Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Part I. Evaluation of anorganic bovine-derived bone matrix

The aim of this study was to evaluate clinically, histologically and histometrically the use of anorganic bovine bone matrix (i.e. Bio-oss) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Macaca mulatta) the 1st, 2nd and 3rd maxillary molars on one side of the jaws were extracted. The remaining bone between the alveolar crest and the bottom of the sinus was then reduced to 3-4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey and the sinuses were grafted with the bovine bone matrix. At that time, 2 IMZ pure titanium plasma coated implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into these previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants-unloaded group and delayed implants-unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited significant bone formation with integration of the bovine bone matrix particles to the new bone. Direct mineralized bone-to-implant contact was greater for the delayed implant placement groups than for the implants installed simultaneously with the sinus augmentation. Furthermore, the percentage of direct mineralized bone-to-implant contact was greater in the residual bone than in the augmented area. It was concluded that the anorganic bovine bone matrix facilitated bone formation and implant osseointegration in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure seemed to be preferable.     

Histologic analysis of clinically retrieved titanium microimplants placed in conjunction with maxillary sinus floor augmentation

In this study, a new approach involving placement and subsequent retrieval of titanium microimplants was employed for the histologic investigation of the implant-tissue interface in conjunction with maxillary sinus floor augmentation. Nine patients scheduled for sinus floor augmentation and simultaneous placement of Br?nemark implants were included in the study. After a sinus graft procedure and placement of implants, an additional microimplant was placed into the graft through the lateral wall of the sinus. At abutment connection, the microimplants were retrieved using a 3- or 5-mm-wide trephine drill. Six specimens were retrieved after 6 to 14 months from sites augmented with particulate radiated mineralized cancellous allograft. Another six implants were retrieved after 6 to 12 months from maxillary sinuses augmented with particulate autogenous bone grafts. The histologic analysis showed distinct differences between the two types of grafts. The sites with autogenous bones grafts displayed a normal morphology of bone and bone marrow, including formation of bone on the surfaces of the grafted particles and remodeling of newly formed as well as grafted bone. The bone was more mature after 11 to 14 months than at 6 months. The allografted sites had a mixed morphologic appearance of newly formed bone and nonviable allograft particles (about 75% of the total bone area) in loose connective tissue. Significantly more bone was found at the autografted than at the allografted implants. The use of autogenous bone for augmentation of the maxillary sinus floor resulted in a greater amount of viable bone surrounding the implant; however, simultaneous placement of implants apparently resulted in a low proportion of bone-implant contact after 6 to 14 months irrespective of graft type.     

Effects of functional endoscopic sinus surgery on maxillary sinus mucosa

OBJECTIVE: To compare the preoperative and postoperative changes on ciliary surface of maxillary sinus mucosa in patients treated with functional endoscopic sinus surgery. DESIGN: The maxillary mucosa of both the superolateral wall and the ostium were sampled during the operation and 6 to 12 months (mean duration, 7.6 months) after the operation. Ciliary surface was determined using scanning electron microscopy in combination with an image analyzer and was expressed in terms of ciliary area, which is the percentage of mucosal surface occupied by cilia. SETTING: The samples were taken at a hospital-based clinic. An electron microscopic study was performed at Mie University School of Medicine, Mie, Japan. PATIENTS: Sixteen patients (20 maxillary sinuses) undergoing functional endoscopic sinus surgery for treatment of chronic sinusitis. RESULTS: The mean (+/-SD) ciliary area before the surgery was 60.7%+/-28.8% and 39.9%+/-21.5% in the superolateral wall of the maxillary sinus and the ostium of the maxillary sinus, respectively. The ciliary area of the superolateral wall was significantly higher than that of the ostium (P<.001). The mean (+/-SD) postoperative ciliary area value was 74.3%+/-22.6% in the superolateral wall and 51.3%+/-16.1% in the ostium. These postoperative values were significantly higher than the preoperative values (P<.001). CONCLUSIONS: This study showed that the maxillary sinus mucosa in chronic sinusitis is capable of regeneration, and the damaged ciliated epithelium could return toward normal with the improvement of ventilation and drainage of the maxillary sinus following functional endoscopic sinus surgery.     

Maxillary sinus augmentation in the non-human primate: a comparative radiographic and histologic study between recombinant human osteogenic protein-1 and natural bone mineral

The posterior maxilla has traditionally been one of the most difficult areas to successfully place dental implants due to poor bone quality and close approximation to the maxillary sinus. Sinus augmentation procedures have become a viable means of assuring adequate bone for the placement of dental implants in this area. However, with the techniques currently employed, a considerable variation in the quality of bone attained with the sinus augmentation procedure exists. The purpose of this in vivo study was to evaluate the healing response and bone formation stimulated by 3 doses of recombinant human osteogenic protein-1 (rhOP-1), 0.25, 0.6, and 2.5 mg OP-1 per gram of collagen matrix; natural bone mineral; or collagen matrix alone (control) placed in the maxillary sinus of adult chimpanzees. Results were assessed using clinical, histologic, and radiographic techniques. Radiographic analysis of the computed tomography scans taken at 1 week, and 2.5, 4.5, and 6.5 months revealed a more rapid mineralization with the 2.5 mg OP-1/g collagen matrix and natural bone mineral treatment groups. The incremental bone mineral density (BMD) increase for these 2 treatments from 1 week to 2.5 months was over 2.5 times the increase found with the collagen matrix alone; these 2 treatments also had a higher BMD at the most superior slices evaluated when compared to the other 3 groups. Biopsy specimens were taken at 3.5, 5.5, and 7.5 months and for all 5 treatment groups bone formation was observed at all time points in the majority of the specimens. At 7.5 months the 2.5 and 0.6 mg OP-1/g collagen matrix treatment groups had an increase in the percent bone area when compared to the matrix alone control. In conclusion, these results demonstrate that sinus augmentation with natural bone mineral or 2.5 mg OP-1/g collagen matrix induce comparable radiographic and histologic evidence of bone formation and that both of these treatments performed superior to the control group of collagen matrix alone based upon all methods of evaluation.     

The use of osteotomes for sinus augmentation at the time of implant placement

The placement of endosseous dental implants is often hampered by the loss of alveolar bone. In the posterior maxilla, the presence of the maxillary sinus and less-dense bone present additional obstacles to successful implant placement. Existing methods of subantral augmentation require extensive surgical manipulation, often including a second surgical site for harvesting autogenous bone. The development of surgical osteotomes has facilitated the placement of implants in areas of minimal alveolar bone height in the posterior maxilla. This article describes the osteotome technique for sinus augmentation at the time of implant placement and presents a short-term evaluation of 34 implants placed in 18 patients.     

Long-term evaluation of the use of coralline hydroxyapatite in orthognathic surgery

PURPOSE: This prospective study was designed to evaluate the long-term clinical and radiographic results of porous block hydroxyapatite (PBHA) used as a synthetic bone graft in orthognathic surgery and craniofacial augmentation. PATIENTS AND MATERIALS: A total of 245 consecutive patients were treated initially. Inclusion criteria for this study included a minimum clinical and radiographic follow-up of 5 years. In addition, all patients with known implant failures were included regardless of whether they met the study criteria. There were 111 patients that met the criteria for inclusion in this study. All patients had undergone orthognathic surgery with rigid fixation and had had inlay or onlay PBHA implants placed. Ninety-six percent of the implants were placed through an intraoral approach. Long-term postoperative radiographs were visually compared with immediate postoperative radiographs for implant position, stability, resorption, and other significant radiographic changes. The clinical examination evaluated for signs and symptoms of infection, wound dehiscence, implant exposure, implant displacement, changes in the overlying mucosa, and development of oronasal or oroantral fistulae. RESULTS: Four hundred seventy-one implants were placed: 403 in the maxilla, 44 in the mandible, and 24 in the periorbital region. There were 289 implants placed in direct communication with the maxillary sinus. The average follow-up time was 7.2 years (range, 5.0 to 10.3 years). Twenty-three implants (4.9%) were removed during the evaluation period. Lateral maxillary wall grafting had 95.7% success, with nine implants being lost in three patients. One chin implant was removed because of dissatisfaction with the aesthetics. Seven (14%) midpalatal implants used for maxillary expansion were lost, primarily because of exposure of the implant to the oral or nasal cavity at the time of surgery. When PBHA was used for alveolar cleft grafting, there was a 100% failure rate. CONCLUSION: The use of PBHA as a bone graft substitute in orthognathic surgery and for facial augmentation showed a high percentage of success and efficacy. However, adequate soft tissue coverage in the nasal floor and on the palate are paramount for success of midpalatal implants. PBHA should not be used for alveolar cleft grafting. Rigid fixation for inlay implants in the maxilla is important to provide stress shielding of the material and minimize micromovement during the initial healing phase.     

Bicyclic derivatives of hexahydroaporphine: novel agents that lower intraocular pressure

The aim of this study was to evaluate clinically, histologically and histometrically the use of hydroxyapatite-coated dental implants in conjunction with maxillary sinus augmentation procedures. In 4 adult male Rhesus monkeys (Macaca mulatta) the 3 maxillary molars on 1 side of the jaws were extracted and the remaining bone between the alveolar crest and the floor of the sinus was reduced to 3-4 mm. After 3 months, maxillary sinus augmentation procedures were performed in each monkey and the sinuses were grafted with a porous hydroxyapatite bone graft (Interpore-200). At the same time, 2 hydroxyapatite-coated cylinder implants (IMZ) were immediately placed into the augmented sinuses (i.e. simultaneous-implants-loaded group). Four months later, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed-implants-loaded group). After 4 months, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that removal of the maxillary molars was performed 7 months after those in the opposite side, and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous-implants-unloaded group and delayed-implants-unloaded group) were obtained. Clinically, all loaded and unloaded implants were stable the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation with integration of the porous hydroxyapatite graft particles and hydroxyapatite-coat of the dental implants to the new bone. Histometric analysis indicated that on the loaded side the implants placed simultaneously with the sinus lift procedure exhibited greater direct mineralized bone-to-implant contact than the delayed placed implants. In addition, the percentage of direct mineralized bone-to-implant contact was significantly greater in the residual bone in comparison to the augmented area in all groups. Loading of the implants exhibited a positive effect on the percentage of direct mineralized bone-to-implant contact in the augmented area. It could be concluded that hydroxyapatite-coated implants may be of benefit when used in conjunction with sinus augmentation procedures.     

Endoscopically controlled sinus floor augmentation. A preliminary report

Sinus augmentation has been advocated to be a surgical technique with predictable results in peri-implant surgery. Endoscopic surgery of the maxillary sinus so far has been used as diagnostic procedure. In this paper, the use of endoscopy is described as a low invasive adjunctive technique in sinus floor augmentation. After preparation of the mucoperiosteum, bone grafts can be placed under endoscopic control between sinus floor and mucoperiosteum. A laterobasal approach via a small osteotomy and a transalveolar approach are possible for mucosal elevation and graft placement. First clinical results are reported. Endoscopic sinus lift may contribute to a reduction of perioperative morbidity, reduction of oroantral fistulae and control of graft position. The less invasive technique may allow to extend the indication for sinus augmentation.     

Short-term healing following the use of calcium sulfate as a grafting material for sinus augmentation: a clinical report

Because of the frequent lack of bone in the posterior maxilla, sinus augmentation has become a commonly practiced treatment modality. Many different materials have been used for augmenting the sinus, and the ideal graft is yet to be found. The present article reports the results of sinuses grafted with calcium sulfate in 2 patients. Bone biopsies were harvested 9 months after the augmentation procedure. In the first patient, 3 titanium threaded-cylinder implants were placed in the grafted area after 9 months, while in the second, 1 acid-etched, screw-shaped titanium implant was placed simultaneously with the graft. Light microscopic evaluation revealed new bone formation with ongoing remodeling and progressive lamellar maturation in the specimens. No remnants of the alloplastic material were detectable in any section, either within the bone or in the medullary tissue. When reevaluated at the uncovering procedure, the implants were radiographically and clinically judged to be osseointegrated. These observations suggest that, when used in the appropriate form and with the proper technique, calcium sulfate is a promising graft material for sinus augmentation, producing adequate quantity and quality of new bone for implant placement.     

How to prevent the various neuralgic complaints after operation of maxillary sinus? (author's transl)

In order to avoid multiple neuralgic complaints after operations of maxillary sinus the following advice for cautions operative procedures is as follows: 1. A vertical incision in the mucosa of the fossa canine behind the eye-tooth instead of the usual horizontal section. 2. A small dorsolateral fenestration in a part of less nervous ramification in the facial bone layer of the antrum of High-more. 3. The limitation of resection of the mucous membrane in pathological areas of the sinus. 450 operations of the maxillary sinus were done in this way, which resulted in a lower rate of postoperative neuralgic complaints. Another advantage was the minimized intraoperative bleeding and the absence of postoperative swelling and haematoma formation of the cheek.     

1H and 15N resonance assignment of neural cell adhesion molecule module-2

This article presents a simple, inexpensive method for precisely locating the floor of the maxillary sinus, as well as the presence of any septa, at the time of sinus augmentation surgery. Using an anesthesia light wand placed transnasally to illuminate the sinus, the surgeon can reliably elevate the lateral maxillary wall overlying the sinus with relative ease without fear of placing the osteotomy cuts too far from the sinus floor. The same procedure can be used postoperatively to evaluate the density of the bone graft placed into the sinus prior to closure.     

An evaluation of measures of synonymous codon usage bias

OBJECTIVE: The aim of this study was to determine whether bone quality, as assessed by osteometry and histologic parameters, can be used to predict implant integration in conjunction with maxillary sinus reconstruction. STUDY DESIGN: Twelve patients with severely atrophied maxillary alveolar processes were treated through use of a two-stage surgical reconstructive strategy with implant placement 4 months after bone grafting. Bone biopsy specimens taken from the iliac crest peroperatively and from the sinus inlay sites 1, 2, 4, 6, or 12 months postoperatively were analyzed by light microscopy and osteomorphometry. Bone mineral content was measured by osteometry. RESULTS: Osteometric and osteomorphometric data (trabecular bone volume [%], assessment of chromatin staining, and an osteocyte index) registered for the biopsy specimens were not statistically correlated with implant failure. CONCLUSIONS: Prognostic evaluation of implant survival is difficult. The tested methods did not contribute to the improvement of guidelines for the clinical handling of these patients.     

Survival of cylindrical implants in composite grafted maxillary sinuses

PURPOSE: This retrospective study investigated the survival of dental implants placed in the maxilla after composite grafting of the sinus and an average of 55 months of loading. PATIENTS AND METHODS: Maxillary sinuses of 88 patients were grafted with autogenous cancellous bone combined with dense hydroxyapatite particles. After an average healing period of 3.4 months, hydroxyapatite-coated titanium endosseous implants were placed. A total of 388 implants were placed in grafted sinus floors, and 82 were placed in onlay grafted nonsinus position in the canine region. The implants were loaded with overdentures and fixed bridges 4 months (mean) after implantation, with a follow-up for a mean of 55 months. RESULTS: The cumulative implant survival was calculated according to the Kaplan-Meier method. Implant survival from the time of loading was 89% in full reconstructed cases and 90% in partially edentulous cases. The overall cumulative implant survival rate, including the loss in the surgical stage, was 82%. CONCLUSION: Implant loss in composite grafted maxillae after 70 months of follow-up was similar to loss in nongrafted maxillae.     

Long-term outcome after frontal sinus obliteration with an ionomer bone substitute in the cat. I: Histological results

BACKGROUND: Osteoplastic frontal sinus surgery in combination with sinus obliteration may occasionally be performed for indications such as severe sinus inflammations, extensive wall fractures involving the nasofrontal duct, or osteomas. The material most frequently used for this obliteration is autogenous adipose tissue. Autografts such as muscle, cartilage, and bone chips have been also recommended for this purpose. In order to avoid the surgical procedure required for harvesting an autograft from other body sites, alloplastic materials have been suggested for frontal sinus obliteration. METHODS: In an animal study using cats, the mucous lining of the frontal sinus was removed, the nasofrontal duct sealed with semifluid ionomer cement, and the cavity filled up with a solid and porous ionomer-based microimplant. RESULTS: Histological investigations were performed up to two years after surgery. Increasing obliteration of the sinus cavity by bone regeneration, starting from the sinus wall, as well as formation of connective tissue between the cement grains was detected as early as one month after implantation. Osteoblasts lining the osteoid layer were considered to be an indication of active bone regeneration. Osteogenesis inside the sinus cavity continuously progressed during the following months. Two years after implantation, osteoid and newly mineralized bone encircled the microimplants leading to an almost complete obliteration. There was no evidence for mucosal regeneration or foreign body reaction. CONCLUSIONS: Because of its osteoconductive effect, biocompatibility, and biostability the ionomer-based microimplant is a suitable alloplastic material for frontal sinus obliteration.     

Mean fetal growth curve adjustment]

OBJECTIVE: Three-dimensional models created by milling machines and stereolithography on the basis of 3-dimensional computed tomography scans have become essential in the diagnosis and therapy planning of oral and maxillofacial disorders. The purpose of this study, based on 3 clinical cases, was to examine the advantages of using 3-dimensional computed tomography scans and 3-dimensional milling models of the maxillary sinus before operative sinus elevation and of developing an operative layout with the aid of 3-dimensional models. REPORT DESIGN: Three patients with atrophy of the maxillary alveolar ridge received computed tomography scans before operative sinus elevation with iliac bone transplants and simultaneous dental implantation. These computed tomography data were used to create 3-dimensional graphic and plastic reconstructions of the maxillary sinuses. RESULTS: The 3-dimensional milling models enabled the development of an exact preoperative layout that took into consideration the exact shape of the iliac bone and the selection of dental screw implants. Furthermore, the models offered the possibility of producing an acrylic device for precise implant insertion. Precise planning resulted in good success with implantation 2 years after surgery. CONCLUSION: Three-dimensional diagnosis and treatment layout have become an acknowledge method of operative maxillary sinus floor augmentation combined with simultaneous dental implantation in the upper jaw in difficult cases of sinus lift operations. As far as transplant shape and sinus anatomy are concerned, this has resulted in greater intraoperative precision. A 1-step procedure can thus be performed for augmentation and implantation through use of a well-adapted block transplant and dental screw implants in patients with extensive alveolar ridge atrophy.     

Indirect sinus augmentation procedures using one-stage anatomically shaped root-form implants

Sinus augmentation procedures are a standard part of implant dentistry. Indirect sinus augmentation procedures reduce the magnitude of the surgery when sinus lift procedures are necessary. This article describes a variation of the indirect augmentation of maxillary sinuses. The surgery is performed through small diameter surgical access openings. This modified indirect sinus augmentation procedure is combined with the immediate placement of one-stage dental implants that effectively seal the surgical access openings and have an anatomical exit profile for easier restoration.     

Clinical assessment of olfactory dysfunction in Parkinson''s disease

The possibility of placing endosseous implants in the edentulous maxilla is frequently reduced by inadequate bone volume of the residual ridge. In totally edentulous maxillae with knife-edge conformation, insufficient thickness is frequently associated with insufficient height of the residual ridge in the posterior maxilla because of pneumatization of the maxillary sinuses. This surgical method combines grafting of the maxillary sinuses, onlay grafts on the buccal side of maxillary posterior segments, and sagittal osteotomy of the anterior maxilla with interpositional bone grafts. Five to six months after maxillary reconstruction, Br?nemark implants were placed and, after osseointegration occurred, implant-supported dental prostheses were fabricated. Three patients have been treated with this method and 22 implants have been placed. The mean follow-up after final prosthetic rehabilitation has been 16 months; survival rate has been 100%. Despite the small number of patients and the short follow-up, preliminary results have shown very promising results.     

Sinus inlay bone augmentation: comparison of implant positioning after one- or two-staged procedures

PURPOSE: This study was undertaken to compare implant angulation and position after one- or two-stage sinus inlay bone augmentation. PATIENTS AND METHODS: Twenty patients were retrospectively selected; group 1 (n = 10) was operated on with a one-stage procedure, and group 2 (n = 10) with a two-stage operation. Casts processed for the final permanent or temporary bridgework were collected and photographed from an oblique anterior view paralleling the alveolar crest on the right and left sides, as well as from an occlusal view. The angle between impression pins inserted in the abutments relative to the true vertical was recorded. In the occlusal view, the midpoints of the abutments were related to an individual computerized superimposed parabola. RESULTS: The implants inserted during the one-stage procedure were generally placed more palatally (Wilcoxon rank sum test, P = .0101) and angled more palatally (P = .0009) compared with those placed with the two-stage operation. CONCLUSION: This study showed that the two methods of treating patients by sinus inlay bone augmentation differed significantly with regard to placement and angulation of the implants. A two-stage procedure seems to offer the surgeon more optimal conditions for positioning the implants.     

Nucleolar organizer regions in human maxillary sinus squamous cell carcinoma

A silver colloid technique for nucleolar organizer regions (AgNOR) was applied to paraffin sections of maxillary sinus squamous cell carcinomas (MSSCC) of 25 patients. The patients were divided into two groups, one with MSSCC recurring in the primary lesion after treatment with radiotherapy, chemotherapy and/or surgery and one without recurrence. Notable differences between the numbers of NOR in neoplastic epithelia and the normal mucosa were observed (P = 0.0001), but there were no differences between the numbers of NOR in the recurrent and non-recurrent carcinomas. This investigation found no prognostic importance in the number of AgNOR in MSSCC.     

Coralline hydroxyapatite: a bone graft alternative in foot and ankle surgery

The use of coralline hydroxyapatite has become a viable bone grafting alternative. Its efficacy has been well established through multiple human and animal studies. Coralline hydroxyapatite enhances osteogenesis by providing a biocompatible lattice for the passage and assembly of vascular, fibroblastic, and osteoblastic tissues. It also provides support for surrounding osseous structures. The uses of this material are expanding into the realm of foot and ankle surgery. Its consideration as an appropriate bone graft substitute as well as multiple case studies demonstrating its surgical applicability are discussed. The implants utilized at Thorek Hospital and Medical Center over the past eight years, with an average follow-up of three and one-half years, have proven to be a valuable resource for augmentation where an osseous defect has occurred.