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Objective The aim of this study was to evaluate dentoskeletal changes in the treatment of Class II malocclusion with the Herbst Cantilever Bite Jumper (CBJ) appliance, associated with multibracket appliances after the growth peak, at pretreatment. Materials and Methods A sample of 37 individuals was divided into two groups: the experimental group comprised 16 patients treated consecutively for a mean period of 2.52 years with the Herbst CBJ appliance associated with multibracket appliances. A total of 21 subjects (10 males and 11 females) with Class II malocclusion and mean age at T1 of 16.08 years were followed for a mean period of 2.12 years composed the control group. Comparisons between the two groups were performed using initial and final lateral cephalograms. Comparisons between experimental and control groups at pretreatment and of the treatment changes were performed by Mann–Whitney or independent t-tests. Results Experimental group exhibited a significantly greater labial inclination of the mandibular incisors in comparison to the control group. Additionally, significantly greater corrections in overbite, overjet, and molar relationship were observed in the experimental than in the control groups. Conclusion The effects of the Herbst CBJ appliance, associated with fixed appliances after the growth peak in Class II malocclusion treatment are correction in molar relationship toward a Class I relationship, decrease of the overjet, decrease of the overbite, and mandibular incisors labial inclination.

The aim of this study was to evaluate the possible effect of low intensity pulsed ultrasound (LIPUS) on tooth movement and root resorption in orthodontic patients. Twenty-one patients were included in a split-mouth study design (group 1). Ten additional patients were included with no LIPUS device being used and this group was used as the negative control group (group 2). Group 1 patients were given LIPUS devices that were randomly assigned to right or left side on upper or lower arches. LIPUS was applied to the assigned side that was obtained by randomization, using transducers that produce ultrasound with a pulse frequency of 1.5 MHz, a pulse repetition rate of 1 kHz, and average output intensity of 30 mW/cm2. Cone-beam computed tomography (CBCT) images were taken before and after treatment. The extraction space dimensions were measured every four weeks and root lengths of canines were measured before and after treatment. The data were analyzed using paired t-test. The study outcome showed that the mean rate of tooth movement in LIPUS side was 0.266 &plusmn, 0.092 mm/week and on the control side was 0.232 &plusmn, 0.085 mm/week and the difference was statistically significant. LIPUS increased the rate of tooth movement by an average of 29%. For orthodontic root resorption, the LIPUS side (0.0092 &plusmn, 0.022 mm/week) showed a statistically significant decrease as compared to control side (0.0223 &plusmn, 0.022 mm/week). The LIPUS application accelerated tooth movement and minimized orthodontically induced tooth root resorption at the same time.

Objectives: To describe qualitatively and quantitatively the directions and magnitudes of rotations of permanent maxillary central incisors and first molars in the mixed dentition in repaired complete unilateral cleft lip and palate (UCLP) and study their associations with absence of teeth in their vicinity. Materials and Methods: Dental casts and orthodontic records taken prior to orthodontic preparation for alveolar bone grafting of 74 children with repaired UCLP (53 male, 21 female; aged 8.9 ± 1.0 years) were studied. Directions and magnitudes of permanent maxillary central incisor and first molar rotations were recorded. Tooth absence was confirmed from longitudinal radiographic records. Incisor and molar rotations were analyzed in relation to the absence of teeth in their vicinity. Results: Distolabial rotation of the permanent maxillary central incisor was noted in 77.14% on the cleft side, while distopalatal rotation was noted in 82.19% on the noncleft side. Incisor rotation was greater when a permanent tooth was present distal to the cleft side central incisor, in the greater segment. The permanent maxillary first molar showed mesiopalatal rotation, which was greater on the cleft side and when there was absence of one or more teeth in the buccal segment. Conclusions: Presence and absence of teeth were associated with the severity of incisor and molar rotations in UCLP. Crowding of anterior teeth in the greater segment was associated with a greater magnitude of rotation of the cleft side permanent central incisor. Absence of one or more buccal segment teeth was associated with greater magnitude of rotation of the molar.

Objective: To compare the mixed dentition incisor and molar overjet, severity of contraction of the dental arch, and the sagittal molar relationship on the cleft side vs the noncleft side in children with repaired complete unilateral cleft of the lip and palate (UCLP). Materials and Methods: Orthodontic records taken prior to orthodontic preparation for alveolar bone grafting were screened to select study casts from patients with nonsyndromic repaired complete UCLP who did not have mandibular skeletal or dental asymmetry. The study sample comprised dental casts from 74 children aged 8.9 ± 1 years. Standardized digital photographs were acquired at 1:1 magnification. A coordinate system was developed using digital image-processing software (Photoshop CS4 and Adobe Illustrator). Incisor and molar overjet, Angle's classification, and arch contraction were recorded. Descriptive statistics, paired t-tests, and kappa statistics were used to compare the cleft and noncleft sides. Results: A negative overjet of −1 to −5 mm was often present at the incisors, with greater frequency and magnitude on the cleft side. Class II molar relation was more frequent on the cleft side (61.1%) than on the noncleft side (47.2%). Significantly greater contraction of the cleft side deciduous canine and deciduous first molar was noted, while the difference was very minor at the first permanent molar. Conclusions: Cleft side maxillary arch contraction was most severe in the deciduous canine and first deciduous molar region and progressively less severe in the posterior region of the arch. A greater frequency and severity of negative overjet and Class II molar relationship was seen on the cleft side.

Objective Maxillary growth in patients with cleft lip and palate is highly variable. The authors' aim was to investigate associations between preoperative cleft lip measurements and maxillary growth determined cephalometrically in patients with complete unilateral cleft lip and palate (cUCLP). Design Retrospective cross-sectional study. Patients Children with cUCLP. Methods Preoperative cleft lip measurements were made at the time of primary cheiloplasty and available for each patient. Maxillary growth was evaluated on lateral cephalometric radiographs taken prior to any orthodontic treatment and alveolar bone grafting (8.5 ± 0.7 years). The presence of associations between preoperative cleft lip measurements and cephalometric measures of maxillary growth was determined using regression analyses. Results In the 58 patients included in the study, the cleft lateral lip element was deficient in height in 90% and in transverse width in 81% of patients. There was an inverse correlation between cleft lateral lip height and transverse width with a β coefficient of −0.382 ( P = .003). Patients with a more deficient cleft lateral lip height displayed a shorter maxillary length (β coefficient = 0.336; P = .010), a less protruded maxilla (β coefficient = .334; P =.008), and a shorter anterior maxillary height (β coefficient = 0.306; P = .020) than those with a less deficient cleft lateral lip height. Conclusions Patients with cUCLP present with varying degrees of lateral lip hypoplasia. Preoperative measures of lateral lip deficiency are related to later observed deficiencies of maxillary length, protrusion, and height.

Purpose The purpose of this study was to evaluate the maxillary incisors position and soft-tissue characteristics of Class II, division 1 patients treated with non-extraction, 2-maxillary and 4-premolar extraction protocols. Materials and methods The sample of 120 subjects was divided into four groups. The first three treated groups presented Class II, division 1 malocclusion patients. G1 comprised 30 patients (14.95 years), and was treated without extraction. G2 comprised 30 patients (15.28 years), treated with extraction of 2-maxillary premolars. G3 consisted of 30 patients (15.55 years), treated with extraction of 4-premolars, and G4 included 30 individuals (14.93 years) with normal occlusion. The occlusal features of the treated groups were evaluated by the Peer Assessment Rating (PAR) index and the cephalometric characteristics were compared with ANOVA. Results The maxillary incisors were similarly positioned among the treated groups at the end of treatment. However, they were more upright in G2 and G3 than in the control group (G4). The hard- and soft-tissue cephalometric characteristics were similar in all groups. Conclusion Class II treatment conducted non-extraction, with 2-maxillary and with 4-premolar extraction protocols showed similar effects on final maxillary incisors positioning and nasolabial angle. In general, the 4-premolar extraction protocol was potentially more retrusive, but the dentofacial differences were slight and not statistically significant.

Objective To investigate the stability of major versus minor Le Fort I maxillary advancements in unilateral cleft lip and palate (UCLP) patients. Design A retrospective longitudinal study was undertaken on 30 nonsyndromic UCLP patients treated with the same protocol at The Hospital for Sick Children, Toronto, Canada. Patients were grouped into major and minor movement groups based on planned surgical advancement. Standard lateral cephalometric radiographs were taken preoperatively (T1), immediately postoperatively (T2), and at least 1 year postoperatively (T3). Skeletal and dental variables were measured using cephalometric analysis. Stability was compared between groups using repeated-measures analysis of variance. Linear regression analysis was used to assess the relationship between advancement and relapse for the entire study population. Results A mean maxillary advancement of 9.8 mm and 4.9 mm was seen for the major (n = 10) and minor (n = 20) movement groups, respectively. The mean skeletal horizontal relapse was 1.8 mm (18%) for the major advancement group and 1.5 mm (31%) for the minor advancement group. There was no significant difference in skeletal horizontal relapse between the groups ( P > .05). The correlation coefficient ( r) between linear horizontal advancement and relapse was calculated to be .31 ( P > .05). Dental horizontal relapse was not significant for either the major or minor groups, and no significant difference was found between the groups ( P > .05) Conclusion Skeletal and dental relapse was found to be unrelated to the amount of maxillary linear advancement using conventional Le Fort I osteotomies in UCLP.

Objective: To compare posttreatment and postretention occlusal changes with the physiologic occlusal changes caused by natural development of untreated subjects. Materials and Methods: The sample was divided into three groups. Group 1 comprised 97 subjects treated with four premolar extractions at a mean pretreatment (T0) age of 13.03 years, a mean posttreatment (T1, first observation) age of 15.12 years, and a mean postretention (T2, second observation) age of 20.52 years. The mean observation period (T2-T1) was 5.39 years. Group 2 comprised 58 subjects treated nonextraction at a mean pretreatment age of 12.83 years, a mean posttreatment age of 14.99 years, a mean postretention age of 20.22 years, and a mean observation period of 5.22 years. Group 3 comprised 114 untreated subjects at a mean age at T1 of 14.91 years and at T2 of 20.48 years. The mean observation period was 5.56 years. Dental casts were evaluated using the Peer Assessment Rating (PAR) index and the Little irregularity index in maxillary and mandibular arches. Changes in PAR and Little indexes were compared among the three groups by analysis of variance and Tukey tests. Results: Intergroup comparison showed that at T1 and T2 the treated groups presented smaller PAR and Little indexes than the untreated group. In the observation period, the treated groups showed greater increase in PAR and Little maxillary indexes than the untreated group. The extraction group showed a greater increase of the Little mandibular index than the untreated group. Conclusions: The treated groups showed more changes according to PAR and Little maxillary indexes than the untreated group. The posttreatment change of the mandibular anterior crowding of the treated extraction group was greater than the mandibular crowding caused by physiologic changes in the untreated group.

Objective: To elucidate some of the parameters determining the frictional behavior of passive, active, and interactive self-ligating brackets during sliding mechanics. Materials and Methods: A custom jig mimicking the three-dimensional tooth movements that occur during sliding mechanics and an Instron testing machine were used to determine the resistance to sliding of six different self-ligating brackets (SPEED, In-Ovation C, CarriereSLB, ClaritySL, SmartClip, VisionLP). Each bracket was tested on three rectangular stainless steel wires: 0.017 3 0.022 inch, 0.017 3 0.025 inch, and 0.019 3 0.025 inch. A two-way balanced analysis of variance was used for statistical analysis. Results: The four passive self-ligating brackets (CarriereSLB, ClaritySL, SmartClip, VisionLP) displayed significantly lower frictional resistance (P , .001) than the remaining brackets, which featured an active (SPEED) or interactive (In-Ovation C) clip. The SPEED bracket consistently demonstrated the highest resistance to sliding. Conclusions: The mode of self-ligation appears to be the primary variable in determining the frictional behavior of orthodontic brackets undergoing sliding mechanics. Passive self-ligating brackets demonstrated significantly lower frictional resistance to sliding. With regard to the resistance of active self-ligating brackets, the depth (buccolingual thickness) of the wire had a more significant influence than its height. (Angle Orthod. 2011;81:1036-1044.)

SUMMARY The objective of this investigation was to assess and compare the in vitro tribological behaviour of four commercially available self-ligating bracket systems. The frictional characteristics of the Damon3 ™ , Speed ™ , In-Ovation R ™ , and Time2 ™ bracket systems were studied using a jig that mimics the three-dimensional movements that occur during sliding mechanics. Each bracket system was tested on the following stainless steel archwires: 0.016 × 0.022, 0.019 × 0.025, 0.020 round , and 0.021 × 0.021 inch Speed ™ D-wire. An Instron testing machine with a 50 N load cell was used to measure the frictional resistance for each bracket/tooth assembly. The crosshead speed was set at a constant rate of 1 mm/minute, and each typodont tooth was moved along a fi xed wire segment for a distance of 8 mm. Descriptive statistical analysis for each bracket/archwire combination with regard to frictional resistance was performed with a two-way, balanced analysis of variance for bracket type and wire size. The Damon3 ™ bracket consistently demonstrated the lowest frictional resistance to sliding, while the Speed ™ bracket produced signifi cantly ( P < 0.001) more frictional resistance than the other brackets tested for any given archwire. The self-ligation design (passive versus active) appears to be the primary variable responsible for the frictional resistance generated by self-ligating brackets during translation. Passively ligated brackets produce less frictional resistance; however, this decreased friction may result in decreased control compared with actively ligated systems.

OBJECTIVE: To determine compliance with oral hygiene instructions (OHI) of adolescents receiving two-arch multibracket fixed appliances and identify its predictive factors. MATERIALS AND METHODS: Forty-one patients in a longitudinal study were provided standardized OHI and assessed at baseline: before bonding (T0mo), approximately 30 days after bonding (T1mo), and approximately 150 days (T5mo) after bonding straight-wire appliances simultaneously in the maxillary and mandibular arches. Oral hygiene (OH) performance was measured using plaque and gingival indices. Compliance predictors were identified from questionnaires administered to patients and their parents and from patients' charts. RESULTS: OH performance worsened from T0mo to T1mo but then improved from T1mo to T5mo. At T5mo, 73% of the sample had good OH. Univariate analyses found perceived severity of malocclusion, school performance, and parental marital status to be significant predictors of good OH performance at T5mo. Multiple logistic regressions identified having married parents and good academic performance in school as significant predictors. CONCLUSIONS: In the sample studied, after initially worsening, compliance with OHI improved at 5 months after bonding. Adolescents with married parents and those reporting good academic performance in school were found more likely to have complied with OHI provided at baseline and to perform better OH.

Objective: To (1) document the prevalence and patterns of hypodontia (permanent tooth agenesis) in Down syndrome (DS) and (2) explore whether maxillary or mandibular hypodontia or simultaneous agenesis of all third molars was associated with differential alterations of the craniofacial morphology. Materials and Methods: Longitudinal panoramic radiographs of 25 white patients with DS (12 male, 13 female; mean age, 15.1 years) treated at The Hospital for Sick Children, Toronto, Ontario, Canada, were evaluated to document hypodontia. Cephalometric measurements of subjects with maxillary or mandibular hypodontia or agenesis of all third molars were compared with those of subjects without hypodontia in these regions using analysis of covariance adjusted for age, gender, and proportion of other missing teeth in the total number of missing teeth. Results: Hypodontia was seen in 92% of the sample when third molars were considered and in 56% when third molars were not considered. Hypodontia was more prevalent and severe in females. The most frequently agenetic teeth were maxillary and mandibular third molars . maxillary lateral incisors . mandibular second premolars . mandibular incisors . maxillary second premolars . maxillary second molars. Simultaneous agenesis of all third molars was seen in 52% of the sample. Maxillary hypodontia was not associated with significant regional craniofacial differences, while mandibular hypodontia was associated with decreased mandibular length and increased ramus:body ratio. Agenesis of all third molars was not associated with significant craniofacial differences. Conclusions: Hypodontia is widely prevalent in DS. The effect of the syndrome appears to be stronger than that of regional hypodontia in differentially altering the craniofacial morphology. (Angle Orthod. 2011;81:260–269.)

OBJECTIVE: To test the null hypothesis that there is no difference between craniofacial measurements of individuals with Down syndrome (DS) and normal controls. MATERIALS AND METHODS: A cephalometric analysis including additional landmarks and measurements to study specific craniofacial features was undertaken on pretreatment cephalograms of 25 patients with DS (12 male, 13 female; mean age 15.1 years) treated at The Hospital for Sick Children, Toronto. Measurements were compared with those from cephalograms of racial groups age and gender matched, normal, Class I children, available from the Burlington Growth Center. Data were analyzed using paired t-tests. RESULTS: Large reductions were measured in the size and spatial relationships of craniofacial structures in the DS group. The greatest differences included a larger cranial base angle; reduced elevation of sella from FHP; reduced anterior and posterior cranial base lengths; reduced anterior and posterior face heights; smaller maxilla with reduced anterior basal and apical dimensions; and smaller mandibular ramus, body and symphyseal dimensions and proclined symphysis. Maxillary incisors were severely proclined and undererupted, while mandibular incisors were undererupted. Alveolar heights were reduced. Anterior open bite was frequently noted. Maxillary and mandibular planes exhibited forward rotation patterns, promoting overclosure. Mandibular hypoplasia was less severe than cranial base and maxillary hypoplasia. Hypodontia of one or more permanent teeth was found in 92% of the sample. CONCLUSIONS: The null hypothesis was rejected. Significant hypoplasia in endochondral, mesodermal, and ectomesenchymal derived structures of the cranium and face in subjects with DS was clearly evident. More severe platybasia than previously reported was found.

Introduction The aim of this study was to investigate the prevalence of tooth wear in adolescents with Class II malocclusion, compared with those with normal occlusion. Methods The sample consisted of dental casts obtained from 310 subjects, divided into 3 groups: group 1, 110 subjects with normal occlusion (mean age, 13.51 years); group 2, 100 complete Class II Division 1 patients (mean age, 13.44 years); and group 3, 100 half-cusp Class II Division 1 patients (mean age, 13.17 years). Dental wear was assessed by using a modified version of the tooth-wear index. The 3 groups were compared by means of the Kruskal-Wallis and Dunn tests, considering the frequency and the severity of wear on each surface of each group of teeth. The level of statistical significance was set at 5%. Results The normal occlusion group had statistically greater tooth wear on the palatal surfaces of the maxillary central incisors and the incisal surfaces of the maxillary canines than the corresponding surfaces in both Class II malocclusion groups. The complete and half-cusp Class II Division 1 malocclusion groups had statistically greater tooth wear on the occlusal surfaces of the maxillary second premolar and first molar, the occlusal surfaces of the mandibular premolars, and the buccal surfaces of the mandibular posterior teeth compared with the normal occlusion group. The half-cusp Class II Division 1 malocclusion group had significantly greater tooth wear on the incisal surfaces of the mandibular incisors compared with the complete Class II Division 1 malocclusion group. Conclusions Subjects with normal occlusion and complete or half-cusp Class II Division 1 malocclusions have different tooth-wear patterns. Tooth wear on the malocclusion subjects should not be considered pathologic but rather consequent to the different interocclusal tooth arrangement.

OBJETIVO: Realizou-se um estudo cefalométrico, em telerradiografias, objetivando-se determinar os efeitos no complexo craniofacial de pacientes com más oclusões de Classe II, divisão 1 submetidos ao tratamento com o aparelho de Herbst com cantiléver. METODOLOGIA: Para tanto, utilizou-se uma amostra composta por dois grupos, sendo um experimental e um controle. O grupo experimental originou-se da Faculdade de Odontologia de Bauru - USP, com 25 pacientes tratados com o aparelho ortopédico funcional e a idade inicial média de 12,01 anos. O grupo de controle, pareado cronologicamente ao grupo experimental, foi composto por pacientes não tratados ortodonticamente e/ou ortopedicamente, oriundos do arquivo de documentações denominado Burlington Growth Centre, localizado na Faculdade de Odontologia da Universidade de Toronto, Canadá. Para cada componente dos dois grupos, obtiveram-se as telerradiografias ao início (T1) e ao final (T2) do período de tratamento ou de observação, sendo traçadas manualmente e digitalizadas para um programa de cefalometria. Foram estabelecidas 33 grandezas cefalométricas. RESULTADOS E CONCLUSÕES: A comparação estatística entre o grupo experimental e o grupo controle (teste t de Student, com nível de significância p