Volumetry of simulated bone grafts in the edentulous maxilla by computed tomography: an experimental study.

OBJECTIVE: To determine the precision of CT for calculating the volume of bone grafts to the maxilla. METHODS: Plaster of Paris was used to simulate bone as onlay and inlay grafts to the maxillary alveolus and sinus in a dry skull. Two mm thick axial CT scans were obtained. The area of the graft on each slice was measured and volumes calculated according to the formula V(graft)=Sigma of areas x the thickness of each section. Scans were repeated with the skull at approximately +5 degrees and -5 degrees to the horizontal plane and the calculations repeated. The real volume was calculated by the displaced water technique. Precision was estimated as reliability coefficient. RESULTS: The reliability coefficients for the right and left inlay and the onlay grafts were 0.97, 0.6 and 0.96 respectively. CONCLUSION: Calculations of the volume of both inlay and onlay grafts to the maxilla from axial CT is precise.

A clinical study of changes in the volume of bone grafts in the atrophic maxilla.

OBJECTIVES: To evaluate the volumetric changes in bone grafts to the severely atrophic edentulous maxilla over 6 months. METHODS: Ten edentulous patients received autogenous bone as buccal onlay grafts to the maxilla and bilaterally particulate bone grafts to the maxillary sinus. Two mm contiguous axial CT scans were obtained 1 to 2 weeks and 6 to 7 months postoperatively. The area of each graft was measured and the volume calculated according to the formula V(graft)=Sigma of areas x the thickness of each section. RESULTS: The volume of the inlay and onlay grafts was reduced by an average of 49.5 and 47% respectively of the initial volume. The coefficient of variation was greater in the onlay group (0.79) compared with the inlay group (0.38). CONCLUSIONS: The volumetric changes in buccal onlay and sinus inlay grafts after 6 months of healing seem similar although there was a wide range in both groups.

A prospective randomized study of 1- and 2-stage sinus inlay bone grafts: 1-year follow-up.

The purpose of the present study was to compare the success of and surgical differences between 1- and 2-stage sinus inlay bone grafts and implants after 1 year in function. The individual risk for implant failure in grafted areas among 1-stage patients was about twice the risk in 2-stage patients (odds ratio 2.3, CI 0.6; 8.5). The risk for implant failure in non-grafted areas was significantly lower (P < .05) than in grafted areas, regardless of the technique used. Forty edentulous patients, selected according to strict inclusion criteria from consecutive referrals, were allocated to one or other of the 2 sinus-inlay procedures. Twenty patients received bone blocks fixed by implants to the residual alveolar crest in a 1-stage procedure (group 1). In another 20 patients, particulated bone was condensed against the antral floor and left to heal for 6 months before implants were placed (group 2). An almost equal number of implants was placed in the patients of each group, 76 in the 1-stage procedure and 74 in the 2-stage procedure. Additionally, 72 and 66 implants were placed in the anterior non-grafted regions of group 1 and group 2 patients, respectively. After 1 year in function, a total of 20 implants failed in 1-stage patients, versus 11 in 2-stage patients. Sixteen and 8 implants, respectively, of these were placed in grafted bone. All but one 1-stage patient received the planned fixed prosthetic restorations, but 1 restoration was redesigned after the first year in function because of a functionally unacceptable prosthetic design. At the 1-year follow-up, one 2-stage patient lost her prosthesis as the result of multiple implant failures. Bruxism and postoperative infections were the only parameters that could be related to implant failure, however, depending on the statistical method used.

Implants and sinus-inlay bone grafts in a 1-stage procedure on severely atrophied maxillae: surgical aspects of a 3-year follow-up study.

This 3-year follow-up study compares implant treatment in 39 1-stage sinus-inlay block-grafted patients (study group) with 37 patients treated without bone grafting (reference group), all of whom were edentulous in the maxilla and were treated over the same time period. The cumulative success rate (CSR) of implant stability after 3 years in the study group was 75.3% in grafted areas and 82.2% in non-grafted areas. The CSR after 3 years in the reference group was 93.1%. The mean marginal bone resorption after 3 years of loading was 1.4 mm in grafted areas and 1.6 mm in non-grafted areas in the study group and 1.1 mm in the reference group. Complications noted during the postoperative healing periods correlated significantly with implant failures later on (P < .05). Since prosthesis stability (CSR) after 3 years was 94.9% in the study group and 97.3% in the reference group, it can be concluded that 1-stage sinus-inlay block grafts can be regarded as a safe method with a predictable outcome for use on patients with severely atrophied edentulous maxillae, although increased failure rates are to be expected for implants placed in bone-grafted regions.

Oral implants in combination with bone grafts. A 3-year retrospective multicenter study using the Brånemark implant system.

A retrospective, multicenter, Scandinavian study of bone grafting of alveolar processes of severely atrophic jaws in combination with implant insertion was conducted with 150 patients. Five different grafting techniques were assessed: local or full onlay; inlay; combination of onlay/inlay grafts; and LeFort I osteotomies. The majority of the patients were treated using a one-stage approach (n = 125) and all had autogenous bone grafts. A total of 781 Brånemark implants were inserted, of which 624 were placed in bone grafts and alveolar bone. Twenty-five patients (17%) dropped out during the follow-up period of three years. Within the remaining patients, 77% of the inserted implants (n = 516) were still in function at the end of the follow-up period. A further ten implants were kept mucosa-covered, resulting in an overall implant survival rate of around 80%. Onlays, inlays and LeFort I osteotomies showed almost the same success rates (76-84%), whereas the onlay/inlay technique gave rise to less favourable results (60%). Most of the observed losses (n = 131) took place during healing and the first year of loading. More implants were lost when they were inserted simultaneously with the grafting (23%) than when they were placed in a second stage (10%). The latter technique was used mainly in combination with local onlay grafting (16/25). The failure percentage for implants inserted in non-grafted bone (11%) was lower than for those inserted in bone grafts and alveolar bone (25%). The surviving implants of treated and followed patients served, in 88% of the cases (n = 110), to support fixed bridges or overdentures, albeit, in some instances (n = 23), after additional implant placement. In only 15 patients was it necessary to fall back on conventional removable prostheses or fixed partial bridges.

A prospective clinical evaluation of different single-tooth restoration designs on osseointegrated implants. A 3-year follow-up of Brånemark implants.

Since single-tooth implant restorations were introduced 12 years ago (Jemt 1986), there has been continuous development both in the technical design and the aesthetic outcome of the treatment. In order to ensure high quality in single-tooth implant treatments a clinical follow-up study was carried out on patients treated with modifications to the original regimen. In this study 69 consecutive patients were provided with 80 single-tooth implant restorations. The patients were followed for 3 years. There was continuous development of the prosthetic design during the time of the study, allowing us to analyse possible prognostic differences for the different prosthetic treatments. This study confirms earlier reports which describe the single-tooth implant treatment as a safe method with few surgical complications and minimal marginal bone loss. Only 1 implant was lost during the follow-up period and the average marginal bone loss was 0.48 mm over the 3-year follow-up period. Crowns veneered with acrylic and with gold casted directly to the abutments, screwed onto the implants, led to recurring prosthetic complications and gave an appearance of rapid ageing. The first generation of crowns made following the Cera-One design, sometimes produced a gap between the crown and the abutment associated with significant marginal bone loss during the first year. Few surgical or prosthetic complications were noted with cemented all-ceramic constructions, although the number of these crowns in this study was limited.

Antibody response in patients with osteomyelitis of the mandible.

Patients with mandibular osteomyelitis had quantification of 10 antibodies against certain bacterial proteins and polysaccharides. Sera from 31 patients with acute or chronic osteomyelitis of the mandible and from 17 healthy controls were analyzed. Some patients showed low levels of investigated antibodies in general and a lack of specific antiteichoic acid antibodies, as well as of different antipneumococcal antibodies particularly. Two patients with therapy-resistant osteomyelitis showed IgG2 and IgG3 subclass deficiency. They had replacement therapy with intravenous 10 or 15 gm immunoglobulin every 3 weeks for 6 months. Both patients showed considerable improvement in their clinical symptoms after treatment with immunoglobulin. This study indicates that impaired humoral immune response may be of importance in subgroups of patients with osteomyelitis of the mandible.

Blood flow in jaw bones affected by chronic osteomyelitis.

In order to study circulatory changes throughout the course of chronic osteomyelitis of the jaws, blood flow in bone affected by osteomyelitis was assessed in 14 patients, by means of laser Doppler flowmetry (LDF). The difference in perfusion between the osteomyelitic bone and corresponding sites on the opposite healthy jaw was evaluated. The patients were classified into two groups according to the clinical activity of their disease. A significantly reduced bone blood flow was recorded in the jaw during non-active stages, while an increased flow was associated with the initial stage of disease and the inflammatory exacerbations. No pre-existing vascular disorders were discovered prior to the development of this disease. However, a long standing local inflammation of the jaw bone was associated with a persistent reduction in blood flow. In 12 healthy subjects, blood flow in the left jaw was found not to be statistically different to that in the right jaw.

Plasma protein changes in chronic osteomyelitis of the jaws.

In the present study, quantification of different serum proteins known as inflammatory reactans was performed during different stages of chronic osteomyelitis of the jaws, to find a suitable tool for evaluation of treatment. In all 46 sera from 17 osteomyelitis patients and 6 healthy subjects were analyzed. Repeated measurements of alfa-1-antitrypsin, orosomucoid and haptoglobin could be recommended for following-up the effect of treatment, although too extensive conclusions should not be drawn from single measurements. The serum levels of these proteins seemed to co-vary with the clinical activity of the disease. Since the synthesis of the immunoglobulins only indirectly reflects the inflammatory activity, they are not considered to be suitable markers of inflammation, although their concentration in serum varied with the clinical activity. A certain "mass of inflammation" seemed to be necessary before raised values of C-reactive protein were detected. No information was gained from albumin concentration.

Periapical lesions of mandibular bone: difficulties in early diagnostics.

It is often difficult to establish a correct diagnosis on the basis of initial clinical and roentgenologic symptoms in mandibular bone disease. In this paper these problems are discussed, and some suggestions are made to overcome them. The discussion is based on cases of osteogenic sarcoma, histiocytic lymphoma, and chronic osteomyelitis. The patients were a boy and two middle-aged women, all of them with primary clinical symptoms of pain and swelling, diffuse roentgenologic changes in mandibular bone, uncertain response to treatment, and an unusual progress of the disease.

A proliferative inflammation in the mandible caused by implantation of an infected dental root. A possible experimental model for chronic osteomyelitis.

In order to provide a better understanding of the reactions of bone affected by an infectious stimulus, infected dental roots were implanted into the mandibular bone of 5 monkeys (Macaca fascicularis). The roots were infected by micro-organisms belonging to the monkeys' oral plaque flora. Following an observation period of 6 months, the monkeys were sacrificed. The mandibles were dissected. Radiographs were taken and then the mandibles were prepared for histology. In the mandibles where the infected roots had been implanted, advanced inflammatory changes were seen. Bacteria, however, were only found within the implanted roots, not in the surrounding tissue in spite of a heavy inflammatory reaction. The interaction between infection and inflammation is discussed on the basis of these observations. The role of possible neural transmittor substances in the pathogenesis of the inflammatory disease is also discussed. The signs and symptoms of the proliferative inflammatory changes provoked in this experiment are compared to those of chronic osteomyelitis.

Vascular changes after experimentally-induced inflammation in the mandible.

In this study, the vascular supply of an experimentally-induced inflammatory reaction in 5 monkey mandibles is examined. A barium sulfate injection method, combined with contact microradiography was used. In all monkeys, marked vascular changes were seen within the areas of inflammation. Vertical nutrient branches were interrupted shortly after leaving the inferior alveolar artery, and a conglomerate of thin irregular vessels were seen interspersed through newly formed bone trabeculae. The vascular supply to the neighbouring teeth seemed to be unaltered; neither was there any evidence of vascular thrombosis or vasculitis.

Infectious foci in chronic osteomyelitis of the jaws.

Chronic osteomyelitis of the jaws has a varied clinical appearance and an unclear etiology. In a retrospective study based on case histories and histological material from 24 patients with chronic osteomyelitis, no specific correlation could be found between clinical symptoms and morphological changes in bone. In 10 patients, bacteria were found in certain foci such as osteocytic lacunae of necrotic bone and dentinal tubules of embedded tooth fragments. In these foci, the bacteria probably escaped the immunological response as well as the antibiotic treatment. From these foci, the bacteria might maintain an inflammatory reaction in the surrounding bone. In some patients, the mandibular canal seemed to be a pathway for the spreading of the inflammatory process.

Fibrous dysplasia of bone and concomitant dysplastic changes in the dentin.

Fibrous dysplasia of bone and dentinal dysplasia have not been classified as related conditions. However, the present report describes a patient with both polyostotic fibrous dysplasia and dysplastic changes in the dentin. One bone lesion was first discovered on the right side of the mandible on a routine roentgenogram. There was an atypical radiolucency apical to a short-rooted molar with an obliterated pulp. Additional lesions were found on the left side of the mandible in the maxilla, in the frontal and occipital bones, in the ilium, in the proximal ulnae, and in the ribs. All lesions demonstrated an increased uptake of Tc99. A biopsy specimen of bone from the right side of the mandible showed small calcified islands in a cell-rich connective tissue. Microscopic analysis of the right first molar showed irregularly shaped dentin with the dentinal tubules arranged in a whorl-like fashion surrounding an almost completely obliterated pulp chamber and canal. Healing after tooth extraction and after the bone biopsy was unremarkable. After 6 months the alveolus was reorganized and the bone patterns appeared normal, although the radiolucent areas inferior to the teeth remained unchanged. The concomitant occurrence of dysplastic changes in bone and teeth may be a sign of a generalized defect in the mesenchymal hard-tissue-forming cells.