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Background: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ).

Methods: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty-two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a one-stage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded.

Results: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 ISQ) for all implants. The increase was marginally significant (generalized estimating equation z-statistic = 1.79; P value = 0.07).

Conclusions: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%.

BACKGROUND: Rehabilitation with implant-supported bridges in patients with insufficient bone volumes may require bone reconstructive procedures in conjunction with or prior to implant placement. Clinical follow-up studies using turned titanium and bone grafts have demonstrated higher failure rates than when used in nongrafted patients. Improved bone integration has been demonstrated for oxidized titanium implants; however, their clinical performance in bone reconstruction situations is not known. PURPOSE: This study was performed to analyze the survival and stability of oxidized titanium implants placed in patients subjected to reconstructive jaw surgery at one clinic. MATERIALS AND METHODS: Two hundred oxidized titanium implants (Mk III, TiUnite, Nobel Biocare AB, Göteborg, Sweden) were placed in 47 patients in conjunction with or secondary to six different reconstructive procedures owing to insufficient bone volume. In all six groups, implant stability was assessed by resonance frequency analysis and manually checked for rotation stability at implant insertion, at the time of abutment connection, and after a minimum of 12 months of loading of the prosthetic construction. Periapical radiographs were taken after a minimum of 12 months of loading (mean 21 months) for evaluation of the marginal bone levels. The mean clinical follow-up period was 30 months. RESULTS: Of the 200 implants, 199 were considered osseointegrated at the time of abutment surgery. At the 12-month postloading follow-up, another two implants were considered not stable. Three implants (1.5%) were ranked as unsuccessful. CONCLUSION: Clinical experience with 200 consecutive oxidized implants in various reconstruction situations shows a successful outcome, with only three failures (1.5%) during a mean follow-up period of 30 months.

BACKGROUND: The placement of endosseous implants in edentulous areas is frequently limited by inadequate bone volume of the residual ridge. Local bone grafts from the mandible are a convenient source of autogenous bone for alveolar reconstruction prior to implant placement. PURPOSE: The aim of the present study was to document and compare the morbidity and the frequency of complications occurring at two intraoral donor sites: the mandibular symphysis and the mandibular ramus. MATERIAL AND METHODS: This study reviewed 53 consecutively treated patients: 29 with autogenous bone grafts from the mandibular symphysis and 24 with mandibular ramus bone grafts. Each patient received a questionnaire 18 months after surgery regarding problems that may have occurred during the postoperative period. RESULTS: In the patients in whom bone was harvested from the mandibular ramus, there were fewer postoperative symptoms immediately after the operation than with mandibular symphysis harvesting. Twenty-two of the 29 patients with symphysis grafts experienced decreased sensitivity in the skin innervated by the mental nerve 1 month after the operation. Five of the 24 patients with ramus grafts experienced decreased sensitivity in the vestibular mucosa corresponding to the innervation of the buccal nerve. Eighteen months after the surgery, 15 of the 29 patients in the symphysis group still had some decreased sensitivity and presented with permanent altered sensation. Only one of the patients grafted from the mandibular ramus presented with permanent altered sensation in the posterior vestibular area. No major complication occurred in the donor sites in any of the 53 patients. CONCLUSION: The results of this study favored the use of the ascending mandibular ramus as an intraoral donor site for bone grafting.

Dental caries and periodontal disease are the major causes for tooth loss. While dental caries commonly involve the posterior teeth in both jaws, the teeth most commonly lost due to periodontal problems are the first and second molars in the maxilla. As a consequence, the upper posterior jaw is frequently edentulous. Implant therapy today is a predictable treatment modality for prosthetic reconstruction of edentulous patient. Insufficient amounts of bone, due to atrophy following loss of teeth or due to the presence of the maxillary sinus, can make it impossible to insert implants in the posterior maxilla. During the 1970s and 1980s, Tatum, Boyne and James and Wood and Moore first described maxillary sinus floor augmentation whereby, after the creation of a lateral access point, autologous bone grafts are inserted to increase crestal bone height and to create the necessary conditions for the insertion of implants. This surgical procedure requires a two-stage approach and a double surgical site: first, bone is harvested from a donor site and transplanted to the recipient site; then, after a proper healing period of between 4 to 6 months, the implants are inserted. This kind of bone reconstruction, even if well documented, has its limitations, not least in the creation of two different surgical sites and the consequent increased risk of morbidity. In 2004, Lundgren et al. described a new, simplified technique for the elevation of the sinus floor. The authors showed that by lifting the sinus membrane an empty space was created in which blood clot formations resulted in the establishment of new bone. The implants were placed simultaneously to function as “tent poles”, thus maintaining the sinus membrane in a raised position during the subsequent healing period. An essential prerequisite of this technique is to obtain optimal primary implant stability from the residual bone in the sinus floor. An extremely resorbed maxillary sinus floor, with, for example, less than 2-3 mm of poor quality residual bone, could impair implant insertion.

The aims of the present research project were (i) to evaluate the donor site morbidity and the acceptance level of patients when a bone graft is harvested from the anterior iliac crest, (ii) to evaluate implant stability, new bone formation inside the maxillary sinus and marginal bone resorption around the implants in long term follow up when maxillary sinus floor augmentation is performed through sinus membrane elevation and without the addition of any grafting material, (iii) to investigate new bone formation inside the maxillary sinus, in experimental design, using a resorbable space-maker device in order to maintain elevation of the sinus membrane where there is too little bone to insert implants with good primary stability.

In Paper I, 70 consecutively treated patients were retrospectively evaluated in terms of postoperative donor site morbidity and donor site complications. With regard to donor site morbidity, 74% of patients were free of pain within 3 weeks, whereas 26% had a prolonged period of pain lasting from a few weeks to several months. For 11% of patients there was still some pain or discomfort 2 years after the grafting surgery. Nevertheless, patients acceptance was high and treatment significantly improved oral function, facial appearance, and recreation/social activities and resulted in an overall improvement in the quality of life of formerly edentulous patients.

In Paper I and III, some differently shaped space-making devices were tested on primates (tufted capuchin - Cebus apella) in two experimental models aimed at evaluating whether a two-stage procedure for sinus floor augmentation could benefit from the use of a space-making device to increase the bone volume and enable later implant installation with good primary stability, without the use of any grafting material. An histological examination of the specimens showed that it is possible to obtain bone formation in contact with both the Schneiderian membrane and the device. In most cases the device was displaced. The process of bone formation indicated that this technique is potentially useful for two-stage sinus floor augmentation. The lack of device stability within the sinus requires further improvement in space-makers if predictable bone augmentation is to be achieved.

In Paper IV, a total of 84 patients were subjected to 96 membrane elevation procedures and the simultaneous placement of 239 implants. Changes of intra-sinus and marginal bone height in relation to the implants were measured in intraoral radiographs carried out during insertion after 6 months of healing, after 6 months of loading and then annually. Computerised tomography was performed pre-surgically and 6 months post-surgically. Resonance frequency analysis measurements were performed at the time of implant placement, at abutment connection and after 6 months of loading. The implant follow-up period ranged from a minimum of one to a maximum of 6 years after implant loading. All implants were stable after 6 months of healing. A total of three implants were lost during the follow-up period giving a survival rate of 98.7%. Radiography demonstrated an average of 5.3 ± 2.1 mm of intra-sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4 ± 6.1) and small changes over time.

In conclusion, harvesting bone from the iliac crest could result in temporary donor site morbidity, but in 11% of patients pain or discomfort was still present up to 2 years after surgery. However, patient satisfaction was good despite this slow or incomplete recovery, as showed by the quality of life questionnaire. Maxillary sinus membrane elevation without the use of bone grafts or bone substitutes results in predictable bone formation both in animal design, where the sinus membrane is supported by a resorbable device, and in clinical conditions, where the membrane is kept in the upper position by dental implants. This new bone formation is accompanied by a high implant survival rate of 98.7% over a follow-up period of up to 6 years. Intra-sinus bone formation remained stable in the long-term follow-up. It is suggested that the secluded compartment allowed bone formation in accordance with the principle of guided tissue regeneration. This technique reduces the risks of morbidity related to bone graft harvesting and eliminates the costs of grafting materials.

BACKGROUND: Bone grafting is a surgical technique for the reconstruction of the atrophic edentulous maxilla prior to treatment with endosseous implants. The anterior iliac crest is a commonly used donor site.

PURPOSE: The aim of this study was to evaluate the donor site morbidity and complications when harvesting corticocancellous bone from the medial table of the anterior iliac crest and compare this with results when bone was harvested from the lateral and superior table of the anterior iliac crest. In addition, the outcome of the oral rehabilitation was evaluated by means of a quality-of-life questionnaire.

MATERIAL AND METHODS: The study was composed of 70 consecutively treated patients with a mean age of 56 years. The patients were retrospectively evaluated with regard to postoperative donor site morbidity and complications at the donor site.

RESULTS: For the donor site morbidity, 74% of the patients were free of pain within 3 weeks, whereas 26% of the patients had a prolonged period of pain lasting from a few weeks to several months. For 11% of the patients, there was still some pain or discomfort 2 years after the grafting surgery. For gait disturbance the figures were similar: 79% had no problems after 3 weeks. For the eight patients who still had some pain after 2 years, which was considered permanent, three also had gait disturbance. There was a total of three major complications (4%), one iliac wing fracture and two neurologic injuries.

CONCLUSION: When harvesting a large amount of unicortical corticocancellous bone blocks from the the superolateral site of the iliac crest with a "peel off" technique, morbidity and complication rates do not differ significantly compared with those of the traditional anterior medial approach. Oral rehabilitation with maxillary reconstruction with bone grafts from the iliac crest and endosseous implants significantly improved oral function, facial appearance, and recreation/social activities and resulted in an overall improvement in quality of life in formerly edentulous patients.

Background: Previous studies have pointed out that the mere elevation of the maxillary sinus membrane promotes bone formation without the use of augmentation materials.

Purpose: This experimental study aimed at evaluating if the two-stage procedure for sinus floor augmentation could benefit from the use of a space-making device in order to increase the bone volume to enable later implant installation with good primary stability.

Materials and Methods: Six male tufted capuchin primates (Cebus apella) were subjected to extraction of the three premolars and the first molar on both sides of the maxilla to create an edentulous area. The sinuses were opened using the lateral bone-wall window technique, and the membrane was elevated. One resorbable space-making device was inserted in each maxillary sinus, and the bone window was returned in place. The animals were euthanatized after 6 months, and biopsy blocks containing the whole maxillary sinus and surrounding soft tissues were prepared for ground sections.

Results: The histological examination of the specimens showed bone formation in contact with both the schneiderian membrane and the device in most cases even when the device was displaced. The process of bone formation indicates that this technique is potentially useful for two-stage sinus floor augmentation. The lack of stabilization of the device within the sinus demands further improvement of space-makers for predictable bone augmentation.

Conclusions: It is concluded that (1) the device used in this study did not trigger any important inflammatory reaction; (2) when the sinus membrane was elevated, bone formation was a constant finding; and (3) an ideal space-making device should be stable and elevate the membrane to ensure a maintained connection between the membrane and the secluded space.

BACKGROUND: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants.

PURPOSE: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants.

MATERIALS AND METHODS: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections.

RESULTS: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity.

CONCLUSIONS: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results.

Objectives: To investigate the long-term clinical and radiographic results of the maxillary sinus membrane elevation technique where implants were inserted in a void space created by the elevation of the sinus membrane without adding any graft material.

Materials and methods: A total of 84 patients were subjected to 96 membrane elevation procedures and simultaneous placement of 239 implants. Changes of intra-sinus and marginal bone height in relation to the implants were measured in intraoral radiographs taken at insertion, after 6 months of healing, after 6 months of loading and then annually. Computerized tomography was performed pre-surgically and 6 months post-surgically. Resonance Frequency Analyses measurements were performed at the time of implants placement, at abutment connection and after 6 months of loading. The implant follow-up period ranged from a minimum of one to a maximum of 6 years after implants loading.

Results: All implants were stable after 6 months of healing. A total of three implants were lost during the follow-up period giving a survival rate of 98.7%. Radiography demonstrated on average 5.3±2.1 mm of intra-sinus new bone formation after 6 months of healing. RFA measurements showed adequate primary stability (implant stability quotient 67.4±6.1) and small changes over time.

Conclusion: Maxillary sinus membrane elevation and simultaneous placement of implants without the use of bone grafts or bone substitutes result in predictable bone formation with a high implant survival rate of 98.7% during a follow-up period of up to 6 years. The intra-sinus bone formation remained stable in the long-term follow-up. It is suggested that the secluded compartment allowed for bone formation according to the principle of guided tissue regeneration. The high implant survival rate of 98.7% indicated that the implants sufficiently supported the fixed bridges throughout the study period. This technique reduces the risks for morbidity related to harvesting of bone grafts and eliminates the costs of grafting materials.

Background: The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation.

Purpose: The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption.

Materials and Methods: Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein.

Results: The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group.

Conclusion: The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.

Thirty patients with severely resorbed maxillae were treated in a one-stage procedure using bone graft and implant placement. A horseshoe-shaped bone graft was taken from the iliac wing and fixed to the residual maxillary ridge using titanium implants, which supported the prostheses placed after a 6-month healing period. The material constituted two groups: a development group, the first 10 patients; and a routine group, the following 20 patients. At the 3-year follow-up, the implant survival was 87.5% and the prosthesis stability was 100% in the routine group. The probing depth did not change during the follow-up period, while the grafted region decreased in volume during the first postoperative year. The patients reported improved chewing ability and improved life quality. Very few technical and prosthodontic complications occurred.

A double-blind, randomized cross-over trial was carried out in 50 patients undergoing surgical removal of bilaterally impacted lower wisdom teeth. Surgery in each patient was performed twice and paracetamol 1000 mg was administered once preoperatively and once postoperatively. The time interval to additional analgesic intake and the pain intensity up to and at that time were assessed. There was no difference between the 2 treatments. It was concluded that preoperative paracetamol does not offer any clinical advantage in patients who undergo surgical removal of impacted lower wisdom teeth.

BACKGROUND: Bovine hydroxyapatite (Bio-Oss, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long-term histologic fate of this material is not well understood. PURPOSE: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure. MATERIALS AND METHOD: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis. RESULTS: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 +/- 12.6% nonmineralized tissue, followed by 21.2 +/- 24.5% lamellar bone, 14.5 +/- 10.3% BH particles, and 10.2 +/- 13.4% woven bone. The nonmineralized tissue seen in bone-forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 +/- 19.0% (p < .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 +/- 22.8% (p < .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 +/- 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle-bone contact had increased from 28.8% +/- 19.9% after 6 months to 54.5 +/- 28.8% after 3 years (p < .05). CONCLUSION: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3-year specimens. Moreover, bone-integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available.

The purpose of this prospective clinical study was to evaluate the 3-year outcome of 30 maxillary sinus floor augmentations with an autogenous bone-deproteinized bovine bone mixture (20:80). A total of 108 dental implants were placed after 6 months of graft healing. After another 6 months, the occlusion was restored with fixed prostheses and followed for 3 years of functional loading. Clinical and radiographic examinations of the sinuses and implants, including computerized tomography (CT) were performed. The stability of the implants was evaluated by means of resonance frequency analyses (RFA). After 3 years of functional loading with fixed bridges, 15 of 108 implants were lost giving a cumulative survival rate (CSR) of 86%. All followed patients, except one, had fixed bridges in function after 3 years of loading. The mean marginal bone loss was 1.3+/-1.1 mm after 3 years. RFA showed a mean implant stability quotient (ISQ) value of 66+/-4.1 after 3 years with no significant difference between implants in grafted and residual bone. Examination with CT showed that 67% of the maxillary sinuses were healthy prior to treatment and 71% after 3 years of loading. It was concluded that grafting of the maxillary sinus with a mixture of autogenous bone and deproteinized bovine bone is a reliable procedure.

Biopsies were taken from 16 out of 20 consecutive referral patients 6 to 8 months after maxillary sinus floor augmentation with a mixture of bovine hydroxyapatite (BH), autogenous bone particles and fibrin glue. Four days prior to biopsy retrieval the patients were given a single dose of tetracycline to label bone forming sites. Fluorescence microscopy of 100 microm thick sections revealed active bone formation in conjunction with the BH particles in 14 of 15 specimens analysed. Light microscopy and morphometry of ground sections from 16 patients showed various amounts of mineralised bone tissue in all except one specimen. In the latter case, the BH particles were encapsulated by a dense fibrous connective tissue. Sections from the augmented areas were occupied by non-mineralized tissue (54.1+12.6%), lamellar bone (21.2+24.5%), BH particles (14.5+10.3%) and woven bone (10.2+13.4%). The non-mineralized tissue seen in bone forming areas consisted of a loose connective tissue, rich of vessels and cells, and in the periphery of a more dense fibrous connective tissue. Woven bone with large and scattered osteocyte lacunae was bridging between the BH particles and the lamellar trabecular bone. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. It is concluded that the tested implant material has bone conducting properties. The bone associated with the BH particles after 6 to 8 months of healing was mainly woven.

PURPOSE: The purposes of this study were 1) to evaluate the survival rate of implants placed in maxillary sinuses augmented with bovine hydroxyapatite and autogenous bone 6 months before implant surgery and 2) to estimate dimensional changes of the bone graft with time using a new radiographic method. PATIENTS AND METHODS: Thirty maxillary sinuses in 20 consecutive patients with severe resorption (mean, 3.8 mm of remaining alveolar bone) were augmented with a mixture of 80% bovine hydroxyapatite and 20% autogenous bone mixed with fibrin glue to enable the placement of screw-shaped dental implants. After 6 months of primary healing, 108 implants were placed and followed with clinical and radiographic examinations during the first year of loading. Measurements of changes in height, width, and length of the grafted material were made on tomographic Scanora (Soredex Orion Corporation Ltd, Helsinki, Finland) and panoramic radiographs taken 3 and 12 months after grafting and after 1 year of bridge loading. RESULTS: Ten implants in 6 patients were lost during the study (9 before loading and 1 after 1 year of functional loading), for a survival rate of 90.7%. All patients received fixed restorations, and the bridge survival rate was 100% after 1 year of loading. Small (<10%) but statistically significant dimensional changes in the grafted material were seen during the study period. CONCLUSIONS: Acceptable short-term results can be obtained with implants placed after the use of bovine hydroxyapatite and autogenous bone for maxillary sinus floor augmentation. These grafts show good resistance to resorption.

Dento-alveolar trauma often leads to a need for reconstruction of the alveolar crest before an implant can be placed. Although autogenous bone grafts is considered the 'gold standard', this may be associated with patient morbidity and graft resorption. Consequently, the use of bone substitutes has increased. Today, a substantial number of biomaterials are available on the market, but only a few are well documented. The user should be aware that these biomaterials have different properties: resorbable or non-resorbable, time of resorption and resorption mechanism. The purpose of this review is to describe the function of various bone substitutes and indications for their use in reconstructive implant surgery and to give an overview of the current situation.

PURPOSE: This study was designed to clinically and histologically evaluate the integration of titanium implants in different grafting materials used for maxillary sinus augmentation procedures. MATERIALS AND METHODS: A total of 21 patients and 36 maxillary sinuses were augmented with (1) autogenous particulated bone from the mandibular ramus, (2) bovine hydroxyapatite (BH) with membrane coverage, or (3) an 80/20 mixture of BH and autogenous bone. The grafts were allowed to heal for 6 to 9 months prior to placement of microimplants for histology and standard implants for prosthetic rehabilitation. After another 6 months of healing, when abutments were connected, the microimplants were retrieved for histologic and morphometric analyses. The outcome of the standard implants was clinically evaluated after 1 year of loading. RESULTS: The mean bone-implant contact was 34.6 +/- 9.5%, 54.3 +/- 33.1%, and 31.6 +/- 19.1% for autogenous bone, mixture of 20% autogenous bone/80% BH, and 100% BH, respectively. The corresponding values for the bone area parameter were 37.7 +/- 31.3%, 39.9 +/- 8%, and 41.7 +/- 26.6%. The BH area was found to be 12.3 +/- 8.5% and 11.8 +/- 3.6% for 20% autogenous bone/80% BH and 100% BH, respectively. There were no statistically significant differences for any parameter between any of the groups. After 1 year of loading, 6 of the 33 implants placed in autogenous bone grafts, 2 of the 35 implants placed in the BH/autogenous bone mixture, and 2 of 43 implants placed in BH were lost. There were no statistically significant differences between any of the groups. DISCUSSION: The histomorphometric analysis showed no differences between the 3 groups, indicating that autogenous bone graft can be substituted with bovine hydroxyapatite to 80% or 100% when used for maxillary sinus floor augmentation. The effect of adding autogenous bone remains unclear but may allow for a reduction of the healing time. CONCLUSION: The results from this clinical and histologic study indicate that similar short-term results can be expected when using autogenous bone, BH, or a mixture of them for maxillary sinus floor augmentation and delayed placement of dental implants.

BACKGROUND: Dental implants need appropriate bone volume for adequate stability in the rehabilitation after tooth loss. In the severely atrophic posterior maxilla, the clinical success of implant treatment sometimes requires a vertical ridge augmentation in the maxillary sinus floor. PURPOSE: The purpose of this investigation was to evaluate a maxillary sinus floor augmentation technique using a replaceable bone window, elevation of the membrane, placement of implants, and injection of the patient's own venous blood to fill the voids. MATERIALS AND METHODS: Six patients with need of maxillary sinus floor augmentation participated in the study. After preparation of a replaceable bone window in the lateral aspect of the sinus and careful elevation of the Schneiderian membrane, a total of 14 Brånemark implants (TiUnite, MK III, Nobel Biocare AB, Göteborg, Sweden) were installed in the residual bone penetrating into the sinus cavity. The sinus cavity was then filled with peripheral venous blood and the bone window replaced and stabilized with a medical tissue glue (Aron Alpha A, Sankyo, Inc., Tokyo, Japan) to prevent blood leakage from the created compartment in the maxillary sinus. RESULTS: After a healing period of a minimum of 6 months, new bone was successfully generated in all 14 implant sites as judged from radiographs. One of the 14 implants failed, corresponding to a survival rate of 92.9% after a follow-up period ranging 12 to 34 months. CONCLUSIONS: The present case series demonstrate that the creation of a secluded space in the maxillary sinus and filling with venous blood results in bone formation at simultaneously installed dental implants over a 6-month period.

Background: In cases when the alveolar crest is too narrow to host an implant, lateral augmentation is required. The use of autogenous bone blocks harvested from the iliac crest is often demanded. One disadvantage is the associated patient morbidity.

Purpose: The purpose of this study was to clinically and histologically evaluate the use of morselized impacted bone allograft, a novel technique for reconstruction of the narrow alveolar crest.

Materials and methods: Two patients with completely edentulous maxillae and one partially edentulous, with a mean age of 77 years (range 76-79 years) were included in the study. The alveolar crest width was < 3 mm without possibility to place any implant. Bone grafts were taken from a bone bank in Gavle Hospital. Bone from the neck of femur heads was milled to produce bone chips. The milled bone was partially defatted by rinsing in 37 degrees C saline solution. After compression of the graft pieces with a size of 15 mm (height), 30 mm (length), and 6 mm (width), they were then fit to adapt to the buccal surface of the atrophied alveolar crest. One piece was placed to the right and one to the left side of the midline. On both sides fibrin glue was used (Tisseel (R), Baxter AG, Vienna, Austria) to stabilize the graft. After 6 months of graft healing, dental implants were placed, simultaneously biopsies were harvested and in one patient two oxidized microimplants were placed. At the time of abutment connection, microimplants were retrieved with surrounding bone for histology. Fixed screw-retained bridges were fabricated in mean of 7 months after implant surgery. Radiographs were taken before and after implant surgery and after 1 year of loading.

Results: Sixteen implants with an oxidized surface were placed (TiUnite (R), Nobel Biocare AB, Goteborg, Sweden). After 1 year of functional loading, all implants were clinically stable. The marginal bone loss was 1.4 mm (SD 0.3) after 1 year of loading. The histological examination showed resorption and subsequent bone formation on the allograft particles. There were no signs of inflammatory cell infiltration in conjunction with the allograft. The two microimplants showed bone formation directly on the implant surface.

Conclusions: This study shows that morselized impacted bone allograft can be used to increase the width of the atrophied narrow alveolar crest as a good alternative to autogenous bone grafts in elderly patients. The histological examination of biopsies revealed a normal incorporation process and no signs of an immunological reaction. Further studies with larger samples are of important to be able to conclude if equal results can be obtained using morselized impacted bone allograft as for autogenous bone graft.

BACKGROUND: Mechanoreceptors situated in the periodontal ligament provide detailed information about intensive and spatial aspects of tooth loads, which support the neural control of masticatory forces. We asked whether a reduced periodontal ligament due to periodontitis, and, thus, an altered mechanoreceptive innervation of the teeth, would affect masticatory behavior when subjects used incisors to hold and split food. METHODS: We tested 11 subjects with reduced periodontal tissue support that rendered 30% to 70% alveolar bone loss for at least one pair of opposing anterior incisors. Forces were recorded when subjects used their affected incisors to hold half of a peanut for approximately 4 seconds and then split it. Age- and gender-matched healthy subjects served as the control group. None of the participants showed acute oral symptoms or massive periodontal inflammation. RESULTS: The test group used greater force when holding food between the teeth (1.1+/-0.4 N [ mean+/-1 SD]) compared to the control group (0.4+/-0.2 N). Hold forces used by subjects in the test group were also more variable, both within and between trials. The increase in bite force applied to split the peanut was slower and more hesitant for subjects in the test group compared to the control group. CONCLUSIONS: Reduced periodontal tissue support accompanies impaired regulation of masticatory forces. Faulty mechanoreceptive innervation of the periodontal ligament explains the elevated hold force, whereas a change in biting strategy due to the weakened support of the teeth may account for the more defensive food-splitting behavior.

Purpose: To compare long-term survival and clinical outcomes of endosseous implants with different surface characteristics in patients with sinus elevation procedures, autologous bone grafting, and delayed implant placement. Materials and Methods: Implant survival, peri-implant soft tissue conditions, marginal bone level, intrasinus apical bone level, and sinus health were studied in patients subjected to autologous bone graft and delayed placement of implants with turned or oxidized surfaces. After a minimum of 5 years of functional loading, all patients were clinically examined regarding gingival pocket depth (PD) and bleeding on probing (BoP). The marginal bone level (MBL) was measured in intraoral radiographs. Cone beam computed tomography was used to evaluate the apical bone level (ABL) of the implants and intrasinus conditions. Results: Twenty-eight patients received sinus elevation and a total of 92 dental implants. Thirteen patients received 47 implants with a turned surface, and 15 patients received 45 implants with an oxidized surface. Mean follow-up was 10 years (range, 5 to 19 years). No significant difference was found between the two implant surfaces in terms of PD, BoP, MBL, or ABL. Four patients (14%) exhibited radiographic signs of sinus pathology, with opacification, polyplike structures, and thickening of the sinus membrane. Radiographic signs of sinus pathology were not correlated to implant survival or to the investigated parameters. Conclusion: Grafting of the maxillary sinus floor with intraorally harvested bone and delayed placement of either turned or oxidized implants results in equally high long-term survival rates, stable marginal and apical bone levels, and good peri-implant soft tissue health.

OBJECTIVES: The purpose of this study was to compare two implant types of similar shape but with different surfaces with respect to implant failure. MATERIAL AND METHODS: A total of 136 patients were treated with Nobel Biocare Implants between January 2001 and December 2002. Totally 394 implants were placed, of which 199 were oxidized titanium implants (Nobel Biocare TiUnite and 195 with turned titanium surface (Nobel Biocare Mark III. Sixty-three patients underwent a one-stage surgical protocol, of which 24 were objected to early functional loading. The remaining 73 patients were treated with a traditional two-stage surgical protocol. All patients were followed for a minimum of 5 months after loading of the implants. Implants were classified as survivals when clinically stable and fulfilling purported function without any discomfort to the patient, with no signs of infection or ongoing pathologic process. RESULTS: Seven implants were lost in five patients (two males and three females), six in the maxilla and one in the mandible. All failed implants were Mark III implants, inserted following the traditional two-stage protocol. The implant success rate was 98.2% for the whole-patient group, divided as a 100% success rate following the implants with oxidized surface (Nobel Biocare TiUnite compared with a success rate of 96.4% with implants with turned surface (Nobel Biocare Mark III).

Bone grafts from the hip in combination with Brånemark self-tapping fixtures have been used to rehabilitate patients with extremely resorbed maxillae. Experiences and results from the first ten consecutive cases have been analyzed to form the basis for further use of the method. Eight of 57 fixtures placed have been lost to date. Surgical complications, including exposure of the bone transplant, have occurred in three patients. The method should be used with caution, and cases should be meticulously chosen to exclude those who do not have proper motivation to endure the long-lasting and demanding surgical and prosthetic procedures required. The combined use of implants and transplants should not be used routinely until a long-term evaluation of the method and results has been made.

The effect of synovial membrane products and mechanical pressure upon the metabolism of articular cartilage proteoglycans has been studied in vitro. The degradation of cartilage proteoglycans was studied in an organ culture system and measured as the release of [³⁵S ] sulphate from prelabelled cartilage. The effect of synovial membrane products upon the synthesis of proteoglycans was studied in a chondrocyte monolayer system and the effect of mechanical pressure upon the synthesis of proteoglycans in an organ culture system. In both types of experiments [³⁵S] sulphate was used as precursor.

The findings may be summarized as follows

1 Conditioned synovial medium (control-SM) enhanced the degradation and reduced the synthesis of cartilage proteoglycans. In addition the degradation was further enhanced when the synovial tissue had been cultured in the presence of dextran sulphate.

2 Conditioned medium from synovial tissue cultured in the presence of indo-methacin (indo-SM), significantly reduced the synthesis of cartilage proteoglycans in chondrocyte cultures and reduced, although non-significantly, the degradation of proteoglycans in whole cartilage cultures.

3 Addition o f the prostaglandins E₁ or E₂ (PGE₁ or PGE₂ ) together with indo-SM to the cartilage cultures greatly enhanced cartilage degradation whereas the addition of PGE₁ or PGE₂ together with control-SM had no effect compared with that of control-SM alone.

4 Conditioned medium from synovial tissue cultured in the presence of low doses of glucocorticoids reduced cartilage degradation compared with control-SM. However, addition of control-SM together w ith low concentrations of glucocorticoids to the cartilage cultures significantly enhanced cartilage degradation.

5 Conditioned medium from synovial tissue cultured with actinomycin D or cycloheximide did not enhance cartilage degradation compared with cartilage cultured alone.

6 A continuous pressure of approximately 30 kgfcm^-2 on cultures of cartilage reduced both the synthesis and the degradation o f cartilage proteoglycans.

Although it is difficult to extrapolate from the in vitro to the in vivo situation, it is proposed that some factor(s) from the synovial membrane have the capacity to enhance the degradation and reduce the synthesis o f articular cartilage proteoglycans. From these experiments it cannot be completely excluded that treatm ent of arthritic joints with non-steroidal or streroidal anti-inflammatory drugs may result under certain conditions in enhanced joint damage. It is also suggested that under certain conditions the metabolism o f cartilage proteoglycans could be directly affected by mechanical stress.

Oblique sliding osteotomy of the mandibular rami was performed on 41 patients by either an intra-oral (21 patients) or extra-oral (20 patients) approach. The temporomandibular joints were radiographed preoperatively and then immediately and 18 months postoperatively. Signs of structural changes were recorded so as to compare the two approaches to osteotomy. The most common findings following the operation were signs of sclerosis and bone remodelling in 85% and 73% respectively of the two groups but these differences were not statistically significant.

Objectives: To compare resorption of a synthetic biphasic calcium phosphate (BCP) bone–graft substitute with deproteinized bovine bone (DBB) used for human maxillary sinus augmentation.

Materials and methods: Eleven patients underwent bilateral maxillary sinus floor augmentation with DBB in one side and a BCP (40%β-tricalcium phosphate (β-TCP) and 60% hydroxyapatite) in the contralateral side. Simultaneously, with the augmentation on each side a microimplant was placed vertically from the top of the alveolar crest penetrating the residual bone and the grafting material. Eight months after initial surgery the microimplants were retrieved with a surrounding bone core. The composition of residual graft material and surrounding bone was analysed by scanning electron microscopy and energy dispersive X-ray spectroscopy.

Results: Residual graft material of both types was present as 10–500 μm particles in direct contact with, or completely surrounded by, newly formed bone; smaller particles were also present in non-mineralized tissue. In the case of BCP the bone–graft substitute interface showed evidence of superficial disintegration of particles into individual grains. Median Ca/P ratios (at.%), determined from >200 discreet sites within residual graft particles and adjacent bone, were: DBB: 1.61 (confidence interval [CI] 1.59–1.64); BCP: 1.5 (CI 1.45–1.52); DBB-augmented bone: 1.62 (CI 1.59–1.66); BCP-augmented bone: 1.52 (CI 1.47–1.55); P=0.028 for DBB vs. BCP and DBB- vs. BCP-augmented bone. The reduction in Ca/P ratio for BCP over the healing period is consistent with the dissolution of β-TCP and reprecipitation on the surface of calcium-deficient hydroxyapatite.

Conclusion: The β-TCP component of BCP may be gradually substituted by calcium-deficient hydroxyapatite over the healing period. This process and superficial degranulation of BCP particles may influence the progress of resorption and healing.

Purpose: The aims of the present study were to compare a novel biphasic calcium phosphate (BCP) with deproteinized bovine bone (DBB) for maxillary sinus floor augmentation in a split-mouth design and to perform a clinical follow-up of dental implants placed in the augmented sinuses. Materials and Methods: Partially or completely edentulous patients requiring bilateral sinus augmentation were included in the study. The patients were randomized for augmentation with BCP (test) and DBB (control) in the contralateral side. Eight months after grafting, dental implants were placed. After 3 years of graft healing, core biopsy specimens were obtained from the grafted areas for histologic and histomorphometric analyses. After 3 years of functional implant loading, implant survival/success rates and clinical indices were assessed and radiographic examination and resonance frequency analysis were performed. Results: Nine completely edentulous patients and two partially edentulous patients (mean age, 67 years) who required bilateral sinus augmentation were included in the study, and 62 implants were placed. The mean values for the area of newly formed bone in the retrieved specimens were 29% +/- 14.3% and 32% +/- 18.0% for BCP and DBB, respectively; the percentage of graft particles in contact with bone was 38% +/- 10.9% in the BCP group and 44% +/- 12.1% in the DBB group (no statistical significant differences between groups). The mean values for the area of BCP particles and DBB particles were 20% +/- 7.5% and 24% +/- 13.5%, respectively (difference not significant). One dental implant was lost from each group, resulting in an overall implant survival rate of 96.8% after 3 years of loading. Conclusion: After 3 years, a similar amount of newly formed bone was present regardless of the biomaterial used. The choice of biomaterial did not seem to influence implant survival rates. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:1151-1162

Purpose: This randomized, controlled study was designed to compare bone formation around microimplants with a sandblasted, acid-etched surface placed at the time of maxillary sinus floor augmentation with a synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB).

Materials and Methods: Nine completely edentulous patients and two partially edentulous patients (six women, five men) with a mean age of 67 years (range, 50 to 79 years) requiring bilateral sinus augmentation were included in the study. The patients were randomized for augmentation with BCP (test) in one side and DBB (control) in the contralateral side. At the time of augmentation, one microimplant on each side was placed vertically from the top of the alveolar crest, penetrating the residual bone and the grafting material. After 8 months of graft healing, at the time of ordinary implant placement, all 22 microimplants were retrieved with a surrounding bone core for histologic analyses.

Results: The bone-to-implant contact in the BCP group was 64.6% +/- 9.0%, versus 55.0% +/- 16.0% for the DBB group. The difference was not significant. The corresponding values for the area of newly formed bone in the biopsies were 41.1% +/- 9.8% and 41.6% +/- 14.0% for BCP and DBB, respectively. There were significantly more DBB particles in contact with newly formed bone than BCP particles (87.9 +/- 18.2% versus 53.9 +/- 26.1%; Wilcoxon rank sum test; P = .007).

Conclusion: In this randomized, controlled clinical trial, new bone formation and bone-to-implant contact around microimplants with a sandblasted, acid-etched surface was found to be equivalent between sinuses augmented with BCP or DBB. Significantly more DBB particles than BCP particles were in contact with newly formed bone, but the clinical relevance of this has yet to be established.

When implants are used for restoration of a jaw with a residual dentition, the possibility of combining implants with natural abutments may be considered. In a longitudinal comparative study, 26 patients (15 women & 11 men, age 49-84 years) with residual anterior dentitions were treated with two different designs of fixed partial dentures bilaterally in the posterior maxilla. On one side the reconstruction was supported by implants only, while on the contralateral side an implant and a tooth in combination were used. The patients were followed at intervals of 3, 6, 12 and 24 months after loading of the implants. 95 implants were placed, of which 11 non-loaded. A total of 10 implants failed, 7 prior to loading and three within the first three months of service (88.0+/-SE 6.7% cumulative survival for tested implants after two years' follow-up). There was no difference in failure rate for the implants in the two different prosthesis designs. The total mean loss of marginal bone height close to the implants was within acceptable standards, but was more pronounced at the implants not combined with teeth. The results indicate a correlation between the prosthesis design and the loss of marginal bone.

BACKGROUND: Various maxillary sinus floor augmentation techniques using bone grafts and bone substitutes are frequently used to enable placement of dental implants in the posterior maxilla. A previous case report demonstrated the possibility of promoting bone formation in the sinus by lifting the membrane without using a grafting material. However, the predictability of the technique is not known. PURPOSE: The aim of this study was to investigate whether sinus membrane elevation and the simultaneous insertion of titanium implants without additional grafting material constitute a valid technique for bone augmentation of the maxillary sinus floor. MATERIALS AND METHODS: The study group comprised 10 patients in whom a total of 12 maxillary sinus floor augmentations were performed. A replaceable bone window was prepared in the lateral sinus wall with a reciprocating saw. The sinus membrane was dissected, elevated superiorly, and sutured to the sinus wall to create and maintain a compartment for blood clot formation. One to three dental implants were inserted through the residual bone and protruded at least 5 mm into the maxillary sinus. The bone window was replaced and secured with the overlying mucosa. Bone height was measured directly at each implant site at the time of insertion. Resonance frequency analysis (RFA) was performed on each implant at the time of initial placement, at abutment surgery, and after 12 months of functional loading. Computed tomography (CT) was performed in the immediate postoperative period and 6 months later, prior to exposure of the implants. RESULTS: A total of 19 implants (Brånemark System, TiUnite, Nobel Biocare AB, Gothenburg, Sweden) in lengths of 10 to 15 mm were placed, with an average residual bone height of 7 mm (range, 4-10 mm). All implants remained clinically stable during the study period. Comparisons of pre- and postoperative CT radiography clearly demonstrated new bone formation within the compartment created by the sinus membrane elevation procedure. RFA measurements showed mean implant stability quotient values of 65, 66, and 64 at placement, at abutment connection, and after 12 months of loading, respectively. CONCLUSIONS: The study showed that there is great potential for healing and bone formation in the maxillary sinus without the use of additional bone grafts or bone substitutes. The secluded compartment created by the elevated sinus membrane, implants, and replaceable bone window allowed bone formation according to the principle of guided tissue regeneration. The precise mechanisms are not known, and further histologic studies are needed. Sinus membrane elevation without the use of additional graft material was found to be a predictable technique for bone augmentation of the maxillary sinus floor.

BACKGROUND: Maxillary sinus floor-augmentation techniques are frequently used to increase the bone volume in the posterior edentulous maxilla to enable placement and integration of titanium implants. PURPOSE: The purpose of this report is to document an unexpected healing pattern after maxillary sinus surgery and to discuss the implications for future bone-augmentation techniques. MATERIALS AND METHODS: In a patient referred for sinus augmentation, an intrasinus mucosal cyst was removed 3 months prior to the planned augmentation procedure. A replaceable bone window was prepared in the lateral aspect of the sinus wall. The cyst was removed, the ruptured mucosa was sutured, and the bone window was replaced, resulting in a secluded space in the sinus. RESULTS: After 3 months of healing, the space between the replaced bony window and the lifted sinus membrane was filled with newly formed bone. The surgical technique was repeated in a second patient and resulted in a similar bone reformation pattern. CONCLUSION: Surgical trauma and the creation of a secluded space between the bone surfaces and the sinus mucosa result in spontaneous bone formation in the maxillary sinus. The surgical approach described may be used to achieve bone reformation to enable placement of dental implants without the addition of any grafting material.

This study presents the results from 20 consecutive patients treated with an autogenous bone graft from the iliac crest. In ten patients the graft was placed in the maxillary sinuses and the floor of the nose (inlay group). Ten patients, in addition to the inlay graft, had a corticocancellous bone block secured with mini-screws to the anterior maxillary ridge (inlay/onlay group). Endosteal implants (Brånemark) were placed six months after surgery. A total of 136 implants were placed, of which eight failed to integrate during the six-month healing period. A further 15 implants were lost during the follow-up period. For the inlay group the average follow-up period was 22 months and for the inlay/onlay group 19 months. Donor site morbidity was significantly less when iliac bone was harvested with a trephine (inlay group) than in patients treated with our routine procedure for bone harvesting (inlay/onlay group). Surgical technique, donor site morbidity, implant survival and patient acceptance are presented.

The aim of the present study was to histologically analyse the bone graft-titanium implant interface after six and twelve months of healing for a simultaneous approach and after six months for a delayed approach. For this purpose, screw-shaped c.p. titanium microimplants, 2 mm in diameter and 5 mm long, were placed and retrieved at different time intervals in ten consecutive patients with severely resorbed maxillae and treated with iliac cortico-cancellous bone grafts and titanium implants in a two-stage procedure. The histomorphometrical analyses of ground sections of the specimens showed a higher degree of bone-implant contact and more bone filling the implant threads in the delayed approach microimplants. This was probably due to the partly revascularized grafted bone in the delayed approach being able to respond to the surgical trauma, resulting in interfacial bone formation. It is concluded that the results from the present study favour the use of a delayed approach when using free autogenous bone grafts and titanium implants for reconstruction of the severely atrophied maxilla.

The clinical results of oblique sliding (subcondylar) osteotomy of the mandibular rami performed by the extraoral or intraoral approach were compared. The patient material comprised 40 patients with mandibular prognathism. Twenty patients were operated upon using the extraoral approach and 20 patients were operated on using the intraoral approach. All patients had intermaxillary fixation for 7 weeks. The patients in both groups were followed up for 18 months. The experience of the operations was that the intraoral approach gave a shorter operation time than the extraoral approach. The extraoral approach, however, gave better visibility in the operation field and greater possibilities of manipulating the proximal fragment into an optimal position. In the follow-up evaluation, there were no significant differences between the two surgical techniques with regard to dental relapse, post-operative occlusion and mandibular function.

Thirty patients with extremely resorbed maxillae had reconstructive bone grafts from the ala iliaca and endosseous implants in a one-stage procedure. The first ten patients constituted a development group and the following 20 patients a routine group. The marginal bone level and implants success rate was evaluated in a prospective long-term follow-up for a minimum of 10 years (10-13 years). Clinical and radiographic examinations were performed at 6 months and then annually up to 5 years. The final examinations were performed at the 10-year follow-up. The bridges were removed at every clinical examination. Marginal bone loss was seen up to the 3-year examination, where it averaged 4.6 mm in the routine group. Between the 3- and 10-year follow-up no significant change was registered. The initial bone loss was probably due to the design of the 3.6 mm conical unthreaded marginal part of the implant. The implant success rate was 83.1% in the routine group. Failures mostly occurred during the first 2 years (14 out of 20). A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

Thirty patients with severely resorbed edentulous maxillae underwent combined treatment of iliac bone onlay graft and titanium implants. The patients were followed for 3 years. They were radiographically examined before surgery to evaluate the bone volume at the intended implant sites. Only 13/156 implant sites were suitable for implant insertion. The bone level at the implant surfaces was evaluated after 6 months and 1, 2, and 3 years, respectively. There was a continuing decrease of the bone level throughout the follow-up period with a mean loss of 4.9 mm after 3 years and with no difference between sexes. Twenty-six implants were radiographically examined before removal, and only three of these implant sites showed radiographic signs of failure. The soft-tissue profile was analyzed cephalometrically by the subtraction technique. The upper lip generally moved inward and the apex of the nose and the columella downward and inward. The anterior facial height increased in most of the patients, resulting in a downward and inward change of the lower lip, the mentolabial sulcus, the soft-tissue pogonion, and the soft-tissue gnathion.

A total of 30 patients, 10 in a developmental group and 20 in a routine group, with extremely resorbed maxillae were treated with bone grafting from the hip and implant placement in a one-stage procedure. All patients were followed for a minimum of 5 years and were examined regarding the long-term success rate of the implants and marginal bone level. The implant success rate was 74.6% for the whole patient group and 85.8% for the routine group, after 5 years. The marginal bone along the implant surface decreased continuously, up to 3 years and thereafter the bone level stabilized. In the routine group, changes in bone graft dimensions over time were also evaluated by computerized tomography. The mean height of the bone graft postoperatively at all implant sites was 8.3 mm. The total mean bone height, including bone graft and residual alveolar crest, was 12.4 mm. After 5 years the total bone height had decreased to a mean of 10 mm. The mean width of the bone graft was 12 mm postoperatively and 8.7 mm at the 5-year examination. A substantial amount of bone can be gained in patients with extremely resorbed maxillae, when treated with bone graft according to the procedure described in this study.

A double-blind, randomized analgesic trial was carried out in 150 patients undergoing surgical removal of their 2 impacted lower wisdom teeth. The analgesic efficacy of effervescent acetaminophen 500 or 1000 mg in a 2-dose regimen was compared with that of diflunisal 500 mg in a single dose. Each dose was taken when subjectively needed and the pain intensity was measured on a visual analog scale during the 10-hour period after first medication. The best pain reduction was achieved with diflunisal. The difference between diflunisal 500 mg and acetaminophen 1000 mg was significant, as was that between acetaminophen 1000 and 500 mg. The peak effect after the first dose occurred later but was greater with diflunisal than with acetaminophen. Patients needing analgesics at low pain intensities seemed to discriminate better between treatments, and the efficacy of acetaminophen was weakly dependent on the initial pain intensity. This intensity was difficult to predict, and only a poor correlation was found between the initial pain intensity and the patient's prior estimate of this.

One of a series of patients with extremely resorbed maxillae treated with bone grafts from the hip in combination with Brånemark self-tapping fixtures died in a car accident 4 months after implant surgery. Autopsy specimens from this patient were analyzed to evaluate the amount and extent of "osseointegration" after 4 months of healing. Histologic examination revealed that minimal bone was in direct contact with the titanium and the general pattern was that of soft tissue screw anchorage. There were no signs of sequestering of the transplanted bone. The connection between the nasal cavity and the sinus mucosa with respect to the transplants seemed to be without adverse reactions. The superior part of the transplant did show signs of newly formed bone. The grafted specimens showed indications of delayed bone response compared to the nongrafted situation. All implants were clinically stable as studied postmortem.

A combination of horseshoe-shaped iliac bone grafts and Brånemark implants was used in 30 patients with severely resorbed maxillary alveolar ridges. All patients were followed clinically for 2 years and evaluated with regard to prosthesis stability, fixture survival, wound healing complications, and soft tissue conditions. Surgery was performed by the same oral surgeons using identical procedures, and the prosthetic treatment was performed by the same prosthodontist. The development group included the first 10 patients and the routine group included the following 20. Fixture survival in the development group was 54.4%, whereas 88.3% of the fixtures in the routine group have survived after 2 years. The average fixture survival in the study was 77.4%. Three patients in the development group lost all fixtures, primarily the result of trauma to the grafted region. With respect to the difficult situation many of these patients experienced, the survival rate should be considered most acceptable.

Combined horseshoe-shaped iliac bone grafts and Brånemark fixtures were used to rehabilitate patients with severely resorbed maxillae. Twenty patients were followed-up by computed tomography (CT) examination with axial slices to assess the fixture sites and to study the changes in height and width of the bone graft 3 weeks and 3, 6, 12, and 24 months postoperatively. The mean height of the bone graft at the 3-week postoperative examination was 8.2 mm; after 2 years the mean value had decreased to 6.2 mm. The height reduction occurred mainly between the 3-month and 1-year examinations. The mean width of the bone graft at the 3-week postoperative examination was 12.2 mm, and it decreased to 8.6 mm after 2 years. Most of the width reduction took place during postoperative months 1-3. From 1 year after the grafting procedure, the rate of reduction of both height and width was very low.

This study presents the results from ten consecutive patients who, because of insufficient bone volume for conventional implant placement in the maxilla, were treated with an interpositional bone graft and Le Fort I osteotomy. The endosteal implants were placed six months after the osteotomy. A total of 60 screw-shaped titanium implants (Brånemark) were placed, of which three failed to integrate during the six-month healing period. No further implants were lost during the follow-up period, ranging from 15 to 39 months after placement of the implants. All patients received fixed bridges and all have continued to function efficiently.

Treatment of the atrophic edentulous maxilla is challenging especially when bone graft procedures are necessary. In this study an onlay bone graft, a saddle or veneer, with or without maxillary sinus floor inlay graft, harvested from the anterior iliac crest, in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. The aim was to investigate treatment outcome, and the impact of gender and smoking, in 44 patients in a prospective, long-term, follow-up study concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. Mean follow-up time was 11 years. Of 334 inserted Brånemark implants, with machined surface, 27 failed. Estimated implant survival rate was 90%. Marginal bone loss was 1.8 mm 1 year after implant surgery; 2.3 mm after 5 years; and 2.4 mm after 10 years. There was a significant difference between genders in implant survival. Marginal bone loss differed significantly between smokers and non-smokers up to the 5-year examination and between genders after the 4-year examination. The onlay bone graft, with or without a maxillary inlay graft, results in high implant survival rate, good oral function and stabilised marginal bone. All patients are still wearing their original fixed bridges.

A Le Fort I osteotomy and interpositional bone graft in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. Surgery was performed in a two-stage procedure. The patients in this study had conditions with reversed intermaxillary relationships with or without increased vertical intermaxillary distance. The aim of the study was to investigate treatment outcome for patients in a prospective, long-term, follow-up with a mean of 13 years (range 11-16 years), concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. The impact of gender and smoking was also investigated. Twenty-six patients were included in the study. Of 167 implants, 24 failed. The implant estimated survival rate was 85% at the end of the follow-up. There was no significant difference between smokers and non-smokers or genders concerning implant survival. Marginal bone loss was 2.5, 2.9, 3.0 and 3.1mm from the implant-abutment junction, after 1, 2, 5 and 10 years, respectively. The bone level stabilised after 2 years. This technique results in good facial morphology, good oral function and aesthetics. All patients are still wearing their original fixed bridges.