PMID- 12886206
OWN - NLM
STAT- MEDLINE
DCOM- 20031027
LR  - 20190711
IS  - 0022-3913 (Print)
IS  - 0022-3913 (Linking)
VI  - 90
IP  - 2
DP  - 2003 Aug
TI  - Effects of acid hydrolysis and mechanical polishing on surface residual stresses 
      of low-fusing dental ceramics.
PG  - 133-42
AB  - STATEMENT OF PROBLEM: Cracks may arise in a ceramic restorative material over 
      time, resulting in sudden fractures at stresses well below the yield stress. 
      PURPOSE: This study evaluated by means of indentation technique the effects of 
      acid hydrolysis and mechanical polishing on the surface residual stresses of 
      low-fusing ceramic materials. MATERIAL AND METHODS: A total of 64 ceramic bars 
      were formed to produce 4 groups of 16 bars each for 4 ceramic materials 
      (Duceram-LFC Dentin, Duceram-LFC Enamel, Finesse Dentin, and Finesse Enamel). 
      Four surface-treatment groups (n=4) were then formed for each of the 4 materials. 
      The 4 surface treatments were control (autoglaze), hydrolysis, glaze/polish, and 
      polish/glaze. A Vickers indenter contacted the Duceram-LFC specimens with a 5-N 
      load and the Finesse specimens with a 3-N load for 10 seconds. Scanning electron 
      microscope (SEM) was used to study surface texture before and after hydrolysis 
      and polishing. Differences in mean crack lengths were analyzed with 1-way 
      analysis of variance and least significant difference test (alpha=.05.) RESULTS: 
      SEM showed obvious surface flaws as a result of hydrolysis on Duceram-LFC Enamel 
      and Dentin specimens. However, statistical analysis of the resulting crack 
      lengths revealed no significant differences between values for the control groups 
      (58.16 +/- 3.88) (53.53 +/- 2.67) and hydrolysis groups (57.11 +/- 4.09) (54.54 
      +/- 3.15) for Enamel (P=.081) and Dentin (P=.093) respectively. When comparing 
      polished groups and nonpolished groups, the mean crack lengths were significantly 
      shorter for polished specimens of Duceram-LFC Enamel (53.76 +/- 3.17), Finesse 
      Enamel (40.56 +/- 3.31), and Finesse Dentin (39.76 +/- 3.81) porcelains compared 
      with their control groups (58.16 +/- 3.88) (43.54 +/- 4.12) (41.19 +/- 3.47), 
      respectively (P<.0001). The mean crack lengths were significantly longer for 
      polished specimens of Duceram-LFC Dentin (59.16 +/- 3.52) porcelain compared with 
      the control group (53.53 +/- 2.67) (P<.0001). CONCLUSION: Within the limitations 
      of this study, hydrolysis did not improve surface residual stresses of 
      Duceram-LFC and Finesse ceramic materials. Mechanical polishing improved surface 
      residual stresses of all materials tested, except Duceram-LFC Dentin porcelain.
FAU - Alkhiary, Yaser M
AU  - Alkhiary YM
AD  - Goldman School of Dental Medicine, Boston University, Mass, USA.
FAU - Morgano, Steven M
AU  - Morgano SM
FAU - Giordano, Russell A
AU  - Giordano RA
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - United States
TA  - J Prosthet Dent
JT  - The Journal of prosthetic dentistry
JID - 0376364
RN  - 0 (Acetates)
RN  - 0 (Composite Resins)
RN  - 0 (Dental Materials)
RN  - 0 (Duceram)
RN  - 12001-21-7 (Dental Porcelain)
RN  - 76363-65-0 (finesse)
SB  - IM
MH  - Acetates/chemistry
MH  - Analysis of Variance
MH  - Ceramics/*chemistry
MH  - Composite Resins/chemistry
MH  - Dental Materials/*chemistry
MH  - *Dental Polishing
MH  - Dental Porcelain/chemistry
MH  - Hardness
MH  - Humans
MH  - Hydrolysis
MH  - Materials Testing
MH  - Microscopy, Electron, Scanning
MH  - Stress, Mechanical
MH  - Surface Properties
EDAT- 2003/07/30 05:00
MHDA- 2003/10/28 05:00
CRDT- 2003/07/30 05:00
PHST- 2003/07/30 05:00 [pubmed]
PHST- 2003/10/28 05:00 [medline]
PHST- 2003/07/30 05:00 [entrez]
AID - S0022391303002774 [pii]
AID - 10.1016/s0022-3913(03)00277-4 [doi]
PST - ppublish
SO  - J Prosthet Dent. 2003 Aug;90(2):133-42. doi: 10.1016/s0022-3913(03)00277-4.