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INTRODUCTION: Although several studies have discussed nickel influence on the development of immunological reactions in orthodontic patients, it is noticed that the evidence towards the appliances, as well as towards the possible consequences of this material on the oral and general health of the individual are still inconsistent. OBJECTIVE: The aim of this article is to present the current stage of knowledge on this issue, highlighting the most recent findings considering the periodontal and humoral aspects of allergic subjects.

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There is no reason for Dentistry to use different terms for phenomena defined in Physics, the specific field in which concepts associated with forces are established and adapted. In place of pressure/tension, the compression/traction pair should be used. This study defines each one of these terms and justifies their use. Our contemporary world demands standardized criteria, methods, measures, concepts and terms to ensure that study protocols, results and applications are used in the same way in any country or area of human action.

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OBJECTIVE: To evaluate shear bond strength of 3 adhesive systems (Single Bond, TransbondTM MIP and TransbondTM XT) applied on bovine enamel under saliva contamination condition. METHOD: One hundred and twenty enamel surfaces of bovine incisors were divided into 6 groups (n = 20) according to the adhesive system used (TransbondTM XT, TransbondTM MIP and Single Bond) with or without saliva contamination. For each adhesive system, there were two groups defined as no contamination group (NC): 37% H3PO4 conditioning for 30 seconds and two layers of adhesive systems; saliva contamination group (SC): After the first adhesive layer application, the examined areas were contaminated with saliva. Samples were mounted appropriately for testing and stored in deionized water at 37 ºC for 7 days. Samples were then submitted to shear bond strength trials at a speed of 0.5 mm/min. The Adhesive Remnant Index (ARI) was evaluated under stereomicroscopy. Two-way analysis of variance and the Tukey test were used to compare mean values (α = 0.05). RESULTS: Groups XT (NC) = 26.29 ± 7.23; MIP (NC) = 24.47 ± 7.52 and SB (NC) = 32.36 ± 4.14 XT (SC) = 19.59 ± 6.76; MIP (SC) = 18.08 ± 6.39 and SB (SC) = 18.18 ± 7.03 MPa. ARI 0 and 1 were the most prevalent scores in all study groups examined. CONCLUSION: Saliva contamination significantly decreased bond strength of the three adhesive systems examined (p <0.05). However, the comparison of groups with and without saliva contamination did not reveal any significant differences, and, therefore, the three systems may be considered equivalent.

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INTRODUCTION: Laser applications have increased in a variety of dental procedures, especially in surgeries of soft tissues. Radiation is not invasive and is very well tolerated by tissues. CO2 laser acts in small vessels promoting blood coagulation, making it possible to work in a controlled way. Patients undergoing fixed orthodontic therapy often present injuries of gingival hyperplasia, originating esthetical and functional problems. OBJECTIVE: This study aimed at evaluating the CO2 laser effectiveness in removal of hyperplasia lesions in gingival papilla regions of patients with fixed orthodontic appliances. For this, ten patients were chosen and in these 75 teeth with gingival hyperplasia were identified. Measures from the papilla to incisal edge were performed with the use of a digital caliper. Besides that, the individuals were submitted to previous examinations to the surgical procedure with laser: Full blood count, blood coagulation profile and fasting blood glucose. After this, patients were submitted to the surgery for lesion removal, carried out at the Laser Center of FOUFBA, utilizing a CO2 laser machine (Sharplan 20C, Tel Aviv, Israel). RESULTS: It was showed that laser provided a significant increase (p<0,001) in the distance from the papilla to the incisal edge of the teeth, with no tissue contraction, aspects which were maintained for over two months. CONCLUSION: It can be concluded that CO2 laser has proved to be effective in removal of papillary gingival hyperplasia lesions.

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OBJECTIVE: To investigate the most commonly fabricated orthodontic retainers. METHODS: Information on the type and amount of maxillary and mandibular retainers produced in a three-month period was collected from six laboratories in the cities of São Paulo, Mauá and Guarulhos - Brazil. The retainers were grouped according to the total production. For the maxillary arch, the groups were: 1S - Begg retainer, 2S - Hawley retainer, 3S - transpalatal arch retainer, 4S - buccal resin-arch retainer and 5S - vacuum-formed retainer, Planas appliance, bonded lingual retainer and V-loop bonded lingual retainer. The groups relative to the mandibular arch were: 1I - 3-3 bonded lingual retainer (canine to canine), 2I - Hawley retainer and V-loop bonded lingual retainer, 3I - Begg retainer, 4I - buccal resin-arch retainer, vacuum-formed retainer and Planas appliance. The data were presented in box plots. Groups were compared using the Student's-t test with Bonferroni correction. RESULTS: The average of maxillary appliances fabricated ranged from 189.5 (1S) to 3.95 (5S). There were significant differences between groups 1S versus 5S and 2S versus 5S (p < 0.0001). Mean values for the mandibular retainers ranged from 55.3 (1I) to 4.2 (4I). Significant difference was observed between groups 2I and 4I (p < 0.0001). CONCLUSIONS: For the maxillary arch, the most requested retainers were Begg and Hawley retainers. Regarding the mandibular arch, bonded lingual retainers and Hawley retainer were the most frequent ones.

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INTRODUCTION: External apical root resorption (EARR) is an adverse outcome of the orthodontic treatment. So far, no single or associated factor has been identified as responsible for EARR due to tooth movement. OBJECTIVE: This study investigated the association of risk variables (age, gender, extraction for orthodontic treatment and Angle classification) with EARR and orthodontic treatment. METHOD: The sample (n=72) was divided into two groups according to presence (n=32) or absence (n=40) of EARR in maxillary central and lateral incisors after orthodontic treatment. RESULTS: There were no statistically significant differences in EARR according to age, gender, extraction or type of malocclusion (p>0.05). CONCLUSION: The risk variables examined were not associated with EARR in the study population.

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OBJECTIVE: The establishment of normal occlusal relationships in patients with cleft lip and palate using rapid maxillary expansion may promote good conditions for future rehabilitation. OBJECTIVE: This study describes the clinical case of monozygotic twins with unilateral cleft lip and palate at the age of mixed dentition, who were treated using the same rapid maxillary expansion protocol, but with two different screws (conventional and fan-type expansion screw). Results were evaluated using plaster models, intraoral and extraoral photographs, and Cone-Beam computed tomography (CBCT) scans obtained before the beginning of the treatment, (T1). METHODS: The patients were followed up for 6 months after maxillary expansion, when the same tests requested at T1 were obtained again for review (T2). T1 and T2 results were compared using lateral cephalometric tracings and measurements of the intercanine and intermolar distances in the plaster models using a digital caliper. RESULTS: The two types of expansion screws corrected the transverse discrepancy in patients with cleft lip and palate. The shape of the upper arches improved at 10 days after activation. CONCLUSION: CBCT scans provide detailed information about craniofacial, maxillary and mandibular changes resulting from rapid maxillary expansion. The most adequate screw for each type of malocclusion should be chosen after detailed examination of the dental arches.

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OBJECTIVE: The present study assessed some cephalometric measurements of the soft tissue profile in order to observe the behavior of facial convexity in patients with Class I, Class II division 1, and Class II division 2 malocclusions. METHODS: One hundred and thirty pre-treatment teleradiographs of Caucasian patients aged 10-16 years (mean age of 12.6 years) were selected for study and divided into 3 groups. The cephalometric measurements used in the present study were the following: H.SN, Cx, NLA, MLA, UL-SUL-S, LL-S, IMPA, and 1-SN. Analysis of variance and Tukey's test were applied for measurements H.SN, Cx, IMPA, 1-SN, MLA, and NLA, whereas Kruskal-Wallis and Dunn's tests were applied for UL-S and LL-S. RESULTS: The results showed statistically significant differences for the measurements H.SN, Cx, UL-S, and IMPA between Groups I, II-1 and II-2 (p < 0.05). Measurements LL-S and MLA showed statistically significant difference between Groups I and II-1 only (p < 0.05). On the other hand, no statistically significant differences were found for measurement NLA among the 3 groups (p < 0.05). CONCLUSION: Regarding facial characteristics expressed by measurements H.SN, Cx, and UL-S, one could conclude that Class II division 1 and Class II division 2 malocclusions, both differed from Class I malocclusion. In addition, Class II division 1 malocclusion was found to have facial characteristics expressed by MLA, which differentiate it from the Class II division 2 and Class 1 malocclusions. Class I, Class II division 1 and Class II division 2 malocclusions showed no difference in facial characteristics expressed by the measurement NLA, and measurement LL-S was directly related to eversion of the lower lip.

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OBJECTIVE: Early identification of craniofacial morphological characteristics allows orthopedic segmented interventions to attenuate dentoskeletal discrepancies, which may be partially disguised by natural dental compensation. To investigate the morphological characteristics of Brazilian children with Class III malocclusion, in stages I and II of cervical vertebrae maturation and compare them with the characteristics of Class I control patients. METHODS: Pre-orthodontic treatment records of 20 patients with Class III malocclusion and 20 control Class I patients, matched by the same skeletal maturity index and sex, were selected. The craniofacial structures and their relationships were divided into different categories for analysis. Angular and linear measures were adopted from the analyses previously described by Downs, Jarabak, Jacobson and McNamara. The differences found between the groups of Class III patients and Class I control group, both subdivided according to the stage of cervical vertebrae maturation (I or II), were assessed by analysis of variance (ANOVA), complemented by Bonferroni's multiple mean comparisons test. RESULTS: The analysis of variance showed statistically significant differences in the different studied groups, between the mean values found for some angular (SNA, SNB, ANB) and linear variables (Co - Gn, N - Perp Pog, Go - Me, Wits, S - Go, Ar - Go). CONCLUSION: Assessed children displaying Class III malocclusion show normal anterior base of skull and maxilla, and anterior positioning of the mandible partially related to increased posterior facial height with consequent mandibular counterclockwise rotation.

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INTRODUCTION: There are medications capable of affecting bone metabolism and the rate of tooth movement. Among these medications are the immunosuppressants, which act by repressing the action of T lymphocytes, however they can cause bone loss and consequently lead to osteoporosis. Osteoporosis is a common complication following kidney, heart, liver or lung transplantation. The immunosuppressant treatment for preventing organ rejection after transplantation, in general, includes glucocorticoids, cyclosporine, tacrolimus, and sirolimus. All these drugs can have jeopardizing effects on bone mineral homeostasis and consequently influence tooth movement. In recent years, however, the increasing use of immunosuppressants has raised questions about their effects on bone metabolism in patients undergoing orthodontic treatment. OBJECTIVE: The objective of this review study was to inform orthodontists about the influence of immunosuppressants on bone metabolism and tooth movement.

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OBJECTIVE: General dentist orthodontic practice is a controversial issue and this paper aims to analyze it comparing foreign laws to Brazilian Legal System. METHODS: Regulations and scientific texts concerning orthodontic practice by general dentists, in Portuguese or English language, were sought. RESULTS AND CONCLUSION: Portugal clearly forbids general dentist orthodontic practice; United States of America do not clearly forbid general dentist orthodontic practice, but do regulate and promote campaigns to encourage public to seek specialist service; in Australia and England, corrective orthodontics are offered both by orthodontists and general dentists; it was not possible to evaluate how orthodontic services are provided in Eastern Europe; and the fact that general dentists are forbidden to practice corrective orthodontics in Brazilian Legal System is compatible to other countries policy.

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OBJECTIVE: To compare in vitro shear bond strength (SBS) of different orthodontic adhesives in bonding and repeatedly rebonding metal brackets, and to evaluate the bond failure site with the adhesive remnant index (ARI). METHODS: Specimens consisted of 90 extracted human first premolars, randomly divided into three groups (n=30). The adhesives Alpha Plast (AP), ConciseTM (CO) and TransbondTM XT (TB) were used in each group. Three SBS tests were performed, i.e., one at T0 (initial) and the other two at T1 and T2 (first and second rebondings, respectively), observing a 24-hour interval. The tests were performed in a Shimadzu AG-I (10kN) SBS testing machine, at a speed of 0.5 mm/min. RESULTS: SBS data were subjected to ANOVA, Tukey's test and Bonferroni test (p<0.05). For the ARI, the Kruskal Wallis test was performed, followed by the Dunn test. The results revealed that at T0 groups AP and CO showed SBS values that were near, but above TB values; and at T1 and T2, the highest SBS values were observed for the AP group, followed by the CO and TB groups. CONCLUSION: Statistically significant differences were found in SBS between groups AP, CO and TB during bonding and repeated rebondings of unused metal brackets, with group AP achieving the highest SBS value. Regarding ARI, adhesive AP exhibited bond failure at the enamel-adhesive interface, with a higher enamel fracture frequency.

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INTRODUCTION: Apical root resorption is a frequent and occasionally critical problem in orthodontic patients undergoing induced tooth movement. One of the factors that might influence prognosis, especially in maxillary incisors, which most frequently present resorptions, are the so-called the anatomical barriers; that is, proximity of the buccal and palatal cortical bones to the maxillary incisor roots. OBJECTIVE: The purpose of this research was to investigate whether patients with excessive vertical growth really present a small distance between the alveolar cortical bones and the maxillary incisor roots, and whether there is a correlation between this distance and the root resorption index in comparison with patients presenting horizontal growth. METHODS: The sample comprised orthodontic records of 18 patients with extraction planning of first maxillary premolars and treatment by the standard and/or preadjusted edgewise brackets. Their initial and final periapical radiographs were evaluated to determine the amount of root resorption that occurred. RESULTS: On the palatal side, patients with excessive vertical growth (Group 2 - SN-GoGn > 43º) showed a narrower alveolar bone than the horizontal growth patients (Group 1 - SN-GoGn < 29º). However, the distance between the buccal cortical bone and the central incisor root apex showed no significant difference between Groups 1 and 2; CONCLUSIONS: It was concluded that there are no correlations between the proximity of buccal cortical bone, maxillary incisor roots and the root resorption index.

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OBJECTIVE: To assess the frequency and severity of the signs and symptoms of temporomandibular disorders (TMD), the frequency of parafunctional oral habits and the correlation between the variables by means of the patients' perception regarding their problem. METHODS: One hundred patients diagnosed with TMD, through a clinical examination of their masticatory system, answered the questions of a previously published protocol concerning the signs and symptoms most frequently reported in the literature. RESULTS: According to the results from the non parametric statistical analysis, the frequency for the following signs and symptoms was significant: Fatigue and muscle pain, joint sounds, tinnitus, ear fullness, headache, chewing impairment and difficulty to yawn (p<0.01) and otalgia (p<0.05). As to the parafunctional oral habits, there was a significant presence of teeth clenching during the day and night (p<0.01) and teeth grinding at night (p<0.05). The variable correlation analysis showed that there was a positive correlation between symptom frequency and severity; age was correlated with the presence of otalgia, cervical pain and teeth sensitivity, besides being correlated with muscle and joint pain severity. Habit frequency was negatively correlated with age. TMD duration was also positively correlated with the symptoms of tinnitus, ear fullness, muscle and joint pain. CONCLUSION: The study results showed that the anamnestic assessment using ProDTMMulti can predict the severity of the TMD case.

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INTRODUCTION: Among the sleep disorders reported by the American Academy of Sleep, the most common is obstructive sleep apnea-hypopnea syndrome (OSAHS), which is caused by difficulties in air passage and complete interruption of air flow in the airway. This syndrome is associated with increased morbidity and mortality in apneic individuals. OBJECTIVE: It was the objective of this paper to evaluate a removable mandibular advancement device as it provides a noninvasive, straightforward treatment readily accepted by patients. METHODS: In this study, 15 patients without temporomandibular disorders (TMD) and with excessive daytime sleepiness or snoring were evaluated. Data were collected by means of: Polysomnography before and after placement of an intraoral appliance, analysis of TMD signs and symptoms using a patient history questionnaire, muscle and TMJ palpation. RESULTS: After treatment, the statistical analysis (t-test, and the "before and after" test) showed a mean reduction of 77.6% (p=0.001) in the apnea-hypopnea index, an increase in lowest oxyhemoglobin saturation (p=0.05), decrease in desaturation (p=0.05), decrease in micro-awakenings or EEG arousals (p=0.05) and highly significant improvement in daytime sleepiness (p=0.005), measured by the Epworth Sleepiness Scale. No TMD appeared during the monitoring period. CONCLUSION: The oral device developed in this study was considered effective for mild to moderate OSAHS.

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INTRODUCTION: The possibility that orthodontic treatment in childhood might be a risk factor for the development of temporomandibular disorders (TMD) later in life has been an issue of great controversy in dental literature. OBJECTIVE: To determine a possible negative or positive correlation between orthodontic treatment and TMD by presenting the results and conclusions from a number of key-papers dealing with this subject. RESULTS AND CONCLUSION: According to current knowledge, there is no scientific evidence to support that orthodontic treatment is a risk factor for the development of TMD. On the other hand, there is some evidence to support that a proper orthodontic treatment performed in childhood might have a positive effect upon the functional status of the masticatory system later in life.

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OBJECTIVE: This study compared the dental arch morphology of adult patients with isolated cleft palate in order to verify the influence of palatoplasty on occlusion. METHODS: Cast models of 77 patients, 30 males and 47 females, with an average age of 21 years and no syndromes were taken. They were in the permanent dentition and had not undergone orthodontic treatment. The sample was divided into non-operated and operated patients, the latter having been submitted to palatoplasty at a mean age of 2.2 years. RESULTS: Almost 80% of the sample exhibited sagittal discrepancies in the inter-arch relationship, with a Class II malocclusion prevailing (59.74%) followed by Class III (20,78%), regardless of palatoplasty. Transverse analysis showed a 23% incidence of posterior crossbite also not influenced by palatoplasty. Intra-arch relationship indicated that constriction and crowding on the upper arch were more frequent in the operated group (p=0.0238 and p=0.0002, respectively), showing an influence of palatoplasty on its morphology. The predominant morphological characteristics in patients with isolated cleft palate were a Class II malocclusion, upper dental arch constriction and upper and lower anterior crowding. CONCLUSION: The influence of palatoplasty was restricted to constriction and crowding of the upper dental arch, with no interference from the extension of the cleft, except for the upper crowding, which occurred more in patients with complete cleft palates.

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OBJECTIVE: The purpose of this study was to compare the effectiveness of trigger points injections using lidocaine 0.5% and dry needling without any kind of home-based rehabilitation program. METHODS: Sixteen patients with myofascial pain and trigger points in masticatory muscles were randomly assigned to two groups and received only one application session. The pressure pain threshold (PPT) was recorded before and after the injection: Ten minutes, 24 hours later, 7, 15, 21 and 30 days after the treatment. Visual analogue scale (VAS) was used to in all evaluation periods. RESULTS: There were no difference between groups for PPT, but for all groups the PPT during the time significantly increased when compared the before treatment. VAS showed differences between groups and during the time. The 0.5% lidocaine had the lowest VAS values when compared to dry needling, but at 30 days there were no differences among them. CONCLUSIONS: Despite the differences in VAS and considering there were no differences in PPT increases, we concluded that, in this study, both groups were able to disrupt the mechanisms of trigger point and relieve the myofascial pain symptoms.

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OBJECTIVE: The aim of this work was to establish the prevalence of non-nutritive sucking habits (pacifier and/or digit sucking) and to assess its relation with anterior open bite. METHODS: The sample consisted of 980 records of children of both genders, with ages between 3 and 12 years, who were treated at the Pediatrics Clinic of the University of Pernambuco (FOP/UPE), from February 2000 trough December 2005, both sexes. Pearson's Chi-square test at 5% level of significance was used for statistical assessment. RESULTS: It was observed that 17,7% of the sample had some habit at the moment of the anamnesis (9,6% of digit sucking habit, 8,8% of pacifier sucking habit and 0,7% of both habits) and that the prevalence of open bite was 20,3%. The prevalence of sucking habits in girls was much higher than in boys (22,6% and 12,9%, respectively) and this difference was statistically significant (p = 0,000). A correlation between habits and open bite was proved statistically (p = 0,000): Children with sucking habits had 8 times more chances of developing anterior open bite. CONCLUSIONS: Anterior open bite was associated to the presence of non nutritive sucking habits; sucking habits were more prevalent in girls and in children between three and six years of age.

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OBJECTIVE: The aim of this study was to evaluate if there is correlation between perception of facial esthetic and divine proportion, verifying if most attractive faces are closer to and less attractive faces are more distant to this proportion. METHODS: Standard facial photographs (frontal and lateral) in natural head position were taken of a sample of 85 Brazilian Caucasian women, with mean age of 23 years and 9 months. The photographs were evaluated by 5 orthodontists, 5 artists and 5 laymen and were classified, according to their subjective analysis of facial esthetic, in pleasant, acceptable and not pleasant. Frontal photographs were evaluated by divine proportion analysis using the computerized method. RESULTS AND CONCLUSIONS: According to subjective analysis the sample consisted 18.8% of pleasant, 70.6% of acceptable and 10.6% of not pleasant faces. After statistical analysis, a lack of agreement was verified in esthetic facial preferences among the three groups of observers. It was also possible to verify that in this research there was no correlation between perception of facial beauty and divine proportion.

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INTRODUCTION: Even though the upper canine is the tooth that presents most eruption anomalies, after the third molars, canine retention prevalence in the population is quite low. Local, physiologic and pathologic factors can provide difficulties for the tooth eruptive process. The correct diagnosis in trying to prevent upper canine retention with ectopic eruption is fundamental to choose the ideal treatment, which can be performed by various methods. OBJECTIVE: The present paper has the purpose of approaching aspects related to impacted upper permanent canines by a literature review, including localization and treatment conducts.

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OBJECTIVE: The present prospective clinical study was designed in order to evaluate horizontal and vertical skeletal alterations induced by the use of Herbst appliance in individuals with Class II, division 1 malocclusion during mixed dentition stage. METHODS: The sampling consisted of 15 pre-pubertal individuals (12 boys and 3 girls; initial age 9 years and 6 months), who were treated with Herbst appliance for a period of 7 months. The effects of the treatment were compared to a group of 15 individuals with Class II, division 1 malocclusion (8 boys and 7 girls, initial age averaged 9 years and 1 month), orthodontically untreated, who were followed up for a period of 12 months. Statistical analysis was performed with Student's t-test with significance level at 5%. RESULTS: It was showed that the treatment with Herbst appliance in mixed dentition stage has restricted maxilla growth. Mandibular and palatal planes have not undergone significant alteration; however, anterior and posterior facial heights have increased significantly. Facial convexity and maxillomandibular relationship were altered positively. Mandible has positioned significantly forward and its effective length increased 2.5 times more than the increase observed in control group. CONCLUSION: It was possible to conclude that Herbst appliance was able to provide satisfactory results in individuals during mixed dentition stage.

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INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc) and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

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OBJECTIVE: To evaluate qualitative and quantitative changes in the saliva of individuals undergoing orthodontic treatment with fixed appliances. METHODS: Salivary samples were collected from 50 individuals divided in two groups: Experimental Group - patients with fixed orthodontic appliances (n=25); and Control Group - subjects with no orthodontic appliances (n=25). Salivary flow rate, pH, buffering capacity, amylase activity, concentrations of total proteins, calcium and glucose were measured in all salivary samples. RESULTS: There was a reduction in salivary pH and buffering capacity and an increase in the concentration of calcium ions in the experimental group (p<0.05); there was also an increase in glucose, amylase and protein concentrations in the saliva of the Experimental Group, but the differences were insignificant. There was insignificant correlation between calcium ion concentration and salivary flow or between buffering capacity and salivary flow. CONCLUSION: The saliva of individuals with fixed orthodontic appliances had lower pH, buffering capacity and calcium concentration than that of individuals without any type of orthodontic appliance. These oral changes are enough to cause tooth demineralization. Patients with orthodontic appliances should adopt additional oral hygiene procedures.

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Open bite is defined as a deficiency in normal vertical contact between antagonist teeth and may manifest in a limited region, or more rarely throughout the entire dental arch. If the lack of contact between teeth is located in the incisor and/or canine region when occlusion is in centric relation, it is called anterior open bite (AOB). Some studies have demonstrated that AOB is strongly associated with non-nutritional sucking habit. This article relates the treatment of a female African-Brazilian patient, with 20 years and 7 months of age, who presented Angle's Class II, division 1 malocclusion, AOB, accentuated overjet, lingual interposition during swallowing and difficulty with pronouncing some phonemes. Orthodontic treatment began by mounting an Edgewise Standard fixed appliance system, with a fixed palatal crib appliance and extraction of maxillary first premolars. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO), as part of the requisites to become a BBO Diplomate.

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INTRODUCTION: Sliding mechanics is widely used during orthodontic treatment. One of the disadvantages of this mechanics is the friction generated at the bracket/archwire interface, which may reduce the amount of desired orthodontic movement obtained. Due to the application and great acceptance of this type of mechanics, the role of friction in Orthodontics has been of interest for both clinicians and scientists. OBJECTIVE: Therefore, this article discussed how friction affects orthodontic tooth movement, with an approach to its clinical implications as well as the evolution of dental materials and its properties regarding resistance to sliding.