Adenosquamous carcinoma of the tongue: report of a case with histochemical, immunohistochemical, and ultrastructural study and review of the literature

The histologic examination of dental implants retrieved from humans is important to establish the causal determinants of implant failure, and to compare and validate the results obtained from animal studies. This study presents a retrospective review of the histologic features of 230 implants retrieved in an 8-year period (1989-1996). All the implants were treated to obtain thin (20 to 30 microm) ground sections. The majority of implants were retrieved because of mobility (n=56), peri-implantitis (n=54), or fractures (n=90). Peri-implantitis occurred more frequently before (n=44) than after (n=10) abutment connection. A dense fibrous connective tissue with no inflammatory cells was present at the interface in the implants retrieved for mobility; bone was found only in the most apical part. In many of these implants epithelial cells were present. The main histologic features of peri-implantitis consisted of the presence of a bone sequestrum near the implant, many bacteria present on the implant surface, and an inflammatory infiltrate (macrophages, lymphocytes, and plasma-cells) nearby. Histology showed that in the implants removed for fracture, there was a very high percentage (80 to 100%) of peri-implant bone.     

Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology

The aim of this review was to offer a critical evaluation of the literature and to provide the clinician with scientifically-based diagnostic criteria for monitoring the implant condition. The review presents the current opinions on definitions of osseointegration and implant failure. Further, distinctions between failed and failing implants are discussed together with the presently used parameters to assess the implant status. Radiographic examinations together with implant mobility tests seem to be the most reliable parameters in the assessment of the prognosis for osseointegrated implants. On the basis of 73 published articles, the rates of early and late failures of Br?nemark implants, used in various anatomical locations and clinical situations, were analyzed using a metanalytic approach. Biologically related implant failures calculated on a sample of 2,812 implants were relatively rare: 7.7% over a 5-year period (bone graft excluded). The predictability of implant treatment was remarkable, particularly for partially edentulous patients, who showed failure rates about half those of totally edentulous subjects. Our analysis also confirmed (for both early and late failures) the general trend of maxillas, having almost 3 times more implant losses than mandibles, with the exception of the partially edentulous situation which displayed similar failure rates both in upper and lower jaws. Surgical trauma together with anatomical conditions are believed to be the most important etiological factors for early implant losses (3.60% of 16,935 implants). The low prevalence of failures attributable to peri-implantitis found in the literature together with the fact that, in general, partially edentulous patients have less resorbed jaws, speak in favour of jaw volume, bone quality, and overload as the three major determinants for late implant failures in the Br?nemark system. Conversely, the ITI system seemed to be characterized by a higher prevalence of losses due to peri-implantitis. These differences may be attributed to the different implant designs and surface characteristics. On the basis of the published literature, there appears to be a number of scientific issues which are yet not fully understood. Therefore, it is concluded that further clinical follow-up and retrieval studies are required in order to achieve a better understanding of the mechanisms for failure of osseointegrated implants.     

The relationship of smoking on peri-implant tissue: a retrospective study

The term "peri-implantitis" is used to describe the formation of deep mucosal pockets around dental implants, inflammation of the peri-implant mucosa, and increased resorption of peri-implant bone. It has been speculated that when left untreated, peri-implantitis can result in implant failure. This retrospective study examines a possible correlation between smoking and the appearance of peri-implantitis. The clinical and radiographic observations of 366 implants in 107 patients who smoke were compared with those of a group of 1000 implants in 314 nonsmoking patients. Despite the retrospective nature of this study, a comparison between the two groups was possible. The mean follow-up period, mean patient age, implant locations, and percentages of fixed partial dentures and overdentures were consistent in both groups. There was no significant difference in the mean maxillary and mandibular hygienic indices between the group of smokers and that of nonsmokers. However, the group of smokers showed a higher score in the bleeding index, the mean peri-implant pocket depth, the degree of peri-implant mucosal inflammation, and radiographically discernible bone resorption mesial and distal to the implant. In the maxilla of the smoking group, these observations were significantly higher than both the mandibular observations for smokers and the maxillary observations of the group of nonsmokers (p < 0.01). No differences between the two groups were observed in the mandible. Aside from the systemic effects of tobacco smoking on the human organism, local cofactors seem to be responsible for the higher incidence of peri-implantitis in smokers and have a particularly negative effect on the maxilla. These findings confirm that smokers treated with dental implants have a greater risk of development of peri-implantitis.     

Implant-supported single-tooth replacements: risk of implant and prosthesis failure

Data from 236 patient cases of implant-supported single-tooth replacements in the maxillary anterior region were sequentially recorded and documented. The time in situ ranged from a minimum of five to a maximum of 19 years. Twenty-two implants failed during the observation period. The causes of such failure were peri-implantitis, implant fracture, and trauma. The probability of success according to the Kaplan-Meier method decreased to 0.89 over a period of 10 years. The failure rate for implants replacing lateral incisors was lower than that for implants replacing central incisors. Seventy-six cases were clinically documented for 10 years or more. In 15 cases, replacement of the prosthetic superstructure was necessary during the 10-year period. The course of therapy and clinical follow-up care is described by a multi-state distribution.     

Clinical and histologic evaluation of an active "implant periapical lesion": a case report

A new entity called "implant periapical lesion" has recently been described. This lesion could be the result of, for example, bone overheating, implant overloading, presence of a preexisting infection or residual root fragments and foreign bodies in the bone, contamination of the implant, or implant placement in an infected maxillary sinus. This case report describes a titanium implant that was placed in the maxillary premolar region. A fenestration involving the middle portion of the implant was present. After 7 months, the apical portion of the implant showed radiolucency. This lesion rapidly increased in size and a vestibular fistula appeared. A systemic course of antibiotics was not successful, and the implant was then removed. The histologic examination showed the presence of necrotic bone inside the antirotational hole of the implant. The etiology of the implant failure in this instance could possibly be related to bone overheating associated with an excessive tightening of the implant and compression of the bone chips inside the apical hole, producing subsequent necrosis.     

Histological evaluation of bone reactions to aluminium oxide dental implants in man: a case report

Alumina implants have been shown to possess high biocompatibility. The authors present the case of an aluminium oxide ceramic implant removed because of fracture of the abutment after a 30-month loading period. It was possible to observe microscopically that the implant was covered by highly mineralized mature compact lamellar bone; no connective tissue or inflammatory cells were present at the interface. Osteocytes were observed very close to the bone-implant interface. These features indicate the good biocompatibility of the implant.     

Vicryl-mesh wrap for the implantation of hydroxyapatite orbital implants: an animal model

OBJECTIVE: To evaluate host fibrovascularization of hydroxyapatite orbital implants wrapped in sclera or in Vicryl (polyglactin 910) mesh in a rabbit model. NUMBERS: Eight adult New Zealand white rabbits that received hydroxyapatite orbital implants wrapped in homologous donor sclera (four animals) or Vicryl mesh (four animals). INTERVENTIONS: The rabbits had one eye enucleated and then received a 12-mm hydroxyapatite implant wrapped in sclera or Vicryl mesh. Magnetic resonance imaging (MRI) and bone scintigraphy were done to assess host fibrovascularization of the implant 4, 8, 12 and 20 weeks after implantation. Two animals (one in each group) were killed at each of these times, and the implant was removed for histopathological examination. MAIN OUTCOME MEASURES: Enhancement on MRI, uptake on bone scintigraphy, fibrovascularization seen on histopathological examination. RESULTS: The degree of fibrovascularization was substantial in all the specimens but appeared greater in the Vicryl-mesh-wrapped implants in the first 12 weeks after implantation on both histopathological and MRI studies. At 20 weeks these findings were similar in the two groups. A granulomatous foreign-body giant-cell reaction to both the Vicryl mesh and the implant itself was present up to 8 weeks after implantation. Bone scans showed only grade 1+ activity in all the implants. CONCLUSIONS: Host fibrovascularization in the rabbit appears to occur to a greater degree in Vicryl-mesh-wrapped hydroxyapatite implants than in those wrapped in donor sclera during the first 12 weeks after implantation. Vicryl mesh appears to be an acceptable alternative wrap for the hydroxyapatite implant, eliminating the need for donor sclera and its potential risks of transmissible diseases.     

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.     

Mandibular fracture after endosseous implant placement in conjunction with inferior alveolar nerve transposition: a patient treatment report

A patient with a severely atrophic right posterior mandible had three endosseous implants placed in conjunction with transposition of the inferior alveolar nerve. Three weeks following implant placement surgery, the patient experienced a spontaneous fracture of the mandible involving the two anterior implants. The two implants were removed, and the fracture was treated with open reduction and fixation with titanium mesh. The fracture healed, and the posterior implant integrated. This report suggests that the buccolingual and superior-inferior position of the mandibular canal can increase the possibility of mandibular fracture by increasing the size of the buccal cortical plate that is removed to expose the nerve during surgery.     

Long-term evaluation of the use of coralline hydroxyapatite in orthognathic surgery

PURPOSE: This prospective study was designed to evaluate the long-term clinical and radiographic results of porous block hydroxyapatite (PBHA) used as a synthetic bone graft in orthognathic surgery and craniofacial augmentation. PATIENTS AND MATERIALS: A total of 245 consecutive patients were treated initially. Inclusion criteria for this study included a minimum clinical and radiographic follow-up of 5 years. In addition, all patients with known implant failures were included regardless of whether they met the study criteria. There were 111 patients that met the criteria for inclusion in this study. All patients had undergone orthognathic surgery with rigid fixation and had had inlay or onlay PBHA implants placed. Ninety-six percent of the implants were placed through an intraoral approach. Long-term postoperative radiographs were visually compared with immediate postoperative radiographs for implant position, stability, resorption, and other significant radiographic changes. The clinical examination evaluated for signs and symptoms of infection, wound dehiscence, implant exposure, implant displacement, changes in the overlying mucosa, and development of oronasal or oroantral fistulae. RESULTS: Four hundred seventy-one implants were placed: 403 in the maxilla, 44 in the mandible, and 24 in the periorbital region. There were 289 implants placed in direct communication with the maxillary sinus. The average follow-up time was 7.2 years (range, 5.0 to 10.3 years). Twenty-three implants (4.9%) were removed during the evaluation period. Lateral maxillary wall grafting had 95.7% success, with nine implants being lost in three patients. One chin implant was removed because of dissatisfaction with the aesthetics. Seven (14%) midpalatal implants used for maxillary expansion were lost, primarily because of exposure of the implant to the oral or nasal cavity at the time of surgery. When PBHA was used for alveolar cleft grafting, there was a 100% failure rate. CONCLUSION: The use of PBHA as a bone graft substitute in orthognathic surgery and for facial augmentation showed a high percentage of success and efficacy. However, adequate soft tissue coverage in the nasal floor and on the palate are paramount for success of midpalatal implants. PBHA should not be used for alveolar cleft grafting. Rigid fixation for inlay implants in the maxilla is important to provide stress shielding of the material and minimize micromovement during the initial healing phase.     

Reconstruction of residual alveolar cleft defects with one-stage mandibular bone grafts and osseointegrated implants

PURPOSE: This study evaluates a treatment regimen for reconstruction of residual maxillary alveolar cleft defects consisting of mandibular bone grafting and immediate implant installation. PATIENTS AND METHODS: Sixteen cleft patients (five female and 11 male) had residual cleft defects of the alveolar ridge reconstructed with bone grafts from the mandibular symphyseal region. The bone graft was pretapped at the donor site before fixation in the residual ridge with Br?nemark implants. Twenty implants were installed according to this concept. The period of observation ranged from 36 to 69 months, with a mean of 48 months after implant installation. RESULTS: Five patients developed wound dehiscenses that resulted in total or partial bone graft sequestration. Two implants were lost, one due to sequestration and the other due to mobility at the abutment procedure; 18 implants were still well functioning at the end of the observation period. However, all patients showed significant periimplant bone resorption after this one-stage treatment. CONCLUSION: Because of the observed complication rate, the one-stage procedure may not be optimal for reconstructing residual cleft defects.     

Clinical and microbiological status of osseointegrated implants

Peri-implantitis, an inflammatory response around implants, has a poorly defined etiology and pathogenesis. To better understand the role of specific microorganisms in this disease process, clinical and microbiological parameters were examined in 24 patients with 98 osseointegrated implants. Sites were evaluated for probing depth (PD), plaque/calculus index (PI), gingival bleeding index (GBI), mobility, and crevicular fluid flow rate (CFFR). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in subgingival plaque were identified by latex agglutination assays. Clinically, a statistically significant correlation (P < 0.001) was observed between probing depth and the length of time an implant was present. Mobility was also significantly greater (P < 0.001) in the maxillary than in the mandibular implants. Subgingival sites harboring one of the three microorganisms had significantly greater PD, GBI, and CFFR than non-colonized sites. Implants in partially edentulous patients more frequently were colonized with P. gingivalis/P. intermedia than edentulous patients. The incidence of these microorganisms also correlated with fixture longevity. Implants present for 3 to 4 years had a significantly greater frequency of test microorganisms than implants present for 1 to 2 years. These findings suggest that microbial pathogens associated with periodontitis occur more commonly around implants exhibiting gingival inflammation (GBI) and may contribute to peri-implantitis.     

Loaded and nonloaded titanium versus hydroxyapatite-coated threaded implants in the canine mandible

A commercially pure titanium threaded implant was compared to a hydroxyapatite-coated threaded implant of similar geometric design and dimensions in the canine model. Bilateral posterior implants supported fixed prostheses, and some implants in the same mandibles served as unloaded control implants. Implants were evaluated clinically, radiographically, and histomorphometrically at the light microscope level to detect any differences in bone response to loaded conditions. No statistically significant differences were found between the two implant designs under loaded or nonloaded conditions with regard to mobility, probing depth, percentage of osseointegration, and crestal bone position.     

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.     

Treatment of peri-implantitis using guided bone regeneration and bone grafts, alone or in combination, in beagle dogs. Part 1: Clinical findings and histologic observations

The purpose of this study was to evaluate and compare the treatment of ligature-induced peri-implantitis using guided bone regeneration and two bone grafts alone and in combination. Mandibular premolars and first molars were extracted from four beagle dogs and after 3 months of healing, three Br?nemark implants were placed on each side of the mandibles. Following abutment connection 3 months later, experimental peri-implantitis was induced by tying plaque-retentive ligatures around all abutments. Ligatures and abutments were removed after 3 months, and bony defects measured and treated with either: (1) debridement only; (2) debridement plus resorbable hydroxyapatite; (3) debridement plus canine freeze-dried demineralized bone; (4) debridement plus guided bone regeneration; (5) debridement plus resorbable hydroxyapatite and guided bone regeneration; or (6) debridement plus canine freeze-dried demineralized bone and guided bone regeneration. Pretreatment and 4-month-posttreatment comparison revealed a significant but variable degree of clinically appreciable hard tissue fill with all treatment procedures. Guided bone regeneration procedures resulted in the greatest fill, followed by bone grafts alone and flap debridement. There was no significant difference between guided bone regeneration and both guided bone regeneration/graft combinations; therefore, guided bone regeneration procedures appear to be a predictable treatment for plaque-induced peri-implant defects.     

Lesions in the dentate hilum and CA2/CA3 regions of the rat hippocampus produce cognitive deficits that correlate with site-specific glial activation

The aim of the present experimental investigation was to study the morphological and dimensional changes of bone, augmented at titanium implants by a membrane technique, taking place after membrane removal. In 12 rabbits, screw-shaped titanium implants were inserted in the tibial metaphyses in such a way that 5 threads became uncovered with bone. Surgery was performed on 2 occasions in order to retrieve specimens with different follow-up times. An e-PTFE barrier and a titanium device were used to provide space for bone formation. In 1 tibia of each rabbit, the membranes and spacers were removed after 8 weeks of healing, and the implants followed for 16 more weeks. Impressions were taken at day 0 and after 8 and 24 weeks of healing and plaster models were produced. In the contralateral tibiae, implants were inserted either 16 or 8 weeks prior to sacrifice. Measurements were made on the plaster models in 3 dimensions at 35 points around each implant in a coordinate measuring machine. Specimens taken 8, 16 and 24 weeks after insertion were analysed by means of light microscopical morphometry. The coordinate measurements showed that, in mean, 1.92 mm of bone had been formed during the first 8 weeks. A statistically significant loss of the height of the newly formed bone (0.70 mm) and thereby reduction of bone volume was found 24 weeks postoperatively. The volume decrease of the newly formed bone was more pronounced beside the implants than over the implant body. The histology showed that woven bone had been formed at the implants after 8 weeks. Further bone formation and remodelling and a net increase of mineralized bone were seen. The degree of bone-implant contact and bone area in the threads increased with time. The present study showed that coordinate measurements on plaster models, obtained from the experimental areas, in combination with histology, form a useful technique to study long-term changes of augmented bone. It was found that bone formed by a barrier membrane technique, decreased in volume during a 16-week follow-up period after barrier removal. Less dimensional changes were observed for the bone formed over the implant body, indicating that a solid surface may have a stabilizing effect on the augmented bone.     

Biodegradable interlocking nails for fracture fixation

Serious problems such as stress shielding, allergic reactions, and corrosion are associated with the use of metallic fracture fixation devices in fractured long bones. Metal implants often are removed during a second retrieval operation after fracture healing has completed. A biocompatible implant that degrades slowly during implantation would obviate the need for a second operation and save the patient from considerable physical, psychologic, and financial discomfort. The biodegradable implant must provide the fractured limb sufficient support for a certain time, allowing early loading. A gradual transfer of load from the biodegradable implant to the bone would result in a better product of bone healing and avoid stress shielding. In an animal model using adult sheep, two types of biodegradable polymer interlocking nails were tested in comparison with a stainless steel interlocking nail. Fracture healing, mechanical properties of the bones, degradation behavior in vivo and in vitro, and tissue response were monitored during a 2 1/2-year followup study. To detect shifts in acid base relations caused by the release of acid compounds, pH measurements were performed. Fracture healing was unimpaired, and the mechanical test results of all three groups were excellent. Histologic analysis showed a mild inflammatory response, but no pH shifts were observed. The results of this study justify additional research on these promising materials.     

Histological and biomechanical analysis of bone and interface reactions around hydroxyapatite-coated intramedullary implants of different stiffness: a pilot study on the goat

We hypothesized that reduced stem stiffness of orthopaedic implants contributes to a high risk of loosening, since interface stresses and relative motions may exceed a tolerable range. To study this hypothesis, three types of load-bearing implant with different stiffnesses were inserted into the tibia of the goat. Histological analysis was performed of bone repair after insertion of the implant, bone ingrowth, interface disruption and loosening. A finite element model of the configuration provided the quantitative range of interface stresses and relative motions for the present experiment. The implants were made out of stainless steel, hollow titanium and a thin titanium core covered with a polyacetal coating. The stiffness ratios of these implants were approximately 10:4:1, respectively. All implants were coated with a layer of hydroxyapatite (HA) in order to minimize the possible biological effects of the different implant materials. Irrespective of the type of implant, there was a repair phase that lasted 6-12 weeks. The stiff implants functioned well. Large areas of bone bonding to the HA layer were found after the repair phase at 12 weeks postoperatively. After 24 weeks, some signs of loosening were observed. More loosening occurred with the hollow titanium and polyacetal implants, mainly during the repair phase. Three hollow titanium and three polyacetal coated implants survived this period, and were killed after 24 weeks. The integrity of the HA layer at the bone-implant interface of the titanium implants was good. In the polyacetal implants, the repair reaction of the cortical bone was incomplete. Bone ingrowth into HA was largely lacking. In conclusion, we found significant differences in the repair and interface reactions around implants of different stiffness. Stiff implants showed favourable initial interface conditions for bone ingrowth. Intermediate and flexible implants provoked unfavourable interface conditions for initial bone ingrowth. The finite element study showed that the flexible stems produce larger micromotions and higher interface stresses at the bone-prosthesis interface than the stiff stems, indicating an explanation for the histological findings.     

Altered patterns of DNA methylation on chromosomes from leukemia cell lines: identification of 5-methylcytosines by indirect immunodetection

The feasibility of implant treatment in patients after oral ablative tumor surgery has not yet been investigated with consideration of the requisite high periodontal standards. A report on this topic has to deal not only with implant survival but also with implant health, bone response, soft tissue health, failure pattern, time of failure, and ease of restoration. For the assessment of an implant system, an overview must be accomplished that takes into account the different restorations used and their interaction with the implant system that was used. This study presents the Bone-Lock implant system (Howmedica Leibinger GmbH, Freiburg, Germany) in a retrospective investigation after 5 years of follow-up with special emphasis on the prosthetic restorations used following resection of oral malignancies. From early in 1990 through June 1996, we inserted 210 dental endosteal Bone-Lock implants (58 patients) after oral tumor resectioning. Included in the study were 45 patients with 162 implants and prosthetic restorations that had been loaded for 1 year (dentures retained by telescopic or bar-clip or ball attachments, implant-supported prostheses, tooth-to-implant connected bridges). Regular follow-up consisted of evaluation of the Plaque Index (Silness and L?e) and of the Sulcus Bleeding Index (L?e), measurements of pocket probing depth, implant mobility (by means of the Periotest method), bone resorption (according to X-ray findings), and a questionnaire that registered patient satisfaction. The results were evaluated for each restoration and were compared with baseline standards. The overall 5-year survival rate was 83.2%. For implants that had been in place for over 365 days, the survival rate was 93%. The investigation showed that after resection of oral malignancies, patients could be treated with dental implants and superstructures with long-term efficacy similar to that found in healthy subjects considering internationally accepted standards. Implant treatment in tumor patients appeared to offer the most positive periodontic results when use of bar-clip or telescope-retained overdentures was involved. The patient satisfaction level with the described prosthodontic treatment was satisfactory.     

Resonance frequency analysis: measuring implant stability and osseointegration

Achievement and maintenance of implant stability are prerequisites for long-term positive outcomes for osseointegrated implants. Thus, implant stability is the key to clinical success. Until recently, it was not possible for the clinician to predictably distinguish implants with different degrees of stability. Because there seems to be a correlation between implant failure and bone properties, it is possible that clinically firms implants with poor stability are more prone to failure than more stable implants. This article discusses the development and possible future use of a novel technique for clinical measurement of implant stability and osseointegration--resonance frequency analysis.