Effect of a self-etching adhesive containing an antibacterial monomer on clinical periodontal parameters and subgingival microbiologic composition in orthodontic patients

Comparison of self-etch primers with conventional acid-etch technique for bonding brackets in orthodontics: a systematic review and meta-analysis

BACKGROUND

Bonding with self-etch primers (SEPs) is one of the most popular systems for attaching orthodontic brackets to the enamel surface. There are conflicting reports about the efficacy and success of these systems compared with acid-etch (AE) bonding.

OBJECTIVE

This systematic review and meta-analysis was performed to compare SEP with conventional AE technique for bonding brackets in fixed orthodontics.

SEARCH METHODS

Articles related to the subject of interest were searched in electronic databases, including PubMed, ISI Web of Science, Scopus, EMBASE, and Cochrane's CENTRAL, from inception to 2 June 2021. Search for grey literature, and hand search for relevant studies were also performed.

SELECTION CRITERIA

Based on the PICO model, randomized clinical trials using full-arch bonded fixed orthodontic appliances comparing SEP and conventional AE systems were included in the review process.

DATA COLLECTION AND ANALYSIS

After assessing the risk of bias, data from the included studies were extracted using custom piloted forms. Inverse-variance random-effects meta-analyses were performed to combine the results of bracket failure, adhesive remnant index (ARI), and bonding time.

RESULTS

Nineteen randomized clinical trials were included in the systematic review and 17 randomized clinical trials [5 parallel-group (PG) and 12 split-mouth (SM) studies] were included in the meta-analysis. No significant difference in bracket failure at 6 months [risk ratio (RR) = 1.50, P = 0.26, 12 SM] and (RR = 0.68, P = 0.34, 2 PG), 12 months (RR = 1.6, 8 SM) and (RR = 1.17, P = 0.54, 2 PG), and ≥18 months (RR = 0.84, P = 0.31, 3 SM) and (RR = 1.20, P = 0.3, 3 PG) between SEP and AE groups could be found. Also, ARI score was similar between different bonding systems [mean difference (MD) = -0.44, P = 0.06, 4 SM]. The bonding time per tooth was faster in the SEP group (MD = -26.55, P < 0.001, 2 SM) and (MD = -24.00, P < 0.001, 2 PG).

LIMITATIONS

inclusion of three studies with a high risk of bias and high amount of inconsistency between the results of individual studies were the biggest limitations of our review.

CONCLUSIONS

The bracket bonding failure and ARI score were not significantly different between self-etch and conventional AE bonding systems. The bonding time was lower for the SEP, but some other requirements for SEPs like pumice prophylaxis could diminish this advantage.

REGISTRATION

The protocol for this systematic review was registered at PROSPERO with the ID CRD42021248540.

Application of computational fluid dynamics models for the evaluation of salivary flow patterns and related bacterial accumulation around orthodontic brackets

OBJECTS

To simulate and compare salivary flow patterns over a tooth surface bonded with different orthodontic appliances using computational fluid dynamics (CFD) and investigate the impact of bracket design on salivary flow in relation to peri-bracket bacterial accumulation.

SETTING AND SAMPLE POPULATION

The models were constructed using computed tomography (CT) data of 81 patients scheduled for fixed orthodontic treatment: 27 patients (10 males, 17 females) for the metal Victory MBT™ bracket; 27 patients (seven males, 20 females) for the ceramic Clarity MBT™ bracket; 27 patients (15 males, 12 females) for the Mini Uni-Twin (MUT) bracket.

METHODS

The salivary flow patterns were simulated by CFD and compared between the groups and the model predictions were validated using a bacteriological experiment.

RESULTS

The MUT bracket was associated with the greatest number of low salivary velocity areas, as it is designed with a connector between double tie wings and a right contact angle between tooth surface and bracket base. After archwire placement, the centred slot in the bracket and the bilateral sites around the bracket had higher bacterial retention and needed special oral hygiene measures. The obtuse contact angle of the ceramic bracket formed a pocket structure in the tie-wing area, retarding salivary flow and contributing to bacteria retention.

CONCLUSION

With the evaluation of CFD models, we demonstrate that salivary flow patterns over a tooth surface with a bracket vary with bracket designs and further promote bacterial retention in specific locations, suggesting the need for additional oral hygiene measures for specific bracket types.

In vivo effect of antibacterial and fluoride-releasing adhesives on enamel demineralization around brackets: A micro-CT study

OBJECTIVES

The aim of this in vivo study was to investigate the preventive effect of two different adhesives on enamel demineralization and compare these adhesives with a conventional one.

MATERIALS AND METHODS

Fifteen patients requiring the extraction of their first four premolars for orthodontic treatment were included in the study. One premolar was randomly selected, and an antibacterial monomer-containing and fluoride-releasing adhesive (Clearfil Protect Bond, Kuraray Medical, Okayama, Japan) was used for orthodontic bracket bonding. Another premolar was randomly selected, and a fluoride-releasing and recharging orthodontic adhesive (Opal Seal, Ultradent Products, South Jordan, Utah) was used. One premolar was assigned as a control, and a conventional adhesive (Transbond XT, 3M Unitek, Monrovia, Calif) was used. The teeth were extracted after 8 weeks, and the demineralization areas of the 45 extracted teeth were analyzed using microcomputed tomography with software.

RESULTS

There was no significant difference between the white spot lesion (WSL) rates of the adhesives (P > .05). The volumes of the WSLs varied from 0 to 0.019349 mm³. Although Opal Seal showed the smallest lesion volumes, there was no significant difference in volumetric measurements of the lesions among the groups (P > .05).

CONCLUSIONS

The findings indicated no significant differences between the preventive effects of the adhesives used in this in vivo study over 8 weeks.

Shear Bond Strength of Orthodontic Brackets Fixed with Remineralizing Adhesive Systems after Simulating One Year of Orthodontic Treatment

The objective of this study is to assess, in vitro, the shear bond strength of orthodontic brackets fixed with remineralizing adhesive systems submitted to thermomechanical cycling, simulating one year of orthodontic treatment. Sixty-four bovine incisor teeth were randomly divided into 4 experimental groups (n = 16): XT: Transbond XT, QC: Quick Cure, OL: Ortholite Color, and SEP: Transbond Plus Self-Etching Primer. The samples were submitted to thermomechanical cycling simulating one year of orthodontic treatment. Shear bond strength tests were carried out using a universal testing machine with a load cell of 50 KgF at 0.5 mm/minute. The samples were examined with a stereomicroscope and a scanning electron microscope (SEM) in order to analyze enamel surface and Adhesive Remnant Index (ARI). Kruskal-Wallis and Mann-Whitney (with Bonferroni correction) tests showed a significant difference between the studied groups (p < 0.05). Groups XT, QC, and SEP presented the highest values of adhesive resistance and no statistical differences were found between them. The highest frequency of failures between enamel and adhesive was observed in groups XT, QC, and OL. Quick Cure (QC) remineralizing adhesive system presented average adhesive resistance values similar to conventional (XT) and self-etching (SEP) adhesives, while remineralizing system (OL) provided the lowest values of adhesive resistance.

Effects of self-ligating and conventional brackets on halitosis and periodontal conditions

OBJECTIVE

To evaluate the effects of fixed orthodontic treatment with steel-ligated conventional brackets and self-ligating brackets on halitosis and periodontal health.

MATERIALS AND METHODS

Sixty patients, at the permanent dentition stage aged 12 to 18 years, who had Angle Class I malocclusion with mild-to-moderate crowding were randomly selected. Inclusion criteria were nonsmokers, without systematic disease, and no use of antibiotics and oral mouth rinses during the 2-month period before the study. The patients were subdivided into three groups randomly: the group treated with conventional brackets (group 1, n  =  20) ligated with steel ligature wires, the group treated with self-ligating brackets (group 2, n  =  20), and the control group (group 3, n  =  20). The periodontal records were obtained 1 week before bonding (T1), immediately before bonding (T2), 1 week after bonding (T3), 4 weeks after bonding (T4), and 8 weeks after bonding (T5). Measurements of the control group were repeated within the same periods. The volatile sulfur components determining halitosis were measured with the Halimeter at T2, T3, T4, and T5. A two-way repeated measures of analysis of variance (ANOVA) was used to compare the groups statistically.

RESULTS

No statistically significant group × time interactions were found for plaque index, gingival index, pocket depth, bleeding on probing, and halitosis, which means three independent groups change like each other by time. The risk of tongue coating index (TCI) being 2 was 10.2 times higher at T1 than at T5 (P < .001). Therefore, the probability of higher TCI was decreased by time in all groups.

CONCLUSIONS

The self-ligating brackets do not have an advantage over conventional brackets with respect to periodontal status and halitosis.

Effect of the bracket types on microbial colonization and periodontal status

OBJECTIVE

To evaluate the effect of different bracket types on the levels of Streptococcus mutans (SM) and Lactobacillus (LB) in saliva, in plaque, and on the periodontal condition.

MATERIALS AND METHODS

Forty patients aged 14 to 16 years, who had Angle Class I malocclusion with minimal crowding, were nonsmokers, were without systematic disease, and did not use antibiotics or oral mouth rinses during the 3-month period before the study were randomly selected. The patients were subdivided into two groups with random allocation of bracket type: conventional brackets (CB; Avex Mx, OPAL orth.) with steel wire ligature or self-ligating brackets (SLB; F1000, Leone S.p.A.). Microbial and periodontal records were obtained before bonding (T1) and 1 month after bonding (T2). Microbial samples were collected from the stimulated saliva and the plaque from the labial surfaces of the upper and lower lateral incisors. To estimate the number of colony-forming units of SM and LB, Dentocult SM and LB kits were used. The plaque index (PI), gingival index (GI), and pocket depth (PD) values were recorded to evaluate the periodontal condition. Paired t-test and Mann-Whitney U-test were used to compare the groups statistically.

RESULTS

No significant differences occurred in SM or LB colonization between the groups. In the SLB group, PI, GI, and PD values increased significantly (P < .05). A greater increase was found in PD value in the SLB group (0.98 mm) compared with the CB group (0.04 mm; P < .05).

CONCLUSIONS

The F1000 SLB do not have an advantage over Avex Mx CB with respect to periodontal status and colonization of SM and LB.

Enamel etching for bonding fixed orthodontic braces

BACKGROUND

Acid etching of tooth surfaces to promote the bonding of orthodontic attachments to the enamel has been a routine procedure in orthodontic treatment since the 1960s. Various types of orthodontic etchants and etching techniques have been introduced in the past five decades. Although a large amount of information on this topic has been published, there is a significant lack of consensus regarding the clinical effects of different dental etchants and etching techniques.

OBJECTIVES

To compare the effects of different dental etchants and different etching techniques for the bonding of fixed orthodontic appliances.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 8 March 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 2), MEDLINE via OVID (to 8 March 2013), EMBASE via OVID (to 8 March 2013), Chinese Biomedical Literature Database (to 12 March 2011), the WHO International Clinical Trials Registry Platform (to 8 March 2013) and the National Institutes of Health Clinical Trials Registry (to 8 March 2013). A handsearching group updated the handsearching of journals, carried out as part of the Cochrane Worldwide Handsearching Programme, to the most current issue. There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing different etching materials, or different etching techniques using the same etchants, for the bonding of fixed orthodontic brackets to incisors, canines and premolars in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed the risk of bias of included studies independently and in duplicate. We resolved disagreements by discussion among the review team. We contacted the corresponding authors of the included studies to obtain additional information, if necessary.

MAIN RESULTS

We included 13 studies randomizing 417 participants with 7184 teeth/brackets. We assessed two studies (15%) as being at low risk of bias, 10 studies (77%) as being at high risk of bias and one study (8%) as being at unclear risk of bias. Self etching primers (SEPs) versus conventional etchantsEleven studies compared the effects of SEPs with conventional etchants. Only five of these studies (three of split-mouth design and two of parallel design) reported data at the participant level, with the remaining studies reporting at the tooth level, thus ignoring clustering/the paired nature of the data. A meta-analysis of these five studies, with follow-up ranging from 5 to 37 months, provided low-quality evidence that was insufficient to determine whether or not there is a difference in bond failure rate between SEPs and convention etchants (risk ratio 1.14; 95% confidence interval (CI) 0.75 to 1.73; 221 participants). The uncertainty in the CI includes both no effect and appreciable benefit and harm. Subgroup analysis did not show a difference between split-mouth and parallel studies.There were no data available to allow assessment of the outcomes: decalcification, participant satisfaction and cost-effectiveness. One study reported decalcification, but only at the tooth level. SEPs versus SEPsTwo studies compared two different SEPs. Both studies reported bond failure rate, with one of the studies also reporting decalcification. However, as both studies reported outcomes only at the tooth level, there were no data available to evaluate the superiority of any of the SEPs over the others investigated with regards to any of the outcomes of this review.We did not find any eligible studies evaluating different etching materials (e.g. phosphoric acid, polyacrylic acid, maleic acid), concentrations or etching times.

AUTHORS' CONCLUSIONS

We found low-quality evidence that was insufficient to conclude whether or not there is a difference in bond failure rate between SEPs and conventional etching systems when bonding fixed orthodontic appliances over a 5- to 37-month follow-up. Insufficient data were also available to allow any conclusions to be formed regarding the superiority of SEPs or conventional etching for the outcomes: decalcification, participant satisfaction and cost-effectiveness, or regarding the superiority of different etching materials, concentrations or etching times, or of any one SEP over another. Further well-designed RCTs on this topic are needed to provide more evidence in order to answer these clinical questions.