The 5-W power setting may be suitable for dental restoration applications in terms of shear bond strength and activation area.

Purpose:In full mouth reconstructive dentistry, the occlusal vertical dimension(OVD) is often increased to provide adequate restorative space or for esthetic reasons. The purpose of this study was to analyze the effect of occlusal vertical dimension on dimensional measurements of the smile. Materials and Methods:30 dental students, 12 male and 18 female between the ages of 21 -30 participated in this study. Polyvinyl Siloxane bite splints of 2mm, 4mm, 6mm, 8mm thicknesses were fabricated on stone casts mounted on semi-adjustable articulators. A wall-mounted head positioning device, modified from a cephalometric unit was used to stabilize head positions. Three photographs each at OVD of +0mm, +2mm, +4mm, +6mm, +8mm were taken using a DSLR camera mounted on a tripod. Measurements were made in Adobe Photoshop CS5, using the width of the maxillary central incisors to convert pixel measurements to millimeter measurements. Results:One way repeated measures ANOVA found statistically significant differences in interlabial gap height, incisal edge -lower lip length, and display zone area with increasing OVD. No statistically significant differences were found for intercommisural width and incisal edge -upper lip length. Conclusions:This study demonstrates that excessive increase of OVD may lead to excessive interlabial gap height, incisal edge -lower lip length, and display zone area. A lengthening of the upper lip at smile should not be expected with increasing OVD. In addition, a change in the width of the smile should not be expected with increasing OVD. i ACKNOWLEDGEMENTS

No abstract

Changes in occlusal vertical dimension (OVD) and age have been found to affect Smile Index (SI, width/height of smile). Limited information is available regarding the aesthetic effects of these changes. The objective of this study was to evaluate the attractiveness of digitally manipulated smile images with differences in SI and incisal edge position (IEP) judged by respondents in different age groups. A total of 12 smile images were generated with varying SI (3·5, 5·3, 7·2, 9·0) and IEP (High, Medium, Low). Fifty respondents each in four age groups (15-24, 25-39, 40-54, 55+) evaluated the attractiveness of the 12 images using a 0-10 visual analog scale (VAS, 10 being most attractive). A repeated-measures three-factorial mixed model assessed differences. SI, IEP and age of respondents were found to significantly influence attractiveness score (P < 0·01 for all). With all age groups combined, SI = 7·2/IEP = Medium was most attractive (VAS = 7·22), followed by SI = 9·0/IEP = Medium, and SI = 5·3/IEP = Medium (VAS = 6·53 and 6·48, respectively). SI = 3·5/IEP = High and SI = 3·5/IEP = Low were least attractive (VAS = 1·99 and VAS = 2·58, respectively). Age group significantly influenced aesthetic perception, with younger respondents more critical in differences in SI and IEP. SI and IEP significantly influenced attractiveness of the smile in all respondent age groups. Low SI (i.e. 3·5) combined with high or low IEP was unattractive. Medium SI to high SI (i.e. 5·3-9·0) combined with medium IEP were considered attractive.

The aims of this study were to evaluate dental students' clinical shade-matching outcomes (from subjective use of shade guide) with an objective electronic shade-matching tool (spectrophotometer); to assess patients', students', and supervising faculty members' satisfaction with the clinical shade-matching outcomes; and to assess clinicians' support for use of the spectrophotometer to improve esthetic outcomes. A total of 103 volunteer groups, each consisting of patient, dental student, and supervising faculty member at the University of Louisville, were recruited to participate in the study in 2015. Using the spectrophotometer, clinical shade-matching outcome (ΔE) and laboratory shade-matching outcome (ΔE) were calculated. Two five-point survey items were used to assess the groups' satisfaction with the clinical shade-matching outcome and support for an objective electronic shade-matching tool in the student clinic. The results showed that both ΔE (6.5±2.4) and ΔE (4.3±2.0) were outside the clinical acceptability threshold ΔE values of 2.7, when visual shade-matching method (subjective usage of shade guide) was used to fabricate definitive restorations. Characteristics of the patients, dental students, supervising faculty members, and restorations had minimal to no effect on the ΔE The patients, dental students, and supervising faculty members generally had positive opinions about the clinical shade-matching outcome, despite the increased ΔE observed. Overall, clinical shade-matching outcomes in this school need further improvement, but the patients' positive opinions may indicate the need to revisit the acceptability threshold ΔE value of 2.7 in the academic setting.