues. Three individuals were eliminated from the study be cause of discontinuance of oral contraceptive therapy within the past 8 weeks. Following dismissal of the patient, a mean Oral Debris Index and a mean Gingival Inflammatory Index were compiled and the data obtained were submitted to sta tistical analysis. The study was divided into three sections: Part I. Current Use of Oral Contraceptives Group A—Yes Group B—No (Control) Part II. Brand of Oral Contraceptive Currently Being Taken Group B—None (Control) Group C—Ovulen Group D—Norinyl 1 + 50 Group E—Norlestrin Group F—Demulen Group G—Ovral Group H—Norinyl 1 + 80 Group I—Ortho-Novum 1/80 Group J—Ortho-Novum 1/50 Group K—Oracon Group L—Enovid-E Part III. Total Accumulated Exposure to Oral Con traceptives Group M—No exposure (Control) Group N—1-11 months Group O—12-35 months Group P—36 or more months Each member of each group met the original criteria for patient selection. No attempt was made to match individuals between the groups. A mean Oral Debris Index and a mean Gingival Inflammatory Index was compiled for each group. Within each part of the study, a pooled variance estimate compared the mean indices of each group with every other group. RESULTS
Part I . When all individuals presently taking oral contracep tives were pooled and compared to the group not cur rently taking oral contraceptives, the following observa tions were evident (Table 1):
Therapy
561
1. The group currently taking oral contraceptives pos sessed a higher Gingival Inflammatory Index (P < 0.001). 2. The group taking oral contraceptives possessed a lower Oral Debris Index (P < 0.04). Part I I . The 93 individuals taking oral contraceptives were divided into groups (Table 2). Three of these groups were not considered for individual statistical analysis. The Norlestrin (E) and Enovid-E (L) groups consisted of too few members to be conclusive. The Oracon group (K) was not evaluated because it was a sequential-type contraceptive and since has been removed from the market by the United States Federal Drug Administra tion. The majority of the oral contraceptives consisted of 1.0 mg of progestin compound and 50 to 80 meg of estrogen. The notable exceptions were Ovulen which contained 100 meg of estrogen and Ovral which con tained 0.5 mg of progestin. Norinyl 1 + 50 (D) and Ovral (G) demonstrated a statistically significant lower Oral Debris Index at the 5% level of confidence or better when compared with the group that was not taking oral contraceptives. Ovulen (C), Ovral (G) and Norinyl 1/80 (I) revealed a signifi cantly higher Gingival Inflammatory Index at the 5% level of confidence or better when compared with a group that was not taking oral contraceptives. TABLE 1. Comparison of Individuals Currently Taking Oral Contracep tives With Individuals Not Taking O r a l Contraceptives
Control
Group
N
I.I. x ± SE
x±SE
A B
93 75
1.49 (0.04) 1.20 (0.05) ( P < 0.001)
0.81 (0.10) 0.95 (0.04) (P < 0.04)
D.I.
N = Number of subjects. I.I. = Gingival Inflammatory Index. D.I. = Oral Debris Index. SE = Standard error of the mean. TABLE 2. Hormone Content, Gingival Inflammatory Index and Oral Debris Index of Each B r a n d of O r a l Contraceptive Group
N
B C D E F G H I J K L
75 25 8 3 6 14 11 9 9 5 2
Estro Progestin gen (meg)
Control
100 50 50 50 50 80 80 50 100 100
I.I.
(mg)
x ± SE
1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 25.0 2.5
1.20 (0.05) 1.47 (0.10) 1.18(0.18) 1.70 (0.46) 1.57 (0.08) 1.49 (0.12) 1.68 (0.12) 1.49 (0.11) 1.44 (0.20) 1.60 (0.14) 1.15 (0.15)
N = Number of subjects. I.I. = Gingival Inflammatory Index. D.I. = Oral Debris Index. SE = Standard error of the mean.
D.I. x±SE 0.95 0.84 0.58 1.20 0.82 0.71 1.00 0.72 0.80 0.84 0.65
(0.05) (0.09) (0.10) (0.56) (0.12) (0.10) (0.15) (0.13) (0.13) (0.16) (0.35)
562
J. Periodontol. November, 1978
Kalkwarf
No significant differences were found in either Oral Debris or Gingival Inflammatory Indices when compar isons between other groups were made. The two oral contraceptive groups having different hormonal compositions (Ovulen with increased estrogen and Ovral with decreased progesterone) revealed very similar effects when compared to the group not taking oral contraceptives. Ovulen showed an increased mean Gingival Inflammatory Index that was significant at the 0.02 level. Ovral exhibited a decreased mean Oral Debris Index, significant at the 0.05 level and an elevated mean Gingival Inflammatory Index, significant at the 0.04 level.
results. While several numerical differences were found to be statistically significant, a clinical or biological difference between some groups may be questionable. Statistical differences found in this study confirm pre vious findings " ' that gingival inflammatory indices are higher for individuals taking oral contraceptives than in subjects not taking such medication. Previous work has shown that this is probably due to the effects of artificially elevated levels of progesterone. Increased pro gesterone levels have been shown to alter microvascular topography and permeability of gingival tissues, ' increase the number of polymorphonuclear leucocytes within the gingival sulcus ' and, in combination with estradiol, increase synthesis of prostaglandin E in gingival tissue. Each of these mechanisms could be responsible for causing an exaggerated gingival inflammatory response to a local irritant. Thus, a persistent accumulation of bacterial plaque at the gingival margin capable of caus ing a low grade inflammation for a female not taking oral contraceptives could produce an exaggerated re sponse if the individual were artificially increasing sys temic progesterone levels by taking oral contraceptives. Clinically, this phenomenon could be important. A low grade "pregnancy gingivitis" could be the result of bac terial plaque accumulation and systematically altered progesterone levels from intake of oral contraceptives. The important difference is that while hormone alter ation is over in a maximum of 9 months with the pregnant individuals; individuals taking oral contracep tives may be altering their hormone levels for much longer periods of time. The Gingival Inflammatory Index used in this study is a slight modification of the Gingival Index introduced by Löe and Silness in 1963. A few of the visual criteria were eliminated in an attempt to eliminate subjectivity. The differences found in gingival inflammatory indi ces between various brands of oral contraceptives were interesting, but not conclusive. A l l brands of oral contra ceptives encountered except one (Ovral) consisted of 1 mg of progestin compound. The progestin was either norethindrone, ethynodiol diacetate or norethynodrel. Ovral contained 0.5 mg of norgestrel and was one of the brands that individually demonstrated a significantly higher Gingival Inflammatory Index when compared to the control group. Each brand consisted of 50, 80 or 100 meg of estrogen compound. The estrogen was either ethinyl estradiol or mestranol. The three groups individually exhibiting sig nificantly higher Gingival Inflammatory Indices (Ovu len, Ovral and Norinyl 1 + 80) consisted of 100 meg of mestranol, 50 meg of ethinyl estradiol and 80 meg of mestranol respectively. The term Oral Debris Index was used in this study rather than Plaque Index. A two-tone disclosing solu tion was applied at the gingival margin of each refer ence area with a cotton swab. The patient was then allowed to rinse once with two ounces of tap water. A l l 15
17 20
6 912
1013
22
2
P a r t III. Mean Oral Debris Indices and mean Gingival Inflam matory Indices of groups with different total accumula tive exposure to oral contraceptives (Table 4) were not statistically different. Sixty-four percent of the individ uals in this study had an accumulative exposure of less than 36 months to oral contraceptives. DISCUSSION
One must be careful in analysis of data from a crosssectional study such as this one. It must be assumed that indices for inflammation and oral debris taken at four line angles (two posterior and two anterior) are repre sentative for that particular patient. Because of several factors (oral hygiene habits, tooth position, etc.) these areas may not be representative for all patients. It must be considered also that factors other than oral debris contribute to clinical gingival inflammation. Sys temic factors, many of which perhaps are nonmeasurable at the present time, may play a role in the severity of gingival inflammation recorded. It is reasonable to assume that selecting the entire sample size from a group that meets selected criteria, distributes these uncontrollable variables. One must be careful also in analysis of the statistical TABLE 3. O r a l Contraceptive M e a n Gingival Inflammatory
Brands Exhibiting Significantly Indices or Mean Oral Debris
Different Indices
Oral Debris Index
Gingival Inflammatory Index C>B(P B ( P < 0.04) H > B (P < 0.002)
D
traceptives were compared to those who were not. The purpose of this study was to investigate whether particular brands of oral contraceptives or total accu mulated exposure to oral contraceptives affected gingival inflammation in humans. MATERIALS AND METHODS
One hundred eighty-nine patients who met the follow ing criteria were selected for study from the undergrad uate restorative dentistry clinic of the University of Nebraska College of Dentistry: (1) Female, (2) Between ages 18 and 35, (3) No professional plaque control instructions or oral prophylaxis within the last 30 days, (4) At least one professional prophylaxis within the last 12 months. The following reference areas were selected for obtain ing an Oral Debris Index and a Gingival Inflammatory Index: (1) Upper left first molar, mesial-facial line angle; (2) Lower right first molar, mesial-lingual line angle; (3) Upper left central incisor, mesial-facial line angle; (4) Lower right central incisor, mesial-facial line angle. The patient must have had at least three of these reference teeth present in the mouth to be included in the study. If one reference tooth was missing, the first tooth from that position in a mesial direction was scored. All evaluations were completed by one examiner who had no prior knowledge of the patient's history of oral contraceptive consumption. Each of the reference areas was first observed and scored with a Gingival Inflammatory Index (modified Gingival Index, Löe and Silness, 1963) using the follow ing criteria:
by K E N N E T H L . K A L K W A R F , D.D.S., M.S.* SEVERAL STUDIES have observed a relationship between altered levels of sex hormones and variations in degree of gingival inflammation. Earlier works " observed in creased gingival inflammation in females during preg nancy. The rise in inflammation closely paralleled an increase in the blood level of the hormones estrogen and progesterone seen during pregnancy. Since the gingival inflammation and the hormone levels subsided following parturition, it was suggested that altered levels of estro gen and progesterone may influence the inflammatory state. Several investigations " studied the effect of hor monal application on soft tissue inflammation in ani mals. Each found that hormonal application resulted in vascular and connective tissue changes. Hugoson longitudinally studied a group of pregnant women and investigated hormone influence on gingival healing. From this work he hypothesized that the aggra vation of gingivitis seen during pregnancy was caused primarily by an elevated level of progesterone and its effect on the microvascular system. ElAttar recently discovered that addition of sex hor mones to gingival tissue caused a significant increase in the synthesis of prostaglandin E . Since E-type prosta glandins are potent mediators of inflammation, expla nation of the mechanism by which sex hormones increase inflammation may be possible. Oral contraceptives have become a very widely used form of birth control during the past two decades. Since all oral contraceptives act by artificially altering sex hormone levels, their influence on gingival inflammation has been studied. Lindhe and Bjorn showed a significant increase of gingival fluid in individuals taking oral contraceptives. This was later supported by Grower et al. Lynn and Kaufman each described an episode of hyperplastic gingivitis that was related to ingestion of oral contraceptives. El-Ashiry ' found females taking oral contraceptives revealed states of gingival inflammation very similar to pregnant individuals. Knight and Wade found no statistically significant differences between plaque scores, gingival scores or losses of attachment when individuals taking oral con 1
5
4
12
13
0 = Clinically normal gingiva 1 = Mild inflammation with no bleeding on gentle manipulation of the sulcus with a probe 2 = Moderate inflammation with bleeding upon gentle manipulation of the sulcus 3 = Severe inflammation with sulcular ulceration and spontaneous bleeding upon gentle manipu lation Following recording of the Gingival Inflammatory Index, a two-tone disclosing solution† was applied to the teeth and the same reference areas were evaluated for debris using the following criteria:
14
2
15
0 = No disclosable material present at the gingival margin 1 = A pink film present at the gingival margin 2 = A moderate accumulation of dark pink or blue staining material present at the marginal area 3 = An abundance of blue to purple staining material present at the gingival margin
16
17
18
19 20
Following the completion of the clinical examination, the patient was asked to complete a questionnaire cov ering the following areas: 1. Current usage of oral contraceptives. If the patient
21
* Department of Periodontology, College of Dentistry, University of Nebraska—Lincoln, Lincoln, Neb 68583.
† Dis-plaque® (Pacemaker Corporation, Portland, Oregon) 560
Volume 49 Number 11
Oral Contraceptive
was currently taking oral contraceptives, the brand name and the time period they had been taking the present brand was recorded. 2. Total accumulative months they had taken oral contraceptives throughout their lives. 3. Any other medications they were currently taking or had taken for more than 2 continuous weeks within the past year. 4. Any systemic diseases or conditions, such as preg nancy, that presently existed. Of the 189 patients, 18 were eliminated from the study because of medications or systemic conditions which may have had an influence upon their gingival tissues. Three individuals were eliminated from the study be cause of discontinuance of oral contraceptive therapy within the past 8 weeks. Following dismissal of the patient, a mean Oral Debris Index and a mean Gingival Inflammatory Index were compiled and the data obtained were submitted to sta tistical analysis. The study was divided into three sections: Part I. Current Use of Oral Contraceptives Group A—Yes Group B—No (Control) Part II. Brand of Oral Contraceptive Currently Being Taken Group B—None (Control) Group C—Ovulen Group D—Norinyl 1 + 50 Group E—Norlestrin Group F—Demulen Group G—Ovral Group H—Norinyl 1 + 80 Group I—Ortho-Novum 1/80 Group J—Ortho-Novum 1/50 Group K—Oracon Group L—Enovid-E Part III. Total Accumulated Exposure to Oral Con traceptives Group M—No exposure (Control) Group N—1-11 months Group O—12-35 months Group P—36 or more months Each member of each group met the original criteria for patient selection. No attempt was made to match individuals between the groups. A mean Oral Debris Index and a mean Gingival Inflammatory Index was compiled for each group. Within each part of the study, a pooled variance estimate compared the mean indices of each group with every other group. RESULTS
Part I . When all individuals presently taking oral contracep tives were pooled and compared to the group not cur rently taking oral contraceptives, the following observa tions were evident (Table 1):
Therapy
561
1. The group currently taking oral contraceptives pos sessed a higher Gingival Inflammatory Index (P < 0.001). 2. The group taking oral contraceptives possessed a lower Oral Debris Index (P < 0.04). Part I I . The 93 individuals taking oral contraceptives were divided into groups (Table 2). Three of these groups were not considered for individual statistical analysis. The Norlestrin (E) and Enovid-E (L) groups consisted of too few members to be conclusive. The Oracon group (K) was not evaluated because it was a sequential-type contraceptive and since has been removed from the market by the United States Federal Drug Administra tion. The majority of the oral contraceptives consisted of 1.0 mg of progestin compound and 50 to 80 meg of estrogen. The notable exceptions were Ovulen which contained 100 meg of estrogen and Ovral which con tained 0.5 mg of progestin. Norinyl 1 + 50 (D) and Ovral (G) demonstrated a statistically significant lower Oral Debris Index at the 5% level of confidence or better when compared with the group that was not taking oral contraceptives. Ovulen (C), Ovral (G) and Norinyl 1/80 (I) revealed a signifi cantly higher Gingival Inflammatory Index at the 5% level of confidence or better when compared with a group that was not taking oral contraceptives. TABLE 1. Comparison of Individuals Currently Taking Oral Contracep tives With Individuals Not Taking O r a l Contraceptives
Control
Group
N
I.I. x ± SE
x±SE
A B
93 75
1.49 (0.04) 1.20 (0.05) ( P < 0.001)
0.81 (0.10) 0.95 (0.04) (P < 0.04)
D.I.
N = Number of subjects. I.I. = Gingival Inflammatory Index. D.I. = Oral Debris Index. SE = Standard error of the mean. TABLE 2. Hormone Content, Gingival Inflammatory Index and Oral Debris Index of Each B r a n d of O r a l Contraceptive Group
N
B C D E F G H I J K L
75 25 8 3 6 14 11 9 9 5 2
Estro Progestin gen (meg)
Control
100 50 50 50 50 80 80 50 100 100
I.I.
(mg)
x ± SE
1.0 1.0 1.0 1.0 0.5 1.0 1.0 1.0 25.0 2.5
1.20 (0.05) 1.47 (0.10) 1.18(0.18) 1.70 (0.46) 1.57 (0.08) 1.49 (0.12) 1.68 (0.12) 1.49 (0.11) 1.44 (0.20) 1.60 (0.14) 1.15 (0.15)
N = Number of subjects. I.I. = Gingival Inflammatory Index. D.I. = Oral Debris Index. SE = Standard error of the mean.
D.I. x±SE 0.95 0.84 0.58 1.20 0.82 0.71 1.00 0.72 0.80 0.84 0.65
(0.05) (0.09) (0.10) (0.56) (0.12) (0.10) (0.15) (0.13) (0.13) (0.16) (0.35)
562
J. Periodontol. November, 1978
Kalkwarf
No significant differences were found in either Oral Debris or Gingival Inflammatory Indices when compar isons between other groups were made. The two oral contraceptive groups having different hormonal compositions (Ovulen with increased estrogen and Ovral with decreased progesterone) revealed very similar effects when compared to the group not taking oral contraceptives. Ovulen showed an increased mean Gingival Inflammatory Index that was significant at the 0.02 level. Ovral exhibited a decreased mean Oral Debris Index, significant at the 0.05 level and an elevated mean Gingival Inflammatory Index, significant at the 0.04 level.
results. While several numerical differences were found to be statistically significant, a clinical or biological difference between some groups may be questionable. Statistical differences found in this study confirm pre vious findings " ' that gingival inflammatory indices are higher for individuals taking oral contraceptives than in subjects not taking such medication. Previous work has shown that this is probably due to the effects of artificially elevated levels of progesterone. Increased pro gesterone levels have been shown to alter microvascular topography and permeability of gingival tissues, ' increase the number of polymorphonuclear leucocytes within the gingival sulcus ' and, in combination with estradiol, increase synthesis of prostaglandin E in gingival tissue. Each of these mechanisms could be responsible for causing an exaggerated gingival inflammatory response to a local irritant. Thus, a persistent accumulation of bacterial plaque at the gingival margin capable of caus ing a low grade inflammation for a female not taking oral contraceptives could produce an exaggerated re sponse if the individual were artificially increasing sys temic progesterone levels by taking oral contraceptives. Clinically, this phenomenon could be important. A low grade "pregnancy gingivitis" could be the result of bac terial plaque accumulation and systematically altered progesterone levels from intake of oral contraceptives. The important difference is that while hormone alter ation is over in a maximum of 9 months with the pregnant individuals; individuals taking oral contracep tives may be altering their hormone levels for much longer periods of time. The Gingival Inflammatory Index used in this study is a slight modification of the Gingival Index introduced by Löe and Silness in 1963. A few of the visual criteria were eliminated in an attempt to eliminate subjectivity. The differences found in gingival inflammatory indi ces between various brands of oral contraceptives were interesting, but not conclusive. A l l brands of oral contra ceptives encountered except one (Ovral) consisted of 1 mg of progestin compound. The progestin was either norethindrone, ethynodiol diacetate or norethynodrel. Ovral contained 0.5 mg of norgestrel and was one of the brands that individually demonstrated a significantly higher Gingival Inflammatory Index when compared to the control group. Each brand consisted of 50, 80 or 100 meg of estrogen compound. The estrogen was either ethinyl estradiol or mestranol. The three groups individually exhibiting sig nificantly higher Gingival Inflammatory Indices (Ovu len, Ovral and Norinyl 1 + 80) consisted of 100 meg of mestranol, 50 meg of ethinyl estradiol and 80 meg of mestranol respectively. The term Oral Debris Index was used in this study rather than Plaque Index. A two-tone disclosing solu tion was applied at the gingival margin of each refer ence area with a cotton swab. The patient was then allowed to rinse once with two ounces of tap water. A l l 15
17 20
6 912
1013
22
2
P a r t III. Mean Oral Debris Indices and mean Gingival Inflam matory Indices of groups with different total accumula tive exposure to oral contraceptives (Table 4) were not statistically different. Sixty-four percent of the individ uals in this study had an accumulative exposure of less than 36 months to oral contraceptives. DISCUSSION
One must be careful in analysis of data from a crosssectional study such as this one. It must be assumed that indices for inflammation and oral debris taken at four line angles (two posterior and two anterior) are repre sentative for that particular patient. Because of several factors (oral hygiene habits, tooth position, etc.) these areas may not be representative for all patients. It must be considered also that factors other than oral debris contribute to clinical gingival inflammation. Sys temic factors, many of which perhaps are nonmeasurable at the present time, may play a role in the severity of gingival inflammation recorded. It is reasonable to assume that selecting the entire sample size from a group that meets selected criteria, distributes these uncontrollable variables. One must be careful also in analysis of the statistical TABLE 3. O r a l Contraceptive M e a n Gingival Inflammatory
Brands Exhibiting Significantly Indices or Mean Oral Debris
Different Indices
Oral Debris Index
Gingival Inflammatory Index C>B(P B ( P < 0.04) H > B (P < 0.002)
D
