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Bone Reaction (bone + reaction)
Selected AbstractsBone reactions to longstanding functional load at implants: an experimental study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2005T. Berglundh Abstract Objectives: The aims of the present investigation were (i) to study marginal bone level alterations following implant installation, abutment connection and functional loading and (ii) to analyse bone tissue reactions to functional load. Material and Methods: Six beagle dogs, about 1-year old, were used. All mandibular pre-molars were extracted. Three months later four implants of the Astra Tech Implants® Dental System were installed in one side of the mandible and four standard fixtures of the Brånemark System® were placed in the contralateral side of the mandible. Abutment connection was performed 3 months later and a plaque control programme was initiated. Three months after abutment connection fixed partial dentures (FPDs) made in gold were cemented to the maxillary canines and pre-molars. FPDs were also connected to the three posterior implants in each side of the mandible, while the mesial implant in each side was used as an unloaded control. Radiographs were obtained from all implant sites following implant installation, abutment connection and FPD placement. Ten months after the FPD placement the radiographic examination was repeated. The animals were sacrificed and biopsies from all implant sites were obtained and prepared for histological analysis. Results: The radiographic analysis revealed that largest amount of bone loss occurred following implant installation and abutment connection and that this loss was more pronounced at Brånemark than at Astra implants. The bone level alterations that were observed at implants exposed to 10 months of functional load in both implant systems were small and did not differ from control sites. The histological analysis revealed that implants exposed to functional load exhibited a higher degree of bone-to-implant contact than control implants in both implant systems. Conclusion: It is suggested that functional load at implants may enhance osseointegration and does not result in marginal bone loss. [source] Bone reactions to controlled loading of endosseous implants: a pilot studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 11 2008H. W. Anselm Wiskott Abstract Objectives: To validate an experimental setup designed to apply load onto bone tissue using osseointegrated implants in a rabbit model. Specifically, (1) to design an apparatus capable of generating controlled forces, (2) to assess implant placement, maintenance and loading and (3) to evaluate outcome variables using three radiological methods. Material and methods: New Zealand White rabbits were used. Two dental implants were inserted 15,18 mm apart in the animals' tibiae. After 3 months of healing, the implants were loaded normal to their long axes using a pneumatically activated device. A 15 min load regimen at 1 Hz was applied 5 days per week. Every week the applied load was increased by 5 N up to week 8 and by 10 N up to 100 N by week 14. Groups of animals (n=3) were sacrificed at load levels 25, 50 and 100 N. One unloaded controlateral implant in each group provided the baseline data. The rabbits were computer tomography (CT) scanned and radiographed using conventional frames every 4,5 weeks. After sacrifice, a volume of interest (VOI) located in the inter-implant zones and a VOI set as a ring surrounding the distal implant were analyzed using micro computer tomography (,CT). Results: A variety of osseous responses was observed, ranging from minor alterations to significant increases in porosity and lamelling of the cortical layer. ,CT data of the inter-implant VOI demonstrated an initial increase in total volume (upto 50 N) followed by stabilization. Concomitantly, bone volumetric density first decreased and then augmented until the end of the experiment. This phenomenon was not observed in the peri-implant VOI, for which volumetric density augmented from the beginning to the end of the experiment. Conclusions: 1. In future trials the loading devices must be constructed so as to sustain heavy cyclic loads over prolonged periods. 2. When properly handled, rabbits are cooperative animals in this application. In a third of the sites, signs of inflammation were observed. 3. In the inter-implant VOI, the cortical bone tended to react in two phases: first, as an increase in porosity and lamelling and second, as an augmentation of bone volumetric density. The peri-implant VOI adapted only by augmenting volumetric density. [source] Leprosy in a skeleton from the 7th century necropolis of Vicenne-Campochiaro (Molise, Italy)INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2005M. G. Belcastro Abstract Analysis of the skeleton from tomb 144 of the early medieval necropolis of Vicenne-Campochiaro in Central Italy revealed several features indicative of leprosy. The skeleton belongs to a male estimated to be between 20 and 25 years of age at death. The distal halves of the 1st and 2nd left metatarsals present acro-osteolysis and both legs show severe subperiosteal bone reaction. The facial skeleton shows changes compatible with a chronic inflammatory process, possibly due to an infectious disease. The anatomical distribution of the lesions and their association with other skeletal lesions seems to be compatible with a near-lepromatous form of leprosy. A differential diagnosis is made, and the skeletal traits pathognomonic of leprosy are discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Clinical Experiences of Computer Numeric Control-Milled Titanium Frameworks Supported by Implants in the Edentulous Jaw: A 5-Year Prospective StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2004Anders Örtorp DDS ABSTRACT Background: Few long-term follow-up studies on treatment concepts using computer numeric control-milled titanium frameworks have been conducted. Objective: To evaluate the clinical and radiographic performance of implant-supported prostheses provided with computer numeric control-milled titanium frameworks in the edentulous jaw and to compare their performance during the first 5 years of function with that of prostheses provided with conventional cast gold alloy frameworks. Materials and Methods: A consecutive group of 126 edentulous patients were randomly provided with 67 prostheses with titanium frameworks (test group) in 23 upper jaws and 44 lower jaws and with 62 conventional prostheses with gold alloy castings (control group) in 31 upper jaws and 31 lower jaws. Clinical and radiographic 5-year data were collected for the test and control groups. Results: The frequency of problems was low, and clinical and radiologic performances were similar in both groups. In the test group, the 5-year cumulative survival rates (CSRs) were 94.9% and 98.3% for implants and titanium prostheses, respectively. The respective corresponding CSRs for the control group were 97.9% and 98.2%. More loaded implants were lost in the maxillas in the test group (p < .01), but this difference was not significant on the patient/prosthesis level (p > .05). Smokers lost more implants than nonsmokers lost (p < .01). Similar survival rates were observed for implants in the mandible. One prosthesis was lost in each group because of the loss of implants. Metal fractures were seen only in the control group, and resin veneer fractures were more frequent in the maxilla in the gold alloy group (p < .05). In the test group, the mean marginal bone loss was 0.5 mm (SD, 0.44) in the maxilla and 0.4 mm (SD, 0.50) in the mandible. A similar pattern of bone reaction was observed in the control group. Mean marginal bone loss was similar for smokers and nonsmokers (p > .05). Conclusion: Computer numeric control-milled titanium frameworks are a viable alternative to gold alloy castings in the edentulous jaw and present clinical and radiologic performances similar to those of conventional gold alloy frameworks during the first 5 years of function. [source] Clinical Experiences of CNC-Milled Titanium Frameworks Supported by Implants in the Edentulous Jaw: 1-Year Prospective StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2000Anders Örtorp LDS ABSTRACT Background: A new type of titanium framework has been introduced, but so far no clinical reports have been made in this treatment modality. Purpose: The aim of this study was to report the clinical performance of implant-supported prostheses with computer numeric controlled (CNC)-milled titanium frameworks in the edentulous jaw and to compare the results with prostheses provided with conventional cast frameworks during the first year of function. Material and Methods: A consecutive group of 65 patients with 67 prostheses were provided with CNC-milled titanium frameworks in 23 upper and 44 lower jaws. During the same period, 61 consecutive patients were treated on a routine basis with 31 upper and 31 lower conventional gold alloy casting prostheses. Clinical and radiographic 1-year data were collected for both the test and control groups. Results: A total of 14 of 729 inserted implants were lost during the follow-up period (1.9%). All prostheses were functioning after 1 year except a conventional prosthesis with a cast framework, which was replaced by an implant-supported over-denture due to implant loss. The 1-year cumulative survival rate (CSR) was 100% and 97.8% for CNC prostheses and implants, respectively. The corresponding CSR for the control group was 98.3% and 98.3%, respectively. Few problems were reported in both groups, and the clinical and the radiologic performances were similar for both groups. No mechanical complications except some resin veneer fractures (n = 6) were observed. The mean marginal bone loss for the test group during the first year in function was 0.4 mm (SD = 0.35) and 0.4 mm (SD = 0.33) in the upper and lower jaws, respectively. A similar pattern of bone reaction was also observed in the control group. Conclusion: CNC-milled titanium frameworks can be used as an alternative to conventional castings in the edentulous jaw, presenting similar clinical and radiologic performances as conventional cast frameworks during the first year of function. [source] | ||||||||||