Introduction: Autologous bone is considered to be the “gold standard” for the reconstruction of the reabsorbed alveolar ridges. For small defects, autologous bone samples can be harvested from intraoral donor sites. However, extraoral donor sites are the first choice for any extensive augmentation of the alveolar ridges. The resorption of the bone grafts depends on several factors, including the recipient sites, the donor sites, volume of the bone grafts and whether or not the patient smokes. The aim of this study was to investigate the rate of autologous bone graft resorption, 4 months after the surgical reconstruction, according to their sites of origin, parietal or ramus, according to the grafted site, mandible or maxilla and according to the surgical indications. Patients and methods: 22 patients had 51 reconstructions of alveolar ridges with ramic or parietal onlay bone grafts. The increase of bone volume was assessed with computed tomography, immediately after augmentation (V0) and 4 months after the procedure (V1), before the placement of dental implants. Results: The mean rate of bone resorption was 26% for the parietal bone grafts and 27% for the ramus bone grafts after 4 months (p: ns). This rate was 26% for maxillary grafts and 25% for mandibular grafts (p: ns). This rate varies from 22% to 33% according to the etiology of the bone defect but these variations are not significant and ultimately, this rate of bone resorption was unaffected by the gender of patients. Conclusion: Based on these findings, the resorption of onlay grafts doesnʼt seems to be affected by the recipient and donor sites nor by the etiology of the bone defects. Parietal and ramic bone grafts showed limited resorption rates for the pre-implant reconstruction of alveolar ridges.

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Reliable operation of cellular programs depends crucially on the specificity of biomolecular interactions. In gene regulatory networks, the appropriate expression of genes is determined through the specific binding of transcription factors (TFs) to their cognate DNA sequences. However, the large genomic background likely contains many DNA sequences showing similarity to TF target motifs, potentially allowing for substantial non-cognate TF binding with low specificity. Whether and how non-cognate TF binding impacts cellular function and fitness remains unclear. We show that increased expression of different transcriptional regulators in Escherichia coli and Salmonella enterica can significantly inhibit population growth across multiple environments. This effect depends upon (i) TF binding to a large number of DNA sequences with low specificity, (ii) TF cooperativity, and (iii) the ratio of TF to DNA. DNA binding due to the limited specificity of promiscuous or non-native TFs can thus severely impact fitness, giving rise to a fundamental biophysical constraint on gene regulatory design and evolution.