Staged implant placement after defect regeneration using biphasic calcium phosphate materials with different surface topographies in a minipig model.

OBJECTIVE: To assess the influence of biphasic calcium phosphate materials with different surface topographies on bone formation and osseointegration of titanium implants in standardized alveolar ridge defects. MATERIALS AND METHODS: Standardized alveolar ridge defects (6 × 6 mm) were created in the mandible of 8 minipigs and filled with three biphasic calcium phosphate materials (BCP1-3, 90% tricalcium phosphate/10% hydroxyapatite) with different surface properties (micro- and macroporosities) as well as a bovine-derived natural bone mineral (NBM) as a control. At 12 weeks, implants were placed into the augmented defects. After further 8 weeks of healing, dissected blocks were processed for histological analysis (e.g., mineralized (MT), residual bone graft material (BS), bone-to-implant contact (BIC)). RESULTS: All four biomaterials showed well-integrated graft particles and new bone formation within the defect area. MT values were comparable in all groups. BS values were highest in the NBM group (21.25 ± 13.52%) and markedly reduced in the different BCP groups, reaching statistical significance at BCP1-treated sites (9.2 ± 3.28%). All test and control groups investigated revealed comparable and statistically not significant different BIC values, ranging from 73.38 ± 20.5% (BCP2) to 84.11 ± 7.84% (BCP1), respectively. CONCLUSION: All bone graft materials facilitated new bone formation and osseointegration after 12 + 8 weeks of healing.

Bone tissue response to an oily calcium hydroxide suspension in tibial defects. An experimental pilot study in minipigs.

OBJECTIVES: The present study was conducted to evaluate the bone tissue response after the application of an oily calcium hydroxide suspension (OCHS) into defects created in the tibial bone of minipigs. MATERIALS AND METHODS: Standardized defects (2 ccm) were created into the tibia of 4 Goettinger minipigs. Defects in the test group (n = 4) were filled with OCHS (Osteora, DFS-Diamon, Riedenburg, Germany). Defects in the control group (n = 4) were filled with venous blood. Animals were sacrificed after healing periods of 4 and 8 weeks. Tibias were dissected, soft tissues removed and processed for histological analysis. Digital images (×200) were evaluated using the software CellD (Soft Imaging System, Münster, Germany). The following histomorphometrical landmarks were identified: defect size, mineralized tissue, non-mineralized tissue and residual OCHS. RESULTS: Healing was uneventful in all four animals. In the test group, new bone formation was observed in the vicinity of the defect margins whereas the centre of the defect was dominated by non-mineralized tissue. Mean percentages of mineralized tissue after 4 weeks were 23.01% in the test group vs. 43.45% in the control group. The mean value for residual OCHS was 7,11% at 4 weeks. After 8 weeks mean percentages of mineralized tissue were 28.15% in the test group vs. 44.39% in the control group as well as 7.05% for residual OCHS. CONCLUSION: Within the limits of the present pilot study it can be concluded that OCHS did not have a beneficial effect on new bone formation. To prove an osteoinductive potential of OCHS further studies based on a higher number of samples are needed.

Effect of pulverized natural bone mineral on regeneration of three-wall intrabony defects. A preclinical study.

AIMS: The objective of this study is to evaluate the effects of a paste-like bone substitute material with easy handling properties and improved mechanical stability on periodontal regeneration of intrabony defects in dogs. MATERIALS AND METHODS: Mandibular and maxillary first and third premolars were extracted, and three-wall intrabony defects were created on second and fourth premolars. After a healing period of 3 months, acute type defects were filled with a paste-like formulation of deproteinized bovine bone mineral (DBBM) (particle size, 0.125-0.25 mm) in a collagenous carrier matrix (T1), pulverized DBBM (particle size, 0.125-0.25 mm) without the carrier (T2), or Bio-Oss® granules (particle size, 0.25-1.00 mm) as control (C). All defects were covered with a Bio-Gide® membrane. The dogs were sacrificed after 12 weeks, and the specimens were analyzed histologically and histometrically. RESULTS: Postoperative healing of all defects was uneventful, and no histological signs of inflammation were observed in the augmented and gingival regions. New cementum, new periodontal ligament, and new bone were observed in all three groups. The mean vertical bone gain was 3.26 mm (T1), 3.60 mm (T2), and 3.81 mm (C). That of new cementum was 2.25 mm (T1), 3.88 mm (T2), and 3.53 mm (C). The differences did not reach statistical significance. The DBBM particles were both incorporated in new bone and embedded in immature bone marrow. CONCLUSIONS: The results of this preclinical study showed that the 0.125-0.25-mm DBBM particles in a powder or paste formulation resulted in periodontal regeneration comparable to the commercially available DBBM. Osteoconductivity, in particular, was not affected by DBBM size or paste formulation. CLINICAL RELEVANCE: The improved handling properties of the paste-like bone substitute consisting of small DBBM particles embedded in a collagen-based carrier hold promise for clinical applications.