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Browsing by Author "Diefenderfer, Kim Edward"
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Item Influence of dentrifice abrasivity and toothbrush stiffness on the development of non-carious cervical lesions(2016) Binsaleh, Fahad; Hara, Anderson T.; Lippert, Frank; Bottino, Marco; Cook, Norman Blaine; Diefenderfer, Kim EdwardBackground: Non-carious cervical lesions (NCCLs) can be defined as the loss of dental hard tissue near the cemento-enamel junction without bacterial involvement. Abrasion, erosion and abfraction have been mentioned as common etiological factors of NCCLs. Abrasion is the loss of tooth structure due to friction by materials such as toothbrushes or abrasives in toothpaste. In contrast, dental erosion is the loss of tooth structure driven by acids. Abfraction, on the other hand, starts due to the weakening of the tooth structure in areas of concentrated stress as a result of cuspal flexure from heavy and repeated occlusal loading, which progresses to dental hard-tissue loss. Purpose: The present study focused on the abrasion aspect of NCCLs. Specifically, it aimed to investigate the influence of dentifrice abrasivity and toothbrush stiffness on the development of NCCLs in vitro Hypothesis: NCCL development is affected by both the abrasive level of the dentifrice and the stiffness of the toothbrush, as well as their interaction. Materials and Methods: A total of 288 extracted human upper first premolars, free of any dental caries and root defects, were selected. The teeth were be cleaned with a hand periodontal scaler and randomly assigned into twelve groups (total of 24 teeth/group). Specimens were brushed in an automated toothbrushing machine, using simulated toothpaste slurries of varying abrasivity and toothbrushes of varying stiffness. This study examined three experimental factors: 1. Toothpaste abrasivity, at four levels: high, medium, low, and non-abrasive slurry (as negative control); 2. Toothbrush stiffness, at three levels: soft, medium, and hard; 3. Toothbrushing cycles at three levels: baseline, 35k, and 65k strokes. Specimens were analyzed by optical profilometry at baseline and after each brushing level. The response variable was the dentin volumetric loss, in mm3. All toothbrushes caused significantly higher tooth wear when associated to the high abrasive slurry, compared to medium- and low-abrasive slurries. Medium- caused more tooth wear than low-abrasive slurry, which in turn led to more tooth wear than the control. Hard and medium toothbrushes were not significantly different, but both caused significantly higher volumetric loss than Soft toothbrushes. There were no differences among toothbrushes, when used with the non-abrasive (control) and low- abrasive slurries. Overall, 35k strokes resulted in significantly less tooth volumetric loss than 65k.Item Performance of near infared digital imaging transillumination for detection of non-cavitated approximal caries(2016-06-01) Abogazalah, Naif Nabel Fouad; Ando, Masatoshi; Diefenderfer, Kim Edward; Platt, Jeffrey A.; Hara, Anderson T.; Cook, Norman BlaineObjective: The objectives of this in-vitro study were: 1) to evaluate the ability of Near-Infrared Digital Imaging Transillumination (NIDIT) to detect non-cavitated approximal caries lesions; and 2) to compare the performance among NIDIT, Digital Radiography (DR), Digital Imaging Fiber-Optic Trans-Illumination (DIFOTI) and International Caries Detection and Assessment System (ICDAS). Methods: Thirty human extracted premolars were selected. The approximal surface status ranged from sound to surfaces with non-cavitated caries lesions into the outer one-third of the dentin. Lesion depth was determined by micro-computed tomography (μ-CT) and used as a gold standard. Teeth were mounted in a custom-made device to simulate approximal contact. ICDAS, DR, DIFOTI and NIDIT examinations were performed and repeated by three trained and calibrated examiners. Sensitivity, specificity, area under ROC curve (Az), inter- and intra-class correlation coefficients (ICCs) of each method, and correlation among the methods were determined. Results: ICCs for intra-/inter-examiner agreement were almost perfect for DIFOTI (0.85/0.83), substantial for ICDAS (0.79/0.72) and NIDIT (0.69/0.64), and moderate for DR (0.52/0.48). Sensitivity/specificity for DIFOTI, ICDAS, DR, and NIDIT were 0.91/0.69, 0.89/0.83, 0.50/0.64, and 0.68/0.93, respectively. Az of DR (0.61) was significantly lower than that of DIFOTI (0.91, p = 0.002) and ICDAS (0.90, p = 0.005), but was not significantly different from NIDIT (0.81, p = 0.052). DIFOTI, ICDAS, and NIDIT were not significantly different from each other (p > 0.13). Spearman correlation coefficients for DIFOTI (0.79, p < 0.001), ICDAS (0.74, p < 0.001), and NIDIT (0.65, p < 0.001) demonstrated a moderate association with μ-CT, while that of DR suggested no association (0.19, p = 0.289). Conclusion: Within the limitations of this in-vitro study, NIDIT system demonstrated a potential for early approximal caries detection. ICDAS, DIFOTI, and NIDIT were superior to DR in terms of validity and reliability.