Immediate Implantation in Fresh Extraction Sockets
Immediate Implantation in Fresh Extraction Sockets. A Controlled Clinical and Histological Study in Man
Michele Paolantonio et al.
Background: Early implantation may preserve the alveolar anatomy, and the placement of a fixture in a fresh extraction socket helps to maintain the bony crest. Although a number of clinical studies exist, no histological reports show the outcome of implantation in fresh extraction sockets without the use of membranes in humans compared to implants placed in mature bone.
Methods: Forty-eight healthy patients, receiving at least 4 fixtures in each of 2 symmetrical quadrants, underwent placement of 1 experimental fixture placed in a fresh extraction socket (TI) and 1 contralateral fixture in mature bone (CI). TI were placed after atraumatical tooth extraction, with a surgical site at the apex of the socket and a tight contact between the fixture and the socket?s walls, but without the use of filling materials or membranes. The flap was coronally repositioned to obtain primary wound closure. Immediately after surgical intervention, a standardized periapical radiograph was taken. Second-stage surgery was done after 6 months. Six months after the second surgery, a second standardized periapical radiograph was taken and clinical parameters (bleeding and plaque index) recorded. Marginal bone loss (MBL) from the time of implant placement to the time of fixture removal was calculated by comparing periapical radiographs. TI and CI were then removed by a hollow drill to obtain histological specimens. Non-demineralized sections were stained by acid fuchsin and toluidine blue, and by von Kossa to evaluate the degree of bone mineralization. The percentage of direct implant-bone contact (DBC) was calculated by a computerized microscopic digitizer.
Results: No significant differences in the clinical and radiographic parameters were observed between the 2 experimental categories. There was no statistically significant difference between TI and CI for DBC either in the maxilla or in the mandible. No connective or fibrous tissues were present around TI or CI. Bone resorption was not present in any of the histological sections.
Conclusions: The present study shows that when a screw-type dental implant is placed without the use of barrier membranes or other regenerative materials into a fresh extraction socket with a bone-to-implant gap of 2 mm or less, the clinical outcome and degree of osteointegration does not differ from implants placed in healed, mature bone. J Periodontol 2001;72:1560-1571.
Bucco-Lingual Crestal Bone Changes After Immediate and Delayed Implant Placement
Ugo Covani et al.
Background: Implants placed immediately after tooth extraction offer several advantages, but many authors have reported problems in filling the residual gap between the implant and the socket walls. Barrier and grafting techniques have been tested and yield varying results, so it has been suggested that the timing of implant placement may be important for success. The aim of this study was to analyze bone healing and coronal bone remodeling around 35 implants, 20 placed immediately after tooth removal and 15 placed 6 to 8 weeks after extraction.
Methods: All the implants were submerged and placed within the alveoli confines, leaving circumferential defects because the implants did not contact the bone at their coronal aspects; stabilization was achieved in the bone apically. After implant placement the mean distance from buccal bone to lingual bone was 10 mm (SD 1.522) for immediate implants and 8.86 mm (SD 2.356) for delayed implants. No membrane or filling materials were used. Primary flap closure was accomplished in all cases.
Results: At second-stage surgery all peri-implant defects were filled, and the mean distance from buccal bone to lingual bone was 8.1 mm (SD 1.334) for immediate implants and 5.8 mm (SD 1.265) for delayed implants. This pattern of coronal bone remodeling, showing a narrowing of the bucco-lingual width, was clinically similar for the two groups, although it should be noted that the delayed implants exhibited smaller bucco-lingual bone width already at the first measurement: it can be speculated that early remodeling may start immediately after tooth extraction and continue, non-uniformly, even after delayed implant placement.
Conclusions: This study suggests that circumferential defects could heal clinically without any guided bone regeneration (GBR) in both experimental groups, and that the procedure was virtually free from complications in the postoperative period, probably because of the absence of barrier membranes and/or grafting materials. Histologically, periimplant defects of over 1.5 mm heal by connective tissue apposition, rather than by direct bone-to-implant contact, but clinically this healing may be very successful. No histological analysis was carried out in the present study, but even the largest residual gaps were filled with hard tissue that could not be probed. Thus, such outcomes can be considered clinically successful. The different rate of bone remodeling around immediate or delayed implants could have implications for the preferred timing of implant placement in sites of high esthetic concern. J Periodontol 2004;75:1605-1612.
Michele Paolantonio et al.
Background: Early implantation may preserve the alveolar anatomy, and the placement of a fixture in a fresh extraction socket helps to maintain the bony crest. Although a number of clinical studies exist, no histological reports show the outcome of implantation in fresh extraction sockets without the use of membranes in humans compared to implants placed in mature bone.
Methods: Forty-eight healthy patients, receiving at least 4 fixtures in each of 2 symmetrical quadrants, underwent placement of 1 experimental fixture placed in a fresh extraction socket (TI) and 1 contralateral fixture in mature bone (CI). TI were placed after atraumatical tooth extraction, with a surgical site at the apex of the socket and a tight contact between the fixture and the socket?s walls, but without the use of filling materials or membranes. The flap was coronally repositioned to obtain primary wound closure. Immediately after surgical intervention, a standardized periapical radiograph was taken. Second-stage surgery was done after 6 months. Six months after the second surgery, a second standardized periapical radiograph was taken and clinical parameters (bleeding and plaque index) recorded. Marginal bone loss (MBL) from the time of implant placement to the time of fixture removal was calculated by comparing periapical radiographs. TI and CI were then removed by a hollow drill to obtain histological specimens. Non-demineralized sections were stained by acid fuchsin and toluidine blue, and by von Kossa to evaluate the degree of bone mineralization. The percentage of direct implant-bone contact (DBC) was calculated by a computerized microscopic digitizer.
Results: No significant differences in the clinical and radiographic parameters were observed between the 2 experimental categories. There was no statistically significant difference between TI and CI for DBC either in the maxilla or in the mandible. No connective or fibrous tissues were present around TI or CI. Bone resorption was not present in any of the histological sections.
Conclusions: The present study shows that when a screw-type dental implant is placed without the use of barrier membranes or other regenerative materials into a fresh extraction socket with a bone-to-implant gap of 2 mm or less, the clinical outcome and degree of osteointegration does not differ from implants placed in healed, mature bone. J Periodontol 2001;72:1560-1571.
Bucco-Lingual Crestal Bone Changes After Immediate and Delayed Implant Placement
Ugo Covani et al.
Background: Implants placed immediately after tooth extraction offer several advantages, but many authors have reported problems in filling the residual gap between the implant and the socket walls. Barrier and grafting techniques have been tested and yield varying results, so it has been suggested that the timing of implant placement may be important for success. The aim of this study was to analyze bone healing and coronal bone remodeling around 35 implants, 20 placed immediately after tooth removal and 15 placed 6 to 8 weeks after extraction.
Methods: All the implants were submerged and placed within the alveoli confines, leaving circumferential defects because the implants did not contact the bone at their coronal aspects; stabilization was achieved in the bone apically. After implant placement the mean distance from buccal bone to lingual bone was 10 mm (SD 1.522) for immediate implants and 8.86 mm (SD 2.356) for delayed implants. No membrane or filling materials were used. Primary flap closure was accomplished in all cases.
Results: At second-stage surgery all peri-implant defects were filled, and the mean distance from buccal bone to lingual bone was 8.1 mm (SD 1.334) for immediate implants and 5.8 mm (SD 1.265) for delayed implants. This pattern of coronal bone remodeling, showing a narrowing of the bucco-lingual width, was clinically similar for the two groups, although it should be noted that the delayed implants exhibited smaller bucco-lingual bone width already at the first measurement: it can be speculated that early remodeling may start immediately after tooth extraction and continue, non-uniformly, even after delayed implant placement.
Conclusions: This study suggests that circumferential defects could heal clinically without any guided bone regeneration (GBR) in both experimental groups, and that the procedure was virtually free from complications in the postoperative period, probably because of the absence of barrier membranes and/or grafting materials. Histologically, periimplant defects of over 1.5 mm heal by connective tissue apposition, rather than by direct bone-to-implant contact, but clinically this healing may be very successful. No histological analysis was carried out in the present study, but even the largest residual gaps were filled with hard tissue that could not be probed. Thus, such outcomes can be considered clinically successful. The different rate of bone remodeling around immediate or delayed implants could have implications for the preferred timing of implant placement in sites of high esthetic concern. J Periodontol 2004;75:1605-1612.
posted by Ajou Huang | 7:27 PM
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