Mandibular Body Height Research Articles

Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients

This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested. Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n= 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n= 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides. Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P= 0.412 and P= 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P= 0.011, P= 0.024, and P= 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P= 0.008), mandibular ramus height (P= 0.004), condyle height (P= 0.010) and gonion to midsagittal plane distance (P= 0.018). Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Abaloparatide and teriparatide enhance mandibular growth in adolescent rats with site-specific and mechano-related effects.

Teriparatide (TPTD) and abaloparatide (ABL) are two osteoanabolic drugs targeting parathyroid hormone (PTH)1R signalling. This study aimed to investigate the effects of TPTD and ABL on the adolescent mandibular growth. In total, 70 4-week-old male Sprague-Dawley rats were randomly divided into 14 groups, treated with intermittent TPDT or ABL at various doses, accompanied by mandibular advancement (MA) or not. 3D printing was used to fabricate an innovative splint for MA. After a 4-week treatment, morphological measurement, histological and immunohistochemical analysis were performed. Mandibular condylar chondrocytes (MCCs) were treated with TPTD or ABL, followed by CCK-8 assay, alcian blue staining, real time-PCR and immunofluorescent staining. In vivo, TPTD or ABL alone increased the condylar length and cartilage thickness, with up-regulated SOX9 and COL II, whilst down-regulated COL X; however, when combined with MA, the promotive effects were attenuated. TPTD or ABL alone increased the mandibular body height and mandibular angle width, whilst increased the mandibular body length and alveolar bone width when combined with MA. In vitro, TPTD or ABL enhanced the MCC proliferation, glycosaminoglycan synthesis, COL II and SOX9 expression, whilst down-regulated COL X, Ihh and PTH1R expression. Both ABL and TPTD enhance mandibular growth in adolescent rats with site-specific and mechano-related effects, including propelling chondrogenesis at the condylar cartilage and promoting bone apposition at other mechano-responsive sites. They behave as promising drugs for mandibular growth modification, and in general ABL seems more potent than TPTD in this context.

Detection and diagnosis of cleidocranial dysplasia by panoramic radiography: a retrospective study

BackgroundCleidocranial dysplasia (CCD) is a rare and underdiagnosed congenital disorder in dentistry. The purpose of this study was to illustrate and quantify the maxillofacial bone abnormalities detected on panoramic radiographs from a relatively large retrospective case series and to provide a series of diagnostic references for dentists to indicate the presence of disease and help in making an early and accurate diagnosis.MethodsThe dental panoramic radiographs of thirty CCD patients aged 11 to 45 years (18 males and 12 females) were examined retrospectively. The dentition states, including supernumerary teeth and impacted teeth, were recorded. Twelve quantified measurements were adopted to determine the abnormalities of maxillofacial bones, including the degree of the zygomatic arch downward bend, bicondylar breadth, ramal height, mandibular height, mandibular aspect ratio, mandibular body height, condylar height, coronoid height, distance between the coronoid process and the condyle, bigonial width, gonial angle and best-fit gonial circle diameter. The Wilcoxon rank-sum test was used to compare the findings of the CCD patients with those of their matched controls (n = 300).ResultsSupernumerary teeth were detected in 27 patients (90.0%), and all 30 patients presented impacted teeth. Compared to the matched controls, the CCD patients had a significantly larger degree of zygomatic arch downward bend (ZAD), a larger diameter of the best-fit gonial circle (BGC), and a shorter distance between the coronoid process and the condyle (DCC) in panoramic radiographs (P < 0.001). According to the reference cutoff values established from the 5th or 95th percentile of the measurements in the control group, ZAD higher than 6.90 mm, DDC less than 22.37 mm and BGC higher than 52.41 mm were significantly associated with the CCD features identified. Other panoramic measurements were not significantly different between the two groups.ConclusionsPanoramic radiographs had great value in the diagnosis of CCD. In this study, we identified some dental and maxillofacial features on panoramic radiographs from a relatively large retrospective case series of CCD. A series of reliable quantitative indicators were provided for dentists that can indicate the presence of disease and improve the diagnostic specificity.

Impact of Diet Consistency on the Mandibular Morphology: A Systematic Review of Studies on Rat Models.

Apart from genetics, environmental factors, such as food consistency, may affect craniofacial morphology and development. The present systematic review aims to systematically investigate and appraise the available evidence regarding the effect of diet consistency on the anatomical structures of the basal bone of the rat mandible. The search was performed without restrictions in five databases (PubMed, Scopus, Web of Science, ProQuest Dissertations and Theses Global, including grey literature) and hand searching through January 2022. A total of 14,904 references were initially identified, and 16 articles were finally included in the systematic review. Rats that consumed hard diets were found to exhibit an increase inbigonial width, corpus height, condylar depth, condylar base inclination, condylar process inclination, mandibular plane inclination, height and length of angular process, mandibular body height, depth of antegonial notch, growth rate in the gonial angle, angular process convexity and height of condylar process. It was also noted that mandibular depth, mandibular height, ramus angle and angle between the angular process and mandibular plane were decreased in rats that were fed with a hard diet. On the other hand, there were conflicting results about the growth of mandibular length and width, corpus length, mandibular body length, ramus height, condylar length and width, gonial angle and height of coronoid process. From the abovementioned results, it can be concluded that food consistency may affect the morphology of anatomical structures and the overall growth and development of rat mandibles in various ways.

Radiologic Risk Factors for Persistent Mandibular Nerve Neurosensory Disturbance Following Sagittal Split Osteotomy

Neurosensory disturbance (NSD) occurring in the lower lips and chin is a major postoperative complication related to bilateral sagittal split osteotomy (SSO). The purpose of this study is to identify preoperative radiographic findings following SSO procedure associated with persistent NSD. This retrospective cohort study analyzed data for consecutive patients who underwent SSO. Primary predictor variables, including ramus width, mandibular body height, mandibular angle length, gonial angle, distance from mental foramen to distal aspect of mandibular second molar (MFD), and measurement of bone marrow space (BMS), were examined in a series of radiographic images. The primary outcome variable was NSD. Patients with NSD were divided into 2 groups based on findings obtained 1year postoperatively: persistent, for those with NSD remaining after 1year, and transient, when NSD occurred for less than 1year. Covariates included sex and age. Comparisons were analyzed by use of Mann-Whitney U test or χ2 test. Multivariate analysis was performed using step-wise logistic regression to determine significant factors related to persistent NSD. A P value .005 or less was considered statistically significant. Of the 349 sides investigated, the persistent NSD group consisted of 59 sides (16.9%), while the transient NSD group consisted of 290 sides (83.1%). The occurrence of persistent NSD was correlated with age (P<.05), MFD (P<.001), mandibular body height (P<.05), and BMS (P<.001). Multivariate logistic analysis also showed a significant association of MFD (P<.001) and BMS (P<.001). Preoperative MFD and BMS are radiographic findings that are associated with an increased risk for persistent NSD following SSO procedure.

Association of the three-dimensional skeletal variables with self-recognition of facial asymmetry in skeletal Class III patients.

To investigate the association between three-dimensional (3D) skeletal variables and self-recognition of facial asymmetry in skeletal Class III patients. Questionnaires and cone beam computed tomography of 74 patients (42 men and 32 women; mean age: 22.8 ± 4.5 years) with skeletal Class III and facial asymmetry were collected retrospectively. Patients were classified into three groups: group Sy (recognition of symmetry), group NS (not sure), and group Asy (recognition of asymmetry), according to their responses to the questionnaires. To assess 3D anatomic differences in the maxillomandibular region, six 3D hard tissue variables: maxillary height, ramal length, frontal ramal inclination (FRI), lateral ramal inclination (LRI), mandibular body length (Mn BL), and mandibular body height (Mn BH) were compared among the three self-recognition groups. Six 3D hard tissue variables and Menton deviation were reduced into three factors and their association with the self-recognition of facial asymmetry was investigated. Maxillary height, FRI, LRI, Mn BH, and Menton deviation demonstrated significant differences among the three self-recognition groups. The reduced factors, which consisted of transverse and vertical parameters, and vertical parameter of the mandibular corpus, demonstrated significant differences among the three self-recognition groups. The difference in Mn BH influenced the self-recognition of facial asymmetry. Both the transverse and vertical parameter of the skeleton were determinant in self-recognition of facial asymmetry. Identification of the skeletal difference in the lateral view involving LRI and Mn BH should be included for assessment of facial asymmetry.

Gender and Age Differences in Mandibular Ramus and Body Measurements: A Radiographic Study

The dental panoramic radiographs (PR) and lateral cephalographs (LC) of 140 subjects in the age group between 5 and 24 years were examined to evaluate the mandibular morphology in relation to gender and age. The examined films were divided into seven age groups. The bigonial width (BW), mandibular body height (MBH) and length (MBL), mandibular ramus width (MRW), height (MRH) and length (MRL), and gonial angle were recorded, measured and the data analyzed. Level of significance was set at 0.05. In our study the mean value of BW and MRW increased in both gender with increasing age up to age 17 years, then began decreasing. The anterior and posterior MBH and MBL increased with increasing age for both genders with statistically significant differences between the first and second groups (p< 0.05) and the fourth and fifth groups (p< 0.05) for anterior MBH, and between the third and fourth groups (p< 0.05) for posterior MBH and MBL (p< 0.05). MRH and MRL also increased with increasing age with statistically significant differences between the third and fourth (p< 0.05) and the fourth and fifth (p< 0.05) age groups for MRH and the fourth and fifth (p< 0.05) and fifth and sixth (p< 0.05) age groups for MRL. On the other hand, the gonial angle decreased with increasing age but without significant differences. Knowledge of mandibular growth is important factors for diagnosis and treatment planning in orthodontics as well as community medicine for monitoring the growth of children.

Mandibular Ramus Sexual Dimorphism Using Panoramic Radiography

Background: Identification of human remains is the first essential phase of forensic investigation and is significant for subsequent analyses. Mandible is the most dimorphic, largest, and hardest bone of skull and plays a decisive role in sex determination, especially when the complete skull is not available. This study aimed to examine the accuracy of mandibular ramus assessment in sex discrimination using panoramic radiography. Methods: A total of 135 panoramic radiographs (68 males and 67 females; aged 0-75 years) were retrieved from the database of the Department of Oral and Maxillofacial Radiology, Ahvaz Jundishapur University of Medical Sciences, Iran and divided into five groups :4-14, 16-30, 31-45, 45-60, and 61- 75 years. The following four parameters were measured on the radiographs utilizing the mouse-driven method to determine sex: coronoid height (CRH), ramus height (RH), mandibular body height (MBH), and bicondylar breadth (BB). The radiographs were processed using the SCANORA® software. Data were analyzed using receiver operating characteristics (ROC) graphs, t test, and the IBM SPSS software version 22.0 (IBM Corp., Armonk, N.Y., USA). Results: The percentage of certainty of each variable regarding the determination of sex from an unknown human mandible bone was as follows: RH=84.6%, CRH=82.4%, BB=73.5%, and MBH=83.8%, indicating that RH alone could categorize the sex in 84.6% of the cases (highest accuracy), CRH in 82.4%, BB in 73.5% (lowest accuracy), and MBH in 83.8%. The average accuracy in sex determination was 89% using all four variables. Conclusions: All the variables studied in the present study revealed a reliable extent of certainty for sex discrimination of unidentified skeletal remains. The overall accuracy of all variables altogether was 89%.

Free fibula flap for reconstruction of the severely atrophic mandible: a retrospective study

The purpose of this retrospective study was to assess the feasibility of using a free fibula flap (FFF) for reconstruction of the alveolar region of the severely atrophic mandible, by determining bone stability after dental implant insertion and prosthetic rehabilitation in a series of eight female patients aged 36–65 years. Dental implant insertion was performed 3–4 months after reconstruction. Prosthetic loading was performed 3–4 months after implant insertion. The height of the reconstructed mandible after surgery was 21.20±1.87mm, with an increase of 8.80±1.71mm from the preoperative height. The height of the FFF immediately after reconstruction was 11.24±1.10mm; this showed a vertical loss of 0.99±0.52mm (8.79%) and maintenance of 91.21% of the initial height at a mean 14 months post-reconstruction. Applying the Wical and Swoope formula to estimate the original mandibular body height, it was found that the difference between this calculated height (21.17±3.76mm) and the reconstructed height (21.20±1.87mm) was only 0.03±3.17mm (0.14%). An overall insignificant decrease of 0.46±1.14 cm3 in FFF volume had occurred at 3–4 months after dental implant functional loading, while in two cases an increase in volume was found (1.22cm3 and 1.71cm3). The good and stable results obtained show that the FFF may be used to reconstruct the whole mandibular alveolar region, with the best possible outcomes.

Computer-assisted versus traditional technique in fibular free-flap mandibular reconstruction: A CT symmetry study

ObjectivesIn the past few years, virtual planning has been increasingly used for mandibular reconstruction. The objective of our study was to evaluate and compare symmetry and the accuracy of morphologic reconstruction in patients undergoing mandibular reconstruction by fibular free flap between traditional freehand technique and computer-aided surgical cutting guides. Material and methodsA single-center retrospective study included all cases of mandibular reconstruction using fibular free flap. In the three-dimensional (3D) group, virtual surgery planning with cut guides was used (Materialise ®), while the Control group underwent traditional freehand reconstruction. Morphometric comparisons were made to evaluate reconstruction accuracy between pre- and post-operative CT scans (mean deviations of 3 angles and 3 lengths). Mandible symmetry was calculated by comparing each angle and length in the affected and non-affected sides of the mandible. ResultsThirty-three patients treated between January 2015 and June 2018 were included: 25 patients in the 3D group and 8 in the control group. The average number of mandibular segments was 2.16±0.55 in the 3D group and 1.75±1.16 in the control group (p=0.005). Mean deviations between pre- and post-operative values of the coronal mandibular angle (angle formed by the line through the two condyles and the ramus), mandibular body height and mandibular ramus length on the affected side were significantly lower in the 3D group than in the control group. Sagittal mandibular angle symmetry was better in the 3D group than, in the control group (ratios of affected over non-affected sides: 1.07±0.04 vs 1.12±0.1; p=0.034). ConclusionVirtual surgical planning for fibula free-flap reconstruction helps to improve reconstruction accuracy and maintains a significantly greater symmetry than the traditional freehand technique, and should improve functional and esthetic outcome in mandibular reconstruction.

Study of Various Osteometric Parameters of Human Mandible in Adult and Elderly Age Groups

The cardinal points of identity establishment can be met out with the help of mandibular anthropometry, when the bone is available for examination. A number of metric and non- metric parameters help in estimating the age from the mandible; which accurately differentiates various stages of life cycleThe main aim of this study is to study the various osteometric parameters of human mandible in adult and elderly age groups; and to determine their significance and utility for the purpose of identification in forensic sample.For the purpose, 200 mandibles were measured anthropometrically. The data was collected in master chart and statistically analysed.Height of the mandibular body, thickness of the mandibular body and maximum ramus height were found to be statistically significant parameters. Hence, these parameters could be used for allocation of a mandible to adult or elderly age group. It is also recommended to include other morphometric parameters of mandibles in the study to increase the accuracy and precision.

Effects of nicotine exposure on murine mandibular development.

Nicotine is known to affect cell proliferation and differentiation, two processes vital to proper development of the mandible. The mandible, the lower jaw in mammals and fish, plays a crucial role in craniofacial development. Malformation of the jaw can precipitate a plethora of complications including disrupting development of the upper jaw, the palate, and or impeding airway function. The purpose of this study was to test the hypothesis that in utero nicotine exposure alters the development of the murine mandible in a dose dependent manner. To test this hypothesis, wild type C57BL6 mice were used to produce in utero nicotine exposed litters by adding nicotine to the drinking water of pregnant dams at concentrations of 0 μg/ml (control), 50 μg/ml (low), 100 μg/ml (medium), 200 μg/ml (high) throughout pregnancy to birth of litters mimicking clinically relevant nicotine exposures. Resultant pups revealed no significant differences in body weight however, cephalometric investigation revealed several dimensions affected by nicotine exposure including mandibular ramus height, mandibular body height, and molar length. Histological investigation of molars revealed an increase in proliferation and a decrease in apoptosis with nicotine exposure. These results demonstrate the direct effects of nicotine on the developing mandible outside the context of tobacco use, indicating that nicotine use including tobacco alternatives, cessation methods, and electronic nicotine delivering products may disrupt normal growth and development of the craniofacial complex.

Altering calcium and phosphorus levels in utero affects adult mouse mandibular morphology.

The purpose of our study was to determine morphological changes and bone mineral density (BMD) differences in the adult mandible of offspring exposed to high calcium, low phosphorus diets in utero until weaning age. Time-mated FVB wild-type mice were fed normal or experimental diet during gestation and until weaning of offspring. Experimental diet contained 3-fold increase in calcium and 3-fold decrease in phosphorus compared to normal diet. Adult mandibles of offspring exposed to experimental diet were sacrificed and heads scanned using micro-computed tomography. Three-dimensional 3D geometric morphometric analysis GMA was utilized to detect morphological changes to the mandible including the condyle. Experimental females showed the greatest morphological differences including shortened mandibular ramus width and height, shortened mandibular body length and height, a wider but shortened condylar neck and a wider condylar head in the lateral-medial direction. Experimental male mandibles trended towards increased mandibular body height and length, opposite the changes observed in experimental female mandibles, whereas condyles were similar to that observed in experimental females. Bone mineral density (BMD) was lowered in experimental females. Increased calcium and decreased phosphorus levels led to a retrognathic mandible associated with lowered BMD in experimental females, whereas experimental showed partly opposite effects. Further studies are required to understand the mechanism underlying diet- and gender-specific differences in mandibular morphology.

Exploratory study of the three-dimensional morphological variation of the jaw associated to teeth loss

PurposeThe aim of this study is to evaluate the morphological variability in mandibles with different types of edentulism, comparing the use of traditional morphometrics and tridimensional geometric morphometrics. MethodsTraditional morphometrics and geometric morphometrics (GM) exploratory analysis, by principal components (PCs) and PC scores, were performed on a sample of 24 cadaveric hemi mandibles. A digital reconstruction of 3D surfaces of each specimen was obtained by CT scans segmentation. The mandibles were divided in three groups: full dentition (G1), partial edentition (G2) and total edentition (G3). The results of the two methods were compared in relation to the morphological variability determined with each method. ResultsBoth methods were consistent in terms of morphological variability between the defined groups. The main shape variations observed were a decrease in mandibular body height, a widening of the cross sectional morphology on the symphysis, a shorten-narrowed Ramus and a deeper sigmoid notch, in the partially or totally edentition groups, compared to the full dentition group. DiscussionThe general patterns of morphological variations associated with edentulism that have been reported in literature could be visualized with GM method, which had not been previously used for this purpose. The GM methods could offer a more detailed definition of shape variations, which is critical in a clinical context. Moreover, GM allowed defining configurations of mean morphologies and an image library with different types of morphological variations.

Integrity of Human Mandibular Angle After Block Graft Harvest from Mandibular Body.

To examine human mandibular angle integrity alterations accompanying a mandibular body block graft harvest surgical procedure. Hemimandibles from 24 human cadavers were resected and sorted into one of three groups by residual dental status. The height of each hemimandible body was obtained and recorded. Acrylic bone cement was utilized to mount the hemimandibles at the mandibular condyle. Using standard surgical instruments and techniques, cortical bone of the mandibular body buccal plate was resected from the right hemimandibles. Left hemimandibles were used as a control. Each hemimandible was secured in an Instron 5565 mechanical unit. With forces placed on and perpendicular to the occlusal plane, each hemimandible underwent sequential loading until osseous fracture occurred. Descriptive statistics between grouped data were compared and discussed in terms of mean, minimum, and maximum. The statistical relationship between the maximal load, gender, and mandibular body height were identified. Donor and control hemimandible maximal load mean values were 423.63 N and 957.90 N, respectively. A statistically significant difference was present between maximal loads of donor and control hemimandibles (P < .0001). Correlations of statistical significance were present between mandibular bone height and maximal load in the control hemimandibles (P = .009). Correlations of statistical significance were not found between mandibular bone height, displacement at maximal load, and maximal load in the grafted hemimandibles (P >.05). No statistically significant correlation between dental status and gender was found in the donor and control hemimandibles (P > .05). After subjected to a typical block graft harvest surgical procedure, the human mandible's integrity is significantly altered. Gender, dental status, and mandibular bone height do not correlate with maximal load,and thus integrity, of donor and control mandibles.

Assessment of the Integrity of Adult Human Mandibular Angle

The purpose of this study was to analyze the integrity of the adult human mandibular angle. The left hemimandibles of 24 human cadavers were selected and divided into three groups based upon remaining dental status. The height of the left mandibular body was measured. Hemimandibles were mounted in acrylic bone cement at the mandibular condyle. The left mounted hemimandibles were secured into an Instron 5565 mechanical unit and the occlusal plane was sequentially loaded until fracture of the mandibular bone occurred. Minimum, maximum, mean, and standard deviations for compressive force as well as displacement of the occlusal plane were derived and compared for descriptive statistics. The correlations between the gender, mandibular body height, and maximal load were examined. The mean mandibular heights among males and females were 22.44 mm and 17.53 mm, respectively. Results portrayed a significant correlation between gender and mandibular height. The mean maximal loads among males and females were 1,174.17 and 828.14 N, respectively. Results portrayed a statistically significant difference between males and females regarding maximum load as well as the height of the mandible ( p=0.0103 and p=0.0067, respectively). No statistically significant association between maximum load and dental status (presence/absence of molar teeth) was found ( p &gt; 0.05). The maximal load of human mandibular angle was found to be higher than that of the heavily investigated polyurethane synthetic mandible replica. The average height of the mandibular body in males was found to be greater than that of females. Mandibular body height showed a direct correlation to maximal load of the hemimandibular angle. In maxillofacial research, biomechanical evaluations of mandibular angle fractures and plating techniques with human cadaveric bone should be considered alongside or in place of conventional synthetic polyurethane mandibles.

Clinical Outcomes Between Atrophic and Nonatrophic Mandibular Fracture in Elderly Patients.

The number of elderly patients with mandibular fracture is rapidly increasing. To improve outcome, it is important to understand the age-related characteristics of mandibular fracture. Thus, the aim of this study is to analyze the impact of atrophic change on mandibular fracture in elderly patients. The retrospective study was conducted in patients aged ≥65 years old, who underwent surgery for the treatment of mandibular fracture in our hospital from March 2006 until March 2015. Patient characteristics, such as age and gender, causes of injury, anatomic location of fracture, height of mandibular body, extent of atrophy, location of surgical sites, postoperative outcomes, and the follow-up period, were examined. Descriptive statistics were compared between atrophic and nonatrophic mandibles. The patients included 17 males and 12 females and the mean age was 71.9 years old. The average follow-up period was 6.06 months. Regarding occlusion and complications, there were no statistical differences between the atrophic and nonatrophic mandibular fractures. As major complications, nonunion occurred in 2 patients and malunion in 1 patient. There was no mortality associated with anesthesia or surgery. Atrophic and nonatrophic mandibular fractures in elderly patients can be treated successfully with surgery. There was no significant difference with respect to major complications between patients with atrophic and nonatrophic mandibular fractures.

Craniometric variation among Brazilian and Scottish populations: a physical anthropology approach

Aim: The present investigation intended to compare the craniometric variations of two samples of different nationalities (Brazilian and Scottish). Materials and methods: The Brazilian sample consisted of 100 modern complete skulls, including 53 female skulls and 47 male skulls, and the Scottish sample consisted of 100 historical skulls (61 males, 39 females) and 36 mandibles (24 males, 12 females). The cranial measurement protocol was composed of 40 measurements, 11 bilateral and 29 unilateral, and the measurement protocol of the mandible was composed of 15 measurements, with six that were bilateral and nine that were unique. The comparative analysis of the metric variability between the two samples was performed using the means and medians analysis, the t-test, the Wilcoxon test, and the coefficient of variance, with a significance level of 5%. Results: The results showed that, among the 72 analysed variables, 44 measurements (61.11%) presented statistical differences between the samples. The Scottish skull tends to have a cranial length (GOL diff=5.53), breadth (XCB diff=3.78) and height (NPH diff=5.33) greater than the Brazilian skulls, and the Scottish mandibles tend to show a higher mandibular ramus height (MRH diff=9.25), a higher mandibular body height (HMB diff=6.37) and a larger bigonial breadth (BGB diff=5.29) than the Brazilians. The discriminant analysis of the 51 cranial measurements and 21 mandibular measurements showed a variation of the percentage of accuracy between 46.3-83.8%. Conclusion: The metric analysis demonstrated that there is variability between the two samples studied (61,11%), but a concrete cause cannot be determined considering the multifactorial aspects of the variations of form and size.

Corrective outcome and transverse stability after orthognathic surgery using a surgery-first approach in mandibular prognathism with and without facial asymmetry

The aim of this study was to evaluate corrective outcome and transverse stability after orthognathic surgery via a surgery-first approach (SFA) in mandibular prognathism with and without facial asymmetry using 3-dimensional analysis. Twenty-nine patients who received mandibular setback surgery using SFA were divided into 2 groups according to the menton deviation (4 mm): symmetry group (n = 17) and asymmetry group (n = 12). Using computed tomography images obtained before (T0), immediately after (T1), and 6 months after (T2) surgery, time-dependent changes in variables related to facial asymmetry, including maxillary height, ramal length, frontal and lateral ramal inclination, mandibular body length, and mandibular body height, were evaluated. Immediately after surgery, the asymmetry group showed significantly decreased discrepancies between the longer and non-longer sides for all variables (P < .05); there were no significant differences in discrepancies between the 2 groups. During the postoperative period, no significant changes in discrepancies were found in any variable in either group. Compared with T0, the asymmetry group showed significantly decreased discrepancies in ramal length, frontal and lateral ramal inclination, and mandibular body length at T2. Variables related to facial asymmetry showed significant improvement after surgical-orthodontic treatment using SFA, and corrected outcomes showed good postoperative stability in both the symmetry and asymmetry groups.

Morphometric and Morphological Study of Mental Foramen in the Malaysian Population: Anatomy and Forensic Implications

Introduction: The mental foramen is present on either side of the body of the mandible bone. This foramen transmits mental vessels and nerves. In forensic anthropology, mental foramen may be important for differentiating sex, estimating age and identifying various races based on morphology. The main aim of the present study was to determine the position, shape and diameter of the mental foramen according to sex, age and race by postmortem computed tomography in the Malaysian population. Materials and Methods: A total of 79 dentulous patients (48 males, 31 females) from 3 age groups (18-30 years, 31– 50 years, 51-74 years) were selected for this study, and ten parameters were observed for each mandible. The parameters were divided into two morphological and eight morphometric parameters. The morphometric parameters were measured by using Osirix MD Software 3D Volume Rendering. Results: Results showed that mandibular body length and height were significantly greater in males than in females by independent t-test. (p&lt; 0.05). However, the mandibular body height was found to decrease significantly with age in both sexes by one-way Anova. It was observed that the shape of mental foramen was 45.6% oval and 54.4% rounded. About 44.3% of them were in line with the longitudinal axis of the second premolar tooth. Conclusion: It was concluded that mental foramen may be used for identification purposes, particularly for sex, age and race determination.