Effects of different treatments on chemical and

Lasers in Medical Science https://doi.org/10.1007/s10103-018-2482-0

ORIGINAL ARTICLE

Effects of different treatments on chemical and morphological features of eroded dentin Sandra Kiss Moura 1,2 & Carolina Cury Lopes 1 & Livia Tosi Trevelin 3 & Adriana Bona Matos 3 & Íssis Virgínia Luque Martinez 4 & Marcelo Estevam 5 & Sandra Kalil Bussadori 2 Received: 23 November 2017 / Accepted: 9 March 2018 # Springer-Verlag London Ltd., part of Springer Nature 2018

Abstract To evaluate the treatment of eroded dentin (Sensodyne Repair & Protect™, Er:YAG laser and combinations). The occlusal surfaces of 25 third molars were sectioned 1.5 mm in thickness. After an erosion cycle (5 min in demineralizing solution + 3 h in remineralizing solution; six cycles a day for 8 days), the samples were divided into five groups (n = 5): (E) erosion − control; (ES) erosion + Sensodyne Repair & Protect (NovaMin); (EL) erosion + Er:YAG laser (40 mJ, 10 Hz, 0.4 W, 50 μs, 3.1 J/cm2, 63 W/ cm2); (ELS) erosion + Er:YAG laser + Sensodyne; and (ESL) erosion + Sensodyne + Er:YAG laser. Following storage in ultrapure water (37 °C/14 days), the Ca/P ratio was evaluated by EDXRF and the morphology surfaces examined in SEM. The percentage of exposed dentin tubules was calculated. One-way analysis of variance and Tukey’s test at 5% were used to treat the data. The Ca/P ratio was higher in E and ES groups. More exposed dentin tubules were found in E group and less exposed tubules were found in the ES group (p < 0.0001). When the toothpaste and laser were combined, the number of occluded dentin tubules was higher when laser was performed first (ELS). A positive effect was found when the laser and toothpaste were combined. Keywords Dental erosion . Laser . Desensitizing agents

Introduction Dental erosion is the progressive, irreversible loss of hard dental tissue (enamel and dentin) stemming from the chemical action of acids, with no bacterial involvement [1]. Intrinsic factors associated with the etiology of dental erosion include

* Sandra Kiss Moura [email protected] 1

Department of Dentistry, University North of Parana (UNOPAR), Rua Marselha 183, Londrina 86010141, Brazil

2

Department of Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), Rua Vergueiro 245, São Paulo 01504000, Brazil

3

Department of Dentistry, University of São Paulo (FOUSP), Av Prof Lineu Prestes 2227, São Paulo 05508000, Brazil

4

Dentistry Academic Unit, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

5

LPIS Health Research and Innovation Laboratory, Federal Institute of Parana (IFPR), Av João XXIII 600, Londrina 86060370, Brazil

gastroesophageal acid reflux and eating disorders, which often affect the teeth and can lead to severe enamel and dentin loss [2]. The treatment of dental erosion is complex due to the constant acid challenge and dentinal sensitivity is a common complaint [3]. Tooth sensitivity is one of the indications for the use of laser. Surgical laser occludes dentinal tubules, whereas nonsurgical laser therapy has analgesic, anti-inflammatory, and biostimulating effects on the dental pulp, leading to the formation of reactionary dentin [4]. The effect of laser on the reduction in tooth sensitivity has been described for 810-nm diode laser [5], in vivo Er:YAG laser [6] and Nd:YAG laser with a desensitizing agent six months after administration [3]. The occlusion of dentinal tubules has been demonstrated after the administration of Er:YAG laser and an arginine-based toothpaste, with better results achieved when laser was combined with the desensitizing agent [7] and sealing of the dentinal tubules after the administration of Nd:YAG laser, with no harm to the pulp [8]. Another desirable effect of laser on eroded dental tissue is the increase in mineral content and the consequent increase in resistance to demineralization due to the constant acid

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challenge. One study demonstrated that the mineral content of dentin irradiated with Er:YAG, Nd:YAG and KTP laser was similar in terms of Ca, K, Mg, Na, P, and the Ca/P ratio [9]. Despite the effective reduction in dentin sensitivity, CO2 and Er:YAG did not alter the mineral content of dentin [10]. The combined effects of Er:YAG laser and a toothpaste containing nano-carbonate apatite (n-CAP) were analyzed [11] on the occlusion of dentinal tubules, but did not evaluate the longterm effect. Indeed, few studies have addressed changes in the composition of eroded dental tissues submitted to the laser therapy and the combination of laser with desensitizing or remineralizing agents. The NovaMin® technology found in Sensodyne Repair & Protect® was developed for the treatment of tooth sensitivity, the prevention of dental demineralization and the promotion of remineralization. NovaMin® is a bioactive glass originally developed as a material for bone regeneration [12] that reacts with water and saliva to release mineral ions for remineralization, depositing hydroxycarbonate apatite and occluding dentinal tubules [13]. NovaMin® combined with laser therapy has been found to reduce cervical dentinal sensitivity [14]. Despite the apparently promising results, it is necessary to determine the effects of this treatment under conditions of prolonged acid challenge, as in the case of dental erosion. The aim of the present study was to evaluate the effect of different treatments for dental erosion (Sensodyne Repair & Protect® with NovaMin®, Er:YAG laser and combinations of the two treatments) on the chemical composition (Ca/P ratio) and morphology of eroded dentin.

Materials and methods Experimental design A randomized study design was employed with one experimental factor (dentin treatment) on five levels (n = 5): erosion (E) (control, without treatment); erosion + Sensodyne Repair and Protect® (NovaMin®, Sensodyne®, Middlesex, UK) (ES); erosion + Er:YAG laser irradiation (Fidelis Er III 1000, Fidelis, Fotona, Slovenia) at 40 mJ, 10 Hz, 0.4 W, 50 microseconds, 3.1 J/cm2, 63 W/cm2 (EL); erosion + Er:YAG laser irradiation + Sensodyne (ELS); erosion + Sensodyne + Er:YAG laser irradiation (ESL) [15]. The experimental units were eroded dentin discs. The Ca/P ratio evaluated using Xray dispersive spectroscopy and the percentage of exposed dentin tubules were the response variables. All procedures involving human participants were conducted in accordance with the ethical standards of the national ethics committee as well as the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Preparation of specimens Following approval from the human research ethics committee (certificate number: 1.209.605), 25 sound third molars were disinfected in a 0.5% chloramine solution (Vetec Química Fina Ltda., RJ, Brazil) and stored in ultrapure water (Elga, Purelab Option-Q DV25, São Paulo, Brazil) at 4 °C. The occlusal surfaces were removed with a diamond disk (Extec 12205, Erios, São Paulo, SP, Brazil) and a precision sectioning saw (ISOMET 1000, Buhler Ltd., Lake Bluff, IL, USA) at 200 rpm in the mesio-distal direction and a second cut was performed parallel to the first to obtain dentin disks measuring 1.5 mm in thickness. After storage in ultrapure water for 72 h, the erosion cycle, adapted from Zimmerli [16], was simulated with immersion in demineralizing solution (1% citric acid solution, pH 3.5) and remineralizing solution (0.002 g of ascorbic acid, 0.58 g of NaCl, 0.17 g of CaCl2, 0.16 g of NH4Cl, 1.27 g of KCl, 0.16 g of NaSCN, 0.33 g of KH2PO4 and 0.34 g of Na2HPO4 dissolved in ultrapure water, pH 6.4). Each cycle consisted of immersion in the demineralizing solution for 5 min, followed by rinsing with ultrapure water for 1 min and immersion in the remineralizing solution for 3 h. Each specimen was submitted to six daily erosion cycles for eight consecutive days. During the erosion process, the disks were stored at 37 °C, and after this step, the specimens were stored in ultrapure water at 37 °C for 7 days prior to receiving the treatments. The treatments were conducted as follows: ES group—active scrubbing with the toothpaste (¼ of a 5-ml syringe) with a microbrush for 2 min, followed by immersion in ultrapure water; EL group—application of Er:YAG laser (40 mJ, 10 Hz for 50 μs in pulsed mode) and immersion in ultrapure water; ELS group—toothpaste applied after laser using the same method described above; and ESL—toothpaste applied before laser. At the end of the treatments, all specimens were stored in ultrapure water for 14 days. The irradiation protocol used was Er:YAG laser (Fidelis Er III 1000 model, Fidelis, Fotona, Slovenia) at 40 mJ, 10 Hz, 0.4 W, 50 μs wide pulse. During irradiation, a high accuracy translation platform (ESP301, Newport Corporation, Invine, CA, USA) was used. The dentin sample was attached to the platform base (incidence 90°) maintaining a focused mode distance (7 mm), which moved automatically (0.8 mm/s) according to commands previously established through software connected to the scanning device, enabling the irradiation to reach the entire dentin area. The laser energy was delivered by a R02 hand piece, with a spot size of 0.9 mm in diameter under continuous spray (4 A/6 W = 21 ml/min). The following were the parameters for the laser equipment: Area (A): 6.3 × 10−3 cm2; irradiance (I): 63 W/cm2; energy density (ED): 3.1 × 10−3 J/cm2. The equipment operated in wide pulsed mode with cooling.

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The chemical composition of all specimens was analyzed using energy-dispersive X-ray fluorescence spectroscopy (EDXRF) and the morphology of the surfaces was examined using scanning electron microscopy, followed by the calculation of the percentage of area of exposed dentinal tubules. In this step, five additional dentin disks were used to investigate the isolated effects of the presence of the smear layer produced by abrasion with 600 grit silicon carbide (SiC) sandpaper for 60 s with cooling in comparison to the treatments.

the UTHSCSA ImageTool 3.0 for Windows (Department of Dental Diagnostic Science at the University of Texas Health Science Center, San Antonio, Texas, USA) by an examiner who was blinded to the allocation of the different specimens. For the statistical analysis, the mean percentages of areas of exposed dentinal tubules calculated for the dentin disks in each group were considered. The Shapiro-Wilk normality test was used to determine the distribution of the data. One-way analysis of variance and Tukey’s test were used for the comparisons, with the level of significance set to 5% (p < 0.05).

Analysis of chemical composition The chemical composition was evaluated using EDXRF spectroscopy (EDX-7000, Shimadzu®, Kyoto, Japan). The percentages of calcium (Ca) and phosphorus (P) were calculated and expressed as the Ca/P ratio in each condition. For such, a collimator was used to select a circular area measuring 3 mm in diameter to measure the chemical composition of the dentin. The excitations and detections of the characteristic X-rays of the chemical elements in the sample were performed in atmospheric air, using electrical tension of 50 kVand a current of 17 μA for the quantification of elements in the aluminum to uranium band and electrical tension of 15 kV and a current of 310 μA for elements from sodium to scandium. Each reading lasted 200 s and was performed in triplicate for each dentin disk. The equipment was calibrated to quantify only Ca and P, which account for more than 90% of the mineral portion of dentin, with a 95% confidence interval. The data of the mapped area of each specimen were digitized using the PCEDX/PCEDX-Navi ver. 2.01 software (Shimadzu®, Shimadzu Corp., Kyoto, Japan), which provided mean Ca and P values (%).For the statistical analysis, the mean of three readings of each specimen was used to calculate the percentages of Ca and P, expressed by the Ca/P ratio for each condition. The Shapiro-Wilk normality test was used to determine the distribution of the data. One-way analysis of variance and Tukey’s test were used for the comparisons, with the level of significance set to 5% (p < 0.05).

Analysis of dentin morphology and calculation of the area of exposed dentinal tubules The morphology of the dentin was examined using scanning electron microscopy (Hitachi Co, Tokyo, Japan) operating at 15 Kv. After the EDXRF analysis, the specimens were submitted to critical point drying, covered with gold and examined. Three photomicrographs were obtained for each treatment (magnification × 1000). The dentin surfaces after the smear layer (abrasion with 600 sandpaper for 60 s under cooling) and erosion cycle were also compared to the treatments. The relative percentage of the area of exposed dentinal tubules was calculated on three photomicrographs from each experimental condition. The readings were performed using

Results Chemical composition analysis (EDXRF) Table 1 displays the mean and standard deviation values of the Ca/P ratio in the different experimental groups. Statistically significant differences were found among the groups (p < 0.0001). The highest Ca/P ratio was found in the E group, followed by the ES group. Similar findings were observed for EL and ESL. The lowest Ca/P ratio was found in the ELS group.

Analysis of dentin morphology and percentage of area of dentinal tubules Three photomicrographs were obtained for each experimental condition to illustrate the effect of the treatments after the erosion cycle and calculate the percentage of the area of exposed dentinal tubules (Fig. 1). The morphology of the dentin varied among the groups (Fig. 1). Exposed dentinal tubules were found in the E group, but not in the ES or smear layer groups. Laser irradiation of the dentin following erosion led to less exposure of dentinal tubules. Laser followed by Sendosyne Repair and Protect led to less exposure than Sensodyne followed by laser. Table 2 displays the mean and standard deviation values for the percentage of exposed dentinal tubules in each group. The largest area of exposed dentinal tubules was found in the E group and the smallest was found in the ES and smear layer groups (p < 0.0001). These results are in agreement with the photomicrography analysis. Comparing the two groups with combined treatments, a smaller area of exposed dentinal tubules was found when laser was performed prior to the application of the toothpaste, which confirms the photomicrography findings.

Discussion In the present study, dentin erosion was simulated with cycles of demineralization and remineralization in an attempt to

Lasers Med Sci Table 1 Ca/P ratios in different experimental group (n = 5). The power test calculated was 1 (∞ = 0.05) Group

Mean (standard deviation)

Erosion (E)

27.53 (1.79) A

Erosion + Sensodyne Repair & Protect® (ES)

12.69 (1.03) B

Erosion + Er:YAG laser (EL) Erosion + Sensodyne + Laser (ESL)

9.29 (0.97) C 9.97 (1.57) C

Erosion + Laser + Sensodyne (ELS)

7.52 (0.13) D

reproduce what occurs in the oral cavity in cases of acid reflux. The protocol used [16] opened the dentin tubules whereas the SiC paper produced smear layer and occluded dentin tubules. These findings were confirmed by the photomicrographs at Fig. 1. As expected the Ca/P ratio was highest in the erosion group because the erosion cycle exposed the dentin in a compatible manner to prolonged exposure of the teeth to an acid challenge, as occurs in non-carious lesions (erosion, abrasion, abfraction and friction). Hypersensitivity of the dentin is a common complaint among adults as a consequence of erosion [3]. The treatment of tooth sensitivity stemming from erosion is possible using laser irradiation [17]. In the present study, the Er:YAG laser was employed and the ablation of dentin occurred [18]. Previous study [19] noticed a minimal thermal effect when frequency of Er:YAG laser was of 2 and 5 Hz

using an energy dose of 74 to 80 J/cm2, but the authors failed to mention the calculation of the irradiance or in which mode the laser was operated and they did not say if the laser was delivered in contact with the tissue or not. In the present study, the output energy dose was much lower (3.1 J/cm2) and it was delivered 7 mm in distance from the dentin surface, which means that the energy was attenuated. These parameters produced the ablative effect of Er:YAG laser without the carbonization of the dentin. However, the risk of thermal damage when using the Er:YAG laser should be taken into consideration. This finding confirms that the effect of laser depends on the parameters established for each application purpose as well as knowledge on the characteristics of the tissue to receive the irradiation. In clinical terms, the ablation of the dentinal surface by the Er:YAG laser exposed the deep dentin, which did not have contact with acids. Deep dentin has more tubules per mm2, since they converge toward the pulp, and therefore has a greater amount of peri-tubular dentin, unlike surface dentin, which has fewer tubules per mm2 and more inter-tubular dentin. Thus, ablation exposes more mineralized dentin with tubules of a smaller diameter. During an acid erosion challenge, dental wear could be aggravated if the Er:YAG were the only treatment due to the ablative effect. Therefore, toothpaste containing Novamin was combined with the laser procedure to offer a barrier to the progression of erosive wear. The aim of applying Novamin after the laser was to promote a chemical reaction

Fig. 1 Photomicrographs of treatments (magnification × 1000; Bar = 10 μm). Arrows and symbols point to exposed dentinal tubules in different experimental conditions (Erosion, Erosion + Laser, Erosion + Laser + Sensodyne, Erosion + Sensodyne + laser, Smear-Layer)

Lasers Med Sci Table 2 Percentage area (%) of exposed dentinal tubules in different groups (n = 5). Different letters denote statistically significant differences. The power test calculated was 0.96 (∞ = 0.05) Group

Mean (standard deviation)

Erosion

11.55 (1.38) A

Smear Layer Erosion + Sensodyne Repair & Protect® (ES)

0 (0) B 0.13 (0.10) B

Erosion + Er:YAG laser (EL) Erosion + Sensodyne + Laser (ESL)

5.05 (1.00) C 5.02 (0.95) C

Erosion + Laser + Sensodyne (ELS)

3.30 (0.75) D

with the hydroxyapatite to obliterate the tubules and impede the advance of the erosion. Irradiation of dentin with laser is influenced by dosimetric parameters, condition of the irradiated surfaces and type of laser [20]. The absorption of laser wavelengths is influenced by the presence of water molecules, proteins, and pigments [20]; in this study, water absorbed the wavelength of Er:YAG producing ablation. In case of eroded dentin, different effects from what is known for sound dentin might be expected if one considers the continuous acid challenge. A recent study [21] showed that the parameters established for Nd:YAG laser (considered the gold standard for the treatment of hypersensitivity) on sound dentin could not be used on eroded dentin. But differences might be considered since the Nd:YAG laser wavelength is preferably absorbed by pigments which is not the case of Er:YAG laser. Our findings confirm the results of a previous study [22] that Er:YAG produced morphological changes similar to those found after acid etching, without fracturing, fusing or carbonizing the dentin. Researchers [23] described the effects of microscopic occlusion in dentinal tubules with the administration of Er:YAG laser. More prominent occlusion of dentinal tubules has been observed after irradiation with Er:YAG laser followed by the application of a toothpaste containing arginine [12, 24]. In the present study, a single application of Sensodyne Repair and Protect covered the surface of the eroded dentin and did not enable the visualization of open dentinal tubules (Fig. 1), which could lead to the mistaken interpretation that this is the best treatment option in cases of erosion. Thus, the interpretation of the photomicrographs should be performed with caution, as exposure of the dental surface to acids from diet or gastoesophageal reflux occurs successively, removing and modifying the treated surfaces (Fig. 1). Moreover, one can see in the same figure that the administration of laser alone (EL group) or after Sensodyne (ESL group) resulted in similar values for the areas of exposed dentinal tubules. However, when inverting the treatment sequence (ELS group), a lower area of exposed dentinal tubules was found in comparison to the ESL and EL groups. This finding suggests that laser should be used

to initiate treatment and the toothpaste should be applied subsequently to obtain a greater obliteration effect on eroded dentin (measured here by the percentage of remaining opened dentinal tubules. This combination for the treatment of dental erosion may be capable of resisting subsequent cycles of erosion, which justifies the continuity of this research to verify this aspect. The mode of action of Sensodyne Repair and Protect is based on the NovaMin® technology, that was originally developed as a material for bone regeneration [12] because it contains bioglass that reacts with water and saliva to release mineral ions for remineralization, depositing hydroxycarbonate apatite and occluding dentinal tubules [13]. It explained the reduction of dentin sensitivity when it was used in combination with Nd:YAG laser [14]. The bioglass particles of Ca, P, Na, Si, and O of lower than 20 μm reacts rapidly with water and saliva to produce a mineral compound similar to hydroxyapatite crystals that covers the dentin [25] favoring better results on the treatment of dentin sensitivity demonstrated clinically [12]. This was even better following Er:YAG laser application, because the ablated dentin was covered with these crystals to obliterate dentin tubules. In case of continuous acid etching from erosion, the protection of dentin from damage probably occurs. The increasing of Ca/P ratio should be expected if one considers a remineralizing effect of the eroded dentin by the action of Sensodyne Repair and Protect following Er:YAG laser irradiation. However, chemical changes on the molecular level were only described in sound dentin following irradiation with Nd:YAG laser [25], as a result of the evaporation of organic components that increased the relative content of Ca or P, and Er,Cr:YSGG laser [26] that increased the Ca, P, and Mg levels. Our investigation showed the contrary because as the Ca/P ratio decreased after irradiation of Er:YAG laser, probably because water evaporates as a result of the absorption of the Er:YAG laser wavelength and ablation occurs. Our results showed that the Ca/P ratio in the erosion (E) and Sensodyne (ES) groups was higher than that when laser was employed alone. Moreover, no significant difference was found regarding the Ca/P ratio in the laser (EL), Sensodyne + Laser (ESL) and Laser + Sensodyne (ELS) groups, which suggests that the order of the application of laser and the toothpaste did not exert a significant influence on the Ca/P ratio. However, it is not possible to affirm that the dentin underwent remineralization due to the subsequent application of Sensodyne Repair and Protect. Both erosion of an extrinsic (acidic foods, beverages and medications) and intrinsic (stomach acid from gastroesophageal reflux, chronic gastritis, alcohol intake, pregnancy, obesity, hiatus hernia, bulimia and anorexia) is serious [2] and requires complex treatment considering the multifactor etiology and constant acid challenge that affects the structures of the teeth. This study investigated whether the use of

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Sensodyne Repair and Protect with bioglass would complement the action of the Er:YAG laser on eroded dentin. The results of this combination were positive as showed. Other protocols emphasized the use of femtosecond laser irradiation [27, 28] and observed ablation for the removal of dental tissue ensuring that the tooth surface remained intact. But future researches may be continued to evaluate the durability effect of this combined effect and also the microhardness of eroded dentin in the parameters described.

Conclusion

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Based on the findings achieved with the proposed methods, Er:YAG laser followed by the application of Sensodyne Repair and Protect (NovaMin®) is the most promising treatment for dental erosion.

15.

Compliance with ethical standards

16.

Conflict of interest The authors declare that they have no conflict of interest.

17.

Ethics approval Human third molars used in this study following approval from the human research ethics committee (certificate number: 1.209.605).

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References 20. 1.

2.

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8.

Moynihan PJ (2005) The role of diet and nutrition in the etiology and prevention of oral diseases. Bull World Health Organ 83:694– 699 Bartlett DW, Shah P (2006) A critical review of non-carious cervical (wear) lesions and the role of abfraction, erosion, and abrasion. J Dent Res 85:306–312 Lopes AO, Aranha AC (2013) Comparative evaluation of the effects of Nd:YAG laser and a desensitizer agent on the treatment of dentin hypersensitivity: a clinical study. Photomed Laser Surg 31: 132–138 Dantas EM, Dantas PMC, Nóbrega FGO, Vasconcellos RG, Aguiar Junior JN, Queiroz LMG (2013) Low-level laser therapy for treating cervical dentinal hypersensitivity—literature review. Odontol Clín Cient 12:7–11 Hashim NT, Gasmalla BG, Sabahelkheir AH, Awooda AM (2014) Effect of the clinical application of the diode laser (810 nm) in the treatment of dentine hypersensitivity. BMC Res Notes 7:31 Yu CH, Chang YC (2013) Clinical efficacy of the Er:YAG laser treatment on hypersensitive dentin. J Form Med Assoc 113:388–391 Tunar OL, Gursoy H, ÇaKar G, Kuru B (2014) Evaluation of the effects of Er:YAG laser and desensitizing paste containing 8% arginine and calcium carbonate, and their combinations on human dentine tubules: a scanning electron microscopic analysis. Photomed Laser Surg 32:540–545 Namour A, Nammour S, Peremans A, Heysselaer D, De Moor JG (2014) Treatment of dentinal hypersensitivity by means of Nd:YAP laser: a preliminary in vitro study. Sci World J 1:323304

21.

22.

23.

24.

25.

26.

27.

28.

Dilber E, Malkoc LA, Ozturk AN, Ozturk F (2013) Effect of various laser irradiations on the mineral content of dentin. Eur J Dent 7: 74–80 Belal MH, Yassin A (2014) A comparative evaluation of CO2 and erbium-doped yttrium aluminium garnet laser therapy in the management of dentin hypersensitivity and assessment of mineral content. J Periodontal Implant Sci 44:227–234 Han SY, Jung HI, Know HK, Kim BI (2013) Combined effects of Er:YAG laser and nano-carbonate apatite dentifrice on dentinal tubule occlusion: in vitro study. Photomed Laser Surg 31:342–348 Wang Z, Sa Y, Sauro S, Chen H, Xing W (2010) Effect of desensitising toothpastes on dentinal tubule occlusion: a dentine permeability measurement and SEM in vitro study. J Dent 38: 400–410 Wefel JS (2009) NovaMin®: likely clinical success. Adv Dent Res 21:40–43 Farmakis ET, Kozyrakis K, Khabbaz MG, Schoop U, Beer F, Morit A (2012) In vitro evaluation of dentin tubule occlusion by Denshield and neodymium-doped yttrium-aluminum-garnet laser irradiation. J Endod 38:662–666 Trevelin LT, Marques MM, Aranha AC, Arana-Chavez VE, Matos AB (2015) Effect of super short pulse Er:YAG laser on human dentin: scanning electron microscopy analysis. Microsc Res Tech 78:472–478 Zimmerli B, De Munck J, Lussi A, Lambrechts P (2012) Long-term bonding to eroded dentin requires superficial bur preparation. Clin Oral Invest 16:1451–1461 Aranha AC, Pimenta LA, March GM (2009) Clinical evaluation of desensitizing treatments for cervical dentin hypersensitivity. Braz Oral Res 23:333–339 Hibst R, Keller U (1989) Experimental studies of the application of the Er:YAG laser on dental hard substances. I. Measurement of the ablation rate. Lasers Surg Med 9:338–344 Zhao-Zhang L, Code JE, Van de Merwe WP (1992) Er:YAG laser ablation of enamel and dentin of human teeth: determination of ablation rates at various fluences and pulse repetition rates. Lasers Surg Med 12:625–630 Zapletalova Z, Perina JR, Novotny R, Chmelikhova H (2007) Suitable conditions for sealing of open dentinal tubules using a pulsed Nd:YAG laser. Photomed Laser Surg 25:495–499 João-Souza SH, Scaramucci T, Hara AT, Aranha AC (2015) Effect of Nd:YAG laser irradiation and fluoride application in the progression of dentin erosion in vitro. Lasers Med Sci 30:2273–2279 Jelínková H, Dostálová T, Dolezalová L, Krejsa O, Hamal K, Kubelka J, Procházka S (1997) Comparison of preparation speed of En YAG laser and conventional drilling machine. SPIE 2973:2–10 Badran Z, Boutigny H, Struillou X, Baroth S, Laboux O, Assem S (2011) Tooth desensitization with an Er:YAG laser: in vitro microscopical observation and a case report. Lasers Med Sci 26:139–142 Milleman JR, Milleman KR, Clarck CE, Mongiello KA, Simonton TC, Proskin HM (2015) NUPRO Sensodyne prophylaxis paste with NovaMin for the treatment of dentin hypersensitivity: a 4week clinical study. Am J Dent 25:262–268 Altundasar E, Ozcelik B, Cehreli ZC, Matsumoto K (2006) Ultramorphological and histochemical changes after Er,Cr:YSGG laser irradiation and two different irrigation regimes. J Endod 32: 465–468 Ari H, Erdemir A (2005) Effects of endodontic irrigation solutions on mineral content of root canal dentin using ICP-AES technique. J Endod 31:187–189 Menezes RF, Harvey CM, Gerbi MEMM, Smith ZJ, Smith D, Ivaldi JC, Philips A, Chan JW, Wachsmann-Hogiu S (2017) Fslaser ablation of teeth in temperature limited and provides information about the ablated components. J Biophotonics 10:1292–1304 Chung SH, Mazur E (2017) Surgical applications of femtoseconds laser. J Biophotonics 2:557–572