Data and patterns of transverse dentofacial structure of 6- to 15-year-old children: a posteroanterior cephalometric study

Longitudinal changes in the dental arch width and symmetry in identical and fraternal twins

INTRODUCTION

This study aimed to assess growth-related dental and symmetry changes in the dental arch within and between identical and fraternal twins in mixed and permanent dentition.

METHODS

Three-dimensional scanned dental models of eligible subjects were selected from the Forsyth-Moorrees Twin Study sample. This retrospective cohort study was carried out on 36 identical (18 pairs) and 28 fraternal (14 pairs) twins in mixed dentition and 36 identical (18 pairs) and 38 fraternal (19 pairs) twins in permanent dentition stages on the basis of the availability of the dental casts scanned each year from each group (Table I). Linear measurements from dental casts were performed in patients aged 8-16 years. Student t test and Pearson's correlation were used to compare the symmetry between and within the identical and fraternal twins. The resemblance and heritability patterns were retrospectively obtained from the Pearson correlation coefficient and Falconer's heritability test (H2 = 2 × b). Adjusted mixed-effects estimates and 95% confidence intervals were calculated to test the association between age and dental parameters for both mixed and permanent dentition groups.

RESULTS

Intercanine and intermolar widths significantly increased (P <0.05) during the mixed dentition but became stable after 13 years old. No statistically significant differences were found in arch symmetry between the 2 groups (ie, identical and fraternal) in any of the included measurements. Evaluation of the resemblance and heritability pattern showed nonsignificant results for all variables measured (H2 range, -0.67 to 0.56).

CONCLUSIONS

The dental arch becomes wider at a higher rate in the canine region than the molar region in both the mixed and early permanent dentition. The dental arches of twins develop symmetrically, and their growth is not mainly affected by genetics. Asymmetrical teeth will maintain their relative position to reference planes throughout growth.

Evaluation of Quantitative Aspects of Craniofacial Deformities in Transfusion Dependent Beta-Thalassemia Major Patients: A Cephalometric Study

PURPOSE

To evaluate the quantitative (cephalometric) aspects of the craniofacial deformities in transfusion-dependent beta-thalassemia (TDT) patients.

MATERIALS AND METHODS

Sixty-five TDT patients receiving a regular blood transfusion in the Department of Pediatrics of age group 5 to 8 years (younger) and 15 years and above (older) were compared with control groups of similar age using cephalograms (lateral and posterior-anterior view).

RESULTS AND OBSERVATION

The prevalence of skeletal class II tendency is higher in thalassemic patients that do not improve with age. The thalassemic patients were found to show large angle ANB i.e.. Angle between points point a, nasion and point B (ANB), large flexure angle, small angle SNB i.e.. Angle between points sella, nasion and point B (SNB), and normal angle SNA i.e.. Angle between points sella, nasion and point A (SNA) angles suggestive of retrognathic mandible. The thalassemic patients were observed to have smaller transverse widths and thickened calvarium on the posterior-anterior view.

CONCLUSION

The skeletal class II malocclusion appears to be a manifestation of generalized growth retardation/delayed puberty in thalassemic patients leading to diminished mandibular growth, rather than maxillary prognathism due to marrow hyperplasia.

A Novel Mathematical Method to Diagnose the Transverse Growth Deficit of the Nasomaxillary Complex

The diagnosis of transverse growth deficit of the maxilla in daily clinical practice is carried out mainly through the experience of a well-trained clinician, which implies a lack of objective criteria applicable in a protocolized manner. The objective of this study was to establish a mathematical method to diagnose maxillary compression in relation to the dimensions of the skull and mandible. Methods: Records of 97 cases with an overall mean age of 9.8 ± 2.6 years were analyzed by three experienced orthodontists. The group of transverse compression was comprised of 62 cases and the control group of 35 cases. The main measurements of the widths were made on a frontal teleradiography of the skull (cranial, zygomatic, orbital, maxillary, bigonial and biantegonial width) and a lateral teleradiography of the skull (facial axis, mandibular plane, SNA, SNB, ANB and Wits). It was established that from the cranial width it is possible to predict the group to which each subject studied belongs—the compression group or the control group. A mathematical formula was obtained in the form of logistic regression that allows for the diagnosis of the presence of maxillary compression based on the cranial, maxillary and orbital widths with a sensitivity of 88.7% and a specificity of 77.1%.

Transversal craniofacial development between skeletal maturation stages: A multi-center posteroanterior cephalometric study

Objectives:

The aim of this study is to evaluate the dentofacial transversal norms according to the stages of skeletal maturation in growing Turkish individuals and to determine differences between the genders.

Materials and Methods:

In our multi-centered, cross-sectional retrospective study, in which transversal measurements were made according to skeletal maturation stages (SMSs), posteroanterior radiographs of 572 individuals (292 female, 280 male) with skeletal and dental Class I relationships and good occlusion were examined at the age range of 7–18 years. SMSs were determined using Björk, Grave and Brown hand-wrist radiography. A linear regression model was used for changes of transversal measurements between SMSs, and t-test was used to determine transverse changes between the genders.

Results:

There was no statistically significant difference between females and males in cranial, facial, and nasal width values up to SMS 5. In maxillary, mandibular, maxillary intermolar, and mandibular intermolar width measurements, males had higher values in most stages of skeletal maturation compared to females. Apart from nasal width and maxillomandibular ratio values in females, the regression model in which transversal measurements were dependent variables, and SMS were independent variables was found to be significant. According to cumulative growth percentages, the growth completion in transversal measurements occurred earlier in females.

Conclusion:

Transversal measurements determined according to the stages of skeletal maturation can be a guide for orthodontists in the clinic to determine values that deviate from normal.

Transverse Growth of the Maxillo-Mandibular Complex in Untreated Children: A Longitudinal Cone Beam Computed Tomography Study

The aim of this study is to evaluate the longitudinal transverse growth of the maxillo-mandibular complex in untreated children using the Cone Beam Computed Tomography (CBCT). Two sets of scans on 12 males (mean 8.75 years at T1 and 11.52 years at T2) and 18 females (mean 9.09 years at T1 and 10.80 years at T2) were analyzed using Dolphin 3D imaging. The transverse widths of various maxillary and mandibular skeletal landmarks and the dentoalveolar and dental landmarks at the level of first molars were measured. Overall, there were greater increases in the transverse dimension in the posterior than anterior portions of the maxilla and mandible. The increase in intergonial width of the mandible seems to be primarily due to the lengthening of the mandibular body. The dentoalveolar process at the first molar level increases at an equal rate corono-apically and is independent to the changes in molar inclination. When comparing maxillary dentoalveolar changes with that of the mandible, greater increases were noticed in the maxilla, which might be explained by the presence of sutural growth in the maxilla. Moreover, the first molars maintain their coordination with each other despite the differential increase in the maxillary and mandibular dentoalveolar processes.

Relationships of Reference Points, Planes and Skull Symmetry on Posterior-anterior Cephalograms in Healthy Young Adults

BACKGROUND

Radiological cephalometry is an important diagnostic tool for analyzing the shape and proportions of the skull. Standardized teleradiography of the skull in posterior-anterior (PA) projection provides orientation data on the symmetry and vertical relations of the skull. The comparison of individual findings with normal values places high demands on the selection of a control group. The aim of this study was to characterize a group to be used as a standard for cephalometric comparisons.

PATIENTS AND METHODS

PA teleradiographs of 23 healthy young adults were analyzed. Distances from reference measuring points to the median sagittal plane and the orbital horizontal plane were made. All individuals showed ideal occlusion. None of the participants had been subjected to orthodontic therapy or craniomaxillofacial surgery.

RESULTS

The measurement results showed a high degree of lateral symmetry of the skeletal reference points and planes. Comparison of the vertical reference lines confirmed the symmetrical constitution of the facial skeleton.

CONCLUSION

The study group is suitable for comparison with the cephalometric evaluations of other study groups.

A postero-anterior cephalometric evaluation of different rapid maxillary expansion appliances

BACKGROUND

The purpose of the study was to evaluate dental and skeletal changes induced by tooth-bone-borne, tooth-tissue-borne, and tooth-borne rapid maxillary expansion (RME) appliances using postero-anterior (PA) cephalometric radiographs.

METHODS

A total of 54 patients' (25 boys, 29 girls) PA cephalometric radiographs who had bilateral posterior crossbite and RME treatment were included and divided into three groups according to the type of appliance used during treatment: tooth-bone-borne RME appliance (hybrid Hyrax) (7 boys, 11 girls, mean age 13.28 ± 1.20 years), tooth-tissue-borne RME appliance (TTB) (8 boys, 10 girls, mean age 13.08 ± 1.06 years) and tooth-borne RME appliance (Hyrax) (10 boys, 8 girls, mean age 12.05 ± 1.35 years). Pretreatment (T0) and posttreatment (T1) PA cephalometric radiographs were analyzed with Dolphin software v. 11.7 (Chatsworth, CA). The comparisons of the groups were performed with Two-way analysis of variance. P < 0.05 was considered statistically significant.

RESULTS

Significant and equal increase of right molar relationship and upper intermolar molar widths occurred in all groups. Dental midline discrepancy showed significant increase in only hybrid Hyrax group between T0 and T1. Significant increases were reported for lateronasal width in hybrid Hyrax and tooth-tissue-borne groups (P < 0.05).

CONCLUSIONS

Both skeletal and dental changes were observed after RME in all groups. However, the greatest skeletal changes were seen in hybrid Hyrax and tooth-tissue-borne groups.

Comparative Evaluation of Conventional and OnyxCeph™ Dental Software Measurements on Cephalometric Radiography

Objective

Cephalometry can be measured with traditionally conventional analysing methods (hand tracing), as well as using computers. Many dental softwares have been developed for this purpose. The reliability of these programs are often compared with the conventional method. The aim of the present study was to compare the conventional method of manual cephalometric analysis with a computerized one, OnyxCeph ™ (Image Instruments, Chemnitz, Germany) dental software.

Methods

Lateral cephalometric radiographs of 150 patients (75 males and 75 females) age range 12-34 were traced by two methods. Conventional method and computerized (OnyxCeph) cephalometric analysis method. 2 maxillar, 3 mandibular, 2 maxillo-mandibular, 3 vertical, 7 dental and 1 soft tissue parameters; 10 angular, 8 linear totally 18 cephalometric parameters were measured. Intra-class correlation coefficients were performed for both methods to assess the reliability of the measurements.

Results

The results 9 of 18 parameters were found statistically significant. They were Cd-A distance, Cd-Gn distance, Go-Me distance, GoGnSN angle, ANS-Me distance, upper incisor-NA distance, lower incisor-NB distance, lower incisor-NB angle, overbite distance.

Conclusion

Despite some discrepancies in measured values between hand-tracing cephalometric analysis method and the OnyxCeph cephalometric analysis method, statistical differences were minimal and only Cd-A, Cd-Gn, Go-Me, ANS-Me, GoGnSN° were clinically important for cephalometric analysis OnyxCeph was evaluated as an efficient method to replace conventional method.

Posteroanterior cephalometric analysis of White-American and Chinese adolescents: a cross-sectional study

Objective: To characterize ethnic differences between Chinese and White-Americans between 8.5 and 17.5 years of age, with respect to transverse cephalometric characteristics and to establish transverse craniofacial normative values for Chinese adolescents. Methods: Two-hundred fifty-seven and 547 posteroanterior cephalograms were selected from 35 White-Americans and 157 Chinese with individual normal occlusions. Transverse measurements were obtained and compared between ethnicities to guide determination of normative values for Chinese adolescents. Student's t-test or one-way analysis of variance was used, as appropriate. Results: Chinese girls demonstrated significantly larger measurements than White-American girls at all ages, with the exception of nasal width. Chinese boys exhibited larger measurements than White-American boys at different ages. Chinese boys had larger measurements than girls for most measurements. These data established normative values for Chinese adolescents. Discussion: Ethnic differences existed between Chinese and White-American adolescents with respect to transverse craniofacial measurements. Transverse normative values were established for Chinese adolescents.

Craniofacial growth studies in orthodontic research — lessons, considerations and controversies

The distinguishing features of Class I, Class II and Class III craniofacial growth have been subjects of orthodontic research since the middle of the 20th century. However, the moral and practical issues related to studying craniofacial growth in modern times have presented unresolved challenges to researchers. While previous longitudinal growth investigations are typically based on historical data sets, the cephalometric growth studies of contemporary populations must now rely on cross-sectional data. Furthermore, clinical orthodontic research has faced similar ethical challenges in which therapeutic outcomes are analysed using historical control data. These limitations, amongst others, have obscured the conclusions that can be drawn from both types of studies. This article begins with a review of the defining characteristics of Class I, Class II and Class III growth and then explores the limitations of growth studies and the use of historical control groups in orthodontic research.

Three-Dimensional Analysis of Maxillary and Mandibular Growth Increments

Objective

To analyze changes in the facial, maxillary, and mandibular skeleton in the vertical, sagittal, and transverse dimensions during an orthodontically relevant period of dentofacial development (i.e., between 7 and 15 years of age).

Subjects and Method

This longitudinal study comprised posteroanterior (PA) and lateral cephalograms at 7, 9, 11, 13, and 15 years of 18 untreated Class I subjects with good occlusion. Transverse growth (width) was analyzed on the basis of PA cephalograms and sagittal (depth) and vertical (height) growth by means of lateral cephalograms. For each linear measurement, mean percentage increases were calculated relative to the size at 7 years of age.

Results and Conclusions

Between 7 and 15 years of age, in the whole facial skeleton and the maxilla, percentage increases were most pronounced in the vertical dimension when compared with the sagittal and transverse dimensions. In the mandible, the largest percentage increases were found in both sexes for vertical growth of the ramus, followed by sagittal growth (body length) and then mandibular width. In the sagittal dimension, development was more pronounced in the mandible (at pogonion more than at B point) than in the maxilla (A point). With respect to vertical growth, percentage increases in posterior face height exceeded the increases in anterior face height. When facial shape changes were analyzed between 7 and 15 years of age in both sexes, the ratio facial height/facial width increased and the ratio facial depth/ facial height decreased, which points toward an age-related increasing influence of vertical development.

Dentofacial transverse development in Koreans according to skeletal maturation: A cross-sectional study

Objective

The aim of this study was to establish the normative data of dentofacial transverse dimensions according to the skeletal maturation stage in Korean adolescents with good occlusion, assess gender differences and determine correlations between transverse variables.

Methods

A total of 577 Korean subjects between ages 7 to 19 years and exhibiting skeletal Class I occlusion were categorized by skeletal maturation index (SMI) of Fishman using hand-wrist radiographs. Dentofacial transverse dimensions were assessed using posteroanterior cephalograms. Independent two-sample t-tests were used to analyze differences between genders. Pearson correlation coefficient was used to determine the correlation between transverse measurements.

Results

Dentofacial transverse norms relevant to skeletal maturation stages were established. The average maxillomandibular width difference and ratio at growth completion was 22.16 mm and 77.01% for males; 23.70 mm and 74.06% for females, respectively. Males had greater facial, maxillary and mandibular widths compared to females at every SMI stage. The maxillary and mandibular intermolar widths showed the strongest correlation for both sexes (r = 0.826 for males, r = 0.725 for females).

Conclusions

Dentofacial transverse norms of Korean adolescents were established according to developmental stage. All dentofacial widths were greater in males at growth completion. Maxillary and mandibular intermolar widths were strongly correlated. This study may serve as a guideline for the assessment of dentofacial transverse growth according to skeletal maturation stage in Korean adolescents with good occlusion.

Buccolingual angulation and intermolar width changes in the maxillary first molars of untreated growing children

INTRODUCTION

Buccolingual inclinations of the maxillary permanent molars and intermolar widths increase with growth for Class I subjects. Changes for untreated Class II subjects have not yet been assessed. The aim of this study was to test the hypothesis that changes in palatal inclination of the maxillary molars and intermolar width throughout growth vary between Class I and Class II molar occlusions.

METHODS

Patients were selected from the Forsyth/Moorrees Twin Study. Dental models taken for 6 consecutive years of 55 untreated subjects (28 with Angle Class I and 27 with Angle Class II occlusion) were scanned. The images were superimposed on the palatal rugae, and the angle between a reference plane and the buccolingual inclination plane was used to calculate the buccolingual molar inclination at each time point. The distance between lingual groove points was used to calculate the intermolar width.

RESULTS

All molars showed increasing palatal inclinations over the 6 years. The change for each time interval was statistically significant. Class I subjects demonstrated significantly greater palatal inclination at each time point. The molar inclination changed by means of 4.99° for Class I subjects and 6.25° for Class II subjects. Intermolar width increased continuously (P <0.001) and was significantly greater (P <0.05) for Class I patients.

CONCLUSIONS

These results suggest that palatal inclination of the maxillary permanent first molars occurs continuously between ages 9 and 14 years, with Class II subjects showing greater changes. The intermolar width increases steadily during this time, with Class II subjects having a narrower intermolar width and less change over time.

Maxillary bone defects and their relationship to transverse maxillary discrepancies

Objectives

The relationship between the presence of bone defects (fenestrations and dehiscences) observed in lateral slices in computerized axial tomography (CAT) images and maxillomandibular transverse discrepancies was determined.

Methods

The sample was composed of 160 CAT scan files, corresponding to 9–25-year-old patients, which had been taken prior to orthodontic treatment at a radiology center in Guadalajara, México, from 2009 to 2012. They were grouped by age, and we identified bone defects in maxillary teeth (first and second premolars and first molars). The maxillary (JL-JR) and mandibular (GA-AG) widths were measured, and the maxillomandibular discrepancy ([GA-AG]-[JL-JR]) was calculated. Chi-square and t-tests were performed.

Results

The values of maxillomandibular discrepancies increased with the age of the patient. There was no association between the magnitude of the maxillomandibular discrepancy and the presence of bone defects. The gender of the individual was not a decisive factor in whether bone defects were present.

Conclusion

Bone defects occur in the vast majority of patients pretreatment regardless of the magnitude of the maxillomandibular discrepancy.

Correlation between transverse and vertical measurements in Brazilian growing patients, evaluated by Ricketts-Faltin frontal analysis

INTRODUCTION

Currently in orthodontic diagnosis, besides the lateral cephalometric analysis which evaluates the anteroposterior and vertical direction, the frontal analysis may be added, leading us to another important dimension in space: the transverse dimension.

OBJECTIVE

Few longitudinal samples with the frontal radiograph were published, so this cephalometric study was designed to correlate the transversal and vertical measures by Ricketts-Faltin frontal analysis into two radiographic times.

METHODS

The sample consisted of 45 Brazilian children, 25 girls and 20 boys, all presenting mixed dentition, with balanced facial aesthetics and no previous orthodontic/orthopedic treatment. The initial average age (T1) was 7.7 years and the final (T2) 13.3 years. The measurements evaluated were: FTD, MxTD, NTD, LITD, MdTD (transversal), OVD and TVD (vertical).

RESULTS

All transversal measures were positively correlated with a medium or high correlation with each other and the vertical measurements; only LITD presented a low correlation with these measurements.

CONCLUSIONS

It was concluded that the face has interdependent regions and that this feature remains with growth.

Transverse maxillary and mandibular growth during and after Bionator therapy: study with metallic implants

INTRODUCTION: This study evaluated posteroanterior cephalograms before and after treatment and long term follow-up of Class II division 1 patients treated with bionator. OBJECTIVE: The objective was to demonstrate the transverse growth of maxilla and mandible during and after bionator therapy. METHODS: Measurement of transverse dimensions between posterior maxillary and mandibular implants, as well as the distances between the buccal, gonial and antegonial points were recorded. Measurements were analyzed at three periods: T1 = before bionator therapy, T2 = after bionator therapy and T3 = 5.74 years after T2. RESULTS: There was statistically significant transverse increase due to growth and/or treatment for all variables, except for the distance between the anterior maxillary implants. CONCLUSIONS: During the study period only the anterior maxillary area did not show transverse growth.

Posteroanterior cephalometric norms for an adolescent Kuwaiti population

The aim of the study was to establish posteroanterior (PA) cephalometric norms for adolescent Kuwaitis of an age comparable with the start of comprehensive orthodontic treatment, and to compare these with similar normative data, considering a difference of 2.0 mm or degrees as clinically significant. Digital PA cephalograms of 159 13- to 14-year-old Kuwaitis (81 boys and 78 girls) with untreated ideal occlusions were evaluated. Anatomic landmarks were identified directly on digital computer images and linear and angular measurements were calculated electronically. Mean values (norms), standard deviations, and ranges were calculated for the parameters. Student's t-tests were employed to test for gender differences. The dental norms were clinically similar to those of Ricketts' analysis, but the ranges of the skeletal dental width and relationship measurements were clinically larger. Only the ranges of skeletal symmetry measurements were larger. Regarding the four dental to skeletal relationships, the norms were larger only for the molar to jaw relationship, while the ranges were larger for all. No gender differences were detected after Bonferroni adjustments. The findings suggest clinically significant racial differences in PA cephaolometric norms with minimal gender differences at adolescence. The ranges of the various parameters in adolescent subjects with natural development of an ideal occlusion are considerably larger than those suggested in Ricketts' analysis system.

Transverse craniofacial dimensions in Angle Class II, Division 1 malocclusion according to breathing mode

The aim of this longitudinal study was to assess the relation between the transverse craniofacial dimensions of subjects with Class II, Division 1 malocclusion and the breathing mode presented by them. Forty Angle Class II, Division 1 malocclusion subjects of both genders participated in the study, 23 of which were predominantly nose breathers and 17 were predominantly mouth breathers. The mean age ranged from 10 years and 9 months to 14 years--Age range 1; and from 13 years and 4 months to 16 years and 6 months--Age range 2. Measurements of six transverse craniofacial dimensions were performed in P-A teleradiographs: Total Sphenoid, Total Zygomatic, Total Nasal Cavity, Total Maxilla, Total Mastoid and Total Antegonion. The transversal craniofacial dimensions were measured and compared in both groups at age ranges 1 and 2. The longitudinal assessment of age ranges 1 and 2 showed that there was no statistically significant influence of the breathing mode on the craniofacial dimensions evaluated, or on the alteration of these dimensions. Breathing mode had no influence on craniofacial development in the sample studied.

Transverse stability of 3-piece Le Fort I osteotomies

PURPOSE

The transverse dentoalveolar and skeletal stability of multipiece Le Fort I osteotomies with 3 different techniques was investigated.

MATERIALS AND METHODS

The records of 87 patients undergoing bimaxillary osteotomies with 3-piece Le Fort I osteotomy were evaluated. According to the surgical technique of maxillary expansion, the subjects were divided into 3 groups: unilateral palatal osteotomy (group A), bilateral palatal osteotomy (group B), and unilateral palatal osteotomy with fixation of the palatal vault with a resorbable plate (group C). In group A palatal bone grafts were used in 9 patients. Posterior-anterior cephalograms and dental casts were taken before surgery (T1), immediately after surgery (T2), and after a follow-up of 12 to 15 months (T3). The skeletal base was measured between the intersections of the lateral contour of the maxillary alveolar process and the lower contour of the maxillo-zygomatic process. Dentoalveolar width was measured between the first premolars and the first molars. According to the magnitude of expansion, the groups were divided into the following subgroups: negative (constriction), 0 to 2 mm, greater than 2 mm to 4 mm, and greater than 4 mm. An analysis of variance with Bonferroni correction was used to compare the demographic and treatment characteristics and the surgical and postsurgical transverse movements of the 3 study groups. The paired t test was run to evaluate the surgical changes (T2 - T1) and the postsurgical stability (T3 - T2). The influence of palatal bone grafts and downgrafting of the maxilla on the amount of relapse was investigated with the unpaired t test.

RESULTS

The study variables (T1), the surgical changes (T2 - T1), and the postsurgical changes (T3 - T2) showed no significant differences between the 3 study groups. However, a tendency for less relapse in cases with major expansion was seen in group C. The mean expansion of the entire sample was 2.13 mm at the skeletal base, 1.11 mm in the premolar region, and 1.99 mm in the molar region. Mean relapses of 0.20 mm (9%) at the skeletal base, 0.76 mm (68%) in the premolar region, and 1.20 mm (60%) in the molar region were seen. Palatal bone grafts had no significant effect on the postsurgical changes in group A. Anterior and posterior downgrafting did not result in significantly more relapse.

CONCLUSIONS

Surgical expansion of the maxilla provides stable results at the maxillary skeletal base but high relapse rates in the dentoalveolar area. Preoperative orthodontic expansion is one of the main sources of transverse relapse. Fixation of the palatal vault with resorbable plates is a possible technique to improve transverse stability. Larger samples are necessary to provide statistical significance.

Morphologic changes of the palate after rapid maxillary expansion: a 3-dimensional computed tomography evaluation

INTRODUCTION

The purpose of this retrospective study was to estimate the area change of the palate after rapid maxillary expansion (RME) in the early mixed dentition stage by using a 3-dimensional (3D) helical computed tomography (CT) scanning technique. In addition, linear changes in the maxillary arch were evaluated.

METHODS

The treated sample consisted of 43 children (mean age, 9 years 1 month) treated with a bonded RME appliance. The untreated control group consisted of 7 children (mean age, 9 years 3 months). Pretreatment and posttreatment dental casts were evaluated by using 3D helical CT scanning procedures. The Student t test was used to compare the linear, area, and angular differences between the treatment times.

RESULTS

RME produced clinically significant increases in interdental widths across the canines, the deciduous first molars, and the permanent first molars in the maxillary arch. Significant increases in cross-sectional area were observed across the permanent first molars (15.3 mm(2)). There was marked variability in the buccal tipping of the permanent first molars.

CONCLUSIONS

Three-dimensional helical CT scanning is an accurate and cost-effective method of assessing dental cast morphologic changes. It can also provide fast and accurate data acquisition and subsequent analysis.

Dental arch widths and mandibular-maxillary base widths in Class III malocclusions from ages 10 to 14

INTRODUCTION

Evaluations of the dental arch widths and mandibular-maxillary base are needed for a comprehensive dentofacial analysis in subjects with Class III malocclusion. The aim of this study was to analyze the development of the dental arches and the skeletal mandibular-maxillary bases in untreated subjects with Class III malocclusions.

METHODS

Two groups of subjects, 1 with Class III malocclusion and the other with Class I malocclusion, were examined. Maxillary skeletal base width, biantegonial widths, and maxillary and mandibular intermolar widths were determined on posteroanterior cephalograms at annual intervals between the ages of 10 and 14 years.

RESULTS

Maxillary skeletal base widths and intermolar widths in the Class III subjects were significantly smaller than those in the Class I subjects (P <.05). No statistically significant differences were found among the groups for skeletal mandibular width or intermolar width for the total observation period. The deviations in molar differences increased from ages 10 to 14 in the Class III group.

CONCLUSIONS

The main transverse deficiencies in the Class III group were maxillary deficiencies in both skeletal and dental widths. The deviations in molar differences appear to become larger from age 10 to age 14.

Surgical cephalometrics: applications and developments

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Describe the historical origins of modern cephalometry. 2. Identify common landmark points on the lateral cephalogram. 3. Describe multiple common clinical uses for cephalometry. 4. Exhibit knowledge of developments in imaging and analysis alternatives.

BACKGROUND

Interest in the dimensions of the human head has been present since antiquity. Proportional analysis and measures from cadaveric specimens led to the development of radiologic image capture and analysis on living subjects. These techniques were originally applied to establishing normative values, documenting growth, and diagnosing dentofacial disharmonies. This article reviews the origins of cephalometric methodology and current developments and applications.

METHODS

The authors conducted a MEDLINE search and review of all English language articles using the keywords "cephalometric" and "cephalometrics."

RESULTS

Cephalometrics have undergone substantial use and development since the introduction of radiologic imaging on living human subjects in 1931. Although frequently associated with orthognathic surgery, cephalometrics have been applied to a number of conditions involving altered craniofacial morphology. Advances in imaging and computing have led to increased interest in three-dimensional and non-x-ray-based assessment of the human head. Mathematical models have been applied to standard cephalometric information to increase the descriptive accuracy of the complex shapes involved.

CONCLUSIONS

Cephalometric techniques and analyses are versatile tools that can be applied to a wide variety of clinical scenarios involving the craniofacial region. New technologies and expanded applications promise to continue the development and use of this well-established methodology.

Long-term Stability of Unilateral Posterior Crossbite Correction

OBJECTIVE

To evaluate the stability of orthodontically corrected unilateral posterior crossbite in patients treated either by rapid maxillary expansion or with slow expansion devices in the early (mean age 7.2 years, n = 50) or late mixed dentition (mean age 9.9 years, n = 50).

MATERIALS AND METHODS

The observation periods were approximately 8 years for the early treatment groups and 6.5 years for the late treatment groups. The measurements were made on plaster casts at the following time points: before treatment (T1), after crossbite correction (T2), at the end of active orthodontic treatment (T3), and about 2 years after the end of active treatment (T4). Midline deviation and the skeletal classification of the malocclusion were also evaluated.

RESULTS

Almost 80% of the treated patients showed long-term stability of the corrected unilateral posterior crossbite. More than 70% of the patients were treated for the mandibular midline deviation. At the end of active treatment, 50% of the patients showed a skeletal Class III craniofacial morphology.

CONCLUSIONS

The results emphasize that determination of the correct treatment approach for the individual patient is the basic principle underlying the therapeutic success in unilateral crossbite cases. In patients where a broad lower arch is a cofactor in the etiology of the lateral crossbite, the treatment approach should be focused on both arches and not be limited to the constricted upper arch.

Long-term stability of unilateral posterior crossbite correction

OBJECTIVE

To evaluate the stability of orthodontically corrected unilateral posterior crossbite in patients treated either by rapid maxillary expansion or with slow expansion devices in the early (mean age 7.2 years, n = 50) or late mixed dentition (mean age 9.9 years, n = 50).

MATERIALS AND METHODS

The observation periods were approximately 8 years for the early treatment groups and 6.5 years for the late treatment groups. The measurements were made on plaster casts at the following time points: before treatment (T1), after crossbite correction (T2), at the end of active orthodontic treatment (T3), and about 2 years after the end of active treatment (T4). Midline deviation and the skeletal classification of the malocclusion were also evaluated.

RESULTS

Almost 80% of the treated patients showed long-term stability of the corrected unilateral posterior crossbite. More than 70% of the patients were treated for the mandibular midline deviation. At the end of active treatment, 50% of the patients showed a skeletal Class III craniofacial morphology.

CONCLUSIONS

The results emphasize that determination of the correct treatment approach for the individual patient is the basic principle underlying the therapeutic success in unilateral crossbite cases. In patients where a broad lower arch is a cofactor in the etiology of the lateral crossbite, the treatment approach should be focused on both arches and not be limited to the constricted upper arch.

Dental Arch Widths and Mandibular-Maxillary Base Width in Class III Malocclusions with Low, Average and High MP-SN Angles

Objective: To analyze the development of the dental arches and skeletal mandibular-maxillary bases in untreated Class III malocclusions with low averages and high mandibular plane angles in subjects aged 10 to 14.

Materials and Methods: The records of 50 untreated Japanese girls with Class III malocclusions at age 10 were selected from the files of patients pending orthodontic surgery. The patients included those with low (≤27°), average (27° through 37°) and high (&gt;37°) mandibular plane angles. The maxillary skeletal base width, biantegonial width, and maxillary and mandibular intermolar width were determined on posteroanterior cephalograms obtained at annual intervals when subjects were between 10 and 14 years of age. The difference between the maxillary and mandibular intermolar width was also calculated and reported.

Results: All skeletal and dental transverse widths in the high-angle group were significantly smaller than those in the low-angle group (P &lt; .05) from ages 10 to 14. On the other hand, the maxillary to mandibular molar difference was the same for the three groups (P &gt; .05) at each age. The deviations in molar differences did increase from age 10 to age 14 in all three groups.

Conclusion: Mandibular plane angles might play a stronger role in the transverse skeletal growth of the maxilla and the mandible than the transverse dental growth of the maxilla and the mandible.

Nasal airway measurements in children treated by rapid maxillary expansion

BACKGROUND

Rapid maxillary expansion is an orthodontic procedure that is commonly used to widen the maxilla. It is generally admitted that this technique is effective to correct palate narrowing, whereas there has not been agreement on the effect of this procedure in nasal parameters. The availability of a reliable and objective technique to assess the geometry of nasal cavities, such as acoustic rhinometry, stimulated the present investigation.

METHODS

Twenty-seven children, undergoing rapid maxillary expansion, were evaluated by rhinomanometry and acoustic rhinometry. Postero-anterior radiographs were taken in 15 patients for cephalometric measurements. Examinations were performed before expansion treatment and after 12 month follow-up and compared to the measurements obtained from an untreated control group.

RESULTS

With regard to rhinomanometry, we recorded a significant reduction in nasal airway resistance (NAR) after the orthodontic procedure only in decongestion. Using acoustic rhinometry, we found a significant increase in total minimum cross-sectional areas (TMCA) and total nasal volume (TNV) after the expansion both in basal and decongested conditions. Also, nasal cavity width and interzygomatic distance had a significant mean increase after the treatment. Comparison of measures between the control group and the treated group showed that the increase in TMCA and TNV, as well as the decrease in NAR, were significantly greater in the treated group in both basal and decongested conditions.

CONCLUSION

We demonstrated that rapid maxillary expansion is an effective procedure in widening nasal cavities with respect to an untreated control group and that the reported improvement in nasal breathing after palatal expansion, is a consequence of an increase in nasal size.

Transverse growth of the maxilla and mandible in untreated girls with low, average, and high MP-SN angles: A longitudinal study

INTRODUCTION

The purpose of this study was to investigate maxillary and mandibular transverse growth in untreated female subjects with low, average, and high mandibular plane angles longitudinally from ages 6 to 18.

METHODS

Eighty-one untreated white girls with low (< or = 27 degrees , n = 16), average (> 27 degrees to < 37 degrees , n = 41), and high (> or = 37 degrees , n = 24) mandibular plane angles at age 6 were selected from the Bolton-Brush and Burlington Growth Studies. For each subject, longitudinal posteroanterior cephalograms at different ages (from ages 6 to 18) were traced, and the widths of maxilla and mandible were measured. All the measurements were converted by using a magnification factor of 8.5% (the subject-to-film distance was set at 13 cm).

RESULTS

At age 6, the high-angle group had narrower maxillary and mandibular widths than the low-angle group, and this trend continued until age 18. From ages 6 to 14, maxillary width showed a steady and similar rate of increase for all 3 groups (0.90-0.95 mm per year), yet a plateau was reached at age 14 for all groups. Mandibular width increased at a steady rate (about 1.6 mm/year) for all 3 groups until age 14, and a plateau was reached for the high-angle group. For the low- and average-angle groups, mandibular growth continued from ages 14 to 18 but at a slower rate (0.85 mm and 0.39 mm per year, respectively).

CONCLUSIONS

Vertical facial patterns (with low or high mandibular plane angles) might play a strong role in the transverse growth of the maxilla and the mandible.

Transverse skeletal base adaptations with Bionator therapy: a pilot implant study

The purpose of this randomized, controlled trial was to evaluate transverse skeletal base adaptations to Bionator therapy. The sample included 25 patients (15 male, 10 female) aged 6.9 to 11.2 years with Class II Division 1 malocclusion. The patients were randomly allocated to either a control (n = 11) or treatment (n = 14) group and followed longitudinally for approximately 12 months. Treatment consisted of a Bionator only, constructed to remain approximately 2 mm from the buccal dentition. Transverse maxillary and mandibular changes were evaluated cephalometrically according to 4 bilateral maxillary and 2 bilateral mandibular implants. Untreated Class II controls exhibited significant increases between posterior maxillary implants but no significant changes between the anterior maxillary or mandibular implants. There were no significant width differences between the control and treated groups before treatment. Posterior maxillary implant widths increased significantly (P < .05) in both groups, but the treated group showed significantly greater width increases than the control group. The treated group also showed greater increases between mandibular implants, but the differences were not statistically significant. These results suggest that transverse skeletal base adaptations occur as a result of Bionator therapy.

Facial scoliosis due to sternocleidomastoid torticollis: a cephalometric analysis

Facial scoliosis can be caused by either the plagiocephaly which arises from unilateral coronal suture synostosis, or by the effects of sternocleidomastoid torticollis. Despite publications which have presented the key clinical and radiographic craniofacial differentiating features, confusion between the two still persists. This report presents the essential cephalometric features found in sternocleidomastoid torticollis, which may be applied to confirm the diagnosis in those cases which present late, and which do not exhibit the characteristic features of synostosis.

Craniofacial skeletal deviations following in utero exposure to the anticonvulsant phenytoin: monotherapy and polytherapy

OBJECTIVE

To identify and quantify the craniofacial effects from prenatal exposure to phenytoin monotherapy and polytherapy using cephalometric, hand-wrist, and panoramic radiographs and to determine if such deviations persist with age.

DESIGN

Craniofacial structures of 28 anticonvulsant-exposed individuals were evaluated using 20 landmarks in lateral cephalometric radiographs and 19 landmarks in frontal cephalometric radiographs. Skeletal maturity was assessed using hand-wrist radiographs. Dental maturity and the presence of dental anomalies were evaluated using panoramic radiographs. Eleven individuals were re-evaluated 7 years later, on average, to determine the persistence of any measured deviations.

SETTING AND SAMPLE POPULATION

Department of Growth and Development, Harvard School of Dental Medicine and Massachusetts General Hospital. Patients were recruited from several sources.

OUTCOME MEASURE

The evaluated dimensions included linear, angular, and proportional measures.

RESULTS

The most common deviations were decreased height and length of the maxilla, decreased length of the posterior cranial base, length of the mandible, cranial width and level of the cribriform plate, and a decrease in the Wits Appraisal assessment. The deviations were more significant in the polytherapy-exposed individuals than in the monotherapyexposed individuals. These deviations, especially in the maxilla, persisted with age as revealed in a re-evaluation of 11 individuals.

CONCLUSION

The craniofacial skeletal findings among individuals exposed in utero to phenytoin monotherapy or phenytoin polytherapy, when considered in aggregate, suggest a mild pattern of maxillary hypoplasia that becomes more pronounced with age.

Craniofacial morphology and dental age in children with Silver-Russell syndrome

OBJECTIVES

This investigation is a part of a multidisciplinary descriptive evaluation of the Silver-Russell syndrome (SRS). The aim of this study was to describe the craniofacial morphology, occlusion and dental age in children with the SRS.

DESIGN

A descriptive literature-controlled study.

SETTING AND SAMPLE POPULATION

Sixteen children diagnosed as having SRS, 10 boys and six girls, aged 4.4-14.5 years, were referred from different parts of Sweden to the Queen Silvia Children's Hospital, Göteborg University.

EXPERIMENTAL VARIABLE

Facial morphology was measured on lateral and postero-anterior radiographs. Occlusion, tooth eruption and palatal height were measured on casts, and dental maturity was evaluated on orthopantomograms.

OUTCOME MEASURE

Linear and angular measurements were obtained from lateral radiographs and the ratios of the linear measurements from the postero-anterior radiographs. The degree of tooth calcification shown on orthopantomograms was taken as a measure of dental maturity. Biometric measurements were taken and the degree of tooth eruption was recorded from the dental casts. The SRS children were compared with reference groups with t-test and z-scores.

RESULTS

Overall, SRS children were found to have smaller linear facial dimensions and deviations in the facial proportions, such as a small retropositioned, and steeply inclined maxilla and mandible, and a proportionally larger anterior facial height in relation to the posterior facial height. In 40% of them a smaller facial height or length on one side (facial asymmetry) was correlated to the smaller side of the body. The frequency of malocclusions was higher, and the palatal height showed a tendency towards an increase. Dental maturity was within normal limits, while the time of tooth eruption was slightly delayed.

CONCLUSIONS

The deviating facial morphology described above is a part of the syndrome, which is characterized by short stature, growth hormone deficiency and asymmetries of the body. The higher percentage of malocclusions in the SRS children might lead to a greater need of orthodontic treatment.

Long-term effects of rapid maxillary expansion: a posteroanterior cephalometric evaluation

The aim of this study was to investigate long-term effects induced by rapid maxillary expansion (RME), followed by comprehensive orthodontic treatment, in a sample of 42 patients compared with normal growth changes in a sample of 20 subjects. Treated subjects underwent Haas-type RME with 2 turns a day (0.25 mm per turn) until the expansion screw reached 10.5 mm (about 21 days). The Haas expander was kept on the teeth as a passive retainer for an average of about 2 months. Immediately after the Haas expander was removed, fixed standard edgewise appliances were placed. Posteroanterior cephalograms were analyzed for each subject in both groups at T1 (pretreatment) and at T2 (long-term observation). The mean age at T1 was 11 years 10 months for both the treated and the control groups. The mean ages at T2 also were comparable (20 years 6 months for the treated group, and 17 years 8 months for the control group). The study included transverse measurements on dentoalveolar structures, maxillary and mandibular bony bases, and other craniofacial regions (nasal, zygomatic, orbital, and cranial). RME followed by edgewise appliance therapy appears to be an effective procedure to increase transverse facial dimensions in the long term, at both the skeletal and the dentoalveolar levels. Significant pretreatment deficiencies in maxillary width, maxillary incisor apex width, and maxillary first molar width remained corrected at a mean age of about 20 years. The initial deficiency in lateroorbital width was also eliminated.

Maxillary and mandibular width changes studied using metallic implants

The purpose of this implant study was to evaluate the transverse stability of the basal maxillary and mandibular structures. The sample included 25 subjects between 12 and 18 years of age who were followed for approximately 2.6 years. Metallic implants were placed bilaterally into the maxillary and mandibular corpora before treatment. Once implant stability had been confirmed, treatment (4 first premolar extractions followed by fixed appliance therapy) was initiated. Changes in the transverse maxillary and mandibular implants were evaluated cephalometrically and two groups (GROW+ and GROW++; selection based on growth changes in facial height and mandibular length) were compared. The GROW++ group showed significant width increases of the posterior maxillary implants (P <.001) and the mandibular implants (P =.009); there was no significant change for the anterior maxillary implants. The GROW+ group showed no significant width changes between the maxillary and mandibular implants. We conclude that (1) there are significant width increases during late adolescence of the basal mandibular and maxillary skeletal structures and (2) the width changes are related with growth potential.

Skeletal and dental changes after maxillary expansion in the mixed dentition

The purpose of this study was to compare skeletal and dental aspects of three different expansion methods in the mixed dentition period in sagittal, vertical, and transversal planes, treatment periods, complications, and relapse tendencies in early periods. Patients with unilateral or bilateral posterior crossbites in the mixed dentition were studied. They were divided into three groups of 10 patients in each group. The first group received treatment with removable plates for semirapid maxillary expansion; the second group with quad-helix appliances for slow maxillary expansion; and the third group with conventional fixed hyrax appliances for rapid maxillary expansion (RME). Lateral and posteroanterior cephalometric films, occlusal films, and dental casts were taken before and after expansion, and after retention with the same appliances. Cephalometric and dental cast analyses were made. Both skeletal and dental changes were observed after all three expansion methods.