Enamel matrix derivative and guided tissue regeneration in the treatment of dehiscence-type defects: a histomorphometric study in dogs.

BACKGROUND: The goal of this investigation was to histologically and histometrically evaluate the healing process of dehiscence-type defects treated by enamel matrix derivative (EMD) and/or guided tissue regeneration (GTR). METHODS: Seven mongrel dogs were used. Buccal osseous dehiscences were surgically created on the mesial roots of the mandibular third and fourth premolars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: open flap debridement (OFD), enamel matrix derivative (EMD), GTR with bioabsorbable membrane (GTR), and the combination of both procedures (EMD + GTR). After 4 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included gingival recession, epithelial length, connective tissue adaptation, new cementum, and new bone. RESULTS: A superior length of new cementum was observed in the sites treated by EMD (3.7 mm) and EMD + GTR (3.8 mm) in comparison with OFD (2.4 mm) (P < 0.05). No statistically significant differences were found in the remaining histometric parameters. CONCLUSIONS: Within the limits of this study, it can be concluded that EMD alone or in combination with GTR barriers may effectively promote new cementum formation. The combination of both therapies may not provide additional benefits.

Guided bone regeneration may be negatively influenced by nicotine administration: a histologic study in dogs.

BACKGROUND: A series of animal and in vitro data confirms that nicotine impairs bone healing, diminishes osteoblast function, and causes autogenous bone graft morbidity. Therefore, this study aimed to investigate the impact of nicotine on the healing of bone defects treated by the guided bone regeneration (GBR) principle. METHODS: Sixteen mongrel dogs were used. One defect was surgically created bilaterally and randomly assigned as an expanded polytetrafluoroethylene (ePTFE) membrane site or a non-membrane control site. The animals were randomly assigned to one of the following groups: group 1, placebo (n = 8) and group 2, subcutaneous administration of nicotine (2 mg/kg) twice daily (n = 8). After 4 months, the animals were sacrificed and the specimens routinely processed for semi-serial decalcified sections. The evaluated parameters were bone height, bone width, bone density, and bone area of newly formed bone. RESULTS: Intergroup analysis (Kruskal-Wallis) showed that membrane-protected defects in the placebo group demonstrated an increased bone area when compared to membrane-protected defects in the nicotine group and non-membrane sites, regardless of nicotine administration (P < 0.05). In addition, nicotine administration significantly affected bone density in membrane- and non-membrane-protected sites (P < 0.05). CONCLUSIONS: Within the limits of the present study, nicotine might affect, but not prevent, bone healing in defects treated by guided bone regeneration. The mechanisms of this effect should be investigated further.

Guided tissue regeneration in Class II furcation defects using a resorbable polylactic acid barrier.

PURPOSE: To evaluate, clinically, the use of guided tissue regeneration (GTR) with a resorbable polylactic acid membrane (Atrisorb) in the treatment of Class II furcation defects in humans. METHODS: The study included 10 patients with two comparable Class II furcations in lower molars. The lesions were randomly assigned to one of the treatments: GTR with an Atrisorb resorbable membrane (test) or open flap debridement (control). The following clinical parameters were recorded before the surgeries (baseline) and after a healing period of 6 months: relative vertical clinical attachment level, relative horizontal clinical attachment level, probing depths, position of the gingival margin and width of the keratinized tissue. RESULTS: After the intra-group comparison (baseline versus 6 months), statistically significant differences were found for the parameters: probing depth, relative vertical clinical attachment level and relative horizontal clinical attachment level, in both groups (P < 0.05). Comparing the two groups, a statistically significant difference was found in the probing depth reduction favoring the GTR group (P < 0.05). No significant differences were found in the other parameters.