Systematic Review
 

By Dr. Valentina Caridi
Corresponding Author Dr. Valentina Caridi
Scienze odontostomatologiche e Maxillo-Facciali Roma , - Italy
Submitting Author Dr. Valentina Caridi
ORTHODONTICS

Surface characteristics, orthodontic materials, mutans streptococci, adhesion

Caridi V. Correlation between surface characteristics of different orthodontic materials and adherence of microorganisms. WebmedCentral ORTHODONTICS 2014;5(1):WMC004498
doi: 10.9754/journal.wmc.2014.004498

This is an open-access article distributed under the terms of the Creative Commons Attribution License(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
No
Submitted on: 06 Jan 2014 10:34:39 AM GMT
Published on: 06 Jan 2014 11:28:19 AM GMT

Abstract


Orthodontic appliances serve as different impact zones and modify microbial adherence and colonization, acting as foreign reserves and possible sources of infection1. In a healthy situation, a dynamic equilibrium exists on these surfaces between the forces of retention and those of removal. However, an increased bacterial accumulation often results in a shift toward disease. Mechanisms favour the retention of dental plaque: adhesion and stagnation2. Through a careful analysis of the scientific literature, we want to analyze a correlation between surface characteristics of different orthodontic materials and adherence of microorganisms in orthodontic patients; we were chosen from "PubMed" several publications about surface characteristics, orthodontic materials, mutans streptococci, adhesion. Many studies of bacterial adhesion to orthodontic materials have been published.  In addition, few studies have explained why oral bacteria differentially adhere to the different orthodontic materials3.

Introduction


In the oral cavity, an open growth system, bacterial adhesion to the non-shedding surfaces is for most bacteria the only way to survive2. Orthodontic appliances serve as different impact zones and modify microbial adherence and colonization, acting as foreign reserves and possible sources of infection. These appliances can be associated to difficulty in cleaning. During treatment, retentive areas are created that favor biofilm accumulation and bacterial growth4. One of the greatest challenges in orthodontics consists in maintaining proper oral hygiene during treatment. Brackets, bands and other accessories further aggravate these conditions by retaining dental plaque, which can lead to gingivitis and enamel demineralization, causing white spots and caries5. This adhesion occurs in 4 phases: the transport of the bacterium to the surface, the initial adhesion with a reversible and irreversible stage, the attachment by specific interactions, and finally the colonization in order to form a biofilm. Different hard surfaces are available in the oral cavity (teeth, filling materials, dental implants, or prostheses), all with different surface characteristics. Rough surfaces will promote plaque formation and maturation, and high-energy surfaces are known to collect more plaque, to bind the plaque more strongly and to select specific bacteria. Although both variables interact with each other, the influence of surface roughness overrules that of the surface free energy2. The placement of orthodontic appliances creates a favorable environment for the accumulation of microorganisms, which cause demineralization or exacerbate the effects of any preexisting caries. The incidence of enamel demineralization after fixed orthodontic appliance can involve up to 50% of the patients6-7. Enamel demineralization is a commonly recognized complication of orthodontic treatment with a fixed orthodontic appliance. The enamel demineralization is caused by organic acids produced mainly by mutans streptococci (MS), which have been shown to be the prime causative organisms of dental caries8. Many orthodontic adhesives are commercially available. Composite and glass ionomer are the two main classes of orthodontic bonding adhesives, Differences in bacterial adhesion to the different orthodontic adhesives may be expected because of their different characteristics and the release of incorporated fluoride. In particular, glass ionomers have demonstrated an inhibitory effect on growth or adhesion of oral bacteria because of their fluoride-releasing properties. However, the effect of glass ionomer adhesive on the adhesion of cariogenic bacteria has not been directly compared with that of composite adhesives9

Methods


We carried out a careful analysis of the scientific literature about a correlation between surface characteristics of different orthodontic materials and adherence of microorganisms in orthodontic patients. We were chosen from "PubMed" several publications about surface characteristics, orthodontic materials, mutans streptococci, adhesion.

Many studies of bacterial adhesion to orthodontic materials have been published. We reported most important studies like Ahn et al’s study about the adhesion of cariogenic streptococci to orthodontic metal brackets in terms of the type of bacterial strains, the incubation time, and saliva coating.

Also Ahn et al reported a study about the amount of cariogenic streptococci adhesion to various orthodontic adhesives and to compare the effect of fluoride release on the adhesion amount regarding the type of bacteria, incubation time, and saliva coating. Orthodontic appliance serves as different loci for biofilm formation10. In a study by Eliades et al.11 stainless steel presented the highest critical surface tension and can be expected to have a higher plaque retaining capacity. Metallic orthodontic brackets have been found to induce specific changes in the oral environment such as reduced levels of PH and affinity of bacteria to a metallic surface because of electrostatic reactions, also it increased plaque accumulation, and elevated S. mutans colonization1. Therefore, it is difficult to make a clear assessment that metal brackets have a lower cariogenic effect on the teeth than plastic or ceramic brackets.

Saloom1 et al. claim that the insertion of orthodontic wire tends to create new surfaces available for plaque formation and therefore to increase the level of microorganisms in the oral cavity. It has long been suggested that orthodontic bands and wires lead to an increased plaque accumulation and elevated levels of streptococci and lactobacilli. In addition, orthodontic patients with fixed appliances frequently present an abundance of S. mutans in plaque compared with untreated orthodontic patients1

Review


Microbiological studies have established that, after placement of a fixed orthodontic appliance, the number of bacteria raises significantly, particularly streptococci and lactobacilli, subjecting the oral environment to an imbalance and enabling the emergence of diseases. Although dental biofilm is composed of numerous species of bacteria, it is believed that S. mutans is involved in the early development of carious lesions12. Saloom1 et al conducted a study to investigate the effect of different types of fixed orthodontic appliances on the growth and adherence of microorganisms in oral flora which are Streptococcus mutans (S. mutans) and Candida albicans. Sixty-four of four different fixed orthodontic appliance-samples were used, divided into four groups of sixteen. Type I: Sapphire brackets- Coated wires, type II: Sapphire brackets- Stainless steel wires, type III: Stainless steel brackets- Coated wires and type IV: Stainless steel brackets- Stainless steel wires. Oral strains of S. mutans and Candida albicans were studied in the present study using biochemical test then microbial suspensions were prepared to do the tests of each microorganism including the antimicrobial effects of different appliance-samples on the growth of microorganisms and their adhesion tests. The results showed significant differences between the different appliances in terms of inhibition zone formation (P< 0.001). The adhesion test, which is classified into low, medium and high, showed the adhesion of S. mutans, is low with type I and II, medium with type III and high with type IV, whereas the adhesion of Candida albicans is medium with both type I and II and high with both type III and IV with high significant differences (P< 0.001)1. Ahn13 et al.’s study about a quantitative analysis of the adhesion of cariogenic streptococci to orthodontic metal brackets indicate that two main factors such as the type of strains and incubation times had significant effects on the adhesion of the cariogenic streptococci, where as the saliva coating did not have a significant influence on the binding affinities. Unstimulated whole saliva (UWS) was collected from a 33-year-old healthy volunteer using a spitting method. Saliva was collected into a chilled centrifuge tube in the icebox and centrifuged at 3500 3 g for five minutes, as described previously14. The resulting supernatants were immediately used for the pellicle formation and bacterial adhesion assays. A difference in the interaction effects was statistically significant only between saliva coating and incubation times. The saliva coating did not significantly influence the adhesion of the cariogenic streptococci. However, the adhesion as a result of the saliva coating was affected significantly by the incubation times. The saliva coating tended to gradually decrease the adhesion by the extended incubation time, compared with the noncoated control13. Another study of Ahn9 et al. talking about quantitative determination of adhesion patterns of cariogenic streptococci to various orthodontic adhesives. Five light-cure orthodontic bonding adhesives were selected, consisting of three non–fluoride-releasing composites, one fluoride-releasing composite, and one resin-modified glass ionomer cement (RMGI). Specimens were prepared with Teflon templates with 3.0-mm wide and 2.0-mm deep holes. The results showed a characteristic adhesion pattern according to the type of bacterial strains used. Streptococcus mutans LM7 showed the highest amount of adhesion, whereas S sobrinus B13 showed the lowest amount of adhesion. The cariogenic streptococci adhered to the glass ionomer significantly more than to the composites, whereas there was no significant difference in the adhesion amount among the four composites. The extended incubation time significantly increased bacterial adhesion. However, saliva coating did not significantly alter adhesion patterns of cariogenic streptococci9. Papaioannou15 et al. examined the difference in the adhesion of Streptococcus mutans to three different types of orthodontic brackets and the effect of the presence of an early salivary pellicle and Streptococcus sanguis on adhesion. Three adhesion experiments were performed using stainless steel, ceramic, and plastic orthodontic brackets. In the first experiment a clinical strain of S mutans adhered to the three different types of brackets. For the second, the brackets were treated with saliva before adhesion of S mutans. Finally, the third experiment concerned saliva coated brackets, but before S mutans, S sanguis bacteria were allowed to adhere. There were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets15.

Discussion


Saloom et al’s study1 show a significant difference in the inhibition zones formed with four types of the appliances used with both S. mutans and Candida albicans, the highest inhibition zone was found with type I, followed by type II then type III and the lowest with type IV, this mean that type I which include no metal in its component can inhibit the bacteria and yeast more than type II which has metal arch wire which in turn inhibit bacteria and yeast more than type III that has metal bracket which inhibit bacteria more than type IV that has metal bracket and arch wire. The differences in the bacterial adhesion amount can be explained by the difference in the surface characteristics of each material, including the surface roughness. Since the monocrystalline sapphire brackets (used in types I and II) had smoother surfaces than metal brackets (used in types III and IV) this could be confirmed by the findings of Lee et al.16 who found smoother surface of sapphire than metal bracket in their study, therefore more bacterial adhesion was seen with type III and the most with type IV and this disagree with the findings of Fournier et al.18, who found that the affinity of microorganism for metal brackets was significantly lower than that for brackets made of plastic or porcelain, others like Papaioannou et al.15, they found that there were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets. In the orthodontic bracket surface exposed to oral environment, initially, on a nanosecond scale, a water monolayer binds to a biomaterial surface by either oxygen or hydrogen bonding. Some water molecules may dissociate to hydroxyl groups, which may form surface hydroxyls. Then, a second water layer binds to the first monolayer. On hydrophilic surfaces, for example, to which water molecules bind strongly, repulsive hydration (longrange) and steric (short-range) forces are generated when two such surfaces come in contact because of the energy required to dehydrate the surfaces; these forces are controlled by the presence of cations or pH. On hydrophobic surfaces on the other hand, the orientation of water molecules towards the surfaces is entropically unfavorable17. Thus, in the event that two such surfaces approach each other, water is ejected into the bulk solution, reducing the total free energy of the system and establishing attractive long-range hydrophobic forces between the two surfaces15. Ahn et al.9  reported a significant difference in the amount of adhesion was observed among the cariogenic streptococci strains. This study showed that fluoride release from the orthodontic adhesive cannot alter the adhesion patterns of cariogenic streptococci. There was no difference in the adhesion amount between fluoride-releasing and non–fluoride-releasing composites. In addition, RMGI increased the adhesion of the cariogenic streptococci significantly more than did the composite adhesives. Although RMGI increased the adhesion of cariogenic streptococci in this study, previous studies reported that glass ionomers are significantly more resistant to demineralization than are non–fluoride-releasing composites. This may be mainly attributed to the effect of sustained fluoride release from glass ionomers9. Ahn et al.’s study13 about a quantitative analysis of the adhesion of cariogenic streptococci to orthodontic metal brackets reported a significant difference in the adhesion was observed among the cariogenic streptococci strains. S. mutans OMZ65 adhered to the bracket surfaces significantly more than the other type of strains irrespective of the incubation time and saliva coating. The orthodontic brackets are covered instantly by the salivary pellicle in the oral cavity. In contrast to the noncoated samples, the amount of adhesion in the saliva-coated samples was largely influenced by the salivary pellicle formed on the underlying materials. The salivary pellicle as a binding receptor can not only promote the adhesion19 but can also prevent the adhesion by decreasing the surface- free energy of the underlying materials20. If a specific receptor is present in the salivary pellicle formed on the underlying material, the amount of adhesion will increase significantly because of saliva coating. This study will provide a primary step in identifying a means to interfere with the process of adhesion of pathogenic bacteria to the pellicle or plaque on the orthodontic appliances13

Conclusion(s)


Analyzed studies show that an extended incubation time increased the level of bacterial adhesion, irrespective of the bacterial strains, whereas the effect of saliva coating did not significantly alter the adhesion trend of cariogenicstreptococci. Also these studies prove that the adhesion pattern of the cariogenic streptococci is different between composite adhesives and RMGI, and the adhesion amount is not strongly influenced by fluoride releasing and saliva coating. No obvious difference was found in the adhesion of S mutans, whether they were alone or in presence of S sanguis, to stainless steel, plastic, and ceramic orthodontic brackets. S sanguis seems to have an antagonistic relationship with S mutans, interfering with its adhesion.

References


1. “The influence of different types of fixed orthodontic appliance on the growth and adherence of microorganisms (in vitro study)”; Hayder F. Saloom, Harraa S. Mohammed-Salih, Shaymaa F. Rasheed; J Clin Exp Dent. 2013;5(1):e36-41
2. “The influence of surface roughness and surface-free energy on supra- and subgingival plaque formation in man: A review of the literature”; M. Quirynen, C. M. L. Bollen; Journal of Clinical Periodontology Volume 22, Issue 1,  pages 1–14, January 1995
3. “Surface Characteristics of Orthodontic Materials and Their Effects on Adhesion of Mutans streptococci”; Seung-Pyo Lee, Shin-Jae Lee, Bum-Soon Lim, and Sug-Joon Ahn; The Angle Orthodontist Volume 79, Issue 2 (March 2009)
4. Lee SJ, Kho HS, Lee SW, Jang WS. “Experimental salivary pellicles on the surface of orthodontic materials”. Am J Orthod DentofacialOrthop. 2001;119:59–66.
5. Derks A, Katsaros C, Frencken JE, van’t Hof MA, Kuijpers- Jagtman AM. “Caries-inhibiting effect of preventive measures during orthodontic treatment with fixed appliances. A systematic review”.Caries Res. 2004;38:413-20.
6. Gorelick L, Geiger AM, Gwinnett AJ. “Incidence of white spot formation after bonding and banding”. Am J Orthod. 1982;81:93–98
7. Artun J, Brobakken B.”Prevalence of caries and white spots after orthodontic treatment with multibonded appliances”.Eur J Orthod. 1986;8:229–234
8. Wisth PJ, Nord A. “Caries experience in orthodontically treated individuals”. Angle Orthod. 1977;47:59–64
9. “Quantitative Determination of Adhesion Patterns of Cariogenic Streptococci to Various Orthodontic Adhesives”; Sug-Joon Ahn; Bum-Soon Lim; Yong-Keun Lee; Dong-Seok Nahm; Angle Orthodontist, Vol 76, No 5, 2006
10. van Gastel J, Quirynen M, Teughels W, Pauwels M, Coucke W,Carels C. “Microbial adhesion on different bracket types in vitro”.Angle Orthod. 2009;79:915-21.8.
11. Eliades T, Eliades G, Brantley WA. “Microbial attachment on orthodontic appliances: I. Wettability and early pellicle formation on bracket materials”. Am J Orthod Dentofacial Orthop. 1995;108:351-60.
12. Petersson LG, Maki Y, Twetman S, Edwardsson S. “Mutans streptococci in saliva and interdental spaces after topical applications of an antibacterial varnish in schoolchildren”. Oral Microbiol Immunol.1991;6:284-7.
13. “Quantitative Analysis of the Adhesion of Cariogenic Streptococci to Orthodontic Metal Brackets”; Sug-Joon Ahn; Bum-Soon Lim; Hyeong-Cheol Yang; Young-Il Chang; Angle Orthodontist, Vol 75, No 4, 2005
14. Ahn SJ, Kho HS, Lee SW, Nahm DS. “Roles of salivary proteins in the adherence of oral streptococci to various orthodontic brackets”. J Dent Res. 2002;82:411–415.
15. “Adhesion of Streptococcus mutans to Different Types of Brackets”; William Papaioannou; Sotiria Gizani; Maria Nassika; Efterpi Kontou; Melachrini Nakou; Angle Orthodontist, Vol 77, No 6, 2007
16. Lee SP, Lee SJ, Lim BS, Ahn SJ. “Surface characteristics of orthodontic materials and their effects on adhesion of mutans streptococci”; Angle Orthod. 2009;79:353-60.
17. Brash JL. “Studies on protein adsorption to blood compatible materials”. In: Missirlis YF, Lemm W, eds. Modern Aspects of Protein Adsorption on Biomaterials. Dordrecht: Kluwer Academic Press; 1991:39–47
18. Fournier A, Payant L, Bouclin R. “Adherence of Streptococcus mutans to orthodontic brackets”. Am J Orthod Dentofacial Orthop.1998;114:414-7
19. Ahn SJ, Kho HS, Lee SW, Nahm DS. “Roles of salivary proteins in the adherence of oral streptococci to various orthodontic brackets”. J Dent Res. 2002;82:411–415.
20. Weerkamp AH, van der Mei HC, Busscher HJ. “The surface free energy of oral streptococci after being coated with saliva and its relation to adhesion in the mouth”. J Dent Res. 1985;64:1204–1210.

Source(s) of Funding


None

Competing Interests


None

Reviews
0 reviews posted so far

Comments
0 comments posted so far

Please use this functionality to flag objectionable, inappropriate, inaccurate, and offensive content to WebmedCentral Team and the authors.

 

Author Comments
0 comments posted so far

 

What is article Popularity?

Article popularity is calculated by considering the scores: age of the article
Popularity = (P - 1) / (T + 2)^1.5
Where
P : points is the sum of individual scores, which includes article Views, Downloads, Reviews, Comments and their weightage

Scores   Weightage
Views Points X 1
Download Points X 2
Comment Points X 5
Review Points X 10
Points= sum(Views Points + Download Points + Comment Points + Review Points)
T : time since submission in hours.
P is subtracted by 1 to negate submitter's vote.
Age factor is (time since submission in hours plus two) to the power of 1.5.factor.

How Article Quality Works?

For each article Authors/Readers, Reviewers and WMC Editors can review/rate the articles. These ratings are used to determine Feedback Scores.

In most cases, article receive ratings in the range of 0 to 10. We calculate average of all the ratings and consider it as article quality.

Quality=Average(Authors/Readers Ratings + Reviewers Ratings + WMC Editor Ratings)