Hypersensitivity to conventional and to nickel-free orthodontic brackets.

Braz Oral Res. 2007;21(4):298-302

Authors: Pantuzo MC, Zenóbio EG, Marigo HD, Zenóbio MA

The aim of this study was to evaluate the allergenic potential of orthodontic brackets, comparing the cutaneous sensitivity provoked by metals present in conventional metallic brackets to that provoked by brackets with a low concentration of nickel, known as "nickel-free". A sample was selected from 400 patients undergoing treatment in the orthodontic clinic of the Pontifical Catholic University of Minas Gerais (Belo Horizonte, MG, Brazil), in the period from the beginning of 2002 to the end of 2003. A cutaneous sensitivity patch test containing 5% nickel sulphate was used in 58 patients (30 males and 28 females), aged between 11 and 30, which were using fixed appliances with Morelli(R) brackets in both arches. In a second phase, 30 days later, a comparative test of cutaneous sensitivity was applied to the whole sample with two types of test specimens, in the form of a disc. Two alloys were tested: discs composed of the alloy used in the construction of conventional brackets and discs composed of a nickel-free alloy. The internal part of the forearm was chosen for testing, and 20 test specimens of each experiment (corresponding to the twenty brackets of a complete fixed appliance) were applied. Of the 58 patients evaluated, 16 patients were sensitive to the patch test with 5% nickel sulphate. Out of these 16 patients, 12 developed an allergic reaction to experiment 1 (test specimen with nickel), while in experiment 2, only 5 patients showed sensitivity to that sample. The McNemar test revealed that the nickel-free test specimens provoked less allergic reaction when compared with the conventional alloy (p = 0.016).

PMID: 18060254 [PubMed - as supplied by publisher]

Effect of different types of enamel conditioners on the bond strength of orthodontic brackets.

J Contemp Dent Pract. 2007 Jan 1;8(1):36-43

Authors: Davari AR, Yassaei S, Daneshkazemi AR, Yosefi MH

AIM: A unique characteristic of some new bonding systems in operative dentistry is they combine conditioning and priming agents into a single acidic primer solution for simultaneous use on both enamel and dentin. Combining conditioning and priming into a single treatment step results in improvement in both time and cost-effectiveness to the clinician and, indirectly, to the patient. The purpose of this study was to determine the effects of the use of a self-etching primer on the bond strength of orthodontic brackets and on the bracket/adhesive failure mode. METHODS AND MATERIALS: Thirty-six fresh bovine incisors were collected and stored in a solution of 0.1% (weight/volume) thymol. The criteria for tooth selection included intact buccal enamel, no cracks caused by the presence of the extraction forceps, and no defects. The teeth were cleansed and polished with pumice and rubber prophylactic cups for ten seconds. Brackets were bonded to the teeth according to one of three protocols following the manufacturers' instructions--Group 1: Conventional multistep bonding system (control group) (n=12); Group 2: Self-etching primer system (n=12); and Group 3: Acid+self-etching primer system (n=12). Specimens were loaded to failure in a Zwick test machine (Zwick GmbH & Co, Ulm, Germany). Shear bond strengths were measured at a crosshead speed of 5 mm/min. RESULTS: The mean shear bond strength in megapascals (Mpa) (standard deviation) were 11.7 (4.2), 10.5 (4.4), and 10.9 (4.8) for Groups 1, 2, and 3, respectively. The analysis of variance (ANOVA) was used to compare the three groups. The results indicated no significant difference in the bond strength between the three groups (P=0.800). The results of the Chi square test, evaluating the residual adhesives on the enamel surfaces, revealed no significant difference between the three groups (P=0.554). CONCLUSION: Results of the present in vitro study indicate the use of self-etching primers may be an alternative to conventional phosphoric acid pre-treatment in orthodontic bonding.

PMID: 17211503 [PubMed - indexed for MEDLINE]

A randomized clinical trial comparing 'one-step' and 'two-step' orthodontic bonding systems.

J Orthod. 2006 Dec;33(4):276-83; discussion 256-7

Authors: Manning N, Chadwick SM, Plunkett D, Macfarlane TV

OBJECTIVE: The primary objective of this prospective clinical trial was to assess the clinical bond failure rates of orthodontic brackets bonded using a self-etching primer (SEP), compared with brackets bonded using a conventional acid-etched technique with control adhesive (Transbond). A secondary aim was to investigate whether characteristics of the operator, patient or tooth bonded had any influence on bracket failure. DESIGN: Single-centre randomized controlled clinical trial. Thirty-four patients were bonded, each being randomly assigned to either the test or control adhesive. SETTING: NHS Hospital Orthodontic Department, Chester, UK. SUBJECTS: Orthodontic patients requiring fixed appliance treatment. MAIN OUTCOME MEASURES: Bond failure. MAIN OUTCOME RESULTS: Failure rates over the initial 6-month period were 2.0% (Transbond) and 1.7% (SEP) with no statistically significant difference between the two groups. Over the duration of the fixed appliance treatment, bond failure rates increased, but remained acceptable at 7.4 % (TB) and 7.0% (SEP), respectively. When operator, patient and tooth characteristics were analysed, only the bracket location was found to be significant. Maxillary brackets were more likely to fail than mandibular brackets (RR 0.47%; 95% CI 0.22, 1.03). The failure rate for brackets in our study was low when compared with previous studies. CONCLUSIONS: Both the acid-etched control and self-etching primer in combination with adhesive pre-coated brackets were successful for clinical bonding. Their combined failure rate was lower than that reported in similar trials.

PMID: 17142334 [PubMed - indexed for MEDLINE]

A clinical comparison of bracket bond failures in association with direct and indirect bonding.

J Orthod. 2006 Sep;33(3):198-204

Authors: Thiyagarajah S, Spary DJ, Rock WP

Objective: To compare bond failure rates between direct and indirect techniques for bonding orthodontic brackets. Design: A two-centre single blinded prospective randomized controlled clinical trial. Materials and methods: This study was undertaken at the Birmingham Dental Hospital and Good Hope Hospital, Sutton Coldfield. Thirty-three subjects meeting the inclusion criteria were selected from orthodontic waiting lists and assigned to either of two study groups according to a split-mouth study design. The number and site of bracket failures between tooth types was recorded over 1 year. Statistical analysis was carried out using chi-square tests. Results: Brackets were lost from 14 of the 553 teeth bonded, giving an overall bond failure rate of 2.5%. There were no significant differences in bond failures between direct and indirect bonding or in the tooth types of the failures. CONCLUSIONS: There was no significant difference in the bond failure rates between direct and indirect bonding.

PMID: 16926313 [PubMed - as supplied by publisher]

Normal torque of the buccal surface of mandibular teeth and its relationship with bracket positioning: a study in normal occlusion.

Braz Dent J. 2006;17(2):155-60

Authors: Mestriner MA, Enoki C, Mucha JN

This study evaluated the degree of buccolingual inclination of mandibular tooth crowns relative to torque. For such purpose, mandibular and maxillary stone casts from 31 Caucasian Brazilian adults with normal occlusion, pleasant facial aspect and no history of previous orthodontic treatment were examined. A custom device was developed for measuring the degree of inclination (torque) of bracket slots of orthodontic appliances relative to the occlusion plane, at three bonding height: standard (center of clinical crown), occlusal (0.5 mm occlusally from standard) and cervical (0.5 mm cervically from standard). Except for the mandibular incisors, which presented a small difference in torque from one another (lingual root torque for central incisors and buccal root torque for lateral incisors), the remaining average values are close to those found in the literature. Due to the convexity of the buccal surface, the 1-mm vertical shift of the brackets from occlusal to cervical affected the values corresponding to the normal torque, in approximately 2 degrees in central and lateral incisors, 3 degrees in canines and 8 degrees in premolars and molars.

PMID: 16924345 [PubMed - indexed for MEDLINE]

Porcelain surface-conditioning techniques and the shear bond strength of ceramic brackets.

Eur J Orthod. 2006 Oct;28(5):440-3

Authors: Türkkahraman H, Küçükesmen HC

The aim of this study was to compare the effects of various porcelain surface-conditioning techniques, used either alone or in combination, on the shear bond strength (SBS) of ceramic brackets cured with a light emitting diode (LED). Thirty glazed porcelain facets were randomly divided into three groups of 10. In group I, the porcelain surfaces were etched with 9.6 per cent hydrofluoric acid (HFA) for 2 minutes before silane application, in group II, the porcelain surfaces were sandblasted with aluminium oxide particles, etched with 9.6 per cent HFA for 2 minutes, and silane applied, and in group III, the porcelain surfaces were sandblasted with aluminium oxide particles before silane application. Spirit ceramic brackets were bonded with a light-cured composite resin (Light Bond) and a LED. All specimens were stored in distilled water at 37 degrees C for 24 hours and thermocycled. Bond strength was determined in shear mode at a crosshead speed of 0.5 mm/minute until fracture occurred. Analysis of variance indicated a significant difference between groups (P < 0.001). The lowest SBS was found in group III (5.46 +/- 1.34, P < 0.001). No significant difference was found between group I (11.38 +/- 1.65) and group II (10.45 +/- 1.15; P > 0.05). Surface treatment with HFA and a silane coupling agent produced the highest bond strength. Sandblasting before HFA and silane application did not significantly increase bond strength. Silane application to sandblasted porcelain provided poor results in vitro and clinical trials are needed to determine its reliability for bonding ceramic brackets to ceramic crowns.

PMID: 16916898 [PubMed - indexed for MEDLINE]

Surgical and orthodontic treatment of an impacted permanent central incisor: a case report.

J Indian Soc Pedod Prev Dent. 2006 Jun;24(2):100-3

Authors: Thosar NR, Vibhute P

Although impaction of a permanent tooth is rarely diagnosed during the mixed dentition period, an impacted central incisor is usually diagnosed accurately when there is delay in the eruption of tooth. In this article, the impacted incisor was moved into it's proper position with surgical exposure and orthodontic traction, after which it showed good stability.

PMID: 16823236 [PubMed - indexed for MEDLINE]

Effects of surface conditioning on bond strength of metal brackets to all-ceramic surfaces.

Eur J Orthod. 2006 Oct;28(5):450-6

Authors: T&#xFC;rk T, Saraç D, Saraç YS, Elekdağ-Türk S

The aim of this study was to determine the effectiveness of bonding brackets to ceramic restorations. Sixty feldspathic and 60 lithium disilicate ceramic specimens were randomly divided into six groups. Shear bond strength (SBS) and bond failure types were examined with six surface-conditioning methods: silane application to glazed surface, air particle abrasion (APA) with 25- and 50-microm aluminium trioxide (Al(2)O(3)), etching with 9.6 per cent hydrofluoric acid (HFA), and roughening with 40- and 63-microm diamond burs. Silane was applied to all roughened surfaces. Metal brackets were bonded with light cure composite, then stored in distilled water for 1 week and thermocycled (x500 at 5-55 degrees C for 30 seconds). The ceramic surfaces were examined with a stereomicroscope at a magnification of x10 to determine the amount of composite resin remaining using the adhesive remnant index. The lowest SBS values were obtained with HFA for feldspathic (5.39 MPa) and lithium disilicate (11.11 MPa) ceramics; these values were significantly different from those of the other groups. The highest SBS values were found with 63-microm diamond burs for feldspathic (26.38 MPa) and lithium disilicate (28.20 MPa) ceramics, and were not significantly different from 40-microm diamond burs for feldspathic and lithium disilicate ceramics (26.04 and 24.26 MPa, respectively). Roughening with 25- and 50-microm Al(2)O(3) particles showed modest SBS for lithium disilicate (22.60 and 26.15 MPa, respectively) and for feldspathic ceramics (17.90 and 14.66 MPa, respectively). Adhesive failures between the ceramic and composite resin were noted in all groups. Damage to the porcelain surfaces was not observed. The SBS values were above the optimal range, except for feldspathic ceramic treated with HFA and silane. With all surface-conditioning methods, lithium disilicate ceramic displayed higher SBS than feldspathic ceramic.

PMID: 16772317 [PubMed - indexed for MEDLINE]

A randomised clinical trial to investigate bond failure rates using a self-etching primer.

Eur J Orthod. 2006 Oct;28(5):444-9

Authors: Murfitt PG, Quick AN, Swain MV, Herbison GP

This clinical trial evaluated, over a 12-month period, the performance of brackets bonded to teeth etched and primed with Transbond Plus Self-Etching Primer (SEP) when compared with a conventional separate two-step etch and primer system. Thirty-nine randomly selected patients requiring fixed appliance therapy were entered into the study. Random allocation of each etching system, along with a 'split-mouth cross-quadrant' design was used. A total of 661 brackets were placed by two operators. The failure and survival rates of the brackets were determined for age and gender of the patients, each etching system, operator, mode of failure, tooth position in the dental arch, and number of manipulations prior to curing the adhesive. Statistical analysis showed that SEP had a significantly higher bond failure rate (11.2 per cent) than the conventional etch and primer system (3.9 per cent) at the P = 0.001 level. Cox's proportional hazards regression showed the conventional etch and primer system to have a 60 per cent reduced chance of bracket failure over a 12-month observation period, while males had a 2.4 times increased risk compared with females. The predominant mode of failure was at the composite enamel interface for the SEP, while for the conventional etch and primer system, it was within the composite adhesive. No statistically significant differences were found for the failure rate with respect to the age of the patient, operator, tooth location, or the number of manipulations of the bracket. This in vivo study showed that brackets bonded using SEP had an increased clinical bond failure rate compared with the conventional, separate, etch and prime system.

PMID: 16763088 [PubMed - indexed for MEDLINE]

Evaluation of an antimicrobial and fluoride-releasing self-etching primer on the shear bond strength of orthodontic brackets.

Eur J Orthod. 2006 Oct;28(5):457-61

Authors: Korbmacher H, Huck L, Adam T, Kahl-Nieke B

The enhanced risk of dental caries is one negative side-effect of fixed appliances. A new antimicrobial and fluoride-releasing self-etching bonding system (Clearfil Protect Bond) has been introduced in restorative dentistry and clinical studies have already shown the potential for this primer to be used clinically with effective antiplaque properties. Therefore, this in vitro study was conducted in order to evaluate the new primer in comparison with a conventional bonding preparation. One hundred and twenty extracted human teeth were randomly divided into three groups of 40 specimens each (20 incisors, 20 premolars). In group 1 a conventional bonding procedure was used (etching, Transbond XT), in group 2 the new primer was used according to the manufacturer's recommendations when bonding to intact enamel, while in group 3 the new primer was used without prior etching. Shear bond strength (SBS) was measured with a universal testing machine and the adhesive remaining after debonding was determined using an optical microscope at x10 magnification. The adhesive remnant index was used in order to assess the mode of failure. No enamel fractures were detected in any of the specimens. In all groups acceptable bond strengths were observed. The only statistically significant difference (P = 0.004) was found for the incisors in group 2, which showed the highest mean SBS (17.46 MPa). Considering the acceptable bond strength and the mode of failure, use of the new primer without prior etching is recommended in patients with fixed appliances. Further in vivo studies will be carried out in order to evaluate clinical performance.

PMID: 16763086 [PubMed - indexed for MEDLINE]

An in-vitro investigation into the use of a single component self-etching primer adhesive system for orthodontic bonding: a pilot study.

J Orthod. 2006 Jun;33(2):116-24

Authors: House K, Ireland AJ, Sherriff M

OBJECTIVE: This pilot study assessed force to debond (N); time, and site of bond failure of a single component self-etching primer (SEP) and adhesive system, Ideal 1 (GAC International Inc., USA) and compared it with the conventional acid etch and rinse regimen using 37% o-phosphoric acid solution and either Transbond XT (3M Unitek) or Ideal 1 adhesive. DESIGN: In vitro laboratory study. SETTING: Bristol Dental Hospital, UK. Sept 2003-Sept 2004. MATERIAL AND METHODS: Nine groups of 20 premolars were bonded using metal orthodontic brackets using three protocols: (1) 37% o-phosphoric acid etch and Transbond XT adhesive; (2) 37% o-phosphoric acid and Ideal 1 adhesive; (3) Ideal 1 SEP and Ideal 1 adhesive. Force to debond and locus of bond failure were determined at three time intervals. RESULTS: Enamel pre-treatment prior to bonding, namely SEP versus conventional etching had no significant effect on the median force to debond with the Ideal 1 adhesive. Similarly, when the enamel was conventionally etched, the adhesive type, namely Ideal 1 or Transbond XT, had no significant effect on the measured force to debond. However, there appeared to be differences in the locus of bond failure: failure predominated at the enamel/adhesive interface for the Transbond XT conventional etch group and at adhesive/bracket interface for the Ideal 1 SEP and adhesive group and the Ideal 1 adhesive conventional etch group. CONCLUSION: These results suggested that the complete Ideal 1 SEP and adhesive system might be successful in vivo leading therefore to a clinical trial. However, implications for clean up time are discussed and improvements to in vitro study designs are advised.

PMID: 16751433 [PubMed - indexed for MEDLINE]

The benefits of aesthetic orthodontic brackets in patients requiring multiple MRI scanning.

J Orthod. 2006 Jun;33(2):90-4

Authors: Harris TM, Faridrad MR, Dickson JA

MRI scans are increasingly used diagnostically in medicine. Scans of the head and neck region can be distorted by metallic components in the vicinity. This paper discusses the consideration for aesthetic brackets (with no metal components) on all teeth including molars in patients requiring MRI scans and especially if those need to be repeated on a regular basis.

PMID: 16751430 [PubMed - indexed for MEDLINE]

Shear bond strength of new and recycled brackets to enamel.

Braz Dent J. 2006;17(1):44-8

Authors: Tavares SW, Consani S, Nouer DF, Magnani MB, Nouer PR, Martins LM

The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-microm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm2), brackets recycled by aluminum oxide blasting (0.34 kgf/mm2) and new brackets attached to previously bonded teeth (0.43 kgf/mm2). Brackets recycled by the specialized company (0.28 kgf/mm2) and those recycled by silicon carbide stone grinding (0.14 kgf/mm2) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/mm2) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-microm aluminum oxide particle air-abrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.

PMID: 16721464 [PubMed - indexed for MEDLINE]

An investigation into the use of a single component self-etching primer adhesive system for orthodontic bonding: a randomized controlled clinical trial.

J Orthod. 2006 Mar;33(1):38-44; discussion 28

Authors: House K, Ireland AJ, Sherriff M

OBJECTIVE: This study assessed the in vivo bond failure of the single component orthodontic self-etching primer system, Ideal 1 (GAC Orthodontic Products) and compared it with the conventional acid etching using a conventional 37% o-phosphoric acid, rinsing and drying regimen when bonding stainless steel orthodontic brackets to enamel. DESIGN: Prospective randomized, controlled clinical trial. SETTING: Orthodontic Department, Bristol Dental School. MATERIAL AND METHODS: Twenty consecutive patients undergoing upper and lower fixed orthodontic treatment entered this cross-mouth control study. Diagonally opposite quadrants were randomly allocated to either the self-etching primer group or the conventional etching group. A total of 339 teeth were bonded with Ideal 1 light-cured adhesive. Bond failures and locus of bond failure were then recorded at 1, 6 and 12 months. RESULTS: Significantly more bond failures occurred at each of the 3 time intervals, 1, 6 and 12 months, where the enamel was pretreated with the Ideal I self-etching primer, than when the enamel was treated with the conventional etchant, 37% o-phosphoric acid. With the latter the cumulative bond failure rates were 3.0, 5.3 and 14.8%, respectively. With the self-etching primer the cumulative failure rates were 29.4, 56.5 and 72.4%. CONCLUSION: The study found that enamel pre-treatment with the Ideal 1 self-etching primer system prior to orthodontic bonding results in an unacceptably high bond failure rate when compared with conventional enamel acid etching.

PMID: 16514132 [PubMed - indexed for MEDLINE]

Molar band re-use and decontamination: a survey of specialists.

J Orthod. 2006 Mar;33(1):30-7; discussion 28

Authors: Dowsing P, Benson PE

OBJECTIVE: To determine the pattern of use and re-use of orthodontic molar bands, and examine infection control measures in a sample of UK orthodontists. DESIGN: Questionnaire survey. SUBJECTS AND METHODS: Questionnaires were sent to 204 individuals selected at random from the UK Specialist Orthodontist list. Follow-up questionnaires were sent to those that had not replied within 8 weeks. An overall response rate of 74.5% was achieved. MAIN OUTCOME MEASURES: Orthodontic band use and re-use and cross-infection control. RESULTS: The reported rates of pre-sterilization cleaning and sterilization of orthodontic instruments were 92 and 100%, respectively. Of the respondents, 90% were using bands for molar teeth with the remainder routinely used bonded attachments. Most clinicians (95%) using bands routinely re-used them after being tried-in with 5% discarding them. Pre-sterilization cleaning of re-used molar bands was carried out by 92% of respondents who reclaimed bands. Sterilization of these bands was then carried out by most specialists apart from 2. CONCLUSIONS: The majority of UK specialist orthodontists who responded to the questionnaire are adhering to universal precautions for cross-infection control and are carrying out approved decontamination procedures. The majority are also reusing orthodontic bands that have been tried in the mouth, but found to be the wrong size. The great diversity of reported procedures for decontamination of instruments and bands suggest that more research is required to provide guidelines into the most effective method.

PMID: 16514131 [PubMed - indexed for MEDLINE]

Bonding characteristics of a self-etching primer and precoated brackets: an in vitro study.

Eur J Orthod. 2006 Aug;28(4):400-4

Authors: Hirani S, Sherriff M

Little is known about the performance of Transbond Plus Self-Etching Primer (TPSEP), especially when used with Adhesive Precoated Brackets (APC 1 and APC 2). The aim of this study was to compare the shear bond and rebond strengths and failure sites of APC 1 and APC 2 with a non-coated bracket system [Victory Series (V)] using Transbond XT light-cured adhesive and TPSEP or 37 percent phosphoric acid as the conditioner. The results demonstrated that on dry testing of 120 brackets when applying an occluso-gingival load to produce a shear force at the bracket-tooth interface, there was no statistically significant difference in the shear bond strength (SBS) of APC 1 (68.4 N), APC 2 (74.9 N), and V brackets (75.4 N, control group). There was also no significant difference in bond failure sites of the APC 1 and APC 2 when compared with the non-coated bracket system using Transbond XT light-cured adhesive and TPSEP, with bond failure for all groups occurring mainly at the adhesive-enamel interface. There was a significant difference in the SBS of the V brackets when using TPSEP and 37 percent phosphoric acid as the conditioners. The latter was lower (60.6 N) and the bond failure site changed from the enamel-adhesive interface to the bracket-adhesive interface. The shear rebond strengths of all bracket types were statistically significantly lower (P < 0.05) than their initial SBS (APC 1, APC 2, and V: 35.9, 36.7, and 34.1 N, respectively) and the locus of bond failure altered from the adhesive-enamel interface to the bracket-adhesive interface. A clinical trial using TPSEP as a conditioner would be useful as the time taken to remove the adhesive from the enamel surface may be reduced following debond.

PMID: 16495372 [PubMed - indexed for MEDLINE]

Self-etching primer and a non-rinse conditioner versus phosphoric acid: alternative methods for bonding brackets.

Eur J Orthod. 2006 Apr;28(2):173-8

Authors: Vicente A, Bravo LA, Romero M

The objective of this study was to evaluate the effectiveness of a self-etching primer, Transbond Plus Self Etching Primer (TSEP, 3M Unitek), and a non-rinse conditioner (NRC, Dentsply DeTrey) for bonding brackets, compared with the acid-etch technique. The brackets were bonded to extracted premolars using Transbond XT (3M Unitek). One of the following three conditioning protocols were used: (1) 37 per cent phosphoric acid (n = 25), (2) TSEP (n = 25), and (3) NRC (n = 15). Shear bond strength (SBS) was measured with a universal testing machine. The adhesive remaining after debonding was determined using image analysis equipment. Scanning electron microscope (SEM) observations were also carried out on 12 premolars to observe the enamel surfaces. No significant differences were observed in SBS between the three groups (P = 0.56). TSEP and NRC left significantly less adhesive on the tooth than the traditional acid-etch technique (P = 0.004 and P = 0.000, respectively). NRC left significantly less adhesive than TSEP (P = 0.001). SEM observations showed that NRC produced a less aggressive etch pattern than TSEP, and that the etching effect of TSEP approximated that of phosphoric acid.

PMID: 16428256 [PubMed - indexed for MEDLINE]

Galvanic corrosion between orthodontic wires and brackets in fluoride mouthwashes.

Eur J Orthod. 2006 Jun;28(3):298-304

Authors: Schiff N, Boinet M, Morgon L, Lissac M, Dalard F, Grosgogeat B

The aim of this investigation was to determine the influence of fluoride in certain mouthwashes on the risk of corrosion through galvanic coupling of orthodontic wires and brackets. Two titanium alloy wires, nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi), and the three most commonly used brackets, titanium (Ti), iron-chromium-nickel (FeCrNi) and cobalt-chromium (CoCr), were tested in a reference solution of Fusayama-Meyer artificial saliva and in two commercially available fluoride (250 ppm) mouthwashes, Elmex and Meridol. Corrosion resistance was assessed by inductively coupled plasma-atomic emission spectrometry (ICP-MS), analysis of released metal ions, and a scanning electron microscope (SEM) study of the metal surfaces after immersion of different wire-bracket pairs in the test solutions. The study was completed by an electrochemical analysis. Meridol mouthwash, which contains stannous fluoride, was the solution in which the NiTi wires coupled with the different brackets showed the highest corrosion risk, while in Elmex mouthwash, which contains sodium fluoride, the CuNiTi wires presented the highest corrosion risk. Such corrosion has two consequences: deterioration in mechanical performance of the wire-bracket system, which would negatively affect the final aesthetic result, and the risk of local allergic reactions caused by released Ni ions. The results suggest that mouthwashes should be prescribed according to the orthodontic materials used. A new type of mouthwash for use during orthodontic therapy could be an interesting development in this field.

PMID: 16428255 [PubMed - indexed for MEDLINE]

Influences of bracket bonding on mutans streptococcus in plaque detected by real time fluorescence-quantitative polymerase chain reaction.

Chin Med J (Engl). 2005 Dec 5;118(23):2005-10

Authors: Ai H, Lu HF, Liang HY, Wu J, Li RL, Liu GP, Xi Y

BACKGROUND: Enamel demineralization occurs frequently during orthodontic treatment. In this study, we evaluated the changes of the density of mutans streptococcus (MS) in plaque after bracket bonding and using fluoride adhesive on maxillary incisors by real time fluorescence-quantitative polymerase chain reaction (RT-FQ PCR). METHODS: The study was designed as a self-paired test. Brackets were bonded with fluoride adhesive on the left side, while non-fluoride adhesive on the right side for each patient. Plaque samples were taken from the surfaces around the brackets of four maxillary incisors before brackets bonding and after the bonding 4 weeks later. The amount of MS was measured by RT-FQ PCR. The data obtained were analyzed statistically using the SPSS 11.5 version and the alpha level was set at 0.05 (2-tailed). RESULTS: The amount of MS in plaque increased significantly after bracket bonding (P < 0.01), whereas no significant differences were observed among four maxillary incisors both before and after brackets bonding (P > 0.05), and among the incisors using and not using fluoride adhesive (P > 0.05). CONCLUSIONS: The increase of the density of MS in plaque after bracket bonding is one of the etiological factors for enamel demineralization in orthodontic patients. The result of this study did not support what we observed clinically that the incidence of enamel demineralization for lateral incisors was higher than that for central incisors. Using fluoride adhesive for bonding did not affect the amount of MS in plaque in our study. Further study is needed.

PMID: 16336838 [PubMed - indexed for MEDLINE]

How to ... debond Clarity brackets with ease.

J Orthod. 2005 Dec;32(4):269-71

Authors: Lee RT

Debonding ceramic brackets has been difficult due to problems with enamel fractures, enamel tears and patient discomfort. New brackets have weaker bases and the debonding technique has changed, with a recommendation that a pair of Mathieu needle holding pliers is used with Clarity brackets.

PMID: 16333049 [PubMed - indexed for MEDLINE]

Clinical pearl: clinical tips with System-R.

J Orthod. 2005 Dec;32(4):244-6

Authors: Parkin N

The article describes the versatility and ease of use of a relatively new bracket system manufactured by GAC called System-R. This system consists of two bracket types; standard width and reduced width, both of which have an active self-ligating clip. The reduced friction offered by this system allows different mechanics to be employed. Security of ligation and absence of decaying force values allows longer treatment intervals. Fast and reliable opening and closing of the clips means reduced chairside time. Difficulties experienced personally by these brackets are highlighted and some troubleshooting tips are included.

PMID: 16333045 [PubMed - indexed for MEDLINE]

A prospective, randomized clinical study on the effects of an amine fluoride/stannous fluoride toothpaste/mouthrinse on plaque, gingivitis and initial caries lesion development in orthodontic patients.

Eur J Orthod. 2006 Feb;28(1):8-12

Authors: &#xD8;gaard B, Alm AA, Larsson E, Adolfsson U

The aim of this study was to examine the effect of combined use of a toothpaste/mouthrinse containing amine fluoride/stannous fluoride (AmF/SnF2; meridol) on the development of white spot lesions, plaque, and gingivitis on maxillary anterior teeth in orthodontic patients. A prospective, randomized, double-blind study with 115 orthodontic patients (42 males and 73 females, average age 14.4 years, drop outs 18) was designed. Group A (50) brushed twice daily with an AmF/SnF2 toothpaste (1400 ppm F) and rinsed every evening with an AmF/SnF2 solution (250 ppm F). Group B (47) brushed twice daily with a sodium fluoride (NaF) toothpaste (1400 ppm F) and rinsed every evening with a NaF solution (250 ppm F). Visible plaque index (VPI), gingival bleeding index (GBI) and white spot lesion index (WSL) were recorded on the six maxillary anterior teeth at bonding and after debonding, and evaluated with t tests. In group A no significant differences between bonding and debonding were recorded for WSL (1.02 +/- 0.08 versus 1.05 +/- 0.13, P = 0.14), VPI (0.10 +/- 0.21 versus 0.12 +/- 0.21, P = 0.66) or GBI (0.13 +/- 0.21 versus 0.16 +/- 0.22, P = 0.47), whereas statistically significant differences were found in group B between bonding and debonding for WSL (1.00 +/- 0.02 versus 1.08 +/- 0.17, P = 0.01), VPI (0.06 +/- 0.13 versus 0.17 +/- 0.25, P = 0.01) and GBI (0.06 +/- 0.12 versus 0.16 +/- 0.21, P = 0.01). The increase in lesions on the upper anterior teeth was 4.3 per cent in group A and 7.2 per cent in group B. It was concluded that the combined use of an AmF/SnF2 toothpaste/mouthrinse had a slightly more inhibitory effect on white spot lesion development, plaque and gingivitis on maxillary anterior teeth during fixed orthodontic treatment compared with NaF.

PMID: 16230329 [PubMed - indexed for MEDLINE]

An investigation into the bonding of orthodontic attachments to porcelain.

Eur J Orthod. 2006 Feb;28(1):74-7

Authors: Larmour CJ, Bateman G, Stirrups DR

This study assessed bonding of orthodontic brackets to porcelain teeth using two different surface preparation techniques and comparing two bonding systems, Fuji Ortho L.C. and Transbond. Four groups of 20 porcelain premolar teeth were bonded with metal orthodontic brackets (0.022 inch Minitwin, 3M Unitek) according to the following protocol: Transbond with a phosphoric acid etch (group 1), Transbond with a hydrofluoric acid etch (group 2), Fuji Ortho L.C. with a hydrofluoric acid etch (group 3), and Fuji Ortho L.C. with a phosphoric acid etch (group 4). All groups were bonded with a silane coupling agent. The teeth were debonded with an Instron universal testing machine. Bond strength, site of bond failure and adhesive remnant index (ARI) were recorded for each group. Differences between groups were analysed statistically. The composite resin groups (groups 1 and 2) had the highest mean bond strength values at 7.9 and 9.7 MPa, respectively. The resin-modified glass ionomer cement groups (RMGIC; groups 3 and 4) had the lowest mean bond strength values at 6.3 and 1.8 MPa, respectively. The mean bond strength of group 3 was significantly lower than all other groups (P < 0.0001). The Fuji groups had also significantly (P < 0.001) lower ARI scores than the composite groups (groups 1 and 2). Most samples experienced porcelain surface damage, except group 4. In conclusion, the highest bond strength levels were achieved with a conventional composite resin cement (groups 1 and 2). No significant differences in bond strength were found between the hydrofluoric and phosphoric acid etch technique.

PMID: 16199411 [PubMed - indexed for MEDLINE]

A comparison of tungsten-quartz-halogen, plasma arc and light-emitting diode light sources for the polymerization of an orthodontic adhesive.

Eur J Orthod. 2006 Feb;28(1):78-82

Authors: Thind BS, Stirrups DR, Lloyd CH

This study investigated whether there were differences between the debond stress and adhesive remnant index (ARI) of an adhesive cured with three different orthodontic light sources. Sixty sound premolar teeth were divided into three groups of 20. A standard pre-adjusted edgewise premolar bracket (Victory Series) was bonded to each tooth using a light-cured orthodontic adhesive, Transbond X. Group 1 (control) specimens were cured with an Ortholux XT (tungsten-quartz-halogen bulb) light for 20 seconds, group 2 with an Ortho lite (plasma arc) for 6 seconds and group 3 with an Ortholux LED light-emitting diode for 10 seconds. The specimens were debonded 24 hours later using a universal mechanical testing machine, operating at a crosshead speed of 0.5 mm minute(-1). The Weibull modulus and a Logrank test showed no statistically significant differences between the three groups for debond stress. The ARI was assessed at x10 magnification. The ARI scores for group 2 were significantly different (P < 0.01) from those of groups 1 and 3 (between which there was no significant difference). For group 2 there was a greater tendency for failure to occur at the adhesive/tooth interface than for the other two groups. There appears to be no reason why any of the three types of light source cannot be used in orthodontics. Polymerization, as effective as that produced by conventional bulb light sources, was obtained with the short exposure times recommended for the plasma arc or light-emitting diode sources.

PMID: 16199410 [PubMed - indexed for MEDLINE]

Clinical pearl In-treatment replacement of missing incisors.

J Orthod. 2005 Sep;32(3):182-4

Authors: Hodge TM

Four methods of in-treatment replacement of missing incisors are described.

PMID: 16170059 [PubMed - indexed for MEDLINE]

The influence of accelerating the setting rate by ultrasound or heat on the bond strength of glass ionomers used as orthodontic bracket cements.

Eur J Orthod. 2005 Oct;27(5):472-6

Authors: Algera TJ, Kleverlaan CJ, de Gee AJ, Prahl-Andersen B, Feilzer AJ

Conventional glass ionomer cements (GICs) may be a viable option for bracket bonding when the major disadvantages of these materials, such as the slow setting reaction and the weak initial bond strength, are solved. The aim of this in vitro study was to investigate the influence of ultrasound and heat application on the setting reaction of GICs, and to determine the tensile force to debond the brackets from the enamel. A conventional fast-setting GIC, Fuji IX Fast, and two resin-modified glass ionomer cements (RMGICs), Fuji Ortho LC and Fuji Plus, were investigated. Three modes of curing were performed (n = 10): (1) according to the manufacturer's prescription, (2) with 60 seconds application of heat, or (3) with 60 seconds application of ultrasound. The tensile force required to debond the brackets was determined as the tension 15 minutes after the start of the bonding procedure. The mode of failure was scored according to the Adhesive Remnant Index (ARI) to establish the relative amount of cement remnants on the enamel surface. Curing with heat and ultrasound shortened the setting reaction and significantly (P < 0.05) increased the bond strength to enamel. The ARI scores showed an increase for all materials after heat and ultrasound compared with the standard curing method, most notably after heat application.

PMID: 16049039 [PubMed - indexed for MEDLINE]

Corrosion resistance of three orthodontic brackets: a comparative study of three fluoride mouthwashes.

Eur J Orthod. 2005 Dec;27(6):541-9

Authors: Schiff N, Dalard F, Lissac M, Morgon L, Grosgogeat B

In the present study, three types of orthodontic brackets were investigated: cobalt-chromium (CoCr), iron-chromium-nickel (FeCrNi) and titanium (Ti) based. Their corrosion resistance was compared with that of platinum (Pt), which was chosen as the reference material because of its excellent electrochemical properties. The test solutions were Elmex, Meridol and Acorea fluoride mouthwashes. Fusayama Meyer artificial saliva was used as the reference solution. The corrosion resistance of the different brackets in the three mouthwashes was assessed electrochemically to determine the corrosion potential and corrosion current density, and polarization resistance values were then calculated. A scanning electron microscopic (SEM) study and an analysis of released metal ions confirmed the electrochemical studies. The results showed that the bracket materials could be divided into two groups: Ti and FeCrNi in one, and CoCr, which has properties close to those of Pt, in the other. Similarly, two groups of electrolytes were identified: Elmex and Acorea mouthwashes in one group, and Meridol mouthwash in the second group. The results indicate that because of the risk of corrosion Meridol mouthwash should not be prescribed for patients wearing Ti or FeCrNi-based orthodontic brackets.

PMID: 16049037 [PubMed - indexed for MEDLINE]

A subjective comparison of two lingual bracket systems.

Eur J Orthod. 2005 Aug;27(4):420-6

Authors: Stamm T, Hohoff A, Ehmer U

The purpose of this prospective, longitudinal study was to compare the influence of two lingual bracket systems on subjective oral comfort, speech, mastication and oral hygiene. Forty-two native speakers of standard German (32 females, 10 males; mean age 27.1 years, standard deviation 12.2) were enrolled and completed a standardized questionnaire directly before insertion of lingual brackets (T0), within 24 hours of bond-up (T1) and 3 months (+/- 1 week) later (T2). Eighteen of the patients were treated with prefabricated brackets (Ormco, seventh generation) (PB group) and 24 with customized brackets (Incognito) (CB group).While no significant intergroup differences were recorded at any of the times with respect to tongue position, conversation pattern, swallowing or oral hygiene, the CB group experienced significantly fewer tongue space restrictions, speech disturbances and impairments in chewing and biting than the PB group at T1 and T2. At T2, pressure sores, reddening or lesions to the tongue were recorded significantly less often in the CB group than in the PB group.This enhanced patient comfort in the CB group was attributed to the smaller dimensions of the customized brackets. This aspect could play a role in attracting more patients to lingual orthodontics in the future. Information given to the patient on the duration and extent of the restrictions associated with lingual orthodontics must be differentiated according to the bracket system used.

PMID: 16043479 [PubMed - indexed for MEDLINE]

Enamel loss at bond-up, debond and clean-up following the use of a conventional light-cured composite and a resin-modified glass polyalkenoate cement.

Eur J Orthod. 2005 Aug;27(4):413-9

Authors: Ireland AJ, Hosein I, Sherriff M

The aim of this study was to determine whether there was any difference in the degree of enamel loss at bond-up, debond and enamel clean-up when two different adhesive systems were tested and with four different methods of enamel clean-up. The adhesive systems were 37 per cent o-phosphoric acid with Transbond XT (group 1) and 10 per cent poly(acrylic acid) conditioner with Fuji Ortho LC (group 2). Using flattened enamel specimens, enamel loss at each stage was determined using a planer surfometer. These stages were: prior to treatment, at pumice prophylaxis, following enamel etching or conditioning and following enamel clean-up. The four clean-up methods were a high-speed tungsten carbide bur, a slow-speed tungsten carbide bur, an ultrasonic scaler and debanding pliers.The results, analysed using non-parametric tests, demonstrated that significantly more enamel loss occurred following the use of 37 per cent o-phosphoric acid than poly(acrylic acid) conditioner (P = 0.001). At debond and prior to clean-up, more adhesive remained on the enamel surface in group 1 than in group 2 (P = 0.005). During the subsequent enamel clean-up and with both adhesive systems, the least enamel loss occurred following the use of the slow-speed tungsten carbide bur and the greatest loss was seen with the ultrasonic scaler or high-speed tungsten carbide bur.Overall, the lowest enamel loss was observed with the poly(acrylic acid) conditioner and Fuji Ortho LC system (group 2) and where enamel clean-up was performed using the slow-speed tungsten carbide bur.

PMID: 16043478 [PubMed - indexed for MEDLINE]

Tensile bond strength of brackets after antioxidant treatment on bleached teeth.

Eur J Orthod. 2005 Oct;27(5):466-71

Authors: Bulut H, Kaya AD, Turkun M

Various studies have reported a significant reduction in tensile bond strength of brackets when bonding is carried out immediately after bleaching. The purpose of this investigation was to determine the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with composite resin to human enamel after bleaching with carbamide peroxide (CP). A total of 80 extracted premolar teeth were randomly divided into three bleaching groups of 10 per cent CP and an unbleached control group. The specimens in group 1 were bonded immediately after bleaching; group 2 were stored in an artificial saliva solution for 7 days after bleaching; group 3 were treated with 10 per cent sodium ascorbate, immediately before bonding, whereas the unbleached specimens in group 4 had no treatment before bonding. Tensile bond strengths were established in MPa. To evaluate the amount of resin left on the enamel surfaces after debonding, the adhesive remnant index (ARI) scores were used. The tensile bond strength data were analyzed with the Kruskal-Wallis test and pairwise comparisons were made by the Mann-Whitney U test at a significance level of P < 0.05. The brackets bonded immediately after bleaching revealed significantly lower tensile bond strengths than those of unbleached enamel (P = 0.000). No statistically significant differences in tensile bond strength were noted when the delayed-bonding (P = 6.000) and antioxidant-treated (P = 0.2757) groups were compared with the control group. The antioxidant treatment immediately after bleaching was effective in reversing the tensile bond strength of brackets.

PMID: 16043470 [PubMed - indexed for MEDLINE]

An in vitro comparison of the shear bond strength of a resin-reinforced glass ionomer cement and a composite adhesive for bonding orthodontic brackets.

Eur J Orthod. 2005 Oct;27(5):477-83

Authors: Movahhed HZ, Ogaard B, Syverud M

The shear bond strength (SBS) of a light-cured, resin-reinforced glass ionomer and a composite adhesive in combination with a self-etching primer was compared after different setting times to evaluate when orthodontic wires could be placed. Additionally, the fracture site after debonding was assessed using the Adhesive Remnant Index (ARI). Eighty freshly extracted human premolars were used. Twenty teeth were randomly assigned to each of four groups: (1) brackets bonded with Transbond XT with a Transbond Plus etching primer and debonded within 5 minutes; (2) brackets bonded with Fuji Ortho LC and debonded within 5 minutes; (3) brackets bonded as for group 1 and debonded within 15 minutes; (4) brackets bonded as for group 2 and debonded within 15 minutes. The SBS of each sample was determined with an Instron machine. The mean SBS were, respectively: (1) 8.8 +/- 2 MPa; (2) 6.6 +/- 2.5 MPa; (3) 11 +/- 1.6 MPa and (4) 9.6 +/- 1.6 MPa. Interpolating the cumulative fracture probability by means of a Weibull analysis, the 10 per cent probabilities of fracture for the groups were found to be attained for shear stresses of 6.1, 3.1, 8.3 and 7.1 MPa, respectively. Chi-square testing of the ARI scores revealed that the nature of the remnant did not vary significantly with time, but the type of bonding material could generally be distinguished in leaving more or less than 10 per cent of bonding material on the tooth. After debonding, the Transbond system was likely to leave adhesive on at least 10 per cent of the bonded area of the tooth. The present findings indicate that brackets bonded with either Transbond XT in combination with Transbond Plus etching primer and Fuji Ortho LC had adequate bond strength at 5 minutes and were even stronger 15 minutes after initial bonding.

PMID: 16043469 [PubMed - indexed for MEDLINE]

Aesthetic orthodontic brackets.

J Orthod. 2005 Jun;32(2):146-63

Authors: Russell JS

Due to an increasing demand for superior aesthetics during fixed appliance treatment, the use of aesthetic brackets has grown in popularity over recent years. Although often requested by patients, aesthetic brackets are not without their disadvantages. This article presents the currently available plastic and ceramic brackets and discusses the potential problems associated with each. Recent advances, introduced by manufacturers in an attempt to overcome their clinical disadvantages, are described.

PMID: 15994990 [PubMed - indexed for MEDLINE]

TN3-a bracket positioning instrument.

J Orthod. 2005 Jun;32(2):98-9

Authors: Samuels RH

PMID: 15994983 [PubMed - indexed for MEDLINE]

Recolonization of mutans steptococci on teeth with orthodontic appliances after antimicrobial therapy.

Eur J Orthod. 2005 Oct;27(5):489-93

Authors: Attin R, Thon C, Schlagenhauf U, Werner C, Wiegand A, Hannig C, Attin T

The aim of the present study was to compare the recolonization pattern of mutans streptococci on densely colonized teeth with and without fixed orthodontic appliances after treatment with a 40 per cent chlorhexidine (CHX) varnish (EC 40, Explore). Healthy subjects free of carious lesions requiring fixed orthodontic appliance treatment but with high bacterial mutans streptococci saliva counts were recruited (n = 10). For baseline registration, plaque from buccal sites was sampled and cultivated on Dentocult strips. Following professional tooth cleaning, CHX varnish was applied to all teeth for 8 minutes. Subsequently, orthodontic brackets and bands were inserted in either the upper or lower arch. Eight weeks after varnish application the degree of recolonization with mutans streptococci was reassessed on the buccal sites. Statistical analysis showed that recolonization with mutans streptococci was significantly higher (P < 0.05) on teeth with orthodontic appliances. The results indicate that the use of fixed orthodontic appliances creates artificial environments suitable for the proliferation of mutans streptococci after CHX varnish suppression.

PMID: 15961573 [PubMed - indexed for MEDLINE]

Light curing time reduction: in vitro evaluation of new intensive light-emitting diode curing units.

Eur J Orthod. 2005 Aug;27(4):408-12

Authors: Mavropoulos A, Staudt CB, Kiliaridis S, Krejci I

The aim of the present in vitro study was to establish the minimum necessary curing time to bond stainless steel brackets (Mini Diamond Twin) using new, intensive, light-emitting diode (LED) curing units. Seventy-five bovine primary incisors were divided into five equal groups. A standard light curing adhesive (Transbond XT) was used to bond the stainless steel brackets using different lamps and curing times. Two groups were bonded using an intensive LED curing lamp (Ortholux LED) for 5 and 10 seconds. Two more groups were bonded using another intensive LED curing device (Ultra-Lume LED 5) also for 5 and 10 seconds. Finally, a high-output halogen lamp (Optilux 501) was used for 40 seconds to bond the final group, which served as a positive control. All teeth were fixed in hard acrylic and stored for 24 hours in water at 37 degrees C. Shear bond strength (SBS) was measured using an Instron testing machine. Weibull distribution and analysis of variance were used to test for significant differences.The SBS values obtained were significantly different between groups (P < 0.001). When used for 10 seconds, the intensive LED curing units achieved sufficient SBS, comparable with the control. In contrast, 5 seconds resulted in significantly lower SBS. The adhesive remnant index (ARI) was not significantly affected.A curing time of 10 seconds was found to be sufficient to bond metallic brackets to incisors using intensive LED curing units. These new, comparatively inexpensive, curing lamps seem to be an advantageous alternative to conventional halogen lamps for bonding orthodontic brackets.

PMID: 15961571 [PubMed - indexed for MEDLINE]

Archwire seating forces produced by different ligation methods and their effect on frictional resistance.

Eur J Orthod. 2005 Jun;27(3):302-8

Authors: Khambay B, Millett D, McHugh S

The aims of this study were to determine the mean tensile force of four different elastomeric modules, the archwire seating force of different ligation methods, and its effect on frictional resistance.To determine the mean tensile force, each elastomeric module (purple, grey, Alastik, and SuperSlick) was extended by 5 mm using two hooks attached to a load cell using a Nene M3000 testing machine. To assess the median archwire seating force, a maxillary premolar bracket (3M Unitek) was welded to a sheet of stainless steel (SS) and glued to a Perspex block. The bracket base was removed and the cut continued into the Perspex below. A length of test wire was taken and bent to form a "U" shape, with the middle portion 20 mm in length. The free ends of the wire were secured to the load cell of the Nene testing machine. Two wire sizes were tested, 0.017 x 0.025 and 0.019 x 0.025 inch SS. The load cell was activated and the force with which the wire was displaced into the slot by the ligation method was measured. Four types of elastomeric module were tested together with a pre-formed 0.09 inch SS ligature. The experimental method used to determine the mean frictional force of each module and wire size was carried out using a method described previously.Statistically significant differences existed in the mean tensile forces and median archwire seating forces between the elastomeric modules. Grey modules with either size wire produced the lowest median archwire seating force, whereas SS ligatures produced the highest forces. SS ligatures with either wire produced the lowest mean frictional forces, whereas grey modules produced significantly higher mean frictional force (P < 0.01). The force with which the wire was seated into the bracket did not seem to be related to the subsequent amount of mean frictional force produced.

PMID: 15947232 [PubMed - indexed for MEDLINE]

Anterior tooth morphology and its effect on torque.

Eur J Orthod. 2005 Jun;27(3):258-62

Authors: van Loenen M, Degrieck J, De Pauw G, Dermaut L

This study was undertaken to determine the variation in crown-root angle (CRA) of the upper incisors and canines as well as the variation in their labial contour. In addition, the influence of the variability of the labial contour and of different bracket heights on torque was evaluated. Proximal radiographs were taken of 160 extracted maxillary teeth (81 incisors and 79 canines). They were digitized and analysed with Jasc Paint Shop Pro 7TM and Mathcad 2001 Professional. The incisal edge, the centre of the cemento-enamel junction (CEJ), and the root apex were digitized to define the crown and root long axis. For all teeth the CRA was measured. At several heights of the labial surface a tangent was determined, enabling measurement of the inclination of the labial surface.The CRA had great variability, ranging from 167 to 195 degrees for the canines (mean value 183 degrees) and from 171 to 195 degrees for the incisors (average 184 degrees). The mean inclinations of the labial surfaces for the incisors varied greatly. Between 4 and 4.5 mm from the incisal edge the standard deviations (SD) were the smallest and between 2 and 4.5 mm from the incisal edge the labial surface angle differed by approximately 10 degrees. For the canines the mean inclinations of the buccal surface also varied. This angle differed by around 10 degrees between 2 and 4.5 mm from the incisal edge, but the SD were much larger than for the incisors.It can be concluded that placement of a bracket on a tooth at varying heights, still within a clinically acceptable range, results in important differences in the amount of root torque.

PMID: 15947225 [PubMed - indexed for MEDLINE]

An investigation into the use of two polyacid-modified composite resins (compomers) and a resin-modified glass poly(alkenoate) cement used to retain orthodontic bands.

Eur J Orthod. 2005 Jun;27(3):245-51

Authors: Williams PH, Sherriff M, Ireland AJ

The aim of this investigation was to determine the effectiveness of a conventional glass poly(alkenoate) cement (Intact) and newer polyacid-modified composite resin cements (Transbond Plus and Ultra Band-Lok) to retain orthodontic bands.In the in vitro part of this study, stainless steel bands were cemented to 240 extracted third molar teeth in three test groups comprising Intact, Transbond Plus and Ultra Band-Lok. The force to deband (N) for all three cements was recorded using an Instron universal testing machine after the following observation periods: 20 minutes and 3, 6 and 12 months. The results indicated that all three cements increased their median force to deband after 12 months. Of the two compomers, Transbondtrade mark Plus demonstrated the highest median force to deband at all four time intervals.In the in vivo part of the study, 30 patients participated in a randomized cross-mouth clinical trial where the molar bands were cemented in place using either Intact or Transbond Plus. Ultra Band-Lok was not used in the clinical part of the study. The results showed there to be no clinically significant difference in band failure rates between the two cements. When patients were asked to score each for taste, there was a significant difference, with the glass poly(alkenoate) cement (Intact) being more acceptable than the polyacid-modified composite Transbond Plus (P < 0.001).No significant differences were observed in the in vitro median force to deband or in vivo band failure rates between the glass poly(alkenoate) cement and the polyacid-modified composite resins. The choice of cementing agent can therefore be made on patient factors, e.g. taste, or operator factors, e.g. ease of handling, cost and shelf life.

PMID: 15947223 [PubMed - indexed for MEDLINE]

A stainless steel bracket for orthodontic application.

Eur J Orthod. 2005 Jun;27(3):237-44

Authors: Oh KT, Choo SU, Kim KM, Kim KN

Aesthetics has become an essential element when choosing orthodontic fixed appliances. Most metallic brackets used in orthodontic therapy are made from stainless steel (SS) with the appropriate physical properties and good corrosion resistance, and are available as types 304, 316 and 17-4 PH SS. However, localized corrosion of these materials can frequently occur in the oral environment. This study was undertaken to evaluate the accuracy of sizing, microstructure, hardness, corrosion resistance, frictional resistance and cytotoxicity of commercially available Mini-diamond (S17400), Archist (S30403) and experimentally manufactured SR-50A (S32050) brackets.The size accuracy of Mini-diamond was the highest at all locations except for the external horizontal width of the tie wing (P < 0.05). Micrographs of the Mini-diamond and Archist showed precipitates in the grains and around their boundaries. SR-50A showed the only austenitic phase and the highest polarization resistance of the tested samples. SR-50A also had the highest corrosion resistance [SR-50A, Mini-diamond and Archist were 0.9 x 10(-3), 3.7 x 10(-3), and 7.4 x 10(-3) mm per year (mpy), respectively], in the artificial saliva. The frictional force of SR-50A decreased over time, but that of Mini-diamond and Archist increased. Therefore, SR-50A is believed to have better frictional properties to orthodontic wire than Mini-diamond and Archist. Cytotoxic results showed that the response index of SR-50A was 0/1 (mild), Mini-diamond 1/1 (mild+), and Archist 1/2 (mild+). SR-50A showed greater biocompatibility than either Mini-diamond or Archist.It is concluded that the SR-50A bracket has good frictional property, corrosion resistance and biocompatibility with a lower probability of allergic reaction, compared with conventionally used SS brackets.

PMID: 15947222 [PubMed - indexed for MEDLINE]

Office reconditioning of stainless steel orthodontic attachments.

Eur J Orthod. 2005 Jun;27(3):231-6

Authors: Quick AN, Harris AM, Joseph VP

An investigation was conducted to determine a simple, effective method for reconditioning stainless steel orthodontic attachments in the orthodontic office. In total, 100 new brackets were bonded to premolar teeth, then debonded and the bond strength recorded as a control for the reconditioning process. The debonded brackets were divided into six groups and each group reconditioned using different techniques as follows: attachments in four groups were flamed and then either (1) sandblasted, (2) ultrasonically cleaned, (3) ultrasonically cleaned followed by silane treatment, (4) rebonded without further treatment. Of the two remaining groups, one was sandblasted, while the brackets in the other were roughened with a greenstone. The brackets were rebonded to the premolar teeth after the enamel surfaces had been re-prepared, and their bond strengths measured.The results indicated that sandblasting was the most effective in removing composite without a significant change in bond strength compared with new attachments. Silane application did not improve the bond strength values of flamed and ultrasonically cleaned brackets. Attachments that had only been flamed had the lowest bond strength, followed by those that had been roughened with a greenstone.

PMID: 15947221 [PubMed - indexed for MEDLINE]

The variable anchorage straight wire technique compared with the straight wire technique in deep overbite correction.

Eur J Orthod. 2005 Apr;27(2):180-5

Authors: Banaie F, Parikakis K, Moberg S, Hellsing E

The aim of this retrospective study was to compare the treatment results and the number of required treatment appointments between the variable anchorage straight wire technique (VAST) and the straight wire (SW) technique. The subjects were 53 Caucasian patients of both sexes (25 males and 28 females, mean age 13.5 years at the start of treatment), with an overjet > or = 4 mm and an overbite > or = 3 mm. The patients were divided into four groups, VAST (n = 31) or SW (n = 22), extraction or non-extraction, and were treated by the same orthodontist. Variables from two lateral cephalograms obtained before and at the completion of active treatment, and the number of scheduled appointments were compared between the two techniques.The main difference between the two techniques was the bracket design. With the VAST, the bracket allowed both tipping and parallel movements with the possibility to combine double archwires. Due to the influence of the Begg technique, no extra-oral traction was needed in the VAST groups and Class II elastics were used at the start of treatment.Both techniques seemed to produce equal treatment results. However, in this study, it was shown that in deep overbite correction, the VAST required fewer scheduled appointments than the SW technique.

PMID: 15817626 [PubMed - indexed for MEDLINE]

Chlorhexidine-modified glass ionomer for band cementation? An in vitro study.

J Orthod. 2005 Mar;32(1):26

Authors: Ireland T

PMID: 15816073 [PubMed - indexed for MEDLINE]

Chlorhexidine-modified glass ionomer for band cementation? An in vitro study.

J Orthod. 2005 Mar;32(1):36-42

Authors: Millett DT, Doubleday B, Alatsaris M, Love J, Wood D, Luther F, Devine D

OBJECTIVE: To compare the mean retentive strength, predominant site of band failure, amount of cement remaining on the tooth at deband and survival time of orthodontic micro-etched bands cemented with chlorhexidine-modified (CHXGIC) or conventional glass ionomer cement (GIC). DESIGN: In vitro study. SETTING: Dental Materials Laboratory. MATERIALS AND METHODS: One-hundred-and-twenty intact, caries-free third molars were collected from patients attending for third molar surgery. These were stored for 3 months in distilled water and decontaminated in 0.5% chloramine. To assess retentive strength, 80 teeth were randomly selected and 40 were banded with each cement. Testing was undertaken using a Nene M3000 testing machine at a cross-head speed of 1 mm/min. Following debanding, the predominant site of failure was recorded as cement-enamel or cement-band interface. The amount of cement remaining on the tooth surface following deband was assessed and coded. Survival time for another 40 banded specimens, 20 cemented with each cement, was assessed following application of mechanical stress in a ball mill. MAIN OUTCOME MEASURES: Retentive strength, predominant site of failure, amount of cement remaining on the tooth surface, survival time. RESULTS: Mean retentive strength for bands cemented with CHXGIC (0.32 MPa, SD 0.09) or GIC (0.28 MPa, SD 0.07) did not differ significantly (p=0.05). All bands failed at the enamel-cement interface. There was no significant difference in the amount of cement remaining on the tooth surface after deband for each cement type (p=0.23). The mean survival time of bands cemented with CHXGIC or GIC was 7.0 and 6.4 hours, respectively (p=0.23). CONCLUSIONS: There was no significant difference in mean retentive strength, amount of cement remaining on the tooth after deband or mean survival time of bands cemented with CHXGIC or GIC. Bands cemented with either cement failed predominantly at the enamel-cement interface. The results suggest that CHXGIC may have comparable clinical performance to GIC for band cementation.

PMID: 15784942 [PubMed - indexed for MEDLINE]

An in vivo study to compare a plasma arc light and a conventional quartz halogen curing light in orthodontic bonding.

Eur J Orthod. 2004 Dec;26(6):573-7

Authors: Pettemerides AP, Sherriff M, Ireland AJ

The purpose of this study was to compare the effectiveness of a plasma arc lamp with a conventional tungsten quartz halogen lamp in orthodontic bonding. Twenty consecutive patients had their brackets bonded either with Transbond XT (n = 10) or Fuji Ortho LC (n = 10). In total, 352 teeth were bonded, 176 in each group. Using a randomized cross-mouth control study design, where diagonally opposite quadrants were assigned a particular treatment, the bonds were then either cured with the control light, namely a halogen lamp, or a plasma arc lamp. The halogen light was used for 20 seconds per tooth and the plasma arc lamp for 3 seconds per tooth. The measurement parameter used was bond failure and the patients were monitored for a period of 6 months following initial bond placement.In the Transbond XT group, the proportion of bond failures was 3.41 per cent for both the halogen and the plasma arc lamp. For the Fuji Ortho LC group, the proportions were 11.4 and 10.2 per cent, respectively. No difference was observed with respect to in-service bond failure proportions between bonds cured with the plasma arc or the conventional halogen lamp, irrespective of the bonding agent. Use of the plasma arc lamp could therefore lead to considerable savings in clinical time. However, this must be weighed against the increased purchase price of the plasma arc lamp.

PMID: 15650065 [PubMed - indexed for MEDLINE]

Six and 12 months' evaluation of a self-etching primer versus two-stage etch and prime for orthodontic bonding: a randomized clinical trial.

Eur J Orthod. 2004 Dec;26(6):565-71

Authors: Aljubouri YD, Millett DT, Gilmour WH

The aim of the study was to compare the mean clinical chair-side time required for bracket bonding and the mean bond failure rate at 6 and 12 months of stainless steel brackets with a micro-etched base bonded with a light-cured composite using a self-etching primer (SEP) or a two-stage etch and prime system.Fifty-one subjects who required upper and/or lower pre-adjusted edgewise fixed appliances were recruited in a single centre randomized clinical trial. The trial was a single-blind design, involving a within-patient comparison of the two bonding systems with each patient randomly allocated the two bonding systems for each side of the mouth (all teeth except molars). The two bonding techniques used were standardized throughout the trial and all bracket bonding was performed by a single operator. Bonding time was recorded using a digital timer. The bond failure rate of a strictly paired sample was recorded at 6 and 12 months for each patient.The mean bracket bonding time per patient with the SEP was significantly less than that with the two-stage bonding system (mean difference 24.9 seconds; 95 per cent confidence interval 22.1-27.7 seconds; paired t-test P < 0.001). The overall bond failure rates at 6 and 12 months with the SEP were 0.8 and 1.6 per cent, respectively, and for the two-stage etch and prime 1.1 and 3.1 per cent, respectively. At 6 months, the mean bond failure rate per patient with the SEP was 0.81 per cent and with the two-stage bonding system 0.96 per cent (P = 0.87; Wilcoxon signed rank test). At 12 months, the mean bond failure rate with the SEP per patient was 1.54 per cent and with the two-stage bonding system 2.78 per cent (P = 0.33; Wilcoxon signed rank test).The mean bracket bonding time with the SEP per patient was significantly shorter than that of the two-stage bonding system (P < 0.001). The difference between the overall bond failure rate and the mean bond failure rate per patient for the two bonding systems was not statistically nor clinically significant at 6 and 12 months (P = 1.00 and P = 0.125, respectively; McNemar's test).

PMID: 15650064 [PubMed - indexed for MEDLINE]

An ex vivo evaluation of resin-modified glass polyalkenoates and polyacid-modified composite resins as orthodontic band cements.

J Orthod. 2004 Dec;31(4):323-8; discussion 301-2

Authors: Knox J, Chye KY, Durning P

OBJECTIVES: The objective of this ex vivo study was to assess the use of resin-modified glass polyalkenoates and polyacid-modified composite resins, as orthodontic band cements. MATERIALS AND METHOD: Plain stainless steel bands were cemented to 350 human extracted third molar teeth using 1 of 7 different cements. Following complete cement cure, half of each sample group was exposed to mechanical stress in a ball mill. Stressed and unstressed samples were tested in tension and the stress at which initial cement failure recorded. The mode of failure was recorded using an adhesive remnant evaluation. RESULTS: The mean band retention stresses offered by the cements studied ranged from 0.96 to 1.56 MPa. Fuji Ortho provided the highest mean band retention stress in "stressed" (1.56 MPa) and "unstressed" (1.45 MPa) states. Exposure to mechanical stress did not appear to significantly influence band retention or mode of cement failure for most cements. Fuji Ortho cement recorded the highest Weibull modulus for all cements tested. Virtually all samples failed at either the cement/enamel or cement band interface. CONCLUSIONS: Significant differences in band displacement stress values and mode of failure were demonstrated between the cements studied. However, generic comparisons were difficult to make.

PMID: 15608348 [PubMed - indexed for MEDLINE]

The effects of argon laser curing of a resin adhesive on bracket retention and enamel decalcification: a prospective clinical trial.

Eur J Orthod. 2004 Oct;26(5):553-60

Authors: Elaut J, Wehrbein H

A prospective clinical trial was carried out to compare argon laser-curing of a traditional light-activated composite resin with conventional visible light-curing in terms of bond failure rate and incidence of enamel decalcification. Forty-five patients with a total of 742 metal brackets bonded to the upper and/or lower teeth in a modified split-mouth design participated in the study. The adhesive (Transbond XT) on the control teeth was cured by conventional visible light for 40 seconds, and the experimental teeth were exposed to 10 seconds of 250 mW argon laser irradiation. The patients were monitored for a period of 14 months. Intraoral photographic slides of the maxillary anterior teeth (212 in total) were taken at the beginning of treatment, after 12 months of treatment, following application of a plaque disclosing agent, and at the end of the observation period, following temporary debonding. Seven dentists used standardized rating systems to evaluate decalcification and plaque accumulation. The results of this study indicated that there were no significant differences between curing methods for the incidence of decalcification and plaque accumulation. However, the 10 second argon laser-curing method showed a statistically lower bond failure rate (2.4 per cent, P < 0.05) than the 40 second conventional visible light-curing method (5.7 per cent). It is concluded that the use of argon laser curing is superior to that of conventional light-curing with respect to bond failure and chairside time. However, the incidence of decalcification seems to be similar.

PMID: 15536845 [PubMed - indexed for MEDLINE]

A comparative in vitro study of the strength of directly bonded brackets using different curing techniques.

Eur J Orthod. 2004 Oct;26(5):535-44

Authors: Wendl B, Droschl H

The aim of this study was to compare, by shear testing, the bond strengths after 1 and 24 hours of a light-cured resin (Enlight) and a light-cured glass ionomer cement GIC (Fuji Ortho LC) using various polymerization lamps (halogen, high performance halogen, xenon, and diode) for the direct bonding of brackets. The self-curing resin (Concise) was used as the control. The analysis was carried out using the SPSS program. For group comparison purposes, the single factor variance analysis (ANOVA) and the post-hoc test (Tukey's HSD) were used. The level of significance was established at P < 0.05. When comparing two mean values the t-test for independent random samples was employed. All polymerization lamps achieved the minimum bond strength of 5-8 MPa. With Enlight LV, bond strength was dependent on curing time (the halogen lamp achieved the highest bond strength of 10.0 MPa, P < 0.001, with a curing time of 40 seconds. The other lamps showed similar results) and on the mode of cure (the highest bond strength values were achieved by four-sided curing, P= 0.04). Fuji Ortho LC, on the other hand, was independent of the duration of light curing and the type of lamp used. The bond strengths of the resin-modified glass ionomer cement (RMGIC) were similar to or somewhat higher than those achieved with light-cured composite resin (P = 0.039) when lamps with short polymerization times were used, but were significantly lower (P< 0.001) when compared with the self-curing composite adhesive. After 24 hours, the bond strengths of all adhesives showed a significant increase: Enlight 19 per cent, Fuji Ortho LC 6.6 per cent, Concise 16 per cent. Bond failure occurred for Enlight at the bracket-composite resin adhesive interface in 90 per cent and with Concise in 57 per cent. However, Fuji Ortho LC showed far more cohesive and mixed failures, indicating an improved bond between bracket and cement.

PMID: 15536843 [PubMed - indexed for MEDLINE]

Comparison of initial shear bond strengths of plastic and metal brackets.

Eur J Orthod. 2004 Oct;26(5):531-4

Authors: Liu JK, Chuang SF, Chang CY, Pan YJ

The aims of this study were to compare initial and 24 hour shear bond strengths of plastic brackets with a mechanical base (Spirit MB) and metal brackets, using two different adhesives (System 1+ and Enlight), and to examine the modes of failure after debonding. Eighty extracted human premolars were used. After bonding, shear bond strengths in half the sample were tested within 30 minutes. The remaining 50 per cent were placed in a 37 degrees C distilled water bath for 24 hours before testing. The results showed that the effects of the two adhesives and the interaction of the two time intervals and the two bracket types on shear bond strength were significantly different (P < 0.05 and P < 0.0001, respectively). Six of the 10 groups were found to have less than 50 per cent of the adhesive remaining on the tooth surface after debonding in the 24 hour metal bracket-System 1+ group, but most specimens in the other seven groups had more than 50 per cent of the adhesive left. It is concluded that System 1+ cannot provide sufficient initial bond strengthfor Spirit MB and may increase the risk of enamel fracture for metal brackets.

PMID: 15536842 [PubMed - indexed for MEDLINE]

How to effectively use a 2 x 4 appliance.

J Orthod. 2004 Sep;31(3):248-58

Authors: Dowsing P, Sandler PJ

A mixed dentition treatment can efficiently and effectively be provided using a 2 x 4 appliance. The indications for early treatment are discussed and advantages of fixed appliances over traditionally used removable appliances illustrated using four case reports.

PMID: 15489369 [PubMed - indexed for MEDLINE]