The Efficacy of Three Desensitizing Agents Used to Treat Dentin Hypersensitivity

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The Efficacy of Three Desensitizing Agents Used to Treat Dentin Hypersensitivity Ugur Erdemir, Esra Yildiz, Imren Kilic, Taner Yucel and Sevda Ozel JADA 2010;141(3):285-296 10.14219/jada.archive.2010.0162 The following resources related to this article are available online at jada.ada.org (this information is current as of June 28, 2014): Updated information and services including high-resolution figures, can be found in the online version of this article at: http://jada.ada.org/content/141/3/285

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The efficacy of three desensitizing agents used to treat dentin hypersensitivity Ugur Erdemir, DDS, PhD; Esra Yildiz, DDS, PhD; Imren Kilic, MS; Taner Yucel, DDS, PhD; Sevda Ozel, PhD, MD

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✷ ✷ Background. In a single-center, double-masked, ® split-mouth–designed, clinical short-term trial, the authors assessed the clinical responses of teeth with N C dentin hypersensitivity (DH) after treating the teeth U U IN G ED A 2 with one of three desensitizing agents across four RT ICLE weeks. Methods. The authors selected 131 teeth with DH in 11 participants. The authors assessed DH of the teeth by using tactile stimuli and air stimuli and had the participants record the level of sensitivity by means of a visual analog scale (VAS). The authors then treated the teeth with one of three desensitizing agents (Pain-Free [Parkell, Edgewood, N.Y.], BisBlock [Bisco, Schaumburg, Ill.], Seal & Protect [Dentsply DeTrey, Konstanz, Germany]) that they applied according to the manufacturers’ instructions. The authors used a split-mouth–designed study in which the teeth in different quadrants of the participants’ mouths received different desensitizing agents. The authors also conducted DH evaluations at 10 minutes after treatment and at one, two, three and four weeks. The authors analyzed data statistically by using Mann-Whitney U and Kruskal-Wallis tests. Results. The results of the statistical analysis showed that all VAS scores at the posttreatment evaluation periods were reduced significantly compared with those at baseline (P < .05). More teeth were sensitive to air stimuli than to tactile stimuli. The mean VAS scores for DH in the mandibular teeth were significantly higher than for those in maxillary teeth immediately after treatment (for tactile stimuli) and two weeks after the first application (for air stimuli) (P < .05) Conclusions. All three desensitizing agents were effective in relieving DH up to four weeks, independent of their application procedures. There was, however, a significant reduction in mean sensitivity scores of teeth that had been treated with Seal & Protect and Pain-Free compared with those of BisBlock at weeks two, three and four. Clinical Implications. The study results should be considered with caution, as it is not clear how many of the pain relief effects were related to the natural desensitization of teeth over time. Key Words. Dentin hypersensitivity; desensitizing agents; visual analog scale. JADA 2010;141(3):285-296. I

Dr. Erdemir is an assistant professor, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, 34093 Capa, Istanbul, Turkey, e-mail “[email protected]”. Address reprint requests to Dr. Erdemir. Dr. Yildiz is a professor, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University. Ms. Kilic is a doctoral student, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University. Dr. Yucel is a professor and the chair, Department of Operative Dentistry, Faculty of Dentistry, Istanbul University. Dr. Ozel is an assistant professor, Department of Biostatistics and Medical Informatics, Faculty of Medicine, Istanbul University.

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ABSTRACT CON

entin hypersensitivity (DH) is a common clinical condition that is experienced by 10 to 20 percent of the general population.1 The Canadian Advisory Board on Dentin Hypersensitivity has defined DH as a sharp, but transient pain arising from exposed dentin in response to thermal, osmotic, tactile or chemical stimuli that cannot be attributed clearly to any other type of defect.2 There are various etiologic and predisposing factors for DH. Dentin sensitivity may arise as a result of enamel loss, root surface denudation of the underlying dentin or both. Enamel loss may result from abfraction, abrasion, erosion or stripping of the root surface caused by gingival recession or periodontal treatment. Several theories have been introduced to characterize DH, and the hydrodynamic theory proposed by Brännström3 is the most widely accepted. According to this theory, either an inward or outward move-

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ment of fluid within the dentin tubules is respontested was that all desensitizing agents would sible for the stimulation of receptors in the pulpal reduce DH by the end of a four-week evaluation dentinal area, resulting in the generation of pain period, regardless of the material used and its impulses. The flow of dentinal fluid is affected by application procedure. the configuration of tubules, the tubule diameter PARTICIPANTS, METHODS AND and the number of open tubules.4 MATERIALS Evaluating a patient’s response to stimulation is a critical part of quantifying his or her oral senParticipants. We recruited 11 participants who sitivity. To help manage DH successfully, patients responded positively to intraoral testing for DH in can record their subjective responses to stimuli the Department of Operative Dentistry, Faculty of such as a cold air blast or a probe on a visual Dentistry, Istanbul University, for a single-center, analog scale (VAS), and then practitioners can catdouble-masked trial using a split-mouth–designed egorize the patient’ sensitivity as slight, moderate, study. Our other inclusion criteria were that the or prolonged or severe.5 participants be in good general health, be at least The goal of treating DH is the immediate and 20 years old and have at least three teeth in three permanent cessation of pain. Treatment can be different quadrants of their mouths that were office- or home-based according to the practisensitive to tactile or air stimuli with a score of at tioner’s and the patient’s delivery and therapeutic least two assessed by means of a VAS (as aims. The therapeutic aims of office- and homedescribed below). based treatments are to interrupt the pulpal We excluded patients from the study if they neural response or to block the sensitive mechamet any of the following criteria: had a known nisms through tubule occlusion. Many treatments allergy to any of the ingredients in the treatment to occlude dentin tubules and materials used, were receiving periodontal therapy or had received reduce the level of DH have The goal of treating nonsurgical periodontal treatment been proposed.5-8 Clinical studies dentin hypersensitivity within the previous three months, have been conducted to deteris the immediate were receiving anti-inflammatory mine the treatment material or tricyclic antidepressant agents that should be used and the and permanent and analgesic medication, had most effective treatment cessation of pain. received antibiotic therapy within method.5,7-11 However, varying the last six months, were pregnant results were reported, which or lactating, had dentures, had any active cervical were attributed to different results obtained from caries or deep abrasions requiring Class V fillthe placebo groups and patients’ progressively ings, or had any fractured or endodontically improved oral hygiene habits owing to the treated teeth or teeth with large restorations. Hawthorne effect.7,8 Tubule-blocking agents—including fluoride We provided participants with detailed inforsolution, oxalate-containing resin and resin-based mation, both orally and in written form, about the desensitizers precipitating protein—have been principles of treatment and purpose of the study. introduced as dentin desensitizers.9,12-14 The use of We also informed the participants about the posadhesive materials is another method that can be sible causes and the multifactorial origin of DH used to seal dentin tubules and reduce dentin and asked them to contact to the lead researcher sensitivity. The results of clinical studies have (U.E.) if they experienced any adverse reactions shown significant reductions in sensitivity after to the treatment. All of the participants received dentin adhesives have been used.15-17 The results and signed the appropriate informed consent of in vivo studies have confirmed the efficacy of forms. The Ethical Committee of Istanbul Univeroxalate- and resin-based treatments.5,9,14,18-21 sity, Faculty of Medicine, approved the study proWe conducted a study to assess the efficacy of tocol (project 2007/795). two oxalate-based desensitizing agents and a Treatment procedure. We cleaned 131 sensi2-hydroxyethyl methacrylate– (HEMA-) free tive teeth in the 11 participants (one to six teeth desensitizing agent containing fluoride to provide short-term pain relief for DH and to help cliniABBREVIATION KEY. DH: Dentin hypersensitivity. cians choose the most effective and rapid treatHEMA: 2-hydroxyethyl methacrylate. IAT: Immediately after treatment. ment solution for DH. The null hypothesis we 286

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TABLE 1

Desensitizing agents used in the study and their application procedures. TEST GROUP

LOT NUMBER

CONTENTS

Pain-Free (Parkell, Edgewood, N.Y.)

Liquid A: MM3

Emulsion of poly(methyl methacrylate)-co-pstyrenesulfonic acid polymer

Liquid B: MR1

2% oxalic acid solution

BisBlock (Bisco, Schaumburg, Ill.)

0600009983

Oxalic acid

Total-etch for 15 seconds, rinse and dry, apply BisBlock for 30 seconds, rinse and leave moist, apply One-Step (Bisco), light cure for 10 seconds, apply the second coat of One-Step

Seal & Protect (Dentsply DeTrey, Konstanz, Germany)

0611001783

Dipentaerythritol penta acrylate monophosphate), nanofillers, triclosan, acetone, cetylamine hydrofluoride (resin-based material)

Apply for 20 seconds, volatilize the acetone with a gentle stream of air, light cure for 10 seconds, apply the second coat and light cure

in each quadrant) with moist cotton pellets and dried them with cotton rolls. We then subjected the teeth to tactile stimuli by drawing a dental explorer across the cervical area of each tooth at a relatively constant mild force10 to determine the participant’s baseline tactile response. Approximately 10 minutes later, we isolated the sensitive tooth from the adjacent teeth mesially and distally by using cotton rolls and applied an operatorcontrolled thermal stimulus (45 pounds per square inch, 19 ± 5°C) 1 centimeter from the cementoenamel junction of the sensitive tooth for one to two seconds by means of an air syringe to determine the participant’s baseline thermal response. Then we cleaned the teeth with moist cotton pellets and dried them with cotton rolls and isolated the operation field by means of cotton rolls and suction. One researcher (I.K.), who did not know the baseline sensitivity values for the teeth, applied Pain-Free (Parkell, Edgewood, N.Y.), BisBlock (Bisco, Schaumburg, Ill.) and Seal & Protect (Dentsply DeTrey, Konstanz, Germany) desensitizing agents to the teeth according to the manufacturers’ instructions (Table 1). Before opening the bottles of desensitizing agents, she shook them vigorously for 10 seconds. The teeth in the different quadrants of each participant’s mouth received different desensitizing agents; the adjacent teeth received the same treatment. She used a split-mouth study design in which she randomly selected which agent would be applied in which quadrant; she did not use a randomization list. The researcher recorded the assignment of teeth to the treatment groups but did not reveal

APPLICATION PROCEDURE Mix one drop each of the two Pain-Free components and apply with a cotton pellet for 30 seconds, air dry for 5 to 10 seconds, and reapply for 30 seconds to the sensitive surfaces

this information to the other researchers or the participant until the end of the study. We performed the follow-up examinations using the same tactile and air stimuli as we did at baseline, and we used the same protocol to obtain data at baseline, immediately after treatment (IAT) (at 10 minutes) and at one, two, three and four weeks. During the four-week evaluation period, all of the participants used the same standard dentifrice (Parodontax, Ali Raif Ilac Sanayi, Istanbul) that did not have any antihypersensitivity ingredients and their own manual toothbrush. In addition, during the four-week evaluation period, we asked participants to not use any antihypersensitivity products such as mouthwashes. We did not include a placebo group in our study for ethical reasons. At the outset of the study, each participant received a single application of a desensitizing agent and received no further treatment at subsequent visits. Recording sensitivity. We subjectively assessed participants’ teeth by means of a VAS. The VAS was a 10-cm line with the anchor words “no pain” (0 cm) and “intolerable pain (10 cm)” at the opposite ends. We asked each participant to place a vertical mark on the VAS to indicate the intensity of his or her level of sensitivity after receiving stimuli. One researcher (U.E.), who did not know which material had been applied to each tooth, determined the sensitivity scores. He quantified each participant’s response by measuring the distance in centimeters from the first anchor words (no pain) to the mark.8 The study’s duration was four weeks. Within this period, we JADA, Vol. 141

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%

First Quadrant

6

Second Quadrant

We set the significance level at α = .05. RESULTS

5

The 11 participants (seven women and four men) ranged in age from 2 32 to 72 years old (mean 1 age, 47 ± 12 years 0 standard deviation [SD]). 6 5 4 3 2 1 1 2 3 4 5 6 The 131 teeth we tested 0 at baseline were incisors 1 (54), canines (24), premo2 lars (41) and first molars 3 4 (12). The distribution of 5 the teeth according to 6 quadrant is shown in 7 Figure 1. Not all of the test teeth had been restored. Fourth Quadrant Third Quadrant The mean VAS scores for the three treatment Figure 1. Distribution of all hypersensitive teeth (one to six in each quadrant) included in the study. groups after receiving tactile and air stimuli are presented in Tables 2 and 3, respectively. The evaluated the teeth for sensitivity at six data colmean ± SD baseline DH scores for the teeth (ranlection points: before treatment (baseline), IAT, domly divided into three groups) were as follows: and at weeks one, two, three and four. At each group 1 (tactile, 2.41 ± 2.96; air, 3.34 ± 2.55), data collection point, we used new data sheets so group 2 (tactile, 3.61 ± 3.47; air, 5.14 ± 3.05) that neither the researcher who obtained the and group 3 (tactile, 4.35 ± 3.61; air, 5.37 ± 3.19). measurement nor the participant would see the Afterward, we applied Pain-Free to the teeth in data from the earlier collection points. group 1, Seal & Protect to the teeth in group 2 Statistical analysis. We used teeth, rather and BisBlock to the teeth in group 3. At baseline, than participants, as the statistical units to compare the effectiveness of the desensitizing agents. the mean sensitivity score of the teeth in the In our study, we expressed the descriptive statisPain-Free group was significantly lower than that tics as mean ± standard deviation (SD) (based on of the teeth in the Seal & Protect and BisBlock the 10-cm VAS). We used the Kolmogorov-Smirnov groups. However, after we applied the desensitest to check the normal distribution of data. As the tizing agents, we found that all VAS scores from means of groups did not demonstrate normal distrithe posttreatment evaluation periods were signifibution, we analyzed the differences between the cantly lower for both tactile and air stimuli comthree treatment groups by using Kruskal-Wallis pared with the baseline data (P < .05). one-way analysis of variance. We used the MannTo overcome the individual effects of baseline Whitney U test to conduct pairwise comparisons. In VAS scores, we calculated decreases in VAS scores addition, we used the Wilcoxon signed rank test to at subsequent evaluation periods as the percentage determine the differences between participants’ ratio of change in VAS score from pretreatment to responses to each material at baseline and after four treatment (Tables 4 and 5, page 290). IAT, the weeks. To overcome the individual effects of baseVAS scores decreased significantly compared with line VAS scores on the subsequent evaluation baseline for all three desensitizing agents in periods, we expressed changes in VAS scores response to both tactile and air stimuli (P < .05). obtained after treatment as percentages compared The differences among VAS scores in all treatment with pretreatment VAS scores. We used commergroups increased at the one-week evaluation in cially available software (SPSS 11.0 for Windows, response to air stimuli. There was a significant SPPS, Chicago) to perform the statistical analyses. reduction in mean sensitivity scores in response to 4

No. of Teeth

3

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TABLE 2

The mean VAS* scores for the three treatment groups after receiving tactile stimuli across four weeks. PAIN-FREE† (N = 44) (MEAN VAS SCORE [CENTIMETERS ± SD‡])

SEAL & PROTECT† (N = 44) (MEAN VAS SCORE [CM ± SD])

BISBLOCK† (N = 43) (MEAN VAS SCORE [CM ± SD])

χ2

P§

Baseline

2.41 ± 2.96

3.61 ± 3.47

4.35 ± 3.61

6.645

.036

Immediately After Treatment (10 Minutes)

0.68 ± 1.65

0.75 ± 1.20

1.30 ± 2.21

4.288

.117

Week 1

1.00 ± 2.09

0.80 ± 1.44

1.26 ± 1.90

2.846

.241

Week 2

0.36 ± 1.01

0.91 ± 1.75

0.74 ± 1.44

2.366

.306

Week 3

0.34 ± 0.86

0.68 ± 1.30

0.56 ± 1.27

2.329

.312

Week 4

0.27 ± 0.69

0.43 ± 1.22

0.65 ± 1.42

0.992

.609

DATA COLLECTION POINT

* † ‡ §

VAS: Visual analog scale. Materials’ manufacturers are listed in Table 1. SD: Standard deviation. Kruskal-Wallis test. The posttreatment VAS scores of all groups treated with desensitizing agents were lower than baseline VAS scores.

TABLE 3

The mean VAS* scores for the three treatment groups after receiving air stimuli across four weeks. PAIN-FREE† (N = 44) (MEAN VAS SCORE [CENTIMETERS ± SD‡])

SEAL & PROTECT† (N = 44) (MEAN VAS SCORE [CM ± SD])

BISBLOCK† (N = 43) (MEAN VAS SCORE [CM ± SD])

χ2

P§

Baseline

3.34 ± 2.55

5.14 ± 3.05

5.37 ± 3.19

12.124

.002

Immediately After Treatment (10 Minutes)

1.91 ± 2.55

1.86 ± 2.41

2.63 ± 2.72

1.793

.408

Week 1

2.07 ± 2.77

2.32 ± 2.37

3.42 ± 3.18

5.827

.054

Week 2

1.43 ± 2.06

1.84 ± 1.92

2.93 ± 2.32

11.161

.004

Week 3

1.36 ± 1.80

1.32 ± 1.39

2.37 ± 2.02

10.593

.005

Week 4

1.18 ± 1.96

0.80 ± 1.28

2.00 ± 1.83

17.923

.0001

DATA COLLECTION POINT

* † ‡ §

VAS: Visual analog scale. Materials’ manufacturers are listed in Table 1. SD: Standard deviation. Kruskal-Wallis test. The posttreatment VAS scores of all groups treated with different desensitizing agents were lower than baseline VAS scores.

air stimuli in the Pain-Free (71.09 ± 37.71 percent) and the Seal & Protect (86.18 ± 21.24 percent) groups compared with the BisBlock group (47.74 ± 66.42 percent) at week four (P < .05). At the end of four-week evaluation period, however, we noted lower VAS scores for all three groups compared with at baseline. Figures 2 and 3 (page 291) show the changes in VAS scores in response to both tactile and air stimuli over time for each group. Within the treatment group comparisons, the results of the Kruskal-Wallis test showed that participants in all groups were significantly more sensitive to air than to tactile stimuli at all data collection points (P < .0001). The results of post hoc analyses for pairwise comparisons showed that the alleviative effects of desensitizing agents

were significantly different for Pain-Free (P < .05) and that there were no significant differences between Seal & Protect and BisBlock (P > .05). Table 6 (page 292) shows variations in the participants’ responses according to treatment group at baseline and at four weeks. The Kruskal-Wallis test results showed that differences between the VAS scores at baseline and after four weeks were significant for all three treatment groups in response to air stimuli (P < .05), whereas there were no significant differences in response to tactile stimuli (P = .082). The mean VAS score in the mandibular teeth was significantly higher than that in the maxillary teeth IAT in response to tactile stimuli and at two weeks in response to air stimuli (P < .05) (Table 7, page 292). During the JADA, Vol. 141

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TABLE 4

Decreases in the mean visual analog scale scores of the groups treated with different desensitizing agents in subsequent evaluations for air stimuli compared with baseline data. PAIN-FREE* (N = 44) (MEAN DECREASE [% ± SD†])

BISBLOCK* (N = 43) (MEAN DECREASE [% ± SD])

SEAL & PROTECT* (N = 44) (MEAN DECREASE [% ± SD])

P‡

Immediately After Treatment (10 Minutes)

50.79 ± 60.11a§

47.88 ± 67.16a

71.87 ± 29.98a

.324

Week 1

43.86 ± 65.04a

17.72 ± 128.23a

58.86 ± 39.11a

.155

Week 2

56.32 ± 71.36

a

a

.027

Week 3

54.54 ± 71.02ab

50.26 ± 67.77a

77.05 ± 22.59b

.010

b

a

DATA COLLECTION POINT

Week 4 * † ‡ §

71.09 ± 37.71

a

21.49 ± 30.40

47.74 ± 66.42

b

64.38 ± 38.49

86.18 ± 21.24

.0001

Materials’ manufacturers are listed in Table 1. SD: Standard deviation. Kruskal-Wallis test. The mean VAS scores were expressed as percentages with respect to baseline data. Different superscript letters in a column represent statistically significant differences (P < .05).

TABLE 5

Decreases in the mean visual analog scale scores of the groups treated with different desensitizing agents in subsequent evaluations for tactile stimuli compared with baseline data. PAIN-FREE* (N = 44) (MEAN DECREASE [% ± SD†])

BISBLOCK (N = 43) (MEAN DECREASE [% ± SD])

SEAL & PROTECT (N = 44) (MEAN DECREASE [% ± SD])

P‡

Immediately After Treatment (10 Minutes)

41.13 ± 82.69a§

47.74 ± 66.42a

53.36 ± 61.74a

.928

Week 1

33.75 ± 67.06a

48.04 ± 54.32a

55.58 ± 49.64a

.321

Week 2

54.12 ± 60.22

a

a

59.92 ± 60.31

53.87 ± 54.32

a

.694

Week 3

56.81 ± 51.61a

65.17 ± 54.95a

57.00 ± 53.57a

.398

Week 4

a

a

a

.570

DATA COLLECTION POINT

* † ‡ §

53.75 ± 56.19

63.75 ± 51.54

64.31 ± 50.37

Materials’ manufacturers are listed in Table 1. SD: Standard deviation. Kruskal-Wallis test. The mean VAS scores were expressed as percentages with respect to baseline data. The same superscript letters in a column represent no statistically significant difference.

four-week evaluation period, no adverse events such as an allergic reaction were reported for any of the ingredients in the desensitizing agents. DISCUSSION

The results of our single-center, double-masked, split-mouth–designed clinical study showed that all desensitizing agents relatively alleviated DH in response to both tactile and air stimulation within the four-week evaluation period, despite their different chemical compositions and application procedures. Therefore, the null hypothesis of our study—all desensitizing agents would reduce DH at the end of the four-week evaluation period, regardless of the material used and its application procedure—was accepted. 290

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Many treatment modalities and agents have been used to treat DH; however, the efficacy of most of them has varied and not been well established. The subjective nature of DH pain makes objective evaluation of it difficult. In our study, we found that all of the agents tested were effective in reducing DH, as indicated by VAS scores with large SDs, which reflect the subjective nature of pain perception and the variability of responses over time. Such variability in pain response made it difficult to detect significant differences among groups. In addition, this variability may be due more to the number of teeth and less to the randomization of the treatment. We designed the study so that the researcher who applied the desensitizing agents would not know what the

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PERCENTAGE

PERCENTAGE

baseline VAS scores for 100 ▲ ◆ ■ air and tactile stimuli were, so that the three 90 desensitizing agents were 80 applied in the different 70 quadrants and so that ◆ the adjacent teeth 60 ◆ ◆ Pain-Free received the same treat■ ■ 50 ■ BisBlock ment. The reason we did ▲ ◆ ▲ ◆ ▲ ◆ ▲ 40 ▲ Seal & Protect not group the baseline ■ ■ ▲ ■ VAS scores was that the 30 rate of teeth being 20 affected by changes in 10 the participants’ habits (for example, oral 0 Baseline IAT Week 1 Week 2 Week 3 Week 4 hygiene and food intake) would not reach signifiDATA COLLECTION PERIOD cant levels. We assessed the teeth according to the Figure 2. Change in the visual analog scale scores in response to tactile stimuli over time. Pain-Free is manufactured by Parkell, Edgewood, N.Y. BisBlock is manufactured by Bisco, Schaumburg, Ill. Seal & accepted standards in an Protect is manufactured by Dentsply DeTrey, Konstanz, Germany. IAT: Immediately after treatment (at 10 minutes). oral environment and saw that all differences arising from the partici◆ 100 ▲ ■ pants’ habitual practices 90 were insignificant; therefore, we eliminated them ■ 80 ■ to comply with standards. 70 The use of a control group in studies investi60 ◆ Pain-Free ◆ gating DH can be prob■ ■ BisBlock ■ 22 50 ■ ◆ lematic. A negative con◆ Seal & Protect ◆ ▲ trol, in which no treat▲ 40 ▲ ment or placebo treatment 30 ◆ ▲ is received, is an alterna▲ tive; however, researchers 20 ▲ have argued that the use 10 of a negative control is 0 unethical.17 Nevertheless, Baseline IAT Week 1 Week 2 Week 3 Week 4 most guidelines recomDATA COLLECTION PERIOD mend that a negative control be included in clinical Figure 3. Change in the visual analog scale scores in response to air stimuli over time. Pain-Free is manufactured by Parkell, Edgewood, N.Y. BisBlock is manufactured by Bisco, Schaumburg, Ill. Seal & trials that are conducted Protect is manufactured by Dentsply DeTrey, Konstanz, Germany. IAT: Immediately after treatment 22,23 (at 10 minutes). to investigate DH. Zantner and colleagues11 evaluated the effectiveness of a one-time in-office from those of studies in which placebos were used, application of a new agent designed to treat DH by we used neither controls nor placebos in our study, using water as the control in a split-mouth– nor did the authors of clinical trials investigating designed study. They found that there was no difthe use of adhesives for treatment for DH.15-17 ference between the agent and the placebo. These Finally, concerning the reduced DH scores in our results are in contrast to those of studies that used study, an additional true placebo effect should be water as the control, in which investigators taken into consideration. Including a placebo group observed significant differences between the agents in our study might have enabled us to determine and the control.5,10 Because these results differ more clearly whether any of the results obtained JADA, Vol. 141

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TABLE 6

Variations in participants’ responses at baseline and four weeks, according to treatment group. TEST GROUP*

AIR STIMULI (BASELINE-WEEK 4) (MEAN VAS† SCORE [CENTIMETERS ± SD‡])

P§

TACTILE STIMULI (BASELINE-WEEK 4) (MEAN VAS SCORE [CM ± SD])

P§

Pain-Free (n = 44)

2.15 ± 1.76

.0001

2.13 ± 2.71

.0001

Seal & Protect (n = 44)

4.34 ± 2.58

.0001

3.18 ± 3.32

.0001

BisBlock (n = 43)

3.37 ± 2.98

.0001

3.69 ± 3.38

.0001

P¶ * † ‡ § ¶

.001

.082

Materials’ manufacturers are listed in Table 1. VAS: Visual analog scale. SD: Standard deviation. Wilcoxon signed rank test. Kruskal-Wallis test.

TABLE 7

Mean VAS* scores according to the hemiarches in response to air and tactile stimuli. DATA COLLECTION POINT

P†

AIR STIMULI Maxillary Teeth (n = 52) (Mean VAS Score [Centimeters ± SD ‡ ])

Mandibular Teeth (n = 79) (Mean VAS Score [Centimeters ± SD])

Baseline

3.87 ± 2.65

5.10 ± 3.22

Immediately After Treatment (10 Minutes)

2.27 ± 4.14

Week 1

2.17 ± 2.64

TACTILE STIMULI

P†

Maxillary Teeth (n = 52) (Mean VAS Score [Centimeters ± SD])

Mandibular Teeth (n = 79) (Mean VAS Score [Centimeters ± SD])

.045§

2.85 ± 3.00

3.85 ± 3.64

.261

2.29 ± 2.62

.410

0.62 ± 1.54

1.10 ± 1.84

.013§

2.87 ± 2.93

.168

0.98 ± 1.96

1.04 ± 1.74

.604

Week 2

1.37 ± 1.93

2.52 ± 2.23

.002§

0.42 ± 1.22

0.83 ± 1.55

.084

Week 3

1.42 ± 1.82

1.85 ± 1.79

.054

0.31 ± 0.80

0.67 ± 1.33

.133

Week 4

1.21 ± 2.03

1.39 ± 1.60

.055

0.23 ± 0.64

0.59 ± 1.38

.281

* † ‡ §

VAS: Visual analog scale. Mann-Whitney U test. SD: Standard deviation. Statistically significant at P < .05.

were due to a placebo effect. Therefore, the placebo effect should be kept in mind when considering results. Ideally, the evaluation period in our study should have been longer than four weeks; however, we anticipated that the participants would not be compliant after four weeks. The long-term effectiveness of the desensitizing agents needs to be evaluated to test the longevity of their performances and amount of time until DH reoccurs after treatment. Kielbassa and colleagues8 evaluated the effectiveness of two fluoride agents (calcium fluoride and sodium fluoride) in reducing DH in the short term (four weeks) and long term (six and 12 months). They found that the use of these 292

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agents led to a significant reduction in DH within four weeks and resulted in constantly low sensitivity scores in the long term (six-12 months) compared with the baseline data. As the goal of our study was to determine which agents would eliminate the participant’s acute complaints of DH rapidly and effectively, we decided to conduct a short-term (four-week) study. It is important, however, that studies be carried out to determine which agents provide long-term relief from DH. To determine the participants’ sensitivity levels in our study, we translated the subjective feedback to both tactile and air stimuli into objective data using VAS, which is the most appropriate method to use to diagnose pain levels.

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To assess pain, we used more than one stimulus The results of our short-term, double-masked, as recommended by Holland and colleagues.22 Their split-mouth–designed clinical study showed that recommendation arose from the fact that different all three agents reduced the level of DH experistimuli can elicit different pain sensations. All enced by participants significantly IAT and maindental lesions are investigated by using a probe tip tained the reduced levels of DH for at least four as a tactile stimulus, which causes the inward weeks even when we evaluated the teeth using movement of the dentinal fluid owing to the comair and tactile stimuli. We also noted that all pression of the dentin. Thus, mechanoreceptors three desensitizing agents relatively alleviated causing the painful sensation are activated.24 Air DH within the four-week evaluation period stimulus decreases the temperature at the dentin despite their different chemical compositions and surface, causes a rapid outward fluid flow from application procedures. opened dentin tubules, which stimulates the Pain-Free is an oxalic acid–containing desensipainful sensation.25 For these reasons, we used a tizing agent that reacts with ionized calcium within standard dental explorer as a tactile stimulus and the dentin tubule and forms insoluble calcium blasts of air as an evaporative stimulus. The results oxalate crystals.18 In addition, Pain-Free contains a of both the tactile and air evaluations showed a poly(methyl methacrylate)-co-p-styrenesulfonic acid trend toward an immediate reduction in sensitivity; polymer (90 percent poly[methyl methacrylate] and however, the use of air stimuli resulted in signifi10 percent p-styrene sulfonic acid) that provides a cantly higher VAS scores in all treatment groups. sealing surface film on the tooth. The oxalate preThis difference in sensitivity scores cipitates are thought to be sealed between the two stimuli may be beneath the polymer film, thereby All three desensitizing due to the fact that dentin area providing desensitization. Zhang exposed to scratching was too and colleagues28 found that Painagents relatively small compared with the dentin Free reduced in vitro dentin peralleviated dentin area exposed to air blast, and that meability and covered the dentin hypersensitivity within air blasts tend to lead to an oversurface with resin completely. It the four-week estimation of the degree of DH. formed a thin resin layer that evaluation period The loss of enamel, cementum sealed dentin tubules long enough despite their different or both owing to gingival recesto permit the natural successive sion is the main cause of DH. physicochemical reactions to chemical compositions Study investigators have reported occlude the tubules and to mainand application the widespread prevalence of tain the desensitization.28 Morris procedures. 1,26 DH. The dentin tubules must and colleagues9 reported that be open to the oral cavities of Pain-Free effectively reduced DH people who experience DH. To relieve DH, after a single application and that this effect was various therapeutic models and agents are recommaintained for three months. Our data were in mended, which makes it challenging for practiagreement with their results regarding the immetioners when they are selecting the appropriate diate relief of DH. therapy for patients. Practitioners can choose BisBlock is an oxalate-based desensitizing between two treatment options: sealing and agent consisting of low concentrations of oxalic occluding the dentin tubules, thereby blocking the acid that react with tooth minerals and obstruct hydrodynamic mechanism; and blocking neural the dentin tubules. Application of oxalate matetransmission at the pulp level. The blockage of rials to the exposed dentin results in precipitation neural transmission theoretically can be achieved of potassium oxalate crystals, occlusion of open by using topically applied potassium salts. The tubules in cervical dentin and instant sclerosis of former can be achieved by physically blocking the the tubules.19 The oxalate crystals in the agent dentin tubules by using three different active react with calcium in the tooth to form insoluble ingredients found in desensitizing agents: ion or calcium oxalate crystals.27 27 salts, protein-amino acid precipitates and resins. Gillam and colleagues20 conducted an in vitro Therefore, we evaluated the effectiveness of three study and found that professionally applied indifferent desensitizing agents (a resin-based office products that contain oxalate are able to dentin sealer and two oxalate-containing desensicover the dentin surface, occluding the tubules or tizing agents) in treating participants with DH. both to varying degrees. Pashley29 used these JADA, Vol. 141

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agents in the form of solutions or as resin-free HEMA-free Seal & Protect contains a mixture of gels that consisted of high concentrations of oxalic dimethacrylate resins in acetone as a solvent, as acid.29 The results of studies showed that oxalate well as triclosan and fluoride. Seal & Protect is a salts are effective19,30; however; these crystals are self-adhesive, light-curing, translucent material that either partially dissolved in oral fluids or lost seals the open dentin tubules in teeth with DH. during toothbrushing.20,31 Baysan and Lynch14 conducted an in vivo study In contrast to other oxalate desensitizing agents, in which they applied five increments of Seal & BisBlock’s technique is that the total-etch proProtect. They found that Seal & Protect was effeccedure is performed before the oxalate and adhesive tive in reducing DH after three months and that are placed.32 This technique provides long-lasting this effect was maintained across 19 months. In effects owing to the removal of mineral from the our study, we applied Seal & Protect in two layers reactive surface and the formation of oxalate crysaccording to the manufacturer’s instructions, and tals deep within the dentin tubules, as opposed to we observed that it was effective during all test other techniques using oxalate-containing products periods, as were the other desensitizing agents. in which crystal formation occurs only on the surWe speculate that this may have been related to face of the tubules. Pashley and colleagues,33 howthe hydrophilic resin and an additional conever, found that the surface layer of acid-resistant stituent, such as fluoride. Seal & Protect may act calcium oxalate crystals interfered with resin infilas a self-etching primer and demineralize and seal tration through the demineralized collagen the dentin by forming a thick and long-lasting matrices, which resulted in poor layer in combination with fluoride. bonding of total-etch adhesives to The etching of the dentin provided The rationale for by these formulations may ensure oxalate-treated dentin. In our the use of resins, a resistant hybridized layer and study, we used a total-etch dentin resin tags. The resin layer may act adhesive One-Step (Bisco) that dentin-bonding agents as a mechanical barrier protecting formed a thin and weak adhesive or both to treat dental the tubule fluid from displacement layer, which could not withstand hypersensitivity is to during the application of tactile mechanical forces and dissolution create resin plugs or and air stimuli. When using Seal & into oral fluids and which may resin tags that physically Protect to eliminate DH, clinicians have accounted for resin and calclose the open dentin must consider the potential role of cium oxalate removal even if we the fluoride in its composition. used two coats of bonding agent to tubules and completely Even though the adhesive covering cover sensitive areas. DH, howseal orifices. (realized in time with Seal & Proever, was not reversed completely in teeth treated with BisBlock, tect containing fluoride in conand BisBlock’s effectiveness in reducing sensitivity tradistinction with the components of the other was lower than that of Seal & Protect and Painproducts used in the study) may deteriorate, we Free with air stimuli across four weeks. believe that the effects of the fluoride may be long Dental professionals also use derivatives of lasting. dentin-bonding agents to treat DH. Investigators When considering the effectiveness of the two of several studies have reported successful results oxalate-containing desensitizing agents and a with dentin-bonding systems, even though these HEMA-free desensitizing agent used in this study, systems were not designed to treat DH only.16,17,21,34 clinicians should take a phenomenon usually assoSensitive dentin is characterized by open ciated with clinical investigations into account.8 dentin tubules that are free of debris and have Patients who participate in clinical studies someprecipitation inside the lumen of the tubules.29,35,36 times progressively improve their oral hygiene, a The experimental rationale for the use of resins, phenomenon called the Hawthorne effect. The dentin-bonding agents or both to treat DH is to improvement of the participants’ oral hygiene create resin plugs or resin tags that physically habits could have beneficial effects on DH and close the open dentin tubules and completely seal might lead to occluded tublues.38 To prevent the 37 orifices. Haywood reported that dentin-bonding participant from being affected by the Hawthorne agents sealed the exposed dentin tubules and effect during the course of the treatment, we told immediately blocked the transmission of paineach participant to use only dentifrice without producing stimuli to pulpal nerves. antihypersensitivity ingredients and not to use 294

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any other antihypersensitivity products. The therapeutic effect of any DH treatment can be questioned, since it generally is accepted that in many patients this kind of discomfort will decrease over time without any treatment. This cessation of discomfort can be due to natural occlusion of dentin tubules, a decreased number of patent tubules, an increased incidence of reparative dentin39,40 or to seasonal changes.41 When considering the outcomes of our study, we assume that at least some of these possible effects could be true, because we gave all of the participants educational advice, and predisposing habits leading to increased DH might have been modulated, thus preventing the recurrence of DH.42 Rees and colleagues43 conducted a study of the intraoral distribution of DH and found that mandibular incisors, followed by the premolars and molars were the most commonly affected teeth. Taani and Awartani44 also reported that mandibular anterior teeth were among the tooth types that were affected most. The results of our study were consistent with those of these studies39,43 in that DH is observed more frequently in mandibular teeth than in maxillary teeth and that proportionately more teeth are sensitive to air stimuli than to tactile stimuli. Significant differences in our study between the maxillary and mandibular teeth both IAT and two weeks after the first application may be due to difficulties in the isolation of the treatment area in mandibular hemiarches. Nevertheless, we observed decreases in sensitivity in all groups and found no significant differences at subsequent observation periods in response to either form of stimulus. CONCLUSIONS

The results of this short-term study showed that all three desensitizing agents effectively reduced DH after a single application for up to four weeks under clinical conditions. The sensitivity scores were significantly lower for the Seal & Protect and Pain-Free desensitizing agents in response to air blast stimuli at two, three and four weeks than were those for the BisBlock desensitizing agent. The results of our study, however, should be considered with caution, as it is not clear how many of the pain relief effects were related to the natural desensitization of teeth over time. Therefore, when evaluating our results, it should be kept in mind that we did not use placebos in our study. The significant difference in the degree of DH reduction at four weeks in teeth treated with

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Seal & Protect and Pain-Free suggests the need for a long-term study to facilitate better understanding of the performance of these desensitizing agents. ■ Disclosure. None of the authors reported any disclosures. 1. Addy M. Dentin hypersensitivity: definition, prevalence, distribution aetiology. In: Addy M, ed. Tooth Wear and Sensitivity Clinical Advances in Restorative Dentistry. London: Martin Dunitz; 2000:239-248. 2. Canadian Advisory Board on Dentin Hypersensitivity. Consensusbased recommendations for the diagnosis and management of dentin hypersensitivity. J Can Dent Assoc 2003;69(4):221-226. 3. Brännström M. Sensitivity of dentine. Oral Surg Oral Med Oral Pathol 1966;21(4):517-526. 4. Brännström M. The hydrodynamic theory of dentinal pain: sensation in preparations, caries, and the dentinal crack syndrome. J Endod 1986;12(10):453-457. 5. Pamir T, Dalgar H, Onal B. Clinical evaluation of three desensitizing agents in relieving dentin hypersensitivity. Oper Dent 2007;32(6):544-548. 6. Ritter AV, de L Dias W, Miguez P, Caplan DJ, Swift EJ Jr. Treating cervical dentin hypersensitivity with fluoride varnish: a randomized clinical study. JADA 2006;137(7):1013-1020. 7. Burke FJ, Malik R, McHugh S, Crisp RJ, Lamb JJ. Treatment of dentinal hypersensitivity using a dentine bonding system. Int Dent J 2000;50(1):283-288. 8. Kielbassa AM, Attin T, Hellwig E, Schade-Brittinger C. In vivo study on the effectiveness of a lacquer containing CaF2/NaF in treating dentine hypersensitivity. Clin Oral Investig 1997;1(2):95-99. 9. Morris MF, Davis RD, Richardson BW. Clinical efficacy of two dentin desensitizing agents. Am J Dent 1999;12(2):72-76. 10. Kakaboura A, Rahiotis C, Thomaidis S, Doukoudakis S. Clinical effectiveness of two agents on the treatment of tooth cervical hypersensitivity. Am J Dent 2005;18(4):291-295. 11. Zantner C, Popescu O, Martus P, Kielbassa AM. Randomized clinical study on the efficacy of a new lacquer for dentine hypersensitivity. Schweiz Monatsschr Zahnmed 2006;116(12):1232-1237. 12. Camps J, Pizant S, Dejou J, Franquin JC. Effects of desensitizing agents on human dentin permeability. Am J Dent 1998;11(6):286-290. 13. Swift EJ Jr. Ask the experts: resin desensitizers. J Esthet Dent 1999;11(6):289-290. 14. Baysan A, Lynch E. Treatment of cervical sensitivity with a root sealant. Am J Dent 2003;16(2):135-138. 15. Dondi dall’Orologio G, Lorenzi R, Anselmi M, Opisso V. Dentin desensitizing effects of Gluma Alternate, Health-Dent Desensitizer and Scotchbond Multi-Purpose. Am J Dent 1999;12(3):103-106. 16. Duran I, Sengun A. The long-term effectiveness five current desensitizing products on cervical dentin sensitivity. J Oral Rehabil 2004;31(4):351-356. 17. Ferrari M, Cagidiaco MC, Kugel G, Davidson CL. Clinical evaluation of a one-bottle bonding system for desensitizing exposed roots. Am J Dent 1999;12(5):243-249. 18. Muzzin KB, Johnson R. Effects of potassium oxalate on dentin hypersensitivity in vivo. J Periodontol 1989;60(3):151-158. 19. Camps J, Pashley D. In vivo sensitivity of human root dentin to air blast and scratching. J Periodontol 2003;74(11):1589-1594. 20. Gillam DG, Newman HN, Davies EH, Bulman JS, Troullos ES, Curro FA. Clinical evaluation of ferric oxalate in relieving dentine hypersensitivity. J Oral Rehabil 2004;31(3):245-250. 21. Prati C, Cervellati F, Sanasi V, Montebugnoli L. Treatment of cervical dentin hypersensitivity with resin adhesives: 4-week evaluation. Am J Dent 2001;14(6):378-382. 22. Holland GR, Narhi MN, Addy M, Gangarosa L, Orchardson R. Guidelines for the design and conduct of clinical trials on dentine hypersensitivity. J Clin Periodontol 1997;24(11):808-813. 23. Ad Hoc Advisory Committee on Dentinal Hypersensitivity, Council on Dental Therapeutics. Recommendations for evaluating agents for the reduction of dentinal hypersensitivity. JADA 1986; 112(5):709-710. 24. Pashley DH. Mechanism of dentin sensitivity. Dent Clin North Am 1990;34(3):449-473. 25. Krauser JT. Hypersensitive teeth, part II: treatment. J Prosthet Dent 1986;56(3):307-311. 26. Dababneh RH, Khouri AT, Addy M. Dentine hypersensitivity: an enigma? A review of terminology, epidemiology, mechanisms, aetiology

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