Bone contact, growth, and density around immediately loaded implants in the mandible of mini pigs

Abstract

The aim of the study was to compare the bone mineral apposition rate (BMAR) of immediately loaded implants with an unloaded control during the early healing phase in the partially edentulous mandible. In seven mini pigs, three premolars and the first molar were removed in the left mandible. Three months later, five implants were installed. Four implants received a fixed provisional restoration and were loaded immediately. The most anterior implant was used as unloaded control. Polychromatic fluorescence labelling was performed to assess the BMAR. After 4 months, the implants were retrieved together with the adjacent bone. Histological specimens were prepared and subjected to a fluorescence microscopic and histomorphometric analysis. Two provisional restorations were found partially lost at the end of the observation period. One implant that had lost the splinting fixation showed soft connective tissue healing. The BMAR did not differ statistically significantly between loaded and unloaded implants and within the single groups during the observation period (BMARloaded days 14-42=1.8+/-0.2 microm/d, BMARloaded days 42-70=1.8+/-0.1 microm/d, BMARloaded days 70-98=1.6+/-0.1 microm/d, pBMARloaded days 14-42/42-70/70-98 =0.156, BMARunloaded days 14-42=1.7+/-0.1 microm/d, BMARunloaded days 42-70=1.8+/-0.2 microm/d, BMARunloaded days 70-98=1.6+/-0.4 microm/d, pBMARunloaded days 14-42/42-70/70-98=0.368, pBMARloaded/unloaded days 14-42=0.073, pBMARloaded/unloaded days 42-70=0.098, pBMARloaded/unloaded days 70-98=0.262). Four months after implant placement, the bone-to-implant contact was 77.8+/-17.3% for the loaded and 78.0+/-5.8% for the unloaded implants (P=0.753). Immediate loading does not affect the bone mineral apposition rate when compared with unloaded implants. Rigid splinting seems to be the crucial factor for implant success. Uncontrolled masticatory forces can cause failure after partial loss of the provisional restoration.

Three-year Prospective Evaluation of Immediately Loaded Mandibular Implant Overdentures retained with Locator Attachments

“…These factors include systemic condition of the patient, bone quality and quantity, cantilever forces, occlusal load direction, and position of implant. 26,27 Nkenke et al 28 found that immediate loading does not affect the bone mineral apposition rate when compared with unloaded implants if all conditions are under control. After 4 months of placement of implant, the bone-to-implant contact was 77.8% for the loaded and 78.0% for the unloaded implants.…”

3D Architecture of Trabecular Bone in the Pig Mandible and Femur: Inter-Trabecular Angle Distributions

“…The pigs were provided by Lahav C.R.O (Kibbutz Lahav, Israel). Pigs are considered to be a good nonhuman model for better understanding human skeletal and dental questions such as osteonecrosis of the femoral head, bone fractures, bone growth, and development, as well as for evaluating new dental implant designs (Buser et al, 1991;An and Freidman, 1998;Terheyden et al, 1999;Nkenke et al, 2003). While porcine bones in general have a denser trabecular network than human trabecular networks (Mosekilde et al, 1993), porcine bone shows similarities to human bone in terms of bone biology (modeling and remodeling), as well as bone mineral density (Mosekilde et al, 1993).…”

Two Bone Substitutes Analyzedin Vitroby Porcine and Human Adipose-Derived Stromal Cells

“…Moreover, the oral maxillo-facial region of these animals is similar to that of humans in anatomy, development, physiology, pathophysiology, and disease occurrence [22]. For this reasons, we and others consider these animals as a good preclinical model for bone disease and also for maxillofacial research; indeed, in the last years, they have been already used for pre-clinical study in dental implantology [16,23,24] and maxillo-facial surgery [25][26][27]. In this study, we analyzed two different bone substitutes: one is an implantable, reabsorbable, non-active, Class III medical device, specifically used as a scaffold for bone defect reconstruction.…”