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Premolar extraction in orthodontics: Does it have any effect on patient's facial height?

Zafarmand AH, Zafarmand MM - J Int Soc Prev Community Dent (2015 Jan-Feb)

Bottom Line: Supposedly, extraction provides some vertical reduction.The results of this study are indicative of no change in patient's facial height with bicuspid extraction.In fact, extrusive effect of all types of tooth movement mostly overcomes the benefits of "wedging effect concept."

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

ABSTRACT

Objectives: Facial esthetics is an important part of the orthodontic treatment. Many cases frequently require premolar extraction, either for relief of crowding or for profile change. Supposedly, extraction provides some vertical reduction. This investigation challenges the clinical effects of such treatment protocols.

Patients and methods: This was a retrospective and quasi-experimental study. Records of 60 patients in their post-pubertal age were randomly selected for this study. The criteria for case selection were: Class II Division I malocclusion with either two upper or four upper and lower first premolars extraction. Patients were not vertical-sensitive type of face. Pre- and post-treatment X-rays were scanned and digitized with Dolphin V 10.0 software. The X-rays of both groups were compared based upon the following cephalometric measurements: Lower anterior facial height (LAFH), Me-PP, Pal-MeGe, LAFH/total anterior facial height (TAFH) × 100, upper anterior facial height (UAFH)/TAFH × 100, U6 to PP, L6 to MP, and U6D-PTV.

Results: In the four bicuspid group, a statistically significant increase was observed in all measurements: 2.53 mm increase in LAFH (P ≤ 0.04), 2.92 mm increase in Me-PP (P ≤ 0.01), 0.65° increase in Pal-MeGe (P ≤ 0.02), 0.66° increase in LAFH/TAFH × 100 (P ≤ 0.01), 1.26 mm increase in U6 to PP (P ≤ 0.02), 1.96 mm increase in L6 to MP (P ≤ 0.002), and 3.06 mm increase in U6D-PTV (P ≤ 0.0001). But a decrease of 0.66° in UAFH/TAFH × 100 (P ≤ 0.01) was observed. In the two bicuspid group, a significant increase was generally recorded: 2.06 mm increase in LAFH (P ≤ 0.05), 1.19° increase in Pal-MeGe (P ≤ 0.02), 1.39 mm increase in L6 to MP (P ≤ 0.002), and 2.37 mm increase in U6D-PTV (P ≤ 0.004).

Conclusions: The results of this study are indicative of no change in patient's facial height with bicuspid extraction. In fact, extrusive effect of all types of tooth movement mostly overcomes the benefits of "wedging effect concept."

No MeSH data available.


Related in: MedlinePlus

The cephalometric landmarks and lines registered on the Dolphin V 10.0 software are depicted on the lateral cephalogram
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Figure 1: The cephalometric landmarks and lines registered on the Dolphin V 10.0 software are depicted on the lateral cephalogram

Mentions: The cephalometric landmarks were registered using Dolphin V 10.0 (Dolphin, California, USA) [Figure 1]. A single examiner was calibrated for cephalometric measurements. Thus, there was no need to use Kappa test agreement to calculate the inter-examiner precision value for the reliability of the study. The angular measurements were saved in separate files for individual patients. The registered 18 measurements comprised the following: SNA, SNB, ANB, Y-axis (SN-Gn), SN-GoGn, PP-MeGo, and SN-MeGo angles, Me–PP distance, posterior facial height (PFH), total anterior facial height (TAFH) (N–Me distance), upper anterior facial height (UAFH) (N–ANS distance), lower anterior facial height (LAFH) (ANS–Me distance), U6 to palatal plane, L6 to mandibular plane, LAFH/TAFH × 100, UAFH/LAFH × 100, PFH/TAFH × 100, and U6D–PTV distance. The values were the average measurements for each variable measured by an orthodontist twice. To reduce the measurement errors, 10 patient records were randomly selected for thorough evaluations after final procedures. For the reliability of procedures, the α-Cronbach test was used for evaluation.


Premolar extraction in orthodontics: Does it have any effect on patient's facial height?

Zafarmand AH, Zafarmand MM - J Int Soc Prev Community Dent (2015 Jan-Feb)

The cephalometric landmarks and lines registered on the Dolphin V 10.0 software are depicted on the lateral cephalogram
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4355853&req=5

Figure 1: The cephalometric landmarks and lines registered on the Dolphin V 10.0 software are depicted on the lateral cephalogram
Mentions: The cephalometric landmarks were registered using Dolphin V 10.0 (Dolphin, California, USA) [Figure 1]. A single examiner was calibrated for cephalometric measurements. Thus, there was no need to use Kappa test agreement to calculate the inter-examiner precision value for the reliability of the study. The angular measurements were saved in separate files for individual patients. The registered 18 measurements comprised the following: SNA, SNB, ANB, Y-axis (SN-Gn), SN-GoGn, PP-MeGo, and SN-MeGo angles, Me–PP distance, posterior facial height (PFH), total anterior facial height (TAFH) (N–Me distance), upper anterior facial height (UAFH) (N–ANS distance), lower anterior facial height (LAFH) (ANS–Me distance), U6 to palatal plane, L6 to mandibular plane, LAFH/TAFH × 100, UAFH/LAFH × 100, PFH/TAFH × 100, and U6D–PTV distance. The values were the average measurements for each variable measured by an orthodontist twice. To reduce the measurement errors, 10 patient records were randomly selected for thorough evaluations after final procedures. For the reliability of procedures, the α-Cronbach test was used for evaluation.

Bottom Line: Supposedly, extraction provides some vertical reduction.The results of this study are indicative of no change in patient's facial height with bicuspid extraction.In fact, extrusive effect of all types of tooth movement mostly overcomes the benefits of "wedging effect concept."

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

ABSTRACT

Objectives: Facial esthetics is an important part of the orthodontic treatment. Many cases frequently require premolar extraction, either for relief of crowding or for profile change. Supposedly, extraction provides some vertical reduction. This investigation challenges the clinical effects of such treatment protocols.

Patients and methods: This was a retrospective and quasi-experimental study. Records of 60 patients in their post-pubertal age were randomly selected for this study. The criteria for case selection were: Class II Division I malocclusion with either two upper or four upper and lower first premolars extraction. Patients were not vertical-sensitive type of face. Pre- and post-treatment X-rays were scanned and digitized with Dolphin V 10.0 software. The X-rays of both groups were compared based upon the following cephalometric measurements: Lower anterior facial height (LAFH), Me-PP, Pal-MeGe, LAFH/total anterior facial height (TAFH) × 100, upper anterior facial height (UAFH)/TAFH × 100, U6 to PP, L6 to MP, and U6D-PTV.

Results: In the four bicuspid group, a statistically significant increase was observed in all measurements: 2.53 mm increase in LAFH (P ≤ 0.04), 2.92 mm increase in Me-PP (P ≤ 0.01), 0.65° increase in Pal-MeGe (P ≤ 0.02), 0.66° increase in LAFH/TAFH × 100 (P ≤ 0.01), 1.26 mm increase in U6 to PP (P ≤ 0.02), 1.96 mm increase in L6 to MP (P ≤ 0.002), and 3.06 mm increase in U6D-PTV (P ≤ 0.0001). But a decrease of 0.66° in UAFH/TAFH × 100 (P ≤ 0.01) was observed. In the two bicuspid group, a significant increase was generally recorded: 2.06 mm increase in LAFH (P ≤ 0.05), 1.19° increase in Pal-MeGe (P ≤ 0.02), 1.39 mm increase in L6 to MP (P ≤ 0.002), and 2.37 mm increase in U6D-PTV (P ≤ 0.004).

Conclusions: The results of this study are indicative of no change in patient's facial height with bicuspid extraction. In fact, extrusive effect of all types of tooth movement mostly overcomes the benefits of "wedging effect concept."

No MeSH data available.


Related in: MedlinePlus