Relationships of sagittal skeletal discrepancy,natural head position,and craniocervical posture in young Chinese children

Objective: The aim of this study was to investigate the relationships of sagittal skeletal discrepancy, natural head position (NHP), and craniocervical posture in young Chinese children with average vertical facial pattern.

Methods: Ninety patients with average Frankfort mandibular plane angle (FH/ML) were classified into skeletal class I, II, and III relationships according to their ANB angle. Cephalometric radiographs in NHP were taken. Variables representing sagittal and vertical craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Subjects in the skeletal class II group showed the largest craniovertical angles and craniocervical angles, while subjects in the skeletal class III group exhibited the smallest craniovertical angles and craniocervical angles, though not all the measurements showed significant differences. The angle formed by the nasion-sella line and the tangent to the posterior border of the mandibular ramus (NSL/RL) was largest in the skeletal class II group and smallest in the skeletal class III group (p?=?0.05).

Discussion: Significant differences exist in NHP and craniocervical posture among skeletal class I, II, and III relationships in young Chinese children. Subjects with skeletal class II relationship tended to exhibit more extended head, and children with skeletal class III relationship often exhibited flexed head.     

正常汉族成年人前牙区牙槽宽度及根尖位置的研究

目的研究正常[牙合]成人前牙根尖与周围骨皮质的位置关系，为正畸矫治设计、筛选根吸收高危人群和预防医源性并发症等提供指导。方法选择正常拾青年98人，男女各半，年龄范围17～25岁，平均年龄20．29岁。拍摄头颅侧位定位片，测量并计算反映上下颌切牙根尖到周围骨皮质位置关系的12项指标及下颌平面角。建立上述测量指标的均值范围；相关分析研究下颌平面角对其影响。结果（1）建立正常[牙合]男女根尖位置及牙槽宽度的均值。（2）男性组中SN／MP与UH、UH／UW正相关，与UP负相关；女性组中SN／MP与LW负相关。结论（1）正常汉族成年人上下颌前牙牙槽骨宽度及根尖相对皮质骨位置比较稳定。（2）下颌平面角对根尖位置及牙槽宽度有一定影响。     

A simple classification of facial asymmetry by TML system

This study proposes a system for classifying facial asymmetry with accompanying mandibular prognathism to facilitate choice of surgical method. We examined hard and soft tissue measurements obtained from posterior–anterior cephalometric radiographs and clinical facial photographs of 153 patients (86 male, 67 female), classifying them according to menton deviation with transverse asymmetry (T), maxillary cant (M), and lip cant (L). The T-group is subclassified according to direction of transverse asymmetry (H). Statistical analysis of menton deviation, cant and transverse asymmetry was performed for each group. The various relationships observed among the groups indicate that most cases (85%) were not effectively correctable using conventional surgical methods. As such, the authors believe that analysing facial asymmetry in terms of the classification system presented in this study and employing surgical methods appropriate to each case will help achieve more harmonious aesthetic outcomes.     

Reliability of cranial base measurements on lateral skull radiographs

Authors – Arponen H, Elf H, Evälahti M, Waltimo‐Sirén J Objective – To explore the reliability of identification of anatomic landmarks on lateral skull radiographs of young unaffected individuals that has conventionally been used to diagnose pathologic relationships in the craniovertebral junction. Material and Methods – From the Helsinki longitudinal growth study, 20 randomly selected lateral radiographs were analyzed and re‐analyzed by two examiners. Both located seven cephalometric landmarks based on which five measurements were calculated. The differences of results were compared. With similar method three radiographs were analysed by 11 examiners and results were compared. Results – Some anatomic landmarks were easier to locate than others on lateral skull radiographs leading to differences in measurements based on them. We found the magnitude of the difference to be dependent on the landmark serving as reference. Inter‐ and intra‐examiner errors were of similar magnitude, although intra‐examiner error declined in the repeated landmark identification. Variation in a single landmark location had in general little effect on the measurement value. Conclusion – Variations in landmark location lead to differences in numeric evaluation of the anatomic relationships in the skull base area. These differences were, however, shown to have little clinical significance. Hence, the documented methods are applicable for screening of basilar pathology.     

X-ray cephalometric characteristic of face soft tissue profile in orthognatic bite

Article describes some important features of soft tissue profile. A comprehensive cephalometric analysis of "normal" adults was accomplished by examining 67 adults with orthognanic bite. Large number of soft-tissue, dental and skeletal measurements were analyzed and evaluated. The purpose of this study was to assess the features of relationships between hard and soft tissue profile of face, and correlation between separate parameters of them was found.     

Soft Tissue Cone‐Beam Computed Tomography: A Novel Method for the Measurement of Gingival Tissue and the Dimensions of the Dentogingival Unit

ABSTRACT

The dimensions and relationships of the structures of the dentogingival unit have been greatly overlooked because of the inability to easily and precisely determine them. The purpose of the present study was to develop a soft tissue cone‐beam computed tomography (ST‐CBCT) to improve soft tissue image quality and allow the determination of the dimensions and relationships of the structures of the dentogingival unit. Two separate CBCT scans were obtained from three patients with different periodontal biotypes. The first was a scan following standard methods; however, for the ST‐CBCT the patients wore a plastic lip retractor and retracted their tongues toward the floor of their mouths. With the first scan, only measurements of the distance of the cementoenamel junctional (CEJ) to the facial bone crest, and the width of the facial alveolar bone were possible. In contrast, ST‐CBCT allowed measurements of the distance of the gingival margin to the facial bone crest, the gingival margin to the CEJ, and width of the facial gingiva. ST‐CBCT scans allowed a clear visualization, measurement of the dimensions, and analysis of the relationship of the structures of the periodontium and dentogingival attachment apparatus.

CLINICAL SIGNIFICANCE

The dimensions and relationships of the structures of the dentogingival attachment apparatus are essential aspects in many fields of dentistry and this report describes a simple, novel, and noninvasive technique to determine them. This technique may aid clinicians in the planning and execution of procedures in several dental specialties.     

An anthropometric analysis of indices of severity in the unilateral cleft lip

The aim of this study was to analyze the relationships among three key anthropometric parameters in the unilateral cleft lip to determine the correlations, if any, among these indices of severity. Using a standardized anthropometric documentation protocol, preoperative measurements of 125 unilateral cleft lips (103 complete and 22 incomplete) were performed under general anesthesia by a single surgeon at the time of primary lip repair at the age of 3 months. The following key measurements were analyzed statistically: (1) the philtral height difference (PHD) between the cleft and noncleft sides, (2) the nasal floor width difference (NFWD) between the cleft and noncleft sides, and (3) the cleft width (CW). The mean values of all three indices were greater in the complete group versus the incomplete group. These differences were statistically significant. Linear relationships were obtained between NFWD and GAP, between PHD and GAP, and between PHD and NFWD in the complete group. In contrast, the relationships between PHD and GAP, and between PHD and NFWD were nonlinear in the incomplete group. These findings suggest that there was a strong correlation between the transverse and vertical tissue deficiencies in the complete cleft lip. In incomplete clefts, however, this correlation did not exist. In other words, the incomplete cleft lip can be associated with a severely short philtrum even in the presence of a relatively mild transverse tissue deficit. Therefore, it is not necessarily easier to repair an incomplete cleft lip in terms of the correction of the vertical tissue deficiency.     

Palate height: another indicator of surgical outcome in unilateral cleft lip and palate?

OBJECTIVE: To determine whether palate height and maxillary arch depth are systematically related to the surgical center at which primary repair in unilateral cleft lip and palate (UCLP) was carried out. DESIGN: A retrospective comparison based on study casts of consecutive cases of UCLP obtained at age 9 years from six different centers. The observer who conducted measurements was blinded to the source of individual records. SETTING: The patients whose records were analyzed received all their surgical care in a national health service setting in six different northern European centers and regions. PATIENTS: Patients were consecutively treated Caucasian children with non-syndromic complete UCLP born in the period 1976 to 1979. MAIN OUTCOME MEASURES: The main outcome measures for the original study were craniofacial form, dental arch relationships, nasolabial appearance, and speech. This report focuses on measurements of anterior maxillary arch depth and palate height. Results: Anterior arch depth and anterior palate height showed some variation among the centers. There was a tendency for anterior arch depth and palate height to also be reduced at centers at which patients showed unfavorable dental arch relationships. CONCLUSIONS: Anterior arch depth and palate height might be considered in future studies of surgical outcome and in their possible relationship to problems of articulation.     

Relationships between alveolar bone levels measured at surgery, estimated by transgingival probing and clinical attachment level measurements

Alveolar bone level measurements obtained by transgingival probing were compared with alveolar bone levels measured during surgery at 178 sites in 9 patients. Probing depth measurements using constant loads of 30 g and 60 g were also compared with bone levels measured at surgery at the above sites. The effects of inflammation, location of the site on the tooth surface and tooth type were also investigated. Transgingival probing was unaffected by these factors and proved to be an accurate method of measuring alveolar bone levels (r = 0.975). Probing depth measurements were affected by the presence of inflammation, assessed by the bleeding response to probing, and variation in probing load. The effect of inflammation was to reduce the mean distance between the probe tip and the alveolar bone from 2.4 mm to 1.9 mm. None of the relationships between the measurements were significantly affected by the location of the site on the tooth surface, or by tooth type.     

安氏Ⅱ类1分类错上下颌基骨前后关系诊断指标的可靠性评价

目的 评价反映安氏Ⅱ类1分类错上下颌基骨前后关系13项指标的可靠性。方法 安氏Ⅱ类1分类错患者120例，男60例，女60例，年龄20-28岁。拍摄自然头位（NHP）下的头颅定位侧位片。一金属链悬于头颅前方，其在胶片上的影像作为确定真性水平面（THP）的依据。X线头影测量项目包括ANB角、AB平面角、Wits值、AF-BF、AXB平面角、AB/SN4、AB/PP、AXD平面角、AD/SN、SGn/AB角、APDI角、FABA角、β角及A、B两点在THP上垂足间的距离（AB/HP）。计算各测量项目的相关系数；测量结果按最小相关系数指标分类法行聚类分析。所有测量结果用SPSS11.0统计软件进行分析。结果 相关分析表明各项指标除Wits值和SGn/AB角外多数呈高度相关性；聚类分析采用最小相关系数指标分类，结果按0.60水准分为5类。结论 在安氏Ⅱ类1分类错患者中，除Wits和SGn/AB外其他11项指标均可作为上下颌基骨前后关系的评价指标。AB/SN4能比较真实地反映上下颌骨的矢状关系；ANB角、AB平面角、β角、AF-BF、AXB平面角、FABA角、AB/PP、APDI角等指标具有相似的临床意义。     

安氏Ⅱ类1分类错(牙合)上下颌基骨前后关系诊断指标的可靠性评价

目的评价反映安氏Ⅱ类1分类错（牙合）上下颌基骨前后关系13项指标的可靠性。方法安氏Ⅱ类1分类错（牙合）患者120例,男60例,女60例,年龄20-28岁。拍摄自然头位（NHP）下的头颅定位侧位片。一金属链悬于头颅前方,其在胶片上的影像作为确定真性水平面（THP）的依据。X线头影测量项目包括ANB角、AB平面角、Wits值、AF—BF、AXB平面角、AB／SN4、AB／PP、AXD平面角、AD／SN、SGrdAB角、APDI角、FABA角、B角及A、B两点在THP上垂足间的距离（AB／HP）。计算各测量项目的相关系数：测量结果按最小相关系数指标分类法行聚类分析。所有测量结果用SPSS11．0统计软件进行分析。结果相关分析表明各项指标除Wits值和SGrdAB角外多数呈高度相关性：聚类分析采用最小相关系数指标分类,结果按0．60水准分为5类。结论在安氏Ⅱ类1分类错（牙合）患者中,除Wits和SG11／AB外其他11项指标均可作为上下颌基骨前后关系的评价指标。AB／SN。能比较真实地反映上下颌骨的矢状关系：ANB角、AB平面角、β角、AF—BF、AXB平面角、FABA角、AB／PP、APDI角等指标具有相似的临床意义。     

Characteristics of movement of the lips, tongue and velum during a bilabial plosive: a noninvasive study using a magnetic resonance imaging movie

OBJECTIVE: To obtain dynamic images of articulators using a magnetic resonance imaging (MRI) movie and to clarify the relationships among the articulators. MATERIALS AND METHODS: The subjects consisted of 10 volunteers. Custom-made circuitry was connected to an MRI apparatus to enable an external trigger pulse to control the timing of the scanning sequence and to provide an auditory cue for synchronization of the subject's utterance. The subject repeated a bilabial plosive, and the run was measured using a gradient echo sequence with a repetition time of 30 ms. Several variables were defined to delineate the individual movements of articulators and to determine the temporal relationships among them. RESULTS: It was found that (1) the change in these variables showed distinctive waveforms; (2) mean values of the standard deviations for these variables were relatively small; and (3) the movement of the velum was significantly correlated with those of the lips and the anterior part of the tongue, but not with the posterior part of the tongue. CONCLUSIONS: These results suggest that (1) articulatory movements were clearly recorded using an MRI movie, and (2) there seems to be a central mechanism for controlling articulators, and the level of coupling may be associated with the place of articulation.     

Dietary intake, food preferences, stimulated salivary flow rate, and masticatory ability in older adults with complete dentitions

This study was conducted to determine whether significant relationships exist among the masticatory ability, chewing-stimulated salivary flow rate, food preferences, and dietary intake of older adults with complete natural dentitions. Pearson r correlations revealed that significant relationships existed between: (1) salivary flow rate and eighteen out of the twenty-two nutrients comprising dietary intake; (2) masticatory ability and six out of the twenty-two nutrients comprising dietary intake; and (3) the perceived frequency of ingestion of the thirteen test foods and the dietary intake of thirteen of the nutrients comprising dietary intake. No significant relationships were found among salivary flow rate, masticatory ability, and food preferences. The amount of saliva accumulated in the mouth during the consumption of food may play an important role in food choices and subsequent intake of nutrients by older adults. Masticatory ability may not play as large a role as salivary flow rate in determining the selection and consumption of nutrient-rich foods.     

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目的研究不同耳点选择对头影测量值的影响并探讨其相关因素。方法选择2003年7月至2007年7月于中国医科大学口腔医学院正畸科就诊的青春发育高峰期后的105例患者头颅定位侧位片,分别采用机械耳点和解剖耳点定位眶耳平面,配对研究不同眶耳平面与下颌平面、上颌平面和面平面所成角度的差异,并分析不同错类型及不同性别之间机械耳点和解剖耳点的垂直距、水平距的差异。结果机械耳点和解剖耳点定位眶耳平面与下颌平面、上颌平面和面平面所成角度差异均有统计学意义,不同错类型及不同性别在机械耳点和解剖耳点的垂直距、水平距上差异无统计学意义。结论机械耳点和解剖耳点的位置存在明显差异,在头影测量分析中不能混用。     

Incisal changes and orthodontic stability.

Lateral cephalograms and study casts of 55 patients were evaluated to determine if any relationships exist among incisal positions and angulations, changes in positions and angulations, and long-term occlusal stability. No significant relationships could be found between long-term changes occurring in a number of commonly used incisal measurements and end-of-treatment incisal positions, changes in incisal positions during treatment, or long-term changes in the facial axis angle, ANB angle, or weighted PAR score. Long-term incisal changes occurring in individual patients were not necessarily associated with negative occlusal changes. Since incisal positions usually change in the long-term, it is suggested that the use of published norms or recommended absolute goals for end-of-treatment incisal positions be used more as general functional and esthetic clinical guides, rather than as predictors of stability.     

Craniofacial morphology: a principal component analysis.

A series of 56 measurements was derived from lateral cephalometric radiographs of a large sample of subjects. These measurements were subjected to a principal-component analysis which resulted in a series of six components (factors). These factors, represented in general terms and in rank order of their percentage sample variability were as follows: Factor 1. Vertical facial characteristics Factor 2. Anteroposterior aspects of facial morphology Factor 3. Midfacial and dental protrusion Factor 4. Relationship of the mandible and dentition to the profile Factor 5. Horizontal base-line relationships (internal or deep) Factor 6. Maxillary incisor relationships These principal components and the variables contained within them were shown to have sex and age interactions. A longitudinal study of the principal component changes with age was then undertaken. Demonstrable age changes were verified for Factors 1, 2, and 3, and Factors 1 and 3 were observed to show patterns of change which were statistically different from each other and the remaining principal components. An orthodontically treated sample of patients was also assessed for factor changes. Factors 1 and 2 were found to show statistically reliable changes resulting from treatment and/or growth. The remaining four factors showed no statistically supportable alteration. The data-reduction method involving a principal-component analysis would seem to have potential research and clinical applications.     

Malocclusion, masticatory muscle, and temporomandibular joint tenderness

The Angle classification of occlusion, as well as occlusal contacts determined at retrusion, mediotrusion, laterotrusion, and protrusion were recorded from 298 dental students. Various masticatory muscles and the TM joints were palpated simultaneously for tenderness. No significant relationships were observed between (1) tenderness and Angle class or (2) tenderness and any occlusal contact. In relation to a slide between retruded contact position and intercuspal position: measurements for (a) vertical and (b) horizontal displacements, but not (c) lateral deflection, were greater in Class I students without tenderness than in Class I students with tenderness.     

Validation of optical three-dimensional plagiocephalometry by computed tomography, direct measurement, and indirect measurements using thermoplastic bands

The aim of the study was to validate optical three-dimensional surface imaging for plagiocephalometry by comparing it with established direct and indirect plagiocephalometric measurements. From head models with symmetric and asymmetric shapes, a number of distances were determined for plagiocephalometry. Data were acquired by optical three-dimensional surface imaging, direct and indirect measurements, and computed tomography. Data acquisition was repeated 10 times with each method. In 10 patients with positional plagiocephaly, optical three-dimensional surface data were acquired, and thermoplastic strips were used to reproduce the largest circumferences of the patients' heads. All measurements were carried out by the same observer. The measurements for the head models were used to assess the reproducibility of the different measurement techniques and to check if there were statistically significant differences between them. The patient measurements were also used to determine if there were statistically significant differences between the different techniques in clinical use. None of the plagiocephalometric distances showed statistically significant differences when the 4 different methods were compared on the head models (P > 0.05). Comparison of plagiocephalometric distances obtained from optical three-dimensional imaging and from thermoplastic strips in clinical use showed also no significant difference (P > 0.05). The results of the current study reveal that optical three-dimensional imaging is a relevant alternative to other established techniques in plagiocephalometry that should be tested in larger patient series.     

Knowledge, attitudes, practices, and training needs of Kentucky dentists regarding violence against women

Dentists may be the first (and perhaps the only) health care professionals to treat patients who have experienced oral facial trauma resulting from domestic violence. Dentists are likely to see the signs of abuse while performing an oral examination and they often develop relationships with patients that could allow them to detect subtle changes in patients that may indicate signs of domestic violence. This study sought to assess the knowledge, attitudes, practices, and training needs of Kentucky dentists regarding domestic violence against women (VAW). A written survey was sent to a population of 1,892 eligible licensed dentists in Kentucky; 790 (42%) were returned. Ninety percent of the respondents were general dentists and the distribution by practice location was almost equal among urban, suburban, and rural dentists. Only 7.0% of respondents reported having any training in the prevention of VAW. When asked "... are you legally required to report suspected cases of VAW to the appropriate authorities, regardless of the patient's wishes?", 42% answered "no." An overwhelming majority (82%) indicated that they would like more training and information regarding VAW identification and management. Based on analysis of the data, Kentucky dentists would benefit from and be interested in additional education opportunities concerning recognizing, referring, and managing patients who may be the victim of domestic violence.