Submandibular Fossa Research Articles

The "sand watch" mandible.

The lingual surface of the mandible's body is commonly indicated as presenting the submandibular and sublingual fossae, which are separated by the mylohyoid line. The mylohyoid line attaches to the mylohyoid muscle (MM). Less attention has been paid to the 'mylohyoid boutonnières', which allow the 'sublingual buttons' to pass through the mylohyoid muscle in the submandibular space. The cone-beam computed tomography files of patients were routinely examined for anatomical studies. Two cases were found with unexpected morphologies of the mandible's body - the mylohyoid lines were incomplete anteriorly, and herniated sublingual tissue determined an additional fossa inferior to that line in the premolar region. That fossa was termed the 'accessory submandibular fossa'. It determined on coronal slices a 'sand watch' contour of the mandible's body. With such a peculiar morphology, the mandible is more prone to fracture. Moreover, when inserting endosseous implants, the procedure should be carefully personalised in such rare cases.

Evaluation of submandibular gland and submandibular fossa: A combined cone beam computed tomography and ultrasound study

Evaluation of submandibular gland and submandibular fossa: A combined cone beam computed tomography and ultrasound study

Mylohyoid Ridge as a Predictor of Available Bone for Implant Placement: A Cone-Beam Computed Tomography (CBCT) Retrospective Observational Study.

Introduction: The posterior mandibular region, due to the presence of vital structures, poses a high risk during implant placement because of its susceptibility to neurovascular injury and perforation of the lingual cortex. A breach in implant length and available bone height may lead to serious intraoperative and postoperative complications. Prediction of the exact location of the inferior alveolar nerve and submandibular fossa anatomy is a prerequisite for ideal implant placement, which is always not possible with conventional radiographic and clinical techniques.Materials and methods: One hundred ten cone-beam computed tomographies (CBCTs) of patients were acquired from the radiological archives of a radiological center in Chennai. DICOM files from CBCT were exported to Bly Sky Plan software. Cross-sections of the second molar and first molar were extracted following the inclusion criteria. The linear dimension between the mandibular canal and mylohyoid ridge and anatomic variables of the submandibular fossa were measured digitally on the left and right sides using software measuring tools. Descriptive statistics were done. The unilateral and bilateral site and gender differences were evaluated. Bone height superior to the mandibular canal was correlated with the submandibular fossa parameters; depth of undercut in the vertical and horizontal directions; and angle of the undercut.Results: The mandibular canal was on average 5.5 mm and 4 mm inferior to the Mylohyoid ridge in the second molar region and first molar region, respectively, with the right and left sides showing no statistically significant difference. The depth of fossa undercut in vertical and horizontal dimensions was higher in the second molar region compared to the first molar region. The height of the deepest point of the undercut in the vertical dimensions showed a positive correlation with the bone available between the mandibular canal and the mylohyoid ridge.Conclusion: Keeping 2 mm of safety factor in consideration, implants can be safely placed up to the mylohyoid ridge in 100% of cases and 2 mm below the mylohyoid ridge in 78.9% of cases in the mandibular second molar region. In keeping with a safety factor of 2 mm, implants can be safely placed up to the mylohyoid ridge in 82.6% of cases and 2 mm below the mylohyoid ridge in 43.1% of cases in the first molar region. A more pronounced undercut was seen in the second molar region than in the first molar region. Deeper fossa undercuts in vertical dimension are associated with more inferior positioning of the mandibular canal.

Assessment of the anterior and caudal extent of inferior alveolar nerve canal, location of inferior alveolar canal and mental foramen, and the depth of submandibular fossa using computed tomography.

Background:A well-versed knowledge of the precise location of various anatomical landmarks is necessary to avoid complications during surgery. The study was conducted for the assessment of the anterior and caudal extent of the inferior alveolar nerve canal, location of inferior alveolar canal and mental foramen, and the depth of the submandibular fossa using computed tomography (CT).Materials and Methods:One hundred CT scans were randomly selected for this study accounting for 200 hemimandibles. Both axial and coronal images were obtained and evaluated concurrently. Results were subjected to statistical analysis for correct inferences.Results:A total of 200 hemimandibles (n = 200) from 100 patients with a mean age was 23.89 ± 1.75 years ranging from 21 to 33 years were evaluated. The mean length of the anterior loop was 0.95 mm for all of the observation combined and measurement range from 0 to 5.1 mm. The total frequency of type I, type II, and type III of mental nerve was found as 71%, 4.5%, and 24.5%, respectively. At the level of the first molar, the mean distance from the center of the inferior alveolar canal to the external surface of the buccal cortex (Q) was 5.44 ± 1.38 mm ranging from 2.4 to 10.4 mm. Furthermore, there was no statistically significant difference in MF-IMB (mental foramen to the inferior border of mandible) between the right and left sides of the mandible. (P = 0.87).Conclusion:Our study demonstrates that analyzing CT scans using the methods described in this study can be a useful tool in avoiding the iatrogenic injuries to inferior alveolar nerve and arteries during various maxillofacial surgical procedures.

Synovial sarcoma of the neck

Synovial sarcomas are rare malignant neoplasms commonly arising from articular tendons and joint capsules. Despite being termed synovial sarcomas due to their histologic similarity to the synovium, they rarely involve a synovial structure. Although they mostly occur in lower extremities, rare cases originating from the thorax, abdomen, head, and neck have also been reported. A 60-year-old male patient was admitted to the hospital with a complaint of swelling in left side of the neck. CT revealed a mass of approximately 6.5x5 cm, occupying the left parapharyngeal space and left submandibular fossa and protruding into the pharynx lumen. The lesion was non-infiltrative, well circumscribed, and uniformly ovoid. The patient underwent surgery, and subsequent pathological examination confirmed the diagnosis of synovial sarcoma. Despite their rarity, synovial sarcomas should be considered, along with Ewing’s sarcoma, rhabdomyosarcoma, and other sarcomas, in the differential diagnosis of a large juxtaarticular mass containing calcifications.

Effect of Submandibular Fossa on Implant Length in the Posterior Mandibular Region.

This retrospective study aims to evaluate the association between submandibular fossa anatomy and implant length in the posterior mandibular region. The study took place from June 1, 2019 to March 1, 2020, during which 295 implants were placed in the posterior mandibular region. Data were reviewed and analyzed from 86,000 patient records that were documented at a private institution. Statistical analysis was performed to assess the association between submandibular fossa anatomy and implant length in the posterior mandibular region. Of the 295 implants, 29.2% were placed in subjects aged 36-45 yr, and 52.9% were male. Of the total population, 52.2% had type P (parallel) submandibular fossa anatomy. The 10-mm implant was the size that was most commonly used (frequency rate, 60.3%). A prevalence of submandibular fossa according to gender showed that 53.8% of males and 50.4% of females had type P (parallel buccal and lingual) plates. A statistically significant difference was found when comparing implant length to different types of submandibular fossa by gender (p < 0.05). And, when association was compared between types of submandibular fossa and implant length, a statistically significant association was found. We conclude that high risk occurs when implants are placed in the mandibular posterior region, because many complications can arise. Proper treatment planning is necessary after complete evaluation using cone-beam computed tomography.

Immediate implant placement in the posterior mandible: A cone beam computed tomography study.

To determine the longest upright and tilted implant that can be placed in posterior mandibular teeth (second premolars [2PM], first molars [1M], and second molars [2M]) in case of immediate implant placement (IIP), respecting a safe distance from the inferior alveolar canal (IAC) and the submandibular fossa, using cone beam computed tomography (CBCT) scans. In CBCT scans of 118 subjects, the following were measured: distance from the tooth apex to the IAC (DTC), lateromedial width of the mandible, classification of mandibular cross-sectional morphology, upright and tilted implant placement simulation, tilting angle that allowed placement of the longest implant. The DTC has shown to be greater for 1M, shorter for 2PM, and even shorter for 2M. Between 70% and 88% of all 2PM, 1M, and 2M present less than 6 mm of DTC. The cross-sectional morphology of the mandible had a tendency to be classified as "undercut" in more posterior regions. For both 4.0- and 5.0-mm implants, more posterior regions resulted in a greater difference in length between the upright and tilted implants. The tilting angle was greater for the more posterior regions. Most of the relationships between age/sex and the morphometric parameters were weak. Lingual concavity is a common clinical finding at the posterior mandibular region, and its occurrence varies according to the tooth type. The great majority of the 2PM, 1M, and 2M present limited available bone between the root apex and the IAC, which stresses the need for careful attention when IIP is planned in this area.

Positioning errors of dental implants and their associations with adjacent structures and anatomical variations: A CBCT-based study.

PurposeThe objective of the present study was to evaluate the prevalence of dental implants positioning errors and their associations with adjacent structures and anatomical variations by means of cone-beam computed tomography (CBCT).Materials and MethodsCBCT images of 207 patients (584 dental implants) were evaluated by 2 oral radiologists. The distance between the implant and the adjacent teeth/implants was measured and classified as adequate (≥1.5 mm and ≥3 mm, respectively) or inadequate. The presence of thread exposure, cortical perforation, implant dehiscence, implant penetration into adjacent structures, and anatomical variations was also recorded. The incisor canal diameter and the depth of the concavity of the submandibular fossa were measured in order to evaluate their correlations with the frequency of implant penetration in these structures. Descriptive analyses, the Fisher exact test, and Spearman correlation analysis were performed (α=0.05).ResultsThe overall prevalence of positioning errors was 82.9%. The most common error was the inadequate distance between the implant and the adjacent teeth/implants. The presence of anatomical variations did not significantly influence the overall prevalence of errors (P>0.05). There was a positive correlation between the diameter of the incisor canal and the frequency of implant penetration in this structure (r=0.232, P<0.05).ConclusionThere was a high prevalence of dental implant positioning errors, and positioning errors were not associated with the presence of anatomical variations. Professionals should be aware of the space available for implant placement during the preoperative planning stage.

Cone-Beam Computed Tomography Evaluation of the Submandibular Fossa in a Group of Dental Implant Patients.

In the mandibular posterior region, presurgical imaging can provide valuable information of anatomical variants. The aim of this study is to evaluate submandibular fossa anatomy in the posterior mandible using cone-beam computed tomography (CBCT) scans. One hundred thirty-two preimplant CBCT examinations were used. Several morphometric measurements were performed in the submandibular fossa. Moreover, each patient was classified according to the Kennedy classification. Statistical analysis was used to test the relationship among measurements, sex, side, and each tooth. A total of 2412 measurements were performed from all patients. The deepest concavity at the submandibular fossa in all Kennedy Class groups was in the 1st and 2nd molars. The concavity depth was statistically higher in class I group for 1st and 2nd molars than the other Kennedy Class groups. Class IV group showed less depth than the other groups. When compared with female patients, all measurements in male patients were statistically higher. The patients older than 35 years showed higher measurements than the patients younger than 35 years. Mandibles with any lingual concavity pose a potential increased risk of lingual cortical perforation during surgery. This study revealed that the alveolar bone resorption occurs both vertically and horizontally, and the preservation of teeth can limit the bone resorption.

PR617: CBCT evaluation of submandibular fossa in a group of Turkish patients

PR617: CBCT evaluation of submandibular fossa in a group of Turkish patients

Assessment of Lingual Concavities in Submandibular Fossa Region in Patients requiring Dental Implants– A Cone Beam Computed Tomography Study

The present study was aimed at assessing the lingual concavities in the submandibular fossa region in patients requiring dental implants with the help of cone beam computed tomography (CBCT). The present study included 140 patients who visited the department with the missing mandibular posterior teeth. CBCT images were obtained using planmeca machine. Cross sections of 1 mm of submandibular fossa in the region of 1st and 2nd molar were studied and Type I to III lingual concavities were analyzed by a radiologist. Type I lingual concavity (< 2 mm) was seen in 23%, type II (2-3 mm) in 62% and Type III (> 3 mm) in 15% of patients. The difference was significant (p < 0.05). Males had slightly higher mean ± S.D value at 1st molar (2.6 mm ± 0.94) and 2nd molar (2.8 mm ± 0.90) on the left side and (2.7 mm ± 0.92) at 1st molar and (2.9 mm ± 0.93) at 2nd molar on the right side. The difference was nonsignificant (p > 0.05). Females had mean ± S.D value at 1st molar (2.3 mm ± 0.90) and (2.5 mm ± 0.92) at 2nd molar on the left side and (2.4 mm ± 0.91) at 1st molar and (2.8 mm ± 0.93) at 2nd molar. The difference was nonsignificant (p > 0.05. The difference between both genders was statistically nonsignificant (p > 0.05). Type I bone is the best for placing an implant. The chances of complications are more in type II and III bone. CBCT provides necessary information before planning implant in the edentulous area. Cone beam computed tomography (CBCT) is the best radiographic aid which is effective in delineating different types of bone in the mandibular posterior region.

Assesment of submandibular fossa depth using cone beam computed tomography

Assesment of submandibular fossa depth using cone beam computed tomography

Correlation between the visibility of submandibular fossa and mandibular canal cortication on panoramic radiographs and submandibular fossa depth on CBCT.

BackgroundTo identify a correlation between the submandibular fossa (SF) visibility and mandibular canal (MC) cortication on panoramic image and the depth of SF measured on CBCT and also correlation between the depth of SF and vertical and horizontal location of MC on CBCT.Material and Methods500 CBCT scans and panoramic radiographs were evaluated. SF depth types were classified as type I (< 2mm); type II (2-3mm) and type III (> 3mm) on CBCT. Visibility of SF and the cortication of MC on panoramic radiographs were compared with the depth of SF on CBCT. Distances between MC and mandibular inferior, buccal and lingual cortices were measured.ResultsNo statistically significant correlation was found between radiolucent appearances of SF, cortication of MC, and depth of SF. The deepest part of the fossa was in the second molar area followed by third and first molars. Negative weak correlations were found between B-MC, L-MC distances and depth of SF.ConclusionsVisibility of SF and cortication of MC on panoramic radiographs did not correlate with the depth of SF. A marked radiolucent submandibular fossa on panoramic image does not undoubtedly indicate a deep fossa, which emphasizes the importance of 3-D imaging in implant planning. Key words:Cone beam computed tomography, panoramic radiography, dental implants, submandibular fossa, intraoperative complications, mandible, mandibular nerve.

Second premolar agenesis is associated with mandibular form: a geometric morphometric analysis of mandibular cross-sections.

The aim of this study was to compare mandibular form (i.e., size and shape) between patients with agenesis of the lower second premolar (P2) and a control group with no agenesis. Three hypotheses were tested: (H1) agenesis causes a change in mandibular morphology because of inadequate alveolar ridge development in the area of the missing tooth (mandibular plasticity); (H2) agenesis is caused by spatial limitations within the mandible (dental plasticity); and (H3) common genetic/epigenetic factors cause agenesis and affect mandibular form (pleiotropy). A geometric morphometric analysis was applied to cross-sectional images of computed tomography (CT) scans of three matched groups (n=50 each): (1) regularly erupted P2; (2) agenesis of P2 and the primary second molar in situ; and (3) agenesis of P2 and the primary second molar missing for >3 months. Cross-sections of the three areas of interest (first premolar, P2, first molar) were digitized with 23 landmarks and superimposed by a generalized Procrustes analysis. On average, the mandibular cross-sections were narrower and shorter in patients with P2 agenesis compared with that in the control group. Both agenesis groups featured a pronounced submandibular fossa. These differences extended at least one tooth beyond the agenesis-affected region. Taken together with the large interindividual variation that resulted in massively overlapping group distributions, these findings support genetic and/or epigenetic pleiotropy (H3) as the most likely origin of the observed covariation between mandibular form and odontogenesis. Clinically, reduced dimensions and greater variability of mandibular form, as well as a pronounced submandibular fossa, should be expected during the treatment planning of patients with P2 agenesis.

Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery

The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth, bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region and planning for safe implant installation in the posterior mandible. Furthermore, comprehensive evaluation of the characteristics of this region is necessary, as the variables – submandibular fossa depth, bone height and thickness, and mandibular canal corticalization – are related and must be considered together when planning.

Retrospective study of the bone morphology in the posterior mandibular region. Evaluation of the prevalence and the degree of lingual concavity and their possible complications

BackgroundIn order to choose the appropriate implant size and to prevent complications, an oral surgeon must know the size and shape of the mandible. In the posterior mandibular region, a lingual undercut is often found and could represent a difficulty hard to manage if a lingual or buccal perforation occur. A large series of computed tomography (CT) images of the mandibular first molar was evaluated and the bone morphology, the prevalence and the degree of the lingual concavity in the first molar region were studied.Material and MethodsOne hundred and fifty-one computed tomography (CT) examinations of patients were retrospectively evaluated to determine anatomical variations in bone morphology in the submandibular fossa region.ResultsA total of 151 subjects were included, consisting of 64 males (M) (42.4%) and 87 females (F) (57.6%). The under-cut type ridge was present in 64.2% of the cases. The concavity angle was 66.6 ± 8.9° (M) and 71.6 ± 8.4° (F) and the linear concavity depth 4.5 ± 2.3 mm (M) and 3.1 ± 1.7 mm (F) (p>0.05).ConclusionsMandibles with any lingual concavity present a potential increased risk of lingual cortical perforation during implant placement surgery. CT imaging allows characterizing the anatomy of the submandibular fossa and provides other important information for the preoperative assessment of the posterior mandible for dental implants placement. Key words:Anatomy, computed tomography, dental implants, intraoperative complications, mandible, panoramic radiography, radiographic examination.

Displacement of lower third molar to Submandibular fossa during extraction

Complications during the procedure of extraction can be immediate or postoperative. Some of the immediate complications are fracture of the tooth, fracture of alveolar plate, fracture of mandible, loss of tooth or root into either pharynx or soft tissues, damage to nerves or vessels, soft tissue damage, involvement of maxillary antrum, dislocation of temporomandibular joint, etc., whereas hemorrhage, dry socket, osteomyelitis, swelling, pain, ecchymosis, trismus, prolonged anesthesia, and infective endocarditis are the various postoperative complications of extraction. This report discusses a case of displaced mandibular third molar into submandibular space while attempting extraction of the same.

Anatomical Measurement of Presence, Horizontal Distance and Vertical Distance of Submandibular Fossa

AIM: To determine the anatomical measurement of presence, horizontal distance and vertical distance of submandibular fossa. The submandibular fossa is a fossa in the mandible for the submandibular gland. It is a shallow depression on either side on the inner surface of the body of the mandible, inferior to the mylohyoid line, lodging the submandibular gland. Using the dried mandibles, the horizontal distance from the position of the mental foramen as well as the vertical distance between the inferior border of the mandible and the mylohyoid line were measured at definite points.There were no significant statistical difference in genders, sides, and tooth loss.The main aim of this study is that the horizontal and the vertical distances of the submandibular fossa are determined for the purpose of placing the dental implants such as endosseousimplants.

Tomographic evaluation on bone morphology in posterior mandibular region for safe placement of dental implant.

The aim of this study was to examine the morphology of submandibular fossae at edentulous posterior regions of dried mandibles and to determine a safe range for proper lingual angulation during the placement of a dental implant in the posterior mandibular region, with a computerized tomographic scan study. Spiral computed tomographic images of 77 dry adult human mandibles were evaluated to determine the deepest area in the submandibular fossa. Then, the proper lingual angulations for the placement of a dental implant at these regions were measured. Pearson's correlation coefficient was calculated to show the relation between the depths of submandibular fossa and lingual implant angulations. "Paired t test" was used for differences between the lingual implant angulations and the depths of submandibular fossa on each side of the mandibles. Depths of the submandibular fossa and lingual implant angulations were varied between 1.1 and 4.6 mm: 62°-84° on right side of the mandibles, and 1.1-4.5 mm, 65°-83° on left side of the mandibles. There were statistically medium negative correlations between the degree of lingual implant angulations and the depth of submandibular fossa on each side of the mandible (r = -0.44, p < 0.001, and r = -0.38, p = 0.001). There was a statistically significant difference between the right and left sides of the mandibles in terms of the depth of submandibular fossa (p = 0.01). Within the limits of this study, the depth of submandibular fossa was measured as ≥ 2 mm in around 71.5 % of examined regions, and lingual implant angulations were between 62° and 84°. These results may be considered by clinicians who are planning the dental implant placement in posterior mandible to avoid potential risk of lingual cortical plate perforation.

Evaluation of submandibular fossa using computed tomography and panoramic radiography

Objective We aimed to evaluate the correlation between the depth of the submandibular fossa (SF) using computed tomography (CT) and the visibility of the SF and mandibular canal (MC) on panoramic images.