clinical and microbiological parameters in patients with self-ligating and conventional brackets...

Original Article

Clinical and microbiological parameters in patients with self-ligating and

conventional brackets during early phase of orthodontic treatment

Slavica Pejdaa; Marina Lapter Vargab; Sandra Anic Milosevicc; Senka Mestrovicb; Martina Slajc;Dario Repica; Andrija Bosnjakd

ABSTRACTObjective: To determine the effect of different bracket designs (conventional brackets and self-ligating brackets) on periodontal clinical parameters and periodontal pathogens in subgingivalplaque.Material and Methods: The following inclusion criteria were used: requirement of orthodontictreatment plan starting with alignment and leveling, good general health, healthy periodontium, noantibiotic therapy in the previous 6 months before the beginning of the study, and no smoking. Thestudy sample totaled 38 patients (13 male, 25 female; mean age, 14.6 6 2.0 years). Patients weredivided into two groups with random distribution of brackets. Recording of clinical parameters wasdone before the placement of the orthodontic appliance (T0) and at 6 weeks (T1), 12 weeks (T2),and 18 weeks (T3) after full bonding of orthodontic appliances. Periodontal pathogens ofsubgingival microflora were detected at T3 using a commercially available polymerase chainreaction test (micro-Dent test) that contains probes for Aggregatibacter actinomycetemcomitans,Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola.Results: There was a statistically significant higher prevalence of A actinomycetemcomitans inpatients with conventional brackets than in patients with self-ligating brackets, but there was nostatistically significant difference for other putative periodontal pathogens. The two different typesof brackets did not show statistically significant differences in periodontal clinical parameters.Conclusion: Bracket design does not seem to have a strong influence on periodontal clinicalparameters and periodontal pathogens in subgingival plaque. The correlation between someperiodontal pathogens and clinical periodontal parameters was weak. (Angle Orthod.2013;83:133–139.)

KEY WORDS: Self-ligating brackets; Periodontal pathogens

INTRODUCTION

It has been shown that a fixed orthodontic applianceincreases the number of retentive sites for plaqueaccumulation and impedes oral hygiene.1 Apart from

the increase in the amount of plaque, studies havereported qualitative changes of bacterial plaque—called the qualitative bacterial shift. Qualitative changein the microbiota is characterized by the growth ofputative periodontal pathogens, which are crucial forthe initiation of inflammatory lesions with the interac-tion between the bacteria and the host as a crucialmoment for its progression.2,3 It is now believed thatthe progression of periodontitis is caused by severalbacterial species, such as Aggregatibacter actinomy-cetemcomitans (AA), Porphyromonas gingivalis (PG),Prevotella intermedia (PI), Tannerella forsythia (TF),and Treponema denticola (TD), that accumulate in thesubgingival periodontal biofilm/plaque.4 Recently,there has been a strong emphasis on the polymerasechain reaction (PCR) method for identifying periodon-tal pathogens because of its higher sensitivity andspecificity compared with such conventional proce-dures as microaerophilic and capnophilic cultivation.

a Resident, School of Medicine, University of Split, Split,Croatia.

b Professor, Department of Orthodontics, School of DentalMedicine, University of Zagreb, Zagreb, Croatia.

c Assistant Professor, Department of Orthodontics, School ofDental Medicine, University of Zagreb, Zagreb, Croatia.

d Professor, School of Medicine, University of Split, Soltanska2, 21 000 Split, Croatia.

Corresponding author: Slavica Pejda, University of Split,School of Medicine, Soltanska 2, 21 000 Split, Croatia(e-mail: [email protected]).

Accepted: April 2012. Submitted: January 2012.Published Online: July 3, 2012G 2013 by The EH Angle Education and Research Foundation,Inc.

DOI: 10.2319/010412-8.1 133 Angle Orthodontist, Vol 83, No 1, 2013

Numerous studies indicate acceptable reproducibilityof a commercial multiplex PCR-based test (micro-DentKit, Hain Lifescience GmbH, Nehren, Germany) for thedetection and semi-quantification of subgingival peri-odontal pathogenic species.5,6

Clinically, side effects of fixed orthodontic treatment,such as the qualitative bacterial shift, are manifestedas plaque–associated gingivitis, an increase in pocketprobe depth (PPD), and bleeding on probing.7

Most studies report the reversible nature of thesechanges that occur during orthodontic treatment.8

Some authors, however, have reported the irreversiblenature of periodontal changes during orthodontictreatment, such as a significant loss of periodontalattachment.9

To decrease the side effects of conventionalbrackets, manufacturers introduced self-ligating brack-ets (SLBs), which have gained much popularity duringthe past few years. Some of the proposed favorableclaims of SLBs are (1) the possibility of better oralhygiene because of the reduced complexity of thebracket, which has fewer retentive sites for microbialcolonization; and (2) elimination of elastomeric orstainless steel ligature.3

The clinical superiority of SLBs has been proposedby manufacturers, but the literature lacks evidenceregarding how SLBs affect periodontal status andperiodontal pathogens in subgingival plaque.

The aim of this study was to determine the effect ofbracket type (SLBs or conventional) on the clinicalperiodontal parameters. A further aim was to describethe distribution of various levels of five putativeperiodontal pathogens (AA, PI, PG, TF, TD) using acommercial multiplex PCR-based test in subgingivalplaque samples during the early phase of fixedorthodontic therapy and possible difference in compo-sition of subgingival plaque among patients withdifferent types of brackets.

MATERIALS AND METHODS

Thirty-eight patients (13 male, 25 female), agedbetween 11 and 18 years, participated in this study atthe Department of Orthodontics, School of DentalMedicine, University of Zagreb, Zagreb, Croatia.Patients were divided into two groups with randomdistribution of brackets. One group consisted of 19subjects (7 male and 12 female; mean age, 14.4 6

1.9 years) with SLBs (Damon 3MX, Ormco Corpora-tion, Glendora, Calif), and the control group consistedof 19 subject (6 male and 13 female; mean age, 14.8 6

2.1 years) with conventional brackets (Sprint Brackets,Roth System-Slot 0.018, Forestadent), ligated withstainless steel ligatures (Preformed ligature, D-75106,Forestadent, St. Louis, MO).

According to Pandis et al.,3 the sample size of 16patients per group at a 5 0.05 yields a statistical powerclose to 0.8 for this kind of study. All subjects fulfilledthe following criteria for participation: (1) an orthodontictreatment plan starting with alignment and leveling as afirst stage in both arches, (2) good general health, (3) ahealthy periodontium with no pockets $ 3 mm, (4) noantibiotic therapy in the previous 6 months before thebeginning of the study, and (5) nonsmoker. A writteninformed consent was obtained from the patient andhis or her parents before the study commenced. Theprotocol was reviewed and approved by the EthicalCommittee of the School of Dental Medicine, Univer-sity of Zagreb.

Three weeks before the start of the treatment, allsubjects received oral hygiene instructions consideringthe correct use of toothbrush and interdental brushes;the use of chlorhexidine-containing mouthwashes wasnot allowed during the study. Professional cleaningwas not performed in order to maintain intact subgin-gival microflora. Further reinforcement of oral hygienewas performed during regular checkups. Clinicalparameters were recorded before the placement ofthe orthodontic appliance (T0) and at 6 (T1), 12 (T2),and 18 weeks (T3) of therapy. All time points includedthe measurement of all clinical parameters. Periodon-tal status was determined by measuring PPD at themesial and distal aspects of each tooth using acalibrated periodontal probe (PCP UNC 15 Hu-Friedy,Rotterdam, The Netherlands). To assess the level oforal hygiene and gingival inflammation, full mouthplaque score (FMPS) and full mouth bleeding score(FMBS) were used. The presence of supragingivalplaque and gingival bleeding was assessed by visualcriteria on the labial surfaces adjacent to the gingivalmargin of the teeth and recorded in a dichotomousmanner (presence or absence of plaque and bleeding).The FMPS was recorded first, and FMBS wasrecorded after gentle probing of the sulcus on thesurface of all present teeth.

Subgingival plaque samples were obtained at18 weeks (T3) of therapy. To minimize the contamina-tion, first the value of FMPS was determined, followedby collection of subgingival plaque samples andmeasurement of FMBS and PPD. All clinical measure-ments and both sample collections were performed byone calibrated and experienced investigator.

Before collecting subgingival samples, all sites wereisolated with cotton rolls and were air dried. Aftersupragingival plaque was removed with a probe,subgingival plaque was collected with a sterile paperpoint for 90 seconds and immediately transferred fromthe periodontal sulcus into a transporting box from theproximal sites. The material for microbiological exam-ination was obtained from the subgingival sulcus of the

134 PEJDA, VARGA, MILOSEVIC, MESTROVIC, SLAJ, REPIC, BOSNJAK

Angle Orthodontist, Vol 83, No 1, 2013

following (index) teeth: upper right first molar, upperleft central incisor, upper left first premolar, lower leftfirst molar, lower right central incisor, and lower left firstpremolar. The samples were pooled and sent to alaboratory (Virogena Plus, Zagreb, Croatia) that usedthe micro-Dent test (Hain Lifescience GmbH, Nehren,Germany) for an analysis that was performed blindly.

Once the bacterial DNA was isolated, PCR wasperformed for five putative periodontal pathogens: AA,PG, PI, TF, and TD. Individual pathogens were markedas follows: (1) 0 (undetected – total number of bacterialess than 103); (2) + (slightly positive – total number ofbacteria between 103 and 104), (3) ++ (positive – totalnumber of bacteria between 104 and 105); or (4) +++(strongly positive – total number of bacteria more than105), according to the results of the micro-Dent test.

A t-test was used to compare the difference in thevalues of FMPS, FMBS, and PPD between differenttypes of brackets at each reading. To test the effect oftime reading and the type of brackets used for theseparameters, the mixed analysis of variance with Sidakpost hoc test was used. The Fisher’s exact test and x2

test were used to compare the frequency of occur-rence of bacteria between different types of brackets.The odds ratio was calculated with 95% confidenceinterval to quantify the relationship between the type ofbrackets and the occurrence of bacteria. Power effectsin individual trials were quantified using g2 and Q2.Comparison of the differences between the types ofbrackets and the number of bacteria estimated by PCRand quantified on a scale from 0 to 3 was performedusing the Mann-Whitney test. All analyses were made

using dedicated statistical software SPSS 10.0 (SPSS,Chicago, Ill) at a significance level of P , .05.

RESULTS

The FMPS was estimated by visual criteria, andpercentages of tooth surfaces with or without plaquewere statistically analyzed. Mean value changes ofFMPS showed variability, but it was not statisticallysignificant during different time points of orthodontictreatment, and there were no significant differencesamong SLBs and conventional brackets (Figure 1).Changes of FMBS during time were statistically signif-icant (P 5 .031) with 7.9% variability. There was astatistically significant difference between T0 and T3 (P5 .05), which was not influenced by the type of brackets.

Values of PPD in this study were not statisticallysignificant, and there was no statistically significantdifference in PPD values among patients with differenttypes of brackets. Mean values of PPD were in therange between 0.84 and 2.96. In patients with SLBs,mean values of PPD ranged from 1.36 to 2.96, and inpatients with conventional brackets, mean values ofPPD were between 0.84 and 2.96.

Table 1 shows the frequency with which AA wasdetected. We found statistically significant higherprevalence of AA in patients with conventionalbrackets (median, 2; interquartile range, 1–3) than inpatients with SLBs (median, 0; interquartile range 0–1;P , .001). The average number of detected units ofAA in patients with conventional brackets was 104–105,whereas in patients with SLBs it was ,103. In terms of

Figure 1. Comparison of trend changes of FMPS between different bracket types (arithmetic means with 95% confidence intervals) (fmps0 –

FMPS at baseline; fmps1 – FMPS at 6 weeks; fmps2 – FMPS at 12 weeks; fmps3 – FMPS at 18 weeks).

SUBGINGIVAL FLORA IN ORTHODONTIC PATIENTS 135


their prevalence, the so-called red-complex bacteria(PG, PI, TF, and TD) were not found to be statisticallysignificant among patients with different types ofbrackets. Figure 2 shows a comparison of the occur-rence of red-complex bacteria between different typesof brackets. There was no difference among occur-rence of red-complex bacteria in patients with differenttypes of brackets.

Figure 3 shows the occurrence of combinations ofthe individual pathogens. The total count of testedspecies was lower in patients with SLBs (2.1 6 1.2)than in patients with conventional brackets, mainlybecause of the higher prevalence of AA in patients withconventional brackets.

Our results indicate a statistically significant occur-ence of AA and PG in patients with conventionalbrackets (Figure 4). There was no statistically signif-icant correlation between FMPS, FMBS, and PPD andthe prevalence of the five periodontal pathogens inboth groups of patients (data not shown).

DISCUSSION

Fixed orthodontic appliances impede oral hygienemeasures and increase the formation of dental biofilm,

which causes and initiates inflammatory periodontaldisease, especially in adult patients undergoing ortho-dontic treatment. Preventive measures that wouldcontrol dental biofilm formation during orthodontictreatment can be beneficial, but some biofilm-relatedproblems, such as enamel demineralization andinflammation of soft tissues, remain unsolved.10 Mar-keting materials advertise SLBs as brackets with betterefficacy in controlling bacterial accumulation on theirsurface because of the elimination of elastomeric andstainless steel ligatures. Studies that compare influ-ence of SLBs and conventional brackets on periodon-tal health use elastomeric ligature as ligation method,although it has been shown that elastomeric ligaturesrepresent a bio-hostile material.11–14 Stainless steelligatures are time consuming and are rarely used inclinical practice, but they were used here to eliminatethe method and material of ligation as an additionalfactor of influence on clinical parameters.

The difference among plaque values betweenpatients with different types of brackets was insignif-icant. During 18 weeks of orthodontic treatment therewas no change in PPD values among patients in bothgroups, although high values of FMPS and FMBS onbaseline and during the testing period indicatedgingival inflammation.

In addition to quantitative changes of dental biofilmafter insertion of fixed orthodontic appliances, Leeet al.15 reported significant differences in the prevalenceof putative periodontal pathogens in subgingival plaquein patients with conventional brackets. The goal of thisstudy was to assess the amount of putative periodontalpathogens in the subgingival plaque among patientswith two types of brackets, conventional and SLBs.

Microbiological analysis in the present study found a23.8 times greater chance for the presence of AA in

Table 1. Distribution of AA Among Different Types of Brackets

Bracket Type

TotalSLB Conventional

AA 0 N 14 2 16

% 73.7 10.5 42.1

1 N 3 5 8

% 15.8 26.3 21.1

2 N 2 7 9

% 10.5 36.8 23.7

3 N 5 5

% 26.3 13.2

Figure 2. Occurrence of red complex bacteria (TF, PG, PI) among patients with different types of brackets.



the subgingival plaque of patients with conventionalbrackets than in patients with SLBs. Paolantonio et al.16

reported a higher prevalence of AA upon fixedorthodontic appliance placement. However, their 3-yearstudy found that higher colonization of AA in subgingivalplaque of orthodontic patients does not represent a riskfactor for localized aggressive periodontitis.17

Higher prevalence of AA in the subgingival plaque ofpatients with conventional brackets can be attributed toseveral factors: patient innate flora, inadequate oralhygiene, subgingival placement of orthodontic bands,or surface roughness of stainless steel ligature.

The limiting factor of this study was the cross-sectional manner of collecting subgingival plaque, andAA can be detected in the normal flora of many people.4

There is a need for detailed analysis to select patientswith additional risk factors for periodontal disease and/or possibly genetic factors that may contribute to thedevelopment of aggressive periodontal disease.

Even though the results indicate a higher prevalenceof AA in the subgingival plaque of patients withconventional brackets, there was no causal relationshipbetween clinical periodontal parameters (FMPS, FMBS,PPD) and AA. These findings are in accordance with

Figure 3. Comparison of the absolute number of identified pathogens among patients with different types of brackets.

Figure 4. Comparison of detection frequency of AA and PG (pooled) between SLBs and conventional brackets.



results from Shiloah et al.18 and Bonta et al.,19 whoestablished a weak correlation of AA with bacterialplaque and bleeding on probing. Paolantonio et al.17

attributed this weak correlation of AA and periodontalclinical parameters to overgrowth of other species thatoverwhelm the virulent potential of AA.

Contrary to our results, Garcez et al.20 showed asignificant difference in the amount and composition ofbiofilm close to different types of brackets. Theyshowed that there was less supragingival biofilm onconventional brackets ligated with stainless steelligature than on SLBs in in vitro conditions. On thecontrary, the results from an in vivo study by Pellegriniet al.13 suggest a higher retention of plaque bacteria onconventional brackets ligated with elastomeric ligaturethan on SLBs. A recent study from Pithon et al.21

showed greater bacterial accumulation on SLBs thanon conventional brackets ligated with elastic ligature.Such contradictory results can be attributed to differ-ences in study design, material and methods, studiedmicrobes, and statistical analysis.

It is interesting that in patients with conventionalbrackets, a higher concentration of AA is supported bya higher concentration of PG, and a higher concen-tration of TD with a higher concentration of TF.Cernochova et al.22 also reported coincidence of AAand PG in 9.37% of orthodontic patients, andsimultaneous occurrence of PG, TD, and TF in15.6% of orthodontic patients with gingivitis, whereasour results suggest simultaneous occurrence of PG,TD, and TF in 11% of patients with SLBs and in 18% ofpatients with conventional brackets.

Also, we must stress that Cernochova et al.22

included patients with clinically visible gingivitis,whereas in our study gingivitis was scarce. This factonly proves that mere presence of periodontal patho-gens is not crucial for attachment loss.

Considering characteristic and well-known limitations ofcross-sectional studies supported with findings from otherstudies, we can question the clinical impact of a higherprevalence of AA in the subgingival plaque of patients withconventional brackets. There was no clinically significantdifference in periodontal clinical parameters (FMPS,FMBS, PPD) between patients with SLBs and conven-tional brackets. Our results suggest that there are some,albeit minor, differences in subgingival plaque microflora,mainly because of the higher prevalence of AA in patientswith conventional brackets.

CONCLUSIONS

N There is no difference in plaque aggregation be-tween SLBs and conventional brackets.

N The higher prevalence of AA in patients withconventional brackets is not supported by the

increase of clinical periodontal parameters. Themicrobiological shift that occurs during the first18 weeks of orthodontic therapy does not present arisk for periodontal disease.

N Bracket design does not have a strong influence onperiodontal clinical parameters and periodontalpathogens in subgingival plaque.

ACKNOWLEDGMENTS

This work was supported by Adris foundation. The authorsexpress their gratitude and thanks to Assistant ProfessorStjepan Spalj for his help with the statistical analysis.

REFERENCES

1. Turkkahraman H, Sayin MO, Bozkurt FY, Yetkin Z, Kaya S,Onal S. Archwire ligation techniques, microbial colonization,and periodontal status in orthodontically treated patients.Angle Orthod. 2005;75:231–236.

2. Naranjo AA, Trivino ML, Jaramillo A, Betancourth M, BoteroJE. Changes in the subgingival microbiota and periodontalparameters before and 3 months after bracket placement.Am J Orthod Dentofacial Orthoped. 2006;130:275, e17–e22.

3. Pandis N, Papaioannou W, Kontou E, Nakou M, Makou M,Eliades T. Salivary Streptococcus mutans levels in patientswith conventional and self-ligating brackets. Eur J Orthod.2010;32:94–99.

4. Mayanagi G, Sato T, Shimauchi H, Takahashi N. Detectionfrequency of periodontitis-associated bacteria by polymer-ase chain reaction in subgingival and supragingival plaqueof periodontitis and healthy subjects. Oral Microbiol Im-munol. 2004;19:379–385.

5. Choi DS, Cha BK, Jost-Brinkmann PG, Lee SY, Chang BS,Jang I, Song JS. Microbiological changes in subgingivalplaque after removal of fixed orthodontic appliances. AngleOrthod. 2009;79:1149–1154.

6. Eick S, Pfister W. Comparison of microbial cultivation anda commercial PCR based method for detection of period-ontopathogenic species in subgingival plaque samples.J Clin Periodontol. 2002;29:638–644.

7. Demling A, Demling C, Schwestka-Polly R, Stiesch M,Heuer W. Influence of lingual orthodontic therapy onmicrobial parameters and periodontal status in adults.Eur J Orthod. 2009;31:638–642.

8. Trossello VK, Gianelly AA. Orthodontic treatment andperiodontal status. J Periodontol. 1979;50:665–671.

9. Zachrisson BU, Alnaes L. Periodontal condition in ortho-dontically treated and untreated individuals. I. Loss ofattachment, gingival pocket depth and clinical crown height.Angle Orthod. 1973;43:402–411.

10. Øgaard B. White spot lesions during orthodontic treatment:mechanisms and fluoride preventive aspects. Semin Orthod.2008;14:183–193.

11. Forsberg CM, Brattstrom V, Malmberg E, Nord CE. Ligaturewires and elastomeric rings: two methods of ligation, andtheir association with microbial colonization of Streptococ-cus mutans and lactobacilli. Eur J Orthod. 1991;13:416–420.

12. Gameiro GH, Nouer DF, Cenci MS, Cury JA. Enameldemineralization with two forms of archwire ligation inves-tigated using an in situ caries model—a pilot study.Eur J Orthod. 2009;31:542–546.



13. Pellegrini P, Sauerwein R, Finlayson T, McLeod J, CovellDA Jr, Maier T, Machida CA. Plaque retention by self-ligating vs elastomeric orthodontic brackets: quantitativecomparison of oral bacteria and detection with adenosinetriphosphate-driven bioluminescence. Am J Orthod Dento-facial Orthoped. 2009;135:426, e1–e9.

14. Alves de Souza R, Borges de Araujo Magnani MB, NouerDF, Oliveira da Silva C, Klein MI, Sallum EA, Goncalves RB.Periodontal and microbiologic evaluation of 2 methods ofarchwire ligation: ligature wires and elastomeric rings.Am J Orthod Dentofacial Orthoped. 2008;134:506–512.

15. Lee SM, Yoo SY, Kim HS, Kim KW, Yoon YJ, Lim SH, ShinHY, Kook JK. Prevalence of putative periodontopathogensin subgingival dental plaques from gingivitis lesions inKorean orthodontic patients. J Microbiol. 2005;43:260–265.

16. Paolantonio M, Festa F, di Placido G, D’Attilio M, Catamo G,Piccolomini R. Site-specific subgingival colonization byActinobacillus actinomycetemcomitans in orthodontic patients.Am J Orthod Dentofacial Orthoped. 1999;115:423–428.

17. Paolantonio M, Pedrazzoli V, di Murro C, di Placido G,Picciani C, Catamo G, De Luca M, Piaccolomini R. Clinicalsignificance of Actinobacillus actinomycetemcomitans inyoung individuals during orthodontic treatment. A 3-yearlongitudinal study. J Clin Periodontol. 1997;24:610–617.

18. Shiloah J, Patters MR, Dean JW III, Bland P, Toledo G.The survival rate of Actinobacillus actinomycetemcomitans,Porphyromonas gingivalis, and Bacteroides forsythusfollowing 4 randomized treatment modalities. J Periodontol.1997;68:720–728.

19. Bonta Y, Zambon JJ, Genco RJ, Neiders ME. Rapididentification of periodontal pathogens in subgingivalplaque: comparison of indirect immunofluorescence mi-croscopy with bacterial culture for detection of Actinobacil-lus actinomycetemcomitans. J Dent Res. 1985;64:793–798.

20. Garcez AS, Suzuki SS, Ribeiro MS, Mada EY, Freitas AZ,Suzuki H. Biofilm retention by 3 methods of ligation onorthodontic brackets: a microbiologic and optical coherencetomography analysis. Am J Orthod Dentofacial Orthoped.2011;140:193–198.

21. Pithon MM, dos Santos RL, Nascimento LE, Osorio Ayre A,Alviano D, Bolognese AM. Do self-ligating brackets favorgreater bacterial aggregation? Braz J Oral Sci. 2011;10:208–212.

22. Cernochova P, Augustin P, Fassman A, Izakovicova-HollaL. Occurrence of periodontal pathogens in patients treatedwith fixed orthodontic appliances. Scr Med (Brno). 2008;81:85–96.



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