Comparison of Nano-Hydroxyapatite and Sodium Fluoride Mouthrinse For

Original Article

Comparison of Nano-Hydroxyapatite and Sodium Fluoride

Mouthrinse for Remineralization of Incipient Carious Lesions

Roza Haghgoo1, Mohammad Bagher Rezvani2, Mehdi Salehi Zeinabadi3

1Associate professor, Department of Pediatric, Dental School , Shahed University, Tehran, Iran 2Assistant professor, Department of Restorative, Dental School , Shahed University, Tehran, Iran 3Postgraduate Student, Department of Pediatric Dentistry, Shahed University, Tehran, Iran

Abstract Objective: Dental caries is an infectious disease that can be prevented in several ways. The aim of this study was to compare the efficacy of sodium fluoride mouthrinse and nano- hydroxyapatite (nano-HA) for the remineralization of incipient caries. Materials and Methods: After obtaining different concentrations of nano-HA (0- 2-5-10%), 60 sound premolars fixed in acrylic blocks were coated with nail polish except for one surface. Ten teeth (control group) were stored in distilled water and the remaining 50 samples were demineralized by immersion in 13 ml of 0.1 M lactic acid and 0.2% poly acrylic acid for 48 hours. Their microhardness was then measured and compared to that of the control group. Next, the 50 test teeth were randomly divided into 5 groups of group1 (negative), group 2 (2% nano-HA), group 3 (5% nano-HA), group 4(10% nano-HA) and group 5 (0.2 NAF mouthrinse). The microhardness of the teeth was measured after 12 hours of immersion in the above-mentioned solutions. Data were analyzed using repeated measures analysis of variance (ANOVA).

Results: Microhardness of all samples decreased significantly after immersion in

 Corresponding author: the demineralization solution and increased following immersion in nano-HA and M. Salehi Zeinabadi, Depart- NAF mouthrinses; however, this increase was not statistically significant ment of Pediatric Dentistry, (P=0.711). Shahed Dental School, Tehran, Conclusion: Nano-HA and NAF mouthrinses can greatly enhance remineraliza- Iran Archivetion and increase tooth microhardness of. SID [email protected] Key words: Nano-hydroxyapatite; Tooth Remineralization; Sodium Fluoride

Received: 22 February 2014 Accepted: 19 June 2014 Journal of Dentistry, Tehran University of Medical Sciences, Tehran, Iran (2014; Vol. 11, No. 4)

INTRODUCTION HA. The critical pH for enamel dissolution is Dental caries is an infectious disease and its about 5.5 [1]. Although several methods such initiation and progression depend on several as local/systemic fluoride therapy, diet control factors. In a balanced oral environment, saliva and use of fissure sealants are used to prevent contributes to tooth remineralization by sup- dental caries, they are not efficient enough to plying mineral components necessary to form completely prevent tooth decay [2].

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www.SID.ir Journal of Dentistry, Tehran University of Medical Sciences Haghgoo et. al Hydroxyapatite is an important biomaterial MATERIALS AND METHODS and a major component of the mineralized In this experimental study, nano-HA (Nano- structure of the teeth and bones [3-5]. It is also shel Co., USA) was added to distilled water in an important bioceramic for medical and den- predetermined weight percentages (0, 2, 5, tal applications (including dental implants, 10%) in order to prepare nano-HA mouth- orthopedics, alveolar reconstruction and drug rinses of different concentrations. delivery systems) due to its biocompatibility Sound premolars extracted for orthodontic and biological and chemical similarity to the purposes were collected and fixed in acrylic bone structure [6]. blocks. After cleaning and polishing the teeth, HA can be used for bone, cementum and ar- all surfaces were coated with nail polish, ex- tificial root formation and can induce tooth cept for one surface. Ten teeth were randomly remineralization. With the development of na- selected as controls and stored in distilled wa- notechnology, nano-HA particles are exten- ter during the study. Eventually, Vickers hard- sively studied in the fields of biomaterials and ness number (VHN) of all samples was meas- medicine. ured using Vickers microhardness tester (Shi- Compared to typical HA, nano-HA has some madzu M g5037, Japan). unique properties such as higher solubility, In order to develop artificial caries, the sam- higher surface energy and optimal biocompa- ples were immersed in 13 ml of 0.1 M lactic tibility. Substituting bone and tooth with have acid and 0.2 M poly acrylic acid with a pH of several advantages including high toughness, 5. After demineralization, VHN was measured high strength, high density, long shelf life and by applying 200gr force. Then, the samples optimal biocompatibility [7]. were randomly divided into 5 groups (one Moreover, it has been reported that nano-HA group was exposed to NaF mouthrinse and the particles have superior bioactivity compared to remaining 4 to nano-HA mouthrinses of dif- larger crystals [8]. ferent concentrations). For the initiation of In spite of the reports of HA application in remineralization, all teeth were immersed in various fields of medicine, only a few studies artificial saliva for 12 hours [10] before the have evaluated the relationship between nano- microhardness testing. Then, 4 groups were HA and dental caries. prepared as follows: Results of a study comparing the remineraliza- Group 1: 10 teeth were immersed in distilled tion effect of combined nano-HA and sodium- water (negative control group) for 12 hours. fluoride (NaF) on primary carious lesions Group 2: 10 teeth were immersed in distilled showed that the greater the amount of nano- water plus 2% nano-HA for 12 hours. HA in NaF mouthrinse, the higher the remine- Group 3: 10 teeth were immersed in distilled ralization of enamel. They suggested a syner- water plus 5% nano-HA for 12 hours. getic role for nano-HA combined with a fluo- Group 4: 10 teeth were immersed in distilled ridated mouthrinse [2].Archive water plusof 10% nanoSID-HA for 12 hours. Another study evaluated the effect of nano- Group 5: 10 teeth were immersed in 0.2 % HA solution on erosive lesions and showed NaF mouthrinse (Behsa Co.) for 12 hours. that enamel microhardness (decreased due to Finally, the difference in VHN was calculated erosive lesion) enhanced significantly after in each group and data were analyzed using exposure to nano-HA solution [9]. repeated measures ANOVA. P-values less The purpose of this study was to compare the than 0.05 were considered significant. Statis- remineralization effect of nano-HA and NaF tical analysis was done using SPSS 20 for mouthrinses on the initial carious lesions. windows (Chicago, IL, USA)

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www.SID.ir Haghgoo et. al Comparison of Nano-Hydroxyapatite and Sodium Fluoride… RESULTS DISCUSSION The mean baseline microhardness in the 5 Dental caries is the most common chronic dis- groups (control, 2% nano-HA, 5% nano-HA, ease in childhood. It develops as the result of 10% nano-HA and NaF mouthrinse) was the function of cariogenic microorganisms on 349.5, 351.5, 373, 379.1 and 369.2 Gpa, re- fermentable carbohydrates. spectively and it decreased to 86.7, 65.8, 74.2, Tooth decay can be prevented by the elimina- 119.4 and 127.8 after immersion in cariogenic tion of etiologic factors. Saliva can greatly solution, respectively. After demineralization, help in this respect [1]. the teeth were immersed in distilled water, Use of nano-HA mouthrinse is one way to NaF and different concentrations of nano-HA prevent dental caries. Nano-HA is a calcium- mouthrinses. The microhardness of each group phosphate compound with a similar structure was as follows: to that of the mineralized part of dentin and Group 1= 60.9, group 2= 78, group 3= 81, enamel and has the potential to remineralize group 4= 199 and group 5= 128.1. Repeated initial carious lesions [11]. It is bioactive and measures ANOVA showed that the micro- biocompatible [12]. Our study results revealed hardness values decreased in the test groups no significant difference between the effect of (repeated factor P value <0.001) but the mag- various concentrations of nano-HA and NaF nitude of reduction was not significantly dif- mouthrinses on initial carious lesions. Huang ferent between the groups (interaction P val- examined the effect of Galla Chinensis com- ue=0.615). bined with nano-HA on the remineralization The before and after microhardness values of primary lesions and showed that the in- were not significantly different between the crease in enamel microhardness following the groups either (between subject P val- application of these materials was greater than ue=0.142). Table 1 shows the mean micro- distilled water [13]; which confirms our re- hardness of each group before the induction of sults. However, we compared the effect of dif- caries, after the induction of caries and after ferent concentrations of nano-HA on the remi- immersion in the mouthrinses. neralization of initial lesions in human teeth. Figure 1 shows the mean microhardness of Huang evaluated the remineralization effect of each group, before the induction of caries (1), nano-HA on animal teeth by means of measur- after the induction of caries (2) and after im- ing the surface and cross-sectional microhard- mersion in the mouthrinses (3). ness by polarized light microscopy.

Table 1. The mean microhardness of groups before the induction of caries, after the induction of caries and after immersion in the mouthrinses

Group VHN1 VHN2 VHN3

Mean 349.50 86.70 88.70 1 Archive of SID Std. Deviation 36.939 102.557 128.209 Mean 379.10 74.20 97.10 2 Std. Deviation 31.543 88.473 107.075 Mean 374.00 119.44 124.20 3 Std. Deviation 59.703 104.703 110.811 Mean 369.20 127.80 128.40 4 Std. Deviation 63.894 128.156 119.502 Mean 351.50 65.80 77.78 5 Std. Deviation 42.735 71.456 99.516 Mean 364.66 94.29 103.76 Total Std. Deviation 48.168 99.607 110.720 www.jdt.tums.ac.ir July 2014; Vol. 11, No. 4 4038

www.SID.ir Journal of Dentistry, Tehran University of Medical Sciences Haghgoo et. al The results showed that nano-HA enhanced CONCLUSION mineral apposition of surface enamel and was This study showed that both nano-HA and able to repair enamel lesions [14]. We also NaF mouthrinses can greatly enhance remine- concluded that remineralization of primary ralization and increase tooth microhardness. enamel lesions increased with the use of different nano-HA concentrations. The results of ACKNOWLEDGMENTS a study conducted by Min demonstrated that The authors appreciate the assistance of Dr. erosive enamel lesions were repaired effec- Nazila Ameli (postgraduate student of ortho- tively by the use of 0.25% nano-HA [15]; dontics, Shahid Beheshti Dental School) for these findings are in accordance with our re- her kind efforts. sults. However, Min used cone-focal laser scanning and scanning electron microscopy on REFERENCES animal teeth. 1- McDonald Ralph E, Avery David R, Dean Mensinkai and Mathews assessed the effect of Jeffry A. Dentistry for the child and adoles- different types of fluoride mouthrinses on ero- cent.2011,9th ed. sive lesions. 2- Xiangcai M, Xingyi LI, Kuilong LU. Study The results of both studies revealed that fluo- of Nano-Hydroxyapatite on the Remineraliza- ride mouthrinses were advantageous for lesion tion of Dismineralized Teeth. J Materials remineralization; which is consistent with our Science Forum 2005 475-479 : 2423-2426 study results [16, 17]. 3- Kenney EB, Lekovic V, Han T, Carranza Haghgoo studied the remineralization of ero- FA Jr., Dimitrijevic B. The use of a porous sive lesions using nano-HA. The results dem- hydroxyapatite implant in periodontal defects. onstrated that the microhardness of deminera- I. Clinical results after six months. J Periodon- lized enamel increased following the applica- tol 1985; 56: 82-88. tion of nano-HA [9]. It is in agreement with 4-Hench L.L.J. Am. Bioceramics. Ceram. Soc. our result but we compared different nano-HA Vol. 81.1998. p. 1705. concentrations with NaF mouthrinse. 5- Gomez-Vega JM1, Saiz E, Tomsia AP, Kim compared the remineralization effect of Marshall GW, Marshall SJ. Bioactive glass nano-HA combined with NaF mouthrinse and coatings with hydroxyapatite and Bioglass concluded that nano-HA has a synergetic role particles on Ti-based implants. 1. Processing. in dental remineralization [2]; this result is Biomaterials. 2000 Jan;21(2):105-11. consistent with ours. Huang investigated the 6- Kui Long Lu, Xiang Cai Meng, Jiu Xing effects of nano-HA on the remineralization of Zhang, Xing Yi Li, Mei Ling Zhou. Inhibitory initial enamel lesions and found that nano-HA effect of synthetic Nano Hydroxyapatite on has a remineralization potential for initial dental caries. Key Engineering Materials enamel lesions and this finding is similar to 2007; 1538: 336-38. our results [18]. However,Archive we studied the re- 7- Suchanek of W, YoshimuraSID M. Processing and mineralization potential of nano-HA mouth- properties of hydroxyapatite-based biomate- rinse on human enamel using VHN and this is rials for use as hard tissue replacement im- the main difference between our study and plants. J Mater Res. 1998; 13(1):94-117. Huang’s investigation. In our study, human 8- Webster TJ, Ergun C, Doremus RH, Siegel teeth were used as samples, but one limitation RW, Bizios R. Enhanced osteoclast-like cell was to collect premolar teeth only. functions on nano-phase ceramics. Biomate- We suggest further studies to determine the rials. 2001 Jun;22(11):1327-33. effect of these solutions on lesion depth and 9- Haghgoo R, Abbasi F, Rezvani MB. Evalu- various parts of lesions. ation of the effect of nano hydroxyapatite on

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www.SID.ir Haghgoo et. al Comparison of Nano-Hydroxyapatite and Sodium Fluoride… erosive lesions of the enamels of permanent ralization potential of nano-hydroxyapatite on teeth following exposure to soft beer invitro. initial enamel lesions: an in vitro study. Caries Scientific Research and Essays 2011; 6(26): Res. 2011;45(5):460-8. 5933- 5936. 15- Min JH, Kwon HK, Kim BI. The addition 10- Kim M.Y, Kwon H.K, Choi C.H, Kim B.I. of nano-sized hydroxyapatite to a sports drink Combined effects of nano-hydroxyapatite and to inhibit dental erosion: in vitro study using NaF on remineralization of early caries lesion. bovine enamel. J Dent. 2011 Sep;39(9):629- Key Engineering Materials 2007; 1347: 330-2. 35. 11- Dorozhkin S.V. Calcium orthophosphates 16- Mensinkai PK, Ccahuana-Vasquez RA, in dentistry. J Mater Sci: Mater Med 2013; 24: Chedjieu I, Amaechi BT, Mackey AC, Walker 1335-63. TJ, et al. In situ remineralization of white-spot 12- Mohammadi Basir M, Ataei M, Bagher enamel lesions by 500 and 1,100 ppm F denti- Rezvani M, Golkar P. Effect of incorporation frices. Clin Oral Investig. 2012 Aug; of various amounts of nano-sized hydroxyapa- 16(4):1007-14. tite on the mechanical properties of resin- 17- Mathews MS, Amaechi BT, Ramalingam modified glass ionomer. Beheshti Univ Dent J. K, Ccahuana-Vasquez RA, Chedjieu IP, 2013; 4: 216-223. Mackey AC, et al. In situ remineralization of 13- Huang S, Gao S, Cheng L, Yu H. Com- eroded enamel lesions by NaF rinses. Arch bined effects of nano-hydroxyapatite and Gal- Oral Biol. 2012 May;57(5):525-30. la chinensis on remineralization of initial 18- Huang S, Gao S, Cheng L, Yu H. Remine- enamel lesion in vitro. J Dent. 2010 ralization potential of nano-hydroxyapatite on Oct;38(10):811-9. initial enamel lesions: an in vitro study. Caries 14- Huang S, Gao S, Cheng L, Yu H. Remine- Res. 2011;45(5):460-8).

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