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The present study aimed to evaluate the osseoconduction ability of an airborne particle--abraded and etched (SAE) titanium alloy surface when placed in humans with poor bone quality. Four patients scheduled to receive an implant-supported full-arch prosthesis received two additional reduced-diameter implants to be harvested after 6 months of submerged healing. Undecalcified vestibulopalatal/ vestibulolingual histologic sections were prepared after the micro-computerized tomography (µCT) examination. Six implant sides from four biopsied implants displayed a type IV bone environment and were included in the present study. Bone-to-implant contact (BIC) was first measured on each implant side. The estimated initial BIC (E-iBIC) was evaluated by superimposing the implant profile 0.25 mm away from its actual position. The µCT provided information about the local and adjacent bony architecture. The mean BIC was 62.5% ± 10.6%, while the mean E-iBIC was 33.1% ± 4.4%. The E-iBIC/BIC ratio was 1.81 ± 0.38. The 3D µCT sections showed the thin bone trabeculae covering the implant surface; although they seemed to be separated from the rest of the bony scaffold, they were much more interconnected than what appeared to be on the 2D histologic preparations. This limited number of human histologic samples document, for the first time, that the SAE titanium alloy implant surface is apparently osseoconductive when placed in poor human bone quality. The average BIC was 1.81 times higher than the E-iBIC. This high osseoconductivity may explain the predictable clinical behavior of implants with this type of SAE textured surface in type IV bone. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effect of controlled progressive orthodontic loading on bone around implants subjected to overloading forces. Materials and Methods: Bilateral edentulous alveolar ridges were created in the posterior maxilla of five beagle dogs and left to heal for an 8-week period, after which 40 implants were placed. In the overloading group (OL), 16 implants were inserted and left to osseointegrate for 16 weeks; impressions were made, and metal crowns were mounted on with supraocclusal contacts with the antagonist teeth. Implants were exposed to dynamic overloading for 16 weeks. In the progressive loading + overloading group (PL+OL), 16 implants were left to osseointegrate for 8 weeks, and custom abutment cores were fabricated and coupled by pairs with Ni-Ti orthodontic springs. Ascending static forces of 100g, 200g, and 300g were each applied for a 3-week period, for a total 9-week progressive loading period. Thereafter, metal crowns with supraocclusal contacts were adapted, and a 16-week overloading protocol for implants was followed as for the overloading group. In the unloaded control group (UL), eight implants were inserted and left uncovered and unloaded for 32 weeks, that is, until the end of the experimental period, at which point all 40 implants were removed with the surrounding bone. Histologic, histomorphometric, and statistical analysis followed. Results: Higher bone-to-implant contact percentage was reported for the OL group (P = .006) and PL+OL group (P < .001) compared with the UL group. Between the OL and PL+OL groups, the addition of progressive loading did not increase the bone-to-implant contact percentage (P = .225). Bone density 1 mm and 2 mm distant to the threads did not differ significantly between the three groups. Significantly lower crestal bone resorption was detected around OL group implants (P = .006) and PL+OL group implants (P = .004) compared with the UL group implants. The implant success rate was 87.5% for the UL group, 67.5% for the OL group, and 87.5% for the PL+OL group. Conclusion: The application of controlled progressive orthodontic loading on osseointegrated implants preceding overloading forces did not increase bone-to-implant contact. When applied, overloading significantly increased bone-to-implant contact compared with the unloaded implants. A significantly higher implant success rate was reported in the PL+OL group compared with the OL group. [ABSTRACT FROM AUTHOR]

This report presents six consecutive cases of peri-implantitis associated with residual methacrylate cement. The cases responded to cement removal and disinfection procedures. Six patients, each presenting one methacrylate cementretained implant restoration and showing peri-implant inflammation and bone loss, were treated. All the cases were negative for bleeding on probing after 6 weeks, and this was maintained at 1 year of follow-up from nonsurgical therapy and crown refixation with alternative and resorbable cement. The treatment effectively solved the inflammation and led to complete restoration ad integrum, as evaluated clinically and radiographically, after 1 year. [ABSTRACT FROM AUTHOR]

Purpose: Primary implant stability represents the first step for successful osseointegration. The knowledge of the correlation between host bone density, insertion torque, and implant macrogeometry seems to be fundamental to achieve sufficient primary implant bone fixation in each clinical situation. The purpose of this study was to measure, in vitro, the impact of dental implant macrogeometry and insertion torque values on primary stability in relation to different bone densities, representing both the human mandible and maxilla. Materials and Methods: One hundred twenty 3.8 × 11-mm commercial dental implants were used. Forty implants had small threads with a machined neck, 40 implants had small threads with a microthreaded neck, and the last 40 implants had large threads with a reverse neck design. Fresh bovine ribs, representing a medium-dense bone density (D2-D3), and fresh ovine iliac crest, representing a soft bone density (D4), were used. Insertion torque and micromobility under lateral force data were recorded for each implant. Results: In the medium-dense bone type, the reverse neck implant design showed less primary implant stability than the conventional straight implant neck. In soft bone, both implants with the large thread design and microthreaded neck implants showed better implant stability than the implant with a small thread design with a straight machined neck. Implants with large and self-cutting threads showed significantly (P < .05) lower micromobility values than other implants in postextractive sites in low-density bone. Conclusion: Implant geometries and bone density are the main factors involved in the degree of primary implant stability. Large-thread implant designs are highly desirable in cases of poor bone quality. Each implant geometry generates an insertion torque value, which is correlated to the stability of that specific implant in a specific bone quality, but the insertion torque is not an objective value to compare primary stability between different implant types. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare microcomputed tomography (microCT) and histologic analysis outcomes of a periodontal regeneration of a human defect treated with a polylactic- and polyglycolic-acid copolymer. At 11 months following the grafting procedure, the root with the surrounding periodontal tissues was removed and analyzed using microCT and histologic techniques. The results suggest that microCT three-dimensional analysis may be used in synergy with two-dimensional histologic sections to provide additional information for studying the regeneration outcomes normally reported by histologic biopsies in humans. Additional data is needed to validate these findings. [ABSTRACT FROM AUTHOR]

The purpose of this study was a histomorphometric comparison of vital bone formation following maxillary sinus augmentation with two different particle sizes of anorganic bovine bone matrix (ABBM). Bilateral sinus floor augmentations were performed in 13 patients. Trephine bone cores were taken from the lateral window areas of 11 patients 6 to 8 months after augmentation for histologic and histomorphometric analysis. Bone samples from both the large and small particle size groups showed evidence of vital bone formation similar to that seen in previous studies, confirming the osteoconductivity of ABBM. Significant bone bridging was seen creating new trabeculae composed of the newly formed bone and residual ABBM particles. Histologic evaluation revealed the newly formed bone to be mostly woven bone with some remodeling to lamellar bone. Osteocytes were seen within the newly formed bone as well as osteoblast seams with recently formed osteoid. Isolated osteoclasts were observed on the ABBM surfaces. Vital bone formation (primary outcome measure) was more extensive in the large particle grafts compared with the small particle grafts (26.77% ± 9.63% vs 18.77% ± 4.74%, respectively). The histologic results reaffirm the osteoconductive ability of ABBM when used as the sole grafting material in maxillary sinus augmentation. The histomorphometric results at 6 to 8 months revealed a statistically significant increase (P = .02) in vital bone formation when the larger particle size was used. Additional studies should be performed to confirm these results. [ABSTRACT FROM AUTHOR]

Immediate loading of dental implants can significantly decrease treatment time and thus increase patient acceptance. However, there is still a need to investigate whether an implant in which primary stability is achieved can be immediately loaded without the formation of connective fibrous tissue at the interface. Three transitional implants were placed in an edentulous mandible: two implants loaded immediately and one left unloaded. All transitional implants were retrieved after a period of 12 weeks to perform qualitative and quantitative analysis of the peri-implant tissue and bone-implant interface. Bone biopsy specimens containing the transitional implant were analyzed using microcomputed tomography (micro-CT). Subsequently, the same samples were analyzed using standard undecalcified histology. Micro-CT analysis showed that bone tissue was slightly detached from the surface of the loaded implant. Histology demonstrated the presence of a soft tissue layer inside the socket. Morphometric values of total bone volume, bone-implant contact, and bone connectivity were higher for the unloaded implant, which appeared to be covered by an almost continuous layer of bone. Micro-CT evaluation of some morphometric parameters and histologic results pertaining to small-diameter transitional implants showed that uncontrolled loading may produce untoward effects on peri-implant bone healing. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to analyze, in an animal model, the histologic and biomechanical phenomena at the bone-implant interface of implants inserted with high torque (HT) as compared to low torque (LT) during the first 6 weeks of healing. Materials and Methods: Forty tapered-screw-form implants were placed in five hybrid sheep. The implant sites were placed in the mandible, using an extraoral approach; four were placed with HT (test: mean 110 Ncm) on one side and four were placed with LT (control: mean 10 Ncm) on the contralateral side. After 1, 2, 3, 4, and 6 weeks of healing, removal torque testing and resonance frequency analysis were performed and the animals were sacrificed for histologic examination. Results: Implants from the HT group showed significantly higher bone apposition than implants from the LT group at all examined healing times. Similarly, removal torque was consistently higher for the HT as compared to the LT group. A significant loss of primary stability in the HT group was evident 7 days after placement. Implants from the LT group achieved a significant increase in stability after 4 weeks. Resonance frequency analysis was unable to detect these histologic and biomechanical modifications of the bone-implant complex. Conclusions: The results of the study showed that high implant insertion torque in dense cortical bone does not induce bone necrosis or implant failure, but it does increase the primary stability of implants, which is extremely important in immediate loading protocols. [ABSTRACT FROM AUTHOR]

Purpose: To obtain more objective presurgical measurements of clinical interest, this study proposes a new method of measuring and classifying bone density. Materials and Methods: The density of bovine bone blocks of different qualities was first measured in Hounsfield units (HU) using computed tomography (CT). Next, bone cylinders corresponding to each examined area were retrieved. Bone quality was then measured by both histomorphometric microCT and by subjective evaluation of bone quality during drilling. Results: A statistically significant correlation was found between CT and microCT measurements. Based on this evidence, a new method of classifying bone density/quality into three classes of clinical interest was developed: hard/dense, normal, and soft (HNS). These statistical data also enabled the creation of a formula to convert ordinary CT values expressed in HU into bone volume percentages (BV%) to objectively measure bone density based on the HNS system. Conclusion: Stable implant placement depends upon measurements of bone quality/density that are site-specific, objective, and quantitative. To meet these standards, this paper reports an innovative method of classifying bone quality/density and then objectively measuring bone density based on this HNS classification system, using a simple, innovative mathematical formula that converts HU values into measurements of bone volume. [ABSTRACT FROM AUTHOR]

Bisphosphonates are pharmacologic compounds characterized by high tropism to bone tissue. They affect bone metabolism by inhibition of osteoclast recruitment, proliferation, differentiation, and function. Because they can reduce bone resorption, bisphosphonates are used mainly for the treatment of osteometabolic conditions, particularly osteoporosis, Paget disease, multiple myeloma, and other solid tumors with bone metastases. Their use has conferred great benefits to patients affected by these diseases, significantly improving their quality of life. Bisphosponates' inhibition of bone resorption might be exploited to maintain implant primary stability during the process of implant osseointegration. The aim of this histologic clinical study was to compare the response of bone tissue around an implant treated with a bisphosphonate solution (test) to that of the bone around an untreated implant (control). The bisphosphonate-treated implant showed more contact with newly formed bone than the control implant. [ABSTRACT FROM AUTHOR]

The most frequent intraoperative complication with sinus elevation is perforation of the schneiderian membrane. In most instances, the repair of this perforation is necessary to contain particulate grafting material and complete the procedure. New techniques are presented here for the management of large perforations of the schneiderian membrane. A bioabsorbable collagen membrane is stabilized outside the antrostomy and then folded inward to create either a new superior wall that can obliterate a large perforation or a "pouch" that can completely contain the particulate material. This can make it possible to complete a procedure that otherwise may have had to be aborted by preventing dispersion of the particulate graft within the sinus cavity. Clinical cases are shown, along with follow-up at 6 to 9 months, demonstrating histologic and/or radiographic evidence of success, continued sinus health, and superior vital bone formation. The authors have used this technique on 20 consecutive patients without experiencing any procedural failures. [ABSTRACT FROM AUTHOR]

Autogenous grafting of gingival or bone tissue is often indicated to obtain optimal esthetics and function in periodontal and implant therapy. In the present study, 32 maxillary teeth were extracted, and the postextraction defects were treated with 32 autogenous cylindric free gingival-bone grafts retrieved with trephine burs from intraoral donor sites. Free gingival-bone grafts were also used to obtain root coverage and papilla reconstruction in three patients who required esthetic enhancement. Twelve to 16 weeks after the graft procedure, biopsies were retrieved and processed for histologic evaluation to verify integration of the grafts. The implants placed in the treated sites healed without complications and were functionally loaded after healing. The clinical and histologic results of this study suggest that the free gingival-bone graft technique may favor hard and soft tissue reconstruction of the sites treated, with esthetic and functional advantages. [ABSTRACT FROM AUTHOR]

In this prospective randomized controlled clinical study, small titanium implants were placed in posterior maxillae for the purpose of assessing the rate and extent of new bone development. Nine pairs of site evaluation implants were placed in posterior areas of maxillae and retrieved with trephine drills after 4 or 8 weeks of unloaded healing. The amount of bone in linear contact (%) with the implant surface was used to determine the osteoconductive potential of the implant surface. Implant surfaces were dual acid etched (n = 9) (controls) or dual acid etched and further conditioned with nanometer-scale crystals of calcium phosphate (n = 9) (test implants), and the surfaces were compared. The implants and surrounding tissues were processed for histologic analysis. The mean bone-to-implant contact value for the test surface was significantly increased over that of the control implants at both time intervals (P < .01). For the implants/patients included in this study, the addition of a nanometer-scale calcium phosphate treatment to a dual acid--etched implant surface appeared to increase the extent of bone development after 4 and 8 weeks of healing. [ABSTRACT FROM AUTHOR]

The aim of this case report was to evaluate the ability of Bio-Oss used together with an expanded polytetrafluoroethylene, titanium-reinforced membrane to restore a vertical bone defect. Bio-Oss served as a filler material. After the membrane was removed, screw-type implants were placed. During this phase, cylindric bone samples were retrieved from the augmented area for histologic examination. The biopsy samples were composed of low-density trabecular bone with numerous interspersed graft particles. Clinical and histologic results demonstrated that this surgical technique could be a successful and predictable procedure for rebuilding a resorbed ridge to place implants. [ABSTRACT FROM AUTHOR]

Three sinuses were grafted with a bioactive glass bone substitute (Biogran) mixed with autogenous bone retrieved from intraoral donor sites. In two of the three sinuses a platelet-rich plasma (PRP) gel was added to the graft. Bone biopsies retrieved after 5, 6, and 15 months were analyzed. Micro-computerized tomography (micro-CT) values of total bone volume/total volume (TBV/TV) were very reliable compared to histomorphometry. Biogran mixed with autogenous bone and PRP seems to have a positive effect in sinus grafting, with TBV/TV values ranging between 40% and 68%. Micro-CT results have never been compared with histomorphometry for the evaluation of grafted biomaterials. Micro-CT evaluation of some morphometric parameters was difficult, because the radiodensities of Biogran and a certain grade of bone mineralization were similar. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate how closely analysis of bone quality performed using the bone mineral density (BMD) values obtained by quantitative computerized tomography (QCT) reflected the histologic bone density. Materials and Methods: Eighteen patients requiring implant therapy underwent CT scanning. Their data were processed using Image Master software, and the BMD was calculated by measuring the Hounsfield units and relating those values to a phantom (Calibration Phantom, Quantitative Technologies). Each patient wore a radiographic-surgical template in which titanium cylinders were placed as a drilling guide for preparation of the implant site. The mouth regions where the titanium guides were placed (on the CT images and in the patient's mouth) corresponded to the implant sites where the BMD was measured and where tissue specimens for histomorphometric analysis retrieved. Forty specimens measuring 6 mm in length and 2 mm in diameter were obtained. Histomorphometric analysis was performed by digitizing the images, which were subsequently analyzed using the image analysis software IAS 2000. The bone volume (BV) was calculated as a percentage by dividing the area occupied by the mineralized bone over the entire microscopic field. Results: The results of the statistical analysis showed a Pearson correlation coefficient of 0.691 between the BV and BMD values, with a P value < 0.01, which was considered significant. Discussion and Conclusion: The results of this study support the use of QCT to assess the bone quality before implant placement to improve the planning of implant treatment. [ABSTRACT FROM AUTHOR]

Seventeen endosseous titanium implants were placed in completely edentulous jaws of 15 patients. The implants were loaded immediately or after 2 or 6 months, with 100 g orthodontic force. Three weeks later, the implants were removed and histologically analyzed. All of the immediately loaded implants, along with three of the eight that were loaded after 2 months, were lost. The remaining implants were stable until the end of the study. Histologic analysis of the retrieved implants showed bone remodeling in the cortical bone, thickening of the bony trabeculae by new lamellar bone deposition, and microcalli of woven bone or a lattice of woven bone formation around some implants that had been placed in soft bone. Tetracycline labeling revealed an elevated amount of newly formed bone. If further studies prove that a controlled application of orthodontic force, before application of occlusal loading, is able to rapidly enhance the density of soft peri-implant bone, we will have a powerful and precise tool to improve the rate of implant success. [ABSTRACT FROM AUTHOR]

Purpose: No consensus exists on the long-term performance of hydroxyapatite (HA) coatings on dental implants. The aim of this study was to evaluate the long-term stability of the HA coating in a human autopsy specimen. Materials and Methods: Two mandibular HA-coated implants were retrieved post-mortem from a woman after 10 years of functional loading with an implant/tooth-supported fixed partial denture. After ground sectioning, the specimens were histomorphometrically analyzed. Results: Direct bone-implant contact was found at 78.48% of the implant surface. HA coating disappearance had occurred in a few areas (22.75%), but bone was in direct apposition to the titanium surface. Bone volume measured 27.66%, and expected bone-implant contact was 37.55%. No inflammatory reaction was seen in the supracrestal soft tissues or the bone compartment. Discussion: Most of the HA coating was maintained on the implants, and areas lacking HA were directly apposed by bone. This observation suggests that the underlying titanium surface should have a macro-texture to promote the adaptation of bone to the titanium surface in case of HA disappearance, as well as to decrease failure at the HA-titanium interface. Conclusions: In a patient in whom prosthetic treatment was appropriately performed and proper plaque control was maintained, the HA coating was not damaged and contributed to the success of the implant over 10 years of clinical functioning. [ABSTRACT FROM AUTHOR]

A recently developed technology allows evaluation of bone biopsies with 3-D microcomputed tomography (microCT). The present study evaluated the feasibility of application of microCT to the analysis of peri-implant bone tissues. A human bone biopsy containing a titanium screw was analyzed using a microCT scan. The parameters computed by the microCT were bone volume, bone surface, trabecular thickness, trabecular separation, and bone connectivity. Also, the bone-to-implant apposition was measured, and all results were compared with those obtained with standard histomorphometry of the same biopsy. The results of the present study suggest that microCT enables 3-D nondestructive evaluation of bone biopsies containing endosseous titanium implants, also allowing analysis of the bone-implant interface. Measurements of bone-to-implant apposition obtained by microCT were similar to those obtained with standard undecalcified histology. [ABSTRACT FROM AUTHOR]

The goal of this study was to histologically document the effect of two different implant surfaces on the percentage of bone-to-implant apposition achieved with implants placed in human sinus grafts. The influences of implant site and post-grafting delay time were also examined. Nine healthy volunteers were scheduled to undergo posterior maxillary sinus floor augmentation in preparation for delayed implant placement. In addition to the conventional dental implants selected for each case, titanium alloy experimental implants, 2.5 mm in diameter and 8 mm in length, were custom manufactured. Each microimplant was prepared longitudinally with two different surface topographies: machined on one side and MTX microtextured on the other side. A notch prepared across the superior aspect of the implants facilitated placement and provided a reference line between the two surfaces. Patients were divided into two groups that received the experimental microimplants at the time of conventional implant placement: Group A (six patients) received the experimental microimplants in the regenerated lateral wall of the sinus graft 11 months after graft placement, and group B (three patients) received them in the alveolar crest 6 months after graft placement. After 6 months of submerged healing, all experimental and conventional implants appeared to be clinically osseointegrated. Histologic analysis revealed that the mean bone-to-implant apposition was significantly greater with MTX (72.31% ± 17.76%) compared to machined surfaces (38.01% ± 19.32%), regardless of bone quality. The healing time between graft and implant placement and implant location did not statistically impact the percentage of bone-to-implant apposition. [ABSTRACT FROM AUTHOR]

This study looked at a bone-substitute biomaterial (Biostite) used to fill bone defects around immediate implants in humans. Ninety-six peri-implant bone defects were treated without the use of membranes, comparing two groups: group A = filling the defect with Biostite, and group B = no defect fill. After 4 to 6 months of healing, group A revealed higher percentages of implants covered by new, bone-like tissue (67% in group A, 34% in group B). Endochondral osteogenesis was demonstrated histologically in the regenerated tissues in alveolar sites treated, allowing the hypothesis of bone induction from the filling material used. [ABSTRACT FROM AUTHOR]

The effect of the pure-phase beta-tricalcium phosphate (beta-TCP) Cerasorb on bone regeneration was evaluated in hollow titanium cylinders implanted in the posterior jaws of five volunteers. Beta-TCP particles were inserted inside the cylinders and harvested 6 months after placement. The density of the newly formed bone inside the bone-growing chambers measured 27.84% ± 24.67% in test and 17.90% ± 4.28% in control subjects, without a statistically significant difference. Analysis of the histologic specimens revealed that the density of the regenerated bone was related to the density of the surrounding bone. The present study demonstrates the spontaneous healing of infrabony artificial defects, 2.5 mm diameter, in the jaw. The pure beta-TCP was resorbed simultaneously with new bone formation, without interference with the bone matrix formation. [ABSTRACT FROM AUTHOR]

This article introduces a new technique using histomorphometrics to estimate the extent of bone-to-implant contact that might be expected on an implant surface in relation to the quality of the surrounding bone. Two implant surfaces, one machined and one Osseotite, were compared on the same implant in the same patient. Eleven of these custom-made 2-mm-diameter implants were placed in the posterior maxilla and allowed to integrate. After 6 months of nonloaded healing, implants were trephined with surrounding bone tissue and prepared into histologic sections. Digitized images were analyzed at 50x magnification with image-analysis software. Bone surface area was calculated over the entire microscopic field, and the actual bone-to-implant contact for each implant surface was measured. The expected bone-to-implant contact was calculated by superimposing the profile of the implant threads on the bone image a small increment (0.15, 0.5, or 1.0 mm) from the actual implant site and counting the linear amount of bone that would be in contact with the implant surface. The actual bone-to-implant contact for Osseotite was greater than its expected bone-to-implant contact, whereas the actual bone-to-implant contact for the machined surface was mostly lower than the expected values. Thus, the Osseotite surface appears to exert a positive effect on the amount of bone approaching the implant surface and can be described as conductive, while the machined surface is nonconductive. This technique may serve to predict the clinical success that the Osseotite surface will demonstrate in poor-quality bone. [ABSTRACT FROM AUTHOR]

A growing number of clinical studies show that early (2 months) and immediate loading protocols may be predictable. However, they are based on clinical stability only. The aim of this case report was to document the osseointegration status of two Osseotite implants after 2 months of healing in soft bone corresponding to type IV and subjected to two distinct mechanical environments. A completely edentulous patient received a total of 11 Osseotite implants in the mandible. Six were immediately loaded to support a provisional fixed partial denture, and five were left submerged. After 2 months, two submerged and one immediately loaded implants were retrieved and processed for histologic analysis. All immediately loaded implants were clinically stable. One histologic section per implant was obtained. All implants achieved osseointegration. The bone-implant contact was 38.9% for the submerged implant and 64.2% for the immediately loaded one. In the marrow space, both implants were covered by thin, neoformed bone trabeculae. Osseointegration can be achieved after 2 months by Osseotite implants placed in soft bone in the mandible either when immediately loaded and splinted into a provisional denture retained on six implants, or when submerged and unloaded. [ABSTRACT FROM AUTHOR]

The aim of the present work was the evaluation of implant stability and periimplant bone reaction by histologic and clinical evaluation after therapeutic orthodontic loads. Forty-one adult patients received titanium implants as an orthodontic anchorage device; 12 patients received a retromolar or palatal implant to obtain tooth movement. Seven implants were removed at the end of the orthodontic therapy, after 2, 4, 6, and 12 months of orthodontic load, and processed for histologic examination. It was possible to distalize maxillary and mandibular molars and a group of teeth (molars and premolars), and to obtain tipping, uprighting, intrusion, extrusion, and transfer of anchorage in other parts of the mouth. The results showed that orthodontic therapy is facilitated and quickened by the use of implants. All implants remained stable in the bone up to 12 months of loading, and all were osseointegrated. Microfractures, microcracks, and microcalli were observed around implants that had been placed in both low- and highdensity bone. The remodeling rate was still elevated after 18 months. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to conduct a comparative histometric analysis of bone-implant interface between a rough titanium surface and smooth implants in low-density human jawbone after 3, 6, and 12 months of submerged, undisturbed healing. Six adult volunteer patients undergoing standard implant placement were enrolled in this project. Each patient received 1 smooth and 1 rough implant. After 3, 6, and 12 months, the implants were harvested for histometric analysis. The values of boneimplant contact were the following: 3 months smooth 6.2%, 3 months rough 58.9%, 6 months smooth 3.55%, 6 months rough 72.9%, 12 months smooth 6.7%, and 12 months rough 76.75%. The results showed that in low-density bone the rough surface dramatically enhanced the amount of bone-toimplant contact. Because of the small number of implants examined, definite conclusions cannot be drawn, even though the statistical analysis showed significant differences between the smooth and rough groups (P = .0129; F = 76.065). Nevertheless, a trend was evident in these observations: while a rough implant surface may enhance the rate of osseointegration, it is not able to significantly change the bone density, and an implant placed in low-density bone is at a higher risk of failure when occlusal loading begins. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the characteristics of the bone-to-implant interface of hydroxyapatite-coated and non-coated commercially pure titanium threaded implants after different periods of healing in humans. To eliminate possible variations of the results from differences in bone quality and in surgical techniques used in the different test and control sites, only one half of each implant was coated with hydroxyapatite. The coated portions of the implants showed a tendency toward a higher percentage of direct bone-to-implant contact at each period of healing that was observed, although the small number of specimens does not allow definitive conclusions to be made. [ABSTRACT FROM AUTHOR]

A human histologic study was conducted to compare the percentage of bone-to-implant contact (BIC) at 6 months for Osseotite and machined, commercially pure titanium implant surfaces. To eliminate potential influences caused by differences in bone density at different intraoral locations, 2 mm × 5 mm, threaded, 2-surfaced titanium implants were manufactured; 1 side received the Osseotite surface modification and the opposite side maintained a machined surface. In each of 11 patients, 1 test implant was placed in the posterior maxilla (Types III and IV bone) during conventional dental implant surgery. Following 6 months of unloaded healing, the conventional implants were uncovered, and the test implants and surrounding hard tissue were removed. Histologic analysis indicated that at 6 months of unloaded healing, the mean BIC value for the Osseotite surfaces (72.96% ± 25.13%) was statistically significantly higher (P < 0.05) than the mean BIC value for the machined surfaces (33.98% ± 31.04%). When the BIC values for the machined and Osseotite surface pairs were ranked from high to low based on the machined BIC value range of 93% to 0%, the upper 50th percentile (20 surface pairs) mean BIC value was 86.1% ± 16.7% for the Osseotite surfaces and 60.1% ± 18.3% for the machined surfaces. The lower 50th percentile (19 surface pairs) mean BIC value was 59.1% ± 25.3% for the Osseotite surfaces and 6.5% ± 10.8% for the machined surfaces. Differences between mean BIC values for the 2 surfaces in both the upper and lower 50th percentiles were statistically significant (P < 0.05). The result of this study indicate that in the poorer quality bone typically found in the posterior maxilla, a statistically significantly higher percentage of bone contacts Osseotite surfaces when compared to opposing machined surfaces on the same implant. [ABSTRACT FROM AUTHOR]