Sahar Asaad Sabbak, BDS, MSc. Hanaa Mohammed Al-Elshaikh, BDS, MSc
Department of Restorative Dental Sciences, College of Dentistry, King Saud University, PO Box 5967, Riyadh 11432, Saudi Arabia

An accurate final impression for fixed prosthodontics requires careful management of the soft tissue. Various methods and medicaments have been described in the literature to create an acceptable environment for making an impression. This survey study was designed to find out the frequency of using different methods and medicaments for gingival displacement by prosthodontists and general practitioners in the different areas in the Kingdom of Saudi Arabia. A questionnaire was formulated and distributed among dentists in the target population. Responses from two hundred and thirty-two prosthodontists and general practitioners were included in this study. The results indicated that a majority of the respondents use the mechanico-chemical method of gingival displacement and most of those respondents use aluminum chloride medicament. It was also found that there is no statistically significant relationship between the medicament used and the degree, institution and year of graduation of the respondents from the dental schools.

An impression or negative likeness of the teeth and surrounding structures is used to obtain a cast on which the restoration is then made. A good impression is an exact negative replica of each prepared tooth and must include all of the prepared surfaces as well as an adequate amount of unprepared tooth structure adjacent to the margin. Therefore, a gingival tissue displacement may be needed to obtain an access to the prepared tooth. This may involve the use of mechanical, mechanico- chemical, surgical (that includes gingival and periodontal surgery, electrosurgery and rotary gingival curettage) or combination of two or more of these methods, any of which may produce an adverse local or systemic response. The mechanical method of gingival displacement was among the first developed. This method involves physical displacement of the gingival tissue by placement of materials within the gingival sulcus. Several types of materials may be used like the rubber dam, ' plain cotton thread, unwaxed floss ' and untreated surgical silk. The use of copper bands,⁶ acrylic resin copings, temporary aluminum shells, temporary polycarbonate crown shells, cotton twills rolled in a creamy mixture of zinc oxide and eugenol cement, leather and elastic rings was also documented. Non-medicated retraction cords is the most conservative mechanical method of gingival displacement.' ' '

In the mechanico-chemical method, cords, strings or cotton pellets are used to keep homeostatic chemical agents in contact with the gingival tissues and confine them to the application site. The homeostatic chemical agents can be either vasoconstrictors like epinephrine '" or astringents like aluminum chloride, aluminum potassium sulfate (alum), aluminum sulfate,  ferric subsulfate (Monsel solution), ferric sulfate, Negatol solution (Negatan),' tannic acid,'  chloride zinc and combination of any of  these agents.

Questionnaires were sent to dentists in different areas in the Kingdom of Saudi Arabia (Table 1). In this study, responses from prosthodontists and general practitioners were considered. Respondents were asked to indicate their degree, institution and year of graduation.

The percentage of respondents who routinely check medical condition was found to be 53.9% (Table 2). 2.6% of the respondents indicated that they never check the medical condition with 43.5% occasionally checking it. On the other hand, majority of respondents check pulse rate and blood pressure occasionally (57.8%). A little over than thirty-three percent of the respondents check it routinely with 9.0% who never check it.

At all years of graduation the highest frequency and percentage of respondents [184(83.64%)] prefer mechanico-chemical method of gingival displacement as their first choice (Table 3). As the year of graduation becomes more recent, there is an increase in the frequency of respondents using different gingival displacement methods. The percentage of respondents using the mechanico-chemical method increases as the graduation year goes from 1960 to 1996. As the graduation year goes from 1970 to 1996, there is a decrease in the percentage of those using the mechanical method. At the same period, the percentage of respondents who prefer to use the surgical technique of gingival displacement remains almost similar. Combination of methods is preferred by only 3.70% and 4.69% respondents who graduated in 1970-1979 and 1980-1989 periods, respectively.

As the year of graduation becomes more recent, there is an increase in the frequency of respondents using different medicaments in gingival displacement as shown in Table 4. All respondents who graduated in the period 1950-1969 use medicaments in gingival displacement. This percentage decreases to 71.43% as the graduation year moves from 1970-1979 period after which it increases again. The chi-square analysis demonstrated no significant relationship between the used medicament and the year of graduation (X²= 4.828, P= 0.089).

As the year of graduation becomes more recent, there is a higher frequency but a lower percentage of respondents using epinephrine in gingival displacement (Table 5). The highest frequency and percentage of respondents [108 (46.96%)], regardless of year of graduation, use aluminum chloride. The frequency and percentage of respondents using aluminum chloride is increased as the graduation year becomes more recent. The highest percentage of respondents using potassium aluminum sulfate (10.45%) is found in the 1980-1989 period. Ferric sulfate was found to be used by 33.33% respondents who graduated in 1960-1969. This percentage is decreased then increased again in 1990-199 , period for 15.0%. Tannic acid is used by 4.17% and ^48% respondents who graduated in 1970-1979 and 1980-1989, respectively. Only 3.57% of graduated respondents in 1990-1996 use tannic acid. A combination of tannic acid. A combination of medicaments is used by 1.49% respondents who graduated in 1980-1989. Other solutions are used by 4.48% respondents who graduated in the same period.

The highest frequency and percentage of respondents [188 (83.56%)] with different degrees prefer to use the mechanico-chemical method of gingival displacement (Table 6). Higher percentages of respondents with MS/PhD degrees prefer to use the mechanical, surgical and combination of methods than those with BDS degrees. The total frequency and percentage of respondents with a BDS degree using different methods of gingival displacement [173 (76.89%)] are more than those respondents with MS/PhD degree [52 (23.11%)].

A high frequency and percentage of respondents with BDS and MS/PhD [195(85.53%)] degrees use medicaments (Table 7). A higher frequency and a slightly lower percentage of respondents with a BDS degree 150 (85.23%) use medicaments than those with MS/PhD degree of 45 (86.54%). The chi-square analysis demonstrated no significant relationship between the used medicament and degree (X² = 0.00014, P = 0.991).

The highest frequency and percentage of respondents [109 (46.58)], with different degrees, use aluminum chloride (Table 8).

Epinephrine is used by respondents with BDS degree (24.02%) less than by those with MS/PhD degree (41.82%). Majority of respondents with BDS degree use aluminum chloride (50.28%), while most of those with MS/PhD degree use epinephrine (41.82%). Aluminum chloride and potassium aluminum sulfate are more used by respondents with BD" degree (50.28% and 6.70%, respectively) than those with MS/PhD degree (34.55% and 5.45%, respectively). Ferric sulfate is used by a higher percentage of respondents with MS/ PhD degree (14.55%) than that of respondents with BDS degree (12.85%). Tannic acid is not used by respondents with MS/PhD degree, but by those with BDS degree (5.03%). More than one percent of the respondents with MS/PhD degrees use a combination of medicaments, while BDS degree holders do not use it. Other solutions are used by 1.12 % and 1.82 % of respondents with BDS and Ms/PhD degrees, respectively.

Table 9 shows a higher frequency and percentage of respondents who graduated from K.S.A. (Kingdom of Saudi Arabia) institutions [141(62.39%)] than those who graduated from institutions other than K.S.A. [85(37.61)]. The highest frequency and percentage of respondents (189(83.63%) prefer to use the mechanico- chemical method of gingival displacement. Those respondents who graduated from K.S.A. institutions have a higher frequency and percentage [124(87.94%)] than others [65(76.47%)]. The percentages of respondents, who graduated from K.S.A. institutions, who prefer to use mechanical surgical and combination of methods are less than those who graduated from other institutions.

Table 10 shows that respondents who graduated from K.S.A. and other institutions prefer to use different medicaments (88.65% and 80.68%, respectively) constituting 196 (85.59%) of the total frequency of respondents. More respondents who graduated from K.S.A. institutions use medicament (88.65%) than those who graduated from other institutions (80.68%). The chi-square analysis demonstrated no significant relationship between the use of medicaments and the institution of graduation (X² = 2.182, P = 0.140).

The highest frequency and percentage of respondents [110 (46.61%)], regardless of institution of graduation, prefer to use aluminum chloride (Table 11). The highest percentage of respondents who graduated from K.S.A. institutions prefer to use aluminum chloride (56.86%) followed by epinephrine (18.30%), ferric sulfate (15.03%), potassium aluminum sulfate (4.58%), tannic acid (3.92%) then combination of medicaments and other solutions (0.65%). Epinephrine and aluminum chloride are preferred to be used by higher frequencies and percentages of respondents who graduated from institutions other than K.S.A. 39 (46.99%) and 23 (27.71%), respectively. Equal frequencies and percentages of respondents who graduated from those institutions use potassium aluminum sulfate and ferric sulfate 8 (9.64%). Tannic acid is used by 3.61% of those who graduated from institutions other than K.S.A. In general, percentage of respondents, who graduated from K.S.A. institutions, using aluminum chloride, ferric sulfate and combination of medicaments are more than those respondents who graduated from other institutions.

In Table 12, 78.78% of respondents use ephinephrine in a concentration of equal to or less than 2%. It is also used by 12.12% of respondents in a concentration of 3-5% solutions. More than six percent of respon- dents use it in a concentration of 8% and 3.03% of them use it in 10-15% concentra- tions. Aluminum chloride is used in equal to or less than 5% by 37.03% of respondents. 33.34% of them use it in a concentration of 15-20%. Only 3.7% of respondents use 8 - 10% aluminum chloride. It is also used by 16.66% respondents in concentrations of 21.3 - 25%. More than nine percent use it in a concentration of 30 - 35%. Potassium alumnium sulfate is used by 66.66% and 33.33% respondents in concentrations of 2% and 8%, respectively. Ferric sulfate is used by 57.14% respondents in a concentration of 15 - 15.5% while 23.81% respondents use it in less than 5% solution. Only 4.76% of the respondents use it in 20 - 21% concentration. At a concentration of 30-35%, it is used by 14.28% of respondents. Tannic acid is used by 50% of the respondents in a concentration of 10% while the other 50% use it in a concentration of 15-20%.

Table 13 shows the majority of respondents (45.47% and 40.9%) use epinephrine for less than 5 and 5-7 minutes, respectively. Only 1.52% use it for 16-18 minutes. Regarding aluminum chloride, 44.14% of respondents were found using it for 5-7 minutes while 3.6% of them use it for 13-15 minutes. Majority of the respondents (80%) use potassium aluminum sulfate for less than 5 minutes and 51.62% and 44.44% of them were found using ferric sulfate and tannic acid, respectively for 5-7 minutes.

In this study, only 3.4% of respondents had patients complaining of systemic manifestations as a result of gingival displacement. These included increased pulse rate, increased blood pressure, palpitation and rarely syncope. There was no report of cardiac arrest as a result of the procedure. Majority of respondents (96.7%) had no patients experiencing any systemic symptoms. Only 0.9% of respondents did not give any information.

It was found that 50.9% of respondents wet the retraction cord before removal from the gingival sulcus, while 47.8% do not. Respondents who failed to indicate any preference were 1.3%.
 

Identification of the medical condition of the patient is considered critical. Inappropriate identification, through improper history taking and interpretation, can create ineffective or even detrimental oral health care treatment and probable fatal systemic reaction. The results of this survey indicate that 53.9% of respondents check the medical condition of the patients routinely, 43.5% check it occasionally and only 2.6% never check it. Donovan et al (1985) reported a high percentage of respondents (98.18%) checking the medical history of the patients.

Dentists must assess vital signs including blood pressure, pulse, respiration and temperature. The dentist must also consider the environmental effects of the dental office on blood pressure and realize that an elevated blood pressure may not be indicative of an organic disease. In this survey, a higher percentage of respondents (33.2%) record the pulse rate and blood pressure routinely than those reported by Donovan et al '³ (1985) (3.03% checked the pulse rate and 8.48% checked the blood pressure).

In this study, majority of respondents (approximately 83.6%), with different institutions, degrees and years of graduation, prefer to use the mechanico- chemical method of gingival displacement. This was also reported by Donovan et al'³ (1985). Shaw and Krejci¹² (1986), on the other hand, reported much lower values. They reported 33% and 24% of surveyed dentists selecting the mechanico-chemical method of gingival displacement as their first and second method of choice, respectively. In the present study, as the year of graduation becomes more recent, more respondents use this method. This could be due to the marketing and availability of different medicaments more than before. This also reflects the increased use of medicaments in dental schools. In this study, the total percentages of respondents who prefer to use the mechanical method of gingival displacement (10.91%, 11.11% and 11.06% in Tables 3,6 and 9, respectively) are higher than that reported by Shaw and Krejci (1986) as first and second method of choice (7% and 6%, respectively). On the other hand, Donovan et al'³ (1985) reported 16.97% dentists using plain cords in gingival displacement. The total percentages of respondents preferring to use the surgical method of gingival displacement (3.64%, 3.56% and 3.54%) are slightly higher than that reported by Shaw and Krejci ^,2 (1986) (2%) as the first choice (in the form of electrosurgery), but they are much lower than that of dentists choosing it as the second choice (17%).

In this study, the total percentage of respondents who prefer to use epinephrine in gingival displacement (28.26%, 28.21% and 29.39% in Tables 5, 8 and 11) are much lower than that of respondents choosing it as their first choice (55%), but higher than that of those choosing it as their second choice (20%). Donovan et al (1985) reported a much higher percentage of respondents using epinephrine (79.3%). In the present study, as the year of graduation becomes more recent, there is a decline in the preference of using epinephrine in gingival displacement. More prosthodontists (41.82%) prefer to use epinephrine than general practitioners (24.02%). The percentage of respondents, who graduated from a Kingdom of Saudi Arabia (K.S.A.) institution, using epinephrine (18.30%) is much lower than that of respondents who graduated from institutions other than K.S.A. (46.99%). Regional differences may explain this reduction, but other factors may be involved.

Moreover, aluminum chloride is preferred to be used by many respondents for gingival displacement more than any other medicament in this study. Donovan et al'³ (1985) reported only 19.39% of dentists using aluminum chloride. In the present study, aluminum chloride is preferred more by respondents with a Bachelor (BDS) degree and more by those who graduated from a K.S.A. institution. Its use increases as the graduation year becomes more recent. This could be due to the increased level of awareness of the side-effects of epinephrine.

This study also reveals that potassium aluminum sulfate is used by respondents less than ferric sulfate. This could be due to the fact that ferric sulfate produces gingival displacement after a relatively shorter application time of 1-3 minutes. The resulting tissue displacement is maintained for at least 30 minutes, so that repeating is seldom necessary for multiple impressions. Tissue healing is also rapid.

Tannic acid is used by respondents less than other chemicals. This could be due to the fact that it has a minimum effectiveness as a gingival displacement agent.

In the present study, there is no statistically significant relationship between the used medicaments and the year, degree and institution of graduation.

Different strengths of epinephrine are used in gingival displacement. These are 0.1%, 2%, 4%, 6%, 16% and 32%. Although the most commonly used one is 8%, ⁴ only 6.06% of respondents in the present study use it in the same concentration. Other authors recommended the use of the 4% epinephrine. In this study, 12.12% of respondents use it in 3-5% solutions. Most of respondents (78.78%) use it in a concentration of equal to or less than 2%.

Aluminum chloride solutions are available in concentrations of 5%, 10%, 15%, 20%, 21.3% and 25%.^,J5,23 Concentrations of 5% and 10% were reported to be safe and effective for gingival displacement. However, other studies reported local tissue destruction with concentrations of 10% and 15%. In this study, 37.03% of respondents use aluminum chloride in equal to or less than 5%, while 33.34% of them use it in 15- 20% solutions. The 25% solution was advocated for use with other chemical agents because it approximately doubled the homeostatic success of the other chemical used.'⁷ In this study, only 16.66% of respondents use it in 21.3-25% solutions. Some respondents (9.26%) use it in 30- 35% solutions.

Potassium aluminum sulfate (Alum) is used in concentrations of 10% and 100% for gingival displacement.' In this study, most of respondents (66.66%) use it in a concentration of 2% while 33.33% use it in 8% solution. Ferric sulfate is used as a gingival retraction agent in a concentration of 13.3%. ' Other concentrations of 15.5%, 20% and 21% were also reported.⁴¹⁵'⁹ In this study, most of respondents (57.14%) use ferric sulfate in concentrations of 15-15.5%, while only 4.76% use it in a concentration of 21%. Tannic acid is used in 20% and 100% concentrations.²⁴ Some authors suggest to use it in 15-25% concentrations.² In the present study, 50% of respondents use it in a concentration of 10% and the other 50% use it in 15-20% concentrations.

The reported application time of epinephrine varies from 5 to 15 minutes.²⁵ In this study, 45.49% of respondents use it for less than 5 minutes, while 40.91% use it for 5-7 minutes. Some respondents (12.12%) use it for 8-10 minutes. Only 1.52% of them use it for 16-18 minutes. A 10-minute application time of aluminum chloride in the sulcus is usually sufficient.' In this study, most of respondents (44.14%) use it for 5-7 minutes, while 23.12% of them use it for 8-10 minutes and 28.83% use it for less than 5 minutes. Only 3.6% of respondents use it for 13-15 minutes. Potassium aluminum sulfate has been recommended to be used for 10 minutes.'⁶ In the present study, most of respondents (80%) use it for less than 5 minutes, 13.33% of them use for 5-7 minutes and only 6.67% of respondents use it for 8-10 minutes. The recommended application time of ferric sulfate is 1 to 3 minutes, but can be used for 10 to 20 minutes.' In this study, 51.62% of respondents use it for 5-7 minutes, 25.81% of them use it for 8-10 minutes and 22.59% of them use it for less than 5 minutes. Tannic acid is used for 10 minutes.' In the present study, 22.22% of respondents use it for 8-10 minutes. Most of respondents (44.44%) use it for 5-7 minutes, while 33.33% of them use it for less than 5 minutes.

In this study, the low percent of respondents (3.4%) reporting adverse systemic reactions as a result of gingival displacement procedures could be due to the decline in using epinephrine. This may be due to the awareness of its systemic side-effects. Furthermore, the increased number of reports in the dental literature on the potential reaction to the use of epinephrine products is an additional contributing factor. Donovan et al '³ (1985) reported a much higher percent of dentists (20%) who reported patients that experienced some systemic manifestations to gingival displacement procedures. On the other hand, Shaw and Krejci '² (1986) reported that 25%, 20%, 14% and 5% of respondents who chose electrosurgery, epinephrine cord, other mechanical aids and astringent cord, respectively, observed adverse reactions.

Removing a dry cord from the gingival crevice can cause injury to the delicate epithelial lining.⁵ In this study, only 50.9% of respondents wet the gingival retraction cord before removal from the gingival sulcus. Donovan et al '³ (1985) reported a much lower percentage of respondents (33.94%) wetting the cords before removal from the gingival sulcus.
 

Based on the results of this survey study, the following conclusions can be drawn:

The authors are thankful to Dr. Nazeer Khan, Bio-Statistician, for his valuable help in the statistical analysis of data.