Inflammatory parameters and color alterations of dental bleaching in patients wearing fixed orthodontic appliance: a randomized clinical trial.

BACKGROUND: Many orthodontic patients request dental bleaching during orthodontic treatment to achieve a faster aesthetic resolution, however, no attention has been paid to the inflammatory processes that can occur when both therapies are indicated together. So, this clinical trial evaluated the inflammatory parameters and color alterations associated with dental bleaching in patients wearing a fixed orthodontic appliance. METHODS: Thirty individuals aged between 18 and 40 years were equally and randomly allocated into three groups: FOA (fixed orthodontic appliance), BLE (dental bleaching), and FOA + BLE (fixed orthodontic appliance + dental bleaching). The orthodontic appliances and the bleaching procedures were performed in the maxillary premolars and molars. For dental bleaching a 35% hydrogen peroxide was used. The gingival crevicular fluid (GCF) and nitric oxide (NO-) levels were evaluated at different time-points. Color evaluation was performed using an Easyshade spectrophotometer at baseline (FOA, FOA + BLE, BLE), one month after (FOA + BLE) and 21 days after appliance removing (FOA + BLE and FOA groups), in each tooth bleached. The ANOVA and Tukey's tests, with a significance level of 5%, were used for statistical analysis. RESULTS: The GCF volume in the FOA + BLE and FOA groups significantly increased at the time points evaluated (p < 0.001); however, this did not occur in the BLE group (p > 0.05). On the other hand, NO- levels significantly decreased during dental bleaching with or without fixed orthodontic appliances (FOA + BLE and BLE groups; p < 0.05), while no significant changes were observed in the FOA group (p > 0.05). Significant changes in color were observed in the FOA + BLE and BLE groups compared to in the FOA group (p < 0.01). However, the presence of fixed orthodontic appliance (FOA + BLE) negatively affected the bleaching efficacy compared to BLE group (p < 0.01). CONCLUSIONS: Dental bleaching did not increase the inflammatory parameters in patients wearing fixed orthodontic appliance. However, in the presence of orthodontic appliances, the bleaching efficacy was lower than that of bleaching teeth without orthodontic appliances. TRIAL REGISTRATION: RBR-3sqsh8 (first trial registration: 09/07/2018).

Orthodontic Movement of Central Incisor with Previously-healed Root Fracture associated with Unerupted Canines.

Teeth with root fracture may need orthodontic treatment. This case report presents the management of unerupted canines in a patient with previously-healed/untreated horizontal root fracture in the maxillary left central incisor. The malocclusion was treated maintaining pulp vitality considering the principles to improve the eruption path of maxillary canines and move short-rooted teeth. The root-fractured tooth remained symptomless after orthodontic treatment without significant adverse effects, and stayed stable following 2-year follow-up.

Effectiveness of two thermal activated orthodontic archwire sequences based on transition temperature range during alignment: A randomized non-controlled comparative study.

INTRODUCTION: It has been suggested that heat-activated NiTi archwires (HANT) speed up crowding alleviation. HANT wires are available with different austenite finish temperatures. OBJECTIVE: The aim of the present study was to compare the effectiveness of two alignment sequences using thermally activated archwires with different austenite activation temperatures for the correction of mandibular anterior crowding. MATERIAL AND METHODS: The following NiTi archwire sequence was used for both groups: 0.012 in (conventional NiTi), 0.018 in (heat-activated NiTi archwires), 0.016×0.022 in (heat-activated NiTi archwires) and 0.019×0.025 in (conventional NiTi). The conventional NiTi used for both groups belongs to the same commercial brand. Two different austenite activation temperatures (35°C and 37°C) were used for the heat-activated archwires. The primary outcome was the degree of crowding correction measured on study models. The secondary outcome was crowding survival time over a six-month period. This RTC included fifty-four patients that were randomly allocated to the two different archwire sequences. A Mann-Whitney test was used to compare the groups regarding crowding alleviation. A survival curve was created using the Kaplan-Meier method to illustrate the reduction of crowding over time. A Mantel-Cox log-rank test was used to compare survival times (until correction of crowding). RESULTS: No differences in crowding alleviation were identified between both groups (log-rank test; P=0.77). CONCLUSIONS: The two alignment sequences with different thermal activated archwires at 35°C and 37°C achieved similar clinical results during the correction of mandibular anterior crowding.

Coated nickel titanium archwires and their uncoated counterparts: In-vitro contemporary comparison of unloading forces.

OBJECTIVE: To compare the unloading forces between aesthetic nickel titanium (NiTi) wires coated with rhodium and epoxy resin, as well as their uncoated equivalents. Additionally, intragroup comparisons between the different deactivation forces were evaluated, and the inner alloy cores were determined. MATERIAL AND METHODS: Forty-four 0.018" NiTi wire segments were equally divided into 4 groups: E- NiTi coated with epoxy resin, C- NiTi uncoated, R- heat-activated NiTi coated with rhodium, and T- heat-activated NiTi uncoated. The unloading values were recorded at 0.5, 1, 2, and 3mm using a 3-point bending test, according to the method in ISO Standard 15.841. Cross-sectional scanning electron microscopy was used to assess the inner alloy core thickness of the wires. RESULTS: The intergroup comparison was successively: at 0.5mm: E (1.21)>C (0.60)=R (0.63)=T (0.58); at 1mm: E (1.30)=C (1.23)>R (0.91)=T (0.80); at 2mm:C (1.93)>E (1.36)=R (1.20) and R (1.20)=T (1.00) and E (1.36)>T (1.00); at 3mm:C (2.44)>R (2.02)>E (1.62)=T (1.68). The intragroup comparisons showed for all groups that the forces were statistically higher at 3mm than the other deactivations (p<0.01). Group E presented a reduced inner alloy core (.0155). CONCLUSION: The unloading forces demonstrated variability between the wires tested and between the different deactivations. Therefore, depending on the type of movement required and the periodontal conditions, orthodontists should pay attention during archwire selection.

Comparative analysis of microorganism adhesion on coated, partially coated, and uncoated orthodontic archwires: A prospective clinical study.

INTRODUCTION: This study aimed to compare the microorganism adhesion on coated, partially coated, and uncoated orthodontic archwires after clinical use. The correlation between surface roughness (SR) and bacterial colonization was also evaluated. METHODS: A total of 48 archwire segments (0.016 × 0.022-in) were equally divided into 4 groups: nickel-titanium coated, nickel-titanium partially coated, uncoated stainless steel, and uncoated nickel-titanium. The archwires were randomly inserted in a split-mouth study design. After 4 weeks of clinical use, the total number of microorganisms adhering to the archwire was quantified and transformed into colony-forming units. SR was evaluated using a profilometer. A one-way and two-way ANOVA, post-hoc Tukey test, paired-samples t test, and Pearson correlation coefficient were used for statistical analysis. RESULTS: All the archwires presented microorganism adhesion, with the nickel-titanium-coated group demonstrating the highest value (P < 0.001). A statistically significant increase in SR was observed after clinical use for all groups (P < 0.05). No correlation between SR and bacterial adhesion was detected. CONCLUSIONS: Microorganism adhesion occurred on all of the archwires tested, especially on the esthetic fully coated. Because SR was not correlated with microorganism adhesion, future studies should evaluate the effect of surface free energy and superficial chemical changes on in-vivo microorganism adhesion.

Intrusion of maxillary molar using mini-implants: A clinical report and follow-up at 5 years.

This clinical report describes a straightforward alternative treatment for adult patients with extruded maxillary molars, who are reluctant to use fixed appliances and complex mechanics. The maxillary molar supereruption of a 57-year-old woman was treated using buttons bonded to the buccal and palatal surfaces of the molars, 2 mini-implants, and elastomeric chains. The intrusion was achieved in 5 months. The treatment stability was observed for 5 years after treatment.

Comparisons of surface roughnesses and sliding resistances of 6 titanium-based or TMA-type archwires.

Six titanium-based or TMA-type archwires (Beta III, Resolve, CNA, TMA, low-friction ion-implanted TMA or TMAL, and TiMolium) were studied as functions of composition, morphology, surface roughness, and sliding mechanics by using a scanning electron microscope, an x-ray energy dispersive wavelength analyser, a laser specular reflectometer, and a frictional testing machine. In the last instrument, all wires were coupled with 0.022-in stainless steel brackets in which normal forces were applied by 0.010-in stainless steel ligatures. With regard to composition, 5 wires were true beta-titanium alloys having nominal compositions of 80% titanium, 10% molybdenum, 6% zirconium, and 4% tin, and 1 was an alpha-beta alloy having a nominal composition of 90% titanium, 6% aluminum, 3% vanadium, and 1% other. Morphologies varied from surfaces with striations, scale, or layers of drawn material that suggested surface steps or fissures. Specular reflectance and optical roughness measurements divided the archwires into 2 groups of 3: Beta III, Resolve, and CNA had an overall mean value of 0.148 microm; and TMA, TMAL, and TiMolium had a mean overall value of 0.195 microm. These roughness measurements and their accompanying details of the compositional analyses suggested that there could be as few as 2 vendors manufacturing the 5 beta-titanium products. For 6 different values of angulation that embraced the passive and active regions of sliding, the coefficients of friction varied rather narrowly from 0.17 to 0.27 and were independent of surface roughnesses. Although these contemporary products are better than their predecessors of over a decade ago, other issues might be more important than surface finishes or frictional resistances because all products appear fairly comparable.