Accuracy of arch expansion with two thermoplastic materials in Invisalign® patients: EX30® and SmartTrack®.

OBJECTIVE: The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane). METHODS: The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test. RESULTS: Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible. CONCLUSIONS: It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.

Accuracy of Invisalign® aligners in adult patients: a retrospective study of angular tooth movements.

OBJECTIVE: This retrospective study aimed to assess the predictability of Invisalign® aligners regarding rotational, mesio-distal and buccal-lingual tip movements. METHODS: Two materials were included in the analysis - EX30, used until 2013; and SmartTrack, in current use. The study comprised 56 adult patients treated with Invisalign Comprehensive. Data sample were assessed on three sets of digital models; model 1 - initial, model 2 - predicted, and model 3 - achieved. Sixty reference points were marked in each dental arch, and two reference planes assisted the superimposition. The degree of rotation, mesio-distal and buccal-lingual tip was obtained via trigonometric calculations, through a previously published validated method. The accuracy of outcomes was compared according to the types of tooth movement and teeth groups,and the influence of predetermined variables on movement accuracy was also investigated. RESULTS: Rotation and mesio-distal tip did not present any significant difference when comparing EX30 and SmartTrack groups. Only buccal-lingual tip presented a significant difference, incisor and canine groups treated with EX30 aligners presented an increase in accuracy (p= 0.007 and p = 0.007, respectively). For each additional degree planned for rotation movements, there was an increase of 0.35° in the discrepancy, and an increase of 0.40° and 0.41° for mesio-distal and buccal-lingual tip, respectively. EX30 and SmartTrack discrepancies were compared by multilevel linear regression. CONCLUSION: EX30 aligners reached higher accuracy for buccal-lingual tip in anterior teeth. However, for rotation and mesio-distal tip, SmartTrack and EX30 are similarly accurate. The total amount of planned movement has a significant impact on accuracy rates, with a decrease in accuracy for every additional degree.

Temporomandibular joint disc position and shape in patients submitted to two protocols of rapid maxillary expansion and face mask therapy: A randomized clinical trial.

OBJECTIVE: The objective of this prospective study was to assess possible changes in the position and shape of the temporomandibular joint (TMJ) articular disc in patients treated with two protocols of rapid maxillary expansion (RME) and face mask (FM) therapy. METHODS: A sample of 88 patients with Class III or Class III subdivision malocclusions, aged between 6 and 13 years, were consecutively selected and divided into three groups (G): G1-34 patients were treated with RME, followed by FM therapy; G2-34 patients were treated using RME according to modified alternate rapid maxillary expansion and constriction (ALT-RAMEC) protocol, followed by FM therapy. These treated groups were randomly (1:1 allocation ratio) distributed according to the two treatment protocols. G3 - Control Group - 20 untreated patients were followed. Magnetic resonance imaging (MRI) TMJs were obtained before (T1) and after (T2) a treatment period or follow-up. McNemar test, Fisher's exact test and intra- and inter-observer concordance (K) were performed (p ≤ .05). RESULTS: There were no statistically significant differences in the baseline cephalometric variables at T1 between the groups. There were statistically significant differences between the groups (p < .001) in relation to the disc shape in T1, since G1 (8 TMJs -11.76%) presented higher occurrences of altered forms in comparison with G2 (no changes). No significant differences were observed in disc position CM and OM (G1 - p > .999; G2 - p = .063; G3 - p = .500) and shape (G1 - p > 0.999; G2 - p = .250; G3 - not calculable), between T1 × T2, in any of the groups studied. CONCLUSION: The two treatment protocols did not have adverse effects on the position and shape of the TMJ disc, in a short-term evaluation.

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.

Accuracy of arch expansion with two thermoplastic materials in Invisalign® patients: EX30® and SmartTrack®

ABSTRACT Objective: The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane). Methods: The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test. Results: Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible. Conclusions: It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.

RESUMO Objetivo: O objetivo deste estudo retrospectivo foi comparar a acurácia na expansão da arcada utilizando alinhadores Invisalign com dois tipos de material termoplástico: EX30® (Polietileno Tereftalato Glicol, ou PETG) e SmartTrack® (poliuretano). Método: A amostra desse estudo incluiu 65 pacientes adultos tratados consecutivamente em dois consultórios particulares: grupo 1 - tratado com EX30® (358 dentes), e grupo 2 - tratado com SmartTrack® (888 dentes). Foram avaliadas 623 medidas em três pares de modelos digitais, ao longo do tratamento: modelo 1 - inicial, modelo 2 - posição dentária planejada, modelo 3 - posição alcançada. Foram marcados 16 pontos de referência por arcada e, após o bestfit, 2 pontos por arcada foram copiados de um modelo digital para o outro. Medidas lineares de ambas as arcadas foram aferidas para caninos, pré-molares e primeiros molares, localizadas na margem gengival lingual e ponta de cúspide de todos os dentes. Foram realizadas comparações usando os testes Wilcoxon e Mann-Whitney. Resultados: Ambos os materiais termoplásticos apresentaram diferenças significativas entre os valores planejados e alcançados em todas as medidas, exceto na ponta de cúspide dos primeiros molares inferiores do grupo SmartTrack®. Não houve diferença estatística entre esses dois materiais quanto à acurácia da expansão transversa. Em termos gerais, a acurácia dos alinhadores EX30® na maxila e mandíbula foi de 37% e 38%, respectivamente. O grupo SmartTrack® apresentou acurácia de 56,62% e 68,72% na maxila e mandíbula, respectivamente. Conclusões: Não foi possível afirmar que um material expande melhor que o outro. Estudos clínicos controlados futuros devem ser conduzidos comparando SmartTrack® e EX30® sob condições similares.

Accuracy of Invisalign® aligners in adult patients: a retrospective study of angular tooth movements

ABSTRACT Objective: This retrospective study aimed to assess the predictability of Invisalign® aligners regarding rotational, mesio-distal and buccal-lingual tip movements. Methods: Two materials were included in the analysis - EX30, used until 2013; and SmartTrack, in current use. The study comprised 56 adult patients treated with Invisalign Comprehensive. Data sample were assessed on three sets of digital models; model 1 - initial, model 2 - predicted, and model 3 - achieved. Sixty reference points were marked in each dental arch, and two reference planes assisted the superimposition. The degree of rotation, mesio-distal and buccal-lingual tip was obtained via trigonometric calculations, through a previously published validated method. The accuracy of outcomes was compared according to the types of tooth movement and teeth groups,and the influence of predetermined variables on movement accuracy was also investigated. Results: Rotation and mesio-distal tip did not present any significant difference when comparing EX30 and SmartTrack groups. Only buccal-lingual tip presented a significant difference, incisor and canine groups treated with EX30 aligners presented an increase in accuracy (p= 0.007 and p = 0.007, respectively). For each additional degree planned for rotation movements, there was an increase of 0.35° in the discrepancy, and an increase of 0.40° and 0.41° for mesio-distal and buccal-lingual tip, respectively. EX30 and SmartTrack discrepancies were compared by multilevel linear regression. Conclusion: EX30 aligners reached higher accuracy for buccal-lingual tip in anterior teeth. However, for rotation and mesio-distal tip, SmartTrack and EX30 are similarly accurate. The total amount of planned movement has a significant impact on accuracy rates, with a decrease in accuracy for every additional degree.

RESUMO Objetivo: Esse estudo retrospectivo teve como objetivo aferir a previsibilidade dos alinhadores Invisalign em relação aos movimentos de rotação e inclinações mesiodistal e vestibulolingual. Material e Métodos: Foram incluídos dois materiais nessa análise: EX30®, utilizado até 2013; e SmartTrack®, atualmente em uso. Esse estudo avaliou 56 pacientes tratados com Invisalign Comprehensive. Os dados foram avaliados em três pares de modelos digitais; modelo 1 - inicial, modelo 2 - planejado, e modelo 3 - alcançado. Foram marcados 60 pontos de referência em cada arcada, sendo a sobreposição realizada com auxílio de planos de referência. O grau de rotação e inclinações mesiodistal e vestibulolingual foi obtido por cálculos de trigonometria, usando um método validado publicado anteriormente. Os resultados foram comparados de acordo com os tipos de movimento dentário e grupos de dentes, também foi investigada a influência de variáveis predeterminadas na confiabilidade dos movimentos. Resultados: Os movimentos de rotação e inclinação mesiodistal não apresentaram diferença estatística, quando comparados os grupos EX30® e SmartTrack®. Somente a inclinação vestibulolingual apresentou diferença estatisticamente significativa, sendo que os grupos de incisivos e caninos tratados com alinhadores EX30® apresentaram um aumento na previsibilidade(p= 0,007 e p= 0,007, respectivamente). Para cada grau adicional planejado para movimento de rotação, ocorreu um aumento de 0,35° na discrepância, e aumentos de 0,40° e 0,41° para as inclinações mesiodistal e vestibulolingual, respectivamente. As discrepâncias entre EX30® e SmartTrack® foram comparadas por regressão linear multinível. Conclusão: Os alinhadores EX30® alcançaram maior previsibilidade para a inclinação vestibulolingual em dentes anteriores. No entanto, para rotação e inclinação mesiodistal, SmartTrack® e EX30® apresentaram previsibilidade similar. A quantidade total de movimento planejado apresenta influência significativa nas taxas de previsibilidade, com diminuição na acurácia para cada grau adicional.

Dental changes induced by a modified Herbst appliance followed by fixed appliances: A digital dental model analysis.

BACKGROUND: Herbst therapy is an effective treatment for Class II malocclusions. However, the maintenance of the effects after fixed appliances treatment remains questionable. This retrospective study aimed to assess, using digital dental models, the sagittal and transverse dental arch changes in young patients during two Class II Division 1 treatment phases, first with modified Herbst appliance (HA) and then with fixed appliances. METHODS: The treated group (TG) comprised 32 patients (17 boys, 15 girls; mean age, 12.85 ± 1.16 years) treated with HA and fixed appliances. The control group comprised 28 patients (13 boys, 15 girls; mean age, 12.21 ± 1.35 years) with untreated Class II malocclusions. Digital models were obtained immediately before and after HA therapy and after fixed appliances. Data were statistically analyzed. RESULTS: Compared with the control group, the TG showed an increase in maxillary and mandibular arch perimeters and in intercanine and intermolar arch widths, a decrease in overjet and overbite, and an improvement in canine and molar relationships. In the time after HA therapy until the end of fixed appliances treatment, the TG showed a decrease in maxillary and mandibular arch perimeters, overjet, upper and lower intermolar widths; an increase in molar Class II relationship; and no changes in canine relationship, overbite, and upper and lower intercanine widths. CONCLUSIONS: In this sample of patients treated with HA, on average, there was an improvement in the Class II relationship, which seemed to remain after fixed appliances. The transverse dental changes achieved in HA phase relapsed after treatment with fixed appliances.

Associations between skeletal discrepancies, breathing pattern, and upper airway obstruction in Class III malocclusions.

OBJECTIVE: To verify the associations between sagittal and vertical skeletal discrepancies, changes in upper airways, and breathing pattern in children and adolescents with Angle Class III and Class III subdivision malocclusions. METHODS: Eighty-five children and adolescents with a mean age of 9.5 ± 1.74 years were selected. Cephalometry assessed the sagittal relationship (AO-BO measurement), facial types (Ricketts VERT index), nasopharynx, and oropharynx. An otorhinolaryngologist analyzed the breathing pattern and upper airway obstruction during anamnesis, physical examination, anterior rhinoscopy, and nasofibroscopy. Medical records were also reviewed. For statistical analysis, ordinary one-way ANOVA, Kruskal-Wallis (Tukey's post-hoc), unpaired t-test, Pearson's correlation, chi-square, and Fisher's exact tests (p < 0.05) were used. RESULTS: The nasopharyngeal cephalometric dimension and pharyngeal tonsil hypertrophy were associated, whereas the oropharyngeal cephalometric dimension and palatine tonsils hypertrophy were not. Sagittal discrepancies were associated with septum deviation, while facial type was associated with inferior turbinate and palatine tonsils hypertrophy. However, facial type was not associated with breathing pattern, septum deviation, and pharyngeal tonsils hypertrophy. CONCLUSIONS: Sagittal discrepancies and type of malocclusion were not associated with breathing pattern and changes in upper airways, except for the severity of septum deviation and Class III malocclusions, which were associated with large sagittal discrepancies. Although the facial types analyzed presented signs of airway obstruction, the highest prevalence of inferior turbinate and palatine tonsils hypertrophy were found in patients with dolichofacial type.

Evaluation of the stability of treatment with Herbst appliance associated with Hyrax expander and fixed orthodontics through counterpart analysis: A longitudinal follow-up study.

OBJECTIVE: The aim of this study was to evaluate the stability of treatment with a Herbst appliance associated with Hyrax expander (Stage I), followed by fixed appliances (Stage II) and follow-up for an average of 4 years after Stage II, on dentoskeletal facial structures. METHODS: This study involved 50 adolescents with Angle Class II division 1 malocclusion associated with mandibular retrognathism: Treated Group (TG-25) and Control Group (CG-25). Lateral cephalometric radiographs were taken: T1, immediately before Stage I (TG) or at the beginning of the follow-up period (CG); T2, at the end of Stage I (TG) or the follow-up period (CG); T3, at the end of Stage II (TG); and T4, on average, 4 years after Stage II (TG). Enlow's counterpart analysis and some cephalometric measurements were evaluated. Parametric and non-parametric tests were used (P ≤ 0.05). RESULTS: The ramus alignment variables (P < 0.001), SNB (0.040), ANB (<0.001), 1.PP (P = 0.015), 1.MP (P < 0.001), ms/RLp (P < 0.001), mi/RLp (P < 0.001) and S-LS (P = 0.005) showed differences between TG and CG from T1 to T2. Longitudinally, there were differences in ramus alignment, P = 0.003, T1 > T2 < T3 = T4; SNB, P = 0.016, T1 < T2 = T3 = T4; ANB, P < 0.001, T1 > T2 = T3 = T4; 1.MP, P < 0.001, T1 < T2 = T3 = T4; ms/RLp, P = 0.002, T1 = T2 < T3 = T4; mi/RLp, P < 0.001, T1 < T2 = T3 = T4; S-LS, P < 0.001, T1 > T2 = T3 = T4 and S-LI, P = 0.003, T1 = T2 = T3 > T4. CONCLUSION: The nasomaxillary complex (MCF/PM alignment) tended to a retrusive effect to compensate the degree of mandibular retrusion. The protrusive effect of the lower facial third was evident after the Herbst stage and did not remain stable in the follow-up. The dentoalveolar compensation and improvement in facial profile remained stable.

Intrusion of overerupted periodontally compromised posterior teeth using orthodontic mini implants: A mechanobiological finite element study.

INTRODUCTION: The intrusion of posterior teeth had been considered challenging up to the development of orthodontic mini implants. In periodontally compromised teeth, the challenge is even greater, because of the root resorption risk due to periodontal ligament over-compression. Still, the precise strategy to determine the force reduction level remains uncertain. OBJECTIVE: The objective of the study was to determine, by a finite element analysis (FEA), the force reduction needed to avoid root resorption and maintain the efficiency of orthodontic mechanics of periodontally compromised teeth similar to the sound one. METHODS: An anatomical model was constructed representing a premolar inserted into a maxillary bone. Based on the initial model (R0), three bone height loss conditions were simulated (R2 = 2 mm, R4 = 4 mm, and R6 = 6 mm). Two intrusive movements were simulated: pure intrusion (bilateral mini implant) and uncontrolled-tipping intrusion (buccal mini implant). The hydrostatic stress at the periodontal ligament was used to evaluate the risk of root resorption due to over-compression. RESULTS: For bilateral mini implant intrusion, the force had to be decreased by 16%, 32% and 48% for R2, R4 and R6, respectively. For buccal mini implant intrusion, the required reductions were higher (20%, 36% and 56%). A linear relationship between the intrusive force reduction and the alveolar bone height loss was observed in both intrusion mechanics. CONCLUSIONS: According to the FE results, 8% or 9.3% of force reduction for each millimetre of bone height loss is suggested for intrusion with bilateral or buccal mini implant, respectively. The buccal mini implant anchorage must be associated with a supplemental strategy to avoid buccal crown tipping.

Temporomandibular joint articular disc position and shape in skeletal Class III.

OBJECTIVE: To compare the position and shape of the temporomandibular joint (TMJ) articular disc among the sagittal and vertical skeletal patterns in Angle Class III, Class III subdivision malocclusion and normal occlusion. The null hypothesis was that there was no difference in disc position and shape in different (1) malocclusions and (2) skeletal patterns. METHODS: This cross-sectional observational study evaluated 105 patients divided into 3 groups: Class III (33, 9.39 ± 1.96 years), Class III subdivision (45, 9.51 ± 1.59 years) and a normal occlusion (27, 10.24 ± 0.87 years) was included as healthy control. Severity of the maxilla-mandibular anteroposterior discrepancy and vertical facial pattern were determined using 2D cephalometry, and the position and shape of the articular discs were evaluated in magnetic resonance images. Statistical parametric and non-parametric tests and Kappa analysis for intra-observer and inter-observer assessment were used (p ≤ .05). RESULTS: Significant between-group differences were found in articular disc position. In the normal occlusion group, all the articular discs were well positioned. In Class III and Class III subdivision, the discs were displaced in 30.3% and 12.2% of the TMJs, respectively. Sagittal and vertical skeletal patterns did not affect the findings significantly. The Class III subdivision malocclusion group is probably different from the other groups, showing 97.7% of biconcave discs in both TMJs. CONCLUSION: The longitudinal follow-up of this sample becomes relevant as the two groups with malocclusion in the pre-peak phase of pubertal growth showed differences in the prevalence of displacement and form of the articular disc, with no association with their vertical facial characteristics.

Dehiscence and buccal bone thickness after rapid maxillary expansion in young patients with unilateral cleft lip and palate.

INTRODUCTION: The present study aimed to evaluate the consequences of rapid maxillary expansion in the buccal bone thickness and dehiscence of subjects with unilateral cleft lip and palate. METHODS: This prospective cohort study consisted of 30 participants, 20 males and 10 females, between 8 and 15 years old. Participants were allocated into 3 groups, according to the type of maxillary constriction, and were treated with different types of expanders: G1, hyrax; G2, fan-type; G3, inverted mini-hyrax. Cone-beam computed tomography scans were performed immediately before treatment and after 90 days of retention. Linear measurements were obtained by the same calibrated and blinded examiner. RESULTS: An average of 0.8 mm decrease in buccal bone thickness (P <0.001) and a 0.5 mm increase in dehiscence (P <0.001) were observed. There was no significant difference between the cleft and noncleft side for all variables (P >0.05), as there was no significant difference between groups (P >0.05). CONCLUSION: The findings in this study allow the conclusion that the orthopedic forces of rapid maxillary expansion lead to a decrease in the posterior buccal bone volume in unilateral cleft lip and palate patients.

Evaluation of the three-dimensional (3D) position of cervical vertebrae in individuals with unilateral posterior crossbite.

OBJECTIVE: To evaluate the three-dimensional (3D) position of the cervical vertebrae of growing subjects with unilateral posterior crossbite (UPC). MATERIALS AND METHODS: In this cross-sectional study, cone beam computed tomography (CBCT) scans of 1455 patients were screened, and ultimately 58 scans (26 patients with UPC and 32 controls with normal occlusion) were included after imposing inclusion/exclusion criteria. Roll, yaw, and deviation of the geometric center of C1, C2, and C3 vertebrae were measured and compared between groups. A correlation between these parameters and different variables on mandibular positioning was also carried out. RESULTS: A statistically significant difference (p < 0.05) was observed between groups for the deviation of pogonium (Pog), mandibular plane roll, and C3 roll, and patients with UPC showed higher cant or deviation. A significant correlation was reported for the roll of C2 and C3 with the deviation of Pog, a roll of the occlusal plane, and roll of the mandibular plane (p < 0.05). The greater the deviation of the Pog to one side, the greater the roll of the vertebrae with this same side up. The same tendency was observed between the roll of the occlusal plane or the mandibular plane with the roll of these cervical vertebrae. CONCLUSIONS: There is a positive correlation between transverse occlusal changes and positional deviations of the cervical vertebrae, especially C2 and C3. CLINICAL RELEVANCE: The study results do not allow us to infer the clinical/functional consequences of these deviations, as well as if malocclusion's treatment would result in an improvement of intervertebral relationships.

Validity and reliability of a trigonometry-based method for the measurement of tooth movement on digital models.

OBJECTIVE: The objectives of the present study were to develop a method for longitudinally measuring tooth rotation, inclination and angulation on digital models, and to test the method validity and reliability. METHODS: The initial and final planned models of 14 patients treated with Invisalign® (386 teeth) were exported from ClinCheck®. The rotation, inclination and angulation values were assessed for the incisors, canines, premolars and molars, in both models, using trigonometry. An application was developed in Python 2.7 to automate the measurements. The ∆planned (variation in the position between the initial and final planned models) was obtained for each tooth and each type of movement. To test the validity, the degree of agreement between the ∆planned and the values available in the Invisalign® Table of Movements was assessed using the Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis. For intra and inter-rater reliabilities, the ∆planned was obtained again. RESULTS: Excellent ICCs (> 0.9) and limits of agreement with narrow and clinically acceptable discrepancies were obtained for the rotation of all teeth (except maxillary canines, which had broader limits: -3.47 - 5.43) and for the inclination of premolars and molars. The inclination of anterior teeth and angulation of all teeth had ICCs and limits that were not indicative of great agreement. The reliability was high for the three movements (discrepancy <2°). CONCLUSIONS: The method developed is reliable and suitable for longitudinally measuring inclination (posterior teeth) and rotation (except maxillary canines). It has limited value for the other movements measurements.

Validity and reliability of a trigonometry-based method for the measurement of tooth movement on digital models

ABSTRACT Objective: The objectives of the present study were to develop a method for longitudinally measuring tooth rotation, inclination and angulation on digital models, and to test the method validity and reliability. Methods: The initial and final planned models of 14 patients treated with Invisalign® (386 teeth) were exported from ClinCheck®. The rotation, inclination and angulation values were assessed for the incisors, canines, premolars and molars, in both models, using trigonometry. An application was developed in Python 2.7 to automate the measurements. The ∆planned (variation in the position between the initial and final planned models) was obtained for each tooth and each type of movement. To test the validity, the degree of agreement between the ∆planned and the values available in the Invisalign® Table of Movements was assessed using the Intraclass Correlation Coefficient (ICC) and Bland-Altman analysis. For intra and inter-rater reliabilities, the ∆planned was obtained again. Results: Excellent ICCs (> 0.9) and limits of agreement with narrow and clinically acceptable discrepancies were obtained for the rotation of all teeth (except maxillary canines, which had broader limits: -3.47 - 5.43) and for the inclination of premolars and molars. The inclination of anterior teeth and angulation of all teeth had ICCs and limits that were not indicative of great agreement. The reliability was high for the three movements (discrepancy <2°). Conclusions: The method developed is reliable and suitable for longitudinally measuring inclination (posterior teeth) and rotation (except maxillary canines). It has limited value for the other movements measurements.

RESUMO Objetivo: Os objetivos do presente estudo foram desenvolver um método para medir longitudinalmente a rotação, inclinação e angulação dentárias em modelos digitais, e testar sua validade e reprodutibilidade. Material e Métodos: Os modelos inicial e final planejado de 14 pacientes tratados com Invisalign® (386 dentes) foram exportados do ClinCheck®. Os valores de rotação, inclinação e angulação foram calculados para incisivos, caninos, pré-molares e molares, em ambos os modelos, por meio de trigonometria. Um aplicativo desenvolvido em Python 2.7 foi utilizado para automatização das medidas. O ∆planejado (variação na posição entre os modelos inicial e final planejado) foi obtido para os movimentos descritos, nos diferentes grupos de dentes. A validade do método foi verificada pelo grau de concordância entre o ∆planejado e os valores disponíveis na Tabela de Movimentos do Invisalign®, utilizando-se o Coeficiente de Correlação Intraclasse (ICC) e a análise de Bland-Altman. O ∆planejado foi novamente calculado para análise da reprodutibilidade intra e interexaminadores. Resultados: Excelentes ICCs (> 0,9) e limites de concordância com discrepâncias reduzidas e clinicamente aceitáveis foram obtidos para a rotação de todos os dentes (exceto os caninos superiores, que expressaram limites mais amplos: -3,47 - 5,43) e para a inclinação de pré-molares e molares. A inclinação dos dentes anteriores e a angulação de todos os dentes apresentaram ICCs e limites não representativos de boa concordância. A reprodutibilidade foi alta para os três movimentos (discrepância < 2°). Conclusões: O método desenvolvido é reprodutível e se mostrou adequado para mensuração longitudinal da inclinação de dentes posteriores e rotação de todos os dentes, exceto caninos superiores. Apresenta valor limitado para as demais mensurações.

The influence of educational measures and low-level laser phototherapy on temporomandibular disorders: Study protocol clinical trial (SPIRIT Compliant).

Photobiomodulation therapy (PBMT) with low-power laser is used for pain relief in several clinical conditions, including temporomandibular disorders (TMD). As musculoskeletal pain often produces changes in motor behavior, it is common for patients with TMD to present limited mandibular movements. To the date, there is no consensus about the optimal dosimetric parameters of PMBT for TMD. This randomized, controlled, double-blind clinical trial aims to evaluate pain relief and mandibular mobility in patients with TMD following treatments with 2 laser wavelengths, red (660 nm) and infrared (808 nm) individually and in combination as compared to a placebo treatment. One-hundred participants presenting myalgia and arthralgia, with disk displacement or not, will be selected based on the Research Diagnostic Criteria for Temporomandibular Disorders. All participants will be instructed about the etiology, prognosis, and self-care techniques for pain control on TMD, and followed up for 2 weeks. After this period, those who still present pain score over 4 in a visual analog scale (VAS) will be included in the study. Participants will be randomly assigned to 4 treatment groups: G1 = placebo (SHAM); G2 = PBMT with red laser (660 nm, 0.034 cm, 88 J/cm, 100 mW, 3 J/point); G3 = PBMT with infrared laser (808 nm, 0.034 cm, 88 J/cm, 100 mW, 3 J/point); and G4 = PBMT with red and infrared laser alternated between sessions. The treatment consists of 8 sessions, 2 times a week. The effect of the proposed therapies will be measured by: pain reduction in VAS; pressure pain threshold on TMJ, masseter and temporal muscles; and the amplitude of mandibular movements (opening, protrusion, and right and left lateral movements). The data will be collected at the following times: initial (T1), after the 1st treatment session (T2), at the end of treatment (T3), and 30 days after the last PBMT session (T4). For statistical analysis will be used 2-way repeated measures analysis of variance test, complemented by a post hoc Tukey test (P < .05).

Effect of the software binning and averaging data during microcomputed tomography image acquisition.

This study describes the effect of the software binning and data averaging during micro CT volume acquisition, on the assessment of root resorption volumes. The mesial roots (n = 9), after orthodontic tooth movement during 14 days, were scanned, using a micro CT system (9 µm/pixel). All roots were reconstructed and the volumes of the resorption lacunae evaluated. The height and width of the pixels vary according to the parameters (A1, A2, A3, A4, A5, A6, A7, A8, A9) used during the scan. In the root #1 the mean volumes of resorption were similar in A4 and A7; in the root #2 there was no similarity in the mean volumes of resorption in any of the parameters; in root #3 only A4 presented mean volume different from zero (3.05 × 10°). In the root #5, the A1 and A7 presented similar mean volumes and in the A6 and A9 presented near mean volumes. In the root #9 the A1, A4, and A7 presented similar mean volumes and A6 and A9 also had similar mean volumes. Significant difference was detected in the volume of resorption among the roots #2, #5 and #9 (p = 0.04). When analyzing delicate structures such as the roots of rats' molars, the variation of such parameters will significantly influence the results.

Infrared Light-Emitting Diode (LED) Effects on Orthodontic Tooth Movement.

The present study aimed to analyze the effect of LED phototherapy on the presence of hyalinization and root resorption during orthodontic tooth movement (OTM) in rats and to measure the amount of tooth movement. Eighty rats were allocated into two groups: LED and control (CON), where the LED rats were irradiated with infrared LED (850 nm, 30 mW) for 5 min during the first five days of OTM and where controls were not irradiated. Both groups were subdivided into four subgroups (n=10) according to the date of euthanasia (4, 7, 14 and 21 days). Five out of ten LED21 and five of ten CON21 rats were submitted to micro-computed tomography (µCT); µCT scans were taken on days 0, 7, 14 and 21. For histological study, maxillae were processed to light microscopy using Hematoxylin-Eosin (HE) and Tartrate-Resistant Acid Phosphatase (TRAP) histochemistry. The amount of tooth movement did not differ between LED and CON. Hyalinization was observed at the pressure areas in both groups, and it did not show a statistically significant difference between the groups. Root resorption was also observed in both groups after 7 days and it did not represent any differences between the two groups. LED phototherapy was not able to increase the amount of OTM. Similar characteristics of hyalinization and root resorption were observed in both groups.

Infrared light-emitting diode (led) effects on orthodontic tooth movement

Abstract The present study aimed to analyze the effect of LED phototherapy on the presence of hyalinization and root resorption during orthodontic tooth movement (OTM) in rats and to measure the amount of tooth movement. Eighty rats were allocated into two groups: LED and control (CON), where the LED rats were irradiated with infrared LED (850 nm, 30 mW) for 5 min during the first five days of OTM and where controls were not irradiated. Both groups were subdivided into four subgroups (n=10) according to the date of euthanasia (4, 7, 14 and 21 days). Five out of ten LED21 and five of ten CON21 rats were submitted to micro-computed tomography (μCT); μCT scans were taken on days 0, 7, 14 and 21. For histological study, maxillae were processed to light microscopy using Hematoxylin-Eosin (HE) and Tartrate-Resistant Acid Phosphatase (TRAP) histochemistry. The amount of tooth movement did not differ between LED and CON. Hyalinization was observed at the pressure areas in both groups, and it did not show a statistically significant difference between the groups. Root resorption was also observed in both groups after 7 days and it did not represent any differences between the two groups. LED phototherapy was not able to increase the amount of OTM. Similar characteristics of hyalinization and root resorption were observed in both groups.

Resumo O presente estudo tem como objetivo analisar o efeito da fototerapia LED na presença da hialinização e reabsorção radicular durante o movimento dentário ortodôntico (MDO) em ratos, e a mensuração da quantidade de movimento dentário. Oitenta ratos foram alocados em dois grupos: LED e Controle (CON), os ratos foram irradiados com um LED infravermelho (850nm, 30mW) por 5 minutos durante os cinco primeiros dias da MDO; e o grupo controle não foi irradiado. Ambos os grupos foram subdivididos em 4 subgrupos (n=10) de acordo com a data da eutanásia (4, 7, 14 e 21 dias). Cinco dos dez ratos LED21 e cinco dos dez ratos CON21foram submetidos a microtomografia computadorizada (μCT); As μCT foram realizadas nos dias 0, 7, 14 e 21. Para o estudo histológico, as maxilas foram processadas para microscopia de luz, usando hematoxilina-eosina (HE) e Fosfatase ácido Tartrate-Resistente (TRAP) para histoquímica. A quantidade de movimento dentário não diferiu entre o LED e o CON. A hialinização foi observada nas áreas de pressão em ambos os grupos e não mostrou diferença estatisticamente significante. Reabsorção radicular também foi observada em ambos os grupos depois de 7 dias e não houve diferença entre os grupos. A fototerapia LED não aumentou a quantidade de MDO. Características similares de hialinização e reabsorção radicular foram observadas em ambos os grupos