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PubMed1997

Ameloblastic fibrosarcoma arising de novo in the maxilla.

An ameloblastic fibrosarcoma (AFS) arising in the maxilla of a 14-year-old male is described. The tumor originated from the alveolar bone of the right maxilla with no apparent history of pre-existing lesion. Histologically, the lesion was composed of benign-appearing epithelial islands and strands scattered within an exceedingly cellular mass of mesenchymal tissue comprising a large number of stellate-and spindle-shaped fibroblast-like cells with marked pleomorphism. Occasional cementum-like calcification was also noted. Immunohistochemically, the neoplastic mesenchymal cells were positive only for vimentin, whereas the ameloblast-like epithelial component showed a distinctly positive reaction for wide-spectrum keratin and squamous cytokeratin. Clinicopathological features of the current case, as well as previously reported examples of AFS originating from the maxilla, are briefly discussed.

Adolescent↗
PubMed1995

Anatomic site evaluation of edentulous maxillae for dental implant placement.

PURPOSE: This study evaluated 17 edentulous cadavers for bone quantity and quality of the alveolar process of the maxilla for the purpose of dental implant placement. MATERIALS AND METHODS: The maxillary arch was divided into four anatomically defined regions for measurements of bone quantity. Bone quality was assessed histologically and described by trabecular bone patterns and tissue composition. RESULTS: Average bone height with a minimum thickness of 4 mm was as follows: region 1, 12.1 +/- 4.9 mm; region 2, 14.1 +/- 7.2 mm; region 3, 6.1 +/- 2.8 mm; and region 4, 8.5 +/- 2.2 mm. Histological evaluation showed increased trabeculation and thicker cortex in the maxillary anterior area, regions 1 and 2. Region 3, the floor of the maxillary sinus area, had the least amount of bone; however, the quality of bone was superior to that of region 4, the maxillary tuberosity area. Trabecular distance or marrow spaces ranged from 40 microns to 2 mm with larger spaces associated with the posterior maxilla. CONCLUSIONS: Maxillary tuberosity is the least desirable site for the placement of implants in the maxilla. The area corresponding to the first and second molars had the least bone thickness. All measures of bone preservation need to be considered, especially in this area.

Aged↗
PubMed2004

Long-term implant survival in the grafted maxilla: results of a 12-year retrospective study.

OBJECTIVE: The aim of this study was to determine the long-term outcome of implant insertion in the augmented severely atrophied maxilla. STUDY DESIGN: Three hundred and twenty-four implants were inserted in 35 patients (eight males, 27 females, average age 57.6 years) in extremely atrophied maxillae after osteotomy and interposition of iliac crest bone. One hundred implants were installed in 12 patients simultaneously with the osteotomy and grafting; 224 implants were placed in 23 patients in a second procedure 6-12 months later. Implant parameters like osseointegration and peri-implant bone loss; peri-implant tissue parameters like bleeding, gingival and plaque index; and patients' satisfaction were evaluated. RESULTS: Of 324 implants, 29 (8.9%) were lost during the entire follow-up: 14 in six patients of the one-step and 15 in 11 patients of the two-step group. The overall input-output survival in 141.1 months was 91.1%. The overall 2-year failure-free fraction of implants was 95.5%; the 5-year failure-free fraction was 89.3%. In the one-step group, the 2 (5)-year failure-free fraction was 95.9% (86.9%), and in the two-step group 95% (91.3%) (log-rank test P=0.57). Marginal peri-implant bone loss was 1.7+/-1.3 mm mesial and 1.8+/-1.3 mm distal. CONCLUSION: Implant insertion after osteotomy and iliac bone grafting is a reliable operation method for the dental rehabilitation of the severely atrophied maxilla showing good long-term results.

Atrophy↗
PubMed1985

Blood flow in maxilla and mandible of normal and atherosclerotic rhesus monkeys.

Atherosclerotic vascular disease affects many individuals, particularly in an elderly population. This study examined alterations in the vasculature and blood flow in the maxilla and mandible in rhesus monkeys fed an atherogenic (high fat) diet. No significant difference was found in blood flow between different regions of the bone (anterior mandible, posterior mandible and maxilla) in animals on either a normal or a high fat diet but overall blood flow in the monkeys on the atherogenic diet was significantly lower (p less than 0.001) than in the control group. Histologic examination of tissue from the animals fed an atherogenic diet revealed minimal changes within the intrabony vasculature and measurements of these vessels showed no significant difference in the percentage of tissue occupied by vessel lumina or in average wall thickness between the groups of animals. On the other hand, tissue from the tongue exhibited gross atherosclerotic vascular lesions and examination of the carotid arteries revealed not only intimal plaques but extensive calcification. It thus appears that the decreased flow measured in the maxilla and mandible may be related to the severely involved afferent vessels rather than to functional changes in the local vasculature.

Animals↗
PubMed2005

All-on-4 immediate-function concept with Brånemark System implants for completely edentulous maxillae: a 1-year retrospective clinical study.

BACKGROUND: Immediate implant function has become an accepted treatment modality for fixed restorations in totally edentulous mandibles, whereas experience from immediate function in the edentulous maxilla is limited. PURPOSE: The purpose of this study was to evaluate a protocol for immediate function (within 3 hours) of four implants (All-on-4, Nobel Biocare AB, Göteborg, Sweden) supporting a fixed prosthesis in the completely edentulous maxilla. MATERIALS AND METHODS: This retrospective clinical study included 32 patients with 128 immediately loaded implants (Brånemark System TiUnite, Nobel Biocare AB) supporting fixed complete-arch maxillary all-acrylic prostheses. A specially designed surgical guide was used to facilitate implant positioning and tilting of the posterior implants to achieve good bone anchorage and large interimplant distance for good prosthetic support. Follow-up examinations were performed at 6 and 12 months. Radiographic assessment of the marginal bone level was performed after 1 year in function. RESULTS: Three immediately loaded implants were lost in three patients, giving a 1-year cumulative survival rate of 97.6%. The marginal bone level was, on average, 0.9 mm (SD 1.0 mm) from the implant/abutment junction after 1 year. CONCLUSION: The high cumulative implant survival rate indicates that the immediate function concept for completely edentulous maxillae may be a viable concept.

Acrylic Resins↗
PubMed2005

Short implants in the severely resorbed maxilla: a 2-year retrospective clinical study.

BACKGROUND: Although the predictability of endosseous dental implants is well documented, the restoration of the posterior region of the maxilla remains a challenge. The placement of short implants is one therapeutic option that reduces the need for augmentation therapy. PURPOSE: The purpose of this retrospective study was to assess the survival rates of 6 to 8.5 mm-long implants in the severely resorbed maxilla following a surgical protocol for optimized initial implant stability. MATERIALS AND METHODS: The study included 85 patients with 96 short (6-8.5 mm) implants (Brånemark System, Nobel Biocare AB, Göteborg, Sweden) supporting single-tooth and partial reconstructions. The implants had a machined (54) or an oxidized (TiUnite, Nobel Biocare AB) (42) surface. A one-stage surgical protocol with delayed loading was used. The patients were followed for at least 2 years after loading (average follow-up period 37.6 months). The marginal bone resorption was assessed by radiographic readings. RESULTS: Five implants were lost during the first 9 months, and four implants were lost to follow-up. The cumulative survival rate was 94.6%. Four of the failed implants had a machined surface, and one had an oxidized surface. The mean marginal bone resorption after 2 years in function was 0.44 +/- 0.52 mm. CONCLUSION: This study demonstrates that the use of short implants may be considered for prosthetic rehabilitation of the severely resorbed maxilla as an alternative to more complicated surgical techniques.

Alveolar Bone Loss↗
PubMed2006

A prospective clinical study on titanium implants in the zygomatic arch for prosthetic rehabilitation of the atrophic edentulous maxilla with a follow-up of 6 months to 5 years.

BACKGROUND: Prosthetic rehabilitation with implant-supported prostheses in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, a rigid anchorage can also be achieved by using so-called zygomatic implants placed in the zygomatic arch in combination with regular implants placed in residual bone. PURPOSE: The aim of the present study was to report on the clinical outcome of using zygomatic and regular implants for prosthetic rehabilitation of the severely atrophic edentulous maxilla. MATERIALS AND METHODS: Sixty-nine consecutive patients with severe maxillary atrophy were, during a 5-year period, treated with a total of 69 fixed full-arch prostheses anchored on 435 implants. Of these, 131 were zygomatic implants and 304 were regular implants. Fifty-seven bridges were screw-retained and 12 were cemented. The screw-retained bridges were removed at the examination appointments and each implant was tested for mobility. In addition, the zygomatic implants were subjected to Periotest (Siemens AG, Bensheim, Germany) measurements. The patients had at the time of this report been followed for at least 6 months up to 5 years in loading. RESULTS: Two regular implants failed during the study period giving a cumulative survival rate of 99.0%. None of the zygomatic implants was removed. All patients received and maintained a fixed full-arch bridge during the study. Periotest measurements of zygomatic implants showed a decreased Periotest values value with time, indicating an increased stability. Three patients presented with sinusitis 14-27 months postoperatively, which could be resolved with antibiotics. Loosening of the zygomatic implant gold screws was recorded in nine patients. Fracture of one gold screw as well as the prosthesis occurred twice in one patient. Fracture of anterior prosthetic teeth was experienced in four patients. CONCLUSIONS: The results from the present study show that the use of zygomatic and regular implants represents a predictable alternative to bone grafting in the rehabilitation of the atrophic edentulous maxilla.

Adult↗
PubMed1977

The instantaneous transverse changes in the maxilla due to different points of force application.

The effects of different sites of an expansile force on the maxillae of three monkeys were studied. A lateral force of five pounds was delivered directly to four locations on each maxilla. Aluminum rods, rigidly attached to the teeth of each buccal segment, were photographed before and after each force application. The data indicated that the pattern of lateral maxillary displacement is related to the position of the lateral force in relation to the center of resistance of each maxilla.

Animals↗
PubMed2005

Rigid external distraction using skeletal anchorage to cleft maxilla united with alveolar bone grafting.

OBJECTIVE: Documentation of the application of maxillary distraction osteogenesis using rigid external distraction (RED) with skeletal anchorage combined with predistraction alveolar bone grafting (ABG) in cleft maxilla. DESIGN: Case report. PATIENT: A patient with numerous congenital missing teeth and severe maxillary deficiency related to complete bilateral cleft lip and palate with large alveolar bone defect. INTERVENTION: The patient received preoperative orthodontic treatment, predistraction ABG, and maxillary distraction osteogenesis using RED with skeletal anchorage. RESULTS: Predistraction ABG completely united the cleft maxilla. The united maxilla was successfully advanced by the RED system with skeletal anchorage, despite unsound dentition with numerous congenital missing teeth. CONCLUSION: The present study demonstrates that the combination of predistraction ABG and RED system with skeletal anchorage is effective for the treatment of severe maxillary deficiency related to complete bilateral cleft lip and palate with large bone defect and numerous congenital missing teeth.

Adolescent↗
PubMed1991

A histochemical study of the development of premaxilla and maxilla during secondary palate formation in the mouse embryo.

The development of premaxilla and maxilla in the mouse fetus during secondary palate formation from the 12th to the 16th days of gestation was histochemically assessed. To determine the developmental stages, a classification based on the morphogenesis of the limbs, or the "limb score" (LS) was employed. The stage of LS coincided with the gestational age from the 13th to the 15th days. Early on the 12th day, alkaline phosphatase (ALPase) activity was intense in the mesenchyme lateral to the incisor tooth bud and latero-inferior to the inferior orbital nerve. Subsequently, osteoblasts differentiated at these two sites. The ALPase positive area grew concomitantly with the nasal capsule, the molar tooth germ, and the closure of the secondary palate. The area of bone differentiation contoured the orbital nerve and extended to the rostral part of the secondary palate. At the LS stage -6 (13.52 days), ALPase activity was observed in the mesenchyme medial to, and also surrounding the molar tooth germ. The area of osteogenesis of the secondary palate spread along the medial side of the molar tooth germ, where the formation of the medial alveolar process of the maxilla was completed by the LS stage 3 (15.35 days). The ALPase positive area extended to the horizontal palatal shelves. By late on the 16th day, the palatal process was fully developed. In parallel, bone resorption began on the molar side of the alveolar process. Acid phosphatase and tartrate-resistant acid phosphatase activities (ACPase and TRACPase activity, respectively) revealed ACPase and TRACPase positive mononuclear cells around the molar tooth germ long before ossification occurred. Our results thus suggest an involvement of the incisor tooth bud and the infra-orbital nerve in the initial osteogenesis of the premaxilla and maxilla. Enzyme activities lead to the consideration that osteoclast precursors initiate differentiation around the molar tooth germ. Ostensibly, the mechanical force from the growth of the molar tooth would promote differentiation and activation of osteoclasts located on the alveolar process. Also, the LS classification would improve and simplify future studies of the development of the secondary palate.

Acid Phosphatase↗
PubMed1992

Radiologic findings of diseases involving the maxilla and mandible.

The purpose of this pictorial essay is to illustrate the radiologic appearances of diseases involving the maxilla and mandible. The high prevalence of dental disease results in inflammatory, infectious, and reactive processes that must be distinguished from more serious conditions with similar radiologic features. Because of their association with odontogenic tissues, lesions of the maxilla and mandible may have radiologic findings not seen in other bones. Furthermore, nonodontogenic cysts and tumors that occur elsewhere in the skeleton may exhibit unique radiologic characteristics when associated with teeth. This pictorial essay presents the radiologic characteristics of inflammatory lesions, developmental abnormalities, fibroosseous lesions, benign cysts and tumors, and malignant lesions of the maxilla and mandible.

Cysts↗
PubMed1999

Fixed implant rehabilitation of the edentulous maxilla: clinical guidelines and case reports. Part I.

Fixed implant reconstruction is one of the most challenging prosthetic treatment alternatives for the edentulous maxilla. Accurate diagnosis and treatment planning are essential to successful, predictable clinical results. Decisions concerning the placement of implants may have a lasting impact on the quality and prognosis of the final restoration. A series of clinical guidelines and considerations is presented with illustrative clinical treatment protocols of edentulous maxillae that vary in degrees of anatomical and prosthetic difficulty. This article addresses the fixed implant rehabilitation of edentulous maxillas with favorable anatomy and favorable arch position, favorable anatomy, and unfavorable arch position, and unfavorable anatomy and favorable arch position.

Adult↗
PubMedDate not supplied

Brånemark system implants in the posterior maxilla: clinical study of 660 implants followed for 5 to 12 years.

Originally, osseointegrated implants were used principally in the anterior region of the mandible and maxilla, but use in the posterior segments of both arches is common today. The long-term success of implants placed in the posterior region, an environment of stronger forces and poorer bone quality, has not been thoroughly reviewed. The purpose of the present study was to review a large series of Brånemark System implants placed in posterior maxillae (660 implants in 202 patients) that have been restored with fixed partial ceramometal restorations and followed for as long as 12 years after loading. Thirteen of the implants (2%) failed between placement and loading, 12 implants were lost between loading and the end of the first year, and 10 failed thereafter, 2 as the result of fractures at 3 and 4 years. The cumulative success rate is therefore 94.4% at 5 to 6 years and 93.4% after 10 years. The quality and quantity of bone appeared to have little influence on the success rate. Surgical techniques are particularly important to the success of osseointegrated implants placed in the posterior maxilla. With careful surgical planning and execution, a success rate of approximately 95% at 5 years can be achieved.

Adolescent↗
PubMedDate not supplied

A prospective human clinical trial of Endopore dental implants in restoring the partially edentulous maxilla using fixed prostheses.

This is the first report of a group of 50 partially edentulous patients who received a total of 151 Endopore dental implants in the maxilla. A mean implant length of 8.7 mm was used, and 76.8% of implants were placed in the posterior maxilla. At re-entry, all implants appeared to be osseointegrated and were used to support fixed prostheses. Approximately half of the crowns (57%) in these prostheses were splinted to one another, while the remainder (43%) were not. At the time of this report, the mean functional time was 34.6 months and the cumulative survival rate was 97.3% (4 implants had failed). Analysis of carefully standardized sequential radiographs indicated no significant changes in mean crestal bone levels between baseline and any of the examination times (after 6 months, 1 year, and 2 years in function). There were no detectable correlations between crestal bone loss and the factors implant length (7, 9, or 12 mm); implant diameter (3.5, 4.1, or 5.0 mm); implant position anteriorly or posteriorly in the maxilla; or whether or not the implant-supported crowns were splinted.

Adult↗
PubMed2001

[Development of the maxilla in patients with complete unilateral cleft palate surgically treated by a periosteal transplantation technic. A retrospective study of 15 surgical cases with an 18 year follow-up].

PURPOSE: The aim of this study was to assess retrospectively the long-term growth of the maxilla in subjects with unilateral total cleft treated initially with the tibial periosteal graft technique. PATIENTS AND METHODS: The study group included 15 patients with a mean 18 years follow-up (range 15-20 years). All patients had been operated on by the same surgeon. Only patients in stage DP3, one to two years after peak growth were retained for review. Delaire's architectural analysis was used to study anteroposterior and vertical growth of the maxilla. Transverse growth was studied with the Mars occlusal score. Bone generation induced by the periosteum was studied using the Björk Holmgren analysis. The quality of the palatine and nasal repair was studied using Pruzansky's criteria. RESULTS: Anteroposterior and vertical growth led to a normal maxilla in 53.3% of the cases and a moderate to severe retromaxilla (> 5 mm) in 46.7%. Complete symmetry was achieved for the nasal fossae in 20% of the cases and marked asymmetry was noted in 26%. The height of the nasal fossae was symmetrical in 60% of the cases with marked asymmetry in 26%. Mean production of alveolar bone reached 58% of the height of the alveolar bone filling. It was good in 46.6% of the cases, fair in 26.7% and weak in 26.7%. The occlusal score evidenced crossed occlusion in 33.3% of the cases for a hemisection and in 46.7% of the cases for an anterior section. Normal occlusion was achieved in 20%. The quality of palatine repair was found to be good with a normal mucosa in 86.7% of the cases. A fistula was present in 13.3%. CONCLUSION: The preoperative objectives of periosteal graft repair of unilateral complete clefts were achieved. This technique provides a closed scar-free palate. Nasal repair favored the development of an ample and functional airway. The periosteal graft produced bone in the anterior portion allowing a harmonious premaxillary region and stable nose support.

Adolescent↗
PubMed1997

[Splitting and widening of a narrow jaw ridge in the edentulous maxilla].

One of the most frequently occurring problems in oral implantology, especially in the maxilla, is the reduction of the alveolar ridge, caused by bone resorption in the edentulous and partly edentulous maxilla. A usually successful but clinically sometimes complicated way of solving this problem is the augmentation of the resorbed parts of residual ridges, particularly when autologous bone is being used. Implant placement usually follows in a later stage. The bone-splitting and bone-widening technique, on the other hand, is a more obvious method for the immediate placement of implants in those cases where the dimensions of the residual ridge are reduced by only some degree. When the resorption of the residual ridge is extreme, this method can eventually be combined with guided tissue regeneration. Crestosplit instruments are specially developed osteotomes for cleaving and widening the crest of the residual ridge, whilst, at the same time, compressing the cancellous bone. In applying this procedure, a bone preparation can be made with dimensions very close to the diameter of the implant to be placed, and without losing important bone-parts as in the case of drilling. Upon the completion of this procedure, only the last drill with the dimensions of the implant has to be used and the implant can thus be placed in the same session. In edentulous cases where the resorption is almost nil, bone preparation with the aid of this method is also to be preferred as the compression of the corticocancellous bone will considerably increase the bone contact with the implant surface. Especially in the maxilla this will lead to a better prognosis of the survival rate of the implant and to better esthetic results of the final prosthetic restoration.

Alveolar Bone Loss↗
PubMedDate not supplied

Assessment of accuracy of navigated implant placement in the maxilla.

PURPOSE: The use of computed tomography (CT) based intraoperative navigation has greatly improved surgery in many specialties. In this study, the precision of the SMN system (Zeiss, Oberkochen, Germany) for navigated drilling and following implant placement in the maxilla was evaluated. This study should demonstrate the suitability of navigation systems for computer-assisted implantation in the maxilla to avoid perforation of the maxillary sinus. MATERIALS AND METHODS: Sixty target drillings were carried out on 10 standardized polyurethane milling models after CT scanning. The models were produced with cranial open maxillary sinuses. The CT scans were performed with a slice distance of 1 mm. Then the CT data were transferred to the workstation of the SMN system and registration of the reference markers (fiducials) for superposition of the native and CT model was done. Referencing of the model was performed with the aid of a drilling tool. This drilling tool was used for later navigation-assisted drilling into the maxilla. The target of drilling was the maxillary sinus floor. The aim was to come as near as possible without perforation. The distance from the bottom of the drilling holes to the maxillary sinus floor was measured after sectioning of the model. In another 10 models, implants were placed after performing 60 navigated drilling holes. RESULTS: In the first part of the study, an average drilling depth of 6.97 mm and a mean distance to the sinus floor of 0.11 mm (standard deviation = 0.2) was found. In 13 specimens, the inferior border of the sinus was perforated. In the second part of the study, a perforation of the sinus floor by the implants was seen in 47 cases. The mean distance to the maxillary sinus was 0.25 mm (standard deviation = 0.2). DISCUSSION AND CONCLUSIONS: High precision of CT-based navigation for controlled preimplant drilling was seen, but a high incidence of penetrations into the maxillary sinus was caused by the subsequent implant placement.

Alveolar Bone Loss↗
PubMed1992

Prosthesis design for osseointegrated implants in the edentulous maxilla.

The position of osseointegrated implants in the edentulous maxilla is dictated by available bone and can vary widely among patients. Anatomy limits the amount of bone available for placement of osseointegrated implants. With increasing resorption, the number, length, and position of implants are further compromised. Bone grafts are frequently needed to place implants of adequate length. The variability of implant placement indicates the need for multiple prosthesis designs in the maxilla. Prosthesis design considerations are suggested for patients with minimal, moderate, and severe resorption of the edentulous maxilla.

Alveolar Bone Loss↗