Acesso transconjutival com cantotomia lateral para abordagem do completo orbito-zigomático-maxilar: relato de caso / Transconjutival access with side cantotomy to approach the orbito-zygomatic-maxillary complex: case report

Objetivo: relatar um caso clínico, embasando os aspectos relativos à técnica cirúrgica transconjutival com cantotomia lateral como tratamento para fratura de COZM. Relato de caso: Paciente, gênero masculino, compareceu ao Serviço de Cirurgia e Traumatologia Bucomaxilofacial do Hospital Geral do Estado (HGE), vítima de acidente motociclístico, apresentando distopia ocular, degrau ósseo em rebordo infraorbitário direito, perda de projeção malar direita, abertura bucal limitada com desvio ipsilateral e distopia oclusal com sinais sugestivos de fratura do complexo-orbito-zigomático-maxilar direito, juntamente com fratura complexa da mandíbula. A abordagem cirúrgica para acessar o COZM contou com a técnica de incisão transconjuntival com cantotomia lateral para uma melhor visualização dos cotos ósseos fraturados. Considerações finais: a escolha por esse tipo de acesso resultou em uma abordagem cirúrgica bem-sucedida, proporcionando segurança na visualização do campo cirúrgico para posterior reabilitação do paciente, estabelecendo uma devolutiva estética e funcional, cicatriz imperceptível e consequentemente um melhor prognóstico para o paciente.(AU)

Objective: to report a clinical case, basing the aspects related to the transconjunctival surgical technique with lateral canthotomy as a treatment for COZM fracture. Case report: Patient, male gender, attended the Oral and Maxillofacial Surgery and Traumatology Service of the General Hospital of the State (HGE), victim of a motorcycle accident, presenting ocular dystopia, bone step in the right infraorbital ridge, loss of right malar projection, mouth opening limited with ipsilateral deviation and occlusal dystopia with signs suggestive of a fracture of the right orbito-zygomatico-maxillary complex along with a complex fracture of the mandible. The surgical approach to access the contoured COZM with the transconjunctival incision technique with lateral canthotomy for better visualization of the fractured bone stumps. Final considerations: the choice for this type of access resulted in a successful behavioral approach, providing security in the experience of the respiratory field for subsequent rehabilitation of the patient, establishing a devolutionary and functional aesthetics, imperceptible healing and, consequently, a better prognosis for the patient.(AU)

A Zygomatic Bone Study Using Virtual Dental Implant Planning Software.

This study evaluated the anatomical factors that influence the virtual planning of zygomatic implants by using cone-beam computerized tomography (CBCT) scans. CBCT scans of 268 edentulous patients were transferred to specialized implant planning software for the following measurements: maxillo-sinus concavity size (small, medium, and large), zygoma width, implant insertion angle, implant length, and implant apical anchorage. Concavity sizes found were as follows: 34.95% small, 52.30% medium, and 7.35% large. The mean insertion angle was 43.2 degrees, and the average implant apical anchorage was 9.1 mm. The most frequent implant length was 40 mm. Significant differences were found when the different types of concavities in relation to the installation angle, the distance of the apical portion of the implant in contact with the zygomatic bone, and the lateral-lateral thickness of the zygomatic bone were compared (P < .001). Medium-sized maxillary sinus concavity presented greater apical anchorage of the implant (9.7 mm) and was the most frequent type (52.30%). The zygomatic bone is a viable site for zygomatic fixtures, and the use of specialized implant planning software is an important tool to achieve predictable outcomes for zygomatic implants and allows good visualization of the relation between implants and anatomical structures.

Impact of bilateral nasal polyposis on the interoptic and interzygomatic distance.

PURPOSE: To identify and determine variations on eye distance in patients with bilateral nasal polyposis (BNP) compared to a healthy control group. METHODS: This is a case-control study that included 20 BNP patients and 40 healthy controls. We included all patients with BNP confirmed by pathology and a computed tomography scan. A healthy control group was admitted, filtered by the exclusion criteria of nasal polyposis, craniofacial malformations, and encephalocele. Paranasal sinus CT scans were performed in all participants, and two measures were evaluated, the interoptic (soft tissue) and the interzygomatic (bone structure) distances. RESULTS: A total of 20 BNP subjects, 13 (65%) male and 7 (35%) female, with a mean age of 38.8 years, and 40 healthy controls, 16 (40%) male and 24 (60%) female with a mean age of 43.2 years, were included. The mean interoptic distance was 69.7 mm (71.9 mm men, 66.4 mm women) and interzygomatic distance was 103.1 mm (104.5 mm men, 100.6 mm women). A significant increase of the interoptic (p < 0.001) and interzygomatic (p < 0.002) measurements was found in patients with polyposis compared to the controls. In the receptor operative curve analysis, the interoptic distance had an area under a curve of 96% and the threshold that maximizes the sensitivity and specificity was 59.85 mm (sensitivity 90%, specificity 95%, PPV 90%, NPV 95%). CONCLUSIONS: An increase in ocular and orbital distances was identified in patients with BNP. Polyposis may be identified by measuring eye separation. The established cut point distance identifies patients that may benefit from follow-up. Further research in this study line is suggested.

Tomographic and anatomical study of the orbit and nasolacrimal duct in capybaras (Hydrochoerus hydrochaeris-Linnaeus, 1766).

The objective of this study was to describe the reference values of cranial measurements of capybaras, correlating the ocular orbit with the nasolacrimal duct. The documentation of its results can contribute to standardizing characteristics of anatomical normality and favouring the correct diagnosis and treatment of changes. The capybara carcasses, maintained by freezing, were distributed in two groups (G) designated GA (n = 12) adult animals (A) and GY (n = 13) for young animals (Y). All subjects underwent dacryocystography examination by computed tomography (CT) and cranial measurements. Descriptive analyses of cranial and nasolacrimal duct measurements and statistical analysis of the Pearson correlation with the variable weight were performed. In GA, there was no correlation between the nasolacrimal and cranial duct measurements. However, in the GY, a correlation was verified with facial length (r = .6233), facial width (r = .5771), cranial height (r = .6981), cranial length (r = .7116), total right length (r = .7517) and left length (r = .7999). Thus, in the young animals, cranial length measurements were strongly correlated with nasolacrimal duct lengths. However, this biological behaviour was not observed in adults, demonstrating stability in development. The capybara's ocular orbit was found to be circular and incomplete, with developed zygomatic process of the maxilla. CT dacryocystography is indicated to evaluate the nasolacrimal canal pathway in capybaras, emphasizing the importance of normal anatomical study to aid in treating animals affected by diseases.

Maxillary zygomatic hexagonal implant system (MZH system) for severe resorption: a new technique.

INTRODUCTION: The biomechanical demands of the severely resorbed maxilla have prompted the search for alternative points of anchorage for zygomatic implants that allows stabilizing a prosthesis in young patients (30 years old or more) for restitution of function and form. The purpose of this study is to describe the protocol of zygomatic hexagonal implants in patients with severe maxillary bone resorption. MATERIALS AND METHODS: Ten patients with severe maxillary resorption were treated with hexagonal implants system, they were evaluated at the preoperative and the postoperative periods for a minimal of 24 months, and the evaluation was clinical and trough conventional radiographs and CT scans. Six implants according to prosthetic prior planning were placed in each patient. Anteroposterior severely resorbed maxilla was evidence. Patients were rehabilitated with immediate provisional prosthesis. Ten days after surgery, definitive prosthesis metal structures were designed and adapted. RESULTS: Force distribution and load concentration were balanced; adjustment of the metal bar was passive. Correction of skeletal relationship was evident. No fatigue in the later additions in controls was observable. No complications were found in the immediate postoperative period and late (6-24 months), no patients dropped out from the study, and all were followed up to 24 months. CONCLUSIONS: The zygomatic hexagonal implants' protocol guarantees barrier function, biomechanical stability, load distribution, and preventing fatigue bone/implant interface, which allows distributing of the forces through the pillars, anterior masticatory load reduction, and correcting the skeletal class III type which occurs in patients with severe resorption.

Assessing bone thickness in the infrazygomatic crest area aiming the orthodontic miniplates positioning: a tomographic study.

INTRODUCTION:: Due to the increasing use of miniplates for anchorage purposes in orthodontics, it is very important to know more about infrazigomatic crest anatomy (thickness), in adult patients. OBJECTIVES:: Evaluate the infrazygomatic crest region thickness, in adult (male and female) patients. METHODS:: Cone-beam computerized tomography (CBCT) images from 40 patients were used to assess cross-sectional measurements of the infrazygomatic crest region. Measurement 1 considered thickness 2 mm above the distobuccal root of the permanent maxillary first molar, while measurement 2 was taken 2 mm above the first measurement. RESULTS:: The mean thickness of the infrazygomatic crest in males was 3.55 mm for measurement 1 and 2.84 mm for measurement 2, while in females these were 2.37 mm and 2.24 mm, respectively. CONCLUSION:: The authors concluded that the overall mean thickness of the infrazygomatic crest was 2.49 mm with respect to measurement 1, and 2.29 mm for measurement 2, with no statistically significant differences between gender.

Assessing bone thickness in the infrazygomatic crest area aiming the orthodontic miniplates positioning: a tomographic study

ABSTRACT Introduction: Due to the increasing use of miniplates for anchorage purposes in orthodontics, it is very important to know more about infrazigomatic crest anatomy (thickness), in adult patients. Objectives: Evaluate the infrazygomatic crest region thickness, in adult (male and female) patients. Methods: Cone-beam computerized tomography (CBCT) images from 40 patients were used to assess cross-sectional measurements of the infrazygomatic crest region. Measurement 1 considered thickness 2 mm above the distobuccal root of the permanent maxillary first molar, while measurement 2 was taken 2 mm above the first measurement. Results: The mean thickness of the infrazygomatic crest in males was 3.55 mm for measurement 1 and 2.84 mm for measurement 2, while in females these were 2.37 mm and 2.24 mm, respectively. Conclusion: The authors concluded that the overall mean thickness of the infrazygomatic crest was 2.49 mm with respect to measurement 1, and 2.29 mm for measurement 2, with no statistically significant differences between gender.

RESUMO Introdução: devido ao aumento do uso de miniplacas para ancoragem em Ortodontia, torna-se de fundamental importância compreender melhor a anatomia da crista infrazigomática (espessura) em pacientes adultos. Objetivos: avaliar a espessura da crista infrazigomática em pacientes adultos (sexos feminino e masculino). Métodos: foram utilizadas tomografias computadorizadas de feixe cônico (TCFC) de 40 pacientes, para avaliar medidas da região da crista infrazigomática, no sentido transversal. A Medida 1 verificou a espessura mm acima da raiz distovestibular do primeiro molar permanente superior, enquanto a Medida 2 foi realizada 2 mm acima da primeira medida. Resultados: a espessura média da crista infrazigomática encontrada no sexo masculino foi de 3,55 mm para a Medida 1 e de 2,84 mm para a Medida 2, e no sexo feminino foi de 2,37 mm e de 2,24 mm, respectivamente. Conclusão: os autores puderam constatar que a espessura média da crista infrazigomática foi de 2,49 mm para a Medida 1, e de 2,29 mm para a Medida 2, sem diferença estatisticamente significativa entre os sexos.

Zygomaticomaxillary suture maturation: A predictor of maxillary protraction? Part I - A classification method.

OBJECTIVE: The aim of this study was to present a method of classifying the maturational level of the zygomaticomaxillary sutures (ZMSs). METHODS: Cone-beam CT (CBCT) images from 74 subjects (5.6-58.4 years) were examined to define the radiographic stages of ZMS maturation. Five stages of maturation of the ZMS were identified and defined: Stage A-uniform high-density sutural line, with no or little interdigitation; Stage B-scalloped appearance of the high-density sutural line; Stage C-two parallel, scalloped, high-density lines, separated in some areas by small low-density spaces; Stage D-fusion in the inferior portion of the suture; and Stage E-complete fusion. Intra- and inter-examiner agreements were evaluated by weighted kappa tests. RESULTS: The intra- and inter-examiners reproducibility values demonstrated substantial to almost perfect agreement. No fusion of ZMSs was observed in patients up to 10 years of age. From 10 to 15 years, all maturational stages were identified. After 15 years of age, the majority of patients showed fusion of ZMSs. CONCLUSIONS: The classification of ZMS maturation using CBCT is a reliable method that allows the assessment of the morphology of the ZMSs in the individual patient.

Evaluation of the zygomatic bone by cone beam computed tomography.

PURPOSE: The zygomatic bone (ZB) has been an effective option in the rehabilitation of the atrophic edentulous maxilla, in restoration of the low projection of the maxilla and in insertion of miniplates in maxillofacial fracture; it is situated near to air cells. In this way, the aim of this study was to evaluate the ZB by means of cone beam computed tomography (CBCT) images to determine if this bone can present characteristics similar to pneumatizations (CSPZB) and, in affirmative case, to determine its distribution concerning the age, gender, laterality and type. MATERIALS AND METHODS: CBCT of 698 patients (1.396 ZB) were evaluated to determine the presence of CSPZB. The age and gender were recorded for all patients and, for the cases of CSPZB, laterality and type (unilocular or multilocular) were noted. Its prevalence was correlated with gender, age and laterality by statistical analyses (Chi-squared test). RESULTS: 3.3% of individuals presented CSPZB. If we consider all zygomatic bones, CSPZB was in 2.8%. Of these cases, 30.5% were unilateral and 69.5% bilateral; all presented multilocular pattern. There was no statistical correlation between CSPZB and gender or age (p = 0.15 and 0.63, respectively), neither between CSPZB and laterality (p = 0.39). CONCLUSION: It was found an altered pattern similar to pneumatization in ZB; however, its prevalence was low (3.3% of the studied population). Our results indicate that the ZB should be evaluated in tomographic images prior to surgical treatments carefully.

An assessment of the maxilla after rapid maxillary expansion using cone beam computed tomography in growing children.

INTRODUCTION: With the advent of cone beam computed tomography (CBCT), it is now possible to quantitatively evaluate the effects of rapid maxillary expansion (RME) on the entire maxillary complex in growing patients. OBJECTIVE: The purpose of this study is to use three-dimensional images to evaluate the displacement that occurs at the circummaxillary sutures (frontonasal, zygomaticomaxillary, intermaxillary, midpalatal, and transpalatal sutures) following rapid maxillary expansion in growing children. METHODS: The CBCT scans of 25 consecutively treated RME patients (10 male, 15 female) with mean age of 12.3±2.6 years, were examined before expansion and immediately following the last activation of the expansion appliance. RESULTS: Statistically significant (P<0.05) amounts of separation were found for the displacement of the bones of the frontonasal suture, the intermaxillary suture, the zygomaticomaxillary sutures, and the midpalatal suture. The change in angulation of the maxillary first molars due to RME was also statistically significant. There was no statistically significant displacement of the transpalatal suture. CONCLUSIONS: Rapid maxillary expansion results in significant displacement of the bones of circummaxillary sutures in growing children.

Cone beam tomographic study of facial structures characteristics at rest and wide smile, and their correlation with the facial types.

OBJECTIVE: To determine the characteristics of facial soft tissues at rest and wide smile, and their possible relation to the facial type. METHODS: We analyzed a sample of forty-eight young female adults, aged between 19.10 and 40 years old, with a mean age of 30.9 years, who had balanced profile and passive lip seal. Cone beam computed tomographies were performed at rest and wide smile postures on the entire sample which was divided into three groups according to individual facial types. Soft tissue features analysis of the lips, nose, zygoma and chin were done in sagittal, axial and frontal axis tomographic views. RESULTS: No differences were observed in any of the facial type variables for the static analysis of facial structures at both rest and wide smile postures. Dynamic analysis showed that brachifacial types are more sensitive to movement, presenting greater sagittal lip contraction. However, the lip movement produced by this type of face results in a narrow smile, with smaller tooth exposure area when compared with other facial types. CONCLUSIONS: Findings pointed out that the position of the upper lip should be ahead of the lower lip, and the latter, ahead of the pogonion. It was also found that the facial type does not impact the positioning of these structures. Additionally, the use of cone beam computed tomography may be a valuable method to study craniofacial features.

Three-dimensional analysis of maxillary changes associated with facemask and rapid maxillary expansion compared with bone anchored maxillary protraction.

INTRODUCTION: Our objectives in this study were to evaluate in 3 dimensions the growth and treatment effects on the midface and the maxillary dentition produced by facemask therapy in association with rapid maxillary expansion (RME/FM) compared with bone-anchored maxillary protraction (BAMP). METHODS: Forty-six patients with Class III malocclusion were treated with either RME/FM (n = 21) or BAMP (n = 25). Three-dimensional models generated from cone-beam computed tomographic scans, taken before and after approximately 1 year of treatment, were registered on the anterior cranial base and measured using color-coded maps and semitransparent overlays. RESULTS: The skeletal changes in the maxilla and the right and left zygomas were on average 2.6 mm in the RME/FM group and 3.7 mm in the BAMP group; these were different statistically. Seven RME/FM patients and 4 BAMP patients had a predominantly vertical displacement of the maxilla. The dental changes at the maxillary incisors were on average 3.2 mm in the RME/FM group and 4.3 mm in the BAMP group. Ten RME/FM patients had greater dental compensations than skeletal changes. CONCLUSIONS: This 3-dimensional study shows that orthopedic changes can be obtained with both RME/FM and BAMP treatments, with protraction of the maxilla and the zygomas. Approximately half of the RME/FM patients had greater dental than skeletal changes, and a third of the RME/FM compared with 17% of the BAMP patients had a predominantly vertical maxillary displacement.

Zygomaticomaxillary complex fracture in a zygomatic bone affected by monostotic fibrous dysplasia: a very rare association.

The association between fibrous dysplasia (FD) and fractures is very rare. This paper reports the case of a zygomaticomaxillary complex fracture in a bone affected by FD, a 29-year-old man who was involved in a bicycle accident and who subsequently presented with a zygomaticomaxillary complex fracture. Computed tomography revealed multiple fractures of the left zygomaticomaxillary complex with dysplastic bone alterations. Fracture lines occurred near transitional areas between the lesion and healthy bone. The patient was treated through an intraoral approach by an open reduction and internal fixation procedure, using a titanium miniplate and screws. An incisional biopsy was performed through the maxillary sinus to confirm the diagnosis of FD. After 12 months of follow-up, there were no postoperative complications. This paper reports a rare association thought to be caused by irregular trabecular bone deposition, which increases bone thickness/resiliency and thus increases its clinical fracture resistance.

The buccal fat pad flap: an option to prevent and treat complications regarding complex zygomatic implant surgery. Preliminary report.

PURPOSE: To evaluate the use of the buccal fat pad flap (BFPF) technique as an option to prevent complications in the treatment of patients with atrophic maxillae rehabilitated after complex zygomatic implant surgery. MATERIALS AND METHODS: A retrospective study was made of completely edentulous patients submitted to zygomatic implant surgery between May 2005 and November 2007. Patients with severely atrophic maxillae received conventional and zygomatic implants and were followed after the implants were loaded. Preoperative evaluation included panoramic radiography and computed tomographic scans of the maxilla to identify the anatomic conditions and presence of pathology. RESULTS: Eight male patients with a mean age of 57 years and atrophic maxillae were rehabilitated with zygomatic implants placed using the BFPF technique. The BFPF technique was used in complex situations, including oroantral communication-associated sites, areas that had lost the sinus wall, and extrasinus implant placement. A total of 16 conventional implants, 4 long (21-mm) tilted implants, and 22 zygomatic implants was placed. The patients were rehabilitated with fixed prostheses and were followed for a minimum of 15 months. None of the conventional implants failed and none of the zygomatic implants failed or presented with soft tissue complications. CONCLUSION: The BFPF presented a high success rate, demonstrating that it is a viable and predictable treatment option to prevent and treat soft tissue complications in complex zygomatic implant surgery.

Evaluation of fixation techniques with titanium plates and Kirschner wires for zygoma fractures: preliminary study.

OBJECTIVE: The aim of the present study was to assess the quality of treatment using two reduction and fixation techniques for zygoma fractures. PATIENTS AND METHODS: A randomized clinical trial was carried out involving a sample of 10 patients with Knight and North type III, IV and V zygoma fractures divided into two groups. One group underwent the closed reduction technique and fixation with Kirschner wire and the other group underwent the open reduction technique and fixation with titanium plates. The groups were submitted to subjective evaluation based on the patient's perception of areas of deformity and paresthesia as well as the measurement of range of mouth opening and pain upon mouth opening in the preoperative (T0) and postoperative (T1) periods. The assessment of bone reduction quality was performed using quantifiable points (lateral wall of the orbit, anteroposterior projection of the zygoma and ocular globe projection), measured based on tomographic images. RESULTS: Seventy percent of the patients remained with paresthesia and 20% remained with the complaint of deformity at T1. Mouth opening range increased in both groups at T1. In the overall sample, mean total disjunction of the lateral wall of the orbit and the difference in the anteroposterior projection of the zygoma were reduced between T0 and T1 (4.36 mm to 1.25 mm and 6.94 mm to 2.86 mm, respectively). There was also a reduction in ocular globe projection in both groups between T0 and T1. CONCLUSIONS: Both techniques achieved adequate reduction of zygoma fractures in the postoperative period.

Coronoid process hyperplasia: an unusual cause of mandibular hypomobility.

A large number of disorders affecting the masticatory system can cause restriction of mouth opening. The most common conditions related to this problem are those involving the temporomandibular joint (TMJ) and the masticatory muscles, when facial pain also is an usual finding. Congenital or developmental mandibular disorders are also possible causes for mouth opening limitation, although in a very small prevalence. Coronoid process hyperplasia (CPH) is an example of these cases, characterized by an excessive coronoid process growing, where mandibular movements become limited by the impaction of this structure on the posterior portion of the zygomatic bone. This condition is rare, painless, usually bilateral and progressive, affecting mainly men. Diagnosis of CPH is made based on clinical signs of mouth opening limitation together with imaging exams, especially panoramic radiography and computerized tomography (CT). Treatment is exclusively surgical. This paper presents a case of a male patient with bilateral coronoid process hyperplasia, initially diagnosed with bilateral disk displacement without reduction, and successfully treated with intraoral coronoidectomy. It is emphasized the importance of differential diagnosis for a correct diagnosis and, consequently, effective management strategy.

Fracture of the coronoid process, sphenoid bone, zygoma, and zygomatic arch after a firearm injury.

A rare case of fracture of the coronoid process, sphenoid bone, zygoma, and zygomatic arch caused by a firearm is described. A 25-year-old man was hit in the face with a bullet, resulting in restricted mouth opening, difficulty chewing, and pain when opening the mouth. The clinical examination revealed a perforating wound in the right parotid region. A computed tomographic scan revealed a comminuted fracture of the left coronoid process with the bullet stopping in the intact left coronoid process. Treatment was bilateral coronoidectomy associated with speech therapy and was successful. Details of the clinical signs, computed tomography, treatment, and follow-up are presented.

'Inverse' temporomandibular joint dislocation.

Temporomandibular joint (TMJ) dislocation can be classified into four groups (anterior, posterior, lateral, and superior) depending on the direction of displacement and the location of the condylar head. All the groups are rare except for anterior dislocation. 'Inverse' TMJ dislocation is a bilateral anterior and superior dislocation with impaction of the mandible over the maxilla; to the authors' knowledge only two cases have previously been reported in the literature. Inverse TMJ dislocation has unique clinical and radiographic findings, which are described for this case.

Use of 4 immediately loaded zygomatic fixtures for retreatment of atrophic edentulous maxilla after complications of maxillary reconstruction.

This article reports the 20-month clinical outcome of the use of 4 zygomatic implants with immediate occlusal loading and reverse planning for the retreatment of atrophic edentulous maxilla after failed rehabilitation with autogenous bone graft reconstruction and maxillary implants. The intraoral clinical examination revealed mispositioned and loosened implants underneath a maxillary complete denture. The panoramic radiograph showed 6 maxillary implants. One implant was displaced into the right maxillary sinus, and the implant anchored in the region of tooth 21 was fractured. The other implants presented peri-implant bone loss. The implants anchored in the regions of teeth 21 to 23 and 11 to 13 were first removed. After 2 months, the reverse planning started with placement of 4 zygomatic fixtures, removal of the implants migrated into the sinus cavity and anchored in the region of tooth 17, and installation of a fixed denture. After 20 months of follow-up, no painful symptoms, peri-implant inflammation or infection, implant instability, or bone resorption was observed. The outcomes of this case confirm that the zygoma can offer a predictable anchorage and support function for a fixed denture in severely resorbed maxillae.