Regenerative effect of basic fibroblast growth factor on periodontal healing in two-wall intrabony defects in dogs

Recombinant human fibroblast growth factor and autogenous bone for periodontal regeneration: Alone or in combination? A randomized clinical trial

AIM

To compare the outcomes of therapy using recombinant human fibroblast growth factor (rhFGF)-2 combined with autologous bone grafting (ABG) therapy with those of rhFGF-2 alone and ABG alone in the treatment of periodontal intraosseous defects.

METHODS

Periodontal intraosseous defects were randomized to receive rhFGF-2 therapy + ABG, rhFGF-2 therapy alone, or ABG alone. Periodontal examination and periapical radiography were performed preoperatively and at 3, 6, and 12 months postoperatively.

RESULTS

At the 12 months follow-up, all three groups showed significant improvement in the clinical attachment level (CAL): 5.6 ± 1.6, 5.8 ± 1.7, and 5.2 ± 1.6 mm in the rhFGF-2 + ABG, rhFGF-2 alone, and ABG alone groups, respectively, with no significant inter-group differences (p < .05). rhFGF-2 therapy (alone or in combination) resulted in greater bone defect filling (BDF) (2.3 ± 1.2 mm and 2.6 ± 1.9 mm, respectively) than ABG therapy alone (1.2 ± 1.2 mm). Gingival recession was lesser in the ABG alone (1.2 ± 1.1 mm) and rhFGF-2 + ABG groups (1.4 ± 0.8 mm) than in the rhFGF-2 alone group (2.2 ± 1.2 mm).

CONCLUSION

The results of this study showed that at 12 months postoperatively, all treatments resulted in statistically significant clinical improvements compared to the baseline. From these results, it can be concluded that rhFGF-2 promotes hard tissue regeneration in intraosseous defects.

Use of Melatonin/Decorticotomy and Autogenous Bone Graft in Induced 1-Wall Defect

PURPOSE

This study was designed to investigate the effect of intramarrow penetration (IMP) and 1% melatonin (MLN) gel on the remodelling process of autogenous bone graft (ABG) in an induced 1-osseous wall defect model.

METHODS

Sixty-four intrabony induced mandibular defects were created on the distal side of premolars-P1, P2, P3, and P4 (on each side)-in 8 beagle dogs. A ligature-induced periodontitis was initiated in each defect. Defects were then divided into 4 equal groups. Group I was treated with open-flap debridement (OFD) alone, group II was treated with OFD/ABG, group III was treated with OFD/IMP/ABG, and group IV was treated with OFD/ABG/IMP/1% MLN gel. The study parameters were bone fill, histologic analysis, and immunohistochemical evaluation of endothelial nitric oxide synthase (eNOS) expression at 2-week (2W) and 8-week (8W) time intervals.

RESULTS

At 8W, significant differences were revealed amongst all groups regarding the amount of bone fill and eNOS expressions (P < .001). Bone fill percentages were 55.5%, 22.3%, 16.8%, and 0% in groups IV, III, II, and I, respectively. eNOS expressions were 1.68 ± 0.06, 8.43 ± 0.04, 16.80 ± 0.17, and 1.97 ± 0.07 in groups IV, III, II, and I, respectively. The favourable results were in line with group IV.

CONCLUSIONS

According to these preliminary results, defects treated by ABG augmented with IMP and 1% MLN gel revealed a greater amount of bone fill and reduced eNOS expression. This combination is therefore highly suggested as an adjunct to ABG.

Histologic Evidence of Oral and Periodontal Regeneration Using Recombinant Human Platelet-Derived Growth Factor

Human histology provides critical information on the biological potential of various regenerative protocols and biomaterials, which is vital to advancing the field of periodontal regeneration, both in research and clinical practice. Outcomes of histologic studies are particularly valuable when interpreted considering additional evidence available from pre-clinical and clinical studies. One of the best-documented growth factors areproven to have positive effects on a myriad of oral regenerative procedures is recombinant human platelet-derived growth factor—BB (rhPDGF-BB). While a systematic review of clinical studies evaluating rhPDGF in oral regenerative procedures has been recently completed, a review article that focuses on the histologic outcomes is needed. Hence, this communication discusses the histologic effects of rhPDGF-BB on oral and periodontal regenerative procedures, including root coverage and soft tissue augmentation, intrabony defects, furcation defects, peri-implant bone augmentation, and guided bone regeneration. Studies from 1989 to 2022 have been included in this review.

Comparison of periodontal wound healing/regeneration by recombinant human fibroblast growth factor-2 combined with β-tricalcium phosphate, carbonate apatite, or deproteinized bovine bone mineral in a canine one-wall intra-bony defect model

AIM

To evaluate periodontal wound healing/regeneration of one-wall intra-bony defects treated with recombinant human fibroblast growth factor-2 (rhFGF-2) and beta-tricalcium phosphate (β-TCP), carbonate apatite (CO₃ Ap), or deproteinized bovine bone mineral (DBBM) in dogs.

MATERIALS AND METHODS

The stability of rhFGF-2 adsorbed onto the bone substitutes was evaluated by Enzyme-Linked Immunosorbent Assay (ELISA). One-wall intra-bony defects (5 × 5 × 5 mm) created in five adult male beagle dogs were treated with rhFGF-2 alone (rhFGF-2), rhFGF-2 with β-TCP (rhFGF-2/β-TCP), rhFGF-2 with CO₃ Ap (rhFGF-2/CO₃ Ap), or rhFGF-2 with DBBM (rhFGF-2/DBBM). Histological outcomes (e.g., linear length of new cementum adjacent to the newly formed bone with inserting collagen fibres [NA] as the primary outcome) were evaluated at 10 weeks post surgery.

RESULTS

Significantly higher amount of rhFGF-2 was adsorbed onto CO₃ Ap compared with β-TCP. Among the treatment groups, the rhFGF-2/DBBM group showed the highest amount of periodontal tissue regeneration. The rhFGF-2/DBBM group showed significantly greater formation of NA (3.22 ± 0.40 mm) compared with rhFGF-2 (1.17 ± 1.00 mm, p < .01) group. Additionally, new bone area in the rhFGF-2/DBBM group (9.78 ± 2.30 mm² ) was significantly higher than that in the rhFGF-2 (5.08 ± 1.26 mm² , p < .01), rhFGF-2/β-TCP (5.91 ± 1.27 mm² , p < .05), and rhFGF-2/CO₃ Ap (6.51 ± 1.49 mm² , p < .05) groups. Slight ankylosis was found in the rhFGF-2/β-TCP (1/9 sites), rhFGF-2/CO₃ Ap (3/10 sites), and rhFGF-2/DBBM (1/9 sites) groups.

CONCLUSIONS

Within their limitations, the present data indicate that DBBM seems to be a suitable carrier for rhFGF-2 and that rhFGF-2/DBBM treatment promotes favourable periodontal regeneration compared with rhFGF-2, rhFGF-2/β-TCP, and rhFGF-2/CO₃ Ap treatments in one-wall intra-bony defects.

A Review of Tissue Engineering for Periodontal Tissue Regeneration

Periodontal disease is one of the most common diagnoses in small animal veterinary medicine. This infectious disease of the periodontium is characterized by the inflammation and destruction of the supporting structures of teeth, including periodontal ligament, cementum, and alveolar bone. Traditional periodontal repair techniques make use of open flap debridement, application of graft materials, and membranes to prevent epithelial downgrowth and formation of a long junctional epithelium, which inhibits regeneration and true healing. These techniques have variable efficacy and are made more challenging in veterinary patients due to the cost of treatment for clients, need for anesthesia for surgery and reevaluation, and difficulty in performing necessary diligent home care to maintain oral health. Tissue engineering focuses on methods to regenerate the periodontal apparatus and not simply to repair the tissue, with the possibility of restoring normal physiological functions and health to a previously diseased site. This paper examines tissue engineering applications in periodontal disease by discussing experimental studies that focus on dogs and other animal species where it could potentially be applied in veterinary medicine. The main areas of focus of tissue engineering are discussed, including scaffolds, signaling molecules, stem cells, and gene therapy. To date, although outcomes can still be unpredictable, tissue engineering has been proven to successfully regenerate lost periodontal tissues and this new possibility for treating veterinary patients is discussed.

Visual and histological evaluation of the effects of trafermin in a dog oronasal fistula model

The standard procedure to treat oronasal fistula in dogs requires tooth extraction to close the fistula; hence, the subject would lose its tooth. In this study, trafermin was applied to four dog models with oronasal fistula to investigate the periodontal tissue regenerative effects of trafermin in the treatment without tooth extraction. A fistula was created along the palatal side of each upper canine tooth. One of the fistulae was filled with trafermin, whereas that on the contralateral side was left unfilled as a control. The results showed a significant decrease in the non-calcified periodontal tissue volume on the trafermin side after the fourth week. In addition, oronasal fistula closure was visually and histologically confirmed at the eighth week on the trafermin side of all four models.

Treatment of intrabony periodontal defects in controlled diabetic patients with an enamel matrix derivative: a split-mouth randomized clinical trial

OBJECTIVE

This split-mouth randomized controlled trial aimed to evaluate the effect of enamel matrix derivative (EMD) associated with a simplified papilla preservation flap (SPPF) compared to SPPF alone in the surgical treatment of intrabony defects (ID) in type 2 diabetic mellitus (T2DM) patients.

MATERIAL AND METHODS

Thirteen patients with controlled T2DM presenting with ID in at least two quadrants were included. In each patient, the test site (TS) was treated with SPPF plus EMD, whereas the control site (CS) was treated only with SPPF. Prior to surgery and at 6 months after intervention, the following parameters were evaluated: clinical attachment level (CAL), probing pocket depth (PPD), and gingival recession (GR).

RESULTS

The TS and CS demonstrated a mean CAL gain of 3.31 ± 0.96 mm and 1.61 ± 1.12 mm, and a PPD reduction from 8.15 ± 0.98 to 3.00 ± 0.57 mm and 7.53 ± 0.96 to 4.69 ± 0.63 mm after 6 months, respectively. In both sites, the mean CAL gain and PPD reduction improved significantly after 6 months compared to baseline; however, the improvement was higher in the TS (p < 0.001).

CONCLUSIONS

Both surgical procedures presented with clinical improvements in controlled T2DM patients. However, the additional use of EMD showed enhanced clinical results after 6 months with regard to CAL gain and PPD reduction.

CLINICAL RELEVANCE

This study showed a better PPD reduction and CAL gain when an EMD was applied in addition to SPPF. Therefore, EMD may be used to enhance clinical outcomes in periodontal ID of controlled T2DM patients.

Recombinant factors for periodontal intrabony defects: A systematic review and network meta-analysis of preclinical studies

The use of bioactive agents combined with osteoconductive scaffolds for the regeneration of periodontal intrabony defects has been the subject of intensive research in the past 20 years. Most studies reported that such agents, used in different concentrations, doses and combined with various scaffolds, might promote periodontal tissue regeneration, but evidence for the most effective combination of such agents is lacking. The objective of this study 13 was to rank the different combinations of recombinant human-derived growth and differentiation factors with/without scaffold biomaterial in the treatment of periodontal intrabony defects, through network meta-analysis of pre-clinical studies. The systematic review and network meta-analysis protocol was registered on the PROSPERO Systematic Review database with reference number: CRD42021213673. Relevant published articles were obtained after searching five electronic databases. A specific search strategy was followed by using keywords related to intrabony defects, regenerative materials, scaffolds and recombinant factors, and animal studies. All pre-clinical studies used for periodontal regeneration were included. The primary outcomes were: regeneration of junctional epithelium (mm), new cementum, connective tissue attachment, percentage of new bone formation (%), bone area (mm² ), bone volume density (g/cm³ ) and bone height (mm) data was extracted. The analysis was carried out using network meta-analysis methods, that is illustrating network plots, contribution plots, predictive and confidence interval plot, surface under the cumulative ranking (SUCRA), multidimensional scale ranking and net funnel plots using STATA IC statistical software. An SYRCLE's tool for assessing risk of bias was used for reporting risk of bias among individual studies. A total of N = 24 for qualitative and N = 21 studies for quantitative analysis published till 2020 were included. The cumulative total number of animals included in the control and test groups were N = 162 and N = 339, respectively. The duration of the study was between 3 and 102 weeks rhBMP-2 ranked higher in SUCRA as the agent associated with the best performance for bone volume density. rhGDF-5/TCP ranked best in the bone area (mm2), rhPDGF-BB/Equine ranked best in bone height (mm), rhBMP-2 ranked best in the percentage of new bone fill, rhBMP-2/ACS ranked best in new cementum formation, and rhGDF-5/b- TCP/PLGA ranked best in connective tissue attachment and junctional epithelium. There were no adverse effects identified in the literature that could affect the different outcomes for regeneration in intrabony defects. Various recombinant factors are effective in promoting the regeneration of both soft and hard tissue supporting structures of the periodontium. However, when considering different outcomes, different agents, associated or not with biomaterials, ranked best. Keeping into account the limited transferability of results from animal studies to the clinical setting, the choice of the most appropriate formulation of bioactive agents may depend on clinical needs and purpose.

Regenerative benefits of using growth factors in treatment of periodontal defects: A systematic review and meta-analysis with Trial Sequential Analysis on preclinical studies

The ultimate goal in periodontal treatments is to achieve a functional and anatomical regeneration of the lost tissues. Numerous studies have in some way illustrated the beneficial effects of biologic modifiers in this process, yet they are subject to a rather large degree of diversity in their results. Thanks to the promising outcomes of bioengineering techniques in the field of periodontal regeneration, this systematic review aims to evaluate the effect of various biologic modifiers used in periodontal defects of animal models. Electronic databases (Medline, Scopus, Embase, Web of Science, and Google Scholar) were searched (March 2010-December 2020) for every study that used biomolecules for regeneration of periodontal osseous defects in animal models. Regenerated bone height or area, new cementum, new connective tissues, new regenerated periodontal ligament and the dimensions of epithelial attachment (either in mm/mm² or percentage) were the investigated outcomes. The risk of bias of the included studies was assessed using the SYRCLE tool. In closing, there was a meta-analysis carried out on the outcomes of interest. Trial Sequential Analysis was also carried out to figure out the power of meta-analytic outcomes. From 1995 studies which were found in the initial search, 34 studies were included in this review, and 20 of them were selected for the meta-analysis. The eligible studies were categorized according to the morphology of the experimental periodontal defects as one-, two-, and three-wall intrabony defects; furcation defects, and recession-type defects. The most studied biomolecules were rhFGF-2, rhGDF-5, platelet-derived growth factor, bone morphogenetic protein-2, and enamel matrix derivative (EMD). Based on the meta-analysis findings, combined application of biomolecules with regenerative treatments could improve new bone and cementum formation near 1 mm when compared to the control groups in one, two and three-wall intrabony defect models (p < 0.001). In furcation grade II defect, the addition of biomolecules was observed to enhance bone area gain and cementum height regeneration up to almost 2 mm (p < 0.001). Trial Sequential Analysis results confirmed the significant effect in the aforementioned meta-analyses. In cases of the buccal recession model, the application of rhFGF-2 and rhGDF-5 decreased the dimension of epithelial attachments besides regenerative advantages on bone and cementum formation, but EMD deposition exerted no inhibitory effect on epithelial down-growth. Application of biologic modifiers especially FGF-2 and GDF-5, could positively improve the regeneration of periodontal tissues, particularly cementum and bone in animal models. Trial Sequential Analysis confirmed the results but the power of the evidences was high just in some subgroup meta-analyses, like bone and cementum regeneration in furcation grade II model and cementum regeneration in one-wall intrabony defects. The outcomes of this study can potentially endow clinicians with guidelines for the appropriate application of growth factors in periodontal regenerative therapies.

Periodontal tissue regeneration after low-intensity pulsed ultrasound stimulation with or without intra-marrow perforation in two-wall intra-bony defects-A pilot study in dogs

AIM

To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) with/without intra-marrow perforation (IMP) on periodontal healing in two-wall intra-bony defects in dogs.

MATERIALS AND METHODS

Two-wall intra-bony defects (5 mm wide, 5 mm deep) were created at the distal and mesial aspects of mandibular premolars in four beagle dogs (four defects per dog). The 16 defects were divided into four treatment groups: IMP, LIPUS, IMP + LIPUS (IMP/LIPUS) and control (open flap debridement). The LIPUS and IMP/LIPUS sites received daily LIPUS exposure for 3 weeks starting 1 week after surgery. The animals were euthanized 4 weeks after surgery for histologic evaluation.

RESULTS

There was significantly greater new bone formation at LIPUS (2.93 ± 0.74 mm) and IMP/LIPUS (3.18 ± 0.52 mm) sites than at control sites (1.65 ± 0.46 mm). New bone area at LIPUS (6.36 ± 2.28 mm² ) and IMP/LIPUS (6.13 ± 1.25 mm² ) sites was significantly greater than that at control sites (2.15 ± 1.75 mm² ). New cementum length at LIPUS sites (4.09 ± 0.75 mm) was significantly greater than that at control (2.29 ± 1.02 mm) and IMP (2.41 ± 0.41 mm) sites. No significant difference was observed between LIPUS and IMP/LIPUS sites in any histomorphometric parameter.

CONCLUSIONS

These findings suggest that LIPUS effectively promotes periodontal regeneration in two-wall intra-bony defects in dogs.

Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs

OBJECTIVES

The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs.

MATERIALS AND METHODS

Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation.

RESULTS

Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05).

CONCLUSION

Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects.

CLINICAL RELEVANCE

The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

Healing of two-wall intra-bony defects treated with a novel EMD-liquid-A pre-clinical study in monkeys

AIM

To investigate the effect of a novel enamel matrix derivative formulation (EMD-liquid or Osteogain) combined with an absorbable collagen sponge (ACS) on periodontal wound healing in intra-bony defects in monkeys.

MATERIALS AND METHODS

Chronic two-wall intra-bony defects were created at the distal aspect of eight teeth in three monkeys (Macaca fascicularis). The 24 defects were randomly assigned to one of the following treatments: (i) open flap debridement (OFD) + ACS alone, (ii) OFD + Emdogain + ACS (Emdogain/ACS), (iii) OFD + Osteogain + ACS (Osteogain/ACS) or (iv) OFD alone. At 4 months, the animals were euthanized for histologic evaluation.

RESULTS

Osteogain/ACS resulted in more consistent formation of cementum, periodontal ligament and bone with limited epithelial proliferation compared to OFD alone, Emdogain/ACS and OFD + ACS. Among the four treatment groups, the Osteogain/ACS group demonstrated the highest amount of regenerated tissues. However, complete periodontal regeneration was not observed in any of the defects in the four groups.

CONCLUSIONS

The present findings indicate that in two-wall intra-bony defects, reconstructive surgery with Osteogain/ACS appears to be a promising novel approach for facilitating periodontal wound healing/regeneration, thus warranting further clinical testing.

Tri-Layered Nanocomposite Hydrogel Scaffold for the Concurrent Regeneration of Cementum, Periodontal Ligament, and Alveolar Bone

A tri-layered scaffolding approach is adopted for the complete and concurrent regeneration of hard tissues-cementum and alveolar bone-and soft tissue-the periodontal ligament (PDL)-at a periodontal defect site. The porous tri-layered nanocomposite hydrogel scaffold is composed of chitin-poly(lactic-co-glycolic acid) (PLGA)/nanobioactive glass ceramic (nBGC)/cementum protein 1 as the cementum layer, chitin-PLGA/fibroblast growth factor 2 as the PDL layer, and chitin-PLGA/nBGC/platelet-rich plasma derived growth factors as the alveolar bone layer. The tri-layered nanocomposite hydrogel scaffold is cytocompatible and favored cementogenic, fibrogenic, and osteogenic differentiation of human dental follicle stem cells. In vivo, tri-layered nanocomposite hydrogel scaffold with/without growth factors is implanted into rabbit maxillary periodontal defects and compared with the controls at 1 and 3 months postoperatively. The tri-layered nanocomposite hydrogel scaffold with growth factors demonstrates complete defect closure and healing with new cancellous-like tissue formation on microcomputed tomography analysis. Histological and immunohistochemical analyses further confirm the formation of new cementum, fibrous PDL, and alveolar bone with well-defined bony trabeculae in comparison to the other three groups. In conclusion, the tri-layered nanocomposite hydrogel scaffold with growth factors can serve as an alternative regenerative approach to achieve simultaneous and complete periodontal regeneration.

Biodegradable gelatin/beta-tricalcium phosphate sponges incorporating recombinant human fibroblast growth factor-2 for treatment of recession-type defects: A split-mouth study in dogs

BACKGROUND AND OBJECTIVE

Tissue engineering by using recombinant human (rh) growth factor technology may offer a promising therapeutic approach for treatment of gingival recession. Fibroblast growth factor-2 (FGF-2) has shown the ability to promote periodontal regeneration. Gelatin/beta-tricalcium phosphate (gelatin/β-TCP) sponges have been developed to control the release of growth factors. The present study evaluated the periodontal regenerative efficacy of rhFGF-2 by comparing gelatin/β-TCP sponges incorporated with rhFGF-2 to the scaffolds alone in artificially created recession-type defects in dogs.

MATERIAL AND METHODS

Critically sized buccal gingival recession defects were surgically created on maxillary canine teeth of five dogs. In each animal, defects were randomized to receive either a gelatin/β-TCP sponge soaked with rhFGF-2 (gelatin/β-TCP/rhFGF-2) or phosphate-buffered saline (gelatin/β-TCP). Eight weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography and histological analyses.

RESULTS

Complete root coverage was achieved in both groups. Microcomputed tomography revealed significantly greater new bone volume in the gelatin/β-TCP/rhFGF-2 group. Histologically, both groups achieved periodontal regeneration; however, gelatin/β-TCP/rhFGF-2 sites exhibited more tissue regeneration, characterized by significantly larger amounts of new cementum and new bone. Gelatin/β-TCP sites featured increased long junctional epithelium and connective tissue attachment. In the gelatin/β-TCP/rhFGF-2 sites, new bone exhibited many haversian canals and circumferential lamellae as well as remarkably thick periosteum with blood vascularization and hypercellularity.

CONCLUSION

Within the limitations of this study, rhFGF-2 in gelatin/β-TCP sponges exhibits an increased potential to support periodontal wound healing/regeneration in canine recession-type defects.

Comparison of Different Periodontal Healing of Critical Size Noncontained and Contained Intrabony Defects in Beagles

BACKGROUND

Regenerative techniques help promote the formation of new attachment and bone filling in periodontal defects. However, the dimensions of intraosseous defects are a key determinant of periodontal regeneration outcomes. In this study, we evaluated the efficacy of use of anorganic bovine bone (ABB) graft in combination with collagen membrane (CM), to facilitate healing of noncontained (1-wall) and contained (3-wall) critical size periodontal defects.

METHODS

The study began on March 2013, and was completed on May 2014. One-wall (7 mm × 4 mm) and 3-wall (5 mm × 4 mm) intrabony periodontal defects were surgically created bilaterally in the mandibular third premolars and first molars in eight beagles. The defects were treated with ABB in combination with CM (ABB + CM group) or open flap debridement (OFD group). The animals were euthanized at 8-week postsurgery for histological analysis. Two independent Student's t-tests (1-wall [ABB + CM] vs. 1-wall [OFD] and 3-wall [ABB + CM] vs. 3-wall [OFD]) were used to assess between-group differences.

RESULTS

The mean new bone height in both 1- and 3-wall intrabony defects in the ABB + CM group was significantly greater than that in the OFD group (1-wall: 4.99 ± 0.70 mm vs. 3.01 ± 0.37 mm, P < 0.05; 3-wall: 3.11 ± 0.59 mm vs. 2.08 ± 0.24 mm, P < 0.05). The mean new cementum in 1-wall intrabony defects in the ABB + CM group was significantly greater than that in their counterparts in the OFD group (5.08 ± 0.68 mm vs. 1.16 ± 0.38 mm; P < 0.05). Likewise, only the 1-wall intrabony defect model showed a significant difference with respect to junctional epithelium between ABB + CM and OFD groups (0.67 ± 0.23 mm vs. 1.12 ± 0.28 mm, P < 0.05).

CONCLUSIONS

One-wall intrabony defects treated with ABB and CM did not show less periodontal regeneration than that in 3-wall intrabony defect. The noncontained 1-wall intrabony defect might be a more discriminative defect model for further research into periodontal regeneration.

Long-term Observation of Regenerated Periodontium Induced by FGF-2 in the Beagle Dog 2-Wall Periodontal Defect Model

The long-term stability and qualitative characteristics of periodontium regenerated by FGF-2 treatment were compared with normal physiological healing tissue controls in a Beagle dog 2-wall periodontal defect model 13 months after treatment by assessing tissue histology and three-dimensional microstructure using micro-computed tomography (μCT). After FGF-2 (0.3%) or vehicle treatment at the defect sites, serial changes in the bone mineral content (BMC) were observed using periodic X-ray imaging. Tissues were harvested at 13 months, evaluated histomorphometrically, and the cortical bone volume and trabecular bone structure of the newly formed bone were analyzed using μCT. FGF-2 significantly increased the BMC of the defect area at 2 months compared with that of the control group, and this difference was unchanged through 13 months. The cortical bone volume was significantly increased by FGF-2, but there was no difference between the groups in trabecular bone structure. Bone maturation was occurring in both groups because of the lower cortical volume and denser trabecular bone than what is found in intact bone. FGF-2 also increased the area of newly formed bone as assessed histomorphometrically, but the ratios of trabecular bone in the defect area were similar between the control and FGF-2 groups. These results suggest that FGF-2 stimulates neogenesis of alveolar bone that is of similar quality to that of the control group. The lengths of the regenerated periodontal ligament and cementum, measured as the distance from the defect bottom to the apical end of the gingival epithelium, and height and area of the newly formed bone in the FGF-2 group were larger than those in the control group. The present study demonstrated that, within the limitation of artificial periodontal defect model, the periodontal tissue regenerated by FGF-2 was maintained for 13 months after treatment and was qualitatively equivalent to that generated through the physiological healing process.

A Randomized Clinical Trial Evaluating rh-FGF-2/β-TCP in Periodontal Defects

Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a β-tricalcium phosphate (β-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups—β-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with β-TCP—following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/β-TCP groups with significant improvements over control and 0.1% rh-FGF-2/β-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/β-TCP ( ClinicalTrials.gov NCT01728844).

Ethical guidelines, animal profile, various animal models used in periodontal research with alternatives and future perspectives

Laboratory animal models serve as a facilitator to investigate the etiopathogenesis of periodontal disease, are used to know the efficacy of reconstructive and regenerative procedures, and are also helpful in evaluation of newer therapeutic techniques including laser and implant therapies prior to application in the human beings. The aim of this review is to know the different animal models used in various specialties of dental research and to know the ethical guidelines prior to the usage of experimental models with main emphasis on how to refine, replace, and reduce the number of animal models usage in the laboratory. An online search for experimental animal models used in dental research was performed using MEDLINE/PubMed database. Publications from 2009 to May 2013 in the specialty of periodontics were included in writing this review. A total of 652 references were published in PubMed/MEDLINE databases based on the search terms used. Out of 245 studies, 241 were related to the periodontal research published in English from 2009 to 2013. Relevant papers were chosen according to the inclusion and exclusion criteria. After extensive electronic and hand search on animal models, it has been observed that various animal models were used in dental research. Search on animal models used for dental research purpose revealed that various animals such as rats, mice, guinea pigs, rabbit, beagle dogs, goats, and nonhuman primates were extensively used. However, with the new advancement of ex vivo animal models, it has become easy to investigate disease pathogenesis and to test the efficacy of newer therapeutic modalities with the reduced usage of animal models. This review summarized the large amount of literature on animal models used in periodontal research with main emphasis on ethical guidelines and on reducing the animal model usage in future perspective.

Healing of localized gingival recessions treated with a coronally advanced flap alone or combined with an enamel matrix derivative and a porcine acellular dermal matrix: a preclinical study

OBJECTIVE

This study aimed to evaluate the effects of a porcine acellular dermal matrix (PADM) with or without an enamel matrix derivative (EMD) on gingival recession defects treated with a coronally advanced flap (CAF) in dogs.

MATERIALS AND METHODS

Miller class II gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 12 dogs. After 8 weeks of plaque accumulation, the 24 chronic defects were randomly assigned to one of the following 4 treatments: CAF, CAF with PADM (CAF/PADM), CAF with EMD (CAF/EMD), and CAF with EMD and PADM (CAF/EMD/PADM). The animals were sacrificed 10 weeks after surgery for histologic evaluation.

RESULTS

In all groups, root coverage was obtained to a varying degree. PADM was well incorporated in gingival connective tissue in the CAF/PADM and in the CAF/EMD/PADM groups. The height of newly formed bone was significantly greater in the CAF/EMD/PADM group than in the CAF and CAF/PADM groups. New cementum with periodontal ligament-like tissue was predominantly found in the CAF/EMD and CAF/EMD/PADM groups. The CAF/EMD/PADM group showed the greatest amount of new cementum among the groups examined, although the difference was not statistically significant.

CONCLUSION

Within the limitations of the present study, it can be concluded that CAF/EMD/PADM treatment may promote periodontal regeneration in gingival recession defects.

CLINICAL RELEVANCE

The present results suggest that the combination of EMD and PADM in conjunction with CAF may represent a promising approach for treating single Miller class II gingival recessions.

A comparative clinico-radiographic study of guided tissue regeneration with bioresorbable membrane and a composite synthetic bone graft for the treatment of periodontal osseous defects

Aim:

The aim was to evaluate the bonefill in periodontal osseous defects with the help of guided tissue regeneration, bioresorbable membrane (PerioCol) + bone graft (Grabio Glascera) in combination and with bonegraft (Grabio Glascera) alone.

Materials and Methods:

The study involved total 30 sites in systemically healthy 19 patients. The parameters for evaluation includes plaque index sulcus bleeding index with one or more periodontal osseous defects having (i) probing depth (PD) of ≥ 5 mm (ii) clinical attachment loss (CAL) of ≥ 5 mm and (iii) ≥3 mm of radiographic periodontal osseous defect (iv) bonefill (v) crestal bone loss (vi) defect resolution. The study involved the three wall and two wall defects which should be either located interproximally or involving the furcation area. The statistical analysis was done using Statistical Package for Social Sciences, the Wilcoxon signed rank statistic W + for Mann–Whitney U-test.

Results:

The net gain in PD and CAL after 6 months for Group I ([PerioCol] + [Grabio Glascera]) and Group II (Grabio Glascera) was 3.94 ± 1.81 mm, 3.57 ± 2.21 mm and 3.94 ± 1.81, 3.57 ± 2.21 mm, respectively. The results of the study for Group I and Group II with regards to mean net bonefill, was 3.25 ± 2.32 (58%) mm and 5.14 ± 3.84 (40.26 ± 19.14%) mm, crestal bone loss − 0.25 ± 0.68 mm and − 0.79 ± 1.19 mm. Defect resolution 3.50 ± 2.34 mm and 5.93 ± 4.01 mm, respectively.

Conclusion:

On comparing both the groups together after 6 months of therapy, the results were equally effective for combination of graft and membrane versus bone graft alone since no statistical significant difference was seen between above parameters for both the groups. Thus, both the treatment modalities are comparable and equally effective.

Application of coenzyme Q10 for accelerating soft tissue wound healing after tooth extraction in rats

Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10), may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old) (n = 27) received topical application of ointment containing 5% rCoQ10 (experimental group) or control ointment (control group) to the sockets for 3 or 8 days (n = 6–7/group). At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p < 0.05). Gene expression of interleukin-1β, tumor necrosis factor-α and nuclear factor-κB were also lower in the experimental group than in the control group (p < 0.05). At 8 days after tooth extraction, there were no significant differences in collagen density, number of polymorphonuclear leukocytes and bone fill between the groups. Our results suggest that topical application of rCoQ10 promotes wound healing in the soft tissue of the alveolar socket, but that rCoQ10 has a limited effect on bone remodeling in rats.

Biomaterials for periodontal regeneration: a review of ceramics and polymers

Periodontal disease is characterized by the destruction of periodontal tissues. Various methods of regenerative periodontal therapy, including the use of barrier membranes, bone replacement grafts, growth factors and the combination of these procedures have been investigated. The development of biomaterials for tissue engineering has considerably improved the available treatment options above. They fall into two broad classes: ceramics and polymers. The available ceramic-based materials include calcium phosphate (eg, tricalcium phosphate and hydroxyapatite), calcium sulfate and bioactive glass. The bioactive glass bonds to the bone with the formation of a layer of carbonated hydroxyapatite in situ. The natural polymers include modified polysaccharides (eg, chitosan,) and polypeptides (collagen and gelatin). Synthetic polymers [eg, poly(glycolic acid), poly(L-lactic acid)] provide a platform for exhibiting the biomechanical properties of scaffolds in tissue engineering. The materials usually work as osteogenic, osteoconductive and osteoinductive scaffolds. Polymers are more widely used as a barrier material in guided tissue regeneration (GTR). They are shown to exclude epithelial downgrowth and allow periodontal ligament and alveolar bone cells to repopulate the defect. An attempt to overcome the problems related to a collapse of the barrier membrane in GTR or epithelial downgrowth is the use of a combination of barrier membranes and grafting materials. This article reviews various biomaterials including scaffolds and membranes used for periodontal treatment and their impacts on the experimental or clinical management of periodontal defect.

Translational research and therapeutic applications of stem cell transplantation in periodontal regenerative medicine

Stem cells have received a great deal of interest from the research community as potential therapeutic "tools" for a variety of chronic debilitating diseases that lack clinically effective therapies. Stem cells are also of interest for the regeneration of tooth-supporting tissues that have been lost to periodontal disease. Indeed, substantial data have demonstrated that the exogenous administration of stem cells or their derivatives in preclinical animal models of periodontal defects can restore damaged tissues to their original form and function. As we discuss here, however, considerable hurdles must be overcome before these findings can be responsibly translated to novel clinical therapies. Generally, the application of stem cells for periodontal therapy in clinics will not be realized until the best cell(s) to use, the optimal dose, and an effective mode of administration are identified. In particular, we need to better understand the mechanisms of action of stem cells after transplantation in the periodontium and to learn how to preciously control stem cell fates in the pathological environment around a tooth. From a translational perspective, we outline the challenges that may vary across preclinical models for the evaluation of stem cell therapy in situations that require periodontal reconstruction and the safety issues that are related to clinical applications of human stem cells. Although clinical trials that use autologous periodontal ligament stem cells have been approved and have already been initiated, proper consideration of the technical, safety, and regulatory concerns may facilitate, rather than inhibit, the clinical translation of new therapies.

Effects of EMD in combination with bone swaging and calcium phosphate bone cement on periodontal regeneration in one-wall intrabony defects in dogs

BACKGROUND AND OBJECTIVE

Although the application of EMD is a widely accepted periodontal-regenerative therapy, its effects on noncontained intrabony defects are unpredictable because of the lack of a space-making property. The combined use of EMD and autogenous bone grafts reportedly stimulates significant periodontal regeneration in intrabony defects. The aim of the present study was to evaluate the effects of EMD in combination with bone swaging (BS) and injectable calcium phosphate bone cement (CPC), which was placed into the spaces between the grafted swaged bone and the proximal host bone, on periodontal healing in one-wall intrabony defects in dogs.

MATERIAL AND METHODS

One-wall intrabony defects (3 mm wide and 5 mm deep) were surgically created on the mesial and distal sides of the bilateral mandibular premolars in four dogs. The 16 defects were assigned to one of the following treatments: EMD only, BS only, EMD with BS (EMD + BS), or EMD with BS and CPC (EMD + BS + CPC). The animals were killed 8 wk after surgery for histologic evaluation.

RESULTS

The height of newly formed bone was significantly greater in the EMD + BS + CPC group (3.73 ± 0.30 mm) than in the BS-only (2.74 ± 0.33 mm; p < 0.05) and EMD + BS (2.88 ± 0.98 mm; p < 0.05) groups. The area of newly formed bone was significantly larger in the EMD + BS + CPC group (5.68 ± 1.66 mm(2)) than in the EMD-only (3.68 ± 0.33 mm(2); p < 0.05), BS-only (3.48 ± 1.26 mm(2); p < 0.05) and EMD + BS (3.38 ± 1.37 mm(2); p < 0.05) groups. The EMD-only (4.63 ± 0.42 mm), EMD + BS (4.67 ± 0.30 mm) and EMD + BS + CPC (4.78 ± 0.54 mm) groups showed significantly greater cementum formation than did the BS-only group (3.93 ± 0.56 mm; p < 0.05).

CONCLUSION

These results indicate that treatment with EMD + BS + CPC promotes favorable periodontal healing in one-wall intrabony defects in dogs.

Enhanced wound healing associated with Sharpey's fiber-like tissue formation around FGF-2-apatite composite layers on percutaneous titanium screws in rabbits

BACKGROUND

Pin-tract infections are the most common complications of external fixation. To solve the problem, we developed a fibroblast growth factor-2 (FGF-2)-apatite composite layer for coating titanium screws. The purpose of this study was to elucidate the mechanism of the improvement in infection resistance associated with FGF-2-apatite composite layers.

METHOD

We analyzed FGF-2 release from the FGF-2-apatite composite layer and the mitogenic activity of the FGF-2-apatite composite layer. We evaluated time-dependent development of macroscopic pin-tract infection around uncoated titanium control screws (n = 10). Screws coated with the apatite layer (n = 16) and FGF-2-apatite composite layer (n = 16) were percutaneously implanted for 4 weeks in the medial proximal tibia in rabbits.

RESULTS

A FGF-2-apatite composite layer coated on the screws led to the retention of the mitogenic activity of FGF-2. FGF-2 was released from the FGF-2-apatite composite layer in vitro for at least 4 days, which corresponds to a period when 30% of pin-tract infections develop macroscopically in the percutaneous implantation of uncoated titanium control screws. The macroscopic infection rate increased with time, reaching a plateau of 80-90% within 12 days. This value remained unchanged until 4 weeks after implantation. The screws coated with an FGF-2-apatite composite layer showed a significantly higher wound healing rate than those coated with an apatite layer (31.25 vs. 6.25%, p < 0.05). The interfacial soft tissue that bonded to the FGF-2-apatite composite layer is a Sharpey's fiber-like tissue, where collagen fibers are inclined at angles from 30 to 40° to the screw surface. The Sharpey's Wber-like tissue is rich in blood vessels and directly bonds to the FGF-2-apatite composite layer via a thin cell monolayer (0.8-1.7 μm thick).

CONCLUSION

It is suggested that the enhanced wound healing associated with the formation of Sharpey's fiber-like tissue triggered by FGF-2 released from the FGF-2-apatite composite layer leads to the reduction in the pin-tract inflammation rate.

The combination of purified recombinant human platelet-derived growth factor-BB and equine particulate bone graft for periodontal regeneration

BACKGROUND

The objective of this study is to evaluate the potential for periodontal regeneration of a critical-sized defect with the application of recombinant human platelet-derived growth factor (rhPDGF-BB) combined with either a particulate equine or a β-tricalcium phosphate (β-TCP) matrix.

METHODS

Critical-sized intrabony 2-wall defects were created bilaterally on the distal surface of the second premolar and the mesial surface of the first molar in nine hounds. Twelve defects received rhPDGF-BB/equine treatment, 12 defects received rhPDGF-BB/β-TCP treatment, and the remaining 12 sites served as sham-surgery controls. The animals were sacrificed after a 10-week healing period.

RESULTS

Clinical healing was uneventful without obvious signs of overt gingival inflammation. Histologic and histomorphometric analyses revealed statistically that there were differences among the three groups in terms of new bone formation (P <0.001). The amount of test material for both rhPDGF-BB/equine and rhPDGF-BB/β-TCP groups was comparable, but the amount of newly formed bone was significantly higher (P <0.01) in favor of the rhPDGF-BB/equine group. The amount of new cementum formed for the rhPDGF-BB/equine group (4.8 ± 1.3 mm) was significantly higher (P =0.001) than the sham-surgery control group (1.7 ± 1.9 mm).

CONCLUSION

Both rhPDGF-BB/equine and rhPDGF-BB/β-TCP have the potential to support the regeneration of the periodontal attachment apparatus.

Treatment of 3-wall intrabony defects in patients with chronic periodontitis with autologous platelet-rich fibrin: a randomized controlled clinical trial

BACKGROUND

Platelet-rich fibrin (PRF) is considered a second-generation platelet concentrate that is widely used in osseous regeneration. The present study aims to explore the clinical and radiographic effectiveness of autologous PRF in the treatment of intrabony defects in patients with chronic periodontitis.

METHODS

Fifty-six intrabony defects were treated with either autologous PRF with open-flap debridement or open-flap debridement alone. Clinical parameters such as the probing depth (PD) and periodontal attachment level (PAL) were recorded at baseline and 9 months postoperatively. The defect fill at baseline and 9 months was calculated on standardized radiographs by using image-analysis software.

RESULTS

The mean PD reduction was greater in the test group (4.55 ± 1.87 mm) than in the control group (3.21 ± 1.64 mm), whereas the mean PAL gain was also greater in the test group (3.31 ± 1.76) compared to the control group (2.77 ± 1.44 mm). Furthermore, a significantly greater percentage of mean bone fill was found in the test group (48.26% ± 5.72%) compared to the control group (1.80% ± 1.56%).

CONCLUSIONS

Within the limits of the present study, there was greater PD reduction, PAL gain, and bone fill at sites treated with PRF with conventional open-flap debridement compared to conventional open-flap debridement alone. However, a long-term, multicentered randomized controlled clinical trial is required to know the clinical and radiographic effects of PRF on bone regeneration.

Fibroblast growth factors: biology, function, and application for tissue regeneration

Fibroblast growth factors (FGFs) that signal through FGF receptors (FGFRs) regulate a broad spectrum of biological functions, including cellular proliferation, survival, migration, and differentiation. The FGF signal pathways are the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, among which the RAS/MAP kinase pathway is known to be predominant. Several studies have recently implicated the in vitro biological functions of FGFs for tissue regeneration. However, to obtain optimal outcomes in vivo, it is important to enhance the half-life of FGFs and their biological stability. Future applications of FGFs are expected when the biological functions of FGFs are potentiated through the appropriate use of delivery systems and scaffolds. This review will introduce the biology and cellular functions of FGFs and deal with the biomaterials based delivery systems and their current applications for the regeneration of tissues, including skin, blood vessel, muscle, adipose, tendon/ligament, cartilage, bone, tooth, and nerve tissues.