Automated 3-D Computer-Aided Measurement of the Bony Orbit: Evaluation of Correlations among Volume, Depth, and Surface Area.

(1)The study aimed to measure the depth, volume, and surface area of the intact human orbit by applying an automated method of CT segmentation and to evaluate correlations among depth, volume, and surface area. Additionally, the relative increases in volume and surface area in proportion to the diagonal of the orbit were assessed. (2) CT data from 174 patients were analyzed. A ball-shaped mesh consisting of tetrahedral elements was inserted inside orbits until it encountered the bony boundaries. Orbital volume, area depth, and their correlations were measured. For the validation, an ICC was used. (3) The differences between genders were significant (p < 10-7) but there were no differences between sides. When comparing orbit from larger to smaller, a paired sample t-test indicated a significant difference in groups (p < 10-10). A simple linear model (Volume~1 + Gender + Depth + Gender:Depth) revealed that only depth had a significant effect on volume (p < 10-19). The ICCs were 1.0. (4) Orbital volume, depth, and surface area measurements based on an automated CT segmentation algorithm demonstrated high repeatability and reliability. Male orbits were always larger on average by 14%. There were no differences between the sides. The volume and surface area ratio did not differ between genders and was approximately 0.75.

Influence of preoperative anatomy and functional status on outcomes after total temporomandibular joint replacement with patient-specific endoprostheses: A retrospective cohort study.

BACKGROUND: Temporomandibular joint (TMJ) replacement may be indicated for various pathological conditions, and the type of condition can affect the surgical procedure and outcomes. The causes of limited range of motion after alloplastic TMJ replacement have not been extensively studied. OBJECTIVES: The present study aimed to evaluate the impact of preoperative jaw anatomy and functional status on the immediate and long-term outcomes of total TMJ replacement using a two-component patient-specific TMJ endoprosthesis. MATERIAL AND METHODS: This retrospective study included 31 patients who underwent total TMJ replacement surgery between 2016 and 2020. The main outcome variable was the maximal incisal opening (MIO) after treatment. Secondary outcome variables included MIO improvement and the presence and type of postoperative complications. The primary predictive variable was the preoperative initial MIO. Secondary predictive variables included sex, age, indications for TMJ replacement, preoperative occlusion, condition of the glenoid fossa and/or condyle, shortening of the mandibular ramus, sagittal mandible position, lateral chin deviation, shape of the coronoid process, and type of surgery. RESULTS: The mean preoperative MIO was 13.0 ±8.0 mm, while the mean MIO 1 month after surgery was 20.6 ±5.5 mm, which was not statistically significant. However, at a later follow-up, functional parameters showed a significant improvement (p = 0.003), with a mean MIO of 32.5 ±5.0 mm 3 years after surgery. Statistical analysis indicated that the initial mouth opening is the strongest predictor of long-term functional recovery after TMJ replacement. Postoperative complications occurred in 4 cases (12.9%) following patient-specific endoprosthesis (PSE) placement. CONCLUSIONS: The use of PSEs for TMJ replacement has enabled the restoration of anatomical relationships in complex clinical cases and an improvement in mouth opening. The preoperative MIO was the only factor that significantly influenced long-term functional outcomes.

Delayed reconstruction of the combat-related mandibular defects with non-vascularized iliac crest grafts: Defining the optimal conditions for a positive outcome in the retrospective study.

BACKGROUND: Reconstruction of mandibular defects caused by combat injuries is challenging for clinicians due to soft tissue defects and high complication risk. This study evaluated the outcomes of mandibular continuous defects reconstruction with non-vascularized iliac crest graft (NVICG) in patients with combat injuries. MATERIAL AND METHODS: Patients with continuous mandibular defects acquired by high-velocity agents, who received NVICG reconstruction with or without microvascular-free soft tissue or regional flaps, were included in the study. The outcome variable was graft loss due to postoperative complications or full (more than 90 %) resorption. The primary predictor variable was soft tissue defect in the recipient area. The secondary predictor variable was the length of the defect. Variables related to patients, defect site, surgery, and other complications were also evaluated. Statistical analysis was performed with the usage of independent sample t-test, Pearson's chi-squared and Fisher's exact tests with a significance level of P < 0.05 RESULTS: The study included 24 patients with 27 mandibular defects. Overall, the general success rate of reconstructions was 59.3 %. Soft tissue defects were significantly associated with graft failure and other complications (p < 0.05), which were mostly related to soft tissue defects. The graft success rate was only 14.3 % even in minor soft tissue defects. In turn, in reconstructions with sufficient soft tissue coverage, the graft survived in 75.0 % of the cases. In addition, patients with more delayed reconstruction had significantly fewer graft failures than those with earlier surgery (p < 0.05). No associations were found between defect size and complications. CONCLUSION: The sufficient soft tissue coverage is essential in the reconstruction of mandibular defects caused by combat injuries. Also, minor soft tissue defects should be covered with soft tissue flaps to avoid complications and graft loss in these specific injuries. Even large defects can be reconstructed with NIVICG if the soft tissue coverage is sufficient.

Clinical manifestations of I-131 induced salivary gland dysfunction in patients with thyroid carcinoma

Aim: To carry out a retrospective analysis of the frequency and severity of clinical signs of radioiodine (131I)-induced damage to the salivary glands in the early and long-term post-radiation periods, and identify risk factors for their occurrence in patients with differentiated thyroid carcinomas. Methods: A total of 330 patients underwent thyroidectomy with dissection of lymphatic nodes. One month after surgery, all the patients received radioiodine therapy. The dose and number of courses varied depending on the stage and morphological type of the tumor. In the late post-radiation period, the patients were surveyed with the use of a standard questionnaire, which allowed retrospective assessment of the nature and severity of symptoms of radiationinduced damage, as well as the time of their onset/subsidence. Results: Radiation-induced sialoadenitis of the salivary glands was observed in 51.2% of patients treated with 131I. The main symptoms included pain and discomfort in the salivary glands (51.2% of patients), swelling (48.8%), transient or permanent dry mouth (38%), and distortion of taste (38%). There were statistically significant correlations between the presence and severity of the main clinical symptoms of salivary gland irradiation. A significant relationship (r = 0.91, p < 0.001) was found between swelling of the salivary glands and the feeling of pain or discomfort, which was indicative of inflammation and retention of saliva. Conclusion: The main factors influencing the formation of chronic radiation-induced sialoadenitis and the severity of the inflammatory process included the tumor stage, the total dose of radiopharmaceuticals, and the duration following radioiodine therapy

STUDY OF THE STRESS-STRAIN STATE OF THE MAXILLA DURING ORTHODONTIC TREATMENT OF DENTOGNATHIC DEFORMATIONS IN CHILDREN WITH CONGENITAL CLEFT LIP AND PALATE.

OBJECTIVE: The aim: To create a three-dimensional simulation mechanical-mathematical model of the biomechanical system "Orthodontic appliance-maxilla", to study peculiarities of the stress-strained state of the maxilla. PATIENTS AND METHODS: Materials and methods: A simulation model of the biomechanical system "Orthodontic appliance-maxilla" was created using computed tomography (CBCT) data. Mathematical modeling was used to determine the stress-strain state of the simulation model. RESULTS: Results: The patterns of changes in the stress state were determined and the values of deformation displacements in the structural elements of the biome-chanical system "Orthodontic appliance-maxilla" were determined under a force stress of the orthodontic device with an amplitude of 50 N. CONCLUSION: Conclusions: Simulation computer modeling of the stress-strain state of the "Orthodontic appliance-maxilla" system showed that activation of the kinematic mechanism of the appliance with a force of 50 N causes the emergence of a complex stress-strain state of bones. When the orthodontic appliance is activated, there is an asymmetry in the distribution of stresses by Mises between the right and left sides both for the appliance itself and for the maxillary bone tissue.

Condiciones de aplicación del injerto ilíaco óseo en la sustitución de defectos mandibulares: un estudio retrospectivo de 11 años de experiencia / Conditions of iliac bone grafts application in mandibular defects replacement: a retrospective study of 11-years’ experience

Antecedentes: Este estudio tenía como objetivo aclarar la aparición y las causas de complicaciones postoperatorias en pacientes con defectos mandibulares continuos, reconstruidos con injertos óseos ilíacos libres. Pacientes y métodos: Los pacientes con defecto de continuidad mandibular con pérdida de tejido óseo, que dio lugar a una brecha de 2 cm o más, se sometieron a reconstrucción con injerto óseo de cresta ilíaca no vascularizado. La variable de resultado fue el fracaso del injerto, que se definió como su pérdida por infección postoperatoria, exposición del injerto, reabsorción completa o no unión del injerto. Los factores predictivos fueron el momento de la reconstrucción, la longitud del defecto óseo, la presencia preoperatoria de defecto mucoso y/o dehiscencia y el método de fijación. Todas las variables explicativas y predictoras se analizaron mediante regresión logística binomial univariante.Resultados: El estudio incluyó los resultados de 50 reconstrucciones mandibulares con injerto óseo de cresta ilíaca no vascularizado que se observaron retrospectivamente. El seguimiento de los pacientes incluidos osciló entre 6 meses y 11 años. 34 pacientes (68 %) tuvieron resultados quirúrgicos satisfactorios. En 16 pacientes (32 %) se perdieron los injertos óseos. Todos ellos debido al desarrollo de infección, supuración y/o exposición del injerto durante los primeros 6 meses del periodo de observación. En el análisis univariante, las principales variables predictoras de fracaso fueron el tabaquismo (OR 5,8; IC: 1,48-22,7; p = 0,002), el momento de la reconstrucción (OR 7,94; IC: 1,88-33,5; p = 0,004) y el defecto o dehiscencia de la mucosa (OR 8,49; IC: 2,21-32,6; p = 0,002). El análisis multivariante también reveló la afectación sinfisaria del defecto (OR 5,63; IC: 1,14-27,8; p = 0,034) como factor predictivo significativo de fracaso en un caso de reconstrucción inmediata. ... (AU)

Background: This study aimed to clarify the occurrence and causes of postoperative complications in patients with continuous mandibular defects, reconstructed with free iliac bone grafts.Patients and methods: Patients with mandibular continuity defect with bone tissue loss, resulting in a 2 cm gap or more underwent reconstruction with non-vascularized iliac crest bone graft. The outcome variable was graft failure which was defined as its loss due to the postoperative infection, graft exposure, full resorption or non-unition of the graft. The predictors were timing of reconstruction, length of the bone defect, preoperative presence of mucosa defect and/or dehiscence and fixation method. All explanatory and predictor variables were analyzed with univariate binomial logistic regression.Results: The study included the results of 50 mandibular reconstructions with non-vascularized iliac crest bone graft which were observed retrospectively. The follow-up of included patients ranged from 6 months to 11 years. 34 patients (68 %) had successful surgery results. In 16 patients (32 %) the bone grafts were lost. All of them due to the infection development, suppuration and/or graft exposure during the first 6-months of the observation period. In univariate analysis, the main failure predictor variables were smoking (OR 5.8, CI 1.48-22.7, p = 0.002), timing of reconstruction (OR 7.94, CI 1.88-33.5, p = 0.004) and mucosa defect or dehiscence (OR 8.49, CI 2.21-32.6, p = 0.002). The multivariate analysis also revealed symphyseal involvement of defect (OR 5.63, CI 1.14-27.8, p = 0.034) as the significant failure predictor in a case of immediate reconstruction. The length of defect and fixators type remained statistically non-significant for mandibular reconstruction with NVICG (p < 0.05).Conclusion: ... (AU)

Recurrent Ameloblastoma: Clinical Manifestation and Disease-Free Survival Rate.

Objectives: Ameloblastoma is a slow-growing epithelial odontogenic neoplasm of the jaws with a high recurrence rate. The main treatment strategies for this lesion are radical or conservative surgical approaches. The aim of the present study was to analyze clinical presentations, histological types, and treatment strategies of recurrent ameloblastoma and to define its disease-free survival (DFS) rate. Materials and Methods: Twenty-four cases of recurrent ameloblastomas, treated between January 2009 and July 2021, were enrolled in this study. Medical files from each patient, including gender, age, size of the lesion, localization, patient complaints, clinical manifestation, radiographic appearance, histological type, surgical management, and treatment results were reviewed and analyzed retrospectively. Result: Out of 69 operated primary ameloblastomas, the rate of recurrence was 35%. Out of 24 recurrent cases, 21 developed after conservative treatment and 3 after radical treatment. In most cases, recurrences were found in the mandible (n = 20). A unilocular pattern was predominant in radiographic examination (44%). Estimated 3-year DFS was 84.5 ± 4.8%, and the 5-year and 10-year DFS were 73.0 ± 6.3% and 43.9 ± 8.343.9 ± 8.3%, respectively. Conclusion: Results obtained in the present retrospective study proved the necessity of long-term follow-up after both conservative and radical treatment approaches. The DFS median in our study was 8 years (95% CI 6 years-10 years). For recurrent cases, radical resection with histologically free margins after exact MRI determination of the ameloblastoma border within the soft tissues should be considered as the method of choice to avoid secondary recurrence.

The epidemiology and management of ameloblastomas: A European multicenter study.

The present study aimed at assessing the epidemiology including demographic variables, diagnostic features, and management of ameloblastomas at several European departments of maxillofacial and oral surgery. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, type, histopathological features, kind of treatment, length of hospital stay, complications, recurrence, management and complications of the recurrence. A total of 244 patients, 134 males and 110 females with ameloblastomas were included in the study. Mean age was 47.4 years. In all, 81% of lesions were found in the mandible, whereas 19% were found in the maxilla. Mean size of included ameloblastomas was 38.9 mm. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 94 ameloblastomas, followed by segmental resection (60 patients), simple enucleation (46 patients), and marginal resection (40 patients). A recurrence (with a mean follow up of 5 years) was observed in 47 cases out of 244 ameloblastomas (19.3%). Segmental resection was associated with a low risk of recurrence (p = 0003), whereas enucleation plus curettage/peripheral ostectomy was associated with a high risk of recurrence (p = 0002). A multilocular radiographic appearance was associated with a high risk of recurrence (p < .05), as well as the benign solid/multicystic histologic type (p < .05). Within the limitations of the study it seems that the management of ameloblastomas will probably remain controversial even in the future. Balancing low surgical morbidity with a low recurrence rate is a difficult aim to reach.

Application of Patient-Specific Implants as Alternative Approach to Zygoma Defect Management - A Retrospective Study.

INTRODUCTION: Zygoma defects are a challenging clinical problem and are frequently connected with the alteration of facial harmony, horizontal asymmetry of the face, and significant functional deficit. The application of patient-specific implants (PSIs) has the potential to improve the effectiveness of zygoma defect management. The aim of this study was to evaluate the anatomic, esthetic, and functional outcomes of PSI application for zygoma reconstruction. MATERIALS AND METHODS: A retrospective study was conducted on data from 11 patients with zygoma defects who underwent a reconstruction procedure in which a PSI was applied and was followed for >1 year after surgery with the evaluation of esthetic and functional outcomes. Precision of PSI position and anatomy reconstruction was estimated by superimposition of the models with automatic point-to-point measurement and determination of the existing deviations between models. RESULTS: The mean follow-up period in our study was 21.6 ± 6.2 months (range 14-39 months). No major complications occurred in the postoperative period: There were no clinical or computed tomography symptoms of maxillary sinusitis, implant-related infection, or implant exposure. The mean deviation between the planned and real positions of PSIs in our series was 0.72 ± 0.41 mm. The mean deviation between the reconstructed zygomatic complex and the mirrored intact side in our series was 1.45 ± 0.7 mm. The mean volume difference between the intact and damaged orbits was 1.7 ± 0.8 mm3. DISCUSSION: The results of the present study support the wider clinical application of PSIs in orbital and zygoma reconstructions, as it is an effective option to achieve precise reconstruction of the complex zygoma anatomy.

Controversies in ameloblastoma management: evaluation of decision making, based on a retrospective analysis / Controversias en el manejo del ameloblastoma: Evaluación de la toma de decisiones, basada en un análisis retrospectivo

Background: The ameloblastoma management is still challenging to the high recurrence rates and significantmorbidity associated with radical treatment. The purpose of this 10-year retrospective study was to analyze theinfluence of ameloblastoma type and treatment strategy on the long-term outcomes and recurrence rates.Material and Methods: The retrospective analyses of 64 histologically-confirmed ameloblastoma cases was per-formed. The possible risk factors for recurrence and the development of complications were estimated statistically.Results: The treatment strategy applied for this group of patients was the following: thirty-four patients (53.1%)were treated conservatively with enucleation or extended bone curettage. Radical treatment (bone resection) wasapplied in 30 (46.9%) cases. The follow-up period ranged from 2 to 10 years (mean value 4.28 ± 3,26). General re-currence rate consisted 32.8%. This study did not find significant correlations between clinical or histopathologi-cal features of the ameloblastoma and the recurrence rate. The only factor that significantly influence recurrencerate was the treatment strategy (41% in conservative treatment vs 15% in radical treatment, p<0.05). Postoperativecomplications were observed in 42 patients (65.6%) and included face asymmetry and disfigurement (17.2%), tem-porary paresthesia of the inferior alveolar nerve (IAN) - 23.4%, permanent paresthesia of IAN - 20.3%, paresisof a marginal branch of the facial nerve - 6.3%, infection 12.5%, and swelling - 20.3%. The complication rates,esthetic and functional deficiency were significantly higher in radically treated patients (p<0.05)Conclusions: Our study confirms that higher recurrence rate is associated with conservative treatment for am-eloblastoma, while radical treatment leads to an increased number of postoperative complications that affect thepatient's quality of life.(AU)

Biomechanical evaluation of type p condylar head osteosynthesis using conventional small-fragment screws reinforced by a patient specific two-component plate.

BACKGROUND: The aim of this study was to evaluate via finite element analysis (FEA) the biomechanical behavior of conventional small-fragment screws reinforced by a patient-specific plate in type p condylar head. METHODS: A finite element model of the mandible was created using Mimics 12.1 software. A type p condylar head fracture was simulated in the right condyle, and the left condyle was used as a control. Two patterns of fixation were investigated: conventional two-screw fixation and the same fixation system reinforced with a small, patient-specific plate. Surface models were imported into the software Ansys 5.7for further volume mesh generation. RESULTS: The highest stress gradients were observed in the cortical layer of the lateral fragment, located near the screw. The conventional fixation method resulted in equivalent stresses 2 to 10 times greater than the reinforced method. Rigidity of fixation in the reinforced method increased up to 1.25-3 times compared to the conventional two-screw technique. CONCLUSION: This study's findings suggest significant benefits in unfavorable biomechanical conditions from reinforcement of the standard two-screw fixation of condylar head fractures with a small, patient-specific plate acting as a washer.

Application of CAD/CAM technology for surgical treatment of condylar head fractures: A preliminary study.

OBJECTIVES: The aim of the present study was to improve the accuracy and reliability of ORIF in patients with condylar head fractures (CHFs) by developing a design for patient specific fixators, navigation and repositioning guides, as well as the algorithms of their clinical application. MATERIALS AND METHODS: 14 patients with 16 CHFs were treated by ORIF with the use of CAD/CAM technology. After virtual reduction of the bony fragments, the appropriate length and diameter of the screws was chosen. In biomechanically unfavorable cases (type p) patient specific reinforcement plates were used together with the positional screws for reinforcement of the bone-fixator system. And in cases of severely comminuted fractures patient specific 3-D plate was applied. RESULTS: The CT data, obtained immediately after the operation revealed the good anatomical reduction. Any deviations of the small fragments noted were near 1 mm in all cases. Postoperative clinical examination at 3 months follow up showed good occlusion and mouth opening not less than 3 cm in all patients. The lateral and anterior mobility of the mandible was restored with small limitations of protrusive mobility in 1 case. All the patients were satisfied with the outcomes. CONCLUSIONS: The application of the CAD/CAM technologies and the new design of the surgical guides and patient specific reinforcement plates for CHFs helps to improve the accuracy and quality of fragments reduction and stability of fixation with minimal risks of intraoperative complications. CLINICAL RELEVANCE: CAD/CAM technologies improve the clinical effectiveness of treatment patients with the CHFs.

Radiological changes in maxillary sinus morphology after lateral sinus floor augmentation.

<b>Background:</b> Restoration of the masticatory function in patients with edentulous posterior maxilla is often challenging due to the severe atrophy of the alveolar ridges and proximity of the maxillary sinus, resulting in insufficient bone quantity for implant-supported dentures. <br><b>Aim:</b> The purpose of this study was to analyze the changes in Schneiderian membrane thickness after lateral sinus floor augmentation (LSFA) using cone beam computed tomography (CBCT). <br><b>Material and methods:</b> WLSFA procedures using different bone grafting materials were performed in 87 patients, operated on in two clinical institutions from 2016 to 2018. CBCT examination was performed in all patients before the LSFA procedure, at 1 month after surgery, and after 6 months, before implant placement or loading. <br><b>Results: </b>Minor r adiological changes in mucous membrane morphology were observed preoperatively in 17.1% of patients. Postoperative CBCT in the early postsurgical period demonstrated that the number of intact non-specific sinuses decreased significantly, i.e. from 86.7% to 26.7%. The number of cases with local hypertrophia of the mucous membrane increased from 20.3% to 26.7%. Mucosal thickening was observed in 41.7% vs 7.5%. The number of intact sinuses increased to 57.8%. The number of cases with local membrane hypertrophia also increased - to 37.4%. The number of cases with mucosal thickening or fluid accumulation decreased significantly to 11.8 and 5.3% respectively. In 2 cases the development of chronic sinusitis required secondary surgeries. <br><b>Conclusion:</b> The present retrospective study revealed that minor radiological changes in the morphology of the maxillary sinus mucosa were observed preoperatively in 17.1% of patients who underwent LSFA procedures. In the early and late postoperative period their frequency increased to 68.5% and 47.1%, respectively. However, the clinical signs of sinusitis developed only in 19.26% of patients. No significant correlations were found between the frequency and severity of postoperative radiological changes and residual bone height, sinus anatomy, initial state of the mucous membrane and type of the grafting material.