Medical knowledge | Dentistry » Dentine hypersensitivity, a review

Review article Dentine hypersensitivity: a review Collaert B, Fischer C. Dentine hypersensitivity Endod Dent Traumatol 1991; 7: 145-152. Abstract - Dentine hypersensitivity is a relatively common pain condition. Local pulpal inflammation, traumatic oral hygiene and dietary habits have been considered in the etiology of dentine hypersensitivity. Dentine hypersensitivity is probably caused by a change in fluid flow in the dentinal tubules, which in turn excites the nerve endings located at the pulp-dentine border. Consequently, treatment success would depend on the prevention of fluid flow across the dentinal tubules (sodium fluoride, stannous fluoride, sodium monofluorophosphate, strontium chloride, sodium citrate, potassium oxalate, and resins/adhesives), or on the desensitization of the nerve endings located at the pulp-dentine border (potassium nitrate). Although a wide variety of treatment methods have been available, clinical data is characterized wdth ambiguity, warranting

further research of the factors which could possibly be implicated in the occurrence of dentine hypersensitivity. Hypersensitive dentine is a pain condition in which an exposed dentine surface is sensitive to intraoral stimuli. Exposed dentine is a result of enamel loss or gingival retraction in combination with cementum loss. The pain-producing stimuli are thermal, mechanical and/or osmotic in nature, eliciting a range of sensations from mild discomfort to extreme pain to a stimulus that normally would be regarded as harmless (1). Usually the patient avoids the painproducing stimuli, and might refrain from toothbrushing or any other type of oral hygiene when this causes discomfort (2). Prevalence Few studies have been undertaken to determine the prevalence of hypersensitive dentine. In a Swiss dental practice, 14.5°o of the attending patients suffered from hypersensitive dentine (3). The prevalence of hypersensitive dentine in the West of Scotland was lower (89%), but could be due

to differences in the examination procedure (1) The examiners in Scotland considered the teeth to be hypersensitive when pain or discomfort was evoked by a cold stimulus as well as by scratching the dentine, while the Swiss examiners only measured a painful response after scratching. Bruno Collaert and CarIa Fischer^ Departments of ^Periodontology, ^Endodontics, University of Lund, Maimo, Sweden. Key words: dentine sensitivity; etiology; drug therapy; review. Bruno Collaert, Department of Periodontology, School of Dentistry, University of Lund, 214 21 Malmo, Sweden. Accepted for publication November 22, 1990. Pulp and dentine Dentine is continually formed throughout life by the odontoblasts, which have their processes at the pulpal third of the dentinal tubules (4). The tubules are fllled with a fluid resembling the composition of plasma (5). When the dentinal tubules are patent a constant outward flow of fluid is observed (6). Hypersensitive dentine usually loses its

hypersensitivity after a period of time. Natural desensitization can occur when irregular atubular dentine or irritation dentine is produced at the pulp-dentine border. The permeability of dentine is consequently reduced, due to the occlusion of tubules (7). Irritation dentine formation seems to be deficient in some individuals (8), explaining why some individuals remain hypersensitive for prolonged periods of time. Precipitation of mineral deposits in the dentinal tubules and coverage of the exposed dentine surface by calculus can also contribute to the desensitization (8). The dental pulp is richly innervated by extensively branching nerve fibers which form a dense network in the subodontoblast region, known as the plexus of Raschkow (9). Nerve fibers from the subodontoblastic nerve plexus were found penetreating the predentine, and extending in the tubules for 100 )J,m remaining in close contact with the odontoblast process (10). Juxtaposition of 145 Sou Sou Coliaert &

Fischer microradiographic study, obliteration of the dentinal tubules under sodium fluoride treated cavities was not detected (46). Biochemical blocking of neural transmission by the excess labile fluoride in the organic matrix of dentine has also been reported as an alternative or an additional explanation for the desensitizing action of fluoride (45). Recent studies have evaluated the desensitizing effect of iontophoretic application of fluoride. A reduction in sensitivity to mechanical and thermal stimuli using iontophoresis and 2% neutral sodium fluoride solution was reported, but improvement in the control teeth (solution without electric current) was also demonstrated after 7 days (47). Signiflcant relief from sensitivity was obtained in 90% of the patients with iontophoretic application of 2% sodium fluoride (48). Treating multiple-sensitive teeth by applying I^Q sodium fluoride iontophoretically in an alginate impression, was successful, but only documented in 2 patients (49).

The two previous studies have limited scientiflc value because they failed to include a control group and were not performed blindly, which makes data analysis inadequate. No significant difference between the application of sodium fluoride with or without iontophoresis in reducing patient response to a controlled cold stimulus was reported in a blind investigation of only 3 subjects in each group (50). Electrical current may enhance ion uptake by the dentinal tubules and aid in achieving desensitization by tubule occlusion (51). But before iontophoresis can be recommended as a routine procedure for treatment of dentine hypersensitivity, well controlled double-blind and long-term studies are needed to determine its effectiveness. Stannous fluoride Stannous fluoride has been incorporated in dentifrices and used in gel form. "Successful" results were obtained after the use of stannous fluoride gel (52,53). Stannous fluoride dentifrice was reported to be less effective than

monofluorophosphate, formalin and placebo dentifrices (37). During a 12week trial, stannous fluoride dentifrice applied with an ionizing brush was more effective than stannous fluoride with the same brush without current and as effective as strontium chloride toothpaste in providing relief to a cold stimulus (54). As with sodium fluoride, the formation of a calcifled barrier blocking tubule openings is the speculated mode of action (55). A scanning electron microscopy and electron microprobe study of dentine surfaces treated with stannous fluoride solution detected a layer containing tin and fluoride, which would provide mechanical and chemical protection for exposed dentine (56). In a similar report, deep 148 penetration of tin ions into dentine was demonstrated when the surface was pretreated by pumicing or etching, but not by brushing (57). This result was parallel with the clinical desensitizing effect of stannous fluoride in the same study. Brushing only of the surface was not

effective, which suggested either that brushing for this purpose is not advisable or that prolonged treatment may be necessary. Sodium monofiuorophosphate The clinical effectiveness of sodium monofluorophosphate dentifrices was reported in combination with 1.3% formalin (58), with strontium acetate (59) and wdth potassium nitrate (60). In a controlled study, a significant reduction was found in sensitivity to thermal stimulus with the combination dentifrice (sodium monofluorophosphate and 1.3%, formalin) as compared with the control (58) Similar improvements in dentine hypersensitivity were demonstrated after the use of dentifrices with and without sodium monofluorophosphate (59,60). When 0.76% sodium monofluorophosphate toothpaste was used as a control, no difference was found for thermal, chemical and mechanical stimuli when compared with a sodium citrate dentifrice (61). Monofluorophosphate is speculated to interact with hydroxyapatite, but such interaction has not yet been

demonstrated in dentine (36). In vitro, monofluorophosphate alone or in the presence of saliva produced no visual changes on the dentine and the tubules remained patent, as assessed by scanning electron microscopy (55). Markedly narrowing of dentinal tubules was shown in another scanning electron microscopic study (62), but this was attributed to the action of the other ingredients in the dentifrice. Strontium chioride Several reports in the 1960s and 1970s described reduction in dentine hypersensitivity when 10% strontium chloride was incorporated into a dentifrice. However, a strong placebo effect was always reported. After a 12-week treatment period, the placebo approached the same level of eflectiveness as the 10% strontium chloride dentifrice (63). The placebo effect has been attributed to the natural desensitizing process or to the abrasive component in the placebo paste (64). Another 12-week treatment study with strontium chloride found total relief from thermal and tactile

stimuli in 55% of the 29 subjects in the test group, while similar relief was found only in 14% of the 28 subjects in the placebo group (65). Treatment of dentine hypersensitivity with 10% strontium chloride dentifrice following Dentine iiypersensitivity periodontal surgery reduced the pain score to 75.5% in the test group after 7 days while the placebo reduced it to 34.2% (66) In comparative studies, strontium chloride was shown to be as effective as pluronic gel dentifrice with or without fluoride (40), less effective than 3 silica pastes (59), and less effective than potassium nitrate (67). Penetration of strontium ions into dentine was observed, suggesting that strontium ions may interfere with internal components of the dentine regardless of the desensitizing effect (57). Strontium chloride toothpaste had little effect on decreasing electrical resistence of the dentine in vitro, but granular formations in dentinal tubules were observed with scanning electron microscopy (62).

The desensitizing eflect of the strontium chloride dentifrice has been attributed to the abrasive filler of the toothpaste rather than to the proposed active ingredient (43,62,64). Sodium citrate The flrst study investigating dentifrices containing 2% dibasic sodium citrate/pluronic F-127 gel suggested that the polyglycol might decrease hypersensitivity by intratubular protein precipitation or aid precipitation of salivary mucins decreasing the tubule size (68). The combined activity of the ingredients appears to result in the production of the citrate anion derived from sodium citrate and citric acid. The citrate anion forms in conjunction with the calcium cation, which is found in dentinal tubules and on the dentine surface, a chemical complex (68). Thus, it may be that both sodium citrate and F-127 pluronic gel are active agents accomplishing dentinal tubular blocking. However, neither of these actions could be detected with scanning electron microscopy; a reduction of only 19^ {^

in the dentinal fluid flow was reported, which was believed to be caused by the filler of the paste which partially occluded the tubules (43). Eately, several investigations reported the eflectiveness of sodium citrate and pluronic gel (40,42,67,69), sodium citrate and silica abrasive (41) and sodium citrate with polaxamer 407 (61). Nevertheless, its clinical performance is still inconclusive. All these reports showed similar results, in which the eflectiveness of the dentifrice containing the citrate buffer system was not significantly different from other dentifrices or control groups. Potassium nitrate Potassium nitrate can be used as a desensitizing agent in the form of a solution, a gel, a paste or incorporated into dentifrices. Potassium nitrate den- tifrice was signiflcantly more effective than a placebo in reducing dentine hypersensitivity (60,67). Using electrical and cold stimuli in a double-blind study, relief in 92% of the 13 subjects using potassium nitrate was found in

contrast with only 2 1 % of the 14 subjects in the placebo group (67). When the effectivenes of a 5% potassium nitrate dentifrice was compared with 10% strontium chloride, 2% dibasic sodium citrate and 1.4% formalin dentifrices, the 5% potassium nitrate was the most effective agent iq reducing dentine hypersensitivity to electrical and cold stimuli (69). Another study failed to show superiority of a potassium nitrate dentifrice over a placebo in reducing dentine hypersensitivity (70). However, both tactile and air blast stimulus were uncontrolled and therefore not recommended for evaluation. Application of 10% potassium nitrate glycerin gel in acrylic trays was less effective than glycerin gel to a cold stimulus. This conflicting result could be due to the fact that potassium nitrate gel was not burnished onto the dentine, or that there was no abrasive in the gel to block the tubule appertures (71). Potassium nitrate proved unable to decrease fluid flow across dentine in vitro (43,64).

The desensitization effect of potassium nitrate is thought to be due to penetration of potassium ions into the pulp where the sensory nerves are prevented to repolarize after an initial depolarization, if increased levels of potassium are maintained. The depolarized state would decrease the pain perception (72). Oxalate In vitro investigations have shown promising results with potassium oxalate which was able to reduce the fluid flow across dentine with 98.4% (43) The reduction in dentine permeability for 2% potassium oxalate was recorded at 95.71 % (64) This desensitizing agent combines the tubule-occluding properties, with the inhibitory effect of potassium on nerve activity (23). If the hydrodynamic theory of dentine hypersensitivity is correct, one would expect that the oxalate-containing dentifrice would produce an immediate reduction in dentine sensitivity. Recent placebo controlled clinical studies evaluating the effectiveness of 30% dipotassium oxalate (73,74) and 3%

monohydrogen monopotassium oxalate (73,74), have reported signiflcant reductions in dentine sensitivity to controlled cold (73,74) and air (74) stimuli. Significant reductions in air and tactile sensitivity was also demonstrated with 6% ferric oxalate (75). In vitro and in vivo investigations have demonstrated promising results with oxalate salts. Further clinical trials, with larger sample size and longer 149 Collaert & Fisciier observation periods are necessary to support these findings. Resin and adhesives Resin has been reported to seal exposed dentinal tubules and to provide an immediate blockage of transmission of pain-producing stimuli to pulpal nerves (8). Promising results were demonstrated with composite resin in 20 patients with follow up periods of^ two to twelve months (8). After resin impregnation, no neural activity was recorded when the dentine of dog teeth was mechanically stimulated (76). The use of acid before resin-adhesive placement has been controversial.

It has been recommended to use an acid conditioner to open the tubules before impregnating them with a more resistent material (8). On the other hand it is not advocated to bring acid in contact with dentine. If the dentine bonding agent does not achieve the desired bond, the underlying dentine may be more permeable (due to the widening of tubule appertures by the acid conditioning) and thereby more sensitive than it would have been before (23). Glass-ionomer cements have also been recommended to seal dentinal tubules (77). The material is hydrophilic, has good mechanical strengh and is adhesive, which allows its placement without mechanical tooth preparation. Conclusion Although some questions in the pathogenesis of dentine hypersensitivity remain unanswered, all recent evidence supports the hydrodynamic theory. As for dentine hypersensitivity, experimental and epidemiologic data are too scarce to fully understand the cause of this condition. The cause in turn might influence the

natural desensitization proce.ss or interfere with treatment attempts Most patients with exposed dentine never experienced dentine hypersensitivity, others who were sensitive seemed to have undergone natural desensitization, while still others need treatment with no garantee of success. Traumatic toothbrushing, bacterial plaque and acidic dietary components are factors which might influence the occurrence of dentine hypersensitivity and need further exploration. The complexity of dentine hypersensitivity as outlined above may explain the contradictory results of the studies regarding treatment. Differences in study design, study duration, population size, subject selection and data analyses preclude comparisons between any two independent investigations (78). The methods used for treatment evaluation, even when standardized or controlled, can only 150 attempt to assess the subjective nature of pain (79). Often, the non-therapeutic components like abrasive fillers in dentifrices and

glycerin in gel forms were often considered the main promoters of dentine desensitization, instead of the so called active agent. This highlights the lack of knowledge about the exact mode of action of the desensitizing substances. The increase of longevity of the dentition may increase the incidence of dentine hypersensitivity due to more dentine surfaces at risk, therefore a simple and cost-effective approach would be the treatment of choice. Probably because of that, at home-use therapy has received most attention in the last decade. Among the available desensitizing agents, potassium nitrate and oxalate salts showed less ambiguous results. In case of severe and/or localized dentine hypersensitivity, it is advisable to combine a toothpaste with an in-office treatment of fluoride gels, paste or vanishes, and resins/adhesives. References 1. 2. 3. 4. 5. J, GALLOW.W R , OCHARDSON R The incidence of "hypersensitive" teeth in the West of Scotland. J Dent 1985; 13: 230-6.

EVERETT FG, HALL WB, PHATAK NM. Treatment of hypersensitive dentine J Oral Ther 1966; 2: 300-10 GRAF H , GALASSE R . Morbidity, prevalence and intraoral distribution of hypersensitive teeth. J Dent Res 1977; 56 (special issue): 162, A 479. THOMAS H F . The extend of the odontoblast process in human dentin. J Oral Pathol 1979; 58: 2207-18 GoFFEY GT, INGRAM MJ, BJORNDAL AM. Analysis of human FLYNN dentinal fluid. Oral Surg Oral Med Oral Pathol 1970; 30: 835 7. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. LINDEN LA, BRANNSTROM M . Fluid movements in dentin and pulp. An in vitro study of flow produced by chemical solutions on exposed dentin Odontol Revy 1967; 18: 227-36. BRANNSTROM M . Dentin and pulp in restorative dentistry Dental Therapeutics. Sweden: Nacka, 1981: 20 24 BRANNSTROM M , JOHNSON G, NORDENVALL KJ. Transmission and control of dentinal pain: resin impregnation for the desensitization of dentin. J Am Dent Assoc 1979; 99- 612-8 BERKOVITZ BKB, HOLLAND GR, NOXHAM BJ. A colour

atlas and textbook of oral anatomy. Smeets-Weert, Holland: Wolf Medical Publications Ltd.^ 1978: 105 GuNji T, KoBAYASHi S. Distribution and organization of odontoblast processes in human dentin. Arch Histol Jap 1983; 46: 213 8. FRANK RM. Ultrastructural relationship between the odontoblast, its process and the nerve fiber. In; Symons NBB, ed. Dentine and pulp Dundee: Thomson DG, 1968 LiLjA J. Innervation of the dentin Thesis 1980 University of Gotenborg, Sweden. BRANNSTROM M , ASTROM A. A study on the mechanism on pain elicited from the dentin. J Dent Res 1964; 43: 619 25 LiLjA J, NoRDENVAL KJ, BRANNSTROM M . Dentine sensitivity, odontoblasts and nerves under desiccated or infected experimental cavities. Swed Dent J 1982; 6: 93-103 BRANNSTROM M . The elicitation of pain in the human dentin and pulp by chemical stimulation. Arch Oral Biol 1962; 7: 59-62. BRANNSTROM M , JOHNSON G . Movements of the dentin and Dentine hypersensitivity pulp liquids on the application of thermal

stimuli. An in vitro study. Acta Odontol Scand 1970; 28: 59-70 17. ABSI E G , ADDY M , ADAMS D Dentine hypersensitivity A study of the patency of dentinal tubules in sensitive and nonsensitive cervical dentine. J Clin Periodontol 1987; 14: 280-4 18. YosHiYAMA M, MASADA J, UcHiDA A, IsHiDA H Scanning electron microscopic characterization of sensitive vs. insensitive human radicular dentin J Dent Res 1989; 68: 1498-1502. 19. YOSHIYAMA M , NOIRI Y, OZAKI K, UCHIDA A, ISHIKAWA Y, 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. IsHiDA H. Transmission electron microscopic characterization of hypersensitive human radicular dentin J Dent Res 1980; 69: 1293-7. PASHLEY DH. The dentin-predentin complex and its permeability; physiologic overview J Dent Res 1985; 64 (special issue): 613 20. DowELL P, ADDY M . Dentine hypersensitivity A review Aetiology, symptoms, and theories of pain production. J Clin Periodontol 1983; 10: 341-50. NARHI M V O . Dentin

sensitivity: a review J Biol Buccale 1985; 13: 75 96. PASHLEY DH. Dentin permeability, dentin sensitivity, and treatment through tubule occlusion. J Endodont 1986; 12: 465-74. OLGART L, BRANNSTROM M , JOHNSON G. Invasion of bacteria into dentinal tubules. Experiments in vivo and in vitro Acta Odontol Scand 1974; 32: 61-70. BERGENHOLTZ G, LINDHE J. Effect of soluable plaque factors on the inflammatory reactions in the dental pulp. Scan J Dent Res 1975; 83: 153-8. BERGENHOLTZ G . Effect of bacterial products on the inflammatory reactions in the dental pulp Scan J Dent Res 1977; 85: 122-9. WARFINGE J, DAHLEN G, BERGENHOLTZ G . Dental pulp response to bacterial cell wall material J Dent Res 1985; 64: 1046-50. NARHI M , HIRVONEN T. Functional changes in cat nerve activity after thermal and mechanical injury of the pulp. Proc Finn Dent Soc 1983; 79: 162-7. GRANT DA. Orbans pedodontics 4th ed St Louis: Mosby, 1963; 414-6. GHAZENS A I . The management of pain and sensitivity In: Ghazens AI

& Kaslick RS ed. Mechanism of pain and sensitivity of teeth and supporting tissues. Boston, Fairleigh Dickinson University School of dentistry and American Academy of Oral Medicine 1974; 12-13. ADDY M , MOSTAFA P, NEWCOMBE RG. Dentine hypersensitivity: The distribution of recession, sensitivity and plaque J Dent 1987; 15: 242 8. ADDY M , ABSI EG, ADAMS D. Dentine hypersensitiity The eflects in vitro of acids and dietary substances on rootplaned and burred dentine. J Clin Periodontol 1987; 14: 274-9 PASHLEY DH. Smear layer; physiological considerations Oper Dent 1984; 3: 13-29. BRANNSTROM M , JOHNSON G. Effects of various conditions and cleaning agents on prepared dentine surfaces; a scanning electron microscope investigation. J Prosthe Dent 1974; 31: 422-43 EMLING RG. Historical overview of causes and treatment of dentinal hypersensitivity. Compend Contin Educ Dent 1982; 3: 92-4. ADDY M , DOWELL P. Dentin hypersensitivity - A review Glinical and in vitro evaluation of treatment

agents. J Clin Periodontol 1983; 10: 351-6. MGFALL WT. A review of the active agents available for treatment of dentinal hypersensitivity. Endod Dent Traumatol 1986; 2: 141-9. GLARK DG, HANLEY JA, GEOGHEGAN S, VINET D. The effectiveness of a fluoride varnish and a desensitizing toothpaste in treating dentinal hypersensitivity. J Periodont Res 1985; 20: 212 6. 39.JAVID B, BARKHORDAR RA, BHINDA SV Gyanoacrylate A new treatment for hypersensitive dentin and cementum. J Am Dent Assoc 1987; 114: 486-8. 40.GoLLiNS JF, PERKINS L GHnical evaluation of the effectiveness of three dentifrices in relieving dentin sensitivity J Periodontol 1984; 55: 720-5. 41. GLARK DG, AL-JOBURI W, GHAN EG The efficacy of a new dentifrice in treating dentin sensitivity. Effects of sodium citrate and sodium fluoride as active ingredients. J Periodont Res 1987; 22: 89-93. 42. MCFALL WT, HAMRIGK SW Glinical effectiveness of a dentifrice containing fluoride and citrate buffer system for treatment of dentinal

sensitivity J Periodontol 1987; 58: 701 5 43. GREENHILL JD, PASHLEY DH The effects of desensitizing agents on the hydrauhc conductance of human dentin in vitro. J Dent Res 1981; 60: 686 98 44. PASHLEY DH, LEIBACH L G , HORNER JA The effects of burnishing NaF/Kaolin/glycerin paste on dentin permeability J Periodontol 1987; 58: 19-23. 45. TAL M , GEDALIA I, EHLICH J X-ray difraction and scanning electron microscope investigations of fluoride-treated dentin in man. Arch Oral Biol 1976; 21: 285-8 46. BRANNSTROM M , ISACSSON G , JOHNSON G The effect of calcium hydroxide and fluorides on human dentin Acta Odont Scand 1976; 34: 59-67. 47. LuTiNS W D, GREGO GW, MCFALL WT Effectiveness of sodium fluoride on tooth hypersensitivity with and without iontophoresis. J Periodontol 1984; 55: 285-8 48. GARLO GT, GiANCio SG, SEYREK S K An evaluation of iontophoretic application of fluoride for tooth desensitization J Am Dent Assoc 1985; 11: 761-5. 49. GANGAROSA LP Iontophoretic application of fluoride

by tray technique for desensitization of multiple teeth. J Am Dent Assoc 1981; 102: 50-2. 50. BROUGH K , ANDERSON O M , LOVE J, OVERMAN PR The effectiveness of iontophoresis in reducing dentin hypersensitivity. J Am Dent Assoc 1985; 111: 761-5 51. ZAKOK J, GEDALIA I, WEIMAN J, DAPHNI I Fluoride uptake by root dentin after immersion in 2*^/0 NaF solution with iontophoresis. J Dent Res 1976; 55: 310-4 52. TRASH WJ, DORMAN H L , SMITH F D A method to measure pain association with hypersensitive dentine. J Periodontol 1983; 54: 160-2. 53. BLONG M A , VOLDING B, TRASH WJ, JONES DL Effects of a gel containing 0.4 percent stannous fluoride on dentinal hypersensitivity. Dent Hyg 1985; 59: 489-92 54. JOHNSON R H , ZULGAR-NAIN BJ, KOVAL JJ The effectiveness of an electro-ionizing toothbrush in the control of dentinal hypersensitivity. J Periodontol 1982; 53: 353-9 55. BLUNDEN R , HOWE S, DOWELL P, ADDY M , ADMS D, MGGARTHY J . The effects of compounds used clinically in the management of dentin

hypersensitivity on some physical properties of dentin. J Dent Res IADR, British Division 1981; A 130. 56. ELLINGSEN JE, RoLLA G Treatment of dentin with stannous Ouoride-SEM and electron microprobe study. Scand J Dent Res 1987; 15: 281-6. 57.PENNEY DA, KARLSSON U L Fast desensitization of tooth roots by topically applied stannous fluoride and strontium chloride in dogs. Arch Oral Biol 1986; 21: 339-47 58. MCFALL WT, J R , MORGAN W G Effectiveness of a dentifrice containing formalin and monofluorophosphate. J Periodontol 1985; 56: 288-92. 59. ADDY M , MOSTAFA P Dentine hypersensitivity: A comparison of five toothpastes used during a 6-week treatment period. Br Dent J 1987; 163: 45-51 60. GouNGiL ON DENTAL THERAPEUTICS Acceptance of Promise with fluoride and Sensodyne toothpastes for sensitive teeth. 151 Collaert & Fischer J Am Dent Assoc 1986; 113: 673-5. ONG G , STRAHAN JD. Effect of a desensitizing dentifrice on dentinal hypersensitivity. Endod Dent Traumatol 1989; 5: 213

8. 62. ADDY M , MORGAN T The effect of toothpaste on the electrical resistence and scanning microscopic appearance of dentin J Dent Res 1982; 61: 547, A102 63. WEY S H Y , LAINSON PA, HENDERSON W, WOLFSON S H Evaluation of dentifrices for the relief of hypersensitive tooth surfaces Qiiint Int 1980; /• 67-73 61. 64. PASHLEY DH, OMEARA JA, KEPLER EE, GALLOWAY SE, THOMPSON SM, STEWART F R Dentin permeability. Effects 65. 66. 67. 68. of desen.sitizing dentifrices in vitro J Periodontol 1984; 55: 522-5. MiNKOFF S, AxELROD S. Efficacy of strontium chloride in dental hypersensitivity. J Periodontol 1987; 58: 470-4 UcHiDA A, WAKANO Y, FUKUY.M O , MIKI T, LA^WAYAMA Y, OK.D H Gontrolled clinical evaluation of 10°o strontium chloride dentifrice in treatment of dentin hypersensitivity following periodontal surgery J Periodontol 1980; 51: 578-81. TARBET WJ, SiLVERMAN G, JOSEPH MS, FRATARC.NGELO PA. Glinical evaluation of a new treatment for dentinal hypersensitivity. J Periodontol 1980;

51: 535-40 ZiNNER DD, DuANDY LF, LLTZ H J . A new desensitizing dentifrice. Preliminary report J Am Dent Assoc 1977; 95: 982-5. 69. TARBET WJ, SILVERMAN G , FRATARCANGELO PA, KANAPKA 152 JA. Home treatment for dentinal hypersensitivity: A comparative study J Am De?it Assoc 1982; 105: 227-30 70. MANOUCHERHR-POUR M , BHAT M , BISSADA N Glinical evaluation of potassium nitrate toothpastes for treatment of dentinal hypersensitivity. J Dent Res 1984; 63: 248, A696 71. REINHART TG, KILLOY WJ, LOVE J, OVERMAN PR, SAKUMU- RA JS. The effectiveness of a patient-applied tooth desensitizing gel A pilot study J Clin Periodontol 1990; 17: 123-7 72. KIM S Hypersensitive teeth: Desensitization of pulpal sensory nerves J Endodont 1986; 12: 482-5 73. MuzziN KB, JOHNSON R Effects of potassium oxalate on dentin hypersensitivity in vivo. J Periodontol 1989; 60: 151 8 74. DELANEY P, GOODMAN G, ROBINSON P, OSETEK E The effectiveness of topical potassium oxalate as a desensitizing agent J Dent Res

(Spec Issue) 1989; 68: Abstr 1860. 75. SALVATO A , TROULOS ES, GURRO FA, MERC:)LA MR, 76. 77. 78. 79. GING- OLD J. The effectiveness of ferric oxalate in relieving dentinal hypersensitivity. J Dent Res (Spec Issue) 1990; 69: Abstr 482 NARHI M , HIRVONEN TJ, HAKUMARI MO. The excitability of dog pulp nerves in relation to the condition of the dentine surf^ice. J Endodont 1984; 10: 294 8 WVcoFF SJ. Gurrent treatment for dentinal hypersensitivity Compend Cont Educ Dent 1982; Suppl. No 3, SI 13 -SI 15 MCGRATH P A . The management of human pain Endod Dent Traumatol 1986; 2: 124-9. GLARK GE, TROULOS ES. Designing hypersensitivity clinical studies. In: Gurro FA, Ed Tooth hypersensitivity The Dental Clinics of .North America, vol 34 (3); Philadelphia: Sanders Gompany, 1990; 531-44