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.

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.

Ectopic Eruption of the Permanent Maxillary First Molar: Predictive Factors for Irreversible Outcome.

PURPOSE: The purpose of this study was to determine the rate of self-correction and predictive factors for irreversible outcome of mesial ectopic eruption of permanent maxillary first molars (EE), in a sample population where no interceptive treatment was initiated. METHODS: Charts of patients diagnosed with EE were reviewed, and radiographs were analyzed for predictive factors reported in the literature. RESULTS: Sixty-five EE were included in the study; 46 (71 percent) self-corrected, of which one-third occurred after age nine years. Space loss, with an average of approximately three mm, occurred in 18 EE (28 percent). Increased magnitude of impaction, degree of resorption of the primary second molar, severe lock, and bilateral occurrence were positively correlated with irreversible EE. Multiple regression analysis was positive for increased magnitude of impaction when adjusted for gender and bilateral occurrence. CONCLUSION: Spontaneous self-correction occurred in 71 percent of permanent maxillary first molars with ectopic eruption; one third of self-corrections occurred after nine years of age. Delaying treatment of ectopic eruption of permanent maxillary first molars may be a viable option when the outcome is uncertain. Increased magnitude of impaction was the most reliable predictor associated with irreversible outcome.

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.

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.

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.

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.

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.

Archwire depth is a significant parameter in the frictional resistance of active and interactive, but not passive, self-ligating brackets.

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, CarrièreSLB, ClaritySL, SmartClip, VisionLP). Each bracket was tested on three rectangular stainless steel wires: 0.017 × 0.022 inch, 0.017 × 0.025 inch, and 0.019 × 0.025 inch. A two-way balanced analysis of variance was used for statistical analysis. RESULTS: The four passive self-ligating brackets (CarrièreSLB, 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.

Predictors of adolescent compliance with oral hygiene instructions during two-arch multibracket fixed orthodontic treatment.

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.

Prevalence and patterns of permanent tooth agenesis in Down syndrome and their association with craniofacial morphology.

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.

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.

Cranial base, maxillary and mandibular morphology in Down syndrome.

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.

Efeitos dentoesqueléticos do aparelho extrabucal de tração occipital no tratamento da má-oclusão de classe II, divisão 1 / Dentoskeletal effects of the extraoral occipital traction appliance on the treatment of class II, division 1 malocclusion

O objetivo deste estudo foi comparar as alterações dentoesqueléticas decorrentes do tratamento exclusivo com o aparelho extrabucal de tração occipital em pacientes com más-oclusões de Classe II, Divisão I, com um grupo controle com o mesmo tipo de má-oclusão. O grupo experimental compreendeu 25 pacientes (dez meninos e 15 meninas), com média de idade inicial e final de 10,28 e 1 1,82 anos, respectivamente e período médio de tratamento de 1,54 anos. O grupo controle consistiu de 31 indivíduos (22 meninos e nove meninas), com média de idade inicial e final de 9,08 e 12,11 anos, respectivamente. Utilizaram-se telerradiografias de todos os indivíduos, obtidas antes e após a colocação do aparelho e do período de observação. O test "t" pareado foi utilizado na comparação intragrupos e o test "t" na comparação intergrupos. A tendência de deslocamento anterior da maxila foi alterada,'apresentando melhora na relação maxilomandibular e na convexidade facial. O comportamento vertical maxilar foi equilibrado e o desenvolvimento dos molares superiores no sentido vertical e sagital foi restringido. Concluiu-seque o uso do aparelho extrabucal de tração occipital é eficiente na correção das más-oclusões de Classe II, Divisão I, sendo indicado para pacientes meso e dolicofaciais.

The aim of this prospective study was to compare the dentoskeletal alterations resulting from treatment exclusively with the Extraoral occipital fraction appliance in patients with Class II, Division I, malocclusions with a control group with the same type of malocclusion. The Experimental group comprised 25patients (ten boys and 15 girls), with initial and final mean ages of 10.28 and 11.82 years, respectively and a treatment mean period of 1.54 years. The Control group consisted of 31 individuals (22 boys and 9 girls). with initial and final mean ages of 9.08 and 12.11 years, respectively. Lateral cephalometric radiographs were taken before and after placement of the appliance and of the period of observation. The paired t-test was used in the intragroup comparison and the t-test in the intergroup comparison. The trend towards anterior displacement of the maxilla was altered, presenting improvement in the maxillomandibular relationship and in facial convexity. The vertical maxillary behavior was balanced and development of the maxillary molars in the vertical and sagittal directions was restricted. The use of the Extraoral occipital traction appliance is very efficient for correcting Class 11, Division I, malocclusions, being an excellent option of treatment.

A study of the frictional characteristics of four commercially available self-ligating bracket systems.

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 x 0.022, 0.019 x 0.025, 0.020 round, and 0.021 x 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 fixed 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 significantly (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.

Estudo cefalométrico das alterações dentoesqueléticas da má oclusão de Classe II, divisão 1 tratada com o aparelho de Herbst com cantiléver / Cephalometric study in patients that displayed Class II, division 1 malocclusion treated with herbst appliance

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<0,05) evidenciou que a terapia corrigiu, em curto prazo, a má oclusão inicial, com grandes alterações dentoalveolares, em decorrência da perda substancial de ancoragem dentária, mesializando os molares inferiores e vestibularizando os incisivos inferiores. A terapia restringiu o desenvolvimento normal no sentido vertical dos dentes póstero-superiores, contribuindo decisivamente para a correção da relação molar de Classe II e manutenção do padrão de crescimento craniofacial dos pacientes.

OBJECTIVE: This study investigated the treatment effects on the craniofacial growth of Class II patients treated with Herbst appliance. METHODOLOGY: The sample was comprised of two groups, one experimental and one control group. The experimental group originated from Bauru Dental School, University of São Paulo. This consisted of 25 patients treated by the Herbst appliance, with an initial mean age of 12,01 years. The control group, matched by age with the experimental group, was originated from the Burlington Growth Centre, located at the Faculty of Dentistry, University of Toronto, Canada. All patients were assessed at the beginning (T1) and at the end of the treatment or observation period (T2) and 33 cephalometric variables were established. RESULTS AND CONCLUSIONS: The statistical comparison between the experimental group and the control group (Student t test) showed in short-term fashion, the correction of the initial malocclusion with pronounced dental changes (loss anchorage). The effect in inhibiting the vertical development of the maxillary first molars, essential characteristic to correct the Class II molar relationship and to maintain the craniofacial growth pattern, was shown with the therapy.

Mandibular morphology and growth with and without hypodontia in subjects with Pierre Robin sequence.

INTRODUCTION: Mandibular micrognathia is the hallmark of Pierre Robin sequence (PRS). A high prevalence of mandibular hypodontia has been reported in subjects with PRS. The hypothesis of this study is that the morphology of the mandible in subjects with PRS and mandibular hypodontia is different from that in subjects with PRS but without mandibular hypodontia. METHODS: The study was conducted at the craniofacial center of The Hospital for Sick Children in Toronto. The study sample comprised 16 caucasian children with nonsyndromic PRS (7 boys, 9 girls) with mandibular hypodontia and 18 white children with nonsyndromic PRS (6 boys, 12 girls) without hypodontia. Longitudinal lateral cephalograms were available before orthodontic treatment (T1; mean age, 11.7 years) and after orthodontic treatment but before orthognathic surgery (T2; mean age, 16.6 years). A new, customized cephalometric analysis with additional landmarks and measurements to study mandibular morphology was performed. Differences in measurements were studied by using analysis of variance adjusted for age and sex. RESULTS: Cephalometric measurements were smaller in the group with mandibular hypodontia at T1: mandibular length (3.36 mm, P = .04), ramal length (2.78 mm, P = .04), posterior facial height (3.97 mm, P = .03), and mandibular molar eruption (1.96 mm, P = .02). At T2, the differences increased: mandibular length (4.56 mm, P = .02), ramal length (4.04 mm, P = .002), posterior facial height (5.98 mm, P = .001), and mandibular molar eruption (2.08 mm, P = .04). Comparison of growth increments between the 2 groups from T1 to T2 showed a greater cranial base deflection increment in the group with mandibular hypodontia (0.88 degrees, P = .02) and a larger posterior facial height increment in the group without mandibular hypodontia (2.02 mm, P = .04). CONCLUSIONS: Children with nonsyndromic PRS with mandibular hypodontia had smaller mandibles than children with nonsyndromic PRS and normal complements of mandibular teeth. Their patterns of growth did not improve during adolescence, and the magnitude of differences increased.

Mandibular growth following reconstruction using a free fibula graft in the pediatric facial skeleton.

BACKGROUND: Mandible reconstruction in the growing facial skeleton is challenging, especially with reconstructions necessitating free vascularized bone grafts. The need for further combined orthodontic-orthognathic intervention at skeletal maturity must be anticipated. The growth potential of these grafts and potential new problems associated with performing a sagittal split osteotomy at skeletal maturity are poorly understood. METHODS: A retrospective chart review revealed 11 patients who underwent reconstruction with a free fibula at The Hospital for Sick Children from 1990 to 2000. Radiographic and photographic studies were assessed for long-term growth of the reconstructed mandible, with follow-up ranging from 2 to 12 years. RESULTS: Of the 11 patients who underwent reconstruction with a free fibula, two had surgery at skeletal maturity, two moved out of the country, one died as a result of her malignancy, and one was lost to follow-up. The remaining five patients are being followed by the craniofacial and orthodontic services and have not reached skeletal maturity. Of the two patients who have had orthognathic surgery, the one patient whose reconstruction involved the temporomandibular joint exhibited no growth on the reconstructed side and required a 57-mm advancement on the reconstructed side. The other patient, who had preservation of the temporomandibular joint at the time of reconstruction, required only a 5-mm advancement on the reconstructed side. Both patients had significant surgical complications as a result of the initial reconstructive techniques. Technical modifications necessary at the initial reconstruction became apparent when the authors performed a sagittal split osteotomy on the reconstructed side. CONCLUSIONS: Certain technical modifications to the original free fibula reconstructed pediatric mandible should be considered in anticipation of the need for a subsequent bilateral sagittal split at skeletal maturity.

Predisposing factors to formation of cleft lip and palate: inherited craniofacial skeletal morphology.

OBJECTIVE: To identify inherited craniofacial morphologic features in individuals at high risk for cleft of the lip, cleft palate, or both. SUBJECTS: Twins without cleft from 33 pairs of monozygotic twins discordant for cleft lip, cleft palate, or both were studied. There were 17 males and 16 females of Caucasian origin, ranging from 3 to 18 years (15 with cleft lip and palate [CLP], 10 with cleft lip [CL], and 8 with cleft palate [CP]), collected from five craniofacial centers (United States and Canada). DESIGN: The twin without cleft (noncleft) from each set was compared with an age- and sex-matched control individual from the Burlington Growth Centre, Toronto, Ontario. Posteroanterior and lateral cephalograms were traced and digitized using a computer custom analysis. Descriptive statistics, Student's t tests, and analysis of variance were used to test 40 variables in a pilot study comparing the noncleft twin groups with the controls. Preliminary analysis permitted pooling of the CLP and CL groups (n = 25). To minimize false-positive significance, only 14 variables (from the maxillofacial area) were tested. RESULTS: Using the raw probabilities, eight variables showed significant differences between the pooled noncleft CLP and CL (CL[P]) twin group and the controls. However, when the level of significance was adjusted, only four (nasal width [p < .01], cranial base length [p < .05], cranial base width/length ratio [p < .001], and maxillary width/length ratio [p < .05]) were significantly different. No significant differences were confirmed between the noncleft CP twin group and the controls. CONCLUSIONS: The noncleft member of a discordant monozygotic pair has a number of facial characteristics that differ from the general population. These may predispose to the formation of a cleft lip or palate and may result from a deficiency or distortion of the mesenchyme that forms the craniofacial structures.

Simultaneous functional and fixed appliance therapy for growth modification and dental alignment prior to prosthetic habilitation in hypohidrotic ectodermal dysplasia: a clinical report.

This clinical report describes the simultaneous use of functional and fixed appliances to modify the pattern of dentofacial development and align teeth in preparation for prosthodontic habilitation of a growing child with hypohidrotic ectodermal dysplasia. The treatment objective was to create a more favorable starting point for the prosthodontic phase of habilitation by improving the sagittal and vertical skeletal relationships and facial esthetics. This was accomplished through growth modification with functional appliances conducted simultaneously with eruption of maxillary and mandibular molars, dental arch expansion, alignment, and space management using fixed orthodontic appliances. Orthodontic retention was accomplished by means of removable partial dentures. A second phase of orthodontics conducted closer to the age of skeletal maturation will aim at definitive tooth alignment in preparation for dental implant-supported restorations.