|Year : 2014 | Volume
| Issue : 4 | Page : 466-471
A comparative evaluation of propolis and 5.0% potassium nitrate as a dentine desensitizer: A clinical study
Aamir Rashid Purra1, Mubashir Mushtaq1, Shashi Rashmi Acharya2, Vidya Saraswati2
1 Department of Conservative Dentistry and Endodontics, Government Dental College and Hospital Srinagar, Kashmir, India
2 Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal, India
|Date of Submission||15-Sep-2013|
|Date of Acceptance||25-Dec-2013|
|Date of Web Publication||14-Aug-2014|
Aamir Rashid Purra
Department of Conservative Dentistry and Endodontics, Government Dental College and Hospital Srinagar, Kashmir
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: The purpose of this clinical study was to evaluate the efficacy of saturated ethanolic solution of Propolis for the treatment of dentin hypersensitivity. Materials and Methods: Ten patients aged 20-40 years with 156 hypersensitive teeth were selected for a 3-month study . Each patient was subjected to treatment with saturated ethanolic solution of Propolis, 5% potassium nitrate and distilled water. The patients were recalled at seventh day, 2 weeks and 4 weeks for the application of the agent and re-evaluation. The final re-evaluation of the patients was done after 3 months from the first application. The responses of the patients to the test temperatures were converted to a ranking and data was statistically analyzed. A statistical analysis was done using ANOVA and Bonferroni test and Tukey HSD test for multicomparison. Results: The results between the Propolis group and the potassium nitrate group showed no significant difference in the immediate post-treatment period; however, the results were significant at the end of first week and second week. At 4 weeks and 3 months period, a comparison between the groups again showed no significant difference. Conclusion: It was concluded that Propolis was more effective than 5% potassium nitrate in relieving dentinal hypersensitivity and had an immediate and sustained effect.
Keywords: Cold graded water test, distilled water, potassium nitrate, propolis
|How to cite this article:|
Purra AR, Mushtaq M, Acharya SR, Saraswati V. A comparative evaluation of propolis and 5.0% potassium nitrate as a dentine desensitizer: A clinical study. J Indian Soc Periodontol 2014;18:466-71
|How to cite this URL:|
Purra AR, Mushtaq M, Acharya SR, Saraswati V. A comparative evaluation of propolis and 5.0% potassium nitrate as a dentine desensitizer: A clinical study. J Indian Soc Periodontol [serial online] 2014 [cited 2019 Oct 18];18:466-71. Available from: http://www.jisponline.com/text.asp?2014/18/4/466/138695
| Introduction|| |
Dentin hypersensitivity is one of the most painful and least successfully treated chronic problems of the teeth. It is one of the common complaints and has been reported that as many as one in every seven patients undergoing dental treatment experiences this painful condition.  A wide array of treatment modalities is available for the management of dentin hypersensitivity. These modalities involve the application of various chemicals (desensitizing agents) such as potassium or ferric oxalates, potassium nitrate, stannous fluoride, sodium fluoride, sodium monofluorophosphate (MFP), strontium chloride, copal varnishes, calcium hydroxide, fluoride treatments, dentin bonding agents, or iontophoresis. The desensitizing agents are applied either by the dentist (in office treatment) or used by the patient as home application. Home applications are mainly in the form of dentifrices and also as mouthwashes. The effects of home-applied agents are manifested after a period of time and would require a considerable degree of patient compliance. In office treatment, modalities provide instantaneous relief to the patient, but the effects are often temporary. Thus, none of the treatment modalities has been able to provide a permanent relief from dentin hypersensitivity.
Potassium nitrate was introduced as a desensitizing agent by Hodosh.  It has been one of the widely prescribed desensitizing agents. It has been used in concentrations of 1%, 2%, 5%, 10%, and 15% or as a saturated solution. 5% is said to be most effective and is also incorporated into dentifrices.  Potassium nitrate is supposed to reduce hypersensitivity by inducing a sustained depolarization of nerve membrane as put forward by Pashlay.  It has also been postulated that blockage of dentinal tubules by potassium nitrate reduces sensitivity. 
Propolis is a resinous yellow brown to dark brown substance collected by honey bees from sprouts, exudates of trees and other parts of plants and modified in the beehives by addition of salivated secretions and wax. It is used by bees for protection, to repair openings and damages in hives, to construct aseptic places for queen egging and to embalm killed invaders. Chemically, Propolis of different parts of the world is constituted by 50-60% of resins, 30-40% of waxes, 5-10% of essential oils, 5% pollen, besides microelements like aluminum and calcium.  So far, more than 300 organic compounds of different groups mainly phenolic, such as: Flavonoids, stilbenes, phenolic acids and its esters have been identified from Propolis. Many biological activities have been reported for Propolis, such as antimicrobial, antiparasitic, antiviral, anti-inflammatory, antitumor, antioxidant, anesthetic and free radical scavenging action.  A pioneering pilot study was under taken on the effect of Propolis on dentinal hypersensitivity in vivo for a study period of 4 weeks.  It was concluded that Propolis had a positive effect in control of dentin hypersensitivity.
Thus, the primary objective of this 3-month study was to evaluate the clinical efficacy of topical Propolis preparation and to compare it with a topical 5% potassium nitrate preparation in the treatment of dentin hypersensitivity using distilled water as a control.
| Materials and methods|| |
The subjects included in this study were selected from outpatients attending the Department of Conservative Dentistry and Endodontics. The study was designed following consideration of the 1997 guidelines on clinical trials of dentine sensitivity. , The study was a 3-month, randomized, double blind study. The subjects fulfilling certain qualifying criteria were taken up for the study. ( Subjects included in the study were dentally mature individuals in the age group of 20-40 years, having sensitive teeth with a clinical diagnosis satisfying the definition of dentine hypersensitivity; subjects willing to participate in the study for 3 months; subjects with more than three hypersensitive teeth and the subjects capable of giving a written informed consent. Subjects excluded from the study included the patients who were on current desensitizing therapy, patients with medical (including psychiatric) and pharmacotherapeutic histories that may compromise the protocol-including the use of anti-inflammatory, analgesic and mind-altering drugs; patient who were pregnant or breast feeding; patients with allergies, idiosyncratic reactions or with eating disorders; patients with systemic conditions that are etiologic or predisposing to dentine hypersensitivity (e.g., chronic acid regurgitation); patients with excessive dietary or environmental exposure to acids; patients with the history of Periodontal surgery in the preceding 3 months (unless it is the effect of the agent on post-surgical sensitivity that is under study); patients with orthodontic appliance treatment with in previous 3 months; patients with painful pathology or defects in teeth or their supporting structures; patients who had their teeth restored in the preceding 3 months; patients with fixed or removable prostheses or extensively restored teeth with restorations extending into the test area.
Ten patients in the age group of 20-40 years with 156 hypersensitive teeth fulfilling the above-mentioned criteria were included in the study. The teeth selected for the study included canine, premolars and molars. Relevant information related to history, precipitating causes, and past treatment received for the condition was collected from each patient.
Thorough oral prophylaxis was done for all the patients. Following this, the patients were allocated to treatment. The agents were assigned as 5% potassium nitrate solution, alcoholic solution of Propolis (Hi-Tech Natural Products, India Ltd) and distilled water. Propolis extract was made by dissolving the Propolis into 70% ethanol and straining out the precipitate. The study was carried out in a double-blinded design, i.e., the patient, and the people analyzing the data were unaware of the agent. One experienced operator was involved in the application and other in the evaluation of the agent.
Freshly prepared potassium nitrate was used at each appointment. Based on the treatment received, the hypersensitive sites were divided into three groups:
• Group 1(Propolis)
• Group 2 (5% potassium nitrate)
• Group 3 (distilled water).
Fifty-two hypersensitive teeth were allocated in each group. Each patient received all the three treatments. The area to be treated was isolated with rubber dam and was dried using air spray. Propolis was applied with a brush and left undisturbed at the site for 5 minutes. Potassium nitrate and water was applied with saturated cotton pellets for 5 minutes. Patients were instructed not to rinse or to take anything for half an hour so that the desensitizing agent takes sufficient time to act without getting washed away. The patients were advised to use a soft toothbrush and a non-fluoridated tooth paste while brushing. Dietary counseling was also done in order to avoid intake of excessive dietary acids during the study period.
Pre- and post-treatment assessment was done at the baseline, 7 th day, 14 th day, 30 th day, 3 months and measurements were recorded by the same investigator.
Evaluation of hypersensitivity
The subject's sensitivity to stimuli was assessed by using a cold graded thermal test. The clinical evaluation of the sensitivity was done before and after the application of the agents at 1 st , 7 th , 14 th , 30 th day and at 3 months recall. A thermal testing technique developed by Brough et al. was used to quantify the patient's baseline response to a cold stimulus.  Each tooth included in the study was isolated with a rubber dam without a clamp, using finger adaptation only. The water temperatures used in this study were 20°C, 10°C and 0°C with a variance of +l°C for each temperature interval. Water temperature was maintained throughout the procedure by the use of thermal-insulated containers. The required water temperature was adjusted in each container by the addition of ice or hot water until the desired temperature was obtained. The water temperature was monitored by the use of a thermometer. The application of water was done using a disposable syringe. The syringe was changed after every patient. The syringes were kept in the water containers and remained there until used to transport and apply water to the exposure site. Each syringe was immediately returned to the container following use. Using the syringe and starting at 20°C the investigator flowed the water over the isolated exposed tooth surface until a sensitive response occurred or for a maximum of 3 s, if no response occurred.
The investigator waited for 2 minutes and then retested the tooth with water at 10°C. Delaying reapplication of water for 2 minutes between each application was attempted to allow the tooth to return to body temperature. The water temperature was finally decreased by 10°C intervals until a sensitive response was obtained or until the testing system's limit (0°C) was reached. As the thermal stimulus was applied, the thermal stimulus either will or will not elicit a sensitive response (yes/no). Following baseline data collection, the appropriate solutions, according to the treatment group assignment of each tooth, were applied by the examiner.
The facial surface was dried with gauze before the application of the treatment solutions. The investigator used a brush saturated with the treatment solution for Propolis and gauzes saturated with treatment solution for potassium nitrate and water and carefully placed them without burnishing on the exposed tooth surface for 2 minutes. The investigator again dried the tooth with gauze and immediately applied similarly the second coat of solution for an additional 3 minutes. After the tooth had been treated, the investigator determined the patient's immediate response to water temperatures using the identical procedure that was performed at baseline. Each tooth was treated and evaluated individually before proceeding to the next one. After all the teeth had been tested, the patient was instructed to use normal daily oral hygiene regimen and to avoid using any desensitizing dentifrices or any agents that contained fluoride. The teeth were again treated with agents at 7 th day, 14 th day and 28 th day. Additional post-treatment measurements at 7 th day, 14 th day, 28 th day and 3 months after initial treatment were made using the identical thermal testing technique used to establishing baseline and immediate response data.
| Results|| |
Ten subjects with 156 hypersensitive teeth completed the 3-month clinical study.
For purpose of data analysis the responses of the patients to the test temperatures were converted to a ranking as suggested by Brough et al. [ 11] The ranking were assigned as follows:
- 3 = 20°C
- 2 = 10°C
- 1 = 0°C
- 0 = No response.
The effectiveness of Propolis in reducing dentine hypersensitivity was compared with 5% potassium nitrate and placebo treatment at baseline, 7 th day, 2 weeks, 4 weeks and 3 month.
In Group 1, out of 52 teeth, 20 teeth reacted at 20°C, 32 teeth at 10°C before treatment as shown in [Table 1]. In Group 1, application of Propolis resulted in significant reduction in the temperature to which the patient responded immediately after treatment, at 1 week, 2 weeks, 4 weeks and 3 month after treatment. At the end of 3 months only 7 teeth reacted at 20°C, 9 teeth reacted at 10°C, 9 teeth react at 0°C and 27 teeth showed no response i.e., 51.9% teeth were completely free of sensitivity.
|Table 1: Response of teeth at various temperatures and different time intervals in propolis group (Group 1) |
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In Group 2 out of 52 teeth, 23 reacted at 20°C and 29 reacted at 10° before treatment as shown in [Table 2]. In Group 2, application of 5% potassium nitrate resulted in a significant reduction in the temperature to which the patient responded at 1 week, 2 weeks, 4 weeks and 3 month after treatment. At the end of 3 months only 12 teeth reacted at 20°C, 12 teeth reacted at 10°C, 13 teeth reacted at 0°C and 15 teeth showed no response i.e., 28.8% teeth were completely free of sensitivity.
|Table 2: Response of teeth at various temperatures and different time intervals in potassium nitrate group (Group 2) |
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In Group 3 out of 52 teeth, 24 reacted at 20°C and 28 reacted at 10°C before treatment as shown in [Table 3]. In Group 3, who were treated with placebo treatment, slight reduction in the temperature to which the patient responded after treatment was seen but it was not statistically significant at 1 week, 2 weeks and 4 weeks after the treatment. At the end of 3 months a significant response was seen. 17 teeth were reacting at 20°C, 20 teeth were reacting at 10°C, 7 teeth were reacting at 0°C, and 8 teeth showed no response.
|Table 3: Response of teeth at various temperatures and different time intervals in the distilled water group (Group 3) |
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To obtain intra-group and inter-group comparisons, mean values with standard deviations for different time periods in Groups 1, 2 and 3 were statistically analyzed. P value was set at 0.05 as shown in [Table 4] and following results were obtained.
|Table 4: Mean values with standard deviations of scores of the cold graded thermal test for different Groups at different time periods in Groups 1, 2 and 3 |
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A statistical analysis was done using ANOVA and multicomparison was done using the Bonferroni test and Tukey HSD test.
When the results were compared in intra group at baseline, immediately after treatment, 1 week, 2 weeks, 4 weeks and 3 months using the Bonferroni test, there was a significant difference . In Group 1, on comparison between baseline and immediately after treatment, 1 week, 2 weeks, 4 weeks and 3 months, the results were very highly significant (P = 0.001). On comparison between immediately after treatment and 1 week, the result was significant. A comparison between results immediately after treatment and 2 weeks was highly significant, with 4 weeks was not significant but was significant with 3 months. Rest of the comparisons were not significant. In Group 2, a comparison between baseline and immediately after treatment, 1 week, 2 weeks and 3 months were very highly significant as shown. On comparison between immediately after treatment and 1 week results were not significant, with 2 weeks results were significant, with 4 weeks results were highly significant but not significant with 3 months. Rest of the comparisons were not significant. In Group 3, comparisons of results between different time periods were not significant except between baseline and 3 months.
When baseline score of all the groups were compared with each other using the Tukey HSD test, there was no significant difference found (P > 0.05) as shown in [Table 5].
|Table 5: Intergroup comparison between different groups at different time intervals |
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Immediately after the treatment, the results between the groups showed that there was no significant difference between Group 1 and Group 2 and Group 2 and Group 3 but between Group 1 and Group 3 results were highly significant. A comparison at first week between groups showed that there was a significant difference between Group 1 and Group 2 and very highly significant difference between Group 1 and Group 3. Group 2 and Group 3 showed highly significant difference. At 2 weeks a comparison between groups showed same results as at first week. At 4 weeks a comparison between groups showed that there was no significant difference between Group 1 and Group 2 but there was very highly significant difference between Group 1 and Group 3 and also between Group 2 and Group 3. At 3 months a comparison between Group 1 and Group 3 was very highly significant but a comparison between Group 1 and Group 2 as well as Group 2 and Group 3 was insignificant.
| Discussion|| |
It has been reported that 15% of global population suffers from dentine hypersensitivity.  Till now no completely reliable treatment has been found; an agent can be of benefit in one case but fail in another. Search for an ideal agent still continues.
Natural products have been used for thousands of years in folk medicine for several purposes. Among them, Propolis a bee product has attracted increased interest due to its harmless nature and innumerable biological activities . Certain clinical studies have shown Propolis to be a promising dentine desensitizer in the treatment of dentinal hypersensitivity .  The authors explained the effect due to blockade of dentinal tubules in light of their SEM observation.  Literature review indicates that there has been no study comparing Propolis with a known desensitizing agent and a negative control.
The aim of this study was to evaluate the clinical efficacy of Propolis in a controlled study and compare it with a positive and a negative control. Potassium nitrate was used as a positive control as it is currently the most frequently used agents for control of hypersensitivity.  A purified saturated ethanolic extract of Propolis was used in the study.
One of the inherent problems of desensitizing studies is in the development of a technique and stimulus that will quantify reliably a patient's response to pain Only in few studies were fairly sophisticated thermoelectric measuring devices used.  These devices give a precise reading but are extremely expensive. In the present study, the Brough technique of using cold graded water enabled the investigator to confine the stimulus to the tooth being tested, was reproducible, inexpensive and could stimulate the irritation of a cold stimulus within a realistic temperature range.  As the thermal stimulus was applied, the temperature at which sensitivity was elicited was noted using the pain scoring system of Brough et al.  According to the system the thermal stimulus either will or will not elicit a sensitive response (Yes/No). They found that by asking the participant simply to report that the tooth was or was not painful eliminated the requirement that the patient classify the pain response e.g., mild, moderate, severe or very severe. This enabled the examiner to collect quantitative data and allowed for statistical analysis. This technique determines the degree of hypersensitivity through the use of a range of water temperatures applied directly to the exposed root surface.
Application of Propolis in Group 1 resulted in a significant reduction in the temperature to which the patient responded immediately after treatment in 19% of teeth and 25% teeth responded only at 0°C 5 minutes after treatment. This was followed by an increase in the efficacy of agent over a period of time with maximum relief from hypersensitivity by end of the study period i.e., 3 months. At 3 months after the application of the agent, 51% teeth very completely free of sensitivity and those that reacted only at 0°C decreased to 17.3%. Propolis thus had an immediate as well as increased sustained effect. The immediate relief could be due to its tubular sealing effect which prevents the flow of the dentinal fluid in the tubules, thereby preventing any alteration in the arrangement of the odontoblastic process and nerve endings. The long lasting of effect of Propolis probably could be due to stable nature of the deposits so formed. The retention and stability of the Propolis deposits in hostile oral environment needs further investigation and is not within the scope of this study. Over 3 months time response gradually reduced to only 28.8% teeth free from hypersensitivity and 25% teeth reacting at 0°C. Propolis is a power house of chemicals especially bioactive flavonoids. Flavonoids have been shown to have tissue regenerative activity. Propolis has been shown to stimulate various enzymes, cell metabolism, circulation and collagen formation, as well as improve healing.  Sabir et al. found that direct pulp capping with Propolis flavonoids in rats may delay dental pulp inflammation and stimulate reparative dentin formation.  In our study no histologic sections were taken to determine if Propolis formed reparative dentine, but this is a possible explanation for the decrease in sensitively at the 3-month interval.
Potassium nitrate acts by reducing the excitability of the interdental nerves in the pulp by depolarizing them. , Potassium ions have to traverse the length of the dentinal tubule in sufficient quantity to cause depolarization. The results show that at the end of 5 minutes after treatment, the concentration of potassium ions in the dentinal tubules was not sufficient to make the nerves in excitable and it takes longer time for the potassium ions to reach the nerves. The effect of desensitization achieved by K ions decreased with time and this could be attributed to a decrease in concentration of the ions in dentinal tubules.
The placebo treatment which was used in Group 3 was effective only to a certain extent. With 9.6% teeth free from sensitivity and 7.7% reacting at 0°C only, 5 minutes after treatment and increasing to 15.3% teeth free from sensitivity and 13.5% reacting at 0°C at the end of the study. Placebo effect consists of a complex mixture of physiologic and psychological interactions, depending considerably on the doctor patient relationship with both parties believing that the treatment is of value and the desire to obtain relief from symptoms. Despite randomization of subjects in the study, the enrolled subjects often try to please clinicians. Furthermore, positive emotional and motivational behavioral responses can activate the body's central pain inhibiting system, which can modulate painful stimuli from the periphery through the release of endorphins centrally.
Yet another possible phenomenon which could occur is the 'Hawthorne effect'.  This may influence the interpretation of the results. The 'Hawthorne effect' is a response to non-intervention procedure such as frequent examinations, improved oral hygiene or compliance with the treatment regimen. Patients frequently appear to improve merely from the effect of being placed on a trial. This reaction is thought to occur in many clinical trials. In this study, patients were reinforced in each visit about their oral hygiene and dietary acid consumption. Further, most patients like to have clean mouths if they attend the dental surgeon and will therefore by more vigilant about brushing during a period of frequent examination. These factors unintentionally alter behavior. Better oral hygiene may allow greater saliva access to patent dentinal tubules. This in turn may enhance tubules obliteration through deposition of salivary calcium, phosphate and proteins. The influence of Hawthorne effect may explain the change in the results from 5 minutes after treatment to end of study at 3 months. Many investigators have described patients obtaining relief without treatment due to placebo effect. , This is thought to vary from 20% to 60% in dentine sensitivity clinical trials. 
| Conclusion|| |
Observations from the present study are:
- Propolis was the most effective desensitizer providing both immediate relief which gradually increased by the end of 3 months
- 5% potassium nitrate was effective in reducing dentin hypersensitivity but to a lesser degree when compared to Propolis
- The placebo group failed to show any statistically significant difference than the other experimental agents and was not effective in reducing dentin sensitivity.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]