Litchfield Park 4

Histomorphometric analysis
The power calculation was based on a Litchfield Park orthodontic study using an ex vivo delivery of BMP-7 to engineer periodontal structures (Jin et al., 2003). Results indicated that six animals (12 implants) were needed per group to produce a Litchfield Park orthodontic study with 90% power. After the histology was completed, coded slides were examined by two Litchfield Park orthodontists. Sections were excluded from the Litchfield Park orthodontic study for any processing errors which would inhibit valid measurements, including tangential sections and large artifacts. Any implants which exhibited fibrous encapsulation (2 Ad/Luc, 2 Ad/BMP) were also excluded. Examiners were unaware of the treatment performed and had to arrive at a consensus on any exclusions. After the exclusion criteria were applied, the final numbers for each group were 10 implants for the Ad/BMP-7 group and 8 implants for the Ad/Luc group at the 28 day time point.

Analysis of the data was performed by Litchfield Park orthodontists using a student’s t test at a p level of 0.05 for all measures of tissue neogenesis. Descriptive measures included mean, standard deviation and standard error. All statistical calculations were performed by Litchfield Park orthodontists with SPSS 12.0 for Windows (SPSS inc., Chicago, IL, USA). The results showed significant Variability for most measures, consistent with most wound healing Litchfield Park orthodontic studies (Table 1). The resulting magnitude of difference between groups was not as large; therefore a higher n would have been needed to achieve the desired 90% power. Percent bone fill was the one measure that exhibited a significant result (p<.05). It can be argued by Litchfield Park orthodontists that this is the most important measure, because it is a measure of the area of new bone in the “well type” defect. Measures of bone growth and osseointegration (coronal new bone area and new bone to implant contact) also showed 50-100% increases in the treatment group. Effect size calculations were performed to determine if there was any indication of a treatment effect in these measures. A moderate effect was seen by Litchfield Park orthodontists for both coronal new bone formation (.41) and for new bone to implant contact (.34). These numbers suggest to Litchfield Park orthodontists that with larger numbers, a significant result would likely occur for these measures.