Clinical and histologic evaluation of calcium-phosphate bone cement in interproximal osseous defects in humans: a report in four patients

This study evaluated the clinical and histologic results of a calcium phosphate bone cement in the treatment of human periodontal intraosseous defects. Four patients with chronic advanced periodontitis in whom treatment with complete dentures was planned were recruited. The cement was implanted in one defect per subject with a presurgical probing depth of at least 7 mm and a radiographic bone defect of 4 mm or more. Patients were seen every 2 weeks for periodontal maintenance. At 6 months, clinical measurements were repeated and the tooth was removed en bloc for histologic processing. Results demonstrated that all defects resulted in probing depth reduction and, at three of the four defects, in clinical attachment level gain. However, no site showed periodontal regeneration. There was no new bone formation. New cementum and connective tissue were limited to 0.2 mm or less. Large deposits of the bone cement were noted encapsulated in connective tissue.

Regulation of angiogenesis during osseointegration by titanium surface microstructure and energy

Rough titanium (Ti) surface microarchitecture and high surface energy have been shown to increase osteoblast differentiation, and this response occurs through signaling via the alpha(2)beta(1) integrin. However, clinical success of implanted materials is dependent not only upon osseointegration but also on neovascularization in the peri-implant bone. Here we tested the hypothesis that Ti surface microtopography and energy interact via alpha(2)beta(1) signaling to regulate the expression of angiogenic growth factors. Primary human osteoblasts (HOB), MG63 cells and MG63 cells silenced for alpha(2) integrin were cultured on Ti disks with different surface microtopographies and energies. Secreted levels of vascular endothelial growth factor-A (VEGF-A), basic fibroblast growth factor (FGF-2), epidermal growth factor (EGF), and angiopoietin-1 (Ang-1) were measured. VEGF-A increased 170% and 250% in MG63 cultures, and 178% and 435% in HOB cultures on SLA and modSLA substrates, respectively. In MG63 cultures, FGF-2 levels increased 20 and 40-fold while EGF increased 4 and 6-fold on SLA and modSLA surfaces. These factors were undetectable in HOB cultures. Ang-1 levels were unchanged on all surfaces.Media from modSLA MG63 cultures induced more rapid differentiation of endothelial cells and this effect was inhibited by anti-VEGF-A antibodies. Treatment of MG63 cells with 1 alpha,25(OH)(2)D3 enhanced levels of VEGF-A on SLA and modSLA.Silencing the alpha(2) integrin subunit increased VEGF-A levels and decreased FGF-2 levels. These results show that Ti surface microtopography and energy modulate secretion of angiogenic growth factors by osteoblasts and that this regulation is mediated at least partially via alpha(2)beta(1) integrin signaling.

Regeneration of periodontal tissues: guided tissue regeneration

The concept that only fibroblasts from the periodontal ligament or undifferentiated mesenchymal cells have the potential to re-create the original periodontal attachment has been long recognized. Based on this concept, guided tissue regeneration has been applied with variable success to regenerate periodontal defects. Quantitative analysis of clinical outcomes after guided tissue regeneration suggests that this therapy is a successful and predictable procedure to treat narrow intrabony defects and class II mandibular furcations, but offers limited benefits in the treatment of other types of periodontal defects.

Cellular effects of enamel matrix derivative are associated with different molecular weight fractions following separation by size-exclusion chromatography

BACKGROUND

Enamel matrix derivative (EMD) was shown to enhance soft tissue healing and regeneration of the periodontium; however, the mechanisms of this action are unknown. It is assumed that amelogenin, the most abundant protein in EMD, is the protein primarily responsible for the effects of EMD. The purpose of this study was to fractionate EMD and associate its specific cellular effects with different molecular weight fractions following size-exclusion chromatography.

METHODS

Freshly dissolved EMD was fractionated by gel filtration, and forty-five 7-ml fractions were collected, desalted, lyophilized, and resuspended. These fractions were analyzed for their effects on the differentiation of osteoprogenitor cells (C2C12) and the proliferation and differentiation of human microvascular endothelial cells (HMVECs). Alkaline phosphatase activity (C2C12) was measured as a marker for osteogenic differentiation before and after preincubation of the fractions with the bone morphogenetic protein (BMP) decoy receptor, noggin. Angiogenesis (HMVEC) was evaluated as a marker for endothelial cell differentiation. Enzymographic assays used polyacrylamide gels copolymerized with denatured type I collagen to determine gelatinolytic activities in each fraction.

RESULTS

EMD fractionated into three major protein peaks following size exclusion chromatography with cross-linked dextran particle matrix. Peak I was associated with the column void volume, whereas peak III eluted near the salt volume. Peak II eluted between these two peaks. Proliferation and angiogenic activities were associated with peaks II and III for the microvascular cells. The differentiation of osteoprogenitor cells, indicated by alkaline phosphatase activity, was induced by EMD components present in peak I and the leading edge of peak II. The additional observation that this differentiation was inhibited by prior treatment of the fractions with noggin suggested the activity was induced by BMP rather than amelogenin or other unknown proteins. Gelatinolytic activities were detected in the early fractions of peaks I and II of gel-fractionated EMD.

CONCLUSIONS

The cellular activities stimulated by EMD are not associated with a single molecular weight species. The fact that noggin abolishes C2C12 alkaline phosphatase activity suggests that effects on osteoprogenitor cell differentiation are the result of a BMP-like protein(s), whereas effects on proliferation and angiogenesis are associated with lower molecular weight species present in peaks II and III. Finally, unheated EMD displays gelatinolytic activities that are also detectable following size-exclusion separation of its constituents. The masses of these activities were consistent with those reported for latent and active matrix metalloproteinase-20.

The biologic width around titanium implants: histometric analysis of the implantogingival junction around immediately and early loaded implants

This study compared the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants as well as conventionally loaded one-piece implants. Comparisons of the peri-implant soft tissue dimensions were made among four different loading periods. Forty-eight titanium sandblasted/acid-etched implants were placed in four foxhounds. The implants were placed at four time periods in groups of three. The first group (A) had implants placed 3 months before the placement of restorations. Further groups of three implants each were placed at 21 days (group B), 10 days (group C), and 2 days (group D) before restoration. Three months after abutment connection, all dogs were sacrificed. Histometric analysis of the undecalcified histologic sections included dimensional measurements of the sulcus depth plus junctional epithelium, the connective tissue contact area, and recession measured from the interface to the gingival margin. No statistically significant differences were observed among the four groups. The data suggest that the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants are similar to those around conventionally loaded one-piece implants and comparable to the dimensions of the biologic width around natural teeth.

Histological and clinical evaluation of recombinant human platelet-derived growth factor combined with beta tricalcium phosphate for the treatment of human Class III furcation defects

Four patients with chronic advanced periodontitis participated in this study. At least one mandibular first molar had to have a hopeless periodontal and prosthetic prognosis. Clinical measurements were made, and the furcation defects were surgically exposed. A notch was placed through the calculus on both the mesial and distal roots. The furcal area was root planed with diamond-tip ultrasonic instruments. The furcations were grafted with a combination of recombinant human platelet-derived growth factor and beta tricalcium phosphate. A collagen barrier for guided tissue regeneration was used on both the facial and lingual surfaces. The flaps were coronally positioned and sutured. All patients were followed at 2-week intervals for 6 months. At 6 months, all teeth demonstrated a reduction in probing depth and a gain in clinical attachment. One tooth demonstrated a Class II furcation involvement, while through-and-through furcation involvement was still evident on the other three experimental teeth. The teeth were removed en bloc and processed for histologic evaluation. Three root surfaces demonstrated periodontal regeneration, an additional three showed new attachment, and one surface revealed junctional epithelium as measured from the base of the calculus notch. The notch area could not be identified on one surface of one specimen.

Potential of chemically modified hydrophilic surface characteristics to support tissue integration of titanium dental implants

In the past, several modifications of specific surface properties such as topography, structure, chemistry, surface charge, and wettability have been investigated to predictably improve the osseointegration of titanium implants. The aim of the present review was to evaluate, based on the currently available evidence, the impact of hydrophilic surface modifications of titanium for dental implants. A surface treatment was performed to produce hydroxylated/hydrated titanium surfaces with identical microstructure to either acid-etched, or sand-blasted, large grit and acid-etched substrates, but with hydrophilic character. Preliminary in vitro studies have indicated that the specific properties noted for hydrophilic titanium surfaces have a significant influence on cell differentiation and growth factor production. Animal experiments have pointed out that hydrophilic surfaces improve early stages of soft tissue and hard tissue integration of either nonsubmerged or submerged titanium implants. This data was also corroborated by the results from preliminary clinical studies. In conclusion, the present review has pointed to a potential of hydrophilic surface modifications to support tissue integration of titanium dental implants.

Inflammation and bone loss in periodontal disease

Inflammation and bone loss are hallmarks of periodontal disease (PD). The question is how the former leads to the latter. Accumulated evidence demonstrates that PD involves bacterially derived factors and antigens that stimulate a local inflammatory reaction and activation of the innate immune system. Proinflammatory molecules and cytokine networks play essential roles in this process. Interleukin-1 and tumor necrosis factor-alpha seem to be primary molecules that, in turn, influence cells in the lesion. Antigen-stimulated lymphocytes (B and T cells) also seem to be important. Eventually, a cascade of events leads to osteoclastogenesis and subsequent bone loss via the receptor activator of nuclear factor-kappa B (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) axis. This axis and its regulation are not unique to PD but rather are critical for pathologic lesions involving chronic inflammation. Multiple lines of evidence in models of PD clearly indicate that increases in RANKL mRNA expression and protein production increase the RANKL/OPG ratio and stimulate the differentiation of macrophage precursor cells into osteoclasts. They also stimulate the maturation and survival of the osteoclast, leading to bone loss. OPG mRNA expression and protein production do not generally seem to be increased in the periodontitis lesion. Studies of RANKL and OPG transgenic and knockout animals provide further support for the involvement of these molecules in the tissue loss observed in PD. Ironically, periodontal practitioners have focused on the bacterial etiology of PD and believed that plaque removal was aimed at eliminating specific bacteria or bacterial complexes. However, it seems that the reduction of inflammation and attenuation of the host's immune reaction to the microbial plaque, eventually leading to a decrease in the ratio of RANKL/OPG and a decrease in associated bone loss, are the actual and desired outcomes of periodontal therapy. Future therapeutic options are likely to have regulation of the RANK-RANKL-OPG axis as their goal.

Human histologic and clinical evaluation of recombinant human platelet-derived growth factor and beta-tricalcium phosphate for the treatment of periodontal intraosseous defects

This study histologically evaluated recombinant human platelet-derived growth factor-BB (rhPDGF-BB) in combination with beta-tricalcium phosphate (beta-TCP) for the treatment of human intraosseous periodontal defects. Eight patients, each with two teeth treatment planned for extraction, were enrolled. Presurgical measurements included probing depth, clinical attachment level, and recession. Initial surgery consisted of flap reflection, debridement, placement of a root notch through the base of calculus, scaling and root planing, root biomodification with 50 mg/mL tetracycline, grafting with rhPDGF-BB + beta-TCP, and complete wound closure. One tooth in each patient was treated with 0.3 mg/mL of rhPDGF-BB + beta-TCP, and the other tooth was treated with 1.0 mg/mL of rhPDGF-BB + beta-TCP. After a minimum of 6 months of healing, postsurgical clinical measurements were made, and teeth were removed en bloc. Soft tissue healing was uneventful. Histologic evaluation demonstrated new bone, cementum, and periodontal ligament coronal to the reference notch in 13 of the 16 teeth. Six of the eight 0.3-mg/mL sites and seven of the eight 1.0-mg/mL sites demonstrated periodontal regeneration. This study provides proof of principle that 0.3 mg/mL and 1.0 mg/mL of rhPDGF-BB and beta-TCP can promote periodontal regeneration in human intraosseous periodontal defects.

Bone apposition around two different sandblasted and acid-etched titanium implant surfaces: a histomorphometric study in canine mandibles

PURPOSE

The aim of this study was to evaluate bone apposition to a modified sandblasted and acid-etched (SLA) implant surface (modSLA) in the canine mandible as compared with the standard SLA surface.

MATERIAL AND METHODS

In this experimental study, all mandibular premolars and first molars were extracted bilaterally in five foxhounds. After a healing period of 6 months, each side of the mandible received six randomly assigned dental implants alternating between the standard SLA and modSLA surface. The dogs were sacrificed at 2 weeks (n=2) or 4 weeks (n=3) after implant placement. Histologic and histomorphometric analyses were then performed for each implant.

RESULTS

The microscopic healing patterns at weeks 2 and 4 for the two implant types with the standard SLA and modSLA surfaces showed similar qualitative findings. New bone tissue had already established direct contact with implant surfaces after 2 weeks of healing. The mean percentage of newly formed bone in contact with the implant (BIC) was significantly greater for modSLA (28.2+/-7.9%) than for SLA (22.2+/-7.3%) (P<0.05). This difference was no longer evident after 4 weeks. An increase in BIC for both implant surface types occurred from weeks 2 to 4. This increase was statistically significant when compared with SLA at 2 weeks (P<0.05), but not when compared with modSLA at 2 weeks.

CONCLUSION

The data from the present study demonstrate significantly more bone apposition for the modSLA surface than the standard SLA surface after 2 weeks of healing. This increased bone apposition may allow a further reduction of the healing period following implant placement for patients undergoing early loading procedures.

Osteoblast response to fluid induced shear depends on substrate microarchitecture and varies with time

Osteoblasts are exposed to fluid shear in vivo but the effects are not well understood, particularly how substrate properties or length of exposure modify the response. Short exposure (1 h) to shear reduces the stimulatory effect of micron-scale surface structure on osteoblast differentiation, but the effects of longer term exposures are not known. To test the hypothesis that substrate-dependent responses of osteoblasts to shear depend on the length of exposure to fluid flow, MG63 osteoblasts were grown on tissue culture glass, which has an average roughness (Ra) < 0.2 microm; machined Ti disks (PT, Ra < 0.6 microm); Ti disks with a complex microarchitecture [sand blasted acid etched (SLA), Ra = 4-5 microm); and Ti plasma-sprayed surfaces [Ti via plasma spray (TPS), Ra = 7 microm]. Confluent cultures were exposed to pulsatile flow at shear forces of 0, 1, and 14 dynes/cm(2) for 0, 6, 12, and 24 h. Shear reduced cell number on all surfaces, with greatest effects on TPS. Shear had no effect on alkaline phosphatase on smooth surfaces but increased enzyme activity on SLA and TPS in a time-dependent manner. Its effects on osteocalcin, TGF-beta1, and PGE(2) in the conditioned media were greatest on these surfaces as well. Responses to fluid-induced shear were blocked by the general Cox inhibitor indomethacin and the Cox-2 inhibitor meloxicam, indicating that response to shear is mediated by prostaglandin produced via a Cox-2 dependent mechanism. These results show that the effects of fluid induced shear change with time and are substrate dependent, suggesting that substrate microarchitecture regulates the osteoblast phenotype and effects of shear are determined by the maturation state of the responding population.

Enhanced implant stability with a chemically modified SLA surface: a randomized pilot study

PURPOSE

Chemical modification to a sandblasted, large-grit, acid-etched (SLA) implant surface has been shown to enhance the rate of osseointegration. The goal of the present study was to examine changes in stability for implants with a chemically modified SLA surface and to compare their outcomes to those of control implants.

MATERIALS AND METHODS

A randomized controlled trial was conducted with 31 patients. Each patient received 2 implants with the same physical properties but with surfaces that were chemically different. The control implants had a standard SLA surface, while the test implants had a chemically modified surface. Resonance frequency analysis was assessed weekly over the first 6 weeks following implant placement.

RESULTS

All implants proved clinically successful, allowing for restoration. Most implants were placed in the mandible (50 of 62). A shift in implant stability from decreasing stability to increasing stability (P < .001), occurred after 2 weeks for the test implants and after 4 weeks for the control implants.

CONCLUSION

The findings from this pilot study provide clinical support for the potential for chemical modification of the SLA surface to alter biologic events during the osseointegration process and demonstrate levels of short-term clinical success similar to those observed for implants with an SLA surface.

Purification and analysis of a 5kDa component of enamel matrix derivative

High performance liquid chromatography (HPLC) methods were used to analyse a 5kDa component purified from enamel matrix derivative (EMD), the active ingredient in Emdogain, a commercial product for periodontal tissue regeneration. After initial purification by size-exclusion chromatography (SEC) on a 100 cm x 5 cm column (Bio-Gel P-30 Fine, 280 nm), collected fractions were analysed by size-exclusion HPLC (SE HPLC; TSK-Gel Super SW2000, 220 nm). The fractions containing only the 5kDa component were analysed by reversed-phase high-pressure chromatography (RP HPLC; YMC-Pack ODS-A, 200 nm), revealing four peaks of the 5kDa component. From 1200 mg of EMD (of which 9% is the 5kDa component), approximately 65 mg of lyophilised 5kDa component were obtained, corresponding to a recovery of 60%. The SE HPLC method was mainly suitable for qualitative analysis, whereas the RP HPLC method was appropriate for both qualitative and quantitative analysis.

The effect of matrix bound parathyroid hormone on bone regeneration

INTRODUCTION

Autogenous bone is the most successful bone-grafting material; however, multiple disadvantages continue to drive developments of improved methods for bone regeneration.

AIM

The aim of the present study was to test the hypothesis that an arginine-glycine-aspartic acid (RGD) modified polyethylene glycol-based matrix (PEG) containing covalently bound peptides of the parathyroid hormone (PTH(1-34)) enhances bone regeneration to a degree similar to autogenous bone.

MATERIAL AND METHODS

Six American foxhounds received a total of 48 cylindrical titanium implants placed in the mandible between the first premolar and the second molar. Five, respectively, 7 months following tooth extraction, implants were placed into the center of surgically created defects. This resulted in a circumferential bone defect simulating an alveolar defect with a circular gap of 1.5 mm. Four treatment modalities were randomly allocated to the four defects per side: (1) PEG-matrix containing 20 microg/ml of PTH(1-34), and 350 microg/ml cys-RGD peptide, (2) PEG alone, (3) autogenous bone and (4) empty defects. Histomorphometric analysis was performed 4 and 12 weeks after implantation. The area fraction of newly formed bone was determined within the former defect and the degree of bone-to-implant contact (BIC) was evaluated both in the defect region and in the apical region of the implant. For statistical analysis ANOVA and subsequent pairwise Student's t-test were applied.

RESULTS

Healing was uneventful and all implants were histologically integrated. Histomorphometric analysis after 4 weeks showed an average area fraction of newly formed bone of 41.7+/-1.8% for matrix-PTH, 26.6+/-4.1% for PEG alone, 43.9+/-4.5% for autogenous bone, and 28.9+/-1.5% for empty defects. After 12 weeks, the respective values were 49.4+/-7.0% for matrix-PTH, 39.3+/-5.7% for PEG alone, 50.5+/-3.4% for autogenous bone and 38.7+/-1.9% for empty defects. Statistical analysis after 4 and 12 weeks revealed significantly more newly formed bone in the PTH(1-34) group compared with PEG alone or empty defects, whereas no difference could be detected against autogenous bone. Regarding BIC no significant difference was observed between the four treatment groups neither at 4 nor at 12 weeks.

CONCLUSION

It is concluded that an RGD-modified PEG hydrogel containing PTH(1-34) is an effective matrix system to obtain bone regeneration.

Evaluation of two different resonance frequency devices to detect implant stability: a clinical trial

BACKGROUND

Resonance frequency analysis (RFA) provides a non-invasive assessment of implant stability. The established RFA device uses electronic technology, whereas a recently developed device uses magnetic technology. The goal of this clinical trial was to evaluate the ability of the magnetic RFA device to detect changes in stability during early healing following implant placement and to determine whether the implant stability quotient (ISQ) values obtained correlated with those made with the electronic device.

METHODS

RFA assessments were performed using electronic- and magnetic-based devices on 34 non-submerged titanium dental implants in 17 patients. Each patient received two implants in the posterior maxilla or mandible. Implant stability was measured at placement and weekly until week 6, when implants received provisional crowns, and at 12 weeks, when definitive crowns were cemented. During each visit, measurements were taken three times and averaged to obtain a single representative ISQ for each device.

RESULTS

At placement, the mean ISQ obtained with the electronic device was 61.9 (95% confidence interval [CI], 59.4 to 64.3); it increased to 63.2 (95% CI, 61.2 to 65.2) at 12 weeks. With the magnetic device, the mean ISQs were 70.6 (95% CI, 68.4 to 72.8) and 75.9 (95% CI, 74.2 to 77.7), respectively. Both devices indicated a pattern of decreased mean stability from 1 to 3 weeks post-placement, small fluctuations in mean ISQ from 3 to 6 weeks, and significantly increased mean stability from 6 to 12 weeks. For the complete set of implant measures across all weeks, the paired electronic and magnetic ISQ values correlated significantly (r = 0.52; P <0.001).

CONCLUSIONS

This study demonstrates that changes in implant stability measured with the newer magnetic device correlate well with those found with the electronic device. Both devices confirmed the initial decreases in implant stability that occur following placement and identified an increase in stability during the first 6 weeks of functional loading.

In vitro effects of enamel matrix derivative on microvascular cells

BACKGROUND

Periodontal regeneration requires a coordinated series of events that includes not only the recruitment of periodontal ligament (PDL)-specific cells, but vascular cells as well. The mechanisms of action of enamel matrix derivative (EMD) are poorly understood, and its effects on vascular cells are unknown. The objective of this study was to examine the extent to which EMD affects angiogenesis and PDL cell recruitment.

METHODS

The effects of EMD on human microvascular endothelial cells (HMVECs) were determined by examining proliferation, chemotaxis, angiogenesis, and migration. Proliferation was determined using water-soluble tetrazolium salt (WST)-1 reagent. Chemotaxis was determined using microporous-culture well inserts. Angiogenesis was assessed on plates containing matrigel. The effects of HMVECs on the migration of PDL cells were assessed by evaluating PDL cell outgrowth from collagen gels cultured in the presence of HMVECs on fibrin matrix and surrounded by fibronectin-containing fibrin clots at 24 hours. Effects of EMD on PDL expression of vascular endothelial cell (VEGF) types (A, B, C, and D) and isoforms were determined using reverse transcription-polymerase chain reaction (RT-PCR). Production of VEGF, platelet-derived growth factor (PDGF)-AA, PDGF-BB, PDGF-AB, and transforming growth factor (TGF)-beta1 by EMD-stimulated PDL cells was assessed quantitatively in conditioned media using specific enzyme-linked immunosorbent assays (ELISAs).

RESULTS

EMD at concentrations <50 microg/ml resulted in significant (P <0.05) stimulation of HMVEC proliferation. Compared to baseline, EMD also stimulated a 100% increase in HMVEC chemotaxis when PDL cells were present (P <0.05). All doses of EMD tested (25, 50, and 100 microg/ml) increased angiogenesis in vitro. HMVECs, in combination with EMD at a concentration of 100 microg/ml, stimulated a 750% increase in migration of PDL cells from collagen gels into fibrin clots compared to controls when neither was present. RT-PCR results indicated that PDL cells expressed VEGF-A, -B, and -C and multiple isoforms of VEGF-A, including VEGF(121), VEGF(165), and VEGF(189), whether or not EMD was present in the culture media. ELISAs determined a 400% increase in VEGF concentration by PDL C cells in EMD-stimulated conditioned media and a similar increase in TGF-beta(1)-stimulated media.

CONCLUSIONS

It is likely that EMD stimulates angiogenesis directly by stimulating endothelial cells and indirectly by stimulating the production of angiogenic factors (VEGF) by PDL cells. Importantly, the data are consistent with the concept that EMD enhances bidirectional communication between HMVEC and PDL cells during angiogenesis associated with healing.

State of the science on implant dentistry: a workshop developed using an evidence-based approach

PURPOSE

This overview was prepared to describe how an evidence-based approach was used to develop an Academy of Osseointegration (AO) Workshop on the State of the Science on Implant Dentistry (SSID).

MATERIALS AND METHODS

An AO SSID Workshop Planning Committee was appointed in 2001 to follow an evidence-based approach for reviewing published clinical data using strict inclusion and exclusion criteria in order to answer 8 closed-end 4-part clinical questions. A systematic approach was employed to assure coherent data management and analysis. Reviewers, co-reviewers, and a biostatistician were appointed. The workshop agenda was developed to include participants who had the primary responsibility for each of the 8 workshop sections to answer 5 consensus questions for the section's systematic review. The planned outcomes of the SSID Workshop included publication of the 8 consensus reports with their respective systematic reviews in The International Journal of Oral & Maxillofacial Implants (supplemental issue), 2007; the development of clinical guidelines responding to each of the 8 focused questions; and the identification and prioritization of questions or topics requiring further research.

RESULTS

The evidence-based approach was utilized successfully in planning and carrying out the AO SSID Workshop held on August 3-6, 2006, in Oak Brook, Illinois, and the subsequent publication of its proceedings.

DISCUSSION

Although successful in its objectives, the outcome of systematic reviews is only as good as the published data. Significant deficiencies in published implant studies were identified, including, but not limited to, a lack of randomized controlled prospective clinical trials, universal acceptance and publication of defined implant survival and success criteria, and clear questions with well-defined research design.

CONCLUSION

The evidence-based approach can be used to systematically review the literature for a workshop on important questions related to implant dentistry. A major limitation is the lack of common outcome variables between published studies.