The effect of enamel matrix proteins on periodontal regeneration as determined by histological analyses

BACKGROUND

Therapeutic approaches to periodontal regeneration in the past have utilized bone replacement grafts, growth factors, barrier membranes, or combinations of these approaches. More recently, enamel extracellular matrix proteins have been introduced to stimulate periodontal regeneration. One factor thought to have an impact on the outcome of the regenerative process is the initial size of the periodontal defect. This is particularly the case when using proteins to stimulate regeneration, because the concepts of guided tissue regeneration emphasize the need for space maintenance to allow for selected cell repopulation. The goal of this study was to evaluate periodontal regeneration in intrabony defects of various sizes treated with enamel matrix proteins.

METHODS

Periodontal defects ranging in size from 1 to 6 mm were created bilaterally around 3 teeth in the mandibles of baboons. Plaque was allowed to accumulate around ligatures placed into the defects. After 2 months, the ligatures were removed, the teeth were scaled and root planed, and a notch was placed at the base of the defect. On one side of the mandible, neutral ethylene diamine tetracetic acid and enamel matrix proteins were used to treat the defects. The other side served as a control, with neutral ethylene diamine tetracetic acid treatment alone after scaling and root planing. Flaps were sutured and the animals were allowed to heal without oral hygiene procedures. After 5 months, the animals were sacrificed and the teeth were processed for histological evaluation.

RESULTS

Periodontal regeneration occurred in all sizes of the periodontal defects. Qualitatively, new cementum, periodontal ligament with Sharpey's fibers, and new bone tissue were observed. In general, enamel matrix protein treatment resulted in greater tissue formation than controls. In many instances, dramatic tissue formation occurred far coronal to the base of the defects. In addition, horizontal bone fill occurred in defects that were initially 4 or 6 mm wide. The resultant width of the periodontal ligament was similar in all defects regardless of the original defect width. The cementum width was slightly greater in the wider (4 and 6 mm) defects compared to the more narrow (1 and 2 mm) defects. When evaluating the combined 1 and 2 mm defects, the height of new cementum with enamel matrix protein treatment was 45% greater than the control, with 31% greater new bone height versus the control. In the combined wider defects (4 and 6 mm), new tissue height was more similar between enamel matrix protein-treated defects and control defects. The results from the wider defects must be interpreted cautiously, because the interproximal bone heights were resorbed more adjacent to the wider defects during the plaque accumulation period and likely limited the potential for regeneration.

CONCLUSIONS

The treatment of various sized periodontal defects with enamel matrix proteins stimulated substantial periodontal regeneration. In many cases, dramatic amounts of new cementum, Sharpey's fibers, periodontal ligament, and bone tissue were formed far coronal to the notch at the base of the defect, especially considering the width of the original defects. This periodontal regeneration occurred in the absence of exogenous growth factors, bone replacement grafts, barrier membranes, or their combination.

Persistent acute inflammation at the implant-abutment interface

The inflammatory response adjacent to implants has not been well-investigated and may influence peri-implant tissue levels. The purpose of this study was to assess, histomorphometrically, (1) the timing of abutment connection and (2) the influence of a microgap. Three implant designs were placed in the mandibles of dogs. Two-piece implants were placed at the alveolar crest and abutments connected either at initial surgery (non-submerged) or three months later (submerged). The third implant was one-piece. Adjacent interstitial tissues were analyzed. Both two-piece implants resulted in a peak of inflammatory cells approximately 0.50 mm coronal to the microgap and consisted primarily of neutrophilic polymorphonuclear leukocytes. For one-piece implants, no such peak was observed. Also, significantly greater bone loss was observed for both two-piece implants compared with one-piece implants. In summary, the absence of an implant-abutment interface (microgap) at the bone crest was associated with reduced peri-implant inflammatory cell accumulation and minimal bone loss.

Clinical evaluation of anorganic bovine bone xenograft with a bioabsorbable collagen barrier in the treatment of molar furcation defects

The purpose of this study was to compare Bio-Oss (BO), an anorganic bovine bone xenograft, in combination with Bio-Gide (BG), a bioabsorbable collagen barrier, to open-flap debridement (OFD) surgery in human mandibular Class II furcation defects. A total of 31 furcations (18 treatment, 13 control) in 21 patients were treated. There was a statistically significant improvement in most clinical indices for the BO/BG group, with minimal improvement noted for the OFD group. Vertical probing depth reduction of 2.0 mm and horizontal probing depth reduction of 2.2 mm were noted for the BO/BG group, with 0.3 mm and 0.2 mm reductions, respectively, noted for OFD. Hard tissue measurements showed 2.0 mm of vertical furcation bone fill for BO/BG and 0.5 mm for OFD. The BO/BG group had 3.0 mm of horizontal furcation bone fill, and the OFD group had 0.9 mm. The BO/BG group had a defect resolution of 82.7%; 42.5% was noted for the OFD group. There was a statistically significant difference between BO/BG and OFD in all soft and hard tissue measurements with the exception of attachment level, recession, and alveolar crest resorption.

Regenerative materials: an overview

Periodontal reconstructive therapies have demonstrated the ability to reverse the destruction due to periodontitis provided that they are implemented according to their individual indications. By properly evaluating a site, one can employ an evidence-based approach to effectively and predictably treat intrabony defects and furcation involvements. It also should be emphasized that a thorough evaluation of the therapeutic outcome should be continuously performed on all sites in order to determine treatment success and the possible need for further intervention. This is based on the long-term follow-up of cases treated with regenerative therapies, which have shown maintenance of results if the patient had good oral hygiene and was enrolled in a proper maintenance program. With respect to the preceding discussion: 1. The main periodontal reconstructive therapies employed by periodontists are GTR, bone replacement grafts and biologic mediators. 2. It is possible to achieve regeneration when using barriers, autografts, allografts, bovine-derived xenografts and EMDs. 3. Currently, regenerative techniques can be used for the treatment of intrabony defects and furcation involvements given the proper evaluation of each individual site. 4. Various regenerative materials are capable of achieving similar results in intrabony defects and are very predictable when employing evidence-based treatment. 5. A combination of regenerative materials such as barriers and grafts in intrabony defects has not demonstrated any improvement over their use alone. 6. A combination of regenerative materials such as barriers and grafts in mandibular class II furcations has demonstrated improvement over the use of the graft or barrier alone. 7. A combination of regenerative materials such as barriers and grafts in maxillary class II furcations has some limited evidence to support improvement over the use of the graft or barrier alone, but the predictability should not be considered high. 8. A combination of regenerative materials such as barriers and grafts in class III furcations has very limited evidence to support improvement over the use of the graft or barrier alone and should not be considered predictable. 9. Beyond the initial healing phase postsurgically, maintenance and oral hygiene play the largest role in long-term therapeutic success.

Clinical evaluation of wound healing following multiple exposures to enamel matrix protein derivative in the treatment of intrabony periodontal defects

BACKGROUND

Multiple exposures to enamel matrix protein derivative (EMD) during periodontal therapy have been shown to be safe for the patient. The purpose of this study was to clinically determine if an altered course of wound healing would occur after multiple exposures to EMD in the treatment of intrabony defects. A secondary aim was to assess the efficacy of EMD in probing depth reduction and clinical attachment level gain.

METHODS

Thirty-two systemically healthy patients (18 females, 14 males, 33 to 69 years old) who were being treated for moderate to advanced periodontal disease were selected for the study. Surgical procedures involving 2 sites were separated by at least 8 weeks, and wound healing comparisons were made between the first and second procedure. Patients were given a diary card the day of surgery, which consisted of questions concerning the presence and severity of headaches, root hypersensitivity, tooth pain, swelling, and itching. Patients were also examined at postoperative visits to clinically assess wound healing and discuss responses to the questionnaire. Soft tissue measurements were taken the day of surgery and 6 months postoperatively to ascertain probing depth reduction (PD) and gains in clinical attachment levels (CAL).

RESULTS

The results revealed no clinically detectable reaction that could not be attributed to normal postoperative sequelae. There were no differences in reported symptoms between patient gender, first and second procedures, or intrabony and non-intrabony defects. Smokers were found to have a statistically significantly higher incidence of severe symptoms in root hypersensitivity, tooth pain, and swelling compared to non-smokers (n = 21). The mean probing depth reduction was 3.8 +/- 1.5 mm (2 to 9 mm), while the mean clinical attachment level gain was 2.8 +/- 1.7 mm (0 to 8 mm).

CONCLUSIONS

The findings of this study demonstrate that EMD is a clinically safe product to use in the treatment of periodontal defects and that multiple uses do not have a negative impact on periodontal wound healing. In addition, a statistically significant gain in clinical attachment and reduction in probing depth were demonstrated.

Ability of deproteinized cancellous bovine bone to induce new bone formation

BACKGROUND

Preclinical and clinical studies indicate that deproteinized cancellous bovine bone is osteoconductive and may be osteopromotive. Previous studies using commercial preparations failed to demonstrate the presence of protein, implicating bone-mineral composition and 3-dimensional structure as reasons for clinical success; however, these studies did not examine whether osteoinductive factors might be present in close association with the mineral phase.

METHODS

Deproteinized cancellous bovine bone was decalcified and any protein present released by chaotropic solvents using the protocol described for purification of bone morphogenetic proteins (BMPs). Three extracts were obtained and tested for their ability to support osteoinduction in the calf muscle of nude mice.

RESULTS

Protein content averaged 11 microg/g based on absorbance at 280 nm using bovine serum albumin as a standard. All extracts contained material that stained positively with silver stain after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Western blots of these gels indicated the presence of transforming growth factor-beta (TGF-beta) and BMP-2. All 3 extracts were osteoinductive in the nude mouse model when combined with inactive DFDBA, and bone formation was comparable to that induced by active DFDBA. Deproteinized cancellous bovine bone by itself was not osteoinductive in the nude mouse, but in a clinical case, exhibited osteoclastic resorption with adjacent new bone formation.

CONCLUSIONS

The results suggest that small amounts of protein are present in deproteinized cancellous bovine bone in close association with the mineral phase. Some of the extracted material has osteoinductive potential and may contain growth factors. This may explain the osteopromotive ability of deproteinized cancellous bovine bone clinically.

Histologic evaluation of periodontal healing in humans following regenerative therapy with enamel matrix derivative. A 10-case series

BACKGROUND

Enamel matrix derivative (EMD) has been developed as a stimulus of periodontal regeneration. Human histology following its use has not been evaluated on pathologically altered root surfaces.

METHODS

Ten intrabony defects in 8 patients were evaluated at 2 centers. Teeth with advanced adult periodontitis that were treatment planned for extraction were treated with sulcular incisions; full-thickness flap reflection; debridement of granulomatous tissue from the defect; placement of a notch in the root at the apical extent of calculus; mechanical root planing; conditioning with citric acid; application of EMD; wound closure with sutures; and placement of a periodontal dressing. Biweekly to monthly recalls were made until removal of small block section biopsies at about 6 months. The biopsies were fixed, decalcified, step-serial sectioned at 6 microns to 8 microns, and stained with hematoxylin and eosin or Masson's trichrome.

RESULTS

Histologic evaluation of the region coronal to the base of the calculus notch showed evidence of regeneration (new cementum, new bone, and new periodontal ligament) in 3 specimens, new attachment (connective tissue attachment/adhesion only) in 3 specimens, and a long junctional epithelium in 4 specimens. No evidence of root resorption, ankylosis, or untoward inflammation was seen.

CONCLUSIONS

The results of this study fulfill the proof of principle that use of EMD can result in periodontal regeneration on previously diseased root surfaces in humans, but on an inconsistent basis.

Human histologic evaluation of a bovine-derived bone xenograft in the treatment of periodontal osseous defects

This study evaluated a bovine-derived bone xenograft (Bio-Oss) in the treatment of human periodontal osseous defects. Four patients with at least one tooth that had been recommended for extraction because of interproximal advanced periodontal disease volunteered to participate. The surgical procedure consisted of flap reflection, soft tissue debridement, placing a notch in calculus as a histologic reference point, root planing, placement of the bovine-derived xenograft and a bioresorbable physical barrier, and flap closure. Patients were seen every 2 weeks for plaque control and any necessary adjunctive treatment. At 4 to 6 months postsurgery, 6 teeth, along with the adjacent graft site, were removed en bloc. Histologic observations demonstrated new bone, new cementum, and new periodontal ligament coronal to the reference notch in 3 of the 4 specimens. This study indicates that periodontal regeneration is possible following grafting with a bovine-derived xenograft.

The effect of locally delivered controlled-release doxycycline or scaling and root planing on periodontal maintenance patients over 9 months

BACKGROUND

This research report evaluates clinical changes resulting from local delivery of doxycycline hyclate (DH) or traditional scaling and root planing (SRP) in a group of patients undergoing supportive periodontal therapy (SPT).

METHODS

In all, 141 patients received either DH (67) or SRP (74) treatment in sites > or =5 mm on one-half of their dentition at baseline and month 4.

RESULTS

Clinical results were determined at month 9. Baseline mean probing depth recordings were similar between the two groups (DH = 5.9 mm; SRP = 5.9 mm). Mean month 9 results showed similar clinical results for attachment level gain (DH 0.7 mm; SRP 0.8 mm) and probing depth reduction (DH 1.3 mm; SRP 1.1 mm). Percentage of sites showing > or =2 mm attachment level gain at month 9 was 24.7% in the DH group and 21.2% in the SRP group. Thirty-nine percent (39%) of DH sites and 38% of SRP sites showed > or =2 mm probing depth reduction. When treated sides of the dentition were compared to untreated sides, DH showed a difference in disease activity (> or =2 mm attachment loss) from 19.3% (untreated) to 7.2% (treated); and SRP from 14.3% (untreated) to 8.1% (treated).

CONCLUSIONS

Results show that both DH without concomitant mechanical instrumentation and SRP were equally effective as SPT in this patient group over the 9-month study period.

The Accuracy of Radiographic Methods in Assessing the Outcome of Periodontal Regenerative Therapy

BACKGROUND

The study of regenerative therapy in the periodontal intrabony defect has relied upon surgical re-entry as the gold standard of outcome assessment. The search for a non-invasive method has led to the application of various radiographic techniques in evaluating post-treatment bone fill.

METHODS

The purpose of this study was to determine the ability of 2 forms of radiographic analyses (linear measurement and computer assisted densitometric image analysis, CADIA) to assess postsurgical bone fill as measured at a re-entry procedure. A method that incorporates linear measurements and CADIA (linear-CADIA) was developed and tested as well. Forty-five intrabony defects in 15 patients were treated with open flap debridement, demineralized freeze-dried bone allograft (DFDBA), or a combination of DFDBA and tetracycline. Standardized radiographs were obtained at baseline and at 1-year postsurgery.

RESULTS

A 12-month surgical re-entry provided clinical measurements for post-treatment bone fill. All radiographs were digitally scanned and analyzed on a computer. Fifty-three percent of the defects were excluded from the study due to poor standardization or poor defect quality. Forty percent of all pairs of radiographs were judged to have poor standardization. In the first analysis, standardized images were subtracted and quantitatively analyzed utilizing CADIA. It was found that CADIA had the highest correlation with clinical bone fill when a region of interest (ROI) was examined in the middle portion of the defect. This quantitative evaluation provided very little clinically relevant information regarding actual bone fill. For the second analysis, pre- and post-treatment linear radiographic measurements were obtained. In only 43% of the sites, did linear radiographic measurements determine post-treatment bone fill within 1.0 mm of the clinical measurements. Overall, linear measurements underestimated bone fill by 0.96 mm (+/-1.2). These differences were statistically significant (paired Student t-test, P = 0.0023). A method, which incorporates the use of both CADIA and linear radiographic measurements (linear-CADIA), was tested. The linear-CADIA method underestimated bone fill by 0.26 mm (+/-1.4), but these differences were not statistically significant (paired Student t-test, P = 0.41).

CONCLUSION

Linear radiographic measurements significantly underestimate post-treatment bone fill when compared to re-entry data. The linear-CADIA method provided the highest level of accuracy of the 3 methods tested. This study also emphasizes the importance of developing a consistent method of radiographic standardization.

Clinical evaluation of Bio-Oss: a bovine-derived xenograft for the treatment of periodontal osseous defects in humans

The purpose of this study was to compare the bovine derived xenograft (BDX) Bio-Oss to demineralized freeze dried bone allograft (DFDBA) in human intrabony defects. 17 healthy patients with no systemic disease with moderate-severe periodontitis (7 males, 10 females; aged 34-67), were treated. Surgically, defects were included only if the intraosseous defect depth was >3.0 mm. Final selection included 30 defects. The sites were randomly assigned treatment with DFDBA or BDX. Soft tissue and osseous defect measurements were taken the day of surgery and 6 months post-operatively at re-entry. Average baseline PD, CAL, and surgical defect depth for the DFDBA group were not statistically different from the BDX group. No adverse healing response occurred. The results showed a statistically significant improvement in PD and AL for both materials at 6 months in 26 defects (4 defects did not respond to therapy). Soft tissue measurements for the DFDBA group included PD reduction of 2.0+/-1.3 mm, and AL gain of 2.6+/-1.6 mm, while the BDX group showed a PD reduction of 3.0+/-1.7 mm, and AL gain of 3.6+/-1.8 mm. Osseous measurements showed bone fill of 2.4 mm (46.8%) for the DFDBA group and 3.0 mm (55.8%) for the BDX group. Defect resolution was 59.4% for the DFDBA group and 77.6% for the BDX group. Statistical analysis revealed there was no statistical difference between the 2 materials in all measurements.

Treatment of a large periapical lesion with loss of labial cortical plate using GTR: a case report

Following endodontic treatment, a large periapical lesion (9.0 mm x 9.0 mm) at a maxillary central incisor was treated with demineralized freeze-dried bone allograft (DFDBA) using the principles of guided tissue regeneration. The physical barrier was removed 6 months postsurgical. The cortical alveolar plate was observed to be completely reconstructed. Histologic evaluation demonstrated lamellar bone surrounding DFDBA particles. Radiographic follow-up 1 year posttreatment demonstrated complete resolution of the periapical radiolucency.

Two multi-center studies evaluating locally delivered doxycycline hyclate, placebo control, oral hygiene, and scaling and root planing in the treatment of periodontitis

BACKGROUND

The clinical efficacy and safety of doxycycline hyclate (8.5% w/w) delivered subgingivally in a biodegradable polymer (DH) was compared to placebo control (VC), oral hygiene (OH), and scaling and root planing (SRP) in 2 multi-center studies.

METHODS

Each study entered 411 patients who demonstrated moderate to severe periodontitis. Patients had 2 or more quadrants each with a minimum of 4 qualifying pockets > or =5 mm that bled on probing. At least 2 of the pockets were > or =7 mm. Treatment with DH, VC, OH, or SRP was provided at baseline and again at month 4. Clinical parameters were recorded monthly.

RESULTS

DH and SRP resulted in nearly identical clinical changes over time in both studies. Mean 9 month clinical attachment level gain (ALG) was 0.8 mm for the DH group and 0.7 mm for the SRP group in Study 1, and 0.8 mm (DH) and 0.9 mm (SRP) in Study 2. Mean probing depth (PD) reduction was 1.1 mm for the DH group and 0.9 mm for the SRP group in Study 1 and 1.3 mm for both groups in Study 2. Frequency distributions showed an ALG > or =2 mm in 29% of DH sites versus 27% of SRP sites in Study 1 and 31% of DH sites versus 34% of SRP sites in Study 2. PD reductions > or =2 mm were seen in 32% of DH sites versus 31% of SRP sites in Study 1 and 41% of DH sites versus 43% of SRP sites in Study 2. Comparisons between DH, VC, and OH treatment groups showed DH treatment to be statistically superior to VC and OH. Safety data demonstrated a benign safety profile with use of the DH product.

CONCLUSIONS

Results of this trial demonstrate that treatment of periodontitis with subgingivally delivered doxycycline in a biodegradable polymer is equally effective as scaling and root planing and superior in effect to placebo control and oral hygiene in reducing the clinical signs of adult periodontitis over a 9-month period. This represents positive changes resulting from the use of subgingivally applied doxycycline as scaling and root planing was not limited regarding time of the procedure or use of local anesthesia.

Comparison of bioactive glass to demineralized freeze-dried bone allograft in the treatment of intrabony defects around implants in the canine mandible

BACKGROUND

The purpose of this study was to evaluate and compare the healing of different bone grafting materials adjacent to titanium plasma-sprayed (TPS) endosseous dental implants.

METHODS

Implant osteotomy sites were prepared and standardized 3-walled intrabony defects (3 mm x 5 mm x 5 mm) were created at the mesial of each implant site. Thirty-two TPS implants were placed in edentulous mandibular ridges of the 4 dogs. Periodontal dressings were placed in the defect sites so as to create a defect simulating bone loss around an implant. After 3 months, the periodontal dressing was removed, the defect sites debrided and evaluated for size, and intramarrow penetration performed. The graft materials tested were 1) canine demineralized freeze-dried bone allograft (cDFDBA); 2) bioactive glass granules of a broad size range 90 to 710 microns (BRG); and 3) bioactive glass granules of narrow size range 300 to 355 microns (NRG). One site on each side of the mandible was not filled and served as a control. Dogs were sacrificed 4 months after graft placement.

RESULTS

Histologically, differences in percent bone-to-implant contact in the defect area were observed between the treatment groups. cDFDBA>control=BRG=NRG with statistical significance found between cDFDBA and control (P = 0.0379), but no statistically significant difference between control or either bioactive glass material. When comparing percent bone height fill of the defect in the grafted area, cDFDBA (65.7%) was significantly better than the control (48.9%; P < or = 0.05) with no statistically significant difference between control, broad range bioactive glass (57.3%) and narrow range bioactive glass (56.6%). When total bone area was measured, the percentage of new bone in the grafted area was cDFDBA (42.1%), broad range glass (33.1%) and narrow range glass (22.6%) with significance found between cDFDBA and NRG (P = 0.0102). The content of residual graft particles in soft tissue was significant (P = 0.0304) between cDFDBA (1.4%) and NRG (11.4%) with no significant difference between graft material for residual particle content in bone tissue.

CONCLUSIONS

The results of this study indicate that percent bone-to-implant contact and percent bone height fill in an intrabony defect around titanium plasma-sprayed implants are statistically significantly higher with the use of DFDBA when compared to bioactive glass material.

Evaluation of 2 novel approaches for assessing the ability of demineralized freeze-dried bone allograft to induce new bone formation

BACKGROUND

Because of the wide variation in the ability of human demineralized freeze-dried bone allograft (DFDBA) to reproducibly induce new bone formation, there is a need for a reliable measure of bone induction activity. In this study we examined an immature osteoprogenitor cell line for its potential utility in measuring the activity of DFDBA in vitro.

METHODS

We characterized the response of 2T9 cells, an immature osteoprogenitor cell line derived from the calvariae of transgenic mice containing the SV40 T-antigen driven by the mouse bone morphogenetic protein (BMP)-2 promoter, to recombinant human BMP-2 by measuring alkaline phosphatase specific activity, osteocalcin production, and matrix mineralization. Responses were compared to those obtained with 1,25-(OH)2D3. In addition, 2T9 cells were cultured with active or inactive human DFDBA in the presence or absence of BMP-2. We also tested the hypothesis that radio-opacity of tissue following implantation of DFDBA in vivo correlates with the ability of human DFDBA to induce new bone. DFDBA from 9 different donors, stratified by age, were implanted subcutaneously in the thorax of 18 nude (nu/nu) mice. Tissue was harvested at 36 days postoperatively and examined histologically and biochemically for calcium and phosphorus uptake.

RESULTS

2T9 cells exhibited a dose- and time-dependent response to soluble BMP-2. Proliferation was decreased and alkaline phosphatase activity, osteocalcin production, and mineralized nodule formation were increased. The effects were dose- and time-dependent. Peak effects on alkaline phosphatase and osteocalcin were noted on day 8, whereas mineral deposition did not begin to occur until day 12. 1,25-(OH)2D3 did not regulate these effects unless used with BMP-2. When the cells were exposed to active or inactive DFDBA in the presence or absence of BMP-2, no effect on 2T9 cell differentiation was observed. This indicated that DFDBA released no soluble factors with bone inductive ability and that if any active factors were adsorbed to the DFDBA, they were inactivated. When DFDBA was implanted subcutaneously in the thorax of nude mice, there was no histologic evidence of new bone formation. However, there was a donor age-dependent decrease in Ca and P uptake of the implanted tissue, reflecting a donor age-dependent decrease in remineralization of DFDBA.

CONCLUSIONS

These data indicate that cell culture assays like the one used in this study may not be appropriate indicators of bone induction ability by DFDBA since soluble factors may not be responsible for bone induction in vivo. Nonetheless, in vitro assays are still needed. While Ca and P uptake by DFDBA-implanted tissue in the present study correlated with the age-dependent decrease in bone induction at intramuscular sites in a previously reported study, these data show that early x-rays may actually detect remineralization and not new bone formation. Thus, assessment of bone induction ability may still depend on histologic analysis of animal models.

Enamel matrix derivative for periodontal reconstructive surgery: technique and clinical and histologic case report

This paper describes a step-by-step technique for the application of Emdogain, a new enamel matrix derivative (EMD) graft material, for periodontal reconstructive surgery. A case report is presented with a 1-year follow-up. The rationale for use and advantages and disadvantages of EMD are discussed. An additional human histologic case report demonstrates that the formation of new bone, cementum, and periodontal ligament is possible following the use of EMD.

Addition of human recombinant bone morphogenetic protein-2 to inactive commercial human demineralized freeze-dried bone allograft makes an effective composite bone inductive implant material

COMMERCIAL PREPARATIONS OF HUMAN DEMINERALIZED freeze-dried bone allograft (DFDBA) vary in their ability to induce new bone formation. This study tested the hypothesis that inactive DFDBA can be used as an effective carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2). Two batches of active DFDBA were used as controls. Two batches of DFDBA, previously shown to be inactive, were treated with vehicle or with 5 or 20 microg rhBMP-2 and implanted into the calf muscle of male Nu/Nu (nude) mice. Each mouse received one implant in each hind limb, both of which were of the same formulation, resulting in 8 groups of 4 mice per group: active DFDBA batch A, active DFDBA batch B, inactive DFDBA batch A, inactive DFDBA batch B, inactive DFDBA batch A plus 5 microg rhBMP-2, inactive DFDBA batch A plus 20 microg rhBMP-2, inactive DFDBA batch B plus 5 microg rhBMP-2, and inactive DFDBA batch B plus 20 microg rhBMP-2. After 56 days, the implants were removed and histologically examined. A semiquantitative bone induction index was calculated based on the amount of new bone covering each histological section. Histomorphometry was also used to evaluate the area of new bone formed and the area of residual implant material. The results showed that active DFDBA induces new bone formation, whereas inactive DFDBA does not. Addition of rhBMP-2 to inactive DFDBA results in new bone formation with a bone induction index comparable to that of active DFDBA. Histomorphometric analysis, however, revealed that the rhBMP-2-containing implants caused a dose-dependent increase in new bone area that exceeded that induced by active DFDBA. At the highest concentration of rhBMP-2, bone formation was exuberant. rhBMP-2 also caused the resorption of residual implant material to levels comparable to that seen in sites treated with active DFDBA, suggesting that this growth factor may regulate resorptive cells either directly or indirectly. This study shows that addition of rhBMP-2 to inactive DFDBA provides reproducible, consistent bone induction, and suggests that inactive commercial preparations may contain inadequate amounts of BMP to cause bone induction compared to active preparations.

Clinical evaluation of bioactive glass in the treatment of periodontal osseous defects in humans

The purpose of this study was to compare the use of bioactive glass to demineralized freeze-dried bone allograft (DFDBA) in the treatment of human periodontal osseous defects. Fifteen systemically healthy patients (6 males and 9 females, aged 30 to 63) with moderate to advanced adult periodontitis were selected for the study. All patients underwent initial therapy, which included scaling and root planing, oral hygiene instruction, and an occlusal adjustment when indicated, followed by re-evaluation 4 to 6 weeks later. Paired osseous defects in each subject were randomly selected to receive grafts of bioactive glass or DFDBA. Both soft and hard tissue measurements were taken the day of surgery (baseline) and at the 6-month re-entry surgery. The clinical examiner was calibrated and blinded to the surgical procedures, while the surgeon was masked to the clinical measurements. Statistical analysis was performed by using the paired Student's t test. The results indicated that probing depths were reduced by 3.07 +/- 0.80 mm with the bioactive glass and 2.60 +/- 1.40 mm with DFDBA. Sites grafted with bioactive glass resulted in 2.27 +/- 0.88 mm attachment level gain, while sites grafted with DFDBA had a 1.93 +/- 1.33 mm gain in attachment. Bioactive glass sites displayed 0.53 +/- 0.64 mm of crestal resorption and 2.73 mm bone fill. DFDBA-grafted sites experienced 0.80 +/- 0.56 mm of crestal resorption and 2.80 mm defect fill. The use of bioactive glass resulted in 61.8% bone fill and 73.33% defect resolution. DFDBA-grafted defects showed similar results, with 62.5% bone fill and 80.87% defect resolution. Both treatments provided soft and hard tissue improvements when compared to baseline (P < or = 0.0001). No statistical difference was found when comparing bioactive glass to DFDBA; however, studies with larger sample sizes may reveal true differences between the materials. This study suggests that bioactive glass is capable of producing results in the short term (6 months) similar to that of DFDBA when used in moderate to deep intrabony periodontal defects.

Evaluation of a bioabsorbable physical barrier for guided bone regeneration. Part II. Material and a bone replacement graft

Part I of the evaluation of a prototype bioabsorbable physical barrier composed of a copolymer of lactide and glycolide for treatment of bone defects in the guided bone regeneration procedure indicated that the prototype bioabsorbable physical barrier did not possess sufficient spacemaking characteristics to prevent collapse of the barrier into the defect or against the threads of the titanium implants. The purpose of Part II was to evaluate this bioabsorbable physical barrier in combination with a supporting material to prevent barrier collapse. Posterior mandibular teeth in three dogs were extracted and allowed to heal for 3 months. This produced localized alveolar ridge defects with a narrow buccolingual width. Six titanium threaded implants were placed in the right and left mandibles of each dog so that nonspacemaking dehiscencetype defects were produced. Two defects in each animal were randomly treated with the prototype bioabsorbable physical barrier and decalcified freeze-dried bone allograft; two defects were treated with a nonbioabsorbable expanded polytetrafluoroethylene barrier with decalcified freeze-dried bone allograft; and one defect each was treated with prototype bioabsorbable physical barrier alone or by flap access with no barrier or bone replacement graft. The results demonstrated that both the bioabsorbable and the nonbioabsorbable barrier combined with decalcified freeze-dried bone allograft produce comparable amounts of new bone with percent bone-to-implant contact, height, width, and area. Defects treated with the prototype bioabsorbable physical barrier alone or no barrier demonstrated unfavorable results. It is suggested that a bone replacement graft is indicated when treating defects with a nonspacemaking morphology.

Ability of commercial demineralized freeze-dried bone allograft to induce new bone formation is dependent on donor age but not gender

Demineralized freeze-dried bone allografts (DFDBA) have been used extensively in periodontal therapy. DFDBA is used because it contains bone morphogenetic protein (BMP), which induces new bone formation during the healing process. Most commercial bone banks do not verify the presence or activity of BMP in DFDBA nor the ability of DFDBA to induce new bone. Recently, we showed that different bone bank preparations of DFDBA, even from the same bank, varied considerably in their ability to induce new bone, suggesting inherent differences in the quality of the material. Therefore, we examined whether donor age or gender contributed to the variability seen with these preparations. Twenty-seven batches of DFDBA from different donors were donated by one bone bank which had been shown previously to supply DFDBA that was consistently able to induce new bone formation. Each batch was implanted bilaterally in the thigh muscle of nude mice. After 56 days, the implants were excised and examined by light microscopy and histomorphometry. Seventy percent of the preparations tested induced new bone formation. Most of these preparations produced ossicles containing cortical bone surrounding bone marrow-like tissue. The ability to induce bone appears to be age-dependent, with DFDBA from older donors being less likely to have strong bone-inducing activity. By contrast, no difference in ability to induce new bone was noticed between male or female donors. The results of this study confirm that commercial preparations of DFDBA differ in their ability to induce new bone formation. In fact, some of the batches had no activity at all. The ability of DFDBA to induce new bone formation is suggested to be age-dependent, but not gender-dependent by our study. These results indicate that commercial bone banks need to verify the ability of DFDBA to induce new bone formation and should reconsider the advisability of using bone from older donors.

Evaluation of a bioabsorbable physical barrier for guided bone regeneration. Part I. Material alone

This study evaluates a prototype bioabsorbable physical barrier material for guided bone regeneration. Nonspacemaking dehiscence-type defects were surgically created in the right and left mandibles of six adult dogs. Each animal received six root-form threaded titanium implants. The osseous defects were randomized to receive treatment by either the prototype bioabsorbable barrier composed of a copolymer of lactide and glycolide, an expanded polytetrafluoroethylene nonresorbable barrier, or no barrier (control), Clinical and histologic results after 3.5 months of wound healing indicated that exposed threads were covered when treated with the expanded polytetrafluoroethylene barrier. Minimal thread coverage was evident with the bioabsorbable barrier and the control.

Implants in regenerated bone: long-term survival

This retrospective multicenter study analyzed 526 implants placed and loaded in regenerated bone. Both autogenous and allogeneic bone grafts were used in combination with a barrier membrane to reconstruct bone using either a simultaneous or staged approach. Implants were followed from 6 to more than 74 months postloading. Eight of the implants were lost, for a success rate of 97.5%. The type of graft material did not affect the clinical success of the implants, nor did the use of submerged versus nonsubmerged implants or a staged versus a simultaneous approach. In conclusion, regenerated bone reacted to implant placement in a manner that was clinically similar to native bone.

Clinical efficacy of the Nd:YAG laser for combination periodontitis therapy

Recent results of a limited clinical trial suggest that mechanical root scaling and root planing therapy alone may not be the most effective mode of treatment for patients affected by moderate to severe adult periodontitis. However, scaling and planing combined with laser therapy utilizing a low-powered pulsed Nd:YAG laser have been shown to be successful in the elimination of the bacteria commonly associated with the development of this oral condition. The double-blind, split mouth design study involved 10 human subjects randomly assigned to one of three treatments: 1) scaling and root planing alone, 2) dental laser plus scaling and root planing, and 3) control only. This article presents the clinical results of the trial, which suggest that laser therapy is a viable adjunct to local, nonsurgical therapy such as scaling and planing.

A clinical evaluation of a bioresorbable barrier with and without decalcified freeze-dried bone allograft in the treatment of molar furcations

This study evaluated a bioresorbable barrier with and without decalcified freeze-dried bone allograft (DFDBA) in the treatment of human molar furcations. 14 subjects with paired class II mandibular molar furcation defects participated in the study (8 male and 6 female). The class-II furcation defects were randomly treated with either the resorbable barrier alone or resorbable barrier in combination with decalcified freeze-dried bone allograft (DFDBA). Gingival recession, probing depth, clinical attachment, and bone fill were measured 6 months post-treatment measurements were repeated and each site was surgically re-entered. When the resorbable barrier alone was compared to resorbable barrier in combination with DFDBA, probing depth reduction was significantly (p < 0.01) in favor of the combination therapy. Vertical bone gain was significant with the combination treatment demonstrating more bone fill (p < 0.02). Smoking was also a variable examined in this study. When compared to smokers, non-smokers for both treatment groups revealed greater probing depth reduction, vertical bone gain, and horizontal bone gain. Within the non-smoking group, probing depth reduction was also significantly higher for the resorbable barrier and DFDBA group than the resorbable alone group (p < 0.02). These results illustrate that the probing depth reduction is better in the non-smoker and the best in the non-smoker with the combination therapy of resorbable barrier and DFDBA than with resorbable barrier alone.

Ability of commercial demineralized freeze-dried bone allograft to induce new bone formation

Demineralized freeze-dried bone allograft (DFDBA) has been used extensively in periodontal therapy. The rationale for use of DFDBA includes the fact that proteins capable of inducing new bone; i.e., bone morphogenetic proteins, can be isolated from bone grafts. Commercial bone banks have provided DFDBA to the dental practitioner for many years; however, these organizations have not verified the osteoinductive capacity of their DFDBA preparations. The aim of this study was to determine the ability of commercial DFDBA preparations to induce new bone formation. DFDBA with particle sizes ranging from 200 to 500 microns was received from six bone banks using various bone production methods. Different lots of DFDBA from the same tissue bank were sometimes available. A total of 14 lots were examined. The surface area of bone particles in each sample was measured morphometrically and the pH of a solution containing the particles after suspension in distilled water determined. Samples from each DFDBA lot were implanted intramuscularly (10 mg) or subcutaneously (20 mg) into three different animals and tissue biopsies harvested after 4 weeks. One sample from each tissue bank was implanted and harvested after 8 weeks. At harvest, each area where DFDBA had been implanted was excised and examined by light microscopy. The ability of DFDBA to produce new bone was evaluated and the amount of residual bone particles measured. The results show that bone particles from all tissue banks had a variety of shapes and sizes, both before implantation and after 1 or 2 months of implantation. The pH of particle suspensions also varied between batches, as well as between tissue banks. None of the DFDBA induced new bone formation when implanted subcutaneously. Intramuscular implants from three banks induced new bone formation after 1 and 2 months. DFDBA from two banks caused new bone formation only after 2 months. However, DFDBA from one bank did not induce new bone at all. Particle size before implantation correlated with particle size after implantation. However, particle size did not correlate with ability to induce bone. The results show that commercial DFDBA differs in both size and ability to induce new bone formation, but that the two are not related. The study also indicates that wide variation in commercial bone bank preparations of DFDBA exist and that ability to induce new bone formation also varies widely. Furthermore, the results suggest that methods or assays for evaluating the ability of DFDBA to induce new bone should be developed and standardized.

A clinical evaluation of demineralized freeze-dried bone allograft in combination with tetracycline in the treatment of periodontal osseous defects

The purpose was to evaluate the use of demineralized freeze-dried bone allograft reconstituted with 50 mg/ml tetracycline hydrochloride in the treatment of intrabony periodontal defects. Fifteen systemically healthy patients (12 females, 3 males; aged 35 to 61) with moderate-advanced periodontitis were treated. Patients had 3 osseous defects with probing depths (PD) > 5 mm after initial therapy. Each site in each subject was randomly assigned to one of the following groups: 1) demineralized freeze-dried bone allograft reconstituted with 50 mg/ml tetracycline (DFDBA + TCN); 2) demineralized freeze-dried bone allograft alone (DFDBA); or 3) debridement only (D). Clinical measurements were taken the day of surgery, 6 months, and 1 year. Standardized radiographs were taken at baseline and 1 year and were evaluated by computer assisted densitometric image analysis (CADIA). Clinical measurements included gingival recession, PD, clinical attachment level, and mobility. Osseous defect measurements were taken at baseline and at the 1 year reentry. No adverse healing responses occurred. The results showed that all patients had a statistically significant improvement in probing depth and attachment level at 1 year. Osseous measurements showed bone fill of 2.27 mm (51.6%) for the DFDBA + TCN group, 2.20 mm (52.4%) for the DFDBA group, and 1.27 mm (32.8%) for the D group. Defect resolution was 77.3% for the DFDBA + TCN group, 77.9% for the DFDBA group, and 63.8% for the D group. The mean CADIA values were 5.04 for the DFDBA + TCN group, 6.79 for the DFDBA group and 2.78 for the D group. The CADIA values did not correlate with the clinical parameters. Although the grafted groups showed greater bone fill and defect resolution, there was no statistically significant difference in any of the clinical parameters between the treatment groups. This study suggests that there is no significant benefit from reconstituting the allograft with 50 mg/ml of tetracycline hydrochloride.

Clinical evaluation of demineralized-unicortical-ilium-strips for guided tissue regeneration

This study compared demineralized-unicortical-ilium-strips (DUIS) and an expanded polytetrafluoroethylene (ePTFE) physical barrier in combination with decalcified freeze-dried bone allograft (DFDBA) for treatment of Class II mandibular furcations. Twenty patients with adult periodontitis and at least 2 furcation invasions participated in this study. Probing depth (PD), clinical attachment level (CAL), and bone fill were measured at 6 and 12 months. Standardized radiographs were analyzed using computer assisted densitometric image analysis (CADIA). Fifteen of 20 patients completed the 12-month evaluation. At 6 months both control and test groups showed significant reductions in PD from baseline (P < 0.01). PD reduction for the ePTFE + DFDBA sites was 2.13 mm +/- 1.25, and the DUIS + DFDBA, 1.77 mm +/- 1.21. CAL at 6 months was sustained to 12 months when the net gains in CAL for ePTFE + DFDBA being 1.30 mm +/- 1.45 (P < 0.01) and for DUIS + DFDBA sites 1.13 mm +/- 1.68 (P < 0.02). The horizontal furcation PD decreased 2.87 mm +/- 1.68 (P < 0.01) in the ePTFE + DFDBA and 1.70 mm +/- 1.69 (P < 0.01) for DUIS + DFDBA sites over 12 months. The evaluation of the hard tissue response at the 12-month re-entry demonstrated a bone fill of 2.37 mm (75%) +/- 2.04 (P < 0.01) with ePTFE + DFDBA and 1.83 mm (79%) +/- 1.57 (P < 0.01) with DUIS + DFDBA. DUIS material and ePTFE showed significant improvements in clinical parameters and neither material proved to be significantly better. However, a larger sample size may have permitted us to demonstrate statistically significant differences between the materials. The positive results from the utilization of DUIS for GTR and the advantage of its bioresorbability warrant further investigation. The study found limitations in the use of CADIA for evaluation of guided tissue regeneration in furcations.

Evaluation of guided tissue regeneration in interproximal defects. (II). Membrane and bone versus membrane alone

This study clinically evaluates the use of expanded polytetrafluoroethylene (ePTFE) membranes with or without the addition of decalcified freezedried bone allograft (DFDBA) in the treatment of interproximal intraosseous defects. 25 patients (26 paired defects) diagnosed with advanced periodontitis and having at least 2 bilateral interproximal probing depths of > or = 6 mm participated in the study. After the hygiene phase, measurements were made to determine soft tissue recession, pocket depth, and clinical attachment levels. Defects from each pair were randomly treated with either ePTFE alone (control), or ePTFE+DFDBA (experimental). Measurements were made during the surgery to determine crestal resorption, defect resolution and defect fill. Membranes were removed at 4 to 6 weeks. At 6 months, the soft and hard tissue measurements (surgical reentry) were repeated. Both groups showed statistically significant improvement when compared to baseline (p < 0.001), but no difference was determined between groups. Control sites showed a 50% bone fill and experimental sites had 54% bone fill. The defect resolution changes were also similar between control and experimental groups, respectively (80%, 74%). For this short-term study, it was concluded that either technique was beneficial for the treatment of intraosseous defects. Other studies are needed to assess the long-term stability of the improvements rendered by these treatments.

Bone allografts in periodontal therapy

Bone allografts as used in dentistry have a 20-year history of safety and efficacy. Case reports and controlled clinical trials have shown the potential of both mineralized and decalcified cortical freeze-dried bone allograft to reconstruct the bone defects caused by periodontitis. Histomorphometric analysis of human biopsies following grafts of decalcified freeze-dried bone allograft have shown the ability of decalcified freeze-dried bone allograft to promote regeneration of new bone, cementum, and periodontal ligament on a tooth root surface previously exposed to bacterial plaque. The addition of mineralized freeze-dried bone allograft and decalcified freeze-dried bone allograft to the guided tissue and guided bone regeneration procedures have significantly enhanced results, especially in large osseous lesions.

Treatment of the failing implant: case reports

Three case reports of treatment of the failing implant are presented. The implants were immobile but had lost a significant amount of osseous support. The cause of failure was determined to be a combination of bacterial and occlusal traumatogenic insult. The defects were debrided and the implant surface was detoxified with tetracycline. Decalcified freeze-dried bone allograft was implanted in the osseous defects and covered with expanded polytetrafluoroethylene material in accordance with principles of guided tissue regeneration. The barrier membrane was removed 6 to 8 weeks after placement. Eight months to 1 year posttreatment, all sites demonstrated a substantial reduction in probing depth, a gain in clinical attachment, and bone fill of the defects adjacent to the implant.

Donor selection, testing, and inactivation of the HIV virus in freeze-dried bone allografts

This article is a comprehensive review of the safety of currently used freeze-dried bone allografts. The development of exclusionary criteria for donor procurement is discussed along with the steps taken in processing. The processing includes harvesting in a sterile manner, repeated washings, immersion in ethanol, freezing in liquid nitrogen, freeze-drying, demineralization, and vacuum sealing. The statistical data of laboratory testing for the HIV virus is presented, and the advantages and disadvantages of the ELISA and the PCR tests are outlined. There are four known cases of HIV transmission from bone allograft donors, and the circumstances of these four transmissions are discussed. An overview of hepatitis and other infectious diseases in bone allografts completes the review. The learning objective of this article is to update reader knowledge of measures taken to ensure safety in the utilization of DFDB allografts.

The functional interaction of EGF and PDGF with bradykinin in the proliferation of human gingival fibroblasts

Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF)-BB are both involved in periodontal wound healing. Each of these growth factors exerts a positive proliferative effect on cells of the periodontium in vitro. However, in vivo the peptide bradykinin is one of a complex array of mediators present in addition to these growth factors. The purposes of this investigation were to: 1) evaluate bradykinin interactions with EGF and PDGF-BB altering cell proliferation in cultured human gingival fibroblasts (HGF), periodontal ligament cells (HPDL), and cells derived from alveolar bone (HOB); and 2) determine at the signal transduction level the mechanism of interaction between EGF and bradykinin in HGF. EGF and PDGF-BB stimulated DNA synthesis in a concentration-dependent manner, as measured by [3H] thymidine incorporation. Bradykinin alone did not alter significantly based DNA synthesis values; however, bradykinin in combination with EGF reduced DNA synthesis to nearly basal levels and bradykinin in combination with PDGF reduced the DNA synthesis over 50%. Examination of the interactions between bradykinin and EGF signal transduction pathways revealed that PGE2 release was increased in the presence of bradykinin and EGF (167 +/- 33% to 317 +/- 29%). The bradykinin-stimulated PGE2 release was completely abolished by indomethacin. Indomethacin also was found to block the bradykinin inhibition of EGF-induced DNA synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Guided bone regeneration of bone defects associated with implants: an evidence-based outcome assessment

Guided bone regeneration is a new technique that evolved following the guided tissue regeneration procedure for regeneration of lost periodontium. The objective of guided bone regeneration is to promote bone formation in osseous deformities either before or in conjunction with endosseous implant placement. Osseous defects consist mainly of extraction sites, dehiscences or fenestrations, and localized ridge deformities. In addition, bone defects may either provide natural spacemaking or be nonspacemaking. A plethora of publications indicate that the guided bone regeneration technique can be used successfully in all types of defects. Nonspacemaking defects usually require bone graft materials to assist in space maintenance and enhance bone formation. Fixation pins are also used, either with or without graft materials, in this regard. The scientific literature on guided bone regeneration was reviewed by a task force to determine techniques proven to increase predictability relative to successful patient outcomes and to develop specific evidence based diagnostic and treatment decision trees.

Guided bone regeneration in the treatment of a large periapical lesion: a case report

A large (19 mm x 24 mm) periapical lesion associated with tooth #10, perforating both the labial and palatal cortical plates, was treated with decalcified freeze-dried bone allograft and guided bone regeneration. The membranes were removed after a seven-month healing period. Complete osseous reconstruction of the cortical plates was noted. Biopsies demonstrated healing with mature bone and hemopoietic marrow. Few particles of decalcified freeze-dried bone could be observed. Graft particles that remained were surrounded by new bone. The learning objective of this article is to present the regeneration procedure utilized along with the histologic biopsy results to the clinician.

Clinical evaluation of guided tissue regeneration in the treatment of grade II molar furcation invasions

This paper evaluates the use of guided tissue regeneration for treating 19 pairs of molar grade II furcation defects. Presurgical measurements were taken for the determination of aveolar crestal resorption, vertical open probing attachment, and horizontal open probing attachment. The surgical procedure consisted of sulcular incision, full-thickness facial and lingual flaps, soft tissue debridement, and root planing. One defect from each pair of furcas was treated with an expanded polytetrafluoroethylene membrane, which was left in place for 4 to 6 weeks. Postsurgery soft tissue measurements showed a reduction in probing depth and a gain in vertical and horizontal open probing attachment.

The advantages of localized ridge augmentation prior to implant placement: a staged event

This paper demonstrates the successful reconstruction of alveolar bone destroyed by advanced periodontitis and endodontic failure. It offers a staged approach that is predictable and is superior to extracting the tooth and not performing a ridge enhancement procedure. Four cases using guided tissue regeneration in combination with bone grafts prior to the placement of endosseous dental implants are discussed.

Healing in periodontal defects treated by decalcified freeze-dried bone allografts in combination with ePTFE membranes. Assessment by computerized densitometric analysis

This study quantitatively assessed radiographic changes in alveolar bone density by computer-assisted densitometric image analysis (CADIA) in periodontal defects that were treated with decalcified freeze dried bone allograft (DFDBA) alone or in combination with interproximal expanded polytetrafluroethylene membranes (ePTFE). The radiographic changes where then analyzed for correlation with the clinically assessed changes. The radiographic changes were evaluated on standardized radiographs of treated sites treated prior to, 1 week after surgery, and 6 months post-operatively. 15 patients with one pair of bilateral interproximal periodontal defects of similar morphology and > or = 6 mm in pocket depth participated. Analysis of the changes 6 months after treatment showed that the increases in density in the defect areas that received the graft were significantly greater than the adjacent areas (p < 0.001). These adjacent areas, in contrast, demonstrated significantly larger loss in radiographic density than the defect area (p < 0.001). The placement of DFDBA into the defects produced in itself significant increases in radiographic density, as illustrated by the results of one week which remained at six months. Utilization of ePTFE addition to DFDBA did not lead to additional radiographic gains in the defect area. While at one week the analysis suggested increased resorption by the combined treatment over grafting alone, such differences did not persist at 6 months post-surgery. Analysis comparing CADIA derived values for change with those of the clinical assessment revealed some associations.(ABSTRACT TRUNCATED AT 250 WORDS)

Healing in periodontal defects treated by decalcified freeze-dried bone allografts in combination with ePTFE membranes (I). Clinical and scanning electron microscope analysis

This study clinically evaluates the use of decalcified freeze-dried bone allograft (DFDBA) in conjunction with an expanded polytetrafluoroethylene (ePTFE) membrane specifically designed for the treatment of interproximal intraosseous defects. It also examines by SEM, plaque contaminated membranes retrieved from patients. 15 advanced periodontitis patients with two bilateral interproximal probing depths of > or = 6 mm participated. After hygiene phase, measurements were made to determined soft tissue recession, pocket depth, clinical attachment levels and amount of keratinized tissue. Defects from each pair were randomly treated with ePTFE plus DFDBA (experimental) or DFDBA alone (control). Measurements were made during the surgery to determine crestal resorption, defect resolution and defect fill. Membranes were removed at 4 to 6 weeks and analyzed by SEM. Each site was surgically reentered and measurements repeated at six months. Both groups showed clinical and statistically significant changes when compared to baseline (P < 0.01), but no difference between groups. The experimental group showed increased soft tissue recession vs control group, 0.9 versus 0.4 mm, and loss of keratinized tissue 1.6 versus 0.1 mm (P < 0.0001). Control sites showed a 58% bone fill while experimental sites had 70% bone fill. There were no clear patterns of microbial colonization or cell adherences in either side of the membrane. It was concluded that the presence of plaque on the membranes did not compromise the initial clinical healing during the first 4-6 weeks. Results suggest a beneficial effect with the use of either technique for the treatment of intraosseous defects.

HIV inactivation in a bone allograft

The use of exclusionary techniques in the procurement of donors for bone allografts greatly reduces chances for disease transmission. Furthermore, treatment of HIV with either chemical agents or strong acids will effectively inactivate the AIDS virus. These data are taken as indirect proof that the risk of obtaining AIDS from a freeze-dried bone allograft is highly remote. The purpose of this study is to obtain direct evidence that the processing of a demineralized freeze-dried bone allograft would render the allograft safe for human use. In Part I, human cortical bone was obtained from a cadaveric source and tested to be free of HIV contamination. The bone was spiked with 5.26 x 10(9) viral particles. This corresponded to 148 micrograms of total viral protein. In Part II, cortical bone was procured from a donor who died of AIDS. In both Parts I and II, the cortical bone was ground to yield particle sizes of 90 to 500 microns. Test samples were treated with a virucidal agent and demineralized in HCl. Control samples were left untreated. All samples were cocultivated with stimulated peripheral blood lymphocytes and assayed for p24 core protein, reverse transcriptase, and viral gag gene by polymerase chain reaction (PCR). In Part I, the HIV spiking experiment, untreated virus infected particulate bone was positive for HIV replication. Treated samples were negative when assayed for HIV. Bone samples in Part II, HIV infected bone, were positive by PCR. Replication of viable HIV could not be demonstrated after treatment. It was concluded that demineralization and treatment with a virucidal agent inactivates HIV in spiked and infected bone.

Autogenous and allogeneic bone grafts in periodontal therapy

This article is limited to a review of bone autografts and allografts, as used in periodontal therapy. The various graft materials are discussed with respect to case reports, controlled clinical trials, and human histology. Other reviewed areas are wound healing with periodontal bone grafts, tissue banking and freeze-dried bone allografts, and the use of bone grafts in guided tissue regeneration.

The use of a synthetic skin substitute as a physical barrier to enhance healing in human periodontal furcation defects: a follow-up report

The purpose of this investigation is to compare the clinical response of guided tissue regeneration using a synthetic wound dressing with open flap debridement versus open flap debridement alone in the treatment of human furcation defects. The study group was composed of 19 patients with moderate to advanced adult periodontitis and at least one bilateral pair of Class II molar furcation defects. After the hygiene phase of therapy was completed, measurements were made with calibrated periodontal probes of the clinical attachment levels, probing depths, and soft tissue recession. Paired sites were randomly selected for treatment with either open flap debridement alone (control) or open flap debridement and placement of the synthetic wound dressing over the furcation (experimental). At the time of surgery, measurements of vertical and horizontal open probing attachment were recorded. The dressing was removed 5 to 6 weeks post-surgery. The sites were reentered at 6 months to evaluate healing and to repeat all measurements. Statistical comparisons using the Wilcoxon Sign Rank Test were made between the control and experimental sites. The results of 19 pairs of Class II molar furcation defects reveal statistically significant differences between the experimental and control sites in attachment levels, probing depths, and horizontal open probing attachment. These differences were of such small magnitude that they may not be clinically relevant. There were no other significant differences for any other clinical parameter, and none of the furcations in either group was completely closed.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical evaluation of guided tissue regeneration in the treatment of maxillary class II molar furcation invasions

This investigation assessed and compared the clinical efficacy of combined open flap debridement/occlusive membrane therapy versus open flap debridement therapy alone, in the treatment of maxillary periodontal furcation defects. Seventeen patients presenting with advanced adult periodontitis, including at least one pair of Class II maxillary furcal defects, comprised the study group. Following completion of a hygienic phase of treatment, measurements were made with calibrated periodontal probes to determine soft tissue recession, probing pocket depths, and attachment levels. Each pair of furcation defects was surgically exposed and hard tissue measurements obtained. Defects were treated with either open flap debridement and a polytetrafluoroethylene periodontal membrane or open flap debridement alone. Membranes were removed at 4 to 6 weeks. Six months postsurgery, soft tissue measurements were repeated and all sites were surgically re-entered to obtain hard tissue measurements. No statistically significant differences were found in recession, probing depth reductions, clinical attachment gains, or resorption of alveolar crest height between test and control groups. Results for these parameters were inconsistent and unpredictable. Statistically significant improvements were found, however, in horizontal open probing attachment (HOPA) and vertical open probing attachment (VOPA) between experimental and control sites. The GTR procedure as used in this study likely has limited application as a therapeutic modality for Class II furcations of maxillary molars. Modifications or improvements in the procedure may result in more predictable healing of these lesions.

Clinical evaluation of the use of decalcified freeze-dried bone allograft with guided tissue regeneration in the treatment of molar furcation invasions

The purpose of this study is to evaluate the potential of decalcified freeze-dried bone allograft (DFDBA) combined with a barrier material in the treatment of human molar furcation defects (experimental) as compared to the barrier technique alone (control). Fifteen pairs of Class II or III furcation invasion defects comprised the study group. Measurements with calibrated periodontal probes were made to determine soft tissue recession, probing depth, and attachment levels. Defects from each pair were randomly selected to be treated with an expanded polytetrafluoroethylene membrane (e-PTFE) and DFDBA or the membrane alone. Additional measurements were made during surgery to determine crestal resorption, and vertical and horizontal open probing attachment. The membrane was removed 4 to 6 weeks post-insertion. Six months post-treatment, each site was surgically reentered and measurements repeated. Following either treatment, recession was minimal with statistically significant improvement in probing depth reduction and clinical attachment level gain favoring the combined technique. Hard tissue changes were comparable for alveolar crestal resorption, however, there was a distinct difference, statistically, for both horizontal and vertical bone repair favoring the use of the demineralized bone graft in combination with the e-PTFE membrane.

The osteogenic potential of two composite graft systems using osteogenin

The purpose of this study was to determine the quantity of new bone formation in critical sized calvaria defects in rats treated with two composite graft systems. The systems consisted of either a combination of the bone inductive protein (osteogenin) plus type I collagen (Os + C) or the combination of osteogenin with coralline hydroxyapatite (Os + HA). Additional treatments consisted of coralline hydroxyapatite (HA) or untreated control defects. After 28 days the calvaria were recovered and processed for quantitative radiography (radiomorphometry) and histomorphometry. Histomorphometric results were based on quantitation of regenerated trabecular bone. Results indicated that the Os + C combination produced substantially more bone than the Os + HA, HA, or control groups (P less than 0.05). Radiomorphometric assessment was based on the detection of radiopacity in the calvarial wounds. Due to the radiopaque property of HA, it was not possible to accurately quantitate the radiopacity of the regenerating bone from HA and host bone. Therefore, conclusions about the efficacy of the treatments must be derived from histomorphometric data. Results from histometric measurements of healing indicate that the Os + C combination has the greatest potential for regenerating calvarial bone defects. The potential for osteogenin in regenerating alveolar bone lost due to periodontal disease is suggested by these studies.

Regenerating bone in clinical periodontics

Bone autografts and allografts, various alloplastic materials, and guided tissue regeneration are used to reconstruct lost periodontal tissues. This paper focuses on controversies related to these therapeutic modalities as well as their role in periodontal regeneration.

A comparison of freeze-dried bone allograft and demineralized freeze-dried bone allograft in human periodontal osseous defects

This study was conducted to clinically compare freeze-dried bone allograft (FDBA) and demineralized freeze-dried bone allograft (DFDBA). Twenty-two defects (11 intrapatient pairs) in 9 patients were grafted with either DFDBA or FDBA. Evaluations were based on standardized radiographs, presurgical and postsurgical soft tissue measurements using the cemento-enamel junction as a fixed reference point, and osseous measurements at the time of surgery. Grafted sites were re-entered at a minimum of 6 months following placement. A mean osseous repair of 1.7 mm (59%) occurred with DFDBA and 2.4 mm (66%) with FDBA. A mean clinical attachment gain of 1.7 mm was obtained with DFDBA and 2.0 mm with FDBA. Probing depths decreased a mean of 2.00 mm with both DFDBA and FDBA. These findings reveal no significant differences between the two materials in primarily intraosseous defects when evaluated at a minimum 6 months postsurgery.

Comparison of decalcified freeze-dried bone allograft and porous particulate hydroxyapatite in human periodontal osseous defects

The purpose of this study was to clinically compare the healing potential of the osteoinductive decalcified freeze-dried bone allograft (DFDBA) with an osteoconductive synthetic graft, particulate porous hydroxyapatite (HA). Six patients ranging in age from 28 to 52 (mean age 42.6) participated in this investigation. They were without significant systemic disorders and had advanced periodontitis with at least two comparable periodontal defects. Each patient received initial therapy consisting of oral hygiene instruction, scaling, root planing, and occlusal adjustment as indicated. Probing pocket depth, gingival recession, attachment levels, and bleeding on probing were recorded in the posthygiene phase of therapy. Alveolar crest height and depth of osseous defect were obtained at the time of surgery. The cemento-enamel junction was used as the fixed reference point. All measurements were repeated at the time of a 6-month reentry. There was no significant difference in any of the soft tissue measurements when DFDBA and HA were compared. However, both treatment modalities reduced pocket depth and demonstrated a gain in clinical attachment levels. There was 2.2 mm of bone repair with DFDBA and 2.1 mm with HA. These values corresponded to a percent defect fill of 61% for DFDBA and 53% for HA. These values were likewise not statistically different.