In vitro study of force decay of latex and non-latex orthodontic elastics.

The aim of this study was to evaluate the force decay of two brands of orthodontic elastics, both offering latex and non-latex products. Samples were subjected to continuous stretching, measuring force at 5 seconds, 8 hours, and 24 hours in both dry and wet conditions. Five hundred samples were used, GAC® and Lancer® 0.25 inch and 4 oz, divided into testing sample sizes of n = 25 per group. For the dry test, elastics were kept stretched to three times their internal diameter for 5 seconds (initial force), 8 hours, and 24 hours; for the wet test, they were stretched for 8 and 24 hours. Both brands showed initial forces significantly greater than those specified by the manufacturers (P < 0.05). Comparing wet/dry conditions, there was a greater force loss in the wet medium than the dry. As for elastic composition (latex or non-latex), the only significant difference found was between Lancer elastics with and without latex in dry conditions, force loss being greater for latex-free elastics. Comparing brands, there was greater force loss with GAC than with Lancer. Comparing elastic force at the eight-hour mark and the twenty-four hour mark to the initial force (only in wet conditions), GAC latex and non-latex and Lancer latex elastics showed significantly less force at eight and twenty four hours than initially. On the other hand, Lancer non-latex was the only type of elastics that did not show a significant decrease in its initial elastic characteristics at eight hours in wet conditions. Nevertheless, Lancer non-latex did show significantly less force in wet conditions at twenty four-hours than the forces observed initially and at eight-hours.

The effects of two soft drinks on bond strength, bracket microleakage, and adhesive remnant on intact and sealed enamel.

The purpose of this study was to evaluate the effects of Coca-Cola and Schweppes Limón on bond strength, adhesive remnant, and microleakage beneath brackets. One hundred and twenty upper central incisor brackets were bonded to bovine incisors and divided into three groups: (1) Control, (2) Coca-Cola, and (3) Schweppes Limón. The teeth were submerged in the drinks three times a day for 15 minutes over a 15 day period. Shear bond strength (SBS) was measured with a universal testing machine, and adhesive remnant evaluated using image analysis equipment. Microleakage at the enamel-adhesive and adhesive-bracket interfaces was determined using methylene blue. One hundred and eight teeth were used for scanning electron microscopy to determine the effect of the drinks on intact and sealed enamel. SBS and adhesive remnant data were analysed using the Kruskal-Wallis test (P < 0.05) and microleakage using the Kruskal-Wallis and Mann-Whitney tests applying Bonferroni correction (P < 0.017). No significant differences were found in SBS and adhesive remnant between the groups (P > 0.05). Microleakage at the enamel-adhesive interface for groups 2 and 3 was significantly greater than for group 1 (P < 0.017). At the adhesive-bracket interface, microleakage was significantly greater in group 2 than in group 1 (P < 0.017) while microleakage in group 3 did not differ significantly from either group 1 or 2 (P < 0.017). The drinks produced enamel erosion, loss of adhesive and microleakage. Coca-Cola and Schweppes Limón did not affect the SBS of brackets or the adhesive remnant.

Melatonin stimulates the growth of new bone around implants in the tibia of rabbits.

This study evaluated the effect of the topical application of melatonin in accelerating bone formation associated with implants 2 months after their application to the tibiae of rabbits. Twenty New Zealand rabbits were used. Twenty implants treated with melatonin and 20 control implants without melatonin were placed in the proximal metaphyseal area of each tibia. Studies of new bone formation were subsequently made at 15, 30, 45 and 60 days. Cortical width and cortical length of new bone formation were measured. Following implantation, an anteroposterior and lateral radiologic study was carried out. Collected samples were sectioned at 5 µm and stained using hematoxylin-eosin, Masson's trichromic and Gordon-Switt reticulin stains. After a 60 day treatment period, melatonin increased the length of cortical bone (95.13±0.42%) versus that around control implants (62.91±1.45%). Related to the perimeter of cortical bone of the tibiae, melatonin induced new bone 88.35±1.56% versus 60.20±1.67% in the control implants. Melatonin regenerated the width and length of cortical bone around implants in tibiae of rabbits more quickly than around control implants without the addition of melatonin.

Effect of saliva contamination on bracket failure with a self-etching primer: a prospective controlled clinical trial.

INTRODUCTION: The aim of this study was to evaluate in vivo the effect of saliva contamination at different stages of the bonding procedure on the bond failure rate and the adhesive remaining on teeth after debonding brackets bonded with a hydrophilic self-etching primer (Transbond Plus self-etching primer [TSEP], 3M Unitek, Monrovia, Calif). METHODS: This was a prospective controlled clinical trial. The sample consisted of 46 patients with similar treatment plans and mechanotherapies. Stainless steel brackets (n = 531) were bonded with TSEP. The patients were divided into 2 groups: contamination with saliva before TSEP application and contamination with saliva after TSEP application. In both groups, saliva was applied in a split-mouth design. Diagonally opposite quadrants were allocated to either the contaminated group (contamination before [153 teeth] or after [115 teeth] TSEP application) or to the uncontaminated control group (263 teeth). Recording of failed brackets involved only first-time failures, and the observation period was a minimum of 6 months. RESULTS: The chi-squared test showed no significant differences (P = 0.11) in bracket failures between the groups. Kaplan-Meier survival analysis detected no significant differences in the survival rates between the 3 groups (P = 0.51). Most bond failures occurred during the first 3 months. In all 3 groups, the adhesive remaining on teeth after debonding tended to be less than half. CONCLUSIONS: These findings suggest that saliva contamination before or after application of self-etching primer does not increase the clinical risk of bond failure.

The in vitro effect of repeated bonding on the shear bond strength with different enamel conditioning procedures.

The aims of this study were to evaluate the effect on shear bond strength (SBS), adhesive remnant, and enamel surface of repeated bonding of new brackets on the same tooth using different methods of enamel conditioning. One hundred and thirty-five bovine incisors were used. Brackets were bonded to enamel using one of the following conditioning procedures: (1) 37 per cent phosphoric acid, (2) 37 per cent phosphoric acid (prior to first bond but not for further bonds), (3) Transbond Plus Self Etching Primer (TSEP), and (4) non-rinse-conditioner (NRC). Brackets were sequentially bonded and debonded three times following the same conditioning procedure with the exception of group 2 where 37 per cent phosphoric acid was not reapplied prior to the second and third bonding sequences. SBS and adhesive remnant were evaluated for each debond. Scanning electron microscopy observations were made for each conditioning sequence. Statistical analysis was undertaken using ANOVA, Mann-Whitney, and Kruskal-Wallis tests. Bond strength and adhesive remnant values were similar across the four groups for the first and second bonding sequences. At the third sequence, SBS was significantly less (P < 0.008) for group 2 (5.71 +/- 1.56 MPa) than for group 1 (9.42 +/- 2.75 MPa) and the adhesive remnant was significantly lower (P < 0.008) for group 2 (6.93% +/- 3.34) than for the other groups (group 1: 16.95 +/- 4.99 per cent, group 3: 14.40 +/- 5.11 per cent, and group 4: 14.60 +/- 5.33 per cent). When comparing the SBS and adhesive remnant of the three bonding/debonding sequences within each group, both the SBS and adhesive remnant for group 2 (SBS: 5.71 +/- 1.56 MPa and adhesive remnant: 6.93 +/- 3.34%) at the third sequence were significantly less (P < 0.017) than at the first (SBS: 10.44 +/- 3.55 MPa and adhesive remnant: 13.81 +/- 5.59%) and second (SBS: 9.23 +/- 2.69 MPa and adhesive remnant: 15.32 +/- 6.85%) sequences. Enamel changes were similar across all groups. TSEP and NRC produced bonds that were similar to acid etching. When acid etching is used, it is possible to avoid etching for a second bond but not for following bonds.

Effect of water contamination on the shear bond strength of five orthodontic adhesives.

OBJECTIVES: To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. STUDY DESIGN: 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1) Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37 degrees C) and thermocycled. Brackets were debonded using a Universal testing machine (cross-head speed 1 mm/min). Failure sites were classified using a stereomicroscope. RESULTS: No significant differences in bond strength were detected between the adhesives under wet and dry conditions except for SmartBond, whose bond strength was significantly lower under dry conditions. For all the adhesives most bond failures were of mixed site location except for Smartbond, which failed at the adhesive-bracket interface. CONCLUSIONS: Under wet conditions the bonding capacity of the adhesives tested was similar than under dry conditions, with the exception of SmartBond which improved under wet conditions.

Evaluation of different flowable materials for bonding brackets.

PURPOSE: To compare the shear bond strength and the adhesive remnant on the tooth after debonding of brackets bonded with a traditional orthodontic resin (Transbond XT), a flowable composite (X-Flow), a flowable compomer (Dyract Flow) and a flowable giomer (Beautifil Flow). METHODS: 105 extracted human premolars were used. They were divided into four groups: (1) Transbond XT, (2) X-Flow, (3) Dyract Flow, and (4) Beautifil Flow. Shear bond strength was measured using a universal testing machine with a cross-head speed of 1 mm/minute. The adhesive remnant on the tooth after debonding was quantified using image analysis. RESULTS: No significant differences were found between the shear bond strengths of the different groups evaluated (P > 0.05). Transbond XT left significantly more adhesive on the tooth than the three flowable materials, and among the flowable materials, X-Flow left significantly less adhesive than Beautifil Flow (P < 0.008).

Microleakage beneath brackets bonded with flowable materials: effect of thermocycling.

The purpose of this study was to evaluate the effects of thermocycling on microleakage beneath brackets bonded with an orthodontic composite and different flowable materials. Brackets were bonded to 200 bovine incisors divided into five groups: (1) Transbond XT, (2) X-Flow, (3) Dyract-Flow, (4) Admira-Flow, and (5) Beautiful-Flow. Half the teeth in each group were thermocycled. The specimens were dyed with 1 per cent methylene blue for 24 hours to determine the percentage of microleakage into the enamel-adhesive and adhesive-bracket interfaces using image analysis equipment. Data were analysed using the Kruskal-Wallis and Mann-Whitney U-tests (P < 0.05), applying Bonferroni correction when required (P < 0.005). Without thermocycling, microleakage at the enamel-adhesive interface was significantly greater for Admira-Flow than for X-Flow (P < 0.005). At the adhesive-bracket interface, there were no significant differences (P > 0.005). After thermocycling, microleakage of Beautiful-Flow at the enamel-adhesive interface was significantly less than for the other materials tested (P < 0.005), while at the adhesive-bracket interface, Admira-Flow and X-Flow showed significantly more microleakage than Beautiful-Flow and Transbond XT (P < 0.005). Analysis of the effect of thermocycling on each material showed that microleakage increased significantly at the enamel-adhesive interface with Transbond XT (P < 0.05), decreased with Beautiful-Flow (P < 0.05), increased significantly at both interfaces with X-Flow, but not to a statistically significant level with Dyract-Flow and Admira-Flow (P > 0.05). The giomer, Beautiful-Flow, demonstrated the best performance after thermocycling, while composite resins and, in particular, the flowables showed a poorer performance.

Influence of an etchant and a desensitizer containing benzalkonium chloride on shear bond strength of brackets.

PURPOSE: To evaluate whether the application of an enamel etchant (Etch-37 BAC) and a desensitizer (PrepEze desensitizer) which contain the antibacterial agent benzalkonium chloride (BAC) affects the bond strength of the orthodontic resin Transbond XT. MATERIALS AND METHODS: Eighty-five extracted premolars were used. They were divided into four groups: 1. Transbond XT, 2. Etch-37 BAC/Transbond XT, 3. PrepEze/Transbond XT, 4. Etch-37 BAC/PrepEze/Transbond XT. Shear bond strength was measured using a universal testing machine with a crosshead speed of 1 mm/min. The adhesive remnant on the tooth after debonding was quantified using image analysis equipment. RESULTS: No significant differences were found in shear bond strength when Transbond XT was bonded with the conventional etchant or with Etch-37 BAC (p > 0.008). PrepEze decreased the shear bond strength and the amount of adhesive remnant on the tooth after debonding significantly (p < 0.008). The amount of adhesive remnant on the tooth surface diminished significantly when the enamel was etched with Etch-37 BAC (p < 0.008). CONCLUSIONS: The bond strength values obtained with the application of Etch-37 BAC are similar to those obtained with a conventional etchant. However, the application of PrepEze significantly decreased the bond strength of Transbond XT.

The use of a flowable ormocer for bonding brackets.

PURPOSE: To evaluate the effectiveness of the ormocer Admira Flow for bonding brackets. METHODS: 45 extracted human premolars were used. They were divided into two groups: (1) Brackets cemented with the traditional resin orthodontic bonding system Transbond XT, and (2) Brackets bonded with Admira Flow. Shear bond strength was measured with a universal testing machine with a cross-head speed of 1 mm/minute. The adhesive remnant on the tooth after debonding was quantified using image analysis equipment. RESULTS: No significant differences were observed in bond strength for Transbond XT and that of Admira Flow, nor were there significant differences in the quantity of adhesive remnant left on the teeth after debonding (P < 0.05).

Direct bonding with precoated brackets and self-etching primers.

PURPOSE: To evaluate the shear bond strength and the adhesive remnant on the tooth after the debonding of APC Plus precoated brackets, when conditioning the enamel with phosphoric acid and Transbond Plus Self Etching Primer (TSEP), in comparison with uncoated brackets bonded with Transbond XT. METHODS: The brackets were bonded to extracted premolars, which were divided into three groups: (1) Acid/Transbond XT, (2) Acid/ APC Plus and (3) TSEP/APC Plus. Shear bond strength was measured using a universal test machine. The crosshead speed was 1 mm/minute. The adhesive remnant on the tooth was quantified using an image analysis equipment. RESULTS: No significant differences were found in the bond strengths of the three groups evaluated (P> 0.05). The two groups in which APC Plus system was used left significantly less adhesive on the tooth than Transbond XT. TSEP/APC Plus left significantly less adhesive than Acid/APC Plus (P< 0.017).

Effect of surface treatments on the bond strength of brackets bonded with a compomer.

PURPOSE: To evaluate the effectiveness of the compomer Dyract AP for bonding brackets when conditioning the enamel with phosphoric acid and a non-rinsing conditioner (NRC), in comparison with a control group in which the resin orthodontic adhesive system Transbond XT was used. METHODS: The brackets were bonded to extracted premolars which were divided into three groups: (1) Acid/Transbond XT, (2) NRC/Dyract AP and (3) Acid/Dyract AP. Shear bond strength was measured with a universal testing machine. The crosshead speed was 1mm/minute. The adhesive remnant on the tooth after debonding was determined using image analysis equipment. RESULTS: The bond strength of Acid/Transbond XT was significantly higher than bond strengths of Acid/Dyract AP and NRC/Dyract AP (P< 0.017). No significant differences were observed between Acid/Dyract AP and NRC/Dyract APBond strength values (P> 0.017). Acid/Transbond XT left significantly more adhesive on the tooth than Acid/Dyract AP and NRC/Dyract AP, whereas NRC/Dyract AP left significantly less adhesive than Acid/Dyract AP (P< 0.05).

Effects of 3 adhesion promoters on the shear bond strength of orthodontic brackets: an in-vitro study.

INTRODUCTION: The objectives of this study were to (1) determine the effect of 3 adhesion promoters on shear bond strength and the amount of remnant adhesive on the teeth after debonding and (2) learn whether 1 promoter is material-specific, as stated by the manufacturer. METHODS: The promoters tested were OrthoSolo (Ormco, Orange, Calif), All-Bond 2 (Bisco, Schaumburg, Ill), and Enhance L.C. (Reliance, Itasca, Ill). Two adhesives were used: Transbond XT (3M Unitek, Monrovia, Calif) and Light Bond (Reliance). One hundred fifty premolars were divided into 6 groups of 25, and brackets were bonded according to the manufacturers' instructions: (1) Transbond XT, (2) Transbond XT plus All-Bond 2, (3) Transbond XT plus OrthoSolo, (4) Transbond XT plus Enhance L.C., (5) Light Bond, and (6) Light Bond plus Enhance L.C. Bond strength was tested on a universal testing machine, and remnant adhesive was quantified with image analysis equipment. RESULTS: The highest bond strength values were obtained when brackets were bonded with Light Bond plus Enhance L.C. These values were significantly higher than those achieved with Transbond XT, Transbond XT plus Enhance L.C., or Transbond XT plus All-Bond 2. Of the groups bonded with Transbond XT, the group that included OrthoSolo had the best results. CONCLUSIONS: None of the adhesion promoters significantly increased bond strength or the amount of adhesive remaining on the tooth after debonding. Enhance L.C. produced the greatest bond strength when used with the material-specific product Light Bond.

Adhesion promoters: effects on the bond strength of brackets.

PURPOSE: To evaluate the effect of two adhesion promoters on shear bond strength and remnant adhesive of brackets cemented with a light-cured orthodontic adhesive resin system. METHODS: The two adhesion promoters tested were OrthoSolo and All-Bond 2 Primer. Seventy-five upper premolars were divided into three groups of 25. A control group was established using Transbond-XT adhesive system and two experimental groups: Transbond-XT/OrthoSolo and Transbond-XT/All-Bond 2. Shear bond strength was measured using a universal testing machine and adhesive remnant was quantified using an image analysis equipment. RESULTS: The application of Orthosolo significantly increased bond strength for Transbond-XT adhesive system (P< 0.017). All-Bond 2 primer did not significantly increase the bond strength of Transbond-XT (P> 0.017). The Adhesive Remnant Index results and the analysis of the percentage of area of tooth occupied by adhesive indicated that adhesive remnant after debonding did not increase significantly (P> 0.05) with the use of either of the promoters.

Shear bond strength of orthodontic brackets bonded with self-etching primers.

PURPOSE: To evaluate the effectiveness of two self-etching primers for bonding brackets in comparison with the conventional acid-etch technique. METHODS: The brackets were bonded to extracted human premolars using the resin orthodontic adhesive system, Transbond XT. This procedure was carried out in accordance with one of the following three protocols of enamel conditioning: (1) 37% phosphoric acid etching, (2) Transbond Plus Self Etching Primer (TSEP), and (3) Adper Prompt L-Pop (Adper PLP). Shear bond strength was measured with a universal test machine. The adhesive remnant on the tooth after debonding was quantified using image analysis equipment. Scanning electron microscopy (SEM) was used to observe the effects of conditioning of each product on the enamel. RESULTS: No significant differences were observed in bond strengths of the three groups evaluated (P> 0.05). Self-etching primers left significantly less adhesive on the tooth than the conventional acid-etch technique and, among them, Adper PLP left significantly less adhesive than TSEP (P< 0.017). SEM observations showed that the etching effect of self-etching primers approximated to the etching effect of phosphoric acid.

A comparison of the shear bond strength of a resin cement and two orthodontic resin adhesive systems.

The object of this study was to compare the shear bond strength and the quantity of adhesive remaining on the tooth after the debonding of brackets bonded with two light-cured orthodontic resin adhesive systems (Transbond XT and Light-Bond) and a dual-cured resin cement (RelyX Unicem). Seventy-five premolars were divided into three groups. In each group, brackets were bonded with one of the adhesives according to the manufacturer's instructions. Shear bond strength was measured using a universal test machine at a crosshead speed of one mm/min, and adhesive remnant was quantified using image analysis equipment. Our results showed that the resin cement produced significantly lower bond strength than the two orthodontic resin adhesive systems. It was also observed that the bond strength produced by Light-Bond was significantly greater than that of Transbond XT. RelyX left significantly less remnant adhesive than Transbond XT and Light-Bond. Between the two orthodontic systems, Light-Bond left significantly less adhesive on the tooth than Transbond XT.

Prevention of habitual cheek biting: a case report.

Oral and peri-oral structures can be traumatized by self-injurious behavior (SIB). Various articles have described prostheses used to prevent SIB-related injuries to the oral tissues of patients who have developmental or medical problems, such as psychological problems, congenital syndromes or mental retardation; however, reports of oral SIB in individuals unaffected by the above conditions are scarce. This case report describes the use of a removable prosthesis to prevent a stress-induced cheek biting habit in 15-year-old girl who did not have any of the commonly related conditions. The report discusses the importance of designing a prosthesis that protects tissues, while considering injury severity and the patient's healthas well as her ability to cooperate with treatment.

Influence of food-simulating liquids on bond strength of brackets bonded with a HEMA-free and HEMA-containing self-etching primer.

OBJECTIVE: To evaluate the effect of food-simulating liquids on bond strengths of brackets bonded with a HEMA-free and a HEMA-containing self-etching primer. MATERIALS AND METHODS: Brackets were bonded to 280 bovine incisors that were divided into two groups: (1) Adper Prompt-L-Pop (Adper PLP)/Transbond-XT and (2) Transbond Plus self-etching primer (TSEP, HEMA-free)/Transbond-XT. Each group was evaluated under different storage conditions: 24 hours in water, thermocycling (T), T/12 weeks in water, T/12 weeks in 10% ethanol, T/12 weeks in 50% ethanol, T/12 weeks in 3% acetic acid, and T/12 weeks in olive oil. Shear bond strength was measured with a universal test machine. RESULTS: TSEP and Adper PLP showed a significantly higher bond strength at 24 hours than at T/12 weeks in 50% ethanol (P  =  .000). For Adper PLP, the bond strength at 24 hours was significantly higher than T/12 weeks in water (P  =  .000). Significant differences were not detected between the two bonding procedures for the different storage conditions (P > .05). CONCLUSION: Owing to its hydrophilic nature, the bond strength produced by Adper PLP (a HEMA-containing self-etching primer) decreased significantly after T/12 weeks in water. Brackets bonded with both TSEP and Adper PLP showed significantly higher bond strengths at 24 hours than at T/12 weeks in 50% ethanol, probably due to the effect of ethanol at 50% on Transbond-XT.

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

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.