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Thirty 3-week-old male Wistar rats were grouped into a hard diet control group, a kneaded-diet group, and a powdered-diet group. After 6 weeks of growth, all rats were killed under deep anesthesia. The effects of dietary physical consistency on the mandible were investigated with respect to morphology and bone mineral content using lateral cephalometric analysis and computed X-ray densitometry. Significant differences between the experimental and control groups were determined by measuring the means and standard deviation of the coordinates and differences between 15 points selected on the mandibles. Gonion (Go), which is a measurement of depth to the X-axis, was significantly less in the powdered-diet group, while the kneaded-diet group showed no significant differences. The most posterior point of the coronoid process (Cr) and the most posterior point of condylar process (Cd), which are measures of height to the Y-axis, were less in the kneaded-diet group than in the control group. In the powdered-diet group, Cr, Cd, Go and Infradentale were significantly less than in the control group. On the other hand, the bone mineral content was significantly lower in the coronoid process and angle of mandible in only the powdered-diet group.

Adenomatoid odontogenic tumor is a rare benign and odontogenic tumor that is frequently misdiagnosed as other odontogenic cysts and tumors on radiographic examination. To acquire additional information of adenomatoid odontogenic tumor, we performed magnetic resonance imagings (MRI) at a case of adenomatoid odontogenic tumor. The lesion was divided between the peripheral portion with a thick circular shape and the central portion with a round shape on the basis of the signal intensity (SI) of MRI. The peripheral portion showed intermediate SI contained multifocal no SI on T1WI, high SI contained multifocal no SI on T2WI, and heterogeneous enhancement on CE-T1WI. These multifocal areas corresponded to the numerous punctate radiopaque foci shown on computed tomography. The central portion showed homogeneous low SI on T1WI, homogeneous very high SI on T2WI, and no enhancement on CE-T1WI. Macroscopic examination revealed the round shaped lesion included one large cystic space correspondent to the central portion with a clear cystic wall correspondent to the peripheral portion on MRI. The MRI features corresponded to the macroscopic findings of the histopathological examination.

Objectives: To assess the appearance, location, and course of the incisive canal as compared to other anatomical landmarks on spiral CT of the mandible., Methods: Study material included 230 spiral CT scans taken for preoperative planning of implant placement in the posterior mandible. All scanning was performed using a standard exposure and patient positioning protocol. Axial, panoramic, and reformatted cross-sectional images were carefully examined. Visibility of the incisive canal and other anatomical landmarks was scored using a four-point rating scale. The vertical and buccolingual diameter of the outer contour as well the diameter of the inner contour of the incisive canal were measured using a digital sliding caliper., Results: An incisive canal was identified in 93% of the cases, with good visibility in 22% of the cases. Mean (s.d.) vertical diameter, buccolingual diameter, and inner diameter of the incisive canal were 4.7 (1.1), 3.7 (0.7), and 1.1 (0.3) mm respectively. The mandibular canal, mental foramen, lingual foramen, and anterior looping appeared in 98, 100, 82 and 7% of the images respectively., Conclusions: A well-defined incisive canal could be detected in the majority of spiral CT scans. Its radiographic detection remained lower than for the mandibular canal or mental foramen, but higher than for the visibility of the lingual foramen. Visualisation of the incisive canal and the occasional presence of an anterior looping, demonstrates the potential value of cross-sectional imaging of the anterior mandible for presurgical planning purposes.

Objectives: To determine the precision and accuracy of three-dimensional (3D) volume rendering spiral multislice computed tomography (CT)-based linear measurements of the mental foramen for dental implants, in vitro, and their precision, in vivo., Methods: Five cadaver heads were imaged by multislice spiral CT (Toshiba Aquilion) with 0.5 mm thick axial slices (0.5 mm/0.5 s of table feed) at 0.5 mm interval reconstructions. The image data sets were transferred to a networked computer workstation. Using computer graphics the data were analysed with a 3D volume rendering technique using Vitrea software. Two oral and maxillofacial radiologists, independently, made electronic linear measurements from the superior border of the mental foramen to the crest of the alveolar process. The soft tissues were removed and physical measurements made using a 3 Space (Polhemus, Colchester, VT, USA) electromagnetic digitizer with a personal computer running Windows 98. The same linear measurements of 15 patients using the same imaging methodology were performed and the precision was analysed., Results: The findings showed no statistically significant inter- or intra-observer differences in vitro and in vivo, or between imaging and physical measurements in vitro (P>0.05)., Conclusions: 3D multislice spiral CT imaging allows highly accurate measurements for dental implant placement in proximity to the mental foramen. Computer graphics software, using volume rendering is suitable for implant planning.

We describe two cases of Class III malocclusion with and without orthodontic treatment. A thin-plate spline (TPS) analysis of lateral cephalometric radiographs was used to visualize transformations of the mandible. The actual sites of mandibular skeletal change are not detectable with conventional cephalometric analysis. These case analyses indicate that specific patterns of mandibular transformation are associated with Class III malocclusion with or without orthopaedic therapy, and visualization of these deformations is feasible using TPS graphical analysis.

The chin is a very common donor site for autogenous bone grafts. The aim of this retrospective study was to evaluate long-term morbidity of the donor site following chin bone graft harvesting. One to three years after grafting of local bone defects of the anterior maxilla with chin bone, 21 patients were recalled for objective assessment of any residual morbidity at the harvesting area. Morbidity as well as satisfaction of the patients were evaluated by a survey of the medical record, a mail-in questionnaire, and a standardized physical examination. The outcome of this study showed that there was good acceptance of the chin bone harvesting procedure. The objective morbidity was low, but subjectively almost half of the patients reported a changed (decreased) sensibility in the harvesting area. This subjective change in sensibility did not result in noteworthy complaints or discomfort by the patients, however. Although bone harvesting from the chin is generally considered as a good option for reconstruction of local bony defects, the patients should be informed about the potential hazard of a changed sensibility in the chin region.

The purpose of this study was to compare positional changes of the hyoid bone and the amount of postsurgical compensation in mandibular position in patients who received either wire or rigid fixation after surgery. Data were analyzed from 97 patients (25 males and 72 females) who were randomized to receive wire (43) or rigid (54) fixation after mandibular advancement surgery as part of a multicenter clinical trial. Radiographs were digitized before surgery (T2), immediately after surgery (T3), and 8 weeks (T4), 6 months (T5), 1 year (T6), and 2 years (T7) after surgery. The wire group had greater sagittal relapse of the hyoid bone at T6 (P =.007), which persisted at T7 (P =.02). Both groups showed upward movement of the hyoid bone after surgery. There was no relationship between the vertical change in the the hyoid bone position and the vertical position of mandible (B point y coordinate, mandibular plane). However, there was a relationship between the horizontal hyoid bone position and B point during the postsurgical period (rigid, r = 0.450; wire, r = 0.517). The direct distance from the hyoid bone to basion increased (P <.001) in both groups at T3 and then recovered its original length after 8 weeks (P <.001). The rigid group showed no significant change in distance from the hyoid to the genial tubercles, but the wire group showed recovery of the muscle length at T6 (P <.05) and T7 (P <.05).

Despite personal preferences and training background that may influence the choice of which genioplasty technique to use, the osteoplastic technique has a better patient satisfaction rate (albeit slight), better soft tissue predictability, and less detrimental postoperative complications when compared with alloplastic augmentation of the chin. In addition, the osteoplastic technique is a more versatile procedure that can be used to correct any type of chin deformity and it has less of the limitations and contraindications associated with the alloplastic techniques.

This study sought to characterize the anatomical dimensions of the anterior mental loop and to determine the accuracy of conventional radiographs in identifying its presence and dimensions. The study group consisted of 46 hemimandibles fixed in formalin. Radiographs of the area between the mental foramen and the midline were obtained and evaluated for each hemimandible, followed by dissection and physical examination of the same area. Anatomically, an anterior loop of the mental nerve was observed in only 13 hemimandibles (28%). The anterior extension of the loop ranged from 0.4 to 2.19 mm. No correlation was found between the radiographic image and the anatomical shape of the loop. Of the radiographically diagnosed loops, 40% were not seen in anatomical examination. In cases with a false radiologic loop, a correlation was found between the diameter of the origin of the incisive canal and the radiologic interpretation of the loop. The radiologic appearance or diagnosis of the anterior mental loop in cadaver mandibles does not disclose the true ramification of the inferior alveolar nerve to the mental and incisive nerve.

Purpose: This study investigated the relationship of age at surgery and type of fixation to the pattern and extent of bone remodeling associated with inferior border osteotomy for chin augmentation., Patients and Methods: Four groups of patients with similar chin advancement were established by age at the time of surgery: younger than 15, 15 to 19, 20 to 24, and older than 39 years. Cephalometric radiographs for immediate preoperative, immediate postoperative, and at least 9 months postoperative times were traced, digitized, and superimposed., Results: The pattern of osseous remodeling was similar for all age-groups. This consisted of resorption of the superior-buccal aspect of the distal segment, bone apposition on the buccal surface of the proximal segment, and modest resorption at pogonion (mean change, 1 mm or less). There was no significant difference in stability of the chin advancement between wire and rigid (screw) fixation. There was a marked difference in the symphysis thickness regeneration of the youngest group (92% of the original symphysis thickness) compared with the rest of the groups (< or =66%, P < .001)., Conclusions: Minimal remodeling at pogonion occurs in all age-groups with both wire and rigid fixation. Regeneration of symphysis thickness is much more complete in patients younger than 15 years at the time of surgery. This is potentially important for early treatment of severe chin deficiency, because it permits additional advancement of the chin later in life, if necessary.

Objective: The present study was undertaken to document whether mandibular length could be increased by distraction osteogenesis in children and what happens to the mandibular position 1 year after the distraction., Methods: Five patients with hemifacial microsomia (four unilateral, one bilateral) had distraction osteogenesis performed to lengthen the mandible. All patients had cephalometric and panoramic radiographs obtained before and 3, 6, and 12 months after the distraction osteogenesis., Results: The total mandibular length (Co-Gn) on the affected side was increased by 11.2 mm after the distraction and remained stable during a 1-year observation period. However, the increased mandibular length tended to move the chin downward (8 mm) more than forward (2 mm) during the same period., Conclusions: Distraction osteogensis can be used to lengthen the hypoplastic mandible. However, most of the increased mandibular length moved the chin downward more than forward.

The radiological study by panoramic and CT scan methods of the Neanderthal La Chapelle-aux-Saints mandible shows us that the mandibular canal very closely resembles that which we can see in modern man. The images obtained are of good quality and can be utilized for the analysis of the internal structure of fossils.

Objectives: To determine the most common position of the mental foramen in a selected Saudi population and to compare the results with those reported for other populations., Methods: Four hundred and fourteen panoramic radiographs of a Saudi population from four different dental centres were studied., Results: The commonest position of the mental foramen was in line with the longitudinal axis of the second premolar (45.3%) followed closely by location between the first and second premolars (42.7%). The mental foramen was symmetrical in 80% of patients., Conclusion: Clinicians should expect to find the position of the mental foramen to be symmetrical and in line with the second premolar teeth.

Thrombosed varix in the oral region often appears as a pigmented mass in the mucosa simulating a hemangiomatous lesion. It rarely occurs in the deeper orofacial region. We report a case of thrombosed varix in the submandibular space with symptoms of a tumor. The clinical symptoms and MRI and CT findings are discussed. The clinical symptoms were not characteristics. High signal intensity on CT (80 HU) and a concentric signal distribution on CT and MRI may suggest a thrombosed varix.

Background: The great diffusion of the surgical technics in oral implantology and the progress of the radiological imaging produces some interest for the clinical anatomy of the mental foramen (MF). The study, in addition to the measurements that define it, considers others anatomical features of practical utility and the variableness of them., Methods: In the Anatomic Institute of the Bologna University, it has been made a morphometric revision of the MF on 100 dried mandibles of normal young adults (78 males, 32 females) random chosen with the complete integrity of the dental apparatus and of the mandibular bone criteria. The measurements have been made by anthropometric methods on the two sides of the same mandible (n = 200) and for everyone has been reported in the tables the medium, the maximum and the minimum values with their specific variation interval. The results are applicable to the common work conditions because they take in consideration among the specific characteristics of the MF in addition to the seat, the course of the mandibular canal, the thickness and the height of the mandibular bone., Results: To the clinical and diagnostic imaging object the medium values of the anatomical measurements can be considered sufficent. To anthropometric, anesthesiologic and surgical aims it is also necessary the knowledge of the maximum and the minimum values and the variation interval. In the living man the anatomicomedical study of the MF is made by the diagnostic imaging, especially by computed tomography with specific algorithm, because it makes possible absolutely exact measurements., Conclusions: Finally, the specifications on the MF provided by the present study are important not only for an anatomical but also for a practical point of view because they are a datum point value in the patient clinical management.

Three-dimensional models created by milling machines and stereolithography from the three-dimensional computed tomograms (CTs) have become important in the diagnosis and preoperative planning of some craniomaxillofacial irregularities. In this study three-dimensional milled models were used to verify operative results after patients had undergone bilateral sagittal split osteotomies of the mandible. Fifteen models of patients with mandibular prognathism and 31 with retrognathism were created preoperatively and 6 weeks postoperatively to examine the changes of the osseous anatomical structures in three dimensions. There was a forward shift in the mandibular corpus of between 1 and 3 mm in patients with retrognathism and a backward shift to the same extent in the group with prognathism. In the latter group the intercondylar distance increased by a mean of 2.0 (SD 1.2) mm and by 2.9 (SD 1.0) mm in patients who had had a mandibular advancement operation. Furthermore the distance between the coronoid processes increased by 6.6 (SD 1.8) mm in the retrognathic group and decreased by 1.6 (SD 1.4) mm in the prognathic group. The Bonewill angle increased by 1.7 (SD 0.4) degrees in the prognathic group and decreased by 1.6 (SD 0.3) degrees in the retrognathic group. Both increase and decrease of the homolateral gonion angle were accompanied by a contrarotary movement of the contralateral gonion angle. We conclude that remarkable changes in condylar position and anatomy take place after bilateral ramus sagittal split osteotomy.

Purpose: This study assessed the soft tissue changes produced by the placement of hard tissue replacement (HTR) polymer chin implants for augmentation genioplasty and evaluated the dimensional stability as well as any bony changes associated with the implants., Patients and Methods: The study group consisted of 18 patients (3 males, 15 females) with an average follow-up of 21.5 months (range, 12 to 44 months). All implants were placed through an intraoral incision and stabilized to the symphysis with a single 2.0-mm diameter titanium screw. Preoperative, postoperative, and long-term cephalometric radiographs were analyzed for changes in soft tissue thickness in the chin region, implant stability, and the presence of bone resorption., Results: The net hard tissue chin augmentation achieved averaged 6.0 mm (range, 4.5 to 9 mm). Average preoperative soft tissue thickness was 12.1 mm (range, 11 to 14.5 mm) and postoperatively it was 10.6 mm (range, 10 to 13.5 mm). The average increase in soft tissue projection was 77.6% (range, 71.4% to 83.3%) of the implant thickness. There was no radiographic evidence of implant migration or bony resorption beneath the implant., Conclusions: HTR implants appear to be a predictable means of augmenting the chin, providing the desired aesthetic change, without causing resorption of underlying bone.

The aim of this investigation was to examine and compare the validity of Björk's and Ricketts' methods for the superimposition of serial cephalometric radiographs of the mandible for the analysis of changes over the duration of routine orthodontic treatment in growing subjects (approximately 2 years). Pre- and posttreatment lateral cephalometric radiographs of 23 children, with tantalum markers implanted in the mandible, were studied. The differences in position of six dental and skeletal landmarks between superimposition on Björk's structures and on Ricketts' corpus axis were compared with those on the basis of the implants. A rotational effect was found for corpus axis resulting from differential movement of Xi point with growth, whereas Björk's method yielded results essentially similar to those of the implant-based superimposition. This resulted in statistically significant median differences between the two methods for all landmarks except pogonion and menton. The magnitude of the differences increased with distance from the central core of the mandible and were generally greater horizontally than vertically. Although most differences were less than 2 mm, approximately 10% of the subjects showed differences greater than 4 mm for molar and incisor landmarks. These findings suggest that, for growing subjects, Björk's method should be preferred Ricketts', which cannot be relied on to indicate the true (intramandibular) changes during orthodontic treatment in growing subjects.

The effects of various directed forces applied by combined headgear were evaluated in this study. The study material consisted of 30 patients with Class II dental relationships and steep mandibular plane angles. Three groups of 10 patients each were formed. In the first treatment group, forces of 150 gm per side were used for the high-pull component and the cervical component. In the second treatment group, forces of 200 gm per side for the high-pull component and 100 gm per side for the cervical component were applied. In the third treatment group, forces of 100 gm per side were applied for the high-pull component and 200 gm per side for the cervical component. Distal tipping of upper molar was greatest in the third treatment group. Intrusion of the upper molar in the second treatment group and extrusion of the upper molar in the third treatment group were statistically significant. Changes in occlusal and mandibular plane angles showed significant differences between the groups.

The aim of this randomized, controlled, prospective study was to determine the reliability of computed lateral cephalometry (Fuji Medical Systems, Tokyo, Japan) in terms of landmark identification compared to conventional lateral cephalometry (CAWO, Schrobenhausen, Germany). To assess the reliability of landmark identification on lateral cephalographs, 20 computed images, taken at 30 per cent reduced radiation (70 kV, 15 mA, 0.35 s) were compared to 20 conventional images (70 kV, 15 mA, 0.5 s). The 40 lateral cephalographs were taken from 20 orthodontic patients at immediate post-treatment and 1 year after retention. The order and type of imaging was randomized. Five orthodontists identified eight skeletal, four dental and five soft tissue landmarks on each of the 40 films. The error of identification was analysed in the XY Cartesian co-ordinate following digitization. Skeletal landmarks exhibited characteristic dispersion with respect to the Cartesian co-ordinates. Root apices were more variable than crown tips. Soft tissue landmarks were more consistent in the X co-ordinate. Two-way ANOVA shows that there is no significant difference between the two imaging systems in both co-ordinates (P > 0.05). Moreover, the differences are generally small (< 0.5 mm), and are unlikely to be of clinical significance. Most of the variables attained statistical power of at least 0.8 in the X-co-ordinate while only the dental landmarks achieved statistical power of at least 0.78 in the Y-co-ordinate. Based on the results of the study: (1) computed lateral cephalographs can be taken at 30 per cent radiation reduction, compared to conventional lateral cephalograph; (2) each anatomical landmark exhibits its characteristic dispersion of error in both the Cartesian co-ordinates; (3) there is no trend between the two imaging systems, with equivocal result, and none of the landmarks attained statistical significance when both raters and imaging systems are considered as factorial variables; (4) the random error of raters in landmark identification after replicate tracing was highlighted and needs to be taken into consideration in all studies involving landmark identification.

Objective: To compare the skeletal stability of wire and screw fixation after advancement genioplasty., Design: Retrospective study., Setting: Teaching hospital and private practice, South Africa., Subjects: 40 Patients who required advancement genioplasty, 20 in each group., Interventions: Advancement genioplasty measurements made on cephalometric radiographs before and immediately after operation, and at least 6 months later., Main Outcome Measures: Comparison of horizontal and vertical measurements., Results: In the screw (rigid) group mean horizontal advancement was 6.3 mm followed by a relapse of 0.3 mm during the follow up period. The corresponding figures for the wire (non-rigid) group were 5.8 and 0.5 mm. The two differed significantly in the degree of vertical change but the result is clinically unimportant. There was no difference in the degree of horizontal change., Conclusion: There was no difference in skeletal stability between the two groups.

Objective: The purpose of this study was to retrospectively investigate mandibular asymmetry in unilateral cleft lip and palate individuals (UCLP) in relation to chronologic age and in relation to lower facial asymmetry., Design: The longitudinal records of 34 UCLP individuals and 142 controls treated in the Department of Orthodontics, Eastman Dental Center, Rochester, NY, were included in the study. Posteroanterior and oblique cephalometric radiographs were analyzed for lower facial asymmetry and mandibular asymmetry, respectively. Mandibular asymmetry in UCLP was analyzed relative to three age groups (6-10, 11-14, and 15 or greater) and compared to controls. Moreover, mandibular asymmetry was analyzed relative to lower facial asymmetry., Results: UCLP individuals showed no significant differences in mandibular asymmetry compared to controls. In addition, no significant correlation was found between mandibular asymmetry and lower facial asymmetry in UCLP., Conclusions: The degree of mandibular asymmetry in UCLP appears not to be the major contributing factor to the lower facial asymmetry noted on these individuals. Possible cranial-base/temporal-region anomalies may be involved in unilateral cleft lip and palate and be responsible of the asymmetry noted in the lower facial skeleton.

The present study evaluated how 2 widely used cephalometric sagittal analyses, ANB angle and WITS appraisal, classify skeletal classes I, II, and III in a random selection of 497 Finnish boys aged 4-20 years. This distribution was also compared with the visual inspection of cephalometric structures judged by 2 university instructors in orthodontics. The results showed remarkable differences and even sparked controversy concerning classification of the sagittal jaw relationships. The ANB angle and the WITS appraisal emphasized the role of class II based on a failure to distinguish the proportion of class I. The low-angle influence skewed the distribution of the ANB pattern in the class III direction, and the WITS pattern, conversely, towards class II. High- or low-angle influence had only minor effects on the visual inspection of cephalometric structures. This cross-sectional study showed an age-related decreasing mean value for the ANB angle and increasing mean value for the WITS appraisal, thus explaining the remarkable difference in the distribution of sagittal classes. However, the findings of age-related changes makes the use of the fixed norms questionable. For extreme or controversial cephalometric interpretations, visual inspection provides an essential aid in diagnosis and skeletal classification.

A study was conducted to evaluate the relationship between morphological characteristics of vertical sections of the mandibular body and dentopfacial morphology. Cortical bone thickness, tooth inclination and bone inclination of the mandible were investigated. Among skeletal components, ANSMe distance was associated with the buccal cortical bone thickness of the P2 (second premolar) section. Gonial angle, SN to mandibular angle, and palatal to mandibular angle were negatively correlated with the buccal cortical bone thickness of P2 and M1 (first molar) sections. SNA and SNB which indicated the protrusion of the upper and lower jaws were positively correlated with the buccal cortical bone thickness of the M1 section. Among denture components, lower and upper incisor positions showed a significant negative correlation with the buccal cortical bone thickness of the P2 section. The interincisal angle was associated with the basal cortical bone thickness of the M2 (second molar) section. In summary, there were significant and complex relationships between the structures of the mandibular body and maxillofacial morphology. Facial types which relate to masticatory function are associated with the cortical bone thickness of the mandibular body.

Sonographic imaging of the fetal face is important because a number of chromosomal aberrations are associated with facial malformations. Prenatal diagnosis of abnormalities of the fetal chin and lips have been based on subjective assessment. The purpose of the current study was to establish normative dimensions for the objective assessment of the fetal face. A cross-sectional study was performed in 200 normal healthy singleton pregnancies between 16 and 38 weeks' gestation. Inclusion criteria included performance of a first or early second-trimester scan to confirm gestational age (GA). Exclusion criteria included birth weight < 10th or > 90th percentile for GA, and medical complications of pregnancy. Ultrasound measurements were made in the mid-sagittal plane and included chin length (CL) and upper lip width (ULW). A first-degree linear growth function was observed throughout pregnancy between GA and ULW (r = 0.87) and CL (r = 0.91). All measured data are expressed as mean +/- 2 SD. In conclusion, these results provide normative dimensions throughout gestation for the fetal upper lip and chin. These data are expected to serve as a basis for the objective assessment of the fetal face in high-risk conditions.

The aim of the present investigation was to determine the relative extent of geometric error and errors in point identification in postero-anterior roentgenography. In one series of tests a group of dry human skulls was used, and the same cephalometric landmarks were identified twice by two orthodontists, using postero-anterior roentgenographs, first using the dry skulls as such, and then the same skulls with metal markers inserted to show the exact locations of the cephalometric points. Consistency and normal variation in the reproducibility of head position in the cephalostat between repeated roentgenographs were studied by a photographic technique in a group of young healthy adults, measuring the extent of minor head movements. Geometric error was calculated using a computer-aided design program (CAD) by rotating the three-dimensional co-ordinates of the cephalometric landmarks and thus obtaining projection error in the frontal view. Accuracy in cephalometric point identification was best in dental landmarks and vertical orientation of superior orbital margins. Geometric error was least when landmarks near the anterior midsagittal plane, such as upper and lower dental midlines or point gonion were compared with each other. Width measurements from frontal-view cephalograms are most sensitive to minor movements in head posture. Due to combined errors, the use of width measurements in facial asymmetry diagnosis should not be used since variance in errors in landmark identification can be larger than that in actual landmark location.

Mandibular length is measured on cephalographs to depict changes during growth and after orthodontic treatment, and is often defined between condylion (Co, most posterior superior point on the condylar outline) and pogonion (Pog, most anterior point on the chin). The aim of this study was to assess the accuracy of identifying condylar anatomy, thus the validity of using Co-Pog to evaluate mandibular growth. The sample included 34 children from a prospective study on the early treatment of distoclusions. Two lateral head films were taken of each child, the first with the mouth closed (MC), the second with the mouth open (MO). Three examiners, two orthodontists (U.H. and K.H.) and a dental radiologist (R.B.), rated the condyle as identifiable, nonidentifiable, and interpreted. The rating was applied to the left (L) and right (R) condyles, or to only one outline (O) when the R and L structures appeared superimposed and were not distinguished separately. Besides Co-Pog, the orthodontists traced sella-nasion (SN) and incisor tip-menton (I-Me) to evaluate variability in measurements that do not include Co. One operator (J.G.) measured all distances. Agreement among the three examiners was best in rating the MO radiographs (50%): 4.1% identifiable, 5.9% nonidentifiable or interpreted; in the MC films, they agreed in 32.3% of the cases, but only one of the ratings was identifiable (2.9%). The highest agreement was in identifying the left condyle on the MO film (35.3%). Intraclass correlation coefficients for CO-Pog ranged from r = 0.73 (L side) to r = 0.92 (O) for one orthodontist, and for the other from r = 0.76 (O) to r = 0.85 (L). Both orthodontists had high correlations for SN and I-Me between MC and MO (0.94 < r < 0.98). The variability between examiners in recognizing condylar anatomy, particularly on radiographs taken with the mouth closed, suggests that the identification of condylar anatomy must be rated in studies of mandibular growth. Researchers measuring mandibular length in investigations of mandibular growth after orthodontic therapy should differentiate between cases where the condyle is readily identified, and those where condylar anatomy is interpreted.

The elegance of the cervical region is due to a certain balance between concave and convex surfaces, and is based on the presence of a well-defined cervicomental angle, generally between 90 degrees to 110 degrees. An excessively wide-open cervicomental angle makes the cervical profile inelegant. Numerous surgical techniques can improve this angle. There is however a certain limit to this correction: an excessively caudal and anterior hyoid bone. In this case the last proposal is a modification of the hyoid bone position in order to replace it in a backward and upper location. To achieve this goal we studied postero-superior suspension of the hyoid bone by plication of the tendon of the digastric muscle in 20 anatomic dissection. Each an dissection was controlled by x-ray of the profile of the cervical region before and after application of this technique. Cephalometric measures were performed and statistically analysed using the "Paired t-test" on Statview II. Analysis of the results after the plication of the tendon of the digastric muscle, demonstrated an average closing of the cervicomental angle of 25.6 degrees with an average ascent of the hyoid bone of 13.27 millimeters and an average posterior transposition of 3.75 millimeters. This experimental cervicoplasty appears to be feasible. A precise surgical technique has been developed with an easy approach to the digastric tendon during standart faced lift procedures. The effect of the compression generated on the pharyngo-oesophageal complex by posterior transposition of the hyoid bone is unknown. This problem is now under investigation.

Purpose: This study determined the anatomic location and the dimensions of the genial tubercles in relation to the apices of the mandibular central incisors., Materials and Methods: Linear cross-sectional tomographic images were made of 41 adult human skulls. A 2-mm-thick section was produced through each central incisor. The vertical distance between the apex of each central incisor and the level of the superior aspect of the genial tubercle was measured on the radiographs. Additional measurements were taken on the dry skulls to determine the horizontal distance between the apices of the two central incisors and the width and height of the genial tubercle., Results: Although 5 mm is considered a safe zone for geniotomies, 29 of the genial tubercles (35.4%) were less than 5 mm from the apices of the mandibular central incisors. The distance between the apices of these incisors ranged from 9 mm to 15 mm., Conclusion: Osteotomy of the genial tubercles can be performed within the confines of the mandibular central incisors, but care must be taken to avoid the root apices.

We observed four cases of temporomandibular joint fractures in children; all from indirect chin traumas. Traditional X-ray is not enough for a correct radiological diagnosis. CT, in particular with the axial scans, electronics coronal reconstructions, and where is possible direct sagittal scans, is able to give us a correct diagnosis about the nature and the site of the fractures.

Twenty-five Chinese patients who had undergone advancement genioplasty were evaluated for soft tissue changes of chin. The effects of bony genioplastic advancement on soft tissues of profile were studied by means of computerized cephalometric analysis. The change ratios between soft tissue and hard tissue, as well as regression equations were calculated. The result of this study led to the following conclusions: The soft tissue chin point and labiomental sulcus moved by 85% and 41% of horizontal advancement of the mandibular symphsis.

This study was designed to quantify the intraexaminer and interexaminer reliability of 52 commonly used posterior anterior cephalometric landmarks. The horizontal and vertical identification errors were determined for a sample of 33 skulls and 25 patients. The results show that there is a considerable range in the magnitude of error with different horizontal and vertical values. Interexaminer landmark identification error was significantly larger than intraexaminer error for many landmarks. The identification error was different for the skull sample compared to the patient sample for a number of landmarks. The relevance of knowing the identification error for each landmark being considered in a particular application was discussed.

The results of chin augmentation by porous hydroxyapatite blocks were evaluated clinically and radiographically in nine patients. Recovery of a satisfactory facial profile was achieved by the procedure, and all patients but one, with removal of the implant because of infection, were satisfied with the results of the surgery. Radiographically, the implants were incorporated into the bony structure of the mandible by deposition of bone at and around the bone-implant interface and ingrowth of bone into pores. Cephalometrically, the procedure was found to provide very stable results, with little change in the position of the implants and no appreciable resorption of the implants and bone. Despite heavy chemotherapy, histologic examination of the removed hydroxyapatite showed the presence of areas with numerous inflammatory cell infiltration and no bone formation. Thus, the procedure is quite useful for chin augmentation, but utmost care should be taken to avoid infection.

Panoramic radiographs were made of 75 dry, adult human mandibles. The size and position of the mental foramen in relation to the second premolar was determined. The mental foramen on panographic radiographs was slightly larger than reported on periapical radiographs. The average position of the foramen was mesial and below the radiographic apex of the tooth. Panoramic radiography may account for a distal shift of the foramen and a 23% increase in size of the mandibles examined.

This study tested the relationships between the rate of mandibular residual ridge resorption and the following two variables: cortical thickness at the gonion, and the proportion of cortical bone at the symphysis. These parameters were also compared between men and women. Measurements of cortical thickness at the gonion on panoramic radiographs were compared with similar measurements on lateral cephalometric radiographs. The results showed that neither cortical thickness at the gonion nor the proportion of cortical bone at the symphysis could be used as radiographic predictors of the rate of mandibular bone resorption. The rate of resorption was significantly greater in men than in women, while cortical thickness at the gonion in women was significantly less than that in men. Furthermore, the authors concluded that cephalometric and panoramic measurements should not be used interchangeably.

The aim of this study was to use densitometry of lateral skull teleradiographs to evaluate the changes that occurred in the lower lip and chin after orthodontic or orthodontic-surgical treatment of Class III malocclusion. Forty teleradiographs from 20 patients with mandibular prognathism were made at the beginning and end of treatment. In ten of these patients the treatment was exclusively orthodontic with an edgewise appliance, and in another ten the treatment was orthodontic with a straight wire appliance combined with orthognathic and mentoplastic surgery. In the patients who were only treated orthodontically, a significant increase in density of the lower lip and the chin was found after treatment. This seemed to be related to an increase of muscular tension in these areas. Patients treated with orthognathic surgery and the straight wire appliance showed a decrease in density of the chin after treatment, but not of the lip. This can be interpreted as a consequence of muscular normalization after this procedure was accomplished.

There is still some controversy on condylar cartilage growth capacity, whether it is similar or not to long bones growth cartilage. Recently it has been set that human tibial proximal growth decreases gradually throughout the second half of pregnancy period. The aim of this study is to determine whether changes are produced within mandibular condylar cartilage during fetal period are similar or not those that take place in growth platform. Lateral X-rays from the right half of the mandible of 19 human foetus between 18 and 41 weeks had been obtained. Total mandibular length, corpus length, ramus length and gonial angle were measured. A hystological condylar study was made, recording its thickness from sagittal sections of the central condylar area. Total mandibular length as well as corpus and ramus length progressively increased during studied period, existing high correlation between those parameters and gestational age and weight. Gonial angle decreases in studied period. Changes in condylar thickness were correlated neither with pregnancy age nor with fetal weight or X-rays mandibular parameters. These outcomes show that changes in mandibular condyle are not similar to those produced in tibial growth proximal platform and suggest condylar modifications could be more related to local factors than with general body growth mechanisms.

Positional changes of the chin (symphysion = sy) following unilateral condylar fractures of the mandible were studied in 21 children and 20 adults by means of repeated radiographic examinations. On each occasion and for each individual the actual position of the sy was related to an estimated normal position. In those children in whom the remodeling processes in the temporomandibular joint (TMJ) resulted in normal skeletal relation, the result of the subcondylar fractures seemed to be a deviation of the sy towards the nonfractured side. In cases of condylar head and neck fractures a deviation towards the fractured side frequently occurred. In four of the five children in whom normal skeletal relation in the TMJ was not obtained, the sy deviated towards the condylar fracture side. In the majority of the adulsts, a deviation towards the condylar fracture side occurred irrespective of the level of the condylar fracture.

Changes in the vertical dimension of mandibular rest position for 50 subjects wearing complete dentures were measured on cephalometric radiographs between lead markers attached to the face and between skeletal landmarks. Measurements between the landmarks were compared on radiographs made without (edentulous) and with (edentoprosthetic) the dentures in the mouth. The findings support the following statements. The facial structures tended to mask the positional changes of the mandible. The rest position of the edentulous mandible tended to vary within the time frame of the cephalometric examination. The range of measurements of the skeletal rest position appeared greater with greater denture age and experience of the subjects. The rest position of the edentoprosthetic mandible (with dentures in the mouth) was more frequently constant when measured skeletally than when measured facially and more frequently constant than the edentulous mandibular rest position. The edentulous mandibular rest position of most subjects was increased upon insertion of dentures. The rest position was decreased for the remainder of the subjects. As a group, those subjects whose mandibular rest position decreased (up-shifted) with insertion of dentures had older dentures and more years of denture-wearing experience than subjects whose mandibular rest position increased (down-shifted) with insertion of dentures. The edentulous mandibular rest position does not seem particularly suitable for determination of the vertical dimension of occlusion and appears somewhat less suitable when facial measurements are used.

The treatment results in 31 consecutive patients treated with Proplast for chin augmentation show good clinical succes with the implant. A critical analysis of treatment results reveals that attention to certain details of the preoperative evaluation, surgical technique, and postoperative care can make for impressive results. These facts are discussed.

After insisting on the strict and precise manner with which the clinical examination should be carried out, the author provides a detailed description of Delaire's functional genioplasty, one which has the advantage of combining physiology and esthetic. Several clinical cases are used to illustrate this surgical technic and other examples of genioplasty are described. Genioplasty is in fact a surgical act which gives excellent esthetic results, but its indications must be carefully considered.

The bony chin is not placed in its position by chance. As with the other skeletal pieces of the face, it is controlled by the major laws of craniofacial morphologic and functional equilibrium. Clinical evaluation of anomalies of position of the bony chin in the three spatial planes is not sufficiently precise, and craniofacial structural and architectural analysis is an essential aid for determining origin of the mental dystopia and surgical remedial means. The aim of the latter is to restore the bony chin to its position of craniofacial equilibrium, the only way to obtain a stable functional result.