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An evaluation of the drugs used for gingival retraction
AN EVALUATION OF THE DRUGS USED FOR GINGIVAL RETRACTION
F. WOYCHESHIN,
FELIX
The University
D.D.S."
of Texas Dental
Branch,
Houston,
Texas
ELASTIC IMPRESSION MATERIALS such as the hydrocolloids and the rubber base impression materials, used in the construction of inlays, crowns, and bridges, do not displace the gingival tissues and necessitate gingival retraction to expose the gingival margins of the cavity preparations. Various methods of gingival retraction have been described in the literature.iv2 The most conservative and widely used method consists of placing a cotton cord or cotton fibers which have been impregnated with a drug into the gingival crevice; another method is that of placing a cord and then applying the drug. These cords and drugs are left in the gingival crevice for varying lengths of time, depending upon the drug used and the condition of the gingival tissues. Various drugs have been used for gingival retraction, but no comparative study of the efficiency or undesirable characteristics of the drugs has been reported in the literature. This is a report of such a study, using dogs as the experimental subjects. The study was done in two parts. The first part was concerned with the relative ability of the drugs to retract the gingival tissues and local tissue injury, and the second part was concerned with systemic reactions. Ideally, in a study to evaluate the efficiency of drugs to retract the gingival tissues, the conditions of the gingivae and depth of the gingival crevice should be the samefor each drug tested. The sulcus around most of the teeth in dogs is very shallow, but the buccal sulcus of cuspids and first molars is from 2 to 3 mm. deep. Therefore, we chose to use the buccal sulcus of only these eight teeth in each dog.
T
HE
EXPERIMENTAL OF GINGIVAL
PROCEDURE
FOR COMPARING
EFFICIENCY
RETRACTION
Average-sized dogs were selected for the study without consideration of their oral health. The dogs were anesthetized by the intravenous administration of 30 mg. per kilogram of body weight of pentobarbital sodium. Read before the American Academy *Associate Professor of Restorative
of Crown Dentistry 769
and Bridge Prosthodontics (Fixed Crown and Bridge
in Chicago. Prosthesis).
J. Pros. Den. July-Aug., 1964
WOYCHESHIN
Fig.
1.
Fig. l.- Casts produced from gingival tissues with agent D. Fig. 2.-Casts produced from gingival tissues with agent G.
Fig.
Fig. made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
3.
Fig. 3.-Casts produced from gingival tissues with agent C. Fig. 4.-Casts produced from gingival tissues with agent K.
2.
impressions
Fig.
4.
The teeth were isolated and a groove was cut with a knife-edge diamond revolving instrument on the buccal surface of each tooth at the level of the free gingiva, following the contour of the free gingiva accurately from the mesial to the distal surface. A polysulfide rubber impression was made in a custom acrylic resin tray of each of the teeth and a Hydrocal stone cast was made. Each tooth was isolated again and the gingival tissue was retracted by placing either a plain cord or a cord impregnated or saturated with a solution of a drug into the gingival crevice. The cotton cords used were of uniform thickness, and the cord was placed with care so that the epithelial attachments would not be disturbed and the tissue not be stripped by instrumentation. The cord was removed immediately before each impression was made with polysulfide rubber and a Hydrocal stone cast was made in the resulting impression. Thirteen agents were used, and a designation was given to each (Table I).
DRUGS
TABLE AGENT __-.-.
I3 c D FE
f L” M
GINCIVAL
771
RETRACTION
I. THE RETRACTION AGENTS STUDIED
-..-.
A
ifi
FOR
Alum (saturated solution) Cocaine (10 ye plus epinephrine 1 :OOO) Hemodent gingival retraction cord (a cord impregnated with “hemodent” containing aluminum chloride, hydroxyquinoline sulfate, phenocainium chloride, and ethyl aminobenzoate Gingi-Pak (a cord impregnated with approximately 1 mg. of racemic epinephrine hydrochloride per inch) Gingi-Pak plus alum (saturated solution) Cord impregnated with 8% zinc chloride plus 8:lOO racemic epinephrine Monsel’s solution-solution of ferric subsulfate Negatan solution-an aqueous solution containing in 100 Gm. approximately 4.5 Gm. of a condensation product obtained by reacting meta-cresol sulfonic acid with formaldehyde Plain cotton cord Tannic acid (20%), full strength Zinc chloride (8%), a cord impregnated with 8% zinc chloride solution Zinc chloride (40%), a cord impregnated with 40% zinc chloride solution Racemic epinephrine 8:lOO.
Two rubber base impressions were made of each tooth and casts were poured. The first impression and cast registered the tooth with its groove cut at gingival level before retraction. The second impression registered the level of the gingival tissue in relation to the groove after gingival retraction. The amount of tissue retraction which could be attributed to the specific agent used was determined by comparing the first cast with the second cast, as illustrated in Figs. 1 through 4. The casts were compared and the relative effectiveness of the retracting agents used was determined by comparing all of the others to agent D, since agent D was the material used on every dog studied. Agent D was given an arbitrary value of 5.
Fig. 5.-The
in&al
two thirds of the crown of the central incisor on the left was placed
in a full strength solution of agent a similar manner with 10 per cent enamel of both teeth.
H for one hour, and the tooth solution of agent H. Note the
on the right was treated in severe decalcification of the
Fig. B.--Four cotton pellets containing 0.5 mg. of racemic epinephrine gingival tissue on the buccal surface of upper posterior teeth. The pellets lution. The systolic blood pressure rise in this case was equal to 120 mm. sure started to rise 50 seconds after application of the pellets, and reached
were saturated with 8:lOO racemic epinephrine and applied to lacerated were removed after 2 minutes and the area was irrigated with saline soHg and indicates systemic absorption of epinephrine. The blood presa maximum in 3 minutes.
Volume Number
14 4
DRUGS
FOR
GINGIVAL
RETRACTION
773
Retracting agents with greater effectiveness on the specific dog involved were given a higher rating-those with less effectiveness, a lower rating. NO retraction at all was rated as 0. The results are tabulated in Table II. To determine local tissue injury, the tissues were observed immediately after retraction, and the tissues were re-examined for gingival recession after 7 and 11 days. These observations are reported in Table II as “tissue recovery.” Agent H is highly acid and it is only natural to suspect that it decalcifies the teeth. This was clearly demonstrated by placing the crowns of extracted human teeth in both a full-strength solution and a 10 per cent solution of Agent H for one hour. The enamel was severely decalcified and etched (Fig. 5). Except in extremely rare hypersensitive individuals, epinephrine is the only drug among the drugs tested which one might expect would have the ability to produce systemic effects when applied topically to the gingival tissues. When a drug is applied locally to the gingival tissues there is a possibility that it may be absorbed.3 Because of its vasoconstrictive effects, the absorption of epinephrine when used locally would increase the arterial blood pressure and alter the heart rate. These effects could be dangerous in patients with cardiovascular disease. In susceptible dental patients, absorption of epinephrine could cause pallor, tremors, anxiety and nervousness, tachycardia and palpitation, and rise of blood pressure.4 Even in normal dental patients, the symptoms could be alarming. The purpose of this part of the investigation, therefore, was to determine, with the use of dogs as the ,experimental animals, whether there are changes in general systemic blood pressure and heart rate when very high conceptions of epinephrine are used to retract the gingival tissues. EXPERIMENTAL
PROCEDURES
TO DETERMINE
SYSTEMIC
EFFECT
The dogs were prepared according to the method described in The United States Phar%acopeia for the assay of epinephrine.5 Dogs of medium size were anesthetized by intravenous injection of 30 mg. per kilogram of body weight of
TABLE
DRUGS
USED
II.
NO. OF DOGS USED
EFFECTOF
DRUGSUSEDFORGINGIVAL
EFFECTIVENESS OF GINGIVAI. RETRACTION
RETRACTION
TISSUE RECOVERY
OTHER UNDESIRABLE CHARACTERISTICS
--____
Agent A Agent B Agent C Agent D Agent E Agent F Agent G Agent H Agent I Agent J Agent K Agent L Agent M ---.-___
-__
12 3 1.5 27
4.2s 2 5.4 5
d 4 3 8
h” 5.75 6 1
: 8 3
z.9 5.6 4.5
Good Good Good Fair Fair Fair Good Poor Good Good Fair Poor Fair .-.~-___
None __ None None None May cauterize tissue if left too long Messy Decalcifies tooth substance None None May cauterize tissue if left too long Cauterizes tissue None ..--
TABLE
J. Pros. July-Aug..
WOYCHESHIN
774 III.
EFFECTS OF 3 INCHES OF A GINGIVAL RACEMIC EPINEPHRINE PER INCH OF CORD TISSUESQFTHE
RETRACTION CORD CONTAINING APPLIED TO LACERATED GINGIVAL DOG
RISE INCREASE DOG No.
IN ~1.00~
54 24 12
7h ---
(MM.
OF
up)
IN HEART RATE SYSTOLIC
2 5
PRESSURE
1 hl~.
Den. 1964
36 18 12 42
8 2 34 2 4 0 16
DIASTOLIC
0 0 14 0 10 0 14
___--
pentobarbital sodium, and uniform anesthesia was maintained by small supplemental doses. The animals were arranged for the recording of systemic blood pressure and heart rate from the femoral artery with a Hathaway pressure transducer attached to a physiograph. A pneumograph was used to record the respiration. The physiograph produced continuous records of elapsed time, heart rate, blood pressure, and respiration; all injections and operations were noted directly on the record. A test dose of 10 mcg. per kilogram of body weight of a 0.01 per cent solution of acetylcholine was administered intravenously and the response was recorded. Atropine sulfate in the dose of 1 mg. per kilogram of body weight was administered intravenously so that subsequent intravenous injections of acetycholine failed to produce any decrease in blood pressure. Immediately after the vagal receptor mechanism was paralyzed, the retraction procedures were performed on the dogs in a manner which simulated gingival retraction procedures on patients in dental practice. Two concentrations of epinephrine were used. One of the preparations was a gingival retraction cord containing 1 mg. of racemic epinephrine hydrochloride per inch of cord, and the other preparation consisted of cotton pellets containing approximately 0.5 mg. of racemic epinephrine moistened with an 8 :lOO solution of racemic epinephrine. The cord preparation was used to retract the gingival tissues, and the cotton pellets saturated with 8 :lOO racemic epinephrine were used to control bleeding and to simulate control of gingival hemorrhage for impression making at the dental chair. The cord was applied first because its effects would have little influence upon the larger amounts of epinephrine contained in the cotton pellets. The applications of the cord were made to both the intact and lacerated tissues; the pellets moistened with the 8:lOO epinephrine solution were applied to lacerated tissue only. For the applications made to lacerated tissue, the free margin of the gingiva was lacerated with a revolving crosscut fissure bur. Therefore, the laceration simulated the gingival trauma sometimes produced during cavity preparations for crowns and inlays. The gingival tissue on the buccal surface of upper posterior teeth was re-
volume Number
14 ‘l
TABLE
DRCG.5 IV.
OF 4 COTTON
EFFECTS
MOISTENED
WITH
FOR
GINGIVAL
PELLETS
AN 8:lOO SOLUTION LACERATED GINGIVAL
RETRACTION
CONTAINING~.~ OF RACEMIC TISSUE
MG. OF RACEMIC EPINEPHRINE EPINEPHRINEAPPLIEDTO OFTHE DOG
RISE IN RLOOD INCREASEIN RATE
DOG NO.
775
PRESSURE
(MM.
Hg)
HEART
SYS1‘OLIC
I
DIASTOLIC
I
1
0
6 12 48 24 12 128 102
4 5
6 7
48 120 ii 152 140
2: 50 38 26 102 48 -___.-___
tracted by means of 3 inches of cord in each application, and the cord was left in the gingival crevice for 10 minutes. After the cord was removed, the area was irrigated to remove as much excess epinephrine as possible, and then the gingival tissue on the buccal surface of four posterior teeth on the opposite arch was lacerated. Four cotton pellets were moistened with the 8 :lOO epinephrine solution, placed in contact with the lacerated gingiva, and left in place for 2 minutes. After the pellets were removed, the area was irrigated with saline solution. EXPERIMENTAL
RESULTS
OF SYSTEMIC
EFFECTS
Control procedures using applications of saline, alum, zinc chloride, and Hemodent were performed. These had no effect on heart rate and blood pressure. When applied to the intact gingival tissues, the gingival retraction cord containing 1 mg. of racemic epinephrine per inch of cord also had no effect on the heart rate and blood pressure in the six experiments that were done. For the applications made to lacerated gingival tissues, experiments were done on 7 dogs using the gingival retraction cord containing 1 mg. of epinephrine per inch of cord in one quadrant. Later, the cotton pellets saturated with 8:lOO epinephrine solution were used in another quadrant. The results are given in Tables 111 and IV. The tables show that some of the applications of epinephrine to lacerated gingival tissue produced no change in blood pressure, but an example of a physiograph record which shows a rise in blood pressure is shown in Fig. 6. I)ISCUSSION
The effectiveness of gingival retraction of twelve drugs or combinations of drugs was evaluated. A plain cotton cord was used as a control. With the exception of agent B, all of the drugs or combinations of drugs tested were effective in shrinking the gingival tissues and, under normal conditions in the average dental patient, would expose the margins of cavity preparations sufficiently for elastic impression procedures. In difficult cases, or cases where more than the average amount of gingival retraction is required, those drugs or combinations of drugs
776
WOYCHESHIN
J. Pros. July-Aug.,
Den. 1964
which have a rating of 5 or above would be most effective. As shown in Table II, the combinations of epinephrine plus alum, and epinephrine plus zinc chloride were more effective than epinephrine, alum, or zinc chloride used alone. The tissue recovery was satisfactory with the use of all of the drugs except with the zinc chloride and negatan preparations. Zinc chloride (8 per cent) may be used satisfactorily without permanent tissue recession if the application is limited to 3 or 4 minutes. Zinc chloride (40 per cent) is very caustic and should be used only for conditions which require the removal of hypertrophied gingival tissue. Negatan is highly acid and is contradinicated because it decalcifies tooth substance. The systemic effects of topical applications of very high concentrations of epinephrine to the intact and lacerated gingival tissues of the dog were determined. No systemic effect was detected when 3 inches of a cord containing 1 mg. of epinephrine per inch was applied to the intact tissue, but when the same amount of the saturated cord was applied to lacerated gingival tissues, the absorption of epinephrine produced an increase in the heart rate in every instance, and a slight rise in blood pressure in some dogs. When larger amounts of epinephrine were applied with pellets to lacerated gingival tissues, the systemic response was much more severe, as shown by the greater increase in the heart rate and higher rise in blood pressure. The severity of the systemic response seems to vary among individuals, is dependent upon vascular exposure, and increases with an increase in the amount or concentration of epinephrine used. SUMMARY
1. Most of the drugs commonly used for gingival retraction are effective in shrinking the gingival tissues. 2. Zinc chloride is caustic and prolonged application or high concentrations will cauterize the tissue. 3. Negatan is highly acid and decalcifies the teeth. 4. When very high concentrations or amounts of epinephrine are applied locally to lacerated tissue, epinephrine can be absorbed and cause an increase in the heart rate and blood pressure, which could be dangerous for patients with cardiovascular disease, hyperthyrodism, and to certain hypersensitive individuals. 5. The application of high concentrations of epinephrine to large areas of lacerated or abraded gingival tissues should be avoided. REFERENCES
1. Tylman, 2. 3. 4. 5.
S. D., and Tylman,. S. G.: Theory and Practice of Crown and Bridge Prosthodontics, ed. 4, St. Louis, 1960, The C. V. Mosby Company, pp. 515-519. Thompson, M. J.: Exposing the Cavity Margin for Hydrocolloid Impressions, J. South California D. A. 19:17-24, 1951. Gogerty, J. H., Strand, H. A., Ogilvie, A. L., and Dille, J. M.: Vasopressor Effects of Topical Epinephrine in Certain Dental Procedures, Oral Surg., Oral Med., & Oral Path. 10:614-622, 1957. Sollmann, T.: A Manual of Pharmacology and Its Applications to Therapeutics and Toxicology, ed. 7, Philadelphia, 1948, W. B. Saunders Co., p. 372. The Pharmacopeia of the United States of America, ed. 14, Easton, Pa., 1950, Mack Publishing Co., pp. 214-216. P. 0. Box 20068 HOUSTON, TEXAS 77025
F. WOYCHESHIN,
FELIX
The University
D.D.S."
of Texas Dental
Branch,
Houston,
Texas
ELASTIC IMPRESSION MATERIALS such as the hydrocolloids and the rubber base impression materials, used in the construction of inlays, crowns, and bridges, do not displace the gingival tissues and necessitate gingival retraction to expose the gingival margins of the cavity preparations. Various methods of gingival retraction have been described in the literature.iv2 The most conservative and widely used method consists of placing a cotton cord or cotton fibers which have been impregnated with a drug into the gingival crevice; another method is that of placing a cord and then applying the drug. These cords and drugs are left in the gingival crevice for varying lengths of time, depending upon the drug used and the condition of the gingival tissues. Various drugs have been used for gingival retraction, but no comparative study of the efficiency or undesirable characteristics of the drugs has been reported in the literature. This is a report of such a study, using dogs as the experimental subjects. The study was done in two parts. The first part was concerned with the relative ability of the drugs to retract the gingival tissues and local tissue injury, and the second part was concerned with systemic reactions. Ideally, in a study to evaluate the efficiency of drugs to retract the gingival tissues, the conditions of the gingivae and depth of the gingival crevice should be the samefor each drug tested. The sulcus around most of the teeth in dogs is very shallow, but the buccal sulcus of cuspids and first molars is from 2 to 3 mm. deep. Therefore, we chose to use the buccal sulcus of only these eight teeth in each dog.
T
HE
EXPERIMENTAL OF GINGIVAL
PROCEDURE
FOR COMPARING
EFFICIENCY
RETRACTION
Average-sized dogs were selected for the study without consideration of their oral health. The dogs were anesthetized by the intravenous administration of 30 mg. per kilogram of body weight of pentobarbital sodium. Read before the American Academy *Associate Professor of Restorative
of Crown Dentistry 769
and Bridge Prosthodontics (Fixed Crown and Bridge
in Chicago. Prosthesis).
J. Pros. Den. July-Aug., 1964
WOYCHESHIN
Fig.
1.
Fig. l.- Casts produced from gingival tissues with agent D. Fig. 2.-Casts produced from gingival tissues with agent G.
Fig.
Fig. made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
impressions
made
before
and
after
retraction
of the
buccal
3.
Fig. 3.-Casts produced from gingival tissues with agent C. Fig. 4.-Casts produced from gingival tissues with agent K.
2.
impressions
Fig.
4.
The teeth were isolated and a groove was cut with a knife-edge diamond revolving instrument on the buccal surface of each tooth at the level of the free gingiva, following the contour of the free gingiva accurately from the mesial to the distal surface. A polysulfide rubber impression was made in a custom acrylic resin tray of each of the teeth and a Hydrocal stone cast was made. Each tooth was isolated again and the gingival tissue was retracted by placing either a plain cord or a cord impregnated or saturated with a solution of a drug into the gingival crevice. The cotton cords used were of uniform thickness, and the cord was placed with care so that the epithelial attachments would not be disturbed and the tissue not be stripped by instrumentation. The cord was removed immediately before each impression was made with polysulfide rubber and a Hydrocal stone cast was made in the resulting impression. Thirteen agents were used, and a designation was given to each (Table I).
DRUGS
TABLE AGENT __-.-.
I3 c D FE
f L” M
GINCIVAL
771
RETRACTION
I. THE RETRACTION AGENTS STUDIED
-..-.
A
ifi
FOR
Alum (saturated solution) Cocaine (10 ye plus epinephrine 1 :OOO) Hemodent gingival retraction cord (a cord impregnated with “hemodent” containing aluminum chloride, hydroxyquinoline sulfate, phenocainium chloride, and ethyl aminobenzoate Gingi-Pak (a cord impregnated with approximately 1 mg. of racemic epinephrine hydrochloride per inch) Gingi-Pak plus alum (saturated solution) Cord impregnated with 8% zinc chloride plus 8:lOO racemic epinephrine Monsel’s solution-solution of ferric subsulfate Negatan solution-an aqueous solution containing in 100 Gm. approximately 4.5 Gm. of a condensation product obtained by reacting meta-cresol sulfonic acid with formaldehyde Plain cotton cord Tannic acid (20%), full strength Zinc chloride (8%), a cord impregnated with 8% zinc chloride solution Zinc chloride (40%), a cord impregnated with 40% zinc chloride solution Racemic epinephrine 8:lOO.
Two rubber base impressions were made of each tooth and casts were poured. The first impression and cast registered the tooth with its groove cut at gingival level before retraction. The second impression registered the level of the gingival tissue in relation to the groove after gingival retraction. The amount of tissue retraction which could be attributed to the specific agent used was determined by comparing the first cast with the second cast, as illustrated in Figs. 1 through 4. The casts were compared and the relative effectiveness of the retracting agents used was determined by comparing all of the others to agent D, since agent D was the material used on every dog studied. Agent D was given an arbitrary value of 5.
Fig. 5.-The
in&al
two thirds of the crown of the central incisor on the left was placed
in a full strength solution of agent a similar manner with 10 per cent enamel of both teeth.
H for one hour, and the tooth solution of agent H. Note the
on the right was treated in severe decalcification of the
Fig. B.--Four cotton pellets containing 0.5 mg. of racemic epinephrine gingival tissue on the buccal surface of upper posterior teeth. The pellets lution. The systolic blood pressure rise in this case was equal to 120 mm. sure started to rise 50 seconds after application of the pellets, and reached
were saturated with 8:lOO racemic epinephrine and applied to lacerated were removed after 2 minutes and the area was irrigated with saline soHg and indicates systemic absorption of epinephrine. The blood presa maximum in 3 minutes.
Volume Number
14 4
DRUGS
FOR
GINGIVAL
RETRACTION
773
Retracting agents with greater effectiveness on the specific dog involved were given a higher rating-those with less effectiveness, a lower rating. NO retraction at all was rated as 0. The results are tabulated in Table II. To determine local tissue injury, the tissues were observed immediately after retraction, and the tissues were re-examined for gingival recession after 7 and 11 days. These observations are reported in Table II as “tissue recovery.” Agent H is highly acid and it is only natural to suspect that it decalcifies the teeth. This was clearly demonstrated by placing the crowns of extracted human teeth in both a full-strength solution and a 10 per cent solution of Agent H for one hour. The enamel was severely decalcified and etched (Fig. 5). Except in extremely rare hypersensitive individuals, epinephrine is the only drug among the drugs tested which one might expect would have the ability to produce systemic effects when applied topically to the gingival tissues. When a drug is applied locally to the gingival tissues there is a possibility that it may be absorbed.3 Because of its vasoconstrictive effects, the absorption of epinephrine when used locally would increase the arterial blood pressure and alter the heart rate. These effects could be dangerous in patients with cardiovascular disease. In susceptible dental patients, absorption of epinephrine could cause pallor, tremors, anxiety and nervousness, tachycardia and palpitation, and rise of blood pressure.4 Even in normal dental patients, the symptoms could be alarming. The purpose of this part of the investigation, therefore, was to determine, with the use of dogs as the ,experimental animals, whether there are changes in general systemic blood pressure and heart rate when very high conceptions of epinephrine are used to retract the gingival tissues. EXPERIMENTAL
PROCEDURES
TO DETERMINE
SYSTEMIC
EFFECT
The dogs were prepared according to the method described in The United States Phar%acopeia for the assay of epinephrine.5 Dogs of medium size were anesthetized by intravenous injection of 30 mg. per kilogram of body weight of
TABLE
DRUGS
USED
II.
NO. OF DOGS USED
EFFECTOF
DRUGSUSEDFORGINGIVAL
EFFECTIVENESS OF GINGIVAI. RETRACTION
RETRACTION
TISSUE RECOVERY
OTHER UNDESIRABLE CHARACTERISTICS
--____
Agent A Agent B Agent C Agent D Agent E Agent F Agent G Agent H Agent I Agent J Agent K Agent L Agent M ---.-___
-__
12 3 1.5 27
4.2s 2 5.4 5
d 4 3 8
h” 5.75 6 1
: 8 3
z.9 5.6 4.5
Good Good Good Fair Fair Fair Good Poor Good Good Fair Poor Fair .-.~-___
None __ None None None May cauterize tissue if left too long Messy Decalcifies tooth substance None None May cauterize tissue if left too long Cauterizes tissue None ..--
TABLE
J. Pros. July-Aug..
WOYCHESHIN
774 III.
EFFECTS OF 3 INCHES OF A GINGIVAL RACEMIC EPINEPHRINE PER INCH OF CORD TISSUESQFTHE
RETRACTION CORD CONTAINING APPLIED TO LACERATED GINGIVAL DOG
RISE INCREASE DOG No.
IN ~1.00~
54 24 12
7h ---
(MM.
OF
up)
IN HEART RATE SYSTOLIC
2 5
PRESSURE
1 hl~.
Den. 1964
36 18 12 42
8 2 34 2 4 0 16
DIASTOLIC
0 0 14 0 10 0 14
___--
pentobarbital sodium, and uniform anesthesia was maintained by small supplemental doses. The animals were arranged for the recording of systemic blood pressure and heart rate from the femoral artery with a Hathaway pressure transducer attached to a physiograph. A pneumograph was used to record the respiration. The physiograph produced continuous records of elapsed time, heart rate, blood pressure, and respiration; all injections and operations were noted directly on the record. A test dose of 10 mcg. per kilogram of body weight of a 0.01 per cent solution of acetylcholine was administered intravenously and the response was recorded. Atropine sulfate in the dose of 1 mg. per kilogram of body weight was administered intravenously so that subsequent intravenous injections of acetycholine failed to produce any decrease in blood pressure. Immediately after the vagal receptor mechanism was paralyzed, the retraction procedures were performed on the dogs in a manner which simulated gingival retraction procedures on patients in dental practice. Two concentrations of epinephrine were used. One of the preparations was a gingival retraction cord containing 1 mg. of racemic epinephrine hydrochloride per inch of cord, and the other preparation consisted of cotton pellets containing approximately 0.5 mg. of racemic epinephrine moistened with an 8 :lOO solution of racemic epinephrine. The cord preparation was used to retract the gingival tissues, and the cotton pellets saturated with 8 :lOO racemic epinephrine were used to control bleeding and to simulate control of gingival hemorrhage for impression making at the dental chair. The cord was applied first because its effects would have little influence upon the larger amounts of epinephrine contained in the cotton pellets. The applications of the cord were made to both the intact and lacerated tissues; the pellets moistened with the 8:lOO epinephrine solution were applied to lacerated tissue only. For the applications made to lacerated tissue, the free margin of the gingiva was lacerated with a revolving crosscut fissure bur. Therefore, the laceration simulated the gingival trauma sometimes produced during cavity preparations for crowns and inlays. The gingival tissue on the buccal surface of upper posterior teeth was re-
volume Number
14 ‘l
TABLE
DRCG.5 IV.
OF 4 COTTON
EFFECTS
MOISTENED
WITH
FOR
GINGIVAL
PELLETS
AN 8:lOO SOLUTION LACERATED GINGIVAL
RETRACTION
CONTAINING~.~ OF RACEMIC TISSUE
MG. OF RACEMIC EPINEPHRINE EPINEPHRINEAPPLIEDTO OFTHE DOG
RISE IN RLOOD INCREASEIN RATE
DOG NO.
775
PRESSURE
(MM.
Hg)
HEART
SYS1‘OLIC
I
DIASTOLIC
I
1
0
6 12 48 24 12 128 102
4 5
6 7
48 120 ii 152 140
2: 50 38 26 102 48 -___.-___
tracted by means of 3 inches of cord in each application, and the cord was left in the gingival crevice for 10 minutes. After the cord was removed, the area was irrigated to remove as much excess epinephrine as possible, and then the gingival tissue on the buccal surface of four posterior teeth on the opposite arch was lacerated. Four cotton pellets were moistened with the 8 :lOO epinephrine solution, placed in contact with the lacerated gingiva, and left in place for 2 minutes. After the pellets were removed, the area was irrigated with saline solution. EXPERIMENTAL
RESULTS
OF SYSTEMIC
EFFECTS
Control procedures using applications of saline, alum, zinc chloride, and Hemodent were performed. These had no effect on heart rate and blood pressure. When applied to the intact gingival tissues, the gingival retraction cord containing 1 mg. of racemic epinephrine per inch of cord also had no effect on the heart rate and blood pressure in the six experiments that were done. For the applications made to lacerated gingival tissues, experiments were done on 7 dogs using the gingival retraction cord containing 1 mg. of epinephrine per inch of cord in one quadrant. Later, the cotton pellets saturated with 8:lOO epinephrine solution were used in another quadrant. The results are given in Tables 111 and IV. The tables show that some of the applications of epinephrine to lacerated gingival tissue produced no change in blood pressure, but an example of a physiograph record which shows a rise in blood pressure is shown in Fig. 6. I)ISCUSSION
The effectiveness of gingival retraction of twelve drugs or combinations of drugs was evaluated. A plain cotton cord was used as a control. With the exception of agent B, all of the drugs or combinations of drugs tested were effective in shrinking the gingival tissues and, under normal conditions in the average dental patient, would expose the margins of cavity preparations sufficiently for elastic impression procedures. In difficult cases, or cases where more than the average amount of gingival retraction is required, those drugs or combinations of drugs
776
WOYCHESHIN
J. Pros. July-Aug.,
Den. 1964
which have a rating of 5 or above would be most effective. As shown in Table II, the combinations of epinephrine plus alum, and epinephrine plus zinc chloride were more effective than epinephrine, alum, or zinc chloride used alone. The tissue recovery was satisfactory with the use of all of the drugs except with the zinc chloride and negatan preparations. Zinc chloride (8 per cent) may be used satisfactorily without permanent tissue recession if the application is limited to 3 or 4 minutes. Zinc chloride (40 per cent) is very caustic and should be used only for conditions which require the removal of hypertrophied gingival tissue. Negatan is highly acid and is contradinicated because it decalcifies tooth substance. The systemic effects of topical applications of very high concentrations of epinephrine to the intact and lacerated gingival tissues of the dog were determined. No systemic effect was detected when 3 inches of a cord containing 1 mg. of epinephrine per inch was applied to the intact tissue, but when the same amount of the saturated cord was applied to lacerated gingival tissues, the absorption of epinephrine produced an increase in the heart rate in every instance, and a slight rise in blood pressure in some dogs. When larger amounts of epinephrine were applied with pellets to lacerated gingival tissues, the systemic response was much more severe, as shown by the greater increase in the heart rate and higher rise in blood pressure. The severity of the systemic response seems to vary among individuals, is dependent upon vascular exposure, and increases with an increase in the amount or concentration of epinephrine used. SUMMARY
1. Most of the drugs commonly used for gingival retraction are effective in shrinking the gingival tissues. 2. Zinc chloride is caustic and prolonged application or high concentrations will cauterize the tissue. 3. Negatan is highly acid and decalcifies the teeth. 4. When very high concentrations or amounts of epinephrine are applied locally to lacerated tissue, epinephrine can be absorbed and cause an increase in the heart rate and blood pressure, which could be dangerous for patients with cardiovascular disease, hyperthyrodism, and to certain hypersensitive individuals. 5. The application of high concentrations of epinephrine to large areas of lacerated or abraded gingival tissues should be avoided. REFERENCES
1. Tylman, 2. 3. 4. 5.
S. D., and Tylman,. S. G.: Theory and Practice of Crown and Bridge Prosthodontics, ed. 4, St. Louis, 1960, The C. V. Mosby Company, pp. 515-519. Thompson, M. J.: Exposing the Cavity Margin for Hydrocolloid Impressions, J. South California D. A. 19:17-24, 1951. Gogerty, J. H., Strand, H. A., Ogilvie, A. L., and Dille, J. M.: Vasopressor Effects of Topical Epinephrine in Certain Dental Procedures, Oral Surg., Oral Med., & Oral Path. 10:614-622, 1957. Sollmann, T.: A Manual of Pharmacology and Its Applications to Therapeutics and Toxicology, ed. 7, Philadelphia, 1948, W. B. Saunders Co., p. 372. The Pharmacopeia of the United States of America, ed. 14, Easton, Pa., 1950, Mack Publishing Co., pp. 214-216. P. 0. Box 20068 HOUSTON, TEXAS 77025