Research Article

The use of a Novel Bioactive Glass in Air Polishing for Subgingival Root Debridement

Sultan DA¹, Hill RG² and Gillam DG²*

¹Centre Immuno-Biology & Regenerative Medicine, London, United Kingdom

¹Oral Bioengineering Barts and the London School of Medicine and Dentistry QMUL, Institute of Dentistry, London, United Kingdom

Submission: October 25, 2019; Published: November 13, 2019

*Corresponding author: David Gillam, Oral Bioengineering, Barts and the London, School of Medicine and Dentistry, Queen Mary University of London, United Kingdom

How to cite this article: Sultan DA, Hill RG, Gillam DG. The use of a Novel Bioactive Glass in Air Polishing for Subgingival Root Debridement. Adv Dent & Oral Health. 2019; 11(4): 555819. DOI:10.19080/ADOH.2019.11.555819

Abstract

Aims: To determine the abrasiveness of using a novel bioactive glass (BioMin™ F) in air polishing for subgingival root debridement by measuring dentine loss and compare this value to the reference powders. Furthermore, to confirm the tubular occlusion effect of air polishing with the bioactive glass using Scanning Electron Microscopy techniques.

Material and Methods: Ivory derived from an elephant’s tusk was used as the study sample. A balled milled BioMin™ F powder (D90 = 87.9 μm), was used as the test powder; This choice was based on a previously performed pilot study [1]. This powder was compared to two reference powders, sodium bicarbonate and glycine. Each powder group constituted of six samples of ivory. The dentine lost was measured in μm using white light profilometry. Scanning electron microscopy was performed for all the tested powders, to evaluate particle shape, and to the study samples to assess the effect of the air abrasive/polishing procedure on dentinal tubules.

Results: The depth of dentine removed (mean ± standard deviation) of the test group, air polishing with the bioactive glass, was 11.0 ± 1.05 μm, control group 1, air polishing with sodium bicarbonate, was 44.1 ± 0.77μm, and control group 2, air polishing with glycine, was 28.1 ± 1.87μm. The differences between the three groups were statistically significant. SEM images showed a partial tubular occlusion effect in the test group, and this was absent in both control groups.

Conclusion: The novel bioactive glass, BioMin™ F, with ball milled particles 90% sized less than 87.9 μm, was significantly more conservative than sodium bicarbonate powder and glycine powder. There was evidence of partial tubular occlusion following bioactive glass air polishing; however, no tubular occlusion was evident in the samples treated with either sodium bicarbonate or glycine air polishing.

Keywords: Novel Bioactive Glass; Air Polishing; Subgingival Root Debridement

Introduction

Periodontal diseases are strongly associated with the presence of bacterial biofilms on root surfaces [2]. Control and removal of bacterial biofilm from all dental surfaces is essential in the treatment and prevention of these diseases [3,4]. It is necessary for periodontal patients to receive frequently performed subgingival debridement in pockets >3 mm probing depth in order to maintain periodontal health since a pre-treatment composition of subgingival microflora can be re-established after several months [5]. The traditional modalities for plaque and calculus removal involve the use of hand instruments or ultrasonic devices or a combination of both. These are both uncomfortable, technically demanding, as well as being clinically time consuming. It may, also lead to severe, substantial, and irreversible root damage [6], and gingival recession over time if applied repeatedly [7,8]. For treatments that need to be repeated, time efficiency, high patient acceptance, and minimal tissue damage are essential requirements [4]. The use of other treatment modalities which are effective in removing plaque with minimal abrasion to root surfaces is preferable [9].

Subgingival air polishing (AP) has been suggested as a simplified alternative approach for root debridement [10]. AP has demonstrated to be a valid, highly efficient, and convenient treatment approach to subgingival debridement [10,11]. It is preferable to conventional treatment with respect to patient comfort, safety, and time efficiency and, therefore, may offer more patient compliance and economic benefits [4,10-14]. Bioactive glasses are biocompatible, non-toxic, non-inflammatory, non-immunogenic bioactive agents having the ability to interact directly with living tissues and form chemical bonds. Once the bioactive glass dissolves, it forms a hydroxyapatite or fluorapatite like phase which, chemically is similar to the natural tooth mineral. AP with hydroxyapatite has been demonstrated to be effective in removing plaque, tartar (calculus), and stains from enamel and cementum surfaces [15]. The treated enamel and cementum surfaces were covered with a layer rich in hydroxyapatite that was not removed by a water spray [15]. This high saturation of superficial enamel and cementum layers with calcium and phosphate supports remineralization of tooth hard tissues and may also reduce dentine permeability by occluding dentinal tubules and thus reduce dentine/ root hypersensitivity [15,16]. The primary aim of this study was to determine the abrasiveness of using a novel bioactive glass BioMin™ F in air polishing for subgingival root debridement by measuring dentine loss and compare this value to the reference powders. A secondary aim was to confirm the tubular occlusion effect of air polishing with the bioactive glass using Scanning Electron Microscopy (SEM) techniques.

Materials and Methods

Sample Preparation

A flat surface pristine ivory dentine (elephant’s tusk) was used as the study sample. An elephant tusk had been previously seized by UK airport customs (illegal smuggling of ivory) and subsequently given to Queen Mary University of London for research use. The tusk was cut manually with a hacksaw in order to obtain a 15 mm thick section of flat surfaces ivory dentine. This was further divided into 18 (10×10 mm) squares. The samples were then mounted in a resin using Claro Cit (Struers ApS, Denmark), which is a cold mounting acrylic resin (Figure 1). The plastic disc was first painted with a thin coat of Vaseline and then the material was used according to the manufacturer’s instructions. After the resin had cured, the sample was polished to an optical finish using a Kemet 3000 LVAC (Kemet International Ltd, Maidstone, Kent, UK) polishing machine using several polishing discs in this order; 360 Grit, 400 Grit, 500 Grit, 800 Grit, 1000 Grit, and lastly 4000 Grit.

Powder Preparation

BioMinF® bioactive glass was obtained from CDL Ltd Stoke, UK in the form of glass frit (a water-quenched granular glass). The glass was Milled first with a Gyro Mill (Glen Creston, London, UK) then ball milled and sieved to give BioMin™ F powder with D90 of 87.9 μm; This was the test powder which was compared to the reference powders, sodium bicarbonate powder (Medivance Ltd, London, UK) and glycine powder (ClinproTM Glycine Prophy Powder, was obtained from 3M TM). Particle size analysis was undertaken for all three powders using a Malvern MASTERSIZER 3000 (Malvern Panalytical, Malvern, UK). SEM images were also taken for each powder.

Experimental Method

An Aqua Care Air Abrasion & Polishing System from Velopex International, Medivance Instruments, Ltd was used in the experiment. The procedure was performed according to manufacturer’s recommendations, a distance of 4 mm, feed rate 1 and air pressure of 80 psi (551.5 kPa). A handpiece with a 0.8 mm tip was used together with disposable plastic tips, both were obtained from Velopex International, Medivance Instruments, Ltd. Plastic tips were changed after each application in order to standardize the experiment. Each sample was air abraded at a 90° angle to the surface for 5 and 10 seconds with the test powders. The amount of powder present in the Powder chamber was checked and always filled to the same level before each application to ensure reproducible and standardized conditions. After the experiment, the substance loss/cutting depth of each sample was evaluated using White Light Profilometry. A Proscan 2000 by Scantron Industrial Products ltd was used to scan each sample individually. SEM images of each sample were taken to confirm any tubular occlusion effect on the dentine surface. The samples were coated with a layer of silver (Agar Scientific Ltd, UK) to prepare it for SEM.

Results

White Light Profilometry Analysis

Statistical analysis was based on the comparison between the three treatment groups. Differences in cut depth or dentine loss were tested by the use of the Independent Samples t-test. A P-value <0.05 was considered statistically significant. Data handling and statistical testing were performed with the use of the Microsoft Excel software. The individual cut depth values, in μm, of the test and control samples, following 5 seconds of air polishing, are shown in Table 1 & Figure 2. The mean ± standard deviation of the cut depth of the test group was 11.0 ± 1.05 μm; this was significantly less than the mean ± standard deviation cut depth of the control group 1 (sodium bicarbonate) which was 44.1 ± 0.77 μm, and control group 2 (glycine) which was 28.1 ± 1.87 μm.

Furthermore, the difference in the cut depth values between the two control groups were statistically significant. Air polishing with the novel bioactive glass, BioMin™ F, resulted in statistically significant less cut depth and dentine loss compared to air polishing with sodium bicarbonate or glycine for the same duration (P <0.05). Thus, the null hypothesis, which stated that there was no significant difference in the cut depths between the three powders, was rejected. The small value of the standard error of the mean of all groups, 0.43 for the test group, 0.31 for the control group 1, and 0.76 for control group 2, can indicate the reliability of the means and that these means are more accurate reflection of the actual true mean. The 95% confidence interval values of all groups are shown in Table 2 and indicates that we are 95% confident that the true actual mean of each group lies within this range.

Scanning Electron Microscopy Images Evaluating Dentinal Tubules

The surface characteristics of ivory samples of each group were assessed under the scanning electron microscope at a magnification of x10000 at two different points of the experiment:

a) Before air polishing.

b) After 5 seconds of air polishing application with the test or control powders.

Extra images at a reduced magnification of x1000 were further used to view each ivory sample at the same points of the experiment. The rationale behind this was to complement the result seen at the higher magnification and to allow for observation of any tubule occlusion at a wider landscape of view. Also, at this reduced magnification, the dentine tubules appear smaller, thereby increasing the effective field of view which enabled better observation of the spread of the surface deposition. All observations were assessed using the naked eye of the author without any adjunctive aids. For ease of data analysis, the results will be presented individually, for each group before they are compared with each other.

Control Group 1 & 2 (Air Polishing with Sodium Bicarbonate and Glycine)

Figures 3 & 4 represent the surface of ivory dentine before the air polishing procedure, i.e. the normal state of ivory dentine. These figures show a clear surface with zero tubule occlusion, featuring opened dentine tubules. Figure 5 was taken following 5 seconds of air polishing with sodium bicarbonate; the dentine surface showed no sign of tubule occlusion and appeared almost similar to the previous image (Figure 6). A similar finding was observed following 5 seconds of glycine air polishing (Figure 7). At a lower magnification, ×1000, the post-operative images, Figures 6 & 8, show the development of cracks or microfractures connecting the dentinal tubules. These were not present or were only minimally present in the pre-operative image, Figure 4.

Test Group (Air Polishing with Bioactive Glass)

Figure 9 shows the untreated ivory dentine surface with clear, well-defined, and open dentine tubule margins (Figure 10). SEM analysis of the treated dentine surface with the novel bioactive glass air polishing showed surface structural changes most probably caused by apatite deposition (Figure 11). A narrowing of the dentinal tubules and some tubular occlusion were observed together with scattered deposits on the surface, indicating the formation of an apatite rich smear layer. At the lower magnification, a similar observation to that observed in the control group was also evident in the test group. Cracks and microfractures between the dentinal tubules developed following the application of air polishing (Figure 12); these were not present in the pre-operative image and were probably due to shrinkage effects within the SEM following water loss (Figure 10).

Discussion

The rationale for using pristine ivory dentine (elephant’s tusk) in this study may be justified by references to several studies where it was demonstrated that calcium and phosphate ratios were comparable to other animal models [17] as well as the human tooth [18]. The impact of solid particles on the treated surface is the basic event leading to substance removal using air polishing with a water slurry cutting element [19]. This abrasive process is affected by many factors, such as the properties of the applied powder [1], time of exposure, and some parameters of the air polishing device itself (Pressure and Feed Rate) are also influential, such as water pressure and powder emission rate [19- 22]. To the best of our knowledge, there are no previous published studies on the abrasive effect of bioactive glass air polishing, used for debridement, on the root or dentine surfaces. Also, there are no published investigations that directly compare the cut depth following bioactive glass air polishing with either sodium bicarbonate or glycine air polishing used for tooth surface debridement. Two previous studies had investigated the effect of bioactive glass air abrasion, used for cavity preparation and caries removal, on the dentine surface [23,24]. The air abrasion unit, bioactive glass powder characteristics, and experimental settings such as application time, distance pressure were, however, completely different from our study. Therefore, direct comparison between the present study results and previous results are not valid.

The tubular occlusion effect due to the deposition of apatite minerals in the dentinal tubules with the formation of a surface smear layer was observed in our study following bioactive glass air polishing in agreement with other studies that examined the tested surface following bioactive glass application. Litkowski et al. [25] evaluated the dentine surface after treatment with bioactive glass compounds and reported an increase in tubular occlusion compared with non-bioactive glass containing controls [25]. Furthermore, Wang et al. [26] demonstrated that dentine remineralization and complete occlusion of dentinal tubules was evident after bioactive glass treatment [26]. In addition, Sauro et al. [16] concluded that air polishing with bioactive glass powder reduced dentine permeability and created a dentine surface resistant to citric acid attack, thereby indicating that the procedure was suitable for the treatment of dentinal hypersensitivity [16]. This was further confirmed in in vivo studies where patients reported decreased dental sensitivity immediately following bioactive glass air polishing and up to 10 days following the procedure. On the other hand, patients reported increased sensitivity immediately following air polishing with sodium bicarbonate and up to 10 days following the procedure [27]. Also, the bioactive glass appeared to offer a more effective tooth whitening effect when compared to sodium bicarbonate and patients reported increase in comfort of procedure with the bioactive glass over that when using sodium bicarbonate [27].

Studies had also demonstrated that the use of bioactive glass was more beneficial to the tooth surface compared to sodium bicarbonate. In vitro studies confirmed the formation of apatite rich smear layer on enamel, dentine and cementum surfaces following bioactive glass application; thus, it supports regeneration and remineralization of dental tissues [26,28-31]. Taha et al reported the remineralization of enamel white spot lesions following air polishing with a fluoride containing bioactive glass [30]. Another group confirmed that pre-conditioning enamel white spot lesion surfaces using bioactive glass air abrasion enhanced the subsequent remineralization therapy [32]. Coupled to this remineralising effect, bioactive glasses have been shown to have an antibacterial effect on oral flora [33,34]. The microfractures and cracks that developed within the ivory samples following air polishing with the tested powders in the present study can be attributed to the dry nature of the tusk as the tusk was stored in dry air.

The mean cut depth following 5 seconds of glycine air polishing in the present study was 28.1 ± 1.87 μm, which was comparable to the abrasion data obtained by Buhler et al. [21], who reported on a defect depth of 27.56 ± 3.01 μm following a 5 second application of glycine powder but at a 45° angle [35]. The results from the present study are also comparable to the results of Herr et al, who reported a defect depth of 31 ± 28 μm following 5 seconds of glycine air polishing at a 45° angle [36]. Several studies have compared the effect of glycine air polishing to sodium bicarbonate air polishing. There is a general agreement that sodium bicarbonate was more abrasive on dental tissues than glycine. The resultant defect depth was significantly greater following sodium bicarbonate air polishing compared to glycine air polishing for the same duration [35,37,38].

Therefore, the present study is comparable to previous investigations. The mean defect depth following 5 seconds of sodium bicarbonate air polishing was 44.1 ± 0.77 μm, which agrees with previous reports [39], and, similarly, the difference in the resultant defect depths following glycine and sodium bicarbonate air polishing was statistically significant. The softer effect of glycine air polishing was also evident on the gingival tissues. Glycine air polishing has been reported to cause less gingival erosion compared to sodium bicarbonate air polishing and hand instrumentation [40]. This can partially explain the increased patient comfort reported following glycine air polishing compared to the other procedures [37]. The present study showed that air polishing with the smallest ball milled BioMinF particles, D90 of 87.9 μm, was significantly less abrasive than the reference powders, sodium bicarbonate and glycine. However, the efficacy of this novel bioactive glass powder in removing plaque from dental surfaces has yet to be confirmed. An In vivo study will be required in order to confirm this de-plaquing effect and determine the clinical effectiveness of using a BioMin™ F powder in an air polishing procedure.

References

1. Sultan D, Hill RG, Gillam D (2018) The use of a novel bioactive glass in air polishing for root debridement: a pilot study. J Clin Periodontol 45(S19): 292.
2. Lindhe J, Nyman S, Karring T (1982) Scaling and root planing in shallow pockets. J Clin Periodontol 9(5): 415-418.
3. Serrano J, Escribano M, Roldan S, Martin C, Herrera D (2015) Efficacy of adjunctive anti-plaque chemical agents in managing gingivitis: a systematic review and meta-analysis. J Clin Periodontol 42(Suppl16): S106-S138.
4. Moene R, Decaillet F, Andersen E, Mombelli A (2010) Subgingival plaque removal using a new air-polishing device. J Periodontol 81(1): 79-88.
5. Axelsson P, Lindhe J, Nystrom B (1991) On the prevention of caries and periodontal disease. Results of a 15-year longitudinal study in adults. J Clin Periodontol 18(3): 182-189.
6. Zappa U, Smith B, Simona C, Graf H, Case D, et al. (1991) Root substance removal by scaling and root planing. J Periodontol 62(12): 750-754.
7. Badersten A, Nilveus R, Egelberg J (1984) Effect of nonsurgical periodontal therapy. II. Severely advanced periodontitis. J Clin Periodontol 11(1): 63-76.
8. Badersten A, Nilveus R, Egelberg J (1981) Effect of nonsurgical periodontal therapy. I. Moderately advanced periodontitis. J Clin Periodontol 8(1): 57-72.
9. Wennström JL, Dahlén G, Ramberg P (2011) Subgingival debridement of periodontal pockets by air polishing in comparison with ultrasonic instrumentation during maintenance therapy. J Clin Periodontol 38(9): 820-807.
10. Petersilka GJ, Steinmann D, Haberlein I, Heinecke A, Flemmig TF (2003) Subgingival plaque removal in buccal and lingual sites using a novel low abrasive air-polishing powder. J Clin Periodontol 30(4): 328-333.
11. Petersilka GJ, Tunkel J, Barakos K, Heinecke A, Haberlein I, et al. (2003) Subgingival plaque removal at interdental sites using a low-abrasive air polishing powder. J Periodontol 74(3): 307-311.
12. Kargas K, Tsalikis L, Sakellari D, Menexes G, Konstantinidis A (2015) Pilot study on the clinical and microbiological effect of subgingival glycine powder air polishing using a cannula-like jet. Int J Dent Hyg 13(3): 161-169.
13. Hagi TT, Hofmanner P, Salvi GE, Ramseier CA, Sculean A (2013) Clinical outcomes following subgingival application of a novel erythritol powder by means of air polishing in supportive periodontal therapy: a randomized, controlled clinical study. Quintessence Int 44(10): 753-761.
14. Hagi TT, Hofmanner P, Eick S, Donnet M, Salvi GE, et al. (2015) The effects of erythritol air-polishing powder on microbiologic and clinical outcomes during supportive periodontal therapy: Six-month results of a randomized controlled clinical trial. Quintessence Int 46(1): 31-41.
15. Janicki T, Sobczak-Kupiec A, Skomro P, Wzorek Z (2012) Surface of root cementum following air-polishing with bioactive hydroxyapatite (Ca and P mapping). A pilot studies. Acta Bioeng Biomech 14(1): 31-38.
16. Sauro S, Watson TF, Thompson I (2010) Dentine desensitization induced by prophylactic and air-polishing procedures: an in vitro dentine permeability and confocal microscopy study. J Dent 38(5): 411-422.
17. Nganvongpanit N, Brown JL, Buddhachat K, Somgird C, Thitaram C (2016) Elemental Analysis of Asian Elephant (Elephas maximus) Teeth Using X-ray Fluorescence and a Comparison to Other Species. Biol Trace Elem Res 170(1): 94-105.
18. Kouadio A-A, Struillou X, Bories C, Bouler J-M, Badran Z, et al. (2017) An in vitro analysis model for investigating the staining effect of various chlorhexidine-based mouthwashes. J Clin Exp Dent 9(3): e410-416.
19. Momber AW, Kovacevic, Radovan (1998) Principles of Abrasive Water Jet Machining. London, UK.
20. Kozlovsky A, Artzi Z, Nemcovsky CE, Hirshberg A (2005) Effect of air-polishing devices on the gingiva: histologic study in the canine. J Clin Periodontol 32(4): 329-334.
21. Buhler J, Amato M, Weiger R, Walter C (2016) A systematic review on the patient perception of periodontal treatment using air polishing devices. International Journal of Dental Hygiene 14(1): 4-14.
22. Petersilka GJ, Bell M, Häberlein I, Mehl A, Hickel R, et al. (2003) In vitro evaluation of novel low abrasive air polishing powders. J Clin Periodontol 30(1): 9-13.
23. Paolinelis G, Banerjee A, Watson TF (2008) An in vitro investigation of the effect and retention of bioactive glass air-abrasive on sound and carious dentine. J Dent 36(3): 214-218.
24. Tan MHX, Hill RG, Anderson P (2015) Comparing the Air Abrasion Cutting Efficacy of Dentine Using a Fluoride-Containing Bioactive Glass versus an Alumina Abrasive: An In Vitro Study. International Journal of Dentistry 2015: 521901.
25. Litkowski LJ HG, Sheaffer HB, Greenspan DC (1997) Occlusion of Dentine Tubules by 45S5 Bioglass. Bioceramics 10: 411-414.
26. Wang Z, Jiang T, Sauro S, Wang Y, Thompson I, Watson TF, et al. (2011) Dentine remineralization induced by two bioactive glasses developed for air abrasion purposes. J Dent 39(11): 746-756.
27. Banerjee A, Hajatdoost-Sani M, Farrell S, Thompson I (2010) A clinical evaluation and comparison of bioactive glass and sodium bicarbonate air-polishing powders. J Dent 38(6): 475-479.
28. Slim La TC (2011) Air polishing revisited.
29. Hench LL (2006) The story of Bioglass. J Mater Sci Mater Med 17(11): 967-978.
30. Taha AA, Fleming PS, Hill RG, Patel MP (2018) Enamel Remineralization with Novel Bioactive Glass Air Abrasion. J Dent Res 97(13): 1438-1444.
31. Farooq I, Tylkowski M, Muller S, Janicki T, Brauer DS, et al. (2013) Influence of sodium content on the properties of bioactive glasses for use in air abrasion. Biomed Mater 8(6): 065008.
32. Milly H, Festy F, Andiappan M, Watson TF, Thompson I, et al. (2015) Surface pre-conditioning with bioactive glass air-abrasion can enhance enamel white spot lesion remineralization. Dent Mater 31(5): 522-533.
33. Stoor P, Soderling E, Salonen JI (1998) Antibacterial effects of a bioactive glass paste on oral microorganisms. Acta Odontol Scand 56(3): 161-165.
34. Allan I, Newman H, Wilson M (2001) Antibacterial activity of particulate bioglass against supra- and subgingival bacteria. Biomaterials 22(12): 1683-1687.
35. Buhler J, Schmidli F, Weiger R, Walter C (2015) Analysis of the effects of air polishing powders containing sodium bicarbonate and glycine on human teeth. Clinical Oral Investigations 19(4): 877-885.
36. Herr ML, DeLong R, Li Y, Lunos SA, Stoltenberg JL (2017) Use of a continual sweep motion to compare air polishing devices, powders and exposure time on unexposed root cementum. Odontology 105(3): 311-319.
37. Petersilka GJ (2011) Subgingival air-polishing in the treatment of periodontal biofilm infections. Periodontol 2000 55(1): 124-142.
38. Tada K, Kakuta K, Ogura H, Sato S (2010) Effect of particle diameter on air polishing of dentin surfaces. Odontology 98(1): 31-36.
39. (2007) MD Powder for Sub- and Supragingival Plaque Removal Using Powder Stream Devices Clinpro Prophy Powder Technical Product Profile. Seefeld, Germany. 3M ESPE.
40. Petersilka G, Faggion CM, Stratmann U, Gerss J, Ehmke B, et al. (2008) Effect of glycine powder air-polishing on the gingiva. J Clin Periodontol 35(4): 324-332.