Human histologic evaluation of the use of the dental putty for bone formation in the maxillary sinus: case series.

A proof-of-principle study was conducted to assess the safety and efficacy of dental putty as an alternative sinus augmentation biomaterial. Six healthy patients requiring a total of 10 sinus augmentations received sinus augmentations. All patients volunteered and signed an informed consent based on the Helsinki declaration of 1975, as revised in 2000. The sinus augmentation was performed under local anesthesia with a mucoperiosteal flap elevated to expose the buccal wall of the maxillary sinus. The space was then filled with the dental putty in several increments, and the window was covered with an absorbable collagen membrane. Biopsies were harvested from all 10 treated sinuses using a 3-mm trephine bur at the time of implant placement at either 6 or at 9 months after sinus augmentation. All patients completed the study without complications, except for 1 patient who reported fistulas at 1 and 2 months after the surgery. Clinical reentry revealed that regenerated bone on the osteotomy site was soft and immature. The ground sections of the biopsied cores revealed minimum amounts of trabeculation surrounded by an abundant array of irregular-shaped residual alloplastic particles embedded in loose connective tissue. The present study's findings revealed inadequate bone formation, although the material appears to be bioinert as there is no elicitation of inflammatory response.

Pilot clinical and histologic evaluations of a two-piece zirconia implant.

An investigation was conducted to evaluate the clinical and histologic results of bone and soft tissue healing around a two-piece zirconia dental implant in a human model. A healthy female patient requiring tooth replacement with dental implants received a two-piece zirconia implant together with conventional titanium implants to be implemented in a prosthesis. Clinical and radiographic evaluations at 6 months revealed stable osseointegrated zirconia and titanium dental implants. Light microscopy and backscatter scanning electron microscopic analyses confirmed the biocompatibility and achievement of osseointegration, in addition to maintenance of the crestal bone level. The findings suggest that the bone-to-implant contact with a zirconia implant surface is sufficient to provide clinical and histologic evidence of osseointegration. The biopsied two-piece zirconia dental implant with platform switching demonstrated osseointegration occlusal to the implant-abutment junction, eliminating the significance of the microgap.

The feasibility of demineralized bone matrix and cancellous bone chips in conjunction with an extracellular matrix membrane for alveolar ridge preservation: a case series.

An investigation was conducted to test the feasibility of demineralized bone matrix and cancellous bone chips in a reverse-phase medium carrier (DynaBlast) in concert with an extracellular matrix membrane (DynaMatrix) to provide hard and soft tissue regeneration for the purpose of a ridge preservation procedure. Nine patients requiring extraction of 30 maxillary teeth were grafted with DynaBlast and DynaMatrix. Twenty sites attained primary flap closure over the grafted area (primary healing intention group), while 10 sites were assigned randomly to the secondary healing intention group, in which primary flap closure over the membrane was not achieved. Clinical and radiographic evaluations at 6 months revealed comparable bone formation for both groups. Histologic analyses of 21 harvested soft and hard tissue core biopsies revealed absence of the remnant membrane and consistent patterns of new bone formation. The efficacy and safety of DynaBlast and DynaMatrix have been validated clinically and histologically to preserve the dimensions of the alveolar process.

The clinical and histologic efficacy of xenograft granules for maxillary sinus floor augmentation.

The objective of this study was to investigate the potential of xenograft (cancellous bovine bone) granules to form vital bone in non-natural bone-forming areas of maxillary sinuses. Fourteen sinus augmentations were performed in 14 patients. Surgical outcomes were uneventful, and sufficient radiopaque volume was present radiographically to place dental implants in all sites. Clinical reentry at 6 months revealed bone formation at the osteotomy site. Histologic evaluation of the obtained bone cores revealed that xenograft granules were integrated and surrounded by woven bone and lamellar bone that were in close contact with the particles. The average percentage of newly formed bone at 6 months was 27.5% ± 8.9%. Vital bone formation using the xenograft granules was supported by both clinical and histologic evidence.

The clinical efficacy of DynaMatrix extracellular membrane in augmenting keratinized tissue.

This study was conducted to compare the efficacy and feasibility of an extracellular matrix membrane (DynaMatrix) with that of an autogenous gingival graft in increasing the width of attached keratinized tissue. Six patients with an inadequate amount of attached keratinized gingiva on the bilateral facial aspect of the mandibular posterior teeth were recruited for this study. The defect sites were randomly subjected to receive either test (DynaMatrix membrane) or control (autogenous gingival graft) treatment. Both test and control sites achieved a clinically significant increase in the amount of keratinized gingiva, and the DynaMatrix membrane-treated sites blended well with the surrounding tissue, with a better appearance when compared to the autogenous gingival grafted sites. The biopsy specimens of both test and control sites appeared to be similar histologically, with mature connective tissue covered by keratinized epithelium. The results of both clinical and histologic evaluations have suggested a potential application of an extracellular matrix membrane in achieving gingival augmentation.

Minimally invasive alveolar ridge augmentation procedure (tunneling technique) using rhPDGF-BB in combination with three matrices: a case series.

This study investigated a minimally invasive surgical procedure for alveolar ridge augmentation that combined recombinant human platelet-derived growth factor BB (rhPDGF-BB) and three different matrices. The minimally invasive tunneling ridge augmentation procedure was applied to 12 patients randomized into three groups: rhPDGF-BB (0.3 mg/mL) was combined with freeze-dried bone allograft (FDBA; group A), anorganic bovine bone graft (ABBG; group B), or anorganic bovine bone graft/mineralized collagen bone substitute (ABBG/MCBS; group C). Computed tomography (CT) scans were obtained presurgically and prior to 14-week re-entry surgery. Clinical reentry revealed adequate bone volume to place implants in all patients in groups A and B and two of four patients in group C. Trephine core biopsies were obtained and evaluated by microCT, backscatter scanning electron microscopy (BE-SEM), and light microscopy. New bone formation was consistently observed with BE-SEM and histologic analysis for group A and B specimens. Newly formed woven and lamellar bone were in close contact with graft particles. The ABBG/MCBS specimens (group C) had more variable results, with fibrous encapsulation of graft particles and limited histologic evidence of new bone formation. Within the limits of this study, the FDBA and ABBG carriers appear to be appropriate scaffolds to deliver rhPDGF-BB for ridge augmentation via minimally invasive surgical techniques.

Human histologic evaluation of mineralized collagen bone substitute and recombinant platelet-derived growth factor-BB to create bone for implant placement in extraction socket defects at 4 and 6 months: a case series.

The objective of this pilot study was to assess whether mineralized collagen bone substitute (MCBS) combined with recombinant human platelet-derived growth factor-BB (0.3 mg/mL) would generate adequate viable bone in buccal wall extraction defects to accommodate implant placement. The primary outcome variable was bone quality, as measured by microcomputed tomography and histologic evaluation. This was successfully accomplished in all eight specimens obtained from seven patients. The secondary outcome variables were bone quality and quantity as observed clinically, radiographically, and by the primary stability of implants at the time of placement. Soft tissue healing was excellent, and there were no unanticipated adverse events. Robust bone formation accompanied by MCBS resorption was evident in all 4- and 6-month specimens. This was accomplished without barrier membranes.

The efficacy of demineralized bone matrix and cancellous bone chips for maxillary sinus augmentation.

Demineralized bone matrix and cancellous bone chips in a reverse-phase medium carrier (DynaBlast, Keystone Dental) were used to augment the maxillary sinuses in 8 patients requiring 10 sinus augmentations. Clinical reentry after 6 to 7 months (mean, 6.2 months) and computed tomographic scan evaluation at 5 months demonstrated new bone formation as well as sufficient radiopaque volume to place implants in all sites. Microcomputed tomographic evaluation and histomorphometric analysis of sinus core biopsies confirmed the formation of new bone and demonstrated three distinctive mineralization patterns that have been previously described. DynaBlast can be considered a viable alternative to the use of autogenous bone or other types of grafting materials.

Prospective 1-Year Study of Immediately Loaded Implants: 8-Patient Case Series Report.

The goal of this case series report is to demonstrate the predictability of providing immediate restorations with an implant specifically designed to achieve high primary stability, and to report on 12-month survival outcomes. Twenty-nine implants were placed in eight patients with various tooth-replacement needs, from single teeth to partially edentulous spans to fully edentulous mandibles. A new tapered-implant system (The Marc Nevins, Little Implant) was utilized that incorporates a self-tapping thread design with a thread pitch and thread lead to improve primary stability at insertion. All implants were placed with a minimum insertion torque of 45 Ncm. Four immediate implants and two early placements at extraction sites were included in the cohort. Twenty-seven implants were clinically successful at 1 year. Two implants in a healed ridge were found to have failed at 6 weeks postoperative in one patient wearing an ill-fitting removable partial denture. The radiographic crestal marginal bone levels were recorded in millimeters from the top of the implant platform to the first bone-to-implant contact. The mean crestal marginal bone level change was -0.57 ± 0.82 mm. This case series report demonstrates the ability of an implant designed for high primary stability to achieve successful integration in the presence of an immediate restoration for various clinical presentations, including single-tooth, multi-unit, and edentulous cases.

Human histologic evidence of a connective tissue attachment to a dental implant.

This human proof-of-principle study was designed to investigate the possibility of achieving a physical connective tissue attachment to the Laser-Lok microchannel collar of a dental implant. Its 2-mm collar has been micromachined to encourage bone and connective tissue attachment while preventing apical migration of the epithelium. Implants were harvested with the surrounding implant soft and hard tissues after 6 months. The histologic investigation was conducted with light microscopy, polarized light, and scanning electron microscopy.

A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots.

The objective of this investigation was to determine the fate of thin buccal bone encasing the prominent roots of maxillary anterior teeth following extraction. Resorption of the buccal plate compromises the morphology of the localized edentulous ridge and makes it challenging to place an implant in the optimal position for prosthetic restoration. In addition, the use of Bio-Oss as a bone filler to maintain the form of the edentulous ridge was evaluated. Nine patients were selected for the extraction of 36 maxillary anterior teeth. Nineteen extraction sockets received Bio-Oss, and seventeen sockets received no osteogenic material. All sites were completely covered with soft tissue at the conclusion of surgery. Computerized tomographic scans were made immediately following extraction and then at 30 to 90 days after healing so as to assess the fate of the buccal plates and resultant form of the edentulous sites. The results were assessed by an independent radiologist, with a crest width of 6 mm regarded as sufficient to place an implant. Those sockets treated with Bio-Oss demonstrated a loss of less than 20% of the buccal plate in 15 of 19 test sites (79%). In contrast, 12 of 17 control sockets (71%) demonstrated a loss of more than 20% of the buccal plate. In conclusion, the Bio-Oss test sites outperformed the control sites by a significant margin. No investigator was able to predict which site would be successful without the grafting material even though all were experienced clinicians. This leads to the conclusion that a patient has a significant benefit from receiving grafting materials at the time of extraction.

Three-dimensional micro-computed tomographic evaluation of periodontal regeneration: a human report of intrabony defects treated with Bio-Oss collagen.

This study utilized three-dimensional micro-computed tomography (micro-CT) to evaluate the regenerative response to Bio-Oss Collagen when used alone or in combination with a Bio-Gide bilayer collagen membrane for the treatment of four intrabony defects (5 to 7 mm) around single-rooted teeth. The micro-CT observations are compared to the clinical, radiographic, and histologic results, which have been previously reported. After reflecting a full-thickness flap, thorough degranulation and root planing were accomplished. Bio-Oss Collagen was then used to fill the defects, and in two cases a Bio-Gide membrane was placed over the filled defect. Radiographs, clinical probing depths, and attachment levels were obtained before treatment and immediately preceding en bloc resection of teeth and surrounding tissues 9 months later. A mean pocket depth reduction of 5.75 mm and mean clinical attachment level gain of 5.25 mm were recorded. The histologic evaluation demonstrated the formation of a complete new attachment apparatus with new cementum, periodontal ligament, and alveolar bone at the level of and coronal to the calculus reference notch. Micro-CT evaluation confirmed the histologic results and demonstrated the absence of ankylosis or root resorption for all specimens. This human histologic study demonstrated that Bio-Oss Collagen has the capacity to facilitate regeneration of the periodontal attachment apparatus when placed in intrabony defects. Micro-CT observations confirmed the histologic results and enhanced the three-dimensional understanding of periodontal wound healing. The results indicate that micro-CT may be useful for three-dimensional evaluation of periodontal regenerative procedures.

Periodontal regeneration in humans using recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and allogenic bone.

BACKGROUND: Purified recombinant human platelet-derived growth factor BB (rhPDGF-BB) is a potent wound healing growth factor and stimulator of the proliferation and recruitment of both periodontal ligament (PDL) and bone cells. The hypothesis tested in this study was that application of rhPDGF-BB incorporated in bone allograft would induce regeneration of a complete new attachment apparatus, including bone, periodontal ligament, and cementum in human interproximal intrabony defects and molar Class II furcation lesions. METHODS: Nine adult patients (15 sites) with advanced periodontitis exhibiting at least one tooth requiring extraction due to an extensive interproximal intrabony and/or molar Class II furcation defect were entered into the study. Eleven defects were randomly selected to receive rhPDGF-BB. Following full-thickness flap reflection and initial debridement, the tooth roots were notched at the apical extent of the calculus, the osseous defects were thoroughly debrided, and the tooth root(s) were planed/prepared. The osseous defects were then filled with demineralized freeze-dried bone allograft (DFDBA) saturated with one of three concentrations of rhPDGF-BB (0.5 mg/ml, 1.0 mg/ml, or 5.0 mg/ml). Concurrently, four interproximal defects were treated with a well accepted commercially available graft (anorganic bovine bone in collagen, ABB-C) and a bilayer collagen membrane. Radiographs, clinical probing depths, and attachment levels were obtained preoperatively (at baseline) and 9 months later. At 9 months postoperatively, the study tooth and surrounding tissues were removed en bloc. Clinical and radiographic data were analyzed for change from baseline by defect type and PDGF concentration. The histologic specimens were analyzed for the presence of regeneration of a complete new attachment apparatus coronal to the reference notch. RESULTS: The post-surgical wound rapidly healed and was characterized by firm, pink gingivae within 7 to 10 days of surgery. There were no unfavorable tissue reactions or other safety concerns associated with the treatments throughout the course of the study. In rhPDGF/allograft sites, the vertical probing depth (vPD) reduction for interproximal defects was 6.42 +/- 1.69 mm (mean +/- SD) and clinical attachment level (CAL) gain was 6.17 +/- 1.94 mm (both P < 0.01). Radiographic fill was 2.14 +/- 0.85 mm. Sites filled with ABB-C had a PD reduction and CAL gain of 5.75 +/- 0.5 and 5.25 +/- 1.71, respectively. Furcation defects treated with rhPDGF/allograft exhibited a mean horizontal and vertical PD reduction of 3.40 +/- 0.55 mm (P < 0.001) and 4.00 +/- 1.58 mm (P < 0.005), respectively. The CAL gain for furcation defects was 3.2 +/- 2.17 mm (P < 0.030). Histologic evaluation revealed regeneration of a complete periodontal attachment apparatus, including new cementum, PDL, and bone coronal to the root notch in four of the six interproximal defects and all evaluable (four of four) furcation defects treated with PDGF. Two of the four interproximal intrabony defects treated with ABB-C and membrane exhibited regeneration. CONCLUSIONS: Use of purified rhPDGF-BB mixed with bone allograft results in robust periodontal regeneration in both Class II furcations and interproximal intrabony defects. This is the first report of periodontal regeneration demonstrated histologically in human Class II furcation defects.

Periodontal regeneration in human Class II furcations using purified recombinant human platelet-derived growth factor-BB (rhPDGF-BB) with bone allograft.

This human clinical trial evaluated the clinical and histologic response to recombinant human platelet-derived growth factor-BB (rhPDGF-BB) delivered in bone allograft for the treatment of advanced Class II furcation defects. Three mandibular and one maxillary molar furcation defects were treated: Two received 0.5 mg/mL and two received 1.0 mg/mL rhPDGF-BB, in all cases mixed with DFDBA. Clinical probing depths and attachment levels were obtained presurgically and 9 months postsurgical, after which the teeth and surrounding tissues were removed en bloc. Both concentrations of rhPDGF-BB resulted in substantially improved horizontal (mean 3.5 mm) and vertical (mean 4.25 mm) probing depths and attachment levels (mean 3.75 mm). Histologic evaluation revealed periodontal regeneration, including new bone, cementum, and periodontal ligament coronal to the reference notch. Regeneration was also present coronal to the original osseous crest In one case where an enamel projection extended into the fornix of the furcation, new calcified tissue with new inserting connective tissue fibers was observed over the enamel. This study documented the favorable tissue response to rhPDGF-BB treatment at both the clinical and microscopic levels, provided the first human histologic evidence that new calcified tissue with inserting collagen fibers can occur over enamel projections within furcations, and demonstrated for the first time that complete periodontal regeneration can be achieved in advanced Class II furcation defects using a combination of purified recombinant growth factor and bone allograft.

Evaluation of periodontal regeneration following grafting intrabony defects with bio-oss collagen: a human histologic report.

This study evaluated the clinical, radiographic, and histologic response to Bio-Oss Collagen when used alone or in combination with Bio-Gide bilayer collagen membrane for the treatment of four intrabony defects (5 to 7 mm) around single-rooted teeth. After reflecting a full-thickness flap, thorough degranulation and root planing were accomplished. In all cases, Bio-Oss Collagen was then used to fill the defects, and in two cases, a Bio-Gide membrane was placed over the filled defect. Radiographs, clinical probing depths, and attachment levels were obtained before treatment and immediately preceding en bloc resection of teeth and surrounding tissues 9 months later. Reduction in pocket depth and gain in clinical attachment level were observed for both treatment protocols. The histologic evaluation demonstrated the formation of a complete new attachment apparatus, evidencing periodontal regeneration that varied with defect morphology. This human histologic study demonstrated that Bio-Oss Collagen has the capacity to induce regeneration of the periodontal attachment apparatus when placed in intrabony defects.

A prospective 9-month human clinical evaluation of Laser-Assisted New Attachment Procedure (LANAP) therapy.

This investigation was designed and implemented as a single-center, prospective study to evaluate the clinical response to the Laser-Assisted New Attachment Procedure (LANAP). Eight patients with advanced periodontitis were enrolled and treated with full-mouth LANAP therapy and monitored for 9 months. Fullmouth clinical measurements, including clinical attachment level (CAL), probing depth (PD), and recession, were provided at baseline and after 9 months of healing by a single calibrated examiner, including a total of 930 sites and 444 sites with initial PD equal to or greater than 5 mm. Clinical results for the 930 sites measured pre- and postoperatively revealed that mean PD was reduced from 4.62 ± 2.29 mm to 3.14 ± 1.48 mm after 9 months (P < .05). CAL decreased from 5.58 ± 2.76 mm to 4.66 ± 2.10 mm (P < .05) and recession increased from 0.86 ± 1.31 mm to 1.52 ± 1.62 after 9 months (P < .05). For the subset of 444 sites with initial PD greater than or equal to 5 mm, the PD decreased from 6.50 ± 2.07 mm to 3.92 ± 1.54 mm (P < .05) and CAL decreased from 7.42 ± 2.70 mm to 5.78 ± 2.06 mm (P < .05). As demonstrated by the clinical evaluation, the majority of treated sites demonstrated clinical improvement. LANAP therapy should be further investigated with long-term clinical trials to compare the stability of clinical results with conventional therapy.

Platform switching versus conventional technique: a randomized controlled clinical trial.

In this controlled prospective study, 53 patients treated at four study centers were randomly assigned to receive either (test) implants with platform switching built into their design or similar nonplatform-switched controls (same manufacturer, surface treatment, etc) for treatment of single and multiple edentulous sites in all four quadrants. Radiographs taken at the time of implant placement, definitive restoration delivery, and 1-year follow-up found significantly less crestal bone loss around the test implants (0.25 mm) compared to the controls (0.65 mm). Notably, bone loss around the control implants had declined by the 1-year follow-up point.

Human histologic assessment of a platform-switched osseointegrated dental implant.

This case report examined crestal bone level maintenance surrounding a platform-switched implant that was retrieved due to prosthetic difficulty. The retrieved platform-switched implant threads demonstrated tight contact with the surrounding bone and demonstrated both radiographic and histologic features that were indicative of successful osseointegration. Very high bone-to-implant contact (BIC) without epithelial downgrowth to the implant thread was noted. The BIC consisted of a combination of newly formed bone and native bone. The buccal and lingual bone levels coincided with the original platform position noted at the time of the surgery, and did not appear to resorb at all. The result of the present investigation confirms the maintenance of the crestal bone level for platform-switched implants.

Recombinant human platelet-derived growth factor BB for reconstruction of human large extraction site defects.

This study investigated the ability of growth factor-enhanced matrices combined with a tenting screw scaffolding system and resorbable membrane to regenerate large alveolar extraction site defects. Eight patients were randomized to treatment either with a bovine or equine matrix mixed in a ratio of 1.0 mL (0.3 mg/mL) recombinant human platelet-derived growth factor BB (rh-PDGF-BB) per gram of xenograft and allowed to absorb for 10 minutes. Tenting screws were used to provide additional support, and the growth factor-enhanced particulate matrix was incrementally placed and condensed into the defect and covered by a resorbable membrane. Reentry surgery after 5 months allowed for trephine core biopsies and implant placement. All sites healed well with evidence of bonelike hard tissue that was confirmed histologically as vital bone around the remaining graft particulate in both treatment groups. The results of this study demonstrate the capability of growth factor-enhanced matrices combined with tenting screws and a resorbable membrane to support the reconstruction of large extraction site defects.

Ridge preservation with and without primary wound closure: a case series.

The purpose of this study was to determine the clinical and histologic efficacy of the combination of alloplastic biphasic calcium phosphate composed of 30% hydroxyapatite and 70% Β-tricalcium phosphate (Osteon II) and a cross-linked collagen membrane used to reconstruct an extraction socket with new bone formation. Twelve patients, from two private dental practices, requiring extraction of maxillary and mandibular nonmolar teeth (n = 30) received both Osteon II (0.5- to 1.0-mm particle size) and the collagen membrane. The primary healing intention group (group A, n = 12) received primary flap closure over the membrane, while in the secondary healing intention group (group B, n = 18), the membrane was left exposed. Early wound healing seemed to be slower in group B when compared to group A, but the difference was not noticeable after 4 weeks. Clinical reentry revealed that the dimensions of the ridge appeared to be maintained in both groups, and internal socket bone fill was evident. The grafted area appeared to be well vascularized, but clinically visible graft particles were noted in some cases. Light microscopic analysis revealed the formation of new bone directly apposing the surfaces of graft particles and bridging the space between them, indicating that the graft material behaved as an osteoconductive scaffold. The mean amount of vital bone in group A was 40.3% ± 7.8%, while the remaining graft was 6.0% ± 4.0%. The mean amount of vital bone in group B was 47.3% ± 11.3%, while the remaining graft was 18.0% ± 20.0%. The absence of primary flap closure did not affect the percentage of vital bone formation or residual graft.