Statistical research needs in mechanistic modelling for carcinogenic risk assessment

This study reports the results of implant therapy involving a sinus membrane lift as well as conventional implant therapy in 24 periodontally compromised patients who were treated during the period between June 1990 and May 1995. Patients were included on the basis of being in need of at least 2 implants, 1 of which was to be placed in the maxillary sinus region, and at least 3 mm bone height was required in the sinus region. Following fenestration of the lateral sinus wall and lifting of the sinus membrane sinus implants were inserted as described for conventional implants. Annual follow-up visits included recording of plaque, probing pocket depth and bleeding on probing, and recording of the radiographic distance from the implant shoulder to the alveolar crest in mm. The Astra, Astra sinus, ITI, and ITI sinus were observed for an average of 30.8, 29.9, 29.4 and 25.3 months, respectively. Of the 80 implants inserted 1 Astra and 2 ITI had failed at 11-12 months and 1 ITI had failed at 42 months. The Kaplan-Meier estimate of the proportion of non-failed implants at 36 months were 100%, 95%, 91%, and 86% for the Astra, Astra sinus, ITI, and ITI sinus implants, respectively. Of the Astra, Astra sinus, and ITI implants, 71-82% remained free from bone-loss > or = 1.5 mm at 36 months, whereas this was the case for only 29% of the ITI sinus implants. About 80-90% of the implants remained free from plaque; 65-86% remained free from bleeding; and 44-80% remained free from pockets > or = 4 mm. These results indicate that the sinus lift technique can be used successfully in periodontally compromised patients.     

A comparative study of osseointegration of titanium implants in autogenous and freeze-dried bone grafts

PURPOSE: This study was undertaken to compare the rate and degree of osseointegration of dental implants when placed into either autogenous corticocancellous chip or freeze-dried corticocancellous chip bone grafts. MATERIALS AND METHODS: The canine ilium was used as the model site. Thirty experimental and 15 control implants were placed in 15 dogs: autogenous versus freeze-dried corticocancellous chip bone grafts around the exposed implant surfaces. In addition to the placement of control implants, the apical portion of the grafted implants acted as their own control. The implants were harvested at 1, 2, and 3 months. The evaluation of the integration process was performed by means of light microscopy, microradiography, and histomorphometry. RESULTS: Using this model, the results indicate that at 1 month there was no statistical difference in the degree of osseointegration in the two bone grafts. At 2 months, there was a statistically greater degree of osseointegration noted in the autogenous corticocancellous chip sites than in the freeze-dried bone grafts. At 3 months, the degree of osseointegration in the two groups was 70% and 33%, respectively. At 3 months, there was virtually 100% integration with trabecular bone at the control implant sites. CONCLUSION: The results indicate that at 2 months postoperatively implants placed in an autogenous bone chip graft osseointegrate to a significantly greater degree than implants placed in a freeze-dried bone chip graft, and this difference remains at 3 months.     

Rapid bone resorption adjacent to hydroxyapatite-coated implants

This paper describes rapid bone resorption in the peri-implantitis of HA implants based on both our clinical observations of and histological research on extracted dense hydroxyapatite (HA) implants. The surfaces of extracted HA implants were rough, although they were smooth at fixture placement. Plaque formed on the necks of the implants, whereas little plaque was seen on the bottoms. The plaque consisted of cocci and rods, including filamentous bacteria. Few spirochetes were observed. Although surrounding bone was formed rapidly around the HA implant, bone thickness gradually decreased compared with the titanium implant. These facts suggest that the rigid biointegration of HA with the thin surrounding bone--that is, the overstressing of the bone--causes rapid bone resorption rather than plaque accumulation on HA.     

Impairment, disability, and handicap in multiple sclerosis. A cross-sectional study in an incident cohort in M?re and Romsdal County, Norway

Non-submerged ITI Bonefit implants (ITI Dental Implant System) were inserted in edentulous lower jaws of 46 patients. The patients were provided with either a fixed prosthesis or an overdenture, and has been followed during a 2-year-period. At the 1-year examination, the suprastructures were removed permitting test of the individual implant stability. Radiographic examinations were performed in connection with the loading of the implants and at the 1-year examination. In total 216 implants were inserted. 4 implants were lost before loading and 4 during the 2nd year of function, which gives a survival rate after 1 year 98% and after 2 years of 96%. The mean marginal bone loss during the first year of function was 0.1 mm. However, the marginal bone changes had a high degree of variation and four implants showed a severe bone loss. The intention is to follow this patient group with annual examinations during 5 years.     

Mandibular onlay grafting using prefabricated bone grafts with primary implant placement: an experimental study in minipigs

The aim of this experimental study was to evaluate the use of prefabricated autogenous bone grafts as onlay grafts to the mandible. Excess bone of 10 x 12 x 40 mm was produced inside blocks of pyrolyzed bovine bone under a polylactic membrane coverage on the outside of the mandible in 15 adult G?ttingen minipigs. After 5 months, this bone was harvested and transferred to the premolar region of the mandibular body in 10 animals. Onlay grafts of mandibular bone were used as controls for the transplanted prefabricated grafts. All grafts were fixed by primary placement of one titanium implant each. Five animals served as ungrafted controls. Evaluation was performed after 3 months and 5 months, respectively. Two animals were lost to evaluation, and one scaffold became infected. Eleven of the remaining 12 scaffolds showed sufficient bone ingrowth for grafting. Three months after transplantation, bone volume of the prefabricated grafts was almost completely preserved, with only minimal resorption in the superficial pores of the scaffolds, while the control grafts exhibited partial resorption. The titanium implants, which had been placed at the time of only grafting, exhibited direct bone-implant contact. Five months after grafting, all titanium implants showed complete osseointegration, with direct bone-implant contact. The grafted bone exhibited a significant increase in bone density by appositional bone formation. The control grafts were nearly completely resorbed at that time.     

Histologic evaluation of the LaminOss osteocompressive dental screw: a pilot study

This animal study compared the response of canine mandibular bone using the orthopedic principle of osteocompression by the function of an immediately loaded dental implant vs an unloaded dental implant of the same design and size. Two dogs were partially edentulated in the mandible. A total of 8 osteocompressive screw implants, 2 per quadrant were placed and evaluated histomorphometrically after 3 days in 1 dog and after 3 months in the second dog. The second dog had a two-unit fixed bridge placed immediately postsurgically in occlusal function on the right side; on the left side, the implants were splinted out of occlusion as a control. Histologically, no bone necrosis was observed at the implant interface by any of the 8 implants for either period as a direct result of the 4-mm-diameter by 13-mm-length implant design. Clinical parameters did not differ among the implants; however, at 3 months, the immediately loaded implants demonstrated more than twice the amount of bone density at their surfaces compared to the unloaded implants of the same design. Future human clinical research would be necessary to provide a meaningful statistical analysis to validate the importance of this implant design and the function of osteocompression.     

Histologic analysis of clinically retrieved titanium microimplants placed in conjunction with maxillary sinus floor augmentation

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 Br?nemark 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.     

Magnetic resonance imaging lesion analysis in neurofibromatosis type 1

The purpose of this prospective study was to investigate the clinical outcome and marginal bone resorption of three different endosseous implants placed in the anterior mandibles of 15 elderly patients. Eleven women and 4 men (ranging from 65 to 80 years, mean 71 years) had three different endosseous implants placed in the anterior mandible; one titanium plasma-sprayed cylinder implant (4-mm diameter), one titanium cylinder implant with hydroxyapatite coating (4-mm diameter), and one standard threaded titanium implant (3.75-mm diameter). Three months later, at the second-stage surgical procedure, ball abutments were connected and an overdenture was placed. At 12, 24, and 36 months, marginal bone resorption and Periotest values were recorded. None of the implants was lost in this period. An analysis of variance with repeated measurement was performed annually to test the existence of significant differences between the implants. When differences appeared, paired t tests were used to identify which differences were significant. Bonferroni multipliers were used to adjust for multiple testing. When marginal bone resorption was concerned, threaded titanium and hydroxyapatite-coated implants had significantly better scores than titanium plasma-sprayed cylinder implants. Periotest values for hydroxyapatite-coated implants were significantly better than test values for the other implants after 2 years. After 3 years significance was obtained between hydroxyapatite and screw-shaped implants only (P < .05). It was concluded that titanium plasma-sprayed cylinder implants have a less favorable prognosis than the other implants used in this study.     

The relationship between myenteric neuronal denervation, smooth muscle thickening and epithelial cell proliferation in the rat colon

The aim of the present experiment was to (i) study the healing after 3 and 7 months of bone defects filled with cancellous bovine bone mineral and (ii) compare the healing around implants placed in normal bone and in defects filled with bovine bone mineral. 5 beagle dogs, about 1-year-old, were used. At baseline, extractions of all mandibular left and right premolars were performed. Bone defects were prepared in the left mandibular quadrant. The defect was immediately filled with natural bovine cancellous bone mineral particles (Bio-Oss, Geistlich Sons Ltd. Wolhusen, Switzerland). No resective surgery was performed in the right jaw quadrant. In both quadrants the flaps were adjusted to allow full coverage of the edentulous ridge and sutured. 3 months later, 2 dogs (group I) were euthanized and biopsies from the premolar regions obtained and prepared for histologic analysis. The 3 remaining dogs (group II) were at this time interval (3 months) subjected to implant installation in the premolar region of both the right and left mandibular jaw quadrants. 2 fixtures of the ITI Dental Implant System (Straumann, Waldenburg, Switzerland; solid-screw; 8 x 3.3 mm) were installed in each side. The fixtures in the test side were placed within the previously grafted defect area, while the fixtures in the control side were placed in normally healed extraction sites. A 4 month period of plaque control was initiated. At the end of this period, a clinical examination including assessment of plaque and soft tissue inflammation was performed and radiographs obtained from the implant sites. Biopsies were harvested and 4 tissue samples were yielded per dog, each including the implant and the surrounding soft and hard peri-implant tissues. The biopsies were processed for ground sectioning or "fracture technique" and the sections produced were subjected to histological examination. The volume of the hard tissue that was occupied by clearly identified Bio-Oss particles was reduced between the 3- and 7-month intervals. This indicates that with time, Bio-Oss becomes integrated and subsequently replaced by newly formed bone. In other words, this xenograft fulfils the criteria of an osteoconductive material. It was also observed that 4 months after implant installation, the titanium/hard tissue interface at test and control sites exhibited, from both a quantitative and qualitative aspect, a similar degree of "osseointegration".     

HLA-A towards a high-resolution DNA typing

PURPOSE: This study assessed the soft tissue changes produced by the placement of hard tissue replacement (HTR) polymer chin implants for augmentation genioplasty and evaluated the dimensional stability as well as any bony changes associated with the implants. PATIENTS AND METHODS: The study group consisted of 18 patients (3 males, 15 females) with an average follow-up of 21.5 months (range, 12 to 44 months). All implants were placed through an intraoral incision and stabilized to the symphysis with a single 2.0-mm diameter titanium screw. Preoperative, postoperative, and long-term cephalometric radiographs were analyzed for changes in soft tissue thickness in the chin region, implant stability, and the presence of bone resorption. RESULTS: The net hard tissue chin augmentation achieved averaged 6.0 mm (range, 4.5 to 9 mm). Average preoperative soft tissue thickness was 12.1 mm (range, 11 to 14.5 mm) and postoperatively it was 10.6 mm (range, 10 to 13.5 mm). The average increase in soft tissue projection was 77.6% (range, 71.4% to 83.3%) of the implant thickness. There was no radiographic evidence of implant migration or bony resorption beneath the implant. CONCLUSIONS: HTR implants appear to be a predictable means of augmenting the chin, providing the desired aesthetic change, without causing resorption of underlying bone.     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Part I. Evaluation of anorganic bovine-derived bone matrix

The aim of this study was to evaluate clinically, histologically and histometrically the use of anorganic bovine bone matrix (i.e. Bio-oss) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Macaca mulatta) the 1st, 2nd and 3rd maxillary molars on one side of the jaws were extracted. The remaining bone between the alveolar crest and the bottom of the sinus was then reduced to 3-4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey and the sinuses were grafted with the bovine bone matrix. At that time, 2 IMZ pure titanium plasma coated implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into these previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants-unloaded group and delayed implants-unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited significant bone formation with integration of the bovine bone matrix particles to the new bone. Direct mineralized bone-to-implant contact was greater for the delayed implant placement groups than for the implants installed simultaneously with the sinus augmentation. Furthermore, the percentage of direct mineralized bone-to-implant contact was greater in the residual bone than in the augmented area. It was concluded that the anorganic bovine bone matrix facilitated bone formation and implant osseointegration in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure seemed to be preferable.     

Bone ingrowth to implant surfaces in an inflammatory arthritis model

Many studies have shown enhanced bone apposition to implants coated with hydroxyapatite, but the optimum implant texture, especially in abnormal trabecular bone, is unclear. The purpose of this project was to evaluate the histological and mechanical properties of cylindrical implants with three different surface textures that were placed in the cancellous bone of the distal femur of the rabbit after the production of an inflammatory knee arthritis. The three implant surfaces included a beaded surface (Group A), a beaded surface coated with hydroxyapatite (Group B), and a smooth surface coated with hydroxyapatite (Group C). The right knees of 36 rabbits were injected with carrageenan twice a week for 2 weeks. Then bilateral implantations were performed, with 12 rabbits in each group receiving identical implants in the right and left knees. The rabbits were killed 6 weeks after surgery. Mechanical (push-out test) and histomorphometric analyses were performed to determine the quality and quantity of bone ingrowth. In Group A, there was virtually no direct contact (a 20-60-microm clearance) between the bone and the beaded surfaces. Direct contact between the bone and the implant surfaces was seen in Groups B and C. The thickness and number of trabeculae were smaller on the arthritic side than on the control side for all groups but were not different between groups for either the control or the arthritic side. Mechanical testing showed that the shear strength of the interface was weaker on the arthritic side in all groups. The results suggest that inflammatory arthritis induced by carrageenan may influence the quality of local bone (osteopenic changes) and hence compromise the bone apposition and mechanical stability of the interface between the implant and bone.     

The use of osteotomes for sinus augmentation at the time of implant placement

The placement of endosseous dental implants is often hampered by the loss of alveolar bone. In the posterior maxilla, the presence of the maxillary sinus and less-dense bone present additional obstacles to successful implant placement. Existing methods of subantral augmentation require extensive surgical manipulation, often including a second surgical site for harvesting autogenous bone. The development of surgical osteotomes has facilitated the placement of implants in areas of minimal alveolar bone height in the posterior maxilla. This article describes the osteotome technique for sinus augmentation at the time of implant placement and presents a short-term evaluation of 34 implants placed in 18 patients.     

Biomechanical and histologic alteration of facial recipient bone after reconstruction with autogenous bone grafts and alloplastic implants: a 1-year study

Potential alteration of the underlying recipient bone resulting from a graft or implant has significant clinical relevance. The present study was designed to evaluate the biomechanical and histologic alteration of facial recipient bone with autogenous bone graft and alloplastic implants over a 1-year period. The bilateral arches of 15 rabbits were randomized between four groups: (1) control (n = 6), subperiosteal exposure of the zygomatic arch was made; (2) onlay (n = 12), bone graft was placed as an onlay to the zygomatic arch; (3) inlay (n = 6), bone graft was placed as an inlay within the zygomatic arch; (4) implant (n = 6), a stainless steel plate was placed as an onlay to the zygomatic arch. Animals were killed 1 year after grafting. In the onlay groups, all steel implants and half of the onlay bone grafts (n = 6) were separated from the zygomatic arch; the remaining onlay bone grafts (n = 6) were left on the zygomatic arch. Three-point breaking strength was measured through the center of the graft/implant site on the zygomatic arch, followed by histologic evaluation and histometric assessment of residual bone density. The findings demonstrated no difference in the breaking strength per unit bone area between the control zygomatic arch group and the onlay group in which the bone graft was left in place. Breaking strength of the zygomatic arch in the former two groups was significantly greater than that in either group in which the onlay bone graft or implant had been removed, and was also greater than the breaking strength in that group in which inlay bone had been placed (p < 0.05). Histologic assessment showed full-thickness conversion in architecture of the zygomatic arch from compact to woven bone beneath onlays of either autogenous bone graft or steel implant; histometric assessment demonstrated an accompanying decrease in bone density in the latter groups relative to the control zygoma (p < 0.05). We conclude that onlay autogenous bone graft and alloplastic implants to the facial skeleton induce transformation of both graft and recipient bone from compact to woven architecture, accompanied by a reduction in bone density. The biomechanical strength of recipient facial bone is significantly weakened if an onlay bone graft or implant is removed. Weakening occurs per unit area of remaining bone, and is therefore independent of any thinning that may occur within the recipient bone because of graft/implant placement. These findings may impact upon decisions to augment stress-bearing regions of the facial skeleton with bone graft or implants, particularly if the graft/implant may eventually require removal.     

Isolation and characterization of wheat aluminum-regulated genes: possible involvement of aluminum as a pathogenesis response elicitor

This retrospective study involved Japanese patients with prostheses supported by Br?nemark implants following maxillectomy. Questionnaires were sent to 75 institutions, and data on 19 patients were collected from 8 institutions. The mean age of patients at the time of implant placement was 64.2 years (range 22 to 82 years). The mean follow-up time was 27.6 months. Of the 81 implants placed, 16 were lost for an implant survival rate of 80.2%. The effects on implant survival rate of radiotherapy, chemotherapy, hyperbaric oxygen therapy, and the support system of the prosthesis were analyzed, but no significant differences were observed.     

Superficial hemangiomas: associations and management

A new design of single tooth implant (AstraTech, Molndal Sweden) featuring a microthreaded conical neck and TiO blast surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4, 13 mm and 11, 15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance. Radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year (14 subjects) and 2 years (12 subjects). All implants were successfully integrated at stage 2, and no implants have been lost. The internal conical seal design of the abutment/implant interface facilitated connection and there were no cases of abutment screw loosening. No soft tissue problems were observed, and the gingival morphology/health was well maintained. One crown was recemented after 18 months in function, and 1 crown was replaced because of a fracture to the porcelain incisal edge. At crown insertion, the mean bone level was 0.46 to 0.48 mm apical to the top of the implant and there were no statistically significant changes in the bone level over the 2 years of the study. In conclusion, the single tooth Astra implants were highly successful and bone changes within the first 2 years of function were comparable with other systems reporting high long-term success rates.     

Guided bone regeneration around dental implants in the atrophic alveolar ridge using a bioresorbable barrier. An experimental study in the monkey

The aim of this study was to evaluate guided bone regeneration (GBR) around dental implants placed in atrophic alveolar ridges using an experimental, nonporous bioresorbable barrier. In 8 Rhesus monkeys, the maxillary canines and lateral incisors were extracted bilaterally and the remaining alveoli were reduced to create atrophic ridges. After a healing period of 3 months, soft tissue expansion was performed using a subperiosteal tissue expander. After 1 month of tissue expansion, and IMZ implant was placed in the atrophic ridge on each side in such a way that its coronal 4 mm to 5 mm remained circumferentially exposed above the bone level. The test implants were covered with a bioresorbable barrier made of poly (D,L-lactid-co-trimethylencarbonate) in a 70/30 ratio, whereas the control implants were covered with a nonresorbable expanded polytetrafluoroethylene (e-PTFE) barrier. The e-PTFE barriers were stabilized with titanium minipins while the bioresorbable barriers were analogously fixed using bioresorbable minipins made of poly (L-lactid-co-D,L-lactid) 70/30. Clinical healing progressed uneventfully in both groups and no soft tissue dehiscences occurred. Histometric and histomorphometric analyses were performed 5 months post surgery. Both test and control implants exhibited direct bone-to-implant contact to variable extents. The mean direct mineralized bone-to-implant contact length fraction was 32% of the total implant length in the test sites and 58% in the control sites. Control sites exhibited significantly greater bone fill compared to the experimental sites (P < 0.001). Histologic observations of test specimens demonstrated a moderate inflammatory reaction related to the degradation and resorption products of the barrier. In conclusion, the nonresorbable e-PTFE GBR barrier was found to be superior to the bioresorbable barriers tested in the present investigation.     

Short (6-mm) nonsubmerged dental implants: results of a Multicenter clinical trial of 1 to 7 years

Limited bone height restricts the use of long dental implants, so short implants may be selected in these situations. Recent reports on clinical results with short implants have been negative, however, and have suggested that indications for the use of these implants are limited. To verify these findings, a multicenter study of short ITI implants was carried out. In a 6-year period 253 short implants with a length of 6 mm were placed into 126 patients, who were followed up from 1 to 7 years. Altogether 7 implants were removed; 6 of these were located in the maxilla and 1 in the mandible. The quality of survival was comparable with the clinical results of longer implants from the same implant system. Although the clinical results of these short implants were favorable, it is recommended that they be used in combination with longer implants, especially when used in the less dense bone that is often seen in the maxilla.     

Implant reconstruction of the jaws and craniofacial skeleton

Full oral rehabilitation with a high degree of success is now possible with osseointegrated implants. Osseointegration is a direct connection between living bone and the titanium implant at the level of the light microscope. Osseointegrated implants are currently used to replace single teeth, support fixed bridges and stabilize full dentures. These implants can also be placed extraorally for attachment of facial prosthesis. The surgical technique used to place implants intraorally into jaws or facial skeleton is performed in two stages using a local anesthetic and/or conscious sedation. During stage I surgery, holes are placed into the jaw using a series of gradually larger diameter burs until the desired diameter and depth of the bony preparation is achieved. The implant is then placed. The implant must remain undisturbed for 4 months for osseointegration to take place. Stage II surgery is then required to remove the mucosa over the implant and place the transmucosal abutment. After 1-2 weeks of healing, the restorative dentist can take an impression and fabricate the prosthesis. On occasion, it is necessary to augment the height and width of the atrophic jaw with autogenous or allogeneic bone grafts prior to implant placement. Bone grafts are sometimes placed on the floor of the nose or the floor of the maxillary sinus. Guided tissue regeneration is a technique used to generate bone within bony defects adjacent to implants. With long-term rates of success (5 years) of 99% for implants placed in the mandible and 95% for those placed in the maxilla, reconstruction of the jaws and cranial facial skeleton with osseointegrated implants has become the treatment of choice.     

Cemented femoral component surface finish mechanics

A cemented femoral component's surface finish may influence implant function through variations in cement adhesion and abrasion properties. Morphologic characterization of historic and current femoral hip prosthesis surface finishes show greater than x 20 range in implant roughness. Early implants typically had relatively smooth surfaces, whereas many of the more recent implants have rougher surface finishes. Smoother implant surfaces have lower cement-metal interface fixation strength, whereas rougher surfaces have greater fixation strength. With interface motion, the smoother surfaces are less abrasive of bone cement, whereas rougher implant surfaces are more abrasive. Because of enhanced bone cement attachment, rougher implant surfaces may have a lower probability of interface motion, while at the same time, a higher debris generation consequence if motion occurs. In contrast, smoother implant surfaces may have a higher probability of interface motion with a lower debris generating consequence of that motion. The prolonged use of cemented total hip replacement may be approached by either extending the duration of implant function after cement-metal interface loosening with smooth surfaced implants or, in contrast, by extending the duration of cement-metal interface adhesion with rougher surfaced implants.