Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

Bonding positional accuracy of attachments and marginal adaptation of in-house aligners - A quality improvement laboratory study.

OBJECTIVES: To evaluate the 3D accuracy of attachment positioning and the adaptation of aligners to attachments using in-house templates made with either polyethylene terephthalate glycol (PETG) or ethylene-vinyl acetate (EVA) and either pressure or vacuum thermoforming machines. MATERIALS AND METHODS: Overall, 140 test specimens were resin-printed. Templates for the attachment bonding were made with 1-mm EVA or 0.5-mm PETG laminates. Orthodontic aligners were manufactured with 0.75-mm PETG. The thermoplastification process was carried out using either vacuum or pressure machines. The positional differences between the virtual and bonded attachments were assessed in the X, Y and Z coordinates. The marginal adaptation between the aligners and the attachments was measured. RESULTS: Minor inaccuracies in the positioning of the attachments were observed in all combinations of thermoforming machines and plastic laminates used to fabricate the templates, mainly in the superior-inferior (Z) dimension. PETG performed better than EVA in the anterior region (p < .05). No association was found between thermoplastification machines and the accuracy of the positioning of the attachments (p > .05). While small misadaptations between the aligners and the attachments were observed, the EVA templates performed better than the PETG templates. CONCLUSIONS: The inaccuracy of the attachment positioning and the misadaptation of the aligners to the attachments were slight. The vacuum and pressure thermoplastification machines showed no difference in attachment positioning accuracy. The PETG template was better than the EVA template in the anterior region, but the EVA attachments presented a better adaptation to the aligners than the PETG attachments.

Long-term effects produced by early treatment of Class III malocclusion with rapid maxillary expansion and facemask followed by fixed appliances: A multicentre retro-prospective controlled study.

OBJECTIVE: To assess the short- and long-term dentoskeletal effects of early Class III treatment with rapid maxillary expansion and facemask (RME/FM) followed by fixed appliances. MATERIALS AND METHODS: A total of 44 patients (27 females, 17 males) treated consecutively with RME/FM were included from the archives of 3 centres. Three lateral cephalograms were available: T0 (before the start of RME/FM therapy, mean age 8.1 ± 1.8 years), T1 (immediately after RME/FM, mean age 9.8 ± 1.6 years), and T2 (long-term observation, mean age 19.5 ± 1.6 years). A control group of 17 untreated Class III subjects (12 females and 5 males) also was selected. Between-group statistical comparisons were performed with ANCOVA. RESULTS: No statistically significant differences for any of the cephalometric variables were found at T0. In the short term, the treated group showed significant improvements in ANB (+2.9°), Wits appraisal (+2.7 mm), SNA (+1.8°) and SNB (-1.1°). A significant closure of CoGoMe angle (-1.3°) associated with smaller increments along Co-Gn (-2.4 mm) also was found together with a significant increase in intermaxillary divergence (+1.3°). In the long-term, significant improvements in ANB (+2.6°), Wits appraisal (+2.7 mm) and SNB (-1.7°) were recorded together with a significant closure of the CoGoMe angle (-2.9°). No significant long-term changes in vertical skeletal relationships were found. CONCLUSIONS: RME/FM therapy was effective in improving Class III dentoskeletal relationships in the short term. These changes remained stable in the long-term due mainly to favourable mandibular changes.

Comparison between digital and conventional impression techniques in children on preference, time and comfort: A crossover randomized controlled trial.

OBJECTIVE: To compare the conventional alginate impression and the digital impression taken with an intraoral scanner of both dental arches in children, using a randomized crossover design. TRIAL DESIGN: This is a monocentric, controlled, superiority, randomized, crossover, open study. METHODS: Twenty-four orthodontic patients between 6 and 11 years of age underwent intraoral scanning (TRIOS 3; 3Shape) and alginate impression of both dental arches with an interval of 1 week between the two procedures. Participants were recruited from September 2021 to March 2022 and the study was completed in April 2022. Impression time for the two procedures was compared. Patients were asked which one of the two impression procedures they preferred. A questionnaire including Visual Analogue Scale (VAS) for comfort, pain, gag reflex and difficulty in breathing, was administered to the patients. RESULTS: Eighteen out of 24 patients preferred digital impression (75%, 95% confidence interval [CI]: 55% to 88%; P = .014). Scanning time was significantly shorter than alginate impression time (difference -118 seconds; 95% CI: -138 to -99; P < .001). Comfort was significantly higher for digital impression (difference 1.7; 95% CI: 0.5 to 2.8; P = .007). There was no difference in pain (difference -0.2; 95% CI: -1.5 to 1.0; P = .686) while gag reflex and breathing difficulties were smaller for digital impression (gag reflex difference -2.5; 95% CI: -4.0 to -0.9; P = .004 and breathing difficulties difference -1.5; 95% CI: -2.5 to -0.5; P = -.004). CONCLUSIONS: Digital impression is preferred by children aged 6-11 years and it is significantly faster in acquisition time than conventional alginate impression. REGISTRATION: The study was registered on ClinicalTrials.gov with registration number NCT04220957 on January 7th, 2020 (https://clinicaltrials.gov/ct2/show/NCT04220957).

Three-dimensional changes of the upper airway in patients with Class II malocclusion treated with the Herbst appliance: A cone-beam computed tomography study.

INTRODUCTION: This study aimed to determine the volumetric effects on the upper airways of growing patients with Class II malocclusion treated with the Herbst appliance (HA). METHODS: Volumetric measurements of the upper airways of 42 skeletal Class II malocclusion patients (mean age: 13.8 ± 1.2 years; ranging from 12.0 to 16.9 years) were assessed using cone-beam computed tomography scans acquired before treatment (T0) and approximately 1 year later (T1). The sample comprised a Herbst appliance group (HA group [HAG]; n = 24), and a comparison group (comparison group [CG]; n = 18) of orthodontic patients who had received dental treatments other than mandibular advancement with dentofacial orthopedics. RESULTS: In CG, nasopharynx and oropharynx volumes decreased slightly during the observation period (9% and 3%, respectively), whereas the nasal cavity volume increased significantly (12%; P = 0.046). In HAG, there was an increase in the volume of all regions (nasal cavity, 5.5%; nasopharynx, 11.7%; and oropharynx, 29.7%). However, only the oropharynx showed a statistically significant increase (P = 0.003), presenting significant volumetric changes along the time (T1-T0) in HAG. CONCLUSION: Mandibular advancement with the HA significantly increased the volume of the oropharynx, but no significant volumetric modifications were observed in the nasal cavity and nasopharynx.

Development and validation of a prediction model for long-term unsuccess of early treatment of Class III malocclusion.

AIM: To develop and validate a prediction model to forecast long-term stability of early treatment with rapid maxillary expansion (RME) and facemask (FM) in a large sample of Class III growing patients. METHODS: The Brazilian Group (BG) consisted of 73 consecutively treated Caucasian Class III patients (41 females and 32 males). Mean age at T0 (before treatment) was 7.1 ± 1.6 years, while mean age at T1 (long-term follow-up) was 21.8 ± 3.2 years. The Italian Group (IG, validation cohort) comprised 28 consecutively treated Caucasian Class III patients (14 females and 14 males, mean age at T0 9.0 ± 1.3 years and mean age at T1 18.2 ± 1.4 years). Cephalometric analysis was performed on lateral cephalograms at T0. Gender and cephalometric variables, chronologic age, and dentition phase at T0 were used as predictors for long-term unsuccessful treatment at T1. All predictors for unsuccessful treatment in the BG were subjected to bivariate logistic regression. Only those statistically significant predictors in the bivariate logistic regression entered mixed stepwise logistic regression with P = 0.05 to enter and to leave. The validity of the prediction model derived from the BG was then tested on the IG. RESULTS: The prediction model consisted of only one cephalometric variable: the angle between the Condylar Axis and the Mandibular Plane (CondAx-MP) (odds ratio: 1.52, 95% confidence interval: 1.25-1.85, P < 0.0001). Unsuccessful treatment at T1 was predicted for values of CondAx-MP at T0 greater than the cut-off value of 147.8 degrees. BG patients predicted incorrectly were 3 out of 22 for the unsuccessful cases and 1 out of 51 for the successful cases. Therefore, accuracy was 0.95, sensitivity 0.86, specificity 0.98, and positive and negative predictive values were 0.95 and 0.94. When the predictive model was applied on IG, all five unsuccessful cases were predicted correctly, while only 1 out of 23 successful patients was predicted incorrectly. CONCLUSION: CondAx-ML was identified as a reliable predictor for long-term stability of early Class III treatment with RME and FM.

Condyle-glenoid fossa relationship after Herbst appliance treatment during two stages of craniofacial skeletal maturation: A retrospective study.

OBJECTIVES: To perform a three-dimensional evaluation of the position of the condyles in patients treated with Herbst appliance (HA) in two stages of cervical vertebral maturation. SETTING AND SAMPLE POPULATION: Retrospective case-control study. Pubertal Herbst group (PHG; n = 24, mean age 14.5 years, CS 3 and CS 4) and pre-pubertal Herbst group (PPHG; n = 17, mean age 9.9 years, CS 1 and CS 2) were contrasted with comparison groups of non-orthopaedically treated Class II patients in pubertal (PCG; n = 17, mean age 13.9 years) and pre-pubertal maturational stages (PPCG; n = 18, mean age 10.6 years). MATERIALS AND METHODS: Cone-beam computer tomography scans were taken before treatment (T0) and at T1 after 8 to 12 months. Point-to-point measurements of the displacement of the condyles between T0 and T1, relative to the glenoid fossae, were performed in the X, Y, Z and 3D perspectives. Qualitative assessments using semi-transparent overlays and colour mapping also were produced. RESULTS: The displacement of the condyles within the glenoid fossae in the treated groups was small (<0.75 mm; P > .05). Relative to the glenoid fossa, condylar position at T1 was similar to T0 in pre-pubertal and pubertal groups (P > .05). Similar condylar rotations from T0 to T1 were observed in Herbst and comparison groups, and no significant difference was found between pre-pubertal and pubertal patients. CONCLUSIONS: Regardless the stage of skeletal maturation, HA treatment did not change the condyle-glenoid fossa relationship.

Common 3-dimensional coordinate system for assessment of directional changes.

INTRODUCTION: The aims of this study were to evaluate how head orientation interferes with the amounts of directional change in 3-dimensional (3D) space and to propose a method to obtain a common coordinate system using 3D surface models. METHODS: Three-dimensional volumetric label maps were built for pretreatment (T1) and posttreatment (T2) from cone-beam computed tomography images of 30 growing subjects. Seven landmarks were labeled in all T1 and T2 volumetric label maps. Registrations of T1 and T2 images relative to the cranial base were performed, and 3D surface models were generated. All T1 surface models were moved by orienting the Frankfort horizontal, midsagittal, and transporionic planes to match the axial, sagittal, and coronal planes, respectively, at a common coordinate system in the Slicer software (open-source, version 4.3.1; http://www.slicer.org). The matrix generated for each T1 model was applied to each corresponding registered T2 surface model, obtaining a common head orientation. The 3D differences between the T1 and registered T2 models, and the amounts of directional change in each plane of the 3D space, were quantified for before and after head orientation. Two assessments were performed: (1) at 1 time point (mandibular width and length), and (2) for longitudinal changes (maxillary and mandibular differences). The differences between measurements before and after head orientation were quantified. Statistical analysis was performed by evaluating the means and standard deviations with paired t tests (mandibular width and length) and Wilcoxon tests (longitudinal changes). For 16 subjects, 2 observers working independently performed the head orientations twice with a 1-week interval between them. Intraclass correlation coefficients and the Bland-Altman method tested intraobserver and interobserver agreements of the x, y, and z coordinates for 7 landmarks. RESULTS: The 3D differences were not affected by the head orientation. The amounts of directional change in each plane of 3D space at 1 time point were strongly influenced by head orientation. The longitudinal changes in each plane of 3D space showed differences smaller than 0.5 mm. Excellent intraobserver and interobserver repeatability and reproducibility (>99%) were observed. CONCLUSIONS: The amount of directional change in each plane of 3D space is strongly influenced by head orientation. The proposed method of head orientation to obtain a common 3D coordinate system is reproducible.

Dental arch dimensional changes after adenotonsillectomy in prepubertal children.

INTRODUCTION: The purposes of this study were to investigate the dental arch changes after adenotonsillectomies in prepubertal children and to compare the dental arch dimensions of mouth-breathing and nasal-breathing children. METHODS: The sample included 49 prepubertal severely obstructed mouth-breathing children and 46 prepubertal nasal-breathing children. Twenty-four of the 49 mouth-breathing children had an adenotonsillectomy and composed the adenotonsillectomy subgroup. The 25 children in whom the mouth-breathing pattern was unchanged during the 1-year study period composed the control subgroup. RESULTS: The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children. After airway clearance, the adenotonsillectomy group showed a significant maxillary transverse width gain compared with the control subgroup. The control subgroup showed a significant deepening of the palatal height when compared with the adenotonsillectomy subgroup after 1 year. CONCLUSIONS: The adenotonsillectomy subgroup had a significantly different pattern of arch development compared with the untreated controls. After adenotonsillectomy, the mouth-breathing children showed greater maxillary transverse development than did the controls. The palatal vault deepened in the untreated children. The mouth-breathing children showed a deeper palatal vault, a larger mandibular width, and a larger mandibular arch length in comparison with the nasal-breathing children.

The effect of micro-osteoperforations on the rate of maxillary incisors' retraction in orthodontic space closure: a randomized controlled clinical trial.

BACKGROUND: This single-centered randomized controlled clinical trial aimed to evaluate the effectiveness of micro-osteoperforations (MOPs) in accelerating the orthodontic retraction of maxillary incisors. METHODS: Forty-two patients aged 16-40 were recruited and randomly assigned into two groups, one which underwent MOPs (MOPG) in the buccal and palatal region of all maxillary incisors immediately before the start of retraction and one which did not (CG). Eligibility criteria included the orthodontic need for maxillary first premolars extraction and space closure in two phases. The primary outcome of the study consisted of measuring the rate of space closure and, consequently, the rate of incisors' retraction using digital model superimposition 14 days later and monthly thereafter for the next 4 months. The secondary outcomes included measuring anchorage loss, central incisors' inclination, and root length shortening, analyzed using cone beam computed tomography scans acquired before retraction and 4 months after retraction. Randomization was performed using QuickCalcs software. While clinical blinding was not possible, the image's examinator was blinded. RESULTS: Twenty-one patients were randomly assigned to each group. However, due to various reasons, a total of 37 patients (17 male and 20 female) were analyzed (mean age: 24.3 ± 8.1 years in the MOPG; 22.2 ± 4.2 years in the CG) during the trial. No statistically significant difference was found between the MOPG and the CG regarding the incisors' retraction measured at different time points at the incisal border (14 days, 0.4 mm vs. 0.5 mm; 1 month, 0.79 mm vs. 0.77 mm; 2 months, 1.47 mm vs. 1.41 mm; 3 months, 2.09 mm vs. 1.88 mm; 4 months, 2.62 mm vs. 2.29 mm) and at the cervical level (14 days, 0.28 mm vs. 0.30 mm; 1 month, 0.41 mm vs. 0.32 mm; 2 months, 0.89 mm vs. 0.61 mm; 3 months, 1.36 mm vs. 1.10 mm; 4 months, 1.73 mm vs. 1.39 mm). Similarly, no statistically significant differences were detected in the space closure, anchorage loss, central incisors' inclination, and radicular length between groups. No adverse effect was observed during the trial. CONCLUSIONS: MOPs did not accelerate the retraction of the maxillary incisors, nor were they associated with greater incisor inclination or root resorption. Trial registration ClinicalTrials.gov NCT03089996. Registered 24 March 2017- https://clinicaltrials.gov/ct2/show/NCT03089996 .

Is the growth pattern in mouth breathers comparable with the counterclockwise mandibular rotation of nasal breathers?

INTRODUCTION: The aim of this longitudinal study was to investigate mandibular rotation and angular remodeling in mouth-breathing children compared with nasal-breathing children. METHODS: The sample included 55 severely obstructed mouth-breathing children (mean age, 6.1 years) and 55 nasal-breathing children (mean age, 7.3 years). The cephalograms at baseline and after 1 year were traced and measured, and superimpositions were made to determine true mandibular rotation, apparent rotation, and angular remodeling. The significance level was set at 5%. RESULTS: The mouth-breathing children had a longer face cephalometric pattern compared with nasal-breathing children. No cranial deflection differences were observed. No changes in the vertical growth pattern were observed during the 1-year period in either group. There were no statistically significant differences between the groups regarding apparent rotation (mouth breathing, -0.54°, vs nasal breathing, -0.41°). In comparison with the nasal breathers, the mouth breathers showed statistically significant lower yearly rates of counterclockwise true rotation (mouth breathing, -0.60°, vs nasal breathing, -1.31°) and angular remodeling (mouth breathing, 0.06°, vs nasal breathing, 0.87°). CONCLUSIONS: Mouth-breathing children had a hyperdivergent cephalometric pattern, but against all expectations, counterclockwise true mandibular and apparent rotations were the average observations. Mouth-breathing children showed less true rotation and angular remodeling than did nasal breathers; however, apparent rotations were similar.

Two-phase orthodontic treatment of a complex malocclusion: giving up efficiency in favor of effectiveness, quality of life, and functional rehabilitation?

The interceptive orthodontic treatment of patients with complex dentofacial abnormalities is frequently inefficient and produces less than ideal outcomes. Therefore, postponing therapy to a single-phase surgical-orthodontic approach might be considered a reasonable option. However, other relevant aspects of the patient's quality of life, such as possible psychosocial problems and functional impairments, should also be considered before deciding whether to intercept a severe dentofacial malocclusion while the patient is still growing, or wait and treat later. This case report describes the nonsurgical treatment of a young patient with a severe Class III open-bite malocclusion associated with a cervical cystic lymphangioma. Despite the poor interceptive therapy prognosis, a 2-phase approach was effective. A reflection about giving up efficiency in favor of effectiveness, functional rehabilitation, and the patient's quality of life is included.

Effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cements.

The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups.

Craniofacial morphology of patients with unilateral cleft lip and palate at two stages of skeletal maturation.

The aim of this retrospective cross-sectional investigation was to perform a 3D analysis of craniofacial morphology of patients with unilateral cleft lip and palate (UCLP) at two stages of skeletal maturation. Cone-beam computed tomography (CBCT) scans of 52 UCLP patients (34 prepubertal; 18 pubertal) were collected from an outpatient referral center for the treatment of craniofacial deformities. In total 15 multiplanar craniofacial landmarks were identified, 3D virtual surface models were created, and 13 variables were measured to assess the 3D Euclidean distances between landmarks and spatial position of the landmarks in the projected X, Y and Z components. Maxillary and mandibular pitch (clockwise, counterclockwise) rotation relative to the cranial base was also evaluated. The significance level was set at 5%. Maxillary retrusion value relative to the cranial base was higher and statistically significant greater (p = 0.028) in pubertal (SNA, 77.4° ± 6.2; N-ANS Y, 3.3 mm ± 3.1) than in prepubertal patients (SNA 81.0° ± 5.2; N-ANS Y, 5.8 mm ± 2.7). The posterior cranial base length (S-Ba Y) was significantly longer (p = 0.013) in pubertal (20.7 mm ± 3.4) than in prepubertal patients (18.4 mm ± 2.7). The upper facial height (N-ANS Z) was significantly greater (p = 0.01) in pubertal (46.9 mm ± 4.5) than in prepubertal patients (43.4 mm ± 3.0). Prepubertal and pubertal UCLP patients presented distinct patterns of craniofacial morphology, mainly in the sagittal component of the maxilla and in the posterior cranial base length. Pubertal patients had greater maxillary retrusion and posterior cranial base length.

Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate.

OBJECTIVES: To determine the three-dimensional changes of the nasal septum (NS), alveolar width, alveolar cleft volume, and maxillary basal bone following rapid maxillary expansion (RME) in consecutive patients with unilateral cleft lip and palate (UCLP). MATERIALS AND METHODS: A retrospective investigation was conducted based on the analysis of cone-beam computed tomography (CBCT) data of 40 consecutive patients with UCLP (mean age 11.1 ± 2.2 years). Scans were acquired prior to RME (T0) and after removal of the expander (T1) before graft surgery. A three-dimensional analysis of the effects of RME on the nasal septum, alveolar width, alveolar cleft volume, and maxillary basal bone was performed. RESULTS: No changes in the NS deviation were observed following RME (P > .05). Significant increases of the alveolar transverse dimension were found in the anterior (14.2%; P < .001) and posterior (7.7%; P < .001) regions as well as in the volume of the alveolar cleft (19.6%; P < .001). No changes in the basal bone dimensions and morphology were observed (P > .05). CONCLUSIONS: Following RME, no changes were observed in the NS and maxillary basal bones of patients with UCLP despite the significant gain in the anterior and posterior alveolar width and the increase of the alveolar cleft defect. Clinicians should be aware that maxillary changes following RME in patients with UCLP are restricted to the dentoalveolar region.

Late diagnosis of dentoalveolar ankylosis: impact on effectiveness and efficiency of orthodontic treatment.

Dentoalveolar ankylosis is a local etiologic factor of malocclusion that can have deleterious effects on normal dental development. Therefore, it is of paramount importance to diagnose the problem as early as possible so that interception can be performed at the correct time. This case report demonstrates the consequences of late diagnosis of dentoalveolar ankylosis and discusses its effects on development of the occlusion and how it can increase orthodontic biomechanical complexity and treatment time.

Superimposition of 3D maxillary digital models using open-source software.

Historically, whether for research purposes or clinical monitoring, orthodontic evaluation of dental movements has been done using plaster study models and two dimensional (2D) radiographs. However, new frontiers for the diagnosis, planning and outcome assessment of orthodontic treatments have arisen, due to the revolutionary digital tools which enable a three dimensional (3D) computerized analysis of dental movements by means of digital models. However, the software for 3D analysis are often costly, resulting in limited access to orthodontists. The present study aims to describe, through a clinical case presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics, a method for the superimposition of maxillary digital models using an open-source software to evaluate dental movements.

Are computed tomography 3D measurements of the upper airways in mouth-breathing children in agreement with the ENT clinical diagnosis of obstruction?

INTRODUCTION: Imaging studies have hystorically been used to support the clinical otorhinolaryngological evaluation of the upper respiratory tract for the diagnosis of obstructive causes of oral breathing. OBJECTIVE: The objective of this study was to compare 3D volumetric measurements of nasal cavity, nasopharynx and oropharynx of obstructed mouth-breathing children with measurements of non-obstructed mouth-breathing children. METHODS: This retrospective study included 25 mouth-breathing children aged 5-9 years evaluated by otorhinolaryngological clinical examination, flexible nasoendoscopy and full-head multi-slice computed tomography. Tomographic volumetric measurements and dichotomic otorhinolaryngological diagnosis (obstructed vs. non-obstructed) in three anatomical regions (the nasal cavity, nasopharynx and oropharynx) were compared and correlated. An independent sample t-test was used to assess the association between the 3D measurements of the upper airways and the otorhinolaryngological diagnosis of obstruction in the three anatomical regions. Inter- and intra-observer intraclass correlation coefficients were used to evaluate the reliability of the 3D measurements. RESULTS: The intra-class correlation coefficients ranged from 0.97 to 0.99. An association was found between turbinate hypertrophy and nasal cavity volume reduction (p<0.05) and between adenoid hyperplasia and nasopharynx volume reduction (p<0.001). No association was found between palatine tonsil hyperplasia and oropharynx volume reduction. CONCLUSIONS: (1) The nasal cavity volume was reduced when hypertrophic turbinates were diagnosed; (2) the nasopharynx was reduced when adenoid hyperplasia was diagnosed; and (3) the oropharynx volume of mouth-breathing children with tonsil hyperplasia was similar to that of non-obstructed mouth-breathing children. The adoption of the actual anatomy of the various compartments of the upper airway is an improvement to the evaluation method.