[Evaluation of clinical application of ACP classification for edentulous patients].

OBJECTIVE: To evaluate clinical application of American College of Prosthodontics classification system for complete edentulism; and to analyze the relationship between clinician's rating of general degree of difficulty of each case and patients' rating of denture satisfaction. METHODS: One hundred and seven edentulous patients were examined clinically using American College of Prosthodontics (ACP) classification for complete edentulism. The least heights of patients' mandible were measured on panoramic radiographs. Clinician rated general degree of difficulty of each case on visual analogue scale. Six month following denture delivery, patients rated their denture using Mcgill satisfaction Visual Analog Scale (VAS). Multivariate linear regression analysis were conducted to analyze the relationship between clinician's rating of general degree of difficulty and mandibular bone height adjusting for confounding factors such as mandibular ridge form, soft tissue quality etc. Pearson correlation analysis was conducted to analyze the correlation between clinician's rating of case difficulty and patients' rating of denture satisfaction. RESULTS: Advanced residual ridge resorption were found in around 80% (83/105) of all the cases. When the least mandibular bone height were measured on panoramic radiographs, intra-examiner reliability was 0.96, inter-examiner reliability was 0.90. Cases were rated as more difficult when patients showed lower mandibular bone height, unfavorate ridge form (knife ridge and irregular ridge), mobile soft tissue and longer period of wearing time of their previous dentures. No significant correlation (r<0.1) was found between clinician's rating of degree of difficulty of each case and patients' rating of denture satisfaction 6 month following delivery of prostheses. Clinician rated cases in which patient's mandibular bone height was lower than 11 mm as 8.8%-16.1% more difficult than those in which patient's mandibular bone height was higher than 11 mm (P<0.05). CONCLUSION: ACP classification for complete edentulism showed good intra- and inter-examiner reliability, and is an useful tool for clinical evaluation of edentulous patients' oral condition. However, there was no significant correlation between clinicians' rating of difficulty of cases and patients' rating of denture satisfaction.

In vitro comparison of two titanium dental implant surface treatments: 3M™ESPE™ MDIs versus Ankylos®.

BACKGROUND: An ideal implant should have a surface that is conducive to osseointegration. In vitro cell culture studies using disks made of same materials and surface as of implants may provide useful information on the events occurring at the implant-tissue interface. In the current study, we tested the hypothesis that there is no difference in the proliferation and differentiation capacities of osteoblastic cells when cultured on titanium disks mimicking the surface of 3M™ESPE™ MDIs or standard (Ankylos®) implants. METHODS: Cells were grown on disks made of the same materials and with same surface texture as those of the original implants. Disks were sterilized and coated with 2% gelatin solution prior to the cell culture experiments. C2C12 pluripotent cells treated with 300 ng/ml bone morphogenetic protein 2 BMP-2 and a stably transfected C2C12 cell line expressing BMP2 were used as models for osteogenic cells. The Hoechst 33258-stained nuclei were counted to assay cell proliferation, while alkaline phosphatase (ALPL) immunostaining was performed to investigate osteogenic differentiation. MC3T3-E1 cells were cultured as model osteoblasts. The cells were differentiated and assayed for proliferation and metabolic activities by Hoechst 33258 staining and Alamar blue reduction assays, respectively. Additionally, cultures were stained by calcein to investigate their mineral deposition properties. RESULTS: Electron microscopy showed greater degree of roughness on the MDI surfaces. Nuclear counting showed significantly higher number of C2C12 cells on the MDI surface. Although immunostaining detected higher number of ALPL-positive cells, it was not significant when normalized by cell numbers. The number of MC3T3-E1 cells was also higher on the MDI surface, and accordingly, these cultures showed higher Alamar blue reduction. Finally, calcein staining revealed that the MC3T3-E1 cells grown on MDI surfaces deposited more minerals. CONCLUSIONS: Although both implant surfaces are conducive for osteoblastic cell attachment, proliferation, and extracellular matrix mineralization, cell proliferation is higher on MDI surfaces, which may in turn facilitate osseointegration via increased ECM mineralization.