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Statement of Problem: Consideration of the thickness of alveolar bone on both the palatal and labial sides and the inclination angle of teeth is important for immediate implant placement in the maxillary anterior region. However, comprehensive research exploring how sex and age influence the thickness of bone and tooth angle in the maxillary anterior region is lacking., Purpose: The purpose of this clinical study was to investigate the effect of sex and age on the thickness of labial and palatal bone and on the tooth inclination angle of maxillary central and lateral incisors using cone beam computed tomography (CBCT) images in an Asian population., Material and Methods: The labial and palatal bone thickness and the inclination angle of maxillary central and lateral incisors were measured from the CBCT images of 149 participants aged between 20 and 65 years. The correlation between the angles of the maxillary central and lateral incisors and sex and age on the tooth angles and thicknesses of labial and palatal bone was determined statistically., Results: A high correlation (R=0.73) was found between the angle of maxillary central and lateral incisors. Men had higher angles of the maxillary central and lateral incisors and thicker palatal bone at the middle and root of the teeth compared with women. In both sexes, the angle and palatal bone thickness of maxillary central incisors were significantly higher than those of maxillary lateral incisors. The angle of both maxillary central and lateral incisors decreased gradually with age, with a difference in angle of over 10 degrees., Conclusions: The study revealed that women exhibited relatively thinner palatal bone compared with men. Additionally, participants aged between 40 and 65 years exhibited significantly thicker palatal bone compared with younger age groups, potentially providing a larger site for implant placement. Furthermore, tooth angle gradually decreases with age in the maxillary anterior region., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The recurrent esthetic dental (RED) proportion has been a benchmark for the rehabilitation of the maxillary anterior teeth of North American patients. While it has been evaluated in other populations, the global application of RED proportions in the rehabilitation of maxillary anterior teeth is unclear., Purpose: The purpose of this systematic review was to examine the existing evidence on dental proportion to evaluate the existence of RED proportions in the esthetic smile in different geographic regions., Material and Methods: A systematic search was conducted by reviewing different databases. The focused question was "Does RED proportion exist in esthetically pleasing smiles in different populations around the world?" The search included articles with a combination of MeSH keywords based on dental proportion from January 2000 to July 2020. The titles and abstracts were identified by using a search protocol. Full text of the articles was independently evaluated. The systematic review was modified to summarize the relevant data. The general characteristics, outcomes, and quality of studies were reviewed and analyzed systematically., Results: Seventeen studies were selected from the reviewed articles. Three studies were conducted in Europe, 10 in South Asia, and 4 in Western Asia. Eleven studies found that the mean perceived ratio of anterior teeth was not constant when progressing distally. Five studies reported that the ratio was constant in a small percentage of their populations, and 1 suggested that the ratio was constant if it remains between 60% and 80%. The central-to-LI and Ca-to-LI proportion values were not constant. Overall, the Ca-to-LI proportion values were higher than the central-to-LI proportions., Conclusions: RED proportions were not found in the successive widths of maxillary anterior teeth among the reviewed data from different geographic regions. RED proportions are not the only standard for restoring esthetic smiles worldwide, and anterior tooth proportions differ among populations based on their race and ethnicity., (Copyright © 2021 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Clinicians and dental technicians may underestimate what is deemed esthetic by laypersons and dental professionals., Purpose: The purpose of this study was to define the relative importance of symmetry, visual tension, and balance in the smile., Material and Methods: Images of a white woman were altered to reproduce symmetry, various visual tensions, distinct tooth shapes, and color changes. A 12-question survey was presented to 128 individuals, including 81 dental professionals and 47 laypersons. The survey asked individuals to choose the most desirable and beautiful image in a choice of images., Results: Raters were most influenced by the maxillary central incisors and then the canines and were more forgiving on visual tensions of the maxillary lateral incisors. Square-shaped teeth were preferred over ovoid and triangular ones. The more upright the canines, the more the smile was perceived as masculine. Teeth whiter than the sclera of the eyes were preferred, with lay individuals choosing the lightest shade available and dental professionals choosing the shade slightly lighter than the sclera. Although participants mostly preferred a symmetrical smile, they opted for the natural face as opposed to symmetrical ones., Conclusions: Location of visual tension plays a role in perceiving beauty. Symmetrical smiles were considered more pleasant but not symmetrical faces. Imperfections play an essential role in perceiving beauty because they express life, individuality, charisma, and charm., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Comprehensive studies evaluating the dimensions of anterior maxillary teeth in the Turkish population with respect to different esthetic parameters are lacking., Purpose: The purpose of this clinical study was to evaluate different proportions of teeth and compare them with current esthetic parameters such as the golden proportion, recurring esthetic dental proportion, and width-to-height ratio of central incisors and to evaluate whether the apparent contact dimension of maxillary anterior teeth follows the "50:40:30" rule., Material and Methods: A total of 150 Turkish dental students (81 men and 69 women) aged between 18 and 24 years participated in the study. Standardized digital photographs of the mouth were made from an anterior view. The width and length of the maxillary central incisor, apparent width of the maxillary lateral and canine teeth, and distances between contact areas of the maxillary incisor teeth were measured with software. Differences between the measured proportions and the determined esthetic parameters were assessed with the 1-sample t test (α=.05)., Results: The width and length proportions of the maxillary incisor teeth in both sexes were significantly different than the golden and recurring esthetic dental proportions. The width-to-height ratio for the maxillary central incisor was different from 80%, which is considered optimal, and the difference among these parameters was statistically significant (P<.001). The apparent contact dimensions on the right and left sides were not statistically significantly different (P>.05). However, the proportions did not fit the 50:40:30 ratio that has been defined as the esthetic proportion, and the differences were statistically significant (P<.001)., Conclusion: Proportions among maxillary anterior teeth were found to be significantly different from the golden proportion and recurring esthetic dental proportion in both sexes. The proportions of apparent contact dimension were significantly different than the 50:40:30 ratio in both sexes. The width-to-height ratio for maxillary central incisor was significantly different from 80% in both sexes., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Dentists providing anterior restorations are guided by the principles of anatomic tooth dimension. Dental biometrics should consider ethnicity to produce a more comprehensive evaluation., Purpose: The purpose of this clinical study was to analyze the anatomic crowns of maxillary central incisors (CI), lateral incisors (LI), and canines (C) with respect to the golden proportion (GP) and width/height (W/H) ratio in Kurdish and Arab populations., Material and Methods: Maxillary gypsum casts were obtained from 100 participants (50 from a Kurdish and 50 from an Arab population). Standardized digital photographs of each cast were recorded. The apparent and actual anterior tooth dimensions were determined by ImageJ software for the calculation of the GP and W/H ratio. Data were statistically analyzed using ANOVA to investigate ethnic, sex, and arch side differences. The chi-square test was used to explore the GP, and the 1-sample t test was used to test the ideal W/H ratio (α=.05)., Results: The GP was found in both the Kurdish and Arab groups in the LI/CI mean (0.62, 0.63), but not in the C/LI mean (0.69, 0.73). No difference due to sex was detected in the LI/CI in either ethnic group, but Kurdish men had significantly larger C/LI than women (0.73, 0.66, P=.006) and larger right-side LI/CI than left (0.63, 0.60, P=.049). The W/H ratio was higher than the predicted ideal ratio of 80% (range, 88% to 90%). The LI W/H ratio in Arabs was significantly larger than in Kurds (90.3% versus 82.7%, respectively; P<.001)., Conclusions: The GP was found to exist between the apparent widths of maxillary anterior teeth LI/CI for the both populations in both men and women but not for C/LI. No ideal ratio was detected for the W/H ratios. Specific population characteristics must be taken into consideration, especially when applying the proportions to Kurdish individuals., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Various methods have been suggested for determining the width of maxillary anterior teeth for complete dentures. A straightforward and reliable technique for anterior tooth selection in complete denture is still needed., Purpose: The purpose of this clinical study was to determine the correlation between the horizontal visible iris diameter (HVID) of the eye and the mesiodistal width of the maxillary central incisor tooth in a dentate Indian population., Material and Methods: One hundred Indian dental students participated in this study. A standardized image of the face revealing the eyes and teeth on smile was captured. The measurements of the HVID and the mesiodistal width of the maxillary central incisor at the cervical third, middle third, and incisal edge were evaluated with photoimaging software. The data were subjected to statistical analysis by paired-sample t test to compare the right and left sides, independent-sample t tests to compare between sexes, and the Pearson correlation coefficient (r) to investigate the association between variables (α=.05) RESULTS: A positive correlation between the HVID and the mesiodistal width of the maxillary central incisor was found in men, with r values of .62, .78, and .79 in the cervical, middle, and incisal third regions, respectively. In women, respective r values of .59, .73, and .75 were found. Minimal differences were observed between right- and left-side measurements., Conclusions: The HVID of the eyes can be used to estimate the mesiodistal width of the maxillary central incisor tooth., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: As the cosmetic demands of patients increase, determining the appropriate dimensions of the maxillary anterior teeth has become increasingly relevant. The relationship between facial measurements and tooth size provide guidance for maxillary anterior tooth size selection. However, most publications on this topic have focused on the white population, and more data for tooth sizes and their proportions in other ethnicities are needed., Purpose: The purpose of this observational study was to investigate the relationship between the mesiodistal dimensions of the 6 maxillary anterior teeth and the bizygomatic width, interpupillary distance, intercanthal distance, interalar width, and intercommissural width of individuals of Asian, African-American, and white ethnicities., Material and Methods: Standardized digital images of 360 participants (120 Asian, 120 African-American, and 120 white) were used to measure facial segments. Individual dimensions of the 6 maxillary anterior teeth were measured using stone casts with digital sliding caliper. The combined width of the 6 maxillary anterior teeth on a straight line corresponded to the sum of the anterior tooth width. The means and standard deviations from descriptive measurements were calculated and analyzed for face and maxillary anterior tooth ratios and correlations. Statistical analysis was done using the Kruskal-Wallis procedure to compare facial and tooth parameters among the 3 ethnicities. Appropriate post hoc comparisons that adjusted for multiple testing were conducted when warranted (α=.05). The Spearman rho correlation, a nonparametric correlate of the Pearson correlation, was used to associate the facial and tooth parameters within the strata of sex and ethnicity., Results: No consistent ratios were found among the examined facial dimensions and the mesiodistal dimensions of the 6 maxillary anterior teeth among the 3 ethnicities, except for the central incisor width-to-bizygomatic width ratio. No correlations were found between the facial dimensions and mesiodistal dimensions of the 6 maxillary anterior teeth among the 3 ethnicities except in Asian women. For Asian women, the intercommissural width correlated with the width of the central incisor (P=.001), the width of 2 central incisors (P=.001), the width of 4 incisors (P=.003), and the width of 6 maxillary anterior teeth (P=.005)., Conclusions: No facial proportions by which the exact width of maxillary anterior teeth could be predicted were found in Asian, African-American, or white populations., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Dentists frequently use electronic devices to determine tooth color. However, neither the instructions for these devices nor the accompanying brochures refer to the environmental conditions required at the point of measurement., Purpose: The purpose of this multicenter prospective clinical study was to reveal whether a change in the oral background influences tooth color determination., Material and Methods: Students (N=42) at the dental clinic in Berlin, Leipzig, Greifswald and Olomouc (women n=27, men n=15) participated in this study. It was their first contact with the spectral photometer (Easyshade Advance 4.0; VITA Zahnfabrik). After a short introduction on how to use the device, the students made 1-point measurements on the same patient on the maxillary central incisor. In the first measurement, the patient's mouth was open, and the palatal surface uncovered. In the second measurement, the patient's mouth was closed slightly, and the tongue pressed on the lingual surface of the maxillary central incisor. The mean ±SD and the 95% confidence interval (95 % CI) were calculated using the Student t test for each test series (α=.05)., Results: Statistical evaluation of the 2 measurements revealed changes in the L*a*b* values with a mean L*=0.204, a*=-0.351, and b*=0.02; a median of 0.4, -0.3, and -0.1, respectively; a ±SD of 2.37, 0.64, and 0.89, respectively; and 95% CIs of L*=-0.476 to 0.884, a*=-0.531 to -0.702, and b*=-0.23 to 0.52, respectively. These differences were not statistically significant (P>.05). The measurements of L*, a*, and b* with and without tongue coverage of the lingual surfaces of the maxillary teeth did not show any statistically significant differences (P=.663)., Conclusions: The results demonstrate that the position of the tongue does not influence measurement accuracy during the application of the Easyshade Advance device., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Few studies have investigated the colorimetric distribution of gingival color, including the posterior area and alveolar mucosa., Purpose: The purpose of this in vivo study was to investigate the distribution of colorimetric values in different areas of gingiva and to determine its relationship to colorimetric findings of the tooth and skin in a young Korean population., Material and Methods: Participants included 40 periodontally healthy adults (22 men and 18 women) 25 to 36 years of age. Commission Internationale de l'Eclairage values (CIELab: L* lightness, a* green-red, and b* blue-yellow) were measured using a colorimeter at a total of 23 sites for each participant, including attached gingiva (AG) and alveolar mucosa (AM) in the maxillary and mandibular and incisor and molar regions, maxillary central incisor, and skin points of the glabella, cheek, and inner upper arm., Results: AG showed higher L* and lower a* values than AM. AG demonstrated higher L* and lower a* values in the maxillary region than in the mandibular region and higher b* values in the incisor region than in the molar region. AM revealed higher L* and lower a* and b* values in the incisor region than in the molar region. Positive significant correlations were found for L* between the skin area and AM and for b* between the skin area and AG., Conclusions: The colorimetric values of AG and AM differ according to the area, possibly as a result of differences in anatomic and histologic distribution that influence optical properties., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: No universally accepted parameter exists for selecting maxillary central incisors (MCIs) relative to facial proportions., Purpose: The purpose of this prospective clinical study was to determine the relationship between MCIs and facial height and width in adults, intersex differences, and measurement differences between right and left MCI., Material and Methods: A prospective study was undertaken of 149 dental students (F:76; M:73) aged between 18 and 30 years. Anthropometric MCI and horizontal and vertical facial measurements were recorded with digital calipers by 1 operator. Correlation was investigated with Pearson correlation coefficients (α=.05). Two-sample t tests were used for intersex comparisons and paired t tests to compare right and left MCIs. Intraexaminer reliability was tested by remeasuring 25 participants and applying the Bland-Altman and Lin analyses., Results: The mean MCI height was 10.28 mm (right and left) and the mean widths were 8.65 mm (right) and 8.66 mm (left). Intersex incisor differences existed for height measurements (M:F 0.54 mm [right], 0.46 mm [left]) and width measurements (M:F 0.26 mm) but not for width-to-height ratios (F=0.85; M=0.84). A mean ratio of 15.56 was found between bizygomatic width:tooth width (M=15.75, F=15.37) and of 17.93 between total face height:MCI height (M=17.97, F=17.89). Correlation coefficients were low for all tooth:face measurements. Intraexaminer reliability was clinically acceptable., Conclusions: Men had larger teeth and faces but similar width:height ratios. There was no significant size difference between right and left MCI, little individual relationship between tooth:face proportions, and insignificant sex influence. The "biometric ratio"' of 1:16 for MCI:bizygomatic width was not reconfirmed exactly. A ratio of 1:18 is proposed for MCI height to total face height (Tr-Me') and 1:12 for face height (N'-Me')., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: One of the most difficult aspects of complete denture fabrication is selecting appropriately sized maxillary anterior teeth that will harmonize with the face. There are no generally accepted or naturally observed principles to guide dentists in this selection., Purpose: The purpose of this study was to determine whether a relationship exists between various facial measurements and the different single or combined mesiodistal widths of maxillary anterior teeth in a Kurdish population., Material and Methods: A total of 65 Kurdish dental students participated in this study. Two standardized digital photographs of the face (relaxed and smiling capture) were recorded. The interpupillary distance (IPD), inner canthal distance (ICD), interalar distance (IAD), and width of the 2 central incisors were determined by Image J software. The mesiodistal width and the combined straight-line width of the centrals, laterals, and canines were measured directly from the casts of the participants with digital calipers. A simple linear regression and the Pearson correlation coefficient were used to investigate the relationship between the particular facial measurement and the widths of the anterior teeth (α=.05)., Results: Significant correlations existed between the IPD and different tooth measurements; the highest was with the mean width of the canines (r=0.55). The proposed proportion between the IPD and the central incisor width was 6.93. The golden proportion of the ICD to the width of the central incisors and of the IAD to the straight-line width of the 6 anterior teeth could be used as a dependent parameter in Kurdish men., Conclusions: The IPD can be used to predict the width of anterior teeth in both sexes. In men, the width of the central incisors may be estimated from the ICD and the straight-line width of the 6 anterior teeth from the IAD., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Agenesis of the maxillary lateral incisor has been linked to differences in the size of the remaining teeth. Thus, the mesiodistal space required for definitive esthetic restoration in patients with missing maxillary lateral incisors may be reduced., Purpose: The purpose of this study was to determine whether a tooth size discrepancy exists in orthodontic patients with agenesis of one or both maxillary lateral incisors., Material and Methods: Forty sets of dental casts from orthodontic patients (19 men and 21 women; mean 15.9 years of age; all of European origin) were collected. All casts had agenesis of one or both maxillary lateral incisors. Teeth were measured with a digital caliper at their greatest mesiodistal width and then compared with those of a control group matched for ethnicity, age, and sex. Four-factor ANOVA with repeated measures of 2 factors was used for statistical analysis (α=.05)., Results: Orthodontic patients with agenesis of one or both maxillary lateral incisors exhibited smaller than normal tooth size compared with the control group. The maxillary arch had a larger tooth size difference between the control and test groups than the mandibular arch (there was a significant Jaw × Group interaction [F=4.78, P=.032])., Conclusions: Agenesis of one or both maxillary lateral incisors is significantly associated with tooth size discrepancy, which may affect the space remaining for restoration of the remaining teeth., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The Kois Dento-Facial Analyzer System (KDFA) is used by clinicians to mount maxillary casts and evaluate and treat patients. Limited information is available for understanding whether the KDFA should be considered as an alternative to an earbow., Purpose: The purpose of this study was to evaluate maxillary casts mounted using the KDFA with casts mounted using Panadent's Pana-Mount Facebow (PMF). Both articulation methods were compared against a lateral cephalometric radiograph., Material and Methods: Fifteen dried human skulls were used. Lateral cephalometric radiographs and 2 maxillary impressions were made of each skull. One cast from each skull was mounted on an articulator by means of the KDFA and the other by using the PMF. A standardized photograph of each articulation was made, and the distance from the articular center to the incisal edge position and the occlusal plane angle were measured. The distance from condylar center to the incisal edge and the occlusal plane angle were measured from cephalometric radiographs. Finally, the 3-dimensional position of each articulation was determined with a Panadent CPI-III. A randomized complete block design analysis of variance (RCBD) and post hoc tests (Tukey-Kramer HSD) (α=.05) were used to evaluate the occlusal plane angle and axis-central incisor distance. A paired 2-sample t test for means (α=.05) was used to compare the X, Y, and Z distance at the right and left condyle., Results: The KDFA and PMF mounted the maxillary cast in a position that was not statistically different from the skull when comparing the occlusal plane angle (P=.165). Both the KDFA and the PMF located the maxillary central incisor edge position in a significantly different position compared with the skull (P=.001) but were not significantly different from each other. The 3-dimensional location of the maxillary casts varied at the condyles by approximately 9 to 10.3 mm., Conclusion: The KDFA mounted the maxillary cast in a position that was not statistically different from the PMF when comparing the incisal edge position and the occlusal plane angle. Both the KDFA and the PMF located the maxillary incisal edge position in a significantly different position compared with the anatomic position on dried human skulls., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Determining the retention and resistance of a tooth preparation for a complete crown has only existed in theory, and these theories have never been measured on tooth preparations performed in vivo., Purpose: The purpose of this study was to measure the theoretical retention and resistance of clinically produced complete crown preparations by using an objective measuring method., Material and Methods: Stone dies from 236 complete crown preparations were collected from dental laboratories. The dies were scanned and analyzed with the coordinate geometry method. Cross-sectional images were captured, and the surface area was measured with a cone frustum and right truncated pyramid formula. Two different theories of resistance form, the "on" or "off" theory (limiting taper) and the linear model (resistance length), were calculated for premolar and molar preparations., Results: The mean surface areas ranged from 33.97 mm(2) to 105.44 mm(2) for the cone frustum formula and 41.75 mm(2) to 117.50 mm(2) for the right truncated pyramid formula. The facial side of maxillary premolars exhibited the highest percentage of resistance form with the limiting taper, at 58%, and the mesial side of the mandibular molars exhibited the lowest percentage of resistance form, at 6%., Conclusions: The objective method used in this study provides a way for retention and resistance theories to be tested and for further clinical implications to be investigated., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: An implemented objective measuring system for measuring clinical tooth preparations does not exist., Purpose: The purpose of this study was to compare clinically achieved tooth preparations for ceramic crowns by general dentists with the recommended values in the literature with an objective measuring method., Material and Methods: Two hundred thirty-six stone dies prepared for anterior and posterior complete ceramic crown restorations (IPS e.max Press; Ivoclar Vivadent) were collected from dental laboratories. The dies were scanned and analyzed using the coordinate geometry method. Cross-sectioned images were captured, and the average total occlusal convergence angle, margin width, and abutment height for each preparation was measured and presented with associated 95% confidence intervals., Results: The average total occlusal convergence angles for each tooth type was above the recommended values reported in the literature. The average margin widths (0.40 to 0.83 mm) were below the minimum recommended values (1 to 1.5 mm). The tallest preparations were maxillary canines (5.25 mm), while the shortest preparations were mandibular molars (1.87 mm)., Conclusions: Complete crown preparations produced in general practice do not achieve the recommended values found in the literature. However, these recommended values are not based on clinical trials, and the effects of observed shortfalls on the clinical longevity of these restorations are not predictable., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Restorative dentistry often involves correcting tooth size discrepancies. Therefore, dental biometrics should play an important role in the planning of an esthetic restoration., Purpose: The purpose of this study was to analyze the clinical crown width, length, and width/length ratio of maxillary central incisors, lateral incisors, and canines in an adult population. The study also aimed to determine whether a correlation exists between natural tooth dimensions and the optimal tooth dimension guidelines suggested for planning esthetic restorations., Material and Methods: Stone casts were poured from irreversible hydrocolloid impressions of 412 healthy adult participants. These casts were used to measure the maximum mesiodistal width and maximum crown-root length of the maxillary central incisors, lateral incisors, and canines with a digital precision caliper (0.01 mm). The width/length ratio was calculated for each tooth, and 40 casts were selected to test the reliability of the measuring method., Results: The mean age of the participants in the sample was 33.94 years; 60.7% were women and 39.3% were men. The mean width value was 8.71 mm for central incisors, 6.75 mm for lateral incisors, and 7.81 mm for canines. The mean length was 10.23 mm for central incisors, 8.59 mm for lateral incisors, and 9.93 mm for canines. The average width/length ratio was 85% for central incisors and 79% for lateral incisors and canines., Conclusion: The data obtained from the population studied are similar to those from previous research studies with similar methodology. However, great discrepancies in the absolute values were found when compared with other studies of ideal tooth dimension guidelines on the personal preferences and the esthetic perception of dentists. The perception of what is considered natural seems to differ from what is considered esthetically perfect., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The 3D-Master System comprises 26 physical shade tabs and intermediate shades. Determining the relationship among all the groups of lightness, chroma, and hue of the 3D-Master System (Vita Zahnfabrik) and the L*, C*, and h* coordinates is important, because according to the manufacturer, 2 Toothguide 3D-Master shades need to be mixed in a 50:50 ratio to create an intermediate shade., Purpose: The purpose of the study was to relate the lightness, chroma, and hue groups of the 3D-Master System with the polar coordinates of the CIELAB chromatic space, L*, C*, and h*, and to quantify the shades tabs and intermediate shades of the 3D-Master System according to color coordinates., Material and Methods: The middle third of the facial surface of a natural maxillary central incisor was measured with an Easyshade Compact spectrophotometer (Vita Zahnfabrik) in 1361 Spanish participants aged between 16 and 89 years. Natural tooth color was recorded in the 3D-Master nomenclature and in the CIE L*, C*, and h* coordinates system. The program used for the present descriptive statistical analysis of the results was SAS 9.1.3., Results: In the L* variable, the minimum was found at 47.0 and the maximum at 91.3. In the C* variable, the minimum was found at 5.9 and the maximum at 49.8, while for h*, the minimum was 67.5 degrees and the maximum 112.0 degrees., Conclusions: Despite the limitations of this study, the 3D-Master System was found to be arranged according to L*, C*, and h* coordinates in groups of lightness, chroma, and hue. The corresponding groups of lightness, chroma, and hue can be estimated on the basis of L*, C*, and h* coordinates., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of the Problem: The outline shapes of the dental arch, face, and tooth are esthetic factors used to determine the proper form of artificial teeth when selected for artificial prostheses., Purpose: The purpose of this study was to investigate the quantitative relationships between the outlines of the face, the maxillary central incisor, and the maxillary arch by using Fourier analysis., Material and Methods: Frontal facial photographs and irreversible hydrocolloid impressions of the maxilla were obtained from 200 young, dentate individuals (100 men, 100 women) ages 22 to 28 years. On the resultant casts, standardized photographs were made for the dental arch and the maxillary central incisor. The outlines of the face, dental arch, and tooth were digitally traced and the digitized curved outlines were converted into X-Y coordinates with special software, which, in turn, were imported into Fourier Shape Descriptor software for harmonic analysis. The quantitative outputs of Fourier analyses were analyzed and tested with statistical software to investigate the differences across the shapes of the 3 outlines under study., Results: Facial and tooth outlines were similar for each sex, although the similarity was stronger among the men. By contrast, no relationship was found between tooth and maxillary arch outlines or between face and maxillary arch outlines., Conclusions: Face and tooth forms were quantitatively related. Therefore, face form may reliably guide the selection of artificial anterior tooth form in complete denture prostheses or any complex anterior restorations., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Color errors associated with current shade guides and problems with color selection and duplication are still challenging for restorative dentists., Purpose: The purpose of this study was to evaluate an optimized shade guide for visual shade duplication., Material and Methods: Color distributions (L*, a*, and b*) of the maxillary left central incisors of 236 participants, whose ages ranged from 20 to 60, were measured with a spectrophotometer. Based on this color map, an optimized shade guide was designed with 14 shade tabs evenly distributed within the given color range of the natural incisors. The shade tabs were fabricated with porcelain powder mixtures and conventional laboratory procedures. A comparison of shade duplication by using the optimized and Vitapan Classical shade guides was conducted. Thirty Chinese participants were involved, and the colors of the left maxillary incisors were selected by using 2 shade guides. Metal ceramic crowns were fabricated according to the results of the shade selection. The colors of the shade tabs, natural teeth, and the ceramic crowns were measured with a spectrophotometer. The color differences among the natural teeth, the shade tabs, and the corresponding metal ceramic crowns were calculated and analyzed (α=.017)., Results: Significant differences were found in both phases of shade determination and shade duplication (P<.017). The total number of color errors with the optimized shade guide was 3.5, which was significantly less than that of Vitapan, 5.1 (P<.001)., Conclusions: The optimized shade guide system improved performance not only in the color selection phase but also in the color of the fabricated crowns., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: In spite of its importance in prosthesis precision and quality, the 3-dimensional repositioning accuracy of cast mounting systems has not been reported in detail., Purpose: The purpose of this study was to quantify the 3-dimensional repositioning accuracy of 6 selected cast mounting systems. Five magnetic mounting systems were compared with a conventional screw-on system., Material and Methods: Six systems on 3 semiadjustable articulators were evaluated: Denar Mark II with conventional screw-on mounting plates (DENSCR) and magnetic mounting system with converter plates (DENCON); Denar Mark 330 with in-built magnetic mounting system (DENMAG) and disposable mounting plates; and Artex CP with blue (ARTBLU), white (ARTWHI), and black (ARTBLA) magnetic mounting plates. Test casts with 3 high-precision ceramic ball bearings at the mandibular central incisor (Point I) and the right and left second molar (Point R; Point L) positions were mounted on 5 mounting plates (n=5) for all 6 systems. Each cast was repositioned 10 times by 4 operators in random order. Nine linear (Ix, Iy, Iz; Rx, Ry, Rz; Lx, Ly, Lz) and 3 angular (anteroposterior, mediolateral, twisting) displacements were measured with a coordinate measuring machine. The mean standard deviations of the linear and angular displacements defined repositioning accuracy., Results: Anteroposterior linear repositioning accuracy ranged from 23.8 ±3.7 μm (DENCON) to 4.9 ±3.2 μm (DENSCR). Mediolateral linear repositioning accuracy ranged from 46.0 ±8.0 μm (DENCON) to 3.7 ±1.5 μm (ARTBLU), and vertical linear repositioning accuracy ranged from 7.2 ±9.6 μm (DENMAG) to 1.5 ±0.9 μm (ARTBLU). Anteroposterior angular repositioning accuracy ranged from 0.0084 ±0.0080 degrees (DENCON) to 0.0020 ±0.0006 degrees (ARTBLU), and mediolateral angular repositioning accuracy ranged from 0.0120 ±0.0111 degrees (ARTWHI) to 0.0027 ±0.0008 degrees (ARTBLU). Twisting angular repositioning accuracy ranged from 0.0419 ±0.0176 degrees (DENCON) to 0.0042 ±0.0038 degrees (ARTBLA). One-way ANOVA found significant differences (P<.05) among all systems for Iy, Ry, Lx, Ly, and twisting., Conclusions: Generally, vertical linear displacements were less likely to reach the threshold of clinical detectability compared with anteroposterior or mediolateral linear displacements. The overall repositioning accuracy of DENSCR was comparable with 4 magnetic mounting systems (DENMAG, ARTBLU, ARTWHI, ARTBLA). DENCON exhibited the worst repositioning accuracy for Iy, Ry, Lx, Ly, and twisting., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A validated universal method requiring no human input is needed to capture and evaluate preparation geometries in a manner that can be used to see the correlation of different parameters., Purpose: The purpose of this study was to present a method of capturing and evaluating crown preparation geometry., Material and Methods: One manually machined acrylic resin block and 9 randomly selected preparations for ceramic complete crowns prepared by general dentists were selected and prepared. The specimens were scanned (3D scanner; Nobel Biocare), and buccolingual and mesiodistal cross section images were collected. The images were imported into digitizing software (Engauge Digitizer 4.1) to convert the outlines into x and y coordinates. Six points were chosen by using a set of algorithms, and the resulting parameters were calculated., Results: The acrylic resin block was milled with a 12 degree total occlusal convergence (TOC) instrument producing a 12.83 degree TOC. For the other specimens, average TOC values ranged from 18 degrees to 52 degrees. The mean average margin width was 0.70 mm, and the mean average base dimension was 6.23 mm. The surface area/volume ratio, resistance length, and limiting taper were also calculated., Conclusions: The method described provides a basis for accurately evaluating preparation geometry without human input., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: In complete mouth reconstructive dentistry, the occlusal vertical dimension may be increased to provide adequate restorative space or to improve esthetics. The effect of increasing the occlusal vertical dimension on the smile is not well understood., Purpose: The purpose of this study was to evaluate the effect of increasing the occlusal vertical dimension on the dimensions of the smile., Material and Methods: Thirty dental students, 12 men and 18 women between the ages of 21 and 30 years old, participated in this study. Polyvinyl siloxane occlusal registrations 2, 4, 6, and 8 mm in thickness were fabricated from articulated stone casts. Posed smile images at occlusal vertical dimension +0, +2, +4, +6, and +8 mm were made with a digital single lens reflex camera mounted on a tripod. A wall-mounted head-positioning device, modified from a cephalometric unit, was used to stabilize the head position. Interlabial gap height, intercommissural width, incisal edge to upper lip, and incisal edge-to-lower lip measurements were made with computer software. The smile index was obtained by dividing width by height. The display zone area was measured by using computer software tracing. One-way repeated measures ANOVA (α=.05) was used for statistical analysis., Results: With an increase in the occlusal vertical dimension, the interlabial gap height, incisal edge to lower lip distance, and display zone area increased significantly (P<.001), whereas the smile index decreased significantly (P<.001). No significant changes were observed in the intercommissural width and incisal edge to upper lip distance., Conclusions: The interlabial gap height, incisal edge-to-lower lip distance, and display zone area increase with increased occlusal vertical dimension. The smile index decreases with increased occlusal vertical dimension. However, the width of the smile and the length of the upper lip tend to remain unchanged., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A patient's smile may not elicit the maximum amount of maxillary gingiva., Purpose: The purpose of this study was to measure the amount of gingival display with 4 different facial expressions., Material and Methods: Video images of 91 randomly selected adults were evaluated to measure the height of gingival display at the maxillary anterior teeth and first premolars when participants were asked to give their biggest smile (requested smile), make a Duchenne smile, mimic an intense grimace of disgust (grimace), and produce a funnel-shaped expression (funnel). Measurements were compared with the Friedman Test with post hoc comparisons (α=.05 for all tests)., Results: The intraclass correlation coefficient was (95% CI)=0.913(0.623, 0.984). At the central and lateral incisors, the grimace and funnel expressions produced the greatest amounts of gingival display. At the canines and the first premolars, both smiles (requested and Duchenne) exhibited the largest amount of gingival display of the 4 facial expressions., Conclusions: Neither smile type revealed a significantly greater amount of gingival display above the maxillary central or lateral incisors but the grimace and funnel facial expressions did (P ≤.001). Above the maxillary canines, both smiles displayed a significantly greater amount of gingiva than did the funnel expression (P<.001), but only the Duchenne smile displayed a greater amount than did the grimace expression (P=.05). Superiorly to the maxillary first premolars, both smile types revealed significantly greater amounts of soft tissue when compared with the other 2 facial expressions (P<.001)., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The replication of natural teeth, especially with single-tooth restorations, represents a challenge. Similar to metal ceramic crowns, different designs of zirconia substructures have been suggested to improve the esthetic results of zirconia ceramic crowns., Purpose of Study: The purpose of the study was to analyze the color of the cervical portion of single zirconia ceramic crowns fabricated with different zirconia coping designs., Material and Methods: The color, measured on the CIELAB color scale, of 3 different groups of restorations (n=10) fabricated with zirconia coping (Lava) and feldspathic porcelain (Noritake Super Porcelain) was analyzed with a spectrophotometer. Conventional zirconia crowns with zirconia facial margins were compared with ceramic crowns with porcelain facial margins and either a horizontal reduction of the zirconia coping (1.0 mm reduction) or an additional vertical reduction (1.0 mm additional reduction). The 3 groups, each with a different coping extension, were examined with a 1-way ANOVA and the Fisher exact test, and the differences of the groups were evaluated by applying ΔE thresholds (α=.05)., Results: The mean color difference among all the groups was not clinically significant (ΔE<3.7). Reduced color differences were present between the 2 porcelain butt margin groups of crowns (ΔE=1.06, between group H and V). Increased differences were present between the zirconia margin group and the porcelain butt margin group (ΔE=2.54 between group C and H; ΔE=2.41 between group C and V). Lab* values were examined in all the groups of crowns to determine the clinical implications., Conclusions: Within the limitation of the study, no significant differences were present among the tested groups of crowns. Nevertheless, although some differences were present between the zirconia margin group and the porcelain butt margin group, reduced differences were present between the 2 different cutback designs., (Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Determining the arbitrary transverse horizontal axis by using anatomic landmarks is a simpler clinical procedure than locating the kinematic transverse horizontal axis; however, accuracy may vary depending on individual patient anatomy., Purpose: The purpose of this study was to investigate an arbitrary transverse horizontal axis relative to the maxillary incisal edge and to examine the magnitude of occlusal error produced when this arbitrary transverse horizontal axis is used to mount casts in an articulator., Material and Methods: Seventy-three adults (43 men, 30 women) participated in this study. The distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge was measured for each participant. A parametric linear regression was used to analyze the effect of sex on the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge by using statistical software (SPSS v19.0; SPSS Inc). A linear correlation analysis was used to compare the distance from the arbitrary transverse horizontal axis to the maxillary central incisal edge with the participant's height (α=.05). Four distances from the arbitrary transverse horizontal axis to the maxillary central incisal edge (80, 90, 110, 120 mm) and 3 interocclusal record thicknesses (1, 2, 3 mm) were mathematically calculated to examine the magnitude of occlusal error at the central incisor contact., Results: The mean distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was 100.12 (SD 5.33) mm for all participants. Overall, 89.04% of the participants fell within 5 mm of the 100-mm distance. No significant differences in the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge position were identified between men and women or with the participant's height. The magnitude of occlusal error at the central incisor contact ranged from 0.45 to 11.26 μm., Conclusions: The distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was not influenced by the sex or height of the participants investigated. Variations in the distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge resulted in minor occlusal discrepancies at the central incisor contact., (Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: In the last 2 decades, several studies have questioned the application of the rule of golden proportion in dentistry., Purpose: The purpose of this study was to test the rule of golden proportion for the maxillary anterior region in a population of young, healthy people with excellent oral hygiene at the Faculty of Dentistry of the University of Szeged., Material and Methods: One hundred and nine participants (36 male, 73 female) were examined, 41 of whom had previously worn orthodontic appliances. A Canon 450D camera, Canon 100 mm Macro lens, and a Sigma 140 DG ring flash were used for digital documentation. The accreditation photography protocol of the American Academy of Cosmetic Dentistry was applied to standardize the images. The width of the teeth from the frontal view was measured digitally. Tooth dimension data were collected and the Mann-Whitney U test was performed (α=.05)., Results: The relative width of the central incisors, lateral incisors, and canines was 1.6:1:0.85 on both sides. The ratios were not influenced by either sex or previous orthodontic treatment., Conclusions: The results demonstrated that, because of the difference in canines in this population, the golden proportion in its original form was not valid for the maxillary anterior region. Orthodontic treatment does not change the dentition toward the golden proportion. The results suggest that the rule of golden proportion should not be used for treatment planning without observing individual modifying factors., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: The anteroposterior orientation of the maxillary occlusal plane has an important role in the creation, assessment, and perception of an esthetic smile. However, the effect of the angle at which this plane is visualized (the viewing angle) in a broad smile has not been quantified., Purpose: The purpose of this study was to assess the esthetic preferences of dental professionals and nondentists by using 3 viewing angles of the anteroposterior orientation of the maxillary occlusal plane., Material and Methods: After Institutional Review Board approval, standardized digital photographic images of the smiles of 100 participants were recorded by simultaneously triggering 3 cameras set at different viewing angles. The top camera was positioned 10 degrees above the occlusal plane (camera #1, Top view); the center camera was positioned at the level of the occlusal plane (camera #2, Center view); and the bottom camera was located 10 degrees below the occlusal plane (camera #3, Bottom view). Forty-two dental professionals and 31 nondentists (persons from the general population) independently evaluated digital images of each participant's smile captured from the Top view, Center view, and Bottom view. The 73 evaluators were asked individually through a questionnaire to rank the 3 photographic images of each patient as 'most pleasing,' 'somewhat pleasing,' or 'least pleasing,' with most pleasing being the most esthetic view and the preferred orientation of the occlusal plane. The resulting esthetic preferences were statistically analyzed by using the Friedman test. In addition, the participants were asked to rank their own images from the 3 viewing angles as 'most pleasing,' 'somewhat pleasing,' and 'least pleasing.', Results: The 73 evaluators found statistically significant differences in the esthetic preferences between the Top and Bottom views and between the Center and Bottom views (P<.001). No significant differences were found between the Top and Center views. The Top position was marginally preferred over the Center, and both were significantly preferred over the Bottom position. When the participants evaluated their own smiles, a significantly greater number (P< .001) preferred the Top view over the Center or the Bottom views. No significant differences were found in preferences based on the demographics of the evaluators when comparing age, education, gender, profession, and race., Conclusions: The esthetic preference for the maxillary occlusal plane was influenced by the viewing angle with the higher (Top) and center views preferred by both dental and nondental evaluators. The participants themselves preferred the higher view of their smile significantly more often than the center or lower angle views (P<.001)., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: There is limited information on the visual and instrumental evaluation of color match between a natural tooth and a ceramic crown., Purpose: The purpose of this study was to evaluate the influence of 2 shade guides on color match, and to evaluate the relationship between color difference (ΔE) values and examiners' assessments of the color match in ceramic crowns., Material and Methods: Thirty-three subjects were selected for a ceramic crown restoration of the maxillary central incisor. Two crowns were fabricated with selected shades from Vitapan Classical and Vita Toothguide 3D-Master shade guides for each subject. The color values of maxillary central incisors, selected shade tabs, and corresponding crowns were measured with a spectrophotometer. The ΔE values between the natural teeth and the crowns and between the selected shade tabs and the corresponding crowns were calculated for each subject and compared with the Student's t test (α=.05). In addition, 3 examiners visually evaluated the clinical acceptability of each crown on a scale from 1 to 6. The agreement among the examiners was assessed with the Kappa test. The scores of examiners for both shade guides were analyzed with the Wilcoxon signed rank test (α=.05)., Results: The results revealed that the color difference values between the teeth and the crowns fabricated with the selected shades from the Vita Toothguide 3D-Master shade guide were significantly smaller than those of the Vitapan Classical guide (P=.003). Similarly, the color difference values between the selected shade tabs from the Vita Toothguide 3D-Master guide and the corresponding crowns were significantly smaller than those of the Vitapan Classical guide (P=.001). However, the ΔE values obtained for both shade guides were within the clinically acceptable range (ΔE<3.7). The kappa values implied moderate agreement among the 3 examiners. The median value of the examiners' scores was 2, which denoted an acceptable color match. In addition, the recorded scores of the 3 examiners showed that there was no significant difference in terms of the color match between the crowns fabricated with either of the 2 shade guides., Conclusions: The ceramic crowns fabricated with the Vita Toothguide 3D-Master shade guide resulted in a closer color match to the natural teeth than those of the Vitapan Classical guide. However, the ΔE values and the examiners' scores were within the clinically acceptable range for both shade guides., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: To select the width of denture teeth, the distance between the marks indicating the location of the canines is usually measured around the curvature of the wax occlusal rim; however, most manufacturers' mold charts provide the measurements of the artificial 6 anterior teeth as if they were on a straight line., Purpose: The purpose of this study was to investigate whether the curve distance between the distal surfaces of the maxillary canines can be related to the combined width (straight measurement) of the 6 anterior teeth in 4 ethnic groups., Material and Methods: Maxillary stone casts were obtained for 160 dentate subjects of 4 ethnic groups (40 whites, 40 blacks, 40 multiracial - descendants of white and black parents, and 40 Asians). The width of each maxillary anterior tooth was measured on the casts with sliding calipers. The combined width of the 6 anterior teeth (CW) corresponded to the sum of the width of each anterior tooth. The curve distance between the distal surfaces of the canines (CD) was measured by using dental tape and sliding calipers. The Pearson correlation coefficient and regression analysis were used to evaluate the relationship between CD and CW in each ethnic group (α=.05)., Results: The mean CD and CW values (in mm) obtained were: whites (CD=52.12; CW=45.65); blacks (CD=56.10; CW=48.13); multiracial (CD=53.58; CW=46.54); and Asians (CD=53.29; CW=46.60). Significant (P<.001) correlations between CD and CW measurements were observed for all ethnic groups studied (whites, r=0.957; blacks, r=0.803; multiracial, r=0.917; and Asians, r=0.881). The following linear regression equations were obtained: whites [CD=1.1(CW)+0.3]; blacks [CD=0.95(CW)+9.3]; multiracial [CD=1.2(CW)-1.1]; and Asians [CD=1.0(CW)+5]., Conclusions: The curve distance between the distal surfaces of the maxillary canines can be accurately related to the combined width of the 6 anterior teeth in the selection of denture teeth for the studied ethnic groups., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: The visual determination of tooth color with standard shade guides is a subjective method of color communication, depending on variables such as the light source, the operator, and the tooth. The assessment of tooth color may be improved by the use of special devices such as colorimeters or spectrophotometers. However, the repeatability and the interdevice agreement of these devices have not been thoroughly investigated., Purpose: The purpose of this study was to evaluate the effect of different illuminants (natural daylight, dental unit lamp, and daylight lamp) on the matching repeatability of 2 intraoral spectrophotometers (Easyshade and SpectroShade)., Material and Methods: The maxillary right central incisor and canine and the mandibular left central incisor of each of 10 dental students were measured by a single operator using both devices. The color of each tooth was assessed 3 times with each device under each of the 3 different illuminants (natural daylight, a dental unit lamp, and a daylight lamp). The device readings were expressed in Vitapan 3D-Master shade codes. Statistical analysis was performed and the level of agreement was assessed with the Spearman Correlation Coefficient., Results: A particularly high to moderate level of agreement among the readings made under natural daylight, a dental unit lamp, and a daylight lamp was observed for both devices (P<.01), suggesting that their matching repeatability was not completely satisfactory for clinical practice. A moderate and a moderate to high level of agreement was found among Easyshade readings when the 3 different illuminants were used. The level of agreement for the respective SpectroShade readings was particularly high to high (P<.001). A particularly low level of agreement was found among the respective Easyshade and SpectroShade readings performed under any of the illuminants tested (P<.05), suggesting poor interdevice reliability., Conclusions: The matching repeatability of both devices under natural daylight, a dental unit lamp, and a daylight lamp was not completely satisfactory for clinical practice. The effects of different illuminants seem to be more pronounced for Spectroshade than for Easyshade. The interdevice agreement between the 2 devices tested was poor, suggesting that the 2 devices were not compatible., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Various aspects of anatomic tooth dimensions have been examined in a number of studies where data are primarily based on the measurements obtained from white subjects. Additional factors such as ethnicity should be considered to produce a more comprehensive analysis., Purpose: The purpose of this study is to compare the anatomic crown dimensions of extracted maxillary teeth in Asian and white populations., Material and Methods: The width/length ratio (%) was calculated with standardized digital images of extracted maxillary anterior teeth from 157 Asian and 142 white subjects. Statistical analysis was performed to compare the 4 tooth groups (central incisiors, lateral incisiors, canines, and premolars) of the 2 ethnicities. The distribution of the outcome variables were examined for normality with the Kolmigorov-Smirnov test. Independent sample t tests were used to examine differences in outcomes in Asian and white subjects., Results: There was a significant difference (P<.05) in the width/length ratios of all maxillary anterior teeth in Asian and white subjects. In addition, there was a significant difference in the width of unworn central incisors and the length of worn lateral incisors and canines., Conclusions: Ethnicity influences width/length ratios for all 4 anterior maxillary teeth. Anterior maxillary teeth in Asian subjects appear to be more slender when compared with those in white subjects., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Most faces are not symmetrical, and this complicates the task of aligning the anterior segment of the teeth for the restorative dentist, orthodontist, or oral and maxillofacial surgeon. The dental literature provides conflicting advice regarding guidelines for aligning the anterior teeth., Purpose: The purpose of this study was to determine the sensitivity of laypersons to variations in the alignment of the anterior segment within a symmetrical face, and to investigate which guidelines were preferred by laypersons and prosthodontists when aligning this segment., Material and Methods: Lay participants (21) were shown a series of 25 modified images of faces on a computer screen and asked to indicate 'noticeability' of tilt and, with another series of 19 images, preference for angulation of the anterior segment. Prosthodontists (14) were shown a further set of 7 images and asked to use a Clinometer to select an appropriate angle. Statistical comparisons were performed with multinomial goodness-of-fit tests and repeated measures ANOVA, followed by Sidak multiple comparisons tests (α=.05)., Results: The average angle at which the tilt of the anterior segment within a symmetrical face became noticeable to the laypersons was approximately 1 degree. No significant correlation (P=.15) was found between the laypersons' choice of angle for the anterior segment and the angle of the eyes, lips, or horizon, but an angle of 0 degrees was chosen significantly more often than the other angles offered (P<.001). The prosthodontists generally chose an angle close to zero., Conclusions: The results suggest that the threshold tilt within a symmetrical face, for noticeability by laypersons, is about 1 degree, and that for both laypersons and prosthodontists, the most important guideline is not any individual facial feature or the horizon but the face as a whole., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Female teeth are considered more rounded and male teeth more quadrangular. Although lacking in scientific support, this theory helps in selecting the mold of artificial teeth for dentures. Parameters that are more reliable are sought to determine gender differences in tooth form., Purpose: The purpose of this study was to assess possible differences between genders in terms of tooth form: oval, triangular, or quadrangular., Material and Methods: The sample comprised 433 subjects with a mean age of 15 years selected from a population of Brazilian high school students. The maxillary right central incisor (MCI) of each subject was photographed. The images were adjusted to standardize the long axis of the tooth in the vertical position. The AutoCAD computer program was used to analyze graphically the geometric form of the tooth. According to analysis results, form was classified as oval, triangular, or quadrangular. Intraexaminer consistency was analyzed by using linear correlation coefficient and Bland Altman analysis. The relationship between gender and tooth form was analyzed by chi-square and linear regression (α=.05)., Results: In women, the form was 57.73% (n=127) oval, 23.54% (n=52) triangular, and 18.64% (n=41) quadrangular; while in men, the form was 54.93% (n=117) oval, 36.15% (n=77) triangular, and 8.92% (n=19) quadrangular (P<.001)., Conclusions: The oval form was the most prevalent in both genders. However, the triangular form was more common in men than in women, and the quadrangular form more frequent in women than in men., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: When making complete dentures, clinicians may have difficulty with selection of properly sized denture teeth., Purpose: The purpose of this study was to determine if there are specific measurements made on an edentulous cast that could be useful to clinicians for selection of proper maxillary anterior denture tooth width., Material and Methods: Following Institutional Review Board approval, measurements were made on 50 maxillary and mandibular sets of complete denture casts and their marked and contoured occlusion rims and record bases consecutively submitted to a dental laboratory. The following 6 measurements were recorded for each set of casts: left mid-maxillary to right mid-maxillary, representing the distance between the respective residual ridge crest points adjacent to each canine eminence; left retromolar pad to right retromolar pad; incisive papilla to left hamular notch; incisive papilla to right hamular notch; left hamular notch to right hamular notch; and incisive papilla to vibrating line. These measurements were statistically compared with the control, the canine-to-canine distance as marked on the contoured maxillary occlusion rim to indicate the relaxed commissures. The casts were also classified as small, medium or large based upon the tooth width specified by the commercial mold guide for their respective canine-to-canine control measurement. The estimation bias was determined for each of the 6 measurements, and for those measurements for which the bias was significantly different from zero, a bias-correction was applied. St. Laurent's coefficient was used to describe the agreement between each (bias-corrected) measurement and the canine-to-canine control. A commercial guide was used to determine the accuracy of each of the 6 bias-corrected measurements in classifying denture teeth width as small, medium or large as compared to the same classification using the canine-to-canine control., Results: The bias-corrected measurement from the left hamular notch mark to the right hamular notch mark, obtained by adding 10 mm, exhibited the greatest degree of agreement with the control. This measurement was also the only one of the 6 that correctly classified more than 50% of both the medium and large casts. None of the 6 measurements classified more than 30% of the small casts correctly., Conclusions: Of the 6 measurements considered here, the bias-corrected measurement from left hamular notch mark to right hamular notch mark was preferred for selecting denture teeth width., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: In rehabilitating edentulous patients, selecting appropriately sized teeth in the absence of preextraction records is problematic., Purpose: The purpose of this study was to investigate the relationships between some facial dimensions and widths of the maxillary anterior teeth to potentially provide a guide for tooth selection., Material and Methods: Sixty full dentate Malaysian adults (18-36 years) representing 2 ethnic groups (Malay and Chinese), with well aligned maxillary anterior teeth and minimal attrition, participated in this study. Standardized digital images of the face, viewed frontally, were recorded. Using image analyzing software, the images were used to determine the interpupillary distance (IPD), inner canthal distance (ICD), and interalar width (IA). Widths of the 6 maxillary anterior teeth were measured directly from casts of the subjects using digital calipers. Regression analyses were conducted to measure the strength of the associations between the variables (alpha=.10)., Results: The means (standard deviations) of IPD, IA, and ICD of the subjects were 62.28 (2.47), 39.36 (3.12), and 34.36 (2.15) mm, respectively. The mesiodistal diameters of the maxillary central incisors, lateral incisors, and canines were 8.54 (0.50), 7.09 (0.48), and 7.94 (0.40) mm, respectively. The width of the central incisors was highly correlated to the IPD (r=0.99), while the widths of the lateral incisors and canines were highly correlated to a combination of IPD and IA (r=0.99 and 0.94, respectively)., Conclusions: Using regression methods, the widths of the anterior teeth within the population tested may be predicted by a combination of the facial dimensions studied., ((c) 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: The loss of one or more of the incisal embrasures may pose a problem in restoring missing tooth structure. Despite its acknowledged importance in dental esthetics, few researchers have investigated the esthetic impact of incisal embrasures., Purpose: The purpose of this study was to compare parameters of the incisal embrasures of natural maxillary anterior teeth (ND) with those of prosthetically restored maxillary anterior teeth (PRD) and to compare the resemblance of the prosthetic restoration to natural form., Material and Methods: Twenty gypsum casts of the maxillary anterior teeth (MAT) of patients made at the completion of their orthodontic treatment comprised the control group. The experimental group consisted of 20 gypsum casts of prosthetically restored maxillary anterior segments. Five incisal embrasures of each cast were digitally photographed under uniform, standardized conditions: the incisal embrasures between the canine and lateral incisor on each side, between the lateral and central incisors on each side, and between the 2 central incisors. The photographs were measured by image analyzing software (Bioquant Nova Prime). The parameters compared were: (1) the areas of the incisal embrasures in the natural and prosthetic casts (measured in mm(2)); (2) the areas of homological incisal embrasures in each of the groups; and (3) the degree of lateral symmetry of the natural casts as compared to the prosthetic casts. The results were subjected to 2-way ANOVA and Student t tests (alpha =.05)., Results: The total area of incisal embrasures of the PRD casts was smaller than the total area of those of the natural dentition casts (P=.005). The incisal embrasures of the PRD casts were smaller than the homological embrasures of the natural dentition casts (P<.01). Both groups demonstrated a lack of lateral symmetry (P<.001). The natural dentition casts demonstrated a greater asymmetry than the restored dentition casts (canine/lateral P<.045 and lateral/central P<.035). There was no significant difference in the sizes of the central incisal embrasures of the 2 groups. The corresponding incisal embrasure areas (ND versus PRD) were significantly different, except for the 2 central embrasures., Conclusions: Prosthetically restored dentition casts differed from natural dentition casts in 2 parameters: the area of the incisal embrasures and the degree of lateral symmetry.

Statement of Problem: There is no scientific information regarding the selection of the color of teeth for edentulous patients., Purpose: The purpose of this study was to evaluate linear regression models that may be used to predict color parameters for central incisors of edentulous patients based on some characteristics of dentate subjects., Material and Methods: A spectroradiometer and an external light source were set in a noncontacting 45/0 degree (45-degree illumination and 0-degree observer) optical configuration to measure the color of subjects' vital craniofacial structures (maxillary central incisor, attached gingiva, and facial skin). The subjects (n=120) were stratified into 5 age groups with 4 racial groups and balanced for gender. Linear first-order regression was used to determine the significant factors (alpha=.05) in the prediction model for each color direction of the color of the maxillary central incisor. Age, gender, and color of the other craniofacial structures were studied as potential predictors. Final predictions in each color direction were based only on the statistically significant factors, and then the color differences between observed and predicted CIELAB values for the central incisors were calculated and summarized., Results: The statistically significant predictors of age and gender accounted for 36% of the total variability in L*. The statistically significant predictor of age accounted for 16% of the total variability in a*. The statistically significant predictors of age and gender accounted for 21% of the variability in b*. The mean Delta (SD) between predicted and observed CIELAB values for the central incisor was 5.8 (3.2)., Conclusions: Age and gender were found to be statistically significant determinants in predicting the natural color of central incisors. Although the precision of these predictions was less than the median color difference found for all pairs of teeth studied, and may be considered an acceptable precision, further study is needed to reduce this precision to the limit of detection.

Statement of Problem: In addition to color, translucency is one of the primary factors influencing the esthetics of a dental prosthesis. Due to difficulties in measuring the translucency of natural teeth, minimal data are available., Purpose: The purpose of this study was to measure the translucency of newly extracted maxillary central incisors and analyze the relationship between translucency, anatomic location, and age., Material and Methods: The translucency of 32 newly extracted maxillary central incisors was measured with a spectrocolorimeter (PR-650) at 9 locations on the tooth crown. These locations were identified by dividing the tooth incisally to cervically and medially to laterally in equal dimensions. The relationships between transmittance, locations, and age were analyzed by univariate analysis of variance (alpha=.05)., Results: The transmittance of maxillary central incisors ranged from 0.13% to 0.65%, which decreased from incisal to cervical (P<.05). Age also affected transmittance in certain locations of the crown; older teeth demonstrated higher transmittance (P<.05)., Conclusions: Transmittance of the maxillary central incisor was variable at different locations of the crown and was positively correlated with age.

Statement of Problem: Matching a natural maxillary central incisor to a metal ceramic crown is one of the most difficult challenges in clinical dentistry due to the limitations of dental shade guides and the subjectivity of perceptual evaluation., Purpose: The purpose of this study was to assess the clinical effectiveness of a spectrophotometric shade-matching system on tooth color reproduction., Material and Methods: Two metal ceramic crowns were fabricated for a maxillary central incisor for 36 patients using 2 shade-matching techniques. The first technique was conventional visual matching using 3 shade guide systems, and the second was an instrument-based color-matching technique using a new spectrophotometric system. Color difference (DeltaE) values between the contralateral natural tooth and each of the 2 crowns were calculated in the cervical, middle, and incisal regions. The DeltaE values were compared using a Student's t test (alpha=.05). Three calibrated examiners evaluated the color match by ranking it from 1 to 10 (10 = perfect match; 1 = no match; < or =8, accepted; > or =7, rejected). McNemar's test was used to calculate the odds ratio of accepting restorations fabricated using a spectrophotometric system to conventional methods., Results: Results revealed that the mean DeltaE values of crowns matched with the spectrophotometer were significantly lower than those using a conventional technique (P<.001). The odds ratio of 12.5 was calculated, indicating that conventionally matched crowns were more likely to be rejected than those matched using the spectrophotometer (P<.001)., Conclusions: In this clinical study, crowns fabricated using a dedicated spectrophotometer had a significantly better color match and a lower rate of rejection due to shade mismatch compared to crowns fabricated with a conventional shade-matching method.

Statement of Problem: It remains unclear which shade guide system is most representative of the shades found in the human dentition., Purpose: The purpose of this study was to determine and to compare the coverage errors (CEs) of 3 different shades in a selected population., Material and Methods: The coverage errors of the following shade guide systems were evaluated to determine which shade guide system is most effective in producing the best visual shade match: (1) Vita Lumin, (2) Chromascop, (3) Vitapan 3D Master, and (4) a combination of the 3 shade guide systems. The spectral reflectance values of the central one ninth (1-mm diameter) of each shade tab (without a backing) were measured with a spectroradiometer and an external light source at wavelengths from 380 nm to 780 nm at 2-nm intervals. All spectral reflectance measurements were made using 0-degree observer and 45-degree illumination and then converted to CIE values. The color values of 359 anterior teeth were measured with the same protocol. The CEs for each of the 359 anterior teeth for each shade guide system, and with all 3 shade guide systems, were determined and averaged. Repeated measure ANOVA was used to evaluate the mean minimum CEs within-subject (shade guide system) and between-subject (age) difference as well as the interaction between these variables (alpha=.05). Then, a post hoc multiple comparison was performed using the Tukey-Kramer test., Results: A significant difference (P<.001) was found among the mean minimum CEs of the 3 shade guide systems and their combination, but not between age groups (P=.384). An interaction was found between shade guide systems and age (P<.001). The Tukey-Kramer test revealed that the mean minimum CEs for Vita Lumin (5.39 DeltaE) and Chromoscop (5.28 DeltaE) shade guide systems were not significantly different from each other. However, the combination of all 3 shade guide systems (3.69 DeltaE) and Vitapan 3D Master (3.93 DeltaE) were significantly different from the Vita Lumin and Chromoscop shade guide system. The rankings of the shade guide systems within each age group were similar between the age groups., Conclusions: The Vitapan 3D Master shade guide system resulted in the lowest coverage errors compared to the Vita Lumin or Chromascop shade guide systems. Coverage errors for the Vitapan 3D Master shade guide system did not differ significantly from the coverage errors when all 3 shade guide systems were combined.

Statement of Problem: The size and form of the maxillary anterior teeth are important in achieving pleasing dental and facial esthetics. However, little scientific data have been defined as criteria for evaluating these morphological features., Purpose: This study analyzed the clinical crown dimensions of maxillary anterior teeth to determine whether consistent relationships exist between tooth width and several facial measurements in a subset of the Turkish population., Material and Methods: Full-face and anterior tooth images of 100 Turkish dental students viewed from the front and engaged in maximum smiling were recorded with digital photography under standardized conditions. Gypsum casts of the maxillary arches of the subjects were also made. The dimensions of the anterior teeth, the occurrence of the golden ratio, the difference between the actual and perceived sizes, and the relationship between the anterior teeth and several facial measurements by gender were analyzed using the information obtained from both the computer images and the casts. One-sample, 2-sample, and paired t tests, and repeated-measures analysis of variance and Duncan multiple-range tests were performed to analyze the data (alpha=.05)., Results: The dimensions of the central incisors (P<.05) and canines (P<.01) varied by gender. The existence of the so-called "golden proportion" for the maxillary anterior teeth as a whole was not found. Significant differences emerged when the mean ratios between various perceived widths were compared with their ideal golden ratios (P<.01). Proportional relationships between the bizygomatic width and the width of the central incisor, and the intercanine distance and the interalar width in women were observed., Conclusion: The maxillary central incisor and canine dimensions of men were greater than those of women in the Turkish population studied, with the canines showing the greatest gender variation. Neither a golden proportion nor any other recurrent proportion for all anterior teeth was determined. Bizygomatic width and interalar width may serve as references for establishing the ideal width of the maxillary anterior teeth, particularly in women.

Statement of Problem: The condylar position can vary depending on several factors. One factor is the influence of occluding teeth. If the influence from occluding teeth could be eliminated, it might be possible to evaluate the condylar position obtained from masticatory muscle contraction., Purpose: The purpose of this pilot study was to determine the placement of the condyles by contracted masticatory muscles without influence from occluding teeth., Material and Methods: For a group of 11 participants, 3 dentists were assigned, in turn, to fabricate a centric relation interocclusal record using bimanual manipulation on each member of the group. After obtaining the centric relation interocclusal records using bimanual manipulation, the records were stored in room temperature water. Subsequently, each of the 11 patients had an anterior deprogrammer fabricated and were given instructions to wear the anterior deprogrammer for 60 minutes. The anterior deprogrammer was designed with the contacting surface perpendicular to the arc of close of the mandibular incisors. In addition, the anterior deprogrammer was relined to eliminate any movement under force, and the occluding surface of the deprogrammer was free of any indentations. After wearing the deprogrammer, 4 interocclusal records (3 in a reclined position and 1 in an upright position to ensure the condylar position did not change in the upright position) were made by having the patient squeeze and close into a properly adapted, trimmed, and warmed interocclusal record. The condylar position in centric relation recorded in interocclusal records using bimanual manipulation was compared to the condylar position recorded by the contraction of the masticatory muscles against an anterior deprogrammer using a condylar position indicating device. The data were analyzed with a 2-independent-samples test of proportions, alpha=.05 (1-tail)., Results: The condylar positions obtained using bimanual manipulation repeated the condylar position within the 0.11-mm tolerance of the Centri-Check instrument in 33 out of 33 opportunities (100%). The condylar positions obtained by using the anterior deprogrammer technique repeated the condylar position within the 0.11-mm tolerance of the Centri-Check in 43/44 opportunities (97.7%). The sample size used in this pilot study was not large enough to detect a very small actual difference (5 percentage points or less) between the 2 methods, should such a difference exist., Conclusion: The results of this pilot study indicate that, without influence from occluding teeth, the contraction of the masticatory muscles places the condyles into the same position as centric relation.

Statement of Problem: Dimensions of teeth have been available for a century. Some significant and clinically relevant aspects of dental esthetics, however, such as the crown width/length ratios, have not been presented in tooth morphology sources until recently., Purpose: The purpose of this study was to analyze the anatomic crowns of 4 tooth groups (central incisors, lateral incisors, canines, and first premolars) of the maxillary dentition with respect to width, length and width/length ratios and determine how these parameters are influenced by the incisal edge wear., Material and Methods: Standardized digital images of 146 extracted human maxillary anterior teeth from white subjects (44 central incisors, 41 lateral incisors, 38 canines, 23 first premolars) were used to measure the widest mesiodistal portion "W" (in millimeters) and the longest inciso-cervical/occluso-cervical distance "L" (in millimeters). The width/length ratio "R" (%) was calculated for each tooth. A 1-way analysis of variance was used to compare the mean values of W, L, and R for the different groups ("unworn" and "worn" subgroups, except for premolars). Multiple least significant difference range tests (confidence level 95%) were then applied to determine which means differed statistically from others., Results: There was no influence of the incisal wear on the average value of W (width) within the same tooth group. The widest crowns were those of central incisors (9.10 to 9.24 mm) > canines (7.90 to 8.06 mm) > lateral incisors (7.07 to 7.38 mm). Premolars (7.84 mm) had similar width as canines and worn lateral incisors. The L-value was logically influenced by incisal wear (worn teeth were shorter than unworn teeth) except for lateral incisors. The longest crowns were those of unworn central incisors (11.69 mm) > unworn canines (10.83 mm) and worn central incisors (10.67 mm) > worn canines (9.90), worn and unworn lateral incisors (9.34 to 9.55 mm), and premolars (9.33 mm). Width/length ratios also showed significant differences. The highest values were found for worn central incisors (87%) and premolars (84%). The latter were also similar to worn canines (81%), which constituted a homogeneous group with worn lateral incisors (79%) and unworn central incisors (78%). The lowest ratios were found for unworn canines and unworn lateral incisors (both showing 73%)., Conclusions: Along with other specific and objective parameters related to dental esthetics, average values for W (mesiodistal crown dimension), L (inciso-cervical crown dimension), and R (width/length ratio) given in this study for white subjects may serve as guidelines for treatment planning in restorative dentistry and periodontal surgery.

Statement of Problem: It has been recommended that the anterior tooth midline be placed coincidently with the midline of the face (facial midline). The location of the facial midline depends largely on the judgment of the clinician. The amount of deviation between these 2 midlines that is noticeable to the observer has not been fully investigated., Purpose: The observable deviation between the anterior tooth and facial midlines in a limited sample of dentate subjects was recorded., Material and Methods: Full facial-view, standardized photographs (x1/1.5) of 45 subjects, meeting very limited inclusion/exclusion criteria and undergoing routine dental treatment at Tel Aviv Dental School, were examined by 10 observers: 5 dentists and 5 nondental personnel who were given only a brief explanation of facial and tooth midlines. The examiners asked whether the facial and anterior tooth midlines deviated. The photographs then were scanned onto a computer screen, and the facial midline was determined by bisecting the distance between the medial angles of the eyes. The distance between a line perpendicular to this point and the contact point of the central incisors was measured by one calibrated examiner. The photographs were grouped according to the midline deviation: group 1, <1 mm; group 2, 1 to 2 mm; and group 3, >2 mm. Two photographs with oblique anterior tooth midlines were removed from the study because they were so easily detected. The observers' detection rates for the remaining midline deviation were compared and subjected to 1-way analysis of variance to identify significant differences at the 95% level of confidence. A post hoc Student t test was performed to identify significant differences among the groups., Results: Dentists and nondental personnel demonstrated a similar ability to notice deviations of anterior tooth and facial midlines. Midline deviations of <1 mm (group 1) were detected by 6 of 10 observers in 4 of 29 photographs (14%). Midline deviations of 1 to 2 mm (group 2) were detected by 6 observers in 3 of 8 photographs (37%). Midline deviations of >2 mm (group 3) were detected by 6 observers in 5 of 6 photographs (83%). The greater the deviation, the higher the detection rate. Significant differences were found between group 3 and the other 2 groups (P<.01)., Conclusion: Within the limitations of this study, the greater the deviation of anterior tooth and facial midlines, the higher the detection rate. Nearly half of the 10 observers involved in this investigation were unable to detect midline deviations of <2 mm.

Statement of Problem: Inadequate preparation of teeth for metal ceramic crowns can significantly influence the ultimate form and longevity of the definitive restoration, as well as adversely affect the supporting tissues., Purpose: The purpose of the study was to determine the effect that 3 different tooth preparation techniques had on an operator's ability to appropriately and consistently prepare teeth for metal ceramic crowns., Material and Methods: Thirty typodont maxillary central incisor teeth were mounted individually and randomly allocated to 3 equal groups (A, B, and C). One operator was asked to prepare each tooth for a metal ceramic crown. A freehand approach was used to prepare the teeth in Group A, which acted as a control. Groups B and C were prepared with the assistance of a silicone index and a suitable depth gauge bur, respectively. A silicone index of the unprepared tooth, into which contrasting silicone was injected to occupy the space created by tooth preparation, was sectioned in the midline. Images of the sectioned index were captured with an optical microscope (resolution +/- 0.02 mm), which was attached to a personal computer. A calibrated image analysis program was used to measure the depth of preparation (in millimeters) at 5 points (labial cervical, mid-labial, incisal, mid-palatal, and palatal cervical) on 2 occasions. These results were pooled and averaged to give a mean labial and palatal preparation depth (in millimeters) and incisal edge reduction. The data were analyzed by use of a 1-way analysis of variance and Scheffe's post hoc statistical test (P<.05)., Results: The mean depths of labial and palatal preparation for Groups A, B, and C were 1.28 and 0.47 mm; 1.46 and 0.56 mm; and 1.45 and 0.63 mm, respectively. The difference between the groups' labial preparation depth was not significant (P=.06), but the difference for palatal preparation depth was significant (P=.01). The mean incisal reduction was 3.00 mm for Group A, 2.74 mm for Group B, and 2.13 mm for Group C (P=.00)., Conclusion: Within the limitations of this study, it was concluded that preparation of teeth for metal ceramic crowns without the use of devices to help gauge reduction depth can result in insufficient labial reduction and incisal overreduction.

Statement of Problem: In prosthodontics, sex-related differences in tooth forms are assumed, and optimal esthetics is further assumed to be achieved only if the face, arch, and tooth forms are in harmony. However, there is no universally accepted rule or mathematical method to define these morphologic features., Purpose: The purpose of this study was to evaluate whether anterior tooth from reflected gender and to question the hypothesis that there was a correlation among face, arch, and tooth forms on the basis of dentists' perceptions., Materials and Methods: Photographic records including full face, dental arch, and anterior tooth images of 60 dental students were made by use of digital photography. A database was arranged as a questionnaire for evaluation by prosthodontists who were asked to define the sex and morphologic features of the subjects by examining stored images of the subjects. Thirteen prosthodontists, all with at least 10 years of experience, served as experts and performed these evaluations twice at 2-week intervals. Kappa statistic was used to measure intraobserver and interobserver agreement., Results: The average correctly identified values in females and males were 53% and 58%, respectively. However, the proportions of females and males who were identified correctly and completely the same in both the first and second evaluations were 36% for females and 41% for males. According to the observations of the experts, face-to-arch form (54%) and face-to-tooth form (51%) correlations were higher than the tooth-to-arch form correlation. The overall correlation among face, arch, and tooth forms was 31%. The experts were in fair agreement in defining tooth forms., Conclusions: The results of gender identification of the subjects showed that the experts were unsuccessful in distinguishing the actual sex by the visual assessment of anterior tooth segment alone, with a fair agreement between 2 evaluation sessions. There were also significant interobserver and intraobserver differences in classifying face, arch, and especially tooth forms. Furthermore, the correlation among these forms was not highly defined.