Comparison of dental outcomes in patients with nonsyndromic complete unilateral cleft lip and palate who receive secondary alveolar bone grafting before or after emergence of the permanent maxillary canine.

INTRODUCTION: For patients with complete unilateral cleft lip and palate (CUCLP), secondary alveolar bone grafting (SABG) can be performed before or after the emergence of the cleft side permanent canine (pre-CE and post-CE, respectively). The controversy regarding dental outcomes related to the timing of SABG remains unsettled. The objective of this study was to evaluate dental survival and specific dental outcomes of cleft-adjacent teeth in children with CUCLP who received either pre-CE or post-CE SABG. METHODS: The permanent maxillary canines and the central and lateral incisors of 21 pre-CE and 23 post-CE SABG subjects with nonsyndromic CUCLP and all cleft-related surgeries performed by the same surgeon were analyzed retrospectively. Intraoral radiographs and clinical chart notes were collected at age 7 years, at the time of the SABG, and approximately 4 years after the grafting. Dental survival, spontaneous canine eruption, planned prosthetic replacement, root development, and root resorption were analyzed. RESULTS: Dental outcomes on the noncleft side were better than those on the cleft side. On the cleft side, dental survival of the cleft-adjacent teeth was not significantly different between the pre-CE and post-CE SABG groups (P >0.05). Most teeth completed root development after grafting, and the cleft side canine root development in the pre-CE SABG group appeared to accelerate after SABG. Trends showed that the pre-CE SABG group suffered less root resorption (16.28%; post-CE: 22.73%; P >0.05) and received fewer planned prosthetic replacements (14.29%; post-CE: 26.01%; P >0.05) but required a greater number of canine exposures (33.33%; post-CE: 4.55%; P = 0.02). CONCLUSIONS: Pre-CE SABG showed better dental outcomes in patients with CUCLP, with fewer adverse dental outcomes than post-CE SABG.

Effects of orthodontic appliances on the diagnostic quality of magnetic resonance images of the head.

INTRODUCTION: The influence of 4 commonly used fixed orthodontic appliances on artifact formation and diagnostic quality of magnetic resonance (MR) images of the head produced by a 3-T MR scanner was studied. METHODS: Stainless steel brackets, ceramic brackets, combination of ceramic brackets and steel molar tubes, and multistranded steel mandibular lingual retainers were embedded into custom-made trays for each of 10 adult subjects. Head MR scans of 9 regions were acquired for each subject wearing these trays. Sagittal T1-weighted, axial T2-weighted, axial gradient-recalled, axial diffusion-weighted, noncontrast axial MR angiography, and axial fluid-attenuated inversion recovery MR sequences were included. Two neuroradiologists evaluated image distortions and diagnostic qualities of the 1314 acquired images (13860 image slices). RESULTS: The images were affected by appliance, head region, and MR sequence. Stainless steel brackets and molar tubes affected the images the most, and ceramic brackets caused minimal image distortion. CONCLUSIONS: Head MR images are differentially affected by orthodontic appliances. The appliance, region imaged, and MR sequence should be considered before imaging patients wearing fixed orthodontic appliances.

Preoperative Cleft Lip Measurements and Maxillary Growth in Patients With Unilateral Cleft Lip and Palate.

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 ß coefficient of -0.382 (P = .003). Patients with a more deficient cleft lateral lip height displayed a shorter maxillary length (ß coefficient = 0.336; P = .010), a less protruded maxilla (ß coefficient = .334; P = .008), and a shorter anterior maxillary height (ß 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.

Presurgical cleft lip anthropometrics and dental arch relationships in patients with complete unilateral cleft lip and palate.

OBJECTIVE: To investigate associations between anthropometric lip measurements and dental arch relationships in patients with complete unilateral cleft lip and palate (CUCLP). DESIGN: Retrospective cross-sectional study. PATIENTS: Children with CUCLP. METHODS: Anthropometric lip measurements, made immediately prior to lip repair, were available for each patient. The dental arch relationships were evaluated on dental study casts (8.6 ± 0.9 years) taken prior to any orthodontic treatment and prior to alveolar bone graft, using the modified Huddart and Bodenham (MHB) scoring system. The presence of associations between anthropometric lip measurements and dental arch relationships was determined using linear regression analysis. RESULTS: In the 63 patients included in the study, the cleft lateral lip element was deficient in height in 87% and in transverse width in 86% of patients. Patients with more deficient cleft-side lateral lip height were more likely to present with more negative MHB scores (r = .443; P < .001). Conversely, patients with more deficient cleft-side lateral lip transverse width more often presented with more positive MHB scores (r = .281; P = .025). CONCLUSIONS: In patients with CUCLP, there is a wide variability in the degree of deficiency of the cleft-side lateral lip element, both in the vertical and in the transverse dimension. The extent of this deficiency may, in part, predict the resulting dental arch relationships.

Is Linear Advancement Related to Relapse in Unilateral Cleft Lip and Palate Orthognathic Surgery?

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.

The effect of light emitting diode phototherapy on rate of orthodontic tooth movement: a split mouth, controlled clinical trial.

OBJECTIVE: Increasing the rate of orthodontic tooth movement (OTM) can reduce risks such as periodontal disease and caries. TRIAL DESIGN: This split-mouth randomized controlled clinical trial investigated whether light emitting diode (LED) phototherapy could accelerate the rate of OTM. SETTING: The study was conducted at the Graduate Orthodontics Clinic at the University of Toronto, Faculty of Dentistry. PARTICIPANTS AND METHODS: 17 dental arches from 11 orthodontic participants with bilaterally symmetrical extraction of premolars were included. During space closure of single tooth extraction sites, LED phototherapy was applied to one side of the dental arch for a specified time and the contralateral side acted as the control. Space closure was measured immediately prior to, during and later in space closure. RESULTS: All participants were compliant with LED application. Our results revealed no significant changes in the rate of OTM with LED phototherapy over 3 months of extraction space closure. CONCLUSIONS: Our findings were contrary to previous findings of the effect of laser phototherapy on regulating the rate of OTM. Further investigations are warranted to analyse whether the duration or method of LED delivery would have an effect on the rate of OTM. Toronto. This trial was registered at clinicaltrials.gov (NCT01490385).

Single versus segmental maxillary osteotomies and long-term stability in unilateral cleft lip and palate related malocclusion.

PURPOSE: To investigate the stability of single-piece versus segmental (2-piece) maxillary advancement in patients with unilateral cleft lip and palate (UCLP) treated using conventional Le Fort I orthognathic surgery. PATIENTS AND METHODS: A retrospective study was undertaken in 30 patients with nonsyndromic UCLP treated with the same surgical and orthodontic protocol from 2002 through 2011. Standard lateral cephalometric radiographs were taken preoperatively, immediately postoperatively, and at least 1 year postoperatively. Patients were divided into single-piece and segmental Le Fort I groups based on planned surgical movement. Postoperative movements were compared between groups using repeated measures analysis of variance. RESULTS: The mean skeletal horizontal advancement was 7.3 and 7.5 mm in the single-piece and segmental groups, respectively. The skeletal horizontal relapse was 1.3 mm (18%) for the single-piece group and 1.9 mm (25%) for the segmental group. The skeletal surgical extrusion was 2.7 mm for the 2 groups. The skeletal vertical relapse was 0.6 mm (22%) and 1.5 mm (56%) for the single-piece and segmental groups, respectively. The mean dental horizontal postoperative movement was an advancement of 0.4 mm for the single-piece group and a relapse of 0.2 mm (3%) for the segmental group. The mean dental vertical relapse was 0.1 mm (4%) for the single-piece group and 0.3 mm (11%) for the segmental group. There was no statistically significant difference in relapse between the single-piece and segmental groups for all movements (P>.05). CONCLUSION: Skeletal and dental relapse was similar between single-piece and segmental maxillary advancements using conventional Le Fort I orthognathic surgery in patients with UCLP.

Cephalometric outcomes of orthognathic surgery in hemifacial microsomia.

Hemifacial microsomia is a hypoplastic disorder of the first and second branchial arches that significantly impacts on the development of the jaws, leading to malocclusion and facial asymmetry. There is little in the literature regarding the application of orthodontic/orthognathic approaches to the correction of these deformities and the stability of the surgical results. To address this, a retrospective chart review of 10 patients with complete orthodontic records and greater than 1 year of follow-up was performed. Posteroanterior cephalograms were assessed by modified Grummons analysis to determine mandibular offset (deviation of the chin point from the skeletal midline) and occlusal cant. These measurements were performed at 3 time points (T1: preoperative, T2: immediate postoperative, T3: follow-up) to elucidate the surgical movement (T2-T1), the postoperative relapse (T3-T2), and the net gain movement (T3-T1). Maxillary movements were quantified, and the occlusal cant was expressed as a ratio between vertical heights of the maxilla at the first molar on each side. One sample t test demonstrated statistically significant surgical movement and net gain. Relapse was statistically insignificant. Repeated-measures analysis of variance demonstrated similar results for chin point position relative to the putative midline. Our results suggest that a combined orthodontic/orthognathic approach at skeletal maturity delivers improved occlusal outcomes in the long term as assessed by chin point deviation and occlusal cant, but secondary surgery rates are higher than those for orthognathic surgery in other patient groups. We advocate limiting surgery to skeletal maturity whenever possible to achieve stable long-term results while limiting morbidity and number of procedures.

Soft-tissue profile growth in patients with repaired complete unilateral cleft lip and palate: A cephalometric comparison with normal controls at ages 7, 11, and 18 years.

INTRODUCTION: In this retrospective longitudinal study, we aimed to study differences in the soft-tissue profiles in growing children with clefts in comparison with controls through the period of facial growth from 7 to 18 years. METHODS: Lateral cephalometric measurements made at 7 years (T1), 11.1 years (T2), and 17.9 years (T3) of age of 70 white children (35 boys, 35 girls) with complete unilateral cleft lip and palate (UCLP) who received primary lip and palate repair surgeries at The Hospital for Sick Children, Toronto, were compared with those of a control group of similar ages, sexes, and racial backgrounds, and having skeletal Class I facial growth, selected from the Burlington Growth Study. None of the included subjects had received any surgeries other than the primary lip and palate repairs, and none had undergone nasal septum surgery or nasal molding during infancy. Between-group comparisons were made at each time point using generalized linear models adjusted for age and sex effects. Longitudinal comparisons across all time points were conducted using the mixed model approach, adjusting for these effects and their interactions with time. RESULTS: Bimaxillary retrognathism, progressive maxillary retrognathism, and increasing lower anterior face height with downward and backward growth rotation of the mandible in the UCLP group were seen. Unlike the hard-tissue face height ratio, their soft-tissue face height ratio was not affected. The upper lips in the UCLP group were shorter by 1.81 mm at T2 (P <0.001) and by 1.16 mm at T3 (P = 0.018), whereas their lower lips were 2.21 mm longer at T3 (P = 0.003). A reduced upper lip to lower lip length ratio at T2 and T3 (P <0.001) resulted. Their upper lips were relatively retruded by 1.44 mm at T1, 1.66 mm at T2, and 1.86 mm at T3 (all, P <0.001), and their lower lips were relatively protruded by 1.07 mm at T1 (P = 0.003), 1.40 mm at T2 (P <0.001), and 1.62 mm at T3 (P <0.001). Nose depths in the UCLP group were shallower by at least 1 mm from T1 to T3, and columellar length was shorter by almost 2 mm (all, P <0.001). Their columellae and nose tips rotated downward with growth, with the most significant rotations experienced from T2 to T3, and progressive reductions in their soft-tissue profile convexity were seen from T1 to T3 (P <0.001). CONCLUSIONS: Key attributes of the imbalance in the soft-tissue profile in children with repaired UCLP were identified in the lip and nose regions. Although many profile differences were visible as early as 7 years of age, they became more apparent by 11 years of age and increased in severity thereafter. The short upper lip combined with a long lower lip resulted in the characteristic lip length imbalance, whereas the progressively retruding upper lip and protruding lower lip led to developing a step relationship in the sagittal lip profile during the adolescent growth period. Their columellae and nose tips rotated downward during this time.

Root development differences between cleft-adjacent teeth on the cleft side in comparison to their analogs on the noncleft side in patients with nonsyndromic cleft lip and palate who received secondary alveolar bone grafting.

OBJECTIVE: To assess differences in root development between the cleft side (CS) and noncleft side (NCS) for permanent maxillary central incisor and canine longitudinally in patients with nonsyndromic complete unilateral cleft lip and palate (cUCLP) who received secondary alveolar bone grafting (SABG) and to evaluate the effects of SABG on the acceleration of root development of these teeth. MATERIALS AND METHODS: Permanent maxillary central incisors and canines of 44 subjects with nonsyndromic cUCLP who had all their cleft-related surgeries performed by the same surgeon were analyzed retrospectively from chart notes and radiographs. Panoramic and periapical radiographs at time point 1 (T1) (age, 7.55 years), at SABG (time point 2 [T2], 10.13 years), and a minimum of 2 years after SABG were studied. Root development rating scores on the NCS and CS were compared using paired t-tests and analyses of proportions. RESULTS: Mean root development score differences (NCS - CS) for canines and central incisors were greatest at T2 but diminished at time point 3 (T3). A larger proportion of teeth on the CS trailed the teeth on the NCS by at least 1 point at T2 than at T1 or T3, with the smallest proportion being observed at T3. The change in root development scores from T1 to T2 and from T2 to T3 showed relative CS acceleration from T2 to T3, indicating a catch-up of root development of cleft-adjacent teeth after SABG. CONCLUSIONS: Root development of cleft-adjacent central incisors and canines is slow in comparison with their noncleft analogs. Root development of these teeth accelerates following SABG.

Longitudinal comparison of skeletal age determined by the Greulich and Pyle method and chronologic age in normally growing children, and clinical interpretations for orthodontics.

INTRODUCTION: Coinciding treatment with periods of accelerated skeletal growth and maturation might be advantageous in clinical practice. Better understanding of the concordance between skeletal and chronologic ages during the period that children frequently receive orthodontic treatment is needed. The literature on skeletal age determination from hand-wrist radiographs lacks reports based on longitudinal data, creating lacunae in the understanding of the magnitudes and variations of differences between skeletal and chronologic ages. The aims of this research were to comprehensively analyze the concordance between skeletal and chronologic ages determined by using the Greulich and Pyle method at different ages in the preadolescent and adolescent periods, and to determine any age- and sex-related differences in the concordance. METHODS: By using the Greulich and Pyle method, skeletal age determinations were made from 572 hand-wrist radiographs of 68 white children with normal facial growth, selected from the records of the Burlington Growth Centre, spanning the growth period from 9 to 18 years. Skeletal age and chronologic age differences for each sex were analyzed by using paired t tests and Wilcoxon signed rank tests at yearly intervals. Differences over the longitudinal duration were examined by using the mixed model approach. The limits of agreement were determined by using the Bland-Altman method. In each yearly chronologic age group, differences were clinically categorized based on the proximity of the skeletal and chronologic ages. RESULTS: Overall, a slightly greater proportion of the total skeletal age determinations made in girls (41.9%) were within 0.5 year of their chronologic age, compared with 38% in boys. The largest proportions of subjects having skeletal age-chronologic age differences within 0.5 year were in the 10-year age group in girls (64.5%) and the 13-year age group in boys (64.7%). Mean skeletal age-chronologic age differences were significantly larger in the 13- to 16-year age groups in girls and in the 16- and 17-year age groups in boys, but the differences were not statistically significant at other ages. Several patterns of variations were identified in the direction of differences when individual plots were examined. CONCLUSIONS: This longitudinal analysis of differences between skeletal and chronologic ages showed wide ranges and distributions of differences at each yearly age group during the growth period from 9 to 18 years, even when mean differences were small. Variations in the magnitude and direction of differences observed at different ages highlighted the variability in skeletal maturation among normally growing young people. Overall, the differences in skeletal and chronologic ages were positively related to age, with little effect of sex or its interaction with age.

Effect of alveolar bone grafting on nasal morphology, symmetry, and nostril shape of patients with unilateral cleft lip and palate.

OBJECTIVE: To evaluate nasal morphology, symmetry, and nostril shape in patients with unilateral cleft lip and palate following mixed-dentition alveolar bone grafting. DESIGN: Prospective stereophotogrammetric study. SETTING: Hospital-based. PATIENTS: Thirty-nine patients with a history of repaired unilateral cleft lip and palate who received an iliac crest alveolar bone graft were recruited prospectively to participate in the study. Each patient served as his/her own control. INTERVENTIONS: Partial facial impressions of all patients were acquired before and a minimum of 6 months after the alveolar bone grafting procedure. Image acquisition and analysis of the casts constructed from these models were carried out using three-dimensional stereophotogrammetry. MAIN OUTCOME MEASURES: Surface-based registrations and linear measurements were performed to assess nasal morphology and nostril shape. A modified Procrustes technique was used to determine the change in nasal symmetry. A two-tailed, paired t test and an analysis of covariance were used to assess statistical significance. RESULTS: Significant side-to-side asymmetry exists in the nasal region of patients with unilateral cleft lip and palate, both before and after alveolar bone grafting. No significant changes were observed between pre-alveolar bone graft and post-alveolar bone graft images based on linear measurements, asymmetry scores, and registrations. Gender and surgeon were not significant factors. CONCLUSION: Under the conditions of this study, mixed-dentition alveolar bone grafting appears to have no significant long-term effect on nasal morphology, symmetry, or nostril shape.

Does psychological well-being influence oral-health-related quality of life reports in children receiving orthodontic treatment?

INTRODUCTION: Although the associations between oral biologic variables such as malocclusion and oral-health-related quality of life (OHRQOL) have been explored, little research has been done to address the influence of psychological characteristics on perceived OHRQOL. The aim of this study was to assess OHRQOL outcomes in orthodontics while controlling for individual psychological characteristics. We postulated that children with better psychological well-being (PWB) would experience fewer negative OHRQOL impacts, regardless of their orthodontic treatment status. METHODS: One hundred eighteen children (74 treatment and 44 on the waiting list), aged 11 to 14 years, seeking treatment at the orthodontic clinics at the University of Toronto, participated in this study. The child perception questionnaire (CPQ11-14) and the PWB subscale of the child health questionnaire were administered at baseline and follow-up. Occlusal changes were assessed by using the dental aesthetic index. A waiting-list comparison group was used to account for age-related effects. RESULTS: Although the treatment subjects had significantly better OHRQOL scores at follow-up, the results were significantly modified by each subject's PWB status (P <0.01). Furthermore, multivariate analysis showed that PWB contributed significantly to the variance in CPQ11-14 scores (26%). In contrast, the amount of variance explained by the treatment status alone was relatively small (9%). CONCLUSIONS: The results of this study support the postulated mediator role of PWB when evaluating OHRQOL outcomes in children undergoing orthodontic treatment. Children with better PWB are, in general, more likely to report better OHRQOL regardless of their orthodontic treatment status. On the other hand, children with low PWB, who did not receive orthodontic treatment, experienced worse OHRQOL compared with those who received treatment. This suggests that children with low PWB can benefit from orthodontic treatment. Nonetheless, further work, with larger samples and longer follow-ups, is needed to confirm this finding and to improve our understanding of how other psychological factors relate to patients' OHRQOL.

Impact of a rapid palatal expander on speech articulation.

INTRODUCTION: Rapid palatal expanders (RPEs) have attachments cemented to the teeth and a screw that covers the palate. Because of their position and relative size, RPEs can affect speech. Our objective was to assess speech perturbation and adaptation related to RPE appliances over time. METHODS: RPEs were planned for the treatment of 22 patients in the orthodontic clinic at the University of Toronto in Canada. Speech recordings were made at 6 time points: before RPE placement, after placement, during expansion, during retention, after removal, and 4 weeks after removal. The speech recordings consisted of 35 sentences, from which 3 sentences were chosen for analysis. Speech acceptability was assessed perceptually by 10 listeners who rated each sentence on an equal-appearing interval scale. The vowel formants for /i/ and the fricative spectra for /s/ and /∫/ were measured with speech analysis software. Repeated-measures analysis of variance with post-hoc paired t tests was used for statistical analysis. RESULTS: When the appliance was placed, speech acceptability deteriorated. Over time, the ratings improved and returned to baseline when the appliance was removed. For the vowel /i/, the first formant increased, and the second formant decreased in frequency, indicating centralization of the vowel. The formants returned to the pretreatment levels during treatment. For the fricatives (/s/ and /∫/), low-to-high frequency ratios indicated that the fricatives were distorted when the appliance was placed. The ratios returned to baseline levels once the appliance was removed. The results for the spectral moments indicated that spectral mean decreased and skewness became more positive. Repeated-measures analysis of variance showed significant effects for time for all acoustic measures. CONCLUSIONS: Speech was altered and distorted when the appliance was first placed. The patients' speech gradually improved over time and returned to baseline once the appliance was removed. The results from the study will be useful for pretreatment counseling of patients and their families.

Relationship between cervical vertebral maturation and mandibular growth.

INTRODUCTION: The cervical vertebrae have been proposed as a method of determining biologic maturity. The purposes of this study were to establish a pattern of mandibular growth and to relate this pattern to the stages of cervical vertebral maturation. METHODS: Cephalometric radiographs, taken annually from ages 9 to 18 years, were evaluated for 90 boys from the Burlington Growth Center, Toronto, Ontario, Canada. Mandibular lengths were measured from articulare to gnathion, and incremental growth was determined. Cervical vertebral maturation stages were assessed by using a 6-stage method. Advanced, average, and delayed maturation groups were established. RESULTS: The prepubertal mandibular growth minimum velocity occurred during cervical stages 1 through 4 (P = 0.7327). Peak mandibular growth velocity occurred most frequently during stage 4 in all 3 maturation groups, with a statistical difference in the average and delayed groups (P <0.0001) and the advanced group (P = 0.0143). The average number of years spent in stage 4 was 3.79 (P <0.0001). The average amount of mandibular growth occurring during stage 4 was 9.40 mm (P <0.0001). The average amount of growth in stages 5 and 6 combined was 7.09 mm. CONCLUSIONS: Progression from cervical stages 1 through 6 does not occur annually; time spent in each stage varies depending on the stage and the maturation group. Cervical vertebral maturation stages cannot accurately identify the mandibular prepubertal growth minimum and therefore cannot predict the onset of the peak in mandibular growth. The cervical vertebral maturation stages should be used with other methods of biologic maturity assessment when considering both dentofacial orthopedic treatment and orthognathic surgery.

Treatment Effects of the Herbst Appliance in Class II Malocclusion Patients after the Growth Peak.

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.

Oral health-related quality of life of children with oligodontia.

OBJECTIVES: To assess the functional and psychosocial impact of oligodontia in children aged 11-14 years. METHODS: Children aged 11-14 years with oligodontia were recruited from orthodontic clinics when they presented for orthodontic evaluation. All completed a copy of the Child Perceptions Questionnaire for 11- to 14-year olds, a measure of the functional and psychosocial impact of oral disorders. Information on the number and pattern of missing teeth for each child were obtained from charts and radiographs. RESULTS: Thirty-six children were included in the study. The number of missing teeth ranged from one to 14 (mean = 6.8). Just over three-quarters of the subjects reported experiencing one or more functional and psychosocial impacts 'Often' or 'Everyday/almost everyday'. Correlations between scale and sub-scale scores and the number of missing teeth were weak and nonsignificant. CONCLUSIONS: Children with oligodontia experience substantial functional and psychosocial impacts from the condition. When compared with other clinical groups, children with oligodontia appear to have worse oral health-related quality of life than children with dental decay and malocclusion, but better oral health-related quality of life than children with oro-facial conditions.

Force characteristics of nickel-titanium open-coil springs.

INTRODUCTION: The objective of this study was to quantify the properties of commercially available nickel-titanium open-coil springs. METHODS: Eleven springs from 3 manufacturers were tested 5 times over a 12-week period. A universal testing machine was used to measure the force generated when open-coil springs were compressed to half of their original length and then gradually allowed to decompress. RESULTS: The average forces generated at the initial recording session for uniformly wound springs from GAC International (Bohemia, NY) and 3M Unitek (Monrovia, Calif) were 19.3% to 42.7% and 9.7% to 38.8% below the manufacturers' labeled force levels, respectively. GAC's 100-, 150-, and 200-g stop-wound coils demonstrated statistically and clinically significant stepwise force degradation over the 12-week experimental period (P <0.0001). GAC's uniformly wound light (100 g) coils generated the lowest load-deflection ratios (23.7 g/mm). CONCLUSIONS: Open coils might need to be compressed by more than one-third of their original length to produce the labeled forces. Uniformly wound coils generally produce lower load-deflection ratios and maximum forces, which are generally more acceptable for tooth movement.

Craniofacial morphology and adolescent facial growth in Pierre Robin sequence.

INTRODUCTION: The purpose of this research was to analyze craniofacial morphology and adolescent facial growth in subjects with Pierre Robin sequence (PRS). The research was conducted at the Center for Craniofacial Care and Research at The Hospital for Sick Children, Toronto, Ontario, Canada, and the Burlington Facial Growth Research Center, Faculty of Dentistry, University of Toronto. METHODS: Longitudinal lateral cephalometric tracings of 34 Caucasian subjects with nonsyndromic PRS were compared with those of unaffected control subjects, matched for age, sex, and ethnicity, and representing the range of occlusions in an untreated population. Cephalometric measurements were obtained before orthodontic treatment (age, 11.8 years) and after orthodontic treatment but before any surgical treatment (age, 16.6 years). Between-group differences of craniofacial measurements were analyzed with paired t-tests, and longitudinal growth differences were analyzed with analysis of variance (ANOVA) adjusted for the growth interval. RESULTS: Significant differences were noted, with the PRS group showing smaller cranial base length, shorter maxillary and mandibular lengths, increased palatal and mandibular plane inclinations, and more open mandibular flexure. Mandibular body length and height were smaller as were ramal length and width, anterior basal thickness, and chin thickness. The ramus-to-body ratio was greater. With growth, greater gains in anterior face and symphyseal height were seen, but the mandible showed less closure of its internal flexure. The maxilla and the mandible remained retrusive during adolescent growth, and the maxilla became more retrognathic. Mandibular morphologic differences persisted in spite of additionally adjusting for cranial base length in the analysis. CONCLUSIONS: Subjects with PRS had reduced cranial base and maxillary and mandibular lengths. Mandibular deficiency was most pronounced in the body. Due to bimaxillary retrognathism, the maxillomandibular dysplasia was not significant. A vertical growth pattern worsened the profile. There was no evidence of adolescent mandibular catch-up growth.

Evaluation of computer-aided learning in orthodontics.

INTRODUCTION: Studies of computer-aided learning (CAL) in orthodontics have documented both objective and subjective outcomes; however, to date, no studies have attempted to correlate these 2 outcome measures. METHODS: The main objective outcome measured was performance on a written test covering material in the orthodontic diagnosis electronic tutorial (ODET) administered to 92 fourth-year undergraduate dental students. The main subjective outcome measured was a 12-statement questionnaire to elicit students' perception of the ODET and CAL as teaching modalities. RESULTS: In the male and female subgroups, a statistically significant difference in mean lecture test scores favoring women (72.46%) over men (67.08%) was observed (P = 0.05). This difference was not observed for mean ODET test scores (P = 0.52). Although responses to the questionnaire were mostly positive, the students are not prepared to replace lectures with CAL tutorials. Responses showed that male students preferred self-instruction as a mode of learning more than female students did (P = 0.05). When linking objective and subjective outcomes, the mean ODET test score had a statistically significant (P = 0.025), but weak, positive correlation (r = 0.243) with self-reported time spent reviewing the ODET but not with any other statement in the questionnaire. CONCLUSIONS: Despite a difference in lecture test scores between male and female students, there was no difference in mean ODET test scores between the 2 subgroups. This might be explained by sex differences: male students preferred self-instruction more than female students did. Improved performance on the ODET test was noted for students who reported longer times spent reviewing the tutorial. Because students are not prepared to replace lectures with CAL tutorials, from their perspective, the ODET should continue to be used with traditional modes of learning.