Mandibular Symphysis Research Articles

A Fossil Dolphin from the Oi Formation, Ichishi Group (Late Early Miocene) in Japan

Narrow dolphin mandibles with an elongate mandibular symphysis from the Oi Formation, Ichishi Group (late early Miocene) of Tsu City, Mie Prefecture, Japan is reported. The specimen shows different morphologies from “Eurhinodelphis” minoensis and Ninjadelphis ujiharai, which were reported from late early Miocene sediments of the same region. This new record expands our knowledge of lower Miocene odontocetes from Japan and indicates that at least three odontocetes are represented in the Mizunami and Ichishi Groups.

Exérese de cementoblastoma benigno em região de sínfise mentoniana – relato de caso

Cementoma or cementoblastoma is a rare occurrence lesion, which can occur both in the mandible and in the maxilla. It affects children and young adults, with the area most affected by the premolars and molars. The diagnosis is differentiated with osteoblastoma, odontoma, condensing osteitis, cement-ossolifying fibroma, periapical cement dysplasia and hypercementosis. The histopathological aspect is of a mineralized mass similar to the cementum associated with a fibrovascularized stroma, interposed by cementoblasts. This article aimed to report a clinical case of symptomatic and infected benign cementoblastoma, located in the region of the mandibular symphysis in a 65-year-old female patient, whose treatment underwent excision under local anesthesia, with healing promoted by second intention due to the infectious process installed The treatment undertaken culminated in the cure of the pathological process.

Surgical Reduction of Symphysis Fracture and Spontaneous Repositioning of the Mandibular Condyle: A Case Report

The condylar process is a more fragile area, which is usually fractured by indirect trauma. The objective of this study is to report the case of a 10-year-old patient who presented to the Maxillofacial Surgery and Traumatology Service of the Regional Hospital of Vale do Paraíba, in Taubaté-SP, Brazil. Physical examination revealed limited mandibular movement with painful symptoms, crossbite, and upper incisor avulsion. A face tomography showed a fracture of the mandibular symphysis (right side) and a fracture of the left condyle. Surgical reduction of the mandibular symphysis fracture was performed. After exposure and reduction of bone segments, maxillomandibular block, rigid internal fixation and conservative treatment for condyle fracture were performed. A soft liquid diet and weekly outpatient follow-up was adopted for the first two months. After 15 days of surgery, the patient had mild edema, slight limitation in mouth opening, sutures without dehiscence and without signs of infection. In the first control tomography, the treated fracture was adequately reduced and the fractured condyle remained with medial displacement in the glenoid cavity. After one year, on physical examination, the patient presented satisfactory dental occlusion, preserved mandibular movements and no signs of nerve damage. The tomography showed the fracture consolidated, and the left mandibular condyle well positioned in the glenoid cavity. After two years, the third tomography was performed, showing remodelling of the left mandibular condyle.

Three-dimensional evaluation of dental decompensation and mandibular symphysis remodeling on orthodontic-surgical treatment of Class III malocclusion

The purposes of this research were to identify the buccolingual inclinations of the mandibular teeth and the mandibular symphysis remodeling that result from the orthodontic decompensation movement. The sample consisted of 30 adults with Class III dentofacial deformity, who had presurgical orthodontic treatment. Three-dimensional images were generated by cone-beam computed tomography scans at 2 different times (initial and before orthognathic surgery). Three-dimensional virtual models were obtained and superimposed using automated voxel-based registration at the mandible to evaluate B-point displacement, mandibular molar and incisor decompensation movement, and symphysis inclination and thickness. The 3-dimensional displacements of landmarks at the symphysis were quantified and visualized with color-coded maps using 3D Slicer (version 4.0; www.slicer.org) software. The measurements showed high reproducibility. The patients presented mandibular incisor proclination, which was consistent with the movement of tooth decompensation caused by the presurgical orthodontic treatment. Statistically significant correlations were found between the inclination of the mandibular incisors, symphysis inclination, and B-point displacement. Regarding the thickness of the symphysis and the inclination of the incisors, no statistically significant correlation was found. The buccolingual orthodontic movement of the mandibular incisors with presurgical leveling is correlated with the inclination of the mandibular symphysis and repositioning of the B-point but not correlated to the thickness of the symphysis.

Ridge augmentation of Class III ridge defect using piezosurgery with autogenous chin graft followed by implant placement: A 6 months follow-up interventional study

Background: Tooth loss occurs due to periodontal disease, extensive dental caries, and fracture of teeth after a dento-alveolar trauma, cyst and tumours of odontogenic and non-odontogenic origin. Following loss of teeth, alveolar ridge resorption becomes an unwanted but unavoidable consequence. In order to restore the lost bone and replace the teeth with implants, ridge augmentation procedures are done. The present study aimed at restoring the class III ridge defect using piezosurgery with autogenous block bone graft procured from mandibular symphysis region. Materials and methods: A total number of 10 healthy patients with Class III ridge defect in maxillary anterior teeth region were enrolled for the study. The donor and defect sites were pre-surgically analysed using Cone-Beam Computed Tomography (CBCT), preclinical models and ridge mapping.The implant site width and height were assessed intra-operatively during the surgery and at re-entry after 6 months. The autogenous block bone grafts were procured from mandibular chin region using piezo-electric device and placed at the recipient site. At the 6 months re-evaluation, both clinical and radiographic parameters were assessed using CBCT of the recipient site. Implants were placed at two-stages and followed-up up to 6 months. Results: Clinical measurements showed that the mean horizontal bone gain and vertical bone gain was noted to be 3.21±0.24 mm and 2.18±0.32 mm respectively, by the end of 6 months follow-up. No major complications were presented at the recipient as well as donor sites. Piezoelectric surgery provided clean, bloodless field during the procedure and minimal post-operative discomfort to the patients. Conclusion: The results of the present study suggests that, class III ridge defects can be successfully augmented using piezo-surgery using autogenous bone grafting from the mandibular symphysis region. Also, delayed implant placement may provide satisfactory functional and aesthetic outcomes on the long term. Keywords: Ridge augmentation; chin graft; Piezosurgery; dental implants

Sesamoids in Caudata and Gymnophiona (Lissamphibia): absences and evidence.

An integrative definition of sesamoid bones has been recently proposed, highlighting their relationship with tendons and ligaments, their genetic origin, the influence of epigenetic stimuli on their development, and their variable tissue composition. Sesamoid bones occur mainly associated with a large number of mobile joints in vertebrates, most commonly in the postcranium. Here, we present a survey of the distribution pattern of sesamoids in 256 taxa of Caudata and Gymnophiona and 24 taxa of temnospondyls and lepospondyls, based on dissections, high-resolution X-ray computed tomography from digital databases and literature data. These groups have a pivotal role in the interpretation of the evolution of sesamoids in Lissamphibia and tetrapods in general. Our main goals were: (1) to contribute to the knowledge of the comparative anatomy of sesamoids in Lissamphibia; (2) to assess the evolutionary history of selected sesamoids. We formally studied the evolution of the observed sesamoids by optimizing them in the most accepted phylogeny of the group. We identified only three bony or cartilaginous sesamoids in Caudata: the mandibular sesamoid, which is adjacent to the jaw articulation; one located on the mandibular symphysis; and one located in the posterior end of the maxilla. We did not observe any cartilaginous or osseous sesamoid in Gymnophiona. Mapping analyses of the sesamoid dataset of urodeles onto the phylogeny revealed that the very conspicuous sesamoid in the mandibular symphysis of Necturus beyeri and Amphiuma tridactylum is an independent acquisition of these taxa. On the contrary, the sesamoid located between the maxilla and the lower jaw is a new synapomorphy that supports the node of Hydromantes platycephalus and Karsenia coreana. The absence of a mandibular sesamoid is plesiomorphic to Caudata, whereas it is convergent in seven different families. The absence of postcranial sesamoids in salamanders might reveal a paedomorphic pattern that would be visible in their limb joints.

Study of mandibular thickness in dentulous and edentulous mandibles

There are several methods of reconstruction for lower human jaw, but the most common and safest is using plates and screws. The size of the lower jaw bone varies from person to person, therefore plates and screws are available in different sizes.1 A critical buccal bone thickness of 2 mm is recommended to prevent vertical resorption. A minimum bone thickness of 6 mm would be required for successful placement of a standard-sized ±4-mm-diameter implant.2 In the present study Mandibular Body Thickness (MBT) was studied in 110 dry mandibles to evaluate the ideal length of dental implants used during the corrective procedures on the mandibular alveolar process. All the mandibles in our study had adequate bone thickness needed for implant placement without traumatizing the sublingual artery. Keywords: Mandible, Symphysis menti, Premolar, Molar, Reconstruction, Maxillofacial surgery.

Lower jaw morphology of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar

ABSTRACT The lower jaw of the holotype of Adalatherium hui, from the Late Cretaceous of Madagascar, is the most complete yet known for a gondwanatherian mammal. It reveals for the first time the morphology of the character-rich ascending ramus of the dentary in a gondwanatherian. Each half of the lower jaw is composed of only one bone, the dentary, which is short and deep and houses only five teeth: an enlarged, procumbent incisor and four postcanine teeth. In comparable parts of its anatomy, the dentary of Adalatherium is strikingly similar to that of Sudamerica but differs slightly from that of Galulatherium (conformation anterior to first postcanine, mental foramen position), the only two other gondwanatherians represented by complete horizontal rami. Among other Mesozoic mammaliaform taxa, the dentary of Adalatherium is most similar to those of the largely Laurasian group Multituberculata, most notably in absence of postdentary trough and Meckelian sulcus; presence of short, deep dentary with sizable diastema and articulating with squamosal via mediolaterally narrow condyle that continues onto posterior surface (i.e., no distinct peduncle); possession of much reduced dentition; absence of angular process; possession of large pterygoid fossa and pterygoid shelf, ventral surface of which is flat; absence of coronoid bone; and possession of unfused mandibular symphysis. Most of these features are clearly derived and stand in stark contrast to the much more plesiomorphic morphology exhibited by the lower jaw of the haramiyaviid Haramiyavia. The lower jaws of euharamiyidans, although derived in their own right, are also relatively plesiomorphic.

Miniplate-anchored maxillary protraction in adolescent patients with cleft lip and palate: A literature review of study design, type and protocol, and treatment outcomes.

To review the study design, type, protocol, and treatment outcomes of miniplate-anchored maxillary protraction (MAMP) in adolescent patients with unilateral or bilateral cleft lip and palate. Five retrospective and two prospective studies (n=138 patients) were selected as per the inclusion criteria. The study design, type, protocol of MAMP and the amount of skeletodental change were investigated. Two studies adopted type 1 (two miniplates at the infrazygomatic crest with a facemask), four studies adopted type 2 (four miniplates at the infrazygomatic crest and mandibular symphysis and use of intermaxillary elastics), and one study compared the two types. The mean start age was older than 10years except one study. The mean duration was less than 1year in two studies, between 1 and 2years in three studies, and more than 2years in two studies. The type 1 used 500g/side for 12-14h/d, and the type 2 used three increase methods (100, 200, 250g/side; 75, 150, 250g/side; 150, 200, and 250g/side) for 24h/d. The ranges of A point advancement were 0.5°-4.2° in ΔSNA and 1.7-5.6mm in ΔA-vertical reference plane, respectively. The ranges of rotation of the palatal plane, occlusal plane, and mandibular plane were -1.5° to 2.0°, -2.0° to 2.0°, -1.5° to 3.2°, respectively. The increase of overjet was ranged from 2.3 to 5.8mm. The MAMP therapy is effective for the correction of maxillary hypoplasia in adolescent cleft patients despite different types and protocols.

MORPHOGENESIS PECULIARITIES OF THE SUPRAHYOID REGION IN THE PREFETAL PERIOD OF HUMAN OTOGENESIS

Elucidation of the features of morphogenesis and topographic changes of suprahyoidregion (SHR) of the neck and its structures in the dynamics of human intrauterinedevelopment (IUD) remains a relevant area of morphological research. Refined,comprehensive data on gender, age and constitutional features of the structure andtopography of organs and structures of the SHR of the neck during the prenatal periodof human ontogenesis will make it possible to develop new criteria for the interpretationof medical diagnostic imaging data, the degree of fetal viability, improve existing anddevelop new methods of surgical correction of congenital neck defects.Purpose of the work: to clarify the morphometric features of the suprahyoid region ofthe neck in the prefetal period of human ontogenesis.Material and methods. Thirty preparations of human prefetuses of 14.0-80.0 mm parietococcygeal length (PCL) (7-12th weeks of IUD) were studied using a complexof modern methods of morphological research: anthropometry, morphometry, threedimensional reconstruction and statistical analysis. The morphometric parametersof SHR were determined: width (distance between the inner surfaces of the condylarprocesses of the mandible), anteroposterior length (distance from the anterior surfaceof the hyoid bone to the lower edge of the mental symphysis), lateral length (length ofthe lateral border of the SHR – distance from the inner surface of the angle of mandibleto the lower edge of the mental symphysis), the anterior angle of the SHR (the anglebetween the lateral borders of the SHR).Results. On the basis of the obtained digital indicators of the main morphometricparameters of human SHR in the dynamics of the prenatal period of IUD the criticalperiods of development of the region were clarified and mathematical functions thatdescribe the normal course of organogenesis of SHR were created, which can be usefulfor creating diagnostic algorithms for the norm when carrying out prenatal diagnosticsand monitoring the state of the fetus. It has been established that the 9-10th week of IUDis a critical period in the development of SHR, since during this time, intensive growthprocesses occur, which are manifested by a sharp change in the size of the organ, andthis can lead to the appearance of variants of the structure and possible congenitaldefects of the SHR and the dental-maxillary apparatus in general.Conclusions.1. At the 10th week of the prefetal period of IUD, there is an accelerated increase in theanteroposterior size of the LAP (y = -6.3851 + 1.041 * x; r = 0.9374; p = 0.00001).2. At the 11th week of the prefetal period of IUD, there is an accelerated increase in thelateral length of the SHR (y = -6.1289 + 1.1277 * x; r = 0.8891; p = 0.00001).3. During the clarification of the regularities of the dynamics of changes in the widthof the SHR, it has been found that at the beginning of the prefetal period of the IUD,the growth rates of the indicator are slow, but from the 9th week of IUD, its acceleratedgrowth is observed (y = -4.5904 + 1.1074 * x; r = 0.8662; p = 0.00001).4. Features of the change in the value of the anterior angle of SHR in the prefetal periodof human ontogenesis demonstrate a general tendency towards its decrease during thisperiod of development – from 90.18±0.55° (7th week) to 82.12±1.17° (12th week), butafter a sharp decrease in this angle until the end of the 8th week of the development(79.32±1.03°), its intensive growth begins during the 9th week and until the end of theprefetal period (y = 93, 8224 – 0.9577 * x; r = -0.4140; p = 0.0229).

Peculiarities of development of the suprahyoid muscles of the neck at an early period of human ontogenesis

Objective – of the work is to clarify the sources of germs and find out the chronological sequence of morphogenesis of the muscular structures of the suprahyoid triangles of the anterior cervical region in the embryonic and prefetal periods of human ontogenesis.Material and methods. 25 series of consecutive histological sections of human embryos and prefetuses aged from 5 till 12 weeks of development (6.0-80.0 mm parietal-coccygeal length (PCL)) using a complex methods of morphological examination (anthropometry, morphometry, microscopy, three-dimensional computer reconstruction and statistical analysis) were studied.Results. The rudiment of digastric muscle was first detected in 7-week-old prefetuses (15.5-16.0 mm PCL). The medial surface of Meckel’s cartilage is the site of attachment of the superior belly of the digastric muscle. At the 12th week of intrauterine development, the digastric muscle finally acquires its definitive attachment to the internal surface of the body of mandible. The rudiment of the mylohyoid muscle was first detected in 6-week-old embryos (10.0-12.0 mm PCL). The place of its attachment begins near the mental symphysis, the attachment of the muscle to the anlage of the hyoid bone was detected only at the end of the 7th week of intrauterine development (prefetuses 19.0-20.0 mm PCL). The anlage of the geniohyoid muscle was first determined in the 6-week-old human embryos. In prefetuses of 15.5- 40.0 mm PCL, geniohyoid muscle begins on the medial surface of Meckel’s cartilage, and from the 12th week of intrauterine development (prefetuses 75.0-77.0 mm PCL), the muscle attachment is localized on the internal surface of the body of mandible. The genioglossus muscle is found on the internal and caudal surfaces of Mekel’s cartilage, but from the middle of the 12th week of intrauterine development the site of its attachment moves to the medial-caudal surface of the body of mandible.Conclusions. 1. The anlages of all muscles that delimit the boundaries of the suprahyoid triangles of the neck were identified at the beginning of the 7 th week of intrauterine development (prefetuses 15.5-16.0 mm PCL). 2. The suprahyoid muscles attach to the medial surface of Meckel’s cartilage, but during the 8-11th weeks of intrauterine development, the attachment sites gradually move to the bony edges of the mandible, which cover Meckel’s cartilage. 3. In the prenatal period of development, bundles of the mylohyoid muscle leave the anterior region of the mental symphysis free. 4. In human prefetuses, only the geniohyoid and mylohyoid muscles were attached to the hyoid bone.

Basal Extended Mentoplasty.

The chin is one of the most visible facial structures. Chin surgery, was initially described, for, the treatment of facial abnormalities, advancing the mandibular symphysis; achieved anterior displacement of the base of the tongue showing some value in the treatment of snoring and obstructive sleep apnea, and achieved adequate lip competence. We designed the Basal Extended Mentoplasty (BEM) based on the needs of patients orthodontically compensated, but dissatisfied with the appearance of his face as well as upper airway problems looking for a solution to this, design and planning the advances of the chin. Patients operated in the service of Maxillofacial Surgery, Specialist Hospital, "Dr. Bernardo Sepulveda "XXI Century National Medical Center, during the period of 2015-2019, orthodontically compensated patients, with labial incompetence and Class II skeletal. Sixty-five patients were operated during this period, and eight cases are presented. Lip competition, osseointegration of the segments is observed, with a proper projection of the lower third, no nerve or vascular damage in the area. The design of the osteotomy is for orthodontically compensated patients with labial incompetence and Class II skeletal, giving a result mandibular lengthening. The BEM achieved adequate lip competence demonstrated by an interlabial gap of 0mm, achieved adequate osseous consolidation of the fracture site with a more harmonious facial balance and profile, without nerve or vascular damage with spectacular results.

Comparison of the mechanical properties of biodegradable and titanium osteosynthesis systems used in oral and maxillofacial surgery

To guide the selection of osteosynthesis systems, this study compared the mechanical properties of biodegradable and titanium osteosynthesis systems. SonicPins Rx and xG were subjected to pull-out tests. Additionally, 15 biodegradable (Inion CPS 2.0 and 2.5 mm; LactoSorb 2.0 mm; Macropore 2.0 mm; Polymax 2.0 mm; BioSorb FX 2.0 mm; ResorbX 2.1 mm; Osteotrans-MX 2.0 mm with plate thicknesses 1.0 and 1.4 mm; SonicWeld Rxplate/Rxpins, xGplate/Rxpins and xGplate/xGpins 2.1 mm without and with tapping the burr hole) and six titanium (CrossDrive (2006), CrossDrive (2018), MaxDrive; all 1.5 and 2.0 mm) straight, four-hole osteosynthesis systems were evaluated. All systems were subjected to tensile, bending and torsion tests. Pull-out loads of the SonicPins were comparable (P = 0.423). Titanium systems’ tensile loads were higher than biodegradable systems (P < 0.001). CrossDrive (2018) and MaxDrive systems’ tensile and torsional stiffness were lower, accompanied with higher ductility, than corresponding CrossDrive (2006) systems (P < 0.001). Bending stiffness of 1.5 mm titanium systems was comparable to, and of the 2.0 mm systems higher than, all biodegradable systems (P < 0.001). Regarding biodegradable systems, Inion CPS 2.5 mm had highest tensile load and torsional stiffness, SonicWeld 2.1 mm highest tensile stiffness, and BioSorbFX 2.0 mm highest bending stiffness (P < 0.001). On the basis of the results of this study, the CrossDrive (2018) and MaxDrive 1.5 mm titanium systems are recommended for midface fractures (e.g., zygomatic or maxillary fractures) and osteotomies (e.g., Le Fort I osteotomy), and the CrossDrive (2018) and MaxDrive 2.0 mm titanium systems for mandibular fractures and osteotomies when a titanium osteosynthesis system is used. When there is an indication for a biodegradable osteosynthesis system, the SonicWeld 2.1 mm or BioSorbFX 2.0 mm are recommended for midface fractures and osteotomies, and the Inion CPS 2.5 mm biodegradable system for mandibular osteotomies and non-load bearing mandibular fractures, especially when high torsional forces are expected (e.g., mandibular symphysis fractures).

Combined Symphyseal and Condylar Fractures: Considerations for Treatment in Pediatric Patients

BACKGROUND: Combined symphyseal-condylar mandible fractures represent a unique, unstable injury pattern that can cause significant morbidity in pediatric patients. However, this particular mandibular injury pattern has not been well characterized in children. Given the complex biomechanics of the mandibular symphysis and the importance of the condyles in long-term mandibular growth and occlusal development, focused study of pediatric symphyseal-condylar fractures is important.1,2 This study investigated the etiology and management of symphyseal-condylar fractures in pediatric patients, in order to provide treatment recommendations to improve long-term outcomes. METHODS: This was a retrospective cohort study of pediatric patients with symphyseal-condylar mandibular fractures both at our institution between 1990 and 2019 and nation-wide (identified in the Healthcare Cost and Utilization Project Kid Inpatient Database) between 2000 and 2016. Two-tailed Mann–Whitney U and Fischer’s exact analyses were used to compare demographic and clinical factors as well as incidence of complications between patients in each dentition stage in our institutional dataset. Also, multiple logistic regression with forward stepwise selection of predictor variables was used to generate adjusted odds ratios for complications, and a treatment algorithm was proposed. National data on pediatric symphyseal/condylar fractures between 2012 and 2016 abstracted from Healthcare Cost and Utilization Project Kid Inpatient Database were used to confirm recommendations in the proposed treatment algorithm using chi square analyses. Additionally, a logistic regression model was used to evaluate the proposed treatment algorithm, by predicting odds of complications based on adherence or nonadherence to the algorithm for patients in each dentition stage. Concordance statistics were used to evaluate model robustness. RESULTS: Twenty-one patients at our institution and 1,708 national database patients met inclusion criteria. At our institution, 26.7% of deciduous dentition patients underwent ORIF, 40% underwent closed treatment (MMF), and 33.3% were treated with soft diet. All mixed dentition patients underwent either ORIF or closed treatment (MMF); all permanent dentition patients underwent ORIF. In the national cohort, most permanent dentition patients (88.7%) underwent ORIF, while most mixed dentition patients (79.2%) underwent closed treatment. Among deciduous dentition patients in the national cohort, 53.5% patients were treated with soft-diet and 38% with closed treatment. At our institution, the overall post-treatment complication rate was 62.5% among ORIF patients, 14.3% among closed treatment patients, and 16.7% among patients treated with soft diet. The most common complications were temporomandibular joint dysfunction (50%) and malocclusion (37.5%). A treatment algorithm was developed using study data; algorithm adherence significantly decreased odds of complications (odds ratio, 0.03; 95% CI, 0.001–0.6; P = 0.03). CONCLUSIONS: Symphyseal-condylar fractures were associated with substantial morbidity in children. Using the data from both our institution as well as from review of a national database, we proposed a treatment algorithm, stratified by dentition stage, in order to guide treatment for children who present with this complex fracture type. REFERENCES: 1. Wolfswinkel EM, Weathers WM, Wirthlin JO, et al. Management of pediatric mandible fractures. Otolaryngol Clin North Am. 2013;46:791–806. 2. Cole P, Kaufman Y, Hollier L. Managing the pediatric facial fracture. Craniomaxillofacial Trauma Reconstr. 2009;2:077–083.

Mandibular symphysis dimensions in different sagittal and vertical skeletal relationships.

BackgroundThe aim of this cross-sectional study was to compare the dimensions of mandibular symphysis (MS) between gender and the different sagittal and vertical skeletal relationships.Material and MethodsPre-treatment records of orthodontic patients were divided according to gender, sagittal (Class I, II and III) and vertical (decreased, average and increased mandibular plane [MP] angle) skeletal relationships. Measurements of MS parameters were performed on lateral cephalograms using IMAGEJ software. Comparisons between MS parameters and gender and the different skeletal relationships was performed using multifactorial and one-way ANOVA, and independent sample t-tests.ResultsA total of 104 records (25 males and 79 females) fulfilled the inclusion criteria. Males had significantly greater MS surface area, dentoalveolar length, skeletal symphysis length, total symphysis length, vertical symphysis dimension and symphysis convexity (p < 0.05). Skeletal Class II patients had significantly greater dentoalveolar and skeletal symphysis lengths while Class III had greater chin length, vertical symphysis dimension and symphysis convexity (p < 0.05). Patients with decreased vertical dimension had greater skeletal symphysis length (p = 0.026) and those with an average vertical relationship had greater chin length (p < 0.001).ConclusionsThe morphology of the mandibular symphysis is affected by gender, sagittal and vertical skeletal patterns. Males had increased mandibular symphysis surface area and linear dimensions. Class II patients had greater dentoalveolar length. Chin length was greater in patients with an average MP angle.

Correlation Between Gonial Angle And Mandibular Symphysis Width In South Indian Dravidian Population

Mandibular growth pattern (MGP) prediction plays an important role in orthodontic treatment planning. This study sought to assess the mandibular symphyseal width in adolescents with different mandibular growth patterns (MGPs) so as to see whether a correlation exists. This study was conducted on 90 lateral cephalograms of patients aged between 10 and 16 years. The subjects were divided into normo-divergent, hypodivergent and hyperdivergent subgroups based on the gonial angle. The symphyseal measurement included width or depth of the mandibular symphysis according to Akietal study. He suggested that a mandible with anterior growth direction was associated with a large depth of the symphysis. In contrast, a mandible with a posterior growth direction was associated with a small depth of symphysis. To assess the correlation between mandibular symphyseal width and mandibular growth pattern, Pearson’s correlation test was done. Correlation is significant at the 0.01 level (2 tailed). A P-value which is less than 0.05 was considered statistically significant. The mandibular symphyseal width was found to be strongly associated with the MGP. It can be inferred from the results that in vertical growth pattern, as the gonial angle increases, symphyseal width decreases and in horizontal growth pattern, as the gonial angle decreases, symphyseal width increases. Also, in vertical growth pattern subjects, the mandibular symphyseal width is narrower. In contrast, in horizontal growth pattern subjects, the mandibular symphyseal width is wider.

Assessment of Location of Mental Foramen in Mandible Using Cone Beam Computerized Tomography

Objective: To determine the mean distance of mental foramen from the base of the mandible and mandibular symphysis in patients reporting to tertiary care center using Cone Beam Computerized Tomography (CBCT). Study design and setting: Cross-Sectional Study was carried out in the Prosthodontics Department, Foundation University College of Dentistry, Islamabad from March 2019 to August 2019. Methodology: Total 100 patients between the age of 20-45 years were participated. CBCT investigation was carried out and measurements of mental foramen from the base of the mandible and mandibular symphysis in patients were recorded with the help of measuring tools in the software and noted down on the performa. SPSS version 20 was used analyze the data. P value less than 0.05 was considered as statistically significant. . Frequency and percentages were calculated for variable gender (qualitative). For quantitative variables like age, distance mental foramen from the mandibular Symphysis and inferior border of mandible, mean + SD were calculated. Independent samples t-test was used to compare quantitative variables like distance MF from the mandibular symphysis/midline and inferior border of mandible. P values &lt; 0.05 was considered as statistically significant. Results: The Mean+SD distance of anterior border of mental foramen from symphysis on left and right side were 24.12+2.835 and 24.88+2.637 and from the lower border of mandible were 11.97+1.359 and 12.00+1.764 respectively. Conclusion: The mean vertical and horizontal distances calculated in this study can provide a useful guide to dentist to safely place dental implants within the inter-foraminal region in our population

Assessment of Mandibular Ascending Ramus Cortical Plates for Reconstruction of Atrophic Maxillary Ridges Versus Chin Cortical Plates [A Randomized Clinical Trial

Aim of the study: Assessment of the quality and quantity of horizontal bone gain upon using the rami cortical blocks versus chin blocks for horizontal augmentation of atrophic maxillary ridges Patients and Methods: Twenty operation sites in 18 patients suffering from partial edentulism in the maxilla with an inadequate bone width to allow favorable implant placement were selected from the outpatient clinic of Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Cairo University. They were classified after being included in the study into (10 chin group candidate) & (10 ascending ramus candidate). Results: A total of 20 atrophic sites (cases) in 18 patients ranging from 29-54 years old with a mean of 43.4 years were included in the present study (Table 2). The enrolled subjects were randomly divided by alternation into two groups. 10 sites received autogenous block graft harvested from the mandibular symphysis (symphyseal group). Other 10 sites received autogenous block graft harvested from the ascending ramus (ramus group). Conclusion: Thus within the limits of this study the following could be concluded: Ascending ramus onlay blocks showed significant better results than symphyseal onlay blocks regarding both the quality and stability of the grafted volume of bone. Ramus graft harvesting is a more sensitive procedure as compared to symphyseal block graft and requires certain level of surgical skill and experience to be performed successfully.

Does asymmetry in tongue anatomy affect asymmetry in tongue position? Glossectomy and control subjects

Glossectomy surgery removes part of the tongue due to cancer. The resulting anatomical asymmetries may affect motor symmetry. This study examines anatomical and positional tongue asymmetry in glossectomies and controls. The goals are to determine the extent of the anatomical asymmetries, and their effect on resting asymmetry. We expect that patients with unilateral resections will be more asymmetrical than controls, but that their midline tongue will be centered in the oral cavity (OC), because their dentition is unchanged and the tongue will rest in its familiar position. 3-D tongue volumes were extracted from high-resolution MRI data using Matlab. Tongue volumes were calculated for the whole tongue, both halves and the septum using ITK-SNAP. We bisected the OC in the sagittal plane from the mandibular symphysis to the center of the spinal cord. The tongue volume was calculated in each half of the OC. Results showed more anatomical asymmetry in the patients; seven patients and three controls had a volume difference of 3% or more between the left and right tongue. Positional measures showed that the septum was mostly in one half of the OC. When the septum volume was removed, the tongue volume distributed fairly equally in the OC.

Evidence for tactile foraging in pterosaurs: a sensitive tip to the beak of Lonchodraco giganteus (Pterosauria, Lonchodectidae) from the Upper Cretaceous of southern England

The sense of touch is important for hunting and feeding in vertebrates, especially when visual cues are unreliable. Foramina in the jaws and face, associated with nerves and sensory organs, may provide information about feeding. Pterosaurs, many of which had large, well-developed eyes, are often assumed to have been visual feeders. Here, we show that the lonchodectid pterosaur Lonchodraco giganteus (Bowerbank, 1846) has clusters of circular foramina at the anterior mandibular symphysis (the odontoid) and on the lateral margins of the rostrum that indicate enhanced sensitivity of the rostrum tip. This pattern implies tactile foraging. The foramina were likely occupied by Herbst corpuscles or similar integumentary sensory micro-organs (ISO). They presumably served a sensory function at the jaw tip to enhance food gathering. A similar morphology occurs in some avians that feed using tactile cues, including probe feeders such as kiwis, sandpipers, and ibises, tactile hunters such as spoonbills, and filter feeders such as ducks and flamingos. The beak morphology of L. giganteus does not closely resemble that of these birds, and thus its modus operandi for feeding remains speculative, however tactile foraging for fish or invertebrates in shallow water seems likely. Like birds, pterosaurs evolved a diverse range of feeding strategies.