Superficial topography and porosity of an absorbable barrier membrane impacts soft tissue response in guided bone regeneration.

BACKGROUND: Surface topography and porosity of barrier membranes is suggested to impact the soft and hard tissue response. In this study, the specific soft and hard tissue response characteristics of a synthetic polylactide membrane are evaluated including soft tissue inflammation, osteogenesis, and osteopromotion. METHODS: Analysis of porosity and surface topography of the test material was performed by scanning electron microscopy. Transosseous parietal defects were surgically created bilaterally in 32 BalbC/ByJ mice and treated either with the barrier (test) or sham-operated (control). Healing was assessed histologically and histomorphometrically with quantification of bone bridging. RESULTS: Scanning electron microscopy analyses of the barrier revealed a microstructure resembling cancellous bone. Interconnecting pores and channels, measuring between 6 and 60 microm in diameter, formed by smooth internal walls were observed throughout the device. Two distinct patterns of porosity were observed. The external surface of the membrane was characterized by a highly porous structure, with minimal interporous nodes and average pore sizes ranging between 6 and 20 microm in diameter. The internal surface was characterized by a minimal porous structure, with significant interporous nodes and average pore sizes ranging between 18 and 60 mum in diameter. Histomorphometric analyses demonstrated increased bone bridging by 60% and 300% in membrane-treated sites after 14 and 28 days of healing, respectively. The rough surface of the barrier contained significantly more giant cells, whereas the smooth surface contained significantly more inflammatory cells. CONCLUSION: The surface topographies engineered on different sides of the barrier promote differential soft tissue responses leading, however, to similar amounts of enhanced bone formation.

Efficacy of combined regenerative treatments in human mandibular class II furcation defects.

BACKGROUND: The treatment of molar furcation defects remains a considerable challenge in clinical practice. The degree of success in the management of furcation involvement is highly variable and inversely related to initial probing depth (PD) measurements in these lesions. The identification of clinical measurements influential to the treatment outcomes is critical to optimize the results of surgical periodontal therapy. Therefore, the objective of this study was to evaluate the clinical response of mandibular buccal Class II furcation lesions to a combined regenerative treatment modality. METHODS: Sixty patients were divided into two (n = 30) treatment groups. An experimental combined regenerative therapy (ET) was compared to open flap debridement (OFD). The ET was a combination of a composite graft consisting of bioabsorbable hydroxyapatite and tetracycline (3:1), a guided tissue regeneration barrier, and a coronally advanced flap. The clinical variables evaluated were plaque, bleeding on probing, gingival recession, PD, vertical attachment level (VAL), horizontal attachment level (HAL), furcation vertical height, furcation horizontal depth, and the amount of tissue under the barrier membrane at uncovering. Reevaluation was performed 12 months after the surgical procedure. RESULTS: Both treatments resulted in improvements in all clinical variables evaluated. Postoperative measurements revealed a reduction in PD of 3.65 +/- 0.6 mm and 0.60 +/- 1.0 mm; VAL gains of 3.05 +/- 0.6 mm and 0.65 +/- 0.6 mm and HAL gains of 3.45 +/- 1.3 mm and 0.55 +/- 0.7 mm in the ET and OFD groups, respectively. In the ET group, significant positive correlations were found between baseline PD and PD reduction at 12 months, and the initial VAL correlated positively with PD reduction and HAL gain. The horizontal furcation depth and amount of tissue formed under the membrane at uncovering correlated positively with PD reduction and HAL and VAL gains. For the OFD group, the initial PD correlated positively with PD reduction and VAL and HAL gains and correlated negatively with recession. Initial VAL correlated positively with PD reductions and VAL and HAL gains. The initial HAL correlated negatively with recession at 12 months. CONCLUSIONS: ET exhibited significantly better clinical results, with more PD reduction, HAL and VAL gains, and a higher frequency of furcation closure compared to OFD and showed promise as a regenerative treatment technique. The ability to predict a response to treatment based upon pretreatment parameters was not consistent between groups; thus, prediction of treatment outcomes based on pretreatment measurements should be carefully evaluated for each treatment modality.