PURPOSE: Increased bone regeneration has been achieved through the use of stem cells in combination with graft material. However, the survival of transplanted stem cells remains a major concern. The purpose of this study was to evaluate the viability of transplanted mesenchymal stem cells (MSCs) at an early time point (24 hours) based on the type and form of the scaffold used, including type I collagen membrane and synthetic bone. METHODS: The stem cells were obtained from the periosteum of the otherwise healthy dental patients. Four symmetrical circular defects measuring 6 mm in diameter were made in New Zealand white rabbits using a trephine drill. The defects were grafted with 1) synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×105 MSCs, 2) collagen membrane and 1×105 MSCs, 3) β-TCP/HA+collagen membrane and 1×105 MSCs, or 4) β-TCP/HA, a chipped collagen membrane and 1×105 MSCs. Cellular viability and the cell migration rate were analyzed. RESULTS: Cells were easily separated from the collagen membrane, but not from synthetic bone. The number of stem cells attached to synthetic bone in groups 1, 3, and 4 seemed to be similar. Cellular viability in group 2 was significantly higher than in the other groups (P<0.05). The cell migration rate was highest in group 2, but this difference was not statistically significant (P>0.05). CONCLUSIONS: This study showed that stem cells can be applied when a membrane is used as a scaffold under no or minimal pressure. When space maintenance is needed, stem cells can be loaded onto synthetic bone with a chipped membrane to enhance the survival rate.
Bone Regeneration ; Bone Transplantation ; Cell Movement ; Cell Survival ; Collagen ; Collagen Type I ; Humans ; Membranes ; Mesenchymal Stromal Cells ; Periosteum ; Rabbits ; Space Maintenance, Orthodontic ; Stem Cells ; Survival Rate ; Tissue Scaffolds ; Transplants

BACKGROUND AND OBJECTIVES: Consonants are uttered in the high frequency range in speech to bring out understanding of our language. As consonants convey most of the word information, listeners with high-frequency hearing loss find it hard to understand speech. Non-linear frequency compression (NLFC) technology compresses and moves higher frequencies into a lower frequency region where better residual hearing is present. The purpose of this study was to evaluate clinical effectiveness of NLFC technology in patients with high-frequency hearing loss. SUBJECTS AND METHOD: Twelve ears representing patients with sloping, high-frequency sensorineural hearing loss were involved in this study. Pure-tone audiometry and Threshold Equalizing Noise Test were conducted initially in all subjects. The subjects were tested in the counter-balanced order, and had two months of everyday experience with NLFC on/off before testing took place. A resting period intervened the two phases. Performance was repeatedly evaluated with Sound Field Audiometry, Word Recognition Score, Reception Threshold for Sentences and Korean version of International Outcome Inventory for Hearing Aids. RESULTS: Cochlear dead region was detected on 4 kHz of both ears in only one subject. Each subject showed diverse performance and satisfaction with active NLFC condition. Typically, audibility of high-frequency pure-tones improved with NLFC-on condition. However, speech perception both in quiet and noise was not much improved when compared with NLFC-off condition. CONCLUSION: The NLFC technology could improve audibility in high-frequency, but failed to demonstrate benefits regarding speech perception. Further research is needed to validate the effectiveness of the NLFC technology especially in terms of speech intelligibility.
Audiometry ; Audiometry, Pure-Tone ; Ear ; Hearing ; Hearing Aids ; Hearing Loss, High-Frequency* ; Hearing Loss, Sensorineural ; Humans ; Noise ; Speech Intelligibility ; Speech Perception