Radiographic evaluation of enamel thickness of permanent teeth: relevance and applicability.

OBJECTIVE: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. MATERIAL AND METHODS: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. RESULTS: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. CONCLUSION: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.

Artificial intelligence as a prediction tool for orthognathic surgery assessment.

INTRODUCTION: An ideal orthodontic treatment involves qualitative and quantitative measurements of dental and skeletal components to evaluate patients' discrepancies, such as facial, occlusal, and functional characteristics. Deciding between orthodontics and orthognathic surgery remains challenging, especially in borderline patients. Advances in technology are aiding clinical decisions in orthodontics. The increasing availability of data and the era of big data enable the use of artificial intelligence to guide clinicians' diagnoses. This study aims to test the capacity of different machine learning (ML) models to predict whether orthognathic surgery or orthodontics treatment is required, using soft and hard tissue cephalometric values. METHODS: A total of 920 lateral radiographs from patients previously treated with either conventional orthodontics or in combination with orthognathic surgery were used, comprising n = 558 Class II and n = 362 Class III patients, respectively. Thirty-two measures were obtained from each cephalogram at the initial appointment. The subjects were randomly divided into training (n = 552), validation (n = 183), and test (n = 185) datasets, both as an entire sample and divided into Class II and Class III sub-groups. The extracted data were evaluated using 10 machine learning models and by a four-expert panel consisting of orthodontists (n = 2) and surgeons (n = 2). RESULTS: The combined prediction of 10 models showed top-ranked performance in the testing dataset for accuracy, F1-score, and AUC (entire sample: 0.707, 0.706, 0.791; Class II: 0.759, 0.758, 0.824; Class III: 0.822, 0.807, 0.89). CONCLUSIONS: The proposed combined 10 ML approach model accurately predicted the need for orthognathic surgery, showing better performance in Class III patients.

Comparisons of soft tissue changes after Herbst appliance treatment in three different growth phases.

BACKGROUND: This study aimed to compare the soft tissue effects of Herbst appliance in Class II malocclusion patients treated in three different craniofacial growth phases: prepubertal (PRE), circumpubertal (CIR), and postpubertal (POS). METHODS: In total, 95 patients with Class II Division 1 malocclusion previously treated with a Herbst appliance were analyzed. Through the cervical vertebral maturation stages method, patients were allocated into three groups depending on the growth craniofacial phase at the beginning of treatment: PRE, CIR, and POS. Seventeen cephalometric measures were evaluated from each lateral radiograph before and after Herbst therapy using the Radiocef 2 software (Radio Memory, Belo Horizonte). Intragroup and intergroup treatment changes were compared statistically using a paired t test and MANOVA test, respectively. RESULTS: Soft tissue thickness changes were related only to mandible; all three mandibular measurements (L1_LL, B_B', and Pog_Pog') showed thickening for the PRE group ranging from 0.92 mm (Pog_Pog') to 2.02 mm (B_B'), and only lower lip thickened overtime for the POS group (L1_LL = 0.99 mm). Soft and hard tissue pogonion displaced anteriorly, but only the soft tissue showed differences among groups; PRE group presented more anterior displacement than POS group (3.61 mm and 1.39 mm, respectively). Hard and soft tissue facial convexity decreased more in the PRE and CIR groups than in the POS group. Mentolabial sulcus depth reduced more in the PRE (1.07 mm) and CIR (1.29 mm) groups than in the POS (0.55 mm) group. Horizontal movement of the skeletal and soft pogonion presented a moderate-high positive correlation (r = 0.783), and hard and soft facial convexity showed a moderate-low positive correlation (r = 0.403). CONCLUSIONS: Herbst appliance therapy produces soft tissue improvements in the three phases of craniofacial growth, being greater in patients in the PRE and CIR phases.

Radiographic evaluation of enamel thickness of permanent teeth: relevance and applicability

ABSTRACT Objective: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. Material and Methods: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. Results: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. Conclusion: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.

RESUMO Objetivo: Este estudo observacional descritivo teve como objetivo determinar dados clinicamente relevantes e aplicáveis da espessura do esmalte (EES), considerando as diferenças mésiodistais dos dentes anteriores e posteriores e suas relações. Material e Métodos: A amostra consistiu em radiografias periapicais padronizadas do lado direito de 34 indivíduos, 21 do sexo feminino e 13 do sexo masculino, com idade entre 13 e 24 anos (média = 16 anos), com todos os dentes permanentes íntegros e sem apinhamento. Quatro radiografias periapicais e quatro radiografias interproximais foram tiradas e digitalizadas. As medidas de EES (dos pontos de contato mesial e distal até a junção dentina-esmalte) foram realizadas após correção para adequar a ampliação da imagem radiográfica. Para as diferenças entre as médias pareadas, foi aplicado o teste t de Student com correlação de Pearson, para avaliar a correlação entre elas. Resultados: A EES mesial e distal aumenta dos dentes anteriores para os posteriores. A EES dos incisivos variou entre 0,6 e 0,84 mm. Caninos, pré-molares e molares apresentaram EES superior a 1,0 mm e a EES dos molares atingiu valores entre 1,26 e 1,44 mm. Conclusão: As EES distais são significativamente maiores que as mesiais e progressivamente mais espessas dos dentes anteriores para posteriores. A redução interproximal do esmalte (RIP) dos incisivos centrais inferiores e laterais superiores deve ser evitada, minimizada ou realizada em suas superfícies distais. Radiografias periapicais e avaliação da EES remanescente são necessárias nos casos de retratamento. A localização e o número de discrepâncias no tamanho dos dentes devem ser determinados e considerados no planejamento do tratamento, para que sejam adequadamente compensados durante o tratamento com RIP.

Three-Dimensional Evaluation of Dental Arches in Individuals with Syndromic Craniosynostosis.

Objective: Individuals with syndromic craniosynostosis present alterations in the dental arches due to anomalies caused by the early fusion of the craniomaxillary sutures. This study aimed to compare intradental and interdental dimensions between individuals with Apert and Crouzon syndromes and nonsyndromic controls. Materials and Methods: Digital models were obtained from the archive of a public tertiary care hospital. The sample consisted of 34 patients (Apert n = 18, Crouzon n = 16) and 34 nonsyndromic controls matched for gender and age. Measurements of perimeter, length, intercanine and intermolar distances (upper and lower), overjet, and molar ratio were performed. Statistical comparisons were performed using ANOVA and Tukey tests (p < 0.05). Results: Patients with Apert and Crouzon syndromes have severely reduced maxillary transverse dimensions, perimeter, and length of the upper arch compared to the control group (p < 0.001). The lower arch is less impacted. Patients with Apert syndrome had an anterior crossbite (p < 0.001), while patients with Crouzon syndrome had an edge-to-edge bite (p < 0.011). Patients with Apert and Crouzon syndromes do not have serious transverse proportion problems when comparing the upper and lower arches. Conclusions: In this sample, both the Apert and Crouzon groups have severely compromised upper arches compared to the control group. Mild dentoalveolar expansion in the maxilla should be sufficient for the transverse adaptation of the dental arches before frontofacial advancement.

O impacto dos defeitos de esmalte no planejamento ortodôntico / The impact of enamel defects on orthodontic planning

Resumo A decisão pela extração de dentes permanentes para a solução de problemas ortodônticos considera, além da extração em si, outros fatores, dentre eles, as características clínicas do esmalte dos dentes a serem extraídos. O objetivo deste artigo foi apresentar como a presença de defeitos de esmalte dentário (DDE) influenciou na tomada de decisão e modificou o plano de tratamento ortodôntico proposto para o paciente. A severidade do defeito, o número de dentes afetados e a presença e complexidade de má oclusão são fatores que influenciaram na definição do plano de tratamento. Quanto mais grave os defeitos e mais complexa a má oclusão, maior a dificuldade no planejamento do tratamento e, em muitos casos, é indicado incorporar a contribuição de vários especialistas na tomada de decisões. Foi possível demonstrar que o tratamento da má oclusão associada a DDE com a exodontia dos dentes mais severamente afetados apresentou resultados estético e funcional adequados. Concluiu-se que um tratamento bem-sucedido da má oclusão com resultado estético dentofacial adequado, saudável e funcional, requer a compreensão da inter-relação entre os componentes estruturais bucais, oclusão dentária e estética facial.(AU)

Abstract The decision to extract permanent teeth to solve orthodontic problems considers, in addition to the extraction itself, other factors, and among them are the clinical characteristics of the enamel of the teeth to be extracted. The objective of this article was to present how the presence of dental enamel defects (DED) influenced decision-making and modified the proposed orthodontic treatment plan for the patient. The severity of the defect, the number of affected teeth and the presence and complexity of the malocclusion are factors that influenced the definition of the treatment plan. The more severe the defects and the more complex the malocclusion, the greater the difficulty in planning the treatment and, in many cases, it is indicated to incorporate the contribution of several specialists in the decision-making process. It was possible to demonstrate that the treatment of malocclusion associated with DED with the extraction of the most severely affected teeth, presented adequate aesthetic and functional results. It is concluded that a successful treatment of malocclusion with adequate, healthy, and functional dentofacial aesthetic results, requires understanding the interrelationship between oral structural components, dental occlusion and facial aesthetics. (AU)

Would midpalatal suture characteristics help to predict the success rate of miniscrew-assisted rapid palatal expansion?

INTRODUCTION: The objective of this study was to evaluate whether the success or failure of miniscrew-assisted rapid palatal expansion (MARPE) in patients with advanced bone maturation could be related to factors such as midpalatal suture density (MPSD), midpalatal maturation stage (MPSM), midpalatal bone thickness (MBTh), palatal length (PL), expander screw position (ESP), and patient's age. METHODS: Cone-beam computed tomography scans of 25 patients of both sexes, aged 15-37 years (23 ± 7.2), presenting transverse maxillary deficiency and complete skeletal maturation (cervical vertebral maturation stage 5) treated using MARPE were evaluated. The success of MARPE was confirmed by the midpalatal suture opening and failure when no opening or limited separation of midpalatal suture occurred. Data were analyzed using t test for independent samples for differences in the variables of success and failure cases and the Pearson correlation test to evaluate the relation of the success and age, ESP, MPSD, MPSM, PL, and MBTh. RESULTS: Age, MPSM, and MBTh at 12 mm and 16 mm presented statistically significant results (P <0.05). The older the patient with advanced bone maturation, the lower the success rates of MARPE (94.1%, 90%, and 76% for 25, 30, and 37 years, respectively). The ESP had similar averages in cases of success (15.34 mm) and failure (13.51 mm). There was no correlation between ESP, MPSD, MPSM, or PL and MARPE success. CONCLUSIONS: MARPE success was related to age and a greater MBTh at 12 mm and 16 mm.

Microimplant assisted rapid palatal expansion vs surgically assisted rapid palatal expansion for maxillary transverse discrepancy treatment.

INTRODUCTION: This study compared the skeletal and dental changes of microimplant assisted rapid palatal expansion (MARPE) with those produced by surgically assisted rapid maxillary expansion (SARPE) in postpeak adolescents and adults. METHODS: The sample comprised 17 patients (mean age, 26 ± 11 years) selected for the MARPE group and 15 (mean age, 28.5 ± 10.5 years) selected for the SARPE group. Cone-beam computed tomography scans taken just before and after the expansion were used to assess dental and skeletal changes and compare the changes between the groups. RESULTS: MARPE showed greater transversal skeletal changes in the midface and posterior and anterior maxillary base measurements. The transverse displacement of the alveolar process was greater but not significant for the SARPE group than the MARPE group. Regarding dental effects, the root distance measurements did not differ between the groups, but SARPE produced a significantly greater increase in intermolar and interpremolar distance and a greater buccal inclination of the alveolar process and supporting teeth than MARPE. CONCLUSIONS: The MARPE technique showed an increase in skeletal transverse maxillary expansion at the midface and basal bone compared with SARPE, especially at the posterior palatal region; however, no difference was found in the expansion of the alveolar process between the 2 methods. MARPE presented a more parallel expansion in both a coronal and axial view, whereas SARPE led to a V-shaped opening. The greater buccal inclination of the alveolar process and supporting teeth was observed in the SARPE group.

Evaluation of factors related to the success of miniscrew-assisted rapid palatal expansion.

OBJECTIVES: To evaluate whether the success of miniscrew-assisted rapid palatal expansion (MARPE), performed in patients with advanced bone maturation is related to factors such as midpalatal suture (MPS) maturation, age, sex, or bicortical mini-implant anchorage. MATERIALS AND METHODS: Twenty-eight cone beam computed tomography (CBCT) scans of adults and post-pubertal adolescents treated by MARPE were included in the sample. CBCT images before (T0) and after expansion (T1) were used to evaluate the skeletal changes and the success or failure of MARPE. Axial images of MPS were extracted from T0 and classified into one of the five maturation stages. The correlation between MARPE success and the factors of age, sex, MPS maturation, and bicortical mini-implant anchorage was investigated. RESULTS: Only the age showed a statistically significant negative correlation with MARPE success and all the skeletal measures. There was an 83.3% success rate among individuals aged 15 to 19 years, 81.8% from 20 to 29 years, and 20% from 30 to 37 years. MPS maturation showed a negative correlation with the expansion effect. Subjects with stages B or C of MPS maturation showed a 100% success rate, followed by stage D (62.5%) and stage E (58.3%). CONCLUSIONS: As age increased, there was a decrease in MARPE success and the skeletal effects of maxillary expansion. Sex and bicortical mini-implant anchorage were not shown to be relevant factors. There was no correlation between MPS maturation and MARPE success; however, it was observed that all cases of MARPE failure were classified as stage D or E of MPS maturation.

Concomitant permanent maxillary canine agenesis and transposition treated with extractions and lingual brackets.

This case report describes the successful orthodontic treatment for a healthy woman with maxillary canine-premolar transposition associated with rare hypodontia of the contralateral canine. The treatment included extraction of the transposed maxillary right and deciduous maxillary left canines and 2 mandibular second premolars. The objectives of the treatment were to (1) correct the upper midline deviation and the occlusal plane cant, (2) move the maxillary first premolars into the canine position, (3) retract the mandibular incisors to improve the facial profile, and (4) reduce the labial protrusion. Orthodontic treatment was carried out with the lingual technique in the maxillary arch and esthetic ceramic brackets in the mandibular arch. The segmented mechanics were effective, fast, and consistently promoted the necessary movement without side effects. The smile line was improved, resulting in an ideal and esthetic gingival exposition, with the borders of the maxillary teeth following the lower lip smile curvature. The patient achieved ideal dentofacial esthetics, achieved better dental and functional occlusion, was pleased with her improved facial contour, and as a result, showed an improved self-image.

Development and psychometric properties of the Portuguese version of the Orofacial Esthetic Scale: OES-Pt.

BACKGROUND: The Orofacial Esthetic Scale (OES) is an instrument to assess an individual's perception of their Orofacial Appearance (OA). However, its translation and evaluation of psychometric properties is necessary for its use in Brazilian individuals. OBJECTIVES: To develop the Portuguese version of OES (OES-Pt), estimate its psychometric properties (validity, measurement invariance and reliability) when applied to Brazilian individuals aged 18-40 years, and estimate the relationship between sociodemographic characteristics and OA. METHODS: This was a cross-sectional study using a convenience sample. The sample consisted of 1,072 Brazilian individuals (70.1% female, 25.1% dental patients; mean ± SD age: 25.7 ± 5.7 years). After cross-cultural adaptation of OES-Pt, factorial validity was evaluated by confirmatory factor analysis. Convergent validity (average variance extracted (AVE)) and reliability (Cronbach's alpha coefficient (α) and Composite Reliability (CR)) were also estimated. Concurrent validity was assessed (Pearson's correlational analysis (r) between OES-Pt total score and item eight of the OES which refers to global assessment of OA). Measurement invariance of the factorial model (multigroup analysis using ΔCFI) was evaluated for independent samples (sample randomly split into two: "Test Sample" and "Validation Sample" and according to sex: male and female, age range: 18-30 and 31-40 years, and whether the individual is undergoing dental treatment or not). A Structural Equation Model estimated the relationship between sociodemographic characteristics and OA. RESULTS: OES-Pt presented adequate fit to the sample. Convergent validity (AVE ≥ 0.56) and reliability (α and CR ≥ 0.89) were adequate. Concurrent validity was adequate (r = 0.88; p-value < 0.001). OES-Pt presented strict invariance for independent samples. Age, sex, and socioeconomic status (SES) were related to OA, indicated by standardized beta coefficients (standardized ß) of 0.036 (standard error: 0.007), 0.001 (0.094) and 0.196 (0.061), respectively on OA. These three relationships were either weak or not statistically significant. CONCLUSIONS: When measuring OA in Brazilian individuals, the OES-Pt was valid, reliable and invariant for independent samples. Age, sex and SES were weak or not statistically significantly related to OA.

Which one closes extraction spaces faster: en masse retraction or two-step retraction? A randomized prospective clinical trial.

OBJECTIVES: To compare the time to close extraction spaces between en masse (ER) and two-step retraction (TSR). MATERIALS AND METHODS: Forty-eight patients with bimaxillary protrusion underwent treatment with extraction of four first premolars. All patients were randomly allocated to one of two groups: ER (n = 24) or TSR (n = 24). The main outcome was the time required to close spaces between ER and TSR; the closing time of spaces between females and males was a secondary outcome. The size of premolars was measured on the models and data were collected on clinical records at the following times: retraction start date (T1) and space closure completion date (T2). The total time to close the extraction spaces was calculated for each extracted premolar (T1 to T2). The Kaplan Meier method and the Log-Rank test were used to compare the groups. RESULTS: The time to close extraction spaces showed significant differences between the ER and TSR groups. While ER took between 12.1 and 13.8 months, TSR took between 24.7 and 26.8 months. The TSR group showed a significant difference between sexes; male patients took 5.5 months longer than female patients for the extraction spaces to close. CONCLUSIONS: TSR takes between 1.8 and 2.2 times longer than ER to close the extraction spaces and it took longer in males than females.

Pain perception in orthodontic patients: A model considering psychosocial and behavioural aspects.

OBJECTIVES: To estimate the agreement between orthodontic pain perception, evaluated with the visual analog scale (VAS), and psychosocial and behavioural aspects of pain and to estimate the impact of clinical and demographic characteristics on these aspects. DESIGN: Cross-sectional design using non-probabilistic sampling. SETTING AND SAMPLE POPULATION: Orthodontic patients undergoing treatment at orthodontic clinics (n = 507 [63.3% women], mean age: 26.32 [SD = 11.70] years). MATERIALS AND METHODS: Psychosocial and behavioural aspects of pain were evaluated using the Multidimensional Pain Inventory (MPI-Orthodontic). Agreement between the pain impact level assessed according to different methods was estimated using the linear-weighted Kappa (κp ) statistic. Structural models were elaborated to estimate the impact of clinical and demographic characteristics on the psychosocial and behavioural aspects of pain. The fit of the model was evaluated, and the z test (α = 5%) was used to estimate the significance of the impact (ß). RESULTS: The agreement between VAS and MPI-Orthodontic factors was inadequate (κp  = 0.028-0.584). The fit of the structural models was adequate. Women, younger individuals, and those who reported difficulty/pain with feeding exhibited greater perception of both the psychosocial and behavioural aspects. Individuals in lower socioeconomic strata who were not satisfied with treatment and did not seek treatment voluntarily exhibited greater perception of the psychosocial aspect of pain. CONCLUSIONS: The impact of orthodontic pain on psychosocial and behavioural aspects of patients' lives is a relevant issue. Clinical and demographic characteristics contributed to these aspects; however, pain intensity as a sole measure may be insufficient for an adequate understanding of pain perception.

Low-level laser therapy (830 nm) on orthodontic pain: blinded randomized clinical trial.

The objective of this research was to compare the effect single low-level laser therapy (LLLT) irradiation on pain perception in patients having fixed appliance treatment in the clinic of orthodontics. Sixty-two patients were recruited to participate in this randomized, double-blinded, placebo-controlled study. The patients were assigned to four groups: group I-laser on the right side; group II-placebo on the right side; group III-laser on the left side; group IV-placebo on the left. The laser or placebo was applied before separation, 24 and 48 h after separation of their first permanent molars in the lower arch. Just after the separation, the average of the pain for the placebo group was 1.6, significantly greater than the average of 1.1 registered for the laser group (p = 0.013). After 24 h and before the new irradiation, the values registered among the different groups did not show any differences. In relation to the gender, only after the first irradiation in placebo group, the female had a level of pain (0.1) significantly higher (p = 0.04) compared to male, and after 48 h, the group where the laser was applied had a difference (p = 0.04) among the gender with a value of lower pain for men (0.6) than for women (1.6).The laser irradiation to minimize the pain was only effective when applied immediately after treatment and separation. In general way, there were no differences between the genders, except after the first placebo group irradiation in which the female had a significantly higher level of pain compared to male and after 48 h. The pain cycle observed in this study had its peak in 24 h, both for laser's and placebo's group.

Enamel Roughness Changes after Removal of Orthodontic Adhesive.

The aim of this study was to evaluate enamel roughness, quality of the enamel surfaces and time duration comparing different orthodontic adhesive removal protocols. Premolars were used to test three adhesive removal methods (n = 20): five-blade carbide bur, 30-blade carbide bur, and ultrasonic diamond bur. Bracket was bonded using TransbondTM XT adhesive. Roughness with different parameters was measured before bracket bonding and after adhesive remnants removal. Micromorphological analysis of enamel surface (n = 5) was performed by SEM images and categorized in enamel damage index-"perfect"; "satisfying"; "imperfect"; and "unacceptable". Time was measured in seconds. All removal methods caused increased roughness in relation to Ra, Rq, and Rz parameters (X axis) comparing to healthy enamel surface. Enamel surface resulted from removal using five-blade burs was scored as satisfactory. Carbide bur groups decreased the roughness values of Ra, Rq, and Rz parameters on the Y axis and enamel surface was considered unacceptable. The 30-blade group increased symmetry (Rsk) and flattening (Rku) parameters of roughness and surface was scored as unsatisfactory. Diamond bur removed adhesive in 54.8 s, faster than five-blade carbide bur. The five-blade bur group resulted in less enamel roughness than the 30-blade and diamond groups.

Dental skeletal effects of the metallic splinted Herbst appliance after growth spurt: a lateral oblique cephalometric assessment.

The aim of this study was to evaluate dental and skeletal changes induced by the use of Herbst appliance compared to natural growth in young adults with Class II division I malocclusion with mandibular retrusion, by means of lateral oblique radiographs. Forty-six subjects, I4 -18 years old, after pubertal growth peak, with Class II division I malocclusion were assessed. Subjects were divided into two groups: the Experimental group included 23 subjects treated with Metallic Splinted Herbst and the Control group included 23 subjects followed without treatment. The Experimental and Control groups were paired by sex and chronological age. Oblique lateral cephalometric radiographs of the left and the right side of the mandible before treatment (TI) and after 8 months' treatment (T2) were used to evaluate dental and skeletal changes. Statistical analysis was performed with Intra Class Correlation and Student t-test, according to the study hypothesis. The results showed that the appliance corrected the Class II relationship in an 8-month period by mesial tipping movement of lower permanent first molars. It had little influence on mandibular structure and mandibular length and no influence on maxillary structure and upper molar. To conclude, late treatment of Class II malocclusion with the Herbst appliance was accomplished by means of dentoalveolar changes. These findings suggest that this type of treatment can be used in patients after growth has ceased because the results do not depend upon skeletal changes.

O objetivo é avaliar mudanzas dento esqueléticas induzidas pelo uso do aparelho de Herbst considerando crescimento natural através da telerradiografía cefalométrica em 45o em adultos jovens com Classe II divisao 1 e retrusao mandibular. Uma amostra de 46 individuos com idade entre 14 a 18 anos, após surto de crescimentopubertário, Classe II divisao 1 foram avaliados e divididos em dois grupos: grupo Experimental, 23 individuos que foram tratados com Herbst splint metálico e grupo Controle, 23 individuos que foram acompanhados sem tratamento. Os grupos experimental e Controle foram pareados por genero e idade cronológica. Foram usadas telerradiografias cefalométrica em 45o dos lados esquerdo e direito da mandíbula antes do tratamento (T1) e após periodo de 8 meses de tratamento e seguinte (T2) para avaliar as mudanzas dento esqueléticas. Análise estatistica foi realizada com o indice de Correlagao Intra Classe e teste t de Student de acordo com a hipótese do estudo. Os resultados mostraram que houve corregaoda relagao de Classe II no periodo de 8 meses por movimento mesial do primeiro molar inferior. O aparelho teve pequena influencia na estrutura mandibular e compri-mento mandibular e nenhuma influencia na estrutura maxilar e molar superior. Em conclusao, o tratamento tardio da má-oclusao de Classe II com o aparelho MESPHER foi alcangado através de mudangas dento alveolares.

Influence of the cranial base flexion on Class I, II and III malocclusions: a systematic review.

OBJECTIVE: The aim of this study was to perform a systematic review on the morphological characteristics of the skull base (flexion, anterior length and posterior length) and the concomitant development of malocclusions, by comparing differences in dimorphism, ethnicity and age. METHODS: The articles were selected by means of electronic search on BBO, MEDLINE and LILACS databases from 1966 to 2016. A qualitative evaluation of the methodologies used on the articles was also performed. RESULTS: Although the literature on this topic is abundant, only 16 articles were selected for the present systematic review. The cranial base angle itself does not seem to play a significant role in the development of malocclusions. In fact, the cranial base angle is relatively stable at the ages of 5 to 15 years. CONCLUSIONS: A more obtuse angle at the skull base, in association or not with a greater anterior length of the cranial base, can contribute to the development of Class II division 1 malocclusions. On the other hand, a more acute angle at the skull base can contribute to a more anterior positioning of the mandible and to the development of Class III malocclusions.

Influence of the cranial base flexion on Class I, II and III malocclusions: a systematic review

ABSTRACT Objective: The aim of this study was to perform a systematic review on the morphological characteristics of the skull base (flexion, anterior length and posterior length) and the concomitant development of malocclusions, by comparing differences in dimorphism, ethnicity and age. Methods: The articles were selected by means of electronic search on BBO, MEDLINE and LILACS databases from 1966 to 2016. A qualitative evaluation of the methodologies used on the articles was also performed. Results: Although the literature on this topic is abundant, only 16 articles were selected for the present systematic review. The cranial base angle itself does not seem to play a significant role in the development of malocclusions. In fact, the cranial base angle is relatively stable at the ages of 5 to 15 years. Conclusions: A more obtuse angle at the skull base, in association or not with a greater anterior length of the cranial base, can contribute to the development of Class II division 1 malocclusions. On the other hand, a more acute angle at the skull base can contribute to a more anterior positioning of the mandible and to the development of Class III malocclusions.

RESUMO Objetivo: o objetivo desse estudo foi realizar uma revisão sistemática sobre as características morfológicas da base do crânio (flexão, comprimento anterior e comprimento posterior) e o desenvolvimento concomitante da má oclusão, comparando as diferenças do dimorfismo, etnia e idade. Métodos: os artigos foram selecionados por meio de busca eletrônica nas bases de dados BBO, MEDLINE e LILACS, de 1966 a 2016. Uma avaliação qualitativa da metodologia dos artigos também foi executada. Resultados: ainda que a literatura seja abundante nesse assunto, somente 16 artigos foram selecionados para a presente revisão sistemática. O ângulo da base do crânio, por si só, não parece desempenhar papel significativo no desenvolvimento das más oclusões. De fato, o ângulo da base do crânio é relativamente estável dos 5 aos 15 anos. Conclusões: um ângulo mais obtuso na base do crânio, associado ou não a um comprimento maior, pode contribuir para o desenvolvimento da má oclusão de Classe II, divisão 1. Por outro lado, um ângulo mais agudo na base do crânio pode contribuir para um posicionamento mais anterior da mandíbula e para o desenvolvimento da má oclusão de Classe III.

Effects of surgically assisted rapid maxillary expansion on mandibular position: a three-dimensional study.

BACKGROUND: This study aimed to evaluate three-dimensional changes in mandibular position after surgically assisted rapid maxillary expansion (SARME). METHODS: A retrospective study was carried out with tomographic records of 30 adult patients with maxillary transverse deficiency who underwent SARME. Cone beam computed tomography scans were obtained preoperatively (T1), after expansion (T2) and 6 months after expansion (T3). Mandibular landmarks were measured with respect to axial, sagittal, and coronal planes. Repeated measures ANOVA was used for statistical analysis. RESULTS: Clockwise rotation and lateral displacement of the mandible were observed immediately after SARME. However, mandibular displacements tended to return close to their initial values at T3. CONCLUSIONS: Clockwise rotation and lateral shift of the mandible are transient effects of SARME.

Manejo ortodôntico da agenesia de incisivo inferior / Orthodontic management of lower incisor agenesis

O sucesso do tratamento de pacientes com agenesia de incisivo inferior depende dos fatores dentários, esqueléticos e faciais associados. No planejamento considerações estéticas e funcionais são importantes para a escolha da forma de tratamento mais apropriado, quer seja a adequação da oclusão dentária ou a reabilitação protética do espaço deixado pela ausência. Esse artigo tem como objetivo descrever duas formas de abordagem para correção dos vários aspectos decorrentes da agenesia de um incisivo inferior. Pode-se concluir que a agenesia de incisivos inferiores pode comprometer a oclusão dentária, o desenvolvimento alveolar anterior inferior, a região de sínfise mandibular, a estética facial e o equilíbrio funcional lábio-lingual. O diagnóstico precoce e planejamento adequado do tratamento envolvendo equipe multidisciplinar podem produzir resultados favoráveis, evitando o impacto negativo da ausência congênita na qualidade de vida da criança pela redução dos sintomas bucais e limitação funcional, promovendo seu bem-estar emocional e social.( AU)

Treatment success of patients with lower incisor agenesis depends on associated dental, skeletal and facial factors. When planning, aesthetic and functional considerations are important for choosing the most appropriate form of treatment, whether it is the adequacy of dental occlusion or the prosthetic rehabilitation of the space left by the absence. This article aims to describe two approaches to correct the various aspects resulting from the lower incisor agenesis. We can conclude that agenesis of lower incisors may compromise dental occlusion, lower anterior alveolar development, mandibular symphysis region, facial aesthetics and lip-tongue functional balance. Early diagnosis and adequate treatment planning involving a multidisciplinary team can produce favorable results, avoiding the negative impact of congenital absence on the child's quality of life through reduction of oral symptoms and functional limitation, promoting his/her emotional and social well-being.. (AU)