ABSTRACT
Many longitudinal studies have reported the successful osseointegration of dental implants, with survival rates approaching 90-95%. However, implants regarded as a "success" may have also failed to undergo osseointegration. A variety of complications and failures have been observed, including implant fracture - a rare and delayed biomechanical complication with serious clinical outcomes. Given the increasing popularity of dental implants, an increase in the number of failures due to late fractures is expected. This study sought to determine the rate of implant fractures and factors associated with its development. This retrospective evaluation analyzed implants placed at Wonkwang Dental Hospital (from 1996 to the present). In our study we found that the frequency of dental implant fractures was very low (0.23%, 8 implant fractures out of 3,500 implants placed). All observed fractures were associated with hybrid-surface threaded implants (with diameter of 4.0 or 3.75 mm). Prosthetic or abutment screw loosening preceded implant fracture in a majority of these cases.
Subject(s)
Dental Implants , Electrons , Osseointegration , Retrospective Studies , Survival RateABSTRACT
Objective:To evaluate the ability of calcium hydroxide removal using different irrigation methods and the effect on canal sealing.Methods:200 human single root canal premolar teeth were prepared.Divided the teeth randomly into 2 groups(each group 96 teeth,8 as control),one group filled with chemical calcium hydroxide and another filled with finished product calcium hydroxide.7 days after,divided each groups randomly into 6 subsets and remove the calcium hydroxide in the root canal(table1).Then each subset group choose 8 teeth randomly,observed by scanning electron microscope.Other specimens were obturated by lateral condensation of cold gutta-percha with a AH-Plus sealer,stained by Indian ink and then made into transparent teeth model.Results:At the same condition,there was no significant difference between group A and group B;the results of groups associated with ultrasonic were better than groups with injection syringe.The rinse solution EDTA was the best,distilled water was the worse.Dye penetration showed that the length of dye staining was no significant difference among all groups.Conclusion:Ultrasonic and sodium hypochlorite associate EDTA is the best method to remove the calcium hydroxide.But none of the methods and rinse solution used in this experiment can remove all of the calcium hydroxide.The calcium hydroxide remained influence on the root canal sealer is not predominance.
ABSTRACT
Objective:To investigate the effect of self-made herbal desensitizer in the treatment of dentine hypersensitivity. Methods:Herbal desensitizer was made of corydalis tuber, asarum herb, long pepper, galangal rhizom and prepared wild aconite root into three different forms:gargle(GG), embrocation(EC) and cataplasm(CP). 750 g/L sodium fluoride paste(SFP) was used as the control. 765 teeth with dentine hypersensitivity in 216 patients were treated with GG,CP,EC and SFP respectively at random. In group CP dental tray was used to carry the desensitizer.The clinical effects were observed in the following 6 months. The effects of the drugs on the obstruction of detinal tubules were observed with scanning electron micoscope(SEM) in the in vitro experiment on 12 extracted teeth.Results:The clinical immediate effective rate(%)of GG,CP,EC and SFP was 57.3(110/192),91.8(179/195),86.9(166/191) and 63.6(119/187) (CP vs GG,EC or SFP P
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Objective:To evaluate the effect of retrograde preparation by using slow-speed handpiece or by ultrasonic tips.Methods:Forty-eight extracted premolars were inspected with Scanning Electron Microscope for the minimum dentine thickness recorded after preparation of root-end cavities by low-speed handpiece and ultrasonic instrument respectively.Results:By using slow-speed handpiece,the minimum dentine thickness recorded after the preparation of root-end cavities was 0.15 mm;whereas that was 0.82 mm and 0.76 mm by ultrasonic instrument with S12 9D and S12 9 respectively(handpiece vs ultrosonic instrument,P
ABSTRACT
A 37-year-old male with localized trichorrhexis nodosa on the scalp is described. Two circumscribed broken hair patches that had occurred as a consequence of repetitive friction trauma were seen on both retroauricular areas of scalp. Scanning electron microscopic findings revealed typical trichorrhexis nodosa.