Linear Mandibular Measurements: Comparison between Orthopantomograms and Lateral Cephalograms

Non-progressive mandibular changes in children with Type I and II craniofacial microsomia

OBJECTIVE

To describe the mandibular growth of craniofacial microsomia (CFM) patients during early childhood to adolescence with attention to symmetry.

MATERIALS AND METHODS

Altogether 61 CFM patients were studied at the Cleft Palate and Craniofacial Center, Helsinki University Hospital between 1986 and 2006. In this cohort study, we measured and analysed 293 radiographs (posteroanterior, panoramic and lateral); 165 radiographs of 40 patients met the final inclusion criteria. The vertical height of the ramus in anteroposterior and panoramic radiographs, the length of the mandible in anteroposterior radiographs and the maxillary protrusion and mandibular retrognathia in lateral cephalograms were measured in four different age groups.

RESULTS

A statistical difference existed between the groups in the vertical height of the ramus and in the mandibular length. The vertical height of the ramus measured from the panoramic radiograph grew on both sides, and the ratios remained unchanged. In the sagittal dimension, the maxilla and mandible grew forward, but no significant differences emerged between the groups.

CONCLUSIONS

Results suggest that mild-type CFM is not progressive in nature. During growth, mandibular asymmetry measured in the horizontal, vertical and sagittal planes did not increase.

Methods of Definitive Correction of Mandibular Deformity in Hemimandibular Hyperplasia Based on Radiological, Anatomical, and Topographical Measurements-Proposition of Author's Own Protocol

In order to fully evaluate and establish the degree of bone overgrowth, various radiological studies are essential in the careful planning of the amount of surgical excision. In the presented paper, the authors use self-designed anatomo-topographical reference points for planning the surgeries. Routine panoramic radiographs and low-dose computed tomography based on anatomical landmarks help in measuring the proportions of mandibular bone overgrowth with the following preoperative anatomical landmarks: (Go-Go), (Go(Right)-Gn), (Go(Left)-Gn), and (Me−Gn). Measurements taken at selected points and landmarks (gonion-gnathion/gnathion-menton) are easy to conduct. In the authors’ proposal, the main key factor is total chin correction, which is necessary in cases of severe overgrowth; when F0 > C and Go-Gn>, there is >7 mm of vertical bone overgrowth, and the mandibular canal is positioned <5 mm from the inferior mandibular border—MIB. Larger overgrowths (>7 mm) have a greater outcome on the final symmetry than smaller overgrowths. As no guidelines are known, the authors present their own proposal.

A semi-automatic three-dimensional technique using a regionalized facial template enables facial growth assessment in healthy children from 1.5 to 5.0 years of age

Objectives

To develop a semi-automatic technique to evaluate normative facial growth in healthy children between the age of 1.5 and 5.0 years using three-dimensional stereophotogrammetric images.

Materials and Methods

Three-dimensional facial images of healthy children at 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0 years of age were collected and positioned based on a reference frame. A general face template was used to extract the face and its separate regions from the full stereophotogrammetric image. Furthermore, this template was used to create a uniform distributed mesh, which could be directly compared to other meshes. Average faces were created for each age group and mean growth was determined between consecutive groups for the full face and its separate regions. Finally, the results were tested for intra- and inter-operator performance.

Results

The highest growth velocity was present in the first period between 1.5 and 2.0 years of age with an average of 1.50 mm (±0.54 mm) per six months. After 2.0 years, facial growth velocity declined to only a third at the age of 5.0 years. Intra- and inter-operator variability was small and not significant.

Conclusions

The results show that this technique can be used for objective clinical evaluation of facial growth. Example normative facial averages and the corresponding facial growth between the age 1.5 and 5.0 years are shown.

Clinical Relevance

This technique can be used to collect and process facial data for objective clinical evaluation of facial growth in the individual patient. Furthermore, these data can be used as normative data in future comparative studies.

The effects of a corticotomy on space closure by molar protraction using TSADs in patients with missing mandibular first molars

INTRODUCTION

The purpose of this study was to evaluate the effects of a triangular-shaped corticotomy on the protraction of second and third molars in patients with missing mandibular first molars.

SUBJECTS AND METHODS

The corticotomy and non-corticotomy groups consisted of sixteen first molars in fifteen patients (28.6 ± 9.4 years) and nineteen first molars in fifteen patients (26.6 ± 8.4 years), respectively. A triangular-shaped corticotomy was performed between the second premolar and molar. Temporary skeletal anchorage devices (TSADs) were placed between the first and second premolars in both groups. Mandibular dentition variables were measured on the pre and post-treatment panoramic radiographs and lateral cephalograms. Analysis of covariance was performed.

RESULTS

The corticotomy group exhibited 2.8 mm more inter-radicular correction between the second molar to second premolar roots (P < .001) and 1.6 mm more inter-radicular distance correction between the third molar to second premolar roots compared to the non-corticotomy group (P < .01). The corticotomy group required 5.5 months less treatment time for space closure (P < .05), but the total treatment time was the same for both groups.

CONCLUSIONS

The inter-radicular distance between the mandibular second premolar and molar and treatment times for space closure was significantly reduced in the corticotomy group.

Digital Radiographic Study of Gonial angle in Forensic Odontology in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction:

Gonial angle measurements serve as an important parameter of the craniofacial complex and are usually studied on lateral cephalograms, but recently panoramic radiographs have also been used. The aim of this study is to measure the gonial angle using orthopantomogram and lateral cephalogram based on age, gender, ethnicity, and skeletal malocclusion in a tertiary care hospital.

Methods:

This is a descriptive cross-sectional study comprising 350 selected radiographs of apparently healthy individuals collected for a period of one year, from the Department of Oral Radiology of a tertiary care centre of Nepal. Gonial angle measurements were recorded from digital panoramic radiograph (both right and left side) and lateral cephalogram. Data was collected in terms of age, gender, ethnicity, and skeletal malocclusion and then statistically analysed using the Statistical Package for the Social Sciences version 20.

Results:

The mean gonial angle for panoramic right, left and lateral cephalogram was 122.490±7.570, 123.620±7.060, and 124.150±6.910, respectively. There was a decrease in the mean values of the gonial angle observed as age advances seen in all the radiographs. The gonial angle measured in Class III malocclusion was higher in all the radiographs, followed by Class II and Class I. Gonial angles obtained in females were higher than the males in all the radiographs. Finally, the Aryan population showed a higher gonial angle compared to the Mongolian population in all the radiographs.

Conclusions:

Panoramic radiograph (left side), could be considered as a reliable tool to measure the gonial angle.

Accuracy of custom temporomandibular joint replacement surgery using a virtual surgical planning protocol

BACKGROUND

Accurate placement of TMJ implant components may be facilitated by virtual surgical planning (VSP) technologies. The aim of this study was to assess the accuracy of a typical VSP protocol and describe the pattern of surgical error associated with total alloplastic TMJ replacement.

METHODS

A retrospective analysis was undertaken on 40 adult patients who were implanted with a fully customised, 3D printed TMJ prosthesis due to end-stage TMJ disease. Planned TMJ implant position based on preoperative CBCT images was compared with final position on postoperative OPGs using a previously validated linear rescaling method. Translational discrepancy was described in the anterior-posterior direction and superior-inferior direction. Rotational discrepancy was described as anterior or posterior.

RESULTS

Lin's concordance between preoperative and postoperative position was 0.97, with no significant differences (p > 0.05). The Bland-Altman analysis showed a 95% limit of agreement between planned and final position of - 5.9 to 5.4 mm. Overall, final implant position was more anterior (0.4 mm), superior (0.4 mm) and posteriorly rotated (2.4°) compared with planned position.

CONCLUSION

The use of VSP in TMJ replacement surgery results in accurate implant placement with good agreement between planned and final implant position. Discrepancies in planned and final implant position tended to result in the mandibular component of the implant being translated anterior superiorly and rotated posteriorly, with potential implications for the biomechanical performance of the implant and overall device longevity. These results should be used to assist TMJ surgeons pre- and intraoperatively to facilitating accurate implant positioning and optimal surgical rehabilitation.

Pseudo Hemifacial Microsomia With Condylar-Coronoid Collapse: New Therapeutic Approach in Growing Patients

The purpose of this study is to describe the management of 2 dimorphic patients affected by Hemimandibular Hypoplasia with Condylar-Coronoid Collapse (HH-CCC), also called Pseudo Hemifacial Microsomia, where the orthopedic treatment gave an excellent long-term follow-up. The patients were a 7-year-old female and a 6-year-old male with a HH-CCC on the left side, an asymmetrical face with chin deviation, class II dental malocclusion and canting of the occlusal plane. An X-ray evaluation and clinical observation confirmed the unilateral mandibular deficiency and the collapse of the condyle on the coronoid process on the affected side. The treatment plan consisted of the use of an asymmetrical functional appliance with a vertical screw. The appliance was gradually activated on the vertical plane on one side by a screw incorporated on an acrylic plate. It was used for 22 hours/day, including sleep time but not during meals. This treatment improved the patient' s facial appearance. HH-CCC showed a positive response to functional therapy.

Costochondral graft in growing patients with hemifacial microsomia case series: Long-term results compared with non-treated patients

OBJECTIVE(S)

The aim of this study was to evaluate the long-term effectiveness of costochondral graft in hemifacial microsomia (HFM) type III patients.

SETTINGS AND SAMPLE POPULATION

A sample of 10 patients affected by HFM type III treated during growth in the same Centre with costochondral graft (CCG patients group) is compared with a control group (CG) sample of 10 non-treated patients affected by the same malformation in order to understand whether surgery during growth provides advantages in terms of bony and facial symmetry after an 8-year follow-up.

MATERIALS AND METHODS

The growth of the CCG was assessed on panoramic X-rays. To assess facial symmetry, a photometric evaluation on the frontal view was carried out.

RESULTS

In CCG patients group the graft grown in mean less than the healthy ramus, a good facial symmetry was achieved after surgery, but was lost in the majority of the cases at the most recent control. In CG, occlusal canting slightly increased and facial asymmetry was relatively stable during the years.

CONCLUSION

In patients with a congenital deformity, restoring the height of the ramus leads to an immediate restitution of facial symmetry, but in the long term, there is a return to the asymmetrical pattern. In CG, the asymmetry is stable during years with no increase of the facial deformity.

Factors associated with spontaneous mesialization of impacted mandibular third molars after second molar protraction

OBJECTIVES

To investigate factors associated with spontaneous mesialization of impacted third molars after second molar protraction to close the space caused by a missing mandibular first molar (L-6) or retained deciduous mandibular second molars with a missing succedaneous premolar (L-E).

MATERIALS AND METHODS

Panoramic radiographs of patients treated with mandibular second molar protraction to close the space due to missing L-6 or L-E (14 males, 36 females, mean age = 18.6 ± 4.4 years) were analyzed before treatment (T1) and after second molar protraction (T2). Factors associated with the amount of third molar mesialization were investigated using regression analyses.

RESULTS

Mandibular second molars were protracted by 5.1 ± 2.1 mm and 5.8 ± 2.7 mm, measured at the crown and root furcation, respectively. After second molar protraction, third molars showed spontaneous mesialization by 4.3 ± 1.6 mm and 3.8 ± 2.6 mm, measured at the crown and root furcation, respectively. Nolla's stage of the third molar at T1 (B = 0.20, P = .026) and second molar protraction time (B = 0.04, P = .042) were significantly associated with the amount of third molar mesialization.

CONCLUSIONS

Greater third molar mesialization was observed when Nolla's stage of the third molar was higher before treatment and when the second molar protraction time was longer.

Relationship of Mandibular Ramus Dimensions to Lower Third Molar Impaction

Objectives The aim of this study was to investigate the mandibular ramus features that could contribute to the etiology of mandibular third molar impaction.

Materials and Methods Two hundred and forty subjects were divided into two groups: impacted group: 115 subjects presented with an impacted mandibular third molar, and control group: 125 subjects with the normal mandibular third molar eruption. Digital panoramic radiographs were used, and four angular and twelve linear measurements were done. Comparisons between groups were done using Student's t -test. Pearson correlation and linear regression tests were used to assess the degree of relationship between retromolar space and mandibular measurements.

Results Control group showed significant greater measurements in most of the variables, whereas the impacted group showed significant larger gonial angle and larger inclination of lower posterior teeth than the control group. Significant correlations were found between retromolar space and coronoid height, ramal heights, ramus notch depths, the inclination of lower posterior teeth, and retromolar space/3M width ratio in both groups.

Conclusion The present study found that the configuration of the mandibular ramus appears to be discrete in many aspects in the erupted other than impacted lower third molars subjects, which might be a possible cause for the impaction.

Transverse Changes in Mandible Following Bilateral Sagittal Split Ramus Osteotomy Advancement

Background

BSSRO is the most frequently performed surgical procedure for mandibular advancement. However, the effect of advancement on proximal segment is not clearly understood.

Aim and Objectives

The aim of the study was to evaluate the radiographic transverse changes in mandible following BSSRO advancement and to compare the amount of transverse displacement of the proximal segment with the amount of surgical advancement.

Materials and Methods

Twelve cases of skeletal class II deformity undergoing fixed orthodontic mechanotherapy and requiring mandibular advancement were selected for the study. Pre-operative (T0) PA ceph and OPG were used to measure the linear distances from right to left Co-Go, Go-Me, Go-Go, Co-Co, Rp-Rp and Co-Me points. The cases were operated for BSSRO mandibular advancement. Post-operative (T1) PA ceph and OPG were used to compare the changes in linear measurements.

Result

There were six male and six female patients with an average age of 19.5 years. The average mandibular advancement was 6.5 mm. Post-operative radiographic changes in transverse measurements of Go-Me, Go-Go, Co-Co, Rp-Rp and Co-Me were statistical significant. The changes in Co-Go measurements were statistically not significant. We could not establish any correlation between mandibular advancement and amount of transverse changes.

Conclusion

Significant changes were noticed in transverse dimensions of mandible following BSSRO advancement in both PA ceph and OPG. The transverse changes had no clinical implication during the post-operative follow-up.

Advanced biomaterials for repairing and reconstruction of mandibular defects

Mandibles are the largest and strongest bone in the human face and are often severely compromised by mandibular defects, compromising the quality of life of patients. Mandibular defects may result from trauma, inflammatory disease and benign or malignant tumours. The reconstruction of mandibular defect has been a research hotspot in oral and maxillofacial surgery. Although the principles and techniques of mandibular reconstruction have made great progress in recent years, the development of biomedical materials is still facing technical bottleneck, and new materials directly affect technological breakthroughs in this field. This paper reviews the current status of research and application of various biomaterials in mandibular defects and systematically elaborates different allogeneic biomaterial-based approaches. It is expected that various biomaterials, in combination with new technologies such as digital navigation and 3D printing, could be tuned to build new types of scaffold with more precise structure and components, addressing needs of surgery and post-reconstruction. With the illustration and systematization of different solutions, aims to inspire the development of reconstruction biomaterials.

Comparison of Orthopantomogram and Lateral Cephalogram for Mandibular Measurements

Aim:

The aim of the present study is to clarify the possible application of orthopantomogram (OPG) for evaluating craniofacial specifications such as angular and linear measurements of the mandible by comparing with lateral cephalogram.

Materials and Methods:

OPG and lateral cephalogram were taken from 100 patients of age group 16–35 years from Chettinad Dental College and Research Institute. Linear measurements (body length and ramus height) and angular measurement (gonial angle) were assessed both in lateral cephalogram and OPG. Independent t-test was performed for comparison of OPG and lateral cephalogram using SPSS with a probability level of P < 0.05 considered to be statistically significant.

Results:

The results of the present study show that there is no statistically significant difference in ramus height and gonial angle when compared between OPG and lateral cephalogram while statistically significant difference exists for body length between OPG and lateral cephalogram.

Conclusion:

It may be concluded that panoramic radiography can be used to determine the gonial angle and ramus height as accurately as a lateral cephalogram. However, clinicians should be vigilant when predicting horizontal measurement from OPGs.

An evaluation of panoramic radiograph to assess mandibular asymmetry as compared to posteroanterior cephalogram

Aim and Objectives

To assess the reliability of orthopantomograms (OPGs) in detecting facial asymmetry.

Materials and Methods

The OPGs and posteroanterior cephalograms for 10 patients with facial asymmetry were obtained from the outpatient department of the dental college. These radiographs were traced and analyzed. Six measurements (four linear and two angular measurements) were made on both sides. Asymmetry was defined by subtracting the right and the left side measurements. The differences from OPG were compared to those obtained from posteroanterior cephalograms. The kappa statistics and intra-class correlation coefficient (ICC) were used to calculate the differences.

Results

The ICC was calculated between OPGs and posteroanterior cephalograms difference measurements. The class interval for all measurements was noted between 0.61 and 0.84. The ICC was 0.7861, which shows strong correlation between the values (P < 0.0005) by probability 10−5, within 95%, coefficient correlation lies between 0.61 and 0.84. Kappa test gives a value of 0.64, which shows strong agreement between the measurements.

Conclusion

Individually, the measurements from OPGs may not be reliable but the obtained difference between the values of the OPGs and the posteroanterior cephalograms are comparable in nature and show strong correlation and can be used to detect facial asymmetry.

Morphological features of the mandible as predictors for neurosensory disturbances after bilateral sagittal split osteotomy

This retrospective study aimed to identify anatomical predictors of neurosensory disturbance (NSD) after bilateral sagittal split ramus osteotomy (BSSO) by evaluating the morphology of the mandible on lateral cephalograms (LCs) and orthopantomograms (OPTs). The LCs and OPTs of 142 patients who underwent BSSO were reviewed. The influence of the mandibular angle was assessed on LCs, while the following morphological landmarks and subsequent measurements were analysed on OPTs: vertical and horizontal positions of the lingula, ramus width, mandibular body height, mandibular canal position and mandibular angle length. Post-operative NSD (hypoaesthesia) was considered permanent when objective tests or subjective evaluations indicated altered sensation one year after BSSO. Generalised linear mixed models were used to take into account the repeated measurement design (left and right measurements within one patient). Hypoaesthesia was present in 10.6% of the patients (5.6% of sites). After adjusting for age, a small mandibular body height was found to significantly increase the risk of hypoaesthesia. The other measurements showed no significant association with hypoaesthesia. These findings show a relationship between mandibular morphology and hypoaesthesia after BSSO and can aid surgeons in pre-operative assessments of the risk of NSD. Further research is needed to identify risk factors for NSD based on mandibular morphology.

Comparison of gonial angle determination from cephalograms and orthopantomogram

Introduction:

Gonial angle is an important parameter of the craniofacial complex giving an indication about the vertical parameters and symmetry of the facial skeleton. Both orthopantomogram (OPG) and lateral cephalograms can be used for the measurement of gonial angle. Because of the superimpositions seen on lateral cephalograms, reliable measurement of the gonial angle becomes difficult. The aim of the present study is to check the possible application and reliability of OPG for gonial angle determination by clarifying whether there is any significant difference between the determination of gonial angle from OPG and cephalogram.

Materials and Methods:

Gonial angle measurements were made on lateral cephalograms and orthopantomograms of 98 patients - 44 males (mean age 25.9 years) and 54 females (mean age 21.3 years), and compared using Statistical Package for Social Sciences.

Results:

One-way analysis of variance demonstrated no significant differences between the values of gonial angles determined by lateral cephalogram and panoramic radiography. Pearson correlation showed a high correlation between cephalometric and OPG gonial angle value.

Conclusion:

Panoramic radiography can be used to determine the gonial angle as accurately as a lateral cephalogram. For determination of the gonial angle, an OPG may be a better choice than a lateral cephalogram as there are no interferences due to superimposed images of anatomical structures as in a lateral cephalogram. Thus, the present study substantiates the possibility of enhancing the clinical versatility of the panoramic radiograph, which is an indispensable tool for dental diagnosis.

Styloid process elongation and calcification in subjects with tmd: clinical and radiographic aspects

Knowledge of the Eagle's syndrome shows that its symptoms can be very easily confused with other types of craniomandibular disorders, especially temporomandibular disorders (TMD). The aim of this study was to find a possible correlation between the presence of TMD and elongation of the styloid process as well relate to presence of calcification of the stilohyoid chain. Fifty patients with TMD, confirmed from the RDC/TMD, were examined clinically and radiographically. Radiographic documentation consisted of digital panoramic radiograph and digital lateral cephalometric radiograph. Radiocef software (Radiomemory) was used for the analysis of radiographs by means of specific cephalometric tracing and linear measurements of the styloid process. Each radiograph was traced and measured three times with intervals of 1 month to spread the error. Statistical analysis was performed by Pearson's test (p=0.001) using Biostat 4.0 statistical software. Result showed an incidence of 76% elongation of the styloid process in the sample. There was a correlation between the bilateral measures taken in panoramic radiographs (?<0.001) and also for measures of styloid process length carried out in different panoramic radiographs and lateral cephalometric radiographs (?<0.001). It was concluded that there is prevalence of elongated styloid process in patients with TMD. However, no relationship was found between measurements on the stylohyoid chain and symptoms of headache, orofacial pain, tinnitus and vertigo.

The velic traverse: an independent oral articulator?

Two speech functions have traditionally been ascribed to the velum: opening and closing the velopharyngeal port and providing a passive surface against which the tongue can produce oral constrictions. Contrary to this passive oral function, the present x-ray study finds that a substantial portion of the velum moves to constrict the oropharyngeal isthmus for French uvular /ʁ/. This substructure, designated the velic traverse, functions independently of the parts of the velum used for velopharyngeal port closure, thus acting as an oral articulator. An active velic traverse challenges methods for estimating vocal tract shapes based on tongue posture alone.

Anterior and medial angulations of the styloid process in subjects with TMD: clinical and radiographic findings

This study investigated the existence of association between the angulation of the styloid process on the anterior and medial directions with the intensity of temporomandibular dysfunction (TMD) symptoms. Fifty patients (8 men and 42 women) aged 25 to 70 years, with relevant TMD symptoms were evaluated. Clinical examinations were performed to determine the severity of TMD symptoms (orofacial pain, headache, tinnitus and dizziness) based on the RDC/TMD criteria and the visual analogue scale (VAS), and digital radiographic images of the styloid process were obtained: lateral cephalometric skull radiograph (analysis of anterior angulation) and posteroanterior skull radiograph (reverse Towne's projection) (analysis of medial angulation). The anterior angulation average of the styloid process was 20.89° while the medial angulation average was 19.1° in the right side and 19.04° in the left side. There was no statistically significant difference among the patient groups (severe, moderate and mild symptoms) associating the TMD symptoms and the anterior or medial angulation of the styloid process (p>0.05). There was no correlation between the intensity of the TMD symptoms and the measurements of anterior and medial angulation of the styloid process using either lateral cephalometric or posteroanterior radiographs (reverse Towne's projection).

Influence of the intergonial distance on image distortion in panoramic radiographs

OBJECTIVES

The aim of this study was to evaluate the influence of the intergonial distance during the formation of panoramic radiographic images by means of horizontal and vertical measurements.

METHODS

30 macerated mandibles were categorized into 3 different groups (n = 10) according to their intergonial distances as follows: G1, mean distance 8.2 cm, G2, mean distance 9.0 cm and G3, mean distance 9.6 cm. Three metal spheres 0.198 cm in diameter and placed at an incline using an isosceles triangle were separately placed over the internal and external surfaces of the mandibles before radiographic exposure for the purpose of taking the horizontal and vertical measurements. The occlusal planes of the mandibles were horizontally placed on the chin rest of the panoramic machine Orthopantomograph® OP 100 (Instrumentarium Imaging, Tuusula, Finland) and were then radiographed. In the panoramic radiographs, an expert radiologist measured the distances between the metal spheres in the horizontal and vertical directions using a digital caliper. The data were tabled and statistically analysed by Student's t-test and analysis of variance with Tukey post-test (α = 0.05).

RESULTS

In all three groups magnification of the distances between spheres was observed when compared with the real distance in both horizontal and vertical measurements (p < 0.05). Differences in both horizontal and vertical measurements were observed between the different regions (p < 0.05), however there were no differences between groups in the same region (p > 0.05). Differences between horizontal and vertical measurements were observed in different regions in all evaluated groups (p < 0.05).

CONCLUSION

The intergonial distance is a factor that had no influence on image formation in the panoramic radiograph.

Reliability of computational measurement of the condyles on digital panoramic radiographs

OBJECTIVE

The aim of this study was to evaluate the reliability of a computational method for assessing three condylar measurements on digital panoramic radiographs: condylar height, area and perimeter.

METHODS

A computer calculation of the area, the perimeter and the height of 34 condyles was determined on digital panoramic radiographs taken from 17 patients. The test-retest precision of measurements calculation was estimated using an intraclass correlation coefficient (ICC) and Dahlberg's formula at 2 week intervals on the same radiograph to assess intraobserver precision and on two radiographs (RX1 and RX2) to assess the radiographic procedure precision. Changes between measurements on RX1 and RX2 were estimated using paired t-tests to detect systematic errors.

RESULTS

Precision of all indices was very high when measurements were made on the same radiograph, thus confirming good reliability for the present computational measuring method. The precision was lower when two different radiographs were compared but was still within an acceptable range of tolerance. There were no statistically significant changes in condylar area, perimeter or height values between RX1 and RX2.

CONCLUSIONS

This study has demonstrated that (1) the height of the condyle can be rapidly and reliably assessed using a specific computer system directly on digital panoramic radiographs; (2) although less reliable, area and perimeter can also be acceptably evaluated; and (3) this method has the potential for being routinely used to monitor changes in clinical follow-up as well as for research purposes.

Evaluation of the panoramic image formation in different anatomic positions

The aim of this study was to determine size, shape and position of the image layer by evaluation of the radiographic image formation in different anatomic positions. A customized phantom was made of a rectangular acrylic plate measuring 14 cm² and 0.3 cm thick, with holes spaced 0.5 cm away and arranged in rows and columns. Each column was separately filled with 0.315 cm diameter metal spheres to acquire panoramic radiographs using the Orthopantomograph OP 100 unit. The customized phantom was placed on the mental support of the device, with its top surface kept parallel to the horizontal plane, and was radiographed at three different heights from the horizontal plane, i.e., the orbital, occlusal and mandibular symphysis levels. The images of the spheres were measured using a digital caliper to locate the image layer. The recorded data were analyzed statistically by the Student'-t test, ANOVA and Tukey' test (?=0.05). When the image size of spheres in horizontal and vertical axes were compared, statistically significant differences (p<0.05) were observed in all areas, portions of the image layer and heights of horizontal plane evaluated. In the middle portion of the image layer, differences in the image size of spheres were observed only along the horizontal axis (p<0.05), whereas no differences were observed along the vertical axis (p>0.05). The methodology used in this determined the precise size, shape and position of the image layer and differences in magnification were observed in both the horizontal and vertical axes.

True hemifacial microsomia and hemimandibular hypoplasia with condylar-coronoid collapse: diagnostic and prognostic differences

INTRODUCTION

Long-term results after orthopedic or surgical treatment of hemifacial microsomia (HFM) have shown a tendency toward recurrence of the facial asymmetry. However, the literature contains a number of successful case reports that show surprising changes in the morphology of the condyles. In addition, patients with similar mandibular asymmetries, treated early with surgery, have excellent long-term follow-ups, especially those who have little or no soft-tissue involvement, but only severe mandibular ramal deformities. The phenotypes of these cases are unexpectedly similar, with a consistent collapse of the condyle against the coronoid and a deep sigmoid notch. The objectives of this article were to help distinguish true HFM from this peculiar type of hemimandibular asymmetry morphologically and to quantify their differences before treatement and in the long term.

METHODS

Panoramic radiographs taken at pretreatment and the long-term follow-up of 9 patients with hemimandibular hypoplasia, characterized by the collapse of the condyle against the coronoid, were compared with those of 8 patients with severe type I and type II HFM; these records were collected before and at least 10 years after distraction osteogenesis.

RESULTS

Ratios and angular measurements before and after treatment differed significantly between the 2 groups.

CONCLUSIONS

Perhaps these patients were misdiagnosed and actually had secondary injuries of the condyle, which have a normal functional matrix. Therefore, with growth and functional stimulation, they would tend to grow toward the original symmetry. To make a differential diagnosis between true HFM and this peculiar type of hemimandibular hypoplasia, the collaboration between not only orthodontists and surgeons, but also geneticists and dysmorphologists, is of great importance because of the different prognoses.

Comparison of mandibular vertical growth in hemifacial microsomia patients treated with early distraction or not treated: follow up till the completion of growth

AIM

Comparison of the long-term follow-up until the completion of growth of two homogeneous samples of children affected by hemifacial microsomia (HFM), one treated by mandibular distraction osteogenesis (DO) in the deciduous or early mixed dentition, the other not subjected to any treatment until adulthood.

MATERIAL

Fourteen patients affected by vertically severe type I or II HFM were operated at an average age of 5.9 years with an average follow-up of 11.2 years. They were compared to a sample of eight patients who were never treated until the completion of growth.

METHODS

Mandibular vertical changes were measured on panoramic radiographs taken at different time points. Ratios between affected and non affected ramal heights were calculated and compared.

RESULTS

In the DO sample, after correction, mandibular vertical changes showed a gradual return of the asymmetry with growth in all patients. The ratio in the non treated sample was unchanged between the initial and the long term panoramic x-rays.

CONCLUSION

The facial proportions of HFM patients are maintained, when not treated, throughout growth. The same proportions return to their original asymmetry after DO. Even though short term aesthetic and psychological advantages of distraction osteogenesis are well accepted, early surgery should only be applied after careful patient selection and honest clarification of the long term recurrence by genetically guided craniofacial growth pattern.

Reliability of panoramic radiographs for the assessment of mandibular elongation after distraction osteogenesis procedures

To determine whether panoramic radiographs could be used for evaluation of changes in the vertical and horizontal dimensions following internal curvilinear mandibular distraction osteogenesis.

STUDY DESIGN

A retrospective cohort study included 25 patients who underwent bilateral mandibular distraction surgery. Three panoramic radiographs and lateral cephalograms from each patient were available: before distraction, immediately upon termination of the distraction process, and at the end of the follow-up period. The radiographs were traced by plotting Condylion, Gonion, and Menton. The linear distances between Condylion and Gonion and between Gonion and Menton were measured on each side, and the correlation was calculated.

RESULTS

No significant differences were found between the values of the linear measurements determined by lateral cephalograms and panoramic radiographs (p ≥ 0.079), excluding one measurement. The correlation test for these radiographs showed very high, positive and statistically significant correlations, for both sides of the internal mandibular distraction (r > 0.77, p ≤ 0.0001), apart from three measurements.

CONCLUSION

Panoramic radiographs, with mandibular length (Co-Go and Go-Me) measurements, can be used as an alternative to lateral cephalograms, i.e. as a reliable tool for assessing vertical and horizontal dimensional changes resulting from internal mandibular distraction achieved by a curvilinear distractor.