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Here, we describe a new Jehol tapejarid skeleton tentatively referred to Sinopterus dongi, revealing some valuable cranial information about the palate and mandibular symphysis of this species. In the palate, the absence of the lateral process of the pterygoid indicates that the subtemporal fenestra is undivided, in contrast to the well-developed lateral process that subdivides the subtemporal and secondary subtemporal fenestrae in other azhdarchoids. The mandibular symphysis is elongated to about 58.7% of the mandible length, significantly longer than the other two Jehol tapejarids (52.9–53.7%) and much longer than other tapejarids (38.0–51.0%), except for the basal tapejarid Caupedactylus ybaka (~65%). The symphyseal shelf is extensive, flattened, and sculptured by sinuous ridges and pits. The ratio of its length to the symphysis is 34.4%, between that of the possible tapejarid Bakonydraco galaczi (43.9%) and the coexistent chaoyangopterid Eoazhdarcho liaoxiensis (26.7%), and much distinct from the well-reduced condition in other tapejarids. This discovery highlights the variation of the cranial morphology in the Tapejaridae and even the Azhdarchoidea. [ABSTRACT FROM AUTHOR]

Aim: To compare the linear and angular measurements of the mandibular symphyseal region using lateral cephalometric (LC) and cone beam computed tomography (CBCT) images. Materials and Methods: One hundred patients justifying both LC and CBCT exposures were included. Both lateral cephalometric and CBCT images of the patients were used for angular and linear measurements. Angular measurements included vestibular concavity and lingual and tooth inclination angles. Vestibular and lingual cortical bone and total bone thickness measurements were obtained for the comparison of linear measurements. Three radiologists performed the measurements on 200 images. Comparison of the measurements and the imaging methods were done using paired‐ and Wilcoxon t‐tests. Inter‐observer reliability was evaluated with the intra‐class correlation coefficient (ICC). Results: A significant difference was observed between measurements of two imaging methods for tooth inclination and vestibular concavity angles; however, no difference was found between LC and CBCT measurements for lingual inclination angle (p > 0.05). Vestibular cortical bone and total bone thickness measurements showed a significant difference (p < 0.05), whereas no difference was obtained in lingual bone thickness measurements of two imaging methods (p > 0.05). Conclusion: CBCT imaging is recommended in selected patients where recipient bone or bone augmentation site(s) reveal suspect in clinical examination and lateral cephalometric imaging may not reveal the true anatomic structure and relationships. [ABSTRACT FROM AUTHOR]

In studies of mammalian mastication, a possible relationship has been proposed between bilateral recruitment of jaw adductor muscle force during unilateral chewing and the degree of fusion of the mandibular symphysis. Specifically, species that have unfused, mobile mandibular symphyses tend to utilize lower levels of jaw adductor force on the balancing (nonchewing) than the working (chewing) side of the head, when compared to related species with fused symphyses. Here, we compare jaw adductor recruitment levels in two species of musteloid carnivoran: the carnivorous ferret (unfused symphysis), and the frugivorous kinkajou (fused symphysis). During forceful chewing, we observe that ferrets recruit far more working‐side muscle force than kinkajous, regardless of food toughness and that high working‐to‐balancing side ratios are the result of increased working‐side force, often coupled with reduced balancing‐side force. We propose that in carnivorans, high working‐to‐balancing side force ratios coupled with an unfused mandibular symphysis are necessary to rotate the hemimandible for precise unilateral occlusion of the carnassial teeth and to sustain laterally oriented force on the jaw to engage the carnassial teeth during shearing of tough foods. In contrast, the kinkajou's flattened cheekteeth permit less precise occlusion and require medially‐oriented forces for grinding, thus, a fused symphysis is mechanically beneficial. Research Highlights: Ferrets' (unfused mandibular symphyses) use of asymmetrical jaw muscle activity may optimi forces for carnassial shearing. Kinkajous' more nearly equal force may be facilitated by their fused symphysis and flat cheek teeth. [ABSTRACT FROM AUTHOR]

Abstract Objectives The objective was to investigate the details of the attachments of the mylohyoid muscle to the mandible anterior to the hyoid and mylohyoid lines to understand the positional relationship between the sublingual space and the mylohyoid, knowledge that is essential for dental implant surgery in the incisal region, as well as the routes of communication between the sublingual space and other spaces. Methods While evaluating the presence or absence of an anterior mylohyoid muscle fiber attachment to the mandible, sublingual gland herniation, spaces between muscle fascicles were also recorded as sites of penetration. The mean muscle thickness in each of these areas was also calculated. Results In all specimens, the mylohyoid originated not only from the mylohyoid line but also from the lingual surface of the center of the mandibular body (the mandibular symphysis) below the mental spines. The mylohyoid muscle fascicles were thickest in the posterior region, and further anterior to this, they tended to become thinner. Sublingual gland herniations passing through the mylohyoid were noted in the anterior and central regions, but not in the posterior region. Penetration between the muscle fascicles was most common in the central region, and no such penetration was evident in the posterior region. Conclusions These results suggest that the mylohyoid functions only incompletely as a septum, and that routes of communication from the sublingual space to the submandibular space may be present in both the anterior and central muscle fascicles of the mylohyoid. Therefore, bleeding complications during dental implant placement in the anterior mandible can be serious issues. There is a potential for sublingual hematoma that could compromise the airway by pressing the tongue against the soft palate into the pharynx.

Objectives: The objective was to investigate the details of the attachments of the mylohyoid muscle to the mandible anterior to the hyoid and mylohyoid lines to understand the positional relationship between the sublingual space and the mylohyoid, knowledge that is essential for dental implant surgery in the incisal region, as well as the routes of communication between the sublingual space and other spaces. Methods: While evaluating the presence or absence of an anterior mylohyoid muscle fiber attachment to the mandible, sublingual gland herniation, spaces between muscle fascicles were also recorded as sites of penetration. The mean muscle thickness in each of these areas was also calculated. Results: In all specimens, the mylohyoid originated not only from the mylohyoid line but also from the lingual surface of the center of the mandibular body (the mandibular symphysis) below the mental spines. The mylohyoid muscle fascicles were thickest in the posterior region, and further anterior to this, they tended to become thinner. Sublingual gland herniations passing through the mylohyoid were noted in the anterior and central regions, but not in the posterior region. Penetration between the muscle fascicles was most common in the central region, and no such penetration was evident in the posterior region. Conclusions: These results suggest that the mylohyoid functions only incompletely as a septum, and that routes of communication from the sublingual space to the submandibular space may be present in both the anterior and central muscle fascicles of the mylohyoid. Therefore, bleeding complications during dental implant placement in the anterior mandible can be serious issues. There is a potential for sublingual hematoma that could compromise the airway by pressing the tongue against the soft palate into the pharynx. [ABSTRACT FROM AUTHOR]

Nuhad A Hassan,1 Aseel S Khazaal Al-Jaboori,2 Afya Sahib Diab Al-Radha,3 Maisaa Q Ali,4 Raya M Albayati4 1Department of Oral Medicine, College of Dentistry, Mustansiriyah University, Baghdad, Iraq; 2Department of Prosthetic Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq; 3Oral Surgery and Periodontology Department, College of Dentistry, Mustansiriyah University, Baghdad, Iraq; 4Department of Dental Radiology, Al-Falah Center, Ministry of Health, Baghdad, IraqCorrespondence: Afya Sahib Diab Al-Radha, Oral Surgery and Periodontology Department; College of Dentistry, Al- Mustansiriyah University, Central Baghdad Post Office, Post Box (P.o.) 55418, Baghdad, Iraq, Tel +964(0)7816883387, Fax +964(0)0115372237, Email drafya_diab@yahoo.com; drafya_diab@uomustansiriyah.edu.iqBackground: Overdentures supported by dental implants are a useful treatment strategy for patients with edentulous mandibles. The aim of this study was to evaluate certain characteristics of the mandibular symphyseal edentulous cases for dental implant treatment using CBCT; and if it is associated with gender differences.Methods: Ninety patients (45 females and 45 males) were included in this investigation. A section along the midline of each CBCT image was chosen for the edentulous symphyseal area. Symphysis height, width, and cortical thickness was measured for each patient. Bone density were calculated at four points A two-sample Student’s t-test and Pearson correlation were used for statistical analysis.Results: Males had a considerably greater symphysis height (26.66± 6.21 mm) than females (24.07± 5.00 mm) (p = 0.02). Similar results were found for bone width; males had greater means than females. In case of cortical bone thickness; males had thicker bone cortex in the buccal region than females (p = 0.01). While the difference in bone density between genders was small. However, a positive relationship was recorded between symphysis height and width.Conclusion: Height and width of the mandibular symphysis were influenced by gender in edentulous patients, with men showing higher measurements. The reduction of symphyseal height decreased concurrently with the width after teeth were lost, while bone density was maintained in both genders with no difference between them. The lingual cortical bone is significantly thicker than the buccal cortex at the lower part of the symphysis.Keywords: mandibular symphysis, CBCT, dental implant, cortical thickness

This article discusses a study on the morphology of the mandibular symphysis and the sagittal inclination of the lower incisors in patients with class III malocclusion. The study found that the concavity angle of the mandibular symphysis was higher in patients with a hyperdivergent facial pattern compared to those with a hypodivergent facial pattern. The sagittal inclination of the alveolar part of the mandibular symphysis and the lower incisors decreased as the angle of facial divergence increased. The study also found that the dimensions of the mandibular symphysis varied among the different patterns of facial divergence. The findings suggest that evaluating the mandibular symphysis morphology is important for diagnosis and orthodontic treatment planning. [Extracted from the article]

Objective: This study was performed to investigate the effects of mandibular incisor (MnI) agenesis and divergent malocclusion type on mandibular symphysis inclination and morphology. Methods: A total of 162 selected patients were divided into two groups: one group consisted of patients with one or two congenitally missing MnIs, and another group comprised patients without tooth agenesis. Patients in each group were categorized into three divergent malocclusion groups (hypodivergent, normodivergent and hyperdivergent) according to the Frankfort mandibular plane angle, with 27 patients per group. Lateral cephalograms were used to evaluate mandibular symphysis inclination and morphology. Two‐way analysis of variance, simple main effect analysis and Tukey's test were used for statistical comparisons. Results: The agenesis group demonstrated a significantly greater retroclination of the mandibular symphysis than the non‐agenesis group in the normodivergent group. In the hypodivergent and normodivergent groups, the agenesis group showed a significantly smaller area of the alveolar bone with thinner width and shorter height than the non‐agenesis group. Conclusion: For the Japanese orthodontic patients, MnI agenesis caused a significantly great retroclination of the mandibular symphysis in patients with normodivergent malocclusion and significantly small area of the alveolar bone with thin width and short height in patients with hypo‐ and normodivergent malocclusions. [ABSTRACT FROM AUTHOR]

The aim of the present paper was to evaluate the morphology changes of the mandibular symphysis (MS) in a longitudinal retrospective cohort of class II untreated subjects. The study sample included 120 subjects followed during normal growth and examined at the age of 12 (T0) and 15 (T1) years. MS was traced using two landmarks and ten sliding semi-landmarks. The acquired morphological data were processed via Procrustes superimposition that allowed to study variation and covariation in MS'form according to specific variables such as age, gender, and skeletal pattern. The first two principal components (PCs) described more than 90 % of the total morphological variation. Both types of form changes of the symphysis could be associated with the different skeletal vertical growth patterns. Age and sex did not interfere with the form of chin symphysis. Moreover, there was no significant covariation between initial MS morphology and form modifications. Clinicians should not expect to be faced with spontaneous changes of the form of the symphysis during the orthodontic treatment of adolescents. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the general mandibular symphysis (MS) shape variation among Class III skeletal base, using geometric morphometric analysis. Pre-treatment lateral cephalometric radiographs of 254 patients aged 11-40 years old, with Class III skeletal base (ANB <1o) and lower incisor angle (<99o) were included. Nine-landmarks with x and y coordinates were identified on MS using TPSDig2 software, then exported into Morpho J for shape and statistical analysis. Principal component analysis showed that three main shape dimensions with a total variance of 74.6% represented the majority variation of samples. Procrustes Anova showed the shape of MS in Class III skeletal base to be mainly influenced by gonial angle, incisor inclination and sex (P<0.0001). Canonical variate analysis showed that high gonial angle groups had significantly narrower and elongated MS whereas low gonial angle groups had wider, bulbous and rounded MS (P<0.0001). The ratio of alveolar part to basal part was 1:5 in low gonial angle and 2:3 in high gonial angle. Males had significantly taller MS with narrower B point area compared to females (P<0.0001). Retroclined incisors exhibited taller and retroclined alveolar parts (P<0.0001). The shape of MS in Class III skeletal base varied at the alveolar part, basal part or both and it is influenced by gonial angle, incisor inclination and sex. Hence, understanding the shape variation of MS is important to aid orthodontic treatment planning. [ABSTRACT FROM AUTHOR]

Introduction: Mandible, also known as lower jaw, is the largest bone of skeleton of face. Symphysis menti is primary cartilaginous joint that ossifies completely by first year of life. The morphometric parameters of mandible are important in the diagnosis and treatment of mandibular symphyseal fractures especially in deciding size of implants. Aim and Objectives: The present study was undertaken to evaluate height of symphysis and symphyseal angle. Material and Methods: The parameters were measured in 110 macerated and dry mandibles from various medical colleges in western Maharashtra region. Results: In the present study, mean symphyseal height in dentulous group of mandibles was found to be 26.72 mm while in edentulous group, it was 22.22 mm. As well as, mean symphyseal angle in dentulous group of mandibles was found to be 65.02o while in edentulous group, it was 65.91o. These findings of this study will be useful to anatomists, implantologists, orthodontists, archeologists, forensic legal experts and maxillofacial surgeons.

Objectives. Facial perception depends on the different components of the face. The chin is a striking anatomical structure in the individual's identity and mandibular symphysis (MS) shape influences the adjacent soft tissue, determining facial harmony. In lateral cephalometry, the MS corresponds to the image of the mandibular body in its anterior curvature. It shape, inclination and thickness provide valuable information for orthodontic diagnosis and prognosis. Since facial features are associated with malocclusions, the present investigation aims to relate the height, thickness and inclination of the MS using Angle's Class. Methods. 495 lateral incidence cephalograms of an orthodontic population were analyzed using a previously developed and tested software. The sample was randomly selected and the height, thickness and inclination of the MS were measured. The values were statistically analyzed (p ≤ 0.05). Results. The distribution according to Angle's Class was 48.9% for Class I, 34.7% for Class II Division 1, 7.4% for Class II Division 2 and 8.9% for Class III. The MS height did not't show significant differences between the three dental classes. The MS thickness was significantly increased in Class II Division 2 and Class I subjects (p = 0,037). The MS inclination was significantly less in Class III subjects when compared to Class I and Class II Division 1 (p ≤ 0.001). Conclusions. The MS presented variations, which may be associated with a natural compensation against malocclusion, influencing the position of the teeth and their relationship with the other dento-craniofacial structures and with consequences on the facial harmony. [ABSTRACT FROM AUTHOR]

To compare new bone formation in mandibular critical-sized bone defects (CSBDs) in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats filled with bioceramics (BCs) with or without bone marrow mesenchymal stem cells (BMSCs). A total of 64 adult female Sprague-Dawley rats were randomized into four groups (n = 16 per group): Group 1 healthy, Group 2 diabetic, Group 3 osteoporotic, and Group 4 diabetic-osteoporotic rats. Streptozotocin was used to induce type 1 diabetes in Group 2 and 4, while bilateral ovariectomy was used to induce osteoporosis in Group 3 and 4. The central portion of the rat mandibular symphysis was used as a physiological CSBD. In each group, eight defects were filled with BC (hydroxypatatite 60% and β-tricalcium phosphate 40%) alone and eight with BMSCs cultured on BC. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2). In all groups (healthy, diabetics, osteoporotics, and diabetics-osteoporotics), the CSBDs filled with BC + BMSCs showed greater radiological bone union, BMD, histological bone union, and more VEGF and BMP-2 positivity, in comparison with CSBDs treated with BC alone (at 4 and 8 weeks). Application of BMSCs cultured on BCs improves bone regeneration in CSBDs compared with application of BCs alone in healthy, diabetic, osteoporotic, and diabetic-osteoporotic rats. [ABSTRACT FROM AUTHOR]

Objective: To compare new bone formation in mandibular symphysis critical-sized bone defects (CSBDs) in healthy and osteoporotic rats filled with bioceramics (BCs) with or without buccal fat pad mesenchymal stem cells (BFPSCs). Materials and methods: Thirty-two adult female Sprague–Dawley rats were randomized to two groups (n = 16 per group): group 1 healthy and group 2 osteoporotic (with bilateral ovariectomy). The central portion of the rat mandibular symphysis was used as a physiological CSBD. In each group, eight defects were filled with BC (hydroxyapatite 60% and β-tricalcium phosphate 40%) alone and eight with BFPSCs cultured on BC. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2). Results: In both groups, CSBDs filled with BC + BFPSCs showed greater radiological bone union, BMD and histological bone union, and more VEGF and BMP-2 positivity, compared with CSBDs treated with BC alone at 4 and 8 weeks. Conclusions: The application of BFPSCs cultured on BCs improves bone regeneration in CSBDs compared with BCs alone in healthy and osteoporotic rats. Clinical relevance: Our results may aid bone regeneration of maxillofacial CSBDs of both healthy and osteoporotic patients, but further studies are necessary. [ABSTRACT FROM AUTHOR]

Objective: In chondrogenesis, BMP signaling was inferred to exhibit regional specificity during Meckel's cartilage morphogenesis. This study aimed to explore the differences in BMP signaling activity between different parts of Meckel's cartilage and the impacts of BMP4 or ALK3 deficiency on the development of Meckel's cartilage during embryogenesis. Materials and methods: The BRE‐gal reporter mouse line was utilized to gain an overall picture of canonical BMP signaling activity, as assessed by X‐gal staining. Mouse models lacking either Bmp4 or Alk3 in neural crest cells (Wnt1‐Cre;Bmp4fl/fl and Wnt1‐Cre;Alk3fl/fl) were generated to explore the morphogenesis of Meckel's cartilage and the mandibular symphysis, as assessed by skeletal staining, histology, and immunostaining. Results: Different parts of Meckel's cartilage exhibited activation of different combinations of BMP signaling pathways. In Wnt1‐Cre;Bmp4fl/fl mutants, Sox9+ condensation of the chondrogenic rostral process failed to form, and the V‐shaped Runx2+ tissue was split in the median mandibular symphysis. The Wnt1‐Cre;Bmp4fl/fl and Wnt1‐Cre;Alk3fl/fl mouse models both exhibited truncated Meckel's cartilage, aberrant mandibular intramembranous bone, and tongue muscle abnormalities. Conclusions: The central hard‐tissue loss of both mutant mouse models led to a mandibular symphysis cleft, mimicking the typical sign of the median mandible Tessier 30 cleft in humans. [ABSTRACT FROM AUTHOR]

Dyrosauridae, a clade of neosuchian crocodyliforms, was a significant component of terrestrial and aquatic ecosystems across the latest Cretaceous to Paleogene of North Africa. Here, we report a dyrosaurid mandibular symphysis recovered from the middle–upper Campanian Quseir Formation near Kharga Oasis in the southern Western Desert of Egypt. This is a partial mandible (MUVP 635), including dentaries and splenials, assigned to Dyrosauridae based on its dental pattern, size, and the shape of the splenial in the symphysis. MUVP 635 exhibits alveolar diameters shorter than the interalveolar distances within the same row. Moreover, the seventh dentary alveolus is significantly large, comparable in size to the fourth dentary alveolus, while the sixth dentary alveolus is positioned close to the seventh dentary alveolus and is as small as the eighth dentary alveolus, which is adjacent to the ninth dentary alveolus. Phylogenetic analysis places MUVP 635 as an early-diverging member of Dyrosauridae, consistent with its middle–late Campanian age. It aligns with a polytomy with Chenanisuchus lateroculi and Anthracosuchus balrogus identified as the most basal members of Dyrosauridae. The discovery of new dyrosaurid material in the Quseir Formation extends the range of Dyrosauridae to the middle Campanian, highlighting the taxonomic richness of the dyrosaurid clade across North Africa and supporting hypotheses of the African origin for this family. [ABSTRACT FROM AUTHOR]

The aim of the present paper was to evaluate the morphology changes of the mandibular symphysis (MS) in a longitudinal retrospective cohort of class II untreated subjects. The study sample included 120 subjects followed during normal growth and examined at the age of 12 (T0) and 15 (T1) years. MS was traced using two landmarks and ten sliding semi-landmarks. The acquired morphological data were processed via Procrustes superimposition that allowed to study variation and covariation in MS’form according to specific variables such as age, gender, and skeletal pattern. The first two principal components (PCs) described more than 90 % of the total morphological variation. Both types of form changes of the symphysis could be associated with the different skeletal vertical growth patterns. Age and sex did not interfere with the form of chin symphysis. Moreover, there was no significant covariation between initial MS morphology and form modifications. Clinicians should not expect to be faced with spontaneous changes of the form of the symphysis during the orthodontic treatment of adolescents.

Background/purpose: Overdenture with single symphyseal implant is one of the useful clinical approach for elderly edentulous patients. We aimed to evaluate edentulous patients with regards to the relationship between dimensions, bone characteristics, cancellous densities, and cortical thickness of the mandibular symphyseal region using cone beam computed tomography (CBCT). Material and methods: We analyzed 103 CBCT from pre-implant investigations. All included patients were healthy without any disorders affecting bone metabolism. We performed 13 measurements for each patient: 9 of height, width, and thickness (mm) and 4 of density (Hounsfield Units; HU). Fisher's exact test was applied to examine the association between two categorical variables, the Pearson correlation coefficient to measure the strength of linear relationship between two quantitative variables. We used the two-sample Student's t-test to compare mean symphysis height between men and women, the paired Student's t-test to compare mean lingual and buccal cortical thickness. For all tests, the threshold of significance was fixed at 5%. Results: Men and women significantly differed with regards to mean total symphysis height (p = 0.004) and the distribution of Cawood and Howell classifications (p = 0.033). Symphysis height was negatively correlated with mean density of cancellous bone (r = −0.453, p

Objectives: Many authors' have advocated a minimum of two implants to support a mandibular overdenture, but financial restraints specifically among the geriatric population in developing countries made this treatment plan economically difficult. Hence, this study was planned to assess the symphyseal (midline) single implant-assisted complete overdenture for patient satisfaction and masticatory performance. Materials and Methods: In this clinical study, 12 edentulous first-time denture wearers underwent placement of a single implant in the mandibular symphyseal region. After 1 week, new complete dentures were fabricated and delivered to the patients. Post 3 months, the denture was fixed with a nylon cap-ball attachment to the anchor implant. Patients were questioned about comparison in the level of satisfaction and complaint before loading the implant (control group) and after 1 week, 1 month, and 3 months. The implant-assisted overdenture was fabricated with the help of a questionnaire. Masticatory performance was calculated with the help of a bite force measuring device at the same time intervals. SPSS 17.0 statistical software was used to analyze the data. Results: It was found that single implant anchorage of the mandibular complete denture resulted in a significant increase (P < 0.05) in patient's subjective satisfaction and a decrease (P < 0.05) in complaints at the end of 3 months. There was a significant (P < 0.01) increase in bite force in implant overdenture after 3 months (5.459 kgf) as compared to that of the complete denture (3.406 kgf). Conclusion: Single implant-assisted overdenture can be an appropriate treatment modality to treat edentulousness in the geriatric population. It insinuates the remarkable improvement of prosthesis function and oral comfort with minor surgical procedures.

Objective: To find the pattern of isolated mandibular symphysis fracture and trends in management at a tertiary care hospital of Karachi, Pakistan. Study Design: Crossectional study. Setting: Department of Oral Surgery, Sir Syed Medical & Dental Hospital- Karachi, Pakistan. Period: January 2018 to December 2019. Material & Methods: Eighty one patients were selected on the basis of inclusion and exclusion criteria. They were diagnosed with isolated anterior mandibular fracture on basis of detailed history, thorough clinical examination and a radiologic investigation (OPG). Etiology of fracture and gender distribution was observed, fracture pattern was observed on basis of helmet wearing. Results: There was a male predilection with a male to female ratio of 4.3:1. Road traffic accident was the commonest cause. 82.7 % of patients were not wearing helmet at time of incidence and 69% from all patients had displaced mandibular fracture which resulted in derranged occlusion. Conclusion: Isolated anterior mandibular fractures is common in younger age group, with a male predilection. Most common etiologic factor is road traffic accident. Displaced fracture pattern is prevalent among patients who were not wearing helmet at time of incidence. [ABSTRACT FROM AUTHOR]

In the majority of cases anterior crossbite presents with vestibular inclination of the lower anterior teeth. Vestibular bone coverage in cases of protrusion is less thick. Development of recessions in this area depends on the anatomical features of the mandibular symphysis. Aim:To study the potential relationship between the inclination of the lower incisors and the parameters of the mandibular symphysis in patients with anterior crossbite using profile teleradiography and 3D cone beam computed tomography. Material and methods: We examined 20 patients with anterior crossbite aged 18-37 years (mean age 25.70 ± 5.95) who had not undergone orthodontic treatment. Profile teleradiographs and 3D cone beam computed tomography were performed on the included subjects. The inclination of the lower incisors and the parameters of the symphysis were measured (width at the narrowest and widest part and height – vestibularly and lingually). Results: Protrusion was prevalent in patients – 6 (30%) patients had retrusion and 14 (70%) had protrusion which is a significant difference of 40% (p = 0.26). The difference in the measurement of the inclination of the incisors using the two methods is not statistically significant (p = 0.128). Symphysis width measured on 3D cone beam computerized tomography amounts to 5.79 ± 0.74 mm in the narrow part and 15.41 ± 1.89 mm in the wide part. The height of the symphysis has a value of 24.19 ± 3.52 mm vestibularly and 25.20 ± 3.0 mm lingually. A significant positive correlation (Table 3) was found between the vestibular height of the symphysis and the inclination of the incisors in the mandible (r = 0.473, p = 0.035). A greater inclination of the incisors is associated with higher values of the vestibular height of the symphysis. Conclusion:We found a high level of consistency between teleradiographic and 3D cone beam tomographic measurements of the inclination of the lower incisors. Protrusion of lower incisors is associated with higher values of the symphysis measured vestibularly. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study was to evaluate mandibular symphyseal morphology and its relationship with uvulo-glossopharyngeal structures in patients who had a range of sagittal malocclusions.Methods: The study sample consisted of 100 patients who presented with Class I, Class II div. 1, Class II div. 2, or Class III malocclusions. Skeletal, dental, symphyseal, and uvulo-glossopharyngeal measurements were evaluated on cephalograms.Results: As the vertical growth of the mandibular symphysis increased, the ANB angle and the IMPA and soft palate length and thickness decreased, whereas, the SNB angle and RgnH increased significantly. In addition, as the symphysis inclination in relation to the mandibular plane increased, the IMPA and ANB angles increased, while tongue height decreased.Conclusion: Based on the findings of the present study, it can be concluded that there are relationships between mandibular symphysis morphology and the uvulo-glossopharyngeal structures and differences between sagittal skeletal malocclusions. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to assess the bony and soft tissue parameters at mandibular symphysis among skeletal Class III patients with different vertical growth patterns, using cone-beam computed tomography (CBCT)., Materials and Methods: CBCT images of 60 skeletal Class III non-growing patients were evaluated (mean age 24.9 ± 8.4 years). Study samples were classified into three facial types based on the mandibular plane angle (SN-MP angle): low, normal, and high angle. The bony and soft tissue parameters at the mandibular symphysis were evaluated., Results: Among hard tissue variables, symphysis and pogonion width were significantly narrower in the high-angle group (P < .05). The thickness of the buccal cortex at pogonion was also significantly thinner in subjects with high angles (P < .01). Symphysis height showed an increasing tendency from the low-angle to the high-angle group. However, no significant differences were found in chin width and height according to vertical patterns. Across all soft tissue measurements, the low-angle group exhibited the highest thickness, which gradually decreased in the high-angle group. Statistically significant differences in soft tissue thickness were observed at Menton (Me) and Gnathion (Gn) (P < .05). A significant negative correlation was observed between the SN-MP angle and the thickness of both hard and soft tissues., Conclusions: In skeletal Class III subjects, significant differences existed in both hard and soft tissues at the mandibular symphysis, depending on the vertical patterns. These results provide a comprehensive evaluation of symphyseal area, which can aid clinicians in identifying appropriate treatment approaches, especially for combined orthognathic and orthodontic treatment., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Many authors' have advocated a minimum of two implants to support a mandibular overdenture, but financial restraints specifically among the geriatric population in developing countries made this treatment plan economically difficult. Hence, this study was planned to assess the symphyseal (midline) single implant-assisted complete overdenture for patient satisfaction and masticatory performance. Materials and Methods: In this clinical study, 12 edentulous first-time denture wearers underwent placement of a single implant in the mandibular symphyseal region. After 1 week, new complete dentures were fabricated and delivered to the patients. Post 3 months, the denture was fixed with a nylon cap-ball attachment to the anchor implant. Patients were questioned about comparison in the level of satisfaction and complaint before loading the implant (control group) and after 1 week, 1 month, and 3 months. The implant-assisted overdenture was fabricated with the help of a questionnaire. Masticatory performance was calculated with the help of a bite force measuring device at the same time intervals. SPSS 17.0 statistical software was used to analyze the data. Results: It was found that single implant anchorage of the mandibular complete denture resulted in a significant increase (P < 0.05) in patient's subjective satisfaction and a decrease (P < 0.05) in complaints at the end of 3 months. There was a significant (P < 0.01) increase in bite force in implant overdenture after 3 months (5.459 kgf) as compared to that of the complete denture (3.406 kgf). Conclusion: Single implant-assisted overdenture can be an appropriate treatment modality to treat edentulousness in the geriatric population. It insinuates the remarkable improvement of prosthesis function and oral comfort with minor surgical procedures. [ABSTRACT FROM AUTHOR]

This study aimed to assess the anatomical variations of the mandibular symphysis in a normal occlusion population using cone-beam computed tomography (CBCT). This retrospective cross-sectional study evaluated 200 CBCT scans of patients aged =17 with class I occlusion, 1-3 mm overbite and overjet, and <3 mm crowding. The CBCT scans were obtained with NewTom 3G scanner with the exposure settings of 110 kVp, 1.2 mA, 5.4 s time, and six-inch field of view and saved in NNT Viewer. The anterior loop length, labial bone thickness, mandibular bone height at the symphysis, and cortical bone thickness at the right and left canine teeth and central and lateral incisors were measured and compared between males and females and different age groups using one-way ANOVA. The intra- and inter-observer agreements for all landmarks were ICC >0.9 (excellent). The mean length of the anterior loop in females was significantly greater than that in males (P=0.02). Different age groups had significant differences in cortical bone width at the site of the left canine (P=0.03) and vertical bone height at the site of the right central incisor (P=0.05). The majority of parameters related to the mandibular symphysis were greater in normal occlusion males than females. Preoperative CBCT assessment of the mandibular symphysis can greatly help in diagnosis and treatment planning as well as bone harvesting from this area. [ABSTRACT FROM AUTHOR]

Objective: The aim of this retrospective study was to evaluate the bone density (BD) at the mandibular symphysis according to horizontal and vertical patterns using cone-beam computed tomography (CBCT).Setting and Sampling: Three hundred nineteen untreated adults with a mean age of 24 years.Materials and Methods: CBCT images were converted into the lateral cephalometric images, and tracings were performed for categorizing the patients based on skeletal features. Cortical BDs at B point, pogonion (Pog), genion (Ge) and menton (Me), and cancellous BDs of the mandibular symphysis were measured using CBCT images. Statistical analyses were performed to evaluate the effects of horizontal and vertical skeletal patterns on BDs.Results: Females exhibited higher BD than males at the Me, Pog, Ge (P < .001). Hyperdivergent skeletal pattern showed significantly higher cortical BD than normovergent and hypodivergent skeletal patterns at Me (P < .001). Normovergent skeletal pattern showed significantly higher cortical BD than hypodivergent skeletal patterns at Me (P = .001). Class II skeletal pattern showed significantly higher cortical BD than Class I and III skeletal patterns at Me (P < .001) and Ge (P < .05). Class I skeletal pattern showed significantly higher mean cortical BD than Class III skeletal pattern at B point (P = .025). Cancellous BD was higher in Class III and hypodivergent skeletal patterns than others but showed no statistical significance.Conclusions: Significant differences were identified across various skeletal patterns. Several mandibular symphyseal landmarks showed statistically significant differences in BD at Me, B point and Ge, with Me having the most statistically significant findings. [ABSTRACT FROM AUTHOR]

Overdenture with single symphyseal implant is one of the useful clinical approach for elderly edentulous patients. We aimed to evaluate edentulous patients with regards to the relationship between dimensions, bone characteristics, cancellous densities, and cortical thickness of the mandibular symphyseal region using cone beam computed tomography (CBCT). We analyzed 103 CBCT from pre-implant investigations. All included patients were healthy without any disorders affecting bone metabolism. We performed 13 measurements for each patient: 9 of height, width, and thickness (mm) and 4 of density (Hounsfield Units; HU). Fisher's exact test was applied to examine the association between two categorical variables, the Pearson correlation coefficient to measure the strength of linear relationship between two quantitative variables. We used the two-sample Student's t-test to compare mean symphysis height between men and women, the paired Student's t-test to compare mean lingual and buccal cortical thickness. For all tests, the threshold of significance was fixed at 5%. Men and women significantly differed with regards to mean total symphysis height (p = 0.004) and the distribution of Cawood and Howell classifications (p = 0.033). Symphysis height was negatively correlated with mean density of cancellous bone (r = −0.453, p < 0.001). Mean lingual cortical thickness significantly differed from mean vestibular thickness (p < 0.001, paired Student's t-test). Present findings supported that symphyseal measurements are parameters that reflect the symphysis bone characteristics, and can guide the choice of a suitable implant design. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the overall bone thickness (OBT) and cortical bone thickness (CBT) of mandibular symphysis and to determine the optimal sites for the insertion of orthodontic mini implants. Cone-beam computed tomography (CBCT) images of 32 patients were included in this study. The sample was further categorized into three facial types: low-, average-, and high-angle. OBT and CBT were measured at the mandibular symphysis region. All measurements were performed at six different heights from the cementoenamel junction [CEJ] and at seven different angles to the occlusal plane. Analysis of variance (ANOVA) was used for statistical comparison and a p value less than 0.05 was considered statistically significant. Our results revealed that neither OBT nor CBT was influenced by age or sex, except for the observation that CBT was significantly greater in adults than in adolescents. OBT and CBT were significantly greater in low-angle cases than in average- and high-angle cases. Both OBT and CBT were significantly influenced by insertion locations, heights and angles, and their interactions. CBT and OBT were greatest at the location between two lower central incisors, and became greater with increases in insertion height and angle. Both recommended and optimal insertion sites were mapped. The mandibular symphysis region was suitable for the placement of orthodontic mini implants. The optimal insertion site was 6–10 mm apical to the CEJ between two lower central incisors, with an insertion angle being 0–60 degrees to the occlusal plane.

Objective: The objective is to compare new bone formation in critical defects in healthy, diabetic, and osteoporotic rats filled with hydroxyapatite (HA) alone and HA combined with simvastatin (SV). Materials and methods: A total of 48 adult female Sprague-Dawley rats were randomized into three groups (n = 16 per group): Group, 1 healthy; Group 2, diabetics; and Group 3, osteoporotics. Streptozotocin was used to induce type 1 diabetes in Group 2, while bilateral ovariectomy was used to induce osteoporosis in Group 3. The central portion of the rat mandibular symphysis was used as a physiological critical bone defect. In each group, eight defects were filled with HA alone and eight with HA combined with SV. The animals were sacrificed at 4 and 8 weeks, and the mandibles were processed for micro-computed tomography to analyze radiological union and bone mineral density (BMD); histological analysis of the bone union; and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2). Results: In all groups (healthy, diabetics, and osteoporotics), the defects filled with HA + SV presented greater radiological bone union, BMD, histological bone union, and more VEGF and BMP-2 positivity, in comparison with bone defects treated with HA alone. Conclusions: Combined application of HA and SV improves bone regeneration in mandibular critical bone defects compared with application of HA alone in healthy, diabetic, and osteoporotic rats. Clinical relevance: This study might help to patients with osteoporosis or uncontrolled diabetes type 1, but future studies should be done. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed the impact of mandibular bone height on masticatory performance following treatment with a mandibular conventional denture (CD) or implant-retained overdenture (IOD). Materials and Methods: Evaluation of masticatory performance in 63 participants was made with original CDs and 6 months after treatment completion with new dentures; 25 patients received a mandibular CD and 38 received a mandibular IOD. Anterior ridge height at the mandibular symphysis was determined on lateral cephalograms to provide subgroups of low (= 21 mm), moderate ( > 21 mm, < 28 mm), and high (= 28 mm) ridge height for both CDs and IODs. Masticatory performance tests on the preferred chewing side (PS) and swallowing threshold tests were made with peanuts and carrots. Results: Analysis of variance was used for comparisons of mean change in performance after treatment with study dentures for the 3 bone height groups; this indicated significant differences between the CD and IOD for PS masticatory performance with peanuts (P = .05) and carrots (P = .03). Post hoc tests found significant mean differences between the CDs and IODs with peanuts (P = .008) and carrots (P = .01) only in the low bone height group. Although no significant differences were found in swallowing threshold performance, the mean change scores for subjects with low bone height were greater with the IODs than those with CD for swallowing threshold performance, strokes, and time. Discussion: It is suggested that only in patients with advanced ridge resorption is the mandibular IOD more likely than a CD to result in improvements in masticatory performance. Conclusion: The study indicated that treatment with a mandibular IOD may improve masticatory performance only in persons with a less than adequate mandibular ridge. [ABSTRACT FROM AUTHOR]

Vertical augmentation of the alveolar ridge is intended to restore resorbed alveolar ridges. This procedure is important for the placement of dental implants in a favorable position and also to enhance restoration esthetics. This article presents an approach for vertical ridge augmentation in the anterior maxilla utilizing symphyseal bone cores. A patient presented with 2 localized bony defects around the maxillary lateral incisors. Following extraction of these teeth, vertical bone defects of 7 mm on the right and 6 mm on the left were observed in relation to the cementoenamel junction of the adjacent teeth. Two bone cores were harvested from the mandibular symphysis using a trephine. These bone cores were tapped into 2 predrilled osteotomy sites with corresponding diameters until stabilization was achieved. The 2 sites were grafted with demineralized freeze-dried bone allograft and a titanium-reinforced expanded polytetrafluoroethylene membrane. After 5 months, the membranes were removed and vertical ridge augmentation of 5 mm on the right and 4 mm on the left was observed. The width of the ridge was increased as well. Two implants were placed in favorable positions, restored after 6 months, and followed successfully for 1 year after loading. This technique represents a viable approach for augmentation of deficient alveolar ridges prior to the placement of dental implants. [ABSTRACT FROM AUTHOR]

Little information exists to define the minimum number of implants required for sufficient anchorage of mandibular overdentures. To date, 2 implants placed in the interforaminal region have been considered the minimum. The aim of this study was to examine whether a single symphyseal implant would suffice for adequate anchorage of a mandibular complete denture in elderly patients (octogenarians), and whether this surgically, prosthetically, and financially simple concept would also satisfy patients needing replacement of the mandibular dentition. Nine patients with a mean age of 82.2 years underwent placement of a single symphyseal endosseous implant and anchorage of a complete denture using a ball attachment. Standardized recall examinations, including patient response and inspections of the peri-implant soft tissue and bone conditions, were carried out at 3- to 6-month intervals for a period of 1½ years. It was found that anchorage with a single implant led to both a significant improvement in patients' subjective satisfaction (P < .01) and a significant reduction in reported symptoms (P < .01). During the observation phase, pocket depth and bone resorption initially increased around implants but stabilized after the sixth month. Denture management (placement and removal) also improved during the recall period (P < .01). The results of this study indicate that oral rehabilitation by mandibular complete dentures anchored on a single implant can be considered an economical therapeutic alternative to a conventional mandibular complete denture for very old (octogenarian) patients. [ABSTRACT FROM AUTHOR]

Partially edentulous patients with alveolar defects contraindicating implant placement were treated with bone grafts obtained from the mandibular symphysis. Complications encountered were minor and uneventful. Evaluation 4 months after surgery revealed minimal graft resorption, thus implant placement was possible in all potential sites. Advantages of the symphysis graft include easy access, availability of greater quantities of bone over other intraoral donor sites, low morbidity, no hospitalization, minimal discomfort, no alteration in ambulation, and no cutaneous scar. Compared with other bone regenerative methods for implant placement, a superior quality of bone was found and a shorter healing period is required. Results of this preliminary clinical investigation demonstrate that chin grafts offer a viable alternative for reconstruction of alveolar defects prior to dental implant placement. [ABSTRACT FROM AUTHOR]

Introduction: Mandible is one of the most commonly fractured bones in maxillofacial trauma. Mandibular symphysis is a common site of mandibular fractures. Compare to conventional miniplates, three dimentional plates were found more effective in terms of post operative occlusion, post operative mobility of reduced fractured segments and the degree of anatomic reduction. Objectives: Compare the conventional 2.0mm mini plates versus 3D mini plates in the fixation of isolated mandibular symphysis fractures. Study Design: Interventional study. Setting: Oral & Maxillofacial Surgery Department, Abbasi Shaheed Hospital Karachi. Period: Two years from 1st January 2013 to 2nd January 2015. Material & Methods: One hundred and fifty four patients were randomly selected and allocated into two groups. Group'I' in which patients were treated with conventional mini plates and group'II' where patients were treated with 3D mini plates. Results: Mean (+SD) age of patients was 29.53 (±7.88) years. Among 154 patients in this study, majority (75.3%) of cases had age 20 - 35 years. Majority, 124 (81.2)were males and 29 (18.8%) were females. In Group I, anatomic reduction at 3 month post-operative was observed in 30 (39%). In Group II (3D Plates) at 3 months post-operatively, ideal molar relationship was higher (89.6% Vs. 98.7%; p-value = 0.016), fracture mobility was lower (14.3% Vs. 2.6%; p-value = 0.009) and higher anatomic reduction. Conclusion: Three dimensional miniplates are more effective compared to conventional miniplates. [ABSTRACT FROM AUTHOR]

Background and Aim: Maxillofacial trauma is very common in all unforeseen events and the unique position of the mandible on the face makes it vulnerable. It is therefore, one of the most commonly fractured facial bones. The aim of this study is to compare 3-Dimensional versus 2-Dimensional Stainless steel miniplates for open reduction and fixation of mandibular symphysis and parasymphysis fracture. Methods: Patients with symphysis and parasymphysis fractures of mandible (unilateral/bilateral) were selected. All patients were treated and observed by the same surgeon. Routine investigations were carried out. Results: There is no statistically significant difference between three dimensional miniplate and twodimensional miniplate osteosynthesis in the open reduction and internal fixation of mandibular symphysis and parasymphysis fractures. Clinically, three-dimensional miniplates were found to be better than two-dimensional miniplates in terms of cost, ease of surgery and operative time. Conclusion: Three-dimensional miniplates were unfavorable for cases where fracture line was oblique and in close proximity to the mental foramen, where they were difficult to adapt and there were more chances for tooth-root damage and inadvertent traction of the mental nerve. Studies with larger sample size are recommended to correlate the findings of the present study for their wider use in clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to (1) analyze the relationships between mandibular symphysis characteristics (height, prominence, inclination, concavity, and convexity) and facial pattern, skeletal class, lower incisor position, and sex, and (2) determine the associations between the symphysis soft tissue dimensions and the underlying osseous structures.Methods: Cone-beam computed tomography (CBCT) images were selected for 385 patients (206 women and 179 men). The patients were classified according to their skeletal class and vertical pattern. The lower incisor inclination (IMPA) was recorded. Twelve measurements were taken for each mandibular symphysis using Invivo5 software (Anatomage, San Jose, CA, USA).Results: Symphyseal measurements were larger in males than in females. Skeletal Class II and III hyperdivergent patients showed the highest symphysis height values. Hypodivergent individuals showed lower symphysis convexity angles. Concavity of the symphysis was greater for Class II hyperdivergent patients. Lower incisor inclination showed a positive correlation with symphysis concavity and inclination. Moderate and weak correlations were found between hard tissue and soft tissue parameters.Conclusions: Only a few characteristics of symphysis morphology depend on sex, incisor position, skeletal class, and vertical pattern. More significant relationships are found when the vertical pattern and skeletal class are analyzed in combination. The shape of the symphysis soft tissue is not directly correlated with the underlying skeletal structures. [ABSTRACT FROM AUTHOR]

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Background A key factor in planning orthodontic treatment is the position of the lower incisor, which must keep a correct relationship with its underlying bony support, the mandibular symphysis. Objectives To determine whether there is a statistically significant relationship among the position of the lower incisor, Holdaway ratio, symphyseal morphology, and facial pattern. Methods A total of 100 patients were randomly selected from the records of the Master in Orthodontics and Dentofacial Orthopedics (University of Seville, Spain). Measurements were made manually on pretreatment cephalograms by two operators using Aki analysis to assess the height/width ratio (H/A), mandibular plane with point B–Menton, and the retro-occlusion of the Jarabak/MSE analysis to determine the facial biotype. A descriptive analysis of the data was made evaluating the possible correlations between the Holdaway ratio and H/A, and the Holdaway ratio and mandibular angle. Results The correlation among facial pattern, H/A, and the Holdaway ratio proved significant ( P < 0.05). Conclusions Symphyseal morphology is correlated to facial growth pattern and lower incisal inclination. There are biological limits to inclination movements of the lower incisor in narrow symphysis, which are usually found in vertical growth patterns. [ABSTRACT FROM AUTHOR]