Orthodontic brackets removal under shear and tensile bond strength resistance tests - a comparative test between light sources

We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 +/- 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased.

Effects of cervical headgear and edgewise appliances on growing patients

Maxillary basal bone, dentoalveolar, and dental changes in Class II Division 1 patients treated to normal occlusion by using cervical headgear and edgewise appliances were retrospectively evaluated. A sample of 45 treated patients was compared with a group of 30 untreated patients. Subjects were drawn from the Department of Orthodontics, Araraquara School of Dentistry, Brazil, and ranged in age from 7.5 to 13.5 years. The groups were matched based on age, gender, and malocclusion. Roughly 87% of the treated group had a mesocephalic or brachicephalic pattern, and 13% had a dolicocephalic pattern. Cervical headgear was used until a Class I dental relationship was achieved. Our results demonstrated that the malocclusions were probably corrected by maintaining the maxillary first molars in position during maxillary growth. Maxillary basal bone changes (excluding dentoalveolar changes) did not differ significantly between the treated and the untreated groups. Molar extrusion after the use of cervical headgear was not supported by our data, and this must be considered in the treatment plan of patients who present similar facial types. (Am J Orthod Dentofacial Orthop 2001;119:531-9).

Effect of 0.4% stannous fluoride gel on Streptococci mutans in relation to elastomeric rings and steel ligatures in orthodontic patients

Background: Patients with fixed orthodontic appliances often experience an absolute increase in the number of Streptococci mutans colony-forming units (cfu). The aim of this investigation was to study the development of biofilm and S. mutans cfu in connection with stainless steel ligatures and elastomeric rings in orthodontic patients treated with and without 0.4% stannous fluoride gel (SFG). Material: Forty-seven patients were divided into 2 groups: those treated with 0.4% SFG for 4 minutes (experimental) and those without 0.4% SFG (control). In each patient, elastomeric rings were used for ligation on 1 side of the dental arch midline, and stainless steel ligatures were used on the opposite side. Saliva samples were collected before and after appliance placement. At 15 and 30 days after appliance placement, biofilm samples from the stainless steel ligatures and the elastomeric rings were collected and subjected to microbiologic procedures and scanning electron microscopy (SEM) analysis. Results: The numbers of S. mutans cfu in the saliva and biofilm were not statistically different between the teeth fitted with elastomeric rings and stainless steel ligatures, or between the experimental and control groups. SEM analysis showed biofilm formation on both ligature ties. Conclusions: Topical application of 0.4% SFG in orthodontic patients with elastomeric rings or stainless steel ligatures does not cause a significant decrease in S. mutans cfu in the saliva and biofilm. Copyright © 2005 by the American Association of Orthodontists.

Gingival margin alterations and the pre-orthodontic treatment amount of keratinized gingiva

The purpose of this retrospective study was to associate the amount of keratinized gingiva present in adolescents prior to orthodontic treatment to the development of gingival recessions after the end of treatment. The sample consisted of the intra-oral photographs and orthodontic study models from 209 Caucasian patients with a mean age of 11.20 ± 1.83 years on their initial records and 14.7 ± 1.8 years on their final records. Patients were either Angle Class I or II and were submitted to non-extraction orthodontic treatment. Gingival recession was evaluated by visual inspection of the lower incisors and canines as seen in the initial and final study models and intra-oral photographs. The amount of recession was quantified using a digital caliper and the observed post-treatment gingival margin alterations were classified as unaltered, coronal migration of the gingival margin or apical migration of the gingival margin. The width of the keratinized gingiva was measured from the mucogingival line to the gingival margin on the pre-treatment photographs. The teeth that developed gingival recession and those that did not have their gingival margin position changed did not differ in relation to the initial amount of keratinized gingiva (3.00 ± 0.61 and 3.5 ± 0.86 mm, respectively). Paradoxically, teeth that presented a coronal migration of the gingival margin had a smaller initial amount of keratinized gingiva (2.26 ± 0.31 mm). The mean amount of initial keratinized gingiva did not predispose lower incisors and canines to gingival recession.

Efficacy of ultrasonic, electric and manual toothbrushes in patients with fixed orthodontic appliances

Objective: This crossover study compared the efficacy of an ultrasonic toothbrush for the reduction of plaque, gingival inflammation, and levels of Streptococcus mutans, in relation to an electric and a manual toothbrush. Materials and Methods: Twenty-one patients with orthodontic appliances were divided into three groups. All patients were evaluated by a periodontist and samples of saliva were collected for quantification of S mutans. The patients received their first brushes with appropriate instructions. For each crossover leg, patients used each toothbrush for a period of 30 days. At the end of each washout period, participants received a periodontal evaluation and new samples of saliva were collected. After 15 days of using their own toothbrushes, patients received the next toothbrushes in the experimental sequence. Results: The ultrasonic brush group presented significant improvement in the reduction of visible plaque on the buccal surfaces (-6.36%, P = .007). The counts of S mutans decreased in the electric (2.04 × 105 to 1.36 × 105 colony-forming units [CFU]/mL) and ultrasonic (2.98 × 105 to 1.84 × 105 CFU/mL) groups. There were no statistical differences among the three brushes for the clinical and microbiological parameters evaluated. Conclusions: This study did not demonstrate that the ultrasonic toothbrush was better in reducing gingival inflammation in adolescent orthodontic patients, but plaque scores were lowered on buccal surfaces of teeth with orthodontic brackets. In addition, S mutans counts were markedly decreased in the electric and ultrasonic groups, which should be related to a reduced risk of oral disease. © 2006 by The EH Angle Education and Research Foundation, Inc.

Anticariogenic effect of fluoride-releasing elastomers in orthodontic patients

This in vivo experimental study evaluated the efficacy of fluoride-releasing elastomers in the control of Streptococcus mutans levels in the oral cavity. Forty orthodontic patients were recruited and divided into two groups of 20. Fluoride-releasing elastomeric ligature ties (Fluor-I-Ties, Ortho Arch Co. Inc., USA) were used in the experimental group, and conventional elastomeric ligature ties (D. Morelli, Brazil), in the control group. Two initial samples of saliva were collected at a 14-day interval to determine the number of colony forming units (CFU) of Streptococcus mutans. Immediately after collecting the second sample, fluoride-releasing elastomeric ligature ties were placed in the patients of the experimental group, and conventional ligature ties, in the patients of the control group. Seven, 14 and 28 days after placement of the elastomeric ligature ties, saliva and plaque surrounding the orthodontic appliance were collected for microbiologic analysis. There were no significant differences in the number of Streptococcus mutans CFUs in saliva or plaque in the area surrounding the fluoride-releasing or conventional elastomeric ligature ties. Thus, fluoride-releasing elastomeric ligature ties should not be indicated to reduce the incidence of enamel decalcification in orthodontic patients. Since there was no significant reduction in S. mutans in saliva or plaque, other means of prevention against enamel decalcification should be indicated for these patients.

Occurrence, extension, and severity of gingival margin alterations after orthodontic treatment.

To assess the occurrence, extension, and severity of gingival margin alterations in a sample of youth after orthodontic treatment. Records from 209 Caucasian adolescents (118 female and 91 male) before and after orthodontic treatment were selected. Patients presented a mean age at the beginning of orthodontic treatment of 11.20 ± 1.86 years and a final mean age of 14.72 ± 1.83 years. Class I and II patients with mandibular incisors and canines that were completely erupted and with spacing or crowding not exceeding 4 mm were evaluated. The presence of gingival recession on the labial surface of the mandibular anterior teeth was evaluated in intraoral photographs and casts made before and after treatment. The proportion of patients with gingival recession after treatment was statistically higher than at the beginning (P<.001). After orthodontic treatment, gingival recession was not present in any of the teeth for 63.6% of the patients; in 29.2% of the patients, recession was present in at least 1 tooth. In terms of severity, the majority of affected teeth (47%) presented gingival recession less than 2 mm and in 2% more than 4 mm. It may be concluded that alterations in the gingival margin, especially gingival recession, occur in patients after orthodontic therapy, but the extent and severity of this finding are low. COPYRIGHT © 2007 BY QUINTESSENCE PUBLISHING CO, INC.

Uprighting impacted mandibular second molars with orthodontic elastic separating rings.

A 16-year-old girl presented with complaints of recurrent spontaneous pain in the mandibular second molar region. Treatment favored use of a simple uprighting technique involving orthodontic elastic separating rings.

Comparison of the shear bond strengths of conventional mesh bases and sandblasted orthodontic bracket bases

This study aimed to compare in vitro the shear bond strength between metallic brackets (Abzil) with conventional mesh bases and metallic brackets with bases industrially sandblasted with aluminum oxide using three adhesive systems, in order to assess the influence of sandblasting on adhesiveness and to compare 3 different bonding systems. Two hundred and forty bovine incisors were used and randomly divided into 6 groups (40 teeth in each group), according to the bracket base and to the bonding system. The brackets were direct-bonded in bovine teeth with 3 adhesive systems: System A - conventional Transbond™ XT (3M -Unitek); System B - Transbond™ Plus Self Etching Primer + Transbond™ XT (3M - Unitek) and System C - Fuji ORTHO LC resin-reinforced glass ionomer cement in capsules (GC Corp.). Shear bond strength tests were performed 24 hours after bonding, in a DL-3000 universal testing machine (EMIC), using a load cell of 200 kgf and a speed of 1 mm/min. The results were submitted to statistical analysis and showed no significant difference between conventional and sandblasted bracket bases. However, comparison between the bonding systems presented significantly different results. System A (14.92 MPa) and system C (13.24 MPa) presented statistically greater shear bond strength when compared to system B (10.66 MPa). There was no statistically significant difference between system A and system C.

Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times

The aim of this in vitro study was to compare the photoactivation effects of QTH (Quartz-Tungsten-Halogen) and LED (Light-Emitting Diode) on the SBS (Shear Bond Strength) of orthodontic brackets at different debond times. Seventy-two bovine lower incisors were randomly divided into two groups according to the photoactivation system used (QTH or LED). The enamel surfaces were conditioned with Transbond self-etching primer, and APC (Adhesive Pre-Coated) brackets were used in all specimens. Group I was cured with QTH for 20 s and Group II with LED for 10 s. Both groups were subdivided according to the different experimental times after bonding (immediately, 24 h and 7 days). The specimens were tested for SBS and the enamel surfaces were analyzed according to the Adhesive Remnant Index (ARI). The statistical analysis included the Tukey's test to evaluate the main effects of photoactivation and debond time on SBS. The Chi-square test was used to compare the ARI values found for each group, and no statistically significant difference was observed. The debond time of 7 days for QTH photoactivation showed statistically greater values of SBS when compared to the immediate and 24 h periods. There was no statistically significant difference between the QTH and LED groups immediately and after the 24 h period. In conclusion, bonding orthodontic brackets with LED photoactivation for 10 s is suggested because it requires a reduced clinical chair time.

Knowledge on dental trauma and orthodontic tooth movement held by a group of orthodontists

The objective of this work was to assess the knowledge about orthodontic tooth movement and dental trauma held by a group of orthodontists in specific areas of Brazil. For this purpose, 166 questionnaires with 15 objective questions about this subject were distributed. One hundred and five questionnaires were properly filled and collected after 30 days. It was concluded that, except for avulsion, the knowledge on dental injuries held by the professionals interviewed was considered unsatisfactory, and about 40% of them were not acquainted with the recommendations for the orthodontic movement of traumatized teeth.

Composite pontics for orthodontic patients with extraction spaces.

Esthetic orthodontic appliances continue to appeal to more patients, which results in objections to extraction spaces that remain for several months during orthodontic therapy. This has led orthodontists to design temporary pontics that fill extraction sites and that can be reduced as the spaces close. This report describes a simple, efficient, and expeditious technique for making such pontics. © 2010 Quintessence Publishing Co, Inc.

Effect of toothbrushing with different manual toothbrushes on the shear bond strength of orthodontic brackets

The aim of this study was to evaluate the effect of brushing with a Colgate 360° or Oral B Indicator 35 toothbrush on the shear bond strength of orthodontic brackets bonded to extracted human teeth. The bristle wear and bristle tip morphology were also examined after simulated tooth-brushing. Orthodontic brackets (Roth-P/1 st and 2 nd pre-molar S/D- Slot 0.18) were bonded (Transbond XT ®) to the smoothest surface of each of 45 extracted human molar and premolar teeth. Test specimens were randomly divided into three groups: Group 1, control group with no brushing; Group 2, brushing with the Oral B Indicator 35; Group 3, brushing with the Colgate 360°. Samples were adapted to a machine that simulated tooth-brushing. The bond strength of each bracket to each tooth was assessed with a mechanical testing machine. The bristle wear and bristle tip morphology indices were also assessed. Statistically significant differences were defined for p ≤ 0.05. The average bond strengths (range: 90.18-90.89 kgf/cm 2) did not differ among the three groups. The Colgate 360° showed less bristle wear and a better bristle tip morphology than the Oral B Indicator 35 toothbrush. However, use of either toothbrush did not decrease the bond strength of the orthodontic brackets. Therefore, patients undergoing orthodontic therapy can safely use either toothbrush.

In vitro study of shear bond strength in direct bonding of orthodontic molar tubes

Objective: Although direct bonding takes up less clinical time and ensures increased preservation of gingival health, the banding of molar teeth is still widespread nowadays. It would therefore be convenient to devise methods capable of increasing the efficiency of this procedure, notably for teeth subjected to substantial masticatory impact, such as molars. This study was conducted with the purpose of evaluating whether direct bonding would benefit from the application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface. Methods: A sample of 40 mandibular third molars was selected and randomly divided into two groups: Group 1 - Conventional direct bonding, followed by the application of a layer of resin to the occlusal surfaces of the tube/tooth interface, and Group 2 - Conventional direct bonding. Shear bond strength was tested 24 hours after bonding with the aid of a universal testing machine operating at a speed of 0.5mm/min. The results were analyzed using the independent t-test. Results: The shear bond strength tests yielded the following mean values: 17.08 MPa for Group 1 and 12.60 MPa for Group 2. Group 1 showed higher statistically significant shear bond strength than Group 2. Conclusions: The application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface was found to enhance bond strength quality of orthodontic buccal tubes bonded directly to molar teeth.

Influence of apical enlargement in cleaning and extrusion in canals with mild and moderate curvatures

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10° (GI) and 16 between 11° and 25° angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p<0.05) that those of the other groups, which were similar between themselves (p>0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.