The reproducibility of natural head posture: a methodological study

Evaluation of the Cervical Vertebrae Maturation Index in Lateral Cephalograms Taken in Different Head Positions

The aim of this study was to evaluate if upward or downward head inclination might interfere with determination of the growth stage, using cervical vertebrae maturation index (CVMI), in order to verify the accuracy of such diagnosis when radiographs are taken with errors. Forty-nine patients, 26 females and 23 males, aged 9 to 15 years, were submitted to 3 lateral cephalograms: normal (NHP), with 15° upward head inclination (NHP-Up), and with 15° downward head inclination (NHP-Down). Three examiners evaluated the CVMI on the 147 cephalograms. The agreement among examiners was higher in the evaluation of cephalograms taken in NHP. The weighted Kappa test revealed moderate to substantial agreement between NHP and NHP-Up and between NHP and NHP-Down. There was greater agreement between NHP-Up and NHP-Down. It may be concluded that the evaluation of the CVMI on cephalograms in NHP is different as compared with radiographs taken with inclinations. Both NHP-Up and NHP-Down exhibited greater disagreement in the interpretation among examiners, since the evaluation method was not designed for cephalograms with positioning errors.

A cephalometric investigation of horizontal lip position in adult Nigerians

OBJECTIVES

The aims of this study were to (1) identify soft tissue cephalometric norms for horizontal lip position in an adult Nigerian population; (2) compare values for Nigerian males and females; and (3) compare Nigerian norms with established norms for Caucasians and other populations.

DESIGN

A cross-sectional descriptive study.

SETTING

Lagos University Teaching Hospital Dental Clinic, Idi-araba, Lagos, Nigeria.

PARTICIPANTS

One hundred students (44 males and 56 females) of the College of Medicine, University of Lagos, aged 18-25 years, of Nigerian ancestry, with a normal class I occlusion and no facial asymmetry.

METHODOLOGY

Lateral cephalometric radiographs of the subjects were taken in natural head position. Radiographs were manually traced and 11 soft tissue cephalometric parameters measured. These were derived from the Steiner, Ricketts, Burstone, Merrifield and Holdaway soft tissue analyses. Male and female values were compared using Student's t-test with a level of significance at P<0·05.

RESULTS

Statistically significant differences were observed between Nigerian males and females in eight of the variables studied, with males having more protrusive upper and lower lips than the females. Variables, which did not vary by sex, were soft tissue facial angle, nose prominence and soft tissue chin thickness. In addition, Nigerian norms were higher than norms reported by Steiner, Ricketts, Burstone and Holdaway for Caucasian populations, while the Z-angle was lower than the norm established by Merrifield.

CONCLUSIONS

Gender-specific soft tissue norms for horizontal lip position should be used for orthodontic treatment planning in Nigerian subjects. Nigerians have more protrusive upper and lower lips compared to Caucasians.

A determination of occlusal plane comparing different levels of the tragus to form ala-tragal line or Camper's line: A photographic study

PURPOSE

The purpose of this study was to determine accurately the part of the tragus to be used to form the Ala-Tragal line or Camper's line in orthognathic profile patients.

MATERIALS AND METHODS

150 dentate subjects with age of 18-40 years with orthognathic profile were sampled. Life-size lateral digital photographs of the face with fox plane were taken in natural head position. Different angles between Eye-Ear plane and occlusal plane (OT₁-OP), Eye-Ear plane and ala-superior border of tragus (OT₁-AT₁), Eye-Ear plane and ala-middle border of tragus (OT₁-AT₂) and Eye-Ear plane and ala-inferior border of tragus (OT₁-AT₃) were calculated using computer software package, AutoCAD 2004. From the three angles formed by the Eye-ear plane (OT₁ or FH plane) and the ala-tragal lines, the one closest to the angle formed between Eye-Ear plane (OT₁) and occlusal plane (OP) was used to determine the occlusal plane of orientation. The obtained results were subjected to ANOVA F test, Tukey's Honestly significant difference test, followed by Karl Pearson coefficient of correlation test. P values of less than 0.05 were taken as statistically significant.

RESULTS

The mean of base line angle i.e. OT₁-OP angle (11.96 ± 4.36) was found to be close to OT₁-AT₂ angle (13.67 ± 1.93) and OT₁-AT₃ angle (10.31 ± 2.03), but OT₁-OP angle was found to be more closer to OT₁-AT₃ angle. Comparison of mean angles showed that OT₁-OP angle in both males (11.68) and females (12.51) is close to OT₁-AT₃ angle (males- 11.01, females- 11.95).

CONCLUSION

The line joining from ala to the lower border of the tragus was parallel to the occlusal plane in 53.3% of the subjects. There was no influence of the sex on the level of occlusal plane.

Cervical musculoskeletal impairments and temporomandibular disorders

Objectives

The study of cervical muscles and their significance in the development and perpetuation of Temporomandibular Disorders has not been elucidated. Thus this project was designed to investigate the association between cervical musculoskeletal impairments and Temporomandibular Disorders.

Material and Methods

A sample of 154 subjects participated in this study. All subjects underwent a series of physical tests and electromyographic assessment (i.e. head and neck posture, maximal cervical muscle strength, cervical flexor and extensor muscles endurance, and cervical flexor muscle performance) to determine cervical musculoskeletal impairments.

Results

A strong relationship between neck disability and jaw disability was found (r = 0.82). Craniocervical posture was statistically different between patients with myogenous Temporomandibular Disorders (TMD) and healthy subjects. However, the difference was too small (3.3º) to be considered clinically relevant. Maximal cervical flexor muscle strength was not statistically or clinically different between patients with TMD and healthy subjects. No statistically significant differences were found in electromyographic activity of the sternocleidomastoid or the anterior scalene muscles in patients with TMD when compared to healthy subjects while executing the craniocervical flexion test (P = 0.07). However, clinically important effect sizes (0.42 - 0.82) were found. Subjects with TMD presented with reduced cervical flexor as well as extensor muscle endurance while performing the flexor and extensor muscle endurance tests when compared to healthy individuals.

Conclusions

Subjects with Temporomandibular Disorders presented with impairments of the cervical flexors and extensors muscles. These results could help guide clinicians in the assessment and prescription of more effective interventions for individuals with Temporomandibular Disorders.

Cephalometric evaluation of oropharyngeal airway dimension changes in pre- and postadenoidectomy cases

AIM

The aim is to compare and evaluate the airway dimension changes, adenoidal nasopharyngeal ratio (ANR), airway area and airway percentage in patients in pre- and postadenoidectomy with normal individuals.

MATERIALS AND METHODS

After obtaining informed consent, a sample of 15 patients (eight males and seven females) of 7 to 12 years were selected for adenoidectomy by an otolaryngologist, lateral cephalograms were taken in natural head position before adenoidectomy and after 1 month postadenoidectomy. Statastical analysis was done to evaluate the results using Statastical Package for Social Sciences. Results showed airway (P1, P2, P3, P4), airway percentage, airway area showed significant increase (p < 0.0001), whereas ANR showed significant reduction after 1 month postadenoidectomy.

CONCLUSION

One month postadenoidectomy showed increased airway area, airway percentage and reduced ANR.

CLINICAL SIGNIFICANCE

Obstructive mouth breathing due to adenoids in growing children can cause alteration in craniofacial morphology leading to adenoid facies, adenoidectomy procedure helps in alleviating the obstruction and facilitates the normal growth of craniofacial complex.

Over-bite and vertical changes following first premolar extraction in high angle cases

AIMS AND OBJECTIVES

Orthodontists generally agree that nonextraction treatment is associated with downward and backward rotation of the mandible and an increase in the lower anterior face height (LAFH). They also agree that extraction line of treatment is associated with upward and forward rotation of the mandible and decrease in the LAFH. The intent of this cephalometric investigation was to examine the wedge hypothesis, that the vertical dimension collapses after first bicuspid extraction. The present study was undertaken to evaluate the cephalometric overbite and vertical changes following first premolar extraction in high angle cases.

MATERIALS AND METHODS

Forty-five adult patients having high mandibular plane angle, i.e. Gogn--SN more than or equal to 32° having class I molar and canine relation were included. Pre and post-treatment lateral cephalograms were measured and compared to analyze the cephalometric changes.

RESULTS

There was no decrease in the overbite and vertical changes following first premolar extraction in high angle cases.

CLINICAL SIGNIFICANCE

The facial complex does increase in size with growth, but mandibular plane while moving inferiorly, remain essentially parallel to its pretreatment position due to residual growth and treatment mechanics.

CONCLUSION

The study concluded that, There was no decrease in the vertical facial dimension, overbite and mandibular plane angle. However, it should be interpreted with caution, given the small sample size.

Study of face pleasantness using facial analysis in standardized frontal photographs

OBJECTIVE: The purpose of this research was to check if the numeric facial analysis can determine facial attractiveness. METHOD: The sample consisted of frontal and lateral standard facial photographs, in natural head position, of 85 Brazilian Caucasian women, without facial plastic surgery report. The sample mean age was 23 years and 9 months. A group of 5 orthodontists, 5 layman and 5 plastic artists classified the photographs according to their own attractiveness graduation in: pleasant, acceptable and not pleasant. The numeric facial analysis was then performed using a computerized method. Linear, proportional and angular measurements were compared among groups. RESULTS: According subjective analysis the sample was consisted of 18.8% of pleasant, 70.6% of acceptable and 10.6% of not pleasant. In most measurements there were no differences among groups. Just in three of them significant statistical difference was observed and in two of them the comparison value was within decision limit. All the differences found were related to the lower third of the face and to facial pattern. CONCLUSION: On the present research, the numeric facial analysis, by itself, was not capable of detecting facial attractiveness, considering that beauty judgment seems to be very personal.

[Search of a cephalometric reference line]

The variability of cephalometric reference lines is examined in this article with regard to typology, natural orientation of the head, orientation by the vestibular system, and anatomy. It appears that these lines have orientations that vary with individual subjects, that is, a line is not the same in a specific person as it is in a theoretical model that is based on average values. It follows from this that the deviation observed between a patient's measurement and the average could just as well reflect variations in the reference lines as it does of those of the structures being studied. Such a measurement cannot, accordingly, serve as the basis for a morphological diagnosis. To deal with this problem, we propose another cephalometric reference system that presents, for orthognathic diagnosis, many advantages over the traditional system but, itself, remains imperfect.

Orthodontists' perceptions of the need for orthognathic surgery in patients with Class II Division 1 malocclusion based on extraoral examinations

INTRODUCTION

The purpose of this study was to establish the influence of soft-tissue profile values on the decision of orthodontists to recommend orthognathic surgery for patients with Class II Division 1 malocclusion.

METHODS

A questionnaire containing 40 profile photographs of adults with Class II Division 1 malocclusion was sent to all 256 consultant orthodontists in the United Kingdom asking for a "yes" or "no" response to the question: "Based on the profile view of this patient, would you treat this patient using an orthognathic surgical approach?" A soft-tissue analysis was carried out on each photograph, and multi-level logistic regression was used to investigate factors that affect the decision to recommend surgery.

RESULTS

The response rate was high: 208 of 256 questionnaires (81.3%). Intraexaminer reliability of the photographic analysis method with a Bland-Altman plot showed good (95% CI) limits of agreement for each measurement. Consultants who carried out more orthognathic surgery treatment were more likely to recommend surgery. Secondary analysis with a logistic regression model indicated that 80% of the consultants would recommend surgery if B-point was more than or equal to -14.1 mm posterior to the true vertical through subnasale (95% CI, -29.9 to -10.9 mm), the facial profile angle was less than or equal to 148.9° (95% CI, 6.7° to 151.1°), pogonion to true vertical through subnasale was more than or equal to -12.0 mm (95% CI, -48.7 to -8.6 mm).

CONCLUSIONS

The facial profile angle and the positions of soft-tissue pogonion and B-point are useful clinical guides for planning treatment for adults with Class II Division 1 malocclusion.

Creation of the virtual patient for the study of facial morphology

The author provides an overview of the new imaging technologies that allow the practitioner to accurately capture the patient's soft tissue facial morphology and underlying bones and teeth, including details of dental model integration. This article describes how a virtual patient is created and manipulated and the practical use of this technology. It takes the quantification of the 3D surface further by proposing a reference framework of landmarks of craniofacial structure that can be used for comparison of surgical change, growth, gender, and phenotype.

Digital live-tracking 3-dimensional minisensors for recording head orientation during image acquisition

INTRODUCTION

Our objective was to test the value of minisensors for recording unrestrained head position with 6 degrees of freedom during 3-dimensional stereophotogrammetry.

METHODS

Four 3-dimensional pictures (3dMD, Atlanta, Ga) were taken of 20 volunteers as follows: (1) in unrestrained head position, (2) a repeat of picture 1, (3) in unrestrained head position wearing a headset with 3-dimensional live tracking sensors (3-D Guidance trackSTAR; Ascension Technology, Burlington, Vt), and (4) a repeat of picture 3. The sensors were used to track the x, y, and z coordinates (pitch, roll, and yaw) of the head in space. The patients were seated in front of a mirror and asked to stand and take a walk between each acquisition. Eight landmarks were identified in each 3-dimensional picture (nasion, tip of nose, subnasale, right and left lip commissures, midpoints of upper and lower lip vermilions, soft-tissue B-point). The distances between correspondent landmarks were measured between pictures 1 and 2 and 3 and 4 with software. The Student t test was used to test differences between unrestrained head position with and without sensors.

RESULTS

Interlandmark distances for pictures 1 and 2 (head position without the sensors) and pictures 3 and 4 (head position with sensors) were consistent for all landmarks, indicating that roll, pitch, and yaw of the head are controlled independently of the sensors. However, interlandmark distances were on average 17.34 ± 0.32 mm between pictures 1 and 2. Between pictures 3 and 4, the distances averaged 6.17 ± 0.15 mm. All interlandmark distances were significantly different between the 2 methods (P <0.001).

CONCLUSIONS

The use of 3-dimensional live-tracking sensors aids the reproducibility of patient head positioning during repeated or follow-up acquisitions of 3-dimensional stereophotogrammetry. Even with sensors, differences in spatial head position between acquisitions still require additional registration procedures.

Comparison of reproducibility of natural head position using two methods

Lateral cephalometric radiographs have become virtually indispensable to orthodontists in the treatment of patients. They are important in orthodontic growth analysis, diagnosis, treatment planning, monitoring of therapy and evaluation of final treatment outcome.

AIM

The purpose of this study was to evaluate and compare the maximum reproducibility with minimum variation of natural head position using two methods, i.e. the mirror method and the fluid level device method.

MATERIALS AND METHODS

The study included two sets of 40 lateral cephalograms taken using two methods of obtaining natural head position: (1) The mirror method and (2) fluid level device method, with a time interval of 2 months. Inclusion criteria • Subjects were randomly selected aged between 18 to 26 years Exclusion criteria • History of orthodontic treatment • Any history of respiratory tract problem or chronic mouth breathing • Any congenital deformity • History of traumatically-induced deformity • History of myofacial pain syndrome • Any previous history of head and neck surgery.

RESULTS

The result showed that both the methods for obtaining natural head position-the mirror method and fluid level device method were comparable, but maximum reproducibility was more with the fluid level device as shown by the Dahlberg's coefficient and Bland-Altman plot. The minimum variance was seen with the fluid level device method as shown by Precision and Pearson correlation.

CONCLUSION

The mirror method and the fluid level device method used for obtaining natural head position were comparable without any significance, and the fluid level device method was more reproducible and showed less variance when compared to mirror method for obtaining natural head position.

CLINICAL SIGNIFICANCE

Fluid level device method was more reproducible and shows less variance when compared to mirror method for obtaining natural head position.

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.

Reliability of the integrated radiograph-photograph method to obtain natural head position in cephalometric diagnosis

OBJECTIVE

To introduce a simple and reliable method to reorient lateral radiographs to the natural head position (NHP) according to standardized photographs made at NHP.

MATERIAL AND METHODS

The study has two parts. In the first part, 45 patients were randomly selected from a patient cohort. Photographs (at NHP) and cephalograms from each patient were taken and assessed in two sessions by two observers. The time between the first and the second session was 5 weeks. The repeatability of profile measurements on cephalograms compared with standardized photographs of the same patient was determined; in the second part, the repeatability of three superimposing protocols (ie, the soft tissue N/subnasale line [V-line], the esthetic line [E-line], and a proposed nose best fit line [N-line]) was compared for the reorientation of the cephalogram according to the photographs made at the NHP.

RESULTS

Our results showed that the integration of radiographs and photographs is an objective and reliable method to obtain NHP in lateral cephalograms. The N-line is a reproducible and stable reference line for the reorientation of radiographs to obtain NHP.

CONCLUSION

Reorientation of radiographs according to standardized photographs made at the NHP is a reliable and objective method to standardize the radiographs at the NHP for cephalometric analysis. The N-line is a reproducible and stable reference line for the reorientation. It is preferred over the V-line or even E-line, especially when the radiographs and photographs are taken at different sessions or at different treatment stages.

An evaluation of nasolabial angle and the relative inclinations of the nose and upper lip

Esthetics is one of the major motivating factors for patients seeking orthodontic treatment. Hard tissue and soft tissue drape both determine the facial esthetics. The structures in this region are so variable that the nasolabial angle (NLA) has been drawn differently by various investigators. Variations can lead to erroneous conclusions in orthodontic diagnosis.

AIMS AND OBJECTIVES

The study was done to evaluate a reliable method of constructing the nasolabial angle (NLA) and to correlate the soft tissue profile parameters with one another.

MATERIALS AND METHODS

Lateral cephalogram of 50 randomly selected adult patients were taken. The tracings were made and 10 copies of each tracing were randomly distributed to 10 different orthodontists to draw the NLA.

RESULTS

Pearson's correlation coefficient (r) showed both N/ FH and L/FH angles to have significant p values when compared with NLA. The regression analysis showed that the nasolabial angle can be calculated for any given value of N/FH or L/FH by the formula: NLA = 80.33° + 1.02° (N/FH) and NLA = 14.2° + 1.04° (L/FH). The mean value of N/FH was 17.42° ± 8.40° and L/FH was 80.68° + 6.45° for this sample. Inter examiner reliability calculated by repeated measures of ANOVA and Dahlerg's formula showed high degree of reliability and reproducibility of the method.

CLINICAL SIGNIFICANCE

NLA can be predicted for any given value of N/FH and L/FH. NLA = 80.33° + 1.02° (N/FH) and NLA = 14.2° + 1.04° (L/FH). If an individual has either N/FH or L/FH in the normal range but not the NLA then one could calculate the correct NLA using this formula. Thereby the NLA can be brought within the normal range by altering the other nasolabial parameters by correct treatment planning. Since the nasolabial angle plays a vital role in profile esthetics of a person, the clinician should place greater emphasis in evaluating this area and plan treatment mechanics to place this angle within the accepted normal variation.

Effect of awareness through movement on the head posture of bruxist children

The aim of this study was to evaluate the effectiveness of physiotherapy to improve the head posture and reduce the signs of bruxism in a group of bruxist children. A single-blind randomized clinical trial was performed. All the subjects were 3- to 6-year old, had complete primary dentition, dental and skeletal class I occlusion and were classified as bruxist according to the minimal criteria of the ICSD for bruxism. For each child, a clinical, photographic and radiographic evaluation of the head and cervical posture were realized with standardized techniques. The children were randomized in an experimental (n = 13) and a control (n = 13) group. A physiotherapeutic intervention was applied to the children of the experimental group once a week, until 10 sessions were completed. Afterwards, the cephalogram and the clinical and photographic evaluation of the head posture were measured again. The data were analysed with the t-test and Mann-Whitney test. The subjects of the experimental group showed statistically significant improvement in the natural head posture. The physiotherapeutic intervention showed to be efficient to improve the head posture at the moment of measurement in the studied children. The relationship between bruxism and head posture, if exists, seems to be worthwhile to examine.

Influence of isolated cleft palate and palatoplasty on the face

Introduction

The literature has demonstrated that alterations in craniofacial morphology characterizing individuals with cleft palate are observed in both operated and unoperated patients.

Objective

This study evaluated the influence of isolated cleft palate and palatoplasty on the face, based on facial analysis.

Material and methods

Lateral facial photographs of the right side of 85 young adult patients with cleft palate were analyzed, of whom 50 were operated on and 35 had never received any previous surgical treatment. The nasolabial angle and zygomatic projection were used to define the maxillary position in the face. Mandibular positioning was classified as Pattern I, II and III.

Results

Patients were distributed into 54.12% as Pattern I, 32.94% Pattern II and 12.94% Pattern III. Distribution of facial patterns did not show statistically significant differences between groups (p>0.05). Although palatoplasty did not influence the facial pattern, the zygomatic projection was vulnerable to plastic surgeries. Twenty-eight percent of the patients in the operated group showed zygomatic deficiency, compared to only 8.5% in the unoperated group.

Conclusions

In patients with isolated cleft palate, palatoplasty may influence negatively the sagittal behavior of the maxilla, according to the zygomatic projection of the face, though without compromising the facial pattern.

Head orientation in CBCT-generated cephalograms

OBJECTIVE

To determine the reliability of obtaining two-dimensional cephalometric measurements using two virtual head orientations from cone-beam computed tomography (CBCT) models.

MATERIALS AND METHODS

CBCT scans of 12 patients (6 class II and 6 class III) were randomly selected from a pool of 159 patients. An orthodontist, a dental radiologist, and a third-year dental student independently oriented CBCT three-dimensional (3D) renderings in either visual natural head position (simulated NHP) or 3D intracranial reference planes (3D IRP). Each observer created and digitized four CBCT-generated lateral cephalograms per patient, two using simulated NHP and two using 3D IRP at intervals of at least 3 days. Mixed-effects analysis of variance was used to calculate intraclass correlation coefficients (ICCs) and to test the difference between the orientations for each measure.

RESULTS

ICC indicated good reliability both within each head orientation and between orientations. Of the 50 measurements, the reliability coefficients were > or =0.9 for 45 measurements obtained with 3D IRP orientation and 36 measurements with simulated NHP. The difference in mean values of the two orientations exceeded 2 mm or 2 degrees for 14 (28%) of the measurements.

CONCLUSIONS

The reliability of both virtual head orientations was acceptable, although the percentage of measurements with ICC >0.9 was greater for 3D IRP. This may reflect the ease of using the guide planes to position the head in the 3D IRP during the simulation process.

The relationship of facial anatomic landmarks with midlines of the face and mouth

STATEMENT OF PROBLEM

The importance of the midline is well known to dentists. Currently, there are no verifiable guidelines that direct the choice of specific anatomic landmarks to determine the midline of the face or midline of the mouth.

PURPOSE

The purpose of this study was to determine the hierarchy of facial anatomic landmarks closest to the midline of the face as well as midline of the mouth.

MATERIAL AND METHODS

Three commonly used anatomic landmarks, nasion, tip of the nose, and tip of the philtrum, were marked clinically on 249 subjects (age range: 21-45 years). Frontal full-face digital images of the subjects in smile were then made under standardized conditions. A total of 107 subjects met the inclusion criteria. Upon applying exclusion criteria, images of 87 subjects were used for midline analysis using a novel concept called the Esthetic Frame. Deviations from the midlines of the face and mouth were measured for the 3 clinical landmarks; the existing dental midline was considered as the fourth landmark. The entire process of midline analysis was done by a single observer and repeated twice. Reliability analysis and 1-sample t tests were conducted at alpha values of .001 and .05, respectively.

RESULTS

The results indicated that each of the 4 landmarks deviated uniquely and significantly (P<.001) from the midlines of the face as well as the mouth.

CONCLUSIONS

Within the limitations of the study, the hierarchy of anatomic landmarks closest to the midline of the face in smile was as follows: the midline of the oral commissures, natural dental midline, tip of philtrum, nasion, and tip of the nose. The hierarchy of anatomic landmarks closest to the midline of the oral commissures was: natural dental midline, tip of philtrum, tip of the nose, and nasion. These relationships were the same for both genders and all ethnicities classified.

Surgical-orthodontic treatment of Class III patients with long face problems: a retrospective study

PURPOSE

To describe the surgical procedure in correcting Class III patients with long face problems and to evaluate the lateral cephalometric changes resulting from surgical-orthodontic treatment.

PATIENTS AND METHODS

Thirty-six Chinese Class III patients with long face problems (14 male, 22 female, with a mean age 24.3 years) were selected in this study. All patients underwent bimaxillary surgery. The surgical approach involved advancement and superior repositioning (greater anteriorly than posteriorly) of the maxilla to permit autorotation and subsequent setback of the mandible. Lateral cephalometric records were taken before the presurgical orthodontic treatment (T1) and after the postsurgical orthodontic treatment (T2). The data were analyzed statistically by using paired t tests.

RESULTS

Anteroposterior and vertical dysplasia were corrected by the surgery. Horizontalization of the occlusal plane was obtained and the gonial angle was closed. The S-Go/N-Me increased 2% (P < .01), whereas ANS-Me/N-Me displayed no significant difference.

CONCLUSIONS

The surgical procedure makes it possible to obtain an optimal esthetic and functional result in cases of Class III long face patients. This approach represents a useful option for the treatment of these deformities.

Angular photogrammetric analysis of the soft tissue facial profile of Anatolian Turkish adults

The purpose of this study was to establish norms of photogrammetric soft tissue profile analysis for Anatolian Turkish adults. Standardized right lateral facial photographs of 111 Anatolian Turks (64 females, 47 males) with class I skeletal pattern were taken. Age range was 21 to 40 years. Descriptive statistics for 8 angular measurements were computed. Male and female values were compared with Mann-Whitney U test. Intraclass correlation coefficients (ICCs) were calculated for repeated measurements. Intraobserver reliability of the photogrammetric measurements was quite high with 6 measurements having ICCs above 95% and the other 2 measurements having ICCs of 77% and 87%. Sexual dimorphism was found for 4 measurements: Nasofacial (G-Pog/N-Prn: P < 0.001) and middle facial height (N-Trg_Sn: P < 0.05) angles were higher in men, whereas nasal (N-Prn-Sn: P < 0.01) and nasolabial (Cm-Sn-Ls: P < 0.05) angles were higher in women. Nasofrontal (G-N-Prn), nasal (N-Prn-Sn), and nasolabial (Cm-Sn-Ls) angles revealed large individual variations.

Angular photogrammetric analysis of the soft tissue facial profile of Turkish adults

One of the most important components of orthodontic diagnosis and treatment planning is the evaluation of the patient's soft tissue profile. The aim of this study was to develop angular photogrammetric standards for Class I Anatolian Turkish males and females. A random sample of 100 Turkish individuals (46 males and 54 females; ages 19-25 years) was obtained. The photographic set-up consisted of a tripod that held a 35 mm camera and a primary flash. The camera was used in its manual position and photographic records were taken of the subjects in natural head posture. The photographic records, 35 mm slide format, were digitized and analyzed using the Quick Ceph Image software program for Windows. Twelve measurements were digitally analyzed on each photograph. For statistical evaluation a Student's t-test was performed and the reliability of the method was analyzed. The results were compared with reported norms of facial aesthetics. The nasofrontal (G-N-Prn), nasal (Cm-Sn/N-Prn), vertical nasal (N-Prn/TV), and nasal dorsum (N-Mn-Prn) angles showed statistically insignificant gender differences (P>0.05). The nasolabial angle (Cm-Sn-Ls) demonstrated large variability. Gender differences were present in the mentolabial (Li-Sm-Pg) and cervicomental (G-Pg/C-Me) angles. The mentolabial angle showed a high method error and large variability. Facial (G-Sn-Pg) and total facial (G-Prn-Pg) convexity angles were similar, while Cm-Sn-Ls angle range was larger compared with other angles. The mean values obtained from this sample can be used for comparison with records of subjects with the same characteristics and following the same photogrammetric technique. Angular photogrammetric profile analysis can provide the orthodontist with a way of determining problems associated with various soft tissue segments of the face.

An evaluation of head position and craniofacial reference line variation

Natural head position (NHP) is the usual, balanced position of the head which is adopted for viewing the horizon or an object at eye level. Determination of NHP is useful when reconstructing facial form in art, forensics, orthodontic diagnosis and treatment planning for surgical management of craniofacial dysmorphic conditions. When NHP is uncertain, correction such as orientation to Frankfurt horizontal (FH) has been advocated. However, FH angulation varies between individuals and is subject to landmark identification error. Previous studies have measured FH and other craniofacial planes in relation to the true horizontal (HOR) with subjects in NHP and have found similar variation to that found with FH. This study measured craniofacial planes in 40 Aboriginal Australians (20 male, 20 female, aged 17 years or greater) from lateral cephalographs and compared its results with classical previous studies. Four planes, the neutral horizontal axis (NHA), FH, Krogman-Walker line (KW line), and palatal plane (P plane) demonstrated near parallelism and averaged between -1 degrees and -2 degrees from HOR. The combined use of NHA, FH, KW line, and P plane enables more effective corrected head position (CHP).

Head posture and dental wear evaluation of bruxist children with primary teeth

The aim of the present study was to compare the head position and dental wear of bruxist and non-bruxist children with primary dentition.

METHODS

All the subjects had complete primary dentition, dental and skeletal class I occlusion and were classified as bruxist or non-bruxist according to their anxiety level, bruxism described by their parents and signs of temporomandibular disorders. The dental wear was drawn in dental casts and processed in digital format. Physiotherapeutic evaluation and a cephalometric radiograph with natural head position were also performed for each child to evaluate the cranio-cervical position for the bruxist group (n = 33) and the control group (n = 20). The variables of the two groups were compared, using the Student t-test and Mann-Whitney U-test.

RESULTS

A more anterior and downward head tilt was found in the bruxist group, with statistically significant differences compared with the controls. More significant dental wear was observed in the bruxist children.

CONCLUSIONS

Bruxism seems to be related to altered natural head posture and more intense dental wear. Further studies are necessary to explore bruxism mechanisms.

Relationship of TMJ osteoarthritis / osteoarthrosis to head posture and dentofacial morphology

OBJECTIVE

The purpose of this study was to test the hypothesis that there is a relationship between the temporomandibular joint (TMJ) osteoarthritis/osteoarthrosis (OA), head posture and dentofacial morphology.

DESIGN

Case-control study.

SUBJECTS AND METHODS

The subjects consisted of 34 Japanese females with TMJ OA (aged 24.7 +/- 6.1 years) and a control group of 25 healthy Japanese females (aged 23.6 +/- 1.3 years). Six cranio-cervical angular measurements were constructed for head posture analysis. Nine angular and three linear measurements were constructed for the skeletal hard tissue analysis. Five angular and one linear measurements were constructed for the dental hard tissue analysis. Unpaired t-tests were used to compare the mean differences of head posture measurements and dentofacial cephalometric measurements between the TMJ OA and the control group.

RESULTS

The TMJ OA group had significantly larger cranio-cervical angles (p < 0.05) and had more posteriorly rotated mandibles (p < 0.0001) than those in the control group. They also had a significantly shorter posterior facial height (p < 0.0001). The TMJ OA group had more retroclined lower incisors (p < 0.05).

CONCLUSION

These results suggest that an association may exist between TMJ OA, head posture and dentofacial morphology.

The Relationship Between Estimated and Registered Natural Head Position

Objective: To study the inherent relationship between registered and estimated natural head position and further explore the nature of natural head position.

Materials and Methods: Thirty-one pretreated patients were included in this study. Both registered natural head position (RNHP) and estimated natural head position (ENHP) were obtained. For RNHP, mirror orientation was used to help to adjust the subject's head position. For ENHP, two approved standard photographs were studied by the assessors before estimation. Correlation analysis was used to analyze the relationship between two angles: Rphoto/Rxray and Ephoto/ Eray.

Results: A significant correlation was found between RNHP and ENHP, both on the photographs and on the cephalograms.

Conclusion: There is a strong correlation between RNHP and ENHP. RNHP is the subjective perception of the subject and gets some objective meaning by mirror orientation. ENHP is the subjective perception of assessors and gets objective meaning by a standardization session in advance. The mirror orientation of RNHP and the advance standard study of ENHP are crucial for validity and accuracy of NHP as an extracranial reference plane.

Proportional Analysis of Longitudinal Craniofacial Growth Using Modified Mesh Diagrams

Objective: To study the craniofacial changes of adolescents followed longitudinally with their heads oriented in natural head position.

Materials and Methods: Longitudinal cephalograms of adolescents (n = 28) with normal occlusion, selected from among 900 candidates, were taken at 13 and again at 18 years of age. Modified elaborate mesh diagrams were developed defined by 90 anatomic landmarks and an additional 172 interpolated points for each cephalogram using a preset computer program. Detailed proportional and disproportional craniofacial changes were showed by both statistical and graphical methods.

Results: In females, most craniofacial regions exhibited growth that was proportionate to the mesh core rectangle reference on extracranial true vertical. In males, there was an upward, disproportional enhanced shift of the anterior cranial base and a downward enhanced shift of the mandibular symphysis and inferior border of the corpus.

Conclusions: This elaborate mesh analysis, based on mesh core rectangle and referenced on estimated natural head position, provides a novel graphical as well as quantitative method of assessing craniofacial growth. From 13 to 18 years of age, two sexes with normal occlusion displayed different growth patterns referenced on estimated natural head position. In females, most craniofacial regions exhibited growth proportional to the mesh core rectangle. In males, there was an upward, enhanced shift of the anterior cranial base and a downward enhanced shift of the mandibular symphysis and inferior border of the corpus.

Digital videographic measurement of tooth display and lip position in smiling and speech: Reliability and clinical application

INTRODUCTION

Tooth display and lip position in smiling and speech are important esthetic aspects in orthodontics and dentofacial surgery. The spontaneous smile and speech are considered valuable diagnostic criteria in addition to the posed social smile. A method was developed to measure tooth display in both smile types and speech.

METHODS

The faces of 20 subjects were individually filmed. Spontaneous smiles were elicited by a comical movie. The dynamics of the spontaneous smile were captured twice with a digital video camera, transferred to a computer, and analyzed on videoframe level. Two raters were involved. Posed social smiles and speech records were also included. Reliability was established by means of the generalizability theory. It incorporated rater, replication, and selection facets.

RESULTS

Generalizability coefficients ranged from .99 for anterior teeth to .80 for posterior teeth. The main sources of error were associated with rater and selection facets. The replication facet was a minor source of error.

CONCLUSIONS

This videographic method is reliable for measurement of tooth display and lip position in spontaneous and posed smiling and speaking. Application of the method is warranted especially when obtaining an emotional smile is difficult, such as cleft lip and palate or disfigured patients.

Estética em Ortodontia: Diagramas de Referências Estéticas Dentárias (DRED) e Faciais (DREF)

Seria interessante que todas as especialidades odontológicas envolvidas com a Odontologia Estética utilizassem parâmetros estéticos dentários e faciais que fossem comuns a todos os profissionais. Considerando que essa tarefa só poderá ser exercida quando as especialidades puderem contar com análises estéticas simplificadas que sejam do entendimento de todos, esse trabalho propõe-se a apresentar os Diagramas de Referências Estéticas Dentárias e Faciais, que terão o intuito de prover uma avaliação da estética dentofacial, de uma forma simples, individualizada e subjetiva de cada paciente, e que servem como instrumentos de referência para todas as especialidades odontológicas, auxiliando no diagnóstico e planejamento dos tratamentos multidisciplinares.

Electromyographic assessment of the activity of the masticatory using the agonist contract–antagonist relax technique (AC) and contract–relax technique (CR)

Proprioceptive neuromuscular facilitation (PNF) techniques are a group of therapeutic procedures that may be used to cause relaxation of muscles. Studies have found controversial results when applying these techniques. The aim of the present study was to evaluate the effectiveness of masticatory muscle relaxation through the use of the contract-relax technique (CR) when compared with the agonist contract-antagonist relax technique (AC). A convenience sample of 30 students was recruited for this study. The CR and the AC techniques were applied to the subjects in order to cause relaxation of the masticatory muscles. Electromyography activity of all muscles was registered. Two way ANOVA with repeated measures analysis demonstrated that both the AC technique and the CR technique did not decrease the EMG activity of masticatory muscles (P>0.05). Instead, both techniques caused an increase in electromyographic activity of the masticatory muscles. Based on the results obtained from this study, both the CR and the AC techniques were not effective in causing relaxation of the masticatory muscles. The purported physiological mechanisms of PNF techniques, which stated that they act through reciprocal inhibition and autogenic inhibition causing muscular relaxation, are not supported by this study.

A comparison of the head and cervical posture between the self-balanced position and the Frankfurt method

Head and cervical posture evaluation has been a concern for many years, not only because of the purported relationship that exists between head and cervical posture in the presence of temporomandibular disorders, neck pain and headache, but also because of the biomechanical relationship between the head and cervical spine and dentofacial structures. Many methods have been suggested in an attempt to establish the best way to evaluate the position of the head using teleradiographs and cephalometric analysis. However, there is still no agreement as to which procedure is the best. The objective of this study was to evaluate the differences that exist between craniocervical measurements in lateral teleradiographs when comparing the position of the head in the self-balanced position to the position of the head using the Frankfurt method (Frankfurt plane parallel to the floor). Sixty-eight subjects who sought dental treatment in community health centres in Talca, Chile participated in this study. Rocabado analysis was used to measure the craniocervical variables. The Cobb analysis was used to measure cervical lordosis. A paired student t-test was used to evaluate the differences between both procedures, using an alpha of 0.05 and a power of 0.90. The use of the cephalostat changed only the craniocervical angle (P < 0.001). However, this change was minimal. No changes related to gender and age were found. More studies are needed to determine the variation between different procedures and to define a good procedure for evaluating head posture.

Relationship between head posture and hyoid position in adult females and males

AIM

The aim of this study was to investigate head posture and hyoid bone position using cephalometric radiographs of adults.

MATERIAL AND METHODS

The material consisted of 76 cephalometric films (38 each male/female) taken at the natural head posture. The individuals were over 18 years of age, had parents of Turkish origin, an acceptable face structure, ideal dental occlusion, and an ANB angle of 1-5 degrees; the dentitions were complete except the third molars and there were no visual, hearing, breathing or swallowing disorders. In addition, the subjects had not undergone orthodontic treatment or orthognathic surgery, had no burns, injuries, or scars in the head and neck regions. In order to determine the natural head position, the subjects were asked to stand in a relaxed manner (the self-balance position), and this position was transferred to the cephalostat by means of a fluid level device. The differences among sexes were investigated by means of Student's t-test, carried out using SPSS (Windows 7.5).

RESULTS

It was found that there were no sex variations in head position. The linear measurements regarding the position of hyoid bone showed statistically significant differences with respect to sex. However, hyoid bone position was higher and more posterior in females, while natural head position was not affected by sex.

Changes in natural head position observed immediately and one year after rapid maxillary expansion

Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A number of studies have examined the relationship between RME and the change in airway resistance, or the relationship between airway resistance and natural head position (NHP). Few studies, to date, have examined the relationship between RME and the change in NHP resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni- or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion, and one year after RME. No significant changes in the craniofacial angles were observed immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14 degrees (P < 0.01), OPT/HOR by 2.13 degrees (P < 0.05), and CVT/HOR by 2.55 degrees (P < 0.05). The results of this study suggest an ongoing change in head posture possibly due to a change in the mode of breathing from oral to nasal as a result of RME, thereby contributing to a change in craniofacial development, supporting and adding to the soft tissue stretching hypothesis.

Determinants of successful treatment of bimaxillary protrusion: orthodontic treatment versus anterior segmental osteotomy

The purpose of this study was to investigate the differences in initial skeletal, dental, and soft tissue characteristics of bimaxillary protrusion (BP) patients to determine poor or good results with orthodontic treatment (OT) or anterior segmental osteotomy (ASO) with extraction of four first premolars. Lateral cephalometric radiographs of 46 adult Korean females with BP were analyzed before treatment (T0) and after treatment (T1). According to the measurements at T1, patients were classified into group 1 (poor result with OT, n = 12), group 2 (good result with OT, n = 11), group 3 (poor result with ASO, n = 5), and group 4 (good result with ASO, n = 18). Sagittal, vertical, dental, and soft tissue variables were measured. The differences at T0 among the four groups were compared by one way analysis of variance test and verified by Scheffe's multiple comparison test. Stepwise discriminant analysis was performed to find decisive predictors. Skeletal class II malocclusion tendency, less developed chin, and vertical facial growth pattern were related with group 1. Overly uprighted and less protrusive upper and lower incisor, near normal interincisal angle (IIA), less protrusive upper lip, and more obtuse lower nasolabial angle (NLA) were related with group 3. IIA, U1-NA distance, combination factor, interlabial gap, lower NLA, pterygomaxillary fissure-N, and posterior nasal spine-anterior nasal spine were selected as significant variables for discriminating the four groups. The percentage of correctly classified cases was 91.3%. In particular, the discriminant function showed the highest accuracy in the prediction of group 4. These variables and discriminant functions contributed to the differential diagnosis on BP to make a procedural decision between OT and ASO.

A New Rig for Standardized Craniofacial Photography Put to the Test

This article describes and tests a photography rig that has been built at the University of Melbourne, Australia, specifically for the purpose of taking rapid and highly standardized craniofacial photographs, in simultaneous views of front and profile. The rig uses a novel projected light range-finding system that has been designed for easy and accurate positioning of subjects, in the natural head position, at precise distances from the frontal camera. Results of experiments examining the intraobserver error of multiple photographs taken on the rig indicate that high-quality, repeatable photographs can be taken after a reasonably large amount of time has lapsed between photography sessions (e.g., 30 days). This study also indicates that some variability remains between photographs even when highly standardized protocols are followed. Consequently, it is expected that the variation between photographs with limited standardization is much larger and more likely to cause significant errors in any comparisons.

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.

Reproducibility of natural head position measured with an inclinometer

Sagittal (pitch) and transversal (roll) natural head position (NHP) was measured once in 20 subjects, 18 to 24 years of age, with an inclinometer; the measurements were repeated 2 years later. The method error (reproducibility) after 2 years was 1.1 degrees for sagittal and transversal measurements. The mean change in NHP measurement was -0.3 degrees for both measurements, and the variance was 1.21 degrees (= 1.1(2)).

Increasing the cervical lordosis with chiropractic biophysics seated combined extension-compression and transverse load cervical traction with cervical manipulation: nonrandomized clinical control trial

BACKGROUND

Cervical lordosis has been shown to be an important outcome of care; however, few conservative methods of rehabilitating sagittal cervical alignment have been reported.

OBJECTIVE

To study whether a seated, retracted, extended, and compressed position would cause tension in the anterior cervical ligament, anterior disk, and muscle structures, and thereby restore cervical lordosis or increase the curvature in patients with loss of the cervical lordosis.

STUDY DESIGN

Nonrandomized, prospective, clinical control trial.

METHODS

Thirty preselected patients, after diagnostic screening for tolerance to cervical extension with compression, were treated for the first 3 weeks of care using cervical manipulation and a new type of cervical extension-compression traction (vertical weight applied to the subject's forehead in the sitting position with a transverse load at the area of kyphosis). Pretreatment and posttreatment Visual Analogue Scale (VAS) pain ratings were compared along with pretreatment and posttreatment lateral cervical radiographs analyzed with the posterior tangent method for changes in alignment. Results are compared to a control group of 33 subjects receiving no treatment and matched for age, sex, weight, height, and pain.

RESULTS

Control subjects reported no change in VAS pain ratings and had no statistical significant change in segmental or global cervical alignment on comparative lateral cervical radiographs (difference in all angle mean values < 1.3 degrees ) repeated an average of 8.5 months later. For the traction group, VAS ratings were 4.1 pretreatment and 1.1 posttreatment. On comparative lateral cervical radiographs repeated after an average of 38 visits over 14.6 weeks, 10 angles and 2 distances showed statistically significant improvements, including anterior head weight bearing (mean improvement of 11 mm), Cobb angle at C2-C7 (mean improvement of -13.6 degrees ), and the angle of intersection of the posterior tangents at C2-C7 (mean improvement of 17.9 degrees ). Twenty-one (70%) of the treatment group subjects were followed for an additional 14 months; improvements in cervical lordosis and anterior weight bearing were maintained.

CONCLUSIONS

Chiropractic biophysics (CBP) technique's extension-compression 2-way cervical traction combined with spinal manipulation decreased chronic neck pain intensity and improved cervical lordosis in 38 visits over 14.6 weeks, as indicated by increases in segmental and global cervical alignment. Anterior head weight-bearing was reduced by 11 mm; Cobb angles averaged an increase of 13 degrees to 14 degrees; and the angle of intersection of posterior tangents on C2 and C7 averaged 17.9 degrees of improvement.