Dentin Hypersensitivity

BMC Res Notes. 2014; 7: 31.
Published online Jan 13, 2014. doi:  10.1186/1756-0500-7-31

Effect of the clinical application of the diode laser (810 nm) in the treatment of dentine hypersensitivity

Nada Tawfig Hashim,corresponding author1 Bakri Gobara Gasmalla,2 Ahmed Hassan Sabahelkheir,3 and Alhadi Mohieldin Awooda4

1Khartoum North Dental Hospital, Faculty of Dentistry University of Sciences and Technology, Khartoum, Sudan
2Department of Oral Rehabilitation, Faculty of Dentistry, University of Khartoum, Khartoum, Sudan
3Laser Institute, Sudan University for Sciences and Technology, Khartoum, Sudan
4Department of restorative dentistry, University of Medical Sciences and Technology, Khartoum, Sudan
corresponding authorCorresponding author.
Nada Tawfig Hashim: moc.oohay@gifwatadan; Bakri Gobara Gasmalla: moc.oohay@01arabogirkab; Ahmed Hassan Sabahelkheir:moc.oohay@riehklehabasdemha; Alhadi Mohieldin Awooda: moc.oohay@idahla.rd

Received October 9, 2013; Accepted January 7, 2014.



Dentine hypersensitivity is prevalent amongst a large population of individuals with 30 to 40 years of age. Malnutrition due to dietary restrictions in some individuals causes oral discomfort and pain in some individuals. The nociceptive stimulus commonly reported in the majority of cases is that of cold, followed by the mechanical stimulus of tooth brushing and the chemical stimulus of diet with a high concentration of sugar [1].

Pain of dentine hypersensitivity is sharp, localized and of short duration. The hydrodynamic theory proposed by Brännströn Aström in 1964 [2] is the most acceptable theory in explaining the relationship between the pain of dentine hypersensitivity and the displacement of biological fluid in the dentinal tubules. Thermal, physical and chemical stimuli may cause the displacement of the pulp-dentine fluid, which trigger pulpal nervous terminations.

Under normal conditions, dentine is covered by enamel or cement and does not suffer direct stimulation. Only with the exposure of peripheral terminations of dentinal tubules a situation of strong dentinal sensitivity manifests itself as “hypersensitivity”. Occlusion of the exposed dentinal tubules can reduce the intensity of dentinal sensitivity. The most common clinical cause for exposed dentinal tubules is gingival recession. A wide range of mechanisms has been proposed as causes of recession such as abrasion due to faulty tooth brushing; abfraction; parafunctional habits or occlusal disequilibrium. Erosion has also been implicated in gingival recession, with its deleterious effect of acids in the oral cavity; as well as improperly controlled dentinal acid conditioning [1].

When gingival recession occurs, cementum is exposed. Cementum, is easily abraded or eroded away which exposing the underlying dentine [3].

Treatment of dentine hypersensitivity is challenging for both the patient and the healthcare provider and this can be due to the following reasons: It is difficult to measure/compare pain in different individuals and patients hardly change their habits that initially caused the problem. Hypersensitivity may be resolved without any treatment or may require several weeks of applying desensitizing agents before improvement is seen [4].

There are two principal treatments either to desensitize the nerve with potassium nitrate or to cover the dentinal tubules with composite restoration, glass ionemer cement, periodontal graft and crown placement [3].

With the advent of laser into the field of clinical dentistry a hope of overcoming some of the drawbacks of conventional dental procedures was raised. Since its first experiment for dental application in 1960s, the use of laser has been increased rapidly in the last couple of decades. Nowadays, wide varieties of procedures are carried out using lasers. Lasers are found to be effective in cavity preparation, caries removal, restoration removal, etching, and treatment of dentine sensitivity, caries prevention and bleaching [5] which are accomplished by the interaction of laser with the tissue, causing different tissue reactions, according to its active medium, wavelength and power density and to the optical properties of the target tissue [6].

Dentine Hypersensitivity is a challenging problem in dentistry with an increasing of its prevalence nowadays. Due to the availability of laser treatment and its ease of application this study was carried out among Sudanese patients with cervical dentine sensitivity for the first time.

The aim of this study is to assess the effect of diode laser (810 nm), with different exposure duration, in the treatment of dentin hypersensitivity.




A total of 14 teeth of 5 individuals (2 males and 3 females; aged 25 to 35 years old) with cervical dentine hypersensitivity were treated. Approval by the Ethics Committee and informed written consent was obtained at the clinic of Laser Institute, Sudan University of Science and Technology. The teeth included in the research were caries –free and showed no signs of active periodontal disease. The individuals with dentine hypersensitivity were recommended not to take any analgesics, anticonvulsants antihistaminic, sedative, tranquilizing or anti-inflammatory medications in the 72 hours preceding laser treatment, and not to use any desensitizer dentifrices in the last 6 weeks, and they should not been subjected to periodontal surgery in the last 6 months.

The tactile test was performed by the contact to the cervical dentine surface with a periodontal probe.

The samples were divided into 2 groups of 7 teeth: the 30 seconds exposure duration group and the 60 seconds exposure duration group.

The applied laser device was Diode Laser (810 nm) Oralia Company – Germany, with power of 20 Watt, class III (b).

This study was performed by one operator and one assessor responsible for the measurement of the pain level of the patients. The treatments were carried out in 2 sessions, a weekly interval.

The samples were evaluated by measuring the response of dentine hypersensitivity to the tactile stimulus. Scores were recorded in an analogous visual scale: score 10 (unbearable pain); 7 to 9 (strong and bearable pain), 4 to 6 (moderate pain), 1 to 3 (light pain) and 0 (no pain) [7]. The measurements were performed before each treatment session and at 15 min after laser application. This result was called immediate effect. Additional measurement was also performed at seven days after the laser application. This result was called late effect.

Except the exposure duration the irradiation parameters were identical, one of 30 seconds and other of 60 seconds (1 min). The power was one watt continuous emission form, and application with non contact mode on the region of exposed dentine.

Regarding the statistical analysis, all of the studied variables were described in relation to the mean and standard deviation. In order to compare the studied variables, Freidman test and Chi square test were applied; Two-Sample Kolmogorov-Smirnov Test was used for comparison of the two groups (30 seconds- 1 minute) after 15 minutes and after 1 week. The significance level of the test was .05.



Significant reduction of dentine sensitivity occurred along all times measured during the two treatment sessions in both groups treated with 30 seconds exposure duration and 60 seconds exposure duration. Comparing the responses in the 2 treatment sessions of the 2 groups, by using Kolmogorov- Smirnov test as shown in (Table 1) there was statistically significant difference ( p = .002) between the two groups after 15 minutes of laser application , z = 1.871. There is no difference between the two groups after one week, P = 1.000 (Figure 1).

Table 1


Comparison between the two groups (30 seconds- 1 minute) after 15 minutes and after 1 week

Figure 1


Comparison between the reading of pain before laser application, after 15 minutes from the application and after one week in both groups.

The results of treatments with the 30 seconds and 60 seconds exposure durations are reported in Tables 2 and ?and33and statistical results are reported in Tables 4 and ?and55.

Table 2


Group 1 with 30 seconds exposure duration

Table 3


Group 2 with 1 minute exposure duration

Table 4


Friedman test, group (1) 30 seconds

Table 5


Friedman Test, group (2) with 1 minute exposure duration



Although several types of treatments for dentine hypersensitivity have been demonstrated in the literature , there is no treatment that reduces pain to satisfactory levels.

Pain resulting from dentine hypersensitivity can be eliminated by interruption of stimuli transmission to the nerve endings of odontoblast processes which can be accomplished by reducing the fluid movement inside the dentinal canalicules, by narrowing or occlusion of tubules openings [8]. However, other treatment modalities have been proposed, such as laser therapy.

The use of He–Ne and GaAlAs lasers has shown a reduction in sensitivity to thermal and tactile stimuli [9,10]. Accordingly, in the present study, laser therapy promoted a considerable decrease in sensitivity, after 15 minutes and 7 days of the first application.

In this conducted research, it was observed that teeth, which presented exacerbated sharp pain during air blasting and tactile touch with dental instrument and continuous discomfort after the removal of these stimulation before desensitizing treatments were accomplished, showed an accentuated decrease of painful sensation immediately after 15 minutes of the first application of diode laser (810 nm) and even one week after initial irradiation. The rapid desensitizing effect of laser therapy observed in the conducted research may be attributed to a mechanism through which diode laser can induce changes in neural transmission networks within the pulp (depressed nerve transmission), rather than alterations in the exposed dentine surface, as observed with other treatment modalities [11]. In addition laser therapy may stimulate the normal physiological cellular functions. Therefore, the laser would stimulate the production of sclerotic dentine, thus promoting the internal obliteration of dentinal tubules [12] and this suggestion is reinforced by the histological analyses of dental pulps in teeth carried out by Matsumoto [13] the study showed a better degree of repair at 14 and 30 days after laser irradiation when compared with the non-irradiated dental pulp group.

The laser irradiation contributed to the repair of the dentine-pulp complex, preserving the pulpal vitality.



Based on the results obtained in the treatment of 14 teeth with cervical dentine hypersensitivity, by measuring the initial response between grade 8-9 in the quantitative numeric pain scale (maximum of the pain scale), we conclude that: 1) Diode laser (810 nm) provided a decrease in cervical dentine hypersensitivity.

2) The therapeutic immediate and late effects of the diode laser 810 nm with 60 seconds exposure duration were greater than those of the 810 nm with 30 seconds exposure duration.



GaAlAs: Gallium,. aluminum and arsenide; He-Ne laser: Helium and neon.


Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

NTH designed the study and carried out the data collection and the data analysis, AMA and AHS supervised the research, NTH writing/editing of the article with assistant of BGG. All authors have read and approved the final manuscript.



We are grateful to the staff of Laser Institute, Sudan University for Science and Technology. Special appreciation to all patients who allowed us to include them in this study. Also we are indebted to Azza Tajelsir and Elwalid Fadul for reviewing and editing the English language. We are great full to Mr Khalid Gobara for doing the statistical analysis of the study.


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Photomed Laser Surg. 2010 Oct;28 Suppl 2:S69-74. Epub 2010 Sep 23.

Effects of the combined desensitizing dentifrice and diode laser therapy in the treatment of desensitization of teeth with gingival recession.

Dilsiz A, Ayd?n T, Emrem G.

Department of Periodontology, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.


OBJECTIVES: The purpose of this study was to evaluate and compare clinically the efficacy of desensitizer toothpaste alone and in combination with the diode laser in the management of dentin hypersensitivity (DH), as well as both the immediate and late therapeutic effects on teeth with gingival recessions.

MATERIALS AND METHODS: In total, 52 teeth diagnosed with DH in 13 (seven women, six men, aged 16-48 years) healthy adult patients were included in this study, and teeth were randomly divided equally into two groups: the test group, which received treatment with desensitizer toothpaste and GaAlAs (diode) laser, and the control group, treated with desensitizer toothpaste. DH was assessed by means of an air stimulus, and a visual analogue scale (VAS) was used to measure DH. The selected teeth in the test group received laser therapy for three sessions. Teeth subjected to diode-laser treatment were irradiated at 100 mW for 25 sec at 808 nm, with continuous-emission, noncontact mode, perpendicular to the surface, with scanning movements on the region of exposed root surfaces.

RESULTS: Significant reduction of DH occurred at all times measured during the three treatment sessions in the test group. When compared with the means of the responses in the three treatment sessions of the two groups, the test group showed a higher degree of desensitization in teeth with gingival recession than did the control group (p < 0.001). The immediate and late therapeutic effects of the diode laser were more evident compared with those of desensitizer toothpaste.

CONCLUSIONS: Within the limitations of the present study, a significant effect of combined desensitizer toothpaste and diode laser therapy occurs in the treatment of desensitization of teeth with gingival recession. Desensitizer toothpaste appears to have the therapeutic potential to alleviate DH. Conversely, diode laser can be used to reduce DH.

Lasers Med Sci. 2010 Jun 30. [Epub ahead of print]

Low-level laser therapy of dentin hypersensitivity: a short-term clinical trial.


Orhan K, Aksoy U, Can-Karabulut DC, Kalender A.

Department of Oral Diagnosis and Radiology, Faculty of Dentistry, University of Ankara, Ankara, Turkey,



The aim of this study was to evaluate low-level laser therapy in cervical dentin hypersensitivity. A randomized controlled clinical trial was conducted with a total of 64 teeth. Dentin desensitizer and diode laser were applied on the cervical dentin surfaces. Distilled water and placebo laser was used as the placebo groups. The irradiance used was 4 J/cm(2) per treatment site. The baseline measurement of hypersensitivity was made by using visual analog scale (VAS). Twenty-four hours and 7 days after the application of desensitizer, diode laser and placebo groups, a new VAS analysis was conducted for the patients' sensitivity level. The mean pain scores of placebo groups were significantly higher than the desensitizer's and diode laser's mean scores (ANOVA, p < 0.05). The VAS analysis revealed a significant decrease in dentin hypersensitivity in 7 days with the use of the desensitizer and low-level laser therapy and no statistically significant difference was observed between these two treatments (p > 0.05). Although low-level laser and glutaraldehyde containing desensitizer present distinct modes of action, experimental agents caused a significant reduction of dentin hypersensitivity without showing secondary effects, not irritating the pulp or causing pain, not discoloring or staining the teeth, and not irritating the soft tissues at least for a period of 1 week with no drawbacks regarding handling and/or ease of application. Low-level laser therapy and desensitizer application had displayed similar effectiveness in reducing moderate dentin hypersensitivity.

Braz Oral Res. 2009 Jul-Sep;23(3):333-9.

Clinical evaluation of desensitizing treatments for cervical dentin hypersensitivity.

Aranha AC, Pimenta LA, Marchi GM.

Department of Restorative Dentistry, University of São Paulo, SP, Brazil.

The aim of this study was to compare different treatments for dentin hypersensitivity in a 6-month follow-up. One hundred and one teeth exhibiting non carious cervical lesions were selected. The assessment method used to quantify sensitivity was the cold air syringe, recorded by the visual analogue scale (VAS), prior to treatment (baseline), immediately after topical treatment, after 1 week, 1, 3 and 6 months. Teeth were randomly assigned to five groups (n = 20): G1: Gluma Desensitizer (GD); G2: Seal& (SP); G3: Oxa-gel (OG); G4: Fluoride (F); G5: Low intensity laser-LILT (660 nm/3.8 J/cm(2)/15 mW). Analysis was based on the non-parametric Kruskal-Wallis test that demonstrated statistical differences immediately after the treatment (p = 0.0165). To observe the individual effects of each treatment, data was submitted to Friedman test. It was observed that GD and SP showed immediate effect after application. Reduction in the pain level throughout the six-month follow-up was also observed. In contrast, LILT presented a gradual reduction of hypersensitivity. OG and F showed effects as of the first and third month respectively. It can be concluded that, after the 6-month clinical evaluation, all therapies showed lower VAS sensitivity values compared with baseline, independently of their different modes of action.

J Clin Periodontol. 2009 Aug;36(8):650-60. Epub 2009 Jun 10.

Immediate efficacy of diode laser application in the treatment of dentine hypersensitivity in periodontal maintenance patients: a randomized clinical trial.

Sicilia A, Cuesta-Frechoso S, Suárez A, Angulo J, Pordomingo A, De Juan P.

Clinica Sicilia, Oviedo, Spain.

BACKGROUND: To evaluate the immediate efficacy in the reduction of dentine hypersensitivity (DH) when applying an 810 nm diode laser (DL), and a 10% potassium nitrate bioadhesive gel (NK10%). MATERIAL AND METHODS: Forty-five consecutive periodontal maintenance patients of both sexes, with a DH >or= 2 on the verbal rating scale (VRS) in one or more teeth, were randomly allocated into three equal groups: 15 patients received DL and placebo gel; 15 patients were tested with a placebo laser and NK10%; and the remaining 15 received a placebo laser and placebo gel. The DH was evaluated at the start of the study, 15 and 30 min. after the laser application, and on days 2, 4, 7, 14, 30 and 60 by a blind examiner. RESULTS: After 15 min., observations showed a reduction in DH after an evaporative stimulus (ES) of 36.9% (0.86), three times greater than that of the control group (0.23) (p=0.008). After 14 days, this effect was even greater [DL 71.7% (1.67)/NK10% 36.3% (1.73)/control 28.1% (0.73); p=0.004], and lasted until day 60 [65.7% (1.53)/30.4% (0.73)/25.8% (0.67); p=0.01]. CONCLUSIONS: The DL and NK10% gel were proven effective in the treatment of DH. A significantly greater immediate response was observed with DL.

Int Dent J. 2009 Feb;59(1):35-46.

Laser applications in endodontics: an update review.

Mohammadi Z.

Department of Endodontics, Hamedan University of Medical Sciences, Hamedan, Iran.

The search for new devices and technologies for endodontic procedures always has been challenging. Since the development of the ruby laser by Maiman in 1960 and the application of the laser for endodontics by Weichman in 1971, a variety of potential applications for lasers in endodontics have been proposed. With the development of thinner, more flexible and durable laser fibres, laser applications in endodontics have increased. Since laser devices are still relatively costly, access to them is limited. The purpose of this paper is to summarise laser applications in endodontics, including their use in pulp diagnosis, dentinal hypersensitivity, pulp capping and pulpotomy, sterilisation of root canals, root canal shaping and obturation and apicectomy. The effects of lasers on root canal walls and periodontal tissues are also reviewed.

Arch Oral Biol. 2006 Jul;51(7):535-40. Epub 2006 Feb 3.

A comparison between the occluding effects of the Nd:YAG laser and the desensitising agent sensodyne on permeation through exposed dentinal tubules of endodontically treated teeth: an in vitro study.

Al-Azzawi LM, Dayem RN.

Department of Oral Pathology, College of Dentistry, University of Baghdad, Baghdad, Iraq.

OBJECTIVE: Dentine hypersensitivity may occur due to loss of covering enamel and/or loss of cementum after gingival recession, resulting in exposure of cervical dentine and patency of dentinal tubules. The effect of thermally cooled pulsed neodymium:yttrium-aluminium-garnet (Nd:YAG) laser on the permeability and structural appearance of the root canal wall was investigated in vitro. The aim of this study was to compare the occluding effect of Nd:YAG laser with that of sensodyne on exposed dentine. MATERIAL AND METHODS: Forty freshly extracted human maxillary anterior teeth were collected at random. Root canal obturations were performed using master apical file no. 60 k-type for obturated teeth. All teeth were stored in 100% humidity at 37 degrees C for 48h to allow time for the sealer to set. Dentine of 35 teeth was exposed by removing the cementum, and the remaining five teeth represented a negative control group. Specimens were examined using stereomicroscopy to show the surface topography of the dentine substrate before and after treatment with Nd:YAG laser or sensodyne. RESULTS: A double-blind technique was used when taking measurements of ink penetration (in mm) for each group. Teeth treated by Nd:YAG laser showed the least ink penetration, followed by teeth treated by sensodyne. The positive control group demonstrated complete ink penetration and the negative control group showed no ink penetration. Stereomicroscopic examination of specimens treated with Nd:YAG laser showed deposition on the dentinal surface, and specimens treated with sensodyne showed partial deposition. Untreated specimens were free of deposition and the tubules remained patent. CONCLUSION: There is no significant difference in the occluding effect of Nd:YAG laser and sensodyne toothpaste. Both treatments have a promising effect on the reduction of permeation through exposed dentinal tubules. However, the occluding effect of Nd:YAG laser occurs within seconds whereas that of sensodyne takes at least 3 weeks.

Rev Belge Med Dent. 2005;60(2):115-45.

[LASER applications in endodontics]

[Article in French]

De Moor R, Roeykens H, Meire M, Depraet F.

Université de Gand, Département de Médecine Dentaire & Clinique de Médecine Dentaire, Stomatologie et Chirurgie maxillo-faciale, Service de Dentisterie Opératoire et d'Endodontie, UZ Gent – De Pintelaan 185 (P8), B-9000 Gand.

Since the development of the ruby laser by Maiman in 1960 and the application of the laser for endodontics by Weichman in 1971, a variety of lasers with a wide range of characteristics are now being used in endodontic therapy. In the past two decades much experience and knowledge has been gained The first purpose of the present paper is to provide an understanding of the essential physical science behind laser technology and information on the effects of laser beams on tissue (tissue interaction). A second purpose is to summarize laser applications in endodontics, including their use in pulp diagnosis, dentinal hypersensitivity, pulp capping and pulpotomy, modification of the root canal walls, sterilization of the root canal system, cleaning–shaping–obturation of the root canal, and endodontic surgery. It will be clear that a number of endodontic procedures with conventional treatments cannot provide comparable results or are less effective.

Braz Dent J. 2004;15(2):144-50. Epub 2005 Mar 11.

Laser therapy in the treatment of dentine hypersensitivity.

Ladalardo TC, Pinheiro A, Campos RA, Brugnera Júnior A, Zanin F, Albernaz PL, Weckx LL.

Federal University of São Paulo, UNIFESP-EPM, São Paulo, SP, Brazil.

Cervical dentine hypersensitivity is the most frequent complaint among reported odontalgias. Thus, this study evaluated the effectiveness of two types of lasers (660 nm wavelength red, and 830 nm wavelength infrared) as dentine desensitizers, as well as both the immediate and late therapeutic effects in individuals 25 to 45 years of age. A total of 40 teeth with cervical exposure were treated in 4 sessions. They were divided into 2 groups according to treatment. A 660 nm wavelength red diode laser and an 830 nm wavelength infrared diode laser were used. Dentine sensitivity to cold nociceptive stimulus was evaluated by means of a pain numeric scale from zero to 10 before each treatment session, at 15 and 30 min after irradiation, and in a follow-up period of 15, 30 and 60 days after the end of treatment. Significant levels of dentinal desensitization were only found in patients ranging in age from 25 to 35 years. The 660 nm red diode laser was more effective than the 830 nm infrared laser and a higher level of desensitization was observed at the 15 and 30 minute post-irradiation examinations. The immediate and late therapeutic effects of the 660 nm red diode laser were more evident in 25-35-year-old patients compared with those of the 830 nm infrared diode laser, in terms of the different age groups.

J Clin Laser Med Surg. 2003 Oct;21(5):291-6.

Effect of the clinical application of the GaAlAs laser in the treatment of dentine hypersensitivity.

Marsilio AL, Rodrigues JR, Borges AB.

Restorative Dentistry, UNESP School of Dentistry, São José dos Campos, SP, Brazil.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of the clinical use of the gallium-aluminum-arsenium (GaAlAs) laser at the maximum and minimum energies recommended by the manufacturer for the treatment of dentine hypersensitivity. BACKGROUND DATA: Dentine hypersensitivity (DH) is a response to a stimulus that would not usually cause pain in a healthy tooth. It is characterized by sharp pain of short duration from the denuded dentin. Its etiology is unknown. The dentin only begins to show sensitivity when exposed to the buccal environment. This exposure can result after removal of the enamel and/or dental cement, or after root denudation. Different treatments are proposed for this disorder. MATERIALS AND METHODS: In this study, 25 patients, with a total number of 106 cases of DH, were treated with GaAlAs low-level laser therapy (LLLT). 65% of the teeth were premolars; 14% were incisors and molars; 6.6% were canines. The teeth were irradiated with 3 and 5 J/cm2 for up to six sessions, with an interval of 72 h between each application, and they were evaluated initially, after each application, and at 15 and 60 days follow-up post-treatment. RESULTS: The treatment was effective in 86.53% and 88.88% of the irradiated teeth, respectively, with the minimum and maximum energy recommended by the manufacturer. There was a statistically significant difference between DH and after a follow-up of 60 days for both groups. The difference among the energy maximum and minimum was not significant. CONCLUSION: The GaAlAs low-level laser was effective in reducing initial DH. A significant difference was found between initial values of hypersensitivity and after 60 days follow-up post-treatment. No significant difference was found between minimum (3 J/cm2) and maximum (5 J/cm2) applied energy.

J Oral Rehabil. 2003 Dec;30(12):1183-9.

Clinical evaluation of low-level laser therapy and fluoride varnish for treating cervical dentinal hypersensitivity.

Corona SA, Nascimento TN, Catirse AB, Lizarelli RF, Dinelli W, Palma-Dibb RG.

Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto, Brazil.

The aim of this study was to evaluate in vivo the use of low-level galium-aluminium-arsenide (GaAlAs) (BDP 600) laser and sodium fluoride varnish (Duraphat) in the treatment of cervical dentine hypersensitivity. Twelve patients, with at least two sensitive teeth were selected. A total of 60 teeth were included in the trial. Prior to desensitizing treatment, dentine hypersensitivity was assessed by a thermal stimulus and patients' response to the examination was considered to be a control. The GaAlAs laser (15 mW, 4 J/cm2) was irradiated on contact mode and fluoride varnish was applied at cervical region. The efficiency of the treatments was assessed at three examination periods: immediately after first application, 15 and 30 days after the first application. The degree of sensitivity was determined following predefined criteria. Data were submitted to analysis and no statistically significant difference was observed between fluoride varnish and laser. Considering the treatments separately, there was no significant difference for the fluoride varnish at the three examination periods, and for laser therapy, significant difference (P < 0.05) was found solely between the values obtained before the treatment and 30 days after the first application. It may be concluded that both treatments may be effective in decreasing cervical dentinal hypersensitivity. Moreover, the low-level GaAlAs laser showed improved results for treating teeth with higher degree of sensitivity.

Aust Dent J. 1994 Dec;39(6):353-7.

Low level laser therapy for dentinal tooth hypersensitivity.

Gerschman JA, Ruben J, Gebart-Eaglemont J.

Oro-Facial Pain Clinic, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne.

A comparative double blind study testing low level laser therapy (Gallium/Aluminium/Arsenide laser [GaAlAs]) against placebo was carried out in the management of dentinal tooth hypersensitivity. Subjects demonstrating dentinal hypersensitivity and complying with strict selection criteria were randomly assigned to an active and placebo group. Low level laser therapy was applied for one minute to both the apex and cervical area of the tooth; and reapplied at one week, two-week and eight-week intervals. Dentinal hypersensitivity was rated at each visit. There were 28 subjects in the placebo group and 22 and 21 subjects, respectively, in the tactile sensitivity and thermal sensitivity groups. Comparisons between the groups were conducted using independent groups t-test. In both the tactile and thermal sensitivity groups differences between the active and placebo groups were significant from the first week and increased further in the second and eighth weeks. The mean value of thermal sensitivity decreased 67 per cent (p < 0.001) compared with placebo (17 per cent) and tactile sensitivity decreased 65 per cent (p = .002) compared with placebo (21 per cent) at eight weeks. Results demonstrate that the GaAlAs laser is an effective method for the treatment of both thermal and tactile dentinal hypersensitivity. There were no reported adverse reactions or instances of oral irritation.