Three-dimensional assessment of the maxilla after modified surgically assisted rapid expansion: a retrospective study.

OBJECTIVE: This retrospective study aims to assess the three-dimensional dentoskeletal effects and median palatal suture opening pattern in patients undergoing modified surgically assisted maxillary rapid expansion (SARME) without pterygoid plate detachment. METHODS: Twenty-eight patients submitted to modified SARME between 2009 and 2016 were retrospectively evaluated through cone-beam computed tomography (CBCT). Dental and skeletal measurements were taken at three different operative periods (before the expansion - T0; at the end of the activation of the Hyrax device - T1; and six months after the immobilization of the device - T2). Statistical analyses, including ANOVA and Pearson's correlation coefficient, were performed using SPSS software. RESULTS: SARME demonstrated significant transverse maxillary expansion (with an average of 6.05 mm) with a greater impact in the anterior region. Dental measurements, including canine and molar distances, exhibited significant changes over the operative periods. Bone measurements (ANS and PNS) presented small but significant alterations, including a slight inferior displacement of ANS during device activation. The nasal floor width increased, followed by a width reduction after immobilization. The median palatal suture predominantly exhibited a Type II (V-shaped) opening. CONCLUSION: The modified SARME presented a transversal direction increase and a super-lower skeletal displacement, with the anterior region being more affected than the posterior region. There was no change in the anteroposterior direction of the maxilla. Additionally, there was an increase in the linear dental measurements and a decrease in the angular measurement, with a positive correlation between the amount of posterior bone expansion and molar expansion as a result of the treatment in the analyzed period.

Epidemiological Study of Frontal Sinus Fractures: Evaluation of 16 Years of Care at the Faculty of Dentistry of Ribeirão Preto/Brazil.

Purpose: Aiming to evaluate and study the epidemiological profile of frontal sinus fractures treated in the region of Ribeirão Preto-Brazil. Methods: Sixteen years of activity in the Oral and Maxillofacial service of the Faculty of Dentistry of Ribeirão Preto/SP (FORP/USP), totaling 9,736 consultations, 4,524 with facial fractures, those diagnosed with frontal sinus fracture (113) were evaluated and selected for the study. Results: Frontal sinus fractures accounted for 2.5% of facial fractures, the majority occurring in men (89.4%), concentrated in the age group 21-30 years old, with 52.2% of cases being caused by road traffic accidents (RTA). Associations with other facial fractures are common and appeared in 75.2% of cases. Treatment was followed either surgically, by open reduction internal fixation (52.2%) or conservatively (35.4%). Analyzing only the 28 isolated frontal sinus fractures, the most common treatment was conservative (46.4%). surgical treatment dropped to 25%. The most common postoperative complications were temporal branch paralysis and supraorbital nerve paresthesia, both occurring in 30.5% of surgical cases. Conclusion: The frequency of frontal sinus fractures may be decreasing, but the pattern of occurrence in young men due to road traffic accidents does not seem to change, fortunately the appearance of serious complications is not common and it is usually associated with more severe trauma.

Pseudocarcinomatous Squamous Hyperplasia After Surgical Management Of Pediatric Ameloblastoma: An Immunohistochemical Study.

Pseudocarcinomatous squamous hyperplasia (PSH) affecting the jaws is uncommon. The mandible is the most common location, usually as a complication associated with osteomyelitis, medication-related osteonecrosis or osteoradionecrosis. Herein, we report an 8-year-old male patient presenting a solid ameloblastoma, plexiform type, who was treated by segmental mandibulectomy with bone grafting. Three months later, on the underlying graft, a sinus tract was observed, and a small bone fragment was resected which was diagnosed as bone sequestration associated with PSH. After 7-year follow-up, the patient is well, without alterations. To our knowledge, for the first time, we report in detail the immunohistochemical features of PSH which, in addition to epithelial component profile and chronic inflammatory cells, revealed a diffuse infiltration by dendritic cells, suggesting that epithelial cell-immune cell interactions in PSH pathogenesis should also be considered.

Retrospective analysis of the predictability of using three-dimensional models for preoperative planning of the length of zygomatic implants.

PURPOSE: This present study aimed to retrospectively evaluate the predictability of using three-dimensional models (TDMs) to plan the preoperative lengths of zygomatic implants (ZIs). METHODS: The records of all patients that received such implants between March 2007 and March 2019 were evaluated. The ZI lengths predicted on the TDMs were compared to the lengths of the implants the patients received. RESULTS: In total, the records of 74 patients were evaluated, of which 37 records met the criteria of inclusion, and were included in the study. Twenty-seven (73%) of the patients were female and 10 (27%) were male, ranging from 34 to 80 years of age, with the average age being 55.7 years. Seventeen (43.2%) of these patients were classified as ASA I and 21 (56.8%) as ASA II. A total of 142 ZIs were planned and installed in the time frame mentioned. Without distinguishing the region of the maxilla, the implants used were, on average, 1.1 mm larger in length than those initially planned. CONCLUSION: Overall, the data indicates moderate agreement between the planned and surgical lengths of the ZIs and indicates that using TDMs is a predictable and reliable preoperative planning technique of the length of posterior ZIs.

Laboratorial Comparative Study of the Accuracy Between Virtual Planning and Erickson's Platform.

Purpose: The goal was to perform an orthognathic surgery laboratorial study to evaluate the reproducibility of the resulting movements from virtual surgical planning (VSP), by comparing the measurements obtained from VSP to those obtained from Erickson's platform using the 3D printed surgical guide. Methods: Eight patients who had undergone orthognathic surgery were screened and grouped according to maxillary movement and the patient's dentofacial deformity. Three-D virtual surgery simulations were performed, and surgical guides were obtained using Dolphin Imaging 11.9® software. In a semi-adjustable articulator (SAA), the maxilla model was separated from the SAA mounting platform, and the surgical guide was used to reassemble it. Then, the maxilla model was fixed and transferred to Erickson's platform to verify the planned movement. The data were submitted for statistical analysis. Results: The agreement between the methods was excellent, regardless of direction, landmark analyzed, or the amount of movement. The most considerable variation was 0.42 mm in the movement amplitude of 6 mm, and the highest mean was 0.07 mm in the region of the superior right first molar (16). Conclusion: Therefore, regardless the movement of the maxilla, no statistically significant difference was observed between the measurements obtained through VSP and Erickson's platform, demonstrating that both methods are equally accurate and reliable.

Reproducibility of a three-dimensional skeletal-based craniofacial orientation method for virtual surgical planning.

Inadequate craniofacial orientation of computed tomography (CT) scans can have significant implications in all three planes of space. The purpose of this study was to present the reproducibility of a 3-dimensional skeletal-based method of craniofacial orientation for virtual surgical planning. The protocol was defined by landmarks commonly used for cephalometry, and required identification of basion, nasion, right porion, and right orbitale, and navigation in all CT views (coronal, sagittal, and axial) for correction of yaw, roll, and pitch. Reproducibility of the method was assessed using eight CT scans that were randomly selected and anonymised. The observer group consisted of six oral and maxillofacial surgeons with varying levels of experience (resident or faculty) who performed craniofacial orientation according to the proposed method. Results were expected to be below 2° of variation, when overall accuracy as well as the influence of the academic level of the observers and symmetry of the evaluated anatomy, were considered as independent variables. Overall accuracy for all cases and for yaw, roll, and pitch were always below 2° of variation, without influence of level of experience and symmetry. Interobserver assessment was categorised as excellent in all instances, and intraobserver evaluation demonstrated consistency in the orientation of all axes. The proposed craniofacial orientation protocol presented in this study is easy to learn, applicable to computer-aided surgical planning, and can be performed by the non-technical clinician, resulting in excellent reproducibility and consistency.

Does the type of sagittal split ramus osteotomy influence fixation strength? Evaluation of the mechanical behavior of two types of fixation used in three types of sagittal split ramus osteotomy.

PURPOSE: This study compared the mechanical behavior of two fixation techniques used in three sections representing the sagittal split ramus osteotomy (SSRO) in polyurethane replicas that were divided into groups, according to type of section, and sub-groups according to type of fixation, simulating 11-mm advancement and 6º clockwise mandibular rotation. METHODS: Loads were applied in two regions, aiming at progressive application and consequent strength value, measured in kilogram-force in displacements of 1, 3, 5, and 7 mm, from the load application tip. Shapiro-Wilk test was performed, followed by two-way analysis of variance (ANOVA-2 way), and Bonferroni's multiple comparison. RESULTS: The results showed no statistically significant difference in the type of section and type of fixation used when load was applied to the inter-incisor region. However, when load was applied to the first molar region, statistically significant difference was observed in 1-mm displacement, in which section described by Epker with two modifications showed greater strength, regardless of type of fixation used (p = 0.007). CONCLUSION: In the application of load in the inter-incisor region, there was no statistical difference between the type of osteotomy and the type of fixation used. When applying loads to molars, there was a difference for the type of osteotomy, where the Epker osteotomy with 2 modifications presented greater resistance, regardless of the type of fixation used.

Surgically assisted rapid palatal expansion (SARPE): three-dimensional superimposition on cranial base.

OBJECTIVES: To evaluate dental and skeletal changes caused by surgically assisted rapid palatal expansion (SARPE) using the superimposition of three-dimensional cone-beam computed tomography (CBCT) images on the cranial base. MATERIAL AND METHODS: This is a retrospective quasi-experiment before-and-after study using a convenience sample. Twenty-four adult patients (13 male and 11 female) were evaluated before SARPE (T0), immediately after expansion (T1), and after 6 months of retention (T2). CBCT scans were superimposed on the anterior cranial base using voxel-based registration. Measurements from different reference points were used for comparisons between times. RESULTS: At T1, all teeth had significant buccal tipping. At T2, most teeth remained in the same position as at T1, except the first premolar and the first molar, whose buccal roots moved slightly. The amount of bony expansion was 65 to 70% of the amount of tooth movement. The A point and maxillary incisors moved anteriorly from T0 to T1 and T2 (p < 0.0001). Inter-nasal distance had increased significantly at T1 (p < 0.0001) and remained stable at T2 (p = 0.478). No expansion was achieved at the zygomatic arch (p = 0.114). CONCLUSION: SARPE promoted substantial buccal tipping of posterior teeth and some bone displacement; it also moved the maxilla and teeth forward and increased nasal width. CLINICAL RELEVANCE: No other clinical studies have evaluated dental and skeletal changes caused by SARPE using superimposition of 3D CBCT images on the cranial base. This study findings may help clinical dentists plan treatments using safe and reliable information.

Effect of vomer position following surgically assisted rapid palatal expansion.

PURPOSE: To evaluate the effect of vomer position and prevalence of periodontal dehiscence in patients who underwent surgically assisted rapid palatal expansion (SARPE). The null hypotheses were the following: (1) vomer position in the coronal plane does not influence the degree of skeletal and dental expansion; and (2) there is no association between expansion, periodontal dehiscence and vomer position. METHODS: Twenty-one patients were evaluated before treatment (T0) and immediately after SARPE expansion (T1). After SARPE, the vomer was in the right side in 11 patients and in the left in 10 patients. Skeletal and dental effects were evaluated using CBCT, landmarks and measurements. RESULTS: The maxilla and the nasal cavity expanded asymmetrically. The side containing the vomer had less skeletal expansion but more dental tipping. Dehiscence increased significantly from T0 to T1 and was associated with the amount of skeletal displacement, especially when greater than 3.20 mm. In the first premolars region, there was more than 2 mm of asymmetric expansion observed in 38.5% of the patients. CONCLUSION: The null hypotheses were rejected. The side containing the vomer had less skeletal expansion of the maxilla and nasal cavity but more dental tipping. Dehiscence increased after expansion, but there were no differences between sides.