The inadequacy of the Y-axis of growth (SNGn) for the vertical pattern assessment in patients with sagittal discrepancies.

AIM: The aim of this cephalometric study was to evaluate the influence of the sagittal skeletal pattern on the 'Y-axis of growth' measurement in patients with different malocclusions. MATERIALS AND METHODS: Lateral head films from 59 patients (mean age 16y 7m, ranging from 11 to 25 years) were selected after a subjective analysis of 1630 cases. Sample was grouped as follows: Group 1 - class I facial pattern; group 2 - class II facial pattern; and Group 3 - class III facial pattern. Two angular measurements, SNGoGn and SNGn, were taken in order to determine skeletal vertical facial pattern. A logistic regression with errors distributed according to a binomial distribution was used to test the influence of the sagittal relationship (Class I, II, III facial patterns) on vertical diagnostic measurement congruence (SNGoGn and SNGn). RESULTS: RESULTS show that the probability of congruence between the patterns SNGn and SNGoGn was relatively high (70%) for group 1, but for groups II (46%) and III (37%) this congruence was relatively low. CONCLUSION: The use of SNGn appears to be inappropriate to determine the vertical facial skeletal pattern of patients, due to Gn point shifting throughout sagittal discrepancies. Clinical Significance: Facial pattern determined by SNGn must be considered carefully, especially when severe sagittal discrepancies are present.

Periodontal indexes of two types of 3 x 3 retainers: 0.032-in SS V-loop versus 0.0215-in SS coaxial - a randomized crossover trial.

OBJECTIVE: This randomized crossover trial evaluated periodontal indexes of two types of 3 x 3 retainers (a modified 0.032-in SS V-loop retainer and a conventional 0.0215-in SS coaxial wire retainer) after bonded for six months. Also, bonded failure rate, and a questionnaire about comfort, ease of cleaning and overall preference were recorded. MATERIAL AND METHODS: 15 patients were enrolled in this study who used both retainers for six months each, having a 15-day wash-out interval between each bonded retainer usage. The following periodontal index were recorded: Plaque Index (PI), Calculus Index (CI) and Gingival Index (GI). Patients answered a questionnaire to assess comfort, ease of cleaning and overall retainer-type preference. Rate of bonding failure was also evaluated. RESULTS: V-Loop retainer showed higher PI (P<0.05) as compared to conventional 0.0215-in coaxial wire retainer. However, CI and GI presented no statistically significant differences between both types of retainers. The conventional 0.0215-in coaxial wire retainer was chosen as the most comfortable (p<0.05), although no statistically significant differences were found for all other questionnaire answers. Bonding failure events were more observed in the 3x3 V-Loop retainer (p<0.002), as compared to the conventional 0.0215-in coaxial retainer. CONCLUSION: V-Loop retainer showed higher PI (p<0.05), higher bonding failure rate and less comfortable, as compared to conventional 0.0215-in coaxial wire.

Orthodontic finishing errors detected in board-approved cases: common types and prediction.

OBJECTIVE: To report and rank orthodontic finishing errors recorded in the clinical phase of the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) examination and correlate pretreatment case complexity with orthodontic treatment outcomes. MATERIALS AND METHODS: This single-center cross-sectional survey collected retrospective data from the clinical phase of BBO examinations between 2016 and 2023. The quality of orthodontic clinical outcomes of each case was assessed by means of the Cast-Radiograph Evaluation (CRE), while case complexity was evaluated using the Discrepancy Index (DI), both tools provided by the American Board of Orthodontics. Survey items were analyzed using descriptive statistics, and a correlation analysis between total CRE and DI scores (p<0.05) was also performed. RESULTS: A total of 447 orthodontic records was included. Orthodontic finishing errors were often observed, and no case was completely perfect. In the total CRE score, an average of 15 points was discounted for each case. Most frequently found issues involved problems with alignment, buccolingual inclination, marginal ridge, and occlusal relationship. The median DI score for initial case complexity was 22.0 (range 10.0 - 67.0). There was no significant correlation between the DI and CRE scores (p=0.106). CONCLUSION: Orthodontic finishing errors are inevitable, even in well-finished board-approved cases. Rotation, excessive buccolingual inclination, and discrepancies in marginal ridges are the most frequently observed areas of concern, in that order. Moreover, while case complexity, determined by DI, can impact orthodontic planning and pose challenges for clinicians, the study did not consider it a determining factor in predicting treatment outcomes.

In vitro effect of two resin based materials for treating initial caries lesion around braces, under cariogenic challenge.

Background: Orthodontic treatment makes the patient susceptible to the development of white spot lesions (WSL) due to the greater accumulation of bacterial plaque. The purpose of this in-vitro study was to evaluate the preventive effect of two resin materials on the incidence of these lesions in the region adjacent to the fixed bracket bonded under a WSL-treated area by two resin materials. Material and Methods: 36 extracted human molars presenting natural WSL were included. They were randomly divided into 2 groups for intervention: IC (Infiltration resin Icon®) and PS (resin sealant Pro Seal ®). Braces were bonded just above the WSL. The enamel surface around the brace was treated by one of the tested materials, leaving another part to be control. The samples were submitted again to a cariogenic challenge. The exposed enamel non-treated area from booth groups comprised the control group (E). For morphological analysis, confocal images were taken at baseline, after treatment, and after pH cycling of each sample. Lesion depth were measured (µm) and compared to the enamel thickness to calculate a demineralization index. All groups were compared using the Kruskal Wallis test and Dunn's post-test. Results: PS group showed the lowest demineralization index (0.27 µm) when compared to the control area (0.39 µm) (p<0.05). IC presented a slightly higher percentage of lesions when compared to PS, however, did not differ significantly from the control exposed area. Conclusions: The resin sealant Pro Seal® had a positive protective effect under white spot environmental area and Icon® infiltrant, although showed some protection, did not statistically differ from controls. Key words:Dental Caries, Orthodontics, Dental Enamel, Sealants.

Accuracy of three-dimensional soft tissue profile prediction in orthognathic surgery.

PURPOSE: To evaluate the accuracy of three-dimensional (3D) soft tissue prediction in bimaxillary orthognathic surgery. METHODS: Cone-beam computed tomographs of 88 patients with class II (n = 46) and class III (n = 42) malocclusions, who underwent bimaxillary orthognathic surgery, were included in this retrospective study. 3D soft tissue prediction and postoperative outcome were compared by using ten landmarks of facial soft tissues. Patients' sex and age were also assessed. Results were analyzed using a mixed model methodology (p < 0.05). RESULTS: The success criterion adopted was a mean discrepancy of < 2 mm. Most mandibular landmarks indicated a tendency for underprediction with a downward direction in class II patients, with some values > 2 mm. In class III, there was overprediction with a downward direction for the mandibular landmarks, with values < 2 mm. More accurate results were found in female and older patients. CONCLUSIONS: 3D surgical planning showed clinically acceptable results for predicting soft tissues in patients undergoing bimaxillary orthognathic surgery, with more accurate results for class III patients. Although some differences were found when age and sex were interacted, a consistent association between these variables could not be stated. These results support the clinician, as accuracy can provide a strong guide to the surgeon when planning surgical orthodontic treatment.

Arthroscopy for temporomandibular disorders.

BACKGROUND: Temporomandibular disorders (TMDs) are considered a collection of disorders involving many organic, psychological and psychosocial factors. They can involve the masticatory muscles or the temporomandibular joint (TMJ) and associated structures, or both. It is estimated that 40% to 75% of the population displays at least one sign of the disease and 33% of the population reports at least one symptom. Arthroscopy has been used to reduce signs and symptoms of patients with TMD but the effectiveness has still not been totally explained. OBJECTIVES: To assess the effectiveness of arthroscopy for the management of signs and symptoms in patients with TMDs. SEARCH STRATEGY: The Cochrane Oral Health Group Trials Register (to 23 December 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2010), MEDLINE via OVID (1950 to 23 December 2010), EMBASE via OVID (1980 to 23 December 2010), LILACS via BIREME Virtual Health Library (1982 to 23 December 2010), Allied and Complementary Medicine Database (AMED) via OVID (1985 to 23 December 2010), CINAHL via EBSCO (1980 to 23 December 2010). There were no restrictions regarding the language or date of publication. SELECTION CRITERIA: Randomized controlled clinical trials of arthroscopy for treating TMDs were included. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, and three review authors independently assessed the risk of bias of included trials. The authors of the selected articles were contacted for additional information. MAIN RESULTS: Seven randomized controlled trials (n = 349) met the inclusion criteria. All studies were either at high or unclear risk of bias. The outcome pain was evaluated after 6 months in two studies. No statistically significant differences were found between the arthroscopy versus nonsurgical groups (standardized mean difference (SMD) = 0.004; 95% confidence interval (CI) -0.46 to 0.55, P = 0.81). Two studies, analyzed pain 12 months after surgery (arthroscopy and arthrocentesis) in 81 patients. No statistically significant differences were found (mean difference (MD) = 0.10; 95% CI -1.46 to 1.66, P = 0.90). Three studies analyzed the same outcome in patients who had been submitted to arthroscopic surgery or to open surgery and a statistically significant difference was found after 12 months (SMD = 0.45; 95% CI 0.01 to 0.89, P = 0.05) in favor of open surgery. The two studies compared the maximum interincisal opening in six different clinical outcomes (interincisal opening over 35 mm; maximum protrusion over 5 mm; click; crepitation; tenderness on palpation in the TMJ and the jaw muscles 12 months after arthroscopy and open surgery). The outcome measures did not present statistically significant differences (odds ratio (OR) = 1.00; 95% CI 0.45 to 2.21, P = 1.00). Two studies compared the maximum interincisal opening after 12 months of postsurgical follow-up. A statistically significant difference in favor of the arthroscopy group was observed (MD = 5.28; 95% CI 3.46 to 7.10, P < 0.0001). The two studies compared the mandibular function after 12 months of follow-up with 40 patients evaluated. The outcome measure was mandibular functionality (MFIQ). This difference was not statistically significant (MD = 1.58; 95% CI -0.78 to 3.94, P = 0.19).   AUTHORS' CONCLUSIONS: Both arthroscopy and nonsurgical treatments reduced pain after 6 months. When compared with arthroscopy, open surgery was more effective at reducing pain after 12 months. Nevertheless, there were no differences in mandibular functionality or in other outcomes in clinical evaluations. Arthroscopy led to greater improvement in maximum interincisal opening after 12 months than arthrocentesis; however, there was no difference in pain.

Interdisciplinary treatment for a patient with open-bite malocclusion and amelogenesis imperfecta.

Amelogenesis imperfecta (AI) comprises a clinically and genetically heterogeneous group of conditions that affect the dental enamel, occasionally in conjunction with other dental, oral, and extraoral tissues. The aim of this case report is to describe an interdisciplinary treatment of hypoplastic AI associated with a severe open bite. The treatment consisted of surgical, orthodontic, periodontal, prosthetic and restorative management, establishing good chewing function, dental esthetics and facial harmony.

Effect of teriparatide on induced tooth displacement in ovariectomized rats: a histomorphometric analysis.

INTRODUCTION: The aim of this study was to evaluate morphologically the effect of teriparatide on induced orthodontic movement of the maxillary first molars in ovariectomized rats. METHODS: Ovariectomized Wistar rats (n = 16), ovariectomized rats treated with teriparatide (n = 16), and nonovariectomized rats (n = 16) had orthodontic tooth movement for 5 and 7 days. The group treated with teriparatide received a subcutaneous injection (Forteo, Eli Lilly, Indianapolis, Ind; 30 µg/kg/day) for 90 days after the ovariectomy. Histologic sections obtained from the maxilla were prepared for the morphometric analysis of dental movement, the thickness of the periodontal ligament, and the number of osteoclasts in the pressure and tension areas of the apex of the root and alveolar crest in the distal root of the maxillary first molars. RESULTS: The ovariectomized rats treated with teriparatide had similar responses at 5 and 7 days after the induced dental movements compared with the untreated ovariectomized group. Both ovariectomized groups had greater molar movement on day 7 day compared with the controls (P <0.05). There were no statistically significant differences between groups in the spacing of the periodontal ligament or the number of osteoclasts in the areas studied. CONCLUSIONS: These data suggest that the treatment of osteoporosis with teriparatide is a good alternative for patients undergoing orthodontic treatment.

Impact of orthognathic surgery on the prevalence of dehiscence in Class II and Class III surgical-orthodontic patients.

OBJECTIVES: The objectives were to evaluate and compare the presence of bone dehiscence before and after orthognathic surgery. MATERIALS AND METHODS: In this retrospective study, 90 cone-beam computed tomography (CBCT) scans from 45 patients were evaluated. Class II (n = 23) and Class III (n = 22) orthodontic patients who were being prepared for orthognathic surgery were measured. CBCT scans were obtained about 30 days prior to (T0) and 6 months after (T1) double jaw orthognathic surgery. The distance between the cemento-enamel junction (CEJ) and the alveolar bone crest was assessed at the buccal and lingual surfaces of all teeth, on both sides and arches, except for the second premolars and the second and third molars. A total of 1332 sites were measured for Class II (644) and Class III (688) patients. The software used was OsiriX (version 3.3 32-bit). Data were compared with Wilcoxon and McNemar tests at the 5% level. RESULTS: Bone dehiscence before surgery was present in 26% and 15% of the Class II and III groups, respectively. The presence of dehiscence increased to 31% in the Class II and 20% in the Class III patients after surgery (P < .05). CONCLUSIONS: The prevalence of dehiscence increased slightly in Class II and Class III surgical-orthodontic patients after orthognathic surgery. Temporary vascular supply reduction and oral hygiene difficulties may explain these results; however, more studies are needed.

Bone dehiscence formation during orthodontic tooth movement through atrophic alveolar ridges.

OBJECTIVES: To test the null hypothesis that there is no difference in bone dehiscence formation before and after orthodontic tooth movement through an atrophic alveolar ridge. MATERIAL AND METHODS: This longitudinal retrospective study evaluated pretreatment and posttreatment cone-beam computed tomography imaging of 15 adult patients. Twenty-five teeth were moved through the atrophic alveolar bone, whereas 25 teeth not subjected to translational movement were considered controls. The distances between the cementoenamel junction and the alveolar bone crest were assessed at the mesial, distal, buccal, and lingual surfaces of all of these teeth. Data were compared using the Wilcoxon test. The Spearman correlation test and multivariate linear regression analysis were also performed. RESULTS: In general, crestal bone height was reduced around 0.5 mm in all groups in every direction. Median buccal dehiscence increased significantly (+2.25 mm) (P < .05) in teeth moved through the atrophic ridge. Control teeth also had buccal crest loss (+0.83 mm), but this was not statistically different from that of the experimental teeth. Lingual dehiscence increased significantly for the experimental (+0.17 mm) and control (+0.65 mm) groups. Mesial bone height decreased more in the control group (-0.44mm) than in the experimental group (-0.14mm). There was moderate correlation between amount of tooth movement and alveolar bone loss. CONCLUSIONS: The null hypothesis was rejected as dehiscence increased after tooth movement through an atrophic alveolar ridge, mainly in the buccal plate.

Lateral and apical root resorption in teeth orthodontically moved into edentulous ridge areas.

OBJECTIVE: The present study aimed at comparing the external lateral root resorption (ELRR) and external apical root resorption (EARR) between teeth moved through the atrophic edentulous ridge and those undergoing the usual orthodontic movement. METHODS: Fifty-four premolars were evaluated, where 27 of them had been moved toward the edentulous ridge (Group 1) and 27 from the same patient, had not been translated, which comprised the control group (Group 2). ELRR was evaluated by 0-3 scores and EARR was evaluated by 0-4 scores, before and after movement. Measurements were compared by Kruskal-Wallis and Student-Newman-Keuls tests. RESULTS: ELRR increased statistically only in the Group 1 (p< 0.05). After orthodontic treatment, it was observed that almost 56% (n = 15) of teeth in Group 1 presented scores 2 and 3, while Group 2 presented scores 2 and 3 in about 11% (n= 3) of the teeth. EARR increased in both groups after orthodontic movement, however, statistically analyses showed no significant differences between groups (p> 0.05). CONCLUSIONS: Orthodontic movement into the atrophic edentulous ridge is subject to a greater lateral external root resorption.

DSC analysis and evaluation of forces released on deactivation of 0.40-mm (0.016") orthodontic thermo-activated NiTi wires: An in vitro study.

Background. This study evaluated the phase transformation of NiTi orthodontic wires and forces they release on deactivation. Methods. The structural phase transformations of the following five thermo-activated nickel-titanium (NiTi) wires were evaluated using differential scanning calorimetry (DSC): Flexy Thermal Sentalloy® (GAC International), NiTi (35ºC) (Eurodonto), Thermo-Plus® (Morelli), FlexyNiTi® Flexy Thermal (35ºC) (Orthometric) and Damon® CuNiTi (35ºC) (ORMCO Corp.). The wires had a cross-section of 0.40 mm (0.016"). In addition, the forces they released were investigated using the three-point bending test. Five arches of each wire were tested using DSC (-20/80ºC at 10ºC/min), and six arches from each wire were sectioned for bending tests. The data were analyzed with ANOVA and post hoc Tukey tests. Pearson's correlation test was performed between the results yielded by the DSC tests and those by three-point analyses (P=0.05). Results. The DSC analysis showed differences between the NiTi alloys from all the manufacturers, with no differences between the lots of the same brand. ORMCO and Orthometric wires exhibited similar TTR values in cooling (P=0.49), and statistically similar TTR values in heating (P=0.056). The three-point bending test showed different patterns in releasing forces. A correlation was found between the DSC analysis and the three-point bending test results. Conclusion. The higher the temperature transformation was, the larger was the variation of force. All the wires presented higher forces at 3-mm deflection from 155 (±12.3) to 168.1 (±8) cN. The DSC analysis and the three-point bending test showed differences between the NiTi alloys from all the manufacturers.

How does bimaxillary orthognathic surgery change dimensions of maxillary sinuses and pharyngeal airway space?

OBJECTIVES: To assess changes in the maxillary sinus (MS) and pharyngeal airway space (PAS) after bimaxillary orthognathic surgery using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The CBCT scans of 48 patients were divided into two groups: group 1: maxillary advancement and mandibular setback (n = 24); group 2: maxillomandibular advancement (n = 24). The CBCTs were acquired 1 to 2 months preoperatively and 6 to 8 months postoperatively. A kappa test was used to determine intra- and interexaminer agreement. Area, volume, and linear measurements of MSs and PASs obtained before and after surgery were compared using a mixed model (P < .05). RESULTS: All variables of the MS showed significant postsurgical reductions in both groups, except the MS length, which showed a significant increase in group 2. Volume and minimum axial area of PAS showed statistically significant postsurgical increases in both groups (P < .05). CONCLUSIONS: Despite the reduction in the MS and the increase in the PAS, results indicated that the airway was not negatively affected after maxillomandibular advancement and maxillary advancement with mandibular setback.

Efficacy of fluoride associated with nano-hydroxyapatite in reducing enamel demineralization adjacent to orthodontic brackets: in situ study.

OBJECTIVE: To assess in situ the effect of fluoride associated with nano-hydroxyapatite for the prevention of demineralization of the enamel adjacent to orthodontic brackets. MATERIAL AND METHODS: Eight volunteers wore palatal devices prepared with 6 bovine enamel blocks (5x5x2 mm) with bonded brackets. The volunteers used the devices in two different moments of 14 days each. During the first 14 days, a product containing fluoride + nano-hydroxyapatite was applied twice (experimental group, GNH, n = 48), and for the other 14 days no prevention product was applied (control group, CG, n = 48). In both groups, along the experiment, the blocks were dripped with 20% sucrose eight times daily. After the experiment, all the specimens were sectioned and examined for lesion depth analysis (µm) under polarized light microscopy, and for enamel longitudinal microhardness (measured under the bracket, at 30 µm and at 130 µm from the margin), at seven different depths (10, 20, 30, 50, 70, 90, and 110 µm). RESULTS: Under polarized light, group GNH presented significantly less demineralization depth ( X ¯ = 15.01 µm, SD = 33.65) in relation to CG ( X ¯ = 76.43 µm, SD = 83.75). Enamel longitudinal microhardness demonstrated significantly higher microhardness for group GNH when compared to CG. CONCLUSION: Fluoride + nano-hydroxyapatite can be an alternative preventive procedure for demineralization of the enamel adjacent to orthodontic brackets.

Three-dimensional alterations in pharyngeal airspace, soft palate, and hyoid bone of class II and class III patients submitted to bimaxillary orthognathic surgery: A retrospective study.

INTRODUCTION: The aim of this retrospective study was to evaluate changes in pharyngeal airway space (PAS), soft palate, and hyoid bone position after bimaxillary orthognathic surgery in skeletal Class II and Class III patients. METHODS: Patients were divided into Group 1: Class III patients who underwent maxillary osteotomies and mandibular setback surgery (N = 43); and Group 2: Class II patients who underwent maxillomandibular advancement surgery (N = 36). Cone beam computed tomography (CBCT) images were acquired one month before and six to eight months after orthognathic surgery. PAS area, volume and minimum axial area (MAA), soft-palate morphology, and hyoid bone position measurements obtained before and after orthognathic surgery were compared using the Gamma family test (p ≤ 0.10). RESULTS: In Class II group the maxillomandibular advancement surgery significantly increased the PAS area, volume, and MAA and significantly affected hyoid bone position and soft-palate morphology. In Class III group, maxillary osteotomies and mandibular setback also showed increase in PAS area, however without statistically significant values for most of the evaluated measurements. CONCLUSION: The results of the present study indicate that PAS and related structures are expected to be improved in Class II patients submitted to bimaxillary surgery, and they are not negatively affected by bimaxillary surgery in Class III patients.

Periodontal indexes of two types of 3 x 3 retainers: 0.032-in SS V-loop versus 0.0215-in SS coaxial - a randomized crossover trial

ABSTRACT Objective: This randomized crossover trial evaluated periodontal indexes of two types of 3 x 3 retainers (a modified 0.032-in SS V-loop retainer and a conventional 0.0215-in SS coaxial wire retainer) after bonded for six months. Also, bonded failure rate, and a questionnaire about comfort, ease of cleaning and overall preference were recorded. Material and Methods: 15 patients were enrolled in this study who used both retainers for six months each, having a 15-day wash-out interval between each bonded retainer usage. The following periodontal index were recorded: Plaque Index (PI), Calculus Index (CI) and Gingival Index (GI). Patients answered a questionnaire to assess comfort, ease of cleaning and overall retainer-type preference. Rate of bonding failure was also evaluated. Results: V-Loop retainer showed higher PI (P<0.05) as compared to conventional 0.0215-in coaxial wire retainer. However, CI and GI presented no statistically significant differences between both types of retainers. The conventional 0.0215-in coaxial wire retainer was chosen as the most comfortable (p<0.05), although no statistically significant differences were found for all other questionnaire answers. Bonding failure events were more observed in the 3x3 V-Loop retainer (p<0.002), as compared to the conventional 0.0215-in coaxial retainer. Conclusion: V-Loop retainer showed higher PI (p<0.05), higher bonding failure rate and less comfortable, as compared to conventional 0.0215-in coaxial wire.

RESUMO Objetivo: Este estudo cruzado e randomizado avaliou os índices periodontais de dois tipos de contenções 3x3 (uma contenção aço V-Loop de 0,032" modificada e uma contenção convencional de fio coaxial aço de 0,0215") após colagem, por seis meses. Além disso, foram registradas a taxa de falha na colagem e um questionário sobre conforto, facilidade de limpeza e preferência geral. Material e Métodos: Foram incluídos nesse estudo 15 pacientes que usaram ambas as contenções por seis meses cada, com intervalo de quinze dias entre cada contenção fixa. Foram registrados os seguintes índices periodontais: Índice de Placa (IP), Índice de Cálculo (IC) e Índice Gengival (IG). Os pacientes responderam a um questionário para avaliar o conforto, a facilidade de limpeza e a preferência geral pelo tipo de contenção. A taxa de falha de colagem também foi avaliada. Resultados: A contenção V-Loop apresentou maior IP (p<0,05) em comparação ao fio coaxial convencional. Entretanto, IC e IG não apresentaram diferenças estatisticamente significativas entre as contenções testadas. A contenção convencional de fio coaxial 0,0215" foi escolhida como a mais confortável (p<0,05), embora não tenham sido encontradas diferenças estatisticamente significativas para todas as outras respostas do questionário. Eventos de falha de colagem foram mais observados na contenção V-Loop 3 x 3 (p<0,002) em comparação com a contenção coaxial convencional de 0,0215". Conclusão: A contenção V-Loop apresentou maior IP (p<0,05), maior taxa de falha de colagem e foi menos confortável em comparação ao fio coaxial convencional 0,0215".

Orthodontic root resorption of endodontically treated teeth.

The purpose of this study was to evaluate, radiographically, whether there is similarity in the apical root resorption found in endodontically treated teeth and untreated teeth when they are submitted to orthodontic treatment. From 2,500 treatment records examined, 16 patients were selected who had a maxillary central incisor treated endodontically before initiation of the orthodontic movement, and a vital homologous tooth (for control). Measurements were made by comparing the periapical radiographs taken before and after the orthodontic treatment. There was no statistically significant difference (p>0.05) in apical root resorption found in the endodontically treated teeth compared to the group of vital teeth.

Three-dimensional analysis of the pharyngeal airway space and hyoid bone position after orthognathic surgery.

PURPOSE: The aim of this study was to evaluate changes in the pharyngeal airway space (PAS) and hyoid bone position after orthognathic surgery with cone-beam computed tomography (CBCT). MATERIAL AND METHODS: This study was conducted with the tomographic records of 30 patients with skeletal class II or III deformities submitted to two different types of orthognathic surgery: Group 1 (n = 15), maxillary advancement, and mandibular setback; and Group 2 (n = 15), maxillomandibular advancement. CBCT scans were acquired preoperatively (T0); and at around 1.5 months (T1) and 6.7 months (T2) postoperatively. PAS volume, minimum cross-sectional area (min CSA), and hyoid bone position changes were assessed with Dolphin Imaging 3D software, and results analyzed with ANOVA and a Tukey-Kramer test (p < 0.05). RESULTS: The hyoid bone was significantly displaced in the horizontal dimension, moving posteriorly in Group 1, and anteriorly in Group 2. Although PAS volume and min CSA increased after both surgeries, these measurements were significantly larger only in Group 2. The significant differences that existed between groups preoperatively no longer existed after the surgeries. CONCLUSIONS: Both orthognathic surgeries assessed resulted in changes in hyoid bone position and increased PAS volume and min CSA, particularly after maxillomandibular advancement surgery.