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Results for “Cephalometry”

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PubMed1987

Biparietal diameter growth in uncomplicated twin gestation.

Ninety-six fetuses of uncomplicated concordant twin pregnancies were monitored by ultrasonic cephalometry from 13 to 38 weeks gestation. The biparietal diameter (BPD) growth of 96 twin fetuses was then compared to a sample of 299 uncomplicated, appropriate-for-gestational-age singleton pregnancies. Regression analysis applied to these measurements of BPD on twin and singleton pregnancies showed no significant difference in biparietal diameter between uncomplicated singleton and twin pregnancies. It is concluded that charts derived from singleton pregnancies may be reliably used for estimation of gestational age of twins.

Cephalometry↗

PubMed2003

The effect of anabolic steroids on mandibular growth.

The aim of this study was to assess the effect of nandrolone (Deca-Durabolin, AKZO Nobel, Cambridge, United Kingdom) on mandibular growth in juvenile and adult rats with radiographic cephalometry and immunoradiology. Juvenile (n = 16) and adult (n = 16) inbred female Wistar-Kyoto rats were compared. Each group was divided into 2 subgroups with 8 experimental (E) and 8 control (C) animals in each subgroup. Lateral headfilms taken before and after the 70-day study period were analyzed. Body weight and blood serum IGF-I levels were monitored weekly. The results showed marked mandibular growth changes in both the juvenile and the adult E rats. Body weight increase was larger in the E than in the C animals. The IGF-I blood serum levels were similar in the juvenile E and C rats but higher in the adult E animals than in the adult C animals. It was found that the anabolic steroid (Deca-Durabolin) had a significant effect on mandibular growth in both juvenile and adult rats.

Age Factors↗

PubMed2003

Long-term effect of pharyngeal flap surgery on craniofacial and nasopharyngeal morphology in patients with cleft palate.

The craniofacial morphology of 48 consecutive adult males with isolated cleft palate was studied by means of lateral cephalograms at the mean age of 18.8 years. Twelve of the patients had received pharyngeal flap surgery between 4 and 12 years of age (mean age 6 years) to improve speech. No significant differences were noticed in craniofacial cephalometric relations between the patients who had not had velopharyngeal flap surgery (VPF-) and those who had (VPF+), although the latter showed a tendency toward a more vertical growth direction. In the pharynx, the VPF+ group showed larger sagittal depths of nasopharyngeal airway but smaller depths of oropharyngeal airway. The differences were significant at the levels of the upper nasopharynx and lower oropharynx. According to the hospital records, none of the patients demonstrated persistent airway obstruction. Cephalometry may be useful in evaluating the changes in pharyngeal airway dimensions that may be related to velopharyngeal flap surgery.

Adolescent↗

PubMed2002

Cephalometric and fiberoptic evaluation as a case-selection technique for obstructive sleep apnea syndrome (OSAS).

In order to obtain relatively simple and useful parameters to estimate the severity of obstructive sleep apnea syndrome (OSAS), cephalometric and fiberoptic studies were performed in 64 clinical cases previously diagnosed with either OSAS or snoring. Fourteen cephalometric parameters, 13 parameters derived from physical examination and 18 fiberoptic parameters were compared with the apnea index (AI), the apnea-hypopnea index and lowest SaO2 values. Statistically significant correlations were found between the Al and the shortest linear distance from the posterior line of the soft palate to the posterior pharyngeal wall measured along a line parallel to the supramentale-Gonion line (PAS-epipharynx distance), the distance from the mandibular plane to the most anterior and superior point on the body of the hyoid bone obtained from cephalometry (MP-H distance) and the degree of redundancy of mucosa in the arytenoid/aryepiglottic fold obtained from videoendoscopy. An increased Al was observed when the PAS-epipharynx distance was < 7 mm and there was 100% obstruction in Muller's maneuver at the palate level (supine), the MP-H distance was > 27.4 mm and the mucosa of the arytenoid/aryepiglottic fold was markedly redundant. As these three parameters are relatively easy to obtain on an outpatient basis, it is suggested that they could be used in an outpatient setting to provide a good prediction of the severity of OSAS.

Adult↗

PubMed2001

Adult skeletal profile in isolated cleft palate: a comparison of the von Langenbeck and Wardill procedures for primary repair of the palate.

Sixty-four adult patients operated on for isolated cleft palate were evaluated with regard to facial skeletal morphology using conventional radio-cephalometry. Dental occlusion was assessed clinically. Forty-two had had a von Langenbeck repair at the age of 7 months and 22 a Wardill repair at 18 months. The mean error of the method was 0.7 degree for angular, and 0.9 mm for linear, measurements. The group with clefts had less maxillary prognathism (s-n-ss), more maxillary inclination (NSL/NL), more retroclined lower incisors (ILI/ML), and shorter total and upper facial heights (n-gn, n-sp) compared with the reference group. Multiple regression analysis was used to evaluate differences between the two treatment regimens. Explanatory variables in addition to surgical technique were sex, severity of cleft, and presence of a velopharyngeal flap. Only one variable, lower incisor inclination (ILI/ML), was different for the two regimens. Ten (24%) in the von Langenbeck group had a lateral cross-bite compared with one (5%) in the Wardill group. Other variables in a multivariate regression analysis were affected by sex and severity of cleft to various degrees. This study showed no obvious differences in facial skeletal morphology that could be attributed to surgical technique. Factors other than technique, including sex, age, and severity of cleft merit attention.

Adult↗

PubMed1999

Comparisons of facial growth in patients with unilateral cleft lip and palate treated by different regimens for two-stage palatal repair.

The aim of this study was to compare facial development, particularly growth of the maxilla, of two groups of patients with unilateral cleft lip and palate in whom palatal surgery had been done slightly differently, particularly the timing of the procedures. Two-stage palatal repair had been used at 8 (velar closure) and 102 months (hard palate surgery) at one cleft centre and at 20 and 62 months at another centre. Lateral roentgencephalograms were used to analyse the first sample of 20 patients, who were followed longitudinally from 7-16 years of age. The other group comprised 17 subjects in the same age range, who were investigated cross-sectionally, also by cephalometry. Generally, the outcome of the two surgical regimens was similar and equally satisfactory, with no evident difference in facial or maxillary morphology between the two samples. From the midfacial growth point of view, it might be questioned whether it is necessary to delay closure of the cleft in the hard palate until the mixed dentition stage as was done at the first cleft centre.

Adolescent↗

PubMed1998

Interrelationships of brain, cranial base and mandible.

The purpose of this study is to evaluate the neural and masticatory growth factors that contribute to the development of the cranial base. Cephalometric and submentovertex (SMV) radiographs of 66 adult human skulls, of Caucasian (India) origin and unknown gender were used in this study. Results indicate that the cranial base, posterior to the foramen caecum, develops in response to brain growth. The part anterior to the foramen caecum develops in response to the mandible. Our findings indicate that: 1. the glabella instead of the nasion should be considered as the most anterior point of the cranial base. Mandibular dimensions (the height and the length) have a better correlation with CG than CN. 2. Instead of a single parameter, sella-nasion (SN), two parameters, the foramen caecum-glabella (CG) and the foramen caecum-sella (CS) should be considered. In cephalometry the more stable line CS, rather than SN, can be used for registration of successive radiographs; 3. The typical mandibular retrognathia, and/or the decrease in the posterior height (ascending ramus) of a Class II malocclusion could be explained by their positive correlation with SB (sella-basion) and the negative correlation with angle GSB.

Adult↗

PubMed1998

Relationship between difficult tracheal intubation and obstructive sleep apnoea.

The upper airway abnormalities predisposing to difficult tracheal intubation may also predispose to obstructive sleep apnoea (OSA). The potential association is important as both conditions increase perioperative risk and patients with a trachea that is difficult to intubate may need assessment for OSA. We determined if patients with difficult intubation are at greater risk of OSA and, if so, whether or not they have characteristic clinical or radiographic upper airway changes. We studied 15 patients in whom the trachea was difficult to intubate and 15 control patients. Each was evaluated clinically (Mallampati score, thyromental distance, neck circumference, head extension), polysomnographically (apnoea-hypoponea index (AHI)) and radiographically (lateral cephalometry). AHI was greater in the difficult intubation group (mean 28.4 (SD 31.7)) compared with controls (5.9 (8.9)) (P < 0.02); eight of 15 patients in the difficult intubation group and two of 15 in the control group had an AHI > 10 (P < 0.03). Difficult intubation, but not OSA, was associated (P < 0.05) with a smaller thyromental distance and mandibular length, and greater soft palate length. Both difficult intubation and OSA were associated (P < 0.05) with a greater Mallampati score, anterior mandibular depth, and smaller mandibular and cervical angles. OSA, but not difficult intubation, was associated (P < 0.05) with increased neck circumference, tongue area and craniocervical angle, and decreased head extension, mandibular ramus length and atlantooccipital distance. We conclude that difficult intubation and OSA are related significantly. They share anatomical features which act to reduce the skeletal confines of the tongue. Patients with OSA may compensate, when awake, by increasing craniocervical angulation, which increases the space between the mandible and cervical spine and elongates the tongue and soft tissues of the neck.

Adult↗

PubMed1992

The effect of treatment of skeletal open bite with two types of bite-blocks.

The treatment of anterior skeletal open bite was studied in two groups of children. The children of one group wore a removable spring-loaded bite-block in the lower jaw for one year. The bite-block exerted an intrusive force on the upper and lower posterior teeth. The children of the other group were treated for 3 months with bite-blocks with repelling magnets. These bite-blocks were cemented on the posterior teeth of both jaws. The effects of treatment were monitored by measurement of the bite-force (group with spring bite-blocks only), by electromyographic recording of the activity of the temporal and masseter muscles, and by X-ray cephalometry. Recordings were made before, during, and at the end of the treatment, and at a follow-up observation. The bite-force increased during the first months of treatment, but was then unchanged. The activity of the masseter muscle during maximal bite also increased in the first part of the period of treatment with a spring bite-block. In the group treated with magnetic bite-blocks, there was an increase in the resting activity of the masseter muscle and in the chewing activity of the anterior temporal muscle. The effects of the treatment on bite and facial morphology were less marked in the group with spring bite-blocks than in the group with magnetic bite-blocks, with an average improvement of the overbite of 1.3 mm with the spring bite-block therapy. In the group with magnetic bite-blocks, the average improvement in overbite was 3 mm. This was thought to be due to anterior rotation of the mandible and increased eruption of the incisors. The mandibular rotation was a result of intrusion of the upper and lower posterior teeth and possibly also increased mandibular growth. A follow-up of the cases treated with magnetic bite-blocks revealed a tendency for the beneficial effects of the treatment to relapse which possibly could be counteracted by a long phase of active retention.

Bite Force↗

PubMed1993

Craniofacial patterning in Klinefelter (47 XXY) adults.

Radiographic cephalometry incorporating a pattern profile analysis was used to compare 26 adult Klinefelter males from Finland with first degree adult relatives, 15 males and 14 females. Compared with female relatives, the 47 XXY males were larger in almost all craniofacial linear dimensions, but were similar in facial shape apart from greater mandibular prognathism. Mandibular dimensions in particular differed between the Klinefelter and unaffected males, the corpus length being larger, the ramus shorter and the gonial angle more obtuse in the 47 XXY group. The prominent facial profile, most marked in the mandible, was a dominant feature of the Klinefelter subjects who also displayed a more acute median cranial base angle than each control group. Generally, Klinefelter morphology was marked by greater variability or patterning of the craniofacial structures compared with relatives, possibly due to decreased developmental canalization. It is proposed that the 47 XXY complex may affect endochondral growth in the cranial base, as well as having a direct influence on jaw growth.

Adolescent↗

PubMed1993

A comparative assessment of cephalometric errors.

Measuring a cephalometric radiograph is an imprecise task, and the errors associated with this should be quantified and understood. The potential sources of error are outlined and the literature relating to the assessment of measurement errors is reviewed. Three techniques are examined: the error attributable to a single recording; its associated confidence limits; and the coefficient of reliability were the most commonly applied. Data from two error studies were pooled and used to compare the accuracy of 12 skeletal, dental, and soft tissue measurements, using various assessments of each of the three techniques. Within each group, the use of different mathematical criteria led to variation in the results; one method was totally unsuitable. As with all statistical procedures, a knowledge of the technique facilitates interpretation of the results. Some suggestions as to the most satisfactory approach to the estimation of measurement error in cephalometry are given.

Cephalometry↗

PubMed1995

Tensor analysis of facial growth in males.

This longitudinal study examines in detail the facial development of 18 untreated, male children with acceptable occlusions. The children were examined in the prepubertal period (age range 7-10 years) and again in their late teens (15-19 years of age). A tensor analysis, which permits the computation of differences in form (that is in size and shape) without specifically measuring either, was employed to describe the facial changes which occurred during this time interval. Values for the x and y co-ordinates of 16 hard and four soft tissue landmarks were determined at each stage. Customized software allowed both graphical and numerical examination of the mean changes over time between 28 triads of points, covering skeletal, dental, and soft tissue elements. The analysis confirmed previous work in describing facial change but was more sensitive than conventional cephalometry, especially where landmarks were evaluated outside the traditional sella-nasion framework.

Adolescent↗

PubMed1996

The use of tensor analysis to investigate facial changes in treated class II division 1 malocclusions.

This retrospective cephalometric study examined the facial changes brought about by treatment in 62 Class II division 1 children, using tensor analysis. Thirty-two children were treated with Fränkel appliances, whilst the remaining thirty received premolar extractions, headgear, and conventional Edgewise mechanics. Each child was matched for age and sex with an untreated individual in whom the occlusion was deemed satisfactory and the treatment changes were compared with those expected during normal development. Results indicated that vertical facial development predominated in both treated groups: this exceeded the increase expected in an untreated population . The Fränkel group exhibited the greater gain in lower face height, with changes confined almost entirely to the mandible. Effective mandibular position improved but there was no increase in body length. The incisors were more favourably positioned within the face with similar improvements in the soft tissues. Thus, although facial balance was better following a non-extraction Fränkel approach, control of the vertical dimension was inadequate. The fixed appliance group exhibited a smaller increase in lower facial height and no favourable mandibular development: maxillary retraction was the most striking skeletal alteration. By removing the traditional, fixed, superimpositional framework of the cranial base, tensor analysis highlights vertical and mandibular changes not easily detected by conventional cephalometry.

Adolescent↗

PubMed1998

Maxillofacial morphology and masseter muscle thickness in adults.

The aim of this study was to investigate how the thickness of the masseter muscle relates to the maxillofacial morphology, including the thickness of alveolar process in the mandibular incisor region, and the thickness of the mandibular symphysis. The subjects consisted of 80 adult male volunteers (mean age: 23 years 8 months). The relationship between masseter muscle thickness and the maxillofacial skeleton was investigated by measuring the former by ultrasonography and the latter by roentgenographic cephalometry. The data were initially analysed using a multiple regression analysis. Thereafter, correlation coefficients were obtained by a simple regression analysis. The following results were found: 1. The thickness of the masseter muscle (mean +/- SD) was 15.8 +/- 3.0 mm in the relaxed state and 16.7 +/- 2.7 mm at maximal clenching. 2. Masseter muscle thickness was negatively correlated with the mandibular plane angle. 3. Masseter muscle thickness was positively correlated with the mandibular ramus height (Cd-Go), and the thickness of the alveolar process and that of the mandibular symphysis. It is therefore suggested that masticatory function influences the morphology of the mandible.

Adult↗

PubMed2000

Statistical methods for the comparison of measurements derived from orthodontic imaging.

Biometric comparison procedures for dental imaging methods with continuous outcome were reviewed, mainly concentrating on assessment and comparison of accuracy and precision according to the study design. Univariate graphical and numerical representations of corresponding deviations were summarized to derive a 'check list' of minimum information necessary to compare the measurement methods. The methods reviewed in this investigation are illustrated by the comparison of conventional (radiographic) cephalometry versus assessment using the DigiGraph in 50 female children. A paired t-test and the corresponding confidence interval approach were used to assess deviations in location of two imaging methods; the test procedures of Maloney/Rastogi, Hahn/Nelson, and Grubbs were surveyed as proposals for the comparison of precisions in paired data. The Krippendorff coefficient was used as an aggregate measure for method concordance. Since these methods can be performed by simple modification of standard options available in most statistical software packages, this review intends to enable dental researchers to choose the correct methods, and perform adequate data analysis and representation.

Algorithms↗

PubMed2001

A prospective optical surface scanning and cephalometric assessment of the effect of functional appliances on the soft tissues.

The aim of this study was to evaluate the effect of different functional appliances on the soft tissues as assessed by cephalometry and optical surface scanning. Forty-two patients were randomly allocated to Bass, Twin Block (TB), and Twin Block + Headgear (TB + Hg) groups. Lateral cephalograms and optical surface scans were recorded before and after the 10-month study period. ANOVA was used to test the cephalometric variables for differences at the 5 per cent level. The optical surface scanning and cephalometric results were consistent in the sagittal dimension. In the vertical dimension, however, the optical surface scans consistently recorded a greater increase compared with cephalometric values. No differences were detected with regard to cephalometric values at the 5 per cent level. However, the Bass appliance produced greater forward positioning of soft tissue pogonion as assessed by optical surface scanning.

Analysis of Variance↗

PubMed2001

The clinical significance of error measurement in the interpretation of treatment results.

The aims of this investigation were to determine the errors involved in cephalometric landmark identification and to link these to the interpretation of treatment results. Fifty cephalograms were randomly selected from patient files and the following were determined. (i) Accuracy of the digitizer--single tracing digitized on five occasions on each of 10 different positions on the digitizer by one observer. (ii) Intra- and inter-observer digitizing error--35 landmarks on the same tracing (on a fixed position) digitized on five occasions by each of four judges. (iii) Intra- and inter-observer tracing error--five separate tracings of 10 different cephalograms by four judges. There were no significant differences in the variances of the co-ordinates for each landmark between the different positions on the digitizer (mean variance x-axis 0.07 mm and y-axis 0.08 mm). (ii) One-way ANOVA showed no significant intra- or inter-observer differences in digitation. (iii) Levene's test for homogeneity of variance showed significant differences in the co-ordinates of different landmarks and between the same landmarks on different cephalograms. Two-way ANOVA showed significant differences between observers for the same landmark that were greater than the intra-observer differences. The results indicate that tracing accuracy is a limiting factor in cephalometry. The variance of each landmark is dependent on the quality of the cephalogram. Inter-observer differences were greater than intra-observer effects and these were random, rather than systematic errors. Minimal error estimation calculations enable discrimination between treatment results and measurement errors.

Algorithms↗

PubMed2005

Guest editorial: what do prospective randomized clinical trials tell us about the treatment of class II malocclusions? A personal viewpoint.

The prospective randomized clinical trial (RCT) is seen by many to be the 'gold standard' for analysing treatment outcome and the only valid source of clinical data. In orthodontics, most RCTs have been designed to resolve the controversy surrounding the ability of functional appliances to significantly modify dentofacial growth. Given the variability in the timing, magnitude and duration of pubertal dentofacial growth, differing levels of motivation and patient compliance, the inherent inaccuracy of cephalometry and the questionable validity of the measurements themselves used to quantitate change, it is not surprising that the conclusions have not been as clear-cut as anticipated. Unlike a laboratory experiment, in which it is possible to limit the differences between experimental and control groups to the single factor being investigated, in a clinical trial an orthodontic appliance is just one of several variables affecting the outcome. Furthermore, RCTs are expensive and time-consuming; by the time the end-point of the study has been reached, the appliance may no longer be in widespread use, the fate of more than one recent well-publicized RCT. What RCTs have shown is that functional appliances such as the Herbst and twin block, based on the principle of 'jumping the bite', are more effective at modifying dentofacial growth and reducing overjets than headgear and more passive appliances such as the Andresen activator and its variants. However, if one asks whether RCTs have achieved their objective, or provided knowledge not previously available from retrospective studies or animal experimentation, then the answer would have to be no; it is also hard to justify the cost. What is particularly interesting is that knowledge based on years of clinical experience has been disregarded and then announced as if it was something completely new.

Cephalometry↗