Differential effects of bone graft substitutes on regeneration of bone marrow.

BACKGROUND: This study used a rat tibial marrow ablation model to test the hypothesis that bone remodeling within the medullary canal varies with bone graft materials of different chemical compositions and structural properties, impacting marrow cavity restoration. Bone graft materials were selected based on their relative resorption or degradation in vivo and their osteogenic properties. METHODS: Following ablation of the right tibial marrow in male Sabra-strain rats, materials were implanted in the proximal marrow cavity: poly-D,L-lactide-co-glycolide 75 : 25 (PLGA); coralline-hydroxyapatite (HA), calcium-sulfate (CaSO4), collagen-HA-tricalcium phosphate granules, anorganic bovine bone mineral, demineralized bone matrix (DBM), 45S5 Bioglass (BG), PLGA with BG 50 : 50, PLGA : BG 80 : 20, and PLGA and PLGA:BG 50 : 50 plus bone marrow (BM). Control tibias were ablated but received no implants. At 2 (endosteal bone healing), 4 (marrow cavity remodeling) and 8 weeks (marrow restoration), six to eight animals per group were euthanized and tibias processed for histomorphometry of proximal and distal medullary canals. RESULTS: Control tibias showed primary bone in proximal and distal medullary canals at 2 weeks, with trabeculae surrounded by cellular marrow. At 4 and 8 weeks, control trabeculae were thinned and marrow had more fat cells. In the treated tibias, trabecular bone volume (TBV) varied with time and was material specific. Most implants supported comparable TBV at 2 weeks. Sites with CaSO4 or DBM exhibited decreased TBV with time whereas trabecular bone was retained in proximal tibias containing other materials, closely juxtaposed to the implants. TBV did not always correlate directly with implant volume, but changes in BM volume were correlated inversely with TBV. Addition of BM increased marrow restoration in sites containing PLGA; however, BM reduced restoration of marrow when added to PLGA : BG. Although the presence of implants in the proximal tibia resulted in retention of trabecular bone, there was a time-dependent reduction in TBV in distal canals; the rate and extent of the distal TBV reduction were implant dependent. CONCLUSIONS: Thus, although many materials can support bone formation in the marrow cavity, bone quality, quantity, and physical relationship to the implant, and its rate of resorption differ in a material-dependent manner, resulting in differences in the restoration of marrow. CLINICAL RELEVANCE: Bone graft materials should be selected not only for their ability to support new bone formation but also for their impact on the remodeling phase of bone healing.

A 2-year follow-up of root coverage using sub-pedicle acellular dermal matrix allografts and subepithelial connective tissue autografts.

BACKGROUND: Coverage of roots exposed by gingival recession is one of the main objectives of periodontal reconstructive surgery. A large variety of mucogingival grafting procedures are available. However, the long-term effectiveness of this procedure is still not clear. This study compared the effectiveness of sub-pedicle acellular dermal matrix allografts with subepithelial connective tissue autografts in achieving root coverage 2 years postoperatively. METHODS: One hundred one (101) patients were treated with dermal matrix allografts (mean age, 28.4+/- 0.7 years; mean recession, 4.2 mm) and 65 patients treated with connective tissue graft (mean age, 30.1+/- 1.4 years; mean recession, 4.9 mm). All patients underwent full periodontal evaluation and presurgical preparation, including oral hygiene instruction and scaling and root planing. The exposed roots were thoroughly planed and covered by a graft without any further root treatment or conditioning. There were no differences in the average age, time of follow-up, or gender between the two groups. Patients were evaluated periodically between 1 and 2 years. Residual recession and defect coverage were assessed. RESULTS: Mean residual root recession after root coverage with acellular dermal matrix allograft was 0.2 +/- 0.04 mm, with defect coverage of 95.9% +/- 0.9%. Frequency of defect coverage was 82.2%. Root coverage was 98.8% +/- 0.2%, resulting in a frequency of root coverage of 100%. Gain in keratinized gingiva was 2.2+/- 0.04 mm and attachment gain was 4.5+/- 0.1 mm per patient. Connective tissue autografts resulted in mean residual root recession of 0.1+/- 0.04 mm, with percent defect coverage of 97.8%+/- 0.6% and frequency of defect coverage of 95.4%. Root coverage was 99.1%+/- 0.2%, and frequency of root coverage was 100%. Gain in keratinized gingiva was 3.0+/- 0.1 mm and attachment gain was 5.3+/- 0.2 mm per patient. No significant differences in final recession and root coverage between the two treatment methods were found. However, autografts resulted in significant increases in defect coverage, keratinized gingival gain, attachment gain, and residual probing depth. The clinical results were stable for the 2-year follow-up period. CONCLUSIONS: These results indicate that coverage of root by sub-pedicle acellular dermal matrix allografts or subepithelial connective tissue autografts is a very predictable procedure which is stable for 2 years postoperatively. However, subepithelial connective tissue autografts resulted in significant increases in defect coverage, keratinized gingival gain, attachment gain, and residual probing depth.

[The role of Matrix Metaloproteinases in the progression of periodontitis, and the use of specific inhibitors to these enzymes in the treatment of the periodontal disease].

Matrix Metaloproteinases (MMPs) play a crucial role in the pathogenesis of the periodontal disease. This group of enzymes can degrade most of the proteins that compose the extracellular matrix. Recently a new concept of treatment, the "host modulating therapy" (HMT) was developed. The rationale behind this concept is to inhibit the production of the inflammatory mediators and/or to block the production of the host MMPs and thus inhibiting disease production. In the recent years it was found that Tetracyclines (TC) decrease the levels of TNF-alpha, IL-1, Nitric Oxide, and prostaglandins, and via intra and extra cellular mechanisms inhibit the production and activation of the MMPs. A capsule of 20 mg Doxycycline, called later Low Dose Doxycycline (LDD), was the first HMT in the periodontal disease. In a 9 month study it was found that LDD bid after supragingival scaling statistically increased pocket reduction and attachment gain compared to supragingival scaling alone. However, this improvement was found only in pockets of 7 mm or more, and was not compared yet to periodontal supportive therapy every three month. There is a need for more basic and clinical research in the field of HMT in the treatment of periodontal disease, to expand our knowledge and clinical experience that will enable us to decide when and how to use medications to modulate host response.

Coverage of previously carious roots is as predictable a procedure as coverage of intact roots.

BACKGROUND: Coverage of roots exposed by gingival recession is one of the main objectives of periodontal reconstructive surgery. A variety of highly predictable and esthetically acceptable mucogingival grafting procedures are available for treating intact root surfaces. One of the indications for root coverage procedures is prevention of root caries. However, little is known about the ability to treat previously carious roots by mucogingival grafting, and even less is known about the outcome of such treatment. METHODS: Sixty patients with gingival recession were treated with subepithelial connective tissue grafts. During initial examination, 33 intact teeth with longstanding gingival recessions of 4.09 +/- 0.16 mm (mean +/- SEM) and 27 teeth with carious roots (restored and unrestored) and longstanding gingival recessions of 3.44 +/- 0.22 mm (mean +/- SEM) were found. Prior to grafting, any carious dentin and plastic restorations were removed. The exposed roots were thoroughly planed and covered by a subepithelial connective tissue graft without any further root treatment or conditioning. Patients were evaluated periodically between 1 and 6 years. Residual recession, defect coverage, and caries incidence were assessed. RESULTS: Recession was reduced to a similar extent on all teeth whether root caries was present (0.31 +/- 0.11 mm) or not (0.15 +/- 0.04 mm). This resulted in comparable defect coverages of 92.41 +/- 2.38% for previously carious roots and 97.46 +/- 0.79% for intact roots. In 44 cases, complete coverage of the recession was achieved. The results were stable, and no further recessions or recurrent caries were found during the periodic evaluations. CONCLUSIONS: These results indicate that coverage of previously carious roots with subepithelial connective tissue grafts is a very predictable procedure with results similar to those found on intact roots. This procedure may provide a definitive biological alternative for conventional restorative treatment modalities for root caries. Moreover, the results are more esthetic, biologically acceptable, and maintainable.

Root coverage and pocket reduction as combined surgical procedures.

BACKGROUND: One of the main objectives of periodontal reconstructive surgery is the coverage of exposed roots due to gingival recession. A large variety of mucogingival grafting procedures are available that give highly predictable and esthetically acceptable results when treating intact root surfaces. However, these procedures call for a second surgery site in the palate. The present study examines a series of cases in which connective tissue, obtained from the tuberosity during pocket reduction procedures in the posterior region of the maxilla, was used for root coverage. METHODS: Forty-four teeth from 25 patients with gingival recession of 3.30 +/- 0.14 mm (mean +/- SEM) were treated with subepithelial connective tissue grafts using connective tissue obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla. RESULTS: The mean root coverage recession after treatment was 0.16 +/- 0.06 mm, with effectiveness of coverage at 95.0% +/- 1.84 and a predictability of 84.1%. Periodontal probing depth reduction at the donor site was 4.08 +/- 0.24 mm. CONCLUSIONS: These results indicate that the subepithelial connective tissue graft obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla provides a very predictable and esthetic root coverage without the need for a second surgical site.

Association of smoking with periodontal treatment needs.

A total of 344 Jerusalem hospital personnel participated in the present survey which examined periodontal needs according to CPITN (a measure of treatment needs) and smoking habits. Females and younger subjects were found to be generally periodontally healthier than their male and older counterparts. The effect of both smoking and the number of cigarettes smoked were shown to have a clearly deleterious effect on periodontal status when assessed using the CPITN. Younger women were found to be most susceptible to this effect.

Familial gingival fibromatosis; no correlation with HLA-antigen. A family study.

Familial gingival fibromatosis is generally reported to be inherited as an autosomal dominant trait. We investigated 2 families with few siblings affected with gingival fibromatosis. No linkage between HLA antigen and the phenomenon was found. These results support the idea of the autosomal dominant nature of familial gingival fibromatosis.

The interleukin concept and the periodontal diseases.

The interleukins are hormone-like substances found at sites of inflammation such as in rheumatoid arthritis and periodontal disease. The present article analyzes a hypothetical mechanism of periodontal pathogenesis, whose etiology is still unclear despite its high prevalence.

Lichen planus evoked by periodontal surgery.

A case of Lichen Planus (LP) following periodontal surgery in a patient previously free of the disease is described. Genetic predisposition and lymphokine secretion stimulated by local trauma are suggested as a possible mechanism of the phenomenon. It is recommended that LP patients, especially those suffering from the erosive type, should be treated as conservatively as possible, minimizing the possibility of trauma to the oral tissues where local immunity may have been altered by a pathological process.

Changes in teeth and gingiva of dogs following laser surgery: a block surface light microscope study.

The effect of laser surgery on tissues of the periodontal apparatus was studied histologically in dogs using block surface light microscopy, a novel microscopical method. With this approach, changes in the hard and soft tissue components were concomitantly demonstrated; the method enabled preservation of the in situ relationship between these components. Following laser surgery, healing in the gingiva was delayed as suggested by the presence of epithelial ulcerations and dense inflammatory infiltrate. In the enamel and cementum the application of laser resulted in crater-like defects that could be avoided only partially by insertion of a tinfoil shield into the gingival sulcus. In the vicinity of the cementoenamel junction these defects were filled with epithelium or periodontal ligament fibers; the close proximity of the hard and soft tissues at the defect sites suggested occurrence of new attachment. Enamel defects located coronal to the gingiva contained bacterial plaque. These histologic results do not demonstrate any substantial advantage of laser over conventional knife gingivectomy. Such advantage may be accomplished with the design of a special intraoral handpiece and further experiments.

The effect of prolonged phenytoin administration on non-collagenous components of gingival tissue.

The hyperplastic gingivae of 11 epileptic patients on prolonged phenytoin therapy and those of control patients were excised during routine periodontal surgery. The tissues were homogenized and the hexosamine, uronic acid and total protein contents were determined. It was found that the gingivae of patients on prolonged phenytoin therapy had significantly raised hexosamine, uronic acid and total protein levels as compared with the controls. However, the relative concentration of the three parameters was similar in both groups. It is suggested that the enlargement of gingival tissue observed in patients who "respond" to prolonged phenytoin treatment may be the result not only of collagen over-production but also of the elevated levels of GAG.