The concentration of citric acid as dental root conditioner influences the behavior of fibroblasts from human periodontal ligament.

OBJECTIVE: This study investigated the behavior of fibroblasts from human periodontal ligament (hPLF) cultured on dental roots subjected to different protocols of citric acid conditioning. MATERIALS AND METHODS: 32 human teeth extracted due to advanced periodontal disease provided 63 radicular fragments, which were randomly divided in groups according to the treatment given to the surface: rinsing with saline solution for 90 s (C), 10 % citric acid (CA10), or 50 % citric acid (CA50). The treatments were applied during 90 s, 120 s and 180 s (n = 9). hPLF were cultured for 24, 48 and 72 h (n = 3) on the treated samples and analyzed by scanning electron microscopy (SEM) for surface area covered by cells and dentinal tubules widening. RESULTS: Excepting group C, all the other groups showed almost complete coverage of root surface by hPLF with time. At 24 h of cell culture, the largest area of coverage was seen in the samples treated with CA10-90 (98 ± 0.89 %) at 24 h of cell culture and this difference was significant (p < 0.05) in comparison to CA10-180 (84.04 ± 5.01 %), CA50-90 (63.28 ± 12.46 %), CA50-180 (56.59 ± 8.76 %) and C (0.06 ± 0.11 %). In all the other comparisons, there was no statistically significant differences between CA10 and CA50 (p > 0.05). Cells grown on surfaces treated with CA10 were more spread and flatten than in the CA50 specimens. CONCLUSIONS: Periodontally compromised roots surfaces conditioned with 10 % citric acid for 90 s resulted in better substrate for hPLF proliferation, in initial periods of culture than 50 % citric acid. The enlargement of the dentinal tubules did not seem to be influenced by the acid concentration.

Bone Graft and Substitutes Associated with Titanium Dome for Vertical Bone Formation in Osseointegrated Implants: Histomorphometric Analysis in Dogs.

PURPOSE: This animal study investigated vertical bone formation (VBF) around implants and used histomorphometric analysis to compare different bone-filling materials associated with a massive titanium dome as a tissue barrier. MATERIALS AND METHODS: Seven dogs were submitted to surgical procedures with extraoral access to the lower edge of the mandible, and four implants were semi-inserted in each animal. Each implant received one treatment: autogenous bone with clot (AB), control clot (C), synthetic graft (Biogran [BG]), or xenograft (Bio-Oss [BO]). Massive titanium domes were stabilized over the implants. Histologic analysis was performed after 3 months, and quantitative aspects were evaluated in extraosseous and intraosseous threads on Image Pro-Plus software. RESULTS: VBF around implants exhibited significant values in AB compared with other groups. BG and BO presented statistical equivalency to AB and C in the apposition and filling of extraosseous threads. There was no difference between groups for parameters evaluated in intraosseous threads. CONCLUSION: The experimental model was valid for evaluation of VBF around implants placed in atrophic mandibles. Considering the limitations of this study, histomorphometric analysis evidenced better outcomes for group AB. Even though groups BG and BO presented worse outcomes than AB, they were slightly better compared with the control group.