Biomedical subjects

Lars Sennerby

Publications and source records attributed to Lars Sennerby.

36 records · Page 2Linked to original sources

PubMed2004

Bone reformation with sinus membrane elevation: a new surgical technique for maxillary sinus floor augmentation.

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.

Blood Coagulation↗

PubMed2003

Influence of preimplant surgical intervention and implant placement on bone wound healing.

The aims of the present investigation were to study (1). the influence of preimplant (4 weeks) surgical intervention and (2). the influence of the implant placement per se on bone density and mineralized bone-implant contact (BIC) at implant sites in the rabbit jawbone. The experiment was performed in the edentulous area of the maxillas of 16 adult rabbits. In eight rabbits, the alveolar bone on the left side (test) was surgically exposed and a groove was prepared in the bone crest. Trabecular bone and marrow tissue were removed, and a bioabsorbable barrier membrane was placed to cover the groove. The right side underwent no treatment and served as the control. Four weeks later, a screw-shaped titanium implant was placed transversally through the maxilla, penetrating both the test and the control areas. After another 4 weeks of healing, the animals were killed to obtain ground sections for histomorphometry. Untreated jaws from eight rabbits served as reference specimens. In the rabbits subjected to surgery, the areas (mm2) of both mineralized bone and marrow tissue were similar for test and control (4.9 +/- 1.7 vs. 5.1 +/- 2.2 and 6.3 +/- 5.7 vs. 6.8 +/- 5.7 for bone and marrow, respectively). The BIC (%) for all threads was significantly lower on the test side than on the control side (32.1 +/- 27.7 vs. 47.7 +/- 20.3). The bone density (%) of the total experimental area was similar for test and control (48.5 +/- 12.1 vs. 46.5 +/- 9.3), as was the bone density in the area within the implant thread valleys and their mirror areas (43.0 +/- 13.9 vs. 41.3 +/- 13.5, and 40.2 +/- 11.0 vs. 40.3 +/- 7.2 for thread area and mirror area, respectively). The bone density of the total experimental area in the untreated rabbits was 35.9 +/- 5.2%. This value was significantly lower than the values in the total experimental areas (test and control) of the surgically treated rabbits. Similarly, the density of the reference area in the untreated rabbits was 25.4 +/- 5.3%, which was also significantly lower than the bone density of the periimplant area of the surgically treated rabbits. We conclude that the surgical trauma caused by the placement of implants in the maxilla of rabbits significantly enhanced the bone density of the implant sites. Surgical intervention in the implant sites 4 weeks prior to the implant placements, however, did not further enhance bone density or BIC.

Analysis of Variance↗

PubMed2003

Some soft tissue characteristics at implant abutments with different surface topography. A study in humans.

BACKGROUND: : If an implant with a rough surface is exposed to the oral cavity, it may accumulate greater amounts of plaque than a smooth surface, which may lead to severe problems with mucositis and peri-implantitis. The purpose of the present paper was to investigate the early inflammatory response to mucosa-penetrating abutments prepared with varying surface roughness. METHODS: : Nine patients had all five of their original abutments exchanged to test abutments for a 4-week period. The test abutments were prepared with five different roughnesses. The surface roughness was measured with an optical profilometer. At the end of the test period, clinical evaluation was performed; the health of the surrounding mucosa, the amount of accumulated plaque and marginal bleeding were registered. One biopsy was taken from each test abutment. Qualitative and quantitative histological evaluations were performed. RESULTS: : There was a statistically significant difference between patients regarding the amount of accumulated plaque on the abutment surfaces and inflammatory cells, but no difference between the surface modifications in relation to plaque accumulation or number of inflammatory cells. CONCLUSION: : No relation was found between inflammatory response and abutment surface roughness after an evaluation time of 4 weeks in a human test model.

Aluminum Oxide↗

PubMed2003

Immediate occlusal loading of Brånemark TiUnite implants placed predominantly in soft bone: 1-year results of a prospective clinical study.

BACKGROUND: The original Brånemark protocol for dental implant treatment was based on submerged healing prior to loading. However, immediate loading has been reported possible with high success rates for various indications, provided that good bone quality and quantity are present. In many of these studies, machined-surface implants have been used. Recently, a new surface texture has been developed, based on an oxidation processing, that aims to enhance the early bone response (Brånemark System Mk IV TiUnite , Nobel Biocare AB, Gothenburg, Sweden). It has been documented that this surface texture may help to better maintain primary implant stability during the early healing period and that secondary implant stability can be reached earlier compared with results when using a machined surface. Such a positive influence on implant stability might be an advantage when applying an immediate-loading protocol, especially in soft bone regions where a tendency toward reduced success rates has been reported. PURPOSE: The aim of this report was to present the short-term success rates of TiUnite-surfaced immediate occlusally loaded Brånemark System Mk IV implants placed in various regions of the jaws. MATERIALS AND METHODS: Thirty-eight patients received a total of 51 prosthetic reconstructions, all of which were connected on the day the implants were inserted. Of these, 20 were single-tooth restorations, 30 were fixed partial dentures, and 1 was a complete fixed lower jaw restoration. These prostheses were supported by 102 Brånemark System Mk IV TiUnite implants (38 maxillary and 64 mandibular), the majority of which were placed in posterior regions (88%) and mainly in soft bone (76%). Cutting resistance measurements were performed during implant insertion, and resonance frequency measurements were conducted during the course of the study. Furthermore, radiographic examinations were performed in connection with the delivery of the prostheses and at the 1-, 6-, and 12-month follow-up visits. This article reports on the results after 1 year of loading. RESULTS: Three maxillary implants were removed, although stable, in one patient at the 8-week follow-up because of postoperative infection in the adjacent area of guided bone regeneration (GBR). This resulted in a cumulative success rate of the implants of 97.1% after 1 year of prosthetic loading. The mean marginal bone resorption after 1 year of loading was 1.2 +/- 0.9 mm (SD). CONCLUSIONS: The applied immediate loading protocol in combination with a slightly tapered implant and a modified implant surface texture was shown to be a successful treatment alternative even in regions exhibiting soft bone.

Adult↗

PubMed2003

Early loading of maxillary fixed cross-arch dental prostheses supported by six or eight oxidized titanium implants: results after 1 year of loading, case series.

BACKGROUND: Recent reports have demonstrated that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for two-stage procedures, at least in good bone qualities. However, documentation of the outcome of immediate/early loading in the totally edentulous maxilla is scarce. PURPOSE: The present investigation was undertaken to evaluate the outcome over 1 year of oxidized titanium implants when loaded with a fixed full-arch bridge in the maxilla 1 to 9 days after implant placement. MATERIALS AND METHODS: Ten patients with totally edentulous maxillas were treated with 61 oxidized titanium implants, and a provisional fixed bridge was delivered after 1 to 9 days (mean 2.5 d). Nine patients had six implants and one patient had eight implants supporting the bridge. The provisional bridge was replaced with a permanent bridge after 2 to 7 months (mean 4.1 mo) of loading. Resonance frequency analysis (RFA) for implant stability measurements was made at implant placement in eight patients and in conjunction with permanent bridge connection in five patients. The patients were followed up for 1 year with clinical and radiographic examinations. RESULTS: Four implants (6.6%) were lost in one patient after 10 weeks of loading owing to an infection. All other implants were clinically stable with a mean marginal bone loss of 1.3 +/- 0.6 mm after 1 year of loading. RFA showed a mean primary stability of 60.1 +/- 3.6 ISQ (implant stability quotient), which increased to 62.8 +/- 1.6 ISQ after, on average, 4 months. CONCLUSIONS: The results from this limited study on 10 cases indicate that early loading protocols can be applied for cross-arch dental bridges supported by six to eight implants in the maxilla. However, more clinical trials are needed to establish the long-term predictability of the treatment.

Aged↗

PubMed2003

Histology of retrieved immediately and early loaded oxidized implants: light microscopic observations after 5 to 9 months of loading in the posterior mandible.

BACKGROUND: An increased number of publications report that one-stage surgery and immediate/early loading of dental implants may be a feasible approach for prosthetic reconstruction of the edentate patient. However, little is known about the histologic response to implants subjected to immediate/early loading in patients. PURPOSE: The aim of the present study was to histologically evaluate oxidized titanium implants subjected to loading immediately following surgery or after 2 months of healing and removed after 5 to 9 months loading. MATERIALS AND METHODS: Five patients participated in the study; each had consulted for implant treatment in the posterior mandible and subsequently volunteered to have extra implants inserted for the purpose of histologic research. Nine oxidized titanium implants (Brånemark System TiUnite , Nobel Biocare AB, Gothenburg, Sweden) were retrieved after 5 to 9 months in function. Two implants had been loaded the same day, whereas seven implants were loaded after 2 months of healing. Resonance frequency analysis was performed at retrieval on seven implants. Ground sections were prepared for histology and analyzed using light microscopic morphometry. RESULTS: Seven and 8.5 mm implants were placed, predominantly in quality 3 and 4 bone. Four implants were straight (Mk III), and five were tapered (Mk IV). All implants were clinically stable at retrieval and showed ISQ values of 65 to 79 with a mean of 71.4 +/- 4.4. Eight of the implants were able to be used for histology. A gross histologic examination showed an undisturbed healing of soft and bone tissues with no apparent differences between response to immediately and early loaded implants. Lamellar bone surrounded the implants, and remodeling was evident and more marked near the implant surface. A condensation of bone toward the implant surface was seen; this resulted in a lamina dura-like structure in trabecular bone. Thin rims of newly formed bone were often seen following the contour of the implant surface. The morphometric measurements showed a mean bone-to-implant contact value of 84.2 +/- 10.5% and a mean bone area value of 79.1 +/- 6.8%. The two immediately loaded implants showed bone-to-implant contact and bone area values of 92.9 +/- 0.1% and 84.9 +/- 0.9%, respectively. The corresponding values for the six early loaded implants were 81.4 +/- 10.6% and 77.1 +/- 6.8%, respectively. CONCLUSIONS: The present study demonstrated that oxidized implants subjected to immediate or early loading do integrate with soft and bone tissues in the posterior mandible.

Adult↗

PubMed2003

Immediate/early loading of dental implants: a report from the Sociedad Española de Implantes World Congress consensus meeting in Barcelona, Spain, 2002.

BACKGROUND: Immediate/early loading protocols are becoming frequently used in implant dentistry, but the prerequisites for achieving good results and the limitations of such protocols are not fully known. Moreover, the terminology used in immediate/early loading is still confusing. PURPOSE: The purpose of this article is to present the outcome of a consensus meeting on immediate/early loading. MATERIALS AND METHODS: A consensus meeting was organized during the Sociedad Española de Implantes World Congress in Barcelona on May 23, 2002, with the objective to present and discuss the experiences from immediate/early loading protocols in dental implant treatment. The purpose was also to discuss definitions of the terminology used in immediate/early loading. The consensus meeting agenda included presentations from invited experts, followed by a consensus discussion. RESULTS: A consensus statement was agreed on. CONCLUSIONS: Multiple independent investigators have demonstrated that immediate/early loading of implants is possible in many clinical situations; however, additional documentation is required.

Dental Implantation, Endosseous↗

PubMed2003

One-year prospective three-center study comparing the outcome of a "soft bone implant" (prototype Mk IV) and the standard Brånemark implant.

BACKGROUND: Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry. PURPOSE: The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Brånemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone. MATERIALS AND METHODS: Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare), Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year. RESULTS: The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants. CONCLUSIONS: The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested.

Adult↗

PubMed2003

Spontaneous bone formation in the maxillary sinus after removal of a cyst: coincidence or consequence?

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.

Adult↗

PubMed2003

Surgical intervention in enchondral and membranous bone: intraindividual comparisons in the rabbit.

BACKGROUND: The long bones, which are of enchondral origin, are often used in histologic evaluations of dental implants that clinically will be placed in bones of membranous origin. PURPOSE: The aim of this investigation was to study the effect of surgical trauma by multiple drill perforations on both enchondral and membranous bone--the tibial and maxillary bone architecture--8 weeks after surgery. MATERIALS AND METHODS: In eight rabbits the medial metaphyses of both tibiae and the edentulous ridges of both sides in the maxilla were surgically exposed. On the test sides, 25 to 30 holes were drilled through the cortical plate and 5 mm into the medullary space. The contralateral sides underwent no treatment and served as controls. Eight weeks later the animals were killed to obtain transverse ground sections for histomorphometry. A paired analysis of the bone densities of the tibiae and the jaw specimens was made. RESULTS: In general the morphologic appearances of the test and control tibiae were similar. In the control group the anatomy of the medullary space appeared normal, with few bone trabeculae and with abundant marrow tissue. In the test group, areas of resorption were evident on the cortical bone plate that had been perforated 8 weeks previously; also evident were ingrowths of marrow tissue and bone formation. In a few specimens some newly formed bone trabeculae were found in the medullary space, both contiguous to the perforated cortical bone plate and as small islets in the marrow tissue. The mean test and control site values for each parameter were similar, and no statistically significant differences were found. In the maxilla, the bone architecture had altered substantially by way of an increase in the proportion of trabecular bone and a decrease in the proportion of cortical bone. Drilling appeared to have little effect on tibial bone density, which did not significantly differ between test and control sites. Maxillary bone density, however, was significantly greater at the test sites than at the control sites. Comparisons of bone density between tibia and jaw specimens revealed no significant differences either between test sides or between control sides. Thus, the same magnitude of surgical trauma that altered the bone architecture and density of the rabbit maxilla was not found to have altered those of the tibia in the same animal 8 weeks after surgery. The reasons for the differences are discussed in this article. CONCLUSIONS: As observed 8 weeks post surgery, multiple drill perforations were not found to cause significant alterations in the metaphysis of the tibia whereas a considerable change in bone architecture and an increase in bone density were found in the maxilla. Whether this depends on different embryologic origins or reflects morphologic and functional differences in the mature bone demands further study.

Animals↗

PubMed2002

The effect of titanium surface roughness on the adhesion of monocytes and their secretion of TNF-alpha and PGE2.

Dental implant surfaces are important in determining the tissue/surface interaction. One of the first cells to adhere to the implant surface is the monocyte. This study examines the effect of surface roughness on monocyte adhesion and cytokine secretion. Monocyte adherence to titanium discs of 4 different degrees of surface roughness and plastic surfaces was assayed. Blood mononuclear cells were incubated for 1.5 h in 16 mm culture wells into which titanium discs had been placed. Non-adherent cells were washed off and the numbers of remaining adherent monocyte determined by DNA quantification. TNF-alpha and PGE2 secretion in media from overnight cultures of attached monocytes stimulated with lipopolysaccharide (LPS) was quantified using ELISA and RIA, respectively. Monocyte adherence to rough titanium surfaces was greater than to turned titanium surfaces, while the lowest adherence was to the plastic surface. No significant differences in adherence to 250, 75 or 25 microm blasted surfaces could be detected. The number of adherent monocytes increased with time, with maximum adhesion after 2 h of incubation. Incubation of monocytes adherent to titanium surfaces resulted in a decrease of less than 30% in their numbers over 7 days, whereas cells attached to plastic surfaces decreased to non-detectable numbers after 48 h. Porphyromonas gingivalis LPS stimulation upregulated TNF-alpha and PGE2 secretion into the media. The LPS-induced TNF-alpha and PGE2 secretion was independent of the titanium surface roughness, however the lowest amounts of TNF-alpha and PGE2 were secreted from cells attached to plastic surfaces. The results of this study indicate that the number of monocytes attached to blasted titanium surfaces is significantly greater than to machined titanium surfaces. PGE2 and TNF-alpha secretion is less influenced by titanium surface roughness.

Analysis of Variance↗

PubMed2002

A prospective 1-year clinical and radiographic study of implants placed after maxillary sinus floor augmentation with bovine hydroxyapatite and autogenous bone.

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.

Aged↗

PubMed2002

Clinical and histologic findings for microimplants placed in one stage and loaded for three months: a case report.

BACKGROUND: Implants are placed in either one or two stages. There is an absence of histologic human evidence relating to implant integration after loading. PURPOSE: The purpose of this case report was to present clinical and histologic findings for smooth-surfaced titanium turned microimplants placed in one stage and loaded after healing. MATERIALS AND METHODS: Five one-piece microimplants were placed in a fully edentulous mandible. Three microimplants (tests) were placed in one stage and extended through the keratinized mucosa for 3 mm. Two additional microimplants (controls) were placed even with the mucosa. After 3 months of healing, three test implants were loaded for an additional 3 months. At this time, three loaded implants and one control were removed en bloc. RESULTS: Histologic and histometric evaluations were made. For all specimens, there was excellent bone-to-implant contact. The loaded implants had from two to four exposed threads. Using marginal bone levels as the reference, the highest percentage of bone-to-implant contact was noted with the unloaded control implant (92.2%). One nonaxially loaded implant had 66.9% bone-to-implant contact, whereas the axially loaded implants (n = 2) had 77.8% bone-to-implant contact. CONCLUSIONS: Within the limits of this case report, smooth-surfaced, titanium threaded microimplants placed in one stage and loaded for 3 months demonstrated excellent osseointegration, with varying bone-to-implant contact. The amount of bone-to-implant contact may be related to axial implant loading.

Bone Remodeling↗

PubMedDate not supplied

A clinical and histologic evaluation of implant integration in the posterior maxilla after sinus floor augmentation with autogenous bone, bovine hydroxyapatite, or a 20:80 mixture.

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.

Absorbable Implants↗

PubMedDate not supplied

Clinical outcome of Brånemark System implants of various diameters: a retrospective study.

PURPOSE: The purpose of this study was to evaluate the outcome of the 3 different diameters of Brånemark System implants, with special focus on the 5.0-mm-diameter implant. MATERIALS AND METHODS: Ninety-eight patients (99 jaws) with a mean age of 62 years were included in this retrospective report. The mean follow-up period was 2 years and 8 months. A total of 379 Brånemark System implants (3.75 mm diameter, n = 146; 4.0 mm diameter, n = 76; 5.0 mm diameter, n = 157) were placed in 29 edentulous and 70 partially edentulous jaws. RESULTS: Eight of the 146 implants in the 3.75-mm-diameter group failed (5.5%). The corresponding figures for the 4.0- and 5.0-mm-diameter implants were 3 of 76 (3.9%) and 7 of 157 (4.5%), respectively. DISCUSSION: All failures were recorded in maxillae, ie, 18 of the 298 placed, and the majority of these were found in bone quantity group B and quality group 2. Only 3 implants of 131 failed in bone judged as quality 4. The marginal bone loss was low for the 3 implant diameter groups. CONCLUSION: The favorable outcome in bone of poor quality is ascribed partly to the use of an adapted preparation technique and extended healing periods for achievement of the best primary and secondary implant stability possible.

Alveolar Bone Loss↗

PubMedDate not supplied

Survival analysis of endosseous implants in grafted and nongrafted edentulous maxillae.

PURPOSE: The aim of this study was to analyze and compare the survival rates of endosseous implants placed in the edentulous maxillae of patients in whom bone augmentation was undertaken prior to or in conjunction with implant placement with survival rates in patients who did not undergo bone augmentation. MATERIALS AND METHODS: This study included 2 retrospective patient groups: the graft group, which included 64 patients with 437 implants, and the nongraft group, which included 118 patients with 683 implants. The patients were treated consecutively between 1990 and 1996. In addition, the retrospective patient groups were also followed prospectively using a standardized clinical and radiographic study design. RESULTS: The implant survival rate was 75.1% for the graft group and 84.0% for the nongraft group after a mean follow-up of 5 to 6 years, a statistically significant difference. However, there was no difference with regard to the prosthesis survival rate, and after reoperation, more grafted patients had a fixed prosthesis at the end of the study (87.5% versus 85.3%). Implant failure appeared to be related to the original jawbone volume in the anterior regions. In the premolar region, where the inlay graft technique was used, the implant survival rate for the graft group was comparable to that of the nongraft group. The graft group had significantly more failures than the nongraft group in the incisor region, but not in the canine, premolar, or molar regions. DISCUSSION: The majority of implant failures occurred before loading. Occlusal overload during the healing period may have been a causative factor. CONCLUSIONS: The overall implant survival rate was lower in grafted maxillae than in nongrafted maxillae after a mean of 5 to 6 years of follow-up. Analysis revealed that jawbone volume in the anterior regions at the start of treatment was directly related to implant survival rates in both groups: the greater the volume, the higher the survival rate. Moreover, the implant survival rate was similar in grafted posterior edentulous maxillae of classes V and VI and in nongrafted posterior edentulous maxillae of classes III and IV.

Adult↗

PubMedDate not supplied

Resonance frequency analysis measurements of implants at placement surgery.

PURPOSE: The knowledge of what levels of primary stability can be obtained in different jawbone regions and of what factors influence primary stability is limited. The objective of this study was to evaluate primary stability by resonance frequency analysis (RFA) measurements of implants placed according to a surgical protocol that aimed for high primary stability. The aim was also to correlate RFA measurements with factors related to the surgical technique, the patient, and implant design. MATERIALS AND METHODS: A total of 905 Brånemark dental implants used in 267 consecutive patients were measured with RFA at the time of placement surgery. RESULTS: A mean ISQ value of 67.4 (SD 8.6) was obtained for all implants. Univariate analyses with the implant or patient as unit showed higher ISQ values in men compared with women, in mandibles compared with maxillae, in posterior compared with anterior sites, and for wide-platform implants in comparison with regular/narrow-platform implants. There was a correlation between bone quality and primary stability, with lower ISQ values obtained for implants placed in softer bone. A lower stability was seen with increased implant length. A stepwise multiple regression analysis using the patient as unit showed that jaw type and gender had independent effects on primary stability. CONCLUSION: The results suggest that factors related to bone density and implant diameter/length may affect the level of primary implant stability. Furthermore, greater stability was observed in male than in female patients. High primary implant stability was achieved in all jaw regions, although the use of thinner drills and/or tapered implants cannot fully compensate for the effect of soft bone. The research design does not permit conclusions regarding long-term treatment outcome with implants.

Aged↗

PubMedDate not supplied

A histomorphometric comparison of the bone graft-titanium interface between interpositional and onlay/inlay bone grafting techniques.

PURPOSE: To analyze the bone graft-implant interface of titanium microimplants (MIs) placed at the time of bone grafting or after a healing period of 6 months and retrieved after another 6 to 14 months of healing. Integration of MIs placed in interpositional bone grafts (IBGs) in conjunction with a Le Fort I osteotomy was compared with the integration of those placed in onlay/inlay bone grafts (OBGs). MATERIALS AND METHODS: The severely atrophied edentulous maxillae of 23 patients (14 women, 9 men) were restored with autogenous bone grafts (either IBG [n=8] or OBG [n=15]) and titanium implants. Six-month periods were allowed between grafting, implant placement, and abutment connection. The bone-implant interface was studied histologically with the use of unloaded titanium MIs. RESULTS: Sixty-eight MIs were either (1) placed simultaneously with grafting and retrieved after 6, 12, or 14 months or (2) placed after 6 months of healing and retrieved after another 6 to 8 months. Histomorphometry indicated equal degrees of osseointegration for the 2 intraoral reconstruction techniques when looking at bone-implant contact, bone area in threads, and newly formed bone (NFB) (Student t test for unpaired observations). There was a significant difference between simultaneous and delayed implant placement with respect to BIC and NFB (Student t test for paired observations). Three additional MIs placed in the nongrafted residual alveolar ridge and retrieved after 6 months showed significantly more bone in threads and NFB (Student t test for paired observations; P = .003 and P = .009, respectively) compared to MIs placed at graft placement (6 months' healing). DISCUSSION: Timing of implant placement appeared more important than healing time or surgical technique. The delayed approach resulted in better implant integration, probably because of the initial revascularization of the graft. CONCLUSIONS: Implant integration was similar in the IBG and OBG groups. Placement of MIs after an initial healing period of 6 months resulted in better integration than placement simultaneously with grafting.

Adult↗