PURPOSE: To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS: A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non-quantitatively. RESULTS: All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION: The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.
Acetone ; Ceramics ; Ethanol ; Spectrum Analysis ; Steam ; Ultrasonics

PURPOSE: To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS: A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non-quantitatively. RESULTS: All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION: The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.
Acetone ; Ceramics ; Ethanol ; Spectrum Analysis ; Steam ; Ultrasonics

PURPOSE: To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments. MATERIALS AND METHODS: Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy. RESULTS: Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P < .05) and developed interfacial area ratio (Sdr, P < .018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes. CONCLUSION: Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.
In Vitro Techniques ; Microscopy, Electron, Scanning ; Steel ; Tin ; Titanium ; Ultrasonics

PURPOSE: The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS: 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS: Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17–73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION: Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns.
Crowns* ; Dataset ; Dental Bonding ; Dental Marginal Adaptation ; Dental Porcelain ; Dental Pulp Cavity ; Dental Restoration Failure ; Dentists ; Female ; Follow-Up Studies ; Hot Temperature ; Humans ; Jaw ; Lithium* ; Prospective Studies ; Resin Cements ; Survival Analysis ; Survival Rate ; Tooth ; Tooth Fractures

PURPOSE: . Computer-aided design and manufacturing (CAD-CAM) of implant abutments has been shown to result in surface contamination from site-specific milling and fabrication processes. If not removed, these contaminants can have a potentially adverse effect and may trigger inflammatory responses of the peri-implant tissues. The aim of the present study was to evaluate the bacterial disinfection and cleaning efficacy of ultrasonic reprocessing in approved disinfectants to reduce the microbial load of CAD-CAM abutments. MATERIALS AND METHODS. Four different types of custom implant abutments (total N = 32) with eight specimens in each test group (type I to IV) were CAD-CAM manufactured. In two separate contamination experiments, specimens were contaminated with heparinized sheep blood alone and with heparinized sheep blood and the test bacterium Enterococcus faecium. Abutments in the test group were processed according to a three-stage ultrasonic protocol and assessed qualitatively and quantitatively by determination of residual protein. Ultrasonicated specimens contaminated with sheep blood and E. faecium were additionally eluted and the dilutions were incubated on agar plates for seven days. The determined bacterial counts were expressed as colony-forming units (CFU). RESULTS: . Ultrasonic reprocessing resulted in a substantial decrease in residual bacterial protein to less than 80 µg and a reduction in microbiota of more than 7 log levels of CFU for all abutment types, exceeding the effect required for disinfection. CONCLUSION . A three-stage ultrasonic cleaning and disinfection protocol results in effective bacterial decontamination. The procedure is reproducible and complies with the standardized reprocessing and disinfection specifications for one- or two-piece CAD-CAM implant abutments.