INTRODUCTION

During the past decade, great concern has been drawn toward facial esthetics as one of the major goals of orthodontic treatment.1–3 Consequently, evaluation of proportional facial features is a prerequisite for achieving pleasant facial esthetics. Cephalometric analyses of soft tissues are among the most accurate and reproducible tools for evaluating the profile.4–7 Profile assessment is based on both linear and angular measurements performed on the radiographic image. Norms of desirable esthetic profiles have been established for various populations.8–12 Several studies have described profile changes when various orthodontic treatments or orthognathic procedures were completed.13–17

The use of cephalometrics is critical in the diagnosis of dental and skeletal malocclusion; it also is used for soft tissue profile analysis. The soft tissue facial profile can be assessed by means of standardized photographic records as well.18–23 This method requires accurate standardization of the photographic setup; only when this is provided can both angular and linear measurements be calculated.

Establishing a reproducible soft tissue profile analysis based on conventional dental photographs is difficult because it is important to achieve standardization for pictures taken under different photographic conditions. However, conventional nonstandardized photographs of a soft tissue profile offer several advantages, such as no radiation (compared with soft tissue radiograms), availability (performed in-house without the need for specific photographic equipment), low expense (the use of standard cameras), and versatility (open and closed lips, semiprofile, and smiling).

To the best of our knowledge, the possible effect of increased lip posture caused by labial attachment had never been investigated. Nevertheless, it is stated that one advantage of lingual orthodontics is that that the brackets do not affect lip posture as labial appliances do.24

Thus, the first aim of this study was to establish an accurate and reproducible photoanalysis of soft tissue profile based on conventional profile photographs. The second purpose of this experiment was to compare upper lip posture before and immediately after debonding of labial appliances, so as to evaluate the effects of bonded labial appliances on lip posture.

MATERIALS AND METHODS

Establishing the Photoanalysis

Facial clinical profile photographs of nine teenagers (five males and four females) undergoing orthodontic treatment with labial appliance Mini Diamond Roth prescription 0.022-inch slot width (Ormco, Orange, Calif) were used. Each patient was photographed twice with a 30-minute interval between pictures. At each time point, two sets of consecutive photographs were taken, and the best picture of the two was chosen.

All photographs were taken with a digital camera (Olympus 620L, Olympus America Inc, Center Valley, Pa) with the high-quality option under nonstandard conditions (the camera was not mounted on a tripod but was hand held by the photographer; the distance from camera to patient was not measured; no special requirements were applied for the head position). The only criterion was that patients were instructed to keep their teeth and lips in light contact. The technical details were as follows: resolution of 144 pixels/inch (DPI) in a true color mode (RGB—24 bits), working size of the file of 3840 kb, picture dimensions of 7.11 w/8.89 h inches (18.06/22.58 cm); the pictures were saved in JPG format with a compression ratio of 19.2 (file size, 200 kb). All pictures were viewed on full screen (1024 × 768 pixels) without distinguishing pixelization.

All pictures were examined by custom-made analysis (photoanalysis model) with the use of commercial cephalometric software (Viewbox, dHal Software, Kifissia, Greece), version 3.0.0.10.25

The following landmarks were identified on the profile photographs (Figure 1):

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1. Center of tragus.

2. Outer canthus (lateral intereyelid junction).

These two points were used to construct the reference line (tragus–canthus line).

3. Nasion-modified: the point where the elongated reference line intersects with the profile

4. Subnasale

5. A′: soft A point

6. Upper lip: the most prominent point of the upper lip—modified vermilion

7. Lower lip: the most prominent point of the lower lip—modified vermilion

8. B′: soft B point

9. Pog′: soft pogonion

Enlargement up to three times was applied to the photographs, if needed to assist with landmark identification.

RESULTS

Establishing the Photoanalysis

No significant differences were found in all six angular measurements between the two consecutives photographs (T-0/T-0′, T-30/T-30′) (Table 1; Figure 2).

• T-0 (initial measurements)

• T-0′ (measurements of the same picture after 45 days)

• T-30 (initial measurements of picture after 30 minutes)

• T-30′ (measurements of the 30-minute picture after 45 days)

Table 1.  Differences Between Two Sets of Photographs With 0 Time Interval^a

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Comparison of average angular measurements in photographs at the two time points (T-0 + T-0′ vs T-30 + T-30′) showed no significant differences between them (Table 2).

Table 2.  Comparison of Photographs With 30-Minute Intervals Without Treatment^a

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Effects of Labial Appliances on Lip Prominence

The two angular measurements describing lip prominence (upper vermilion and lower vermilion) showed no differences before and after debonding (Table 3; Figure 3).

• T-0 (pre-debonding measurement)

• T-0′ (pre-debonding measurements of the same picture after 45 days)

• T-30 (immediately after debonding measurements)

• T-30′ (debonding measurements of the same picture after 45 days)

Table 3.  Comparison of Photographs With 30-Minute Intervals Before and After Debonding^a

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No differences were found between the other four angular measurements before and after debonding (Table 3; Figure 3). The sub-nasale angle showed a large variation in measurements before and after debonding, although this variation was not statistically significant.

DISCUSSION

A new soft tissue profile photoanalysis is described in the present study. This method, performed with Viewbox software, can provide supplementary data and should not replace common soft tissue cephalometric measurements.

It is important to emphasize that the analysis is based on the major finding that all angular measurements formed from the various landmarks were accurate and reproducible at different time points of photography. These findings also suggest that identification of anatomic landmarks is easy, and that probably no significant errors occurred in the vertical or the horizontal plane. However, the angle created by sub-nasale showed large variation, most probably because of the fact that this point is located on a more horizontal envelope of error.26

This study focused on angular changes as they correspond to postural changes in the lips, but it is possible to assess other tissues, such as nose and chin, by constructing the relevant angular planes. It will be of great interest to compare this profile photoanalysis with corresponding cephalometric landmarks, and furthermore, to evaluate the effects of different treatment modalities, age changes, various ethnic populations, and so forth, on soft tissue photographic profiles.

The advantages of a photographic image over a radiographic one are obvious, and it is suggested that the ability of this soft tissue photoanalysis to substitute corresponding cephalometric measurements must be the topic of comprehensive comparative studies. In the meantime, this type of photoanalysis may be used as an additional clinical tool.

Results of photoanalysis showed that labial appliances bonded on the upper anterior teeth do not affect lip prominence. Patients who participated in this study were not subdivided according to lip thickness or dimensions of the brackets because at this stage of the research, we were interested in lip posture of the same patient with and without brackets. Obviously, comparisons between all possible variants are required.

The notion that lingual orthodontics is superior to the labial technique in terms of lip prominence is rejected, given the results of the present work. Orthodontists can be certain that lip posture at the end of treatment prior to debonding will not change in the short range following removal of appliances. Thus, the orthodontist can reassure the patient that no reclining sinking of the lips will occur after removal of the braces. An additional study undertaken to examine the long-term effects of labial bracket removal on lip position is in progress.

This study presented one application of simple soft tissue photoanalysis. In the future, it might be feasible to extend the use of these computer-processed photographic principles to other photoanalyses.

CONCLUSIONS

• Angular measurements used in this photoanalysis were validated as reproducible.

• In keeping with the design of this study, bonded labial appliances had no significant effect on lip prominence in the short term after debonding.