Failure patterns of different bracket systems and their influence on treatment duration: A retrospective cohort study

Orthodontic bracket failure rate after bonding with and without primer - A systematic review and meta-analysis

OBJECTIVE

To compare the difference in failure rates between orthodontic brackets bonded with light-cured primer and those bonded without primer.

MATERIAL AND METHODS

An electronic search of five databases and additional manual searches were performed until January 2024. Randomized and prospective non-randomized controlled trials directly comparing the bracket failure rate with and without primer. Two authors independently collected study characteristics by extracting outcome data from pre-defined sheets. After evaluating the risk of bias, the odds ratio and 95% confidence intervals (CIs) were calculated with random-effects models.

RESULTS

Four studies were evaluated using qualitative and quantitative analysis. The analysis included data from 199 patients (1691 brackets with primer and 1646 brackets without primer). Random effects of pooled meta-analysis demonstrated statistically significant differences in the bracket failure rates (odds ratio=1.50, p=0.010, [95% CI 1.10 to 2.05]). The risk of failure was 1.5 times greater when brackets were bonded without primer.

CONCLUSION

The results should be interpreted in the context of the limited sample size, even though there was a substantial difference in the failure rates of brackets with and without a primer, favouring the use of a primer. Furthermore, the validity of the finding may be limited by potential variables such as patient factors, clinician expertise, and isolation. More extensive research is required to validate these findings (PROSPERO CRD42024593134).

The Influence of Resin Infiltration on the Shear Bond Strength of Orthodontic Brackets: A Systematic Review and Meta-Analysis

The quality of the enamel plays a critical role in the retention and performance of orthodontic brackets. This systematic review and meta-analysis aimed to evaluate the effect of resin infiltration pretreatment on the shear bond strength (SBS) of orthodontic brackets. An electronic search was conducted in October 2024 using PubMed, Web of Science (WoS), and Scopus databases, employing the keywords (resin infiltration AND bracket); (ICON AND bracket). The review adhered to PRISMA guidelines and utilized the PICO framework. Of the 143 articles initially identified, 63 underwent screening. Strict inclusion criteria were applied of which the most important were resin infiltration pretreatment, studies conducted on natural teeth and SBS evaluation. This left 19 studies for final analysis. The risk of bias was assessed using the checklist for quasi-experimental studies (Non-Randomized Experimental Studies) developed by the Joanna Briggs Institute (JBI). Among these, 13 studies used human teeth and 13 utilized Transbond XT as the adhesive. Metal brackets were predominantly examined (n = 17). The Adhesive Remnant Index (ARI) was assessed in 13 studies. Importantly, 11 studies concluded that resin infiltration significantly enhances SBS, 8 of which were conducted on human teeth. The meta-analysis revealed significantly higher SBS results when resin infiltrate was applied to healthy enamel. This finding underscores the dual benefits of resin infiltration: increased bond strength and the protection of enamel integrity during debonding procedures. The results suggest that resin infiltration not only improves the mechanical retention of orthodontic brackets but also serves as an enamel-preserving approach.

Metallic vs Ceramic Bracket Failures After 12 Months of Treatment: A Prospective Clinical Trial

INTRODUCTION

Orthodontic treatment with fixed vestibular appliances is still widely used worldwide. When choosing the aesthetic alternative of ceramic brackets, the possibility of failure and cracking of braces should be considered. Therefore, the aim of the present study was to compare the failure rates of ceramic and metal brackets in a 12-month clinical study.

METHODS

Eighty patients undergoing fixed orthodontic treatment with vestibular appliances were enrolled and divided into 2 equal groups: MET for metal brackets and CER for ceramic brackets. After bonding, bracket failures were recorded for 12 months, along with the archwire placed at the time of failure. Angle's dental class, skeletal class, Wits appraisal, Little's irregularity index, overjet, overbite, age, and gender of the patients were recorded from pretreatment cephalometric tracings and study casts. The data were statistically analysed (P < .05).

RESULTS

Significantly higher failure rates were found for ceramic brackets in the overall analysis, in the mandibular arch, and in the posterior region. Regression analysis revealed a significant influence of round nickel-titanium archwires on higher failure rates, whilst a significant influence of rectangular archwires was found on lower failure rates.

CONCLUSIONS

Ceramic brackets showed higher failure rates. Patients should be aware that orthodontic treatment with ceramic brackets may involve delays and inconvenience due to the higher failure rate compared to metal brackets.

Accuracy of One-Piece vs. Segmented Three-Dimensional Printed Transfer Trays for Indirect Bracket Placement

OBJECTIVE

To assess the accuracy of three-dimensional (3D) printed one-piece vs. multiple segmented transfer trays for indirect bonding techniques in moderate and severe crowding cases.

METHODS

Eighty digital maxillary dental models were produced by an extraoral scanner. 3D-printed one-piece and segmented trays were virtually designed utilizing Maestro 3D Ortho Studio® v4 and printed using a NextDent printer. The sample was classified into two groups: Group 1 (moderate crowding) included 40 digital models with a space deficiency of 6-7 mm, and Group 2 (severe crowding) included 40 digital models with a space deficiency of 10 mm. Ortho classic brackets were then placed into the 3D printed models with the aid of the transfer trays, and the models with the final bracket positioning were scanned using iTero scanner. Four measurements were selected on each tooth to perform the analysis. Mann-Whitney and Kruskal-Wallis tests were used for comparisons. A p-value of ≤ 0.05 was considered statistically significant.

RESULTS

In the moderate crowding group, statistically significant differences were detected between the one-piece, segmented, and control groups for three measurements (p < 0.001), while the rest of the measurements showed no significant differences (p > 0.05). In the severe crowding group, no significant differences were detected for any of the measurements.

CONCLUSIONS

One-piece and segmented 3D-printed transfer trays are considered accurate tools for indirect bonding in moderate and severe malocclusion cases. The severity of crowding did not affect the accuracy of bracket transfer in indirect bonding.

The Mechanical and Clinical Properties of Customized Orthodontic Bracket Systems-A Comprehensive Review

The rise of computer-aided design and computer-aided manufacturing (CAD/CAM) and 3D printing technologies in orthodontics has revolutionized the development of customized labial and lingual bracket systems with a variety of materials, which offer potential advantages over traditional orthodontic brackets. To highlight the current state of knowledge regarding the mechanical and clinical properties of CAD/CAM and 3D-printed custom bracket systems, we conducted a comprehensive search across the PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases to identify relevant articles published before April 2024. Mechanical (including fracture toughness, hardness, modulus of elasticity, frictional resistance, slot accuracy, torque transmission, and shear bond strength) and clinical (including treatment efficiency and duration, cost, and comfort) properties were compared between traditional and customized orthodontic bracket systems in the current review. Our findings suggest that customized brackets have the potential to increase bracket slot precision, reduce treatment time, and offer cost-efficiency. However, it is worth noting that the advantages and disadvantages of customized bracket systems vary depending on the bracket material and the manufacturing methods, warranting comprehensively controlled investigations in the future.

Factors Related to Bracket Bond Failure during Orthodontic Treatment: A Single-Centre Single-Operator Study

This study aimed to investigate the influence of various patient-specific and bracket location-specific factors on bracket survival rates during comprehensive fixed appliance orthodontic treatment. A total of 197 patients (116 females, 81 males; mean age 16.3 years) having completed orthodontic treatment were included in this retrospective cohort study. Patients were treated using stainless steel non-self-ligating brackets, and the treatment duration was 23.7 months on average. The primary outcome was bracket bond failure. Potential predictors for bracket bond failure recorded included age, sex, oral hygiene, treatment duration, and several pre-treatment cephalometric characteristics such as overjet, overbite, and sagittal and vertical skeletal relationships. Factors associated with bracket failure were analysed with Cox regression, and proportional hazard assumptions were assessed using Kaplan-Meier tests. The overall failure rate was 4.4%. Bracket bond failure rates varied among tooth types and seemed to occur more on posterior teeth and on the right side of the arch. Bracket failure was more common in male patients and those with poor oral hygiene. Concerning dentofacial characteristics, bracket failure of anterior teeth was more common in those with an increased overjet and overbite.

Comparison of the Adhesive Remnant Index and Shear Bond Strength of Different Metal Bracket Bases on Artificially Aged Human Teeth: An In vitro Study

Aim

Bond failure can compromise the clinical efficacy and duration of orthodontic treatment. A decemented bracket can lengthen the course of treatment by about 0.6 months. This study aimed to compare the adhesive remnant index (ARI) and shear bond strength of different metal bracket bases on artificially aged human teeth.

Materials and Methods

In this experimental in vitro, prospective, cross-sectional study, thirty-six human premolars were cemented with three types of metal bracket base designs: Group 1 had a laser-structured base, Group 2 had a mesh base, and Group 3 had a base with retention grooves. All groups were bonded with Transbond XT light-curing resin. Shear strength testing was performed, and the ARI was evaluated. The parametric one-factor analysis of variance test and Tukey's post hoc test were used for the comparison of shear bond strength, and the effect size was also evaluated with eta squared. In addition, the Kruskal-Wallis test was used to compare the ARI of the three groups on an ordinal scale. All statistics were set at a significance of P < 0.05.

Results

The ARI scores did not exhibit any statistically significant differences (P = 0.163). Nevertheless, the three groups exhibited statistically significant differences in shear bond strength, with an effect size of 69% (P < 0.001). The mesh base bracket had the lowest average (9.9 ± 2.6 MPa) (P < 0.001), while the laser-structured base bracket had the greatest average (19.1 ± 3.0 MPa) (P = 0.006).

Conclusion

The variation in shear bond strength was influenced by 69% due to the type of the metal bracket base used. Laser-structured and mesh-based brackets had the highest and lowest shear strength, respectively. All bases left a similar ARI on the tooth enamel.

Shear Bond Strength of Metal and Ceramic Brackets Depending on Etching Protocol in Direct Bonding Technique

Successful orthodontic therapy, apart from a proper treatment plan, depends on optimal bracket-enamel adhesion. Among numerous factors affecting adhesion, the type of bracket and preparation of the tooth's surface are crucial. The aim of this study was to compare the shear bond strength (SBS) of metal and ceramic brackets to the enamel's surface using direct bonding. Forty extracted human premolars were divided into four groups according to the etching method (etch-and-rinse and self-etch) and bracket type. The SBS and adhesive remnant index (ARI) were determined. The ceramic brackets achieved the highest SBS values both in the self-etch (SE) and etch-and-rinse (ER) protocols. Higher SBS values for ceramic and metallic brackets were found in the ER protocol. In all tested groups, the achieved SBS value was satisfactory to withstand orthodontic and occlusal forces. There was no significant difference in the ARI score between study groups (p = 0.71). The fracture occurred between the bracket base and adhesive material in both types of brackets, which decreased the risk of enamel damage during debonding.

Impact of polishing system on surface roughness of different ceramic surfaces after various pretreatments and bracket debonding

OBJECTIVE

Evaluating various polishing methods after bracket debonding and excessive attachment material removal for different ceramics and pretreatments.

MATERIAL AND METHODS

Zirconia (ZrO2), leucite (LEU) and lithium disilicate (LiSi) specimens were pretreated with a) silica coated alumina particles (CoJet); LEU and LiSi additionally with b) hydrofluoric acid (HF), c) Monobond Etch&Prime (MEP), d) silicium carbide grinder (SiC) before bracket bonding, shearing off, ARI evaluation, excessive attachment material removal and polishing with i) Sof-Lex Discs (Soflex), ii) polishing paste (Paste), iii) polishing set (Set). Before/after polishing surface roughness (Ra) was measured with a profilometer. Martens hardness parameter were also assessed.

RESULTS

Irrespective of pretreatment Ra of LEU increased the most, followed by LiSi and ZrO2 (p < 0.001, SiC: p = 0.012), in accordance with the measured Martens hardness parameter. CoJet/SiC caused greater roughness as HF/MEP (p < 0.001). The ZrO2 surface was rougher after polishing with Paste/Set (p < 0.001; p = 0.047). Ra improved in the LEU/CoJet, LEU/SiC and LiSi/SiC groups with Soflex/Set (p < 0.001), in the LiSi/CoJet and LEU/HF groups by Soflex (p = 0.003, p < 0.001) and worsened by Paste (p = 0.017, p < 0.001). Polishing of HF or MEP pretreated LiSi with Set increased Ra (p = 0.001, p < 0.001), so did Paste in the LEU/MEP group (p < 0.001).

CONCLUSIONS

Paste couldn't improve the surfaces. Soflex was the only method decreasing Ra on rough surfaces and not causing roughness worsening. Polishing of LEU/LiSi after MEP, LEU after HF pretreatment doesn´t seem to have any benefit.

CLINICAL RELEVANCE

To avoid long-term damage to ceramic restorations, special attention should be paid to the polishing method after orthodontic treatment.

Shear bond strength of adhesive precoated brackets: A comparative in vitro study

OBJECTIVE

This study compared the shear bond strength of orthodontic precoated brackets from different manufacturers.

METHODS

Sixty extracted human premolar teeth were divided into six groups (n=10). The groups were bonded with one of the following brackets: 3M™ Unitek Victory™ Series™ with APC, 3M™ Unitek Clarity™ Advanced Ceramic™ with APC, TP Nu-Edge® NX Cobalt-Chromium and TP In-Vu® ceramic Readi-Base® both with eXact® orthodontic adhesive, 3M™ Unitek Clarity Advanced Ceramic™ and 3M™ Unitek Victory™ Series™ both with Transbond™ XT Adhesive. Each group was tested for shear bond strength using a universal testing machine. Each sample was observed under a dissecting microscope and received an adhesive remnant index (ARI) score. Statistical analysis was performed using Tukey's Standardized Range (HSD) Test to make comparisons among all groups and a Wilcoxon rank-sum test to evaluate for pairwise comparisons between the groups. The P-values<0.05 were considered significant.

RESULTS

The ceramic control was not statistically different from the metal control, 3M™ Victory™ APC™, TP In-Vu® ceramic eXact® or TP Nu-EDGE® eXact® in terms of shear bond strength (7.69±1.41MPa, 7.72±1.25MPa, 8.70±1.93MPa, 4.90±1.76MPa, 5.33±0.78MPa, respectively). However, it was statistically different from 3M™ Ceramic APC™ (10.29±2.78MPa). In terms of modulus, there were no statistical differences. TP's Nu-edge® had the lowest average ARI score, but was not statistically different when compared to the other groups.

CONCLUSION

3M™ Unitek's Ceramic APC had a statistically higher SBS than the non-precoated brackets and TP Orthodontics' precoated brackets. However, all SBS were 4.9 MPA or above, which is deemed clinically acceptable in terms of laboratory forces. There was no statistical difference between manufacturing companies or precoated vs. non-precoated modulus and ARI scores.

Bracket Bond Failures: Incidence and Association with Different Risk Factors-A Retrospective Study

BACKGROUND

Bracket bonding failure is one of the relevant problems in fixed orthodontics therapy, which affects the total treatment and quality of treatment results. The purpose of this retrospective study was to evaluate the frequency of bracket bond failure and find out risk factors.

METHODS

A total of 101 patients with an age range of 11-56 years were included in this retrospective study and treated for a mean period of 30.2 months. Inclusion criteria were: males and females with permanent dentition and completed orthodontic treatment in both fully bonded dental arches. Risk factors were calculated using binary logistic regression analysis.

RESULTS

The overall bracket failure rate was 14.65%. The bracket failure rate was significantly higher in the younger patients' group (p = 0.003). In most cases, patients experienced bracket failures in the first month of the treatment. Most of the bracket bond failures occurred on the left lower first molar (29.1%) and were twice as common in the lower dental arch (66.98%). Patients with increased overbite had an increased likelihood of bracket loss (p = 0.042). Class II malocclusion increased the relative risk of bracket failure, while Class III decreased the rate of bracket failure, but the difference was not statistically significant (p = 0.093).

CONCLUSIONS

The bracket bond failure rate was higher in younger patients than in older patients. Brackets placed on mandibular molars and premolars had the highest failure rate. Class II was associated with an increased bracket failure rate. Increased overbite statistically significantly increases bracket failure rate.

Impact of different pretreatments and attachment materials on shear bond strength of indirectly bonded brackets using CAD/CAM transfer trays to monolithic zirconia

OBJECTIVE

Investigating the impact of different pretreatment methods, attachment materials and aging regimens on shear bond strength (SBS) between zirconia and indirectly bonded brackets using CAD/CAM transfer trays.

METHODS

Zirconia substrates were conditioned with silica coated alumina (CoJet) and a) Clearfil Ceramic Primer Plus (CF), b) RelyX Ceramic Primer (RXP), c) Futurabond U (FU). Brackets were virtually placed, transfer tray designed (OnyxCeph) and 3D-printed for indirect bonding with a) Transbond LV (TBL), b) Nexus NX3 (NX3), c) Maximum Cure (MC). SBS testing was performed with a universal testing machine after 24 h, 500 thermal cycles, 90 d. Directly bonded brackets to human enamel using Transbond XT Adhesive served as control. The adhesive remnant index (ARI) was evaluated. Data was analyzed with Shapiro-Wilk, Kruskal-Wallis and Dunn's post-hoc test with Bonferroni correction, Chi² test (p < 0.05), and the Weibull modulus was calculated.

RESULTS

SBS ranged from 0.1 to 15.5 MPa and were influenced mostly by the attachment material. NX3 generally showed the highest values (9.5-15.8 MPa). Initially RXP/TBL and FU/TBL presented the lowest values (4.3/4.8 MPa). Aging regimens reduced SBS of MC irrespective of pretreatment, after 90 d values ranged from 0.1 to 0.9 MPa. ARI 1 was predominant in all MC groups and FU/NX3, 2 and 3 in the other groups. Weibull moduli ranged between 0.15 (MC/RXP/500 TC) and 6.24 (NX3/RXP/500 TC).

SIGNIFICANCE

MC seems not to be suitable for indirect bonding using CAD/CAM transfer trays to zirconia. NX3 showed similar SBS values compared to the control, TBL lower.

Comparative assessment of dental and basal arch dimensions of passive and active self-ligating versus conventional appliances : A randomized clinical trial

PURPOSE

In this parallel, three-arm, single-center randomized trial, the dental and basal arch dimensions after orthodontic treatment using conventional brackets and passive and active self-ligating (SL) brackets were compared.

METHODS

Patients needing comprehensive orthodontic treatment were randomly allocated to the active SL, passive SL, or conventional brackets (control) group. All patients were treated with a standardized arch wires sequence. Eligibility criteria included class I malocclusion in the permanent dentition, crowding (4-6 mm), and adequate oral hygiene. The primary outcome was intermolar width, based on cone beam computed tomography (CBCT) scans. Secondary outcomes were maxillary and mandibular widths in the canines and premolars regions, dental arch depth, buccolingual inclination, and alignment duration. Blinding of outcome assessment was implemented. Patients were followed every 4 weeks until insertion of the stainless steel 0.019 × 0.025 wire. Mean values were computed from CBCT sections, and data were analyzed using a one-way analysis of variance.

RESULTS

In all, 66 patients (ages 18-25 years) were randomized into a 1:1:1 ratio; 7 patients dropped out before treatment initiation. Examining dental arch dimensions in the canine and premolar regions showed that expansion of the maxillary dental arch was greatest in the passive SL brackets group, less in the active SL brackets group, and lowest in the control group (P < 0.01). Changes in maxillary intermolar width between the three groups were not significant, and changes in basal arch dimensions, depth of dental and basal arches, buccolingual inclination, and alignment duration were similar in the three groups.

CONCLUSIONS

Self-ligating brackets were not more effective than conventional brackets when examining intermolar width, basal transverse dimensions, depth of the arch, and alignment duration.

Impact of different pretreatments and attachment materials on shear bond strength between monolithic zirconia restorations and metal brackets

To investigate the influence of different pretreatment methods, attachment materials and artificial aging on shear bond strength (SBS) between monolithic zirconia and metal brackets. Zirconia substrates were pretreated with silica coated alumina (CoJet) and (1) clearfill ceramic primer plus (CF), (2) RelyX ceramic primer (RXP), (3) Futurabond U (FU). The brackets were bonded with (1) Transbond XT Adhesive (TB), (2) BrackFix Adhesive (BF), (3) bracepaste adhesive (BP). SBS was tested after 24 h, 500 thermal cycles, 90 d at 37 °C with a universal testing machine. SBS values reached from 8.3 to 16.9 MPa. The Weibull moduli ranged between 0.37 (RXP combined with BP after 90 d) and 7.42 (CF combined with TB after 24 h). The pretreatment with FU after 90 d, independent of the attachment material, and RXP with BF resulted in the lowest SBS values 8.3–9.9 MPa, the combination of RXP or CF with TB showed the highest (13.2–16.9 MPa) independent of aging. After FU pretreatment the proportion of ARI 1 and 0 was higher, of ARI 3 lower as after CF and RXP pretreatment. All tested combinations showed sufficiently high SBS values for clinical use. Pretreatment with FU presented the lowest values after 90 days.

Bonding Failures of Lingual Orthodontic Brackets: A Retrospective Study Comparing Lingual Brackets with KommonBase Extensions, to Customized Lingual Brackets

The aim of the present study was to evaluate in a clinical setting the bracket survival of lingual brackets bonded with the KommonBase system, and to compare it to the survival of a customized lingual bracket system. Two convenience samples of 13 consecutive patients treated with lingual fixed appliances with KommonBase extensions (Group 1) and 14 consecutive patients treated with customized Incognito™ lingual fixed appliances were retrospectively enrolled (Group 2). First time debondings were recorded from the files. Data were submitted to statistical analysis and a Log-rank test was used to compare the Kaplan–Meier survival curves between the two groups. Statistical significance was set as p < 0.05. Lingual brackets bonded with the KommonBase system showed a failure rate of 8%, while Incognito brackets showed a failure rate of 7.1%. The Log-rank test comparing the Kaplan–Meier survival curves revealed no statistically significant difference between the two groups (p = 0.343). Most debondings occurred during the first 6 months. Upper incisors and canines were less prone to debond than premolars and molars. In conclusion, no difference in bracket survival was observed between the KommonBase system and a customized lingual appliance.

Effect of Enamel Pretreatment with Pastes Presenting Different Relative Dentin Abrasivity (RDA) Values on Orthodontic Bracket Bonding Efficacy of Microfilled Composite Resin: In Vitro Investigation and Randomized Clinical Trial

Bonding failure is a clinical issue frequently encountered in orthodontic practice. The aim of this study was to evaluate enamel pretreatment both in vitro and clinically using agents with different RDA values before brackets' bonding, to assess if RDA can affect the Shear Bond Strength (SBS), Adhesive Remnant Index (ARI) and clinical failure rate of orthodontic brackets. For the in vitro study, 220 bovine teeth were pretreated with agents with different RDA values. Subsequently, brackets were bonded. For the clinical study, 20 patients underwent bonding of 20 brackets each with a split-mouth design. Low and high RDA toothpastes were used for enamel pretreatment. SBS, ARI and failures were recorded. Higher SBS values were found for teeth pretreated with lower RDA agents; conversely, lower SBS values were found for teeth pretreated with higher RDA agents (p < 0.05). For high ARI values, RDA increased too (p > 0.05). In the clinical study, a significantly lower failure rate was reported for teeth pretreated with low RDA toothpaste (2.5% in low RDA group, 7.0% in high RDA group; p < 0.05). No significant differences were assessed comparing the two dental arches and anterior and posterior sites. Enamel pretreatment with low RDA toothpastes could increase brackets' survival rate. Further in vitro and clinical studies would be welcomed to confirm these findings.

Bracket Failure in Orthodontic Patients: The Incidence and the Influence of Different Factors

Failure of brackets is a common problem in orthodontics. This affects the treatment time, cost, and compliance of the patient. This study was conducted to estimate the bracket failure rate and the related factors for the long term. Methodology. This ambidirectional cohort study included 150 nonsyndromic orthodontic patients undergoing fixed appliance therapy for the last two years. The same patients were followed for 7 months. Different variables related to bracket failure were evaluated. The available data were analyzed descriptively, and the Kaplan-Meier estimate was used to measure the bracket survival rate from the date of bonding to failure. Results. A total of 180 bracket bond failures in the 150 included patients (52.2% males and 47.8% females) with a median age of 17 years (range 10-25 years). 69% of brackets failures were reported within the first 6 months after bonding. About 58.3% of bracket failure was noticed in adolescent patients before the age of 18 years. The majority of the cohort (81.1%) has good oral hygiene. The failure rate in patients with normal overbite was 41.1%, in decreased overbite cases was 15%, while in deep bite cases the failure rate was 43.9% with a statistically significant difference. Adults show less bracket failure (41.7%) than adolescent patients (58.3%). More bracket failure was noted in the lower arch (55%) than the upper arch (45%), and there were more bond failures posteriorly (61%) than on the anterior teeth (39%). Majority (41.1%) of the bracket failed on round NiTi wires. Conclusion. The bracket failure rate was 6.4%, with most bracket failure occurring in the first 6 months after bonding with individual difference. There was more incidence of bond failure in an increased overbite, adolescents, lower arch, posterior teeth, and lighter alignment wires.

Effect of using different component combinations for orthodontic bracket bonding with self-etch primers

PURPOSE

To evaluate bonding quality for orthodontic bracket bonding with different component combinations of self-etch primers in vitro.

METHODS

Metallic brackets were bonded to bovine lower incisors and assigned to groups. Group 1: comparison of self-etch (Transbond™ Plus, 3M™ Unitek, Neuss, Germany, n = 30; BrackFix® primer SE, VOCO®, Cuxhaven, Germany, n = 20) and etch-and-rinse bonding systems (Transbond™ XT, n = 20; BrackFix®, n = 20); group 2: comparison of different self-etch primer (Transbond™ Plus; BrackFix® primer SE) and adhesive (Transbond™ XT, n = 20; BrackFix®, n = 20) product combinations; group 3: testing cyclic fatigue bond strength of self-etch bonding systems (Transbond™ Plus, n = 20; BrackFix® primer SE, n = 20). All teeth were tested for shear bond strength according to the DIN-13990 standard, the adhesive remnant index (ARI) and enamel fractures were determined microscopically (10 × magnification).

RESULTS

The mean shear bond strength of the self-etch (Transbond™ Plus: 16.38 ± 3.68 MPa; BrackFix® primer SE: 16.24 ± 1.73 MPa) and etch-and-rinse bonding systems (Transbond™ XT: 18.45 ± 2.56 MPa; BrackFix®: 17 ± 5.2 MPa) were of a clinically adequate order of magnitude (≥ 6-10 MPa) and were not statistically different. The component combination BrackFix® primer SE/Transbond™ XT adhesive led to a significantly lower shear bond strength (11.99 ± 3.68 MPa). There were no significant differences between static and fatigue shear bond strengths of self-etch bonding systems. Mean ARI scores mostly ranged between 4 and 5. The combination of the self-etch primer Transbond™ Plus with the BrackFix® adhesive led to a significantly increased enamel fracture rate.

CONCLUSIONS

Based on the present findings bond strength of self-etch primers was equal to etch-and-rinse primers for bracket bonding. Combining different self-etch bonding systems might alter the clinical performance.

Assessment of preparation time and 1-year Invisalign aligner attachment survival using flowable and packable composites

OBJECTIVES

To compare preparation time and 1-year Invisalign aligner attachment survival between a flowable composite (FC) and a packable composite (PC).

MATERIALS AND METHODS

Fifty-five participants (13 men and 42 women, mean age ± SD: 24.2 ± 5.9 years) were included in the study. Ipsilateral quadrants (ie, maxillary and mandibular right, or vice versa) of attachments were randomly assigned to the FC group (Filtek Z350XT Flowable Restorative) and the PC group (Filtek Z350XT Universal Restorative) by tossing a coin. The primary outcome was preparation time. The secondary outcome was time to the first damage of an attachment. Preparation times were compared using the paired t-test, and the survival data were analyzed by the Cox proportional hazards model with a shared frailty term, with α = .05.

RESULTS

The preparation times were significantly shorter with the FC (6.22 ± 0.22 seconds per attachment) than with the PC (32.83 ± 2.16 seconds per attachment; P < .001). The attachment damage rates were 14.79% for the FC and 9.70% for the PC. According to the Cox models, attachment damage was not significantly affected by the attachment material, sex, arch, tooth location, attachment type, presence of overbite, or occurrence of tooth extraction.

CONCLUSIONS

The use of a FC may save time as compared with the use of a PC. With regard to attachment survival, there was no significant difference between the two composites. None of the covariates of attachment materials (sex, arch, tooth location, attachment type, presence of overbite, oir occurrence of tooth extraction) affected attachment damage.

Effects of Diode and Nd:YAG Laser Irradiation on Friction Forces Between Two Types of Ceramic Brackets and Rhodium-Coated Archwires

Introduction: Ceramic brackets have gained increasing popularity among dental clinicians and orthodontic patients but friction is a major concern when using them. This study sought to assess the effects of diode and Nd:YAG (neodymium-doped yttrium aluminum garnet) laser irradiation on friction forces between two types of ceramic brackets and rhodium-coated esthetic archwires. Methods: Thirty polycrystalline and 30 poly-sapphire brackets were divided into 6 groups (n=10) as follows: (I) control polycrystalline brackets (no laser irradiation), (II) polycrystalline brackets subjected to diode laser irradiation, (III) polycrystalline brackets subjected to Nd:YAG laser irradiation, (IV) control poly-sapphire brackets (no laser irradiation), (V) poly-sapphire brackets subjected to diode laser irradiation, and (VI) poly-sapphire brackets subjected to Nd:YAG laser irradiation. The bracket slots were laser-irradiated on a custom-made table. Sixty 5-cm pieces of rhodium-coated archwires were used for the friction test in a universal testing machine at a speed of 10 mm/min. Ten brackets from the six groups underwent scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). Results: The frictional resistance value of polycrystalline brackets was significantly higher than that of poly-sapphire brackets, irrespective of laser type (P <0.05). Irradiation of diode and Nd:YAG lasers, compared with the control group, had no significant effect on friction, irrespective of bracket type (P >0.05). Conclusion: It appears that diode and Nd:YAG laser irradiation cannot significantly decrease the friction. Future studies are warranted on different laser types with variable exposure.

Factors influencing treatment efficiency

OBJECTIVES

The purpose of this cohort study was to evaluate the effect of self-ligating brackets (SB) and other related factors that influence orthodontic treatment time.

MATERIALS AND METHODS

This was a two-armed prospective study. Consecutively treated patients who were recruited from a private practice were enrolled and asked to choose between SB and conventional brackets (CB). If the patient did not have a preference, that patient was randomly allocated. An identical archwire sequence was used, and all patients were treated by a single orthodontist. Treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, whether or not to orthodontic mini-implants (OMI) were used, OMI failure, extraction, American Board of Orthodontics Discrepancy Index, and arch length discrepancy were measured and statistically analyzed using t-tests, correlation analysis, and analysis of covariance (ANCOVA). Stepwise regression analysis was conducted to generate an equation to predict treatment duration.

RESULTS

A total of 134 patients with an average age of 22.73 years were included. The average treatment duration was 28.63 months. ANCOVA showed no significant difference in treatment duration between CB and SB. Stepwise regression analysis could explain 64.6% of the variance in treatment duration using five variables.

CONCLUSIONS

SB did not exhibit a significant reduction in treatment time as compared with CB. Patient cooperation, extractions, and malocclusion severity had a significant impact on treatment duration.

A Retrospective Clinical Audit of Bracket Failure among Patients Undergoing Orthodontic Therapy

Objective

Bonding failure is a problem in orthodontic therapy and has been associated with orthodontic emergencies and delayed treatment time. The aim of this study is to determine the bracket failure rate among patients undergoing orthodontic therapy.

Materials and Methods

From the archives of posttreatment records, 200 total cases were selected, out of which 122 cases had detailed treatment records. Cases with incomplete records, large restorations, or enamel aberrations were excluded from the study. Descriptive statistics were applied to obtain sample characteristics, and a chi-square test was applied to compare the bracket failure between different categories.

Result

Out of the 122 samples enrolled in the study, female and male patients comprised 71% and 29%, respectively. Class I malocclusions were the most common problem (56%), followed by Class II (41%) and Class III (3%). The bracket failure rate was 3.43%, and 32% of the patients had an incidence of bracket failure. There was no significant difference in bracket failure among genders (p=0.344), malocclusion types (p=0.191), or operators (p=0.188). The maxillary left quadrant was the most common site of bracket failure, followed by the mandibular right quadrant.

Conclusion

Bracket failure is relatively uncommon. It is not affected by the gender or age of the patient or by malocclusion type. The maxillary left and mandibular right quadrants are the most common sites of bracket failure.

Bond strength of metal brackets to feldspathic ceramic treated with different surface conditioning methods: an in vitro study

Purpose:

To compare MEP which is originally manufactured for increasing bond strength between organic resins and ceramic with conventional surface treatment methods in preparation of leucite-reinforced FC surfaces regarding shear bond strength (SBS) of stainless steel brackets and the mode of bond failure.

Materials and methods:

Forty specimens that were fabricated from FC material and glazed were randomly assigned to four surface conditioning methods: (1) CoJet Sand; (2) MEP; (3) HF acid etching followed by silane coupling agent; (4) Diamond bur followed by silane coupling agent. The SBS was determined using universal testing machine. Bond failure sites were classified according to Adhesive Remnant Index (ARI).

Results:

No statistically significant difference (p less than 0.05) was found in SBS between the groups while significant intergroup differences were detected concerning ARI scores (p less than 0.001). Group 1 had ARI score 1 and 2 indicating mode of failure at the adhesive interface with greater percentage of the adhesive left on bracket base. The other groups had higher frequency of ARI score 3 and 2. The quantity of the ARI retained on the ceramic surface was highest in Group 3, followed by Group 4 and Group 2.

Conclusion:

MEP can be a suitable alternative for bonding metal brackets to FC surface.

Analysing the potential of hydrophilic adhesive systems to optimise orthodontic bracket rebonding

Introduction

Bond failure during fixed orthodontic treatment is a frequently occurring problem. As bracket rebonding is associated with reduced shear bond strength, the aim of the present investigation is to analyse the effect of different innovative rebonding systems to identify optimised rebonding protocols for orthodontic patient care.

Methods

Metallic brackets were bonded to the frontal enamel surfaces of 240 bovine lower incisors embedded in resin bases. Teeth were randomly divided into two major experimental groups: in group 1 a hydrophilic primer (Assure™ PLUS) was compared to commonly used orthodontic adhesives (Transbond XT™, BrackFix®, Grengloo™) and a zero control. In group 2 different rebonding systems were analysed using a hydrophilic primer (Assure™ PLUS), a methyl methacrylate-consisting primer (Plastic Conditioner) and a conventional adhesive (Transbond XT™). All teeth were tested for shear bond strength according to the DIN-13990 standard, the Adhesive Remnant Index and enamel fracture rate.

Results

The hydrophilic primer enhanced shear bond strength at first bonding (Assure™ PLUS 20.29 ± 4.95 MPa vs. Transbond XT™ 18.45 ± 2.57 MPa; BrackFix® 17 ± 5.2 MPa; Grengloo™ 19.08 ± 3.19 MPa; Meron 8.7 ± 3.9 MPa) and second bonding (Assure™ PLUS 16.76 ± 3.71 MPa vs. Transbond XT™ 13.06 ± 3.19 MPa). Using Plastic Conditioner did not seem to improve shear bond strength at rebonding (13.57 ± 2.94). When enamel etching was left out, required shear bond strength could not be achieved (Plastic Conditioner + Assure™ PLUS 8.12 ± 3.34 MPa; Plastic Conditioner: 3.7 ± 1.95 MPa). Hydrophilic priming systems showed decreased ARI-scores (second bonding: 2.63) and increased enamel fracture rates (first bonding: 55%; second bonding 21,05%).

Conclusions

Based on the present study we found that rebonding strength could be compensated by the use of hydrophilic priming systems. The additional use of a methyl methacrylate-consisting primer does not seem to enhance shear bond strength. No etching approaches resulted in non-sufficient bond strength.

A Clinical Comparison of Failure Rates of Metallic and Ceramic Brackets: A Twelve-Month Study

Objective

Clinical comparison of the survival rates between stainless steel and ceramic brackets over a 12-month period.

Materials and Methods

The study involved 20 consecutive patients with diagnosed malocclusion that required two-arch fixed appliance treatment. The participants were randomly divided into two 10-member groups. Group 1 was treated with Abzil Agile (3M Unitek) stainless steel brackets; group 2 was treated with Radiance (American Orthodontics) monocrystalline ceramic brackets. All the brackets were bonded by the same operator. Over the next 12 months, all bracket failures were recorded with each appointment. The received data were processed statistically using the Mantel–Cox test, Kaplan–Meier method, and Cox hazard model.

Results

A total of 381 brackets were bonded, 195 of which were metallic brackets and 186 were ceramic ones. In the 12-month observation period, there were 14 metal (7.2%) and 2 ceramic bracket (1.1%) failures. The overall failure rate was 4.2% (n = 16). The majority of failures (14 brackets; 87.5%) occurred during the first 6 months of the experiment, 12 (83%) of which were metal brackets and 2 (100%) were ceramic brackets. The statistical analysis revealed significant differences between the groups (p < 0.05).

Conclusions

Metal brackets demonstrated significantly higher failure rates than ceramic brackets for both 6- and 12-month observation periods (p < 0.05). The 6% difference between the brackets is clinically significant as it corresponds to one additional failure within 12 months.

The influence of enamel sandblasting on the shear bond strength and fractography of the bracket-adhesive-enamel complex tested in vitro by the DIN 13990:2017-04 standard

OBJECTIVES

This study was conducted in order to investigate whether enamel sandblasting as an adjunct or substitute to the acid-etch technique has an effect on the shear bond strength (SBS) and fractography of the bracket-adhesive-enamel complex using the DIN 13990:2017-04 standard.

MATERIALS AND METHODS

Upper central incisor brackets (discovery®, Dentaurum, Germany) were bonded using Transbond XT™ (3M Unitek, Germany) on bovine incisors prepared by four different methods (15 samples each): sandblasting with 27 μm Al₂O₃ at 1.2 bar (s), acid etching with 37.4% phosphoric acid (a), sandblasting with 27 μm Al₂O₃ at 1.2 bar followed by acid etching (s1a), and sandblasting with 50 μm Al₂O₃ at 5.7 bar followed by acid etching (s2a). The SBS and adhesive remnant index (ARI) were measured, followed by one-way analysis of variance and Fisher's exact tests at 5%.

RESULTS

The SBS in groups s (5.6 ± 2.2 MPa), a (17.1 ± 4.3 MPa), s1a (18.3 ± 4.3 MPa), and s2a (18.5 ± 4.6 MPa) indicated that the s group was significantly inferior to all the other groups (p < 0.001). Likewise, the ARI analysis indicated a different performance of the s group (mostly ARI of 0) compared to the other groups (p < 0.001) and a tendency for different ARI between the a and s1a/s2a groups.

CONCLUSIONS

In vitro enamel sandblasting could not substitute acid etching and did not offer improved SBS when used before acid etching, regardless of air pressure and powder granulation. Sandblasting without acid etching produced less residual resin on the tooth after debonding.

CLINICAL RELEVANCE

The clinical use of adjunct enamel sandblasting prior to etching to enhance SBS has to be questioned.

The association between patient's compliance and age with the bonding failure of orthodontic brackets: a cross-sectional study

Background

An efficient orthodontic treatment must aim the best occlusal result in the shortest possible time. One of the factors that can interfere in this goal is the bracket debonding during the treatment. This study aimed at assessing the different factors related to brackets failure, highlighting age and patient cooperation with treatment.

Methods

The sample comprised 199 orthodontic patients of both genders (103 women and 96 men); divided into two groups—adolescents (12 to 18 years old, 118 patients) and adults (19 to 59 years old, 81 patients). A questionnaire was applied regarding the motivation of patients to seek treatment and whether they had received information on appliance care; patients also filled out their level of cooperation with treatment in a visual analog scale (VAS). Additionally, other variables were assessed, such as the teeth with bracket debonding, the presence of deep overbite, and the use of bite plate. The Mann-Whitney test was used, and a 5% significance level was applied for analyses.

Results

It was observed that 20.1% of patients presented at least one tooth with bracket failure, and the lower arch was the most prevalent site (47.5%). Adolescents presented more debonding (25.4%) than adults (12.3%). Individuals with better VAS scores on cooperation sought treatment on their own (p = 0.042), were adults (p ≤ 0.001), and showed lower rate of failure of brackets (p ≤ 0.001). The factors related to malocclusion and treatment performed had no statistical significance.

Conclusion

Greater cooperation was expected from adult individuals who sought treatment on their own and presented low rate of bracket failure.