Evaluation additional retention, the dentist may be forced
of gingival retraction with ? – Adrenomimetic agents: An in-vivo study.
clinically evaluate the efficacy of Naphazoline as a gingival retraction agent
and compare it with Aluminium Chloride and Tetrahydrozoline.
15 subjects were
divided into 4 groups based on chemical gingival retraction agents used
Group 1: Control
(without gingival retraction)
impressions were made with irreversible hydrocolloid for all subjects for
central incisor. Retraction was done with Aluminium Chloride, Tetrahydrozoline
and Naphazoline in all the subjects with a wash out period of 7 days.
Impressions were poured with die stone. Casts were retrieved and sections were
made with a die cutter. Thin slices were obtained. Each slice was used to measure
the amount of retraction under stereomicroscope and images were transferred to an
Results: Statistical analysis was performed. Among
the three displacement agents tested, displacement cord with Naphazoline showed
the maximum displacement.
The marginal integrity is one of the most basic
criteria of the principles of tooth preparation. (1) The placement of margin or
finish line in relation to the gingival margin has a direct bearing on
fabrication of restoration and health of the periodontal tissue of the prepared
teeth. For esthetics, caries, existing restoration and need for additional
retention, the dentist may be forced to place the margins subgingivally.
Gingival retraction plays an important role during
impression making especially when the margins are placed subgingivally. It is a
procedure that involves the displacement of marginal soft tissues around a
tooth, mainly to allow proper access in preparation, precise impression taking
and cementation procedures. It allows the impression material to flow apical to
the subgingival finish line thereby registering it and an area apical to it. 2
Several methods for adequate gingival displacement have been
advocated which includes mechanical displacement, chemico?mechanical
displacement, electrosurgery, and rotary gingival curettage 3, 4 The
chemico?mechanical method is most widely used and employs retraction cord dipped in various chemical agents.5,6 The
retraction cord mechanically displaces the gingival tissue and absorbs moisture
contamination in the gingival sulcus, while the chemical agents control haemorrhage
and shrink the gingival tissues. Substances most often used are: Racemic Epinephrine,
0.1% solution or 8% impregnated cord; Alum; Aluminium Chloride, 5% or25%;
Ferric Sulfate, 13.3%; or Zinc Chloride, 8% or 40%. Aluminium chloride and Zinc
Chloride are caustic to gingival tissues and also interfere with the setting of
impression materials. Ferric Sulfate acts as a clotting agent, and often results
in discolouration of teeth. The astringent compounds are chemically stable and
active only at acidic pH which causes etching of the hard tooth tissues and
postoperative sensitivity of vital teeth and are also harmful to the gingival
fibroblasts. (7, 8)
Epinephrine, either supplied as a separate solution
or incorporated into the string, has been widely used. In many patients,
however, epinephrine produces a syndrome of undesirable side effects (9, 10)
that may include tachycardia, increased respiratory rate, hypertension,
nervousness, and feelings of weakness in the extremities, frank apprehension,
and post-operative depression.
The search for an ideal gingival retraction agent
continues. There are several vaso-active substances which, when used topically,
have relatively few side-effects. These substances are the active ingredients
in various over-the-counter (non-prescription) nasal or ophthalmic
decongestants: Tetrahydrozoline HCl, Oxymetazoline HCl, and Naphazoline .They
are all classified as sympathomimetic amines and act as alpha-agonists. Local
vasoconstrictor actions are most prominent, with minimal systemic effects and
less harmful to human tissues. (11) Though, Tetrahydrozoline and Oxymetazoline
have been studied, Naphazoline has not been studied for use as gingival
Hence the objective of
this study is to compare and evaluate the gingival displacement produced by Naphazoline
with Aluminium Chloride and Tetrahydrozoline.
MATERIALS AND METHODS
The study was approved
by the Ethical Committee of Army College of Dental Sciences, Secunderabad. Fifteen participants having healthy
periodontium and within age group of 18 to 30 years were included in the study.
Participants with anterior malocclusion, gingival recession, pregnant and
lactating, orthodontic treatment, allergic to Tetrahydrozoline, Aluminium
Chloride and Naphazoline were excluded from the study. Written informed consent
and impression making
The maxillary right central
incisor was selected and isolated. The schedule for gingival displacement and
impression making followed an intermittent gap of 7days, i.e. the impressions
with different chemical agents was repeated in the same patient after 7 days.
Hence, 4 impressions were made for a single patient
Group I: Baseline
Group II: Aluminium chloride
Group III: Tetrahydrozoline
Group IV: Naphazoline.
Group I: Baseline
were made for the control group in which no gingival displacement was done. The
impressions were made using addition silicone impression material. Impressions
were made and removed from participant’s mouth after the material was set. The
impressions were made; they were disinfected with 2% Glutaraldehyde solution.
Group II: Aluminium
Isolation was done on
maxillary right central incisor with cotton rolls to maintain dry working area.
The required dimension of the retraction cord was selected. Retraction cord
impregnated with Aluminium Chloride was looped around the labial surface of the
tooth and gently pushed into the sulcus with the gingival cord packer
instrument Figure 1. Retraction cord was removed after keeping for 10 min. Impressions
were made similar to the baseline impressions.
Group III: Tetrahydrozoline
recalled for evaluation of gingival health after 7 days. Same impression
procedure was repeated with Tetrahydrozoline solution and retraction cord of
same size and type. Impressions were made in a similar way as the baseline
Group IV: Naphazoline
displacement and impression
recalled for evaluation of gingival health after 7 days. Same impression procedure
was repeated with Naphazoline solution and retraction cord of same size and
type. Impressions were made in a similar way as the baseline impressions.
Pouring of impression
and sample preparation
Each of the four
impressions was poured immediately with die stone. Mesio?distal width of right
central incisor was measured with a Vernier calliper. Cast was positioned and
stabilized on the platform of a die cutter.
Primary cut was made on the mesial side of maxillary right central
incisor in the buccolingual direction through the entire length of the cast. (Fig
1a) A second cut was made distal to maxillary right central incisor along the
entire length of the cast and the incisor was separated from the cast (Fig 1 b)
Evaluation of the
amount of displacement
For determining the amount of displacement, each
sample was studied under a measuring stereomicroscope. Image was captured and
transferred to an image analyzer. Perpendicular line was drawn from the most
prominent point of the crest of marginal gingival to the incisal edge of
maxillary central incisor and the
gingival displacement was measured ( fig 1 (b) and fig 2). The values of
gingival displacement for all the specimens in µm are tabulated Table 1 and
subjected to statistical analysis.
Fig 1. Sectioning of cast
Fig 2. Showing Stereomicroscopic
image of measured gingival sulcus
was done using ONE WAY ANOVA Test graph 1 and Post- hoc test. According
to One way ANOVA there was significant difference between the control and
experimental groups. According to post hoc test, the difference amongst the
various experimental groups was not significant.
The results suggest
that all 3displacement agents produced statistically significant amount of
displacement. The mean (±standard deviation SD) of gingival displacement
achieved by four groups namely Control, Aluminium Chloride, Tetrahydrozoline
and Naphazoline is given in Table 1.
Table 1. Mean of gingival displacements of 4 groups.
The mean displacement
with Naphazoline is higher than the other two test groups although this is not
Graph 1. Graph showing
gingival displacement (µm)
WH Bowles et al in 1991
brought to light a new application for the nasal and eye decongestants
Oxymetazoline Hydrochloride, Xylometazoline Hydrochloride and Tetryahydrazoline.
The conclusion of his study was that Tetrahydrozoline showed great ability for
hemostasis and tissue retraction. (11)
classified as sympathomimetic amine and act as alpha-agonists. It is a vasoconstrictor
with rapid action and minimal systemic effects. It has been reported in the
previous studies that pH of Tetrahydrozoline is alkaline so causes less damage
to the gingival tissues and also to the tooth structure. It is safe to use Tetrahydrozoline
as gingival displacement. (12)
Hence in this study we
compared Naphazoline which is easily available over the counters with already
tested chemical Tetrahydrozoline and widely used aluminium chloride.
For impression making,
single step technique was used to avoid discrepancy that may creep in due to
the use of two materials, tray positioning and the time that elapses in the two
stage procedure between removal of the cord and the impression making. In the
present study, a method of pouring the impression of retracted gingival and measuring
displacement on the sectioned cast under stereomicroscope with an image
analyzer system was followed similar to the technique used by Bowles et al. (11)
retraction with one chemical agent the patient was recalled after a gap of 7
days. This was repeated with all the three chemical agents. According to a
study done by R Azzi et al in 1983, it was found that the gingival tissues take
around 7 days to heal after gingival retraction. (13)
effective reversible displacement of soft tissues with retraction cords presoaked
with ? – Adrenomimetic
agents. There was no significant difference found between Tetrahydrozoline, Naphazoline
and Aluminium Chloride. This can be attributed to ?- adrenergic activity resulting
in vasoconstriction comparable to astringents.
Any medicament used for
displacement should satisfy the following criteria; it must be effective, use
of medicament in a cord must result in sufficient displacement of the gingival
tissue to allow the dentist to make an adequate impression of gingival finish
line of the prepared tooth. It should not cause irreversible tissue damage
(tooth and gingiva) and harmful systemic effect. With respect to the criteria
mentioned above, displacement cord with Tetrahydrozoline and Naphazoline shows
excellent displacement, has negligible harm to tissue and has no potentially
harmful systemic effects. Hence, both ?-Adrenomimetic substances can be applied
successfully for the purposes of esthetic and restorative dentistry.
The conclusions that
were drawn from this study are:
displacement systems namely (Aluminum chloride, Tetrahydrozoline, Naphazoline)
show clinically and statistically significant amount of displacement.
Among the three
displacement agents tested, displacement cord with Naphazoline showed the
Considering the result
that displacement cord with the Naphazoline produces comparable displacement as
Aluminum Chloride, it can be a good alternative to it.
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