Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients.

INTRODUCTION: This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested. METHODS: Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n = 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n = 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides. RESULTS: Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P = 0.412 and P = 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P = 0.011, P = 0.024, and P = 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P = 0.008), mandibular ramus height (P = 0.004), condyle height (P = 0.010) and gonion to midsagittal plane distance (P = 0.018). CONCLUSIONS: Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Is there variation in the depth of the curve of Spee in individuals with different dentoskeletal patterns? A systematic review with meta-analysis.

OBJECTIVE: To systematically evaluate all the evidence assessing variations in the depth of the curve of Spee (COS) according to the presence/absence of different dentoskeletal characteristics. SEARCH METHODS AND ELIGIBILITY CRITERIA: The eligibility criteria were outlined following the PECO framework, as follows: studies evaluating individuals with complete permanent dentition including second molars (P), which compared a group with a certain dentoskeletal variation (E) versus another group without the variation (C), regarding the depth of the COS (O). MEDLINE (via PubMed), Scopus, Web of Science, The Cochrane Library, LILACS and BBO (via Virtual Health Library), OpenGrey, and Google Scholar were searched up to September 2021 to identify eligible reports. DATA COLLECTION AND ANALYSIS: Duplicates were removed from all the records retrieved. The selection process and data collection were performed independently by two review members. The risk of bias was also assessed independently and in duplicate, using the guideline described by Fowkes and Fulton. Several meta-analyses (α = 0.05) were conducted to estimate the mean differences (MD) or standardized mean differences (SMD) in the depth of COS between individuals presenting or not certain dentoskeletal characteristics. The certainty of evidence was assessed using the GRADE tool. RESULTS: Thirty-five studies were selected for qualitative synthesis, and 29 of them for quantitative synthesis. All studies had methodological limitations that affected the risk of bias and increased the likelihood that results were due to chance. Syntheses showed that Class II malocclusion (SMD = 0.87; 95% CI: 0.61, 1.13; P < 0.00001; six datasets including 260 subjects analysed), Class II division 1 (SMD = 1.09; 95% CI: 0.62, 1.56; P < 0.00001; 14 datasets including 823 subjects analysed) and Class II division 2 (SMD = 2.65; 95% CI: 1.51, 3.79; P < 0.00001; eight datasets including 476 subjects analysed) had deeper COS than Class I malocclusion. The skeletal Class II also presented higher COS values than skeletal Class I (SMD = 0.57; 95% CI: 0.02, 1.12; P = 0.04; four datasets including 299 subjects analysed). Individuals with Class III malocclusion had flatter COS than the subjects having Class I malocclusion (SMD = -0.57; 95% CI: -1.07, -0.08; P = 0.02; nine datasets including 505 individuals analysed). No difference was shown in the COS depth between skeletal Class III and Class I (P > 0.05). Deep bite individuals had higher COS depth than those with normal overbite (MD = 0.61; 95% CI: 0.41, 0.82; P < 0.00001; two datasets including 250 subjects analysed). In addition, hypodivergent individuals presented deeper COS than normodivergents (SMD = 0.62; 95% CI: 0.37, 0.86; P < 0.00001; six datasets including 305 subjects analysed), and there was no significant difference in the COS depth between hyperdivergent and normodivergent individuals (P = 0.66). The certainty of evidence was rated as very low for all the syntheses. LIMITATIONS: All the quantitative syntheses included results from studies with methodological flaws. Therefore, they are potentially biased. Moreover, the evidence was also mainly affected in terms of the inconsistency of the results and the imprecision of the estimates. CONCLUSIONS: Although an apparent influence of dentoskeletal Class II, Class III malocclusion, deep bite, and the hypodivergent skeletal pattern on the depth of the COS is suggested, it is not possible to make definitive conclusions on the matter due to the very low certainty of the evidence. Further high-quality research is necessary.

Skeletal and alveolar changes in conventional rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE): a prospective randomized clinical trial using low-dose CBCT.

BACKGROUND: This prospective randomized clinical trial aimed to evaluate the immediate and short-term skeletal, dentoalveolar, and periodontal effects of rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE) in adolescent and young adult patients. METHODS: This study followed a two-arm, parallel, randomized clinical trial design that recruited patients with transverse maxillary deficiency in a 1:1 allocation ratio. Forty patients (14 men and 26 women) requiring maxillary expansion were randomly allocated to the RPE (n = 20, age = 14.0 ± 4.5) or MARPE (n = 20, age = 14.1 ± 4.2) groups. The assignment was performed via computer-generated block randomization, with a block size of four. Upon identical (35 turns) amount of expansion, low-dose cone-beam computed tomography images were taken before treatment (T0), immediately after expansion (T1), and after a 3-month consolidation period (T2). The primary outcome of this study comprised the assessment of midpalatal suture separation. Secondary outcomes included, skeletal, dentoalveolar, and periodontal measurements, which were performed at each time point. RESULTS: The frequency of midpalatal suture separation was 90% (18/20) and 95% (19/20) for the RPE and MARPE groups, respectively. A greater increase in nasal width in the molar region (M-NW) and greater palatine foramen (GPF) was observed immediately after the expansion (T1-T0) and consolidation periods (T2-T0) in the MARPE group compared to the RPE group (P < 0.05). The MARPE and RPE groups showed similar dentoalveolar changes except for the maxillary width (PM-MW, M-MW). The MARPE group presented greater bilateral first premolar (PM-MW) and molar (M-MW) maxillary width in relation to the RPE group (P < 0.05). Through the expansion and consolidation periods (T2-T0), lesser buccal displacement of the anchor teeth was observed in the MARPE group (PM-BBPT, PM-PBPT, M-BBPT [mesial and distal roots], and M-PBPT)( P < 0.05). CONCLUSIONS: Midpalatal suture separation was observed in 90% and 95% of patients in the RPE and MARPE groups, respectively. Both RPE and MARPE groups exhibited significant triangular basal bone expansion and skeletal relapse during consolidation. Under identical amounts of expansion, the MARPE group showed lower decrease in the skeletal, dentoalveolar and periodontal variables after consolidation. The reinforcement of RPE with miniscrews contributes to the maintenance of the basal bone during consolidation period. Trial registration WHO Institutional Clinical Trials Registry Platform (IRB No. KCT0006871 / Registration date 27/12/2021).

Immediate changes in condylar position after rapid maxillary expansion.

INTRODUCTION: Although the dentoalveolar and skeletal effects of rapid maxillary expansion are well documented, the condylar response to this procedure is not well understood. The purpose of this study was to test the following null hypothesis: rapid maxillary expansion promotes immediate changes of the position of the condyles in patients with Class I malocclusion. METHODS: Thirty-four subjects with Class I malocclusion underwent rapid maxillary expansion. Cone-beam computed tomography images were collected before activation of the expander and 3 weeks later, after screw stabilization. Using specific software functions, it was possible to determine and reproduce head positioning and landmarks during the different times of the study. RESULTS: The axial, coronal, and sagittal planes were examined, and no asymmetries in condylar positions were found at either time. However, statistically significant anterior and inferior displacements of these structures occurred, with respective average values of 0.52 and 0.49 mm. Lateral inclinations of both condyles were observed and confirmed by the coronal condylar angles. CONCLUSIONS: The null hypothesis was rejected. Statistically significant anterior and inferior displacements of the condyles occurred. Lateral inclination of the condyles was observed.

Response of masticatory muscles to treatment with orthodontic aligners: a preliminary prospective longitudinal study.

INTRODUCTION: The emergence of orthodontic aligners has provided an aesthetic and comfortable option for orthodontic treatment. However, the encapsulated design of the aligners can influence the masticatory muscles, and might compromise safe treatment. OBJECTIVE: This preliminary longitudinal study aimed to investigate whether the use of orthodontic aligners affects the biting force and myoelectric activity of the superficial masseter and anterior temporal muscles. METHODS: Ten subjects participated in the study and underwent treatment during an 8-month follow-up period. The root mean square (RMS), the median power frequency (MPF) of the surface electromyography (sEMG) signals, and the biting force (kgf) were recorded and normalized relative to the pretreatment condition. The data were analyzed by repeated-measure analysis of variance (ANOVA), with the significance level set at 5%. RESULTS: Both the superficial masseter and the anterior temporal muscles presented an increase in sEMG signal activity during the treatment, with a marked increase in the latter compared to the former (p<0.05). Moreover, a significant decrease in bite force was evidenced (p<0.05). CONCLUSIONS: This preliminary study observed that the orthodontic aligners affected the muscle recruitment pattern of masticatory muscles, and reduced biting performance during the 8-month follow-up period.

Three-dimensional micromorphology of human midpalatal suture and pterygomaxillary articular complex.

BACKGROUND: Sutures exist in the craniofacial area, and the pattern of maturation and synostosis of facial sutures is largely unknown. METHODS: For a comprehensive understanding of the three-dimensional circummaxillary suture micromorphology, human midpalatal suture (MPS) and pterygomaxillary articular complex from eight subjects' (five males, three females, 72-88 years old) autopsies were longitudinally scanned with microcomputed tomography. Additional histology was performed for hematoxylin and eosin staining. Sutural micromorphology was assessed by interdigitation index (II), obliteration index (OI) and obliteration number. Intergroup comparisons were performed with Kruskal-Wallis and Mann-Whitney U with Bonferroni correction (α = 0.005). Correlation with anteroposterior and craniocaudal gradients was assessed with Spearman's correlation test (α = 0.05). RESULTS: Maxillary region of MPS presented a higher II 1.50 (0.61) and obliteration number per slice 8 (9) (P < 0.005). OI was increased in palatomaxillary 35% (47%) followed by pterygopalatine suture 25% (49%) (P < 0.005). The II and OI of the MPS exhibited only a weak anteroposterior gradient, with relatively low correlations. Obliteration areas were found sporadically along the entire MPS. CONCLUSIONS: Based on these findings, it is conceivable that the success of nonsurgical maxillary expansion largely depends on individual variations in sutural morphology and maturation rather than appliance design.

Histomorphometric study of the periodontal ligament in the initial period of orthodontic movement in Wistar rats with induced allergic asthma.

INTRODUCTION: Asthma is a common systemic disease occurring in infancy and adolescence, time periods that could encompass orthodontic treatment. Asthma is an inflammatory disease; therefore, it might interfere with orthodontic tooth movement. The purpose of the study was to analyze the histomorphologic aspects of the periodontal ligament of asthmatic Wistar rats in the initial period of orthodontic movement. METHODS: Thirty-two Wistar rats were divided into 4 groups: 2 control groups consisting of rats without induced allergic asthma, and 2 experimental groups consisting of rats with induced allergic asthma. The animals of the first control and experimental groups did not receive orthodontic forces, whereas those in the second control and experimental groups were subjected to mesial movement of the maxillary left first molar for 3 days. The samples were prepared for histomorphometric analysis of the periodontal ligament. The area of the periodontal ligament was calculated as a function of root length in the cervical and apical regions of the distal face of the maxillary first molar mesial root. The Student t test and the Welch correlation test were applied to the data obtained. RESULTS: There was a statistically significant difference (P <0.05) between the control and experimental groups. An enhanced response to orthodontic force was observed in the asthmatic animals: the periodontal ligament was more compressed at the pressure area and more stretched in the traction area. CONCLUSIONS: Our findings indicate that experimental allergic asthma seems to exacerbate orthodontic movement in rats.

Effects of induced precocious puberty on cranial growth in female Wistar rats.

This investigation examined the effects of pharmacologically induced precocious puberty on cranial growth in Wistar rats. Forty-eight female newborn Wistar rats were divided into two groups: a control group (C) and an experimental group (E), with four subgroups of six animals each. The time interval from birth until sacrifice differed between the subgroups, and was set at 30, 60, 90, and 120 days. An intramuscular single dose (300 µg) of steroid hormone danazol was administered on day 5 after birth, as a means of inducing precocious puberty. Alizarin (2 mg/100 g) was administered to three animals in each subgroup three days prior to sacrifice. Body mass and dates corresponding to the beginning of the oestrous cycle were recorded. Craniometric measurements were undertaken. Histological analysis using light and fluorescence microscopy was then carried out to qualitatively and quantitatively evaluate the spheno-occipital synchondrosis and to visualize bone deposition patterns. The results were analysed with a Student's t-test and analysis of variance. Precocious puberty was effectively induced and differences between groups denoted an earlier maturation in the experimental rats. In qualitative analysis, a significant increase of total synchondrosis width was noted only in group E60, in comparison with C60, and an increase in the E90 subgroup cortical bone width compared with the C90 subgroup. Histomorphometrically, a statistical difference between total width values of subgroups E60 (434.3 µm) and C60 (323.5 µm) was detected. However, body mass and macroscopic measurements did not show statistically significant differences. An appropriate model for studying bone growth associated with precocious puberty in Wistar female rats was not achieved using steroid hormone danazol, when evaluated at 30 day intervals.

The importance of the diagnostic setup in the orthodontic treatment plan.

The aim of this study was to address the importance of the diagnostic setup by examining two cases where diagnostic setups were made in order to determine the treatment plan. The diagnostic setup is a fundamental aid and should be used when there are doubts in the orthodontic planning.

Therapeutic effects of botulinum toxin type A in subjects with gummy smile: A longitudinal sEMG approach.

OBJECTIVE: To evaluate the response of the myoelectric activity of levator labii superioris (LLS), levator labii superioris alaeque nasi (LLSAN), and minor zygomatic (Zm) muscles in individuals with gummy smile, volunteers to botulinum toxin type A (BTX-A) application, with a follow-up of 6 months. MATERIALS AND METHODS: Thirteen individuals were submitted to clinical evaluation and photographic records to monitor the variations of the gingival display (GD) during posed smile. The recording of the surface electromyography (sEMG) signal of muscles studied was performed in three tasks: posed smile (PS), upper lip elevation (ULE) and nose wing elevation (NWE). The root-mean-square value, an amplitude sEMG signal parameter, was extracted from the sEMG signals. One and three-way ANOVA were applied, and the level of significance set at 5%. RESULTS: There were significant differences (P<0.05) in the sEMG signal activity from the control condition (before BTX-A application - T0) to the 8th week of follow up, which was accompanied by clinical evaluation for the gingival display (P<0.05). The peak of the reduction in sEMG signals occurred 2 weeks after T0 for all the studied tasks, with the exception of the left hemiface in the PS, which showed a peak of reduction 4 weeks after T0. CONCLUSIONS: BTX-A led to a decrease in the sEMG signal amplitude over 2 to 4 weeks after application in the muscles, although differently concerning each hemiface when recruited to perform other mouth tasks. During the PS, the recruitment level of the upper lip elevator muscles was compatible with the clinical response obtained in the follow-up period in this study, which corroborates the sEMG assessment to clinical data.

Dentofacial and skeletal pattern in African descendants from southeastern Brazil: clinical prospective study.

OBJECTIVE: The aim of this study was to evaluate characteristics of African-Brazilians young adults with excellent dental occlusion, including bimaxillary protrusion; compare them to European-American Caucasian standards, and determine whether there is sexual dimorphism in the display of this phenotype. METHODS: Lateral cephalometric radiographs were obtained from 43 African-Brazilians within military personnel (28 males and 15 females, average age 22.4 ± 3.4 years) with normal occlusion, selected from a group of 394 volunteers. Thirty-one angular and linear measurements were evaluated. Student's t-test for independent samples was used to compare results with those established by European-American standards, previously described in the literature. RESULTS: Considering the dentoalveolar pattern, seven angular and six linear measurements showed statistically significant differences (p< 0.001) when compared to Caucasian cephalometric standards. African-Brazilians' subjects showed lower cranial base angle (SNAr = 119.87 ± 5.66º) and anterior cranial base length (SN-distance = 68.63 ± 4.50 mm) (p< 0.001). The maxilla (SNA = 88.51 ± 3.23º) and the mandible (SNB = 85.06 ± 3.24º) were protruded in relation to the SN line (p< 0.001). Sexual dimorphism was significant for L1.NB (degrees) (p< 0.01), and interincisal angle (U1.L1) (p< 0.05). CONCLUSION: African-Brazilian young adults presented differences regarding dental and craniofacial characteristics, when compared to European-American norms. It can be stated that Caucasian cephalometric norms should not be applied to African-Brazilian faces.

Reasons influencing the preferences of prospective patients and orthodontists for different orthodontic appliances.

OBJECTIVE: To evaluate the reasons influencing the preferences for a certain type of orthodontic appliance over another among prospective patients (PP) and orthodontists. METHODS: A total of 49 PP and 51 orthodontists were asked about their preferences for the following appliances: clear aligners (CA), lingual metallic brackets (LMB), polycrystalline and monocrystalline ceramic brackets, and buccal metallic brackets (BMB). The participants rated the importance of 17 potential reasons that would explain their choices. The reasons that contributed most to these preferences were identified. Non-parametric tests (Fisher's exact, χ2 and Mann-Whitney tests) and multivariate analyses (regression and discriminant analysis) were used to assess the data (α = 0.05). RESULTS: CA and BMB were the most chosen appliances by PP and orthodontists, respectively. LMB was the most rejected option among both groups of participants (p < 0.001). Rates of the importance of pain/discomfort, smile esthetics, finishing details, and feeding/speech impairment showed the highest differences between PP and orthodontists (p < 0.0005). Discriminant analyses showed that individuals who considered treatment time and smile esthetics as more important were more likely to prefer CA, while those who prioritized finishing details and cost were more likely to choose BMB (p < 0.05). CONCLUSIONS: Reasons related to comfort and quality of life during use were considered as more important by PP, while those related to the results and clinical performance of the appliances were considered as more relevant by orthodontists.

Surface morphologic evaluation of orthodontic bonding systems under conditions of cariogenic challenge.

Orthodontic bonding systems are submitted to demineralization and remineralization dynamics that might compromise their surface smoothness, and favor biofilm aggregation and caries development. The aim of the present study was to evaluate the effects of a cariogenic challenge model (in vitro pH-cycling model) on the surface roughness and topography of 3 bonding materials: Transbond™ XT (XT), Transbond™ Plus Color Change (PLUS) and Fuji Ortho™ LC (FUJI), by means of Atomic Force Microscopy (AFM). Six specimens with standardized dimensions and surface smoothness were fabricated per group, and the materials were manipulated in accordance with the manufacturers' instructions. No polishing was necessary. AFM tests were performed before and after pH-cycling, taking 3 readouts per specimen. The roughness results (Ra) were obtained at nanometric levels (nm) and surface records were acquired in two- and three-dimensional images of height and lock-in phase of the material components. The surfaces of all groups analyzed in the study were morphologically altered, presenting images suggestive of matrix degradation and loss of matrix-load integrity. FUJI presented the greatest increase in surface roughness, followed by XT and PLUS, respectively (p≤0.001). Nevertheless, the roughness values found did not present sufficient degradation to harbor bacteria. The surface roughness of all tested materials was increased by pH-cycling. The use of materials capable of resisting degradation in the oral environment is recommended, in order to conserve their integrity and of the surrounding tissues.

Macroscopic and microscopic evaluation of flapless alveolar perforations on experimental tooth movement.

OBJECTIVE: The aim of this study was to evaluate a flapless surgical technique as an alternative to traditional alveolar corticotomy used to accelerate orthodontic tooth movement (OTM). METHODS: To induce OTM in Wistar rats, 40 cN of orthodontic force were applied to the maxillary left first molars. Forty rats were distributed into control groups (CG1, CG3, CG7 and CG14) and experimental groups (n= 5), in which alveolar perforations were made using a spear-shaped guide bur (EG1, EG3, EG7, EG14). Euthanasia dates were set at 1, 3, 7 and 14 days, respectively, after tooth movement began. The amount of OTM was measured with a caliper, and osteoclasts present in the periodontal ligament of the mesial root of the moved tooth were counted by means of histological evaluation (tartrate-resistant acid phosphatase staining, TRAP). RESULTS: Although there was no difference in the amount of OTM within subgroups of corresponding experimental periods (p> 0.05), when EG14 and CG14 were compared, a larger number of osteoclasts was counted in the experimental group (p< 0.00). CONCLUSION: The authors concluded that flapless cortical alveolar perforations led to more intense osteoclastic activity on the fourteenth day; nevertheless, no evidence of accelerated OTM could be noted.

Mini-implant selection protocol applied to MARPE.

INTRODUCTION: Rapid maxillary expansion (RME) is the therapy of choice to correct skeletal transverse dimension in children and adolescents, associating orthopedic and dental effects. In an attempt to prevent the undesirable dentoalveolar effects and optimize the potential of skeletal expansion in individuals in advanced stages of skeletal maturation, the miniscrew-assisted rapid palatal expander (MARPE) was proposed by Lee et al. in 2010. OBJECTIVE: This paper presents a systematized protocol for selection of miniscrews indicated for MARPE, by the evaluation of cone-beam computed tomographies (CBCT). Variables related with the bone and soft tissue thicknesses at the palatal regions of interest, as well as in relation to the fixation rings of miniscrews of the palatal expander are analyzed and discussed to provide better performance in the clinical practice.

Response of masticatory muscles to treatment with orthodontic aligners: a preliminary prospective longitudinal study

ABSTRACT Introduction: The emergence of orthodontic aligners has provided an aesthetic and comfortable option for orthodontic treatment. However, the encapsulated design of the aligners can influence the masticatory muscles, and might compromise safe treatment. Objective: This preliminary longitudinal study aimed to investigate whether the use of orthodontic aligners affects the biting force and myoelectric activity of the superficial masseter and anterior temporal muscles. Methods: Ten subjects participated in the study and underwent treatment during an 8-month follow-up period. The root mean square (RMS), the median power frequency (MPF) of the surface electromyography (sEMG) signals, and the biting force (kgf) were recorded and normalized relative to the pretreatment condition. The data were analyzed by repeated-measure analysis of variance (ANOVA), with the significance level set at 5%. Results: Both the superficial masseter and the anterior temporal muscles presented an increase in sEMG signal activity during the treatment, with a marked increase in the latter compared to the former (p<0.05). Moreover, a significant decrease in bite force was evidenced (p<0.05). Conclusions: This preliminary study observed that the orthodontic aligners affected the muscle recruitment pattern of masticatory muscles, and reduced biting performance during the 8-month follow-up period.

RESUMO Introdução: O surgimento dos alinhadores ortodônticos tem proporcionado uma opção estética e confortável para o tratamento ortodôntico. No entanto, o design encapsulado dos alinhadores pode influenciar os músculos mastigatórios e comprometer a segurança do tratamento. Objetivo: Este estudo longitudinal preliminar teve como objetivo investigar se o uso de alinhadores ortodônticos afeta a força de mordida e a atividade mioelétrica dos músculos masseter superficial e temporal anterior. Métodos: Dez indivíduos participaram do estudo e foram submetidos a tratamento durante um período de acompanhamento de 8 meses. A raiz quadrada média (RMS), a frequência mediana de potência (FMP) dos sinais de superfície da eletromiografia (sEMG) e a força de mordida (kgf) foram registradas e normalizadas em relação à condição de pré-tratamento. Os dados foram analisados por análise de variância para medidas repetidas (ANOVA), com nível de significância estabelecido em 5%. Resultados: Tanto o masseter superficial quanto o temporal anterior apresentaram aumento da atividade do sinal sEMG durante o tratamento, com aumento acentuado desse último em comparação ao primeiro (p<0,05). Além disso, foi evidenciada uma diminuição significativa da força de mordida (p<0,05). Conclusões: Esse estudo preliminar observou que os alinhadores ortodônticos afetaram o padrão de recrutamento muscular dos músculos mastigatórios e reduziram o desempenho da mordida durante o período de acompanhamento de oito meses.

Miniscrew-assisted rapid palatal expansion for managing arch perimeter in an adult patient.

INTRODUCTION:: Etiology of dental crowding may be related to arch constriction in diverse dimensions, and an appropriate manipulation of arch perimeter by intervening in basal bone discrepancies cases, may be a key for crowding relief, especially when incisors movement is limited due to underlying pathology, periodontal issues or restrictions related to soft tissue profile. OBJECTIVES:: This case report illustrates a 24-year old woman, with maxillary transverse deficiency, upper and lower arches crowding, Class II, division 1, subdivision right relationship, previous upper incisors traumatic episode and straight profile. A non-surgical and non-extraction treatment approach was feasible due to the miniscrew-assisted rapid palatal expansion technique (MARPE). METHODS:: The MARPE appliance consisted of a conventional Hyrax expander supported by four orthodontic miniscrews. A slow expansion protocol was adopted, with an overall of 40 days of activation and a 3-month retention period. Intrusive traction miniscrew-anchored mechanics were used for correcting the Class II subdivision relationship, managing lower arch perimeter and midline deviation before including the upper central incisors. RESULTS:: Post-treatment records show an intermolar width increase of 5 mm, bilateral Class I molar and canine relationships, upper and lower crowding resolution, coincident dental midlines and proper intercuspation. CONCLUSIONS:: The MARPE is an effective treatment approach for managing arch-perimeter deficiencies related to maxillary transverse discrepancies in adult patients.

Dental staining after orthodontic debonding: effectiveness of two bleaching treatment protocols - in vitro study

Objective: The aim of this study was to compare the effectiveness of two bleaching treatment protocols to treat dental staining after orthodontic debonding. Materials and Methods: Twenty four bovine teeth were submitted to orthodontic bracket (Morelli, Edgewise Prescription, Slot 22) bonding (Transbond XT, 3M) and debonding, which were divided into three groups according to the bleaching protocol: hydrogen peroxide 10% (Whiteness, FGM) simulating home bleaching protocol (Home Bleaching Group), hydrogen peroxide 35% Whiteness, FGM) simulating dental office bleaching protocol (Office Bleaching Group) and Control Group, which was not exposed to any dental bleaching protocol, and stored in distilled water at 37°C. The specimens were submitted to the following processes: aging of resin remaining tegs by ultraviolet (UV), staining with coffee solution and tooth bleaching with 10% hydrogen peroxide (G1) and 35% hydrogen peroxide (G2). The color stability analysis (CIE color space L* a* b* was performed with Vita Easyshade Compact spectrophotometer before bonding (T0), after aging and staining processes (T1) and after bleaching treatment (T2). All teeth were stored in distilled water at 37°C between experimental times. The comparison between the groups and time effect evaluation were performed using ANOVA / Tukey ( =0.05) and ANOVA-MR with Bonferroni correction ( =0.016), respectively. Results: The color stability parameters L *, a * and b * indicated, with the exception of GC, a tendency of increase in T1 (G1 - L *: 76.72 ± 13.39; a *: 6.68 ± 3.71; b *: 43.14 ± 4.04 / G2: - L *: 75.78 ± 4.66; a *: 8.13 ± 2.75; b *: 43.42 ± 8.87), which reflected the tendency to decrease brightness in T1, followed by a tendency to return to T0 values (G1 - L *: 82.92 ± 12.16; a *: 4.25 ± 3.68; b *: 39.40 ± 9.49 / G2: - L *: 83.76 ± 8.02; a *: 8.76 ± 4.08; b *: 47.90 ± 5.88). Significant differences were observed in G2 in a * (T1: 8.13 ± 2.75, T2: 8.76 ± 4.08) and b * (T1: 43.42 ± 8.87; T2: 47.90 ± 5.88), indicating that this group did not return to the values presented in T0 (a *: 1.81 ± 1.70; b *: 35.40 ± 5.08) (p <0.05). Conclusion: Based on the results of this study, it can be concluded that home bleaching protocol presented better performance for dental surface whitening in an eventual staining after orthodontic debonding.

Objetivo: O objetivo deste estudo foi comparar a eficácia de dois protocolos de tratamento clareador para manchas dentárias causadas após a descolagem ortodôntica. Materiais e Métodos: Vinte e quatro dentes bovinos foram submetidos à colagem e descolagem de braquetes ortodônticos (Morelli, Prescrição Edgewise, Slot 22") (Transbond XT, 3M), que foram divididos em três grupos de acordo com o protocolo de clareamento: peróxido de hidrogênio 10% (Whiteness, FGM) simulando protocolo de clareamento caseiro (grupo clareamento caseiro), peróxido de hidrogênio 35% Whiteness, FGM) simulando protocolo de clareamento de consultório (grupo clareamento de consultório) e Grupo Controle, que não foi exposto a nenhum protocolo de clareamento dental, armazenado em água destilada a 37ºC. Os corpos de prova foram submetidos aos seguintes processos: envelhecimento das resinas remanescentes por ultravioleta (UV), manchamento em solução de café e clareamento dental com peróxido de hidrogênio 10% (G1) e peróxido de hidrogênio 35% (G2). A análise de estabilidade de cor (sistema CIE L* a* b*) foi realizada com espectrofotômetro Vita Easyshade Compact antes da colagem (T0), após os processos de envelhecimento e manchamento (T1) e após o tratamento clareador (T2). Todos os dentes foram armazenados em água destilada a 37 °C entre os tempos experimentais. A comparação entre os grupos e a avaliação do efeito do tempo foram realizadas utilizando ANOVA/Tukey ( =0,05) e ANOVA-MR com correção de Bonferroni ( =0,016), respectivamente. Resultados: Os parâmetros de estabilidade de cor L *, a* e b* indicaram, com exceção do GC, tendência de aumento em T1 (G1 - L*: 76,72 ± 13,39; a*: 6,68 ± 3,71; b*: 43,14 ± 4,04 / G2: - L* : 75,78 ± 4,66; a*: 8,13 ± 2,75; b*: 43,42 ± 8,87), o que refletiu a tendência de diminuição do brilho em T1, seguido de uma tendência de retorno aos valores de T0 (G1- L*: 82,92 ± 12,16 ; a*: 4,25 ± 3,68; b*: 39,40 ± 9,49 / G2: - L*: 83,76 ± 8,02; a*: 8,76 ± 4,08; b*: 47,90 ± 5,88). Foram observadas diferenças significativas no G2 em a* (T1: 8,13 ± 2,75, T2: 8,76 ± 4,08) e b* (T1: 43,42 ± 8,87; T2: 47,90 ± 5,88), indicando que esse grupo não retornou aos valores apresentados em T0 (a*: 1,81 ± 1,70; b*: 35,40 ± 5,08) (p<0,05). Conclusão: Com base nos resultados deste estudo, pode-se concluir que o protocolo de clareamento caseiro apresentou melhor desempenho para o clareamento da superfície dentária em um eventual manchamento após a descolagem ortodôntica.

Dentofacial and skeletal pattern in African descendants from southeastern Brazil: clinical prospective study

ABSTRACT Objective: The aim of this study was to evaluate characteristics of African-Brazilians young adults with excellent dental occlusion, including bimaxillary protrusion; compare them to European-American Caucasian standards, and determine whether there is sexual dimorphism in the display of this phenotype. Methods: Lateral cephalometric radiographs were obtained from 43 African-Brazilians within military personnel (28 males and 15 females, average age 22.4 ± 3.4 years) with normal occlusion, selected from a group of 394 volunteers. Thirty-one angular and linear measurements were evaluated. Student's t-test for independent samples was used to compare results with those established by European-American standards, previously described in the literature. Results: Considering the dentoalveolar pattern, seven angular and six linear measurements showed statistically significant differences (p< 0.001) when compared to Caucasian cephalometric standards. African-Brazilians' subjects showed lower cranial base angle (SNAr = 119.87 ± 5.66º) and anterior cranial base length (SN-distance = 68.63 ± 4.50 mm) (p< 0.001). The maxilla (SNA = 88.51 ± 3.23º) and the mandible (SNB = 85.06 ± 3.24º) were protruded in relation to the SN line (p< 0.001). Sexual dimorphism was significant for L1.NB (degrees) (p< 0.01), and interincisal angle (U1.L1) (p< 0.05). Conclusion: African-Brazilian young adults presented differences regarding dental and craniofacial characteristics, when compared to European-American norms. It can be stated that Caucasian cephalometric norms should not be applied to African-Brazilian faces.

RESUMO Objetivo: O objetivo do presente estudo foi avaliar características de jovens adultos afro-brasileiros com oclusão excelente, incluindo protrusão bimaxilar, e compará-los com os padrões caucasianos europeu-americanos, para determinar se há dimorfismo sexual na exibição desse fenótipo. Métodos: Radiografias cefalométricas laterais foram obtidas de 43 afro-brasileiros militares (28 homens e 15 mulheres, idade média de 22,4 ± 3,4 anos) com oclusão normal, selecionados de um grupo de 394 voluntários. Foram avaliadas 31 medidas angulares e lineares. O teste t de Student para amostras independentes foi utilizado para comparar os resultados com os estabelecidos pelos padrões caucasianos europeu-americanos, descrito previamente na literatura. Resultados: Considerando o padrão dentoalveolar, sete medidas angulares e seis lineares apresentaram diferenças estatisticamente significativas (p< 0,001) quando comparadas aos padrões cefalométricos caucasianos. Sujeitos afro-brasileiros apresentaram menor ângulo da base do crânio (SNAr = 119,87 ± 5,66º) e comprimento da base craniana anterior (distância SN = 68,63 ± 4,50 mm) (p< 0,001). A maxila (SNA = 88,51 ± 3,23º) e a mandíbula (SNB = 85,06 ± 3,24º) estavam protruídas em relação à linha SN (p< 0,001). O dimorfismo de sexo foi significativo para L1.NB (graus) (p< 0,01) e ângulo interincisal (U1.L1) (p< 0,05). Conclusão: Jovens adultos afro-brasileiros apresentaram diferenças em relação às características dentárias e craniofaciais, quando comparados às normas europeias-americanas. Pode-se afirmar que as normas cefalométricas caucasianas não devem ser aplicadas às faces de indivíduos afro-brasileiros.