Clinical applications of guided tissue regeneration: surgical considerations

Treatment of Stage III Grade C Periodontitis with Periodontal Regenerative Therapy including Guided Tissue Regeneration (GTR) and Recombinant Human Fibroblast Growth Factor (rhFGF)-2: A Case Report

This report describes a case of periodontitis treated with periodontal surgery including guided tissue regeneration (GTR) and recombinant human fibroblast growth factor (rhFGF)-2. The patient was a 54-year-old woman who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of swelling in the maxillary right gingiva. An initial examination revealed 30.4% of sites with a probing depth (PD) of ≥4 mm. The prevalence of sites with bleeding on probing was 57.7%. The plaque control record (PCR) score was 66.1%. Radiographic examination revealed vertical bone defects in the molar region. Based on these findings, the clinical diagnosis was generalized chronic periodontitis (Stage III, Grade C). Initial periodontal therapy yielded an improvement in periodontal conditions, with the PCR score reducing to 13.8%. Periodontal surgery was performed for teeth with a residual PD ≥4 mm. Guided tissue regeneration was performed on #37 and 47. A series of periodontal regenerative treatments comprising application of rhFGF-2 was performed on angular bone defects in #14, 15, 25, and 27. Open flap debridement was performed on #16, 17, 26, 36, and 46. Following evaluation, oral function was restored by placing all-ceramic crowns on #21 and 26. The patient was then placed on supportive periodontal therapy. In the present case of generalized chronic periodontitis, periodontal regenerative therapy with GTR and rhFGF-2 yielded stable periodontal conditions.

Periodontal regenerative therapy in endo-periodontal lesions: a retrospective study over 5 years

Purpose

The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions.

Methods

A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up.

Results

At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction (4.52±1.06 mm) than the DBBM + collagen membrane group (4.04±0.82 mm). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group (5.15±1.54 mm) was comparable to that of the DBBM + collagen membrane group (5.35±1.84 mm). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%.

Conclusions

This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

Amnion and Chorion Membranes: Potential Stem Cell Reservoir with Wide Applications in Periodontics

The periodontal therapy usually aims at elimination of disease causing bacteria and resolution of inflammation. It involves either resective or regenerative surgery to resolve the inflammation associated defects. Over the years, several methods have been used for achievement of periodontal regeneration. One of the oldest biomaterials used for scaffolds is the fetal membrane. The amniotic membranes of developing embryo, that is, amnion (innermost lining) and chorion (a layer next to it), have the properties with significant potential uses in dentistry. This paper reviews the properties, mechanism of action, and various applications of these placental membranes in general and specifically in Periodontics.

Periodontal regeneration using a bilayered PLGA/calcium phosphate construct

The regeneration of tissues affected by periodontal disease is a complex process; it encompasses the formation of bone, cementum and periodontal ligament. We developed a semi-rigid PLGA (polylactide-co-glycolide acid)/CaP (calcium phosphate) bilayered biomaterial construct to promote periodontal regeneration, which has a continuous outer barrier membrane and an inner topographically complex component. Our experimental model compared periodontal prophylaxis alone with prophylaxis and biomaterial implantation in the treatment of class II furcation defects in dogs. Clinical evaluation, micro-computed tomography, histology and backscattered electron imaging were used for data analysis. Healing occurred uneventfully and bone volumetric values, trabecular number and trabecular thickness were all significantly greater in the treated group; while trabecular separation was significantly greater in the control group. New cementum, bone, and periodontal ligament with Sharpey fibre insertions were only seen in the treated group. Although periodontal regeneration has been reported elsewhere, the advantages of employing our bilayered PLGA + CaP construct are twofold: 1)it did not collapse into the defect; and, 2) its inner side was able to retain the blood clot throughout the buccal defect. The result was greater periodontal regeneration than has previously been reported with traditional flexible membranes.

Clinical application of cone beam computed tomography for ideal absorbable membrane placement in interproximal bone defects

When a guided tissue regeneration (GTR) membrane is placed in an interproximal area, adjustment of the membrane is difficult because of the complex anatomy of the root surface and presence of bone defects, thus prolonging the surgery. This report describes the clinical application of cone beam computed tomography (CT) images to aid insertion of a barrier membrane in the treatment of interproximal bone defects. Using CT images, the membrane can be pre-cut into the optimal shape to cover the bone defect and fit the roots tightly, thus shortening the time required to adjust the GTR membrane, and providing excellent clinical outcomes.

Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning—an experimental study in dogs

Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group (p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an acellular type of cementum (1.32+/-0.83 mm in length and 3.16+/-0.23 microm in width) was also noted in six roots of test samples with an inconsistent distribution on the root surfaces. The amount of new cementum was significantly higher in the test group than the control group samples (p<0.01). The width of the cellular cementum in the control group was more than the cellular cementum in the test group, but the difference was not statistically significant (p>0.05). A firm attachment of acellular cementum to the root dentin with functional organization of its collagen fibers was noted, and, the accumulation and organization of cellular cementum in the control group was more irregular than the cellular cementum formed in the test group. The amount of new bone was 2.41+/-0.75 mm in the test and 1.09+/-0.46 mm in the control group at day 28. The rate of bone maturation (the number of osteons) was found higher in the test group (10.75+/-0.85) than the control group (5.50+/-0.86). Under the limitations of the study, our results reveal that when compared with root surface conditioning, enamel matrix proteins have more capacity for stimulating periodontal regeneration via their positive effects on root surfaces, i.e. inhibition of gingival epithelium down growth and stimulation of connective tissue proliferation and attachment to the root surfaces during wound healing. An acellular type of cementum regeneration and new alveolar bone formation by an accelerated osteoconductive mechanism are also achieved with application of enamel matrix proteins.

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.

Guided tissue regeneration update

The ultimate goal of periodontal therapy is to restore periodontal tissues lost through disease or trauma. The most predictable way to accomplish this goal is by guided tissue regeneration (GTR). The principle of GTR is to give preference to certain cells to repopulate the wound area to form a new attachment apparatus. Clinically this is accomplished by placing a barrier over the defect thereby excluding gingival tissues from the wound during early healing. The first generation of GTR barriers were non-resorbable which implies that they have to be removed in a second surgical procedure. Resorbable barriers have recently been introduced, changing GTR into a single-step procedure. Periodontal defects that will predictably benefit from GTR therapy are intrabony, furcation class II and gingival recession defects. This paper reviews the scientific evidence of what can be achieved by GTR procedures for various periodontal defects as well as factors of importance to increase the predictability of a successful treatment outcome.

Guided tissue regeneration with and without decalcified freeze-dried bone in mandibular Class II furcation invasions

The purpose of this study was to compare periodontal soft and hard tissue repair using expanded polytetrafluoroethylene (ePTFE) membranes with and without decalcified freeze-dried cortical bone allografts (DFDBA). Six patients with 17 mandibular Class II buccal molar furcal invasions received oral hygiene instructions followed by scaling and root planing. Baseline soft tissue measurements with periodontal probes were made to assess probing depths (PD), recession (REC), and probing attachment levels (PAL). After non-surgical therapy, 10 teeth were randomly selected as test sites (ePTFE + DFDBA) and 7 as controls (ePTFE alone). Full-thickness flaps were elevated, and open surgical measurements were made to determine alveolar crestal height (CEJ-AC) and vertical (CEJ-BDF) and horizontal (HPDF) defect depth. The ePTFE membranes were removed at 6 weeks. After 6 months, all sites were reentered and both soft tissue and open surgical measurements recorded. The following mean changes (mm) were found for ePTFE and ePTFE + DFDBA treated sites respectively: decreased PD = 1.5, 2.2; increased REC = 1.3, 1.3; loss(-)/gain PAL = -0.2, 0.8; decreased CEJ-BDF = 3.8, 5.0; increased CEJ-AC = 0.5, 0.4; and decreased HPDF = 2.3, 2.4. None of the changes were statistically significant. The addition of DFDBA to the GTR procedure did not significantly improve any of the mean soft tissue and open surgical measurements between control (ePTFE alone) and test (ePTFE+DFDBA) groups in mandibular Class II buccal furcations. Both treatment procedures resulted in significant decreases in PD, CEJ-BDF, and HPDF and a significant increase in REC. There were no differences for PAL and CEJ-AC within control and test groups seen with this sample. Larger randomized clinical trials are needed to more fully evaluate whether combined graft and GTR procedures offer an advantage over GTR alone.