Quintessence Journals

pyri ORIGINALCo ARTICLEgh Not for Publicationt

b y Q

Comparison of Two Different Forms of Varnishes in the N

n o

t t r f e o Treatment of Dentine Hypersensitivity: A Subject-Blindssence Randomised Clinical Study*

Gulnar Dara Sethnaa/M.L.V. Prabhujib/B.V. Karthikeyanc

Purpose: Dentine hypersensitivity is one of the most frequently recorded complaints of dental discomfort. Current evidence implicates patent dentinal tubules in hypersensitive dentine, and it follows that one effective way to reduce dentine sensitivity is to occlude the dentinal tubules. The purpose of this study was to compare the efficacy of two different desensitising agents, Cervitec varnish and Gluma varnish.

Materials and Methods: Two hundred fifty patients self-reporting dentine hypersensitivity completed the paired split mouth randomised, subject-blind study. Each participant had a minimum of two sensitive teeth in at least two different quadrants and displaying a response of ≥3 cm to an evaporative stimulus. The hypersensitivity levels were measured with a tactile stimulus (scratchometer), thermal stimulus (cold water test), and an evaporative stimulus (air blast test) using a visual analogue scale. The teeth were evaluated immediately after treatment, and at 4 and 12 weeks after application of the chlorhexidine-containing varnish Cervitec and the glutaraldehyde-containing varnish, Gluma Desensitizer.

Results: Statistical analysis indicated that both the desensitising varnishes were effective in alleviating dentine hypersensitivity at all time intervals compared to baseline. There was a highly statistically significantly greater reduction in dentine hypersensitivity to evaporative stimulus, cold stimulus, and tactile stimulus after application of Cervitec than after Gluma Desensitizer (P < 0.001).

Conclusion: Both the varnishes have a therapeutic potential to alleviate dentine hypersensitivity at all time intervals compared to baseline. However, Cervitec varnish is more efficacious in reducing dentine hypersensitivity than Gluma varnish at both 4 weeks and 12 weeks post-treatment.

Key words: dentine hypersensitivity, Cervitec varnish, Gluma varnish, visual analogue scale, scratchometer, thermal test

Oral Health Prev Dent 2011; 9: 143-150 Submitted for publication: 13.05.10; accepted for publication: 29.07.10.

he term dentine hypersensitivity has been used ology’ (Banoczy, 2002). In 1982, Johnson and co- Tfor decades and has been defined as ‘short workers stated that ‘dentine hypersensitivity is an sharp pain arising from exposed dentine in re- enigma being frequently encountered yet ill under- sponse to stimuli typically thermal, evaporative, stood’ (Addy, 2000). tactile, osmotic or chemical and which cannot be Besides causing discomfort, this condition may ascribed to any other form of dental defect or path- deter a patient from establishing or maintaining adequate oral hygiene procedures, which may ad- * This study was conducted as part of an MDS dissertation at the versely affect gingival and periodontal health. Krishnadevaraya College of Dental Sciences under the guidance of Thus, the vicious cycle of sensitive teeth leading Drs Prabhuji and Karthikeyan. to reduced plaque control, more periodontal dis- a Private Practice, Mumbai, India. ease and more recession may be established b Head, Department of Periodontics, Krishnadevaraya College of (Dowell, 1985). One of the factors which play an Dental Sciences, Bangalore, Karnataka, India. (Dr Sethna’s MDS supervisor) important role in the etiology of dentine hypersen- c Reader, Department of Periodontics, Krishnadevaraya College of sitivity may be plaque accumulation (Kakaboura Dental Sciences, Bangalore, Karnataka, India. and Rahiotis, 2005). Plaque and plaque products Correspondence: Dr G. Sethna, Chicago Center of Advanced Den- which invade the dentinal tubules bring about de- tistry, METROPOLIS, Firuz Ara,160 Backbay Reclamation, Madam calcification of peritubular dentine. This eventually Cama Road, Near Mantralaya 23, Mumbai 400 021, India. Tel: +91-22-2283-6440-441-442, Fax: +91-080-284-677-083. enlarges the tubules and leads to dentine hyper- Email: [email protected] sensitivity.

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b y Although several hypotheses have been advocat- The literature bears evidence ofQ the potential

u ed to explain how external stimuli may influence the role of chlorhexidine (CHX) and glutaraldehyde de-N

nerve fibers, the most widely accepted is the hydro- sensitiser as effective desensitisingn agents (Ar-o

t t r f e o dynamic theory, where the movement of fluid within rais, 2004; Kakaboura and Rahiotis, 2005).ssen How-ce the dentine transduces surface stimuli by deforma- ever, to the best of our knowledge, there are no tion of pulpal mechanoreceptors, which in turn studies reported in the literature comparing the causes pain and hypersensitivity (Addy and West, efficacy of CHX vs glutaraldehyde as desensitising 1994; Brannstrom and Astrom, 1964). Approaches agents for the treatment of dentine hypersensitivity. to preventing or treating dentine hypersensitivity in- In view of this fact, the present study was under- clude reaction of exposed surfaces with chemical taken with the objective of comparing the efficacy agents which might either occlude dentinal tubules of Cervitec varnish with Gluma varnish as desensi- or make smear layer covered surfaces resistant to tising agents. tubular exposure (Addy, 2000). A number of desensitising agents have been used to alleviate the pain caused by dentine sensi- MATERIALS AND METHODS tivity. These include neural stimulus blockers (Or- chardson, 2006), protein precipitants, tubule oc- Three hundred patients (140 males and 160 fe- cluding agents and tubule sealants (Jacobsen and males; age range 20 to 55 years) who attended the Bruce, 2001), fluoride iontophoresis (Kern und Mc- outpatient section, Department of Periodontics, Quade), and lasers (Schwarz and Arweiler, 2002). Krishnadevaraya College of Dental Sciences, However, none of them have shown to be consist- Bangalore, were randomly selected for the clinical ently effective (Panduric and Sutalo, 2001). study conducted from March 2008 to Dec 2009. Chlorhexidine has been widely accepted as an Recruitment of the patients was stopped in Sep- anti-plaque and antimicrobial agent. It is adsorbed tember 2009; of the total 300 patients recruited in to enamel and dentine surfaces and prevents ad- the study, 50 were excluded (attrition rate of 16.8 sorption of bacteria, thereby exerting an anti-plaque %). and anti-bacterial activity. It is thought to be one of Those patients with self-complaint of tooth hy- the best chemicals to control plaque and prevent persensitivity in at least two teeth present in differ- plaque-related morphological changes dentinal tu- ent quadrants of the mouth, buccal gingival reces- bules (Kakaboura and Rahiotic, 2005). A commer- sion and/or exposed dentine greater than 2 mm cially available chlorhexidine containing varnish, from the cementoenamel junction (CEJ), and a re- Cervitec (1% thymol and 1% chlorhexidine, Ivoclar sponse of ≥ 3 cm on a 10-cm scale to an evapora- Vivadent; Schaan, Liechtenstein), decreases bacte- tive stimulus were selected for the split-mouth, rial colonisation on the teeth, disrupts the bacterial subject-blind randomised clinical study. Patients metabolism and reduces formation of lactic acid. with defective restorations, root caries, deep perio- This varnish creates a mechanical barrier after dry- dontal pockets, dentures or bridgework, orthodon- ing and effectively seals the dentinal tubules with tic appliances, history of use of dental desensitis- no known adverse effects. It may thus be valuable ing agents, or those who had received periodontal in the treatment of dentine hypersensitivity (Pan- therapy in the preceding six months were excluded duric and Sutalo, 2001). from the study. The protocol was clearly explained Glutaraldehyde (5%) and hydroxyethylmeth- to all the patients and written consent was obtained acrylate (HEMA, 35%) in a varnish (Gluma Desensi- from all the subjects. The study protocol was ap- tizer, Heraeus Kulzer; Hanau, Germany) are used in proved by the Ethics Committee, Krishnadevaraya the treatment of dentine hypersensitivity. Glutaral- College of Dental Sciences, Rajiv Gandhi University dehyde acts as a biological fixative and forms a of Health Sciences, Bangalore, India. physiological seal by coagulating the plasma proteins in the dentinal tubules (Arrais, 2004). Simi- larly, HEMA is also a hydrophilic monomer com- Screening and study protocol pound found in dentine bonding agents with an ability to infiltrate into acid-etched and moist dental The oral examination was conducted on all subjects hard tissues. It causes precipitation of serum pro- to ensure that they were in good general health ex- teins in the dentinal tubules, thus also alleviating cept for the symptoms of dentinal hypersensitivity. dentine hypersensitivity (Schupbach et al, 1997). Detailed clinical and radiographic investigations

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b y Q

300 patients included in the study N

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t t r f ess o e r 50 drop outs due to change of residence, ill health. enc r Patient undergoing root canal treatment/dental restorations in the same quadrant.

500 sites assessed in 250 patients To test 250 sites (Cervitec) To test 250 sites (Gluma Desensitizer)

Follow-up Immediately after varnish application 4 weeks after baseline 12 weeks after baseline

Fig 1 Flow chart describing the eligibility criteria, number of subjects examined, and the follow-up over a period of 12 weeks after application of Cervitec and Gluma Desensitizer.

were performed on all the patients to exclude con- Pain measurement and stimulus application ditions of teeth which might have caused pain similar to that of dentine hypersensitivity. The study Pain was measured using a visual analogue scale protocol is shown in Fig 1. After baseline pain as- (VAS), a method which assesses a characteristic or sessment, computer-generated tables were used attitude that is believed to range across a continu- to randomise the side of desensitising agent appli- um of values and cannot be easily objectively meas- cation (left or right) to the Cervitec and the Gluma ured. Subjects were asked to record their overall Desensitizer group. Retrospective calculation of sensitivity by marking a point on a 10-cm VAS, the power of the study using the evaporative stimu- where 0 indicated ‘no pain’ and 10 ‘unbearable lus was 99.99% (α = 0.05%). pain’ experienced due to a blast of air, cold water The subject-blind, randomised clinical trial was application, and tactile stimuli (Gillam and New- conducted for 12 weeks and involved treatment of man, 1993; Scott and Huskisson 1979). 250 patients with a minimum of two hypersensitive Data were recorded on tactile (scratchometer), teeth in opposite arches/contralateral arches. The thermal (freshly melted ice water) and evaporative subjects and the outcome assessors were blinded stimuli (air blast test) (Gillam and Newman, 1993; as to the actual varnish received by the subjects. Kleinberg and Kaufman, 1990). These variables were measured at baseline, immediately after treatment, and 4 and 12 weeks after baseline treatment Examiners with Cervitec and Gluma Desensitizer. Tactile stimulus: A hand-held strain gauge de- Three trained dentists (M.L.V., B.V.K, and G.D.S.) vised by the Department of Biotechnology, MVIT acted as examiners and were individually responsi- College, Bangalore, India, based on the principles ble for applying the stimuli and the varnishes, and of the original scratchometer as designed by Dr collecting subjects’ responses during recall visits. Israel Kleinberg (Kleinberg and Kaufman, 1990), re- Calibration of examiners in their assessment of the corded the forces required to elicit a painful re- study outcome was not necessary, since the pa- sponse over a range of 10 to 100 g. An initial force tients provided subjective study responses. In addi- of 15 g was applied, and increased by a 5-g load at tion, because the delivery methods differed for the 2-min intervals until the patient responded or a CHX and glutaraldehyde varnishes, examiner blind- 70-g force was reached. The load at which the pa- ing was not viable during the application phase, but tient experienced pain was recorded as the thresh- was exercised during follow-up visits (Ritter and de old value. Dias, 2006). Thermal stimulus: The subject’s sensitivity to thermal stimuli was determined using a disposable

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b y syringe with a 0.5-mm-diameter needle and con- and comparisons were made betweenQ pairs of

u taining 0.5 ml freshly melted ice-cold water (up to treatments using Wilcoxon’s rank-sum test. Further,N

10°C). Water was applied to the test tooth surface the Friedman test was applied to determinen the sig-o

t t r f e o with the tip 2 mm from the tooth surface. The re- nificance between CHX varnish and thes sglutaralde-ence sponse was measured on the VAS based on the hyde desensitiser group. perception of pain by the subject. Evaporative stimulus: A blast of air from a dental 3-way syringe at a pressure between 45 and 60 psi RESULTS was placed perpendicular to the tooth for 1 s at a distance of 2 mm from the tooth surface. Adjacent Of the 300 subjects who were included in the study teeth were shielded by the operator’s fingers. design, 50 were excluded (drop outs due to ill A 10-min rest period was given between each test health, change of address, or root canal treatment stimulus applied to the tooth to allow the test tooth in the same quadrant) (Fig 1). to return to normal and adapt to temperature chang- Tables 1 to 3 show the mean sensitivity scores es (Kleinberg and Kaufman, 1990). The order of ap- at each assessment and the significance levels plication of stimuli was randomised, except that the (Wilcoxon’s test). Overall, both treatment groups air blast – generally considered to be the most se- showed a reduction in dentine hypersensitivity after vere stimulus – was applied last (Gillam and New- the application of various stimuli at all time inter- man, 1993; Holland et al, 2002). Patients were in- vals (baseline, 4 and 12 weeks). No adverse ef- structed not to use any desensitising tooth pastes fects were observed in either group. However, CHX during the 12-week study period. All subjects were varnish showed a statistically significantly greater asked to refrain from eating, drinking or brushing reduction in dentine hypersensitivity than did the their teeth 45 minutes prior to sensitivity evaluation. glutaraldehyde desensitiser at all time intervals compared to baseline. A comparison of the performance of the two var- Study medication nishes in the VAS response to tactile (Table 1, Fig 2), thermal (Table 2, Fig 3), and evaporative Gluma Desensitizer is dispensed in a 5-ml bottle stimuli (Table 3, Fig 4) indicated that both the de- containing 35% HEMA and 5% glutaraldehyde, while sensitising varnishes were effective in alleviating Cervitec is dispensed in a 1.5-ml amber-colored dentine hypersensitivity at all time intervals com- bottle containing 1% thymol and 1% chlorhexidine. pared to baseline. However, the CHX varnish yield- The teeth to be treated were isolated with cotton ed a statistically significantly greater reduction in rolls, cleaned and dried with cotton pellets. A drop dentine hypersensitivity to tactile, cold and evapo- of Gluma Desensitizer was then applied using cot- rative stimuli than did the glutaraldehyde desensi- ton micro-applicator tips (disposable applicator tiser (P < 0.001). brush tips, 3M ESPE; Bangalore, India) and left for 30 s. The surface was then carefully dried with a stream of air until the fluid film had disappeared DISCUSSION and the surface was no longer shiny. The patient then rinsed thoroughly with water. Cervitec was ap- It is apparent from the literature that no universally plied according to a similar protocol, except that accepted or totally effective method exists for treat- patients were asked not to rinse with water after ment of dentine hypersensitivity (Holland et al, application of the varnish. 2002). Relatively little is known of the etiology of dentine hypersensitivity, the nature of the lesion, or the status of the pulp. This lack of knowledge Statistical analysis makes the management of the condition more dif- ficult, and recurrences may appear frequently (Por- The nature and distribution of variables indicated to et al, 2009). According to the hydrodynamic the- that analysis by a nonparametric method was ap- ory of dentine sensitivity, a rapid movement of fluid propriate. The mean score for each treatment group in the dentinal tubules is capable of activating intra- was determined for each of the assessments of dental sensory nerves and causing dentine hyper- pain from tactile, thermal, and evaporative stim- sensitivity. Therefore, the treatment of hypersensi- uli. Means and standard deviations were calculated tive teeth should be directed towards reducing the

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b y Table 1 Mean tactile scores Q

Evaluation Cervitec Gluma iP values N

Desensitizer n o

t t r f ess o ce Before treatment 38.07 ± 15.15 40.73 ± 17.35 0.200en

Initial assessment 60.07 ± 14.93 51.87 ± 19.35 <0.001**

4 weeks post-treatment 71.13 ± 12.76 59.07 ± 13.99 <0.001**

12 weeks post-treatment 72.67 ± 15.31 61.13 ± 14.61 <0.001**

** Highly statistically significant reduction in dentine hypersensitivity to tactile stimulus after application of Cervitec vs Gluma Desensitizer.

10 9 8 7 6 5 4 3 Mean tactile scores 2 CERVITEC 1 GLUMA Fig 2 The change in tactile VAS 0 scores from baseline to 12 Immediate Reduction Reduction reduction after 4 weeks after 12 weeks weeks after application of Cer- vitec and Gluma Desensitizer.

Table 2 Mean VAS scores for thermal stimulus

Evaluation Cervitec* Gluma P values

Before treatment 6.53 ± 1.55 6.67 ± 2.16 0.557

Initial assessment 3.20 ± 2.45 5.23 ± 2.66 <0.001**

4 weeks post-treatment 2.80 ± 2.43 4.33 ± 2.53 <0.001**

12 weeks post-treatment 2.01 ± 1.92 3.95 ± 2.95 <0.001**

** Highly statistically significant reduction in dentine hypersensitivity to thermal stimulus after application of Cervitec vs Gluma Desensitizer.

10 9 8 7 6 5 4 3 Mean thermal scores 2 CERVITEC 1 GLUMA Fig 3 The change in thermal 0 VAS scores from baseline to 12 Immediate Reduction Reduction weeks after application of Ce reduction after 4 weeks after 12 weeks vitec and Gluma Desensitizer.

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b y Table 3 Mean VAS scores for evaporative stimulus Q

Evaluation Cervitec Gluma P values i N

n o

t t r f e o Before treatment 7.10 ± 1.29 6.89 ± 1.85 0.299 ssence Initial assessment 2.93 ± 1.67 4.00 ± 2.20 <0.001**

Assessment after four weeks 2.13 ± 1.99 3.51 ± 2.53 <0.001**

Assessment after twelve weeks 1.81 ± 1.98 2.95 ± 2.37 <0.001**

** Highly statistically significant reduction in dentine hypersensitivity to evaporative stimulus after application of the Cervitec as compared to the Gluma Desensitizer.

2 Mean evaporative scores CERVITEC 1 GLUMA Fig 4 The change in evaporative 0 VAS scores from baseline to 12 Immediate Reduction Reduction reduction after 4 weeks after 12 weeks weeks after application of Cer- vitec and Gluma Desensitizer. functional diameter of the tubules so as to limit Arends and Ruben (1993) proposed that the root fluid movement. Impregnation of dentinal tubules dentine acts as a chlorhexidine depot, slowly re- with plastic resins and adhesive material to seal off leasing chlorhexidine for up to 6 months after one the tubules has been suggested in light of the hy- application of Cervitec, with a release of chlorhex- drodynamic theory (Panduric and Sutalo, 2001). idine at the rate of 1 μg/cm2 dentine/day. One of the factors which plays an important role Gluma Desensitizer contains 35% HEMA and 5% in the etiology of dentine hypersensitivity may be glutaraldehyde and has been used successfully as plaque accumulation. In situ experiments by Kawa- a desensitising agent. The HEMA in the varnish in- saki et al (2001) showed that the accumulation of duces precipitation of the serum proteins within the plaque on the dentinal surface resulted in gradual dentinal tubules, thus achieving dentine tubule oc- enlargement of the dentinal tubules’ openings. It is clusion (Duran and Sengun, 2004). Schupbach et speculated that patients who maintain effective al (1997) reported that glutaraldehyde in the var- plaque control complain less of dentine hypersensi- nish is an effective fixative or flocculating agent tivity (Manochehr and Pour, 1984). with the capacity to form a coagulation plug within Adsorbing to enamel and dentine surfaces, chlor- the dentinal tubules; this may counteract the hydro- hexidine prevents adsorption of bacteria and there- dynamic mechanism of dentine hypersensitivity by exerts an anti-plaque and anti-bacterial activity. and bring about tubular occlusion of dentine up to It is thought to be one of the best chemicals to a depth of 50 to 200 μm. Interesting results were control plaque and prevent plaque-related morpho- found by Kakaboura and Rahiotis (2005), who eval- logical changes of dentinal tubules (Kakaboura and uated the clinical effectiveness of One-Step and Rahiotis, 2005). Cervitec, a varnish containing Gluma Desensitizer on the treatment of tooth cervi- chlorhexidine, may be valuable in the treatment of cal hypersensitivity. Their study found that both dentine hypersensitivity by decreasing the bacterial treatment procedures resulted in reduction of hy- colonisation on the teeth and creating a mechani- persensitivity for up to 9 months. In this study, a cal barrier, which may enhance the sealing of the split-mouth design was employed, because it al- dentinal tubule (Kakaboura and Rahiotis, 2005). lows the determination of superiority between the

148 Oral Health & Preventive Dentistry pyri SethnaCo et galh Not for Publicationt

b y treatments where clear clinical and statistical supe- In the present study, the reduction Qof dentine hy-

u riority has been demonstrated. In a split-mouth persensitivity immediately after application of the N

study, the patient is matched to him- or herself or desensitising agents and at 1 and 3 monthsn post-o

t t r f e o serves as his or her own control; this type of study application was statistically significant sforse nbothce greatly facilitates the interpretation of trials by min- products. However, Cervitec reduced dentine hyper- imising the effects of interpatient variability (Antc- sensitivity (P < 0.001) to tactile stimuli (90.9%) to zak-Bouckoms et al, 1990). Duran and Sengun a significantly greater extent than did Gluma Desen- (2004) compared the long-term effectiveness of sitizer (50.08%). The desensitising effects were five desensitising products (Fluoline varnish, sustained for at least 3 months in both varnish Health-Dent desensitiser, Single Bond, Protect Lin- groups. Similar results were found with the thermal er F and Gluma Desensitizer) and demonstrated (69.2% and 40.8%) and evaporative stimuli (74.5% that at the end of the 3-month evaluation period, all and 57.2%) for the CHX and glutaraldehyde desen- desensitisers showed lower VAS sensitivity values sitiser, respectively, at 3 months. The results show compared with baseline. that both varnishes are effective in the treatment of Presently, there is no agent or product for sensi- dentine hypersensitivity. However, it may be specu- tive teeth that can be considered as a standard and lated that the superior results obtained with the used as a positive control. However, Ide and Morel CHX varnish may be attributed to the antimicrobial (1998) suggested that a dentine bonding agent con- effect of chlorhexidine, which may prevent adsorp- taining HEMA and polycarboxylic acid (Scotch Bond tion and adhesion of bacteria (Schiott and Briner, multi-purpose dentine bonding agent) may be consid- 1976a). This further elucidates the role of plaque ered as a gold standard and thus be used for both and plaque control in the etiology and natural re- the assessment of techniques for estimating cervi- parative process of dentine hypersensitivity. cal sensitivity and for investigating the efficacy of The probable mechanism of the desensitising professionally applied topical desensitising agents. action of CHX varnish could also be explained by In this study, dentine hypersensitivity was evalu- the hypothesis given by Arends et al in 1993, who ated in the patients by using tactile, cold and evap- demonstrated that the chlorhexidine-containing var- orative stimuli; these are the recommended param- nish could penetrate 35 μm into a lesion of about eters for any clinical trial on dentine hypersensitivity 85 μm, which resulted in partial or complete seal- and conform to the guidelines as laid down by Hol- ing of the dentinal tubules. This might be valuable land et al (2002). A scratchometer (Kleinberg and with respect to caries prevention and treatment of Kaufman, 1990) was also used to evaluate the hy- dentine hypersensitivity. persensitivity in the patients using a tactile stimu- The results of the present study conform to the lus. It is a hand-held scratch device, which consists hydrodynamic theory, which assumes that a stimu- of a torsion gauge and a sharp, explorer-like probe. lus applied on the dentine surface causes move- The device is capable of easy movement across a ment of tubular fluid which, in turn activates mecha- sensitive tooth and has an indicator, displayed by noreceptor nerves, eliciting pain and discomfort the arm of the explorer tine, that records the force (Brannstrom and Astrom, 1964). According to this of displacement in centi-Newtons. As recommend- theory, if the functional radius of the opened den- ed by Gillam and Newman (1993), the least severe tinal tubules decreases, then the permeability is stimulus (tactile stimuli) was applied first. An in also decreased, reducing dentine hypersensitivity. vitro study by Camps et al (2003) showed that the Thus, treatment for hypersensitivity should occlude dentinal grooves made by a probe under clinically dentinal tubules and prevent nerve sensitivity. Most relevant forces were between 20 and 30 μm wide; of the dentinal tubules can be obliterated on the they speculated that air blasts tend to overestimate surface and/or occluded within the tubule orifices. the degree of dentine hypersensitivity, as air blasts However, superficial occlusion of tubules can be re- evaporate fluid from 10 to 20 mm2 of cervical den- moved by daily tooth brushing, dissolution of the tine, while scratching would only stimulate about 1 precipitates promoted by saliva, or consumption of to 2 mm2 of dentine, depending on the depth and acidic beverages, leading to short-term sensitising length of the scratch. Keeping the above facts in effects. SEM studies have shown that after applica- mind, the present study was designed to include tion of glutaraldehyde desensitiser, an approxi- tactile stimulus using a scratchometer, which re- mately 1-μm-thick layer was observed covering the corded the forces required to elicit a painful re- treated surfaces. The majority of dentinal tubules sponse over a range of 10 to 100 g. were obliterated with a coating that covered the sur-

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6. Arends J, Ruben JL. Chlorhexidine release by dentine afterb y face and infiltrated into the tubules as plugs (Ar- varnish treatment. Caries Res 1993;27:231-232.Q

u rais, 2004). 7. Banoczy J. Dentine hypersensitivity: General practice con-N

Since the present study was conducted at one siderations for successful management.n Int Dental o J

t t r f e o center, there is a need to validate the results by 2002;52:366-396. ssence comparing them with multicenter clinical trials and 8. Brannstrom M, Astrom M. A study on the mechanism of pain elicited from the dentine. J Dent Res 1964;43:216-221. a longer evaluation period to evaluate other bene- 9. Arrais CAG. Effects of desensitizing agents on dentinal tu- fits (e.g. plaque inhibition) of these varnishes which bule occlusion. J.Appl Oral Sci 2004;12:144-148. were not in the scope of this study. Another phe- 10. Dowell P, Addy M. Dentine hypersensitivity. Etiology, differen- nomenon which may have occurred is the placebo tial diagnosis and management. Braz Dent J 1985;158: effect (Addy and West, 2007). This may raise fur- 92-96. ther questions about the reliability of the evaluation 11. Duran I, Sengun A.The long-term effectiveness of five current desensitizing products on cervical dentine sensitivity. J parameters we employ in dentine hypersensitivity. 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