Effects of Slow Programmable Cryopreservation on Preserving Viability of the Cultured Periodontal Ligament Cells from Human Impacted Third Molar

PURPOSE: This study was conducted to determine cell viability and differentiation capability of human periodontal ligament (PDL) cells and to elucidate the effects of cryopreservation on the activity of human third molar PDL cells by comparing PDL cells with and without cryopreservation. MATERIALS AND METHODS: Human PDL fibroblasts obtained from immature third molars were cultured and divided into two groups. The experimental group was cryopreserved with a slow freezing rate of 0.5degrees C/min from 4degrees C to -35degrees C followed by plunging in liquid nitrogen at -196degrees C and cultured after fast thawing. The control group was cultured without cryopreservation. Cell viability, growth capacity and morphology were evaluated in both groups. Bivariate statistics were used to compare 2 groups and linear mixed model analysis was used to investigate the growth trends difference over time. RESULT: Cell viability and growth capacity were not significantly different between the 2 groups (P>0.05). Cultured cell of both groups showed fibroblast-like in appearance, and there were no significant differences in morphology between 2 groups. The mixed model analysis revealed no significant difference of growth capacity between 2 groups over time (beta=-0.0009; P=0.138). CONCLUSION: This study demonstrates that cryopreservation under control does not affect the biological properties of PDL cells, supporting the feasibility of autotransplantation of cryopreserved impacted third molars.

A Radiographic Evaluation of Graft Height Changes after Maxillary Sinus Augmentation according to Single-unit Implants and Multi-unit Implants / 이화의대지

OBJECTIVES: This study was performed to evaluate whether there is the difference of graft height changes in radiographic evaluation in single implants and multiple implants after maxillary sinus floor augmentation with an auto-xenograft mixture. METHODS: The study group comprised 29 patients (16 men, 13 women; mean age, 56.5+/-12.4 years; range, 27 to 87 years) treated at the implant clinic of the Ewha Womans University Mokdong Hospital. They were treated with the sinus floor augmentation of lateral window technique and simultaneous placement of dental implants. Their implants have been evaluated for 42.4+/-10.5 months. To evaluate the height of grafted material, the real implant length was compared with that of panoramic radiography evaluated by a digital caliper (PACS program), and then the real height of grafted material was assumed. SPSS 19.0 was used in statistical analysis. Wilcoxon singed rank test was utilized for P value and Mann-Whitney for statistical significance in the changes of grafted height between single implants and multiple implants. The level of statistical significance was defined as P0.001). CONCLUSION: There was no statistical significance of radiographic graft height after maxillary sinus floor augmentation between single implants and multiple implants.

The retrospective study of marginal bone loss around dental implants according to different autogenous bone grafts

INTRODUCTION: This study examined the cumulative resorption of implants placed in a severely atrophic mandible and analyzed the radiologic bone resorption in the marginal bone, after an autogenous bone graft including both block and particulates that had been harvested from the ramus and iliac crest. MATERIALS AND METHODS: A retrospective study was performed on patients who had bone grafts for augmentation followed by implant installation in the mandible area from 2003 to 2008. Twelve patients (6 men and 6 women) who received 34 implants in the augmented sites were evaluated. Cumulative radiologic resorption around the implants was measured immediately, 3 months, 6 months and 12 months after implant installation surgery. RESULTS: The installed implant in grafted bone showed 0.84 mm marginal bone resorption after 3 months and 50% total cumulative resorption after 1 year. The mean marginal bone resorption around the implant installed in the grafted bone was 0.44 mm after 3 months, 0.52 mm after 1 year, after which it stabilized. The implant survival rate was 97% (failed implant was 1/34). Marginal bone resorption of the installed implant in the autogenous onlay block bone grafts was 0.98 mm after 3 months, which was significantly higher than that of a particulated bone graft (0.74 mm) (P<0.05). CONCLUSION: An autogenous graft including block type and particulate type is a predictable procedure for the use of dental implants in a severely atrophic mandible. Implant placement in augmented areas show a relatively high survival and minimal bone loss, as revealed by a radiologic evaluation.

The evaluation of surface roughness and polishing time between polishing systems / 대한치과보존학회지

OBJECTIVES: The purpose of this experiment was to evaluate four different polishing systems of their polishability and polishing time. MATERIALS AND METHODS: 4 mm diameter and 2 mm thickness Teflon mold was made. Z-250 (3M ESPE) hybrid composite resin was slightly overfilled and pressed with slide glass and cured with Optilux 501 for 40 sec each side. Then the surface roughness (glass pressed: control group) was measured with profilometer. One surface of the specimen was roughened by #320 grit sand paper and polished with one of the following polishing systems; Sof-Lex (3M ESPE), Jiffy (Ultradent), Enhance (Dentsply/Caulk), or Pogo (Dentsply/Caulk). The surface roughness and the total polishing time were measured. The results were analyzed with one-way ANOVA and Duncan's multiple range test. RESULTS: The surface roughness was lowest in Pogo, and highest in Sof-Lex. Polishing times were shortest with Pogo, and followed by the Sof-Lex, Enhance and Jiffy. CONCLUSIONS: One-step polishing system (Pogo) is very effective to get the smooth surface in a short time, therefore it can be recommended for final polishing system of the restoration.