Thirty (30) class I and class II recessions in 30 subjects were treated with a subepithelial connective tissue graft procedure. In one group (15 sites), the surgery was carried out in a traditional ...fashion: the epithelial collar of the graft was preserved and left exposed (CTG group). In the second group (15 sites), the epithelial collar of the graft was removed and the recession areas were conditioned with citric acid. The graft was then sutured and completely immersed under the facial flap which was coronally repositioned (CR group). Clinical assessments included probing depth, probing attachment level, surface area of the recession, and gingival width. These measurements were taken at baseline and at 6 months. In addition, an esthetic evaluation was done. The differences between treatments were not statistically significant except for the augmentation of gingiva (P < or = 0.05). Based on the midfacial measurements taken in the central area of the recession, the mean percentage of root coverage was 69.2%. In the CR group, 3 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 65.5%. In the CTG group, 5 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 94.4%. The mean surface area of root exposure was reduced from 13.82 mm2 and 13.67 mm2 to 2.15 mm2 and 2.34 mm2 for the CR group and the CTG group, respectively. One-hundred percent (100%) of good-to-moderate esthetic results were found by a panel of independent examiners; there was tendency toward better results in the CR group.
A wound stabilizing effect of expanded polytetrafluoroethylene (ePTFE) membranes was evaluated in supra-alveolar periodontal defects in 5 beagle dogs. The defects, 5 to 6 mm in height, were ...surgically created around the 2nd, 3rd, and 4th mandibular premolar teeth in contralateral jaw quadrants. The root surfaces were conditioned with heparin, which, in this model, has been demonstrated to compromise periodontal healing and result in formation of a long junctional epithelium. Wound closure included application of ePTFE membranes around each premolar tooth in one jaw quadrant in each dog and flap positioning coronal to the cemento-enamel junction in both jaw quadrants. Healing progressed uneventfully except for 3 teeth in 2 dogs, which experienced membrane exposure. The dogs were sacrificed after a 4-week healing period and tissue blocks were prepared for histometric analysis. Connective tissue repair in heparin+membrane-treated teeth averaged 98% of the defect height compared to 84% in control heparin-treated teeth (P < or = 0.05). Junctional epithelium formation was smaller in membrane-treated teeth than in control teeth (P < or = 0.05) and was usually terminated coronal to the membrane. Bone regeneration was enhanced in membrane-treated teeth compared to controls (P < or = 0.01) and was strongly correlated to the area under the membrane in teeth without membrane exposure (r2 = 0.993; P = 0.002). This correlation was reduced when teeth with membrane exposure were included in the analysis (P < or = 0.05). Cementum regeneration was minimal under both treatment conditions. Root resorption was increased in membrane-treated compared to control teeth (P < or = 0.01).
Wound healing in an incisional wound is a highly predictable process which has been studied extensively hour-by-hour and day-by-day. Healing in a periodontal defect following gingival flap surgery ...is, conceptually, a more complex process as one wound margin consists of calcified tissue, including the avascular and rigid root surface. Another complicating factor in this wound healing is the transgingival position of the tooth. Experimental studies, however, have indicated that healing at a dento-gingival interface under optimal conditions occurs at the same rate as in a skin wound. Generally, periodontal healing is characterized by maturation of gingival connective tissue, limited regeneration of alveolar bone and cementum, and the formation of a long junctional epithelium. Such observations have nurtured the hypothesis that the epithelium of the surgical flap needs to be prevented from early access to the root surface during the healing period to achieve connective tissue repair of the root surface-gingival flap interface. Recent experimental findings suggest, however, that connective tissue repair to the root surface following reconstructive periodontal surgery is a function of the establishment and maintenance of a root surface-adhering fibrin clot. Since fibrin adherence to the wound margins is a natural event, it is additionally suggested that apical migration of the gingival epithelium in periodontal surgical wounds may only follow interruption of the adherence of the fibrin clot to the root surface.
This study evaluated a biodegradable polylactic acid matrix as a wound stabilizing implant in reconstructive periodontal surgery. Supra-alveolar circumferential periodontal defects, 5 to 6 mm large, ...were surgically created around the mandibular premolars in 7 beagle dogs. The root surfaces in left and right jaw quadrants were treated with either heparin or saline. In this model, root surface treatment with heparin compromises periodontal repair and results in a long junctional epithelium and a reduced connective tissue repair to the root surface, whereas saline treatment results in almost complete connective tissue repair. Following heparin or saline treatment a polylactic acid implant was placed on 1 premolar in each quadrant. After 4 weeks of wound healing, the dogs were sacrificed and tissue blocks prepared for histometric analysis. Postoperatively, the implant became exposed and infected in 3 dogs and had to be removed. Therefore, the results reflect the 4 dogs in which healing progressed uneventfully. Connective tissue repair to the root surface in teeth treated with heparin averaged 82% of the defect height. Mean connective tissue repair in teeth treated with heparin and the implant was significantly greater and comprised approximately 99% of the defect height (P less than 0.05). Teeth treated with saline either with or without the implant also healed with almost complete connective tissue repair. The results support the importance of wound stabilization in periodontal wound healing. Development of biodegradable implant systems aimed at stabilizing and supporting the healing wound seems a desirable direction for future research in regenerative periodontal procedures.
The purpose of the present study was to determine the diagnostic value of clinical scores of supragingival plaque, bleeding, suppuration and probing depth to predict probing attachment loss in ...patients on maintenance following nonsurgical periodontal therapy. Non‐molar teeth in 39 subjects were monitored and the above scores were repeatedly obtained throughout 5 years of observation following initial treatment. Probing attachment loss between 0–60 months was determined by a combination of linear regression analysis and end‐point analysis. The results revealed that all the investigated scores were associated with probing attachment loss. This association was demonstrated by improved diagnostic predictability along with increased frequency or magnitude of the various scores. Also, the diagnostic predictability improved with increase in length of time for recording of the scores. The diagnostic predictability of either accumulated plaque scores and accumulated bleeding scores reached a maximum of about 30%. Residual probing depth ≥7 mm reached a predictability of around 50% and increase in probing depth ≥ 1.0 mm reached about 80% after 60 months. Thus, of the clinical scores investigated, increase in probing depth was found to be most valuable in predicting probing attachment loss.
Sixteen intrabony defects in 12 patients were treated by gingival flap surgery including root surface debridement and placement of an expanded polytetrafluoroethylene (ePTFE) membrane. The membranes ...were removed after 4 to 6 weeks and examined by scanning electron microscopy (SEM) for bacterial contamination and adherent connective tissue elements. Twelve months postsurgery, the defect sites were reexamined for changes in probing attachment level and probing bone level. Comparison of ultrastructural findings and clinical observations revealed that extent of bacterial contamination of the membrane correlated inversely with clinical assessment of attachment gain. The results indicate that the extent of oral exposure and bacterial contamination of the ePTFE membrane at the time of removal may be an indicator of the long-term success or failure of the regenerative procedure.
The objective of these studies was to follow early healing at the dentin-connective tissue interface. Small dentin blocks were surgically implanted in bone cavities under mucoperiosteal flaps in the ...edentulous alveolar ridges of five beagle dogs at various times. In two separate experiments, wound maturation on native dentin surfaces and on citric acid or heparin conditioned dentin surfaces was observed. Block specimens including bone, dentin, and surrounding soft tissues were obtained at 10 minutes, 1 and 6 hours, and 1, 3, and 7 days after flap closure and prepared for light and transmission electron microscopic examination of the interface. The very initial attachment to native dentin was mediated by a granular precipitate. At 1 and 6 hours, the intercellular matrix was more organized with fibrin formation around red blood cell aggregates and at the dentin surface. Polymorphonuclear leukocytes were observed throughout the interface. Red blood cells were undergoing degradation at day 1 and polymorphonuclear cells were prevalent at the dentin surface. The 3-day observation interval was characterized by further maturation of the fibrin clot. Macrophages were observed near the dentin surface and fibroblasts could be identified. The 7-day specimens exhibited areas of cell rich connective tissue attachment without inflammatory cells as well as areas showing the fibrin clot in various stages of decomposition. These observations suggest that connective tissue attachment to dentin surfaces is mediated by adsorption of plasma proteins to the surface and subsequent development and maturation of a fibrin clot. The sequence of healing events at dentin surfaces conditioned with citric acid or heparin was largely similar to healing at native dentin surfaces. However, at day 1 and later time points, clot adhesion to heparin-conditioned dentin appeared compromised, whereas the fibrin clot seemed to adhere to citric acid-conditioned dentin at all observation periods. These observations indicate that in the absence of mechanical trauma, epithelial proliferation, and infection, wound maturation at the dentin-connective tissue interface may not necessarily be affected by treatments that either enhance or inhibit clot adhesion to the dentin surface.
This report describes the healing patterns of large circumferential periodontal defects in the beagle dog. Approximately 5 mm large periodontal defects were created around the mandibular premolars ...(P2, P3 and P4) in 13 animals. The root surfaces were then instrumented to remove all cementum and the wounds immediately closed by replacing and suturing the flaps just coronal to the cemento‐enamel junction. Block biopsies were harvested after 4 weeks. Most of the surgically denuded root surface healed with connective tissue repair. Cementum formation and regeneration of alveolar bone was limited and averaged approximately 30% and 20%, respectively, of the defect height. Almost all teeth exhibited root resorption. Ankylosis was observed in 1/3 of the teeth. There was no difference in the healing response between the 3 premolars or their buccal and lingual surfaces. The range of healing responses indicates that a biological potential exists which makes this model useful for testing the effect of various root and wound conditioners in (1) enhancing cementum formation on the root surface, (2) increasing regeneration of alveolar bone and (3) preventing aberrant healing events such as root resorption and ankylosis. Conversely, whether such agents may compromise wound healing and result in reduced connective tissue repair may concomitantly be tested.
Twenty-four mandibular buccal Class II furcation lesions in 12 subjects were treated with reconstructive periodontal therapy including citric acid root treatment and replaced flap surgery. Twelve ...(12) of the lesions received expanded polytetrafluoroethylene (ePTFE) membranes to cover the furcation entrance (ePTFE group) whereas the remaining 12 lesions received a connective tissue graft over the furcation (CTG group). Clinical assessments, including probing depth, probing attachment level, location of gingival margin, direct bone probing, and defect volume, were taken at baseline and at 12 months reentry. In the ePTFE group 30% of the defect volume filled with bone; 36% of the defects exhibited complete bone closure. In the CTG group 19% of the defect volume filled with bone and 18% of these defects exhibited complete bone closure. There were no meaningful clinical differences between treatment groups except in horizontal probing depth change (P < or = 0.05). This study suggests that connective tissue grafts and ePTFE membranes have comparable potential in supporting bone regeneration in mandibular Class II furcation lesions. Further clinical trials with larger numbers of patients and a longer evaluation period are needed to fully compare these procedures.
A need exists for well-defined animal models to objectively evaluate surgical principles and a possible role for biochemical wound conditioning and biomaterials in promoting periodontal regeneration. ...To test an existing model for its usefulness in quantitative evaluation of periodontal wound healing, large supraalveolar periodontal defects were surgically created around the mandibular premolars (P2, P3, P4) in left or right jaw quadrants in 5 beagle dogs. The defects were exposed to the oral environment for 6 months and were then subjected to reconstructive flap surgery (chronic defects). Healing in these defects was compared to healing following reconstructive surgery in similar contralateral defects which had not been exposed to plaque and calculus (acute defects). The animals were sacrificed after a 4-week healing period and tissue blocks including teeth and surrounding structures were processed for histometric analysis. Mean defect height (+/- s.d.) for chronic and acute defects amounted to 4.6 +/- 0.3 and 4.4 +/- 0.4 mm, respectively. Mean connective tissue repair to the root surface in chronic defects amounted to 62% (range 49% to 74%) of the defect height. Mean connective tissue repair in the acute defects exceeded 94% of the defect height in 4 of the dogs, but amounted to only 48% in 1 dog. Regeneration of alveolar bone and cementum was limited under both experimental conditions. Root resorption was frequently encountered, whereas ankylosis was seen in only few teeth. This study indicates that healing may vary not only as a result of controlled experimental variables, but also due to differences in biological response between dogs or to fortuitous traumatic factors.
