Vertical dimensional changes of the lips in the North American black patient after four first-premolar extractions

Do We Vary from Caucasians! Cephalometric Analysis for Orthognathic Surgery in Chhattisgarhi Population

Aim

The aim of this study is to deduce the cephalometric norms for orthognathic surgery in Chhattisgarh population by comparing with the analysis given by Burstone et al. for hard tissue and Legan and Burstone for soft tissue.

Materials and Methods

Lateral cephalograms of 70 subjects (35 male and 35 female) aged between 18 and 25 years having class I malocclusion, acceptable facial profile were recorded and traced for the analysis and interpretation using landmarks and values given by Burstone's analysis were obtained and further comparison was done for the values obtained for the Chhattisgarh population with that of Caucasians.

Results

Findings of our study were statistically significant as considerable skeletal differences were found between men and women of Chhattisgarh origin compared to Caucasian origin. Many contrasting findings were discovered in our study group from that of the Caucasian population with respect to the maxillo-mandibular relation, vertical hard tissues parameters. Less differences were found in horizontal hard tissue parameters and dental parameters among the two study populations.

Conclusion

The differences found must be kept in consideration during analysis of cephalogram for orthognathic surgeries. Values obtained can be considered to assess deformities and surgical planning to achieve optimal results for Chhattisgarh population.

Clinical Significance

The understanding of normal human adult's facial measurements are important to assess craniofacial dimensions and facial deformities and to monitor postoperative results in orthognathic surgeries. Cephalometric norms can be a beneficial abet to clinicians in ascertaining the patient abnormalities. Norms define the ideal cephalometric measurements for patients based on factors such as age, sex, size and race. It has become apparent over years that significant variations do occur among and between the individuals of different racial origins.

A cephalometric investigation of horizontal lip position in adult Nigerians

OBJECTIVES

The aims of this study were to (1) identify soft tissue cephalometric norms for horizontal lip position in an adult Nigerian population; (2) compare values for Nigerian males and females; and (3) compare Nigerian norms with established norms for Caucasians and other populations.

DESIGN

A cross-sectional descriptive study.

SETTING

Lagos University Teaching Hospital Dental Clinic, Idi-araba, Lagos, Nigeria.

PARTICIPANTS

One hundred students (44 males and 56 females) of the College of Medicine, University of Lagos, aged 18-25 years, of Nigerian ancestry, with a normal class I occlusion and no facial asymmetry.

METHODOLOGY

Lateral cephalometric radiographs of the subjects were taken in natural head position. Radiographs were manually traced and 11 soft tissue cephalometric parameters measured. These were derived from the Steiner, Ricketts, Burstone, Merrifield and Holdaway soft tissue analyses. Male and female values were compared using Student's t-test with a level of significance at P<0·05.

RESULTS

Statistically significant differences were observed between Nigerian males and females in eight of the variables studied, with males having more protrusive upper and lower lips than the females. Variables, which did not vary by sex, were soft tissue facial angle, nose prominence and soft tissue chin thickness. In addition, Nigerian norms were higher than norms reported by Steiner, Ricketts, Burstone and Holdaway for Caucasian populations, while the Z-angle was lower than the norm established by Merrifield.

CONCLUSIONS

Gender-specific soft tissue norms for horizontal lip position should be used for orthodontic treatment planning in Nigerian subjects. Nigerians have more protrusive upper and lower lips compared to Caucasians.

Le facteur ethnique est-il un indicateur thérapeutique?

Face au diktat de la beauté imposée par la société à travers des stéréotypes, il est devenu légitime de s’interroger sur le concept universel du “ beau ”. Est-ce que les normes esthétiques en orthodontie, établies à partir d’échantillons de Nord-Américains, peuvent être applicables à d’autres populations? Les différentes analyses céphalométriques menées chez des sujets afro-américains, africains et asiatiques en occlusion normale non traitée mettent en évidence des critères esthétiques éloignés des critères nord-américains. Leurs conclusions relatent comme principal caractère ethnique la biprotrusion alvéolo-dentaire en relation avec un angle naso-labial réduit. Pour le sujet africain, on note très fréquemment une antéro-position du maxillaire avec une position mandibulaire inchangée ou rétruse. Pour le sujet asiatique, une similitude des profils cutanés est rapportée avec une divergence quant aux profils squelettiques : les Japonais présentent une rétrognathie maxillaire plus prononcée; les Chinois montrent souvent une promaxilie et une rétromandibulie. Les Coréens se rapprocheraient des Japonais. Il semble donc nécessaire de constituer des données spécifiques à l’origine ethnique afin d’optimiser le diagnostic esthétique et les objectifs du traitement orthodontique.

Ethnic differences in upper lip response to incisor retraction

INTRODUCTION

The purpose of this retrospective longitudinal study was to investigate the response of the upper lip to incisor retraction and to ascertain the effect of ethnicity on this response.

METHODS

Pretreatment and posttreatment lateral cephalograms of 88 postpubertal female patients (44 black and 44 white; mean age, 18.45 years) were evaluated. The groups were matched by age and the amount of incisor retraction at incisor superius.

RESULTS

Although significant pretreatment differences existed between the groups in some cephalometric measurements, analysis of the treatment changes demonstrated significant differences only in incisor inclination. Hard and soft tissue changes of the black group were more downward, whereas changes in the white group were more backward. Multivariate regression analysis showed that the horizontal response of the upper lip to hard tissue changes at subnasale and superior labial sulcus was different in whites than in blacks. At subnasale, stepwise multivariate regression analysis showed that ethnicity contributed to the upper lip response to incisor retraction and was significantly greater in the white group.

CONCLUSIONS

The hard and soft tissue treatment changes of the black group were more downward, and those of the white group were more backward. Ethnic differences exist in the soft tissue response to hard tissue changes in the upper lip, and at subnasale and the superior labial sulcus; however, these response differences at superior labial sulcus can be explained by the ethnic differences in initial lip thickness and incisor inclination; they are not due in and of themselves to ethnicity. The change at prosthion was significantly correlated with the response of the upper lip at labrale superius to incisor retraction. Ethnicity added no increase to the predictability of the response. When incisor retraction was performed, the final horizontal upper lip position could be accurately and reliably predicted.

The perceived impact of extraction and nonextraction treatments on matched samples of African American patients

Orthodontic patients of African descent often seek some measure of reduction in profile protrusion. Lip retraction, however, seems to imply a need for premolar extraction. But in a nonextraction era, what does orthodontics have to offer the bimaxillary protrusion patient? To a considerable extent, it depends on what the patient wants and what treatment can provide. The present study was designed to address these questions by comparing the esthetic impact of extraction and nonextraction therapy on two morphologically similar samples of African American patients with Class I and II malocclusions. In addition to the patients, four panels of judges (black and white orthodontists and black and white laypersons) were asked to compare the pretreatment and posttreatment profile tracings and to quantify their perceptions of the esthetic impact of the change that occurred during treatment. Although there was a strong correlation among the various groups' ratings, there were a number of statistically significant differences. Premolar extraction led to a modest reduction in dental and soft tissue protrusion; nonextraction, by way of contrast, produced an increase. Presumably in response to these changes, all panels, independent of race or education, tended to prefer the posttreatment profiles, especially the posttreatment extraction profiles. There was, however, a significant interaction between race and treatment. The perceived effects of nonextraction treatment were modest and largely unrelated to the pretreatment profile, whereas the impact of premolar extraction was a highly significant function of initial protrusion: convex profiles were improved, but relatively straight profiles were made worse. The various panels, however, differed in their estimate of the point at which a profile might benefit from extraction (ie, profile reduction). For our white panelists, that point was reached when the lower lip was about 2 mm in front of Ricketts' E-plane. For our black panelists, the equilibrium point came at +4 mm. These findings imply that there is significant interaction among the type of treatment, the race of the patient, and both the race and professional background of the observer. Facial beauty, it would seem, is in the hand of the orthodontist, as well as in the eye of the beholder and the face of the beheld.

Long-term comparison of extraction and nonextraction alternatives in matched samples of African American patients

African American orthodontic patients often present with morphologic characteristics that prompt the extraction of premolars. Referring dentists, however, commonly see extraction as a cause of "dished in" profiles, collapsed arches, and temporomandibular dysfunction. If true, these claims imply that African American patients are disproportionately at risk of clinical misadventure. Unfortunately, a meaningful long-term comparison of alternative treatments--be it retrospective or prospective--requires samples of patients who were equally susceptible to the two alternatives. Thus, if a retrospective study is to be free of susceptibility bias, the samples must be matched with respect to the anatomic differences that prompted the clinicians' choice of treatments. The goals of this investigation, therefore, were the following: to gather a large sample of African American expatients and to identify by means of discriminant analysis the characteristics that seem to have been important to the extraction decision, to use this knowledge to assemble subsamples of extraction and nonextraction expatients (both Class I and II) who were similar before treatment, and, finally, to recall them so that the long-term impact of the two strategies could be compared. In the end, 60 expatients--30 extraction and 30 nonextraction--were recalled, on average, nearly 8 years after the completion of treatment. In general, both treatments reduced irregularity and neither seemed to produce posterior mandibular displacement. Premolar extraction led to a modest reduction in dental and soft tissue protrusion (half the incisor retraction minus one); nonextraction, by way of contrast, produced an increase. Long term, the difference between the two treatments was about 2 mm at the upper lip and 4 mm at the lower. Excessive profile flattening was not a common finding. Our findings thus imply that the various "functional orthodontic" arguments against premolar extraction do not apply to African Americans any more than they do to whites.