OBJECTIVEThe purpose was to analyze the effects of three sterilization methods (dry heat sterilization, steam sterilization, and chemical sterilization) on the corrosion of dental fissure bur.

METHODS200 dental fissure burs were distributed to 10 groups. Bending strength, elastic modulus, and torsional strength were measured by bending and torsional instrument and calculated with special designed software. Among the three sterilization methods, the steam sterilization group showed the most evident.

RESULTSThe corrosion was most severe in steam sterilization group, followed by chemical sterilization, dry heat sterilization. With the sterilization time increased, bending strength, elastic modulus, and torsional strength decreased respectively. Of the three sterilization methods, the mechanical properties were decreased most evidently by steam sterilization, followed by chemical sterilization and dry heat sterilization.

CONCLUSIONIt is proved that the bending strength, elastic modulus and torsional strength have a tight relationship with the corrosion of dental fissure burs. The corrosion was most severe in steam sterilization group, followed by chemical sterilization, dry heat sterilization. In regards of the corrosive effect, the dry heat sterilization might be the best way to sterilize the dental fissure burs.

Dental Fissures ; Dental High-Speed Equipment ; Dental Instruments ; Steam ; Sterilization

OBJECTIVEThe purpose was to analyze the effects of three sterilization methods (dry heat sterilization, steam sterilization, chemical sterilization) on the corrosion of dental fissure burs.

METHODS100 dental fissure burs were distributed to 10 groups. One was control, the burs in the other 9 groups were treated by dry heat sterilization, steam sterilization, chemical sterilization with 5, 10, 15 cycles respectively. Weight method, scanning electron microscope, micro-hardness measurement were used to analyze the corrosion of dental fissure burs.

RESULTSThe fissure burs gained their weight with cycles of sterilization. 5, 10, 15 cycles of dry heat sterilization, 10, 15 cycles of steam sterilization and 15 cycles of chemical sterilization, the weight of fissure burs were significantly increased (P < 0.05). Scanning electron microscope showed differences on the surfaces of dental fissure burs among the three sterilization groups. After sterilization, spot or partial erosion were seen on the surface of the burs. The steam sterilization groups showed the most evident changes, followed by chemical sterilization groups and dry heat sterilization groups. X-ray energy spectrometer showed the steam sterilization groups had the largest percentage of W, followed by dry heat sterilization groups, chemical sterilization groups and control group. Fe had the opposite trends. Micro-hardness reduced after sterilization. The reduction was most clear in steam sterilization group, followed by chemical sterilization and dry heat sterilization ( P< 0.05). The difference between 5 and 10 times of steam sterilization and 5, 10, 15 times of chemical sterilization were significant difference (P < 0.05). There was no significant difference between 5, 10, 15 times of dry heat sterilization (P > 0.05).

CONCLUSIONThe corrosion is most severe in steamsterilization group, followed by chemical sterilization, dry heat sterilization. Dry heat sterilization shows less corrosion.

Corrosion ; Dental Fissures ; Dental High-Speed Equipment ; Dental Instruments ; Steam ; Sterilization

To obtain the caries experience and, plaque accumulation severity and pit and fissure morphology in first permanent molars in 7-8 children in Wuhan, as a reasonable prediction of caries risk and preventive attention in the future, a convenient sample of five primary schools in the vicinity of the Wuhan University School and Hospital of Stomatology was drawn. Two calibrated examiners orally examined all present grade 2 children in the classroom, using standard caries plaque and tooth morphology criteria. Dental caries was scored at enamel (D(2)) and dentine (D(3)) for tooth and surface level. Independent variables were age, gender and school. Data analysis used analysis of variance and t-test. The sample comprised 1 043 7- and 8-year-olds. The prevalence of dental caries in permanent dentition was 8.7% and in primary dentition, 68.7%. Mean Decayed, Missing, Filled Teeth/S (DMFT/S) scores were 0.11 and 0.14, respectively. Mean dmft/s scores were 2.8 and 5.0. The d-component constituted 75% of the d(3)mft index, while enamel carious lesions constituted 36% of the total number of carious lesions (d(2,3)-component). Prevalence of medium and deep pits and fissures was 84.6%. Prevalence of medium and severe plaque accumulation was 67.4%. Prevalence of dental caries in the deciduous and permanent dentitions of 7- to 8-year-old children was high. Deep pits and fissures in high caries risk children should be sealed.
Child ; China ; epidemiology ; DMF Index ; Dental Caries ; epidemiology ; prevention & control ; Dental Enamel ; pathology ; Dental Fissures ; pathology ; Dental Plaque Index ; Dentin ; pathology ; Dentition, Permanent ; Female ; Humans ; Male ; Molar ; pathology ; Prevalence ; Tooth, Deciduous

AIMCluster analysis was conducted on data from 5,169 United States (U.S.) Arizona children, age's 5-59-months with the goal of delineating patterns of caries in the primary dentition of pre-school children without a priori pattern definitions.

METHODOLOGYCluster analyses were conducted using all data for children ages 0-4 years in aggregate: (1) for all subjects, and (2) for subjects without crowned restored teeth. Each of these two sets of analyses consisted of 8 differently specified cluster analyses as a validation procedure.

RESULTSThe caries patterns identified from the clustering analysis are: (1) smooth surfaces (other than the maxillary incisor), (2) maxillary incisor, (3) occlusal surfaces of first molars, and (4) pit and fissure surfaces of second molars.

CONCLUSIONThe cluster analysis findings were consistent with results produced by multidimensional scaling. These cross-validated patterns may represent resulting disease conditions from different risks or the timing of various risk factor exposures. As such, the patterns may be useful case definitions for caries risk factor investigations in children under 60 months of age.

Arizona ; epidemiology ; Caregivers ; education ; Child, Preschool ; Cluster Analysis ; Cohort Studies ; Dental Caries ; epidemiology ; Dental Enamel ; pathology ; Dental Fissures ; epidemiology ; Educational Status ; Ethnic Groups ; statistics & numerical data ; Female ; Humans ; Incisor ; pathology ; Infant ; Male ; Mandible ; Maxilla ; Molar ; pathology ; Tooth, Deciduous ; pathology