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PubMed2006

Material properties of the dentate maxilla.

The aim of this study was to determine regional variability of material properties in the dentate maxilla. Cortical samples were removed from 15 sites of 15 adult dentate fresh-frozen maxillas. Cortical thickness, density, elastic properties, and the direction of greatest stiffness were obtained. Results showed that cortical bone in the alveolar region tended to be thicker, less dense, and less stiff. Cortical bone from the body of the maxilla was thinner, denser, and stiffer. Palatal cortical bone was intermediate in some features but overall was more similar to cortical bone from the alveolar region. The principal axes of stiffness varied regionally. The regions with the greatest consistency were the alveolar area and the frontomaxillary pillar, where the grain of the cortical bone was aligned vertically from the incisors to the medial external aspect of the orbit. Elastic properties in the human maxilla, especially the orientation of the principal axes of stiffness, were more variable than in the mandible. Incorporation of these properties into finite-element models should improve their accuracy and reliability.

Aged↗

PubMed1999

[Augmentation of the extremely atrophied maxilla and mandible by autologous calvarial bone transplantation].

Rehabilitation in patients with severe alveolar ridge atrophy of the maxilla or mandible is problematic and can often only be achieved by long-term treatment. In most cases, autologous bone grafting with iliac crest bone has been used to augment severely atrophied upper jaws. In our experience, iliac bone grafts are less useful, since iliac bone appears to be of inferior quality; in elderly osteoporotic women, the bone is soft, indentable, and of poor osteogenic potency. In our department, we have been using only autologous calvarial bone grafts for augmentation of alveolar ridge atrophy since 1993. The bone is removed from the outer table of the skull only, trimmed to the alveolar ridge, und fixed with titanium lag scews. The skull defect created is covered with crushed bone or a titanium mesh to avoid aesthetic problems. Insertion of dental implants follows after a healing period of the bone grafts of 5-6 months. A total of 63 patients underwent calvarial split-graft augmentation; augmentation of the maxilla and mandible was carried out in 15 of these patients, of the maxilla only in eight, and of the mandible only in 40. The investigations 1 year later showed a resorption rate of approximately 10%. This is lower than when using iliac bone grafting. The resorption results were stable between 6 and 12 months after augmentation. Using dental implants (12 patients with 32 implants), the resorption rate was low and constant. We have never seen total loss of bone grafts or intracranial complications. All patients were pleased with the treatment. In our opinion, severe alveolar atrophy of the maxilla or mandible should be compensated for by augmentation with autologous calvarial bone grafts to obtain good long-term results.

Adult↗

PubMed1999

[The maxilla--a poor implant site?].

In the maxilla, it is sometimes necessary to use implants to achieve a good prosthetic result. However, an increased failure rate of maxillary implants seems to be a common clinical experience. This experience was investigated in a retrospective statistical analysis. In a retrospective study of 665 patients between 1987 and 1997, 2484 implants were examined. The implants in the upper jaw were compared to those in the lower jaw. Implants with and without autogenous bone grafts and fixtures in patients with alveolar ridge atrophy, tumor, or trauma were explored. In particular, the data obtained from the orthopantomograms after completion of the prosthetic superstructures were controlled for peri-implantary bone loss evaluation. A total of 40% of the fixtures were placed in the maxilla, and 30% of these implants were combined with a local or an iliac bone graft. Out of 2484 implants, 207 were lost, largely during the healing period. The failure rates in the groups of patients with alveolar ridge atrophy, tumor, and trauma were between 6 and 27.5%, and the differences between these groups were higher than the difference between the upper and the lower jaw. Especially in the maxilla and after osteoplasty, horizontal peri-implantary bone loss was increased, with some cases of dramatic bone loss and decrease of the osseous integration of the fixtures. There was no statistic evidence of a significantly higher failure rate in the upper jaw than in the lower jaw. However, besides the rate of implant loss, additional markers should also be considered for adequate evaluation of implant prognosis in the maxilla.

Alveolar Bone Loss↗

PubMed2000

[Callus distraction of the maxilla. Supplement or alternative to advancement osteotomy].

Total or partial relapses after conventional surgical advancement of the maxilla following Le Fort I osteotomy in CLP patients are frequent and major complications. The aim of this investigation was to find out whether the technique of distraction osteogenesis in these patients shows more stability and whether maxillary distraction is able to replace conventional advancement. Maxillary distraction was performed in 12 patients. In two cases, a Delaire mask was used to bring the maxilla forward, ten patients were treated with the extraoral distraction device designed by Polley. In all patients, planned advancement of the maxilla could be achieved; one partial relapse occurred. The results indicate that distraction osteogenesis offers the possibility of advancement of the maxilla with the required stability. The technique presents a major improvement which is achieved with a relatively minor surgical procedure.

Adolescent↗

PubMed1980

Surgical superior repositioning of the maxilla: what to do with the mandible?

During superior repositioning of the maxilla (SRM), the mandible autorotates forward and upward at pogonion, with the condyle as the center of rotation. Thus, in each instance when planning surgical superior repositioning of the maxilla one must decide, on the basis of esthetics and cephalometric prediction criteria, the magnitude of autorotation and the contribution of this rotation toward the desired occlusal and esthetic result. In many instances the maxilla can be moved somewhat posteriorly or anteriorly, and thus simultaneous mandibular surgery is not required to achieve the desired result. In some cases, however, simultaneous mandibular advancement or set-back is required to achieve the desired occlusal and esthetic result. This article discusses the specifics of making the decision regarding what to do with the mandible when superiorly repositioning the maxilla.

Adolescent↗

PubMed1988

Simultaneous superior repositioning of the maxilla and mandibular advancement. A report on stability.

Fifty-three patients who underwent simultaneous surgical superior repositioning of the maxilla and mandibular advancement were studied cephalometrically and clinically for at least 1 year after surgery (mean 2.4 years). The pattern of change for the maxilla and the percentage of patients who had 2 mm or more movement of landmarks were consistent with that observed following isolated superior repositioning of the maxilla. Although changes similar to those observed with isolated mandibular movement occurred, because the changes in the maxilla also affected the mandible, a greater percentage of patients experienced postsurgical movement of the mandible in this group than in those undergoing mandibular advancement alone. Clinically, satisfactory or better results were observed in 42 (79%) patients at their longest follow-up examination. The only significant variable associated with clinical outcome was the presence (presurgically) of an open bite (p less than 0.04) in 10 of 11 patients with poor clinical results. There was no statistically significant relationship between cephalometric stability and clinical outcome in this series of patients.

Adolescent↗

PubMed2006

Long-term clinical and radiological outcomes of surgical management of central giant cell granuloma of the maxilla.

The aim of this study was to report the results of long-term clinical and radiological follow up of the surgical management of central giant cell granuloma of the maxilla. A retrospective analysis was conducted on 12 patients--5 male and 7 female whose ages ranged from 9 to 41 years, with central giant cell granuloma of the maxilla treated between 1991 and 2000. The anterior maxilla was involved in five cases, seven cases were in the posterior region, and none crossed the midline. Four patients were asymptomatic and eight patients presented with pain, mobility of teeth, and rapidly enlarging facial swelling. Radiographically, all lesions were radiolucent; 58.3% were unilocular, and the borders were well-defined in 33.3%. Roots were commonly displaced by the lesion, but no root resorption was observed. Cortical perforation was seen clinically and on CT scan in four patients. All cases were treated with thorough curettage until healthy bone was encountered. In cases with cortical perforation the affected buccal and/or palatal mucosa was excised. When the maxillary sinus was affected or the lesion was bulging into the nose, the nasal mucosa was also removed. All patients were reviewed annually for a follow-up period of 2-9 years; the condition recurred in two patients. It is concluded that thorough curettage is a satisfactory method for the treatment of non-aggressive and aggressive central giant cell granuloma of the maxilla, with a low recurrence rate and favorable postoperative outcome.

Adolescent↗

PubMed2005

Biologic mechanical advantages of 3 different cranial bone grafting techniques for implant reconstruction of the atrophic maxilla.

PURPOSE: The purpose of this study was to test the mechanical capacities of 3 different bone grafting techniques in the atrophic maxilla when co-stabilized with dental implants. Reconstruction of the atrophic maxilla is a difficult clinical challenge and implants cannot be placed without adequate bone. METHODS: The biomechanical performance of 3 different grafting techniques was evaluated in vitro using a maxillary model, cadaveric cranial bone blocks, and dental implants. A maxillary model fabricated from polyurethane (sawbone) was selected as a substrate for this study because of consistency in shape, size, and mechanical properties. This anatomic model was more consistent than different cadaveric maxilla, where significant variation was found to exist among atrophic specimens. Cadaveric cranial bone graft blocks were secured to the model maxilla (sandwich, ridge only, and sinus inlay) with a dental implant. The strength of the implant/bone graft complex was tested to failure in an Instron machine (Instron Inc, Canton, MA). RESULTS: The 3 bone grafting methods showed significantly different deformation and strength characteristics. The sandwich technique enhanced resistance to deformation under higher imposed loads. The location of the graft influenced the overall mechanical performance (eg, the ridge onlay) and showed a significantly higher resistance to compressive loads applied toward the alveolar ridge (mastication force). CONCLUSION: The ridge onlay grafting procedures created a higher biomechanical tolerance to imposed load than the sinus grafting (sinus inlay). Sinus grafting, although successful, was not the most ideal location for immediate mechanical loading resistance when compared with ridge augmentation in this in vitro model.

Alveolar Bone Loss↗

PubMed2000

Treatment outcomes of fixed or removable implant-supported prostheses in the edentulous maxilla. Part I: patients' assessments.

STATEMENT OF PROBLEM: Distinct clinical parameters determine whether fixed or removable implant-supported prostheses are indicated to restore the edentulous maxilla. However, there is a strong belief that fixed implant prostheses meet with greater patient acceptance and satisfaction, but this may differ from the patients' perceptions, their psychological responses to treatment, and their assessments of the treatment outcome. PURPOSE: This prospective clinical study compared the treatment outcomes of fixed and removable implant-supported restorations in the edentulous maxilla with the main emphasis on the patient's point of view. MATERIAL AND METHODS: Twenty patients who requested an implant-supported superstructure to restore the edentulous maxilla were asked to complete a questionnaire measuring their satisfaction with the present situation and the psychologic impact of their oral health status with their responses marked on a Visual Analog Scale (VAS). Ten patients were treated with a fixed, screw-retained implant prosthesis (group 1), and 10 were treated with a removable, implant-supported and bar-retained overdenture (group 2). Six months after prosthetic rehabilitation, patients were again given the questionnaire to assess their psychologic well-being and satisfaction with the implant-supported restoration. RESULTS: Both prosthesis designs were associated with significant improvements in comfort and retention, function, esthetics and appearance, taste, speech, and self-esteem. No difference was found between the 2 groups with respect to how the patients assessed the implant therapy. However, the results indicated that patients in group 2 experienced greater differences between pretreatment and posttreatment scores for the parameters esthetics, taste, and speech. Treatment costs per unit were significantly higher in group 1 than in group 2. CONCLUSION: Patients in groups 1 and 2 were similarly satisfied with their implant-supported prostheses in the edentulous maxilla with regard to their well-being and the cost-utility, irrespective of whether the restoration was fixed or removable.

Adult↗

PubMed1986

Horse-shoe sandwich osteotomy of the edentulous maxilla as a preprosthetic procedure.

A preprosthetic procedure for treatment of severe atrophy of the maxilla is reported. By means of the horse-shoe sandwich osteotomy of the edentulous maxilla with interposition of iliac crest or ribs in combination with a modified submucous vestibuloplasty there is the possibility of increasing the vestibular and palatal height and improving the mucosal contour in one surgical session. The method, which is described in details, avoids the disadvantages of the earlier operation methods of direct osseous augmentation and the Le Fort-I-osteotomy of the edentulous maxilla. The satisfactory results of 15 operated cases in the observation period of 3 to 15 months are reported. There is only little bone resorption. The horse-shoe sandwich osteotomy might therefore be the method of choice in cases of extreme atrophy of the maxilla.

Alveolar Ridge Augmentation↗

PubMed1995

Surgically assisted rapid orthodontic lengthening of the maxilla in primates--a pilot study.

Orthodontic and surgical treatment of patients with maxillary retrusion and/or midface hypoplasia is challenging. This study was designed to show that the maxilla can be successfully lengthened by surgical assisted rapid orthopedic movement, using the principles of distraction osteogenesis. Three experimental and three control adolescent cynomolgus primates were used in this study. Metallic markers were placed in the cranial base and the maxilla and cephalometric x-ray films were taken. An orthodontic appliance was constructed with a Glen-Ross screw (Dentaurum, Newtown, Pa.) oriented anteroposteriorly. Anterior supraapical osteotomies of the maxilla were carried out. Bilateral horizontal and interdental osteotomies were created between the first premolars and the canine; the anterior six tooth dental-osseo segment was completely mobilized in all animals. Beginning 1 week after surgery, the orthodontic appliance was opened a quarter turn every 2 days until the anterior segment was advanced by 4 mm in two animals and 6 mm in one animal. Animals were killed at 6, 8, and 12 weeks after completion of the maxillary orthopedic advancement. Computerized tomographic scans of the maxillae were completed, and the specimens were then prepared by routine histologic methods for examination by light microscopy. The computerized tomographic scans showed bone deposition in the osteotomy sites, which was confirmed by histologic observations. Since this technique demonstrated repair by bone rather than soft connective tissue in the osteotomy sites, this procedure could be a useful method of treating midface retrusion.

Animals↗

PubMed2002

Effect of calcium supplementation on bone dynamics of the maxilla, mandible and proximal tibia in experimental osteoporosis.

The effect of calcium supplementation on the bone dynamics in the hard palate of the molar region (maxilla), mandible and proximal tibia in experimental osteoporotic rats was examined. Ninety ovariectomized (OVX) and 45 sham-OVX Wistar female rats were used in this study. All the rats received surgical operation at 6 weeks of age. Ovariectomized rats were fed on a low calcium diet (0.02%) for 12 weeks post-operation, and then randomly divided into the two following groups. One group was fed on high calcium diet (2.30%) (OVX-HCa) and the other group was remained on the low calcium diet (OVX-LCa). Sham-OVX rats were fed on regular calcium diet (1.15%) during the experimental period (Sham-OVX). Histomorphological analysis was carried out from 12 to 32 weeks post-operation. On undecalcified thin section, bone volume, eroded surface, osteoid surface and bone formation rate were calculated for cortical bone of the maxilla, and for cancellous bone of the mandible and proximal tibia. In the OVX-LCa group, compared with the Sham-OVX group, decrease of the bone volume and increase of the bone resorption and formation parameters were detected throughout the observation periods. In the OVX-HCa group, compared with the OVX-LCa group, increase of the bone volume and temporarily increased parameters of bone formation at 1 week after feeding on high calcium diet were observed in the maxilla, but these changes were not observed in the mandible and proximal tibia. Moreover, the bone resorption and formation parameters in the maxilla, mandible and proximal tibia in the OVX-HCa group became equivalent to the Sham-OVX levels with the passage of time.

Analysis of Variance↗

PubMed2003

A biologic model for assessment of osseous strain patterns and plating systems in the human maxilla.

PURPOSE: This study was conducted to examine a biomechanical model and to help answer fundamental questions that relate to rigid plate fixation in the maxilla. Specifically, we sought to elucidate the principal strain patterns generated in the maxilla secondary to masticatory forces as well as the amount of permanent deformational changes incurred due to these loading forces. MATERIALS AND METHODS: Cadaveric heads with the mandible removed were defleshed and placed in a 2-part testing rig to hold and position the skull for testing in a standard material testing system. Rosette strain gages were attached at predefined points on the skull, and an Instron machine was used to load the skull through the loading port on the tray. A Le Fort I osteotomy was then performed on the skull, and a Walter Lorenz Ultra-Micro plating system was applied by a surgeon to reconnect the upper jaw. A 2-mm gap was left at the line of the osteotomy, and a transducer was attached to measure closure of the gap. Again the skull was loaded with the Instron (Canton, MA) machine. RESULTS: The results indicate a linear relationship exists with both maximum (tensile) and minimum (compressive) strain patterns relative to incremental load placement on the intact maxilla. The strain patterns after the Le Fort I osteotomy and plating were different and less linear. The differential variable reluctance transducer data showed a low rate of closure or transient increase in the gap at low loads (0 to 15 kilopond [kp] range) and a steeper slope of closure during high loads (15 to 60 kp range). It is also evident that axial loading forces cause permanent deformation and failure of osseous plating systems predominantly through bending. CONCLUSIONS: This model provides a foundation of knowledge regarding biomechanical strains in the maxilla subjected to static compressive loads in the force range of mastication. In addition, it serves as a comparative reference to assess rigidity of various craniofacial plating systems and to validate proposed standardized synthetic models. With the advent of increasingly precise surgery and new plating systems, this model can be used to help guide placement and design of plating systems; thereby allowing for ideal stabilization and optimizing surgical outcome.

Aged↗

PubMed1989

Effects of sagittal expansion in noncleft macerated human maxillae.

The effects of sagittal expansion with a cemented expansion appliance were studied in nine noncleft macerated human maxillae ranging from 1-10 years. It was found that opening of the premaxillo-maxillary suture did occur in the youngest maxilla. Movement of the incisor roots through the labial cortical plate was observed in seven specimens. In one maxilla, dislocation of the maxillary tuberosity occurred. The results of this investigation suggest that it seems questionable that sagittal expansion using cemented appliances in noncleft human maxillae will in most instances result in breaking the ossification of the premaxillo-maxillary suture together with the interlocking serrations.

Child↗

PubMed1999

Effects of ovariectomy on bone morphology in maxillae of mature rats.

Postmenopausal oestrogen deficiency results in bone loss (osteoporosis) in humans and experimental animals. The loss of trabecular bone in the ovariectomized (OVX) rat provides a useful experimental model of post-menopausal osteoporosis. At 5 months after ovariectomy of 3-month-old female rats, the mid and distal femurs and maxillae were dissected and processed for quantitative backscattered electron microscopic examinations. Histomorphometric analysis of femurs in OVX rats showed significant loss in metaphyseal trabecular bone areas compared with sham-operated controls; no significant bone loss was observed in the cortical bone areas of mid-diaphyses in OVX rats. Net bone areas in the maxillae of OVX rats was similar to that of sham-operated controls. Bone structure of maxillae in OVX rats was also similar to that in controls. Our results suggest that, in this animal model of osteoporosis, prominent bone loss occurs mainly in the bone areas formed by endochondral ossification such as distal femurs, but those areas formed by intramembranous ossification such as mid-femurs and maxillae sustained less effects by OVX.

Animals↗

PubMed2000

Treatment of micrognathia with edentulous maxilla by sagittal split mandibular osteotomy and a subperiosteal implant immobilized with transmaxillary screws.

Micrognathia complicated by edentulous maxilla was treated by performing sagittal-split mandibular osteotomy and immobilizing a subperiosteal implant using transmaxillary screws. The patient was a 42-year-old man who had a birdlike facial deformity caused by significant hypoplasia of the mandible. He also demonstrated significant malocclusion attributable to micrognathia and edentulous maxilla caused by resorption of the alveolar bone. These conditions impaired his mastication and articulation, making it impossible for him to eat regular food or carry out normal conversation. A subperiosteal implant was placed on the edentulous maxilla, and was rigidly immobilized to the maxilla using five transmaxillary screws. A prosthesis was then attached to the implant, and by using the implant as the point of reference and the anchor, the mandible was moved forward by sagittal-split mandibular osteotomy. Intermaxillary fixation was subsequently performed. The postoperative course has been favorable, and his facial complexion has improved significantly. One and a half years after his surgery, there has been no sign of complications or malocclusion caused by mandibular retraction. He is now able to eat regular food and speak normally.

Adult↗

PubMed2005

Congenital fusion of the maxilla and mandible.

Congenital fusion of the maxilla and mandible (syngnathia) is rare and can present in a wide range of severity from single mucosal bands (synechiae) to complete bony fusion (synostosis). Congenital synostosis of the mandible and maxilla is even less common than synechiae, with only 25 cases reported in the literature. Most of them presented as an incomplete, unilateral fusion. A 4-year-old boy was referred to the authors' emergency unit with asphyxia after vomiting. The authors found the child could not open his mouth. His upper and lower jaws were fused, with only a 2- to 3-mm gap in the anterior part. X-rays and computed tomography scans showed that there was a bony fusion of the ramus of the mandible to the zygomatic complex and the posterior part of the maxilla. In addition, there was significant mandible hypoplasia. After performing an osteotomy (to treat the fusion between the bilateral ramus mandible, maxilla, and zygoma), the authors performed a temporomandibular joint reconstruction using a silicon block. After the completion of these procedures, they observed that the mouth could be opened 32 mm. After 2 years of mandibular lengthening performed with an external distracter, the patient's facial appearance and occlusion became more acceptable. An extremely rare case is described, and the existing literature is reviewed.

Child, Preschool↗

PubMed2005

Patterns of innervation of the anterior maxilla: a cadaver study with relevance to canine fossa puncture of the maxillary sinus.

OBJECTIVES/HYPOTHESIS: Complications from canine fossa puncture of the maxillary sinus are caused by damage to the anterior superior alveolar nerve (ASAN) and the middle superior alveolar nerve (MSAN). The aim of this study was to elucidate the pattern of ASAN and MSAN within the anterior maxilla and to secondly determine suitable surgical landmarks to aid in accurately localizing the area of the canine fossa least likely to produce complications when a trocar is passed into the maxillary sinus. METHODS: Anatomic dissection of the anterior face of the maxilla from 20 cadaver heads was performed. The pattern and presence of the ASAN and MSAN was identified on each side and tabulated. Landmarks for the safest entry point for canine fossa puncture were determined, and each side had a puncture placed using these landmarks. Any disruption of nerves was noted. RESULTS: Multiple differing patterns of ASAN were identified. The ASAN emerged from its foramen as a single trunk in 30 (75%) sides and in a double trunk in 10 (25%). In 24 (60%), single or multiple branches from the ASAN trunks were identified. A MSAN was identified in 9 (23%) maxillae. The safest entry point for a canine fossa puncture was where a vertical line drawn through the mid-pupillary line was bisected by a horizontal line drawn through the floor of the pyriform aperture. CONCLUSIONS: There is significant variation in the pattern of ASAN and MSAN within the anterior face of the maxilla. By using the newly described landmarks when performing a canine fossa puncture, there is reduced risk of damage to these nerves and provides a reliable point to enter the maxillary sinus.

Cadaver↗