Distance between implants has a potential impact of crestal bone resorption

Around dental implants exists a "biologic width" of few millimeters that have to be preserved in order to not have adverse effect on soft and hard tissues around implant. Because the minimum distance between adjacent implants has not been determined yet, we therefore, decided to perform a retrospective study on a series of spiral family implants [SFIs] to verify the minimum inter-implants' distance that has an impact on crestal bone resorption. Fifty-nine implants were investigated with a mean follow-up of 14 months. Implant diameter was 3.75, 4.2, 5 and 6 mm in 11 [18.6%], 29 [49.2%], 17 [28.8%] and 2 [3.4%] SFIs. Implant length was shorter than 13 mm, equal to 13 mm and 16 mm in 23 [39%], 23 [39%] and 13 [22%] SFIs. Implants were inserted to replace 13 incisors [22%], 7 cuspids [11.9%], 30 premolars [50.8%] and 9 molars [15.3%]. Twenty-seven fixtures were inserted in post-extractive sockets and the remaining 32 in healed bone; 36 [61%] were immediately loaded. In addition to the above mentioned implant-related factors, several host- and surgery-factors were investigated. Independent samples T-test, univariate and multivariate analysis were used to detect those variables associated with the clinical outcome. Data were evaluated with a two steps statistical analysis [i.e. univariate and multivariate] after having grouped implants in two series: those with an implant-implant distance less of 1.8 mm and those with an implant-implants distance greater than 1.8 mm. In univariate analysis, post-extractive implants and number of prosthetic units were statistically significant. In multivariate analysis, only post-extractive implants have a significant adverse effect on crestal bone resorption. Adjacent implants inserted with a distance lower and higher than 1.8 mm have difference in crestal bone resorption but this difference is not statistically significant in a short period follow up. This could due to the specific implant used that has a reverse conical neck. No statistical difference was detected between implant subtypes. Post-extractive implant insertion is the major determinant in terms of peri-implant bone resorption in a short period follow-up

A comparison between genetic portraits of normal osteoblasts and osteosarcoma cell lines.

BACKGROUND: Osteosarcoma (OS) is the most frequent malignant bone tumor occurring in young patients in the first two decades of life. Metastases are the cause of 90% of cancer deaths for patients with OS. OS of the jaw is rare and aggressive malignancy constitutes approximately 5-13% of all cases of skeletal OS. Chemotherapy plus surgery are the first choice for treatment. AIMS: Because OS cell lines (OCLs) should share a common pathway with primary OS and new drugs are screened in in vitro systems, new insight about the genetic profiling of OCLs is of paramount importance to a better understanding of the molecular mechanism of this rare tumor and detecting a potential target for specific therapy. MATERIALS AND METHODS: The SAOS2 and TE85 cell lines were analysed using DNA microarrays containing 19,000 genes. Several genes in which expression was significantly differentially expressed in OCLs vs. normal osteoblast (NO) were detected. RESULTS: The differentially expressed genes cover a broad range of functional activities: (a) cell cycle regulation, (b) cell differentiation, (c) apoptosis, and (d) immunity. CONCLUSION: The reported data can be relevant to a better understanding of the biology of OS and as a model for comparing the effect of drugs used in OS treatment.

Comparison between differential expressed miRNA of osteoblast-like cells cultured with P-15 vs. bio-oss

Bio-Oss is composed of anorganic bovine bone whereas P-15 is an analog of the cell binding domain of collagen. Both are widely used in several bone regeneration procedures in oral surgery. How these biomaterials act on osteoblast activity to promote bone formation is poorly understood. We attempted to get more insight using microRNA microarray techniques to investigate the translation regulation in osteoblasts exposed to P- 15 and Bio-Oss. By using miRNA microarrays containing 329 probe designed -from Human miRNA sequence, we identified in osteoblast-like cells line [MG-63] cultured with Bio-Oss[R] [Geistlich, Wolhusen, Switzerland] and P-15 [Ceramed, Lakewood, CO] several miRNA which expression is significantly modified. There were 4 up-regulated miRNA [i.e. let-7c, mir-27a, mir-125a, mir-30c] and 5 down-regulated miRNA [i.e. mir-23a, mir-320, let-7b, mir-145, mir-128a]. P-15 acts preferentially on homeobox genes whereas Bio-Oss activates preferentially extravellular matrix componets, cytokines and hormones. P-15 and Bio-Oss enhance the translation process of different BMPs: BMP1 and BMP4 the first material and BMP 3 and 11 the second one