| 1. |
- Becker, W, et al.
(författare)
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Histologic findings after implantation and evaluation of different grafting materials and titanium micro screws into extraction sockets: case reports.
- 1998
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Ingår i: Journal of periodontology. - : Wiley. - 0022-3492 .- 1943-3670. ; 69:4, s. 414-21
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to compare extraction socket healing in 8 patients after implantation with either xenogenic bovine bone (n=5 sites), demineralized freeze-dried bone (DFDBA) (n=3 sites), autologous bone (n=3 sites), or human bone morphogenetic proteins in an osteocalcein/osteonectin carrier (hBMP/NCP) (n=2 sites). Three of the patients received 6 commercially pure micro screws which were fixed into extraction sockets, after which the sockets were implanted with either bovine bone (n=3 sites), DFDBA (n=2 sites) or intraoral autologous bone (n=1 site). Biopsies of the extraction sockets were taken from 3 to 6 months after treatment (average, 4.6 months). For comparison of healing between the implanted materials, histologic evaluation and bone scores were determined. Bone scores of 0 indicated an absence of new bone, with dead implanted bone particles entrapped within connective tissue, while a score of 3 indicated the entire field consisted of vital bone. Biopsies from bovine bone sockets revealed dead implanted particles surrounded by connective tissue. Isolated sections showed host bone in contact with the bovine bone particles. Bone scores ranged from 0 to 3. Biopsies from DFDBA-implanted sites revealed dead particles entrapped with dense connective tissue. The bone scores ranged from 0 to 1. Biopsies from sites implanted with hBMP/NCP revealed a combination of woven and lamellar bone with bone scores of 3. Five of the 6 micro screws were processed and evaluated. One screw was mobile at the time of removal and was not evaluated. Bone scores were used to compare new bone formation adjacent to the micro screws. Bone scores ranged from 0 to 2. A score of 0 indicated non-vital implant material in contact with host bone and connective tissue in contact with implant; 2 indicated vital bone in contact with the majority of the implant surface. Retrieved sockets with micro screws implanted with bovine bone (n=2) demonstrated a connective tissue interface between the screws and the surrounding tissues (bone score 0). The adjacent tissues showed dead bovine particles entrapped within fibrous tissue. Retrieved screws implanted with DFDBA (n=2) were surrounded by connective tissue, with dead bone particles enmeshed within fibrous tissue (bone score 0). The screw implanted with intra-oral autologous bone was primarily surrounded by vital bone with a connective tissue interface (bone score 1). Three implant threads were in contact with bone. The results of this study indicate that bovine bone, DFDBA, and intraoral autologous bone do not promote extraction socket healing. Sockets implanted with hBMP/NCP contained vital woven and lamellar bone. Xenogenic bovine bone and DFDBA did not contribute to bone to micro screw contacts and are not recommended for enhancement of vital bone to implant contacts. Intraoral autogenous bone also does not appear to significantly contribute to bone to implant contacts. Intraoral autologous bone, xenogenic bone, and DFDBA appear to interfere with normal extraction socket healing.
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| 2. |
- Dahlin, Christer, 1959, et al.
(författare)
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Histological morphology of the e-PTFE/tissue interface in humans subjected to guided bone regeneration in conjunction with oral implant treatment.
- 1998
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Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161. ; 9:2, s. 100-6
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present investigation was to study the histological morphology of the e-PTFE membrane/tissue interface in 5 humans subjected to GBR treatment in conjunction with oral implant treatment. Oral implants (Brånemark System) were inserted in extraction sockets 1 to 2 months after extraction of periodontally diseased teeth. The implants were placed approximately 2 mm below the surrounding bone margins. Specially designed 3 mm high cover-screws with horizontal slits for tissue ingrowth were applied to the implants and covered with e-PTFE membranes (GoreTex Augmentation Material). Re-entry was made 7 months later, except in 1 case where the membrane was removed 1 month postoperatively due to exposure and infection. In the remaining 4 sites, circular biopsies comprising membranes, tissues and cover-screws were retrieved. The specimens were fixated, processed and sectioned for light- and transmission electron microscopy. The space between the membrane and the cover-screw was occupied by fibrous tissue and varying amounts of bone. A cell- and vessel-rich fibrous tissue separated the bone from the membrane in the majority of the specimens. The membrane itself was penetrated by fibrous tissue. Fibroblasts and macrophages were the main cell types found in the fibrous tissue. The presence of irregularly shaped cells and unevenly distributed collagen fibres, indicated that the absence of bone formation may be due either to micromovements in the e-PTFE/tissue interface or to formation of fibrous tissue underneath the membrane by penetrating fibroblasts or a combination of these 2 phenomena.
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| 3. |
- Jensen, O T, et al.
(författare)
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Histologic analysis of clinically retrieved titanium microimplants placed in conjunction with maxillary sinus floor augmentation.
- 1998
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Ingår i: The International journal of oral & maxillofacial implants. - 0882-2786. ; 13:4, s. 513-21
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a new approach involving placement and subsequent retrieval of titanium microimplants was employed for the histologic investigation of the implant-tissue interface in conjunction with maxillary sinus floor augmentation. Nine patients scheduled for sinus floor augmentation and simultaneous placement of Brånemark implants were included in the study. After a sinus graft procedure and placement of implants, an additional microimplant was placed into the graft through the lateral wall of the sinus. At abutment connection, the microimplants were retrieved using a 3- or 5-mm-wide trephine drill. Six specimens were retrieved after 6 to 14 months from sites augmented with particulate radiated mineralized cancellous allograft. Another six implants were retrieved after 6 to 12 months from maxillary sinuses augmented with particulate autogenous bone grafts. The histologic analysis showed distinct differences between the two types of grafts. The sites with autogenous bones grafts displayed a normal morphology of bone and bone marrow, including formation of bone on the surfaces of the grafted particles and remodeling of newly formed as well as grafted bone. The bone was more mature after 11 to 14 months than at 6 months. The allografted sites had a mixed morphologic appearance of newly formed bone and nonviable allograft particles (about 75% of the total bone area) in loose connective tissue. Significantly more bone was found at the autografted than at the allografted implants. The use of autogenous bone for augmentation of the maxillary sinus floor resulted in a greater amount of viable bone surrounding the implant; however, simultaneous placement of implants apparently resulted in a low proportion of bone-implant contact after 6 to 14 months irrespective of graft type.
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| 4. |
- Meredith, N, et al.
(författare)
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Relationship between contact time measurements and PTV values when using the Periotest to measure implant stability.
- 1998
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Ingår i: The International journal of prosthodontics. - 0893-2174. ; 11:3, s. 269-75
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The Periotest is an electronic instrument that has been advocated for the measurement of implant stability and osseointegration. The aims of this investigation were to establish the relationship between contact time and PTV values when the Periotest was used to assess implants in vivo and in vitro, and to investigate the influence of the striking height of the Periotest handpiece and the length of implant abutment. MATERIALS AND METHODS: The accelerometer signal from a Periotest was captured and compared with the resulting PTV value. In vitro measurements of PTV and contract time were performed on a 3-mm abutment that had been attached to a 15-mm implant luted into an aluminium block, and were repeated on a patient in vivo. further measurements were made of the abutments of six implants in turn in the maxilla of the same patient. The standard abutment lengths on the implants were 3, 4 (x 2), 5.5 (x 2), and 7 mm. RESULTS: The results indicated that there was a linear relationship between contact time and PTV value for implants measured in vitro and in vivo. Greater scatter of the in vivo data was attributed to test and patient variables including striking position, distance, and damping as a result of the presence of soft tissue. There was a linear relationship between the PTV value and the striking height for implant measurements in vivo and in vitro. CONCLUSION: It can be concluded that the sensitivity of the Periotest to clinical variables including striking heights and handpiece angulation limit the application of the instrument as a clinical diagnostic aid to measure implant stability.
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| 5. |
- Sennerby, Lars, 1960, et al.
(författare)
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Resonance frequency analysis: measuring implant stability and osseointegration.
- 1998
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Ingår i: Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995). - 1548-8578. ; 19:5, s. 493-8, 500, 502; quiz 504
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Forskningsöversikt (refereegranskat)abstract
- Achievement and maintenance of implant stability are prerequisites for long-term positive outcomes for osseointegrated implants. Thus, implant stability is the key to clinical success. Until recently, it was not possible for the clinician to predictably distinguish implants with different degrees of stability. Because there seems to be a correlation between implant failure and bone properties, it is possible that clinically firms implants with poor stability are more prone to failure than more stable implants. This article discusses the development and possible future use of a novel technique for clinical measurement of implant stability and osseointegration--resonance frequency analysis.
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| 6. |
- Sennerby, Lars, 1960, et al.
(författare)
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Surgical determinants of clinical success of osseointegrated oral implants: a review of the literature.
- 1998
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Ingår i: The International journal of prosthodontics. - 0893-2174. ; 11:5, s. 408-20
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Forskningsöversikt (refereegranskat)abstract
- This article reviews the current knowledge about the influence of surgical factors on implant failure in routine cases and in those where implants have been used in conjunction with bone augmentation procedures.Clinical reports published in major scientific journals served as the basis for this review.With few exceptions, most clinical reports were on screw-shaped titanium implants. High failure rates are associated with poor bone quality and the use of short implants in the athrophic maxilla, irradiation, and bone-grafting procedures of the athrophic maxilla. Evidence for high long-term failure rates of press-fit cylinders was found. Moreover, limited clinical experience, lack of preoperative antibiotics, and smoking may lead to higher failure rates.There is a need for further research to increase the success rates in the severely resorbed maxilla. Because of a lack of proper documentation with respect to the great majority of currently used oral implant designs, the influence of different factors and their long-term results remain unknown.
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| 7. |
- Heo, S J, et al.
(författare)
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Stability measurements of craniofacial implants by means of resonance frequency analysis. A clinical pilot study.
- 1998
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Ingår i: The Journal of laryngology and otology. - : Cambridge University Press (CUP). - 0022-2151 .- 1748-5460. ; 112:6, s. 537-42
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Tidskriftsartikel (refereegranskat)abstract
- Nineteen patients previously treated with 52 implants for anchorage of craniofacial prostheses were subjected to implant stability measurements by means of resonance frequency analysis (RFA), six months to 15 years after implant placement. The resonance frequency (RF) of a transducer attached to the implant abutment was measured by using a frequency response analyser, a personal computer (PC) and dedicated software. Statistically significant higher RF values were seen for implants in the temporal bone as compared to implants in the nose and periorbital regions. There was a positive correlation with time since implant placement for the period from six months up to seven years. It was concluded that the preliminary results suggest that implant stability increases with time and that implants in temporal bone are more stable than implants in the bone in the nose and periorbital regions, probably reflecting differences in bone density.
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