Australian Dental Journal

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1 Australian Dental Journal The official journal of the Australian Dental Association Australian Dental Journal 2013; 58: doi: /adj Clinical efficacy of a herbal dentifrice on dentinal hypersensitivity: a randomized controlled clinical trial M Kumari,* SB Naik, NS Rao,* SS Martande,* AR Pradeep* *Department of Periodontics, Government Dental College and Research Institute, Bangalore, India. Department of Conservative Dentistry and Endodontics, Government Dental College and Research Institute, Bangalore, India. ABSTRACT Background: Dentinal hypersensitivity is a common problem and there is a growing interest in herbal based formulations for the treatment of oral diseases. This study was conducted to assess the efficacy of a commercially available novel herbal dentifrice in reduction of dentinal hypersensitivity. Methods: A total of 73 subjects (38 males and 35 females; aged years) were randomly divided into two s: Group 1 a placebo dentifrice (The Himalaya Drug Company Research and Development, Makali, Bangalore) and Group 2 (test ), a commercially available herbal dentifrice (Hi Ora K, The Himalaya Drug Company Research and Development, Makali, Bangalore). Sensitivity scores for controlled air stimulus and cold water were recorded at baseline, 6 weeks and 12 weeks. Results: The test was found to be significantly better compared to the placebo at the end of 6 and 12 weeks in reduction of dentinal hypersensitivity. Conclusions: The novel herbal dentifrice can be recommended for treatment of dentinal hypersensitivity. Keywords: Clinical trial, dentifrice, dentine desensitizing agents, potassium nitrate, Spinacia oleracea. Abbreviations and acronyms: ANOVA = analysis of variance; DH = dentine hypersensitivity; VAS = visual analog scale. (Accepted for publication 21 December 2012.) INTRODUCTION Dentinal hypersensitivity (DH) is a characteristic pain arising from exposed dentine, typically in response to various stimuli such as thermal, evaporative, tactile, osmotic or chemical, which cannot be attributed to any other form of dental defect or pathology. 1 Dentine hypersensitivity is a common problem which affects 8% to 57% of the adult dentate population and peaks during the third and fourth decades of life. 2 4 Any tooth and tooth surface can be affected but dentine hypersensitivity has a predilection for the buccal cervical regions of canines and premolars. 5 According to Bissada 6 and Narhi et al., 7 when constantly present over a long time, DH can provoke chronic discomfort and emotional distress. In addition, it can make dental plaque control difficult. According to hydrodynamic theory by Braennstroem and Astroem, enamel or cementum loss in cervical areas and the consequent opening of dentinal tubules to the oral environment, under certain stimuli, allows the movement of dentinal fluid inside the tubules, indirectly stimulating the extremities of the pulp nerves, causing pain. 8 It was also found that open dentinal tubules serve as pathways for the diffusive transport of bacterial elements in the oral cavity to the pulp, which may cause a localized inflammatory pulpal response. 9 Microscopic examination reveals that patent dentinal tubules are more numerous and wider in hypersensitive dentine than in non-sensitive dentine. 10 The aetiology of dentine hypersensitivity is multifactorial and results from dentine exposure and the opening of dentinal tubules. 2 DH can manifest when dentine is exposed by enamel loss by abrasion, erosion or corrosion, or loss of cementum by brushing or periodontal treatment, 11 or more commonly, by the association of two or more of these factors. 12,13 Agents for topical relief of dentine hypersensitivity either block the exposed dentine tubules or have a direct desensitizing effect on the pulpal nerve fibres. 14,15 Treatments can be self-administered by the patient at home or applied by a dental professional in the dental office. 11 Various strategies have been used in the treatment of DH which include lasers, iontophoresis, dentine sealers and soft tissue grafting. 16 Toothpastes are the most widely used dentifrices for delivering over-the-counter desensitizing agents Australian Dental Association 483

2 M Kumari et al. The use of potassium nitrate as an effective desensitizing agent dates backs to the testimonial report of Hodosh in Since then, many pastes containing potassium chloride or potassium citrate have been made available. 18 It has been found that a single application of a 3% potassium oxalate gel resulted in a significantly higher reduction of DH at 14 and 21 days, when compared to the placebo. 19 However, to the best of our knowledge, there are no studies evaluating the effects of herbal based formulations containing potassium nitrate on dentinal hypersensitivity. In vitro studies have shown that phytocomplexes derived from rhubarb stalks (Rhubarb rhaponicum) and spinach leaves (Spinacia oleracia) used in different formulations, can be effective for topical treatment of dentinal hypersensitivity. These phytocomplexes reduced dentinal permeability by occluding dentinal tubules through the formation of calcium oxalate crystals. 20 Recently there has been a growing interest in natural products, and herbal based toothpastes have been found as effective as the conventionally formulated dentifrice in the control of plaque and gingivitis. 21 Herbal formulations have also been found to be effective in the prevention of dental caries. 22,23 However, to our knowledge there has been no study evaluating a herbal dentifrice containing potassium nitrate and Spinacia oleracia on DH. This was the first study which was conducted to assess and compare the efficacy of a commercially available novel herbal dentifrice containing potassium nitrate and Spinacia oleracia on DH compared to a placebo over a period of 12 weeks. MATERIALS AND METHODS This study was a single-centre, longitudinal, triple masked (investigators, individuals and statistician), randomized parallel-arm design. The study duration was 12 weeks, in which sensitivity scores were measured at baseline, 6 weeks and 12 weeks. The research protocol was initially submitted to the Ethical Committee and Review Board of the Government Dental College and Research Institute, Bangalore, India. After ethical approval was granted, subjects were selected from the outpatient section of the Department of Periodontics, Government Dental College and Research Institute, Bangalore, India. The duration of the study was from February 2012 to July The study consisted of two s: Group 1 a placebo dentifrice (The Himalaya Drug Company Research and Development, Makali, Bangalore, India) and Group 2 (test ), a commercially available herbal dentifrice (Hi Ora K, The Himalaya Drug Company Research and Development, Makali, Bangalore, India). Each gram of test dentifrice contained 2.5 mg Cinnamomum zeylanicum, 2.5 mg Syzygium aromaticum, 10.0 mg Spinacia oleracea, 6.0 mg Triphala, 4.0 mg Trikatu and 30.0 mg Suryakshara (Potassium nitrate) and 10.0 mg Yashada bhasma (zinc oxide), sodium benzoate, calcium carbonate with sorbitol, glycerine and xanthan gum. The placebo dentifrice contained calcium carbonate, sodium benzoate with sorbitol, glycerine and xanthan gum. The placebo dentifrice did not contain any of the herbal constituents present in the test. Sample size calculations were based on detecting a difference of 30% reduction in visual analog scale (VAS) scores 24 between the test and control s using a two-tailed significance level of 5% with a 90% power. A total of 100 individuals were assessed for eligibility and based on inclusion and exclusion criteria, randomized and categorized into two s, each containing 37 individuals in Group 1 (placebo ) and 36 individuals in Group 2 (test ). The randomization process was made externally by the statistical unit using a computer generated random table. Investigators were not involved in the randomization process, nor were they aware of the assigned in all outcome evaluations. The dentifrice were dispensed in tubes which had a similar cover design with lot numbers to ensure proper masking of the product from the individuals and the examiner (MK). Sixty subjects (33 males and 27 females) were finally considered because 13 failed to follow-up or discontinued the treatment. There were 30 subjects in each who finally completed the study. Subjects participating in the study were aged years. The mean age was not statistically different among s and ranged from 42.3 years for Group 1 and 41.9 years for Group 2. Subjects who were in good general health could fulfil the scheduled appointment and gave written informed consent to participate were recruited into the 12-week trial. A flow chart of the study is provided in Fig. 1. Inclusion exclusion criteria The individuals selected at baseline had a history of DH caused by gingival recession or cervical erosion. Subjects were required to have 20 natural permanent teeth and at least two teeth with a VAS score of 4 to be included in the study. Teeth with caries, defective restorations, chipped teeth, deep periodontal pockets (probing depth >4 mm), periodontal surgery within the previous six months, and subjects with orthodontic appliances or bridge work that would interfere with evaluation were excluded. 25 Subjects were also excluded if there was presence of occlusal overload or Australian Dental Association

3 Herbal dentifrice in dentinal hypersensitivity Assessed for eligibility (n = 100) Minimum two teeth with VAS score >4 for air and water stimuli examined Excluded Not meeting inclusion criteria (n = 19) Refused to participate (n = 8) Randomized (n = 73) by computer generated number sequence Male (n = 38) Female (n = 35) Allocated to interventionplacebo (n = 37) Allocated to intervention test (n = 36) Failed to follow-up (n = 4) Discontinued intervention (n = 3) Failed to follow-up (n = 4) Discontinued intervention (n = 2) Analysed (n = 30) Excluded from analysis (n = 7) Analysed (n = 30) Excluded from analysis (n = 6) Fig. 1 Consort flow chart. occlusal adjustment recently made in the tooth to be studied. Subjects who had undertaken treatment with any product that could influence the DH of the patient in the 30 days prior to baseline were excluded. 26 In addition, subjects were also excluded if they were allergic to ingredients used in the study or exhibited any gross oral pathology, eating disorders, chronic disease, pregnancy and lactation, acute myocardial infarction within the past six months, use of pacemaker, uncontrolled metabolic disease, major psychiatric disorder, heavy smoking or alcohol abuse, any systemic disease or any disease requiring repeated or regular analgesia, anti-inflammatory drugs, or antihistamines. 25 Sensitivity assessment Controlled air stimulus (evaporative stimulus) and cold water (thermal stimulus) were used to assess tooth sensitivity. Sensitivity was measured using a 10- cm VAS score, with the score of zero being a pain-free response and a score of 10 being excruciating pain or discomfort. Scoring of tooth sensitivity was done first by using controlled air pressure, from a standard dental syringe at 40 to 65 psi at ambient temperature, directed perpendicularly and at a distance of 1 to 3 mm from the exposed dentine surface while adjacent teeth were protected with gloved fingers to prevent false positive results. 25 The second stimulus for testing tooth sensitivity was done after a period of at least five minutes using 10 ml of ice cold water applied to the exposed dentine surface, keeping the neighbouring teeth isolated during testing by using the operator s fingers and cotton rolls. 25 After recording sensitivity scores at baseline (investigator MK), subjects were randomly given dentifrice by a dental assistant not involved in the study and advised to use it with a soft bristle toothbrush twice a day. Subjects were also directed to refrain from using any other dentifrice or mouthrinse during the trial but were allowed to continue their normal oral hygiene 2013 Australian Dental Association 485

4 M Kumari et al. practice during the trial period. Intra-examiner calibration was performed on 20 individuals before the study and the intra-examiner agreement was 95.2% (j = 0.905). Apart from the clinical evaluation, a subjective evaluation was also undertaken at each visit, using a questionnaire relating to the taste and flavour of the dentifrice or any adverse effect experienced after use. To check for compliance, participants were asked to return their assigned tubes so that the investigator could verify the amount of dentifrice that was used. Table 2. Sensitivity scores to air and water stimulus in test and placebo s at all time points Stimulus Group Baseline 6 weeks 12 weeks Mean SD Mean SD Mean SD Air stimulus Water stimulus Placebo Test Placebo Test Statistical analysis Mean VAS scores and mean SD were calculated from raw VAS scores from all individuals in a treatment. Mean VAS scores were compared among s at different time points (baseline, 6 and 12 weeks) and among s at each time point using one-way analysis of variance (ANOVA). Post hoc pairwise multiple comparisons were done using the t-test and p < 0.01 was taken as significant when detected. Data were statistically analysed using a software programme (SPSS Statistical Package, Version 17.5, SPSS, Chicago, IL, USA). RESULTS Table 1 shows type of tooth included in the study. Mean VAS scores for air stimulus and water stimulus for both s at baseline, 6 weeks and 12 weeks are shown in Table 2. There was no significant difference in baseline scores in both s for both air and water stimulus. Intra- comparison of percentage change in mean sensitivity showed that the test resulted in significant improvements from baseline to 6 weeks ( 33.64%, 44.35%); baseline to 12 weeks ( 45.79%, 57.74%) and between 6 weeks and 12 weeks ( 18.31%, 24.06%), to both air and water stimulus (Table 3). Negative value in all percentage change in sensitivity scores showed that there was a reduction in sensitivity score from baseline to 6 and 12 weeks. Tables 4 and 5 show inter Table 1. Types of teeth included in study Types of teeth Teeth selected by investigators (%) Upper central incisors 7.9 Upper lateral incisors 9.9 Upper canine 12.5 Lower central incisors 11.3 Lower lateral incisors 12.7 Lower canine 8.1 Upper premolars 10.2 Lower premolars 11.1 Upper molars 8.5 Lower molars 7.8 comparison of percentage change in air and water sensitivity scores at all time points. There was a significant difference between the test and the placebo, for air stimulus and water stimulus at all-time intervals. The percentage change difference was greater for water stimulus at all time points (Tables 3 and 5). On subjective evaluation, all individuals gave positive responses regarding the taste and flavour of both dentifrices and no adverse effects were observed. DISCUSSION The current study compared commercially available herbal dentifrices and placebo. The results of the present study demonstrated a reduction in symptoms of DH for the test product from baseline to 6 and 12 weeks for both measures of sensitivity. There was a remarkable pattern towards reduction of DH with time for both variables during the 12 weeks of the active phase of the study in the test (Fig. 2 and 3). The test product consisted of the following constituents: Cinnamomum zeylanicum, Syzygium aromaticum, Spinacia oleracea, Triphala, Trikatu and Suryakshara. Cinnamomum zeylanicum has been found to have bactericidal properties and is found to be equally effective against both Gram-positive and Gram-negative organisms. Cinnamaldehyde, the predominant active compound in cinnamon oil, has been found to be a natural antioxidant. 27 Extract of Syzygium aromaticum (clove) has been found to exhibit growth-inhibitory activity against Gram-negative anaerobic periodontal oral pathogens, including Porphyromonas gingivalis and Prevotella intermedia. 28 Triphala has been found to have similar effects on dental plaque and gingival inflammation compared to chlorhexidine. 29 Trikatu has anti-inflammatory properties. 30 Yashada bhasma contains zinc and has been formulated into oral health products to control plaque, reduce malodour and inhibit calculus formation. 31,32 The components responsible for reducing DH in the test were Suryakshara (potassium nitrate) and Australian Dental Association

5 Table 3. Paired test: percentage change in mean sensitivity scores for two s at all time points for both measures of sensitivity Measure of sensitivity Groups Change in mean sensitivity score (%) Baseline to 6 weeks Baseline to 12 weeks 6 to 12 Weeks Air stimulus Placebo Test 33.64* 45.79* 18.31* Water stimulus Placebo Test 44.35* 57.74* 24.06* *Statistically significant at p-value <0.01. Herbal dentifrice in dentinal hypersensitivity Table 4. Comparison of two s of percentage change in air sensitivity scores by unpaired t-test Groups Differences in percentage of change Baseline to 6 weeks Baseline to 12 weeks 6 to 12 weeks Mean SD Mean SD Mean SD Placebo Test t-value P-value * * * *Statistically significant at p-value <0.01. Table 5. Comparison of two s of percentage change in water sensitivity scores by unpaired t-test Groups Differences in percentage of change Baseline to 6 weeks Baseline to 12 weeks 6 to 12 weeks Mean SD Mean SD Mean SD Placebo Test t-value P-value * * * *Statistically significant at p-value <0.01. MEAN Placebo Test Baseline 6 Weeks 12 Weeks Fig. 2 Sensitivity scores to air stimulus. MEAN Placebo Test Baseline 6 Weeks 12 Weeks Fig. 3 Sensitivity scores to water stimulus. Spinacia oleracea. These components were absent in the placebo. Studies have found that pastes containing 5% potassium nitrate significantly decreased DH when compared with baseline or negative controls. The results of this current study are in accordance with all these previous studies. The test consisted of 2013 Australian Dental Association 487

6 M Kumari et al mg Suryakshara (potassium nitrate) in each gram of dentifrice in a herbal based formulation. It has been found that potassium nitrate does not diminish dentine hydraulic conductivity, or promote obstruction of dentinal tubules by the deposition of crystals. 36 According to Wilchgers and Ermert 37 and Kim, 14 potassium nitrate has an effective desensitizing action. The increase in the concentration of extracellular potassium around the nerve fibres causes their depolarization, avoids repolarization and blocks the axonic action and passage of nerve stimulus, thus inactivating the action potential. 36,37 Moreover, the test also consisted of 10.0 mg Spinacia oleracea per gram of dentifrice. It has been found that soluble oxalates and oxalic acid in phytocomplexes present in Spinacia oleracea (spinach leaves) form calcium oxalate crystals by reacting with dentinal calcium. 20 Calcium oxalate crystals present in lyophilized phytocomplexes may penetrate inside dentinal tubules if their dimensions are less than 1 2 mm. The ratios of calcium and oxalate/calcium determine the effect of phytocomplexes on dentinal tubule occlusion. Low amounts of calcium and excess oxalate (oxalate/calcium ratio >1) induce binding of oxalate to calcium, producing calcium oxalate directly inside dentinal tubules. 38 Oxalate crystals are small enough to penetrate the tubules and occlude tubular orifices. A study has shown that treatment with oxalate-containing phytocomplexes induce microcrystal deposition on dentine and inside dentinal tubules and thus reduce the tubular diameters by forming crystals or crystallike structures. 20 As Spinacia oleracea was absent in the placebo, the reduction in DH could also be probably due to Spinacia oleracea present in the test. As stated earlier, potassium nitrate lack ability to occlude dentinal tubules, 36 therefore Spinacia oleracea may have a possible mechanism of having a synergistic effect along with potassium nitrate in reducing DH by its dentinal tubule obliterating property. For generalized sensitivity involving several teeth, the use of a desensitizing dentifrice with strontium chloride and potassium nitrate produced relief in 2 4 weeks. 18 Therefore, the duration of the current study was 12 weeks with sensitivity measurement at baseline, 6 and 12 weeks. Pain associated with DH has been difficult to quantify and reproduce. 39 Tolerance to the same pain can vary considerably among different individuals, and even in the same individuals depending on the time and circumstances as the perception of pain depends on individual factors such as personality, psychological factors and educational level. 40 The threshold of pain can vary by suggestion and by changes in the emotional state of the subject. 41 It is recommended that at least two hydrodynamic stimuli must be used in the clinical trials. 42 Evaporative air stimulus was used first for sensitivity assessment, followed by water stimuli in our study because the least severe stimulus should be applied first to prevent interpretation error. The interval of 5 minutes was allowed between the two stimuli to minimize interactions between stimuli. 25 In the present study, the placebo also reported reduction in mean sensitivity scores over time. This could be because of the placebo effect, which varies from 20% to 60% in DH clinical trials. 43,44 Yet another possible phenomenon, which could cause such change, is the Hawthorne effect. The influence of the Hawthorne effect is difficult to calculate. This effect is a response to non-intervention procedures, such as improved oral hygiene or frequent examinations. 1 In the current study, no adverse effects were observed and there was no incidence of caries. Some of the constituents of the test product have shown anticaries effects in previous studies. 22,23 Cinnamon oil and clove oil have shown antibacterial activity against bacterial species involved in dental caries like Streptococcus mutans. 22 Triphala has also been found to be effective in preventing a significant increase in the caries. 23 Moreover, zinc oxide has also shown a significant effect on the inhibition of dentine demineralization and may be effective in the prevention of caries. 45 CONCLUSIONS This was the first study in which a herbal based dentifrice was used in the treatment of dentinal hypersensitivity. The test (Hi Ora K) showed better reduction in the symptoms of dentine hypersensitivity compared to the placebo. However, further long-term multicentre three-armed parallel randomized controlled clinical trials are required in which other commercially available dentifrices containing potassium salts, fluorides or calcium sodium phosphosilicate, is used and compared with this herbal formulation to confirm the findings of this study. Hence, the novel herbal dentifrice can be recommended for treatment of DH. ACKNOWLEDGEMENTS The present study was funded by The Himalaya Drug Company Research and Development, Makali, Bangalore, India. The authors thank Dr Prahalad Patki, The Himalaya Drug Company Research and Development, Makali, Bangalore for providing the samples. The authors also thank Dr SB Javali, Dharwad, India, for performing the required statistics Australian Dental Association

7 Herbal dentifrice in dentinal hypersensitivity DISCLOSURE The authors declare that they have no conflict of interests. Authors declare no financial support or relationships that may pose conflict of interest. REFERENCES 1. Dowell P, Addy M. Dentine hypersensitivity a review, aetiology, symptoms and theories of pain production. J Clin Periodontol 1983;10: Addy M. Etiology and clinical implications of dentine hypersensitivity. Dent Clin North Am 1990;34: Irwin CR, McCusker P. Prevalence of dentine hypersensitivity in a general dental population. J Ir Dent Assoc 1997;43: Rees JS, Addy M. A cross-sectional study of buccal cervical sensitivity in UK general dental practice and a summary review of prevalence studies. Int J Dent Hyg 2004;2: Flynn J, Galloway R, Orchardson R. The incidence of hypersensitive teeth in the West of Scotland. J Dent 1985;13: Bissada NF. Symptomatology and clinical features of hypersensitive teeth. Arch Oral Biol 1994;39:31S 32S. 7. 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8 M Kumari et al. 43. Uchida A, Wakeno Y, Fukuyamo O, Miki T, Iwayama Y, Okada HI. Controlled clinical evaluation of a 10% strontium chloride toothpaste in the treatment of dentine hypersensitivity following periodontal surgery. J Periodontol 1980;51: Zinner DD, Duany LF, Lutz HJ. A new desensitizing toothpaste. Preliminary report. J Am Dent Assoc 1977;95: Takatsuka T, Tanaka K, Iijima Y. Inhibition of dentine demineralization by zinc oxide: in vitro and in situ studies. Dent Mater 2005;21: Address for correspondence: Dr AR Pradeep Professor and Head Department of Periodontics Government Dental College and Research Institute Bangalore Karnataka India periodonticsgdcri@gmail.com Australian Dental Association