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.

Imaging and histopathological features of Jacob's disease: a case study

A pathologically elongated coronoid process forming a joint with the zygomatic arch and bone is termed as "Jacob's disease." Herein, we present a case of Jacob's disease, which has rarely been reported in the literature. Moreover, very few cases have been reported from the Indian subcontinent. A 28 years-old male reported to us with progressive restriction of mouth opening. After detailed imaging, coronoidectomy was performed through an intraoral approach. A mushroom-shaped gross specimen was obtained. Osteochondroma of the coronoid process was diagnosed based on the histopathologic examination of the excised tissue. Although Jacob's disease is seldom considered in the list of differential diagnoses for restricted mouth opening, our case highlights the need for evaluation of the coronoid process, which is usually ignored during routine radiographic examination. The report also highlights the miniscule incidence of this condition in the available literature.

Surgical management of primary chronic osteomyelitis of the jaws in children: a prospective analysis of five cases and review of the literature

INTRODUCTION

Primary chronic osteomyelitis (PCO) of the jaws is an uncommon non-suppurative inflammatory disease of unknown origin. Although the disease is not age-specific, only sparse cases with onset during childhood or adolescence have been reported in the literature.

PURPOSE

This study seeks to present five cases of maxillofacial PCO in children and to evaluate the effectiveness of the applied therapeutic protocol. A review of the literature concerning diagnosis and treatment of PCO with special emphasis on surgical therapy is also performed.

PATIENTS AND METHODS

Demographic data, clinical, radiographic and histopathologic findings, blood tests results, and the treatment protocol applied to five young patients suffering from PCO and referred to the Department of Oral and Maxillofacial Surgery at "A. & P. Kyriakou Children's Hospital" over the past 5 years are presented. Decortication and contouring of the affected bone were performed; antibiotics were administered for a short period of time and the patients remained under follow-up evaluation.

RESULTS

The posterior mandible was affected in four cases and the maxilla-zygomatic bone in one case. All patients showed remission of signs and symptoms after surgical treatment. The postsurgical clinical course was uneventful in all cases. However, recurrences have been noted, as reported in the literature.

CONCLUSION

PCO of the jaws is a complex clinical entity, presenting both a diagnostic and therapeutic challenge, especially in young patients. Surgical treatment in conjunction with antibiotics and non-steroid anti-inflammatory drugs proved to be beneficial and to improve considerably the patients' quality of life. Nevertheless, exacerbation of the disease may appear and regular follow-up of the patients is required.

A proposed classification for zygomatic implant patient based on the zygoma anatomy guided approach (ZAGA): a cross-sectional survey

PURPOSE

The aim of the present cross-sectional study was to propose a classification system based on a cross-sectional survey of zygomatic implant cases.

MATERIALS AND METHODS

Cone beam computerised tomography (CBCT) postoperative images and clinical intra-surgery photographs of 200 sites corresponding to 100 patients, treated with a total of 198 zygomatic implants in the maxilla according to an anatomy-driven prosthetic approach, were reviewed with regard to anatomy and pathway of the zygomatic implant body. The patients were consecutively selected independently of the type of surgery performed, with the unique requirement of a post-surgical CBCT performed at the moment of selection. Of special interest was the morphology of the lateral sinus wall, residual alveolar crest and the zygomatic buttress. An attempt was made to divide the patients into groups, describing typical anatomies and implant pathways.

RESULTS

Five basic skeletal forms of the zygomatic buttress-alveolar crest complex and subsequent implant pathways could be identified in a sample of 100 patients. Out of them, 62% were female and 38% male, with ages varying between 36 and 83 years (mean age 59.6, SD: 9.67). The five groups were classified as ZAGA 0 to 4 representing 15%, 49%, 20.5%, 9% and 6.5% of the studied sites, respectively. Intra-individual anatomical differences affecting the zygomatic buttress-alveolar crest complex was also found in 58% of the patients.

CONCLUSIONS

Five typical anatomical and implant pathway situations could be identified. A classification system comprising five groups named ZAGA 0 to 4 is proposed. Anatomical intra-individual differences were also found in the 58% of the studied population. It is believed that the proposed classification system is useful for categorising zygomatic implant cases for therapy planning and for scientific follow-up purposes.

A new method to eliminate the risk of maxillary sinusitis with zygomatic implants

PURPOSE

A new approach for zygomatic implant placement was proposed to eliminate the risk of maxillary sinusitis related to the procedure.

MATERIALS AND METHODS

A prospective study of this new approach was conducted, and consecutive patients treated between June 2007 and December 2008 were included. An extended sinus lift with retained bone window was performed, such that zygomatic implants were placed completely outside the displaced maxillary sinuses. All patients were followed up radiologically at regular intervals using cone beam computed tomography to evaluate the status of the zygomatic implants and the condition of the maxillary sinuses.

RESULTS

Sixteen patients (9 women and 7 men with a mean age of 60) were treated with 37 zygomatic implants. Within the period of investigation from 6 months to 24 months, there were no failed zygomatic implants, and no instances of maxillary sinusitis were reported.

CONCLUSIONS

The new approach that combined the zygomatic implant placement with the extended sinus lift procedure was predictable and fulfilled the purpose of lowering the risk of maxillary sinusitis.

Observation of buccal foramen in mandibular body using cone-beam computed tomography

The location and course of the mandibular canal and multiple mental foramina are important in dental implant insertion and any surgical procedures involving the mandible. The purpose of the present investigation was to assess buccal foramen presence in the mandible using cone-beam computed tomography (CBCT) images. A total of 84 patients were enrolled in this investigation. Buccal foramen presence in the mandibular body, which was defined as a buccal bone defect of the bony canal penetrating through the buccal cortical bone, was assessed using two- and three-dimensional CBCT images. Buccal foramen presence, located from the median to molar regions, was observed in 44% of patients. There was no significant difference among gender and age. Also, a buccal foramen showing continuity with the mandibular canal was observed in 7.1% of patients. Buccal foramen presence in the mandibular body could be assessed in detail using CBCT images.

A very rare complication of acute sinusitis: subgaleal abscess

A 12-year-old girl presented with a swollen right eye with three days of pain and a diffused swollen frontal region and head lasting for one day. On the computed tomography with contrast, diffused collection was detected in the subgaleal regions and subperiosteal of the right orbita. It was observed that she had bilateral maxillary, ethmoidal, and frontal sinusitis and an infected bilateral middle concha bullosa in the right side. No symptoms of intracranial complication and osteomyelitis in the frontal or other calvarial bones were determined. This case presentation is thought to be the first one in literature that is an acute sinusitis without an intracranial complication and osteomyelitis, but with a diffused subgaleal abscess resulting from a subperiosteal abscess.

Image guided oral implantology and its application in the placement of zygoma implants

The application of zygoma implants proposes a successful treatment for functional reconstruction of maxillary defects. However, the placement of zygoma implants is not without risk due to anatomically complex operation sites. Aiming at minimizing the risks and improving the precision of the surgery, an image guided oral implantology system (IGOIS) is presented in this study to transfer the preoperative plan accurately to the operating theatre. The principle of IGOIS is introduced in detail, including the framework, 3D-reconstruction, preoperative planning, registration, and the motion tracking algorithm. The phantom experiment shows that fiducial registration error (FRE) and TRE (target registration error) of IGOIS are, respectively, 1.12mm and 1.35mm. With respect to the overall accuracy, the average distance deviations at the coronal and apical point of the implant are, respectively, 1.36+/-0.59mm and 1.57+/-0.59mm, while average angle deviation between the axes of the planned and the actual implant is 4.1 degrees +/-0.9 degrees . A clinical report for a patient with a severely atrophic maxilla demonstrates that the major advantage of this computer-aided navigation technology lies in its accuracy, reliability, and flexibility.

Three-dimensional reconstruction after removal of zygomatic intraosseous hemangioma

INTRODUCTION

Intraosseous hemangioma, especially in the zygomatic area, is a very rare pathologic condition among the osseous tumors of the head and neck area. Clinical presentation includes a painless mass with progressive growth and hard consistence. Diagnosis is performed by means of computed tomography (CT). Treatment includes radical en bloc surgical excision with healthy bone margins in order to avoid blood loss. Previous embolization is not necessary. Bony defect reconstruction must be performed to avoid secondary deformities.

CASE REPORT

We present a case report of a 30-year-old female presenting a progressive painless swelling in the malar and zygomatic regions. CT scan demonstrated a right zygomatic lesion that extended into the orbital floor and lateral orbital wall, affecting also the zygomatic arch. The biopsy revealed an intraosseous hemangioma. Treatment was performed including an en bloc resection with healthy bony margins and primary reconstruction with calvarian bone graft in association with galea-pericranium flap.

[Examination of axial zygomatic arch radiographs using the bisector method]

An axial radiograph of the zygomatic arch is taken in cases of patients with facial traumatic injury. Maintaining the patient's head in the retroflex position to take such axial radiographs is sometimes difficult because of medical conditions. In addition, since different positioning techniques for retroflexion are used by radiological technologists, the visibility of the zygomatic arch was poorly in reproduced. We contrived a novel technique for use in taking a zygomatic arch radiograph. We call it the "bisector method," and it does not require the retroflex position. We can take a zygomatic arch radiograph equal in quality to conventional axial radiographs (retroflex position) by exposing X-rays perpendicularly to the bisector of the angle between the casette and the zygomatic arch. This bisector method is relatively easy in that it does not require either the retroflex position or the expertise of a radiological technologist.

Three-dimensional analysis of changes of the malar-midfacial region after LeFort I osteotomy and maxillary advancement

AIM

It has been the objective of the present prospective study to assess visible volume changes of the facial soft tissue after LeFort I osteotomy with advancement and to determine the soft-tissue-to-hard-tissue ratios of advancement.

PATIENTS AND METHODS

Twenty adult patients (ten female, ten male, mean age 33.9 +/- 14.9 years) received a LeFort I osteotomy with advancement because of a maxillary protrusion. Lateral skull radiographs and optical three-dimensional (3D) scans of the facial surface were assessed preoperatively and 12 months after surgery. The lateral skull radiographs were used to carry out standard linear and angular cephalometric measurements. The pre- and postoperative optical 3D surface scans were registered. A well-defined area in the malar region was used to determine the visible volume changes for each side separately. The mean accommodation vector that transforms the preoperative into the postoperative surface was assessed for each facial half separately. The soft-tissue-to-hard-tissue ratios between the incision superius and the labrale superius, the maximal parasagittal advancement of soft tissue, and the accommodation vectors were calculated.

RESULTS

A mean advancement of the incision superius of 5.3 +/- 2.1 mm was accompanied by a volume increase of 5.2 +/- 4.1 cm(3) in the right malar-midfacial region and 4.6 +/- 4.7 cm(3) on the left side, respectively, revealing a symmetrical volume change (p = 0.370). The soft-tissue-to-hard-tissue ratios were 80 +/- 94% for labrale superius and incision superius, 56 +/- 79% (right) and 51 +/- 56% (left) for accommodation vector and incision superius and 97 +/- 79% (right) and 98 +/- 89% (left) for maximal parasagittal advancement of soft tissue and incision superius.

DISCUSSION

The determination of volume changes and accompanying accommodation vectors complete the cephalometric analysis during the follow-up of patients undergoing LeFort I osteotomy. The data show that maxillary advancement leads to a more pronounced shifting of the soft tissues in the malar-midfacial area than of the upper lip. The new parameters will help to assess normative soft tissue data based on 3D imaging with a view to an improved three-dimensional prediction of the operative outcome of orthognathic surgery away from the midline.

[Anatomy of locating the internal auditory canal through the middle fossa approach with the assistance of high resolution CT]

OBJECTIVE

To evaluate the feasibility of localizing the internal auditory canal (IAC) and the facial nerve through the root of the zygoma, foramen spinosum and the head of the malleus in middle fossa approach with the assistance of high resolution computerized tomography (HRCT).

METHODS

Eighteen human cadaveric temporal bones were scanned and measured by HRCT. Cadaver specimen were divided into two groups. Group A was studied first through a middle fossa approach to find out the relationship between the HRCT measurements and the anatomic measurements. Then 4 whole human cadaveric heads (8 temporal bones) of group B were dissected using a HRCT oriented middle fossa approach to localize IAC with the root of the zygoma, foramen spinosum and the head of the malleus as landmarks. The two measurement methods were analysed with the Paired-Sample T test, and the difference was thought to be statistical significant when P < 0.05.

RESULTS

In Group A, there were no statistical significant differences between the CT measurements and the anatomic measurements from the head of the malleus to other important anatomic structures. In group B, the operation was guided with CT measurements: the distance between the head of the malleus and the root of the zygoma, and the distance between the head of the malleus and foramen spinosum. Within the range 1.5 mm to 3.7 mm, the head of malleus was correctly localized. In seven out of the eight cases, the root of the zygoma, the head of the malleus and the internal auditory canal were in a straight line, whereas, in one case, there was an angle of 15 degrees between the root of zygoma -head of malleus line and head of malleus -internal auditory canal line.

CONCLUSIONS

HRCT would provide more information on the distance relationship between the head of malleus and the root of the zygoma, foramen spinosum and the internal auditory canal. The head of the malleus could be localized through the root of the zygoma and foramen spinosum with HRCT and therefore the IAC could be exposed with the head of the malleus as a landmark in middle fossa approach when other landmarks were not recognizable.

Osteoid osteoma of the zygoma: report of an unusual case

BACKGROUND

Osteoid osteoma is a benign tumor of bone characterized by pain, usually occurring at night, that shows a dramatic response to aspirin. The literature contains reports of only a few cases in the head and neck region.

CASE DESCRIPTION

The authors present an unusual case of an osteoid osteoma of the craniofacial bones. The patient sought an evaluation of pain in the area of the right zygoma. One of the authors, an oral and maxillofacial surgeon, noted a small area of swelling. The patient underwent radiographic, computed tomographic and nuclear medicine studies. On the basis of the images and the biopsy report, the authors made a diagnosis of osteoid osteoma. In this article, they describe the treatment of and new modalities of therapy for this condition.

CLINICAL IMPLICATIONS

The general dentist should be aware of any lesion that is not common. If the generalist has any doubt about the nature or management of an unusual oral lesion, referral to appropriate specialists is mandatory.

[The finite element study on zygomatic injury by impact in child]

OBJECTIVE

The purpose of this study was to establish the constructive of craniofacial suture in the three-dimensional finite element model of craniofacial complex in child, to analyse the response procedure of the zygomatic impact, to explore the biomechanics characteristic of the children craniofacial trauma.

METHODS

A 7-year-old female was adopted for study The complex cranial geometry was measured from a series of two-dimensional CT images. The multi-lay spiral CT scans were transformed with a self-developed preprocessor into a finite element mesh. The craniofacial sutures were constructed through the MSC Patran program. Identical impact and boundary conditions were used for the zygomatic impact simulations.

RESULTS

It has been shown that the finite element model (FEM) exhibited fine morphological and mechanical comparability. The higher stress was showed in the zygomatic regions and atlas occipital articular in 3d FEM. The maximum von Mises stress was found at the zygomatic regions and atlas occipital articular.

CONCLUSION

The concentrations of shear stress and tension stress in the suture and articular would increase the risk of injury in this area. But the conduction of the stress might be weakening in the suture of child skull.

The Effects of Masseter Muscle Paralysis on Facial Bone Growth

BACKGROUND

Understanding the effects of muscle function on facial bone growth may help us treat children with facial anomalies. Facial bone growth is known to be a result of both genetic and epigenetic influences. One of the main epigenetic factors controlling growth is thought to be muscle action. The purpose of this study was to establish a model of single facial muscle paralysis and to identify the effects masseter muscle paralysis has on mandible and zygoma growth.

METHODS

Twenty New Zealand white rabbits were divided into control, paralysis, and sham groups. Masseter muscle paralysis was achieved with botulinum toxin A (BTX). Computed tomographic and single-photon emission computed tomography (SPECT) scans and cephalometric measurements were performed. Masseter weights and mandible and zygoma volumes, shapes, and metabolism were measured.

RESULTS

Eighteen animals completed the study. Significant decreases in zygoma and mandible volumes with minimal changes in shape were seen on the paralyzed sides. SPECT showed a decrease in bone production in both zygomas and mandibles on the paralyzed sides.

CONCLUSIONS

An animal model has been created in which the effects of single muscle paralysis on bone growth can be studied. Masseter muscle function may be responsible in maintaining mandible and zygoma volume by controlling bone production. Masseter function alone has less influence on mandible and zygoma shape.

A computed tomographic image study on the thickness of the infrazygomatic crest of the maxilla and its clinical implications for miniscrew insertion

INTRODUCTION

The purpose of this study was to measure the thickness of the infrazygomatic (IZ) crest above the maxillary first molar at different angles and positions to the maxillary occlusal plane. These measurements were then used to derive clinical implications and guidance for inserting miniscrews in the IZ crest without injuring the mesiobuccal root of the maxillary first molar.

METHODS

Computed tomographic images of 16 adults were used. For each subject, on the coronal slice of the computed tomographic image containing the IZ crest and mesiobuccal root of the maxillary first molar, the IZ crest thickness and the miniscrew insertion position were measured by postulating that the miniscrew would be inserted at each 5 degrees increment from 40 degrees to 75 degrees to the maxillary occlusal plane.

RESULTS

The IZ crest thickness above the maxillary first molar ranged from 5.2 +/- 1.1 mm to 8.8 +/- 2.3 mm, measured at 40 degrees to 75 degrees to the maxillary occlusal plane and 13 to 17 mm above the maxillary occlusal plane.

CONCLUSIONS

By adopting 6 mm as the minimal IZ crest thickness for sustaining a miniscrew well throughout treatment and avoiding injury to the mesiobuccal root of the maxillary first molar, the clinical implication for miniscrew placement in the IZ crest of an adult is to insert it 14 to 16 mm above the maxillary occlusal plane and the maxillary first molar at an angle of 55 degrees to 70 degrees to the maxillary occlusal plane.

Length determination of zygomatic implants using tridimensional computed tomography

Considering the potential of tridimensional computed tomography (3D-CT) as a predictor of real bone dimensions, nine dried human skulls with maxillary edentulism were evaluated using images obtained by 3D-CT, prior to the installation of zygomatic implants, in order to obtain the measurements of the implants. In the analysis of correlation between the two 3D-CT examiners, a 75% agreement was found, and no correlation was found between them and the surgical measurement. The worst result was the surgical one, possibly because an inaccurate probe was used. Based on the obtained data, we concluded that the probe used is inaccurate, suggesting that the surgical probe be changed in its measurement scale. Agreement between surgeon and radiologist could possibly be obtained by using insertion guides, since what might have possibly caused the discrepancy in the results is the fact that the 3D-CT examiners and the surgeon used different implant insertion points. It is also possible that a larger sample might produce a more accurate evaluation, thus improving the results.

Nonsurgical rapid maxillary expansion effects on craniofacial structures in young adult females. A bone scintigraphy study

OBJECTIVE

To evaluate the skeletal effects of nonsurgical rapid maxillary expansion (RME) on craniofacial structures with bone scintigraphy in young adult female subjects.

MATERIALS AND METHODS

The material of the present study consists of scintigraphic records taken from 17 early adult females treated with RME. All patients had a bilateral posterior crossbite, transverse maxillary deficiency, deep palatal vault, and dental crowding at the beginning of the treatment. The age range of the patients was 16.1 to 18.8 years, and the mean age was 17.3 +/- 0.86 years. Bone scintigraphy records were obtained before RME (T1), during the splitting of the midpalatal suture (T2), and after the end of active widening period (T3). Repeated measure analysis of variance was used to assess the differences between the periods. In addition, Bonferroni multiple comparison tests were applied to the measurements at which F values were found to be statistically significant.

RESULTS

According to the statistical analysis, significant activity changes were found in all regions studied and in all slices. The metabolic activity in all regions showed significant increases up to the separation of the midpalatal suture (T1-T2), whereas the metabolic activity exhibited a remarkable decrease (T2-T3) after the opening of the midpalatal suture.

CONCLUSIONS

Scintigraphic records revealed an increase in the regions of interest scores during RME in all regions and all slices. Therefore, it can be speculated that RME has had not only dental effects but also skeletal effects on young adult patients.

Primary intraosseous hemangioma of the orbit: an unusual presentation of an uncommon tumor

CASE REPORT

An asymptomatic patient was referred for assessment of an intraocular amelanotic mass in her left eye. Examination showed a mass effect in the inferior location at the 5 o'clock position. This abnormality was defined with ultrasound biomicroscopy and standard ultrasound, but because the appearance was not typical of a melanoma or other choroidal infiltrate, magnetic resonance images and computed tomograms of the orbits were obtained, identifying an extraocular mass arising from the zygomatic rim. Results of a biopsy reported an intraosseous hemangioma.

COMMENTS

The diagnosis of intraosseous hemangioma, because of its low incidence and unusual manner of presentation, can be challenging. Computed tomography and biopsy are helpful in making a definitive diagnosis.