Within the limitations of this study, rhFGF-2 in gelatin/β-TCP sponges exhibits an increased potential to support periodontal wound healing/regeneration in canine recession-type defects.

Background:The alveolar ridge undergoes pronounced reduction in height and width following tooth extraction. This study aims to comparatively evaluate the potential for ridge preservation in extraction sockets with buccal bone deficiency of -tricalcium phosphate coated with poly lactide-co-glycolide ( -TCP/PLGA) and conventional particulate -TCP. Methods:In six beagles, maxillary first premolars were extracted after removal of their buccal bone plates. Standardized bone defects (4 [mesiodistal width] × 4 [buccopalatal width] × 5 [depth] mm) were created at the sites of extraction sockets and filled with -TCP/PLGA (test sites) or particulate -TCP (control sites). Microcomputed tomography, histologic, and histometric evaluations were performed 12 weeks post-surgery. Results:The test sites exhibited a significantly greater bone volume than the control sites (25.7 ± 2.14 versus 16.0 ± 3.3 mm 3 ), although no statistically significant difference was detected in bone material density (746.3 ± 23.9 versus 714.5 ± 37.0 g/cm 3 , respectively). Relative to the control sites, the test sites exhibited significantly greater alveolar-ridge coronal (2.0 ± 0.4 versus 1.1 ± 0.3 mm) and middle (2.9 ± 0.2 versus 2.1 ± 0.3 mm) horizontal widths and proportions of woven bone (50.3 ± 8.1% versus 38.0 ± 5.2%) and bone marrow (17.7 ± 6.6% versus 9.7 ± 4.1%) but a significantly lower proportion of connective tissue (10.7 ± 4.5% versus 18.3 ± 5.7%). Conclusion:Within the limitations of this study, the moldable -TCP/PLGA graft appears to exhibit a greater potential than the conventional particulate -TCP graft for ridge preservation of extraction sockets with buccal bone deficiency. K E Y W O R D Salveolar ridge augmentation, -tricalcium phosphate, biocompatible materials, dogs, osteogenesis, tooth extraction 1014

Background and Objective It is well known that recombinant human fibroblast growth factor‐2 (rhFGF‐2) signaling plays an important role in tissue repair and regeneration. rhFGF‐2 strongly binds to acidic gelatin via ionic linkages and is gradually released upon gelatin decomposition. On the other hand, the linkage between rhFGF‐2 and basic gelatin is so weak that most rhFGF‐2 is rapidly released from basic gelatin by simple desorption. Gelatin/β‐tricalcium phosphate (β‐TCP) sponges, which comprise 50 wt% gelatin and 50 wt% β‐TCP in a cross‐linked structure, can release rhFGF‐2 gradually owing to their electrical features. In a previous study, we reported that new bone height in the test group using rhFGF‐2 with acidic gelatin/β‐TCP sponges was significantly greater than that in the control group using acidic gelatin/β‐TCP sponges alone in a ridge augmentation model in dogs. However, whether these results depend on controlled release by the gelatin/β‐TCP sponges remains controversial. In this study, we evaluated the effects of controlled release by comparing acidic and basic gelatin/β‐TCP sponges with different isoelectric points (IEP) on ridge augmentation in dogs. Materials and Methods Twelve weeks after extraction of the maxillary second and third incisors of six dogs, critically sized saddle‐type defects (8 mm length × 4 mm depth) were surgically created bilaterally 2 mm from the mesial side of the canine. Acidic gelatin/β‐TCP sponges (IEP 5.0) soaked with 0.3% rhFGF‐2 were applied to the defect in the acidic group, whereas basic gelatin/β‐TCP sponges (IEP 9.0) soaked with 0.3% rhFGF‐2 were applied to the defect in the basic group. Twelve weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography (micro‐CT) and histological analyses. Results New bone area detected by micro‐CT analysis was significantly smaller in the basic group than in the acidic group. New bone height calculated by histologic sections was significantly lower in the basic group than in the acidic group. The total tissue height was lower in the basic group than in the acidic group. However, the differences between both sites were not significant. Conclusions These findings suggest that in ridge augmentation of saddle‐type defects, controlled release of rhFGF‐2 induces notably more alveolar bone formation than does short‐term application of rhFGF‐2.

No abstract

Objectives To evaluate the effect of enamel matrix derivative in liquid form (EMD‐liquid) as adjunct to grafting with natural bovine bone (NBB), on new bone formation and osseointegration in buccal dehiscence defects at dental implants. Material and methods In six beagles, 3 months after extraction of the mandibular premolars and first molars. Three titanium implants (3.3 Ø × 8.0 mm) were inserted, and dehiscence‐type defects (mesiodistal width 3 mm × 5 mm depth) were created on their buccal aspect. The defects were randomly assigned to one of the following three treatment groups: Group 1: NBB, Group 2: NBB/EMD‐L, Group 3: Control. All sites were covered with a collagen membrane. Histomorphometric measurements were performed after 3 months of healing. Results New bone area, bone‐to‐implant contact (BIC), and first BIC (fBIC) in the NBB and NBB/EMD‐L groups were significantly greater than in the control group (p < .05). Further, f‐BIC was at a significantly more coronal position in the NBB + EMD‐liquid group (0.4 ± 0.1 mm) compared with the NBB group (1.2 ± 0.2 mm). Conclusions Natural bovine bone grafting enhances bone regeneration and osseointegration at implants with buccal bone dehiscences compared with no grafting, and adjunct use of EMD‐liquid appears to further enhance bone formation and osseointegration.