Facial height comparison in young white and black Brazilian subjects with normal occlusion.

INTRODUCTION: In this study, we aimed to cephalometrically compare anterior and posterior facial heights in young white and black Brazilian subjects with normal occlusion and to verify sexual dimorphism. METHODS: The sample comprised the lateral cephalograms of untreated normal Brazilians, divided into 2 groups. Group 1 included 74 white subjects (37 of each sex), with a mean age of 13.71 years (SD 0.84); group 2 included 56 black subjects (28 of each sex), with a mean age of 13.86 years (SD 0.92). The variables studied were obtained from various cephalometric analyses. Sexual dimorphism was investigated in the groups. Independent t tests were used for intergroup comparisons. RESULTS: The white subjects had significantly greater upper anterior facial height (UAFH) and proportion of UAFH to total anterior facial height (TAFH), and significantly smaller proportion of lower anterior facial height (LAFH) to TAFH than the black subjects. Black boys had significantly greater total posterior face height (TPFH) and UAFH and upper posterior face height (UPFH) and UPFH/TPFH proportion than black girls. Black girls had significantly greater LPFH/TPFH proportion than boys. White boys had significantly greater UPFH and UPFH/TPFH proportion than white girls. White girls had significantly greater LPFH/TPFH and facial height index values than boys. CONCLUSIONS: White subjects had larger UAFH, whereas black subjects had proportionally larger LAFH. Boys have a greater tendency for a vertical pattern than girls.

Alignment stability in Class II malocclusion treated with 2- and 4-premolar extraction protocols.

INTRODUCTION: The purpose of this study was to compare the postretention stability of the correction of mandibular anterior-tooth irregularity in patients with Class II malocclusions whose orthodontic treatments included extraction of 2 or 4 premolars. METHODS: A total of 66 patients were selected who initially had at least one-half-cusp Class II malocclusions. Nineteen patients (9 male, 10 female) with an initial mean age of 14.04 years were treated with extraction of 2 premolars (group 1); 47 patients (20 male, 27 female) with an initial mean age of 13.03 years were treated with extraction of 4 premolars (group 2). A subgroup of group 2, with a similar amount of initial anterior-tooth irregularity as group 1, was also compared with group 1. Little's irregularity index was used to evaluate anterior tooth irregularity in dental casts obtained from each patient before treatment, after treatment, and 5 years after active treatment. Initial cephalometric variables, initial treatment priority index, pretreatment age, treatment time, and posttreatment time of the groups were compared with t tests. Similarly, Little's irregularity index values at prettreament, posttreatment, and postretention were also compared with the t test. Cephalometric treatment changes within groups were evaluated with dependent t tests. RESULTS: There were no statistically significant differences in posttretention anterior-tooth irregularity between groups 1 and 2 or the subgroup. CONCLUSIONS: Treatment of Class II malocclusion with extraction of either 2 maxillary premolars or 4 premolars provides the same mandibular anterior-tooth alignment stability.

Comparative evaluation of esthetic perception of black spaces in patients with mandibular incisor extraction.

OBJECTIVE: To evaluate the degree of perception of laypersons, dental professionals, and students with regard to the esthetics of the smile in cases of mandibular incisor extractions with the presence of black spaces between them. MATERIALS AND METHODS: Changes were made to a front-view intraoral photograph of occlusion treated by means of a mandibular incisor extraction, simulating various configurations of black spaces between mandibular incisors. For this purpose, a specific image manipulation program was used (Photoshop CS3). After digital manipulation the photographs were printed on photographic paper and attached to a questionnaire and distributed to laypersons, dental professionals, and students (n  =  90). To evaluate the degree of esthetics, an attractiveness scale was used, in which a score of 0 would represent "hardly attractive," 5 "attractive," and 10 "very attractive." The differences between examiners were checked using the Mann-Whitney test. All of the statistics were performed with a confidence level of 95%. RESULTS: The results demonstrated that dentistry professionals, students, and laypersons were capable of identifying cases with and without black spaces. In all groups evaluated, with the increase in black spaces the scores assigned were statistically lower (P < .05). CONCLUSIONS: It could be concluded that black spaces occurring after mandibular incisor extraction had a negative repercussion on dental esthetics for the dentist, the dental student, and the layperson.

Perception of the esthetic impact of mandibular incisor extraction treatment on laypersons, dental professionals, and dental students.

OBJECTIVE: To evaluate the degree of perception of laypersons, dental professionals, and dental students regarding dental esthetics in cases with mandibular central incisor extraction. MATERIALS AND METHODS: Using a smile photograph of a person with normal occlusion and all teeth, modifications were made to reflect the extraction of a mandibular incisor of various compositions and sizes. For this purpose a program specifically for image manipulation (Adobe Photoshop CS3, Adobe Systems Inc) was used. After manipulation the images were printed on photographic paper, attached to a questionnaire and distributed to laypersons, dental professionals, and dental students (n  =  90) to evaluate the degree of perception and esthetic using a scale of attractiveness, where 0  =  hardly attractive, 5  =  attractive, and 10  =  very attractive. The differences between examiners were checked by the Mann-Whitney test. All the statistics were performed with a confidence level of 95%. RESULTS: The results demonstrated the skill of the dental professionals and dental students in perceiving the difference between cases of normal occlusion and cases where an incisor was lacking (P < .05). The photograph in which the lateral incisors were shown to be larger than the central incisor was the one that obtained the highest value among the cases of extraction in all groups of evaluators. CONCLUSIONS: It can be concluded that dental professionals and dental students are more skillful at identifying deviation from normality. In addition, central incisor extraction should always be discarded when there are other treatment options available.

Effect of 10% papain gel on enamel deproteinization before bonding procedure.

OBJECTIVE: To test the null hypothesis that enamel deproteinization with 10% papain gel does not increase the shear bond strength of orthodontic brackets bonded with resin-modified glass ionomer cement (RMGIC). MATERIALS AND METHODS: One hundred and twenty bovine incisors were used and divided into eight groups: 1) Transbond XT according to the manufacturer's recommendations, 2) Transbond XT deproteinized with 10% papain gel, 3) RMGIC without enamel deproteinization and without etching, 4) RMGIC without enamel etching and with deproteinization with 10% papain gel, 5) RMGIC deproteinized with 10% papain gel and etched with polyacrylic acid, 6) RMGIC deproteinized with 10% papain gel and etched with phosphoric acid, 7) RMGIC deproteinized with 2.5% sodium hypochlorite, and 8) RMGIC etched with polyacrylic acid. After bonding, the mechanical tests were performed in a Universal mechanical test machine. The values obtained were submitted to an analysis of variance and afterward to the Tukey test (P < .05). RESULTS: It was demonstrated that group 2 presented the highest shear bond strength value, and this differed statistically from the others; group 3 presented the lowest value and showed no differences from groups 4, 5, 7, and 8. Regarding the Adhesive Remnant Index, groups 2 and 6 presented the best results and groups 3 and 8 the worst. It could be concluded that enamel deproteinization with 10% papain gel increases the shear bond strength, irrespective of the etching agent. CONCLUSIONS: The hypothesis is rejected. Papain gel was shown to be a new ally in the orthodontic clinic.

A comparison of skeletal, dentoalveolar and soft tissue characteristics in white and black Brazilian subjects.

OBJECTIVE: This study aimed to compare skeletal, dentoalveolar and soft tissue characteristics in white and black Brazilian subjects presenting normal occlusions. MATERIAL AND METHODS: The sample comprised the lateral cephalograms of 106 untreated Brazilian subjects with normal occlusion, divided into two groups: Group 1- 50 white subjects (25 of each gender), at a mean age of 13.17 years (standard deviation 1.07); and Group 2- 56 black subjects (28 of each gender), at a mean age of 13.24 years (standard deviation 0.56). Variables studied were obtained from several cephalometric analyses. Independent t tests were used for intergroup comparison and to determine sexual dimorphism. RESULTS: black subjects presented a more protruded maxilla and mandible, a smaller chin prominence and a greater maxillomandibular discrepancy than white subjects. Blacks presented a more horizontal craniofacial growth pattern than whites. Maxillary and mandibular incisors presented more protruded and proclined in black subjects. The nasolabial angle was larger in whites. Upper and lower lips were more protruded in blacks than in whites. CONCLUSIONS: The present study found a bimaxillary skeletal, dentoalveolar and soft tissue protrusion in black Brazilian subjects compared to white Brazilian subjects, both groups with normal occlusion. Upper and lower lips showed to be more protruded in blacks, but lip thickness was similar in both groups.

Applicability of Bolton tooth-size ratios in racial groups.

AIM: To determine whether there is sexual dimorphism regarding Bolton ratios within four ethnic groups and to compare them against Bolton standards. METHODS: The sample consisted of 140 dental study casts of untreated normal occlusion subjects, derived from four racial groups: black, white, Afro-Mediterranean, and Japanese. Anterior and overall Bolton ratios were calculated for each cast. The Kolmogorov-Smirnov test, t test, and one-way ANOVA were used. RESULTS: No statistically significant sexual dimorphism in anterior or total tooth-size ratios were found within any group. Only the Japanese anterior ratio (75.09) was statistically less than the Bolton standard (77.2; P<.001). CONCLUSION: The Bolton ratio can be applied to the investigated ethnic groups except for the anterior ratio in Japanese patients.