Constancy of the angle between the Frankfort horizontal plane and the sella-nasion line: A nine-year longitudinal study

Objective: To investigate the constancy of the angle between the Frankfort horizontal plane (FH) and the sella-nasion line (SN) using longitudinal data.Materials and Methods:Longitudinal lateral cephalometric data of 223 children (116 girls and 107 boys) from 6 to 14 years of age were used. The angle between FH and SN (SNFH), the distance from FH to the nasion (NFH), the distance from FH to the sella (SFH), and the differences between the NFH and SFH (Δ) were also measured. All data were analyzed statistically using independent t-tests and mixed-effect regression model analysis.Results:The mean SNFH values showed some minor fluctuations, ranging from 9.26° to 9.74° in girls and 8.45° to 8.95° in boys. The mean NFH and SFH values gradually increased according to age irrespective of sex. There were statistically significant differences by sex for all measurements at several ages. The annual change in SFH and Δ showed sexual dimorphism.Conclusions:There are variations among individuals in the angle between the FH and SN. However, within an individual, the angle does not vary significantly over time during the observation period.     

头颅矢状水平向平面角与面部生长型的相关研究

目的 研究面部生长型与头颅矢状水平向平面解的关系。验证面部后前面高比的诊断意义。方法 摄取６５ 青年恒牙Ｈｅ头颅侧位Ｘ一片,计算机图形分析系统出包括ＰＰ、ＭＰ、ＯＰ、ＳＮ平面在内的七顶测量值及后前面高比值,并进行相应统计学分析。结果 ①四个水平向平面角（ＯＰ－ＦＨ,ＭＰ－ＦＨ,ＰＰ－ＦＨ,ＳＮ－ＦＨ）与后前面高比呈负相关,确定系数９０．７％。②上下颌面角与后前面高比值有极高相关性,确定系数为６８．     

两种拔牙模式矫治后相关平面的变化研究

目的研究拔除4颗第一前磨牙（上四下四）和拔除双侧上颌第一前磨牙和下颌第二前磨牙（上四下五）2种拔牙模式矫治前后腭平面、平面及下颌平面的变化。方法固定正畸矫治患者166例,拔除上四下四62例,拔除上四下五7 6例,不拔牙2 8例,测量矫治前后的腭平面角、咬合平面角和下颌平面角等项目。结果 2种拔牙模式患者腭平面和平面的变化差异无统计学意义;拔除上四下四矫治的均角型患者矫治后下颌平面角轻微增加（t=2.97,P〈0.05）;其余患者的改变差异没有统计学意义。结论拔除上四下四和拔除上四下五2种拔牙模式不会导致腭平面、平面的改变,拔除上四下四矫治的均角型患者下颌平面角轻微增加。     

Reliability of Anatomic Reference Planes in Establishing the Occlusal Plane in Different Jaw Relationships: A Cephalometric Study

The purpose of this study was to evaluate the reliability of different anatomic reference planes in determination of Occlusal plane in dentulous and edentulous subjects with Angle’s class I and class II Maxillomandibular relationship. Eighty subjects were included in the study which was divided into four Groups based on dentition and skeletal relationship. The Group I (n = 20) and Group II (n = 20) includes young and completely dentulous subjects in Angle’s class I and class II relationship, respectively. The Group III (n = 20) and Group IV (n = 20) subjects were completely edentulous in Angle’s class I and class II relationship, respectively. For all subjects, right lateral cephalograms were taken and cephalometric analysis was done and data obtained from cephalometric tracings were then statistically analyzed. The results showed no significant difference of angle between Occlusal plane and Frankfort Horizontal plane, Camper’s plane and Palatal plane when Group I and Group III, and Group II and Group IV subjects were compared. The Frankfort Horizontal plane, Camper’s plane and the Palatal plane may be used as a reliable guide to establish Occlusal plane in edentulous subjects in both Angle’s class I and class II Maxillomandibular relationships.     

Assessment of mesiodistal tooth angulation on the panoramic radiograph

Tilting of the head has been suggested as a potential source of error when the clinician assesses the angulation of teeth in the panoramic radiograph. If a reference line that could be stable in variations of head positioning during the radiographic exposure could be found, then the examination of the radiograph would be more accurate. We examined the effects of three different head positions on the panoramic image in ten volunteer patients. Our findings suggest that the upper and lower margins of the film are useful reference lines in estimating the mesiodistal angulation of six anteriors, and the mandibular plane is more useful in assessing the angulations of posterior teeth and canines.     

Orientation of craniofacial planes and temporomandibular disorder in young adults with normal occlusion

The aim of this study was to investigate the relationship between orientation of craniofacial planes relative to the true horizontal and temporomandibular disorder (TMD), in normal occlusion. Fourteen university dental students, with full natural dentition and bilateral Angle Class I occlusion, who exhibited signs and symptoms of TMD, were compared with 14 age- and sex-matched healthy controls. Frontal and lateral photographs were taken in natural head position with the subject standing up, clenching a Fox plane and having a facial arch positioned. Photographs were examined by a standardized image analysis. Inter-pupillary axis, Frankfurt, occlusal and Camper planes were evaluated. In frontal view, the Frankfurt plane was right rotated relative to the true horizontal both in TMD subjects (P < 0.01) and controls (P < 0.05), but rotation was larger in TMD subjects (mean difference between groups, 1.1 degrees, 95% confidence interval, 95% CI, 0.2-2.0 degrees ). No significant deviation from the horizontal or difference between groups was observed for the interpupillary axis and occlusal plane. In lateral view, the Frankfurt plane was upward-orientated relative to the true horizontal in TMD group (mean angular deviation 2.8 degrees, 95% CI, 1.0-4.6 degrees ). The occlusal and Camper planes were downward-orientated in both groups (P < 0.0001), but inclination of occlusal plane tended to be smaller in TMD subjects (mean difference between groups, -3.8 degrees, 95% CI, -7.6-0.1 degrees ). Angles between any craniofacial planes did not significantly differ between groups. The findings show that in young adults with normal occlusion, a weak association exists between the orientation of craniofacial planes in natural head position and signs and symptoms of TMD. Furthermore, they suggest that, within this population, TMD might be mainly associated with head posture rather than with craniofacial morphology.     

“Occlusal Plane Orientor”: An Innovative and Efficient Device for Occlusal Plane Orientation

Correct occlusal plane orientation is a prerequisite in Prosthodontic reconstructive treatment therapy as it helps in achieving esthetics and phonetics anteriorly and forms a milling surface posteriorly where tongue and buccinator muscle position the food bolus during mastication. Activity of Muscles during clenching will be least, when the occlusal plane is made parallel to plane of lost natural teeth. Conventionally the ala-tragus line (Camper’s plane) is used as a guide for assessment of the occlusal plane and fox plane is used to check the parallelism between the two. Occlusal plane orientor is a new device developed to mark occlusal plane parallel to ala-tragus line on maxillary occlusion rim, thereby saving clinician’s time and increasing efficiency. Additionally, it is a useful tool for occlusal plane orientation in patients with facial deformity, absence of an eye or an ear.     

Repair of untreated horizontal root fracture: a case report

Abstract  – We report a clinical case of horizontal root fracture in the mandibular first premolar induced by a traffic accident. The fractured tooth spontaneously healed and diagnosed radiographically after 2 years. Fractured fragments were separated by a narrow radiolucent line and the edges were rounded, and healing of the tooth is likely to be related to interproximal connective tissue healing. Our case is an example of spontaneously healed fracture roots. An interesting finding is that the healing was observed even in the presence of two root canals, the vitality of the pulp was preserved and displacement of fragments were prevented.     

Three-dimensional analysis of the occlusal plane related to the hamular-incisive-papilla occlusal plane in young adults

The planes which serve as references for cranium and face in dental clinical application included the occlusal plane, Frankfort plane, Camper's plane and hamular-incisive-papilla (HIP) plane. The HIP occlusal plane is a horizontal plane passing through the bilateral hamular notches and the incisive papilla (Dent Surv. 1975;51:60). The aim of this study was to estimate the relationship between the various occlusal planes and the HIP plane in Taiwanese young adults with approximately optimal occlusion. Study casts of 100 young adults (50 men and 50 women) were selected in this study. All market points on the maxillary casts were measured by a three-dimensional precise measuring device. The angular relationship between the four various occlusal planes and the HIP plane were investigated. The vertical distances between the cusp tips and incisal edges of maxillary teeth to the HIP plane were measured. Data were performed by the Statistic analysis software programme (JMP 4.02). The Student's t-test and Pearson's correlation test were used to test the statistical significance (P < 0.05). The results showed that the occlusal plane defined as the incisal edge of maxillary central incisor to mesiobuccal cusp tips of maxillary second molars had the smallest included angle with the HIP plane (2.61 +/- 0.81 degrees). The incisal edge of maxillary right central incisal to mesiopalatal cusp tips of maxillary first molars had the largest included angle with the HIP plane (7.72 +/- 1.60 degrees). The curve is drawn through the buccal cusp tips of maxillary teeth had better parallelism with the HIP plane.     

经验丰富医师和初级医师使用咬合平面板确定全口义齿咬合平面的精度比较

目的：比较经验丰富的口腔医师和初级医师使用咬合平面板确定全口义齿咬合平面的准确性。方法15位经验丰富的医师和15位初级医师分别使用咬合平面板确定仿真头颅模型蜡堤的咬合平面,测量蜡堤上咬合平面与参考平面的夹角,分析2组测量值之间的差异。结果经验丰富的医师和初级医师所确定的前牙区咬合平面与参考平面的夹角分别为(0.2±0.1)°和(0.6±0.2)°,差异有统计学意义(t=-4.668,P<0.001),但夹角都接近于0°,差异无临床意义。经验丰富的医师和初级医师所确定的后牙区咬合平面与参考平面的夹角分别为(0.9±0.4)°和(3.4±0.6)°,差异有统计学意义(t=-13.378,P<0.001),经验丰富的医师所确定的咬合平面与参考平面的夹角更接近0°。结论对于经验丰富的口腔医师,使用咬合平面板确定咬合平面是一种精度较高的方法。初级医师使用咬合平面板确定前牙区咬合平面也很准确,但对后牙区咬合平面的观测能力较差,需要在这方面加强训练。     

青少年病例正畸治疗前后下颌平面旋转的纵向研究

目的:探讨下颌平面在正畸矫治前后及保持阶段的变化.方法:本研究资料选自2001～2005年间在温州医学院附属口腔医院正畸科就诊的门诊病例,其中安氏Ⅰ类14例,女11例,男3例;安氏Ⅱ类10例,女8例,男2例;年龄分布在12～13岁,平均年龄12岁零3个月,平均疗程1年零8个月,平均保持时间1年零6个月.分别在矫治前(T1),矫治结束时(T2)、保持1年以后(T3)3个阶段拍摄X线头颅侧位片,利用winceph7软件进行头影测量.结果:治疗期间下颌平面呈现顺时针旋转,＜Y-SN增加了0.73°,有显著性意义.保持期间＜Y-SN减少了0.26°,但没有统计学意义.结论:正畸治疗对青少年病例下颌骨生长存在一定影响,造成下颌骨顺时针旋转,并且在保持结束时没有恢复至原有水平.     

Spontaneously healed horizontal root fracture in maxillary first premolar: report of a case

Abstract –  Root fractures of the posterior teeth are rare and occur as a result of severe trauma. This study describes the horizontal root fracture of a maxillary first premolar. The fractured roots were discovered during a routine radiographic examination. The tooth was asymptomatic and responded positively to electric pulp testing. The patient reported accidental trauma, which occurred 14 years before. Our case is an example of spontaneously healed fractured roots. The interesting findings were that the healing was observed even in the presence of two roots, including preservation of the vitality of the pulp.     

Management of occlusal canting with miniscrews

A 14-year-old boy with a skeletal Class II malocclusion and open bite whose chief complaint was a posterior crossbite showed a canted occlusal plane with asymmetric gummy smile and mandibular deviation at clinical examination. The treatment with miniscrews focused on the bilateral intrusion of the maxillary posterior teeth and, after resolving the open bite, a new biomechanical technique involving joined miniscrews was applied for an en masse intrusion of the left side. This treatment strategy achieved optimal occlusion with improvements to the sagittal, vertical, and transverse relationships and achieved a harmonious smile.     

平面与下颌矢状向位置关系的 X线头影测量研究

目的明确下颌处于不同矢状向位置时的牙形态,以及下颌矢状向位置与平面倾斜度的关系,为下颌矢状向位置异常患者的非手术正畸治疗提供策略依据。方法选取114例女性正畸患者治疗前的114张头影侧位片,根据ANB角的大小分为3组,每组各测量25项指标。对3组之间及两两组之间的差异进行方差分析和多重比较分析,对骨性指标与牙性指标的相关性进行直线相关分析。结果后牙平面（OP-P）倾斜度和上颌第二磨牙的垂直高度与下颌矢状向位置相关（P<0.05）。下颌后缩时,上颌第二磨牙垂直向萌出相对不足,OP-P倾斜度增加;下颌前伸时,上颌第二磨牙垂直向萌出相对过度,OP-P更平坦。当下颌处于不同位置时,牙轴近远中倾斜度有不同的代偿。下颌后缩患者上颌牙列牙轴远中倾斜,下颌牙列牙轴近中倾斜;下颌前突患者上颌牙列牙轴近中倾斜,下颌牙列牙轴远中倾斜。结论不同骨性环境下形态各有不同,正畸治疗下颌位置异常的患者时应重视后牙垂直高度的控制和对OP-P倾斜度的改变。     

40例双颌前突患者头影测量分析

目的探讨双颌前突患者的颅面特征，为临床诊治提供参考。方法用审美平面检出40例双颌前突患者（其中青少年组20例，成年组20例，每组男、女各半），对其头颅侧位定位片进行描图，通过计算机辅助多功能容貌测量系统软件定点、测量。结果青少年组与成年组相比，青少年组随年龄增长面下部有显著生长，且以前颅底后部及下颌后部生长明显，上颌基骨生长不显著；女性组与男性组相比，女性前颅底相对短，下颌角较大，上唇软组织突度较明显；与北京、华西正常[牙合]相比，双颌前突患者均显示下颌骨位置相对后缩，切牙过度唇倾。结论对需要通过矫形力来抑制颌骨过度发育而达到矫治双颌前突目的的患者，应从青春期前进行；矫治女性双颌前突患者更应内收上前牙，以改善上唇过突导致的不美观；用审美平面检出的双颌前突患者不仅仅表现为上下颌骨和（或）牙的前突，还可表现为下颌相对后缩。     

机械耳点和解剖耳点的相对位置关系研究

目的：对机械耳点和解剖耳点的相对位置关系进行测量分析,探讨两点不一致产生的原因.方法：选择正畸初诊患者124例,男42例,女82例,平均年龄11.3岁.用西门子Orthophos3型X光机拍摄头颅定位侧位片.以机械耳点最上缘为原点,以FH平面为X轴,建立直角坐标系.将全部病例两耳点位置关系描记于同一张描图纸上.结果：①解剖耳点和机械耳点的完全重叠率仅为20.1%;②.两点间相对位置关系有4种表现形式;③.解剖耳点多位于机械耳点后上方,散布于90°～150°范围内,距机械耳点最大垂直距离为15.1 mm,最大水平距离9.0 mm,平均向后2.3 mm,向上8.9 mm,平均距离9.2±3.89 mm.结论：外耳道的解剖结构决定了解剖耳点与机械耳点的不一致.在临床中,要根椐选择分析法的不同而选择相应的耳点.     

[牙合]平面的研究进展

平面是影响口颌系统功能的重要因素之一。对患者进行口颌功能修复或重建时,确定适宜的平面是重要的一步。本文结合国内外学者的研究状况,对平面的定位及其影响因素、平面与口颌系统的关系以及平面与颈椎的关系等进行综述。     

重度阻塞性睡眠呼吸暂停低通气综合征多平面阻塞同期手术治疗效果评价

目的 观察存在上气道结构性狭窄的重度阻塞性睡眠呼吸暂停低通气综合征（obstructive sleep apnea-hypopnea syndrome, OSAHS）鼻、口咽、喉咽多平面阻塞同期手术的治疗效果,探讨提高OSAHS疗效、减少复发的经验。方法 2008年4月—2013年12月,对21例严重OSAHS患者通过临床检查和Alice 5多导睡眠监测仪监测（PSG）,术前睡眠呼吸暂停低通气指数（AHI）58.8~74.0,平均67.8,SaO₂最低0.25~0.67,平均0.46,最长睡眠呼吸暂停时间52~77 s,平均63.3 s。全麻下同期完成鼻腔扩容手术、腭垂腭咽成形术（uvulopalatopharyngoplasty, UPPP）、腭扁桃体切除手术;颏部“开窗”、“凸”形或“梯形”截骨,前徙颏部及颏舌肌和舌骨上肌群的颏前徙术;舌骨下肌群切断、舌骨悬吊术。气管插管维持24~48 h。结果 经过8~68个月随访,21例手术创口均一期愈合,睡眠呼吸障碍症状消除或明显减轻,8例打鼾消失,13例仰卧位时仍有轻、中度鼾声,均无睡眠憋醒现象,同期颏成形患者对外形改善满意。PSG监测术后AHI10.2~24.2,平均20.3,SaO₂ 0.82~0.99,平均0.91,最长呼吸暂停时间11~35 s,平均17.9 s。结论 存在上气道结构性狭窄的重度OSAHS采取同期多平面手术治疗,可明显提高治疗效果且缩短疗程,经治病例均获得较满意疗效。     

Evaluation of Facial Asymmetry Using Digital Photographs with Computer Aided Analysis

Facial asymmetries exist in all individuals. Due to these facial asymmetries that exist, a standardized approach in locating the occlusal plane that is parallel to the ala-tragus and interpupillary lines, may result in less than ideal esthetics in the final restoration. The challenge for the prosthodontist is to determine an acceptable occlusal plane with an individualized approach that can be used as a guide for alignment of the maxillary anterior teeth in cases that require their replacement or extensive restoration. The present study uses an inexpensive and standardized digital photographic technique along with computer assisted analysis to measure the asymmetries of the human face. Statistical Analysis used-Karl pearson’s correlation coeffient was used. The correlation coefficient was then subjected to ‘t’ test and ‘p’ value was used to find out the level of statistical significance. Left side of the face was found to be at a higher level than the right side.

Electronic supplementary material

The online version of this article (doi:10.1007/s13191-011-0087-4) contains supplementary material, which is available to authorized users.