Computed Tomographic Evaluation of Bone Quality of the Mandible Reconstructed by Particular Cellular Bone and Marrow Combined with Platelet Rich Plasma / Oral Science International

Concerning the bone structures of the mandible reconstructed by particular cellular bone and marrow (PCBM), platelet rich plasma (PRP) and tray, we have examined the possibility of implant insertion by clarifying the morphological conditions in each compact and cancellous bone on computed tomography (CT), and by observing the differences in their CT values.Using the computer software program Sim Plant (Materialize Dental, Leuven, Belgium), we morphologically observed 6 cases of implant inserted area after mandibular reconstruction and 11 cases of native bone, and examined the differences in their CT values. The osseointegration rate of each inserted implant was also evaluated.Compared with the native bone group, the PCBM reconstruction group had generally thin compact bone. In the over-3cm-length PCBM reconstruction group, the average CT value was 259.7 ± 94.4 HU (n = 3) in the cancellous bone, whereas in the native bone group, the average CT value was 528.9 ± 140.1 HU (n = 10). Therefore, the PCBM reconstruction group showed significantly lower CT value than the native bone group. However, in the under-3cm-length group, the PCBM reconstruction group showed no significant difference compared with the native bone group. The osseointegration rate of the inserted implants almost 6 months after insertion was 100% in the PCBM reconstruction group and 94.1% in the native bone group.Although the PCBM reconstructed bone had thinner cortical bone and showed lower CT value compared with the native bone, implant insertion was possible.

Preliminary Clinical Study to Evaluate the Relationship between Systemic Bone Turnover and the Microstructure of the Alveolar Bone / Oral Science International

The objective of this study was to assess the possibility of developing a clinical minimally invasive and standardized method to evaluate the relationship between the microstructure of the jaw bone and systemic bone turnover. For this purpose, we performed standardized bone biopsy of the alveolar bone, and compared the 3D bone microstructure using micro-computed tomography (micro-CT) with bone mineral density (BMD) of the lumbar spine and biochemical markers of bone turnover. We evaluated a total of 9 samples taken from 6 patients by standardized biopsy using a trephine bur. BMD was evaluated using dual energy X-ray absorptiometry (DXA). Regarding the biochemical markers of bone turnover, serum bone-specific alkaline phosphatase (BAP) and serum osteocalcin (OC) were used as bone formation markers, and urinary cross-linked N-telopeptides of type I collagen (NTx) and urinary deoxypyridinoline (DPD) were selected as bone resorption markers. We scanned micro-CT images of these samples. Bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Spac), fractal dimension, trabecular bone pattern factor (TBPf) and node-strut (Nd.Nd/TV, TSL/TV) were measured. Regarding the correlations between the parameters of bone microstructures, TB/TV, Tb.N, fractal dimension, and node-strut seemed to be positively correlated and Tb.Spac and TBPf seemed to be negatively correlated with each other, but Tb.Th seemed to have a low correlation with other parameters. OC and/or BAP showed a significantly high correlation with many structural parameters (p<0.05%). In conclusion, some microstructural parameters may change according to the systemic bone turnover.

Analysis of the Pattern of Maxillofacial Fracture by Five Departments in Tokyo / Oral Science International

We studied maxillofacial fractures treated by departments of oral and maxillofacial surgery in Tokyo. A retrospective review of records and radiographs for patients admitted during the 5-year period from 2000 to 2004 was conducted at five departments in Tokyo. Date, age, gender, cause of injury, fracture site, concomitant injury, domestic violence against women, and treatment were reviewed. 674 patients with maxillofacial fractures were admitted. Male-to-female ratio was 3.6:1. The most frequent age group was 21-25 years. Fractures of the mandible were most frequent (87%), followed by the maxilla (14%) and the zygomatic bone (12%). Thirty-one percent of fractures were due to traffic accidents, 29% to accidental falls, 23% to violence and 14% to sports. The incidence of maxillofacial fractures caused by traffic accidents was lower, and that caused by falls and violence were higher than in other countries. Seventeen percent of the maxillofacial fracture patients had concomitant injuries. The incidence of domestic violence-related maxillofacial fracture was 1.6% of all cases. These cases were mainly caused by a husband (55%) or a sexual partner (36%). Most patients (67%) were treated by open reduction surgery. However, condylar fracture alone was usually treated by closed reduction surgery.