Mehta Pooja, Sagarkar Roshan M, Mathew Silju
Postgraduate Student, Department of Orthodontics, MS Ramaiah Dental College and Hospital, Bengaluru, Karnataka, India.
Reader, Department of Orthodontics, MS Ramaiah Dental College and Hospital, Bengaluru, Karnataka, India.
J Clin Diagn Res. 2017 Jun;11(6):ZC60-ZC64. doi: 10.7860/JCDR/2017/25042.10075. Epub 2017 Jun 1.
Cephalometry has many limitations of which radiation exposure is most important. Hence, there is a need to resort to other safer methods which could give equal if not better results.
The purpose of this study was to compare and correlate the craniofacial measurements obtained from cephalometric radiographs and analogous measurements from standardized facial profile photographs in skeletal class II cases.
A total of 30 lateral cephalograms and profile photographs of patients exhibiting skeletal class II malocclusion, in the age group of 19-25 years of age, were examined in this study using Dolphin software (version 11.8). A standardized protocol was followed for all the lateral cephalograms and photographs. A total of 15 parameters were studied in this study out of which seven were angular and eight were linear parameters. Angular parameters included Frankfort Mandibular Plane Angle (FMA), Mandibular Plane-Occlusal Plane (MP-OP) angle, Occlusal Plane (OP) angle, gonial angle, ANB angle, facial angle and convexity whereas linear parameters included Anterior Facial Height (AFH), Ramal height, Posterior Facial Height: Anterior Facial Height (PFH/ AFH), convexity (in mm), Nasion perpendicular- Point A, Nasion perpendicular- Pogonion, Witts and Mandibular body length. All these parameters were digitised on both the cephalogram and photographs and were compared using one sample-2 tailed t-test, Pearson correlation coefficient. Bland-Altman Plot was considered to find comparison between the measurements from photographs and cephalograms in skeletal class II patients.
On comparing the angular cephalometric and photographic variables for the skeletal class II subjects we found the cephalometric parameters like FMA, MP-OP angle, OP, gonial angle, convexity (in degrees) to have an insignificant difference compared to the analogous photographic measurements. On comparing the linear cephalometric and photographic variables, it was found that all the cephalometric parameters like AFH, ramal height, PFH/AFH, N perp-Point A, N perp-Poghad a good relationship with the analogous photographic measurements.
The photographic method can be considered as a repeatable and reproducible method if a homogeneous protocol is followed. Thus, photographic measurements may reflect to be a rational and practical diagnostic substitute to measurements obtained from cephalograms in Class II malocclusion subjects.
头影测量有许多局限性，其中辐射暴露最为重要。因此，有必要采用其他更安全的方法，这些方法即使不能产生更好的结果，也能给出相同的结果。
本研究的目的是比较并关联骨骼II类病例中从头影测量X线片获得的颅面部测量值与标准化面部侧位照片的类似测量值。
本研究使用Dolphin软件（版本11.8）检查了19至25岁年龄组中表现出骨骼II类错牙合的30名患者的侧位头影测量片和侧位照片。对所有侧位头影测量片和照片均遵循标准化方案。本研究共研究了15个参数，其中7个为角度参数，8个为线性参数。角度参数包括法兰克福下颌平面角（FMA）、下颌平面-牙合平面（MP-OP）角、牙合平面（OP）角、下颌角、ANB角、面角和凸度，而线性参数包括前牙高度（AFH）、升支高度、后牙高度：前牙高度（PFH/AFH）、凸度（以毫米为单位）、鼻根垂线至A点、鼻根垂线至颏前点、Witts值和下颌体长。所有这些参数在头影测量片和照片上都进行了数字化处理，并使用单样本双侧t检验、Pearson相关系数进行比较。采用Bland-Altman图来比较骨骼II类患者照片和头影测量片的测量结果。
比较骨骼II类受试者的角度头影测量和摄影变量时，我们发现与类似的摄影测量相比，FMA、MP-OP角、OP、下颌角、凸度（以度为单位）等头影测量参数差异不显著。比较线性头影测量和摄影变量时，发现所有头影测量参数，如AFH、升支高度、PFH/AFH、鼻根垂线至A点、鼻根垂线至颏前点，与类似的摄影测量都有良好的相关性。
如果遵循统一方案，摄影方法可被视为一种可重复的方法。因此，在II类错牙合受试者中，摄影测量可能是一种对头影测量结果合理且实用的诊断替代方法。
