Bracket Slot Size Research Articles

A Prospective Randomized Clinical Trial to Evaluate the Slot Size on Pain and Oral Health-Related Quality of Life (OHRQoL) in Orthodontics during the First Month of Treatment with Conventional and Low-Friction Brackets

The aim of this research project was to analyze the influence of slot size and low-friction on pain and the oral health-related quality of life (OHRQoL) of subjects receiving fixed appliances. A group of 120 patients (61 male, 59 female) were chosen for this randomized clinical trial. Participants were classified into four groups (30 patients in each). We compared conventional (C group) and low-friction (LF group) brackets and 0.018″ and 0.022″ slots. Pain was assessed at 4 (T0), 8 (T1), and 24 (T2) hours, and 2 (T3), 3 (T4), 4 (T5), 5 (T6), 6 (T7), and 7 (T8) days after the start of treatment by using the visual analogue scale (VAS). OHRQoL was assessed at 1 month using the Oral Health Impact Profile (OHIP-14). Data was analyzed using the analysis of variance (ANOVA) test with post-hoc Bonferroni correction. For pain on the visual analogue scale, statistically significant differences (p < 0.05) were found for T0 and T3. For OHRQoL, statistically significant differences (p < 0.01) were found in the domains of physical pain, psychological discomfort, psychological disability, and overall OHIP. The group with 0.022″ low-friction brackets showed a lower pain score and less impact on OHRQoL. The type of bracket system used and bracket slot size influenced patients’ perceptions of pain and their OHRQoL.

OPTIMUM FORCE SYSTEM FOR EN-MASSE RETRACTION OF SIX MAXILLARY ANTERIOR TEETH IN LABIAL ORTHODONTICS

The orthodontists generally do not recommend application of force system above the archwire level owing to additional attachments and patient’s discomfort. Hence, the present research study focusses on application of retraction force system at the archwire level. The objective of this study is to specify an optimum combination of archwire and bracket slot size for en-masse (simultaneous) parallel retraction of six maxillary anterior teeth in labial orthodontics (LaO). In this research study, the concept (theoretical) model has been developed based on simple principles of mechanics to estimate the torque generated by different sizes of archwire in bracket slots. Based on torque value, retraction force developed by each combination of archwire and slot size was determined and compared with required retraction force of 150 gram-force on each side of sagittal plane. For combination of [Formula: see text] inch stalinless steel SS archwire and 0.022 inch SS bracket slot, magnitude of computed retraction force matched closely with aforementioned required force than other combinations and hence, it is recommended in the present research study. The validation of selected combination of archwire and bracket slot size was done successfully by in vivo (clinical) experimentation on three patients. Thus, it proves that the aforementioned combination of archwire and bracket slot size is more suitable than others for retraction force system applied at archwire level.

Does anchorage loss differ with 0.018-inch and 0.022-inch slot bracket systems?

To compare maxillary first molar anchorage loss between 0.018-inch and 0.022-inch slot fixed appliance systems. Patients requiring bilateral maxillary premolar extractions (n = 74) within a randomized clinical trial comparing the effectiveness of 0.018-inch and 0.022-inch slot MBT bracket systems (3M-Unitek, Monrovia, Calif) were included. Three-dimensional pre- and posttreatment digital models were landmarked and measured (R700 scanner and OrthoAnalyzer software, 3Shape, Copenhagen, Denmark). Anteroposterior position of the first molars was measured using the third medial rugae point as a reference. Anchorage loss (AL) represented the subtraction of the posttreatment distance from the pretreatment distance for both anchorage loss right (ALR) and left (ALL) sides. The values were then compared using a two-way analysis of variance. There were 41 and 33 cases for the 0.018-inch and 0.022-inch bracket slot systems, respectively. The baseline characteristics were similar between groups, except for the presence or absence of anchorage devices (P = .050). For the total sample: 0.018-inch ALR = 3.86 mm, ALL = 3.30 mm and 0.022-inch ALR = 3.73 mm, ALL = 3.47 mm (P = .970). There was also no significant difference between the 0.018-inch and 0.022-inch groups when subjects with anchorage devices were excluded (P = .383). Bracket slot size does not influence maxillary molar anchorage loss during orthodontic treatment.

Bracket slot size selection: after all a matter of taste?

The publication of the three-paper series on the effects of two slot sizes on treatment parameters in this issue, targets a topic, which has attracted a lot of discussion based primarily on anecdotal evidence. The conclusive evidence contribute to the lack of variation of treatment variables with slot size selection, clarifies one of the traditional beliefs on this issue; several others still hold strong however. This commentary has the objective of highlighting some points, which could be taken into consideration in interpreting the results of this three-part trial.

Radiographic Comparison of Apical Root Resorption During Orthodontic Treatment with Bracket Slot Size 0,018 inch and 0,022 inch

Objectives: Orthodontic induced apical root resorption is an unavoidable side effect of orthodontic treatments which is seen in more than 90% of the cases. Orthodontic Induced Inflammatory Root Resorption (OIIRR) occurs as a result of individual biologic variations and mechanical stimuli effects. Material and method: In this study the extent of root resorption is compared in patients who have received fixed orthodontic treatment (by straight wire system), with two different sizes of slots (0.018 inch and 0.022 inch) and the same wire diameter. For this purpose, panoramic radiographs were used to examine some 720 teeth before and after the treatment. Two different approaches were used to evaluate the root resorption, first based on Malgren classification and the other based on Crown-Root ratio (C/R). Result: Average duration of treatment for patients treated by 0.018-inch slot brackets was 26 months and for those who were treated by 0.022-inch slot brackets it was 25 months. No significant difference was found in the two groups explored in this study (p-value = 0.684). Slot size has no effect on root resorption and there are some other features including the efficiency of the slots which might be influential. Conclusion: As no significant difference was found in the two groups explored in this study, it could be argued that slot size has no effect on root resorption and there are some other features including the efficiency level of the slots which might be influential. As previous studies indicate, 0.022-inch slot brackets could have more influence on root resorption. Apex shape has no effect in that regard.

The effect of bracket slot size on the effectiveness of orthodontic treatment: A systematic review.

To assess, by means of a systematic review, the scientific evidence of the influence of 0.018-inch or 0.022-inch bracket slots on treatment time, efficiency of space closure, efficiency of alignment, quality of orthodontic finishing, level of discomfort, and level of root resorption. The PubMed, Bireme, Medline, Scopus, Web of Science, Open Grey, and Google Scholar databases were searched, with no date and language restrictions, for randomized clinical trials and controlled clinical trials, using controlled terms related to bracket slots. After the selection and removal of duplicate articles, the risk of bias was assessed, and the data from the included studies were extracted by two independent researchers. The search yielded 2640 studies. After applying the eligibility criteria, eight articles were fully read and four studies were selected for the qualitative systematic review. No randomized clinical trials assessed the duration of treatment in patients treated with 0.018-inch and 0.022-inch bracket slots. Due to heterogeneity of the data available, a meta-analysis could not be conducted. While most studies indicated a shorter duration of treatment in patients with 0.018-inch bracket slots, no available data confirmed the higher efficiency of one system over the other. The biases in the studies did not allow for a reliable conclusion; therefore, new studies with a better methodologic design are needed.

Effects of bracket slot size during en-masse retraction of the six maxillary anterior teeth using an induction-heating typodont simulation system.

ObjectiveTo investigate how bracket slot size affects the direction of maxillary anterior tooth movement when en-masse retraction is performed in sliding mechanics using an induction-heating typodont simulation system.MethodsAn induction-heating typodont simulation system was designed based on the Calorific Machine system. The typodont included metal anterior and resin posterior teeth embedded in a sticky wax arch. Three bracket slot groups (0.018, 0.020, and 0.022 inch [in]) were tested. A retraction force of 250 g was applied in the posterior-superior direction.ResultsIn the anteroposterior direction, the cusp tip of the canine in the 0.020-in slot group moved more distally than in the 0.018-in slot group. In the vertical direction, all six anterior teeth were intruded in the 0.018-in slot group and extruded in the 0.020- and 0.022-in slot groups. The lateral incisor was significantly extruded in the 0.020- and 0.022-in slot groups. Significant differences in the crown linguoversion were found between the 0.018- and 0.020-in slot groups and 0.018- and 0.022-in slot groups for the central incisor and between the 0.018- and 0.022-in slot groups and 0.020- and 0.022-in slot groups for the canine. In the 0.018-in slot group, all anterior teeth showed crown mesial angulation. Significant differences were found between the 0.018- and 0.022-in slot groups for the lateral incisor and between the 0.018- and 0.020-in slot groups and 0.018- and 0.022-in slot groups for the canine.ConclusionsUse of 0.018-in slot brackets was effective for preventing extrusion and crown linguoversion of anterior teeth in sliding mechanics.

Comparison of the frictional characteristics of aesthetic orthodontic brackets measured using a modified in vitro technique.

ObjectiveThe coefficients of friction (COFs) of aesthetic ceramic and stainless steel brackets used in conjunction with stainless steel archwires were investigated using a modified linear tribometer and special computer software, and the effects of the bracket slot size (0.018 inches [in] or 0.022 in) and materials (ceramic or metal) on the COF were determined.MethodsFour types of ceramic (one with a stainless steel slot) and one conventional stainless steel bracket were tested with two types of archwire sizes: a 0.017 × 0.025-in wire in the 0.018-in slots and a 0.019 × 0.025-in wire in the 0.022-in slot brackets. For pairwise comparisons between the 0.018-in and 0.022-in slot sizes in the same bracket, an independent sample t-test was used. One-way and two-way analysis of variance (ANOVA) and Tukey's post-hoc test at the 95% confidence level (α = 0.05) were also used for statistical analyses.ResultsThere were significant differences between the 0.022-in and 0.018-in slot sizes for the same brand of bracket. ANOVA also showed that both slot size and bracket slot material had significant effects on COF values (p < 0.001). The ceramic bracket with a 0.022-in stainless steel slot showed the lowest mean COF (µ = 0.18), followed by the conventional stainless steel bracket with a 0.022-in slot (µ = 0.21). The monocrystalline alumina ceramic bracket with a 0.018-in slot had the highest COF (µ = 0.85).ConclusionsBrackets with stainless steel slots exhibit lower COFs than ceramic slot brackets. All brackets show lower COFs as the slot size increases.

Longer treatment times with self-ligated orthodontic brackets.

The Medline, Cochrane Library, Biomed Central, BBO including LILACS, Ind Med, Sceilo, Clinical trials.gov, Conference paper Index, Digital Dissertations, German National Library of Medicine (ZB MED), Google Scholar, ISI Web of Knowledge, metaRegister of Controlled Trials, OpenSIGLE and Scirus databases were searched. Randomised controlled trials (RCTs) and quasi-RCTs in patients having fixed-appliance orthodontic treatments were considered. Study assessment data extraction and risk of bias assessment was carried out independently by two reviewers. Overall quality of evidence was based on the Grades of Recommendation Assessment, Development and Evaluation (GRADE) approach. Random-effects meta-analyses were performed where data could be pooled. Twenty five trials (1321 patients) were included. The majority (24) compared self-ligated (SL) and conventional brackets (CL). No trials primarily investigated the effect of bracket material and no indirect comparison was possible. Two trials assessed the bracket slot size but found no consistent difference between 0.022'' and 0.018'' brackets. Four studies contributed to a meta-analysis that showed overall duration of the orthodontic treatment be significantly longer in the SL group by 2.01 months (95%CI; 0.45 to 3.57). Based on existing evidence, no clinical recommendation can be made regarding the bracket material or different ligation modules. For Sl brackets, no conclusive benefits could be proven, while their use was associated with longer treatment durations.

Coefficients of friction for arch wires in stainless steel and polycrystalline alumina bracket slots. I. The dry state

The surface roughness and the coefficients of friction were measured for sixteen arch wire-bracket combinations. The sample included one rectangular arch wire product from each of the four principal alloy groups and one bracket product from among the stainless steel and polycrystalline alumina inventory. Although subsamples representing both the 0.018-inch and the 0.022-inch slot sizes were evaluated, no differences were observed in their rankings. When tested over a series of eight incident angles, the optical surface roughness of representative stainless steel and alumina brackets averaged 0.148 and 0.193 microns, respectively. After testing at a single angle (82 degree) and referencing a nomogram, the roughness of the stainless steel, cobalt-chromium, beta-titanium, and nickel-titanium arch wire surfaces averaged 0.053, 0.129, 0.137, and 0.247 microns, respectively. When the various arch wire-bracket couples were pressed against an 0.010-inch stainless steel ligature wire at 34 degrees C and otherwise prevailing atmospheric conditions, the coefficients of friction ranged from stainless steel (lowest) to cobalt-chromium, nickel-titanium, and beta-titanium (highest)--regardless of bracket product or slot size. These results corroborated earlier observations in which the same arch wire products were drawn between stainless steel or alumina contact flats. In the current research, the average coefficient of kinetic friction for the stainless steel couple (0.139) was less than that for the stainless steel arch wire against a polycrystalline alumina bracket (0.174).