Healing responses to grafting of combined collagen-decalcified bone in periodontal defects in dogs

Core Ossification of Bone Morphogenetic Protein-2-Loaded Collagenated Bone Mineral in the Sinus

The objective of this study was to investigate in vitro release kinetics and ossification patterns of bone morphogenetic protein-2-soaked collagenated porcine bone mineral (BMP-2/CPBM) in rabbit sinuses. Release kinetics of BMP-2/CPBM was determined in vitro up to 56 days. In 16 rabbits, BMP-2/CPBM (BMP group) and CPBM alone (control group) were bilaterally grafted in both sinuses. After 4 (N = 8) and 12 (N = 8) weeks, radiographic and histologic analyses were performed. Approximately 40% of BMP-2 was released from CPBM during 3 days in vitro; release maintained at a reduced level until day 56. In vivo, new bone formation in BMP group was dominant at the center and decreased toward the borders of the sinus, while it mainly possessed close to the sinus membrane and basal bone in control group. At the center, significantly more new bone was found in BMP group compared to control group at 4 weeks (29.14% vs. 16.50%; p < 0.05). The total augmented volume of BMP group was significantly greater than control group at 4 (370.13 mm³ vs. 299.32 mm³) and 12 (400.40 mm³ vs. 290.10 mm³) weeks (p < 0.05). In conclusion, BMP-2/CPBM demonstrated a core ossification with a greater augmented volume and new bone formation in the center of the sinus compared to CPBM alone. Impact statement The center of the augmented maxillary sinus tends to show a slower and inferior new bone formation compared to the sites near the sinus membrane and basal bone. In this study, bone morphogenetic protein-2 (BMP-2) loaded onto collagenated porcine bone mineral (CPBM) resulted in a greater augmented volume and new bone formation at the center of the grafted sinus compared to CPBM alone. Therefore, BMP-2-added CPBM in maxillary sinus augmentation may potentially be beneficial to the clinicians, in terms of accelerating the new bone formation at the center area where the apical half of the implant fixture usually places.

The Combined Effect of Bioactive Glass and Platelet-Rich Fibrin in Treating Human Periodontal Intrabony Defects - A Clinicoradiographic Study

Background:

Platelets are richest source for cytokine and growth factors which are two important components for the re-establishment of bone and maturation of the soft tissue.

Aims and Objective:

The additive effect of PRF along with a synthetic bone graft material in treating human intrabony periodontal defects has been evaluated in this study. The appropriate use of platelet-rich fibrin (PRF) as an alternate comfortable graft material to restore the lost periodontal tissues has been well documented and has given clinically promising outcome.

Materials and Method:

Platelet-rich fibrin (PRF) is prepared from patient's own blood which is autologous in nature. Perio Glas (PG) is an easy to use synthetic absorbable osteostimulative as well as osteoconductive bone graft material. The selected 30 sites were randomly divided into two groups such as Test (15 sites using PRF) and Control (15 sites without PRF).

Results:

At the end of Six months, the post-operative evaluations revealed significant reduction in PPD and gain in CAL. Radiographic evidence of bone formation was also noticed. The incorporation of PRF with synthetic bone graft (perioglas) produces effective and rapid periodontal regeneration with improved healing in intrabony osseous defects. The PRF group showed a mean Radiographic Defect Fill (RDL) of 1.24 ± 0.04 compared with 0.79 ± 0.07 of control group which is statistically significant.

Conclusion:

This combination technique can be used as an alternate grafting modality for the treatment of intrabony periodontal defects with satisfactory clinical consequences.

Comparison of Attachment and Proliferation of Human Gingival Fibroblasts on Different Collagen Membranes

Background and Aim

Human gingival fibroblasts cultured on collagen membrane as an alternative treatment method used in tissue regeneration can lead to improved results in root coverage. The aim of this study was to evaluate the human gingival fibroblast proliferation and adhesion cultured on three types of collagen membranes.

Materials and Methods

In this in vitro study, first-line human gingival fibroblast cells (HGF1-RT1) prepared and cultured on three membranes, including porcine pericardium (PP) (Jason, Botiss dental), human pericardium (HP) (Regen, Faravardeh Baft Iranian), and glutaraldehyde cross-linked (GC) (BioMend Extend, Zimmer Dental). Cell survival was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) after 24, 48, and 72 h and 7 days. Furthermore, morphology and adhesion of cells on the membrane were evaluated after 1 and 7 days by electron microscopy (scanning electron microscopy [SEM]). Statistical analysis was performed using two-way ANOVA with a significance level of 0.05.

Results

Based on the results of MTT, cell survival on HP and PP membranes after 7 days significantly increased (P < 0.001), but for the GC membrane, it was reduced after 7 days (P = 0.031). Cell survival on HP and PP membranes did not differ (P = 1) and was more than GC (P < 0.001). SEM images showed that the adhesion of cells was better on HP and PP membranes than GC.

Conclusion

The results of this study showed that natural collagen membranes (HP and PP) similarly support proliferation and adhesion of gingival fibroblasts. Survival and adhesion of gingival fibroblasts on cross-linked collagen membrane was less than two other membranes.

Clinical and radiographic evaluation of nanocrystalline hydroxyapatite with or without platelet-rich fibrin membrane in the treatment of periodontal intrabony defects

Background:

Nano-sized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties. Nanocrystalline hydroxyapatite (NcHA) binds to bone and stimulate bone healing by stimulation of osteoblast activity. Platelet-rich fibrin (PRF), an intimate assembly of cytokines, glycan chains, and structural glycoproteins enmeshed within a slowly polymerized fibrin network, has the potential to accelerate soft and hard tissue healing. The present study aims to explore the clinical and radiographical outcome of NcHA bone graft with or without PRF, in the treatment of intrabony periodontal defects.

Materials and Methods:

In a split-mouth study design, 20 patients having two almost identical intrabony defects with clinical probing depth of at least 6 mm were selected for the study. Selected sites were randomly divided into two groups. In Group I, mucoperiosteal flap elevation followed by the placement of NcHA was done. In Group II, mucoperiosteal flap elevation, followed by the placement of NcHA with PRF was done. Clinical and radiographic parameters were recorded at baseline and at 6-month postoperatively.

Results:

Both treatment groups showed a significant probing pocket depth (PPD) reduction, clinical attachment gain, increase bone density 6-month after surgery compared with baseline. However, there was a significantly greater PPD reduction and clinical attachment gain when PRF was added to NcHA.

Conclusion:

The NcHA bone graft in combination with PRF demonstrated clinical advantages beyond that achieved by the NcHA alone.

Clinical effect of autologous platelet-rich fibrin in the treatment of intra-bony defects: a controlled clinical trial

AIM

Platelet-rich fibrin (PRF) may be considered as a second-generation platelet concentrate widely used to accelerate soft and hard tissue healing because of presence of many growth factors. The present study aimed to investigate the clinical and radiological effectiveness of autologous PRF in the treatment of intra-bony defects of chronic periodontitis patients.

MATERIAL AND METHODS

Thirty-two intra-bony defects (one site/patient) were treated either with autologous PRF or a conventional open flap debridement alone. Clinical parameters such as plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), clinical attachment level (CAL) and gingival marginal level (GML) were recorded at baseline and 9 months post-operatively. In both the groups, by using the image analysis software intra-bony defect fill was calculated on standardized radiographs (from the baseline and 9 months).

RESULTS

For all clinical and radiographic parameters test group was performed better than control group, and the difference was found to be statistically significant. Furthermore, images analysis revealed significantly greater bone fill in the test group compared with control (46.92%versus 28.66 %). Mean PD reduction (4.56 ± 0.37>3.56 ± 0.27) and CAL gain (3.69 ± 0.44>2.13 ± 0.43) in test group was found to be more compared with that of control group. In the test group, PD of >4 mm has highest percentage of PD reduction (68.9%) and CAL gain (61.6%). On frequency distribution analysis, there was no more difference for PD reduction in both the groups but CAL gain was much more in the test group than the control group.

CONCLUSIONS

Within the limit of the present study, there was greater reduction in PD, more CAL gain and greater intra-bony defect fill at sites treated with PRF than the open flap debridement alone.

Effect of new bone substitute materials consisting of collagen and tricalcium phosphate

The purpose of this study was to investigate the effect of new bone substitute materials consisting of collagen and tricalcium phosphate (TCP). Prior to the experiment, mandibular dog teeth were extracted. After 3 months, specific cavities were prepared on the alveolar ridge. In one group, cavities were filled with collagen sponge (CS group), in the other, cavities were filled with TCP sponge (TCP group). Cavities with no fillings (Cont group) were created as controls. Mandibular bone was evaluated histopathologically at experimental time periods of 1, 2, 4, and 8 weeks. Due to the non critical inflammatory symptoms that each group showed throughout all the time periods investigated, a low irritation level was observed. Absorption of material was almost complete at after 4 weeks in the CS group, and at after 8 weeks in the TCP group. At the top of the cavity, the TCP group exceeded the Cont group in amount of neogenesis at after 8 weeks. The materials examined in this study showed good osteoconduction and biodegradable character. The TCP Group, in particular, showed highly acceptable results, demonstrating that the materials used were excellent candidates as bone substitute materials.

Potential of bioactive glass particles of different size ranges to affect bone formation in interproximal periodontal defects in dogs

BACKGROUND

The aim of this study was to compare the potential of bioactive glass particles of different size ranges to affect bone formation in periodontal defects, using the guided tissue regeneration model in dogs.

METHODS

In six dogs, 2-wall intrabony periodontal defects were surgically created and chronified on the mesial surfaces of mandibular third premolars and first molars bilaterally. After 1 month, each defect was randomly assigned to treatment with bioabsorbable membrane in association with bioactive glass with particle sizes between 300 and 355 microm (group 1) or between 90 and 710 microm (group 2), membrane alone (group 3), or negative control (group 4). The dogs were sacrificed 12 weeks after surgeries, and histomorphometric measurements were made of the areas of newly formed bone, new mineralized bone, and bioactive glass particle remnants.

RESULTS

With regard to the area of bioactive glass particle remnants, there was a statistically significant difference between groups 1 and 2, favoring group 1. There were greater areas of mineralized bone in groups 1 and 2 compared to groups 3 and 4 (P <0.05).

CONCLUSION

The bioactive glass particles of small size range underwent faster resorption and substitution by new bone than the larger particles, and the use of bioactive glass particles favored the formation of mineralized bone.

Tricalcium phosphate and glutaraldehyde crosslinked gelatin incorporating bone morphogenetic protein--a viable scaffold for bone tissue engineering

Bone defects caused by various etiologies must be filled with suitable substances to promote bone repair. Autogenous iliac crest graft is most frequently used, but is often associated with morbidities. Several bone graft substitutes have been developed to provide osteoconductive matrices as well as to enhance osteoinductivity. A tricalcium phosphate and glutaraldehyde crosslinked gelatin (GTG) scaffold, incorporated with bone morphogenetic proteins (BMPs), was developed to provide an alternative mean of bone tissue engineering. This study investigated differences between GTG and BMP-4 immobilized GTG (GTG-BMP) scaffolds on neonatal rat calvaria osteoblast activities. The GTG scaffold possessed an average pore size of 200 microm and a porosity of 75%. HE staining revealed uniform cell distribution throughout the scaffold 24 h post cell seeding. Alkaline phosphatase (ALP) activity of the GTG samples increased initially and then stabilized at 3 weeks postseeding. ALP activity of the GTG-BMP samples was similar to that of the GTG samples in the second and third weeks, but it continued increasing and became significantly greater than that of the GTG samples by the fourth week. Gla-type osteocalcin (Gla-OC) activity of the GTG-BMP samples was initially lower, but also became significantly greater than that of the GTG samples by the fourth week. An HE stain revealed greater numbers of attached cells and a richer matrix deposits in the GTG-BMP samples. A von Kossa stain showed larger mineralizing nodules, in greater numbers, after 4 weeks of in vitro cultivation. These findings suggest that the GTG scaffold provides an excellent porous structure, conductive to greater cell attachment and osteoblast differentiation, and that utility can be significantly enhanced by the inclusion of BMPs. A GTG-BMP scaffold holds promise as a superior bioactive material for bone tissue engineering.

Effects of chitosan nonwoven membrane on periodontal healing of surgically created one-wall intrabony defects in beagle dogs

The purpose of this study was to investigate the periodontal regenerative effects of a chitosan nonwoven membrane applied to surgically created preclinical one-wall intrabony defects in beagle dogs. One-wall intrabony defects (4 x 4 x 4 mm) were surgically created bilaterally in the mandibular second and fourth premolars of six beagle dogs. The surgical control group received a flap operation only. The resorbable-membrane (RM) group was treated with resorbable membrane. The chitosan-nonwoven-membrane (CNWM) group was treated with chitosan nonwoven membrane. The amount of junctional epithelium migration and the amount of connective tissue adhesion did not show any statistically significant differences among the groups. However, the amount of suprabony cementum regeneration, intrabony cementum regeneration, and alveolar bone regeneration showed significant differences (p < 0.05) between CNWM site group and control group. The results demonstrate the regenerative effects of the chitosan nonwoven membrane in one-wall intrabony defects of beagle dogs. The chitosan nonwoven membrane has the potential to support the cementum and bone regeneration, possibly by providing the conditions needed for guided tissue regeneration in the one-wall intrabony periodontal defects of beagle dogs.

The Effects of a Bioabsorbable Barrier Membrane Containing Safflower Seed Extracts on Periodontal Healing of 1-Wall Intrabony Defects in Beagle Dogs

BACKGROUND

Recently, there has been much research done into the regenerative potential of materials used in oriental medicine. In several studies, evidence was found that these materials have an effect on bone regeneration. Among these materials, safflower seeds are of particular interest as they have been used for the treatment of blood stasis, bone fracture, and osteoporosis in traditional Korean medicine. In addition, they are known to have anti-inflammatory effects. The objective of this study is to evaluate the periodontal tissue regenerative effects of a bioabsorbable barrier membrane (polylactide glycolic acid electro-spun non-woven membrane) containing safflower seed extracts applied to surgically created 1-wall intrabony defects in beagle dogs.

METHODS

One-wall intrabony defects were surgically created bilaterally at the mesial and distal sides of the mandibular second premolars and mesial side of the fourth premolars. These defects were randomly assigned either to the surgical control group which received a flap operation only or to one of two experimental groups consisting of defects which received a guided tissue regenerative procedure with either a bioabsorbable membrane (PLGA) or a bioabsorbable membrane containing safflower seed extracts (SSE/PLGA). The dogs were sacrificed 8 weeks after the operation, and a comparative histological examination was done.

RESULTS

The new cementum formation was 2.49+/-0.41 mm in the surgical control group, 3.22+/-0.35 mm in the PLGA group, and 3.67+/-0.82 mm in the SSE/PLGA group. The extent of new cementum formation in barrier groups was significantly different from the surgical control group (P <0.05). The amount of intrabony cementum was 1.75+/-0.06 mm, 2.40+/-0.33 mm, and 2.70+/-0.81 mm for the surgical control group, the PLGA group, and the SSE/PLGA group, respectively; the amount of infrabony cementum in the barrier groups was significantly different from the surgical control group (P<0.05). The value of the suprabony cementum was 0.73+/-0.48 mm, 0.82+/-0.21 mm, and 0.97+/-0.09 mm for the surgical control group, the PLGA group, and the SSE/PLGA group, respectively, with no significant differences being observed among the treatments. The amount of new alveolar bone formation was 1.74+/-0.25 mm, 2.36+/-0.30 mm, and 2.64+/-0.74 mm for the surgical control group, the PLGA group, and the SSE/PLGA group, respectively, with a significant difference exhibited between the surgical control group and other groups (P <0.05). Superficial root resorption was often observed, but ankylosis was not present.

CONCLUSION

Our results suggest that surgical application of polylactide glycolic acid non-woven membrane with or without safflower seed extract could promote the regeneration of alveolar bone and cementum in intrabony periodontal defects.

A comparative study on the use of a HA/collagen/chondroitin sulphate biomaterial (Biostite) and a bovine-derived HA xenograft (Bio-Oss) in the treatment of deep intra-osseous defects

OBJECTIVES

This parallel-group, randomized, clinical trial was designed to evaluate the clinical outcome of deep intra-osseous defects following reconstructive surgery with the use of a synthetic hydroxyapatite/equine Type I collagen/chondroitin sulphate biomaterial (Biostite), as compared to a bovine-derived hydroxyapatite xenograft (Bio-Oss).

MATERIAL AND METHODS

Twenty-four systemically healthy subjects with moderate to advanced periodontitis, 11 females and 13 males, aged 30-64 years, seven smokers, were selected. Patients presented with one interproximal deep intra-osseous defect (intra-osseous component >or=4 mm) as clinically and radiographically evaluated. Immediately before surgery and 12 months after surgery, pocket probing depth (PPD), clinical attachment level (CAL) and radiographic depth of the defect (DEPTH) were evaluated.

RESULTS

Thirteen defects were treated with Biostite (test) and 11 defects with Bio-Oss (control). In the test group, PPD amounted to 7.8+/-1.3 mm before surgery, and decreased significantly to 3.6+/-1.6 mm 12 months following surgery, while in the control group PPD significantly decreased from 7.5+/-2.0 mm pre-surgery to 3.1+/-1.0 mm post-surgery. At 1 year, CAL gain and DEPTH gain were 2.9+/-1.9 and 2.5+/-1.4 mm, respectively, in the test group, and 4.0+/-2.4 mm and 3.1+/-1.8 mm, respectively, in the control group. No statistically significant differences for PPD reduction, CAL gain and DEPTH gain were detected between the groups.

CONCLUSIONS

The results of the present study indicate that both Biostite and Bio-Oss grafting biomaterials have determined a clinically and statistically significant improvement in terms of CAL gain, PPD reduction and radiographic DEPTH gain when used for the treatment of deep intra-osseous defects.

Eight-week histological analysis on the effect of chitosan on surgically created one-wall intrabony defects in beagle dogs

OBJECTIVE

To evaluate the periodontal tissue regenerative effects of a chitosan/collagen sponge applied to preclinical one-wall intrabony defects surgically created in beagle dogs.

MATERIAL AND METHODS

4 x 4 mm one-wall intrabony defects were surgically created in the bilateral maxillary first and third, and the mandibular second and fourth premolars. The surgical control group received a flap operation only, while the buffer control group was treated afterwards with a phosphate-buffered saline/collagen sponge (CS) and the chitosan group was treated with a chitosan/cs. The subjects were killed 8 weeks after the operation, and a comparative histological examination was performed.

RESULTS

The amount of junctional epithelium migration was 2.30+/-1.24 mm in the surgical control group, 1.49+/-1.25 mm in the buffer control group, and 0.26+/-0.59 mm in the chitosan group. A significant difference was exhibited only between the surgical control and the chitosan group (p<0.05). The amount of connective tissue adhesion was 0.68+/-0.60, 1.07+/-0.91, and 0.41+/-0.42 mm in the surgical control, buffer control, and the chitosan group, respectively. The amount of cementum regeneration was 1.42+/-0.49, 1.60+/-0.41, and 3.46+/-0.78 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was seen between the chitosan group and the rest (p<0.01). The amount of alveolar bone regeneration was 1.00+/-0.77, 1.52+/-0.37, and 2.43+/-0.44 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was observed between the chitosan group and the rest (p<0.05).

CONCLUSION

The results demonstrate the beneficial effect of the chitosan/cs on the one-wall intrabony defects of beagle dogs. The inhibited apical migration of epithelium and the increase in the amount of new bone and new cementum suggest the potency of chitosan in inducing periodontal tissue regeneration.

Defect-determined regenerative options for treating periodontal intrabony defects in baboons

BACKGROUND

In an effort to regenerate periodontal intrabony defects, the healing potential of the defect should determine what therapeutic modalities and materials are employed. The purpose of this study was to compare regenerative outcomes in baboon intrabony defects that were contained versus non-contained, using various regenerative therapies.

METHODS

Nine adult baboons (Papio anubis) in good health were treated. Eighty-six interproximal, intrabony defects were surgically created: 43 contained by 3 walls of bone; 43 non-contained with a missing buccal wall. Chronicity and plaque accumulation were encouraged with wire ligature placement for 8 weeks. After ligature removal, scaling, and a 2- to 4-week healing period, the defects were treated with the following therapies: collagen membrane (GTR), human demineralized freeze-dried bone (DFDB) grafting (BG), combined therapy (GTR + BG) and a DFDB-glycoprotein sponge matrix (MAT). Clinical healing responses were evaluated in 58 sites by changes in soft tissue (recession, probing, clinical attachment) and hard tissue (resorption, defect fill) parameters 6 months post-treatment. Histologic evaluation (defect regeneration, connective tissue attachment, epithelial migration) was done on 26 sites.

RESULTS

For contained defects, no real significant clinical (ANOVA) or histologic differences existed among treatments. However, for non-contained defects, combined therapy (GTR + BG) demonstrated clinically significant (P < or = 0.05, ANOVA) and histologically superior healing results over the other therapies tested.

CONCLUSION

These results confirm a defect morphology directed rationale for periodontal intrabony therapy.

Effect of surgical implantation of recombinant human bone morphogenetic protein-2 in a bioabsorbable collagen sponge or calcium phosphate putty carrier in intrabony periodontal defects in the baboon

BACKGROUND

Recombinant human bone morphogenetic protein-2 (rhBMP-2) in a proper carrier has been shown to induce clinically relevant bone formation for several oral/maxillofacial and periodontal indications and to stimulate regeneration of the periodontal attachment. The objective of this study is to evaluate regeneration of alveolar bone, cementum, periodontal ligament, and associated root resorption and ankylosis following surgical implantation of rhBMP-2 in an absorbable collagen sponge (ACS) or a calcium phosphate putty (alphaBSM) carrier in 3-wall intrabony periodontal defects in the baboon.

METHODS

rhBMP-2/ACS and rhBMP-2/alphaBSM were implanted in surgically produced, maxillary and mandibular, large size, 3-wall intrabony defects in 4 baboons. Contralateral jaw quadrants were implanted with buffer/ACS, buffer/ alphaBSM, or served as sham-operated surgical controls. Treatments were allocated to left and right, maxillary and mandibular, jaw quadrants following a randomization schedule. Four months following implantation, block biopsies of defect sites were obtained, processed, and subjected to histologic and histometric analysis.

RESULTS

Defect sites receiving rhBMP-2/ACS and rhBMP-2/alphaBSM demonstrated significantly greater regeneration than controls. No significant differences were observed between defect sites receiving rhBMP-2/ACS or rhBMP-2/alphaBSM regarding epithelial migration and connective tissue attachment and new bone formation. However, rhBMP-2/ACS supported significantly greater new cementum formation. Ankylosis or root resorption were not observed.

CONCLUSIONS

The results of this study support the use of rhBMP-2 to enhance periodontal regeneration of intrabony periodontal defects. While this novel technology holds promise, refinement in carrier systems may provide the key to enhancement of the regenerative potential.

The effect of safflower seed extract on periodontal healing of 1-wall intrabony defects in beagle dogs

BACKGROUND

Recent interest in naturally based products has increased. Various herbal extracts are known to have a variety of medicinal properties. Among the various natural medicines, safflower seeds have beneficial effects on various bone diseases such as bone fracture, osteoporosis, and osteodysplasia. In addition, they are known to have anti-inflammatory effects. The objective of this study was to evaluate the effect of a safflower seed extract (SSE) on the regeneration of periodontal tissue in a preclinical 1-wall model in dogs.

METHODS

Preclinical 1-wall periodontal defects were surgically created in the mesial aspect of the maxillary third and mandibular fourth premolar and in the distal aspect of the maxillary first and mandibular second premolar, and were randomly assigned to receive SSE/collagen (SSE/Col), phosphate-buffered saline/collagen (buffer control), or root planing only (surgical control). The created 1-wall defect configuration was 4 mm in depth by 4 mm in width. We selected the segment showing the best activity to the osteoblast cells that was sensitive to the formation of calcified nodules among the SSE fractions extracted from various organic solvents. The animals were euthanized at 8 weeks postsurgery, and block sections of the defects were collected for histologic and histometric analysis.

RESULTS

The junctional epithelium migration did not show any statistically significant differences among the treatments. In connective tissue adhesion, the SSE/Col group and the buffer control group showed significant differences compared to the surgical control group. New cementum averaged 3.84 +/- 0.57 mm, 3.75 +/- 0.24 mm, and 1.53 +/- 1.22 mm for the SSE/Col group, the buffer control group, and the surgical control group, respectively, with the SSE/Col and buffer control groups significantly different from the surgical control group (P < 0.05). The amount of intrabony cementum in the SSE/Col group was significantly different (P < 0.01) from the surgical control group, but the amount of suprabony cementum did not demonstrate any statistical difference between the different treatments. The amount of new alveolar bone averaged 2.93 +/- 0.70 mm, 2.10 +/- 0.63 mm, and 1.20 +/- 0.65 mm for the SSE/Col group, the buffer control group, and the surgical control group, respectively. The difference in alveolar bone regeneration between the SSE/Col group and the surgical control group was significantly different (P < 0.01). Root resorption was often observed, but no ankylosis was present.

CONCLUSION

Wound conditioning with safflower seed extracts may contribute to bone formation but appears to have unpredictable potential for stimulating periodontal regeneration including new cementum.

Preparation, characterization and in vitro release of gentamicin from coralline hydroxyapatite-gelatin composite microspheres

Composite microspheres have been prepared from bioactive ceramics such as coralline hydroxyapatite [CHA, Ca10(PO4)6(OH)2] granules, a biodegradable polymer, gelatin and an antibiotic, gentamicin. In our earlier work, we have shown a gentamicin release from CHA granules--chitosan composite microspheres. In the present investigation, an attempt was made to prepare the composite microspheres containing coralline hydroxyapatite and gelatin (CHA-G), which were prepared by the dispersion polymerization technique and the gentamicin was incorporated by the absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. The Fourier transformed infrared spectrum clearly indicated the presence of amide and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs show that the composite microspheres are spherical in shape and porous in nature. The particle size of composite microspheres was analyzed and the average size was found to be 16 microm. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns.

Influence of magnesium substitution on a collagen-apatite biomaterial on the production of a calcifying matrix by human osteoblasts

The induction of a calcifying matrix is of great interest in the restoration of bone defects. In a previous in vitro study we demonstrated that a collagen sponge constituted of type I collagen fibrils, chondroitin sulfates, and hydroxyapatite crystals induces an earlier and a more abundant synthesis of a new extracellular calcifying matrix than do other biomaterials such as collagen or hydroxyapatite alone. Bone mineral contains various amounts of magnesium ions, either adsorbed at the surface of apatite crystals or incorporated inside the crystal structure. Magnesium is known to reduce the degradation rate of tricalcium phosphate ceramics and to influence the crystallization of mineral substance. Thus we evaluated two sponges modified with different substituted apatites. The substituted low magnesium-containing apatite sample decreased the osteoinductive properties of the sponge whereas the substituted high magnesium-containing apatite sample had a toxic effect on bone cells and prevented the formation of any extracellular matrix. Such a toxic effect can be explained by the presence of large numbers of magnesium ions released into the culture medium even though at physiological level magnesium is able to promote bone mineralization and to control the growth of hydroxyapatite crystals. Thus collagen sponges containing hydroxyapatite remain one of the most appropriately evaluated biomaterials used for the restoration of periodontal pockets and bone defects.

Scintigraphic evaluation of healing response after heterograft usage for alveolar extraction cavity

OBJECTIVE

Reconstruction of bone defects remains an important problem in oral and maxillofacial surgery. Restoration of defect sites with various grafting materials is a valuable approach to the solution of this problem. The aim of this study was to evaluate the effects of the use of heterografts on osteoblastic activity by means of a radionuclide technique.

STUDY DESIGN

The postextraction alveolar cavities of impacted mandibular third molars on 22 patients were used as a healing model for this study. Granulated freeze-dried heterograft material of bovine origin was used on 11 patients; the other 11 patients constituted a control group. On each patient, three-phase bone scans were performed on postoperative days 7 and 28.

RESULTS

Although dynamic and blood pool studies showed similar patterns with respect to the mean values of asymmetry ratios of operation sites to the contralateral sides for the 7th- and 28th-day scans, static-phase bone scans revealed that healing response through osteoinduction was more prominent in the study group than in the control group. A significant increase in the mean value of the ratio from the first scan to the second was observed on static images in the study group (first scan, 1.6 +/- 0.2; second scan, 2.0 +/- 0.5; p < 0.05). However, the same ratio failed to show any significant change in the control group (first scan, 1.5 +/- 0.2; second scan, 1.5 +/- 0.3; p > 0.05).

CONCLUSION

Static-phase bone scintigraphy showed that when freeze-dried heterograft material is used to fill alveolar extraction cavities, it stimulates osteoblastic activity, which in turn leads to acceleration of the healing process and helps to maintain the linearity of bony structure. Moreover, radionuclide study can be used to evaluate the viability of freeze-dried heterografts in the 4th postoperative week, at which time no additional increase in perfusion resulting from surgical trauma was found in our series.

Combined collagen membrane and hydroxyapatite/collagen chondroitin-sulfate spacer placement in the treatment of 2-wall intrabony defects in chronic adult and rapidly progressive periodontitis patients

This study, confined to non-smokers, evaluated guided-tissue regeneration in deep 2-wall intrabony defects using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer in 43 adult periodontitis (AP) and 14 rapidly progressive periodontitis (RPP) patients, no more than 1 defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the biomaterials were well tolerated in all patients and PI and SBI were kept at a low level. Following therapy, there was a significant gain in PAL (4.2 mm for AP; 3 mm for RPP) and reduction in PPD (6.1 mm for AP; 4.7 mm for RPP) for both groups of patients (p < 0.05). A significantly greater gain in PAL and reduction in PPD were observed for AP compared to RPP patients (p < 0.05). The change in GML was not statistically different between groups (1.8 mm for AP; 1.6 mm for RPP). It is concluded that the combined use of a diphenylphosphorylazide-cross-linked bovine type-I collagen membrane, supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer, is beneficial in improving PAL and reducing PPD in 2-wall intrabony defects in both AP and RPP patients during the quiescent phase of the disease, with statistically better results for the former group. However, longer observation periods are necessary to evaluate the stability of the improvements obtained by this combined treatment approach between and for each group of patients.

Guided tissue regeneration in conjunction with hydroxyapatite-collagen grafts for intrabony defects. A clinical and radiological evaluation

This clinical and radiological study evaluated the healing of 3 + 2 + 1 wall-combined intrabony defects treated using the guided tissue regeneration technique (GTR) with and without hydroxyapatite-collagen alloplastic graft materials (HAC), in comparison to that of HAC alone and conventional flap surgery (CF). 40 interproximal defects with probing depth > 6 mm were treated in 18 adult periodontitis patients of ages 35-60 years. After non-surgical therapy, the defects were randomly grouped into 4 groups of 10 defects each. These groups were designated: (1) expanded polytetrafluoroethylene membrane (e-PTFE), (2) e-PTFE + HAC, (3) HAC alone and (4) CF. At 6 months, the following changes in parameters were recorded. Mean PPD reduction for each group was 5.83, 5.85, 3.80 and 3.17 mm respectively. PPD reduced very significantly in all groups (p < 0.01), the highest and lowest reductions in PPD being for the e-PTFE + HAC and CF group respectively. Comparison between the 4 groups showed higher PPD reduction in both membrane groups than in either of the non membrane groups (p < 0.05) with the difference between the e-PTFE and CF groups being very highly significant (p < 0.001). Mean attachment gain for the 4 groups was 3.70, 3.80, 2.60 and 2.1 mm, respectively. Similarly attachment gain for all groups was very significant (p < 0.01) and the highest and lowest attachment gains were for the e-PTFE + HAC and CF group respectively. Both membrane groups showed significantly more attachment gain than the CF group (p < 0.05). Change in probing bone level (BL) for the 4 groups was 1.60, 1.90, 1.0 and 0.65 mm respectively. Again the highest changes in BL were recorded for the e-PTFE + HAC group. Significant differences were found between both membrane groups and the CF group (p < 0.05). Radiological evaluation using standardized radiographs and millimeter grids showed change in radiographic bone level at the deepest point of the defect on the radiograph to be 1.50, 1.55, 0.85 and 0.60 mm, respectively and this was significantly higher in both membrane groups than in the CF group (p < 0.05). This study therefore found e-PTFE membranes both alone and when combined with HAC to lead to more attachment gain and bone fill than did HAC alone or CF. It found HAC combined with e-PTFE to perform better although not significantly better than e-PTFE alone.

Periodontal regeneration around natural teeth

1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

Healing response to anorganic bone implantation in periodontal intrabony defects in dogs. Part I. Bone regeneration. A microradiographic study

The purpose of the present study was to explore the regenerative potential of anorganic bone plus collagen (AB-C) in experimental intrabony defects. Eight healthy female beagle dogs, 3 to 4 years old and weighing 15 to 16 kilos, were used. After extraction of the mandibular third premolars (P3), surgical defects were created and inflammation induced by placement of cotton and steel braids. Eight weeks later, the braids were removed. The experimental lesions thus obtained were either treated by plain flap curettage (group 1: control) or were, in addition, implanted with AB-C (group 2: experimental). Blocks of AB-C alone were observed by scanning electron microscopy (SEM). The results show that the surface of the particles have the characteristics of a bone tissue. These particles are gathered together with a fibrillar network. Six, 18, and 36 weeks postoperative (PO), non-decalcified specimens from both groups were examined histologically by contact microradiography. In group 1, no significant bone regeneration was observed at 6, 18, or 36 weeks PO. In group 2, trabeculae undergoing mineralization and circumscribing dense particles above the reference notch were seen at 6 weeks PO; 18 and 36 week specimens showed significant bone regeneration with more or less dense remaining particles. The periodontal ligament space was always clear and the only signs of ankylosis noticed were deep in the notch on one 18 week group 2 specimen and on one 36 week group 1 specimen.

Collagen gel and membrane in guided tissue regeneration in periodontal fenestration defects in dogs

The effect of a collagen gel matrix as a submembranous space-maintaining material was evaluated in guided tissue regeneration procedures. In 4 dogs, contralateral surgical circular fenestration defects, 5 mm in diameter, were produced at the midbuccal aspect of the alveolar bone in 8 maxillary canines. Removal of bone, PDL and cementum was complete. Experimental sites were filled with collagen gel and covered with collagen membranes; control sites were covered with collagen membranes and the underlying space was spontaneously filled with blood. Mucogingival flaps were repositioned. Histological and histomorphometric observations, 6 weeks post-surgery, indicated that defects covered by collagen membranes presented the most impressive regeneration with almost complete coverage of the denuded root by new cementum (98.4%) and new bone (63.2%). In the experimental defects, 83.5% coverage of new cementum with only 21.9% new bone regeneration was observed. These results suggest that collagen gel, interfered with healing by PDL and bone-derived cells in the submembranous space.

Evaluation of a collagen membrane with and without bone grafts in treating periodontal intrabony defects

The aim of this study was to compare the clinical regenerative capacity of collagen membrane with and without demineralized freeze-dried bone allografts (DFDBA) in treating periodontal intrabony defects. Ten systemically healthy patients with similar bilateral periodontal defects were scheduled for surgery. Each patient had at least > or = 6 mm clinical probing depth and loss of attachment at selected sites. Baseline measurements included gingival index (GI), plaque index (PI), gingival recession (GR), clinical attachment level (CAL), probing depth (PD), and mobility. At the time of surgery, the defects were randomly assigned to either test (collagen membrane plus DFDBA) or control group (collagen membrane only). Stent to base of the defects, stent to crest bone, crest of bone to base of the defect, and width of the defects were recorded at the time of surgery and reentry. Eight patients returned after 6 months for reentry surgery. Statistical analysis with a paired t test was used to evaluate the treatment effect and comparison between test and control groups. In addition, a McNemar test was used to analyze the significance of GI, PI, and mobility at different times. The result of this study indicated that both the collagen plus DFDBA and the collagen alone treatment groups had a significant decrease of PD (3.4 +/- 0.4 and 3.2 +/- 0.4 mm), gain of CAL (2.3 +/- 0.5 and 2.0 +/- 0.4 mm), and defect fill (1.7 +/- 0.3 and 1.9 +/- 0.9 mm) (P < 0.05) when compared to the presurgery status. However, there was no significant difference in PD, AL, GR, defect fill, crestal bone resorption, GI, PI, or mobility between the test group and control group. No adverse tissue reaction, infection, or delayed wound healing was noted throughout the treatment in either group. This study suggests that the collagen membrane is well tolerated by the human tissues. Both treatments, either collagen membrane plus DFDBA or collagen membrane alone, promoted significant resolution of periodontal intrabony defects. The addition of a bone graft (DFDBA) with a collagen membrane appears to add no extra benefit to the collagen membrane treatment.

Extracellular matrix interactions during the in vivo degradation of collagen membranes in the rat skin: immunohistochemical distribution of collagen types IV, V, and VI

The role of collagen implant material (CIM) in periodontology is of considerable interest to the clinical dentist because of the capacity of connective tissue (CT) regeneration and partial prevention of epithelial cell migration onto the root surface. The aim of this study was to demonstrate alterations of the CT matrix after the use of CIM in subcutaneous pockets in the rat skin. We used 15 rats in this study. After sedation, two subcutaneous pockets (2 cm in length) were surgically made in the animals' backs. Collagen membranes were implanted in one of the two pockets (test site). The other pocket served as control. Then, 4, 7, 14, 21, and 28 days after implantation, the animals were sacrificed and biopsies preserved for histologic and immunohistochemical examination. Incubation with antibodies against CT matrix components (collagen type IV, V, and VI) were used for immunostaining. Histologically, the CIM was migrated by inflammatory cells in the first 7 days. Newly formed fibroblasts and blood vessels (BV) were present 14 days postimplantation. Collagen type IV was localized in the basement membranes of the epithelium, BV, and nerves. An increase in the BV amount was demonstrated around (and later in) the implant material. Collagen type V was found in a filament pattern of distribution and was inserted into the implant after 4 weeks of healing. Collagen type VI showed a microfibrillar pattern of distribution with a delayed formation in the graft mass. The data showed the alterations of the matrix after implantation of collagen type I membranes in the rat skin.(ABSTRACT TRUNCATED AT 250 WORDS)

A clinical comparison of collagen membranes with e-PTFE membranes in the treatment of human mandibular buccal class II furcation defects

Guided tissue regeneration procedures using non-resorbable expanded polytetrafluoroethylene (e-PTFE) membranes have become accepted therapy in treating moderate furcation defects. Resorbable collagen membranes have also been found to support regeneration and preclude the need for surgical removal. The present study compares their effectiveness with e-PTFE membranes in treating human mandibular Class II buccal furcation defects over a 12-month healing interval. Twelve patients were treated with collagen membrane in one defect and e-PTFE in another. Vertical and horizontal defect repair was evaluated through soft tissue probings and hard tissue measurements. Gingival indices and crevicular fluid flow measurements were used to evaluate site inflammation. Intragroup comparisons were made from baseline to 12 months for each type of membrane (sign test) and for differences between treatment groups with collagen versus e-PTFE membranes (Wilcoxon signed rank test). Both materials were effective in gaining vertical open probing new attachment and horizontal open and closed probing new attachment. Collagen membrane was statistically superior to e-PTFE in gaining horizontal open new probing attachment and in reduced levels of inflammation at the surgical site from baseline to 4 weeks. However, clinical differences were negligible. The intrinsic properties and ease of handling make collagen membranes a feasible alternative in guided tissue regeneration procedures.

Periodontal regeneration updated

Techniques in treating periodontal disease are discussed to provide insight about which technique fits each clinical situation. New developments provide possible regeneration of new cementum, periodontal ligament and alveolar bone, resulting in a new periodontal attachment.

Polymeric calcium phosphate cements: analysis of reaction products and properties

Chemical and mechanical properties of water-based polymeric calcium phosphate cements (PCPC) were investigated. These cements were derived from mixing several types of water-soluble polymers, e.g., gelatin, poly(vinyl alcohol) (PVA), and poly(alkenoic acids) such as poly(acrylic acid), with a calcium phosphate cement (CPC) mixture consisting of equimolar amounts of tetracalcium phosphate (TTCP) and anhydrous dicalcium phosphate (DCPA) as well as several other TTCP-containing mixtures. Cement formation was observed with all of the PCPCs. With the gelatin and PVA cements, significant amounts of hydroxyapatite (HA) formation were observed within 24 h. Their setting times and mechanical properties were similar to those of the purely inorganic CPC that is derived from the reaction of TTCP and DCPA in water. Although the mechanical properties of a gelatin-CPC cement were only slightly improved, its handling characteristics were superior to that of CPC. Significantly faster setting and stronger cements were obtained using polycarboxylic acid polymers with CPC. However, only small amounts of HA were observed in these types of polymeric cements even after 1 mon storage in distilled water at 37 degrees C. This research demonstrates the feasibility of preparing several new types of dental cements based on the interaction of water-soluble polymers with a self-setting calcium phosphate powder mixture.

In vitro induction of a calcifying matrix by biomaterials constituted of collagen and/or hydroxyapatite: an ultrastructural comparison of three types of biomaterials

The induction of a calcifying matrix was studied in vitro and compared for three biomaterials (collagen sponge, hydroxyapatite material and a mixture of both (Biostite)) cultured with human osteoblast-like cells. The influence of biomaterials on organic matrix synthesis and the calcification process was analysed at the ultrastructural level (transmission electron microscopy and X-ray microanalysis). Biomaterials were well tolerated by bone cells. Whichever biomaterial was used, osteoblasts proliferated and synthesized a new matrix constituted of fibrillar and non-fibrillar elements. This activity appeared earlier and was more intense with Biostite than with collagen sponge alone. A deposition of a mineral substance in this newly formed matrix was observed with the collagen sponge and Biostite, but never with hydroxyapatite alone. The mineral deposits were identified as hydroxyapatite crystals, similar to those observed and analysed in bone tissue. These in vitro observations clearly demonstrated the property of Biostite to produce a calcified collagenous matrix similar to bone tissue. However, in vivo confirmation is required before extending the use of this biomaterial to periodontology.

Feline experimental models for control of periodontal disease

Feline periodontal disease has many elements in common with human and canine disease. Anatomic, physiologic, microbiologic, and immunologic differences between the three species make it impossible to predict with certainty whether successful approaches to controlling and treating canine oral disease will also prove successful in cats. We have developed methods for reproducible, quantitative evaluation of feline dental plaque and calculus. Our studies demonstrated that feline plaque accumulation peaks at 1 week after prophylaxis and that calculus peaks at 4 weeks after prophylaxis. These methods should be adequately sensitive to document control of plaque and calculus accumulation by efficacious chemical or antimicrobial agents.

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.

Light and electron microscopic evaluation of biocompatibility, resorption and penetration characteristics of human collagen graft material

This study was initiated to test the biocompatibility, resorption and penetration characteristics of human collagen graft material in vitro and in vivo using light (LM) and electron microscopy (EM). To study this relationship, pieces of glutaraldehyde cross-linked collagen sponges (1 x 1 x 0.5 cm), were: (1) cultured in sterile Petri dishes with human gingival fibroblasts and human periodontal ligament fibroblasts for 2 weeks; (2) implanted in subcutaneous pockets made in both thighs (total 20 sites) of 10 Sprague-Dawley rats for 7-56 days. The behaviour of the growth of the fibroblasts was studied by inverted light microscopy (LM), then tissue culture specimens were studied from without and within using low-temperature scanning electron microscopy (LTSEM). Blocks obtained from the graft sites of the rat were processed for LM and transmission EM. Long-term LM observations showed attachment and random orientation of cells on and around the collagen sponge in culture during the first 48 h. Between 7 and 14 days, the majority of the cells adjacent to the sponge were orientated at right angles to its margin with their long axes approximately parallel to each other. The LTSEM revealed that large numbers of HGF and HPLF grew onto the collagen sponges, but no cellular penetration to the middle of the sponge was seen. LM and TEM of the rat specimens showed a cellular reaction to the collagen graft, as well as slow resorption, and fibroblast invasion of the graft at 6-8 weeks. It was concluded that the human collagen graft was biocompatible with HGF and HPLF, with penetration first observed at 42 days post-implantation. In the in vivo study, the collagen underwent slow resorption over a period of 8 weeks.

Periodontal healing following guided tissue regeneration with citric acid and fibronectin application

This study was undertaken to determine the effects of guided tissue regeneration (GTR) with and without citric acid conditioning and autologous fibronectin application. The study subjects were four female beagle dogs with spontaneous periodontitis. The dogs were given thorough root debridement and 4 weeks later, mucoperiosteal flaps were raised on both sides of the mandible involving the 2nd, 3rd, and 4th premolar and 1st molar teeth. After debridement, notches were placed on the roots at the level of supporting bone. Citric acid (pH 1) was topically applied for 3 minutes on the exposed root surfaces of one side (experimental). The roots were irrigated with normal saline solution. Both the root surfaces and the inner surface of the flap were then bathed in autologous fibronectin in saline. Following this, Gore-Tex periodontal material was adapted to the roots of each tooth and sutured. The contralateral side, serving as control, was treated by surgery and application of Gore-Tex periodontal material only. All membranes were removed 1 month after surgery, and the dogs sacrificed at 3 months. Both mesio-distal and bucco-lingual microscopic histological sections were evaluated by descriptive histology, and linear measurements and surface area determination of the furcal tissues were made. Periodontal healing following the use of GTR procedure resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive critic acid plus autologous fibronectin produced slightly better results, but these differences were not statistically significant for this sample.

The use of collagen membrane barriers in conjunction with combined demineralized bone-collagen gel implants in human infrabony defects

The present study evaluated the clinical efficacy of a combined graft of autolysed antigen-extracted allogeneic (AAA) bone and microfibrillar collagen (Zyderm) covered with a resorbable collagen membrane in human infrabony defects. The results were compared at 1 year with debrided controls, AAA bone grafts alone, combined AAA bone-collagen grafts (without membrane), and debrided defects covered only with collagen membranes. Ten adult patients having moderate periodontitis and one or more radiographically detectable angular defects probing 6 mm to 7 mm in each quadrant were included. Preoperative measurements of clinical attachment, probing depth, and recession were taken and compared at 1 year following surgery. Measurements at the time of surgery and at 1 year re-entry evaluated osseous defect fill and crestal changes. Each patient received the 5 treatment modalities. Treatment results per patient were used for a series of 2-way analyses of variance. When a significant difference was found, a Student-Newman-Keuls multiple range test was used to determine which treatments were statistically different (0.05 probability level) from each other. All treatment modalities showed improvement over the debrided controls. Similar advantages to using bone-collagen grafts with and without membranes were found in reducing probing depths and gaining new attachment. Significant differences were found when comparing the multifaceted bone graft collagen-membrane technique to all others in achieving superior defect fill. Ninety three percent of all defects treated resulted in 50% or greater fill.

Biphasic calcium phosphate ceramic combined with fibrillar collagen with and without citric acid conditioning in the treatment of periodontal osseous defects

The purpose of this study is to determine whether the combination of biphasic calcium phosphate ceramic (BCP) and collagen and citric acid root conditioning would promote accelerated new attachment of periodontal tissue to the root surface in dogs. Intrabony defects were surgically produced for each animal and were made chronic for 16 weeks. These defects were assigned to two study treatment and one control group: ceramic-collagen without citric acid (CO-CE); ceramic-collagen with citric acid (CO-CE-CA); and control (surgical debridement and root planing only). Results showed that all groups gained new attachment level as demonstrated both clinically and histometrically. The treatment groups showed a significant mean gain greater than the control (P less than .005), but no significant difference was found between treatment groups. Small areas of ankylosis was also found in both treatments but there was no evidence of active root resorption. It is concluded that the use of combined BCP and fibrillar collagen is beneficial in promoting new attachment of periodontal tissues to the root surface in dogs. Although citric acid root conditioning did as well or better than ceramic and collagen alone, its benefits are still speculative and need further experimentation.

The use of collagen membranes to guide regeneration of new connective tissue attachment in dogs

The aim of the present investigation was to evaluate the effectiveness of collagen membrane placement in excluding gingival epithelium and connective tissue cells and guiding new attachment in surgical treatment of created defects in dogs. Sixty defects were chosen at random and balanced in regard to receiving the following treatments: 1) untreated control, 2) debrided control, and 3) collagen membrane placement over the defect (along the root surface and under the replaced flap). Histologic and histometric evaluation at 2-12 weeks post-operatively determined the healing responses of each treatment modality. Epithelium migration with no new attachment occurred in the untreated and debrided areas. Collagen membrane placement was effective in inhibiting epithelial migration and encouraging formation of new connective tissue attachment to root surface previously altered by plaque.

Histological study of the hydroxyapatite-collagen complex implants in periodontal osseous defects in dogs

This study was performed to determine whether the process of wound healing, following periodontal surgery, could be improved through the combined use of collagen and grafting of hydroxyapatite (HAP) particles. Twenty-four proximal defects were made in the mandibular fourth premolars and second molars of six adult mongrel dogs. Steel wires and resin were put into the defect to enhance plaque formation. At eight weeks, the wires and resin were removed. At ten weeks, HAP or HAP-collagen complex was implanted during reconstructive surgery, along the root surface treated with acid conditioning. Dogs that received no implant following a flap operation served as controls. In these three groups of animals, differences in the extent and features of healing were histopathologically examined two months later. Animals implanted with a HAP-collagen complex showed a larger amount of new cementum formation when compared with HAP-implanted or control animals. In addition, in animals from the HAP-complex group, the interdigitation between the root surface and the gingival connective tissue fibers tended to be reinforced resulting in suppressed epithelial downgrowth. However, neither bone formation nor the reformation of the periodontium was promoted in the HAP-collagen complex group. These results suggest that implantation of an HAP-collagen complex promotes cemento-genesis of the demineralized root surface and can establish a stronger interdigitation between the root surface and the gingival connective tissue fibers.

The effect of supracrestal tricalcium phosphate ceramic-microfibrillar collagen grafting on postsurgical soft tissue levels

In this clinical study, a combined tricalcium phosphate ceramic (TCP) microfibrillar collagen supracrestal graft was used in conjunction with pocket elimination surgery as a soft tissue space filler to maintain marginal and interproximal tissue heights. Fifteen volunteer adult patients (8 male, 7 female) aged 37 to 48 years were selected. Standardized clinical probing measurements were used to evaluate soft tissue recession, clinical attachment, and probing pocket depths. Intraoral photographs and radiographs supplemented documentation. Twenty-five paired test and control sites were evaluated. Following flap surgery and minor osteoplasty, test defects received supracrestal grafts of TCP microfibrillar collagen prior to flap closure. Intrabony defects were excluded. Treatment modalities were compared by analyzing changes in clinical probing measurements over four months using the students t test for paired samples at the 0.01 level of significance. Supracrestal grafting resulted in 16.74% less soft tissue recession than the control sites. In addition, there was a significant gain in clinical attachment levels compared with the controls. All implanted sites demonstrated an advantage in the use of supracrestal TCP-collagen grafts compared with the controls. This treatment modality may have value in reducing esthetic deformities, food impaction areas, and root exposure that often occur following periodontal surgery.