• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.536-545
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• 1997

The purposes of this study were to evaluate the degree of cavity cleanliness and to observe cavity wall morphology when root-end retrograde cavity preparation was done with ultrasonics. Root resections were done on 20 extracted human maxillary central incisors after canal filling with gutta-percha, and retrocavities were prepared using a slow-speed round bur as a control, and stainless steel ultrasonic tips of power settings of 2 and 6 ($Miniendo^{TM}$, EIE, SA, USA) as experimentals. The degree of the remaining cavity debris and smear layer, and wall morphology were evaluated under the scanning electron microscope. The results were as follows : Cavity prepared with ultrasonics of either power setting showed significantly less smear layer than did slow-speed preparations (p<0.01). However, there was no significant difference in canal debris (p<0.05). Cavity prepared with ultrasonics showed hatcheted appearance of wall, while slow-speed preparation showed relatively plain one.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.515-524
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• 1998

The purposes of this study were to observe the cavity wall morphology and to evaluate the degree of cavity cleanliness when root-end retrograde cavity preparation was done with ultrasonic diamond instruments. To observe the morphology of retrocavity and to evaluate the degree of cavity cleanliness. root-end resections were done on 20 palatal roots of extracted maxillary first molars after canal filling with gutta-percha. Retrocavities were prepared using either ultrasonic diamond instruments or stainless steel ones of medium power setting of level 6 ($Miniendo^{TM}$, EIE, CA, U.S.A.). Morphology of the cavity. degrees of the remaining canal debris and smear layer were evaluated under the scanning electron microscope. The results were as follows: Cavities prepared with ultrasonic diamond instruments showed scratched appearance of wall, while ultrasonic stainless steel preparation showed hatcheted appearance. Ultrasonic diamond instruments induced more smear layer than stainless steel ones did (p<0.01) in the cavity. However, there was no significant difference in canal debris (p>0.05).

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.273-280
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• 2020

Upon investigating the dental health of teeth and gum, and the cleanliness of the oral cavity of female college students in the early 20's, it was reported to be that the number of cariogenic bacteria was heavily related to the acidity of saliva or ammonia. Also, cariogenic bacteria and ammonia was found out to be related with proteins (p<0.01), and ammonia, the synthetic product of cariogenic bacteria was heavily related to blood and white blood cells (p<0.01). To conclude, the healthiness of teeth was related to the acidity of saliva and ammonia, the healthiness of gum was related to blood, proteins and white blood cells while the oral hygiene was most likely to be related to ammonia. This result matched to the seven oral disease cause analyses of the saliva analysis apparatus (Sill-Ha ST-4910), which implied further utilization of this data to clinical implications. However, this study is limited to young personnel who does not have any chronic or general diseases; therefore further study is required to generalize this study.