Association between third molar agenesis and craniofacial structure development.

INTRODUCTION: The aim of this investigation was to study the relationship between third molar agenesis-including the number of ageneses-and craniofacial structure growth. METHODS: We reviewed 305 clinical histories of patients treated at the Orthodontics Unit of the Faculty of Medicine and Dentistry at the University of Valencia in Spain. This included radiographic records of optimal quality. Of these, 40 patients who had agenesis of at least 1 third molar were included in the study group. A control group was formed with another 40 patients with all 4 third molars present. For both groups, a further criterion for inclusion was cone-beam computed tomography records. The cephalometric analysis was performed with NemoCeph 3D software (version 11.3.1.38; Nemotec, Madrid, Spain). RESULTS: The only significant differences between the 2 groups were in the total gonial angle and the upper gonial angle (P ≤0.05), both of which were smaller in the study group. CONCLUSIONS: Third molar agenesis is associated with a reduction in Jarabak's gonial angle and upper gonial angle, characteristic of patients with a more horizontal or brachyfacial skeletal pattern. No significant differences were found in other measurements.

Comparison of craniofacial growth of untreated Class I and Class II girls from ages 9 to 18 years: a longitudinal study.

INTRODUCTION: The purposes of this study were to examine and compare the craniofacial growth in girls with Class I or Class II occlusion from the ages of 9 to 18. METHODS: Twenty-five Class I (ANB, 1°-4°) and 21 Class II (ANB, >4°) untreated Caucasian girls were selected from the Burlington Growth Centre in Toronto, Ontario, Canada. Cephalograms of each subject at ages 9, 14, and 18 years were traced, and 29 parameters were measured. The growth changes in each parameter from ages 9 to 14, 14 to 18, and 9 to 18 were calculated, and comparisons of each parameter were made between the 2 groups. RESULTS: From ages 9 to 14, the Class I and Class II groups had similar skeletal growth patterns (increases of SNA and SNB angles, decreases of ANB, MP-SN, and gonial angles). Dentally, the Class II group showed less maxillary incisal proclination and more overbite than did the Class I group. From ages 14 to 18, the 2 groups also showed similar growth patterns, with little sagittal but continued vertical growth, and the MP-SN angle continued to decrease. From ages 9 to 18 (combined periods of 9-14 and 14-18), the 2 groups showed similar skeletal growth, with the exception of a slightly higher ANS-ME/N-Me in the Class I group. Dental changes were similar in the 2 groups, except that overbite increased slightly more in the Class II group. CONCLUSIONS: Overall, the craniofacial growth patterns of Class I and Class II girls were similar. With growth, the face became more flattened with a decrease of the ANB angle, and the mandible demonstrated forward rotation with decreases of the MP-SN and gonial angles, and an increase of PFH:AFH.

Late adult skeletofacial growth after adolescent Herbst therapy: a 32-year longitudinal follow-up study.

INTRODUCTION: The aim of this longitudinal 32-year follow-up investigation was to analyze the very long-term effects of Herbst treatment on the dentoskeletal structures. We followed 14 patients from a sample of 22 with Class II Division 1 malocclusions who were consecutively treated with the banded Herbst appliance at ages 12 to 14 years. The subjects were reexamined after therapy at the ages of 20 years (when the radius epiphysis/diaphysis plate was closed) and 46 years. METHODS: Lateral head films were analyzed from before (T1) and after (T2) treatment, and at 6 years (T3) and 32 years (T4) after treatment. RESULTS: (1) In the standard analysis (angular measurements) during the T2 to T3 period of 6 years, significant skeletal changes were the following: increase of the SNB (1.0°; P <0.01), decrease of the ANB (0.9°; P <0.01), and decrease of the ML/NSL (2.5°; P <0.001). During the T3 to T4 period of 24 years, no further significant angular changes occurred. (2) In the analysis of the sagittal changes in the occlusion (linear measurements) during the T2 to T3 period of 6 years, the mandible (6.1 mm; P <0.001) and the maxilla (3.0 mm; P <0.01) grew forward. During the T3 to T4 period of 24 years, the mandible (2.8 mm; P <0.01) and the maxilla (3.1 mm; P <0.01) continued to grow forward. Thus, during the total posttreatment (T2-T4) period of 32 years, there was continuous forward growth of the mandible (8.9 mm; P <0.001) and the maxilla (6.1 mm; P <0.001). (3) The analysis of superimposed lateral head films showed in all 14 subjects large amounts of sagittal and vertical skeletofacial growth during T3 to T4. CONCLUSIONS: In all 14 subjects, large amounts of sagittal and vertical skeletofacial growth occurred after the age of 20 years. However, the question of when, during the period from 20 to 46 years, growth had come to an end remains open. Closure of the radius epiphysis/diaphysis plate is not useful as an indicator for completed skeletofacial growth. Our findings indicate the importance of considering late adult skeletofacial growth in dentofacial orthopedics, orthognathic surgery, and tooth implantology with respect to treatment timing, posttreatment retention, and relapse.

Cervical vertebrae maturation, dentoalveolar, head postural and respiratory parameters in predicting the stable outcome of face-mask treatment.

BACKGROUND/OBJECTIVES: To select predictors related to cervical vertebrae maturation (CVM), dentoalveolar adaptation, head posture, and respiration on outcome of face-mask treatment. MATERIALS/METHODS: Forty-six patients (24 boys and 22 girls) with skeletal Class III pattern whose CVM stages ranged from I to IV at pretreatment were selected. The observation period was 2.87 ± 1.77 years from the end of treatment. Negative overjet and overbite was regarded as unstable. CVM, 10 skeletal variables, 6 dental adaptation variables, 4 alveolar housing variables, an airway variable, and 2 head posture variables were chosen for discriminant analysis of initial characteristics between stable and unstable groups. RESULTS: Measurements exhibiting strong correlations were distance from lower incisor to Nasion, B point (NB), Frankfort horizontal plane to Mandibular incisor Angle (FMIA), incisor overbite, body to anterior cranial base. LIMITATIONS: We missed muscle-related variables, which cannot be identified in a cephalogram. CONCLUSIONS/IMPLICATIONS: Presence of non-skeletal cephalometric factors more closely associated with stability of face-mask treatment rather than skeletal cephalometric factors at the initial stage are confirmed.

Anterior cranial-base time-related changes: A systematic review.

INTRODUCTION: The anterior cranial base has long been considered a stable reference structure for superimposing radiographs. However, some studies have questioned its stability. Therefore, the purposes of this systematic review were to give an overview of the studies evaluating growth and development of the anterior cranial base, assess their methodologic quality, and evaluate their validity and accuracy. METHODS: Medline, Embase, and Google Scholar were searched without limitations up to June 2013. Additionally, the bibliographies of the finally selected articles were hand searched to identify any relevant publications that were not identified before. The lowest levels of evidence accepted for inclusion were cohort and cross-sectional studies. RESULTS: A total of 11 articles met all inclusion criteria. They were published between 1955 and 2009. The sample sizes of these studies ranged from 28 to 464 subjects. Their methodologic quality ranged from moderate to low. CONCLUSIONS: Sella turcica remodels backward and downward, and nasion moves forward because of the increase in size of the frontal sinus. These events lead to a continuous increase in the length of the cranial base until adulthood. The presphenoid and cribriform plate regions can be considered stable after age 7, making them the best cranial-base superimposition areas.

Do long-faced subjects really have a long anterior face? A longitudinal study.

INTRODUCTION: The aims of this study were to investigate and compare the anterior facial heights of children with long, normal, and short faces during growth and to discover whether long-faced subjects have long dimensions in both the upper and lower anterior facial heights compared with the others. METHODS: Longitudinal lateral cephalometric data of 167 children (83 girls, 84 boys) from 6 to 14 years of age were used. Total anterior face height, upper anterior face height, lower anterior face height, and the closest distance from the Frankfort horizontal plane to nasion were measured. The samples were classified as long-faced, normal-faced, and short-faced according to the ratio of lower to total face heights at 14 years old. All data were analyzed statistically and compared between the groups according to age. RESULTS: The mean lower anterior face height in the long-faced group was larger than in the normal-faced and short-faced groups for all ages in both sexes. In contrast, subjects in the normal-faced group had a longer mean upper anterior face height than did subjects in the long-faced and short-faced groups. In addition, the mean upper anterior face height of the short-faced group was larger than the long-faced group for girls at all ages and for boys at 12 to 14 years. CONCLUSIONS: The long-faced children did not have longer upper facial heights compared with normal-faced and short-faced children, and their long faces were mainly determined by the length of the lower face.

Tonsillotomy versus tonsillectomy--a randomized trial regarding dentofacial morphology and post-operative growth in children with tonsillar hypertrophy.

OBJECTIVES: The primary aim of this study was to analyse two different methods of tonsil surgery, tonsillectomy (TE) and tonsillotomy (TT), regarding post-operative dentofacial growth in children with tonsillar hypertrophy. A secondary aim was to analyse these results in relation to cephalometric standards. MATERIAL AND METHODS: The study group consisted of 64 subjects (39 boys and 25 girls), mean age 4.8 years ± 4 months. They were randomized to a complete removal of the pharyngeal tonsil, TE, (n = 31) or a partial removal, TT, (n = 33). Pre-operative and 2 years post-operative study material were obtained and analysed. The results were compared with cephalometric standards. RESULTS: Pre-operative, children with hypertrophic tonsils displayed an increased vertical relation (P < 0.05) compared with cephalometric standards. Post-operative, no significant difference could be detected between the two surgical procedures regarding dentofacial growth. Mandibular growth with an anterior inclination was significant (P < 0.001/TE, P < 0.01/TT) for both groups. An increased upper and lower incisor inclination was noted (P < 0.01/TE,TT). The vertical relation decreased (P < 0.001/TE, P < 0.05/TT) as well as the mandibular angle (P < 0.01/TE, P < 0.001/TT). Reduction was also significant for the sagittal intermaxillar (P < 0.001/TE,TT) relation. These post-operative results, together with a more prognatic mandible (P < 0.05/TE,TT) and chin (P < 0.001/TE, P < 0.01/TT), might indicate a more horizontal direction of mandibular growth. CONCLUSION: TE and TT yielded equal post-operative dentofacial growth in children treated for hypertrophic tonsils. This result should be considered when deciding upon surgical technique.

The inadequacy of the Y-axis of growth (SNGn) for the vertical pattern assessment in patients with sagittal discrepancies.

AIM: The aim of this cephalometric study was to evaluate the influence of the sagittal skeletal pattern on the 'Y-axis of growth' measurement in patients with different malocclusions. MATERIALS AND METHODS: Lateral head films from 59 patients (mean age 16y 7m, ranging from 11 to 25 years) were selected after a subjective analysis of 1630 cases. Sample was grouped as follows: Group 1 - class I facial pattern; group 2 - class II facial pattern; and Group 3 - class III facial pattern. Two angular measurements, SNGoGn and SNGn, were taken in order to determine skeletal vertical facial pattern. A logistic regression with errors distributed according to a binomial distribution was used to test the influence of the sagittal relationship (Class I, II, III facial patterns) on vertical diagnostic measurement congruence (SNGoGn and SNGn). RESULTS: RESULTS show that the probability of congruence between the patterns SNGn and SNGoGn was relatively high (70%) for group 1, but for groups II (46%) and III (37%) this congruence was relatively low. CONCLUSION: The use of SNGn appears to be inappropriate to determine the vertical facial skeletal pattern of patients, due to Gn point shifting throughout sagittal discrepancies. Clinical Significance: Facial pattern determined by SNGn must be considered carefully, especially when severe sagittal discrepancies are present.

Ontogenetic changes of craniofacial complex in Turner syndrome patients treated with growth hormone.

OBJECTIVE: The present study assessed changes of craniofacial complex in Turner syndrome (TS) patients treated with growth hormone (GH) during development. The objective was to examine the growth rate and pattern of craniofacial structures and to establish effects of GH on craniofacial development. MATERIALS AND METHODS: The study population consisted of 15 TS patients treated with GH aged 5-18.5 years (13.3 ± 4.4) and corresponding control group of 45 females aged 6.8-18.7 (11.4 ± 2.6). According to the stage of cervical vertebral maturation, subjects were categorized into pre-growth (5 TS and 15 controls) and growth (10 TS and 30 controls) subgroups. The cephalometric analysis comprised angular and linear variables, measured on lateral cephalometric radiographs. RESULTS: The mandibular corpus/anterior cranial base ratio increased significantly only in controls during development. In growth period, ramus/corpus ratio was significantly larger in TS group. SNA and SNB angles were significantly smaller in TS growth subgroup compared to corresponding controls. Among other variables, no statistically significant differences were revealed. CONCLUSIONS: In TS patients treated with GH, growth capacities of cranial base and maxilla are adequate which can be attributed to GH treatment. Shape of mandible is altered due to decreased growth of corpus and overdeveloped ramus. Both maxillary and mandibular retrognathism are becoming more expressed during development. CLINICAL RELEVANCE: Favorable influence of GH on craniofacial complex growth rate and altered growth pattern revealed in this study should be considered while planning both orthodontic treatment and retention.

Alteration of maxillary and mandibular growth of adult patients with unoperated isolated cleft palate.

OBJECTIVE: The objective of this study was to investigate the effects of cleft palate itself on the growth of maxilla and mandible. PATIENTS AND METHODS: Fifty-two adult female patients with unoperated isolated cleft palate and 52 adult female individuals with normal occlusion were included in our study. Computer software was used for lateral cephalometry measurement. Manual measurement was performed for dental cast measurements, and sample t test analysis was applied to analyze the differences between the 2 groups using SPSS 17.0. RESULTS: The sella-nasion-subspinale point angle, subspinale-nasion-supramentale point angle, and maxillary arch length of the cleft group were significantly smaller than those of the control group (P < 0.01). Both maxillary and mandibular posterior dental arch widths of the cleft group were significantly larger compared with the control group (P < 0.01), whereas the sella-nasion-supramentale point angle, mandible arch length, palate height, and palate shelf inclination did not differ between the 2 groups. The measurements did not differ between the submucosal cleft and the overt cleft patients. CONCLUSIONS: Cleft palate itself has adverse effects on the maxilla growth with shorter maxillary arch length and wider posterior dental arch width.

Real-time monitoring of the growth of the nasal septal cartilage and the nasofrontal suture.

INTRODUCTION: The nasal septum is thought to be a primary growth cartilage for the midface and, as such, has been implicated in syndromes involving midfacial hypoplasia. However, this internal structure is difficult to study directly. The aims of this study were to provide direct, continuous measurements of the growth of the nasal septal cartilage and to compare these with similar measurements of the nasofrontal suture to test whether the growth of the cartilage precedes the growth of the suture and whether the growth of the septal cartilage is constant or episodic. METHODS: Ten Hanford minipigs were used. Linear displacement transducers were implanted surgically in the septal cartilage and across the nasofrontal suture. Length measurements of the cartilage and suture were recorded telemetrically each minute for several days. RESULTS: The growth rate of the nasal septal cartilage (0.07% ± 0.03% length/h) was significantly higher than that of the suture (0.03% ± 0.02% length/h) (P = 0.004). The growth of both structures was episodic with alternating periods of growth (5-6 per day) and periods of stasis or shrinkage. No diurnal variation in growth of the cartilage was detected. CONCLUSIONS: These results are consistent with the notion that growth of the septal cartilage might drive growth of the nasofrontal suture. Growth of the midface is episodic rather than constant.

Patterns of vertical facial growth in Korean adolescents analyzed with mixed-effects regression analysis.

INTRODUCTION: To understand the growth patterns of skeletal open bite and deepbite, we present observations from 9 years of pure longitudinal data based on lateral cephalometric radiographs using mixed-effects regression model analysis. METHODS: In total, 51 children (14 years old) with extreme values for the ratio of lower anterior facial height to total anterior facial height were assigned to 1 of 2 groups: a skeletal open-bite group (11 boys, 14 girls) or a skeletal deepbite group (14 boys, 12 girls). Measurements of total anterior facial height, upper anterior facial height, lower anterior facial height, total posterior facial height, ramus height, and ratio of lower anterior facial height to total anterior facial height were obtained for all subjects. All data were analyzed and interpreted using a mixed-effects regression model analysis with random effects. RESULTS: From these 4 groups at 14 years old, statistically significant differences were observed between the groups when subjects of the same sex were compared; however, statistical significance was not reached between subjects of opposite sexes in each group. Morphologic differences were clearly evident from the start and became more pronounced with age. There were statistical significances in the initial values and increases with age in all 6 variables except for increases with age in the ratio of lower anterior facial height to total anterior facial height. Statistical significance was also reached for morphologic differences between the annual increases in the ratio of lower anterior facial height to total anterior facial height and lower anterior facial height. In general, individual random variability was high in all variables when compared with the annual changes over time. CONCLUSIONS: Divergent patterns were established early and became more pronounced with age, with anterior facial height dimensions primarily contributing to these differences. Individual variations were so pronounced that caution is recommended for all clinical decisions.

The pattern of facial skeletal growth and its relationship to various common indexes of maturation.

INTRODUCTION: Sequential stages in the development of the hand, wrist, and cervical vertebrae commonly are used to assess maturation and predict the timing of the adolescent growth spurt. This approach is predicated on the idea that forecasts based on skeletal age must, of necessity, be superior to those based on chronologic age. This study was undertaken to test this reasonable, albeit largely unproved, assumption in a large, longitudinal sample. METHODS: Serial records of 100 children (50 girls, 50 boys) were chosen from the files of the Bolton-Brush Growth Study Center in Cleveland, Ohio. The 100 series were 6 to 11 years in length, a span that was designed to encompass the onset and the peak of the adolescent facial growth spurt in each subject. Five linear cephalometric measurements (S-Na, Na-Me, PNS-A, S-Go, Go-Pog) were summed to characterize general facial size; a sixth (Co-Gn) was used to assess mandibular length. In all, 864 cephalograms were traced and analyzed. For most years, chronologic age, height, and hand-wrist films were available, thereby permitting various alternative methods of maturational assessment and prediction to be tested. The hand-wrist and the cervical vertebrae films for each time point were staged. Yearly increments of growth for stature, face, and mandible were calculated and plotted against chronologic age. For each subject, the actual age at onset and peak for stature and facial and mandibular size served as the gold standards against which key ages inferred from other methods could be compared. RESULTS: On average, the onset of the pubertal growth spurts in height, facial size, and mandibular length occurred in girls at 9.3, 9.8, and 9.5 years, respectively. The difference in timing between height and facial size growth spurts was statistically significant. In boys, the onset for height, facial size, and mandibular length occurred more or less simultaneously at 11.9, 12.0, and 11.9 years, respectively. In girls, the peak of the growth spurt in height, facial size, and mandibular length occurred at 10.9, 11.5, and 11.5 years. Height peaked significantly earlier than both facial size and mandibular length. In boys, the peak in height occurred slightly (but statistically significantly) earlier than did the peaks in the face and mandible: 14.0, 14.4, and 14.3 years. Based on rankings, the hand-wrist stages provided the best indication (lowest root mean squared error) that maturation had advanced to the peak velocity stage. Chronologic age, however, was nearly as good, whereas the vertebral stages were consistently the worst. Errors from the use of statural onset to predict the peak of the pubertal growth spurt in height, facial size, and mandibular length were uniformly lower than for predictions based on the cervical vertebrae. Chronologic age, especially in boys, was a close second. CONCLUSIONS: The common assumption that onset and peak occur at ages 12 and 14 years in boys and 10 and 12 years in girls seems correct for boys, but it is 6 months to 1 year late for girls. As an index of maturation, hand-wrist skeletal ages appear to offer the best indication that peak growth velocity has been reached. Of the methods tested here for the prediction of the timing of peak velocity, statural onset had the lowest errors. Although mean chronologic ages were nearly as good, stature can be measured repeatedly and thus might lead to improved prediction of the timing of the adolescent growth spurt.

Natural head position and growth of the facial part of the skull.

The aim of this study was to determine any correlation between natural head position and cranio-cervical growth direction and if natural head position influences facial growth direction. One hundred sixty (160) cephalometric radiographs were examined and cranio-cervical inclinations determined (angles: NS-Ver, NS-OPT, NS-CVT). On the basis of the NS-ML angle, radiographs were divided into two groups: mandibular anteriorotation and posteriorotation. On the basis of the SGo/NMe index, two groups were formed: short-faced and long-faced subjects. The angles NS-Ver, NS-OPT, and NS-CVT describe cranio-cervical inclination. Subjects with anterior mandible growth do position their heads more vertically and have a shorter face, and those with posterior mandible growth tilt their heads more backwards and have a longer face. An adaptive head position can be a factor in altering the direction of facial growth. Determination of head position and mandible growth direction can be an important indicator in patients with TMD treatment.

Effect of complete dentures on craniofacial growth of an ectodermal dysplasia patient: a clinical report.

The aim of this clinical report was to observe the effect of complete dentures on craniofacial growth and development of an ectodermal dysplasia (ED) patient. A complete anodontia patient diagnosed with ED was successfully rehabilitated with conventional complete dentures at the ages of 5, 8, and 10 years. Three sets of complete dentures were made with age-appropriate denture teeth and a bilaterally balanced lingualized occlusal scheme. Periodic follow-up and adjustment when needed was done to maintain proper oral function and esthetics. Serial cephalometric analysis exhibited a marked restriction of forward growth at the anterior nasal spine (ANS) point between 5 and 10 years of age, although there was little change from average in the anteroposterior length of the mandibular body and the height of the mandibular ramus. So, while maxillary growth was reduced, mandibular growth did not significantly change. Cast analysis showed that the increase in arch length was greater than in arch width for both the maxilla and mandible. There was little increase in alveolar ridge height in the anterior region but a considerable increase in the height of the alveolar ridge in the middle and the posterior region. Our findings concluded that the absence of teeth did not affect the growth of the jaws, and it is probable that the denture flange did not arrest the jaw growth, but rather improved the masticatory function by providing good denture stability and retention.

A longitudinal three-center study of craniofacial morphology at 6 and 12 years of age in patients with complete bilateral cleft lip and palate.

In this longitudinal study, the craniofacial morphology and evaluated soft tissue profile changes, at 6 and 12 years of age in patients with complete bilateral cleft lip and palate (CBCLP) were compared. Lateral cephalograms from 148 patients with CBCLP, treated consecutively at three European cleft centers, Gothenburg (n (A) = 37), Nijmegen (n (B) = 26), and Oslo (n (C) = 85), were evaluated. Eighteen hard tissue and ten soft tissue landmarks were digitized. Paired t test, Pearson's correlation coefficients, and multiple regression models were applied for statistical analysis. ANOVA and Tukey-B, as a post hoc test, were used to evaluate the increments and compare centers. Hard and soft tissue data were superimposed using the generalized Procrustes analysis. For Nijmegen, the increments of the variables SNA, ANB, SN-NL, SN-ML, NL-ML, Snss, and Snpg were significantly different than the two other centers (p = 0.041 to <0.001). SNPg increments were significantly different between Nijmegen and Oslo (p = 0.002). The three cleft centers followed different treatment protocols, but the main differences in craniofacial morphology until 12 years of age were the growth pattern and the maxillary and upper incisor variables. Follow-up of these patients until facial growth has ceased, which may elucidate components for improving treatment outcome.

Effects of induced precocious puberty on cranial growth in female Wistar rats.

This investigation examined the effects of pharmacologically induced precocious puberty on cranial growth in Wistar rats. Forty-eight female newborn Wistar rats were divided into two groups: a control group (C) and an experimental group (E), with four subgroups of six animals each. The time interval from birth until sacrifice differed between the subgroups, and was set at 30, 60, 90, and 120 days. An intramuscular single dose (300 µg) of steroid hormone danazol was administered on day 5 after birth, as a means of inducing precocious puberty. Alizarin (2 mg/100 g) was administered to three animals in each subgroup three days prior to sacrifice. Body mass and dates corresponding to the beginning of the oestrous cycle were recorded. Craniometric measurements were undertaken. Histological analysis using light and fluorescence microscopy was then carried out to qualitatively and quantitatively evaluate the spheno-occipital synchondrosis and to visualize bone deposition patterns. The results were analysed with a Student's t-test and analysis of variance. Precocious puberty was effectively induced and differences between groups denoted an earlier maturation in the experimental rats. In qualitative analysis, a significant increase of total synchondrosis width was noted only in group E60, in comparison with C60, and an increase in the E90 subgroup cortical bone width compared with the C90 subgroup. Histomorphometrically, a statistical difference between total width values of subgroups E60 (434.3 µm) and C60 (323.5 µm) was detected. However, body mass and macroscopic measurements did not show statistically significant differences. An appropriate model for studying bone growth associated with precocious puberty in Wistar female rats was not achieved using steroid hormone danazol, when evaluated at 30 day intervals.

Normal ranges of fetal nasal bone length during the second trimester in an Iranian population.

OBJECTIVE: To provide a normal reference range for nasal bone length (NBL) during the second trimester of pregnancy in an Iranian population. METHODS: This cross-sectional study was performed on 3201 fetuses at 15 to 28 weeks of gestational age (GA). Both singleton and twin fetuses were evaluated. The relationship between NBL and GA was determined and percentile values for each gestational week were provided. RESULTS: NBL measurement was obtained in 98% of singleton and 96% of twin fetuses. There was a linear relationship between GA and NBL both in singleton (R(2) = 0.62) and in twin (R(2) = 0.74) fetuses. There was no significant difference between twins regarding NBL (p = 0.18). CONCLUSION: We have provided the normal reference range for NBL during the second trimester in an Iranian population. NBL in singleton and twin fetuses is similar and there is no significant difference between twins regarding NBL.

Pediatric nasal injuries and management.

Although serious trauma injuries are uncommon in the pediatric population, nasal injuries are a more common problem. In this population, many physicians are uncomfortable managing these injuries. The evaluation and treatment of nasal trauma differ considerably in children compared with adult nasal fractures. Poor patient cooperation during the physical exam coupled with significant anatomic differences can present the nasal surgeon with a difficult diagnostic dilemma. The surgical management of pediatric nasoseptal injuries is not without controversy, as disturbing the nasal growth centers can have significant effect on future nasal and midfacial development. This article reviews the diagnostic and therapeutic challenges presented by these injuries for children and provides recommendations to successfully manage nasal injuries in this population.