IADR Abstract Archives
Variation in Prismatic and Aprismatic Enamel within and between Human Teeth
Objectives: Develop a novel technique to quantify etch patterns in various regions and types of human teeth.
Methods: 27 extracted human teeth, collected from various dental offices, were disinfected with 10% sodium hypochlorite and stored in a 0.1% thymol solution. All teeth had intact buccal enamel with no restorations or caries, and no evidence of decalcification, fluorosis or enamel defects. The buccal surfaces were cleaned with a pumice slurry and etched with 37% phosphoric acid gel etchant for 15 seconds. The samples were sputter coated with gold for 2 minutes. Two regions of etched enamel in each third of the tooth (incisal, middle, and cervical) were viewed at 1200x magnification with the scanning electron microscope. Using Bioquant Osteo (Nashville, TN) software, the percentage of enamel remaining to total surface area was calculated.
Results: Replicate analyses showed no statistically significant systematic differences; random method errors ranged from 5.9% (cervical region) to 4.2% (incisal region). Two way analyses of variance showed no statistically significant interaction between jaw and tooth type. While there were no between-jaw differences, there were statistically significant differences between tooth types. The middle (p=.046) and incisal (p=.002) regions of the premolars and molars showed greater remaining enamel than the incisors and canines. There also were statistically significant regional differences, with the cervical region showing greater remaining enamel than the middle (difference of 2.6%; p=.015) and incisal (difference of 3.6%; p=.006) regions.
Conclusions: There are quantifiable differences in etch quality between teeth and between regions of teeth, with more prismless enamel and worse quality of etch in the cervical regions, especially of the premolars and molars.
Methods: 27 extracted human teeth, collected from various dental offices, were disinfected with 10% sodium hypochlorite and stored in a 0.1% thymol solution. All teeth had intact buccal enamel with no restorations or caries, and no evidence of decalcification, fluorosis or enamel defects. The buccal surfaces were cleaned with a pumice slurry and etched with 37% phosphoric acid gel etchant for 15 seconds. The samples were sputter coated with gold for 2 minutes. Two regions of etched enamel in each third of the tooth (incisal, middle, and cervical) were viewed at 1200x magnification with the scanning electron microscope. Using Bioquant Osteo (Nashville, TN) software, the percentage of enamel remaining to total surface area was calculated.
Results: Replicate analyses showed no statistically significant systematic differences; random method errors ranged from 5.9% (cervical region) to 4.2% (incisal region). Two way analyses of variance showed no statistically significant interaction between jaw and tooth type. While there were no between-jaw differences, there were statistically significant differences between tooth types. The middle (p=.046) and incisal (p=.002) regions of the premolars and molars showed greater remaining enamel than the incisors and canines. There also were statistically significant regional differences, with the cervical region showing greater remaining enamel than the middle (difference of 2.6%; p=.015) and incisal (difference of 3.6%; p=.006) regions.
Conclusions: There are quantifiable differences in etch quality between teeth and between regions of teeth, with more prismless enamel and worse quality of etch in the cervical regions, especially of the premolars and molars.