ORIGINAL ARTICLE M Becker J Ciupka T Pierchalla KR Fischer A Friedmann Does chemical preconditioning contribute to the effectiveness of scaling and root planing? An in vitro pilot investigation M Becker, J Ciupka, T Pierchalla, KR Fischer, A Friedmann, Department of Periodontology, School of Dentistry, Witten/ Herdecke University, Witten, Germany Abstract: Objectives: A solution based on hypochlorite and amino acids was introduced to improve cleaning efficacy on the root surfaces. The purpose of this in vitro pilot study was to evaluate the time reduction and number of strokes required to clean untreated root surfaces in vitro. Methods: Sixty extracted human teeth displaying areas with subgingival calculus were assigned equally to one of three treatment groups (n = 20) according to the size of occupied areas, estimated by the number of pixels. The groups were assigned to either 30 s penetration time (I) or 300 s (II) or no pretreatment application (III). The weight for instrumentation was calibrated for a M25A curette (Deppeler/Switzerland) with 500 g. A new set of tools was used for each group, and each instrument was sharpened after single use by an EasySharp Device (Deppeler/Switzerland). Results: The time (in seconds) for instrumentation was recorded as follows: Group I: 32/23.5/50 (median/first quartile/third quartile); group II: 33/ 20/52.5; group III: 46.5/35.5/52.3. The results for the numbers of strokes were: Group I: 18/14.3/28; group II: 18.5/13/30.5; group III: 17.5/15/25. No statistically significant differences (P < 0.05) were found between the three groups for the variables ‘time’ and ‘number of strokes’. Conclusions: Within the limits of this in vitro pilot study, preconditioning of the calculus on root surfaces with an alkaline solution failed to reduce the number of strokes and time of instrumentation significantly. Correspondence to: Matthias Becker Department of Periodontology School of Dentistry Witten/Herdecke University Alfred-Herrhausen-Straße 50 58455 Witten Germany Tel.: 0049 2302 926608 Fax: +49 2302 926661 E-mail: Matthias.Becker@uni-wh.de Key words: debridement; dental calculus; dental scaling; root planing Introduction Dates: Accepted 25 October 2016 To cite this article: Int J Dent Hygiene DOI: 10.1111/idh.12264 Becker M, Ciupka J, Pierchalla T, Fischer KR, Friedmann A. Does chemical preconditioning contribute to the effectiveness of scaling and root planing? An in vitro pilot investigation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Scaling and root planing (SRP) is a commonly used method for removing subgingival biofilm and calculus; both are considered the primary etiologic agents in periodontal disease. Subgingival calculus is one of the factors which contribute to the cyclical nature of periodontal disease (1). The removal of these etiologic factors is not only an essential prerequisite for treatment success, but also represents a major challenge in treating poorly accessible areas such as deep pockets, shallow defects, and in particular, teeth with furcation involvement. Following SRP by means of ultrasonic devices and universal curettes, Sherman and co-workers analyzed the outcome by checking for residual calculus clinically and microscopically. Although the clinical examination revealed no remnants, 77.4% of surfaces showed residual calculus when assessed by stereomicroscope after extraction of the teeth (2). Allen and colleagues showed that Int J Dent Hygiene | 1 Becker et al. Effectiveness of calculus preconditioning on SRP autoclaved dental calculus still exerted a toxic effect on the surrounding tissue cells and stated the importance of early and complete calculus removal. They concluded that even sterile calculus remains an irritant to the surrounding tissues (3). However, the role of residual calculus on periodontal health still remains an object of discussion. Sherman and Coworkers showed that changes in gingival bleeding, probing pocket depths and probing attachment levels were not related to remaining calculus 3 months after thorough SRP (4). It has also been stated that thin areas of calculus veneers may be compatible with the formation of epithelial attachment (5). In the 1950s, the adjunctive application of concentrated sodium hypochlorite solution during gingival curettage was reported with contradictory results. Some authors argued that the action of hypochlorite solution was limited specifically to the epithelial lining in the pocket, while others claimed that the solution had an unspecific necrotizing impact on the periodontal tissues (6–8). Since the use of chemical agents was proven to be effective in soft tissue curettage, various chemical solutions have also been proposed for supporting the root debridement, since nowadays soft tissue curettage is no longer indicated in non-surgical periodontal treatment (9, 10). There is a continuing interest in the adjunctive use of chemical agents detoxifying the root surfaces, thereby achieving a more favourable environment for the re-organization of periodontal attachment. Highly concentrated alkaline solution alone or in combination with citric acid neutralization was tested successfully in enhancing degradation of endotoxins by hydrolysis (9, 11). In contrast, sole antiformin, a highly alkaline solution from sodium hypochlorite, sodium carbonate and sodium hydroxide was less effective in removing surface debris after SRP and showed an effect for root surface debridement similar to the control group treated with distilled water (12). Ready-to-use solutions are claimed to be helpful adjuncts in facilitating root debridement. Recently, a low viscous solution (PerisolvTM; RLS Global AB, Gothenburg, Sweden) was launched which is claimed to facilitate SRP. According to the manufacturer‘s information, this solution contains three different amino acids (glutamic acid, leucine and lysine), sodium chloride, carboxymethylcellulose, titanium dioxide, water and sodium hydroxide at pH of 11. The second fluid component contains a 0.95% solution of sodium hypochlorite. As claimed by the manufacturer, both components react to chloramines as an active substance class (13). Since the primary function of this 2-component agent is to dissolve and clean mostly degenerated soft tissue, as it mainly consists of hypochlorite, the benefit of removing hard calculus in periodontal treatment should be investigated. The purpose of this study was to evaluate the contribution of adjunctive use of a combined hypochlorite and amino acid solution to the effectiveness of SRP under ex vivo conditions. No data regarding similar objectives were available from the literature. Therefore, this study was conducted as a pilot in vitro evaluation. 2 | Int J Dent Hygiene Material and methods Scaling and root planing with hand instruments was carried out on teeth areas occupied by calculus in three different treatment regimens. The findings of this study were assessed in terms of time duration and number of strokes required to complete calculus removal in vitro. Sample preparation and distribution Human teeth extracted for periodontal reasons were stored in 0.1% thymol solution and later assigned to three treatments. The collection of human teeth and their use for study purposes was approved by the Witten/Herdecke University Ethics Committee (No.: 116/2013). All samples showed calculus beneath the cemento-enamel junction occupying varying area sizes. All 60 teeth included met the main criterion: intact and caries-free root surfaces displayed plain root areas affected by calculus. Single as well as multirooted teeth were included. An effort was made to restrict calculus extension either to the root trunk only or to plain areas of single-rooted teeth. Areas affected by furcation involvement, excessive root concavities or convexities were excluded. Each sample was positioned and horizontally embedded in a block of resin (Palapress, Heraeus Kulzer, Germany) to provide fixation during debridement and standardized positioning for photographic analysis. Therefore, the blocks of resin were bi-digitally fixed with the exposed calculus surface on the top to allow for direct access with treating agents and curettes. All samples were consecutively numbered from 1 to 60. All sites of interest were photographed (7000D; Nikon; Tokyo, Japan) under a stereomicroscope (Zeiss 2000; Carl Zeiss; Oberkochen, Germany). The areas covered with calculus were manually determined and measured by calculating the number of pixels (14). To account for equal distribution of areas affected by calculus among three treatment groups, the assignment of the total number of teeth (n = 60) to each group was stratified by the pixel count (Fig. 1). Fig. 1. Labelling the area of interest (yellow line) and its extension upon a plane portion of the root. Becker et al. Effectiveness of calculus preconditioning on SRP Calculus pretreatment and SRP Within the test groups, the 2-component agent (PerisolvTM; RLS Global AB, Sweden) was applied to the area of interest either for 30 s according to the recommendations of the manufacturer (test I) or for 300 s (test II). The agent was removed by rinsing with isotonic saline solution after calculus preconditioning from the surfaces before instrumentation (Fig. 2). No additional treatment to SRP was applied in the control group. Each group was instrumented with a new curette (M23a universal curette, Deppeler, Switzerland); working strokes were performed from apical to coronal parallel to the axis of the tooth. A weight of 500 g was applied during scaling in progress (Fig. 3). The instrument was sharpened after single use (EasySharp Device, Deppeler, Switzerland) (15). The first investigator (MB) selected and preconditioned the specimens. The second blinded investigator (JC) carried out all treatments and recorded the time required for instrumentation (in sec), number of strokes, monitored the weight applied during instrumentation and proved the thoroughness of debridement by tactile detection of remnant calculus on the surfaces. Each sample was instrumented until the area of interest showed no residual calculus in visual and tactile inspection (Detection probe DH2, Deppeler, Switzerland). After root debridement, the surfaces were photographed under microscopic magnification to control the results. Statistical analysis was performed using SPSS 21 (IBM SPSS Statistics Version 21.0; IBM Corp., Armonk, NY, USA). Fig. 3. Scaling and Root planing under constantly controlled contact pressure. Statistical analysis Distribution of intragroup values was tested by Kolmogorow– Smirnow test. Intergroup comparison for instrumentation time and for the number of strokes was evaluated by Kruskal–Wallis test for unevenly distributed values. The level of significance was set at P < 0.05 for all analyses. Results After assignment of teeth to the three treatment groups, equality for tooth type (single and multirooted teeth) was achieved between the test groups I and II (Table 1). The initial calculus extension (expressed by million pixels/ MP) calculated and distributed among all three groups showed no statistically significant differences between groups, thus confirming normal distribution. Median values (quartile 25, quartile 75) were for test group I, test group II and the control group: 1.26 MP (703482/1986458), 1.26 MP (716169/1953752) pixel and 1.27 MP (705951/1804229) Pixel (Fig. 4; Table 2). Table 1. Group characteristics according to selected tooth type Fig. 2. Test sample during Perisolv pretreatment. Group characteristics Single rooted teeth Multi rooted teeth Total number of teeth (n = 60) Test group I (n = 20) Test group II (n = 20) Control group III (n = 20) 44 16 16 12 16 4 4 8 A similar sample selection was achieved in the test groups and more single rooted teeth were included for the control group. Int J Dent Hygiene | 3 Becker et al. Effectiveness of calculus preconditioning on SRP Fig. 4. Initial calculus extension among all three groups showed similar median as well as percentile values (25/75 percentile) for test group I, test group II and the control group: 1.26 MP (703482/1986458), 1.26 MP (716169/1953752) pixel and 1.27 MP (705951/1804229) Pixel. Stroke count Fig. 5. Number of strokes calculus showed similar median values for test group I, test group II and the control group: 18.0, 18.5 and 17.5. The 25th/75th quartile/interquartile range in the test groups were higher compared to the control group: I (14.25/28.5/14.25) II (13/29.25/ 16.25) and III (14.75/24.25/10.5). Median values did not indicate greater differences between test groups I and II and control group: in total 18.0; 18.5 and 17.5 (Fig. 5) strokes were carried out, respectively, per group. Intergroup comparisons showed no statistically significant differences. Instrumentation time The median values for time duration for the test groups I, II and the control groups were 32.0, 33.0 and 46.5 s, respectively (Fig. 6). The intergroup comparison showed no statistically significant differences. Discussion The results of this study do not indicate any triggering effect in achieving thorough debridement of calculus by means of SRP. Neither in terms of SRP duration nor stroke counts required to complete calculus removal were statistically significant differences revealed between all three groups. The distribution of the calculus area extensions within the three treatment groups was equalized due to the stratified distribution. This was confirmed by the intragroup comparison which displayed comparable median values and quartiles (Tab.1). The duration of calculus preconditioning was increased in the second test group in order to evaluate a time-dependent Fig. 6. Median values for time duration for the test groups I, II and the control groups were 32.0, 33.0 and 46.5 s, respectively. The 25th/ 75th quartile/interquartile range (IQR) in the test groups were higher compared to the control group: I (50/24/26), II (52.25/20/32.25) and III (51/32/19). Outliers are indentified with a circle, 1.5 times greater the IQR and with an asterisk, 3 times greater as the IQR. effect upon scaling efficiency. Neither the exposure time recommended by the manufacturer (30 s.) nor a prolonged application (300 s.) had a significant effect on stroke count Table 2. Medians and interquartiles of initial caluclus extension measured by million pixels (MP) in the 3 treatment groups Median (MP) 25/75 quartile Group I: 30 s Group II: 300 s Group III: No Perisolv 1.26 703482/1986458 1.26 716169/1953752 1.27 705951/1804229 A similar calculus extension was observed among the three study groups. 4 | Int J Dent Hygiene Becker et al. Effectiveness of calculus preconditioning on SRP reduction or instrumentation time. The test groups showed a larger deviation for instrumentation time and stroke count when compared to the control groups. Although the teeth were randomized and treated under same study conditions, larger deviations in the test groups were observed. In future investigations, larger numbers of treated teeth might help to avoid these kinds of limitations. Assuming a comparable two-dimensional extension of the calculus in all three groups, standardization in preconditioning was achieved as far as possible. Nevertheless, the thickness of the calculus layer, which may also influence the effectiveness of the scaling by universal curette, was not considered. Therefore, the two-dimensional approach may have limitations regarding equal distribution in terms of calculus volume in the samples. A further limitation of this study is the lack of a control group using different chemical agents (e.g. EDTA or citric acid) which are already well investigated for an improved smear layer removal. Since this investigation was conducted as a pilot study, the primary intention was to evaluate the influence of an alkaline-based solution on SRP efficiency. Kalkwarf and Coworkers stated in the study on gingival curettage that hydrochloride solution had almost no effect on calcified tissues (8). This observation was in agreement with an SEM ex vivo study evaluating the effect of different chemical agents on root surfaces (12). After SRP, root surfaces were exposed to antiformin for 5 min. SEM analysis revealed that antiformin was relatively ineffective in removing the smear layer. However, antiformin followed by citric acid neutralization showed complete debris removal with collagen fibres exposed to the dentinal surface. The authors were able to demonstrate that the sole application of antiformin or hypoclorite solution had no impact on the morphology of calcified tissues such as peritubular dentin. (8, 12). Although no data are available on the influence of hypochlorite or chloramines on calcified deposits, it may be speculated whether hypochlorite solution with demineralizing effect did not raise SRP efficiency. It seems that the characteristics of the mineralized deposits were not altered prior to the instrumentation, which must be regarded as a prerequisite for an improved outcome. Several studies demonstrated the influence of SRP combined with various conditioning agents, such as citric acid, EDTA or tetracycline hydrochlorite on smear layer removal, diameter alteration of dentinal tubules and on the dentin collagen matrix using SEM approach (16, 17). These results indicate that root conditioning after SRP is favourable for smear layer removal as well as in exposing the collagen matrix (18). More recent studies emphasized the positive effect of acidic agents on smear layer removal and on the exposure of dentinal tubules (19, 20). Mittal and coworkers showed that the additional application of tetracycline hydrochloride was superior for smear layer removal and for the enlargement of dentinal tubule diameter when compared to the sole mechanical debridement (21). Nevertheless, studies showing the influence of chemical conditioning on mineralized deposits are rare. A de-epithelizing effect of alkaline agents on the epithelial lining has been demonstrated (7). Therefore, an in vivo application may result in a certain widening of the periodontal pocket. An improved accessibility of periodontal pockets may offer a better instrumentation result in deeper sites when treating patients. The solution also contains chloramines from the hypochlorite and amino acid interaction as an active substance. Chloramines appear to have an influence in the periodontal inflammatory process since they are the end products of polymorphonuclear leucocytes. Assuming a role as an inflammatory mediator, there may be a potential for a host-modulating therapy (22). Clinical studies should be conducted to answer the question whether a beneficial effect in the treatment outcome of periodontal therapy is evident. Clinical relevance Study rationale Applications of hypochlorite-based solutions were associated with positive effects on soft tissue curettage in the past. This study was conducted to affirm a positive effect of PerisolvTM treatment in root debridement under in vitro conditions. Principal findings The data failed to demonstrate an adjuvant effect of PerisolvTM application on SRP procedure carried out by hand instruments in terms of stroke counts and duration. Clinical implications The mechanical traits of calculus did not respond to the chemical pretreatment. However, the reactions within the periodontal pocket in vivo may be different and remain a topic for further investigation. Acknowledgements The material used in the study was provided by Regedent GmbH (Dettelbach, Germany). Beyond the acknowledged support, the authors report speaking engagements for Regedent GmbH (Dettelbach, Germany). No further conflicts of interest were related to this study and the publication of the results. Regedent GmbH and the manufacturer Rubicon Lifescience Global AB, Sweden, had no bearing on how the study was conducted and were excluded from other matters, including analyzing the data and reporting the results. Conflict of interests The author Matthias Becker reports non-financial support from Regedent GmbH, Germany, during the conduct of the study. Anton Friedmann and Kai Fischer report speaking engagements for Regedent GmbH, Germany, outside the submitted Int J Dent Hygiene | 5 Becker et al. 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