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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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 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.

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.