Regeneración tisular guiada: fundamentos biológicos, técnicas quirúrgicas y resultados clínicos / Guided tissue regeneration: biological basis, surgical techniques and clinical results

El principio de R.T.G. está basado en evidencia científica que indica que el tipo de cicatrización a posteriori de la cirugía periodontal es determinada por los tejidos que primero repueblan la superficie de la raíz. La evaluación clínica de la R.T.G. ha mostrado resultados predecibles en defectos intraóseos de dos y tres paredes y furcaciones clase II. La R.T.G. es una modalidad terapéutica bien documentada y aceptada para facilitar la regeneración periodontal y debiera ser parte del armamentarium existente para el tratamiento de la periodontitis (AU)

Regeneración tisular guiada: fundamentos biológicos, técnicas quirúrgicas y resultados clínicos / Guided tissue regeneration: biological basis, surgical techniques and clinical results

El principio de R.T.G. está basado en evidencia científica que indica que el tipo de cicatrización a posteriori de la cirugía periodontal es determinada por los tejidos que primero repueblan la superficie de la raíz. La evaluación clínica de la R.T.G. ha mostrado resultados predecibles en defectos intraóseos de dos y tres paredes y furcaciones clase II. La R.T.G. es una modalidad terapéutica bien documentada y aceptada para facilitar la regeneración periodontal y debiera ser parte del armamentarium existente para el tratamiento de la periodontitis

Guided Tissue Regeneration and Bone Grafts in the Treatment of Furcation Defects.

The present study evaluated the effects of guided tissue regeneration (GTR), with and without demineralized freeze-dried cortical bone grafts, in the treatment of furcation defects in 4 female beagle dogs with naturally occurring periodontal disease. The root surfaces were thoroughly debrided. Four weeks later, full thickness facial and lingual mucoperiosteal flaps were reflected using inverse bevel incisions on both sides of the mandible involving the 2nd, 3rd, and 4th premolar, and the 1st molar teeth. Following debridement, notches were placed on the roots at the level of supporting bone. Test quadrants were randomly selected and furcations were filled with reconstituted, demineralized, freeze-dried human cortical bone grafts. Following bone grafting, all defects were covered with an expanded polytetrafluoroethylene (ePTFE) membrane, which was sutured with 4-0 sutures. Afterward, interproximal sutures were placed through the flaps, assuring the flaps covered the membranes completely. The contralateral side, serving as control, was treated by debridement only and application of ePTFE membrane. All membranes were removed 6 weeks after surgery. Dogs were sacrificed at 4 months after surgery. Both mesio-distal and bucco-lingual histologic sections were evaluated by descriptive histology. Linear measurements and surface area determination of the furcal tissues were carried out using the microscope attached to a digitizer. Twelve to 20 nonserial sections were made of the mid-buccal aspects of each root of each treated tooth. Half of these sections were stained with Harris' hematoxylin and eosin (H&E) and the other half stained with Mallory's trichrome stain. Additionally, another group of 12 to 20 non-serial sections cut in the mesio-distal direction were secured for the surface area measurements of the furcations. Mean values for each dog were obtained for test and control teeth. ANOVA procedure for a split plot design was employed. Periodontal healing following the use of guided tissue regeneration procedures resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive bone grafting did not appear to enhance regeneration. J Periodontol 1993; 64:1145-1153.

Effects of citric acid and fibronectin and laminin application in treating periodontitis / Efeito do ácido cítrico, fibronectina e aplicação de laminin no tratamento periodontal

To determine the effect on new connective tissue attachment of citric acid conditioning and fibronectin-laminin application in treating naturally occurring periodontitis, all 4 quadrants in each of 2 Beagle dogs were used. Each quadrant included: P2, P3, P4 and M1 teeth. 2 treatment modalities were employed and comparatively analyzed for differences in histological healing responses at 120 days after surgery. The treatments were: (1) surgery (mucoperiosteal flaps) plus citric acid; (2) surgery plus citric acid followed by fibronectin-laminin application. After scaling and root planing, coronal and root surface reference notches were placed for histometric measurements. Following each of the randomly assigned treatments, flaps were sutured. After sacrifice, tissue blocks of treated areas were decalcified and serially cut, obtaining bucco-lingual and mesio-distal sections. Using a Filar micrometer, 5 distances were measured on the buccal aspect: (1) from root surface notch to alveolar bone crest; (2) from root surface notch to coronal extent of the cementum; (3) from root surface notch to apical extent of the junctional epithelium; (4) from free gingival margin to apical extent of junctional epithelium; (5) from the coronal notch to the alveolar bone crest. Results showed no differences among the 5 measurements between the 2 treatments tested. On mesio-distal sections, surface area determinations were made in the furcations, evaluating the space occupied by new connective tissue, with or without bone, or by epithelium. For this, images were digitized using a Zeiss IBAS Image analysis system with a 4mB of array processor memory coupled to a Newvicon TV camera and a microcomputer. Significant differences were found, with increased values for both regenerative connective tissue and bone when surgery plus citric acid was followed by fibronectin-laminin application. Often, these tissues filled completely furcation areas above root surface reference notches

Revascularization following a combined gingival flap-split thickness flap procedure in monkeys / Revascularização após cirurgia a retalho em macacos

A combined technique (gingival flap-split thickness flap) was performed in monkeys. The clinical, histological and microvascular aspects of healing were studied, mainly focusing on the gingival flap, since some of the vessels supplying this area were severed during the second phase of the procedure. The animals were perfused with a combined solution of Pelikan carbon black and 10 por cento formalin solution and killed from 1 to 35 days postoperatively. Cleared specimens and regular histology were obtained. It was concluded that: (1) the remaining periosteal vessels and surrounding structures provided enough nutrition for the survival of the gingival flap, (2) the microvascularization was normal at the 14 days postoperative period in both the gingival flap and the apically positioned split areas and (3) the exposed connective tissue remained narrow and exhibited an irregular vascular arrangement throughout the experiment

Connective Tissue Response to Periodontal Dressings.

The effects of three periodontal dressings (Coe-Pak, PPC, Perio Putty) upon subcutaneous tissues in 26 Sprague-Dawley rats were investigated. The three dressings, and a control (Teflon), were placed into polyethylene tubes. Two tubes per animal were implanted on either side of the dorsal midline area. After 14 days the specimens were retrieved and prepared for histological examination. Three methods of scoring were utilized for evaluation. First, a system evaluating the overall number of inflammatory cells, connective tissue capsule thickness, and the vascular changes produced; second, an inflammatory cell count, the Inflammatory Index (I.I.), computing the inflammatory cells in a particular field of view for each material; and third, a Reaction Spread Index (R.S.I.) comparing the distance of the spread of the inflammatory reaction into the connective tissues. Statistical analysis of the data was carried out utilizing the Chi-square test and analysis of variance. While the three scoring systems utilized did result in some comparative variation in reactions, the overall order of decreasing severity was always PPC, Coe-Pak, Perio Putty, and Teflon.