1. Journal of Dental Research
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Evaluation of New Gingival Retraction Agents
W.H. Bowles, S.J. Tardy and A. Vahadi
J DENT RES 1991 70: 1447
DOI: 10.1177/00220345910700111101
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2. Evaluation of New Gingival Retraction Agents
W.H. BOWLES, S.J. TARDY, and A. VAHADI
Department of Biochemistry, Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, Texas 75246
Current gingival retraction agents are not without undesirable shrinkage of the tissues. Alum acts mainly as an astringent and is
side-effects; there appears to be no ideal gingival retraction agent. considered to be safe and moderately effective as a tissue-displacing
Several sympathomimetic amines, capable of producing local vaso- agent. Dental supply catalogs are extremely vague about the
constriction with minimal systemic side-effects, are available as concentration of chemical agents, frequently failing even to specify
non-prescription nasal decongestants and eye washes. The purpose the active ingredient.
ofthis study was to evaluate the efficacy of three ofthese agents for Epinephrine, either supplied as a separate solution or incorpo-
gingival tissue displacement. rated into the string, has been widely used. In many patients,
Mongrel dogs were used as experimental subjects, in which however, epinephrine produces a syndrome of undesirable side-
pulse rate and blood pressure were monitored electronically. Visine® effects (Donovan et al., 1985; Benson et al., 1986) that may include
(tetrahydrozoline HCl, 0.05%), Afrin® (oxymetazoline, 0. 05%), and tachycardia, increased respiratory rate, hypertension, nervous-
Neosynephrine® (phenylephrine HCl, 0.25%) were the commercial ness, feelings of weakness in the extremities, frank apprehension,
products studied as gingival retraction agents. Plain, untreated and post-operative depression. General anesthesia is sometimes
cord was used as a mechanical control, and as a vehicle for the three used for full-mouth reconstruction and other extended dental pro-
experimental agents. Commercially available cords impregnated cedures. General anesthetics of the fluorinated-hydrocarbon type,
with both racemic epinephrine (8%) and alum were also used as such as halothane, sensitize the myocardium to epinephrine and
standard retraction agents with which the test solutions were may produce life-threatening reactions (Price and Dripps, 1965).
compared. Thus, care should be taken that epinephrine-containing retraction
Visine and Afrin produced tissue displacement greater than that cord not be used for restorative procedures when halothane or other
of any of the other agents; Neosynephrine, epinephrine, and alum fluorinated-hydrocarbon general anesthetics are used.
were more effective than the untreated mechanical control. Cardio- Chemical agents used in gingival retraction have recently been
vascular changes included a slight increase in systolic pressure in reviewed by Nemetz and Seibly (1990). There appears to be no ideal
the Neosynephrine group, and a slightly lower mean arterial pres- agent for gingival retraction, and therefore, it is considered worth-
sure and pulse rate in all three experimental groups. while for new agents for this purpose to be explored. There are
several vaso-active substances which, when used topically, have
J Dent Res 70(11):1447-1449, November, 1991 relatively few side-effects. These substances are the active ingredi-
ents in various over-the-counter (non-prescription) nasal or oph-
Introduction. thalmic decongestants: tetrahydrozoline HCl, 0.05% (Visine®);
oxymetazoline HCl, 0.05% (Afring); and phenylephrine HCl, 0.25%
Advertising by dentists, coupled with public service announce- (Neosynephrine®). They are all classified as sympathomimetic
ments sponsored by various dental organizations, have led to a amines and act as alpha-agonists. Local vasoconstrictor actions are
greater public awareness of the value and availability of cosmetic most prominent, with minimal systemic effects (Cutting, 1969).
dentistry and, hence, a greater demand for these services. Prepara- Apparently, none ofthese agents has been previously examined
tion of teeth for these restorations frequently includes the identifi- as a potential gingival retraction agent. The present studies were
cation of a subgingival margin or finish line. In order for a undertaken to examine the effectiveness and safety of these three
satisfactory impression to be obtained, tissue displacement or compounds (tetrahydrozoline, oxymetazoline, and phenylephrine)
gingival retraction is necessary. as gingival retraction agents, and to compare their effects with those
According to Benson et al. (1986), gingival retraction measures ofcords impregnated with epinephrine and with alum. Preliminary
fall into one of four major categories: (1) simple mechanical meth- reports have appeared in abstract form (Tardy and Bowles, 1989;
ods, (2) chemo-mechanical methods, (3) rotary gingival curettage, Vahadi and Bowles, 1990).
and (4) electro-surgical methods. Of these four categories, the
chemo-mechanical method of gingival retraction is the most widely
used, as was found in a survey by Donovan et al. (1985). The Materials and methods.
mechanical aspect ofthis method involves placement of a string into Commercially available solutions of the three test agents were
the gingival sulcus to displace the tissues physically. The chemical used in the form of Visine® (tetrahydrozoline hydrochloride,
aspect of the method involves treatment of the string with one or 0.05%), Afrin® (oxymetazoline hydrochloride, 0.05%), and
more of a number of compounds that will induce temporary shrink- Neosynephrine®(phenylephrine hydrochloride, 0.25%). These three
age ofthe tissues and should also control the hemorrhage and fluid agents, incorporated into commercially available untreated cord
seepage that often accompany subgingival margin preparation. (Retrax®, Pascal), were compared with commercially prepared
Substances most often used are: racemic epinephrine, 0.1% solution cords containing 8% racemic epinephrine (Racord®, Pascal), and
or 8% impregnated cord; alum; aluminum chloride, 5% or 25%; ferric with alum (Pascord®, Pascal). Untreated cord was used as a
sulfate, 13.3%; or zinc chloride, 8% or 40%. Aluminum chloride and mechanical control.
zinc chloride are caustic to gingival tissues and thus are not Mongrel dogs were used as experimental subjects, with from two
recommended. Ferric sulfate acts as a clotting agent, and often, to five teeth per quadrant available, depending on the condition of
when the string is removed, the clot is pulled out with it, and the gingiva. Non-terminal use of dogs in this study was approved by
hemorrhage begins anew. Also, ferric sulfate does not cause actual the Animal Care Committee of the Baylor College of Dentistry.
Each dog was anesthetized with sodium pentobarbital, 30 mg/kg,
Received for publication August 13, 1990 i.v. A pediatric or neo-natal blood pressure cuff placed around one
Accepted for publication June 26, 1991 ofthe dog's hind legs, with leads attached to a DynaMap® electronic
This investigation was supported in part by Baylor College of Dentistry monitor, was found to be suitable for monitoring both pulse rate and
Student Pre-doctoral Fellowships #SP-887 and #S-8913. blood pressure. This eliminated the need for arterial cannulation,
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1447

3. 1448 BOWLES et al. J Dent Res November 1991
thus reducing trauma to the dog. Each tooth to be used was marked TABLE 1
at the gingival crest with a small bur in a high-speed handpiece. A
preliminary impression was made by use of an Accu-Gel® syringe COMPARISON OF THE EFFECTS OF VARIOUS GINGIVAL
and tray impression material, with a custom acrylic tray, and the RETRACTION AGENTS ON SULCUS WIDTH
cast was poured with improved laboratory stone. The teeth selected
for the study were isolated and the retraction medium placed: Group n Mean Width (mm) ± S.D.
commercially available, untreated cord as a mechanical control, or
commercially prepared cord impregnated with either epinephrine Control 6 0.38 ± 0.07
(8%) or saturated alum, or plain cord pre-saturated with one of the
test solutions. All cords used, both plain and treated, were from the Alum 8 0.49 ± 0.02a
same manufacturer; they were all the same size, and all were of the
twisted type. For the sake of consistency, the packing of the Epinephrine 5 0.51 ± 0.04a
retraction cord was performed by only one individual. The cords Neosynephrine 6 0.58 ± 0.09b
were removed after five min, and a second impression was made.
Casts were made and compared with the pre-treatment casts. Afrin 6 0.80 ± 0.09c
Sections of the casts were sawed out, and the teeth under investiga-
tion were sectioned bucco-lingually at the buccal eminence, followed Visine 6 0.84 ± 0.09d
by quantitative measurement of the width of the retracted sulcus, Significantly differentfrom: acontrols(p < 0.01); bcontrols(p < 0.005);
under a low-power microscope equipped with a 0.25-mm grid. The call other groups except Visine (p < 0.001); and dall other groups
width was measured as the distance from the tooth to the crest of the except Afrin (p < 0.001).
gingiva. After ten days, the tissues of the dogs' mouths were re-
examined for evidence of recession by comparison ofthe crest of the
gingiva with the original mark. significantly lower in the Visine® and Afrin® groups than in the
The techniques used in this study are standard procedures that epinephrine group. The pulse rate of the epinephrine group was
have been used to evaluate most of the gingival retraction agents elevated significantly above that of controls, while that of the
that are currently in clinical use (Woychesin, 1964). Neosynephrine® and Afrin® groups was significantly lower. All
three alpha-agonist groups had a pulse rate significantly lower than
Results. that in the epinephrine group.
Statistical analysis of the data included analysis of variance, Discussion.
followed by ScheffM's test for multiple comparisons of unequal
sample sizes. The depth ofthe gingival sulcus was not significantly The use of the DynaMap electronic monitor provided a conve-
affected by any of the test agents. The mean width of the gingival nient means for non-invasive monitoring of the cardiovascular
sulcus of each group is shown in Table 1. Analysis of variance responses in the dogs during treatment.
showed significant differences among the experimental groups (F Many clinicians appear to be concerned about possible side-
ratio = 39.4, p < 0.001). The mean widths (± S.D.) of the retracted effects from the epinephrine-impregnated retraction cord. Alterna-
sulcus in the Visine® (0.84 ±0.09 mm) andAfrin® (0.80 ±0.09 mm) tive agents include solutions ofzinc, aluminum, or iron salts, which
groups were not significantly different from each other, but were are often caustic to the gingiva. This study suggests that a number
significantly wider than those of all of the other groups (p < 0.001). of sympathomimetic amines, currently available as non-prescrip-
The width of the retracted sulcus of the Neosynephrineg (0.58 ± tion items for other local applications, may provide safer and more
0.09 mm) was significantly greater (p < 0.005) than that of the effective alternatives to those agents currently in use. Visine® and
controls (0.38 ±0.07 mm); the sulcus widths ofthe epinephrine (0.51 Afrin® have similar active ingredients (imidazole derivatives) and
±0.04 mm) and alum (0.49 ±0.02 mm) groups were also significantly appear to be similarly more effective than epinephrine or
greater than that of the control group (p < 0.01), but not signifi- Neosynephrine® (a phenylethylamine derivative, similar to epi-
cantly different from each other, nor were they significantly differ- nephrine).
ent from those of the Neosynephrine® group (p . 0.05). Examina- A gingival retraction agent should be (1) effective for its intended
tion of the dogs' mouths after ten days revealed no permanent use, (2) safe-both locally and systemically, and (3) the effects
gingival depression as a result of treatment with the experimental should be spontaneously reversible, wearing off in a short time,
agents. leaving no permanent tissue displacement. The three agents tested
In this study, because of the difficulty in standardizing the appear to meet these criteria when used in the appropriate quanti-
process, no deliberate effort was made to induce gingival bleeding in ties. Scarcely any drug is completely free of side-effects, and
order to evaluate the abilities of the test agents to control hemor- package inserts accompanying these products list a number of
rhage. However, in some cases, a slight amount of hemorrhage was possible side-effects that may occur if used repeatedly, over an
induced by the packing of the cord. It was noted that, in those cases, extended period oftime. It should be noted, however, that use of any
the test agents all appeared to be quite effective in controlling the of these agents as a gingival retractant requires only the use of an
seepage. amount equal to one application as an eye wash or as a nasal
Some differences were noted in the cardiovascular responses of decongestant (two drops), and is not repeated at frequent intervals,
the dogs during application of the various test agents (Table 2). as one might do with an eye wash or nasal decongestant. Thus, there
Systolic pressure was elevated by the application of epinephrine, is little or no chance of an overdose in this application. The
Neosynephrine®, and Afrin®, but only with Neosynephrine® was possibility of an allergic reaction exists for patients who may be
the difference statistically significant. In the Neosynephrine® and sensitized to the product. As is prudent with any type of medication,
Afrin® groups, the systolic pressure was also significantly higher careful questioning of the patient as to prior use and any untoward
than in the Visine® group. No significant differences in diastolic reactions should minimize the risk of such an event. A preliminary
pressure were noted among the various groups. The mean arterial clinical trial with a small number of patients has been reported by
pressure was the same in the control and epinephrine groups, while Tardy et al. (1990), in which Visine® was compared with epine-
it was actually significantly lower in each of the alpha-agonist phrine as a gingival retractant. In that study, Visine® was shown
groups than in the controls. The mean arterial pressure was also to produce approximately 50% greater tissue displacement and
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4. Vol. 70 No. 1 1 NEW GINGJVAL RETRACTION AGENTS 1449
TABLE 2
COMPARISON OF CARDIOVASCULAR EFFECTS OF EPINEPHRINE AND NEW POTENTIAL GINGIVAL RETRACTION AGENTS
MEAN SD
Group (n) Mean Arterial
Systolic Pressure Diastolic Pressure Pulse Pressure Pulse Rate
Control (5) 104.2 ± 6.5 48.0 ± 6.0 75.6 ± 1.5 99.4 ± 2.6
Alum (8) 103.4 ± 5.7 48.3 ± 5.2 75.6 ± 2.7 100.3 ± 2.7
Epinephrine (5) 107.6 ± 6.6 48.6 ± 4.5 75.4 ± 3.9 *107.6 ± 2.3
Visine (5) 104.8 ± 3.2 41.8 ± 6.1 *"57.6 ± 3.4 "96.0 ± 1.7
Neosynephrine (7) '*125.3 ± 6.9 40.0 ± 4.7 '*66.3 ± 6.0 *"92.9 ± 3.3
Afrin (5) '111.8 ± 3.1 45.2 ± 10.0 *"61.2 ± 2.6 *"92.8 ± 0.98
* Significantly different from controls (p < 0.001).
Significantly different from epinephrine (p < 0.001).
Significantly different from Visine (p < 0.001).
slightly better control ofcrevicular seepage, with no detectable side- Volatile Anesthetics: Diethyl Ether, Divinyl Ether, Chloroform,
effects. The results of this study and of the preliminary human Halothane, Methoxyflurane, and other Halogenated Volatile Anesthet-
study show superior tissue displacement compared with that of ics. In: The Pharmacological Basis of Therapeutics, 3rd ed., L.S.
gingival retractants in current clinical use, and, therefore, these Goodman and A. Gilman, Eds., New York: The Macmillan Company, p.
agents warrant a full clinical trial. 93.
TARDY, S.J. and BOWLES, W.H. (1989): Evaluation of New Gingival
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